Vitamin E and stabilization of membrane lipid organization in red blood cells with peroxidative damage

The phospholipids distribution across red cell membrane bilayer is asymmetrical. Phosphatidylcholine (PC) and sphingomyelin (SM) are predominantly present in the outer, and phosphatidylserine (PS) and phosphatidylethanolamine (PE) are predominantly present on the cytoplasmic side of the red cell membrane. The present study reports the effect of fatty acid peroxidation on the organization of PS and PE in human red cells using a nonpermeable Bee Venom phospholipase-A2 which specifically hydrolyzes outer bilayer lipids. Lipid peroxidation in the red cell membranes was accomplished by exposing cells to hydrogen peroxide. This treatment resulted in a significant movement of PS and PE from inner bilayer to outer bilayer, which had a highly positive correlation with the concentration of malonyldialdehyde generated in the red cells. Antioxidant vitamin E abolished the effects of peroxide treatment on fatty acid peroxidation and red cell membrane lipid organization. Thus, lipid peroxidative damage can disturb organization of phospholipids in the membrane bilayer of human red cells.