title: Ascorbic acid improves impaired venous and arterial endothelium-dependent dilation in smokers.
abstract: OBJECTIVE
  To compare the acute effects of ascorbic acid on vasodilation of veins and arteries in vivo.
  
  
  METHODS
  Twenty-six healthy non-smokers and 23 healthy moderate smokers were recruited in this study. The dorsal hand vein compliance technique and flow-mediated dilation were used. Dose-response curves to bradykinin and sodium nitroprusside were constructed to test the endothelium-dependent and -independent relaxation before and after acute infusion of ascorbic acid.
  
  
  RESULTS
  Smokers had an impaired venodilation with bradykinin compared with non-smokers (68.3%+/-13.2% vs 93.7%+/-20.1%, respectively; P<0.05). Ascorbic acid administration in the dorsal hand vein significantly increased the venodilation with bradykinin in smokers (68.3%+/-13.2% vs 89.5%+/-6.3% before and after infusion, respectively; P<0.05) but not in non-smokers (93.7%+/-20.1% vs 86.4%+/-12.4% before and after infusion, respectively). Similarly, the arterial response in smokers had an impaired endothelium-dependent dilation compared with that in non-smokers (8.8%+/-2.7% vs 15.2%+/-2.3%, respectively; P<0.05) and ascorbic acid restored this response in smokers (8.8%+/-2.7% vs 18.7%+/-6.5% before and after infusion, respectively; P<0.05), but no difference was seen in non-smokers (15.2%+/-2.3% vs 14.0%+/-4.4% before and after infusion, respectively). The endothelium-independent dilation did not differ in both the groups studied. No important hemodynamic change was detected using the Portapress device.
  
  
  CONCLUSIONS
  Smokers had impaired endothelium-dependent vasodilation responsiveness in both arterial and venous systems. Ascorbic acid restores this responsiveness in smokers.
authors.affiliation: Cardiovascular Pharmacology and Cardiology, Clinical Hospital of Campinas and Faculty of Medical Sciences, State University of Campinas, 13081-970, Campinas, Sao Paulo, Brazil.
authors.forename: Marcio Goncalves
authors.initials: MG
authors.lastname: de Sousa
authors.forename: Juan Carlos
authors.initials: JC
authors.lastname: Yugar-Toledo
authors.forename: Marcelo
authors.initials: M
authors.lastname: Rubira
authors.forename: Silvia Elaine
authors.initials: SE
authors.lastname: Ferreira-Melo
authors.forename: Rodrigo
authors.initials: R
authors.lastname: Plentz
authors.forename: Deise
authors.initials: D
authors.lastname: Barbieri
authors.forename: Fernanda
authors.initials: F
authors.lastname: Consolim-Colombo
authors.forename: Maria Claudia
authors.initials: MC
authors.lastname: Irigoyen
authors.forename: Heitor
authors.initials: H
authors.lastname: Moreno
mesh_terms: D000328:Adult; D001205:Ascorbic Acid / Q000494:pharmacology*; D001916:Brachial Artery / Q000503:physiopathology; D001920:Bradykinin / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004730:Endothelium, Vascular / Q000187:drug effects*; D005260:Female; D006225:Hand / Q000098:blood supply; D006801:Humans; D008297:Male; D009599:Nitroprusside / Q000494:pharmacology; D012907:Smoking / Q000503:physiopathology*; D014664:Vasodilation / Q000187:drug effects*; D014680:Veins / Q000503:physiopathology
chemical_list: D009599:Nitroprusside; D001205:Ascorbic Acid; D001920:Bradykinin