Liraglutide enhances the efficacy of human mesenchymal stem cells in preserving islet β-cell function in severe non-obese diabetic mice

Abstract

Glucagon-like peptide 1 (GLP-1) can promote islet β cell replication and function, and mesenchymal stem cells (MSCs) can inhibit T cell autoimmunity. The aim of this study was to test the dynamic distribution of infused human MSCs and the therapeutic effect of combined MSCs and liraglutide, a long-acting GLP-1 analog, on preserving β cell function in severe nonobese diabetic (NOD) mice. We found that infused MSCs accumulated in the pancreas at 4 wks post infusion, which was not affected by liraglutide treatment. Liraglutide significantly enhanced the function of MSCs to preserve islet β cells by reducing glucose levels 30 min post glucose challenge and increasing the content and secretion of insulin by islet β cells in severely diabetic mice. Infusion with MSCs significantly reduced insulitis scores but increased the frequency of splenic Tregs, accompanied by a reduction in plasma IFN-γ and TNF-α levels and an elevation of plasma IL-10 and transforming growth factor-β1 (TGF-β1) levels in NOD mice. Although liraglutide mitigated MSC-mediated changes in the frequency of Tregs and the level of plasma IL-10, it significantly increased the plasma TGF-β1 levels in severely diabetic mice. Therefore, our findings suggest that liraglutide could enhance the therapeutic efficacy of MSCs in the treatment of severe type 1 diabetes.