Developing a robust native extracellular matrix to improve islet function with attenuated immunogenicity for transplantation

Project Summary/Abstract Compared to daily multiple insulin injections, pancreatic islet transplantation for type 1 diabetes (loss of β-cells) or the latter stages of type 2 diabetes (β-cells fail to produce sufficient insulin) provides a near physiologic regulation of normal blood glucose levels and significantly improves quality of life by minimizing severe hypoglycemia and diabetic complications. However, a shortage of donors, loss of allograft function over time, and the need for lifelong immunosuppression must be resolved before this approach can be widely adopted. The overall goal of this proposal is to improve islet transplantation using a native extracellular matrix (ECM)- based culture system, which mimics the pancreatic microenvironment, to obtain large quantities of high-quality islets with attenuated immunogenicity. Previously, we reported that culture of rat pancreatic islets on native ECM, produced by bone marrow stromal cells, promoted growth of islet vascular endothelial cells (VECs), production of islet-bm associated proteins, improvement of β- cell function, and attenuation of islet immunogenicity (Appendix 1). Recently, we developed an ECM synthesized by human amniotic fluid (AF)-derived pluripotent stem cells. Proteomic analysis suggested that the protein composition of AF-ECM and pancreatic ECM were similar and this was validated in our preliminary studies. Moreover, human islets maintained on AF-ECM showed significantly improved insulin secretion in response to glucose stimulation. Here, we propose to explore AF-ECM, a surrogate pancreatic-like ECM (pI-ECM), for potential use in maintaining human islets. We will prepare pl-ECM employing Good Manufacturing Practices (GMP) and hypothesize that maintenance of islets on pl-ECM, prepared using GMP compliant conditions, will facilitate the recovery of large numbers of high-quality human islets with decreased immunogenicity. To test this hypothesis, we will manufacture pl-ECM with reagents and facilities that are GMP compliant and then compare its architecture, mechanical properties, and protein composition with our current research use only (RUO) version (Aim 1). We will also compare the viability, function and immunogenicity of human islets maintained on GMP-compliant versus RUO- pl-ECM (Aims 2and3). If the proposed work is successful, it will provide the necessary preliminary data and rationale for moving forward with a small-scale clinical trial and commercialize a new, GMP-grade version of our matrix product for use in the manufacture of cell products for clinical applications.