Insulin-producing cells derived from adult human bone marrow mesenchymal stem cells control streptozotocin-induced diabetes in nude mice

M. Gabr¹, M. Zakaria¹, A. Refaie¹, A. Mostafa¹, M. Abou-El-Mahasen¹, S. Ashamallah¹, S. Khater¹, S. El-Halawani¹, R. Ibrahim¹, G. Shu Uin², M. Kloc³, A. Clark⁴, R. Calne⁵, M. Ghoneim^1
1 Urology & Nephrology Center, Mansoura, Egypt; ² Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore; ³ The Methodist Hospital Research Institute,, Houston, Texas, USA; ⁴ Oxford Center for Diabetes, Endocrinology and Metabolism, Oxford, U.K.; ⁵ Cambridge University, Cambridge, U.K.

Background: Harvesting, expansion and directed differentiation of human bone marrow-derived mesenchymal stem cells (MSCs) would provide an autologous source of surrogate β-cells that alleviate the limitations of availability and/or allogenic rejection following pancreatic or islet transplantation.

Methods: Bone marrow cells were obtained from three adult type II diabetic volunteers and 3 non-diabetic donors. After 3 days in culture; adherent MSCs were expanded for 2 passages. At passage 3, differentiation was carried out in a 3-staged procedure. Cells were cultured in a glucose-rich medium containing several activation and growth factors. These cells were evaluated in-vitro by immunofluoresce,electron microscopy and Rt-PCR. Insulin and c-peptide release in response to increasing glucose concentrations was determined.

Results: By immunofluorescence, some cells tested positively for insulin, c-peptide and glucagon with co-expression of insulin and c-peptide by the same cells. Nanogold immunostaining for electron microscopy demonstrated the presence of c-peptide at the rough endoplasmic reticulum. These insulin-producing cells (IPCs), expressed a variety of transcription factors and genes of pancreatic hormones closely similar to those of pancreatic islets. There was a stepwise increase in insulin and c-peptide release by these cells in response to increasing glucose concentrations. One thousand clusters inserted under the renal capsule of diabetic nude mice resulted in control of their diabetic status for 3 months. The sera of treated mice contained human insulin, human c-peptide but negligible levels of mouse insulin. When the IPCs-bearing kidneys were removed, rapid return of diabetic state was noted. Histology of the removed kidneys showed insulin staining cells under the capsule.

Conclusion: MSCs could be differentiated to form IPCs. The implanted IPCs could control diabetic nude mice and maintain their euglycaemic state for 3 months. Optimization of the culture conditions and/or the differentiation techniques are needed to improve the functional performance of these cells.