Mesenchymal Stem Cells Inhibit Generation and Function of Both CD34+-Derived and Monocyte-Derived Dendritic Cells

Exogenous MSC based tissue regeneration: a review of immuno-protection strategies from biomaterial scaffolds

Mesenchymal stem cell (MSC)-based tissue engineering holds great potential for regenerative medicine as a means of replacing damaged or lost tissues to restore their structure and function. However, the efficacy of MSC-based regeneration is frequently limited by the low survival rate and limited survival time of transplanted MSCs. Despite the inherent immune privileges of MSCs, such as low expression of major histocompatibility complex antigens, tolerogenic properties, local immunosuppressive microenvironment creation, and induction of immune tolerance, immune rejection remains a major obstacle to their survival and regenerative potential. Evidence suggests that immune protection strategies can enhance MSC therapeutic efficacy by prolonging their survival and maintaining their biological functions. Among various immune protection strategies, biomaterial-based scaffolds or cell encapsulation systems that mediate the interaction between transplanted MSCs and the host immune system or spatially isolate MSCs from the immune system for a specific time period have shown great promise. In this review, we provide a comprehensive overview of these biomaterial-based immune protection strategies employed for exogenous MSCs, highlighting the crucial role of modulating the immune microenvironment. Each strategy is critically examined, discussing its strengths, limitations, and potential applications in MSC-based tissue engineering. By elucidating the mechanisms behind immune rejection and exploring immune protection strategies, we aim to address the challenges faced by MSC-based tissue engineering and pave the way for enhancing the therapeutic outcomes of MSC therapies. The insights gained from this review will contribute to the development of more effective strategies to protect transplanted MSCs from immune rejection and enable their successful application in regenerative medicine.

Application of Mesenchymal Stem Cells in Female Infertility Treatment: Protocols and Preliminary Results

Infertility is a global phenomenon that impacts people of both the male and the female sex; it is related to multiple factors affecting an individual's overall systemic health. Recently, investigators have been using mesenchymal stem cell (MSC) therapy for female-fertility-related disorders such as polycystic ovarian syndrome (PCOS), premature ovarian failure (POF), endometriosis, preeclampsia, and Asherman syndrome (AS). Studies have shown promising results, indicating that MSCs can enhance ovarian function and restore fertility for affected individuals. Due to their regenerative effects and their participation in several paracrine pathways, MSCs can improve the fertility outcome. However, their beneficial effects are dependent on the methodologies and materials used from isolation to reimplantation. In this review, we provide an overview of the protocols and methods used in applications of MSCs. Moreover, we summarize the findings of published preclinical studies on infertility treatments and discuss the multiple properties of these studies, depending on the isolation source of the MSCs used.

Adipose-derived mesenchymal stem cell therapy for connective tissue diseases and complications

Mesenchymal stem cells (MSCs) may be effective in treating connective tissue disease and associated organ damage, leveraging their anti-inflammatory and immunoregulatory effects. Moreover, MSCs may possess the ability to produce antiapoptotic, proliferative, growth, angiogenic, and antifibrotic factors. Among MSCs, adipose-derived MSCs (ASCs) stand out for their relative ease of harvesting and abundance. Additionally, studies have indicated that compared with bone marrow-derived MSCs, ASCs have superior immunomodulatory, proangiogenic, antiapoptotic, and antioxidative properties. However, relatively few reviews have focused on the efficacy of ASC therapy in treating connective tissue disease (CTD) and interstitial lung disease (ILD). Therefore, this review aims to evaluate evidence from preclinical studies that investigate the effectiveness of MSC therapy, specifically ASC therapy, in managing CTD and ILD. Moreover, we explore the outcomes of documented clinical trials. We also introduce an innovative approach involving the utilization of pharmacologically primed ASCs in the CTD model to address the current challenges associated with ASC therapy.

A review of therapeutic approaches for post-infarction left ventricular remodeling

Left ventricular remodeling is an adaptive process initially developed in response to acute myocardial infarction (AMI), but it ends up with negative adverse outcomes such as infarcted wall thinning, ventricular dilation, and cardiac dysfunction. A prolonged excessive inflammatory reaction to cardiomyocytes death and necrosis plays the crucial role in the pathophysiological mechanisms. The pharmacological treatment includes nitroglycerine, β-blockers, ACEi/ARBs, SGLT2i, mineralocorticoid receptor antagonists, and some miscellaneous aspects. Stem cells therapy, CD34+ cells transplantation and gene therapy constitute the promissing therapeutic approaches for post AMI cardiac remodeling, thereby enhancing angiogenesis, cardiomyocytes differenciation and left ventricular function on top of inhibiting apoptosis, inflammation, and collagen deposition. All these lead to reduce infarct size, scar formation and myocardial fibrosis.

Therapeutic and Safety Promise of Mesenchymal Stem Cells for Liver Failure: From Preclinical Experiment to Clinical Application

Liver failure (LF) is serious liver damage caused by multiple factors, resulting in severe impairment or decompensation of liver synthesis, detoxification, metabolism, and biotransformation. The general prognosis of LF is poor with high mortality in non-transplant patients. The clinical treatments for LF are mainly internal medicine comprehensive care, artificial liver support system, and liver transplantation. However, none of the above treatment strategies can solve the problems of all liver failure patients and has its own limitations. Mesenchymal stem cells (MSCs) are a kind of stem cells with multidirectional differentiation potential and paracrine function, which play an important role in immune regulation and tissue regeneration. In recent years, MSCs have shown multiple advantages in the treatment of LF in pre-clinical experiments and clinical trials. In this work, we reviewed the biological characteristics of MSCs, the possible molecular mechanisms of MSCs in the treatment of liver failure, animal experiments, and clinical application, and also discussed the existing problems of MSCs in the treatment of liver failure.

The Multifunction Role of Tumor-Associated Mesenchymal Stem Cells and Their Interaction with Immune Cells in Breast Cancer

Mesenchymal stem cells (MSCs) are a heterogeneous group of progenitor cells that play a multifunctional role including tissue regeneration, self-renewal properties, and differentiate into cells of mesodermal lineage such as adipocytes, osteoblasts, and chondrocytes. MSCs come into contact with tumor microenvironment (TME) and differentiate into tumor-associated MSCs (TA-MSCs). Various substances such as chemokines, cytokines, growth factors, and others are released by tumor cells to recruit MSCs. TA-MSCs induced epithelial-mesenchymal transition (EMT) program which mediates tumor growth progression, migration, and invasion. Role of MSCs in the tumor progression, stemness, malignancy, and treatment resistance in the breast cancer TME. Immunomodulation by MSCs is mediated by a combination of cell contact-dependent mechanisms and soluble substances. Monocytes/macrophages, dendritic cells, T cells, B cells, and NK cells all show signs of MSCs' immunomodulatory capability. In a complicated interplay initiated by MSCs, anti-inflammatory monocytes/macrophages and regulatory T cells (Tregs) play a key role, as they unveil their full immunomodulatory potential. MSC- secreted cytokines are commonly blamed for the interaction between MSCs, monocytes, and Tregs. Here, we review the current knowledge of cellular and molecular mechanisms involved in MSC-mediated immunomodulation and focus on the role MSCs play in breast cancer progression and its TME.Abbreviation MSC: Mesenchymal Stem Cells; TME: Tumor Microenvironment; TAMS; Tumour-associated Macrophages; ECM: Extracellular matrix; CAFs: Cancer-associated Fibroblasts; CFUs: Colony-forming unit Fibroblasts; Tregs: T regulatory cells; Bregs; Regulatory B cells; IFN-γ: Interferon-gamma; TNF-α: Tumour Necrosis Factor-alpha; IL: Interleukin; TGF-β: transforming growth factorβ; PGE2: Prostaglandin E2; CXCR: Chemokine Receptor; Blimp-1; B lymphocyte-induced maturation protein-1; CCL: Chemokine motif ligand; EMT: Epithelial-mesenchymal transition.

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

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

Isolation, culture, and delivery considerations for the use of mesenchymal stem cells in potential therapies for acute liver failure

Acute liver failure (ALF) is a high-mortality syndrome for which liver transplantation is considered the only effective treatment option. A shortage of donor organs, high costs and surgical complications associated with immune rejection constrain the therapeutic effects of liver transplantation. Recently, mesenchymal stem cell (MSC) therapy was recognized as an alternative strategy for liver transplantation. Bone marrow mesenchymal stem cells (BMSCs) have been used in clinical trials of several liver diseases due to their ease of acquisition, strong proliferation ability, multipotent differentiation, homing to the lesion site, low immunogenicity and anti-inflammatory and antifibrotic effects. In this review, we comprehensively summarized the harvest and culture expansion strategies for BMSCs, the development of animal models of ALF of different aetiologies, the critical mechanisms of BMSC therapy for ALF and the challenge of clinical application.

Exploring the future potential of mesenchymal stem/stromal cells and their derivatives to support assisted reproductive technology for female infertility applications

Women's infertility impacts the quality of life of both patients and couples and has multifaceted dimensions that increase the number of challenges associated with female infertility and how to face them. Female reproductive disorders, such as premature ovarian failure (POF), endometriosis, Asherman syndrome (AS), polycystic ovary syndrome (PCOS), and preeclampsia, can stimulate infertility. In the last decade, translational medicine has advanced, and scientists are focusing on infertility therapy with innovative attitudes. Recent investigations have suggested that stem cell treatments could be safe and effective. Stem cell therapy has established a novel method for treating women's infertility as part of a regeneration approach. The chief properties and potential of mesenchymal stem/stromal cells (MSCs) in the future of women's infertility should be considered by researchers. Due to their high abundance, great ability to self-renew, and high differentiation capacity, as well as less ethical concerns, MSC-based therapy has been found to be an effective alternative strategy to the previous methods for treating female infertility, such as intrauterine insemination, in vitro fertilization, medicines, and surgical procedures. These types of stem cells exert their beneficial role by releasing active mediators, promoting cell homing, and contributing to immune modulation. Here we first provide an overview of MSCs and their crucial roles in both biological and immunological processes. The next large chapter covers current preclinical and clinical studies on the application of MSCs to treat various female reproductive disorders. Finally, we deliberate on the extant challenges that hinder the application of MSCs in female infertility and suggest plausible measures to alleviate these impediments.

The developing role of extracellular vesicles in autoimmune diseases: special attention to mesenchymal stem cell-derived extracellular vesicles

Autoimmune diseases are complex, chronic inflammatory conditions initiated by the loss of immunological tolerance to self-antigens. Nowadays, there is no effective and useful therapy for autoimmune diseases, and the existing medications have some limitations due to their nonspecific targets and side effects. During the last few decades, it has been established that mesenchymal stem cells (MSCs) have immunomodulatory functions. It is proposed that MSCs can exert an important therapeutic effect on autoimmune disorders. In parallel with these findings, several investigations have shown that MSCs alleviate autoimmune diseases. Intriguingly, the results of studies have demonstrated that the effective roles of MSCs in autoimmune diseases do not depend on direct intercellular communication but on their ability to release a wide spectrum of paracrine mediators such as growth factors, cytokines and extracellular vehicles (EVs). EVs that range from 50 to 5,000 nm were produced by almost any cell type, and these nanoparticles participate in homeostasis and intercellular communication via the transfer of a broad range of biomolecules such as modulatory proteins, nucleic acids (DNA and RNA), lipids, cytokines, and metabolites. EVs derived from MSCs display the exact properties of MSCs and can be safer and more beneficial than their parent cells. In this review, we will discuss the features of MSCs and their EVs, EVs biogenesis, and their cargos, and then we will highlight the existing discoveries on the impacts of EVs from MSCs on autoimmune diseases such as multiple sclerosis, arthritis rheumatic, inflammatory bowel disease, Type 1 diabetes mellitus, systemic lupus erythematosus, autoimmune liver diseases, Sjögren syndrome, and osteoarthritis, suggesting a potential alternative for autoimmune conditions therapy.

Mesenchymal Stromal Cells: Heterogeneity and Therapeutical Applications

Mesenchymal stromal cells nowadays emerge as a major player in the field of regenerative medicine and translational research. They constitute, with their derived products, the most frequently used cell type in different therapies. However, their heterogeneity, including different subpopulations, the anatomic source of isolation, and high donor-to-donor variability, constitutes a major controversial issue that affects their use in clinical applications. Furthermore, the intrinsic and extrinsic molecular mechanisms underlying their self-renewal and fate specification are still not completely elucidated. This review dissects the different heterogeneity aspects of the tissue source associated with a distinct developmental origin that need to be considered when generating homogenous products before their usage for clinical applications.

Contrariety of Human Bone Marrow Mesenchymal Stromal Cell Functionality in Modulating Circulatory Myeloid and Plasmacytoid Dendritic Cell Subsets

Mesenchymal Stromal Cells (MSCs) derived from bone marrow are widely tested in clinical trials as a cellular therapy for potential inflammatory disorders. The mechanism of action of MSCs in mediating immune modulation is of wide interest. In the present study, we investigated the effect of human bone-marrow-derived MSCs in modulating the circulating peripheral blood dendritic cell responses through flow cytometry and multiplex secretome technology upon their coculture ex vivo. Our results demonstrated that MSCs do not significantly modulate the responses of plasmacytoid dendritic cells. However, MSCs dose-dependently promote the maturation of myeloid dendritic cells. Mechanistic analysis showed that dendritic cell licensing cues (Lipopolysaccharide and Interferon-gamma) stimulate MSCs to secret an array of dendritic cell maturation-associated secretory factors. We also identified that MSC-mediated upregulation of myeloid dendritic cell maturation is associated with the unique predictive secretome signature. Overall, the present study demonstrated the dichotomy of MSC functionality in modulating myeloid and plasmacytoid dendritic cells. This study provides clues that clinical trials need to investigate if circulating dendritic cell subsets in MSC therapy can serve as potency biomarkers.

Research progress of engineered mesenchymal stem cells and their derived exosomes and their application in autoimmune/inflammatory diseases

Autoimmune/inflammatory diseases affect many people and are an important cause of global incidence and mortality. Mesenchymal stem cells (MSCs) have low immunogenicity, immune regulation, multidifferentiation and other biological characteristics, play an important role in tissue repair and immune regulation and are widely used in the research and treatment of autoimmune/inflammatory diseases. In addition, MSCs can secrete extracellular vesicles with lipid bilayer structures under resting or activated conditions, including exosomes, microparticles and apoptotic bodies. Among them, exosomes, as the most important component of extracellular vesicles, can function as parent MSCs. Although MSCs and their exosomes have the characteristics of immune regulation and homing, engineering these cells or vesicles through various technical means, such as genetic engineering, surface modification and tissue engineering, can further improve their homing and other congenital characteristics, make them specifically target specific tissues or organs, and improve their therapeutic effect. This article reviews the advanced technology of engineering MSCs or MSC-derived exosomes and its application in some autoimmune/inflammatory diseases by searching the literature published in recent years at home and abroad.

An overview of the current advances in the treatment of inflammatory diseases using mesenchymal stromal cell secretome

The growing interest in mesenchymal stromal cell (MSC) therapy has been leading to the utilization of its therapeutic properties in a variety of inflammatory diseases. The clinical translation of the related research from bench to bedside is cumbersome due to some obvious limitations of cell therapy. It is evident from the literature that the MSC secretome components mediate their wide range of functions. Cell-free therapy using MSC secretome is being considered as an emerging and promising area of biotherapeutics. The secretome mainly consists of bioactive factors, free nucleic acids, and extracellular vesicles. Constituents of the secretome are greatly influenced by the cell's microenvironment. The broad array of immunomodulatory properties of MSCs are now being employed to target inflammatory diseases. This review focuses on the emerging MSC secretome therapies for various inflammatory diseases. The mechanism of action of the various anti-inflammatory factors is discussed. The potential of MSC secretome as a viable anti-inflammatory therapy is deliberated.

Mesenchymal Stem Cells and Their Exocytotic Vesicles

Mesenchymal stem cells (MSCs), as a kind of pluripotent stem cells, have attracted much attention in orthopedic diseases, geriatric diseases, metabolic diseases, and sports functions due to their osteogenic potential, chondrogenic differentiation ability, and adipocyte differentiation. Anti-inflammation, anti-fibrosis, angiogenesis promotion, neurogenesis, immune regulation, and secreted growth factors, proteases, hormones, cytokines, and chemokines of MSCs have been widely studied in liver and kidney diseases, cardiovascular and cerebrovascular diseases. In recent years, many studies have shown that the extracellular vesicles of MSCs have similar functions to MSCs transplantation in all the above aspects. Here we review the research progress of MSCs and their exocrine vesicles in recent years.

Use of Mesenchymal Stem Cells in Crohn's Disease and Perianal Fistulas: A Narrative Review

Crohn's Disease (CD), which usually leads to anal fistulas among patients, is the most important inflammatory bowel disease that causes morbidity in many people around the world. This review article proposes using MSCs as a hopeful therapeutic strategy for CD and anal fistula treatment in both preclinical and clinical conditions. Finally, darvadstrocel, a cell-based medication to treat complex anal fistulas in adults, as the only European Medicines Agency (EMA)-approved product for the treatment of anal fistulas in CD is addressed. Although several common therapies, such as surgery and anti-tumor necrosis factor-alpha (TNF-α) drugs as well as a combination of these methods is used to improve this disease, however, due to the low effectiveness of these treatments, the use of new strategies with higher efficiency is still recommended. Cell therapy is among the new emerging therapeutic strategies that have attracted great attention from clinicians due to its unique capabilities. One of the most widely used cell sources administrated in cell therapy is mesenchymal stem cell (MSC). This review article will discuss preclinical and clinical studies about MSCs as a potent and promising therapeutic option in the treatment of CD and anal fistula.

MSCs can be a double-edged sword in tumorigenesis

Mesenchymal stem cells (MSCs) have been used to treat various diseases including Alzheimer's disease and cancer. In particular, the immunomodulatory function of MSCs plays a major role in cancer therapy using stem cells. However, MSCs exert promotive and inhibitory effects on cancer. The immunomodulatory effects of MSCs in the tumor microenvironment (TME) are ambiguous, which is the primary reason for the different outcomes of MSCs therapies for tumors. This review discusses the use of MSCs in cancer immunotherapy and their immunomodulatory mechanisms in cancers.

Osteoporosis treatment by mesenchymal stromal/stem cells and their exosomes: Emphasis on signaling pathways and mechanisms

Osteoporosis is the loss of bone density, which is one of the main problems in developed and developing countries and is more common in the elderly. Because this disease is often not diagnosed until a bone fracture, it can become a life-threatening disease and cause hospitalization. With the increase of older people in a population, this disease's personal and social costs increase year by year and affect different communities. Most current treatments focus on pain relief and usually do not lead to bone tissue recovery and regeneration. But today, the use of stem cell therapy is recommended to treat and improve this disease recovery, which helps restore bone tissue by improving the imbalance in the osteoblast-osteoclast axis. Due to mesenchymal stromal/stem cells (MSCs) characteristics and their exosomes, these cells and vesicles are excellent sources for treating and preventing the progression and improvement of osteoporosis. Due to the ability of MSCs to differentiate into different cells and migrate to the site of injury, these cells are used in tissue regenerative medicine. Also, due to their contents, the exosomes of these cells help regenerate and treat various tissue injuries by affecting the injury site's cells. In this article, we attempted to review new studies in which MSCs and their exosomes were used to treat osteoporosis.

Perivascular Mesenchymal Stem/Stromal Cells, an Immune Privileged Niche for Viruses?

Mesenchymal stem cells (MSCs) play a critical role in response to stress such as infection. They initiate the removal of cell debris, exert major immunoregulatory activities, control pathogens, and lead to a remodeling/scarring phase. Thus, host-derived ‘danger’ factors released from damaged/infected cells (called alarmins, e.g., HMGB1, ATP, DNA) as well as pathogen-associated molecular patterns (LPS, single strand RNA) can activate MSCs located in the parenchyma and around vessels to upregulate the expression of growth factors and chemoattractant molecules that influence immune cell recruitment and stem cell mobilization. MSC, in an ultimate contribution to tissue repair, may also directly trans- or de-differentiate into specific cellular phenotypes such as osteoblasts, chondrocytes, lipofibroblasts, myofibroblasts, Schwann cells, and they may somehow recapitulate their neural crest embryonic origin. Failure to terminate such repair processes induces pathological scarring, termed fibrosis, or vascular calcification. Interestingly, many viruses and particularly those associated to chronic infection and inflammation may hijack and polarize MSC’s immune regulatory activities. Several reports argue that MSC may constitute immune privileged sanctuaries for viruses and contributing to long-lasting effects posing infectious challenges, such as viruses rebounding in immunocompromised patients or following regenerative medicine therapies using MSC. We will herein review the capacity of several viruses not only to infect but also to polarize directly or indirectly the functions of MSC (immunoregulation, differentiation potential, and tissue repair) in clinical settings.

Possible Effect of the use of Mesenchymal Stromal Cells in the Treatment of Autism Spectrum Disorders: A Review

Autism spectrum disorder (ASD) represents a set of heterogeneous neurodevelopmental conditions defined by impaired social interactions and repetitive behaviors. The number of reported cases has increased over the past decades, and ASD is now a major public health burden. So far, only treatments to alleviate symptoms are available, with still unmet need for an effective disease treatment to reduce ASD core symptoms. Genetic predisposition alone can only explain a small fraction of the ASD cases. It has been reported that environmental factors interacting with specific inter-individual genetic background may induce immune dysfunctions and contribute to the incidence of ASD. Such dysfunctions can be observed at the central level, with increased microglial cells and activation in ASD brains or in the peripheral blood, as reflected by high circulating levels of pro-inflammatory cytokines, abnormal activation of T-cell subsets, presence of auto-antibodies and of dysregulated microbiota profiles. Altogether, the dysfunction of immune processes may result from immunogenetically-determined inefficient immune responses against a given challenge followed by chronic inflammation and autoimmunity. In this context, immunomodulatory therapies might offer a valid therapeutic option. Mesenchymal stromal cells (MSC) immunoregulatory and immunosuppressive properties constitute a strong rationale for their use to improve ASD clinical symptoms. In vitro studies and pre-clinical models have shown that MSC can induce synapse formation and enhance synaptic function with consequent improvement of ASD-like symptoms in mice. In addition, two preliminary human trials based on the infusion of cord blood-derived MSC showed the safety and tolerability of the procedure in children with ASD and reported promising clinical improvement of core symptoms. We review herein the immune dysfunctions associated with ASD provided, the rationale for using MSC to treat patients with ASD and summarize the current available studies addressing this subject.

Proteoglycan 4 is present within the dura mater and produced by mesenchymal progenitor cells

Mesenchymal progenitor cells (MPCs) have been recently identified in human and murine epidural fat and have been hypothesized to contribute to the maintenance/repair/regeneration of the dura mater. MPCs can secrete proteoglycan 4 (PRG4/lubricin), and this protein can regulate tissue homeostasis through bio-lubrication and immunomodulatory functions. MPC lineage tracing reporter mice (Hic1) and human epidural fat MPCs were used to determine if PRG4 is expressed by these cells in vivo. PRG4 expression co-localized with Hic1⁺ MPCs in the dura throughout skeletal maturity and was localized adjacent to sites of dural injury. When Hic1⁺ MPCs were ablated, PRG4 expression was retained in the dura, yet when Prx1⁺ MPCs were ablated, PRG4 expression was completely lost. A number of cellular processes were impacted in human epidural fat MPCs treated with rhPRG4, and human MPCs contributed to the formation of epidural fat, and dura tissues were xenotransplanted into mouse dural injuries. We have shown that human and mouse MPCs in the epidural/dura microenvironment produce PRG4 and can contribute to dura homeostasis/repair/regeneration. Overall, these results suggest that these MPCs have biological significance within the dural microenvironment and that the role of PRG4 needs to be further elucidated.

Mesenchymal Stem/Stromal Cells in Organ Transplantation

Organ transplantation is essential and crucial for saving and enhancing the lives of individuals suffering from end-stage organ failure. Major challenges in the medical field include the shortage of organ donors, high rates of organ rejection, and long wait times. To address the current limitations and shortcomings, cellular therapy approaches have been developed using mesenchymal stem/stromal cells (MSC). MSC have been isolated from various sources, have the ability to differentiate to important cell lineages, have anti-inflammatory and immunomodulatory properties, allow immunosuppressive drug minimization, and induce immune tolerance towards the transplanted organ. Additionally, rapid advances in the fields of tissue engineering and regenerative medicine have emerged that focus on either generating new organs and organ sources or maximizing the availability of existing organs. This review gives an overview of the various properties of MSC that have enabled its use as a cellular therapy for organ preservation and transplant. We also highlight emerging fields of tissue engineering and regenerative medicine along with their multiple sub-disciplines, underlining recent advances, widespread clinical applications, and potential impact on the future of tissue and organ transplantation.

Effect of Bone Marrow Mesenchymal Stromal Cell Therapies in Rodent Models of Sepsis: A Meta-Analysis

Background

Multiple preclinical studies have demonstrated that bone‐marrow derived mesenchymal stromal (stem) cells [MSC(M)] positively influence the severity of sepsis symptoms and mortality in rodent models. However, this remains an inconclusive finding.

Objective

To review the effect of naïve MSC(M) in rodent models of sepsis.

Methods

The PubMed, EMBASE, and Web of Science databases were searched up to August 31, 2021. Inclusion criteria according to PICOS criteria were as follows: (1) population: rodents; (2) intervention: unmodified MSC(M); (3) comparison: not specified; (4) primary outcome: the effects of MSC(M) cell therapy on the mortality of rodent models of sepsis and endotoxemia; (5) study: experimental studies. Multiple prespecified subgroup and meta-regression analysis were conducted. Following quality assessment, random effects models were used for this meta-analysis.The inverse variance method of the fixed effects model was used to calculate the pooled odds ratios (ORs) and their 95% confidence intervals (CIs).

Results

twenty-four animal studies met the inclusion criteria. Our results revealed an overall OR difference between animals treated with naïve MSC(M) and controls for mortality rate was 0.34(95% confidence interval: 0.27-0.44; P < 0.0001). Significant heterogeneity among studies was observed.

Conclusions

The findings of this meta-analysis suggest that naïve MSC(M) therapy decreased mortality in rodent models of sepsis. Additionally, we identified several key knowledge gaps, including the lack of large animal studies and uncertainty regarding the optimal dose of MSC(M) transplantation in sepsis. Before MSC(M) treatment can advance to clinical trials, these knowledge gaps must be addressed.

Mesenchymal Stem Cell-Immune Cell Interaction and Related Modulations for Bone Tissue Engineering

Critical bone defects and related delayed union and nonunion are still worldwide problems to be solved. Bone tissue engineering is mainly aimed at achieving satisfactory bone reconstruction. Mesenchymal stem cells (MSCs) are a kind of pluripotent stem cells that can differentiate into bone cells and can be used as one of the key pillars of bone tissue engineering. In recent decades, immune responses play an important role in bone regeneration. Innate immune responses provide a suitable inflammatory microenvironment for bone regeneration and initiate bone regeneration in the early stage of fracture repair. Adaptive immune responses maintain bone regeneration and bone remodeling. MSCs and immune cells regulate each other. All kinds of immune cells and secreted cytokines can regulate the migration, proliferation, and osteogenic differentiation of MSCs, which have a strong immunomodulatory ability to these immune cells. This review mainly introduces the interaction between MSCs and immune cells on bone regeneration and its potential mechanism, and discusses the practical application in bone tissue engineering by modulating this kind of cell-to-cell crosstalk. Thus, an in-depth understanding of these principles of bone immunology can provide a new way for bone tissue engineering.

OUP accepted manuscript

Bronchopulmonary dysplasia (BPD) is a life-threatening condition in preterm infants with few effective therapies. Mesenchymal stem or stromal cells (MSCs) are a promising therapeutic strategy for BPD. The ideal MSC source for BPD prevention is however unknown. The objective of this study was to compare the regenerative effects of MSC obtained from bone marrow (BM) and umbilical cord tissue (UCT) in an experimental BPD model. In vitro, UCT-MSC demonstrated greater proliferation and expression of anti-inflammatory cytokines as compared to BM-MSC. Lung epithelial cells incubated with UCT-MSC conditioned media (CM) had better-wound healing following scratch injury. UCT-MSC CM and BM-MSC CM had similar pro-angiogenic effects on hyperoxia-exposed pulmonary microvascular endothelial cells. In vivo, newborn rats exposed to normoxia or hyperoxia (85% O₂) from postnatal day (P) 1 to 21 were given intra-tracheal (IT) BM or UCT-MSC (1 × 10⁶ cells/50 μL), or placebo (PL) on P3. Hyperoxia PL-treated rats had marked alveolar simplification, reduced lung vascular density, pulmonary vascular remodeling, and lung inflammation. In contrast, administration of both BM-MSC and UCT-MSC significantly improved alveolar structure, lung angiogenesis, pulmonary vascular remodeling, and lung inflammation. UCT-MSC hyperoxia-exposed rats however had greater improvement in some morphometric measures of alveolarization and less lung macrophage infiltration as compared to the BM-MSC-treated group. Together, these findings suggest that BM-MSC and UCT-MSC have significant lung regenerative effects in experimental BPD but UCT-MSC suppresses lung macrophage infiltration and promotes lung epithelial cell healing to a greater degree.

Changes of Migration, Immunoregulation and Osteogenic Differentiation of Mesenchymal Stem Cells in Different Stages of Inflammation

Bone infection has always been the focus of orthopedic research. Mesenchymal stem cells (MSCs) are the natural progenitors of osteoblasts, and the process of osteogenesis is triggered in response to different signals from the extracellular matrix. MSCs exert important functions including secretion and immune regulation and also play a key role in bone regeneration. The biological behavior of MSCs in acute and chronic inflammation, especially the transformation between acute inflammation and chronic inflammation, has aroused great interest among researchers. This paper reviews the recent literature and summarizes the behavior and biological characteristics of MSCs in acute and chronic inflammation to stimulate further research on MSCs and treatment of bone diseases.

Xenogeneic Humoral Immune Responses to Human Mesenchymal Stem Cells in Mice

Background and Objectives

Many preclinical studies have been conducted using animal disease models to determine the effectiveness of human mesenchymal stem cells (hMSCs) for treating immune and inflammatory diseases based on the belief that hMSCs are not immunogenic across species. However, several researchers have suggested xenogeneic immune responses to hMSCs in animals, still without detailed features. This study aimed to investigate a xenogeneic humoral immune response to hMSCs in mice in detail.

Methods and Results

Balb/c mice were intraperitoneally injected with adipose tissue-derived or Wharton’s jelly-derived hMSCs. Sera from these mice were titrated for each isotype. To confirm specificity of the antibodies, hMSCs were stained with the sera and subjected to a flow cytometic analysis. Spleens were immunostained for proliferating cell nuclear antigen to verify the germinal center formation. Additionally, splenocytes were subjected to a flow cytometric analysis for surface markers including GL-7, B220, CD4, CD8, CD44, and CD62L. Similar experiments were repeated in C57BL/6 mice. The results showed increased IgG₁ and IgG_2a titers in the sera from Balb/c mice injected with hMSCs, and the titers were much higher in the secondary sera than in the primary sera. These antibodies were specifically stained the hMSCs. Germinal centers were observed in the spleen, and flow cytometric analysis of the splenocytes showed higher frequencies of centroblasts (B220^＋ GL7^＋) and memory T cells (CD62L^＋ CD44^＋) both in CD4^＋ and CD8^＋ subsets. Similar results were obtained for C57BL/6 mice.

Conclusions

hMSCs induced a humoral immune response in mice, with characters of T cell-dependent immunity.

Proteomic Analysis of Mesenchymal Stromal Cell-Derived Extracellular Vesicles and Reconstructed Membrane Particles

Extracellular vesicles (EV) derived from mesenchymal stromal cells (MSC) are a potential therapy for immunological and degenerative diseases. However, large-scale production of EV free from contamination by soluble proteins is a major challenge. The generation of particles from isolated membranes of MSC, membrane particles (MP), may be an alternative to EV. In the present study we generated MP from the membranes of lysed MSC after removal of the nuclei. The yield of MP per MSC was 1 × 10⁵ times higher than EV derived from the same number of MSC. To compare the proteome of MP and EV, proteomic analysis of MP and EV was performed. MP contained over 20 times more proteins than EV. The proteins present in MP evidenced a multi-organelle origin of MP. The projected function of the proteins in EV and MP was very different. Whilst proteins in EV mainly play a role in extracellular matrix organization, proteins in MP were interconnected in diverse molecular pathways, including protein synthesis and degradation pathways and demonstrated enzymatic activity. Treatment of MSC with IFNγ led to a profound effect on the protein make up of EV and MP, demonstrating the possibility to modify the phenotype of EV and MP through modification of parent MSC. These results demonstrate that MP are an attractive alternative to EV for the development of potential therapies. Functional studies will have to demonstrate therapeutic efficacy of MP in preclinical disease models.

Immune response to allogeneic equine mesenchymal stromal cells

BACKGROUND

Mesenchymal stromal cells (MSCs) are believed to be hypoimmunogeneic with potential use for allogeneic administration.

METHODS

Bone marrow was harvested from Connemara (n = 1), Standardbred (n = 6), and Thoroughbred (n = 3) horses. MSCs were grouped by their level of expression of major histocompatibility factor II (MHC II). MSCs were then sub-grouped by those MSCs derived from universal blood donor horses. MSCs were isolated and cultured using media containing fetal bovine serum until adequate numbers were acquired. The MSCs were cultured in xenogen-free media for 48 h prior to use and during all assays. Autologous and allogeneic MSCs were then directly co-cultured with responder leukocytes from the Connemara horse in varying concentrations of MSCs to leukocytes (1:1, 1:10, and 1:100). MSCs were also cultured with complement present and heat-inactivated complement to determine whether complement alone would decrease MSC viability. MSCs underwent haplotyping of their equine leukocyte antigen (ELA) to determine whether the MHC factors were matched or mismatched between the donor MSCs and the responder leukocytes.

RESULTS

All allogeneic MSCs were found to be ELA mismatched with the responder leukocytes. MHC II-low and universal blood donor MSCs caused no peripheral blood mononuclear cell (PBMC) proliferation, no increase in B cells, and no activation of CD8 lymphocytes. Universal blood donor MSCs stimulated a significant increase in the number of T regulatory cells. Neutrophil interaction with MSCs showed that universal blood donor and MHC II-high allogeneic MSCs at the 6 h time point in co-culture caused greater neutrophil activation than the other co-culture groups. Complement-mediated cytotoxicity did not consistently cause MSC death in cultures with active complement as compared to those with inactivated complement. Gene expression assays revealed that the universal blood donor group and the MHC II-low MSCs were more metabolically active both in the anabolic and catabolic gene categories when cultured with allogeneic lymphocytes as compared to the other co-cultures. These upregulated genes included CD59, FGF-2, HGF, IDO, IL-10, IL-RA, IL-2, SOX2, TGF-β1, ADAMSTS-4, ADAMSTS-5, CCL2, CXCLB/IL-8, IFNγ, IL-1β, and TNFα.

CONCLUSIONS

MHC II-low MSCs are the most appropriate type of allogeneic MSC to prevent activation of the innate and cell-mediated component of the adaptive immune systems and have increased gene expression as compared to other allogeneic MSCs.

Phenotypic and Functional Responses of Human Decidua Basalis Mesenchymal Stem/Stromal Cells to Lipopolysaccharide of Gram-Negative Bacteria

Introduction

Human decidua basalis mesenchymal stem cells (DBMSCs) are potential therapeutics for the medication to cure inflammatory diseases, like atherosclerosis. The current study investigates the capacity of DBMSCs to stay alive and function in a harmful inflammatory environment induced by high levels of lipopolysaccharide (LPS).

Methods

DBMSCs were exposed to different levels of LPS, and their viability and functional responses (proliferation, adhesion, and migration) were examined. Furthermore, DBMSCs’ expression of 84 genes associated with their functional activities in the presence of LPS was investigated.

Results

Results indicated that LPS had no significant effect on DBMSCs’ adhesion, migration, and proliferation (24 h and 72 h) (p > 0.05). However, DBMSCs’ proliferation was significantly reduced at 10 µg/mL of LPS at 48 h (p < 0.05). In addition, inflammatory cytokines and receptors related to adhesion, proliferation, migration, and differentiation were significantly overexpressed when DBMSCs were treated with 10 µg/mL of LPS (p < 0.05).

Conclusion

These results indicated that DBMSCs maintained their functional activities (proliferation, adhesion, and migration) in the presence of LPS as there was no variation between the treated DBMSCs and the control group. This study will lay the foundation for future preclinical and clinical studies to confirm the appropriateness of DBMSCs as a potential medication to cure inflammatory diseases, like atherosclerosis.

The Role of Cell Organelles in Rheumatoid Arthritis with Focus on Exosomes

Auto-immune diseases involved at least 25% of the population in wealthy countries. Several factors including genetic, epigenetic, and environmental elements are implicated in development of Rheumatoid Arthritis as an autoimmune disease. Autoantibodies cause synovial inflammation and arthritis, if left untreated or being under continual external stimulation, could result in chronic inflammation, joint injury, and disability. T- and B-cells, signaling molecules, proinflammatory mediators, and synovium-specific targets are among the new therapeutic targets. Exosomes could be employed as therapeutic vectors in the treatment of autoimmune diseases. Herein, the role of cell organelle particularly exosomes in Rheumatoid Arthritis had discussed and some therapeutic applications of exosome highlighted.

Dissecting the relationship between antimicrobial peptides and mesenchymal stem cells

Among the various biological properties presented by Mesenchymal Stem Cells (MSCs), their ability to control the immune response and fight pathogen infection through the production of antimicrobial peptides (AMPs) have been the subject of intense research in recent years. AMPs secreted by MSCs exhibit activity against a wide range of microorganisms, including bacteria, fungi, yeasts, and viruses. The main AMPs produced by these cells are hepcidin, cathelicidin LL-37, and β-defensin-2. In addition to acting against pathogens, those AMPs have also been shown to interact with MSCs to modulate MSC proliferation, migration, and regeneration, indicating that such peptides exert a more diverse biological effect than initially thought. In the present review, we discuss the production of AMPs by MSCs, revise the multiple functions of these peptides, including their influence over MSCs, and present an overview of clinical situations in which the antimicrobial properties of MSCs may be explored for therapy. Finally, we discuss possibilities of combining MSCs and AMPs to generate improved therapeutic strategies.

Mesenchymal Stem Cells in the Treatment of COVID-19, a Promising Future

Mesenchymal stem cells (MSCs) are multipotent adult stem cells present in virtually all tissues; they have a potent self-renewal capacity and can differentiate into multiple cell types. They also affect the ambient tissue by the paracrine secretion of numerous factors in vivo, including the induction of other stem cells’ differentiation. In vitro, the culture media supernatant is named secretome and contains soluble molecules and extracellular vesicles that retain potent biological function in tissue regeneration. MSCs are considered safe for human treatment; their use does not involve ethical issues, as embryonic stem cells do not require genetic manipulation as induced pluripotent stem cells, and after intravenous injection, they are mainly found in the lugs. Therefore, these cells are currently being tested in various preclinical and clinical trials for several diseases, including COVID-19. Several affected COVID-19 patients develop induced acute respiratory distress syndrome (ARDS) associated with an uncontrolled inflammatory response. This condition causes extensive damage to the lungs and may leave serious post-COVID-19 sequelae. As the disease may cause systemic alterations, such as thromboembolism and compromised renal and cardiac function, the intravenous injection of MSCs may be a therapeutic alternative against multiple pathological manifestations. In this work, we reviewed the literature about MSCs biology, focusing on their function in pulmonary regeneration and their use in COVID-19 treatment.

Mesenchymal Stromal Cells Isolated from Ectopic but Not Eutopic Endometrium Display Pronounced Immunomodulatory Activity In Vitro

A comparative analysis of the cell surface markers and immunological properties of cell cultures originating from normal endometrium and endometrioid heterotopias of women with extragenital endometriosis was carried out. Both types of cell cultures expressed surface molecules typical of mesenchymal stromal cells and did not express hematopoietic and epithelial markers. Despite similar phenotype, the mesenchymal stromal cells derived from the two sources had different immunomodulation capacities: the cells of endometrioid heterotopias but not eutopic endometrium could suppress dendritic cell differentiation from monocytes as well as lymphocyte proliferation in allogeneic co-cultures. A comparative multiplex analysis of the secretomes revealed a significant increase in the secretion of pro-inflammatory mediators, including IL6, IFN-γ, and several chemokines associated with inflammation by the stromal cells of ectopic lesions. The results demonstrate that the stromal cells of endometrioid heterotopias display enhanced pro-inflammatory and immunosuppressive activities, which most likely impact the pathogenesis and progression of the disease.

Human Fallopian Tube - Derived Mesenchymal Stem Cells Inhibit Experimental Autoimmune Encephalomyelitis by Suppressing Th1/Th17 Activation and Migration to Central Nervous System

Mesenchymal stem cells comprise a natural reservoir of undifferentiated cells within adult tissues. Given their self-renewal, multipotency, regenerative potential and immunomodulatory properties, MSCs have been reported as a promising cell therapy for the treatment of different diseases, including neurodegenerative and autoimmune diseases. In this study, we investigated the immunomodulatory properties of human tubal mesenchymal stem cells (htMSCs) using the EAE model. htMSCs were able to suppress dendritic cells activation downregulating antigen presentation-related molecules, such as MHCII, CD80 and CD86, while impairing IFN-γ and IL-17 and increasing IL-10 and IL-4 secretion. It further correlated with milder disease scores when compared to the control group due to fewer leukocytes infiltrating the CNS, specially Th1 and Th17 lymphocytes, associated with increased IL-10 secreting Tr1 cells. Conversely, microglia were less activated and infiltrating mononuclear cells secreted higher levels of IL-4 and IL-10 and expressed reduced chemokine receptors as CCR4, CCR6 and CCR8. qPCR of the spinal cords revealed upregulation of indoleamine-2,3-dioxygenase (IDO) and brain derived neurotrophic factor (BDNF). Taken together, here evidenced the potential of htMSCs as an alternative for the treatment of inflammatory, autoimmune or neurodegenerative diseases.

Immunomodulation effect of mesenchymal stem cells in islet transplantation

Mesenchymal stem cells (MSCs) therapy has brought a great enthusiasm to the treatment of various immune disorders, tissue regeneration and transplantation therapy. MSCs are being extensively investigated for their immunomodulatory actions. MSCs can deliver immunomodulatory signals to inhibit allogeneic T cell immune responses by downregulating pro-inflammatory cytokines and increasing regulatory cytokines and growth factors. Islet transplantation is a therapeutic alternative to the insulin therapy for the treatment of type 1 diabetes mellitus (T1DM). However, the acute loss of islets due to the lack of vasculature and hypoxic milieu in the immediate post-transplantation period may lead to treatment failure. Moreover, despite the use of potent immunosuppressive drugs, graft failure persists because of immunological rejection. Many in vitro and in vivo researches have demonstrated the multipotency of MSCs as a mediator of immunomodulation and a great approach for enhancement of islet engraftment. MSCs can interact with immune cells of the innate and adaptive immune systems via direct cell-cell contact or through secretomes containing numerous soluble growth and immunomodulatory factors or mitochondrial transfer. This review highlights the interactions between MSCs and different immune cells to mediate immunomodulatory functions along with the importance of MSCs therapy for the successful islet transplantation.

Effects of Administration Route of Adipose-Derived Stem Cells on the Survival of Allogeneic Skin Grafts in Mice

BACKGROUND

Composite tissue allotransplantation presents considerable potential for defective tissue reconstruction. However, the high immunogenicity of the allogeneic skin grafts can cause acute rejection. Adipose-derived stem cells (ADSCs) reportedly have an immunomodulation potential, which may improve the survival of allogeneic skin grafts. However, there is currently no consensus on administration route of ADSCs. This study compared the effectiveness of local injection vs intravenous (IV) administration of ADSCs in improving the survival of allogenic skin grafts in mice.

METHODS

BALB/c and C57BL/6 mice were used as skin graft donors and recipients, respectively. Mice were divided into 3 groups for IV injection of ADSCs (IV group) or phosphate-buffered saline (PBS; control), or for local injection in the fascial layer of the recipient bed (FL group). After allogeneic skin transplantation, 0.1 mL of PBS alone or with 1.5 × 10⁵ ADSCs was immediately injected. The grafts were histologically evaluated on days 7 and 14 postoperation.

RESULTS

The graft necrotic area was significantly smaller in the IV and FL groups than in the control group. Additionally, the grafts in these 2 groups exhibited decreased interleukin 17/6, tumor necrosis factor-α, and interferon-γ messenger mRNA levels; inflammatory changes; and cluster of differentiation 4 expression, and increased expression of vascular endothelial growth factor expression (P < .05). However, these 2 groups did not significantly differ (P > .05).

CONCLUSIONS

ADSCs increased the survival of allogeneic skin grafts in mice regardless of IV or FL route of administration, and this effect is likely through anti-inflammatory and angiogenic effects of ADSCs.

Therapeutic potential of human umbilical cord mesenchymal stem cells on aortic atherosclerotic plaque in a high-fat diet rabbit model

BACKGROUND

Atherosclerosis (AS) is a complex disease caused in part by dyslipidemia and chronic inflammation. AS is associated with serious cardiovascular disease and remains the leading cause of mortality worldwide. Mesenchymal stem cells (MSCs) have evolved as an attractive therapeutic agent in various diseases including AS. Human umbilical cord MSCs (UCSCs) have been used in cell therapy trials due to their ability to differentiate and proliferate. The present study aimed to investigate the effect of UCSCs treatment on atherosclerotic plaque formation and the progression of lesions in a high-fat diet rabbit model.

METHODS

Rabbits were fed a high-fat diet and then randomly divided into three groups: control, model, and treatment groups. Rabbits in the treatment group were injected with UCSCs (6 × 106 in 500 μL phosphate buffered saline) after 1 month of high-fat diet, once every 2 weeks, for 3 months. The model group was given PBS only. We analyzed serum biomarkers, used ultrasound and histopathology to detect arterial plaques and laser Doppler imaging to measure peripheral blood vessel blood filling, and analyzed the intestinal flora and metabolism.

RESULTS

Histological analysis showed that the aortic plaque area was significantly reduced in the treatment group. We also found a significant decrease in macrophage accumulation and apoptosis, an increase in expression of scavenger receptors CD36 and SRA1, a decrease in uptake of modified low-density protein (ox-LDL), and a decrease in levels of pro-inflammatory cytokines interleukin (IL)-6 and tumor necrosis factor (TNF)-α following UCSCs treatment. We also found that anti-inflammatory cytokines IL-10 and transforming growth factor (TGF)-β expression increased in the aorta atherosclerotic plaque of the treatment group. UCSCs treatment improved the early peripheral blood filling, reduced the serum lipid level, and inhibited inflammation progression by regulating the intestinal flora dysbiosis caused by the high-fat diet. More specifically, levels of the microbiota-dependent metabolite trimethylamine-N-oxide (TMAO) were down-regulated in the treatment group.

CONCLUSIONS

UCSCs treatment alleviated atherosclerotic plaque burden by reducing inflammation, regulating the intestinal flora and TMAO levels, and repairing the damaged endothelium.

From Mesenchymal Stromal/Stem Cells to Insulin-Producing Cells: Immunological Considerations

Mesenchymal stem cell (MSC)-based therapy for type 1 diabetes mellitus (T1DM) has been the subject matter of many studies over the past few decades. The wide availability, negligible teratogenic risks and differentiation potential of MSCs promise a therapeutic alternative to traditional exogenous insulin injections or pancreatic transplantation. However, conflicting arguments have been reported regarding the immunological profile of MSCs. While some studies support their immune-privileged, immunomodulatory status and successful use in the treatment of several immune-mediated diseases, others maintain that allogeneic MSCs trigger immune responses, especially following differentiation or in vivo transplantation. In this review, the intricate mechanisms by which MSCs exert their immunomodulatory functions and the influencing variables are critically addressed. Furthermore, proposed avenues to enhance these effects, including cytokine pretreatment, coadministration of mTOR inhibitors, the use of Tregs and gene manipulation, are presented. As an alternative, the selection of high-benefit, low-risk donors based on HLA matching, PD-L₁ expression and the absence of donor-specific antibodies (DSAs) are also discussed. Finally, the necessity for the transplantation of human MSC (hMSC)-derived insulin-producing cells (IPCs) into humanized mice is highlighted since this strategy may provide further insights into future clinical applications.

Activation of aryl hydrocarbon receptor (AhR) in mesenchymal stem cells modulates macrophage polarization in asthma

Macrophage polarization has been demonstrated to exert a vital role on asthma pathogenesis. Mesenchymal stem cells (MSC) have the capacity to modulate macrophage differentiation from a pro-inflammatory M1 phenotype toward an anti-inflammatory M2 phenotype. However, the impact of MSC-macrophage interactions on asthma development and underlying mechanisms responsible for this interaction remain largely unknown. The aim of this study was to investigate the role of AhR expressed on MSC in macrophage polarization in a cockroach extract (CRE)-induced asthma mouse model. The studies here revealed that MSC polarized macrophages from a pro-inflammatory M1 phenotype toward an anti-inflammatory M2 phenotype in this model. The mRNA levels of interleukin (IL)-6, IL-1β, and NOS2 as M1 markers were significantly decreased while those of select M2 markers such as Arg-1, FIZZ1, and YM-1 were significantly enhanced. It was also observed that aryl hydrocarbon receptor (AhR) signaling was significantly increased during asthma pathogenesis as demonstrated by enhanced mRNA expression of AhR, CYP1a1, and CYP1b1. It was also seen that the elevated AhR signaling was able to attenuate the onset of asthma. Use of an AhR antagonist (CH223191) resulted in significant inhibition of the AhR signaling and increases in M2 marker expression, but led to elevation of expression of M1 markers in the CRE-induced asthma model. Taken together, the current study showed that MSC can modulate macrophage polarization, in part, via activation of AhR signaling during CRE-induced asthma.

Human mesenchymal stem cells inhibit the differentiation and effector functions of monocytes

Although monocytes represent an essential part of the host defence system, their accumulation and prolonged stimulation could be detrimental and may aggravate chronic inflammatory diseases. The present study has explored the less-understood immunomodulatory effects of mesenchymal stem cells on monocyte functions. Isolated purified human monocytes were co-cultured with human umbilical cord-derived mesenchymal stem cells under appropriate culture conditions to assess monocytes' vital functions. Based on the surface marker analysis, mesenchymal stem cells halted monocyte differentiation into dendritic cells and macrophages and reduced their phagocytosis functions, which rendered an inability to stimulate T-cell proliferation. The present study confers that mesenchymal stem cells exerted potent immunosuppressive activity on monocyte functions such as differentiation, phagocytosis and Ag presentation; hence, they promise a potential therapeutic role in down-regulating the unwanted monocyte-mediated immune responses in the context of chronic inflammatory diseases.

Mesenchymal stromal cell-derived exosomes in cardiac regeneration and repair

Mesenchymal stromal cell (MSC)-derived exosomes play a promising role in regenerative medicine. Their trophic and immunomodulatory potential has made them a promising candidate for cardiac regeneration and repair. Numerous studies have demonstrated that MSC-derived exosomes can replicate the anti-inflammatory, anti-apoptotic, and pro-angiogenic and anti-fibrotic effects of their parent cells and are considered a substitute for cell-based therapies. In addition, their lower tumorigenic risk, superior immune tolerance, and superior stability compared with their parent stem cells make them an attractive option in regenerative medicine. The therapeutic effects of MSC-derived exosomes have consequently been evaluated for application in cardiac regeneration and repair. In this review, we summarize the potential mechanisms and therapeutic effects of MSC-derived exosomes in cardiac regeneration and repair and provide evidence to support their clinical application.

Immunomodulatory Effects of Mesenchymal Stem Cells on Drug-Induced Acute Kidney Injury

Drug-induced nephrotoxicity is an important and increasing cause of acute kidney injury (AKI), which accounts for approximately 20% of hospitalized patients. Previous reviews studies on immunity and AKI focused mainly on ischemia-reperfusion (IR), whereas no systematic review addressing drug-induced AKI and its related immune mechanisms is available. Recent studies have provided a deeper understanding on the mechanisms of drug-induced AKI, among which acute tubular interstitial injury induced by the breakdown of innate immunity was reported to play an important role. Emerging research on mesenchymal stem cell (MSC) therapy has revealed its potential as treatment for drug-induced AKI. MSCs can inhibit kidney damage by regulating the innate immune balance, promoting kidney repair, and preventing kidney fibrosis. However, it is important to note that there are various sources of MSCs, which impacts on the immunomodulatory ability of the cells. This review aims to address the immune pathogenesis of drug-induced AKI versus that of IR-induced AKI, and to explore the immunomodulatory effects and therapeutic potential of MSCs for drug-induced AKI.

Recent Trends in Multipotent Human Mesenchymal Stem/Stromal Cells: Learning from History and Advancing Clinical Applications

Early cell biology reports demonstrated the presence of cells with stem-like properties in bone marrow, with both hematopoietic and mesenchymal lineages. Over the years, various investigations have purified and characterized mesenchymal stromal/stem cells (MSCs) from different human tissues as cells with multilineage differentiation potential under the appropriate conditions. Due to their appealing characteristics and versatile potentials, MSCs are leveraged in many applications in medicine such as oncology, bioprinting, and as recent as therapeutics discovery and innovation for COVID-19. To date, studies indicate that MSCs have varied differentiation capabilities into different cell types, and demonstrate immunomodulating and anti-inflammatory properties. Different microenvironments or niche for MSCs and their resulting heterogeneity may influence attendant cellular behavior and differentiation capacity. The potential clinical applications of MSCs and exosomes derived from these cells have led to an avalanche of research reports on their properties and hundreds of clinical trials being undertaken. There is ample reason to think, as discussed in this expert review that the future looks bright and promising for MSC research, with many clinical trials under way to ascertain their clinical utility. This review provides a synthesis of the latest advances and trends in MSC research to allow for broad and critically informed use of MSCs. Early observations of the presence of these cells in the bone marrow and their remarkable differentiation capabilities and immunomodulation are also presented.

Mesenchymal Stromal Cells and Their Secretome: New Therapeutic Perspectives for Skeletal Muscle Regeneration

Mesenchymal stromal cells (MSCs) are multipotent cells found in different tissues: bone marrow, peripheral blood, adipose tissues, skeletal muscle, perinatal tissues, and dental pulp. MSCs are able to self-renew and to differentiate into multiple lineages, and they have been extensively used for cell therapy mostly owing to their anti-fibrotic and immunoregulatory properties that have been suggested to be at the basis for their regenerative capability. MSCs exert their effects by releasing a variety of biologically active molecules such as growth factors, chemokines, and cytokines, either as soluble proteins or enclosed in extracellular vesicles (EVs). Analyses of MSC-derived secretome and in particular studies on EVs are attracting great attention from a medical point of view due to their ability to mimic all the therapeutic effects produced by the MSCs (i.e., endogenous tissue repair and regulation of the immune system). MSC-EVs could be advantageous compared with the parental cells because of their specific cargo containing mRNAs, miRNAs, and proteins that can be biologically transferred to recipient cells. MSC-EV storage, transfer, and production are easier; and their administration is also safer than MSC therapy. The skeletal muscle is a very adaptive tissue, but its regenerative potential is altered during acute and chronic conditions. Recent works demonstrate that both MSCs and their secretome are able to help myofiber regeneration enhancing myogenesis and, interestingly, can be manipulated as a novel strategy for therapeutic interventions in muscular diseases like muscular dystrophies or atrophy. In particular, MSC-EVs represent promising candidates for cell free-based muscle regeneration. In this review, we aim to give a complete picture of the therapeutic properties and advantages of MSCs and their products (MSC-derived EVs and secreted factors) relevant for skeletal muscle regeneration in main muscular diseases.

[Clinical research progress of mesenchymal stem cells in treatment of chronic wounds]

Objective

To review the clinical research progress of mesenchymal stem cells (MSCs) in the treatment of chronic wounds.

Methods

The literature related to the chronic wound repair with MSCs at home and abroad in recent years was extensively reviewed, and the possible mechanism of MSCs in the treatment of chronic wounds, as well as its application and existing problems were summarized.

Results

MSCs can participate in all aspects of chronic wound healing to promote wound healing, and has shown broad application prospects in clinical trials. MSCs commonly used in clinical research include bone marrow-derived MSCs, adipose-derived tissue MSCs, and umbilical cord-derived MSCs.

Conclusion

MSCs treatment is a promising strategy for the chronic wounds, but there are still many problems in its widespread clinical application that require further research.

Taming of Covid-19: potential and emerging application of mesenchymal stem cells

Coronavirus Disease 2019 (COVID-19) caused by the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) has turned out to cause a pandemic, with a sky scraping mortality. The virus is thought to cause tissue injury by affecting the renin-angiotensin system. Also, the role of the over-activated immune system is noteworthy, leading to severe tissue injury via the cytokine storms. Thus it would be feasible to modulate the immune system response in order to attenuate the disease severity, as well as treating the patients. Today different medicines are being administered to the patients, but regardless of the efficacy of these treatments, adverse effects are pretty probable. Meanwhile, mesenchymal stem cells (MSCs) prove to be an effective candidate for treating the patients suffering from COVID-19 pneumonia, owing to their immunomodulatory and tissue-regenerative potentials. So far, several experiments have been conducted; transplanting MSCs and results are satisfying with no adverse effects being reported. This paper aims to review the recent findings regarding the novel coronavirus and the conducted experiments to treat patients suffering from COVID-19 pneumonia utilizing MSCs.

Mesenchymal Stromal Cells in Viral Infections: Implications for COVID-19

Mesenchymal stromal cells (MSCs) constitute a heterogeneous population of stromal cells with immunomodulatory and regenerative properties that support their therapeutic use. MSCs isolated from many tissue sources replicate vigorously in vitro and maintain their main biological properties allowing their widespread clinical application. To date, most MSC-based preclinical and clinical trials targeted immune-mediated and inflammatory diseases. Nevertheless, MSCs have antiviral properties and have been used in the treatment of various viral infections in the last years. Here, we revised in detail the biological properties of MSCs and their preclinical and clinical applications in viral diseases, including the disease caused by the severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) infection (COVID-19). Notably, rapidly increasing numbers of MSC-based therapies for COVID-19 have recently been reported. MSCs are theoretically capable of reducing inflammation and promote lung regeneration in severe COVID-19 patients. We critically discuss the rationale, advantages and disadvantages of MSC-based therapies for viral infections and also specifically for COVID-19 and point out some directions in this field. Finally, we argue that MSC-based therapy may be a promising therapeutic strategy for severe COVID-19 and other emergent respiratory tract viral infections, beyond the viral infection diseases in which MSCs have already been clinically applied.

A Large-Scale Bank of Organ Donor Bone Marrow and Matched Mesenchymal Stem Cells for Promoting Immunomodulation and Transplant Tolerance

Induction of immune tolerance for solid organ and vascular composite allografts is the Holy Grail for transplantation medicine. This would obviate the need for life-long immunosuppression which is associated with serious adverse outcomes, such as infections, cancers, and renal failure. Currently the most promising means of tolerance induction is through establishing a mixed chimeric state by transplantation of donor hematopoietic stem cells; however, with the exception of living donor renal transplantation, the mixed chimerism approach has not achieved durable immune tolerance on a large scale in preclinical or clinical trials with other solid organs or vascular composite allotransplants (VCA). Ossium Health has established a bank of cryopreserved bone marrow (BM), termed "hematopoietic progenitor cell (HPC), Marrow," recovered from deceased organ donor vertebral bodies. This new source for hematopoietic cell transplant will be a valuable resource for treating hematological malignancies as well as for inducing transplant tolerance. In addition, we have discovered and developed a large source of mesenchymal stem (stromal) cells (MSC) tightly associated with the vertebral body bone fragment byproduct of the HPC, Marrow recovery process. Thus, these vertebral bone adherent MSC (vBA-MSC) are matched to the banked BM obtained from each donor, as opposed to third-party MSC, which enhances safety and potentially efficacy. Isolation and characterization of vBA-MSC from over 30 donors has demonstrated that the cells are no different than traditional BM-MSC; however, their abundance is >1,000-fold higher than obtainable from living donor BM aspirates. Based on our own unpublished data as well as reports published by others, MSC facilitate chimerism, especially at limiting hematopoietic stem and progenitor cell (HSPC) numbers and increase safety by controlling and/or preventing graft-vs.-host-disease (GvHD). Thus, vBA-MSC have the potential to facilitate mixed chimerism, promote complementary peripheral immunomodulatory functions and increase safety of BM infusions. Both HPC, Marrow and vBA-MSC have potential use in current VCA and solid organ transplant (SOT) tolerance clinical protocols that are amenable to "delayed tolerance." Current trials with HPC, Marrow are planned with subsequent phases to include vBA-MSC for tolerance of both VCA and SOT.