Optimizing porcine donor kidney preservation with normothermic or hypothermic machine perfusion: A systematic review.

We present an updated overview of the literature comparing normothermic with hypothermic machine perfusion in porcine kidneys. We conducted a systematic literature review in Embase, Medline Epub (Ovid), Cochrane Central, Web of Science, and Google Scholar on studies comparing normothermic (NMP) to hypothermic machine perfusion (HMP) in porcine kidneys. A meta-analysis was judged inappropriate because of heterogeneity in study design and perfusion methods. The quality of evidence of each included study was assessed. We included 8 studies. One out of 5 studies reported a significant difference in peak renal blood flow in favor of NMP. Oxygen consumption was significantly higher in NMP kidneys in 2 out of 5 studies. Peak creatinine clearance in NMP was significantly higher than that in HMP in 1 out of 6 studies. Two out of 4 studies reported a higher degree of epithelial vacuolation in kidneys receiving NMP over HMP. None of the studies found a significant difference between NMP and HMP in peak serum creatinine or graft survival after autotransplantation. The results need to be interpreted with caution in view of the diversity in perfusion protocols, the low quality of evidence, and the limited sample sizes.

Bouari S ，Eryigit Ö ，de Bruin RWF ，IJzermans JNM ，Minnee RC ... -  《-》

Comparison of normothermic and hypothermic perfusion in porcine kidneys donated after cardiac death.

Normothermic machine perfusion (NMP) is an alternative strategy for preserving kidneys donated after cardiac death (DCD). The relative efficacy of prolonged NMP compared to hypothermic machine perfusion (HMP) in DCD kidneys with moderate ischemic injury is undetermined. This study compares NMP and HMP kidney preservation in a porcine DCD model. Ten porcine kidneys underwent NMP or HMP preservation following 45 minutes of warm ischemia and 5 hours of cold ischemia. After 8 hours of machine preservation, hemodynamic stability, renal function, perfusate biomarkers, and histologic integrity were assessed in a simulated reperfusion model. During simulated reperfusion, no differences were observed in oxygen consumption, urine production, creatinine clearance, fractional excretion of sodium, proteinuria, and perfusate levels of lactate dehydrogenase and aspartate aminotransferase. Resistance was no different after 30 minutes of simulated reperfusion. Histologically, NMP kidneys demonstrated increased vacuolization after preservation and greater loss of tubular integrity after simulated reperfusion. Perfusate levels of alkaline phosphatase (AP) and gamma glutamyltransferase (GGT) were higher in NMP kidneys during preservation, but upon simulated reperfusion, AP and GGT levels were higher in HMP-preserved kidneys. Peak AP and GGT during simulated reperfusion of HMP kidneys were over 14 times higher than peak AP and GGT during preservation of NMP kidneys. NMP provided comparable preservation of renal function as HMP and minimized AP and GGT release upon reperfusion.

Blum MF ，Liu Q ，Soliman B ，Dreher P ，Okamoto T ，Poggio ED ，Goldfarb DA ，Baldwin WM 3rd ，Quintini C ... -  《-》

A Comparison of Pulsatile Hypothermic and Normothermic Ex Vivo Machine Perfusion in a Porcine Kidney Model.

Hypothermic machine perfusion (HMP) is a well-established method for deceased donor kidney preservation. Normothermic machine perfusion (NMP) might offer similar or greater advantages. We compared the 2 methods in an ex vivo perfusion model using 34 porcine kidneys. Thirty kidneys were stored on ice for 24 h before undergoing 4 h of HMP (n = 15) or NMP (n = 15) followed by 2 h of normothermic ex vivo reperfusion with whole blood. Four kidneys underwent 28 h of cold static storage followed by 2 h of normothermic ex vivo reperfusion. During the 2 h of normothermic ex vivo reperfusion, perfusate flow rates, urinary output, and oxygen consumption rates were compared between all groups. Porcine kidneys after HMP showed significantly higher urinary output (5.31 ± 2.06 versus 2.44 ± 1.19 mL/min; P = 0.002), oxygen consumption (22.71 ± 6.27 versus 11.83 ± 1.29 mL/min; P = 0.0016), and perfusate flow rates (46.24 ± 12.49 versus 26.16 ± 4.57 mL/min; P = 0.0051) than kidneys after NMP. TUNEL staining of tissue sections showed significantly higher rates of apoptosis in kidneys after NMP (P = 0.027). In our study, the direct comparison of HMP and NMP kidney perfusion in a translational model demonstrated superiority of HMP; however, further in vivo studies would be needed to validate those results.

Vallant N ，Wolfhagen N ，Sandhu B ，Hamaoui K ，Cook T ，Pusey C ，Papalois V ... -  《-》

Complement Is Activated During Normothermic Machine Perfusion of Porcine and Human Discarded Kidneys.

The gap between demand and supply of kidneys for transplantation necessitates the use of kidneys from extended criteria donors. Transplantation of these donor kidneys is associated with inferior results, reflected by an increased risk of delayed graft function. Inferior results might be explained by the higher immunogenicity of extended criteria donor kidneys. Normothermic machine perfusion (NMP) could be used as a platform to assess the quality and function of donor kidneys. In addition, it could be useful to evaluate and possibly alter the immunological response of donor kidneys. In this study, we first evaluated whether complement was activated during NMP of porcine and human discarded kidneys. Second, we examined the relationship between complement activation and pro-inflammatory cytokines during NMP. Third, we assessed the effect of complement activation on renal function and injury during NMP of porcine kidneys. Lastly, we examined local complement C3d deposition in human renal biopsies after NMP. NMP with a blood-based perfusion was performed with both porcine and discarded human kidneys for 4 and 6 h, respectively. Perfusate samples were taken every hour to assess complement activation, pro-inflammatory cytokines and renal function. Biopsies were taken to assess histological injury and complement deposition. Complement activation products C3a, C3d, and soluble C5b-9 (sC5b-9) were found in perfusate samples taken during NMP of both porcine and human kidneys. In addition, complement perfusate levels positively correlated with the cytokine perfusate levels of IL-6, IL-8, and TNF during NMP of porcine kidneys. Porcine kidneys with high sC5b-9 perfusate levels had significantly lower creatinine clearance after 4 h of NMP. In line with these findings, high complement perfusate levels were seen during NMP of human discarded kidneys. In addition, kidneys retrieved from brain-dead donors had significantly higher complement perfusate levels during NMP than kidneys retrieved from donors after circulatory death. Normothermic kidney machine perfusion induces complement activation in porcine and human kidneys, which is associated with the release of pro-inflammatory cytokines and in porcine kidneys with lower creatinine clearance. Complement inhibition during NMP might be a promising strategy to reduce renal graft injury and improve graft function prior to transplantation.

Jager NM ，Venema LH ，Arykbaeva AS ，Meter-Arkema AH ，Ottens PJ ，van Kooten C ，Mollnes TE ，Alwayn IPJ ，Leuvenink HGD ，Pischke SE ，PROPER study consortium ... -  《Frontiers in Immunology》

Oxygen Consumption by Warm Ischemia-Injured Porcine Kidneys in Hypothermic Static and Machine Preservation.

Static cold storage (SCS) and hypothermic machine perfusion (HMP) are currently standard methods for renal grafts clinical preservation. Both methods are predominantly implemented without the active delivery of oxygen, even for donation after circulatory death-like kidneys. However, even under severe hypothermia (4°C-6°C), kidneys can consume oxygen and produce ATP. What is not established, though, is to what extent and how SCS and HMP compare in terms of oxygen. Using a porcine preclinical model of renal warm ischemia (WI) to compare SCS and HMP methods, we continuously monitored and quantified oxygen level and consumption along preservation; we also determined prepreservation and postpreservation cortical ATP level; values were given as median and [min; max] range. One-hour WI reduced ATP by ∼90% (from 3.3 [1.7; 4.5] mmol/L tissue in Controls). Oxygen consumption (QO2, μmol/min per 100 g) was determined from initial solution PO2 decrease (SCS and HMP) and from arterio-venous difference (HMP). In SCS and HMP, PO2 decreased rapidly (t1/2 ∼1 h) from atmospheric levels to 52.9 [38.0; 65.9] and 8.2 [3.0, 16.0] mmHg, respectively. In HMP, QO2 was 2.7 [0.4; 3.9] versus 0.5 [0.0; 1.3] in SCS (P < 0.05); postpreservation ATP amounted to 5.8 [3.2; 6.5] in HMP versus 0.1 [0.0; 0.2] in SCS. Despite hypothermic conditions in SCS or HMP, donation after circulatory death-like renal grafts require oxygen. Increased oxygen consumption, restored ATP level, and improved histological profile in HMP might explain the established HMP superiority over SCS. These results establish a rational basis for the use of oxygen in hypothermic preservation. Optimal levels required for preservation and graft-type variants remain to be determined.

Kaminski J ，Delpech PO ，Kaaki-Hosni S ，Promeyrat X ，Hauet T ，Hannaert P ... -  《-》