Phospholipid hydroperoxides are significantly less toxic to cultured endothelial cells than fatty acid hydroperoxides.

Optically active hydroperoxides of phospholipids including phosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol, and phosphatidic acid were synthesized, and their cytotoxicity to cultured bovine pulmonary artery endothelial cells was examined. Phospholipid hydroperoxides were readily incorporated into cells during the incubation in a medium containing each hydroperoxide. Phospholipids with a linoleic acid hydroperoxide residue showed no toxicity, whereas phosphatidylcholine with an arachidonic acid hydroperoxide residue was somewhat toxic. When hydroperoxyarachidonoylphosphatidylcholine was reduced to hydroxyarachidonoylphosphatidylcholine, the reduction product was found to have no toxicity. It appears that phospholipid hydroperoxides, unless converted into more reactive compounds, are significantly less toxic to endothelial cells than fatty acid hydroperoxides.