Bckground Stem cells,which have the ability to differentiate into insulin-producing cells (IPCs),would provide apotentially unlimited source of islet cells for transplantation and alleviate the major limitations of availability and allogeneicrejection.Therefore,the utilization of stem cells is becoming the most promising therapy for diabetes mellitus (DM).Here,we studied the differentiation capacity of the diabetic patient’s bone marrow-derived mesenchymal stem cells (MSCs)and tested the feasibility of using MSCs for β-cell replacement.Methods Bone marrow-derived MSCs were obtained from 10 DM patients (5 type 1 DM and 5 type 2 DM) and inducedto IPCs under a three-stage protocol.Representative cell surface antigen expression profiles of MSCs were analysed byflow cytometric analysis.Reverse transcription-polymerase chain reaction (RT-PCR) was performed to detect multiplegenes related to pancreatic β-cell development and function.The identity of the IPCs was illustrated by the analysis ofmorphology,ditizone staining and immunocytochemistry.Release of insulin by these cells was confirmed byimmunoradioassay.Results Flow cytometric analysis of MSCs at passage 3 showed that these cells expressed high levels of CD29(98.28%),CD44 (99.56%) and CD106 (98.34%).Typical islet-like cell clusters were observed at the end of the protocol(18 days).Ditizone staining and immunohistochemistry for insulin were both positive.These differentiated cells at stage 2(10 days) expressed nestin,pancreatic duodenal homeobox-1 (PDX-1),Neurogenin3,Pax4,insulin,glucagon,but atstage 3 (18 days) we observed the high expression of PDX-1,insulin,glucagon.Insulin was secreted by these cells inresponse to different concentrations of glucose stimulation in a regulated manner (P<0.05).Conclusions Bone marrow-derived MSCs from DM patients can differentiate into functional IPCs under certainconditions in vitro.Using diabetic patient’s own bone marrow-derived MSCs as a source of autologous IPCs for β-cellreplacement would be feasible. Bckground Stem cells, which have the ability to differentiate into insulin-producing cells (IPCs), would provide apotentially unlimited source of islet cells for transplantation and alleviate the major limitations of availability and allogeneicrejection.Therefore, the utilization of stem cells is becoming the most promising therapy for diabetes mellitus (DM). Here, we studied the differentiation capacity of the diabetic patient’s bone marrow-derived mesenchymal stem cells (MSCs) and tested the feasibility of using MSCs for β-cell replacement. Methods Bone marrow-derived MSCs were obtained from 10 DM patients (5 type 1 DM and 5 type 2 DM) and inducedto IPCs under a three-stage protocol. Representative cell surface antigen expression profiles of MSCs were analyzed by flow cytometric analysis. Reverse transcription-polymerase chain reaction (RT-PCR ) was performed to detect multiplegenes related to pancreatic β-cell development and function. The identity of the IPCs was illustrated by the analysis Of morphology, ditizone staining and immunocytochemistry. Release of insulin by these cells was confirmed by immunoradioassay. Results Flow cytometric analysis of MSCs at passage 3 showed those cells expressed high levels of CD29 (98.28%), CD44 (99.56%) and CD106 (98.34% ). Dietary islet-like cell clusters were observed at the end of the protocol (18 days). Digizone staining and immunohistochemistry for insulin were both positive. Differentiated cells at stage 2 (10 days) expressed nestin, pancreatic duodenal homeobox- 1 ( PDX-1), Neurogenin3, Pax4, insulin, glucagon, but atstage 3 (18 days) we observed the high expression of PDX-1, insulin, glucagon.Insulin was secreted by these cells in response to different concentrations of glucose stimulation in a regulated (P <0.05) .Conclusions Bone marrow-derived MSCs from differentiating into functional IPCs under certain conditions in vitro. Using MSCs as a source of autologous IPCs for β-cellre placement would be feasible.