Kidney storage at subzero temperature is safe for porcine kidney autotransplantation: A world first in vivo study

Organ shortage continues to limit kidney transplantation worldwide. Subzero storage may harbor the potential for extending cold ischemic times, improving organ sharing, and optimizing graft allocation. However, subzero storage remains challenging, limited by possible freeze-thaw damage. We used a porcine autotransplant model to assess kidney function and injury after brief (5 hours) or prolonged (24-48 hours) subzero storage of grafts, comparing it to classic static cold storage. There was no mortality in the cohort, and subjects were followed for 7 days. Creatinine, blood urea nitrogen, and potassium peak levels and curves were comparable between groups in both brief and prolonged experiments (P > .05). Histologic analysis revealed no evidence suggesting ice crystals had formed, as well as similar injury profiles, suggesting that the subzero preservation process was successful. Creatinine clearance, fractional excretion of sodium, and neutrophil gelatinase-associated lipocalin urinary and serum levels tended to favor subzero preservation in the 24-hour static cold storage experiments, without statistical significance. Although further research is needed to optimize storage protocols and explore the impact of colder temperatures, this study provides promising evidence regarding the safety and feasibility of subzero storage as a method for extending preservation times. Future studies will focus on enhancing preservation solutions for improved outcomes.