The use of an approved biodegradable polymer scaffold as a solid support system for improvement of islet engraftment

The aim of this study was to investigate whether the use of a medically approved biodegradable scaffold as a solid support system would enhance graft survival following transplantation into the omental pouch in a preclinical large animal model. Six beagle dogs underwent total pancreatectomy followed by islet autotransplantation into the omental pouch. Four dogs received islets seeded in a biodegradable polymer scaffold and two received free islets without a scaffold. All four animals that received islets in the scaffold became normoglycemic without exogeneous insulin injection. One dog, transplanted with the largest number of islets, maintained a normal metabolic state until the graft was removed at 5 months posttransplant. In two out of the three that received a marginal islet mass, insulin independence was sustained up to 2 months. In contrast, two dogs transplanted with a similar marginal mass without the scaffold never became normoglycemic. Histological examination of the grafts in the scaffold showed numerous well-granulated, insulin-containing cells as well as glucagon-positive cells. These results indicate that biodegradable scaffolds may enhance survival and function of islet grafts. Manipulation of the microenvironment of transplanted islets may constitute the basis for new approaches to enhance islet engraftment.