A study of the putative anti-atherogenic mechanisms of Vitamin E and Vitamin C in subjects at coronary risk

The effects of the antioxidant vitamins E and C on monocyte adhesion, platelet adhesion and platelet aggregation has been examined in vitro on cells isolated from healthy volunteers, and ex vivo using cells isolated from patients at coronary risk.;Pre-incubation of platelets with vitamin E inhibited platelet aggregation (p<0.05), platelet adhesion (p<0.05) and reduced platelet membrane microviscosity (p<0.05). Pre-incubation of platelets with vitamin C, however, failed to significantly affect platelet adhesion. Pre-incubation of monocytes with vitamin E inhibited their subsequent adhesion to plastic (p<0.05), whilst pre-incubation of the endothelial cells with vitamin E also significantly reduced subsequent monocyte adhesion (p<0.05).;Twenty eight patients, with a diagnosis of primary hypercholesterolaemia received placebo (soybean oil) for six weeks, followed by vitamin E at a dose of 400 IU per day. Following six weeks of vitamin E supplementation thrombin induced platelet aggregation was significantly inhibited (p<0.01), while monocyte adhesion remained unaffected.;In fifty six untreated elderly hypertensive and normotensive volunteers, monocyte adhesion to collagen coated microwells was significantly correlated with daytime pulse pressure (r = 0.38, p<0.01). Forty of these subjects were randomly allocated to a crossover trial of vitamin C 500 mg daily versus placebo each for 3 months. Vitamin C supplementation significantly reduced daytime systolic blood pressure (p<0.05) and man arterial blood pressure (p<0.05) in the elderly hypertensive subjects. Platelet adhesion to collagen coated (p<0.05) and tissue culture plastic microwells (p<0.01) was also reduced in the elderly normotensive subjects.;Eighty seven patients undergoing routine coronary angioplasty were randomly allocated to receive either placebo (n = 42) or vitamin E (n = 45) at a dose of 800 IU per day prior to the angioplasty procedure and for at least six months after. Neither placebo nor vitamin E supplementation did prevent the rise in plasma levels of soluble P-selectin following angioplasty (p<0.05).