Hallym University College of Medicine Anyang-si, United States
Background/Case Studies: The global shortage of human blood has driven interest in xenotransfusion using porcine red blood cells (pRBCs), due to their physiological similarities to human RBCs (hRBCs). While preservation methods for hRBCs are well-established for both short- and long-term storage, protocols for pRBCs remain underdeveloped, limiting clinical application. This study assesses the stability of pRBCs under various storage conditions to inform future xenotransfusion strategies.
Study
Design/Methods: Whole blood was collected from genetically engineered pigs (n=14; TKO, TKO/hCD55.hCD39KI, QKO) and processed into packed RBCs. Discarded clinical samples from healthy human donors (n=29) were used to prepare hRBCs. Both groups were stored at 4°C for 28 days. Hematological and biochemical parameters were evaluated at defined time points. Cryopreservation followed a glycerolization–deglycerolization protocol. Post-thaw quality was assessed by RBC count, hemoglobin (Hb), free Hb, and lactate dehydrogenase (LDH) levels.
Results/Findings: Baseline differences were observed between hRBCs and pRBCs in parameters such as RBC count, free Hb, and LDH, necessitating normalization via relative change (delta value) analysis. By days 7 and 28, pRBCs exhibited significantly higher increases in delta free Hb compared to hRBCs (P = 0.00105, 0.0386), indicating progressive hemolysis. From day 21 onward, significant differences emerged in delta albumin and calcium (P < 0.05), suggestive of membrane instability and ion imbalance. Delta RBC count in pRBCs declined significantly by day 28 (P = 0.0115), whereas hRBCs remained relatively stable. Cryopreservation pilot results showed acceptable recovery in hRBCs. In contrast, pRBCs exhibited reduced post-thaw RBC count and hemoglobin levels, along with a substantial increase in free hemoglobin and LDH, indicating extensive hemolysis.
Conclusions: Short-term refrigerated storage maintains acceptable pRBC quality for up to 7 days, supporting their potential in acute xenotransfusion. However, progressive hemolysis and late-onset membrane instability were evident after day 21. Compared to hRBCs, pRBCs showed reduced resilience during both refrigeration and cryopreservation. These findings underscore the need for species-specific preservation protocols. Future work should focus on enhancing membrane stability and optimizing cryoprotective strategies to improve the viability of pRBCs for clinical use.
