Growth of MIN-6 Cells on Salmon Fibrinogen Scaffold Improves Insulin Secretion

Differentiation of Wharton's Jelly-derived mesenchymal stem cells into insulin-producing beta cells with the enhanced functional level on electrospun PRP-PVP-PCL/PCL fiber scaffold

Diabetes is a global problem that threatens human health. Cell therapy methods using stem cells, and tissue engineering of pancreatic islets as new therapeutic approaches have increased the chances of successful diabetes treatment. In this study, to differentiate Wharton's Jelly-derived mesenchymal stem cells (WJ-MSCs) into insulin-producing cells (IPCs) with improved maturity, and function, platelet-rich plasma (PRP)-Polyvinylpyrrolidone (PVP)-Polycaprolactone (PCL)/PCL scaffold was designed. The two-dimensional (2D) control group included cell culture without differentiation medium, and the experimental groups included 2D, and three-dimensional (3D) groups with pancreatic beta cell differentiation medium. WJ-MSCs-derived IPCs on PRP-PVP-PCL/PCL scaffold took round cluster morphology, the typical pancreatic islets morphology. Real-time PCR, immunocytochemistry, and flowcytometry data showed a significant increase in pancreatic marker genes in WJ-MSCs-derived IPCs on the PRP-PVP-PCL/PCL scaffold compared to the 2D-experimental group. Also, using the ELISA assay, a significant increase in the secretion of insulin, and C-peptide was measured in the WJ-MSCs-derived IPCs of the 3D-experimental group compared to the 2D experimental group, the highest amount of insulin (38 µlU/ml), and C-peptide (43 pmol/l) secretion was in the 3D experimental group, and in response to 25 mM glucose solution, which indicated a significant improvement in the functional level of the WJ-MSCs-derived IPCs in the 3D group. The results showed that the PRP-PVP-PCL/PCL scaffold can provide an appropriate microenvironment for the engineering of pancreatic islets, and the generation of IPCs.

Optimal temperature for the long-term culture of adult porcine islets for xenotransplantation

Porcine islet xenotransplantation represents a promising therapy for severe diabetes mellitus. Long-term culture of porcine islets is a crucial challenge to permit the on-demand provision of islets. We aimed to identify the optimal temperature for the long-term culture of adult porcine islets for xenotransplantation. We evaluated the factors potentially influencing successful 28-day culture of islets at 24°C and 37°C, and found that culture at 37°C contributed to the stability of the morphology of the islets, the proliferation of islet cells, and the recovery of endocrine function, indicated by the expression of genes involved in pancreatic development, hormone production, and glucose-stimulated insulin secretion. These advantages may be provided by islet-derived CD146-positive stellate cells. The efficacy of xenotransplantation using islets cultured for a long time at 37°C was similar to that of overnight-cultured islets. In conclusion, 37°C might be a suitable temperature for the long-term culture of porcine islets, but further modifications will be required for successful xenotransplantation in a clinical setting.