title: Cyclooxygenase-1 mediated platelet reactivity in young male smokers.
abstract: BACKGROUND
  The purpose of this study is to investigate the acute and chronic effects of cigarette smoking on cyclooxygenase- 1(COX-1)-mediated platelet reactivity among cigarette smokers.
  
  
  METHODS
  The levels of collagen-induced platelet aggregation, platelet COX-1 activity, and expressions were compared between smokers and age-matched nonsmokers. In smokers, the acute effects of cigarette smoking were assessed by repeating these measurements an hour after smoking.
  
  
  RESULTS
  Twenty-five smokers and age-matched nonsmokers (all men; mean age, 29 years) were studied. Collagen-induced platelet aggregation and plasma/urinary thromboxane B2 (TXB2) and 11-dehydroxythromboxane B2 levels were higher in cigarette smokers compared to nonsmokers. Greater expression of platelet COX-1 was observed in smokers than in nonsmokers. Among smokers, collagen-induced platelet aggregation correlated positively with platelet volume and circulating nicotine and cotinine concentrations. The levels of plasma/urinary TXB2 were significantly increased an hour after cigarette smoking.
  
  
  CONCLUSIONS
  Cigarette smoking aggravates COX-1-mediated platelet reactivity in young, otherwise healthy, smoking men.
authors.affiliation: 1Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.
authors.forename: Wai Mun
authors.initials: WM
authors.lastname: Loke
authors.forename: Karen Lam Mok
authors.initials: KL
authors.lastname: Sing
authors.forename: Chung-Yung J
authors.initials: CY
authors.lastname: Lee
authors.forename: Wan Ling
authors.initials: WL
authors.lastname: Chong
authors.forename: Soh Eng
authors.initials: SE
authors.lastname: Chew
authors.forename: Huiwen
authors.initials: H
authors.lastname: Huang
authors.forename: Woan Foon
authors.initials: WF
authors.lastname: Looi
authors.forename: Amy M L
authors.initials: AM
authors.lastname: Quek
authors.forename: Erle C H
authors.initials: EC
authors.lastname: Lim
authors.forename: Raymond Chee Seong
authors.initials: RC
authors.lastname: Seet
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000097:blood / Q000652:urine; D001792:Blood Platelets / Q000378:metabolism*; D051545:Cyclooxygenase 1 / Q000097:blood*; D006801:Humans; D008297:Male; D010974:Platelet Aggregation; D012907:Smoking / Q000097:blood* / Q000652:urine; D013929:Thromboxane B2 / Q000097:blood / Q000652:urine
chemical_list: D015415:Biomarkers; D013929:Thromboxane B2; D051545:Cyclooxygenase 1; C496511:PTGS1 protein, human