Protein and lipid oxidation of banked human erythrocytes: Role of glutathione

In banked human erythrocytes (RBCs), biochemical and functional changes are accompanied with vesiculation and reduced in vivo survival. We hypothesize d that some of these changes might have resulted from oxidative modificatio n of membrane lipids, proteins, or both as a result of atrophy of the antio xidant defense system(s). In banked RBCs, we observed a time-dependent incr ease in protein clustering, especially band 3; carbonyl modification of ban d 4.1; and malondialdehyde, a lipid peroxidation product. Examination of th e antioxidative defense system showed a time-dependent decline in glutathio ne (GSH) concentration and glutathione-peroxidase (GSH-PX) activity, with a concomitant increase in extracellular GSH, cysteine, and homocysteine, and unchanged catalase activity. When subjected to acute oxidant stress by exp osure to ferric/ascorbic acid or tert-butylhydroperoxide (tert-BHT), catala se activity showed a steeper decline compared with GSH-PX. The results demo nstrate that GSH and GSH-PX appear to provide the primary antioxidant defen se in stored RBCs, and their decline, concurrent with an increase in oxidat ive modifications of membrane lipids and proteins, may destabilize the memb rane skeleton, thereby compromising RBC survival. (C) 1999 Elsevier Science Inc.