Eicosanoid balance at early stages of experimental atherosclerosis. Its relationship with plasma fibrinolytic activity and platelet aggregation.

We have studied generation of eicosanoids in blood vessels and platelets of rabbits in relation to platelet aggregation and plasma fibrinolytic activity at early stages of experimental atherosclerosis. A level of lipid peroxides in plasma augmented progressively from the 2-nd to 12-th week of atherogenic diet. In parallel, platelets generated more TXA2 and 12-HETE while in blood vessels a gradual reduction of prostacyclin formation was observed. Reduction in generation of PGI2 was accompanied by steady formation of PGE2. In the second week of the diet a slight decrease appeared of aggregatory response while later aggregability of platelets was increased. At first, plasma fibrinolytic activity was decreased, but it significantly augmented after 12 weeks of the diet. The above data indicate that changes of arachidonic acid metabolism in platelets and blood vessels appear at a very early stage of atherosclerosis and they influence platelet function and plasma fibrinolytic activity.