Plasmalogens and oxidative stress: evidence against a major role of plasmalogens in protection against the superoxide anion radical.

Although ether-linked phospholipids have been known to be constituents of biological membranes for a long time, their physiological function has remained an enigma through the years. Inspired by the suggestion of Zoeller and coworkers that plasmalogens, which are specific types of ether-linked phospholipids characterized by the occurrence of an alpha, beta-unsaturated ether bond at the sn-1 position, are involved in the protection of cells against reactive oxygen species, we studied reactive oxygen species metabolism in cultured human skin fibroblasts. Menadione was used as intracellular generator of reactive oxygen species and cytochrome c as extracellular indicator for the production of reactive oxygen species. The finding that identical results were obtained in control and plasmalogen-deficient fibroblasts leads us to conclude that plasmalogens do not play a major role in protection against reactive oxygen species.