Prolonged Plasma Clotting Time and Decreased Fibrinolysis after Long Term Treatment with α-Tocopherol

Abstract

SummaryBlood platelet function, blood clotting and fibrinolysis were studied in a group of 9 male post myocardial infarction patients once a week for 5 consecutive weeks after which α-tocopherol 300 mg/day was given. The group was again investigated after 2, 6, 18, 44 and 64 weeks of α-tocopherol treatment. After 18, 44 and 64 weeks of treatment a highly significant prolongation of the plasma clotting time was observed. On the basis of the analyses made it is concluded that the prolongation is probably due to a decreased platelet factor 3 activity. The ability to increase fibrinolytic activity after stasis of the arm is reduced after long term α-tocopherol treatment. There were no changes in the number of platelets, platelet adhesiveness, factor II-VII-X activity, factor VIII, fibrinogen, antithrombin III, α1-antitrypsin, α2-macroglobulin, total anti-fibrinolytic activity or plasminogen. Our hypothesis to explain the results is that α-tocopherol influences on the cell membranes of the platelets and the endothelial cells and thus causes a reduced release of platelet factor 3 and activators of fibrinolysis. This is in line with many other observations indicating that α-tocopherol is of importance for the cell membrane function.