Stem cell approaches for the treatment of type 1 diabetes mellitus

The microenvironment of silk/gelatin nanofibrous scaffold improves proliferation and differentiation of Wharton's jelly-derived mesenchymal cells into islet-like cells

The use of umbilical cord-derived mesenchymal stem cells along with three-dimensional (3D) scaffolds in pancreatic tissue engineering can be considered as a treatment for diabetes. This study aimed to investigate the differentiation of Wharton's jelly-derived mesenchymal stem cells (WJ-MSCs) into pancreatic islet-insulin producing cells (IPCs) on silk/gelatin nanofibers as a 3D scaffold. Mesenchymal markers were evaluated at the mesenchymal stem cells (MSCs) level by flow cytometry. WJ-MSCs were then cultured on 3D scaffolds and treated with a differential medium. Immunocytochemical assays showed efficient differentiation of WJ-MSCs into IPCs. Also, Real-time PCR results showed a significant increase in the expression of pancreatic genes in the 3D culture group compared to the two-dimensional (2D) culture group. Despite these cases, the secretion of insulin and C-peptide in response to different concentrations of glucose in the 3D group was significantly higher than in the 2D culture. The results of our study showed that silk/gelatin scaffold with WJ-MSCs could be a good option in the production of IPCs in regenerative medicine and pancreatic tissue engineering.

Addressing Stem Cell Therapeutic Approaches in Pathobiology of Diabetes and Its Complications

High morbidity and mortality of diabetes mellitus (DM) throughout the human population is a serious threat which needs to be addressed cautiously. Type 1 diabetes mellitus (T1DM) and type 2 diabetes mellitus (T2DM) are most prevalent forms. Disruption in insulin regulation and resistance leads to increased formation and accumulation of advanced end products (AGEs), which further enhance oxidative and nitrosative stress leading to microvascular (retinopathy, neuropathy, and nephropathy) and macrovascular complications. These complications affect the normal function of organ and tissues and may cause life-threatening disorders, if hyperglycemia persists and improperly controlled. Current and traditional treatment procedures are only focused on to regulate the insulin level and do not cure the diabetic complications. Pancreatic transplantation seemed a viable alternative; however, it is limited due to lack of donors. Cell-based therapy such as stem cells is considered as a promising therapeutic agent against DM and diabetic complications owing to their multilineage differentiation and regeneration potential. Previous studies have demonstrated the various impacts of both pluripotent and multipotent stem cells on DM and its micro- and macrovascular complications. Therefore, this review summarizes the potential of stem cells to treat DM and its related complications.

Anti-TCRβ mAb in Combination With Neurogenin3 Gene Therapy Reverses Established Overt Type 1 Diabetes in Female NOD Mice

Insulin-producing β cells in patients with type 1 diabetes (T1D) are destroyed by T lymphocytes. We investigated whether targeting the T-cell receptor (TCR) with a monoclonal antibody (mAb) abrogates T-cell response against residual and newly formed islets in overtly diabetic nonobese diabetic (NOD) mice. NOD mice with blood glucose levels of 250 to 350 mg/dL or 350 to 450 mg/dL were considered as new-onset or established overt diabetes, respectively. These diabetic NOD mice were transiently treated with an anti-TCR β chain (TCRβ) mAb, H57-597, for 5 days. Two weeks later, some NOD mice with established overt diabetes further received hepatic gene therapy using the islet-lineage determining gene Neurogenin3 (Ngn3), in combination with the islet growth factor gene betacellulin (Btc). We found that anti-TCRβ mAb (50 µg/d) reversed >80% new-onset diabetes in NOD mice for >14 weeks by reducing the number of effector T cells in the pancreas. However, anti-TCRβ mAb therapy alone reversed only ∼20% established overt diabetes in these mice. Among those overtly diabetic NOD mice whose diabetes was resistant to anti-TCRβ mAb treatment, ∼60% no longer had diabetes when they also received Ngn3-Btc hepatic gene transfer 2 weeks after initial anti-TCRβ mAb treatment. This combination of Ngn3-Btc gene therapy and anti-TCRβ mAb treatment induced the sustained formation of periportal insulin-producing cells in the liver of overtly diabetic mice. Therefore, directly targeting TCRβ with a mAb potently reverses new-onset T1D in NOD mice and protects residual and newly formed gene therapy-induced hepatic neo-islets from T-cell‒mediated destruction in mice with established overt diabetes.

Suspension Culture Alters Insulin Secretion in Induced Human Umbilical Cord Matrix-Derived Mesenchymal Cells

OBJECTIVE

Worldwide, diabetes mellitus (DM) is an ever-increasing metabolic disorder. A promising approach to the treatment of DM is the implantation of insulin producing cells (IPC) that have been derived from various stem cells. Culture conditions play a pivotal role in the quality and quantity of the differentiated cells. In this experimental study, we have applied various culture conditions to differentiate human umbilical cord matrix-derived mesenchymal cells (hUCMs) into IPCs and measured insulin production.

MATERIALS AND METHODS

In this experimental study, we exposed hUCMs cells to pancreatic medium and differentiated them into IPCs in monolayer and suspension cultures. Pancreatic medium consisted of serum-free Dulbecco's modified eagle's medium Nutrient mixture F12 (DMEM/F12) medium with 17.5 mM glucose supplemented by 10 mM nicotinamide, 10 nM exendin-4, 10 nM pentagastrin, 100 pM hepatocyte growth factor, and B-27 serum-free supplement. After differentiation, insulin content was analyzed by gene expression, immunocytochemistry (IHC) and the chemiluminesence immunoassay (CLIA).

RESULTS

Reverse transcription-polymerase chain reaction (RT-PCR) showed efficient expressions of NKX2.2, PDX1 and INSULIN genes in both groups. IHC analysis showed higher expression of insulin protein in the hanging drop group, and CLIA revealed a significant higher insulin production in hanging drops compared with the monolayer group following the glucose challenge test.

CONCLUSION

We showed by this novel, simple technique that the suspension culture played an important role in differentiation of hUCMs into IPC. This culture was more efficient than the conventional culture method commonly used in IPC differentiation and cultivation.

Comparison of therapeutic characteristics of islet cell transplantation simultaneous with pancreatic mesenchymal stem cell transplantation in rats with Type 1 diabetes mellitus

Although, pancreas islet call transplantation is a new, promising method for type 1 diabetic patients, it remains as an experimental procedure applied in selected patients. The present study aimed to investigate effect of pancreatic mesenchymal stem cell transplantation simultaneous with islet cell transplantation on islet liveliness and thus on the treatment of diabetes in type 1 diabetic rats. The study used Wistar Albino Rats and was performed in a total of four groups [control (G1), mesenchymal stem cell (G2), islet (G3) and islet + mesencymal stem cell (G4)] each including 8 rats. Blood glucose level of the rats, in which diabetes model has been created using streptozotocin, was measured after 72 h. Blood samples were obtained from the rats 30 days after transplantation and then, their livers and pancreases were kept in 10% formaldehyde and the experiment was ended. Following staining with H&E, they were morphologically evaluated under a light microscope. Change in mean blood glucose level was statistically significant in G3 and G4 versus G1 and G2 (p = 0.001, p < 0.001, p < 0.001, and p < 0.001 respectively). Histological examination revealed that mean number of islet cells in the pancreases of the rats was higher in G4; difference between the groups was statistically significant (p < 0.001). Transplantation of islet cells together with mesenchymal stem cells showed beneficial effects in terms of prolonging survival of islet grafts suggesting that transplantation of mesenchymal stem cells together with islet cells during clinical islet transplantation may be beneficial in increasing the number of noninsulin-dependent patients in Type 1 diabetes.

Long-term allogeneic islet graft survival in prevascularized subcutaneous sites without immunosuppressive treatment

Establishment of noninvasive and efficient islet transplantation site together with the avoidance of immunosuppressive drugs for islet engraftment is currently the two major tasks for islet transplantation approach to treat patients with type 1 diabetes. Here, we proposed a method to achieve long-term allogeneic islet graft function without immunosuppression after transplantation in subcutaneous sites. Two agarose rods with basic fibroblast growth factor and heparin were implanted for 1 week in dorsal subcutaneous sites in diabetic rats. After rod removal, 1500 islets were transplanted into the prevascularized pockets. Islets transplanted in prevascularized but not nontreated subcutaneous sites rapidly reverted hyperglycemia in all streptozotocin-induced diabetic rats. In contrast to transient normalization of blood glucose when allogeneic islets were transplanted into liver, allogeneic islets transplanted into this prevascularized subcutaneous site demonstrated long-term graft survival and function in all three rat strain combinations (Fisher 344 to ACI, Lewis to ACI and Fisher 344 to Wistar), evidenced by nonfasting blood glucose level, plasma insulin concentration, intraperitoneal glucose tolerance test and immunohistochemistry. These results indicated that a subcutaneous site prevascularized by this method is potentially a suitable site for successful allogeneic islet transplantation without immunosuppression.

A synthetic peptide-acrylate surface for production of insulin-producing cells from human embryonic stem cells

Human embryonic stem cells (hESCs), due to their self-renewal capacity and pluripotency, have become a potential source of transplantable β-cells for the treatment of diabetes. However, it is imperative that the derived cells fulfill the criteria for clinical treatment. In this study, we replaced common Matrigel with a synthetic peptide-acrylate surface (Synthemax) to expand undifferentiated hESCs and direct their differentiation in a defined and serum-free medium. We confirmed that the cells still expressed pluripotent markers, had the ability to differentiate into three germ layers, and maintained a normal karyotype after 10 passages of subculture. Next, we reported an efficient protocol for deriving nearly 86% definitive endoderm cells from hESCs under serum-free conditions. Moreover, we were able to obtain insulin-producing cells within 21 days following a simple three-step protocol. The results of immunocytochemical and quantitative gene expression analysis showed that the efficiency of induction was not significantly different between the Synthemax surface and the Matrigel-coated surface. Thus, we provided a totally defined condition from hESC culture to insulin-producing cell differentiation, and the derived cells could be a therapeutic resource for diabetic patients in the future.

Mechanistic basis of immunotherapies for type 1 diabetes mellitus

Type 1 diabetes (T1D) is an autoimmune disease for which there is no cure. The pancreatic beta cells are the source of insulin that keeps blood glucose normal. When susceptible individuals develop T1D, their beta cells are destroyed by autoimmune T lymphocytes and no longer produce insulin. T1D patients therefore depend on daily insulin injections for survival. Gene therapy in T1D aims at the induction of new islets to replace those that have been destroyed by autoimmunity. A major goal of T1D research is to restore functional beta cell mass while eliminating diabetogenic T cells in the hope of achieving insulin independence. Multiple therapeutic strategies for the generation of new beta cells have been under intense investigations. However, newly formed beta cells would be immediately destroyed by diabetogenic T cells. Therefore, successful islet induction therapy must be supported by potent immunotherapy that will protect the newly formed beta cells. Herein, we will summarize the current information on immunotherapies that aim at modifying T cell response to beta cells. We will first outline the immune mechanisms that underlie T1D development and progression and review the scientific background and rationale for specific modes of immunotherapy. Numerous clinical trials using antigen-specific strategies and immune-modifying drugs have been published, though most have proved too toxic or have failed to provide long-term beta cell protection. To develop an effective immunotherapy, there must be a continued effort on defining the molecular basis that underlies T cell response to pancreatic islet antigens in T1D.

Mesenchymal Stromal Cells as a Therapeutic Strategy to Support Islet Transplantation in Type 1 Diabetes Mellitus

Type 1 diabetes is an autoimmune disorder that leads to destruction of pancreatic β islet cells and is a growing global health issue. While insulin replacement remains the standard therapy for type 1 diabetes, exogenous insulin does not mimic the physiology of insulin secretion. Transplantation of pancreatic islets has the potential to cure this disease; however, there are several major limitations to widespread implementation of islet transplants. The use of mesenchymal stromal cells (MSCs) in the treatment of type 1 diabetes has been investigated as an adjunct therapy during islet graft administration to prevent initial islet loss and promote engraftment and revascularization of islets. In this review we will discuss the results of recent MSC studies in animal models of diabetes with a focus on islet transplantation and explore the potential for these findings to be extended to clinical use for the treatment of type 1 diabetes.

New hope for type 2 diabetics: targeting insulin resistance through the immune modulation of stem cells

The prevalence of type 2 diabetes (T2D) is increasing worldwide, highlighting the need for a better understanding of the pathogenesis of the disease and the development of innovative therapeutic approaches for the prevention and cure of the condition. Mounting evidence points to the involvement of immune dysfunction in insulin resistance in T2D, suggesting that immune modulation may be a useful tool in treating the disease. Recent advances in the use of adult stem cells from human umbilical cord blood and bone marrow for immune modulation hold promise for overcoming immune dysfunction in T2D without many of the complications associated with traditional immunosuppressive therapies. This review focuses on recent progress in the use of immune modulation in T2D and discusses the potential for future therapies. New insights are provided on the use of cord blood-derived multipotent stem cells (CB-SC) in T2D.

Cryopreservation of Human Stem Cells for Clinical Application: A Review

SUMMARY: Stem cells have been used in a clinical setting for many years. Haematopoietic stem cells have been used for the treatment of both haematological and non-haematological disease; while more recently mesenchymal stem cells derived from bone marrow have been the subject of both laboratory and early clinical studies. Whilst these cells show both multipotency and expansion potential, they nonetheless do not form stable cell lines in culture which is likely to limit the breadth of their application in the field of regenerative medicine. Human embryonic stem cells are pluripotent cells, capable of forming stable cell lines which retain the capacity to differentiate into cells from all three germ layers. This makes them of special significance in both regenerative medicine and toxicology. Induced pluripotent stem (iPS) cells may also provide a similar breadth of utility without some of the confounding ethical issues surrounding embryonic stem cells. An essential pre-requisite to the commercial and clinical application of stem cells are suitable cryopreservation protocols for long-term storage. Whilst effective methods for cryopreservation and storage have been developed for haematopoietic and mesenchymal stem cells, embryonic cells and iPS cells have proved more refractory. This paper reviews the current state of cryopreservation as it pertains to stem cells and in particular the embryonic and iPS cell.

Stem cells and the endocrine pancreas

BACKGROUND

Diabetes can be treated by β-cell replacement therapy but the supply of graft material from human donors is too limited to make a significant clinical impact. Substitute β-cells generated from stem cell populations offer a potential source for the large numbers of cells required.

SOURCES OF DATA

Primary peer-reviewed reports of experimental studies.

AREAS OF AGREEMENT

Embryonic stem cells and/or induced pluripotent stem (iPS) cells are currently the most promising starting populations from which to generate large numbers of β-cells. Differentiation protocols that recapitulate in vivo development generate insulin-expressing cells in vitro.

AREAS OF CONTROVERSY

Differentiation outcomes may depend on the source of the initial pluripotent cells. The insulin-expressing cells are not fully functional. In vivo maturation is inconsistent and not well understood.

AREAS TIMELY FOR DEVELOPING RESEARCH

Improvement of current protocols for complete in vitro differentiation to a functional β-cell phenotype. Systematic analysis to identify the most appropriate starting material. Improved purification methods to ensure safety of material for clinical transplantation.