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

The recent advances in machine perfusion (MP) technology involve settings ranging between hypothermic, subnormothermic, and normothermic temperatures. Tissue level adenosine triphosphate (ATP) is a long-established marker of viability and functionality and is universal for all organs. In the midst of a growing number of complex clinical parameters for the quality assessment of graft prior to transplantation, a revisit of ATP may shed light on the underlying reconditioning mechanisms of different perfusion temperatures in the form of restoration of metabolic and energy status. This article aims to review and critically analyse animal and preclinical human studies (discarded grafts) during MP of three abdominal organs (liver, kidney, and pancreas) in which ATP was a primary endpoint. A selective review of recent novel reconditioning approaches relevant to mitigation of graft ischaemia-reperfusion injury via MP and for different perfusion temperatures was also conducted. With a current reiterated interest for oxygenation during MP, a re-introduction of tissue ATP levels may be valuable for graft viability assessment prior to transplantation. Further studies may help delineate the benefits of selective perfusion temperatures on organs viability.

Machine Perfusion for Abdominal Organ Preservation: A Systematic Review of Kidney and Liver Human Grafts.

INTRODUCTION: To match the current organ demand with organ availability from the donor pool, there has been a shift towards acceptance of extended criteria donors (ECD), often associated with longer ischemic times. Novel dynamic preservation techniques as hypothermic or normothermic machine perfusion (MP) are increasingly adopted, particularly for organs from ECDs. In this study, we compared the viability and incidence of reperfusion injury in kidneys and livers preserved with MP versus Static Cold Storage (SCS). METHODS: Systematic review and meta-analysis with a search performed between February and March 2019. MEDLINE, EMBASE and Transplant Library were searched via OvidSP. The Cochrane Library and The Cochrane Central Register of Controlled Trials (CENTRAL) were also searched. English language filter was applied. RESULTS: the systematic search generated 10,585 studies, finally leading to a total of 30 papers for meta-analysis of kidneys and livers. Hypothermic MP (HMP) statistically significantly lowered the incidence of primary nonfunction (PMN, p = 0.003) and delayed graft function (DGF, p < 0.00001) in kidneys compared to SCS, but not its duration. No difference was also noted for serum creatinine or eGFR post-transplantation, but overall kidneys preserved with HMP had a significantly longer one-year graft survival (OR: 1.61 95% CI: 1.02 to 2.53, p = 0.04). Differently from kidneys where the graft survival was affected, there was no significant difference in primary non function (PNF) for livers stored using SCS for those preserved by HMP and NMP. Machine perfusion demonstrated superior outcomes in early allograft dysfunction and post transplantation AST levels compared to SCS, but however, only HMP was able to significantly decrease serum bilirubin and biliary stricture incidence compared to SCS. CONCLUSIONS: MP improves DGF and one-year graft survival in kidney transplantation; it appears to mitigate early allograft dysfunction in livers, but more studies are needed to prove its potential superiority in relation to PNF in livers.