Promoting pro-endocrine differentiation and graft maturation following surgical resection of the mouse pancreas

Type 1 diabetes (T1D) is an autoimmune disease, where insulin-producing β-cells in the pancreas are inappropriately recognized and destroyed by immune cells. Islet transplantation is the most successful cell-based therapy for T1D individuals who experience frequent and severe life-threatening hypoglycemia. However, this therapy is extremely restricted owing to the limited availability of donor pancreas. In recent years, significant progress has been made in generating β-cells from stem/progenitor cells using different approaches of in vitro differentiation. The insulin production from such in vitro generated β-cells is still far less than that observed in islet β-cells. We employed a novel strategy to improve the efficiency of progenitor cell differentiation by performing partial mouse pancreas resection after transplanting in vitro generated insulin-producing cells under the kidney capsule of these mice. Pancreas resection (pancreatectomy) has been shown to induce regenerative pathways, leading to regeneration of almost the entire resected pancreas over 3–5 weeks in mice. We found that in our method, regenerating mouse pancreas promotes better graft differentiation/maturation and insulin production from transplanted cells. In this chapter, we detail the protocols used for transplantation of in vitro differentiated cells in immunocompromised mice, partial pancreatectomy in host (NOD scid) mice, and assessment of graft function. We believe that our protocols provide a solid platform for further studies aimed at understanding growth/differentiation molecules secreted from regenerating pancreas that promote graft maturation.