Difference in susceptibility to injury by linoleic acid hydroperoxide between endothelial and smooth muscle cells of arteries.

Electron microscopic examination of the effect of linoleic acid hydroperoxide on cultured smooth muscle cells from human umbilical artery revealed that incubation of the cells with 5.0 nmol/ml (in terms of malondialdehyde) of the hydroperoxide for 3 h caused a decrease in the electron density of the mitochondrial matrix and that dilatation of the rough-surfaced endoplasmic reticulum occurred when the cells were incubated with 10 nmol/ml of the hydroperoxide. These concentrations are higher by one order of magnitude than those required for the same effects on cultured endothelial cells from human umbilical vein. A similar difference in susceptibility to injury by linoleic acid hydroperoxide was found between cultured endothelial and smooth muscle cells from fetal calf aorta. The effects of the hydroperoxide on the respiration of these cells paralleled the observed morphological changes.