Tissue engineering a pancreatic substitute based on recombinant intestinal endocrine cells

Abstract

Cell-based treatments for insulin-dependent diabetes (IDD) may provide more physiologic regulation of blood glucose levels than daily insulin injections, thereby reducing the occurrence of secondary complication associated with IDD. An autologous cell source is especially attractive for regulatory and ethical reasons and for circumventing the need for immunosuppression, which is currently standard for islet transplantation. Our approach focuses on using adult non-β-cells engineered for physiologic insulin secretion. Specifically, we utilize enteroendocrine L-cells, which naturally exhibit regulated secretion of GLP-1 in response to physiologic stimuli, and upon genetic engineering, co-secrete insulin in a regulated manner. The overall goal of this project is to develop a tissue engineered pancreatic substitute based on a recombinant enteroendocrine cell line and test the efficacy of the pancreatic substitute by implantation into diabetic mice. The specific aims of this thesis were to (1) to modify murine L-cells for regulated insulin secretion and evaluate the insulin secretion properties of the recombinant cells; (2) to incorporate insulin-secreting L-cells into an implantable construct containing small intestinal submucosa (SIS) and to evaluate insulin secretion from the construct in vitro; and (3) to test the efficacy of the tissue engineered pancreatic substitute in vivo by implanting it intraperitoneally in mice made diabetic by streptozotocin. Thus, this proposal takes a tissue engineered pancreatic substitute for IDD from in vitro development to in vivo testing.