Background: Pancreatic islet transplantation is a promising cell-based therapy for type 1 diabetes (insulin-dependent diabetes mellitus), a disease triggered by the immune response against autoantigens of beta-cells. However, the recurrence of immune response after transplantation and the diabetogenic and growth-stunting side effects of immunosuppressants are major challenges to the application of islet transplantation. Mesenchymal stem cells (MSCs) have recently been reported to modulate the immune response in allogeneic transplantation.
Methods: The ability of MSCs, either syngeneic or allogeneic to recipients, to prevent acute rejection and improve glycemic control was investigated in rats with diabetes given a marginal mass of pancreatic islets through the portal vein.
Results: Reduced glucose levels and low-grade rejections were observed up to 15 days after transplantation upon triple-dose administration of MSCs, indicating that MSCs prolong graft function by preventing acute rejection. The efficacy of MSCs was associated with a reduction of pro-inflammatory cytokines and was independent of the administration route. Efficacy was similar for MSCs whether syngeneic or allogeneic to recipients and comparable to that of immunosuppressive therapy.
Conclusions: The results show that MSCs modulate the immune response through a down-regulation of pro-inflammatory cytokines, suggesting that MSCs may prevent acute rejection and improve graft function in portal vein pancreatic islet transplantation.