title: Simvastatin pretreatment enhances ischemia-induced neovascularization and blood flow recovery in streptozotocin-treated mice.
abstract: OBJECTIVE
  In contrast to statins, ezetimibe belongs to a new class of cholesterol-lowering agent not known to mediate pleiotropic effects. Here we investigate whether ezetimibe or simvastatin can help recover blood flow and reduce tissue damage after hindlimb ischemia surgery in diabetic mice.
  
  
  METHODS
  Diabetic mice were created by intraperitoneal streptozotocin injection in male FVB/NJ mice. All diabetic mice were subsequently divided into three groups: diabetic control, diabetic with simvastatin (0.2 mg/kg), and diabetic with ezetimibe (0.1 mg/kg). All experimental mice received hindlimb ischemia surgery after 2 weeks of drug treatment. Circulating endothelial progenitor cell number was determined by flow cytometry (Sca-1+/C-kit+/Flk-1+) in peripheral blood.
  
  
  RESULTS
  In comparison to the mice in the diabetic control group (n = 6), wild-type mice (n = 6) and diabetic mice that received simvastatin (n = 6) had significantly increased ischemic/nonischemic limb blood perfusion ratio, higher capillary density (P < .05, respectively), and reduced ischemic limb damage (diabetic control, 80%; diabetic with simvastatin, 40%; diabetic with ezetimibe, 80%). However, these proangiogenic effects were not observed in diabetic mice that had been treated with ezetimibe. In addition, the number of ischemia-triggered endothelial progenitor cells in peripheral blood was significantly enhanced in the wild-type mice and in the diabetic mice being treated with simvastatin, but not in those being treated with ezetimibe, after ischemic surgery. Endothelial nitric oxide synthase activity as determined by acetylcholine-stimulated vasorelaxation recovered notably in diabetic mice that were treated with simvastatin but was not improved by ezetimibe (n = 6, each group). Moreover, simvastatin led to a significant upregulation of endothelial nitric oxide synthase phosphorylation; vascular endothelial growth factor protein levels in ischemic tissues were also increased. By contrast, administration of ezetimibe did not produce these effects.
  
  
  CONCLUSIONS
  Simvastatin helped recover blood flow and reduce tissue damage in ischemic hindlimbs and also promoted new vessel formation in streptozotocin-treated mice, whereas ezetimibe did not. These results may help explain why statins and ezetimibe decrease cholesterol levels, whereas their pleiotropic effects on vasoprotective functions independent of low-density lipoprotein cholesterol lowering are different.
authors.affiliation: Institute of Clinical Medicine, National Yang-Ming University, Taipei, Taiwan; Cardiovascular Research Center, National Yang-Ming University, Taipei, Taiwan; Division of Cardiology, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan. Electronic address: huangbs@vghtpe.gov.tw.
authors.forename: Po-Hsun
authors.initials: PH
authors.lastname: Huang
authors.affiliation: Institute of Clinical Medicine, National Yang-Ming University, Taipei, Taiwan.
authors.forename: Jian-You
authors.initials: JY
authors.lastname: Chen
authors.affiliation: Institute of Clinical Medicine, National Yang-Ming University, Taipei, Taiwan.
authors.forename: Chi-Yu
authors.initials: CY
authors.lastname: Chen
authors.affiliation: Cardiovascular Research Center, National Yang-Ming University, Taipei, Taiwan; Division of Cardiology, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan; Department of Medical Research, Taipei Veterans General Hospital, Taipei, Taiwan; Institute and Department of Pharmacology, National Yang-Ming University, Taipei, Taiwan.
authors.forename: Jaw-Wen
authors.initials: JW
authors.lastname: Chen
authors.affiliation: Institute of Clinical Medicine, National Yang-Ming University, Taipei, Taiwan; Cardiovascular Research Center, National Yang-Ming University, Taipei, Taiwan; Division of Cardiology, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan; Department of Medical Research, Taipei Veterans General Hospital, Taipei, Taiwan; Taipei Medical University, Taipei, Taiwan.
authors.forename: Shing-Jong
authors.initials: SJ
authors.lastname: Lin
authors.affiliation: Institute of Clinical Medicine, National Yang-Ming University, Taipei, Taiwan; Cardiovascular Research Center, National Yang-Ming University, Taipei, Taiwan; Division of Cardiovascular Surgery, Department of Surgery, Taipei Veterans General Hospital, Taipei, Taiwan.
authors.forename: Chun-Che
authors.initials: CC
authors.lastname: Shih
mesh_terms: D000818:Animals; D001783:Blood Flow Velocity; D003097:Collateral Circulation; D003921:Diabetes Mellitus, Experimental / Q000139:chemically induced / Q000150:complications*; D003925:Diabetic Angiopathies / Q000188:drug therapy* / Q000209:etiology / Q000378:metabolism / Q000503:physiopathology; D066026:Endothelial Progenitor Cells / Q000187:drug effects / Q000378:metabolism; D000069438:Ezetimibe / Q000494:pharmacology; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors / Q000494:pharmacology*; D007511:Ischemia / Q000188:drug therapy* / Q000209:etiology / Q000378:metabolism / Q000503:physiopathology; D008297:Male; D051379:Mice; D018919:Neovascularization, Physiologic / Q000187:drug effects*; D052250:Nitric Oxide Synthase Type III / Q000378:metabolism; D010766:Phosphorylation; D020127:Recovery of Function; D012039:Regional Blood Flow; D019821:Simvastatin / Q000494:pharmacology*; D013311:Streptozocin; D013997:Time Factors; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism; D014664:Vasodilation / Q000187:drug effects
chemical_list: D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors; D042461:Vascular Endothelial Growth Factor A; C467480:vascular endothelial growth factor A, mouse; D013311:Streptozocin; D019821:Simvastatin; D052250:Nitric Oxide Synthase Type III; C496316:Nos3 protein, rat; D000069438:Ezetimibe