Effects of light smoking consumption on the clinical course of Crohn's disease

The Pathogenesis of Inflammatory Bowel Diseases

Inflammatory bowel diseases (IBDs) are relapsing, remitting inflammatory diseases of the intestinal tract. Familial aggregation and genome-wide association studies revealed susceptibility variants that point toward a combination of innate immune and adaptive immune dysregulation that in concert with environmental factors, such as our microbiome, can initiate and perpetuate inflammation. Innate immune perturbations include functional abnormalities in the intestinal barrier, endoplasmic reticulum stress, and abnormal recognition of microbes. Adaptive immune changes include dysregulation of cytokines, regulatory T cells, and leukocyte migration. IBD is linked with an abnormal wound-healing response leading to fibrosis. This article summarizes key pathogenic mechanisms in the pathogenesis of IBDs.

Effects of smoking on clinical treatment outcomes amongst patients with chronic inflammatory diseases initiating biologics: secondary analyses of the prospective BELIEVE cohort study

The prevalence and disease burden of chronic inflammatory diseases (CIDs) are predicted to rise. Patients are commonly treated with biological agents, but the individual treatment responses vary, warranting further research into optimizing treatment strategies. This study aimed to compare the clinical treatment responses in patients with CIDs initiating biologic therapy based on smoking status, a notorious risk factor in CIDs. In this multicentre cohort study including 233 patients with a diagnosis of Crohn's disease, ulcerative colitis, rheumatoid arthritis, axial spondyloarthritis, psoriatic arthritis or psoriasis initiating biologic therapy, we compared treatment response rates after 14 to 16 weeks and secondary outcomes between smokers and non-smokers. We evaluated the contrast between groups using logistic regression models: (i) a "crude" model, only adjusted for the CID type, and (ii) an adjusted model (including sex and age). Among the 205 patients eligible for this study, 53 (26%) were smokers. The treatment response rate among smokers (n = 23 [43%]) was lower compared to the non-smoking CID population (n = 92 [61%]), corresponding to a "crude" OR of 0.51 (95% CI: [0.26;1.01]) while adjusting for sex and age resulted in consistent findings: 0.51 [0.26;1.02]. The contrast was apparently most prominent among the 38 RA patients, with significantly lower treatment response rates for smokers in both the "crude" and adjusted models (adjusted OR 0.13, [0.02;0.81]). Despite a significant risk of residual confounding, patients with CIDs (rheumatoid arthritis in particular) should be informed that smoking probably lowers the odds of responding sufficiently to biological therapy. Registration: Clinical.Trials.gov NCT03173144.

Comparison of outcomes in small bowel surgery for Crohn's disease: a retrospective NSQIP review

INTRODUCTION

Despite advances in medical therapy, approximately 33% of Crohn's disease (CD) patients will need surgery within 5 years after initial diagnosis. Several surgical approaches to CD have been proposed including small bowel resection, strictureplasty, and combined surgery with resection plus strictureplasty. Here, we utilize the American College of Surgeons (ACS) national surgical quality registry (NSQIP) to perform a comprehensive analysis of 30-day outcomes between these three surgical approaches for CD.

METHODS

The authors queried the ACS-NSQIP database between 2015 and 2020 for all patients undergoing open or laparoscopic resection of small bowel or strictureplasty for CD using CPT and IC-CM 10. Outcomes of interest included length of stay, discharge disposition, wound complications, 30-day related readmission, and reoperation.

RESULTS

A total of 2578 patients were identified; 87% of patients underwent small bowel resection, 5% resection with strictureplasty, and 8% strictureplasty alone. Resection plus strictureplasty (combined surgery) was associated with the longest operative time (p = 0.002). Patients undergoing small bowel resection had the longest length of hospital stay (p = 0.030) and the highest incidence of superficial/deep wound infection (44%, p = 0.003) as well as the highest incidence of sepsis (3.5%, p = 0.03). Small bowel resection was found to be associated with higher odds of wound complication compared to combined surgery (OR 2.09, p = 0.024) and strictureplasty (1.9, p = 0.005).

CONCLUSION

Our study shows that various surgical approaches for CD are associated with comparable outcomes in 30-day related reoperation and readmission, or disposition following surgery between all three surgical approaches. However, small bowel resection displayed higher odds of developing post-operative wound complications.

Enabling tobacco treatment for gastroenterology patients via a novel low-burden point-of-care model

BACKGROUND & AIM

Smoking is a major risk factor for multiple gastrointestinal cancers, and adversely affects peptic ulcer disease, gastroesophageal reflux, pancreatitis and Crohn's disease. Despite key recommendations for diagnosing and treating tobacco use disorder in healthcare settings, the degree to which this is implemented in Gastroenterology (GI) clinics is unknown. We aimed to assess our providers' practices, identify barriers for implementing evidence-based smoking cessation treatments, and address these barriers by implementing a novel low-burden point of care Electronic health record-enabled evidence-based tobacco treatment (ELEVATE), in GI clinics.

METHODS

An online survey was distributed to clinic gastroenterologists. ELEVATE module training was implemented in 1/2021. Data were evaluated during pre (7/2020-12/2020) and post (1/2021-12/2021) implementation periods to evaluate the reach and effectiveness of ELEVATE. Generalized estimating equations (GEE) were used to generate rate ratios (RR) to evaluate the intervention.

RESULTS

91% (20/22) of GI physicians responded to our survey, and only 20% often assisted patients who smoke with counseling. Lack of a systematic program to offer help to patients was reported by 80% of providers as an extremely/very important barrier limiting their smoking cessation practices. The proportion of current patients who smoke receiving cessation treatment increased from pre-ELEVATE to post-ELEVATE (14.36-27.47%, RR = 1.90, 95% CI 1.60-2.26, p < .001). Post-ELEVATE, 14.4% (38/264) of patients with treatment quit smoking, compared to 7.9% (55/697) of patients without treatment (RR = 1.89, 95% CI 1.26-2.82, p = .0021).

CONCLUSION

Smoking practices are frequently assessed in GI clinics but barriers limiting cessation treatment exist. The use of a low burden point of care EHR enabled smoking cessation treatment module has led to a significant improvement in the treatment of smoking and subsequent cessation in our clinics. This study sheds light on an often under-recognized source of morbidity in GI patients and identifies an efficient, effective, and scalable strategy to combat tobacco use and improve clinical outcomes in our patients.

Assessing Progression of Biologic Therapies Based on Smoking Status in Patients With Crohn's Disease

BACKGROUND

Active smoking is a well-established risk factor for developing Crohn's disease (CD) and negatively impacts overall disease progression. Patients who start or continue smoking after CD diagnosis are at risk for poor outcomes, higher therapeutic requirements, and have higher rates of relapse. However, it remains unclear if the exposure to smoking leads to increased sequencing through treatment therapies, especially biologics.

METHODS

The Study of Prospective Adult Research Cohort with IBD (SPARC IBD) registry has been collecting patient-reported outcomes data in real-time, as well as laboratory, endoscopic, and pathologic samples from 17 tertiary referral centers since 2016. In this study, we conducted a retrospective review of the SPARC clinical registry collected between December 2016 and January 2021 from 1 participating site, the University of Maryland School of Medicine's Inflammatory Bowel Disease Program. A total of 619 patients were enrolled in the SPARC IBD database. Four hundred twenty-five patients with CD were included for initial review of completeness of data; of these, 144 patients were excluded due to missing data on smoking status and/or biologic treatment, resulting in a final cohort of 281 patients. We collected and analyzed baseline demographic and clinical characteristics. The final cohort was categorized into 3 exposure groups: current, former, and never smokers. Our outcome of interest was number biologics used, categorized into 3 groups: 0, 1, or ≥2 biologics.

RESULTS

One hundred seventy-two never smokers, 70 former smokers, and 39 current smokers were identified. Current, former, and never smokers had no statistically significant differences in number of biologics used (ie, biologic sequencing). However, statistically significant independent risk factors for increased sequencing of biologics were identified. These risk factors included female sex, ileocolonic disease location, younger age at diagnosis, and prolonged disease duration; none of these factors remained significant in adjusted analyses.

CONCLUSION

To date, this is the first study assessing the association of smoking and sequencing of biologics. Although current or former smokers were not found to sequence through more biologics when compared with never smokers, smoking is a well-established risk factor for poor health outcomes, and efforts should be made to counsel patients to quit. Further, additional research must be done to stratify risk to patients based on amount of tobacco exposure.

The Relationship Between Smoking Status, Carbon Monoxide Levels, Quality of Life, and Disease Features in Inflammatory Bowel Diseases

Objective: The aim of the study was to analyze the relationship between smoking status and exhaled carbon monoxide (E-CO) levels, quality of life, and disease characteristics in patients with inflammatory bowel disease. Methods: The demographic and disease characteristics and smoking status of 121 patients with inflammatory bowel disease who presented our hospital between 01.12.2020 and 01.03.2021 were investigated. After the first follow-up, the E-CO levels of these participants were measured every four consecutive weeks. The mean of these E-CO readings was accepted as the main E-CO value. After one month after their first application SF-36 Quality of Life Scale was applied. The relationship between these variables was investigated. Results: The mean age of the participants was 42.06±14.9 years, and 36.3% were active smokers. While patients with Crohn’s disease (CD) exhibited a higher smoking rate, smokers with ulcerative colitis (UC) registered significantly higher mean CO ppm readings (p

Trends in the environmental risks associated with earlier onset in multiple sclerosis

BACKGROUND

Several environmental and lifestyle factors relating to sunlight/vitamin D, body mass index (BMI), and smoking are associated with the risk of developing multiple sclerosis (MS). However, their relation to disease progression, particularly age at symptomatic onset, remains inconsistent, which may be the result of significant changes in human-environment interactions over the last century. This study investigates historical trends in the association between common MS environmental risk factors and age at disease onset.

METHODS

Using a narrative approach, we evaluated the current literature for published studies assessing the association between vitamin-D, BMI, and tobacco smoking exposures with the risk of early/pediatric-onset MS and direct correlations with age at MS onset using MEDLINE, EMBASE, and Web of Science. Measures were plotted by the average calendar year of disease onset for each cohort to examine trends over time. In total, 25, 9, and 11 articles were identified for vitamin D, BMI, and smoking-related exposures, respectively.

RESULTS

Higher sun exposure habits and residential solar radiation were associated with older age at onset. On the contrary, two studies observed a negative correlation between age at onset and serum 25-hydroxyvitamin D (25(OH)D) levels. Higher adolescent BMI was generally associated with younger age at onset, although genetic susceptibility for childhood obesity was not significantly associated. Tobacco smoking was associated with later disease onset, despite being a risk factor for MS. Association with age at onset was inflated for more recent studies relating to smoking, while often weaker for serum vitamin D and BMI.

CONCLUSION

Current findings indicate a likely association between age at onset and environmental risk factors, such as sun exposure, adolescent BMI, and tobacco smoking, in certain populations. However, findings are often inconsistent and assessment of the relationships and potential changes over time require further investigation.

Novel Models of Crohn's Disease Pathogenesis Associated with the Occurrence of Mitochondrial Dysfunction in Intestinal Cells

Crohn’s disease remains one of the challenging problems of modern medicine, and the development of new and effective and safer treatments against it is a dynamic field of research. To make such developments possible, it is important to understand the pathologic processes underlying the onset and progression of Crohn’s disease at the molecular and cellular levels. During the recent years, the involvement of mitochondrial dysfunction and associated chronic inflammation in these processes became evident. In this review, we discuss the published works on pathogenetic models of Crohn’s disease. These models make studying the role of mitochondrial dysfunction in the disease pathogenesis possible and advances the development of novel therapies.

Altered Skin and Gut Microbiome in Hidradenitis Suppurativa

Hidradenitis suppurativa (HS) is a chronic inflammatory skin disease characterized by the formation of nodules, abscesses, and fistula at intertriginous sites. The skin-gut axis is an area of emerging research in inflammatory skin disease and is a potential contributory factor to the pathogenesis of HS. 59 patients with HS provided fecal samples, nasal and skin swabs of affected sites for analysis. 30 healthy controls provided fecal samples and 20 healthy controls provided nasal and skin swabs. We performed bacterial 16S rRNA gene amplicon sequencing on total DNA derived from the samples. Microbiome alpha diversity was significantly lower in the fecal, skin and nasal samples of individuals with HS which may be secondary to disease biology or related to antibiotic usage. Ruminococcus gnavus was more abundant in the fecal microbiome of individuals with HS, which is also reported in Crohn's disease (CD), suggesting comorbidity due to shared gut microbiota alterations. Finegoldia magna was over-abundant in HS skin samples relative to healthy controls. It is possible local inflammation is driven by F. magna through promoting the formation of neutrophil extracellular traps (NET). These alterations in both the gut and skin microbiome in HS warrant further exploration, and therapeutic strategies including fecal microbiota transplant (FMT) or bacteriotherapy could be of benefit.

Treatments of inflammatory bowel disease toward personalized medicine

Inflammatory bowel disease (IBD), including ulcerative colitis (UC) and Crohn's disease (CD), is a chronic inflammatory disease characterized by intestinal inflammation and epithelial injury. For the treatment of IBD, 5-aminosalicylic acids, corticosteroids, immunomodulators, and biologic agents targeting tumor necrosis factor (TNF)-α, α4β7-integrin, and interleukin (IL)-12/23 have been widely used. Especially, anti-TNF-α antibodies are the first biologic agents that presently remain at the forefront. However, 10-30% of patients resist biologic agents, including anti-TNF-α agents (primary non-responder; PNR), and 20-50% of primary responders develop treatment resistance within one year (secondary loss of response; SLR). Nonetheless, the etiologies of PNR and SLR are not clearly understood, and predictors of response to biologic agents are also not defined yet. Numerous studies are being performed to discover prediction markers of the response to biologic agents, and this review will introduce currently available therapeutic options for IBD, biologics under investigation, and recent studies exploring various predictive factors related to PNR and SLR.

MR-enterography in Crohn's disease: what MRE mural parameters are associated to one-year therapeutic management outcome?

OBJECTIVE

To investigate the association of mural parameters of MR-enterography (MRE) with one-year therapeutic management of Crohn's disease (CD) patients.

METHODS

CD patients, undergone MRE with diffusion-weighted imaging (DWI) and apparent diffusion coefficient (ADC) maps between January 2017 and June 2018, were retrospectively enrolled. Extramural complications represented an exclusion criterion because of their potential influence on the intrinsic characteristic of the bowel wall. Two groups of patients were defined on the base of the therapeutic management adopted at 1-year follow-up: Medical-group and surgical-group. The following MRE parameters were evaluated: wall-thickening, longitudinal-extension, T2-fat-suppression-mural-signal, ulcers, mural-oedema, wall-enhancement-rate/pattern, DWI-scores, ADC-values, strictures.

RESULTS

70 CD patients were enrolled. 57/70 (81.4%) were included in Medical-group and 13/70 (18.6%) in Surgical-group. ADCmean and strictures resulted to be significantly (p < 0.01) different between the two groups. The ADCmean showed to be significantly associated to conservative management [p < 0.01; OR: 0.0003; 95% CI (0.00-0.13)], while the strictures to surgical management [p < 0.01; OR: 29.7; 95% CI (4.9-179.7)]. ROC curves for ADCmean showed that AUC was 0.717 [95% CI (0.607-0.810), p < 0.01] with an optimal cut-off value of 1.081 × 10^-3 mm² s^-1. A negative predictive value of 90.2% was observed associating ADCmean values > 1.081 × 10^-3 mm² s^-1 to conservative therapy. 13/17 (76%) strictures with an ADCmean > 1.081 × 10^-3 mm² s^-1 benefited of conservative therapy.

CONCLUSION

ADCmean values calculated on DWI-MRE may be associated to 1-year conservative medical therapy in patients with CD without extramural complications.

ADVANCES IN KNOWLEDGE

ADC maps may be proposed to select CD patients with a lower burden of mural active inflammatory cells and/or fibrosis benefiting of 1-year conservative treatment.

Personalizing Treatment in IBD: Hype or Reality in 2020? Can We Predict Response to Anti-TNF?

The advent of anti-TNF agents as the first approved targeted therapy in the treatment of inflammatory bowel disease (IBD) patients has made a major impact on our existing therapeutic algorithms. They have not only been approved for induction and maintenance treatment in IBD patients, but have also enabled us to define and achieve novel therapeutic outcomes, such as combination of clinical symptom control and endoscopic remission, as well as mucosal healing. Nevertheless, approximately one third of treated patients do not respond to initiated anti-TNF therapy and these treatments are associated with sometimes severe systemic side-effects. There is therefore the currently unmet clinical need do establish predictive markers of response to identify the subgroup of IBD patients, that have a heightened probability of response. There have so far been approaches from different fields of IBD research, to descry markers that would empower us to apply TNF-inhibitors in a more rational manner. These markers encompass findings from disease-related and clinical factors, pharmacokinetics, biochemical markers, blood and stool derived parameters, pharmacogenomics, microbial species, metabolic compounds, and mucosal factors. Furthermore, changes in the intestinal immune cell composition in response to therapeutic pressure of anti-TNF treatment have recently been implicated in the process of molecular resistance to these drugs. Insights into factors that determine resistance to anti-TNF therapy give reasonable hope, that a more targeted approach can then be utilized in these non-responders. Here, IL-23 could be identified as one of the key factors determining resistance to TNF-inhibitors. Growing insights into the molecular mechanism of action of TNF-inhibitors might also enable us to derive critical molecular markers that not only mediate the clinical effects of anti-TNF therapy, but which level of expression might also correlate with its therapeutic efficacy. In this narrative review, we present an overview of currently identified possible predictive markers for successful anti-TNF therapy and discuss identified molecular pathways that drive resistance to these substances. We will also point out the necessity and difficulty of developing and validating a diagnostic marker concerning clinically relevant outcome parameters, before they can finally enter daily clinical practice and enable a more personalized therapeutic approach.

Divergent Effect of Cigarette Smoke on Innate Immunity in Inflammatory Bowel Disease: A Nicotine-Infection Interaction

Cigarette smoke (CS) has adverse effects in patients with Crohn’s disease (CD), an inflammatory bowel disease (IBD) that has been associated with microbial infection, immuno-dysregulation, and mucosal dysfunction. However, CS seems to provide relief and protection to patients with another IBD known as ulcerative colitis (UC). These two subsets are featured as M1- and M2-mediated responses, respectively. Nicotine is the most active, addictive, and studied ingredient in CS. The mechanism of how nicotine and/or other CS ingredients induce pro-inflammatory or anti-inflammatory phenotypes in IBD patients remains under investigation. Our most recent in vitro nicotine study provided significant insights toward understanding the contradictory effects of nicotine on IBD patients, and it elucidated the mechanistic role of α7nAChR in modulation of macrophages in tobacco smokers. Shifting the beneficial effect of nicotine to a harmful outcome in CD patients was linked to a nicotine-microbe interaction that supports a microbial etiology in CD pathogenesis. Among the most debated pathogens in CD etiology is Mycobacterium avium subspecies paratuberculosis (MAP). Other studies associated nicotine with upregulation of miR-124 expression in macrophages, which led to anti-inflammatory response. This review discusses published work on the role of nicotine in modulation of the innate immune response and subsequent signaling in macrophages in IBD subsets.

Risk of acute arterial events associated with treatment of inflammatory bowel diseases: nationwide French cohort study

OBJECTIVE

Patients with IBD are at increased risk of acute arterial events. Antitumour necrosis factor (TNF) agents and thiopurines may, via their anti-inflammatory properties, lower the risk of acute arterial events. The aim of this study was to assess the impact of thiopurines and anti-TNFs on the risk of acute arterial events in patients with IBD.

DESIGN

Patients aged 18 years or older and affiliated to the French national health insurance with a diagnosis of IBD were followed up from 1 April 2010 until 31 December 2014. The risks of acute arterial events (including ischaemic heart disease, cerebrovascular disease and peripheral artery disease) were compared between thiopurines and anti-TNFs exposed and unexposed patients with marginal structural Cox proportional hazard models adjusting for baseline and time-varying demographics, medications, traditional cardiovascular risk factors, comorbidities and IBD disease activity.

RESULTS

Among 177 827 patients with IBD (96 111 (54%) women, mean age at cohort entry 46.2 years (SD 16.3), 90 205 (50.7%) with Crohn's disease (CD)), 4145 incident acute arterial events occurred (incidence rates: 5.4 per 1000 person-years). Compared with unexposed patients, exposure to anti-TNFs (HR 0.79, 95% CI 0.66 to 0.95), but not to thiopurines (HR 0.93, 95% CI 0.82 to 1.05), was associated with a decreased risk of acute arterial events. The magnitude in risk reduction was highest in men with CD exposed to anti-TNFs (HR 0.54, 95% CI 0.40 to 0.72).

CONCLUSION

Exposure to anti-TNFs is associated with a decreased risk of acute arterial events in patients with IBD, particularly in men with CD.

Exploring the Effects of Cigarette Smoking on Inflammatory Bowel Disease Using Mendelian Randomization

BACKGROUND

Previous observational evidence has suggested an association between smoking and inflammatory bowel disease (IBD).

METHODS

We used observational techniques followed by Mendelian randomization to explore whether smoking is a causal factor in the development of IBD and its subtypes.

RESULTS

In those who have ever smoked, we observed increased risk of IBD and, in current smokers, we observed increased risk of Crohn disease and decreased risk of ulcerative colitis. However, our Mendelian randomization analyses found little evidence that smoking affects the development of IBD.

CONCLUSION

Overall, our results suggest that smoking does not causally influence the risk of IBD.

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.

British Society of Gastroenterology consensus guidelines on the management of inflammatory bowel disease in adults

Ulcerative colitis and Crohn's disease are the principal forms of inflammatory bowel disease. Both represent chronic inflammation of the gastrointestinal tract, which displays heterogeneity in inflammatory and symptomatic burden between patients and within individuals over time. Optimal management relies on understanding and tailoring evidence-based interventions by clinicians in partnership with patients. This guideline for management of inflammatory bowel disease in adults over 16 years of age was developed by Stakeholders representing UK physicians (British Society of Gastroenterology), surgeons (Association of Coloproctology of Great Britain and Ireland), specialist nurses (Royal College of Nursing), paediatricians (British Society of Paediatric Gastroenterology, Hepatology and Nutrition), dietitians (British Dietetic Association), radiologists (British Society of Gastrointestinal and Abdominal Radiology), general practitioners (Primary Care Society for Gastroenterology) and patients (Crohn's and Colitis UK). A systematic review of 88 247 publications and a Delphi consensus process involving 81 multidisciplinary clinicians and patients was undertaken to develop 168 evidence- and expert opinion-based recommendations for pharmacological, non-pharmacological and surgical interventions, as well as optimal service delivery in the management of both ulcerative colitis and Crohn's disease. Comprehensive up-to-date guidance is provided regarding indications for, initiation and monitoring of immunosuppressive therapies, nutrition interventions, pre-, peri- and postoperative management, as well as structure and function of the multidisciplinary team and integration between primary and secondary care. Twenty research priorities to inform future clinical management are presented, alongside objective measurement of priority importance, determined by 2379 electronic survey responses from individuals living with ulcerative colitis and Crohn's disease, including patients, their families and friends.

British Society of Gastroenterology consensus guidelines on the management of inflammatory bowel disease in adults

Ulcerative colitis and Crohn's disease are the principal forms of inflammatory bowel disease. Both represent chronic inflammation of the gastrointestinal tract, which displays heterogeneity in inflammatory and symptomatic burden between patients and within individuals over time. Optimal management relies on understanding and tailoring evidence-based interventions by clinicians in partnership with patients. This guideline for management of inflammatory bowel disease in adults over 16 years of age was developed by Stakeholders representing UK physicians (British Society of Gastroenterology), surgeons (Association of Coloproctology of Great Britain and Ireland), specialist nurses (Royal College of Nursing), paediatricians (British Society of Paediatric Gastroenterology, Hepatology and Nutrition), dietitians (British Dietetic Association), radiologists (British Society of Gastrointestinal and Abdominal Radiology), general practitioners (Primary Care Society for Gastroenterology) and patients (Crohn's and Colitis UK). A systematic review of 88 247 publications and a Delphi consensus process involving 81 multidisciplinary clinicians and patients was undertaken to develop 168 evidence- and expert opinion-based recommendations for pharmacological, non-pharmacological and surgical interventions, as well as optimal service delivery in the management of both ulcerative colitis and Crohn's disease. Comprehensive up-to-date guidance is provided regarding indications for, initiation and monitoring of immunosuppressive therapies, nutrition interventions, pre-, peri- and postoperative management, as well as structure and function of the multidisciplinary team and integration between primary and secondary care. Twenty research priorities to inform future clinical management are presented, alongside objective measurement of priority importance, determined by 2379 electronic survey responses from individuals living with ulcerative colitis and Crohn's disease, including patients, their families and friends.

Impact of smoking cigarette on the mRNA expression of cytokines in mucosa of inflammatory bowel disease

It is well known that smoking is the risk factor in the development and clinical course of Crohn s disease (CD), but on the other hand, smoking is a protective factor against ulcerative colitis (UC). The pathways that are influenced by smoking in CD and UC are poorly understood. The aim of our study was to analyse the influence of smoking on the mRNA expression of cytokines in mucosa in patients with CD and UC. We performed a cross-sectional study. The cohort consisted of 86 IBD patients (48 CD patients and 38 UC patients) and took place at the IBD Centre at the University Hospital Bratislava-Ružinov. We took the demographic and clinical data of each patient, including information about their smoking habits. We performed a colonoscopy on each patient and took biopsies from both inflamed and non-inflamed sigma (CD, UC) and terminal ileum (CD). mRNA was extracted from mucosal biopsy samples for each cytokine and was normalized to a housekeeping gene (GAPDH). Finally, we compared the mRNA expression of target cytokines in the mucosa of smokers and non-smokers in IBD patients. Smokers with Crohn s disease have a significantly higher mRNA expression of pro-inflammatory cytokine TNF ? (p=0.003) in inflamed mucosa in sigma compared with non-smokers. In smokers with ulcerative colitis, we observed significantly higher mRNA expression of anti-inflammatory cytokine IL 10 (p=0.022) in non-inflamed mucosa of sigma. Similarly, smokers with UC have a significantly decreased mRNA expression of cytokine TLR 2 (p=0.024) and CCR1 (p=0.049) in non-inflamed mucosa of sigma. Based on our results, smoking has a positive influence on cessation and the clinical course of UC due to the stimulation of anti-inflammatory cytokine IL 10 in mucosa. On the other hand, smokers with CD have a higher expression of pro-inflammatory cytokine TNF ?, which could be associated with a worsening of the disease and response to therapy.

Inflammatory bowel disease and the risk for cardiovascular disease: Does all inflammation lead to heart disease?

Inflammation has a strong role in the development of atherosclerotic cardiovascular disease (ASCVD). Several systemic inflammatory conditions have been linked to an increased risk of ASCVD; however, this has not been well established in Inflammatory Bowel Disease (IBD). IBD is comprised of Ulcerative Colitis and Crohn's disease, both of which involve chronic inflammation of the intestinal tract, often with evidence of systemic involvement. Several ASCVD risk factors such as smoking, diabetes, poor diet and the presence of obesity may increase the risk of ASCVD in patients suffering from IBD, despite a lower prevalence of hypertension and hypercholesterolemia. Medications used to treat IBD and target inflammation, such as steroids, may also accelerate the risk of the risk for ASCVD heart failure while exacerbating ASCVD risk factors. Several studies have demonstrated an elevated risk of acute myocardial infarction and stroke in these patients, most notably in women and in younger patients. Some cohort studies have also suggested a link between IBD and both atrial fibrillation and heart failure, particularly during periods of active flares. All IBD patients, particularly younger individuals, should be screened for ASCVD risk factors with aggressive risk factor modification to reduce the risk of cardiovascular events. Further research is needed to identify how to prevent and treat cardiovascular events that occur in patients with IBD, particularly during active flares.

Diet and inflammatory bowel disease: The Asian Working Group guidelines

INTRODUCTION

These Asian Working Group guidelines on diet in inflammatory bowel disease (IBD) present a multidisciplinary focus on clinical nutrition in IBD in Asian countries.

METHODOLOGY

The guidelines are based on evidence from existing published literature; however, if objective data were lacking or inconclusive, expert opinion was considered. The conclusions and 38 recommendations have been subject to full peer review and a Delphi process in which uniformly positive responses (agree or strongly agree) were required.

RESULTS

Diet has an important role in IBD pathogenesis, and an increase in the incidence of IBD in Asian countries has paralleled changes in the dietary patterns. The present consensus endeavors to address the following topics in relation to IBD: (i) role of diet in the pathogenesis; (ii) diet as a therapy; (iii) malnutrition and nutritional assessment of the patients; (iv) dietary recommendations; (v) nutritional rehabilitation; and (vi) nutrition in special situations like surgery, pregnancy, and lactation.

CONCLUSIONS

Available objective data to guide nutritional support and primary nutritional therapy in IBD are presented as 38 recommendations.

Late-Onset Crohn's Disease Is A Subgroup Distinct in Genetic and Behavioral Risk Factors With UC-Like Characteristics

BACKGROUND

Age of onset is linked to variations in clinical phenotypes and natural history in Crohn's disease (CD). We aim to define etiologically more homogenous subgroups in CD based on ages of onset.

METHODS

We examined the distribution of CD polygenetic risk score (PRS) across ages of diagnosis in a Caucasian cohort of 2344 independent CD patients. We identified subgroups with a distinct distribution of PRS and compared those groups in genetics, demographic characteristics, clinical subphenotypes, and serological markers. The results were replicated in an independent cohort of 13,065 CD patients from the International Inflammatory Bowel Diseases Genetic Consortium (IIBDGC).

RESULTS

We identified a late-onset (LO) subgroup in CD (age at diagnosis ≥ 55 years) with significantly lower PRS compared with the intermediate group (age at diagnosis between 5 and 55 years) in both cohorts. Smoking cessation, a risk factor for ulcerative colitis (UC) and protective factor for CD, had a higher rate in this LO subgroup in comparison with the intermediate group. We also compared the LO group with the intermediate group, and, consistent with previous reports, the LO group more often had colonic CD, had less penetrating disease behavior, and had less need for surgery. Serological analysis showed that LO CD patients were more antineutrophil cytoplasmic antibody positive and less antisaccharomyces cerevisiae antibody positive compared with the intermediate group. Variance component analysis indicated that overall genetic contribution to LO CD was lower relative to the middle group, and genetic heterogeneity testing indicated that LO CD was different from the middle group in underlying genetic architecture.

CONCLUSIONS

Late-onset CD is subgroup distinct in genetic and behavioral risk factors with UC-like characteristics. 10.1093/ibd/izy148_video1izy148.video15791413461001.

Increased risk of acute arterial events in young patients and severely active IBD: a nationwide French cohort study

OBJECTIVE

Magnitude and independent drivers of the risk of acute arterial events in IBD are still unclear. We addressed this question in patients with IBD compared with the general population at a nationwide level.

DESIGN

Using the French National Hospital Discharge Database from 2008 to 2013, all patients aged 15 years or older and diagnosed with IBD were identified and followed up until 31 December 2013. The rates of incident acute arterial events were calculated and the impact of time with active disease (period around hospitalisation for IBD flare or IBD-related surgery) on the risk was assessed by Cox regression adjusted for traditional cardiovascular risk factors.

RESULTS

Among 210 162 individuals with IBD (Crohn's disease (CD), n=97 708; UC, n=112 454), 5554 incident acute arterial events were identified. Both patients with CD and UC had a statistically significant overall increased risk of acute arterial events (standardised incidence ratio (SIR) 1.35; 95% CI 1.30 to 1.41 and SIR 1.10; 95 CI 1.06 to 1.13, respectively). The highest risk was observed in patients under the age of 55 years, both in CD and UC. The 3-month periods before and after IBD-related hospitalisation were associated with an increased risk of acute arterial events in both CD and UC (HR 1.74; 95 CI 1.44 to 2.09 and 1.87; 95% CI 1.58 to 2.22, respectively).

CONCLUSION

Patients with IBD are at increased risk of acute arterial events, with the highest risk in young patients. Disease activity may also have an independent impact on the risk.

Combined Endoscopic/Sonographic-based Risk Matrix Model for Predicting One-year Risk of Surgery: A Prospective Observational Study of a Tertiary Centre Severe/Refractory Crohn's Disease Cohort

BACKGROUND

In the management of Crohn's disease [CD] patients, having a simple score combining clinical, endoscopic, and imaging features to predict the risk of surgery could help to tailor treatment more effectively.

AIMS

We aimed to prospectively evaluate the 1-year risk factors for surgery in refractory/severe CD and to generate a risk matrix for predicting the probability of surgery at 1 year.

METHODS

CD patients needing a disease re-assessment at our tertiary inflammatory bowel disease [IBD] centre underwent clinical, laboratory, endoscopic, and bowel sonography [BS] examinations within 1 week. The optimal cut-off values in predicting surgery were identified using receiver operating characteristic [ROC] curves for the Simple Endoscopic Score for CD [SES-CD], bowel wall thickness [BWT] at BS, and small bowel CD extension at BS. Binary logistic regression and Cox regression were then carried out. Finally, the probabilities of surgery were calculated for selected baseline levels of covariates and results were arranged in a prediction matrix.

RESULTS

Of 100 CD patients, 30 underwent surgery within 1 year. SES-CD ≥9 (odds ratio [OR] 15.3; p <0.001], BWT ≥7 mm [OR 15.8; p <0.001], small bowel CD extension at BS ≥33 cm [OR 8.23; p <0.001], and stricturing/penetrating behaviour [OR 4.3; p <0.001] were the only independent factors predictive of surgery at 1 year, based on binary logistic and Cox regressions. Our matrix model combined these risk factors, and the probability of surgery ranged from 0.48% to 87.5% [16 combinations].

CONCLUSIONS

Our risk matrix combining clinical, endoscopic, and ultrasonographic findings can accurately predict the 1-year risk of surgery in patients with severe/refractory CD requiring a disease re-evaluation. This tool could be of value in clinical practice, serving as the basis for a tailored management of CD patients.

Evidence-based clinical practice guidelines for inflammatory bowel disease

Inflammatory bowel disease (IBD) is a chronic disorder involving mainly the intestinal tract, but possibly other gastrointestinal and extraintestinal organs. Although etiology is still uncertain, recent knowledge in pathogenesis has accumulated, and novel diagnostic and therapeutic modalities have become available for clinical use. Therefore, the previous guidelines were urged to be updated. In 2016, the Japanese Society of Gastroenterology revised the previous versions of evidence-based clinical practice guidelines for ulcerative colitis (UC) and Crohn's disease (CD) in Japanese. A total of 59 clinical questions for 9 categories (1. clinical features of IBD; 2. diagnosis; 3. general consideration in treatment; 4. therapeutic interventions for IBD; 5. treatment of UC; 6. treatment of CD; 7. extraintestinal complications; 8. cancer surveillance; 9. IBD in special situation) were selected, and a literature search was performed for the clinical questions with use of the MEDLINE, Cochrane, and Igaku Chuo Zasshi databases. The guidelines were developed with the basic concept of the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) system. Recommendations were made using Delphi rounds. This English version was produced and edited based on the existing updated guidelines in Japanese.

Modifiable Environmental Factors in Inflammatory Bowel Disease

PURPOSE OF REVIEW

Environmental factors may influence predisposition to develop inflammatory bowel diseases (Crohn's disease, ulcerative colitis) or alter its natural history by modification of both the host immune response and intestinal microbial composition. The purpose of this review is to translate such evidence into clinical practice by a focus on interventional studies that have modified such environmental influences to improve disease outcomes.

RECENT FINDINGS

Several environmental influences have been identified in the recent literature including tobacco use, diet, antibiotics, vitamin D deficiency, stress, appendectomy, and oral contraceptive use. Some risk factors have similar influences on both Crohn's disease and ulcerative colitis while others are disease-specific or have divergent effects. Emerging epidemiologic evidence has confirmed the association of many of these factors with incident disease using prospective data. In addition, laboratory data has supported their mechanistic plausibility and relevance to intestinal inflammation.

Risk Factors for the Development of Fistulae and Stenoses in Crohn Disease Patients in the Swiss Inflammatory Bowel Disease Cohort

Background

Fistulae and stenoses represent frequent and severe complications in patients with Crohn disease (CD). Our study aimed to identify risk factors for fistula and stenosis formation in CD patients.

Summary

We retrieved data of 1,600 CD patients from the nationwide Swiss Inflammatory Bowel Disease Cohort Study (SIBDCS). The risk for fistulae and stenoses in relation to gender, age at diagnosis, smoking status at diagnosis, and ileal involvement at diagnosis were analyzed. In the multivariate analysis, female gender showed a lower risk for developing perianal and any fistula (risk ratio [RR] 0.721, 95% confidence interval [CI] 0.582-0.893, p = 0.003 and RR 0.717, 95% CI 0.580-0.888, p = 0.002, respectively), and older age at diagnosis showed a lower risk for developing perianal fistula (RR 0.661, 95% CI 0.439-0.995, p = 0.047). Furthermore, ileal involvement was associated with a lower risk for perianal fistula (RR 0.713, 95% CI 0.561-0.906, p = 0.006), a lower risk for any fistula (RR 0.709, 95% CI 0.558-0.901, p = 0.005), and a higher risk for stenosis (RR 2.170, 95% CI 1.728-2.725, p < 0.001).

Key Messages

In the nationwide SIBDCS, younger age at diagnosis and male gender were risk factors for developing perianal and nonperianal fistulae. Additionally, ileal involvement was revealed to be a potent risk factor (RR 2.170) for developing a stenosis.

[Smoking, smoking cessation and Crohn's disease]

CONTEXT

Smoking whose prevalence is higher in patients with Crohn's disease (CD) worsens its evolution. Ulcerative colitis mostly affect non- or ex-smokers; smoking may improve the course of the disease.

OBJECTIVES

Systematic literature review of data on the relationship between smoking, smoking cessation and Crohn'disease.

DOCUMENTARY SOURCES

Medline, on the period 1980-2015 with the keywords "Crohn's disease" or "inflammatory bowel disease" and "smoking" or "smoking cessation"; limits "Title/Abstract"; the selected languages were English or French.

STUDY SELECTION

Among 1315 articles, 168 abstracts have given rise to a dual reading to select 69 studies (case-control, retrospective, reviews or meta-analysis). Data were extracted using a reading gate.

RESULTS

Smoking increases the risk of complications, recurrences and resort of surgery, corticosteroids or immunosuppressants. These deleterious effects are more common in women. Stopping smoking improves the course of the disease and represents an essential component of its management.

LIMITS

Heterogeneity of the studies collected according to the type, population characteristics, definition of smoking status and the validation of smoking cessation.

CONCLUSION

Smokers suffering from CD must routinely be made aware of the disadvantages of smoking, benefits of abstinence and helped to quit smoking.

Impact of Smoking Cessation on the Clinical Course of Crohn's Disease Under Current Therapeutic Algorithms: A Multicenter Prospective Study

OBJECTIVES

Given the importance of tobacco smoking (TS) as the only environmental factor repeatedly linked to the development of the Crohn's disease (CD), it is surprising that very few prospective studies have assessed whether TS is associated with an increased frequency of clinical relapse. Our aim was to evaluate the current impact of TS on disease relapse and the clinical benefit of quitting smoking in the present era of widespread use of anti-TNF drugs and immunosuppressants.

METHODS

This was a multicenter prospective cohort study, which included 573 CD patients in clinical remission with various smoking habits. All smokers were advised to quit. Patients not exposed to tobacco before inclusion (non- and former smokers), continuing smokers, and quitters were compared regarding differences in disease outcomes during a follow-up of 4 years.

RESULTS

A total of 148 continuing smokers, 190 nonsmokers, 160 former smokers, and 75 quitters were included. In comparison with nonsmokers, continuing smokers relapsed more frequently with an incidence rate ratio of 1.53 (95% confidence interval (CI): 1.10-2.17). Former smokers and quitters had similar relapse incidences compared with nonsmokers. Smoking was an independent predictor for disease relapse in the multivariate analysis (hazard ratio: 1.58 (95% CI 1.20-2.09). In the time-dependent analysis, continuing smokers had earlier relapse, regardless of anti-TNF or immunosuppressant use.

CONCLUSIONS

Continuing smokers have more disease relapses, and patients who quit smoking have a similar relapse incidence compared with nonsmokers.

Systematic review with meta-analysis: the adverse effects of tobacco smoking on the natural history of Crohn's disease

BACKGROUND

Tobacco smoking is a well-established risk factor for the development of Crohn's disease, and this may lead to a more complicated disease course. However, recent evidence suggests that many patients with Crohn's disease are unaware of this fact.

AIM

To perform a systematic review and meta-analysis of the effects of smoking on disease course in Crohn's disease.

METHODS

A search of MEDLINE, EMBASE and EMBASE classic was carried out (up to July 2015) to identify observational studies reporting data on smoking and rates of surgery or flares of disease activity in patients with Crohn's disease. Dichotomous data were pooled to obtain odds ratios (ORs) for flares of disease activity or need for surgery, with 95% confidence intervals (CIs).

RESULTS

The search identified 33 eligible studies. Compared with nonsmokers, smokers had increased odds of flare of disease activity (OR, 1.56; 95% CI, 1.21-2.01), flare after surgery (OR, 1.97; 95% CI, 1.36-2.85), need for first surgery (OR, 1.68; 95% CI, 1.33-2.12) and need for second surgery (OR, 2.17; 95% CI, 1.63-2.89). The odds of these outcomes among ex-smokers diminished upon smoking cessation, with ORs comparable to those among nonsmokers and, in the case of flare or second surgery, significantly lower than smokers.

CONCLUSIONS

Smokers with Crohn's disease have a more complicated disease course than nonsmokers, and quitting smoking may ameliorate this. Patients should be reminded of the detrimental effects of smoking on the course of their disease, and smoking cessation advice should be provided to reduce disease burden and costs in these patients.

Microbiome-Epigenome Interactions and the Environmental Origins of Inflammatory Bowel Diseases

The incidence of pediatric inflammatory bowel disease (IBD), which includes Crohn disease and ulcerative colitis, has risen alarmingly in the Western and developing world in recent decades. Epidemiologic (including monozygotic twin and migrant) studies highlight the substantial role of environment and nutrition in IBD etiology. Here we review the literature supporting the developmental and environmental origins hypothesis of IBD. We also provide a detailed exploration of how the human microbiome and epigenome (primarily through DNA methylation) may be important elements in the developmental origins of IBD in both children and adults.

Influence of environmental factors on the onset and course of inflammatory bowel disease

Numerous environmental factors have been linked with inflammatory bowel disease. These include smoking, diet, hygiene, drugs, geographical and psychosocial factors. These factors may either increase the risk of or protect against developing this condition and can also affect the course of illness in a positive or negative manner. A number of studies have examined the influence of environmental factors on inflammatory bowel diseases as a whole as well as on ulcerative colitis and Crohn’s disease separately. As there are differences in the pathogenesis of ulcerative colitis and Crohn’s disease, the effect of environmental factors on their onset and course is not always similar. Some factors have shown a consistent association, while reports on others have been conflicting. In this article we discuss the current evidence on the roles of these factors on inflammatory bowel disease, both as causative/protective agents and as modifiers of disease course.

Environmental factors in the relapse and recurrence of inflammatory bowel disease: a review of the literature

INTRODUCTION

The causes of relapse in patients with Crohn's disease (CD) and ulcerative colitis (UC) are largely unknown. This paper reviews the epidemiological and clinical data on how medications (non-steroidal anti-inflammatory drugs, estrogens and antibiotics), lifestyle factors (smoking, psychological stress, diet and air pollution) may precipitate clinical relapses and recurrence. Potential biological mechanisms include: increasing thrombotic tendency, imbalances in prostaglandin synthesis, alterations in the composition of gut microbiota, and mucosal damage causing increased permeability.

RESULTS

The clinical epidemiological data consistently reports positive associations between smoking and relapses in CD, and inverse ones with UC. For NSAIDs and estrogens, the epidemiological findings are inconsistent, although general antibiotic use was associated with a reduced risk of relapse in CD. High levels of stress were positively associated with relapse, although psychological interventions did not have therapeutic benefits. The limited work on diet has reported sulphur-containing foods are positively associated with relapse in UC, but there is no work in CD. Ecological data reported positive correlations between air pollution levels and IBD hospitalisations.

CONCLUSIONS

In the future, to clarify this area, more clinical epidemiological work is required where detailed drug types and doses, and complete dietary intakes are measured, in specific forms of IBD. Such work could provide guidance to both patients and doctors to help maintain remission.

Smoking cessation alters intestinal microbiota: insights from quantitative investigations on human fecal samples using FISH

BACKGROUND

There has been a dramatic increase in investigations on the potential mechanistic role of the intestinal microbiota in various diseases and factors modulating intestinal microbial composition. We recently reported on intestinal microbial shifts after smoking cessation in humans. In this study, we aimed to conduct further microbial analyses and verify our previous results obtained by pyrosequencing using a direct quantitative microbial approach.

METHODS

Stool samples of healthy smoking human subjects undergoing controlled smoking cessation during a 9-week observational period were analyzed and compared with 2 control groups, ongoing smoking and nonsmoking subjects. Fluorescence in situ hybridization was applied to quantify specific bacterial groups.

RESULTS

Intestinal microbiota composition was substantially altered after smoking cessation as characterized by an increase in key representatives from the phyla of Firmicutes (Clostridium coccoides, Eubacterium rectale, and Clostridium leptum subgroup) and Actinobacteria (HGC bacteria and Bifidobacteria) as well as a decrease in Bacteroidetes (Prevotella spp. and Bacteroides spp.) and Proteobacteria (β- and γ-subgroup of Proteobacteria).

CONCLUSIONS

As determined by fluorescence in situ hybridization, an independent direct quantitative microbial approach, we could confirm that intestinal microbiota composition in humans is influenced by smoking. The characteristics of observed microbial shifts suggest a potential mechanistic association to alterations in body weight subsequent to smoking cessation. More importantly, regarding previously described microbial hallmarks of dysbiosis in inflammatory bowel diseases, a variety of observed microbial alterations after smoking cessation deserve further consideration in view of the divergent effect of smoking on the clinical course of Crohn's disease and ulcerative colitis.

Cigarette smoking and gastrointestinal diseases: the causal relationship and underlying molecular mechanisms (review)

Cigarette smoking is an important risk factor for gastrointestinal (GI) disorders, including peptic ulcers, inflammatory bowel diseases, such as Crohn's disease and cancer. In this review, the relationship between smoking and GI disorders and the underlying mechanisms are discussed. It has been demonstrated that cigarette smoking is positively associated with the pathogenesis of peptic ulcers and the delay of ulcer healing. Mechanistic studies have shown that cigarette smoke and its active ingredients can cause mucosal cell death, inhibit cell renewal, decrease blood flow in the GI mucosa and interfere with the mucosal immune system. Cigarette smoking is also an independent risk factor for various types of cancer of the GI tract. In this review, we also summarize the mechanisms through which cigarette smoking induces tumorigenesis and promotes the development of cancer in various sections of the GI tract. These mechanisms include the activation of nicotinic acetylcholine receptors, the formation of DNA adducts, the stimulation of tumor angiogenesis and the modulation of immune responses in the GI mucosa. A full understanding of these pathogenic mechanisms may help us to develop more effective therapies for GI disorders in the future.

Smoking in inflammatory bowel disease: impact on disease course and insights into the aetiology of its effect

The chronic intestinal inflammation that characterises Crohn's disease and ulcerative colitis arises from a complex interplay between host genotype, the immune system, and the intestinal microbiota. In addition, environmental factors such as smoking impact on disease onset and progression. Individuals who smoke are more likely to develop Crohn's disease, and smoking is associated with recurrence after surgery and a poor response to medical therapy. Conversely, smoking appears protective against ulcerative colitis and smokers are less likely to require colectomy. The mechanism by which smoking exerts its impact on disease and the rational for the dichotomous effect in patients with Crohn's disease and ulcerative colitis is not clear. Recent evidence suggests that smoking induces alterations to both the innate and acquired immune system. In addition, smoking is associated with a distinct alteration in the intestinal microbiota both in patients with active Crohn's disease and healthy subjects.

Can we predict the high-risk patient?

BACKGROUND

While therapeutic strategies able to change the natural history of inflammatory bowel diseases (IBD) are being developed, factors predicting aggressive disease are needed to be able to choose the appropriate therapeutic strategy for the individual patient based on the risk/benefit ratio. The aim of this review is to focus on the tools assisting the clinician in routine practice regarding the prediction of disease evolution.

METHODS

A literature review was performed, which was mainly based on PubMed search, using the following terms: Crohn's disease, ulcerative colitis, inflammatory bowel disease, genetics, serology, biomarkers, endoscopy, C-reactive protein, faecal calprotectin, disease evolution and complications.

RESULTS

For the prediction of disease evolution, clinical characteristics, particularly disease location and behaviour, are probably currently the most useful. In addition, a series of biomarkers, including genetic, serological and inflammatory markers, as well as characteristics of endoscopic lesions may have an added value.

CONCLUSIONS

Simple clinical, biological and endoscopic tools may help the clinician in predicting disease evolution in IBD. However, these tools are still insufficient, and prospective evaluation of new genetic and biological markers are needed.

Genetic polymorphisms in metabolizing enzymes modifying the association between smoking and inflammatory bowel diseases

BACKGROUND

Cigarette smoking is a well-established environmental risk factor for Crohn's disease (CD) and ulcerative colitis (UC). The exact mechanism of its effect remains unexplained. Genetic polymorphisms in metabolizing enzymes may influence susceptibility to the effect of smoking and shed light on its mechanism of action.

METHODS

We used a prospective cohort of patients with CD, UC, and healthy controls. Smoking status was defined as current, former, or never smoking. Patients were genotyped for polymorphisms in CYP2A6, glutathione transferase enzymes (GSTP1 and GSTM1), NAD(P)H quinone oxidoreductase (NQO), and heme oxygenase 1 using a Sequenom platform. Multivariate logistic regression models with CD or UC as the outcome, stratified by genotype, were developed and interaction P-values calculated.

RESULTS

Our study included 634 patients with CD, 401 with UC, and 337 healthy controls. Ever smokers had an increased risk of CD (odds ratio = 3.88, 95% confidence interval = 2.35-6.39) compared with nonsmokers among patients with AG/AA genotypes at CYP2A6. However, ever smoking was not associated with CD among patients with the AA genotype (Pinteraction = 0.001). Former smoking was associated with an increased risk for UC only in the presence of GG/AG genotypes for GSTP1 but not in those with the AA genotype (Pinteraction = 0.012). Polymorphisms at the NQO and HMOX loci did not demonstrate a statistically significant interaction with smoking and risk of CD or UC.

CONCLUSIONS

Genetic polymorphisms in metabolizing enzymes may influence the association between smoking and CD and UC. Further studies of gene-environment interaction in inflammatory bowel disease are warranted.

Smoking does influence disease behaviour and impacts the need for therapy in Crohn's disease in the biologic era

BACKGROUND

Recently, the notion that smoking may adversely affect Crohn's disease (CD) outcomes has been challenged by the suggestion that the widespread use of immunosuppressants and anti-TNF drugs might offset the adverse effects of tobacco.

AIM

To reassess the influence of tobacco smoking on disease phenotype and complications on a time-dependent analysis, taking into account the different therapeutic interventions.

METHODS

We designed a retrospective cohort study of 3224 patients with Crohn's disease. The data were collected from the Spanish national inflammatory bowel disease registry (ENEIDA), including information regarding demographics, clinical characteristics, disease complications, therapeutic interventions and smoking status. Patients were classified as nonsmokers, smokers and former smokers, according to their present and past smoking habits.

RESULTS

In the univariate analysis, smokers had more strictures (22.6% vs. 19.3%, P < 0.05) and less colonic involvement (7.2% vs. 10.9%, P < 0.05), and were more frequently under treatment with steroids (91.6% vs. 85.8%, P < 0.05), immunosuppressants (73.5% vs. 63.6% P < 0.05) or anti-TNF drugs (31.4% vs. 25.1%, P < 0.05) than nonsmokers. In the time-dependent multivariate analysis, smokers were found to have a significantly decreased survival free of stricturing disease (HR: 1.5, CI 95% 1.18-1.90) or perianal complications (HR: 1.50, CI 95% 1.01-1.46), and had a higher risk for requiring thiopurine therapy (HR: 1.20, CI 95% 1.05-1.30).

CONCLUSION

These results suggest that, despite the widespread use of immunosuppressants and anti-TNF drugs, smokers with Crohn's disease still have a more severe disease course, with increased therapeutic requirements when compared with nonsmokers.

Is current smoking still an important environmental factor in inflammatory bowel diseases? Results from a population-based incident cohort

BACKGROUND

Previous studies suggest that smoking is an important environmental factor in inflammatory bowel diseases (IBDs), with dichotomous effects in ulcerative colitis (UC) and Crohn's disease (CD). The aim of this study was to analyze the relationship between smoking and IBD risk in a population-based database from Veszprem Province, which included incident cases diagnosed between January 1, 1977, and December 31, 2008.

METHODS

Data from 1420 incident patients were analyzed (UC: 914, age at diagnosis: 38.9 years; CD: 506, age at diagnosis: 31.5 years). Both inpatient and outpatient records were collected and comprehensively reviewed. Overall, smoking frequency in the adult general population was 36.1%.

RESULTS

Of patients with CD, 47.2% were current smokers at diagnosis. Smoking was more frequent in male patients (P = 0.002) and was associated with an increased risk of CD (odds ratio, 1.96; 95% confidence interval, 1.63-2.37; P < 0.001). In contrast, current smoking was protective against UC (odds ratio, 0.33; 95% confidence interval, 0.27-0.41). The effect of smoking was linked to gender (in CD, more deleterious in male patients) and age at diagnosis and was most prominent in young adults, with a difference already being seen in 18- to 19-year-olds. In CD, a change in disease behavior (P = 0.02), location from ileal or colonic to ileocolonic (P = 0.003), arthritis/arthropathy (P = 0.002), need for steroids (P = 0.06), or AZA (P = 0.038) was more common in current smokers. Smoking in UC was associated with more extensive disease (P = 0.01) and a tendency for decreased need for colectomy (P = 0.06).

CONCLUSIONS

Current smoking was associated with the risk of IBD. This effect was linked to gender and age at diagnosis and was most prominent in young adults. No association was observed in pediatric or elderly patients. The deleterious and protective effects of smoking on the course in CD and UC were partially confirmed.

Smoking cessation induces profound changes in the composition of the intestinal microbiota in humans

Background

The human intestinal microbiota is a crucial factor in the pathogenesis of various diseases, such as metabolic syndrome or inflammatory bowel disease (IBD). Yet, knowledge about the role of environmental factors such as smoking (which is known to influence theses aforementioned disease states) on the complex microbial composition is sparse. We aimed to investigate the role of smoking cessation on intestinal microbial composition in 10 healthy smoking subjects undergoing controlled smoking cessation.

Methods

During the observational period of 9 weeks repetitive stool samples were collected. Based on abundance of 16S rRNA genes bacterial composition was analysed and compared to 10 control subjects (5 continuing smokers and 5 non-smokers) by means of Terminal Restriction Fragment Length Polymorphism analysis and high-throughput sequencing.

Results

Profound shifts in the microbial composition after smoking cessation were observed with an increase of Firmicutes and Actinobacteria and a lower proportion of Bacteroidetes and Proteobacteria on the phylum level. In addition, after smoking cessation there was an increase in microbial diversity.

Conclusions

These results indicate that smoking is an environmental factor modulating the composition of human gut microbiota. The observed changes after smoking cessation revealed to be similar to the previously reported differences in obese compared to lean humans and mice respectively, suggesting a potential pathogenetic link between weight gain and smoking cessation. In addition they give rise to a potential association of smoking status and the course of IBD.

Clinical factors predictive of Crohn's disease complications and surgery

Crohn's disease (CD) is a progressive disease that is subdivided into three phenotypes: inflammatory, stricturing and penetrating. At diagnosis, most CD patients have inflammatory disease. However, the natural history of CD is one of progression over time to structural complications of the gastrointestinal tract (strictures and fistulae) requiring hospitalizations and surgeries. There is now evidence that early treatment with immunosuppressants and biologics can halt the development of inflammatory damage/fibrosis because of their potential to induce complete mucosal healing. This change in the natural course of CD, mediated by mucosal healing, is associated with a reduction in the incidence of serious complications (those requiring hospitalization and surgeries). Nevertheless, the clinical course of CD varies considerably from one patient to another, and the exact point at which immunosuppressants and/or biologics should be used has not yet been established. Given the difficulty in predicting which individuals will progress to complications and the fact that these therapeutic agents are associated with certain risks (lymphomas and opportunistic infections), efforts are underway to identify the risk factors that will facilitate the classification of patients into high-risk and low-risk groups at the time of diagnosis and to tailor therapy accordingly. This paper is a review of the currently available evidence on the clinical risk factors predictive of CD complications and surgery.

Environmental factors and their impact on the intestinal microbiota: a role for human disease?

The intestinal microbiota and its potential role in human health and disease have come into the focus of interest in recent years. An important prerequisite for the achieved advances with regard to a better characterization of its complex composition and influencing factors is the increasing availability and affordability of culture-independent methods, such as high-throughput sequencing technologies. We discuss some general aspects of the intestinal microbiota. Recent insights into its potential pathogenetic role in the metabolic syndrome and inflammatory bowel disease will also be discussed that imply an impact of smoking status and smoking cessation on intestinal microbial composition.

Effectiveness of concomitant enteral nutrition therapy and infliximab for maintenance treatment of Crohn's disease in adults

BACKGROUND

One of the problems associated with infliximab (IFX) treatment for Crohn's disease (CD) is loss of response during maintenance therapy.

AIMS

The aim of this multicenter, retrospective, cohort study was to determine whether enteral nutrition (EN) added to the IFX therapy regimen is effective for maintaining remission in adult CD patients.

METHODS

Patients with CD who had started IFX therapy between April 2003 and March 2008 at any one of the seven participating medical centers and who met the following inclusion criteria were enrolled in the study: remission after triple infusions of IFX followed by IFX maintenance therapy every 8 weeks, and follow-up data available for ≥ 1 year. Remission was defined as a C-reactive protein (CRP) level of <0.3 mg/dL, and recurrence was defined as an increase in CRP to ≥ 1.5 mg/dL or shortening of the IFX interval. Patients were classified by EN dosage into two groups (EN group and non-EN group). The cumulative remission period and related factors were analyzed.

RESULTS

Of the 102 adult CD patients who met the inclusion criteria, 45 were in the EN group and 57 were in the non-EN group. The cumulative remission rate was significantly higher in the EN group than in the non-EN group (P = 0.009). Multivariate analysis revealed that EN was the only suppressive factor for disease recurrence (P = 0.01).

CONCLUSIONS

The results demonstrate that among this CD patient cohort, EN combined with IFX maintenance treatment was clinically useful for maintaining remission.

Crohn's disease

Crohn's disease is a relapsing systemic inflammatory disease, mainly affecting the gastrointestinal tract with extraintestinal manifestations and associated immune disorders. Genome wide association studies identified susceptibility loci that--triggered by environmental factors--result in a disturbed innate (ie, disturbed intestinal barrier, Paneth cell dysfunction, endoplasmic reticulum stress, defective unfolded protein response and autophagy, impaired recognition of microbes by pattern recognition receptors, such as nucleotide binding domain and Toll like receptors on dendritic cells and macrophages) and adaptive (ie, imbalance of effector and regulatory T cells and cytokines, migration and retention of leukocytes) immune response towards a diminished diversity of commensal microbiota. We discuss the epidemiology, immunobiology, amd natural history of Crohn's disease; describe new treatment goals and risk stratification of patients; and provide an evidence based rational approach to diagnosis (ie, work-up algorithm, new imaging methods [ie, enhanced endoscopy, ultrasound, MRI and CT] and biomarkers), management, evolving therapeutic targets (ie, integrins, chemokine receptors, cell-based and stem-cell-based therapies), prevention, and surveillance.

The effect of aspirin and smoking on urinary excretion profiles of lactulose and mannitol in young women: toward a dynamic, aspirin augmented, test of gut mucosal permeability

BACKGROUND

We explored the temporal dynamics of the lactulose mannitol test and the influence of a single dose of aspirin.

METHODS

Twenty healthy female volunteers each received 600 mg aspirin or placebo in random sequence and were subsequently dosed with 10 g lactulose and 5 g mannitol, their urine collected every half hour for 6h.

KEY RESULTS

The lactulose:mannitol ratios (LMR) of urine samples collected over the entire 6-h period were significantly higher than those collected in the first 3 h. Greater quantities of mannitol were excreted over the first than the subsequent 3 h. A similar pattern of temporal variation in mannitol excretion was found in smokers and non-smokers and was maintained following administration of a single 600 mg dose of aspirin. The rates at which lactulose was excreted were relatively constant over the entire 6 h period of collection, but mean levels were increased over the entire 6 h following the administration of aspirin. The effect of aspirin did not differ significantly between smokers and non-smokers.

CONCLUSIONS & INFERENCES

  While the LMR test is sufficiently sensitive to reproducibly detect the increase in intestinal permeability resulting from a single 600 mg oral dose of aspirin, the temporal patterns of excretion of mannitol and lactulose differ both in the presence and absence of aspirin. Hence, variation in sampling period and in method of dosage are likely to influence the result and it is preferable to examine the patterns of absorption of component sugars separately with due regard to the method of dosage.

Impact of environmental and dietary factors on the course of inflammatory bowel disease

Besides their possible effects on the development of inflammatory bowel disease (IBD), some environmental factors can modulate the clinical course of both ulcerative colitis (UC) and Crohn’s disease (CD). This review is mainly devoted to describing the current knowledge of the impact of some of these factors on the outcome of IBD, with special emphasis on smoking and diet. Although the impact of smoking on the susceptibility to develop CD and UC is firmly established, its influence on the clinical course of both diseases is still debatable. In CD, active smoking is a risk factor for postoperative recurrence. Beyond this clinical setting, smoking cessation seems to be advantageous in those CD patients who were smokers at disease diagnosis, while smoking resumption may be of benefit in ex-smokers with resistant UC. The role of dietary habits on the development of IBD is far from being well established. Also, food intolerances are very frequent, but usually inconsistent among IBD patients, and therefore no general dietary recommendations can be made in these patients. In general, IBD patients should eat a diet as varied as possible. Regarding the possible therapeutic role of some dietary components in IBD, lessons should be drawn from the investigation of the primary therapeutic effect of enteral nutrition in CD. Low-fat diets seem to be particularly useful. Also, some lipid sources, such as olive oil, medium-chain triglycerides, and perhaps omega-3 fatty acids, might have a therapeutic effect. Fermentable fiber may have a role in preventing relapses in inactive UC.

Clinical predictors of aggressive/disabling disease: ulcerative colitis and crohn disease

Many clinical factors predict the aggressive course of CD. Younger age at initial diagnosis, the presence of perianal lesions, ileal involvement, smoking, and the need for therapy with corticosteroids are the major predictors of disabling disease or change of behavior to a more aggressive disease. On the other hand, treatment with azathioprine and biologic agents and colonic localization of disease are the major factors that are predictive of less aggressive CD course. The problem we face with determining the factors that increase the risk of disabling disease is that there is no standardized and consistent definition of disabling or aggressive disease. Only two studies analyzed predictors using the same definition of aggressive disease. Only Beaugerie and colleagues developed the score predictive of disabling disease based on three independent factors associated with disabling course that were present at the time of initial diagnosis of CD (requirement of corticosteroids, age less than 40 years, and presence of perianal disease). This score ranged from 0 to 3 points based on the presence of given parameters. The positive predictive value was 0.91 and 0.93 in patients having two or three risk factors, 0.61 for no factors present, and 0.67 for one factor present. In order to determine factors predictive of disabling CD there is a need to establish consistent definition of disabling disease with subsequent future studies on large group of patients to validate such definition and determine factors that may predict the aggressive course.