title: Long-term nicotine exposure induces dysfunction of mouse endothelial progenitor cells.
abstract: Endothelial progenitor cells (EPCs) have an important role in maintaining endothelial homeostasis. Previous studies reported that smoking has detrimental effects on EPCs; however, recent studies revealed that short-term nicotine exposure may benefit EPCs. As most smokers are exposed to nicotine over an extended time period, the present study aimed to investigate the long-term effects of nicotine on EPCs. Mice were administered nicotine orally for 1, 3 or 6 months. The mice exposed to nicotine for 1 month demonstrated increased EPC counts and telomerase activity and reduced cell senescence compared with control mice, consistent with previous reports. However, long-term nicotine exposure resulted in opposing effects on EPCs, causing decreased counts, functional impairment and reduced telomerase activity. Furthermore, the effects of nicotine exposure were correlated with changes in sirtuins type 1 (SIRT1) protein expression. The current study indicated that long-term nicotine exposure induces dysfunction and senescence of EPCs, which may be associated with impairment of telomerase activity through SIRT1 downregulation. The present results emphasize the necessity of smoking cessation to prevent dysfunction of EPCs.
authors.affiliation: Department of Cardiology, 305 Hospital of the People's Liberation Army, Beijing 100017, P.R. China.
authors.forename: Wei
authors.initials: W
authors.lastname: Li
authors.affiliation: Department of Cardiology, 305 Hospital of the People's Liberation Army, Beijing 100017, P.R. China.
authors.forename: Da-Yong
authors.initials: DY
authors.lastname: Du
authors.affiliation: Department of Cardiology, 305 Hospital of the People's Liberation Army, Beijing 100017, P.R. China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Department of Cardiology, 305 Hospital of the People's Liberation Army, Beijing 100017, P.R. China.
authors.forename: Feng
authors.initials: F
authors.lastname: Jiang
authors.affiliation: Department of Cardiology, 305 Hospital of the People's Liberation Army, Beijing 100017, P.R. China.
authors.forename: Pan
authors.initials: P
authors.lastname: Zhang
authors.affiliation: Department of Cardiology, 305 Hospital of the People's Liberation Army, Beijing 100017, P.R. China.
authors.forename: Yun-Tian
authors.initials: YT
authors.lastname: Li
keywords: SIRT1; endothelial progenitor cells; nicotine; senescence; telomerase