Andrew R. Hoffman, MD

All Publications

• Management of Incidental Pituitary Findings on CT, MRI, and F-18-Fluorodeoxyglucose PET: A White Paper of the ACR Incidental Findings Committee JOURNAL OF THE AMERICAN COLLEGE OF RADIOLOGY Hoang, J. K., Hoffman, A. R., Gonzalez, R., Wintermark, M., Glenn, B. J., Pandharipande, P. V., Berland, L. L., Seidenwurm, D. J. 2018; 15 (7): 966–72

  Abstract

  The ACR Incidental Findings Committee presents recommendations for managing pituitary findings that are incidentally detected on CT, MRI and 18F-fluorodeoxyglucose PET. The Pituitary Subcommittee, which included radiologists practicing neuroradiology and an endocrinologist, developed this algorithm. The recommendations draw from published evidence and expert opinion and were finalized by informal iterative consensus. Algorithm branches successively categorize pituitary findings on the basis of imaging features. They terminate with an ascertainment of an indolent lesion (with sufficient confidence to discontinue follow-up) or a management recommendation. The algorithm addresses most, but not all, pathologies and clinical scenarios. The goal is to improve the quality of care by providing guidance on how to manage incidentally detected pituitary findings.

  View details for DOI 10.1016/j.jacr.2018.03.037

  View details for Web of Science ID 000437995100011

  View details for PubMedID 29735244

• Mitochondrial peptides modulate mitochondrial function during cellular senescence AGING-US Kim, S., Mehta, H. H., Wan, J., Kuehnemann, C., Chen, J., Hu, J., Hoffman, A. R., Cohen, P. 2018; 10 (6): 1239–56

  Abstract

  Cellular senescence is a complex cell fate response that is thought to underlie several age-related pathologies. Despite a loss of proliferative potential, senescent cells are metabolically active and produce energy-consuming effectors, including senescence-associated secretory phenotypes (SASPs). Mitochondria play crucial roles in energy production and cellular signaling, but the key features of mitochondrial physiology and particularly of mitochondria-derived peptides (MDPs), remain underexplored in senescence responses. Here, we used primary human fibroblasts made senescent by replicative exhaustion, doxorubicin or hydrogen peroxide treatment, and examined the number of mitochondria and the levels of mitochondrial respiration, mitochondrial DNA methylation and the mitochondria-encoded peptides humanin, MOTS-c, SHLP2 and SHLP6. Senescent cells showed increased numbers of mitochondria and higher levels of mitochondrial respiration, variable changes in mitochondrial DNA methylation, and elevated levels of humanin and MOTS-c. Humanin and MOTS-c administration modestly increased mitochondrial respiration and selected components of the SASP in doxorubicin-induced senescent cells partially via JAK pathway. Targeting metabolism in senescence cells is an important strategy to reduce SASP production for eliminating the deleterious effects of senescence. These results provide insight into the role of MDPs in mitochondrial energetics and the production of SASP components by senescent cells.

  View details for DOI 10.18632/aging.101463

  View details for Web of Science ID 000437446300009

  View details for PubMedID 29886458

  View details for PubMedCentralID PMC6046248

• AMERICAN ASSOCIATION OF CLINICAL ENDOCRINOLOGISTS AND AMERICAN COLLEGE OF ENDOCRINOLOGY DISEASE STATE CLINICAL REVIEW: DIAGNOSIS OF RECURRENCE IN CUSHING DISEASE ENDOCRINE PRACTICE Fleseriu, M., Hamrahian, A. H., Hoffman, A. R., Kelly, D. F., Katznelson, L. 2016; 22 (12): 1436-1448

  Abstract

  Recurrence of hypercortisolemia after initial treatment of Cushing disease (CD) is more common than previously thought, with a third of patients suffering a recurrence over their lifetime. Awareness of this high rate and delayed timeline (sometimes decades) of potential recurrence is critical and patients with CD should be monitored at regular intervals throughout their lives. In this manuscript, we review the complex evaluation needed for defining CD remission versus persistent disease after surgery, and focus on challenges in diagnosing early recurrent hypercortisolemia. Late night salivary cortisol appears to be an earlier predictor of recurrence when compared with urinary free cortisol (UFC) excretion. We also review the criteria suggested to define recurrence of hypercortisolemia in patients treated with medical therapy. Further research is needed to determine the optimal way to evaluate a patient with CD recurrence as well as the riskbenefit ratio of treatment in early, mild recurrent disease.ACTH = adrenocorticotropic hormone AI = adrenal insufficiency CD = Cushing disease CDDT = coupled dexamethasone desmopressin test CR = circadian rhythm CRH = corticotropin-releasing hormone GC = glucocorticoid GCR = global clinical response HPA = hypothalamic-pituitary-adrenal LDDST = low-dose dexamethasone suppression test LNSC = late-night salivary cortisol ODST = overnight dexamethasone suppression test TSS = trans-sphenoidal surgery.

  View details for DOI 10.4158/EP161512.DSCR

  View details for Web of Science ID 000389843300011

  View details for PubMedID 27643842

• Loss of insulin-like growth factor II imprinting is a hallmark associated with enhanced chemo/radiotherapy resistance in cancer stem cells ONCOTARGET Zhao, X., Liu, X., Wang, G., Wen, X., Zhang, X., Hoffman, A. R., Li, W., Hu, J., Cui, J. 2016; 7 (32): 51349-51364

  Abstract

  Insulin-like growth factor II (IGF2) is maternally imprinted in most tissues, but the epigenetic regulation of the gene in cancer stem cells (CSCs) has not been defined. To study the epigenetic mechanisms underlying self-renewal, we isolated CSCs and non-CSCs from colon cancer (HT29, HRT18, HCT116), hepatoma (Hep3B), breast cancer (MCF7) and prostate cancer (ASPC) cell lines. In HT29 and HRT18 cells that show loss of IGF2 imprinting (LOI), IGF2 was biallelically expressed in the isolated CSCs. Surprisingly, we also found loss of IGF2 imprinting in CSCs derived from cell lines HCT116 and ASPC that overall demonstrate maintenance of IGF2 imprinting. Using chromatin conformation capture (3C), we found that intrachromosomal looping between the IGF2 promoters and the imprinting control region (ICR) was abrogated in CSCs, in parallel with loss of IGF2 imprinting in these CSCs. Loss of imprinting led to increased IGF2 expression in CSCs, which have a higher rate of colony formation and greater resistance to chemotherapy and radiotherapy in vitro. These studies demonstrate that IGF2 LOI is a common feature in CSCs, even when the stem cells are derived from a cell line in which the general population of cells maintain IGF2 imprinting. This finding suggests that aberrant IGF2 imprinting may be an intrinsic epigenetic control mechanism that enhances stemness, self-renewal and chemo/radiotherapy resistance in cancer stem cells.

  View details for DOI 10.18632/oncotarget.9784

  View details for Web of Science ID 000385429100047

  View details for PubMedCentralID PMC5239480

• Long noncoding RNA-mediated intrachromosomal interactions promote imprinting at the Kcnq1 locus JOURNAL OF CELL BIOLOGY Zhang, H., Zeitz, M. J., Wang, H., Niu, B., Ge, S., Li, W., Cui, J., Wang, G., Qian, G., Higgins, M. J., Fan, X., Hoffman, A. R., Hu, J. 2014; 204 (1): 61-75

  Abstract

  Kcnq1ot1 is a long noncoding ribonucleic acid (RNA; lncRNA) that participates in the regulation of genes within the Kcnq1 imprinting domain. Using a novel RNA-guided chromatin conformation capture method, we demonstrate that the 5' region of Kcnq1ot1 RNA orchestrates a long-range intrachromosomal loop between KvDMR1 and the Kcnq1 promoter that is required for maintenance of imprinting. PRC2 (polycomb repressive complex 2), which participates in the allelic repression of Kcnq1, is also recruited by Kcnq1ot1 RNA via EZH2. Targeted suppression of Kcnq1ot1 lncRNA prevents the creation of this long-range intrachromosomal loop and causes loss of Kcnq1 imprinting. These observations delineate a novel mechanism by which an lncRNA directly builds an intrachromosomal interaction complex to establish allele-specific transcriptional gene silencing over a large chromosomal domain.

  View details for DOI 10.1083/jcb.201304152

  View details for Web of Science ID 000329347100007

  View details for PubMedID 24395636

• Implications of COMT long-range interactions on the phenotypic variability of 22q11.2 deletion syndrome. Nucleus (Austin, Tex.) Zeitz, M. J., Lerner, P. P., Ay, F., Van Nostrand, E., Heidmann, J. D., Noble, W. S., Hoffman, A. R. 2013; 4 (6): 487-493

  Abstract

  22q11.2 deletion syndrome (22q11DS) results from a hemizygous microdeletion on chromosome 22 and is characterized by extensive phenotypic variability. Penetrance of signs, including congenital heart, craniofacial, and neurobehavioral abnormalities, varies widely and is not well correlated with genotype. The three-dimensional structure of the genome may help explain some of this variability. The physical interaction profile of a given gene locus with other genetic elements, such as enhancers and co-regulated genes, contributes to its regulation. Thus, it is possible that regulatory interactions with elements outside the deletion region are disrupted in the disease state and modulate the resulting spectrum of symptoms. COMT, a gene within the commonly deleted ~3 Mb region has been implicated as a contributor to the neurological features frequently found in 22q11DS patients. We used this locus as bait in a 4C-seq experiment to investigate genome-wide interaction profiles in B lymphocyte and fibroblast cell lines derived from both 22q11DS and unaffected individuals. All normal B lymphocyte lines displayed local, conserved chromatin looping interactions with regions that are lost in atypical and distal deletions, which may mediate similarities between typical, atypical, and distal 22q11 deletion phenotypes. There are also distinct clusterings of cis interactions based on disease state. We identified regions of differential trans interactions present in normal, and lost in deletion-carrying, B lymphocyte cell lines. This data suggests that hemizygous chromosomal deletions such as 22q11DS can have widespread effects on chromatin organization, and may contribute to the inherent phenotypic variability.

  View details for DOI 10.4161/nucl.27364

  View details for PubMedID 24448439

• Genomic Interaction Profiles in Breast Cancer Reveal Altered Chromatin Architecture PLOS ONE Zeitz, M. J., Ay, F., Heidmann, J. D., Lerner, P. L., Noble, W. S., Steelman, B. N., Hoffman, A. R. 2013; 8 (9)

  Abstract

  Gene transcription can be regulated by remote enhancer regions through chromosome looping either in cis or in trans. Cancer cells are characterized by wholesale changes in long-range gene interactions, but the role that these long-range interactions play in cancer progression and metastasis is not well understood. In this study, we used IGFBP3, a gene involved in breast cancer pathogenesis, as bait in a 4C-seq experiment comparing normal breast cells (HMEC) with two breast cancer cell lines (MCF7, an ER positive cell line, and MDA-MB-231, a triple negative cell line). The IGFBP3 long-range interaction profile was substantially altered in breast cancer. Many interactions seen in normal breast cells are lost and novel interactions appear in cancer lines. We found that in HMEC, the breast carcinoma amplified sequence gene family (BCAS) 1-4 were among the top 10 most significantly enriched regions of interaction with IGFBP3. 3D-FISH analysis indicated that the translocation-prone BCAS genes, which are located on chromosomes 1, 17, and 20, are in close physical proximity with IGFBP3 and each other in normal breast cells. We also found that epidermal growth factor receptor (EGFR), a gene implicated in tumorigenesis, interacts significantly with IGFBP3 and that this interaction may play a role in their regulation. Breakpoint analysis suggests that when an IGFBP3 interacting region undergoes a translocation an additional interaction detectable by 4C is gained. Overall, our data from multiple lines of evidence suggest an important role for long-range chromosomal interactions in the pathogenesis of cancer.

  View details for DOI 10.1371/journal.pone.0073974

  View details for Web of Science ID 000324338200085

  View details for PubMedID 24019942

• Intrachromosomal Looping Is Required for Activation of Endogenous Pluripotency Genes during Reprogramming CELL STEM CELL Zhang, H., Jiao, W., Sun, L., Fan, J., Chen, M., Wang, H., Xu, X., Shen, A., Li, T., Niu, B., Ge, S., Li, W., Cui, J., Wang, G., Sun, J., Fan, X., Hu, X., Mrsny, R. J., Hoffman, A. R., Hu, J. 2013; 13 (1): 30-35

  Abstract

  Generation of induced pluripotent stem cells (iPSCs) by defined factors is an extremely inefficient process, because there is a strong epigenetic block preventing cells from achieving pluripotency. Here we report that virally expressed factors bound to the promoters of their target genes to the same extent in both iPSCs and unreprogrammed cells (URCs). However, expression of endogenous pluripotentcy genes was observed only in iPSCs. Comparison of local chromatin structure of the OCT4 locus revealed that there was a cohesin-complex-mediated intrachromosomal loop that juxtaposes a downstream enhancer to the gene's promoter, enabling activation of endogenous stemness genes. None of these long-range interactions were observed in URCs. Knockdown of the cohesin-complex gene SMC1 by RNAi abolished the intrachromosomal interaction and affected pluripotency. These findings highlight the importance of the SMC1-orchestrated intrachromosomal loop as a critical epigenetic barrier to the induction of pluripotency.

  View details for DOI 10.1016/j.stem.2013.05.012

  View details for Web of Science ID 000329570100010

  View details for PubMedID 23747202

• Interruption of intrachromosomal looping by CCCTC binding factor decoy proteins abrogates genomic imprinting of human insulin-like growth factor II JOURNAL OF CELL BIOLOGY Zhang, H., Niu, B., Hu, J., Ge, S., Wang, H., Li, T., Ling, J., Steelman, B. N., Qian, G., Hoffman, A. R. 2011; 193 (3): 475-487

  Abstract

  Monoallelic expression of IGF2 is regulated by CCCTC binding factor (CTCF) binding to the imprinting control region (ICR) on the maternal allele, with subsequent formation of an intrachromosomal loop to the promoter region. The N-terminal domain of CTCF interacts with SUZ12, part of the polycomb repressive complex-2 (PRC2), to silence the maternal allele. We synthesized decoy CTCF proteins, fusing the CTCF deoxyribonucleic acid-binding zinc finger domain to CpG methyltransferase Sss1 or to enhanced green fluorescent protein. In normal human fibroblasts and breast cancer MCF7 cell lines, the CTCF decoy proteins bound to the unmethylated ICR and to the IGF2 promoter region but did not interact with SUZ12. EZH2, another part of PRC2, was unable to methylate histone H3-K27 in the IGF2 promoter region, resulting in reactivation of the imprinted allele. The intrachromosomal loop between the maternal ICR and the IGF2 promoters was not observed when IGF2 imprinting was lost. CTCF epigenetically governs allelic gene expression of IGF2 by orchestrating chromatin loop structures involving PRC2.

  View details for DOI 10.1083/jcb.201101021

  View details for Web of Science ID 000290676400008

  View details for PubMedID 21536749

• Systematic review: The safety and efficacy of growth hormone in the healthy elderly ANNALS OF INTERNAL MEDICINE Liu, H., Bravata, D. M., Olkin, I., Nayak, S., Roberts, B., Garber, A. M., Hoffman, A. R. 2007; 146 (2): 104-115

  Abstract

  Human growth hormone (GH) is widely used as an antiaging therapy, although its use for this purpose has not been approved by the U.S. Food and Drug Administration and its distribution as an antiaging agent is illegal in the United States.To evaluate the safety and efficacy of GH therapy in the healthy elderly.The authors searched MEDLINE and EMBASE databases for English-language studies published through 21 November 2005 by using such terms as growth hormone and aging.The authors included randomized, controlled trials that compared GH therapy with no GH therapy or GH and lifestyle interventions (exercise with or without diet) with lifestyle interventions alone. Included trials provided GH for 2 weeks or more to community-dwelling participants with a mean age of 50 years or more and a body mass index of 35 kg/m2 or less. The authors excluded studies that evaluated GH as treatment for a specific illness.Two authors independently reviewed articles and abstracted data.31 articles describing 18 unique study populations met the inclusion criteria. A total of 220 participants who received GH (107 person-years) completed their respective studies. Study participants were elderly (mean age, 69 years [SD, 6]) and overweight (mean body mass index, 28 kg/m2 [SD, 2]). Initial daily GH dose (mean, 14 microg per kg of body weight [SD, 7]) and treatment duration (mean, 27 weeks [SD, 16]) varied. In participants treated with GH compared with those not treated with GH, overall fat mass decreased (change in fat mass, -2.1 kg [95% CI, -2.8 to -1.35] and overall lean body mass increased (change in lean body mass, 2.1 kg [CI, 1.3 to 2.9]) (P < 0.001), and their weight did not change significantly (change in weight, 0.1 kg [CI, -0.7 to 0.8]; P = 0.87). Total cholesterol levels decreased (change in cholesterol, -0.29 mmol/L [-11.21 mg/dL]; P = 0.006), although not significantly after adjustment for body composition changes. Other outcomes, including bone density and other serum lipid levels, did not change. Persons treated with GH were significantly more likely to experience soft tissue edema, arthralgias, carpal tunnel syndrome, and gynecomastia and were somewhat more likely to experience the onset of diabetes mellitus and impaired fasting glucose.Some important outcomes were infrequently or heterogeneously measured and could not be synthesized. Most included studies had small sample sizes.The literature published on randomized, controlled trials evaluating GH therapy in the healthy elderly is limited but suggests that it is associated with small changes in body composition and increased rates of adverse events. On the basis of this evidence, GH cannot be recommended as an antiaging therapy.

  View details for Web of Science ID 000243901000004

  View details for PubMedID 17227934

• CTCF mediates interchromosomal colocalization between Igf2/H19 and Wsb1/Nf1 SCIENCE Ling, J. Q., Li, T., Hu, J. F., Vu, T. H., Chen, H. L., Qiu, X. W., Cherry, A. M., Hoffman, A. R. 2006; 312 (5771): 269-272

  Abstract

  Gene transcription may be regulated by remote enhancer or insulator regions through chromosome looping. Using a modification of chromosome conformation capture (3C) and fluorescence in situ hybridization, we found that one allele of the insulin-like growth factor 2 (Igf2)/H19 imprinting control region (ICR) on chromosome 7 colocalized with one allele of Wsb1/Nf1 on chromosome 11. Omission of CCCTC-binding factor (CTCF) or deletion of the maternal ICR abrogated this association and altered Wsb1/Nf1 gene expression. These findings demonstrate that CTCF mediates an interchromosomal association, perhaps by directing distant DNA segments to a common transcription factory, and the data provide a model for long-range allele-specific associations between gene regions on different chromosomes that suggest a framework for DNA recombination and RNA trans-splicing.

  View details for DOI 10.1126/science.1123191

  View details for Web of Science ID 000236765300050

  View details for PubMedID 16614224

• A methylated oligonucleotide inhibits IGF2 expression and enhances survival in a model of hepatocellular carcinoma JOURNAL OF CLINICAL INVESTIGATION Yao, X. M., Hu, J. F., Daniels, M., Shiran, H., Zhou, X. J., Yan, H. F., Lu, H. Q., Zeng, Z. L., Wang, Q. X., Li, T., Hoffman, A. R. 2003; 111 (2): 265-273

  Abstract

  IGF-II is a mitogenic peptide that has been implicated in hepatocellular oncogenesis. Since the silencing of gene expression is frequently associated with cytosine methylation at cytosine-guanine (CpG) dinucleotides, we designed a methylated oligonucleotide (MON1) complementary to a region encompassing IGF2 promoter P4 in an attempt to induce DNA methylation at that locus and diminish IGF2 mRNA levels. MON1 specifically inhibited IGF2 mRNA accumulation in vitro, whereas an oligonucleotide (ON1) with the same sequence but with nonmethylated cytosines had no effect on IGF2 mRNA abundance. MON1 treatment led to the specific induction of de novo DNA methylation in the region of IGF2 promoter hP4. Cells from a human hepatocellular carcinoma (HCC) cell line, Hep 3B, were implanted into the livers of nude mice, resulting in the growth of large tumors. Animals treated with MON1 had markedly prolonged survival as compared with those animals treated with saline or a truncated methylated oligonucleotide that did not alter IGF2 mRNA levels in vitro. This study demonstrates that a methylated sense oligonucleotide can be used to induce epigenetic changes in the IGF2 gene and that inhibition of IGF2 mRNA accumulation may lead to enhanced survival in a model of HCC.

  View details for DOI 10.1172/JCI200315109

  View details for Web of Science ID 000180672900018

  View details for PubMedID 12531883

• Imprinting of the Angelman syndrome gene, UBE3A, is restricted to brain NATURE GENETICS Vu, T. H., Hoffman, A. R. 1997; 17 (1): 12-13

  View details for Web of Science ID A1997XU72400007

  View details for PubMedID 9288087

• PROMOTER-SPECIFIC IMPRINTING OF THE HUMAN INSULIN-LIKE GROWTH FACTOR-II GENE NATURE Vu, T. H., Hoffman, A. R. 1994; 371 (6499): 714-717

  Abstract

  Genomic imprinting is a mechanism whereby only one of the two parental alleles is expressed. Loss or relaxation of genomic imprinting has been proposed as an epigenetic mechanism for oncogenesis in a variety of human tumours. Although the mechanism of imprinting is unknown, differential CpG methylation of the parental alleles has been implicated. The human insulin-like growth factor-II (IGF2) gene, which is transcribed from four promoters, P1-P4 (ref. 13), is imprinted in fetal liver but biallelic expression occurs in adult liver. Like most tissues, fetal liver uses primarily promoters P3 and P4 (ref. 17). Adult liver, however, transcribes IGF2 from promoter P1, and it has been suggested that the recruitment of P1 may be responsible for the absence of imprinting in human liver, and in choroid plexus and leptomeninges. We report here that in liver and chondrocytes, IGF2 transcripts from promoter P1 are always derived from both parental alleles, whereas transcripts from promoters P2, P3 and P4 are always from one parental allele. These findings demonstrate that imprinting and a lack of imprinting can both occur within a single gene in a single tissue, suggesting that regional imprinting factors may be important.

  View details for Web of Science ID A1994PM77300060

  View details for PubMedID 7935819

• Associations Between Lean Mass, Muscle Strength and Power, and Skeletal Size, Density and Strength in Older Men JOURNAL OF BONE AND MINERAL RESEARCH Chalhoub, D., Boudreau, R., Greenspan, S., Newman, A. B., Zmuda, J., Frank-Wilson, A. W., Nagaraj, N., Hoffman, A. R., Lane, N. E., Stefanick, M. L., Barrett-Connor, E., Dam, T., Cawthon, P. M., Orwoll, E. S., Cauley, J. A., Osteoporotic Fractures Men MrOS 2018; 33 (9): 1612–21

  Abstract

  Studies examining the relationship between muscle parameters and bone strength have not included multiple muscle measurements and/or both central and peripheral skeletal parameters. The purpose of this study was to explore the relationship between lean mass, muscle strength and power, and skeletal size, bone density, and bone strength. We studied the association between appendicular lean mass (ALM), grip strength, and leg power, and central quantitative computed tomography (QCT) parameters in 2857 men aged 65 years or older; peripheral QCT was available on a subset (n = 786). ALM, grip strength, and leg power were measured by dual-energy X-ray absorptiometry (DXA), Jamar dynamometer, and the Nottingham Power Rig, respectively. Multivariable models adjusting for potential confounders including age, race, study site, BMI, and muscle measurements were developed and least squares means were generated from linear regression models. For the multivariable model, percent differences of bone parameters between lowest (Q1) and highest quartiles (Q4) of ALM, grip strength, and leg power were reported. ALM was significantly associated with central and peripheral QCT parameters: percent higher values (Q4 versus Q1) ranging from 3.3% (cortical volumetric bone mineral density [vBMD] of the femoral neck) to 31% (vertebral strength index of the spine). Grip strength was only significantly associated with radial parameters: percent higher values (Q4 versus Q1) ranging from 2.5% (periosteal circumference) to 7.5% (33% axial strength index [SSIx]). Leg power was associated with vertebral strength and lower cross-sectional area with percent lower values (Q4 versus Q1) of -11.9% and -2.7%, respectively. In older men, stronger associations were observed for ALM compared to muscle strength and power. Longitudinal studies are needed to examine the relationship between independent changes in muscle measurements and skeletal size, density and strength. © 2018 American Society for Bone and Mineral Research.

  View details for DOI 10.1002/jbmr.3458

  View details for Web of Science ID 000443230400009

  View details for PubMedID 29701926

• Clinical and Immunohistochemical Analysis of Clinically Non-functional Pituitary Neuroendocrine Tumors Lavezo, J., Frankel, M., Balliu, B., Pan, J., Hoffman, A., Dodd, R., Harsh, G., Katznelson, L., Vogel, H. OXFORD UNIV PRESS INC. 2018: 518

  View details for Web of Science ID 000434064400162

• Epigenetic Targeting of Granulin in Hepatoma Cells by Synthetic CRISPR dCas9 Epi-suppressors MOLECULAR THERAPY-NUCLEIC ACIDS Wang, H., Guo, R., Du, Z., Bai, L., Li, L., Cui, J., Li, W., Hoffman, A. R., Hu, J. 2018; 11: 23–33

  Abstract

  The CRISPR-associated Cas9 system can modulate disease-causing alleles both in vivo and ex vivo, raising the possibility of therapeutic genome editing. In addition to gene targeting, epigenetic modulation by the catalytically inactive dCas9 may also be a potential form of cancer therapy. Granulin (GRN), a potent pluripotent mitogen and growth factor that promotes cancer progression by maintaining self-renewal of hepatic stem cancer cells, is upregulated in hepatoma tissues and is associated with decreased tumor survival in patients with hepatoma. We synthesized a group of dCas9 epi-suppressors to target GRN by tethering the C terminus of dCas9 with three epigenetic suppressor genes: DNMT3a (DNA methyltransferase), EZH2 (histone 3 lysine 27 methyltransferase), and KRAB (the Krüppel-associated box transcriptional repression domain). In conjunction with guide RNAs (gRNAs), the dCas9 epi-suppressors caused significant decreases in GRN mRNA abundance in Hep3B hepatoma cells. These dCas9 epi-suppressors initiated de novo CpG DNA methylation in the GRN promoter, and they produced histone codes that favor gene suppression, including decreased H3K4 methylation, increased H3K9 methylation, and enhanced HP1a binding. Epigenetic knockdown of GRN led to the inhibition of cell proliferation, decreased tumor sphere formation, and reduced cell invasion. These changes were achieved at least partially through the MMP/TIMP pathway. This study thus demonstrates the potential utility of using dCas9 epi-suppressors in the development of epigenetic targeting against tumors.

  View details for DOI 10.1016/j.omtn.2018.01.002

  View details for Web of Science ID 000433428900003

  View details for PubMedID 29858058

  View details for PubMedCentralID PMC5849805

• Serum Sodium and Cognition in Older Community-Dwelling Men CLINICAL JOURNAL OF THE AMERICAN SOCIETY OF NEPHROLOGY Nowak, K. L., Yaffe, K., Orwoll, E. S., Ix, J. H., You, Z., Barrett-Connor, E., Hoffman, A. R., Chonchol, M. 2018; 13 (3): 366–74

  Abstract

  Mild hyponatremia is a common finding in older adults; however, the association of lower serum sodium with cognition in older adults is currently unknown. We determined whether lower normal serum sodium is associated with cognitive impairment and risk of cognitive decline in community-dwelling older men.Five thousand four hundred thirty-five community-dwelling men aged ≥65 years who participated in Osteoporotic Fractures in Men, a cohort study with a median follow-up for cognitive function of 4.6 years, were included in this analysis. Multivariable logistic regression was used to examine the association between baseline fasting serum sodium levels and the odds of prevalent cognitive impairment (cross-sectional analysis; modified Mini-Mental Status [3MS] score <1.5 SD [<84] below or Trail Making Test Part B time >1.5 SD above the mean [>223 seconds]) and cognitive decline (prospective analysis [n=3611]; decrease in follow-up 3MS score or increase in Trails B time >1.5 SD of the mean score/time change [>9 or >67 seconds]).Participants were aged 74±6 years with a fasting mean serum sodium level of 141±3 mmol/L. Fifteen percent (n=274), 12% (n=225), and 13% (n=242) had prevalent cognitive impairment in tertiles 1, 2, and 3, respectively. After adjustment, lower serum sodium was associated with prevalent cognitive impairment (tertile 1 [126-140 mmol/L] versus tertile 2 [141-142 mmol/L], odds ratio [OR], 1.30; 95% confidence interval [95% CI], 1.06 to 1.61). Fourteen percent (n=159), 10% (n=125), and 13% (n=159) had cognitive decline in tertiles 1, 2, and 3, respectively. Lower serum sodium was also associated with cognitive decline (tertile 1 versus tertile 2, OR, 1.37; 95% CI, 1.06 to 1.77). Tertile 3 (143-153 mmol/L) was additionally associated with cognitive decline. Results were similar in sensitivity analyses according to clinical cut-offs and by quartiles.In community-dwelling older men, serum sodium between 126-140, and 126-140 or 143-153 mmol/L, are independently associated with prevalent cognitive impairment and cognitive decline, respectively.

  View details for DOI 10.2215/CJN.07400717

  View details for Web of Science ID 000427108100005

  View details for PubMedID 29439092

  View details for PubMedCentralID PMC5967671

• Genetic Determinants of Circulating Estrogen Levels and Evidence of a Causal Effect of Estradiol on Bone Density in Men JOURNAL OF CLINICAL ENDOCRINOLOGY & METABOLISM Eriksson, A. L., Perry, J. B., Coviello, A. D., Delgado, G. E., Ferrucci, L., Hoffman, A. R., Huhtaniemi, I. T., Ikram, M., Karlsson, M. K., Kleber, M. E., Laughlin, G. A., Liu, Y., Lorentzon, M., Lunetta, K. L., Mellstrom, D., Murabito, J. M., Murray, A., Nethander, M., Nielson, C. M., Prokopenko, I., Pye, S. R., Raffel, L. J., Rivadeneira, F., Srikanth, P., Stolk, L., Teumer, A., Travison, T. G., Uitterlinden, A. G., Vaidya, D., Vanderschueren, D., Zmuda, J. M., Maerz, W., Orwoll, E. S., Ouyang, P., Vandenput, L., Wu, F. W., de Jong, F. H., Bhasin, S., Kiel, D. P., Ohlsson, C. 2018; 103 (3): 991–1004

  Abstract

  Serum estradiol (E2) and estrone (E1) levels exhibit substantial heritability.To investigate the genetic regulation of serum E2 and E1 in men.Genome-wide association study in 11,097 men of European origin from nine epidemiological cohorts.Genetic determinants of serum E2 and E1 levels.Variants in/near CYP19A1 demonstrated the strongest evidence for association with E2, resolving to three independent signals. Two additional independent signals were found on the X chromosome; FAMily with sequence similarity 9, member B (FAM9B), rs5934505 (P = 3.4 × 10-8) and Xq27.3, rs5951794 (P = 3.1 × 10-10). E1 signals were found in CYP19A1 (rs2899472, P = 5.5 × 10-23), in Tripartite motif containing 4 (TRIM4; rs17277546, P = 5.8 × 10-14), and CYP11B1/B2 (rs10093796, P = 1.2 × 10-8). E2 signals in CYP19A1 and FAM9B were associated with bone mineral density (BMD). Mendelian randomization analysis suggested a causal effect of serum E2 on BMD in men. A 1 pg/mL genetically increased E2 was associated with a 0.048 standard deviation increase in lumbar spine BMD (P = 2.8 × 10-12). In men and women combined, CYP19A1 alleles associated with higher E2 levels were associated with lower degrees of insulin resistance.Our findings confirm that CYP19A1 is an important genetic regulator of E2 and E1 levels and strengthen the causal importance of E2 for bone health in men. We also report two independent loci on the X-chromosome for E2, and one locus each in TRIM4 and CYP11B1/B2, for E1.

  View details for DOI 10.1210/jc.2017-02060

  View details for Web of Science ID 000428808700021

  View details for PubMedID 29325096

  View details for PubMedCentralID PMC5868407

• Growth Hormone Research Society perspective on biomarkers of GH action in children and adults ENDOCRINE CONNECTIONS Johannsson, G., Bidlingmaier, M., Biller, B. K., Boguszewski, M., Casanueva, F. F., Chanson, P., Clayton, P. E., Choong, C. S., Clemmons, D., Dattani, M., Frystyk, J., Ho, K., Hoffman, A. R., Horikawa, R., Juul, A., Kopchick, J. J., Luo, X., Neggers, S., Netchine, I., Olsson, D. S., Radovick, S., Rosenfeld, R., Ross, R. J., Schilbach, K., Solberg, P., Strasburger, C., Trainer, P., Yuen, K. J., Wickstrom, K., Jorgensen, J. L., Growth Hormone Res Soc 2018; 7 (3): R126–R134

  Abstract

  The Growth Hormone Research Society (GRS) convened a Workshop in 2017 to evaluate clinical endpoints, surrogate endpoints and biomarkers during GH treatment of children and adults and in patients with acromegaly.GRS invited 34 international experts including clinicians, basic scientists, a regulatory scientist and physicians from the pharmaceutical industry.Current literature was reviewed and expert opinion was utilized to establish the state of the art and identify current gaps and unmet needs.Following plenary presentations, breakout groups discussed questions framed by the planning committee. The attendees re-convened after each breakout session to share the group reports. A writing team compiled the breakout session reports into a document that was subsequently discussed and revised by participants. This was edited further and circulated for final review after the meeting. Participants from pharmaceutical companies were not part of the writing process.The clinical endpoint in paediatric GH treatment is adult height with height velocity as a surrogate endpoint. Increased life expectancy is the ideal but unfeasible clinical endpoint of GH treatment in adult GH-deficient patients (GHDA) and in patients with acromegaly. The pragmatic clinical endpoints in GHDA include normalization of body composition and quality of life, whereas symptom relief and reversal of comorbidities are used in acromegaly. Serum IGF-I is widely used as a biomarker, even though it correlates weakly with clinical endpoints in GH treatment, whereas in acromegaly, normalization of IGF-I may be related to improvement in mortality. There is an unmet need for novel biomarkers that capture the pleiotropic actions of GH in relation to GH treatment and in patients with acromegaly.

  View details for DOI 10.1530/EC-18-0047

  View details for Web of Science ID 000434127900003

  View details for PubMedID 29483159

  View details for PubMedCentralID PMC5868631

• Vertebral Fracture Risk in Diabetic Elderly Men: The MrOS Study JOURNAL OF BONE AND MINERAL RESEARCH Napoli, N., Schwartz, A. V., Schafer, A. L., Vittinghoff, E., Cawthon, P. M., Parimi, N., Orwoll, E., Strotmeyer, E. S., Hoffman, A. R., Barrett-Connor, E., Black, D. M., Osteoporotic Fractures Men MrO 2018; 33 (1): 63–69

  Abstract

  Type 2 diabetes (T2DM) is associated with a significant increase in risk of nonvertebral fractures, but information on risk of vertebral fractures (VFs) in subjects with T2DM, particularly among men, is lacking. Furthermore, it is not known whether spine bone mineral density (BMD) can predict the risk of VF in T2DM. We sought to examine the effect of diabetes status on prevalent and incident vertebral fracture, and to estimate the effect of lumbar spine BMD (areal and volumetric) as a risk factor for prevalent and incident morphometric vertebral fracture in T2DM (n = 875) and nondiabetic men (n = 4679). We used data from the Osteoporotic Fractures in Men (MrOS) Study, which enrolled men aged ≥65 years. Lumbar spine areal BMD (aBMD) was measured with dual-energy X-ray absorptiometry (DXA), and volumetric BMD (vBMD) by quantitative computed tomography (QCT). Prevalence (7.0% versus 7.7%) and incidence (4.4% versus 4.5%) of VFs were not higher in T2DM versus nondiabetic men. The risk of prevalent (OR, 1.05; 95% CI, 0.78 to 1.40) or incident vertebral-fracture (OR, 1.28; 95% CI, 0.81 to 2.00) was not higher in T2DM versus nondiabetic men in models adjusted for age, clinic site, race, BMI, and aBMD. Higher spine aBMD was associated with lower risk of prevalent VF in T2DM (OR, 0.55; 95% CI, 0.48 to 0.63) and nondiabetic men (OR, 0.66; 95% CI, 0.5 to 0.88) (p for interaction = 0.24) and of incident VF in T2DM (OR, 0.50; 95% CI, 0.41 to 0.60) and nondiabetic men (OR, 0.54; 95% CI, 0.33 to 0.88) (p for interaction = 0.77). Results were similar for vBMD. In conclusion, T2DM was not associated with higher prevalent or incident VF in older men, even after adjustment for BMI and BMD. Higher spine aBMD and vBMD are associated with lower prevalence and incidence of VF in T2DM as well as nondiabetic men. © 2017 American Society for Bone and Mineral Research.

  View details for DOI 10.1002/jbmr.3287

  View details for Web of Science ID 000422723400010

  View details for PubMedID 28861910

• Trajectories of the relationships of physical activity with body composition changes in older men: the MrOS study. BMC geriatrics Laddu, D. R., Cawthon, P. M., Parimi, N., Hoffman, A. R., Orwoll, E., Miljkovic, I., Stefanick, M. L. 2017; 17 (1): 119-?

  Abstract

  Excess adiposity gains and significant lean mass loss may be risk factors for chronic disease in old age. Long-term patterns of change in physical activity (PA) and their influence on body composition decline during aging has not been characterized. We evaluated the interrelationships of PA and body composition at the outset and over longitudinal follow-up to changes in older men.Self-reported PA by the Physical Activity Scale for the Elderly (PASE), clinic body weight, and whole-body lean mass (LM) and fat mass, by dual-energy x-ray absorptiometry (DXA), were assessed in 5964 community-dwelling men aged ≥65 years at baseline (2000-2002) and at two subsequent clinic visits up until March 2009 (an average 4.6 and 6.9 years later). Group-based trajectory modeling (GBTM) identified patterns of change in PA and body composition variables. Relationships of PA and body composition changes were then assessed.GBTM identified three discrete trajectory patterns, all with declining PA, associated primarily with initial PA levelshigh-activity (7.2% of men), moderate-activity (50.0%), and low-activity (42.8%). In separate models, GBTM identified eight discrete total weight change groups, five fat mass change groups, and six LM change groups. Joint trajectory modeling by PA and body composition group illustrated significant declines in total weight and LM, whereas fat mass levels were relatively unchanged among high-activity and low-activity-declining groups, and significantly increased in the moderate-activity-declining group.Although patterns of change in PA and body composition were identified, groups were primarily differentiated by initial PA or body composition rather than by distinct trajectories of change in these variables.

  View details for DOI 10.1186/s12877-017-0506-4

  View details for PubMedID 28583069

• Low Testosterone, but Not Estradiol, Is Associated With Incident Falls in Older Men: The International MrOS Study JOURNAL OF BONE AND MINERAL RESEARCH Vandenput, L., Mellstrom, D., Laughlin, G. A., Cawthon, P. M., Cauley, J. A., Hoffman, A. R., Karlsson, M. K., Rosengren, B. E., Ljunggren, O., Nethander, M., Eriksson, A. L., Lorentzon, M., Leung, J., Kwok, T., Orwoll, E. S., Ohlsson, C. 2017; 32 (6): 1174–81

  Abstract

  Fracture risk is determined by bone strength and the risk of falls. The relationship between serum sex steroids and bone strength parameters in men is well known, whereas the predictive value of sex steroids for falls is less studied. The aim of this study was to assess the associations between serum testosterone (T) and estradiol (E2) and the likelihood of falls. Older men (aged ≥65 years) from the United States (n = 1919), Sweden (n = 2495), and Hong Kong (n = 1469) participating in the Osteoporotic Fractures in Men Study had baseline T and E2 analyzed by mass spectrometry. Bioavailable (Bio) levels were calculated using mass action equations. Incident falls were ascertained every 4 months during a mean follow-up of 5.7 years. Associations between sex steroids and falls were estimated by generalized estimating equations. Fall rate was highest in the US and lowest in Hong Kong (US 0.50, Sweden 0.31, Hong Kong 0.12 fall reports/person/year). In the combined cohort of 5883 men, total T (odds ratio [OR] per SD increase = 0.88, 95% confidence interval [CI] 0.86-0.91) and BioT (OR = 0.86, 95% CI 0.83-0.88) were associated with incident falls in models adjusted for age and prevalent falls. These associations were only slightly attenuated after simultaneous adjustment for physical performance variables (total T: OR = 0.94, 95% CI 0.91-0.96; BioT: OR = 0.91, 95% CI 0.89-0.94). E2, BioE2, and sex hormone-binding globulin (SHBG) were not significantly associated with falls. Analyses in the individual cohorts showed that both total T and BioT were associated with falls in MrOS US and Sweden. No association was found in MrOS Hong Kong, and this may be attributable to environmental factors rather than ethnic differences because total T and BioT predicted falls in MrOS US Asians. In conclusion, low total T and BioT levels, but not E2 or SHBG, are associated with increased falls in older men. © 2017 American Society for Bone and Mineral Research.

  View details for DOI 10.1002/jbmr.3088

  View details for Web of Science ID 000403220400005

  View details for PubMedID 28135013

  View details for PubMedCentralID PMC5466469

• Older Men with Anemia Have Increased Fracture Risk Independent of Bone Mineral Density. journal of clinical endocrinology and metabolism Valderrábano, R. J., Lee, J., Lui, L., Hoffman, A. R., Cummings, S. R., Orwoll, E. S., Wu, J. Y. 2017

  Abstract

  Extreme low hemoglobin values have been linked to increased risk of fracture at different sites in a small number of studies. However, careful assessment of a clinically relevant cutoff for anemia and cross sectional and longitudinal bone mineral density (BMD) measures is lacking.To determine whether men with anemia were at increased risk of fracture after accounting for bone density and bone loss.Cross-sectional analysis (at visit 3) and prospective analysis (from baseline to visit 3) in the Osteoporotic Fractures in Men (MrOS), a multi-site longitudinal cohort study.6 communities in the U.S.3632 community-dwelling men (>65 years) in MrOS at baseline (2000-2002) who were able to walk without assistance and did not have a hip replacement or fracture and had complete blood counts (CBCs) at visit 3 (2007-2009).Adjudicated spine and non-spine fractures during a median 7.2 years follow up.Analytic baseline characteristics associated with fractures or anemia (Hgb < 12g/dL) were included into multivariable models. Anemia was associated with increased risk of any (HR 1.67; 95% CI 1.26-2.21) and non-spine (HR 1.70; 95% CI 1.25-2.31) fractures. A model including change in BMD slightly attenuated the association with any (HR 1.60; 95% CI 1.20-2.13) and non-spine fractures (HR 1.57; 95% CI 1.14-2.15). Including absolute BMD did not significantly alter the anemia-fracture association. Anemia was not associated with spine fracture.Community-dwelling older men with anemia had a 57-72% increase in non-spine fracture risk independent of bone density and bone loss over time.

  View details for DOI 10.1210/jc.2017-00266

  View details for PubMedID 28368469

• The Limited Clinical Utility of Testosterone, Estradiol, and Sex Hormone Binding Globulin Measurements in the Prediction of Fracture Risk and Bone Loss in Older Men JOURNAL OF BONE AND MINERAL RESEARCH Orwoll, E. S., Lapidus, J., Wang, P. Y., Vandenput, L., Hoffman, A., Fink, H. A., Laughlin, G. A., Nethander, M., Ljunggren, O., Kindmark, A., Lorentzon, M., Karlsson, M. K., Mellstrom, D., Kwok, A., Khosla, S., Kwok, T., Ohlsson, C. 2017; 32 (3): 633-640

  View details for DOI 10.1002/jbmr.3021

  View details for Web of Science ID 000398055900023

• Daily Patterns of Accelerometer Activity Predict Changes in Sleep, Cognition, and Mortality in Older Men. journals of gerontology. Series A, Biological sciences and medical sciences Zeitzer, J. M., Blackwell, T., Hoffman, A. R., Cummings, S., Ancoli-Israel, S., Stone, K. 2017

  Abstract

  There is growing interest in the area of "wearable tech" and its relationship to health. A common element of many of these devices is a triaxial accelerometer that can yield continuous information on gross motor activity levels; how such data might predict changes in health is less clear.We examined accelerometry data from 2,976 older men who were part of the Osteoporotic Fractures in Men (MrOS) study. Using a shape-naive technique, functional principal component analysis, we examined the patterns of motor activity over the course of 4-7 days and determined whether these patterns were associated with changes in polysomnographic-determined sleep and cognitive function (Trail Making Test-Part B [Trails B], Modified Mini-Mental State Examination [3MS]), as well as mortality over 6.5-8 years of follow-up.In comparing baseline to 6.5 years later, multivariate modeling indicated that low daytime activity at baseline was associated with worsening of sleep efficiency (p < .05), more wake after sleep onset (p < .05), and a decrease in cognition (Trails B; p < .001), as well as a 1.6-fold higher rate of all-cause mortality (hazard ratio = 1.64 [1.34-2.00]). Earlier wake and bed times were associated with a decrease in cognition (3MS; p < .05). Having a late afternoon peak in activity was associated with a 1.4-fold higher rate of all-cause mortality (hazard ratio = 1.46 [1.21-1.77]). Those having a longer duration of their daytime activity with a bimodal activity pattern also had over a 1.4-fold higher rate of cardiovascular-related mortality (hazard ratio = 1.42 [1.02-1.98]).Patterns of daily activity may be useful as predictive biomarkers for changes in clinically relevant outcomes, including mortality and changes in sleep and cognition in older men.

  View details for DOI 10.1093/gerona/glw250

  View details for PubMedID 28158467

• When a gold standard isn't so golden: Lack of prediction of subjective sleep quality from sleep polysomnography. Biological psychology Kaplan, K. A., Hirshman, J., Hernandez, B., Stefanick, M. L., Hoffman, A. R., Redline, S., Ancoli-Israel, S., Stone, K., Friedman, L., Zeitzer, J. M. 2017; 123: 37-46

  Abstract

  Reports of subjective sleep quality are frequently collected in research and clinical practice. It is unclear, however, how well polysomnographic measures of sleep correlate with subjective reports of prior-night sleep quality in elderly men and women. Furthermore, the relative importance of various polysomnographic, demographic and clinical characteristics in predicting subjective sleep quality is not known. We sought to determine the correlates of subjective sleep quality in older adults using more recently developed machine learning algorithms that are suitable for selecting and ranking important variables.Community-dwelling older men (n=1024) and women (n=459), a subset of those participating in the Osteoporotic Fractures in Men study and the Study of Osteoporotic Fractures study, respectively, completed a single night of at-home polysomnographic recording of sleep followed by a set of morning questions concerning the prior night's sleep quality. Questionnaires concerning demographics and psychological characteristics were also collected prior to the overnight recording and entered into multivariable models. Two machine learning algorithms, lasso penalized regression and random forests, determined variable selection and the ordering of variable importance separately for men and women.Thirty-eight sleep, demographic and clinical correlates of sleep quality were considered. Together, these multivariable models explained only 11-17% of the variance in predicting subjective sleep quality. Objective sleep efficiency emerged as the strongest correlate of subjective sleep quality across all models, and across both sexes. Greater total sleep time and sleep stage transitions were also significant objective correlates of subjective sleep quality. The amount of slow wave sleep obtained was not determined to be important.Overall, the commonly obtained measures of polysomnographically-defined sleep contributed little to subjective ratings of prior-night sleep quality. Though they explained relatively little of the variance, sleep efficiency, total sleep time and sleep stage transitions were among the most important objective correlates.

  View details for DOI 10.1016/j.biopsycho.2016.11.010

  View details for PubMedID 27889439

  View details for PubMedCentralID PMC5292065

• Bone Density Loss Is Associated With Blood Cell Counts JOURNAL OF BONE AND MINERAL RESEARCH Valderrabano, R. J., Lui, L., Lee, J., Cummings, S. R., Orwoll, E. S., Hoffman, A. R., Wu, J. Y. 2017; 32 (2): 212-220

  Abstract

  Hematopoiesis depends on a supportive microenvironment. Preclinical studies in mice have demonstrated that osteoblasts influence the development of blood cells, particularly erythrocytes, B lymphocytes, and neutrophils. However, it is unknown whether osteoblast numbers or function impact blood cell counts in humans. We tested the hypothesis that men with low BMD or greater BMD loss have decreased circulating erythrocytes and lymphocytes and increased myeloid cells. We performed a cross-sectional analysis and prospective analysis in the Osteoporotic Fractures in Men (MrOS), a multi-site longitudinal cohort study. 2571 community-dwelling men (>65 years) who were able to walk without assistance, did not have a hip replacement or fracture and had complete blood counts (CBCs) at the third study visit were analyzed. Multivariable (MV)-adjusted logistic regression estimated odds of white blood cell subtypes (highest and lowest quintile vs middle), and anemia (clinically defined) associated with BMD by DXA scan (at visit 3), annualized percent BMD change (baseline to visit 3), and high BMD loss (>0.5%/year, from baseline to visit 3) at the femoral neck (FN) and total hip (TH). MV adjusted models included age, BMI, cancer history, smoking status, alcohol intake, corticosteroid use, self-reported health, thiazide use and physical activity. At visit 3 greater TH BMD loss (per standard deviation) was associated with increased odds of anemia, high neutrophils, and low lymphocytes. Annualized BMD loss of >0.5% was associated with increased odds of anemia, high neutrophils, and low lymphocytes. Similar results were observed for FN BMD regarding anemia and lymphocytes. We concluded that community-dwelling older men with declining hip BMD over about 7 years had increased risks of anemia, lower lymphocyte count, and higher neutrophil count, consistent with pre-clinical studies. Bone health and hematopoiesis may have greater interdependency than previously recognized. This article is protected by copyright. All rights reserved.

  View details for DOI 10.1002/jbmr.3000

  View details for Web of Science ID 000396935300004

• Mitochondrial DNA Hypomethylation Is a Biomarker Associated with Induced Senescence in Human Fetal Heart Mesenchymal Stem Cells STEM CELLS INTERNATIONAL Yu, D., Du, Z., Pian, L., Li, T., Wen, X., Li, W., Kim, S., Xiao, J., Cohen, P., Cui, J., Hoffman, A. R., Hu, J. 2017

  Abstract

  Background. Fetal heart can regenerate to restore its normal anatomy and function in response to injury, but this regenerative capacity is lost within the first week of postnatal life. Although the specific molecular mechanisms remain to be defined, it is presumed that aging of cardiac stem or progenitor cells may contribute to the loss of regenerative potential. Methods. To study this aging-related dysfunction, we cultured mesenchymal stem cells (MSCs) from human fetal heart tissues. Senescence was induced by exposing cells to chronic oxidative stress/low serum. Mitochondrial DNA methylation was examined during the period of senescence. Results. Senescent MSCs exhibited flattened and enlarged morphology and were positive for the senescence-associated beta-galactosidase (SA-β-Gal). By scanning the entire mitochondrial genome, we found that four CpG islands were hypomethylated in close association with senescence in MSCs. The mitochondrial COX1 gene, which encodes the main subunit of the cytochrome c oxidase complex and contains the differentially methylated CpG island 4, was upregulated in MSCs in parallel with the onset of senescence. Knockdown of DNA methyltransferases (DNMT1, DNMT3a, and DNMT3B) also upregulated COX1 expression and induced cellular senescence in MSCs. Conclusions. This study demonstrates that mitochondrial CpG hypomethylation may serve as a critical biomarker associated with cellular senescence induced by chronic oxidative stress.

  View details for DOI 10.1155/2017/1764549

  View details for Web of Science ID 000398317400001

  View details for PubMedID 28484495

• Risk Factors for Hip Fracture in Older Men: The Osteoporotic Fractures in Men Study (MrOS). Journal of bone and mineral research Cauley, J. A., Cawthon, P. M., Peters, K. E., Cummings, S. R., Ensrud, K. E., Bauer, D. C., Taylor, B. C., Shikany, J. M., Hoffman, A. R., Lane, N. E., Kado, D. M., Stefanick, M. L., Orwoll, E. S. 2016; 31 (10): 1810-1819

  Abstract

  Almost 30% of hip fractures occur in men; the mortality, morbidity, and loss of independence after hip fractures are greater in men than in women. To comprehensively evaluate risk factors for hip fracture in older men, we performed a prospective study of 5994 men, primarily white, age 65+ years recruited at six US clinical centers. During a mean of 8.6 years of 97% complete follow-up, 178 men experienced incident hip fractures. Information on risk factors including femoral neck bone mineral density (FNBMD) was obtained at the baseline visit. Cox proportional hazards models were used to calculate the hazard ratio (HR) with 95% confidence intervals; Fine and Gray models adjusted for competing mortality risk. Older age (≥75 years), low FNBMD, currently smoking, greater height and height loss since age 25 years, history of fracture, use of tricyclic antidepressants, history of myocardial infarction or angina, hyperthyroidism or Parkinson's disease, lower protein intake, and lower executive function were all associated with an increased hip fracture risk. Further adjustment for competing mortality attenuated HR for smoking, hyperthyroidism, and Parkinson's disease. The incidence rate of hip fracture per 1000 person-years (PY) was greatest in men with FNBMD T-scores <-2.5 (white women reference database) who also had 4+ risk factors, 33.4. Men age ≥80 years with 3+ major comorbidities experienced hip fracture at rates of 14.52 versus 0.88 per 1000 PY in men age <70 years with zero comorbidities. Older men with low FNBMD, multiple risk factors, and multimorbidity have a high risk of hip fracture. Many of these assessments can easily be incorporated into routine clinical practice and may lead to improved risk stratification. © 2016 American Society for Bone and Mineral Research.

  View details for DOI 10.1002/jbmr.2836

  View details for PubMedID 26988112

  View details for PubMedCentralID PMC5240502

• AMERICAN ASSOCIATION OF CLINICAL ENDOCRINOLOGISTS AND AMERICAN COLLEGE OF ENDOCRINOLOGY DISEASE STATE CLINICAL REVIEW: UPDATE ON GROWTH HORMONE STIMULATION TESTING AND PROPOSED REVISED CUT-POINT FOR THE GLUCAGON STIMULATION TEST IN THE DIAGNOSIS OF ADULT GROWTH HORMONE DEFICIENCY ENDOCRINE PRACTICE Yuen, K. C., Tritos, N. A., Samson, S. L., Hoffman, A. R., Katznelson, L. 2016; 22 (10): 1235-1244

  Abstract

  The clinical features of adult GH deficiency (GHD) are nonspecific, and GH stimulation testing is often required to confirm the diagnosis. However, diagnosing adult GHD can be challenging due to the episodic and pulsatile GH secretion, concurrently modified by age, gender, and body mass index (BMI).PubMed searches were conducted to identify published data since 2009 on GH stimulation tests used to diagnose adult GHD. Relevant articles in English language were identified and considered for inclusion in the present document.Testing for confirmation of adult GHD should only be considered if there is a high pretest probability, and the intent to treat if the diagnosis is confirmed. The insulin tolerance test (ITT) and glucagon stimulation test (GST) are the two main tests used in the United States. While the ITT has been accepted as the gold-standard test, its safety concerns hamper wider use. Previously, the GH-releasing hormone-arginine test, and more recently the GST, are accepted alternatives to the ITT. However, several recent studies have questioned the diagnostic accuracy of the GST when the GH cut-point of 3 μg/L is used and have suggested that a lower GH cut-point of 1 μg/L improved the sensitivity and specificity of this test in overweight/obese patients and in those with glucose intolerance.Until a potent, safe, and reliable test becomes available, the GST should remain as the alternative to the ITT in the United States. In order to reduce over-diagnosing adult GHD in overweight/obese patients with the GST, we propose utilizing a lower GH cut-point of 1 μg/L in these subjects. However, this lower GH cut-point still needs further evaluation for diagnostic accuracy in larger patient populations with varying BMIs and degrees of glucose tolerance.AACE = American Association of Clinical Endocrinologists BMI = body mass index GH = growth hormone GHD = GH deficiency GHRH = GH-releasing hormone GHS = GH secretagogue GST = glucagon stimulation test IGF = insulin-like growth factor IGFBP-3 = IGF-binding protein 3 ITT = insulin tolerance test ROC = receiver operating characteristic WB-GST = weight-based GST.

  View details for DOI 10.4158/EP161407.DSCR

  View details for Web of Science ID 000389842700012

  View details for PubMedID 27409821

• Bone Density Loss Is Associated With Blood Cell Counts. Journal of bone and mineral research Valderrábano, R. J., Lui, L., Lee, J., Cummings, S. R., Orwoll, E. S., Hoffman, A. R., Wu, J. Y. 2016

  Abstract

  Hematopoiesis depends on a supportive microenvironment. Preclinical studies in mice have demonstrated that osteoblasts influence the development of blood cells, particularly erythrocytes, B lymphocytes, and neutrophils. However, it is unknown whether osteoblast numbers or function impact blood cell counts in humans. We tested the hypothesis that men with low BMD or greater BMD loss have decreased circulating erythrocytes and lymphocytes and increased myeloid cells. We performed a cross-sectional analysis and prospective analysis in the Osteoporotic Fractures in Men (MrOS), a multi-site longitudinal cohort study. 2571 community-dwelling men (>65 years) who were able to walk without assistance, did not have a hip replacement or fracture and had complete blood counts (CBCs) at the third study visit were analyzed. Multivariable (MV)-adjusted logistic regression estimated odds of white blood cell subtypes (highest and lowest quintile vs middle), and anemia (clinically defined) associated with BMD by DXA scan (at visit 3), annualized percent BMD change (baseline to visit 3), and high BMD loss (>0.5%/year, from baseline to visit 3) at the femoral neck (FN) and total hip (TH). MV adjusted models included age, BMI, cancer history, smoking status, alcohol intake, corticosteroid use, self-reported health, thiazide use and physical activity. At visit 3 greater TH BMD loss (per standard deviation) was associated with increased odds of anemia, high neutrophils, and low lymphocytes. Annualized BMD loss of >0.5% was associated with increased odds of anemia, high neutrophils, and low lymphocytes. Similar results were observed for FN BMD regarding anemia and lymphocytes. We concluded that community-dwelling older men with declining hip BMD over about 7 years had increased risks of anemia, lower lymphocyte count, and higher neutrophil count, consistent with pre-clinical studies. Bone health and hematopoiesis may have greater interdependency than previously recognized. This article is protected by copyright. All rights reserved.

  View details for DOI 10.1002/jbmr.3000

  View details for PubMedID 27653240

• Serum 25-hydroxyvitamin D level and incident type 2 diabetes in older men, the Osteoporotic Fractures in Men (MrOS) study BONE Napoli, N., Schafer, A. L., Lui, L., Cauley, J. A., Strotmeyer, E. S., Le Blanc, E. S., Hoffman, A. R., Lee, C. G., Black, D. M., Schwartz, A. V. 2016; 90: 181-184

  Abstract

  The association between vitamin D status and diabetes risk is inconsistent among observational studies, and most of the available studies have been with women. In the present study we investigated the association between serum 25-hydroxyvitamin D (25(OH)D) levels and incident type 2 diabetes (T2D) in older men (≥65years old) who participated in the multisite Osteoporotic Fractures in Men (MrOS) study enrolled from March 2000 to April 2002. Baseline 25(OH)D levels were available in 1939 subjects without prevalent T2D. Clinical information, body mass index (BMI) and other factors related to T2D were assessed at the baseline visit. Incident diabetes, defined by self-report and medication use, was determined over an average follow-up of 6.4years. At baseline, participants were, on average, 73.3 (±5.7) years old, had a mean BMI in the overweight range (27.2kg/m(2)±3.6) and had total serum 25(OH)D of 26.1ng/ml (±8.3). Incident diabetes was diagnosed in 139 subjects. Cox regression analysis showed a trend toward a protective effect of higher 25(OH)D levels with a lower risk of T2D (HR 0.87, 95% CI: 0.73-1.04 per 1 SD increase of 25(OH)D). After adjusted for BMI and other potential confounders, the relationship between 25(OH)D levels and incident diabetes was further attenuated (HR 1.03, 95% CI 0.85-1.25). No significant difference in the incidence of diabetes emerged after analyzing study subjects according to baseline 25(OH)D quartiles. In conclusion, 25(OH)D levels were not associated with incident T2D in older men.

  View details for DOI 10.1016/j.bone.2016.07.001

  View details for Web of Science ID 000381246600022

  View details for PubMedID 27393241

• Thyroid Function Variations Within the Reference Range Do Not Affect Quality of Life, Mood, or Cognitive Function in Community-Dwelling Older Men. Thyroid Samuels, M. H., Kaimal, R., Waring, A., Fink, H. A., Yaffe, K., Hoffman, A. R., Orwoll, E., Bauer, D. 2016; 26 (9): 1185-1194

  Abstract

  Variations in thyroid function within the laboratory reference range have been associated with a number of clinical outcomes. However, quality of life, mood, and cognitive function have not been extensively studied, and it is not clear whether mild variations in thyroid function have major effects on these neurocognitive outcomes.Data were analyzed from the Osteoporotic Fractures in Men (MrOS) Study, a cohort of community-dwelling men aged 65 years and older in the United States. A total of 539 participants who were not taking thyroid medications and had age-adjusted TSH levels within the reference range underwent detailed testing of quality of life, mood, and cognitive function at baseline. The same quality of life, mood, and cognitive outcomes were measured again in 193 of the men after a mean follow-up of 6 years. Outcomes were analyzed using thyrotropin (TSH) and free thyroxine (FT4) levels as continuous independent variables, adjusting for relevant covariates.At baseline, there were no associations between TSH or FT4 levels and measures of quality of life, mood, or cognition in the 539 euthyroid men. Baseline thyroid function did not predict changes in these outcomes over a mean of 6 years in the 193 men in the longitudinal analysis.Variations in thyroid function within the age-adjusted laboratory reference range are not associated with variations in quality of life, mood, or cognitive function in community-dwelling older men.

  View details for DOI 10.1089/thy.2016.0104

  View details for PubMedID 27484219

• Growth Hormone Research Society perspective on the development of long-acting growth hormone preparations EUROPEAN JOURNAL OF ENDOCRINOLOGY Christiansen, J. S., Backeljauw, P. F., Bidlingmaier, M., Biller, B. M., Boguszewski, M. C., Casanueva, F. F., Chanson, P., Chatelain, P., Choong, C. S., Clemmons, D. R., Cohen, L. E., Cohen, P., Frystyk, J., Grimberg, A., Hasegawa, Y., Haymond, M. W., Ho, K., Hoffman, A. R., Holly, J. M., Horikawa, R., Hoeybye, C., Jorgensen, J. O., Johannsson, G., Juul, A., Katznelson, L., Kopchick, J. J., Lee, K. O., Lee, K., Luo, X., Melmed, S., Miller, B. S., Misra, M., Popovic, V., Rosenfeld, R. G., Ross, J., Ross, R. J., Saenger, P., Strasburger, C. J., Thorner, M. O., Werner, H., Yuen, K. 2016; 174 (6): C1-C8

  Abstract

  The Growth Hormone (GH) Research Society (GRS) convened a workshop to address important issues regarding trial design, efficacy, and safety of long-acting growth hormone preparations (LAGH).A closed meeting of 55 international scientists with expertise in GH, including pediatric and adult endocrinologists, basic scientists, regulatory scientists, and participants from the pharmaceutical industry.Current literature was reviewed for gaps in knowledge. Expert opinion was used to suggest studies required to address potential safety and efficacy issues.Following plenary presentations summarizing the literature, breakout groups discussed questions framed by the planning committee. Attendees reconvened after each breakout session to share group reports. A writing team compiled the breakout session reports into a draft document that was discussed and revised in an open forum on the concluding day. This was edited further and then circulated to attendees from academic institutions for review after the meeting. Participants from pharmaceutical companies did not participate in the planning, writing, or in the discussions and text revision on the final day of the workshop. Scientists from industry and regulatory agencies reviewed the manuscript to identify any factual errors.LAGH compounds may represent an advance over daily GH injections because of increased convenience and differing phamacodynamic properties, providing the potential for improved adherence and outcomes. Better methods to assess adherence must be developed and validated. Long-term surveillance registries that include assessment of efficacy, cost-benefit, disease burden, quality of life, and safety are essential for understanding the impact of sustained exposure to LAGH preparations.

  View details for DOI 10.1530/EJE-16-0111

  View details for Web of Science ID 000377114700001

  View details for PubMedID 27009113

• Sleep Disordered Breathing and Risk of Stroke in Older Community-Dwelling Men SLEEP Stone, K. L., Blackwell, T. L., Ancoli-Israel, S., Barrett-Connor, E., Bauer, D. C., Cauley, J. A., Ensrud, K. E., Hoffman, A. R., Mehra, R., Stefanick, M. L., Varosy, P. D., Yaffe, K., Redline, S. 2016; 39 (3): 531-540

  Abstract

  Men with sleep disordered breathing (SDB) may be at increased stroke risk, due to nocturnal hypoxemia, sleep loss or fragmentation, or other mechanisms. We examined the association of SDB with risk of incident stroke in a large cohort of older men.Participants were 2,872 community-dwelling men (mean age 76 years) enrolled in the MrOS Sleep Study, which gathered data from 2003 to 2005 at six clinical sites in the Unites States. SDB predictors (obstructive apnea-hypopnea index, apnea-hypopnea index, central apnea index, and nocturnal hypoxemia) were measured using overnight polysomnography. Incident stroke over an average follow-up of 7.3 years was centrally adjudicated by physician review of medical records.One hundred fifty-six men (5.4%) had a stroke during follow-up. After adjustment for age, clinic site, race, body mass index, and smoking status, older men with severe nocturnal hypoxemia (≥ 10% of the night with SpO2 levels below 90%) had a 1.8-fold increased risk of incident stroke compared to those without nocturnal hypoxemia (relative hazard = 1.83; 95% confidence interval 1.12-2.98; P trend = 0.02). Results were similar after further adjustment for other potential covariates and after excluding men with a history of stroke. Other indices of SDB were not associated with incident stroke.Older men with severe nocturnal hypoxemia are at significantly increased risk of incident stroke. Measures of overnight oxygen saturation may better identify older men at risk for stroke than measures of apnea frequency.

  View details for DOI 10.5665/sleep.5520

  View details for Web of Science ID 000371115800007

  View details for PubMedID 26943468

  View details for PubMedCentralID PMC4763364

• Converting Skin Fibroblasts into Hepatic-like Cells by Transient Programming. Journal of cellular biochemistry Zhu, X., Pan, X., Yao, L., Li, W., Cui, J., Wang, G., Mrsny, R. J., Hoffman, A. R., Hu, J. 2016; 117 (3): 589-598

  Abstract

  Transplantation of hepatocytes is a promising therapy for end-stage liver disease, but the availability of functional cells currently precludes its clinical application. We now report a simple transient reprogramming approach to convert fibroblasts into hepatic-like cells. Human skin fibroblasts were treated with fish egg extracts to become the transiently remodeled cells (TRCs). After infected with retroviral EGFP, they were directly injected into the fetal monkey liver, where they underwent in situ differentiation in the hepatic niche. The hepatic-like cells were functional as shown by the synthesis of hepatic markers in vivo, including albumin, cytokeratin-18, and hepatic serum antigen. Similarly, when implanted in the mouse liver, the TRCs were differentiated into hepatic-like cells that synthesize albumin and CK18 and became completely integrated into the liver parenchyma. The potency of TRCs was mechanistically related to the activation of several signal pathways, which reactivate endogenous genes related to cell potency. This study demonstrates the feasibility of a simple and inexpensive epigenetic remodeling approach to convert human fibroblasts into therapeutic hepatic-like cells for the treatment of end-stage liver disease.

  View details for DOI 10.1002/jcb.25355

  View details for PubMedID 26312781

• Sex hormones, sex hormone binding globulin, and vertebral fractures in older men BONE Cawthon, P. M., Schousboe, J. T., Harrison, S. L., Ensrud, K. E., Black, D., Cauley, J. A., Cummings, S. R., LeBlanc, E. S., Laughlin, G. A., Nielson, C. M., Broughton, A., Kado, D. M., Hoffman, A. R., Jamal, S. A., Barrett-Connor, E., Orwoll, E. S. 2016; 84: 271-278

  Abstract

  The association between sex hormones and sex hormone binding globin (SHBG) with vertebral fractures in men is not well studied. In these analyses, we determined whether sex hormones and SHBG were associated with greater likelihood of vertebral fractures in a prospective cohort study of community dwelling older men. We included data from participants in MrOS who had been randomly selected for hormone measurement (N=1463, including 1054 with follow-up data 4.6years later). Major outcomes included prevalent vertebral fracture (semi-quantitative grade≥2, N=140, 9.6%) and new or worsening vertebral fracture (change in SQ grade≥1, N=55, 5.2%). Odds ratios per SD decrease in sex hormones and per SD increase in SHBG were estimated with logistic regression adjusted for potentially confounding factors, including age, bone mineral density, and other sex hormones. Higher SHBG was associated with a greater likelihood of prevalent vertebral fractures (OR: 1.38 per SD increase, 95% CI: 1.11, 1.72). Total estradiol analyzed as a continuous variable was not associated with prevalent vertebral fractures (OR per SD decrease: 0.86, 95% CI: 0.68 to 1.10). Men with total estradiol values ≤17pg/ml had a borderline higher likelihood of prevalent fracture than men with higher values (OR: 1.46, 95% CI: 0.99, 2.16). There was no association between total testosterone and prevalent fracture. In longitudinal analyses, SHBG (OR: 1.42 per SD increase, 95% CI: 1.03, 1.95) was associated with new or worsening vertebral fracture, but there was no association with total estradiol or total testosterone. In conclusion, higher SHBG (but not testosterone or estradiol) is an independent risk factor for vertebral fractures in older men.

  View details for DOI 10.1016/j.bone.2016.01.009

  View details for Web of Science ID 000370914600032

  View details for PubMedID 26778261

• GH safety workshop position paper: a critical appraisal of recombinant human GH therapy in children and adults EUROPEAN JOURNAL OF ENDOCRINOLOGY Allen, D. B., Backeljauw, P., Bidlingmaier, M., Biller, B. M., Boguszewski, M., Burman, P., Butler, G., Chihara, K., Christiansen, J., Cianfarani, S., Clayton, P., Clemmons, D., Cohen, P., Darendeliler, F., Deal, C., Dunger, D., Erfurth, E. M., Fuqua, J. S., Grimberg, A., Haymond, M., Higham, C., Ho, K., Hoffman, A. R., Hokken-Koelega, A., Johannsson, G., Juul, A., Kopchick, J., Lee, P., Pollak, M., Radovick, S., Robison, L., Rosenfeld, R., Ross, R. J., Savendahl, L., Saenger, P., Sorensen, H. T., Stochholm, K., Strasburger, C., Swerdlow, A., Thorner, M. 2016; 174 (2): P1-P9

  Abstract

  Recombinant human GH (rhGH) has been in use for 30 years, and over that time its safety and efficacy in children and adults has been subject to considerable scrutiny. In 2001, a statement from the GH Research Society (GRS) concluded that 'for approved indications, GH is safe'; however, the statement highlighted a number of areas for on-going surveillance of long-term safety, including cancer risk, impact on glucose homeostasis, and use of high dose pharmacological rhGH treatment. Over the intervening years, there have been a number of publications addressing the safety of rhGH with regard to mortality, cancer and cardiovascular risk, and the need for long-term surveillance of the increasing number of adults who were treated with rhGH in childhood. Against this backdrop of interest in safety, the European Society of Paediatric Endocrinology (ESPE), the GRS, and the Pediatric Endocrine Society (PES) convened a meeting to reappraise the safety of rhGH. The ouput of the meeting is a concise position statement.

  View details for DOI 10.1530/EJE-15-0873

  View details for Web of Science ID 000370244100001

  View details for PubMedCentralID PMC4674592

• Subclinical Thyroid Dysfunction and Frailty Among Older Men JOURNAL OF CLINICAL ENDOCRINOLOGY & METABOLISM Virgini, V. S., Rodondi, N., Cawthon, P. M., Harrison, S. L., Hoffman, A. R., Orwoll, E. S., Ensrud, K. E., Bauer, D. C. 2015; 100 (12): 4524-4532

  View details for DOI 10.1210/jc.2015-3191

  View details for Web of Science ID 000368428600033

• Evaluation of the Usefulness of Consensus Definitions of Sarcopenia in Older Men: Results from the Observational Osteoporotic Fractures in Men Cohort Study JOURNAL OF THE AMERICAN GERIATRICS SOCIETY Cawthon, P. M., Blackwell, T. L., Cauley, J., Kado, D. M., Barrett-Connor, E., Lee, C. G., Hoffman, A. R., Nevitt, M., Stefanick, M. L., Lane, N. E., Ensrud, K. E., Cummings, S. R., Orwoll, E. S. 2015; 63 (11): 2247-2259

  Abstract

  To evaluate the associations between definitions of sarcopenia and clinical outcomes and the ability of the definitions to discriminate those with a high likelihood of having these outcomes from those with a low likelihood.Osteoporotic Fractures in Men Study.Six clinical centers.Community-dwelling men aged 65 and older (N = 5,934).Sarcopenia definitions from the International Working Group, European Working Group on Sarcopenia in Older Persons, Foundation for the National Institutes of Health Sarcopenia Project, Baumgartner, and Newman were evaluated. Recurrent falls were defined as two or more self-reported falls in the year after baseline (n = 694, 11.9%). Incident hip fractures (n = 207, 3.5%) and deaths (n = 2,003, 34.1%) were confirmed according to central review of medical records over 9.8 years. Self-reported functional limitations were assessed at baseline and 4.6 years later. Logistic regression or proportional hazards models were used to estimate associations between sarcopenia and falls, hip fractures, and death. The discriminative ability of the sarcopenia definitions (vs reference models) for these outcomes was evaluated using area under the receiver operating characteristic curve or C-statistics. Referent models included age alone for falls, functional limitations and mortality, and age and bone mineral density for hip fractures.The association between sarcopenia according to the various definitions and risk of falls, functional limitations, and hip fractures was variable; all definitions were associated with greater risk of death, but none of the definitions materially changed discrimination based on the AUC and C-statistic when compared with reference models (change ≤1% in all models).Sarcopenia definitions as currently constructed did not consistently improve prediction of clinical outcomes in relatively healthy older men.

  View details for DOI 10.1111/jgs.13788

  View details for Web of Science ID 000365678500002

  View details for PubMedID 26502831

  View details for PubMedCentralID PMC4739621

• Restoration of IGF2 imprinting by polycomb repressive complex 2 docking factor SUZ12 in colon cancer cells EXPERIMENTAL CELL RESEARCH Wang, H., Ge, S., Qian, G., Li, W., Cui, J., Wang, G., Hoffman, A. R., Hu, J. 2015; 338 (2): 214-221

  View details for DOI 10.1016/j.yexcr.2015.09.016

  View details for Web of Science ID 000364354500009

  View details for PubMedID 26407907

• A Novel Inherited Mutation in PRKAR1A Abrogates PreRNA Splicing in a Carney Complex Family CANADIAN JOURNAL OF CARDIOLOGY Sun, Y., Chen, X., Sun, J., Wen, X., Liu, X., Zhang, Y., Hoffman, A. R., Hu, J., Gao, Y. 2015; 31 (11): 1393-1401

  View details for DOI 10.1016/j.cjca.2015.05.018

  View details for Web of Science ID 000365334100010

  View details for PubMedID 26416542

• Status of long-acting-growth hormone preparations-2015 GROWTH HORMONE & IGF RESEARCH Hoybye, C., Cohen, P., Hoffman, A. R., Ross, R., Biller, B. M., Christiansen, J. S. 2015; 25 (5): 201-206

  View details for DOI 10.1016/j.ghir.2015.07.004

  View details for Web of Science ID 000362139000001

  View details for PubMedID 26187188

• Greater Skeletal Muscle Fat Infiltration Is Associated With Higher All-Cause and Cardiovascular Mortality in Older Men JOURNALS OF GERONTOLOGY SERIES A-BIOLOGICAL SCIENCES AND MEDICAL SCIENCES Miljkovic, I., Kuipers, A. L., Cauley, J. A., Prasad, T., Lee, C. G., Ensrud, K. E., Cawthon, P. M., Hoffman, A. R., Dam, T., Gordon, C. L., Zmuda, J. M. 2015; 70 (9): 1133-1140

  Abstract

  Skeletal muscle fat infiltration (myosteatosis) increases with aging, and has been associated with poor metabolic and musculoskeletal health, independent of overall adiposity. Studies examining the relationship of myosteatosis and mortality among older individuals recruited without regard to their health status are sparse.We evaluated the association of peripheral computed tomography measured calf myosteatosis (intermuscular fat and muscle density as a measure of intramuscular fat) with mortality in 1,063 community-dwelling older men. Cox proportional hazards models were used to estimate the risk of mortality independent of potential confounders.During a mean follow-up of 7.2 years, 317 participants died. After adjustment for potential covariates and additional adjustment for whole body fat, lower skeletal muscle density was associated with increased all-cause mortality and cardiovascular disease mortality (hazard ratio [95% confidence interval] per standard deviation lower skeletal muscle density: 1.24 [1.09-1.41] and 1.46 [1.15-1.86], respectively), and to some extent with noncardiovascular disease mortality (1.18 [1.0-1.38], p = .053). After adjusting for trunk fat in a separate multivariable model, the association between skeletal muscle density and all-cause and cardiovascular disease mortality remained significant (both p < .01), while its association with noncardiovascular disease mortality became of borderline significance (p = .085). No other measures of adiposity, including calf intermuscular fat, were associated with mortality.Our study reveals an independent association between skeletal muscle density and mortality in a community-based sample of older, predominantly Caucasian men. Further studies are needed to establish if this association is independent of other ectopic fat depots, and to identify the biological mechanisms underlying this relationship.

  View details for DOI 10.1093/gerona/glv027

  View details for Web of Science ID 000363482300012

  View details for PubMedID 25838547

  View details for PubMedCentralID PMC4553718

• Six Degree-of-Freedom Measurements of Human Mild Traumatic Brain Injury ANNALS OF BIOMEDICAL ENGINEERING Hernandez, F., Wu, L. C., Yip, M. C., Laksari, K., Hoffman, A. R., Lopez, J. R., Grant, G. A., Kleiven, S., Camarillo, D. B. 2015; 43 (8): 1918-1934

  Abstract

  This preliminary study investigated whether direct measurement of head rotation improves prediction of mild traumatic brain injury (mTBI). Although many studies have implicated rotation as a primary cause of mTBI, regulatory safety standards use 3 degree-of-freedom (3DOF) translation-only kinematic criteria to predict injury. Direct 6DOF measurements of human head rotation (3DOF) and translation (3DOF) have not been previously available to examine whether additional DOFs improve injury prediction. We measured head impacts in American football, boxing, and mixed martial arts using 6DOF instrumented mouthguards, and predicted clinician-diagnosed injury using 12 existing kinematic criteria and 6 existing brain finite element (FE) criteria. Among 513 measured impacts were the first two 6DOF measurements of clinically diagnosed mTBI. For this dataset, 6DOF criteria were the most predictive of injury, more than 3DOF translation-only and 3DOF rotation-only criteria. Peak principal strain in the corpus callosum, a 6DOF FE criteria, was the strongest predictor, followed by two criteria that included rotation measurements, peak rotational acceleration magnitude and Head Impact Power (HIP). These results suggest head rotation measurements may improve injury prediction. However, more 6DOF data is needed to confirm this evaluation of existing injury criteria, and to develop new criteria that considers directional sensitivity to injury.

  View details for DOI 10.1007/s10439-014-1212-4

  View details for Web of Science ID 000358249800018

  View details for PubMedCentralID PMC4478276

• Long non-coding RNA ROR decoys gene-specific histone methylation to promote tumorigenesis GENOME BIOLOGY Fan, J., Xing, Y., Wen, X., Jia, R., Ni, H., He, J., Ding, X., Pan, H., Qian, G., Ge, S., Hoffman, A. R., Zhang, H., Fan, X. 2015; 16

  Abstract

  Long non-coding RNAs (lncRNAs) are not translated into proteins and were initially considered to be part of the 'dark matter' of the genome. Recently, it has been shown that lncRNAs play a role in the recruitment of chromatin modifying complexes and can influence gene expression. However, it is unknown if lncRNAs function in a similar way in cancer.Here, we show that the lncRNA ROR occupies and activates the TESC promoter by repelling the histone G9A methyltransferase and promoting the release of histone H3K9 methylation. Suppression of ROR in tumors results in silencing of TESC expression, and G9A-mediated histone H3K9 methylation in the TESC promoter is restored, which significantly reduces tumor growth and metastasis. Without ROR silencing, TESC knockdown presents consistent and significant reductions in tumor progression.Our results reveal a novel mechanism by which ROR may serve as a decoy oncoRNA that blocks binding surfaces, preventing the recruitment of histone modifying enzymes, thereby specifying a new pattern of histone modifications that promote tumorigenesis.

  View details for DOI 10.1186/s13059-015-0705-2

  View details for Web of Science ID 000357924000001

  View details for PubMedID 26169368

  View details for PubMedCentralID PMC4499915

• AMERICAN ASSOCIATION OF CLINICAL ENDOCRINOLOGISTS AND AMERICAN COLLEGE OF ENDOCRINOLOGY DISEASE STATE CLINICAL REVIEW: MANAGEMENT OF ACROMEGALY PATIENTS: MANAGEMENT OF ACROMEGALY PATIENTS: WHAT IS THE ROLE OF PRE-OPERATIVE MEDICAL THERAPY? ENDOCRINE PRACTICE Fleseriu, M., Hoffman, A. R., Katznelson, L. 2015; 21 (6): 668-673

  View details for DOI 10.4158/EP14575.DSCR

  View details for Web of Science ID 000357732000013

• Identifying multi-locus chromatin contacts in human cells using tethered multiple 3C BMC GENOMICS Ay, F., Vu, T. H., Zeitz, M. J., Varoquaux, N., Carette, J. E., Vert, J., Hoffman, A. R., Noble, W. S. 2015; 16

  View details for DOI 10.1186/s12864-015-1236-7

  View details for Web of Science ID 000351261400001

• Aberrant allele-switch imprinting of a novel IGF1R intragenic antisense non-coding RNA in breast cancers EUROPEAN JOURNAL OF CANCER Kang, L., Sun, J., Wen, X., Cui, J., Wang, G., Hoffman, A. R., Hu, J., Li, W. 2015; 51 (2): 260-270

  Abstract

  The insulin-like growth factor type I receptor (IGF1R) is frequently dysregulated in breast cancers, yet the molecular mechanisms are unknown. A novel intragenic long non-coding RNA (lncRNA) IRAIN within the IGF1R locus has been recently identified in haematopoietic malignancies using RNA-guided chromatin conformation capture (R3C). In breast cancer tissues, we found that IRAIN lncRNA was transcribed from an intronic promoter in an antisense direction as compared to the IGF1R coding mRNA. Unlike the IGF1R coding RNA, this non-coding RNA was imprinted, with monoallelic expression from the paternal allele. In breast cancer tissues that were informative for single nucleotide polymorphism (SNP) rs8034564, there was an imbalanced expression of the two parental alleles, where the 'G' genotype was favorably imprinted over the 'A' genotype. In breast cancer patients, IRAIN was aberrantly imprinted in both tumours and peripheral blood leucocytes, exhibiting a pattern of allele-switch: the allele expressed in normal tissues was inactivated and the normally imprinted allele was expressed. Epigenetic analysis revealed that there was extensive DNA demethylation of CpG islands in the gene promoter. These data identify IRAIN lncRNA as a novel imprinted gene that is aberrantly regulated in breast cancer.

  View details for DOI 10.1016/j.ejca.2014.10.031

  View details for Web of Science ID 000346851200016

  View details for PubMedID 25465188

• An intragenic long noncoding RNA interacts epigenetically with the RUNX1 promoter and enhancer chromatin DNA in hematopoietic malignancies INTERNATIONAL JOURNAL OF CANCER Wang, H., Li, W., Guo, R., Sun, J., Cui, J., Wang, G., Hoffman, A. R., Hu, J. 2014; 135 (12): 2783-2794

  View details for DOI 10.1002/ijc.28922

  View details for Web of Science ID 000343055600005

• A novel antisense long noncoding RNA within the IGF1R gene locus is imprinted in hematopoietic malignancies. Nucleic acids research Sun, J., Li, W., Sun, Y., Yu, D., Wen, X., Wang, H., Cui, J., Wang, G., Hoffman, A. R., Hu, J. 2014; 42 (15): 9588-9601

  Abstract

  Dysregulation of the insulin-like growth factor type I receptor (IGF1R) has been implicated in the progression and therapeutic resistance of malignancies. In acute myeloid leukemia (AML) cells, IGF1R is one of the most abundantly phosphorylated receptor tyrosine kinases, promoting cell growth through the PI3K/Akt signaling pathway. However, little is known regarding the molecular mechanisms underlying IGF1R gene dysregulation in cancer. We discovered a novel intragenic long noncoding RNA (lncRNA) within the IGF1R locus, named IRAIN, which is transcribed in an antisense direction from an intronic promoter. The IRAIN lncRNA was expressed exclusively from the paternal allele, with the maternal counterpart being silenced. Using both reverse transcription-associated trap and chromatin conformation capture assays, we demonstrate that this lncRNA interacts with chromatin DNA and is involved in the formation of an intrachromosomal enhancer/promoter loop. Knockdown of IRAIN lncRNA with shRNA abolishes this intrachromosomal interaction. In addition, IRAIN was downregulated both in leukemia cell lines and in blood obtained from high-risk AML patients. These data identify IRAIN as a new imprinted lncRNA that is involved in long-range DNA interactions.

  View details for DOI 10.1093/nar/gku549

  View details for PubMedID 25092925

• Fracture risk in diabetic elderly men: the MrOS study DIABETOLOGIA Napoli, N., Strotmeyer, E. S., Ensrud, K. E., Sellmeyer, D. E., Bauer, D. C., Hoffman, A. R., Dam, T. L., Barrett-Connor, E., Palermo, L., Orwoll, E. S., Cummings, S. R., Black, D. M., Schwartz, A. V. 2014; 57 (10): 2057-2065

  Abstract

  Diabetes mellitus is associated with increased fracture risk in women but few studies are available in men. To evaluate the relationship between diabetes and prospective non-vertebral fractures in elderly men, we used data from the Osteoporotic Fractures in Men (MrOS) study.The MrOS enrolled 5,994 men (aged ≥65 years). Diabetes (ascertained by self-report, the use of medication for diabetes or an elevated fasting glucose level) was reported in 881 individuals, 80 of whom were using insulin. Hip and spine bone mineral density (BMD) was measured using dual x-ray absorptiometry (DXA). After recruitment, the men were followed for incident non-vertebral fractures using a triannual (3 yearly) questionnaire for an average of 9.1 (SD 2.7) years. The Cox proportional hazards model was used to assess the incident risk of fractures.In models adjusted for age, race, clinic site and total hip BMD, the risk of non-vertebral fracture was higher in men with diabetes compared with normoglycaemic men (HR 1.30, 95% CI 1.09, 1.54) and was elevated in men using insulin (HR 2.46, 95% CI 1.69, 3.59). Men with impaired fasting glucose did not have a higher risk of fracture compared with normoglycaemic men (HR 1.04, 95% CI 0.89, 1.21). After multivariable adjustment, the risk of non-vertebral fracture remained higher only among men with diabetes who were using insulin (HR 1.74, 95% CI 1.13, 2.69).Men with diabetes who are using insulin have an increased risk of non-vertebral fracture for a given age and BMD.

  View details for DOI 10.1007/s00125-014-3289-6

  View details for Web of Science ID 000341708900007

  View details for PubMedID 24908567

• Circulating Vitamin D, Supplement Use, and Cardiovascular Disease Risk: The MrOS Sleep Study JOURNAL OF CLINICAL ENDOCRINOLOGY & METABOLISM Bajaj, A., Stone, K. L., Peters, K., Parimi, N., Barrett-Connor, E., Bauer, D., Cawthon, P. M., Ensrud, K. E., Hoffman, A. R., Orwoll, E., Schernhammer, E. S. 2014; 99 (9): 3256-3262

  Abstract

  Evidence suggests an inverse association between circulating 25(OH) vitamin D and cardiovascular disease (CVD).To determine the association between serum 25(OH) vitamin D and risk for CVD events.From March 2000 to April 2002, participants were recruited for the Osteoporotic Fractures in Men (MrOS) study. Between December 2003 and March 2005, members of the MrOS cohort were invited to participate in the MrOS Sleep Study. Participants were recruited from 6 clinical centers across the United States and followed for a mean of 5.9 years. Three-thousand-one-hundred-thirty-five men ages 65 and older were included from the MrOS cohort, of whom 116 were excluded for missing vitamin D or CVD data. Participants were divided into two groups based on serum 25(OH) vitamin D levels, <20 ng/mL and ≥20 ng/mL. Participants were followed for CVD endpoints including coronary heart disease (CHD) and cerebrovascular events. Age- and multivariable-adjusted hazard ratios were calculated and stratified by use of vitamin D containing supplements.We observed no significant association between circulating 25(OH) vitamin D and risk of CVD event (HR, 0.91; 95% confidence interval (CI), 0.73-1.13) and CHD event (HR, 0.81; 95% CI, 0.61-1.07). For cerebrovascular events, men with vitamin D deficiency exhibited a higher risk (HR, 1.44; 95% CI, 1.00-2.08) using the minimally adjusted model and after excluding supplement users (HR, 1.70; 95% CI, 1.02-2.83).25(OH) vitamin D was not associated with risk of CVD and CHD events. However, vitamin D deficiency may be associated with an increased risk of cerebrovascular events.

  View details for DOI 10.1210/jc.2013-4178

  View details for Web of Science ID 000342341400064

  View details for PubMedID 24670083

• Long Noncoding RNA HOTAIR as an Independent Prognostic Marker in Cancer: A Meta-Analysis PLOS ONE Zhang, S., Chen, S., Yang, G., Gu, F., Li, M., Zhong, B., Hu, J., Hoffman, A., Chen, M. 2014; 9 (8)

  Abstract

  HOTAIR, a newly discovered long intergenic noncoding RNA (lincRNA), has been reported to be aberrantly expressed in many types of cancers. This meta-analysis summarizes its potential role as a biomarker in malignancy.A quantitative meta-analysis was performed through a systematic search in Pubmed, Medline and Web of Science for eligible papers on the prognostic impact of HOTAIR in cancer from inception to Feb. 28, 2014. Pooled hazard ratios (HRs) with 95% confidence interval (95% CI) were calculated to summarize the effect.Nineteen studies were included in the study, with a total of 2033 patients. A significant association was observed between high HOTAIR expression and poor overall survival (OS) in patients with cancer (pooled HR 2.22, 95% CI: 1.68-2.93). Place of residence (Asian or Western countries), type of cancer (digestive or non-digestive disease), sample size (more or less than 100), and paper quality (score more or less than 85%) did not alter the significant predictive value of HOTAIR in OS from various kinds of cancer but preoperative status did. By combining HRs from Cox multivariate analyses, we found that HOTAIR expression was an independent prognostic factor for cancer patients (pooled HR 2.26, 95% CI: 1.62-3.15). Subgroup analysis showed that HOTAIR abundance was an independent prognostic factor for cancer metastasis (HR 3.90, 95% CI: 2.25-6.74). For esophageal carcinoma, high HOTAIR expression was significantly associated with TNM stage (III/IV vs. I/II: OR 6.90, 95% CI: 2.81-16.9) without heterogeneity. In gastric cancer, HOTAIR expression was found to be significantly associated with lymph node metastases (present vs. absent: OR 4.47, 95% CI: 1.88-10.63) and vessel invasion (positive vs. negative: OR 2.88, 95% CI: 1.38-6.04) without obvious heterogeneity.HOTAIR abundance may serve as a novel predictive factor for poor prognosis in different types of cancers in both Asian and Western countries.

  View details for DOI 10.1371/journal.pone.0105538

  View details for Web of Science ID 000341303200035

  View details for PubMedID 25157956

  View details for PubMedCentralID PMC4144893

• AACE/ACE DISEASE STATE CLINICAL REVIEW: MEDICAL MANAGEMENT OF CUSHING DISEASE ENDOCRINE PRACTICE Hamrahian, A. H., Yuen, K. C., Hoffman, A. R. 2014; 20 (7): 746-757

  View details for DOI 10.4158/EP14147.RA

  View details for Web of Science ID 000350025400018

• ASSOCIATION BETWEEN THYROID FUNCTION AND OBJECTIVE AND SUBJECTIVE SLEEP QUALITY IN OLDER MEN: THE OSTEOPOROTIC FRACTURES IN MEN (MROS) STUDY ENDOCRINE PRACTICE Akatsu, H., Ewing, S. K., Stefanick, M. L., Fink, H. A., Stone, K. L., Barrett-Connor, E., Mehra, R., Ancoli-Israel, S., Redline, S., Hoffman, A. R. 2014; 20 (6): 576-586

  View details for DOI 10.4158/EP13282.OR

  View details for Web of Science ID 000338436300012

• Association Between Thyroid Function and Objective and Subjective Sleep Quality in Older Men: The Osteoporotic Fractures in Men (MrOS) Study. Endocrine practice Akatsu, H., Ewing, S. K., Stefanick, M. L., Fink, H. A., Stone, K. L., Barrett-Connor, E., Mehra, R., Ancoli-Israel, S., Redline, S., Hoffman, A. R., For The Osteoporotic Fractures In Men MrOS Research Group 2014; 20 (6): 576-586

  Abstract

  Objective: To determine the association between thyroid hormone levels and sleep quality in community-dwelling men.Methods: Among 5,994 men aged ≥65 years in the Osteoporotic Fractures in Men (MrOS) study, 682 had baseline thyroid function data, normal free thyroxine (FT4) (0.70 ≤ FT4 ≤ 1.85 ng/dL), actigraphy measurements, and were not using thyroid-related medications. Three categories of thyroid function were defined: subclinical hyperthyroid (thyroid-stimulating hormone [TSH] <0.55 mIU/L), euthyroid (TSH, 0.55 to 4.78 mIU/L), and subclinical hypothyroid (TSH >4.78 mIU/L). Objective (total hours of nighttime sleep [TST], sleep efficiency [SE], wake after sleep onset [WASO], sleep latency [SL], number of long wake episodes [LWEP]) and subjective (TST, Pittsburgh Sleep Quality Index score, Epworth Sleepiness Scale score) sleep quality parameters were measured. The association between TSH and sleep quality was examined using linear regression (continuous sleep outcomes) and log-binomial regression (categorical sleep outcomes).Results: Among the 682 men examined, 15 had subclinical hyperthyroidism and 38 had subclinical hypothyroidism. There was no difference in sleep quality between subclinical hypothyroid and euthyroid men. Compared to euthyroid men, subclinical hyperthyroid men had lower mean actigraphy TST (adjusted mean difference [95% confidence interval (CI)], -27.4 [-63.7 to 8.9] minutes), lower mean SE (-4.5% [-10.3% to 1.3%]), and higher mean WASO (13.5 [-8.0 to 35.0] minutes]), whereas 41% had increased risk of actigraphy-measured TST <6 hours (relative risk [RR], 1.41; 95% CI, 0.83 to 2.39), and 83% had increased risk of SL ≥60 minutes (RR, 1.83; 95% CI, 0.65 to 5.14) (all P>.05).Conclusion: Neither subclinical hypothyroidism nor hyperthyroidism is significantly associated with decreased sleep quality.

  View details for DOI 10.4158/EP13282.OR

  View details for PubMedID 24449663

• Epigenetic reprogramming reverses the malignant epigenotype of the MMP/TIMP axis genes in tumor cells INTERNATIONAL JOURNAL OF CANCER Zhang, S., Zhong, B., Chen, M., Yang, L., Yang, G., Li, Y., Wang, H., Wang, G., Li, W., Cui, J., Hoffman, A. R., Hu, J. 2014; 134 (7): 1583-1594

  Abstract

  Cancer progression is characterized by extensive tumor invasion into the surrounding extracellular matrix (ECM) and migration to metastatic sites. The increased proteolytic degradation of the ECM during tumor invasion is directly dependent on the activity of matrix metalloproteinases (MMPs), counter-balanced by tissue inhibitors of matrix metalloproteinases (TIMPs). In this study, we found that unbalanced expression of MMP/TIMP axis genes in tumors was correlated with aberrant epigenotypes in the various gene promoters. The malignant epigenotypes could be therapeutically corrected by a simple defined factor-mediated reprogramming approach. Correction of the abnormal epigenotypes by nuclear remodeling leads to a rebalance in the gene expression profile, an alteration in tumor cell morphology, attenuation of tumor cell migration and invasion in vitro, and reduced tumorigenicity in nude mice. We further identified the downregulation of the MKK-p38 MAPK signal pathway as an important underlying mechanism for reduced tumorigenicity in this epigenetic reprogramming model. These data demonstrate that the malignant phenotypes seen in cancer can be corrected by a nuclear remodeling mechanism, thus highlighting a novel non-chemotherapeutic, non-radiotherapeutic approach for the treatment of cancer.

  View details for DOI 10.1002/ijc.28487

  View details for Web of Science ID 000329579500007

  View details for PubMedID 24105737

• Rapid and efficient conversion of integration-free human induced pluripotent stem cells to GMP-grade culture conditions. PloS one Durruthy-Durruthy, J., Briggs, S. F., Awe, J., Ramathal, C. Y., Karumbayaram, S., Lee, P. C., Heidmann, J. D., Clark, A., Karakikes, I., Loh, K. M., Wu, J. C., Hoffman, A. R., Byrne, J., Reijo Pera, R. A., Sebastiano, V. 2014; 9 (4)

  Abstract

  Data suggest that clinical applications of human induced pluripotent stem cells (hiPSCs) will be realized. Nonetheless, clinical applications will require hiPSCs that are free of exogenous DNA and that can be manufactured through Good Manufacturing Practice (GMP). Optimally, derivation of hiPSCs should be rapid and efficient in order to minimize manipulations, reduce potential for accumulation of mutations and minimize financial costs. Previous studies reported the use of modified synthetic mRNAs to reprogram fibroblasts to a pluripotent state. Here, we provide an optimized, fully chemically defined and feeder-free protocol for the derivation of hiPSCs using synthetic mRNAs. The protocol results in derivation of fully reprogrammed hiPSC lines from adult dermal fibroblasts in less than two weeks. The hiPSC lines were successfully tested for their identity, purity, stability and safety at a GMP facility and cryopreserved. To our knowledge, as a proof of principle, these are the first integration-free iPSCs lines that were reproducibly generated through synthetic mRNA reprogramming that could be putatively used for clinical purposes.

  View details for DOI 10.1371/journal.pone.0094231

  View details for PubMedID 24718618

  View details for PubMedCentralID PMC3981795

• Rapid and Efficient Conversion of Integration-Free Human Induced Pluripotent Stem Cells to GMP-Grade Culture Conditions. PloS one Durruthy-Durruthy, J., Briggs, S. F., Awe, J., Ramathal, C. Y., Karumbayaram, S., Lee, P. C., Heidmann, J. D., Clark, A., Karakikes, I., Loh, K. M., Wu, J. C., Hoffman, A. R., Byrne, J., Reijo Pera, R. A., Sebastiano, V. 2014; 9 (4)

  View details for DOI 10.1371/journal.pone.0094231

  View details for PubMedID 24718618

• Promoter histone H3K27 methylation in the control of IGF2 imprinting in human tumor cell lines HUMAN MOLECULAR GENETICS Li, T., Chen, H., Li, W., Cui, J., Wang, G., Hu, X., Hoffman, A. R., Hu, J. 2014; 23 (1): 117-128

  Abstract

  Aberrant imprinting of the insulin-like growth factor II (IGF2) gene is a molecular hallmark of many tumors. Reactivation of the normally suppressed maternal allele leads to upregulation of the growth factor that promotes tumor growth. However, the mechanisms underlying the loss of imprinting (LOI) remain poorly defined. We examined the epigenotypes at the gene promoters that control IGF2 allelic expression. Using chromatin immunoprecipitation, we found that in cells characterized by maintenance of IGF2 imprinting, three IGF2 promoters were differentially modified, with the suppressed allele heavily methylated at histone H3K27 while the active allele was unmethylated. In the LOI tumors, however, both alleles were unmethylated, and correspondingly there was no binding of SUZ12, the docking factor of the polycomb repressive complex 2 (PRC2), and of the zinc finger-containing transcription factor (CTCF) that recruits the PRC2. Using chromatin conformation capture, we found that the CTCF-orchestrated intrachromosomal loop between the IGF2 promoters and the imprinting control region was abrogated in cells with LOI. SUZ12, which docks the PRC2 to IGF2 promoters for H3K27 methylation, was downregulated in LOI cells. These data reveal a new epigenetic control pathway related to the loss of IGF2 imprinting in tumors.

  View details for DOI 10.1093/hmg/ddt405

  View details for Web of Science ID 000328482300010

  View details for PubMedID 23962719

• Chromatin looping is needed for iPSC induction. Cell cycle Hu, J., Hoffman, A. R. 2014; 13 (1): 1-2

  View details for DOI 10.4161/cc.27017

  View details for PubMedID 24231773

• Targeted gene suppression by inducing de novo DNA methylation in the gene promoter. Epigenetics & chromatin Ma, A., Wang, H., Guo, R., Wang, Y., Li, W., Cui, J., Wang, G., Hoffman, A. R., Hu, J. 2014; 7: 20-?

  View details for DOI 10.1186/1756-8935-7-20

  View details for PubMedID 25184003

• Targeted gene suppression by inducing de novo DNA methylation in the gene promoter. Epigenetics & chromatin Ma, A., Wang, H., Guo, R., Wang, Y., Li, W., Cui, J., Wang, G., Hoffman, A. R., Hu, J. 2014; 7: 20-?

  Abstract

  Targeted gene silencing is an important approach in both drug development and basic research. However, the selection of a potent suppressor has become a significant hurdle to implementing maximal gene inhibition for this approach. We attempted to construct a 'super suppressor' by combining the activities of two suppressors that function through distinct epigenetic mechanisms.Gene targeting vectors were constructed by fusing a GAL4 DNA-binding domain with a epigenetic suppressor, including CpG DNA methylase Sss1, histone H3 lysine 27 methylase vSET domain, and Kruppel-associated suppression box (KRAB). We found that both Sss1 and KRAB suppressors significantly inhibited the expression of luciferase and copGFP reporter genes. However, the histone H3 lysine 27 methylase vSET did not show significant suppression in this system. Constructs containing both Sss1 and KRAB showed better inhibition than either one alone. In addition, we show that KRAB suppressed gene expression by altering the histone code, but not DNA methylation in the gene promoter. Sss1, on the other hand, not only induced de novo DNA methylation and recruited Heterochromatin Protein 1 (HP1a), but also increased H3K27 and H3K9 methylation in the promoter.Epigenetic studies can provide useful data for the selection of suppressors in constructing therapeutic vectors for targeted gene silencing.

  View details for DOI 10.1186/1756-8935-7-20

  View details for PubMedID 25184003

  View details for PubMedCentralID PMC4150861

• Abdominal Myosteatosis Is Independently Associated with Hyperinsulinemia and Insulin Resistance Among Older Men Without Diabetes OBESITY Miljkovic, I., Cauley, J. A., Wang, P. Y., Holton, K. F., Lee, C. G., Sheu, Y., Barrett-Connor, E., Hoffman, A. R., Lewis, C. B., Orwoll, E. S., Stefanick, M. L., Strotmeyer, E. S., Marshall, L. M. 2013; 21 (10): 2118-2125

  Abstract

  OBJECTIVE: Skeletal muscle adipose tissue (AT) infiltration (myosteatosis) increases with aging and may contribute to the development of Type 2 diabetes mellitus (T2DM). It remains unclear if myosteatosis is associated to glucose and insulin homeostasis independent of total and central adiposity. DESIGN AND METHODS: The association between intermuscular AT (IMAT) in the abdominal skeletal muscles (total, paraspinal, and psoas) and fasting serum glucose, insulin, and homeostasis model assessment of insulin resistance (HOMA-IR) in 393 nondiabetic Caucasian men aged 65+ was evaluated. Abdominal IMAT, visceral AT (VAT), and subcutaneous AT (SAT) (cm(3) ) were measured by quantitative computed tomography at the L4-L5 intervertebral space. RESULTS: In age, study site, height, and muscle volume adjusted regression analyses, total abdominal and psoas (but not paraspinal) IMAT were positively associated with glucose, insulin, and HOMA-IR (all P < 0.003). The associations between total abdominal and psoas IMAT and insulin and HOMA-IR remained significant after further adjusting for lifestyle factors, as well as duel-energy x-ray absorptiometry (DXA) measured total body fat, VAT, or SAT in separate models (all P < 0.009). CONCLUSIONS: A previously unreported, independent association between abdominal myosteatosis and hyperinsulinemia and insulin resistance among older Caucasian men was indicated. These associations may be specific for particular abdominal muscle depots, illustrating the potential importance of separately studying specific muscle groups.

  View details for DOI 10.1002/oby.20346

  View details for Web of Science ID 000325427300021

  View details for PubMedID 23408772

  View details for PubMedCentralID PMC3661705

• Cyclic Hypobaric Hypoxia Improves Markers of Glucose Metabolism in Middle-Aged Men HIGH ALTITUDE MEDICINE & BIOLOGY Marquez, J. L., Rubinstein, S., Fattor, J. A., Shah, O., Hoffman, A. R., Friedlander, A. L. 2013; 14 (3): 263-272

  Abstract

  Chronic hypoxia increases dependence on glucose in men and increases insulin sensitivity in men and women. Cyclic Variations in Altitude Conditioning (CVAC) is a novel technology that provides exposure to rapidly fluctuating cyclic hypobaric hypoxia (CHH).To test the hypothesis that markers of glucose metabolism would change with CVAC CHH, two groups of middle-aged men were exposed to 10 weeks (40 min/day, 3 day/week) of either CHH or sham (SH) sessions.CHH subjects (age: 48 ± 6, weight: 86 ± 12 kg, BMI: 27.1 ± 3, n=11) experienced cyclic pressures simulating altitudes ranging from sea level to 3048 m (week 1) and progressing to 6096 m (by week 5 through week 10). SH subjects (age: 50 ± 4, weight: 89 ± 15 kg, BMI: 27.5 ± 3, n=10) were exposed to slowly-fluctuating pressures up to 607 m (all subjects blinded to elevation). Physical function and blood markers of glucose metabolism were measured at baseline, 3, 6, and 10 weeks.Two CHH subjects were dropped from analysis for failure to progress past 3048 m (CHH: n=9). Weight and physical activity remained stable for both groups. There was a group-by-time interaction in fasting glucose (CHH: 96 ± 9 to 91 ± 7 mg/dL, SH: 94 ± 7 to 97 ± 9 mg/dL, p<0.05). Reduction in plasma glucose response to oral glucose tolerance test [area under the curve] was greater in CHH compared to SH after 10 weeks of exposure (p<0.03). Neither group experienced changes in fasting insulin, insulin response during the OGTT, or changes in a timed walk test.Ten weeks of CVAC CHH exposure improves markers of glucose metabolism in middle-aged men at risk for metabolic syndrome.

  View details for DOI 10.1089/ham.2012.1057

  View details for Web of Science ID 000324834700019

  View details for PubMedID 24028640

• Gene therapy for colorectal cancer by an oncolytic adenovirus that targets loss of the insulin-like growth factor 2 imprinting system MOLECULAR CANCER Nie, Z., Pan, Y., He, B., Gu, L., Chen, L., Li, R., Xu, Y., Gao, T., Song, G., Hoffman, A. R., Wang, S., Hu, F. 2012; 11

  Abstract

  Colorectal cancer is one of the most common malignant tumors worldwide. Loss of imprinting (LOI) of the insulin-like growth factor 2 (IGF2) gene is an epigenetic abnormality observed in human colorectal neoplasms. Our aim was to investigate the feasibility of using the IGF2 imprinting system for targeted gene therapy of colorectal cancer.We constructed a novel oncolytic adenovirus, Ad315-E1A, and a replication-deficient recombinant adenovirus, Ad315-EGFP, driven by the IGF2 imprinting system by inserting the H19 promoter, CCCTC binding factor, enhancer, human adenovirus early region 1A (E1A) and enhanced green fluorescent protein (EGFP) reporter gene into a pDC-315 shuttle plasmid. Cell lines with IGF2 LOI (HCT-8 and HT-29), which were infected with Ad315-EGFP, produced EGFP. However, no EGFP was produced in cell lines with maintenance of imprinting (HCT116 and GES-1). We found that Ad315-E1A significantly decreased cell viability and induced apoptosis only in LOI cell lines in vitro. In addition, mice bearing HCT-8-xenografted tumors, which received intratumoral administration of the oncolytic adenovirus, showed significantly reduced tumor growth and enhanced survival.Our recombinant oncolytic virus targeting the IGF2 LOI system inhibits LOI cell growth in vitro and in vivo, and provides a novel approach for targeted gene therapy.

  View details for DOI 10.1186/1476-4598-11-86

  View details for Web of Science ID 000314051700001

  View details for PubMedID 23171475

  View details for PubMedCentralID PMC3546838

• The Association of Concurrent Vitamin D and Sex Hormone Deficiency With Bone Loss and Fracture Risk in Older Men: The Osteoporotic Fractures in Men (MrOS) Study JOURNAL OF BONE AND MINERAL RESEARCH Barrett-Connor, E., Laughlin, G. A., Li, H., Nielson, C. M., Wang, P. Y., Dam, T. T., Cauley, J. A., Ensrud, K. E., Stefanick, M. L., Lau, E., Hoffman, A. R., Orwoll, E. S. 2012; 27 (11): 2306-2313

  Abstract

  Low 25-hydroxyvitamin D (VitD), low sex hormones (SH), and high sex hormone binding globulin (SHBG) levels are common in older men. We tested the hypothesis that combinations of low VitD, low SH, and high SHBG would have a synergistic effect on bone mineral density (BMD), bone loss, and fracture risk in older men. Participants were a random subsample of 1468 men (mean age 74 years) from the Osteoporotic Fractures in Men Study (MrOS) plus 278 MrOS men with incident nonspine fractures studied in a case-cohort design. "Abnormal" was defined as lowest quartile for VitD (<20 ng/mL), bioavailable testosterone (BioT, <163 ng/dL), and bioavailable estradiol (BioE, <11 pg/mL); and highest quartile for SHBG (>59 nM). Overall, 10% had isolated VitD deficiency; 40% had only low SH or high SHBG; 15% had both SH/SHBG and VitD abnormality; and 35% had no abnormality. Compared to men with all normal levels, those with both SH/SHBG and VitD abnormality tended to be older, more obese, and to report less physical activity. Isolated VitD deficiency, and low BioT with or without low VitD, was not significantly related to skeletal measures. The combination of VitD deficiency with low BioE and/or high SHBG was associated with significantly lower baseline BMD and higher annualized rates of hip bone loss than SH abnormalities alone or no abnormality. Compared to men with all normal levels, the multivariate-adjusted hazard ratio (95% confidence interval [CI]) for incident nonspine fracture during 4.6-year median follow-up was 1.2 (0.8-1.8) for low VitD alone; 1.3 (0.9-1.9) for low BioE and/or high SHBG alone; and 1.6 (1.1-2.5) for low BioE/high SHBG plus low VitD. In summary, adverse skeletal effects of low sex steroid levels were more pronounced in older men with low VitD levels. The presence of low VitD in the presence of low BioE/high SHBG may contribute substantially to poor skeletal health.

  View details for DOI 10.1002/jbmr.1697

  View details for Web of Science ID 000313729500011

  View details for PubMedID 22777902

• Successful long-term treatment of Cushing disease with mifepristone (RU486). Endocrine practice Basina, M., Liu, H., Hoffman, A. R., Feldman, D. 2012; 18 (5): e114-20

  Abstract

  We describe a girl with Cushing disease for whom surgery and radiation treatments failed and the subsequent clinical course with mifepristone therapy.We present the patient's clinical, biochemical, and imaging findings.A 16-year-old girl presented with classic Cushing disease. After transsphenoidal surgery, Cyberknife radiosurgery, ketoconazole, and metyrapone did not control her disease, and she was prescribed mifepristone, which was titrated to a maximal dosage of 1200 mg daily with subsequent symptom improvement. Mifepristone (RU486) is a high-affinity, nonselective antagonist of the glucocorticoid receptor. There is limited literature on its use as an off-label medication to treat refractory Cushing disease. Over her 8-year treatment with mifepristone, her therapy was complicated by hypertension and hypokalemia requiring spironolactone and potassium chloride. She received a 2-month drug holiday every 4 to 6 months to allow for withdrawal menstrual bleeding with medroxyprogesterone acetate. Urinary cortisol, serum cortisol, and corticotropin levels remained elevated during mifepristone drug holidays. While on mifepristone, her signs and symptoms of Cushing disease resolved. Repeated magnetic resonance imaging demonstrated stable appearance of the residual pituitary mass. Bilateral adrenalectomy was performed, and mifepristone was discontinued after 95 months of medical therapy.We describe the longest duration of mifepristone therapy thus reported for the treatment of refractory Cushing disease. Mifepristone effectively controlled all signs and symptoms of hypercortisolism. Menstruating women who take the drug on a long-term basis should receive periodic drug holidays to allow for menses. The lack of reliable serum biomarkers to monitor the success of mifepristone therapy requires careful clinical judgment and may make its use difficult in Cushing disease.

  View details for DOI 10.4158/EP11391.CR

  View details for PubMedID 22441000

• Promotion of the induction of cell pluripotency through metabolic remodeling by thyroid hormone triiodothyronine-activated PI3K/AKT signal pathway BIOMATERIALS Chen, M., Zhang, H., Wu, J., Xu, L., Xu, D., Sun, J., He, Y., Zhou, X., Wang, Z., Wu, L., Xu, S., Wang, J., Jiang, S., Zhou, X., Hoffman, A. R., Hu, X., Hu, J., Li, T. 2012; 33 (22): 5514-5523

  Abstract

  Generation of induced pluripotent stem cells (iPSCs) from somatic cells by defined factors is a mechanism-unknown, yet extremely time-consuming process. Inefficient reprogramming leads to prolonged periods of in vitro iPSC selection, resulting in subtle genetic and epigenetic abnormalities. To facilitate pluripotent reprogramming, we have identified the thyroid hormone triiodothyronine (T3) as an endogenous factor that can enhance reprogramming of human dermal fibroblasts (HDF) and umbilical cord mesenchymal stem cells (UCMSC). This potentiation of iPSC induction is associated with metabolic remodeling activity, including upregulation of key glycolytic genes, an increase in cell proliferation, and the induction of mesenchymal-epithelial transition (MET). We further identify the activation of the PI3K/AKT signal pathway by T3 as an underlying mechanism for the enhanced conversion to cell pluripotency in this model. These studies demonstrate that T3 enhances metabolic remodeling of donor cells in potentiating cell reprogramming.

  View details for DOI 10.1016/j.biomaterials.2012.04.001

  View details for Web of Science ID 000305366500003

  View details for PubMedID 22575839

  View details for PubMedCentralID PMC3358472

• Validation of FRC, a Fracture Risk Assessment Tool, in a Cohort of Older Men: The Osteoporotic Fractures in Men (MrOS) Study JOURNAL OF CLINICAL DENSITOMETRY Ettinger, B., Liu, H., Blackwell, T., Hoffman, A. R., Ensrud, K. E., Orwoll, E. S. 2012; 15 (3): 334-342

  Abstract

  We evaluated the performance of the Fracture Risk Calculator (FRC) in 5893 men who participated in the baseline visit (March 2000-April 2002) of the Osteoporotic Fractures in Men Study. FRC estimates for 10-yr hip and major osteoporotic (hip, clinical spine, forearm, and shoulder) fractures were calculated and compared with observed 10-yr fracture probabilities. Possible enhancement of the tool's performance when bone mineral density (BMD) was included was evaluated by comparing areas under receiver operating characteristic curves and by Net Reclassification Improvement (NRI). A total of 5893 men were followed-up for an average of 8.4 yr. For most quintiles of predicted fracture risk, the ratios of observed to predicted probabilities were close to unity. Area under the curves improved when BMD was included (p<0.001; 0.79 vs 0.71 for hip fracture and 0.70 vs 0.66 for major osteoporotic fracture, respectively). Using National Osteoporosis Foundation clinical treatment thresholds, BMD inclusion increased NRI significantly, 8.5% (p<0.01) for hip and 4.0% (p=0.01) for major osteoporotic fracture. We conclude that the FRC calibrates well with hip and major osteoporotic fractures observed among older men. Further, addition of BMD to the fracture risk calculation improves the tool's performance.

  View details for DOI 10.1016/j.jocd.2012.01.011

  View details for Web of Science ID 000307262000013

  View details for PubMedID 22445858

• Thyroid Function and Mortality in Older Men: A Prospective Study JOURNAL OF CLINICAL ENDOCRINOLOGY & METABOLISM Waring, A. C., Harrison, S., Samuels, M. H., Ensrud, K. E., LeBlanc, E. S., Hoffman, A. R., Orwoll, E., Fink, H. A., Barrett-Connor, E., Bauer, D. C. 2012; 97 (3): 862-870

  Abstract

  Mild abnormalities of thyroid function have been associated with both beneficial and detrimental effects on mortality.Our objective was to determine the association between continuous TSH as well as categories of thyroid function with total and cause-specific mortality in a cohort of older men.Data were analyzed from the Osteoporotic Fractures in Men (MrOS) study, a cohort of community-dwelling U.S. men aged 65 yr and older. A total of 1587 participants randomly selected for thyroid function testing were included in this analysis. TSH and free T4 were measured at baseline, and four categories of thyroid function were defined. (subclinical hyperthyroid; euthyroid; subclinical hypothyroid TSH<10 mIU/liter; and subclinical hypothyroid, TSH≥10 mIU/liter.)Total mortality, cardiovascular (CV) and cancer deaths were confirmed by review of death certificates.There were 432 deaths over a mean follow-up of 8.3 yr. In fully adjusted models, there was no association between baseline TSH and any death [relative hazard (RH)=1.01 per mIU/liter, 95% confidence interval (CI)=0.95-1.06], CV death (RH=1.05 per mIU/liter, 95% CI 0.96-1.15), or cancer death (RH=0.96 per mIU/liter, 95% CI=0.85-1.07). There was also no statistically significant association between thyroid function category and total or cause-specific mortality, but few men (n=8) had subclinical hypothyroidism with TSH levels of 10 mIU/liter or higher.A single measurement of thyroid function did not predict total or cause-specific mortality in this cohort. These data support neither a beneficial nor a detrimental effect of subclinical thyroid dysfunction in older men.Subclinical thyroid dysfunction is not associated with an increased risk of all-cause or CV mortality in older men.

  View details for DOI 10.1210/jc.2011-2684

  View details for Web of Science ID 000301229600051

  View details for PubMedID 22238396

• Long-Term Surveillance of Growth Hormone Therapy JOURNAL OF CLINICAL ENDOCRINOLOGY & METABOLISM Rosenfeld, R. G., Cohen, P., Robison, L. L., Bercu, B. B., Clayton, P., Hoffman, A. R., Radovick, S., Saenger, P., Savage, M. O., Wit, J. M. 2012; 97 (1): 68-72

  View details for DOI 10.1210/jc.2011-2294

  View details for Web of Science ID 000300393800035

  View details for PubMedID 22174422

• Higher Testosterone Levels Are Associated with Less Loss of Lean Body Mass in Older Men JOURNAL OF CLINICAL ENDOCRINOLOGY & METABOLISM LeBlanc, E. S., Wang, P. Y., Lee, C. G., Barrett-Connor, E., Cauley, J. A., Hoffman, A. R., Laughlin, G. A., Marshall, L. M., Orwoll, E. S. 2011; 96 (12): 3855-3863

  Abstract

  Little information exists about longitudinal changes in body composition and physical function in relation to sex hormone levels in older men.The aim of the study was to determine associations of testosterone, estradiol, and SHBG with changes in body composition and physical function.We conducted a prospective cohort study within the Osteoporotic Fractures in Men (MrOS) study at six U.S. clinical centers.A total of 5994 ambulatory men aged 65 yr or older enrolled in the MrOS. We examined 1183 men with complete measures of sex steroid hormones, body composition, and some measure of physical function. Intervention: There were no interventions.Sex steroids were measured by mass spectrometry in serum collected at baseline. Measurements of body composition using dual-energy x-ray absorptiometry and physical performance (grip strength, leg power, timed chair stands, narrow walk, and 6-m walk) were performed at baseline and repeated 4.5 yr later.Overall, men lost 1.3 kg (±4.4 sd) weight between study visits. Lean mass, especially appendicular, declined less at higher baseline testosterone levels (P < 0.05). These associations were most evident in the 40% of men who lost more than 2.0 kg during follow-up. In weight losers, higher testosterone was associated with less decline in timed chair stands. Estradiol was not related to body composition or physical function changes. Higher SHBG was associated with less loss of appendicular lean mass and grip strength.Higher endogenous testosterone is associated with reduced loss of lean mass and lower extremity function in older men losing weight. Endogenous testosterone may contribute to healthy aging.

  View details for DOI 10.1210/jc.2011-0312

  View details for Web of Science ID 000298295200061

  View details for PubMedID 21976718

  View details for PubMedCentralID PMC3232620

• COMBINED CHANGES IN MUSCLE AND FAT ASSOCIATED WITH LOSS IN POWER Lee, C. G., Marshall, L. M., LeBlanc, E. S., Hoffman, A. R., Cauley, J. A., Strotmeyer, E. S., Cawthon, P. M., Orwoll, E. OXFORD UNIV PRESS INC. 2011: 112–112

  View details for Web of Science ID 000303602000505

• Insulin Sensitizers May Attenuate Lean Mass Loss in Older Men With Diabetes DIABETES CARE Lee, C. G., Boyko, E. J., Barrett-Connor, E., Miljkovic, I., Hoffman, A. R., Everson-Rose, S. A., Lewis, C. E., Cawthon, P. M., Strotmeyer, E. S., Orwoll, E. S. 2011; 34 (11): 2381-2386

  Abstract

  To examine longitudinal changes in total and appendicular lean body mass in older men with impaired fasting glucose (IFG) or diabetes and to determine whether these changes differ by diabetes treatment.A total of 3,752 ambulatory men aged ≥ 65 years at baseline participated in a multicenter longitudinal cohort study. Baseline glycemic status was categorized as normoglycemia, IFG, undiagnosed/untreated diabetes, or treated diabetes. Insulin sensitizer medication use (metformin and/or thiazolidinediones) was assessed by prescription medication inventory. The change in total lean and appendicular lean mass was derived from dual X-ray absorptiometry scans taken at baseline and 3.5 ± 0.7 years later.This male cohort included 1,853 individuals with normoglycemia, 1,403 with IFG, 234 with untreated diabetes, 151 with diabetes treated with insulin sensitizers, and 111 with diabetes treated without insulin sensitizers. Men with untreated diabetes, diabetes treated without insulin sensitizers, or IFG had greater percentage loss in total or appendicular lean mass (P ≤ 0.05 in comparison to normoglycemic men). There remained a significantly greater percentage loss in appendicular lean mass for these groups even after adjustment for medical comorbidities or lifestyle factors. In contrast, the percentage loss in total or appendicular lean mass in men with diabetes treated with insulin sensitizers was significantly less than that in normoglycemic men in minimally and fully adjusted models.Skeletal muscle loss was accelerated in men with IFG and diabetes, except when the latter was treated with insulin sensitizers. These findings suggest that insulin sensitizers may attenuate muscle loss.

  View details for DOI 10.2337/dc11-1032

  View details for Web of Science ID 000296955100010

  View details for PubMedID 21926282

  View details for PubMedCentralID PMC3198278

• IGFBP-2 Enhances VEGF Gene Promoter Activity and Consequent Promotion of Angiogenesis by Neuroblastoma Cells ENDOCRINOLOGY Azar, W. J., Azar, S. H., Higgins, S., Hu, J., Hoffman, A. R., Newgreen, D. F., Werther, G. A., Russo, V. C. 2011; 152 (9): 3332-3342

  Abstract

  IGF binding protein (IGFBP)-2 is one of the most significant genes in the signature of major aggressive cancers. Previously, we have shown that IGFBP-2 enhances proliferation and invasion of neuroblastoma cells, suggesting that IGFBP-2 activates a protumorigenic gene expression program in these cells. Gene expression profiling in human neuroblastoma SK-N-SHEP (SHEP)-BP-2 cells indicated that IGFBP-2 overexpression activated a gene expression program consistent with enhancement of tumorigenesis. Regulation was significant for genes involved in proliferation/survival, migration/adhesion, and angiogenesis, including the up-regulation of vascular endothelial growth factor (VEGF) mRNA (>2-fold). Specific transcriptional activation of the VEGF gene by IGFBP-2 overexpression was demonstrated via cotransfection of a VEGF promoter Luciferase construct in SHEP-BP-2. Cotransfection of VEGF promoter Luciferase construct with IGFBP-2 protein in wild-type SHEP cells indicated that transactivation of VEGF promoter only occurs in the presence of intracellular IGFBP-2. Cell fractionation and immunofluorescence in SHEP-BP-2 cells demonstrated nuclear localization of IGFBP-2. These findings suggest that transcriptional activation of VEGF promoter is likely to be mediated by nuclear IGFBP-2. The levels of secreted VEGF (up to 400 pg/10(6) cells) suggested that VEGF might elicit angiogenic activity. Hence, SHEP-BP-2 cells and control clones cultured in collagen sponge were xenografted onto chick embryo chorioallantoic membrane. Neomicrovascularization was observed by 72 h, solely in the SHEP-BP-2 cell xenografts. In conclusion, our data indicate that IGFBP-2 is an activator of aggressive behavior in cancer cells, involving nuclear entry and activation of a protumorigenic gene expression program, including transcriptional regulation of the VEGF gene and consequent proangiogenic activity of NB cell xenografts in vivo.

  View details for DOI 10.1210/en.2011-1121

  View details for Web of Science ID 000294161000006

  View details for PubMedID 21750048

• Optimized clinical performance of growth hormone with an expanded genetic code PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Cho, H., Daniel, T., Buechler, Y. J., Litzinger, D. C., Maio, Z., Putnam, A. H., Kraynov, V. S., Sim, B., Bussell, S., Javahishvili, T., Kaphle, S., Viramontes, G., Ong, M., Chu, S., Becky, G. C., Lieu, R., Knudsen, N., Castiglioni, P., Norman, T. C., Axelrod, D. W., Hoffman, A. R., Schultz, P. G., DiMarchi, R. D., Kimmel, B. E. 2011; 108 (22): 9060-9065

  Abstract

  The ribosomal incorporation of nonnative amino acids into polypeptides in living cells provides the opportunity to endow therapeutic proteins with unique pharmacological properties. We report here the first clinical study of a biosynthetic protein produced using an expanded genetic code. Incorporation of p-acetylphenylalanine (pAcF) at distinct locations in human growth hormone (hGH) allowed site-specific conjugation with polyethylene glycol (PEG) to produce homogeneous hGH variants. A mono-PEGylated mutant hGH modified at residue 35 demonstrated favorable pharmacodynamic properties in GH-deficient rats. Clinical studies in GH-deficient adults demonstrated efficacy and safety comparable to native human growth hormone therapy but with increased potency and reduced injection frequency. This example illustrates the utility of nonnative amino acids to optimize protein therapeutics in an analogous fashion to the use of medicinal chemistry to optimize conventional natural products, low molecular weight drugs, and peptides.

  View details for DOI 10.1073/pnas.1100387108

  View details for Web of Science ID 000291106200035

  View details for PubMedID 21576502

  View details for PubMedCentralID PMC3107295

• Genetic analysis of vertebral trabecular bone density and cross-sectional area in older men OSTEOPOROSIS INTERNATIONAL Zmuda, J. M., Yerges-Armstrong, L. M., Moffett, S. P., Klei, L., Kammerer, C. M., Roeder, K., Cauley, J. A., Kuipers, A., Ensrud, K. E., Nestlerode, C. S., Hoffman, A. R., Lewis, C. E., Lang, T. F., Barrett-Connor, E., Ferrell, R. E., Orwoll, E. S. 2011; 22 (4): 1079-1090

  Abstract

  We investigated 383 bone candidate genes for associations between single nucleotide polymorphisms and vertebral trabecular volumetric bone mineral density (vBMD) and cross-sectional area (CSA) in 2,018 Caucasian men aged ≥ 65 years. SNPs in TGFBR3, SOST, KL, CALCR, LEP, CSF1R, PTN, GNRH2, FGFR2, and MEPE were associated with vBMD and SNPs in CYP11B1, DVL2, DLX5, WNT4, and PAX7 were associated with CSA in independent study samples (p < 0.005).Vertebral bone mineral density and cross-sectional area are important determinants of vertebral bone strength. Little is known about the specific genetic variants that influence these phenotypes in humans.We investigated the potential genetic variants associated with vertebral trabecular volumetric BMD and CSA measured by quantitative computed tomography. We initially tested for association between these phenotypes and 4608 tagging and potentially functional single nucleotide polymorphisms (SNPs) in 383 candidate genes in 862 community-dwelling Caucasian men aged ≥ 65 years in the Osteoporotic Fractures in Men Study.SNP associations were then validated by genotyping an additional 1,156 randomly sampled men from the same cohort. We identified 11 SNPs in 10 genes (TGFBR3, SOST, KL, CALCR, LEP, CSF1R, PTN, GNRH2, FGFR2, and MEPE) that were consistently associated with trabecular vBMD and five SNPs in five genes (CYP11B1, DVL2, DLX5, WNT4, and PAX7) that were consistently associated with CSA in both samples (p < 0.005).None of the SNPs associated with trabecular vBMD were associated with CSA. Our findings raise the possibility that at least some of the loci for vertebral trabecular BMD and bone size may be distinct.

  View details for DOI 10.1007/s00198-010-1296-0

  View details for Web of Science ID 000287854500008

  View details for PubMedID 21153022

• Associated Chromosome Trap for Identifying Long-range DNA Interactions JOVE-JOURNAL OF VISUALIZED EXPERIMENTS Ling, J., Hoffman, A. R. 2011

  View details for DOI 10.3791/2621

  View details for Web of Science ID 000209214700023

• Mortality Risk in Older Men Associated with Changes in Weight, Lean Mass, and Fat Mass JOURNAL OF THE AMERICAN GERIATRICS SOCIETY Lee, C. G., Boyko, E. J., Nielson, C. M., Stefanick, M. L., Bauer, D. C., Hoffman, A., Dam, T. L., Lapidus, J. A., Cawthon, P. M., Ensrud, K. E., Orwoll, E. S. 2011; 59 (2): 233-240

  Abstract

  To evaluate risk of all-cause mortality associated with changes in body weight, total lean mass, and total fat mass in older men.Longitudinal cohort study.Six U.S. clinical centers.Four thousand three hundred thirty-one ambulatory men aged 65 to 93 at baseline.Repeated measurements of body weight and total lean and fat mass were taken using dual-energy X-ray absorptiometry 4.6 ± 0.4 years apart. Percentage changes in these measures were categorized as gain (+5%), loss (-5%), or stable (-5% to +5%). Deaths were verified centrally according to death certificate reviews, and proportional hazard models were used to estimate the risk of mortality.After accounting for baseline lifestyle factors and medical conditions, a higher risk of mortality was found for men with weight loss (hazard rat (HR)=1.84, 95% confidence interval (CI)=1.50-2.26), total lean mass loss (HR=1.78, 95% CI=1.45-2.19), and total fat mass loss (HR=1.72, 95% CI=1.34-2.20) than for men who were stable for each body composition measure. Men with total fat mass gain had a slightly greater mortality risk (HR=1.29, 95% CI=0.99-1.67) than those who remained stable. These associations did not differ according to baseline age, obesity, or self-reported health status (P for interactions >.10), although self-reported weight loss intent altered mortality risks with total fat mass (P for interaction=.04) and total lean mass (P for interaction=.09) change.Older men who lost weight, total lean mass, or total fat mass had a higher risk of mortality than men who remained stable.

  View details for DOI 10.1111/j.1532-5415.2010.03245.x

  View details for Web of Science ID 000287240700006

  View details for PubMedID 21288234

  View details for PubMedCentralID PMC3403719

• Diagnosis and Treatment of Hyperprolactinemia: An Endocrine Society Clinical Practice Guideline JOURNAL OF CLINICAL ENDOCRINOLOGY & METABOLISM Melmed, S., Casanueva, F. F., Hoffman, A. R., Kleinberg, D. L., Montori, V. M., Schlechte, J. A., Wass, J. A. 2011; 96 (2): 273-288

  Abstract

  The aim was to formulate practice guidelines for the diagnosis and treatment of hyperprolactinemia.The Task Force consisted of Endocrine Society-appointed experts, a methodologist, and a medical writer.This evidence-based guideline was developed using the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) system to describe both the strength of recommendations and the quality of evidence.One group meeting, several conference calls, and e-mail communications enabled consensus. Committees and members of The Endocrine Society, The European Society of Endocrinology, and The Pituitary Society reviewed and commented on preliminary drafts of these guidelines.Practice guidelines are presented for diagnosis and treatment of patients with elevated prolactin levels. These include evidence-based approaches to assessing the cause of hyperprolactinemia, treating drug-induced hyperprolactinemia, and managing prolactinomas in nonpregnant and pregnant subjects. Indications and side effects of therapeutic agents for treating prolactinomas are also presented.

  View details for DOI 10.1210/jc.2010-1692

  View details for Web of Science ID 000286972500029

  View details for PubMedID 21296991

• Putative Tumor Suppressor miR-145 Inhibits Colon Cancer Cell Growth by Targeting Oncogene Friend Leukemia Virus Integration 1 Gene CANCER Zhang, J., Guo, H., Zhang, H., Wang, H., Qian, G., Fan, X., Hoffman, A. R., Hu, J., Ge, S. 2011; 117 (1): 86-95

  Abstract

  Tumor suppressor microRNA miR-145 is commonly down-regulated in colon carcinoma tissues, but its specific role in tumors remains unknown.In this study, the authors identified the Friend leukemia virus integration 1 gene (FLI1) as a novel target of miR-145. FLI1 is involved in t(11;22)(q24:q12) reciprocal chromosomal translocation in Ewing sarcoma, and its expression appears to be associated with biologically more aggressive tumors.The authors demonstrated that miR-145 targets a putative microRNA regulatory element in the 3'-untranslated region (UTR) of FLI1, and its abundance is reversely associated with FLI1 expression in colon cancer tissues and cell lines. By using a luciferase/FLI1 3'-UTR reporter system, they found that miR-145 down-regulated the reporter activity, and this down-regulation was reversed by anti-miR-145. Mutation of the miR-145 microRNA regulatory element sequence in the FLI1 3'-UTR abolished the activity of miR-145. miR-145 decreased FLI1 protein but not FLI1 mRNA, suggesting a mechanism of translational regulation. Furthermore, the authors demonstrated that miR-145 inhibited cell proliferation and sensitized LS174T cells to 5-fluorouracil-induced apoptosis.Taken together, these results suggest that miR-145 functions as a tumor suppressor by down-regulating oncogenic FLI1 in colon cancer.

  View details for DOI 10.1002/cncr.25522

  View details for Web of Science ID 000285368300013

  View details for PubMedID 20737575

• INCREASED RISK OF LEAN MASS LOSS ASSOCIATED WITH INSULIN RESISTANCE IN OLDER MEN Lee, C. G., Boyko, E. J., Strotmeyer, E. S., Cawthon, P. M., Hoffman, A. R., Everson-Rose, S., Barrett-Connor, E., Orwoll, E. OXFORD UNIV PRESS INC. 2010: 41–41

  View details for Web of Science ID 000286006701195

• Serum 25-OH vitamin D levels and risk of developing prostate cancer in older men CANCER CAUSES & CONTROL Barnett, C. M., Nielson, C. M., Shannon, J., Chan, J. M., Shikany, J. M., Bauer, D. C., Hoffman, A. R., Barrett-Connor, E., Orwoll, E., Beer, T. M. 2010; 21 (8): 1297-1303

  Abstract

  Multiple studies have shown clear evidence of vitamin D's anti-tumor effects on prostate cancer cells in laboratory experiments, but the evidence has not been consistent in humans. We sought to examine the association between vitamin D and prostate cancer risk in a cohort of older men.We conducted a prospective case-cohort study nested within the multicenter Osteoporotic Fractures in Men (MrOS) study. Baseline serum 25-OH vitamin D was measured in a randomly selected sub-cohort of 1,433 men > or = 65 years old without a history of prostate cancer and from all participants with an incident diagnosis of prostate cancer (n = 297). Cox proportional hazards models were used to evaluate the associations between quartiles of total 25-OH vitamin D and incident prostate cancer, as well as Gleason score.In comparison with the lowest quartile of 25-OH vitamin D, the hazard ratio for the highest quartile of 25-OH vitamin D was 1.22 (CI 0.50-1.72, p = 0.25), no trend across quartiles (p = 0.94) or association with Gleason score was observed. Adjustment for covariates did not alter the results.In this prospective cohort of older men, we found no association between serum 25-OH vitamin D levels and subsequent risk of prostate cancer.

  View details for DOI 10.1007/s10552-010-9557-y

  View details for Web of Science ID 000280065400015

  View details for PubMedID 20383574

• Targeted tumor gene therapy based on loss of IGF2 imprinting CANCER BIOLOGY & THERAPY Pan, Y., He, B., Li, T., Zhu, C., Zhang, L., Wang, B., Xu, Y., Qu, L., Hoffman, A. R., Wang, S., Hu, J. 2010; 10 (3)

  Abstract

  Loss of imprinting (LOI) of the insulin-like growth factor 2 gene (IGF2) is one of the most common epigenetic abnormalities seen in human neoplasms. LOI may be associated with the lack of Zinc-finger DNA binding protein CTCF-mediated enhancer insulation, presumably due to the gain of methylation on the maternal allele of the differentially methylated domain (DMD) of the imprinting control region. This results in an interaction between the IGF2 promoters and enhancers; and IGF2 is produced from both alleles. In this study we investigated the feasibility of a novel anti-cancer adenovirus (AdDC312-DT-A) driven by H19 enhancer DMD-H19 promoter complex. Cell lines with IGF2 LOI (HCT-8, HT-29 and H-522) that were infected with AdDC312-EGFP produced the EGFP protein. However, in cells in which imprinting was maintained (MOI) (MCF-7 and GES-1), no EGFP protein was produced. The AdDC312-DT-A significantly decreased cell viability and induced apoptosis only in LOI cells in vitro, and suppressed tumour development in HCT-8 xenografts in nude mice. In conclusion, the toxin gene therapy proves effective in inhibiting LOI cell growth in vitro and in vivo and provides a novel option for targeted gene therapy based on loss of IGF2 imprinting.

  View details for Web of Science ID 000281005600012

  View details for PubMedID 20592487

  View details for PubMedCentralID PMC3040838

• Targeted knockdown of Bcl2 in tumor cells using a synthetic TRAIL 3 '-UTR microRNA INTERNATIONAL JOURNAL OF CANCER Zhang, J., Huang, S., Zhang, H., Wang, H., Guo, H., Qian, G., Fan, X., Lu, J., Hoffman, A. R., Hu, J., Ge, S. 2010; 126 (9): 2229-2239

  Abstract

  Targeting tumor-related overexpression of anti-apoptotic Bcl2 protein by RNAi has been suggested as a potential treatment for cancer. However, the stability of RNAi and its delivery are still major obstacles to the clinical testing of Bcl2 RNAi. Here, we explore a novel strategy of expressing a synthetic Bcl2 microRNA (smRNA) in the 3' untranslated region (UTR) of the tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), an apoptosis-inducing protein without apparent toxic effects in normal cells. TRAIL was specifically expressed from the human telomerase reverse transcriptase promoter (pTRT) that is active in many human tumors. Using this approach, we demonstrated that pTRT drove the tumor-specific expression of Bcl2 smRNA, which was processed by the host RNAi machinery and silenced endogenous Bcl2 expression in tumor cells. Bcl2 smRNA induced tumor cell apoptosis by activating caspase-3 and led to significant sensitization of tumor cells to TRAIL-induced apoptosis, while normal cells were spared. We also showed that the combined therapy of TRAIL-induced apoptosis and Bcl2 downregulation was superior to the mono-therapy of TRAIL or Bcl2 smRNA alone. This study proves a general paradigm for cancer therapy by using 3' UTR microRNA technology.

  View details for DOI 10.1002/ijc.24821

  View details for Web of Science ID 000276173700022

  View details for PubMedID 19676053

  View details for PubMedCentralID PMC2924819

• Mortality Risks with Body Composition Change in Older Men. Annual Meeting of the American-Geriatrics-Society Lee, C. G., Boyko, E. J., Nielson, C. M., Bauer, D. C., Hoffman, A. R., Cawthon, P. M., Ensrud, K. E., Lapidus, J. A., Orwoll, E. S. WILEY-BLACKWELL. 2010: 76–76

  View details for Web of Science ID 000276247100219

• Transient in vitro epigenetic reprogramming of skin fibroblasts into multipotent cells BIOMATERIALS Zhu, X., Pan, X., Wang, W., Chen, Q., Pang, R., Cai, X., Hoffman, A. R., Hu, J. 2010; 31 (10): 2779-2787

  Abstract

  Multipotent stem cells have the potential to establish a new field of promising regenerative medicine to treat tissue damage, genetic disorders, and degenerative diseases. However, limited resource of stem cells has turned to be an evitable obstacle in clinical applications. We utilized a simple in vitro epigenetic reprogramming approach to convert skin fibroblasts into multipotent cells. After transient reprogramming, stem cell markers, including Oct4 and Nanog, became activated in the treated cells. The reprogrammed cells were multipotent as demonstrated by their ability to differentiate into a variety of cells and to form teratomas. Genomic imprinting of insulin-like growth factor II (Igf2) and H19 was not affected by this short period of cell reprogramming. This study may provide an alternative strategy to efficiently generate patient-specific stem cells for basic and clinical research, solving major hurdles of virally-induced pluripotent stem (iPS) cells that entail the potential risks of mutation, gene instability, and malignancy.

  View details for DOI 10.1016/j.biomaterials.2009.12.027

  View details for Web of Science ID 000275777800009

  View details for PubMedID 20044135

  View details for PubMedCentralID PMC2909839

• Loss of IGF2 imprinting is associated with abrogation of long-range intrachromosomal interactions in human cancer cells HUMAN MOLECULAR GENETICS Vu, T. H., Nguyen, A. H., Hoffman, A. R. 2010; 19 (5): 901-919

  Abstract

  Nuclear architecture and chromatin geography are important factors in the regulation of gene expression, as these components may play a vital epigenetic role both in normal physiology as well as in the initiation and progression of malignancies. Using a modification of the chromosome conformation capture (3C) technique, we examined long-range chromatin interactions of the imprinted human IGF2 gene. We demonstrate that numerous intrachromosomal interactions occur along both parental alleles in normal tissues, where the IGF2 is paternally expressed, as well as in normal liver where gene expression is biallelic. Long-range and allele-specific interactions occur between the IGF2/H19 imprinting control region-1 (ICR1) and ICR2, a region which regulates an imprinted gene cluster nearly a megabase distant from IGF2. Loss of genomic imprinting is a common epigenetic event in cancer, and long-range interactions have not been examined in malignant cells. In cancer cell lines in which IGF2 imprinting is maintained (MOI), essentially all of the 3C interactions seen in normal cells were preserved. However, in cells in which IGF2 imprinting was lost (LOI), nearly all of the long-range chromatin interactions involving IGF2 were abrogated. A three-dimensional computer model depicts the physical interactions between the IGF2 promoter and ICR1 in MOI cells, while the model of LOI lung cancer cells is flattened with few long-range interactions. This dramatic change in the three-dimension configuration of the chromatin at the IGF2 locus in LOI cancer cells suggests that the loss of imprinting may lead to a variety of changes in gene expression in addition to changes in IGF2 transcription.

  View details for DOI 10.1093/hmg/ddp558

  View details for Web of Science ID 000274341400014

  View details for PubMedID 20015958

• Serum 25-Hydroxyvitamin D and the Risk of Hip and Nonspine Fractures in Older Men JOURNAL OF BONE AND MINERAL RESEARCH Cauley, J. A., Parimi, N., Ensrud, K. E., Bauer, D. C., Cawthon, P. M., Cummings, S. R., Hoffman, A. R., Shikany, J. M., Barrett-Connor, E., Orwoll, E. 2010; 25 (3): 545-553

  Abstract

  The association between vitamin D levels and incident fractures in older men is uncertain. To test the hypothesis that low serum 25-hydroxyvitamin D [(25(OH)D] levels are associated with an increased risk of fracture, we performed a case-cohort study of 436 men with incident nonspine fractures, including 81 hip fractures, and a random subcohort of 1608 men; average follow-up time 5.3 years. Serum vitamin D(2) and vitamin D(3) were measured on baseline sera using mass spectrometry and summed for total vitamin D. Modified Cox proportional hazards models were used to estimate the hazard ratio (HR) of fracture with 95% confidence intervals (CIs). Multivariable models included age, clinic, season, race, height, weight, and physical activity. The mean (SD) total 25(OH)D was 24.6 (7.8) ng/mL in nonspine fracture subjects, 21.5 (7.9) ng/mL in hip fracture subjects, and 25.2 (7.8) ng/mL in controls (nonspine fracture subjects versus nonpatients, p = .14; hip fracture subjects versus controls, p < .0001). 25(OH)D levels were unrelated to nonspine fractures. One SD decrease in total 25(OH)D was associated with an increased risk of hip fracture (multivariate HR = 1.60; 95% CI 1.18-2.17). Compared with men in the top quartile of total 25(OH)D (> or =28), the HR of hip fracture was 2.36 (95% CI 1.08-5.15) for men in the lowest quartile (<20) (p = .009 for trend). Adjusting for hip bone mineral density attenuated the association by more than 50% (p = .065 for trend). Low serum 25(OH)D concentrations are associated with a higher risk of hip fracture in older men. Measurement of 25(OH)D may be useful in identifying men at high risk of hip fracture.

  View details for DOI 10.1359/jbmr.090826

  View details for Web of Science ID 000276767700016

  View details for PubMedID 19775201

• Bone Mass and Strength in Older Men With Type 2 Diabetes: The Osteoporotic Fractures in Men Study JOURNAL OF BONE AND MINERAL RESEARCH Petit, M. A., Paudel, M. L., Taylor, B. C., Hughes, J. M., Strotmeyer, E. S., Schwartz, A. V., Cauley, J. A., Zmuda, J. M., Hoffman, A. R., Ensrud, K. E. 2010; 25 (2): 285-291

  Abstract

  The effects of type 2 diabetes mellitus (T2DM) on bone volumetric density, bone geometry, and estimates of bone strength are not well established. We used peripheral quantitative computed tomography (pQCT) to compare tibial and radial bone volumetric density (vBMD, mg/cm(3)), total (ToA, mm(2)) and cortical (CoA, mm(2)) bone area and estimates of bone compressive and bending strength in a subset (n = 1171) of men (> or =65 years of age) who participated in the multisite Osteoporotic Fractures in Men (MrOS) study. Analysis of covariance-adjusted bone data for clinic site, age, and limb length (model 1) and further adjusted for body weight (model 2) were used to compare data between participants with (n = 190) and without (n = 981) T2DM. At both the distal tibia and radius, patients with T2DM had greater bone vBMD (+2% to +4%, model 1, p < .05) and a smaller bone area (ToA -1% to -4%, model 2, p < .05). The higher vBMD compensated for lower bone area, resulting in no differences in estimated compressive bone strength at the distal trabecular bone regions. At the mostly cortical bone midshaft sites of the radius and tibia, men with T2DM had lower ToA (-1% to -3%, p < .05), resulting in lower bone bending strength at both sites after adjusting for body weight (-2% to -5%, p < .05) despite the lack of difference in cortical vBMD at these sites. These data demonstrate that older men with T2DM have bone strength that is low relative to body weight at the cortical-rich midshaft of the radius despite no difference in cortical vBMD.

  View details for DOI 10.1359/jbmr.090725

  View details for Web of Science ID 000275215500011

  View details for PubMedID 19594301

• Candidate Gene Analysis of Femoral Neck Trabecular and Cortical Volumetric Bone Mineral Density in Older Men JOURNAL OF BONE AND MINERAL RESEARCH Yerges, L. M., Klei, L., Cauley, J. A., Roeder, K., Kammerer, C. M., Ensrud, K. E., Nestlerode, C. S., Lewis, C., Lang, T. F., Barrett-Connor, E., Moffett, S. P., Hoffman, A. R., Ferrell, R. E., Orwoll, E. S., Zmuda, J. M. 2010; 25 (2): 330-338

  Abstract

  In contrast to conventional dual-energy X-ray absorptiometry, quantitative computed tomography separately measures trabecular and cortical volumetric bone mineral density (vBMD). Little is known about the genetic variants associated with trabecular and cortical vBMD in humans, although both may be important for determining bone strength and osteoporotic risk. In the current analysis, we tested the hypothesis that there are genetic variants associated with trabecular and cortical vBMD at the femoral neck by genotyping 4608 tagging and potentially functional single-nucleotide polymorphisms (SNPs) in 383 bone metabolism candidate genes in 822 Caucasian men aged 65 years or older from the Osteoporotic Fractures in Men Study (MrOS). Promising SNP associations then were tested for replication in an additional 1155 men from the same study. We identified SNPs in five genes (IFNAR2, NFATC1, SMAD1, HOXA, and KLF10) that were robustly associated with cortical vBMD and SNPs in nine genes (APC, ATF2, BMP3, BMP7, FGF18, FLT1, TGFB3, THRB, and RUNX1) that were robustly associated with trabecular vBMD. There was no overlap between genes associated with cortical vBMD and trabecular vBMD. These findings identify novel genetic variants for cortical and trabecular vBMD and raise the possibility that some genetic loci may be unique for each bone compartment.

  View details for DOI 10.1359/jbmr.090729

  View details for Web of Science ID 000275215500017

  View details for PubMedID 19619005

• High-Density Association Study of 383 Candidate Genes for Volumetric BMD at the Femoral Neck and Lumbar Spine Among Older Men JOURNAL OF BONE AND MINERAL RESEARCH Yerges, L. M., Klei, L., Cauley, J. A., Roeder, K., Kammerer, C. M., Moffett, S. P., Ensrud, K. E., Nestlerode, C. S., Marshall, L. M., Hoffman, A. R., Lewis, C., Lang, T. F., Barrett-Connor, E., Ferrell, R. E., Orwoll, E. S., Zmuda, J. M. 2009; 24 (12): 2039-2049

  Abstract

  Genetics is a well-established but poorly understood determinant of BMD. Whereas some genetic variants may influence BMD throughout the body, others may be skeletal site specific. We initially screened for associations between 4608 tagging and potentially functional single nucleotide polymorphisms (SNPs) in 383 candidate genes and femoral neck and lumbar spine volumetric BMD (vBMD) measured from QCT scans among 862 community-dwelling white men >or=65 yr of age in the Osteoporotic Fractures in Men Study (MrOS). The most promising SNP associations (p < 0.01) were validated by genotyping an additional 1156 white men from MrOS. This analysis identified 8 SNPs in 6 genes (APC, DMP1, FGFR2, FLT1, HOXA, and PTN) that were associated with femoral neck vBMD and 13 SNPs in 7 genes (APC, BMPR1B, FOXC2, HOXA, IGFBP2, NFATC1, and SOST) that were associated with lumbar spine vBMD in both genotyping samples (p < 0.05). Although most associations were specific to one skeletal site, SNPs in the APC and HOXA gene regions were associated with both femoral neck and lumbar spine BMD. This analysis identifies several novel and robust genetic associations for volumetric BMD, and these findings in combination with other data suggest the presence of genetic loci for volumetric BMD that are at least to some extent skeletal-site specific.

  View details for DOI 10.1359/JBMR.090524

  View details for Web of Science ID 000273216600014

  View details for PubMedID 19453261

• Association of a high mobility group gene (HMGA2) variant with bone mineral density BONE Kuipers, A., Zhang, Y., Cauley, J. A., Nestlerode, C. S., Chu, Y., Bunker, C. H., Patrick, A. L., Wheeler, V. W., Hoffman, A. R., Orwoll, E. S., Zmuda, J. M. 2009; 45 (2): 295-300

  Abstract

  High mobility group (HMG) proteins regulate chromatin architecture and gene expression. Constitutional rearrangement of an HMG family member, HMGA2, in an 8-year old boy resulted in extreme overgrowth and advanced bone development. Moreover, a recent genome-wide association study documented an association between a variant in the 3' untranslated region of HMGA2 (rs1042725) and height in otherwise healthy individuals. We attempted to extend these findings by testing if this HMGA2 polymorphism is associated with other skeletal measures in two large population cohorts of diverse race/ethnicity. Genotyping was completed in 1680 Afro-Caribbean men aged > or = 40 years and 1548 Caucasian American men aged > or = 69 years. Bone mineral density (BMD) was assessed with peripheral quantitative computed tomography. The minor allele frequency of rs1042725 was 32% among Afro-Caribbeans and 48% among Caucasians (p<0.0001). No association was observed with height in either study cohort. However, presence of the minor allele of this SNP was associated with decreased tibia trabecular volumetric BMD in both populations (p=0.007 Afro-Caribbean; p=0.0007 Caucasian). Real-time quantitative RT-PCR and Western blot analysis demonstrated HMGA2 mRNA and protein expression in the human fetal osteoblast cell line, hFOB. Our analyses suggest a novel association between a common genetic variant in HMGA2 and trabecular BMD in ethnically diverse older men. Additional research is needed to better understand the role of HMGA2 in the regulation of bone metabolism.

  View details for DOI 10.1016/j.bone.2009.04.197

  View details for Web of Science ID 000268206300021

  View details for PubMedID 19376282

• Nocturnal Arrhythmias Across a Spectrum of Obstructive and Central Sleep-Disordered Breathing in Older Men Outcomes of Sleep Disorders in Older Men (MrOS Sleep) Study ARCHIVES OF INTERNAL MEDICINE Mehra, R., Stone, K. L., Varosy, P. D., Hoffman, A. R., Marcus, G. M., Blackwell, T., Ibrahim, O. A., Salem, R., Redline, S. 2009; 169 (12): 1147-1155

  Abstract

  Rates of cardiac arrhythmias increase with age and may be associated with clinically significant morbidity. We studied the association between sleep-disordered breathing (SDB) with nocturnal atrial fibrillation or flutter (AF) and complex ventricular ectopy (CVE) in older men.A total of 2911 participants in the Outcomes of Sleep Disorders in Older Men Study underwent unattended polysomnography. Nocturnal AF and CVE were ascertained by electrocardiogram-specific analysis of the polysomnographic data. Exposures were (1) SDB defined by respiratory disturbance index (RDI) quartile (a major index including all apneas and hypopneas), and ancillary definitions incorporating (2) obstructive events, obstructive sleep apnea (OSA; Obstructive Apnea Hypopnea Index quartile), or (3) central events, central sleep apnea (CSA; Central Apnea Index category), and (4) hypoxia (percentage of sleep time with <90% arterial oxygen percent saturation). Multivariable logistic regression analyses were performed.An increasing RDI quartile was associated with increased odds of AF and CVE (P values for trend, .01 and <.001, respectively). The highest RDI quartile was associated with increased odds of AF (odds ratio [OR], 2.15; 95% confidence interval [CI], 1.19-3.89) and CVE (OR, 1.43; 95% CI, 1.12-1.82) compared with the lowest quartile. An increasing OSA quartile was significantly associated with increasing CVE (P value for trend, .01) but not AF. Central sleep apnea was more strongly associated with AF (OR, 2.69; 95% CI, 1.61-4.47) than CVE (OR, 1.27; 95% CI, 0.97-1.66). Hypoxia level was associated with CVE (P value for trend, <.001); those in the highest hypoxia category had an increased odds of CVE (OR, 1.62; 95% CI, 1.23-2.14) compared with the lowest quartile.In this large cohort of older men, increasing severity of SDB was associated with a progressive increase in odds of AF and CVE. When SDB was characterized according to central or obstructive subtypes, CVE was associated most strongly with OSA and hypoxia, whereas AF was most strongly associated with CSA, suggesting that different sleep-related stresses may contribute to atrial and ventricular arrhythmogenesis in older men.

  View details for Web of Science ID 000267239300010

  View details for PubMedID 19546416

  View details for PubMedCentralID PMC2802061

• Vitamin D Deficiency in Older Men JOURNAL OF CLINICAL ENDOCRINOLOGY & METABOLISM Orwoll, E., Nielson, C. M., Marshall, L. M., Lambert, L., Holton, K. F., Hoffman, A. R., Barrett-Connor, E., Shikany, J. M., Dam, T., Cauley, J. A. 2009; 94 (4): 1214-1222

  Abstract

  Vitamin D deficiency is not adequately evaluated in older men.The aim of the study was to determine the prevalence of vitamin D deficiency and identify risk factors for its occurrence.We conducted a cross-sectional evaluation of 1606 older men in the general community who were enrolled in the Osteoporotic Fractures in Men Study.A randomly selected subcohort of a large population of men from six U.S. communities participated in the study.Serum concentrations of 25-hydroxyvitamin D(2) [25(OH)D(2)] and 25(OH)D(3) were measured using mass spectrometry.Deficiency [25(OH)D <20 ng/ml] was present in 26%, and insufficiency (<30 ng/ml) was present in 72%. Deficiency was particularly common among men during the winter and spring (especially in the northern communities) and in the oldest and more obese men. For instance, in Caucasian men in winter or spring who were >80 yr old, did not engage in lawn/garden work, and had a body mass index greater than 25 kg/m(2) and vitamin D intake below 400 IU/d, the prevalence of vitamin D deficiency was 86%. 25(OH)D(2) levels were present in a small fraction of men and accounted for a low proportion of total 25(OH)D levels. The use of vitamin D supplements was reported by 58% of men, but supplement use had a small effect on total 25(OH)D levels and, despite supplement use, low levels remained frequent.Vitamin D deficiency is common in older men and is especially prevalent in obese, sedentary men living at higher latitudes. Use of vitamin D supplements at levels reported here did not result in adequate vitamin D nutrition.

  View details for DOI 10.1210/jc.2008-1784

  View details for Web of Science ID 000265145100027

  View details for PubMedID 19174492

• The impact of hypopituitarism on function and performance in subjects with recent history of traumatic brain injury and aneurysmal subarachnoid haemorrhage BRAIN INJURY Srinivasan, L., Roberts, B., Bushnik, T., Englander, J., Spain, D. A., Steinberg, G. K., Ren, L., Sandel, M. E., Al-Lawati, Z., Teraoka, J., Hoffman, A. R., Katznelson, L. 2009; 23 (7-8): 639-648

  Abstract

  To correlate deficient pituitary function with life satisfaction and functional performance in subjects with a recent history of traumatic brain injury (TBI) and subarachnoid haemorrhage (SAH).Cross-sectional study.Eighteen subjects with TBI and 16 subjects with SAH underwent pituitary hormonal and functional assessments 5-12 months following the event. Adrenal reserve was assessed with a 1 mcg cosyntropin stimulation test and growth hormone deficiency (GHD) was diagnosed by insufficient GH response to GHRH-Arginine stimulation. Assessments of life satisfaction and performance-function included the Satisfaction with Life Scale (SWLS), Craig Handicap Assessment and Reporting Technique (CHART) and the Mayo Portland Adaptability Inventory-4 (MPAI-4).Hypopituitarism was present in 20 (58.8%) subjects, including 50% with adrenal insufficiency. Hypothyroidism correlated with worse performance on SWLS and CHART measures. GHD was associated with poorer performance on CHART and MPAI-4 scale.In this series of subjects with history of TBI and SAH, hypothyroidism and GHD were associated with diminished life satisfaction and performance-function on multiple assessments. Further studies are necessary to determine the appropriate testing of adrenal reserve in this population and to determine the benefit of pituitary hormone replacement therapy on function following brain injury.

  View details for DOI 10.1080/02699050902970778

  View details for Web of Science ID 000267370600008

• The Association of Bone Mineral Density with Prostate Cancer Risk in the Osteoporotic Fractures in Men (MrOS) Study CANCER EPIDEMIOLOGY BIOMARKERS & PREVENTION Farhat, G. N., Taioli, E., Cauley, J. A., Zmuda, J. M., Orwoll, E., Bauer, D. C., Wilt, T. J., Hoffman, A. R., Beer, T. M., Shikany, J. M., Daniels, N., Chan, J., Fink, H. A., Barrett-Connor, E., Parsons, J. K., Bunker, C. H. 2009; 18 (1): 148-154

  Abstract

  We investigated the association of bone mineral density (BMD) measures with prostate cancer (PCa) risk in older men enrolled in the Osteoporotic Fractures in Men Study. We hypothesized that men with higher BMD, a marker of exposure to endogenous sex hormones, would have an increased incidence of PCa. The cohort included 4,597 men (89% White, 65 years or older) with no prior history of PCa. Baseline total body, total hip, and spine BMD were assessed using dual energy X-ray absorptiometry. Prostate cancer was confirmed by review of medical records. Cox regression was used to assess the association of BMD quartiles with incident PCa, adjusting for age, body mass index, and other covariates. During an average follow-up of 5.2 years, 5.6% (n = 255) of men developed PCa. Total body BMD was inversely associated with incident PCa, with a significant trend for decreasing PCa risk with increasing BMD quartiles (P(trend) = 0.007). Men in the highest total body BMD quartile had a 41% reduced risk for PCa (hazard ratio, 0.59; 95% confidence interval, 0.40-0.86), compared with men in the lowest quartile. Total hip and spine BMD did not exhibit significant relationships with PCa. Associations of BMD measures differed for low-grade (Gleason sum, 2-6) versus high-grade tumors (Gleason sum, >or=7). Significant inverse relationships with high-grade disease were noted at the total body and total hip sites. However, no associations were observed with low-grade disease. Our results provide support for an inverse association between BMD and PCa risk. Possible pathophyisological mechanisms linking BMD and PCa should be elucidated.

  View details for DOI 10.1158/1055-9965.EPI-08-0415

  View details for Web of Science ID 000262424200019

  View details for PubMedID 19124492

• CTCF regulates allelic expression of Igf2 by orchestrating a promoter-polycomb repressive complex 2 intrachromosomal loop MOLECULAR AND CELLULAR BIOLOGY Li, T., Hu, J., Qiu, X., Ling, J., Chen, H., Wang, S., Hou, A., Vu, T. H., Hoffman, A. R. 2008; 28 (20): 6473-6482

  Abstract

  CTCF is a zinc finger DNA-binding protein that regulates the epigenetic states of numerous target genes. Using allelic regulation of mouse insulin-like growth factor II (Igf2) as a model, we demonstrate that CTCF binds to the unmethylated maternal allele of the imprinting control region (ICR) in the Igf2/H19 imprinting domain and forms a long-range intrachromosomal loop to interact with the three clustered Igf2 promoters. Polycomb repressive complex 2 is recruited through the interaction of CTCF with Suz12, leading to allele-specific methylation at lysine 27 of histone H3 (H3-K27) and to suppression of the maternal Igf2 promoters. Targeted mutation or deletion of the maternal ICR abolishes this chromatin loop, decreases allelic H3-K27 methylation, and causes loss of Igf2 imprinting. RNA interference knockdown of Suz12 also leads to reactivation of the maternal Igf2 allele and biallelic Igf2 expression. CTCF and Suz12 are coprecipitated from nuclear extracts with antibodies specific for either protein, and they interact with each other in a two-hybrid system. These findings offer insight into general epigenetic mechanisms by which CTCF governs gene expression by orchestrating chromatin loop structures and by serving as a DNA-binding protein scaffold to recruit and bind polycomb repressive complexes.

  View details for DOI 10.1128/MCB.00204-08

  View details for Web of Science ID 000259634800026

  View details for PubMedID 18662993

• Guidelines for the treatment of growth hormone excess and growth hormone deficiency in adults JOURNAL OF ENDOCRINOLOGICAL INVESTIGATION Giustina, A., Barkan, A., Chanson, P., Grossman, A., Hoffman, A., Ghigo, E., Casanueva, F., Colao, A., Lamberts, S., Sheppard, M., Melmed, S. 2008; 31 (9): 820-838

  Abstract

  The V Consensus Group Meeting on 'Guidelines for Treatment of GH Excess and GH Deficiency in the Adult' was an international workshop held on February 20-22, 2006 in Santa Monica, California, USA. The principal aim of this meeting was to provide guidelines for the evaluation and treatment of adults with either form of abnormal GH secretion: GH excess or GH deficiency. The workshop included debates as to the choice of primary treatment, discussions of the targets for adequate treatment, and concluded with presentations on open issues germane to adult GH treatment including the role of GH in malignancies, the impact of longterm treatment on bone, and a cost-benefit analysis. The meeting was comprised of 66 delegates representing 13 different countries.

  View details for Web of Science ID 000261148400013

  View details for PubMedID 18997495

• A complex deoxyribonucleic acid looping configuration associated with the silencing of the maternal Igf2 allele MOLECULAR ENDOCRINOLOGY Qiu, X., Vu, T. H., Lu, Q., Ling, J. Q., Li, T., Hou, A., Wang, S. K., Chen, H. L., Hu, J. F., Hoffman, A. R. 2008; 22 (6): 1476-1488

  Abstract

  Alternate interactions between the H19 imprinting control region (ICR) and one of the two Igf2 differentially methylated regions has been proposed as a model regulating the reciprocal imprinting of Igf2 and H19. To study the conformation of this imprint switch, we performed a systematic structural analysis across the 140 kb of the mouse Igf2-H19 region, which includes enhancers located both between the two genes as well as downstream of H19, by using a scanning chromosome conformation capture (3C) technique. Our results suggest that on the active paternal Igf2 allele, the various enhancers have direct access to the Igf2 promoters, whereas the imprinted silent maternal Igf2 allele assumes a complex three-dimensional knotted loop that keeps the enhancers away from the Igf2 promoters and allows them to interact with the H19 promoter. This complex DNA looping of the maternal allele is formed by interactions involving differentially methylated region 1, the ICR, and enhancers. Binding of CTC-binding factor to the maternal, unmethylated ICR in conjunction with the presence of multicomplex components including interchromosomal interactions, create a barrier blocking the access of all enhancers to Igf2, thereby silencing the maternal Igf2. This silencing configuration exists in newborn liver, mouse embryonic fibroblast, and embryonic stem cells and persists during mitosis, conferring a mechanism for epigenetic memory.

  View details for DOI 10.1210/me.2007-0474

  View details for Web of Science ID 000256307800017

  View details for PubMedID 18356289

• Systematic review: The effects of growth hormone on athletic performance ANNALS OF INTERNAL MEDICINE Liu, H., Bravata, D. M., Olkin, I., Friedlander, A., Liu, V., Roberts, B., Bendavid, E., Saynina, O., Salpeter, S. R., Garber, A. M., Hoffman, A. R. 2008; 148 (10): 747-U59

  Abstract

  Human growth hormone is reportedly used to enhance athletic performance, although its safety and efficacy for this purpose are poorly understood.To evaluate evidence about the effects of growth hormone on athletic performance in physically fit, young individuals.MEDLINE, EMBASE, SPORTDiscus, and Cochrane Collaboration databases were searched for English-language studies published between January 1966 and October 2007.Randomized, controlled trials that compared growth hormone treatment with no growth hormone treatment in community-dwelling healthy participants between 13 and 45 years of age.2 authors independently reviewed articles and abstracted data.44 articles describing 27 study samples met inclusion criteria; 303 participants received growth hormone, representing 13.3 person-years of treatment. Participants were young (mean age, 27 years [SD, 3]), lean (mean body mass index, 24 kg/m2 [SD, 2]), and physically fit (mean maximum oxygen uptake, 51 mL/kg of body weight per minute [SD, 8]). Growth hormone dosage (mean, 36 microg/kg per day [SD, 21]) and treatment duration (mean, 20 days [SD, 18] for studies giving growth hormone for >1 day) varied. Lean body mass increased in growth hormone recipients compared with participants who did not receive growth hormone (increase, 2.1 kg [95% CI, 1.3 to 2.9 kg]), but strength and exercise capacity did not seem to improve. Lactate levels during exercise were statistically significantly higher in 2 of 3 studies that evaluated this outcome. Growth hormone-treated participants more frequently experienced soft tissue edema and fatigue than did those not treated with growth hormone.Few studies evaluated athletic performance. Growth hormone protocols in the studies may not reflect real-world doses and regimens.Claims that growth hormone enhances physical performance are not supported by the scientific literature. Although the limited available evidence suggests that growth hormone increases lean body mass, it may not improve strength; in addition, it may worsen exercise capacity and increase adverse events. More research is needed to conclusively determine the effects of growth hormone on athletic performance.

  View details for Web of Science ID 000256372200004

  View details for PubMedID 18347346

• Generation of novel adipocyte monolayer cultures from embryonic stem cells 44th Annual Meeting of the American-Society-for-Cell-Biology Chen, T. L., Shen, W., Qiu, X., Li, T., Hoffman, A. R., Kraemer, F. B. MARY ANN LIEBERT INC. 2007: 371–80

  Abstract

  Here we show a simplified and improved method to produce large quantities of evenly distributed monolayer cultures that display major characteristics of adipocytes. These cultures are applicable for quantitative analysis for biochemical and molecular events in adipogenesis during development and may provide a useful system for high-throughput drug screening assays of antiobesity drugs. In our method, we treated embryoid bodies (EBs) with all-trans retinoic acid (ATRA) for 3 days, 1 day after they attached to the gelatin-coated culture plates without further transfer. The cells were maintained in insulin and trioiodothyronine (T(3))-containing medium until day 12, when they were dispersed by enzymatic digestion and replated onto multiple culture plates. Two days later, adipocyte induction factors were added for 6 days and examined 6 days later. The amount of lipid droplet-laden adipocytes in the culture reached approximately 80%, with a nearly five-fold increase in GPDH activity. The cells expressed high levels of adipose-specific proteins (adipocyte markers), including PPARgamma2, ALBP, LPL, HSL, perilipin, and DGAT1. The adipocytes are functionally active, as evidenced by their response to lipolytic agents, such as forskolin, Bt2-cAMP, and isoproterenol, with more than 20-fold increases in glycerol release.

  View details for DOI 10.1089/scd.2006.0037

  View details for Web of Science ID 000247721800005

  View details for PubMedID 17610367

• Effects of growth hormone and pioglitazone in viscerally obese adults with impaired glucose tolerance: A factorial clinical trial PLOS CLINICAL TRIALS Attallah, H., Friedlander, A. L., Nino-Murcia, M., Hoffman, A. R. 2007; 2 (5)

  Abstract

  Recombinant human growth hormone (GH) and pioglitazone (PIO) in abdominally obese adults with impaired glucose tolerance were evaluated under the hypothesis that the combination attenuates GH-induced increases in glucose concentrations, reduces visceral adipose tissue (VAT), and improves insulin sensitivity over time.Randomized, double-blind, placebo-controlled, 2 x 2 factorial design.Veterans Affairs Palo Alto Health Care System, Palo Alto, California, United States.62 abdominally obese adults aged 40-75 with impaired glucose tolerance.GH (8 microg/kg/d, or placebo) and pioglitazone (30 mg/d, or placebo) for 40 wk.Baseline and after 40 wk of treatment, VAT content was quantified by CT scan, glucose tolerance was assessed using a 75-g oral glucose tolerance test, and insulin sensitivity was measured using steady-state plasma glucose levels obtained during insulin suppression test.BASELINE: body mass index (BMI), plasma glucose, and visceral fat content were similar. 40 wk: visceral fat area declined 23.9 +/- 7.4 cm(2) in GH group, mean difference from placebo: -28.1 cm(2) (95% CI -49.9 to -6.3 cm(2); p = 0.02). Insulin resistance declined 52 +/- 11.8 mg/dl with PIO, mean difference from placebo of -58.8 mg/dl (95% CI -99.7 to -18.0 mg/dl; p = 0.01). VAT and SSPG declined with GH and PIO combined, mean differences from placebo of -31.4 cm(2) (95% CI -56.5 cm(2) to -6.3 cm(2); p = 0.02) and -55.3 mg/dl (95% CI -103.9 to -6.7 mg/dl; p = 0.02), respectively. Fasting plasma glucose increased transiently in GH group. No significant changes in BMI were observed.Addition of PIO to GH attenuated the short-term diabetogenic effect of GH; the drug combination reduced VAT and insulin resistance over time. GH plus PIO may have added benefit on body composition and insulin sensitivity in the metabolic syndrome.

  View details for DOI 10.1371/journal.pctr.0020021

  View details for Web of Science ID 000246737100002

  View details for PubMedID 17479164

• Correction of aberrant imprinting of IGF2 in human tumors by nuclear transfer-induced epigenetic reprogramming EMBO JOURNAL Chen, H. L., Li, T., Qiu, X. W., Wu, J., Ling, J. Q., Sun, Z. H., Wang, W., Chen, W., Hou, A., Vu, T. H., Hoffman, A. R., Hu, J. 2006; 25 (22): 5329-5338

  Abstract

  Loss of genomic imprinting of insulin-like growth factor II (IGF2) is a hallmark of many human neoplasms. We attempted to correct this aberrant epigenotype by transferring nuclei from human tumor cells that showed loss of IGF2 imprinting into enucleated mouse and human fibroblasts that had maintained normal IGF2 imprinting. After nuclear transfer, the abnormal biallelic expression of IGF2 in tumor nuclei transiently converted to normal monoallelic imprinted expression in the reconstructed diploid cells. In tetraploid hybrid cells, however, normal IGF2 imprinting was permanently restored in the tumor genome. Inhibition of the synthesis of putative trans imprinting factors with cycloheximide led to loss of IGF2 imprinting in normal cultured fibroblasts, suggesting that normal cells produce proteins that act in trans to induce or maintain genomic imprinting. These data demonstrate that an abnormal tumor epigenotype can be corrected by in vitro reprogramming, and suggest that loss of imprinting is associated with the loss of activity of non-CTCF trans imprinting factor(s) that are either inactivated or mutated in tumors.

  View details for DOI 10.1038/sj.emboj.7601399

  View details for Web of Science ID 000242215000009

  View details for PubMedID 17082775

  View details for PubMedCentralID PMC1636609

• Prevalence, severity, and health correlates of lower urinary tract symptoms among older men: The MrOS study UROLOGY Taylor, B. C., Wilt, T. J., Fink, H. A., Lambert, L. C., Marshall, L. M., Hoffman, A. R., Beer, T. M., Bauer, D. C., Zmuda, J. M., Orwoll, E. S. 2006; 68 (4): 804-809

  Abstract

  To describe the prevalence, severity, and health correlates of lower urinary tract symptoms (LUTS) in older community-dwelling U.S. men.We performed a cross-sectional analysis from a cohort study recruited from six U.S. clinical centers. This analysis included 5284 men without a history of prostate cancer who were at least 65 years of age. Participants completed questionnaires regarding the presence and severity of LUTS, including the American Urological Association Symptom and Bother indexes. Health status measures included the Medical Outcomes Survey SF-12 and self-rated health and instrumental activities of daily living.LUTS were absent in 2.3%, mild in 51.6%, moderate in 39.6%, and severe in 6.6%. Dissatisfaction with the urinary symptoms increased with LUTS severity (P <0.001); 19.8% of moderate and 58.1% of men with severe LUTS reported feeling mostly unsatisfied to terrible with their present urinary symptoms. The prevalence, severity, and dissatisfaction with LUTS increased with age. Men reporting moderate or severe LUTS were 1.41-fold (95% confidence interval 1.23 to 1.61) and 1.51-fold (95% confidence interval 1.23 to 1.85) more likely to rate their overall health quality as fair to very poor for their age instead of good to excellent, even after controlling for age and comorbid conditions. Increased LUTS also was independently associated with increased impairment in instrumental activities of daily living and poorer SF-12 scores.Moderate-to-severe LUTS is common in community-dwelling elderly U.S. men. In this study, LUTS severity was associated with poorer health quality and a greater prevalence of an inability to perform activities of daily living. The association of LUTS severity with poor health warrants increased clinical attention.

  View details for DOI 10.1016/j.urology.2006.04.019

  View details for Web of Science ID 000241719700025

  View details for PubMedID 17070357

• Visceral obesity, impaired glucose tolerance, metabolic syndrome, and growth hormone therapy 19th Annual National Cooperative Growth Study/1st Annual National Cooperative Metabolic Study Investigator Meeting Attallah, H., Friedlander, A. L., Hoffman, A. R. CHURCHILL LIVINGSTONE. 2006: S62–S67

  Abstract

  Overweight adults with impaired glucose tolerance have a 5-10% risk of developing diabetes per year, and insulin resistance is an important cause of progression to diabetes in these individuals. Weight loss has been shown to improve insulin sensitivity and prevent or delay progression to diabetes. According to recent studies, the improvement in insulin sensitivity that occurs with weight loss is closely linked to the reduction of visceral adipose tissue (VAT), the collection of intra-abdominal adipose depots that includes omental and intrahepatic fat. After controlling for BMI, whole body fat, and subcutaneous fat, only VAT is an independent predictor of endogenous insulin sensitivity and glucose tolerance before or after weight loss. This, in turn, suggests that reducing VAT is crucial to improving insulin sensitivity and preventing diabetes in high-risk individuals. Recombinant human growth hormone (GH) is a lipolytic drug that reduces total body, abdominal, and visceral fat in growth hormone-deficient (GHD) adults. Several studies have reported substantial reductions in VAT following GH treatment in this population. Like GHD adults, abdominally obese individuals have increased VAT, insulin resistance, and growth hormone levels that are below normal during continuous 24-h monitoring. These similarities have prompted a number of recent investigations in abdominally obese adults that reported significant reductions in truncal and visceral fat and an improvement in insulin sensitivity following prolonged GH administration. However, other studies have shown that insulin resistance and glucose concentrations transiently worsen during the first few weeks of GH treatment and that these deleterious effects can persist even after VAT reduction has occurred. Prior studies involving GH treatment were generally limited to adults who were normoglycemic at baseline. Less is known about the effects of GH in adults with impaired glucose tolerance or diabetes. The effects of GH used in conjunction with insulin sensitizers on glycemic control and VAT in patients with impaired glucose tolerance will be reviewed.

  View details for DOI 10.1016/j.ghir.2006.03.004

  View details for Web of Science ID 000239821100011

  View details for PubMedID 16624603

• Epigenetics and long-range interactions. 37th Annual Meeting of the Environmental-Mutagen-Society Hoffman, A. R., Ling, J. Q. WILEY-LISS. 2006: 405–

  View details for Web of Science ID 000239647900024

• Endocrine responses to acute and chronic high-altitude exposure (4,300 meters): modulating effects of caloric restriction AMERICAN JOURNAL OF PHYSIOLOGY-ENDOCRINOLOGY AND METABOLISM Barnholt, K. E., Hoffman, A. R., Rock, P. B., Muza, S. R., Fulco, C. S., Braun, B., Holloway, L., Mazzeo, R. S., Cymerman, A., Friedlander, A. L. 2006; 290 (6): E1078-E1088

  Abstract

  High-altitude anorexia leads to a hormonal response pattern modulated by both hypoxia and caloric restriction (CR). The purpose of this study was to compare altitude-induced neuroendocrine changes with or without energy imbalance and to explore how energy sufficiency alters the endocrine acclimatization process. Twenty-six normal-weight, young men were studied for 3 wk. One group [hypocaloric group (HYPO), n = 9] stayed at sea level and consumed 40% fewer calories than required to maintain body weight. Two other groups were deployed to 4,300 meters (Pikes Peak, CO), where one group (ADQ, n = 7) was adequately fed to maintain body weight and the other [deficient group (DEF), n = 10] had calories restricted as above. HYPO experienced a typical CR-induced reduction in many hormones such as insulin, testosterone, and leptin. At altitude, fasting glucose, insulin, and epinephrine exhibited a muted rise in DEF compared with ADQ. Free thyroxine, thyroid-stimulating hormone, and norepinephrine showed similar patterns between the two altitude groups. Morning cortisol initially rose higher in DEF than ADQ at 4,300 meters, but the difference disappeared by day 5. Testosterone increased in both altitude groups acutely but declined over time in DEF only. Adiponectin and leptin did not change significantly from sea level baseline values in either altitude group regardless of energy intake. These data suggest that hypoxia tends to increase blood hormone concentrations, but anorexia suppresses elements of the endocrine response. Such suppression results in the preservation of energy stores but may sacrifice the facilitation of oxygen delivery and the use of oxygen-efficient fuels.

  View details for DOI 10.1152/ajpendo.00449.2005

  View details for Web of Science ID 000237803300003

  View details for PubMedID 16380390

• Efficacy of a long-acting growth hormone (GH) preparation in patients with adult GH deficiency JOURNAL OF CLINICAL ENDOCRINOLOGY & METABOLISM Hoffman, A. R., Biller, B. M., Cook, D., Baptista, J., Silverman, B. L., Dao, L., Attie, K. M., Fielder, P., Maneatis, T., Lippe, B. 2005; 90 (12): 6431-6440

  Abstract

  Treatment of adult GH deficiency (AGHD) with daily injections of GH results in decreased adipose mass, increased lean body mass (LBM), increased bone mineral density, and improved quality of life.This study seeks to determine whether a depot preparation of GH given every 14 d would lead to comparable decreases in trunk adipose tissue as daily GH.This open-label, randomized study compares subjects receiving depot GH, daily GH, or no therapy.The study was performed at 23 university or local referral endocrine centers.One hundred thirty-five adults with AGHD syndrome participated in the study.Subjects were randomized to receive depot GH (n = 51), daily GH (n = 53), or no treatment (n = 31) for 32 wk. The dose of GH was titrated so that IGF-I was less than or equal to +2 SD of the age-adjusted normal range.Trunk adipose tissue was the main outcome measure as measured by dual energy x-ray absorptiometry.The percentage of the trunk region that is fat increased by 0.4 in the no treatment group, but decreased by 3.2 (P = 0.001 vs. untreated) in the GH depot group and by 2.5 (P < 0.004 vs. untreated) in the daily GH group. Visceral adipose tissue area decreased by 9.1% in the GH depot group and by 6.8% in the daily GH group. LBM and high-density lipoprotein increased in both treatment groups. Side effect profiles were similar. Three subjects receiving GH experienced serious episodes of adrenal insufficiency.GH diminishes trunk and visceral adipose tissue and increases LBM in AGHD. A depot form of GH that is administered every 14 d is as safe and effective as daily GH injections.

  View details for DOI 10.1210/jc.2005-0928

  View details for Web of Science ID 000233754000015

  View details for PubMedID 16159930

• IVF results in de novo DNA methylation and histone methylation at an Igf2-H19 imprinting epigenetic switch MOLECULAR HUMAN REPRODUCTION Li, T., Vu, T. H., Ulaner, G. A., Littman, E., Ling, J. Q., Chen, H. L., Hu, J. F., Behr, B., Giudice, L., Hoffman, A. R. 2005; 11 (9): 631-640

  Abstract

  Recent studies suggest that IVF and assisted reproduction technologies (ART) may result in abnormal genomic imprinting, leading to an increased frequency of Angelman syndrome (AS) and Beckwith-Weidemann syndrome (BWS) in IVF children. To learn how ART might alter the epigenome, we examined morulas and blastocysts derived from C57BL/6J X M. spretus F1 mice conceived in vivo and in vitro and determined the allelic expression of four imprinted genes: Igf2, H19, Cdkn1c and Slc221L. IVF-derived mouse embryos that were cultured in human tubal fluid (HTF) (Quinn's advantage) media displayed a high frequency of aberrant H19 imprinting, whereas in vivo and IVF embryos showed normal maternal expression of Cdkn1c and normal biallelic expression of Igf2 and Slc221L. Embryonic stem (ES) cells derived from IVF blastocysts also showed abnormal Igf2/H19 imprinting. Allele-specific bisulphite PCR reveals abnormal DNA methylation at a CCCTC-binding factor (CTCF) site in the imprinting control region (ICR), as the normally unmethylated maternal allele acquired a paternal methylation pattern. Chromatin immunoprecipitation (ChIP) assays indicate an increase of lysine 4 methylation (dimethyl Lys4-H3) on the paternal chromatin and a gain in lysine 9 methylation (trimethyl Lys9-H3) on the maternal chromatin at the same CTCF-binding site. Our results indicate that de novo DNA methylation on the maternal allele and allele-specific acquisition of histone methylation lead to aberrant Igf2/H19 imprinting in IVF-derived ES cells. We suggest that ART, which includes IVF and various culture media, might cause imprinting errors that involve both aberrant DNA methylation and histone methylation at an epigenetic switch of the Igf2-H19 gene region.

  View details for DOI 10.1093/molehr/gah230

  View details for Web of Science ID 000233361600003

  View details for PubMedID 16219628

• Treatment of the adult growth hormone deficiency syndrome: Directions for future research 18th Annual National Cooperative Growth Study/5th Annual National Cooperative Somatropin Surveillance Investigator Meeting Hoffman, A. R. CHURCHILL LIVINGSTONE. 2005: S48–S52

  View details for DOI 10.1016/j.ghir.2005.06.010

  View details for Web of Science ID 000231443900011

• Effect of GMCSF on development and gene imprinting in preimplantation mouse embryos. 53rd Annual Meeting of the Pacific-Coast-Reproductive-Society Littman, E. D., Ling, J. Q., Ulaner, G. A., Vu, T. H., Dasig, D., Lyon, J., Giudic, L. C., Hoffman, A. R., Behr, B. ELSEVIER SCIENCE INC. 2005: S8–S8

  View details for Web of Science ID 000229048000005

• Promoter-restricted histone code, not the differentially methylated DNA regions or antisense transcripts, marks the imprinting status of IGF2R in human and mouse HUMAN MOLECULAR GENETICS Vu, T. H., Li, T., Hoffman, A. R. 2004; 13 (19): 2233-2245

  Abstract

  Imprinting of the mouse Igf2r depends upon an intronic differentially methylated DNA region (DMR) and the presence of the Air antisense transcript. However, biallelic expression of mouse Igf2r in brain occurs despite the presence of Air, and biallelic expression of human IGF2R in peripheral tissues occurs despite the presence of an intronic DMR. We examined histone modifications throughout the mouse and human Igf2r/IGF2R using chromatin immuno-precipitation (ChIP) assays in combination with quantitative real time PCR. Methylation of Lys4 and Lys9 of histone H3 in the promoter regions marks the active and silenced alleles, respectively. We measured di- and tri-methyl Lys4 and Lys9 across the Igf2r and Air promoters. While both di- and tri-methyl Lys4 marked the active Igf2r and the active Air allele, tri-methyl Lys9, but not di-methyl Lys9, marked the suppressed Air allele. We show here that enrichment of parental allele-specific histone modifications in the promoter region, rather than the presence of DNA methylation or antisense transcription, correctly identifies the tissue- and species- specific imprinting status of Igf2r/IGF2R. We discuss these findings in light of recent progress in identifying specific components of the epigenetic marks in imprinted genes.

  View details for DOI 10.1093/hmg/ddh244

  View details for Web of Science ID 000223941500007

  View details for PubMedID 15294879

• Insulin-like growth factor 1 as a predictor of ischemic stroke outcome in the elderly AMERICAN JOURNAL OF MEDICINE Denti, L., Annoni, V., Cattadori, E., Salvagnini, M. A., Visioli, S., Merli, M. F., Corradi, F., Ceresini, G., Valenti, G., Hoffman, A. R., Ceda, G. P. 2004; 117 (5): 312-317

  Abstract

  To examine whether serum insulin-like growth factor 1 (IGF-1) and IGF binding protein 3 (IGFBP-3) concentrations, determined early after the onset of stroke, are predictive of clinical outcome in elderly patients.The sample comprised 85 patients (mean [+/- SD] age, 83 +/- 7.4 years; range, 67 to 99 years; 34% male) who were admitted with acute stroke to a geriatric ward between January 1998 and June 2000, and 88 control patients who were similar in age and sex. Clinical and laboratory assessments, computed tomographic scan of the head, carotid ultrasonography, and electrocardiography were employed to define the clinical and etiologic stroke subtype. Fasting blood samples were collected within 24 hours of admission for IGF-I and IGFBP-3 measurement. Univariate and multiple logistic regression analyses, with adjustment for other related clinical covariates, were used to assess the relation of IGF-I and IGFBP-3 to poor outcome, defined as severe disability (Barthel index <60/100) or death, at 1 month (or at discharge), 3 months, and 6 months.Mean (+/- SD) IGF-1 levels were lower in patients with stroke than in controls (69 +/- 45 ng/mL vs. 102 +/- 67 ng/mL, P adjusted for age = 0.001). The mean IGF-1/IGFBP-3 molar ratio was also lower in stroke patients (0.12 +/- 0.07 vs. 0.19 +/- 0.09, P adjusted for age <0.0001). However, there was no relation of hormone levels to either the clinical subtype of stroke or the extent of neurologic impairment. IGF-1 levels were inversely related to poor outcome (mainly death) at 3 and 6 months, independent of other clinical covariates that were highly predictive of outcome, such as age and stroke scale score on admission (hazard ratio for death at 6 months for each 20-ng/mL increase = 0.7; 95% confidence interval: 0.5 to 0.9). An independent association of the molar ratio with death at 3 and 6 months was also found.Low levels of circulating IGF-1 may predict the clinical outcome of stroke in elderly patients.

  View details for DOI 10.1016/j.amjmed.2004.02.049

  View details for Web of Science ID 000223777500004

  View details for PubMedID 15336580

• Epigenetic regulation of the taxol resistance-associated gene TRAG-3 in human tumors CANCER GENETICS AND CYTOGENETICS Yao, X. M., Hu, J. F., Li, T., Yang, Y. W., Sun, Z. H., Ulaner, G. A., Vu, T. H., Hoffman, A. R. 2004; 151 (1): 1-13

  Abstract

  TRAG-3, originally identified as a taxol resistance-associated gene from an ovarian carcinoma cell line, is upregulated in many human tumors. Like many tumor antigens, TRAG-3 mRNA is not detectable or is expressed at very low levels in normal fetal and adult human tissues except for testis, where TRAG-3 mRNA transcripts are detected abundantly. TRAG-3 mRNA is frequently overexpressed in tumors but is rarely detected in adjacent normal tissues. To delineate the transcriptional regulation of this tumor antigen, we cloned and sequenced the TRAG-3 promoter. A 539-base pair fragment upstream of the initiation site, which contains two unusual CT repeat stretches, was sufficient to drive the maximum activity of a luciferase reporter gene. Sodium bisulfite sequencing of genomic DNA revealed that the amount of DNA methylation in exon 2 and in the promoter regions is inversely correlated with gene expression. In normal tissues, TRAG-3 is hypermethylated and is thus transcriptionally silenced. In those tumors where TRAG-3 is actively transcribed, the TRAG-3 promoter and exon 2 are hypomethylated. Treatment of a TRAG-3-silenced cell line H23 with the demethylating reagent 5-aza-cytosine reduced DNA methylation and induced TRAG-3 expression in a dose-dependent manner. These results indicate that DNA demethylation is an important epigenetic mechanism that regulates the TRAG-3 tumor antigen in human tumors.

  View details for DOI 10.1016/j.cancergencyto.2003.08.021

  View details for Web of Science ID 000221502300001

  View details for PubMedID 15120907

• Activating and silencing histone modifications form independent allelic switch regions in the imprinted Gnas gene HUMAN MOLECULAR GENETICS Li, T., Vu, T. H., Yang, Y. W., Hu, J. F., Hoffman, A. R. 2004; 13 (7): 741-750

  Abstract

  Activation and suppression of gene transcription is tightly controlled by epigenetic modifications. The imprinted Gnas1 gene region contains closely juxtaposed maternally expressed (Nesp) and paternally expressed (Nespas, Gnasxl, Exon 1A) transcripts, providing a unique opportunity to study how epigenetic modifications change in nucleosomes from active to silenced promoters. Using 30 polymorphic sites across the Gnas1 gene region in (C57BL/6JxMus spretus) F(1) mice and chromatin immunoprecipitation (ChIP) assays we identified two allelic switch regions (ASRs) that mark boundaries of epigenetic information. We show that activating signals (histone acetylation and methylation of H3 Lys4) and silencing signals (histone methylation of H3 Lys9 and DNA methylation) segregate independently across the ASRs and suggest that these ASRs allow the transcriptional elongation to proceed through the silenced domain of nearby imprinted promoters. We discuss these findings in light of recent progress in the conceptualization of nucleosome remodeling during transcriptional elongation and in the development of histone code.

  View details for DOI 10.1093/hmg/ddh081

  View details for Web of Science ID 000220179900007

  View details for PubMedID 14962976

• Transdermal testosterone gel: pharmacokinetics, efficacy of dosing and application site in hypogonadal men BJU INTERNATIONAL Meikle, A. W., Matthias, D., Hoffman, A. R. 2004; 93 (6): 789-795

  Abstract

  To determine the regimen that would most effectively maintain serum testosterone concentrations in treated hypogonadal men within the normal reference range of 3-11.4 microg/L.Eighteen men aged 24-69 years with either primary or secondary hypogonadism participated in and 16 completed a randomized, six-treatment regimen, three-period (phase), three-way matrix-type crossover study. A 1% and 2% testosterone gel (CP601, Cellegy Pharmaceuticals, Inc., San Francisco, USA) was administered either once or twice daily transdermally at different body sites to determine optimal dosing, application sites, and its pharmacokinetics and tolerability in hypogonadal men. Treatments A-F included 1 g of 1% and 2% gel that was equivalent to 10 or 20 mg of testosterone, applied once or twice daily to the skin of either the thigh or the upper arm. Six men also participated in a study of 3 g of 2% gel that was equivalent to 60 mg of testosterone applied once daily, half on each thigh. Pharmacokinetic variables were calculated for testosterone for each man in each treatment period and the results analysed by anova.In general the higher dose regimens produced higher serum concentrations of testosterone; the 3 g/2% dose was most successful in maintaining serum testosterone within the normal reference range. The average testosterone concentration (C(avg)) was 6.52 microg/L and all men had a C(avg) of > 3.0 microg/L. The prediction of all men achieving a C(avg) of > 3.0 microg/L was 96%. The mean minimum concentration (C(min)) was 3.83 microg/L and half the patients had a C(min) of > 3.0 microg/L. Most men had serum testosterone levels within the normal reference range throughout the 24 h, and the treatment was well tolerated.The 3 g/2% dose applied to the skin daily resulted in serum testosterone in the normal reference range in most hypogonadal men. Dose adjustments to either a lower or higher dose should shift serum testosterone concentration to the desired range in those who do not achieve this range with this dose.

  View details for DOI 10.1111/j.1464-410X.2004.04750.x

  View details for Web of Science ID 000220463300023

  View details for PubMedID 15049991

• Igf2 gene imprinting in preimplantation mouse embryos 52nd Annual Meeting of the Pacific-Coast-Reproductive-Society Littman, E. D., Ulaner, G. A., Vu, T. H., Otero, J., Dasig, D., Lyon, J., Gebhardt, J., Giudice, L. C., Behr, B., Hoffman, A. R. ELSEVIER SCIENCE INC. 2004: S14–S15

  View details for Web of Science ID 000220821600015

• The pharmacokinetic and pharmacodynamic characteristics of a long-acting growth hormone (GH) preparation (Nutropin Depot) in GH-deficient adults JOURNAL OF CLINICAL ENDOCRINOLOGY & METABOLISM Cook, D. M., Biller, B. M., Vance, M. L., Hoffman, A. R., Phillips, L. S., Ford, K. M., Benziger, D. P., Illeperuma, A., Blethen, S. L., Attie, K. M., Dao, L. N., Reimann, J. D., Fielder, P. J. 2002; 87 (10): 4508-4514

  Abstract

  A pharmacokinetic-pharmacodynamic study of a long-acting GH [Nutropin Depot; somatropin (rDNA origin) for injectable suspension] was performed in 25 patients with adult GH deficiency. Single doses of 0.25 mg/kg and 0.5 mg/kg, based on ideal body weight, were administered sc. After either dose, serum GH concentrations rose rapidly in both sexes. In men, the lower dose maintained serum IGF-I levels within 1 SD of the mean for age and sex for 14-17 d; the higher dose raised IGF-I levels 2 SD above the mean. In most women, all of whom were receiving oral estrogen, the lower dose did not normalize IGF-I levels; the higher dose maintained IGF-I near the mean for approximately 14 d. Increases in IGF binding protein-3 and acid-labile subunit levels were observed in both sexes; however, a sex-related difference was not obvious. Fasting glucose and insulin concentrations were transiently elevated in men receiving the higher dose. Patients tolerated the injections well. We concluded that a single injection of Nutropin Depot at these doses in patients with adult GH deficiency increased serum IGF-I to within normal limits for 14-17 d. Estrogen-treated women required approximately twice the dose needed in men to produce comparable IGF-I concentrations.

  View details for DOI 10.1210/jc.2002-020480

  View details for Web of Science ID 000178649800018

  View details for PubMedID 12364427

• An imprinted PEG1/MEST antisense expressed predominantly in human testis and in mature spermatozoa JOURNAL OF BIOLOGICAL CHEMISTRY Li, T., Vu, T. H., Lee, K. O., Yang, Y. W., Nguyen, C. V., Bui, H. Q., Zeng, Z. L., Nguyen, B. T., Hu, J. F., Murphy, S. K., Jirtle, R. L., Hoffman, A. R. 2002; 277 (16): 13518-13527

  Abstract

  PEG1 (or MEST) is an imprinted gene located on human chromosome 7q32 that is expressed predominantly from the paternal allele. In the mouse, Peg1/Mest is associated with embryonic growth and maternal behavior. Human PEG1 is transcribed from two promoters; the transcript from promoter P1 is derived from both parental alleles, and the transcript from P2 is exclusively from the paternal allele. We characterized the P1 and P2 transcripts in various normal and neoplastic tissues. In the normal tissues, PEG1 was transcribed from both promoters P1 and P2, whereas in six of eight neoplastic tissues, PEG1 was transcribed exclusively from promoter P1. Bisulfite sequencing demonstrated high levels of CpG methylation in the P2 region of DNA from a lung tumor. In the region between P1 and P2, we identified a novel transcript, PEG1-AS, in an antisense orientation to PEG1. PEG1-AS is a spliced transcript and was detected as a strong 2.4-kilobase band on a Northern blot. PEG1-AS and PEG1 P2-sense transcript were expressed exclusively from the paternal allele. Fragments of DNA from within the 1.5-kilobase region between PEG1-AS and the P2 exon were ligated to a pGL3 luciferase reporter vector and transfected into NCI H23 cells. This DNA exhibited strong promoter activity in both the sense and antisense directions, indicating that PEG1-AS and P2 exon share a common promoter region. Treatment of the transfected DNA fragments with CpG methylase abolished the promoter activity. Of interest, PEG1-AS was expressed predominantly in testis and in mature motile spermatozoa, indicating a possible role for this transcript in human sperm physiology and fertilization.

  View details for DOI 10.1074/jbc.M200458200

  View details for Web of Science ID 000175096000025

  View details for PubMedID 11821432

• Growth hormone (GH) and insulin-like growth factor-1 (IGF-1) in the elderly: Clinical trial results ARCHIVES OF GERONTOLOGY AND GERIATRICS Ceda, G. P., Dall'Aglio, E., Salimbeni, I., Rocci, A., Corradi, F., Mazzoni, S., Greco, F., Ridolo, E., Ceresini, G., Banchini, A., Valenti, G., Hoffman, A. R. 2002: 81-92

  View details for Web of Science ID 000202846600011

  View details for PubMedID 14764378

• One year of insulin-like growth factor I treatment does not affect bone density, body composition, or psychological measures in postmenopausal women JOURNAL OF CLINICAL ENDOCRINOLOGY & METABOLISM Friedlander, A. L., Butterfield, E., Moynihan, S., Grillo, J., Pollack, M., Holloway, L., Friedman, L., Yesavage, J., Matthias, D. F., Lee, S., Marcus, R., Hoffman, A. R. 2001; 86 (4): 1496-1503

  Abstract

  The activity of the hypothalamic-GH-insulin-like growth factor I (hypothalamic-GH-IGF-I) axis declines with age, and some of the catabolic changes of aging have been attributed to the somatopause. The purpose of this investigation was to determine the impact of 1 yr of IGF-I hormone replacement therapy on body composition, bone density, and psychological parameters in healthy, nonobese, postmenopausal women over 60 yr of age. Subjects (n = 16, 70.6 +/- 2.0 yr, 71.8 +/- 2.8 kg) were randomly assigned to either the self-injection IGF-I (15 microg/kg twice daily) or placebo group and were studied at baseline, at 6 months, and at 1 yr of treatment. There were no significant differences between the IGF-I and placebo groups in any of the measured variables at baseline. Fasting blood IGF-I levels were significantly elevated above baseline values (65.6 +/- 11.9 ng/mL) at 6 months (330.0 +/- 52.8) and 12 months (297.7 +/- 40.8) in the IGF-I treated group but did not change in the placebo subjects. Circulating levels of IGF-binding protein-1 and -3 were unaffected by the IGF-I treatment. Bone mineral density of the forearm, lumbar spine, hip, and whole body [as measured by dual-energy x-ray absorptiometry (DXA)] did not change in either group. Similarly, there was no difference in DXA-measured lean mass, fat mass, or percent body fat throughout the treatment intervention. Muscle strength values (grip, bench press, leg press), blood lipid parameters (cholesterol, high-density lipoprotein, low-density lipoprotein, triglycerides), and measures of postmeal glucose disposal were not altered by IGF-I treatment, although postmeal insulin levels were lower in the IGF-I subjects at 12 months. IGF-I did not affect bone turnover markers (osteocalcin and type I collagen N-teleopeptide), but subjects who were taking estrogen had significantly lower turnover markers than subjects who were not on estrogen at baseline, 6 months, and 12 months. Finally, the psychological measures of mood and memory were also not altered by the intervention. Despite the initial intent to recruit additional subjects, the study was discontinued after 16 subjects completed the protocol, because the preliminary analyses above indicated that no changes were occurring in any outcome variables, regardless of treatment regimen. Therefore, we conclude that 1 yr of IGF-I treatment, at a dose sufficient to elevate circulating IGF-I to young normal values, is not an effective means to alter body composition or blood parameters nor improve bone density, strength, mood, or memory in older women.

  View details for Web of Science ID 000168243000010

  View details for PubMedID 11297574

• Recombinant human growth hormone, but not insulin-like growth factor-I, enhances central fat loss in postmenopausal women undergoing a diet and exercise program HORMONE AND METABOLIC RESEARCH Taaffe, D. R., Thompson, J. L., Butterfield, G. E., Hoffman, A. R., Marcus, R. 2001; 33 (3): 156-162

  Abstract

  We examined the effect of recombinant human growth hormone (rhGH) and/or recombinant human insulin-like growth factor-I (rhIGF-l) on regional fat loss in postmenopausal women undergoing a weight loss regimen of diet plus exercise. Twenty-seven women aged 59-79 years, 20-40% above ideal body weight, completed a 12-week program consisting of resistance training 2 days/week and walking 3 days/week, while consuming a diet that was 500 kcal/day less than that required for weight maintenance. Participants were randomly assigned in a double-blind fashion to receive rhGH (0.025 mg/kg BW/day; n = 7), rhIGF-I (0.015 mg/kg BW/day; n = 7), rhGH + rhIGF-I (n = 6), or placebo (PL; n = 7). Regional and whole body fat mass were determined by dual X-ray absorptiometry. Body fat distribution was assessed by the ratios of trunk fat-to-limb fat (TrF/LimbF) and trunk fat-to-total fat (TrF/TotF). Limb and trunk fat decreased in all groups (p < 0.01). For both ratios of fat distribution, the rhGH treated group experienced an enhanced loss of truncal compared to peripheral fat (p < 0.01), with no significant change for those administered rhIGF-I or PL. There was no association between change in fat distribution and indices of cardiovascular disease risk as determined by serum lipidilipoprotein levels and maximal aerobic capacity. These results suggest that administration of rhGH facilitates a decrease in central compared to peripheral fat in older women undertaking a weight loss program that combines exercise and moderate caloric restriction, although no beneficial effects are conferred to lipid/lipoprotein profiles. Further, the effect of rhGH is not enhanced by combining rhGH with rhIGF-I administration. In addition, rhIGF-I does not augment the loss of trunk fat when administered alone.

  View details for Web of Science ID 000168638500007

  View details for PubMedID 11355749

• Comparative genome analysis of the mouse imprinted gene IMPACT and its nonimprinted human homolog IMPACT: Toward the structural basis for species-specific imprinting GENOME RESEARCH Okamura, K., Hagiwara-Takeuchi, Y., Li, T., Vu, T. H., Hirai, M., Hattori, M., SAKAKI, Y., Hoffman, A. R., Ito, T. 2000; 10 (12): 1878-1889

  Abstract

  Mouse Impact is a paternally expressed gene encoding an evolutionarily conserved protein of unknown function. Here we identified IMPACT, the human homolog of Impact, on chromosome 18q11. 2-12.1, a region syntenic to the mouse Impact locus. IMPACT was expressed biallelically in brain and in various tissues from two informative fetuses and in peripheral blood from an informative adult. To reveal the structural basis for the difference in allelic expression between the two species, we elucidated complete genome sequences for both mouse Impact ( approximately 38 kb) and human IMPACT ( approximately 30 kb). Sequence comparison revealed that the two genes share a well-conserved exon-intron organization but bear significantly different CpG islands. The mouse island lies in the first intron and contains characteristic tandem repeats. Furthermore, this island serves as a differentially methylated region (DMR) consisting of a hypermethylated maternal allele and an unmethylated paternal allele. Intriguingly, this intronic island is missing from the nonimprinted human IMPACT, whose sole CpG island spans the first exon, lacks any apparent repeats, and escapes methylation on both chromosomes. These results suggest that the intronic DMR plays a role in the imprinting of Impact.

  View details for Web of Science ID 000165833900006

  View details for PubMedID 11116084

• Time-dependent effects of intermittent hydrostatic pressure on articular chondrocyte type II collagen and aggrecan mRNA expression JOURNAL OF REHABILITATION RESEARCH AND DEVELOPMENT Smith, R. L., Lin, J., Trindade, M. C., Shida, J., KAJIYAMA, G., Vu, T., Hoffman, A. R., van der Meulen, M. C., Goodman, S. B., Schurman, D. J., Carter, D. R. 2000; 37 (2): 153-161

  Abstract

  The normal loading of joints during daily activities causes the articular cartilage to be exposed to high levels of intermittent hydrostatic pressure. This study quantified effects of intermittent hydrostatic pressure on expression of mRNA for important extracellular matrix constituents. Normal adult bovine articular chondrocytes were isolated and tested in primary culture, either as high-density monolayers or formed aggregates. Loaded cells were exposed to 10 MPa of intermittent hydrostatic pressure at a frequency of 1 Hz for periods of 2, 4, 8, 12, and 24 hrs. Other cells were intermittently loaded for a period of 4 hrs per day for 4 days. Semiquantitative reverse transcription polymerase chain reaction assays were used to assess mRNA signal levels for collagen types II and I and aggrecan. The results showed that type II collagen mRNA signal levels exhibited a biphasic pattern, with an initial increase of approximately five-fold at 4 and 8 hrs that subsequently decreased by 24 hrs. In contrast, aggrecan mRNA signal increased progressively up to three-fold throughout the loading period. Changing the loading profile to 4 hrs per day for 4 days increased the mRNA signal levels for type II collagen nine-fold and for aggrecan twenty-fold when compared to unloaded cultures. These data suggest that specific mechanical loading protocols may be required to optimally promote repair and regeneration of diseased joints.

  View details for Web of Science ID 000165733400008

  View details for PubMedID 10850821

• The insulin-like growth factor axis and plasma lipid levels in the elderly JOURNAL OF CLINICAL ENDOCRINOLOGY & METABOLISM Ceda, G. P., Dall'Aglio, E., Magnacavallo, A., Vargas, N., Fontana, V., Maggio, M., Valenti, G., Lee, P. D., Hintz, R. L., Hoffman, A. R. 1998; 83 (2): 499-502

  Abstract

  The activity of the hypothalamic-GH-insulin-like growth factor (IGF) network declines with age. It has recently been shown that increased cardiovascular mortality occurs in adults with GH deficiency. As hypercholesterolemia is common in GH-deficient adults, and because there is experimental evidence that GH may play a role in regulating plasma cholesterol, we decided to investigate the activity of the GH-IGF axis in an elderly population by measuring serum IGF-I, IGF-II, and IGF-binding protein-3 (IGFBP-3) levels and to study their relationship with blood lipid levels. One hundred and thirty-two elderly subjects, 52 men and 80 women, were studied (age range, 60-91 yr). Men had significantly lower levels of IGFBP-3, high density lipoprotein cholesterol (HDL-C) and apoprotein A1 (ApoA1) compared to the women, whereas IGF-I and IGF-II were only slightly lower. Using linear regression analysis, we observed an inverse relationship of age with IGF-I (r = -0.35; P < 0.001), IGF-II (r = 0.40; P < 0.001), IGFBP-3 (r = 0.52; P < 0.001), body mass index, and lipid levels. Univariate regression analysis showed a strong and positive correlation of both IGF-I and IGFBP-3 with HDL-C and ApoA1. Partial correlation analysis, after adjustment for age and body mass index, showed that IGFBP-3 and IGF-II were still significantly and positively related to HDL-C and ApoA1. Furthermore, a strong association was documented among IGF-I, IGF-II, and IGFBP-3. These data demonstrate that even in an elderly population, further aging is accompanied by a progressive decline in circulating IGF-I, IGF-II, and IGFBP-3, suggesting a continuing diminution of the GH-IGF axis throughout aging. Moreover, the strong correlation between HDL-C and an index of GH secretion, such as IGFBP-3, suggests that GH might play an important role in lipid metabolism in healthy elderly subjects.

  View details for Web of Science ID 000071823900034

  View details for PubMedID 9467564

• Expression and heterozygosity of imprinting IGF-II and H19 in the human chondrosarcoma-derived cells. HCS-2/8 and -2/A Takahashi, K., Vu, T. H., Hattori, T., Nakanishi, T., Hoffman, A. R., Takigawa, M. FEDERATION AMER SOC EXP BIOL. 1997: A937–A937

  View details for Web of Science ID 000073305600957

• Effect of rhGH and rhIGF-I treatment on protein utilization in elderly women AMERICAN JOURNAL OF PHYSIOLOGY-ENDOCRINOLOGY AND METABOLISM Butterfield, G. E., Thompson, J., Rennie, M. J., Marcus, R., Hintz, R. L., Hoffman, A. R. 1997; 272 (1): E94-E99

  Abstract

  To assess the effect of recombinant human growth hormone (rhGH) and recombinant human insulin-like growth factor I (rhIGF-I) on protein utilization, 14 women, age 66-82 yr, were invited to participate in studies of nitrogen balance (n = 14), whole body protein turnover (n = 14), and muscle protein synthesis (n = 8). They were studied both 1 wk before and during the last week of a 1-mo regimen, to which they had been randomly assigned, of either 0.025 mg rhGH/kg once daily or rhIGF-I at 0.015 (low), 0.03 (mid), or 0.06 (high) mg/kg twice daily. Nitrogen balance increased significantly after 1 wk of treatment in all groups (P < 0.05). After 1 mo, the magnitude of this effect had diminished by 50% in the rhGH group but remained elevated throughout the treatment period with all doses of rhIGF-I. Both protein synthesis and breakdown, measured by a primed constant infusion of [15N]glycine, were significantly increased with rhGH (9% and 8%, respectively), low-dose rhIGF-I (4.5% and 4%), and high-dose rhIGF-I (18% and 17%). Net synthesis was significantly increased with rhGH (48%) and high- and mid-dose rhIGF-I (27% and 196%, respectively). Muscle protein synthesis as measured by incorporation of [1-13C]leucine increased significantly with rhGH (50%) and the mid (67%) and high (57%) doses of rhIGF-I. These data show that whole body and muscle protein synthesis are responsive to growth factor stimulation in elderly women.

  View details for Web of Science ID A1997WG56800014

  View details for PubMedID 9038857

• Growth hormone deficiency in adults: Characteristics and response to growth hormone replacement JOURNAL OF PEDIATRICS Lieberman, S. A., Hoffman, A. R. 1996; 128 (5): S58-S60

  Abstract

  Despite adequate adrenal, gonadal, and thyroid hormone replacement, many adults with hypopituitarism have a recognizable syndrome of weakness and diminished sense of well-being, accompanied by alterations in metabolism and body composition, as well as increased mortality. Short-term treatment with human growth hormone improves many of these abnormalities, but a clear improvement in functional status has yet to be demonstrated. Until such an effect is shown, the use of growth hormone replacement in adults with hypopituitarism remains investigational.

  View details for Web of Science ID A1996UK86800013

  View details for PubMedID 8627472

• Lack of effect of recombinant human growth hormone (GH) on muscle morphology and GH-insulin-like growth factor expression in resistance-trained elderly men JOURNAL OF CLINICAL ENDOCRINOLOGY & METABOLISM Taaffe, D. R., JIN, I. H., Vu, T. H., Hoffman, A. R., Marcus, R. 1996; 81 (1): 421-425

  Abstract

  Vastus lateralis muscle samples were obtained by needle biopsy from 18 healthy elderly men (65-82 yr) participating in a double blind, placebo (PL)-controlled trial of recombinant human GH (rhGH) and exercise and assessed for muscle morphology and skeletal muscle tissue expression of GH and insulin-like growth factors (IGFs). Subjects initially underwent progressive resistance training for 14 weeks and were then randomized to receive either rhGH (0.02 mg/kg BW.day, sc) or PL while undertaking a further 10 weeks of training. Muscle samples were obtained at baseline and at 14 and 24 weeks. The mean (+/- SEM) cross-sectional areas of type I and II fibers were similar (type I, 3891 +/- 167 microns2; type II, 3985 +/- 200 microns2) at baseline and increased (P < 0.01) by 16.2 +/- 4.1% and 11.8 +/- 3.8%, respectively, after the initial 14-week training period. After treatment (weeks 14-24), two-way repeated measures ANOVA revealed a main effect of time for type I (P < 0.01) and type II fibers (P < 0.05), but no group effect or interaction. The increase in cross-sectional area for the PL group was significant (P = 0.01) for type I (11.5 +/- 3.6%) and approached significance (P = 0.06) for type II fibers (11.1 +/- 5.6%). For rhGH, the change in type I (6.3 +/- 5.9%) and II (7.1 +/- 5.2%) fiber area was not significant. No apparent change in tissue GH receptor, IGF-I, IGF-I receptor, IGF-II, or IGF-II receptor messenger ribonucleic acids occurred as a result of exercise after the 14-week pretreatment period or after treatment with rhGH or PL. These results indicate that rhGH administration in exercising elderly men does not augment muscle fiber hypertrophy or tissue GH-IGF expression and suggests that deficits in the GH-IGF-I axis with aging do not inhibit the skeletal muscle tissue response to training.

  View details for Web of Science ID A1996TP93900065

  View details for PubMedID 8550787

• EFFECTS OF RECOMBINANT INSULIN-LIKE GROWTH-FACTOR-I AND GROWTH-HORMONE ON BONE TURNOVER IN ELDERLY WOMEN JOURNAL OF BONE AND MINERAL RESEARCH GHIRON, L. J., Thompson, J. L., Holloway, L., Hintz, R. L., Butterfield, G. E., Hoffman, A. R., Marcus, R. 1995; 10 (12): 1844-1852

  Abstract

  We evaluated the effects of recombinant insulin-like growth factor-I (IGF-I) and growth hormone (GH) on calciotropic hormones and bone turnover markers in 16 healthy elderly women 71.9 +/- 1.3 years of age (mean +/- SEM). Subjects consumed a fixed diet providing 1000 mg of calcium and 0.9 g/kg of protein for 10 days before starting baseline 24-h urine and blood collections. Specimens were collected for 6 consecutive days before initiating subcutaneous injections of GH (25 micrograms/kg/day, n = 5) and IGF-I at 60 micrograms/kg b.i.d. (high-dose, n = 5) or at 15 micrograms/kg b.i.d. (low-dose, n = 6) for 28 days. Resorption markers included urine hydroxyproline (OHP), total pyridinolines (PYD), and N-telopeptide; formation markers include osteocalcin, skeletal alkaline phosphatase (sALP), and type I procollagen carboxy-terminal extension peptide (CICP). For each subject, baseline daily turnover markers varied substantially (DV = 16-22%). With GH and high-dose IGF-I, resorption and formation markers increased progressively to maximum levels at day 21. For GH, the increase in day 21 PYD, N-telopeptide, osteocalcin, and CICP was 143, 111, 53, and 81%, respectively (p < 0.96-0.02). For high-dose IGF-I, these increases were 108, 81, 77, and 111% (p < 0.02-0.002). However, with low-dose IGF-I no change was observed in resorption markers while osteocalcin and CICP increased progressively (day 21, % increases = 88 +/- 51, 36 +/- 14). Twenty-four hour urine collections during the last days of baseline and of study drug were taken as six 4 h aliquots. When deoxyPYD was measured on these samples in the low-dose IGF-I group, a significant increase was observed only on the 0800-1200 h aliquot. Serum phosphorus concentrations increased with GH (21.2 +/- 3.3%) and high-dose IGF-I (8.8 +/- 3.6%) by day 21 but actually decreased by day 28 (-9.7 +/- 2.7, p < 0.02) with low-dose IGF-I. Urinary phosphorus excretion decreased with high-dose IGF-I only. Twenty-four hour calcium excretion increased with all treatments. These results indicate that both GH and high-dose IGF-I activate remodeling osteons. By contrast, low-dose IGF-I may directly increase osteoblastic function with only a minimal increase in bone resorption and may therefore provide a useful means to increase bone mass. The results also suggest some of the GH action on renal phosphorus handling represents a direct action of GH on the nephron which does not involve the intermediacy of IGF-I. Finally, even under controlled conditions bone turnover markers exhibit substantial daily variation so that a very large treatment effect will be required for these markers to have clinical utility.

  View details for Web of Science ID A1995TJ13000002

  View details for PubMedID 8619364

• THE EFFECTS OF RECOMBINANT HUMAN INSULIN-LIKE GROWTH-FACTOR-I AND GROWTH-HORMONE ON BODY-COMPOSITION IN ELDERLY WOMEN JOURNAL OF CLINICAL ENDOCRINOLOGY & METABOLISM Thompson, J. L., Butterfield, G. E., Marcus, R., Hintz, R. L., VanLoan, M., Ghiron, L., Hoffman, A. R. 1995; 80 (6): 1845-1852

  Abstract

  The purpose of this study was to determine the effects of recombinant human GH (rhGH; 0.025 mg/kg.day) and one of two doses of recombinant human insulin-like growth factor-I (rhIGF-I; 0.015 and 0.060 mg/kg, twice daily) on body composition in elderly women. Sixteen healthy elderly women (mean age +/- SEM, 71.9 +/- 1.3 yr) were randomly assigned to receive either rhGH (GH; n = 5), low dose rhIGF-I (n = 6), or high dose rhIGF-I (n = 5). A 2-week predrug baseline period was followed by 4 weeks of hormone treatment, with a standardized diet fed throughout. All groups experienced a significant increase in serum IGF-I and IGFBP-3 levels over the treatment period, accompanied by significant decreases in IGF-II (P < 0.05). Fat mass decreased in all groups, with significant increases in lean body mass and nitrogen retention occurring in the high dose IGF and GH groups. Total body water did not change, whereas increases observed in intracellular fluid approached significance (P = 0.06). These anabolic changes were accompanied by numerous negative side-effects in the GH and high dose IGF groups, including headaches, lethargy, joint swelling/pain, and bloatedness. The low IGF dose was well tolerated. These results demonstrate that the administration of rhGH and rhIGF-I for 4 weeks results in anabolic changes in body composition in elderly women.

  View details for Web of Science ID A1995RC75100017

  View details for PubMedID 7539817

• EFFECT OF RECOMBINANT HUMAN GROWTH-HORMONE ON THE MUSCLE STRENGTH RESPONSE TO RESISTANCE EXERCISE IN ELDERLY MEN JOURNAL OF CLINICAL ENDOCRINOLOGY & METABOLISM Taaffe, D. R., Pruitt, L., Reim, J., Hintz, R. L., Butterfield, G., Hoffman, A. R., Marcus, R. 1994; 79 (5): 1361-1366

  Abstract

  Normal aging is characterized by detrimental changes in body composition, muscle strength, and somatotropic function. Reduction in muscle strength contributes to frailty and risk for fracture in the elderly. Although older adults increase muscle strength as a result of resistance exercise training, the strength gains quickly level off, with only modest increases thereafter despite continued training. To investigate whether age-related deficits in the somatotropic axis limit the degree to which muscle strength can improve with resistance training in older individuals, we conducted a double blind, placebo-controlled exercise trial. Eighteen healthy elderly men (65-82 yr) initially underwent progressive weight training for 14 weeks to invoke a trained state. Subjects were then randomized to receive either 0.02 mg/kg BW.day recombinant human GH (rhGH) or placebo, given sc, while undertaking a further 10 weeks of strength training. Sequential measurements were made of muscle strength (one repetition maximum), body composition (dual energy x-ray absorptiometry), and circulating levels of insulin-like growth factor-I (IGF-I) and IGF-binding protein-3. For each exercise, strength increased for both groups (P = 0.0001) through 14 weeks of training, with little improvement thereafter. Increases in muscle strength ranged from 24-62% depending on the muscle group. Baseline plasma IGF-I concentrations were similar in both groups (mean +/- SEM, 106 +/- 9 micrograms/L), approximately half that observed in healthy young adults. In the rhGH group, IGF-I levels increased to 255 +/- 32 micrograms/L at week 15 and 218 +/- 21 micrograms/L at week 24 (P < 0.001). In the placebo group, IGF-I increased slightly to 119 +/- 6 micrograms/L at 24 weeks. IGF-binding protein-3 also increased in the rhGH group (P < 0.05). rhGH had no effect on muscle strength at any time, and no systematic difference in muscle strength was observed between groups throughout the study. Body weight did not change in either group, but lean body mass increased, and fat mass decreased (P < 0.05) in the rhGH group. Supplementation with rhGH does not augment the response to strength training in elderly men. These results suggest that deficits in GH secretion do not underlie the time-dependent leveling off of muscle strength seen with training in the elderly and provide no support for the popular view of GH as an ergogenic aid.

  View details for Web of Science ID A1994PT84400023

  View details for PubMedID 7525633

• INTERACTIONS OF GROWTH-HORMONE AND PARATHYROID-HORMONE IN RENAL PHOSPHATE, CALCIUM, AND CALCITRIOL METABOLISM AND BONE REMODELING IN POSTMENOPAUSAL WOMEN JOURNAL OF BONE AND MINERAL RESEARCH Lieberman, S. A., Holloway, L., Marcus, R., Hoffman, A. R. 1994; 9 (11): 1723-1728

  Abstract

  The mechanisms underlying the effects of recombinant human growth hormone (rhGH) on vitamin D, mineral, and bone metabolism are not known. We examined whether these effects are mediated by parathyroid hormone (PTH) by measuring renal phosphorus (P) and calcium (Ca) handling, serum calcitriol, and markers of bone turnover for 24 h before and 72 h after an infusion of hPTH(1-34) in eight healthy postmenopausal women at baseline and following short-term (1 week) and sustained (5 weeks) rhGH treatment. On short-term rhGH, serum phosphorus and basal TmP/GFR were unaffected, but the fall in TmP/GFR after hPTH infusion was exaggerated (integrated response: -99.2 +/- 22.3 versus -144.1 +/- 15.0 minute-mg/dl, P = 0.0021). Basal calcitriol levels rose from 115 +/- 17 to 163 +/- 16 pM (P = 0.0002), but the increase in calcitriol following hPTH infusion was unaffected by short-term rhGH. The basal Ca excretion index (CEI) rose from 0.054 +/- 0.005 to 0.073 +/- 0.007 mM (P = 0.0095), but markers of bone turnover were unaffected. With sustained rhGH treatment, serum P (1.47 +/- 0.05 mM), basal TmP/GFR (4.29 +/- 0.24 mg/dl), and basal CEI (0.067 +/- 0.005 mM) were elevated compared with control values, and the PTH-induced lowering of TmP/GFR was again enhanced (-158.7 +/- 22.8 minute-mg/dl, P = 0.0021). Basal calcitriol concentrations returned to control levels (108 +/- 10 pM), but the calcitriol response to hPTH remained unchanged. Markers of bone remodeling were elevated with sustained rhGH treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

  View details for Web of Science ID A1994PN66200007

  View details for PubMedID 7863823

• THE INSULIN-LIKE GROWTH-FACTOR-I GENERATION TEST - RESISTANCE TO GROWTH-HORMONE WITH AGING AND ESTROGEN REPLACEMENT THERAPY HORMONE AND METABOLIC RESEARCH Lieberman, S. A., Mitchell, A. M., Marcus, R., Hintz, R. L., Hoffman, A. R. 1994; 26 (5): 229-233

  Abstract

  Circulating IGF-I is primarily regulated by growth hormone, but other factors such as nutritional status may also influence IGF-I secretion. The effects of age, gender, and estrogen replacement on responsiveness of serum IGF-I to GH administration have not been directly studied. The high-affinity circulating GH-binding protein (GHBP) has the same structure as the extracellular domain of the GH receptor and may reflect the sensitivity to GH in humans. To examine these issues, we employed an IGF-I generation test in which a single dose of GH (0.1 mg/kg SQ) was administered to 31 healthy adults comprising five groups: young (20-29 years) males (YM), young females in the follicular phase of the menstrual cycle (YF), older (60-69 years) males (OM), older females not on estrogen replacement (OFN), and older females on oral estrogen replacement (OFE). Blood was sampled for IGF-I and GHBP over 72 hours following GH administration. OM had lower peak IGF-I levels (323 +/- 38 vs. 497 +/- 85 micrograms/l, p = 0.0015) and a lower IGF-I response to GH (delta IGF-I: 187 +/- 33 vs. 293 +/- 57 micrograms/l, p = 0.0085) than YM. OFE had lower basal IGF-I (63 +/- 11 vs. 133 +/- 19 micrograms/l, p = 0.0046), peak IGF-I (174 +/- 28 vs. 400 +/- 40 micrograms/l, p = 0.0015), and delta IGF-I (111 +/- 21 vs. 268 +/- 27 micrograms/l, p = 0.0085) than OFN. IGFBP-3 levels were unchanged 24 hours after GH administration.(ABSTRACT TRUNCATED AT 250 WORDS)

  View details for Web of Science ID A1994NN14400004

  View details for PubMedID 8076905

• ANABOLIC EFFECTS OF RECOMBINANT INSULIN-LIKE GROWTH FACTOR-I IN CACHECTIC PATIENTS WITH THE ACQUIRED-IMMUNODEFICIENCY-SYNDROME JOURNAL OF CLINICAL ENDOCRINOLOGY & METABOLISM Lieberman, S. A., Butterfield, G. E., Harrison, D., Hoffman, A. R. 1994; 78 (2): 404-410

  Abstract

  The loss of lean body mass accompanying acquired immunodeficiency syndrome (AIDS)-associated cachexia is refractory to current modes of therapy. GH and insulin-like growth factor-I (IGF-I) stimulate protein accretion, but resistance to GH action has been reported in malnutrition and infection. We hypothesized that GH resistance occurs in AIDS-associated cachexia, but that treatment with IGF-I would be anabolic. A single injection of GH produced a smaller increase in circulating IGF-I in 21 patients with AIDS compared to that in 23 age-matched controls (141 +/- 15 vs. 194 +/- 15 micrograms/L; P < 0.02), indicating partial GH resistance. Ten subjects received either low or high dose iv recombinant IGF-I 12 h daily for 10 days. Cumulative nitrogen retention was positive for both dosage groups (low dose, 15.42 +/- 6.37 g; high dose, 3.62 +/- 4.15 g), but a significant increase in daily nitrogen retention occurred only in the low dose group on days 2, 4, 5, 6, and 7. Nitrogen balance and protein turnover (estimated by [13C]leucine and [15N] glycine kinetics) during the final 3 days of treatment were unchanged compared to baseline values, confirming the transient nature of the anabolic response. Repeated administration of IGF-I decreased IGF-binding protein-3 levels, producing lower intrainfusion levels of IGF-I and limiting its therapeutic efficacy. The basal metabolic rate increased with high dose IGF-I and may have contributed to the lack of anabolic effect. We conclude that partial GH resistance occurs in AIDS-associated cachexia. Treatment with low dose recombinant IGF-I produces significant, but transient, nitrogen retention. Alternate routes of IGF-I administration or coadministration with GH may prevent attenuation of IGF-I action.

  View details for Web of Science ID A1994MW71700030

  View details for PubMedID 7508949

• INSULIN-LIKE GROWTH-FACTORS (IGFS), IGF BINDING-PROTEINS (IGFBPS) AND IGFBP PROTEASE IN HUMAN UTERINE ENDOMETRIUM - THEIR POTENTIAL RELEVANCE TO ENDOMETRIAL CYCLIC FUNCTION AND MATERNAL-EMBRYONIC INTERACTIONS 3rd International Symposium on Insulin-Like Growth Factors Giudice, L. C., Irwin, J. C., DSUPIN, B. A., DELASFUENTES, L., JIN, I. H., Vu, T. H., Hoffman, A. R. ELSEVIER SCIENCE PUBL B V. 1994: 351–361

  View details for Web of Science ID A1994BB11B00035

• MESSENGER-RNA STRUCTURE, INSITU, AS ASSESSED BY MICROSCOPIC TECHNIQUES MICROSCOPY RESEARCH AND TECHNIQUE Eberwine, J. H., Spencer, C., NEWELL, D., Hoffman, A. R. 1993; 25 (1): 19-28

  Abstract

  The secondary and tertiary structure of RNA, in situ, is thought to be involved in distinct functions such as directing association of the RNA with the cytoskeleton, enzymatic activity of some RNAs, and the control of translation. In situ transcription (IST), a procedure by which cDNA is synthesized in situ, has been used to assess mRNA structure in situ using fixed cells or tissues. Distinct banding patterns were noted for mouse and rat POMC. Unique IST banding patterns were observed when an oligonucleotide complementary to a putative POMC stem-loop structure was used to prime IST. Indeed local changes in banding patterns could be elicited by pharmacological agents which modulate POMC translation. Inhibition of POMC synthesis with NaF or dexamethasone decreased the number of POMC mRNAs in the polysome fractions and increased the intensity of high molecular weight IST-derived bands. Forskolin, a stimulator of POMC synthesis, had the opposite effect. One mechanism by which translational control is thought to occur is by regulation of ribosome movement down the mRNA by specific binding of cytosolic proteins to RNA structure. Cytosolic protein fractions from AtT20 pituitary cells have been shown to specifically bind to the IST-predicted RNA structure. These findings suggest that 1) mRNA structure can be assessed in situ, 2) translation may be altered by the secondary and tertiary structure of mRNAs, and 3) a predicted stem-loop structure exists in situ in the 5'-end of POMC mRNA.

  View details for Web of Science ID A1993KY61700003

  View details for PubMedID 8353304

• GROWTH-HORMONE THERAPY IN THE ELDERLY - IMPLICATIONS FOR THE AGING BRAIN 2ND WORKSHOP ON THE PSYCHONEUROENDOCRINOLOGY OF AGING Hoffman, A. R., Lieberman, S. A., Ceda, G. P. PERGAMON-ELSEVIER SCIENCE LTD. 1992: 327–33

  Abstract

  Growth hormone (GH) secretion declines during normal aging, resulting in lower serum insulin-like growth factor (IGF)-I levels. It has been proposed that many of the catabolic changes seen in normal aging, including osteoporosis and muscle atrophy, are in part caused by the decreased action of the GH-IGF-I axis. In addition, patients with GH deficiency have increased overall cardiovascular mortality. Several investigators have initiated GH treatment for elderly patients with relative hyposomatotropinemia. Initial reports suggest that GH can increase muscle mass, improve exercise tolerance, increase REM sleep and cause an enhanced sense of well-being. The basis for neuropsychiatric changes during GH therapy may be due to a direct CNS action of GH itself, to the increased IGF-I secretion which GH elicits, or to enhanced functioning of peripheral organ systems. Long-term studies will determine whether GH or IGF-I can exert a neurotrophic action in the aging brain.

  View details for Web of Science ID A1992JZ31000006

  View details for PubMedID 1438653

• REGULATION OF INSULIN-LIKE GROWTH FACTOR-BINDING PROTEIN EXPRESSION BY THYROID-HORMONE IN RAT GH3 PITUITARY-TUMOR CELLS ENDOCRINOLOGY Ceda, G. P., Fielder, P. J., Donovan, S. M., Rosenfeld, R. G., Hoffman, A. R. 1992; 130 (3): 1483-1489

  Abstract

  Rat pituitary GH3 tumor cells express GH and insulin-like growth factor-I (IGF-I) mRNAs and possess specific IGF-I and IGF-II receptors which mediate the inhibitory effect of IGF on GH secretion. T3 increases the rate of cell replication and GH gene transcription, and causes an increase in IGF-I binding to cell membranes. Since the IGFs circulate in association with specific binding proteins (IGFBPs) that appear to modulate the access of IGFs to their receptors, we have investigated the effect of T3 treatment on the expression of IGFBPs in GH3 cells. Cells were grown in serum-free defined medium, and IGFBP secretion was determined by Western ligand blotting of conditioned medium after the addition of T3 and/or various peptides for 48-72 h. The conditioned medium of GH3 cells revealed a complex of bands migrating at 40-45 Mr, a pattern typical of rat (r) IGFBP-3. T3 treatment resulted in an increase in rIGFBP-3. IGF-I, IGF-II, and insulin did not alter rIGFBP-3 levels. After concentrating (10-fold) conditioned medium samples, two additional bands at 24K and 28K mol wt were also seen. These bands corresponded in size to rIGFBP-4 (24K) and its glycosylated form (28K). The mRNAs for both rIGFBP-3 and rIGFBP-4 were present in GH3 cells; T3 treatment increased steady state levels of rIGFBP-3 mRNA, but did not affect BP-4 mRNA levels. To learn whether the increased expression of IGFBPs could be responsible for the increased IGF-I binding seen after T3 treatment, [125I]IGF-I was cross-linked to GH3 membranes, and the proteins were separated on a 5-15% gradient sodium dodecyl sulfate-polyacrylamide gel under reducing conditions. T3 treatment induced a large increase in the intensity of bands migrating at 135K and 280K, representing the alpha-subunit of the IGF-I receptor and an incompletely reduced alpha-alpha-dimer, respectively. No membrane-associated IGFBPs were detected. In conclusion, GH3 cells express two IGFBPs, rIGFBP-3 and rIGFBP-4, which are differentially regulated by T3. The increased binding of IGF-I to GH3 cell membranes after T3 treatment indicates that thyroid hormone induces an up-regulation of IGF-I receptors and that the increased IGF-I binding to GH3 membranes is not due to increased expression of membrane-associated IGFBPs.

  View details for Web of Science ID A1992HG16100053

  View details for PubMedID 1371451

• DIFFERENTIAL-EFFECTS OF INSULIN-LIKE GROWTH-FACTOR (IGF)-I AND IGF-II ON THE EXPRESSION OF IGF BINDING-PROTEINS (IGFBPS) IN A RAT NEUROBLASTOMA CELL-LINE - ISOLATION AND CHARACTERIZATION OF 2 FORMS OF IGFBP-4 ENDOCRINOLOGY Ceda, G. P., Fielder, P. J., Henzel, W. J., Louie, A., Donovan, S. M., Hoffman, A. R., Rosenfeld, R. G. 1991; 128 (6): 2815-2824

  Abstract

  The isolation and hormonal regulation of two low molecular weight insulin-like growth factor binding proteins (IGFBPs) present in the conditioned medium (CM) of the rat neuroblastoma cell line B104 cells has been performed. IGFBPs were purified by ZnSO4 precipitation, insulin-like growth factor-I 1IGF-I) affinity chromatography, and reverse phase HPLC. Final isolation and N-terminal analysis was accomplished by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, electroblotting to polyvinylidene difluoride membranes, and sequencing of the bound proteins. Two IGFBPs, with apparent Mr of 28K and 24K were coisolated and sequenced. Both proteins had identical N-terminal sequences and appear to be two forms of IGFBP-4. Treatment of the IGFBPs with endoglycosidase-F caused a shift in the apparent Mr of the 28K IGFBP to 24K. However, there was no change in the apparent Mr of the 24K IGFBP. The data from this study suggest that the IGFBP-4 exists as both a glycosylated and nonglycosylated protein. Treatment of B104 cells with IGF-I increased the expression of both the 24K and 28K IGFBPs and also resulted in the appearance of IGFBP-3 and an unknown IGFBP at 29K. When added to subconfluent cells, IGF-I was also mitogenic in B104 cells. Similar to IGF-I, IGF-II treatment increased cell number and resulted in the appearance of IGFBP-3 and the 29K IGFBP. However, IGF-II treatment resulted in a significant decrease (approximately 50%) in the 24K IGFBP and also decreased the 28K IGFBP. This decrease in the expression of the 24K and 28K IGFBPs was dose-dependent and was blocked by addition of IGF-I to the cells. When an IGF-II receptor antibody was added to the cells it mimicked the effects of IGF-II on B104 cells, suggesting that the inhibitory effects of IGF-II are mediated through the type II IGF receptor. Although both IGF-I and IGF-II affected the amount of the 24K IGFBP in the CM, neither peptide affected the expression of the messenger RNA for the 24K IGFBP. In conclusion, we have isolated two IGFBPs from the CM of B104 cells. Both the 24K and 28K IGFBPs appear to be isoforms of the same protein, and sequence data suggest these proteins are two forms of IGFBP-4. IGF-I increases the expression of both of these IGFBPs, whereas IGF-II decreases their expression.(ABSTRACT TRUNCATED AT 400 WORDS)

  View details for Web of Science ID A1991FN11200020

  View details for PubMedID 1709857

• EFFECTS OF CYTIDINE 5'-DIPHOSPHOCHOLINE ADMINISTRATION ON BASAL AND GROWTH HORMONE-RELEASING HORMONE-INDUCED GROWTH-HORMONE SECRETION IN ELDERLY SUBJECTS ACTA ENDOCRINOLOGICA Ceda, G. P., Ceresini, G., Denti, L., Magnani, D., Marchini, L., Valenti, G., Hoffman, A. R. 1991; 124 (5): 516-520

  Abstract

  The basal and GH-releasing hormone-stimulated secretion of GH declines in the elderly. We tested the ability of cytidine 5'-diphosphocholine, a drug used in the treatment of stroke and Parkinson's disease, to alter GH secretion in 11 healthy elderly volunteers, aged 69-84. Each subject received an iv infusion of 2 g of cytidine 5'-diphosphocholine or normal saline. GHRH and TRH were also administered during cytidine 5'-diphosphocholine infusions. The infusion of cytidine 5'-diphosphocholine induced a 4-fold (p less than 0.05) increase in serum GH levels over basal values. A small increase in GH was seen after GHRH administration. However, the addition of GHRH to the cytidine 5'-diphosphocholine infusion resulted in a GH response which was significantly greater than that seen after GHRH alone; the integrated concentration of GH was more than 2-fold greater in the cytidine 5'-diphosphocholine treated group (706.85 +/- 185.1 vs 248.9 +/- 61.4 micrograms.l-1.(120 min)-1; p = 0.01). The PRL and TSH responses to TRH were not significantly affected by cytidine 5'-diphosphocholine infusion, indicating that dopaminergic mechanisms are not involved. These studies demonstrate that cytidine 5'-diphosphocholine can enhance basal and GHRH-stimulated GH release in the elderly, but the mechanism of action of the drug remains unclear.

  View details for Web of Science ID A1991FM09100004

  View details for PubMedID 2028709

• THE EFFECTS OF AGING ON THE SECRETION OF THE COMMON ALPHA-SUBUNIT OF THE GLYCOPROTEIN HORMONES IN MEN JOURNAL OF THE AMERICAN GERIATRICS SOCIETY Ceda, G. P., Denti, L., Ceresini, G., TORSIGLIERI, W., Hoffman, A. R., Valenti, G. 1991; 39 (4): 353-358

  Abstract

  To investigate the effects of aging on the secretion of the common alpha-subunit of the glycoprotein hormones, we measured basal levels of luteinizing hormone (LH), testosterone (T) and alpha-subunit in 176 normal men aged 19 to 89 years. In addition, in two groups of young (less than 65 years; n = 25) and old (greater than 65 years; n = 15) subjects, the effects of luteinizing hormone-releasing hormone (LHRH) on LH and alpha-subunit secretion were determined. Age-related increases in serum alpha-subunit and LH were noted only in the oldest men while T levels decreased progressively with advancing age. LHRH stimulation resulted in significantly greater secretion of alpha-subunit in the old subjects while no difference in LH release between young and old men was observed. Moreover, there was a delay to peak LH and alpha-subunit levels after LHRH in the old subjects. These data suggest that the aging process in males involves deficits in both testicular and gonadotroph functions as demonstrated by (1) the relative hypogonadotropic hypogonadism seen until the ninth decade; (2) the hypergonadotropic hypogonadism apparent in men greater than 80 years; (3) the delay in the timing of peak responses of LH and alpha-subunit after LHRH administration; and (4) the disproportionate increase in the secretion of alpha subunit relative to intact LH.

  View details for Web of Science ID A1991FE94900004

  View details for PubMedID 1707071

• SECRETION OF ALPHA-SUBUNIT AND INTACT GONADOTROPINS AFTER SURGICAL AND CHEMICAL CASTRATION HORMONE AND METABOLIC RESEARCH Ceda, G. P., Denti, L., Ceresini, G., Cortellini, P., Banchini, A., Frattini, A., Hoffman, A. R., Valenti, G. 1990; 22 (3): 179-182

  Abstract

  In order to investigate the regulatory mechanisms involved in the secretion of glycoprotein hormones, we studied the secretory patterns of LH, FSH and alpha-subunit in hypogonadal men. Three groups of patients with carcinoma of the prostate were studied both before and 15 days after orchiectomy, or the initiation of ketoconazole or LHRH analog therapy. There were significant increases (P less than 0.01) in LH and alpha-subunit levels in the patients treated with orchiectomy and ketoconazole, but FSH levels increased only in the orchiectomized patients. After LHRH analog treatment, LH levels were significantly decreased when assayed with an immunoradiometric assay method which does not cross-react with alpha-subunit. FSH values were significantly lower than pretreatment levels, while alpha-subunit levels remained significantly elevated throughout the study period. These results demonstrate that after both chemical (ketoconazole) and surgical castration, the secretion of alpha subunit follows a pattern which is tightly correlated with that of LH but not of FSH. However, after LHRH analog treatment, alpha-subunit appears to be the sole secretory product of the gonadotroph.

  View details for Web of Science ID A1990CX72300010

  View details for PubMedID 1693131

• CALCITONIN INHIBITION OF GROWTH HORMONE-RELEASING HORMONE-INDUCED GH SECRETION IN NORMAL MEN ACTA ENDOCRINOLOGICA Ceda, G. P., Denti, L., Ceresini, G., Rastelli, G., Dotti, C., Cavalieri, S., Valenti, G., Hoffman, A. R. 1989; 120 (4): 416-422

  Abstract

  Calcitonin has been shown to modulate pituitary hormone secretion in a variety of ways. In this study we examined the effects of a salmon calcitonin infusion on GHRH-induced GH secretion in 5 normal men. In addition, in vitro experiments were performed using primary cultures of rat anterior pituitary cells in order to examine whether there is a direct pituitary effect of CT. Infusion of CT significantly blunted the GH response to GHRH in all subjects without affecting basal GH secretion or plasma calcium levels. Infusion of CT was accompanied by significant increases in ACTH, beta-endorphin, cortisol and free fatty acid levels, and by a significant decrease in serum insulin levels. The addition of CT to primary cultures of rat pituitary cells did not alter basal or stimulated secretion of GH or ACTH. These results indicate that: 1) CT blunts the GH response to GHRH; 2) CT infusion results in the stimulation of the hypothalamic-pituitary-adrenal axis, and 3) this effect is probably exerted at the hypothalamic level, since no direct activity of CT was documented in vitro on either GH or ACTH secretion.

  View details for Web of Science ID A1989U390000003

  View details for PubMedID 2541589

• INTERACTION OF IGF WITH THE HYPOTHALAMUS AND PITUITARY SYMP ON MOLECULAR AND CELLULAR BIOLOGY OF INSULIN-LIKE GROWTH FACTORS AND THEIR RECEPTORS Rosenfeld, R. G., OCRANT, I., Valentino, K. L., Hoffman, A. R. PLENUM PRESS DIV PLENUM PUBLISHING CORP. 1989: 39–56

  View details for Web of Science ID A1989BQ28G00004

• ABERRANT PRODUCTION AND REGULATION OF PROOPIOMELANOCORTIN-DERIVED PEPTIDES IN ECTOPIC CUSHINGS-SYNDROME HORMONE AND METABOLIC RESEARCH Roth, K. A., NEWELL, D. C., Dorin, R. I., Eberwine, J. H., Hoffman, A. R. 1988; 20 (4): 225-229

  Abstract

  A 64 year old woman with a pancreatic islet cell tumor developed Cushing's syndrome. Glucocorticoid secretion did not decrease after low or high dose dexamethasone administration, and the Cushing's syndrome was cured by removal of tumor tissue. Immunohistochemistry and radioimmunoassays revealed the presence of immunoreactive ACTH, beta-endorphin and alpha-MSH in the tumor cells. Gel-permeation chromatography confirmed that beta-endorphin was the predominant opioid peptide produced by the tumor. The tumor was shown to contain a single 1.2 kilobase RNA species which hybridized to a 32P human POMC-cDNA; this POMC RNA was identical in size to that isolated from a normal human pituitary. In dispersed monolayer culture, CRF failed to elicit ACTH release from the tumor cells, but dexamethasone caused a paradoxical increase in ACTH secretion in vitro. This study demonstrates that aberrant regulation of POMC synthesis and peptide processing can be seen in tumors which synthesize a POMC RNA identical in size to that made in the pituitary gland.

  View details for Web of Science ID A1988N470200007

  View details for PubMedID 2456259

• THYROID-HORMONE UPREGULATES INSULIN-LIKE GROWTH FACTOR-I RECEPTORS IN CULTURED RAT PITUITARY-CELLS GEARY, E. S., Lim, M. L., Ceda, G. P., Rosenfeld, R. G., Hoffman, A. R. SLACK INC. 1988: A152–A152

  View details for Web of Science ID A1988L516800893

• CHARACTERIZATION OF OPIOID-PEPTIDES IN HUMAN THYROID MEDULLARY CARCINOMA CANCER Roth, K. A., Bensch, K. G., Hoffman, A. R. 1987; 59 (9): 1594-1598

  Abstract

  A thyroid medullary carcinoma from a man with the multiple endocrine neoplasia syndrome Type IIB was examined for the presence of opioid peptides. The tumor contained peptides derived from all three opioid precursors: pro-opiomelanocortin (POMC), pro-dynorphin, and pro-enkephalin. The tissue concentrations of the various opioid peptides varied considerably. beta-Endorphin, a POMC-derived peptide, was present in concentrations between 9 to 12 pmoles/g tissue; 8 pmoles/g tissue of alpha-neo-endorphin, a pro-dynorphin-derived product, were seen, whereas the pro-enkephalin-associated peptides were present in much lower concentrations (0.6-2.1 pmoles/g tissue). Immunohistochemical studies showed scattered opioid-positive cells in the tumor tissue and in two other thyroid medullary carcinomas. These data demonstrate that malignant neuroendocrine tumors may contain peptides derived from all three families of the endogenous opioids.

  View details for Web of Science ID A1987G892200011

  View details for PubMedID 3828959

• THE GROWTH-HORMONE (GH)-RELEASING HORMONE (GHRH)-GH-SOMATOMEDIN AXIS - EVIDENCE FOR RAPID INHIBITION OF GHRH-ELICITED GH RELEASE BY INSULIN-LIKE GROWTH FACTOR-I AND FACTOR-II ENDOCRINOLOGY Ceda, G. P., Davis, R. G., Rosenfeld, R. G., Hoffman, A. R. 1987; 120 (4): 1658-1662

  Abstract

  Hypothalamic-pituitary-end-organ axes are frequently controlled by long loop negative feedback homeostatic mechanisms. Insulin-like growth factor I (IGF-I), IGF-II, and insulin receptors have recently been described in normal and neoplastic rat and acromegalic human pituitary cells, a finding which suggests the possibility that somatomedins might exert feedback at the level of the anterior pituitary. To study the kinetics of this feedback response, we used perifused dispersed rat anterior pituitary cells to learn if somatomedins or insulin could inhibit GH-releasing hormone (GHRH)-stimulated GH secretion. Cells were exposed to hourly boluses of 1 nM GHRH with or without varying doses of IGF or insulin. IGF-I inhibited GHRH-elicited GH release with an IC50 of 6.5 nM; maximal inhibition (approximately 67%) was achieved with 10 nM IGF-I. IGF-II was a less potent hormone, with 10 nM inhibiting about 30% of GHRH-stimulated GH release. Slight inhibition of stimulated GH release (less than 15%) was seen when cells were treated with insulin, but only when doses of insulin of 10 nM or more were used. In conclusion, nanomolar concentrations of IGF-I and IGF-II inhibited GHRH-elicited GH release from perifused rat pituitary cells in a dose-dependent manner; and insulin was not an effective inhibitor of stimulated GH release at physiological peptide concentrations. In conjunction with our previous findings that the concentrations of IGF-I and IGF-II receptors greatly exceed that of insulin receptors on normal rat pituitary cells, we hypothesize that the GH-inhibiting action of high dose insulin is mediated through an IGF receptor.

  View details for Web of Science ID A1987G571000059

  View details for PubMedID 3104015

• GLUCOCORTICOID MODULATION OF GROWTH-HORMONE SECRETION INVITRO - EVIDENCE FOR A BIPHASIC EFFECT ON GH-RELEASING HORMONE MEDIATED RELEASE ACTA ENDOCRINOLOGICA Ceda, G. P., Davis, R. G., Hoffman, A. R. 1987; 114 (4): 465-469

  Abstract

  Glucocorticoids have been shown to have both stimulatory and suppressive effects on GH secretion in vitro and in vivo. In order to study the kinetics of glucocorticoid action on the somatotrope, cultured rat pituitary cells were exposed to dexamethasone for varying periods of time. During short-term incubations (less than or equal to 4 h), dexamethasone inhibited GHRH and forskolin-elicited GH secretion, but during longer incubation periods, the glucocorticoid enhanced both basal and GHRH-stimulated GH release. The inhibitory effect of brief dexamethasone exposure was also seen in cells which previously had been exposed to dexamethasone. In addition, growth hormone secretion from cultured rat and human somatotropinoma cells was inhibited by a brief exposure to dexamethasone. Thus, the nature of glucocorticoid action on the isolated cultured somatotrope is biphasic, with brief exposure inhibiting, and more prolonged exposure stimulating GH secretion.

  View details for Web of Science ID A1987G735800001

  View details for PubMedID 3107294

• ACROMEGALY AND PHEOCHROMOCYTOMA - A MULTIPLE ENDOCRINE SYNDROME CAUSED BY A PLURIHORMONAL ADRENAL-MEDULLARY TUMOR JOURNAL OF CLINICAL ENDOCRINOLOGY & METABOLISM Roth, K. A., Wilson, D. M., Eberwine, J., Dorin, R. I., Kovacs, K., Bensch, K. G., Hoffman, A. R. 1986; 63 (6): 1421-1426

  Abstract

  A 42-yr-old man with congestive heart failure and diabetes mellitus was found to have acromegaly and a pheochromocytoma. Serum GH-releasing hormone (GHRH) levels were elevated (2.34 ng/dl; normal, less than 0.02 ng/dl), suggesting that the acromegaly was caused by ectopic secretion of GHRH. Postmortem examination revealed that the right adrenal gland contained a pheochromocytoma in which GHRH was demonstrated by immunohistochemical studies. Gel permeation chromatography combined with the use of two GHRH antisera showed that GHRH-(1-44)-NH2 was a predominant form of the hormone. When the RNA from the tumor was extracted and analyzed by Northern gel blotting, two mRNA species were identified, with transcripts corresponding to 1600 and 780 base pairs. The pituitary gland was enlarged, but no distinct adenoma was found. Diffuse and nodular hyperplasia of somatotrophs in some areas resembling adenoma was identified on histological examination. These findings indicate that GH excess accompanied by somatotroph hyperplasia and acromegaly were secondary to a pheochromocytoma which secreted not only catecholamines but also GHRH.

  View details for Web of Science ID A1986E916800028

  View details for PubMedID 3097056

• MILK-ALKALI SYNDROME IN PATIENTS TREATED WITH CALCIUM-CARBONATE AFTER CARDIAC TRANSPLANTATION ARCHIVES OF INTERNAL MEDICINE Kapsner, P., LANGSDORF, L., Marcus, R., Kraemer, F. B., Hoffman, A. R. 1986; 146 (10): 1965-1968

  Abstract

  Heart and heart-lung transplant recipients at Stanford (Calif) University Medical Center were routinely prescribed long-term calcium carbonate antacid therapy to aid in the prevention of peptic ulcer disease and osteoporosis associated with glucocorticoid immunosuppressive therapy. Patients consumed 4 to more than 10 g/d of elemental calcium. Since calcium carbonate also provides the essential ingredients for the development of the milk-alkali syndrome, the laboratory flow sheets of 297 heart and heart-lung transplant recipients were reviewed to examine the incidence of hypercalcemia. Sixty-five patients developed significant hypercalcemia after transplantation. Thirty-one patients were alkalotic at the time of hypercalcemia; 37 had impairment in renal function. It is likely that most of these patients had the milk-alkali syndrome. While most patients became eucalcemic by discontinuing calcium carbonate therapy, intravenous hydration and forced diuresis were used to treat severe cases. It is possible that the incidence of the milk-alkali syndrome will increase with the current popularity of prescribing calcium carbonate for the prevention and treatment of osteoporosis.

  View details for Web of Science ID A1986E259300014

  View details for PubMedID 3532984

• DIMINISHED PITUITARY-RESPONSIVENESS TO GROWTH HORMONE-RELEASING FACTOR IN AGING MALE-RATS ENDOCRINOLOGY Ceda, G. P., Valenti, G., BUTTURINI, U., Hoffman, A. R. 1986; 118 (5): 2109-2114

  Abstract

  The pattern of GH secretion undergoes substantial changes in the aging rat, resulting in decreased daily secretion of GH. In this study, the pituitary responsiveness to GH-releasing factor (GRF) was examined in young (2- to 5-month old) and aging (14- to 18-month old) male rats. In vivo studies were performed under sodium pentobarbital anesthesia. After injection of 250 ng GRF/100 g BW, young rats experienced more GH secretion [peak level, 544.5 +/- 209.5 (+/- SEM) ng/ml] than did 18-month-old rats (89.3 +/- 13.7 ng/ml). To investigate the locus of this insensitivity to GRF, anterior pituitary cells from young and aging rats were dispersed and placed in primary culture. While basal GH secretion from the cultured pituitary cells was similar in the two groups (49.7 +/- 3.5 vs. 47.8 +/- 2.7 ng/ml X 4 h for the 2- and 18-month old rats, respectively), the GH-releasing ability of GRF was partially but significantly impaired in cells derived from both 14- and 18-month old rats; 100 nM GRF stimulated the release of 96.7 +/- 1.8 ng/ml X 4 h in the 18-month old rats as opposed to 115.0 +/- 6.0 (P less than 0.05) ng/ml X 4 h in the 2-month-old rats. Since GRF stimulates GH release through the activation of adenylate cyclase, intracellular cAMP levels were measured in the cultured pituitary cells. GRF stimulated 65% less intracellular cAMP accumulation in the 18-month-old rats. In 14-month-old rats, the ability of forskolin and (Bu)2 cAMP to release GH was impaired, while phorbol ester-elicited GH secretion was unchanged. In conclusion, the GH response to GRF is blunted in aging rats. While much of the insensitivity to GRF may be mediated by the increased somatostatin tone reported in aging rats, a diminished pituitary cAMP response to GRF may also be an important etiological factor in the hyposomatotropinemia of the aging male rat.

  View details for Web of Science ID A1986C003400055

  View details for PubMedID 3009151

• GLUCOCORTICOID MODULATION OF CORTICOTROPIN-RELEASING FACTOR DESENSITIZATION IN CULTURED RAT ANTERIOR-PITUITARY-CELLS ENDOCRINOLOGY Ceda, G. P., Hoffman, A. R. 1986; 118 (1): 58-62

  Abstract

  The ability of ovine corticotropin-releasing factor (CRF) to stimulate both ACTH release and intracellular cAMP accumulation is rapidly and reversibly desensitized when rat anterior pituitary cells are cultured in the absence of added glucocorticoids. Since this desensitization has not been readily apparent in vivo, where initial CRF exposure results in high levels of ambient glucocorticoids, we examined the effect of glucocorticoids on the desensitization process in vitro. Rat anterior pituitary cells were cultured for 3-5 days in the absence of added steroid hormones. Dexamethasone was then added to some culture wells 24 h before the desensitization experiment began. Desensitization of CRF was achieved by preincubating the cells for 4 h with varying concentrations (10(-11)-10(-7) M) of ovine CRF, washing the cells with medium alone, and then reexposing the cells to CRF. In the absence of glucocorticoid, the ED50 for CRF desensitization (the preincubation dose causing 50% desensitization of subsequent ACTH release) was 3 X 10(-10) M, but cells that had been preexposed to dexamethasone desensitized less readily. With concentrations of dexamethasone of 10(-8) M or greater, no desensitization occurred. When cells were incubated in the absence of added glucocorticoids, CRF-stimulated intracellular cAMP accumulation was diminished by prior exposure to CRF. No decrease in intracellular cAMP accumulation was seen in those cells that had been preincubated with dexamethasone, however. Similar changes in CRF desensitization of ACTH release were observed when cells were incubated with corticosterone, but not with 10(-8) M testosterone, progesterone, aldosterone, or estradiol. These data demonstrate that glucocorticoids profoundly alter the development of CRF desensitization in vitro and suggest that high ambient glucocorticoid concentrations prevent the development of substantial CRF desensitization in vivo.

  View details for Web of Science ID A1986AWR7000009

  View details for PubMedID 3000748

• INSULIN AND INSULIN-LIKE GROWTH-FACTOR (SOMATOMEDIN) RECEPTORS ON CLONED RAT PITUITARY-TUMOR CELLS ENDOCRINOLOGY Rosenfeld, R. G., Ceda, G., Cutler, C. W., DOLLAR, L. A., Hoffman, A. R. 1985; 117 (5): 2008-2016

  Abstract

  Specific receptors for insulin and the somatomedin peptides insulin-like growth factors I and II (IGF-I and IGF-II) have been characterized on three separate cloned strains of rat pituitary tumor cells (GH3, GH1, and GC). Binding of 125I-labeled peptides was time, temperature, and pH dependent for all three cell lines. Specific binding of [125I]insulin, which was extremely low in normal rat adenohypophyseal cells, was demonstrable for all three lines, with the Kd for the high affinity receptor ranging from 10(-10) to 4 X 10(-10) M/liter. A specific high affinity IGF-I receptor was also identified, with a Kd of approximately 10(-9) M/liter. IGF-II and insulin were, respectively, 10% and 1% as potent as IGF-I in competing for this receptor. When [125I]insulin and [125I]IGF-I were cross-linked to GH3 cells with disuccinimidyl suberate, followed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, both receptors were found to have an apparent mol wt greater than 300,000 in the unreduced state, with subunits of apparent mol wt 125,000 after reduction. A third discrete receptor, which bound [125I]IGF-II, was also identified on all three cell lines. IGF-I was only 10% as potent as IGF-II at displacing [125I]IGF-II, and insulin was virtually unreactive. When [125I]IGF-II was cross-linked to GH3 cells and analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, two receptors were identified. One had an apparent mol wt of 205,000 unreduced and 250,000 upon reduction, and presumably represents the type II receptor. Additionally, a band was observed at an apparent mol wt greater than 300,000 unreduced and 125,000 upon reduction, probably representing IGF-II binding to the IGF-I or insulin receptor. The presence of specific high affinity receptors for insulin, IGF-I, and IGF-II in these transformed cell lines is consistent with previous observations in normal rat and human pituitary cells and suggests a role for these peptides in the modulation of pituitary function.

  View details for Web of Science ID A1985ASW3000039

  View details for PubMedID 2995005

• GROWTH HORMONE-RELEASING FACTOR DESENSITIZATION IN RAT ANTERIOR-PITUITARY CELLS-INVITRO ENDOCRINOLOGY Ceda, G. P., Hoffman, A. R. 1985; 116 (4): 1334-1340

  Abstract

  Preincubation of rat pituitary cells in primary culture with rat GH-releasing factor (rGRF) resulted in substantial desensitization to subsequent GRF stimulation. rGRF-directed GH release and intracellular cAMP accumulation decreased in the desensitized cells. Whereas prior treatment of rat pituitary cells caused partial depletion of intracellular GH levels, diminished cellular reserves could not entirely account for the decreased GH release. Cells that had been preexposed to 10 nM rGRF for 4 h demonstrated at 30-50% depletion of intracellular GH; subsequent stimulation of those cells with 10 nM rGRF elicited GH release which was only 5% of that seen in cells that were not desensitized [control, 112 +/- 3.2 ng/well (+/- SEM); GRF-stimulated, 435 +/- 32 ng/well; GRF-pretreated, control, 63 +/- 3 ng/well, GRF-pretreated, GRF-stimulated, 73 +/- 3.4 ng/well]. Despite the marked depletion of cellular GH stores and the greatly diminished rGRF-stimulated GH release in cells that had been preexposed to rGRF, both forskolin and (Bu)2cAMP were able to induce a 2-fold stimulation of GH release. Incubation of the rGRF-pretreated cells with fresh medium which lacked rGRF resulted in gradual recovery of the ability of rGRF to stimulate GH release without complete reconstitution of the intracellular GH stores. These results indicate that exposure of rat pituitary cells to rGRF results in 1) partial depletion of intracellular GH stores; 2) a diminished ability of a subsequent rGRF challenge to elicit GH secretion and intracellular cAMP accumulation, and 3) a sustained ability of forskolin and (Bu)2cAMP to stimulate GH release, indicating that rGRF desensitization occurs in vitro.

  View details for Web of Science ID A1985AEG2300017

  View details for PubMedID 3918850

• CORTICOTROPIN-RELEASING FACTOR DESENSITIZATION OF ADRENOCORTICOTROPIC HORMONE-RELEASE IS AUGMENTED BY ARGININE VASOPRESSIN JOURNAL OF NEUROSCIENCE Hoffman, A. R., Ceda, G., Reisine, T. D. 1985; 5 (1): 234-242

  Abstract

  The desensitization of corticotropin-releasing factor (CRF)-stimulated ACTH release from and intracellular cyclic AMP accumulation in anterior pituitary cells was investigated in primary cultures of rat pituitary cells and in a mouse tumor cell line (AtT 20/D16-16). CRF potently stimulated ACTH secretion and cyclic AMP accumulation in both preparations. When primary cultures were preincubated with 100 nM CRF, 50% desensitization of ACTH release occurred within 4 hr while similar desensitization of cyclic AMP accumulation occurred by 1 hr. This desensitization was manifested as a reduced maximal CRF response. Concentrations of CRF as low as 1 to 10 pM induced desensitization. Pretreatment did not affect ACTH content nor did it alter the ability of epinephrine or forskolin to stimulate ACTH release. Pretreatment of AtT 20 cells, which are a homogeneous population of corticotrophs, with 100 nM CRF reduced the subsequent ability of CRF, but not of isoproterenol or of forskolin, to stimulate ACTH release and cyclic AMP formation. Preincubation of AtT 20 cells with isoproterenol did not affect the cyclic AMP or ACTH release responses induced by CRF, but did desensitize beta-adrenergic receptors. Arginine vasopressin (AVP) was a weak ACTH-releasing factor, but AVP enhanced CRF-directed ACTH release from primary cultures. When these cells were preincubated with both CRF and AVP, CRF desensitization occurred with lower concentrations of CRF than when CRF desensitization was induced by preincubating the cells with CRF alone. The ED50 for CRF-induced desensitization was 700 +/- 150 pM when the cells were exposed to CRF alone, and 20 +/- 15 pM when 1 microM AVP was added during the preincubation.(ABSTRACT TRUNCATED AT 250 WORDS)

  View details for Web of Science ID A1985TZ84200027

  View details for PubMedID 2981299

• REGULATION OF GROWTH-HORMONE RELEASE FROM CULTURED HUMAN PITUITARY-ADENOMAS BY SOMATOMEDINS AND INSULIN JOURNAL OF CLINICAL ENDOCRINOLOGY & METABOLISM Ceda, G. P., Hoffman, A. R., Silverberg, G. D., Wilson, D. M., Rosenfeld, R. G. 1985; 60 (6): 1204-1209

  Abstract

  GH secretion is stimulated by hypothalamic GH-releasing factor (GHRH) and inhibited by somatostatin. Since GH induces the production of insulin-like growth factors (IGF) in liver and other tissues, it is of interest to learn whether IGF alters GH release through long loop feedback inhibition. Pituitary adenomas which had been removed from six acromegalic patients were processed for dispersed cell cultures and/or cell membrane preparations. Binding studies using 125I-labeled IGF-I, IGF-II, and insulin revealed specific hormone binding for each ligand to cell membranes derived from four somatotropinomas. A partially purified somatomedin preparation inhibited basal and/or GHRH-stimulated GH release from cultured pituitary cells derived from three of four adenomas; there was no effect of somatomedin in one tumor. In a single tumor, insulin also partially inhibited GHRH-stimulated GH release. Additionally, in one nonadenomatous pituitary removed from a patient with diabetes mellitus, insulin and somatomedin inhibited GHRH-stimulated GH release, and insulin inhibited basal GH secretion. These results indicate that specific cell membrane receptors for somatomedin peptides and insulin may be found on cell membranes from GH-secreting tumors, and that somatomedins and insulin can inhibit GH release in cultured human somatotropinoma cells. Thus, these data suggest that somatomedins may exert feedback inhibition of GH secretion in some patients with acromegaly.

  View details for Web of Science ID A1985AHM2400025

  View details for PubMedID 3889029

• SUPPRESSION OF TUMOR SECRETION OF GROWTH-HORMONE RELEASING-FACTOR (GRF 1-40) AND GASTRIN BY A SOMATOSTATIN ANALOG Wilson, D. M., Hoffman, A. R. SLACK INC. 1985: A31–A31

  View details for Web of Science ID A1985TY84700180

• ACROMEGALY AND ZOLLINGER-ELLISON SYNDROME SECONDARY TO AN ISLET CELL TUMOR - CHARACTERIZATION AND QUANTIFICATION OF PLASMA AND TUMOR HUMAN GROWTH HORMONE-RELEASING FACTOR JOURNAL OF CLINICAL ENDOCRINOLOGY & METABOLISM Wilson, D. M., Ceda, G. P., Bostwick, D. G., Webber, R. J., Minkoff, J. R., Pont, A., Hintz, R. L., Bensch, K. G., Kraemer, F. B., Rosenfeld, R. G., Hoffman, A. R. 1984; 59 (5): 1002-1005

  Abstract

  A young woman with acromegaly and Zollinger-Ellison syndrome associated with a GH-releasing factor (GRF)- and gastrin-secreting metastatic islet cell carcinoma was studied by means of specific antisera which recognize various regions of the GRF molecule. Using specific immunohistochemical techniques, the tumor cells were shown to contain GRF, gastrin, and gastrin-releasing peptide, but not GH. During a 4-h period, plasma GRF levels averaged 5.6 +/- 1.4 ng/ml (+/- SD), while GH levels averaged 148 +/- 71 ng/ml. GH secretion was pulsatile and increased after TRH administration. GRF RIAs may be useful in establishing the diagnosis of acromegaly secondary to the ectopic secretion of GRF.

  View details for Web of Science ID A1984TP17300031

  View details for PubMedID 6090497

• CHARACTERIZATION OF HIGH-AFFINITY RECEPTORS FOR INSULIN-LIKE GROWTH FACTOR-I AND FACTOR-II ON RAT ANTERIOR-PITUITARY CELLS ENDOCRINOLOGY Rosenfeld, R. G., Ceda, G., Wilson, D. M., DOLLAR, L. A., Hoffman, A. R. 1984; 114 (5): 1571-1575

  Abstract

  Primary cultures of rat anterior pituitary cells were assessed for the presence of specific receptors for insulin and for the somatomedin peptides, insulin-like growth factors I and II (IGF-I and IGF-II). Specific binding per 100,000 pituitary cells averaged 9.45 +/- 1.69% (mean +/- SD) for [125I]IGF-II, 0.83 +/- 0.06% for [125I]IGF-I, and only 0.11% for [125I]insulin, IGF-II was twice as potent as IGF-I in displacing [125I]IGF-II, while insulin was totally nonreactive, IGF-I was 5-fold more potent than IGF-II at displacing [125I]IGF-I and 1000-fold more potent than insulin. Scatchard analysis of [125I]IGF-II binding revealed a curvilinear plot, which could be resolved into a high affinity receptor with a Ka of 7.0 X 10(8) M-1 and 120,000 receptor sites/cell, and a low affinity receptor with a Ka of 1.1 X 10(8) M-1 and 720,000 receptor sites/cell. The existence of abundant high affinity somatomedin receptors (especially for IGF-II) on rat anterior pituitary cells is consistent with a potential role for these peptides in the regulation of GH secretion.

  View details for Web of Science ID A1984SP24200014

  View details for PubMedID 6325123

• DESENSITIZATION OF CORTICOTROPIN-RELEASING FACTOR RECEPTORS BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS Reisine, T., Hoffman, A. 1983; 111 (3): 919-925

  Abstract

  Pretreatment of rat anterior pituitary cells with corticotropin releasing factor (CRF) rapidly and markedly reduced the ability of CRF to restimulate cyclic AMP formation and adrenocorticotropic hormone (ACTH) release. The effect was dependent on the length of time of pretreatment as well as the concentration of CRF. Neither basal nor intracellular immunoreactive ACTH levels nor basal cyclic AMP content were affected. CRF's stimulatory action on cyclic AMP formation and ACTH release recovered within one hour following CRF pretreatment. Forskolin, a compound that directly activates adenylate cyclase also releases ACTH from these cells. Pretreatment with CRF did not alter forskolin-stimulated cyclic AMP accumulation or ACTH secretion. Furthermore, CRF pretreatment did not change epinephrine's ability to increase the release of ACTH. These results indicate that CRF can regulate the responsiveness of its own receptor.

  View details for Web of Science ID A1983QJ66100022

  View details for PubMedID 6301492

• DELAYED INCREASE OF ADRENAL TH AND PNMT ACTIVITIES FOLLOWING COLD STRESS IN MOUSE LIFE SCIENCES Hoffman, A., Harbaugh, R., Erdelyi, E., DORNBUSCH, J., CIARANELLO, R., BARCHAS, J. 1975; 17 (4): 557-562

  View details for Web of Science ID A1975AS68500010

  View details for PubMedID 241889