Inhibition of Glutathione Synthesis via Decreased Glucose Metabolism in Stored RBCs.

BACKGROUND/AIMS: Although red blood cells (RBCs) transfusions can be lifesaving, they are not without risk. RBCs storage is associated with the abnormal metabolism of glutathione (GSH), which may increase the risk of the oxidative damage of RBCs after transfusion. The responsible mechanisms remain unknown.

METHODS: We determined the L-cysteine efflux and influx by evaluating the changes of free -SH concentrations in stored RBCs. The glutamate cysteine ligase (GCL) activities and protein content in stored RBCs was determined by fluorescence assay and western blotting. In addition, the glucose metabolism enzyme activity of RBCs was measured by spectrophotometric assay under in vitro incubation conditions.

RESULTS: We found that both L-cysteine transport and GCL activity significantly declined, thereby inducing the dysfunction of GSH synthesis during blood storage, which could be attenuated by ATP supplement and DTT treatment. In addition, the glycometabolic enzyme (G6PDH, HK, PK and LDH) activity significantly decreased after 6 weeks storage. Oxidant stress-induced dysfunction in glucose metabolism was the driving force for decreased GSH synthesis during storage.

CONCLUSION: These experimental findings reflect an underlying molecular mechanism that oxidant stress induced glucose metabolism dysfunction contribute to decreased GSH synthesis in stored RBCs.