Conditioned mesenchymal stem cells produce pleiotropic gut trophic factors

Therapeutic Prospects of Mesenchymal Stem Cell and Their Derived Exosomes in the Regulation of the Gut Microbiota in Inflammatory Bowel Disease

Mesenchymal stem cells (MSCs) have shown great potential in the treatment of several inflammatory diseases due to their immunomodulatory ability, which is mediated by exosomes secreted by MSCs (MSC-Exs). The incidence of inflammatory bowel disease (IBD) is increasing globally, but there is currently no long-term effective treatment. As an emerging therapy, MSC-Exs have proven to be effective in alleviating IBD experimentally, and the specific mechanism continues to be explored. The gut microbiota plays an important role in the occurrence and development of IBD, and MSCs and MSC-Exs can effectively regulate gut microbiota in animal models of IBD, but the mechanism involved and whether the outcome can relieve the characteristic dysbiosis necessary to alleviate IBD still needs to be studied. This review provides current evidence on the effective modulation of the gut microbiota by MSC-Exs, offering a basis for further research on the pathogenic mechanism of IBD and MSC-Ex treatments through the improvement of gut microbiota.

Treatment of gastric ulcer, traditional Chinese medicine may be a better choice

ETHNOPHARMACOLOGICAL RELEVANCE

Gastric ulcer (GU) is the injury of the gastric mucosa caused by the stimulation of various pathogenic factors penetrating the deep mucosal muscle layer. An increasing number of studies have shown that traditional Chinese medicine (TCM) is highly effective in treating GU due to its multitarget, multilevel, and multi-pathway effects.

AIM OF THE STUDY

To review the latest research progress in the treatment of GU by TCM, including clinical and experimental studies, focusing on the target and mechanism of action of drugs and providing a theoretical basis for the treatment of GU by natural herbs.

MATERIALS AND METHODS

Electronic databases (PubMed, Elsevier, Springer, Web of Science, and CNKI) were searched using the keywords "gastric ulcer", "gastric mucosal lesion", "TCM" and or paired with "peptic ulcer" and "natural drugs" for studies published in the last fifteen years until 2023.

RESULTS

TCM, including single components of natural products, Chinese patent medicines (CPM), and TCM decoction, is expected to treat GU by regulating various mechanisms, such as redox balance, inflammatory factors, angiogenesis, gastric mucosal protective factors, intestinal flora, apoptosis, and autophagy.

CONCLUSIONS

We discussed and summarized the mechanism of TCM in the treatment of GU, which provided a sufficient basis for TCM treatment of GU.

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.

Therapeutic potential of mesenchymal stem/stromal cells (MSCs)-based cell therapy for inflammatory bowel diseases (IBD) therapy

Recently, mesenchymal stem/stromal cells (MSCs) therapy has become an emerging therapeutic modality for the treatment of inflammatory bowel disease (IBD), given their immunoregulatory and pro-survival attributes. MSCs alleviate dysregulated inflammatory responses through the secretion of a myriad of anti-inflammatory mediators, such as interleukin 10 (IL-10), transforming growth factor-β (TGFβ), prostaglandin E2 (PGE2), tumor necrosis factor-stimulated gene-6 (TSG-6), etc. Indeed, MSC treatment of IBD is largely carried out through local microcirculation construction, colonization and repair, and immunomodulation, thus alleviating diseases severity. The clinical therapeutic efficacy relies on to the marked secretion of various secretory molecules from viable MSCs via paracrine mechanisms that are required for gut immuno-microbiota regulation and the proliferation and differentiation of surrounding cells like intestinal epithelial cells (IECs) and intestinal stem cells (ISCs). For example, MSCs can induce IECs proliferation and upregulate the expression of tight junction (TJs)-associated protein, ensuring intestinal barrier integrity. Concerning the encouraging results derived from animal studies, various clinical trials are conducted or ongoing to address the safety and efficacy of MSCs administration in IBD patients. Although the safety and short-term efficacy of MSCs administration have been evinced, the long-term efficacy of MSCs transplantation has not yet been verified. Herein, we have emphasized the illumination of the therapeutic capacity of MSCs therapy, including naïve MSCs, preconditioned MSCs, and also MSCs-derived exosomes, to alleviate IBD severity in experimental models. Also, a brief overview of published clinical trials in IBD patients has been delivered.

Mesenchymal Stem Cells Ameliorate DSS-Induced Experimental Colitis by Modulating the Gut Microbiota and MUC-1 Pathway

Purpose

Mesenchymal stem cells (MSCs) have become novel therapeutic agents for the treatment of inflammatory bowel diseases (IBDs). However, the precise cellular and molecular mechanisms by which MSCs restore intestinal tissue homeostasis and repair the epithelial barrier have not been well elucidated. This study aimed to investigate the therapeutic effects and possible mechanisms of human MSCs in the treatment of experimental colitis.

Methods

We performed an integrative transcriptomic, proteomic, untargeted metabolomics, and gut microbiota analyses in a dextran sulfate sodium (DSS)-induced IBD mouse model. The cell viability of IEC-6 cells was determined by Cell Counting Kit-8 (CCK-8) assay. The expression of MUC-1 and ferroptosis-related genes were determined by immunohistochemical staining, Western blot, and real-time quantitative polymerase chain reaction (RT-qPCR).

Results

Mice treated with MSCs showed notable amelioration in the severity of DSS-induced colitis, which was associated with reduced levels of proinflammatory cytokines and restoration of the lymphocyte subpopulation balance. Treatment with MSC restored the gut microbiota and altered their metabolites in DSS-induced IBD mice. The 16s rDNA sequencing showed that treatment with MSC modulated the composition of probiotics, including the upregulation of the contents of Firmicutes, Lactobacillus, Blautia, Clostridia, and Helicobacter bacteria in mouse colons. Protein proteomics and transcriptome analyses revealed that pathways related to cell immune responses, including inflammatory cytokines, were suppressed in the MSC group. The ferroptosis-related gene, MUC-1, was significantly upregulated in the MSC-treated group. MUC-1-inhibition experiments indicated that MUC-1 was essential for epithelial cell growth. Through overexpression of MUC-1, it showed that upregulation of SLC7A11 and GPX4, and downregulation of ACSL4 in erastin and RSL3-treated IEC-6 cells, respectively.

Conclusion

This study described a mechanism by which treatment with MSCs ameliorated the severity of DSS-induced colitis by modulating the gut microbiota, immune response, and the MUC-1 pathway.

Mesenchymal stem cell-based therapy as a new therapeutic approach for acute inflammation

Acute inflammatory diseases such as acute colitis, kidney injury, liver failure, lung injury, myocardial infarction, pancreatitis, septic shock, and spinal cord injury are significant causes of death worldwide. Despite advances in the understanding of its pathophysiology, there are many restrictions in the treatment of these diseases, and new therapeutic approaches are required. Mesenchymal stem cell-based therapy due to immunomodulatory and regenerative properties is a promising candidate for acute inflammatory disease management. Based on preclinical results, mesenchymal stem cells and their-derived secretome improved immunological and clinical parameters. Furthermore, many clinical trials of acute kidney, liver, lung, myocardial, and spinal cord injury have yielded promising results. In this review, we try to provide a comprehensive view of mesenchymal stem cell-based therapy in acute inflammatory diseases as a new treatment approach.

Mesenchymal stem/stromal cells in the pathogenesis and regenerative therapy of inflammatory bowel diseases

Inflammatory bowel diseases (IBDs) represent a group of chronic inflammatory disorders of the gastrointestinal (GI) tract including ulcerative colitis (UC), Crohn’s disease (CD), and unclassified IBDs. The pathogenesis of IBDs is related to genetic susceptibility, environmental factors, and dysbiosis that can lead to the dysfunction of immune responses and dysregulated homeostasis of local mucosal tissues characterized by severe inflammatory responses and tissue damage in GI tract. To date, extensive studies have indicated that IBDs cannot be completely cured and easy to relapse, thus prompting researchers to find novel and more effective therapeutics for this disease. Due to their potent multipotent differentiation and immunomodulatory capabilities, mesenchymal stem/stromal cells (MSCs) not only play an important role in regulating immune and tissue homeostasis but also display potent therapeutic effects on various inflammatory diseases, including IBDs, in both preclinical and clinical studies. In this review, we present a comprehensive overview on the pathological mechanisms, the currently available therapeutics, particularly, the potential application of MSCs-based regenerative therapy for IBDs.

Application of Bone Marrow Mesenchymal Stem Cells Effectively Eliminates Endotoxemia to Protect Rat from Acute Liver Failure Induced by Thioacetamide

BACKGROUND

Endotoxemia is related to worse clinical outcomes in acute liver failure (ALF), but its management remains unsatisfactory. In this study, we aimed to assess whether the application of bone marrow mesenchymal stem cells (BMSCs) could eliminate endotoxemia and protect rats against ALF induced by thioacetamide (TAA).

METHODS

BMSCs were isolated from rats and identified by the specific morphology, differentiation potential, and surface markers. The optimal dose of TAA for this study was explored and TAA-induced ALF rats were randomized to three groups: the normal control group (Saline), ALF group (TAA + Saline), and BMSCs-treated group (TAA + BMSCs). The intestinal migration and differentiation of BMSCs was tracked in vivo, and intestinal permeability, endotoxin and inflammatory cytokines, histology, and mortality were analyzed. Moreover, we added the inhibitor of the PI3K/AKT/mTOR signaling pathway into the co-culture system of BMSCs with enterocytes and then performed CK and Villin expression experiments to assess the role of PI3K/AKT/mTOR signal pathway in the intestinal differentiation of BMSCs.

RESULTS

BMSCs migrated to the intestinal injury sites and differentiated into enterocytes, intestinal permeability was decreased compared with the ALF group. The higher expression of endotoxin and inflammatory cytokines were reversed after BMSCs transplantation in rats with ALF. Mortality and intestinal lesion were significantly decreased. Blocking the PI3K/AKT/mTOR signal pathway inhibited BMSCs' intestinal differentiation in vitro.

CONCLUSION

BMSCs can eliminate endotoxemia and reduce mortality in rats with ALF, and the PI3K/AKT/mTOR signal pathway is involved in intestinal differentiation. BMSCs transplantation could be a potential candidate for the treatment of endotoxemia in ALF.

Treatment of Inflammatory Bowel Disease: A Comprehensive Review

Inflammatory bowel disease (IBD), as a global disease, has attracted much research interest. Constant research has led to a better understanding of the disease condition and further promoted its management. We here reviewed the conventional and the novel drugs and therapies, as well as the potential ones, which have shown promise in preclinical studies and are likely to be effective future therapies. The conventional treatments aim at controlling symptoms through pharmacotherapy, including aminosalicylates, corticosteroids, immunomodulators, and biologics, with other general measures and/or surgical resection if necessary. However, a considerable fraction of patients do not respond to available treatments or lose response, which calls for new therapeutic strategies. Diverse therapeutic options are emerging, involving small molecules, apheresis therapy, improved intestinal microecology, cell therapy, and exosome therapy. In addition, patient education partly upgrades the efficacy of IBD treatment. Recent advances in the management of IBD have led to a paradigm shift in the treatment goals, from targeting symptom-free daily life to shooting for mucosal healing. In this review, the latest progress in IBD treatment is summarized to understand the advantages, pitfalls, and research prospects of different drugs and therapies and to provide a basis for the clinical decision and further research of IBD.

mRNA-engineered mesenchymal stromal cells expressing CXCR2 enhances cell migration and improves recovery in IBD

Mesenchymal stromal cells (MSCs) have shown significant heterogeneity in terms of therapeutic efficacy for inflammatory bowel disease (IBD) treatment, which may be due to an insufficient number of MSCs homing to the damaged tissue of the colon. Engineering MSCs with specific chemokine receptors can enhance the homing ability by lentiviral transduction. However, the unclear specific chemokine profile related to IBD and the safety concerns of viral-based gene delivery limit its application. Thus, a new strategy to modify MSCs to express specific chemokine receptors using mRNA engineering is developed to evaluate the homing ability of MSCs and its therapeutic effects for IBD. We found that CXCL2 and CXCL5 were highly expressed in the inflammatory colon, while MSCs minimally expressed the corresponding receptor CXCR2. Transient expression of CXCR2 in MSC was constructed and exhibited significantly enhanced migration to the inflamed colons, leading to a robust anti-inflammatory effect and high efficacy. Furthermore, the high expression of semaphorins7A on MSCs were found to induce the macrophages to produce IL-10, which may play a critical therapeutic role. This study demonstrated that the specific chemokine receptor CXCR2 mRNA-engineered MSCs not only improves the therapeutic efficacy of IBD but also provides an efficient and safe MSC modification strategy.

Improving the Efficacy of Mesenchymal Stem/Stromal-Based Therapy for Treatment of Inflammatory Bowel Diseases

Inflammatory bowel diseases (IBD) consisting of persistent and relapsing inflammatory processes of the intestinal mucosa are caused by genetic, environmental, and commensal microbiota factors. Despite recent advances in clinical treatments aiming to decrease inflammation, nearly 30% of patients treated with biologicals experienced drawbacks including loss of response, while others can develop severe side effects. Hence, novel effective treatments are highly needed. Mesenchymal stem/stromal cell (MSCs) therapy is an innovative therapeutic alternative currently under investigation for IBD. MSCs have the inherent capacity of modulating inflammatory immune responses as well as regenerating damaged tissues and are therefore a prime candidate to use as cell therapy in patients with IBD. At present, MSC-based therapy has been shown preclinically to modulate intestinal inflammation, whilst the safety of MSC-based therapy has been demonstrated in clinical trials. However, the successful results in preclinical studies have not been replicated in clinical trials. In this review, we will summarize the protocols used in preclinical and clinical trials and the novel approaches currently under investigation which aim to increase the beneficial effects of MSC-based therapy for IBD.

Therapeutic approach of adipose-derived mesenchymal stem cells in refractory peptic ulcer

Peptic ulcer is one of the most common gastrointestinal tract disorders worldwide, associated with challenges such as refractory morbidity, bleeding, interference with use of anticoagulants, and potential side effects associated with long-term use of proton pump inhibitors. A peptic ulcer is a defect in gastric or duodenal mucosa extending from muscularis mucosa to deeper layers of the stomach wall. In most cases, ulcers respond to standard treatments. However, in some people, peptic ulcer becomes resistant to conventional treatment or recurs after initially successful therapy. Therefore, new and safe treatments, including the use of stem cells, are highly favored for these patients. Adipose-derived mesenchymal stem cells are readily available in large quantities with minimal invasive intervention, and isolation of adipose-derived mesenchymal stromal stem cells (ASC) produces large amounts of stem cells, which are essential for cell-based and restorative therapies. These cells have high flexibility and can differentiate into several types of cells in vitro. This article will investigate the effects and possible mechanisms and signaling pathways of adipose tissue-derived mesenchymal stem cells in patients with refractory peptic ulcers.

Achievements and Challenges in Transplantation of Mesenchymal Stem Cells in Otorhinolaryngology

Otorhinolaryngology enrolls head and neck surgery in various tissues such as ear, nose, and throat (ENT) that govern different activities such as hearing, breathing, smelling, production of vocal sounds, the balance, deglutition, facial animation, air filtration and humidification, and articulation during speech, while absence of these functions can lead to high morbidity and even mortality. Conventional therapies for head and neck damaged tissues include grafts, transplants, and artificial materials, but grafts have limited availability and cause morbidity in the donor site. To improve these limitations, regenerative medicine, as a novel and rapidly growing field, has opened a new therapeutic window in otorhinolaryngology by using cell transplantation to target the healing and replacement of injured tissues. There is a high risk of rejection and tumor formation for transplantation of embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs); mesenchymal stem cells (MSCs) lack these drawbacks. They have easy expansion and antiapoptotic properties with a wide range of healing and aesthetic functions that make them a novel candidate in otorhinolaryngology for craniofacial defects and diseases and hold immense promise for bone tissue healing; even the tissue sources and types of MSCs, the method of cell introduction and their preparation quality can influence the final outcome in the injured tissue. In this review, we demonstrated the anti-inflammatory and immunomodulatory properties of MSCs, from different sources, to be safely used for cell-based therapies in otorhinolaryngology, while their achievements and challenges have been described too.

Filtrated Adipose Tissue-Derived Mesenchymal Stem Cell Lysate Ameliorates Experimental Acute Colitis in Mice

BACKGROUND

Inflammatory bowel disease (IBD) is a chronic, persistent, and intractable enteritis; however, an effective treatment strategy is yet to be established. Mesenchymal stem cells (MSCs) and their paracrine factors exhibit anti-inflammatory actions and have been proposed as a new therapeutic candidate for IBD treatment, although the efficacy of MSC lysate on enteritis is unclear.

AIMS

Here, we examined the efficacy and appropriate regimen of filtrated murine adipose-derived mesenchymal stem cell lysate (FADSTL) in an acute colitis mouse model as a novel cell-free MSC therapy.

METHODS

To confirm the clinical effects of FADSTL, survival rate, body weight, and disease activity index (DAI) were investigated in the DSS-induced colitis mouse model. Further, differences in efficacy with dosing frequency were assessed to optimize the proper regimen. Colon length, histological findings, gene expression of inflammatory mediators and tight junction proteins in colon tissues, and anti-apoptotic effects were also compared in 3-day continuous FADSTL administration and PBS groups.

RESULTS

Three-day continuous FADSTL administration significantly improved weight loss and DAI score compared to those in the PBS-treated group, whereas the effect was not observed with single administration. Additionally, colon shortening and histological inflammation were suppressed in the FADSTL-treated group. Further, this treatment decreased gene expression of inflammatory mediators, maintained expression of tight junction proteins in the colon, and showed anti-apoptotic effects.

CONCLUSIONS

FADSTL effects were dependent on its administration frequency, suggesting the requirement of continuous FADSTL administration. FADSTL improved colitis by maintaining the intestinal barrier function through its anti-inflammatory and anti-apoptotic actions.

Stem cells and COVID-19: are the human amniotic cells a new hope for therapies against the SARS-CoV-2 virus?

A new coronavirus respiratory disease (COVID-19) caused by the SARS-CoV-2 virus, surprised the entire world, producing social, economic, and health problems. The COVID-19 triggers a lung infection with a multiple proinflammatory cytokine storm in severe patients. Without effective and safe treatments, COVID-19 has killed thousands of people, becoming a pandemic. Stem cells have been suggested as a therapy for lung-related diseases. In particular, mesenchymal stem cells (MSCs) have been successfully tested in some clinical trials in patients with COVID-19. The encouraging results positioned MSCs as a possible cell therapy for COVID-19. The amniotic membrane from the human placenta at term is a valuable stem cell source, including human amniotic epithelial cells (hAECs) and human mesenchymal stromal cells (hAMSCs). Interestingly, amnion cells have immunoregulatory, regenerative, and anti-inflammatory properties. Moreover, hAECs and hAMSCs have been used both in preclinical studies and in clinical trials against respiratory diseases. They have reduced the inflammatory response and restored the pulmonary tissue architecture in lung injury in vivo models. Here, we review the existing data about the stem cells use for COVID-19 treatment, including the ongoing clinical trials. We also consider the non-cellular therapies that are being applied. Finally, we discuss the human amniotic membrane cells use in patients who suffer from immune/inflammatory lung diseases and hypothesize their possible use as a successful treatment against COVID-19.

Mesenchymal stromal cells to fight SARS-CoV-2: Taking advantage of a pleiotropic therapy

The devastating global impact of the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) has prompted scientists to develop novel strategies to fight Coronavirus Disease of 2019 (COVID-19), including the examination of pre-existing treatments for other viral infections in COVID-19 patients. This review provides a reasoned discussion of the possible use of Mesenchymal Stromal Cells (MSC) or their products as a treatment in SARS-CoV-2-infected patients. The main benefits and concerns of using this cellular therapy, guided by preclinical and clinical data obtained from similar pathologies will be reviewed. MSC represent a highly immunomodulatory cell population and their use may be safe according to clinical studies developed in other pathologies. Notably, four clinical trials and four case reports that have already been performed in COVID-19 patients obtained promising results. The clinical application of MSC in COVID-19 is very preliminary and further investigational studies are required to determine the efficacy of the MSC therapy. Nevertheless, these preliminary studies were important to understand the therapeutic potential of MSC in COVID-19. Based on these encouraging results, the United States Food and Drug Administration (FDA) authorized the compassionate use of MSC, but only in patients with Acute Respiratory Distress Syndrome (ARDS) and a poor prognosis. In fact, patients with severe SARS-CoV-2 can present infection and tissue damage in different organs, such as lung, heart, liver, kidney, gut and brain, affecting their function. MSC may have pleiotropic activities in COVID-19, with the capacity to fight inflammation and repair lesions in several organs.

Therapeutic Effect of Mesenchymal Stem Cells in Ulcerative Colitis: A Review on Achievements and Challenges

The worldwide epidemiology of inflammatory bowel disease (IBD), including Crohn's disease (CD) and ulcerative colitis (UC), still shows an increasing trend in Asia and Iran. Despite an improvement in the treatment landscape focused on symptomatic control, long-term colectomies have not decreased over the last 10-year period. Thus, novel therapies are urgently needed in clinics to supplement the existing treatments. Mesenchymal stem cells (MSCs) are multipotent adult stem cells with immunosuppressive effects, targeting IBD as a new treatment strategy. They have recently received global attention for their use in cell transplantation due to their easy expansion and wide range of activities to be engrafted, and because they are home to the mucosa of the intestine. Moreover, MSCs are able to differentiate into epithelial and other cells that can directly promote repair in the mucosal damages in UC. It seems that there is a need to deepen our understanding to target MSCs as a promising treatment option for UC patients who are refractory to conventional therapies. Here, we overviewed the therapeutic effects of MSCs in UC and discussed the achievements and challenges in the cell transplantation of UC.

CELL THERAPY IN INFLAMMATORY BOWEL DISEASE

In recent years, cell-based therapies have been explored in various immune-mediated inflammatory diseases, including inflammatory bowel disease (IBD). Cell therapy is the process of introducing new cells into an organism or tissue in order to treat a disease. The most studied cellular treatment in IBD was "stem cells-based therapy", which was explored according to different protocols in terms of type of donors, stem cells sources, study design and clinical endpoints. More recently, preliminary studies have also described the clinical use of "regulatory cells", which include T-reg and Tr1 cells, and "tolerogenic" dendritic cells. Finally, induced pluripotent stem cells are the subject of an intensive preclinical research program on animal models, including those related to colitis.

Humoral factors secreted from adipose tissue-derived mesenchymal stem cells ameliorate atherosclerosis in Ldlr-/- mice

AIMS

Atherosclerosis is a chronic inflammatory disease of the vasculature. Mesenchymal stem cells (MSCs) exert immunomodulatory and immunosuppressive effects by secreting humoral factors; however, the intravascular MSC administration presents a risk of vascular occlusion. Here, we investigated both the effect of conditioned medium from cultured MSCs (MSC-CM) on atherosclerosis and the underlying mechanism.

METHODS AND RESULTS

Low-density lipoprotein receptor-deficient (Ldlr-/-) mice were fed a high-fat diet and received intravenous injections of either MSC-CM from adipose tissue-derived MSCs or control medium 2×/week for 13 weeks. MSC-CM treatment decreased the atherosclerotic plaque area in the aorta and aortic root of Ldlr-/- mice by 41% and 30%, respectively, with no change in serum lipoprotein levels. Histopathologically, the MSC-CM treatment decreased the expression of cell adhesion molecules (CAMs) and the accumulation of macrophages on the vascular walls. Extracellular vesicles (EVs) and supernatant (MSC-CM supernatant) were separated from the MSC-CM by ultracentrifugation. In tumour necrosis factor-α stimulated human aortic endothelial cells (HAOECs), both the MSC EVs and MSC-CM supernatant decreased CAM expression by inhibiting the mitogen-activated protein kinase (MAPK) and nuclear factor-kappa B (NFκB) pathways. In macrophages, the MSC-CM supernatant decreased the lipopolysaccharide-induced increases in M1 marker expression by inhibiting both the MAPK and NFκB pathways and increased the expression of M2 markers by activating the signal transducer and activator of transcription 3 pathway. In co-culture, inflamed HAOECs pretreated with MSC-CM supernatant and MSC EVs exhibited decreased monocyte adhesion to HAOECs. In addition, the neutralization of hepatocyte growth factor (HGF) in MSC-CM or MSC-CM supernatant attenuated their abilities to suppress monocyte adhesion to HAOECs in co-culture.

CONCLUSION

MSC-CM ameliorated atherosclerosis in Ldlr-/- mice and suppressed CAM expression and macrophage accumulation in the vascular walls. Humoral factors, including HGF and EVs from MSCs, hold promise as therapeutic agents to reduce the residual risk of coronary artery diseases.

The Achievements and Challenges of Mesenchymal Stem Cell-Based Therapy in Inflammatory Bowel Disease and Its Associated Colorectal Cancer

Approximately 18.1 × 10⁶ new cases of cancer were recorded globally in 2018, out of which 9.6 million died. It is known that people who have Inflammatory Bowel Disease (IBD) turn to be prone to increased risks of developing colorectal cancer (CRC), which has global incident and mortality rates of 10.2% and 9.2%, respectively. Over the years, conventional treatments of IBD and its associated CRC have been noted to provide scarce desired results and often with severe complications. The introduction of biological agents as a better therapeutic approach has witnessed a great deal of success in both experimental and clinical models. With regard to mesenchymal stem cell (MSC) therapy, the ability of these cells to actively proliferate, undergo plastic differentiation, trigger strong immune regulation, exhibit low immunogenicity, and express abundant trophic factors has ensured their success in regenerative medicine and immune intervention therapies. Notwithstanding, MSC-based therapy is still confronted with some challenges including the likelihood of promoting tumor growth and metastasis, and possible overestimated therapeutic potentials. We review the success story of MSC-based therapy in IBD and its associated CRC as documented in experimental models and clinical trials, examining some of the challenges encountered and possible ways forward to producing an optimum MSC therapeutic imparts.

Mesenchymal stem cell-gut microbiota interaction in the repair of inflammatory bowel disease: an enhanced therapeutic effect

Background

Several investigations affirm that, patients with inflammatory bowel disease (IBD) exhibit dysbiosis characterized by restricted biodiversity and imbalanced bacterial composition intertwined with immune dysregulation. The interaction between stem cells and gut microbiota is a novel and highly promising field that could add up to a better understanding of the gut physiology, as well as therapeutic improvement towards diseases like IBD. Through direct contact or release of products and/or metabolites, gut bacteria regulate gut homeostasis, damage repair, regeneration and differentiation of stem cells. In the same way, mesenchymal stem cells (MSCs) produce similar effects including restoration of gut–microbiome composition.

Body

We reviewed the anti-inflammatory, antimicrobial, pathogenic bacterial clearance, proliferation and tissue remodeling effects of mesenchymal stem cells (MSCs) and fecal microbiota transplantation (FMT) as separate transplants in IBD, and the outcome of the interaction between MSCs and gut microbiota.

Conclusion

The two therapies share several points of connection in therapeutics with enhanced functionalities in their interaction with each other. Focused investigations of MSC–gut bacteria interactions could lead to a novel discovery in therapeutics. We also anticipate an improved clinical remission rate in a combined FMT–MSC transplantation approach in IBD than the current single FMT or MSC approach.

Effects of Human Adipose Tissue-Derived and Umbilical Cord Tissue-Derived Mesenchymal Stem Cells in a Dextran Sulfate Sodium-Induced Mouse Model

Mesenchymal stem cells (MSCs) can be acquired from medical waste. MSCs are easily expanded and have multiple functions, including anti-inflammatory effects. We evaluated the effects of human adipose tissue-derived MSCs (AD-MSCs) and umbilical cord tissue-derived MSCs (UC-MSCs) in a dextran sulfate sodium (DSS)-induced mouse model. Human AD-MSCs and UC-MSCs (1 × 10⁶ cells) were injected intravenously into a 7-day DSS-induced colitis model. The therapeutic effects of cell origin, injection timing, and supernatants obtained from MSC cultures were evaluated. We also analyzed messenger RNA (mRNA) expression in MSCs, tissues, and intestinal flora. AD-MSCs and UC-MSCs were found to show strong anti-inflammatory effects when injected on day 3 in a mouse model. On day 11, the mRNA levels of inflammatory factors in colon tissues were significantly decreased after injection of MSCs on day 3. Supernatants from MSCs culture decreased mRNA levels of tumor necrosis factor (Tnf)-α, but had reduced therapeutic effects compared with MSC cell injection. RNA sequencing using colon tissues obtained the day after cell injection revealed changes in the TNF-α/nuclear factor-κB and T cell receptor signaling pathways. Additional analyses showed that several factors, including chromosome 10 open reading frame 54, stanniocalcin-1, and TNF receptor superfamily member 11b were increased in MSCs after adding serum from DSS colitis mice. Furthermore, both AD-MSCs and UC-MSCs maintained the balance of intestinal flora. In conclusion, AD-MSCs and UC-MSCs showed therapeutic effects against inflammation after early cell injection while maintaining the intestinal flora. Although supernatants showed therapeutic effects, cell injection was more effective against inflammation.

Bone marrow-derived mesenchymal stem cells alleviate severe acute pancreatitis-induced multiple-organ injury in rats via suppression of autophagy

Patients with severe acute pancreatitis (SAP) represent a substantial challenge to medical practitioners due to the high associated rates of morbidity and mortality and a lack of satisfactory therapeutic outcomes. In a previous study, our group demonstrated that bone marrow-derived mesenchymal stem cells (BMSCs) can ameliorate SAP; however, the mechanisms of action remain to be fully understood. BMSCs were intravenously injected into SAP rats 12 h after experimental induction of SAP using sodium taurocholate (NaT). Histopathological changes and the levels of pro-inflammatory mediators were assessed by hematoxylin and eosin (H&E) staining and ELISA, respectively. Autophagy levels were assessed using qRT-PCR, western blotting, immunohistochemistry, immunofluorescence, and transmission electron microscopy. AR42J cells and human umbilical vein endothelial cells (HUVECs) were administered BMSC-conditioned media (BMSC-CM) after NaT treatment, and cell viability was measured using a Cell Counting Kit-8 (CCK-8) and flow cytometry. In vivo, BMSCs effectively reduced multiple systematic inflammatory responses, suppressed the activation of autophagy, and improved intestinal dysfunction. In vitro, BMSC-CM significantly improved the viability of injured cells, promoted angiogenesis, and decreased autophagy. We therefore propose that the administration of BMSCs alleviates SAP-induced multiple organ injury by inhibiting autophagy.

Cell membrane and bioactive factors derived from mesenchymal stromal cells: Cell-free based therapy for inflammatory bowel diseases

Inflammatory bowel diseases (IBD) are chronic inflammatory disorders of the gastrointestinal tract associated with multifactorial conditions such as ulcerative colitis and Crohn’s disease. Although the underlying mechanisms of IBD remain unclear, growing evidence has shown that dysregulated immune system reactions in genetically susceptible individuals contribute to mucosal inflammation. However, conventional treatments have been effective in inducing remission of IBD but not in preventing the relapse of them. In this way, mesenchymal stromal cells (MSC) therapy has been recognized as a promising treatment for IBD due to their immunomodulatory properties, ability to differentiate into several tissues, and homing to inflammatory sites. Even so, literature is conflicted regarding the location and persistence of MSC in the body after transplantation. For this reason, recent studies have focused on the paracrine effect of the biofactors secreted by MSC, especially in relation to the immunomodulatory potential of soluble factors (cytokines, chemokines, and growth factors) and extracellular vehicles that are involved in cell communication and in the transfer of cellular material, such as proteins, lipids, and nucleic acids. Moreover, treatment with interferon-γ, tumor necrosis factor-α, and interleukin-1β causes MSC to express immunomodulatory molecules that mediate the suppression via cell-contact dependent mechanisms. Taken together, we present an overview of the role of bioactive factors and cell membrane proteins derived from MSC as a cell-free therapy that can improve IBD treatment.

Ex vivo effect of vascular wall stromal cells secretome on enteric ganglia

BACKGROUND

Mesenchymal stromal cell (MSC)-based therapy is currently under study to treat inflammatory bowel diseases. MSC bioactive products could represent a valid alternative to overcome issues associated with systemic whole-cell therapies. However, MSC anti-inflammatory mechanisms differ between rodents and humans, impairing the reliability of preclinical models.

AIM

To evaluate the effect of conditioned medium (CM) derived from porcine vascular wall MSCs (pVW-MSCs) on survival and differentiation of porcine and guinea pig enteric ganglia exposed to lipopolysaccharide (LPS).

METHODS

Primary cultures of enteric ganglia were obtained by mechanic and enzymatic digestion of ileum resections from guinea pigs (Cavia porcellus) (GPEG) and pigs (Suus scrofa) (PEG). pVW-MSCs were derived by enzymatic digestion from vascular wall resections of porcine aorta and tested by immunoflowcytometry for MSC immune profile. Enteric ganglia were treated with increasing concentrations of LPS, CM derived by pVW-MSCs or a combination of CM and LPS 1 µg/mL. Cell count and morphometric analysis of HuD positive neurons and glial fibrillary acidic protein positive glial cells were performed by immunofluorecent staining of cultured ganglia.

RESULTS

PEG showed a higher number of neurons compared to GPEG. Overall, CM exerted a protective role on LPS-treated enteric ganglia. CM in combination with LPS increased the number of glial cells per ganglion in both cultures evoking glial cells differentiation in porcine cultures.

CONCLUSION

These findings suggest an immunomodulating activity of pVW-MSCs mediators on the enteric nervous system in inflammatory conditions.

Mesenchymal Stem Cells and Induced Bone Marrow-Derived Macrophages Synergistically Improve Liver Fibrosis in Mice

We describe a novel therapeutic approach for cirrhosis using mesenchymal stem cells (MSCs) and colony-stimulating factor-1-induced bone marrow-derived macrophages (id-BMMs) and analyze the mechanisms underlying fibrosis improvement and regeneration. Mouse MSCs and id-BMMs were cultured from mouse bone marrow and their interactions analyzed in vitro. MSCs, id-BMMs, and a combination therapy using MSCs and id-BMMs were administered to mice with CCl₄ -induced cirrhosis. Fibrosis regression, liver regeneration, and liver-migrating host cells were evaluated. Administered cell behavior was also tracked by intravital imaging. In coculture, MSCs induced switching of id-BMMs toward the M2 phenotype with high phagocytic activity. In vivo, the combination therapy reduced liver fibrosis (associated with increased matrix metalloproteinases expression), increased hepatocyte proliferation (associated with increased hepatocyte growth factor, vascular endothelial growth factor, and oncostatin M in the liver), and reduced blood levels of liver enzymes, more effectively than MSCs or id-BMMs monotherapy. Intravital imaging showed that after combination cell administration, a large number of id-BMMs, which phagocytosed hepatocyte debris and were retained in the liver for more than 7 days, along with a few MSCs, the majority of which were trapped in the lung, migrated to the fibrotic area in the liver. Host macrophages and neutrophils infiltrated after combination therapy and contributed to liver fibrosis regression and promoted regeneration along with administered cells. Indirect effector MSCs and direct effector id-BMMs synergistically improved cirrhosis along with host cells in mice. These studies pave the way for new treatments for cirrhosis. Stem Cells Translational Medicine 2019;8:271&284.

Early injection of human adipose tissue-derived mesenchymal stem cell after inflammation ameliorates dextran sulfate sodium-induced colitis in mice through the induction of M2 macrophages and regulatory T cells

Inflammatory bowel diseases (IBDs) are sometimes refractory to current therapy or associated with severe adverse events during immunosuppressive therapy; thus, new therapies are urgently needed. Recently, mesenchymal stem cells (MSCs) have attracted attention based on their multitude of functions including anti-inflammatory effects. However, proper timing of MSC therapy and the mechanisms underlying the therapeutic effects of MSCs on colitis are not fully elucidated. Human adipose tissue-derived mesenchymal stem cells (hAdMSCs; 1 × 10⁶) were administrated via the tail vein on day 3 (early) or 11 (delayed) using a 7-day dextran sulfate sodium (DSS)-induced mouse model of colitis. The effects were evaluated based on colon length, disease activity index (DAI) and histological score. Cytokine-encoding mRNA levels T cells and macrophages were evaluated by real-time PCR and flow cytometry. Regarding the timing of administration, early (day 3) injection significantly ameliorated DSS-induced colitis in terms of both DAI and histological score, compared to those parameters with delayed (day 11) injection. With early cell injection, the tissue mRNA levels of anti-inflammatory cytokine genes (Il10, Tgfb) increased, whereas those of inflammatory cytokine genes (Il6, Tnfa and Il17a) decreased significantly. Regarding the associated mechanism, hAdMSCs suppressed T cell proliferation and activation in vitro, increased the number of regulatory T cells in vivo and changed the polarity of macrophages (into the anti-inflammatory M2 phenotype) in vitro. Timing of injection is critical for the effective therapeutic effects of hAdMSCs. Furthermore, part of the associated mechanism includes T cell activation and expansion and altered macrophage polarization.

Transcriptional response to Wnt activation regulates the regenerative capacity of the mammalian cochlea

Lack of sensory hair cell (HC) regeneration in mammalian adults is a major contributor to hearing loss. In contrast, the neonatal mouse cochlea retains a transient capacity for regeneration, and forced Wnt activation in neonatal stages promotes supporting cell (SC) proliferation and induction of ectopic HCs. We currently know little about the temporal pattern and underlying mechanism of this age-dependent regenerative response. Using an in vitro model, we show that Wnt activation promotes SC proliferation following birth, but prior to postnatal day (P) 5. This age-dependent decline in proliferation occurs despite evidence that the Wnt pathway is postnatally active and can be further enhanced by Wnt stimulators. Using an in vivo mouse model and RNA sequencing, we show that proliferation in the early neonatal cochlea is correlated with a unique transcriptional response that diminishes with age. Furthermore, we find that augmenting Wnt signaling through the neonatal stages extends the window for HC induction in response to Notch signaling inhibition. Our results suggest that the downstream transcriptional response to Wnt activation, in part, underlies the regenerative capacity of the mammalian cochlea.

Summary: Canonical Wnt activation in the mammalian cochlea elicits a unique, age-dependent transcriptional response, which in part regulates the regenerative capacity of supporting cells during cochlear maturation.

LincRNA-p21 promotes mesenchymal stem cell migration capacity and survival through hypoxic preconditioning

Background

Mesenchymal stem cells (MSCs) derived from bone marrow have potent stabilizing effects for the treatment of acute respiratory distress syndrome (ARDS). However, low efficiency and survival in MSC homing to injured lung tissue remains to be solved. Therefore, the aim of this study was to assess whether large intergenic noncoding RNA (LincRNA)-p21 promote MSC migration and survival capacity through hypoxic preconditioning in vitro.

Methods

MSCs were cultured and divided into the normoxia culture group (20% O2) and hypoxia culture group (1% O2). To determine roles and mechanisms, lentivirus vector-mediated LincRNA-p21 knockdown of MSCs and hypoxia-inducible factor (HIF-1α) inhibitor KC7F2 were introduced. Additionally, MSC migration was analyzed by scratch test and transwell migration assays. MSC proliferation was tested by cell counting kit-8 and trypan blue dye. Apoptosis was detected by Annexin V-PE/7-AAD stained flow cytometry. Moreover, LincRNA-p21 and HIF-1α mRNA was measured by reverse transcription-polymerase chain reaction, and HIF-1α and CXCR4/7 protein were assayed by western blot (WB) or enzyme-linked immunosorbent assay (ELISA). Apoptosis protein caspase-3 and cleaved-caspase-3 were investigated by WB analysis. Considering interactions between VHL and HIF-1α under LincRNA-p21 effect, co-immunoprecipitation was detected.

Results

Hypoxic preconditioning MSC promoted migration capacity and MSC survival than normoxia culture group. MSCs induced by hypoxic preconditioning evoked an increase in expression of LincRNA-p21, HIF-1α, and CXCR4/7(both were chemokine stromal-derived factor-1(SDF-1) receptors). Contrarily, blockade of LincRNA-p21 by shRNA and HIF-1α inhibitor KC7F2 abrogated upregulation of hypoxic preconditioning induced CXCR4/7 in MSCs, cell migration, and survival. Furthermore, co-immunoprecipitation assay revealed that hypoxic preconditioning isolated VHL and HIF-1α protein by increasing HIF-1α expression.

Conclusions

Hypoxic preconditioning was identified as a promoting factor of MSC migration and survival capacity. LincRNA-p21 promotes MSC migration and survival capacity through HIF-1α/CXCR4 and CXCR7 pathway under hypoxic preconditioning in vitro.

Improvement of Cell Cycle Lifespan and Genetic Damage Susceptibility of Human Mesenchymal Stem Cells by Hypoxic Priming

Hypoxic culture is widely recognized as a method to efficiently expand human mesenchymal stem cells (MSCs) without loss of stem cell properties. However, the molecular basis of how hypoxia priming benefits MSC expansion remains unclear. We report that hypoxic priming markedly extends the cell cycle lifespan rather than augmenting the multipotency of MSC differentiation lineage. Hypoxic priming does not affect to chromosome damage but significantly attenuates the susceptibility of chromosome damage. Our results provide important evidence that multipotency of human MSCs by hypoxic priming is determined by cell cycle lifespan.

The immunomodulatory effects of adipose-derived mesenchymal stem cells and mesenchymal stem cells-conditioned medium in chronic colitis

Inflammatory bowel disease (IBD) as a chronic recurrent disorder is characterized by mucosal immune response dysregulation, which is more prevalent in the youth. Adipose-derived mesenchymal stem cells (ADMSCs) are the multipotent cells that can be effective in immune response regulation via cell-cell interaction and their secretions. In this study, the effects of ADMSCs and mesenchymal stem cell-conditioned medium (MSC-CM) were evaluated on dextran sulfate sodium (DSS)-induced colitis in mice. Chronic colitis was induced in female C57BL/6 mice using 2% DSS in drinking water for three cycles; there were 4 days of DSS-water administration that was followed by 7 days of DSS-free water, in a cycle. ADMSCs, 10⁶ cells per mouse, were injected intraperitoneally (IP), whereas the MSC-CM injection was also performed six times from the last day of DSS in Cycle 1. Clinical symptoms were recorded daily. The colon pathological changes, cytokine levels, and regulatory T (Treg) cell percentages were then analyzed. After receiving ADMSCs and MSC-CM in colitis mice, the clinical symptoms and disease activity index were improved and the survival rate was increased. The histopathological examination also showed tissue healing in comparison with the nontreated group. In addition, the increased level of transforming growth factor beta, increased percentage of Treg cells, increased level of interleukin (IL)-10, and decreased level of IL-17 were observed after the treatment. This study showed the regulatory effects of ADMSCs and MSC-CM on inflammatory responses. Therefore, the use of ADMSCs and MSC-CM can be introduced as a new and effective therapeutic approach for patients with colitis.

Treatment of experimental colitis by endometrial regenerative cells through regulation of B lymphocytes in mice

BACKGROUND

Endometrial regenerative cells (ERCs), a novel type of mesenchymal-like stem cell derived from menstrual blood, have been recently evaluated as an attractive candidate source in ulcerative colitis (UC); however, the mechanism is not fully understood. The present study was designed to investigate the effects of ERCs, especially on B-cell responses in UC.

METHODS

In this study, colitis was induced by administering 3% dextran sodium sulfate (DSS) via free drinking water for 7 days to BALB/c mice. In the treated group, mice were injected intravenously with 1 × 10⁶ ERCs on days 2, 5, and 8 after DSS induction. Therapeutic effects were assessed by monitoring body weight, disease activity, and pathological changes. Subpopulations of lymphocytes were determined by flow cytometry. IgG deposition in the colon was examined by immunohistochemistry staining. Cytokine levels were measured by enzyme-linked immunosorbent assay (ELISA), Western blot, or polymerase chain reaction (PCR) analysis. Adoptive transfer of regulatory B cells (Bregs) into colitis mice was performed.

RESULTS

Here, we demonstrated that ERC treatment prolonged the survival of colitis mice and attenuated disease activity with fewer pathological changes in colon tissue. ERCs decreased the proportion of immature plasma cells in the spleen and IgG deposition in the colon. On the other hand, ERCs increased the production of Bregs and the interleukin (IL)-10 level. Additionally, adoptive transferred Bregs exhibited significant therapeutic effects on colitis mice.

CONCLUSIONS

In conclusion, our results unravel the therapeutic role of ERCs on experimental colitis through regulating the B-lymphocyte responses.

Mesenchymal stem cell therapy for acute and chronic pancreatitis

Mesenchymal stem cells (MSCs) have attracted attention as a cell source for regenerative medicine. In particular, MSCs have an anti-inflammatory effect by secreting several kinds of bioactive molecules. MSC therapy is now being applied to various gastrointestinal diseases, such as graft-versus-host disease, inflammatory bowel disease, and liver cirrhosis. Therefore, MSC therapy has the potential to be a novel treatment for acute and chronic pancreatitis by suppressing inflammation. Several studies have investigated the effect of MSC therapy on acute and chronic pancreatitis, but the underlying mechanisms remain unknown. In this review, we summarize the present status of MSC therapy for acute and chronic pancreatitis.

Study the effects of mesenchymal stem cell conditioned medium injection in mouse model of acute colitis

BACKGROUND AND AIM

Inflammatory bowel disease (IBD) is an autoimmune-inflammatory disorder that results in inflammatory responses in individuals who are genetically susceptible. Uncontrolled inflammation in Crohn's disease (CD) or Ulcerative colitis (UC) affects the patient quality of life. Current therapies are not completely effective while cell therapy, especially the treatment with mesenchymal stem cells (MSCs) absorb lots of attention due to its immunomodulatory properties. So, we examined the effects of mesenchymal stem cells-conditioned medium (MSC-CM) in the experimental model of acute colitis.

MATERIAL AND METHOD

MSC-CM was isolated from C57Bl/6 male mice and stored. The acute colitis induction in C57BL/6 mice was performed by dissolving dextran sulfate sodium (DSS) in drinking water and then CM injected intraperitoneally. During the study body weight changes, bleeding, stool consistency, disease activity index (DAI), mortality rate, weight and length of the colon and histopathological analysis were recorded as well as changes in the percentage of Treg cells. The level of IL-17, IL-10, and TGF-β were measured, too. Data were reported as mean±SD and analyzed by One-Way ANOVA test.

RESULTS

Based on the results it is recognized CM inhibited the weight loss and bleeding and improved fecal consistency and DAI. Macroscopic examination of the colon showed that after infusion, colon inflammation was reduced and histopathological analysis showed a decrease in mucosal degeneration. The percentage of Treg cells, secretion of IL-10 and TGF-β was increased while the IL-17 level was reduced.

CONCLUSION

This study showed that mesenchymal stem cell secretion with immunomodulatory properties has the potential to reduce inflammatory responses.

Mesenchymal stem cell transplantation for treatment of pancreatitis

Mesenchymal stem cells (MSCs) are one of the main cell resources of regenerative medicine. Recently, MSCs have been used to treat many diseases, such as Alzheimer's disease, inflammatory bowel disease and cirrhosis, with certain curative effects achieved. MSCs can not only secrete a variety of anti-inflammatory cytokines, but also reduce the secretion of inflammatory factors. Therefore, acute pancreatitis (AP) and chronic pancreatitis (CP) can be treated with MSCs. Several studies have investigated the effect of MSC therapy on acute and CP. MSCs exert a therapeutic effect on AP perhaps via two pathways: anti-inflammatory pathway and anti-apoptotic pathway. However, the mechanism for the therapeutic effect of MSCs on CP is unclear. In this review, we will summarize the progress in MSC treatment of AP and CP.

Therapeutic Potential of Secreted Molecules Derived from Human Amniotic Fluid Mesenchymal Stem/Stroma Cells in a Mice Model of Colitis

Inflammatory bowel diseases (IBDs) are the result of pathological immune responses due to environmental factors or microbial antigens into a genetically predisposed individual. Mainly due to their trophic properties, a mounting interest is focused on the use of human mesenchymal stem/stromal cells (hMSCs) to treat IBD disease in animal models. The aim of the study is to test whether the secreted molecules, derived from a specific population of second trimester amniotic fluid mesenchymal stem/stromal cells, the spindle-shaped MSCs (SS-AF-MSCs), could be utilized as a novel therapeutic, cell free approach for IBD therapy. Induction of colitis was achieved by oral administration of dextran sulphate sodium (DSS) (3 % w/v in tap water), for 5 days, to 8-week-old NOD/SCID mice. The progression of colitis was assessed on a daily basis through recording the body weight, stool consistency and bleeding. Conditioned media (CM) derived from SS-AF-MSCs were collected, concentrated and then delivered intraperitoneally into DSS treated mice. To evaluate and determine the inflammatory cytokine levels, histopathological approach was applied. Administration of CM derived from SS-AF-MSCs cells reduced the severity of colitis in mice. More importantly, TGFb1 protein levels were increased in the mice received CM, while TNFa and MMP2 protein levels were decreased, respectively. Accordingly, IL-10 was significantly increased in mice received CM, whereas TNFa and IL-1b were decreased at mRNA level. Our results demonstrated that CM derived from SS-AF-MSCs cells is able to ameliorate DSS-induced colitis in immunodeficient colitis mouse model, and thus, it has a potential for use in IBD therapy.

Secretome from hypoxia-conditioned adipose-derived mesenchymal stem cells promotes the healing of gastric mucosal injury in a rodent model

Studies have indicated that the definitive engraftment and transdifferentiation potential of stem cells do not seem crucial for its property of tissue repair. Our previous study showed that transplantation of adipose-derived mesenchymal stem cells (ADMSCs) enhanced the healing of sutured gastric perforation. This study aimed to investigate the paracrine role of ADMSCs in the experimental gastric mucosal injury. Normoxia-conditioned medium (Nor CM) and hypoxia (HPO) CM were obtained after culturing ADMSCs in 20% O₂ and 5% O₂ for 48h. Cell migration, proliferation, viability, and angiogenesis in vitro were significantly enhanced upon incubation with CM, especially the HPO CM. Experiments in vivo using a rodent model of gastric ulcer demonstrated that HPO CM treatment significantly accelerated wound healing by suppressing inflammation and promoting neovascularization and re-epithelization. Meanwhile, the infusion of HPO CM activated the COX₂-PGE₂ axis both in vitro and in vivo. And the upregulation of COX₂ was further dependent on the activation of ErK1/2-MAPK pathway. In addition, vascular endothelial growth factor, tissue inhibitors of metalloproteinases-1, and chemokine (C-C motif) ligand 20 (CCL-20) were analyzed as being highly abundant factors secreted by ADMSCs under hypoxic condition. Notably, the blockade of CCL-20 abrogated the HPO CM-induced COX₂ signaling in the primary gastric mucosal epithelial cells, while incubation with recombinant CCL-20 increased the expression of COX₂. In conclusion, the secretome from hypoxia-conditioned ADMSCs facilitates the repair of gastric mucosal injury through the enhancement of angiogenesis and re-epithelization, as well as the activation of COX₂-PGE₂ axis with a paracrine activity involving CCL-20 factor.

Crosstalk between mesenchymal stem cells and macrophages in inflammatory bowel disease and associated colorectal cancer

Mesenchymal stem cells (MSCs) are attractive seed cells for immunotherapy, tissue engineering and regenerative medicine due to their self-renewal and multidirectional differentiation abilities, diverse immunoregulatory functions and ease of isolation from a wide range of tissues. MSCs exert their immunoregulatory effect on immune cells via cell-to-cell contact and paracrine mechanisms. In turn, MSCs can also be modulated by immune cells. Macrophages are constantly present in the mucosa of the intestinal tract of mammals and play an important role in the development and progression of inflammatory bowel disease (IBD), a chronic and recurrent inflammatory disease of the gastrointestinal tract characterized by idiopathic mucosal inflammation. The increased morbidity and mortality of IBD have made it a disease hard to cure in the clinic. MSCs have emerged as an important tool for IBD therapy due to their abilities to differentiate into enterocyte-like cells and regulate inflammatory cells, especially macrophages. In this review, we discuss the recent advances in the interaction between MSCs and macrophages in diseases, with an emphasis on IBD. We propose that an optimized MSC-based therapy would provide a novel strategy for the treatment of IBD and the prevention of IBD-associated colorectal cancer (CRC).

Exosomes Derived from Human Umbilical Cord Mesenchymal Stem Cells Relieve Inflammatory Bowel Disease in Mice

Exosomes secreted by mesenchymal stem cells (MSCs) have shown repairing effects on several tissue injury diseases. In this study, we aimed to investigate the effects of exosomes released from human umbilical cord mesenchymal stem cells (hucMSCs) on the treatment of dextran sulfate sodium- (DSS-) induced inflammatory bowel disease (IBD) and to explore the underlying mechanism. We found that indocyanine green (ICG) labeled exosomes homed to colon tissues of IBD mice at 12 hours after injection. Exosomes significantly relieved the severity of IBD in mice as hucMSCs. The expression of IL-10 gene was increased while that of TNF-α, IL-1β, IL-6, iNOS, and IL-7 genes was decreased in the colon tissues and spleens of exosomes-treated mice. Furthermore, the infiltration of macrophages into the colon tissues was decreased by exosome treatment in IBD mice. In addition, we provided evidence that in vitro coculture with exosomes inhibited the expression of iNOS and IL-7 in mouse enterocoelia macrophages. Moreover, we found that the expression of IL-7 was higher in the colon tissues of colitis patients than that of healthy controls. Our findings suggest that exosomes from hucMSCs have profound effects on alleviating DSS-induced IBD and may exert their impact through the modulation of IL-7 expression in macrophages.

Conditioned Medium from Periodontal Ligament Stem Cells Enhances Periodontal Regeneration

Periodontal disease is one of the most common infectious diseases in adults and is characterized by the destruction of tooth-supporting tissues. Mesenchymal stem cells (MSCs) comprise the mesoderm-originating stem cell population, which has been studied and used for cell therapy. However, because of the lower rate of cell survival after MSC transplantation in various disease models, paracrine functions of MSCs have been receiving increased attention as a regenerative mechanism. The aim of this study was to investigate the regenerative potential of transplanted conditioned medium (CM) obtained from cultured periodontal ligament stem cells (PDLSCs), the adult stem cell population in tooth-supporting tissues, using a rat periodontal defect model. Cell-free CM was collected from PDLSCs and fibroblasts, using ultrafiltration and transplanted into surgically created periodontal defects. Protein content of CM was examined by antibody arrays. Formation of new periodontal tissues was analyzed using microcomputed tomography and histological sections. PDLSC-CM transplantation enhanced periodontal tissue regeneration in a concentration-dependent manner, whereas fibroblast-CM did not show any regenerative function. Proteomic analysis revealed that extracellular matrix proteins, enzymes, angiogenic factors, growth factors and cytokines were contained in PDLSC-CM. Furthermore, PDLSC-CM transplantation resulted in the decreased mRNA level of tumor necrosis factor-α (TNF-α) in healing periodontal tissues. In addition, we found that PDLSC-CM suppressed the mRNA level of TNF-α in the monocyte/macrophage cell line, RAW cells, stimulated with IFN-γ. Our findings suggested that PDLSC-CM enhanced periodontal regeneration by suppressing the inflammatory response through TNF-α production, and transplantation of PDLSC-CM could be a novel approach for periodontal regenerative therapy.

Antioxidant properties of mesenchymal stem cells against oxidative stress in a murine model of colitis

OBJECTIVE

To investigate the effects of oxidative stress injury in dextran sulfate sodium (DSS)-induced colitis in mice treated with mesenchymal stem cells (MSC).

RESULTS

Mice exposed to oral administration of 2% DSS over 7 days presented a high disease activity index and an intense colonic inflammation. Systemic infusion of MSC protected from severe colitis, reducing weight loss and diarrhea while lowering the infiltration of inflammatory cells. Moreover, toxic colitis injury increased oxidative stress. Administration of DSS decreased reduced glutathione (GSH) and superoxide dismutase (SOD) activity, and increased thiobarbituric acid-reactive substances levels in the colon. No alteration was found in catalase (CAT) and glutathione peroxidase (GPx) activity. Otherwise, MSC transplantation was able to prevent the decrease of GSH levels and SOD activity suggestive of an antioxidant property of MSC.

CONCLUSION

The oxidative stress is a pathomechanism underlying the pathophysiology of colitis and MSC play an important role in preventing the impairment of antioxidants defenses in inflamed colon.

Mesenchymal stromal cell-based therapy: Regulatory and translational aspects in gastroenterology

The past decade has witnessed an outstanding scientific production focused towards the possible clinical applications of mesenchymal stromal cells (MSCs) in autoimmune and chronic inflammatory diseases. This raised the need of novel standards to adequately address quality, efficacy and safety issues of this advanced therapy. The development of a streamlined regulation is currently hampered by the complexity of analyzing dynamic biological entities rather than chemicals. Although numerous pieces of evidence show efficacy in reducing intestinal inflammation, some inconsistencies between the mechanisms of action of rodent vs human MSCs suggest caution before assigning translational value to preclinical studies. Preliminary evidence from clinical trials showed efficacy of MSCs in the treatment of fistulizing Crohn’s disease (CD), and preparations of heterologous MSCs for CD treatment are currently tested in ongoing clinical trials. However, safety issues, especially in long-term treatment, still require solid clinical data. In this regard, standardized guidelines for appropriate dosing and methods of infusion could enhance the likelihood to predict more accurately the number of responders and the duration of remission periods. In addition, elucidating MSC mechanisms of action could lead to novel and more reliable formulations such as those derived from the MSCs themselves (e.g., supernatants).

Mesenchymal stem cell therapy ameliorates diabetic nephropathy via the paracrine effect of renal trophic factors including exosomes

Bone marrow-derived mesenchymal stem cells (MSCs) have contributed to the improvement of diabetic nephropathy (DN); however, the actual mediator of this effect and its role has not been characterized thoroughly. We investigated the effects of MSC therapy on DN, focusing on the paracrine effect of renal trophic factors, including exosomes secreted by MSCs. MSCs and MSC-conditioned medium (MSC-CM) as renal trophic factors were administered in parallel to high-fat diet (HFD)-induced type 2 diabetic mice and streptozotocin (STZ)-induced insulin-deficient diabetic mice. Both therapies showed approximately equivalent curative effects, as each inhibited the exacerbation of albuminuria. They also suppressed the excessive infiltration of BMDCs into the kidney by regulating the expression of the adhesion molecule ICAM-1. Proinflammatory cytokine expression (e.g., TNF-α) and fibrosis in tubular interstitium were inhibited. TGF-β1 expression was down-regulated and tight junction protein expression (e.g., ZO-1) was maintained, which sequentially suppressed the epithelial-to-mesenchymal transition of tubular epithelial cells (TECs). Exosomes purified from MSC-CM exerted an anti-apoptotic effect and protected tight junction structure in TECs. The increase of glomerular mesangium substrate was inhibited in HFD-diabetic mice. MSC therapy is a promising tool to prevent DN via the paracrine effect of renal trophic factors including exosomes due to its multifactorial action.

Flagellin preconditioning enhances the efficacy of mesenchymal stem cells in an irradiation-induced proctitis model

The success of mesenchymal stem cell transplantation for proctitis depends not only on cell donors but also on host microenvironmental factors, which play a major role in conditioning mesenchymal stem cell immunosuppressive action and repair. This study sought to determine if flagellin, a TLR5 ligand, can enhance the mesenchymal stem cell treatment efficacy in radiation-induced proctitis. With the use of a colorectal model of 27 Gy irradiation in rats, we investigated and compared the effects on immune capacity and remodeling at 28 d after irradiation of the following: 1) systemic mesenchymal stem cell (5 × 10(6)) administration at d 7 after irradiation, 2) administration of flagellin at d 3 and systemic mesenchymal stem cell administration at d 7, and 3) in vitro preconditioning of mesenchymal stem cells with flagellin, 24 h before their administration on d 7. The mucosal CD8(+) T cell population was normalized after treatment with flagellin-preconditioned mesenchymal stem cells or flagellin plus mesenchymal stem cells, whereas mesenchymal stem cells alone did not alter the radiation-induced elevation of CD8(+) T cell frequency. Mesenchymal stem cell treatment returned the irradiation-elevated frequency of CD25(+) cells in the mucosa-to-control levels, whereas both flagellin-preconditioned mesenchymal stem cell and flagellin-plus-mesenchymal stem cell treatment each significantly increased not only CD25(+) cell frequency but also forkhead box p3 and IL-2Rα expression. Specifically, IL-10 was overexpressed after flagellin-preconditioned mesenchymal stem cell treatment. Analysis of collagen expression showed that the collagen type 1/collagen type 3 ratio, an indicator of wound-healing maturation, was low in the irradiated and mesenchymal stem cell-treated groups and returned to the normal level only after the flagellin-preconditioned mesenchymal stem cell treatment. This was associated with a reduction in myofibroblast accumulation. In a proctitis model, flagellin-preconditioned mesenchymal stem cells improved colonic immune capacity and enhanced tissue remodeling.

Mucosally transplanted mesenchymal stem cells stimulate intestinal healing by promoting angiogenesis

Mesenchymal stem cell (MSC) therapy is an emerging field of regenerative medicine; however, it is often unclear how these cells mediate repair. Here, we investigated the use of MSCs in the treatment of intestinal disease and modeled abnormal repair by creating focal wounds in the colonic mucosa of prostaglandin-deficient mice. These wounds developed into ulcers that infiltrated the outer intestinal wall. We determined that penetrating ulcer formation in this model resulted from increased hypoxia and smooth muscle wall necrosis. Prostaglandin I₂ (PGI₂) stimulated VEGF-dependent angiogenesis to prevent penetrating ulcers. Treatment of mucosally injured WT mice with a VEGFR inhibitor resulted in the development of penetrating ulcers, further demonstrating that VEGF is critical for mucosal repair. We next used this model to address the role of transplanted colonic MSCs (cMSCs) in intestinal repair. Compared with intravenously injected cMSCs, mucosally injected cMSCs more effectively prevented the development of penetrating ulcers, as they were more efficiently recruited to colonic wounds. Importantly, mucosally injected cMSCs stimulated angiogenesis in a VEGF-dependent manner. Together, our results reveal that penetrating ulcer formation results from a reduction of local angiogenesis and targeted injection of MSCs can optimize transplantation therapy. Moreover, local MSC injection has potential for treating diseases with features of abnormal angiogenesis and repair.

Mesenchymal Stem Cells Reduce Colitis in Mice via Release of TSG6, Independently of Their Localization to the Intestine

BACKGROUND & AIMS

Mesenchymal stem cells (MSCs) are pluripotent cells that can promote expansion of immune regulatory cells and might be developed for the treatment of immune disorders, including inflammatory bowel diseases. MSCs were reported to reduce colitis in mice; we investigated whether MSC localization to the intestine and production of paracrine factors, including tumor necrosis factor-induced protein 6 (TSG6), were required for these effects.

METHODS

MSCs were isolated from bone marrow (BM-MSCs) of 4- to 6-week-old C57BL/6, C57BL/6-green fluorescent protein, or Balb/c Tsg6-/- male mice. Colitis was induced by ad libitum administration of dextran sulfate sodium for 10 days; after 5 days the mice were given intraperitoneal injections of BM-MSCs or saline (controls). Blood samples and intestinal tissues were collected 24, 48, 96, and 120 hours later; histologic and flow cytometry analyses were performed.

RESULTS

Injection of BM-MSCs reduced colitis in mice, increasing body weight and reducing markers of intestinal inflammation, compared with control mice. However, fewer than 1% of MSCs reached the inflamed colon. Most of the BM-MSCs formed aggregates in the peritoneal cavity. The aggregates contained macrophages and B and T cells, and produced immune-regulatory molecules including FOXP3, interleukin (IL)10, transforming growth factor-β, arginase type II, chemokine (C-C motif) ligand 22 (CCL22), heme oxygenase-1, and TSG6. Serum from mice given BM-MSCs, compared with mice given saline, had increased levels of TSG6. Injection of TSG6 reduced the severity of colitis in mice, along with the numbers of CD45+ cells, neutrophils and metalloproteinase activity in the mucosa, while increasing the percentage of Foxp3CD45+ cells. TSG6 injection also promoted the expansion of regulatory macrophages that expressed IL10 and inducible nitric oxide synthase, and reduced serum levels of interferon-γ, IL6, and tumor necrosis factor. Tsg6-/- MSCs did not suppress the mucosal inflammatory response in mice with colitis.

CONCLUSIONS

BM-MSCs injected into mice with colitis do not localize to the intestine but instead form aggregates in the peritoneum where they produce immunoregulatory molecules, including TSG6, that reduce intestinal inflammation. TSG6 is sufficient to reduce intestinal inflammation in mice with colitis.

Hypoxia-preconditioned mesenchymal stem cells attenuate bleomycin-induced pulmonary fibrosis

INTRODUCTION

Idiopathic pulmonary fibrosis is a progressive diffuse parenchymal lung disorder of unknown etiology. Mesenchymal stem cell (MSC)-based therapy is a novel approach with great therapeutic potential for the treatment of lung diseases. Despite demonstration of MSC grafting, the populations of engrafted MSCs have been shown to decrease dramatically 24 hours post-transplantation due to exposure to harsh microenvironments. Hypoxia is known to induce expression of cytoprotective genes and also secretion of anti-inflammatory, anti-apoptotic and anti-fibrotic factors. Hypoxic preconditioning is thought to enhance the therapeutic potency and duration of survival of engrafted MSCs. In this work, we aimed to prolong the duration of survival of engrafted MSCs and to enhance the effectiveness of idiopathic pulmonary fibrosis transplantation therapy by the use of hypoxia-preconditioned MSCs.

METHODS

Hypoxic preconditioning was achieved in MSCs under an optimal hypoxic environment. The expression levels of cytoprotective factors and their biological effects on damaged alveolar epithelial cells or transforming growth factor-beta 1-treated fibroblast cells were studied in co-culture experiments in vitro. Furthermore, hypoxia-preconditioned MSCs (HP-MSCs) were intratracheally instilled into bleomycin-induced pulmonary fibrosis mice at day 3, and lung functions, cellular, molecular and pathological changes were assessed at 7 and 21 days after bleomycin administration.

RESULTS

The expression of genes for pro-survival, anti-apoptotic, anti-oxidant and growth factors was upregulated in MSCs under hypoxic conditions. In transforming growth factor-beta 1-treated MRC-5 fibroblast cells, hypoxia-preconditioned MSCs attenuated extracellular matrix production through paracrine effects. The pulmonary respiratory functions significantly improved for up to 18 days of hypoxia-preconditioned MSC treatment. Expression of inflammatory factors and fibrotic factor were all downregulated in the lung tissues of the hypoxia-preconditioned MSC-treated mice. Histopathologic examination observed a significant amelioration of the lung fibrosis. Several LacZ-labeled MSCs were observed within the lungs in the hypoxia-preconditioned MSC treatment groups at day 21, but no signals were detected in the normoxic MSC group. Our data further demonstrated that upregulation of hepatocyte growth factor possibly played an important role in mediating the therapeutic effects of transplanted hypoxia-preconditioned MSCs.

CONCLUSION

Transplantation of hypoxia-preconditioned MSCs exerted better therapeutic effects in bleomycin-induced pulmonary fibrotic mice and enhanced the survival rate of engrafted MSCs, partially due to the upregulation of hepatocyte growth factor.