Smoking status and response to thiopurines in steroid-dependent inflammatory bowel disease

Comprehensive analysis reveals key genes and environmental toxin exposures underlying treatment response in ulcerative colitis based on in-silico analysis and Mendelian randomization

BACKGROUND

UC is increasingly prevalent worldwide and represents a significant global disease burden. Although medical therapeutics are employed, they often fall short of being optimal, leaving patients struggling with treatment non-responsiveness and many related complications.

MATERIALS AND METHODS

The study utilized gene microarray data and clinical information from GEO. Gene enrichment and differential expression analyses were conducted using Metascape and Limma, respectively. Lasso Regression Algorithm was constructed using glmnet and heat maps were generated using pheatmap. ROC curves were used to assess diagnostic parameter capability, while XSum was employed to screen for small-molecule drugs exacerbating UC. Molecular docking was carried out using Autodock Vina. The study also performed Mendelian randomization analysis based on TwoSampleMR and used CTD to investigate the relationship between exposure to environmental chemical toxicants and UC therapy responsiveness.

RESULTS

Six genes (ELL2, DAPP1, SAMD9L, CD38, IGSF6, and LYN) were found to be significantly overexpressed in UC patient samples that did not respond to multiple therapies. Lasso analysis identified ELL2 and DAPP1 as key genes influencing UC treatment response. Both genes accurately predicted intestinal inflammation in UC and impacted the immunological infiltration status. Clofibrate showed therapeutic potential for UC by binding to ELL2 and DAPP1 proteins. The study also reviews environmental toxins and drug exposures that could impact UC progression.

CONCLUSIONS

We used microarray technology to identify DAPP1 and ELL2 as key genes that impact UC treatment response and inflammatory progression. Clofibrate was identified as a promising UC treatment. Our review also highlights the impact of environmental toxins on UC treatment response, providing valuable insights for personalized clinical management.

The impact of tobacco smoking on treatment choice and efficacy in inflammatory bowel disease

Smoking significantly increases the risk of developing and worsens Crohn's disease (CD), yet protects against the development and reduces the severity of ulcerative colitis. It is less clear whether smoking impacts the efficacy of therapeutics in inflammatory bowel disease (IBD). We review the literature regarding the relationship between smoking and the efficacy of medical and surgical therapy in IBD. Smoking is associated with alterations in thiopurine metabolism and may affect time to disease relapse. The outcomes of anti-tumor necrosis factor therapy in active smokers appear neutral with data lacking for newer biologics. Smoking increases the risk of postoperative recurrence in those requiring resection for CD, likely attributable to perturbations of the gut microbiota although further implications of these for disease onset/progression and treatment efficacy remain unclear. Multiple lifestyle and psychosocial confounders are likely under-recognized cofactors in the association between smoking and IBD. Despite the widely promulgated risks associated with cigarette smoking in CD, more incisive data are required to further elucidate the actual relationship between smoking and disease pathways, while accounting for the several negative cofactors prevalent in smokers which cast uncertainty on the magnitude of the direct effect of smoking on disease pathophysiology and the efficacy of therapy.

Effect of Lifestyle Factors on Outcomes in Patients With Inflammatory Bowel Diseases

Various lifestyle factors including physical activity and obesity, stress, sleep, and smoking may modify the risk of developing inflammatory bowel diseases (IBDs). In patients with established IBD, these lifestyle factors may significantly impact the natural history and clinical outcomes. Recreational exercise decreases the risk of flare and fatigue in patients with IBD. In contrast, obesity increases the risk of relapse and is associated with higher anxiety, depression, fatigue, and pain and higher health care utilization. Obesity also modifies pharmacokinetics of biologic agents unfavorably and is associated with a higher risk of treatment failure. Sleep disturbance is highly prevalent in patients with IBD, independent of disease activity, and increases the risk of relapse and chronic fatigue. Similarly, stress, particularly perceived stress rather than major life events, may trigger symptomatic flare in patients with IBD, although its impact on inflammation is unclear. Cigarette smoking is associated with unfavorable outcomes including the risk of corticosteroid dependence, surgery, and disease progression in patients with Crohn's disease; in contrast, smoking does not significantly impact outcomes in patients with ulcerative colitis, although some studies suggest that it may be associated with a lower risk of flare. The effect of alcohol and cannabis use in patients with IBD is inconsistent, with some studies suggesting that cannabis may decrease chronic pain in patients with IBD, without a significant effect of biological remission. Although these lifestyle factors are potentially modifiable, only a few interventional studies have been conducted. Trials of structured exercise and psychological therapy including mindfulness-based therapies such as meditation and yoga and gut-directed hypnotherapy have not consistently demonstrated benefit in clinical and/or endoscopic disease activity in IBD, although may improve overall quality of life.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Smoking Status at Diagnosis and Subsequent Smoking Cessation: Associations With Corticosteroid Use and Intestinal Resection in Crohn's Disease

BACKGROUND

The impact of smoking at diagnosis and subsequent smoking cessation on clinical outcomes in Crohn's disease (CD) has not been evaluated in a population-based cohort.

METHODS

Using a nationally representative clinical research database, we identified incident cases of CD between 2005 and 2014. We compared the following outcomes: overall corticosteroid (CS) use; flares requiring CS; CS dependency and intestinal surgery between smokers and non-smokers at time of CD diagnosis. Differences in these outcomes were also compared between persistent smokers and smokers who quit within 2 years of diagnosis.

RESULTS

We identified 3553 patients with a new CD diagnosis over the study period of whom 1121 (32%) were smokers. Smokers at CD diagnosis had significantly higher CS-use (56 versus 47%, p < 0.0001), proportionally more CS flares (>1 CS flare/year: 9 versus 6%, p < 0.0001), and higher CS dependency (27 versus 21%, p < 0.0001) than non-smokers. Regression analysis identified smoking at diagnosis to be associated with a higher risk of intestinal surgery (HR 1.64, 95% CI 1.16-2.52). There was a significantly higher proportion of 'quitters' who remained steroid-free through follow-up in comparison to 'persistent smokers' (45.4 versus 37.5%, respectively, p = 0.02). 'Quitters' also had lower rates of CS dependency compared to 'persistent smokers' (24 versus 33%, p = 0.008).

CONCLUSIONS

Smokers at CD diagnosis have higher CS-use, CS dependency and higher risk of intestinal surgery. Quitting smoking appears to have beneficial effects on disease related outcomes, including reducing CS dependency highlighting the importance of offering early smoking cessation support.

Smoking and Inflammatory Bowel Disease: A Comparison of China, India, and the USA

BACKGROUND

Cigarette smoking is thought to increase the risk of Crohn's disease (CD) and exacerbate the disease course, with opposite roles in ulcerative colitis (UC). However, these findings are from Western populations, and the association between smoking and inflammatory bowel disease (IBD) has not been well studied in Asia.

AIMS

We aimed to compare the prevalence of smoking at diagnosis between IBD cases and controls recruited in China, India, and the USA, and to investigate the impact of smoking on disease outcomes.

METHODS

We recruited IBD cases and controls between 2014 and 2018. All participants completed a questionnaire about demographic characteristics, environmental risk factors and IBD history.

RESULTS

We recruited 337 participants from China, 194 from India, and 645 from the USA. In China, CD cases were less likely than controls to be current smokers (adjusted odds ratio [95% CI] 0.4 [0.2-0.9]). There was no association between current or former smoking and CD in the USA. In China and the USA, UC cases were more likely to be former smokers than controls (China 14.6 [3.3-64.8]; USA 1.8 [1.0-3.3]). In India, both CD and UC had similar current smoking status to controls at diagnosis. Current smoking at diagnosis was significantly associated with greater use of immunosuppressants (4.4 [1.1-18.1]) in CD cases in China.

CONCLUSIONS

We found heterogeneity in the associations of smoking and IBD risk and outcomes between China, India, and the USA. Further study with more adequate sample size and more uniform definition of smoking status is warranted.

ACG Clinical Guideline: Preventive Care in Inflammatory Bowel Disease

Recent data suggest that inflammatory bowel disease (IBD) patients do not receive preventive services at the same rate as general medical patients. Patients with IBD often consider their gastroenterologist to be the primary provider of care. To improve the care delivered to IBD patients, health maintenance issues need to be co-managed by both the gastroenterologist and primary care team. Gastroenterologists need to explicitly inform the primary care provider of the unique needs of the IBD patient, especially those on immunomodulators and biologics or being considered for such therapy. In particular, documentation of up to date vaccinations are crucial as IBD patients are often treated with long-term immune-suppressive therapies and may be at increased risk for infections, many of which are preventable with vaccinations. Health maintenance issues addressed in this guideline include identification, safety and appropriate timing of vaccinations, screening for osteoporosis, cervical cancer, melanoma and non-melanoma skin cancer as well as identification of depression and anxiety and smoking cessation. To accomplish these health maintenance goals, coordination between the primary care provider, gastroenterology team and other specialists is necessary.

Improved outcome of acute severe ulcerative colitis while using early predictors of corticosteroid failure and rescue therapies

BACKGROUND AND AIM

Intravenous corticosteroids remain the first line therapy for severe attacks of ulcerative colitis although up to 30-40% of patients do not respond to treatment. The availability of alternative therapies to colectomy and the knowledge of early predictors of response to corticosteroids should have improved the clinical outcomes of patients with severe refractory ulcerative colitis. The aim of the study is to describe the current need, way of use, and efficacy of rescue therapies, as well as colectomy rates in patients with severe ulcerative colitis flares.

METHODS

Between January 2005 and December 2011, all patients admitted in three referral centres for a severe ulcerative colitis flare who received intravenous corticosteroids were identified and clinical and biological data were accurately collected. Patients were followed-up until colectomy, death, or date of data collection.

RESULTS

Sixty-two flares were included. Initial efficacy of intravenous corticosteroids (mild activity or inactive disease without rescue treatment, at day 7 after starting intravenous corticosteroids) was achieved in 50% of flares, and rescue therapies were used in 27 episodes (43%). After a median follow-up of 18 months, the colectomy rate was 6.5%. Failed oral corticosteroids for the index flare were the only baseline feature that predicted the need for rescue therapy and colectomy.

CONCLUSIONS

There is a marked reduction in the colectomy rate and an increased use of medical rescue therapies as compared to historical series. Patients worsening while on oral corticosteroids for a moderate flare are at high risk of rescue therapy and colectomy and, therefore, should be directly treated with rescue therapies instead of attempting intravenous corticosteroids.

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Body Mass Index and Smoking Affect Thioguanine Nucleotide Levels in Inflammatory Bowel Disease

INTRODUCTION

Optimal levels of the thiopurine metabolite, 6-thioguanine nucleotides [6-TGN] correlate with remission of inflammatory bowel disease [IBD]. Apart from variations in the thiopurine methyl transferase [TPMT] gene, little is known about other predictors of 6-TGN levels. Obesity adversely affects response to infliximab and adalimumab and clinical course in IBD, but little is known about the interaction of thiopurines and obesity. We investigated the relationship between body mass index [BMI] and 6-TGN levels and sought to examine other predictors of 6-TGN levels.

METHODS

This retrospective cohort study included patients with concurrent measurements of 6-TGN and BMI. The association between 6-TGN and clinical variables including BMI was estimated using a multivariable linear regression model.

RESULTS

Of 132 observations, 77 [58%] had Crohn's disease and 55 [42%] ulcerative colitis. BMI, smoking, and TPMT levels were associated with 6-TGN levels in multivariable analysis. Every 5kg/m(2) increase in BMI was associated with an 8% decrease in 6-TGN (0.92; 95% confidence interval [CI] 0.87-0.98; p = 0.009). Smokers had higher 6-TGN levels in comparison with non-/ex-smokers [1.43; 95% CI 1.02-2.02; p = 0.041]. Patients with intermediate TPMT had higher 6-TGN compared to those with normal levels [2.13; 95% CI 1.62-2.80; p < 0.001]. Obese patients were more likely to have sub-therapeutic 6-TGN levels and a higher methyl mercaptopurine nucleotide [MMPN/TGN] ratio despite a similar dose of thiopurines.

CONCLUSIONS

Active smoking and intermediate TPMT values were associated with higher 6-TGN levels but increasing BMI resulted in lower 6-TGN and higher MMPN levels. This may explain the worse outcome that has been reported previously in obese IBD subjects.

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.

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.

Effect of azathioprine intolerance on outcomes of inflammatory bowel disease: a cross-sectional study

BACKGROUND

Azathioprine is well established for the maintenance of remission in patients with inflammatory bowel disease (IBD). However, a significant proportion of patients are intolerant to azathioprine. It is not clear if intolerance of azathioprine is a marker of poor prognosis for patients who will have a more aggressive disease or be more likely to require surgery.

OBJECTIVE

To determine if intolerance to azathioprine is a marker of poor prognosis, indicating patients who have a more aggressive disease course, and to analyse the risk factors and causes of intolerance.

METHODS

A cross-sectional study using the Milton Keynes Hospital IBD database was performed to compare azathioprine-intolerant and azathioprine-tolerant patients.

RESULTS

Two hundred and thirty-nine patients met the inclusion criteria comprising 141 patients with Crohn's disease (CD) and 98 patients with ulcerative colitis (UC). Overall, 28.0% of patients were intolerant to azathioprine. Risk factors for intolerance were female sex and age 50-70 years. Common reasons for intolerance were nausea and vomiting (34.3%), deranged liver function tests (28.4%) and headaches (11.9%). In patients with UC, there was no statistical difference in the disease activity scores between those who were azathioprine intolerant versus tolerant. In patients with CD, azathioprine intolerance was associated with significantly worse disease activity; 25% fewer patients were in clinical remission and 20% more had moderate/severe disease. Rates of surgery were similar between the groups for both UC/CD.

CONCLUSIONS

We conclude that azathioprine intolerance acts as a surrogate marker for patients with CD who in future have poorer symptom control. Azathioprine intolerance marks out a group of patients with CD in whom increased vigilance of symptom control and early escalation of treatment is required.

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

BACKGROUND

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

AIM

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

METHODS

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

RESULTS

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

CONCLUSION

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

Does active smoking really influence the course of Crohn's disease? A retrospective observational study

BACKGROUND

Active smoking has been associated with a higher risk of developing Crohn's disease (CD). However, its impact on clinical outcomes has been controversial among studies.

AIMS

To evaluate the influence of active smoking on initial manifestations of CD, the development of disease-related complications, and therapeutic requirements.

METHODS

Patients diagnosed with CD within a ten-year period (1994-2003) were identified. Clinical and therapeutic features until October 2008 or loss of follow-up were recorded. Smoking status was assessed at each major disease-related event (e.g. penetrating and stricturing complications, perianal disease, intestinal resection, introduction of immunomodulators or biological agents).

RESULTS

A total of 259 patients were included in the study with a median follow-up period of 91 months. At diagnosis, 50.5% were active smokers and only 12% of them quit smoking during follow-up, mostly after a major disease-related event occurred. Smoking at diagnosis was not associated with a particular CD presentation. Active smoking did not influence the development of strictures, intraabdominal and perianal penetrating complications, or increased resectional surgery, biological therapy or immunomodulators requirements.

CONCLUSIONS

Patients who develop CD while smoking seem to have a similar disease course to those who never smoked.

Does smoking influence Crohn's disease in the biologic era? The TABACROHN study

BACKGROUND

While most studies have found a negative effect of smoking on Crohn's disease (CD) phenotype, more recent data have failed to reproduce this association, which might be due to a current wider use of thiopurines and biologic therapy. The TABACROHN study aimed at defining the impact of smoking on CD in the largest published series.

METHODS

This multicenter cross-sectional study included 1170 CD patients. Patients were classified as nonsmokers, current smokers, or former smokers according to their present smoking status. Clinical data regarding disease characteristics, treatment, and complications were collected.

RESULTS

Smokers were more frequently under maintenance treatment when compared to nonsmokers. In addition, current smokers presented higher use of biologic drugs compared to nonsmokers. Tobacco exposure and a higher tobacco load were independent predictors of need for maintenance treatment and stenosing phenotype, respectively.

CONCLUSIONS

In the era of early and widespread use of immunosuppressants and biologics, tobacco exposure is an independent predictor of need for maintenance treatment, specifically biologic therapy. The wider use of biologics and immunosuppressants could account for the existence of no major differences in disease behavior and complications between nonsmokers and current smokers.

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

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