Chronic exposure of cultured bovine endothelial cells to oxidized LDL abolishes prostacyclin release

Abstract

We investigated the effect of chronic exposure (3 days) with low-density lipoprotein (LDL) and oxidized (Ox)-LDL on the unstimulated and stimulated formation of prostacyclin (6-keto-prostagIandin [PG]F1α) and total inositol phosphates (IPs) by cultured bovine aortic endothelial cells. Neither basal nor bradykinin-stimulated (1 to 10 nmol/L) formation of 6-keto-PGF1α was affected by LDL, except at the highest concentration of bradykinin tested (100 nmol/L). In the presence of the antioxidants N-acetyl-L-cysteine (NAC, 10 μmol/L) or vitamin E (100 μmol/L), basal and bradykinin-stimulated formation of 6-keto-PGF1α was potentiated by 20 μg protein/mL of LDL. Ox-LDL decreased unstimulated formation of the eicosanoid from 3.1±0.2 pg/μg protein in control cells to 1.6±0.1 and 0.5±0.1 pg/μg protein after 3-day incubation with 5 and 20 μg protein/mL of Ox-LDL, respectively (P