Encapsulated cells to treat type 1 diabetes

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DESCRIPTION (provided by applicant): Encapsulation of genetically modified cells permits insulin delivery for Type 1 diabetes without the need for immunosuppression. Diabetes mellitus requires tight blood glucose control to delay or prevent the onset of late complications. The encapsulation must permit the exchange of nutrients to sustain cell viability, and allow insulin to efflux, but shield cells from immune attack. Using Theracyte immunoisolation devices, we encapsulated vascular smooth muscle cells (VSMC) transduced to express rat erythropoietin (EPO) and transplanted them into allergenic recipient rats. Hematocrits increased by up to 75% and remained high for up to 2 years. Importantly, after Theracyte devices were removed and new ones implanted sustained increased hematocrits were again achieved. Thus, Theracyte devices can sustain cells, protect allogeneic cells from immune attack, and allow second implants. In the first aim we propose to use encapsulated VSMC transduced to express glucose-regulated insulin to treat diabetic rats. VSMC multiply transduced to express glucose-regulated insulin will be cloned and seeded in Theracyte devices and implanted in diabetic rats. In a second aim we will study genetically modified islets implanted in diabetic rats using Theracyte devices. Diabetic rats will receive encapsulation devices seeded with allogeneic rat islets genetically modified with lentivirus vector encoding Bcl-2 to prevent apoptosis and co-seeded with VSMC transduced to express glucagon like peptide-1 (GLP-1) or EPO to expand their function and therapeutic lifetime. We will also co-seed islets with transduced cloned VSMC expressing glucose-regulated insulin generated in aim 1. The long term goals of this proposal are (1) to develop cloned, well characterized cell lines that may be transplanted to treat rats with diabetes and (2) to develop methods to permit implantation of allogeneic islets for long term survival and therapy without the need for immunosuppression. This approach has the benefit that only one human cell line will be generated and characterized for the treatment of all patients. These studies will provide valuable preclinical information from diabetic rodents that may be applied to treat patients with type 1 diabetes.