Professor of Surgery (Vascular Surgery) and of Medicine (Cardiovascular)

Publications

  • Clustering cancers by shared transcriptional risk reveals novel targets for cancer therapy. Molecular cancer Gao, H., Baylis, R. A., Luo, L., Kojima, Y., Bell, C. F., Ross, E. G., Wang, F., Leeper, N. J. 2022; 21 (1): 116

    View details for DOI 10.1186/s12943-022-01592-y

    View details for PubMedID 35585548

  • The pleiotropic benefits of statins include the ability to reduce CD47 and amplify the effect of pro-efferocytic therapies in atherosclerosis. Nature cardiovascular research Jarr, K., Ye, J., Kojima, Y., Ye, Z., Gao, H., Schmid, S., Luo, L., Baylis, R. A., Lotfi, M., Lopez, N., Eberhard, A. V., Smith, B. R., Weissman, I. L., Maegdefessel, L., Leeper, N. J. 2022; 1 (3): 253-262

    Abstract

    The pleiotropic benefits of statins may result from their impact on vascular inflammation. The molecular process underlying this phenomenon is not fully elucidated. Here, RNA sequencing designed to investigate gene expression patterns following CD47-SIRPalpha inhibition identifies a link between statins, efferocytosis, and vascular inflammation. In vivo and in vitro studies provide evidence that statins augment programmed cell removal by inhibiting the nuclear translocation of NFkappaB1 p50 and suppressing the expression of the critical 'don't eat me' molecule, CD47. Statins amplify the phagocytic capacity of macrophages, and thus the anti-atherosclerotic effects of CD47-SIRPalpha blockade, in an additive manner. Analyses of clinical biobank specimens suggest a similar link between statins and CD47 expression in humans, highlighting the potential translational implications. Taken together, our findings identify efferocytosis and CD47 as pivotal mediators of statin pleiotropy. In turn, statins amplify the anti-atherosclerotic effects of pro-phagocytic therapies independently of any lipid-lowering effect.

    View details for DOI 10.1038/s44161-022-00023-x

    View details for PubMedID 35990913

  • Bench-to-Bedside in Vascular Medicine: Optimizing the Translational Pipeline for Patients With Peripheral Artery Disease. Circulation research Alsaigh, T., Di Bartolo, B. A., Mulangala, J., Figtree, G. A., Leeper, N. J. 2021; 128 (12): 1927-1943

    Abstract

    Peripheral arterial disease is a growing worldwide problem with a wide spectrum of clinical severity and is projected to consume >

  • Effect of CD47 Blockade on Vascular Inflammation. The New England journal of medicine Jarr, K. U., Nakamoto, R. n., Doan, B. H., Kojima, Y. n., Weissman, I. L., Advani, R. H., Iagaru, A. n., Leeper, N. J. 2021; 384 (4): 382–83

    View details for DOI 10.1056/NEJMc2029834

    View details for PubMedID 33503349

  • Knockout of the Murine Ortholog to the Human 9p21 Coronary Artery Disease Locus Leads to Smooth Muscle Cell Proliferation, Vascular Calcification, and Advanced Atherosclerosis. Circulation Kojima, Y., Ye, J., Nanda, V., Wang, Y., Flores, A. M., Jarr, K., Tsantilas, P., Guo, L., Finn, A. V., Virmani, R., Leeper, N. J. 2020; 141 (15): 1274–76

    View details for DOI 10.1161/CIRCULATIONAHA.119.043413

    View details for PubMedID 32282248

  • Pro-efferocytic nanoparticles are specifically taken up by lesional macrophages and prevent atherosclerosis. Nature nanotechnology Flores, A. M., Hosseini-Nassab, N. n., Jarr, K. U., Ye, J. n., Zhu, X. n., Wirka, R. n., Koh, A. L., Tsantilas, P. n., Wang, Y. n., Nanda, V. n., Kojima, Y. n., Zeng, Y. n., Lotfi, M. n., Sinclair, R. n., Weissman, I. L., Ingelsson, E. n., Smith, B. R., Leeper, N. J. 2020

    Abstract

    Atherosclerosis is the process that underlies heart attack and stroke. A characteristic feature of the atherosclerotic plaque is the accumulation of apoptotic cells in the necrotic core. Prophagocytic antibody-based therapies are currently being explored to stimulate the phagocytic clearance of apoptotic cells; however, these therapies can cause off-target clearance of healthy tissues, which leads to toxicities such as anaemia. Here we developed a macrophage-specific nanotherapy based on single-walled carbon nanotubes loaded with a chemical inhibitor of the antiphagocytic CD47-SIRPα signalling axis. We demonstrate that these single-walled carbon nanotubes accumulate within the atherosclerotic plaque, reactivate lesional phagocytosis and reduce the plaque burden in atheroprone apolipoprotein-E-deficient mice without compromising safety, and thereby overcome a key translational barrier for this class of drugs. Single-cell RNA sequencing analysis reveals that prophagocytic single-walled carbon nanotubes decrease the expression of inflammatory genes linked to cytokine and chemokine pathways in lesional macrophages, which demonstrates the potential of 'Trojan horse' nanoparticles to prevent atherosclerotic cardiovascular disease.

    View details for DOI 10.1038/s41565-019-0619-3

    View details for PubMedID 31988506

  • Clonally expanding smooth muscle cells promote atherosclerosis by escaping efferocytosis and activating the complement cascade. Proceedings of the National Academy of Sciences of the United States of America Wang, Y. n., Nanda, V. n., Direnzo, D. n., Ye, J. n., Xiao, S. n., Kojima, Y. n., Howe, K. L., Jarr, K. U., Flores, A. M., Tsantilas, P. n., Tsao, N. n., Rao, A. n., Newman, A. A., Eberhard, A. V., Priest, J. R., Ruusalepp, A. n., Pasterkamp, G. n., Maegdefessel, L. n., Miller, C. L., Lind, L. n., Koplev, S. n., Björkegren, J. L., Owens, G. K., Ingelsson, E. n., Weissman, I. L., Leeper, N. J. 2020

    Abstract

    Atherosclerosis is the process underlying heart attack and stroke. Despite decades of research, its pathogenesis remains unclear. Dogma suggests that atherosclerotic plaques expand primarily via the accumulation of cholesterol and inflammatory cells. However, recent evidence suggests that a substantial portion of the plaque may arise from a subset of "dedifferentiated" vascular smooth muscle cells (SMCs) which proliferate in a clonal fashion. Herein we use multicolor lineage-tracing models to confirm that the mature SMC can give rise to a hyperproliferative cell which appears to promote inflammation via elaboration of complement-dependent anaphylatoxins. Despite being extensively opsonized with prophagocytic complement fragments, we find that this cell also escapes immune surveillance by neighboring macrophages, thereby exacerbating its relative survival advantage. Mechanistic studies indicate this phenomenon results from a generalized opsonin-sensing defect acquired by macrophages during polarization. This defect coincides with the noncanonical up-regulation of so-called don't eat me molecules on inflamed phagocytes, which reduces their capacity for programmed cell removal (PrCR). Knockdown or knockout of the key antiphagocytic molecule CD47 restores the ability of macrophages to sense and clear opsonized targets in vitro, allowing for potent and targeted suppression of clonal SMC expansion in the plaque in vivo. Because integrated clinical and genomic analyses indicate that similar pathways are active in humans with cardiovascular disease, these studies suggest that the clonally expanding SMC may represent a translational target for treating atherosclerosis.

    View details for DOI 10.1073/pnas.2006348117

    View details for PubMedID 32541024

  • Clinical and Genetic Determinants of Varicose Veins Prospective, Community-Based Study of approximate to 500 000 Individuals CIRCULATION Fukaya, E., Flores, A. M., Lindholm, D., Gustafsson, S., Zanetti, D., Ingelsson, E., Leeper, N. J. 2018; 138 (25): 2869–80
  • Proefferocytic Therapy Promotes Transforming Growth Factor-beta Signaling and Prevents Aneurysm Formation CIRCULATION Kojima, Y., Werner, N., Ye, J., Nanda, V., Tsao, N., Wang, Y., Flores, A. M., Miller, C. L., Weissman, I., Deng, H., Xu, B., Dalman, R. L., Eken, S. M., Pelisek, J., Li, Y., Maegdefessel, L., Leeper, N. J. 2018; 137 (7): 750–53

    View details for PubMedID 29440201

    View details for PubMedCentralID PMC5819616

  • The Role of Efferocytosis in Atherosclerosis CIRCULATION Kojima, Y., Weissman, I. L., Leeper, N. J. 2017; 135 (5): 476-489

    Abstract

    The necrotic core has long been a hallmark of the vulnerable atherosclerotic plaque. Although apoptotic cells are cleared quickly in almost all other tissue beds, their removal appears to be significantly impaired in the diseased blood vessel. Emerging evidence indicates that this phenomenon is caused by a defect in efferocytosis, the process by which apoptotic tissue is recognized for engulfment by phagocytic cells such as macrophages. Genetic and experimental data suggest that efferocytosis is impaired during atherogenesis caused by dysregulation of so-called eat me ligands, which govern the edibility of cells undergoing programmed cell death. The following is a summary of recent data indicating that efferocytosis is a major unappreciated driver of lesion expansion but also a reversible defect that can potentially be targeted as a means to prevent plaque progression.

    View details for DOI 10.1161/CIRCULATIONAHA.116.025684

    View details for Web of Science ID 000393716200009

    View details for PubMedID 28137963

    View details for PubMedCentralID PMC5302553

  • Canagliflozin and Cardiovascular and Renal Events in Type 2 Diabetes. The New England journal of medicine Neal, B. n., Perkovic, V. n., Mahaffey, K. W., de Zeeuw, D. n., Fulcher, G. n., Erondu, N. n., Shaw, W. n., Law, G. n., Desai, M. n., Matthews, D. R. 2017; 377 (7): 644–57

    Abstract

    Background Canagliflozin is a sodium-glucose cotransporter 2 inhibitor that reduces glycemia as well as blood pressure, body weight, and albuminuria in people with diabetes. We report the effects of treatment with canagliflozin on cardiovascular, renal, and safety outcomes. Methods The CANVAS Program integrated data from two trials involving a total of 10,142 participants with type 2 diabetes and high cardiovascular risk. Participants in each trial were randomly assigned to receive canagliflozin or placebo and were followed for a mean of 188.2 weeks. The primary outcome was a composite of death from cardiovascular causes, nonfatal myocardial infarction, or nonfatal stroke. Results The mean age of the participants was 63.3 years, 35.8% were women, the mean duration of diabetes was 13.5 years, and 65.6% had a history of cardiovascular disease. The rate of the primary outcome was lower with canagliflozin than with placebo (occurring in 26.9 vs. 31.5 participants per 1000 patient-years; hazard ratio, 0.86; 95% confidence interval [CI], 0.75 to 0.97; P<0.001 for noninferiority; P=0.02 for superiority). Although on the basis of the prespecified hypothesis testing sequence the renal outcomes are not viewed as statistically significant, the results showed a possible benefit of canagliflozin with respect to the progression of albuminuria (hazard ratio, 0.73; 95% CI, 0.67 to 0.79) and the composite outcome of a sustained 40% reduction in the estimated glomerular filtration rate, the need for renal-replacement therapy, or death from renal causes (hazard ratio, 0.60; 95% CI, 0.47 to 0.77). Adverse reactions were consistent with the previously reported risks associated with canagliflozin except for an increased risk of amputation (6.3 vs. 3.4 participants per 1000 patient-years; hazard ratio, 1.97; 95% CI, 1.41 to 2.75); amputations were primarily at the level of the toe or metatarsal. Conclusions In two trials involving patients with type 2 diabetes and an elevated risk of cardiovascular disease, patients treated with canagliflozin had a lower risk of cardiovascular events than those who received placebo but a greater risk of amputation, primarily at the level of the toe or metatarsal. (Funded by Janssen Research and Development; CANVAS and CANVAS-R ClinicalTrials.gov numbers, NCT01032629 and NCT01989754 , respectively.).

    View details for PubMedID 28605608

  • CD47-blocking antibodies restore phagocytosis and prevent atherosclerosis. Nature Kojima, Y., Volkmer, J., McKenna, K., Civelek, M., Lusis, A. J., Miller, C. L., DiRenzo, D., Nanda, V., Ye, J., Connolly, A. J., Schadt, E. E., Quertermous, T., Betancur, P., Maegdefessel, L., Matic, L. P., Hedin, U., Weissman, I. L., Leeper, N. J. 2016; 536 (7614): 86-90

    Abstract

    Atherosclerosis is the disease process that underlies heart attack and stroke. Advanced lesions at risk of rupture are characterized by the pathological accumulation of diseased vascular cells and apoptotic cellular debris. Why these cells are not cleared remains unknown. Here we show that atherogenesis is associated with upregulation of CD47, a key anti-phagocytic molecule that is known to render malignant cells resistant to programmed cell removal, or 'efferocytosis'. We find that administration of CD47-blocking antibodies reverses this defect in efferocytosis, normalizes the clearance of diseased vascular tissue, and ameliorates atherosclerosis in multiple mouse models. Mechanistic studies implicate the pro-atherosclerotic factor TNF-α as a fundamental driver of impaired programmed cell removal, explaining why this process is compromised in vascular disease. Similar to recent observations in cancer, impaired efferocytosis appears to play a pathogenic role in cardiovascular disease, but is not a fixed defect and may represent a novel therapeutic target.

    View details for PubMedID 27437576

  • CDKN2B Regulates TGFß Signaling and Smooth Muscle Cell Investment of Hypoxic Neovessels. Circulation research Nanda, V., Downing, K. P., Ye, J., Xiao, S., Kojima, Y., Spin, J. M., DiRenzo, D., Nead, K. T., Connolly, A. J., Dandona, S., Perisic, L., Hedin, U., Maegdefessel, L., Dalman, J., Guo, L., Zhao, X., Kolodgie, F. D., Virmani, R., Davis, H. R., Leeper, N. J. 2016; 118 (2): 230-240

    Abstract

    Genetic variation at the chromosome 9p21 cardiovascular risk locus has been associated with peripheral artery disease, but its mechanism remains unknown.To determine whether this association is secondary to an increase in atherosclerosis, or it is the result of a separate angiogenesis-related mechanism.Quantitative evaluation of human vascular samples revealed that carriers of the 9p21 risk allele possess a significantly higher burden of immature intraplaque microvessels than carriers of the ancestral allele, irrespective of lesion size or patient comorbidity. To determine whether aberrant angiogenesis also occurs under nonatherosclerotic conditions, we performed femoral artery ligation surgery in mice lacking the 9p21 candidate gene, Cdkn2b. These animals developed advanced hindlimb ischemia and digital autoamputation, secondary to a defect in the capacity of the Cdkn2b-deficient smooth muscle cell to support the developing neovessel. Microarray studies identified impaired transforming growth factor β (TGFβ) signaling in cultured cyclin-dependent kinase inhibitor 2B (CDKN2B)-deficient cells, as well as TGFβ1 upregulation in the vasculature of 9p21 risk allele carriers. Molecular signaling studies indicated that loss of CDKN2B impairs the expression of the inhibitory factor, SMAD-7, which promotes downstream TGFβ activation. Ultimately, this manifests in the upregulation of a poorly studied effector molecule, TGFβ1-induced-1, which is a TGFβ-rheostat known to have antagonistic effects on the endothelial cell and smooth muscle cell. Dual knockdown studies confirmed the reversibility of the proposed mechanism, in vitro.These results suggest that loss of CDKN2B may not only promote cardiovascular disease through the development of atherosclerosis but may also impair TGFβ signaling and hypoxic neovessel maturation.

    View details for DOI 10.1161/CIRCRESAHA.115.307906

    View details for PubMedID 26596284

    View details for PubMedCentralID PMC4740238

  • The Genetic Basis of Peripheral Arterial Disease Current Knowledge, Challenges, and Future Directions CIRCULATION RESEARCH Kullo, I. J., Leeper, N. J. 2015; 116 (9): 1551-1560

    Abstract

    Several risk factors for atherosclerotic peripheral arterial disease (PAD), such as dyslipidemia, diabetes mellitus, and hypertension, are heritable. However, predisposition to PAD may be influenced by genetic variants acting independently of these risk factors. Identification of such genetic variants will provide insights into underlying pathophysiologic mechanisms and facilitate the development of novel diagnostic and therapeutic approaches. In contrast to coronary heart disease, relatively few genetic variants that influence susceptibility to PAD have been discovered. This may be, in part, because of greater clinical and genetic heterogeneity in PAD. In this review, we (1) provide an update on the current state of knowledge about the genetic basis of PAD, including results of family studies and candidate gene, linkage as well as genome-wide association studies; (2) highlight the challenges in investigating the genetic basis of PAD and possible strategies to overcome these challenges; and (3) discuss the potential of genome sequencing, RNA sequencing, differential gene expression, epigenetic profiling, and systems biology in increasing our understanding of the molecular genetics of PAD.

    View details for DOI 10.1161/CIRCRESAHA.116.303518

    View details for Web of Science ID 000353383600005

    View details for PubMedID 25908728

    View details for PubMedCentralID PMC4410432

  • Cyclin-dependent kinase inhibitor 2B regulates efferocytosis and atherosclerosis JOURNAL OF CLINICAL INVESTIGATION Kojima, Y., Downing, K., Kundu, R., Miller, C., Dewey, F., Lancero, H., Raaz, U., Perisic, L., Hedin, U., Schadt, E., Maegdefessel, L., Quertermous, T., Leeper, N. J. 2014; 124 (3): 1083-1097

    Abstract

    Genetic variation at the chromosome 9p21 risk locus promotes cardiovascular disease; however, it is unclear how or which proteins encoded at this locus contribute to disease. We have previously demonstrated that loss of one candidate gene at this locus, cyclin-dependent kinase inhibitor 2B (Cdkn2b), in mice promotes vascular SMC apoptosis and aneurysm progression. Here, we investigated the role of Cdnk2b in atherogenesis and found that in a mouse model of atherosclerosis, deletion of Cdnk2b promoted advanced development of atherosclerotic plaques composed of large necrotic cores. Furthermore, human carriers of the 9p21 risk allele had reduced expression of CDKN2B in atherosclerotic plaques, which was associated with impaired expression of calreticulin, a ligand required for activation of engulfment receptors on phagocytic cells. As a result of decreased calreticulin, CDKN2B-deficient apoptotic bodies were resistant to efferocytosis and not efficiently cleared by neighboring macrophages. These uncleared SMCs elicited a series of proatherogenic juxtacrine responses associated with increased foam cell formation and inflammatory cytokine elaboration. The addition of exogenous calreticulin reversed defects associated with loss of Cdkn2b and normalized engulfment of Cdkn2b-deficient cells. Together, these data suggest that loss of CDKN2B promotes atherosclerosis by increasing the size and complexity of the lipid-laden necrotic core through impaired efferocytosis.

    View details for DOI 10.1172/JCI70391

    View details for Web of Science ID 000332347700028

    View details for PubMedID 24531546

  • Alternative Ankle-Brachial Index Method Identifies Additional At-Risk Individuals JOURNAL OF THE AMERICAN COLLEGE OF CARDIOLOGY Nead, K. T., Cooke, J. P., Olin, J. W., Leeper, N. J. 2013; 62 (6): 553-559

    Abstract

    OBJECTIVES: To determine whether utilization of an alternative ankle-brachial index (ABI) calculation method improves mortality risk prediction compared to traditional methods. BACKGROUND: The ABI is used to diagnose peripheral arterial disease (PAD), and to identify those at risk for cardiovascular events. Traditionally, the ABI is calculated using the higher of the dorsalis pedis and posterior tibial ankle arteries. Studies directly comparing calculation methods are limited. METHODS: The ABI was calculated at baseline in 1,413 study participants undergoing non-emergent coronary angiography subsequently followed for all-cause and cardiovascular mortality. There were 224 individuals assigned to the traditional-PAD group (ABI < 0.90) using the traditional ABI method. Of those remaining, an alternative ABI method utilizing the lower of the two ankle pressures assigned 282 patients to the alternative-PAD group. The 862 individuals not assigned to PAD by either method were the no-PAD group. RESULTS: There were 163 mortalities during a median follow-up of 5.0 years. Adjusted Cox regression models showed that the alternative-PAD group had an increased risk for all-cause (HR=1.49; 95% CI, 1.01-2.19) and cardiovascular mortality (HR=3.21; 95% CI, 1.53-6.37) versus the no-PAD group. Additionally, in the no-PAD group, there was an 11% (HR=1.11; 95% CI, 1.05-1.17) increased risk of all-cause mortality per 1mm Hg increased difference between the left and right brachial systolic pressures. CONCLUSION: The implementation of an alternative ABI method and use of the brachial difference identifies individuals at an increased risk for mortality who are currently missed using traditional ABI methods. Current ABI protocols may need to be evaluated.

    View details for DOI 10.1016/j.jacc.2013.04.061

    View details for Web of Science ID 000322524300011

    View details for PubMedID 23707317

  • Loss of CDKN2B promotes p53-dependent smooth muscle cell apoptosis and aneurysm formation. Arteriosclerosis, thrombosis, and vascular biology Leeper, N. J., Raiesdana, A., Kojima, Y., Kundu, R. K., Cheng, H., Maegdefessel, L., Toh, R., Ahn, G., Ali, Z. A., Anderson, D. R., Miller, C. L., Roberts, S. C., Spin, J. M., de Almeida, P. E., Wu, J. C., Xu, B., Cheng, K., Quertermous, M., Kundu, S., Kortekaas, K. E., Berzin, E., Downing, K. P., Dalman, R. L., Tsao, P. S., Schadt, E. E., Owens, G. K., Quertermous, T. 2013; 33 (1): e1-e10

    Abstract

    Genomewide association studies have implicated allelic variation at 9p21.3 in multiple forms of vascular disease, including atherosclerotic coronary heart disease and abdominal aortic aneurysm. As for other genes at 9p21.3, human expression quantitative trait locus studies have associated expression of the tumor suppressor gene CDKN2B with the risk haplotype, but its potential role in vascular pathobiology remains unclear.Here we used vascular injury models and found that Cdkn2b knockout mice displayed the expected increase in proliferation after injury, but developed reduced neointimal lesions and larger aortic aneurysms. In situ and in vitro studies suggested that these effects were attributable to increased smooth muscle cell apoptosis. Adoptive bone marrow transplant studies confirmed that the observed effects of Cdkn2b were mediated through intrinsic vascular cells and were not dependent on bone marrow-derived inflammatory cells. Mechanistic studies suggested that the observed increase in apoptosis was attributable to a reduction in MDM2 and an increase in p53 signaling, possibly due in part to compensation by other genes at the 9p21.3 locus. Dual inhibition of both Cdkn2b and p53 led to a reversal of the vascular phenotype in each model.These results suggest that reduced CDKN2B expression and increased smooth muscle cell apoptosis may be one mechanism underlying the 9p21.3 association with aneurysmal disease.

    View details for DOI 10.1161/ATVBAHA.112.300399

    View details for PubMedID 23162013

  • MicroRNA-21 Blocks Abdominal Aortic Aneurysm Development and Nicotine-Augmented Expansion SCIENCE TRANSLATIONAL MEDICINE Maegdefessel, L., Azuma, J., Toh, R., Deng, A., Merk, D. R., Raiesdana, A., Leeper, N. J., Raaz, U., Schoelmerich, A. M., McConnell, M. V., Dalman, R. L., Spin, J. M., Tsao, P. S. 2012; 4 (122)

    Abstract

    Identification and treatment of abdominal aortic aneurysm (AAA) remains among the most prominent challenges in vascular medicine. MicroRNAs are crucial regulators of cardiovascular pathology and represent possible targets for the inhibition of AAA expansion. We identified microRNA-21 (miR-21) as a key modulator of proliferation and apoptosis of vascular wall smooth muscle cells during development of AAA in two established murine models. In both models (AAA induced by porcine pancreatic elastase or infusion of angiotensin II), miR-21 expression increased as AAA developed. Lentiviral overexpression of miR-21 induced cell proliferation and decreased apoptosis in the aortic wall, with protective effects on aneurysm expansion. miR-21 overexpression substantially decreased expression of the phosphatase and tensin homolog (PTEN) protein, leading to increased phosphorylation and activation of AKT, a component of a pro-proliferative and antiapoptotic pathway. Systemic injection of a locked nucleic acid-modified antagomir targeting miR-21 diminished the pro-proliferative impact of down-regulated PTEN, leading to a marked increase in the size of AAA. Similar results were seen in mice with AAA augmented by nicotine and in human aortic tissue samples from patients undergoing surgical repair of AAA (with more pronounced effects observed in smokers). Modulation of miR-21 expression shows potential as a new therapeutic option to limit AAA expansion and vascular disease progression.

    View details for DOI 10.1126/scitranslmed.3003441

    View details for PubMedID 22357537

  • MicroRNA-26a Is a Novel Regulator of Vascular Smooth Muscle Cell Function JOURNAL OF CELLULAR PHYSIOLOGY Leeper, N. J., Raiesdana, A., Kojima, Y., Chun, H. J., Azuma, J., Maegdefessel, L., Kundu, R. K., Quertermous, T., Tsao, P. S., Spin, J. M. 2011; 226 (4): 1035-1043

    Abstract

    Aberrant smooth muscle cell (SMC) plasticity has been implicated in a variety of vascular disorders including atherosclerosis, restenosis, and abdominal aortic aneurysm (AAA) formation. While the pathways governing this process remain unclear, epigenetic regulation by specific microRNAs (miRNAs) has been demonstrated in SMCs. We hypothesized that additional miRNAs might play an important role in determining vascular SMC phenotype. Microarray analysis of miRNAs was performed on human aortic SMCs undergoing phenotypic switching in response to serum withdrawal, and identified 31 significantly regulated entities. We chose the highly conserved candidate miRNA-26a for additional studies. Inhibition of miRNA-26a accelerated SMC differentiation, and also promoted apoptosis, while inhibiting proliferation and migration. Overexpression of miRNA-26a blunted differentiation. As a potential mechanism, we investigated whether miRNA-26a influences TGF-β-pathway signaling. Dual-luciferase reporter assays demonstrated enhanced SMAD signaling with miRNA-26a inhibition, and the opposite effect with miRNA-26a overexpression in transfected human cells. Furthermore, inhibition of miRNA-26a increased gene expression of SMAD-1 and SMAD-4, while overexpression inhibited SMAD-1. MicroRNA-26a was also found to be downregulated in two mouse models of AAA formation (2.5- to 3.8-fold decrease, P < 0.02) in which enhanced switching from contractile to synthetic phenotype occurs. In summary, miRNA-26a promotes vascular SMC proliferation while inhibiting cellular differentiation and apoptosis, and alters TGF-β pathway signaling. MicroRNA-26a represents an important new regulator of SMC biology and a potential therapeutic target in AAA disease.

    View details for DOI 10.1002/jcp.22422

    View details for Web of Science ID 000287258800019

    View details for PubMedID 20857419

    View details for PubMedCentralID PMC3108574

  • Stem Cell Therapy for Vascular Regeneration Adult, Embryonic, and Induced Pluripotent Stem Cells CIRCULATION Leeper, N. J., Hunter, A. L., Cooke, J. P. 2010; 122 (5): 517-526
  • Apelin prevents aortic aneurysm formation by inhibiting macrophage inflammation AMERICAN JOURNAL OF PHYSIOLOGY-HEART AND CIRCULATORY PHYSIOLOGY Leeper, N. J., Tedesco, M. M., Kojima, Y., Schultz, G. M., Kundu, R. K., Ashley, E. A., Tsao, P. S., Dalman, R. L., Quertermous, T. 2009; 296 (5): H1329-H1335

    Abstract

    Apelin is a potent inodilator with recently described antiatherogenic properties. We hypothesized that apelin might also attenuate abdominal aortic aneurysm (AAA) formation by limiting disease-related vascular wall inflammation. C57BL/6 mice implanted with osmotic pumps filled with apelin or saline were treated with pancreatic elastase to create infrarenal AAAs. Mice were euthanized for aortic PCR analysis or followed ultrasonographically and then euthanized for histological analysis. The cellular expression of inflammatory cytokines and chemokines in response to apelin was also assessed in cultured macrophages, smooth muscle cells, and fibroblasts. Apelin treatment resulted in diminished AAA formation, with a 47% reduction in maximal cross-sectional area (0.74 vs. 1.39 mm(2), P < 0.03) and a 57% reduction in macrophage infiltrate (113 vs. 261.3 cells/high-power field, P < 0.0001) relative to the saline-treated group. Apelin infusion was also associated with significantly reduced aortic macrophage colony-stimulating factor expression and decreased monocyte chemattractant protein (MCP)-1, macrophage inflammatory protein (MIP)-1alpha, interleukin (IL)-6, and tumor necrosis factor (TNF)-alpha mean mRNA levels. Apelin stimulation of cultured macrophages significantly reduced MCP-1 and TNF-alpha mRNA levels relative to baseline (2.03- and 1.89-fold reduction, P < 0.03, respectively) but did not affect intimal adhesion molecule expression or medial or adventitial cell cytokine production. Apelin significantly reduces aneurysm formation in the elastase model of human AAA disease. The mechanism appears to be decreased macrophage burden, perhaps related to an apelin-mediated decrease in proinflammatory cytokine and chemokine activation.

    View details for DOI 10.1152/ajpheart.01341.2008

    View details for Web of Science ID 000265659100020

    View details for PubMedID 19304942

    View details for PubMedCentralID PMC2685356

  • Clinical problem-solving. Fool's Gold. New England journal of medicine Leeper, N. J., Dhaliwal, G., Saint, S., Witteles, R. M. 2008; 359 (19): 2035-2041

    View details for DOI 10.1056/NEJMcps0802668

    View details for PubMedID 18987372

  • Statin use in patients with extremely low low-density lipoprotein levels is associated with improved survival CIRCULATION Leeper, N. J., Ardehali, R., DeGoma, E. M., Heidenreich, P. A. 2007; 116 (6): 613-618

    Abstract

    Aggressive lipid management has recently become the standard of care for patients with coronary heart disease. The safety and effectiveness of statin usage for patients with extremely low low-density lipoprotein (LDL) levels are less clear, however. The aim of this study was to investigate the safety and clinical outcomes of statin treatment in patients with LDL cholesterol levels below 60 mg/dL.A total of 6107 consecutive patients with LDL levels less than 60 mg/dL were identified from a tertiary care medical center or affiliated community clinic. Statin therapy was defined as a prescription during the 150 days after the low LDL value was obtained. The propensity to be treated with a statin was used to adjust the association of statin therapy and survival. A total of 4295 patients (70%) had at least 1 prescription for any medication during the 150-day observation period after the low LDL value. Their mean age was 65 years, 43% had prior ischemic heart disease, and 47% had diabetes mellitus. Statins were prescribed in 2564 patients (60%) after the low LDL value was observed. During a mean follow-up of 2.0+/-1.4 years after the observation period, there were 510 deaths. After controlling for the propensity to receive a statin, statin therapy was associated with improved survival (hazard ratio [HR], 0.65; 95% CI, 0.53 to 0.80). This lower mortality was also observed for subgroups of patients already taking statins at baseline (HR, 0.58; 95% CI, 0.38 to 0.88), those with extremely low LDL levels (<40 mg/dL, n=623; HR, 0.51; 95% CI, 0.33 to 0.79), and those without a history of ischemic heart disease (n=2438; HR, 0.58; 95% CI, 0.42 to 0.80). Statin use was not associated with an increase in malignancy, transaminase elevation, or rhabdomyolysis.Statin therapy in the setting of a very low LDL level appears to be safe and is associated with improved survival.

    View details for DOI 10.1161/CIRCULATIONAHA.107.694117

    View details for Web of Science ID 000248572300010

    View details for PubMedID 17664373

  • Clinical problem-solving. One surprise after another. New England journal of medicine Leeper, N. J., Wener, L. S., Dhaliwal, G., Saint, S., Wachter, R. M. 2005; 352 (14): 1474-1479

    View details for PubMedID 15814884

  • Cloning of a unique lipase from endothelial cells extends the lipase gene family JOURNAL OF BIOLOGICAL CHEMISTRY Hirata, K., Dichek, H. L., Cioffi, J. A., Choi, S. Y., Leeper, N. J., Quintana, L., Kronmal, G. S., Cooper, A. D., Quertermous, T. 1999; 274 (20): 14170-14175

    Abstract

    A new lipoprotein lipase-like gene has been cloned from endothelial cells through a subtraction methodology aimed at characterizing genes that are expressed with in vitro differentiation of this cell type. The conceptual endothelial cell-derived lipase protein contains 500 amino acids, including an 18-amino acid hydrophobic signal sequence, and is 44% identical to lipoprotein lipase and 41% identical to hepatic lipase. Comparison of primary sequence to that of lipoprotein and hepatic lipase reveals conservation of the serine, aspartic acid, and histidine catalytic residues as well as the 10 cysteine residues involved in disulfide bond formation. Expression was identified in cultured human umbilical vein endothelial cells, human coronary artery endothelial cells, and murine endothelial-like yolk sac cells by Northern blot. In addition, Northern blot and in situ hybridization analysis revealed expression of the endothelial-derived lipase in placenta, liver, lung, ovary, thyroid gland, and testis. A c-Myc-tagged protein secreted from transfected COS7 cells had phospholipase A1 activity but no triglyceride lipase activity. Its tissue-restricted pattern of expression and its ability to be expressed by endothelial cells, suggests that endothelial cell-derived lipase may have unique functions in lipoprotein metabolism and in vascular disease.

    View details for Web of Science ID 000080322200064

    View details for PubMedID 10318835

  • Single-nucleus chromatin accessibility profiling highlights regulatory mechanisms of coronary artery disease risk. Nature genetics Turner, A. W., Hu, S. S., Mosquera, J. V., Ma, W. F., Hodonsky, C. J., Wong, D., Auguste, G., Song, Y., Sol-Church, K., Farber, E., Kundu, S., Kundaje, A., Lopez, N. G., Ma, L., Ghosh, S. K., Onengut-Gumuscu, S., Ashley, E. A., Quertermous, T., Finn, A. V., Leeper, N. J., Kovacic, J. C., Björkgren, J. L., Zang, C., Miller, C. L. 2022

    Abstract

    Coronary artery disease (CAD) is a complex inflammatory disease involving genetic influences across cell types. Genome-wide association studies have identified over 200 loci associated with CAD, where the majority of risk variants reside in noncoding DNA sequences impacting cis-regulatory elements. Here, we applied single-nucleus assay for transposase-accessible chromatin with sequencing to profile 28,316 nuclei across coronary artery segments from 41 patients with varying stages of CAD, which revealed 14 distinct cellular clusters. We mapped ~320,000 accessible sites across all cells, identified cell-type-specific elements and transcription factors, and prioritized functional CAD risk variants. We identified elements in smooth muscle cell transition states (for example, fibromyocytes) and functional variants predicted to alter smooth muscle cell- and macrophage-specific regulation of MRAS (3q22) and LIPA (10q23), respectively. We further nominated key driver transcription factors such as PRDM16 and TBX2. Together, this single-nucleus atlas provides a critical step towards interpreting regulatory mechanisms across the continuum of CAD risk.

    View details for DOI 10.1038/s41588-022-01069-0

    View details for PubMedID 35590109

  • 2021 Jeffrey M. Hoeg Award Lecture: Defining the Role of Efferocytosis in Cardiovascular Disease: A Focus on the CD47 (Cluster of Differentiation 47) Axis. Arteriosclerosis, thrombosis, and vascular biology Jarr, K., Kojima, Y., Weissman, I. L., Leeper, N. J. 2022: 101161ATVBAHA122317049

    Abstract

    A key feature of atherogenesis is the accumulation of diseased and dying cells within the lesional necrotic core. While the burden of intraplaque apoptotic cells may be driven in part by an increase in programmed cell death, mounting evidence suggests that their presence may primarily be dictated by a defect in programmed cell removal, or efferocytosis. In this brief review, we will summarize the evidence suggesting that inflammation-dependent changes within the plaque render target cells inedible and reduce the appetite of lesional phagocytes. We will present the genetic causation studies, which indicate these phenomena promote lesion expansion and plaque vulnerability, and the interventional data which suggest that these processes can be reversed. Particular emphasis is provided related to the antiphagocytic CD47 (cluster of differentiation 47) do not eat me axis, which has emerged as a novel antiatherosclerotic translational target that is predicted to provide benefit independent of traditional cardiovascular risk factors.

    View details for DOI 10.1161/ATVBAHA.122.317049

    View details for PubMedID 35387480

  • Plaque Evaluation by Ultrasound and Transcriptomics Reveals BCLAF1 as a Regulator of Smooth Muscle Cell Lipid Transdifferentiation in Atherosclerosis. Arteriosclerosis, thrombosis, and vascular biology Rykaczewska, U., Zhao, Q., Saliba-Gustafsson, P., Lengquist, M., Kronqvist, M., Bergman, O., Huang, Z., Lund, K., Waden, K., Pons, V. Z., Caidahl, K., Skogsberg, J., Vukojevic, V., Lindeman, J. H., Roy, J., Hansson, G. K., Treuter, E., Leeper, N. J., Eriksson, P., Ehrenborg, E., Razuvaev, A., Hedin, U., Matic, L. 2022: ATVBAHA121317018

    Abstract

    BACKGROUND: Understanding the processes behind carotid plaque instability is necessary to develop methods for identification of patients and lesions with stroke risk. Here, we investigated molecular signatures in human plaques stratified by echogenicity as assessed by duplex ultrasound.METHODS: Lesion echogenicity was correlated to microarray gene expression profiles from carotid endarterectomies (n=96). The findings were extended into studies of human and mouse atherosclerotic lesions in situ, followed by functional investigations in vitro in human carotid smooth muscle cells (SMCs).RESULTS: Pathway analyses highlighted muscle differentiation, iron homeostasis, calcification, matrix organization, cell survival balance, and BCLAF1 (BCL2 [B-cell lymphoma 2]-associated transcription factor 1) as the most significant signatures. BCLAF1 was downregulated in echolucent plaques, positively correlated to proliferation and negatively to apoptosis. By immunohistochemistry, BCLAF1 was found in normal medial SMCs. It was repressed early during atherogenesis but reappeared in CD68+ cells in advanced plaques and interacted with BCL2 by proximity ligation assay. In cultured SMCs, BCLAF1 was induced by differentiation factors and mitogens and suppressed by macrophage-conditioned medium. BCLAF1 silencing led to downregulation of BCL2 and SMC markers, reduced proliferation, and increased apoptosis. Transdifferentiation of SMCs by oxLDL was accompanied by upregulation of BCLAF1, CD36, and CD68, while oxLDL exposure with BCLAF1 silencing preserved MYH (myosin heavy chain) 11 expression and prevented transdifferentiation. BCLAF1 was associated with expression of cell differentiation, contractility, viability, and inflammatory genes, as well as the scavenger receptors CD36 and CD68. BCLAF1 expression in CD68+/BCL2+ cells of SMC origin was verified in plaques from MYH11 lineage-tracing atherosclerotic mice. Moreover, BCLAF1 downregulation associated with vulnerability parameters and cardiovascular risk in patients with carotid atherosclerosis.CONCLUSIONS: Plaque echogenicity correlated with enrichment of distinct molecular pathways and identified BCLAF1, previously not described in atherosclerosis, as the most significant gene. Functionally, BCLAF1 seems necessary for survival and transdifferentiation of SMCs into a macrophage-like phenotype. The role of BCLAF1 in plaque vulnerability should be further evaluated.

    View details for DOI 10.1161/ATVBAHA.121.317018

    View details for PubMedID 35321563

  • Development of a polygenic risk score to improve detection of peripheral artery disease. Vascular medicine (London, England) Wang, F., Ghanzouri, I., Leeper, N. J., Tsao, P. S., Ross, E. G. 2022: 1358863X211067564

    Abstract

    INTRODUCTION: Peripheral artery disease (PAD) is a major cause of cardiovascular morbidity and mortality, yet timely diagnosis is elusive. Larger genome-wide association studies (GWAS) have now provided the ability to evaluate whether genetic data, in the form of genome-wide polygenic risk scores (PRS), can help improve our ability to identify patients at high risk of having PAD.METHODS: Using summary statistic data from the largest PAD GWAS from the Million Veteran Program, we developed PRSs with genome data from UK Biobank. We then evaluated the clinical utility of adding the best-performing PRS to a PAD clinical risk score.RESULTS: A total of 487,320 participants (5759 PAD cases) were included in our final genetic analysis. Compared to participants in the lowest 10% of PRS, those in the highest decile had 3.1 higher odds of having PAD (95% CI, 3.06-3.21). Additionally, a PAD PRS was associated with increased risk of having coronary artery disease, congestive heart failure, and cerebrovascular disease. The PRS significantly improved a clinical risk model (Net Reclassification Index = 0.07, p < 0.001), with most of the performance seen in downgrading risk of controls. Combining clinical and genetic data to detect risk of PAD resulted in a model with an area under the curve of 0.76 (95% CI, 0.75-0.77).CONCLUSION: We demonstrate that a genome-wide PRS can discriminate risk of PAD and other cardiovascular diseases. Adding a PAD PRS to clinical risk models may help improve detection of prevalent, but undiagnosed disease.

    View details for DOI 10.1177/1358863X211067564

    View details for PubMedID 35287516

  • Prevention of arterial and venous thrombotic events in symptomatic peripheral arterial disease patients after lower extremity revascularization in the VOYAGER PAD trial: Dual anticoagulant/antiplatelet regimen vs antiplatelet therapy alone. Journal of thrombosis and haemostasis : JTH Berkowitz, S. D., Bauersachs, R. M., Szarek, M., Nehler, M. R., Debus, E. S., Patel, M. R., Anand, S. S., Capell, W. H., Hess, C. N., Hsia, J., Leeper, N. J., Brasil, D., Mátyás, L., Diaz, R., Brodmann, M., Muehlhofer, E., Haskell, L., Bonaca, M. P. 2022

    Abstract

    Vascular disease burden after lower extremity revascularization (LER) comprises more than the first event, more vascular beds than the local arteries, and more than one clinical event type.Assess total arterial and venous thrombotic burden after LER for symptomatic peripheral artery disease (PAD) and effect of low-dose anticoagulation added to low-dose antiplatelet therapy.VOYAGER PAD randomized 6,564 symptomatic PAD patients undergoing LER to rivaroxaban 2.5 mg twice-daily or placebo on aspirin background. Marginal proportional-hazards models used to generate treatment hazard ratios and associated 95% CIs for first and total events; non-thrombotic deaths treated as competing terminal events. Incidence rates calculated as number of events per 100 patient-years follow-up.Over 2.5 years (median), first and total thrombotic event rates: 7.1 and 10.3 events/100 patient-years, respectively, in placebo group. Two-thirds (925/1,372) of total thrombotic events (arterial 95%, venous 5%) were nonfatal first events. Nearly 1/3 of patients with first event had a second arterial or venous thrombotic event. Rivaroxaban plus aspirin reduced first and total arterial and venous thrombotic events to 5.4 and 7.9 events/100 patient-years, respectively, a reduction in total thrombotic events over aspirin of 23% (HR 0.77, 95%CI 0.67-0.89, p=0.0005), preventing 6.1 total arterial and venous thrombotic events at 3 years.Assessing total arterial and venous thrombotic events, not just first events, provides more complete information about disease burden and absolute on-treatment impact. Following LER, judicious modulation of more than one coagulation pathway can provide broader benefit than intensifying inhibition of one hemostatic system component.

    View details for DOI 10.1111/jth.15673

    View details for PubMedID 35170216

  • Unsupervised Learning for Automated Detection of Coronary Artery Disease Subgroups. Journal of the American Heart Association Flores, A. M., Schuler, A., Eberhard, A. V., Olin, J. W., Cooke, J. P., Leeper, N. J., Shah, N. H., Ross, E. G. 2021: e021976

    Abstract

    Background The promise of precision population health includes the ability to use robust patient data to tailor prevention and care to specific groups. Advanced analytics may allow for automated detection of clinically informative subgroups that account for clinical, genetic, and environmental variability. This study sought to evaluate whether unsupervised machine learning approaches could interpret heterogeneous and missing clinical data to discover clinically important coronary artery disease subgroups. Methods and Results The Genetic Determinants of Peripheral Arterial Disease study is a prospective cohort that includes individuals with newly diagnosed and/or symptomatic coronary artery disease. We applied generalized low rank modeling and K-means cluster analysis using 155 phenotypic and genetic variables from 1329 participants. Cox proportional hazard models were used to examine associations between clusters and major adverse cardiovascular and cerebrovascular events and all-cause mortality. We then compared performance of risk stratification based on clusters and the American College of Cardiology/American Heart Association pooled cohort equations. Unsupervised analysis identified 4 phenotypically and prognostically distinct clusters. All-cause mortality was highest in cluster 1 (oldest/most comorbid; 26%), whereas major adverse cardiovascular and cerebrovascular event rates were highest in cluster 2 (youngest/multiethnic; 41%). Cluster 4 (middle-aged/healthiest behaviors) experienced more incident major adverse cardiovascular and cerebrovascular events (30%) than cluster 3 (middle-aged/lowest medication adherence; 23%), despite apparently similar risk factor and lifestyle profiles. In comparison with the pooled cohort equations, cluster membership was more informative for risk assessment of myocardial infarction, stroke, and mortality. Conclusions Unsupervised clustering identified 4 unique coronary artery disease subgroups with distinct clinical trajectories. Flexible unsupervised machine learning algorithms offer the ability to meaningfully process heterogeneous patient data and provide sharper insights into disease characterization and risk assessment. Registration URL: https://www.clinicaltrials.gov; Unique identifier: NCT00380185.

    View details for DOI 10.1161/JAHA.121.021976

    View details for PubMedID 34845917

  • Dynamic changes in chromatin accessibility are associated with the atherogenic transitioning of vascular smooth muscle cells. Cardiovascular research Wang, Y., Gao, H., Wang, F., Ye, Z., Mokry, M., Turner, A. W., Ye, J., Koplev, S., Luo, L., Alsaigh, T., Adkar, S. S., Elishaev, M., Gao, X., Maegdefessel, L., Bjorkegren, J. L., Pasterkamp, G., Miller, C. L., Ross, E. G., Leeper, N. J. 2021

    Abstract

    AIMS: De-differentiation and activation of pro-inflammatory pathways are key transitions vascular smooth muscle cells (SMCs) make during atherogenesis. Here, we explored the upstream regulators of this 'atherogenic transition'.METHODS AND RESULTS: Genome-wide sequencing studies, including ATAC-seq (Assay for Transposase-Accessible Chromatin using sequencing) and RNA-seq, were performed on cells isolated from both murine SMC-lineage tracing models of atherosclerosis and human atherosclerotic lesions. At the bulk level, alterations in chromatin accessibility were associated with the atherogenic transitioning of lesional SMCs, especially in relation to genes that govern differentiation status and complement-dependent inflammation. Using computational biology, we observed that a transcription factor previously related to coronary artery disease, ATF3 (Activating transcription factor 3), was predicted to be an upstream regulator of genes altered during the transition. At the single-cell level, our results indicated that ATF3 is a key repressor of SMC transitioning towards the subset of cells that promote vascular inflammation by activating the complement cascade. The expression of ATF3 and complement component C3 were negatively correlated in SMCs from human atherosclerotic lesions, suggesting translational relevance. Phenome-wide association studies indicated that genetic variation that results in reduced expression of ATF3 is correlated with an increased risk for atherosclerosis, and the expression of ATF3 was significantly downregulated in humans with advanced vascular disease.CONCLUSION: Our study indicates that the plasticity of atherosclerotic SMCs may in part be explained by dynamic changes in their chromatin architecture, which in turn may contribute to their maladaptive response to inflammation-induced stress.TRANSLATIONAL PERSPECTIVE: The recent CANTOS and COLCOT trials have shown that targeting inflammatory pathways lowers the risk of major adverse cardiovascular events. However, more specific targets are needed to avoid immunosuppressive side effects. Our data identify an upstream regulator of pro-inflammatory SMCs, ATF3, which is involved in the initial atherogenic transitioning of lesional SMCs. Restoring ATF3 activity may prevent the de-differentiation of SMCs and offer a novel translational approach for the suppression of complement-dependent inflammation in atherosclerotic lesions.

    View details for DOI 10.1093/cvr/cvab347

    View details for PubMedID 34849613

  • Macrophage LRP1 (Low-Density Lipoprotein Receptor-Related Protein 1) Is Required for the Effect of CD47 Blockade on Efferocytosis and Atherogenesis. Arteriosclerosis, thrombosis, and vascular biology Mueller, P. A., Kojima, Y., Huynh, K. T., Maldonado, R. A., Ye, J., Tavori, H., Pamir, N., Leeper, N. J., Fazio, S. 2021: ATVBAHA121316854

    Abstract

    OBJECTIVE: Antibody blockade of the do not eat me signal CD47 enhances efferocytosis and reduces lesion size and necrotic core formation in murine atherosclerosis. TNF (Tumor necrosis factor)-alpha expression directly enhances CD47 expression, and elevated TNF-alpha is observed in the absence of the proefferocytosis receptor LRP1 (low-density lipoprotein receptor-related protein 1), a regulator of atherogenesis and inflammation. Thus, we tested the hypothesis that CD47 blockade requires the presence of macrophage LRP1 to enhance efferocytosis, temper TNF-alpha-dependent inflammation, and limit atherosclerosis. Approach and Results: Mice lacking systemic apoE (apoE-/-), alone or in combination with the loss of macrophage LRP1 (double knockout), were fed a Western-type diet for 12 weeks while receiving anti-CD47 antibody (anti-CD47) or IgG every other day. In apoE-/- mice, treatment with anti-CD47 reduced lesion size by 25.4%, decreased necrotic core area by 34.5%, and decreased the ratio of free:macrophage-associated apoptotic bodies by 47.6% compared with IgG controls (P<0.05), confirming previous reports. Double knockout mice treated with anti-CD47 showed no differences in lesion size, necrotic core area, or the ratio of free:macrophage-associated apoptotic bodies compared with IgG controls. In vitro efferocytosis was 30% higher when apoE-/- phagocytes were incubated with anti-CD47 compared with IgG controls (P<0.05); however, anti-CD47 had no effect on efferocytosis in double knockout phagocytes. Analyses of mRNA and protein showed increased CD47 expression in anti-inflammatory IL (interleukin)-4 treated LRP1-/- macrophages compared with wild type, but no differences were observed in inflammatory lipopolysaccharide-treated macrophages.CONCLUSIONS: The proefferocytosis receptor LRP1 in macrophages is necessary for anti-CD47 blockade to enhance efferocytosis, limit atherogenesis, and decrease necrotic core formation in the apoE-/- model of atherosclerosis.

    View details for DOI 10.1161/ATVBAHA.121.316854

    View details for PubMedID 34758632

  • Ultra-selective carbon nanotubes for photoacoustic imaging of inflamed atherosclerotic plaques. Advanced functional materials Gifani, M., Eddins, D. J., Kosuge, H., Zhang, Y., Paluri, S. L., Larson, T., Leeper, N., Herzenberg, L. A., Gambhir, S. S., McConnell, M. V., Ghosn, E. E., Smith, B. R. 2021; 31 (37)

    Abstract

    Disruption of vulnerable atherosclerotic plaques often leads to myocardial infarction and stroke, the leading causes of morbidity and mortality in the United States. A diagnostic method that detects high-risk atherosclerotic plaques at early stages could prevent these sequelae. The abundance of immune cells in the arterial wall, especially inflammatory Ly-6Chi monocytes and foamy macrophages, is indicative of plaque‎ inflammation, and may be associated with plaque vulnerability. Hence, we sought to develop a new method that specifically targets these immune cells to offer clinically-relevant diagnostic information about cardiovascular disease. We combine ultra-selective nanoparticle targeting of Ly-6Chi monocytes and foamy macrophages with clinically-viable photoacoustic imaging (PAI) in order to precisely and specifically image inflamed plaques ex vivo in a mouse model that mimics human vulnerable plaques histopathologically. Within the plaques, high-dimensional single-cell flow cytometry (13-parameter) showed that our nanoparticles were almost-exclusively taken up by the Ly-6Chi monocytes and foamy macrophages that heavily infiltrate plaques. PAI identified inflamed atherosclerotic plaques that display ~6-fold greater signal compared to controls (P<0.001) six hours after intravenous injection of ultra-selective carbon nanotubes, with in vivo corroboration via optical imaging. Our highly selective strategy may provide a targeted, non-invasive imaging strategy to accurately identify and diagnose inflamed atherosclerotic lesions.

    View details for DOI 10.1002/adfm.202101005

    View details for PubMedID 34733130

    View details for PubMedCentralID PMC8559995

  • Ultraselective Carbon Nanotubes for Photoacoustic Imaging of Inflamed Atherosclerotic Plaques ADVANCED FUNCTIONAL MATERIALS Gifani, M., Eddins, D. J., Kosuge, H., Zhang, Y., Paluri, S. A., Larson, T., Leeper, N., Herzenberg, L. A., Gambhir, S., McConnell, M., Ghosn, E. B., Smith, B. 2021
  • Peripheral Vascular Disease in 2021. Circulation research Leeper, N. J., Hamburg, N. M. 2021; 128 (12): 1803-1804

    View details for DOI 10.1161/CIRCRESAHA.121.319562

    View details for PubMedID 34110903

  • Leveraging Machine Learning and Artificial Intelligence to Improve Peripheral Artery Disease Detection, Treatment, and Outcomes. Circulation research Flores, A. M., Demsas, F., Leeper, N. J., Ross, E. G. 2021; 128 (12): 1833-1850

    Abstract

    Peripheral artery disease is an atherosclerotic disorder which, when present, portends poor patient outcomes. Low diagnosis rates perpetuate poor management, leading to limb loss and excess rates of cardiovascular morbidity and death. Machine learning algorithms and artificially intelligent systems have shown great promise in application to many areas in health care, such as accurately detecting disease, predicting patient outcomes, and automating image interpretation. Although the application of these technologies to peripheral artery disease are in their infancy, their promises are tremendous. In this review, we provide an introduction to important concepts in the fields of machine learning and artificial intelligence, detail the current state of how these technologies have been applied to peripheral artery disease, and discuss potential areas for future care enhancement with advanced analytics.

    View details for DOI 10.1161/CIRCRESAHA.121.318224

    View details for PubMedID 34110911

  • Comparison of Pre-Amputation Evaluation in Patients with and without Chronic Kidney Disease. American journal of nephrology Subramanian, N., Han, J., Leeper, N. J., Ross, E. G., Montez-Rath, M. E., Chang, T. I. 2021: 1–8

    Abstract

    INTRODUCTION: Patients with chronic kidney disease (CKD) and peripheral artery disease (PAD) are more likely to undergo lower extremity amputation than patients with preserved kidney function. We sought to determine whether patients with CKD were less likely to receive pre-amputation care in the 1-year prior to lower extremity amputation compared to patients without CKD.METHODS: We conducted a retrospective observational study of patients with PAD-related lower extremity amputation between January 2014 and December 2017 using a large commercial insurance database. The primary exposure was CKD identified using billing codes and laboratory values. The primary outcomes were receipt of pre-amputation care, defined as diagnostic evaluation (ankle-brachial index, duplex ultrasound, and computed tomographic angiography), specialty care (vascular surgery, cardiology, orthopedic surgery, and podiatry), and lower extremity revascularization in the 1-year prior to amputation. We conducted separate logistic regression models to estimate the adjusted odds ratio (aOR) and 95% confidence intervals (CIs) among patients with and without CKD. We assessed for effect modification by age, sex, Black race, and diabetes status.RESULTS: We identified 8,554 patients with PAD-related amputation. In fully adjusted models, patients with CKD were more likely to receive diagnostic evaluation (aOR 1.30; 95% CI 1.17-1.44) and specialty care (aOR 1.45, 95% CI 1.27-1.64) in the 1-year prior to amputation. There was no difference in odds of revascularization by CKD status (aOR 1.03, 0.90-1.19). Age, sex, Black race, and diabetes status did not modify these associations.DISCUSSION/CONCLUSION: Patients with CKD had higher odds of receiving diagnostic testing and specialty care and similar odds of lower extremity revascularization in the 1-year prior to amputation than patients without CKD. Disparities in access to pre-amputation care do not appear to explain the higher amputation rates seen among patients with CKD.

    View details for DOI 10.1159/000516017

    View details for PubMedID 33957619

  • US National Trends in Vascular Surgical Practice During the COVID-19 Pandemic. JAMA surgery Ho, V. T., Eberhard, A. V., Asch, S. M., Leeper, N. J., Fukaya, E., Arya, S., Ross, E. G. 2021

    View details for DOI 10.1001/jamasurg.2021.1708

    View details for PubMedID 33856428

  • 2021 ACC/AHA/SVM/ACP Advanced Training Statement on Vascular Medicine (Revision of the 2004 ACC/ACP/SCAI/SVMB/SVS Clinical Competence Statement on Vascular Medicine and Catheter-Based Peripheral Vascular Interventions) JOURNAL OF THE AMERICAN COLLEGE OF CARDIOLOGY Creager, M. A., Hamburg, N. M., Calligaro, K. D., Casanegra, A., Freeman, R., Gordon, P. A., Gornik, H. L., Kim, E. H., Leeper, N. J., Merli, G. J., Niazi, K., Olin, J. W., Quiroz, R., Kaso, E., Wasan, S., Waxler, A. R., White, C. J., Solaru, K., Williams, M. S., ACC Competency Management Comm 2021; 77 (7): 998–1020
  • 2021 ACC/AHA/SVM/ACP Advanced Training Statement on Vascular Medicine (Revision of the 2004 ACC/ACP/SCAI/SVMB/SVS Clinical Competence Statement on Vascular Medicine and Catheter-Based Peripheral Vascular Interventions) A Report of the ACC Competency Management Committee CIRCULATION-CARDIOVASCULAR INTERVENTIONS Creager, M. A., Hamburg, N. M., Calligaro, K. D., Casanegra, A., Freeman, R., Gordon, P. A., Gornik, H. L., Kim, E. H., Leeper, N. J., Merli, G. J., Niazi, K., Olin, J. W., Quiroz, R., Kaso, E., Wasan, S., Waxler, A. R., White, C. J., Solaru, K., Williams, M. S. 2021; 14 (2): e000079

    View details for DOI 10.1161/HCV.0000000000000079

    View details for Web of Science ID 000639305500001

    View details for PubMedID 33448231

  • 2021 ACC/AHA/SVM/ACP Advanced Training Statement on Vascular Medicine (Revision of the 2004 ACC/ACP/SCAI/SVMB/SVS Clinical Competence Statement on Vascular Medicine and Catheter-Based Peripheral Vascular Interventions) VASCULAR MEDICINE Creager, M. A., Hamburg, N. M., Calligaro, K. D., Casanegra, A., Freeman, R., Gordon, P. A., Gornik, H. L., Kim, E. H., Leeper, N. J., Merli, G. J., Niazi, K., Olin, J. W., Quiroz, R., Kaso, E., Wasan, S., Waxler, A. R., White, C. J., Solaru, K., Williams, M. S., Arrighi, J. A., Mendes, L. A., Day, J., Dec, G., Denktas, A., Drajpuch, D., Fernandes, S., Francis, S. A., Hahn, R. T., Housholder-Hughes, S. D., Khan, S. S., Klarich, K., Kondapaneni, M., Lee, K. S., Lin, C., Marine, J. E., McConnaughey, S., Ryan, T., Silvestry, F. E., Solomon, M. A., Spicer, R. L., Wang, A., Weissman, G., Weitz, H. H., ACC Competency Management Comm, Assoc Black Cardiologists, Soc Cardiovasc Angiography Interve, Soc Vasc Nursing, Soc Vasc Surg 2021: 91–112

    View details for DOI 10.1177/1358863X20987551

    View details for Web of Science ID 000618412700001

    View details for PubMedID 33448240

  • Chitinase 3 like 1 (CHI3L1) is a regulator of smooth muscle cell physiology and atherosclerotic lesion stability. Cardiovascular research Tsantilas, P. n., Lao, S. n., Wu, Z. n., Eberhard, A. n., Winski, G. n., Vaerst, M. n., Nanda, V. n., Wang, Y. n., Kojima, Y. n., Ye, J. n., Flores, A. n., Jarr, K. U., Pelisek, J. n., Eckstein, H. H., Matic, L. n., Hedin, U. n., Tsao, P. S., Paloschi, V. n., Maegdefessel, L. n., Leeper, N. J. 2021

    Abstract

    Atherosclerotic cerebrovascular disease underlies the majority of ischemic strokes and is a major cause of death and disability. While plaque burden is a predictor of adverse outcomes, plaque vulnerability is increasingly recognized as a driver of lesion rupture and risk for clinical events. Defining the molecular regulators of carotid instability could inform the development of new biomarkers and/or translational targets for at-risk individuals.Using two independent human endarterectomy biobanks, we found that the understudied glycoprotein, Chitinase 3 like 1 (CHI3L1), is upregulated in patients with carotid disease compared to healthy controls. Further, CHI3L1 levels were found to stratify individuals based on symptomatology and histopathological evidence of an unstable fibrous cap. Gain- and loss-of-function studies in cultured human carotid artery smooth muscle cells (SMCs) showed that CHI3L1 prevents a number of maladaptive changes in that cell type, including phenotype switching towards a synthetic and hyperproliferative state. Using two murine models of carotid remodelling and lesion vulnerability, we found that knockdown of Chil1 resulted in larger neointimal lesions comprised by de-differentiated SMCs that failed to invest within and stabilize the fibrous cap. Exploratory mechanistic studies identified alterations in potential downstream regulatory genes, including large tumor suppressor kinase 2 (LATS2), which mediates macrophage marker and inflammatory cytokine expression on SMCs, and may explain how CHI3L1 modulates cellular plasticity.CHI3L1 is upregulated in humans with carotid artery disease and appears to be a strong mediator of plaque vulnerability. Mechanistic studies suggest this change may be a context-dependent adaptive response meant to maintain vascular SMCs in a differentiated state and to prevent rupture of the fibrous cap. Part of this effect may be mediated through downstream suppression of LATS2. Future studies should determine how these changes occur at the molecular level, and whether this gene can be targeted as a novel translational therapy for subjects at risk of stroke.Taken together, CHI3L1 has the potential to become a new translational target for cardiovascular disease. With further studies to understand its full causal relationship to inflammatory pathways, it could have a role in the diagnosis and management of patients with cerebrovascular disease at risk for stroke.

    View details for DOI 10.1093/cvr/cvab014

    View details for PubMedID 33471078

  • Reduction in Acute Limb Ischemia with Rivaroxaban versus Placebo in Peripheral Artery Disease after Lower Extremity Revascularization: Insights from VOYAGER PAD. Circulation Hess, C. N., Debus, E. S., Nehler, M. R., Anand, S. S., Patel, M. R., Szarek, M., Capell, W. H., Hsia, J., Beckman, J. A., Brodmann, M., Diaz, R., Habertheuer, P., Leeper, N. J., Powell, R. J., Sillesen, H., Muehlhofer, E., Berkowitz, S. D., Haskell, L. P., Bauersachs, R. M., Bonaca, M. P. 2021

    Abstract

    Background: Patients with peripheral artery disease (PAD) are at heightened risk of acute limb ischemia (ALI), a thrombotic event associated with amputation, disability, and mortality. Prior lower extremity revascularization (LER) is associated with increased ALI risk in chronic PAD. However, the pattern of risk, clinical correlates, and outcomes after ALI early after LER are not well-studied, and effective therapies to reduce ALI post-LER are lacking. Methods: VOYAGER PAD (NCT02504216) randomized patients with PAD undergoing LER to rivaroxaban 2.5 mg twice daily or placebo on a background of low-dose aspirin. The primary outcome was a composite of ALI, major amputation of vascular cause, myocardial infarction, ischemic stroke, or cardiovascular death. ALI was prospectively ascertained and adjudicated by a blinded committee. The cumulative incidence of ALI was calculated using Kaplan Meier estimates, and Cox proportional-hazards models were used to generate hazard ratios and associated confidence intervals. Analyses were performed as intention-to-treat. Results: Among 6,564 patients followed for a median of 2.3 years, 382 (5.8%) had a total of 508 ALI events. In placebo patients, the 3-year cumulative incidence of ALI was 7.8%. After multivariable modeling, prior LER, baseline ABI <0.50, surgical LER, and longer target lesion length were associated with increased risk of ALI. Incident ALI was associated with subsequent all-cause mortality (HR 2.59, 95% CI 1.98-3.39) and major amputation (HR 24.87, 95% CI 18.68-33.12). Rivaroxaban reduced ALI relative to placebo by 33% (absolute risk reduction 2.6% at 3 years, HR 0.67, 95% CI 0.55-0.82, P=0.0001), with benefit starting early (HR 0.45, 95% CI 0.24-0.85, P=0.0068 at 30 days). Benefit was present for severe ALI (associated with death, amputation, or prolonged hospitalization and ICU stay, HR 0.58, 95% CI 0.40-0.83, P=0.003) and regardless of LER type (surgical vs endovascular revascularization, p-interaction=0.42) or clopidogrel use (p-interaction=0.59). Conclusions: After LER for symptomatic PAD, ALI is frequent, particularly early after LER, and is associated with poor prognosis. Low-dose rivaroxaban plus aspirin reduces ALI after LER, including ALI events associated with the most severe outcomes. The benefit of rivaroxaban for ALI appears early, continues over time, and is consistent regardless of revascularization approach or clopidogrel use.

    View details for DOI 10.1161/CIRCULATIONAHA.121.055146

    View details for PubMedID 34637332

  • Intradialytic Hypotension and Newly Recognized Peripheral Artery Disease in Patients Receiving Hemodialysis. American journal of kidney diseases : the official journal of the National Kidney Foundation Seong, E. Y., Liu, S., Song, S. H., Leeper, N. J., Winkelmayer, W. C., Montez-Rath, M. E., Chang, T. I. 2020

    Abstract

    RATIONALE & OBJECTIVE: Intradialytic hypotension (IDH) may decrease systemic circulation to the legs, exacerbating symptoms of peripheral artery disease (PAD). We sought to evaluate the relationship between IDH and newly recognized lower extremity PAD among hemodialysis patients STUDY DESIGN: Retrospective cohort study.SETTING & PARTICIPANTS: Linking the data from USRDS to the electronic health records of a large dialysis provider, we identified adults patients (≥18 years) with Medicare Parts A and B who initiated dialysis (2006-2011) without previously recognized PAD.EXPOSURE: Time-varying proportion of hemodialysis sessions with IDH defined as nadir intradialytic systolic blood pressure <90 mmHg. We categorized the proportion of sessions with IDH within serial 30-day intervals as 0%, >0-<15%, 15-<30%, and ≥30%.OUTCOME: Newly recognized PAD, ascertained using PAD diagnosis codes and procedure codes for amputation or revascularization, in serial 30-day intervals subsequent to each 30-day exposure interval.ANALYTIC APPROACH: To account for the competing risks of death and kidney transplantation, we estimated unadjusted and adjusted sub-distribution hazard ratios using the Kaplan-Meier multiple imputation method in combination with the extended Cox model to account for IDH as a time-varying exposure.RESULTS: Among 45,591 patients, those with more frequent baseline IDH had a higher prevalence of cardiovascular diseases. During 61,725 person-years of follow-up, 7,886 patients had newly recognized PAD. We found a graded, direct association of IDH with newly recognized PAD. For example, having IDH in ≥30% of dialysis sessions during a given 30-day interval (versus 0%) was associated with a 24% higher hazard of having newly recognized PAD (95% CI, 17% to 32%) in the subsequent 30 days.LIMITATIONS: Unmeasured confounding; ascertainment of PAD from claims CONCLUSIONS: Patients receiving hemodialysis who had more frequent IDH had higher rates of newly recognized PAD. Patients with frequent IDH may warrant careful examination for PAD.

    View details for DOI 10.1053/j.ajkd.2020.10.012

    View details for PubMedID 33316351

  • Macrophage-targeted single walled carbon nanotubes stimulate phagocytosis via pH-dependent drug release NANO RESEARCH Zhang, Y., Ye, J., Hosseini-Nassab, N., Flores, A., Kalashnikova, I., Paluri, S., Lotfi, M., Leeper, N. J., Smith, B. 2020
  • Incentivizing physical activity through activity monitoring interventions in PAD - a pilot study. VASA. Zeitschrift fur Gefasskrankheiten Fukaya, E., Welden, S., Bukari, A., Khan, Z., Leeper, N., Mohler, E. 2020: 1–6

    Abstract

    Background: There is ample evidence to show that supervised exercise is efficacious and cost effective for improving claudication symptoms in patients with peripheral artery disease (PAD). Home based exercise therapy can be an effective alternative to supervised exercise however, the results of this is variable depending on the level of motivation and engagement of the patient. Patients and methods: We performed a pilot study in 41 patients to determine whether a home based exercise program with the use of an activity tracking device with personalized feedback and financial incentives can increase daily activity, improve walking and sustain engagement in the exercise regimen in patients with PAD. In this randomized pilot study, the patients in the study group were fitted with an activity monitoring device and given behavioral monitoring, motivational updates and feedback regarding their exercise program. This study group was further divided in to two groups. One half of these patients in the study group were also given financial incentives if they reached their set targets. The control group wore the device with no feedback or ability to see their number of steps walked. Results: Results showed that at the end of the 12 week period, patients in the study groups walked more compared to the controls and the financial incentive structure resulted in an additional 38-63% increase in average daily steps. Conclusions: This pilot study revealed that a home-based exercise program with activity monitoring, feedback and financial incentives resulted increased daily steps, 6-minute walking distance and overall compliance with the program in PAD patients with claudication.

    View details for DOI 10.1024/0301-1526/a000924

    View details for PubMedID 33150850

  • 18F-Fluorodeoxyglucose-Positron Emission Tomography Imaging Detects Response to Therapeutic Intervention and Plaque Vulnerability in a Murine Model of Advanced Atherosclerotic Disease. Arteriosclerosis, thrombosis, and vascular biology Jarr, K., Ye, J., Kojima, Y., Nanda, V., Flores, A. M., Tsantilas, P., Wang, Y., Hosseini-Nassab, N., Eberhard, A. V., Lotfi, M., Kaller, M., Smith, B. R., Maegdefessel, L., Leeper, N. J. 2020: ATVBAHA120315239

    Abstract

    OBJECTIVE: This study sought to determine whether 18F-fluorodeoxyglucose-positron emission tomography/computed tomography could be applied to a murine model of advanced atherosclerotic plaque vulnerability to detect response to therapeutic intervention and changes in lesion stability. Approach and Results: To analyze plaques susceptible to rupture, we fed ApoE-/- mice a high-fat diet and induced vulnerable lesions by cast placement over the carotid artery. After 9 weeks of treatment with orthogonal therapeutic agents (including lipid-lowering and proefferocytic therapies), we assessed vascular inflammation and several features of plaque vulnerability by 18F-fluorodeoxyglucose-positron emission tomography/computed tomography and histopathology, respectively. We observed that 18F-fluorodeoxyglucose-positron emission tomography/computed tomography had the capacity to resolve histopathologically proven changes in plaque stability after treatment. Moreover, mean target-to-background ratios correlated with multiple characteristics of lesion instability, including the corrected vulnerability index.CONCLUSIONS: These results suggest that the application of noninvasive 18F-fluorodeoxyglucose-positron emission tomography/computed tomography to a murine model can allow for the identification of vulnerable atherosclerotic plaques and their response to therapeutic intervention. This approach may prove useful as a drug discovery and prioritization method.

    View details for DOI 10.1161/ATVBAHA.120.315239

    View details for PubMedID 33086865

  • Toward Automated Detection of Peripheral Artery Disease Using Electronic Health Records Vy Thuy Ho, Leeper, N., Shah, N., Ross, E. MOSBY-ELSEVIER. 2020: E41
  • Identifying dietary and nutritional risk factors for symptomatic peripheral arterial disease using the UK biobank cohort study Kaufman, A., Fukaya, E., Leeper, N., Ross, E. SAGE PUBLICATIONS LTD. 2020: NP5
  • The impact of low-dose anticoagulation therapy on peripheral artery disease: insights from the VOYAGER trial. Cardiovascular research Fukaya, E. n., Leeper, N. J. 2020; 116 (12): e156–e158

    View details for DOI 10.1093/cvr/cvaa225

    View details for PubMedID 32980875

  • Real-World Predictors of Major Adverse Cardiovascular Events and Major Adverse Limb Events Among Patients with Chronic Coronary Artery Disease and/or Peripheral Arterial Disease. Advances in therapy Berger, A., Simpson, A., Leeper, N., Murphy, B., Nordstrom, B., Ting, W., Zhao, Q., Berger, J. 2019

    Abstract

    INTRODUCTION: Collectively, coronary artery disease (CAD) and peripheral artery disease (PAD) are highly prevalent and are associated with increased risk of major adverse cardiovascular events (MACE) and major adverse limb events (MALE). Improved ability to identify those at highest risk of these events may help optimize secondary prevention efforts in this population.METHODS: Using the Optum Integrated Database, a healthcare claims database linked to electronic medical records (EMR), we identified patients with CAD and/or PAD between January 1, 2009, and September 30, 2016. Index date was the earliest date on which chronic and stable disease was established. Follow-up ran from index date until earliest of patient death, plan disenrollment, or end of study. We developed multivariate Cox proportional hazards models to identify predictors of MACE and/or MALE, limited to measures presumed available to clinicians during patient encounters (e.g., age, presence of selected comorbidities).RESULTS: A total of 20,932 patients met all selection criteria; 86.9% had CAD and 26.1% had PAD; 13% (n=2753) experienced MACE and/or MALE during a mean follow-up of 2.3years, for a rate of 7.1 events per 100 person-years (PYs). We identified 11 predictors of MACE and/or MALE. Most (95.1%) patients had≥1 predictors; 34.0% and 6.9% had≥4 and≥6, respectively. Incidence of MACE and/or MALE was strongly correlated with number of predictors (r2=0.98), ranging from 2.3 per 100 PYs among those without predictors (4.9% of patients) to 18.7 per 100 PYs among those with≥6 (6.9%). Patients with≥1 predictor experienced 7.4 MACE and/or MALE per 100 PYs.CONCLUSION: Readily identifiable predictors can be used to identify subgroups with chronic CAD and/or PAD at elevated risk of MACE and/or MALE. Further research is required to understand the degree to which these subgroups may benefit from early identification and treatment with secondary prevention therapies.FUNDING: Janssen Pharmaceuticals.

    View details for DOI 10.1007/s12325-019-01132-z

    View details for PubMedID 31705434

  • Resolvin D1 promotes the targeting and clearance of necroptotic cells. Cell death and differentiation Gerlach, B. D., Marinello, M., Heinz, J., Rymut, N., Sansbury, B. E., Riley, C. O., Sadhu, S., Hosseini, Z., Kojima, Y., Tang, D. D., Leeper, N. J., Spite, M., Barroso, M., Rayner, K. J., Fredman, G. 2019

    Abstract

    Inflammation-resolution is a protective response that is mediated by specialized pro-resolving mediators (SPMs). The clearance of dead cells or efferocytosis is a critical cellular program of inflammation-resolution. Impaired efferocytosis can lead to tissue damage in prevalent human diseases, like atherosclerosis. Therefore understanding mechanisms associated with swift clearance of dead cells is of utmost clinical importance. Recently, the accumulation of necroptotic cells (NCs) was observed in human plaques and we postulated that this is due to defective clearance programs. Here we present evidence that NCs are inefficiently taken up by macrophages because they have increased surface expression of a well-known "don't eat me" signal called CD47. High levels of CD47 on NCs stimulated RhoA-pMLC signaling in macrophages that promoted "nibbling", rather than whole-cell engulfment of NCs. Anti-CD47 blocking antibodies limited RhoA-p-MLC signaling and promoted whole-cell NC engulfment. Treatment with anti-CD47 blocking antibodies to Ldlr-/- mice with established atherosclerosis decreased necrotic cores, limited the accumulation of plaque NCs and increased lesional SPMs, including Resolvin D1 (RvD1) compared with IgG controls. Mechanistically, RvD1 promoted whole-cell engulfment of NCs by decreasing RhoA signaling and activating CDC42. RvD1 specifically targeted NCs for engulfment by facilitating the release of the well-known "eat me signal" called calreticulin from macrophages in a CDC42 dependent manner. Lastly, RvD1 enhanced the clearance of NCs in advanced murine plaques. Together, these results suggest new molecules and signaling associated with the clearance of NCs, provide a new paradigm for the regulation of inflammation-resolution, and offer a potential treatment strategy for diseases where NCs underpin the pathology.

    View details for DOI 10.1038/s41418-019-0370-1

    View details for PubMedID 31222041

  • Incidence and Cost of Major Adverse Cardiovascular Events and Major Adverse Limb Events in Patients With Chronic Coronary Artery Disease or Peripheral Artery Disease AMERICAN JOURNAL OF CARDIOLOGY Berger, A., Simpson, A., Bhagnani, T., Leeper, N. J., Murphy, B., Nordstrom, B., Ting, W., Zhao, Q., Berger, J. S. 2019; 123 (12): 1893–99
  • A Comprehensive Evaluation of Lifestyle and Social Factors Related to Peripheral Artery Disease Events in a Large Longitudinal Study Ross, E., Leeper, N., Ingelsson, E. MOSBY-ELSEVIER. 2019: E54–E55
  • Clonal Smooth Muscle Cell Expansion, Autophagy, and Vascular Integrity in Aortic Aneurysm Disease. Arteriosclerosis, thrombosis, and vascular biology Wang, Y., Nanda, V., Leeper, N. J. 2019; 39 (6): 982–83

    View details for DOI 10.1161/ATVBAHA.119.312739

    View details for PubMedID 31116606

  • Smooth Muscle Cells Contribute the Majority of Foam Cells in ApoE (Apolipoprotein E)-Deficient Mouse Atherosclerosis. Arteriosclerosis, thrombosis, and vascular biology Wang, Y., Dubland, J. A., Allahverdian, S., Asonye, E., Sahin, B., Jaw, J. E., Sin, D. D., Seidman, M. A., Leeper, N. J., Francis, G. A. 2019; 39 (5): 876-887

    Abstract

    Objective- Smooth muscle cells (SMCs) are the most abundant cells in human atherosclerotic lesions and are suggested to contribute at least 50% of atheroma foam cells. In mice, SMCs contribute fewer total lesional cells. The purpose of this study was to determine the contribution of SMCs to total foam cells in apolipoprotein E-deficient (ApoE-/-) mice, and the utility of these mice to model human SMC foam cell biology and interventions. Approach and Results- Using flow cytometry, foam cells in the aortic arch of ApoE-/- mice were characterized based on the expression of leukocyte-specific markers. Nonleukocyte foam cells increased from 37% of total foam cells in 27-week-old to 75% in 57-week-old male ApoE-/- mice fed a chow diet and were ≈70% in male and female ApoE-/- mice following 6 weeks of Western diet feeding. A similar contribution to total foam cells by SMCs was found using SMC-lineage tracing ApoE-/- mice fed the Western diet for 6 or 12 weeks. Nonleukocyte foam cells contributed a similar percentage of total atheroma cholesterol and exhibited lower expression of the cholesterol exporter ABCA1 (ATP-binding cassette transporter A1) when compared with leukocyte-derived foam cells. Conclusions- Consistent with previous studies of human atheromas, we present evidence that SMCs contribute the majority of atheroma foam cells in ApoE-/- mice fed a Western diet and a chow diet for longer periods. Reduced expression of ABCA1, also seen in human intimal SMCs, suggests a common mechanism for formation of SMC foam cells across species, and represents a novel target to enhance atherosclerosis regression.

    View details for DOI 10.1161/ATVBAHA.119.312434

    View details for PubMedID 30786740

  • Nanoparticle Therapy for Vascular Diseases ARTERIOSCLEROSIS THROMBOSIS AND VASCULAR BIOLOGY Flores, A. M., Ye, J., Jarr, K., Hosseini-Nassab, N., Smith, B. R., Leeper, N. J. 2019; 39 (4): 635–46
  • Predicting Future Cardiovascular Events in Patients With Peripheral Artery Disease Using Electronic Health Record Data CIRCULATION-CARDIOVASCULAR QUALITY AND OUTCOMES Ross, E., Jung, K., Dudley, J. T., Li, L., Leeper, N. J., Shah, N. H. 2019; 12 (3)
  • Predicting Future Cardiovascular Events in Patients With Peripheral Artery Disease Using Electronic Health Record Data. Circulation. Cardiovascular quality and outcomes Ross, E. G., Jung, K., Dudley, J. T., Li, L., Leeper, N. J., Shah, N. H. 2019; 12 (3): e004741

    Abstract

    BACKGROUND: Patients with peripheral artery disease (PAD) are at risk of major adverse cardiac and cerebrovascular events. There are no readily available risk scores that can accurately identify which patients are most likely to sustain an event, making it difficult to identify those who might benefit from more aggressive intervention. Thus, we aimed to develop a novel predictive model-using machine learning methods on electronic health record data-to identify which PAD patients are most likely to develop major adverse cardiac and cerebrovascular events.METHODS AND RESULTS: Data were derived from patients diagnosed with PAD at 2 tertiary care institutions. Predictive models were built using a common data model that allowed for utilization of both structured (coded) and unstructured (text) data. Only data from time of entry into the health system up to PAD diagnosis were used for modeling. Models were developed and tested using nested cross-validation. A total of 7686 patients were included in learning our predictive models. Utilizing almost 1000 variables, our best predictive model accurately determined which PAD patients would go on to develop major adverse cardiac and cerebrovascular events with an area under the curve of 0.81 (95% CI, 0.80-0.83).CONCLUSIONS: Machine learning algorithms applied to data in the electronic health record can learn models that accurately identify PAD patients at risk of future major adverse cardiac and cerebrovascular events, highlighting the great potential of electronic health records to provide automated risk stratification for cardiovascular diseases. Common data models that can enable cross-institution research and technology development could potentially be an important aspect of widespread adoption of newer risk-stratification models.

    View details for PubMedID 30857412

  • Nanoparticle Therapy for Vascular Diseases. Arteriosclerosis, thrombosis, and vascular biology Flores, A. M., Ye, J., Jarr, K., Hosseini-Nassab, N., Smith, B. R., Leeper, N. J. 2019: ATVBAHA118311569

    Abstract

    Nanoparticles promise to advance strategies to treat vascular disease. Since being harnessed by the cancer field to deliver safer and more effective chemotherapeutics, nanoparticles have been translated into applications for cardiovascular disease. Systemic exposure and drug-drug interactions remain a concern for nearly all cardiovascular therapies, including statins, antithrombotic, and thrombolytic agents. Moreover, off-target effects and poor bioavailability have limited the development of completely new approaches to treat vascular disease. Through the rational design of nanoparticles, nano-based delivery systems enable more efficient delivery of a drug to its therapeutic target or even directly to the diseased site, overcoming biological barriers and enhancing a drug's therapeutic index. In addition, advances in molecular imaging have led to the development of theranostic nanoparticles that may simultaneously act as carriers of both therapeutic and imaging payloads. The following is a summary of nanoparticle therapy for atherosclerosis, thrombosis, and restenosis and an overview of recent major advances in the targeted treatment of vascular disease.

    View details for PubMedID 30786744

  • Incidence and Cost of Major Adverse Cardiovascular Events and Major Adverse Limb Events in Patients With Chronic Coronary Artery Disease or Peripheral Artery Disease. The American journal of cardiology Berger, A. n., Simpson, A. n., Bhagnani, T. n., Leeper, N. J., Murphy, B. n., Nordstrom, B. n., Ting, W. n., Zhao, Q. n., Berger, J. S. 2019

    Abstract

    Chronic coronary artery disease (CAD) and peripheral artery disease (PAD) are both associated with elevated risks of major adverse cardiovascular events (MACE) and major adverse limb events (MALE). The frequency of these events in patients with CAD or PAD, and their corresponding costs, are not well understood. Accordingly, we describe the incidence and cost of both MACE and MALE in patients with CAD or PAD. Using a database that included healthcare claims linked to electronic medical records, we identified patients with evidence of chronic CAD and PAD, respectively, between January 1, 2009, and September 30, 2016. We assessed the occurrence of MACE (defined as myocardial infarction, stroke, or cardiovascular-related death) and MALE (critical limb ischemia, amputation, or peripheral artery disease-related revascularization). A total of 99,730 patients met all selection criteria: 86.0% had CAD, 25.8% had PAD, and 11.8% had both. Mean (±standard deviation) age was 67.7 (±11.5) years and 59.8% were male. During follow-up (mean: 1.8 years), 13.6% experienced MACE or MALE (6.3 per 100 person-years [PYs]), predominantly MACE (9.6% [4.3 per 100 PYs]). Adjusted 1-year healthcare costs were

  • Smooth muscle cells contribute the majority of foam cells in apolipoprotein E-deficient mouse atherosclerosis Arteriosclerosis, Thrombosis, and Vascular Biology (In press) Wang, Y., Dubland, J., Allahverdian, S., Asonye, E., Sahin, B., Jaw, J., Sin, D., Seidman, M., Leeper, N., Francis, G. 2019 : 876–87

    Abstract

    Objective- Smooth muscle cells (SMCs) are the most abundant cells in human atherosclerotic lesions and are suggested to contribute at least 50% of atheroma foam cells. In mice, SMCs contribute fewer total lesional cells. The purpose of this study was to determine the contribution of SMCs to total foam cells in apolipoprotein E-deficient (ApoE-/-) mice, and the utility of these mice to model human SMC foam cell biology and interventions. Approach and Results- Using flow cytometry, foam cells in the aortic arch of ApoE-/- mice were characterized based on the expression of leukocyte-specific markers. Nonleukocyte foam cells increased from 37% of total foam cells in 27-week-old to 75% in 57-week-old male ApoE-/- mice fed a chow diet and were ≈70% in male and female ApoE-/- mice following 6 weeks of Western diet feeding. A similar contribution to total foam cells by SMCs was found using SMC-lineage tracing ApoE-/- mice fed the Western diet for 6 or 12 weeks. Nonleukocyte foam cells contributed a similar percentage of total atheroma cholesterol and exhibited lower expression of the cholesterol exporter ABCA1 (ATP-binding cassette transporter A1) when compared with leukocyte-derived foam cells. Conclusions- Consistent with previous studies of human atheromas, we present evidence that SMCs contribute the majority of atheroma foam cells in ApoE-/- mice fed a Western diet and a chow diet for longer periods. Reduced expression of ABCA1, also seen in human intimal SMCs, suggests a common mechanism for formation of SMC foam cells across species, and represents a novel target to enhance atherosclerosis regression.

    View details for DOI 10.1161/ATVBAHA.119.312434

  • Clinical and Genetic Determinants of Varicose Veins. Circulation Fukaya, E., Flores, A. M., Lindholm, D., Gustafsson, S., Zanetti, D., Ingelsson, E., Leeper, N. J. 2018; 138 (25): 2869–80

    Abstract

    BACKGROUND: Varicose veins are a common problem with no approved medical therapies. Although it is believed that varicose vein pathogenesis is multifactorial, there is limited understanding of the genetic and environmental factors that contribute to their formation. Large-scale studies of risk factors for varicose veins may highlight important aspects of pathophysiology and identify groups at increased risk for disease.METHODS: We applied machine learning to agnostically search for risk factors of varicose veins in 493519 individuals in the UK Biobank. Predictors were further studied with univariable and multivariable Cox regression analyses (2441 incident events). A genome-wide association study of varicose veins was also performed among 337536 unrelated individuals (9577 cases) of white British descent, followed by expression quantitative loci and pathway analyses. Because height emerged as a new candidate risk factor, we performed mendelian randomization analyses to assess a potential causal role for height in varicose vein development.RESULTS: Machine learning confirmed several known (age, sex, obesity, pregnancy, history of deep vein thrombosis) and identified several new risk factors for varicose vein disease, including height. After adjustment for traditional risk factors in Cox regression, greater height remained independently associated with varicose veins (hazard ratio for upper versus lower quartile, 1.74; 95% CI, 1.51-2.01; P<0.0001). A genome-wide association study identified 30 new genome-wide significant loci, identifying pathways involved in vascular development and skeletal/limb biology. Mendelian randomization analysis provided evidence that increased height is causally related to varicose veins (inverse-variance weighted: odds ratio, 1.26; P=2.07*10-16).CONCLUSIONS: Using data from nearly a half-million individuals, we present a comprehensive genetic and epidemiological study of varicose veins. We identified novel clinical and genetic risk factors that provide pathophysiological insights and could help future improvements of treatment of varicose vein disease.

    View details for PubMedID 30566020

  • Functional regulatory mechanism of smooth muscle cell-restricted LMOD1 coronary artery disease locus PLOS GENETICS Nanda, V., Wang, T., Pjanic, M., Liu, B., Trieu Nguyen, Matic, L., Hedin, U., Koplev, S., Ma, L., Franzen, O., Ruusalepp, A., Schadt, E. E., Bjorkegren, J. M., Montgomery, S. B., Snyder, M. P., Quertermous, T., Leeper, N. J., Miller, C. L. 2018; 14 (11)
  • Association of Blood Pressure Measurements With Peripheral Artery Disease Events: Reanalysis of the ALLHAT Data CIRCULATION Itoga, N. K., Tawfik, D. S., Lee, C. K., Maruyama, S., Leeper, N. J., Chang, T. I. 2018; 138 (17): 1805–14
  • Loss of CDKN2B Promotes Fibrosis via Increased Fibroblast Differentiation Rather Than Proliferation AMERICAN JOURNAL OF RESPIRATORY CELL AND MOLECULAR BIOLOGY Scruggs, A. M., Koh, H. B., Tripathi, P., Leeper, N. J., White, E. S., Huang, S. K. 2018; 59 (2): 200–214

    Abstract

    Idiopathic pulmonary fibrosis (IPF) is a devastating lung disease characterized by excessive scarring and fibroblast activation. We previously showed that fibroblasts from patients with IPF are hypermethylated at the CDKN2B gene locus, resulting in decreased CDKN2B expression. Here, we examine how diminished CDKN2B expression in normal and IPF fibroblasts affect fibroblast function, and how loss of CDKN2B contributes to IPF pathogenesis. We first confirmed that protein expression of CDKN2B was diminished in IPF lungs in situ. Loss of CDKN2B was especially notable in regions of increased myofibroblasts and fibroblastic foci. The degree of CDKN2B hypermethylation was particularly elevated in patients with radiographic honeycombing, a marker of more advanced fibrosis, and increased DNA methylation correlated with decreased expression. Although CDKN2B is traditionally considered a cell cycle inhibitor, loss of CDKN2B did not result in an increase in fibroblast proliferation, but instead was associated with an increase in myofibroblast differentiation. An increase in myofibroblast differentiation was not observed when CDKN2A was silenced. Loss of CDKN2B was associated with an increase in the transcription factors serum response factor and myocardin-related transcription factor A, and overexpression of CDKN2B in IPF fibroblasts inhibited myofibroblast differentiation. Finally, decreased CDKN2B expression was noted in fibroblasts from a murine model of fibrosis, and Cdkn2b-/- mice developed greater histologic fibrosis after bleomycin injury. These findings identify a novel function for CDKN2B that differs from its conventional designation as a cell cycle inhibitor and demonstrate the importance of this protein in pulmonary fibrosis.

    View details for PubMedID 29420051

  • Trends in Rates of Lower Extremity Amputation Among Patients With End-stage Renal Disease Who Receive Dialysis. JAMA internal medicine Franz, D., Zheng, Y., Leeper, N. J., Chandra, V., Montez-Rath, M., Chang, T. I. 2018

    Abstract

    Patients with end-stage renal disease (ESRD) who receive dialysis are at high risk of lower extremity amputation. Recent studies indicate decreasing rates of lower extremity amputation in non-ESRD populations, but contemporary data for patients with ESRD who receive dialysis are lacking.To assess rates of lower extremity amputation among patients with ESRD who receive dialysis during a recent 15-year period; to analyze whether those rates differed by age, sex, diabetes, or geographic region; and to determine 1-year mortality rates in this population after lower extremity amputation.This retrospective study of 3 700 902 records obtained from a US national registry of patients with ESRD who receive dialysis assessed cross-sectional cohorts for each calendar year from 2000 through 2014. Adult patients with prevalent ESRD treated with hemodialysis or peritoneal dialysis covered by Medicare Part A and B on January 1 of each cohort year were included. Data analysis was conducted from August 2017 to April 2018.Age, sex, diabetes, and hospital referral region.Annual rates per 100 person-years of nontraumatic major (above- or below-knee) and minor (below-ankle) amputations.For each annual cohort, there were fewer women (47.5% in 2000, 46.2% in 2005, 44.9% in 2010, and 44.0% in 2014) than men, more than half the patients were white individuals (58.1% in 2000, 56.9% in 2005, 56.9% in 2010, and 56.7% in 2014), and a small proportion were employed (13.9% in 2000, 15.1% in 2005, 16.1% in 2010, and 16.5% in 2014). The rate of lower extremity amputations for patients with ESRD who receive dialysis decreased by 51.0% from 2000 to 2014, driven primarily by a decrease in the rate of major amputations (5.42 [95% CI, 5.28-5.56] in 2000 vs 2.66 [95% CI, 2.59-2.72] per 100 person-years in 2014). Patients with diabetes had amputation rates more than 5 times as high as patients without diabetes. Patients younger than 65 years had higher adjusted amputation rates than older patients, and men had consistently higher adjusted amputation rates than women. Adjusted 1-year mortality rates after lower extremity amputation for patients with ESRD who receive dialysis decreased from 52.2% (95% CI, 50.9%-53.4%) in 2000 to 43.6% (95% CI, 42.5%-44.8%) in 2013. In general, amputation rates decreased among all regions from 2000 to 2014, but regional variability persisted across time despite adjustment for differences in patient demographics and comorbid conditions.Although rates of lower extremity amputations among US patients with ESRD who receive dialysis decreased by 51% during a recent 15-year period, mortality rates remained high, with nearly half of patients dying within a year after lower extremity amputation. Our results highlight the need for more research on ways to prevent lower extremity amputation in this extremely high-risk population.

    View details for DOI 10.1001/jamainternmed.2018.2436

    View details for PubMedID 29987332

  • Bioimpedance and New-Onset Heart Failure: A Longitudinal Study of >500 000 Individuals From the General Population JOURNAL OF THE AMERICAN HEART ASSOCIATION Lindholm, D., Fukaya, E., Leeper, N. J., Ingelsson, E. 2018; 7 (13)

    Abstract

    Heart failure constitutes a high burden on patients and society, but although lifetime risk is high, it is difficult to predict without costly or invasive testing. We aimed to establish new risk factors of heart failure, which potentially could enable early diagnosis and preemptive treatment.We applied machine learning in the UK Biobank in an agnostic search of risk factors for heart failure in 500 451 individuals, excluding individuals with prior heart failure. Novel factors were then subjected to several in-depth analyses, including multivariable Cox models of incident heart failure, and assessment of discrimination and calibration. Machine learning confirmed many known and putative risk factors for heart failure and identified several novel candidates. Mean reticulocyte volume appeared as one novel factor and leg bioimpedance another, the latter appearing as the most important new marker. Leg bioimpedance was lower in those who developed heart failure during an up to 9.8-year follow-up. When adjusting for known heart failure risk factors, leg bioimpedance was inversely related to heart failure (hazard ratio [95% confidence interval], 0.60 [0.48-0.73] and 0.75 [0.59-0.94], in age- and sex-adjusted and fully adjusted models, respectively, comparing the upper versus lower quartile). A model including leg bioimpedance, age, sex, and self-reported history of myocardial infarction showed good discrimination for future heart failure hospitalization (Concordance index [C-index]=0.82) and good calibration.Leg bioimpedance is inversely associated with heart failure incidence in the general population. A simple model of exclusively noninvasive measures, combining leg bioimpedance with history of myocardial infarction, age, and sex provides accurate predictive capacity.

    View details for PubMedID 29959136

  • Association of Blood Pressure Measurements with Peripheral Arterial Disease Events: A Reanalysis of the ALLHAT Data. Circulation Itoga, N. K., Tawfik, D. S., Lee, C. K., Maruyama, S., Leeper, N. J., Chang, T. I. 2018

    Abstract

    Background -Current guidelines recommend treating hypertension in patients with peripheral arterial disease (PAD) to reduce the risk of cardiac events and stroke, but the effect of reducing blood pressure on lower extremity PAD events is largely unknown. We investigated the association of blood pressure with lower extremity PAD events using data from the Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial (ALLHAT). Methods -ALLHAT investigated the effect of different antihypertensive medication classes (chlorthalidone, amlodipine, lisinopril, or doxazosin) on cardiovascular events. Using these data, the primary outcome in our analysis was time to first lower extremity PAD event, defined as PAD-related hospitalization, procedures, medical treatment, or PAD-related death. Given the availability of longitudinal standardized blood pressure measurements, we analyzed systolic blood pressure (SBP), diastolic blood pressure (DBP) and pulse pressure (PP) as time-varying categorical variables (reference categories 120-129 mm Hg for SBP, 70-79 mm Hg for DBP, and 45-54 mm Hg for PP) in separate models. We used extended Cox regression with death as a competing risk to calculate the association of each BP component with PAD events, and report the results as sub-distribution hazard ratios (HR) and 95% confidence intervals (CI). Results -The present analysis included 33,357 patients with an average age of 67.4 years, 53.1% men, 59.7% white race, and 36.2% with diabetes mellitus. The median baseline blood pressure was 146/84 mm Hg. Participants were followed for a median of 4.3 (IQR 3.6-5.3) years, during which time 1,489 (4.5%) had a lower extremity PAD event, and 4,148 (12.4%) died. In models adjusted for demographic and clinical characteristics, SBP <120 mm Hg was associated with a 26% (CI 5-52%, P=0.015) higher hazard and SBP≥160 mm Hg was associated with a 21% (CI 0-48%, P=0.050) higher hazard for a PAD event, compared with SBP 120-129 mm Hg. In contrast, lower, but not higher, DBP was associated with higher hazard of PAD events: for DBP <60 mm Hg HR = 1.72 (CI 1.38 - 2.16). PP had a U-shaped association with PAD events. Conclusions -In this re-analysis of data from ALLHAT, we found a higher rate of lower extremity PAD events with higher and lower SBP and PP, and with lower DBP. Given the recent revised blood pressure guidelines advocating lower SBP targets for overall cardiovascular risk reduction, further refinement of optimal blood pressure targets specific to PAD is needed. Clinical Trial Registration -URL: www.clinicaltrials.gov Unique identifier: NCT00000542.

    View details for PubMedID 29930023

  • Thrombotic Regulation From the Endothelial Cell Perspectives ARTERIOSCLEROSIS THROMBOSIS AND VASCULAR BIOLOGY Wang, M., Hao, H., Leeper, N. J., Zhu, L., Early Career Comm 2018; 38 (6): E90–E95

    View details for PubMedID 29793992

  • Clinical and genetic determinants of varicose veins: a prospective, community-based prospective study of similar to 500,000 individuals Fukaya, E., Flores, A., Lindholm, D., Gustafsson, S., Ingelsson, E., Leeper, N. SAGE PUBLICATIONS LTD. 2018: 300
  • Non-coding RNAs: key regulators of smooth muscle cell fate in vascular disease CARDIOVASCULAR RESEARCH Leeper, N. J., Maegdefessel, L. 2018; 114 (4): 611–21

    Abstract

    The vascular smooth muscle cell (SMC) is one of the most plastic cells in the body. Understanding how non-coding RNAs (ncRNAs) regulate SMC cell-fate decision making in the vasculature has significantly enhanced our understanding of disease development, and opened up exciting new avenues for potential therapeutic applications. Recent studies on SMC physiology have in addition challenged our traditional view on their role and contribution to vascular disease, mainly in the setting of atherosclerosis as well as aneurysm disease, and restenosis after angioplasties. The impact of SMC behaviour on vascular disease is now recognized to be context dependent; SMC proliferation and migration can be harmful or beneficial, whereas their apoptosis, senescence, and switching into a more macrophage-like phenotype can promote inflammation and disease progression. This is in particular true for atherosclerosis-related diseases, where proliferation of SMCs was believed to promote lesion formation, but may also prevent plaque rupture by stabilizing the fibrous cap. Based on newer findings of genetic lineage tracing studies, it was revealed that SMC phenotypic switching can result in less-differentiated forms that lack classical SMC markers while exhibiting functions more related to macrophage-like cells. This switching can directly promote atherogenesis. The aim of this current review is to summarize and discuss how ncRNAs (mainly microRNAs and long ncRNAs) are involved in SMC plasticity, and how they directly affect vascular disease development and progression. Finally, we want to critically assess where potential future therapies could be useful to influence the burden of vascular diseases.

    View details for PubMedID 29300828

    View details for PubMedCentralID PMC5852528

  • Consideration of Sex Differences in Design and Reporting of Experimental Arterial Pathology Studies-Statement From ATVB Council ARTERIOSCLEROSIS THROMBOSIS AND VASCULAR BIOLOGY Robinet, P., Milewicz, D. M., Cassis, L. A., Leeper, N. J., Lu, H. S., Smith, J. D. 2018; 38 (2): 292–303

    Abstract

    There are many differences in arterial diseases between men and women, including prevalence, clinical manifestations, treatments, and prognosis. The new policy of the National Institutes of Health, which requires the inclusion of sex as a biological variable for preclinical studies, aims to foster new mechanistic insights and to enhance our understanding of sex differences in human diseases. The purpose of this statement is to suggest guidelines for designing and reporting sex as a biological variable in animal models of atherosclerosis, thoracic and abdominal aortic aneurysms, and peripheral arterial disease. We briefly review sex differences of these human diseases and their animal models, followed by suggestions on experimental design and reporting of animal studies for these vascular pathologies.

    View details for PubMedID 29301789

    View details for PubMedCentralID PMC5785439

  • Trends in Rates of Lower Extremity Amputation Among Patients With End-Stage Renal Disease Who Receive Dialysis JAMA Internal Medicine Franz, D., Zheng, Y., Leeper, N. J., Chandra, V., Montez-Rath, M., Chang, T. I. 2018
  • Functional regulatory mechanism of smooth muscle cell-restricted LMOD1 coronary artery disease locus. PLoS genetics Nanda, V. n., Wang, T. n., Pjanic, M. n., Liu, B. n., Nguyen, T. n., Matic, L. P., Hedin, U. n., Koplev, S. n., Ma, L. n., Franzén, O. n., Ruusalepp, A. n., Schadt, E. E., Björkegren, J. L., Montgomery, S. B., Snyder, M. P., Quertermous, T. n., Leeper, N. J., Miller, C. L. 2018; 14 (11): e1007755

    Abstract

    Recent genome-wide association studies (GWAS) have identified multiple new loci which appear to alter coronary artery disease (CAD) risk via arterial wall-specific mechanisms. One of the annotated genes encodes LMOD1 (Leiomodin 1), a member of the actin filament nucleator family that is highly enriched in smooth muscle-containing tissues such as the artery wall. However, it is still unknown whether LMOD1 is the causal gene at this locus and also how the associated variants alter LMOD1 expression/function and CAD risk. Using epigenomic profiling we recently identified a non-coding regulatory variant, rs34091558, which is in tight linkage disequilibrium (LD) with the lead CAD GWAS variant, rs2820315. Herein we demonstrate through expression quantitative trait loci (eQTL) and statistical fine-mapping in GTEx, STARNET, and human coronary artery smooth muscle cell (HCASMC) datasets, rs34091558 is the top regulatory variant for LMOD1 in vascular tissues. Position weight matrix (PWM) analyses identify the protective allele rs34091558-TA to form a conserved Forkhead box O3 (FOXO3) binding motif, which is disrupted by the risk allele rs34091558-A. FOXO3 chromatin immunoprecipitation and reporter assays show reduced FOXO3 binding and LMOD1 transcriptional activity by the risk allele, consistent with effects of FOXO3 downregulation on LMOD1. LMOD1 knockdown results in increased proliferation and migration and decreased cell contraction in HCASMC, and immunostaining in atherosclerotic lesions in the SMC lineage tracing reporter mouse support a key role for LMOD1 in maintaining the differentiated SMC phenotype. These results provide compelling functional evidence that genetic variation is associated with dysregulated LMOD1 expression/function in SMCs, together contributing to the heritable risk for CAD.

    View details for PubMedID 30444878

  • A Missing LNC in Vascular Diseases CIRCULATION RESEARCH Cooke, J. P., Leeper, N. J. 2017; 121 (4): 320–22

    View details for PubMedID 28775007

    View details for PubMedCentralID PMC5637485

  • MiRNA-210 Enhances Fibrous Cap Stability in Advanced Atherosclerotic Lesions Eken, S. M., Jin, H., Chernogubova, E., Li, Y., Simon, N., Sun, C., Korzunowicz, G., Busch, A., Backlund, A., Osterholm, C., Razuvaev, A., Renne, T., Eckstein, H. H., Pelisek, J., Eriksson, P., Diez, M., Perisic, L., Schellinger, I. N., Raaz, U., Leeper, N. J., Hansson, G. K., Paulsson-Berne, G., Hedin, U., Maegdefessel, L. LIPPINCOTT WILLIAMS & WILKINS. 2017
  • A CD47-associated super-enhancer links pro-inflammatory signalling to CD47 upregulation in breast cancer NATURE COMMUNICATIONS Betancur, P. A., Abraham, B. J., Yiu, Y. Y., Willingham, S. B., Khameneh, F., Zarnegar, M., Kuo, A. H., McKenna, K., Kojima, Y., Leeper, N. J., Ho, P., Gip, P., Swigut, T., Sherwood, R. I., Clarke, M. F., Somlo, G., Young, R. A., Weissman, I. L. 2017; 8

    Abstract

    CD47 is a cell surface molecule that inhibits phagocytosis of cells that express it by binding to its receptor, SIRPα, on macrophages and other immune cells. CD47 is expressed at different levels by neoplastic and normal cells. Here, to reveal mechanisms by which different neoplastic cells generate this dominant 'don't eat me' signal, we analyse the CD47 regulatory genomic landscape. We identify two distinct super-enhancers (SEs) associated with CD47 in certain cancer cell types. We show that a set of active constituent enhancers, located within the two CD47 SEs, regulate CD47 expression in different cancer cell types and that disruption of CD47 SEs reduces CD47 gene expression. Finally we report that the TNF-NFKB1 signalling pathway directly regulates CD47 by interacting with a constituent enhancer located within a CD47-associated SE specific to breast cancer. These results suggest that cancers can evolve SE to drive CD47 overexpression to escape immune surveillance.

    View details for DOI 10.1038/ncomms14802

    View details for Web of Science ID 000398343600001

    View details for PubMedID 28378740

  • The Intersection of Genome-Wide Association Studies and High-Throughput Small Interfering Ribonucleic Acid Screens Allows for the Identification of Novel Pathways Relevant to Atherosclerosis. JACC. Basic to translational science Nanda, V., Xiao, S., Ye, J., Leeper, N. J. 2017; 2 (2): 209–11

    Abstract

    It is now known that the internalization and transcytosis of low density lipoprotein (LDL) in the vessel wall occurs through molecular pathways independent of the LDL receptor. In a study recently published in Nature Communications, investigators cross-referenced results from a genome-wide ribonucleic acid interference screen with targets identified in publicly-available genome-wide association studies datasets to identify activin-like kinase 1 as a novel driver of this process. This approach has relevance to the field of atherosclerosis, and could be used as a model for the prioritization of future "hits" in large-scale genomic screens.

    View details for PubMedID 30167568

  • "Attack of the Clones": Commonalities Between Cancer and Atherosclerosis. Circulation research DiRenzo, D., Owens, G. K., Leeper, N. J. 2017; 120 (4): 624-626

    View details for DOI 10.1161/CIRCRESAHA.116.310091

    View details for PubMedID 28209794

  • Evaluation of Cell Therapy on Exercise Performance and Limb Perfusion in Peripheral Artery Disease: The CCTRN Patients with Intermittent Claudication Injected with ALDH Bright Cells (PACE) Trial. Circulation Perin, E. C., Murphy, M. P., March, K. L., Bolli, R., Loughran, J., Yang, P. C., Leeper, N. J., Dalman, R. L., Alexander, J. Q., Henry, T. D., Traverse, J. H., Pepine, C. J., Anderson, R. D., Berceli, S., Willerson, J. T., Muthupillai, R., Gahremanpour, A. A., Raveendran, G., Velazquez, O. C., Hare, J. M., Schulman, I. H., Kasi, V. S., Hiatt, W. R., Ambale-Venkatesh, B., Lima, J. A., Taylor, D. A., Resende, M. M., Gee, A. P., Durett, A. G., Bloom, J., Richman, S., G'Sell, P., Williams, S., Khan, F., Ross, E. G., Santoso, M. R., Goldman, J., Leach, D., Handberg, E., Cheong, B. Y., Piece, N. A., Difede, D., Bruhn-Ding, B., Caldwell, E., Bettencourt, J., Lai, D., Piller, L. B., Simpson, L. M., Cohen, M., Sayre, S. L., Vojvodic, R. W., Moyé, L., Ebert, R. F., Simari, R. D., Hirsch, A. T. 2017

    Abstract

    Atherosclerotic peripheral artery disease affects 8% to 12% of Americans >65 years of age and is associated with a major decline in functional status, increased myocardial infarction and stroke rates, and increased risk of ischemic amputation. Current treatment strategies for claudication have limitations. PACE (Patients With Intermittent Claudication Injected With ALDH Bright Cells) is a National Heart, Lung, and Blood Institute-sponsored, randomized, double-blind, placebo-controlled, phase 2 exploratory clinical trial designed to assess the safety and efficacy of autologous bone marrow-derived aldehyde dehydrogenase bright (ALDHbr) cells in patients with peripheral artery disease and to explore associated claudication physiological mechanisms.All participants, randomized 1:1 to receive ALDHbr cells or placebo, underwent bone marrow aspiration and isolation of ALDHbr cells, followed by 10 injections into the thigh and calf of the index leg. The coprimary end points were change from baseline to 6 months in peak walking time (PWT), collateral count, peak hyperemic popliteal flow, and capillary perfusion measured by magnetic resonance imaging, as well as safety.A total of 82 patients with claudication and infrainguinal peripheral artery disease were randomized at 9 sites, of whom 78 had analyzable data (57 male, 21 female patients; mean age, 66±9 years). The mean±SEM differences in the change over 6 months between study groups for PWT (0.9±0.8 minutes; 95% confidence interval [CI] -0.6 to 2.5; P=0.238), collateral count (0.9±0.6 arteries; 95% CI, -0.2 to 2.1; P=0.116), peak hyperemic popliteal flow (0.0±0.4 mL/s; 95% CI, -0.8 to 0.8; P=0.978), and capillary perfusion (-0.2±0.6%; 95% CI, -1.3 to 0.9; P=0.752) were not significant. In addition, there were no significant differences for the secondary end points, including quality-of-life measures. There were no adverse safety outcomes. Correlative relationships between magnetic resonance imaging measures and PWT were not significant. A post hoc exploratory analysis suggested that ALDHbr cell administration might be associated with an increase in the number of collateral arteries (1.5±0.7; 95% CI, 0.1-2.9; P=0.047) in participants with completely occluded femoral arteries.ALDHbr cell administration did not improve PWT or magnetic resonance outcomes, and the changes in PWT were not associated with the anatomic or physiological magnetic resonance imaging end points. Future peripheral artery disease cell therapy investigational trial design may be informed by new anatomic and perfusion insights.URL: http://www.clinicaltrials.gov. Unique identifier: NCT01774097.

    View details for DOI 10.1161/CIRCULATIONAHA.116.025707

    View details for PubMedID 28209728

  • MicroRNA-210 Enhances Fibrous Cap Stability in Advanced Atherosclerotic Lesions CIRCULATION RESEARCH Eken, S. M., Jin, H., Chernogubova, E., Li, Y., Simon, N., Sun, C., Korzunowicz, G., Busch, A., Backlund, A., Osterholm, C., Razuvaev, A., Renne, T., Eckstein, H. H., Pelisek, J., Eriksson, P., Diez, M. G., Matic, L. P., Schellinger, I. N., Raaz, U., Leeper, N. J., Hansson, G. K., Paulsson-Berne, G., Hedin, U., Maegdefessel, L. 2017; 120 (4): 633-?

    Abstract

    In the search for markers and modulators of vascular disease, microRNAs (miRNAs) have emerged as potent therapeutic targets.To investigate miRNAs of clinical interest in patients with unstable carotid stenosis at risk of stroke.Using patient material from the BiKE (Biobank of Karolinska Endarterectomies), we profiled miRNA expression in patients with stable versus unstable carotid plaque. A polymerase chain reaction-based miRNA array of plasma, sampled at the carotid lesion site, identified 8 deregulated miRNAs (miR-15b, miR-29c, miR-30c/d, miR-150, miR-191, miR-210, and miR-500). miR-210 was the most significantly downregulated miRNA in local plasma material. Laser capture microdissection and in situ hybridization revealed a distinct localization of miR-210 in fibrous caps. We confirmed that miR-210 directly targets the tumor suppressor gene APC (adenomatous polyposis coli), thereby affecting Wnt (Wingless-related integration site) signaling and regulating smooth muscle cell survival, as well as differentiation in advanced atherosclerotic lesions. Substantial changes in arterial miR-210 were detectable in 2 rodent models of vascular remodeling and plaque rupture. Modulating miR-210 in vitro and in vivo improved fibrous cap stability with implications for vascular disease.An unstable carotid plaque at risk of stroke is characterized by low expression of miR-210. miR-210 contributes to stabilizing carotid plaques through inhibition of APC, ensuring smooth muscle cell survival. We present local delivery of miR-210 as a therapeutic approach for prevention of atherothrombotic vascular events.

    View details for DOI 10.1161/CIRCRESAHA.116.309318

    View details for Web of Science ID 000394446200016

    View details for PubMedID 27895035

  • High-Density Lipoprotein Nanoparticle Imaging in Atherosclerotic Vascular Disease. JACC. Basic to translational science Leeper, N. J., Park, S. M., Smith, B. R. 2017; 2 (1): 98-100

    Abstract

    Nanoparticles promise to advance the field of cardiovascular theranostics. However, their sustained and targeted delivery remains an important obstacle. The body synthesizes some "natural" nanoparticles, including high-density lipoprotein (HDL), which may home to the atherosclerotic plaque and promote cholesterol efflux. In a recent article published in JACC: Cardiovascular Imaging, investigators generated modified, radiolabeled HDL nanoparticles and confirmed they accumulated in atherosclerotic lesions from several different species. These approaches hold promise for the noninvasive diagnosis of vulnerable plaque and in the stratification of patients in whom HDL-mimetic therapy may have a clinical benefit.

    View details for DOI 10.1016/j.jacbts.2017.01.005

    View details for PubMedID 30167557

    View details for PubMedCentralID PMC6113536

  • Baseline assessment and comparison of arterial anatomy, hyperemic flow, and skeletal muscle perfusion in peripheral artery disease: The Cardiovascular Cell Therapy Research Network "Patients with Intermittent Claudication Injected with ALDH Bright Cells" (CCTRN PACE) study AMERICAN HEART JOURNAL Venkatesh, B. A., Nauffal, V., Noda, C., Fujii, T., Yang, P. C., Bettencourt, J., Ricketts, E. P., Murphy, M., Leeper, N. J., Moye, L., Ebert, R. F., Muthupillai, R., Bluemke, D. A., Perin, E. C., Hirsch, A. T., Lima, J. A. 2017; 183: 24-34

    Abstract

    Peripheral artery disease (PAD) is important to public health as a major contributor to cardiovascular morbidity and mortality. Recent developments in magnetic resonance imaging (MRI) techniques permit improved assessment of PAD anatomy and physiology, and may serve as surrogate end points after proangiogenic therapies.The PACE study is a randomized, double-blind, placebo-controlled clinical trial designed to assess the physiologic impact and potential clinical efficacy of autologous bone marrow-derived ALDH(br) stem cells. The primary MRI end points of the study are as follows: (1) total collateral count, (2) calf muscle plasma volume (a measure of capillary perfusion) by dynamic contrast-enhanced MRI, and (3) peak hyperemic popliteal flow by phase-contrast MRI (PC-MRI).The interreader and intrareader and test-retest results demonstrated good-to-excellent reproducibility (interclass correlation coefficient range 0.61-0.98) for all magnetic resonance measures. The PAD participants (n=82) had lower capillary perfusion measured by calf muscle plasma volume (3.8% vs 5.6%) and peak hyperemic popliteal flow (4.1 vs 13.5mL/s) as compared with the healthy participants (n=16), with a significant level of collateralization.Reproducibility of the MRI primary end points in PACE was very good to excellent. The PAD participants exhibited decreased calf muscle capillary perfusion as well as arterial flow reserve when compared with healthy participants. The MRI tools used in PACE may advance PAD science by enabling accurate measurement of PAD microvascular anatomy and perfusion before and after stem cell or other PAD therapies.

    View details for DOI 10.1016/j.ahj.2016.09.013

    View details for PubMedID 27979038

  • High-Density Lipoprotein Nanoparticle Imaging in Atherosclerotic Vascular Disease JACC: Basic to Translational Science Leeper, N. J., Park, S., Smith, B. R. 2017; 2 (1): 98-100
  • Association Between Androgen Deprivation Therapy and Risk of Dementia JAMA ONCOLOGY Nead, K. T., Gaskin, G., Chester, C., Swisher-McClure, S., Leeper, N. J., Shah, N. H. 2017; 3 (1): 49-55

    Abstract

    A growing body of evidence supports a link between androgen deprivation therapy (ADT) and cognitive dysfunction, including Alzheimer disease. However, it is currently unknown whether ADT may contribute to the risk of dementia more broadly.To use an informatics approach to examine the association of ADT as a treatment for prostate cancer with the subsequent development of dementia (eg, senile dementia, vascular dementia, frontotemporal dementia, and Alzheimer dementia).In this cohort study, a text-processing method was used to analyze electronic medical record data from an academic medical center from 1994 to 2013, with a median follow-up of 3.4 years (interquartile range, 1.0-7.2 years). We identified 9455 individuals with prostate cancer who were 18 years or older at diagnosis with data recorded in the electronic health record and follow-up after diagnosis. We excluded 183 patients with a previous diagnosis of dementia. Our final cohort comprised 9272 individuals with prostate cancer, including 1826 men (19.7%) who received ADT.We tested the effect of ADT on the risk of dementia using propensity score-matched Cox proportional hazards regression models and Kaplan-Meier survival analysis.Among 9272 men with prostate cancer (mean [SD] age, 66.9 [10.9] years; 5450 [58.8%] white), there was a statistically significant association between use of ADT and risk of dementia (hazard ratio, 2.17; 95% CI, 1.58-2.99; P < .001). In sensitivity analyses, results were similar when excluding patients with Alzheimer disease (hazard ratio, 2.32; 95% CI, 1.73-3.12; P < .001). The absolute increased risk of developing dementia among those who received ADT was 4.4% at 5 years (7.9% among those who received ADT vs 3.5% in those who did not receive ADT). Analyses stratified by duration of ADT found that individuals with at least 12 months of ADT use had the greatest absolute increased risk of dementia (hazard ratio, 2.36; 95% CI, 1.64-3.38; P < .001). Kaplan-Meier analysis demonstrated that ADT users 70 years or older had the lowest cumulative probability of remaining dementia free (log-rank P < .001).Androgen deprivation therapy in the treatment of prostate cancer may be associated with an increased risk of dementia. This finding should be further evaluated in prospective studies.

    View details for DOI 10.1001/jamaoncol.2016.3662

    View details for Web of Science ID 000394257300011

  • Administration of ALDH Bright Cells to Patients With Intermittent Claudication: The NHLBI CCTRN PACE Trial Perin, E. C., Murphy, M., March, K., Bolli, R., Leeper, N. J., Yang, P. C., Alexander, J., Henry, T. D., Traverse, J. H., Pepine, C. J., Willerson, J. T., Velasquez, O., Hare, J. M., Kasi, V. S., Lima, J. A., Hiatt, W. R., Taylor, D. A., Gee, A. P., Moye, L., Ebert, R. F., Simari, R. D., Hirsch, A. T. LIPPINCOTT WILLIAMS & WILKINS. 2016: E709
  • Genome-Wide Association Studies Candidate Gene to Dual Modifier of Nonalcoholic Steatohepatitis and Atherosclerosis. JACC. Basic to translational science Miller, C. L., Leeper, N. J. 2016; 1 (7): 680–83

    Abstract

    Non-alcoholic steatohepatitis (NASH) is a common disease involving chronic accumulation of fat and inflammation in the liver, often leading to advanced fibrosis, cirrhosis and cancer. It is known that NASH shares many features with atherosclerosis, however, there are still no effective therapeutics. In a recent study published in Nature, investigators demonstrate that mice lacking a high-density lipoprotein (HDL)-associated gene were surprisingly protected from both steatohepatitis and atherosclerosis through the stabilization of the liver X receptor (LXR). This work reveals a timely candidate target for two highly prevalent cardiovascular diseases.

    View details for PubMedID 28603781

  • The use of machine learning for the identification of peripheral artery disease and future mortality risk. Journal of vascular surgery Ross, E. G., Shah, N. H., Dalman, R. L., Nead, K. T., Cooke, J. P., Leeper, N. J. 2016; 64 (5): 1515-1522 e3

    Abstract

    A key aspect of the precision medicine effort is the development of informatics tools that can analyze and interpret "big data" sets in an automated and adaptive fashion while providing accurate and actionable clinical information. The aims of this study were to develop machine learning algorithms for the identification of disease and the prognostication of mortality risk and to determine whether such models perform better than classical statistical analyses.Focusing on peripheral artery disease (PAD), patient data were derived from a prospective, observational study of 1755 patients who presented for elective coronary angiography. We employed multiple supervised machine learning algorithms and used diverse clinical, demographic, imaging, and genomic information in a hypothesis-free manner to build models that could identify patients with PAD and predict future mortality. Comparison was made to standard stepwise linear regression models.Our machine-learned models outperformed stepwise logistic regression models both for the identification of patients with PAD (area under the curve, 0.87 vs 0.76, respectively; P = .03) and for the prediction of future mortality (area under the curve, 0.76 vs 0.65, respectively; P = .10). Both machine-learned models were markedly better calibrated than the stepwise logistic regression models, thus providing more accurate disease and mortality risk estimates.Machine learning approaches can produce more accurate disease classification and prediction models. These tools may prove clinically useful for the automated identification of patients with highly morbid diseases for which aggressive risk factor management can improve outcomes.

    View details for DOI 10.1016/j.jvs.2016.04.026

    View details for PubMedID 27266594

    View details for PubMedCentralID PMC5079774

  • Influence of age on androgen deprivation therapy-associated Alzheimer's disease SCIENTIFIC REPORTS Nead, K. T., Gaskin, G., Chester, C., Swisher-McClure, S., Dudley, J. T., Leeper, N. J., Shah, N. H. 2016; 6

    Abstract

    We recently found an association between androgen deprivation therapy (ADT) and Alzheimer's disease. As Alzheimer's disease is a disease of advanced age, we hypothesize that older individuals on ADT may be at greatest risk. We conducted a retrospective multi-institutional analysis among 16,888 individuals with prostate cancer using an informatics approach. We tested the effect of ADT on Alzheimer's disease using Kaplan-Meier age stratified analyses in a propensity score matched cohort. We found a lower cumulative probability of remaining Alzheimer's disease-free between non-ADT users age ≥70 versus those age <70 years (p < 0.001) and between ADT versus non-ADT users ≥70 years (p = 0.034). The 5-year probability of developing Alzheimer's disease was 2.9%, 1.9% and 0.5% among ADT users ≥70, non-ADT users ≥70 and individuals <70 years, respectively. Compared to younger individuals older men on ADT may have the greatest absolute Alzheimer's disease risk. Future work should investigate the ADT Alzheimer's disease association in advanced age populations given the greater potential clinical impact.

    View details for DOI 10.1038/srep35695

    View details for Web of Science ID 000385588200002

    View details for PubMedID 27752112

    View details for PubMedCentralID PMC5067668

  • Association Between Androgen Deprivation Therapy and Risk of Dementia. JAMA oncology Nead, K. T., Gaskin, G., Chester, C., Swisher-McClure, S., Leeper, N. J., Shah, N. H. 2016

    Abstract

    A growing body of evidence supports a link between androgen deprivation therapy (ADT) and cognitive dysfunction, including Alzheimer disease. However, it is currently unknown whether ADT may contribute to the risk of dementia more broadly.To use an informatics approach to examine the association of ADT as a treatment for prostate cancer with the subsequent development of dementia (eg, senile dementia, vascular dementia, frontotemporal dementia, and Alzheimer dementia).In this cohort study, a text-processing method was used to analyze electronic medical record data from an academic medical center from 1994 to 2013, with a median follow-up of 3.4 years (interquartile range, 1.0-7.2 years). We identified 9455 individuals with prostate cancer who were 18 years or older at diagnosis with data recorded in the electronic health record and follow-up after diagnosis. We excluded 183 patients with a previous diagnosis of dementia. Our final cohort comprised 9272 individuals with prostate cancer, including 1826 men (19.7%) who received ADT.We tested the effect of ADT on the risk of dementia using propensity score-matched Cox proportional hazards regression models and Kaplan-Meier survival analysis.Among 9272 men with prostate cancer (mean [SD] age, 66.9 [10.9] years; 5450 [58.8%] white), there was a statistically significant association between use of ADT and risk of dementia (hazard ratio, 2.17; 95% CI, 1.58-2.99; P < .001). In sensitivity analyses, results were similar when excluding patients with Alzheimer disease (hazard ratio, 2.32; 95% CI, 1.73-3.12; P < .001). The absolute increased risk of developing dementia among those who received ADT was 4.4% at 5 years (7.9% among those who received ADT vs 3.5% in those who did not receive ADT). Analyses stratified by duration of ADT found that individuals with at least 12 months of ADT use had the greatest absolute increased risk of dementia (hazard ratio, 2.36; 95% CI, 1.64-3.38; P < .001). Kaplan-Meier analysis demonstrated that ADT users 70 years or older had the lowest cumulative probability of remaining dementia free (log-rank P < .001).Androgen deprivation therapy in the treatment of prostate cancer may be associated with an increased risk of dementia. This finding should be further evaluated in prospective studies.

    View details for DOI 10.1001/jamaoncol.2016.3662

    View details for PubMedID 27737437

  • The Promise and Challenge of Induced Pluripotent Stem Cells for Cardiovascular Applications. JACC. Basic to translational science Youssef, A. A., Ross, E. G., Bolli, R., Pepine, C. J., Leeper, N. J., Yang, P. C. 2016; 1 (6): 510-523

    Abstract

    The recent discovery of human-induced pluripotent stem cells (iPSCs) has revolutionized the field of stem cells. iPSCs have demonstrated that biological development is not an irreversible process and that mature adult somatic cells can be induced to become pluripotent. This breakthrough is projected to advance our current understanding of many disease processes and revolutionize the approach to effective therapeutics. Despite the great promise of iPSCs, many translational challenges still remain. In this article, we review the basic concept of induction of pluripotency as a novel approach to understand cardiac regeneration, cardiovascular disease modeling and drug discovery. We critically reflect on the current results of preclinical and clinical studies using iPSCs for these applications with appropriate emphasis on the challenges facing clinical translation.

    View details for DOI 10.1016/j.jacbts.2016.06.010

    View details for PubMedID 28580434

  • The role of necroptosis in atherosclerotic disease. JACC. Basic to translational science Leeper, N. J. 2016; 1 (6): 548–50

    Abstract

    It is now known that cells don't always die by apoptosis, but can also undergo a process known as programmed cell necrosis, or necroptosis. In a study recently published in Science Advances, investigators reported that this pro-inflammatory process is active in human atherosclerosis, may promote growth of the necrotic core, and may serve as a novel molecular imaging and translational therapeutic target. These findings represent a major step in our goal to reduce coronary disease and stroke.

    View details for PubMedID 28480338

  • Use of Predictive Analytics for the Identification of Latent Vascular Disease and Future Adverse Cardiac Events Ross, E. G., Shah, N., Dalman, R. L., Nead, K., Leeper, N. J. MOSBY-ELSEVIER. 2016: 28S–29S
  • Statin Intensity or Achieved LDL? Practice-based Evidence for the Evaluation of New Cholesterol Treatment Guidelines PLOS ONE Ross, E. G., Shah, N., Leeper, N. 2016; 11 (5)

    Abstract

    The recently updated American College of Cardiology/American Heart Association cholesterol treatment guidelines outline a paradigm shift in the approach to cardiovascular risk reduction. One major change included a recommendation that practitioners prescribe fixed dose statin regimens rather than focus on specific LDL targets. The goal of this study was to determine whether achieved LDL or statin intensity was more strongly associated with major adverse cardiac events (MACE) using practice-based data from electronic health records (EHR).We analyzed the EHR data of more than 40,000 adult patients on statin therapy between 1995 and 2013. Demographic and clinical variables were extracted from coded data and unstructured clinical text. To account for treatment selection bias we performed propensity score stratification as well as 1:1 propensity score matched analyses. Conditional Cox proportional hazards modeling was used to identify variables associated with MACE.We identified 7,373 adults with complete data whose cholesterol appeared to be actively managed. In a stratified propensity score analysis of the entire cohort over 3.3 years of follow-up, achieved LDL was a significant predictor of MACE outcome (Hazard Ratio 1.1; 95% confidence interval, 1.05-1.2; P < 0.0004), while statin intensity was not. In a 1:1 propensity score matched analysis performed to more aggressively control for covariate balance between treatment groups, achieved LDL remained significantly associated with MACE (HR 1.3; 95% CI, 1.03-1.7; P = 0.03) while treatment intensity again was not a significant predictor.Using EHR data we found that on-treatment achieved LDL level was a significant predictor of MACE. Statin intensity alone was not associated with outcomes. These findings imply that despite recent guidelines, achieved LDL levels are clinically important and LDL titration strategies warrant further investigation in clinical trials.

    View details for DOI 10.1371/journal.pone.0154952

    View details for Web of Science ID 000376882500009

    View details for PubMedID 27227451

    View details for PubMedCentralID PMC4881915

  • Androgen Deprivation Therapy and Future Alzheimer's Disease Risk. Journal of clinical oncology Nead, K. T., Gaskin, G., Chester, C., Swisher-McClure, S., Dudley, J. T., Leeper, N. J., Shah, N. H. 2016; 34 (6): 566-571

    Abstract

    To test the association of androgen deprivation therapy (ADT) in the treatment of prostate cancer with subsequent Alzheimer's disease risk.We used a previously validated and implemented text-processing pipeline to analyze electronic medical record data in a retrospective cohort of patients at Stanford University and Mt. Sinai hospitals. Specifically, we extracted International Classification of Diseases-9th revision diagnosis and Current Procedural Terminology codes, medication lists, and positive-present mentions of drug and disease concepts from all clinical notes. We then tested the effect of ADT on risk of Alzheimer's disease using 1:5 propensity score-matched and traditional multivariable-adjusted Cox proportional hazards models. The duration of ADT use was also tested for association with Alzheimer's disease risk.There were 16,888 individuals with prostate cancer meeting all inclusion and exclusion criteria, with 2,397 (14.2%) receiving ADT during a median follow-up period of 2.7 years (interquartile range, 1.0-5.4 years). Propensity score-matched analysis (hazard ratio, 1.88; 95% CI, 1.10 to 3.20; P = .021) and traditional multivariable-adjusted Cox regression analysis (hazard ratio, 1.66; 95% CI, 1.05 to 2.64; P = .031) both supported a statistically significant association between ADT use and Alzheimer's disease risk. We also observed a statistically significant increased risk of Alzheimer's disease with increasing duration of ADT (P = .016).Our results support an association between the use of ADT in the treatment of prostate cancer and an increased risk of Alzheimer's disease in a general population cohort. This study demonstrates the utility of novel methods to analyze electronic medical record data to generate practice-based evidence.

    View details for DOI 10.1200/JCO.2015.63.6266

    View details for PubMedID 26644522

  • Reply. Gastroenterology Shah, N. H., Cooke, J. P., Leeper, N. J. 2016; 150 (2): 528-?

    View details for DOI 10.1053/j.gastro.2015.12.017

    View details for PubMedID 26721609

  • Proton pump inhibitors and vascular function: A prospective cross-over pilot study VASCULAR MEDICINE Ghebremariam, Y. T., Cooke, J. P., Khan, F., Thakker, R. N., Chang, P., Shah, N. H., Nead, K. T., Leeper, N. J. 2015; 20 (4): 309-316

    Abstract

    Proton pump inhibitors (PPIs) are commonly used drugs for the treatment of gastric reflux. Recent retrospective cohorts and large database studies have raised concern that the use of PPIs is associated with increased cardiovascular (CV) risk. However, there is no prospective clinical study evaluating whether the use of PPIs directly causes CV harm. We conducted a controlled, open-label, cross-over pilot study among 21 adults aged 18 and older who are healthy (n=11) or have established clinical cardiovascular disease (n=10). Study subjects were assigned to receive a PPI (Prevacid; 30 mg) or a placebo pill once daily for 4 weeks. After a 2-week washout period, participants were crossed over to receive the alternate treatment for the ensuing 4 weeks. Subjects underwent evaluation of vascular function (by the EndoPAT technique) and had plasma levels of asymmetric dimethylarginine (ADMA, an endogenous inhibitor of endothelial function previously implicated in PPI-mediated risk) measured prior to and after each treatment interval. We observed a marginal inverse correlation between the EndoPAT score and plasma levels of ADMA (r = -0.364). Subjects experienced a greater worsening in plasma ADMA levels while on PPI than on placebo, and this trend was more pronounced amongst those subjects with a history of vascular disease. However, these trends did not reach statistical significance, and PPI use was also not associated with an impairment in flow-mediated vasodilation during the course of this study. In conclusion, in this open-label, cross-over pilot study conducted among healthy subjects and coronary disease patients, PPI use did not significantly influence vascular endothelial function. Larger, long-term and blinded trials are needed to mechanistically explain the correlation between PPI use and adverse clinical outcomes, which has recently been reported in retrospective cohort studies.

    View details for DOI 10.1177/1358863X14568444

    View details for Web of Science ID 000359414300001

    View details for PubMedID 25835348

    View details for PubMedCentralID PMC4572842

  • Text-mining methods applied to clinical records support an association between androgen deprivation therapy and subsequent cardiometabolic disease Nead, K. T., Gaskin, G. L., Chester, C., Shah, N. H., Leeper, N. J. AMER ASSOC CANCER RESEARCH. 2015