Liraglutide Enhances the Efficacy of Human Mesenchymal Stem Cells in Preserving Islet ß-cell Function in Severe Non-obese Diabetic Mice.

Glucagon-like peptide 1 (GLP-1) can promote islet ß-cell replication and function, and mesenchymal stem cells (MSCs) can inhibit T cell autoimmunity. This study aimed at testing the dynamic distribution of infused human MSCs and therapeutic effect of combined MSCs and Liraglutide, a long-acting GLP-1 analogue, on preserving ß-cell function in severe non-obese diabetic (NOD) mice. We found that infused MSCs accumulated in the pancreas at 4 weeks post infusion, which was not affected by Liraglutide treatment. Liraglutide significantly enhanced the function of MSCs to preserve islet ß-cells by reducing glucose level at 30 minutes post glucose challenge and increasing the contents and secretion of insulin by islet ß-cells in severe diabetic NOD mice. Infusion with MSCs significantly reduced insulitis scores, but increased the frequency of splenic Tregs, accompanied by reducing the levels of plasma IFN-γ and TNF-α and elevating the levels of plasma IL-10 and transforming growth factor-ß1 (TGF-ß1) in NOD mice. Although Liraglutide mitigated MSC-mediated changes in the frequency of Tregs and the levels of plasma IL-10, Liraglutide significantly increased the levels of plasma TGF-ß1 in severe diabetic NOD mice. Therefore, our findings suggest that Liraglutide may enhance the therapeutic efficacy of MSCs in treatment of severe type 1 diabetes.

[Extracellular polymeric substances disintegration by Fenton oxidation of excess sludge].

Fenton oxidation was used to disintegrate extracellular polymeric substances (EPS) of excess sludge with its strong oxidation ability. The concentration of polysaccharide, protein and the change of soluble chemical oxygen demand (SCOD) disintegrated from EPS represent the EPS disintegration degree. The objective of this study is to optimize the operational conditions for EPS disintegration with Fenton oxidation. It is shown that the optimal operational condition is as following: pH = 2.5, reaction time = 90 min, H2O2/Fe2+ (weight dosage ratio) = 8:1 and reaction temperature is about 65-70 degrees C. Under this condition after the Fenton oxidation, SCOD, concentration of polysaccharide, protein in the supernate increase from 45.88, 10.96 and 11.99 mg x L(-1) to 684.93, 382.17 and 302.62 mg x L(-1), respectively; the average diameter and the median diameter of sludge particulates reduce from 838.89 microm and 859.20 microm to 137.22 microm and 148.69 microm, respectively. As a result, EPS is effectively disintegrated by Fenton oxidation and the sludge is greatly mineralized, which benefits the further sludge reduction and utilization.