Comparison of oxidized low-density lipoprotein toxicity on EA.hy 926 cells and human vein endothelial cells: influence of antioxidant systems

Abstract.

We compared the susceptibility to oxidized LDL cytotoxicity of primary human umbilical vein endothelial cells (HUVEC) and EA.hy 926 cells. EA.hy 926 endothelial cells were more susceptible than HUVEC. To determine the basis of this difference, we evaluated the enzymatic antioxidant machinery in the two cell types. The antioxidant enzyme activities of superoxide dismutase, catalase and glutathione peroxidase were significantly lower in EA.hy cells than in HUVEC: 54%, 71% and 8% of the HUVEC enzyme activities respectively. Pre-incubation of the EA.hy 926 endothelial cells with glutathione peroxidase (100 IU/ml) inhibited the cytotoxic effect of oxidized LDL. Superoxide dismutase (300 or 600 IU/ml) and catalase (300 or 600 IU/ml) had no effect. Compared to HUVEC, the higher susceptibility of EA.hy 926 cells to oxidized LDL–induced injury may be associated with lower antioxidant defences, in particular with lower glutathione peroxidase activity which is known to eliminate lipid hydroperoxides and thereby to prevent the formation of damaging peroxyl radical intermediates.