Mesenchymal stem cells alleviate TNBS-induced colitis by modulating inflammatory and autoimmune responses

Mesenchymal stem cells and CXC chemokine receptor 4 overexpression improved the therapeutic effect on colitis via mucosa repair

The present study intended to observe the homing capability and therapeutic effect of CXC chemokine receptor 4 (CXCR-4) gene overexpressed bone marrow mesenchymal stem cells (BMSCs) on colitis, and to study the possible mechanisms involved. BMSCs were derived from male BALB/c mice and CXCR-4 gene was transfected into BMSCs by the utilization of the lentiviral vector. The expression of CXCR-4 gene was analyzed and the biological characteristics, and vitality of BMSCs and CXCR-4 gene overexpressed BMSCs (CXCR-BMSCs) were detected. The chemotaxis assay was performed to investigate migration in vitro. Colitis was induced by TNBS in female BALB/c mice. BMSCs and CXCR-BMSCs were injected into experimental models intravenously. The homing of cells was confirmed by fluorescence observation and Sry gene detection. Clinical manifestation and histological changes were also evaluated. The expression levels of occludin and vascular endothelial growth factor (VEGF) were detected to measure mucosal repair. Furthermore, CXCR-4 gene was successfully transfected into BMSCs by the utilization of lentiviral vector. Results indicated that overexpression of CXCR-4 gene did not influence the biological characteristics and vitality of BMSCs, but enhanced the capability of migration and homing of BMSCs in vitro and in vivo. Notably, CXCR-BMSCs had an improved effect on treating colitis, and the expression levels of Occludin and VEGF were higher. The results suggested that overexpression of CXCR-4 gene may enhance BMSC homing to damaged intestinal mucosa and their curative effect on colitis. The present findings indicated that using lentiviral vector to transfect CXCR-4 gene into BMSCs may be a potential method to improve the outcomes of BMSCs treatment on inflammatory bowel disease.

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.

Mesenchymal Stem Cells to Treat Crohn's Disease with Fistula

Crohn's disease, which mainly affects the gastrointestinal tract, is a refractory inflammatory disease that has clinical manifestations of abdominal pain, fever, bowel obstruction, and diarrhea with blood or mucus. Together, these symptoms can severely impair a patient's quality of life. Besides the common complication of intestinal obstruction, fistulas, particularly anorectal fistulas, are common in Crohn's disease patients. Since radical surgical cures can be difficult to achieve and relapse is common, Crohn's disease patients often seek other effective treatments in addition to surgery. Stem-cell therapies have recently been proposed as a method to address the challenges and prospective medical needs of Crohn's disease patients in general and those with fistulas. Several studies suggest that mesenchymal stem cells (MSCs) could improve Crohn's disease and Crohn's fistula. Moreover, studies concerning MSC transplantation or local rejection of stem cells derived from bone marrow or adipose tissue-derived stem cells have assessed stem cell-based treatments for refractory Crohn's disease. Many patients in these studies are now in remission. A number of clinical trials for refractory Crohn's disease have also evaluated transplantation of autologous or allogenic MSCs and showed that MSCs can be safely administered to Crohn's disease patients, with some achieving positive clinical responses.

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.

Interleukin-25 enhances the capacity of mesenchymal stem cells to induce intestinal epithelial cell regeneration

BACKGROUND

This study aimed to investigate the influence of IL-25 on the capacity of mesenchymal stem cells (MSCs) to induce intestinal epithelial cell regeneration.

METHODS

The CD4⁺IL-25R⁺ cells and LGR5⁺IL-25R⁺ cells in colonic mucosa of Crohn's disease (CD) patients, ulcerative colitis (UC) patients and healthy controls were detected by immunofluorescence staining, and the CD4⁺IL-25R⁺ cells in peripheral blood were detected by flow cytometry. Rat MSCs were separated and stimulated with IL-25. Then, MSCs were further incubated in IL-25-free DMEM for 24 h, and this DMEM was collected as conditioned medium (CM). IEC-6 cells were divided into 3 groups: experimental group (CM and TNF-α), control group (DMEM and TNF-α) and negative control group (DMEM).

RESULTS

The CD4⁺IL-25R⁺ cells and LGR5⁺IL-25R⁺ cells significantly increased in the colonic mucosa of active CD patients and UC patients compared with IBD patients in remission and healthy controls. The CD4⁺IL-25R⁺ cells reduced in peripheral blood of IBD patients, which was inversely correlated with inflammatory markers (ESR and CRP). CM facilitated the migration and proliferation of IEC-6 cells in the presence of TNF-α. The protein expression of AKT, p38 and ERK increased in IEC-6 cells after treatment with CM and TNF-α.

CONCLUSION

IL-25R is involved in Th-related mucosal inflammation and proliferation of intestinal stem cells in IBD. IL-25 enhances the capacity of MSC to induce intestinal epithelial cell regeneration, and MSC therapy with IL-25 may be a new direction for IBD treatment.

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

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

Adipose-derived stromal cells resemble bone marrow stromal cells in hepatocyte differentiation potential in vitro and in vivo

AIM

To investigate whether mesenchymal stem cells (MSCs) from adipose-derived stromal cells (ADSCs) and bone marrow stromal cells (BMSCs) have similar hepatic differentiation potential.

METHODS

Mouse ADSCs and BMSCs were isolated and cultured. Their morphological and phenotypic characteristics, as well as their multiple differentiation capacity were compared. A new culture system was established to induce ADSCs and BMSCs into functional hepatocytes. Reverse transcription polymerase chain reaction, Western blot, and immunofluorescence analyses were performed to identify the induced hepatocyte-like cells. CM-Dil-labeled ADSCs and BMSCs were then transplanted into a mouse model of CCl₄-induced acute liver failure. Fluorescence microscopy was used to track the transplanted MSCs. Liver function was tested by an automatic biochemistry analyzer, and liver tissue histology was observed by hematoxylin and eosin (HE) staining.

RESULTS

ADSCs and BMSCs shared a similar morphology and multiple differentiation capacity, as well as a similar phenotype (with expression of CD29 and CD90 and no expression of CD11b or CD45). Morphologically, ADSCs and BMSCs became round and epithelioid following hepatic induction. These two cell types differentiated into hepatocyte-like cells with similar expression of albumin, cytokeratin 18, cytokeratin 19, alpha fetoprotein, and cytochrome P450. Fluorescence microscopy revealed that both ADSCs and BMSCs were observed in the mouse liver at different time points. Compared to the control group, both the function of the injured livers and HE staining showed significant improvement in the ADSC- and BMSC-transplanted mice. There was no significant difference between the two MSC groups.

CONCLUSION

ADSCs share a similar hepatic differentiation capacity and therapeutic effect with BMSCs in an acute liver failure model. ADSCs may represent an ideal seed cell type for cell transplantation or a bio-artificial liver support system.

Interleukin-25 primed mesenchymal stem cells achieve better therapeutic effects on dextran sulfate sodium-induced colitis via inhibiting Th17 immune response and inducing T regulatory cell phenotype

AIM

This study aimed to investigate the anti-inflammatory mechanism of IL-25 mediated mesenchymal stem cells (MSC) treatment for inflammatory bowel disease (IBD) in a DSS-induced rat colitis model.

METHODS

Rats with DSS-induced colitis were divided into control and treatment groups: normal control group (rats fed with water), DSS group (rats fed with DSS solution), MSC group (DSS-treated rats injected intravenously with GFP-MSCs), IL-25-MSC group (DSS-treated rats injected intravenously with IL-25 primed GFP-MSCs), and mesalazine group (DSS-treated rats fed with mesalazine).

RESULTS

In IL-25-MSC group, therapeutic efficacy (clinical symptoms) was better than in MSC group, but comparable to mesalazine group. In IL-25-MSC group and mesalazine group, fewer infiltrating inflammatory cells and lower pathological score were observed in the intestine. The FOXP3⁺ cells and IL-4⁺ cells decreased, but IL-17A⁺ cells and IFN-γ⁺ cells increased in the peripheral blood and colonic mucosa after DSS induced colitis, and these phenomena were reversed by MSC or mesalazine treatment. IL-17A⁺ cells reduced and FOXP3⁺ cells increased in IL-25-MSC group as compared with MSC group. The expressions of Ki67 and LGR5 were significantly elevated in MSC treatment groups as compared with normal control group, DSS group, and mesalazine group. Definite GFP positive cells were not observed in the intestine of MSC-treated rats.

CONCLUSION

IL-25 primed MSCs exert improved therapeutic effects on the intestinal inflammation of IBD rats which may be related to the inhibition of Th17 immune response and induction of T Regulatory cell phenotype. Thus, IL-25 may be an attractive candidate for MSC-based therapy of IBD.

Stem cell therapy for abrogating stroke-induced neuroinflammation and relevant secondary cell death mechanisms

Ischemic stroke is a leading cause of death worldwide. A key secondary cell death mechanism mediating neurological damage following the initial episode of ischemic stroke is the upregulation of endogenous neuroinflammatory processes to levels that destroy hypoxic tissue local to the area of insult, induce apoptosis, and initiate a feedback loop of inflammatory cascades that can expand the region of damage. Stem cell therapy has emerged as an experimental treatment for stroke, and accumulating evidence supports the therapeutic efficacy of stem cells to abrogate stroke-induced inflammation. In this review, we investigate clinically relevant stem cell types, such as hematopoietic stem cells (HSCs), mesenchymal stem cells (MSCs), endothelial progenitor cells (EPCs), very small embryonic-like stem cells (VSELs), neural stem cells (NSCs), extraembryonic stem cells, adipose tissue-derived stem cells, breast milk-derived stem cells, menstrual blood-derived stem cells, dental tissue-derived stem cells, induced pluripotent stem cells (iPSCs), teratocarcinoma-derived Ntera2/D1 neuron-like cells (NT2N), c-mycER(TAM) modified NSCs (CTX0E03), and notch-transfected mesenchymal stromal cells (SB623), comparing their potential efficacy to sequester stroke-induced neuroinflammation and their feasibility as translational clinical cell sources. To this end, we highlight that MSCs, with a proven track record of safety and efficacy as a transplantable cell for hematologic diseases, stand as an attractive cell type that confers superior anti-inflammatory effects in stroke both in vitro and in vivo. That stem cells can mount a robust anti-inflammatory action against stroke complements the regenerative processes of cell replacement and neurotrophic factor secretion conventionally ascribed to cell-based therapy in neurological disorders.

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

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

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.

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 Therapeutic Efficacy of Tonsil-derived Mesenchymal Stem Cells in Dextran Sulfate Sodium-induced Acute Murine Colitis Model

Background/Aims

Mesenchymal stem cells (MSCs) are multipotent progenitor cells currently under investigation for its efficacy as the treatment for inflammatory bowel disease. In this study, we evaluated the efficacy of tonsil-derived mesenchymal stem cells (T-MSCs) as a novel source of mesenchymal stem cells and traced their localization in a murine model of acute colitis induced by dextran sulfate sodium (DSS).

Methods

C57BL/6 mice were randomly assigned to the following three groups: the normal control group, DSS colitis group (DSS+phosphate buffered saline), and T-MSC group (DSS+T-MSCs, 1×10⁶). The severity of colitis was assessed by determining the severity of symptoms of colitis, colon length, histopathologic grade, and levels of inflammatory cytokines. T-MSCs labeled with PKH26 were traced in vivo.

Results

The T-MSC group, compared with the DSS colitis group, showed a significantly lower disease activity index (11.3±1.5 vs. 8.3±1.9, p=0.015) at sacrifice and less reduction of body weight (-17.1±5.0% vs. -8.1±6.9%, p=0.049). In the T-MSC group, the histologic colitis score was significantly decreased compared with the DSS colitis group (22.6±3.8 vs. 17.0±3.4, p=0.039). IL-6 and IL-1β, the pro-inflammatory cytokines, were also significantly reduced after a treatment with T-MSCs. In vivo tracking revealed no PKH26-labelled T-MSCs in the colonic tissue of mice with acute colitis.

Conclusions

In the acute colitis model, we demonstrated that the administration of T-MSCs ameliorates inflammatory symptoms and histology. Moreover, the anti-inflammatory activities of T-MSCs were independent of gut homing.

Mesenchymal Stem Cell-Seeded Regenerated Silk Fibroin Complex Matrices for Liver Regeneration in an Animal Model of Acute Liver Failure

The main limitation of liver transplantation as a treatment for end-stage liver disease or acute liver failure is the scarcity of liver organ donors. To develop an alternative therapy for acute liver failure, mesenchymal stem cell (MSC)-seeded regenerated silk fibroin (RSF) matrices were evaluated in vitro and in vivo. Adipose-derived mesenchymal stem cells (ADSCs) and bone marrow-derived mesenchymal stem cells (BMSCs) were planted and grown on RSF scaffolds to form a scaffold complex. The RSF-MSC scaffold complex (the experimental group) and neat RSF scaffolds (the control group) were then placed onto the liver surface of mice induced by CCl₄ and detected after 5, 7, 14, 28, and 60 days. The growth and distribution of MSCs were tracked using fluorescence microscopy and live small animal fluorescence. Liver functions were tested using an automatic biochemistry analyzer. The histological kinetics of RSF complex and liver tissues were observed using hematoxylin & eosin staining. We found that MSCs exhibited good biocompatibility with RSF and differentiated to hepatocyte-like cells in vitro. Liver functions of the mice in the experimental group were significantly improved than that in the control group. Moreover, angiogenesis and hepatocyte-like cells were discovered in the RSF scaffolds in an animal model of acute liver failure on the fifth day and in the second month, respectively. The MSCs-RSF matrices show an obvious therapeutic ability for injured liver function of mice, which is more efficient than the neat RSF scaffolds.

Intralymphatic Administration of Adipose Mesenchymal Stem Cells Reduces the Severity of Collagen-Induced Experimental Arthritis

Mesenchymal stem cells (MSCs) are multipotent stromal cells with immunomodulatory properties. They have emerged as a very promising treatment for autoimmunity and inflammatory diseases such as rheumatoid arthritis. Previous studies have demonstrated that MSCs, administered systemically, migrate to lymphoid tissues associated with the inflammatory site where functional MSC-induced immune cells with a regulatory phenotype were increased mediating the immunomodulatory effects of MSCs. These results suggest that homing of MSCs to the lymphatic system plays an important role in the mechanism of action of MSCs in vivo. Thus, we hypothesized that direct intralymphatic (IL) (also referred as intranodal) administration of MSCs could be an alternative and effective route of administration for MSC-based therapy. Here, we report the feasibility and efficacy of the IL administration of human expanded adipose mesenchymal stem cells (eASCs) in a mouse model of collagen-induced arthritis (CIA). IL administration of eASCs attenuated the severity and progression of arthritis, reduced bone destruction and increased the levels of regulatory T cells (CD25⁺Foxp3⁺CD4⁺ cells) and Tr1 cells (IL10⁺CD4⁺), in spleen and draining lymph nodes. Taken together, these results indicate that IL administration of eASCs is very effective in modulating established CIA and may represent an alternative treatment modality for cell therapy with eASCs.

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.

Anti-Inflammatory and Anti-Oxidant Effects of p-Chloro-phenyl-selenoesterol on TNBS-Induced Inflammatory Bowel Disease in Mice

This study aims to investigate the protective effect of p-chloro-phenyl-selenoesterol [PCS; 0,2 mg/kg; 10 ml/kg i.g.) in colitis induced by 2,4,6-trinitrobenzene sulfonic acid [TNBS; 2 mg/100 µl 50% ethanol; intrarectally) in mice. Several parameters including weight, length, histological analyses determination, thiobarbituric acid reactive species, reactive species levels, superoxide dismutase, catalase, and myeloperoxidase (MPO) activity of colon were evaluated. The serum levels of tumor necrosis factor alpha [TNF-α) and interleukin 6 [IL-6) were also assessed. Treatment with PCS reduced the clinical and histopathologic severity of TNBS-induced colitis, characterized by colon length reduction and increased colon weight and microscopic intestinal inflammation. The therapeutic effects of PCS in this model were associated with significant decrease in proinflammatory cytokines TNF-α and IL-6 and decrease in MPO activity. Furthermore, combined with improvements in inflammatory parameters, treatment with the PCS was able to decrease oxidative stress and to prevent the decrease in antioxidant defenses in animals with TNBS-induced colitis. This finding suggests that PCS can improve experimental colitis in mice and it could be a potential therapeutic agent for the treatment of patients with IBD. J. Cell. Biochem. 118: 709-717, 2017. © 2016 Wiley Periodicals, Inc.

Toll-like receptor 3 pre-conditioning increases the therapeutic efficacy of umbilical cord mesenchymal stromal cells in a dextran sulfate sodium-induced colitis model

BACKGROUND AIMS

Immunomodulatory properties of human umbilical cord-derived mesenchymal stromal cells (UCMSCs) can be differentially modulated by toll-like receptors (TLR) agonists. Here, the therapeutic efficacy of short TLR3 and TLR4 pre-conditioning of UCMSCs was evaluated in a dextran sulfate sodium (DSS)-induced colitis in mice. The novelty of this study is that although modulation of human MSCs activity by TLRs is not a new concept, this is the first time that short TLR pre-conditioning has been carried out in a murine inflammatory model of acute colitis.

METHODS

C57BL/6 mice were exposed to 2.5% dextran sulfate sodium (DSS) in drinking water ad libitum for 7 days. At days 1 and 3, mice were injected intraperitoneally with 1 × 10(6) UCMSCs untreated or TLR3 and TLR4 pre-conditioned UCMSCs. UCMSCs were pre-conditioned with poly(I:C) for TLR3 and LPS for TLR4 for 1 h at 37°C and 5% CO2. We evaluated clinical signs of disease and body weights daily. At the end of the experiment, colon length and histological changes were assessed.

RESULTS

poly(I:C) pre-conditioned UCMSCs significantly ameliorated the clinical and histopathological severity of DSS-induced colitis compared with UCMSCs or LPS pre-conditioned UCMSCs. In contrast, infusion of LPS pre-conditioned UCMSCs significantly increased clinical signs of disease, colon shortening and histological disease index in DSS-induced colitis.

CONCLUSIONS

These results show that short in vitro TLR3 pre-conditioning with poly(I:C) enhances the therapeutic efficacy of UCMSCs, which is a major breakthrough for developing improved treatments to patients with inflammatory bowel disease.

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

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

Differential TLR activation of murine mesenchymal stem cells generates distinct immunomodulatory effects in EAE

Background

Recently, it has been observed that mesenchymal stem cells (MSCs) can modulate their immunoregulatory properties depending on the specific in-vitro activation of different Toll-like receptors (TLR), such as TLR3 and TLR4. In the present study, we evaluated the effect of polyinosinic:polycytidylic acid (poly(I:C)) and lipopolysaccharide (LPS) pretreatment on the immunological capacity of MSCs in vitro and in vivo.

Methods

C57BL/6 bone marrow-derived MSCs were pretreated with poly(I:C) and LPS for 1 hour and their immunomodulatory capacity was evaluated. T-cell proliferation and their effect on Th1, Th17, and Treg differentiation/activation were measured. Next, we evaluated the therapeutic effect of MSCs in an experimental autoimmune encephalomyelitis (EAE) model, which was induced for 27 days with MOG_35–55 peptide following the standard protocol. Mice were subjected to a single intraperitoneal injection (2 × 10⁶ MSCs/100 μl) on day 4. Clinical score and body weight were monitored daily by blinded analysis. At day 27, mice were euthanized and draining lymph nodes were extracted for Th1, Th17, and Treg detection by flow cytometry.

Results

Pretreatment of MSCs with poly(I:C) significantly reduced the proliferation of CD3⁺ T cells as well as nitric oxide secretion, an important immunosuppressive factor. Furthermore, MSCs treated with poly(I:C) reduced the differentiation/activation of proinflammatory lymphocytes, Th1 and Th17. In contrast, MSCs pretreated with LPS increased CD3⁺ T-cell proliferation, and induced Th1 and Th17 cells, as well as the levels of proinflammatory cytokine IL-6. Finally, we observed that intraperitoneal administration of MSCs pretreated with poly(I:C) significantly reduced the severity of EAE as well as the percentages of Th1 and Th17 proinflammatory subsets, while the pretreatment of MSCs with LPS completely reversed the therapeutic immunosuppressive effect of MSCs.

Conclusions

Taken together, these data show that pretreatment of MSCs with poly(I:C) improved their immunosuppressive abilities. This may provide an opportunity to better define strategies for cell-based therapies to autoimmune diseases.

Differential expression of Th17 cytokines in the colon of rats in different inflammatory periods of Crohn's disease

AIM: To observe the intestinal inflammatory status and the expression of interleukin (IL)-6, IL-17A, IL-21, and retinoid-related orphan nuclear receptor γt (RORγt) secreted by Th17 cells in colon tissues of rats with trinitro-benzene-sulfonic acid (TNBS) induced Crohn's disease.

METHODS: Thirty male rats were randomly divided into a normal control group and 1-, 2-, 3- and 4-wk model groups. Morphological observation and HE staining were used to assess the degree of damage to the colonic mucosa. Fluorescence quantitative PCR, immunohistochemical method and other techniques were used to observe the expression of RORγt and IL-17A in rat colonic mucosa, and ELISA method was used to detect the contents of IL-6 and IL-21 in serum.

RESULTS: The level of IL-17A mRNA in rat colon decreased at the first induction with TNBS, but the levels of IL-17A mRNA and protein obviously increased (P < 0.05) at 3 wk and reached the highest after the fourth induction. The expression of RORγt protein gradually increased after induction (P < 0.05), and reached the highest at the fourth induction (P < 0.05). The contents of IL-6 and IL-21 in serum obviously increased from the first week (P < 0.01), reaching the highest at the fourth week. The colon general morphological score and tissue damage score of model rats obviously increased (P < 0.01).

CONCLUSION: During the process of Crohn's disease induced with TNBS, the contents of IL-6, IL-17A, IL-21, and RORγt secreted by Th17 cells gradually increased and the degree of colonic inflammation gradually exacerbated.

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.

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.

Neuroprotective Potential of Mesenchymal Stem Cell-Based Therapy in Acute Stages of TNBS-Induced Colitis in Guinea-Pigs

Background & Aims

The therapeutic benefits of mesenchymal stem cells (MSCs), such as homing ability, multipotent differentiation capacity and secretion of soluble bioactive factors which exert neuroprotective, anti-inflammatory and immunomodulatory properties, have been attributed to attenuation of autoimmune, inflammatory and neurodegenerative disorders. In this study, we aimed to determine the earliest time point at which locally administered MSC-based therapies avert enteric neuronal loss and damage associated with intestinal inflammation in the guinea-pig model of colitis.

Methods

At 3 hours after induction of colitis by 2,4,6-trinitrobenzene-sulfonate (TNBS), guinea-pigs received either human bone marrow-derived MSCs, conditioned medium (CM), or unconditioned medium by enema into the colon. Colon tissues were collected 6, 24 and 72 hours after administration of TNBS. Effects on body weight, gross morphological damage, immune cell infiltration and myenteric neurons were evaluated. RT-PCR, flow cytometry and antibody array kit were used to identify neurotrophic and neuroprotective factors released by MSCs.

Results

MSC and CM treatments prevented body weight loss, reduced infiltration of leukocytes into the colon wall and the myenteric plexus, facilitated repair of damaged tissue and nerve fibers, averted myenteric neuronal loss, as well as changes in neuronal subpopulations. The neuroprotective effects of MSC and CM treatments were observed as early as 24 hours after induction of inflammation even though the inflammatory reaction at the level of the myenteric ganglia had not completely subsided. Substantial number of neurotrophic and neuroprotective factors released by MSCs was identified in their secretome.

Conclusion

MSC-based therapies applied at the acute stages of TNBS-induced colitis start exerting their neuroprotective effects towards enteric neurons by 24 hours post treatment. The neuroprotective efficacy of MSC-based therapies can be exerted independently to their anti-inflammatory effects.

Non-drug treatment of inflammatory bowel disease

Inflammatory bowel disease (IBD) is an idiopathic, chronic, nonspecific inflammatory disease. IBD is comprised of two major types, ulcerative colitis (UC) and Crohn's disease (CD), and is hard to be cured. Currently, aminosalicylic acid preparations, corticosteroids and immunosuppressant drugs are the main treatments for the disease, but there exists poor drug efficacy in some cases, and patients are prone to side effects. Biological agents greatly improve the efficacy, but for a small number of refractory patients, comprehensive intervention containing non-drug treatments is needed. Non-drug treatments like fecal microbiota transplantation (FMT), stem cell transplantation, and granulocyte and monocyte apheresis (GMA) have shown enormous potential for the treatment of IBD, and have become a hot spot of IBD treatment research in recent years. In this paper, we review the non-drug treatments for IBD, in order to broaden the horizons of clinicians in the treatment of IBD.

Bone mesenchymal stem cells overexpressing FGF4 contribute to liver regeneration in an animal model of liver cirrhosis

It is recognized that Fibroblast Growth Factor 4 (FGF-4) could not only increase the proliferation of bone marrow mesenchymal stem cells (BMSCs), but also induce BMSCs into hepatocyte-like cells in vitro. However, the role of FGF4 played in liver regeneration in vivo is unclear. This study constructed FGF4 overexpressing BMSCs and then transplanted them into cirrhotic rats to investigate the role of FGF4 played in liver regeneration. The results showed that FGF4 promoted the location of the BMSCs only at the early stage, and more proliferating cell nuclear antigen (PCNA), epithelial cell adhesion molecule (EpCAM) and Jagged-1 positive hepatocytes were found in the cirrhotic rats. This study indicated that FGF4 transduced BMSCs contributed to liver regeneration might by the transplanted microenvironment.

Effects of autologous bone marrow-derived stem cell mobilization on acute tubular necrosis and cell apoptosis in rats

The aim of this study was to investigate the effects of stem cell factor (SCF) and granulocyte colony-stimulating factor (G-CSF) on bone marrow-derived stem cell (BMSC) mobilization in rat models of renal ischemia/reperfusion (I/R) injury. In addition, the effects of SCF and G-CSF on cellular apoptosis were explored in order to determine the protective mechanism of the two factors against renal I/R injury. A unilateral renal I/R injury model was established for the model and treatment groups. The treatment and treatment control groups were subcutaneously injected with SCF (200 µg/kg/day) and G-CSF (50 µg/kg/day) 24 h after the establishment of the model for five consecutive days. The total number of leukocytes in the peripheral blood and the cellular percentages of cluster of differentiation (CD)34⁺, renal CD34⁺ and apoptotic cells were detected. The total number of leukocytes in the peripheral blood and the percentages of CD34⁺ cells in the treatment and treatment control groups reached maximum levels on the fifth postoperative day and were significantly higher than those in the normal control and model groups. The number of renal CD34⁺ cells in the treatment group was significantly increased compared with that in the treatment control and model groups. The apoptotic indices (AIs) of the model and treatment groups were higher than those of the normal control and treatment control groups. The AI of the model group was significantly higher than that of the treatment group. In conclusion, the combined application of SCF and G-CSF can mobilize sufficient numbers of BMSCs and cause cellular 'homing' to the injured site, thus inhibiting apoptosis and promoting the repair of renal tubular injury.

Expression of Wnt and Notch signaling pathways in inflammatory bowel disease treated with mesenchymal stem cell transplantation: evaluation in a rat model

INTRODUCTION

The purpose of this study was to investigate the expression of Wnt and Notch signaling pathway-related genes in inflammatory bowel disease (IBD) treated with mesenchymal stem cell transplantation (MSCT).

METHODS

TNBS (2,4,6-trinitrobenzene sulfonic acid) was used to establish IBD in a rat model. Mesenchymal stem cells (MSCs) were transplanted via tail vein transfusion. Saline water was used in a control group. The expression of Wnt and Notch main signaling molecules was screened by gene chips and verified by quantitative reverse transcription-polymerase chain reaction in the IBD rat model on day 14 and day 28 after transplantation.

RESULTS

The IBD rat models were successfully established and MSCs were transplanted into those models. Genome-wide expression profile chips identified a total of 388 differentially expressive genes, of which 191 were upregulated and 197 were downregulated in the MSC-transplanted group in comparison with the IBD control group. Real-time quantitative polymerase chain reaction results showed that the level of Olfm4 mRNA expression in the IBD group (2.54±0.20) was significantly increased compared with the MSCT group (1.39±0.54) and the normal group (1.62±0.25) (P <0.05). The Wnt3a mRNA was more highly expressed in IBD rats (2.92±0.94) and decreased in MSCT rats (0.17±0.63, P <0.05). The expression of GSK-3β mRNA was decreased in the setting of inflammation (0.65±0.04 versus 1.00±0.01 in normal group, P <0.05) but returned to normal levels after MSCT (0.81±0.17). The expression of β-catenin was observed to increase in IBD tissues (1.76±0.44) compared with normal tissues (1.00±0.01, P <0.05), but no difference was found in the MSCT group (1.12±0.36). Wnt11 declined at 14 days and returned to normal levels at 28 days in the IBD group; in comparison, a significantly lower expression was found in MSCT rats. There were no differences in the expression of Fzd3, c-myc, TCF4, and Wnt5a in inflammation, but all of those genes declined after MSCT treatment.

CONCLUSIONS

The canonical Wnt and Notch signaling pathways are activated in IBD and may be suppressed by stem cell transplantation to differentiate into intestinal epithelium after MSCT. Moreover, the non-canonical Wnt signaling may be inhibited by canonical Wnt signaling in the setting of inflammation and may also be suppressed by MSCT.

Lactobacillus acidophilus suppresses colitis-associated activation of the IL-23/Th17 axis

The aim of this paper is to determine the modulatory effects of Lactobacillus acidophilus on the IL-23/Th17 immune axis in experimental colitis. DSS-induced mouse models of UC were to be saline, hormones, and different concentrations of Lactobacillus acidophilus intervention. The expression of interleukin- (IL-) 17, tumor necrosis factor α (TNFα), IL-23, transforming growth factor β1 (TGFβ1), signal transducer and activator of transcription 3 (STAT3), and phosphorylated (p)-STAT3 was examined by RT-PCR, Western blotting, and immunohistochemical analysis. And the results showed that administration of L. acidophilus suppressed Th17 cell-mediated secretion of proinflammatory cytokine IL-17 through downregulation of IL-23 and TGFβ1 expression and downstream phosphorylation of p-STAT3.

Stem cell therapy in inflammatory bowel disease: A promising therapeutic strategy?

Inflammatory bowel diseases are inflammatory, chronic and progressive diseases of the intestinal tract for which no curative treatment is available. Research in other fields with stem cells of different sources and with immunoregulatory cells (regulatory T-lymphocytes and dendritic T-cells) opens up new expectations for their use in these diseases. The goal for stem cell-based therapy is to provide a permanent cure. To achieve this, it will be necessary to obtain a cellular product, original or genetically modified, that has a high migration capacity and homes into the intestine, has high survival after transplantation, regulates the immune reaction while not being visible to the patient’s immune system, and repairs the injured tissue.

Transplantation of bone marrow-derived mesenchymal stem cells facilitates epithelial repair and relieves the impairment of gastrointestinal function in a rat model of enteritis

BACKGROUND

To examine whether the bone marrow-derived MSCs (BM-MSCs) could facilitate epithelial repair and thereby reduce impairment of gastrointestinal structure and function in chronic murine enteritis induced by indomethacin (IDM).

METHODS

MSCs were isolated from young Sprague-Dawley rats. After in vitro expansion and characterization, BM-MSCs were labelled with the fluorescent dye PKH26 and transfused, via the tail veins, into rats with enteritis induced by IDM. The controls were infused with sterile saline. The homing and differentiation of the transplanted BM-MSCs were tracked by means of fluorescent staining. The clinical symptoms of the IDM-treated rats were assessed, and the macroscopic and microscopic histological evaluations of the intestines were performed.

RESULTS

Compared to controls that received saline infusion, BM-MSCs treated rats showed lower scores of weight loss, stool consistency, and stool blood. The PKH26-labelled cells resided at the injured intestine, where they co-localize with the proliferating cell nuclear antigen (PCNA), Lgr-5, and Msi-1. The BM-MSCs treated rats showed significantly higher intestinal villi with larger areas relative to the saline-treated rats.

CONCLUSION

The transplanted BM-MSCs are able to recognize the injured intestine, where they proliferate and transdifferentiate into intestinal stem cells which repair the injured intestinal tissues. Therefore, BM-MSCs are able to relieve the impairment of gastrointestinal function in IMD-treated rats.

Effect of human bone marrow mesenchymal stromal cells on cytokine production by peripheral blood naive, memory, and effector T cells

Introduction

The different distribution of T cells among activation/differentiation stages in immune disorders may condition the outcome of mesenchymal stromal cell (MSC)-based therapies. Indeed, the effect of MSCs in the different functional compartments of T cells is not completely elucidated.

Methods

We investigated the effect of human bone marrow MSCs on naturally occurring peripheral blood functional compartments of CD4⁺ and CD8⁺ T cells: naive, central memory, effector memory, and effector compartments. For that, mononuclear cells (MNCs) stimulated with phorbol myristate acetate (PMA) plus ionomycin were cultured in the absence/presence of MSCs. The percentage of cells expressing tumor necrosis factor-alpha (TNF-α), interferon gamma (IFNγ), and interleukin-2 (IL-2), IL-17, IL-9, and IL-6 and the amount of cytokine produced were assessed by flow cytometry. mRNA levels of IL-4, IL-10, transforming growth factor-beta (TGF-β), and cytotoxic T-lymphocyte-associated protein 4 (CTLA4) in purified CD4⁺ and CD8⁺ T cells, and phenotypic and mRNA expression changes induced by PMA + ionomycin stimulation in MSCs, were also evaluated.

Results

MSCs induced the reduction of the percentage of CD4⁺ and CD8⁺ T cells producing TNF-α, IFNγ, and IL-2 in all functional compartments, except for naive IFNγ⁺CD4⁺ T cells. This inhibitory effect differentially affected CD4⁺ and CD8⁺ T cells as well as the T-cell functional compartments; remarkably, different cytokines showed distinct patterns of inhibition regarding both the percentage of producing cells and the amount of cytokine produced. Likewise, the percentages of IL-17⁺, IL-17⁺TNF-α⁺, and IL-9⁺ within CD4⁺ and CD8⁺ T cells and of IL-6⁺CD4⁺ T cells were decreased in MNC-MSC co-cultures. MSCs decreased IL-10 and increased IL-4 mRNA expression in stimulated CD4⁺ and CD8⁺ T cells, whereas TGF-β was reduced in CD8⁺ and augmented in CD4⁺ T cells, with no changes for CTLA4. Finally, PMA + ionomycin stimulation did not induce significant alterations on MSCs phenotype but did increase indoleamine-2,3-dioxygenase (IDO), inducible costimulatory ligand (ICOSL), IL-1β, IL-8, and TNF-α mRNA expression.

Conclusions

Overall, our study showed that MSCs differentially regulate the functional compartments of CD4⁺ and CD8⁺ T cells, which may differentially impact their therapeutic effect in immune disorders. Furthermore, the influence of MSCs on IL-9 expression can open new possibilities for MSC-based therapy in allergic diseases.

Electronic supplementary material

The online version of this article (doi:10.1186/scrt537) contains supplementary material, which is available to authorized users.

Immunoregulation of Bone Marrow-Derived Mesenchymal Stem Cells on the Chronic Cigarette Smoking-Induced Lung Inflammation in Rats

Impact of bone mesenchymal stem cell (BMSC) transfusion on chronic smoking-induced lung inflammation is poorly understood. In this study, a rat model of smoking-related lung injury was induced and the rats were treated with vehicle or BMSCs for two weeks. Different subsets of CD4+ T cells, cytokines, and anti-elastin in the lungs as well as the lung injury were characterized. Serum and lung inducible nitric oxide synthase (iNOS) and STAT5 phosphorylation in lymphocytes from lung tissue were also analyzed. Results indicated that transfusion of BMSCs significantly reduced the chronic smoking-induced lung injury, inflammation, and levels of lung anti-elastin in rats. The frequency of Th1 and Th17 cells and the levels of IL-2, IL-6, IFN-γ, TNF-α, IL-17, IP-10, and MCP-1 increased, but the frequency of Tregs and IL-10 decreased. Transfusion of BMSCs significantly modulated the imbalance of immune responses by mitigating chronic smoking-increased Th1 and Th17 responses, but enhancing Treg responses in the lungs of rats. Transfusion of BMSCs limited chronic smoking-related reduction in the levels of serum and lung iNOS and mitigated smoking-induced STAT5 phosphorylation in lymphocytes from lung tissue. BMSCs negatively regulated smoking-induced autoimmune responses in the lungs of rats and may be promising for the intervention of chronic smoking-related lung injury.

Classical and recent advances in the treatment of inflammatory bowel diseases

Crohn's disease (CD) and ulcerative colitis (UC) are intestinal disorders that comprise the inflammatory bowel diseases (IBD). These disorders have a significant effect on the quality of life of affected patients and the increasing number of IBD cases worldwide is a growing concern. Because of the overall burden of IBD and its multifactorial etiology, efforts have been made to improve the medical management of these inflammatory conditions. The classical therapeutic strategies aim to control the exacerbated host immune response with aminosalicylates, antibiotics, corticosteroids, thiopurines, methotrexate and anti-tumor necrosis factor (TNF) biological agents. Although successful in the treatment of several CD or UC conditions, these drugs have limited effectiveness, and variable responses may culminate in unpredictable outcomes. The ideal therapy should reduce inflammation without inducing immunosuppression, and remains a challenge to health care personnel. Recently, a number of additional approaches to IBD therapy, such as new target molecules for biological agents and cellular therapy, have shown promising results. A deeper understanding of IBD pathogenesis and the availability of novel therapies are needed to improve therapeutic success. This review describes the overall key features of therapies currently employed in clinical practice as well as novel and future alternative IBD treatment methods.

Exogenous IL-4-expressing bone marrow mesenchymal stem cells for the treatment of autoimmune sensorineural hearing loss in a guinea pig model

Bone marrow mesenchymal stem cells (BMSCs) expressing recombinant IL-4 have the potential to remediate inflammatory diseases. We thus investigated whether BMSCs expressing exogenous IL-4 could alleviate autoimmune sensorineural hearing loss. BMSCs isolated from guinea pigs were transfected with recombinant lentivirus expressing IL-4. A total of 33 animals were divided into three groups. Group A received scala tympani injection of IL-4-expressing BMSCs, and Group B received control vector-expressing BMSCs, and Group C received phosphate-buffered saline. The distribution of implanted BMSCs in the inner ears was assessed by immunohistochemistry and fluorescence microscopy. Auditory brain-stem response (ABR) was monitored to evaluate the auditory changes. Following BMSCs transplantation, the threshold levels of ABR wave III decreased in Groups A and B and significant differences were observed between these two groups (P < 0.05). Transplanted BMSCs distributed in the scala tympani and scala vestibuli. In some ears with hearing loss, there was a decrease in the number of spiral ganglion cells and varying degrees of endolymphatic hydrops or floccule. Following transplantation, the lentivirus-infected BMSCs migrated to the inner ear and produced IL-4. Our results demonstrate that, upon transplantation, BMSCs and BMSCs expressing recombinant IL-4 have the ability to remediate the inflammatory injury in autoimmune inner ear diseases.

Role of Th17 Cells in the Pathogenesis of Human IBD

The gastrointestinal tract plays a central role in immune system, being able to mount efficient immune responses against pathogens, keeping the homeostasis of the human gut. However, conditions like Crohn's disease (CD) or ulcerative colitis (UC), the main forms of inflammatory bowel diseases (IBD), are related to an excessive and uncontrolled immune response against normal microbiota, through the activation of CD4(+) T helper (Th) cells. Classically, IBD was thought to be primarily mediated by Th1 cells in CD or Th2 cells in UC, but it is now known that Th17 cells and their related cytokines are crucial mediators in both conditions. Th17 cells massively infiltrate the inflamed intestine of IBD patients, where they produce interleukin- (IL-) 17A and other cytokines, triggering and amplifying the inflammatory process. However, these cells show functional plasticity, and they can be converted into either IFN- γ producing Th1 cells or regulatory T cells. This review will summarize the current knowledge regarding the regulation and functional role of Th17 cells in the gut. Deeper insights into their plasticity in inflammatory conditions will contribute to advancing our understanding of the mechanisms that regulate mucosal homeostasis and inflammation in the gut, promoting the design of novel therapeutic approaches for IBD.

Therapy with stem cells in inflammatory bowel disease

Inflammatory bowel disease (IBD) affects a part of the young population and has a strong impact upon quality of life. The underlying etiology is not known, and the existing treatments are not curative. Furthermore, a significant percentage of patients are refractory to therapy. In recent years there have been great advances in our knowledge of stem cells and their therapeutic applications. In this context, autologous hematopoietic stem cell transplantation (HSCT) has been used in application to severe refractory Crohn’s disease (CD), with encouraging results. Allogenic HSCT would correct the genetic defects of the immune system, but is currently not accepted for the treatment of IBD because of its considerable risks. Mesenchymal stem cells (MSCs) have immune regulatory and regenerative properties, and low immunogenicity (both autologous and allogenic MSCs). Based on these properties, MSCs have been used via the systemic route in IBD with promising results, though it is still too soon to draw firm conclusions. Their local administration in perianal CD is the field where most progress has been made in recent years, with encouraging results. The next few years will be decisive for defining the role of such therapy in the management of 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.