[Inflammation cytokines and peroxidation of low density lipoproteins (LDL)]

The effect of the inflammatory cytokins TNF-alpha, oncostatin M and interleukine 1 (IL1) on low density lipoprotein (LDL) oxidative modification have been studied on UNA endothelial cells or U937 monocytes in culture, by measuring the end products of lipid peroxydation (TBARS) and the relative electrophoretic mobility of the particle. TNF-alpha as well as oncostatin M stimulated in a dose-dependent manner the LDL peroxidation induced either by endothelial cells or U937 monocytes, and induced an increase in the uptake of modified LDL by J774 macrophages. Both TNF-alpha and oncostatin enhanced the superoxide anion production by endothelial cells or monocytes. In contrast, IL1 did not influence LDL cellular oxidation, but increased cholesterol esterification by stimulating the Acyl coenzyme A: cholesterol-0-acyltransferase (ACAT) activity of J774 macrophages. If IL1 acts on cholesteryl ester deposition by a mechanism differing from those of TNF-alpha or oncostatin M, all the studied cytokins may increase cholesteryl ester deposition. These results point at the potential promoting action of inflammatory processes in the progress of atherogenesis.