Human bone marrow mesenchymal stem cells differentiate into insulin-producing cells upon microenvironmental manipulation in vitro

Potentials of bone marrow cells-derived from naïve or diabetic mice in autoimmune type 1 diabetes: immunomodulatory, anti-inflammatory, anti hyperglycemic, and antioxidative

BACKGROUND

The scarcity of transplanted human islet tissue and the requirement for immunosuppressive drugs to prevent the rejection of allogeneic grafts have hindered the treatment of autoimmune type 1 diabetes mellitus (T1DM) through islet transplantation. However, there is hope in adoptively transferred bone marrow cells (BMCs) therapy, which has emerged as a propitious pathway for forthcoming medications. BMCs have the potential to significantly impact both replacement and regenerative therapies for a range of disorders, including diabetes mellitus, and have demonstrated anti-diabetic effects.

AIM

The main goal of this study is to evaluate the effectiveness of adoptively transferred bone marrow cells derived from either naïve mice (nBMCs) or diabetic mice (dBMCs) in treating a T1DM mice model.

METHODS

Male Swiss albino mice were starved for 16 h and then injected with streptozotocin (STZ) at a dose of 40 mg/kg body weight for 5 consecutive days to induce T1DM. After 14 days, the diabetic mice were distributed into four groups. The first group served as a diabetic control treated with sodium citrate buffer, while the other three groups were treated for two weeks, respectively, with insulin (subcutaneously at a dose of 8 U/kg/day), nBMCs (intravenously at a dose of 1 × 106 cells/mouse/once), and dBMCs (intravenously at a dose of 1 × 106 cells/mouse/once).

RESULTS

It is worth noting that administering adoptively transferred nBMCs or adoptively transferred dBMCs to STZ-induced T1DM mice resulted in a significant amelioration in glycemic condition, accompanied by a considerable reduction in the level of blood glucose and glycosylated hemoglobin % (HbA1C %), ultimately restoring serum insulin levels to their initial state in control mice. Administering nBMCs or dBMCs to STZ-induced T1DM mice led to a remarkable decrease in levels of inflammatory cytokine markers in the serum, including interferon-γ (INF-γ), tumor necrosis factor- α (TNF-α), tumor growth factor-β (TGF-β), interleukin-1 β (L-1β), interlekin-4 (IL-4), interleukin-6 (IL-6), and interleukin-10 (IL-10). Additionally, STZ-induced T1DM mice, when treated with nBMCs or dBMCs, experienced a notable rise in total immunoglobulin (Ig) level. Furthermore, there was a significant reduction in the levels of islet cell autoantibodies (ICA) and insulin autoantibodies (IAA). Furthermore, the serum of STZ-induced T1DM mice showed a significant increase in Zinc transporter 8 antigen protein (ZnT8), islet antigen 2 protein (IA-2), and glutamic acid decarboxylase antigen protein (GAD) levels. Interestingly, the administration of nBMCs or dBMCs resulted in a heightened expression of IA-2 protein in STZ-induced T1DM mice treated with nBMCs or dBMCs. Furthermore, the level of malondialdehyde (MDA) was increased, while the levels of catalase (CAT) and superoxide dismutase (SOD) were decreased in non-treated STZ-induced T1DM mice. However, when nBMCs or dBMCs were administered to STZ-induced T1DM mice, it had a significant impact on reducing oxidative stress. This was accomplished by reducing the levels of MDA in the serum and enhancing the activities of enzymatic antioxidants like CAT and SOD. STZ-induced T1DM mice displayed a significant elevation in the levels of liver enzymes ALT and AST, as well as heightened levels of creatinine and urea. Considering the crucial roles of the liver and kidney in metabolism and excretion, this research further examined the effects of administering nBMCs or dBMCs to STZ-induced T1DM mice. Notably, the administration of these cells alleviated the observed effects.

CONCLUSION

The present study suggests that utilizing adoptively transferred nBMCs or adoptively transferred dBMCs in the treatment of T1DM led to noteworthy decreases in blood glucose levels, possibly attributed to their capacity to enhance insulin secretion and improve the performance of pancreatic islets. Additionally, BMCs may exert their beneficial effects on the pancreatic islets of diabetic mice through their immunomodulatory, antioxidant, anti-inflammatory, and anti-oxidative stress properties.

A hybrid construct of decellularized matrix and fibrin for differentiating adipose stem cells into insulin-producing cells, an optimized in vitro assessment

The generation of insulin-producing cells (IPCs) is an attractive approach for replacing damaged β cells in diabetic patients. In the present work, we introduced a hybrid platform of decellularized amniotic membrane (dAM) and fibrin encapsulation for differentiating adipose tissue-derived stem cells (ASCs) into IPCs. ASCs were isolated from healthy donors and characterized. Human AM was decellularized, and its morphology, DNA, collagen, glycosaminoglycan (GAG) contents, and biocompatibility were evaluated. ASCs were subjected to four IPC differentiation methods, and the most efficient method was selected for the experiment. ASCs were seeded onto dAM, alone or encapsulated in fibrin gel with various thrombin concentrations, and differentiated into IPCs according to a method applying serum-free media containing 2-mercaptoethanol, nicotinamide, and exendin-4. PDX-1, GLUT-2 and insulin expression were evaluated in differentiated cells using real-time PCR. Structural integrity and collagen and GAG contents of AM were preserved after decellularization, while DNA content was minimized. Cultivating ASCs on dAM augmented their attachment, proliferation, and viability and enhanced the expression of PDX-1, GLUT-2, and insulin in differentiated cells. Encapsulating ASCs in fibrin gel containing 2 mg/ml fibrinogen and 10 units/ml thrombin increased their differentiation into IPCs. dAM and fibrin gel synergistically enhanced the differentiation of ASCs into IPCs, which could be considered an appropriate strategy for replacing damaged β cells.

Current Landscape of Various Techniques and Methods of Gene Therapy through CRISPR Cas9 along with its Pharmacological and Interventional Therapies in the Treatment of Type 2 Diabetes Mellitus

BACKGROUND

Type 2 diabetes mellitus (T2DM) is frequently referred to as a "lifestyle illness". In 2000, India (31.7 million) had the greatest global prevalence of diabetes mellitus, followed by China (20.8 million), the United States (17.7 million), and other countries. In recent years, the treatment of gene therapy (T2DM) has attracted intensive interest.

OBJECTIVE

We aimed to critically review the literature on the various techniques and methods, which may be a possible novel approach through the gene therapy CRISPR Cas9 and some other gene editing techniques for T2DM. Interventional and pharmacological approaches for the treatment of T2DM were also included to identify novel therapies for its treatment.

METHOD

An extensive literature survey was done on databases like PubMed, Elsevier, Science Direct and Springer.

CONCLUSION

It can be concluded from the study that recent advancements in gene-editing technologies, such as CRISPR Cas9, have opened new avenues for the development of novel therapeutic approaches for T2DM. CRISPR Cas9 is a powerful tool that enables precise and targeted modifications of the genome.

Stem cells therapy for diabetes: from past to future

Diabetes mellitus is a chronic disease of carbohydrate metabolism characterized by uncontrolled hyperglycemia due to the body's impaired ability to produce or respond to insulin. Oral or injectable exogenous insulin and its analogs cannot mimic endogenous insulin secreted by healthy individuals, and pancreatic and islet transplants face a severe shortage of sources and transplant complications, all of which limit the widespread use of traditional strategies in diabetes treatment. We are now in the era of stem cells and their potential in ameliorating human disease. At the same time, the rapid development of gene editing and cell-encapsulation technologies has added to the wings of stem cell therapy. However, there are still many unanswered questions before stem cell therapy can be applied clinically to patients with diabetes. In this review, we discuss the progress of strategies to obtain insulin-producing cells from different types of stem cells, the application of gene editing in stem cell therapy for diabetes, as well as summarize the current advanced cell encapsulation technologies in diabetes therapy and look forward to the future development of stem cell therapy in diabetes.

A Supportive Role of Mesenchymal Stem Cells on Insulin-Producing Langerhans Islets with a Specific Emphasis on The Secretome

Type 1 Diabetes (T1D) is a chronic autoimmune disease characterized by a gradual destruction of insulin-producing β-cells in the endocrine pancreas due to innate and specific immune responses, leading to impaired glucose homeostasis. T1D patients usually require regular insulin injections after meals to maintain normal serum glucose levels. In severe cases, pancreas or Langerhans islet transplantation can assist in reaching a sufficient β-mass to normalize glucose homeostasis. The latter procedure is limited because of low donor availability, high islet loss, and immune rejection. There is still a need to develop new technologies to improve islet survival and implantation and to keep the islets functional. Mesenchymal stem cells (MSCs) are multipotent non-hematopoietic progenitor cells with high plasticity that can support human pancreatic islet function both in vitro and in vivo and islet co-transplantation with MSCs is more effective than islet transplantation alone in attenuating diabetes progression. The beneficial effect of MSCs on islet function is due to a combined effect on angiogenesis, suppression of immune responses, and secretion of growth factors essential for islet survival and function. In this review, various aspects of MSCs related to islet function and diabetes are described.

Exocrine pancreas regeneration modifies original pancreas to alleviate diabetes in mouse models

Diabetes is a major public health issue because of its widely epidemic nature and lack of cure. Here, we show that pancreas-derived mesenchymal stem cells (PMSCs) are capable of regenerating exocrine pancreas when implanted into the kidney capsule of mice with streptozotocin (STZ)-induced diabetes. Mechanistically, we found that the regenerated exocrine pancreas elevated interleukin-6 (IL-6) in PMSC implants, which transiently activated tumor necrosis factor-α (TNF-α) and interferon-γ (IFN-γ) to inhibit IL-17, thereby rescuing damaged exocrine pancreas and islet β cells. In addition, we used knockout mouse models to show that global lack of IL-6, TNF-α, or IFN-γ resulted in increased severity of STZ-induced diabetes and resistance to PMSC implantation therapy, confirming the roles of these factors in safeguarding pancreatic β cells. Furthermore, removal of the kidney capsule PMSC implants at 28 days after implantation did not affect the PMSC-initiated therapeutic effect on diabetic mice. This study reveals a previously unknown role of exocrine pancreas regeneration in safeguarding β cells and demonstrates a "soil-rescues-seed" strategy for type 1 diabetes therapy.

Feline Adipose Derived Multipotent Stromal Cell Transdifferentiation Into Functional Insulin Producing Cell Clusters

Diabetes mellitus (DM) is one of the most prevalent feline endocrinopathies, affecting up to 1% of pet cats. De novo generation of functional insulin producing cell (IPC) clusters via transdifferentiation of feline adipose-derived multipotent stromal cells (ASCs) may not only provide a viable, functional cell therapy for feline DM, but may also serve as a platform for developing a comparable human treatment given feline and human DM similarities. Cells were induced to form IPCs with a novel, three-stage culture process with stromal or differentiation medium under static and dynamic conditions. Clusters were evaluated for intracellular zinc, viability, intracellular insulin, glucagon, and somatostatin, ultrastructure, glucose stimulated insulin secretion in the presence or absence of theophylline, and protein and gene expression. Isolated cells were multipotent, and cell clusters cultured in both media had robust cell viability. Those cultured in differentiation medium contained zinc and mono- or polyhormonal α-, β-, and δ-like cells based on immunohistochemical labeling and Mallory-Heidenhan Azan-Gomori’s staining. Ultrastructurally, cell clusters cultured in differentiation medium contained insulin granules within vesicles, and clusters had a concentration-dependent insulin response to glucose in the presence and absence of theophylline which increased both insulin secretion and intracellular content. Expression of NK6.1, Pax6, Isl1, Glut2, RAB3A, glucagon, insulin, and somatostatin increased with differentiation stage for both sexes, and expression of nestin at stages 1 and 2 and Neurod1 at stage 2 was higher in cells from female donors. The cluster insulin secretion responses and endocrine and oncogene gene expression profiles were inconsistent with insulinoma characteristics. A total of 180 proteins were upregulated in differentiated clusters, and the majority were associated with biological regulation, metabolic processes, or stimulus response. Dynamic culture of IPC clusters resulted in clusters composed of cells primarily expressing insulin that released higher insulin with glucose stimulation than those in static culture. Collectively, the results of this study support generation of functional IPC clusters using feline ASCs isolated from tissues removed during routine sterilization. Further, cluster functionality is enhanced with dynamic, motion-driven shear stress. This work establishes a foundation for development of strategies for IPC therapy for short or long-term diabetes treatment and may represent an option to study prevention and treatment of diabetes across species.

Emerging Treatment Strategies for Diabetes Mellitus and Associated Complications: An Update

The occurrence of diabetes mellitus (DM) is increasing rapidly at an accelerating rate worldwide. The status of diabetes has changed over the last three generations; whereas before it was deemed a minor disease of older people but currently it is now one of the leading causes of morbidity and mortality among middle-aged and young people. High blood glucose-mediated functional loss, insulin sensitivity, and insulin deficiency lead to chronic disorders such as Type 1 and Type 2 DM. Traditional treatments of DM, such as insulin sensitization and insulin secretion cause undesirable side effects, leading to patient incompliance and lack of treatment. Nanotechnology in diabetes studies has encouraged the development of new modalities for measuring glucose and supplying insulin that hold the potential to improve the quality of life of diabetics. Other therapies, such as β-cells regeneration and gene therapy, in addition to insulin and oral hypoglycemic drugs, are currently used to control diabetes. The present review highlights the nanocarrier-based drug delivery systems and emerging treatment strategies of DM.

Comparison of the Characteristics of Breast Milk-derived Stem Cells with the Stem Cells Derived from the Other Sources: A Comparative Review

Breast milk (BrM) not only supplies nutrition, but it also contains a diverse population of cells. It has been estimated that up to 6% of the cells in human milk possess the characteristics of mesenchymal stem cells (MSC). Available data also indicate that these cells are multipotent and capable of self-renewal and differentiation with other cells. In this review, we have compared different characteristics, such as CD markers, differentiation capacity, and morphology of stem cells, derived from human breast milk (hBr-MSC) with human bone marrow (hBMSC), Wharton's jelly (WJMSC), and human adipose tissue (hADMSC). Through the literature review, it was revealed that human breast milk-derived stem cells specifically express a group of cell surface markers, including CD14, CD31, CD45, and CD86. Importantly, a group of markers, CD13, CD29, CD44, CD105, CD106, CD146, and CD166, were identified, which were common in the four sources of stem cells. WJMSC, hBMSC, hADMSC, and hBr-MSC are potently able to differentiate into the mesoderm, ectoderm, and endoderm cell lineages. The ability of hBr-MSCs todifferentiate into the neural stem cells, neurons, adipocyte, hepatocyte, chondrocyte, osteocyte, and cardiomyocytes has made these cells a promising source of stem cells in regenerative medicine, while isolation of stem cells from the commonly used sources, such as bone marrow, requires invasive procedures. Although autologous breast milk-derived stem cells are an accessible source for women who are in the lactation period, breast milk can be considered as a source of stem cells with high differentiation potential without any ethical concern.

Human umbilical cord mesenchymal stem cells in type 2 diabetes mellitus: the emerging therapeutic approach

The umbilical cord has been proved to be an easy-access, reliable, and useful source of mesenchymal stem cells (MSC) for clinical applications due to its primitive, immunomodulatory, non-immunogenic, secretory and paracrine, migratory, proliferative, and multipotent properties. This set of characteristics has recently attracted great research interest in the fields of nanotechnology and regenerative medicine and cellular therapy. Accumulating evidence supports a pronounced therapeutic potential of MSC in many different pathologies, from hematology to immunology, wound-healing, tissue regeneration, and oncology. Diabetes mellitus, branded the epidemic of the century, is considered a chronic metabolic disorder, representing a major burden for health system sustainability and an important public health challenge to modern societies. The available treatments for type 2 diabetes mellitus (T2DM) still rely mainly on combinations of oral antidiabetic agents with lifestyle and nutritional adjustments. Despite the continuous development of novel and better hypoglycemic drugs, their efficacy is limited in the installment and progression of silent T2DM complications. T2DM comorbidities and mortality rates still make it a serious, common, costly, and long-term manageable disease. Recently, experimental models, preclinical observations, and clinical studies have provided some insights and preliminary promising results using umbilical cord MSCs to treat and manage diabetes. This review focuses on the latest research and applications of human-derived umbilical cord MSC in the treatment and management of T2DM, exploring and systematizing the key effects of both umbilical cord MSC and its factor-rich secretome accordingly with the major complications associated to T2DM.

Diagnosis and treatment of type 1 diabetes at the dawn of the personalized medicine era

Type 1 diabetes affects millions of people globally and requires careful management to avoid serious long-term complications, including heart and kidney disease, stroke, and loss of sight. The type 1 diabetes patient cohort is highly heterogeneous, with individuals presenting with disease at different stages and severities, arising from distinct etiologies, and overlaying varied genetic backgrounds. At present, the “one-size-fits-all” treatment for type 1 diabetes is exogenic insulin substitution therapy, but this approach fails to achieve optimal blood glucose control in many individuals. With advances in our understanding of early-stage diabetes development, diabetes stratification, and the role of genetics, type 1 diabetes is a promising candidate for a personalized medicine approach, which aims to apply “the right therapy at the right time, to the right patient”. In the case of type 1 diabetes, great efforts are now being focused on risk stratification for diabetes development to enable pre-clinical detection, and the application of treatments such as gene therapy, to prevent pancreatic destruction in a sub-set of patients. Alongside this, breakthroughs in stem cell therapies hold great promise for the regeneration of pancreatic tissues in some individuals. Here we review the recent initiatives in the field of personalized medicine for type 1 diabetes, including the latest discoveries in stem cell and gene therapy for the disease, and current obstacles that must be overcome before the dream of personalized medicine for all type 1 diabetes patients can be realized.

The modulation of mature dendritic cells from patients with type 1 diabetes using human periodontal ligament stem cells. An in-vitro study

Objective

This in vitro study aimed to investigate whether human periodontal ligament stem cells isolated from impacted third molars can modify the maturation and phenotype of monocyte-derived dendritic cells pulsed with GAD-65 obtained from patients with type 1 diabetes.

Background

Human periodontal ligament stem cells (PDLSCs) have been found to display cell surface marker characteristics similar to bone marrow stromal stem cells (BMSSCs). The immunosuppressive effects on dendritic cells (DCs), T and B cells as well as their low immunogenicity allow the use of PDLSCs in stem cell therapies for autoimmune diseases including type 1 diabetes (T1D). Studies on the immunomodulatory potential of PDLSCs in the context type 1 diabetes are lacking but are therefore worth pursuing.

Methods

CD14 + monocytes isolated from peripheral blood mononuclear cells (PBMNCs) of type 1 diabetic patients were differentiated into immature Dendritic Cells (iDCs) and then maturation was induced to generate Mature Dendritic Cells (mDCs). The mDCs were pulsed with human recombinant GAD-65 and then co-cultured with PDLSCs that were isolated from impacted third molars and characterized. The changes in the levels of differentiation and maturation surface markers on the dendritic cells were analyzed by flow cytometry at the immature state, mature state and after the co-culture experiment. The levels of the secreted cytokines; IL-6, IL-10, and TGF-β were measured by ELISA in cell-free culture supernatant.

Results

PDLSCs exerted an immunosuppressive effect on fully mature dendritic cells from patients with type 1 diabetes. This immunoregulatory property of was apparent by the reduction of all maturation markers including CD80, CD83, CD86, CD40, CD1a, CD209 and HLA-DR. Moreover, there was a detection of high levels of anti-inflammatory cytokines in the co-culture supernatant media including a significant increase in the concentration of IL-6 and TGF-β.

Conclusions

The current in vitro study provides strong evidence that PDLSCs seem to be a very promising source for overcoming the autoimmune destruction seen in T1D as they exerted an immunosuppressive effect on monocyte derived mDCs from patients with T1D. Additional studies should be conducted to further reveal the immunomodulatory and suppressive properties of PDLSCs and their potential use in immunotherapy for this disease.

Alginate/Pluronic F127-based encapsulation supports viability and functionality of human dental pulp stem cell-derived insulin-producing cells

BACKGROUND

Current approach for diabetes treatment remained several adverse events varied from gastrointestinal to life-threatening symptoms. Regenerative therapy regarding Edmonton protocol has been facing serious limitations involving protocol efficiency and safety. This led to the study for alternative insulin-producing cell (IPC) resource and transplantation platform. In this study, evaluation of encapsulated human dental pulp-derived stem cell (hDPSC)-derived IPCs by alginate (ALG) and pluronic F127-coated alginate (ALGPA) was performed.

RESULTS

The results showed that ALG and ALGPA preserved hDPSC viability and allowed glucose and insulin diffusion in and out. ALG and ALGPA-encapsulated hDPSC-derived IPCs maintained viability for at least 336 h and sustained pancreatic endoderm marker (NGN3), pancreatic islet markers (NKX6.1, MAF-A, ISL-1, GLUT-2 and INSULIN), and intracellular pro-insulin and insulin expressions for at least 14 days. Functional analysis revealed a glucose-responsive C-peptide secretion of ALG- and ALGPA-encapsulated hDPSC-derived IPCs at 14 days post-encapsulation.

CONCLUSION

ALG and ALGPA encapsulations efficiently preserved the viability and functionality of hDPSC-derived IPCs in vitro and could be the potential transplantation platform for further clinical application.

Direct lineage tracing reveals Activin-a potential for improved pancreatic homing of bone marrow mesenchymal stem cells and efficient ß-cell regeneration in vivo

BACKGROUND

Despite the potential, bone marrow-derived mesenchymal stem cells (BMSCs) show limitations for beta (ß)-cell replacement therapy due to inefficient methods to deliver BMSCs into pancreatic lineage. In this study, we report TGF-ß family member protein, Activin-a potential to stimulate efficient pancreatic migration, enhanced homing and accelerated ß-cell differentiation.

METHODS

Lineage tracing of permanent green fluorescent protein (GFP)- tagged donor murine BMSCs transplanted either alone or in combination with Activin-a in diabetic mice displayed potential ß-cell regeneration and reversed diabetes.

RESULTS

Pancreatic histology of Activin-a treated recipient mice reflected high GFP⁺BMSC infiltration into damaged pancreas with normalized fasting blood glucose and elevated serum insulin. Whole pancreas FACS profiling of GFP⁺ cells displayed significant homing of GFP⁺BMSC with Activin-a treatment (6%) compared to BMSCs alone transplanted controls (0.5%). Within islets, approximately 5% GFP+ cells attain ß-cell signature (GFP⁺ Ins⁺) with Activin-a treatment versus controls. Further, double immunostaining for mesenchymal stem cell markers CD44⁺/GFP⁺ in infiltrated GFP⁺BMSC deciphers substantial endocrine reprogramming and ß-cell differentiation (6.4% Ins⁺/GFP⁺) within 15 days.

CONCLUSION

Our investigation thus presents a novel pharmacological approach for stimulating direct migration and homing of therapeutic BMSCs that re-validates BMSC potential for autologous stem cell transplantation therapy in diabetes.

Control of Hyperglycemia Using Differentiated and Undifferentiated Mesenchymal Stem Cells in Rats with Type 1 Diabetes

Due to their ability in self-renewing and differentiation into a wide variety of tissues, mesenchymal stem cells (MSCs) exhibit outstanding potential for regenerative medicine. This study was aimed at investigating different aspects of MSC therapy in controlling hyperglycemia in streptozotocin-induced diabetes rats. Using an islet cell differentiation protocol, bone marrow (BM) MSCs were differentiated into insulin-producing cells (IPCs). The differentiation process was evaluated by immunocytochemistry, reverse transcriptase PCR, and dithizone staining. Diabetic animals in 4 diabetic individual groups received normal saline, BM-MSCs, coadministration of BM-MSCs with supernatant, and IPCs. Blood glucose and insulin levels were monitored during the experiment. Immunohistochemical analysis of the pancreas was performed at the end of the experiment. Administration of BM-MSCs could not reverse glucose and insulin levels in experimental animals as efficiently as cotransplantation of BM-MSCs with supernatant. The effect of coadministration of BM-MSCs with supernatant and transplantation of IPCs on controlling hyperglycemia is comparable. Immunohistochemical analysis showed that number and size of islets per section were significantly increased in groups receiving IPCs and BM-MSC-supernatant compared to the MSC group of animals. In conclusion, coadministration of BM-MSCs with supernatant could be used as efficiently as IPC transplantation in controlling hyperglycemia in diabetic rats.

Administration of Human Non-Diabetic Mesenchymal Stromal Cells to a Murine Model of Diabetic Fracture Repair: A Pilot Study

Individuals living with type 1 diabetes mellitus may experience an increased risk of long bone fracture. These fractures are often slow to heal, resulting in delayed reunion or non-union. It is reasonable to theorize that the underlying cause of these diabetes-associated osteopathies is faulty repair dynamics as a result of compromised bone marrow progenitor cell function. Here it was hypothesized that the administration of non-diabetic, human adult bone marrow-derived mesenchymal stromal cells (MSCs) would enhance diabetic fracture healing. Human MSCs were locally introduced to femur fractures in streptozotocin-induced diabetic mice, and the quality of de novo bone was assessed eight weeks later. Biodistribution analysis demonstrated that the cells remained in situ for three days following administration. Bone bridging was evident in all animals. However, a large reparative callus was retained, indicating non-union. µCT analysis elucidated comparable callus dimensions, bone mineral density, bone volume/total volume, and volume of mature bone in all groups that received cells as compared to the saline-treated controls. Four-point bending evaluation of flexural strength, flexural modulus, and total energy to re-fracture did not indicate a statistically significant change as a result of cellular administration. An ex vivo lymphocytic proliferation recall assay indicated that the xenogeneic administration of human cells did not result in an immune response by the murine recipient. Due to this dataset, the administration of non-diabetic bone marrow-derived MSCs did not support fracture healing in this pilot study.

Transplantation of human dental pulp stem cells in streptozotocin-induced diabetic rats

Type 1 diabetes mellitus (T1DM) is a chronic metabolic disease caused by the destruction of pancreatic β-cells. Human dental pulp stem cells represent a promising source for cell-based therapies, owing to their easy, minimally invasive surgical access, and high proliferative capacity. It was reported that human dental pulp stem cells can differentiate into a pancreatic cell lineage in vitro; however, few studies have investigated their effects on diabetes. Our study aimed to investigate the therapeutic potential of intravenous and intrapancreatic transplantation of human dental pulp stem cells in a rat model of streptozotocin-induced type 1 diabetes. Forty Sprague Dawley male rats were randomly categorized into four groups: control, diabetic (STZ), intravenous treatment group (IV), and intrapancreatic treatment group (IP). Human dental pulp stem cells (1 × 10⁶ cells) or vehicle were injected into the pancreas or tail vein 7 days after streptozotocin injection. Fasting blood glucose levels were monitored weekly. Glucose tolerance test, rat and human serum insulin and C-peptide, pancreas histology, and caspase-3, vascular endothelial growth factor, and Ki67 expression in pancreatic tissues were assessed 28 days post-transplantation. We found that both IV and IP transplantation of human dental pulp stem cells reduced blood glucose and increased levels of rat and human serum insulin and C-peptide. The cells engrafted and survived in the streptozotocin-injured pancreas. Islet-like clusters and scattered human dental pulp stem cells expressing insulin were observed in the pancreas of diabetic rats with some difference in the distribution pattern between the two injection routes. RT-PCR analyses revealed the expression of the human-specific pancreatic β-cell genes neurogenin 3 (NGN3), paired box 4 (PAX4), glucose transporter 2 (GLUT2), and insulin in the pancreatic tissues of both the IP and IV groups. In addition, the transplanted cells downregulated the expression of caspase-3 and upregulated the expression of vascular endothelial growth factor and Ki67, suggesting that the injected cells exerted pro-angiogenetic and antiapoptotic effects, and promoted endogenous β-cell replication. Our study is the first to show that human dental pulp stem cells can migrate and survive within streptozotocin-injured pancreas, and induce antidiabetic effects through the differentiation and replacement of lost β-cells and paracrine-mediated pancreatic regeneration. Thus, human dental pulp stem cells may have therapeutic potential to treat patients with long term T1DM.

Identifying the Therapeutic Significance of Mesenchymal Stem Cells

The pleiotropic behavior of mesenchymal stem cells (MSCs) has gained global attention due to their immense potential for immunosuppression and their therapeutic role in immune disorders. MSCs migrate towards inflamed microenvironments, produce anti-inflammatory cytokines and conceal themselves from the innate immune system. These signatures are the reason for the uprising in the sciences of cellular therapy in the last decades. Irrespective of their therapeutic role in immune disorders, some factors limit beneficial effects such as inconsistency of cell characteristics, erratic protocols, deviating dosages, and diverse transfusion patterns. Conclusive protocols for cell culture, differentiation, expansion, and cryopreservation of MSCs are of the utmost importance for a better understanding of MSCs in therapeutic applications. In this review, we address the immunomodulatory properties and immunosuppressive actions of MSCs. Also, we sum up the results of the enhancement, utilization, and therapeutic responses of MSCs in treating inflammatory diseases, metabolic disorders and diabetes.

Therapeutic Potential of “Exosomes Derived Multiple Allogeneic Proteins Paracrine Signaling: Exosomes d-MAPPS” is Based on the Effects of Exosomes, Immunosuppressive and Trophic Factors

Due to their differentiation capacity and potent immunosuppressive and pro-angiogenic properties, mesenchymal stem cells (MSCs) have been considered as new therapeutic agents in regenerative medicine. Since most of MSC-mediated beneficent effects are a consequence of their paracrine action, we designed MSC-based product “Exosomes Derived Multiple Allogeneic Proteins Paracrine Signaling (Exosomes d-MAPPS), which activity is based on MSCs-derived growth factors and immunomodulatory cytokines capable to attenuate inflammation and to promote regeneration of injured tissues. Interleukin 1 receptor antagonist (IL-1Ra) and IL-27 were found in high concentrations in Exosomes d-MAPPS samples indicating strong anti-inflammatory and immunosuppressive potential of Exosomes d-MAPPS. Additionally, high concentrations of vascular endothelial growth factor receptor (VEGFR1) and chemokines (CXCL16, CCL21, CXCL14) were noticed at Exosomes d-MAPPS samples suggesting their potential to promote generation of new blood vessels and migration of CXCR6, CCR7 and CXCR4 expressing cells. Since all proteins which were found in high concentration in Exosomes d-MAPPS samples (IL-1Ra, CXCL16, CXCL14, CCL21, IL-27 and VEGFR1) are involved in modulation of lung, eye, and synovial inflammation, Exosomes d-MAPPS samples were prepared as inhalation and ophthalmic solutions in addition to injection formulations; their application in several patients suffering from chronic obstructive pulmonary disease, osteoarthritis, and dry eye syndrome resulted with significant improvement of biochemical and functional parameters. In conclusion, Exosomes d-MAPPS, due to the presence of important anti-inflammatory, immunomodulatory, and pro-angiogenic factors, represents potentially new therapeutic agent in regenerative medicine that should be further tested in large clinical studies.

An overview on small molecule-induced differentiation of mesenchymal stem cells into beta cells for diabetic therapy

The field of regenerative medicine provides enormous opportunities for generating beta cells from different stem cell sources for cellular therapy. Even though insulin-secreting cells can be generated from a variety of stem cell types like pluripotent stem cells and embryonic stem cells, the ideal functional cells should be generated from patients' own cells and expanded to considerable levels by non-integrative culture techniques. In terms of the ease of isolation, plasticity, and clinical translation to generate autologous cells, mesenchymal stem cell stands superior. Furthermore, small molecules offer a great advantage in terms of generating functional beta cells from stem cells. Research suggests that most of the mesenchymal stem cell-based protocols to generate pancreatic beta cells have small molecules in their cocktail. However, most of the protocols generate cells that mimic the characteristics of human beta cells, thereby generating "beta cell-like cells" as opposed to mature beta cells. Diabetic therapy becomes feasible only when there are robust, functional, and safe cells for replacing the damaged or lost beta cells. In this review, we discuss the current protocols used to generate beta cells from mesenchymal cells, with emphasis on small molecule-mediated conversion into insulin-producing beta cell-like cells. Our data and the data presented from the references within this review would suggest that although mesenchymal stem cells are an attractive cell type for cell therapy they are not readily converted into functional mature beta cells.

Functional beta-cells derived from umbilical cord blood mesenchymal stem cells for curing rats with streptozotocin-induced diabetes mellitus

INTRODUCTION

This study aimed to investigate the therapeutic response to injected human umbilical cord blood mesenchymal stem cells (UCBMSCs) among albino rats with streptozotocin (STZ)-induced diabetes mellitus.

METHODS

Control group (GI; n = 25) rats were fed with standard rat diet. Rats with STZ-induced diabetes mellitus without (GII; n = 25) and with (GIII; n = 25) differentiated human UCBMSCs implantation were the test groups. Rats were sacrificed in Week 11 following implantation. Liver biopsies were sectioned and stained in order to highlight both the presence and function of impregnated cells in the liver tissue.

RESULTS

Haematoxylin and eosin-stained sections in GI and GII rats showed normal liver architecture while GIII rats showed presence of cell clusters inside the liver tissue and around the central veins. Cell clusters with blue cytoplasm were present in sections in GIII rats but absent in GI and GII rats, indicating the presence of injected differentiated human UCBMSCs. The anti-human insulin immunostaining of GIII rats showed clusters of cells within the liver parenchyma and around central veins, indicating that these cells were active and secreting insulin.

CONCLUSION

UCBMSCs are proficient in differentiating into insulin-producing cells in vivo under specific conditions and, when transplanted into the liver of albino rats with STZ-induced diabetes mellitus, were able to secrete insulin and partially control the status of diabetes mellitus in rats.

Ex Vivo Expansion of Murine MSC Impairs Transcription Factor-Induced Differentiation into Pancreatic β-Cells

Combinatorial gene and cell therapy as a means of generating surrogate β-cells has been investigated for the treatment of type 1 diabetes (T1D) for a number of years with varying success. One of the limitations of current cell therapies for T1D is the inability to generate sufficient quantities of functional transplantable insulin-producing cells. Due to their impressive immunomodulatory properties, in addition to their ease of expansion and genetic modification ex vivo, mesenchymal stem cells (MSCs) are an attractive alternative source of adult stem cells for regenerative medicine. To overcome the aforementioned limitation of current therapies, we assessed the utility of ex vivo expanded bone marrow-derived murine MSCs for their persistence in immune-competent and immune-deficient animal models and their ability to differentiate into surrogate β-cells. CD45⁻/Ly6⁺ murine MSCs were isolated from the bone marrow of nonobese diabetic (NOD) mice and nucleofected to express the bioluminescent protein, Firefly luciferase (Luc2). The persistence of a subcutaneous (s.c.) transplant of Luc2-expressing MSCs was assessed in immune-competent (NOD) (n = 4) and immune-deficient (NOD/Scid) (n = 4) animal models of diabetes. Luc2-expressing MSCs persisted for 2 and 12 weeks, respectively, in NOD and NOD/Scid mice. Ex vivo expanded MSCs were transduced with the HMD lentiviral vector (MOI = 10) to express furin-cleavable human insulin (INS-FUR) and murine NeuroD1 and Pdx1. This was followed by the characterization of pancreatic transdifferentiation via reverse transcriptase polymerase chain reaction (RT-PCR) and static and glucose-stimulated insulin secretion (GSIS). INS-FUR-expressing MSCs were assessed for their ability to reverse diabetes after transplantation into streptozotocin- (STZ-) diabetic NOD/Scid mice (n = 5). Transduced MSCs did not undergo pancreatic transdifferentiation, as determined by RT-PCR analyses, lacked glucose responsiveness, and upon transplantation did not reverse diabetes. The data suggest that ex vivo expanded MSCs lose their multipotent differentiation potential and may be more useful as gene therapy targets prior to expansion.

Stem cells in the treatment of diabetes mellitus - Focus on mesenchymal stem cells

Diabetes mellitus type 1 and type 2 have become a global epidemic with dramatically increasing incidences. Poorly controlled diabetes is associated with severe life-threatening complications. Beside traditional treatment with insulin and oral anti-diabetic drugs, clinicians try to improve patient's care by cell therapies using embryonic stem cells (ESC), induced pluripotent stem cells (iPSC) and adult mesenchymal stem cells (MSC). ESC display a virtually unlimited plasticity, including the differentiation into insulin producing β-cells, but they raise ethical concerns and bear, like iPSC, the risk of tumours. IPSC may further inherit somatic mutations and remaining somatic transcriptional memory upon incomplete re-programming, but allow the generation of patient/disease-specific cell lines. MSC avoid such issues but have not been successfully differentiated into β-cells. Instead, MSC and their pericyte phenotypes outside the bone marrow have been recognized to secrete numerous immunomodulatory and tissue regenerative factors. On this account, the term 'medicinal signaling cells' has been proposed to define the new conception of a 'drug store' for injured tissues and to stay with the MSC nomenclature. This review presents the biological background and the resulting clinical potential and limitations of ESC, iPSC and MSC, and summarizes the current status quo of cell therapeutic concepts and trials.

Type 1 and 2 diabetes mellitus: A review on current treatment approach and gene therapy as potential intervention

Type 1 and type 2 diabetes mellitus is a serious and lifelong condition commonly characterised by abnormally elevated blood glucose levels due to a failure in insulin production or a decrease in insulin sensitivity and function. Over the years, prevalence of diabetes has increased globally and it is classified as one of the leading cause of high mortality and morbidity rate. Furthermore, diabetes confers a huge economic burden due to its management costs as well as its complications are skyrocketing. The conventional medications in diabetes treatment focusing on insulin secretion and insulin sensitisation cause unwanted side effects to patients and lead to incompliance as well as treatment failure. Besides insulin and oral hypoglycaemic agents, other treatments such as gene therapy and induced β-cells regeneration have not been widely introduced to manage diabetes. Therefore, this review aims to deliver an overview of the current conventional medications in diabetes, discovery of newer pharmacological drugs and gene therapy as a potential intervention of diabetes in the future.

Fibroblast growth factor-1 as a mediator of paracrine effects of canine adipose tissue-derived mesenchymal stem cells on in vitro-induced insulin resistance models

Background

In the field of diabetes research, many studies on cell therapy have been conducted using mesenchymal stem cells. This research was intended to shed light on the influence of canine adipose-tissue-derived mesenchymal stem cell conditioned medium (cAT-MSC CM) on in vitro insulin resistance models that were induced in differentiated 3T3-L1 adipocytes and the possible mechanisms involved in the phenomenon.

Results

Gene expression levels of insulin receptor substrate-1 (IRS-1) and glucose transporter type 4 (GLUT4) were used as indicators of insulin resistance. Relative protein expression levels of IRS-1 and GLUT4 were augmented in the cAT-MSC CM treatment group compared to insulin resistance models, indicating beneficial effects of cAT-MSC to DM, probably by actions of secreting factors. With reference to previous studies on fibroblast growth factor-1 (FGF1), we proposed FGF1 as a key contributing factor to the mechanism of action. We added anti-FGF1 neutralizing antibody to the CM-treated insulin resistance models. As a result, significantly diminished protein levels of IRS-1 and GLUT4 were observed, supporting our assumption. Similar results were observed in glucose uptake assay.

Conclusions

Accordingly, this study advocated the potential of FGF-1 from cAT-MSC CM as an alternative insulin sensitizer and discovered a signalling factor associated with the paracrine effects of cAT-MSC.

Electronic supplementary material

The online version of this article (10.1186/s12917-018-1671-1) contains supplementary material, which is available to authorized users.

Protection of mouse pancreatic islet function by co‑culture with hypoxia pre‑treated mesenchymal stromal cells

Ectogenic pancreatic islet transplantation has long been discussed as having the potential to reverse diabetes. The aim of the present study was to evaluate the therapeutic efficacy of co‑transplantation with hypoxia pretreated mesenchymal stem cells (MSCs) and islets in a diabetic mouse model. MSCs were isolated from femoral and tibial bone marrow aspirates from female BALB/c donor mice. MSC proliferation rates and the expression levels of vascular endothelial growth factor A (VEGFA), interleukin (IL)‑6, monocyte chemoattractant protein (MCP)‑1 and matrix metalloproteinase (MMP)‑9 were measured in hypoxic conditions. Subsequently, a streptozotocin‑induced diabetic model was established in BALB/c mice. Glucose tolerance and diabetes reversal rate following co‑transplantation of hypoxia pre‑cultured MSCs and islets were demonstrated at different conditions during transplantation. The present study results demonstrated that MSCs increased their proliferation rate and the secretion of growth‑related cytokines, including VEGFA, IL‑6, MCP‑1 and MMP‑9 in a hypoxic environment. In the diabetes animal model, fewer islets (~250) were required to reverse the impaired glucose tolerance condition in Islets + Hypoxia cultured MSCs transplant group compared with the Islets‑only group (~400 islets) and the Islets + Normal cultured MSCs group (~300 islets). Hypoxia‑cultured MSC co‑transplantation accelerated glycemic utilization following glucose intake. In subjects with hyperglycemia control for islet only transplantation group, MSCs pre‑cultured in hypoxic condition prior to co‑transplantation may potentially improve islet tissue regeneration.

Mesenchymal stem cells pretreated with melatonin ameliorate kidney functions in a rat model of diabetic nephropathy

The aim of this study was to investigate the effect of a regenerative therapy comprising mesenchymal stem cells (MSCs) pretreated with melatonin (MT) as a new therapy for underlying diabetic nephropathy (DN) pathogenesis in a rat model, and its possible effect on autophagy protein Beclin-1. Forty adult male albino Wistar rats were distributed among 4 groups: (i) control, (ii) DN, (iii) MSC-treated, and (iv) treated with MSCs that were pre-incubated in-vitro with MT (5 μmol·L^-1 for 24 h; MSCs + MT). MSCs treatment significantly improved the renal functions and ameliorated the measured underlying DN pathogenesis and elevation of Beclin-1 protein levels compared with the DN group. In-vitro pretreatment of MSCs with MT enhanced proliferation and efficiency, and thus improved the kidney functions by increasing superoxide dismutase (SOD-1) and Beclin-1, and decreasing transforming growth factor (TGF-β) markers in the kidney tissue, compared with the MSC group (P < 0.05). In conclusion: MSCs represent a promising target in DN management, and their effect can be intensified by pretreatment with MT. The elevated levels of Beclin-1 could be a mediator.

Direct comparison of the abilities of bone marrow mesenchymal versus hematopoietic stem cells to reverse hyperglycemia in diabetic NOD.SCID mice

Both bone marrow-derived hematopoietic stem cells (HSC) and mesenchymal stem cells (MSC) improve glycemic control in diabetic mice, but their kinetics and associated changes in pancreatic morphology have not been directly compared. Our goal was to examine the time course of improvements in glucose tolerance and associated changes in β-cell mass and proliferation following transplantation of equivalent numbers of HSC or MSC from the same bone marrow into diabetic non-obese diabetic severe combined immune deficiency (NOD.SCID) mice. We used transgenic mice with a targeted expression of yellow fluorescent protein (YFP) driven by the Vav1 gene promoter to genetically tag HSC and progeny. HSC were separated from bone marrow by fluorescence-activated cell sorting and MSC following cell culture. Equivalent numbers of isolated HSC or MSC were transplanted directly into the pancreas of NOD.SCID mice previously made diabetic with streptozotocin. Glucose tolerance, serum insulin, β-cell mass and β-cell proliferation were examined up to 28 days following transplant. Transplantation with MSC improved glucose tolerance within 7 days and serum insulin levels increased, but with no increase in β-cell mass. Mice transplanted with HSC showed improved glucose tolerance only after 3 weeks associated with increased β-cell proliferation and mass. We conclude that single injections of either MSC or HSC transiently improved glycemic control in diabetic NOD.SCID mice, but with different time courses. However, only HSC infiltrated the islets and were associated with an expanded β-cell mass. This suggests that MSC and HSC have differing mechanisms of action.

Improved insulin-secreting properties of pancreatic islet mesenchymal stem cells by constitutive expression of Pax4 and MafA

For long-term treatment of diabetes type 1, transplantation of insulin-producing beta cells may be a promising method, but the limited number of islets for transplantation requires the development of different approaches. In this study, we aimed to generate betalike insulin-producing cells. For this purpose, MafA, Pax4, and Ngn3 genes were transferred into pancreatic islet-derived mesenchymal stem cells, and the effect of their ectopic expressions on differentiation efficiency was examined. Stemness properties of pancreatic islet stem cells were characterized. The 3 genes were transfected by electroporation and expressed constitutively. The transfected cells were further stimulated to differentiate by using chemical induction. Pax4 expression had significant effects on differentiation into insulin-producing cells. Although it caused morphological alterations in cells, similar to epithelial cells, the insulin secretion levels remained lower than those of the cell line cotransfected with MafA and Pax4. Cotransfection of the 3 transcription factors did not further improve the beta-like cell generation. MafA and Pax4 ectopic expression resulted in improved differentiation efficiency into insulin-secreting cells. However, support of this differentiation process using additional chemical induction may sufice to overcome control by endogenous regulatory pathways.

Reprogramming mouse embryo fibroblasts to functional islets without genetic manipulation

The constant quest for generation of large number of islets aimed us to explore the differentiation potential of mouse embryo fibroblast cells. Mouse embryo fibroblast cells isolated from 12- to 14-day-old pregnant mice were characterized for their surface markers and tri-lineage differentiation potential. They were subjected to serum-free media containing a cocktail of islet differentiating reagents and analyzed for the expression of pancreatic lineage transcripts. The islet-like cell aggregates (ICAs) was confirmed for their pancreatic properties via immunofluorecence for C-peptide, glucagon, and somatostain. They were positive for CD markers-Sca1, CD44, CD73, and CD90 and negative for hematopoietic markers-CD34 and CD45 at both transcription and translational levels. The transcriptional analysis of the ICAs at different day points exhibited up-regulation of islet markers (Insulin, PDX1, HNF3, Glucagon, and Somatostatin) and down-regulation of MSC-markers (Vimentin and Nestin). They positively stained for dithizone, C-peptide, insulin, glucagon, and somatostatin indicating intact insulin producing machinery. In vitro glucose stimulation assay revealed three-fold increase in insulin secretion as compared to basal glucose with insulin content being the same in both the conditions. The preliminary in vivo data on ICA transplantation showed reversal of diabetes in streptozotocin induced diabetic mice. Our results demonstrate for the first time that mouse embryo fibroblast cells contain a population of MSC-like cells which could differentiate into insulin producing cell aggregates. Hence, our study could be extrapolated for isolation of MSC-like cells from human, medically terminated pregnancies to generate ICAs for treating type 1 diabetic patients.

Mesenchymal stem cells and differentiated insulin producing cells are new horizons for pancreatic regeneration in type I diabetes mellitus

BACKGROUND

Diabetes mellitus has become the third human killer following cancer and cardiovascular disease. Millions of patients, often children, suffer from type 1 diabetes (T1D). Stem cells created hopes to regenerate damaged body tissues and restore their function.

AIM

This work aimed at clarifying and comparing the therapeutic potential of differentiated and non-differentiated mesenchymal stem cells (MSCs) as a new line of therapy for T1D.

METHODS

40 Female albino rats divided into group I (control): 10 rats and group II (diabetic), III and IV, 10 rats in each, were injected with streptozotocin (50mg/kg body weight). Group III (MSCs) were transplanted with bone marrow derived MSCs from male rats and group IV (IPCs) with differentiated insulin producing cells. Blood and pancreatic tissue samples were taken from all rats for biochemical and histological studies.

RESULTS

MSCs reduced hyperglycemia in diabetic rats on day 15 while IPCs normalizes blood glucose level on day 7. Histological and morphometric analysis of pancreas of experimental diabetic rats showed improvement in MSCs-treated group but in IPCs-treated group, β-cells insulin immunoreactions were obviously returned to normal, with normal distribution of β-cells in the center and other cells at the periphery. Meanwhile, most of the pathological lesions were still detected in diabetic rats.

CONCLUSION

MSCs transplantation can reduce blood glucose level in recipient diabetic rats. IPCs initiate endogenous pancreatic regeneration by neogenesis of islets. IPCs are better than MSCs in regeneration of β-cells. So, IPCs therapy can be considered clinically to offer a hope for patients suffering from T1D.

CRISPR-targeted genome editing of mesenchymal stem cell-derived therapies for type 1 diabetes: a path to clinical success?

Due to their ease of isolation, differentiation capabilities, and immunomodulatory properties, the therapeutic potential of mesenchymal stem cells (MSCs) has been assessed in numerous pre-clinical and clinical settings. Currently, whole pancreas or islet transplantation is the only cure for people with type 1 diabetes (T1D) and, due to the autoimmune nature of the disease, MSCs have been utilised either natively or transdifferentiated into insulin-producing cells (IPCs) as an alternative treatment. However, the initial success in pre-clinical animal models has not translated into successful clinical outcomes. Thus, this review will summarise the current state of MSC-derived therapies for the treatment of T1D in both the pre-clinical and clinical setting, in particular their use as an immunomodulatory therapy and targets for the generation of IPCs via gene modification. In this review, we highlight the limitations of current clinical trials of MSCs for the treatment of T1D, and suggest the novel clustered regularly interspaced short palindromic repeat (CRISPR) gene-editing technology and improved clinical trial design as strategies to translate pre-clinical success to the clinical setting.

Chitosan-assisted differentiation of porcine adipose tissue-derived stem cells into glucose-responsive insulin-secreting clusters

The unique advantage of easy access and abundance make the adipose-derived stem cells (ADSCs) a promising system of multipotent cells for transplantation and regenerative medicine. Among the available sources, porcine ADSCs (pADSCs) deserve especial attention due to the close resemblance of human and porcine physiology, as well as for the upcoming availability of humanized porcine models. Here, we report on the isolation and conversion of pADSCs into glucose-responsive insulin-secreting cells. We used the stromal-vascular fraction of the dorsal subcutaneous adipose from 9-day-old male piglets to isolate pADSCs, and subjected the cells to an induction scheme for differentiation on chitosan-coated plates. This one-step procedure promoted differentiation of pADSCs into pancreatic islet-like clusters (PILC) that are characterized by the expression of a repertoire of pancreatic proteins, including pancreatic and duodenal homeobox (Pdx-1), insulin gene enhancer protein (ISL-1) and insulin. Upon glucose challenge, these PILC secreted high amounts of insulin in a dose-dependent manner. Our data also suggest that chitosan plays roles not only to enhance the differentiation potential of pADSCs, but also to increase the glucose responsiveness of PILCs. Our novel approach is, therefore, of great potential for transplantation-based amelioration of type 1 diabetes.

The Roles of Insulin-Like Growth Factors in Mesenchymal Stem Cell Niche

Many tissues contain adult mesenchymal stem cells (MSCs), which may be used in tissue regeneration therapies. However, the MSC availability in most tissues is limited which demands expansion in vitro following isolation. Like many developing cells, the state of MSCs is affected by the surrounding microenvironment, and mimicking this natural microenvironment that supports multipotent or differentiated state in vivo is essential to understand for the successful use of MSC in regenerative therapies. Many researchers are, therefore, optimizing cell culture conditions in vitro by altering growth factors, extracellular matrices, chemicals, oxygen tension, and surrounding pH to enhance stem cells self-renewal or differentiation. Insulin-like growth factors (IGFs) system has been demonstrated to play an important role in stem cell biology to either promote proliferation and self-renewal or enhance differentiation onset and outcome, depending on the cell culture conditions. In this review, we will describe the importance of IGFs, IGF-1 and IGF-2, in development and in the MSC niche and how they affect the pluripotency or differentiation towards multiple lineages of the three germ layers.

Enhanced differentiation of human amniotic fluid-derived stem cells into insulin-producing cells in vitro

AIMS/INTRODUCTION

To investigate the ability of human amniotic fluid stem cells (hAFSCs) to differentiate into insulin-producing cells.

MATERIALS AND METHODS

hAFSCs were induced to differentiate into pancreatic cells by a multistep protocol. The expressions of pancreas-related genes and proteins, including pancreatic and duodenal homeobox-1, insulin, and glucose transporter 2, were detected by polymerase chain reaction and immunofluorescence. Insulin secreted from differentiated cells was tested by enzyme-linked immunosorbent assay.

RESULTS

hAFSCs were successfully isolated from amniotic fluid that expressed the pluripotent markers of embryonic stem cells, such as Oct3/4, and mesenchymal stem cells, such as integrin β-1 and ecto-5'-nucleotidase. Here, we first obtained the hAFSCs that expressed pluripotent marker stage-specific embryonic antigen 1. Real-time polymerase chain reaction analysis showed that pancreatic and duodenal homeobox-1, paired box gene 4 and paired box gene 6 were expressed in the early phase of induction, and then stably expressed in the differentiated cells. The pancreas-related genes, such as insulin, glucokinase, glucose transporter 2 and Nkx6.1, were expressed in the differentiated cells. Immunofluorescence showed that these differentiated cells co-expressed insulin, C-peptide, and pancreatic and duodenal homeobox-1. Insulin was released in response to glucose stimulation in a manner similar to that of adult human islets.

CONCLUSIONS

The present study showed that hAFSCs, under selective culture conditions, could differentiate into islet-like insulin-producing cells, which might be used as a potential source for transplantation in patients with type 1 diabetes mellitus.

Mesenchymal stem cell therapy in type 2 diabetes mellitus

Type 2 diabetes mellitus (T2DM), which is characterized by the combination of relative insulin deficiency and insulin resistance, cannot be reversed with existing therapeutic strategies. Transplantation of insulin-producing cells (IPCs) was once thought to be the most promising strategy for treating diabetes, but the pace from the laboratory to clinical application has been obstructed due to its drawbacks. Mesenchymal stem cells (MSCs) harbor differentiation potential, immunosuppressive properties, and anti-inflammatory effects, and they are considered an ideal candidate cell type for treatment of DM. MSC-related research has demonstrated exciting therapeutic effects in glycemic control both in vivo and in vitro, and these results now have been translated into clinical practice. However, some critical potential problems have emerged from current clinical trials. Multi-center, large-scale, double-blind, and placebo-controlled studies with strict supervision are required before MSC transplantation can become a routine therapeutic approach for T2DM. We briefly review the molecular mechanism of MSC treatment for T2DM as well as the merits and drawbacks identified in current clinical trials.

Characterization and Expression of Senescence Marker in Prolonged Passages of Rat Bone Marrow-Derived Mesenchymal Stem Cells

The present study is aimed at optimizing the in vitro culture protocol for generation of rat bone marrow- (BM-) derived mesenchymal stem cells (MSCs) and characterizing the culture-mediated cellular senescence. The initial phase of generation and characterization was conducted using the adherent cells from Sprague Dawley (SD) rat's BM via morphological analysis, growth kinetics, colony forming unit capacity, immunophenotyping, and mesodermal lineage differentiation. Mesenchymal stem cells were successfully generated and characterized as delineated by the expressions of CD90.1, CD44H, CD29, and CD71 and lack of CD11b/c and CD45 markers. Upon induction, rBM-MSCs differentiated into osteocytes and adipocytes and expressed osteocytes and adipocytes genes. However, a decline in cell growth was observed at passage 4 onwards and it was further deciphered through apoptosis, cell cycle, and senescence assays. Despite the enhanced cell viability at later passages (P4-5), the expression of senescence marker, β-galactosidase, was significantly increased at passage 5. Furthermore, the cell cycle analysis has confirmed the in vitro culture-mediated cellular senescence where cells were arrested at the G0/G1 phase of cell cycle. Although the currently optimized protocols had successfully yielded rBM-MSCs, the culture-mediated cellular senescence limits the growth of rBM-MSCs and its potential use in rat-based MSC research.

Mesenchymal stem cells to treat diabetic neuropathy: a long and strenuous way from bench to the clinic

As one of the most common complications of diabetes, diabetic neuropathy often causes foot ulcers and even limb amputations. Inspite of continuous development in antidiabetic drugs, there is still no efficient therapy to cure diabetic neuropathy. Diabetic neuropathy shows declined vascularity in peripheral nerves and lack of angiogenic and neurotrophic factors. Mesenchymal stem cells (MSCs) have been indicated as a novel emerging regenerative therapy for diabetic neuropathy because of their multipotency. We will briefly review the pathogenesis of diabetic neuropathy, characteristic of MSCs, effects of MSC therapies for diabetic neuropathy and its related mechanisms. In order to treat diabetic neuropathy, neurotrophic or angiogenic factors in the form of protein or gene therapy are delivered to diabetic neuropathy, but therapeutic efficiencies are very modest if not ineffective. MSC treatment reverses manifestations of diabetic neuropathy. MSCs have an important role to repair tissue and to lower blood glucose level. MSCs even paracrinely secrete neurotrophic factors, angiogenic factors, cytokines, and immunomodulatory substances to ameliorate diabetic neuropathy. There are still several challenges in the clinical translation of MSC therapy, such as safety, optimal dose of administration, optimal mode of cell delivery, issues of MSC heterogeneity, clinically meaningful engraftment, autologous or allogeneic approach, challenges with cell manufacture, and further mechanisms.

Effects of β-like cell autotransplantation through hepatic arterial intervention on diabetic dogs

Exogenous insulin and EGFP genes were transduced into bone marrow mesenchymal stem cells of beagle dogs using the retroviral vector pMSCV to prepare β-like cells. These cells were autotransplanted into the liver of diabetic dogs through hepatic arterial intervention, and physiological indices before and after transplantation were monitored. Autotransplantation of β-like cells significantly improved blood sugar, insulin levels, and body mass of diabetic dogs (P < 0.01) continuously for over 80 weeks. Since the liver function remained normal and no tumors formed, this method was determined to be reliable and safe. Intrahepatic autotransplantation of β-like cells had long-term, reliable, and safe therapeutic effects on diabetic dogs.

Insulin-Producing Cells Differentiated from Human Bone Marrow Mesenchymal Stem Cells In Vitro Ameliorate Streptozotocin-Induced Diabetic Hyperglycemia

BACKGROUND

The two major obstacles in the successful transplantation of islets for diabetes treatment are inadequate supply of insulin-producing tissue and immune rejection. Induction of the differentiation of human bone marrow-derived mesenchymal stem cells (hMSCs) into insulin-producing cells (IPCs) for autologous transplantation may alleviate those limitations.

METHODS

hMSCs were isolated and induced to differentiate into IPCs through a three-stage differentiation protocol in a defined media with high glucose, nicotinamide, and exendin-4. The physiological characteristics and functions of IPCs were then evaluated. Next, about 3 × 10(6) differentiated cells were transplanted into the renal sub-capsular space of streptozotocin (STZ)-induced diabetic nude mice. Graft survival and function were assessed by immunohistochemistry, TUNEL staining and measurements of blood glucose levels in the mice.

RESULTS

The differentiated IPCs were characterized by Dithizone (DTZ) positive staining, expression of pancreatic β-cell markers, and human insulin secretion in response to glucose stimulation. Moreover, 43% of the IPCs showed L-type Ca2+ channel activity and similar changes in intracellular Ca2+ in response to glucose stimulation as that seen in pancreatic β-cells in the process 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, and PDX-1 without apparent apoptosis in vivo.

CONCLUSIONS

IPCs derived from hMSCs in vitro can ameliorate STZ-induced diabetic hyperglycemia, which indicates that these hMSCs may be a promising approach to overcome the limitations of islet transplantation.

Differentiation of Human Mesenchymal Stem Cells into Insulin Producing Cells by Using A Lentiviral Vector Carrying PDX1

Objective

Type I diabetes is an immunologically-mediated devastation of insulin producing cells (IPCs) in the pancreatic islet. Stem cells that produce β-cells are a new promising tool. Adult stem cells such as mesenchymal stem cells (MSCs) are self renewing multi potent cells showing capabilities to differentiate into ectodermal, mesodermal and endodermal tissues. Pancreatic and duodenal homeobox factor 1 (PDX1) is a master regulator gene required for embryonic development of the pancreas and is crucial for normal pancreatic islets activities in adults.

Materials and Methods

We induced the over-expression of the PDX1 gene in human bone marrow MSCs (BM-MSCs) by Lenti-PDX1 in order to generate IPCs. Next, we examine the ability of the cells by measuring insulin/c-peptide production and INSULIN and PDX1 gene expressions.

Results

After transduction, MSCs changed their morphology at day 5 and gradually differentiated into IPCs. INSULIN and PDX1 expressions were confirmed by real time polymerase chain reaction (RT-PCR) and immunostaining. IPC secreted insulin and C-peptide in the media that contained different glucose concentrations.

Conclusion

MSCs differentiated into IPCs by genetic manipulation. Our result showed that lentiviral vectors could deliver PDX1 gene to MSCs and induce pancreatic differentiation.

Mesenchymal stem cells in the treatment of type 1 diabetes mellitus

Diabetes mellitus type 1 is a form of diabetes mellitus that results from the autoimmune destruction of insulin-producing beta cells in the pancreas. The current gold standard therapy for pancreas transplantation has limitations because of the long list of waiting patients and the limited supply of donor pancreas. Mesenchymal stem cells (MSCs), a relatively new potential therapy in various fields, have already made their mark in the young field of regenerative medicine. Recent studies have shown that the implantation of MSCs decreases glucose levels through paracrine influences rather than through direct transdifferentiation into insulin-producing cells. Therefore, these cells may use pro-angiogenic and immunomodulatory effects to control diabetes following the cotransplantation with pancreatic islets. In this review, we present and discuss new approaches of using MSCs in the treatment of diabetes mellitus type 1.

Pluripotency maintenance of amniotic fluid-derived stem cells cultured on biomaterials

Human amniotic fluid-derived stem cells can maintain their pluripotency when cultured on soft hydrogels.