Relationship between platelet membrane lipid compositions and platelet aggregability in alcoholic liver disease.

We studied the relationship between changes in platelet aggregability and platelet membrane lipid in alcoholic liver disease. The maximal rate of ADP-induced platelet aggregation was significantly increased in the alcoholic liver disease group than in the control group. No significant difference was observed in the maximal rate of collagen-induced platelet aggregation. However, a lag time required for the start of platelet aggregation was significantly shortened in the alcoholic liver disease group, indicating increased platelet aggregability. Results of the platelet aggregation test suggested that alcoholic liver disease patients have their platelet aggregation affected by the abnormality of prostaglandin metabolism. The alcoholic liver disease group was further divided into two subgroups: the hyperaggregation group and the unchanged aggregation group. Both free cholesterol and phospholipid in the platelet membrane were significantly increased in the alcoholic liver disease group. In phospholipid compositions, phosphatidylserine plus phosphatidylinositol were significantly decreased in the alcoholic liver disease group, whereas a significant decrease in phosphatidylserine plus phosphatidylinositol was observed in the hyperaggregation group of alcoholic liver disease. Analysis of fatty acid compositions of platelet membrane showed significantly decreased palmitic acid in the alcoholic group. There was no significant change of arachidonic acid, which directly affects platelet aggregation. Eicosapentaenoic acid significantly decreased in the alcoholic liver disease group, but there was no difference in docosahexaenoic acid. Meanwhile, the thrombogenic index, calculated from the fatty acids of platelet membrane, showed no difference between the alcoholic liver disease group and the control group. However, the thrombogenic index was significantly increased in the hyperaggregation group than in the unchanged aggregation group. These data suggested that platelet aggregation is affected by not only a change in arachidonic acid, but also changes in fatty acid compositions of the platelet membrane.