The expression patterns of Toll-like receptors in the ileal pouch mucosa of postoperative ulcerative colitis patients

Diagnosis and Medical Treatment of Acute and Chronic Idiopathic Pouchitis in Inflammatory Bowel Disease

Despite the decreased rates in inflammatory bowel disease (IBD) colectomies due to high advances in therapeutic options, a significant number of patients still require proctocolectomy with ileal pouch-anal anastomosis (IPPA) for ulcerative colitis (UC). Pouchitis is the most common complication in these patients, where up to 60% develop one episode of pouchitis in the first two years after UC surgery with IPAA with severe negative impact on their quality of life. Acute cases usually respond well to antibiotics, but 15% of patients will still develop a refractory disease that requires the initiation of advanced immunosuppressive therapies. For chronic idiopathic pouchitis, current recommendations suggest using the same therapeutic options as for IBD in terms of biologics and small molecules. However, the available data are limited regarding the effectiveness of different biologics or small molecules for the management of this condition, and all evidences arise from case series and small studies. Vedolizumab is the only biologic agent that has received approval for the treatment of adult patients with moderately to severely active chronic refractory pouchitis. Despite the fact that IBD treatment is rapidly evolving with the development of novel molecules, the presence of pouchitis represents an exclusion criterion in these trials. Recommendations for the approach of these conditions range from low to very low certainty of evidence, resulting from small randomized controlled trials and case series studies. The current review focuses on the therapeutic management of idiopathic pouchitis.

Exploring the therapeutic potential of cinnamoyl derivatives in attenuating inflammation in lipopolysaccharide-induced Caco-2 cells

Aim: In gastrointestinal (GI) diseases, lipopolysaccharide (LPS) exacerbates gut-barrier dysfunction and inflammation. Cinnamoyl derivatives show potential in mitigating LPS-induced inflammation.Materials & methods: We assessed intestinal epithelial barrier function using Trans-epithelial electrical resistance values and measured inflammatory mediators through real-time PCR and ELISA in Caco-2 cells.Results: LPS treatment increased IL-6, IL-1β, TNF-α, PGE2 and TRL4 expression in Caco-2 cells. Pre-treatment with DM1 (1 or 10 μM) effectively countered LPS-induced TLR4 overexpression and reduced IL-6, IL-1β, TNF-α and PGE2 levels.Conclusion: DM1 holds promise in regulating inflammation and maintaining intestinal integrity by suppressing TLR4 and inflammatory mediators in Caco-2 cells. These findings suggest a potential therapeutic avenue for GI diseases.

The aetiology of pouchitis in patients with inflammatory bowel disease

Restorative proctocolectomy with ileal pouch-anal anastomosis is a treatment option for patients with refractory ulcerative colitis. Pouchitis is the most common complication, representing a spectrum of diseases ranging from acute antibiotic-responsive type to chronic antibiotic-refractory. Early accurate diagnosis using a combined assessment of symptoms, endoscopy and histology is important for both treatment and prognostication. Most patients respond well to antibiotic therapy; however, management of chronic antibiotic-refractory pouchitis remains a challenge, and treatment options are based on small studies. Pouchitis is thought to be driven by the interaction between genetics, the immune system and the environment but as yet a causal relationship has yet to be identified. Further longitudinal assessment of the pouch integrating new technologies may help us understand the factors driving pouchitis. This review outlines the currently understood risk factors and aetiology of pouchitis.

Inulin alleviates perinatal 2-ethylhexyl diphenyl phosphate (EHDPHP) exposure-induced intestinal toxicity by reshaping the gut microbiota and suppressing the enteric-origin LPS/TLR4/NF-κb pathway in dams and pups

Organophosphorus flame retardants (OPFRs), such as 2-ethylhexyl diphenyl phosphate (EHDPHP), are ubiquitously used, leading to pervasive environmental contamination and human health risks. While associations between EHDPHP and health issues such as disruption of hormones, neurotoxic effects, and toxicity to reproduction have been recognized, exposure to EHDPHP during perinatal life and its implications for the intestinal health of dams and their pups have largely been unexplored. This study investigated the intestinal toxicity of EHDPHP and the potential for which inulin was effective. Dams were administered either an EHDPHP solution or a corn oil control from gestation day 7 (GD7) to postnatal day 21 (PND21), with inulin provided in their drinking water. Our results indicate that inulin supplementation mitigates damage to the intestinal epithelium caused by EHDPHP, restores mucus-secreting cells, suppresses intestinal hyperpermeability, and abates intestinal inflammation by curtailing lipopolysaccharide leakage through reshaping of the gut microbiota. A reduction in LPS levels concurrently inhibited the inflammation-associated TLR4/NF-κB pathway. In conclusion, inulin administration may ameliorate intestinal toxicity caused by EHDPHP in dams and pups by reshaping the gut microbiota and suppressing the LPS/TLR4/NF-κB pathway. These findings underscore the efficacy of inulin as a therapeutic agent for managing health risks linked to EHDPHP exposure.

Attenuation of Chronic Inflammation in Intestinal Organoids with Graphene Oxide-Mediated Tumor Necrosis Factor-α_Small Interfering RNA Delivery

Inflammatory bowel disease (IBD) is a chronic inflammatory disease of the gastrointestinal tract with a complex and multifactorial etiology, making it challenging to treat. While recent advances in immunomodulatory biologics, such as antitumor necrosis factor-α (TNF-α) antibodies, have shown moderate success, systemic administration of antibody therapeutics may lead to several adverse effects, including the risk of autoimmune disorders due to systemic cytokine depletion. Transient RNA interference using exogenous short interfering RNA (siRNA) to regulate target gene expression at the transcript level offers an alternative to systemic immunomodulation. However, siRNAs are susceptible to premature degradation and have poor cellular uptake. Graphene oxide (GO) nanoparticles have been shown to be effective nanocarriers for biologics due to their reduced cytotoxicity and enhanced bioavailability. In this study, we evaluate the therapeutic efficacy of GO mediated TNF-α_siRNA using in vitro models of chronic inflammation generated by treating murine small intestines (enteroids) and large intestines (colonoids) with inflammatory agents IL-1β, TNF-α, and LPS. The organotypic mouse enteroids and colonoids developed an inflammatory phenotype similar to that of IBD, characterized by impaired epithelial homeostasis and an increased production of inflammatory cytokines such as TNF-α, IL-1β, and IL-6. We assessed siRNA delivery to these inflamed organoids using three different GO formulations. Out of the three, small-sized GO with polymer and dendrimer modifications (smGO) demonstrated the highest transfection efficiency, which led to the downregulation of inflammatory cytokines, indicating an attenuation of the inflammatory phenotype. Moreover, the transfection efficiency and inflammation-ameliorating effects could be further enhanced by increasing the TNF-α_siRNA/smGO ratio from 1:1 to 3:1. Overall, the results of this study demonstrate that ex vivo organoids with disease-specific phenotypes are invaluable models for assessing the therapeutic potential of nanocarrier-mediated drug and biologic delivery systems.

Integrated Network Pharmacology, Molecular Docking and Animal Experiment to Explore the Efficacy and Potential Mechanism of Baiyu Decoction Against Ulcerative Colitis by Enema

Background

Baiyu Decoction (BYD), a clinical prescription of traditional Chinese medicine, has been proven to be valuable for treating ulcerative colitis (UC) by enema. However, the mechanism of BYD against UC remains unclear.

Purpose

A combination of bioinformatics methods including network pharmacology and molecular docking and animal experiments were utilized to investigate the potential mechanism of BYD in the treatment of UC.

Materials and Methods

Firstly, the representative compounds of each herb in BYD were detected by liquid chromatography-mass spectrometry. Subsequently, we predicted the core targets and potential pathways of BYD for treating UC through network pharmacology. And rat colitis model was established with dextran sodium sulfate. UC rats were subjected to BYD enema administration, during which we recorded body weight changes, disease activity index, and colon length to assess the effectiveness of BYD. Besides, quantitative real-time PCR, western blotting, ELISA and immunofluorescence were used to detect intestinal inflammatory factors, intestinal barrier biomarkers and TOLL-like receptor pathway in rats. Finally, the core components and targets of BYD were subjected to molecular docking so as to further validate the results of network pharmacology.

Results

A total of 41 active compositions and 203 targets related to BYD-UC were subjected to screening. The results of bioinformatics analysis showed that quercetin and kaempferol may be the main compounds. Additionally, AKT1, IL-6, TP53, TNF and IL-1β were regarded as potential therapeutic targets. KEGG results explained that TOLL-like receptor pathway might play a pivotal role in BYD protecting against UC. In addition, animal experiments and molecular docking validated the network pharmacology results. BYD enema treatment can reduce body weight loss, lower disease activity index score, reverse colon shortening, relieve intestinal inflammation, protect intestinal barrier, and inhibit TOLL-like receptor pathway in UC rats. Besides, molecular docking suggested that quercetin and kaempferol docked well with TLR4, AKT1, IL-6, TP53.

Conclusion

Utilizing network pharmacology, animal studies, and molecular docking, enema therapy with BYD was confirmed to have anti-UC efficacy by alleviating intestinal inflammation, protecting the intestinal barrier, and inhibiting the TOLL-like receptor pathway. Researchers should focus not only on oral medications but also on the rectal administration of medications in furtherance of the cure of ulcerative colitis.

Gut Microbiota, Inflammatory Bowel Disease, and Cancer: The Role of Guardians of Innate Immunity

Inflammatory bowel diseases (IBDs) are characterized by a persistent low-grade inflammation that leads to an increased risk of colorectal cancer (CRC) development. Several factors are implicated in this pathogenetic pathway, such as innate and adaptive immunity, gut microbiota, environment, and xenobiotics. At the gut mucosa level, a complex interplay between the immune system and gut microbiota occurs; a disequilibrium between these two factors leads to an alteration in the gut permeability, called 'leaky gut'. Subsequently, an activation of several inflammatory pathways and an alteration of gut microbiota composition with a proliferation of pro-inflammatory bacteria, known as 'pathobionts', take place, leading to a further increase in inflammation. This narrative review provides an overview on the principal Pattern Recognition Receptors (PRRs), including Toll-like receptors (TLRs) and NOD-like receptors (NLRs), focusing on their recognition mechanisms, signaling pathways, and contributions to immune responses. We also report the genetic polymorphisms of TLRs and dysregulation of NLR signaling pathways that can influence immune regulation and contribute to the development and progression of inflammatory disease and cancer.

Risks Factors Associated with the Development of Crohn's Disease After Ileal Pouch-Anal Anastomosis for Ulcerative Colitis: A Systematic Review and Meta-Analysis

BACKGROUND

Following ileal pouch-anal anastomosis [IPAA] for ulcerative colitis [UC], up to 16% of patients develop Crohn's disease of the pouch [CDP], which is a major cause of pouch failure. This systematic review and meta-analysis aimed to identify preoperative characteristics and risk factors for CDP development following IPAA.

METHODS

A literature search of the MEDLINE, EMBASE, EMCare and CINAHL databases was performed for studies that reported data on predictive characteristics and outcomes of CDP development in patients who underwent IPAA for UC between January 1990 and August 2022. Meta-analysis was performed using random-effect models and between-study heterogeneity was assessed.

RESULTS

Seven studies with 1274 patients were included: 767 patients with a normal pouch and 507 patients with CDP. Age at UC diagnosis (weighted mean difference [WMD] -2.85; 95% confidence interval [CI] -4.39 to -1.31; p = 0.0003; I2 54%) and age at pouch surgery [WMD -3.17; 95% CI -5.27 to -1.07; p = 0.003; I2 20%) were significantly lower in patients who developed CDP compared to a normal pouch. Family history of IBD was significantly associated with CDP (odds ratio [OR] 2.43; 95% CI 1.41-4.19; p = 0.001; I2 31%], along with a history of smoking [OR 1.80; 95% CI 1.35-2.39; p < 0.0001; I2 0%]. Other factors such as sex and primary sclerosing cholangitis were found not to increase the risk of CDP.

CONCLUSIONS

Age at UC diagnosis and pouch surgery, family history of IBD and previous smoking have been identified as potential risk factors for CDP post-IPAA. This has important implications towards preoperative counselling, planning surgical management and evaluating prognosis.

Exploring the molecular mechanism of comorbidity of autism spectrum disorder and inflammatory bowel disease by combining multiple data sets

BACKGROUND

Autism spectrum disorder (ASD) is a neurodevelopmental disorder that is difficult to diagnose. Inflammatory bowel disease (IBD) is a common chronic digestive disease. Previous studies have shown a potential correlation between ASD and IBD, but the pathophysiological mechanism remains unclear. The purpose of this research was to examine the biological mechanisms underlying the differentially expressed genes (DEGs) of ASD and IBD using bioinformatics tools.

METHODS

Limma software was used to evaluate the DEGs between ASD and IBD. The GSE3365, GSE18123, and GSE150115 microarray data sets were acquired from the Gene Expression Omnibus (GEO) database. We then performed 6 analyses, namely, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) functional annotation; weighted gene coexpression network analysis; correlation analysis of hub genes with autophagy, ferroptosis and immunity; transcriptional regulation analysis of hub genes; single-cell sequencing analysis; and potential therapeutic drug prediction.

RESULTS

A total of 505 DEGs associated with ASD and 616 DEGs associated with IBD were identified, and 7 genes overlapped between these sets. GO and KEGG analyses revealed several pathways enriched in both diseases. A total of 98 common genes related to ASD and IBD were identified by weighted gene coexpression network analysis (WGCNA), and 4 hub genes were obtained by intersection with the 7 intersecting DEGs, which were PDGFC, CA2, GUCY1B3 and SDPR. We also found that 4 hub genes in the two diseases were related to autophagy, ferroptosis or immune factors. In addition, motif-TF annotation analysis showed that cisbp__M0080 was the most relevant motif. We also used the Connectivity Map (CMap) database to identify 4 potential therapeutic agents.

CONCLUSION

This research reveals the shared pathogenesis of ASD and IBD. In the future, these common hub genes may provide new targets for further mechanistic research as well as new therapies for patients with ASD and IBD.

Serum amyloid protein A in inflammatory bowel disease: from bench to bedside

Inflammatory bowel diseases (IBD) is featured by gastrointestinal inflammation and a disease course with alternating recurrence and remission. The global burden caused by IBD has significantly boosted in recent years, necessitating treatment optimization. Serum amyloid A (SAA) is a class of 104 amino acid conservative acute-phase proteins, which is essential in immune-mediated inflammatory processes, like IBD. The SAA monomeric structure is composed of four α-helical regions and a C-terminal amorphous tail. Its disordered structure enables multiple bindings to different ligands and permits multiple functions. It has been proven that SAA has dual roles in the inflammatory process. SAA stimulates the pro-inflammatory cytokine expression and promotes the pathogenic differentiation of TH17 cells. In addition, SAA can remove toxic lipids produced during inflammatory responses and membrane debris from dead cells, redirect HDL, and recycle cholesterol for tissue repair. In IBD, SAA acts on gut epithelium barriers, induces T-cell differentiation, and promotes phagocytosis of Gram-negative bacteria. Owing to the tight connection between SAA and IBD, several clinical studies have taken SAA for a biomarker for diagnosis, assessing disease activity, and predicting prognosis in IBD. Furthermore, 5-MER peptide, a drug specifically targeting SAA, has shown anti-inflammatory effects in some SAA-dependent animal models, providing novel insights into the therapeutic targets of IBD.

Intestinal Absorption and Anti-Inflammatory Effects of Siphonein, a Siphonaxanthin Fatty Acid Ester from Green Algae

Siphonein is a C19 acylated siphonaxanthin found in some edible green algae (e.g., Codium fragile and Caulerpa lentillifera). Although the content of siphonein in these green algae is similar to or higher than that of siphonaxanthin, studies of health-related biological activity of siphonein are much less than those of siphonaxanthin. Given the difference in the position of the acyl chain, one cannot infer intestinal absorption of siphonein from other general carotenoid fatty acid esters. In this study, we first investigated the intestinal absorption of siphonein using mouse and cell culture models. A small amount of siphonein was detected in the plasma of treated mice, and its concentration was higher than that of siphonaxanthin (i.e., the hydrolyzed product of ingested siphonein) from 1 to 6 h after administration. Pharmacological inhibition tests with differentiated Caco-2 cells showed that Nieman-Pick C1-like 1-mediated facilitated diffusion was involved in the cellular uptake of siphonein. These results indicate that, unlike general carotenoid fatty acid esters, siphonein can be absorbed without hydrolysis. We also evaluated the anti-inflammatory effect of siphonein in differentiated Caco-2 cells. Siphonein pretreatment modulated lipopolysaccharide-induced cellular lipidome alterations and suppressed mRNA expression of proinflammatory chemokines, CXCL8 protein release, and activation of NF-κB. This study provides new insights into the absorption processes of carotenoids and shows the anti-inflammatory effect of siphonein for the first time.

Increased expression of CB2 receptor in the intestinal biopsies of children with inflammatory bowel disease

OBJECTIVES

The Cannabinoid Receptor type 2 (CB2) is involved in inflammation and immune cell modulation. In previous studies, we demonstrated the association between the CNR2 rs35761398 polymorphism and the risk for pediatric inflammatory bowel disease (IBD). In this study, we analyzed the intestinal biopsies from Crohn disease (CD) and ulcerative colitis (UC) pediatric patients at the diagnosis to evaluate the expression of CB2 and several factors associated with IBD inflammatory pathways.

METHODS

We enrolled five patients with CD, five with UC, and five controls (CTR). We analyzed ileum and rectum biopsies from patients of each group evaluating the expression of CB2, Toll-like receptor 4, interleukin-6, and interleukin-1β by western blot and immunofluorescence.

RESULTS

Western blot analysis showed a significant increase of CB2 in the CD ileum and in the UC rectum biopsies and an increase of TLR4 in the UC rectum. We also observed a significant over-expression of the IL-6 in UC rectum. The immunofluorescence analysis confirmed western blot data, showing also a T-lymphocytes infiltration colocalized with CB2 expression in the CD ileum and UC rectum.

CONCLUSIONS

Our results show an upregulation of CB2 in pediatric IBD, which might have implications for drug discovery.

IMPACT

The Cannabinoid Receptor type 2 (CB2) is involved in the inflammation and modulation of the immune response in pediatric inflammatory bowel disease (IBD). CB2 receptor is more expressed in the inflamed intestine of pediatric IBD patients. CB2 could be used as a potential therapeutic target to reduce IBD-related inflammatory state in childhood.

Soy Lecithin in High-Fat Diets Exerts Dual Effects on Adipose Tissue Versus Ileum

SCOPE

Lipopolysaccharides and their transporters, LBP and sCD14, are involved in systemic inflammation following a high-fat diet. Natural emulsifiers such as soy lecithin, rich in soybean polar lipids (SPL), are often used by the food industry but little is known about effects of associating SPL with different oils.

METHODS AND RESULTS

Thus, this study investigates the effects of 4 weeks feeding of palm (P) or rapeseed (R) oil-enriched diets with or without SPL in mice, on white adipose tissue (WAT) inflammation, on ileum permeability, and on microbiota composition. When SPL are associated with rapeseed oil, a greater gene expression of leptin and inflammation in WAT is observed compared to P-SPL. In ileum, R-SPL group results in a lower expression of TLR4, IAP that detoxify bacterial LPS and tight junction proteins than R group. In turn, the gene expression of Reg3β and Reg3γ, which have antimicrobial activity, is higher in ileum of R-SPL group than in R group. SPL in rapeseed oil increases specific bacterial species belonging to Lachnospiraceae, Alistipes, and Bacteroidales.

CONCLUSION

The incorporation of SPL in a diet with rapeseed oil exerts differential effect on WAT and ileum, with respectively an inflammation of WAT and an antimicrobial activity in ileum, associated with specific microbiota changes.

Sophorolipids produced by Yarrowia lipolytica grown on Moringa oleifera oil cake protect against acetic acid-induced colitis in rats: impact on TLR-4/p-JNK/NFκB-p65 pathway

OBJECTIVES

Toll-like receptor-4 (TLR-4) activation plays a major role in triggering oxidative stress (OS) and inflammation implicated in the pathogenesis of ulcerative colitis (UC). Due to sophorolipids (SLs) antioxidant and anti-inflammatory properties, they are interestingly becoming more valued for their potential effectiveness in treating a variety of diseases. This study was designed to explore the effect of SLs produced by microbial conversion of Moringa oleifera oil cake using isolated yeast Yarrowia lipolytica against UC induced by acetic acid (AA) in rats.

METHODS

The produced SLs were identified by FTIR, 1H NMR and LC-MS/MS spectra, and administered orally for 7 days (200 mg/kg/day) before AA (2 ml, 4% v/v) to induce UC intrarectally on day eight. Biochemically, the levels of TLR-4, c-Jun N-terminal kinase (JNK), nuclear factor kappa B-p65 (NFκB-p65), interleukin-1beta (IL-1β), malondialdehyd, glutathione, Bax/Bcl2 ratio and the immunohistochemical evaluation of inducible nitric oxide synthase and caspase-3 were assayed.

KEY FINDINGS

SLs significantly reduced OS, inflammatory and apoptotic markers in AA-treated rats, almost like the reference sulfasalazine.

CONCLUSIONS

This study provided a novel impact for SLs produced by microbial conversion of M. oleifera oil cake against AA-induced UC in rats through hampering the TLR-4/p-JNK/NFκB-p65 signalling pathway.

Therapeutic Potential of Bioactive Components from Scutellaria baicalensis Georgi in Inflammatory Bowel Disease and Colorectal Cancer: A Review

Scutellaria baicalensis Georgi (SBG), an herbal medicine with various biological activities, including anti-inflammatory, anticancer, antiviral, antibacterial, and antioxidant activities, is effective in treatment of colitis, hepatitis, pneumonia, respiratory infections, and allergic diseases. This herbal medicine consists of major active substances, such as baicalin, baicalein, wogonoside, and wogonin. Inflammatory bowel disease (IBD) comprises a group of inflammatory conditions of the colon and small intestine, with Crohn's disease and ulcerative colitis being the main types. IBD can lead to serious complications, such as increased risk of colorectal cancer (CRC), one of the most common cancers worldwide. Currently, there is no cure for IBD, and its incidence has been increasing over the past few decades. This review comprehensively summarizes the efficacy of SBG in IBD and CRC and may serve as a reference for future research and development of drugs for IBD and cancer treatment.

Gut microbiota and transcriptome profiling revealed the protective effect of aqueous extract of Tetrastigma hemsleyanum leaves on ulcerative colitis in mice

Tetrastigma hemsleyanum, a traditional Chinese medicinal plant, possesses various biological activities, including anti-inflammatory and immunomodulatory functions. The purpose of this study was to determine the alleviating effect of the water extract of Tetrastigma hemsleyanum leaves (THLW) on ulcerative colitis (UC) and its relationship with gut microbiota. The administration of THLW significantly decreased the severity of dextran sulfate sodium (DSS)-induced intestinal damage, as demonstrated by the stabilization of body weight and colon length, and decreased disease activity index (DAI) and histological scores. THLW also decreased NF-κB protein expression in colon tissues and reduced the serum levels of IL-6, IL-1β, and TNF-α. Further co-housing experiment confirmed that the anti-UC effect of THLW was possibly by regulating the structure and composition of gut microbiota, including increasing the abundance of Oscillospiraceae, Prevotellaceae and Corynebacterium. Additionally, the expression of genes related to inflammation and immunity was also regulated by THLW treatment as evidenced by transcriptome analysis. These results suggested that the protective effect of THLW on DSS-induced colitis was mediated by alleviating inflammation and modulating the microbiota composition. This work proved the potent protective effects of THLW treatment on colitis and may have potential for UC relief.

Using Drosophila melanogaster as a suitable platform for drug discovery from natural products in inflammatory bowel disease

Inflammatory bowel disease (IBD) is a chronic and life-treating inflammatory disease that can occur in multiple parts of the human intestine and has become a worldwide problem with a continually increasing incidence. Because of its mild early symptoms, most of them will not attract people's attention and may cause more serious consequences. There is an urgent need for new therapeutics to prevent disease progression. Natural products have a variety of active ingredients, diverse biological activities, and low toxicity or side effects, which are the new options for preventing and treating the intestinal inflammatory diseases. Because of multiple genetic models, less ethical concerns, conserved signaling pathways with mammals, and low maintenance costs, the fruit fly Drosophila melanogaster has become a suitable model for studying mechanism and treatment strategy of IBD. Here, we review the advantages of fly model as screening platform in drug discovery, describe the conserved molecular pathways as therapetic targets for IBD between mammals and flies, dissect the feasibility of Drosophila model in IBD research, and summarize the natural products for IBD treatment using flies. This review comprehensively elaborates that the benefit of flies as a perfact model to evaluate the therapeutic potential of phytochemicals against IBD.

Exploration of Potential Gut Microbiota-Derived Biomarkers to Predict the Success of Fecal Microbiota Transplantation in Ulcerative Colitis: A Prospective Cohort in Korea

Background/Aims

Although fecal microbiota transplantation (FMT) has been proven as one of the promising treatments for patients with ulcerative colitis (UC), potential prognostic markers regarding the clinical outcomes of FMT remain elusive.

Methods

We collected fecal samples of 10 participants undergoing FMT to treat UC and those from the corresponding donors. We categorized them into two groups: responders and nonresponders. Sequencing of the bacterial 16S rRNA gene was conducted on the samples to explore bacterial composition.

Results

Analyzing the gut microbiota of patients who showed different outcomes in FMT presented a distinct microbial niche. Source tracking analysis showed the nonresponder group had a higher rate of preservation of donor microbiota, underscoring that engraftment degrees are not one of the major drivers for the success of FMT. At the phylum level, Bacteroidetes bacteria were significantly depleted (p<0.003), and three genera, including Enterococcus, Rothia, and Pediococcus, were enriched in the responder group before FMT (p=0.003, p=0.025, and p=0.048, respectively). Furthermore, we applied a machine learning algorithm to build a prediction model that might allow the prediction of FMT outcomes, which yielded an area under the receiver operating characteristic (ROC) curve of 0.844. Notably, the microbiota-based model was much better at predicting outcomes than the clinical features model (area under the ROC curve=0.531).

Conclusions

This study is the first to suggest the significance of indigenous microbiota of recipients as a critical factor. The result highlights that bacterial composition should be evaluated before FMT to select suitable patients and achieve better efficiency.

The Role of the Human Gut Microbiome in Inflammatory Bowel Disease and Radiation Enteropathy

The human gut microbiome plays a key role in regulating host physiology. In a stable state, both the microbiota and the gut work synergistically. The overall homeostasis of the intestinal flora can be affected by multiple factors, including disease states and the treatments given for those diseases. In this review, we examine the relatively well-characterised abnormalities that develop in the microbiome in idiopathic inflammatory bowel disease, and compare and contrast them to those that are found in radiation enteropathy. We discuss how these changes may exert their effects at a molecular level, and the possible role of manipulating the microbiome through the use of a variety of therapies to reduce the severity of the underlying condition.

Different panel of toll-like receptors expression during chronic Schistosoma mansoni infection in experimental animals

BACKGROUND

Many studies have reported the immunomodulatory effect of helminths to avoid the lethal immunopathology. During schistosomiasis, the immune response is orchestrated by toll-like receptors (TLRs). Modulating TLRs can alter the function of antigen presentation cells with the shift of the host's Th1 response to a dominant regulatory Th2 response. The objective of our study was to clarify which TLRs are related to the immune response of chronic Schistosoma infection.

METHODS

The study animals were divided into two groups; group I: uninfected mice; control group and group II: Schistosoma mansoni infected mice. mRNA expression of TLR2, 3, 4, 7, and 9 in different organs (liver, large intestine, and spleen) were assessed on day 90 post-infection.

RESULTS

TLR gene expression has changed depending on the tissue studied as the mRNA level of TLR2, TLR7, and TLR9 were significantly upregulated in all examined organs while TLR3 expression showed only significant upregulation in the liver of infected mice. On the other hand, TLR4 expression was significantly upregulated in the liver while significantly downregulated in the large intestine.

CONCLUSION

This study provides a better understanding of TLRs profile in different organs against S. mansoni parasites during the chronic phase of infection.

Pharmacological Effects of Polyphenol Phytochemicals on the Intestinal Inflammation via Targeting TLR4/NF-κB Signaling Pathway

TLR4/NF-κB is a key inflammatory signaling transduction pathway, closely involved in cell differentiation, proliferation, apoptosis, and pro-inflammatory response. Toll like receptor 4 (TLR4), the first mammalian TLR to be characterized, is the innate immune receptor that plays a key role in inflammatory signal transductions. Nuclear factor kappa B (NF-κB), the TLR4 downstream, is the key to accounting for the expression of multiple genes involved in inflammatory responses, such as pro-inflammatory cytokines. Inflammatory bowel disease (IBD) in humans is a chronic inflammatory disease with high incidence and prevalence worldwide. Targeting the TLR4/NF-κB signaling pathway might be an effective strategy to alleviate intestinal inflammation. Polyphenol phytochemicals have shown noticeable alleviative effects by acting on the TLR4/NF-κB signaling pathway in intestinal inflammation. This review summarizes the pharmacological effects of more than 20 kinds of polyphenols on intestinal inflammation via targeting the TLR4/NF-κB signaling pathway. We expected that polyphenol phytochemicals targeting the TLR4/NF-κB signaling pathway might be an effective approach to treat IBD in future clinical research applications.

Phenotyping of Fecal Microbiota of Winnie, a Rodent Model of Spontaneous Chronic Colitis, Reveals Specific Metabolic, Genotoxic, and Pro-inflammatory Properties

Winnie, a mouse carrying a missense mutation in the MUC2 mucin gene, is a valuable model for inflammatory bowel disease (IBD) with signs and symptoms that have multiple similarities with those observed in patients with ulcerative colitis. MUC2 mucin is present in Winnie, but is not firmly compacted in a tight inner layer. Indeed, these mice develop chronic intestinal inflammation due to the primary epithelial defect with signs of mucosal damage, including thickening of muscle and mucosal layers, goblet cell loss, increased intestinal permeability, enhanced susceptibility to luminal inflammation-inducing toxins, and alteration of innervation in the distal colon. In this study, we show that the intestinal environment of the Winnie mouse, genetically determined by MUC2 mutation, selects an intestinal microbial community characterized by specific pro-inflammatory, genotoxic, and metabolic features that could imply a direct involvement in the pathogenesis of chronic intestinal inflammation. We report results obtained by using a variety of in vitro approaches for fecal microbiota functional characterization. These approaches include Caco-2 cell cultures and Caco-2/THP-1 cell co-culture models for evaluation of geno-cytotoxic and pro-inflammatory properties using a panel of 43 marker RNAs assayed by RT-qPCR, and cell-based phenotypic testing for metabolic profiling of the intestinal microbial communities by Biolog EcoPlates. While adding a further step towards understanding the etiopathogenetic mechanisms underlying IBD, the results of this study provide a reliable method for phenotyping gut microbial communities, which can complement their structural characterization by providing novel functional information.

Incidence and Risk Factors of Cancer in the Anal Transitional Zone and Ileal Pouch following Surgery for Ulcerative Colitis and Familial Adenomatous Polyposis

Proctocolectomy with ileal pouch-anal anastomosis is the intervention of choice for ulcerative colitis and familial adenomatous polyposis requiring surgery. One of the long-term complications is pouch cancer, having a poor prognosis. The risk of high-grade dysplasia and cancer in the anal transitional zone and ileal pouch after 20 years is estimated to be 2 to 4.5% and 3 to 10% in ulcerative colitis and familial polyposis, respectively. The risk factors for ulcerative colitis are the presence of pre-operative dysplasia or cancer, disease duration > 10 years and severe villous atrophy. For familial polyposis, the risk factors are the number of pre-operative polyps > 1000, surgery with stapled anastomosis and the duration of follow-up. In the case of ulcerative colitis, a pouchoscopy should be performed annually if one of the following is present: dysplasia and cancer at surgery, primary sclerosing cholangitis, villous atrophy and active pouchitis (every 5 years without any of these factors). In the case of familial polyposis, endoscopy is recommended every year including chromoendoscopy. Even if anal transitional zone and ileal pouch cancers seldom occur following proctectomy for ulcerative colitis and familial adenomatous polyposis, the high mortality rate associated with this complication warrants endoscopic monitoring.

NF-κB signaling in inflammation and cancer

Since nuclear factor of κ-light chain of enhancer-activated B cells (NF-κB) was discovered in 1986, extraordinary efforts have been made to understand the function and regulating mechanism of NF-κB for 35 years, which lead to significant progress. Meanwhile, the molecular mechanisms regulating NF-κB activation have also been illuminated, the cascades of signaling events leading to NF-κB activity and key components of the NF-κB pathway are also identified. It has been suggested NF-κB plays an important role in human diseases, especially inflammation-related diseases. These studies make the NF-κB an attractive target for disease treatment. This review aims to summarize the knowledge of the family members of NF-κB, as well as the basic mechanisms of NF-κB signaling pathway activation. We will also review the effects of dysregulated NF-κB on inflammation, tumorigenesis, and tumor microenvironment. The progression of the translational study and drug development targeting NF-κB for inflammatory diseases and cancer treatment and the potential obstacles will be discussed. Further investigations on the precise functions of NF-κB in the physiological and pathological settings and underlying mechanisms are in the urgent need to develop drugs targeting NF-κB for inflammatory diseases and cancer treatment, with minimal side effects.

Evaluation of E. coli Nissle1917 derived metabolites in modulating key mediator genes of the TLR signaling pathway

Objective

Gut-microbiota plays key roles in many aspects like the health and illness of humans. It's well proved that modification of gut microbiota by probiotics is useful for improving inflammatory bowel disease (IBD) conditions. According to recent studies, different types of bacterial metabolites can affect immune cells and inflammation conditions. The present study aimed to evaluate the anti-inflammatory effects of metabolites of E. coli Nissle1917.

Results

The cell-free supernatant could modulate TNF-α production and affected many crucial mediators in the Toll-like receptor (TLR) signaling pathway. Also, supernatant showed significant dose-dependent properties in this regard. In this study, the TLR signaling pathway was found among probable mechanisms by which probiotics can affect inflammatory situations. These findings provide additional evidence on the use of probiotic metabolites for inhibiting and down-regulating numerous key mediator factors in the TLR signaling pathway. Aberrant or dysfunctional TLR signaling contributes to the development of acute and chronic intestinal inflammatory pathways in IBD. Therefore, finding a component that can affect this process might be considered for therapeutic targets in IBD patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13104-021-05568-x.

Chrysin Derivative CM1 and Exhibited Anti-Inflammatory Action by Upregulating Toll-Interacting Protein Expression in Lipopolysaccharide-Stimulated RAW264.7 Macrophage Cells

Although our previous study revealed that gamma-irradiated chrysin enhanced anti-inflammatory activity compared to intact chrysin, it remains unclear whether the chrysin derivative, CM1, produced by gamma irradiation, negatively regulates toll-like receptor (TLR) signaling. In this study, we investigated the molecular basis for the downregulation of TLR4 signal transduction by CM1 in macrophages. We initially determined the appropriate concentration of CM1 and found no cellular toxicity below 2 μg/mL. Upon stimulation with lipopolysaccharide (LPS), CM1 modulated LPS-stimulated inflammatory action by suppressing the release of proinflammatory mediators (cytokines TNF-α and IL-6) and nitric oxide (NO) and downregulated the mitogen-activated protein kinase (MAPK) and nuclear factor-κB (NF-κB) signaling pathways. Furthermore, CM1 markedly elevated the expression of the TLR negative regulator toll-interacting protein (Tollip) in dose- and time-dependent manners. LPS-induced expression of cell surface molecules (CD80, CD86, and MHC class I/II), proinflammatory cytokines (TNF-α and IL-6), COX-2, and iNOS-mediated NO were inhibited by CM1; these effects were prevented by the knockdown of Tollip expression. Additionally, CM1 did not affect the downregulation of LPS-induced expression of MAPKs and NF-κB signaling in Tollip-downregulated cells. These findings provide insight into effective therapeutic intervention of inflammatory disease by increasing the understanding of the negative regulation of TLR signaling induced by CM1.

The role of medicinal products in the treatment of inflammatory bowel diseases (IBD) through inhibition of TLR4/NF-kappaB pathway

Inflammatory bowel disease (IBD) is a lifelong and recurrent disease of the gastrointestinal tract that afflicts many people in the world. Growing evidence has currently indicated that dysfunction of immune system, particularly toll-like receptors 4 (TLR4) signaling pathway dysfunction plays a pivotal part in the pathogenesis of IBD. TLR4 signaling is involved both in the pathogenesis and in the efficacy of treatment of IBD. There are some medicinal products and herbal medicines, which their role in the treatment of IBD through modulation of TLR4 signaling has been implicated. The purpose of this review article is to summarize those medicinal products and herbal medicines.

TLR2 Dimerization Blockade Allows Generation of Homeostatic Intestinal Macrophages under Acute Colitis Challenge

Recruited blood monocytes contribute to the establishment, perpetuation, and resolution of tissue inflammation. Specifically, in the inflamed intestine, monocyte ablation was shown to ameliorate colitis scores in preclinical animal models. However, the majority of intestinal macrophages that seed the healthy gut are also monocyte derived. Monocyte ablation aimed to curb inflammation would therefore likely interfere with intestinal homeostasis. In this study, we used a TLR2 trans-membrane peptide that blocks TLR2 dimerization that is critical for TLR2/1 and TLR2/6 heterodimer signaling to blunt inflammation in a murine colitis model. We show that although the TLR2 peptide treatment ameliorated colitis, it allowed recruited monocytes to give rise to macrophages that lack the detrimental proinflammatory gene signature and reduced potentially damaging neutrophil infiltrates. Finally, we demonstrate TLR blocking activity of the peptide on in vitro cultured human monocyte-derived macrophages. Collectively, we provide a significantly improved anti-inflammatory TLR2 peptide and critical insights in its mechanism of action toward future potential use in the clinic.

Curcumin and Intestinal Inflammatory Diseases: Molecular Mechanisms of Protection

Intestinal inflammatory diseases, such as Crohn’s disease, ulcerative colitis, and necrotizing enterocolitis, are becoming increasingly prevalent. While knowledge of the pathogenesis of these related diseases is currently incomplete, each of these conditions is thought to involve a dysfunctional, or overstated, host immunological response to both bacteria and dietary antigens, resulting in unchecked intestinal inflammation and, often, alterations in the intestinal microbiome. This inflammation can result in an impaired intestinal barrier allowing for bacterial translocation, potentially resulting in systemic inflammation and, in severe cases, sepsis. Chronic inflammation of this nature, in the case of inflammatory bowel disease, can even spur cancer growth in the longer-term. Recent research has indicated certain natural products with anti-inflammatory properties, such as curcumin, can help tame the inflammation involved in intestinal inflammatory diseases, thus improving intestinal barrier function, and potentially, clinical outcomes. In this review, we explore the potential therapeutic properties of curcumin on intestinal inflammatory diseases, including its antimicrobial and immunomodulatory properties, as well as its potential to alter the intestinal microbiome. Curcumin may play a significant role in intestinal inflammatory disease treatment in the future, particularly as an adjuvant therapy.

Regulatory T cells and Toll-like receptor 2 and 4 mRNA expression in infants with colic treated with Lactobacillus reuteri DSM17938

Regulatory T cells induce immune homeostasis and the expression of Toll like receptors (TLRs); subsequent inflammatory cytokine release may be involved. Recent studies have shown a microbial imbalance in the gut of colicky infants (with a prevalence of gram-negative bacteria, such as Escherichia coli), and accumulating evidence has shown the efficacy of a probiotic (Lactobacillus reuteri) in breastfed subjects, but the underlying mechanism remains undefined. The study enrolled 59 infants younger than 60 days, of whom 34 subjects had colic and 25 were healthy controls. With a double-blind, placebo-controlled randomised study performed in our unit from October 2016 to July 2017, infants with colic were randomly assigned to receive oral daily L. reuteri DSM17938 (1×108 cfu) or placebo for 28 days. Peripheral blood was collected to assess the expression of FoxP3, TLR2 and TLR4 mRNA using real-time TaqMan RT-PCR at baseline and after the study period. Our findings showed increased mRNA expression of the transcription factor forkhead box P3 (FoxP3) in infants treated with L. reuteri DSM 17938 for 28 days (P<0.009) and increased TLR2 and TLR4 mRNA expression in both treated and placebo subjects. After L. reuteri administration for 28 days in infants with colic, we observed a significant decrease in daily crying time (302.3±19.86 min/day on day 0 vs 76.75±22.15 min/day on day 28, P=0.001). This study provides evidence that the observed increase in FoxP3 expression and reduction in crying time might be responses to probiotic treatment, while the increase in TLR2 and TLR4 mRNA expression might be related to age. Exploiting these new findings may lead to an unprecedented level of therapeutic control over immune tolerance using probiotics.

Toll-like Receptors and Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is one relapsing and lifelong disease that affects millions of patients worldwide. Increasing evidence has recently highlighted immune-system dysfunction, especially toll-like receptors (TLRs)-mediated innate immune dysfunction, as central players in the pathogenesis of IBD. TLRs and TLR-activated signaling pathways are involved not only in the pathogenesis but also in the efficacy of treatment of IBD. By understanding these molecular mechanisms, we might develop a strategy for relieving the experience of long-lasting suffering of those patients and improving their quality of life. The purpose of this review article is to summarize the potential mechanisms of TLR signaling pathways in IBD and the novel potential therapeutic strategies against IBD.

TLR2 and interleukin-10 are involved in Bacteroides fragilis-mediated prevention of DSS-induced colitis in gnotobiotic mice

Background and aims

Bacteroides fragilis (BF) are Gram-negative anaerobe symbionts present in the colon. Recent studies have reported the beneficial role of BF in maintaining intestinal homeostasis, stimulating host immunologic development, and preventing infectious colitis caused by pathogenic bacteria. Our previous studies showed that monocolonization of germ-free mice with BF significantly reduced colon inflammations and damage.

Methods

In order to investigate the Toll-like receptor-2 (TLR2), TLR4, and interleukin 10 (IL-10) molecular signaling pathways involved in BF-mediated prevention of dextran sulfate sodium (DSS)-induced colitis. The wild-type (WT), TLR4, TLR2, and IL-10 knockout (^-/-) germ-free mice grown were with or without BF colonization for 28 days, and then administered 1% DSS in drinking water for 7 day to induce acute ulcerative colitis.

Results

We compared phenotypes such as weight loss, disease activity, intestinal histological scores, and immunohistochemistry for inflammatory cells. Unlike WT and TLR4^-/- mice, the severity of DSS-colitis did not improve in TLR2^-/- animals after BF colonization. The BF enhanced anti-inflammatory cytokines IL-10 expression and inhibited pro-inflammatory-related tumor necrosis factor (TNF-α) and IL-6 mRNA expression in both WT and TLR4^-/- mice. In contrast, the failed to up-regulated IL-10 and down-regulated the TNF-α and IL-6 in BF colonization TLR2^-/- mice. In addition, we further perform IL-10^-/- mice to clarify whether the BF through TLR2 /IL-10 pathway to alleviate DSS-colitis. There were no significant differences in colitis severity and pro-inflammatory related genes expression in the IL-10^-/- mice with or without BF colonization.

Conclusions

These results indicate the disease-preventing effects of BF in acute DSS-induced colitis may occur through the TLR2/IL-10 signal pathway.

Insights into the pathogenesis of ulcerative colitis from a murine model of stasis-induced dysbiosis, colonic metaplasia, and genetic susceptibility

Gut dysbiosis, host genetics, and environmental triggers are implicated as causative factors in inflammatory bowel disease (IBD), yet mechanistic insights are lacking. Longitudinal analysis of ulcerative colitis (UC) patients following total colectomy with ileal anal anastomosis (IPAA) where >50% develop pouchitis offers a unique setting to examine cause vs. effect. To recapitulate human IPAA, we employed a mouse model of surgically created blind self-filling (SFL) and self-emptying (SEL) ileal loops using wild-type (WT), IL-10 knockout (KO) (IL-10), TLR4 KO (T4), and IL-10/T4 double KO mice. After 5 wk, loop histology, host gene/protein expression, and bacterial 16s rRNA profiles were examined. SFL exhibit fecal stasis due to directional motility oriented toward the loop end, whereas SEL remain empty. In WT mice, SFL, but not SEL, develop pouchlike microbial communities without accompanying active inflammation. However, in genetically susceptible IL-10-deficient mice, SFL, but not SEL, exhibit severe inflammation and mucosal transcriptomes resembling human pouchitis. The inflammation associated with IL-10 required TLR4, as animals lacking both pathways displayed little disease. Furthermore, germ-free IL-10 mice conventionalized with SFL, but not SEL, microbiota populations develop severe colitis. These data support essential roles of stasis-induced, colon-like microbiota, TLR4-mediated colonic metaplasia, and genetic susceptibility in the development of pouchitis and possibly UC. However, these factors by themselves are not sufficient. Similarities between this model and human UC/pouchitis provide opportunities for gaining insights into the mechanistic basis of IBD and for identification of targets for novel preventative and therapeutic interventions.

Neutralization of pro-inflammatory monocytes by targeting TLR2 dimerization ameliorates colitis

Monocytes have emerged as critical driving force of acute inflammation. Here, we show that inhibition of Toll-like receptor 2(TLR2) dimerization by a TLR2 transmembrane peptide (TLR2-p) ameliorated DSS-induced colitis by interfering specifically with the activation of Ly6C(+) monocytes without affecting their recruitment to the colon. We report that TLR2-p directly interacts with TLR2 within the membrane, leading to inhibition of TLR2-TLR6/1 assembly induced by natural ligands. This was associated with decreased levels of extracellular signal-regulated kinases (ERK) signaling and reduced secretion of pro-inflammatory cytokines, such as interleukin (IL)-6, IL-23, IL-12, and IL-1β. Altogether, our study provides insights into the essential role of TLR2 dimerization in the activation of pathogenic pro-inflammatory Ly6C(hi) monocytes and suggests that inhibition of this aggregation by TLR2-p might have therapeutic potential in the treatment of acute gut inflammation.

Expression of Toll-like receptors in the mucosa of patients with ulcerative colitis

Patients with ulcerative colitis (UC) have a high risk of developing colorectal cancer. The aim of the present study was to evaluate the expression pattern of Toll-like receptors (TLRs) in the colonic mucosa of patients with UC. Colonic mucosal biopsy specimens were collected during colonoscopy from 30 patients with UC and 30 patients with normal findings as controls. The protein and mRNA expression levels of TLRs 1-4 and TLR9 were measured by immunohistochemistry and reverse transcription-quantitative polymerase chain reaction analysis, respectively. The results showed that the mRNA and protein expression of TLR2, TLR4 and TLR9, but not TLR1 and TLR3, was significantly increased in the colonic mucosa of patients with UC compared with that in the normal controls. TLR (TLR2, TLR4 and TLR9) immunoreactivity was found in the cytoplasm of epithelial cells in the mucosa, and occasionally in the endothelium of small vessels of the stromal tissues. In conclusion, TLR2, TLR4 and TLR9 expression may be important in the biological pathogenesis of UC. TLR alterations in the innate response system may contribute to the pathogenesis of UC.

Innate immune factors in the development and maintenance of pouchitis

BACKGROUND

Tight junction proteins (TJPs) and dendritic cells (DC) are critical in the pathogenesis of inflammatory bowel diseases. The ileal pouch formed by restorative proctocolectomy provides a unique human model for studying the pathogenesis of inflammatory bowel diseases. Data implicate the microbiota in the pathogenesis of pouchitis, while the role of innate immune factors remains unclear. We performed longitudinal and cross-sectional studies of patients after restorative proctocolectomy and assessed TJP and DC characteristics in the ileal pouch.

METHODS

Mucosal biopsies were taken from the ileal pouch of patients with ulcerative colitis (UC) and familial adenomatous polyposis (n = 8). Of patients with UC, one group (n = 5) was followed longitudinally over the first year after ileostomy closure, another group had pouchitis (n = 15), and another group no inflammation (n = 18). Dendritic cell phenotype and epithelial cell TJP expression were assessed using flow cytometric analysis.

RESULTS

Increased epithelial expression of the "pore-forming" TJP claudin 2, and DC expression of gut-homing markers CCR 9 and integrin β7, occurred early after ileostomy closure. In patients with UC with pouchitis, epithelial expression of ZO-1 and claudin 1 were reduced, DC were activated with increased CD40, and Toll-like receptor 4 expression increased. In pouchitis, DC expressing CCR 9 were decreased, whereas DC expressing β7 increased.

CONCLUSIONS

Abnormalities were found in TJP expression in the pouch of patients with UC, in particular, increased expression of the pore-forming claudin 2 as an early event in the development of pouch inflammation and an aberrant DC phenotype was characterized in the ileal pouch of patients with UC.

The intestinal microbiota and microenvironment in liver

The intestinal microbiome plays a significant role in the development of autoimmune diseases, in particular, inflammatory bowel diseases. But the interplay between the intestinal tract and the liver may explain the increased association with autoimmune liver diseases and inflammatory bowel diseases. The gut-liver axis involves multiple inflammatory cell types and cytokines, chemokines and other molecules which lead to the destruction of normal liver architecture. Triggers for the initiation of these events are unclear, but appear to include multiple environmental factors, including pathogenic or even commensal microbial agents. The variation in the gut microbiome has been cited as a major factor in the pathogenesis of autoimmune liver disease and even other autoimmune diseases. The unique positioning of the liver at the juncture of the peripheral circulation and the portal circulation augments the interaction between naïve T cells and other hepatic cells and leads to the disruption in the development of tolerance to commensal bacteria and other environmental agents. Finally, the innate immune system and in particular toll-like receptors play a significant role in the pathogenesis of autoimmune liver disease.

Relationship between pouch microbiota and pouchitis following restorative proctocolectomy for ulcerative colitis

Restorative proctocolectomy with ileal pouch-anal anastomosis (IPAA) has become the surgical treatment of choice for many patients with medically refractory ulcerative colitis (UC) and familial adenomatous polyposis (FAP). UC patients with IPAA (UC-IPAA) are, nevertheless, susceptible to inflammatory and noninflammatory sequelae such as pouchitis, which is only rarely noted in FAP patients with IPAA. Pouchitis is the most frequent long-term complication of UC-IPAA patients, with a cumulative prevalence of up to 50%. Although the aetiology of pouchitis remains unclear, accumulating evidence suggests that a dysbiosis of the pouch microbiota and an abnormal mucosal immune response are implicated in its pathogenesis. Studies using culture and molecular techniques have detected a dysbiosis of the pouch microbiota in patients with pouchitis. Risk factors, genetic associations, and serological markers suggest that interactions between the host immune response and the pouch microbiota underlie the aetiology of this idiopathic inflammatory condition. This systematic review focuses on the dysbiosis of the microbiota that inhabit the pouch in UC and FAP patients and its interaction with the mucosal immune system. A meta-analysis was not attempted due to the highly heterogeneous microbiota composition and the different detection methods used by the various studies. Although no specific bacterial species, genus, or family has as yet been identified as pathogenic, there is evidence that a dysbiosis characterized by decreased gut microbiota diversity in UC-IPAA patients may, in genetically predisposed subjects, lead to aberrant mucosal immune regulation triggering an inflammatory process.

Serologic markers associated with development of Crohn's disease after ileal pouch anal anastomosis for ulcerative colitis

BACKGROUND AND AIMS

One of the causes of pouch failure after ileal pouch anal anastomosis (IPAA) for ulcerative colitis (UC) is the development of de novo Crohn's disease (CD). Our aim was to clearly define factors associated with post-IPAA CD.

METHODS

We conducted a cross-sectional study to compare demographic, clinical, and serological characteristics of patients with and without post-IPAA CD. All subjects underwent testing for anti-neutrophil cytoplasm antibodies, anti-Saccaromyces cerevisiae antibodies, anti-outer membrane porin C antibodies, and anti-CBir1 flagellin (anti-CBir1). A multivariable model assessed factors associated with post-IPAA CD.

RESULTS

Thirty-nine subjects were enrolled in the study: 20 cases and 19 controls. Patients who developed post-IPAA CD were significantly younger (median 22 ± 9.9 vs. 30 ± 11.3, p = .027) at the time of UC diagnosis and exhibited more extraintestinal manifestations compared to controls (p = .023). No significant difference between the groups was found with respect to family history, smoking, duration of illness prior to colectomy, time to the onset of pouchitis, preoperative treatment, and indication for surgery. However, the post-operative serologic profile differed significantly with far more cases having elevated anti-CBir1 titers (p = .016, OR 8.81), the latter being the only independent predictor in the combined model.

CONCLUSIONS

Patients with Crohn's disease of the pouch were more likely to have elevated CBir1 antibodies titers than those with simple pouchitis and healthy pouches. The stability of the CBir1 antibodies (pre- and post-colectomy) must be further assessed to establish its value as an independent predictor for development of post-IPAA CD.

Pouchitis: what every gastroenterologist needs to know

Pouchitis is the most common complication among patients with ulcerative colitis who have undergone restorative proctocolectomy with ileal pouch-anal anastomosis. Pouchitis is actually a spectrum of diseases that vary in etiology, pathogenesis, phenotype, and clinical course. Although initial acute episodes typically respond to antibiotic therapy, patients can become dependent on antibiotics or develop refractory disease. Many factors contribute to the course of refractory pouchitis, such as the use of nonsteroidal anti-inflammatory drugs, infection with Clostridium difficile, pouch ischemia, or concurrent immune-mediated disorders. Identification of these secondary factors can help direct therapy.

Etiology of pouchitis

Restorative proctocolectomy with ileal-pouch anal anastomosis (RPC) is the operation of choice for ulcerative colitis (UC) patients requiring surgery. It is also used for patients with familial adenomatous polyposis (FAP). Pouchitis accounts for 10% of pouch failures. It is an idiopathic inflammatory condition that may occur in up to 50% of patients after RPC for UC. It is rarely seen in FAP patients after RPC. The etiology of pouchitis remains unclear. An overlap with UC is suggested by the frequency with which pouchitis affects patients with UC compared with FAP patients. There is significant clinical evidence implicating bacteria in the pathogenesis of pouchitis. Studies using culture and molecular methods demonstrate a dysbiosis of the pouch microbiota in pouchitis. Risk factors, genetic associations, and serological markers of pouchitis suggest that the interactions between the host immune responses and the pouch microbiota underlie the etiology of this idiopathic inflammatory condition. Here we present a detailed review of the data focusing on the pouch microbiota and the immune responses that support this hypothesis. We also discuss the contribution of luminal metabolic factors and the epithelial membrane in the etiology of this inflammatory process. The ileoanal pouch offers a unique opportunity to study the inter-relationships between the gut microbiota and host immune responses from before the onset of disease. For this reason the study of pouchitis could serve as a human model that significantly enhances our understanding of inflammatory bowel diseases in general.

Acute and chronic pouchitis--pathogenesis, diagnosis and treatment

Restorative proctocolectomy with ileal pouch-anal anastomosis has become the procedure of choice for the majority of patients with ulcerative colitis who require surgical treatment. Pouchitis, the most common long-term complication of the procedure, involves a spectrum of disease processes with heterogeneous risk factors, clinical features, disease courses and prognoses. In addition, clinical symptoms of pouchitis are not specific and often overlap with those of other inflammatory and functional pouch disorders, such as Crohn's disease of the pouch and irritable pouch syndrome. Pouchoscopy and biopsy, along with laboratory and radiographic evaluations, are often required for accurate diagnosis in patients with symptoms indicative of pouchitis. Dysbiosis has been implicated as a triggering factor for pouchitis, and concurrent infection with pathogens, such as Clostridium difficile, might contribute to disease relapse and exacerbation. Antibiotic therapy is the main treatment modality. However, the management of antibiotic-dependent and antibiotic-refractory pouchitis remains challenging. Secondary causes of pouchitis, such as ischaemia, NSAID use, the presence of concurrent primary sclerosing cholangitis and other systemic immune-mediated disorders, should be evaluated and properly managed.

Effect of ethyl pyruvate on high mobility group box 1 protein expression and serum cytokine levels in rats with experimental colitis

AIM: To evaluate the effect of ethyl pyruvate (EP) on the expression of high mobility group box 1 protein (HMGB1) and cytokine levels in rats with experimental colitis.

METHODS: Thirty-six rats were randomly and equally divided into three groups: blank control group, model control group, and EP treatment group. Experimental colitis was induced in mice by giving dextran sodium sulfate (DSS). The impact of EP on disease activity index (DAI) and histopathological score (HPS) in experimental colitis was evaluated. The expression of HMGB1 mRNA and protein was measured by reverse transcription-polymerase chain reaction (RT-PCR) and Western blot, respectively. Serum levels of TNF-a and IL-6 were determined by ELISA.

RESULTS: DAI and HPS were higher in the model control group than in the blank control group (7.20 ± 2.28 vs 0.45 ± 0.16, 13.60 ± 0.72 vs 6.4 ± 0.85, both P < 0.01). The expression levels of HMGB1 mRNA and protein were significantly higher in the model control group than in the blank control group (both P < 0.01). The levels of TNF-a and IL-6 in serum were also significantly higher in the model control group than in the blank control group (190.40 ± 24.55 vs 43.65 ± 8.79, 238.75 ± 26.58 vs 74.3 ± 7.92, both P < 0.01). Compared to the model control group, EP inhibited the body weight loss and occurrence of diarrhea as well as rectal bleeding in rats. DAI, HPS, TNF-a, IL-6 as well as the expression levels of HMGB1 mRNA and protein in the EP treatment group were significantly lower than those in the model control group (all P < 0.05).

CONCLUSION: The expression of HMGB1 is up-regulated in experimental colitis, which is closely related with the development and progression of experimental colitis. EP exerts significant therapeutic effects on DSS-induced experimental colitis in rats possibly by down-regulating the expression of HMGB1 and ameliorating the levels of inflammatory factors.

Innate immune environment in ileal pouch mucosa: α5 defensin up-regulation as predictor of chronic/relapsing pouchitis

Defensins are small cationic peptides with antibacterial activity expressed in Paneth cells (α-defensins) or generally in intestinal epithelial cells (β-defensins) that have a profound effect on gut microbiota. Chronic pouchitis, which occurs in 5% of patients after restorative proctocolectomy and can cause pouch failure, is associated to a significant increase of Clostridiaceae spp. The aim of this study was to gain further insight in the pathogenesis of pouch dysbiosis by exploring defensin expression. Thirty-two consecutive patients coming for follow-up endoscopy were recruited. On pouch biopsies, we cultured bacteria adherent to the mucosa and determined α- and β-defensins and toll-like receptor-4 and -2 mRNA by quantitative real-time RT-PCR. Serum and mucosal levels of IL-1β, IL-6 and TNF-α were measured with immunometric assays. Faecal lactoferrin was analysed by quantitative ELISA. After a median follow-up of 23 (IQR 20-24) months, the patients were contacted for a reassessment of current and past disease activity. During the follow-up, chronic/relapsing pouchitis was diagnosed in six patients. The mucosal level of α-5 and α-6 defensins correlated with chronic/relapsing pouchitis onset (τ = 0.30, p = 0.034 and τ = 0.28, p = 0.053, respectively). High levels of α-5 defensin resulted to be predictive of chronic/relapsing pouchitis [AUC = 74% (95% CI = 53-89%), p = 0.052]. Patients with high levels of α-5 and α-6 defensins had earlier pouchitis relapses (p = 0.009 and p = 0.034, respectively). High levels of α-5 defensin were associated to a significant risk of chronic/relapsing pouchitis [OR = 10.6 (95% CI = 1.2-97.6), p = 0.027]. At multivariate analysis, the mucosal levels of α-5 defensin and the number of CFU of mucosa-associated Clostridiaceae spp resulted to be independent predictors of chronic/relapsing pouchitis [β = 0.46 (0.18), p = 0.024 and β = 0.44 (0.18), p = 0.027, respectively]. In conclusion, chronic/relapsing pouchitis is associated to increased expression of mucosal HD-5 and to increased antimicrobial activity against Escherichia coli. In patients with chronic/relapsing pouchitis, HD-5 and TLR-4 over-expression is likely to create a hostile environment against Enterobacteriaceae, thus favouring Clostridiaceae spp by decreasing competing bacteria families.

Toll-like receptor 2 monoclonal antibody or/and Toll-like receptor 4 monoclonal antibody increase counts of Lactobacilli and Bifidobacteria in dextran sulfate sodium-induced colitis in mice

BACKGROUND AND AIM

The accurate pathogenesis of ulcerative colitis (UC) is not yet well understood. Recently, Toll-like receptor 2 (TLR2), TLR4 and gut microbial flora have been proved as playing important roles in the process of UC. This study was to evaluate the effect of TLR2 and TLR4 monoclonal antibodies on gut microbial flora in dextran sulfate sodium (DSS)-induced colitis in a mouse model.

METHODS

We evaluated the effects of the TLR2 and TLR4 monoclonal antibodies on the development of DSS-induced colitis. Clinical symptoms were evaluated by the disease activity index (DAI), while tissue samples were evaluated by histological scoring (HS). Meanwhile, the mucosal mRNA expressions of TLR2, TLR4, interferon-γ (IFN-γ), interleukin-4 (IL-4) and IL-17 were analyzed by Realtime polymerase chain reaction (PCR). The mucosal protein TRAF6, TAB1, P-IKK, P-P38α mitogen-activated protein kinase (MAPL) and c-jun expressions of the TLR2 and TLR4 signaling pathways were analyzed using Western blot. The mucosal nuclear factor kappa B (NF-κB) was analyzed using electrophoretic mobility shift assay. Fecal samples were obtained directly from the cecum for microbiological studies.

RESULTS

Expressions of TLR2 and TLR4 in colonic epithelial cells on DSS-induced colitis were much higher than normal ones. After the treatment with TLR2mAb and TLR4mAb, DAI and HS were decreased significantly. The UC model group showed a conspicuous increase of Escherichia coli and decreases of Lactobacillus spp. and Bifidobacterium spp. After being treated with TLR2mAb or/and TLR4mAb, Lactobacillus spp. and Bifidobacterium spp. increased to the normal level.

CONCLUSIONS

TLR2mAb and TLR4mAb can suppress the development of DSS-induced colitis and increase counts of Lactobacilli and Bifidobacteria.

Transcript levels of Toll-Like Receptors 5, 8 and 9 correlate with inflammatory activity in Ulcerative Colitis

Background

Dysregulation of innate immune response by Toll-Like Receptors (TLRs) is a key feature in Ulcerative Colitis (UC). Most studies have focused on TLR2, TLR3, and TLR4 participation in UC. However, few studies have explored other TLRs. Therefore, the aim of this study was to evaluate the mRNA profiles of TLR1 to 9 in colonic mucosa of UC patients, according to disease activity.

Methods

Colonic biopsies were taken from colon during colonoscopy in 51 patients with Ulcerative Colitis and 36 healthy controls. mRNA levels of TLR1 to 9, Tollip, inflammatory cytokines IL6 and TNF were assessed by RT-qPCR with hydrolysis probes. Characterization of TLR9 protein expression was performed by Immunohistochemistry.

Results

Toll-like receptors TLR8, TLR9, and IL6 mRNA levels were significantly higher in the colonic mucosa from UC patients (both quiescent and active) as compared to healthy individuals (p < 0.04). In the UC patients group the TLR2, TLR4, TLR8 and TLR9 mRNA levels were found to be significantly lower in patients with quiescent disease, as compared to those with active disease (p < 0.05), whereas TLR5 showed a trend (p = 0.06). IL6 and TNF mRNA levels were significantly higher in the presence of active disease and help to discriminate between quiescent and active disease (p < 0.05). Also, IL6 and TNF mRNA positively correlate with TLRs mRNA with the exception for TLR3, with stronger correlations for TLR5, TLR8, and TLR9 (p < 0.0001). TLR9 protein expression was mainly in the lamina propria infiltrate.

Conclusions

This study demonstrates that TLR2, TLR4, TLR8, and TLR9 expression increases in active UC patients, and that the mRNA levels positively correlate with the severity of intestinal inflammation as well as with inflammatory cytokines.

TLR2 and TLR4 up-regulation and colonization of the ileal mucosa by Clostridiaceae spp. in chronic/relapsing pouchitis

BACKGROUND

Chronic pouchitis, which can lead to pouch failure, occurs in approximately 5% of patients after restorative proctocolectomy for ulcerative colitis (UC). This work examined the interplay between the microbiota adherent to the ileal pouch mucosa and the mucosal immune system in chronic/relapsing pouchitis.

PATIENTS AND METHODS

Thirty-two consecutive patients attending our surgical gastroenterological department following restorative proctocolectomy with ileal pouch-anal anastomosis (IPAA) for UC were considered eligible candidates for this study. Biopsy samples of bacteria adherent to the mucosa were collected. TLR4 and TLR2 mucosal expression was measured by Real Time RT-PCR. Serum and mucosal IL-1β, IL-6, and TNF-α levels were assessed using immunometric assays. Fecal lactoferrin concentrations were determined by quantitative ELISA. After a median follow-up of 23 months (IQR 20-24 months) each patient underwent a global assessment of their clinical condition and disease activity status.

RESULTS

Six patients were diagnosed with relapsing/chronic pouchitis during the follow-up period. Mucosal TLR2 and TLR4 expression was higher in the chronic/relapsing pouchitis group than in the no or only one episode of pouchitis group (P = 0.036 and P = 0.016, respectively). The number of colony forming units (CFU) of mucosa-associated Clostridiaceae spp. was higher in the former than in the latter group (P = 0.031). Clostridiaceae were associated to a significant risk of chronic/relapsing pouchitis [OR: 14 (95% CI 0.887-224.021), P = 0.045].

CONCLUSION

Chronic/relapsing pouchitis is associated to higher mucosal TLR2 and TLR4 expression. Mucosal colonization by Clostridiaceae spp seems to play a role in the pathogenesis of chronic/relapsing pouchitis.