A new preservation solution increases islet yield and reduces graft immunogenicity in pancreatic islet transplantation

The aim of the study was to test a new preservation solution containing polyethylene glycol (S.C.O.T. solution) as pancreatic islet isolation medium both to increase the islet yield and to prolong the allograft survival. In a model of islet transplantation in diabetic mouse, islets were isolated with S.C.O.T. in experimental groups and with Hank's balanced salt solution (HBSS) in control groups. The use of S.C.O.T. solution improved the islet yield (596+/-27 IEQ/pancreas) as compared to HBSS (456+/-11 IEQ/pancreas) (P<0.001). Allograft survival was prolonged in experimental group (17.3+/-4.3 days) versus controls (7.3+/-3.6 days) in a full mismatch combination (P<0.001) and in absence of recipient immunosuppression. The same prolongation (10 days) was also found in a strongly alloreactive transgenic combination. It is hypothesized that a transitory phenomenon of immunocamouflage of the graft surface antigens occurs, as shown by immunofluorescence studies. The use of this new solution could improve the results of islet transplantation in humans.