Lipid abnormalities and peroxidation of erythrocytes in nephrotic syndrome

Serum lipid abnormalities are a common feature of the nephrotic syndrome. It is suggested that this may influence the membrane lipid composition of red cells, which on the other hand may result in an abnormal sensitivity of red cells to lipid peroxidation. Therefore, lipids of plasma and red cell membranes from 7 patients with nephrotic syndrome and from 31 healthy control subjects were examined. In addition, the consequences for the hydrogen-peroxide-induced lipid peroxidation of red cells as an index for their capacity to compensate for oxidant stress was measured. All patients were anemic. Their red cells exhibited a significantly increased susceptibility to lipid peroxidation. Fatty acid analysis revealed a decreased proportion of linoleic acid in plasma and red cell membrane. The content of cholesterol in patients' red cell membranes was clearly diminished. It is shown that this abnormality was related to the enhanced sensitivity of their red cells for peroxidative stress. The present study shows that in addition to an impairment of red cells' antioxidant enzymes, abnormalities of the membrane lipid composition should be considered investigating the cause for an increased susceptibility to lipid peroxidation.