The blood samples were obtained from the tail vein and measured for blood glucose levels every 3 days. of glucose-stimulated insulin secretion. Transplantation of functional IPCs into the renal subcapsular space of STZ-induced diabetic nude mice ameliorated the hyperglycemia. Immunofluorescence staining revealed that transplanted IPCs sustainably expressed insulin, c-peptide, Fgf2 and PDX-1 without apparent apoptosis can ameliorate STZ-induced diabetic hyperglycemia, which indicates that these hMSCs may be a promising approach to overcome the limitations of islet transplantation. Introduction Diabetes mellitus is a widespread devastating disease affecting millions of people alpha-Bisabolol worldwide. Although maintaining long-term glycemic control with exogenous insulin imposes an enormous physical, psychological, and financial burden on patients, it remains the only option in the face of the serious, life-threatening potential complications of diabetes. Islet transplantation is an ideal and effective treatment for type 1 diabetes; however, its application in clinical care has been largely limited by immune rejection and the shortage of donor islets . Recent progress in the field of regenerative therapies has focused on the generation of surrogate -cells from embryo-, umbilical cord blood- and various adult tissue-derived stem cells . Embryonic stem cells (ESCs) can be alpha-Bisabolol differentiated into any cell type including insulin-producing cells (IPCs) . IPCs can also be obtained by directed molecular engineering of umbilical cord blood stem cells, pancreatic stem cells, and liver stem/progenitor cells [4C6]. However, therapeutic results with the use of ESCs are not satisfactory due to a variety of challenges such as immune rejection, tumor formation, source limitations, and ethical concerns. Recent studies have shown that mesenchymal stem cells (MSCs) have the ability to differentiate into mesenchymal, endodermal and ectodermal lineages to produce osteoblasts, adipocytes, myoblasts, and endocrine cells . Transplantation of autologous MSCs would help overcome the major limitations of inadequate supply and/or allogeneic rejection. Moreover, MSCs have been shown to have an immunomodulatory effect on the suppression of the immune response in autoimmune and inflammatory diseases [8, 9]. Co-transplantation of autologous MSCs delays islet allograft rejection and generates a local immunoprivileged site for graft survival . Consequently, MSCs emerge as a much better source for the generation of surrogate -cells [11, 12]. MSCs can be isolated from many tissues including the muscle, umbilical cord blood, adipose tissue, alpha-Bisabolol and bone marrow. Among these, bone marrow-derived MSCs have the highest proliferation capacity and retain their pluripotency even after 50 passages [13, 14]. Currently, there are two methods commonly used to induce MSC differentiation into IPCs conditions. Thus, the existing induction strategy needs to be modified and improved, especially since most of the studies mentioned above are based on rodent models [18, 19]. In fact, the differentiation of human MSCs into IPCs and their function of rescuing diabetes have been rarely reported [16, 20, 21]. Therefore, the present study is designed to generate well-characterized IPCs from human bone marrow-derived MSCs (hMSCs) by using a three-stage protocol and to test their potential for controlling glucose levels in diabetic mice. This study will provide evidence to support the use of adult stem cells as a steady and renewable source of IPCs for transplantation in patients with type 1 diabetes. Materials and Methods Isolation and culture of hMSCs and induction to IPCs The protocol used in this study was approved by the Ethics Committee of the College of Basic Medical Sciences of Jilin University. Written informed consent was obtained from healthy volunteers. Human bone marrow samples were obtained from healthy volunteers by lumbar puncture in the First Hospital of Jilin University. The hMSCs were isolated and cultured as previously described . Briefly, bone mononuclear cells were isolated from human bone marrow by density gradient centrifugation in a Percoll solution (1.073 g/ml, Pharmacia, USA). The cells were cultured in low glucose (5.6 mmol/L)-Dulbeccos modified Eagles medium (L-DMEM) with 10% fetal bovine serum (FBS, Invitrogen, Carlsbad, CA), and the non-adherent cells were washed off after 48 h. For 8C12.