Peroxiredoxin-2 as a candidate biomarker to test oxidative stress levels of stored red blood cells under blood bank conditions

BACKGROUND: Several researches on aging red blood cells (RBCs)-performed both in vivo and under blood bank conditions-revealed that RBC membrane proteins undergo a number of irreversible alterations, mainly due to oxidative stress. The individuation of proteins to be used as indicators of irreversible RBC injury and to be proposed as candidate biomarkers of oxidative damage or aging status during blood storage is therefore of great interest. STUDY DESIGN AND METHODS: Based on this purpose we performed proteomic analysis of the membranes of RBCs during various storage periods under blood bank conditions. Changes in protein composition of RBC membranes were monitored as a function of the storage period by means of polyacrylamide gel electrophoresis coupled with immunoblotting and mass spectrometry analyses. RESULTS: During storage, a progressive linkage of typical cytosolic proteins to the membrane was detected, including both antioxidant and metabolic enzymes (such as catalase, peroxiredoxin-2 [Prx2], and 2,3-bisphosphoglycerate-mutase), as well as nonreducible cross-linkings of probably oxidized or denatured hemoglobin. This phenomenon was unequivocally related to oxidative stress, since storage of RBCs under anaerobic conditions showed a suppression of these protein recruitments to the membrane. CONCLUSION: The detailed analysis of these protein associations to the membrane of aged RBCs allowed Prx2 to be suggested as a potential RBC oxidative stress marker for the sake of developing new approaches in quality assurance of blood components.