Author + information
- Received October 19, 2008
- Revision received December 17, 2008
- Accepted January 27, 2009
- Published online June 16, 2009.
- Hidetaka Ota, MD, PhD,
- Masato Eto, MD, PhD,
- Junya Ako, MD, PhD,
- Sumito Ogawa, MD, PhD,
- Katsuya Iijima, MD, PhD,
- Masahiro Akishita, MD, PhD and
- Yasuyoshi Ouchi, MD, PhD⁎ ()
- ↵⁎Reprint requests and correspondence:
Dr. Yasuyoshi Ouchi, Department of Geriatric Medicine, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655, Japan
Objectives 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 β-galactosidase assay (SA-βgal), 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-βgal positive vs. only 13.6% or 14.6% with cilostazol [100 μmol/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.
Supported by Grants-in-Aid for Scientific Research from the Ministry of Education, Science, Culture, and Sports of Japan (20249041, 18590801, 18890056)
- Received October 19, 2008.
- Revision received December 17, 2008.
- Accepted January 27, 2009.
- American College of Cardiology Foundation