TREHALOSE - A CRYOPROTECTANT THAT ENHANCES RECOVERY AND PRESERVES FUNCTION OF HUMAN PANCREATIC-ISLETS AFTER LONG-TERM STORAGE

The scarcity of available tissue for transplantation in diabetes and t he need for multiple donors make it mandatory to use an optimal cryopr eservation method that allows maximal recovery and preservation of bet a-cell function, We have developed a method to cryopreserve islets wit h excellent survival of endocrine cells, Current methods use DMSO as c ryoprotectant. Our method involves introducing both DMSO and the disac charide trehalose into the cells during cooling. Uptake and release of trehalose occurred during the thermotropic lipid-phase transition mea sured in pancreatic endocrine cells between 5 degrees and 9 degrees C, using [C-14]trehalose, Recovery of adult islets after cryopreservatio n with 300 mmol/l trehalose was 92 vs. 58% using DMSO alone, In vitro function, in terms of insulin content and release in response to secre tagogues, was indistinguishable from fresh islets, Grafts from islets cryopreserved with trehalose contained 14-fold more insulin than graft s from islets cryopreserved without trehalose, Results with human feta l islet-like cell clusters (ICCs) were more pronounced: recovery from cryopreservation was 94%, compared with 42% without trehalose, Complet e functionality of fetal cells was also restored; tritiated thymidine incorporation and insulin content and release were similar to fresh ti ssue, After transplantation in nude mice, there was a 15-fold increase in insulin content of grafts from ICCs cryopreserved with trehalose c ompared with ICCs cryopreserved without trehalose, Thus, the addition of trehalose to cryopreservation protocols leads to previously unobtai nable survival rates of human pancreatic endocrine tissue.