Transplantation of microcapsules with insulin-producing porcine islet cells for use in Type 1 diabetes.
- Improved engineering of microcapsules prevents immune activation and microcapsule rejection.
- Encapsulated islet cells sense blood glucose levels and secrete insulin.
- Transplanted microcapsules demonstrate a long-term function for normalizing blood glucose levels.
Annually, over 15,000 individuals are diagnosed with Type 1 diabetes in the US. The prevalence of Type 1 diabetes is over 215,000 individuals in the US alone. Patients with Type 1 diabetes account for about 10% of all diabetic cases. There is no cure for diabetes. For survival, Type 1 diabetic patients need a life-long delivery of insulin using either injections or insulin-releasing pumps. In the US, medical costs for treating Type 1 diabetes are estimated to be over 10 billion dollars annually. Transplantation of insulin-producing pancreatic islet cells that can evade immune system-induced rejection is likely to deliver a cure to Type 1 diabetic patients.
Successful treatment of Type 1 diabetes requires transplantation of functional islet cells combined with a lifelong application of immunosuppression therapy. The scarcity of donor islet cells and complications from immunosuppression are major obstacles in treating Type 1 diabetes. An alternative treatment, such as transplantation of abundantly available insulin-producing porcine islet cells, could achieve prolonged normalization of blood glucose levels in Type 1 diabetes if the cells are protected from the host's immune system activation. The inventor at Emory University has designed durable, immune tolerance-inducing microcapsules that provide long-term survival of porcine islet cells in mouse models of Type 1 diabetes. The unique microcapsule design allows the islet cells to sense blood glucose levels and produce insulin while simultaneously being protected from the host's immune effector functions. The walls of the microcapsules are designed to prevent host immune cells and immunoglobulins from reaching the islet cells. Additionally, the microcapsules release antagonists that suppress T cell-mediated cytotoxicity against islet cells. In vivo studies with the transplanted microcapsules demonstrate a long-term (>466 days) normalization of blood glucose levels and absence of immune rejection of the microcapsules in a mouse model of Type1 diabetes.
In vitro and in vivo data confirm the effectiveness of microcapsules in the absence of immune rejection. The effectiveness of microcapsules in non-human primates in vivo is being tested.