Overexpression of apelin in Wharton' jelly mesenchymal stem cell reverses insulin resistance and promotes pancreatic β cell proliferation in type 2 diabetic rats

Mesenchymal stromal cells ameliorate mitochondrial dysfunction in α cells and hyperglucagonemia in type 2 diabetes via SIRT1/FoxO3a signaling

Dysregulation of α cells results in hyperglycemia and hyperglucagonemia in type 2 diabetes mellitus (T2DM). Mesenchymal stromal cell (MSC)-based therapy increases oxygen consumption of islets and enhances insulin secretion. However, the underlying mechanism for the protective role of MSCs in α-cell mitochondrial dysfunction remains unclear. Here, human umbilical cord MSCs (hucMSCs) were used to treat 2 kinds of T2DM mice and αTC1-6 cells to explore the role of hucMSCs in improving α-cell mitochondrial dysfunction and hyperglucagonemia. Plasma and supernatant glucagon were detected by enzyme-linked immunosorbent assay (ELISA). Mitochondrial function of α cells was assessed by the Seahorse Analyzer. To investigate the underlying mechanisms, Sirtuin 1 (SIRT1), Forkhead box O3a (FoxO3a), glucose transporter type1 (GLUT1), and glucokinase (GCK) were assessed by Western blotting analysis. In vivo, hucMSC infusion improved glucose and insulin tolerance, as well as hyperglycemia and hyperglucagonemia in T2DM mice. Meanwhile, hucMSC intervention rescued the islet structure and decreased α- to β-cell ratio. Glucagon secretion from αTC1-6 cells was consistently inhibited by hucMSCs in vitro. Meanwhile, hucMSC treatment activated intracellular SIRT1/FoxO3a signaling, promoted glucose uptake and activation, alleviated mitochondrial dysfunction, and enhanced ATP production. However, transfection of SIRT1 small interfering RNA (siRNA) or the application of SIRT1 inhibitor EX-527 weakened the therapeutic effects of hucMSCs on mitochondrial function and glucagon secretion. Our observations indicate that hucMSCs mitigate mitochondrial dysfunction and glucagon hypersecretion of α cells in T2DM via SIRT1/FoxO3a signaling, which provides novel evidence demonstrating the potential for hucMSCs in treating T2DM.

Development, regeneration, and physiological expansion of functional β-cells: Cellular sources and regulators

Pancreatic regeneration is a complex process observed in both normal and pathological conditions. The aim of this review is to provide a comprehensive understanding of the emergence of a functionally active population of insulin-secreting β-cells in the adult pancreas. The renewal of β-cells is governed by a multifaceted interaction between cellular sources of genetic and epigenetic factors. Understanding the development and heterogeneity of β-cell populations is crucial for functional β-cell regeneration. The functional mass of pancreatic β-cells increases in situations such as pregnancy and obesity. However, the specific markers of mature β-cell populations and postnatal pancreatic progenitors capable of increasing self-reproduction in these conditions remain to be elucidated. The capacity to regenerate the β-cell population through various pathways, including the proliferation of pre-existing β-cells, β-cell neogenesis, differentiation of β-cells from a population of progenitor cells, and transdifferentiation of non-β-cells into β-cells, reveals crucial molecular mechanisms for identifying cellular sources and inducers of functional cell renewal. This provides an opportunity to identify specific cellular sources and mechanisms of regeneration, which could have clinical applications in treating various pathologies, including in vitro cell-based technologies, and deepen our understanding of regeneration in different physiological conditions.

Therapeutic potential: The role of mesenchymal stem cells from diverse sources and their derived exosomes in diabetic nephropathy

Diabetic nephropathy (DN) is one of the most common microvascular complications in diabetic patients, with its incidence continuously increasing in recent years. DN causes renal tissue damage and functional decline, expedites the aging process of the kidneys, and may ultimately progress leading to end-stage renal disease, severely impacting the patient's quality of life and prognosis. Mesenchymal stem cells (MSCs) are highly valued for their multipotent differentiation, paracrine functions, immunomodulatory effects, and capacity for tissue repair. Particularly, exosomes (Exo) derived from MSCs (MSCs-Exo) are rich in bioactive molecules and facilitate intercellular communication, participating in various physiological and pathological processes. MSCs and MSCs-Exo, in particular, have been demonstrated to have therapeutic effects in DN treatment research by encouraging tissue repair, fibrosis inhibition, and inflammation reduction. Research has shown that MSCs and MSCs-Exo have therapeutic effects in DN treatment by promoting tissue repair, inhibiting fibrosis, and reducing inflammation. Recent studies underscore the potential of MSCs and MSCs-Exo, highlighting their broad applicability in DN treatment. This review aims to provide a comprehensive summary of the scientific developments in treating DN using MSCs and MSCs-Exo from diverse sources, while also exploring their future therapeutic possibilities in detail.

Enhancing insulin sensitivity in type 2 diabetes mellitus using apelin-loaded small extracellular vesicles from Wharton's jelly-derived mesenchymal stem cells: a novel therapeutic approach

BACKGROUND

Type 2 diabetes mellitus (T2DM), characterized by β-cell dysfunction and insulin resistance (IR), presents considerable treatment challenges. Apelin is an adipocyte-derived factor that shows promise in improving IR; however, it is limited by poor targeting and a short half-life. In the present study, engineered small extracellular vesicles (sEVs) derived from Wharton's jelly-derived mesenchymal stem cells (WJ-MSCs) loaded with apelin were used to address the limitations of the therapeutic application of apelin.

METHODS

WJ-MSCs were transduced to obtain engineered sEVs loaded with overexpressed apelin (apelin-MSC-sEVs) and the control sEVs (MSC-sEVs). T2DM mice were injected with apelin-MSC-sEVs and MSC-sEVs, and blood glucose monitoring, glucose and insulin tolerance tests, confocal microscopy, and immunocytochemical analysis were performed. IR models of 3T3-L1 adipocytes were employed to detect GLUT4 expression in each group using western blotting; the affected pathways were determined by measuring the changes in Akt and AMPK signaling and phosphorylation.

RESULTS

Upon successful engineering, WJ-MSCs demonstrated significant overexpression of apelin. The genetic modification did not adversely impact the characteristics of sEVs, ranging from surface protein markers, morphology, to particle size, but generated apelin-overexpressed sEVs. Apelin-MSC-sEVs treatment resulted in notable enhancement of Akt and AMPK pathway activities within 3T3-L1 adipocytes and adipose tissues of T2DM mice. Furthermore, the apelin-loaded sEVs significantly reduced plasma glucose levels, increased pancreatic β-cell proliferation, improved insulin and glucose tolerance, and modulated pro-inflammatory cytokine profiles, compared to mice treated with the control sEVs.

CONCLUSION

Our study developed novel genetically engineered apelin-loaded sEVs derived from WJ-MSCs, and demonstrated their potent role in augmenting insulin sensitivity and regulating inflammatory responses, highlighting their therapeutic promise in T2DM management. The findings open new avenues for the development of clinically viable treatments for T2DM in humans using the apelin-loaded sEVs.

Treatment of type 2 diabetes mellitus with stem cells and antidiabetic drugs: a dualistic and future-focused approach

Type 2 Diabetes Mellitus (T2DM) accounts for more than 90% of total diabetes mellitus cases all over the world. Obesity and lack of balance between energy intake and energy expenditure are closely linked to T2DM. Initial pharmaceutical treatment and lifestyle interventions can at times lead to remission but usually help alleviate it to a certain extent and the condition remains, thus, recurrent with the patient being permanently pharmaco-dependent. Mesenchymal stromal cells (MSCs) are multipotent, self-renewing cells with the ability to secrete a variety of biological factors that can help restore and repair injured tissues. MSC-derived exosomes possess these properties of the original stem cells and are potentially able to confer superior effects due to advanced cell-to-cell signaling and the presence of stem cell-specific miRNAs. On the other hand, the repository of antidiabetic agents is constantly updated with novel T2DM disease-modifying drugs, with higher efficacy and increasingly convenient delivery protocols. Delving deeply, this review details the latest progress and ongoing studies related to the amalgamation of stem cells and antidiabetic drugs, establishing how this harmonized approach can exert superior effects in the management and potential reversal of T2DM.

The Interplay of Adipokines and Pancreatic Beta Cells in Metabolic Regulation and Diabetes

The interplay between adipokines and pancreatic beta cells, often referred to as the adipo-insular axis, plays a crucial role in regulating metabolic homeostasis. Adipokines are signaling molecules secreted by adipocytes that have profound effects on several physiological processes. Adipokines such as adiponectin, leptin, resistin, and visfatin influence the function of pancreatic beta cells. The reciprocal communication between adipocytes and beta cells is remarkable. Insulin secreted by beta cells affects adipose tissue metabolism, influencing lipid storage and lipolysis. Conversely, adipokines released from adipocytes can influence beta cell function and survival. Chronic obesity and insulin resistance can lead to the release of excess fatty acids and inflammatory molecules from the adipose tissue, contributing to beta cell dysfunction and apoptosis, which are key factors in developing type 2 diabetes. Understanding the complex interplay of the adipo-insular axis provides insights into the mechanisms underlying metabolic regulation and pathogenesis of metabolic disorders. By elucidating the molecular mediators involved in this interaction, new therapeutic targets and strategies may emerge to reduce the risk and progression of diseases, such as type 2 diabetes and its associated complications. This review summarizes the interactions between adipokines and pancreatic beta cells, and their roles in the pathogenesis of diabetes and metabolic diseases.

Lactobacillus gasseri CKCC1913 mediated modulation of the gut-liver axis alleviated insulin resistance and liver damage induced by type 2 diabetes

Type 2 diabetes mellitus (T2DM) is a chronic metabolic disorder characterized by dysregulation of lipid metabolism, insulin resistance, and gut microbiota disorder. Compared to drug interventions, probiotic interventions may have a more enduring effect without producing any side effects. Thus, the potential of probiotics as a therapeutic approach for diabetes and other metabolic disorders has gained increasing attention in recent years. In this study, we evaluated the therapeutic efficacy of Lactobacillus gasseri CKCC1913, a potential probiotic strain, in high-fat diet-induced insulin-resistant diabetes using the C57BL/6J mouse animal model. From the results, L. gasseri CKCC1913 has been shown to increase glucose tolerance, reduce fasting blood glucose levels in diabetic mice, and reduce the expression of pro-inflammatory cytokines, such as TNF-α and IL-6. Besides, L. gasseri CKCC1913 intervention effectively alleviated oxidative stress damage by increasing SOD activity, decreasing MDA levels, reducing insulin resistance, and improving dyslipidemia caused by diabetes. The potential mechanism of L. gasseri CKCC1913 in improving metabolic health and alleviating diabetes involves an increased abundance of beneficial bacteria, such as Parabacteroides merdae, which directly produce short-chain fatty acids that help regulate immune cells and reduce inflammation. SCFAs also enter the bloodstream and promote antioxidant enzyme activity in the liver, protecting against oxidative damage. Additionally, L. gasseri CKCC1913 influences local bacterial metabolism pathways, such as the superpathway of unsaturated fatty acid biosynthesis, leading to an increase in unsaturated fatty acids, increasing high-density lipoprotein cholesterol (HDL-C) levels and improving lipid metabolism and glucose control in diabetic mice. In summary, in this study, L. gasseri CKCC1913 and its potential impact on metabolic health highlight the promising potential of probiotics as a therapeutic approach for diabetes. Future research should focus on identifying the optimal dose and duration, investigating the long-term effects and mechanisms of action, and exploring the potential use of probiotics as an adjunct to other therapies or in preventing metabolic disorders.

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.

Perinatal Stem Cell Therapy to Treat Type 1 Diabetes Mellitus: A Never-Say-Die Story of Differentiation and Immunomodulation

Human term placenta and other postpartum-derived biological tissues are promising sources of perinatal cells with unique stem cell properties. Among the massive current research on stem cells, one medical focus on easily available stem cells is to exploit them in the design of immunotherapy protocols, in particular for the treatment of chronic non-curable human diseases. Type 1 diabetes is characterized by autoimmune destruction of pancreatic beta cells and perinatal cells can be harnessed both to generate insulin-producing cells for beta cell replenishment and to regulate autoimmune mechanisms via immunomodulation capacity. In this study, the strong points of cells derived from amniotic epithelial cells and from umbilical cord matrix are outlined and their potential for supporting cell therapy development. From a basic research and expert stem cell point of view, the aim of this review is to summarize information regarding the regenerative medicine field, as well as describe the state of the art on possible cell therapy approaches for diabetes.

Serum CTRP9 and high-molecular weight adiponectin are associated with ischemic stroke

Background

C1q/TNF-related protein 9 (CTRP9) and adiponectin (APN) have beneficial metabolic regulatory and vasoprotective effects. This study explored alteration of CTRP9 and APN multimers during onset of ischemic stroke and development, to provide novel clinical and experimental basis for recognition and prevention of ischemic stroke.

Methods

There were 269 patients with ischemic stroke and 182 control subjects included in this study. Serum levels of CTRP9 and APN multimers in different disease stages were measured.

Results

Serum CTRP9, total APN (tAPN), and high-molecular weight (HMW) APN decreased gradually in stage I (acute stage, within 72 h of onset) of ischemic stroke and increased during stage III (11th day to one month) and stage IV (1 month after), compared to control. In the non-hyperlipidemia group, serum CTRP9, tAPN, and HMW were decreased in ischemic stroke patients compared to control (P < 0.05). Serum CTRP9 is closely related to serum tAPN and HMW (r = 0.992, 0.991). Serum CTRP9 are protective against ischemic stroke (OR = 0.400, 95% CI 0.197–0.810, P < 0.05).

Conclusions

Lower serum CTRP9, tAPN, LMW, and HMW are significantly associated with increased ischemic stroke risk in non-hyperlipidemia subjects. CTRP9, tAPN, and HMW isoforms may be valuable clinical indicators for patients with ischemic stroke.

Therapeutic role of mesenchymal stem cells (MSCs) in diabetic kidney disease (DKD)

Findings of preclinical studies and recent phase I/II clinical trials have shown that mesenchymal stem cells (MSCs) play a significant role in the development of diabetic kidney disease (DKD). Thus, MSCs have attracted increasing attention as a novel regenerative therapy for kidney diseases. This review summarizes recent literature on the roles and potential mechanisms, including hyperglycemia regulation, anti-inflammation, anti-fibrosis, pro-angiogenesis, and renal function protection, of MSC-based treatment methods for DKD. This review provides novel insights into understanding the pathogenesis of DKD and guiding the development of biological therapies.

Adipose Tissue Secretion Pattern Influences β-Cell Wellness in the Transition from Obesity to Type 2 Diabetes

The dysregulation of the β-cell functional mass, which is a reduction in the number of β-cells and their ability to secure adequate insulin secretion, represents a key mechanistic factor leading to the onset of type 2 diabetes (T2D). Obesity is recognised as a leading cause of β-cell loss and dysfunction and a risk factor for T2D. The natural history of β-cell failure in obesity-induced T2D can be divided into three steps: (1) β-cell compensatory hyperplasia and insulin hypersecretion, (2) insulin secretory dysfunction, and (3) loss of β-cell mass. Adipose tissue (AT) secretes many hormones/cytokines (adipokines) and fatty acids that can directly influence β-cell function and viability. As this secretory pattern is altered in obese and diabetic patients, it is expected that the cross-talk between AT and pancreatic β-cells could drive the maintenance of the β-cell integrity under physiological conditions and contribute to the reduction in the β-cell functional mass in a dysmetabolic state. In the current review, we summarise the evidence of the ability of the AT secretome to influence each step of β-cell failure, and attempt to draw a timeline of the alterations in the adipokine secretion pattern in the transition from obesity to T2D that reflects the progressive deterioration of the β-cell functional mass.

Evaluation of hypoglycemic therapeutics and nutritional supplementation for type 2 diabetes mellitus management: An insight on molecular approaches

OBJECTIVE

This review aims to summarize the current management of type 2 diabetes principles, including oral hypoglycemic agents, types of insulin administration, diet maintenance, and various molecular approaches.

METHODS

A literature search was conducted in different databases such as Scopus, ScienceDirect, Google Scholar, and Web of Science by using the following keywords: type-2 diabetes mellitus (T2DM), first-line and second-line treatment, oral hypoglycemic agents, insulin administration, diet/nutritional therapy, gene and stem cell therapy, and diabetic complications.

RESULTS

The first-line treatment of T2DM includes administering oral hypoglycemic agents (OHAs) and second-line treatment by insulin therapy and some OHAs like Sulfonylurea's (SU). The oral hypoglycemic or oral antidiabetic drugs have the function of lowering glucose in the blood. Insulin therapy is recommended for people with A1C levels > 7.0, and insulin administration is evolved drastically from the syringe, pump, pen, inhalation, insulin jet, and patch. The use of OHAs and insulin therapy during glycemic control has a severe effect on weight gain and other side effects. Hence, diet maintenance (macro and micronutrients) and nutritional therapy guidelines were also reviewed/recommended for safe T2DM management. Besides, the recent progress in molecular approaches that focuses on identifying new targets for T2DM (i.e.) consisting of gene therapy, stem cell therapy, and the modulation of insulin signaling pathways for the regulation of glucose storage and uptake also discussed.

CONCLUSION

The analysis of all these key factors is necessary to develop a potential agent to cure T2DM and suggest that a combination of therapies will pave the way for advanced management of T2DM.

Apelin pathway in cardiovascular, kidney, and metabolic diseases: Therapeutic role of apelin analogs and apelin receptor agonists

The apelin/apelin receptor (ApelinR) signal transduction pathway exerts essential biological roles, particularly in the cardiovascular system. Disturbances in the apelin/ApelinR axis are linked to vascular, heart, kidney, and metabolic disorders. Therefore, the apelinergic system has surfaced as a critical therapeutic strategy for cardiovascular diseases (including pulmonary arterial hypertension), kidney disease, insulin resistance, hyponatremia, preeclampsia, and erectile dysfunction. However, apelin peptides are susceptible to rapid degradation through endogenous peptidases, limiting their use as therapeutic tools and translational potential. These proteases include angiotensin converting enzyme 2, neutral endopeptidase, and kallikrein thereby linking the apelin pathway with other peptide systems. In this context, apelin analogs with enhanced proteolytic stability and synthetic ApelinR agonists emerged as promising pharmacological alternatives. In this review, we focus on discussing the putative roles of the apelin pathway in various physiological systems from function to dysfunction, and emphasizing the therapeutic potential of newly generated metabolically stable apelin analogs and non-peptide ApelinR agonists.

Andrographolide, a novel inducer of apelin gene expression

ETHNOPHARMACOLOGICAL RELEVANCE

Andrographis paniculata (A. paniculata) has been used as a traditional medicine in Asia and Scandinavia for centuries to remedy several illnesses. It has since been shown to possess antibacterial, antifungal, antiviral, anti-neoplasm, hepatoprotective, hypoglycemic, hypocholesterolemic, and energetic effects.

AIMS OF THE STUDY

This study sought to investigate the effect of Andrographolide on apelin gene expression and serum levels of glucose.

MATERIALS AND METHODS

In this study, 18 male rats were used. They were divided into three groups of six, including i) negative control group, ii) 3.5 mg/kg Andrographolide group, and iii) 7 mg/kg Andrographolide group. Apelin gene expression was investigated by real-time PCR method. Serum levels of glucose were measured by the photometric method.

RESULTS

The results of this study revealed that 3.5 and 7 mg doses per kg of body weight of andrographolide, for six days, significantly increased hepatic expression of apelin gene in male Wistar rats, as compared with the control group (p < 0.05). Serum levels of glucose at doses of 3.5 and 7 mg/kg of andrographolide, and in the control group, were 71.5 ± 8.96, 51.5 ± 2.64, and 93.87 ± 14.27 mg/dl, respectively. Andrographolide induced a decrease in serum levels of HDL-c and an increase in LDL-c/HDL-c ratio.

CONCLUSIONS

Our results suggest that Andrographolide can elicit an increase of hepatic apelin gene expression and a decrease in serum levels of blood glucose.

Ontology of the apelinergic system in mouse pancreas during pregnancy and relationship with β-cell mass

The apelin receptor (Aplnr) and its ligands, Apelin and Apela, contribute to metabolic control. The insulin resistance associated with pregnancy is accommodated by an expansion of pancreatic β-cell mass (BCM) and increased insulin secretion, involving the proliferation of insulin-expressing, glucose transporter 2-low (Ins+Glut2LO) progenitor cells. We examined changes in the apelinergic system during normal mouse pregnancy and in pregnancies complicated by glucose intolerance with reduced BCM. Expression of Aplnr, Apelin and Apela was quantified in Ins+Glut2LO cells isolated from mouse pancreata and found to be significantly higher than in mature β-cells by DNA microarray and qPCR. Apelin was localized to most β-cells by immunohistochemistry although Aplnr was predominantly associated with Ins+Glut2LO cells. Aplnr-staining cells increased three- to four-fold during pregnancy being maximal at gestational days (GD) 9-12 but were significantly reduced in glucose intolerant mice. Apelin-13 increased β-cell proliferation in isolated mouse islets and INS1E cells, but not glucose-stimulated insulin secretion. Glucose intolerant pregnant mice had significantly elevated serum Apelin levels at GD 9 associated with an increased presence of placental IL-6. Placental expression of the apelinergic axis remained unaltered, however. Results show that the apelinergic system is highly expressed in pancreatic β-cell progenitors and may contribute to β-cell proliferation in pregnancy.

Efficacy of mesenchymal stem cell transplantation therapy for type 1 and type 2 diabetes mellitus: a meta-analysis

BACKGROUND

This meta-analysis was first conducted to evaluate the efficacy and safety of transplantation of mesenchymal stem cells in the treatment of type 1 and type 2 diabetes mellitus (T1DM and T2DM).

METHODS

We systematically searched PubMed, ScienceDirect, Google Scholar, CNKI, EMBASE, Web of Science, MEDLINE, and the Cochrane Library for studies published from the establishment of the databases to November 2020. Two researchers independently screened the identified studies, based on inclusion and exclusion criteria. The combined standard mean difference (SMD) and 95% confidence interval (CI) of data from the included studies were calculated using fixed- or random-effects models.

RESULTS

We included 10 studies in our meta-analysis (4 studies on T1DM and 6 on T2DM, with 239 participants) to examine the efficacy of mesenchymal stem cells (MSCs) therapy in the treatment of diabetes mellitus. According to the pooled estimates, the glycated hemoglobin (HbA1c) level of the MSC-treated group was significantly lower than it was at baseline (mean difference (MD) = -1.51, 95% CI -2.42 to -0.60, P = 0.001). The fasting C-peptide level of the MSC-treated group with T1DM was higher than that of the control group (SMD = 0.89, 95% CI 0.36 to 1.42, P = 0.001), and their insulin requirement was significantly lower than it was at baseline (SMD = -1.14, 95% CI -1.52 to -0.77, P < 0.00001).

CONCLUSION

Transplantation of mesenchymal stem cells has beneficial effects on diabetes mellitus, especially T1DM, and no obvious adverse reactions.

Mesenchymal Stem Cell-Based Therapy for Diabetes Mellitus: Enhancement Strategies and Future Perspectives

Diabetes mellitus (DM), a chronic disorder of carbohydrate metabolism, is characterized by the unbridled hyperglycemia resulted from the impaired ability of the body to either produce or respond to insulin. As a cell-based regenerative therapy, mesenchymal stem cells (MSCs) hold immense potency for curing DM duo to their easy isolation, multi-differentiation potential, and immunomodulatory property. However, despite the promising efficacy in pre-clinical animal models, naive MSC administration fails to exhibit clinically satisfactory therapeutic outcomes, which varies greatly among individuals with DM. Recently, numbers of innovative strategies have been applied to improve MSC-based therapy. Preconditioning, genetic modification, combination therapy and exosome application are representative strategies to maximize the therapeutic benefits of MSCs. Therefore, in this review, we summarize recent advancements in mechanistic studies of MSCs-based treatment for DM, and mainly focus on the novel approaches aiming to improve the anti-diabetic potentials of naive MSCs. Additionally, the potential directions of MSCs-based therapy for DM are also proposed at a glance.

Mesenchymal stromal cell-mediated immune regulation: A promising remedy in the therapy of type 2 diabetes mellitus

Type 2 diabetes mellitus (T2DM) is a major threat to global public health, with increasing prevalence as well as high morbidity and mortality, to which immune dysfunction has been recognized as a crucial contributor. Mesenchymal stromal cells (MSCs), obtained from various sources and possessing potent immunomodulatory abilities, have displayed great therapeutic potential for T2DM. Interestingly, the immunomodulatory capabilities of MSCs are endowed and plastic. Among the multiple mechanisms involved in MSC-mediated immune regulation, the paracrine effects of MSCs have attracted much attention. Of note, extracellular vesicles (EVs), an important component of MSC secretome, have emerged as pivotal mediators of their immunoregulatory effects. Particularly, the necrobiology of MSCs, especially apoptosis, has recently been revealed to affect their immunomodulatory functions in vivo. In specific, a variety of preclinical studies have demonstrated the beneficial effects of MSCs on improving islet function and ameliorating insulin resistance. More importantly, clinical trials have further uncovered the therapeutic potential of MSCs for T2DM. In this review, we outline current knowledge regarding the plasticity and underlying mechanisms of MSC-mediated immune modulation, focusing on the paracrine effects. We also summarize the applications of MSC-based therapies for T2DM in both preclinical studies and clinical trials, with particular emphasis on the modulation of immune system.

The Multi-Therapeutic Role of MSCs in Diabetic Nephropathy

Diabetic nephropathy (DN) is one of the most common diabetes mellitus (DM) microvascular complications, which always ends with end-stage renal disease (ESRD). Up to now, as the treatment of DN in clinic is still complicated, ESRD has become the main cause of death in diabetic patients. Mesenchymal stem cells (MSCs), with multi-differentiation potential and paracrine function, have attracted considerable attention in cell therapy recently. Increasing studies concerning the mechanisms and therapeutic effect of MSCs in DN emerged. This review summarizes several mechanisms of MSCs, especially MSCs derived exosomes in DN therapy, including hyperglycemia regulation, anti-inflammatory, anti-fibrosis, pro-angiogenesis, and renal function protection. We also emphasize the limitation of MSCs application in the clinic and the enhanced therapeutic role of pre-treated MSCs in the DN therapy. This review provides balanced and impartial views for MSC therapy as a promising strategy in diabetic kidney disease amelioration.

Mesenchymal Stem Cells: An Excellent Candidate for the Treatment of Diabetes Mellitus

Mesenchymal stem cells (MSCs) are adult stem cells (ASCs) known for repairing damaged cells, exerting anti-inflammatory responses and producing immunoregulatory effects that can be significantly induced into insulin-producing cells (IPCs), providing an inexhaustible supply of functional β cells for cell replacement therapy and disease modeling for diabetes. MSC therapy may be the most promising strategy for diabetes mellitus because of these significant merits. In this paper, we focused on MSC therapy for diabetes.

The investigation effect of weight loss on serum vaspin, apelin-13, and obestatin levels in obese individual

Objectives

It was aimed to investigate if there were any significant corresponding changes on adipokine levels in obese subjects who achieved a 10% reduction in body weight.

Methods

Thirty obese and 25 healthy adults were enrolled in present study, and serum levels of vaspin, apelin-13, obestatin, and insulin were determined with the ELISA method.

Results

The serum obestatin and apelin-13 values of the obese group obtained as basal and after weight loss was significantly lower than in controls (p<0.05, p<0.01, p<0.01, p<0.05, respectively); however, weight loss did not cause significant changes on these parameters in obese groups (p>0.05). The vaspin level did not differ between the groups (p>0.05). The obese group had characterized increased serum insulin and insulin resistance assessment by the homeostatic assay (HOMA-IR) levels compared to controls (p<0.01, p<0.05, respectively); also, weight loss caused a significant decrease in these parameters compared to basal levels (p<0.01). No significant correlation was detected among the vaspin, apelin-13 and obestatin levels in the obese group (p>0.05).

Conclusions

Obese individuals exhibited decreased levels of apelin-13 and obestatin. Moreover, 10% weight loss caused a significant reduction of insulin resistance, but no significant change was detected on apelin-13, obestatin, and vaspin levels.

Beneficial actions of a long-acting apelin analogue in diabetes are related to positive effects on islet cell turnover and transdifferentiation

AIM

The current study has tested the hypothesis that the positive effects of apelin receptor activation in diabetes are linked to benefits on islet cell apoptosis, proliferation and transdifferentiation using Ins1^Cre/+ ;Rosa26-eYFP transgenic mice and induction of diabetes-like syndromes by streptozotocin (STZ) or high-fat feeding.

MATERIALS AND METHODS

Groups (n = 6-8) of streptozotocin (STZ)-induced diabetic and high-fat diet (HFD)-fed mice received once-daily injection (25 nmol/kg) of the long-acting acylated apelin-13 analogue, pGlu(Lys⁸ Glu-PAL)apelin-13 amide, for 10 or 12 days, respectively.

RESULTS

pGlu(Lys⁸ Glu-PAL)apelin-13 amide treatment partly reversed body weight loss induced by STZ and normalized circulating insulin. There was no effect of pGlu(Lys⁸ Glu-PAL)apelin-13 amide on these variables in HFD-fed mice, but an increase in pancreatic insulin content was observed. pGlu(Lys⁸ Glu-PAL)apelin-13 amide also fully, or partially, reversed the detrimental effects of STZ and HFD on plasma and pancreatic glucagon concentrations. In HFD-fed mice, the apelin analogue decreased dietary-induced elevations of islet, β- and α-cell areas, whilst reducing α-cell area in STZ-induced diabetic mice. In terms of islet cell lineage, pGlu(Lys⁸ Glu-PAL)apelin-13 amide effectively reduced β- to α-cell transdifferentiation and helped maintain β-cell identity, which was linked to elevated Pdx-1 expression. These islet effects were coupled with decreased β-cell apoptosis and α-cell proliferation in both models, and there was an accompanying increase of β-cell proliferation in STZ-induced diabetic mice.

CONCLUSION

Taken together these data demonstrate, for the first time, that pancreatic islet benefits of sustained APJ receptor activation in diabetes are linked to favourable islet cell transition events, leading to maintenance of β-cell mass.

Myokines mediate the cross talk between skeletal muscle and other organs

Myokines are muscle-derived cytokines and chemokines that act extensively on organs and exert beneficial metabolic functions in the whole-body through specific signal networks. Myokines as mediators provide the conceptual basis for a whole new paradigm useful for understanding how skeletal muscle communicates with other organs. In this review, we summarize and discuss classes of myokines and their physiological functions in mediating the regulatory roles of skeletal muscle on other organs and the regulation of the whole-body energy metabolism. We review the mechanisms involved in the interaction between skeletal muscle and nonmuscle organs through myokines. Moreover, we clarify the connection between exercise, myokines and disease development, which may contribute to the understanding of a potential mechanism by which physical inactivity affects the process of metabolic diseases via myokines. Based on the current findings, myokines are important factors that mediate the effect of skeletal muscle on other organ functions and whole-body metabolism.

Mesenchymal Stem Cells: A Trump Card for the Treatment of Diabetes?

The advent of the new revolutionary approach based on regenerative medicine is progressively reshaping the therapeutic scenario of many different diseases, such as cardiovascular diseases and immune diseases, with encouraging results. During the last 10 years, many studies have also proposed the use of mesenchymal stem cells (MSCs), adult stem cells with several interesting properties already used in different experimental models, for the treatment of diabetes, however, reporting conflicting outcomes. These reasons have given rise to a question: are these cells a real trump card for the biomedical field? Are they really able to outclass the traditional therapies, or at least able to give an advantage over them? In this review, we will discuss the most promising results obtained with MSCs for the treatment of diabetes and its complications, we will compare the different therapeutic treatments applied as well as the most likely mechanisms of action, and overall we will give an in-depth overview of the pros and the cons of the use of MSCs for the therapy of both type-1 and type-2 diabetes.

Insight into adipokines to optimize therapeutic effects of stem cell for tissue regeneration

Stem cell therapy is considered as a promising regenerative medicine for repairing and treating damaged tissues and/or preventing various diseases. But there are still some obstacles such as low cell migration, poor stem cell engraftment and decreased cell survival that need to be overcome before transplantation. Therefore, a large body of studies has focused on improving the efficiency of stem cell therapy. For instance, preconditioning of stem cells has emerged as an effective strategy to reinforce therapeutic efficacy. Adipokines are signaling molecules, secreted by adipose tissue, which regulate a variety of biological processes in adipose tissue and other organs including the brain, liver, and muscle. In this review article, we shed light on the biological effects of some adipokines including apelin, oncostatin M, omentin-1 and vaspin on stem cell therapy and the most recent preclinical advances in our understanding of how these functions ameliorate stem cell therapy outcome.

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.

Apelin and stem cells: the role played in the cardiovascular system and energy metabolism

Apelin, a member of the adipokine family, is widely distributed in the body and exerts cytoprotective effects on many organs. Apelin isoforms are involved in different physiological processes, including regulation of the cardiovascular system, cardiac contractility, angiogenesis, and energy metabolism. Several investigations have been performed to study the effect of apelin on stem cell therapy. This review aims to summarize the literature representing the effects of apelin on stem cell properties. Furthermore, this review discusses the therapeutic potential of apelin-treated stem cells for cardiovascular diseases and demonstrates the effect of stem cells overexpressing apelin on energy metabolism. Stem cells with their unique characteristics play a crucial role in the maintenance of tissue integrity. These cells participate in tissue regeneration via multiple mechanisms. Although preclinical and clinical studies have demonstrated the therapeutic potential of stem cells in various diseases, their application in regenerative medicine has not been efficient. A number of strategies such as genetic modification or treatment of stem cells with different factors have been used to improve the efficacy of cell therapy and to increase their survival after transplantation. This article reviews the effect of apelin treatment on the efficacy of cell therapy.

Stem Cells in Equine Veterinary Practice-Current Trends, Risks, and Perspectives

With this Editorial, we introduce the Special Issue "Adipose-Derived Stem Cells and Their Extracellular Microvesicles (ExMVs) for Tissue Engineering and Regenerative Medicine Applications" to the scientific community. In this issue, we focus on regenerative medicine, stem cells, and their clinical application.