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

Abstract

BackgroundThe 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.MethodsNMP 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.ResultsComplement 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.ConclusionNormothermic 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.

Proteomics reveals specific biological changes induced by the normothermic machine perfusion of donor kidneys with a significant up-regulation of Latexin

“…The proteins depleted by NMP treatment included components of the complement system and coagulation cascade, which are involved in the damage to renal tubular cells following I/R injury and in the subsequent inflammatory response [34][35][36] . NMP was previously shown to partially influence this pathway although with contrasting results 37,38 . Our data suggest that the complement pathway may become hyper-activated (in part compensated by the downregulation of C1s proteases) in response to non-immune insults such as I/R.…”

Addition of a liver to the normothermic perfusion circuit reduces renal pro‐inflammatory factors

“…During NMP, higher concentrations of cytokines were detected in the perfusate 23 . Another study by Jager NM et al found a correlation between complement activation during the renal NMP and pro‐inflammatory cytokines such as IL‐6 and IL‐8 24 . Transcriptome data from Ferdinand JR and Hosgood SA also indicated high expression of oxidative phosphorylation and pro‐inflammatory genes in the kidney during NMP, suggesting both beneficial effects and inflammation‐induced damage 3 .…”

“…23 Another study by Jager NM et al found a correlation between complement activation during the renal NMP and pro-inflammatory cytokines such as IL-6 and IL-8. 24 Transcriptome data from Ferdinand JR and Hosgood SA also indicated high expression of oxidative phosphorylation and pro-inflammatory genes in the kidney during NMP, suggesting both beneficial effects and inflammationinduced damage. 3 When they added a hemoadsorption into the renal NMP system, the expression of inflammasome genes such as IL-1β and NLRP3 in the kidney was reduced.…”