contributed equally to this work.Abbreviations: ADP, adenosine diphosphate; AMP, adenosine monophosphate; ATP, adenosine triphosphate; CIT, cold ischemia time; DBD, donation after brain death; DCD, donation after circulatory death; FENa, fractional excretion of sodium; HBOC, hemoglobin-based oxygen carrier; HMP, hypothermic machine perfusion; NEDS, New England Donor Services; NEVKP, normothermic ex vivo kidney perfusion; NMP, normothermic machine perfusion; PRBC, packed red blood cells; QAS, quality assessment score; SCS, static cold storage; WIT, warm ischemia time.Normothermic machine perfusion presents a novel platform for pretransplant assessment and reconditioning of kidney grafts. Maintaining the metabolic activity of a preserved graft at physiologic levels requires an adequate oxygen supply, typically delivered by crystalloid solutions supplemented with red blood cells. In this study, we explored the feasibility of using a synthetic hemoglobin-based oxygen carrier (HBOC) in human kidney normothermic perfusion. Fourteen discarded human kidneys were perfused for 6 hours at a mean temperature of 37°C using a pressurecontrolled system. Kidneys were perfused with a perfusion solution supplemented with either HBOC (n = 7) or packed red blood cells (PRBC) (n = 7) to increase oxygencarrying capacity. Renal artery resistance, oxygen extraction, metabolic activity, energy stores, and histological features were evaluated. Throughout perfusion, kidneys from both groups exhibited comparable behavior regarding vascular flow (P = .66), oxygen consumption (P = .88), and reconstitution of tissue adenosine triphosphate (P = .057). Lactic acid levels were significantly higher in kidneys perfused with PRBC (P = .007). Histological findings were comparable between groups, and there was no evidence of histological damage caused by the HBOC. This feasibility experiment demonstrates that a HBOC solution can offer a logistically more convenient off-theshelf alternative to PRBC in normothermic machine perfusion of human kidneys.
K E Y W O R D Sbasic (laboratory) research/science, kidney transplantation/nephrology, organ perfusion and preservation, organ procurement and allocation, tissue/organ engineering, translational research/science | 2815 ABURAWI et Al.