Development of pancreatic machine perfusion: translational steps from porcine to human models

Hypothermic machine perfusion (HMP) is increasingly being used for extended criteria kidney grafts. Pancreatic HMP is challenging because physiologically the pancreas is a low-flow organ susceptible to edema. We report the successful development of preclinical HMP models using porcine pancreases, as well as human pancreases unsuitable for clinical transplantation. Ten porcine pancreases were used in the development of these perfusion models. Pancreases underwent 24 h of static cold storage (SCS, n = 3) and then viability assessment on an isolated oxygenated normothermic reperfusion (NRP) circuit or 24-h SCS, 5 h of HMP, and then NRP (SCS-HMP, n = 3). Human pancreases (n = 3) were used in the development of a preclinical model. Porcine HMP demonstrated stable perfusion indices at low pressures, with a weight gain of between 15.3% and 27.6%. During NRP, SCS-HMP pancreases demonstrated stable perfusion flow indices (PFIs) throughout reperfusion (area under the curve was in the range of 0.49-2.04 mL/min/100 g/mm Hg), whereas SCS-only pancreases had deteriorating PFI with a decline of between 19% and 46%. Human pancreas models demonstrated stable PFI between 0.18 and 0.69 mL/min/100 g/mm Hg during HMP with weight gain of between 3.9% and 14.7%. NRP perfusion in porcine and human models was stable, and functional assessment via insulin secretion demonstrated beta cell viability. Exocrine function was intact with production of pancreatic secretions only in human grafts. Application of machine perfusion in preclinical porcine and human pancreas models is feasible and successful; the development of these translational models could be beneficial in improving pancreas preservation before transplantation and allowing organ viability assessment and optimization.