Stem cells as potential therapeutic targets for inflammatory bowel disease

Immunological response of polysaccharide nanogel-incorporating PEG hydrogels in an in vivo diabetic model

Cell-based therapies hold significant advantages in comparison with the traditional drug-based or injection-based treatments. However, for long-term functional cellular implants, immune acceptance must be established. To accomplish the acceptance of the implanted cells, various biomaterial systems have been studied. Nanogels have shown great potential for modulation of cellular microenvironments, acting as a physical barrier between the immune system and the implant. However, internalization of nano-scale materials by implanted cells is not desirable and is yet to be overcome. In this study, we incorporated acrylate modified cholesterol-bearing pullulan (CHPOA) nanogels into poly (ethylene glycol) diacrylate (PEGDA) hydrogels through covalent crosslinking, where we used visible light-induced photopolymerization. We characterized morphology and swelling properties of CHPOA incorporated PEG composite hydrogels using FE-SEM and gravimetric analysis. Also, we investigated the biocompatibility properties of composite hydrogels in vivo, where we used both healthy and diabetic mice. We induced diabetes in mice using a low dose streptozotocin (STZ) injections and implanted composite hydrogels in both diabetic and healthy mice through subcutaneous route. Immune cell infiltration of the retrieved tissue was examined through histological analysis, where we observed minimum immune response levels of 0-2 rareness, according to ISO standard of biological evaluation of medical devices. Our observation suggests that the composite hydrogel developed here can be used to introduce nanostructured domains into bulk hydrogels and that this system has potential to be used as immunologically acceptable composite material in cellular therapy without internalization of nanoparticles.

The Autophagy Protein Pacer Positively Regulates the Therapeutic Potential of Mesenchymal Stem Cells in a Mouse Model of DSS-Induced Colitis

Mesenchymal stem cells (MSC) have emerged as a promising tool to treat inflammatory diseases, such as inflammatory bowel disease (IBD), due to their immunoregulatory properties. Frequently, IBD is modeled in mice by using dextran sulfate sodium (DSS)-induced colitis. Recently, the modulation of autophagy in MSC has been suggested as a novel strategy to improve MSC-based immunotherapy. Hence, we investigated a possible role of Pacer, a novel autophagy enhancer, in regulating the immunosuppressive function of MSC in the context of DSS-induced colitis. We found that Pacer is upregulated upon stimulation with the pro-inflammatory cytokine TNFα, the main cytokine released in the inflammatory environment of IBD. By modulating Pacer expression in MSC, we found that Pacer plays an important role in regulating the autophagy pathway in this cell type in response to TNFα stimulation, as well as in regulating the immunosuppressive ability of MSC toward T-cell proliferation. Furthermore, increased expression of Pacer in MSC enhanced their ability to ameliorate the symptoms of DSS-induced colitis in mice. Our results support previous findings that autophagy regulates the therapeutic potential of MSC and suggest that the augmentation of autophagic capacity in MSC by increasing Pacer levels may have therapeutic implications for IBD.

Targeting Enteric Neurons and Plexitis for the Management of Inflammatory Bowel Disease

Ulcerative colitis (UC) and Crohn's disease (CD) are pathological conditions with an unknown aetiology that are characterised by severe inflammation of the intestinal tract and collectively referred to as inflammatory bowel disease (IBD). Current treatments are mostly ineffective due to their limited efficacy or toxicity, necessitating surgical resection of the affected bowel. The management of IBD is hindered by a lack of prognostic markers for clinical inflammatory relapse. Intestinal inflammation associates with the infiltration of immune cells (leukocytes) into, or surrounding the neuronal ganglia of the enteric nervous system (ENS) termed plexitis or ganglionitis. Histological observation of plexitis in unaffected intestinal regions is emerging as a vital predictive marker for IBD relapses. Plexitis associates with alterations to the structure, cellular composition, molecular expression and electrophysiological function of enteric neurons. Moreover, plexitis often occurs before the onset of gross clinical inflammation, which may indicate that plexitis can contribute to the progression of intestinal inflammation. In this review, the bilateral relationships between the ENS and inflammation are discussed. These include the effects and mechanisms of inflammation-induced enteric neuronal loss and plasticity. Additionally, the role of enteric neurons in preventing antigenic/pathogenic insult and immunomodulation is explored. While all current treatments target the inflammatory pathology of IBD, interventions that protect the ENS may offer an alternative avenue for therapeutic intervention.

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

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

Intercellular adhesion molecule-1 enhances the therapeutic effects of MSCs in a dextran sulfate sodium-induced colitis models by promoting MSCs homing to murine colons and spleens

Background

To investigate the therapeutic effect of intercellular adhesion molecule (ICAM)-1-modified mesenchymal stem cells (MSCs) in a mouse model of inflammatory bowel disease (IBD) induced by dextran sulfate sodium.

Methods

Primary MSCs and ICAM-1-overexpressing MSCs (C3 cells) were generated in vitro. The IBD mouse model was induced with drinking water containing dextran sulfate sodium for 7 days. For stem cell therapy, mice were randomly assigned to six experimental groups: the control group, IBD group, primary MSC group, C3 group, C3-vector group, and C3-ICAM-1 group. Mice were given a single injection of 1 × 10⁶ primary MSCs or gene-modified MSCs via the tail vein on day 3 of DDS administration. The general conditions of the mice in each group were observed. Additionally, the pathological changes in the colon were observed and scored. Primary MSCs and gene-modified MSCs were stained with the fluorescent dye CM-DIL before injection into the tail vein of mice. The distribution of infused cells in IBD mice was observed in frozen sections. Mechanistically, the polarization of Th1, Th2, Th17, and regulatory T cells (Tregs) in the spleen was determined by flow cytometry. Moreover, the mRNA expression levels of IBD-related immune factors in splenocytes were measured by quantitative PCR.

Results

A single injection of MSCs promoted general recovery and reduced pathological damage in IBD mice. Additionally, ICAM-1-overexpressing MSCs had stronger therapeutic effects than ICAM-1^low MSCs. Furthermore, the in vivo distribution analysis results indicated that a higher number of ICAM-1-overexpressing MSCs homed to the colon and spleen of IBD mice. Moreover, the delivery of ICAM-1 overexpressing MSCs decreased the numbers of Th1 and Th17 cells but increased the number of Tregs in the spleen of IBD mice. The quantitative PCR analysis results revealed that an infusion of ICAM-1-overexpressing MSCs influenced the expression of spleen-derived immune factors by remarkably reducing the mRNA levels of IFN-γ and IL-17A and increasing the mRNA level of Foxp3.

Conclusions

Our results demonstrate that ICAM-1-modified mesenchymal stem cells (MSCs) remarkably alleviate inflammatory damage in IBD mice by promoting MSC homing to the target and immune organs. The findings suggest that ICAM-1 is required to maintain the therapeutic effects of MSCs in IBD treatment and identified a novel role of ICAM-1 in inflammatory diseases.

Electronic supplementary material

The online version of this article (10.1186/s13287-019-1384-9) contains supplementary material, which is available to authorized users.

PD-L1 is required for human endometrial regenerative cells-associated attenuation of experimental colitis in mice

Endometrial regenerative cells (ERCs) are easily isolated from menstrual blood, and can be cultured in large amounts. Although, ERCs can ameliorate DSS-induced colitis in mice, the molecular mechanism underlying ERCs-mediated immunosuppression is unclear. This study was aimed to assess the function of PD-L1 expressed on ERCs in colitis attenuation. ERCs with and without anti-PD-L1 mAb-pretreatment were administered to mice by injection at 2, 5 and 8 days after colitis induction by DSS treatment. Blood, spleen and colon samples were obtained 15 days post-DSS-induction. Then, clinicopathological alterations, cytokine levels, immune cell types and cell tracking were assessed. ERCs or ERCs preincubated with anti-PD-L1 antibody were co-cultured with splenocytes, whose phenotypes was analyzed by flow cytometry. We found that PD-L1 on ERCs was upregulated by IFN-γ stimulation. The transplanted PKH26-labeled ERCs were engrafted to the lung, liver, spleen and injured colon. Interestingly, ERC-based therapy markedly attenuated mouse colitis, but blockade of PD-L1 on ERCs with a specific monoclonal antibody conferred severe colitis to the animals. These effects of PD-L1 inhibition on colitis were associated with reduced amounts of pro-inflammatory cytokines and infiltrated immune cells, including CD3⁺CD4⁺ T lymphocytes, CD3⁺CD8⁺ T lymphocytes, CD11c⁺MHC-II⁺ Dendritic cells and F4/80⁺ macrophages, both in vivo and in vitro, as well as with elevated levels of anti-inflammatory cytokines and regulatory immune cells, including CD4⁺CD25⁺Foxp3⁺ Tregs and F4/80⁺CD206⁺ macrophages. These findings demonstrated that ERCs-based treatment promotes immune tolerance in mouse colitis, in association with PD-L1, thus indicating that PD-L1 modulates immunosuppression by ERCs.

Mesenchymal Stem Cells for Perianal Crohn's Disease

Perianal fistulizing Crohn’s disease (PFCD) is associated with significant morbidity and might negatively impact the quality of life of CD patients. In the last two decades, the management of PFCD has evolved in terms of the multidisciplinary approach involving gastroenterologists and colorectal surgeons. However, the highest fistula healing rates, even combining surgical and anti-TNF agents, reaches 50% of treated patients. More recently, the administration of mesenchymal stem cells (MSCs) have shown notable promising results in the treatment of PFCD. The aim of this review is to describe the rationale and the possible mechanism of action of MSC application for PFCD and the most recent results of randomized clinical trials. Furthermore, the unmet needs of the current administration process and the expected next steps to improve the outcomes will be addressed.

Safety and tracking of intrathecal allogeneic mesenchymal stem cell transplantation in healthy and diseased horses

Background

It is currently unknown if the intrathecal administration of a high dose of allogeneic mesenchymal stem cells (MSCs) is safe, how MSCs migrate throughout the vertebral canal after intrathecal administration, and whether MSCs are able to home to a site of injury. The aims of the study were: 1) to evaluate the safety of intrathecal injection of 100 million allogeneic adipose-derived MSCs (ASCs); 2) to assess the distribution of ASCs after atlanto-occipital (AO) and lumbosacral (LS) injection in healthy horses; and 3) to determine if ASCs homed to the site of injury in neurologically diseased horses.

Methods

Six healthy horses received 100 × 10⁶ allogeneic ASCs via AO (n = 3) or LS injection (n = 3). For two of these horses, ASCs were radiolabeled with technetium and injected AO (n = 1) or LS (n = 1). Neurological examinations were performed daily, and blood and cerebrospinal fluid (CSF) were evaluated prior to and at 30 days after injection. Scintigraphic images were obtained immediately postinjection and at 30 mins, 1 h, 5 h, and 24 h after injection. Three horses with cervical vertebral compressive myelopathy (CVCM) received 100 × 10⁶ allogeneic ASCs labeled with green fluorescent protein (GFP) via AO injection and were euthanized 1–2 weeks after injection for a full nervous system necropsy. CSF parameters were compared using a paired student’s t test.

Results

There were no significant alterations in blood, CSF, or neurological examinations at any point after either AO or LS ASC injections into healthy horses. The radioactive signal could be identified all the way to the lumbar area after AO ASC injection. After LS injection, the signal extended caudally but only a minimal radioactive signal extended further cranially. GFP-labeled ASCs were not present at the site of disease at either 1 or 2 weeks following intrathecal administration.

Conclusions

The intrathecal injection of allogeneic ASCs was safe and easy to perform in horses. The AO administration of ASCs resulted in better distribution within the entire subarachnoid space in healthy horses. ASCs could not be found after 7 or 15 days of injection at the site of injury in horses with CVCM.

Electronic supplementary material

The online version of this article (10.1186/s13287-018-0849-6) contains supplementary material, which is available to authorized users.

Umbilical cord blood mononuclear cell therapy induces clinical remission of steroid-dependent or -resistant ulcerative colitis patients

To compare the efficacy and safety of umbilical cord blood mononuclear cells (CBMNC) and azathioprine (AZA) in the treatment of patients with steroid-dependent or -resistant ulcerative colitis. One hundred and six patients diagnosed with steroid-dependent or -resistant ulcerative colitis were studied retrospectively, including 36 patients treated with CBMNC and 70 treated with AZA. To reduce confounding bias due to retrospective nature of this study, the propensity score matching system was applied to equipoise the pretreatment data of two groups. After matching, 35 matched pairs (1:1) were created. The ratios of clinical remission, clinical response and endoscopic mucosal healing, Mayo score, and major complications were compared between two groups at weeks 8, 16, and 36 after treatment. The results demonstrated that the ratios of clinical remission (80% vs. 57%, P < 0.05) and mucosal healing (74% vs. 51%, P < 0.05) were significantly higher in CBMNC-treated patients compared with those in AZA-treated patients at week 8. The erythrocyte sedimentation rate was significantly decreased in CBMNC group compared with that in AZA-treated group (14.5 ± 3.9 mm/h vs. 18.0 ± 5.7 mm/h, P < 0.01) at week 8. In AZA group, 2 patients had neutropenia and 3 patients had elevated alanine aminotransferase levels, whereas no obvious side-effects were observed in CBMNC-treated group. Our results reveal that CBMNC therapy appears to be an effective and safe strategy for patients with steroid-dependent or -resistant ulcerative colitis. Further prospective studies are needed to define the potential roles and mechanisms of CBMNC in the treatment of refractory ulcerative colitis.

Inflammatory Bowel Diseases and Fermentable Oligosaccharides, Disaccharides, Monosaccharides, and Polyols: An Overview

Inflammatory bowel diseases (IBDs) are mainly represented by ulcerative colitis and Crohn's disease, and the increase in the incidence tends to follow the rapid industrialization and lifestyle of modern societies. FODMAP (fermentable oligosaccharides, disaccharides, monosaccharides, and polyols) consist of molecules that are poorly absorbed in the small intestine and are fermented by bacteria in the colon leading to symptoms such as bloating, flatulence, diarrhea, and abdominal pain. Reduction of the ingestion of FODMAP could reduce the symptoms and improve the quality of life. This review aimed to summarize some important aspects of IBD and evaluate the effects of this diet on this inflammatory condition. Studies including the term FODMAP (and similar terms) and IBD were selected for this review (MEDLINE database was used PubMed/PMC). A low FODMAP diet may be an effective tool to the management of the common abdominal symptoms in patients with functional gastrointestinal symptoms once these molecules trigger these symptoms. This diet may also reduce the expression of pro-inflammatory markers such as C-reactive protein and fecal calprotectin and may interfere with the microbiome and its metabolites. The use of a low FODMAP diet can bring benefits to the IBD patients, but may also modify their nutritional status. Thus it should be utilized in appropriated conditions, and dietary supplements should be necessary to avoid deficiencies that could be caused by a low FODMAP diet over long periods. We suggest that further investigations are required to elucidate when and how to apply the FODMAP diet in IBD patients.

Local application of adipose-derived mesenchymal stem cells supports the healing of fistula: prospective randomised study on rat model of fistulising Crohn's disease

OBJECTIVE

Local application of adipose-derived mesenchymal stem cells (ADSC) represents a novel approach for the management of perianal fistula in patients with Crohn's disease. A randomised study on an animal model was performed to investigate the efficacy and to detect the distribution of implanted ADSCs by bioluminescence (BLI).

MATERIALS AND METHODS

A caecostomy was used as a fistula model in 32 Lewis rats. The ADSCs were isolated from transgenic donor expressing firefly luciferase. Animals were randomly assigned to groups given injections of 4 × 10⁶ cells (n = 16, group A) or placebo (n = 16, group B) in the perifistular tissue. Fistula drainage assessment was used to evaluate the fistula healing. After application of D-luciferin, cell viability and distribution was detected using an IVIS Lumina XR camera on days 0, 2, 7, 14 and 30.

RESULTS

The fistula was identified as healed in 6 (38%) animals in group A vs. 1 case (6.3%) in group B (p = .033). The BLI was strongest immediately after administration of ADSCs 31.2 × 10⁴ (6.09-111 × 10⁴) p/s/cm²/sr. The fastest decrease was observed within the first 2 days when values fell by 50.2%. The BLI 30 days after injection was significantly higher in animals with healed fistulas - 8.23 × 10⁴ (1.18-16.9 × 10⁴) vs. 1.74 × 10⁴ (0.156-6.88 × 10⁴); p = .0393.

CONCLUSIONS

Local application of ADSCs resulted in significantly higher fistula closure rate on an animal model. BLI monitoring was proved to be feasible and showed rapid reduction of the ADSC mass after application. More viable cells were detected in animals with healed fistula at the end of the follow-up.

Allogeneic guinea pig mesenchymal stem cells ameliorate neurological changes in experimental colitis

Background

The use of mesenchymal stem cells (MSCs) to treat inflammatory bowel disease (IBD) is of great interest because of their immunomodulatory properties. Damage to the enteric nervous system (ENS) is implicated in IBD pathophysiology and disease progression. The most commonly used model to study inflammation-induced changes to the ENS is 2,4,6-trinitrobenzene-sulfonate acid (TNBS)-induced colitis in guinea pigs; however, no studies using guinea pig MSCs in colitis have been performed. This study aims to isolate and characterise guinea pig MSCs and then test their therapeutic potential for the treatment of enteric neuropathy associated with intestinal inflammation.

Methods

MSCs from guinea pig bone marrow and adipose tissue were isolated and characterised in vitro. In in vivo experiments, guinea pigs received either TNBS for the induction of colitis or sham treatment by enema. MSCs were administered at a dose of 1 × 10⁶ cells via enema 3 h after the induction of colitis. Colon tissues were collected 24 and 72 h after TNBS administration to assess the level of inflammation and damage to the ENS. The secretion of transforming growth factor-β1 (TGF-β1) was analysed in MSC conditioned medium by flow cytometry.

Results

Cells isolated from both sources were adherent to plastic, multipotent and expressed some human MSC surface markers. In vitro characterisation revealed distinct differences in growth kinetics, clonogenicity and cell morphology between MSC types. In an in vivo model of TNBS-induced colitis, guinea pig bone marrow MSCs were comparatively more efficacious than adipose tissue MSCs in attenuating weight loss, colonic tissue damage and leukocyte infiltration into the mucosa and myenteric plexus. MSCs from both sources were equally neuroprotective in the amelioration of enteric neuronal loss and changes to the neurochemical coding of neuronal subpopulations. MSCs from both sources secreted TGF-β1 which exerted neuroprotective effects in vitro.

Conclusions

This study is the first evaluating the functional capacity of guinea pig bone marrow and adipose tissue-derived MSCs and providing evidence of their neuroprotective value in an animal model of colitis. In vitro characteristics of MSCs cannot be extrapolated to their therapeutic efficacy. TGF-β1 released by both types of MSCs might have contributed to the attenuation of enteric neuropathy associated with colitis.

Targeting the delivery of systemically administered haematopoietic stem/progenitor cells to the inflamed colon using hydrogen peroxide and platelet microparticle pre-treatment strategies

Haematopoietic stem and progenitor cell (HSC) therapy may be promising for the treatment of inflammatory bowel disorders (IBDs). However, clinical success remains poor, partly explained by limited HSC recruitment following systemic delivery. The mechanisms governing HSC adhesion within inflamed colon, and whether this event can be enhanced, are not known. An immortalised HSC-like line (HPC7) was pre-treated with hydrogen peroxide (H2O2), activated platelet releasate enriched supernatant (PES) or platelet microparticles (PMPs). Subsequent adhesion was monitored using adhesion assays or in vivo ischaemia-reperfusion (IR) and colitis injured mouse colon intravitally. Integrin clustering was determined confocally and cell morphology using scanning electron microscopy. Both injuries resulted in increased HPC7 adhesion within colonic mucosal microcirculation. H2O2 and PES significantly enhanced adhesion in vitro and in the colitis, but not IR injured, colon. PMPs had no effect on adhesion. PES and PMPs induced clustering of integrins on the HPC7 surface, but did not alter their expression. Adhesion to the colon is modulated by injury but only in colitis injury can this recruitment be enhanced. The enhanced adhesion induced by PES is likely through integrin distribution changes on the HPC7 surface. Improving local HSC presence in injured colon may result in better therapeutic efficacy for treatment of IBD.

Ex vivo immunosuppressive effects of mesenchymal stem cells on Crohn's disease mucosal T cells are largely dependent on indoleamine 2,3-dioxygenase activity and cell-cell contact

Introduction

Crohn’s disease (CD) is a disabling chronic enteropathy sustained by a harmful T-cell response toward antigens of the gut microbiota in genetically susceptible subjects. Growing evidence highlights the safety and possible efficacy of mesenchymal stem cells (MSCs) as a new therapeutic tool for this condition. Therefore, we aimed to investigate the effects of bone marrow-derived MSCs on pathogenic T cells with a view to clinical application.

Methods

T-cell lines from both inflamed and non-inflamed colonic mucosal specimens of CD patients and from healthy mucosa of control subjects were grown with the antigen muramyl-dipeptide in the absence or presence of donors’ MSCs. The MSC effects were evaluated in terms of T-cell viability, apoptotic rate, proliferative response, immunophenotype, and cytokine profile. The role of the indoleamine 2,3-dioxygenase (IDO) was established by adding a specific inhibitor, the 1-methyl-DL-tryptophan, and by using MSCs transfected with the small interfering RNA (siRNA) targeting IDO. The relevance of cell-cell contact was evaluated by applying transwell membranes.

Results

A significant reduction in both cell viability and proliferative response to muramyl-dipeptide, with simultaneous increase in the apoptotic rate, was found in T cells from both inflamed and non-inflamed CD mucosa when co-cultured with MSCs and was reverted by inhibiting IDO activity and expression. A reduction of the activated CD4⁺CD25⁺ subset and increase of the CD3⁺CD69⁺ population were also observed when T-cell lines from CD mucosa were co-cultured with MSCs. In parallel, an inhibitory effect was evident on the expression of the pro-inflammatory cytokines tumor necrosis factor-α, interferon-γ, interleukin-17A and -21, whereas that of the transforming growth factor-β and interleukin-6 were increased, and production of the tolerogenic molecule soluble HLA-G was high. These latter effects were almost completely eliminated by blocking the IDO, whose activity was upregulated in MSCs co-cultured with CD T cells. The use of a semipermeable membrane partially inhibited the MSC immunosuppressive effects. Finally, hardly any effects of MSCs were observed when T cells obtained from control subjects were used.

Conclusion

MSCs exert potent immunomodulant effects on antigen-specific T cells in CD through a complex paracrine and cell-cell contact-mediated action, which may be exploited for widespread therapeutic use.

Electronic supplementary material

The online version of this article (doi:10.1186/s13287-015-0122-1) contains supplementary material, which is available to authorized users.

Cell-based therapy approaches: the hope for incurable diseases

Cell therapies aim to repair the mechanisms underlying disease initiation and progression, achieved through trophic effect or by cell replacement. Multiple cell types can be utilized in such therapies, including stem, progenitor or primary cells. This review covers the current state of cell therapies designed for the prominent disorders, including cardiovascular, neurological (Parkinson's disease, amyotrophic lateral sclerosis, stroke, spinal cord injury), autoimmune (Type 1 diabetes, multiple sclerosis, Crohn's disease), ophthalmologic, renal, liver and skeletal (osteoarthritis) diseases. Various cell therapies have reached advanced clinical trial phases with potential marketing approvals in the near future, many of which are based on mesenchymal stem cells. Advances in pluripotent stem cell research hold great promise for regenerative medicine. The information presented in this review is based on the analysis of the cell therapy collection detailed in LifeMap Discovery(®) (LifeMap Sciences Inc., USA) the database of embryonic development, stem cell research and regenerative medicine.

Are stem cells a potential therapeutic tool in coeliac disease?

Despite the growing understanding of its pathogenesis, the treatment of coeliac disease is still based on a lifelong gluten-free diet that, although efficacious, is troublesome for affected patients, and a definitive cure is still an unmet need. In this regard, the development of new chemical- and biological-derived agents has often resulted in unsatisfactory effects when tested in vivo, probably because of their ability to target only a single pathway, whilst the immunological cascade responsible for tissue injury is complex and redundant. The advent of cellular therapies, mainly based on the use of stem cells, is an emerging area of interest since it has the advantage of a multi-target strategy. Both haematopoietic and mesenchymal stem cells have been employed in the treatment of refractory patients suffering from autoimmune diseases, with promising results. However, the lack of immunogenicity makes mesenchymal stem cells more suitable than their haematopoietic counterpart, since their transplantation may be performed in the absence of a myeloablative conditioning regimen. In addition, mesenchymal stem cells have been shown to harbour strong modulatory effects on almost all cells involved in immune response, together with a potent regenerative action. It is therefore conceivable that over the next few years their therapeutic use will increase as their biological interactions with injured tissues become clearer.

Human adipose-derived stem cells attenuate inflammatory bowel disease in IL-10 knockout mice

Inflammatory bowel disease (IBD) is a complex immunological disorder characterized by chronic inflammation caused mainly by unknown factors. The interleukin-10 knockout (IL-10 KO) mouse is a well-established murine model of IBD which develops spontaneous intestinal inflammation that resembles Crohn's disease. In the present study, human adipose-derived mesenchymal stem cells (hAMSCs) were administrated to IL-10 KO mice to evaluate the anti-inflammatory effects of hAMSCs that may attenuate the progress of or treat IBD. After IBD was induced by feeding the IL-10 KO mouse a 125-250 ppm piroxicam mixed diet for 1 week, 2×10(6) hAMSCs were injected into the peritoneum and the mice were switched to a normal diet. After 1 week, the mice were sacrificed and tissue samples were harvested. Tissue scores for inflammation and inflammation-related genes expression were determined. The hAMSC-treated group showed significantly reduced inflammatory changes in histological analysis. Reverse transcription-PCR analysis showed that RANTES, Toll-like receptor 9, and IL-4 expression levels were not significantly different between the groups while IL-12, INF-γ, and TNF-α levels were significantly decreased in the hAMSC treated group. hAMSC attenuated IBD in the IL-10 KO mice by suppressing inflammatory cytokine expression, was mediated by the type 1 helper T cell pathway. Even though only a single injection of hAMSCs was delivered, the effect influenced chronic events associated with inflammatory changes and demonstrated that hAMSCs are a powerful candidate for IBD therapy.

Endometrial regenerative cells as a novel cell therapy attenuate experimental colitis in mice

Background

Endometrial regenerative cells (ERCs) are mesenchymal-like stem cells that can be non-invasively obtained from menstrual blood and are easily grown /generated at a large scale without tumorigenesis. We previously reported that ERCs exhibit unique immunoregulatory properties in vitro, however their immunosuppressive potential in protecting the colon from colitis has not been investigated. The present study was undertaken to determine the efficacy of ERCs in mediating immunomodulatory functions against colitis.

Methods

Colitis was induced by 4% dextran-sulfate-sodium (DSS, in drinking water) in BALB/c mice for 7 days. ERCs were cultured from healthy female menstrual blood, and injected (1 million/mouse/day, i.v.) into mice on days 2, 5, and 8 following colitis induction. Colonic and splenic tissues were collected on day 14 post-DSS-induction. Clinical signs, disease activity index (DAI), pathological and immunohistological changes, cytokine profiles and cell populations were evaluated.

Results

DSS-induced mice in untreated group developed severe colitis, characterized by body-weight loss, bloody stool, diarrhea, mucosal ulceration and colon shortening, as well as pathological changes of intra-colon cell infiltrations of neutrophils and Mac-1 positive cells. Notably, ERCs attenuated colitis with significantly reduced DAI, decreased levels of intra-colon IL-2 and TNF-α, but increased expressions of IL-4 and IL-10. Compared with those of untreated colitis mice, splenic dendritic cells isolated from ERC-treated mice exhibited significantly decreased MHC-II expression. ERC-treated mice also demonstrated much less CD3⁺CD25⁺ active T cell and CD3⁺CD8⁺ T cell population and significantly higher level of CD4⁺CD25⁺Foxp3⁺ Treg cells.

Conclusions

This study demonstrated novel anti-inflammatory and immunosuppressive effects of ERCs in attenuating colitis in mice, and suggested that the unique features of ERCs make them a promising therapeutic tool for the treatment of ulcerative colitis.

Surgical treatment of perianal fistulizing Crohn's disease: from lay-open to cell-based therapy--an overview

Background. Perianal Crohn's disease (CD) can be challenging. Despite the high incidence of fistulizing CD, literature lacks clear guidelines. Several medical, surgical, and combined treatment modalities have been proposed, but evidences are scarce. Methods. We searched the literature to assess the facets of perianal CD, with particular focus on complex fistulae. Disease epidemiology, classification, diagnosis, activity scoring systems, and medical-surgical treatments were assessed. Results. Perianal fistulizing CD is common, frequently associated with upper gastrointestinal and colorectal CD. Complex fistulas often require repeated treatments. Continence is a major concern when dealing with repeated procedures. A prudent pathway is to resolve active sepsis and to limit damages, delaying a definitive treatment to the time when acute phase has been controlled. The improved diagnostic techniques allow better preoperative planning and are useful in monitoring the response to treatment. Besides newer devices, cell-based treatments are promising tools which have recently enriched the treatment portfolio. However, the need for proctectomy is still disturbingly high in CD patients with complex perianal fistulae. Conclusions. Perianal CD can impair quality of life and lead to need for proctectomy. A staged approach is reasonable. Treatment success can be improved by multimodal treatment and collaborative management by experienced gastroenterologists and surgeons.

[Successful autologous haematopoietic stem cell transplantation in severe, therapy-resistant childhood Crohn's disease. Report on the first case in Hungary]

The biological therapy of Crohn's disease, such as infliximab is a powerful approach in the therapy of inflammatory bowel diseases. However, in some patients with aggressive disease course, even a combined immunosuppressive therapy will not result in permanent remission. Hematopoietic stem cell transplantation has emerged as a new potential therapeutic tool for inflammatory bowel diseases. The authors report the case of a 15-year-old boy with severe Crohn's disease resistant to combined immunosuppressive therapy. After a 3-years course of unsuccessful conventional therapy including infliximab, autologous hematopoietic stem cell transplantation was performed which resulted in a complete remission. One year after transplantation the patient has relapsed, but he could be treated effectively with conventional therapy regiments. To the best of knowledge of the authors, this is the first report in Hungary presenting hematopoietic stem cell therapy in patient with severe Crohn's disease.

Regenerative medicine: prospects for the treatment of inflammatory bowel disease

This article reviews the current understanding of the processes driving the development and progression of inflammatory bowel disease (IBD), discusses how the dynamic crosstalk between resident microorganisms, host cells and the immune system is required in order to maintain immune homeostasis, and considers innovative strategies that allow the modification or modulation of the intestinal microorganismal community as a potential approach for treating IBD. This article next rationalizes the use of cell-based regenerative medicine as treatment for IBD, discusses the obstacles hindering its success, summarizes some of the results of recent clinical trials employing these therapies, and discusses ongoing work to enhance mesenchymal stem/stromal cells, making them better suited to the task of repairing the damage within the IBD gut.

Stem cells as potential targeted therapy for inflammatory bowel disease

The incidence and prevalence of inflammatory bowel disease is increasing in Western countries. Current therapies, ranging from anti-inflammatory drugs, immunosuppressive regimens to new biological therapies, remain inadequate. Advances in our understanding of the pathophysiological mechanisms underlying the pathogenetic disease process and the recent findings on the regenerative and immunoregulatory potential of stem cells open new opportunities in the therapy of inflammatory bowel disease. Therapeutic modalities, including hematopoietic stem cells, adult mesenchymal stem/stromal cells, and the recently identified amniotic origin stem cells, attracted much attention in the recent years. The current review highlights the recent pivotal findings for stem cell-based approaches to inflammatory bowel disease therapy.

Mesenchymal stem cell therapy for cardiac inflammation: immunomodulatory properties and the influence of toll-like receptors

BACKGROUND

After myocardial infarction (MI), the inflammatory response is indispensable for initiating reparatory processes. However, the intensity and duration of the inflammation cause additional damage to the already injured myocardium. Treatment with mesenchymal stem cells (MSC) upon MI positively affects cardiac function. This happens likely via a paracrine mechanism. As MSC are potent modulators of the immune system, this could influence this postinfarct immune response. Since MSC express toll-like receptors (TLR), danger signal (DAMP) produced after MI could influence their immunomodulatory properties.

SCOPE OF REVIEW

Not much is known about the direct immunomodulatory efficiency of MSC when injected in a strong inflammatory environment. This review focuses first on the interactions between MSC and the immune system. Subsequently, an overview is provided of the effects of DAMP-associated TLR activation on MSC and their immunomodulative properties after myocardial infarction.

MAJOR CONCLUSIONS

MSC can strongly influence most cell types of the immune system. TLR signaling can increase and decrease this immunomodulatory potential, depending on the available ligands. Although reports are inconsistent, TLR3 activation may boost immunomodulation by MSC, while TLR4 activation suppresses it.

GENERAL SIGNIFICANCE

Elucidating the effects of TLR activation on MSC could identify new preconditioning strategies which might improve their immunomodulative properties.

Granulomas of intestinal tuberculosis and Crohn's disease can be differentiated by CD73 cell surface marker expression: a pilot study

BACKGROUND

Intestinal tuberculosis (ITB) and Crohn's disease are similar granulomatous disorders. Granulomas are present in both and difficult to differentiate on histopathology alone. A recent study demonstrated recruitment of mesenchymal cells (MSCs) at the periphery of granulomas in lymph node tuberculosis which suppressed T cell responses. We hypothesized that granulomas of ITB would also recruit MSCs to evade host immune response.

AIM

The purpose of this study was to demonstrate MSC markers in granulomas of ITB and evaluate whether distribution of MSC markers could differentiate between granulomas of Crohn's and ITB.

METHODS

We initially retrospectively enrolled 17 patients with confirmed ITB (8) or Crohn's (9) with granulomas on histopathology. Tissues were evaluated by immunofluorescence for MSC markers CD29, CD90, CD73 and absence of haematopoietic markers CD31, CD34, CD45 and CD14. Double-staining was done to confirm presence of MSCs. Subsequently, 23 postoperative specimens of Crohn's (18) and ITB (5) were analyzed for validation.

RESULTS

Overall, 27 Crohn's and 13 ITB cases were assessed. CD29 and CD90 positive cells were noted around both ITB and Crohn's granulomas. MSC marker CD73 was expressed around the granulomas of ITB alone and was completely absent in the Crohn's. The subsequent assessment of granulomas in postoperative specimens of Crohn's and ITB also showed similar results.

CONCLUSION

Granulomas of ITB and Crohn's disease can be differentiated by CD73 MSC surface marker expression. The differential CD73 expression around ITB granuloma indicates that Mycobacterium tuberculosis evades host immunity by recruiting MSCs with CD73 expression. MSCs with increased CD73 expression could be the future for therapeutic intervention in Crohn's.

Safety and tolerability of human placenta-derived cells (PDA001) in treatment-resistant crohn's disease: a phase 1 study

BACKGROUND

The clinical utility of cellular therapies is being investigated in a broad range of therapeutic areas. This phase 1 study represents the first exploration of PDA001, a preparation of cells cultured from human placental tissue, in subjects with Crohn's disease.

METHODS

Twelve subjects with active, moderate-to-severe Crohn's disease unresponsive to previous therapy were given 2 intravenous infusions of PDA001 1 week apart, monitored weekly for 5 weeks, and assessed at 6 months, 1 year, and 2 years after infusion. Six subjects received 2 infusions of 2 × 10 cells (low dose), and 6 subjects received 2 infusions of 8 × 10 cells (high dose).

RESULTS

Mean baseline Crohn's Disease Activity Index in the low-dose and high-dose groups was 305 and 364, respectively, and mean C-reactive protein was 8 mg/L and 49 mg/L, respectively. All subjects in the low-dose group achieved a clinical response (a Crohn's Disease Activity Index decrease of ≥70 points versus baseline), and 3 achieved remission (a Crohn's Disease Activity Index decrease of ≥100 to <150 points). Two subjects in the high-dose group achieved response, and none met remission criteria. Most adverse events were mild to moderate in severity and included headache, nausea, fever, and infusion site reactions.

CONCLUSIONS

PDA001 infusions appear safe and well-tolerated in subjects with treatment-resistant Crohn's disease. A response was seen in all subjects in the low-dose group. The high-dose group, with a higher baseline disease activity, had only 2 responders, suggesting a more treatment-resistant population. A phase 2 study in this patient population is ongoing.

Autologous adipose tissue-derived stem cells for the treatment of Crohn's fistula: a phase I clinical study

The present study was designed to evaluate the safety and potential of adipose tissue-derived stem cells (ASCs) for the treatment of Crohn's fistula. In this dose escalation study, patients were sequentially enrolled into three dosing groups with at least three patients per group. The first three patients (group 1) were given 1 × 10(7) cells/ml. After 4 weeks, this dose was deemed safe, and so an additional four patients (group 2) were given 2 × 10(7) cells/ml. Four weeks later, after which this second dose was deemed safe, a third and final group of three patients were given 4 × 10(7) cells/ml. Each patient was followed for a minimum of 8 weeks. Patients who showed complete healing at week 8 were followed up for an additional 6 months. Efficacy endpoint was complete healing at week 8 after injection, defined as complete closure of the fistula track and internal and external openings without drainage or signs of inflammation. There were no grade 3 or 4 severity adverse events, and there were no adverse events related to the study drug. Two patients in group 2, treated with 2 × 10(7) ASCs/ml, showed complete healing at week 8 after injection. Of the three patients enrolled in group 3, treated with 4 × 10(7) ASCs/ml, one showed complete healing. Outcome in another patient was assessed as partial healing due to incomplete closure of the external opening, although the inside of fistula track was filled considerably and there was no drainage. All three patients with complete healing at week 8 showed a sustained effect without recurrence 8 months after injection. In conclusion, this study demonstrates the tolerability, safety, and potential efficacy of ASCs for the treatment of Crohn's fistula and provides support for further clinical study.

Cardiac stem cell therapy to modulate inflammation upon myocardial infarction

BACKGROUND

After myocardial infarction (MI) a local inflammatory reaction clears the damaged myocardium from dead cells and matrix debris at the onset of scar formation. The intensity and duration of this inflammatory reaction are intimately linked to post-infarct remodeling and cardiac dysfunction. Strikingly, treatment with standard anti-inflammatory drugs worsens clinical outcome, suggesting a dual role of inflammation in the cardiac response to injury. Cardiac stem cell therapy with different stem or progenitor cells, e.g. mesenchymal stem cells (MSC), was recently found to have beneficial effects, mostly related to paracrine actions. One of the suggested paracrine effects of cell therapy is modulation of the immune system.

SCOPE OF REVIEW

MSC are reported to interact with several cells of the immune system and could therefore be an excellent means to reduce detrimental inflammatory reactions and promote the switch to the healing phase upon cardiac injury. This review focuses on the potential use of MSC therapy for post-MI inflammation. To understand the effects MSC might have on the post-MI heart the cellular and molecular changes in the myocardium after MI need to be understood.

MAJOR CONCLUSIONS

By studying the general pathways involved in immunomodulation, and examining the interactions with cell types important for post-MI inflammation, it becomes clear that MSC treatment might provide a new therapeutic opportunity to improve cardiac outcome after acute injury.

GENERAL SIGNIFICANCE

Using stem cells to target the post-MI inflammation is a novel therapy which could have considerable clinical implications. This article is part of a Special Issue entitled Biochemistry of Stem Cells.

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.

Physiological and pathological role of local and immigrating colonic stem cells

The latest avenue of research is revealing the existence of and role for the colonic stem cells in the physiological renewal of the mucosa and in pathological circumstances where they have both positive and negative effects. In the case of human colon, different levels of stem cell compartments exist. First, the crypt epithelial stem cells, which have a role in the normal crypt epithelial cell dynamics and in colorectal carcinogenesis. Close to the crypts, the second layer of stem cells can be found; the local subepithelial stem cell niche, including the pericryptic subepithelial myofibroblasts that regulate the epithelial cell differentiation and have a crucial role in cancer progression and chronic inflammation-related fibrosis. The third level of stem cell compartment is the immigrating bone-marrow-derived stem cells, which have an important role in wound healing after severe mucosal inflammation, but are also involved in cancer invasion. This paper focuses on stem cell biology in the context of physiological and pathological processes in the human colon.

[Preclinical experience in stem cell therapy for digestive tract diseases]

Adult stem cells are multipotent and self-renewing cells that contain several functions; i) migration and homing potential: stem cells can migrate to injured and inflamed tissues. ii) differentiation potential: stem cells which migrated to injured tissues can be differentiated into multiple cell types for repairing and regenerating the tissues. iii) immunomodulatory properties: stem cells, especially mesenchymal stem cells can suppress immune system such as inflammation. All those characteristics might be useful for the treatment of the digestive tract diseases which are complex and encompass a broad spectrum of different pathogenesis. Preclinical stem cell therapy showed some promising results, especially in liver failure, pancreatitis, sepsis, and inflammatory bowel disease. If we can understand more about the mechanism of stem cell action, stem cell therapy can become a promising alternative treatment for refractory digestive disease in the near future. In this review, we summarized current preclinical experiences in diseases of the digestive tract using stem cells. (Korean J Gastroenterol 2011;58:133-138).