Modification of human platelet fatty acid composition induced by lecithin-rich fat emulsions with different triacylglycero cores and phospholipic surfaces

Abstract

Platelets are the major cells that produce eicosanoids such as prostaglandin (PG) from membranes unsaturated fatty acids (PUFA) : EPA and arachidonic acid (AA). AA-derived PGs are provasoconstrictory and proaggregatory whereas EPA-derived PGs yields the opposite properties. EPA and other n-3 PUFA; DHA, replace AA in membranes and turn cell to be antiatherogenic and antithrombogenic which consequently prevent the body from stroke and cardiovascular disease. In our previous experiment, we disigned lecithin-rich fat emulsions (LRFE) with high proportion of DHA in phospholipid moiety. This novel emulsion was able to supply n-3 PUFA effectively to red blood cells. The purpose of the present study was whether our four LRFE’s with lecithins derived from fish meal (FM-LRFE), soya (SY-LRFE), soya cored with fish oil (SL-FOFE) and egg yolk which was commercially available (20% Lipofundin), restructured n-3/n-6 PUFA ratio of platelet membranes. Platelet concentrates (PC) were prepared and provided for the experiment from Thai Red Cross. They were incubated for 1 h at 22 °C with each freshly prepared LRFE at the phospholipid (PL) concentrations of 0, 100, 300, 600 mg/dl incubation mixture and platelet concentration of approximately 1.86x10⁹ cells/ml. The increased ratio of n-3/n-6 PUFA of platelets after incubation with FM-LRFE at 600 mg PL/dl autologous plasma was 1.8 times lower than the mixture with plasma free. In addition, all altered fatty acids on platelets were maintained in plasma-free condition for at least 5 h. Incubation with FM-LRFE, the increase of n-3/n-6 PUFA ratio was dose dependent (Y=0.16+3E-04 X ,p<0.001). The ratio elevation appeared with much less extent under incubation condition with SY-LRFE (Y=0.143+3E-05X, p<0.005). The latter showed EPA and DHA decreased whereas major n-3 PUFA, alpha-linolenate (ALA), increased. Incubation with SL-FOFE demonstrated that n-3 PUFA in emulsion’s core provided trace effect to the fatty acid exchanges occurred on the surface. The 20% Lipofundin gave the least alteration of platelet fatty acids. In conclusion: platelet membranes’ PUFA profiles is able to be restructured as needed. FM-LRFE supplies n-3 PUFA whereas SY-LRFE provides n-6 PUFA to the platelet membranes. The higher n-3/n-6 PUFA ratio of platelet membranes is benefit for the production of antithrombogenic PG.