OxyVita®C Hemoglobin-Based Oxygen Carrier Improves Viability and Reduces Tubular Necrosis in Ex Vivo Preserved Rabbit Kidneys

Organ transplantation has significantly progressed since the 1950s, with notable advancements in surgical procedures and immunosuppression. However, current organ preservation techniques, mainly static cold storage, have not evolved at the same pace and remain insufficient to prevent ischemic and oxidative damage. This damage, primarily caused by the cessation of aerobic metabolism, limits organ viability and transplant outcomes. In this study, we investigated whether supplementing a storage solution with a hemoglobin-based oxygen carrier (HBOC) could improve the condition of ex vivo rabbit kidneys by maintaining oxygenation and supporting aerobic metabolism. In a paired, randomized design, contralateral rabbit kidneys were preserved either in a Krebs-Ringer-based solution enriched with the polymerized hemoglobin OxyVita^®C (15 g/L, p50 4-6 mmHg, MW ≈ 17 MDa, pH adjusted to 7.4) or in an HBOC-free control solution. Physicochemical characterization of OxyVita^®C included oxygen equilibrium curves, zeta potential, polydispersity index, and dynamic light scattering. Biochemical markers (AST, ALT, LDH, K⁺, pH) and histopathological assessments were used to evaluate tissue integrity over 24 h. Histology was additionally stratified according to rinsing protocols (unwashed, NaCl single flush, triple flush), and tubular necrosis was scored by blinded pathologists. Group comparisons were analyzed using ANOVA with Tukey's HSD test. The HBOC-enriched solution showed improved tissue preservation, higher cell survivability, and better histomorphological profiles, with significantly reduced tubular necrosis scores compared to controls. These findings suggest that active oxygen delivery via HBOCs offers a promising strategy to mitigate ischemic damage during ex vivo kidney storage. Limitations include the lack of transplantation outcomes and direct ROS quantification, which will be addressed in future work integrating hypothermic and normothermic machine perfusion.