Mesenchymal stem cells in the treatment of type 1 diabetes mellitus

The effect of diabetes mellitus on differentiation of mesenchymal stem cells into insulin-producing cells

BACKGROUND

Diabetes mellitus (DM) is a global epidemic with increasing incidences. DM is a metabolic disease associated with chronic hyperglycemia. Aside from conventional treatments, there is no clinically approved cure for DM up till now. Differentiating mesenchymal stem cells (MSCs) into insulin-producing cells (IPCs) is a promising approach for curing DM. Our study was conducted to investigate the effect of DM on MSCs differentiation into IPCs in vivo and in vitro.

METHODS

We isolated adipose-derived mesenchymal stem cells (Ad-MSCs) from the epididymal fat of normal and STZ-induced diabetic Sprague-Dawley male rats. Afterwards, the in vitro differentiation of normal-Ad-MSCs (N-Ad-MSCs) and diabetic-Ad-MSCs (DM-Ad-MSCs) into IPCs was compared morphologically then through determining the gene expression of β-cell markers including neurogenin-3 (Ngn-3), homeobox protein (Nkx6.1), musculoaponeurotic fibrosarcoma oncogene homolog A (MafA), and insulin-1 (Ins-1) and eventually, through performing glucose-stimulated insulin secretion test (GSIS). Finally, the therapeutic potential of N-Ad-MSCs and DM-Ad-MSCs transplantation was compared in vivo in STZ-induced diabetic animals.

RESULTS

Our results showed no significant difference in the characteristics of N-Ad-MSCs and DM-Ad-MSCs. However, we demonstrated a significant difference in their abilities to differentiate into IPCs in vitro morphologically in addition to β-cell markers expression, and functional assessment via GSIS test. Furthermore, the abilities of both Ad-MSCs to control hyperglycemia in diabetic rats in vivo was assessed through measuring fasting blood glucose (FBGs), body weight (BW), histopathological examination of both pancreas and liver and immunoexpression of insulin in pancreata of study groups.

CONCLUSION

Our findings reveal the effectiveness of N-Ad-MSCs in differentiating into IPCs in vitro and controlling the hyperglycemia of STZ-induced diabetic rats in vivo compared to DM-Ad-MSCs.

Regulated intestinal microbiota and gut immunity to ameliorate type 1 diabetes mellitus: A novel mechanism for stem cell-based therapy

Although stem cell transplantation is an effective strategy in the treatment of type 1 diabetes mellitus (T1DM), the mechanisms underlying its therapeutic effects remain unclear. We hypothesized that stem cells target gut microbiota and intestinal mucosal immunity to promote therapeutic effects against T1DM. We investigated the effects of human amniotic mesenchymal stem cells (hAMSCs) on intestinal microbiota and mucosal immunity in streptozotocin-induced T1DM mice. hAMSCs promoted significant reductions in blood glucose levels and increased the number of insulin-secreting cells in the T1DM model. Compared with T1DM model mice, 16S rRNA sequencing revealed significant differences in the composition, diversity, and abundance of microbiota in the ileum of hAMSC-treated mice. Bifidobacterium, Prevotella, and Alcaligenes species were among the 15 most abundant differential bacterial species. LC-MS revealed significant changes in ileal metabolites, and among the top 100 differential metabolites identified, we found that a significant increase in taurine was closely associated with hAMSC therapy. Additionally, we detected significant differences between the two groups with respect to the frequency and phenotype of CD4+ T cell subsets in mesenteric lymph nodes, and hAMSCs promoted significant increases in Th2 and Treg cell frequencies and reduced the frequencies of Th1 and Th17 cells. Moreover, correlation analysis revealed pairwise correlations between differential microflora and differential metabolites and immune signatures. hAMSCs thus have positive effects on the microbiota and their metabolites in the ileum and intestinal mucosal immunity in T1DM. Our findings indicate that gut microbiota and intestinal mucosal immunity may play vital roles in the hAMSC-based treatment of T1DM.

Wharton's jelly mesenchymal stem cells: a concise review of their secretome and prospective clinical applications

Accumulating evidence indicates that most primary Wharton's jelly mesenchymal stem cells (WJ-MSCs) therapeutic potential is due to their paracrine activity, i.e., their ability to modulate their microenvironment by releasing bioactive molecules and factors collectively known as secretome. These bioactive molecules and factors can either be released directly into the surrounding microenvironment or can be embedded within the membrane-bound extracellular bioactive nano-sized (usually 30-150 nm) messenger particles or vesicles of endosomal origin with specific route of biogenesis, known as exosomes or carried by relatively larger particles (100 nm-1 μm) formed by outward blebbing of plasma membrane called microvesicles (MVs); exosomes and MVs are collectively known as extracellular vesicles (EVs). The bioactive molecules and factors found in secretome are of various types, including cytokines, chemokines, cytoskeletal proteins, integrins, growth factors, angiogenic mediators, hormones, metabolites, and regulatory nucleic acid molecules. As expected, the secretome performs different biological functions, such as immunomodulation, tissue replenishment, cellular homeostasis, besides possessing anti-inflammatory and anti-fibrotic effects. This review highlights the current advances in research on the WJ-MSCs' secretome and its prospective clinical applications.

Advantages of mesenchymal stem cell over the other stem cells

A stem cell is a particular group of cells that has the extraordinary potential to convert within the body into particular cell types. They are used to regenerate tissues and cells in the body that have been damaged or destroyed by the disease. Stem cells come in three different varieties: adult stem cells, embryonic stem cells and induced pluripotent stem cells (iPSCs). Embryonic stem cells have a high chance of immune rejection and also have ethical dilemmas and iPSCs have genetic instability. Adult stem cells are difficult to analyze and extract for research since they are frequently insufficient in native tissues. However, mesenchymal stem cells (MSC) one of the categories of adult stem cells are stromal cells with a variety of potentials that can differentiate into a wide range of cell types. MSCs can be transplanted into a variety of people without worrying about rejection because they have demonstrated the ability to prevent an adverse reaction from the immune system. These transplants have powerful anti-inflammatory and immunosuppressive effects and greatly enhance the body's inherent healing capacity. While MSCs do not offer treatment for illnesses, the idea behind them is to enable the body to recover sufficiently for a protracted reduction in symptoms. In many cases, this is sufficient to significantly enhance the patient's well-being. Inspite of several advantages some potential long-term concerns connected to MSC therapy are maldifferentiation, immunosuppression and cancerous tumor growth. In this review, we will compare the mesenchymal stem cells with other stem cells with respect to the source of origin, their properties and therapeutic applications, and discuss the MSC's disadvantages.

Tissue engineering approaches and generation of insulin-producing cells to treat type 1 diabetes

Tissue engineering (TE) has become a new effective solution to a variety of medical problems, including diabetes. Mesenchymal stem cells (MSCs), which have the ability to differentiate into endodermal and mesodermal cells, appear to be appropriate for this function. The purpose of this review was to evaluate the outcomes of various researches on the insulin-producing cells (IPCs) generation from MSCs with TE approaches to increase efficacy of type 1 diabetes treatments. The search was performed in PubMed/Medline, Scopus and Embase databases until 2021. Studies revealed that MSCs could also differentiate into IPCs under certain conditions. Therefore, a wide range of protocols have been used for this differentiation, but their effectiveness is very different. Scaffolds can provide a microenvironment that enhances the MSCs to IPCs differentiation, improves their metabolic activity and up-regulate pancreatic-specific transcription factors. They also preserve IPCs architecture and enhance insulin production as well as protect against cell death. This systematic review offers a framework for prospective research based on data. In vitro and in vivo evidence suggests that scaffold-based TE can improve the viability and function of IPCs.

The Therapeutic Potential of Mesenchymal Stem Cells in the Treatment of Diabetes Mellitus

Mesenchymal stem cells (MSCs) exist in many tissues and can differentiate into cells of multiple lineages, such as adipocytes, osteoblasts, or chondrocytes. MSC administration has demonstrated therapeutic potential in various degenerative and inflammatory diseases (e.g., graft-vs.-host disease, multiple sclerosis, Crohn's disease, organ fibrosis, and diabetes mellitus [DM]). The mechanisms involved in the therapeutic effects of MSCs are multifaceted. Generally, implanted MSCs can migrate to sites of injury, where they establish an anti-inflammatory and regenerative microenvironment in damaged tissues. In addition, MSCs can modulate innate and adaptive immune responses through immunosuppressive mechanisms that involve immune cells, inflammatory cytokines, chemokines, and immunomodulatory factors. DM has a high prevalence worldwide; it also contributes to a high rate of mortality worldwide. MSCs offer a promising therapeutic agent to prevent or repair damage from DM and diabetic complications through properties such as multilineage differentiation, homing, promotion of angiogenesis, and immunomodulation (e.g., prevention of oxidative stress, fibrosis, and cell death). In this study, we review current findings regarding the immunomodulatory and regenerative mechanisms of MSCs, as well as their therapeutic applications in DM and DM-related complications.

2D and 3D cultured human umbilical cord-derived mesenchymal stem cell-conditioned medium has a dual effect in type 1 diabetes model in rats: immunomodulation and beta-cell regeneration

BACKGROUND

Type 1 diabetes (T1D) is a T-cell-mediated autoimmune disease characterized by the irreversible destruction of insulin-producing β-cells in pancreatic islets. Helper and cytotoxic T-cells and cytokine production, which is impaired by this process, take a synergetic role in β-cell destruction, and hyperglycemia develops due to insulin deficiency in the body. Mesenchymal stem cells (MSCs) appear like an excellent therapeutic tool for autoimmune diseases with pluripotent, regenerative, and immunosuppressive properties. Paracrine factors released from MSCs play a role in immunomodulation by increasing angiogenesis and proliferation and suppressing apoptosis. In this context, the study aims to investigate the therapeutic effects of MSC's secretomes by conditioned medium (CM) obtained from human umbilical cord-derived MSCs cultured in 2-dimensional (2D) and 3-dimensional (3D) environments in the T1D model.

METHODS

First, MSCs were isolated from the human umbilical cord, and the cells were characterized. Then, two different CMs were prepared by culturing MSCs in 2D and 3D environments. The CM contents were analyzed in terms of total protein, IL-4, IL-10, IL-17, and IFN-λ. In vivo studies were performed in Sprague-Dawley-type rats with an autoimmune T1D model, and twelve doses of CM were administered intraperitoneally for 4 weeks within the framework of a particular treatment model. In order to evaluate immunomodulation, the Treg population was determined in lymphocytes isolated from the spleen after sacrification, and IL-4, IL-10, IL-17, and IFN-λ cytokines were analyzed in serum. Finally, β-cell regeneration was evaluated immunohistochemically by labeling Pdx1, Nkx6.1, and insulin markers, which are critical for the formation of β-cells.

RESULTS

Total protein and IL-4 levels were higher in 3D-CM compared to 2D-CM. In vivo results showed that CMs induce the Treg population and regulate cytokine release. When the immunohistochemical results were evaluated together, it was determined that CM application significantly increased the rate of β-cells in the islets. This increase was at the highest level in the 3D-CM applied group.

CONCLUSION

The dual therapeutic effect of MSC-CM on immunomodulation and homeostasis/regeneration of β-cells in the T1D model has been demonstrated. Furthermore, this effect could be improved by using 3D scaffolds for culturing MSCs while preparing CM.

Pancreatic Transdifferentiation Using β-Cell Transcription Factors for Type 1 Diabetes Treatment

Type 1 diabetes is a chronic illness in which the native beta (β)-cell population responsible for insulin release has been the subject of autoimmune destruction. This condition requires patients to frequently measure their blood glucose concentration and administer multiple daily exogenous insulin injections accordingly. Current treatments fail to effectively treat the disease without significant side effects, and this has led to the exploration of different approaches for its treatment. Gene therapy and the use of viral vectors has been explored extensively and has been successful in treating a range of diseases. The use of viral vectors to deliver β-cell transcription factors has been researched in the context of type 1 diabetes to induce the pancreatic transdifferentiation of cells to replace the β-cell population destroyed in patients. Studies have used various combinations of pancreatic and β-cell transcription factors in order to induce pancreatic transdifferentiation and have achieved varying levels of success. This review will outline why pancreatic transcription factors have been utilised and how their application can allow the development of insulin-producing cells from non β-cells and potentially act as a cure for type 1 diabetes.

New therapeutic approaches of mesenchymal stem cells-derived exosomes

Mesenchymal stem cells (MSCs) have been demonstrated to have a great potential in the treatment of several diseases due to their differentiation and immunomodulatory capabilities and their ability to be easily cultured and manipulated. Recent investigations revealed that their therapeutic effect is largely mediated by the secretion of paracrine factors including exosomes. Exosomes reflect biophysical features of MSCs and are considered more effective than MSCs themselves. Alternative approaches based on MSC-derived exosomes can offer appreciable promise in overcoming the limitations and practical challenges observed in cell-based therapy. Furthermore, MSC-derived exosomes may provide a potent therapeutic strategy for various diseases and are promising candidates for cell-based and cell-free regenerative medicine. This review briefly summarizes the development of MSCs as a treatment for human diseases as well as describes our current knowledge about exosomes: their biogenesis and molecular composition, and how they exert their effects on target cells. Particularly, the therapeutic potential of MSC-derived exosomes in experimental models and recent clinical trials to evaluate their safety and efficacy are summarized in this study. Overall, this paper provides a current overview of exosomes as a new cell-free therapeutic agent.

Clinical efficacy on glycemic control and safety of mesenchymal stem cells in patients with diabetes mellitus: Systematic review and meta-analysis of RCT data

Background

Diabetes mellitus as a chronic metabolic disease is threatening human health seriously. Although numerous clinical trials have been registered for the treatment of diabetes with stem cells, no articles have been published to summarize the efficacy and safety of mesenchymal stem cells (MSCs) in randomized controlled trials (RCTs).

Methods and findings

The aim of this study was to systematically review the evidence from RCTs and, where possible, conduct meta-analyses to provide a reliable numerical summary and the most comprehensive assessment of therapeutic efficacy and safety with MSCs in diabetes. PubMed, Web of Science, Ovid, the Cochrane Library and CNKI were searched. The retrieval time was from establishment of these databases to January 4, 2020. Seven RCTs were eligible for analysis, including 413 participants. Meta-analysis results showed that there were no significant differences in the reduction of fasting plasma glucose (FPG) compared to the baseline [mean difference (MD) = -1.05, 95% confidence interval (CI) (-2.26,0.16), P<0.01, I² = 94%] and the control group [MD = -0.62, 95%CI (-1.46,0.23), P<0.01, I² = 87%]. The MSCs treatment group showed a significant decrease in hemoglobin (Hb) A1c [random-effects, MD = -1.32, 95%CI (-2.06, -0.57), P<0.01, I² = 90%] after treatment. Additionally, HbA1c reduced more significantly in MSC treatment group than in control group [random-effects, MD = -0.87, 95%CI (-1.53, -0.22), P<0.01, I² = 82%] at the end of follow-up. However, as for fasting C-peptide levels, the estimated pooled MD showed that there was no significant increase [MD = -0.07, 95%CI (-0.30, 0.16), P<0.01, I² = 94%] in MSCs treatment group compared with that in control group. Notably, there was no significant difference in the incidence of adverse events between MSCs treatment group and control group [relative risk (RR) = 0.98, 95%CI (0.72, 1.32), P = 0.02, I² = 70%]. The most commonly observed adverse reaction in the MSC treatment group was hypoglycemia (29.95%).

Conclusions

This meta-analysis revealed MSCs therapy may be an effective and safe intervention in subjects with diabetes. However, due to the limited studies, a number of high-quality as well as large-scale RCTs should be performed to confirm these conclusions.

Oxysterols and mesenchymal stem cell biology

Mesenchymal stem cells have the ability to differentiate into several cell types when exposed to determined substances, including oxysterols. Oxysterols are cholesterol products derived from its auto-oxidation by reactive species or from enzymatic action. They are present in the body in low quantities under physiological conditions and exhibit several physiological and pharmacological actions according to both the types of oxysterol and tissue. Some of them are cytotoxic while others have been shown to promote cell differentiation through the action on several different receptors, such as nuclear LXR receptors and Smoothened receptor ligands. Here, we review the main pathways by which oxysterols have been associated with cell differentiation and death of mesenchymal stem cells.

Transcriptome analysis of the transdifferentiation of canine BMSCs into insulin producing cells

Background

Bone marrow mesenchymal stem cells are a potential resource for the clinical therapy of certain diseases. Canine, as a companion animal, living in the same space with human, is an ideal new model for human diseases research. Because of the high prevalence of diabetes, alternative transplantation islets resource (i.e. insulin producing cells) for diabetes treatment will be in urgent need, which makes our research on the transdifferentiation of Bone marrow mesenchymal stem cells into insulin producing cells become more important.

Result

In this study, we completed the transdifferentiation process and achieved the transcriptome profiling of five samples with two biological duplicates, namely, “BMSCs”, “islets”, “stage 1”, “stage 2” and “stage 3”, and the latter three samples were achieved on the second, fifth and eighth day of induction. A total of 11,530 differentially expressed transcripts were revealed in the profiling data. The enrichment analysis of differentially expressed genes revealed several signaling pathways that are essential for regulating proliferation and transdifferentiation, including focal adhesion, ECM-receptor interaction, tight junction, protein digestion and absorption, and the Rap1 signaling pathway. Meanwhile, the obtained protein–protein interaction network and functional identification indicating involvement of three genes, SSTR2, RPS6KA6, and VIP could act as a foundation for further research.

Conclusion

In conclusion, to the best of our knowledge, this is the first survey of the transdifferentiation of canine BMSCs into insulin-producing cells according with the timeline using next-generation sequencing technology. The three key genes we pick out may regulate decisive genes during the development of transdifferentiation of insulin producing cells.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12864-021-07426-3.

Therapeutic potential of mesenchymal stem cells in treating both types of diabetes mellitus and associated diseases

Diabetes mellitus is a common lifestyle disease which can be classified into type 1 diabetes mellitus and type 2 diabetes mellitus. While both result in hyperglycemia due to lack of insulin action and further associated chronic ailments, there is a marked distinction in the cause for each type due to which both require a different prophylaxis. As observed, type 1 diabetes is caused due to the autoimmune action of the body resulting in the destruction of pancreatic islet cells. On the other hand, type 2 diabetes is caused either due to insulin resistance of target cells or lack of insulin production as per physiological requirements. Attempts to cure the disease have been made by bringing drastic changes in the patients' lifestyle; parenteral administration of insulin; prescription of drugs such as biguanides, meglitinides, and amylin; pancreatic transplantation; and immunotherapy. While these attempts cause a certain degree of relief to the patient, none of these can cure diabetes mellitus. However, a new treatment strategy led by the discovery of mesenchymal stem cells and their unique immunomodulatory and multipotent properties has inspired therapies to treat diabetes by essentially reversing the conditions causing the disease. The current review aims to enumerate the role of various mesenchymal stem cells and the different approaches to treat both types of diabetes and its associated diseases as well.

Correction to: The effect of exosomes derived from mesenchymal stem cells in the treatment of induced type 1 diabetes mellitus in rats

In the original publication of the article, the reference citation style in the article was published incorrectly. The journal follows 'Name and Year' style for references. However, they were cited in numbering style incoherent to the references given in the Reference section which were placed in alphabetical order.

The effect of exosomes derived from mesenchymal stem cells in the treatment of induced type 1 diabetes mellitus in rats

AIM

The aim of the current study was to evaluate the therapeutic and regenerative effects of MSCs derived exosomes in the treatment of type 1 DM and to compare its effects with MSCs themselves. The experiment was done on forty albino rats grouped as follows, group (1): Ten healthy rats, group (2): Ten induced type 1 DM rats, group (3): Ten induced type 1 DM rats received exosomes intraperitoneally, and group (4): Ten induced type 1 DM rats received MSCs intraperitoneally. Serum glucose and plasma insulin levels were assessed weekly. QRT-PCR was done to assess regeneration of pancreatic beta cells by measuring insulin, Pdx1, Smad2, Smad3 and TGFβ genes. Additionally, histopathological and immune-histochemical examinations were done to confirm pancreatic tissue regeneration.

RESULTS

Regarding the assessed genes (insulin, Pdx1, Smad2, Smad3 and Tgfβ) gene expression in MSCs treated group showed significant increase compared to diabetic group (p value < 0.001) and gene expression in exosomes treated group was increased significantly compared to diabetic and MSCs treated groups (p value < 0.001). Histopathological and immune-histochemical examination revealed regeneration of pancreatic islets in both treated groups.

CONCLUSION

MSCs Derived exosomes showed superior therapeutic and regenerative results than MSCs themselves.

Therapeutic Potential of Wharton's Jelly Mesenchymal Stem Cells for Diabetes: Achievements and Challenges

Diabetes mellitus (DM) is an alarming metabolic disease in which insulin secreting β-cells are damaged to various extent. Unfortunately, although currently available treatments help to manage the disease, however, patients usually develop complications, as well as decreased life quality and increased mortality. Thus, efficient therapeutic interventions to treat diabetes are urgently warranted. During the past years, mesenchymal stem cells (MSCs) have made their mark as a potential weapon in various regenerative medicine applications. The main fascination about MSCs lies in their potential to exert reparative effects on an amazingly wide spectrum of tissue injury. This is further reinforced by their ease of isolation and large ex vivo expansion capacity, as well as demonstrated multipotency and immunomodulatory activities. Among all the sources of MSCs, those isolated from umbilical cord-Wharton's jelly (WJ-MSCs), have been proved to provide a great source of MSCs. WJ-MSCs do not impose any ethical concerns as those which exist regarding ESCs, and represent a readily available non-invasive source, and hence suggested to become the new gold standard for MSC-based therapies. In the current review, we shall overview achievements, as well as challenges/hurdles which are standing in the way to utilize WJ-MSCs as a novel efficient therapeutic modality for DM.

Mechanism and therapeutic effect of umbilical cord mesenchymal stem cells in inflammatory bowel disease

Inflammatory bowel disease (IBD) is a persistent and chronic disease that is characterized by destructive gastrointestinal (GI) inflammation. Researchers are trying to identify and develop new and more effective treatments with no side effects. Acute and chronic mouse models of IBD were established using dextran sulfate sodium (DSS) solution. To evaluate the efficacy and mechanism, umbilical cord mesenchymal stem cells (UCMSCs) were obtained from Kunming (KM) mice and humans. In the chronic IBD study, the survival rates of the normal control, model, mouse UCMSC (mUCMSC) and human UCMSC (hUCMSC) groups were 100%, 40%, 86.7%, and 100%, respectively. The histopathological scores of the normal control, intraperitoneal injection, intravenous treatment, and model groups were 0.5 ± 0.30, 5.9 ± 1.10, 8.7 ± 1.39, and 8.8 ± 1.33 (p = 0.021). UCMSCs promoted the expression of the intestinal tight junction protein occludin, downregulated the protein expression of the autophagy marker LC3A/B in colon tissue, and upregulated the expression of VEGF-A and VEGFR-1 at the injured site. This study provides an experimental model for elucidating the therapeutic effects of UCMSCs in IBD. We provide a theoretical basis and method for the clinical treatment of IBD using UCMSCs.

Investigating curcumin potential for diabetes cell therapy, in vitro and in vivo study

AIMS

An important obstacle on the way of cell-based therapy is the risk of tumorigenicity in the patients benefit from these transplanted cells due to undifferentiated cells which participate in transplantation. Curcumin, the main compound of spice turmeric -as one of the natural products-was demonstrated to possess effective anti-cancer properties, with no significant effect on normal cells in dose and/or time-dependent manner. Furthermore many studies have been accomplished using curcumin for diabetes treatment. Therefore in this study we examined the efficacy of IPCs treated with curcumin in vivo.

MAIN METHODS

Differentiation efficiency investigated by flowcytometry. RNA extraction and real-time PCR performed for important genes in IPC differentiation and tumorigenesis including Insulin, Nestin, Ngn3, Pdx1, P21, and P53. Finally we investigated the efficiency of these differentiated and treated cells in diabetic rats.

KEY FINDINGS

Our data indicates that nanocurcumin -in a specific dose-reduces the expression of Nestin with no significant effect on insulin expression in mRNA and protein level. Besides blood glucose level of diabetic rats which treated with DNC + cells, decreased from average 350 (mg/dI) to 100 (mg/dI). Checking out the pancreases of these rats, demonstrated that their endocrine segment was rebuilt. Moreover hematoxylin & eosin staining and IF results revealed that the Langerhans Islands were reformed.

SIGNIFICANCE

IPCs' which treated with DNC were able to efficiently control the blood glucose level in diabetic rats which these cells were transplanted to them. Hence Curcumin has the potential to be employed in this kind of cell therapy.

A revealing review of mesenchymal stem cells therapy, clinical perspectives and Modification strategies

Multipotent mesenchymal stem cells (MSCs) have been considerably inspected as effective tool for cell-based therapy of inflammatory, immune-mediated, and degenerative diseases, attributed to their immunomodulatory, immunosuppressive, and regenerative potentials. In the present review, we focus on recent research findings of the clinical applications and therapeutic potential of this cell type, MSCs' mechanisms of therapy, strategies to improve their therapeutic potentials such as manipulations and preconditioning, and potential/unexpected risks which should be considered as a prerequisite step before clinical use. The potential risks would probably include undesirable immune responses, tumor formation and the transmission of incidental agents. Then, we also review some of the milestones in the field, briefly discuss challenges and highlight the new guideline suggested for future directions and perspectives.

MIST1, an Inductive Signal for Salivary Amylase in Mesenchymal Stem Cells

Sjögren’s syndrome (SjS) is an autoimmune disease that destroys the salivary glands and results in severe dry mouth. Mesenchymal stem cell (MSC) transplantation has been recently proposed as a promising therapy for restoring cells in multiple degenerative diseases. We have recently utilized advanced proteomics biochemical assays to identify the key molecules involved in the mesenchymal-epithelial transition (MET) of co-cultured mouse bone-marrow-derived MSCs mMSCs with primary salivary gland cells. Among the multiple transcription factors (TFs) that were differentially expressed, two major TFs were selected: muscle, intestine, and stomach expression-1 (MIST1) and transcription factor E2a (TCF3). These factors were assessed in the current study for their ability to drive the expression of acinar cell marker, alpha-salivary amylase 1 (AMY1), and ductal cell marker, cytokeratin19 (CK19), in vitro. Overexpression of MIST1-induced AMY1 expression while it had little effect on CK19 expression. In contrast, TCF3 induced neither of those cellular markers. Furthermore, we have identified that mMSCs express muscarinic-type 3 receptor (M3R) mainly in the cytoplasm and aquaporin 5 (AQP5) in the nucleus. While MIST1 did not alter M3R levels in mMSCs, a TCF3 overexpression downregulated M3R expressions in mMSCs. The mechanisms for such differential regulation of glandular markers by these TFs warrant further investigation.

Cell Based Therapy for Type 1 Diabetes: Should We Take Hyperglycemia Into Account?

Diabetes mellitus is characterized by long standing hyperglycemia leading to numerous life-threatening complications. For type 1 diabetes mellitus, resulting from selective destruction of insulin producing cells by exaggerated immune reaction, the only effective therapy remains exogenous insulin administration. Despite accurate compliance to treatment of certain patients, transient episodes of hyperglycemia cannot be completely eliminated by this symptomatic treatment. Novel immunotherapeutic approaches based on tolerogenic dendritic cells, T regulatory cells and mesenchymal stem cells (MSCs) have been tested in clinical trials, endeavoring to directly modulate the autoimmune destruction process in pancreas. However, hyperglycemia itself affects the immune system and the final efficacy of cell-based immunotherapies could be affected by the different glycemic control of enrolled patients. The present review explores the impact of hyperglycemia on immune cells while providing greater insight into the molecular mechanisms of high glucose action and subsequent metabolic reprogramming of different immune cells. Furthermore, over-production of mitochondrial reactive oxygen species, formation of advanced glycation end products as a consequence of hyperglycemia and their downstream signalization in immune cells are also discussed. Since hyperglycemia in patients with type 1 diabetes mellitus might have an impact on immune-interventional treatment, the maintenance of a tight glucose control seems to be beneficial in patients considered for cell-based therapy.

Stem cells as a potential therapy for diabetes mellitus: a call-to-action in Latin America

Latin America is a fast-growing region that currently faces unique challenges in the treatment of all forms of diabetes mellitus. The burden of this disease will be even greater in the coming years due, in part, to the large proportion of young adults living in urban areas and engaging in unhealthy lifestyles. Unfortunately, the national health systems in Latin-American countries are unprepared and urgently need to reorganize their health care services to achieve diabetic therapeutic goals. Stem cell research is attracting increasing attention as a promising and fast-growing field in Latin America. As future healthcare systems will include the development of regenerative medicine through stem cell research, Latin America is urged to issue a call-to-action on stem cell research. Increased efforts are required in studies focused on stem cells for the treatment of diabetes. In this review, we aim to inform physicians, researchers, patients and funding sources about the advances in stem cell research for possible future applications in diabetes mellitus. Emerging studies are demonstrating the potential of stem cells for β cell differentiation and pancreatic regeneration. The major economic burden implicated in patients with diabetes complications suggests that stem cell research may relieve diabetic complications. Closer attention should be paid to stem cell research in the future as an alternative treatment for diabetes mellitus.

Ultrasound-targeted microbubble enhances migration and therapeutic efficacy of marrow mesenchymal stem cell on rat middle cerebral artery occlusion stroke model

To investigate the role of ultrasound-targeted microbubbles in the homing effect of bone marrow-derived mesenchymal stem cells (BMSCs) and in the therapeutic efficacy of BMSCs on the ischemic stroke. A middle cerebral artery occlusion (MCAO) model was induced by plug wire preparation. Seventy-two hours after MCAO, the treatment of BMSCs with ultrasound-targeted microbubble was assessed via modified neurological severity score (mNSS), infarct volumes, and cerebral edema. In addition, immunofluorescence was performed to analyze the homing effect of BMSCs with ultrasound-targeted microbubble. We find that BMSCs with ultrasound-targeted microbubble (BMMSCs with ultrasound-targeted microbubble [USMM] group) could significantly ameliorate mNSS, infarct volumes, and cerebral edema of MCAO compared with phosphate buffer saline group, BMSCs alone group (BMSC group), and BMSCs with Ultrasound group (Ultrasound group). Immunofluorescence analysis demonstrated that ultrasound-targeted microbubbles promoted the accumulation of BMSCs in rat MCAO brains. Our findings demonstrated that ultrasound-targeted microbubble could be an effective approach for the accumulation of BMSCs on ischemic stroke, and further improved the therapeutic efficacy of BMSCs on MCAO.

Stem cell therapy in autism: recent insights

Autism spectrum disorders (ASDs) are characterized by core domains: persistent deficits in social communication and interaction; restricted, repetitive patterns of behavior, interests, or activities. ASDs comprise heterogeneous and complex neurodevelopmental pathologies with well-defined inflammatory conditions and immune system dysfunction. Due to neurobiologic changes underlying ASD development, cell-based therapies have been proposed and applied to ASDs. Indeed, stem cells show specific immunologic properties, which make them promising candidates in ASD treatment. This comprehensive up-to-date review focuses on ASD cellular/molecular abnormalities, potentially useful stem cell types, animal models, and current clinical trials on the use of stem cells in treating autism. Limitations are also discussed.

Mesenchymal Stem Cells as New Therapeutic Approach for Diabetes and Pancreatic Disorders

Diabetes is a worldwide disease which actually includes different disorders related to glucose metabolism. According to different epidemiological studies, patients affected by diabetes present a higher risk to develop both acute and chronic pancreatitis, clinical situations which, in turn, increase the risk to develop pancreatic cancer. Current therapies are able to adjust insulin levels according to blood glucose peak, but they only partly reach the goal to abrogate the consequent inflammatory milieu responsible for diabetes-related diseases. In recent years, many studies have investigated the possible use of adult mesenchymal stem cells (MSCs) as alternative therapeutic treatment for diabetes, with promising results due to the manifold properties of these cells. In this review we will critically analyze the many different uses of MSCs for both diabetes treatment and for the reduction of diabetes-related disease development, focusing on their putative molecular mechanisms.

Mesenchymal Stromal/Stem Cells in Regenerative Medicine and Tissue Engineering

As a result of over five decades of investigation, mesenchymal stromal/stem cells (MSCs) have emerged as a versatile and frequently utilized cell source in the fields of regenerative medicine and tissue engineering. In this review, we summarize the history of MSC research from the initial discovery of their multipotency to the more recent recognition of their perivascular identity in vivo and their extraordinary capacity for immunomodulation and angiogenic signaling. As well, we discuss long-standing questions regarding their developmental origins and their capacity for differentiation toward a range of cell lineages. We also highlight important considerations and potential risks involved with their isolation, ex vivo expansion, and clinical use. Overall, this review aims to serve as an overview of the breadth of research that has demonstrated the utility of MSCs in a wide range of clinical contexts and continues to unravel the mechanisms by which these cells exert their therapeutic effects.

Immunomodulatory mechanisms of mesenchymal stem cells and their therapeutic applications

In the recent years, many studies have shown that MSCs must be stimulated by pro-inflammatory cytokines or other immune mediators before they can modulate immune cells in inflamed and damaged tissues. MSCs appear to be involved in inducing several regulatory immune cells, such as Tregs, Bregs, and regulatory NK cells. This new immune milieu created by MSCs may establish a tolerogenic environment that leads to an optimal condition for the treatment of immune diseases. The mechanisms of MSC action to treat immune disorders need to be further investigated in more detail. Since there have been some contradictory outcomes of clinical trials, it is necessary to perform large-scale and randomized clinical studies, such as a phase 3 placebo-controlled double-blind study of a third party MSCs to optimize MSC administration and to prove safety and efficacy of MSC treatment. MSCs offer great therapeutic promise, especially for the treatment of difficult-to-treat immune diseases.

Mesenchymal stromal cells isolated from gestationally diabetic human placenta exhibit insulin resistance, decreased clonogenicity and angiogenesis

Pregnancy is known to be a diabetogenic state. With sedentary lifestyle and wrong dietary choices, gestational diabetes mellitus is on the rise. This raises a concern as placenta is becoming an acceptable choice, as a source of Mesenchymal Stromal Cells (MSCs). In our current study we questioned whether there exists a difference between MSCs isolated from normal and diabetic (Gd-P-MSCs) placenta, as the health of the cells used in therapy is of prime importance. We isolated and verified the Gd-P-MSCs based on their surface markers and differentiation potential. We looked at viability and proliferation and did not see a difference between the two. We analysed the glucose uptake potential of these cells by assessing the remnant glucose in the media, glucose within the cells by 2-NBDG and by glycogen storage. Despite only a slight downregulation of mRNA expression levels of glucose transporters, Gd-P-MSCs exhibited decreased glucose uptake even upon insulin stimulation and decreased glycogen storage, indicative of an insulin resistant state. We then assessed the colony forming ability of the cells and found a decreased clonogenicity in Gd-P-MSCs. We also examined the angiogenic potential of the cells by tube formation. Gd-P-MSCs showed decreased angiogenic potential when compared to normal cells. Thus we show for the first time, the effect of gestational diabetes on cells isolated from the chorionic villi of term placenta. Gd-P-MSCs are indeed insulin resistant, exhibit decreased clonogenicity and angiogenic potential. The present investigation is of relevance to the choice of sample for MSC isolation for therapeutic purposes.

Immunomodulatory oligonucleotide IMT504: Effects on mesenchymal stem cells as a first-in-class immunoprotective/immunoregenerative therapy

The immune responses of humans and animals to insults (i.e., infections, traumas, tumoral transformation and radiation) are based on an intricate network of cells and chemical messengers. Abnormally high inflammation immediately after insult or abnormally prolonged pro-inflammatory stimuli bringing about chronic inflammation can lead to life-threatening or severely debilitating diseases. Mesenchymal stem cell (MSC) transplant has proved to be an effective therapy in preclinical studies which evaluated a vast diversity of inflammatory conditions. MSCs lead to resolution of inflammation, preparation for regeneration and actual regeneration, and then ultimate return to normal baseline or homeostasis. However, in clinical trials of transplanted MSCs, the expectations of great medical benefit have not yet been fulfilled. As a practical alternative to MSC transplant, a synthetic drug with the capacity to boost endogenous MSC expansion and/or activation may also be effective. Regarding this, IMT504, the prototype of a major class of immunomodulatory oligonucleotides, induces in vivo expansion of MSCs, resulting in a marked improvement in preclinical models of neuropathic pain, osteoporosis, diabetes and sepsis. IMT504 is easily manufactured and has an excellent preclinical safety record. In the small number of patients studied thus far, IMT504 has been well-tolerated, even at very high dosage. Further clinical investigation is necessary to demonstrate the utility of IMT504 for resolution of inflammation and regeneration in a broad array of human diseases that would likely benefit from an immunoprotective/immunoregenerative therapy.

Recipient Glycemic Micro-environments Govern Therapeutic Effects of Mesenchymal Stem Cell Infusion on Osteopenia

Therapeutic effects of mesenchymal stem cell (MSC) infusion have been revealed in various human disorders, but impacts of diseased micro-environments are only beginning to be noticed. Donor diabetic hyperglycemia is reported to impair therapeutic efficacy of stem cells. However, whether recipient diabetic condition also affects MSC-mediated therapy is unknown. We and others have previously shown that MSC infusion could cure osteopenia, particularly in ovariectomized (OVX) mice. Here, we discovered impaired MSC therapeutic effects on osteopenia in recipient type 1 diabetes (T1D). Through intensive glycemic control by daily insulin treatments, therapeutic effects of MSCs on osteopenia were maintained. Interestingly, by only transiently restoration of recipient euglycemia using single insulin injection, MSC infusion could also rescue T1D-induced osteopenia. Conversely, under recipient hyperglycemia induced by glucose injection in OVX mice, MSC-mediated therapeutic effects on osteopenia were diminished. Mechanistically, recipient hyperglycemic micro-environments reduce anti-inflammatory capacity of MSCs in osteoporotic therapy through suppressing MSC interaction with T cells via the Adenosine monophosphate-activated protein kinase (AMPK) pathway. We further revealed in diabetic micro-environments, double infusion of MSCs ameliorated osteopenia by anti-inflammation, attributed to the first transplanted MSCs which normalized the recipient glucose homeostasis. Collectively, our findings uncover a previously unrecognized role of recipient glycemic conditions controlling MSC-mediated therapy, and unravel that fulfillment of potent therapeutic effects of MSCs requires tight control of recipient micro-environments.

Activation, homing, and role of the mesenchymal stem cells in the inflammatory environment

Human mesenchymal stem cells (MSCs) are considered to be a promising source of cells in regenerative medicine. They have large potential to differentiate into various tissue-specific populations and may be isolated from diverse tissues in desired quantities. As cells of potential autologous origin, they allow recipients to avoid the alloantigen responses. They also have the ability to create immunomodulatory microenvironment, and thus help to minimize organ damage caused by the inflammation and cells activated by the immune system. Our knowledge about the reparative, regenerative, and immunomodulatory properties of MSCs is advancing. At present, there is a very comprehensible idea on how MSCs affect the immune system, particularly in relation to the tissue and organ damage on immunological basis. Hitherto a number of effective mechanisms have been described by which MSCs influence the immune responses. These mechanisms include a secretion of soluble bioactive agents, an induction of regulatory T cells, modulation of tolerogenic dendritic cells, as well as induction of anergy and apoptosis. MSCs are thus able to influence both innate and adaptive immune responses. Soluble factors that are released into local microenvironment with their subsequent paracrine effects are keys to the activation. As a result, activated MSCs contribute to the restoration of damaged tissues or organs through various mechanisms facilitating reparative and regenerative processes as well as through immunomodulation itself and differentiation into the cells of the target tissue.

Infusion with Human Bone Marrow-derived Mesenchymal Stem Cells Improves β-cell Function in Patients and Non-obese Mice with Severe Diabetes

Mesenchymal stem cells (MSCs) transplantation is a promising therapeutic strategy for type 1 diabetes (T1D). However, little is known on whether MSC transplantation can benefit T1D patients with ketoacidosis and its potential actions. Here, we show that infusion with bone marrow MSCs preserves β-cell function in some T1D patients with ketoacidosis by decreasing exogenous insulin requirement and increasing plasma C-peptide levels up to 1–2 years. MSC transplantation increased plasma and islet insulin contents in non-obese diabetic (NOD) mice with severe diabetes. In comparison with severe diabetes controls, MSC infusion reduced insulitis, decreased pancreatic TNF-α, and increased IL-10 and TGF-β1 expression in NOD mice. MSC infusion increased the percentages of splenic Tregs and levels of plasma IL-4, IL-10 and TGF-β1, but reduced the percentages of splenic CD8⁺ T and levels of plasma IFN-γ, TNF-α and IL-17A in NOD mice. Finally, infused MSCs predominantly accumulated in pancreatic tissues at 28 days post infusion. The effects of MSCs on preserving β-cell function and modulating inflammation tended to be dose-dependent and multiple doses of MSCs held longer effects in NOD mice. Hence, MSC transplantation preserved β-cell function in T1D patients and NOD mice with severe diabetes by enhancing Treg responses.

Liraglutide Enhances the Efficacy of Human Mesenchymal Stem Cells in Preserving Islet β-cell Function in Severe Non-obese Diabetic Mice

Glucagon-like peptide 1 (GLP-1) can promote islet β-cell replication and function, and mesenchymal stem cells (MSCs) can inhibit T cell autoimmunity. This study aimed at testing the dynamic distribution of infused human MSCs and therapeutic effect of combined MSCs and Liraglutide, a long-acting GLP-1 analogue, on preserving β-cell function in severe non-obese diabetic (NOD) mice. We found that infused MSCs accumulated in the pancreas at 4 weeks post infusion, which was not affected by Liraglutide treatment. Liraglutide significantly enhanced the function of MSCs to preserve islet β-cells by reducing glucose level at 30 minutes post glucose challenge and increasing the contents and secretion of insulin by islet β-cells in severe diabetic NOD mice. Infusion with MSCs significantly reduced insulitis scores, but increased the frequency of splenic Tregs, accompanied by reducing the levels of plasma IFN-γ and TNF-α and elevating the levels of plasma IL-10 and transforming growth factor-β1 (TGF-β1) in NOD mice. Although Liraglutide mitigated MSC-mediated changes in the frequency of Tregs and the levels of plasma IL-10, Liraglutide significantly increased the levels of plasma TGF-β1 in severe diabetic NOD mice. Therefore, our findings suggest that Liraglutide may enhance the therapeutic efficacy of MSCs in treatment of severe type 1 diabetes.