Effects of oxygen on red cells during liquid storage at +4 degrees C.

Red cells collected in CPD and suspended in SAGM medium were stored in plastic (PVC) containers for 42 days at +4 degrees C. Comparison was made between aerobic storage (normal air exposure) and anaerobic storage (exposure to nitrogen gas). The air-exposed units showed a strong increase in pO2 and oxygen saturation as a result of oxygen penetration into the bags from outside. This resulted in a decrease in ATP and adenylate energy charge, a slower metabolization of adenine and hypoxanthine to AMP and IMP, respectively, and a faster decrease in red cell fluidity. To explain the findings it is concluded that aerobic storage causes an increased need of high-energy phosphate groups, possibly used for replacement of the phospholipid membrane bilayer or in repair of phosphate bonds in the cytoskeleton. It is further proposed that a slight formation of hydrogen peroxide from free oxygen radicals moderately increases the oxidation of reduced (GSH) to oxidized (GSSG) glutathione and slightly enhances the need for reduced nicotinamide-adenine dinucleotides mainly provided by increased flux through the pentose phosphate shunt.