Transplantation of mesenchymal stem cells improves type 1 diabetes mellitus.

Bone-marrow-derived stem cells can regenerate pancreatic tissue in a model of type 1 diabetes mellitus. Mesenchymal stem cells (MSCs) form the main part of bone marrow. We show that the intrapancreatic transplantation of MSCs elevates serum insulin and C-peptide, while decreasing blood glucose. MSCs engrafted into the damaged rat pancreas become distributed into the blood vessels, acini, ducts, and islets. Renascent islets, islet-like clusters, and a small number of MSCs expressing insulin protein have been observed in the pancreas of diabetic rats. Intrapancreatic transplantation of MSCs triggers a series of molecular and cellular events, including differentiation towards the pancreas directly and the provision of a niche to start endogenous pancreatic regeneration, which ameliorates hypoinsulinemia and hyperglycemia caused by streptozotocin. These data establish the many roles of MSCs in the restoration of the function of an injured organ.