067 Small carbohydrate-based molecules as potent ice recrystallization inhibitors and their application in red blood cell cryopreservation

Abstract

Red blood cell (RBC) preservation from peripheral blood donations in blood banks has ensured the availability of safe blood supplies for transfusions. RBCs are typically stored refrigerated for a maximum of 42 days. However, more prolonged storage times are required for rare blood type donations and currently the only method available for their long-term storage is cryopreservation. Unfortunately, RBC cryopreservation is costly and time-consuming, requiring extensive washing procedures to reduce the high glycerol cryoprotectant concentration from 40–50% to less than 1%. Consequently, improvements in the RBC cryopreservation process are urgently required. A significant contributor to cellular injury and death during cryopreservation is ice recrystallization. Thus, great interest has arisen in designing ice recrystallization inhibitors for use as novel cryoprotectants. Unfortunately, the structural features necessary for ice recrystallization inhibition (IRI) activity are not known. Potent IRI activity was previously limited to large protein and glycoprotein molecules related to biological antifreezes. However, our laboratory recently reported the first potent small molecule ice recrystallization inhibitors that were carbohydrate-based surfactants and hydrogelators. Further investigation into various other small carbohydrate-based molecules has led to the discovery that several substituted oxygen-linked phenolic-glycosides exhibit potent IRI activity. Structure-function studies have identified that key structural features on these phenolic-glycosides are crucial for potent activity. In particular, the activity of these glycosides is highly sensitive to the position of the functional group on the aromatic ring, as well as hydroxyl group stereochemistry and the nature of the anomeric-linkage on the carbohydrate moiety. The cryoprotective ability of various highly IRI active glycosides with RBCs was also assessed to investigate if glycerol concentrations could be significantly reduced during cryopreservation. These results have indicated that their addition to cryoprotective solutions containing lower glycerol concentrations can decrease post-thaw RBC hemolysis. This is significant as a reduction in glycerol concentration can ultimately decrease deglycerolization times and improve post-thaw RBC quality for transfusions. This presentation will discuss the cryopreservation results and the effectiveness of these highly IRI active glycosides as cryo-additives for RBCs, as well as the structure-function results identifying key structural features important for the IRI activity of phenolic-glycosides. Source of funding: This research was supported by Canadian Blood Services (CBS), Canadian Institutes of Health Research (CIHR) and Natural Sciences and Engineering Research Council of Canada (NSERC). Conflict of interest: None declared. rben@uottawa.ca