Unsaturated fatty acids and platelet aggregation: in vitro study.

The effects of several cis and two trans fatty acids (elaidic and linoelaidic acids) - sodium salt and also in free acid form - on ADP-induced platelet aggregation were studied. The effects of the cis and trans fatty acids (sod. salt) on collagen-induced aggregation were also examined. Besides, the effects of several cis fatty acids, including dihomo-gamma-linolenic acid, on arachidonic acid induced aggregation were examined. The results indicate that unsaturated fatty acids inhibit platelet aggregation induced by ADP and collagen. The unsaturated fatty acids, however, with most blood samples did not show any antiaggregation effect on arachidonic acid-induced aggregation. While showing an antiaggregation effect on collagen-induced aggregation and failing to do so on arachidonic acid-induced aggregation, this difference in the behaviour of the unsaturated fatty acids in the two aggregations can be explained on the basis of binding of exogenous test fatty acids to plasma proteins. The mechanism(s) by which unsaturated fatty acids, in general, may exert their antiaggregation effect is discussed.