title: Sirolimus and everolimus induce endothelial cellular senescence via sirtuin 1 down-regulation: therapeutic implication of cilostazol after drug-eluting stent implantation.
abstract: OBJECTIVE
  The aim of this study was to compare the effects of paclitaxel, sirolimus, and everolimus on the senescent phenotype in human endothelial cells, and to further investigate possible involvement of mammalian sirtuin 1 (Sirt1) down-regulation as a mechanism.
  
  
  BACKGROUND
  Endothelial cell senescence may play a role in impaired re-endothelialization after drug-eluting stent (DES) implantation. Recently, the down-regulation of Sirt1 has been shown to mediate oxidative stress-induced endothelial senescence.
  
  
  METHODS
  Senescent human umbilical vein endothelial cells (HUVEC) were judged by senescence-associated beta-galactosidase assay (SA-betagal), morphological appearance, and plasminogen activator inhibitor (PAI)-1.
  
  
  RESULTS
  Treatment with paclitaxel, sirolimus, and everolimus significantly caused a senescent phenotype and PAI-1 up-regulation, associated with a decrease in endothelial nitric oxide synthase (eNOS) and Sirt1 expression. Overexpression of Sirt1 or Sirt1 activation reversed the sirolimus- or everolimus-induced senescent phenotype. Interestingly, paclitaxel-induced senescence was not suppressed by Sirt1 overexpression, suggesting the existence of a different mechanism. Cilostazol markedly inhibited the sirolimus- or everolimus-induced senescent phenotype (sirolimus or everolimus [2.5 nmol/l]; 49.2% or 53.0% SA-betagal positive vs. only 13.6% or 14.6% with cilostazol [100 micromol/l]) and PAI-1 up-regulation, but had no influence on the effects of paclitaxel. Finally, aspirin significantly blunted sirolimus- or everolimus-induced senescence, but neither ticlopidine nor clopidogrel had any effects.
  
  
  CONCLUSIONS
  Sirolimus and everolimus induce endothelial senescence involving down-regulation of Sirt1. In contrast, the development of endothelial senescence by paclitaxel involves a Sirt1-independent pathway. Because sirolimus and everolimus are involved in Sirt1 modulation, cilostazol rescues HUVEC from sirolimus- or everolimus-induced senescence. These results may have therapeutic implications in the clinical sequelae after DES implantation.
authors.affiliation: Department of Geriatric Medicine, Graduate School of Medicine, University of Tokyo, Tokyo, Japan.
authors.forename: Hidetaka
authors.initials: H
authors.lastname: Ota
authors.forename: Masato
authors.initials: M
authors.lastname: Eto
authors.forename: Junya
authors.initials: J
authors.lastname: Ako
authors.forename: Sumito
authors.initials: S
authors.lastname: Ogawa
authors.forename: Katsuya
authors.initials: K
authors.lastname: Iijima
authors.forename: Masahiro
authors.initials: M
authors.lastname: Akishita
authors.forename: Yasuyoshi
authors.initials: Y
authors.lastname: Ouchi
mesh_terms: D001241:Aspirin / Q000494:pharmacology; D016922:Cellular Senescence / Q000187:drug effects; D000077407:Cilostazol; D000077144:Clopidogrel; D015536:Down-Regulation / Q000187:drug effects; D054855:Drug-Eluting Stents; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects*; D000068338:Everolimus; D006801:Humans; D007166:Immunosuppressive Agents / Q000494:pharmacology*; D052250:Nitric Oxide Synthase Type III / Q000187:drug effects; D018384:Oxidative Stress; D017239:Paclitaxel / Q000494:pharmacology; D017395:Plasminogen Activator Inhibitor 1 / Q000378:metabolism; D010975:Platelet Aggregation Inhibitors / Q000494:pharmacology; D020123:Sirolimus / Q000031:analogs & derivatives / Q000494:pharmacology*; D056564:Sirtuin 1; D037761:Sirtuins / Q000037:antagonists & inhibitors* / Q000187:drug effects / Q000235:genetics; D013777:Tetrazoles / Q000494:pharmacology*; D013988:Ticlopidine / Q000031:analogs & derivatives / Q000494:pharmacology; D014665:Vasodilator Agents / Q000494:pharmacology*
chemical_list: D007166:Immunosuppressive Agents; D017395:Plasminogen Activator Inhibitor 1; D010975:Platelet Aggregation Inhibitors; D013777:Tetrazoles; D014665:Vasodilator Agents; D000068338:Everolimus; D000077144:Clopidogrel; C496314:NOS3 protein, human; D052250:Nitric Oxide Synthase Type III; C447939:SIRT1 protein, human; D056564:Sirtuin 1; D037761:Sirtuins; D000077407:Cilostazol; D013988:Ticlopidine; D017239:Paclitaxel; D001241:Aspirin; D020123:Sirolimus