Background: Pancreatic islet transplantation is the milestone therapy to restore glucose homeostasis in type 1 diabetes. Despite advances in surgical techniques, patients in low and middle income countries do not have access to islet transplantation due to the steep cost of islet extraction. High quality islet isolation is the bottleneck because the standard enzymatic digestion method is too costly. Here we hypothesize that flash frozen pancreata still contain intact GLUT2 in endocrine islets.

Material and Method: We demonstrate that glucose sensitivity method of islet isolation from cryopreserved tissues of porcine and human pancreata results in functional islets. Islets were isolated based on the property of GLUT2 transporter in islets that enable glucose transport across the cell membrane. Minced pancreatic fresh or frozen tissues were incubated for 20 minutes in media supplemented with 600 mM glucose. After that, the medium was replaced with zero-glucose medium. We tested islet quality by immunostaining hormone contents, Glut2 receptor, and measuring insulin secretion using glucose induced insulin secretion assay. Importantly, islet isolated from frozen tissues showed ability to secrete insulin in response to glucose stimulation similar to freshly isolated islets. These isolation and purification method applied to cryopreserved tissues is much simpler and selective for functional islets.

Results: By omitting the enzymatic digestion step, this results more than 90% cost reduction in islet isolation and purification method.

Conclusion: These data bring about islet transplantation feasibility and accessibility to many more patients.

Keywords: Diabetes, Islet, Islet isolation, Transplantation