Overexpression of Human Superoxide Dismutase Inhibits Oxidation of Low-Density Lipoprotein by Endothelial Cells

Oxidation of LDL in the subendothelial space has been proposed to play a key role in atherosclerosis. Endothelial cells produce superoxide anions (O (2) sup [center dot] -) and oxidize LDL in vitro; however, the role of O2 sup [center dot] - in endothelial cell-induced LDL oxidation is unclear. Incubation of human LDL (200 [micro sign]g/mL) with bovine aortic endothelial cells (BAECs) for 18 hours resulted in a 4-fold increase in LDL oxidation compared with cell-free incubation (22.5 +/- 1.1 versus 6.3 +/- 0.2 [mean +/- SEM] nmol malondialdehyde/mg LDL protein, respectively; P