differentiation of human embryonic stem cells into insulin- secreting cells

introduction: type i diabetes mellitus is caused by autoimmune destruction of the insulin-producing β-cells. a new potential method for curing the disease is transplantation of differentiated insulin- secreting cells from human embryonic stem cells. methods: human embryonic stem cell lines (royan h1) were used to produce embryoid bodies. differentiation carried out by growth factor-mediated selection of nestin positive cells. in final stage, these cells were expanded in the presence of bfgf, followed by addition of nicotinamide to promote differentiation of insulin- secreting cells. cells were assayed by immunocytochemistry, rt-pcr, insulin secreting assay with radio-immuno assay kit and transmission electron microscopy. the cells were transplanted into immunosuppressed mice. results: analysis of differentiation cells immunocytochemistry showed that these cells were insulin, glucagon, somatostatin and pancreatic polypeptide positive. rt-pcr reaction demonstrated the expression of pancreatic endocrine genes. differentiation cells secreted insulin in response to glucose, but no significance difference in insulin concentration was observed with an increase in concentration of glucose. the implanted cells were vascularized and remained immunoreactive with insulin and glucagon. transmission electron microscopy of differentiate cells showed golgi complexes, rough endoplasmic reticulum and a few granules but no true β granules. conclusion: the data showed that human embryonic stem cells can produce insulin secreting cells. however, more studies are needed to generate true beta cells.