Abstract
The shortage of donor organs has led to an increased use of extended-criteria donors and donation after circulatory death for kidney transplantation, both of which are associated with graft injury. Although machine perfusion (MP) offers a preservation strategy, the most beneficial approach for kidneys with respect to effective graft preservation remains unclear. We compared oxygenated hypothermic (HMP) and normothermic machine perfusion (NMP) using a murine kidney perfusion model regarding intra-graft immune cell composition, viability, and inflammatory responses. NMP resulted in more severe tubular injury, accompanied by increased immune cell mobilization out of the graft. NMP increased early apoptosis among kidney-resident immune-cell populations, whereas endothelial cells showed increased late apoptosis after both strategies. Proximal tubular-cell apoptosis remained comparable to naive tissue, and neither modality reduced reactive oxygen species levels. Both protocols induced antioxidant and hypoxia-responsive genes compared with static cold storage, while NMP elicited a stronger inflammatory response. Treatment with the senolytic ABT-263 demonstrated the models feasibility for investigating renal injury, cellular viability, and immune activation during MP.