Preservation of pancreatic islets in cold UW solution before transplantation

Abstract

Culture of islets prior to transplantation needs to be revisited for maintaining functional islet capacity. This study was conducted to compare cold UW (University of Wisconsin) preservation with conventional culture based on insulin secretory capacity in vitro and in vivo. Islets isolated from Wistar rats were either cultured for 24 h at 37°C in RPMI1640 medium or DMEM containing various concentrations of glucose or preserved for the same period in UW solution or in DMEM solution at 4°C. The islet yield in UW group, but not in other groups, was maintained as comparable with that of fresh islets. Insulin secretory capacity in response to glucose was maintained only in the islets of UW group, but not in other groups. SCID mice given 300 IEQ islets of UW group showed gradual restoration of normoglycemia as found in the mice given freshly isolated islets. Meanwhile, those mice given cultured islets for 24 h at 37°C in RPMI1640 medium showed rapid decrease of blood glucose levels on day 1 followed by relatively elevated levels on day 2, suggesting unstable insulin secretory capacity of islets. Morphological staining with anti-HMGB1 (high mobility group B1) antibody revealed central damage of islets in all culture groups regardless of glucose concentration and in islets of cold DMEM group, whereas those in the UW group were quite intact. These results suggest that cold preservation in UW solution is simple and beneficial in protecting islets morphologically and functionally before transplantation.

Keywords: UW solution; apoptosis; culture; cytoprotection; high mobility group B1; insulin secretion; islet preservation.