Subnormothermic Oxygenated Perfusion Optimally Preserves Donor Kidneys Ex Vivo

Abstract

Introduction The current methods of preserving donor kidneys in nonoxygenated cold conditions minimally protect the kidney against ischemia-reperfusion injury (IRI), a major source of complications in clinical transplantation. However, preserving kidneys with oxygenated perfusion is not currently feasible due to the lack of an ideal perfusion mechanism that facilitates perfusion with blood at warm temperature. Here, we have designed an innovative renal pump circuit system that can perfuse blood or acellular oxygen carrier under flexible temperatures, pressures, and oxygenation. We have tested this apparatus to study optimal conditions of storage of our porcine model of donation after cardiac death (DCD) kidneys. Methods Porcine kidneys were retrieved after 30 minutes of cross-clamping renal pedicles in situ . Cessation of blood mimics postcardiac death in humans and simulates DCD warm ischemic injury. Procured kidneys were flushed and subjected to static cold storage (SCS) for 4 hours. For warm perfusion, kidneys were cannulated for pulsatile oxygenated perfusion with blood:PlasmaLyte for 4 hours at 15 °C, 22 °C, and 37 °C. To mimic posttransplant scenario, all kidneys were reperfused with blood for an additional 4 hours at 37 °C. Results Compared with all other groups, 22 °C perfusion resulted in significant reduction of acute tubular necrosis (ATN), apoptosis, kidney damage markers, Toll-like receptor signaling, and cytokine production. It was associated with maximal renal blood flow and urine output. Kidneys stored at 15 °C thrombosed within 2 hours under this condition. Martius Scarlet Blue staining confirmed that 22 °C was the optimal temperature to minimize hemorrhage and blood clots. Conclusion Our novel study shows that oxygenated perfusion at near-room-temperature provides optimal donor kidney storage conditions.

Subnormothermic Perfusion with H2S Donor AP39 Improves DCD Porcine Renal Graft Outcomes in an Ex Vivo Model of Kidney Preservation and Reperfusion

“…Subsequently, both kidneys were nephrectomized, and the donor animal was euthanized. Autologous blood used for perfusion was collected via cannulation of the inferior vena cava before and after clamping the renal pedicles [ 23 ]. Blood collected prior to clamping is referred to as non-stressed blood, because there is no interruption of the blood flow.…”

“…The dose of AP39 was chosen based on a previous in vivo murine transplantation study by our group [ 10 ]. The kidneys were perfused using an ex vivo pulsatile perfusion apparatus ( Figure 1 B), which was identical to the setup used in a previous study by our center [ 23 ]. Through adjusting the flow, the mean perfusion pressure was maintained at 60 mmHg after an initial 5-min period of gradual increase.…”

“…Our group has previously shown that adding AP39 to the University of Wisconsin (UW) solution, a preservation solution that is routinely used for SCS, made it viable for subnormothermic preservation at 21 °C [ 22 ]. We also showed that subnormothermic perfusion at 21 °C improved DCD porcine renal graft outcomes compared to SCS, subnormothermic perfusion at 15 °C and normothermic perfusion at 37 °C [ 23 ]. In this study, we investigate whether subnormothermic perfusion at 21 °C with H 2 S donor AP39 improves DCD porcine renal graft outcomes compared to SCS and subnormothermic perfusion without AP39, using ex vivo pulsatile perfusion for preservation and reperfusion.…”

The Effect of Preservation Temperature on Liver, Kidney, and Pancreas Tissue ATP in Animal and Preclinical Human Models

“…A recent porcine transplant study by Bhattacharjee et al [50] reported that a perfusion temperature of 22 • C resulted in significant improvements on IRI injuries in SCS treated kidneys in terms of histology, suppression of expression of IRI related Toll-like receptor signalling molecules (MyD88, NF-kB and HMGB1), and graft functions, such as increase in urinary output and maximal renal blood flow compared to MP at 15 • C and 37 • C. While it was accepted that a hypothermic temperature may be optimal for the protection of metabolic energetic status and viability of kidney grafts, effects of subnormothermia on tissue ATP remains to be established in comparison to other more extensively studied temperatures.…”

Kidney Perfusion as an Organ Quality Assessment Tool—Are We Counting Our Chickens Before They Have Hatched?

“…Indeed, both acellular and cellular perfusates have been used, showing that subnormothermic perfusion without an oxygen carrier is feasible [57,58]. Until now, subnormothermic kidney preservation has only been tested in DCD models of ex situ perfusion of pig kidneys [57][58][59][60]. Hoyer et al found improved kidney function after subnormothermic compared to oxygenated hypothermic kidney perfusion [60].…”