Three-Dimensional Vascularized Structure for Bioartificial Pancreas

The proposed project will improve the existing methodologies to protect non-human pancreatic islets from the immunologically-different host. Encapsulating the living islets in a protective membrane would allow insulin to be secreted, yet prevent the immune system from rejecting the islet. The lack of success of such transplanted islets inside the peritoneal cavity is now considered to be due to poor vascularization of the implant. The absence of fibrotic growth, leading to a necrotic zone within the islets. The objective of this proposal is to test a hypothesis that vascularization and angiogenesis can be induces by means of addition of proper angiogenic factors embedded within a polymeric bead or a polymeric coating. The angiogenesis would be sustained over a longer period of time, depending on the release characteristics of the polymer matrix. A biocompatible mesh or perforated tubular material will be applied as a resident material for microcapsules eventually bearing islets. It is anticipated that blood capillaries will be generated outside the capsules and will penetrate through the implant openings and ingrow into the vicinity of capsules/islets. The extent of angiogenesis will be determined via histology and immunochemistry.