Cryopreserved Agarose-Encapsulated Islets As Bioartificial Pancreas: A Feasibility Study

Background. A bioartificial Pancreas in which islets of Langerhans (islets) are encapsulated within a semipermeable membrane, such as agrose, has been proposed for treating type I diabetic mellitus. However, the long-term storage for providing a convenient and easily accessible supply still remains all issue. We investigated cryopreservation Lis a potential method of long-term storage for agarose-encapsulated islets (Mic-islets). Methods. The morphology, insulin secretion, and histochemical staining of cryopreserved Mic-islets were analyzed. Streptozotocin-induced diabetic mice were transplanted intraperitoneally with 1000, 2000, and 3000 Mic-islets after cryopreservation in KYO-1 vitrification solution. Blood glucose levels were Measured and immunohistochemical analyses were performed at 41 days posttransplantation. Results. Transplanted cryopreserved Mic-islets restored normoglycemia in diabetic mice. The mean (+/- SD) normoglycemic periods were 32.0 +/- 13.2 days and 46.3 +/- 13.3 days for recipients of 1000 (n=5) and 2000 (n=4) cryopreserved Mic-islets, respectively, whereas the mean normoglycemic period was 53.2 +/- 16.7 days for recipients of 1000 noncryopreserved Mic-islets (n=7). These data indicate that cryopreserved Mic-islets transplanted as a bioartificial pancreas successfully controlled blood glucose levels for extended periods. Conclusion. Cryopreserved agarose-encapsulated islets Could successfully Control the blood glucose level for a long period as a bioartificial pancreas.