title: Only two-week smoking cessation improves platelet aggregability and intraplatelet redox imbalance of long-term smokers.
abstract: OBJECTIVE
  We investigated whether and how soon smoking cessation ameliorates the smoking-induced intracellular oxidative stress and platelet aggregability in long-term smokers.
  
  
  BACKGROUND
  Smoking is a major risk factor of atherothrombosis. Smoking cessation reduces cardiac events. However, the underlying mechanisms of the beneficial effects remain to be elucidated.
  
  
  METHODS
  Twenty-seven male long-term smokers were divided into two groups. Group A (n = 14) quit smoking for four weeks whereas group B (n = 13) resumed smoking two weeks after quitting. Smoking status was monitored by measurement of urinary cotinine. Using gel-filtered platelets, agonist (adenosine diphosphate and collagen)-induced platelet aggregation, platelet-derived nitric oxide (PDNO), intraplatelet nitrotyrosine production, intraplatelet levels of the reduced form of glutathione (GSH) and its oxidized form (GSSG), and urinary 8-hydroxy-2'-deoxyguanosine (8-OHdG) and urinary 8-iso-prostaglandin F(2alpha) (8-iso-PGF(2alpha)), as markers of systemic oxidative stress, were measured. The baseline measurements were similar between the two groups.
  
  
  RESULTS
  Smoking cessation quickly reduced agonist-induced platelet aggregations, intraplatelet nitrotyrosine level, and urinary productions of 8-OHdG and 8-iso-PGF(2alpha) by two weeks in both groups. In group A, they were maintained at the low levels until four weeks, whereas they were reversed by resmoking in group B; PDNO release and intraplatelet GSH/GSSG ratio were time-dependently increased by smoking cessation but reversed by resmoking.
  
  
  CONCLUSIONS
  The present findings are the first demonstration that only two weeks of smoking cessation can ameliorate the enhanced platelet aggregability and intraplatelet redox imbalance in long-term smokers, possibly by decreasing oxidative stress. Our findings may strengthen the motivation for smokers to quit smoking.
authors.affiliation: Department of Internal Medicine III, Kurume University School of Medicine, Kurume, Japan.
authors.forename: Hirohiko
authors.initials: H
authors.lastname: Morita
authors.forename: Hisao
authors.initials: H
authors.lastname: Ikeda
authors.forename: Nobuya
authors.initials: N
authors.lastname: Haramaki
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Eguchi
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Imaizumi
mesh_terms: D000328:Adult; D001792:Blood Platelets / Q000378:metabolism*; D006801:Humans; D008297:Male; D010084:Oxidation-Reduction; D010974:Platelet Aggregation; D012907:Smoking / Q000378:metabolism*; D016540:Smoking Cessation / Q000706:statistics & numerical data; D013997:Time Factors