Vitamin E potentiates the antiplatelet activity of aspirin in collagen-stimulated platelets

Background and Objectives. The combination of vitamin E with aspirin is becoming an attractive therapeutic approach to prevent thrombotic vascular accidents. In this study we investigated the capacity of vitamin E (50 and 100 μM) to enhance the antiplatelet effect of aspirin. Design and Methods. The dose-response curves of platelet aggregation, dense body secretion, phospholipase C activation and calcium mobilization were measured in aspirin-treated platelets with and without added vitamin E (50 and 100 μM). The role of vitamin E in reducing platelet adhesion to collagen was also studied. Results. We demonstrated that, in platelets incubated with 100 μM vitamin E, collagen-concentration (μg/mL) able to induce 50% of the maximal platelet aggregation and of the calcium mobilization was higher than in controls (11.6 versus 3.8 and 21.3 versus 9.8, respectively). Furthermore, 50 μM vitamin E reduced platelet adhesion to collagen by about 80%. Interpretation and Conclusions. These data demonstrate that vitamin E can potentiate the antiplatelet activity of aspirin by inhibiting the early events of platelet activation pathways induced by collagen. This finding provides a rationale for combining aspirin and vitamin E to prevent thrombotic complications in atherosclerotic patients.