Tobacco and IBD: relevance in the understanding of disease mechanisms and clinical practice

Inflammatory Potential of the Diet and Risk of Crohn's Disease and Ulcerative Colitis

BACKGROUND

Association between dietary factors and the risk of developing inflammatory bowel disease (IBD) has been studied extensively. However, identification of deleterious dietary patterns merits further study.

AIM

To investigate the risk of developing Crohn's disease (CD) and ulcerative colitis (UC) according to the inflammatory score of the diet (ISD) in the multinational European Prospective Investigation into Cancer and Nutrition (EPIC) cohort.

METHODS

We used validated food frequency questionnaires collected at baseline to compute ISD scores. We estimated the association between ISD score and risks of CD and UC risks using Cox models stratified by centre, sex and age. We adjusted for smoking status, BMI, physical activity, energy intake, educational level and alcohol intake.

RESULTS

We included 394,255 individuals including 184 incident cases of CD and 459 of UC after median follow-up of 13.6 years (4,889,910 person-years). High ISD scores were associated with a higher risk of CD (fourth vs. first quartile-adjusted HR: 1.88, 95% CI: 1.14-3.10; p-trend < 0.01) but not of UC (adjusted HR: 0.85, 95% CI: 0.63-1.15; p-trend 0.21). For CD, this association was mainly observed for women (adjusted HR: 2.14, 95% CI: 1.17-3.91; p-trend < 0.01). On subgroup analyses, those differences were mainly driven by low intakes of fibre, mono-unsaturated fatty acids, vitamin C, magnesium, onion and alcohol.

CONCLUSIONS

A high ISD score is associated with a higher risk of developing CD but not UC. These results should be taken into account in high-risk populations.

Challenges in IBD Research 2024: Environmental Triggers

Environmental factors play an important role in inflammatory bowel diseases (IBD; Crohn's disease, [CD], ulcerative colitis [UC]). As part of the Crohn's & Colitis Challenges 2024 agenda, the Environmental Triggers workgroup summarized the progress made in the field of environmental impact on IBD since the last Challenges cycle in this document. The workgroup identified 4 unmet gaps in this content area pertaining to 4 broad categories: (1) Epidemiology; (2) Exposomics and environmental measurement; (3) Biologic mechanisms; and (4) Interventions and Implementation. Within epidemiology, the biggest unmet gaps were in the study of environmental factors in understudied populations including racial and ethnic minority groups and in populations witnessing rapid rise in disease incidence globally. The workgroup also identified a lack of robust knowledge of how environmental factors may impact difference stages of the disease and for different disease-related end points. Leveraging existing cohorts and targeted new prospective studies were felt to be an important need for the field. The workgroup identified the limitations of traditional questionnaire-based assessment of environmental exposure and placed high priority on the identification of measurable biomarkers that can quantify cross-sectional and longitudinal environmental exposure. This would, in turn, allow for identifying the biologic mechanisms of influence of environmental factors on IBD and understand the heterogeneity in effect of such influences. Finally, the working group emphasized the importance of generating high-quality data on effective environmental modification on an individual and societal level, and the importance of scalable and sustainable methods to deliver such changes.

Current Approach to Risk Factors and Biomarkers of Intestinal Fibrosis in Inflammatory Bowel Disease

Inflammatory bowel disease (IBD), especially Crohn's disease (CD), characterized by a chronic inflammatory process and progressive intestinal tissue damage, leads to the unrestrained proliferation of mesenchymal cells and the development of bowel strictures. Complications induced by fibrosis are related to high rates of morbidity and mortality and lead to a substantial number of hospitalizations and surgical procedures, generating high healthcare costs. The development of easily obtained, reliable fibrogenesis biomarkers is essential to provide an important complementary tool to existing diagnostic and prognostic methods in IBD management, guiding decisions on the intensification of pharmacotherapy, proceeding to surgical methods of treatment and monitoring the efficacy of anti-fibrotic therapy in the future. The most promising potential markers of fibrosis include cartilage oligomeric matrix protein (COMP), hepatocyte growth factor activator (HGFA), and fibronectin isoform- extra domain A (ED-A), as well as antibodies against granulocyte macrophage colony-stimulating factor (GM-CSF Ab), cathelicidin (LL-37), or circulatory miRNAs: miR-19a-3p and miR-19b-3p. This review summarizes the role of genetic predisposition, and risk factors and serological markers potentially contributing to the pathophysiology of fibrotic strictures in the course of IBD.

Smoking and colorectal neoplasia in patients with inflammatory bowel disease: Dose-effect relationship

BACKGROUND AND AIMS

Prior studies on the effect of smoking on the risk of colitis-associated colorectal neoplasia (CRN) have reported conflicting results. We aimed to further elucidate the association between smoking, including possible dose-effects, and the development of colorectal neoplasia in patients with inflammatory bowel disease (IBD).

METHODS

We performed a prospective multicenter cohort study including patients with colonic IBD enrolled in a surveillance program in four academic hospitals between 2011 and 2021. The effects of smoking status and pack-years at study entry on subsequent recurrent events of CRN (including indefinite, low- and high-grade dysplasia, and colorectal cancer [CRC]) were evaluated using uni- and multivariable Prentice, Williams, and Peterson total-time Cox proportional hazard models. Adjustment was performed for extensive disease, prior/index dysplasia, sex, age, first-degree relative with CRC, primary sclerosing cholangitis, and endoscopic inflammation.

RESULTS

In 501 of the enrolled 576 patients, at least one follow-up surveillance was performed after the study index (median follow-up 5 years). CRN occurred at least once in 105 patients. Ever smoking was not associated with recurrent CRN risk (adjusted hazard ratio [aHR] 1.04, 95% confidence interval [CI] 0.75-1.44), but an increasing number of pack-years was associated with an increased risk of recurrent CRN (aHR per 10 pack-years 1.17, 95% CI 1.03-1.32; p < 0.05). Separate analyses per IBD type did not reveal differences.

CONCLUSIONS

This study found that an increase in pack-years is associated with a higher risk of recurrent CRN in patients with IBD, independent of established CRN risk factors (NCT01464151).

Mechanism investigation of fermented egg-milk peptides on colonic inflammatory diseases: based on in vivo and in silico research

Fermented egg-milk peptides (FEMPs) could alleviate the symptoms of inflammatory diseases but the underlying regulating mechanism of effective ingredients is unclear now. Our research was designed to confirm the protective function of FEMP, then analyze the potential targets and pathways that could be regulated by digested FEMP (dFEMP). The results showed that FEMP could ease the inflammatory symptoms in the colon, repair the damage of inflammation, and decrease the level of pro-inflammatory cytokines (decreased by 31.81% TNF-α, 60.20% IL-1β, 85.65% IL-6). The results of in silico experiments revealed that dFEMP could influence many inflammation-related targets. Most targets affected the inflammation-related function and participated in the inflammatory signaling pathways, such as the T cell receptor (TCR) signaling pathway. Besides, molecular docking results revealed that hydrogen-bonding and salt bridges played vital roles in the dFEMP-target interactions. Combining in vivo experiments with in silico experiments, this study can prove a new theory for research between the bioactive peptides and inflammation.

Emerging Nanotechnologies and Microbiome Engineering for the Treatment of Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is characterized by the chronic inflammation of the gastrointestinal tract and impacts almost 7 million people across the globe. Current therapeutics are effective in treating the symptoms, but they often do not address the root cause or selectively target areas of inflammation. Notably, self-assembled nanoparticles show great promise as drug delivery systems for the treatment of IBD. Nanoparticles can be designed to survive the harsh gastric conditions and reach inflamed areas of the gastrointestinal tract. Oral drug delivery with nanoparticles can localize drugs to the impacted inflamed region using active and/or passive targeting and promote a high rate of drug dispersion in local tissues, thus reducing potential off-target toxicities. Since a dysregulated gut microbiome is implicated in the development and progression of IBD, it is also important to develop nanoparticles and biomaterials that can restore symbiotic microbes while reducing the proliferation of harmful microbes. In this review, we highlight recent advances in self-assembled nanosystems designed for addressing inflammation and dysregulated gut microbiomes as potential treatments for IBD. Nanoparticles have a promising future in improving the delivery of current therapeutics, increasing patient compliance by providing an oral method of medication, and reducing side effects. However, remaining challenges include scale-up synthesis of nanoparticles, potential side effects, and financial obstacles of clinical trials. It would be in the patients' best interest to continue research on nanoparticles in the pursuit of more effective therapeutics for the treatment of IBD.

Effects of hydrogen peroxide on endothelial function in three-dimensional hydrogel vascular model and regulation mechanism of polar protein Par3

Three-dimensional (3D) cell cultures better reflect the function of endothelial cells (ECs) than two-dimensional (2D) cultures. In recent years, studies have found that ECs cultured in a 3D luminal structure can mimic the biological characteristics and phenotypes of vascular ECs, thus making it more suitable for endothelial dysfunction research. In this study, we used a 3D model and 2D tissue culture polystyrene (TCP) to investigate the effects of cell polarity on hydrogen peroxide (H2O2)-induced endothelial dysfunction and its related mechanisms. We observed the cell morphology, oxidative stress, and barrier and endothelial function of human umbilical vein endothelial cells (HUVECs) in 3D and 2D cultures. We then used Illumina to detect the differentially expressed genes in the 3D-cultured HUVEC with and without H2O2 stimulation, using ClusterProfiler for Gene Ontology (GO) function enrichment analysis and Kyoto Encyclopaedia of Genes and Genomes (KEGG) pathway enrichment analysis of differentially expressed genes. Finally, we explored the role and mechanism of polar protein partitioning defective protein 3 (Par3) in the regulation of ECs. ECs were inoculated into the 3D hydrogel channel; after stimulation with H2O2, the morphology of HUVECs changed, the boundary was blurred, the expression of intercellular junction proteins decreased, and the barrier function of the EC layer was damaged. 3D culture increased the oxidative stress response of cells stimulated by H2O2 compared to 2D TCPs. The polarity-related protein Par3 and cell division control protein 42 (CDC42) were screened using bioinformatics analysis, and western blotting was used to verify the results. Par3 knockdown significantly suppressed claudin1 (CLDN1) and vascular endothelial cadherin (VE-cadherin). These results suggest that the polar protein Par3 can protect H2O2-induced vascular ECs from damage by regulating CLDN1 and VE-cadherin.

Cigarette Smoke Increases Risk for Colorectal Neoplasia in Inflammatory Bowel Disease

BACKGROUND & AIMS

Patients with inflammatory bowel disease are at increased risk of colorectal neoplasia (CRN) due to mucosal inflammation. As current surveillance guidelines form a burden on patients and healthcare costs, stratification of high-risk patients is crucial. Cigarette smoke reduces inflammation in ulcerative colitis (UC) but not Crohn's disease (CD) and forms a known risk factor for CRN in the general population. Due to this divergent association, the effect of smoking on CRN in IBD is unclear and subject of this study.

METHODS

In this retrospective cohort study, 1,386 IBD patients with previous biopsies analyzed and reported in the PALGA register were screened for development of CRN. Clinical factors and cigarette smoke were evaluated. Patients were stratified for guideline-based risk of CRN. Cox-regression modeling was used to estimate the effect of cigarette smoke and its additive effect within the current risk stratification for prediction of CRN.

RESULTS

153 (11.5%) patients developed CRN. Previously described risk factors, i.e. first-degree family member with CRN in CD (p-value=.001), presence of post-inflammatory polyps in UC (p-value=.005), were replicated. Former smoking increased risk of CRN in UC (HR 1.73; 1.05-2.85), whereas passive smoke exposure yielded no effect. For CD, active smoking (2.20; 1.02-4.76) and passive smoke exposure (1.87; 1.09-3.20) significantly increased CRN risk. Addition of smoke exposure to the current risk-stratification model significantly improved model fit for CD.

CONCLUSIONS

This study is the first to describe the important role of cigarette smoke in CRN development in IBD patients. Adding this risk factor improves the current risk stratification for CRN surveillance strategies.

Cholinergic immunomodulation in inflammatory bowel diseases

Inflammatory bowel diseases (IBD) are chronic intestinal disorders characterized by dysregulated immune responses to resident microbiota in genetically susceptible hosts. The activation of the cholinergic system has been proposed for the treatment of IBD patients according to its potential anti-inflammatory effect in vivo. The α-7-nicotinic-acetylcholine receptor (α7nAChR) is involved in the inhibition of inflammatory processes, modulating the production of cytokines, suppressing dendritic cells and macrophage activity, leading to the suppression of T cells. In this review, we address the most recent studies and clinical trials concerning cholinergic signaling and its therapeutic potential for inflammatory bowel diseases.

Microscopic colitis

Microscopic colitis (MC) is an inflammatory disease of the large intestine associated with urgent watery diarrhoea. MC may occur in people of all ages, although the disease primarily affects older women. Once believed to be rare, MC is now known to be a common cause of chronic watery diarrhoea in high-income countries, affecting 1 in 115 women and 1 in 286 men during their lifetime in Swedish population-based estimates. An inappropriate immune response to disturbances in the gut microenvironment is implicated in the pathogenesis of MC. Evidence also supports an underlying genetic basis for disease. The diagnosis of MC relies on clinical symptoms and microscopic assessment of colonic biopsy samples. MC is categorized histologically into collagenous colitis, lymphocytic colitis and their incomplete forms. The mainstay of treatment includes the use of budesonide, with or without adjunctive therapies, and withdrawal of offending drugs. Emerging studies suggest a role for biologicals and immunosuppressive therapies for the management of budesonide-refractory or budesonide-dependent disease. MC can have a substantial negative effect on patient quality of life. The outlook for MC includes a better understanding of the immune response, genetics and the microbiome in disease pathogenesis along with progress in disease management through robust clinical trials.

A Review of Inflammatory Bowel Disease: A Model of Microbial, Immune and Neuropsychological Integration

Objective: Inflammatory bowel diseases (IBDs) are complex chronic inflammatory disorders of the gastro-intestinal (GI) tract with uncertain etiology. IBDs comprise two idiopathic disorders: Crohn's disease (CD) and ulcerative colitis (UC). The aetiology, severity and progression of such disorders are still poorly understood but thought to be influenced by multiple factors (including genetic, environmental, immunological, physiological, psychological factors and gut microbiome) and their interactions. The overarching aim of this review is to evaluate the extent and nature of the interrelationship between these factors with the disease course. A broader conceptual and longitudinal framework of possible neuro-visceral integration, core microbiome analysis and immune modulation assessment may be useful in accurately documenting and characterizing the nature and temporal continuity of crosstalk between these factors and the role of their interaction (s) in IBD disease activity. Characterization of these interactions holds the promise of identifying novel diagnostic, interventions, and therapeutic strategies. Material and Methods: A search of published literature was conducted by exploring PubMed, EMBASE, MEDLINE, Medline Plus, CDSR library databases. Following search terms relating to key question were set for the search included: "Inflammatory bowel diseases," "gut microbiota," "psychological distress and IBD," "autonomic reactivity and IBD," "immune modulation," "chronic inflammation," "gut inflammation," "enteric nervous system," "gut nervous system," "Crohn's disease," "Ulcerative colitis", "depression and IBD", "anxiety and IBD", "quality of life in IBD patients," "relapse in IBDs," "remission in IBDs," "IBD disease activity," "brain-gut-axis," "microbial signature in IBD," "validated questionnaires in IBD," "IBD activity indices," "IBD aetiology," "IBDs and stress," "epidemiology of IBDs", "autonomic nervous system and gut inflammation", "IBD and environment," "genetics of IBDs," "pathways of immune response in IBDs," "sleep disturbances in IBD," "hypothalamic-pituitary-adrenal axis (HPA)," "sympatho-adrenal axis," "CNS and its control of gut function" "mucosal immune response," "commensal and pathogenic bacteria in the gut," "innate and adaptive immunity." Studies evaluating any possible associations between gut microbiome, psychological state, immune modulation, and autonomic function with IBDs were identified. Commonly cited published literatures with high quality research methodology/results and additional articles from bibliographies of recovered papers were examined and included where relevant. Results: Although there is a substantial literature identifying major contributing factors with IBD, there has been little attempt to integrate some factors over time and assess their interplay and relationship with IBD disease activity. Such contributing factors include genetic and environmental factors, gut microbiota composition and function, physiological factors, psychological state and gut immune response. Interdependences are evident across psychological and biological factors and IBD disease activity. Although from the available evidence, it is implausible that a single explanatory model could elucidate the interplay between such factors and the disease course as well as the sequence of the effect during the pathophysiology of IBD. Conclusion: Longitudinal monitoring of IBD patients and integrating data related to the contributing/risk factors including psychological state, physiological conditions, inflammatory/immune modulations, and microbiome composition/function, could help to explain how major factors associate and interrelate leading to exacerbation of symptoms and disease activity. Identifying the temporal trajectory of biological and psychosocial disturbances may also help to assess their effects and interdependence on individuals' disease status. Moreover, this allows greater insight into understanding the temporal progressions of subclinical events as potential ground for disease severity in IBD. Furthermore, understanding the interaction between these risk factors may help better interventions in controlling the disease, reducing the costs related to disease management, further implications for clinical practice and research approaches in addition to improving patients' mental health and quality of life.

Risk factors for ulcerative colitis-associated colorectal cancer: A retrospective cohort study

Inflammatory bowel disease is associated with an increased risk of colorectal cancer. The study aims to identify the risk factors for ulcerative colitis-colorectal cancer and to perform a survival curve analysis of the outcome.This retrospective cohort study included 254 patients from March 2016 to October 2017. Age, age at diagnosis, follow-up time, smoking status, and family history of colorectal cancer were analyzed as risk factors for colorectal cancer.The mean patient age was 46.6 ± 16.9 years; 5.5% of the patients were smokers and 49.6% had pancolitis. Six patients (2.36%) had colorectal cancer, which was associated with age at diagnosis (odds/hazard ratio 1.059 [95% confidence interval: 1.001-1.121]; P = .04), family history of colorectal cancer (12.992 [1.611-104.7]; P = .02), and follow-up time (0.665 [0.513-0.864]; P = .002). Active smoking was the main identified risk factor, after both logistic (8.477 [1.350-53.232]; P = .02) and Cox proportional-hazards (32.484 [2.465-428.1]; P = .008) regression analysis. The risk of colorectal cancer was 3.17% at 10 years and 4.26% at 20 years of follow-up.Active smoking and family history were identified as risk factors for colorectal cancer. These findings should aid the early identification of patients who require vigorous surveillance, and prevent exposure to risk factors.

Translational research into the effects of cigarette smoke on inflammatory mediators and epithelial TRPV1 in Crohn's disease

Crohn's disease is a pathological condition of the gastro-intestinal tract, causing severe transmural inflammation in the ileum and/or colon. Cigarette smoking is one of the best known environmental risk factors for the development of Crohn's disease. Nevertheless, very little is known about the effect of prolonged cigarette smoke exposure on inflammatory modulators in the gut. We examined the effect of cigarette smoke on cytokine profiles in the healthy and inflamed gut of human subjects and in the trinitrobenzene sulphonic acid mouse model, which mimics distal Crohn-like colitis. In addition, the effect of cigarette smoke on epithelial expression of transient receptor potential channels and their concurrent increase with cigarette smoke-augmented cytokine production was investigated. Active smoking was associated with increased IL-8 transcription in ileum of controls (p < 0,001; n = 18-20/group). In the ileum, TRPV1 mRNA levels were decreased in never smoking Crohn's disease patients compared to healthy subjects (p <0,001; n = 20/group). In the colon, TRPV1 mRNA levels were decreased (p = 0,046) in smoking healthy controls (n = 20/group). Likewise, healthy mice chronically exposed to cigarette smoke (n = 10/group) showed elevated ileal Cxcl2 (p = 0,0075) and colonic Kc mRNA levels (p = 0,0186), whereas TRPV1 mRNA and protein levels were elevated in the ileum (p = 0,0315). Although cigarette smoke exposure prior to trinitrobenzene sulphonic acid administration did not alter disease activity, increased pro-inflammatory cytokine production was observed in the distal colon (Kc: p = 0,0273; Cxcl2: p = 0,104; Il1-β: p = 0,0796), in parallel with the increase of Trpv1 mRNA (p < 0,001). We infer that CS affects pro-inflammatory cytokine expression in healthy and inflamed gut, and that the simultaneous modulation of TRPV1 may point to a potential involvement of TRPV1 in cigarette smoke-induced production of inflammatory mediators.

The impact of smoking on prevalence of psoriasis and psoriatic arthritis

Objectives

In this systematic literature review and meta-analysis, we aimed to investigate the impact of cigarette smoking on the prevalence and incidence of psoriasis and psoriatic arthritis (PsA).

Method

We performed a systematic literature review using the MEDLINE, EMBASE and Cochrane Central Register databases. The literature included publications from January 1980 to July 2019. The studies that provided clear information on the number of patients with ever smoking data were included in the meta-analysis.

Results

The systematic literature review identified 52 and 24 articles for the prevalence of smoking in psoriasis and PsA, respectively. Of these, 16 articles on psoriasis and three and four (general population and psoriasis, respectively) articles on PsA met the criteria and were included in the meta-analysis. The prevalence of ever smoking was increased in psoriasis compared with the general population (OR: 1.84; 95% CI: 1.4, 2.3). For PsA the prevalence of ever smoking was reduced in psoriasis patients (OR: 0.70; 95% CI: 0.60, 0.81), but not changed compared with the general population (OR: 1.10; 95% CI: 0.92, 1.32).

Conclusion

This meta-analysis showed that ever smoking increases the risk of psoriasis in the general population, but may reduce the risk of PsA in psoriasis patients. The latter may be also due to the collider effect. Whether smoking cessation neutralizes the risk of developing psoriasis requires a well-defined smoking data collection for the past history and this is currently unavailable in the literature.

Role of environmental factors in the pathogenesis of Crohn's disease: a critical review

PURPOSE

To review role of environmental factors in the pathogenesis of Crohn's disease.

METHODS

We systematically reviewed trials and systematic reviews using PubMed and Web of science databases. Here, we review the current information on the causative factors and mechanisms of CD, including smoking, exercise, diet, animal protein, breastfeeding, history of childhood infection and vaccination, oral contraceptives, and antibiotics of CD. We also highlight important knowledge gaps that need to be filled in order to advance the field of CD research.

RESULTS

Epidemiological studies have indicated the significance of environmental factors in the disease behavior and outcome of Crohn's disease (CD). There are a few recognized environmental factors, such as cigarette smoking, exercise, dietary habits, and breastfeeding, which are associated with the pathogenesis of CD. These factors are hypothesized to change the epithelial barrier function, which disturbs both the innate and adaptive immune systems and the intestinal flora. However, the effect of several risk factors, such as appendectomy and pharmaceutical use, differs across several studies, indicating the need for more rigorous research. Furthermore, few studies have examined effective interventions based on environmental factors that can improve disease outcomes. Recent studies have indicated that the pathogenesis of CD is related to environmental and genetic factors.

CONCLUSION

We review the current information on the causative factors and mechanisms of CD, including smoking, exercise, diet, animal protein, breastfeeding, history of childhood infection and vaccination, oral contraceptives, and antibiotics of CD. However, further studies are needed to understand knowledge gaps in the field of CD.

Body mass index and risk of inflammatory bowel disease: A systematic review and dose-response meta-analysis of cohort studies of over a million participants

The relationship between body mass index (BMI) and risk of inflammatory bowel disease (IBD) is controversial. We performed a dose-response meta-analysis to investigate the association between BMI and risk of incident ulcerative colitis (UC) and Crohn's disease (CD) using prospective cohort studies. A systematic search was conducted in MEDLINE/PubMed, SCOPUS, Cochrane, and Web of Science databases from inception to January 2019. DerSimonian and Laird random-effects model was used to estimate combined hazard ratios (HRs). Overall, 882 articles were screened, and 42 full-text articles were reviewed for inclusion using the study eligibility criteria. Five studies evaluated the association between BMI and IBD with 1 044 517 participants. Pooled results showed a significant association between participants affected by obesity and risk of CD (HR: 1.42, 95% CI: 1.18-1.71, I² : 0.00). There was a significant nonlinear association between BMI and risk of CD (P = .01, coeff = 0.5024). Pooled results did not show any significant association between being underweight and risk of UC (HR: 1.07, 95% CI: 0.96-1.19, I² : 0.00) or CD (HR: 1.11, 95% CI: 0.93-1.31, I² : 12.8). There was no difference in the risk for UC among participants affected by obesity compared with participants categorized as having normal BMI (HR: 0.96, 95% CI: 0.80-1.14, I² : 8.0). This systematic review and meta-analysis identified significant dose-response relationship between being affected by obesity, as a risk factor, and incidence of CD.

Dietary Composition and Effects in Inflammatory Bowel Disease

Dramatic changes in the environment and human lifestyle have been associated with the rise of various chronic complex diseases, such as inflammatory bowel disease (IBD). A dysbiotic gut microbiota has been proposed as a crucial pathogenic element, contributing to immune imbalances and fostering a proinflammatory milieu, which may be associated with disease relapses or even the initiation of IBD. In addition to representing important regulators of the mucosal immunity and the composition of the gut microbiota, food components have been shown to be potential environmental triggers of epigenetic modifications. In the context of chronic intestinal inflammation, dietary habits and specific food components have been implicated as important modulators of epigenetic mechanisms, including DNA methylation, which may predispose a person to the increased risk of the initiation and evolution of IBD. This review provides novel insights about how dietary factors may interact with the intestinal mucosa and modulate immune homeostasis by shaping the intestinal ecosystem, as well as the potential influence of diet in the etiopathogenesis and management of IBD.

Lung inflammation and disease: A perspective on microbial homeostasis and metabolism

It is now well appreciated that the human microbiome plays a significant role in a number of processes in the body, significantly affecting its metabolic, inflammatory, and immune homeostasis. Recent research has revealed that almost every mucosal surface in the human body is associated with a resident commensal microbiome of its own. While the gut microbiome and its role in regulation of host metabolism along with its alteration in a disease state has been well studied, there is a lacuna in understanding the resident microbiota of other mucosal surfaces. Among these, the scientific information on the role of lung microbiota in pulmonary diseases is currently severely limited. Historically, lungs have been considered to be sterile and lung diseases have only been studied in the context of bacterial pathogenesis. Recently however, studies have revealed a resilient microbiome in the upper and lower respiratory tracts and there is increased evidence on its central role in respiratory diseases. Knowledge of lung microbiome and its metabolic fallout (local and systemic) is still in its nascent stages and attracting immense interest in recent times. In this review, we will provide a perspective on lung-associated metabolic disorders defined for lung diseases (e.g., chronic obstructive pulmonary disease, asthma, and respiratory depression due to infection) and correlate it with lung microbial perturbation. Such perturbations may be due to altered biochemical or metabolic stress as well. Finally, we will draw evidence from microbiome and classical microbiology literature to demonstrate how specific lung morbidities associate with specific metabolic characteristics of the disease, and with the role of microbiome in this context. © 2018 IUBMB Life, 71(1):152-165, 2019.

Inflammatory Bowel Disease Etiology: Current Knowledge

Non-specific inflammatory bowel diseases (IBD) include Crohn’s disease (CD) and ulcerative colitis (UC). Both diseases are characterized by chronic inflammation of unclear etiology. The inflammatory bowel diseases incidence is continuously observed to rise. Colon inflammatory response is a physiological process which occurrence is indispensable as an organisms’ defense reaction. The inflammation may be caused by internal factors associated with body’s cells as well as external factors, such as infections and exposition for inflammatory agents. Until recently, IBD have been classified as autoimmune diseases, today they seem to be associated with gut barrier disorders or dysbiosis. Factors that predispose to inflammatory bowel diseases include: genetic factors, dysbiosis and so called western-type diet, natural components such as gluten and lactose. In addition, the development of the disease is favored by: cigarette smoking, phosphate, nanomolecules, sodium chloride, emulgents, carrageenan, carboxymethylcellulose, pollution, maltodextrin. IBD affects whole the body, causing serious medical consequences. Symptoms like anxiety and chronic stress, that occur commonly, can lead to depressive disorders. Quantitative and qualitative dietary deficiency caused by absorption disorders, may promote the occurrence of osteoporosis and osteopenia. In addition, dysbiosis coexisting with alterations in intestinal permeability can lead to the development of nonalcoholic fatty liver disease. IBD medical consequences include also systemic complications, associated with the extra gastrointestinal manifestations’ occurrence.

Cigarette smoke extract acts directly on CD4 T cells to enhance Th1 polarization and reduce memory potential

Although cigarette smoke is known to alter immune responses, whether and how CD4 T cells are affected is not well-described. We aimed to characterize how exposure to cigarette smoke extract impacts CD4 T cell effector generation in vitro under Th1-polarizing conditions. Our results demonstrate that cigarette smoke directly acts on CD4 T cells to impair effector expansion by decreasing division and increasing apoptosis. Furthermore, cigarette smoke enhances Th1-associated cytokine production and increases expression of the transcription factor T-bet, the master regulator of Th1 differentiation. Finally, we show that exposure to cigarette smoke extract during priming impairs the ability of effectors to form memory cells. Our findings thus demonstrate that cigarette smoke simultaneously enhances effector functions but promotes terminal differentiation of CD4 T cell effectors. This study may be relevant to understanding how smoking can both aggravate autoimmune symptoms and reduce vaccine efficacy.

Biological therapy and surgery rates in inflammatory bowel diseases - Data analysis of almost 1000 patients from a Hungarian tertiary IBD center

Inflammatory bowel diseases (IBD) [Crohn’s disease (CD) and ulcerative colitis (UC)], are chronic relapsing disorders of unknown etiology. The aim of this study was to determine demographic features, disease phenotypes, medical and surgical therapies in our IBD patients and to identify which parameters are in association with the need of surgery and/or biologic therapy. Data on demographic and clinical characteristics of the patients were analyzed from the IBD registry of the 1^st Department of Medicine, University of Szeged. The study period was between January 2007 and March 2015. Data of 911 IBD patients (428 CD, 483 UC) were analyzed. The median lag time between onset of symptoms and diagnosis proved to be significantly longer in UC than in CD (4.6 years vs. 2.1 years, p = 0.01). 40% of the patients received biological therapy, 301 patients underwent surgery required more frequently for CD than UC. Surgery was more common in CD patients with ileal location and penetrating behaviour. In UC, more severe disease onset predicted to unfavourable disease course. Higher proportion of surgery was shown in patient aged above 40 years in both CD and UC. Diagnostic delay of more than 1 year and appendectomy predicted to unfavourable disease outcome of both CD and UC. This analysis revealed that more than 1 year of diagnostic delay, disease activity at diagnosis in UC, CD, ileal location and penetrating behaviour are factors that may influence disease outcome. Use of thiopurines seemed to be protective in UC.

Bonferroni-Holm and permutation tests to compare health data: methodological and applicative issues

BACKGROUND

Statistical methodology is a powerful tool in the health research; however, there is wide accord that statistical methodologies are not usually used properly. In particular when multiple comparisons are needed, it is necessary to check the rate of false positive results and the potential inflation of type I errors. In this case, permutation testing methods are useful to check the simultaneous significance level and identify the most significant factors.

METHODS

In this paper an application of permutation tests, in the medical context of Inflammatory Bowel Diseases, is performed. The main goal is to assess the existence of significant differences between Crohn's Disease (CD) and Ulcerative Colitis (UC). The Sequentially Rejective Multiple Test (Bonferroni-Holm procedure) is used to find which of the partial tests are effectively significant and solve the problem of the multiplicity control.

RESULTS

Applying Non-Parametric Combination (NPC) Test for partial and combined tests we conclude that Crohn's Disease patients and Ulcerative Colitis patients differ between them for most examined variables. UC patients compared with the CD patients, have a higher diagnosis age, not show smoking status, proportion of patients treated with immunosuppressants or with biological drugs is lower than the CD patients, even if the duration of such therapies is longer. CD patients have a higher rate of re-hospitalization. Diabetes is more present in the sub-population of UC patients. Analyzing the Charlson score we can highlight that UC patients have a more severe clinical situation than CD patients. Finally, CD patients are more frequently subject to surgery compared to UC. Appling of the Bonferroni Holm procedure, which provided adjusted p-values, we note that only nine of the examined variables are statistically significant: Smoking habit, Immunosuppressive therapy, Surgery, Biological Drug, Diabetes, Adverse Events, Re-hospitalization, Gender and Duration of Immunosoppressive Therapy. Therefore, we can conclude that these are the specific variables that can discriminate effectively the Crohn's Disease and Ulcerative Colitis groups.

CONCLUSIONS

We identified significant variables that discriminate the two groups, satisfying the multiplicity problem, in fact we can affirm that Smoking habit, Immunosuppressive therapy, Surgery, Biological Drug, Diabetes, Adverse Events, Hospitalization, Gender and Duration of Immunosoppressive Therapy are the effectively significant variables.

Smoking Interacts With CHRNA5, a Nicotinic Acetylcholine Receptor Subunit Gene, to Influence the Risk of IBD-Related Surgery

BACKGROUND

Inflammatory bowel disease (IBD) is a chronic luminal disease with genetic and environmental factors affecting phenotype. This study evaluated the relationship between CHRNA5, a nicotinic receptor subunit gene, and smoking in predicting IBD-related surgery as well as the relationship between CHRNA5 and nicotine dependence.

METHODS

Participants completed a smoking questionnaire and were genotyped for CHRNA5 rs16969968. Demographic and clinical data were obtained from medical records. Wilcoxon, ANOVA, Chi square, and Fisher's exact tests were used for comparisons. Logistic regression was used to evaluate the effect of clinical and genetic predictors on surgery, stratified by disease subtype given paradoxical effects of smoking. Kaplan-Meier curves were used to examine the effect of smoking and genotype on time to surgery. (Significance: P < 0.05 for main effects; P < 0.2 for interaction terms).

RESULTS

400 (65.8%) patients had Crohn's disease (CD) and 208 (34.2%) had ulcerative colitis (UC). 298 (49%) underwent an IBD-related surgery. There was a trend towards significance between rs16969968 and smoking behavior (smoking status [P = 0.05], nicotine dependence [AA > AG > GG; P = 0.08]). Smoking and genotype were not independently associated with surgery in UC or CD. However, interaction between rs16969968 and smoking in predicting surgery was observed for both UC (OR = 2.72; P = 0.05) and CD (OR = 2.88; P = 0.1). CHRNA5 genotype, but not smoking, predicted time to surgery in patients with UC (P = 0.007) but not in patients with CD. The interaction between smoking and genotype was not significantly associated with time to surgery in UC or CD.

CONCLUSIONS

The CHRNA5 rs16969968 A variant interacts with smoking to influence IBD-related surgery. 10.1093/ibd/izx094_video1izx094.video15775248538001.

The impact of inflammatory bowel disease on oral health

Inflammatory bowel disease (IBD) mainly comprises of two separate inflammatory conditions: Crohn's disease (CD) and ulcerative colitis (UC). The aetiology of these conditions is still being explored with current evidence pointing towards a combination of environmental and genetic components. However, the pathophysiology is understood as a cytokine driven inflammatory response. There is significant association between IBD and dental conditions such as dental caries, other infections and periodontitis. Anti-inflammatory medications such as 5 aminosalicylic acid (5ASA), steroids and biological therapies are the treatment of choice for these chronic conditions, dependent on aetiology. Therefore, this article aims to educate dentists regarding possible implications IBD and its treatment can have for clinical practice and future research.

Gastrointestinal diseases and their oro-dental manifestations: Part 2: Ulcerative colitis

Ulcerative colitis is a rather common inflammatory bowel disease, especially in the industrialised world. A limited number of studies have reported the prevalence of oral signs and symptoms in these patients, and widely varying prevalence rates have been reported ranging from 2 to 34%. Pyostomatitis vegetans is the most pathognomonic oral sign but also other abnormalities as oral ulcerations, caries and periodontitis are more often seen in patients with ulcerative colitis. In this review we describe the oral manifestations of ulcerative colitis and their potential dental implications.

Ethnicity Influences Phenotype and Outcomes in Inflammatory Bowel Disease: A Systematic Review and Meta-analysis of Population-based Studies

BACKGROUND & AIMS

Inflammatory bowel diseases (IBDs) (Crohn's disease [CD], ulcerative colitis) are global diseases. Similarities and differences in disease presentation and outcomes across different geographic regions and ethnic groups have not been compared previously.

METHODS

We performed a systematic review and meta-analysis of population-based cohort studies examining the phenotype and outcome of IBD across ethnic groups categorized as Whites, Blacks, Hispanics, and Asians. Further stratification was performed by migration status (native or immigrant). Pooled proportions of disease location, behavior, medication, and surgery use were calculated by using a random-effects model and compared statistically.

RESULTS

Our final analysis included 198 unique studies reporting outcomes on 525,425 IBD patients (Caucasian, 65%; Asian, 30%; Hispanic, 2%; and Black, 1%). CD in Asians but not other ethnicities demonstrated a strong male predominance. Family history of IBD was infrequent in Asian patients. Both Black and Asian CD patients demonstrated perianal involvement more frequently. Surgery for both CD and UC was less common in Asians than Caucasians. Compared with native residents, a family history of IBD was reported more often among immigrant IBD patients, but no significant differences were noted in phenotype.

CONCLUSIONS

We demonstrate significant variation in the demographic distribution, familial predisposition, phenotype, and outcomes of IBD between Caucasians, Blacks, Hispanics, and Asians. There is need for further study to understand the biology behind this variation.

Fibre intake and the development of inflammatory bowel disease: A European prospective multi-centre cohort study (EPIC-IBD)

BACKGROUND AND AIMS

Population-based prospective cohort studies investigating fibre intake and development of inflammatory bowel disease are lacking. Our aim was to investigate the association between fibre intake and the development of Crohn's disease [CD] and ulcerative colitis [UC] in a large European population.

METHODS

In total, 401326 participants, aged 20-80 years, were recruited in eight countries in Europe between 1991 and 1998. At baseline, fibre intake [total fibres, fibres from fruit, vegetables and cereals] was recorded using food frequency questionnaires. The cohort was monitored for the development of inflammatory bowel disease. Each case was matched with four controls and odds ratios [ORs] for the exposures were calculated using conditional logistic regression. Sensitivity analyses according to smoking status were computed.

RESULTS

In total, 104 and 221 participants developed incident CD and UC, respectively. For both CD and UC, there were no statistically significant associations with either quartiles, or trends across quartiles, for total fibre or any of the individual sources. The associations were not affected by adjusting for smoking and energy intake. Stratification according to smoking status showed null findings apart from an inverse association with cereal fibre and CD in non-smokers [Quartile 4 vs 1 OR = 0.12, 95% confidence interval = 0.02-0.75, p = 0.023, OR trend across quartiles = 0.50, 95% confidence interval = 0.29-0.86, p = 0.017].

CONCLUSION

The results do not support the hypothesis that dietary fibre is involved in the aetiology of UC, although future work should investigate whether there may be a protective effect of specific types of fibre according to smoking status in CD.

Correlation of Severity of Functional Gastrointestinal Disease Symptoms with that of Asthma and Chronic Obstructive Pulmonary Disease: A Multicenter Study

Introduction

There is a growing clinical awareness about the influence of gut-lung axis on lung injury and coexisting manifestations of disease processes in both the intestine and lungs. Patients of chronic lung diseases such as chronic obstructive pulmonary disease (COPD) and asthma very often present with coexistent gut symptoms. In the present study, we have tried to establish the correlation of severity of pulmonary pathology of COPD and asthma patients with functional gastrointestinal (GI) symptoms of the patients.

Materials and Methods

This is a prospective, questionnaire-based study comprising patients with asthma and COPD. After following strict inclusion and exclusion criteria, a total of 200 patients (100 patients of bronchial asthma and 100 patients of COPD) were included in the study. Functional GI symptom questionnaire [Annexure 1-Bowel Disease Questionnaire] is based on ROME III diagnostic criteria. On the basis of GOLD (Global Initiative for Obstructive Lung Disease) guidelines, COPD patients were divided into 4 categories (mild - GOLD 1, moderate - GOLD2, severe - GOLD3 and very severe - GOLD4). Asthma patients were divided into three categories (well controlled, partly controlled, uncontrolled) on the basis of GINA (Global Initiative for Asthma) guidelines.

Results

Highest percentage of patients with maximum GI symptoms was found in "GOLD-4" group among COPD patients and "uncontrolled" group among asthma patients. Highest percentage of patients with least GI symptoms was found in "GOLD-1" group among COPD patients and "well controlled" group among asthma patients.

Conclusion

We can conclude from our study that the phenomenon of gut-lung axis not only exists but also the severity of symptoms of one system (gut) carries a high degree of concordance with severity of other (lung).

Cigarette Smoking Triggers Colitis by IFN-γ+ CD4+ T Cells

The increased incidence of Crohn’s disease in smokers has been recently reported, suggesting a strong association of cigarette smoke (CS) with colitis. However, the mechanism of the action of CS on colitis has not yet been explored. Here, we demonstrate that CS exposure is sufficient to induce colitis in mice. Interestingly, the colitis is mainly mediated by Th1, but not Th17, responses. CD4⁺ T-cell depletion or T-bet/IFN-γ deficiency protects against the development of colitis induced by CS. Additionally, IFN-γ-producing CD4⁺ T cells play a substantial role in CS-induced colitis. The adoptive transfer (AT) of effector T cells from CS-exposed WT mice into colitis-prone mice caused these mice to develop colitis, while the AT of effector T cells from IFN-γ knock-out mice did not. These findings have implications for broadening our understanding of CS-induced pathology and for the development of novel therapeutic strategies to treat Crohn’s disease.

Significance of non-alcoholic fatty liver disease in Crohn's disease: A retrospective cohort study

AIM

The prevalence of non-alcoholic fatty liver disease (NAFLD) and Crohn's disease (CD) is increasing. The aim of our study was to evaluate the prevalence of NAFLD in patients with CD, as well as to investigate the effect of NAFLD on the disease course of CD.

METHODS

Our retrospective cohort study included 303 patients who underwent abdominal ultrasound for CD and NAFLD diagnosis at our center between November 2008 and October 2014. Serum C-reactive protein (CRP) level and rate of remission, defined by a score <150 on the Crohn's Disease Activity Index, were compared between CD patients with and without NAFLD, using multivariate logistic regression. The effect of NAFLD on the surgery-free interval was evaluated using Cox proportional hazards models, adjusted for potential demographic confounders.

RESULTS

Non-alcoholic fatty liver disease was diagnosed in 66 (21.8%) patients in our study cohort and was associated with lower CRP levels (0.58 vs. 2.18 mg/dL, P < 0.0001) and a higher rate of remission (75.9% vs. 53.7%, P = 0.0024). Non-alcoholic fatty liver disease was identified as an independent predictor of a negative CRP level (<0.3 mg/dL; odds ratio, 1.85; 95% confidence interval, 1.03-3.37) and higher rate of remission (odds ratio, 2.57; 95% confidence interval, 1.21-5.80). Non-alcoholic fatty liver disease was associated with longer surgery-free interval (log-rank test, P = 0.0035), with NAFLD identified as a positive predictor of surgery-free interval (P = 0.0014).

CONCLUSIONS

Non-alcoholic fatty liver disease may offer a protective effect in patients with CD and could be used as a prognostic marker in patients with CD.

Genetic Factors Interact With Tobacco Smoke to Modify Risk for Inflammatory Bowel Disease in Humans and Mice

BACKGROUND & AIMS

The role of tobacco smoke in the etiology of inflammatory bowel disease (IBD) is unclear. We investigated interactions between genes and smoking (gene-smoking interactions) that affect risk for Crohn's disease (CD) and ulcerative colitis (UC) in a case-only study of patients and in mouse models of IBD.

METHODS

We used 55 Immunochip-wide datasets that included 19,735 IBD cases (10,856 CD cases and 8879 UC cases) of known smoking status. We performed 3 meta-analyses each for CD, UC, and IBD (CD and UC combined), comparing data for never vs ever smokers, never vs current smokers, and never vs former smokers. We studied the effects of exposure to cigarette smoke in Il10^-/- and Nod2^-/- mice, as well as in Balb/c mice without disruption of these genes (wild-type mice). Mice were exposed to the smoke of 5 cigarettes per day, 5 days a week, for 8 weeks, in a ventilated smoking chamber, or ambient air (controls). Intestines were collected and analyzed histologically and by reverse transcription polymerase chain reaction.

RESULTS

We identified 64 single nucleotide polymorphisms (SNPs) for which the association between the SNP and IBD were modified by smoking behavior (meta-analysis Wald test P < 5.0 × 10^-5; heterogeneity Cochrane Q test P > .05). Twenty of these variants were located within the HLA region at 6p21. Analysis of classical HLA alleles (imputed from SNP genotypes) revealed an interaction with smoking. We replicated the interaction of a variant in NOD2 with current smoking in relation to the risk for CD (frameshift variant fs1007insC; rs5743293). We identified 2 variants in the same genomic region (rs2270368 and rs17221417) that interact with smoking in relation to CD risk. Approximately 45% of the SNPs that interact with smoking were in close vicinity (≤1 Mb) to SNPs previously associated with IBD; many were located near or within genes that regulate mucosal barrier function and immune tolerance. Smoking modified the disease risk of some variants in opposite directions for CD vs UC. Exposure of Interleukin 10 (il10)-deficient mice to cigarette smoke accelerated development of colitis and increased expression of interferon gamma in the small intestine compared to wild-type mice exposed to smoke. NOD2-deficient mice exposed to cigarette smoke developed ileitis, characterized by increased expression of interferon gamma, compared to wild-type mice exposed to smoke.

CONCLUSIONS

In an analysis of 55 Immunochip-wide datasets, we identified 64 SNPs whose association with risk for IBD is modified by tobacco smoking. Gene-smoking interactions were confirmed in mice with disruption of Il10 and Nod2-variants of these genes have been associated with risk for IBD. Our findings from mice and humans revealed that the effects of smoking on risk for IBD depend on genetic variants.

Inflammatory bowel disease in Bahrain: single-center experience

Purpose

The number of newly diagnosed inflammatory bowel disease (IBD) cases such as ulcerative colitis (UC), Crohn’s disease (CD), and indeterminate colitis (IC) is rapidly increasing in Gulf countries and Saudi Arabia. The aim of this study was to investigate the incidence and prevalence of IBD in patients who have attended the Salmaniya Medical Complex, Bahrain, between the years 1984 and 2014.

Patients and methods

All patients who had attended the Salmaniya Medical Complex, Bahrain, and had been diagnosed with UC, CD, or IC, between the years 1984 and 2014, were included in the analysis. Data collected were: patient demographics, symptoms, clinical signs, complications, surgical interventions, extent of disease, endoscopic findings, histopathology, and lab measurements.

Results

A total of 187 cases were included; 61 had CD, 123 had UC, and a further 3 cases presented with IC. A clear increase in the incidence and prevalence of IBD can be seen in this cohort. The prevalence of IBD was calculated to be 26.25/10⁵ cases. The average number of IBD cases increased from 3 cases (average for the years 1984–2001) to 12 cases (average for the years 2002–2014). A number of factors correlate positively or negatively with CD and UC. In the current study, a link between gastrointestinal complications in CD cases and the use of steroids as a treatment was noted (p-value −0.02). Age also had a significant influence on the need for surgery in CD cases (p-value −0.04), and a family history of UC was statistically linked to surgical intervention (p-value −0.05).

Conclusions

IBD can no longer be considered a rare disease in Bahrain. The incidence of both UC and CD is steadily increasing. There is a need for increasing awareness of the Bahraini public to IBD in order for proper medical care to be given.

Cigarette smoking and the risk of primary Sjögren's syndrome: a nested case control study

BACKGROUND

Smoking is reported to affect the risk of a number of chronic disorders, including rheumatic diseases. Previous cross-sectional studies have shown a lower frequency of smoking in patients with primary Sjögren's syndrome (pSS). The aim of this study was to investigate the impact of smoking and socioeconomic status on the risk of subsequent diagnosis of pSS in a nested case-control study.

METHOD

Participants in two large population-based health surveys who were later diagnosed with pSS were identified through linkage with the Malmö Sjögren's Syndrome Register. Matched controls were obtained from the health surveys.

RESULTS

Sixty-three patients with pSS with pre-diagnostic data from the health surveys were identified. Current smoking was associated with a significantly lower risk of later being diagnosed with pSS (odds ratio (OR) 0.3; 95% CI 0.1-0.6). Furthermore, former smoking was associated with an increased risk of subsequent pSS diagnosis (OR 4.0; 95% CI 1.8-8.8) compared to never smoking. Similar results were found in a sub-analysis of patients with reported symptom onset after inclusion in the health surveys. Socioeconomic status and levels of formal education had no significant impact on the risk of later being diagnosed with pSS.

CONCLUSION

In this nested case-control study, current smoking was associated with a reduced risk of subsequent diagnosis of pSS. In addition, former smoking was associated with an increased risk. Whether this reflects a biological effect of cigarette smoking or other mechanisms should be further investigated in future studies.

Sodium chloride-enriched Diet Enhanced Inflammatory Cytokine Production and Exacerbated Experimental Colitis in Mice

BACKGROUND AND AIM

Environmental factors are supposed to play a decisive role in the pathogenesis of inflammatory bowel diseases [IBDs]. Increased dietary salt intake has been linked with the development of autoimmune diseases, but the impact of a salt-enriched diet on the course of IBD remains unknown. In this study, we examined whether high salt intake alters mucosal cytokine production and exacerbates colitis.

METHODS

Normal intestinal lamina propria mononuclear cells [LPMCs] were activated with anti-CD3/CD28 in the presence or absence of increasing concentrations of sodium chloride [NaCl] and/or SB202190, a specific inhibitor of p38/MAP Kinase. For in vivo experiments, a high dose of NaCl was administered to mice 15 days before induction of trinitrobenzene-sulfonic acid [TNBS]-colitis or dextran sulfate sodium [DSS]-colitis. In parallel, mice were given SB202190 before induction of TNBS-colitis. Transcription factors and effector cytokines were evaluated by flow-cytometry and real-time PCR.

RESULTS

IL-17A, IL-23R, TNF-α, and Ror-γT were significantly increased in human LPMCs following NaCl exposure, while there was no significant change in IFN-γ, T-bet or Foxp3. Pharmacologic inhibition of p38/MAPK abrogated the NaCl-inducing effect on LPMC-derived cytokines. Mice receiving the high-salt diet developed a more severe colitis than control mice, and this effect was preventable by SB202190.

CONCLUSIONS

Our data indicated that exposure of intestinal mononuclear cells to a high-NaCl diet enhanced effector cytokine production and contributed to the exacerbation of experimental colitis in mice.

Orofacial Crohn’s disease: A case report

Background: Crohn’s disease (CD) and ulcerative colitis (UC) are the two major relapsing conditions of inflammatory bowel diseases. Case Report: A case of Crohn’s disease with orofacial manifestations in a 10 year old girl is described. She had suffered from fever, dysphagia, arthralgia, painful recurrent ulcers of the oral mucosa and swelling of the lower lip lasting over 6 weeks. Clinical examination and the punch biopsy from the buccal mucosa revealed major recurrent aphthous ulcerations. A partial regression and significant relief of lesions were achieved two weeks after the treatment, but the patient suffered from abdominal pain, irregular bowel movements, arthritis, multiple hyperplastic and swollen mucosal folds, after 3 months. The patient was referred to a pediatric gastroenterologist. Esophagogastroduodenoscopy showed pyloric ulcer formation. Abdominal ultrasound showed increased thickening of the ileal wall with multiple enlarged lympadenopathies in the periileal region. Colonoscopy images showed deep ulcers with surrounding erythema. The histopathological examination of biopsies from the terminal ileum and the colon showed basal plasmacytosis, minimal crypt distortions and aphthous ulcerations. The diagnosis of Orofacial Crohn’s disease was made. Exclusive enteral nutrition for 8 weeks, followed by azathiopurine treatment was started with an excellent clinical response on abdominal and oral symptoms. Conclusion: Diagnosis of the disease by dentists and other clinicians through the evaluation of oral clinical findings is very rare. Mucocutaneous and granulomatous lesions of the oral cavity should alert the clinician to pursue an underlying systemic cause. Early communication with a gastroenterologist can help early diagnosis of Crohn’s disease for better patient management and prognosis.

Inflammatory bowel disease and airway diseases

Airway diseases are the most commonly described lung manifestations of inflammatory bowel disease (IBD). However, the similarities in disease pathogenesis and the sharing of important environmental risk factors and genetic susceptibility suggest that there is a complex interplay between IBD and airway diseases. Recent evidence of IBD occurrence among patients with airway diseases and the higher than estimated prevalence of subclinical airway injuries among IBD patients support the hypothesis of a two-way association. Future research efforts should be directed toward further exploration of this association, as airway diseases are highly prevalent conditions with a substantial public health impact.

Pathogenic role of the gut microbiota in gastrointestinal diseases

The gastrointestinal (GI) tract is colonized by a dense community of commensal microorganisms referred to as the gut microbiota. The gut microbiota and the host have co-evolved, and they engage in a myriad of immunogenic and metabolic interactions. The gut microbiota contributes to the maintenance of host health. However, when healthy microbial structure is perturbed, a condition termed dysbiosis, the altered gut microbiota can trigger the development of various GI diseases including inflammatory bowel disease, colon cancer, celiac disease, and irritable bowel syndrome. There is a growing body of evidence suggesting that multiple intrinsic and extrinsic factors, such as genetic variations, diet, stress, and medication, can dramatically affect the balance of the gut microbiota. Therefore, these factors regulate the development and progression of GI diseases by inducing dysbiosis. Herein, we will review the recent advances in the field, focusing on the mechanisms through which intrinsic and extrinsic factors induce dysbiosis and the role a dysbiotic microbiota plays in the pathogenesis of GI diseases.

Influence of environmental factors in the development of inflammatory bowel diseases

Idiopathic inflammatory bowel diseases (IBD), Crohn’s disease (CD) and ulcerative colitis (UC), are multifactorial diseases that are manifested after disruption of a genetic predisposed individual and its intestinal microflora through an environmental stimulus. Urbanization and industrialization are associated with IBD. Epidemiological data, clinical observations and family/immigrants studies indicate the significance of environmental influence in the development of IBD. Some environmental factors have a different effect on the subtypes of IBD. Smoking and appendectomy is negatively associated with UC, but they are aggravating factors for CD. A westernized high fat diet, full of refined carbohydrates is strongly associated with the development of IBD, contrary to a high in fruit, vegetables and polyunsaturated fatty acid-3 diet that is protective against these diseases. High intake of nonsteroidal antiinflammatory drug and oral contraceptive pills as well as the inadequacy of vitamin D leads to an increased risk for IBD and a more malignant course of disease. Moreover, other factors such as air pollution, psychological factors, sleep disturbances and exercise influence the development and the course of IBD. Epigenetic mechanism like DNA methylation, histone modification and altered expression of miRNAS could explain the connection between genes and environmental factors in triggering the development of IBD.

Nicotine Inhibits Clostridium difficile Toxin A-Induced Colitis but Not Ileitis in Rats

Nicotine is protective in ulcerative colitis but not Crohn's disease of the small intestine, but little is known about the effects of nicotine on Clostridium difficile toxin A-induced enteritis. Isolated ileal or colonic segments in anesthetized rats were pretreated with nicotine bitartrate or other pharmacological agents before intraluminal injection of toxin A. After 3 hours, the treated segments were removed and inflammation was assessed. Nicotine biphasically inhibited toxin A colitis but not ileitis. Pretreatment with the nicotinic receptor antagonist, hexamethonium, blocked the effects of nicotine. Pretreating the colonic segments with hexamethonium before toxin A administration resulted in more inflammation than seen with toxin A alone, suggesting that a tonic nicotinic anti-inflammatory condition exists in the colon. Nicotine also inhibited toxin A-induced increased colonic concentrations of the TRPV1 (transient receptor potential vanilloid subtype 1) agonist, leukotriene B4 (LTB4), and release of the proinflammatory neuropeptide, substance P. Pretreatment with nicotine did not protect against direct TRPV1-mediated colitis caused by intraluminal capsaicin. Nicotinic cholinergic receptors tonically protect the colon against inflammation and nicotine inhibits toxin A colitis but not toxin A ileitis in rats in part by inhibition of toxin A-induced activation of TRPV1 by endogenous TRPV1 agonists such as LTB4.

Smoking behaviour and knowledge of the health effects of smoking in patients with inflammatory bowel disease

BACKGROUND

The detrimental effect of smoking on development and progression of Crohn's disease (CD) is generally accepted.

AIM

To evaluate the awareness of smoking risks in a Belgian inflammatory bowel disease (IBD) population.

METHODS

In the out-patient clinic of a tertiary referral centre, 625 consecutive patients with CD, 238 patients with ulcerative colitis (UC) and 289 non-IBD controls, filled out a simple questionnaire. This questionnaire included data on smoking behaviour and awareness of smoking-related health effects, including effects on IBD.

RESULTS

At diagnosis, more CD patients were active smokers compared to UC (40% vs. 17%, P < 0.001). Remarkably, smoking cessation rates after diagnosis were similar for CD and UC (both 56%, P = 0.997). The great majority recognised a detrimental influence of smoking on general health (98-99%), lung cancer (95-97%), myocardial infarction (89-92%) and stroke (78-87%). Although CD patients more frequently acknowledged risks of smoking on their disease, only 37% were aware of a link with CD development, 30% of increased surgical rates and 27% of increased post-operative CD recurrence. Active smokers more frequently denied an increased risk of surgery and higher post-operative CD recurrence. Intriguingly, within the active smokers with CD, those not willing to quit smoking most often denied a potential bad influence of smoking. Taking into account disease duration, previous surgery, education level, working status and nicotine dependence, we were unable to define specific subgroups of patients requiring extra education.

CONCLUSION

Although patients with Crohn's disease were better informed on the detrimental effects of smoking, the awareness rate was still low.

The Neuromodulation of the Intestinal Immune System and Its Relevance in Inflammatory Bowel Disease

One of the main tasks of the immune system is to discriminate and appropriately react to “danger” or “non-danger” signals. This is crucial in the gastrointestinal tract, where the immune system is confronted with a myriad of food antigens and symbiotic microflora that are in constant contact with the mucosa, in addition to any potential pathogens. This large number of antigens and commensal microflora, which are essential for providing vital nutrients, must be tolerated by the intestinal immune system to prevent aberrant inflammation. Hence, the balance between immune activation versus tolerance should be tightly regulated to maintain intestinal homeostasis and to prevent immune activation indiscriminately against all luminal antigens. Loss of this delicate equilibrium can lead to chronic activation of the intestinal immune response resulting in intestinal disorders, such as inflammatory bowel diseases (IBD). In order to maintain homeostasis, the immune system has evolved diverse regulatory strategies including additional non-immunological actors able to control the immune response. Accumulating evidence strongly indicates a bidirectional link between the two systems in which the brain modulates the immune response via the detection of circulating cytokines and via direct afferent input from sensory fibers and from enteric neurons. In the current review, we will highlight the most recent findings regarding the cross-talk between the nervous system and the mucosal immune system and will discuss the potential use of these neuronal circuits and neuromediators as novel therapeutic tools to reestablish immune tolerance and treat intestinal chronic inflammation.

High Rates of Smoking Especially in Female Crohn's Disease Patients and Low Use of Supportive Measures to Achieve Smoking Cessation--Data from the Swiss IBD Cohort Study

BACKGROUND AND AIMS

Smoking is a crucial environmental factor in inflammatory bowel disease [IBD]. However, knowledge on patient characteristics associated with smoking, time trends of smoking rates, gender differences and supportive measures to cease smoking provided by physicians is scarce. We aimed to address these questions in Swiss IBD patients.

METHODS

Prospectively obtained data from patients participating in the Swiss IBD Cohort Study was analysed and compared with the general Swiss population [GSP] matched by age, sex and year.

RESULTS

Among a total of 1770 IBD patients analysed [49.1% male], 29% are current smokers. More than twice as many patients with Crohn's disease [CD] are active smokers compared with ulcerative colitis [UC] [UC, 39.6% vs CD 15.3%, p < 0.001]. In striking contrast to the GSP, significantly more women than men with CD smoke [42.8% vs 35.8%, p = 0.025], with also an overall significantly increased smoking rate compared with the GSP in women but not men. The vast majority of smoking IBD patients [90.5%] claim to never have received any support to achieve smoking cessation, significantly more in UC compared with CD. We identify a significantly negative association of smoking and primary sclerosing cholangitis, indicative of a protective effect. Psychological distress in CD is significantly higher in smokers compared with non-smokers, but does not differ in UC.

CONCLUSIONS

Despite well-established detrimental effects, smoking rates in CD are alarmingly high with persistent and stagnating elevations compared with the GSP, especially in female patients. Importantly, there appears to be an unacceptable underuse of supportive measures to achieve smoking cessation.

Interleukin-18 genetic polymorphisms contribute differentially to the susceptibility to Crohn’s disease

AIM: To investigate the correlation between interleukin-18 (IL-18) gene polymorphisms and the risk of developing Crohn’s disease (CD).

METHODS: The PubMed, CISCOM, CINAHL, Web of Science, EBSCO, Cochrane Library, MEDLINE, EMBASE and CBM databases were searched without any language restrictions using combinations of keywords relating to CD and IL-18 for relevant articles published before November 1^st, 2013. Screening of the published studies retrieved from searches was based on our stringent inclusion and exclusion criteria and resulted in seven eligible studies for meta-analysis. A meta-analysis was conducted using a random-effects model with STATA 12.0 software. Crude odds ratios (ORs) with 95% confidence intervals (95%CI) were calculated.

RESULTS: Seven case-control studies, with a total of 1930 CD cases and 1930 healthy subjects, met our inclusion criteria. The results of our meta-analysis indicated that the IL-18 rs1946518 A>C and rs187238 G>C polymorphisms may correlate with an increased risk of CD under five genetic models (all P < 0.05). Furthermore, we observed positive associations between the IL-18 rs360718 A>C polymorphism and CD risk under three genetic models (C allele vs A allele: OR = 2.03, 95%CI: 1.20-3.43, P = 0.008; CC vs AA+AC: OR = 2.39, 95%CI: 1.2-4.43, P = 0.006; CC vs AC: OR = 2.31, 95%CI: 1.22-4.38, P = 0.010). However, such associations were not found for the IL-18 rs917997 C>T, codon 35 A>C and rs1946519 G>T polymorphisms (all P > 0.05). A subgroup analysis was conducted to investigate the effect of ethnicity on an individual’s susceptibility to CD. Our results revealed positive correlations between IL-18 genetic polymorphisms and an increased risk of CD among Asians and Africans (all P < 0.05), but not among Caucasians (all P > 0.05).

CONCLUSION: This meta-analysis indicated that the IL-18 rs1946518 A>C, rs187238 G>C and rs360718 A>C polymorphisms may contribute to susceptibility to CD, especially among Asians and Africans. These polymorphisms are known to reduce IL-18 mRNA and protein levels.