title: Microvascular reactivity in response to smoking and oral antioxidants in humans.
abstract: OBJECTIVE
  To investigate whether a daily intake of a moderate dose of antioxidants modifies the microcirculatory response to smoking, assuming a major influence of oxidative stress on microcirculation.
  
  
  METHODS
  The microvascular response to smoking was assessed in individual capillaries by capillaroscopy before and after two weeks of treatment with oral antioxidants.
  
  
  RESULTS
  Smoking prolonged time to peak (TtP) capillary blood flow velocity in all subjects. When the subjects were pre-treated with ascorbate, TtP was comparable to baseline values of untreated subjects. No significant effect of vitamin E was observed either before or after smoking. Capillary blood flow velocity increased after treatment with ascorbate as well as after vitamin E. However, significant reductions in velocity were still observed in response to smoking even after subjects consumed ascorbate and vitamin E (p<0.0004 and p<0.000008 respectively).
  
  
  CONCLUSIONS
  This study focused on individual capillaries, and confirms that smoking has a very pronounced, direct and reproducible microvascular effect possible to demonstrate in vivo in human capillaries. Moderate intake of the antioxidant ascorbate clearly mitigated the effects induced by smoking. TtP after smoking in subjects treated with ascorbate was similar to that observed in untreated subjects before smoking a cigarette. Thus, oxidative stress could be assumed to play a role in the effects of smoking on microcirculation.
authors.affiliation: Department of Clinical Sciences, Danderyd Hospital, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Peter
authors.initials: P
authors.lastname: Henriksson
authors.forename: Ulf
authors.initials: U
authors.lastname: Diczfalusy
authors.forename: Anna
authors.initials: A
authors.lastname: Freyschuss
mesh_terms: D000284:Administration, Oral; D000328:Adult; D000975:Antioxidants / Q000008:administration & dosage*; D001205:Ascorbic Acid / Q000008:administration & dosage*; D001783:Blood Flow Velocity / Q000187:drug effects; D002196:Capillaries / Q000503:physiopathology; D005260:Female; D006801:Humans; D008297:Male; D008833:Microcirculation / Q000187:drug effects*; D020678:Microscopic Angioscopy / Q000379:methods; D008875:Middle Aged; D018384:Oxidative Stress / Q000187:drug effects*; D012907:Smoking / Q000503:physiopathology*; D014810:Vitamin E / Q000008:administration & dosage*
chemical_list: D000975:Antioxidants; D014810:Vitamin E; D001205:Ascorbic Acid