Subcutaneous adipose tissue-derived stem cells facilitate colonic mucosal recovery from 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced colitis in rats

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.

Conditioned medium from stem cells derived from human exfoliated deciduous teeth ameliorates NASH via the Gut-Liver axis

Non-alcoholic steatohepatitis (NASH) occurrence has been increasing and is becoming a major cause of liver cirrhosis and liver cancer. However, effective treatments for NASH are still lacking. We examined the benefits of serum-free conditioned medium from stem cells derived from human exfoliated deciduous teeth (SHED-CM) on a murine non-alcoholic steatohepatitis (NASH) model induced by a combination of Western diet (WD) and repeated administration of low doses of carbon tetrachloride intraperitoneally, focusing on the gut-liver axis. We showed that repeated intravenous administration of SHED-CM significantly ameliorated histological liver fibrosis and inflammation in a murine NASH model. SHED-CM inhibited parenchymal cell apoptosis and reduced the activation of inflammatory macrophages. Gene expression of pro-inflammatory and pro-fibrotic mediators (such as Tnf-α, Tgf-β, and Ccl-2) in the liver was reduced in mice treated with SHED-CM. Furthermore, SHED-CM protected intestinal tight junctions and maintained intestinal barrier function, while suppressing gene expression of the receptor for endotoxin, Toll-like receptor 4, in the liver. SHED-CM promoted the recovery of Caco-2 monolayer dysfunction induced by IFN-γ and TNF-α in vitro. Our findings suggest that SHED-CM may inhibit NASH fibrosis via the gut-liver axis, in addition to its protective effect on hepatocytes and the induction of macrophages with unique anti-inflammatory phenotypes.

Cell therapy in experimental model of inflammatory bowel disease

Inflammatory bowel disease, which mainly involves Crohn's disease and ulcerative rectocolitis, is an inflammatory condition of the mucosa that can afflict any segment of the gastrointestinal tract. Despite the fact that the existing therapies result in improvement in patient's symptomatology and quality of life, there is no curative treatment. Surgical treatment involves complex procedures associated with high morbidity and mortality rates. In this context, cell therapy with stem cells has emerged as a treatment with broad potential applicability. In this study, we intended to verify the efficacy of transplantation of adipose tissue-derived stem cells in rats with intestinal inflammation induced by trinitrobenzenesulfonic acid. The cell population was isolated from the adipose tissue of inguinal region of rats and processed for culture by mechanical dissociation. The animals were evaluated with respect to clinical and biochemical aspects, as well as by macroscopic, microscopic and histological analyses. In the experimental model of bowel inflammation by 2,4,6-trinitrobenzenesulfonic acid, the infusion of adipose tissue significantly reduced the presence of adhesions in the colon and adjacent organs and decreased the activity of myeloperoxidase, a marker of neutrophil infiltration in the injured mucosa. The results suggest that cell therapy with adipose tissue can promote and/or accelerate the regeneration of damaged intestinal mucosa. It is concluded that the presence of adhesions and the determination of myeloperoxidase activity provide indications that adipose tissue can promote and/or accelerate the regeneration of inflammatory bowel mucosa.

Dental pulp stem cells overexpressing hepatocyte growth factor facilitate the repair of DSS-induced ulcerative colitis

Background

Ulcerative colitis (UC) is a chronic and recurrent disease without satisfactory treatment strategies. Dental pulp stem cell (DPSC) transplantation has been proposed as a potential therapy for UC. This study aimed to investigate the therapeutic effects of the rat hepatocyte growth factor (HGF) gene transduced into DPSCs for UC.

Methods

The therapeutic effects of HGF-DPSCs transplanted intravenously into a rat model of UC induced by 5% dextran sulphate sodium (DSS) were compared with the other treatment groups (LV-HGF group, DPSCs group and GFP-DPSCs group). Immunofluorescence and immunohistochemistry were used to observe the localization and proliferation of HGF-DPSCs at the site of colon injury. The expression levels of inflammatory factors were detected by real-time quantitative PCR (RT-PCR) and western blotting. The oxidative stress markers were detected by ELISA. DAI scores and body weight changes were used to macroscopically evaluate the treatment of rats in each group.

Results

Immunofluorescence and immunohistochemistry assays showed that HGF-DPSCs homed to colon injury sites and colocalized with intestinal stem cell (ISC) markers (Bmi1, Musashi1 and Sox9) and significantly promoted protein expression (Bmi1, Musashi1, Sox9 and PCNA). Anti-inflammatory cytokine (TGF-β and IL-10) expression was the highest in the HGF-DPSCs group compared with the other treatment groups, while the expression of pro-inflammatory cytokines (TNF-α and INF-γ) was the lowest. Additionally, the oxidative stress response results showed that malondialdehyde (MDA) and myeloperoxidase (MPO) expression decreased while superoxide dismutase (SOD) expression increased, especially in the HGF-DPSCs group. The DAI scores showed a downward trend with time in the five treatment groups, whereas body weight increased, and the changes were most prominent in the HGF-DPSCs group.

Conclusions

The study indicated that HGF-DPSCs can alleviate injuries to the intestinal mucosa by transdifferentiating into ISC-like cells, promoting ISC-like cell proliferation, suppressing inflammatory responses and reducing oxidative stress damage, which provides new ideas for the clinical treatment of UC.

Effects of experimental colitis in rats on incretin levels, inflammatory markers, and enteric neuronal function

INTRODUCTION

The aim of the study was to assess the effects of chronic inflammation on incretin levels, inflammatory markers, and enteric neuronal function measured in isolated preparations of smooth muscle of rat.

MATERIAL AND METHODS

We induced experimental colitis using 2,4-dinitrobenzenesulfonic acid (DNBS) in 17 Albino male Sprague-Dawley rats, while 16 rats were used as a control. They were housed in temperature-controlled rooms in a 12-h light/dark cycle at 22-24°C and 50 to 60% humidity. We evaluated in both inflamed and healthy rats: fasting plasma glucose concentration, fasting plasma insulin, myeloperoxidase, active glucose-dependent insulinotropic peptide (GIP), glucagon-like peptide-1 (GLP-1), and GLP-2 levels, adiponectin, and C-reactive protein (CRP). We also evaluated colonic longitudinal smooth muscle contractile activity.

RESULTS

Intrarectal administration of DNBS reduced body weight gain in inflamed rats. We recorded higher levels of fasting plasma glucose, and insulin in inflamed rats. We observed higher levels of myeloperoxidase and CRP, and lower levels of ADN in inflamed rats. We recorded higher levels of GIP, GLP-1, and GLP-2 in inflamed rats compared to the healthy ones. Regarding functional response of colon intestinal smooth muscle after electrical stimulation, we recorded a lower functional response of colon intestinal smooth muscle after electrical stimulation in inflamed rats.

CONCLUSIONS

We can conclude that chronic inflammation leads to an increase of incretin levels and to a decrease of functional response of colon intestinal smooth muscle after electrical stimulation.

The recruitment of extra-intestinal cells to the injured mucosa promotes healing in radiation enteritis and chemical colitis in a mouse parabiosis model

Mucosal healing occurs through migration and proliferation of cells within injured epithelium, yet these processes may be inadequate for mucosal healing after significant injury where the mucosa is denuded. We hypothesize that extra-intestinal cells can contribute to mucosal healing after injury to the small and large intestine. We generated parabiotic pairs between wild-type and tdTomato mice, which were then subjected to radiation-induced enteritis and 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced colitis. We now show that as compared with singleton mice, mice with a parabiotic partner were protected against intestinal damage as revealed by significantly reduced weight loss, reduced expression of pro-inflammatory cytokines, reduced enterocyte apoptosis, and improved crypt proliferation. Donor cells expressed CD45-, Sca-1+, c-kit+, and CXCR4+ and accumulated around the injured crypts but did not transdifferentiate into epithelia, suggesting that extra-intestinal cells play a paracrine role in the healing response, while parabiotic pairings with Rag1-/- mice showed improved healing, indicating that adaptive immune cells were dispensable for mucosal healing. Strikingly, ablation of the bone marrow of the donor parabionts removed the protective effects. These findings reveal that the recruitment of extra-intestinal, bone marrow-derived cells into the injured intestinal mucosa can promote mucosal healing, suggesting novel therapeutic approaches for severe intestinal disease.

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.

Endoscopic submucosal injection of adipose-derived mesenchymal stem cells ameliorates TNBS-induced colitis in rats and prevents stenosis

Background

Mesenchymal stem cells have potential applications in inflammatory bowel disease due to their immunomodulatory properties. Our aim was to evaluate the feasibility, safety and efficacy of endoscopic administration of adipose-derived mesenchymal stem cells (ASCs) in a colitis model in rats.

Methods

Colitis was induced in rats by rectal trinitrobenzenesulfonic acid (TNBS). After 24 h ASCs (10⁷ cells) or saline vehicle were endoscopically injected into the distal colon. Rats were followed for 11 days. Daily weight, endoscopic score at days 1 and 11, macroscopic appearance at necropsy, colon length and mRNA expression of Foxp3 and IL-10 in mesenteric lymph nodes (MLN) were analyzed.

Results

Endoscopic injection was successful in all the animals. No significant adverse events or mortality due to the procedure occurred. Weight evolution was significantly better in the ASC group, recovering initial weight by day 11 (− 0.8% ± 10.1%, mean ± SD), whereas the vehicle group remained in weight loss (− 6.7% ± 9.2%, p = 0.024). The endoscopic score improved in the ASC group by 47.1% ± 5.3% vs. 21.8% ± 6.6% in the vehicle group (p < 0.01). Stenosis was less frequent in the ASC group (4.8% vs. 41.2%, p < 0.01). Colon length significantly recovered in the ASC group versus the vehicle group (222.6 ± 17.3 mm vs. 193.6 ± 17.9 mm, p < 0.001). The endoscopic score significantly correlated with weight change, macroscopic necropsy score and colon length. Foxp3 and IL-10 mRNA levels in MLN recovered with ASC treatment.

Conclusions

ASC submucosal endoscopic injection is feasible, safe and ameliorates TNBS-induced colitis in rats, especially stenosis.

Electronic supplementary material

The online version of this article (10.1186/s13287-018-0837-x) contains supplementary material, which is available to authorized users.

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.

Biodistribution and Efficacy of Human Adipose-Derived Mesenchymal Stem Cells Following Intranodal Administration in Experimental Colitis

Mesenchymal stem cells (MSCs) have a large potential in cell therapy for treatment of inflammatory and autoimmune diseases, thanks to their immunomodulatory properties. The encouraging results in animal models have initiated the translation of MSC therapy to clinical trials. In cell therapy protocols with MSCs, administered intravenously, several studies have shown that a small proportion of infused MSCs can traffic to the draining lymph nodes (LNs). This is accompanied with an increase of different types of regulatory immune cells in the LNs, suggesting the importance of migration of MSCs to the LNs in order to contribute to immunomodulatory response. Intranodal (IN), also referred as intralymphatic, injection of cells, like dendritic cells, is being proposed in the clinic for the treatment of cancer and allergy, showing that this route of administration is clinically safe and efficient. In this study, we investigated, for the first time, the biodistribution and the efficacy of Luciferase⁺ adipose-derived MSCs (Luci-eASCs), infused through the inguinal LNs (iLNs), in normal mice and in inflamed mice with colitis. Most of the Luci-eASCs remain in the iLNs and in the adipose tissue surrounding the inguinal LNs. A small proportion of Luci-eASCs can migrate to other locations within the lymphatic system and to other tissues and organs, having a preferential migration toward the intestine in colitic mice. Our results show that the infused Luci-eASCs protected 58% of the mice against induced colitis. Importantly, a correlation between the response to eASC treatment and a higher accumulation of eASCs in popliteal, parathymic, parathyroid, and mesenteric LNs were found. Altogether, these results suggest that IN administration of eASCs is feasible and may represent an effective strategy for cell therapy protocols with human adipose-derived MSCs in the clinic for the treatment of immune-mediated disorders.

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.

Circulating Bone Marrow-Derived CD45-/CD34+/CD133+/VEGF+ Endothelial Progenitor Cells in Adults with Crohn's Disease

BACKGROUND

Circulating endothelial progenitor cells (EPCs) are bone marrow-derived stem cells able to migrate to sites of damaged endothelium and differentiate into endothelial cells. Altered EPC level and function have been described in various inflammatory diseases and have been shown to augment vasculogenesis in murine models. Previous studies of EPC in the context of Crohn's disease (CD) have yielded conflicting results.

AIM

To determine whether the circulating levels of EPCs are changed in the context of CD.

METHODS

CD patients and healthy controls were recruited. Disease activity was assessed by CDAI. Peripheral blood mononuclear cells were isolated and EPC numbers evaluated by FACS analysis using anti-CD34, anti-VEGF receptor-2, anti-CD133, and anti-CD45 markers.

RESULTS

Eighty-three subjects, including 32 CD patients and 51 controls were recruited, including 19 (59.4 %) and 23 (45 %) males (p = 0.26), aged 34.8 ± 14.9 and 43.3 ± 18.5 years (p = 0.64), in cases and controls, respectively. Mean CDAI was 147 ± 97, disease duration was 12.7 ± 11.1 years, and 28 (87.5 %) were receiving biologics for a mean duration of 21.7 ± 16.8 months. The mean level of peripheral EPCs in CD patients was 0.050 ± 0.086 percent and 0.007 ± 0.013 % in controls (p < 0.01). There was no significant correlation between EPC levels and age (r = -0.13, p = 0.47), CDAI (r = -0.26, p = 0.15), disease duration (r = -0.04, p = 0.84), or duration of treatment with biologics (r = 0.004, p = 0.99).

CONCLUSION

EPCs are elevated in patients with CD. Further studies are needed to examine the function of EPCs and their possible role as a marker of disease severity or therapeutic response.

The role of adipose stem cells in inflammatory bowel disease: From biology to novel therapeutic strategies

Inflammatory bowel diseases are an increasing phenomenon in western countries and in growing populations. The physiopathology of these conditions is linked to intestinal stem cells homeostasis and regenerative potential in a chronic inflammatory microenvironment. Patients with IBD present an increased risk of developing colorectal cancer (CRC), or colitis associated cancer (CAC). Conventional treatment for IBD target the inflammatory process (and include anti-inflammatory and immunosuppressive drugs) with biological agents emerging as a therapeutic approach for non-responders to traditional therapy. Conventional treatment provides scarce results and present severe complications. The intestinal environment may host incoming stem cells, able to engraft in the epithelial damaged sites and differentiate. Therefore, stem cell therapies represent an emerging alternative in inflammatory bowel diseases, with current investigations on the use of haematopoietic and mesenchymal stem cells, in particular adipose stem cells, apparently fundamental as regenerators and as immune-modulators. Here, we discuss stem cells in intestinal homeostasis and as therapeutic agents for the treatment of inflammatory bowel diseases.

Intravenous administration of mesenchymal stem cells overexpressing CXCR4 protects against experimental colitis in rats

AIM: To investigate the role of SDF-1α/CXCR4 axis in the therapeutic effects of lentivirus-preconditioned bone mesenchymal stem cells (BMSCs) for 2,4,6-trinitrobenzene sulfonic acid (TNBS)- induced colitis in rats.

METHODS: BMSCs were isolated from Sprague-Dawley (SD) rats and identified by flow cytometry. Lentivirus transfection was applied to over-express CXCR4/GFP (Ad-CXCR4-BMSCs) or null/GFP (Ad-GFP-BMSCs) in BMSCs. Thirty-two SD rats were randomly divided into four groups (n = 8): a control group, a model group, an Ad-GFP-BMSCs group and an Ad-CXCR4-BMSCs group. The rats were grouped to receive various treatments by tail vein injections. On day 1, colitis was induced by the TNBS administration. On day 12, animals were anesthetized and submitted to a laparotomy under sterile conditions. The distal colon was then opened longitudinally, slightly cleaned in physiological saline for faecal residue removal, and tissue samples were harvested and analyzed for various studies.

RESULTS: One week after intravenous administration, Ad-GFP-BMSCs failed to colonize in the inflamed colon and had no beneficial effect in TNBS-induced colitis. Instead, Ad-CXCR4-BMSCs signally ameliorated both clinical and microanatomical severity of colitis. Immunofluorescence and Western blot showed that Ad-CXCR4-BMSCs migrated toward inflamed colon was more efficient than Ad-GFP-BMSCs. The therapeutic effect of Ad-CXCR4-BMSCs was mediated by the suppression of pro-inflammatory cytokines and STAT3 phosphorylation in injured colon.

CONCLUSION: Our data indicate that over-expression of CXCR4 promotes the in vivo mobilization and engraftment of BMSCs into inflamed colon where these cells can function as an anti-inflammatory and immunomodulatory component of the immune system in TNBS-induced colitis.

Human adult stem cells derived from adipose tissue and bone marrow attenuate enteric neuropathy in the guinea-pig model of acute colitis

Introduction

Mesenchymal stem cells (MSCs) have been identified as a viable treatment for inflammatory bowel disease (IBD). MSCs derived from bone marrow (BM-MSCs) have predominated in experimental models whereas the majority of clinical trials have used MSCs derived from adipose tissue (AT-MSCs), thus there is little consensus on the optimal tissue source. The therapeutic efficacies of these MSCs are yet to be compared in context of the underlying dysfunction of the enteric nervous system innervating the gastrointestinal tract concomitant with IBD. This study aims to characterise the in vitro properties of MSCs and compare their in vivo therapeutic potential for the treatment of enteric neuropathy associated with intestinal inflammation.

Methods

BM-MSCs and AT-MSCs were validated and characterised in vitro. In in vivo experiments, guinea-pigs received either 2,4,6-trinitrobenzene-sulfonate acid (TNBS) for the induction of colitis or sham treatment by enema. MSCs were administered at a dose of 1x10⁶ cells via enema 3 hours after the induction of colitis. Colon tissues were collected 24 and 72 hours after TNBS administration to assess the level of inflammation and damage to the ENS. MSC migration to the myenteric plexus in vivo was elucidated by immunohistochemistry and in vitro using a modified Boyden chamber assay.

Results

Cells exhibited multipotency and a typical surface immunophenotype for validation as bona fide MSCs. In vitro characterisation revealed distinct differences in growth kinetics, clonogenicity and cell morphology between MSC types. In vivo, BM-MSCs were comparatively more effective than AT-MSCs in attenuating leukocyte infiltration and neuronal loss in the myenteric plexus. MSCs from both sources equally ameliorated body weight loss, gross morphological damage to the colon, changes in the neurochemical coding of neuronal subpopulations and the reduction in density of extrinsic and intrinsic nerve fibres innervating the colon. MSCs from both sources migrated to the myenteric plexus in in vivo colitis and in an in vitro assay.

Conclusions

These data from in vitro experiments suggest that AT-MSCs are ideal for cellular expansion. However, BM-MSCs were more therapeutic in the treatment of enteric neuropathy and plexitis. These characteristics should be considered when deciding on the MSC tissue source.

Therapeutic effects of mouse bone marrow-derived clonal mesenchymal stem cells in a mouse model of inflammatory bowel disease

Mouse bone marrow-derived clonal mesenchymal stem cells (mcMSCs), which were originated from a single cell by a subfractionation culturing method, are recognized as new paradigm for stem cell therapy featured with its homogenous cell population. Next to proven therapeutic effects against pancreatitis, in the current study we demonstrated that mcMSCs showed significant therapeutic effects in dextran sulfate sodium (DSS)-induced experimental colitis model supported with anti-inflammatory and restorative activities. mcMSCs significantly reduced the disease activity index (DAI) score, including weight loss, stool consistency, and intestinal bleeding and significantly increased survival rates. The pathological scores were also significantly improved with mcMSC. We have demonstrated that especial mucosal regeneration activity accompanied with significantly lowered level of apoptosis as beneficiary actions of mcMSCs in UC models. The levels of inflammatory cytokines including TNF-α, IFN-γ, IL-1β, IL-6, and IL-17 were all significantly concurrent with significantly repressed NF-κB activation compared to the control group and significantly decreased infiltrations of responsible macrophage and neutrophil. Conclusively, our findings provide the rationale that mcMSCs are applicable as a potential source of cell-based therapy in inflammatory bowel diseases, especially contributing either to prevent relapse or to accelerate healing as solution to unmet medical needs in IBD therapy.

Mesenchymal stromal cell therapy for Crohn's disease

Current treatment approaches fail to address the underlying factors responsible for the pathogenesis of Crohn's disease (CD). Mesenchymal stromal cells (MSCs) are fibroblastic plastic adherent cells with specific surface markers, and may demonstrate trilineage differentiation ability. MSCs can be isolated from either the adipose tissue, bone marrow or umbilical cord. In refractory fistulizing CD, both autologous and allogeneic MSC therapy with repeated administrations is a feasible and safe therapeutic option with suggestion of efficacy, and several phase 3 trials are currently underway to determine its efficacy. In this review, we discuss the potential therapeutic role of MSC therapy for CD, which is predominantly related to its immunomodulatory role. The characteristics of MSCs derived from patients with CD and its pharmacological interaction are outlined. Preclinical studies using experimental models of colitis and clinical studies using MSCs for the treatment of fistulizing CD are highlighted. Finally, the current perspective and potential limitations of this novel therapy with recommendations for future studies are discussed.

Conditioned mesenchymal stem cells produce pleiotropic gut trophic factors

BACKGROUND

Although mounting evidence implicates mesenchymal stem cells (MSCs) in intestinal tissue repair, controversy remains regarding the engraftment, proliferation, and differentiation for repopulating MSCs in recipient tissues. Therefore, we investigated the paracrine and/or endocrine role of MSCs in experimental colitis.

METHODS

We analyzed the therapeutic effects of MSC-conditioned medium (MSC-CM) on dextran sulfate sodium (DSS)- or 2,4,6-trinitrobenzenesulfonic acid (TNBS)-induced colitis. We investigated the effects of MSC-CM on the epithelial cell viability, mobility, cell cycle, and cytokine production in ex vivo lamina propria/mesenteric lymphocytes, a macrophage cell line, and the mixed lymphocyte reaction. An optimal regimen against colitis was explored. The contents of MSC-CM were analyzed using a WNT signaling pathway polymerase chain reaction array, an inflammatory cytokines antibody array, and liquid chromatography-tandem mass spectrometry analysis.

RESULTS

Independent of the systemic administration route, MSC-CM concentrates were effective for the inductive phase of TNBS-induced colitis and for the recovery phase of DSS-induced colitis. Hypoxia appeared to be one of the optimal preconditioning factors assessed by cell motility and viability through activating the PI3K-Akt pathway in rat small intestine epithelial cells, IEC-6. Thus, Hypoxia had profound effects on the contents of MSC-CM, which comprised pleiotropic gut trophic factors involved in each wound healing process, including the anti-inflammatory, proliferative, and tissue remodeling phases.

CONCLUSIONS

Identification and optimization of potential gut trophic factors in MSC-CM is urgently needed to form the basis for new drug discovery and for optimizing cell-based therapies for inflammatory bowel disease.

SDF-1α/CXCR4 axis facilitates BMSCs homing toward injured colon in rats with experimental colitis

AIM: To investigate whether the stromal cell-derived factor-1α (SDF-1α)/chemokine receptor 4 (CXCR4) axis mediates the therapeutic effects of bone marrow-derived mesenchymal stem cells (BMSCs) for 2, 4, 6-trinitrobenzene sulfonic acid (TNBS)-colitis in rats.

METHODS: BMSCs were isolated from Sprague-Dawley (SD) rats and identified by flow cytometry. Lentivirus transfection was applied to over-express CXCR4/GFP (Ad-CXCR4-BMSCs) or null/GFP (Ad-GFP-BMSCs), and Western blot was applied to detect the protein expression of CXCR4 in BMSCs. Thirty-two SD rats were randomly divided into four groups (n = 8 for each group): a control group, a model group, an Ad-GFP-BMSCs group and an Ad-CXCR4-BMSCs group. Experimental colitis was induced with TNBS, and Ad-CXCR4-BMSCs or Ad-GFP-BMSCs were administered intravenously. One week after cell therapy, the colons were harvested. The expressions of GFP and SDF-1α in colon tissues were measured by Western blot and immunofluorescence.

RESULTS: The cell viability was approximately 90%, and 80% of BMSCs steadily carried the GFP protein after lentivirus transfection. Compared with the control group, the protein expression of SDF-1α was distinctly increased in injured colon in the model group. One week after cell therapy, Ad-GFP-BMSCs failed to colonize in the inflamed colon and had no beneficial effect on pathological inflammation score compared to the vehicle group (3.50 ± 0.53 vs 3.62 ± 0.52, P > 0.05). Compared with the model group, Ad-CXCR4-BMSCs signally down-regulated the disease activity index (2.71 ± 0.28 vs 3.88 ± 0.17, P < 0.01) and pathological inflammation score (2.25 ± 0.71 vs 3.62 ± 0.52, P < 0.01). Compared to the Ad-GFP-BMSCs group, the protein expression of GFP was significantly increased in the Ad-CXCR4-BMSCs group (0.70 ± 0.34 vs 0.10 ± 0.12, P < 0.01).

CONCLUSION: Our findings suggest that the SDF-1α/CXCR4 axis plays a crucial role in BMSCs migration toward injured colon, which may provide an attractive target for BMSCs-based therapies for IBD.

Over-expression of CXCR4 on mesenchymal stem cells protect against experimental colitis via immunomodulatory functions in impaired tissue

Bone marrow-derived mesenchymal stem cells (BMSCs) are attractive candidates for tissue regeneration and immunoregulation in inflammatory bowel disease. However, their in vivo reparative capability is limited owing to barren efficiency of BMSCs to injury region. Stromal cell-derived factor (SDF-1) plays an important role in chemotaxis and stem cell homing through interaction with its specific receptor CXC chemokine receptor 4 (CXCR4). The present study was designed to investigate the role of SDF-1α/CXCR4 axis in the therapeutic effects of lentivirus-preconditioned BMSCs for 2,4,6-trinitrobenzene sulfonic acid (TNBS)-colitis rats. BMSCs were isolated from female Sprague-Dawley rats and identified by flow cytometry. Lentiviral transduction was applied to over-express CXCR4/GFP (Ad-CXCR4-BMSCs) or null/GFP (Ad-GFP-BMSCs). Efficacy of engraftment was determined by the presence of enhanced green fluorescent protein (GFP) positive cells. One week after intravenous administration, Ad-GFP-BMSCs failed to colonize in the inflamed colon and had no beneficial effect in TNBS-induced colitis. Instead, Ad-CXCR4-BMSCs signally ameliorated both clinical and microanatomical severity of colitis. Immunofluorescence and western blotting showed that Ad-CXCR4-BMSCs migrated toward inflamed colon was more efficient than Ad-GFP-BMSCs. The therapeutic effect of Ad-CXCR4-BMSCs was mediated by the suppression of pro-inflammatory cytokines and STAT3 phosphorylation in injured colon. Collectively, our data indicated that over-expression CXCR4 led to enhance in vivo mobilization and engraftment of BMSCs into inflamed colon where these cells can function as an anti-inflammatory and immunomodulatory component of the immune system in TNBS-induced colitis.

Multi-therapeutic effects of human adipose-derived mesenchymal stem cells on radiation-induced intestinal injury

Radiation-induced intestinal injuries (RIII) commonly occur in patients who suffer from pelvic or abdominal cancer. However, current management of these injuries is ineffective. Recently, mesenchymal stem cells (MSCs) have been extensively used in regenerative medicine and have achieved a high level of efficacy. In the present study, we hypothesised that human adipose-derived mesenchymal stem cells (hAd-MSCs) could be used as potential tools to heal RIII. We observed that adult Sprague-Dawley rats that received whole-abdominal irradiation benefitted from hAd-MSC injection. hAd-MSCs had RIII-healing effects, including anti-inflammation, neovascularisation and maintenance of epithelium homeostasis, as indicated by elevated serum IL-10, upregulation of vascular endothelial growth factor, basic fibroblast growth factor and epidermal growth factor in irradiated intestine, mobilisation of CD31-positive haematopoietic stem cells or haematopoietic progenitor cells, and the prolonged presence of Bmi1-positive cells within crypts. Consequently, after hAd-MSC treatment, irradiated rats survived longer than non-treated animals. These results suggest that hAd-MSCs have therapeutic potential for RIII management.

Bone-marrow-derived mesenchymal stem cells for organ repair

Mesenchymal stem cells (MSCs) are prototypical adult stem cells with the capacity for self-renewal and differentiation with a broad tissue distribution. MSCs not only differentiate into types of cells of mesodermal lineage but also into endodermal and ectodermal lineages such as bone, fat, cartilage and cardiomyocytes, endothelial cells, lung epithelial cells, hepatocytes, neurons, and pancreatic islets. MSCs have been identified as an adherent, fibroblast-like population and can be isolated from different adult tissues, including bone marrow (BM), umbilical cord, skeletal muscle, and adipose tissue. MSCs secrete factors, including IL-6, M-CSF, IL-10, HGF, and PGE2, that promote tissue repair, stimulate proliferation and differentiation of endogenous tissue progenitors, and decrease inflammatory and immune reactions. In this paper, we focus on the role of BM-derived MSCs in organ repair.

Adipose-derived stem cells on the healing of ischemic colitis: a therapeutic effect by angiogenesis

BACKGROUND

There has been no specific treatment for ischemic colitis. We verified the effects of adipose-derived stem cells (ASCs) on ischemia-induced colitis in a rat model.

METHODS

Forty male Sprague-Dawley rats (10 weeks old; weight, 350 ± 20 g) were divided into two groups: a control group (only fibrinogen and thrombin injected, n = 20) and an ASC group (local implantation of ASCs mixed with thrombin and fibrinogen, n = 20). An ischemic colitis model was established by modifying Nagahata's methods with double-blind randomization. ASCs (1 × 10(6) cells) were implanted intramurally into the ischemic area using a fibrin glue mixture. The severity of adhesion, degree of ileus, the number and size of the ulcers, Wallace macroscopic and microscopic scores, and microvascular density were measured.

RESULTS

The degree of ileus was significantly lower, and significantly fewer and smaller ulcerations were found in the ASC group than those in the control group. Wallace macroscopic and microscopic scores were lower in the ASC group than in the control group (1.90 ± 1.22 versus 3.25 ± 1.83, p < 0.01 and 1.55 ± 1.88 versus 2.84 ± 1.89, p < 0.05, respectively). Microvascular density was higher in the ASC group than in the control (54.45 ± 19.45 versus 26.54 ± 13.14, p < 0.01, respectively).

CONCLUSIONS

Local implantation of ASCs into an ischemic-injured colonic wall reduced the grade of ischemic injury and enhanced tissue healing by promoting angiogenesis.

Various types of stem cells, including a population of very small embryonic-like stem cells, are mobilized into peripheral blood in patients with Crohn's disease

BACKGROUND

Developmentally early cells, including hematopoietic stem progenitor cells (HSPCs), mesenchymal stem cells (MSCs), endothelial progenitor cells (EPCs), and very small embryonic-like stem cells (VSELs), are mobilized into peripheral blood (PB) in response to tissue/organ injury. We sought to determine whether these cells are mobilized into PB in patients with Crohn's disease (CD).

METHODS

Twenty-five patients with active CD, 20 patients in clinical remission, and 25 age-matched controls were recruited and PB samples harvested. The circulating CD133+/Lin-/CD45+ and CD34+/Lin-/CD45+ cells enriched for HSPCs, CD105+/STRO-1+/CD45- cells enriched for MSCs, CD34+/KDR+/CD31+/CD45-cells enriched for EPCs, and small CXCR4+CD34+CD133+ subsets of Lin-CD45- cells that correspond to the population of VSELs were counted by fluorescence-activated cell sorting (FACS) and evaluated by direct immunofluorescence staining for pluripotency embryonic markers and by reverse-transcription polymerase chain reaction (RT-PCR) for expression of messenger (m)RNAs for a panel of genes expressed in intestine epithelial stem cells. The serum concentration of factors involved in stem cell trafficking, such as stromal derived factor-1 (SDF-1), vascular endothelial growth factor (VEGF), and hepatocyte growth factor (HGF) were measured by enzyme-linked immunosorbent assay (ELISA).

RESULTS

Our data indicate that cells expressing markers for MSCs, EPCs, and small Oct-4+Nanog+SSEA-4+CXCR4+lin-CD45- VSELs are mobilized into PB in CD. The mobilized cells also expressed at the mRNA level genes playing a role in development and regeneration of gastrointestinal epithelium. All these changes were accompanied by increased serum concentrations of VEGF and HGF.

CONCLUSIONS

CD triggers the mobilization of MSCs, EPCs, and VSELs, while the significance and precise role of these mobilized cells in repair of damaged intestine requires further study.

Localized colonic stem cell transplantation enhances tissue regeneration in murine colitis

Many patients suffer from chronic gastrointestinal diseases characterized by chronic inflammation, increased intestinal permeability and visceral pain in which there is no definitive treatment. Adult stem cells have recently been used in various disease states to contribute wound-healing processes. In the current study we investigated the ability of intra-colonic adult stem cells application to heal colonic inflammation in IL-10(-/-) mice with active colitis. The aims of this study were to determine whether intra-colonic infusion of adult colonic stem cells (CSCs) (local stem cell transplantation): (i) restores intestinal permeability; (ii) attenuates visceral hypersensitivity; (iii) heals murine colitis. IL-10(-/-) mice with active colitis were transplanted with adult stem cells. Mice received either a single intracolonic infusion of CSCs or colonic epithelial cells. Two weeks after transplantation, we measured visceral hypersensitivity and intestinal permeability and correlated these with histological improvement of colitis. IL-10(-/-) mice that received stem cell transplantation showed histopathologic evidence of recovery from colitis. Improvement in colitis as graded by pathology scores correlated with restoration of intestinal permeability and decreased visceral hypersensitivity. Intra-colonic administration of CSCs is a potential therapeutic method for treating refractory symptoms in patients with chronic gastrointestinal diseases associated with chronic inflammation and visceral hypersensitivity. This method may be safer and should have far fewer side effects than systemic stem cell administration.

Intraperitoneal but not intravenous cryopreserved mesenchymal stromal cells home to the inflamed colon and ameliorate experimental colitis

Background and Aims

Mesenchymal stromal cells (MSCs) were shown to have immunomodulatory activity and have been applied for treating immune-mediated disorders. We compared the homing and therapeutic action of cryopreserved subcutaneous adipose tissue (AT-MSCs) and bone marrow-derived mesenchymal stromal cells (BM-MSCs) in rats with trinitrobenzene sulfonic acid (TNBS)–induced colitis.

Methods

After colonoscopic detection of inflammation AT-MSCs or BM-MSCs were injected intraperitoneally. Colonoscopic and histologic scores were obtained. Density of collagen fibres and apoptotic rates were evaluated. Cytokine levels were measured in supernatants of colon explants. For cell migration studies MSCs and skin fibroblasts were labelled with Tc-99m or CM-DiI and injected intraperitonealy or intravenously.

Results

Intraperitoneal injection of AT-MSCs or BM-MSCs reduced the endoscopic and histopathologic severity of colitis, the collagen deposition, and the epithelial apoptosis. Levels of TNF-α and interleukin-1β decreased, while VEGF and TGF-β did not change following cell-therapy. Scintigraphy showed that MSCs migrated towards the inflamed colon and the uptake increased from 0.5 to 24 h. Tc-99m-MSCs injected intravenously distributed into various organs, but not the colon. Cm-DiI-positive MSCs were detected throughout the colon wall 72 h after inoculation, predominantly in the submucosa and muscular layer of inflamed areas.

Conclusions

Intraperitoneally injected cryopreserved MSCs home to and engraft into the inflamed colon and ameliorate TNBS-colitis.

Role of growth factors in the development of lymphangiogenesis driven by inflammatory bowel disease: a review

Studies on angiogenesis and lymphangiogenesis have gained special relevance in research into factors potentially influencing the pathogenesis and course of inflammatory bowel disease (IBD). The results of the few existing studies on the distribution and density of lymphatic vessels and blood vessels in the context of IBD are controversial. Studies using the specific lymphatic marker podoplanin have revealed a significantly large number of lymphatic vessels in the colonic mucosa of patients with ulcerative colitis and Crohn's disease (compared to patients with normal mucosa), whereas other authors have found no significant differences. However, the role of vascular endothelial growth factor (VEGF) tyrosine-kinase receptor 3 (VEGFR-3) in the onset of IBD has not been analyzed. In recent years new biochemical, molecular, and immunohistochemical studies indicate that several families of growth factors, such as the VEGF family and their receptors, fibroblast growth factor-2, platelet-derived growth factor-BB, hepatocyte growth factor, the angiopoietin system, and integrins may play an important role in the onset of IBD. To date, no comparative studies have analyzed these growth factors and specific lymphatic markers. We examine how growth factors are involved in the development of pathological lymphangiogenesis in patients with IBD and determine whether they play a crucial role in disease exacerbation.

Three-dimensional spheroid culture of human gingiva-derived mesenchymal stem cells enhances mitigation of chemotherapy-induced oral mucositis

Mesenchymal stem cells (MSCs) are capable of regenerative and immunomodulatory functions in cell-based therapies in a variety of human diseases and injuries; however, their therapeutic efficacy and potential side effects remain major obstacles in clinical applications. We report here a 3D spheroid culture approach to optimize stem cell properties and therapeutic effects of human gingiva-derived mesenchymal stem cells (GMSCs) in mitigation of experimental oral mucositis. Under growth condition of ultra-low attachment, GMSCs spontaneously aggregated into 3D spheroids and exhibited distinct early stem cell phenotype characterized by elevated expression Stro-1 and CXC chemokine receptor 4 (CXCR-4) as well as OCT-4 and Nanog, 2 important transcriptional factors relevant to stem cell properties, and decreased expression of MSC-associated markers, including CD29, CD90, and CD105. Functionally, spheroid GMSCs are capable of enhanced multipotency and augmented secretion of several chemokines and cytokines relevant to cell migration, survival, and angiogenesis. More importantly, spheroid GMSCs expressed increased levels of reactive oxygen species, hypoxia-inducible factor (HIF)-1 and -2α, and manganese superoxide dismutase, which correlated with improved resistance to oxidative stress-induced apoptosis. Using an in vivo murine model of chemotherapy-induced oral mucositis, we demonstrated that spheroid-derived GMSCs possessed better therapeutic efficacy than their adherent cells in reversing body weight loss and promoting the regeneration of disrupted epithelial lining of the mucositic tongues. These findings suggest that 3D spheroid culture allows early stemness preservation and potentially precondition GMSCs for enhanced mitigation of oral mucositis.

The implication of adiponectin and resistin in gastrointestinal diseases

Adiponectin and resistin, members of the adipokine family, are multi-task hormones involved in several disorders, including those of the alimentary tract. In the present review, eligible studies focusing on the role of adiponectin and resistin in gastrointestinal diseases are manifested together and classified according to anatomic criteria. In addition, similarities and common patterns have been recognized, ultimately revealing an inverse association: the down-regulation of adiponectin and up-regulation of resistin - both in vitro and in vivo - in gastrointestinal disorders, irrespective of their diverse nature - inflammatory, autoimmune or malignant - or anatomic position - esophageal, gastric, of the small intestine, colonic. Finally, a potential role for both adipokines in alimentary tract-related carcinogenesis has been identified, possibly representing a missing link between obesity and cancer.

Myogenic lineage differentiated mesenchymal stem cells enhance recovery from dextran sulfate sodium-induced colitis in the rat

BACKGROUND

Although mounting evidence implicates mesenchymal stem cells (MSCs) in intestinal tissue repair, uncertainty remains concerning the distribution, function, and fate of repopulating MSCs in recipient colonic tissues. Therefore, we investigated the role of transplanted MSCs in the repair phase of DSS colitis.

METHODS

LacZ-labeled rat MSCs were transplanted into rats with colitis induced by 4% DSS on day 2. Regular water replaced the DSS solution on day 6. Therapeutic effect was evaluated on day 9 by clinicopathologic and growth factor/cytokine expression profiles. We analyzed the Notch signaling pathway by Western blotting and characterized immunofluorescence of lacZ-labeled MSCs with confocal laser microscopy. In vivo differentiation of MSC was confirmed by transmission electron microscopy (TEM).

RESULTS

Recovery of colitis was modestly but significantly promoted by MSC transplantation due to proceeding cell cycle and inhibiting apoptosis in the epithelia. Tgfa mRNA expression increased significantly, while Notch signaling was inhibited in the colonic tissues with MSC transplantation. β-Galactosidase-positive cells, which expressed α-SMA, desmin, and vimentin, were infrequently detected in the lamina propria stroma. DSS exposure in vitro proved to be the most potent inducer for α-SMA in MSCs where TEM demonstrated myogenic lineage differentiation.

CONCLUSIONS

We found that MSCs transplantation modestly promoted the repair of DSS colitis. The donor-derived MSCs were likely reprogrammed to differentiate to myogenic lineage cells by cues from the micro milieu. Further characterization of these cells is warranted as a basis for applying cell-based therapy for inflammatory bowel disease.

The pivotal role of VEGF in adipose-derived-stem-cell-mediated regeneration

IMPORTANCE OF THE FIELD

Several lines of evidence suggest that VEGF is a key regulator of the paracrine effects of adipose-derived stem cells (ASCs), but the mechanism of action remains to be identified.

AREAS COVERED IN THIS REVIEW

This brief review discusses the following research questions: i) Does VEGF increase the proliferation/migration and differentiation of ASCs?; ii) Does VEGF mediate the paracrine effects of ASCs?; and iii) How is VEGF synthesized, and which factors regulate VEGF secretion?

WHAT THE READER WILL GAIN

External stimuli such as hypoxia may activate receptor tyrosine kinases in the membrane of ASCs, which, in turn, phosphorylate extracellular signal regulated kinase (ERK) and members of the Akt signaling pathway, stabilizing hypoxia inducible factor 1α (HIF-1α) that are primary regulators of VEGF expression. Secreted VEGF directly stimulates ASCs via VEGF receptors in an autocrine manner and regenerates damaged neighboring cells in a paracrine manner.

TAKE HOME MESSAGE

Most studies of stem cell regeneration have focused on differentiation of ASCs and their building block function; however, the paracrine effects of ASCs should also be the focus of attention.

Globular adiponectin as a complete mesoangioblast regulator: role in proliferation, survival, motility, and skeletal muscle differentiation

This article shows that globular adiponectin regulates vital cues of mesoangioblast, such as proliferation, survival, and migration toward myotubes and the myogenic properties. In vivo experiments confirm that globular adiponectin increases the survival, engraftment, and localization to muscle of mesoangioblasts in α-sarcoglycan-null mice.

Mesoangioblasts are progenitor endowed with multipotent mesoderm differentiation ability. Despite the promising results obtained with mesoangioblast transplantation in muscle dystrophy, an improvement of their efficient engrafting and survival within damaged muscles, as well as their ex vivo activation/expansion and commitment toward myogenic lineage, is highly needed and should greatly increase their therapeutic potential. We show that globular adiponectin, an adipokine endowed with metabolic and differentiating functions for muscles, regulates vital cues of mesoangioblast cell biology. The adipokine drives mesoangioblasts to entry cell cycle and strongly counteracts the apoptotic process triggered by growth factor withdrawal, thereby serving as an activating and prosurvival stem cell factor. In addition, adiponectin provides a specific protection against anoikis, the apoptotic death due to lack of anchorage to extracellular matrix, suggesting a key protective role for these nonresident stem cells after systemic injection. Finally, adiponectin behaves as a chemoattractive factor toward mature myotubes and stimulates their differentiation toward the skeletal muscle lineage, serving as a positive regulator in mesoangioblast homing to injured or diseased muscles. We conclude that adiponectin exerts several advantageous effects on mesoangioblasts, potentially valuable to improve their efficacy in cell based therapies of diseased muscles.

Requirement of IFN-gamma-mediated indoleamine 2,3-dioxygenase expression in the modulation of lymphocyte proliferation by human adipose-derived stem cells

Human adipose-derived mesenchymal stem cells (hASCs) are mesenchymal stem cells (MSCs) with reduced immunogenicity and capability to modulate immune responses. Whereas the immunosuppressive activity of bone marrow-MSCs has received considerable attention during the last few years, the specific mechanisms underlying hASC-mediated immunosuppression have been poorly studied. Recent studies comparing both cell types have reported differences at transcriptional and proteomic levels, suggesting that hASCs and bone marrow-MSCs, while having similarities, are quite different. This suggests that different mechanisms of immunosuppression may apply. Here, we report that hASCs inhibit peripheral blood mononuclear cells (PBMCs), and CD4(+) and CD8(+) T cell proliferation in both cell-cell contact and transwell conditions, which is accompanied by a reduction of proinflammatory cytokines. We demonstrate that hASCs do not constitutively express immunomodulatory factors. Conditioned supernatants from hASCs stimulated by IFN-gamma, PBMCs, or activated PBMCs highly inhibited PBMC proliferation, indicating that inhibitory factors are released upon hASC activation. Many factors have been involved in MSC-mediated immunosuppression, including IFN-gamma, IL-10, hepatocyte growth factor, prostaglandin E2, transforming growth factor-beta1, indoleamine 2,3-dioxygenase (IDO), nitric oxide, and IL-10. Using pharmacological inhibitors, neutralizing antibodies, and genetically modified hASCs that constitutively express or silence IDO enzyme, we demonstrate that, in the case of hASCs, the IFN-gamma/IDO axis is essential. Taken together, our data support the key role of IDO in the therapeutic use of hASC on immunomediated diseases.