title: Contribution of nicotine to acute endothelial dysfunction in long-term smokers.
abstract: OBJECTIVE
  The aim of this study was to determine whether nicotine, a constituent of cigarette smoke, contributes to acute endothelial dysfunction after smoking one cigarette.
  
  
  BACKGROUND
  Animal studies suggest that nicotine might cause an impairment of endothelium-dependent vasodilation via an increase in oxidative stress.
  
  
  METHODS
  Sixteen healthy smokers were entered into a randomized, observer-blinded crossover study comparing the effects of nicotine nasal spray (1-mg nicotine) and cigarette smoke (1-mg nicotine, 12 mg tar) on vascular reactivity in the brachial artery. Using high-resolution ultrasound, flow-mediated dilation (FMD) and endothelium-independent, nitroglycerin-induced dilation were assessed at baseline and 20 min after the administration of nicotine (spray or cigarette).
  
  
  RESULTS
  In response to similar increases in nicotine serum levels, FMD values declined from 10.2 +/- 4.4% to 6.7 +/- 4.0% after the spray (mean difference: -3.6 +/- 2.0%, 95% confidence interval: -4.6; -2.5, p < 0.0001) and from 9.4 +/- 3.8% to 4.3 +/- 2.8% after the cigarette (-5.1 +/- 2.6%, -6.5; -3.7, p < 0.0001). Nitroglycerin-induced dilation remained similar within both periods. Performing a period effect analysis of variance, a significant influence on FMD was found for the mode of administration (p = 0.017) and the baseline value (p = 0.021). The effect on FMD was more pronounced after the cigarette than after the spray (estimated average effect difference: 1.9% FMD). Oxidation parameters did not increase significantly after nicotine spray or tobacco exposure.
  
  
  CONCLUSIONS
  These results demonstrate that nicotine alone causes acute endothelial dysfunction, although to a lesser extent than smoking a cigarette of the same nicotine yield. However, the precise mechanisms by which nicotine leads to this altered vascular reactivity remain unclear.
authors.affiliation: Department of Cardiology, University of Vienna, Vienna, Austria. thomas.neunteufel@univie.ac.at
authors.forename: Thomas
authors.initials: T
authors.lastname: Neunteufl
authors.forename: Sandra
authors.initials: S
authors.lastname: Heher
authors.forename: Karam
authors.initials: K
authors.lastname: Kostner
authors.forename: Goran
authors.initials: G
authors.lastname: Mitulovic
authors.forename: Stephan
authors.initials: S
authors.lastname: Lehr
authors.forename: Gholamali
authors.initials: G
authors.lastname: Khoschsorur
authors.forename: Rainer W
authors.initials: RW
authors.lastname: Schmid
authors.forename: Gerald
authors.initials: G
authors.lastname: Maurer
authors.forename: Thomas
authors.initials: T
authors.lastname: Stefenelli
mesh_terms: D000328:Adult; D002851:Chromatography, High Pressure Liquid; D018592:Cross-Over Studies; D004730:Endothelium, Vascular / Q000187:drug effects*; D005260:Female; D006801:Humans; D008297:Male; D009538:Nicotine / Q000494:pharmacology*; D018384:Oxidative Stress / Q000502:physiology; D016037:Single-Blind Method; D012907:Smoking / Q000503:physiopathology*; D017392:Thiobarbituric Acid Reactive Substances; D014664:Vasodilation / Q000187:drug effects
chemical_list: D017392:Thiobarbituric Acid Reactive Substances; D009538:Nicotine