MP52-01 EVALUATING THE EFFECT OF SUBNORMOTHERMIC PRESERVATION WITH HYDROGEN SULFIDE DONOR AP39 ON PORCINE DCD RENAL GRAFT OUTCOMES USING A NOVEL EX VIVO BLOOD-FREE MODEL OF KIDNEY PERFUSION

Abstract

INTRODUCTION AND OBJECTIVE: While cold storage of organs prior to renal transplantation is the clinical standard of care, it has been shown to exacerbate renal ischemia-reperfusion injury. Adding hydrogen sulfide (H2S) to University of Wisconsin solution during cold storage has been shown to ameliorate post-transplant graft function and injury. Recent studies have also established alternatives, such as subnormothermic and normothermic machine perfusion, that improve graft outcomes compared to cold storage. However, the need for donor blood complicates the clinical translation of normothermic and subnormothermic perfusion. As such, hemoglobin-based oxygen carriers, such as Hemopure, are of interest. This study evaluates the effects of blood-free renal graft preservation and reperfusion with Hemopure. Additionally, we assess the effect of adding H2S donor AP39 to Hemopure during subnormothermic preservation. METHODS: Following 30m of warm ischemia to mimic donation after cardiac death (DCD), both kidneys were nephrectomized and preserved using static cold storage (SCS) on ice (4°C) or ex vivo subnormothermic perfusion (21°C) with Hemopure or Hemopure + 200nM AP39 (n=6 in each group). Following 4h of preservation, all kidneys were reperfused (37°C) for 4h with Hemopure supplemented with nutrients. Urine output, tissue oxygenation and perfusate parameters (pH, lactate, pO2, pCO2, electrolytes) were measured hourly during reperfusion. Histopathological analyses were conducted after reperfusion through TUNEL and H&E staining. RESULTS: Subnormothermic perfusion with Hemopure + 200nM AP39 resulted in significantly higher urine output (p<0.05) during preservation compared to perfusion with Hemopure alone. During reperfusion, kidneys preserved with Hemopure + 200nM AP39 exhibited significantly higher urine output (p<0.05) than kidneys preserved using SCS or Hemopure alone. Preservation with Hemopure and Hemopure + 200nM AP39 led to higher tissue oxygenation during reperfusion than SCS. All groups were comparable in terms of perfusate parameters and histopathology scores. CONCLUSIONS: We demonstrate, for the first time, that subnormothermic perfusion at 21°C with Hemopure + AP39 improves renal graft outcomes compared to SCS, the standard of care, using a bloodfree model of preservation and reperfusion. This novel blood-free model can be used to test other drug therapies for kidney preservation and evaluate organ function ex vivo prior to transplantation.