Ultrastructural Changes in Human Platelet During Fatty Acid Salt Aggregation

Abstract

We studied ultrastructural changes in platelet aggregation induced by fatty acid (FFA) salts. The platelets were used either directly in their original plasma or separated from plasma proteins by washing or filtration on 2 B Sepharose gel and suspended in a buffer solution with or without albumin.After fixation for electron microscopy the aggregating FF A salts appear as micellar structures or spherules of large size ressembling liposomes.During the first seconds of contact between the platelets and the FFA salts we observed the spreading of platelets on the surface of the structures formed, and the particles smaller than 1 μ were phagocytized. After a few minutes platelet release occurred followed by total degranulation of platelets during the formation of aggregates. After eight minutes the aggregates still contain FFA salts structures.These results confirm our earlier views that the mechanism of FFA salt induced aggregation differs from that of aggregation by other agents, and could be due to the micellar structure.