PLATELET INHIBITORY FUNCTIONS OF AORTIC ENDOTHELIAL-CELLS - EFFECTS OF EICOSAPENTAENOIC AND DOCOSAHEXAENOIC ACIDS

The endothelial cell platelet inhibitory potential was assessed direct ly by measuring the platelet inhibition induced by platelet interactio n with the cultured aortic endothelial cells. The prostacyclin content of the platelet suspensions after interaction was also quantified. We found that prostacyclin production accounted for the overall platelet inhibitory potential of the aortic cells since: (a) endothelial cells incubated with aspirin, which did not produce prostacyclin, did not i nhibit platelets; (b) the prostacyclin content of platelet suspensions after interaction with endothelial cells correlated with the extent o f the platelet inhibition; (c) such a platelet inhibition was reproduc ed by adding synthetic prostacylin in amount equivalent to that produc ed by endothelial cells during the interaction. Eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids incorporated into endothelial phospho lipids, decreased the ability of the cells to produce prostacyclin and to inhibit platelets, DHA being less effective than EPA.