Sanne de Bruin

163 Storage of RBCs in PAGGGM improves metabolism after transfusion but has no effect on PTR Purine metabolism and free fatty acids metabolism in 35 days stored SAGM RBCs During storage in SAGM, increased purine metabolism was found. Hypoxanthine and xanthine levels were significantly higher in 35 days stored SAGM RBCs compared to 2-days stored SAGM RBCs. In addition, the precursors AMP, adenosine and fumarate were also significantly higher after 35 days of storage. However, directly after transfu- sions, none of the differences between fresh and stored RBCs remained. Arachidonic acid was significantly higher prior to transfusion in the 35-days stored RBCs. After transfusion, no difference in arachidonic acid levels was found in the restored cells. The other investigated fatty acids (palmitoleic acid, palmitic acid, stearic acid, oleic acid and linoleic acid), were not affected by storage time in this study. Discussion This is the first randomized trial investigating the PTR and metabolic recovery of trans- fused RBCs in different additive solutions using biotinylated autologous RBCs. Themain findings of this study are: 1) longer storage time of RBCs is associated with a decreased PTR at 2-7 days after transfusion, 2) despite a better preservation of the glycolysis, PPP and redox metabolism, storage of RBCs in PAGGGM did not result in an increased PTR and 3) despite the metabolic storage lesion, transfused RBCs that can survive the first day after transfusion are characterized by normalization of glycolysis the pentose phosphate pathway, purine metabolism and fatty acid metabolism. A negative effect of storage time on PTR has been reported previously 1 . However, in our study we found a different timing of this effect. We found a significantly lower PTR two-seven days after transfusion, but no significant difference in the first 24 hours. This is in contrast with the study of Luten et al. where, longer stored RBCs had a decreased 24-hour PTR. Moreover, in the study by Luten et al . the cells that survived the first 24 hours had a similar lifespan as the shorter stored RBCs 1 . First of all, it is worth noting that Luten et al. had relied on classic 51 Chromium radiolabeling to determine PTR, while here we employed biotinylation strategies. The discrepancies between the 51 Cr labeling method and biotinylationmay be attributable to the different findings. Other significant differences include the type of recipient, while we examined healthy volunteers, in the study of Luten et al. PTR was assessed in haematological patients. It has been shown that underlying disease such as sepsis is associated withmarkers of increased clearance including decreased deformability 28,29 . Another explanation 6