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

Autophagy: A potential target for natural products in the treatment of ulcerative colitis

Ulcerative colitis (UC) is a chronic inflammatory bowel disease primarily affecting the mucosa of the colon and rectum. UC is characterized by recurrent episodes, often necessitating lifelong medication use, imposing a significant burden on patients. Current conventional and advanced treatments for UC have the disadvantages of insufficient efficiency, susceptibility to drug resistance, and notable adverse effects. Therefore, developing effective and safe drugs has become an urgent need. Autophagy is an intracellular degradation process that plays an important role in intestinal homeostasis. Emerging evidence suggests that aberrant autophagy is involved in the development of UC, and modulating autophagy can effectively alleviate experimental colitis. A growing number of studies have established that autophagy can interplay with endoplasmic reticulum stress, gut microbiota, apoptosis, and the NLRP3 inflammasome, all of which contribute to the pathogenesis of UC. In addition, a variety of intestinal epithelial cells, including absorptive cells, goblet cells, and Paneth cells, as well as other cell types like neutrophils, antigen-presenting cells, and stem cells in the gut, mediate the development of UC through autophagy. To date, many studies have found that natural products hold the potential to exert therapeutic effects on UC by regulating autophagy. This review focuses on the possible effects and pharmacological mechanisms of natural products to alleviate UC with autophagy as a potential target in recent years, aiming to provide a basis for new drug development.

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.

Association Between Smoking Status and the Efficacy and Safety of Tofacitinib in Patients with Ulcerative Colitis

Background

Tofacitinib is an oral Janus kinase inhibitor for the treatment of ulcerative colitis (UC). This analysis assessed the impact of cigarette smoking on tofacitinib efficacy and safety in the UC clinical program.

Methods

Efficacy endpoints and adverse events (AEs) were evaluated by smoking status (ever smokers [current and ex-smokers] and never smokers) in the phase (P)2 induction study (baseline demographics and safety only), P3 studies (OCTAVE Induction 1&2, OCTAVE Sustain, OCTAVE Open), and P3/4b RIVETING study.

Results

This post hoc analysis included 1156 patients (ever smokers, n = 416 [36.0%; current smokers, n = 59 (5.1%); ex-smokers, n = 357 (30.9%)]; never smokers, n = 740 [64.0%]; median [range] treatment duration 654 [1-2712] and 615.5 [1-2850] days, respectively). Similar proportions of ever smokers and never smokers achieved efficacy endpoints. AEs were reported in 88.7% of ever smokers and 83.8% of never smokers. Overall, 60.6% of ever smokers had an infection (serious infections, 5.5%; herpes zoster [nonserious and serious], 10.8%; Clostridioides difficile infection, 12.0%; lower respiratory tract infection, 19.5%: corresponding values among never smokers were 53.1%, 3.9%, 6.8%, 8.5%, and 11.4%). Major adverse cardiovascular events were reported in 1.0% of ever smokers and 0.7% of never smokers and thromboembolism events (venous and arterial) in 1.0% of ever smokers and 0.9% never smokers. Deaths, malignancies (excluding non-melanoma skin cancer [NMSC]), and NMSC occurred infrequently in ever smokers (0.5%, 2.5%, and 3.7%, respectively) and never smokers (0.1%, 1.5%, and 1.0%, respectively). Colorectal cancer was reported in 0.6% of never smokers; no cases occurred in ever smokers.

Conclusions

Efficacy and safety of tofacitinib were generally similar in ever smokers and never smokers. Overall, serious AEs and, as expected, infections were more frequent in ever smokers versus never smokers. This may inform treatment selection and monitoring strategies.

ClinicalTrialsgov

NCT00787202;NCT01465763;NCT01458951;NCT01458574;NCT01470612;NCT03281304.

Evidence-based pathogenesis and treatment of ulcerative colitis: A causal role for colonic epithelial hydrogen peroxide

In this comprehensive evidence-based analysis of ulcerative colitis (UC), a causal role is identified for colonic epithelial hydrogen peroxide (H₂O₂) in both the pathogenesis and relapse of this debilitating inflammatory bowel disease. Studies have shown that H₂O₂ production is significantly increased in the non-inflamed colonic epithelium of individuals with UC. H₂O₂ is a powerful neutrophilic chemotactic agent that can diffuse through colonic epithelial cell membranes creating an interstitial chemotactic molecular “trail” that attracts adjacent intravascular neutrophils into the colonic epithelium leading to mucosal inflammation and UC. A novel therapy aimed at removing the inappropriate H₂O₂ mediated chemotactic signal has been highly effective in achieving complete histologic resolution of colitis in patients experiencing refractory disease with at least one (biopsy-proven) histologic remission lasting 14 years to date. The evidence implies that therapeutic intervention to prevent the re-establishment of a pathologic H₂O₂ mediated chemotactic signaling gradient will indefinitely preclude neutrophilic migration into the colonic epithelium constituting a functional cure for this disease. Cumulative data indicate that individuals with UC have normal immune systems and current treatment guidelines calling for the suppression of the immune response based on the belief that UC is caused by an underlying immune dysfunction are not supported by the evidence and may cause serious adverse effects. It is the aim of this paper to present experimental and clinical evidence that identifies H₂O₂ produced by the colonic epithelium as the causal agent in the pathogenesis of UC. A detailed explanation of a novel therapeutic intervention to normalize colonic H₂O₂, its rationale, components, and formulation is also provided.

Medical treatment of pouchitis: a guide for the clinician

Pouchitis is the most common complication in patients who have undergone restorative proctocolectomy with ileal pouch-anal anastomosis (IPAA). Up to 81% of IPAA patients experience pouchitis, with 40% of patients presenting within the first year of surgery. Common risk factors include genetic mutations, extensive colitis, rheumatologic disorders, and primary sclerosing cholangitis. Currently, there are no medications with approved indications for pouchitis. As such, the conventional treatment of pouchitis is entirely off-label. This paper is intended to be a practical and up-to-date review of available therapies used for the management of pouchitis. The mainstay of treatment for acute pouchitis remains antibiotics, but newer therapeutics have also shown promise in the treatment of chronic pouchitis. Common lifestyle considerations that may play a role in pouchitis are also reviewed.

PLAIN LANGUAGE SUMMARY

Medical treatment of pouchitis: a guide for the clinician The ileal pouch-anal anastomosis ("pouch") is the most common way patients who require surgery to remove their colon are able to avoid a permanent ileostomy ("ostomy"). This pouch, created from the small intestines, serves as a reservoir to hold stool. The most common complication after pouch surgery is pouchitis. Pouchitis symptoms include more frequent bowel movements, urgency to defecate, blood in the stool, incontinence, and abdominal pain. This paper is intended to be a practical review of available therapies including medications and lifestyle changes that can be considered for the management of acute pouchitis, chronic pouchitis, and cuffitis.

Hydrogen sulfide toxicity in the gut environment: Meta-analysis of sulfate-reducing and lactic acid bacteria in inflammatory processes

BACKGROUND

Hydrogen sulfide is the final product of sulfate-reducing bacteria metabolism. Its high concentration in the gut can affect adversely bowel environment and intestinal microbiota by toxicity and pH lowering.

AIM OF REVIEW

The aim of the review was to give observations related to the properties of bacterial communities inhabiting the gut, with the emphasis on sulfate-reducing bacteria and lactic acid bacteria.

KEY SCIENTIFIC CONCEPTS OF REVIEW

The conduction of meta-analysis was another goal, since it gave statistical observation of the relevant studies. The review literature consisted of more than 160 studies, published from 1945 to 2019. Meta-analysis included 16 studies and they were chosen from the Web of Science database. The systematic review gave important information about the development of gut inflammation, with emphasis on sulfate-reducing and lactic acid bacteria. Oppositely from sulfate-reducing bacteria, probiotic properties of lactic acid bacteria are effective inhibitors against inflammatory bowel disease development, including ulcerative colitis. These facts were confirmed by the conducted meta-analysis. The results and observations gained from the systematic review represent the emphasized importance of gut microbiota for bowel inflammation. On the other side, it should be stated that more studies in the future will provide even better confirmations.

Safety and effectiveness of adalimumab in the treatment of ulcerative colitis: results from a large-scale, prospective, multicenter, observational study

Background/Aims

Adalimumab has been shown to induce and maintain clinical remission in patients with moderate to severe ulcerative colitis (UC). However, no large-scale population-based studies have been performed in Japan. This study was conducted to evaluate the safety and effectiveness of adalimumab in clinical practice in Japanese patients with UC.

Methods

In this 52-week, prospective, multicenter, single-cohort, noninterventional, observational, postmarketing surveillance study, patients with moderate to severe UC received an initial subcutaneous injection of adalimumab 160 mg, followed by 80 mg at 2 weeks, and then 40 mg every other week. Safety assessments were the incidence of adverse drug reactions (ADRs) and serious ADRs. Effectiveness assessments were clinical remission, corticosteroid-free remission, mucosal healing, and change in C-reactive protein (CRP) levels from baseline.

Results

Of 1,593 registered patients, 1,523 (male, 57.6%; mean age, 41.8 years) and 1,241 patients were included in the safety and effectiveness populations, respectively. ADRs were reported in 18.1% and serious ADRs in 4.9% of patients. Clinical remission was achieved in 49.7% of patients at week 4, increasing to 74.4% at week 52. Corticosteroid-free remission rates increased over time, from 10.4% at week 4 to 53.1% at week 52. More than 60% of patients demonstrated mucosal healing at weeks 24 and 52. Mean CRP levels (mg/dL) decreased from 1.2 at baseline to 0.6 at week 4 and 0.3 at week 52.

Conclusions

This large real-world study confirmed the safety and effectiveness of adalimumab in patients with UC in Japan. No new safety concerns were identified.

Systematic review with meta-analysis: a history of smoking is not associated with a higher risk of pouchitis

BACKGROUND

Ileal pouch-anal anastomosis is a common surgical procedure in patients with an initial diagnosis of ulcerative colitis or indeterminate colitis. Tobacco smoking has been associated with protection from onset of ulcerative colitis. Smoking has been reported to be both a protective factor and a risk factor for the development of pouchitis.

AIM

To examine the influence of smoking on the risk of pouchitis.

METHODS

We identified 15 studies evaluating smoking as a risk factor for developing pouchitis in ulcerative colitis or indeterminate colitis patients with a history of ileal pouch-anal anastomosis in a systematic search performed from inception through May 4, 2020. A meta-analysis was then performed using a random-effects model to generate risk ratios (RR) and 95% confidence intervals (CI).

RESULTS

A history of smoking compared with never smoking was not associated with an increased risk of developing pouchitis (RR = 0.94, 95% CI 0.76-1.18, I²  = 73.7%). There was also no significant risk of pouchitis when comparing current smokers vs nonsmokers (RR = 0.93, 95% CI 0.70-1.24, I²  = 78.5%) and former smokers vs nonsmokers (RR = 0.96, 95% CI 0.74-1.23, I²  = 78.5%).

CONCLUSIONS

Smoking, past or present, is not associated with an increased risk for the development of pouchitis in patients with ulcerative colitis or indeterminate colitis.

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.

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.

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.

Smoking and the Risk of Pouchitis in Ulcerative Colitis Patients With Ileal Pouch-Anal Anastomosis

BACKGROUND

Ulcerative colitis (UC) patients who undergo proctocolectomy with ileal pouch-anal anastomosis (IPAA) may develop pouchitis, a poorly understood inflammatory condition. There is controversy over whether tobacco use can protect against pouchitis. We undertook this investigation to further evaluate whether smoking reduces the risk of developing pouchitis and to determine whether other previously associated clinical factors change the risk for pouchitis.

METHODS

We performed a retrospective analysis using a consented inflammatory bowel disease (IBD) natural history registry between the years 1995-2015 from a single tertiary care referral center. Demographic data, medical history, surgical information, medication use, laboratory data, and smoking history were abstracted. Former smokers had quit for at least 1 year. The primary end point was development of pouchitis.

RESULTS

Of the 353 UC patients with IPAA in this study, 126 (35.6%) developed pouchitis. Prior tobacco use (P < 0.0001) was more common in patients who developed pouchitis. Former and active smokers were more likely to develop pouchitis compared with those without a history of tobacco use (63.4% vs 27.3% respectively, P < 0.001). There was no significant difference in active smoking rate between those without pouchitis and the group that did develop pouchitis. Multivariate analysis demonstrated that the only independent risk factor associated with pouchitis was a history of tobacco use.

CONCLUSIONS

These results suggest that smoking cessation may increase the likelihood of developing pouchitis in tobacco users with UC and IPAA, but active smoking does not seem to be more effective in preventing this condition.

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.

Hospitalizations for Acute Myocardial Infarction Are Decreased Among Patients with Inflammatory Bowel Disease Using a Nationwide Inpatient Database

BACKGROUND

Questions remain regarding the true prevalence of cardiovascular events such as myocardial infarction (MI) among patients with inflammatory bowel disease (IBD). Using the Nationwide Inpatient Sample (NIS), we aimed to compare the proportion of hospitalizations for acute MI among patients with IBD with that of the general population.

METHODS

This study used data from years 2000 to 2011 in Nationwide Inpatient Sample, the largest publicly available all-payer inpatient database in the United States. International Classification of Diseases, Ninth Revision, Clinical Modification discharge codes were used to identify adult patients with discharge diagnoses of IBD (ulcerative colitis or Crohn's disease), acute MI, and multiple comorbid risk factors for cardiovascular disease. The independent effect of a diagnosis of IBD on risk of acute MI was examined using a multivariable logistic regression model controlling for multiple confounders. Data were analyzed using SAS survey procedures and weighted to reflect national estimates.

RESULTS

We identified 567,438 hospitalizations among patients with IBD and 78,121,000 hospitalizations among the general population. Patients with IBD were less likely to be hospitalized for acute MI than patients in the general population (1.3% versus 3.1%, P < 0.001). In adjusted analyses, the odds of hospitalization for acute MI among patients with IBD were decreased when compared with the general population (odds ratio, 0.51; 95% confidence interval, 0.50-0.52).

CONCLUSIONS

Despite prior reports of a potentially increased risk of acute MI among patients with IBD, in a nationwide inpatient database, lower rates of acute MI were demonstrated in the IBD population when compared with the general population.

Reactive oxygen species in organ-specific autoimmunity

Reactive oxygen species (ROS) have been extensively studied in the induction of inflammation and tissue damage, especially as it relates to aging. In more recent years, ROS have been implicated in the pathogenesis of autoimmune diseases. Here, ROS accumulation leads to apoptosis and autoantigen structural changes that result in novel specificities. ROS have been implicated not only in the initiation of the autoimmune response but also in its amplification and spreading to novel epitopes, through the unmasking of cryptic determinants. This review will examine the contribution of ROS to the pathogenesis of four organ specific autoimmune diseases (Hashimoto thyroiditis, inflammatory bowel disease, multiple sclerosis, and vitiligo), and compare it to that of a better characterized systemic autoimmune disease (rheumatoid arthritis). It will also discuss tobacco smoking as an environmental factor endowed with both pro-oxidant and anti-oxidant properties, thus capable of differentially modulating the autoimmune response.

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.

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.

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

BACKGROUND AND AIMS

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Epidemiology and risk factors for IBD

IBD, comprising Crohn's disease and ulcerative colitis, is a chronic immunologically mediated disease at the intersection of complex interactions between genetics, environment and gut microbiota. Established high-prevalence populations of IBD in North America and Europe experienced the steepest increase in incidence towards the second half of the twentieth century. Furthermore, populations previously considered 'low risk' (such as in Japan and India) are witnessing an increase in incidence. Potentially relevant environmental influences span the spectrum of life from mode of childbirth and early-life exposures (including breastfeeding and antibiotic exposure in infancy) to exposures later on in adulthood (including smoking, major life stressors, diet and lifestyle). Data support an association between smoking and Crohn's disease whereas smoking cessation, but not current smoking, is associated with an increased risk of ulcerative colitis. Dietary fibre (particularly fruits and vegetables), saturated fats, depression and impaired sleep, and low vitamin D levels have all been associated with incident IBD. Interventional studies assessing the effects of modifying these risk factors on natural history and patient outcomes are an important unmet need. In this Review, the changing epidemiology of IBD, mechanisms behind various environmental associations and interventional studies to modify risk factors and disease course are discussed.

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.

Connections of nicotine to cancer

This Opinion article discusses emerging evidence of direct contributions of nicotine to cancer onset and growth. The list of cancers reportedly connected to nicotine is expanding and presently includes small-cell and non-small-cell lung carcinomas, as well as head and neck, gastric, pancreatic, gallbladder, liver, colon, breast, cervical, urinary bladder and kidney cancers. The mutagenic and tumour-promoting activities of nicotine may result from its ability to damage the genome, disrupt cellular metabolic processes, and facilitate growth and spreading of transformed cells. The nicotinic acetylcholine receptors (nAChRs), which are activated by nicotine, can activate several signalling pathways that can have tumorigenic effects, and these receptors might be able to be targeted for cancer therapy or prevention. There is also growing evidence that the unique genetic makeup of an individual, such as polymorphisms in genes encoding nAChR subunits, might influence the susceptibility of that individual to the pathobiological effects of nicotine. The emerging knowledge about the carcinogenic mechanisms of nicotine action should be considered during the evaluation of regulations on nicotine product manufacturing, distribution and marketing.

New therapeutic avenues in ulcerative colitis: thinking out of the box

Ulcerative colitis (UC) is a chronic idiopathic inflammatory disease of the gastrointestinal tract that affects the mucosal lining of the colon. Recent epidemiological data show that its incidence and prevalence are increasing in many parts of the world, in parallel with altered lifestyles, improved access to health, improved sanitation and industrialisation rates. Current therapeutic strategies for treating UC have only been moderately successful. Despite major recent advances in inflammatory bowel disease therapeutic resources, a considerable proportion of patients are still refractory to conventional treatment. Less than half of all patients achieve long-term remission, many require colectomy, and the disease still has a major impact on patients' lives. Moreover, recent data point to slightly raised mortality. While these outcomes could be partly improved by optimising current therapeutic strategies, they clearly highlight the need to develop new therapies. Currently, a number of promising and innovative therapeutic approaches are being explored, some of which will hopefully survive to reach the clinic. Until such a time arrives, it is important that a better understanding of the clinical particularities of the disease, an improved knowledge of the host-microbiome negative interactions and of the environmental factors beyond disease development is achieved to obtain the final and desired outcome: to provide better treatment and quality of life for patients with this disabling disease.

Ulcerative colitis: prevention of relapse

The clinical management of ulcerative colitis (UC) involves first treating the acute symptoms to induce remission, and then successfully maintaining it. Oral 5-aminosalicylic acids are safe and useful for maintaining remission in patients with UC. In terms of adherence, a once-daily form of 5-aminosalicylic acid is superior in maintaining remission as compared with split dosing. Patients at high risk of relapse may be candidates for treatment with thiopurines and/or biologics in the early stages of UC. Calcineurin inhibitors, such as cyclosporine and tacrolimus, are effective for severe, steroid-refractory UC patients. It is suggested that these patients use thiopurines as their maintenance therapy once they achieve remission with calcineurin inhibitors. Recent studies have confirmed that biologics are effective for inducing clinical and endoscopic remission of UC, and thus they may improve long-term prognosis of UC.

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.

Anatabine ameliorates experimental autoimmune thyroiditis

Tobacco smoking favorably influences the course of Hashimoto thyroiditis, possibly through the antiinflammatory proprieties of nicotine. In this study we tested anatabine, another tobacco alkaloid, in a model of experimental autoimmune thyroiditis. Experimental autoimmune thyroiditis was induced by different doses of thyroglobulin, to produce a disease of low, moderate, or high severity, in 88 CBA/J female mice: 43 drank anatabine supplemented water and 45 regular water. Mice were bled after immunization and killed to assess thyroid histopathology, thyroglobulin antibodies, T(4), and thyroid RNA expression of 84 inflammatory genes. We also stimulated in vitro a macrophage cell line with interferon-γ or lipopolysaccharide plus or minus anatabine to quantitate inducible nitric oxide synthase and cyclooxygenase 2 protein expression. Anatabine reduced the incidence and severity of thyroiditis in the moderate disease category: only 13 of 21 mice (62%) developed thyroid infiltrates when drinking anatabine as compared with 22 of 23 (96%) controls (relative risk 0.59, P = 0.0174). The median thyroiditis severity was 0.5 and 2.0 in anatabine and controls, respectively (P = 0.0007 by Wilcoxon rank sum test). Anatabine also reduced the antibody response to thyroglobulin on d 14 (P = 0.029) and d 21 (P = 0.045) after immunization and improved the recovery of thyroid function on d 21 (P = 0.049). In the thyroid transcriptome, anatabine restored expression of IL-18 and IL-1 receptor type 2 to preimmunization levels. Finally, anatabine suppressed in a dose-dependent manner macrophage production of inducible nitric oxide synthase and cyclooxygenase 2. Anatabine ameliorates disease in a model of autoimmune thyroiditis, making the delineation of its mechanisms of action and potential clinical utility worthwhile.

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.