The ability to preserve metabolically active kidneys ex vivo for multiple days may permit reconditioning, repair and regeneration of deceased donor kidneys. However, the kidneys high metabolic demand limits its functional preservation. Current approaches focus on normothermic machine perfusion (NMP) at 37C or hypothermic machine perfusion (HMP) at 4-8C. At normothermia, kidneys are metabolically active but ex vivo preservation is limited to hours. During hypothermia kidneys can be preserved up to 24 hours but are metabolically inactive and suffer cold-induced injury. Therefore, we revisited sub normothermic perfusion (at 25C) as an alternative approach to preserve human kidneys in a metabolically active state for extended periods of time. In a custom-made platform that includes a cell-free perfusate enriched with TCA cycle fuels, urine recirculation, and continuous hemofiltration we perfused discarded human kidneys up to 8 days. Using spatially resolved single cell resolution isotope tracing we demonstrate active metabolism in all the different renal cell types over this period. However, beyond 4 days cell composition of nephron segments assessed with spatial lipidomics changed substantially and injury markers such as NGAL and LDH increased in the perfusate. Up to 4 days, perfused human discarded donor kidneys maintained metabolic fluxes, functional parameters and allow for reperfusion using a porcine auto transplantation model. These data underpin that extended multi-day metabolic preservation of human kidneys is achievable using a sub normothermic perfusion platform.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.