Islet encapsulation to treat diabetes

Islet transplantation using the Edmonton Protocol has provided new hope for a cure for diabetes. Widespread access to this treatment would require large numbers of insulin-secreting beta cells and improved methods to avoid graft rejection. One strategy to reduce graft rejection is to place the islets inside an immunoisolation device (for example via encapsulation) that creates a physical barrier between the graft and components of the host immune system. Islet encapsulation in hydrogel beads has allowed long-term islet survival and reversal of autoimmune diabetes in non-immunosuppressed rodents. Although clinical trials in humans are ongoing, the promising results obtained in rodents have not been replicated in primates. We have developed novel emulsion- and microchannel-based methods to microencapsulate large amounts of islets within a few minutes. This new type of uncoated alginate bead could avoid issues such as fibrotic overgrowth encountered with other encapsulation technologies. Additionally, we are exploring strategies for creating vascularized macroencapsulation devices to improve oxygen and nutrient transfer within thicker grafts.