Tumor necrosis factor enhances low density lipoprotein oxidative modification by monocytes and endothelial cells

The effect of tumor necrosis factor on the oxidative modification of LDL by U937 human monocytes or murine endothelial cells was studied by determination of the lipid peroxidation product content and the electrophoretic mobility of the particle. In the range of concentrations from 2.5 to 10 ng/ml, the cytokine induced a dose-dependent increase in cellular-induced oxidation of LDL. This effect was accompanied by a stimulation of LDL degradation by J774 macrophage-like cells. Concurrently, the TNF-treated cells secreted superoxide anion with a higher rate. Since LDL oxidation is believed to be an important feature in the formation of the atherosclerotic plaque, the described effects of TNF might be of importance in long-term exposure to this cytokine during inflammation.