title: Androgens regulate MMPs and the cellular processes of intimal hyperplasia.
abstract: BACKGROUND
  Testosterone deficiency has been associated with an increased risk of vascular disease. Matrix metalloproteinases (MMPs) have been implicated in vascular remodeling. Our group has demonstrated an association between female hormones and MMP-modulated intimal hyperplasia. In the present study, we investigated testosterone in the modulation of MMPs and the cellular processes of intimal hyperplasia.
  
  
  METHODS
  Male vascular smooth muscle cells (VSMCs) were treated with a range of testosterone or dihydrotestosterone (DHT) concentrations (0.3-3000 nM). MMPs were assayed using quantitative polymerase chain reaction, Western blot analysis, and zymography. VSMC migration and proliferation were assayed using Boyden chamber and MTT assays.
  
  
  RESULTS
  MT1-MMP gene expression was not affected by low DHT exposure but was downregulated at high levels (3000 nM = 85% ± 3%). TIMP-2 gene expression was downregulated at low DHT exposure (0.3 nM = 82% ± 4%, 3.0 nM = 82% ± 1%) but was not affected at high levels. MMP-2 enzymatic activity was increased at low DHT exposure (3.0 nM = 110% ± 4%) and decreased below basal levels at high doses (300 nM = 91% ± 7%, 3000 nM = 77% ± 8%). High concentrations of DHT decreased VSMC migration (3.0 nM = 72% ± 9%, 30 nM = 50% ± 6%, 300 nM = 47% ± 5%, 3000 nM = 53% ± 6%). Testosterone also decreased migration but had less effect. The highest tested concentration of DHT and testosterone decreased the basal VSMC proliferation (3000 nM = 87% ± 3% and 87% ± 4% respectively).
  
  
  CONCLUSIONS
  The DHT levels differentially affected the expression of regulatory isoforms responsible for the activation and inhibition of MMP-2, leading to an inverse relationship among the DHT levels, MMP-2 activity, and VSMC migration. In vivo studies will be used to examine testosterone deficiency and supplementation in MMP-modulated intimal hyperplasia in animal models of vascular disease. These studies are needed as a prerequisite to determining whether testosterone replacement in testosterone-deficient men should be evaluated for attenuation of atherosclerosis.
authors.affiliation: Department of Surgery, University of Tennessee Graduate School of Medicine, Knoxville, Tennessee 37920, USA.
authors.forename: Deidra J H
authors.initials: DJ
authors.lastname: Mountain
authors.forename: Brian M
authors.initials: BM
authors.lastname: Freeman
authors.forename: Stacy S
authors.initials: SS
authors.lastname: Kirkpatrick
authors.forename: John W
authors.initials: JW
authors.lastname: Beddies
authors.forename: Joshua D
authors.initials: JD
authors.lastname: Arnold
authors.forename: Michael B
authors.initials: MB
authors.lastname: Freeman
authors.forename: Mitchell H
authors.initials: MH
authors.lastname: Goldman
authors.forename: Scott L
authors.initials: SL
authors.lastname: Stevens
authors.forename: Frederick A
authors.initials: FA
authors.lastname: Klein
authors.forename: Oscar H
authors.initials: OH
authors.lastname: Grandas
mesh_terms: D000728:Androgens / Q000378:metabolism* / Q000494:pharmacology; D002465:Cell Movement / Q000502:physiology; D049109:Cell Proliferation; D002478:Cells, Cultured; D024141:Collagen Type IV / Q000378:metabolism; D013196:Dihydrotestosterone / Q000378:metabolism* / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004789:Enzyme Activation / Q000187:drug effects; D006801:Humans; D006965:Hyperplasia / Q000473:pathology; D008297:Male; D053511:Matrix Metalloproteinase 14 / Q000235:genetics / Q000378:metabolism*; D020778:Matrix Metalloproteinase 2 / Q000235:genetics / Q000378:metabolism*; D008875:Middle Aged; D009131:Muscle, Smooth, Vascular / Q000166:cytology* / Q000187:drug effects / Q000201:enzymology; D012333:RNA, Messenger / Q000378:metabolism; D019716:Tissue Inhibitor of Metalloproteinase-2 / Q000235:genetics / Q000378:metabolism; D017539:Tunica Intima / Q000378:metabolism / Q000473:pathology; D014652:Vascular Diseases / Q000378:metabolism* / Q000473:pathology
chemical_list: D000728:Androgens; D024141:Collagen Type IV; D012333:RNA, Messenger; C560823:TIMP2 protein, human; D013196:Dihydrotestosterone; D019716:Tissue Inhibitor of Metalloproteinase-2; C522361:MMP2 protein, human; D020778:Matrix Metalloproteinase 2; C507086:MMP14 protein, human; D053511:Matrix Metalloproteinase 14
keywords: Extracellular matrix; Intimal hyperplasia; Matrix metalloproteinase; Migration; Proliferation; Testosterone; Vascular smooth muscle cells