title: Decreased expression of vitamin D receptors in neointimal lesions following coronary artery angioplasty in atherosclerotic swine.
abstract: BACKGROUND
  Inflammatory cytokines, such as TNF-α, play a key role in the pathogenesis of occlusive vascular diseases. Activation of vitamin D receptors (VDR) elicits both growth-inhibitory and anti-inflammatory effects. Here, we investigated the expression of TNF-α and VDR in post-angioplasty coronary artery neointimal lesions of hypercholesterolemic swine and examined the effect of vitamin D deficiency on the development of coronary restenosis. We also examined the effect of calcitriol on cell proliferation and effect of TNF-α on VDR activity and expression in porcine coronary artery smooth muscle cells (PCASMCs) in-vitro.
  
  
  RESULTS
  Expression of VDR and TNF-α and the effect of vitamin D deficiency in post-angioplasty coronary arteries were analyzed by immunohistochemistry and histomorphometry. Cell proliferation was examined by thymidine and BrdU incorporation assays in cultured PCASMCs. Effect of TNF-α-stimulation on the activity and expression of VDR was analyzed by luciferase assay, immunoblotting and immunocytochemistry. In-vivo, morphometric analysis of the tissues revealed typical lesions with significant neointimal proliferation. Histological evaluation showed expression of smooth muscle α-actin and significantly increased expression of TNF-α in neointimal lesions. Interestingly, there was significantly decreased expression of VDR in PCASMCs of neointimal region compared to normal media. Indeed, post-balloon angioplasty restenosis was significantly higher in vitamin D-deficient hypercholesterolemic swine compared to vitamin D-sufficient group. In-vitro, calcitriol inhibited both serum- and PDGF-BB-induced proliferation in PCASMCs and TNF-α-stimulation significantly decreased the expression and activity of VDR in PCASMCs.
  
  
  CONCLUSIONS
  These data suggest that significant downregulation of VDR in proliferating smooth muscle cells in neointimal lesions could be due to atherogenic cytokines, including TNF-α. Vitamin D deficiency potentiates the development of coronary restenosis. Calcitriol has anti-proliferative properties in PCASMCs and these actions are mediated through VDR. This could be a potential mechanism for uncontrolled growth of neointimal cells in injured arteries leading to restenosis.
authors.affiliation: Department of Biomedical Sciences and Center for Clinical and Translational Science, Creighton University School of Medicine, Omaha, Nebraska, United States of America.
authors.forename: Gaurav K
authors.initials: GK
authors.lastname: Gupta
authors.forename: Tanupriya
authors.initials: T
authors.lastname: Agrawal
authors.forename: Michael G
authors.initials: MG
authors.lastname: Del Core
authors.forename: William J
authors.initials: WJ
authors.lastname: Hunter
authors.forename: Devendra K
authors.initials: DK
authors.lastname: Agrawal
mesh_terms: D015906:Angioplasty, Balloon, Coronary / Q000009:adverse effects*; D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D050197:Atherosclerosis / Q000097:blood / Q000473:pathology / Q000628:therapy*; D000077214:Becaplermin; D002117:Calcitriol / Q000494:pharmacology; D049109:Cell Proliferation / Q000187:drug effects; D023903:Coronary Restenosis / Q000097:blood / Q000209:etiology / Q000473:pathology; D003331:Coronary Vessels / Q000187:drug effects / Q000473:pathology* / Q000601:surgery*; D004195:Disease Models, Animal; D055785:Gene Knockdown Techniques; D006965:Hyperplasia; D008055:Lipids / Q000097:blood; D032389:Myocytes, Smooth Muscle / Q000187:drug effects / Q000473:pathology; D058426:Neointima / Q000097:blood / Q000209:etiology* / Q000473:pathology*; D020574:Proto-Oncogene Proteins c-sis / Q000494:pharmacology; D034741:RNA, Small Interfering / Q000378:metabolism; D018167:Receptors, Calcitriol / Q000235:genetics / Q000378:metabolism*; D034421:Sus scrofa / Q000601:surgery; D014158:Transcription, Genetic / Q000187:drug effects; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology; D014807:Vitamin D / Q000378:metabolism
chemical_list: D008055:Lipids; D020574:Proto-Oncogene Proteins c-sis; D034741:RNA, Small Interfering; D018167:Receptors, Calcitriol; D014409:Tumor Necrosis Factor-alpha; D014807:Vitamin D; D000077214:Becaplermin; D002117:Calcitriol