Expression of CD4+ forkhead box P3 (FOXP3)+ regulatory T cells in inflammatory bowel disease

FoxP3-positive T regulatory cells and its effector mechanisms in Crohn's disease: an immunohistochemical and image morphometric analysis on endoscopic mucosal biopsies

OBJECTIVE

Crohn's disease (CD) is an immune inflammatory disorder of the gastrointestinal tract arising from a complex interplay of genetic, environmental, microbiome, and immune factors. Regulatory T cells (Tregs), characterized by FoxP3 expression, are crucial for maintaining immune homeostasis through PD-1/PD-L1 interaction, interleukin (IL)-10 release, and granzyme (GrB) production. This study aimed to elucidate the role of FoxP3 positive (+) Tregs in CD.

METHODS

Segmental colonoscopic biopsies from 46 treatment-naive CD cases (34 adults and 12 children) categorized into noninflamed [n = 32; Nancy histologic index (NHI) 0, 1] and inflamed (n = 100; NHI 2-4) mucosae using NHI. CD4, FoxP3, PD-1, IL-10, and GrB immunoexpression were analyzed by eyeballing and image morphometry. Findings were correlated with activity, granulomas, and skip lesions; and compared with site-matched non-inflammatory bowel disease (IBD) controls (n = 30).

RESULTS

FoxP3+ Tregs, IL-10, PD-1, and GrB expressions were significantly higher in NHI 3-4 mucosae than in NHI 0-1 and controls (P < 0.05). No significant differences were observed between adults and children, whereas those with granulomas had increased expression (P = 0.045). The FoxP3 : CD4 ratio positively correlated with IL-10 (Spearman, r = 0.307, P = 0.002), GrB (r = 0.302, P = 0.002), but not with PD-1 (r = 0.98, P = 0.33).

CONCLUSIONS

Our findings point to the possibility of a qualitative defect in FoxP3+ Tregs in CD. The functional arms of Tregs in CD need to be elucidated further in larger prospective cohorts to validate our observations and pave the way for future immunotherapy.

Protective effects and mechanisms of HuDiChangRong capsule on TNBS-induced ulcerative colitis in mice

ETHNOPHARMACOLOGICAL RELEVANCE

UC, characterized by chronic inflammation primarily affecting the colon and rectum, follows a protracted relapsing course marked by inflammation and an abundance of free radicals at the onset. Hudichangrong Capsule (HDCRC), a traditional Chinese medicinal formula, has long been employed in the treatment of UC and chronic bacillary dysentery, exhibiting positive therapeutic outcomes and a high rate of cure in clinical practice.

AIM OF THE STUDY

The precise mechanism underlying its efficacy for UC remains elusive. Our objective was to investigate the anti-inflammatory effect and underlying mechanisms of HDCRC on TNBS-induced UC.

MATERIALS AND METHODS

Here, we introduced HDCRC and induced UC using TNBS. SPF BALB/c mice were divided into 6 groups as follows: control group, colitis model group, colitis treated with sulfasalazine (400 mg/kg) group, and colitis treated with HDCRC (156, 312, and 624 mg/kg) groups. To assess the effects of HDCRC on colitis, we measured body weight loss, disease activity index (DAI), colon length, tissue damage, degree of inflammation, immune capacity, and oxidative stress. Additionally, we evaluated the TLR-4/MyD88 pathway and its downstream signaling using immunohistochemistry, real-time qPCR, and Western blot. Network pharmacology was used for main target prediction. 16s rRNA was employed for gut microbiota detechtion and UPLC-QTOF-MS was used for its and its metabonomics.

RESULTS

HDCRC significantly slowed weight loss, ameliorated DAI, restored colon length, alleviated TNBS-induced tissue damage. It exerted the therapeutic effects via reducing oxidative stress, restoring immune balance, normalizing the inflammatory mediator levels and restoring intestinal barrier integrity. Furthermore, HDCRC mainly alleviate UC via suppressing the TLR-4/MyD88 pathway and its downstream signaling. The key components of the downstream pathway, including TLR-4, MyD88, NF-κB p65, ERK, p-JNK, p38, p-JAK1, JAK1, p-STAT3, and STAT3, were improved, thereby ameliorating the TNBS-induced injury. In addition, HDCRC could regulate gut microbiota (eg. Erysipelaloclostridium,etc.) and its metabonomics (eg. Vitamin B6 metabolism) in UC mice.

CONCLUSIONS

In conclusion, HDCRC exerts a protective effect against TNBS-induced UC in mice by inhibiting the TLR-4/MyD88 pathway and its downstream signaling, and partially JAK1/STAT3, suppressing oxidative stress, regulating immunity, restoring intestinal barrier integrity, and regulating gut microbiota and its metabonomics.

Microbiome characterization of patients with Crohn disease and the use of fecal microbiota transplantation: A review

Inflammatory bowel disease is a chronic inflammatory condition predominantly affecting the intestines, encompassing both ulcerative colitis and Crohn disease (CD). As one of the most common gastrointestinal disorders, CD's pathogenesis is closely linked with the intestinal microbiota. Recently, fecal microbiota transplantation (FMT) has gained attention as a potential treatment for CD, with the effective reestablishment of intestinal microecology considered a crucial mechanism of FMT therapy. This article synthesizes the findings of population-based cohort studies to enhance our understanding of gut microbial characteristics in patients with CD. It delves into the roles of "beneficial" and "pathogenic" bacteria in CD's development. This article systematically reviews and compares data on clinical response rates, remission rates, adverse events, and shifts in bacterial microbiota. Among these studies, gut microbiome analysis was conducted in only 7, and a single study examined the metabolome. Overall, FMT has demonstrated a partial restoration of typical CD-associated microbiological alterations, leading to increased α-diversity in responders and a moderate shift in patient microbiota toward the donor profile. Several factors, including donor selection, delivery route, microbial state (fresh or frozen), and recipient condition, are identified as pivotal in influencing FMT's effectiveness. Future prospective clinical studies with larger patient cohorts and improved methodologies are imperative. In addition, standardization of FMT procedures, coupled with advanced genomic techniques such as macroproteomics and culture genomics, is necessary. These advancements will further clarify the bacterial microbiota alterations that significantly contribute to FMT's therapeutic effects in CD treatment, as well as elucidate the underlying mechanisms of action.

FOXP3 full length splice variant is associated with kidney allograft tolerance

Background

Progressive decline of allograft function leads to premature graft loss. Forkhead box P3 (FOXP3), a characteristic gene of T-regulatory cells, is known to be essential for auto-antigen tolerance. We assessed the hypothesis that low FOXP3 mRNA splice variant levels in peripheral blood cells early after transplantation are associated with progressive allograft injury.

Methods

Blood samples were prospectively collected from 333 incident kidney transplant recipients on the first and 29th postoperative day. We used quantitative polymerase chain reaction to determine transcripts of 3 isotypes of FOXP3 splice variants, including pre-mature FOXP3 and full length FOXP3 (FOXP3fl). We investigated the association between FOXP3 splice variant levels and the declines in estimated glomerular filtration rate (eGFR) of more than 5ml/min/1.73m2 within the first-year post-transplant using logistic regression.

Results

We observed lower FOXP3fl levels in recipients with declining eGFR (N = 132) than in recipients with stable eGFR (N = 201), (logarithmic value -4.13 [IQR -4.50 to -3.84] vs -4.00 [4.32 to -3.74], p=0.02). In ad hoc analysis pre-transplant FOXP3fl levels were similar in both groups. The association between FOXP3fl and declining eGFR was confirmed by multivariable analysis adjusted for potential confounding factors (Odds Ratio 0.51, 95% confidence interval 0.28 to 0.91: p=0.02). When stratifying FOXP3fl levels into quartiles, recipients with lower day1 FOXP3fl had the highest rate of declining eGFR (p=0.04).

Conclusion

Low FOXP3fl splice variant levels at the first postoperative day in kidney transplant recipients were associated with severe decline of eGFR, a well-known surrogate for hard endpoints.

The interplay between the microbiota, diet and T regulatory cells in the preservation of the gut barrier in inflammatory bowel disease

Inflammatory bowel disease (IBD) is becoming more common in the Western world due to changes in diet-related microbial dysbiosis, genetics and lifestyle. Incidences of gut permeability can predate IBD and continued gut barrier disruptions increase the exposure of bacterial antigens to the immune system thereby perpetuating chronic inflammation. Currently, most of the approved IBD therapies target individual pro-inflammatory cytokines and pathways. However, they fail in approximately 50% of patients due to their inability to overcome the redundant pro inflammatory immune responses. There is increasing interest in the therapeutic potential of T regulatory cells (Tregs) in inflammatory conditions due to their widespread capability to dampen inflammation, promote tolerance of intestinal bacteria, facilitate healing of the mucosal barrier and ability to be engineered for more targeted therapy. Intestinal Treg populations are inherently shaped by dietary molecules and gut microbiota-derived metabolites. Thus, understanding how these molecules influence Treg-mediated preservation of the intestinal barrier will provide insights into immune tolerance-mediated mucosal homeostasis. This review comprehensively explores the interplay between diet, gut microbiota, and immune system in influencing the intestinal barrier function to attenuate the progression of colitis.

The Intertwining Roads between Psychological Distress and Gut Microbiota in Inflammatory Bowel Disease

Inflammatory bowel disease represents one of the most life-altering gastrointestinal pathologies, with its multifactorial nature and unclear physiopathology. The most relevant clinical forms, ulcerative colitis and Crohn's disease, clinically manifest with mild to severe flares and remission periods that alter the patient's social, familial and professional integration. The chronic inflammatory activity of the intestinal wall determines severe modifications of the local environment, such as dysbiosis, enteric endocrine, nervous and immune system disruptions and intestinal wall permeability changes. These features are part of the gastrointestinal ecosystem that modulates the bottom-to-top signaling to the central nervous system, leading to a neurobiologic imbalance and clinical affective and/or behavioral symptoms. The gut-brain link is a bidirectional pathway and psychological distress can also affect the central nervous system, which will alter the top-to-bottom regulation, leading to possible functional digestive symptoms and local inflammatory responses. In the middle of this neuro-gastrointestinal system, the microbiome is a key player, as its activities offer basic functional support for both relays. The present article presents current scientific information that links the pathophysiology and clinical aspects of inflammatory bowel disease and psychiatric symptomatology through the complex mechanism of the gut-brain axis and the modulatory effects of the gut microbiota.

Circulating and intestinal regulatory T cells in inflammatory bowel disease: A systemic review and meta-analysis

Regulatory T cells (Tregs) play an important immunosuppressive role in inflammatory bowel disease (IBD). However, findings on the quantitative and functional changes of intestinal and circulating Tregs in patients with IBD are rather contradictory. We therefore conducted a meta-analysis on this issue. The pooled effect was assessed using the standardized mean difference (SMD) with a 95% confidence interval (CI), and subgroup analyses were performed to investigate heterogeneity. This analysis included 764 IBD (402 UC and 362 CD) patients and 341 healthy controls (HCs) pooled from 17 eligible studies. The percentage of circulating Tregs was significantly decreased in active IBD patients compared to HCs (SMD = -0.95, p < 0.001) and inactive IBD patients (SMD = -0.80, p < 0.001). There was no difference in the percentage of circulating Tregs between inactive IBD patients and HCs. The suppressive function of circulating Tregs was impaired in active IBD patients according to limited data (SMD = -0.75, p = 0.02). Besides, the percentage of intestinal Tregs was significantly higher in inflamed regions than in non-inflamed regions (SMD = 0.85, p < 0.001). Our study quantitatively summarized the quantitative and functional changes of Tregs and supported the therapeutic potential of Tregs in IBD. Moreover, additional research into the functions and characteristics of intestinal Tregs in IBD is needed.

Blood regulatory T cells in inflammatory bowel disease, a systematic review, and meta-analysis

INTRODUCTION

Inflammatory bowel disease (IBD) is an autoimmune disease involving various parts of the gastrointestinal (GI) tract, which includes Crohn's disease (CD) and ulcerative colitis (UC). Due to the contradictory results regarding the percentage of peripheral blood (PB) regulatory T cells (Tregs) in IBD patients, this meta-analysis aimed to determine the Tregs frequency in IBD patients.

METHOD

We searched PubMed, Web of Science, SCOPUS, and Google Scholar databases for relevant observational articles that analyzed and reported the frequency of PB Tregs in IBD patients and healthy control groups. After choosing the related articles by two reviewers, the data regarding the definition of Tregs and their frequencies in different groups were recorded.

RESULT

In 22 studies, the results showed a nonsignificant difference in the frequency of PB Tregs between IBD cases and control subjects (SMD: -0.27, 95 % CI: -0.78, 0.23). However, the frequency of CD4⁺CD25⁺CD127^- (SMD: -0.89, 95 % CI: -1.52, -0.26) and CD4⁺CD25⁺FoxP3⁺ (SMD: -1.32, 95 % CI: -2.37, -0.26) Tregs were significantly lower in IBD cases, compared to healthy subjects. Also, UC cases and active IBD cases showed a significantly lower frequency of Treg cells, compared to controls and remission IBD cases, respectively (SMD: -0.68, 95 % CI: -1.24, -0.11 and SMD: -0.60, 95 % CI: -0.93, -0.27).

CONCLUSION

Our study highlighted a probable decrease of Tregs in IBD patients, especially the patients with active states of the disease. The decrease of Treg cells might cause an imbalance in the immune system and the over-activation of auto-immune responses against the digestive tract.

Mesenchymal Stem Cells for the Treatment of Acetic Acid-Induced Ulcerative Colitis in Rats

Background: Ulcerative colitis (UC) is an autoimmune inflammatory bowel disease, characterized by chronic and relapsing inflammation of the intestinal mucosa. Clinical treatments fail to reduce inflammation and induce side effects in nearly 30% of patients. Mesenchymal stem cells (MSCs) are immunomodulatory agents that can encourage tissue repair and regeneration. Aim: To investigate the ability of MSCs to differentiate into enterocytes under the mediation of activin a, fibroblastic growth factor 2, and epidermal growth factors and to study the effect of administering MSCs to rats with acetic acid (AA)-induced UC. Methods: MSCs isolated from the umbilical cord were induced to differentiate into enterocytes. The induced cells were morphologically evaluated by flow cytometry and immunocytochemistry. Forty rats were divided into four groups: control, AA-induced UC, differentiated, and undifferentiated MSC treated groups. The acute UC in rats was induced by 3% AA transrectal administration. Body weight changes, disease activity index (DAI), and histopathological and immunohistochemical CD105 and CD34 staining were recorded. IL-17, IL-10, and TGF- β levels were measured as well. Results: In Both differentiated and undifferentiated MSCs, induced MSCs improved the DAI score and significantly recovered the pathological changes. The favorable effect of MSCs was significantly linked to CD105 overexpression and CD34 low expression. IL-10 and TGF-β levels increased while IL-17 levels decreased. Conclusion: Both differentiated and undifferentiated MSCs showed anti-inflammatory and immunomodulatory effects in our study. Based on our results, MSCs could become potentially useful for regenerative medicine and the clinical treatment of UC.

The Function of Natural Polysaccharides in the Treatment of Ulcerative Colitis

Ulcerative colitis (UC) is an inflammatory bowel disease that is persistent and nonspecific. There are several medications available for the treatment of UC. However, conventional UC medications have substantial adverse effects, low clinical effectiveness, and a high recurrence rate. Therefore, it is critical to discover new medicines that are both safe and effective for UC patients. Natural polysaccharides offer a wide range of pharmacological benefits, including anti-inflammatory, anti-virus, anti-tumor, anti-aging, immune enhancement, and gut flora regulation. In the therapy of UC, natural polysaccharides can modulate inflammatory factors, the immune system, and intestinal flora, and preserve the intestinal mucosa. It demonstrates a good curative effect and is of safety to use, thereby being a potential treatment for UC patients. This paper covers the structure, the pharmacological effects on UC, and the mechanisms of natural polysaccharides. Finally, limitations, challenges, and perspectives are discussed. It is hoped that the findings of this publication will inspire more natural polysaccharides research and provide a theoretical foundation for the creation of new UC medications.

Anti-inflammatory Effect of a Novel Pectin Polysaccharide From Rubus chingii Hu on Colitis Mice

Rubus chingii Hu has been used as a functional food for a long time. A novel pectin polysaccharide named RCHP-S from R. chingii Hu was structurally identified and explored its anti-inflammatory effect on colitis mice. RCHP-S was composed of mannose, rhamnose, glucuronic acid, galacturonic acid, glucose, galactose, and arabinose. NMR spectroscopy and methylation analysis showed that RCHP-S was mainly composed of HG-type pectin domains but also contains a small amount of RG-I. The anti-inflammatory tests indicated that the mouse macrophage RAW 264.7 cells pretreated with RCHP-S could show a significant inhibitory effect on the mRNA level of iNOS, IL-1β, IL-6, and TNF-α in vitro. Polysaccharide RCHP-S reduced the enteritis symptoms in dextran sulfate sodium (DSS)-induced colitis mice by inhibiting released inflammatory factors. These results indicated that the R. chingii Hu polysaccharide can be used as food additives for the treatment of intestinal inflammation.

Identification of Differentially Expressed Genes in COVID-19 and Integrated Bioinformatics Analysis of Signaling Pathways

Coronavirus disease 2019 (COVID-19) is acutely infectious pneumonia. Currently, the specific causes and treatment targets of COVID-19 are still unclear. Herein, comprehensive bioinformatics methods were employed to analyze the hub genes in COVID-19 and tried to reveal its potential mechanisms. First of all, 34 groups of COVID-19 lung tissues and 17 other diseases' lung tissues were selected from the GSE151764 gene expression profile for research. According to the analysis of the DEGs (differentially expressed genes) in the samples using the limma software package, 84 upregulated DEGs and 46 downregulated DEGs were obtained. Later, by the Database for Annotation, Visualization, and Integrated Discovery (DAVID), they were enriched in the Gene Ontology (GO) terms and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways. It was found that the upregulated DEGs were enriched in the type I interferon signaling pathway, AGE-RAGE signaling pathway in diabetic complications, coronavirus disease, etc. Downregulated DEGs were in cellular response to cytokine stimulus, IL-17 signaling pathway, FoxO signaling pathway, etc. Then, based on GSEA, the enrichment of the gene set in the sample was analyzed in the GO terms, and the gene set was enriched in the positive regulation of myeloid leukocyte cytokine production involved in immune response, programmed necrotic cell death, translesion synthesis, necroptotic process, and condensed nuclear chromosome. Finally, with the help of STRING tools, the PPI (protein-protein interaction) network diagrams of DEGs were constructed. With degree ≥13 as the cutoff degree, 3 upregulated hub genes (ISG15, FN1, and HLA-G) and 4 downregulated hub genes (FOXP3, CXCR4, MMP9, and CD69) were screened out for high degree. All these findings will help us to understand the potential molecular mechanisms of COVID-19, which is also of great significance for its diagnosis and prevention.

Oral delivery of a functional algal-expressed TGF-β mimic halts colitis in a murine DSS model

Inflammatory bowel disease (IBD) is a set of immunological disorders which can generate chronic pain and fatigue associated with the inflammatory symptoms. The treatment of IBD remains a significant hurdle with current therapies being only partially effective or having significant side effects, suggesting that new therapies that elicit different modes of action and delivery strategies are required. TGM1 is a TGF-β mimic that was discovered from the intestinal helminth parasite Heligmosomoides polygyrus and is thought to be produced by the parasite to suppress the intestinal inflammation response to help evade host immunity, making it an ideal candidate to be developed as a novel anti-inflammatory bio-therapeutic. Here we utilized the expression system of the edible green algae Chlamydomonas reinhardtii in order to recombinantly produce active TGM1 in a form that could be ingested. C. reinhardtii robustly expressed TGM1, and the resultant recombinant protein is biologically active as measured by regulatory T cell induction. When delivered orally to mice, the algal expressed TGM1 is able to ameliorate weight loss, lymphadenopathy, and disease symptoms in a mouse model of DSS-induced colitis, demonstrating the potential of this biologic as a novel treatment of IBD.

Translating Treg Therapy for Inflammatory Bowel Disease in Humanized Mice

Crohn's disease and ulcerative colitis, two major forms of inflammatory bowel disease (IBD) in humans, afflicted in genetically predisposed individuals due to dysregulated immune response directed against constituents of gut flora. The defective immune responses mounted against the regulatory mechanisms amplify and maintain the IBD-induced mucosal inflammation. Therefore, restoring the balance between inflammatory and anti-inflammatory immunepathways in the gut may contribute to halting the IBD-associated tissue-damaging immune response. Phenotypic and functional characterization of various immune-suppressive T cells (regulatory T cells; Tregs) over the last decade has been used to optimize the procedures for in vitro expansion of these cells for developing therapeutic interventional strategies. In this paper, we review the mechanisms of action and functional importance of Tregs during the pathogenesis of IBD and modulating the disease induced inflammation as well as role of mouse models including humanized mice repopulated with the human immune system (HIS) to study the IBD. "Humanized" mouse models provide new tools to analyze human Treg ontogeny, immunobiology, and therapy and the role of Tregs in developing interventional strategies against IBD. Overall, humanized mouse models replicate the human conditions and prove a viable tool to study molecular functions of human Tregs to harness their therapeutic potential.

Improving the Efficacy of Regulatory T Cell Therapy

Autoimmunity is caused by an unbalanced immune system, giving rise to a variety of organ-specific to system disorders. Patients with autoimmune diseases are commonly treated with broad-acting immunomodulatory drugs, with the risk of severe side effects. Regulatory T cells (Tregs) have the inherent capacity to induce peripheral tolerance as well as tissue regeneration and are therefore a prime candidate to use as cell therapy in patients with autoimmune disorders. (Pre)clinical studies using Treg therapy have already established safety and feasibility, and some show clinical benefits. However, Tregs are known to be functionally impaired in autoimmune diseases. Therefore, ex vivo manipulation to boost and stably maintain their suppressive function is necessary when considering autologous transplantation. Similar to autoimmunity, severe coronavirus disease 2019 (COVID-19) is characterized by an exaggerated immune reaction and altered Treg responses. In light of this, Treg-based therapies are currently under investigation to treat severe COVID-19. This review provides a detailed overview of the current progress and clinical challenges of Treg therapy for autoimmune and hyperinflammatory diseases, with a focus on recent successes of ex vivo Treg manipulation.

Prospective validation of CD4+CD25+FOXP3+ T-regulatory cells as an immunological marker to differentiate intestinal tuberculosis from Crohn's disease

BACKGROUND/AIMS

Crohn's disease (CD) and intestinal tuberculosis (ITB) remain "difficult-to-differentiate" diseases. We have previously documented peripheral blood frequency of CD4+CD25+FOXP3+ T-regulatory cells (Treg) as a biomarker to differentiate CD and ITB. We tried to validate these results in a larger cohort of CD and ITB patients.

METHODS

Seventy treatment naïve patients of CD (n = 23) and ITB (n = 47) (diagnosed by standard criteria) were recruited prospectively from October 2016 to May 2017. Patients with history of antitubercular therapy in the past were excluded. The frequency of Treg cells in peripheral blood was determined by flow cytometry, and compared between CD and ITB patients.

RESULTS

Similar to our previous study, frequency of Treg cells in peripheral blood was significantly increased in ITB as compared to CD patients (40.9 [interquartile range, 33-50] vs. 24.9 [interquartile range, 14.4-29.6], P< 0.001). Further, the receiver operating characteristics curve also showed good diagnostic accuracy with an area under the curve (AUC) of 0.77 (95% confidence interval, 0.65-0.89) and a FOXP3+ cutoff value of > 31.3% had a sensitivity and specificity of 83% and 82.6% respectively, to differentiate ITB from CD. Even for the indeterminate cases (n = 33), Treg cell frequency had similar diagnostic accuracy with an AUC of 0.85 (95% confidence interval, 0.68-0.95) and a cutoff of 32.37% had sensitivity and specificity of 87% and 95% respectively, to differentiate ITB from CD.

CONCLUSIONS

The current findings validate that the increased frequency of CD4+CD25+FOXP3+ Treg in the peripheral blood can be used as a biomarker with high diagnostic accuracy to differentiate ITB from CD.

The critical role of Faecalibacterium prausnitzii in human health: An overview

Faecalibacterium prausnitzii (F. prausnitzii) is one of the most abundant bacterial species in the colon of healthy human adults and representing more than 5% of the total bacterial population. Recently, it has been known as a major actor in human intestinal health and a biosensor. Changes in this species population richness and quantity have been observed in many illnesses and several investigations have reported that abundance of F. prausnitzii is reduced in different intestinal disorders. In the current review, we aim to consider literature from various library databases and electronic searches (Science Direct, PubMed, and Google Scholar) which were randomly collected and serve as an overview of different features of F. prausnitzii including metabolites, anti-inflammatory action, and correlation of dysbiosis of this bacterium with various complications in human.

Enhancement of Circulating and Intestinal T Regulatory Cells and Their Expression of Helios and Neuropilin-1 in Children with Inflammatory Bowel Disease

Background/Aims

The proportions of intestinal and peripheral regulatory T cells (Tregs) in pediatric inflammatory bowel disease (IBD) were poorly investigated, as well as different subsets of these cells. Helios and Neuropilin-1 were proposed as markers differentiating between thymic and peripheral Tregs. Therefore, the aim of current work was to investigate the proportions of Tregs and expression of Helios and Neuropilin-1 in Tregs in peripheral blood and intestinal mucosa of children with inflammatory bowel disease.

Materials and methods

Fifteen patients newly diagnosed with inflammatory bowel disease: ulcerative colitis (n=7) and Crohn's disease (n=8) were included in the study. Nine children who presented with no abnormalities in colonoscopy served as a control group. Quantification of regulatory T cells of the CD4⁺CD25^highFOXP3⁺ phenotype, as well as Helios⁺ and Neuropilin-1⁺ in peripheral blood and bowel mucosa was based on multicolor flow cytometry.

Results

The rates of circulating and intestinal Tregs were significantly higher in the studied group than in the control group. The rate of intestinal T regulatory lymphocytes was significantly higher than circulating Tregs in patients with IBD, but not in the control group. The median proportion of circulating FOXP3⁺Helios⁺ cells amounted to 24.83% in IBD patients and 15.93% in the controls. The median proportion of circulating FOXP3⁺Nrp-1⁺ cells was 34.23% in IBD and 21.01% in the control group. No statistically significant differences were noted for the circulating FOXP3⁺Helios⁺ cells and FOXP3⁺Nrp-1⁺ cells between the studied and the control group.

Conclusion

The rates of circulating and intestinal T regulatory cells are increased in naïve pediatric patients with IBD. The rate of Tregs is higher in intestinal mucosa than in peripheral blood in patients with IBD. Flow cytometry is a valuable method assessing the composition of infiltrates in inflamed tissue. Helios and Neuropilin-1 likely cannot serve as markers to differentiate between natural and adaptive Tregs.

Polysaccharides from natural resources exhibit great potential in the treatment of ulcerative colitis: A review

The incidence of ulcerative colitis (UC) is high. Despite the availability of various therapeutic agents for the treatment of UC, the routine treatment has limitations and serious side effects. Therefore, a new drug that safely and effectively treats UC is urgently needed. Polysaccharides from natural resources have recently become a hot topic of study for their therapeutic effects on UC. These effects are associated with the regulation of inflammatory cytokines, intestinal flora, and immune system and protection of the intestinal mucosa. This review focuses on the recent advances of polysaccharides from natural resources in the treatment of UC. The mechanisms and practicability of polysaccharides, including pectin, guar gum, rhamnogalacturonan, chitosan, fructan, psyllium, glycosaminoglycan, algal polysaccharides, polysaccharides from fungi and traditional Chinese medicine, and polysaccharide derivatives, are discussed in detail. The good efficacy and safety of polysaccharides make them promising drugs for treating UC.

Immunological outcomes in infants with ROP after dexamethasone and aminophylline

This research aims to improve anaesthesia services given to preterm infants by the use of dexamethasone and aminophylline administrated under sevoflurane, and to analyze its effect on the cell-mediated immunity (CD4+CD25+Foxp3+(T-reg) and CD4+CD25highFoxp3+CD127low). We have examined 74 premature babies with retinopathy of prematurity (ROP) at the 3-5 stages during the 25-32 week gestation period (1-6 months after birth). Both immunomodulators had no significant effect on clinical parameters after one dose (P > .05). Aminophylline (2.4% solution, 0.1 mL/kg or 0.132 mL per infant on average) and dexamethasone (0.4% solution, 0.1 mg/kg or 0.132 mL per infant on average) were intravenously injected 15 minutes before the end of the surgery. Required anaesthesia depth was maintained with inhalation anaesthetic (1.5-2.0 IAC), and the minimum fresh gas flow was not less than 2 L. Blood samples were taken from the vein (anaesthesia induction stage) into the tubes containing EDTA (the anticoagulant), stored at 20-25°C, and then, processed and stained within 24 hours after sampling. Both immunomodulators had no significant effect on clinical parameters after one dose (P > .05). Short-term shift in regulatory T-cell level affected by dexamethasone has a negative effect combined with further withdrawal effect that this hormonal drug has. Aminophylline has such clinical effects as improving pulmonary ventilation, decrease in apnoea frequency, and improving blood gas indices. Aminophylline has less expressed but more prolonged positive effect during the day when used for several days. It may lead to a persistent positive effect with progressive treatment outcomes.

Tryptophan Metabolism, Regulatory T Cells, and Inflammatory Bowel Disease: A Mini Review

Inflammatory bowel disease (IBD) is a chronic inflammatory disorder of the gastrointestinal tract resulting from the homeostasis imbalance of intestinal microenvironment, immune dysfunction, environmental and genetic factors, and so on. This disease is associated with multiple immune cells including regulatory T cells (Tregs). Tregs are a subset of T cells regulating the function of various immune cells to induce immune tolerance and maintain intestinal immune homeostasis. Tregs are correlated with the initiation and progression of IBD; therefore, strategies that affect the differentiation and function of Tregs may be promising for the prevention of IBD-associated pathology. It is worth noting that tryptophan (Trp) metabolism is effective in inducing the differentiation of Tregs through microbiota-mediated degradation and kynurenine pathway (KP), which is important for maintaining the function of Tregs. Interestingly, patients with IBD show Trp metabolism disorder in the pathological process, including changes in the concentrations of Trp and its metabolites and alteration in the activities of related catalytic enzymes. Thus, manipulation of Treg differentiation through Trp metabolism may provide a potential target for prevention of IBD. The purpose of this review is to highlight the relationship between Trp metabolism and Treg differentiation and the role of this interaction in the pathogenesis of IBD.

Regulatory T cells in Crohn's disease following anti-TNF-α therapy

BACKGROUND AND AIM

Anti-tumor necrosis factor alpha (TNF-α) therapy is an effective therapy for Crohn's disease (CD). We investigated FoxP3+ and CD127- regulatory T cells (Tregs) before and after administration of anti-TNF-α therapy in CD.

METHODS

Eight patients with active CD who had received anti-TNF-α antibodies were enrolled. Treatment responses were followed by physical examination and Crohn's disease activity index (CDAI) scoring before and 2 weeks after the initial administration of anti-TNF-α antibodies. Peripheral blood samples were collected before and 2 weeks after treatment. White blood cell count and serum levels of C-reactive protein (CRP) and albumin were measured. FoxP3+ expression and CD127- Tregs were measured by fluorescence activated cell sorting (FACS) analysis of whole blood samples.

RESULTS

Median values of CDAI decreased significantly after treatment. The proportion of FoxP3+ Tregs increased significantly after treatment. There was a significant negative correlation between ΔCD127- Tregs and Δlymphocyte.

CONCLUSIONS

Anti-TNF-α therapy would enhance Tregs, which may account for the mechanism underlying the positive effect of the anti-TNF-α treatment in CD patients.

Increased frequency of regulatory T cells in pediatric inflammatory bowel disease at diagnosis: a compensative role?

BACKGROUND

Regulatory T cells (Tregs) play a critical role in maintaining immune homeostasis. We investigated two main types of Tregs, the CD4+FOXP3+ and IL-10+ Tr1, in pediatric subjects with inflammatory bowel disease (IBD) both at diagnosis and after the clinical remission.

METHODS

Peripheral blood Tregs were analyzed in 16 children with Crohn's disease (CD), 19 with ulcerative colitis (UC), and 14 healthy controls (HC). Two cocktails of fluoresceinated antibodies were used to discriminate between CD4+FOXP3+ and Tr1.

RESULTS

We observed in both CD and UC groups a higher frequency of Tr1 at diagnosis compared to controls, which decreased at follow-up compared to diagnosis, in particular in UC. Similarly, in UC patients the percentage of CD4+FOXP3+ Tregs markedly decreased at follow-up compared to the same patients at diagnosis and compared to HC. The expression of CTLA-4 in CD4+FOXP3+ Tregs increased in both groups at clinical remission.

CONCLUSION

This study shows that IBD children present at diagnosis an increased frequency of circulating Tregs, probably as a compensative reaction to tissue inflammation. During the clinical remission, the Treg frequency diminishes, and concomitantly, their activation status increases. Notwithstanding, the high Treg density at diagnosis is not sufficient to counteract the inflammation in the childhood IBD.

IBD: Role of intestinal compartments in the mucosal immune response

BACKGROUND AND AIMS

Laser capture microdissection (LCM) is a powerful tool for the isolation of specific tissue compartments. We aimed to investigate the mucosal immune response that takes place in different intestinal compartments of IBD patients, dissected by LCM, analyzing cytokines expression profile and endoplasmic reticulum (ER) stress markers.

METHODS

Frozen sections of gut were obtained from patients with Crohn's disease (CD), ulcerative colitis (UC) and from controls. Using LCM, surface epithelium (SE) and lamina propria (LP) compartments were isolated and total RNA extracted. The relative expression of Th1, Th17 and Treg cytokines was evaluated by quantitative reverse transcriptase real-time PCR (qRT-PCR), in addition to the assessment of mRNA splicing of the transcription factor X-box binding protein-1 (XBP1). Human neutrophil elastase (HNE) and the transcription factor forkhead box P3 (Foxp3) were also analyzed by immunohistochemistry.

RESULTS

The increased expression of IL-17 was observed in both intestinal compartments of IBD patients when compared to controls. IFN- γ, TNF-α , IL-10, HNE and Foxp3 were overexpressed in the LP compartment of both IBD patients as compared to controls. An upregulation of IFN-γ and an infiltration of HNE+ cells was found in the SE of patients with UC. Splicing of XBP1 mRNA was recognized in both intestinal compartments of IBD patients when compared to controls.

CONCLUSIONS

In IBD patients, both intestinal compartments are involved in Th17 response, whereas, LP compartment plays a prominent role in Th1 and Treg immune responses. Nevertheless, high level of IFN- γ was found in the SE of UC patients, suggesting that this compartment is involved in the Th1 immune response. Our data also suggested that ER stress signalling is active in both LP and SE compartment of IBD patients, thus advocating that ER stress and immunity are intertwined.

Distribution of regulatory T cells in inflammatory colorectal polyps of miniature dachshunds

Inflammatory colorectal polyp (ICRP) is an emerging disease in Miniature Dachshunds (MDs). Animals with this disease exhibit multiple polyps with severe neutrophil infiltration that respond to immunosuppressive therapy. Macrophages in polypoid lesions have been described to play an important role in neutrophil infiltration in the lesion by producing IL-8. In contrast, IL-10, an anti-inflammatory cytokine, was also reported to be upregulated in polypoid lesions, but its significance in the pathogenesis of ICRP has not been clarified. Regulatory T cells (Tregs) are the main source of IL-10 production and contribute to the maintenance of intestinal homeostasis. Therefore, the objective of this research was to compare the distribution of Tregs in polypoid lesions of ICRPs and the association between the distribution and expression of pro- or anti-inflammatory cytokines. Tissue biopsy specimens of polypoid lesions were collected from 28 MDs with ICRP. Those of macroscopically non-polypoid colonic mucosa from 24 MDs with ICRPs and 21 control dogs were further included as controls. Real-time quantitative polymerase chain reaction was used to quantify gene expression of IL-1β, IL-4, IL-6, IL-8, IL-10, IL-17, IL-22, IFN-γ, TNF-α, TGF-β, and forkhead box protein P3 (Foxp3) in each tissue sample. The numbers of Foxp3-positive cells (Tregs) and ionized calcium binding adapter molecule 1 (Iba-1)-positive cells (macrophages) were determined by immunohistochemistry. The gene expression of IL-1β, IL-6, IL-8, TNF-α, IFN-γ, IL-17, IL-10, TGF-β, and Foxp3 was significantly upregulated in polypoid lesions relative to control levels. The numbers of Foxp3-positive Tregs and Iba-1-positive macrophages were significantly increased in polypoid lesions compared to those in the non-polypoid colonic mucosa of MDs with ICRPs and control dogs. The upregulation of IL-10 was moderately correlated with the distribution of Tregs in polypoid lesions from MDs with ICRPs. In addition, the relative upregulation of IL-1β, IL-6, and IL-8 in polypoid lesions, compared to expression in non-polypoid colonic mucosa of MDs with ICRPs, was significantly greater than that of IL-10. These results indicate that increases in Treg numbers and anti-inflammatory cytokines in polypoid lesions comprise reactive changes in response to the inflammation, which warrants further investigation.

pVAX1-A20 alleviates colitis in mice by promoting regulatory T cells

AIM

To investigate whether the intrarectal administration of the ubiquitin E3 ligase A20 (A20) attenuates intestinal inflammation and influences regulatory T cells in experimental colitis.

METHODS

A dextran sulfate sodium induced chronic colitis mouse model was established. The symptoms and manifestations of colitis and the severity of colonic mucosal inflammation were evaluated. The protective role of A20 expression in the intestine was analyzed after the administration of a pVAX1-A20 recombinant eukaryotic vector, which was encapsulated into poly(L-lactide-co-glycolide) as a nanoparticle.

RESULTS

pVAX1-A20 administration markedly ameliorated colonic tissue damage and reduced intestinal inflammation via the suppression of the mucosal mitogen-activated protein kinase and nuclear factor (NF)-κB signaling cascade. Furthermore, pVAX1-A20 promoted the splenic regulatory T cell population and forkhead box P3 expression in colonic tissue.

CONCLUSION

A20 plays a key role in the regulation of intestinal inflammation and that the overexpression of A20 in the intestine protects mice from dextran sulfate sodium induced chronic colitis.

IL-17A, MCP-1, CCR-2, and ABCA1 polymorphisms in children with non-alcoholic fatty liver disease

OBJECTIVE

The prevalence of non-alcoholic fatty liver disease in children has risen significantly, owing to the worldwide childhood obesity epidemic in the last two decades. Non-alcoholic fatty liver disease is closely linked to sedentary lifestyle, increased body mass index, and visceral adiposity. In addition, individual genetic variations also have a role in the development and progression of non-alcoholic fatty liver disease. The aim of this study was to investigate the gene polymorphisms of MCP-1 (-2518 A/G) (rs1024611), CCR-2 (190 G/A) (rs1799864), ABCA1 (883 G/A) (rs4149313), and IL-17A (-197 G/A) (rs2275913) in obese Turkish children with non-alcoholic fatty liver disease.

METHODS

The study recruited 186 obese children aged 10-17 years, including 101 children with non-alcoholic fatty liver disease and 85 children without non-alcoholic fatty liver disease. Anthropometric measurements, insulin resistance, a liver panel, a lipid profile, liver ultrasound examination, and genotyping of the four variants were performed.

RESULTS

No difference was found between the groups in respect to age and gender, body mass index, waist/hip ratio, or body fat ratio. In addition to the elevated ALT levels, AST and GGT levels were found significantly higher in the non-alcoholic fatty liver disease group compared to the non non-alcoholic fatty liver disease group (p<0.05). The A-allele of IL-17A (-197 G/A) (rs2275913) was associated with non-alcoholic fatty liver disease (odds ratio [OR] 2.05, 95% confidence interval: 1.12-3.77, p=0.02).

CONCLUSIONS

The findings of this study suggest that there may be an association between IL-17A (-197 G/A) (rs2275913) polymorphism and non-alcoholic fatty liver disease development in obese Turkish children.

Association of Crohn's disease with Foxp3 gene polymorphisms and its colonic expression in Chinese patients

BACKGROUND

Fork head/winged helix transcription factor (Foxp3) plays a pivotal role in regulatory T (Treg) cells. The present study aimed to assess the association of Crohn's disease (CD) with Foxp3 polymorphisms and its colonic expression in Chinese patients.

METHODS

The Foxp3 polymorphisms, rs3761547, rs2232365, rs2294021, and rs3761548, were examined by SNaPshot in 268 CD patients and 490 controls. The colonic expression levels of Foxp3, IL-2, and IL-4 were detected in 31 CD patients and 31 controls using real-time quantitative polymerase chain reaction, immunohistochemistry, and enzyme-linked immunosorbent assay.

RESULTS

Compared to male controls, the proportion of variant allele of rs3761547 was increased in male patients. The variant alleles of rs3761547, rs2232365, and rs2294021 were less in male patients with stricturing CD compared to those with non-stricturing, non-penetrating CD; however, these variants were frequently detected in male patients with colonic CD than in those with ileocolonic CD. The variant allele of rs3761548 was increased in male patients with penetrating CD compared to those with non-stricturing, non-penetrating CD. The colonic expression of Foxp3 was higher in CD patients than in controls (both males and females). Compared to male patients carrying wild-type alleles, the colonic expression of Foxp3 was downregulated in male patients with variant alleles, rs3761547, rs2232365, rs2294021, and rs3761548, respectively. However, the Foxp3 polymorphisms were not significantly related with the colonic expression levels of IL-2 and IL-4 in CD patients (both males and females).

CONCLUSION

Foxp3 polymorphisms might increase the CD susceptibility by reducing the colonic expression of Foxp3 in male patients.

Insights into Roseburia intestinalis which alleviates experimental colitis pathology by inducing anti-inflammatory responses

BACKGROUND AND AIM

The study aims to elucidate the anti-inflammatory effect and mechanism of Roseburia intestinalis (R. intestinalis) in Crohn's disease (CD).

METHODS

16S-rRNA genome sequencing technique is used to detect the characteristics of intestinal microbiota in untreated CD patients and healthy controls. Then the study investigates the effects of R. intestinalis on disease activity index score, intestinal pathology, the differentiation of Treg cells, and the expressions of Thymic stromal lymphopoietin (TSLP), TGF-β and IL-10 by using TNBS colitis models. At the cellular level, the study uses LPS to stimulate Caco-2 cells to conduct inflammation models and then co-culture with R. intestinalis and detect changes of TSLP and TGF-β. The study then uses R. intestinalis to stimulate peripheral blood mononuclear cells, and the change of Treg cells was detected.

RESULTS

Genome sequencing of fecal samples from untreated CD patients (n = 10) revealed decreases in the abundance and diversity of intestinal microbiota, including R. intestinalis. Moreover, R. intestinalis reduced disease activity index scores, colon shortening, intestinal mucosal epithelial injury, and mucosal lymphocyte infiltration in a colitis mice model. It suppressed intestinal inflammation by increasing Treg cell numbers and expression of the anti-inflammatory cytokines TSLP, TGF-β, and interleukin-10 (P < 0.05). R. intestinalis also increased secretion of TSLP and TGF-β in lipopolysaccharide-treated Caco-2 cells.

CONCLUSION

These findings suggest that R. intestinalis suppresses CD pathogenesis by inducing anti-inflammatory responses.

CD4+ CD25+ FOXP3+ T cell frequency in the peripheral blood is a biomarker that distinguishes intestinal tuberculosis from Crohn's disease

BACKGROUND

Distinguishing between Crohn's Disease (CD) and Intestinal Tuberculosis (ITB) has been a challenging task for clinicians due to their similar presentation. CD4+FOXP3+ T regulatory cells (Tregs) have been reported to be increased in patients with pulmonary tuberculosis. However, there is no such data available in ITB. The aim of this study was to investigate the differential expression of FOXP3+ T cells in patients with ITB and CD and its utility as a biomarker.

METHODS

The study prospectively recruited 124 patients with CD, ITB and controls: ulcerative colitis (UC) and patients with only haemorrhoidal bleed. Frequency of CD4+CD25+FOXP3+ Tregs in peripheral blood (flow cytometry), FOXP3 mRNA expression in blood and colonic mucosa (qPCR) and FOXP3+ T cells in colonic mucosa (immunohistochemistry) were compared between controls, CD and ITB patients.

RESULTS

Frequency of CD4+CD25+FOXP3+ Treg cells in peripheral blood was significantly increased in ITB as compared to CD. Similarly, significant increase in FOXP3+ T cells and FOXP3 mRNA expression was observed in colonic mucosa of ITB as compared to CD. ROC curve showed that a value of >32.5% for FOXP3+ cells in peripheral blood could differentiate between CD and ITB with a sensitivity of 75% and a specificity of 90.6%.

CONCLUSION

Phenotypic enumeration of peripheral CD4+CD25+FOXP3+ Treg cells can be used as a non-invasive biomarker in clinics with a high diagnostic accuracy to differentiate between ITB and CD in regions where TB is endemic.

Exploring the role of the microbiota member Bifidobacterium in modulating immune-linked diseases

The gut-associated microbiota is essential for multiple physiological processes, including immune development. Acquisition of our initial pioneer microbial communities, including the dominant early life genus Bifidobacterium, occurs at a critical period of immune maturation and programming. Bifidobacteria are resident microbiota members throughout our lifetime and have been shown to modulate specific immune cells and pathways. Notably, reductions in this genus have been associated with several diseases, including inflammatory bowel disease. In this review, we provide an overview of bifidobacteria profiles throughout life and how different strains of bifidobacteria have been implicated in immune modulation in disease states. The focus will be examining preclinical models and outcomes from clinical trials on immune-linked chronic conditions. Finally, we highlight some of the important unresolved questions in relation to Bifidobacterium-mediated immune modulation and implications for future directions, trials, and development of new therapies.

The signaling axis of microRNA-31/interleukin-25 regulates Th1/Th17-mediated inflammation response in colitis

Interleukin-25 (IL-25) is an important regulatory cytokine that has a key role on mucosal immune tolerance during inflammation response. However, the molecular mechanism that regulates the colonic IL-25 expression in Crohn's disease (CD) remains unclear. In this study, IL-25 level was proved to decrease in 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced colitis mice and IL-10 knockout (KO) spontaneous colitis mice. An inverse correlation between IL-25 and miR-31 was discovered in the colons from model mice and CD patients. Furthermore, target validation analysis demonstrated that miR-31 directly regulated IL-25 expression by binding to its messenger RNA 3'-untranslated region. Changing colonic miR-31 level in the colitis mice could affect the mucosal IL-12/23-mediated Th1/Th17 pathway and lead to either amelioration or aggravation of colonic inflammation. In addition, the therapeutic effects of anti-miR-31 in TNBS-induced colitis were abolished by colonic treatment with IL-25 antibody or colonic down-expression of IL-25. Our findings demonstrated that IL-25 could be a crucial anti-inflammatory cytokine in TNBS-induced colitis and the signaling of miR-31 targeting IL-25 might be a possible mechanism that regulates IL-12/23-mediated Th1/Th17 inflammatory responses during colonic inflammation process. Restoring colonic IL-25 expression and blocking Th1/Th17 responses via intracolonic administration of miR-31 inhibitor may represent a promising approach for CD treatment.

Chromatin Remodeling Protein SMAR1 Is a Critical Regulator of T Helper Cell Differentiation and Inflammatory Diseases

T cell differentiation from naïve T cells to specialized effector subsets of mature cells is determined by the iterative action of transcription factors. At each stage of specific T cell lineage differentiation, transcription factor interacts not only with nuclear proteins such as histone and histone modifiers but also with other factors that are bound to the chromatin and play a critical role in gene expression. In this review, we focus on one of such nuclear protein known as tumor suppressor and scaffold matrix attachment region-binding protein 1 (SMAR1) in CD4⁺ T cell differentiation. SMAR1 facilitates Th1 differentiation by negatively regulating T-bet expression via recruiting HDAC1–SMRT complex to its gene promoter. In contrast, regulatory T (T_reg) cell functions are dependent on inhibition of Th17-specific genes mainly IL-17 and STAT3 by SMAR1. Here, we discussed a critical role of chromatin remodeling protein SMAR1 in maintaining a fine-tuned balance between effector CD4⁺ T cells and T_reg cells by influencing the transcription factors during allergic and autoimmune inflammatory diseases.

A lactic acid bacterium isolated from kimchi ameliorates intestinal inflammation in DSS-induced colitis

Some species of lactic acid bacteria have been shown to be beneficial in inflammatory bowel disease (IBD). In the present study, a strain of lactic acid bacterium (Lactobacillus paracasei LS2) was isolated from the Korean food, kimchi, and was shown to inhibit the development of experimental colitis induced by dextran sulfate sodium (DSS). To investigate the role of LS2 in IBD, mice were fed DSS in drinking water for seven days along with LS2 bacteria which were administered intragastrically to some of the mice, while phosphate-buffered saline (PBS) was administered to others (the controls). The administration of LS2 reduced body weight loss and increased survival, and disease activity indexes (DAI) and histological scores indicated that the severity of colitis was significantly reduced. The production of inflammatory cytokines and myeloperoxidase (MPO) activity also decreased. Flow cytometry analysis showed that the number of Th1 (IFN-γ) population cells was significantly reduced in the LS2-administered mice compared with the controls. The administration of LS2 induced the increase of CD4⁺FOXP3⁺ Treg cells, which are responsible for IL-10. Numbers of macrophages (CD11b⁺ F4/80⁺), and neutrophils (CD11b⁺ Gr-1⁺) among lamina propria lymphocytes (LPL) were also reduced. These results indicate that LS2 has an anti-inflammatory effect and ameliorates DSS-induced colitis.

Peripheral and Intestinal T-regulatory Cells are Upregulated in Children with Inflammatory Bowel Disease at Onset of Disease

BACKGROUND/AIMS

To determine the proportion of T-regulatory cells (CD4⁺CD25^highFOXP3⁺ cells) in peripheral blood and the number of FOXP3⁺ cells in intestinal mucosa of children with inflammatory bowel disease (IBD), and to verify whether these parameters correlate with the activity of the disease.

MATERIAL AND METHODS

24 patients newly diagnosed for IBD were included in the study: ulcerative colitis (UC; n = 13) and Crohn's disease (CD; n = 11). Seventeen healthy controls (HC) and 16 patients with irritable bowel syndrome (IBS) served as a control group for peripheral and intestinal Tregs assessment, respectively. The disease activity was assessed by Pediatric Ulcerative Colitis Activity Index (PUCAI) and Pediatric Crohn's Disease Activity Index (PCDAI). Quantification of regulatory T cells of CD4⁺CD25^highFOXP3⁺ phenotype in peripheral blood was based on three-color flow cytometry. Mucosal Tregs represented by FOXP3⁺ cells were evaluated using immunohistochemistry.

RESULTS

Median proportion of CD4⁺CD25^highFOXP3⁺ cells among CD4⁺ T cells in peripheral blood (5.1%, range 1.7-84% vs. 4.3%, range 2-8.1%, p = 0.023) and median number of intestinal FOXP3+ cells (115.33 per high-power field, hpf, range 39.33-375.67 vs. 10.16 per hpf, range 5-30, p = 0.0001) were significantly higher in children with IBD than in the controls. The proportion of circulating Tregs and the number of intestinal FOXP3+ cells did not correlate with clinical activity of the disease, as well as with endoscopic and histopathologic scoring. No significant correlation was found between the percentage of peripheral CD4+CD25^highFOXP3+ cells and the number of intestinal FOXP3+cells.

CONCLUSIONS

Children with IBD likely do not present with a quantitative deficiency of circulating and intestinal Tregs at the moment of diagnosis.

Differential effects of α4β7 and GPR15 on homing of effector and regulatory T cells from patients with UC to the inflamed gut in vivo

OBJECTIVE

Gut homing of lymphocytes via adhesion molecules has recently emerged as new target for therapy in IBDs. We aimed to analyse the in vivo homing of effector (Teff) and regulatory (Treg) T cells to the inflamed gut via α4β7 and G protein receptor GPR15.

DESIGN

We assessed the expression of homing receptors on T cells in peripheral blood and inflamed mucosa. We studied the migration pattern and homing of Teff and Treg cells to the inflamed gut using intravital confocal microscopy and FACS in a humanised mouse model in dextran sodium sulfate-treated NSG (NOD.Cg-Prkdcscid-Il2rgtm1Wjl/SzJ) mice.

RESULTS

Expression of GPR15 and α4β7 was significantly increased on Treg rather than Teff cells in peripheral blood of patients with UC as compared with Crohn's disease and controls. In vivo analysis in a humanised mouse model showed augmented gut homing of UC Treg cells as compared with controls. Moreover, suppression of UC (but not control) Teff and Treg cell homing was noted upon treatment with the α4β7 antibody vedolizumab. In contrast, siRNA blockade of GPR15 had only effects on homing of Teff cells but did not affect Treg homing in UC. Clinical vedolizumab treatment was associated with marked expansion of UC Treg cells in peripheral blood.

CONCLUSIONS

α4β7 rather than GPR15 is crucial for increased colonic homing of UC Treg cells in vivo, while both receptors control UC Teff cell homing. Vedolizumab treatment impairs homing of UC Treg cells leading to their accumulation in peripheral blood with subsequent suppression of systemic Teff cell expansion.

Regional Specialisation of T Cell Subsets and Apoptosis in the Human Gut Mucosa: Differences Between Ileum and Colon in Healthy Intestine and Inflammatory Bowel Diseases

BACKGROUND AND AIMS

There is very limited information regarding region-specific immunological response in human intestine. We aimed to determine differences in immune compartmentalisation between ileum and colon in healthy and inflamed mucosa.

METHODS

T cell profile and its apoptosis were measured by flow cytometry, Th1, Th17, Treg [CD4(+)CD25(+)FOXP3(+)], double positive [DP, CD3(+)CD4(+)CD8(+)] and double negative T cells [DN, CD3(+)CD4(-)CD8(-)], immunohistochemistry [FOXP3, caspase-3], and real-time polymerase chain reaction [PCR] [IFN-γ, IL-17-A, and FOXP3] on biopsies from different regions of healthy intestine and of intestine in inflammatory bowel diseases.

RESULTS

Healthy colon showed higher percentages of Treg, Th17, and DN, and lower numbers of DP T cells compared with ileum [p < 0.05]. Some but not all region-specific differences were lost in inflammatory conditions. Disease-specific patterns were found: a Th1/Th17 pattern and a Th17 pattern in Crohn's disease and ulcerative colitis respectively, whereas a reduction in Th1/Th17 was found in microscopic colitis. In colonic Crohn's disease and microscopic colitis, DN T cells had a pattern inverse to that of Th1/Th17 (increase in microscopic colitis [p < 0.05] and decrease in Crohn's disease [p < 0.005]). Higher levels of lymphocyte apoptosis were found in healthy colon compared with the ileal counterparts [p = 0.001]. All forms of colonic inflammation presented a dramatic decrease in apoptosis compared with healthy colon. By contrast ileal Crohn's disease showed higher levels of cleaved-Caspase(+) CD3(+) cells.

CONCLUSIONS

Immunological differences exist in healthy gastrointestinal tract. Inflammatory processes overwhelm some location-specific differences, whereas others are maintained. Care has to be taken when analysing immune response in intestinal inflammation, as location-specific differences may be relevant.

Increased Intestinal Microbial Diversity Following Fecal Microbiota Transplant for Active Crohn's Disease

BACKGROUND

The microbiota in the lumen of patients with Crohn's disease (CD) is characterized by reduced diversity, particularly Firmicutes and Bacteroidetes. It is unknown whether the introduction of the intestinal microbiota from healthy individuals could correct this dysbiosis and reverse mucosal inflammation. We investigated the response to fecal microbial transplantation (FMT) from healthy individuals to subjects with active CD.

METHODS

We performed a prospective open-label study (uncontrolled) of FMT from healthy donors to subjects with active CD. A single FMT was performed by colonoscopy. Recipients' microbial diversity, mucosal T-cell phenotypes, and clinical and inflammatory parameters were measured over 12 weeks, and safety over 26 weeks.

RESULTS

Nineteen subjects were treated with FMT and completed the study follow-up. Fifty-eight percent (11/19) demonstrated a clinical response (Harvey-Bradshaw Index decrease >3) following FMT. Fifteen subjects had sufficient pre/postfecal samples for analysis. A significant increase in microbial diversity occurred after FMT (P = 0.02). This was greater in clinical responders than nonresponders. Patients who experienced a clinical response demonstrated a significant shift in fecal microbial composition toward their donor's profile as assessed by the Bray-Curtis index at 4 weeks (P = 0.003). An increase in regulatory T cells (CD4CD25CD127lo) was also noted in recipients' lamina propria following FMT. No serious adverse events were noted over the 26-week study period.

CONCLUSIONS

In this open-label study, FMT led to an expansion in microbial bacterial diversity in patients with active CD. FMT was overall safe, although the clinical response was variable. Determining donor microbial factors that influence clinical response is needed before randomized clinical trials of FMT in CD.

Psoriasis and inflammatory bowel disease: links and risks

Psoriasis and the spectrum of inflammatory bowel diseases (IBD) are chronic, inflammatory, organotropic conditions. The epidemiologic coexistence of these diseases is corroborated by findings at the level of disease, biogeography, and intrafamilial and intrapatient coincidence. The identification of shared susceptibility loci and DNA polymorphisms has confirmed this correlation at a genetic level. The pathogenesis of both diseases implicates the innate and adaptive segments of the immune system. Increased permeability of the epidermal barrier in skin and intestine underlies the augmented interaction of allergens and pathogens with inflammatory receptors of immune cells. The immune response between psoriasis and IBD is similar and comprises phagocytic, dendritic, and natural killer cell, along with a milieu of cytokines and antimicrobial peptides that stimulate T-cells. The interplay between dendritic cells and Th17 cells appears to be the core dysregulated immune pathway in all these conditions. The distinct similarities in the pathogenesis are also reflected in the wide overlapping of their therapeutic approaches. Small-molecule pharmacologic immunomodulators have been applied, and more recently, biologic treatments that target proinflammatory interleukins have been introduced or are currently being evaluated. However, the fact that some treatments are quite selective for either skin or gut conditions also highlights their crucial pathophysiologic differences. In the present review, a comprehensive comparison of risk factors, pathogenesis links, and therapeutic strategies for psoriasis and IBD is presented. Specific emphasis is placed on the role of the immune cell species and inflammatory mediators participating in the pathogenesis of these diseases.

Cytokine Networks and T-Cell Subsets in Inflammatory Bowel Diseases

Pathogenesis of the inflammatory bowel diseases (IBDs), such as ulcerative colitis (UC) and Crohn's disease (CD), involve proinflammatory changes within the microbiota, chronic immune-mediated inflammatory responses, and epithelial dysfunction. Converging data from genome-wide association studies, mouse models of IBD, and clinical trials indicate that cytokines are key effectors of both normal homeostasis and chronic inflammation in the gut. Yet many questions remain concerning the role of specific cytokines in different IBDs within distinct regions of the gut, and regarding cellular mechanisms of action. In this article, we review current and emerging concepts concerning the role of cytokines in IBD with a focus on immune regulation, T cell subsets, and potential clinical applications.

Cytokine Networks and T-Cell Subsets in Inflammatory Bowel Diseases

Pathogenesis of the inflammatory bowel diseases (IBDs), such as ulcerative colitis (UC) and Crohn's disease (CD), involve proinflammatory changes within the microbiota, chronic immune-mediated inflammatory responses, and epithelial dysfunction. Converging data from genome-wide association studies, mouse models of IBD, and clinical trials indicate that cytokines are key effectors of both normal homeostasis and chronic inflammation in the gut. Yet many questions remain concerning the role of specific cytokines in different IBDs within distinct regions of the gut, and regarding cellular mechanisms of action. In this article, we review current and emerging concepts concerning the role of cytokines in IBD with a focus on immune regulation, T cell subsets, and potential clinical applications.

The Th17/Treg Immune Imbalance in Ulcerative Colitis Disease in a Chinese Han Population

Objective. To investigate the Th17/Treg immune balance in the ulcerative colitis (UC) patients in a Chinese Han population. Methods. Ninety UC patients and 30 healthy subjects were enrolled. The serum IL-17 and TGF-β1 levels of these participants were measured with ELISA; the percentage of Th17 and Treg cells in peripheral blood was determined with flow cytometry. Results. In UC patients, the levels of IL-17 and Th17 were significantly higher compared with healthy subjects; the percentage of Th17 and IL-17 level in moderate and severe subgroup was significantly higher than in mild subgroup; a positive correlation existed between these two indexes and clinical activity index and endoscopic evaluation. TGF-β1 level and Treg cells in UC patients were lower than healthy subjects. TGF-β1 level in moderate and severe subgroup was lower than in mild subgroup. There was a negative linear correlation between Treg cells and clinical activity index, endoscopic evaluation. A positive correlation was detected between Treg cells and TGF-β1 level. Conclusions. Th17/Treg immune imbalance might play a crucial role in the development of UC. To induce the production of Treg cells and TGF-β1, inhibit the level of Th17 and IL-17, and thus recover the Th17/Treg immune balance might imply new therapeutic targets in UC management.

Disrupted regulatory T cell homeostasis in inflammatory bowel diseases

In the gut, where billions of non-self-antigens from the food and the microbiota are present, the immune response must be tightly regulated to ensure both host protection against pathogenic microorganisms and the absence of immune-related pathologies. It has been well documented that regulatory T cells (Tregs) play a pivotal role in this context. Indeed, Tregs are able to prevent excessive inflammation, which can lead to the rupture of intestinal homeostasis observed in inflammatory bowel diseases (IBDs). Both the worldwide incidence and prevalence of such diseases have increased throughout the latter part of the 20^th century. Therefore, it is crucial to understand how Tregs suppress the colitogenic immune cells to establish new treatments for patients suffering from IBDs. In this review, we will first summarize the results obtained in animal model studies that highlight the importance of Tregs in maintaining intestinal homeostasis and describe the specific suppressive mechanisms involved. Next, our current knowledge about Tregs contribution to human IBDs will be reviewed, as well as the current therapeutic perspective on using Tregs for clinical IBD treatment and the challenges that remain to be resolved to ensure both the safety and effectiveness of these therapies in targeting this critical immune-regulatory cell population.

Reduced Dendritic Cells Expressing CD200R1 in Children with Inflammatory Bowel Disease: Correlation with Th17 and Regulatory T Cells

Loss of tolerance of the adaptive immune system towards indigenous flora contributes to the development of inflammatory bowel diseases (IBD). Defects in dendritic cell (DC)-mediated innate and adoptive immune responses are conceivable. The aim of this study was to investigate the expression of the inhibitory molecules CD200R1 and their ligand CD200 on DCs, to clarify the role of the DCs in the pathogenesis of IBD. Thirty-seven pediatric IBD patients (23 with Crohn’s disease (CD) and 14 with ulcerative colitis (UC)) with mean age 13.25 ± 2.9 years were included. Fourteen age-matched healthy pediatric volunteers (five males and nine females) served as a control group (HC). The percentage of CD11c⁺ myeloid dendritic cells (mDCs) and CD123⁺ plasmacytoid DCs (pDCs) expressing CD200R1 and CD200 were evaluated in peripheral blood using flow cytometry and were correlated with routine biochemical, serological markers, serum levels of cytokines and with the percentages of circulating regulatory T cells (Treg) and CD4⁺ producing IL-17 (Th17). IBD patients showed a significant decrease in the percentage of pDCs and mDCs expressing CD200R1 compared to that of HC. Patients with UC showed increased expressions of the CD200 molecule on pDCs as compared to HC. DCs expressing CD200R1 were found to be correlated positively with Treg and negatively with TH17 and erythrocyte sedimentation rate (ESR). Our findings suggest that IBD is associated with dysregulation in the CD200R1/CD200 axis and that the decrease in DCs expressing CD200R1 may contribute to the imbalance of Th17 and Treg cells and in the pathogenesis of IBD.

Decrease of CD4(+) CD25(+) CD127(low) FoxP3(+) regulatory T cells with impaired suppressive function in untreated ulcerative colitis patients

Regulatory T (Treg) cells take part in immune homeostasis and play a pivotal role in maintaining peripheral tolerance. The aim of this study was to evaluate the frequency and function of Treg cells in active and untreated ulcerative colitis (UC) patients. Thirty-two subjects with newly diagnosed UC and 31 age-matched healthy controls were included in this survey. The frequency of Tregs was analyzed with flow cytometry using CD4, CD25, CD127 and FoxP3 markers. We used surface expression of CD4(+), CD25(+) and CD127(low) markers for isolation of a relatively pure Treg population. Suppressive activity of Tregs was determined by measuring their ability to inhibit the proliferation of T responder cells. UC patients had a lower frequency of CD4(+) CD25(+) CD127(low) FoxP3(+) Treg cells. Additionally, Treg cell-mediated suppression was lower in UC patients compared to controls. The frequency and suppressive capacity of Tregs and MFI of FoxP3 were inversely correlated with disease activity. These results suggest that CD4(+) CD25(+) CD127(low) FoxP3(+) Treg cells may contribute to immunopathogenesis of UC, and assessment of Treg cell frequency and function may have clinical value.