Human umbilical cord mesenchymal stem cells ameliorate mice trinitrobenzene sulfonic acid (TNBS)-induced colitis

Mesenteric lymph nodes: a critical site for the up-regulatory effect of hUC-MSCs on Treg cells by producing TGF-β1 in colitis treatment

BACKGROUND

Mesenchymal stem cells (MSCs) demonstrate a wide range of therapeutic capabilities in the treatment of inflammatory bowel disease (IBD). The intraperitoneal injection of MSCs has exhibited superior therapeutic efficacy on IBD than intravenous injection. Nevertheless, the precise in vivo distribution of MSCs and their biological consequences following intraperitoneal injection remain inadequately understood. Additional studies are required to explore the correlation between MSCs distribution and their biological effects.

METHODS

First, the distribution of human umbilical cord MSCs (hUC-MSCs) and the numbers of Treg and Th17 cells in mesenteric lymph nodes (MLNs) were analyzed after intraperitoneal injection of hUC-MSCs. Subsequently, the investigation focused on the levels of transforming growth factor beta1 (TGF-β1), a key cytokine to the biology of both Treg and Th17 cells, in tissues of mice with colitis, particularly in MLNs. The study also delved into the impact of hUC-MSCs therapy on Treg cell counts in MLNs, as well as the consequence of TGFB1 knockdown hUC-MSCs on the differentiation of Treg cells and the treatment of IBD.

RESULTS

The therapeutic effectiveness of intraperitoneally administered hUC-MSCs in the treatment of colitis was found to be significant, which was closely related to their quick migration to MLNs and secretion of TGF-β1. The abundance of hUC-MSCs in MLNs of colitis mice is much higher than that in other organs even the inflamed sites of colon. Intraperitoneal injection of hUC-MSCs led to a significant increase in the number of Treg cells and a decrease in Th17 cells especially in MLNs. Furthermore, the concentration of TGF-β1, the key cytokine for Treg differentiation, were also found to be significantly elevated in MLNs after hUC-MSCs treatment. Knockdown of TGFB1 in hUC-MSCs resulted in a noticeable reduction of Treg cells in MLNs and the eventually failure of hUC-MSCs therapy in colitis.

CONCLUSIONS

MLNs may be a critical site for the regulatory effect of hUC-MSCs on Treg/Th17 cells and the therapeutic effect on colitis. TGF-β1 derived from hUC-MSCs promotes local Treg differentiation in MLNs. This study will provide new ideas for the development of MSC-based therapeutic strategies in IBD patients.

Stem Cells and Stem Cell-Derived Factors for the Treatment of Inflammatory Bowel Disease with a Particular Focus on Perianal Fistulizing Disease: A Minireview on Future Perspectives

Inflammatory bowel disease remains a difficult disease to effectively treat, especially fistulizing Crohn's disease. Perianal fistulas in the setting of Crohn's disease remain an area of unmet need with significant morbidity in this patient population. Up to one third of Crohn's patients will have perianal fistulizing disease and current medical and surgical interventions are of limited efficacy. Thus, most patients experience significant morbidity, narcotic use, and loss of employment and end up with multiple surgical interventions. Mesenchymal stem cells (MSCs) have shown efficacy in phase 3 clinical trials, but considerable infrastructure challenges make MSCs limited with regard to scalability in clinical practice. Extracellular vesicles, being derived from MSCs and capturing the secretome functionality of MSCs, offer similar physiological utility regarding mechanism, while also providing an off the shelf regenerative medicine product that could be widely used in daily clinical practice.

Bone marrow-derived mesenchymal stem cells mitigate chronic colitis and enteric neuropathy via anti-inflammatory and anti-oxidative mechanisms

Current treatments for inflammatory bowel disease (IBD) are often inadequate due to limited efficacy and toxicity, leading to surgical resection in refractory cases. IBD's broad and complex pathogenesis involving the immune system, enteric nervous system, microbiome, and oxidative stress requires more effective therapeutic strategies. In this study, we investigated the therapeutic potential of bone marrow-derived mesenchymal stem cell (BM-MSC) treatments in spontaneous chronic colitis using the Winnie mouse model which closely replicates the presentation and inflammatory profile of ulcerative colitis. The 14-day BM-MSC treatment regimen reduced the severity of colitis, leading to the attenuation of diarrheal symptoms and recovery in body mass. Morphological and histological abnormalities in the colon were also alleviated. Transcriptomic analysis demonstrated that BM-MSC treatment led to alterations in gene expression profiles primarily downregulating genes related to inflammation, including pro-inflammatory cytokines, chemokines and other biomarkers of inflammation. Further evaluation of immune cell populations using immunohistochemistry revealed a reduction in leukocyte infiltration upon BM-MSC treatment. Notably, enteric neuronal gene signatures were the most impacted by BM-MSC treatment, which correlated with the restoration of neuronal density in the myenteric ganglia. Moreover, BM-MSCs exhibited neuroprotective effects against oxidative stress-induced neuronal loss through antioxidant mechanisms, including the reduction of mitochondrial-derived superoxide and attenuation of oxidative stress-induced HMGB1 translocation, potentially relying on MSC-derived SOD1. These findings suggest that BM-MSCs hold promise as a therapeutic intervention to mitigate chronic colitis by exerting anti-inflammatory effects and protecting the enteric nervous system from oxidative stress-induced damage.

Mesenchymal Stem Cells Versus Placebo for Perianal Fistulizing Crohn's Disease: A Systemic Review and Meta-Analysis

BACKGROUND

Mesenchymal stem cells (MSCs)-based therapy for perianal fistulizing Crohn's disease (pfCD) has been extensively studies in the past decade. Its efficacy and safety had been preliminarily confirmed in some phase 2 or phase 3 clinical trials. This meta-analysis is performed to evaluate the efficacy and safety of MSCs-based therapy for pfCD.

METHODS

Electronic databases (Pubmed, Cochrane Library, Embase) were searched for studies that reported the efficacy and safety of MSCs. And RevMan were used to assess the efficacy and safety.

RESULTS

After screening, 5 randomized controlled trials (RCTs) were included in this meta-analysis. RevMan 5.4 for meta-analysis showed that: [Efficacy] Patients had definite remission after MSCs treatment, with an odds ratio (OR) of 2.06 (P < .0001, 95%CI 1.46, 2.89) vs controls. [Safety] The incidence of the most frequently reported TEAEs (treatment-emergent adverse events, TEAEs), perianal abscess and proctalgia, did not significantly increase due to the use of MSCs, with an OR of 1.07 in perianal abscess (P = .87, 95%CI 0.67, 1.72) vs controls, and an OR of 1.10 in proctalgia (P = .47, 95%CI 0.63, 1.92) vs controls.

CONCLUSIONS

MSCs seem to be an effective and safe therapy for pfCD. MSCs based therapy has the potential to be used in combination with traditional therapies.

Bone marrow mesenchymal stem cells alleviate stress-induced hyperalgesia via restoring gut microbiota and inhibiting neuroinflammation in the spinal cord by targeting the AMPK/NF-κB signaling pathway

Aim Spinal neuroinflammation contributes to the mechanism of stress-induced hyperalgesia (SIH). Recent research has demonstrated that bone marrow mesenchymal stem cells (BMSCs) alleviate chronic pain. However, what remains unidentified is whether BMSCs could improve hyperalgesia induced by chronic restraint stress (CRS). In another dimension, our previous study proved that gut microbiota played an important role in CRS-induced hyperalgesia in mice. Yet, whether BMSCs treatments change gut microbiota composition in CRS mice remains unexplored.

MAIN METHODS

Mechanical allodynia and thermal hyperalgesia were used to assess pain behavior. Composition of fecal samples were verified by 16S rRNA analysis. Western blot was used to investigate the expression of adenosine monophosphate-activated protein kinase (AMPK)/ nuclear factor kappa B (NF-κB) signaling pathway, pro-inflammatory cytokines [interleukin-1 beta (IL-1β), tumor necrosis factor alpha (TNF-α), IL-6], and the markers of microglia and astrocytes. The morphology of glia cells was evaluated by immunofluorescence staining.

KEY FINDINGS

CRS down-regulated phosphorylated AMPK (p-AMPK), up-regulated phosphorylated NF-κB p65 (p-NF-κB p65), activated microglia and astrocytes and promoted the secretion of IL-1β, TNF-α and IL-6 in the spinal cord. BMSCs alleviated CRS-induced hyperalgesia by inhibiting the activation of microglia and astrocytes and by reducing neuroinflammation via improving the disrupted AMPK/NF-κB pathway. Furthermore, BMSCs also raised the relative abundance of Muribaculaceae and Lachnospiraceae in CRS mice feces, which was significantly related to its effect of relieving hyperalgesia.

SIGNIFICANCE

Our results support that BMSCs could alleviate CRS-induced hyperalgesia by reducing AMPK/NF-κB-dependent neuroinflammation in the spinal cord and restoring the homeostasis of gut microbiota.

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 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.

General consensus on multimodal functions and validation analysis of perinatal derivatives for regenerative medicine applications

Perinatal tissues, such as placenta and umbilical cord contain a variety of somatic stem cell types, spanning from the largely used hematopoietic stem and progenitor cells to the most recently described broadly multipotent epithelial and stromal cells. As perinatal derivatives (PnD), several of these cell types and related products provide an interesting regenerative potential for a variety of diseases. Within COST SPRINT Action, we continue our review series, revising and summarizing the modalities of action and proposed medical approaches using PnD products: cells, secretome, extracellular vesicles, and decellularized tissues. Focusing on the brain, bone, skeletal muscle, heart, intestinal, liver, and lung pathologies, we discuss the importance of potency testing in validating PnD therapeutics, and critically evaluate the concept of PnD application in the field of tissue regeneration. Hereby we aim to shed light on the actual therapeutic properties of PnD, with an open eye for future clinical application. This review is part of a quadrinomial series on functional/potency assays for validation of PnD, spanning biological functions, such as immunomodulation, anti-microbial/anti-cancer, anti-inflammation, wound healing, angiogenesis, and regeneration.

ADSCs stimulated by VEGF-C alleviate intestinal inflammation via dual mechanisms of enhancing lymphatic drainage by a VEGF-C/VEGFR-3-dependent mechanism and inhibiting the NF-κB pathway by the secretome

Background

Adipose-derived stem cells (ADSCs) have provided promising applications for Crohn’s disease (CD). However, the practical efficacy of ADSCs remains controversial, and their mechanism is still unclear. Based on the pathogenesis of dysregulated immune responses and abnormal lymphatic alterations in CD, vascular endothelial growth factor-C (VEGF-C) is thought to be a favourable growth factor to optimize ADSCs. We aimed to investigate the efficacy of VEGF-C-stimulated ADSCs and their dual mechanisms in both inhibiting inflammation “IN” and promoting inflammation “OUT” in the intestine.

Methods

Human stem cells isolated from adipose tissues were identified, pretreated with or without 100 ng/ml VEGF-C and analysed for the secretion of cell culture supernatants in vitro. Lymphatic endothelial cells (LECs) were treated with ADSCs-conditioned medium or co-cultured with ADSCs and VEGF-C stimulated ADSCs. Changes in LECs transmigration, and VEGF-C/VEGFR-3 mRNA levels were assessed by transwell chamber assay and qRT–PCR. ADSCs and VEGF-C-stimulated ADSCs were intraperitoneally injected into mice with TNBS-induced chronic colitis. ADSCs homing and lymphatic vessel density (LVD) were evaluated by immunofluorescence staining. Lymphatic drainage was assessed using Evans blue. Cytokines and growth factors expression was detected respectively by ELISA and qRT–PCR. The protein levels of VEGF-C/VEGFR-3-mediated downstream signals and the NF-κB pathway were assayed by western blot. Faecal microbiota was measured by 16S rRNA sequencing.

Results

ADSCs stimulated with VEGF-C released higher levels of growth factors (VEGF-C, TGF-β1, and FGF-2) and lower expression of cytokines (IFN-γ and IL-6) in cell supernatants than ADSCs in vitro (all P < 0.05). Secretome released by VEGF-C stimulated ADSCs exhibited a stronger LEC migratory capability and led to elevated VEGF-C/VEGFR-3 expression, but these effects were markedly attenuated by VEGFR-3 inhibitor. VEGF-C-stimulated ADSCs homing to the inflamed colon and mesenteric lymph nodes (MLNs) can exert stronger efficacy in improving colitis symptoms, reducing inflammatory cell infiltration, and significantly enhancing lymphatic drainage. The mRNA levels and protein concentrations of anti-inflammatory cytokines and growth factors were markedly increased with decreased proinflammatory cytokines in the mice treated with VEGF-C-stimulated ADSCs. Systemic administration of VEGF-C-stimulated ADSCs upregulated the colonic VEGF-C/VEGFR-3 pathway and activated downstream AKT and ERK phosphorylation signalling, accompanied by decreased NF-κB p65 expression. A higher abundance of faecal p-Bacteroidetes and lower p-Firmicutes were detected in mice treated with VEGF-C-stimulated ADSCs (all P < 0.05).

Conclusion

VEGF-C-stimulated ADSCs improve chronic intestinal inflammation by promoting lymphatic drainage and enhancing paracrine signalling via activation of VEGF-C/VEGFR-3-mediated signalling and inhibition of the NF-κB pathway. Our study may provide a new insight into optimizing ADSCs treatment and investigating potential mechanisms in CD.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-022-03132-3.

Efficacy and Safety of MSC Cell Therapies for Hospitalized Patients with COVID-19: A Systematic Review and Meta-Analysis

MSC (a.k.a. mesenchymal stem cell or medicinal signaling cell) cell therapies show promise in decreasing mortality in acute respiratory distress syndrome (ARDS) and suggest benefits in treatment of COVID-19-related ARDS. We performed a meta-analysis of published trials assessing the efficacy and adverse events (AE) rates of MSC cell therapy in individuals hospitalized for COVID-19. Systematic searches were performed in multiple databases through November 3, 2021. Reports in all languages, including randomized clinical trials (RCTs), non-randomized interventional trials, and uncontrolled trials, were included. Random effects model was used to pool outcomes from RCTs and non-randomized interventional trials. Outcome measures included all-cause mortality, serious adverse events (SAEs), AEs, pulmonary function, laboratory, and imaging findings. A total of 736 patients were identified from 34 studies, which included 5 RCTs (n = 235), 7 non-randomized interventional trials (n = 370), and 22 uncontrolled comparative trials (n = 131). Patients aged on average 59.4 years and 32.2% were women. When compared with the control group, MSC cell therapy was associated with a reduction in all-cause mortality (RR = 0.54, 95% CI: 0.35-0.85, I  2 = 0.0%), reduction in SAEs (IRR = 0.36, 95% CI: 0.14-0.90, I  2 = 0.0%) and no significant difference in AE rate. A sub-group with pulmonary function studies suggested improvement in patients receiving MSC. These findings support the potential for MSC cell therapy to decrease all-cause mortality, reduce SAEs, and improve pulmonary function compared with conventional care. Large-scale double-blinded, well-powered RCTs should be conducted to further explore these results.

Mesenchymal stem cell treatment for enteric neuropathy in the Winnie mouse model of spontaneous chronic colitis

Inflammatory bowel disease (IBD) is a chronic gut inflammation with periods of acute flares and remission. Beneficial effects of a single dose of mesenchymal stem cell (MSC)-based treatment have been demonstrated in acute models of colitis. No studies investigated therapeutic effects of MSCs for the attenuation of enteric neuropathy in a chronic model of colitis. The short and long-term effects of MSC treatment in modulating inflammation and damage to the enteric nervous system (ENS) were studied in the Winnie mouse model of spontaneous chronic colitis highly representative of human IBD. Winnie mice received a single dose of either 1 × 10⁶ human bone marrow-derived MSCs or 100µL PBS by intracolonic enema. C57BL/6 mice received 100µL PBS. Colon tissues were collected at 3 and 60 days post MSC administration to evaluate the short-term and long-term effects of MSCs on inflammation and enteric neuropathy by histological and immunohistochemical analyses. In a separate set of experiments, multiple treatments with 4 × 10⁶ and 2 × 10⁶ MSCs were performed and tissue collected at 3 days post treatment. Chronic intestinal inflammation in Winnie mice was associated with persistent diarrhea, perianal bleeding, morphological changes, and immune cell infiltration in the colon. Significant changes to the ENS, including impairment of cholinergic, noradrenergic and sensory innervation, and myenteric neuronal loss were prominent in Winnie mice. Treatment with a single dose of bone marrow-derived MSCs was ineffective in attenuating chronic inflammation and enteric neuropathy in Winnie.

Stem cell therapy for Crohn's disease: systematic review and meta-analysis of preclinical and clinical studies

Background

We explored whether stem cell therapy was effective for animal models and patients with Crohn’s disease (CD).

Methods

We searched five online databases. The relative outcomes were analyzed with the aid of GetData Graph Digitizer 2.26 and Stata 16.0 software. The SYRCLE risk of bias tool and the MINORS tool were used to assess study quality.

Results

We evaluated 46 studies including 28 animal works (n = 567) and 18 human trials (n = 360). In the animal studies, the disease activity index dramatically decreased in the mesenchymal stem cell (MSC) treatment groups compared to the control group. Rats and mice receiving MSCs exhibited longer colons [mice: standardized mean difference (SMD) 2.84, P = 0.000; rats: SMD 1.44, P = 0.029], lower histopathological scores (mice: SMD − 4.58, p = 0.000; rats: SMD − 1.41, P = 0.000) and lower myeloperoxidase levels (SMD − 6.22, P = 0.000). In clinical trials, stem cell transplantation reduced the CD activity index (SMD − 2.10, P = 0.000), the CD endoscopic index of severity (SMD − 3.40, P = 0.000) and simplified endoscopy score for CD (SMD − 1.71, P = 0.000) and improved the inflammatory bowel disease questionnaire score (SMD 1.33, P = 0.305) compared to control values. CD patients maintained high remission rates for 3–24 months after transplantation.

Conclusions

Stem cell transplantation is a valuable supplementary therapy for CD.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-021-02533-0.

Phosphatidylserine externalized on the colonic capillaries as a novel pharmacological target for IBD therapy

Inflammatory bowel disease (IBD) is a chronic and relapsing disorder for many people associated with poor health. Although there are some clinical drugs for IBD treatment, the development of effective therapeutics on IBD patients has always been necessary. Here, we show that externalized phosphatidylserine (PS) is observed on the surface of colonic capillaries. Annexin A5 (ANXA5) with high affinity for PS has a good targeting to the colon and effectively alleviates experimental colitis. In contrast, ANXA5 mutant (A5m) lacking the PS-binding ability, has no accumulation in the colon and no therapeutic effects on colitis. Mechanistic investigations indicate that ANXA5 reduces the inflammatory cell infiltration by inhibiting endothelial cell activation dependent on PS-binding ability. With the increasing of PS exposure on activated HUVECs (human umbilical vein endothelial cells), ANXA5 binding induces the internalization of TLR4 via PS-dependent endocytosis. We provide new insights on the molecular mechanism of ANXA5 for its anti-inflammatory effect. Our data suggest that PS-externalization is a potential target of ANXA5 aiming at targeted drug delivery (TDD) for IBD treatment.

Cancer-Preventive Role of Bone Marrow-Derived Mesenchymal Stem Cells on Colitis-Associated Colorectal Cancer: Roles of Gut Microbiota Involved

BACKGROUND

Mesenchymal stem cells (MSCs) treatment showed promising results in inflammatory bowel disease in both rodent models and patients. Nevertheless, previous studies conducted conflicting results on preclinical tumor models treated with MSCs concerning their influence on tumor initiation and progression. This study is designed to demonstrate the role of bone marrow-derived MSCs and the potential mechanism in the colitis-associated colon cancer (CAC) model.

METHODS

Bone marrow-derived MSCs were isolated from green fluorescent protein-transgenic mice, cultured, and identified by flow cytometry. Azoxymethane and dextran sulfate sodium were administrated to establish the CAC mouse model, and MSCs were infused intraperitoneally once per week. The mice were weighed weekly, and colon length, tumor number, and average tumor size were assessed after the mice were killed. MSC localization was detected by immunofluorescence staining; tumor cell proliferation and apoptosis were measured by immunohistochemistry staining of Ki-67 and terminal deoxynucleotidyl transferase deoxyuridine triphosphate nick end labeling assay, respectively. The colonic tumor tissues were isolated for RNA-seq, and fecal samples were collected for 16S ribosomal RNA sequencing of the microbiome.

RESULTS

After injection intraperitoneally, MSCs migrated to the intestine and inhibited the initiation of colitis-associated colorectal cancer. This inhibition effect was marked by less weight loss, longer colon length, and reduced tumor numbers. Moreover, MSCs reduced tumor cell proliferation and induced tumor cell apoptosis. Furthermore, MSCs could inhibit chronic inflammation assessed by RNA-sequencing and promote gut microbiome normalization detected by 16S ribosomal RNA sequencing.

CONCLUSION

The results proved that MSCs could migrate to the colon, inhibit chronic inflammation, and regulate gut microbiome dysbiosis to suppress the development of CAC.

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.

Mesenchymal Stromal Cell Therapy in the Management of Perianal Fistulas in Crohn's Disease: An Up-To-Date Review

Crohn’s Disease (CD) is a chronic inflammatory disorder that potentially involves the entire gastrointestinal tract. Perianal fistulizing CD (pCD) is a serious and frequent complication associated with significant morbidities and a heavy negative impact on quality of life. The aim of CD treatment is to induce and maintain disease remission and to promote mucosal repair. Unfortunately, even the best therapeutic regimens in pCD do not have long-term efficacy and cause a significant number of side effects. Therefore, it is mandatory to study new therapeutical options such as the use of mesenchymal stromal cells (MSCs). These cells promote tissue repair via the induction of immunomodulation. The present review aims to analyze the existing updated scientific literature on MSCs adoption in the treatment of pCD to evaluate its efficacy and safety and to compare the use of bone marrow and adipose tissue derived MSCs, type of administration, and dose required for recovery.

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.

IGF-1C hydrogel improves the therapeutic effects of MSCs on colitis in mice through PGE2-mediated M2 macrophage polarization

Background: Mesenchymal stem cell (MSC)-based therapies hold great promise for the treatment of inflammatory bowel disease (IBD). In order to optimize and maximize the therapeutic benefits of MSCs, we investigated whether cotransplantation of a chitosan (CS)-based injectable hydrogel with immobilized IGF-1 C domain peptide (CS-IGF-1C) and human placenta-derived MSCs (hP-MSCs) could ameliorate colitis in mice. Methods: IGF-1C hydrogel was generated by immobilizing IGF-1C to CS hydrogel. Colitis was induced by 2,4,6-trinitrobenzene sulfonic acid (TNBS) in mice. We initially applied hP-MSCs and CS-IGF-1C hydrogel for the treatment of colitis by in situ injection, and molecular imaging methods were used for real-time imaging of reactive oxygen species (ROS) and tracking of transplanted hP-MSCs by bioluminescence imaging (BLI). Furthermore, the effects of CS-IGF-1C hydrogel on prostaglandin E₂ (PGE₂) secretion of hP-MSCs and polarization of M2 macrophages were investigated as well. Results: The CS-IGF-1C hydrogel significantly increased hP-MSC proliferation and promoted the production of PGE₂ from hP-MSCs in vitro. Moreover, in vivo studies indicated that the CS-IGF-1C hydrogel promoted hP-MSC survival as visualized by BLI and markedly alleviated mouse colitis, which was possibly mediated by hP-MSC production of PGE₂ and interleukin-10 (IL-10) production by polarized M2 macrophages. Conclusions: The CS-IGF-1C hydrogel improved the engraftment of transplanted hP-MSCs, ameliorated inflammatory responses, and further promoted the functional and structural recovery of colitis through PGE₂-mediated M2 macrophage polarization. Molecular imaging approaches and therapeutic strategies for hydrogel application provide a versatile platform for exploring the promising therapeutic potential of MSCs in the treatment of IBD.

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.

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

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

Mesenchymal stem cell therapy for the treatment of inflammatory diseases: Challenges, opportunities, and future perspectives

Mesenchymal stem cells (MSCs) are promising alternative agents for the treatment of inflammatory disorders due to their immunomodulatory functions, and several clinical trials on MSC-based products are currently being conducted. In this review, we discuss recent progress made on the use of MSCs as immunomodulatory agents, developmental challenges posed by MSC-based therapy, and the strategies being used to overcome these challenges. In this context, current understanding of the mechanisms responsible for MSC interactions with the immune system and the molecular responses of MSCs to inflammatory signals are discussed. The immunosuppressive activities of MSCs are initiated by cell-to-cell contact and the release of immuno-regulatory molecules. By doing so, MSCs can inhibit the proliferation and function of T cells, natural killer cells, B cells, and dendritic cells, and can also increase the proliferation of regulatory T cells. However, various problems, such as low transplanted cell viability, poor homing and engraftment into injured tissues, MSC heterogeneity, and lack of adequate information on optimum MSC doses impede clinical applications. On the other hand, it has been shown that the immunomodulatory activities and viabilities of MSCs might be enhanced by 3D-cultured systems, genetic modifications, preconditioning, and targeted-delivery.

Therapeutic effects of a single injection of human umbilical mesenchymal stem cells on acute and chronic colitis in mice

Multiple injections of bone marrow mesenchymal stem cells (BMMSCs) have been used for treatment of chronic colitis in mice. We aimed to report the therapeutic effects of a single injection of human umbilical cord mesenchymal stem cells (hUCMSCs) on acute and chronic colitis. Male C57BL/6JNarl mice were divided into control, phosphate-buffered saline (PBS), and hUCMSCs treated groups, respectively. Acute and chronic colitis were induced in the mice (except controls) using 3% dextran sulfate sodium (DSS). The mice in the hUCMSCs group underwent a single injection of hUCMSCs. The disease activity index (DAI), colon length, histology, colon inflammation score, in vivo stem cells images, and blood cytokine levels were recorded. The DAI was significantly higher in the hUCMSCs group than in the control group and lower than in the PBS group on all days. The colon length was significantly longer and the colon inflammation score was significantly lower in the hUCMSCs group than in the PBS group on days 8 and 25. IL17A, Gro-α, MIP-1α, MIP-2, and eotaxin were significantly lower in the hUCMSCs group than in the PBS group on days 8 and 25. Single-injection hUCMSCs improved DSS–induced acute colitis and decreased progression of acute colitis to chronic colitis.

A single administration of human adipose tissue-derived mesenchymal stromal cells (MSC) induces durable and sustained long-term regulation of inflammatory response in experimental colitis

Current therapies for inflammatory bowel diseases (IBD) are aimed at controlling the exacerbated response in the gut, but no treatment is fully effective for many refractory patients. Mesenchymal stromal cells (MSC) are multi-potent cells with regulatory immunosuppressive activity that may control inflammatory diseases. In this study, we investigated the short- and especially the long-term protective effects of MSC on experimental colitis. We show that MSC elicited protection to acute intestinal inflammation with gain of weight, improvement in the clinical disease score and expressive reduction in the mortality rate of treated mice. MSC changed the population of neutrophils, eosinophils and augmented the frequency of CD4 T lymphocytes in the gut-draining lymph nodes, together with reduced accumulation of these cells in the colon intraepithelial compartment. Interestingly, there were increased levels of programmed death 1 (PD-1) and glucocorticoid-induced tumour necrosis factor receptor family-related receptor (GITR) in the spleen regulatory T cells of mice that received MSC treatment, which also presented a reversal in the pattern of immune response in the gut, with diminished inflammatory, T helper type 1 (Th1) and Th17 profile, in contrast to augmented Th2 responses. Most strikingly, this balanced response elicited by a single administration of MSC during the acute colitis persisted long-term, with restored goblet cells, eosinophils and maintenance of elevated gut interleukin (IL)-4, besides increased CD4⁺ CD25⁺ PD-1⁺ cells in the spleen and reduced Th17 response in mesenteric lymph nodes (MLN) of treated mice on day 60. Taken together, our findings provided a significant contribution to translational immunology by pointing human adipose tissue-derived MSC as a novel therapeutic approach with long-term beneficial regulatory effects in experimental colitis.

Standardization of mesenchymal stromal cell therapy for perianal fistulizing Crohn's disease

BACKGROUND

Local administration of mesenchymal stromal cells (MSCs) into the fistula tract seems to improve patient outcome in perianal fistulas due to Crohn's disease (CD). In this paper we propose a standardized and validated protocol for the local administration of MSCs for CD perianal fistulas to be able to reliably assess efficacy.

MATERIALS AND METHODS

A working group consisting of gastroenterologists and surgeons with expertise in the treatment of perianal CD developed a consensus perianal fistula treatment protocol for local MSC treatment of perianal fistulizing CD. The treatment protocol was validated during a trial of allogeneic bone marrow-derived MSCs for the treatment of refractory perianal Crohn's fistulas.

RESULTS

Localization and classification of perianal fistulas with MRI and rectoscopy is of crucial importance prior to surgical intervention with local therapy administration. Examination under anesthesia is necessary to incise and drain abscesses when present. Optimization of medical treatment when active luminal CD is present, is the first step before embarking on surgery and local therapy administration. In addition, strictures preventing the surgeon from adequately performing the surgical procedure have to be endoscopically dilated. Curettage of the fistula tract has an important role as long-standing CD perianal fistulas close poorly without removal of their epithelial lining. To diminish bacterial contamination of the fistula, the internal opening has to be closed. The origin of the fistula is the internal opening, therefore, efficacy of MSCs is presumably the highest when they are injected into the tissue around the internal opening.

CONCLUSION

In this article, we propose a standardized method of local MSC administration for perianal fistulizing CD. The use of this standardized and validated protocol for the administration of local treatment of CD perianal fistulas will allow reliable comparison of the efficacy of local therapies in future.

Mesenchymal stem cell transplantation improves chronic colitis-associated complications through inhibiting the activity of toll-like receptor-4 in mice

Background

A variety of extra-intestinal manifestations (EIMs), including hepatobiliary complications, are associated with inflammatory bowel disease (IBD). Mesenchymal stem cells (MSCs) have been shown to play a potential role in the therapy of IBD. This study was designed to investigate the effect and mechanism of MSCs on chronic colitis-associated hepatobiliary complications using mouse chronic colitis models induced by dextran sulfate sodium (DSS).

Methods

DSS-induced mouse chronic colitis models were established and treated with MSCs. Severity of colitis was evaluated by disease activity index (DAI), body weight (BW), colon length and histopathology. Serum lipopolysaccharide (LPS) levels were detected by limulus amebocyte lysate test (LAL-test). Histology and liver function of the mice were checked correspondingly. Serum LPS levels and bacterial translocation of mesenteric lymph nodes (MLN) were detected. Pro-inflammatory cytokines including tumor necrosis factor-α (TNF-α), interferon-γ (IFN-γ), interleukin-1β (IL-1β), interleukin-17A (IL-17A), Toll receptor 4 (TLR4), TNF receptor-associated factor 6 (TRAF6) and nuclear factor kappa B (NF-κB) were detected by immunohistochemical staining, western blot analysis and real-time PCR, respectively.

Results

The DSS-induced chronic colitis model was characterized by reduced BW, high DAI, worsened histologic inflammation, and high levels of LPS and E. coli. Liver histopathological lesions, impaired liver function, enhanced proteins and mRNA levels of TNF-α, IFN-γ, IL-1β, IL-17A, TLR4, TRAF6 and NF-κB were observed after DSS administration. MSCs transplantation markedly ameliorated the pathology of colon and liver by reduction of LPS levels and proteins and mRNA expressions of TNF-α, IFN-γ, IL-1β, IL-17A, TLR4, TRAF6 and NF-κB.

Conclusions

MSCs can improve chronic colitis-associated hepatobiliary complications, probably by inhibition of enterogenous endotoxemia and hepatic inflammation through LPS/TLR4 pathway. MSCs may represent a novel therapeutic approach for chronic colitis-associated hepatobiliary complications.

Comparative Analysis between the In Vivo Biodistribution and Therapeutic Efficacy of Adipose-Derived Mesenchymal Stromal Cells Administered Intraperitoneally in Experimental Colitis

Mesenchymal stem cells (MSCs) have emerged as a promising treatment for inflammatory diseases. The immunomodulatory effect of MSCs takes place both by direct cell-to-cell contact and by means of soluble factors that leads to an increased accumulation of regulatory immune cells at the sites of inflammation. Similar efficacy of MSCs has been described regardless of the route of administration used, the inflammation conditions and the major histocompatibility complex context. These observations raise the question of whether the migration of the MSCs to the inflamed tissues is a pre-requisite to achieve their beneficial effect. To address this, we examined the biodistribution and the efficacy of intraperitoneal luciferase-expressing human expanded adipose-derived stem cells (Luci-eASCs) in a mouse model of colitis. Luci-eASC-infused mice were stratified according to their response to the Luci-eASC treatment. According to the stratification criteria, there was a tendency to increase the bioluminescence signal in the intestine at the expense of a decrease in the bioluminescence signal in the liver in the “responder” mice. These data thus suggest that the accumulation of the eASCs to the inflamed tissues is beneficial for achieving an optimal modulation of inflammation.

Modern management of perianal fistulas in Crohn's disease: future directions

Perianal fistulae in patients with Crohn's disease (CD) can be associated with significant morbidity resulting in negative impact on quality of life. The last two decades have seen significant advancements in the management of perianal fistulas in CD, which has evolved into a multidisciplinary approach that includes gastroenterologists, colorectal surgeons, endoscopists and radiologists. Despite the introduction of new medical therapies such as antitumour necrosis factor and novel models of care delivery, the best fistula healing rates reported with combined medical and surgical approaches are approximately 50%. More recently, newer biologics, cell-based therapies as well as novel endoscopic and surgical techniques have been introduced raising new hopes that outcomes can be improved upon. In this review, we describe the modern management and the most recent advances in the management of complex perianal fistulising CD, which will likely impact clinical practice. We will explore optimal use of both older and newer biological agents, as well as new data on cell-based therapies. In addition, new techniques in endoscopic and surgical approaches will be discussed.

Mesenchymal Stem Cells (MSC) Derived from Induced Pluripotent Stem Cells (iPSC) Equivalent to Adipose-Derived MSC in Promoting Intestinal Healing and Microbiome Normalization in Mouse Inflammatory Bowel Disease Model

Cellular therapy with allogeneic or autologous mesenchymal stem cells (MSC) has emerged as a promising new therapeutic strategy for managing inflammatory bowel disease (IBD). However, MSC therapy ideally requires a convenient and relatively homogenous cell source (typically bone marrow or adipose tissues) and the ability to generate cells with stable phenotype and function. An alternative means of generating allogeneic MSC is to derive them from induced pluripotent stem cells (iPSC), which could in theory provide an indefinite supply of MSC with well-defined phenotype and function. Therefore, we compared the effectiveness of iPSC-derived MSC (iMSC) and adipose-derived MSC (adMSC) in a mouse model of IBD (dextran sodium sulfate-induced colitis), and investigated mechanisms of intestinal protection. We found that iMSC were equivalent to adMSC in terms of significantly improving clinical abnormalities in treated mice and reducing lesion scores and inflammation in the gut. Administration of iMSC also stimulated significant intestinal epithelial cell proliferation, increased in the numbers of Lgr5+ intestinal stem cells, and increased intestinal angiogenesis. In addition, the microbiome alterations present in mice with colitis were partially restored to resemble those of healthy mice following treatment with iMSC or adMSC. Thus, iMSC administration improved overall intestinal health and healing with equivalent potency to treatment with adMSC. This therefore is the first report of the effectiveness of iMSC in the treatment of IBD, along with a description of unique mechanisms of action with respect to intestinal healing and microbiome restoration. Stem Cells Translational Medicine 2018;7:456-467.

Immunotherapy in inflammatory bowel disease: Novel and emerging treatments

Inflammatory bowel disease (IBD) is a chronic disabling inflammatory process that affects young individuals, with growing incidence. The etiopathogenesis of IBD remains poorly understood. A combination of genetic and environmental factors triggers an inadequate immune response against the commensal intestinal flora in IBD patients. Thus, a better understanding of the immunological mechanisms involved in IBD pathogenesis is central to the development of new therapeutic options.

Current pharmacological treatments used in clinical practice like thiopurines or anti-TNF are effective but can produce significant side effects and their efficacy may diminish over time. In fact, up to one third of the patients do not have a satisfactory response to these therapies. Consequently, the search for new therapeutic strategies targeting alternative immunological pathways has intensified. Several new oral and parenteral substances are in the pipeline for IBD.

In this review we discuss novel therapies targeting alternative pro-inflammatory pathways like IL-12/23 axis, IL-6 pathway or Janus Kinase inhibitors; as well as others modulating anti-inflammatory signalling pathways like transforming growth factor-β1 (TGF-β1). We also highlight new emerging therapies targeting the adhesion and migration of leukocytes into the inflamed intestinal mucosa by blocking selectively different subunits of α₄β₇ integrins or binding alternative adhesion molecules like MAdCAM-1. Drugs reducing the circulating lymphocytes by sequestering them in secondary lymphoid organs (sphingosine-1-phosphate (S1P) receptor modulators) are also discussed. Finally, the latest advances in cell therapies using mesenchymal stem cells or engineered T regs are reviewed. In addition, we provide an update on the current status in clinical trials of these new immune-regulating therapies that open a new era in the treatment of IBD.

TSG-6 released from intraperitoneally injected canine adipose tissue-derived mesenchymal stem cells ameliorate inflammatory bowel disease by inducing M2 macrophage switch in mice

BACKGROUND

Inflammatory bowel disease (IBD) is an intractable autoimmune disorder that markedly deteriorates one's quality of life. Mesenchymal stem cells (MSCs) alleviate inflammation by modulating inflammatory cytokines in inflamed tissues, and have been suggested as a promising alternative for IBD treatment in human and veterinary cases. Furthermore, tumor necrosis factor-α-induced gene/protein 6 (TSG-6) is a key factor influencing MSC immunomodulatory properties; however, the precise mechanism of TSG-6 release from canine MSCs in IBD remains unclear. This study aimed to assess the therapeutic effects of canine adipose tissue-derived (cAT)-MSC-produced TSG-6 in an IBD mouse model and to explore the mechanisms underlying the immunomodulatory properties.

METHODS

Mice with dextran sulfate sodium-induced colitis were administered cAT-MSCs intraperitoneally; colon tissues were collected on day 10 for histopathological, quantitative real-time polymerase chain reaction, and immunofluorescence analyses.

RESULTS

cAT-MSC-secreted TSG-6 ameliorated IBD and regulated colonic expression of pro- and anti-inflammatory cytokines such as tumor necrosis factor-α, interleukin-6, and interleukin-10. To investigate the effect of cAT-MSC-secreted TSG-6 on activated macrophages in vitro, a transwell coculture system was used; TSG-6 released by cAT-MSCs induced a macrophage phenotypic switch from M1 to M2. The cAT-MSC-secreted TSG-6 increased M2 macrophages in the inflamed colon in vivo.

CONCLUSIONS

TSG-6 released from cAT-MSCs can alleviate dextran sulfate sodium-induced colitis by inducing a macrophage phenotypic switch to M2 in mice.

Can a Conversation Between Mesenchymal Stromal Cells and Macrophages Solve the Crisis in the Inflamed Intestine?

Inflammatory bowel disease (IBD) is a group of chronic inflammatory conditions of the gastrointestinal tract characterized by an exacerbated mucosal immune response. Macrophages play pivotal roles in the maintenance of gut homeostasis but they are also implicated in the pathogenesis of IBD. They are highly plastic cells and their activation state depends on the local environment. In the healthy intestine, resident macrophages display an M2 phenotype characterized by inflammatory energy, while inflammatory M1 macrophages dominate in the inflamed intestinal mucosa. In this regard, modifying the balance of macrophage populations into an M2 phenotype has emerged as a new therapeutic approach in IBD. Multipotent mesenchymal stromal cells (MSCs) have been proposed as a promising cell-therapy for the treatment of IBD, considering their immunomodulatory and tissue regenerative potential. Numerous preclinical studies have shown that MSCs can induce immunomodulatory macrophages and have demonstrated that their therapeutic efficacy in experimental colitis is mediated by macrophages with an M2-like phenotype. However, some issues have not been clarified yet, including the importance of MSC homing to the inflamed colon and/or lymphoid organs, their optimal route of administration or whether they are effective as living or dead cells. In contrast, the mechanisms behind the effect of MSCs in human IBD are not known and more data are needed regarding the effect of MSCs on macrophage polarization that would support the observation reported in the experimental models. Nevertheless, MSCs have emerged as a novel method to treat IBD that has already been proven safe and with clinical benefits that could be administered in combination with the currently used pharmacological treatments.

Advances in mesenchymal stromal cell therapy in the management of Crohn's disease

The aim of therapy in Crohn's disease (CD) is induction and maintenance of remission, promotion of mucosal healing and restoration of quality of life. Even the best treatment regimes, including combinations of biologics and immunomodulators lack durable efficacy and have well documented side effects. Accordingly, there is an unmet need for novel therapies. Mesenchymal stromal cells (MSCs) are a subset of non-hematopoietic stem cells that home to sites of inflammation where they exert potent immunomodulatory effects and contribute to tissue repair. Their utility is being explored in several inflammatory and immune mediated disorders including CD, where they have demonstrated favourable safety, feasibility and efficacy profiles. Areas covered: This review highlights current knowledge on MSC therapy and critically evaluates their safety, efficacy and potential mechanisms of action in CD. Expert commentary: Building on positive early phase clinical trials and a recent phase 3 trial in perianal CD, there is considerable optimism for the possibility of MSCs changing the treatment landscape in complicated CD. Although important questions remain unanswered, including the safety and durability of MSC therapy, optimal adjunctive therapies and their sourcing and manufacturing, it is anticipated that MSCs are likely to enter mainstream treatment algorithms in the near future.

Mesenchymal Stem Cell Injections for the Treatment of Perianal Crohn's Disease: What We Have Accomplished and What We Still Need to Do

Perianal Crohn's disease [CD] is found in a quarter of patients with CD and remains notoriously difficult to treat. Several medical and surgical therapies are available. However, none is particularly effective nor reliably provides sustained remission. In addition, surgical intervention is complicated by poor healing and the potential for incontinence. Mesenchymal stem cell-based therapies provide a promising treatment alternative for perianal CD, with demonstrated safety, improved efficacy, and a decreased side effect profile. Several phase I, II, and now III randomised controlled trials have now reported safety and efficacy in treating perianal CD. The aim of this review is to discusses the outcomes of conventional treatment approaches, outcomes of mesenchymal stem cell therapies, considerations specific to stem cell-based therapies, and future directions for research.

Human umbilical cord mesenchymal stem cells increase interleukin-9 production of CD4+ T cells

Mesenchymal stem cells (MSC) are able to differentiate into cells of multiple lineage, and additionally act to modulate the immune response. Interleukin (IL)-9 is primarily produced by cluster of differentiation (CD)4⁺ T cells to regulate the immune response. The present study aimed to investigate the effect of human umbilical cord derived-MSC (UC-MSC) on IL-9 production of human CD4⁺ T cells. It was demonstrated that the addition of UC-MSC to the culture of CD4⁺ T cells significantly enhanced IL-9 production by CD4⁺ T cells. Transwell experiments suggested that UC-MSC promotion of IL-9 production by CD4⁺ T cells was dependent on cell-cell contact. Upregulated expression of CD106 was observed in UC-MSC co-cultured with CD4⁺ T cells, and the addition of a blocking antibody of CD106 significantly impaired the ability of UC-MSC to promote IL-9 production by CD4⁺ T cells. Therefore, the results of the present study demonstrated that UC-MSC promoted the generation of IL-9 producing cells, which may be mediated, in part by CD106. The findings may act to expand understanding and knowledge of the immune modulatory role of UC-MSC.

Mesenchymal stem cells and their therapeutic applications in inflammatory bowel disease

Mesenchymal stem or stromal cells (MSCs) are non-hematopoietic stem cells that facilitate tissue regeneration through mechanisms involving self-renewal and differentiation, supporting angiogenesis and tissue cell survival, and limiting inflammation. MSCs were originally identified and expanded in long-term cultures of cells from bone marrow and other organs; and their native identity was recently confined into pericytes and adventitial cells in vascularized tissue. The multipotency, as well as the trophic and immunosuppressive effects, of MSCs have prompted the rapid development of clinical applications for many diseases involving tissue inflammation and immune disorders, including inflammatory bowel disease. Although standard criteria have been established to define MSCs, their therapeutic efficacy has varied significantly among studies due to their natural heterogenicity. Thus, understanding the biological and immunological features of MSCs is critical to standardize and optimize MSCs-based therapy. In this review, we highlight the cellular and molecular mechanisms involved in MSCs-mediated tissue repair and immunosuppression. We also provide an update on the current development of MSCs-based clinical trials, with a detailed discussion of MSC-based cell therapy in inflammatory bowel disease.

The neuroprotective effects of human bone marrow mesenchymal stem cells are dose-dependent in TNBS colitis

Background

The incidence of inflammatory bowel diseases (IBD) is increasing worldwide with patients experiencing severe impacts on their quality of life. It is well accepted that intestinal inflammation associates with extensive damage to the enteric nervous system (ENS), which intrinsically innervates the gastrointestinal tract and regulates all gut functions. Hence, treatments targeting the enteric neurons are plausible for alleviating IBD and associated complications. Mesenchymal stem cells (MSCs) are gaining wide recognition as a potential therapy for many diseases due to their immunomodulatory and neuroprotective qualities. However, there is a large discrepancy regarding appropriate cell doses used in both clinical trials and experimental models of disease. We have previously demonstrated that human bone marrow MSCs exhibit neuroprotective and anti-inflammatory effects in a guinea-pig model of 2,4,6-trinitrobenzene-sulfonate (TNBS)-induced colitis; but an investigation into whether this response is dose-dependent has not been conducted.

Methods

Hartley guinea-pigs were administered TNBS or sham treatment intra-rectally. Animals in the MSC treatment groups received either 1 × 10⁵, 1 × 10⁶ or 3 × 10⁶ MSCs by enema 3 hours after induction of colitis. Colon tissues were collected 72 hours after TNBS administration to assess the effects of MSC treatments on the level of inflammation and damage to the ENS by immunohistochemical and histological analyses.

Results

MSCs administered at a low dose, 1 × 10⁵ cells, had little or no effect on the level of immune cell infiltrate and damage to the colonic innervation was similar to the TNBS group. Treatment with 1 × 10⁶ MSCs decreased the quantity of immune infiltrate and damage to nerve processes in the colonic wall, prevented myenteric neuronal loss and changes in neuronal subpopulations. Treatment with 3 × 10⁶ MSCs had similar effects to 1 × 10⁶ MSC treatments.

Conclusions

The neuroprotective effect of MSCs in TNBS colitis is dose-dependent. Increasing doses higher than 1 × 10⁶ MSCs demonstrates no further therapeutic benefit than 1 × 10⁶ MSCs in preventing enteric neuropathy associated with intestinal inflammation. Furthermore, we have established an optimal dose of MSCs for future studies investigating intestinal inflammation, the enteric neurons and stem cell therapy in this model.

Review article: mesenchymal stromal cell therapy for inflammatory bowel diseases

BACKGROUND

Inflammatory bowel diseases (IBD) are chronic relapsing diseases in which pro-inflammatory immune cells and cytokines induce intestinal tissue damage and disability. Mesenchymal stromal cells (MSCs) exert powerful immunomodulatory effects and stimulate tissue repair.

AIM

To review the current data on mesenchymal stromal cell therapy in IBD.

METHOD

We searched PubMed and 'ClinicalTrials.gov' databases using the terms 'mesenchymal stromal cells', 'mesenchymal stem cell transplantation', 'inflammatory bowel diseases', 'Crohn disease' and 'colitis, ulcerative'. Additional publications were identified from individual article reference lists.

RESULTS

MSCs include inhibition of Th1/Th17 lymphocytes and recruitment of regulatory T lymphocytes, induction of antigen-presenting cells into a regulatory-like profile, and stimulation of epithelial cell differentiation and proliferation. More than 200 patients with refractory fistulas have been treated with local injections of MSCs, resulting in complete response in more than half, and in overall response in approximately two thirds of patients. In refractory luminal Crohn's disease, 49 cases of systemic MSC infusions have been reported, while trials with autologous MSCs resulted in mitigated responses, studies using allogeneic MSCs were promising, with around 60% of patients experiencing a response and around 40% achieving clinical remission.

CONCLUSIONS

Mesenchymal stromal cells might represent a promising therapy for IBD, especially for Crohn's disease. There remain many unsolved questions concerning the optimal origin and source of mesenchymal stromal cells, dosage and modalities of administration. Moreover, mesenchymal stromal cells still need to prove their effectiveness compared with conventional treatments in randomised controlled trials.

Induction of Indoleamine 2,3-dioxygenase by Pre-treatment with Poly(I:C) May Enhance the Efficacy of MSC Treatment in DSS-induced Colitis

Mesenchymal stem cells (MSCs) have been used experimentally for treating inflammatory disorders, partly owing to their immunosuppressive properties. The goal of the study was to determine whether TLR ligands can enhance the therapeutic efficacy of bone marrow-derived MSCs for the treatment of inflammatory bowel disease. Mice (C57BL6) were administered with 4% dextran sulfate sodium (DSS) in drinking water for 7 days and injected with MSCs on days 1 and 3 following DSS ingestion. Our results demonstrated that among various TLR ligands, MSCs treated with polyinosinic-polycytidylic acid [poly(I:C)], which is a TLR3 ligand, more profoundly induced IDO, which is a therapeutically relevant immunosuppressive factor, without any observable phenotype change in vitro. The poly(I:C)-treated MSCs attenuated the pathologic severity of DSS-induced murine colitis when injected i.p. but not i.v. In summary, preconditioning MSCs with poly(I:C) might improve their efficacy in treating DSS-induced colitis, and this effect at least partly depends on the enhancement of their immunosuppressive activity through increasing their production of IDO.

Human umbilical cord-derived mesenchymal stem cells protect against experimental colitis via CD5(+) B regulatory cells

Background

To clarify the effect of human umbilical cord-derived mesenchymal stem cell (hUC-MSCs) treatment on colitis and to explore the role of CD5⁺ B cells in MSC therapy.

Methods

The trinitrobenzenesulfonic acid (TNBS)-induced colitis mouse model was used. HUC-MSCs were transferred peritoneally. Survival rates, colitis symptoms, and macroscopic and histologic scores were evaluated. CD4⁺ T helper (Th) cell subgroups and CD5⁺ regulatory B cell (Bregs) in lymphocytes were quantitated by flow cytometry. Cytokine levels were detected by ELISA and Bio-plex. CD5⁺ B cells were isolated for in vitro co-culture and adaptive transfer.

Results

HUC-MSC treatment alleviated TNBS-induced colitis by increasing survival rates, relieving symptoms, and improving macroscopic and histologic scores. Labeled hUC-MSCs were located in the inflamed areas of colitis mice. Increases in regulatory T cells (Tregs) and CD5⁺ B cells and decreases in Th1 cells, Th17 cells, and several pro-inflammatory cytokines were observed with hUC-MSC treatment. After adaptive transfer, CD5⁺ B cells, which were located mainly in the peritoneal lavage fluid, improved TNBS-induced colitis by correcting Treg/Th1/Th17 imbalances. CD5⁺ B cells also inhibited T-cell proliferation and produced interleukin (IL)-10.

Conclusions

HUC-MSCs protected against experimental colitis by boosting the numbers of CD5⁺ B cells and IL-10-producing CD5⁺ Bregs, and correcting Treg/Th17/Th1 imbalances.

Electronic supplementary material

The online version of this article (doi:10.1186/s13287-016-0376-2) contains supplementary material, which is available to authorized users.

Transplantation of Human Placenta-Derived Mesenchymal Stem Cells Alleviates Critical Limb Ischemia in Diabetic Nude Rats

Neovasculogenesis induced by stem cell therapy is an innovative approach to improve critical limb ischemia (CLI) in diabetes. Mesenchymal stem cells (MSCs) are ideal candidates due to their angiogenic and immunomodulatory features. The aim of this study is to determine the therapeutic effects of human placenta-derived MSCs (P-MSCs) on diabetic CLI, with or without exogenous insulin administration, and the underlying mechanism of any effect. A series of in vitro experiments were performed to assess the stemness and vasculogenic activity of P-MSCs. P-MSCs were intramuscularly injected at two different doses with and without the administration of insulin. The efficacy of P-MSC transplantation was evaluated by ischemia damage score, ambulatory score, laser Doppler perfusion image (LDPI), capillary, and vascular density. In vivo imaging was applied to track the implanted P-MSCs. In vivo differentiation and in situ secretion of angiogenic cytokines were determined. In vitro experimental outcomes showed the differentiation potential and potent paracrine effect of P-MSCs. P-MSCs survived in vivo for at least 3 weeks and led to the acceleration of ischemia recovery, due to newly formed capillaries, increased arterioles, and secretion of various proangiogenic factors. P-MSCs participate in angiogenesis and vascularization directly through differentiation and cytokine expression.

Intraluminal Injection of Mesenchymal Stromal Cells in Spheroids Attenuates Experimental Colitis

BACKGROUND AND AIMS

In recent years, mesenchymal stromal cells [MSCs] emerged as a promising therapeutic option for various diseases, due to their immunomodulatory properties. We previously observed that intraperitoneally injected MSCs in experimental colitis form spherical shaped aggregates. Therefore, we aggregated MSCs in vitro into spheroids and injected them intraluminally in mice with established colitis, to investigate whether these MSC spheroids could alleviate the colitis.

METHODS

We injected 0.5 x 10(6) MSCs in spheroids, 2.0 x 10(6) MSCs in spheroids, or phosphate-buffered saline [PBS] as a treatment control, via an enema in mice with established dextran sulphate sodium [DSS]-induced colitis. Body weight was measured daily and disease activity score was determined at sacrifice. Endoscopy was performed to evaluate mucosal healing. After sacrifice, both systemic and local inflammatory responses were evaluated.

RESULTS

Intraluminally injected MSC spheroids alleviated DSS-induced colitis, resulting in significantly less body weight loss and lower disease activity score at sacrifice when a high dose of MSC spheroids was administered. However, the percentage of mucosal lesions in the distal colon and endoscopy scores were not significantly lower after treatment with 2.0 x 10(6) MSCs in spheroids compared with PBS-treated mice. Systemic inflammation marker serum amyloid A [SAA] was significantly reduced after treatment with 2.0 x 10(6) MSCs in spheroids. In addition, local cytokine levels of IFN-ɣ, TNF-α, IL-6, and IL-17a, as well as numbers of macrophages and neutrophils, showed a clear decrease-though not always significant-after intraluminal injection of the MSC spheroids.

CONCLUSION

Intraluminally injected MSC spheroids at least partially attenuate experimental colitis, with fewer phagocytes and proinflammmatory cytokines, when a high dose of MSCs in spheroids was administered.

Exosome Derived From Human Umbilical Cord Mesenchymal Stem Cell Mediates MiR-181c Attenuating Burn-induced Excessive Inflammation

Mesenchymal stem cell (MSC)-derived exosomes have diverse functions in regulating wound healing and inflammation; however, the molecular mechanism of human umbilical cord MSC (hUCMSC)-derived exosomes in regulating burn-induced inflammation is not well understood. We found that burn injury significantly increased the inflammatory reaction of rats or macrophages exposed to lipopolysaccharide (LPS), increased tumor necrosis factor α (TNF-α) and interleukin-1β (IL-1β) levels and decreased IL-10 levels. hUCMSC-exosome administration successfully reversed this reaction. Further studies showed that miR-181c in the exosomes played a pivotal role in regulating inflammation. Compared to control hUCMSC-exosomes, hUCMSC-exosomes overexpressing miR-181c more effectively suppressed the TLR4 signaling pathway and alleviated inflammation in burned rats. Administration of miR-181c-expressing hUCMSC-exosomes or TLR4 knockdown significantly reduced LPS-induced TLR4 expression by macrophages and the inflammatory reaction. In summary, miR-181c expression in hUCMSC-exosomes reduces burn-induced inflammation by downregulating the TLR4 signaling pathway.

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hUCMSC-exosome administration attenuated burn-induced inflammation

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miR-181c in hUCMSC-exosome served an pivotal role in regulating inflammation

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miR-181c repressed burn-induced inflammation via targeting TLR4

This study wants to address the potential function of exosomal miRNA on regulating burn-induced inflammation, and our results indicated that exosome derived from stem cells administration attenuated burn-induced inflammation of rats. Further study elucidated that miR-181c might serve an essential role in regulating inflammation. miR-181c suppressed toll-like receptor 4 expression, and subsequently reduced the expression of pro-inflammatory factors TNF-α, IL-1β. Forced expression of miR-181c in exosome further alleviated burn-induced inflammation. So our study provided a complete understanding of exosomal miR-181c in regulating burn-induced inflammation and its potentials as clinical therapeutic target of burn patients.

Human cord blood-derived platelet lysate enhances the therapeutic activity of adipose-derived mesenchymal stromal cells isolated from Crohn's disease patients in a mouse model of colitis

Introduction

Due to their immunomodulatory properties, mesenchymal stromal cells (MSCs) have been used for auto-immune disease treatment. Crohn disease (CD) and ulcerative colitis are two major inflammatory bowel diseases (IBDs), resulting from pathological immune responses to environmental or microbial antigens. Preclinical and clinical studies have suggested that MSC-based cellular therapy hold promising potential for IBD treatment. However, open issues include the selection of the proper cell dose, the source and the optimal route of administration of MSCs for more effective results. Platelet lysate has gained clinical interest due to its efficacy in accelerating wound healing. Thus, we propose to combine the administration of MSCs with a human umbilical cord blood-derived platelet lysate (hCBPL) as a novel strategy to improve MSC-based therapy for IBD resolution.

Methods

Colitis was induced in 8-week-old C57BL/6J mice by daily oral administration of dextran sulphate sodium (DSS) (1.5 % w/v in tap water) for 9 days. MSCs were isolated from adipose tissue of CD patients (adCD-MSCs), expanded in proliferation medium, resuspended in hCBPL or PBS and administrated via enema for three times (1 × 10⁶ cells/mouse/time) every other day starting on day +7 from DSS induction. The colitis evolution was evaluated by daily monitoring of body weight, stool consistency and bleeding. Histopathological analysis was performed. Inflammatory cytokine plasma levels were determined. adCD-MSCs stained with lipophilic membrane dye Nile Red, were injected in DSS mice as described above. Colon section of mice sacrificed 24 hours after last cell administration, were analyzed by confocal microscopy.

Results

We found that adCD-MSCs could be easily isolated and expanded from CD patients. Upon injection, adCD-MSCs exerted a therapeutic effect on DSS-induced colitis. Moreover, hCBPL increased adCD-MSCs efficacy by significantly reducing colitis scores, extension of the colon inflamed area and plasma levels of inflammatory mediators. Finally, Nile Red staining of MSCs is very efficient, stable and does not impair their vitality and function. Nile Red-labelling was clearly detected in the colitic area of adCD-MSCs injected mice and it was significantly brighter in the colon sections of mice that had received adCD-MSCs/hCBPL.

Conclusions

In summary, with this study we propose a novel and promising adCD-MSC/hCBPL-based therapy for refractory IBDs.

Electronic supplementary material

The online version of this article (doi:10.1186/s13287-015-0166-2) contains supplementary material, which is available to authorized users.

Transplantation of human umbilical mesenchymal stem cells attenuates dextran sulfate sodium-induced colitis in mice

Ulcerative colitis is a major form of inflammatory bowel disease and increases the risk of the development of colorectal carcinoma. The anti-inflammatory and immunomodulatory properties of mesenchymal stem cells (MSC) make them promising tools for treating immune-mediated and inflammatory diseases. However, the lack of robust technique for harvesting and expanding of MSC has hampered the use of bone marrow and umbilical cord blood derived MSC in clinical applications. In the present study, we investigated the intestinal protective effects of Wharton's jelly-derived umbilical MSC (UMSC) on dextran sulfate sodium-induced colitis in mice. The severity of colitis in mice was assessed using bodyweight loss, stool consistency, rectal bleeding, colon shortening and haematological parameters. Colonic myeloperoxidase and pro-inflammatory cytokines levels were also measured. Furthermore, the expression of cyclooxygenase 2 and inducible nitric oxide synthase in the colon were detected. In addition, intestinal permeability and tight junction proteins expressions in the colon were examined as well. The results showed that Wharton's jelly-derived UMSC significantly diminished the severity of colitis, reduced histolopathological score, and decreased myeloperoxidase activity and cytokines levels. Furthermore, the UMSC markedly decreased the expression of cyclooxygenase 2and inducible nitric oxide synthase in the colon. In addition, transplantation of UMSC reduced intestinal permeability and upregulated the expression of tight junction proteins. These results show that the anti-inflammation and regulation of tight junction proteins by Wharton's jelly-derived UMSC ameliorates colitis.

Mesenchymal stromal cells and chronic inflammatory bowel disease

Recent experimental findings have shown the ability of mesenchymal stromal cells (MSCs) to home to damaged tissues and to produce paracrine factors with anti-inflammatory properties, potentially resulting in reduction of inflammation and functional recovery of the damaged tissues. Prompted by these intriguing properties and on the basis of encouraging preclinical data, MSCs are currently being studied in several immune-mediated disorders. Inflammatory bowel diseases (IBD) represent a setting in which MSCs-based therapy has been extensively investigated. Phase I and II studies have documented the safety and feasibility of MSCs. However, efficacy results have so far been conflicting. In this review, we will discuss the biologic rationale that makes MSCs a promising therapeutic tool for IBD, and analyze recent experimental and clinical findings, highlighting current limitations and future perspectives of MSCs-related immunotherapy for IBD.