Mesenchymal stem cells in the treatment of inflammatory and autoimmune diseases in experimental animal models

The Role of Mesenchymal Stem Cells in Modulating Adaptive Immune Responses in Multiple Sclerosis

Multiple sclerosis (MS) is a chronic autoimmune disease of the central nervous system, leading to significant disability through neurodegeneration. Despite advances in the understanding of MS pathophysiology, effective treatments remain limited. Mesenchymal stem cells (MSCs) have gained attention as a potential therapeutic option due to their immunomodulatory and regenerative properties. This review examines MS pathogenesis, emphasizing the role of immune cells, particularly T cells, in disease progression, and explores MSCs' therapeutic potential. Although preclinical studies in animal models show MSC efficacy, challenges such as donor variability, culture conditions, migratory capacity, and immunological compatibility hinder widespread clinical adoption. Strategies like genetic modification, optimized delivery methods, and advanced manufacturing are critical to overcoming these obstacles. Further research is needed to validate MSCs' clinical application in MS therapy.

Efficacy and safety of mesenchymal stem cells therapy in COVID-19 patients: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND

The coronavirus disease 2019 (COVID-19) has become a serious public health issue. In COVID-19 patients, the elevated levels of inflammatory cytokines lead to the manifestation of COVID-19 symptoms, such as lung tissue edema, lung diffusion dysfunction, acute respiratory distress syndrome (ARDS), secondary infection, and ultimately mortality. Mesenchymal stem cells (MSCs) exhibit anti-inflammatory and immunomodulatory properties, thus providing a potential treatment option for COVID-19. The number of clinical trials of MSCs for COVID-19 has been rising. However, the treatment protocols and therapeutic effects of MSCs for COVID-19 patients are inconsistent. This meta-analysis was performed to systematically determine the safety and efficacy of MSC infusion in COVID-19 patients.

METHODS

We conducted a comprehensive literature search from PubMed/Medline, Web of Science, EMBASE, and Cochrane Library up to 22 November 2023 to screen for eligible randomized controlled trials. Inclusion and exclusion criteria for searched literature were formulated according to the PICOS principle, followed by the use of literature quality assessment tools to assess the risk of bias. Finally, outcome measurements including therapeutic efficacy, clinical symptoms, and adverse events of each study were extracted for statistical analysis.

RESULTS

A total of 14 randomized controlled trials were collected. The results of enrolled studies demonstrated that patients with COVID-19 pneumonia who received MSC inoculation showed a decreased mortality compared with counterparts who received conventional treatment (RR: 0.76; 95% CI [0.60, 0.96]; p = 0.02). Reciprocally, MSC inoculation improved the clinical symptoms in patients (RR: 1.28; 95% CI [1.06, 1.55]; p = 0.009). In terms of immune biomarkers, MSC treatment inhibited inflammation responses in COVID-19 patients, as was indicated by the decreased levels of CRP and IL-6. Importantly, our results showed that no significant differences in the incidence of adverse reactions or serious adverse events were monitored in patients after MSC inoculation.

CONCLUSION

This meta-analysis demonstrated that MSC inoculation is effective and safe in the treatment of patients with COVID-19 pneumonia. Without increasing the incidence of adverse events or serious adverse events, MSC treatment decreased patient mortality and inflammatory levels and improved the clinical symptoms in COVID-19 patients. However, large-cohort randomized controlled trials with expanded numbers of patients are required to further confirm our results.

A Comprehensive Exploration of Therapeutic Strategies in Inflammatory Bowel Diseases: Insights from Human and Animal Studies

Inflammatory bowel disease (IBD) is a collective term for a group of chronic inflammatory enteropathies which are characterized by intestinal inflammation and persistent or frequent gastrointestinal signs. This disease affects more than 3.5 million humans worldwide and presents some similarities between animal species, in particular, dogs and cats. Although the underlying mechanism that triggers the disease is not yet well understood, the evidence suggests a multifactorial etiology implicating genetic causes, environmental factors, microbiota imbalance, and mucosa immune defects, both in humans and in dogs and cats. Conventional immunomodulatory drug therapies, such as glucocorticoids or immunosuppressants, are related with numerous adverse effects that limit its long-term use, creating the need to develop new therapeutic strategies. Mesenchymal stromal cells (MSCs) emerge as a promising alternative that attenuates intestinal inflammation by modulating inflammatory cytokines in inflamed tissues, and also due to their pro-angiogenic, anti-apoptotic, anti-fibrotic, regenerative, anti-tumor, and anti-microbial potential. However, this therapeutic approach may have important limitations regarding the lack of studies, namely in veterinary medicine, lack of standardized protocols, and high economic cost. This review summarizes the main differences and similarities between human, canine, and feline IBD, as well as the potential treatment and future prospects of MSCs.

Human umbilical cord mesenchymal stem cells improve disease characterization of Sjogren's syndrome in NOD mice through regulation of gut microbiota and Treg/Th17 cellular immunity

BACKGROUND

For the unclear pathogenesis of Sjogren's syndrome (SS), further exploration is necessary. Mesenchymal stem cells (MSCs) and derived exosomes (MSCs-exo) have exhibited promising results in treating SS.

OBJECT

This study aimed to investigate the effect and mechanism of human umbilical cord MSCs (UC-MSCs) on SS.

METHODS

Nonobese Diabetic (NOD) mouse splenic T cells were co-cultured with UC-MSCs and UC-MSCs-exo, and interferon-gamma (IFN-γ), interleukin (IL)-6, IL-10, prostaglandin E2 (PGE2), and transforming growth factor-β1 (TGF-β1) levels in the supernatant were assessed by quantitative real-time polymerase chain reaction and enzyme-linked immunosorbent assay. Co-cultured T cells were injected into NOD mice via the tail vein. The inflammatory cell infiltration in the intestine and the submandibular gland was characterized by hematoxylin-eosin staining. Treg/Th17 homeostasis within the spleen was determined by flow cytometry. Gut microbiota was detected by 16S rRNA sequencing, and the relationship between differential microbiota and Treg/Th17 cytokines was analyzed by the Pearson correlation coefficient.

RESULTS

UC-MSCs, UC-MSCs-exo, and NOD mouse splenic T cells were successfully cultured and identified. After T cells were co-cultured with UC-MSCs and UC-MSCs-exo, both IFN-γ and IL-6 were decreased while IL-10, PGE2, and TGF-β1 were increased in transcriptional and translational levels. UC-MSCs and UC-MSCs-exo partially restored salivary secretion function, reduced Ro/SSA antibody and α-Fodrin immunoglobulin A levels, reduced inflammatory cell infiltration in the intestine and submandibular gland, raised proportion of Treg cells, decreased IFN-γ, IL-6, IL-2, IL-17, lipopolysaccharide, and tumor necrosis factor-alpha levels, and raised IL-10, Foxp3, and TGF-β1 levels by affecting co-cultured T cells. The intervention of UC-MSCs and UC-MSCs-exo improved intestinal homeostasis in NOD mice by increasing microbiota diversity and richness. Additionally, differential microbiota was significantly associated with Treg/Th17 cytokine levels.

CONCLUSION

Human UC-MSCs and UC-MSCs-exo improved disease characterization of SS in NOD mice through regulation of gut microbiota and Treg/Th17 cellular immunity.

Therapeutic potentials of mesenchymal stem cells in the treatment of inflammatory bowel disease in rats

Interleukin-1beta (IL-1β) and interleukin-17A (IL-17A) have strong pro-inflammatory activities that are involved in inflammatory bowel diseases (IBDs). Mesenchymal stem cell (MSC) therapy is considered a promising treatment for IBD. This study was performed to understand the role of rat Nlrp3 inflammasome, Hmgb1, and pro-inflammatory cytokines (IL-1β and IL-17a) in the pathogenesis of IBD. Also, to evaluate the role of human umbilical cord blood-MSCs (hUCB-MSCs) in the management of IBD. The rats were in four groups: normal controls, indomethacin-induced IBD group, indomethacin-induced IBD rats that received phosphate-buffered saline (PBS), and the IBD group that received hUCB-MSCs as a treatment. The messenger RNA (mRNA) expression levels of rat Nlrp3, Hmgb1, IL-1β, and IL-17a were evaluated by quantitative real-time polymerase chain reaction. Histopathological examination of the small intestinal tissues of the studied rats was performed. There was a significant upregulation of the rat Nlrp3, IL-1β, IL-17a mRNA expression (p < 0.001 for the three parameters), and Hmgb1 (p < 0.05) in the untreated IBD group compared to the normal control group. In the MSC-treated group, IL-1β, IL-17a, and rat Nlrp3 mRNA expression significantly decreased compared to both the untreated IBD group and PBS group (p < 0.05 for all). hUCB-MSCs ameliorated IBD in rats by downregulating the pro-inflammatory cytokines (IL-1β and IL-17a) and other inflammatory mediators such as Hmgb1 and rat Nlrp3.

Advantages of mesenchymal stem cell over the other stem cells

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

Mesenchymal stem cell therapy: A review of clinical trials for multiple sclerosis

Multiple sclerosis (MS) is a disease of the central nervous system (CNS) that is the result of the body's own immune cells being auto-reactive to the myelin regions of the body as if these regions were foreign antigens. This demyelination process is damaging to the electrical conductivity of neurons. The current medicines are only capable of fighting off the symptoms of the disease, but not the disease itself. Specialized stem cells, known as mesenchymal stem cells (MSCs), seem to be the candidate therapy to get rid of MS. MSCs can be isolated from multiple sources of the person's body, and even from the umbilical cord (UC) and placenta of a donor. These cells have anti-inflammatory effects so they can target the overactivity and self-antigen attacks by T cells and macrophages; this immune system overactivity is characteristic of MS. MSCs show the ability to locate into brain lesions when injected and thus can compensate for the loss of the brain function by differentiating into neuronal precursor cells and glial cells. The author has listed tables of clinical trials that have utilized MSCs from different sources, along with the years and the phase of study completed for each trial. The consensus is that these cells work on inhibiting CD4⁺ and CD8⁺ T cell activation, T regulatory cells (Tregs), and macrophage switch into the auto-immune phenotype.

The best source of MSCs seems to be the UC due to the easiness of extraction, the noninvasive method of collection, their higher expansion ability and more powerful immune-modulating properties compared to other locations in the body. Studies showed there was a significant decline of mRNA expression of several cytokines after the administration of MSCs derived from the UC (UCMSCs). Other researchers were able to repair the defects of Tregs in MS patients by co-culturing Tregs from these patients with UCMSCs, which decreased the production of the pro-inflammatory cytokine IFN γ, and also suggested a strong link between Tregs lack of functionality in MS patients with the pathogenesis of the disease.

Comparison of EV-free fraction, EVs, and total secretome of amniotic mesenchymal stromal cells for their immunomodulatory potential: a translational perspective

Amniotic mesenchymal stromal cells (hAMSCs) have unique immunomodulatory properties demonstrated in vitro and in vivo in various diseases in which the dysregulated immune system plays a major role. The immunomodulatory and pro-regenerative effects of MSCs, among which hAMSCs lie in the bioactive factors they secrete and in their paracrine activity, is well known. The mix of these factors (i.e., secretome) can be either freely secreted or conveyed by extracellular vesicles (EV), thus identifying two components in the cell secretome: EV-free and EV fractions. This study aimed to discern the relative impact of the individual components on the immunomodulatory action of the hAMSC secretome in order to obtain useful information for implementing future therapeutic approaches using immunomodulatory therapies based on the MSC secretome. To this aim, we isolated EVs from the hAMSC secretome (hAMSC-CM) by ultracentrifugation and validated the vesicular product according to the International Society for Extracellular Vesicles (ISEV) criteria. EVs were re-diluted in serum-free medium to maintain the EV concentration initially present in the original CM. We compared the effects of the EV-free and EV fractions with those exerted by hAMSC-CM in toto on the activation and differentiation of immune cell subpopulations belonging to both the innate and adaptive immune systems.

We observed that the EV-free fraction, similar to hAMSC-CM in toto, a) decreases the proliferation of activated peripheral blood mononuclear cells (PBMC), b) reduces the polarization of T cells toward inflammatory Th subsets, and induces the induction of regulatory T cells; c) affects monocyte polarization to antigen-presenting cells fostering the acquisition of anti-inflammatory macrophage (M2) markers; and d) reduces the activation of B lymphocytes and their maturation to plasma cells. We observed instead that all investigated EV fractions, when used in the original concentrations, failed to exert any immunomodulatory effect, even though we show that EVs are internalized by various immune cells within PBMC. These findings suggest that the active component able to induce immune regulation, tested at original concentrations, of the hAMSC secretome resides in factors not conveyed in EVs. However, EVs isolated from hAMSC could exert actions on other cell types, as reported by others.

Evaluation of the Therapeutic Potential of Mesenchymal Stem Cells (MSCs) in Preclinical Models of Autoimmune Diseases

Autoimmune diseases, chronic in nature, are generally hard to alleviate. Present long-term treatments with available drugs such as steroids, immune-suppressive drugs, or antibodies have several debilitating side effects. Therefore, new treatment options are urgently needed. Stem cells, in general, have the potential to reduce immune-mediated damage through immunomodulation and T cell regulation (T regs) by inhibiting the proliferation of dendritic cells and T and B cells and reducing inflammation through the generation of immunosuppressive biomolecules like interleukin 10 (IL-10), transforming growth factor-β (TGF-β), nitric oxide (NO), indoleamine 2,3-dioxygenase (IDO), and prostaglandin E2 (PGE2). Many stem cell-based therapeutics have been evaluated in the clinic, but the overall clinical outcomes in terms of efficacy and the longevity of therapeutic benefits seem to be variable and inconsistent with the postulated benefits. This emphasizes a greater need for building robust preclinical models and models that can better predict the clinical translation of stem cell-based therapeutics. Stem cell therapy based on MSCs having the definitive potential to regulate the immune system and control inflammation is emerging as a promising tool for the treatment of autoimmune disorders while promoting tissue regeneration. MSCs, derived from bone marrow, umbilical cord, and adipose tissue, have been shown to be highly immunomodulatory and anti-inflammatory and shown to enhance tissue repair and regeneration in preclinical models as well as in clinical settings. In this article, a review on the status of MSC-based preclinical disease models with emphasis on understanding disease mechanisms in chronic inflammatory disorders caused by exaggerated host immune response in rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE) was carried out. We also emphasized various factors that better predict the translation of stem cell therapeutic outcomes from preclinical disease models to human patients.

Mesenchymal stem cells for critical limb ischemia: their function, mechanism, and therapeutic potential

Peripheral arterial disease is atherosclerotic occlusive disease of the lower extremity arteries and afflicts hundreds of millions of individuals worldwide. Its most severe manifestation is chronic limb-threatening ischemia (Petersen et al. (Science 300(5622):1140–2, 2003)), which is associated with severe pain at rest in the limbs, which progresses to necrosis, limb amputation, and/or death of the patient. Consequently, the care of these patients is considered a financial burden for both patients and health systems. Multidisciplinary endeavors are required to address this refractory disease and to find definitive solutions that lead to improved living conditions. Revascularization is the cornerstone of therapy for preventing limb amputation, and both open vascular surgery and endovascular therapy play a key role in the treatment of patients with CLI. Around one-third of these patients are not candidates for conventional surgical treatment, however, leading to higher amputation rates (approaching 20–25% at one year) with high morbidity and lower quality of life. Advances in regenerative medicine have enabled the development of cell-based therapies that promote the formation of new blood vessels. Particularly, mesenchymal stem cells (MSCs) have emerged as an attractive therapeutic agent in various diseases, including CLI, due to their role in tissue regeneration and immunomodulation. This review discusses the characteristics of MSCs, as well as their regenerative properties and their action mechanisms on CLI.

Investigation of the effect of IFN-γ/TNF-α-treated mesenchymal stem cells on Th9- and Treg cell-related parameters in a mouse model of ovalbumin-induced allergic asthma

OBJECTIVE

Th9- and regulatory T (Treg) cells exert pro- and anti-allergic activity, respectively. Mesenchymal stem cell (MSC)-related immunomodulatory impacts can be enhanced by inflammatory cytokines. Here, the modulatory effects of IFN-γ/TNF-α-induced MSCs on Th9- and Treg cell-related parameters were investigated using an asthma model.

METHODS

Allergic asthma was induced in BALB/c mice using sensitized and challenging with ovalbumin (OVA). The asthmatic groups were treated intraperitoneally with PBS, MSCs, IFN-γ-induced MSCs, TNF-α-induced MSCs and "IFN-γ + TNF-α"-induced MSCs before the challenge phase. The mice were sacrificed 24 hours after challenge. The serum IL-9 and IL-35 levels, as well as gene expression of IL-9, PU.1, IL-35-EBI3 and FOXP3 in the lung tissues were assessed using ELISA and real time-PCR, respectively.

RESULTS

The differences of Th9 and Treg-related parameters were not significant between untreated asthmatic mice and those treated with non-induced MSCs. In comparison with untreated asthmatic group, treatment with IFN-γ-induced MSCs significantly reduced serum IL-9 levels, reduced lung expression of IL-9 and PU.1, while increasing serum IL-35 levels as well as lung expression of FOXP3; treatment with TNF-α-induced MSCs significantly reduced serum IL-9 levels as well as lung expression of IL-9, and treatment with "IFN-γ + TNF-α"-induced MSCs significantly modulated all investigated Th9 and Treg-related parameters. In comparison to mice treated with non-induced MSCs, serum IL-9 levels were remarkably decreased in mice treated with IFN-γ-induced and "IFN-γ + TNF-α"-induced MSCs.

CONCLUSIONS

IFN-γ-and "IFN-γ + TNF-α" treated MSCs exerted almost comparable impacts, but were more efficient than TNF-α-exposed MSCs. Thus, IFN-γ alone can be sufficient to promote immunomodulatory effects of MSCs.

Systemic Treatment of Immune-Mediated Keratoconjunctivitis Sicca with Allogeneic Stem Cells Improves the Schirmer Tear Test Score in a Canine Spontaneous Model of Disease

Keratoconjunctivitis sicca (KCS) is characterized by ocular discomfort, conjunctival hyperaemia, and corneal scarring, causing reduced aqueous tear production that can be measured using the standard Schirmer tear test (STT). Canine adipose tissue-derived MSCs (cATMSCs) have been proposed as treatment due to their anti-inflammatory effect, by releasing cytokines and immunomodulatory soluble factors.

PURPOSE

The aim of this study was to evaluate the effect of the systemic administration of cATMSCs on tear production in dogs with immune-mediated KCS, compared to classical Cyclosporine A (CsA) treatment.

METHODS

Twenty-eight client-owned dogs with spontaneous KCS were allocated in the experimental group (n = 14, treated with systemic cATMSCs or control group (n = 14, treated with CsA). SST values increased significantly at days 15 (p = 0.002), 45 (p = 0.042) and 180 (p = 0.005) with no observed side-effects in the experimental group. Eyes with an initial STT value of 11-14 mm/min maintained significant improvement at day 180, needing only artificial tears as treatment. Eyes with an initial STT value <11 mm/min needed cyclosporin treatment at day 45, so follow-up was stopped. Control animals treated with CsA did not improve their STT at day 180.

RESULTS AND CONCLUSIONS

Systemic allogeneic cATMSCs application appeared to be a feasible and effective therapy with positive outcome in dogs with initial STT between 11-14 mm/min, with a significant improvement in tear production. The STT increment was maintained for at least 180 days, without needing additional medication, thus suggesting it could constitute an alternative therapy to classical immunosuppressive treatments.

Cancer treatment evolution from traditional methods to stem cells and gene therapy

BACKGROUND

Cancer, a malignant tumor, is caused by the failure of the mechanism that controls cell growth and proliferation. Late clinical symptoms often manifest as lumps, pain, ulcers, and bleeding. Systemic symptoms include weight loss, fatigue, and loss of appetite. It is a major disease that threatens human life and health. How to treat cancer is a long-standing problem that needs to be overcome in the history of medicine.

METHOD

Traditional tumor treatment methods are poorly targeted, and the side effects of treatment seriously damage the physical and mental health of patients. In recent years, with the advancement of medical science and technology, the research on gene combined with mesenchymal stem cells to treat tumors has been intensified. Mesenchymal stem cells carry genes to target cancer cells, which can achieve better therapeutic effects.

DISCUSSION

In the text, we systematically review the cancer treatment evolution from traditional methods to novel approaches that include immunotherapy, nanotherapy, stem cell theapy, and gene therapy. We provide the latest review of the application status, clinical trials and development prospects of mesenchymal stem cells and gene therapy for cancer, as well as their integration in cancer treatment. Mesenchymal stem cells are effective carriers carrying genes and provide new clinical ideas for tumor treatment.

CONCLUSION

This review focuses on the current status, application prospects and challenges of mesenchymal stem cell combined gene therapy for cancer, and provides new ideas for clinical research.

Mesenchymal stem cells and COVID-19: What they do and what they can do

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) or coronavirus disease 2019 (COVID-19) pandemic has exhausted the health systems in many countries with thousands cases diagnosed daily. The currently used treatment guideline is to manage the common symptoms like fever and cough, but doesn't target the virus itself or halts serious complications arising from this viral infection. Currently, SARS-CoV-2 exhibits many genetic modulations which have been associated with the appearance of highly contagious strains. The number of critical cases of COVID-19 increases markedly, and many of the infected people die as a result of respiratory failure and multiple organ dysfunction. The regenerative potential of mesenchymal stem cells (MSCs) has been extensively studied and confirmed. The impressive immunomodulation and anti-inflammatory activity of MSCs have been recognized as a golden opportunity for the treatment of COVID-19 and its associated complications. Moreover, MSCs regenerative and repairing abilities have been corroborated by many studies with positive outcomes and high recovery rates. Based on that, MSCs infusion could be an effective mechanism in managing and stemming the serious complications and multiple organ failure associated with COVID-19. In the present review, we discuss the commonly reported complications of COVID-19 viral infection and the established and anticipated role of MSCs in managing these complications.

Options for imaging cellular therapeutics in vivo: a multi-stakeholder perspective

Cell-based therapies have been making great advances toward clinical reality. Despite the increase in trial activity, few therapies have successfully navigated late-phase clinical trials and received market authorization. One possible explanation for this is that additional tools and technologies to enable their development have only recently become available. To support the safety evaluation of cell therapies, the Health and Environmental Sciences Institute Cell Therapy-Tracking, Circulation and Safety Committee, a multisector collaborative committee, polled the attendees of the 2017 International Society for Cell & Gene Therapy conference in London, UK, to understand the gaps and needs that cell therapy developers have encountered regarding safety evaluations in vivo. The goal of the survey was to collect information to inform stakeholders of areas of interest that can help ensure the safe use of cellular therapeutics in the clinic. This review is a response to the cellular imaging interests of those respondents. The authors offer a brief overview of available technologies and then highlight the areas of interest from the survey by describing how imaging technologies can meet those needs. The areas of interest include imaging of cells over time, sensitivity of imaging modalities, ability to quantify cells, imaging cellular survival and differentiation and safety concerns around adding imaging agents to cellular therapy protocols. The Health and Environmental Sciences Institute Cell Therapy-Tracking, Circulation and Safety Committee believes that the ability to understand therapeutic cell fate is vital for determining and understanding cell therapy efficacy and safety and offers this review to aid in those needs. An aim of this article is to share the available imaging technologies with the cell therapy community to demonstrate how these technologies can accomplish unmet needs throughout the translational process and strengthen the understanding of cellular therapeutics.

Adipose-derived mesenchymal stem cell-secreted exosome alleviates dextran sulfate sodium-induced acute colitis by Treg cell induction and inflammatory cytokine reduction

Inflammatory bowel disease (IBD), including Crohn's disease and ulcerative colitis, is an inflammatory condition that results in gastrointestinal tract damage. Various factors, including environmental and genetic agents, disrupt the function of the intestinal immune system that can lead to IBD. Mesenchymal stem cells (MSCs) display an immunoregulatory function and demonstrate regenerative potential by paracrine action. In this study, we evaluated the immunomodulatory effects of MSCs' derived exosomes in the acute form of dextran sulfate sodium (DSS)-induced colitis. Exosomes were isolated from adipose-derived MSCs. Acute colitis was induced by DSS. The exosome was used by intraperitoneal injection into mice with acute colitis. Stool consistency, body weight changes, bleeding severity, colon length, and weight were examined. At the experimental endpoint (Day 7), the changes in the colon tissue were evaluated. The level of cytokines of interferon-γ (IFN-γ), tumor necrosis factor-α (TNF-α), interleukin-17 (IL-17), IL-4, IL-12, transforming growth factor-β (TGF-β) and, IL-10, and Treg cells percentage were assayed. Results showed that exosome administration diminished colon shortening, bodyweight loss, bleeding, and colon injury. The levels of IFN-γ, TNF-α, IL-12, and IL-17 were decreased, and the level of TGF-β, IL-4, and IL-10 were increased in lymph node and spleen of mice treated with exosome.  Percentages of CD4+ CD25+ Foxp3+ Treg cells were grown in the lymph node and spleen of mice treated with exosomes. Overall, current data suggest that MSC-derived exosome could regulate the Treg population and improves inflammation in DSS-induced acute colitis.

Modulation of T-Cell Activation Markers Expression by the Adipose Tissue-Derived Mesenchymal Stem Cells of Patients with Rheumatic Diseases

Background:

Activated T lymphocytes play an important role in the pathogenesis of rheumatic diseases (RD). Mesenchymal stem cells (MSCs) possess immunoregulatory activities but such functions of MSCs from bone marrow of systemic lupus erythematosus (SLE), systemic sclerosis (SSc), and ankylosing spondylitis (AS) patients are impaired. Adipose tissue–derived MSCs (ASCs) are an optional pool of therapeutically useful MSCs, but biology of these cells in RD is poorly known. This study aimed at investigating the effect of ASCs from RD patients and healthy donors (HD) on the expression of the key T-cell activation markers.

Methods:

ASCs were isolated from subcutaneous abdominal fat from SLE (n = 16), SSc (n = 18), and AS (n = 16) patients, while five human ASCs lines from HD were used as a control. Untreated and cytokine (tumor necrosis factor α + interferon γ)-treated ASCs were co-cultured with allogenic, mitogen (phytohemagglutinin)-stimulated peripheral blood mononuclear cells (PBMCs) or purified anti-CD3/CD28-activated CD4⁺ T lymphocytes. Contacting and noncontacting ASCs-PBMCs co-cultures were performed. RD/ASCs were analyzed in co-cultures with both allogeneic and autologous PBMCs. Flow cytometry analysis was used to evaluate expression of CD25, HLA-DR, and CD69 molecules on CD4⁺ and CD8⁺ cells.

Results:

In co-cultures with allogeneic, activated CD4⁺ T cells and PBMCs, HD/ASCs and RD/ASCs downregulated CD25 and HLA-DR, while upregulated CD69 molecules expression on both CD4⁺ and CD8⁺ cells with comparable potency. This modulatory effect was similar in contacting and noncontacting co-cultures. RD/ASCs exerted weaker inhibitory effect on CD25 expression on autologous than allogeneic CD4⁺ and CD8⁺ T cells.

Conclusion:

RD/ASCs retain normal capability to regulate expression of activation markers on allogeneic T cells. Both HD/ASCs and RD/ASCs exert this effect independently of their activation status, mostly through the indirect pathway and soluble factors. However, autologous CD4⁺ and CD8⁺ T cells are partially resistant to RD/ASCs inhibition of CD25 expression, suggesting weaker control of T-cell activation in vivo.

Evaluation of Edaravone effects on the differentiation of human adipose derived stem cells into oligodendrocyte cells in multiple sclerosis disease in rats

AIMS

Among all the treatments for Multiple Sclerosis, stem cell transplantation, such as ADSCs, has attracted a great deal of scientific attention. On the other hand, Edaravone, as an antioxidant component, in combination with stem cells, could increase the survival and differentiation potential of stem cells.

MAIN METHODS

42 rats were divided into: Control, Cuprizone (CPZ), Sham, Edaravone (Ed), hADSCs, and Ed/hADSCs groups. Following induction of cuprizone, induced MS model, behavioral tests were designed to evaluate motor function during. Luxal fast blue staining was done to measure the level of demyelination and remyelination. Immunofluorescent staining was used to evaluate the amount of MBP, OLIG2, and MOG proteins. The mRNA levels of human MBP, MOG, and OLIG2 and rat Mbp, Mog, and Olig2 were determined via RT-PCR.

KEY FINDINGS

Flow cytometry analysis exhibited that the extracted cells were positive for CD73 (93.8 ± 3%) and CD105 (91.6 ± 3%), yet negative for CD45 (2.06 ± 0.5%). Behavioral tests, unveiled a significant improvement in the Ed (P < 0.001), hADSCs (P < 0.001), and Ed/hADSCs (P < 0.001) groups compared to the others. In the Ed/hADSCs group, the myelin density was significantly higher than that in the Ed treated and hADSCs treated groups (P < 0.01). Edaravone and hADSCs increased the expression of Mbp, Mog, and Olig2 genes in the cuprizone rat models. Moreover, significant differences were seen between the Ed treated and hADSCs treated groups and the Ed/hADSCs group (P < 0.05 for Mbp and Olig2 and P < 0.01 for Mog).

SIGNIFICANCE

Edaravone in combination with hADSCs reduced demyelination and increased oligodendrogenesis in the cuprizone rat models.

CD44 fucosylation on bone marrow-derived mesenchymal stem cells enhances homing and promotes enteric nervous system remodeling in diabetic mice

Background

Diabetes can cause extensive enteric nervous system (ENS) injuries and gastrointestinal motility disorder. In developing possible treatments, researchers have engaged in tissue regeneration engineering with the very promising bone marrow-derived mesenchymal stem cells (BMSCs). However, BMSCs have poor homing ability to the targeted tissues after intravenous injection. Thus, we aimed to investigate whether enhancing the expression of E-selectin ligand on BMSCs could improve their homing ability and subsequently influence their role in ENS remodeling in diabetic mice.

Methods

First, we constructed the fucosylation modification of CD44 on BMSCs through a fucosyltransferase VII (FTVII) system to generate a Hematopoietic Cell E-/L-selectin Ligand (HCELL) property, a fucosylated sialyllactosaminyl glycovariant of CD44 that potently binds E-selectin. Next, FTVII-modified and unmodified BMSCs labeled with green fluorescent protein (GFP) were injected into diabetic mice through the tail vein to compare their homing ability to the gastrointestinal tract and their effect on ENS remodeling, respectively. A bioluminescent imaging system was used to evaluate the homing ability of GFP-labeled BMSCs with and without FTVII modification, to the gastrointestinal tract. Gastrointestinal motility was assessed by gastrointestinal transient time, defecation frequency, stool water content and colon strips contractility. Immunofluorescence staining and western blotting were used to assess the expression levels of protein gene product 9.5 (PGP9.5), glial fibrillary acidic protein (GFAP) and glial cell line-derived neurotrophic factor (GDNF).

Results

The FTVII-mediated α(1,3)-fucosylation modification of CD44 on BMSCs generated a HCELL property. Bioluminescent imaging assays showed that FTVII-modified BMSCs had enhanced homing ability to gastrointestinal tract, mainly to the colon, 24 h after injection through the tail vein. Compared with diabetic mice, FTVII-modified BMSCs significantly promoted the gastrointestinal motility and the ENS remodeling, including intestinal peristalsis (P < 0.05), increased feces excretion (P < 0.05) and the water content of the feces (P < 0.05), restored the spontaneous contraction of the colon (P < 0.05), and upregulated the protein expression levels of PGP9.5 (P < 0.01), GFAP (P < 0.001), and GDNF (P < 0.05), while unmodified BMSCs did not (P > 0.05).

Conclusions

CD44 fucosylation modification on murine BMSCs promotes homing ability to the gastrointestinal tract and ENS remodeling in diabetic mice.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13578-021-00632-2.

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

Objective

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

Background

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

Methods

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

Results

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

Conclusions

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

In Vivo Study for Clinical Application of Dental Stem Cell Therapy Incorporated with Dental Titanium Implants

The aim of this study was to investigate the behavior of dental-derived human mesenchymal stem cells (d-hMSCs) in response to differently surface-treated implants and to evaluate the effect of d-hMSCs on local osteogenesis around an implant in vivo. d-hMSCs derived from alveolar bone were established and cultured on machined, sandblasted and acid-etched (SLA)-treated titanium discs with and without osteogenic induction medium. Their morphological and osteogenic potential was assessed by scanning electron microscopy (SEM) and real-time polymerase chain reaction (RT-PCR) via mixing of 5 × 10⁶ of d-hMSCs with 1 mL of Metrigel and 20 μL of gel-cell mixture, which was dispensed into the defect followed by the placement of customized mini-implants (machined, SLA-treated implants) in New Zealand white rabbits. Following healing periods of 2 weeks and 12 weeks, the obtained samples in each group were analyzed radiographically, histomorphometrically and immunohistochemically. The quantitative change in osteogenic differentiation of d-hMSCs was identified according to the type of surface treatment. Radiographic analysis revealed that an increase in new bone formation was statistically significant in the d-hMSCs group. Histomorphometric analysis was in accordance with radiographic analysis, showing the significantly increased new bone formation in the d-hMSCs group regardless of time of sacrifice. Human nuclei A was identified near the area where d-hMSCs were implanted but the level of expression was found to be decreased as time passed. Within the limitations of the present study, in this animal model, the transplantation of d-hMSCs enhanced the new bone formation around an implant and the survival and function of the stem cells was experimentally proven up to 12 weeks post-sacrifice.

Continuing Effect of Cytokines and Toll-Like Receptor Agonists on Indoleamine-2,3-Dioxygenase-1 in Human Periodontal Ligament Stem/Stromal Cells

Transplanted mesenchymal stem/stromal cells (MSCs) are a promising and innovative approach in regenerative medicine. Their regenerative potential is partly based upon their immunomodulatory activities. One of the most investigated immunomediators in MSCs, such as in periodontal ligament-derived MSCs (hPDLSCs), is indoleamine-2,3-dioxygenase-1 (IDO-1) which is upregulated by inflammatory stimuli, like cytokines. However, there are no data concerning continuing IDO-1 expression in hPDLSCs after the removal of inflammatory stimuli, such as cytokines and toll-like receptor (TLR) agonist-2 and TLR-3. Hence, primary hPDLSCs were stimulated with interleukin (IL)-1β, tumor necrosis factor (TNF)-α, interferon (IFN)-γ, TLR-2 agonist Pam3CSK4 or TLR-3 agonist Poly I/C. IDO-1 gene and protein expression and its enzymatic activity were measured up to five days after removing any stimuli. IL-1β- and TNF-α-induced IDO-1 expression and enzymatic activity decreased in a time-dependent manner after cessation of stimulation. IFN-γ caused a long-lasting effect on IDO-1 up to five days after removing IFN-γ. Both, TLR-2 and TLR-3 agonists induced a significant increase in IDO-1 gene expression, but only TLR-3 agonist induced significantly higher IDO-1 protein expression and enzymatic activity in conditioned media (CM). IDO-1 activity of Poly I/C- and Pam3CSK4-treated hPDLSCs was higher at one day after removal of stimuli than immediately after stimulation and declined to basal levels after five days. Among all tested stimuli, only IFN-γ was able to induce long-lasting IDO-1 expression and activity in hPDLSCs. The high plasticity of IDO-1 expression and its enzymatic activity in hPDLSCs due to the variable cytokine and virulence factor milieu and the temporal-dependent responsiveness of hPDLSCs may cause a highly dynamic potential of hPDLSCs to modulate immune responses in periodontal tissues.

Canine Bone Marrow Mesenchymal Stem Cell Conditioned Media Affect Bacterial Growth, Biofilm-Associated Staphylococcus aureus and AHL-Dependent Quorum Sensing

The present study investigated the in vitro antibacterial, antibiofilm and anti-Quorum Sensing (anti-QS) activities of canine bone marrow mesenchymal stem cell-conditioned media (cBM MSC CM) containing all secreted factors <30 K, using a disc diffusion test (DDT), spectrophotometric Crystal Violet Assay (SCVA) and Bioluminescence Assay (BA) with QS-reporter Escherichia coli JM109 pSB1142. The results show a sample-specific bacterial growth inhibition (zones varied between 7–30 mm), statistically significant modulation of biofilm-associated Staphylococcus aureus and Escherichia coli bioluminescence (0.391 ± 0.062 in the positive control to the lowest 0.150 ± 0.096 in the experimental group, cf. 11,714 ± 1362 to 7753 ± 700, given as average values of absorbance A₅₅₀ ± SD versus average values of relative light units to growth RLU/A₅₅₀ ± SD). The proteomic analysis performed in our previous experiment revealed the presence of several substances with documented antibacterial, antibiofilm and immunomodulatory properties (namely, apolipoprotein B and D; amyloid-β peptide; cathepsin B; protein S100-A4, galectin 3, CLEC3A, granulin, transferrin). This study highlights that cBM MSC CM may represent an important new approach to managing biofilm-associated and QS signal molecule-dependent bacterial infections. To the best of our knowledge, there is no previous documentation of canine BM MSC CM associated with in vitro antibiofilm and anti-QS activity.

Mass spectrometric analysis of the in vitro secretome from equine bone marrow-derived mesenchymal stromal cells to assess the effect of chondrogenic differentiation on response to interleukin-1β treatment

Background

Similar to humans, the horse is a long-lived, athletic species. The use of mesenchymal stromal cells (MSCs) is a relatively new frontier, but has been used with promising results in treating joint diseases, e.g., osteoarthritis. It is believed that MSCs exert their main therapeutic effects through secreted trophic biomolecules. Therefore, it has been increasingly important to characterize the MSC secretome. It has been shown that the effect of the MSCs is strongly influenced by the environment in the host compartment, and it is a crucial issue when considering MSC therapy. The aim of this study was to investigate differences in the in vitro secreted protein profile between naïve and chondrogenic differentiating bone marrow-derived (BM)-MSCs when exposed to an inflammatory environment.

Methods

Equine BM-MSCs were divided into a naïve group and a chondrogenic group. Cells were treated with normal expansion media or chondrogenic media. Cells were treated with IL-1β for a period of 5 days (stimulation), followed by 5 days without IL-1β (recovery). Media were collected after 48 h and 10 days. The secretomes were digested and analyzed by nanoLC-MS/MS to unravel the orchestration of proteins.

Results

The inflammatory proteins IL6, CXCL1, CXCL6, CCL7, SEMA7A, SAA, and haptoglobin were identified in the secretome after 48 h from all cells stimulated with IL-1β. CXCL8, OSM, TGF-β1, the angiogenic proteins VCAM1, ICAM1, VEGFA, and VEGFC, the proteases MMP1 and MMP3, and the protease inhibitor TIMP3 were among the proteins only identified in the secretome after 48 h from cells cultured in normal expansion media. After 10-day incubation, the proteins CXCL1, CXCL6, and CCL7 were still identified in the secretome from BM-MSCs stimulated with IL-1β, but the essential inducer of inflammation, IL6, was only identified in the secretome from cells cultured in normal expansion media.

Conclusion

The findings in this study indicate that naïve BM-MSCs have a more extensive inflammatory response at 48 h to stimulation with IL-1β compared to BM-MSCs undergoing chondrogenic differentiation. This extensive inflammatory response decreased after 5 days without IL-1β (day 10), but a difference in composition of the secretome between naïve and chondrogenic BM-MSCs was still evident.

Cytokines Differently Define the Immunomodulation of Mesenchymal Stem Cells from the Periodontal Ligament

Human periodontal ligament stem cells (hPDLSCs) play an important role in periodontal tissue homeostasis and regeneration. The function of these cells in vivo depends largely on their immunomodulatory ability, which is reciprocally regulated by immune cells via cytokines, particularly interferon (IFN)-γ, tumor necrosis factor (TNF)-α, and interleukin (IL)-1β. Different cytokines activate distinct signaling pathways and might differently affect immunomodulatory activities of hPDLSCs. This study directly compared the effect of IFN-γ, TNF-α, or IL-1β treated primary hPDLSCs on allogenic CD4⁺ T lymphocyte proliferation and apoptosis in an indirect co-culture model. The effects of IFN-γ, TNF-α, and IL-1β on the expression of specific immunomodulatory factors such as intoleamine-2,3-dioxygenase-1 (IDO-1), prostaglandin E₂ (PGE₂), and programmed cell death 1 ligand 1 (PD-L1) and ligand 2 (PD-L2) in hPDLSCs were compared. The contribution of different immunomodulatory mediators to the immunomodulatory effects of hPDLSCs in the indirect co-culture experiments was assessed using specific inhibitors. Proliferation of CD4⁺ T lymphocytes was inhibited by hPDLSCs, and this effect was strongly enhanced by IFN-γ and IL-1β but not by TNF-α. Apoptosis of CD4⁺ T lymphocytes was decreased by hPDLSCs per se. This effect was counteracted by IFN-γ or IL-1β. Additionally, IFN-γ, TNF-α, and IL-1β differently regulated all investigated immunomediators in hPDLSCs. Pharmacological inhibition of immunomediators showed that their contribution in regulating CD4⁺ T lymphocytes depends on the cytokine milieu. Our data indicate that inflammatory cytokines activate specific immunomodulatory mechanisms in hPDLSCs and the expression of particular immunomodulatory factors, which underlies a complex reciprocal interaction between hPDLSCs and CD4⁺ T lymphocytes.

Harnessing mesenchymal stem cell secretome: Effect of extracellular matrices on proangiogenic signaling

The low engraftment and retention rate of mesenchymal stem cells (MSCs) at the target site indicates that the potential benefits of MSC-based therapies can be attributed to their paracrine signaling. In this study, the extracellular matrices (ECMs) deposited by bone marrow-derived human MSCs in the presence and absence of ascorbic acid was characterized. MSCs were seeded on top of decellularized ECM (dECM) and the concentrations of proangiogenic and antiangiogenic molecules released in culture (conditioned) media was compared. Effects of ECM derived from MSCs with different passage numbers on MSC secretome was also investigated. Our study revealed that the expression of proangiogenesis-related factors were upregulated when MSCs were harvested on dECMs, irrespective of media supplementation, as compared with those cultured on tissue culture plates. In addition, dECM generated in the presence of ascorbic acid promoted the expression of proangiogenic molecules as compared with dECM-derived in absence of media supplementation. Further, it was observed that the effectiveness of dECM to stimulate proangiogenic signaling of MSCs was reduced as cell passage number was increased from P3 to P5. The proliferation as well as capillary morphogenesis of human umbilical vein endothelial cells (HUVECs) in the presence of conditioned media were enhanced compared with the normal HUVECs culture media. These data indicate that the secretory signatures of MSCs and consequently, the therapeutic efficacy of MSCs can be regulated by presentation of dECM composition and variation of its composition.

Human adipose stem cell-derived extracellular nanovesicles for treatment of chronic liver fibrosis

Liver fibrosis is an excessive wound healing process that occurs in response to liver damage depending on underlying aetiologies. Currently, there are no effective therapies and FDA-approved therapeutics for the treatment of liver fibrosis except liver transplantation. Multipotent adipose-derived stem cells (ADSCs) have received significant attention as regenerative medicine for liver fibrosis owing to their advantages over stem cells with other origins. However, intrinsic limitations of stem cell therapies, such as cellular rejection and tumor formation, have impeded clinical applications of the ADSC-based liver therapeutics. To overcome these problems, the extracellular nanovesicles (ENVs) responsible for the therapeutic effect of ADSCs (A-ENVs) have shown considerable promise as cell-free therapeutics for liver diseases. However, A-ENVs have not been used for the treatment of intractable chronic liver diseases including liver fibrosis and cirrhosis. Therefore, in this study, we investigated the in vitro and in vivo antifibrotic efficacy of A-ENVs in thioacetamide-induced liver fibrosis models. A-ENVs significantly downregulated the expression of fibrogenic markers, such as matrix metalloproteinase-2, collagen-1, and alpha-smooth muscle actin. The systemic administration of A-ENVs led to high accumulation in fibrotic liver tissue and the restoration of liver functionality in liver fibrosis models through a marked reduction in α-SMA and collagen deposition. These results demonstrate the significant potential of A-ENVs for use as extracellular nanovesicles-based therapeutics in the treatment of liver fibrosis and possibly other intractable chronic liver diseases.

Safety and efficacy of stem cell therapy for treatment of neural damage in patients with multiple sclerosis

Multiple sclerosis (MS) is a multifocal inflammatory disease that involves the central nervous system and associated with limbs paralysis and serious problems in sensation, limbs, visual and sphincter. This disease is a result of autoimmune mechanism in which autoantibodies target the self-myelin antigens and cause demyelination. Because of the myelin dysfunction, MS is clinically identified with neurological disabilities. Furthermore, it can be entered into the progressive phase because of irreversible neurodegeneration and axons damage. Unfortunately, there is no effective therapeutic method for this disease and current medications have been focused on amelioration of symptoms and chronic inflammation. Although current immunotherapies ameliorate the reactivity of autoimmune anti-myelin and MS relapse rate, there is no approved method for improvement of the disease progression and repairing of the damaged myelin. Therefore, finding an appropriate clinical treatment for improvement of neurological damages in MS patients is essential. Mesenchymal stem cells (MSCs) are multipotent cells with high proliferative and self-renewal capacities, as well as immunomodulatory and neuroregenerative effects. Bone marrow and adipose tissues derived MSCs have been considered for the treatment of different diseases because not only they can be easily isolated from these tissues, but also a patient can be served as a donor for himself without the risk of rejection. More importantly, autologous MSCs carry a safer pattern without the risk of malignant transformation. Here, we will discuss the effectiveness of MSCs therapy for MS patients by reviewing of clinical trials.

The Phenotype and Secretory Activity of Adipose-Derived Mesenchymal Stem Cells (ASCs) of Patients with Rheumatic Diseases

Mesenchymal stem/stromal cells (MSCs) have immunosuppressive and regenerative properties. Adipose tissue is an alternative source of MSCs, named adipose-derived mesenchymal stem cells (ASCs). Because the biology of ASCs in rheumatic diseases (RD) is poorly understood, we performed a basic characterization of RD/ASCs. The phenotype and expression of adhesion molecules (intracellular adhesion molecule (ICAM)-1 and vascular cell adhesion molecule (VCAM)-1) on commercially available healthy donors (HD), ASC lines (n = 5) and on ASCs isolated from patients with systemic lupus erythematosus (SLE, n = 16), systemic sclerosis (SSc, n = 17) and ankylosing spondylitis (AS, n = 16) were analyzed by flow cytometry. The secretion of immunomodulatory factors by untreated and cytokine-treated ASCs was measured by ELISA. RD/ASCs have reduced basal levels of CD90 and ICAM-1 expression, correlated with interleukin (IL)-6 and transforming growth factor (TGF)-β1 release, respectively. Compared with HD/ASCs, untreated and tumour necrosis factor (TNF) + interferon (IFN)-γ (TI)-treated RD/ASCs produced similar amounts of prostaglandin E2 (PGE2), IL-6, leukemia inhibiting factor (LIF), and TGF-β1, more IL-1Ra, soluble human leukocyte antigen G (sHLA-G) and tumor necrosis factor-inducible gene (TSG)-6, but less kynurenines and galectin-3. Basal secretion of galectin-3 was inversely correlated with the patient's erythrocyte sedimentation rate (ESR) value. IFN-α and IL-23 slightly raised galectin-3 release from SLE/ASCs and AS/ASCs, respectively. TGF-β1 up-regulated PGE2 secretion by SSc/ASCs. In conclusion, RD/ASCs are characterized by low basal levels of CD90 and ICAM-1 expression, upregulated secretion of IL-1Ra, TSG-6 and sHLA-G, but impaired release of kynurenines and galectin-3. These abnormalities may modify biological activities of RD/ASCs.

Scaffold-based tissue engineering approaches in treating infertility

Tissue engineering and the use of scaffolds have shown high therapeutic potentialities about male and female infertility. Nowadays, many couples are suffering from infertility problems. There are different causes for infertility including chemotherapy (for male and female), uterine injuries, and intrauterine adhesions. Extra-cellular matrix in tissue engineering provides a supportive medium for blood or lymphatic vessels making it a suitable substrate for cell implantation and growth. Dominant successes in this branch have been in use of patient-derived primary cells, these cells loaded in scaffolds and used to generate tissue for re-implantation. However, this method has limitations, because of the invasive nature of cell collection, also the cells patient-derived may be not healthy and become the source of disease. Therefore, use of stem cells, including embryonic stem (ES) cells, bone marrow mesenchymal stem cells (BM-MSCs) and umbilical cord-derived mesenchymal stem cells (UC-MSCs) have been considered. Cell/scaffold systems have a substantial role in fertility organs or agents repair or regeneration. This review summarizes the novel scaffold-based tissue engineering approaches to treat infertility.

Mesenchymal stem cells as carrier of the therapeutic agent in the gene therapy of blood disorders

Nonhematopoietic stem cells as a delivery platform of therapeutic useful genes have attracted widespread attention in recent years, owing to gained a long lifespan, easy separation, high proliferation, and high transfection capacity. Mesenchymal stem/stromal cells (MSCs) are the choice of the cells for gene and cell therapy due to high self-renewal capacity, high migration rate to the site of the tumor, and with immune suppressive and anti-inflammatory properties. Hence, it has a high potential of safety genetic modification of MSCs for antitumor gene expression and has paved the way for the clinical application of these cells to target the therapy of cancers and other diseases. The aim of gene therapy is targeted treatment of cancers and diseases through recovery, change, or enhancement cell performance to the sustained secretion of useful therapeutic proteins and induction expression of the functional gene in intended tissue. Recent developments in the vectors designing leading to the increase and durability of expression and improvement of the safety of the vectors that overcome a lot of problems, such as durability of expression and the host immune response. Nowadays, gene therapy approach is used by MSCs as a delivery vehicle in the preclinical and the clinical trials for the secretion of erythropoietin, recombinant antibodies, coagulation factors, cytokines, as well as angiogenic inhibitors in many blood disorders like anemia, hemophilia, and malignancies. In this study, we critically discuss the status of gene therapy by MSCs as a delivery vehicle for the treatment of blood disorders. Finally, the results of clinical trial studies are assessed, highlighting promising advantages of this emerging technology in the clinical setting.

Mesenchymal stem cells therapy in companion animals: useful for immune-mediated diseases?

Mesenchymal stem cells are multipotent cells, with capacity for self-renewal and differentiation into tissues of mesodermal origin. These cells are possible therapeutic agents for autoimmune disorders, since they present remarkable immunomodulatory ability.The increase of immune-mediated diseases in veterinary medicine has led to a growing interest in the research of these disorders and their medical treatment. Conventional immunomodulatory drug therapy such as glucocorticoids or other novel therapies such as cyclosporine or monoclonal antibodies are associated with numerous side effects that limit its long-term use, leading to the need for developing new therapeutic strategies that can be more effective and safe.The aim of this review is to provide a critical overview about the therapeutic potential of these cells in the treatment of some autoimmune disorders (canine atopic dermatitis, feline chronic gingivostomatitis, inflammatory bowel disease and feline asthma) compared with their conventional treatment.Mesenchymal stem cell-based therapy in autoimmune diseases has been showing that this approach can ameliorate clinical signs or even cause remission in most animals, with the exception of canine atopic dermatitis in which little to no improvement was observed.Although mesenchymal stem cells present a promising future in the treatment of most of these disorders, the variability in the outcomes of some clinical trials has led to the current controversy among authors regarding their efficacy. Mesenchymal stem cell-based therapy is currently requiring a deeper and detailed analysis that allows its standardization and better adaptation to the intended therapeutic results, in order to overcome current limitations in future trials.

Protective effect of umbilical cord mesenchymal stem cells combined with resveratrol against renal podocyte damage in NOD mice

BACKGROUND

The role of chronic inflammation initiated by persistent hyperglycemia in podocyte injury has attracted increasing attention. The advanced glycation end products (RAGE) receptor- nuclear factor-kappa B (NF-кB) signaling pathway is involved in the occurrence of inflammation. We speculate that treatment with human umbilical cord mesenchymal stem cells (hUCMSCs) combined with resveratrol can block this signaling pathway and protect podocyte function.

METHODS

Non obesity diabetes(NOD) mice were randomly divided into 5 groups: NOD-T1DM, Res, hUCMSCs, hUCMSCs + Res and insulin (INS)groups. Mice without diabetes were classified as NOD control group(NOD group). Blood glucose(BG), blood urea nitrogen(BUN), serum creatinine(SCr), 24-h urine albumin excretion rate (UAER) were measured. The expression of nephrin, WT1 and RAGE, MCP-1 in renal tissues were detected by Western blot, expression of NF-кB protein(P65) was determined by immunohistochemistry.

RESULTS

The combined treatment of hUCMSCs and Resveratrol can reduce BG, BUN, SCr, 24-h UAER, and the expression of the inflammatory factors MCP-1, RAGE and NF-кB; increase the number of podocytes and the expression of the podocyte-related proteins nephrin and WT1 in type 1 diabetes mellitus, and improve renal pathological structure.

CONCLUSIONS

Combining of hUCMSCs and resveratrol can better protect renal podocyte function, and the effects on the reduction of blood glucose and renal injury are better than those obtained by insulin treatment. This indicated that the combination of Res and hUCMSCs may be a novel therapeutic method for the treatment of DN.

IFN-γ-tethered hydrogels enhance mesenchymal stem cell-based immunomodulation and promote tissue repair

Because of their immunomodulatory activities, human mesenchymal stem cells (hMSCs) are being explored to treat a variety of chronic conditions such as inflammatory bowel disorders and graft-vs-host disease. Treating hMSCs with IFN-γ prior to administration augments these immunomodulatory properties; however, this ex vivo treatment limits the broad applicability of this therapy due to technical and regulatory issues. In this study, we engineered an injectable synthetic hydrogel with tethered recombinant IFN-γ that activates encapsulated hMSCs to increase their immunomodulatory functions and avoids the need for ex vivo manipulation. Tethering IFN-γ to the hydrogel increases retention of IFN-γ within the biomaterial while preserving its biological activity. hMSCs encapsulated within hydrogels with tethered IFN-γ exhibited significant differences in cytokine secretion and showed a potent ability to halt activated T-cell proliferation and monocyte-derived dendritic cell differentiation compared to hMSCs that were pre-treated with IFN-γ and untreated hMSCs. Importantly, hMSCs encapsulated within hydrogels with tethered IFN-γ accelerated healing of colonic mucosal wounds in both immunocompromised and immunocompetent mice. This novel approach for licensing hMSCs with IFN-γ may enhance the clinical translation and efficacy of hMSC-based therapies.

Adipose-derived Stem Cells Attenuates Diabetic Osteoarthritis via Inhibition of Glycation-mediated Inflammatory Cascade

Diabetes mellitus (DM) is well-known to exert complications such as retinopathy, cardiomyopathy and neuropathy. However, in recent years, an elevated osteoarthritis (OA) complaints among diabetics have been observed, portending the risk of diabetic OA. Since formation of advanced glycation end products (AGE) is believed to be the etiology of various diseases under hyperglycemic conditions, we firstly established that streptozotocin-induced DM could potentiate the development of OA in C57BL/6J mouse model, and further explored the intra-articularly administered adipose-derived stem cell (ADSC) therapy focusing on underlying AGE-associated mechanism. Our results demonstrated that hyperglycemic mice exhibited OA-like structural impairments including a proteoglycan loss and articular cartilage fibrillations in knee joint. Highly expressed levels of carboxymethyl lysine (CML), an AGE and their receptors (RAGE), which are hallmarks of hyperglycemic microenvironment were manifested. The elevated oxidative stress in diabetic OA knee-joint was revealed through increased levels of malondialdehyde (MDA). Further, oxidative stress-activated nuclear factor kappa B (NF-κB), the marker of proinflammatory signalling pathway was also accrued; and levels of matrix metalloproteinase-1 and 13 were upregulated. However, ADSC treatment attenuated all OA-like changes by 4 weeks, and dampened levels of CML, RAGE, MDA, NF-κB, MMP-1 and 13. These results suggest that during repair and regeneration, ADSCs inhibited glycation-mediated inflammatory cascade and rejuvenated cartilaginous tissue, thereby promoting knee-joint integrity in diabetic milieu.

Identification of Proteins Differentially Expressed by Adipose-derived Mesenchymal Stem Cells Isolated from Immunodeficient Mice

Although cell therapy using adipose-derived mesenchymal stem cells (AdMSCs) regulates immunity, the degree to which cell quality and function are affected by differences in immunodeficiency of donors is unknown. We used liquid chromatography tandem-mass spectrometry (LC MS/MS) to identify the proteins expressed by mouse AdMSCs (mAsMSCs) isolated from normal (C57BL/6) mice and mice with severe combined immunodeficiency (SCID). The protein expression profiles of each strain were 98%–100% identical, indicating that the expression levels of major proteins potentially associated with the therapeutic effects of mAdMSCs were highly similar. Further, comparable levels of cell surface markers (CD44, CD90.2) were detected using flow cytometry or LC MS/MS. MYH9, ACTN1, CANX, GPI, TPM1, EPRS, ITGB1, ANXA3, CNN2, MAPK1, PSME2, CTPS1, OTUB1, PSMB6, HMGB1, RPS19, SEC61A1, CTNNB1, GLO1, RPL22, PSMA2, SYNCRIP, PRDX3, SAMHD1, TCAF2, MAPK3, RPS24, and MYO1E, which are associated with immunity, were expressed at higher levels by the SCID mAdMSCs compared with the C57BL/6 mAdMSCs. In contrast, ANXA9, PCBP2, LGALS3, PPP1R14B, and PSMA6, which are also associated with immunity, were more highly expressed by C57BL/6 mAdMSCs than SCID mAdMSCs. These findings implicate these two sets of proteins in the pathogenesis and maintenance of immunodeficiency.

Intravenously Injected Mesenchymal Stem Cells Penetrate the Brain and Treat Inflammation-Induced Brain Damage and Memory Impairment in Mice

Neuroinflammation is regarded as one of the pathogenic factors of Alzheimer disease (AD). Previously, we showed that mice regularly injected with bacterial lipopolysaccharide (LPS) possessed the AD-like symptoms like episodic memory decline, elevated amounts of amyloid beta (Aβ) peptide (1-42), and decreased levels of nicotinic acetylcholine receptors (nAChRs) in the brain. The use of mesenchymal stem cells (MSCs), which can differentiate into multiple cell types, including neurons, is an attractive idea of regenerative medicine, in particular, for neurodegenerative disorders like AD. In the present study, we aimed to investigate whether pathogenic effect of LPS on the brain and behavior of mice can be prevented or treated by injection of MSCs or MSC-produced soluble factors. Fluorescently-labeled MSCs, injected intravenously, were found in the brain blood vessels of LPS-treated mice. Mice co-injected with LPS and MSCs did not demonstrate episodic memory impairment, Aβ (1-42) accumulation, and nAChR decrease in the brain and brain mitochondria. Their mitochondria released less cytochrome c under the effect of Ca²⁺ compared to mitochondria of LPS-only-treated mice. Moreover, MSCs could reverse the pathogenic symptoms developed 3 weeks after LPS injection. Cultured MSCs produced IL-6 in response to LPS and MSCs effect in vivo was accompanied by additional stimulation of both micro- and macroglia. Xenogeneic (human) MSCs were almost as efficient as allogeneic (mouse) ones and regular injections of human MSC-conditioned medium also produced positive effect. These data allow suggesting MSCs as a potential therapeutic tool to cure neuroinflammation-related cognitive pathology.

Preliminary Studies of the Impact of CXCL12 on the Foreign Body Reaction to Pancreatic Islets Microencapsulated in Alginate in Nonhuman Primates

Supplemental Digital Content is available in the text.

Background.

We previously demonstrated that the incorporation of the chemokine CXCL12 into alginate microbeads supported long-term survival of microencapsulated auto-, allo-, and xenogeneic islets in murine models of diabetes without systemic immune suppression. The purpose of this study was to test whether CXCL12 could abrogate foreign body responses (FBRs) against alginate microbeads which were empty or contained autologous islets in healthy nonhuman primates (NHPs; n = 4).

Methods.

Two NHPs received intraperitoneal implants of 400 000 alginate microbeads with or without CXCL12, and postimplantation immunological and histopathological changes were evaluated up to 6 months postimplantation. A similar evaluation of autologous islets in CXCL12-containing alginate microbeads was performed in NHPs (n = 2).

Results.

CXCL12-containing alginate microbeads were associated with a markedly reduced FBR to microbeads. Host responses to microbead implants were minimal, as assessed by clinical observations, blood counts, and chemistry. Evaluation of encapsulated islets was limited by the development of necrotizing pancreatitis after hemipancreatectomy in 1 NHP. A limited number of functioning islets were detectable at 6 months posttransplantation in the second NHP. In general, empty microbeads or islet-containing beads were found to be evenly distributed through the intraperitoneal cavity and did not accumulate in the Pouch of Douglas.

Conclusions.

Inclusion of CXCL12 in alginate microbeads minimized localized FBR. The NHP autologous islet implant model had limited utility for excluding inflammatory/immune responses to implanted islets because of the complexity of pancreatic surgery (hemipancreatectomy) before transplantation and the need to microencapsulate and transplant encapsulated autologous islets immediately after pancreatectomy and islet isolation.

Regulatory Dendritic Cells Induced by Mesenchymal Stem Cells Ameliorate Dextran Sodium Sulfate-Induced Chronic Colitis in Mice

Background/Aims

Regulatory dendritic cells (rDCs), which can be induced by mesenchymal stem cells (MSCs), play an important role in inducing and maintaining homeostasis of regulatory T cells and exhibit anti-inflammatory functions. In this study, we investigated whether MSCs could differentiate DCs into rDCs and compared the therapeutic effects of rDCs and MSCs on dextran sodium sulfate (DSS)-induced chronic colitis mice.

Methods

Immature DCs (imDCs) and lipopolysaccharide (LPS)-treated mature DCs (mDCs) were co-cultured with MSCs for 48 hours, and then the profiles of surface markers and cytokines and regulatory roles of these DCs for primary splenocytes were analyzed. In addition, the therapeutic effects of MSCs and DCs co-cultured with MSCs were compared in chronic colitis mice.

Results

After co-culture of imDCs (MSC-DCs) or LPS-treated mDCs (LPS+MSC-DCs) with MSCs, the expression of CD11c, CD80, CD86, interleukin 6 (IL-6), tumor necrosis factor-α (TNF-α), and interferon-γ (IFN-γ), was decreased, but that of CD11b, IL-10, and transforming growth factor-β (TGF-β) was increased. Furthermore, MSC-DCs and LPS+MSC-DCs induced the expression of CD4, CD25, and Foxp3 in primary splenocytes isolated from mice. In DSS-induced colitis mice, MSCs and MSC-DCs increased colon length, body weight, and survival rate and induced histological improvement. Moreover, in the colon tissues, the expression of IL-6, TNF-α, and IFN-γ decreased, but that of IL-10, TGF-β, and Foxp3 increased in the MSC- and MSC-DC-injected groups.

Conclusions

Our data suggest that MSCs differentiate DCs into rDCs, which ameliorate chronic colitis. Thus, rDCs stimulated by MSCs may be therapeutically useful for the treatment of chronic inflammatory diseases.

Extracellular micro/nanovesicles rescue kidney from ischemia-reperfusion injury

Acute renal failure (ARF) is a clinical challenge that is highly resistant to treatment, and its high rate of mortality is alarming. Ischemia-reperfusion injury (IRI) is the most common cause of ARF. Especially IRI is implicated in kidney transplantation and can determine graft survival. Although the exact pathophysiology of renal IRI is unknown, the role of inflammatory responses has been elucidated. Because mesenchymal stromal cells (MSCs) have strong immunomodulatory properties, they are under extensive investigation as a therapeutic modality for renal IRI. Extracellular vesicles (EVs) play an integral role in cell-to-cell communication. Because the regenerative potential of the MSCs can be recapitulated by their EVs, the therapeutic appeal of MSC-derived EVs has dramatically increased in the past decade. Higher safety profile and ease of preservation without losing function are other advantages of EVs compared with their producing cells. In the current review, the preliminary results and potential of MSC-derived EVs to alleviate kidney IRI are summarized. We might be heading toward a cell-free approach to treat renal IRI.

Morphological profiling using machine learning reveals emergent subpopulations of interferon-γ-stimulated mesenchymal stromal cells that predict immunosuppression

BACKGROUND

Although a preponderance of pre-clinical data demonstrates the immunosuppressive potential of mesenchymal stromal cells (MSCs), significant heterogeneity and lack of critical quality attributes (CQAs) based on immunosuppressive capacity likely have contributed to inconsistent clinical outcomes. This heterogeneity exists not only between MSC lots derived from different donors, tissues and manufacturing conditions, but also within a given MSC lot in the form of functional subpopulations. We therefore explored the potential of functionally relevant morphological profiling (FRMP) to identify morphological subpopulations predictive of the immunosuppressive capacity of MSCs derived from multiple donors, manufacturers and passages.

METHODS

We profiled the single-cell morphological response of MSCs from different donors and passages to the functionally relevant inflammatory cytokine interferon (IFN)-γ. We used the machine learning approach visual stochastic neighbor embedding (viSNE) to identify distinct morphological subpopulations that could predict suppression of activated CD4⁺ and CD8⁺ T cells in a multiplexed quantitative assay.

RESULTS

Multiple IFN-γ-stimulated subpopulations significantly correlated with the ability of MSCs to inhibit CD4⁺ and CD8⁺ T-cell activation and served as effective CQAs to predict the immunosuppressive capacity of additional manufactured MSC lots. We further characterized the emergence of morphological heterogeneity following IFN-γ stimulation, which provides a strategy for identifying functional subpopulations for future single-cell characterization and enrichment techniques.

DISCUSSION

This work provides a generalizable analytical platform for assessing functional heterogeneity based on single-cell morphological responses that could be used to identify novel CQAs and inform cell manufacturing decisions.

Current Status of Stem Cell Treatment for Type I Diabetes Mellitus

BACKGROUND

Diabetes mellitus is a major health concern in current scenario which has been found to affect people of almost all ages. The disease has huge impact on global health; therefore, alternate methods apart from insulin injection are being explored to cure diabetes. Therefore, this review mainly focuses on the current status and therapeutic potential of stem cells mainly mesenchymal stem cells (MSCs) for Type 1 diabetes mellitus in preclinical animal models as well as humans.

METHODS

Current treatment for Type 1 diabetes mellitus mainly includes use of insulin which has its own limitations and also the underlying mechanism of diseases is still not explored. Therefore, alternate methods to cure diabetes are being explored. Stem cells are being investigated as an alternative therapy for treatment of various diseases including diabetes. Few preclinical studies have also been conducted using undifferentiated MSCs as well as in vitro MSCs differentiated into β islet cells.

RESULTS

These stem cell transplant studies have highlighted the benefits of MSCs, which have shown promising results. Few human trials using stem cells have also affirmed the potential of these cells in alleviating the symptoms.

CONCLUSION

Stem cell transplantation may prove to be a safe and effective treatment for patients with Type 1 diabetes mellitus.

Trophic Effects of Mesenchymal Stem Cells in Tissue Regeneration

Mesenchymal stem cells (MSCs) are considered to hold great therapeutic value for cell-based therapy and for tissue regeneration in particular. Recent evidence indicates that the main underlying mechanism for MSCs' beneficial effects in tissue regeneration is based on their capability to produce a large variety of bioactive trophic factors that stimulate neighboring parenchymal cells to start repairing damaged tissues. These new findings could potentially replace the classical paradigm of MSC differentiation and cell replacement. These bioactive factors have diverse actions like modulating the local immune system, enhancing angiogenesis, preventing cell apoptosis, and stimulating survival, proliferation, and differentiation of resident tissue specific cells. Therefore, MSCs are referred to as conductors of tissue repair and regeneration by secreting trophic mediators. In this review article, we have summarized the studies that focused on the trophic effects of MSC within the context of tissue regeneration. We will also highlight the various underlying mechanisms used by MSCs to act as trophic mediators. Besides the secretion of growth factors, we discuss two additional mechanisms that are likely to mediate MSC's beneficial effects in tissue regeneration, namely the production of extracellular vesicles and the formation of membrane nanotubes, which can both connect different cells and transfer a variety of trophic factors varying from proteins to mRNAs and miRNAs. Furthermore, we postulate that apoptosis of the MSCs is an integral part of the trophic effect during tissue repair.

Intraperitoneal infusion of mesenchymal stem cell attenuates severity of collagen antibody induced arthritis

It is unclear how systemic administration of mesenchymal stem cells (MSCs) controls local inflammation. The aim of this study was to evaluate the therapeutic effects of human MSCs on inflammatory arthritis and to identify the underlying mechanisms. Mice with collagen antibody-induced arthritis (CAIA) received two intraperitoneal injections of human bone marrow-derived MSCs. The clinical and histological features of injected CAIA were then compared with those of non-injected mice. The effect of MSCs on induction of regulatory T cells was examined both in vitro and in vivo. We also examined multiple cytokines secreted by peritoneal mononuclear cells, along with migration of MSCs in the presence of stromal cell-derived factor-1 alpha (SDF-1α) and/or regulated on activation, normal T cell expressed and secreted (RANTES). Sections of CAIA mouse joints and spleen were stained for human anti-nuclear antibodies (ANAs) to confirm migration of injected human MSCs. The results showed that MSCs alleviated the clinical and histological signs of synovitis in CAIA mice. Peritoneal lavage cells from mice treated with MSCs expressed higher levels of SDF-1α and RANTES than those from mice not treated with MSCs. MSC migration was more prevalent in the presence of SDF-1α and/or RANTES. MSCs induced CD4+ T cells to differentiate into regulatory T cells in vitro, and expression of FOXP3 mRNA was upregulated in the forepaws of MSC-treated CAIA mice. Synovial and splenic tissues from CAIA mice receiving human MSCs were positive for human ANA, suggesting recruitment of MSCs. Taken together, these results suggest that MSCs migrate into inflamed tissues and directly induce the differentiation of CD4+ T cells into regulatory T cells, which then suppress inflammation. Thus, systemic administration of MSCs may be a therapeutic option for rheumatoid arthritis.

Therapeutic Delivery Specifications Identified Through Compartmental Analysis of a Mesenchymal Stromal Cell-Immune Reaction

Despite widespread preclinical success, mesenchymal stromal cell (MSC) therapy has not reached consistent pivotal clinical endpoints in primary indications of autoinflammatory diseases. Numerous studies aim to uncover specific mechanisms of action towards better control of therapy using in vitro immunomodulation assays. However, many of these immunomodulation assays are imperfectly designed to accurately recapitulate microenvironment conditions where MSCs act. To increase our understanding of MSC efficacy, we herein conduct a systems level microenvironment approach to define compartmental features that can influence the delivery of MSCs' immunomodulatory effect in vitro in a more quantitative manner than ever before. Using this approach, we notably uncover an improved MSC quantification method with predictive cross-study applicability and unveil the key importance of system volume, time exposure to MSCs, and cross-communication between MSC and T cell populations to realize full therapeutic effect. The application of these compartmental analysis can improve our understanding of MSC mechanism(s) of action and further lead to administration methods that deliver MSCs within a compartment for predictable potency.