Perfusion of isolated rat kidney with Mesenchymal Stromal Cells/Extracellular Vesicles prevents ischaemic injury

Background. Kidney donation after circulatory death (DCD) is a challenging way to face organ shortage. Hypothermic machine perfusion (HMP) with Belzer solution (BS) improves viability of DCD kidneys, though graft clinical course remains critical. Mesenchymal stromal cells (MSC) promote tissue repair releasing microvesicles (MV). Objective. We evaluated whether delivering MSC/MSC derived MV during HMP protects rat DCD kidneys from ischemia injury and investigated the pathogenic mechanisms underlying. Methods. After warm ischemia isolated kidneys were cold-perfused (4 hours) with BS, BS supplemented with MSC or MV. Renal damage was evaluated by histology, renal gene expression by microarray analysis, RT-PCR. Malondialdehyde, lactate, LDH, glucose, pyruvate were measured in effluent fluid. Results. MSC/MV treated kidneys showed significantly less global ischemic damage. In MSC/MV groups there was up-regulation of three genes encoding enzymes that improve cell energy metabolism and three genes encoding proteins involved in ion membrane transport. In effluent fluid lactate, LDH, malondialdehyde, glucose were significantly lower and pyruvate higher in MSC/MV kidneys as compared with BS, suggesting a larger use of energy substrates by MSC/MV kidneys. Conclusions. The addition of MSC/MV to BS during HMP protects the kidney from ischemia injury by preserving the enzymatic machinery essential for cell viability and prepares kidney to reperfusion damage.