The effect of high density lipoprotein subfractions on endothelial eicosanoid secretion

Epidemiological, clinical, and experimental studies have demonstrated that high density lipproteins (HDL) are protective against atherosclerosis, However, the respective influence of two main HDL subfractions (HDL2 and HDL3) on atherosclerosis process is not yet clear. The present study was designed to determine, which HDL subfraction was antiatherogenic in terms of eicosanoid release by human umbilical vein endothelial cells (HUVEC). Endothelial cells were incubated for 4 hours with HDL2 or HDL3 and prostaglandins 6-keto-PGF1 alpha, thromboxane B-2 and prostaglandin E-2 were measured by RIA in culture supernatant, HDL, has a dose dependent stimulatory effect on 6-keto-PGF(1 alpha) release without stimulatory effect on thromboxane B-2 secretion. The 6-keto-PGF(1 alpha)/thromboxane B-2 ratio increased progressively from 1.65 to 4.65 for 0.39 to 6.25 mg HDL protein/ml. The pattern of prostanoid secretion under influence of HDL; showed a predominant response in 6-keto-PGF(1 alpha), and TxB(2) release. As regards PGE(2), both HDL subfractions stimulated considerably secretion of this prostanoid in a dose dependent manner, In terms of PGI(2)/TxA(2) balance the better antiatherogenic effect was observed with HDL, subfraction. (C) 1998 Elsevier Science Ltd.