Effect of Vitamin E Supplementation on Platelet Thromboxane A₂ Production in Type I Diabetic Patients: Double-Blind Crossover Trial

Vitamin E deficiency is associated with increased platelet aggregation, which can be normalized through vitamin E supplementation. In diabetes, increased platelet thromboxane A₂ (TXA₂) production is correlated with decreased platelet vitamin E content. We therefore investigated the effect of 400 mg DL-α-tocopherol acetate daily for 4 wk on ADP- and collagen-induced platelet aggregation and platelet TXA₂ production in 22 type I (insulin-dependent) diabetic patients without macroangiopathy and with no or only minimal microangiopathy by a double-blind placebo-controlled crossover study. Platelet aggregation was induced in platelet-rich plasma by two or three different concentrations of ADP and collagen. TXA₂ was measured by the stable spontaneous breakdown product thromboxane B₂ by a specific radioimmunoassay. Whereas metabolic control remained unchanged during the study period, platelet TXA₂ production was significantly (P < .05 and P < .01) reduced at each ADP concentration and at two of three collagen concentrations. Because increased TXA₂ production of diabetic platelets is thought to play an important pathogenetic role in diabetic angiopathy, we conclude that vitamin E treatment could be beneficial with respect to platelet–vessel-wall interaction and thus might be promising for the prevention of diabetic angiopathy.