Altered microbiota in microscopic colitis

Update on the Epidemiology and Management of Microscopic Colitis

Microscopic colitis is an inflammatory bowel disease that commonly presents with debilitating chronic watery diarrhea. Recent epidemiologic studies and randomized trials of therapeutics have improved the understanding of the disease. Medications, such as nonsteroidal anti-inflammatories, proton pump inhibitors, and antidepressants, have traditionally been considered as the main risk factors for microscopic colitis. However, recent studies have challenged this observation. Additionally, several epidemiologic studies have identified other risk factors for the disease including older age, female sex, smoking, alcohol use, immune-mediated diseases, and select gastrointestinal infections. The diagnosis of microscopic colitis requires histologic assessment of colon biopsies with findings including increased in intraepithelial lymphocytes with or without expansion of the subepithelial collagen band. The pathophysiology is poorly understood but is thought to be related to an aberrant immune response to the luminal microenvironment in genetically susceptible individuals. Antidiarrheal medications, such as loperamide or bismuth subsalicylate, may be sufficient in patients with mild symptoms. In patients with more severe symptoms, treatment with budesonide is recommended. Maintenance therapy is often necessary and several potential treatment strategies are available. Biologic and small molecule treatments seem to be effective in patients who have failed budesonide. There is an unmet need to further define the pathophysiology of microscopic colitis. Additionally, trials with novel therapies, particularly in patients with budesonide-refractory disease, are needed.

Efficacy and Safety of Vedolizumab and Tumor Necrosis Factor Inhibitors in the Treatment of Steroid-refractory Microscopic Colitis: A Systematic Review and Meta-analysis

BACKGROUND

Tumor necrosis factor (TNF-α) inhibitors and the α4β7 integrin antagonist, vedolizumab, have been investigated as treatment options for patients with steroid-refractory microscopic colitis.

AIMS

To evaluate the benefit of vedolizumab and TNF-α inhibitors in patients with steroid-refractory microscopic colitis.

METHODS

Retrospective studies and case series involving patients with steroid-refractory MC who either received vedolizumab, adalimumab, or infliximab were eligible for inclusion. Pooled proportional meta-analyses were used to calculate the rate of clinical remission at induction, clinical response, maintenance of remission, histologic remission, and overall medication related adverse effects. Statistical analysis was performed in R using the metafor and meta packages.

RESULTS

A total of 14 studies involving 164 patients were included. Pooled analysis showed a clinical remission rate of 63.5% [95% CI (0.483; 0.776), I 2 =43% P =0.08], 57.8% [95% CI (0.3895; 0.7571), I 2 =0%, P =0.7541], and 39.3% [95% CI (0.0814; 0.7492), I 2 =66%, P =0.02] for vedolizumab, infliximab, and adalimumab, respectively. The maintenance of remission rates were 65.9% [95% CI (0.389; 0.889), I 2 =67%, P =0.02], 45.3% [95% CI (0.1479; 0.7747), I 2 =0%, P =0.36] and 32.5% [95% CI (0.000; 0.8508), I 2 =53%, P =0.14] in patients who received vedolizumab, infliximab, and adalimumab, respectively. Rate of biological-related adverse events warranting discontinuation of therapy was 12.2%, 32.9%, and 23.0% for the vedolizumab, infliximab, and adalimumab groups, respectively.

CONCLUSION

Vedolizumab and anti-TNF-α agents demonstrated a clinical benefit in the treatment of steroid-refractory microscopic colitis and with a tolerable safety profile. Future randomized controlled trials are needed to compare vedolizumab with TNF-α inhibitors and examine treatment effect on patients' quality of life.

Rifaximin Treatment of Collagenous Colitis: A Randomised, Double-Blind, Placebo-Controlled Trial

Introduction

Collagenous colitis (CC) is a disabling disease primarily affecting elderly women. Sparse, well-documented treatment modalities exist, except for budesonide. Long-term and repetitive treatment with budesonide is often necessary. Rifaximin is a poorly absorbed antibiotic with a positive modulatory effect on gut microbiota. In this randomised, double-blind, placebo-controlled single-centre trial, we test the effect of adding rifaximin in continuation to budesonide on relapse rates in CC.

Methods

Eligible patients with active, biopsy-verified CC received oral budesonide during a 6-week open-label induction phase. Patients in clinical remission after 4 weeks of treatment were randomised to receive either rifaximin or placebo for 4 weeks.

Results

Fifteen patients were randomised to receive either rifaximin (n = 7) or placebo (n = 8). At 12-week follow-up, 2 patients in the rifaximin group were still in remission and none in the placebo group (p = 0.2). The median number of days in remission in the rifaximin group was 42 (interquartile range [IQR] 33-126) compared to 18.5 (IQR 10.5-51.5) in the placebo group (p = 0.189). At 12-week follow-up, the relapse rate per 100 person-days in the placebo group was higher (3.25 [1.40-6.41]) than in the rifaximin group (1.33 [0.43-3.10]).

Conclusion

Although not statistically significant (p = 0.0996), the study suggests a potential improvement in relapse rates within the rifaximin group compared to the placebo group. A major limitation in the study is the small sample size.

Microscopic Colitis: Pathogenesis and Diagnosis

Microscopic colitis is a type of inflammatory bowel disease and is classified as either collagenous colitis or lymphocytic colitis. The typical presentation is chronic watery diarrhea. The disease occurs more frequently in women aged 60-65 years and is increasing in incidence. The pathophysiology of microscopic colitis remains poorly understood and has not been well-described with possible several pathogeneses. To date, the diagnosis of microscopic colitis depends on histological tissue obtained during colonoscopy. Other non-invasive biomarkers, such as inflammatory markers and fecal biomarkers, have been studied in microscopic colitis, but the results remains inconclusive. The approach to chronic diarrhea is important and being able to differentiate chronic diarrhea in patients with microscopic colitis from other diseases, such as inflammatory bowel disease, functional diarrhea, and malignancy, by using non-invasive biomarkers would facilitate patient management. The management of microscopic colitis should be based on each individual's underlying pathogenesis and involves budesonide, bile acid sequestrants, or immunosuppressive drugs in refractory cases. Cigarette smoking and certain medications, especially proton pump inhibitors, should be eliminated, when possible, after the diagnosis is made.

Microbiome Composition in Microscopic Colitis: A Systematic Review

Believed to be a rare cause of chronic diarrhoea, microscopic colitis (MC) is a condition with rising incidence. Many prevalent risk factors and the unknown pathogenesis of MC rationalise the need for studies on microbiota composition. PubMed, Scopus, Web of Science and Embase were searched. Eight case-control studies were included. The risk of bias was assessed with the Newcastle-Ottawa Scale. Clinical details on the study population and MC were poor. The most consistent result among the studies was a decreased Akkermansia genus in faecal samples. Other results were inconsistent due to the different taxonomic levels of the outcomes. Possible changes in different taxa were observed in patients who suffered from MC compared to healthy controls. The alpha diversity compared between MC and the diarrhoea control may suggest potential similarities. The beta diversity in MC compared to healthy and diarrhoeal populations showed no significant outcomes. The microbiome composition in MC possibly differed from the healthy control, but no agreement regarding taxa was made. It might be relevant to focus on possible factors influencing the microbiome composition and its relationship with other diarrhoeal diseases.

Endogenous Levels of Circulating Androgens Are Not Associated with Risk of Microscopic Colitis

BACKGROUND

Microscopic colitis is a chronic inflammatory disease that most commonly affects post-menopausal women. Exogenous hormone use has recently been linked with increased risk of microscopic colitis. Yet, it is unclear whether levels of endogenous sex hormones are also associated with risk of microscopic colitis.

AIM

To evaluate the association between prediagnostic plasma androgens and subsequent risk of microscopic colitis.

METHODS

We conducted a case-control study nested within prospective cohort studies of the Nurses' Health Study (NHS) and NHSII. Cases of microscopic colitis were each matched to two controls according to age, cohort, menopause status, fasting status, and season of plasma collection. Prediagnosis plasma levels of androgens including dehydroepiandrosterone sulfate, testosterone, and sex hormone-binding globulin were measured. We examined the association of each analyte with risk of microscopic colitis using conditional logistic regression models.

RESULTS

Our study included 96 cases of microscopic colitis matched to 190 controls. Plasma levels of testosterone were not associated with risk of microscopic colitis (Ptrend = 0.70). Compared to participants in the lowest quartile of plasma testosterone levels, the aOR of microscopic colitis for women in the highest quartile was 0.88, 95% CI 0.45-1.71. Similarly, we did not observe an association between dehydroepiandrosterone sulfate and sex hormone-binding globulin and risk of microscopic colitis (all Ptrend > 0.52).

CONCLUSION

Among women, prediagnostic circulating levels of testosterone, dehydroepiandrosterone sulfate, and sex hormone-binding globulin are not associated with risk of microscopic colitis.

Microscopic colitis: lymphocytic colitis, collagenous colitis, and beyond

Microscopic colitis (MC) is a chronic inflammatory disease of colon with clinical presentations of chronic, watery, nonbloody diarrhea, and normal or almost normal endoscopic findings. Confirmation of a diagnosis of MC requires microscopic examination on colon biopsy to identify characteristic morphological features, in which 2 main subtypes of MC, lymphocytic colitis (LC) and collagenous colitis (CC), have been described. Although the pathogenesis of MC is still unclear, studies have revealed associations of MC with many risk factors and other diseases such as celiac disease, inflammatory bowel disease, and medication use. Meanwhile, variants of MC, MC incomplete, or MC-like changes in other conditions are still diagnostic dilemmas for pathologists. The goal of this paper is to systemically introduce the clinicopathologic features of MC and focus on unusual features of MC and its associations with other conditions.

Biologic Therapy for Budesonide-refractory, -dependent or -intolerant Microscopic Colitis: a Multicentre Cohort Study from the GETAID

BACKGROUND

Budesonide remains the backbone therapy for microscopic colitis [MC]; however, relapses are frequent, and some patients are intolerant or dependent. Anti-TNF therapy is increasingly used to treat these patients, but available evidence is still limited. The aim of this study was to evaluate the effectiveness and safety of anti-TNF therapy in MC patients failing budesonide.

METHODS

In a multicentre retrospective cohort study, budesonide-refractory, -dependent, or -intolerant MC patients treated with anti-TNF agents were included. Clinical remission was defined as fewer than three bowel movements per day, and clinical response was defined as an improvement in stool frequency of at least 50%.

RESULTS

Fourteen patients were included. Median age was 58.5 years, median disease duration was 25 months, and median follow-up was 29.5 months. Seven patients were treated with infliximab [IFX], and seven with adalimumab. Clinical remission without steroids at 12 weeks was reached in 5/14 [35.7%] patients; all of these received IFX. Clinical response at 12 and 52 weeks, was obtained in 9/14 [64.3%] and 7/14 [50%] patients, respectively. Five patients switched to another anti-TNF agent. When considering both first- and second-line anti-TNF therapies, 7 [50%] patients were in clinical remission at Week 52. Mild to moderate adverse events were reported in six ptients. Two patients were treated with vedolizumab, of whom one had clinical response; one patient treated with ustekinumab had no response.

CONCLUSIONS

This is the first multicentre cohort study showing that half of patients treated with anti-TNF therapy for MC achieved clinical remission in case of budesonide failure.

Microbial Associations With Microscopic Colitis

INTRODUCTION

Microscopic colitis is a relatively common cause of chronic diarrhea and may be linked to luminal factors. Given the essential role of the microbiome in human gut health, analysis of microbiome changes associated with microscopic colitis could provide insights into the development of the disease.

METHODS

We enrolled patients who underwent colonoscopy for diarrhea. An experienced pathologist classified patients as having microscopic colitis (n = 52) or controls (n = 153). Research biopsies were taken from the ascending (ASC) and descending (DES) colon, and the microbiome was characterized with Illumina sequencing. We analyzed the associations between microscopic colitis and microbiome with a series of increasingly complex models adjusted for a range of demographic and health factors.

RESULTS

We found that alpha diversity was significantly lower in cases with microscopic colitis compared with that in controls in the DES colon microbiome. In the DES colon, a series of models that adjusted for an increasing number of covariates found taxa significantly associated with microscopic colitis, including Proteobacteria that was enriched in cases and Collinsella that was enriched in controls. While the alpha diversity and taxa were not significantly associated with microscopic colitis in the ASC colon microbiome, the inference P values based on ASC and DES microbiomes were highly correlated.

DISCUSSION

Our study demonstrates an altered microbiome in cases with microscopic colitis compared with that in controls. Because both the cases and controls experienced diarrhea, we have identified candidate taxa that could be mechanistically responsible for the development of microscopic colitis independent of changes to the microbial community caused by diarrhea.

Collagenous Colitis Possibly Associated with Dipeptidyl Peptidase-4 Inhibitor

A 60-year-old man with type 2 diabetes mellitus treated with a dipeptidyl peptidase-4 (DPP-4) inhibitor was referred to our hospital because of his refractory watery diarrhea. Ileocolonoscopy revealed increased capillary growth, fine granular mucosa, and longitudinal mucosal tears mainly in the left side of the colon. A bioptic examination revealed thickened subepithelial collagen bands, thus confirming the diagnosis of collagenous colitis. Systemic steroid therapy was initiated, but his symptoms recurred when tapering the steroid. However, withdrawal of the DPP-4 inhibitor was successful even after the cessation of steroid therapy. We therefore considered his collagenous colitis to have been caused by the DPP-4 inhibitor.

Microscopic colitis: Etiopathology, diagnosis, and rational management

Microscopic colitis is an inflammatory bowel disease divided into two subtypes: collagenous colitis and lymphocytic colitis. With an increasing incidence of microscopic colitis exceeding those of ulcerative and Crohn's disease among elderly people in some countries, microscopic colitis is a debilitating life experience. Therefore, physicians should be familiar with its clinical features and management strategies because the disease deserves the same attention as the classical inflammatory bowel diseases. Here, state-of-the-art knowledge of microscopic colitis is provided from a global perspective with reference to etiopathology and how to establish the diagnosis with the overall aim to create awareness and improve rational management in clinical practice. The immune system and a dysregulated immune response seem to play a key role combined with risk factors (e.g. cigarette smoking) in genetically predisposed individuals. The symptoms are characterized by recurrent or chronic nonbloody, watery diarrhea, urgency, weight loss, and a female preponderance. As biomarkers are absent, the diagnosis relies on colonoscopy with a histological assessment of biopsy specimens from all parts of the colon. Although the disease is not associated with a risk of colorectal cancer, a recent nationwide, population-based cohort study found an increased risk of lymphoma and lung cancer. Budesonide is the first-line therapy for management, whereas immunomodulatory drugs (including biologics) and drugs with antidiarrheal properties may be indicated in those failing, dependent, or intolerant to budesonide. In microscopic colitis induced by checkpoint inhibitors, a drug class used increasingly for a wide range of malignancies, a more aggressive therapeutic approach with biologics introduced early seems reasonable. However, particular attention needs to be drawn to the existence of incomplete forms of microscopic colitis with the risk of being overlooked in routine clinical settings.

Colonic bacterial diversity and dysbiosis in active microscopic colitis as compared to chronic diarrhoea and healthy controls: effect of polyethylene glycol after bowel lavage for colonoscopy

Background

Most microbiota studies in microscopic colitis patients are performed after diagnostic colonoscopy without considering the potential effect of colonic lavage. Patients may achieve clinical remission after colonoscopy and it is unknown whether lavage-induced changes play a role.

Aim

To assess the effect of polyethylene glycol (PEG) colonic lavage on clinical remission rate, microbial diversity, microbial dysbiosis index and specific microbial changes in patients with active microscopic colitis as compared to other diarrhoeal diseases and healthy controls.

Methods

Fifty-five consecutive patients presenting chronic watery diarrhoea and 12 healthy controls were included. Faecal samples were collected three days before and 30 days after PEG in patients and controls for microbiome analysis.

Results

Clinical remission was observed in 53% of microscopic colitis patients, and in 32% of non-microscopic colitis patients (p = 0.16). Considering patients with persisting diarrhoea after colonoscopy, 71% of non-microscopic colitis patients had bile acid diarrhoea. Baseline Shannon Index was lower in diarrhoea groups than in healthy controls (p = 0.0025); there were no differences between microscopic colitis, bile-acid diarrhoea and functional diarrhoea. The microbial dysbiosis index was significantly higher in microscopic colitis than in bile acid diarrhoea plus functional diarrhoea (p = 0.0095), but no bacterial species showed a significantly different relative abundance among the diarrheal groups.

Conclusions

Dysbiosis is a feature in active microscopic colitis, but loss of microbial diversity was similar in all diarrheal groups, suggesting that faecal microbial changes are not due to microscopic colitis itself but associated with stool form. A considerable number of microscopic colitis patients achieved clinical remission after colonoscopy, but we were unable to demonstrate related PEG-induced changes in faecal microbiome.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12876-022-02392-w.

Microscopic Colitis Patients Possess a Perturbed and Inflammatory Gut Microbiota

BACKGROUND

Microscopic colitis (MC), an inflammatory disease of the colon, is characterized by chronic non-bloody diarrhea with characteristic inflammation and for some, collagen deposits in mucosal biopsies. The etiology of MC is unclear, although previous findings implicate luminal factors and thus the gut microbiome. However, the relationships between fecal microbiota and MC are relatively unexplored.

METHODS

Stool microbiota of MC (n = 15) and healthy controls (HC; n = 21) were assessed by 16S rRNA V4 amplicon sequencing and analysis performed in QIIME. Gut microbiota functions were predicted using Piphillin and inflammatory potential assessed using an in vitro HT29 colonocyte cell assay.

RESULTS

MC patient fecal microbiota were less diverse (Faiths index; p < 0.01) and compositionally distinct (PERMANOVA, weighted UniFrac, R² = 0.08, p = 0.02) compared with HC subjects. MC microbiota were significantly depleted of members of the Clostridiales, enriched for Prevotella and more likely to be dominated by this genus (Chi² = 0.03). Predicted pathways enriched in MC microbiota included those related to biosynthesis of antimicrobials, and sphingolipids, to glycan degradation, host defense evasion, and Th17 cell differentiation and activation. In vitro, exposure of cultured colonocytes to cell-free products of MC patient feces indicates reduced gene expression of IL-1B and occludin and increased GPR119 and the lymphocyte chemoattractant CCL20.

CONCLUSION

MC gut microbiota are distinct from HC and characterized by lower bacterial diversity and Prevotella enrichment and distinct predicted functional pathways. Limited in vitro experiments indicate that compared with cell-free products from healthy fecal microbiota, MC microbiota induce distinct responses when co-cultured with epithelial cells, implicating microbiota perturbation in MC-associated mucosal dysfunction.

Disease-associated dysbiosis and potential therapeutic role of Akkermansia muciniphila, a mucus degrading bacteria of gut microbiome

The unique functionality of Akkermansia muciniphila in gut microbiota indicates it to be an indispensable microbe for human welfare. The importance of A. muciniphila lies in its potential to convert mucin into beneficial by-products, regulate intestinal homeostasis and maintain gut barrier integrity. It is also known to competitively inhibit other mucin-degrading bacteria and improve metabolic functions and immunity responses in the host. It finds a pivotal perspective in various diseases and their treatment. It has future as a promising probiotic, disease biomarker and therapeutic agent for chronic diseases. Disease-associated dysbiosis of A. muciniphila in the gut microbiome makes it a potential candidate as a biomarker for some diseases and can provide future theranostics by suggesting ways of diagnosis for the patients and best treatment method based on the screening results. Manipulation of A. muciniphila in gut microbiome may help in developing a novel personalized therapeutic action and can be a suitable next generation medicine. However, the actual pathway governing A. muciniphila interaction with hosts remains to be investigated. Also, due to the limited availability of products containing A. muciniphila, it is not exploited to its full potential. The present review aims at highlighting the potential of A. muciniphila in mucin degradation, contribution towards the gut health and host immunity and management of metabolic diseases such as obesity and type 2 diabetes, and respiratory diseases such as cystic fibrosis and COVID-19.

Diagnosis and Management of Microscopic Colitis in Pediatric Patients

Microscopic colitis (MC) is an inflammatory disease of the colon, characterized by chronic watery diarrhea with distinguishing histologic findings despite normal endoscopic appearance of the colonic mucosa. MC is a common cause of diarrhea in older adults, though it has been infrequently reported in children and adolescents. As MC is rare in the pediatric population, and the clinical presentation is non-specific, increased awareness of this disease amongst pediatric clinicians and pathologists is essential for timely diagnosis, which requires performing colonoscopy with biopsy. The etiology of MC is incompletely understood, but current theories in pathogenesis inform management strategies. The goals of management in pediatric MC should be to achieve symptomatic improvement while minimizing adverse effects of treatment. Many patients who achieve clinical response have symptomatic recurrence after discontinuation of initial therapy, and may require maintenance medication therapy to sustain remission. This review aims to summarize the epidemiology and risk factors, clinical features, diagnosis, theories regarding pathogenesis, and suggested management approaches for MC in the pediatric population.

Pathogenesis of Microscopic Colitis: A Systematic Review

BACKGROUND

Whereas the exact aetiology of microscopic colitis [MC] remains unknown, a dysregulated immune response to luminal factors or medications is the most accepted pathogenesis hypothesis.

METHODS

We conducted a systematic review of the pathogenesis of MC. We applied the Joanna Briggs Institute methodologies and the PRISMA statement for the reporting of systematic reviews [PROSPERO Trial Identifier: CRD42020145008]. Populations, Exposure of interest, and Outcome [PEO] questions were used to explore the following topics in MC: 1] intestinal luminal factors; 2] autoimmunity; 3] innate immunity; 4] adaptive immunity; 5] extracellular matrix; 6] genetic risk factors; and 7] mechanism of diarrhoea. A search was done in PubMed, Embase, and Web of Science up to February 2020. A narrative description was performed explaining the findings for each aspect of MC aetiopathogenesis.

RESULTS

Thirty-eight documents provided evidence for PEO1, 100 for PEO2, 72 for PEO3 and 4, 38 for PEO5, 20 for PEO6, and 23 for PEO7. The majority of documents were cohorts, case reports, and case series, with a few case-control and some experimental studies. Consistency among data provided by different studies was considered to support pathogenetic hypotheses. MC is a multifactorial disease believed to involve innate and adaptive immune responses to luminal factors, genetic risk, autoimmunity, and extracellular matrix alterations, all contributing by varied mechanisms to watery diarrhoea.

CONCLUSIONS

This is the first systematic review on the aetiology of MC supporting the notion that MC is a multifactorial disease. However, high-profile studies are lacking, and most evidence derives from small heterogeneous studies.

Exploring how microbiome signatures change across inflammatory bowel disease conditions and disease locations

Understanding the variables that influence microbiome studies is critical for successful translational research. Inflammatory bowel disease (IBD) is a complex group of diseases that can present at multiple locations within the Gastrointestinal tract. Here, using the FAMISHED study cohort, we aimed to investigate the relationship between IBD condition, IBD disease location, and the microbiome. Signatures of the microbiome, including measures of diversity, taxonomy, and functionality, all significantly differed across the three different IBD conditions, Crohn’s disease (CD), ulcerative colitis (UC), and microscopic colitis (MC). Notably, when stratifying by disease location, patients with CD in the terminal ileum were more similar to healthy controls than patients with CD in the small bowel or colon, however no differences were observed at different disease locations across patients with UC. Change in taxonomic composition resulted in changes in function, with CD at each disease location, UC and MC all having unique functional dysbioses. CD patients in particular had deficiencies in Short-Chain Fatty Acid (SCFA) pathways. Our results demonstrate the complex relationship between IBD and the microbiome and highlight the need for consistent strategies for the stratification of clinical cohorts and downstream analysis to ensure results across microbiome studies and clinical trials are comparable.

Microscopic colitis

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

Microscopic Colitis: A Concise Review for Clinicians

Microscopic colitis (MC) is an inflammatory disease of the colon and a common cause of chronic watery diarrhea, predominantly in older patients. Microscopic colitis encompasses 2 different subtypes, lymphocytic colitis and collagenous colitis. The colon typically appears normal endoscopically in MC, and the diagnosis requires histologic evaluation. Whereas recent studies suggest that the incidence of MC has plateaued, given the aging of the population, the prevalence of MC will likely increase. Risk factors for MC include increasing age; female sex; presence of other autoimmune diseases; and possibly use of certain medications, including proton pump inhibitors, nonsteroidal anti-inflammatory drugs, selective serotonin reuptake inhibitors, and statins. The clinical presentation of MC is nonspecific and includes watery nonbloody diarrhea, nocturnal stools, fecal urgency, abdominal pain, arthralgias, and weight loss. The disease course of MC is variable; some patients experience occasional, intermittent symptoms, and others demonstrate more chronic and even progressive symptoms. The approach to treatment is similar for both lymphocytic colitis and collagenous colitis and should be guided by the severity of the patient's symptoms. Offending medications highly associated with MC should be eliminated as clinically possible. In patients with mild symptoms, antidiarrheals such as loperamide are the initial choice; for moderate-severe disease, budesonide is recommended for induction of clinical remission. In those with recurrent symptoms, low-dose budesonide may be required for maintenance therapy with close monitoring for potential adverse effects. In rare cases, immunomodulators may be required.

Transcriptomic Profiling of Collagenous Colitis Identifies Hallmarks of Nondestructive Inflammatory Bowel Disease

BACKGROUND AND AIMS

The pathophysiology of the inflammatory bowel disease collagenous colitis (CC) is poorly described. Our aim was to use RNA sequencing of mucosal samples from patients with active CC, CC in remission, refractory CC, ulcerative colitis (UC), and control subjects to gain insight into CC pathophysiology, identify genetic signatures linked to CC, and uncover potentially druggable disease pathways.

METHODS

We performed whole transcriptome sequencing of CC samples from patients before and during treatment with the corticosteroid drug budesonide, CC steroid-refractory patients, UC patients, and healthy control subjects (n = 9-13). Bulk mucosa and laser-captured microdissected intestinal epithelial cell (IEC) gene expression were analyzed by gene set enrichment and gene set variation analyses to identify significant pathways and cells, respectively, altered in CC. Leading genes and cells were validated using reverse-transcription quantitative polymerase chain reaction or immunohistochemistry.

RESULTS

We identified an activation of the adaptive immune response to bacteria and viruses in active CC that could be mediated by dendritic cells. Moreover, IECs display hyperproliferation and increased antigen presentation in active CC. Further analysis revealed that genes related to the immune response (DUOX2, PLA2G2A, CXCL9), DNA transcription (CTR9), protein processing (JOSD1, URI1), and ion transport (SLC9A3) remained dysregulated even after budesonide-induced remission. Budesonide-refractory CC patients fail to restore normal gene expression, and displayed a transcriptomic profile close to UC.

CONCLUSIONS

Our study confirmed the implication of innate and adaptive immune responses in CC, governed by IECs and dendritic cells, respectively, and identified ongoing epithelial damage. Refractory CC could share pathomechanisms with UC.

Faecal microbiota transfer in patients with microscopic colitis - a pilot study in collagenous colitis

OBJECTIVES

Faecal microbiota transfer (FMT) consists of the infusion of donor faecal material into the intestine of patients with the aim to restore a disturbed gut microbiota.

METHODS

In this pilot study (NCT03275467), the effect of three repeated FMTs (day 0, two weeks, four weeks) was studied and followed up for six months in nine collagenous colitis (CC) patients, using two stool donors.

RESULTS

Five patients had an active disease at the time of baseline sampling. The primary endpoint (remission at six weeks, defined as <3 stools whereof <1 watery stool per day) was achieved by two of these patients, and by one at eight weeks. Overall, in all nine patients, FMT did not result in a significant reduction of watery stools, assessed by daily diary. However, diarrhoea (assessed by gastrointestinal symptom rating scale) was significantly improved at four (p = .038) and eight weeks (p = .038), indigestion at eight (p = .045) and 12 weeks (p = .006), disease-related worries at four (p = .027) and eight weeks (p = .027), and quality of life at six months (p = .009). FMT resulted in an increased number of lamina propria lymphocytes, possibly indicating an initial mucosal immune activation. No serious adverse events, no systemic effects, and no changes in faecal calprotectin and psychological symptoms were observed.

CONCLUSIONS

FMT is able to improve symptoms in a yet undefined subset of CC patients. Further studies could help to characterise this subset and to understand if these results can be generalised to all microscopic colitis patients.

High risk of microscopic colitis after Campylobacter concisus infection: population-based cohort study

OBJECTIVE

Microscopic colitis (MC) encompasses the two histopathological distinct entities of collagenous colitis (CC) and lymphocytic colitis (LC). In this Danish population-based cohort study, we examined the risk of MC following stool culture with Campylobacter concisus, C. jejuni, non-typhoidal Salmonella or a culture-negative stool test.

DESIGN

We identified patients with a first-time positive stool culture with C. concisus, C. jejuni, non-typhoidal Salmonella or negative stool test, from 2009 through 2013 in North Denmark Region, Denmark, and matched each with 10 population comparisons. All subjects were followed up until 1 March 2018 using Systematised Nomenclature of Medicine codes from The Danish Pathology Register for incident diagnoses of CC and LC. We computed risk and adjusted HRs with 95% CIs for MC among patients and comparisons.

RESULTS

We identified 962 patients with C. concisus, 1725 with C. jejuni, 446 with Salmonella and 11 825 patients with culture-negative stools. The MC risk and HR versus comparisons were high for patients with C. concisus (risk 6.2%, HR 32.4 (95% CI 18.9 to 55.6)), less for C. jejuni (risk 0.6%, HR 3.7 (95% CI 1.8 to 7.7)), low for Salmonella (risk 0.4%, HR 2.2 (95% CI 0.5 to 10.8)) and for patients with negative stool testing (risk 3.3%, HR 19.6 (95% CI 16.4 to 23.4)). After exclusion of the first year of follow-up, the HRs were 9.3 (95% CI 4.1 to 20.1), 2.2 (95% CI 0.9 to 5.4), 1.3 (95% CI 0.2 to 11.1) and 5.6 (95% CI 4.6 to 7.2), respectively.

CONCLUSION

A high risk of MC was observed following C. concisus in stools. Further studies are needed to elucidate any underlying biological mechanisms.

Long-Term Natural History of Microscopic Colitis: A Population-Based Cohort

Data on long-term natural history of microscopic colitis (MC), including collagenous (CC) and lymphocytic colitis (LC), are lacking.

Effects of long-distance transportation on blood constituents and composition of the nasal microbiota in healthy donkeys

BACKGROUND

This study aims to determine the effects of transportation on the nasal microbiota of healthy donkeys using 16S rRNA sequencing.

RESULTS

Deep nasal swabs and blood were sampled from 14 donkeys before and after 21 hours' long-distance transportation. The values of the plasma hormone (cortisol (Cor), adrenocorticotrophic hormone (ACTH)), biochemical indicators (total protein (TP), albumin (ALB), creatinine (CREA), lactic dehydrogenase (LDH), aspartate transaminase (AST), creatine kinase (CK), blood urea (UREA), plasma glucose (GLU)) and blood routine indices (white blood cell (WBC), lymphocyte (LYM), neutrophil (NEU), red blood cell (RBC), hemoglobin (HGB)) were measured. 16S rRNA sequencing was used to assess the nasal microbiota, including alpha diversity, beta diversity, and phylogenetic structures. Results showed that levels of Cor, ACTH, and heat-shock protein 90 (HSP90) were significantly increased (p < 0.05) after long-distance transportation. Several biochemical indicators (AST, CK) and blood routine indices (Neu, RBC, and HGB) increased markedly (p < 0.05), but the LYM decreased significantly (p < 0.05). Nine families and eight genera had a mean relative abundance over 1%. The predominant phyla in nasal microbiota after and before transportation were Proteobacteria, Firmicutes, Actinobacteria, and Bacteroidetes. Transportation stress induced significant changes in terms of nasal microbiota structure compared with those before transportation based on principal coordinate analysis (PCoA) coupled with analysis of similarities (ANOSIM) (p < 0.05). Among these changes, a notably gain in Proteobacteria and loss in Firmicutes at the phylum level was observed.

CONCLUSIONS

These results suggest transportation can cause stress to donkeys and change the richness and diversity of nasal microbiota. Further studies are required to understand the potential effect of these microbiota changes on the development of donkey respiratory diseases.

The Gut Microbiota in Collagenous Colitis Shares Characteristics With Inflammatory Bowel Disease-Associated Dysbiosis

In inflammatory bowel disease (IBD), an aberrant immune response to gut microbiota is important, but the role of the microbiota in collagenous colitis (CC) is largely unknown. We aimed to characterize the microbiota of patients with CC compared with that of healthy control and patients with IBD.

Campylobacter concisus is prevalent in the gastrointestinal tract of patients with microscopic colitis

OBJECTIVES

Microscopic colitis (MC) is potentially induced by an inflammatory reaction to a luminal gut factor. The emerging pathogen Campylobacter concisus is associated with prolonged diarrhoea and subsequently increased risk of MC. We aimed to examine the prevalence of C. concisus in clinical samples from MC patients, analyse the subtypes collagenous colitis (CC) and lymphocytic colitis (LC), and characterise C. concisus isolates from MC patients by genomic sequencing.

METHODS

Mucosal biopsies were collected by sigmoidoscopy in 55 MC patients (CC n = 34, LC n = 21). Saliva and faecal samples were also collected. A two-step cultivation method and PCR established C. concisus prevalence. Biopsy and faecal isolates were sequenced for genomic analysis.

RESULTS

Cultivation revealed C. concisus in saliva 55/55, faeces 14/55 and biopsies 69/436, which was confirmed by PCR in faeces 28/55 and biopsies 215/430. Interestingly, biopsy prevalence was higher in CC patients than in LC patients both by cultivation (50/270 vs.19/166, p = .058) and by PCR (175/270 vs. 40/160, p < .0001). Long disease duration also affected biopsy prevalence both by cultivation 30/244 (<2 years) vs. 39/192 (>2 years) (p = .025) and by PCR 103/239 (<2 years) vs. 112/191 (>2 years) (p = .002). Genomic analysis on sixty biopsy and twenty faecal isolates revealed division into two clusters/genomospecies and a high presence of various, putative virulence genes (zot, exotoxin 9 and hcp).

CONCLUSIONS

Campylobacter concisus was prevalent in MC patients. Interestingly, the biopsy prevalence differed in biopsies from CC and LC patients and with regard to disease duration. Further studies are needed to elucidate this possible association.

Les colites microscopiques

Microscopic colitis is frequently found as a cause of chronic watery diarrhea in women after menopause. The disease can be associated with a medication side effect in half of the patients (non-steroidal anti-inflammatory drugs or proton pump inhibitors for instance). Colonic biopsies are mandatory for the diagnosis of microscopic colitis and should be performed in several locations of the colon. Management of microscopic colitis is first based on avoiding iatrogenic factors and smoking together with symptomatic treatment of diarrhea (loperamide, cholestyramine). In case of failure or severe symptoms, budesonide is the key treatment. The aim of the treatment is to achieve clinical remission, defined as less than 3 liquid stools per day, to improve quality of life. After a first course of budesonide, recurrence of diarrhea is frequent and a maintenance therapy can be prescribed for several months. In case of intolerance or refractoriness, second-line therapy (immunosuppressants, biological therapy, surgery) should be discussed in multidisciplinary team meeting.

Microscopic colitis: pathophysiology and clinical management

Microscopic colitis is a chronic inflammatory disease of the colon that frequently causes chronic watery diarrhoea that might be accompanied by abdominal pain, nocturnal diarrhoea, urgency, and faecal incontinence. These symptoms lead to poor quality of life and increased health-care costs. Diagnosis relies on histological examination of multiple biopsy samples from the colonic mucosa, which often show no or only few abnormalities on endoscopy. Two major histological subtypes can be distinguished-collagenous colitis and lymphocytic colitis-but incomplete and variant forms with fewer characteristic features have been reported. Here we summarise the latest evidence on epidemiology, pathogenesis, and risk factors, and discuss established and novel therapeutic options for clinical remission. Finally, we propose an updated treatment algorithm. Further prospective studies are needed to clarify the natural history of microscopic colitis, supported by validated criteria for the assessment of disease activity.

Ambient air quality as risk factor for microscopic colitis - A geographic information system (GIS) study

BACKGROUND

Microscopic colitis (MC) is considered a multifactorial disease, strongly associated with smoking. However, little is known about the role of environmental factors such as ambient air pollution in MC pathophysiology. There is an overlap in components of cigarette smoke and ambient air pollution. Therefore, the aim of this study was to explore an independent association between ambient air quality and MC.

METHODS

A case-control study was performed. MC cases in South Limburg, the Netherlands, diagnosed between 2000 and 2012, were retrieved from the national pathology registry and matched to non-MC controls from the same area based on age (±2 years) and gender. A stable residential address for ≥3 years was required. Residential land use, proximity to major road, and concentrations of air pollution compounds, were determined using a Geographic Information System (GIS). Univariate and multivariable regression analyses were corrected for age, gender and smoking status.

RESULTS

In total, 345 MC cases (78.6% female) and 583 matched controls (77.2% female) were included. In the univariate analyses, the percentage of urban green within a 500 m buffer and residential proximity to the nearest highway were associated with MC (both p < 0.10). On the multivariable level only a higher age at diagnosis (OR 1.02, 95%-CI 1.01-1.04) and current smoking at index date (OR 4.30; 95%-CI 3.01-6.14) were significantly associated with MC.

CONCLUSION

Based on the current findings, ambient air quality does not seem to be an important risk factor for MC, in contrast to the well-known risk factors age and current smoking.

Marked regional variations in the prevalence of inflammatory bowel disease in a limited geographical region are not associated with compounds in the drinking water

Objective: The incidence of autoimmune diseases, especially inflammatory bowel disease (IBD), has increased substantially. Globally, there are vast differences varying from 0.2/10⁵ in some Asian countries to over 80/10⁵ in the Faroe Islands. Environmental factors have been suggested as triggers. The aim was to investigate the incidence and prevalence of IBD in the 33 municipalities in the county Scania in Southern Sweden, an area comprising 100 × 100 km with 1,274,069 inhabitants. Furthermore, we wanted to explore whether compounds in the drinking water could contribute to IBD; one report from Norway has suggested that iron in drinking water could contribute to UC.Methods: Patients with CD and UC were identified through the ICD-10 diagnosis database during the period 2000-2013. Water analyses for pH, alkaline, nitrate, sulphate, iron, magnesium and calcium were based on established methods and compared with the prevalence of IBD using Student's t-test.Results: A total number of 8925 patients were identified. The incidence for CD and UC were high (mean 16.4/10⁵, range 13.6-17.9 and 25.3/10⁵, range 21.3-28.0, respectively). The prevalence varied substantially (p < .0001 for both; CD mean 0.30%, range 0.15-0.42 and UC mean 0.42%, range 0.32-0.56). No correlation between IBD and the chemical compounds in the drinking water could be shown.Conclusions: The incidence rates of both CD and UC were high. The prevalence varied from 200% to 300% between the municipalities, despite the limited geographical area indicating that local conditions are of importance. However, chemical compounds in the water were not associated with this variation.

Single-centre experience with anti-tumour necrosis factor treatment in budesonide-refractory microscopic colitis patients

Background

Microscopic colitis is an inflammatory bowel disease that causes chronic, watery diarrhoea. Microscopic colitis is usually effectively treated with budesonide, but some patients are refractory. Data on alternative treatments are sparse.

Aims

The purpose of this study was to retrospectively evaluate outcome of microscopic colitis patients receiving anti-tumour necrosis factor therapy at our centre.

Methods

Treatment results, including side effects, for all microscopic colitis patients receiving anti-tumour necrosis factor therapy were registered at week 12 and at end of follow-up. Clinical remission was defined as a mean of <3 stools and <1 watery stools/day/week and clinical response as a 50% reduction of mean stool frequency/day/week. Induction and maintenance treatment was either adalimumab or infliximab.

Results

The study cohort comprised 18 patients; mean age at diagnosis was 47 years (range 19-77). Ten and eight patients, respectively, received adalimumab and infliximab as first-line anti-tumour necrosis factor; seven patients received second-line anti-tumour necrosis factor due to non-response, loss of response or side effects. At week 12, 9/18 patients had achieved remission, 6/18 were responders and 3/18 were non-responders. Of the nine remission patients, 3/18 (16%) had long-lasting clinical remission post-induction therapy alone. Five patients (28%) (one first-line, four second-line anti-tumour necrosis factor) were in remission and one patient (6%) responded to maintenance treatment; follow-up was mean 22 (range 4-60) months. Six patients (33%) had minor, reversible side effects.

Conclusions

Over half of budesonide-refractory microscopic colitis patients can achieve clinical remission or response on anti-tumour necrosis factor agents. Prospective studies are mandatory to evaluate the efficacy and safety of anti-tumour necrosis factor treatments in budesonide-refractory microscopic colitis.

An altered composition of the microbiome in microscopic colitis is driven towards the composition in healthy controls by treatment with budesonide

Background and aim: Microscopic colitis (MC) is an inflammatory disease of the bowel, hypothetically induced by an immunologic response to a luminal microbial agent. We aimed to characterize the microbiome composition in MC and subtypes collagenous colitis (CC) and lymphocytic colitis (LC) and to identify a possible microbial effect of treatment. Method: Stool samples were collected from MC patients prior to treatment, at 8 weeks (during treatment) and at 16 weeks (after treatment), and from healthy controls, not receiving treatment, at matched time-points. Microbiome composition was analyzed by sequencing of the 16S and 18S genes. Differences between patients and controls were analyzed by Shannon's diversity index (mean, standard deviation (SD)) and principal coordinate analysis (PCoA) complemented with a permanova test of UniFrac distances. Results: Ten LC patients, 10 CC patients and 10 controls were included. By PCoA, the bacterial composition in MC patients differed from controls at baseline (p = .02), but not during and after treatment (p = .09 and p = .33, respectively). At baseline, bacterial diversity was lower in MC patients compared to controls (2.5, SD: 0.5 vs 3.5, SD: 0.3, p < .05). Diversity in MC patients increased during (3.0, SD: 0.6) and after treatment and (2.9, SD: 0.5) compared with baseline (p < .01). Eukaryotes were detected in fewer samples from MC patients compared with controls (11/20 (55%) vs. 9/10 (90%), p = .06) with no effect of treatment. Conclusion: Microbiome composition is altered in MC patients. During and after treatment with budesonide the microbiome composition in MC patients was driven towards the composition in healthy controls.

Smoking and Risk of Microscopic Colitis: A Systematic Review and Meta-analysis

BACKGROUND

The association between smoking and inflammatory bowel disease has long been recognized, but its role in the development of microscopic colitis is less well defined. This systematic review and meta-analysis was conducted with the aims to identify all available studies on the association between smoking and risk of microscopic colitis and to synthesize their results.

METHODS

The MEDLINE and EMBASE databases were searched from inception to May 2018 for cohort studies and case-control studies that compared the risk of microscopic colitis among current/former smokers vs individuals who have never smoked. Odds ratios (ORs) and corresponding 95% confidence intervals (CIs) were extracted from the included studies and pooled together using a random-effects model, generic inverse variance method of DerSimonian and Laird. Between-study heterogeneity was quantified using the Q statistic and I2. Publication bias was assessed using funnel plots.

RESULTS

Seven studies (2 cohort studies and 5 case-control studies) with 262,312 participants met the eligibility criteria and were included in the meta-analysis. Relative to never-smokers, current smokers had significantly increased odds of microscopic colitis, with a pooled OR of 2.99 (95% CI, 2.15-4.15; I2, 64%). Former smokers also had significantly higher odds of microscopic colitis compared with never-smokers, with a pooled OR of 1.63 (95% CI, 1.37-1.94; I2, 0%). Funnel plots were symmetric and did not provide suggestive evidence of publication bias for both analyses.

CONCLUSIONS

The current systematic review and meta-analysis found a significantly higher risk of microscopic colitis among current smokers compared with never-smokers. The risk attenuated among former smokers but remained significantly higher among never-smokers.

Proinflammatory Sulfur-Reducing Bacteria Are More Abundant in Colonic Biopsies of Patients with Microscopic Colitis Compared to Healthy Controls

BACKGROUND

Microscopic colitis (MC), a subtype of inflammatory bowel disease, is a chronic condition of unknown etiology. Recent evidence has linked MC with intriguing changes in the stool microbiota, which may be linked to disease pathogenesis. The composition of the mucosal microbiome in patients with MC remains unclear.

METHODS

We performed a cross-sectional study comparing colonic tissue samples from patients with MC to those of healthy controls at the Michael E. DeBakey VA Medical Center. We included adults older than 18 who underwent a colonoscopy with biopsies to evaluate chronic diarrhea. Cases were defined by histology consistent with MC and controls by the absence of histologic disease. We conducted structured chart review to exclude other gastrointestinal diseases and obtain demographic (age, sex, race) and clinical (duration of symptoms and concurrent medications) information for cases and controls. We extracted bacterial DNA from formalin-fixed paraffin-embedded tissue samples and sequenced the v4 region of the 16S rRNA gene. Operational taxonomic unit (OTU) clustering was performed using UPARSE, and OTUs were assigned using the SILVA database. Statistical analysis was performed in QIIME and LEfSe. Comparisons with FDR-adjusted p values of less than 0.05 were considered statistically significant.

RESULTS

We included 20 MC patients and 20 controls with mean ages of 62 and 54, respectively. Most cases were White (95%), 60% had symptoms for greater than 12 months, and 50% were taking PPIs and NSAIDs at the time of their diagnosis. Compared to controls, MC patients had a significant increase in the proinflammatory sulfur-reducing bacterial family Desulfovibrionales. The Coriobacteriaceae family, abundant in the healthy gut, was significantly decreased in MC cases. There was also an increase in the genus Actinomyces in MC patients on PPI and an increase in the class Bacilli among those taking NSAIDs.

DISCUSSION

Patients with MC have an increase in the proinflammatory family Desulfovibrionales. Actinomyces and Bacilli were associated with medications (PPI and NSAID) known to increase the risk of MC. Our findings may have important implications for understanding the pathogenesis of MC.

Impact of CFTR modulation with Ivacaftor on Gut Microbiota and Intestinal Inflammation

Cystic fibrosis (CF) is caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. Next to progressive airway disease, CF is also associated with intestinal inflammation and dysbiosis. Ivacaftor, a CFTR potentiator, has improved pulmonary and nutritional status but its effects on the intestinal microbiota and inflammation are unclear. Hence, we assessed the changes on the intestinal microbial communities (16S rRNA variable 3 gene region) and inflammatory markers (calprotectin and M2-pyruvate kinase [M2-PK]) in 16 CF individuals (8 children and 8 adults) before and after (median 6.1 months) ivacaftor. Stool calprotectin significantly decreased following ivacaftor (median [IQR]: 154.4 [102.1–284.2] vs. 87.5 [19.5–190.2] mg/kg, P = 0.03). There was a significant increase in Akkermansia with ivacaftor. Increased abundance of Akkermansia was associated with normal stool M2-PK concentrations, and decreased abundances of Enterobacteriaceae correlated with decreased stool calprotectin concentrations. In summary, changes in the gut microbiome and decrease in intestinal inflammation was associated with Ivacaftor treatment among individuals with CF carrying at least one gating CFTR mutation. Thus, CFTR-modifying therapy may adequately improve the aberrant pathophysiology and milieu of the CF gut to favor a more healthy microbiota, which in turn reduces intestinal inflammation.

Identification of Menopausal and Reproductive Risk Factors for Microscopic Colitis-Results From the Nurses' Health Study

BACKGROUND & AIMS

Microscopic colitis is a chronic inflammatory disorder of the colon primarily affecting postmenopausal women. However, the relation between hormonal determinants, including reproductive and menopausal factors, and risk of microscopic colitis has yet to be characterized.

METHODS

We collected data from 227,766 women who participated in the Nurses' Health Study (NHS) and the NHSII without a baseline history of microscopic colitis. Reproductive and menopausal factors were assessed in 1988 in the NHS and 1989 in the NHSII and updated biennially. Cases of microscopic colitis were confirmed through review of pathology records. We used Cox proportional hazards modeling to estimate hazard ratios and 95% confidence intervals.

RESULTS

Through 2014 in the NHS and 2015 in the NHSII, we confirmed 275 incident cases of microscopic colitis over 5,147,282 person-years. Compared with never use, current use of menopausal hormone therapy was associated with increased risk of microscopic colitis (multivariable-adjusted hazard ratio 2.64; 95% confidence interval 1.78-3.90). The risk increased with longer duration of use (P for trend < .0001) and decreased after discontinuation (P for trend = .002). The association did not differ according to disease subtype (P for heterogeneity = .34). Similarly, ever use of oral contraceptives was associated with increased risk of microscopic colitis (multivariable-adjusted hazard ratio 1.57; 95% confidence interval 1.16-2.13). There were no associations between age at menarche, parity, age at first birth, age at menopause, or menopause type and incident microscopic colitis.

CONCLUSIONS

In 2 large prospective cohort studies, we observed an association between exogenous hormone use and incident microscopic colitis. Further studies are needed to determine the mechanisms underlying these associations.

Escherichia coli O101-induced diarrhea develops gut microbial dysbiosis in rats

Enterotoxigenic Escherichia coli (ETEC)-induced diarrhea is a devastating disease and one of the third leading causes of infectious disease-associated mortalities worldwide. Despite recent advances in the identification of the association between gut microbiota and diarrhea, a lack of understanding exists on the status of gut microbiota in rats treated with ETEC. In the present study, a rat model of Escherichia (E.) coli O₁₀₁-induced diarrhea was established. The diarrhea incidence and index, as well as histological changes, were assessed. In addition, Illumina MiSeq sequencing of V3-V4 hypervariable regions of 16S ribosomal RNA was employed to investigate the changes in the gut microbiota profiles in the feces of the diarrhea rats. The results indicated that E. coli O₁₀₁ increased the diarrhea index and injury in the intestinal tissues, whereas it decreased the bacterial richness and shifted the distribution pattern of the bacterial communities in the phylum, order and genus levels in the fecal samples. Notably, the proportion of bacteria Prevotella, Enterococcus and Akkermansia was significantly decreased, while the pathogenic bacteria Escherichia/Shigella were significantly increased in diarrhea rats. Taken together, the gut microbiota is closely associated with E. coli O₁₀₁-induced diarrhea in lower microbial diversity and dysbiosis of gut microbiota at different taxonomical levels.

Idiopathic Colitis in Rhesus Macaques Is Associated With Dysbiosis, Abundant Enterochromaffin Cells and Altered T-Cell Cytokine Expression

Idiopathic chronic diarrhea (ICD) is a common ailment affecting captive rhesus macaques ( Macaca mulatta). ICD cases are characterized by diarrhea in the absence of commonly identified diarrheal pathogens and multiple recurrences even after supportive therapy. Histologically, the disease is characterized by lymphoplasmacytic colitis. We identified 35 rhesus macaques euthanized for ICD during a 7-month period and described demographic, clinical, histologic, and immunologic commonalities. We found a trend of historic Campylobacter spp. and trichomonad infections. Furthermore, rhesus macaques with ICD demonstrated loss of normal colonic adherent bacterium, identified in this study as Helicobacter macacae; increased abundance of Pentatrichomonas hominis; and increased frequency of colonic serotonin-positive enterochromaffin cells. Interestingly, colonic and ileal T-helper cells of animals with ICD manifested decreased capacity for expression of certain cytokines, in particular interleukin (IL)-4 and IL-13. These data further describe a common ailment and suggest new avenues to identify complex interactions involved in the etiology of recurring diarrhea in young rhesus macaques.

Microscopic colitis in patients with ulcerative colitis or Crohn's disease: a retrospective observational study and review of the literature

OBJECTIVES

Onset of microscopic colitis (MC) in patients with ulcerative colitis (UC) or Crohn's disease (CD), or vice versa, has been reported occasionally but the subject is not well described. We therefore report a retrospective observational study of such patients and review the literature.

METHODS

Forty-six Swedish gastroenterology clinics were contacted about patients with diagnoses of both inflammatory bowel disease (IBD) and MC. Publications were searched on PubMed.

RESULTS

We identified 31 patients with onset of MC after a median (range) of 20 (2-52) years after diagnosis of IBD, or vice versa; 21 UC patients developed collagenous colitis (CC) (n = 16) or lymphocytic colitis (LC) (n = 5); nine CD patients developed CC (n = 5) or LC (n = 4); one CC patient developed CD. Of the 21 UC patients, 18 had extensive disease, whereas no consistent phenotype occurred in CD. Literature review revealed 27 comprehensive case reports of patients with diagnoses of both IBD and MC. Thirteen MC patients developed IBD, of which four required colectomy. Fourteen IBD patients later developed MC. There were incomplete clinical data in 115 additional reported patients.

CONCLUSIONS

Altogether 173 patients with occurrence of both IBD and MC were found. The most common finding in our patients was onset of CC in a patient with UC. Although these are likely random associations of two different disorders, MC should be considered in the patient with UC or CD if there is onset of chronic watery diarrhoea without endoscopic relapse of IBD.

Microscopic colitis-microbiome, barrier function and associated diseases

Microscopic colitis (MC) is a chronic inflammatory bowel disease (IBD) with little in terms of endoscopic abnormalities and is frequently associated with other autoimmune diseases. The peak incidence of the disease is in middle aged or older populations, mostly females. The pathogenesis of MC is complex, multifactorial and poorly understood. Current concepts revolve around innate immunity or microbiome alterations as well as gut barrier dysfunction, all of which lead to the development of subtle inflammatory lesions in gut mucosa. The results of numerous basic and clinical studies involving molecular techniques as well as advanced endoscopic imaging revealed the important role of both intrinsic (e.g., hormonal) as well as extrinsic (e.g., NSAIDs and PPIs) factors in the modulation of gastrointestinal microbiome and MC pathogenesis. Capsule endoscopy as well confocal endomicroscopy imaging, alongside standard endoscopic techniques offer new tools in the evaluation of MC patients and allow their better stratification for novel treatment protocols based on modulation of gut microbiome and barrier function.

Partial to complete abrogation of the subepithelial macrophage barrier against the gut microbiota in patients with ulcerative colitis and Crohn's colitis

AIMS

The integrity of the band of indigenous macrophages in the subepithelial layer of the lamina propria (SLP) is crucial in preventing the commensal gut microbiota from attacking the host. The breakdown of the SLP macrophage barrier results in microbiota inflow and improper immune responses; this might lead to inflammatory bowel disease (IBD). During inflammation, the SLP macrophage barrier is reinforced by inflammation-elicited macrophages (IEMs), which are derived from blood-circulating monocytes. The aim was to explore the characteristics of the SLP macrophage band in a cohort of biopsies without inflammation, in patients with ulcerative colitis in remission (UCre), and in patients with right-sided Crohn's colitis (RCC).

METHODS AND RESULTS

Endoscopic biopsies were taken from endoscopically normal descending colon in 247 patients; 80 with IBD (27 UCre and 53 RCC), and 167 without IBD [90 had colonic diarrhoea, 63 were enrolled in a colorectal cancer (CRC) surveillance programme, seven had microscopic colitis in remission, and seven had miscellaneous colonic ailments]. Sections showed no inflammatory changes; they were immunostained with CD68. Among patients with UCre and RCC, the SLP band of CD68+ macrophages was fragmented or minute in 59% (47/80) and negative in 9% (7/80). In contrast, only 31% (51/167) of the biopsies from control patients had a fragmented/minute SLP band of CD68+ macrophages, and none had a negative SLP band of CD68+ macrophages (IBD versus controls, P < 0.05).

CONCLUSIONS

The finding that the SLP macrophage barrier was fragmented to totally abrogated in UCre and RCC patients suggests a longlasting defect in the SLP CD68+ macrophage barrier in these patients. The lack of ongoing inflammation in colonic biopsies should rule out the participation of bone marrow-derived IEMs in the abrogation of the SLP macrophage barrier reported here.

Faecal microbiota transplantation in patients with Clostridium difficile and significant comorbidities as well as in patients with new indications: A case series

Fecal microbiota transplantation (FMT) is effective in recurrent Clostridium difficile infection (rCDI). Knowledge of the safety and efficacy of FMT treatment in immune deficient patients is scarce. FMT has been suggested as a potential method for an increasing number of new indications besides rCDI. Among our FMT-treated rCDI patients, we reviewed those with major comorbidities: two human immunodeficiency virus patients, six haemodialysis patients, two kidney transplant patients, two liver transplant patients and a patient with chronic lymphatic leukaemia. We also reviewed those treated with FMT for indications other than rCDI: Salmonella carriage (two patients), trimethylaminuria (two patients), small intestinal bacterial overgrowth (SIBO; one patient), and lymphocytic colitis (one patient), as well as a common variable immunodeficiency patient with chronic norovirus infection and ESBL-producing Escherichia coli (E. coli) carriage. Of the thirteen rCDI patients treated with FMT, eleven cleared the CDI. The observed adverse events were not directly attributable to FMT. Concerning the special indications, both Salmonellas and ESBL-producing E. coli were eradicated. One trimethylaminuria patient and one SIBO-patient reported a reduction of symptoms. Three patients did not experience a benefit from FMT: chronic norovirus, lymphocytic colitis and the other fish malodour syndrome. There were no reported side effects in this group. FMT appeared to be safe and effective for immunocompromised patients with rCDI. FMT showed promise for the eradication of antibiotic-resistant bacteria, but further research is warranted.

Early Life Exposure, Lifestyle, and Comorbidity as Risk Factors for Microscopic Colitis: A Case-Control Study

BACKGROUND

The pathophysiology of microscopic colitis (MC) is not fully understood. A dysregulation of the adaptive immune response has been hypothesized, of which the maturation and function is imprinted in early life. Various other factors (e.g., hormonal factors) have also been found to be associated, sometimes, with minimal or conflicting evidence. The aims of this study were to evaluate whether an exposure to (microbial) agents in early life might be protective for MC development and to assess the role of several less well-established risk factors in one study.

METHODS

A case-control study was conducted including MC cases diagnosed in the Southern part of the Netherlands between 2000 and 2012. Cases were matched to non-MC controls from the same area, based on gender and year of birth, and assigned the same index date. All subjects filled out the same study questionnaire on various risk factors.

RESULTS

In total, 171 MC cases and 361 controls were included. In the multivariable logistic regression analysis, current smoking (odds ratio 6.23, 95% confidence interval, 3.10-12.49), arthrosis, and a cardiac disorder were associated with MC. No association was observed, for example, factors related to early life exposure to microbial antigens, passive smoking, rheumatoid arthritis, celiac disease, or hormonal factors.

CONCLUSIONS

Early life exposure to microbial antigens and increased hormonal exposure were not found to be protective for MC. Current smoking seems to be an incontestable risk factor for MC. Therefore, exposure to environmental risk factors later may be of relevance in MC pathogenesis and warrants further investigation.

Prebiotics and synbiotics in ulcerative colitis

BACKGROUND

Ulcerative colitis (UC) is a chronic inflammatory disease of the colon with unclear pathogenesis. A dysbiotic intestinal microbiota is regarded as a key component in the disease process and there has been significant interest in developing new treatments which target the microbiota.

AIM

To give an overview of the studies to date investigating prebiotics and synbiotics for the treatment of UC.

METHODS

A literature search of PubMed and related search engines was carried out using the terms "ulcerative colitis" in combination with "prebiotic", "synbiotic" or "dietary fibre".

RESULTS

In total 17 studies on humans examining the effect of prebiotics in UC were found. Five major groups could be distinguished. Fructo-oligosaccharides were tried in six studies (mean 35 patients included, range 9-121). One study found a clinical response while two demonstrated indirect evidence of an effect. Germinated barley foodstuff was used in 8 studies (mean 38 patients, range 10-63). One study found an endoscopic response, while four noted a clinical response and two some indirect effects. Galacto-oligosaccharides, lactulose and resveratrol were used in one study each (mean 48 patients, range 41-52). One study found an endoscopic response and one a clinical response.

CONCLUSION

There is yet inadequate evidence - especially in humans - to support any particular prebiotic in the clinical management of UC. However, due to the bulk of evidence supporting the effect of the microbiota on colonic inflammation, there is enough potential to justify further high-quality clinical trials investigating this subject.

Clinical and immunologic effects of faecal microbiota transplantation in a patient with collagenous colitis

One to six percent of patients with microscopic colitis are refractory to medical treatment. The effect of faecal microbiota transplantation (FMT) in active collagenous colitis (CC) has, to the best of our knowledge, never been reported before. Here, we report the effect of repeated FMT in a patient with CC. The patient presented with severe symptoms including profuse diarrhea and profound weight loss. Although she responded to budesonide in the beginning, she became gradually refractory to medical treatment, and was therefore treated with FMT. The patient remained in remission for 11 mo after the third faecal transplantation. The immunomodulatory effect of the therapy was evaluated using flow cytometry, which showed alterations in the profile of intraepithelial and lamina propria lymphocyte subsets after the second transplantation. Our observations indicate that FMT can have an effect in CC, which support the hypothesis that luminal factors, influencing the intestinal microbiota, are involved in the pathogenesis of CC.

Diagnosis and Management of Microscopic Colitis

Microscopic colitis (MC) is a relatively common cause of chronic watery diarrhea, especially in older persons. Associated symptoms, including abdominal pain and arthralgias, are common. The diagnosis is based upon characteristic histological findings in the presence of diarrhea. The two types of MC, collagenous and lymphocytic colitis, share similar clinical features, with the main difference being the presence or absence of a thickened subepithelial collagen band. There are several treatment options for patients with MC, although only budesonide has been well studied in multiple controlled clinical trials. This review will describe the clinical features, epidemiology, pathophysiology, diagnostic criteria, and treatment of patients with MC.

Regional Specialisation of T Cell Subsets and Apoptosis in the Human Gut Mucosa: Differences Between Ileum and Colon in Healthy Intestine and Inflammatory Bowel Diseases

BACKGROUND AND AIMS

There is very limited information regarding region-specific immunological response in human intestine. We aimed to determine differences in immune compartmentalisation between ileum and colon in healthy and inflamed mucosa.

METHODS

T cell profile and its apoptosis were measured by flow cytometry, Th1, Th17, Treg [CD4(+)CD25(+)FOXP3(+)], double positive [DP, CD3(+)CD4(+)CD8(+)] and double negative T cells [DN, CD3(+)CD4(-)CD8(-)], immunohistochemistry [FOXP3, caspase-3], and real-time polymerase chain reaction [PCR] [IFN-γ, IL-17-A, and FOXP3] on biopsies from different regions of healthy intestine and of intestine in inflammatory bowel diseases.

RESULTS

Healthy colon showed higher percentages of Treg, Th17, and DN, and lower numbers of DP T cells compared with ileum [p < 0.05]. Some but not all region-specific differences were lost in inflammatory conditions. Disease-specific patterns were found: a Th1/Th17 pattern and a Th17 pattern in Crohn's disease and ulcerative colitis respectively, whereas a reduction in Th1/Th17 was found in microscopic colitis. In colonic Crohn's disease and microscopic colitis, DN T cells had a pattern inverse to that of Th1/Th17 (increase in microscopic colitis [p < 0.05] and decrease in Crohn's disease [p < 0.005]). Higher levels of lymphocyte apoptosis were found in healthy colon compared with the ileal counterparts [p = 0.001]. All forms of colonic inflammation presented a dramatic decrease in apoptosis compared with healthy colon. By contrast ileal Crohn's disease showed higher levels of cleaved-Caspase(+) CD3(+) cells.

CONCLUSIONS

Immunological differences exist in healthy gastrointestinal tract. Inflammatory processes overwhelm some location-specific differences, whereas others are maintained. Care has to be taken when analysing immune response in intestinal inflammation, as location-specific differences may be relevant.

The association between the intake of specific dietary components and lifestyle factors and microscopic colitis

Background/Objectives:

The incidence of microscopic colitis (MC) has increased over the previous decades. In addition to smoking and drugs, currently unidentified environmental factors may have a role. The aim of this study was to determine whether specific dietary or other lifestyle factors were associated with the development of MC.

Subject/Methods:

The population-based cohort Malmö Diet and Cancer Study of 28 095 individuals was examined. Information about dietary habits was collected by a modified diet history method. Data on anthropometry were measured, and socio-economic and lifestyle factors were collected by questionnaires. Cases of MC were identified in medical registers. Associations were estimated using Cox regression analysis.

Results:

During a 22-year period, 135 patients were diagnosed with MC. Intakes of protein, carbohydrates, sucrose, saturated fat, monounsaturated fat, polyunsaturated fat, omega-3 or omega-6 fatty acids, fibre and zinc were not associated with MC. We could verify the previously reported association between MC and smoking (hazard ratio (HR): 2.29; 95% confidence interval (CI): 1.66–3.84) and the female gender (HR: 3.57; 95% CI: 2.22–5.74). High alcohol consumption was associated with an increased risk for MC (HR: 1.89 for the highest quartile; 95% CI: 0.82–4.33, P for trend=0.032). In a post hoc analysis, alcohol intake including all patients independently of consumption seemed to reduce the smoking-related risk.

Conclusions:

Despite a large cohort and a long follow-up period, we could not detect any dietary risk factors for MC. The aetiological mechanisms behind the positive impact of smoking and alcohol on MC risk should be investigated.