Mesenchymal Stem Cells Contribute to Insulin-Producing Cells Upon Microenvironmental Manipulation In Vitro

Abstract: Background: Extracellular microenvironment and intrinsic genetic programs determine the fate of stem cells. We observed whether mesenchymal stem cells (MSCs) contributed to insulin-producing cells in a manipulated microenvironment. Methods: We delivered pancreatic pieces into Niobium-Coated Dynamatrix to construct a simulated pancreatic microenvironment, upon which soluble cytokine exchange and direct cell–cell contact between MSCs and pancreatic cells could occur. Bone marrow–derived MSCs were cultured upon the microenvironment. Differentiated isletlike cells were observed under an inverted microscope. Insulin in supernates was measurement by enzyme-linked immunosorbent assay. Insulin and c-peptide expression were verified by fluorescent immunocytochemistry and fluorescence in situ hybridization. Apoptosis of isletlike masses in high-glucose DMEM was detected by FACS. Results: After 3 to 4 weeks in culture, typical isletlike masses were observed. Insulin secreted by differentiated cells (414.47 ± 30.30 mIU/L) was much greater than that of undifferentiated cells (4.89 ± 1.01 mIU/L; P < .05). Insulin and c-peptide expression were positive both in protein and mRNA levels. The transdifferentiated isletlike mass did not undergo apoptosis after another 3 weeks of culture in high-glucose DMEM. Conclusion: This simulated injury microenvironment without induction guided MSCs to functional isletlike cells hopefully to replace β cells. [Copyright &y& Elsevier]