Vitamin C has no effect on endothelium-dependent vasomotion and acute endogenous fibrinolysis in healthy smokers

M Paola Pellegrini, David E Newby, Neil R Johnston, Simon Maxwell, David J Webb

Research output: Contribution to journalArticlepeer-review

Abstract

Blood flow and plasma fibrinolytic factors were measured on five occasions in both forearms of eight otherwise healthy male smokers during unilateral brachial artery infusion of the endothelium-dependent vasodilator, substance P (2 to 8 pmol/min), and the endothelium-independent vasodilator, sodium nitroprusside (2 to 8 microg/min). On the first occasion, intra-arterial vitamin C was co-infused at 25 mg/min. On subsequent occasions, subjects attended after 28 and 35 days treatment with oral vitamin C (1 g daily) or placebo in a double-blind randomized crossover design still smoking but with and without acute smoke inhalation (3 cigarettes over 30 minutes). Basal plasma ascorbate concentrations increased from 37 +/- 6 micromol/L to 105 +/- 11 micromol/L following oral vitamin C supplementation (P = 0.002). Substance P caused dose-dependent increases in forearm blood flow (P < 0.001, ANOVA) and t-PA release (P < 0.05, ANOVA) that was unaffected by acute recent smoke inhalation, intra-arterial vitamin C, or oral vitamin C administration (p = ns). Likewise there were no effects on sodium nitroprusside-induced vasodilatation (p = ns). Neither acute local intra-arterial nor prolonged oral vitamin C supplementation reverses smoking-related endothelial dysfunction and impaired endogenous t-PA release. We conclude that the adverse vascular actions of smoking are not principally mediated through oxidative stress.

Original languageEnglish
Pages (from-to)117-24
Number of pages8
JournalJournal of cardiovascular pharmacology
Volume44
Issue number1
Publication statusPublished - Jul 2004

Keywords / Materials (for Non-textual outputs)

  • Adult
  • Antioxidants
  • Ascorbic Acid
  • Blood Pressure
  • Cross-Over Studies
  • Double-Blind Method
  • Endothelium, Vascular
  • Fibrinolysis
  • Heart Rate
  • Humans
  • Male
  • Nitroprusside
  • Smoking
  • Substance P
  • Tissue Plasminogen Activator
  • Vasodilation
  • Vasodilator Agents

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