Effects of purified fish oil on platelet lipids and function in diabetic women

Purified fish oil (MaxEpa, 10 g/day) treatment for six weeks increased consistently the content of eicosapentaenoic (20:5, n-3), docosapentaenoic (22:5, n-3) and docosahexaenoic acid (22:6, n-3) and decreased that of arachidonic acid (20:4, n-6) and other n-6 polyunsaturated C-20 fatty acids (PUFA) of platelets both in insulin dependent diabetic (IDDM) (n = 13) and healthy women (n = 7), but it had no effect on the number and aggregation of platelets or on plasma beta-thromboglobulin. Serum TxB2, produced by diabetic platelets was reduced, but the urine 6-keto PGF1 alpha excretion, believed to reflect prostacyclin (PGI2) production was normal in the diabetics. During the MaxEpa treatment the response of thromboxane B2 (TxB2) release to ADP was decreased in platelet-rich plasma in the healthy subjects. However, in diabetics the fish oil treatment resulted in increased TxB2 formation from exogenous arachidonic acid. The results demonstrate the dependence of platelets fatty acid composition on dietary sources and suggest that at least in the diabetic platelets the diminished arachidonic acid content could be compensated by an activation of enzymes of thromboxane B2 pathway.