Clinical Benefit of Islet Xenotransplantation for the Treatment of Type 1 Diabetes

BACKGROUND: Allogeneic islet transplantation has become a viable option for the treatment of unstable type 1 diabetes. However, the donor shortage and the necessity of the immunosuppressive drugs are two major issues. To solve these issues, we performed islet xenotransplantation using encapsulated neonatal porcine islets without immunosuppressive drugs. METHODS: Two different doses (approximately 5000 IEQ/kg and 10,000 IEQ/kg) of encapsulated neonatal porcine islets were transplanted twice (total approximately 10,000 IEQ/kg and 20,000 IEQ/kg) into four type 1 diabetic patients in each group (total 8 patients). FINDINGS: In the higher dose group, all four patients improved HbA1c. This was maintained at a level of < 7% for > 600 days with significant reduction of the frequency of unaware hypoglycemic events. INTERPRETATION: The clinical benefit of islet xenotransplantation with microencapsulation has been shown.