Experimental Islet Isolation in Porcine Pancreas with New Enzyme Liberase PI

Kim, Song Cheol; Kim, Yeon Cheol; Han, Duck Jong; Hering, Bernhard J

Abstract

PURPOSE: Transplantation of pancreas islet cell has been demonstrated to be able to cure for type I diabetes. It can offer not only discontinuation of insulin but also preventing of complications from diabetes. However mismatching between human donors and recipients for viable pancreas has restricted the enormous potential of pancreas islet cell transplantation. Porcine islets can be the best source of xenotransplantation of islets that can overcome the donor shortage. Aim of this study is to investigate the results from consecutive 20 porcine islet isolation using new enzyme Liberase PI.
METHODS
Twenty pancreata were procured for islet isolation. Islet isolation was done with modified Ricordi's method using new brand enzyme liberase PI. Quantitaion of islet, viability staining, insulin stimulation assay, intracellular insulin content/ DNA assay and in vivo transplantation into diabetic nude mice were done for quality control of islets. These results were compared between high-yield group (>2,500 IEQ/gram of pancreas) and low-yield group (<2,500 IEQ/gram of pancreas).
RESULTS
Sufficient amount of purified islets (3,000 IEQ/gram of pancreas) were obtained using new brand enzyme Liberase PI. These islets showed good quality in structure and functions, which were demonstrated by in vitro and in vivo standard assay. Isolation index (IEQ/number) of low-yield group was lower than that of high-yield group (0.75 vs. 0.86), which means more fragmentation of islets in low-yield group. There were no differences in function between two groups.
CONCLUSION
We were able to obtain sufficient number of viable, functional islets from porcine pancreas using new brand enzyme Liberase PI and low temperature isolation technique. However, overdigestion of islets during the isolation has remained to be overcome. Advance in porcine islet isolation technique will make the islet xenotransplantation in pig in reality for cure of diabetes mellitus in the future.