Conditioning of porcine kidneys during dynamic preservation with exosomes derived from Urine Progenitor Cells
Backgroud: among strategies to limit ischemia/reperfusion (IR) injuries in transplantation, cell therapy using stem cells to condition/repair transplanted organ appears promising. We hypothesized that using a cell therapy based on exosomes derived from Urine Progenitor Cells (UPCs) during hypothermic and normothermic machine perfusion can prevent IR-related kidney damages.  Methods: we isolated and characterized porcine UPCs and their exosomes (Exo). Then these were used in an ex vivo preclinical porcine kidney preservation model. Kidneys were subjected to warm ischemia (32min) then preserved by Hypothermic Machine Perfusion (HMP) for 24h before 5h of Normothermic Machine Perfusion (NMP). Three groups were performed (n=5-6): Group 1 (G1): HMP/vehicle + NMP/vehicle, Group 2 (G2): HMP/Exo + NMP/vehicle, Group 3 (G3): HMP/Exo + NMP/Exo.  Results: porcine UPCs were successfully isolated from urine and fully characterized as well as their exosomes which were found of expected size/phenotype. RNA-seq performed on kidney biopsies showed different profiles between G1 and G3 with regulation of potential IR targets of Exo therapy. Conclusions: we showed the feasibility/efficacy of UPC-exosomes for hypothermic/normothermic kidney conditioning prior to transplantation, paving the way of combining machine perfusion with exosome-based cell therapy for organ conditioning. Overall design: Porcine kidneys (5-6/group), from Dutch Landrace pigs (6 months to 1 year old)  were collected after 32 min of warm ischemia and submitted to 24h of Hypothermic Machine Perfusion (HMP) followed by 5h Normothermic Machine Perfusion (NMP). Porcine kidneys of Group 1 were injected with PBS-1X during both HMP and NMP; Porcine kidneys of Group 2 were injected with Exosomes during HMP only; Porcine kidneys of Group 3 were injected with Exosomes during both HMP and NMP. At the end of NMP, kidneys were immediately sampled and snap frozen in liquid nitrogen.