PMID: 2504863Aug 1, 1989Paper

Eicosanoid metabolism in cholesterol-enriched arterial smooth muscle cells: reduced arachidonate release with concomitant decrease in cyclooxygenase products.

Journal of Lipid Research
K B Pomerantz, D P Hajjar

Abstract

A biochemical correlation between vascular cholesterol metabolism and eicosanoid biosynthesis has not been fully elucidated. To assess the effects of cholesteryl ester (CE) accretion on eicosanoid synthesis, we studied eicosanoid metabolism in cultured rabbit aortic smooth muscle cells (SMC) following lipid-enrichment by incubation with cationized LDL (cLDL). SMC exposed to cLDL synthesized 50% less immunoreactive 6-keto-PGF1 alpha than untreated cells when exposed to the calcium ionophore, A-23187. In addition, cLDL-treatment reduced arachidonate acid (AA)-induced prostacyclin (PGI2) production sevenfold. Components of cLDL decreased eicosanoid biosynthesis in the following rank-order: linoleate greater than cholesterol greater than apo-cLDL. Lipid-enriched cells incorporated amounts of [1-14C]AA into phosphatidylcholine and phosphatidylethanolamine equal to control cells, but subsequent exposure to ionophore released significantly less radioactivity as free arachidonate (AA), with proportionally less conversion to eicosanoids. Ionophore released equivalent amounts of AA from all phospholipids, suggesting specificity for uptake, but not release of AA by cellular phospholipases. Cells enriched in CE had an eightfold decrease in...Continue Reading

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