Improvement of canine islet yield by donor pancreas infusion with a p38MAPK inhibitor

Background. The activation of p38 mitogen-activated protein kinases (MAPK) is implicated in cold ischemia-reperfusion injury of donor organs. The islet isolation process, from pancreas procurement through islet collection, may activate p38MAPK leading to cytokine release and islet damage. This damage may be prevented by treating pancreata with a p38MAPK inhibitor (p381H) before cold preservation. Methods. Pancreata removed from Beagle dogs were infused with University of Wisconsin solution containing the p38IH, SB203580, and Pefabloc (n=6) or vehicle (dimethyl sulfoxide and Pefabloc) alone (n=7), through the pancreatic duct and preserved using the two-layer method. After 20 to 22 hr, islets were isolated and 3000 IEQ/kg were autotransplanted into the corresponding dog to monitor glucose metabolism. Results. p38IH-treated pancreata yielded significantly more islets than control pancreata (IEQ/g: 2134 +/- 297 vs. 1477 +/- 145 IEQ/g or 65,012 +/- 9385 vs. 45,700 +/- 5103 IEQ/pancreas; P<0.05). Apoptotic beta-cell percentages assessed by laser scanning cytometry were lower in p38IH-treated than the controls (44%+/- 9.4% vs. 61.6%+/- 4.8%, P<0.05). Tumor necrosis factor-a expression assessed by real-time reverse transcription polymerase chain reaction was significantly lower in the p38IH-treated group than controls. All dogs (3000 IEQ/kg) transplanted with p38IH-treated islets (n= 5) became euglycemic versus four of five dogs that received untreated islets. Plasma C-peptide levels after glucagon challenge were higher in animals receiving p381H-treated islets (n=5) versus untreated islets (n=4) (0.40 +/- 0.78 vs. 0.21 +/- 0.05 ng/mL, P<0.05). Conclusions. Infusion of pancreata with University of Wisconsin solution containing p38IH through the duct before preservation suppresses cytokine release, prevents beta-cell apoptosis, and improves islet yield significantly with no adverse effect on islet function after transplantation. p38IH treatment of human pancreata may improve islet yield for use in clinical transplantation.