Antiplatelts Activity of Vitamin E in Relation to Dose and Duration of Therapy

Abstract

           Vitamin E, having the well known antioxidant activity  through scavenging free radicals Ùˆ it occurs in several  isomeric forms , these isomers have relatively different functions . One of these actions is related to its ability to inhibit platelets aggregation and hence thrombosis. The present study included a total number of apparently healthy  62 males . 11of them served as standard group , treated  with 100 mg aspirin /day for more than one month . Another 31 subjects were randomly grouped into 5 groups that received different daily doses of α – tocopherol : 400 IU , 800 IU and 1200 IU for  2-6 months.The remainder ( 20 ) subjects served as  a control  group ( received no therapy ) . Platelets function was assessed based on measuring bleeding time and  Slide Platelets  Aggregation Time ( SPAT ) Meanwhile , thiobarbituric acid reactive substances  (TBARS) were measured as a marker for oxidative stress. The results showed that the commercially available vitamin E preparations  (α- tocopherol ) could exert anti-coagulant effect ,such effect is more dependant on duration of therapy , rather than dose related action .In addition to it’s antioxidant effect, which seems to be significantly correlated to it’s antiplatelets effect  ( r=0.994 ,p<0.05).Hence , long  term administration   of high doses of vitamin E  could be effective in decreasing the incidence of thrombosis ,which in turn depends on platelets function. Such effect might not affect bleeding time obviously , but it could reduce chances for platelets recruitment , which might represent an additional advantageous action for vitamin E  over other antioxidants.

Key Words :  Vitamin E  , α -  Tocopherol ,   Antiplatelets