Relationship between Fatty-Acid Composition of Platelets and Platelet Aggregation in Rat and Man

Male rats fed a diet rich in butter or stearic acid presented a marked predisposition to endotoxin-initiated thrombosis. This was preceded by hypercholesterolemia, hypercoagulability, and an increased susceptibility of platelets to thrombin-induced aggregation. In contrast to this, feeding of corn oil or linoleic or oleic acids did not result in such marked changes in the blood or in severe thrombosis. Gas-liquid chromatographic analysis of total lipids of platelet and plasma indicated that the thrombogenic fat or fatty acid resulted in a highly significant increase, mostly in the platelets, of the ratio of saturated + monounsaturated to polyunsaturated fatty acids (S+M)/P. In patients who had suffered a myocardial infarction as compared with men without risk factors for coronary heart disease, an increase in the (S+M)/P in plasma and platelets was also observed. Among 17 active middle-aged businessmen, the five who presented signs of coronary heart disease also showed the highest susceptibility to thrombin-induced aggregation, but not to ADP or collagen. In these 17 subjects, the results of the thrombin aggregation could be correlated with the platelet (S+M)/P, but not with the plasma or platelet cholesterol. In both the rat and man, a high thrombotic tendency may be associated with a platelet hypersusceptibility to thrombin which, in turn, is related to changes in fatty-acid composition.