Subnormothermic perfusion with h2s donor ap39 improves dcd porcine renal graft outcomes in an ex vivo model of kidney preservation and reperfusion

This is the final published version, also available from MDPI via the DOI in this record.Cold preservation is the standard of care for renal grafts. However, research on alterna-tives like perfusion at higher temperatures and supplementing preservation solutions with hydrogen sulfide (H2S) has gained momentum. In this study, we investigated whether adding H2S donor AP39 to porcine blood during subnormothermic perfusion at 21 °C improves renal graft outcomes. Porcine kidneys were nephrectomized after 30 min of clamping the renal pedicles and treated to 4 h of static cold storage (SCS) on ice or ex vivo subnormothermic perfusion at 21 °C with autologous blood alone (SNT) or with AP39 (SNTAP). All kidneys were reperfused ex vivo with autologous blood at 37 °C for 4 h. Urine output, histopathology and RNAseq were used to evaluate the renal graft function, injury and gene expression profiles, respectively. The SNTAP group exhibited significantly higher urine output than other groups during preservation and reperfusion, along with significantly lower apoptotic injury compared to the SCS group. The SNTAP group also exhibited differential pro-survival gene expression patterns compared to the SCS (downregulation of pro-apoptotic genes) and SNT (downregulation of hypoxia response genes) groups. Subnormothermic perfusion at 21 °C with H2S-supplemented blood improves renal graft outcomes. Further research is needed to facilitate the clinical translation of this approach.Medical Research Council (MRC)Physicians Services Incorporated (PSI) FoundationLawson Research Institut

Evaluating the effects of subnormothermic perfusion with ap39 in a novel blood‐free model of ex vivo kidney preservation and reperfusion

This is the final version. Available on open access from MDPI via the DOI in this recordData Availability Statement: The data presented in this study are available on request from the corresponding author.The use of blood for normothermic and subnormothermic kidney preservation hinders the translation of these approaches and promising therapeutics. This study evaluates whether adding hydrogen sulfide donor AP39 to Hemopure, a blood substitute, during subnormothermic perfusion improves kidney outcomes. After 30 min of renal pedicle clamping, porcine kidneys were treated to 4 h of static cold storage (SCS‐4 °C) or subnormothermic perfusion at 21 °C with Hemopure (H‐21 °C), Hemopure + 200 nM AP39 (H200nM‐21 °C) or Hemopure + 1 μM AP39 (H1μM‐21 °C). Then, kidneys were reperfused with Hemopure at 37 °C for 4 h with metabolic support. Perfusate composition, tissue oxygenation, urinalysis and histopathology were analyzed. During preservation, the H200nM‐21 °C group exhibited significantly higher urine output than the other groups and significantly higher tissue oxygenation than the H1μM‐21 °C group at 1 h and 2h. During reperfusion, the H200nM‐21 °C group exhibited significantly higher urine output and lower urine protein than the other groups. Additionally, the H200nM‐21 °C group exhibited higher perfusate pO2 levels than the other groups and significantly lower apoptotic injury than the H‐21 °C and the H1μM‐21 °C groups. Thus, subnormothermic perfusion at 21 °C with Hemopure + 200 nM AP39 improves renal outcomes. Additionally, our novel blood‐free model of ex vivo kidney preservation and reperfusion could be useful for studying other therapeutics.Physicians Services Incorporated (PSI) FoundationKidney Foundation of Canad

Hydrogen sulphide-induced hypometabolism in human-sized porcine kidneys

Background Since the start of organ transplantation, hypothermia-forced hypometabolism has been the cornerstone in organ preservation. Cold preservation showed to protect against ischemia, although post-transplant injury still occurs and further improvement in preservation techniques is needed. We hypothesize that hydrogen sulphide can be used as such a new preservation method, by inducing a reversible hypometabolic state in human sized kidneys during normothermic machine perfusion. Methods Porcine kidneys were connected to an ex-vivo isolated, oxygen supplemented, normothermic blood perfusion set-up. Experimental kidneys (n = 5) received a 85mg NaHS infusion of 100 ppm and were compared to controls (n = 5). As a reflection of the cellular metabolism, oxygen consumption, mitochondrial activity and tissue ATP levels were measured. Kidney function was assessed by creatinine clearance and fractional excretion of sodium. To rule out potential structural and functional deterioration, kidneys were studied for biochemical markers and histology. Results Hydrogen sulphide strongly decreased oxygen consumption by 61%, which was associated with a marked decrease in mitochondrial activity/function, without directly affecting ATP levels. Renal biological markers, renal function and histology did not change after hydrogen sulphide treatment. Conclusion In conclusion, we showed that hydrogen sulphide can induce a controllable hypometabolic state in a human sized organ, without damaging the organ itself and could thereby be a promising therapeutic alternative for cold preservation under normothermic conditions in renal transplantation