Handbook of Vitamin C Research

Vitamin C in the Treatment of Endothelial Dysfunction 347Vitamin C Supplementation in SmokersAcute effects of intra-arterial infusion of the antioxidant vitamin C (18 mg/min) in 10control subjects and 10 chronic smokers have been investigated by Heitzer and coworkers[45] by assessing forearm blood flow responses to the endothelium-dependent vasodilatoracetylcholine (7.5, 15, 30, and 60 micrograms/min) and the endothelium-independentvasodilator sodium nitroprusside (1, 3, and 10 micrograms/min) using venous occlusionplethysmography. In chronic smokers, forearm blood flow responses to acetylcholine wasimproved by concomitant intraarterial infusion of vitamin C, while the vasodilator responsesto sodium nitroprusside was not affected. No effect was seen in the control group.Antoniades and coworkers [46] investigated the effect of single and combinedantioxidant treatment with vitamins C and E on endothelial function and plasma levels ofplasminogen activator inhibitor (PAI-1), von Willebrand factor (vWF), tissue plasminogenactivator (tPA) and factor VII (fVII), in 41 smokers. Forearm blood flow was measured usingvenous occlusion strain-gauge plethysmography in response to reactive hyperemia(endothelium-dependent) or to sublingual nitroglycerin administration (endotheliumindependent).Subjects were randomly divided into 4 groups receiving vitamin C 2g/day(group A), vitamin C 2g/day plus vitamin E 400 IU/day (group B), vitamin C 2g/day plusvitamin E 800 IU/day (group C) or no antioxidants (controls, group D), for 4 weeks. Aftertreatment, endothelium-dependent vasodilatation was increased only in groups B (p