RAPID ONSET INHIBITION OF AFRICAN GREEN MONKEY PLATELETS AFTER INTRAVENOUS ADMINISTRATION OF A MARINE OIL LIPID EMULSION

Abstract

To evaluate how rapidly and to what extent a lipid emulsion rich in n-3 fatty acids could alter platelet function, six male juvenile African Green Monkeys (4-6 kg) were given a 6-hour IV continuous infusion of a 10% marine oil (MO) lipid emulsion (5 ml /kg/hr). Following a 21-day washout period, the same monkeys were given a similar infusion of a 10% soybean oil (SO) lipid emulsion (TRAVAMULSION®, Travenol Labs). Blood samples were collected pre-infusion, and at 6, 12, and 24 hours following initiation of infusion, upon which the following were measured: whole blood platelet aggregation and thromboxane B2 release following collagen activation, platelet count, and platelet total fatty acid composition (pre-infusion and 24 hrs only). Lipid Emulsion Fatty Acid Composition: mg/ml(% total F.A.) Both emulsions elicited comparable reductions in both platelet aggregation and thromboxane B2 release immediately following infusion (6 hr). Platelet aggregation response after MO was significantly less than that after SO at both 12 (pc.001) and 24 hrs (p<.001), and thromboxane B2 release was significantly less after MO vs SO at 24 hrs (p<.03). Platelet counts remained unchanged after both treatments. Platelet total fatty acid analyses revealed significant increases in % total F.A. for C20:5 [1.87(pre) vs 4.79(24hr); p<.005] and for C22:6 [1.09(pre) vs 3.15(24hr); p<.001] and significant decreases in % total F.A. for C18:2 [8.94(pre) vs 7.77(24hr); p<.05] and C20:4 [22.6(pre) vs 19.6(24hr) p<.05], following infusion of M0. Following infusion of SO, the % total F.A. change in C22:6 was the only one of significance [0.85(pre) vs 1.25(24hr); p<.05]. This was attributed to the C18:3 in the SO lipid emulsion. Whereas the IV infusion of an n-6 rich lipid emulsion has little effect upon platelet fatty acid composition and function, similar administration of an n-3 rich lipid emulsion markedly reduces platelet function and effects a significant increase in the n-3/n-6 fatty acid ratio of the platelets.