Smoking habit and load influence age at diagnosis and disease extent in ulcerative colitis

Nicotine improves DSS-induced colitis by inhibiting NLRP3 and altering gut microbiota

Ulcerative colitis (UC) is a chronic recurrent inflammatory disease affecting the rectum and colon. Numerous epidemiological studies have identified smoking as a protective factor for UC. Dysbiosis of intestinal microbiota and release of inflammatory factors are well-established characteristics associated with UC. Therefore, we have observed that nicotine exhibits the potential to ameliorate colitis symptoms in UC mice. Additionally, it exerts a regulatory effect on colonic microbiota dysbiosis by promoting the growth of beneficial bacteria while suppressing harmful bacteria. Combined in vivo and in vitro investigations demonstrate that nicotine primarily impedes the assembly of NLRP3, subsequently inhibiting downstream IL-1β secretion.

The Contribution of Genetic Risk and Lifestyle Factors in the Development of Adult-Onset Inflammatory Bowel Disease: A Prospective Cohort Study

INTRODUCTION

The joint associations across genetic risk, modifiable lifestyle factors, and inflammatory bowel disease (IBD) remains unclear.

METHODS

Genetic susceptibility to Crohn's disease (CD) and ulcerative colitis (UC) was estimated by polygenic risk scores and further categorized into high, intermediate, and low genetic risk categories. Weighted healthy lifestyle scores were constructed based on 5 common lifestyle factors and categorized into favorable (4 or 5 healthy lifestyle factors), intermediate (3 healthy lifestyle factors), and unfavorable (0-2 healthy lifestyle factors) groups. Cox proportional hazards regression model was used to estimate the hazard ratios (HR) and 95% confidence interval (CI) for their associations.

RESULTS

During the 12-year follow-up, 707 cases with CD and 1576 cases with UC were diagnosed in the UK Biobank cohort. Genetic risk and unhealthy lifestyle categories were monotonically associated with CD and UC risk with no multiplicative interaction between them. The HR of CD and UC were 2.24 (95% CI 1.75-2.86) and 2.15 (95% CI 1.82-2.53) for those with a high genetic risk, respectively. The HR of CD and UC for individuals with an unfavorable lifestyle were 1.94 (95% CI 1.61-2.33) and 1.98 (95% CI 1.73-2.27), respectively. The HR of individuals with a high genetic risk but a favorable lifestyle (2.33, 95% CI 1.58-3.44 for CD, and 2.05, 95% CI 1.58-2.66 for UC) were reduced nearly by half, compared with those with a high genetic risk but an unfavorable lifestyle (4.40, 95% CI 2.91-6.66 for CD and 4.44, 95% CI 3.34-5.91 for UC).

DISCUSSION

Genetic and lifestyle factors were independently associated with susceptibility to incident CD and UC. Adherence to a favorable lifestyle was associated with a nearly 50% lower risk of CD and UC among participants at a high genetic risk.

UK IBD Twin Registry: Concordance and Environmental Risk Factors of Twins with IBD

BACKGROUND AND AIMS

Twin studies have long been used to infer heritability. Within the 'omics era, twin cohorts have even greater research potential. This study describes the formation of the UK IBD Twin Registry and analysis of concordance and environmental factors.

METHOD

Twin pairs with IBD were recruited by advertising via IBD charities and social media, re-tracing a dormant IBD database and clinician referral. Details of zygosity, concordance, disease history and environmental factors were assessed. Pair concordance was calculated, and environmental factors were analysed with logistic regression models adjusted for zygosity and concordance.

RESULTS

Ninety-one twin pairs were included in the analysis; forty-two with CD and forty-nine with UC. More MZ twin pairs with CD were concordant compared with DZ pairs, thus inferring heritability (Chi-sq. 15.6. P < 0.001). In UC, MZ concordance was also numerically greater. Cigarette smoking was predictive of CD (OR 2.66, 95% CI 1.16 to 6.07 P = 0.02); there may be an independent association with cannabis smoking (OR 2.59 95% CI 0.89 to 7.55 P = 0.08). Breastfeeding was protective against UC (OR 0.48, 95% CI 0.25-0.93, P = 0.03), but not CD. Self-reports of less occurrences of gastroenteritis than peers were protective against future UC onset (OR 0.33 95% CI 0.15 to 0.74, P = 0.01). Method of delivery, parental attitudes towards hygiene and recall of diet did not impact future IBD concordance.

CONCLUSIONS

This study supports the heritability of IBD. Twin study analysis was able to elucidate environmental factors associated with IBD.

(RS)-bambuterol and its enantiomers: Potential improvement of (R)-bambuterol in mice with colitis

Bambuterol (BMB) has been used clinically to treat asthma due to its bronchodilation activity. However, the effect of BMB on ulcerative colitis (UC) has not been examined. The present work focused on the effects of enantiomeric BMB on UC. Acute UC was induced in mice by 3% dextran sulfate sodium (DSS), and (R)-, (S) and (RS)-BMB were orally administered. Body weight loss and the disease activity index (DAI) were measured once a day. Inflammatory factors were detected by ELISA and qRT-PCR. Histological evaluations of colon samples were performed. IL-6, STAT3, and RORγt pathway-related proteins were analyzed by western blotting. The results verified that colitis severity was dramatically ameliorated by (R)-BMB, which was significantlybetter than the effect of (RS)-BMB or (S)-BMB, as evidenced by body weight loss, DAI, colon length, spleen/body weight ratio and histopathological manifestations. Furthermore, (R)-BMB treatment significantly diminished the levels of inflammatory cytokines and macrophages infiltration in mice with colitis. Besides, treated with (R)-BMB obviously elevated the level of β2AR. In addition, (R)-BMB decreased the expression of IL-6, IL-17, retinoic acid receptor-related orphan receptor-gamma t (RORt), and phosphorylated STAT3 (p-STAT3) in a dose-dependent manner in the colon tissues. The efficacy of (R)-BMB was more notable than aminosalicylic acid (5-ASA). (R)-BMB is either butyrilcholinesterase inhibitor or β2AR agonist which offers new treatment of colitis.

Ethnic Differences in the Smoking-related Risk of Inflammatory Bowel Disease: A Systematic Review and Meta-analysis

BACKGROUND AND AIMS

The association between smoking and inflammatory bowel disease [IBD] relies on old meta-analyses including exclusively non-Jewish White populations. Uncertainty persists regarding the role of smoking in other ethnicities.

METHODS

We systematically searched Medline/PubMed, Embase, and Scopus for studies examining tobacco smoking and the risk of developing IBD, ie, Crohn's disease [CD] or ulcerative colitis [UC]. Two authors independently extracted study data and assessed each study's risk of bias. We examined heterogeneity and small-study effect, and calculated summary estimates using random-effects models. Stratified analyses and meta-regression were employed to study the association between study-level characteristics and effect estimates. The strength of epidemiological evidence was assessed through prespecified criteria.

RESULTS

We synthesised 57 studies examining the smoking-related risk of developing CD and UC. Non-Jewish White smokers were at increased risk of CD (29 studies; relative risk [RR]: 1.95, 95% confidence interval [CI]: 1.69‒2.24; moderate evidence). No association was observed in Asian, Jewish. and Latin-American populations [11 studies; RR: 0.97; 95% CI: 0.83-1.13], with no evidence of heterogeneity across these ethnicities. Smokers were at reduced risk of UC [51 studies; RR: 0.55, 95% CI: 0.48-0.64; weak evidence] irrespectively of ethnicity; however, cohort studies, large studies, and those recently published showed attenuated associations.

CONCLUSIONS

This meta-analysis did not identify any increased risk of CD in smokers in ethnicities other than non-Jewish Whites, and confirmed the protective effect of smoking on UC occurrence. Future research should characterise the genetic background of CD patients across different ethnicities to improve our understanding of the role of smoking in CD pathogenesis.

Expression of inflammatory mediators in biofilm samples and clinical association in inflammatory bowel disease patients-a preliminary study

OBJECTIVES

Inflammatory bowel disease (IBD) has multiple impacts on soft and hard tissues in the oral cavity. The aim of this study was to analyze the expression of cytokines in biofilm samples from patients suffering from IBD and compare them to healthy patients. It was hypothesized that different cytokine expression levels and clinical associations might be drawn.

MATERIAL AND METHODS

A total of 56 biofilm samples from three different patient cohorts (group 0 = healthy, HC n = 30; group 1 = Crohn's disease, CD, n = 19; group 2 = ulcerative colitis, UC, n = 7) were examined for the expression levels of the cytokine interleukins IL-2, -6, and -10; matrix metalloproteinases 7 and 9; and surface antigens CD90/CD11a by quantitative real-time PCR and according to clinical parameters (plaque index, BOP, PD, DMFT, CAL). Relative gene expression was determined using the ∆∆CT method.

RESULTS

The mean BOP values (p = 0.001) and PD (p = 0.000) were significantly higher in the CD group compared to controls. Expression of IL-10 was significantly higher in the CD (p = 0.004) and UC groups (p = 0.022). Expression of MMP-7 was significantly higher in the CD group (p = 0.032). IBD patients treated with TNF inhibitors (p = 0.007) or other immunosuppressants (p = 0.014) showed significant overexpression of IL-10 compared to controls.

CONCLUSION

Different expression levels of IL-10 and MMP-7 were detected in plaque samples from IBD patients. As only BOP was significantly increased, we conclude that no clinical impairment of periodontal tissue occurred in IBD patients.

CLINICAL RELEVANCE

With the worldwide increasing incidence of IBD, it is important to obtain insights into the effects of the disease on the oral cavity. The study was registered (01.09.2020) at the German clinical trial registry (DRKS00022956).

CLINICAL TRIAL REGISTRATION

The study is registered at the German clinical trial registry (DRKS00022956).

Segmental Histological Normalisation Occurs in Ulcerative Colitis but Does Not Improve Clinical Outcomes

BACKGROUND AND AIMS

Complete histological normalisation and reduction of inflammation severity in patients with ulcerative colitis are associated with improved clinical outcomes, but the clinical significance of normalisation of only segments of previously affected bowel is not known. We examined the prevalence, pattern, predictors, and clinical outcomes associated with segmental histological normalisation in in patients with ulcerative colitis.

METHODS

Medical records of patients with confirmed ulcerative colitis and more than one colonoscopy were sought. Segmental histological normalisation was defined as histological normalisation of a bowel segment [rectum, left-sided or right-sided colon] that had previous evidence of chronic histological injury. We assessed the variables influencing these findings and whether segmental normalisation was associated with improved clinical outcomes.

RESULTS

Of 646 patients, 32% had segmental and 10% complete histological normalisaton when compared with their maximal disease extent. Most [88%] had segmental normalisation in a proximal-to-distal direction. Others had distal-to-proximal or patchy normalisation. On multivariate analysis, only current smoking [p = 0.040] and age of diagnosis ≤16 years [p = 0.028] predicted segmental histological normalisation. Of 310 who were in clinical remission at initial colonoscopy, 77 [25%] experienced clinical relapse after median 1.3 [range 0.06-7.52] years. Only complete histological normalisation of the bowel was associated with improved relapse-free survival (hazard ratio [HR] 0.23; 95% confidence interval [CI] 0.08-0.68; p = 0.008].

CONCLUSIONS

Segmental histological normalisation occurs in 32% of patients with ulcerative colitis and is increased in those who smoke or were diagnosed at younger age. Unlike complete histological normalisation, segmental normalisation does not signal improved clinical outcomes.

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.

The role of sodium thiocyanate supplementation during dextran sodium sulphate-stimulated experimental colitis

Ulcerative colitis is a condition characterised by the infiltration of leukocytes into the gastrointestinal wall. Leukocyte-MPO catalyses hypochlorous acid (HOCl) and hypothiocyanous acid (HOSCN) formation from chloride (Cl^-) and thiocyanous (SCN^-) anions, respectively. While HOCl indiscriminately oxidises biomolecules, HOSCN primarily targets low-molecular weight protein thiols. Oxidative damage mediated by HOSCN may be reversible, potentially decreasing MPO-associated host tissue destruction. This study investigated the effect of SCN^- supplementation in a model of acute colitis. Female mice were supplemented dextran sodium sulphate (DSS, 3% w/v) in the presence of 10 mM Cl^- or SCN^- in drinking water ad libitum, or with salts (NaCl and NaSCN only) or water only (controls). Behavioural studies showed mice tolerated NaSCN and NaCl-treated water with water-seeking frequency. Ion-exchange chromatography showed increased fecal and plasma SCN^- levels in thiocyanate supplemented mice; plasma SCN^- reached similar fold-increase for smokers. Overall there was no difference in weight loss and clinical score, mucin levels, crypt integrity and extent of cellular infiltration between DSS/SCN^- and DSS/Cl^- groups. Neutrophil recruitment remained unchanged in DSS-treated mice, as assessed by fecal calprotectin levels. Total thiol and tyrosine phosphatase activity remained unchanged between DSS/Cl^- and DSS/SCN^- groups, however, colonic tissue showed a trend in decreased 3-chlorotyrosine (1.5-fold reduction, p < 0.051) and marked increase in colonic GCLC, the rate-limiting enzyme in glutathione synthesis. These data suggest that SCN^- administration can modulate MPO activity towards a HOSCN-specific pathway, however, this does not alter the development of colitis within a DSS murine model.

The impact of smoking and smoking cessation on disease outcomes in ulcerative colitis: a nationwide population-based study

BACKGROUND

Smokers are less likely to develop ulcerative colitis (UC) but the impact of smoking and subsequent cessation on clinical outcomes in UC is unclear.

AIM

To evaluate the effect of smoking status and smoking cessation on disease outcomes.

METHODS

Using a nationally representative clinical research database, we identified incident cases of UC during 2005-2016. Patients were grouped as never-smokers, ex-smokers and smokers based on smoking status recorded in the 2 years preceding UC diagnosis. We defined subgroups of persistent smokers and smokers who quit within 2 years after diagnosis. We compared the rates of overall corticosteroid use, corticosteroid-requiring flares, corticosteroid dependency, thiopurine use, hospitalisation and colectomy between these groups.

RESULTS

We identified 6754 patients with a new diagnosis of UC over the study period with data on smoking status, of whom 878 were smokers at diagnosis. Smokers had a similar risk of corticosteroid-requiring flares (OR 1.16, 95% CI 0.92-1.25), thiopurine use (HR 0.84, 95% CI 0.62-1.14), corticosteroid dependency (HR 0.85, 95% CI 0.60-1.11), hospitalisation (HR 0.92, 95% CI 0.72-1.18) and colectomy (HR 0.78, 95% CI 0.50-1.21) in comparison with never-smokers. Rates of flares, thiopurine use, corticosteroid dependency, hospitalisation and colectomy were not significantly different between persistent smokers and those who quit smoking after a diagnosis of UC.

CONCLUSIONS

Smokers and never-smokers with UC have similar outcomes with respect to flares, thiopurine use, corticosteroid dependency, hospitalisation and colectomy. Smoking cessation was not associated with worse disease course. The risks associated with smoking outweigh any benefits. UC patients should be counselled against smoking.

Aminosalicylates, thiopurines and methotrexate in inflammatory bowel disease: Is it possible to discontinue the treatment?

The current goals of treatment in inflammatory bowel disease, both Crohn's disease and ulcerative colitis, are to achieve clinical, endoscopic and ideally histological remission and improve the quality of life of these patients. Current therapies are effective in achieving remission in most cases, but there is a lack of clear guidelines on their optimal duration. This review aims to evaluate the current evidence on the withdrawal of therapy with 5-aminosalicylates, thiopurines and methotrexate. We also aim to identify which specific group of patients, while in remission and in the absence of risk factors, may be able to discontinue therapy without a significant risk of relapse.

Colectomy Rates in Ulcerative Colitis are Low and Decreasing: 10-year Follow-up Data From the Swiss IBD Cohort Study

OBJECTIVES

Previous population-based studies in patients with ulcerative colitis [UC] revealed variable colectomy rates and colectomy-associated risk factors. Over the past two decades, a decrease in colectomy rates was observed. We assessed risk factors and colectomy rates over time in UC in the Swiss Inflammatory Bowel Disease Cohort Study [SIBDCS].

METHODS

Prospectively collected SIBDCS data, including disease history, baseline characteristics at enrolment, and course of disease, were retrospectively analysed. Cumulative and adjusted annual colectomy rates were calculated.

RESULTS

Among 1245 UC patients analysed [54.6% male], 114 [9.2%] underwent colectomy. We observed 5-, 10-, 15-, and 20-year cumulative colectomy rates after diagnosis of 4.1%, 6.4%, 10.4%, and 14.4% of patients, respectively. Male sex (odds ratio [OR] 1.54; p = 0.035), pancolitis at diagnosis [OR = 2.16; p = 0.005], younger age at diagnosis [OR 0.89 per 5 years of age; p = 0.006] and presence of extraintestinal manifestations [EIM] [OR 2.30; p < 0.001] were risk factors for undergoing colectomy. We did not observe a significant protective effect of smoking on colectomy risk [OR 0.64; p = 0.106]. The majority of colectomies were performed within first 10 years of disease onset, with a rapidly decreasing colectomy rate after 15 years. In patients diagnosed after 2003, colectomy was performed much earlier during and individual's disease course. Nevertheless, we found a significantly decreasing trend in yearly colectomy rates over time after 2005.

CONCLUSIONS

Crude and adjusted colectomy rates in Swiss UC patients were lower than those reported previously in the literature, and decreased over time.

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.

DNA polymorphisms predict time to progression from uncomplicated to complicated Crohn's disease

OBJECTIVE

Most patients with Crohn's disease (CD) are diagnosed with the uncomplicated inflammatory form of the disease (Montreal stage B1). However, the majority of them will progress to complicated stricturing (B2) and penetrating (B3) CD during their lifetimes. The aim of our study was to identify the genetic factors associated with time to progression from uncomplicated to complicated CD.

PATIENTS AND METHODS

Patients with an inflammatory phenotype at diagnosis were followed up for 10 years. Genotyping was carried out using Illumina ImmunoChip. After quality control, association analyses, Bonferroni's adjustments, linear and Cox's regression, and Kaplan-Meier analysis were carried out for 111 patients and Manhattan plots were constructed.

RESULTS

Ten years after diagnosis, 39.1% of the patients still had the inflammatory form and 60.9% progressed to complicated disease, with an average time to progression of 5.91 years. Ileal and ileocolonic locations were associated with the complicated CD (P=1.08E-03). We found that patients with the AA genotype at single-nucleotide polymorphism rs16857259 near the gene CACNA1E progressed to the complicated form later (8.80 years) compared with patients with the AC (5.11 years) or CC (2.00 years) genotypes (P=3.82E-07). In addition, nine single-nucleotide polymorphisms (near the genes RASGRP1, SULF2, XPO1, ZBTB44, HLA DOA/BRD2, HLA DRB1/HLA DQA1, PPARA, PUDP, and KIAA1614) showed a suggestive association with disease progression (P<10). Multivariate Cox's regression analysis on the basis of clinical and genetic data confirmed the association of the selected model with disease progression (P=5.73E-16).

CONCLUSION

Our study confirmed the association between the locus on chromosome 1 near the gene CACNA1E with time to progression from inflammatory to stricturing or penetrating CD. Predicting the time to progression is useful to the clinician in terms of individualizing patients' management.

Current smoking improves ulcerative colitis patients' disease behaviour in the northwest of China

Introduction

The incidence of ulcerative colitis has increased tremendously over the past few decades, and caused much more attention in China. Several studies have revealed that both environmental and genetic factors play crucial roles in the formation and development of this disease. Among the environmental factors, the smoking condition is highly significant. Although current smoking has been associated with a protective effect on both the development and progression of ulcerative colitis (UC), the clinical characteristics of UC patients with current smoking in China is still unclear.

Aim

To clarify the relationship between current smoking and the UC in the northwest of China, patients diagnosed with ulcerative colitis in the General Hospital of Ningxia Medical University from 2003.03 to 2012.09 were assessed.

Material and methods

Data were collected about clinical features, cigarette smoking conditions, disease location, and therapeutic requirements. A total of 421 patients were included in this study, at diagnosis, 341 (81%) patients were non-smokers, and the current smokers amounted to 80 (19%).

Results

As for disease location, there were no differences between the current smokers and non-smokers regarding proctitis and extensive colitis, but the current smokers had less left-sided colitis than non-smokers (p = 0.049). Based on the Modified Mayo score, heavier smokers had lower scores than other smokers and non-smokers. For the therapeutic requirements, current smokers needed fewer corticosteroids than non-smokers (p = 0.048).

Conclusions

We found that current smoking is closely associated with a protective factor for UC.

Clinical Predictors of the Risk of Early Colectomy in Ulcerative Colitis: A Population-based Study

BACKGROUND

A subset of patients with ulcerative colitis (UC) will require colectomy within a few years of diagnosis. Thus, our aim was to determine the clinical predictors of early colectomy among patients with UC who are hospitalized with an acute flare.

METHODS

Using population-based surveillance (1996-2009), all adults (≥18 years) hospitalized for UC within 3 years of diagnosis (n = 489) were identified. The primary outcome was a colectomy within 3 years of diagnosis. All medical charts were reviewed. A logistic regression model evaluated clinical variables that predicted colectomy within 3 years of diagnosis, and adjusted odds ratios (ORs) with 95% confidence intervals (CIs) were reported.

RESULTS

Among patients admitted to hospital with UC within 3 years of diagnosis, 57.7% underwent colectomy, with the odds of colectomy decreasing by 12% per year. Early colectomy was more likely among patients aged 35 to 64 years versus 18 to 34 years (OR 2.18 [95% CI, 1.27-3.74]), males (OR 2.03 [95% CI, 1.24-3.34]), those with pancolitis (OR 5.38 [95% CI, 3.20-9.06]), and living in rural areas (OR 2.81 [95% CI, 1.49-5.29]). Prescription of infliximab before hospitalization increased odds of surgery (OR 5.12 [95% CI, 1.36-19.30]).

CONCLUSIONS

Patients hospitalized for UC have a high risk of early colectomy. This is particularly true in middle-aged men, those living in rural areas, and those without response to infliximab.

Effect of Alcoholic Intoxication on the Risk of Inflammatory Bowel Disease: A Nationwide Retrospective Cohort Study

PURPOSE

This study investigated whether alcoholic intoxication (AI) increases the risk of inflammatory bowel disease (IBD) by using a population-based database in Taiwan.

METHODS

This retrospective matched-cohort study included 57 611 inpatients with new-onset AI (AI cohort) and 230 444 randomly selected controls (non-AI cohort). Each patient was monitored for 10 years to individually identify those who were subsequently diagnosed with Crohn disease (CD) and ulcerative colitis (UC) during the follow-up period. Cox proportional hazard regression analysis was conducted to determine the risk of IBD in patients with AI compared with controls without AI.

RESULTS

The incidence rate of IBD during the 10-year follow-up period was 2.69 per 1 000 person-years and 0.49 per 1 000 person-years in the AI and non-AI cohorts, respectively. After adjustment for age, sex, and comorbidity, the AI cohort exhibited a 3.17-fold increased risk of IBD compared with the non-AI cohort (hazard ratio [HR] = 3.17, 95% confidence interval [CI] = 2.19-4.58). Compared with the non-AI cohort, the HRs of CD and UC were 4.40 and 2.33 for the AI cohort, respectively. After stratification for the severity of AI according to the duration of hospital stay, the adjusted HRs exhibited a significant correlation with the severity; the HRs of IBD were 1.76, 6.83, and 19.9 for patients with mild, moderate, and severe AI, respectively (p for the trend < .0001).

CONCLUSION

The risk of IBD was higher in patients with AI and increased with the length of hospital stay.

Systematic review with meta-analysis: the effect of tobacco smoking on the natural history of ulcerative colitis

BACKGROUND

Tobacco smoking is associated with a reduced risk of developing ulcerative colitis (UC). A high proportion of UC patients perceive a benefit in disease outcomes secondary to smoking. However, the effects of smoking on the natural history of UC are uncertain.

AIM

To conduct a systematic review and meta-analysis of the effects of tobacco smoking on the natural history of UC.

METHODS

A search of MEDLINE, EMBASE and EMBASE classic was carried out (up to December 2015) to identify observational studies reporting data on smoking and rates of colectomy, flare of disease activity, proximal disease extension, and development of pouchitis following panproctocolectomy and ileal pouch-anal anastomosis in patients with UC. Dichotomous data were pooled to obtain odds ratios (ORs), with 95% confidence intervals (CIs).

RESULTS

The search identified 16 eligible studies: five (2615 patients) studying colectomy; four (620 patients) reporting on flare of disease activity; four (687 patients) examining proximal disease extension and three (355 patients) assessing development of pouchitis. Compared with nonsmokers, the odds of colectomy (OR = 0.89; 95% CI 0.62-1.26), flare of disease activity (OR = 1.26; 95% CI 0.65-2.44), proximal extension of disease (OR = 0.57; 95% CI 0.20-1.66) or the development of pouchitis (OR = 0.57; 95% CI 0.21-1.53) were not significantly lower in smokers.

CONCLUSIONS

Smoking may not improve the natural history of ulcerative colitis. Given the health benefits of smoking cessation and the lack of clear benefit in ulcerative colitis, smoking cessation advice should be incorporated into guidance on the management of ulcerative colitis.

Patients With Inflammatory Bowel Disease Are Unaware of the Impact of Smoking on Their Disease

BACKGOUND

Tobacco is one of the most significant risk factors for inflammatory bowel disease (IBD).

GOALS

The main objective was to assess the knowledge of patients with IBD regarding the effects of tobacco on their disease. Secondary objectives were to determine the source of their knowledge, the influence of their knowledge on their intent to quit smoking, and the association between patients' characteristics and their knowledge.

STUDY

Patients with IBD completed a self-administered questionnaire on demographic data, severity of disease, and effects of tobacco on their disease.

RESULTS

In total 259 patients [182 with Crohn's disease, 77 with ulcerative colitis (UC)] participated. The prevalence of current smokers, exsmokers, and nonsmokers was 19.6%, 40.2%, and 40.2%, respectively. Patients with Crohn's disease were more aware of the effects of tobacco on their disease compared with those with UC (57.7% vs. 13.0%, P<0.0001). In informed patients, the main source of information was the gastroenterologist (56.9%). The intent to quit smoking was superior in informed patients compared with those uninformed (78.6% vs. 47.8%, P=0.046). Older patients (odds ratio=0.97, P=0.01) and patients with UC (odds ratio=0.11, P<0.0001) were less likely to be informed.

CONCLUSIONS

Only half of patients with IBD are aware of the risks of smoking associated with their disease, whereas their intent to quit smoking is directly related to their awareness. In the scope of IBD's treatment, management of smoking cessation should be undertaken in all smokers.

Predictors of Thiopurine Treatment Failure in Biologic-Naïve Ulcerative Colitis Patients

INTRODUCTION

Thiopurines (azathioprine and 6-mercaptopurine) have been used in the management of UC patients for over three decades. Nearly half of patients with UC treated with thiopurines fail to achieve remission or lose remission during treatment. Factors associated with thiopurine failure are poorly understood. The primary aim of our study was to investigate patient-related factors which are associated with thiopurine failure.

METHODS

TNF-alpha antagonist-naïve patients with histological diagnosis of UC, receiving thiopurine therapy, with follow-up data from 1 to 3 years were included in the study. Data regarding demographics, laboratory results, and disease characteristics were collected. The primary endpoint was failure of thiopurine therapy, defined as treatment with steroids, therapeutic escalation to TNF-alpha antagonist therapy, or need for surgery.

RESULTS

Of the 563 patients identified using ICD-9 codes, 78 TNF-alpha antagonist-naïve patients with a histological diagnosis of UC, receiving thiopurine treatment, were identified. Over the three-year follow-up period, 38 patients failed thiopurine treatment. On adjusted Cox regression, BMI < 25 kg/m(2) (HR 3, 95 % CI 1.55-5.83; p value = 0.001) was significantly associated with thiopurine failure. Furthermore, although not statistically significant, there was a strong trend toward thiopurine failure among patients with serum albumin level < 4 g/dL (HR 1.98, 95 % CI 0.97-4; p value = 0.06), non-smoking status (HR 2.2, 95 % CI 0.96-5.06; p value = 0.06), and higher degree of colon inflammation (HR 1.49, 95 % CI 0.96-2.32; p value = 0.08).

DISCUSSION

Our results show that low body mass index is associated with increased risk of failure of thiopurine treatment. Furthermore, there was a strong trend toward thiopurine failure among patients with low serum albumin level (<4gm/dL). These factors should be considered as markers of non-response to thiopurine monotherapy for patients with moderately severe ulcerative colitis.

Innate lymphoid cells in inflammatory bowel diseases

It is generally believed that inflammatory bowel diseases (IBD) are caused by an aberrant immune response to environmental triggers in genetically susceptible individuals. The exact contribution of the adaptive and innate immune system has not been elucidated. However, recent advances in treatments targeting key inflammatory mediators such as tumour necrosis factor highlight the crucial role of the innate immune system in IBD. Innate lymphoid cells (ILCs) have recently been identified to play an important role in immune mediated inflammatory diseases. In this review we recapitulate the current knowledge on ILCs in IBD.

Molecular Alterations of Colorectal Cancer with Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is an important etiologic factor in the development of colorectal cancer (CRC). The risk of CRC begins to increase 8 or 10 years after the diagnosis of IBD. This type of cancer is called colitis-associated CRC (CA-CRC). The molecular pathogenesis of inflammatory epithelium might play a critical role in the development of CA-CRC. Genetic alterations detected in CA-CRC such as genetic mutations, microsatellite instability, and DNA hypermethylation are also recognized in sporadic CRC; however, there are differences in the timing and frequency of molecular events between CA-CRC and sporadic CRC. Interaction between gene-environmental factors, including inflammation, lifestyle, psychological stress, and prior appendectomy, might be associated with the etiopathology of IBD. The mucosal inflammatory mediators, such as oxidant stress, free radicals, and chemokines, may cause the genetic alterations. Understanding the molecular mechanisms of CA-CRC might be important to develop clinical efficacies for patients with IBD. This review discusses the molecular characteristics of CA-CRC, especially ulcerative colitis-associated CRC, including clinical features, signaling pathways, and interactions between genetic alterations and environment involved in inflammatory carcinogenesis.

Smoking prevalence and its influence on disease course and surgery in Crohn's disease and ulcerative colitis

BACKGROUND

Smoking demonstrates divergent effects in Crohn's disease (CD) and ulcerative colitis (UC). Smoking frequency is greater in CD and deleterious to its disease course. Conversely, UC is primarily a disease of nonsmokers and ex-smokers, with reports of disease amelioration in active smoking.

AIM

To determine the prevalence of smoking and its effects on disease progression and surgery in a well-characterised cohort of inflammatory bowel diseases (IBD) patients.

METHODS

Patients with smoking data of the Sydney IBD Cohort were included. Demographic, phenotypic, medical, surgical and hospitalisation data were analysed and reported on the basis of patient smoking status.

RESULTS

1203 IBD patients were identified comprising 626 CD and 557 UC with 6725 and 6672 patient-years of follow-up, respectively. CD patients were more likely to smoke than UC patients (19.2% vs. 10.2%, P < 0.001). A history of smoking in CD was associated with an increased proportional surgery rate (45.8% vs. 37.8%, P = 0.045), requirement for IBD-related hospitalisation (P = 0.009) and incidence of peripheral arthritis (29.8% vs. 22.0%, P = 0.027). Current smokers with UC demonstrated reduced corticosteroid utilisation (24.1% vs. 37.5%, P = 0.045), yet no reduction in the rates of colectomy (3.4% vs. 6.6%, P = 0.34) or hospital admission (P = 0.25) relative to nonsmokers. Ex-smokers with UC required proportionately greater immunosuppressive (36.2% vs. 26.3%, P = 0.041) and corticosteroid (43.7% vs. 34.5%, P = 0.078) therapies compared with current and never smokers.

CONCLUSIONS

This study confirms the detrimental effects of smoking in CD, yet failed to demonstrate substantial benefit from smoking in UC. These data should encourage all patients with IBD to quit smoking.

Factors associated with poor outcomes in adults with newly diagnosed ulcerative colitis

It is a challenge to accurately identify patients with early stage ulcerative colitis (UC) who are at highest risk for a poor outcome and therefore might require salvage therapy. Several epidemiologic and clinical studies have analyzed factors associated with poor prognosis and increased risk for colectomy. We review prognostic factors for adults with newly diagnosed UC and discuss which patients might benefit from rapid and progressive therapy. Patients with poor prognoses tend to be young nonsmokers with high levels of inflammatory biomarkers, low levels of hemoglobin, and extensive disease, based on colonoscopy. We examine these risk factors in 2 hypothetical patients who have been newly diagnosed with UC.

Second peak in the distribution of age at onset of ulcerative colitis in relation to smoking cessation

BACKGROUND AND AIM

The prevalence of ulcerative colitis (UC) is increasing steadily in Japan. In Western countries, a bimodal distribution, with UC onset peaks in youth and middle age, is observed, and smoking cessation is reported as a risk factor for UC. However, there are few reports on a bimodal distribution of onset age among Japanese patients. Therefore, the distribution of onset age and factors related to late onset (i.e. onset at 50 years old or later) were investigated in UC patients in Japan.

METHODS

A questionnaire survey of UC patients was conducted to investigate the distribution of the age of onset and factors that may be related to UC onset in a Japanese university hospital.

RESULTS

Among 465 UC patients, 343 patients responded. In the distribution of onset age, a large peak was seen in patients aged 10-20s, and small peaks were seen at age 40-44 years and then in 50-60s. In addition, the onset age was older in the UC patients diagnosed in 2001 or later than in those diagnosed in 2000 or earlier. Late onset was more common among the UC patients diagnosed in 2001 or later (vs 2000 or earlier: interaction odds ratio = 4.98, 95% CI: 2.21-11.25, P < 0.01) and among former smokers (vs never-smokers: interaction odds ratio = 2.93, 95% CI: 1.40-6.14, P < 0.01) on multivariate analysis.

CONCLUSIONS

Similar to UC patients in Western countries, a bimodal distribution of onset age was also observed in Japanese UC patients, and smoking cessation may partly contribute to the increase in late-onset UC patients in recent years in Japan.

Opposing effects of smoking in ulcerative colitis and Crohn's disease may be explained by differential effects on dendritic cells

BACKGROUND

The mechanisms underlying the differential effects of cigarette smoking in patients with Crohn's disease (CD) and ulcerative colitis (UC) remain unknown. Smoking has been demonstrated to be protective in UC, whereas in CD it has been shown to be associated with a more severe course, more frequent relapses, and postoperative recurrence. Dendritic cells (DC) play a critical role in T-cell activation and differentiation. Thus, we examined the effects of in vitro exposure to cigarette smoke extract (CSE) on phenotype/function of DC obtained from patients with UC and CD.

METHODS

Sixty-eight subjects were recruited including 30 patients with CD, 19 patients with UC, and 19 healthy controls. Peripheral blood monocytes were differentiated to DC in presence of IL-4 and granulocyte-macrophage colony-stimulating factor. The influence of CSE on Mo-DC subsets, cytokine expression, and ability to drive T cell proliferation and polarization were examined.

RESULTS

CSE affected DC phenotypes including increases in class-2 major histocompatibility complex and costimulatory molecules and decreases in CXCL10 and CCL3 levels in UC compared with CD samples. Furthermore, CSE also altered DC function resulting in increasing T cell proliferation and Th1 polarization in CD, whereas it increased Foxp3+ T cells and decreased the Th1 subset in UC samples.

CONCLUSIONS

CSE modulates DC phenotype and function in patients with UC leading to increased prevalence of Foxp3+ CD4 T cells, whereas in patients with CD it skews toward Th1 subsets. Differential DC responses to CSE between CD and UC may contribute to the differential effects associated with cigarette smoking status.

Gene-gene and gene-environment interactions in ulcerative colitis

Genome-wide association studies (GWAS) have identified at least 133 ulcerative colitis (UC) associated loci. The role of genetic factors in clinical practice is not clearly defined. The relevance of genetic variants to disease pathogenesis is still uncertain because of not characterized gene-gene and gene-environment interactions. We examined the predictive value of combining the 133 UC risk loci with genetic interactions in an ongoing inflammatory bowel disease (IBD) GWAS. The Wellcome Trust Case-Control Consortium (WTCCC) IBD GWAS was used as a replication cohort. We applied logic regression (LR), a novel adaptive regression methodology, to search for high-order interactions. Exploratory genotype correlations with UC sub-phenotypes [extent of disease, need of surgery, age of onset, extra-intestinal manifestations and primary sclerosing cholangitis (PSC)] were conducted. The combination of 133 UC loci yielded good UC risk predictability [area under the curve (AUC) of 0.86]. A higher cumulative allele score predicted higher UC risk. Through LR, several lines of evidence for genetic interactions were identified and successfully replicated in the WTCCC cohort. The genetic interactions combined with the gene-smoking interaction significantly improved predictability in the model (AUC, from 0.86 to 0.89, P = 3.26E-05). Explained UC variance increased from 37 to 42 % after adding the interaction terms. A within case analysis found suggested genetic association with PSC. Our study demonstrates that the LR methodology allows the identification and replication of high-order genetic interactions in UC GWAS datasets. UC risk can be predicted by a 133 loci and improved by adding gene-gene and gene-environment interactions.

Clinical implications of ageing for the management of IBD

As the global population ages, the number of older people (≥65 years) living with IBD is expected to increase. IBD therapeutics have advanced considerably over the past few decades with the introduction of multiple steroid-sparing agents as well as numerous clinical trials that have tested new therapeutic targets. However, the current paradigms for IBD management might not be directly translatable to older patients with IBD. Age-related factors such as immunodeficiency relative to younger patients, comorbidity, polypharmacy and diminished physical reserve directly or indirectly affect the natural history of their disease. This Review highlights how these age-associated variables can affect older patients with IBD and also illustrates the multiple gaps in our current knowledge of IBD in the elderly.

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.

Review article: Ulcerative colitis, smoking and nicotine therapy

BACKGROUND

Smoking is the best-characterised environmental association of ulcerative colitis (UC). Smoking has been observed to exert protective effects on both the development and progression of UC.

AIMS

To examine the association between UC and smoking, possible pathogenic mechanisms and the potential of nicotine as a therapeutic agent in the treatment of UC.

METHODS

A literature search was conducted through MEDLINE, using the MeSH search terms 'ulcerative colitis' and 'smoking' or 'nicotine'. Relevant articles were identified through manual review. The reference lists of these articles were reviewed to include further appropriate articles.

RESULTS

Ulcerative colitis is less prevalent in smokers. Current smokers with a prior diagnosis of UC are more likely to exhibit milder disease than ex-smokers and nonsmokers. There is conflicting evidence for smokers having reduced rates of hospitalisation, colectomy and need for oral corticosteroids and immunosuppressants to manage their disease. Multiple potential active mediators in smoke may be responsible for these clinical effects, including nicotine and carbon monoxide, but the precise mechanism remains unknown. Nicotine has demonstrated variable efficacy in the induction of remission in UC when compared to placebo and conventional medicines. Despite this, the high frequency of adverse events limits its clinical significance.

CONCLUSIONS

Nicotine's application as a therapeutic treatment in ulcerative colitis is limited. Presently, it may be an option considered only in selected cases of acute ulcerative colitis refractory to conventional treatment options. This review also questions whether nicotine is the active component of smoking that modifies risk and inflammation in ulcerative colitis.

The truth about cigarette smoking and the risk of inflammatory bowel disease

The etiology of inflammatory bowel disease (IBD) is generally believed to be multifactorial in nature involving both genetic and environmental factors. Cigarette smoking has been shown through previous retrospective observational studies to be an environmental factor with both positive and negative influences in IBD. Smoking increases the risk of developing Crohn's disease (CD) but not the risk of ulcerative colitis (UC). Meanwhile smoking cessation increases the risk of a UC flare while CD patients are more likely to show a decrease in disease severity. Unfortunately, these observational studies cannot control for bias the way a randomized controlled trial can, however, they still reveal meaningful truths about smoking and IBD. The study by Higuchi et al. (1) adds to our understanding of the impact of smoking on IBD in several ways. They showed that increasing exposure to smoking is associated with an increased risk of developing CD. They also showed that the risk of UC is highest in the first 2-5 years after smoking cessation but remains elevated for > 20 years. This research also raises several new issues regarding the association between smoking and IBD, which hopefully will be answered through future well-designed observational studies.

Effects of family history on inflammatory bowel disease characteristics in Japanese patients

BACKGROUND

Although the prevalence of inflammatory bowel disease (IBD) is reported to have reached a plateau in Western countries, it is increasing in Asia. The etiology of IBD is still under investigation. We performed an epidemiological study to clarify the characteristics of IBD in Japan, focusing on patients' family history.

METHODS

We obtained clinical data on ulcerative colitis (UC) (46,114 cases) and Crohn's disease (CD) (11,305 cases) in 2007 from an electronic database maintained under the Japanese Ministry of Health, Labour and Welfare's nationwide registry system, and analyzed the differences in disease characteristics between patients with IBD who had a family history of the disease and those who did not.

RESULTS

A total of 2.7% of the patients with UC and 2.6% of those with CD had a family history. The present age and age at disease onset were lower among the patients with UC who had a family history than among those without (present age: p < 0.001; age at disease onset: p < 0.001; Mann-Whitney U-test), but no similar trend was observed in the patients with CD. Disease severity was worse among both the UC and CD patients with a family history. The clinical course of patients with UC was not affected by family history. Levels of independence in daily life were associated with family history among CD patients, whereas age was associated with levels of independence in daily life among UC patients.

CONCLUSION

Disease characteristics of IBD vary in some aspects according to the presence or absence of a family history.

Low-dose smoking resumption in ex-smokers with refractory ulcerative colitis

BACKGROUND AND AIM

Ulcerative colitis (UC) is primarily a disease of non-smokers. Ex-smokers may have a more refractory disease course and anecdotal evidence in non-controlled clinical trials have suggested that smoking resumption, or the administration of nicotine, may ameliorate signs and symptoms of UC in ex-smokers. We report outcomes of ex-smokers with refractory UC who resumed low-dose cigarette smoking.

METHODS

17 ex-smokers with refractory UC were identified. Clinical remission was defined as a disease activity index score of 0.

RESULTS

Two out of 17 patients refused the recommendation to resume smoking. Of the 15 patients who resumed smoking, the mean daily number of cigarettes was 8.6. Fourteen out of those 15 patients who resumed smoking were able to maintain prolonged clinical remission off steroids. One out of the 15 patients failed to improve and required oral steroids. Another patient was compelled to quit smoking since he became addicted. His disease flared after maintaining a prolonged remission of 3 years and he eventually underwent surgery. Three out of these 15 patients switched from cigarettes smoking to nicotine compounds and continued to maintain remission.

CONCLUSION

Resumption of low dose smoking in a selected group of ex-smokers with refractory UC may ameliorate signs and symptoms. Quality of life, medication side effects, and smoking risk factors should all be considered and discussed with patients. Smokers should be meticulously followed for compliance with "low-dose" regimen and all associated smoking risks.

Gene-environment interactions in inflammatory bowel disease: microbiota and genes

A recent research workshop gave an update on the genetics of the inflammatory bowel diseases (IBD), Crohn's disease and ulcerative colitis. This mini-review summarises the updates of the gene-environmental interactions, especially those outlining the contribution of the gut microbiota to the pathogenesis of IBD.

Cigarette smoke extract (CSE) delays NOD2 expression and affects NOD2/RIPK2 interactions in intestinal epithelial cells

BACKGROUND

Genetic and environmental factors influence susceptibility to Crohn's disease (CD): NOD2 is the strongest individual genetic determinant and smoking the best-characterised environmental factor. Carriage of NOD2 mutations predispose to small-intestinal, stricturing CD, a phenotype also associated with smoking. We hypothesised that cigarette smoke extract (CSE) altered NOD2 expression and function in intestinal epithelial cells.

METHODS AND FINDINGS

Intestinal epithelial cell-lines (SW480, HT29, HCT116) were stimulated with CSE and nicotine (to mimic smoking) ±TNFα (to mimic inflammation). NOD2 expression was measured by qRT-PCR and western blotting; NOD2-RIPK2 interactions by co-immunoprecipitation (CoIP); nuclear NFκB-p65 by ELISA; NFκB activity by luciferase reporter assays and chemokines (CCL20, IL8) in culture supernatants by ELISA. In SW480 and HT29 cells the TNFα-induced NOD2 expression at 4 hours was reduced by CSE (p = 0.0226), a response that was dose-dependent (p = 0.003) and time-dependent (p = 0.0004). Similar effects of CSE on NOD2 expression were seen in cultured ileal biopsies from healthy individuals. In SW480 cells CSE reduced TNFα-induced NFκB-p65 translocation at 15 minutes post-stimulation, upstream of NOD2. Levels of the NOD2-RIPK2 complex were no different at 8 hours post-stimulation with combinations of CSE, nicotine and TNFα, but at 18 hours it was increased in cells stimulated with TNFα+CSE but decreased with TNFα alone (p = 0.0330); CSE reduced TNFα-induced NFκB activity (p = 0.0014) at the same time-point. At 24 hours, basal CCL20 and IL8 (p<0.001 for both) and TNFα-induced CCL20 (p = 0.0330) production were decreased by CSE. CSE also reduced NOD2 expression, CCL20 and IL8 production seen with MDP-stimulation of SW480 cells pre-treated with combinations of TNFα and CSE.

CONCLUSIONS

CSE delayed TNFα-induced NOD2 mRNA expression and was associated with abnormal NOD2/RIPK2 interaction, reduced NFκB activity and decreased chemokine production. These effects may be involved in the pathogenesis of small-intestinal CD and may have wider implications for the effects of smoking in NOD2-mediated responses.

Functional analysis of agalactosyl IgG in inflammatory bowel disease patients

BACKGROUND

Agalactosyl immunoglobulin (Ig) G is increased in inflammatory bowel disease (IBD) similarly to rheumatoid arthritis (RA). The lectin complement pathway is shown to be activated through association of agalactosyl IgG with mannan-binding lectin (MBL) in RA. Functional changes of IgG agalactosylation in IBD, however, have not yet been clarified.

METHODS

The ratio of the agalactosyl/non-agalactosyl fraction in fucosylated IgG oligosaccharides (G0F/G2F) and serum MBL levels were analyzed in 59 patients with Crohn's disease (CD), 64 ulcerative colitis (UC), and 39 healthy volunteers (HV). The MBL levels associated with serum IgG were analyzed by enzyme-linked immunosorbent assay. MBL expression in the intestinal mucosa was analyzed by immunohistochemistry. Phagocytosis of sheep red blood cells (SRBC) reacted with either an agalactosyl or non-agalactosyl SRBC-specific IgG antibody was determined by flow cytometry.

RESULTS

The serum MBL levels were not significantly different among CD, UC, or HV. In patients with CD, the serum MBL levels were negatively correlated with the Crohn's Disease Activity Index (CDAI). The levels of MBL associated with agalactosyl IgG were not different from those associated with non-agalactosyl IgG. Immunoreactivity to MBL was less in the inflamed mucosa compared with the noninflamed mucosa. Phagocytic activity of SRBC was significantly higher in the presence of agalactosyl IgG compared to non-agalactosyl IgG.

CONCLUSIONS

Agalactosyl IgG oligosaccharides enhanced antibody-dependent phagocytosis in vitro but did not activate the lectin complement pathway. Oligosaccharide alterations of IgG are not only a marker of IBD but also functionally modulate the immune function of IBD.

Cyclooxygenase-2 (COX-2) polymorphisms and risk of inflammatory bowel disease in a Scottish and Danish case-control study

BACKGROUND

Inflammatory bowel diseases (IBDs) are a result of interactions between luminal pathogens and the intestinal immune response. Cyclooxygenase-2 (COX-2) plays a key role in the regulation of the inflammatory response upon stimulation by luminal pathogens via Toll-like receptors.

METHODS

Genotypes of the COX-2/PTGS2/PGHS2 A-1195G (rs689466), G-765C (rs20417), and T8473C (rs5275) polymorphisms were assessed in a Scottish and Danish case-control study including 732 Crohn's disease (CD) cases, 973 ulcerative colitis (UC) cases, and 1157 healthy controls using logistic regression.

RESULTS

Carriers of the COX-2 A-1195G variant allele had increased risk of UC (odds ratio [OR], 95% confidence interval [CI] = 1.25 [1.02-1.54], P = 0.03) and of both UC and IBD among never smokers (OR [95% CI] = 1.47 [1.11-1.96], P = 0.01 and OR [95% CI] = 1.37 [1.06-1.77], P = 0.02, respectively). Furthermore, this variant genotype was associated with increased risk of diagnosis of UC before age 40 years and with extensive UC (OR [95% CI] = 1.34 [1.11-1.62], P = 0.002 and OR [95% CI] = 1.32 [1.03-1.69], P = 0.03, respectively).

CONCLUSIONS

COX-2 A-1195G polymorphism was associated with the risk of UC, especially among never-smokers, suggesting that low activity of COX-2 may predispose to UC. Our results suggest that inclusion of smoking status may be essential for the evaluation of the role of genetic predisposition to IBD.

Genetics of ulcerative colitis

Ulcerative colitis (UC) and Crohn's disease (CD) are related polygenic inflammatory bowel diseases (IBDs), with distinct and overlapping susceptibility loci. Recently, hypothesis-free genome-wide association (GWA) studies have revolutionized the field of complex disease genetics. Substantial advances have been achieved in defining the genetic architecture of IBD. To date, over 60 published IBD susceptibility loci have been discovered and replicated, of which approximately a third are associated with both UC and CD, although 21 are specific to UC and 23 to CD. In CD, the breakthrough identification of NOD2 as a susceptibility gene was followed by a rapid phase of gene discovery from GWA studies between 2006 and 2008. Progress in UC was slower; however, by initially testing hits for CD in UC, and later scanning larger UC cohorts, significant new loci for UC have been discovered, with exciting novel insights into disease pathogenesis. Notably, genes implicated in mucosal barrier function (ECM1, CDH1, HNF4α, and laminin B1) confer risk of UC; furthermore, E-cadherin is the first genetic correlation between colorectal cancer and UC. Impaired IL10 signaling has reemerged as a key pathway in intestinal inflammation, and is perhaps the most amenable to therapeutic intervention in UC. Collaborative international efforts with large meta-analyses of GWA studies and replication will yield many new UC genes. Furthermore, a large effort is required to characterize the loci found. Fine-mapping, deep resequencing, and functional studies will be critical to translating these gene discoveries into pathogenic insights, and ultimately into clinical insights and novel therapeutics.

Growth of M. avium subspecies paratuberculosis in culture is enhanced by nicotinic acid, nicotinamide, and α and β nicotinamide adenine dinucleotide

BACKGROUND

Without known mechanisms of action, Crohn's disease is exacerbated, and ulcerative colitis is improved, by the use of tobacco. Mycobacterium avium subspecies paratuberculosis (MAP) may be zoonotic. We hypothesized that tobacco components might alter the growth kinetics of MAP, explaining these divergent clinical observations.

METHODS

The effect of nicotine, nicotinic acid, nicotinamide and α and β nicotinamide adenine dinucleotide (α and β NAD) were studied on eight strains of three mycobacterial species (MAP, M. avium and M. tb. complex). Data are obtained as "cumulative growth index," (cGI) and presented as "percent increase in cumulative GI" (% + ΔcGI).

RESULTS

Nicotinic acid enhances the two human MAP isolates (Dominic; 225% + ΔcGI and UCF-4; 92% + ΔcGI) and M. avium (ATCC 25291; 175% + ΔcGI). Nicotinamide (at 6.4 µg/ml) enhances the human MAP isolates (Dominic; 156% + ΔcGI and UCF-4; 79% + ΔcGI) and M. avium (ATCC 25291; 144% + ΔcGI.) Both α and β NAD enhance Dominic; (135 and 150 % + ΔcGI) and UCF-4; (81 and 79% + ΔcGI). At the doses tested, nicotine has no effect on any strain studied.

CONCLUSIONS

We show enhancement of MAP growth by nicotinic acid, one of ≥4,000 tobacco-related molecules, its amide, nicotinamide and α and β NAD. Pure nicotine has no enhancing effect at the doses studies.

Patients with late-adult-onset ulcerative colitis have better outcomes than those with early onset disease

BACKGROUND & AIMS

The influence of age on the presentation, clinical course, and therapeutic response of patients with adult-onset ulcerative colitis (UC) is understudied. Given potential age-related differences in risk factors and immune function, we sought to determine if disease behavior or clinical outcomes differed between patients diagnosed with UC in later versus earlier stages of adulthood.

METHODS

We performed a retrospective cohort study of 295 patients with UC seen at a tertiary care center from 2001 to 2008. Adult subjects newly diagnosed with UC between the ages of 18 and 30 years were defined as early onset, those newly diagnosed at age 50 or older were defined as late onset. The 2 groups were analyzed for differences in medication use and clinical end points, including disease extent, severity at the time of diagnosis, and steroid-free clinical remission at 1 year after disease onset.

RESULTS

Disease extent and symptom severity were similar between groups at the time of diagnosis. One year after diagnosis, more patients in the late-onset group achieved steroid-free clinical remission (64% vs 49%; P = .01). Among those who required systemic steroid therapy, more late-onset patients achieved steroid-free remission by 1 year (50% vs 32%; P = .01). Former smoking status was a more common risk factor in the late-onset cohort (P < .001), whereas more early onset patients had a positive family history (P = .008).

CONCLUSIONS

Patients with early and late-adult-onset UC have similar initial clinical presentations, but differ in disease risk factors. Late-onset patients have better responses to therapy 1 year after diagnosis.

Early azathioprine/biological therapy is associated with decreased risk for first surgery and delays time to surgery but not reoperation in both smokers and nonsmokers with Crohn's disease, while smoking decreases the risk of colectomy in ulcerative colitis

BACKGROUND/AIMS

Smoking may alter the natural course of Crohn's disease (CD). Smokers are more likely to develop complications, relapses and have a greater risk for surgery. In contrast, in ulcerative colitis (UC), smoking might improve the disease course. Our aim was to assess the combined effect of disease phenotype, smoking, and immunomodulator [azathioprine (AZA), AZA/biological] treatment on the risk of intestinal resection/reoperation in CD and colectomy in UC.

PATIENTS/METHODS

Six hundred and eighty-one inflammatory bowel disease patients were analyzed (CD: 340, male/female: 155/185, duration: 9.4+/-7.5 years; UC: 341, male/female: 174/164, duration: 11.5+/-9.7 years). Patients were interviewed on their smoking habits at the time of diagnosis and during the regular follow-up visits. Medical records were retrospectively analyzed.

RESULTS

Smoking was present in 45.5% in CD and 15.8% in UC. CD patients who underwent at least one bowel resection comprised 46.5%. In an univariate analysis, disease location, behavior, AZA, or AZA/biological use before surgery [odds ratio (OR): 0.26 and 0.22, P<0.001] and smoking (OR: 1.61, P = 0.03) were associated with risk for first surgery. Smoking, AZA, or AZA/biological (P<0.001) use before first surgery and disease behavior were independently associated with risk for surgery in a proportional Cox-regression analysis. Perianal disease (OR: 3.2, P = 0.001) and frequent relapses (OR: 4.8, P<0.001) but not smoking, AZA, or AZA/biological use after first surgery were predictive for reoperation. In UC, the rate of colectomy was 5.6%. Disease location (P = 0.001) and smoking status (P = 0.02) were independently associated with risk for colectomy in a proportional Cox-regression analysis.

CONCLUSION

Our data suggest that early AZA/biological therapy reduces the risk for first operation but not reoperation in CD, in both smokers and nonsmokers. In contrast, smoking was associated with a decreased need for colectomy in UC.

Roles of double-balloon endoscopy in the diagnosis and treatment of Crohn's disease: a multicenter experience

BACKGROUND

Double-balloon endoscopy (DBE) examinations are not yet widely accepted as routine procedures for examining the small bowel of patients with Crohn's disease (CD).

AIM

To evaluate the feasibility and usefulness of DBE for CD in tertiary-care hospitals.

METHODS

Between July 2004 and September 2008, 1444 DBE procedures were performed for 704 patients in 6 tertiary-care hospitals. Patient profile, indication, diagnosis and treatment of DBE were evaluated using a multicenter database.

RESULTS

DBE examinations were most frequently performed in 75 patients with CD, corresponding to 10.5% of all the patients examined by DBE. Fifty patients were diagnosed with CD before DBE, while DBE was performed for the diagnosis of 25 new CD patients. Small bowel lesions were often detected even when the terminal ileum was not involved. In the 75 patients, 21 patients were asymptomatic at the time of DBE examinations. Active inflammatory lesions were detected in 51.2% of the CD patients, and were even detected in 33.3% of the asymptomatic CD patients. The treatment was altered in 53.3% of the CD patients after the DBE evaluation. No severe complications were experienced.

CONCLUSIONS

DBE procedures can be safely performed in patients with CD and should be considered for the precise evaluation of and to determine the treatment strategy for CD.

Active and passive smoking behaviour and cessation plans of patients with Crohn's disease and ulcerative colitis

BACKGROUND

Smoking is a remarkable risk factor in inflammatory bowel disease (IBD), with negative effects on Crohn's disease (CD) and positive effects on ulcerative colitis (UC). This makes different changes in smoking behaviour after diagnosis between CD and UC likely. Changes in active smoking, cessation plans and passive smoking were studied in IBD patients.

METHODS

820 IBD patients were sent a questionnaire on active and passive smoking, and cessation plans. A total of 675 (82%) patients (380 CD and 295 UC) responded.

RESULTS

More ever smoking UC patients stopped smoking before diagnosis than CD patients (63% vs 22%; p<0.001), resulting in 30% former smokers at diagnosis in UC and 13% in CD (p<0.001). The smoking cessation rates at and after diagnosis are equal between CD and UC. Half of the CD patients stopped smoking after diagnosis leading to less present smokers in CD than in a control population (26% (95% confidence interval: 21.1%-29.9%) vs 33%). For both CD (22% vs 35%; p=0.044) and UC (24% vs 53%; p=0.024) continuing smokers after diagnosis were less often higher educated than quitters. Cessation plans (89%), passive smoking in childhood and present passive smoking were not different between CD and UC patients.

CONCLUSION

There are no differences in changes in smoking behaviour at and after diagnosis between CD and UC patients, suggesting a lack of knowledge in these patients about the link between their disease and smoking behaviour. However, CD patients seem less refractory to smoking cessation than the general population. Therefore it is worthwhile putting energy in helping CD patients stop smoking.

Ulcerative colitis in a Southern European country: a national perspective

BACKGROUND

The incidence, prevalence, and even the clinical behavior of ulcerative colitis (UC) are highly variable in different world regions. In previous studies, Portugal was reported as having a milder clinical behavior. The aim of this study was to apply the Montreal Classification in a large group of UC Portuguese patients in order to describe their clinical characteristics and evaluate variables potentially useful for outcome prediction.

METHODS

A cross-sectional study based on data collected from a nationwide online registry was undertaken.

RESULTS

In all, 2863 patients with UC were included. Twenty-one percent had ulcerative proctitis, 52% left-sided colitis, and 28% extensive colitis. Sixty percent of patients had taken steroids, 14% immunosuppressors, 1% biologicals, and 4.5% were submitted to surgery. Patients with extensive colitis had more severe activity, needing more steroids, immunosuppressors, and surgery. At the time of diagnosis 61% were less than 40 years old and 5% less than 16. Younger patients also had a more aggressive initial course. Thirty-eight percent of patients had only taken salicylates during the disease course and were characterized by a lower incidence of systemic symptoms at presentation (3.8% versus 8.8%, P < 0.001), fewer extraintestinal manifestations (7.7% versus 24.0%, P < 0.001), and a higher prevalence of proctitis (32.1% versus 10.0%).

CONCLUSIONS

A more aggressive phenotype was found in extensive colitis and in the initial course of younger patients, with an increased need for steroids and immunosuppressors. In addition, a significant percentage of patients, particularly with proctitis, showed a milder clinical evolution and were maintained in remission only with salicylates.

Effects of active and passive smoking on disease course of Crohn's disease and ulcerative colitis

BACKGROUND

Smoking is a remarkable risk factor for inflammatory bowel disease (IBD), aggravating Crohn's disease (CD) while having beneficial effects on ulcerative colitis (UC). We studied the effects of active and passive smoking in Dutch IBD patients.

METHODS

A questionnaire focusing on cigarette smoke exposure was sent to 820 IBD patients. Returned questionnaires were incorporated into a retrospective chart review, containing details about disease behavior and received therapy.

RESULTS

In all, 675 IBD patients (380 [56%] CD and 295 [44%] UC) responded. At diagnosis there were 52% smokers in CD, 41% in the general population, and 28% in UC. The number of present smokers in CD is lower than in the general population (26% versus 35%). No detrimental effects of active smoking on CD were observed, but passive smokers needed immunosuppressants and infliximab more frequently than nonpassive smokers. Active smoking had beneficial effects on UC, indicated by reduced rates of colectomy, primary sclerosing cholangitis, and backwash-ileitis in active smokers compared to never smokers, and higher daily cigarette dose correlated with less extensive colitis and a lower need for therapy. Furthermore, smoking cessation after diagnosis was detrimental for UC patients, indicated by increased needs for steroids and hospitalizations for patients that stopped smoking after compared to before the diagnosis.

CONCLUSIONS

Active smoking is a risk factor for CD, but does not affect the outcome; passive smoking is detrimental for the outcome of CD patients. In UC, active smoking shows dose-dependent beneficial effects. Our data suggest that passive smoking is a novel risk factor for CD.

Dysregulation of human beta-defensin-2 protein in inflammatory bowel disease

Background

Human β-defensin-2 (HBD2) is an antimicrobial peptide implicated in the pathogenesis of inflammatory bowel disease (IBD). Low copy number and concomitant low mRNA expression of the HBD2 gene have been implicated in susceptibility to colonic Crohn's Disease (CD). We investigated the colonic distribution of HBD2 mRNA expression, and the contributions of genetic and environmental factors on HBD2 protein production.

Methodology/Principal Findings

We examined HBD2 mRNA expression at three colonic locations by microarray analysis of biopsies from 151 patients (53 CD, 67 ulcerative colitis [UC], 31 controls). We investigated environmental and genetic influences on HBD2 protein production using ex vivo cultured sigmoid colon biopsies from 69 patients (22 CD, 26 UC, 21 controls) stimulated with lipopolysaccharide (LPS) and/or nicotine for 24 hours. HBD2 and cytokines were measured in culture supernatants. Using DNA samples from these patients, regions in the HBD2 gene promoter were sequenced for NF-κB binding-sites and HBD2 gene copy number was determined. HBD2 mRNA expression was highest in inflamed (vs. uninflamed p = 0.0122) ascending colon in CD and in inflamed (vs. uninflamed p<0.0001) sigmoid colon in UC. HBD2 protein production was increased in inflamed UC biopsies (p = 0.0078). There was no difference in HBD2 protein production from unstimulated biopsies of CD, UC and controls. LPS-induced HBD2 production was significantly increased in CD (p = 0.0375) but not UC (p = 0.2017); this LPS-induced response was augmented by nicotine in UC (p = 0.0308) but not CD (p = 0.6872). Nicotine alone did not affect HBD2 production. HBD2 production correlated with IL8 production in UC (p<0.001) and with IL10 in CD (p<0.05). Variations in the HBD2 promoter and HBD2 gene copy number did not affect HBD2 production.

Significance/Conclusions

Colonic HBD2 was dysregulated at mRNA and protein level in IBD. Inflammatory status and stimulus but not germline variations influenced these changes.