Academic Appointments

Honors & Awards

  • 2011 Vision Grant Award, presented at the Annual Gala 'Saving Grace - A Night of Hope and Gratitude', Preeclampsia Foundation (2011)
  • Building Interdisciplinary Research Careers in Women's Health (BIRCWH) Award, NIH (2004-2008)
  • Junior Investigator Award, Andrew W. Mellon Foundation (2000-2004)
  • Burroughs Wellcome Fund Travel Fellow, Society for the Study of Reproduction (1999)
  • Travel Grant Award, Endocrine Society (1999)
  • Postdoctoral Fellowship Award, Lalor Foundation (1998-2000)
  • AV Tilak Parvathi Devi Award, Association of Physiologists and Pharmacologists of India (1996)
  • Research Fellowship, Indian Council of Medical Research (1995-1997)
  • University Gold Medal for MVSc (Physiology), Orissa University of Agriculture and Technology (1989)
  • Junior Fellowship, Indian Council of Agricultural Research (1987-1989)

Professional Education

  • Postdoctoral Fellowship, ONPRC, Oregon, USA, Reproductive Sciences (2000)
  • PhD, AIIMS, New Delhi, Reproductive Physiology (1998)
  • MVSc, Orissa Univ of Agril and Tech, Veterinary Physiology (1989)
  • BVSc & AH, Orissa Univ of Agril and Tech, Veterinary Medicine (1986)

Research & Scholarship

Current Research and Scholarly Interests

Research in my laboratory is focused on understanding the mechanisms of endometrial angiogenesis and vascular remodeling during the menstrual cycle and pregnancy. We are particularly interested in understanding the mechanisms of spiral artery growth and remodeling in the primate uterus. These arteries are unique to the primate endometrium. They develop from the radial arteries of the myometrium and course through the endometrium, where they develop their coiled structure and vascularize primarily the upper endometrial zones. Their growth is primarily driven by progesterone in the luteal phase of the menstrual cycle and pregnancy. At the end of a nonfertile cycle, when progesterone levels fall, the spiral arteries severely constrict, leading to ischemia of the upper endometrial zones and menstrual breakdown of endometrium. During pregnancy, the trophoblasts invade the spiral arteries and replace the internal lining of these arteries, thereby regulate the vascular resistance and blood flow to the placenta and fetus. The degree of trophoblast invasion into these arteries appears to be a major determinant of pregnancy outcome. Inadequate invasion, particularly restricted endovascular invasion of spiral arteries, has been implicated in the pathophysiology of preeclampsia, preterm labor, and intrauterine growth restriction (lUGR). We believe that most of the pregnancy-related vascular complications manifested late in gestation, including preeclampsia, have their origins early in pregnancy. Our main goal is to identify the abnormalities in implantation that may lead to various pregnancy-related vascular complications.


2013-14 Courses

Postdoctoral Advisees


Journal Articles

  • Transient, Inducible, Placenta-Specific Gene Expression in Mice ENDOCRINOLOGY Fan, X., Petitt, M., Gamboa, M., Huang, M., Dhal, S., Druzin, M. L., Wu, J. C., Chen-Tsai, Y., Nayak, N. R. 2012; 153 (11): 5637-5644


    Molecular understanding of placental functions and pregnancy disorders is limited by the absence of methods for placenta-specific gene manipulation. Although persistent placenta-specific gene expression has been achieved by lentivirus-based gene delivery methods, developmentally and physiologically important placental genes have highly stage-specific functions, requiring controllable, transient expression systems for functional analysis. Here, we describe an inducible, placenta-specific gene expression system that enables high-level, transient transgene expression and monitoring of gene expression by live bioluminescence imaging in mouse placenta at different stages of pregnancy. We used the third generation tetracycline-responsive tranactivator protein Tet-On 3G, with 10- to 100-fold increased sensitivity to doxycycline (Dox) compared with previous versions, enabling unusually sensitive on-off control of gene expression in vivo. Transgenic mice expressing Tet-On 3G were created using a new integrase-based, site-specific approach, yielding high-level transgene expression driven by a ubiquitous promoter. Blastocysts from these mice were transduced with the Tet-On 3G-response element promoter-driving firefly luciferase using lentivirus-mediated placenta-specific gene delivery and transferred into wild-type pseudopregnant recipients for placenta-specific, Dox-inducible gene expression. Systemic Dox administration at various time points during pregnancy led to transient, placenta-specific firefly luciferase expression as early as d 5 of pregnancy in a Dox dose-dependent manner. This system enables, for the first time, reliable pregnancy stage-specific induction of gene expression in the placenta and live monitoring of gene expression during pregnancy. It will be widely applicable to studies of both placental development and pregnancy, and the site-specific Tet-On G3 mouse will be valuable for studies in a broad range of tissues.

    View details for DOI 10.1210/en.2012-1556

    View details for Web of Science ID 000310359300049

    View details for PubMedID 23011919

  • Decreased Circulating Soluble Tie2 Levels in Preeclampsia May Result from Inhibition of Vascular Endothelial Growth Factor (VEGF) Signaling JOURNAL OF CLINICAL ENDOCRINOLOGY & METABOLISM Sung, J. F., Fan, X., Dhal, S., Dwyer, B. K., Jafari, A., El-Sayed, Y. Y., Druzin, M. L., Nayak, N. R. 2011; 96 (7): E1148-E1152


    Recent studies have found dysregulation in circulating levels of a number of angiogenic factors and their soluble receptors in preeclampsia. In this study, we examined the mechanism of production of soluble Tie2 (sTie2) and its potential connection to the failure of vascular remodeling in preeclamptic pregnancies.Serum samples were collected prospectively from 41 pregnant subjects at five different time points throughout pregnancy. Five of these subjects developed preeclampsia. For a second study, serum and placental samples were collected at delivery from preeclamptic and gestational age-matched controls. We examined serum sTie2 levels, and angiopoietin 1, angiopoietin 2, and Tie2 mRNA expression and localization in placental samples from the central basal plate area. We also examined the effects of vascular endothelial growth factor (VEGF) and a matrix metalloproteinase (MMP) inhibitor on proteolytic shedding of Tie2 in uterine microvascular endothelial cells.Serum sTie2 levels were significantly lower in preeclamptic subjects starting at 24-28 wk of gestation and continued to be lower through the time of delivery. In culture experiments, VEGF treatment significantly increased sTie2 levels in conditioned media, whereas the MMP inhibitor completely blocked this increase, suggesting that VEGF-induced Tie2 release is MMP dependent.Our data suggest, for the first time, an interaction between VEGF and Tie2 in uterine endothelial cells and a potential mechanism for the decrease in circulating sTie2 levels in preeclampsia, likely through inhibition of VEGF signaling. Further studies on VEGF-Tie2 interactions during pregnancy should provide new insights into the mechanisms underlying the failure of vascular remodeling in preeclampsia and other pregnancy complications.

    View details for DOI 10.1210/jc.2011-0063

    View details for Web of Science ID 000292454500015

    View details for PubMedID 21525162

  • Noninvasive Monitoring of Placenta-Specific Transgene Expression by Bioluminescence Imaging PLOS ONE Fan, X., Ren, P., Dhal, S., Bejerano, G., Goodman, S. B., Druzin, M. L., Gambhir, S. S., Nayak, N. R. 2011; 6 (1)


    Placental dysfunction underlies numerous complications of pregnancy. A major obstacle to understanding the roles of potential mediators of placental pathology has been the absence of suitable methods for tissue-specific gene manipulation and sensitive assays for studying gene functions in the placentas of intact animals. We describe a sensitive and noninvasive method of repetitively tracking placenta-specific gene expression throughout pregnancy using lentivirus-mediated transduction of optical reporter genes in mouse blastocysts.Zona-free blastocysts were incubated with lentivirus expressing firefly luciferase (Fluc) and Tomato fluorescent fusion protein for trophectoderm-specific infection and transplanted into day 3 pseudopregnant recipients (GD3). Animals were examined for Fluc expression by live bioluminescence imaging (BLI) at different points during pregnancy, and the placentas were examined for tomato expression in different cell types on GD18. In another set of experiments, blastocysts with maximum photon fluxes in the range of 2.0E+4 to 6.0E+4 p/s/cm(2)/sr were transferred. Fluc expression was detectable in all surrogate dams by day 5 of pregnancy by live imaging, and the signal increased dramatically thereafter each day until GD12, reaching a peak at GD16 and maintaining that level through GD18. All of the placentas, but none of the fetuses, analyzed on GD18 by BLI showed different degrees of Fluc expression. However, only placentas of dams transferred with selected blastocysts showed uniform photon distribution with no significant variability of photon intensity among placentas of the same litter. Tomato expression in the placentas was limited to only trophoblast cell lineages.These results, for the first time, demonstrate the feasibility of selecting lentivirally-transduced blastocysts for uniform gene expression in all placentas of the same litter and early detection and quantitative analysis of gene expression throughout pregnancy by live BLI. This method may be useful for a wide range of applications involving trophoblast-specific gene manipulations in utero.

    View details for DOI 10.1371/journal.pone.0016348

    View details for Web of Science ID 000286522300037

    View details for PubMedID 21283713

  • VEGF blockade inhibits angiogenesis and reepithelialization of endometrium FASEB JOURNAL Fan, X., Krieg, S., Kuo, C. J., Wiegand, S. J., Rabinovitch, M., Druzin, M. L., Brenner, R. M., Giudice, L. C., Nayak, N. R. 2008; 22 (10): 3571-3580


    Despite extensive literature on vascular endothelial growth factor (VEGF) expression and regulation by steroid hormones, the lack of clear understanding of the mechanisms of angiogenesis in the endometrium is a major limitation for use of antiangiogenic therapy targeting endometrial vessels. In the current work, we used the rhesus macaque as a primate model and the decidualized mouse uterus as a murine model to examine angiogenesis during endometrial breakdown and regeneration. We found that blockade of VEGF action with VEGF Trap, a potent VEGF blocker, completely inhibited neovascularization during endometrial regeneration in both models but had no marked effect on preexisting or newly formed vessels, suggesting that VEGF is essential for neoangiogenesis but not survival of mature vessels in this vascular bed. Blockade of VEGF also blocked reepithelialization in both the postmenstrual endometrium and the mouse uterus after decidual breakdown, evidence that VEGF has pleiotropic effects in the endometrium. In vitro studies with a scratch wound assay showed that the migration of luminal epithelial cells during repair involved signaling through VEGF receptor 2-neuropilin 1 (VEGFR2-NP1) receptors on endometrial stromal cells. The leading front of tissue growth during endometrial repair was strongly hypoxic, and this hypoxia was the local stimulus for VEGF expression and angiogenesis in this tissue. In summary, we provide novel experimental data indicating that VEGF is essential for endometrial neoangiogenesis during postmenstrual/postpartum repair.

    View details for DOI 10.1096/fj.08-111401

    View details for Web of Science ID 000259642600019

    View details for PubMedID 18606863

  • Soluble receptor-mediated selective inhibition of VEGFR and PDGFR beta signaling during physiologic and tumor angiogenesis PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Kuhnert, F., Tam, B. Y., Sennino, B., Gray, J. T., Yuan, J., Jocson, A., Nayak, N. R., Mulligan, R. C., McDonald, D. M., Kuo, C. J. 2008; 105 (29): 10185-10190


    The simultaneous targeting of both endothelial cells and pericytes via inhibition of VEGF receptor (VEGFR) and PDGFbeta receptor (PDGFRbeta) signaling, respectively, has been proposed to enhance the efficacy of antiangiogenic tumor therapy. Clinical and preclinical modeling of combined VEGFR and PDGFRbeta signaling inhibition, however, has used small molecule kinase inhibitors with inherently broad substrate specificities, precluding detailed examination of this hypothesis. Here, adenoviral expression of a soluble VEGFR2/Flk1 ectodomain (Ad Flk1-Fc) in combination with a soluble ectodomain of PDGFRbeta (Ad sPDGFRbeta) allowed highly selective inhibition of these pathways. The activity of Ad sPDGFRbeta was validated in vitro against PDGF-BB and in vivo with near-complete blockade of pericyte recruitment in the angiogenic corpus luteum, resulting in prominent hemorrhage, thus demonstrating an essential function for PDGF signaling during ovarian angiogenesis. Combination therapy with Ad PDGFRbeta and submaximal doses of Ad Flk1-Fc produced modest additive antitumor effects; however, no additivity was observed with maximal VEGF inhibition in numerous s.c. models. Notably, VEGF inhibition via Ad Flk1-Fc was sufficient to strongly suppress tumor endothelial and pericyte content as well as intratumoral PDGF-B mRNA, obscuring additive Ad sPDGFRbeta effects on pericytes or tumor volume. These studies using highly specific soluble receptors suggest that additivity between VEGFR and PDGFRbeta inhibition depends on the strength of VEGF blockade and appears minimal under conditions of maximal VEGF antagonism.

    View details for DOI 10.1073/pnas.0803194105

    View details for Web of Science ID 000257913200061

    View details for PubMedID 18632559

  • VEGF modulates erythropoiesis through regulation of adult hepatic erythropoietin synthesis. Nature Medicine Tam BY, Wei K, Rudge JS, Hoffman J, Holash J, Park SK, Yuan J, Hefner C, Chartier C, Lee JS, Jiang S, Nayak NR, Kuypers FA, Ma L, Sundram U, Wu G, Garcia JA, Schrier SL, Maher JJ, Johnson RS, Yancopoulos GD, Mulligan RC, Kuo CJ 2006; 12 (7): 793-800
  • Maternal Fish Consumption and Prevention of Low Birth Weight in the Developing World NATIONAL ACADEMY SCIENCE LETTERS-INDIA Mohanty, B. P., Ganguly, S., Karunakaran, D., Chakraborty, K., Sharma, A. P., Mohapatra, P. K., Nayak, N. R. 2012; 35 (5): 433-438
  • Global alteration in gene expression profiles of deciduas from women with idiopathic recurrent pregnancy loss MOLECULAR HUMAN REPRODUCTION Krieg, S. A., Fan, X., Hong, Y., Sang, Q., Giaccia, A., Westphal, L. M., Lathi, R. B., Krieg, A. J., Nayak, N. R. 2012; 18 (9): 442-450


    Recurrent pregnancy loss (RPL) occurs in ?5% of women. However, the etiology is still poorly understood. Defects in decidualization of the endometrium during early pregnancy contribute to several pregnancy complications, such as pre-eclampsia and intrauterine growth restriction (IUGR), and are believed to be important in the pathogenesis of idiopathic RPL. We performed microarray analysis to identify gene expression alterations in the deciduas of idiopathic RPL patients. Control patients had one antecedent term delivery, but were undergoing dilation and curettage for current aneuploid miscarriage. Gene expression differences were evaluated using both pathway and gene ontology (GO) analysis. Selected genes were validated using quantitative reverse transcription-polymerase chain reaction (qRT-PCR). A total of 155 genes were found to be significantly dysregulated in the deciduas of RPL patients (>2-fold change, P < 0.05), with 22 genes up-regulated and 133 genes down-regulated. GO analysis linked a large percentage of genes to discrete biological functions, including immune response (23%), cell signaling (18%) and cell invasion (17.1%), and pathway analysis revealed consistent changes in both the interleukin 1 (IL-1) and IL-8 pathways. All genes in the IL-8 pathway were up-regulated while genes in the IL-1 pathway were down-regulated. Although both pathways can promote inflammation, IL-1 pathway activity is important for normal implantation. Additionally, genes known to be critical for degradation of the extracellular matrix, including matrix metalloproteinase 26 and serine peptidase inhibitor Kazal-type 1, were also highly up-regulated. In this first microarray approach to decidual gene expression in RPL patients, our data suggest that dysregulation of genes associated with cell invasion and immunity may contribute significantly to idiopathic recurrent miscarriage.

    View details for DOI 10.1093/molehr/gas017

    View details for Web of Science ID 000308243000003

    View details for PubMedID 22505054

  • Dynamic Regulation of Wnt7a Expression in the Primate Endometrium: Implications for Postmenstrual Regeneration and Secretory Transformation ENDOCRINOLOGY Fan, X., Krieg, S., Hwang, J. Y., Dhal, S., Kuo, C. J., Lasley, B. L., Brenner, R. M., Nayak, N. R. 2012; 153 (3): 1063-1069


    Despite the vital physiological role of endometrial regeneration during the menstrual cycle and the various pathological implications of abnormal growth of endometrial epithelial cells, the local factors and regulatory mechanisms involved in endometrial regeneration and growth have not been well characterized. Here, we examine the pattern, hormone dependence, and potential functions of Wnt7a (wingless-type MMTV integration site family member 7a), which is known to play a critical role in the formation of the mouse endometrial epithelium during embryonic development, in both human and artificially cycling rhesus macaque endometrium, and using a potent Wnt-antagonist in a mouse model of endometrial regeneration. Wnt7a transcript levels were examined using quantitative real-time PCR and in situ hybridization, and immunohistochemistry was performed to detect Ki-67 and 3,5-bromodeoxyuridine. Stringent, fully conditional Wnt inhibition was achieved by adenoviral expression of Dickkopf-1 during artificial endometrial regeneration in mice. In macaques, Wnt7a expression was confined to the newly formed luminal epithelium (LE) and upper glands during the postmenstrual repair phase. The signal increased in the LE during the proliferative phase but decreased in the upper glands and was undetectable in the glands by the late proliferative phase. Interestingly, Wnt7a was completely suppressed in the LE and remained undetectable in other cell types after 7 d of progesterone treatment. The pattern of Wnt7a expression in the human endometrium was similar to that in macaques. Blockade of Wnt signaling during endometrial regeneration in mice resulted in a dramatic delay in reepithelialization and degeneration of glands and LE. These results strongly suggest, for the first time, a role for Wnt7a in postmenstrual regeneration and proliferation of endometrial glands and LE in primates, and its dramatic suppression by progesterone is likely essential for secretory transformation of the epithelium.

    View details for DOI 10.1210/en.2011-1826

    View details for Web of Science ID 000300645600013

    View details for PubMedID 22294752

  • Variable expression of soluble fms-like tyrosine kinase 1 in patients at high risk for preeclampsia JOURNAL OF MATERNAL-FETAL & NEONATAL MEDICINE Dwyer, B. K., Krieg, S., Balise, R., Carroll, I. R., Chueh, J., Nayak, N., Druzin, M. 2010; 23 (7): 705-711


    To explore angiogenic factor differences in preeclamptic patients according to the absence or presence of underlying vascular disease.We prospectively compared serum soluble fms-like tyrosine kinase 1 (sFlt1), soluble endoglin, and placental growth factor (PlGF) from 41 normal-risk and 32 high-risk (preexisting conditions) subjects at serial gestational ages.Median sFlt1 was lower at delivery in preeclamptic patients with underlying chronic hypertension and/or chronic proteinuria (5115 pg/ml) compared with normal risk preeclamptic patients (16375 pg/ml). PlGF was consistently low in patients who developed preeclampsia.Effects of sFlt1 may be contextual, varying according to the health or disease state of vascular endothelium.

    View details for DOI 10.3109/14767050903258753

    View details for Web of Science ID 000279865300024

    View details for PubMedID 19895348

  • Lack of Functional Pregnancy-Associated Plasma Protein-A (PAPPA) Compromises Mouse Ovarian Steroidogenesis and Female Fertility BIOLOGY OF REPRODUCTION Nyegaard, M., Overgaard, M. T., Su, Y., Hamilton, A. E., Kwintkiewicz, J., Hsieh, M., Nayak, N. R., Conti, M., Conover, C. A., Giudice, L. C. 2010; 82 (6): 1129-1138


    The insulin-like growth factor (IGF) system plays an important role in regulating ovarian follicular development and steroidogenesis. IGF binding proteins (IGFBP) mostly inhibit IGF actions, and IGFBP proteolysis is a major mechanism for regulating IGF bioavailability. Pregnancy-associated plasma protein-A (PAPPA) is a secreted metalloprotease responsible for cleavage of IGFBP4 in the ovary. The aim of this study was to investigate whether PAPPA plays a role in regulating ovarian functions and female fertility by comparing the reproductive phenotype of wild-type (WT) mice with mice heterozygous or homozygous for a targeted Pappa gene deletion (heterozygous and PAPP-A knockout [KO] mice, respectively). When mated with WT males, PAPP-A KO females demonstrated an overall reduction in average litter size. PAPP-A KO mice had a reduced number of ovulated oocytes, lower serum estradiol levels following equine chorionic gonadotropin administration, lower serum progesterone levels after human chorionic gonadotropin injection, and reduced expression of ovarian steroidogenic enzyme genes, compared to WT controls. In PAPP-A KO mice, inhibitory IGFBP2, IGFBP3, and IGFBP4 ovarian gene expression was reduced postgonadotropin stimulation, suggesting some compensation within the ovarian IGF system. Expression levels of follicle-stimulating hormone receptor, luteinizing hormone receptor, and genes required for cumulus expansion were not affected. Analysis of preovulatory follicular fluid showed complete loss of IGFBP4 proteolytic activity in PAPP-A KO mice, demonstrating no compensation for loss of PAPPA proteolytic activity by other IGFBP proteases in vivo in the mouse ovary. Taken together, these data demonstrate an important role of PAPPA in modulating ovarian function and female fertility by control of the bioavailability of ovarian IGF.

    View details for DOI 10.1095/biolreprod.109.079517

    View details for Web of Science ID 000277964500013

    View details for PubMedID 20130263

  • Multiple Cytokine Profile in Plasma and Amniotic Fluid in a Mouse Model of Pre-Term Labor AMERICAN JOURNAL OF REPRODUCTIVE IMMUNOLOGY Yang, Q., El-Sayed, Y., Rosenberg-Hasson, Y., Hirschberg, D. L., Nayak, N. R., Schilling, J., Madan, A. 2009; 62 (5): 339-347


    The rate of pre-term birth in the United States continues to rise despite several interventions. Induction of pro-inflammatory cytokines and chemokines has been implicated in the activation of the cascade of events resulting in pre-term labor. To date, no comprehensive panel of the cytokine profile in PTL has been published.To address cytokine profiles in pre-term labor, levels of 19 plasma and amniotic fluid cytokines were measured using a multiplex immunoassay in an inflammation-induced murine model of pre-term labor.Pro-inflammatory mediators, RANTES, KC, IL-6, and IL-12p40 were increased by 3 hr and remained high at 15 hr. Concentrations of KC, IL-6, IL-1beta, and MIP-1alpha were increased in the amniotic fluid at 15 hr. Plasma levels of anti-inflammatory mediators IL-10 and IL-13 at 15 hr were unchanged and decreased respectively.These results suggest that stimulation of several pro-inflammatory cytokines occurs very early in the cascade of events and remains increased, whereas anti-inflammatory cytokines are either unchanged or decreased until the onset of delivery in an inflammation-induced mouse model of pre-term labor.

    View details for DOI 10.1111/j.1600-0897.2009.00743.x

    View details for Web of Science ID 000270610900009

    View details for PubMedID 19811468

  • Effect of Heme Oxygenase-1 Deficiency on Placental Development PLACENTA Zhao, H., Wong, R. J., Kalish, F. S., Nayak, N. R., Stevenson, D. K. 2009; 30 (10): 861-868


    Heme oxygenase (HO) is the rate-limiting enzyme in the heme catabolic pathway and highly expressed in the placenta. Deficiencies in HO-1, the inducible isoform, have been associated with pregnancy disorders, such as recurrent miscarriages, intrauterine growth retardation, and pre-eclampsia. The aim of this study was to identify if a deficiency in HO-1 affects placental development using a mouse model. When HO-1 heterozygote (Het, HO-1(+/-)) mice were cross-bred, an extremely low birth rate in homozygote (Mut, HO-1(-/-)) offspring (2.4%) and small litter sizes were observed. Placentas and fetuses from Het cross-breedings were relatively smaller and weighed less than those from wild-type (WT) cross-breedings at E12.5 and E15.5. Furthermore, Het placentas had significantly less HO-1 mRNA and protein levels than WT placentas, but no significant differences in placental HO activity. Interestingly, HO-2, the constituitive HO isoform, as well as iNOS and eNOS expression were significantly upregulated in Het placentas. Histological examination showed that the junctional zone (JZ) of Het placentas were markedly thinner than those of WT placentas and appeared to be due to an increase in apoptosis. Immunohistochemistry revealed that HO-1-expressing cells were located primarily in the JZ of Het placentas, specifically in the spongiotrophoblast layer. In addition, diastolic blood pressures and plasma soluble VEGFR-1 (sFlt-1) levels were significantly elevated in pregnant Het mice. We conclude that a partial deficiency in HO-1 is associated with morphological changes in the placenta and elevations in maternal diastolic blood pressure and plasma sFlt-1 levels, despite a compensatory increase in HO-2 expression.

    View details for DOI 10.1016/j.placenta.2009.07.012

    View details for Web of Science ID 000270706300006

    View details for PubMedID 19699520

  • Plasma Biomarkers in a Mouse Model of Preterm Labor PEDIATRIC RESEARCH Yang, Q., Whitin, J. C., Ling, X. B., Nayak, N. R., Cohen, H. J., Jin, J., Schilling, J., Yu, T. T., Madan, A. 2009; 66 (1): 11-16


    Preterm labor (PTL) is frequently associated with inflammation. We hypothesized that biomarkers during pregnancy can identify pregnancies most at risk for development of PTL. An inflammation-induced mouse model of PTL was used. Surface-enhanced laser desorption/ionization time-of-flight mass spectrometry was used to analyze and compare the plasma protein (PP) profile between CD-1 mice injected intrauterine with either lipopolysaccharide (LPS) or PBS on d 14.5 of gestation. The median differences of normalized PP peaks between the two groups were determined using the Mann-Whitney U test and the false discovery rate. In a second series of experiments, both groups of mice were injected with a lower dose of LPS. A total of 1665 peaks were detected. Thirty peaks were highly differentially expressed (p < 0.0001) between the groups. Two 11 kDa protein peaks were identified by MALDI-TOF/TOF-MS and confirmed to be mouse serum amyloid A (SAA) 1 and 2. Plasma SAA2 levels were increased in LPS-treated animals compared with controls and in LPS-treated animals that delivered preterm vs. those that delivered at term. SAA2 has the potential to be a plasma biomarker that can identify pregnancies at risk for development of PTL.

    View details for Web of Science ID 000267249300004

    View details for PubMedID 19287348

  • Regulation of Angiogenesis in the Primate Endometrium: Vascular Endothelial Growth Factor SEMINARS IN REPRODUCTIVE MEDICINE Chennazhi, K. P., Nayak, N. R. 2009; 27 (1): 80-89


    Unlike other tissues, endometrial vessels are unique because their functions are primarily orchestrated under the influence of ovarian steroid hormones, estradiol and progesterone. Although there is controversy in the literature on the expression of steroid hormone receptors in endometrial endothelial and vascular smooth muscle cells, it is believed that the actions of estradiol and progesterone are primarily mediated by paracrine interactions between the vascular and other cells of the endometrium. However, the regulatory mechanisms and local factors involved in mediating these paracrine interactions are not fully understood. Numerous angiogenic factors have been identified and implicated in endometrial vascular development and differentiation, but their relative contribution in endometrial angiogenesis is unknown. This review primarily focuses on the current progress in understanding the roles of a prototypical angiogenic factor, the vascular endothelial growth factor (VEGF), in the primate endometrium. Regulation of VEGF and its receptors in the endometrium appears to be highly complex, regulated by both steroid hormones as well as local factors independent of steroid hormones. The zone-specific and the cell-type specific expression of VEGF and its receptors in the endometrium suggest that steroid hormones likely regulate their expression through local cell-specific regulatory factors, rather than through direct gene transcription. Because VEGF receptors are expressed in both endothelial and nonendothelial cells, VEGF may have a pleiotropic role in this tissue. Recent development of highly potent VEGF inhibitors provides an opportunity to study the roles of VEGF in the primate endometrium. It is imperative that future studies focus on understanding specific roles of VEGF using these inhibitors, which is critically needed for development of new therapeutic strategies for numerous endometrial vascular disorders.

    View details for DOI 10.1055/s-0028-1108012

    View details for Web of Science ID 000262260400009

    View details for PubMedID 19197807

  • Regulation of maternal and fetal hemodynamics by heme oxygenase in mice BIOLOGY OF REPRODUCTION Zhao, H., Wong, R. J., Doyle, T. C., Nayak, N., Vreman, H. J., Contag, C. H., Stevenson, D. K. 2008; 78 (4): 744-751


    Heme oxygenase (HMOX) regulates vascular tone and blood pressure through the production of carbon monoxide (CO), a vasodilator derived from the heme degradation pathway. During pregnancy, the maternal circulation undergoes significant adaptations to accommodate the hemodynamic demands of the developing fetus. Our objective was to investigate the role of HMOX on maternal and fetal hemodynamics during pregnancy in a mouse model. We measured and compared maternal tissue and placental HMOX activity and endogenous CO production, represented by excreted CO and carboxyhemoglobin levels, during pregnancy (Embryonic Days 12.5-15.5) to nonpregnant controls. Micro-ultrasound was used to monitor maternal abdominal aorta diameters as well as blood flow velocities and diameters of fetal umbilical arteries. Tin mesoporphyrin, a potent HMOX inhibitor, was used to inhibit HMOX activity. Changes in maternal vascular tone were monitored by tail cuff blood pressure measurements. Effects of HMOX inhibition on placental structures were assessed by histology. We showed that maternal tissue and placental HMOX activity and CO production were significantly elevated during pregnancy. When HMOX in the placenta was inhibited, maternal and fetal hemodynamics underwent significant changes, with maternal blood pressures increasing. We concluded that increases in maternal tissue and placental HMOX activity contribute to the regulation of peripheral vascular resistance and therefore are important for the maintenance of normal maternal vascular tone and fetal hemodynamic functions during pregnancy.

    View details for DOI 10.1095/biolreprod.107.064899

    View details for Web of Science ID 000254217500020

    View details for PubMedID 18094356

  • Antiprogestin-releasing intrauterine devices: a novel approach to endometrial contraception CONTRACEPTION Nayak, N. R., Slayden, O. D., Mah, K., Chwalisz, K., Brenner, R. M. 2007; 75 (6): S104-S111


    Intrauterine devices (IUDs) that release progestins are highly effective contraceptives, but they induce breakthrough bleeding that some women find unacceptable. Because progesterone (P) antagonists [antiprogestins (APs)] are known to suppress the endometrium, induce amenorrhea and inhibit fertility, AP-releasing IUDs (AP-IUDs) may provide an effective contraceptive that also controls endometrial bleeding. Here, we assessed the effects of empty (blank) vs. AP-IUDs (ZK 230 211) on bleeding patterns and endometrial growth in ovariectomized, artificially cycled macaques. The AP-IUDs (but not the blank controls) induced extended, frank menstruation when inserted during the late luteal phase, an indication of local AP action. Over time, endometrial glandular and arterial proliferation were inhibited, steroid receptors were elevated, spiral arteries showed degenerative changes, P withdrawal bleeding was prevented, and estradiol (E(2))-dependent proliferation was suppressed by the AP-IUDs. In sum, AP-IUDs suppressed the effects of P on endometrial progestational development and blocked the effects of E(2) on endometrial proliferation, as previously shown for systemic treatment with APs. Therefore, AP IUDs may provide novel contraceptive devices with minimal breakthrough bleeding.

    View details for DOI 10.1016/j.contraception.2007.01.024

    View details for Web of Science ID 000247189200018

    View details for PubMedID 17531599

  • Decidual stromal cell response to paracrine signals from the trophoblast: Amplification of immune and angiogenic modulators BIOLOGY OF REPRODUCTION Hess, A. P., Hamilton, A. E., Talbi, S., Dosiou, C., Nyegaard, M., Nayak, N., Genbecev-Krtolica, O., Mavrogianis, P., Ferrer, K., Kruessel, J., Fazleabas, A. T., Fisher, S. J., Giudice, L. C. 2007; 76 (1): 102-117


    During the invasive phase of implantation, trophoblasts and maternal decidual stromal cells secrete products that regulate trophoblast differentiation and migration into the maternal endometrium. Paracrine interactions between the extravillous trophoblast and the maternal decidua are important for successful embryonic implantation, including establishing the placental vasculature, anchoring the placenta to the uterine wall, and promoting the immunoacceptance of the fetal allograph. To our knowledge, global crosstalk between the trophoblast and the decidua has not been elucidated to date, and the present study used a functional genomics approach to investigate these paracrine interactions. Human endometrial stromal cells were decidualized with progesterone and further treated with conditioned media from human trophoblasts (TCM) or, as a control, with control conditioned media (CCM) from nondecidualized stromal cells for 0, 3, and 12 h. Total RNA was isolated and processed for analysis on whole-genome, high-density oligonucleotide arrays containing 54,600 genes. We found that 1374 genes were significantly upregulated and that 3443 genes were significantly downregulated after 12 h of coincubation of stromal cells with TCM, compared to CCM. Among the most upregulated genes were the chemokines CXCL1 (GRO1) and IL8,CXCR4, and other genes involved in the immune response (CCL8 [SCYA8], pentraxin 3 (PTX3), IL6, and interferon-regulated and -related genes) as well as TNFAIP6 (tumor necrosis factor alpha-induced protein 6) and metalloproteinases (MMP1, MMP10, and MMP14). Among the downregulated genes were growth factors, e.g., IGF1, FGF1, TGFB1, and angiopoietin-1, and genes involved in Wnt signaling (WNT4 and FZD). Real-time RT-PCR and ELISAs, as well as immunohistochemical analysis of human placental bed specimens, confirmed these data for representative genes of both up- and downregulated groups. The data demonstrate a significant induction of proinflammatory cytokines and chemokines, as well as angiogenic/static factors in decidualized endometrial stromal cells in response to trophoblast-secreted products. The data suggest that the trophoblast acts to alter the local immune environment of the decidua to facilitate the process of implantation and ensure an enriched cytokine/chemokine environment while limiting the mitotic activity of the stromal cells during the invasive phase of implantation.

    View details for DOI 10.1095/biolreprod.106.054791

    View details for Web of Science ID 000243057200013

    View details for PubMedID 17021345

  • Molecular phenotyping of human endometrium distinguishes menstrual cycle phases and underlying biological processes in normo-ovulatory women ENDOCRINOLOGY Talbi, S., Hamilton, A. E., Vo, K. C., Tulac, S., Overgaard, M. T., Dosiou, C., Le Shay, N., Nezhat, C. N., Kempson, R., Lessey, B. A., Nayak, N. R., Giudice, L. C. 2006; 147 (3): 1097-1121


    Histological evaluation of endometrium has been the gold standard for clinical diagnosis and management of women with endometrial disorders. However, several recent studies have questioned the accuracy and utility of such evaluation, mainly because of significant intra- and interobserver variations in histological interpretation. To examine the possibility that biochemical or molecular signatures of endometrium may prove to be more useful, we have investigated whole-genome molecular phenotyping (54,600 genes and expressed sequence tags) of this tissue sampled across the cycle in 28 normo-ovulatory women, using high-density oligonucleotide microarrays. Unsupervised principal component analysis of all samples revealed that samples self-cluster into four groups consistent with histological phenotypes of proliferative (PE), early-secretory (ESE), mid-secretory (MSE), and late-secretory (LSE) endometrium. Independent hierarchical clustering analysis revealed equivalent results, with two major dendrogram branches corresponding to PE/ESE and MSE/LSE and sub-branching into the four respective phases with heterogeneity among samples within each sub-branch. K-means clustering of genes revealed four major patterns of gene expression (high in PE, high in ESE, high in MSE, and high in LSE), and gene ontology analysis of these clusters demonstrated cycle-phase-specific biological processes and molecular functions. Six samples with ambiguous histology were identically assignable to a cycle phase by both principal component analysis and hierarchical clustering. Additionally, pairwise comparisons of relative gene expression across the cycle revealed genes/families that clearly distinguish the transitions of PE-->ESE, ESE-->MSE, and MSE-->LSE, including receptomes and signaling pathways. Select genes were validated by quantitative RT-PCR. Overall, the results demonstrate that endometrial samples obtained by two different sampling techniques (biopsy and curetting hysterectomy specimens) from subjects who are as normal as possible in a human study and including those with unknown histology, can be classified by their molecular signatures and correspond to known phases of the menstrual cycle with identical results using two independent analytical methods. Also, the results enable global identification of biological processes and molecular mechanisms that occur dynamically in the endometrium in the changing steroid hormone milieu across the menstrual cycle in normo-ovulatory women. The results underscore the potential of gene expression profiling for developing molecular diagnostics of endometrial normalcy and abnormalities and identifying molecular targets for therapeutic purposes in endometrial disorders.

    View details for DOI 10.1210/en.2005-1075

    View details for Web of Science ID 000235350100008

    View details for PubMedID 16306079

  • Expression, localization and hormonal control of angiopoietin-1 in the rhesus macaque endometrium: potential role in spiral artery growth MOLECULAR HUMAN REPRODUCTION Nayak, N. R., Kuo, C. J., Desai, T. A., Wiegand, S. J., Lasley, B. L., Giudice, L. C., Brenner, R. M. 2005; 11 (11): 791-799


    Angiopoietin-1 (Ang-1) is an important angiogenic factor that has not been thoroughly studied in the primate endometrium. We evaluated the endometrial expression of Ang-1 and its receptor, Tie2, during induced menstrual cycles in rhesus macaques. Tie2 expression was confined to the vascular endothelium without marked change during the cycle. However, Ang-1 expression varied considerably during the cycle. In the proliferative phase, Ang-1 was only expressed in the basal zone glands, and this expression was estradiol (E2) dependent. In the early- to mid-secretory phase, Ang-1 expression spread to the upper glands, luminal epithelium and the vascular smooth muscle cells (VSMC) of spiral arteries. In the late secretory phase, the signal disappeared from the glands but remained elevated in the VSMC of spiral arteries. Notably, there was a significant correlation between VSMC proliferation and Ang-1 expression in the VSMC of the spiral arteries. Progesterone (P) withdrawal in the early secretory phase induced a decline in Ang-1 expression in the glands and VSMC of spiral arteries along with a complete suppression of VSMC proliferation. These data suggest, for the first time, that Ang-1 may play a key role in the P-dependent growth of the unique spiral arteries in the primate endometrium.

    View details for DOI 10.1093/molehr/gah237

    View details for Web of Science ID 000235278700003

    View details for PubMedID 16390855

  • Dose-dependent insulin regulation of insulin-like growth factor binding protein-1 in human endometrial stromal cells is mediated by distinct signaling pathways JOURNAL OF CLINICAL ENDOCRINOLOGY & METABOLISM Lathi, R. B., Hess, A. P., Tulac, S., Nayak, N. R., Conti, M., Giudice, L. C. 2005; 90 (3): 1599-1606


    IGF binding protein-1 (IGFBP-1) is a major product of decidualized human endometrial stromal cells and decidua, and as a modulator of IGF action and/or by independent mechanisms, it regulates cell growth and differentiation and embryonic implantation in these tissues. IGFBP-1 secretion is primarily stimulated by progesterone and cAMP and is inhibited by insulin and IGFs. The signaling pathways mediating the latter are not well defined, and the current study was conducted to determine which pathways mediate the effects of insulin on IGFBP-1 mRNA and protein expression by human endometrial stromal cells decidualized in vitro by progesterone. Cells were cultured and treated with different combinations of insulin; wortmannin, an inhibitor of the phosphatidylinositide-3-kinase (PI3-kinase) pathway; and PD98059, an inhibitor of the MAPK pathway. IGFBP-1 mRNA was determined by real-time PCR, and protein secretion in the conditioned medium was measured by ELISA. Activation of the PI3-kinase and the MAPK pathways was assessed by the detection of phosphorylated AKT and ERK in Western blots, respectively. Insulin inhibited IGFBP-1 mRNA and protein secretion in a dose-dependent fashion, with an ED(50) for the latter 0.127 ng/ml (21.6 pm). Inhibitor studies revealed that at low doses, insulin acts through the PI3-kinase pathway, whereas at higher levels it also activates the MAPK pathway in the inhibition of IGFBP-1. The data demonstrate that human endometrium is a target for insulin action in the regulation of IGFBP-1. At physiological levels insulin likely plays a homeostatic role for energy metabolism in the endometrium, and in hyperinsulinemic states, insulin action on the endometrium may activate cellular mitosis via the MAPK pathway and perhaps predispose this tissue to hyperplasia and/or cancer.

    View details for DOI 10.1210/jc.2004-1676

    View details for Web of Science ID 000227523600050

    View details for PubMedID 15613433

  • Cellular expression and hormonal regulation of neuropilin-1 and-2 messenger ribonucleic acid in the human and rhesus macaque endometrium JOURNAL OF CLINICAL ENDOCRINOLOGY & METABOLISM Germeyer, A., Hamilton, A. E., Laughlin, L. S., Lasley, B. L., Brenner, R. M., Giudice, L. C., Nayak, N. R. 2005; 90 (3): 1783-1790


    Although much is known about the biology of vascular endothelial growth factor (VEGF) and its cognate receptors (VEGFRs), VEGFR1 and VEGFR2, little is known about the roles of the VEGFRs neuropilin (NP)-1 and NP-2 in the primate endometrium. In this study, we investigated the cellular localization and hormonal regulation of NP-1 and NP-2 mRNA by in situ hybridization in the endometrium of ovariectomized, hormonally cycled rhesus macaques and women during the natural menstrual cycle. NP-1 mRNA was highly expressed in vascular endothelium and in stromal cells, but in these cells, NP-1 expression did not change during the menstrual cycle. However, NP-1 mRNA was also expressed in the luminal epithelium (not the glands), and its expression in these cells was elevated during the mid- to late proliferative phase and completely suppressed during the secretory phase. The increase in NP-1 level in the luminal epithelium was estradiol dependent because such expression was not detectable in the absence of estradiol in ovariectomized, hormone-deprived animals. Moreover, NP-1 expression in the luminal epithelium was highly correlated with the degree of proliferation in these cells. A recent study showed that blockade of VEGF action can inhibit luminal epithelial cell proliferation, but there is no evidence of VEGFR1 and VEGFR2 expression in these cells. Therefore, NP-1 may be the relevant VEGFR that mediates proliferation in this epithelium. NP-2 mRNA, unlike NP-1, was expressed only by the endothelium of veins, and in these cells, its expression was hormonally regulated in the converse manner: it was very low during the proliferative phase and high during the secretory phase. The increased permeability and edema observed during the secretory phase in the primate endometrium may be mediated in part by VEGF-NP-2 interaction. In the human endometrium, the pattern of expression and cellular localization of both NP-1 and NP-2 during the menstrual cycle were essentially identical with that seen in the rhesus macaque endometrium. These are the first data to specify the hormonal regulation and cell-specific expression of NP-1 and NP-2 mRNA in the endometrium of both women and nonhuman primates. The findings extend our understanding of VEGF action in the primate endometrium.

    View details for DOI 10.1210/jc.2004-1769

    View details for Web of Science ID 000227523600077

    View details for PubMedID 15613413

  • The immune environment in human endometrium during the window of implantation AMERICAN JOURNAL OF REPRODUCTIVE IMMUNOLOGY Lobo, S. C., Huang, S. T., Germeyer, A., Dosiou, C., Vo, K. C., Tulac, S., Nayak, N. R., Giudice, L. C. 2004; 52 (4): 244-251


    Changes in the immune environment in the endometrium are believed to be important for successful implantation and maintenance of pregnancy. We have previously investigated global gene profiling in human endometrium during the window of implantation by oligonucleotide microarray technology, and analysis of these data underscore the regulation of a group of immune-related genes. The present study was therefore conducted to examine the pattern of expression and regulation of these genes including decay accelerating factor (DAF), indoleamine 2,3 dioxygenase (IDO), interleukin-15 (IL-15), IL-15 receptor alpha subunit (IL-15Ralpha), interferon regulatory factor-1 (IRF-1), lymphotactin (Lpn), natural killer-associated transcript 2 (NKAT2) and NKG5 in secretory and proliferative human endometrium.Endometrial biopsies were obtained from normally cycling women in the late proliferative and mid-secretory phase of the menstrual cycle. Semi-quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) and Northern blot analysis were used to determine the expression and regulation of these genes in secretory and proliferative human endometrium. Cellular localization of NKG5, Lpn and IDO by in situ hybridization in secretory-phase endometrium was also examined.Semi-quantitative RT-PCR and Northern blot results demonstrate that there is a coordinated upregulation of this group of genes during the window of implantation.We demonstrate the upregulation of immune-related genes IL-15Ralpha, Lpn and NKG5 in secretory versus proliferative human endometrium. We also demonstrate a similar upregulation in secretory endometrium of other immune-related genes, viz, DAF, IDO, IL-15, IRF-1 and NKAT2. The functions of these genes include stimulation of proliferation of uterine natural killer (uNK) cells, inhibition of cytolytic activity of uNK cells, inhibition of cell growth of T cells and other pathogens and inhibition of the classical complement pathway. Upregulation of these immune-related genes in the window of implantation suggests their role during the process of implantation and in immune tolerance of the implanting conceptus.

    View details for Web of Science ID 000224562200003

    View details for PubMedID 15494045

  • A role for the androgen receptor in the endometrial antiproliferative effects of progesterone antagonists STEROIDS Brenner, R. M., Slayden, O. D., Nayak, N. R., Baird, D. T., Critchley, H. O. 2003; 68 (10-13): 1033-1039


    In women and nonhuman primates, treatment with progesterone antagonists suppresses estrogen-dependent mitotic activity in the endometrial glands. This antiproliferative effect is paradoxical, because progesterone antagonists do not bind to the estrogen receptor (ER). While this phenomenon has been termed a "functional noncompetitive antiestrogenic effect," it does not occur in all species or in all regions of the primate reproductive tract, so is best referred to as an "endometrial antiproliferative effect." Recent studies of ours in both women and macaques revealed that the endometrial androgen receptor (AR) was increased by progesterone antagonist treatment. Because androgens are known to suppress estrogen-dependent endometrial proliferation, we hypothesized that the AR was involved in the antiproliferative effects induced by progesterone antagonists. In a test of this hypothesis, we administered the antiandrogen, flutamide, along with progesterone antagonists to ovariectomized, estrogen-treated macaques. Flutamide counteracted the suppressive effects of the progesterone antagonists on endometrial wet weight, thickness, stromal compaction, and mitotic index. Hyaline degeneration of the spiral arteries was also blocked by flutamide. These data implicate the AR as a functional component of the mechanism through which progesterone antagonists induce endometrial antiproliferative effects in the presence of estrogens.

    View details for DOI 10.1016/S0039-128X(03)00120-X

    View details for Web of Science ID 000187565700032

    View details for PubMedID 14667996

  • Identification, characterization, and regulation of the canonical Wnt signaling pathway in human endometrium JOURNAL OF CLINICAL ENDOCRINOLOGY & METABOLISM Tulac, S., Nayak, N. R., Kao, L. C., van Waes, M., Huang, J., Lobo, S., Germeyer, A., Lessey, B. A., Taylor, R. N., Suchanek, E., Giudice, L. C. 2003; 88 (8): 3860-3866


    Members of the Wnt family of signaling molecules are important in cell specification and epithelial-mesenchymal interactions, and targeted gene deletion of Wnt-7a in mice results in complete absence of uterine glands and infertility. To assess potential roles of the Wnt family in human endometrium, an endocrine-responsive tissue, we investigated in the proliferative and secretory phases of the menstrual cycle, endometrial expression of several Wnt ligands (Wnt-2, Wnt-3, Wnt-4, Wnt-5a, Wnt-7a, and Wnt-8b), receptors [Frizzled (Fz)-6 and low-density lipoprotein receptor-related protein (LRP)-6], inhibitors [FrpHE and Dickkopf (Dkk)-1], and downstream effectors (Dishevelled-1, glycogen synthase kinase-3beta, and beta-catenin) by RT-PCR, real-time PCR and in situ hybridization. No significant menstrual cycle dependence of the Wnt ligands (except Wnt-3), receptors, or downstream effectors, was observed. Wnt-3 increased 4.7-fold in proliferative compared with secretory endometrium (P < 0.05). However, both inhibitors showed dramatic changes during the cycle, with 22.2-fold down-regulation (P < 0.05) of FrpHE and 234.3-fold up-regulation (P < 0.001) of Dkk-1 in the secretory, compared with the proliferative phase. In situ hybridization revealed cell-specific expression of different Wnt family genes in human endometrium. Wnt-7a was exclusively expressed in the luminal epithelium, and Fz-6 and beta-catenin were expressed in both epithelium and stroma, without any apparent change during the cycle. Both FrpHE and Dkk-1 expression were restricted to the stroma, during the proliferative and secretory phase, respectively. These unique expression patterns of Wnt family genes in different cell types of endometrium and the differential regulation of the inhibitors during the proliferative and secretory phase of the menstrual cycle strongly suggest functions for a Wnt signaling dialog between epithelial and stromal components in human endometrium. Also, they underscore the likely importance of this family during endometrial development, differentiation and implantation.

    View details for DOI 10.1210/jc.2003-030494

    View details for Web of Science ID 000184733200062

    View details for PubMedID 12915680

  • Comparative biology of the IGF system in endometrium, decidua, and placenta, and clinical implications for foetal growth and implantation disorders PLACENTA Nayak, N. R., Giudice, L. C. 2003; 24 (4): 281-296


    The insulin like growth factors and their binding proteins appear to play a central role during implantation and establishment of pregnancy in all species studied. Although there are similarities among species in the cell types that express IGFs and IGFBPs and their regulation during implantation and pregnancy, there are also significant differences. Understanding of the role of the IGF system in placental function in the human is of immense clinical importance, because serious complications of pregnancy such as intrauterine growth restriction and pre-eclampsia are thought to be associated with alterations in IGF system during early pregnancy and later in gestation. Research in laboratory and domestic animals, including transgenic and gene targeting studies in mice, has significantly improved our understanding of the role of IGF system in placental and foetal development. This paper reviews the diversity in the expression and regulation of IGF system in the decidua and placenta at the foetal-maternal interface in the human and different animal species, which may benefit in directing future studies in understanding of various complications of human pregnancy.

    View details for DOI 10.1053/plac.2002.0906

    View details for Web of Science ID 000182525500001

    View details for PubMedID 14626217

  • Vascular proliferation and vascular endothelial growth factor expression in the rhesus macaque endometrium JOURNAL OF CLINICAL ENDOCRINOLOGY & METABOLISM Nayak, N. R., Brenner, R. M. 2002; 87 (4): 1845-1855


    The relationship between vascular endothelial growth factor (VEGF) expression and the pattern of vascular proliferation in the rhesus macaque endometrium has not been studied. In this report, we used in situ hybridization to evaluate VEGF, VEGF receptor type 1 and VEGF receptor type 2 mRNA expression during hormonally regulated menstrual cycles in ovariectomized macaques. Proliferating endothelial cells were identified by a double immunocytochemistry procedure that detected Ki-67 antigen and von Willebrand factor in the same endothelial cells. One and 2 d after progesterone withdrawal (premenstrual), VEGF mRNA was up-regulated in the glands and stroma of the superficial endometrial zones, a finding that supports our previous suggestion that VEGF may play a role in the menstrual induction cascade. During the postmenstrual repair phase, the healing surface epithelium showed a further, dramatic increase in expression of VEGF mRNA, accompanied by strong increases in signals for VEGF receptor types 1 and 2 in multiple profiles of small blood vessels immediately below the surface epithelium. This finding implicates VEGF in the early angiogenic processes associated with endometrial healing and regeneration. Vascular endothelial proliferation persisted throughout the cycle in the upper endometrial zones and showed a dramatic estrogen- dependent peak during the midproliferative phase. This proliferative peak coincided with a peak in VEGF expression in the endometrial stroma. Endothelial proliferation was also significantly correlated with the degree of stromal VEGF expression during the proliferative and secretory stages of the cycle. These results implicate VEGF of stromal origin in endometrial vascular proliferation.

    View details for Web of Science ID 000174963100064

    View details for PubMedID 11932329

  • Progesterone antagonists increase androgen receptor expression in the rhesus macaque and human endometrium JOURNAL OF CLINICAL ENDOCRINOLOGY & METABOLISM Slayden, O. D., Nayak, N. R., Burton, K. A., Chwalisz, K., Cameron, S. T., Critchley, H. O., Baird, D. T., Brenner, R. M. 2001; 86 (6): 2668-2679


    Antiprogestins (APs) inhibit estradiol (E(2))-stimulated endometrial growth in women and nonhuman primates, but the mechanism of this "antiestrogenic" action is unknown. Here, we report that APs up-regulate endometrial androgen receptor (AR) in both women and macaques, an effect that might play a role in the antiproliferative effects of APs on the primate endometrium. In addition, because there are discrepancies in the literature on the regulation and localization of AR in the primate endometrium, we used both in situ hybridization and immunocytochemistry to evaluate hormonal influences on endometrial AR in women and macaques. In ovariectomized macaques, the following treatments were given for 4 weeks each: E(2) alone, E(2) + progesterone (P), E(2) + mifepristone (RU 486), and E(2) + P + RU 486. In women, samples were obtained during the normal menstrual cycle and after treatment with either RU 486 for 30 days at 2 mg/day, or after a single oral administration of 200 mg RU 486 on cycle day LH + 2. In macaques, E(2) significantly increased AR expression above vehicle controls; E(2) + RU 486 increased binding further; E(2) + P decreased AR binding; and E(2) + P + RU 486 treatment caused an intermediate elevation in AR binding. In macaques treated with E(2) alone, stromal AR staining was predominant, and P treatment suppressed that staining. E(2) + RU 486 or E(2) + P + RU 486 treatment produced a striking up-regulation of glandular epithelial AR staining and enhanced the stromal AR signal. In situ hybridization analyses confirmed the immunocytochemistry data. Similar induction of glandular AR staining and enhanced stromal AR staining were obtained in macaques treated with ZK 137 316 and ZK 230 211. During the natural cycle in women, stromal AR staining predominated and was greater in the proliferative than the late secretory phase. RU 486 treatment of women up-regulated glandular epithelial AR staining after either daily treatment for 30 days with 2 mg/day or after a single oral dose of 200 mg. In summary, endometrial AR was highest in the stroma during the human proliferative phase (or during E(2) treatment in macaques) and lowest during the late secretory phase in women (or after E(2) + P treatment in macaques). In both species, RU 486 induced AR expression in the glands and enhanced AR expression in stromal cells. Because androgens can antagonize E(2) action, enhanced endometrial AR expression induced by APs could play a role in the antiproliferative, "antiestrogenic" effects of APs in primates.

    View details for Web of Science ID 000169412000051

    View details for PubMedID 11397870

  • Estrogen receptor beta, but not estrogen receptor alpha, is present in the vascular endothelium of the human and nonhuman primate endometrium JOURNAL OF CLINICAL ENDOCRINOLOGY & METABOLISM Critchley, H. O., Brenner, R. M., Henderson, T. A., Williams, K., Nayak, N. R., Slayden, O. D., Millar, M. R., Saunders, P. T. 2001; 86 (3): 1370-1378


    Estrogen action is dependent upon the presence of specific ligand-activated receptors in target tissues. The aim of the present experiments was to compare the spatial and temporal pattern of expression of estrogen receptor beta (ERbeta) with that of ERalpha in full thickness endometrial samples (from the superficial to the basal zone) obtained from both women and rhesus macaques. Immunohistochemical localization with specific antibodies revealed that ERalpha and ERbeta were both expressed in nuclei of the glands and stroma. Consistent with previous studies, expression of ERalpha declined in the glands and stroma of the functionalis during the secretory phase. The luminal epithelium also displayed positive immunoreactivity for ERbeta. Expression of ERbeta declined in glandular cell nuclei, but not stroma, within the functionalis during the late secretory phase. Levels of expression of ERalpha and ERbeta in all cellular compartments remained unchanged in the basalis. Both receptor subtypes were detected on Western blots using proteins extracted from uterine samples obtained throughout the menstrual cycle. There was a striking contrast between the pattern of expression of ERalpha and ERbeta in the vascular endothelium and the perivascular cells surrounding endometrial blood vessels; only ERbeta was present in the endothelial cell population, although both forms of ER were expressed in perivascular cells. We conclude that estrogen action(s) within the vascular endothelium in the endometrium may be mediated via direct binding to the ERbeta isoform and that these cells could therefore be a target for agonists or antagonists that selectively target the beta form of the ER.

    View details for Web of Science ID 000167512000066

    View details for PubMedID 11238534

  • Progesterone withdrawal up-regulates vascular endothelial growth factor receptor type 2 in the superficial zone stroma of the human and macaque endometrium: Potential relevance to menstruation JOURNAL OF CLINICAL ENDOCRINOLOGY & METABOLISM Nayak, N. R., Critchley, H. O., Slayden, O. D., Menrad, A., Chwalisz, K., Baird, D. T., Brenner, R. M. 2000; 85 (9): 3442-3452


    Several reports indicate that vascular endothelial growth factor (VEGF) expression is increased in endometrial glands and stroma during the menstrual phase in the human endometrium. Here we report that VEGF receptor type 2 (KDR), normally expressed only in the vascular endothelium, was dramatically up-regulated in the stromal cells of the superficial endometrial zones during the premenstrual phase in both human and macaque endometrium. This increase was detectable by Northern analysis, in situ hybridization, and immunocytochemistry and was cell specific, zone specific, cycle phase specific, and VEGF receptor type specific. That is, it only occurred during the premenstrual/menstrual phase, did not occur in glandular epithelium, endothelium, or stromal cells of the deepest endometrial zones, and was not observed for VEGF receptor type 1. The upregulation of stromal KDR was induced by progesterone (P) withdrawal in both women and macaques, and adding back P 24 h after P withdrawal in macaques blocked stromal, but not vascular, endothelial KDR expression. Promatrix metalloproteinase-1 (MMP-1) was coordinately up-regulated in the same stromal cell population by P withdrawal. Because of reports that VEGF can enhance MMP expression, we hypothesize that VEGF-KDR interactions may influence MMP expression in the superficial zones of the primate endometrium during the premenstrual phase, and that these interactions play a role in the induction of menstruation.

    View details for Web of Science ID 000089166200073

    View details for PubMedID 10999847

  • Antinidatory effect of luteal phase administration of mifepristone (RU486) is associated with changes in endometrial prostaglandins during the implantation window CONTRACEPTION Nayak, N. R., SENGUPTA, J., Ghosh, D. 1998; 58 (2): 111-117


    Luteal phase administration of mifepristone provides a significant degree of pregnancy protection to monkeys and women. Among several proposed mediators of the antinidatory action of luteal phase mifepristone, prostaglandins (PG) at the endometrial level appear important, and was examined in the present study using the rhesus monkey as the primate model. To this end, the concentrations of PGE2 and PGF2 alpha in endometrium and the profiles of cyclooxygenase (COX) and 15-hydroxy prostaglandin dehydrogenase (PGDH) were examined in untreated control animals, in animals subjected to mifepristone treatment (2 mg/day) alone or along with diclofenac (25 mg/day), or along with a PGE1 analog (100 micrograms misoprostol), in animals subjected to diclofenac alone treatment, and in animals treated with misoprostol alone on cycle days 16, 17, and 18. Tissue samples were collected on day 20 of treatment cycles from animals with discernible corpora lutea. Early luteal phase treatment with diclofenac did not result in any remarkable change in endometrial prostaglandin concentrations, however, there was an increase in the profile of COX. Animals exposed to misoprostol in the prereceptive stage, on the other hand, exhibited decreased expression of endometrial COX. The concentrations of PGF2 alpha and PGE2, as well as the ratios of PGF2 alpha to PGE2 concentrations, were increased along with a decrease in COX and PGD in endometrial samples following luteal phase mifepristone treatment. Although the underlying cellular mechanism of regulation of COX and PGDH in mifepistone-treated endometrium remains to be examined, the decrease in PG catabolism through low PGDH may contribute to the increased PG and high ratio of PGF2 alpha to PGE2 in mifepristone-exposed endometrium. It is plausible that mifepristone action on endometrial cells is mediated by an altered ratio of PGF2 alpha to PGE2. Furthermore, it appears that the regulation of PG milieu by COX and PGDH activities in reproductive tissues is under complex regulatory mechanism and is temporarily correlated with specific developmental events.

    View details for Web of Science ID 000075917100007

    View details for PubMedID 9773266

  • Effects of luteal phase administration of mifepristone (RU486) and prostaglandin analogue or inhibitor on endometrium in the rhesus monkey HUMAN REPRODUCTION Nayak, N. R., Ghosh, D., SENGUPTA, J. 1998; 13 (4): 1047-1056


    Early luteal phase administration of a potent anti-progestin like mifepristone (RU486) inhibits blastocyst implantation and the establishment of pregnancy without marked changes in menstrual cyclicity and ovarian steroid hormone profiles; however, the underlying mechanism is not very clear. In the present study, a hypothesis that prostaglandins (PG) are involved in the anti-gestatory action of luteal phase mifepristone was tested. Endometrial changes in rhesus monkeys were examined following luteal phase administration of mifepristone, a prostaglandin synthesis inhibitor (diclofenac) and a prostaglandin analogue (misoprostol) either alone or in combination. Twenty-five monkeys were randomly assigned to six groups: group 1 (n = 4), normal control group; group 2 (n = 4), mifepristone (2 mg, daily, s.c.) treated group; group 3 (n = 4), diclofenac (25 mg, daily, i.m.) treated group; group 4 (n = 4), misoprostol (100 microg, daily, oral) treated group; group 5 (n = 5), mifepristone and diclofenac (same dosages as for groups 2 and 3) treated group; group 6 (n = 4), mifepristone and misoprostol (same dosages as for groups 2 and 4) treated group. All treatments were given to monkeys on days 16-18 of mated cycles and endometrial tissue samples were collected on day 20. With diclofenac alone (group 3), marginal changes were observed in glandular, stromal and vascular compartments, and there were few apoptotic bodies in gland cells; partial inhibition and delay in implantation was earlier reported. Significantly higher oestrogen receptor expression in glandular epithelial cells as compared with all other treatment groups was found after treatment with misoprostol alone (group 4) and was associated with normal fecundity. The anti-nidatory action of luteal phase antiprogestin treatment alone or in combination with diclofenac or misoprostol was associated with altered endometrial histometric features characterized by glandular apoptosis, regression in secretory functions, decreased oedema, extravasation and a higher degree of stromal leukocytic infiltration. In these three groups (groups 2, 5 and 6) receptors for oestrogen and progesterone receptors were significantly higher in stromal cells, and lower in vascular cells, while glandular cells showed significantly higher progesterone receptors compared with the control group. The anti-nidatory activity of mifepristone and associated endometrial changes could not be accentuated or attenuated with co-administration of PGE or diclofenac, nor could these be mimicked by these agents alone.

    View details for Web of Science ID 000074269700049

    View details for PubMedID 9619569

  • Effect of follicular phase administration of mifepristone (RU486) on blastocyst implantation in the rhesus monkey CONTRACEPTION Ghosh, D., Nayak, N. R., SENGUPTA, J. 1997; 56 (2): 117-122


    In the present study our aim was to test two hypotheses: 1) inhibition of preovulatory phase progesterone action can inhibit or delay ovulation, and 2) inhibition of preovulatory phase progesterone action can inhibit postovulatory phase endometrial receptivity for blastocyst implantation. Female rhesus monkeys showing normal cycle lengths were randomly assigned to two groups: group 1 (n = 5) and group 2 (n = 7). The pretreatment cycles were monitored for ovulatory pattern and, in treatment cycles, females were allowed to cohabit with males from cycle days 6 to 28; group 1 animals received vehicle alone, and group 2 animals received mifepristone (RU486, subcutaneously), 1 mg/animal 3 consecutive cycle days (days 7, 8, and 9 for 26-day pretreatment cycle length; and days 8, 9, and 10 for 28-day pretreatment cycle length). Follicular phase mifepristone resulted in a delay of ovulation (p < 0.01) when compared with pooled data of pretreatment and treatment cycles of group 1 and pretreatment cycles of group 2. Despite delay of ovulation, there was only a 20% decrease in the incidence of pregnancy in group 2 as compared with that in group 1. However, a delay (p < 0.05) in the appearance of CG was noted in follicular phase mifepristone-treated cycles as compared with control treatment cycles. On the other hand, ovulation could not be detected in three monkeys in group 2; and, of these, two cycles were extended, but all three cycles were negative for CG. These results support earlier reports that follicular phase mifepristone can inhibit or disrupt follicular maturation, and delay ovulation. However, follicular phase mifepristone failed to inhibit implantation, because gonadal hormones, including progesterone, resume normal functions once ovulation takes place.

    View details for Web of Science ID A1997XY28100009

    View details for PubMedID 9315421

  • Serum concentrations of oestradiol-17 beta, progesterone, relaxin and chorionic gonadotrophin during blastocyst implantation in natural pregnancy cycle and in embryo transfer cycle in the rhesus monkey HUMAN REPRODUCTION Ghosh, D., Stewart, D. R., Nayak, N. R., Lasley, B. L., Overstreet, J. W., Hendrickx, A. G., SENGUPTA, J. 1997; 12 (5): 914-920


    The present study was undertaken to assess the temporal association between the profiles of serum concentrations of oestradiol-17beta, progesterone, chorionic gonadotrophin (CG) and relaxin in pregnancies established naturally, and after embryo transfer, as well as in failed pregnancies in rhesus monkeys. In naturally mated cycles (group 1) a conception rate of 75% was obtained. In group 1, the mean day of CG detection in serum was 11.5 +/- 1.9 day post-ovulation, and for relaxin, 9.0 +/- 2.5 day post-ovulation. In group 2, embryo transfer to synchronous, non-mated surrogate recipients was performed; seven embryo transfer cycles yielded three pregnancies which were allowed to continue to term and normal infants were delivered. In embryo transfer cycles the mean day of CG detection was 14.8 +/- 1.8 day post-ovulation, and for relaxin, 11.4 +/- 2.6 day post-ovulation. A delay of about 3 days was observed in the appearance in circulation of CG (P < 0.05) and also of relaxin (P < 0.05) between natural mated and embryo transfer conception cycles. Significant differences (P < 0.05 for progesterone and P < 0.03 for oestradiol) were obtained for the areas under the curves for progesterone and oestradiol between days 12 and 16 in conception cycles compared with failed pregnancies. These data provide the first observation of the normal hormonal signals associated with maternal recognition of transferred embryos during the peri-implantation period, and suggest that the use of such an experimental primate embryo transfer model may help to elucidate components of maternal and embryonic signal-response mechanisms during embryo implantation.

    View details for Web of Science ID A1997XD46000010

    View details for PubMedID 9194639

  • Hormonal requirement for blastocyst implantation and a new approach for anti-implantation strategy. Indian journal of physiology and pharmacology Ghosh, D., Nayak, N. R., Kumar, P. G., Dhara, S., SENGUPTA, J. 1997; 41 (2): 101-108


    There is a growing awareness of a need for developing novel methods of contraceptive technology which should not only be effective in providing protection against conception but also take into consideration the reproductive health issues confronting men and women. This paper considers the process of embryo implantation as one such potential target. The hormonal basis of embryo implantation in primates has been discussed to indicate that progesterone, and not estrogen, from ovarian source is the primary determinant of embryo-endometrial maturation and their synchronization for implantation. Thus, low dose administration of the anti-progesterone, mifepristone, during early luteal phase has been shown to be an effective anti-implantation approach to for fertility control. Furthermore, the dissociation of endometrial-hormonal synchrony at the time of blastocyst implantation following the post-ovulatory mifepristone administration has been shown to be the physiological basis of its anti-implantation effect with undisturbed circulatory hormone profiles and ovarian functions. Further studies are required to appreciate the full potential and to mollify the limitations of this approach.

    View details for PubMedID 9142552

  • Anti-implantation activity of luteal phase mifepristone administration is not mimicked by prostaglandin synthesis inhibitor or prostaglandin analogue in the rhesus monkey CONTRACEPTION Nayak, N. R., Ghosh, D., Lasley, B. L., SENGUPTA, J. 1997; 55 (2): 103-114


    The use of mifepristone as an anti-implantation agent in the primate has been explored in the rhesus monkey with two specific aims: (i) to determine the contraceptive efficacy of very low-dose mifepristone administered on mated cycle days 16, 17, and 18; and (ii) to test the hypothesis that alteration in endometrial prostaglandin milieu by using either prostaglandin analogue or prostaglandin synthesis inhibitor can intervene the antifertility effect induced by mifepristone. Thirty female monkeys were randomly assigned to one of the six treatment groups. Five monkeys in the control group (group 1) were subjected to mating during cycle days 8-22. Four out of five monkeys became pregnant in the first mated cycle (80%) with detection of serum mCG by 12.7 +/- 1.5 days after ovulation. In group 2, 12 mated cycles were studied in five monkeys, mifepristone [RU486, 2 mg/day/animal, s.c. in 1 ml vehicle (1:4, benzyl benzoate:olive oil, v/v)] was given on cycle days 16, 17, and 18. In this group, no pregnancy was observed, thus providing complete pregnancy protection. Though there was an apparent extension of treatment cycle lengths in five cases with no incidence of inter-menstrual bleeding or spotting, there were no significant changes in serum estradiol (E) and progesterone (P). In group 3, four monkeys received prostaglandin (PG) synthesis inhibitor, diclofenac sodium (D, 25 mg/day/animal, i.m.) on cycle days 16, 17, and 18 in seven ovulatory menstrual cycles. Four of these cycles (57%) resulted in normal pregnancies; however, mCG detection (16.8 +/- 1.2 days after ovulation) was significantly (p < 0.05) delayed as compared to group 1. In group 4, four monkeys received 100 micrograms misoprostol (M), a PGE1 analogue, by gavage on mated cycle days 16, 17, and 18. Four pregnancies occurred in five treatment cycles (80%) with normal profiles of serum E and Pi mCG was first detected 13.2 +/- 1.7 days after ovulation. In group 5, seven monkeys received same dosages of RU486 and D on mated cycle days 16, 17, and 18. One hundred percent pregnancy protection was observed with luteal phase lengthening in eight treatment cycles but with unaltered E and P profiles. In group 6, five monkeys in nine treatment cycles received same dosages of RU486 and M on mated cycle days 16, 17, and 18. One pregnancy occurred; evaluation of E and P levels showed that the drug was given in the preovulatory period, which delayed ovulation and implantation, as mCG was detected 19 days post-ovulation. A delay in vaginal bleeding was observed in four treatment cycles with unaltered E and P profiles. Low-dose mifepristone appears to be a potential candidate for luteal phase and post-coital emergency contraception. However, the hypothesis that altered endometrial prostaglandin milieu may be responsible for mediating the anti-implantation effect of RU486 does not appear to be tenable based on our results in the rhesus monkey.

    View details for Web of Science ID A1997WM95200008

    View details for PubMedID 9071520

  • A comparison of vessel sensitivity and vessel constant in oxygen uptake determination with pure oxygen and air as gaseous media. Indian journal of experimental biology Misra, M. S., Nayak, N. R., Kundu, A. K. 1992; 30 (5): 454-456


    Air proved to be a superior gaseous medium to pure oxygen used for oxygen uptake study in the Warburg apparatus Recording of volume change (vessel sensitivity method) was the only correct method of recording the oxygen uptake. It is concluded that the volume change method should be followed for recording oxygen uptake by Warburg apparatus and pure oxygen should not be used as a gaseous medium.

    View details for PubMedID 1459626

  • Relation between volume change and pressure change in oxygen uptake study using Warburg apparatus. Indian journal of experimental biology Misra, M. S., Nayak, N. R., Kundu, A. K. 1991; 29 (9): 872-874


    Taking oxygen and air as gaseous media oxygen uptake study was carried out recording delta V and corresponding delta P. From these data the quantity of oxygen consumed was calculated. It was concluded that delta V x vessel sensitivity x 2 = delta P x vessel constant. Recording of volume change in oxygen uptake study has been advocated.

    View details for PubMedID 1794874

Conference Proceedings

  • Premenstrual and menstrual changes in the macaque and human endometrium - Relevance to endometriosis Brenner, R. M., Nayak, N. R., Slayden, O. D., Critchley, H. O., Kelly, R. W. NEW YORK ACAD SCIENCES. 2002: 60-74


    According to current theory, endometriosis is initiated during retrograde menstruation when menstrual fragments flow out of the fimbriated end of the fallopian tubes and become established on the ovarian surface or other sites in the peritoneal cavity. In recent years, new data have accumulated on the properties of menstruating tissue itself, and several laboratories agree that this tissue is rich in matrix metalloproteinases (MMPs) that may facilitate endometriotic implantation. Recently, we found that vascular endothelial growth factor (VEGF) and its receptor VEGFR-2 (KDR) were dramatically upregulated in the stromal cells of the superficial endometrial zones by progesterone (P) withdrawal during the premenstrual phase. A unique role of VEGF at this stage of the cycle may be to stimulate MMP expression in stromal cells because VEGF, KDR, and MMPs were all coordinately induced in these cells in the superficial zone of the primate endometrium by P withdrawal. The rich content of MMPs and VEGF in the menstrual fragments could facilitate attachment and angiogenesis of menstrual fragments in ectopic sites. In addition, a variety of chemokines, cytokines, and cellular regulators are induced by P withdrawal in the premenstrual human endometrium. These include NFKB, prostaglandins, interleukin-8 (IL-8), cyclooxygenase-2 (COX-2), and monocyte chemotactic peptide-1 (MCP-1), among others. The perivascular expression of several of these factors may facilitate the rapid invasion of leukocytes into the endometrium, especially in the superficial zones. Consequently, menstrual fragments may be rich in IL-8 and MCP-1, both of which would add to the angiogenic potential of such fragments in ectopic sites. In sum, menstrual tissue is rich in VEGF, KDR, MMPs, leukocytes, chemokines, cytokines, and prostaglandins, all factors that may facilitate attachment and angiogenesis when menstrual fragments exit from the tubes and implant on pelvic sites. Additional research on these and other factors in premenstrual and menstrual endometrium may deepen our understanding of both the establishment and progression of this debilitating disease.

    View details for Web of Science ID 000175883100006

    View details for PubMedID 11949966

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