Microscopic Colitis and Celiac Disease: Sharing More than a Diagnostic Overlap.

Microscopic colitis (MC) is an emergent group of chronic inflammatory diseases of the colon, and celiac disease (CD) is a chronic gluten-induced immune-mediated enteropathy affecting the small bowel. We performed a narrative review to provide an overview regarding the relationship between both disorders, analyzing the most recent studies published at the epidemiological, clinical and pathophysiological levels. In fact, MC and CD are concomitantly prevalent in approximately 6% of the cases, mainly in the subset of refractory patients. Thus, physicians should screen refractory patients with CD against MC and vice versa. Both disorders share more than a simple epidemiological association, being multifactorial diseases involving innate and adaptive immune responses to known or unknown luminal factors based on a rather common genetic ground. Moreover, autoimmunity is a shared characteristic between the patients with MC and those with CD, with autoimmunity in the latter being quite well-established. Furthermore, CD and MC share some common clinical symptoms and risk factors and overlap with other gastrointestinal diseases, but some differences exist between both disorders. More studies are therefore needed to better understand the complex mechanisms involving the common pathogenetic ground contributing to the CD and MC epidemiological association.

Determinant factors for first-line treatment choice and effectiveness in pediatric eosinophilic esophagitis: an analysis of the EUREOS EoE CONNECT registry.

This study compared short-term effectiveness of proton pump inhibitors (PPI), swallowed topical corticosteroids (STC), and dietary therapies in reversing clinical and histological features in pediatric patients with eosinophilic esophagitits (EoE). Determinants for treatment choice and PPI therapy effectiveness were also assessed.  A cross-sectional study analysis of patients under 18 years old recruited onto the multicenter EoE CONNECT registry was performed. Clinico-histological response was defined as symptomatic improvement plus a peak eosinophil count below 15 per high-power field after treatment. Effectiveness of first-line options used in monotherapy was compared. Overall, 393 patients (64% adolescents) receiving PPI, STC, or dietary monotherapy to induce EoE remission were identified. PPI was the preferred option (71.5%), despite STC providing the highest clinico-histological response rates (66%) compared to PPI (44%) and diet (42%). Logistic regression identified fibrotic features and recruitment at Italian sites independently associated to first-line STC treatment; age under 12 associated to dietary therapy over other options. Analysis of 262 patients in whom PPI effectiveness was evaluated after median (IQR) 96 (70-145) days showed that this effectiveness was significantly associated with management at pediatric facilities and use of high PPI doses. Among PPI responders, decrease in rings and structures in endoscopy from baseline was documented, with EREFS fibrotic subscore for rings also decreasing among responders (0.27 ± 0.63 vs. 0.05 ± 0.22, p < 0.001). Conclusion: Initial therapy choice for EoE depends on endoscopic phenotype, patient's age, and patients' origin. High PPI doses and treatment in pediatric facilities significantly determined effectiveness, and reversed fibrotic endoscopic features among responders. What is Known: • Proton pump inhibitors are widely used to induce and maintain remission in EoE in real practice, despite other first-line alternative therapies possibly providing higher effectiveness. What is New: • Proton pump inhibitors represent up to two-thirds of first-line monotherapies used to induce EoE remission in pediatric and adolescent patients with EoE. The choice of STC as first-line treatment for EoE was significantly associated with fibrotic features at baseline endoscopy and recruitment in Italian centers; age less than 12 years was associated with dietary therapy. • PPI effectiveness was found to be determined by use of high doses, attendance at pediatric facilities, presenting inflammatory instead of fibrotic or mixed phenotypes, and younger age. Among responders, PPI therapy reversed both inflammatory and fibrotic features of EoE after short-term treatment.

Swallowed topical corticosteroids for eosinophilic esophagitis: Utilization and real-world efficacy from the EoE CONNECT registry.

BACKGROUND: Swallowed topical corticosteroids (tC) are common therapy for patients with eosinophilic esophagitis (EoE). Widely heterogeneous results have occurred due to their active ingredients, formulations and doses. OBJECTIVE: To assess the effectiveness of topical corticosteroid therapy for EoE in real-world practice. METHODS: Cross-sectional study analysis of the multicentre EoE CONNECT registry. Clinical remission was defined as a decrease of ≥50% in dysphagia symptom scores; histological remission was defined as a peak eosinophil count below 15 per high-power field. The effectiveness in achieving clinico-histological remission (CHR) was compared for the main tC formulations. RESULTS: Overall, data on 1456 prescriptions of tC in monotherapy used in 866 individual patients were assessed. Of those, 904 prescriptions with data on formulation were employed for the induction of remission; 234 reduced a previously effective dose for maintenance. Fluticasone propionate formulations dominated the first-line treatment, while budesonide was more common in later therapies. A swallowed nasal drop suspension was the most common formulation of fluticasone propionate. Doses ≥0.8 mg/day provided a 65% CHR rate and were superior to lower doses. Oral viscous solution prepared by a pharmacist was the most common prescription of budesonide; 4 mg/day provided no benefit over 2 mg/day (CHR rated being 72% and 80%, respectively). A multivariate analysis revealed budesonide orodispersible tablets as the most effective therapy (OR 18.9, p < 0.001); use of higher doses (OR 4.3, p = 0.03) and lower symptom scores (OR 0.9, p = 0.01) were also determinants of effectiveness. CONCLUSION: Reduced symptom severity, use of high doses, and use of budesonide orodispersible tablets particularly were all independent predictors of tC effectiveness.

Human Leukocyte Antigen Signatures as Pathophysiological Discriminants of Microscopic Colitis Subtypes.

BACKGROUND AND AIMS: Microscopic colitis [MC] is currently regarded as an inflammatory bowel disease that manifests as two subtypes: collagenous colitis [CC] and lymphocytic colitis [LC]. Whether these represent a clinical continuum or distinct entities is, however, an open question. Genetic investigations may contribute important insight into their respective pathophysiologies. METHODS: We conducted a genome-wide association study [GWAS] meta-analysis in 1498 CC, 373 LC patients, and 13 487 controls from Europe and the USA, combined with publicly available MC GWAS data from UK Biobank and FinnGen [2599 MC cases and 552 343 controls in total]. Human leukocyte antigen [HLA] alleles and polymorphic residues were imputed and tested for association, including conditional analyses for the identification of key causative variants and residues. Genetic correlations with other traits and diagnoses were also studied. RESULTS: We detected strong HLA association with CC, and conditional analyses highlighted the DRB1*03:01 allele and its residues Y26, N77, and R74 as key to this association (best p = 1.4 × 10-23, odds ratio [OR] = 1.96). Nominally significant genetic correlations were detected between CC and pneumonia [rg = 0.77; p = 0.048] and oesophageal diseases [rg = 0.45, p = 0.023]. An additional locus was identified in MC GWAS analyses near the CLEC16A and RMI2 genes on chromosome 16 [rs35099084, p = 2.0 × 10-8, OR = 1.31]. No significant association was detected for LC. CONCLUSION: Our results suggest CC and LC have distinct pathophysiological underpinnings, characterised by an HLA predisposing role only in CC. This challenges existing classifications, eventually calling for a re-evaluation of the utility of MC umbrella definitions.

Acute Stress Regulates Sex-Related Molecular Responses in the Human Jejunal Mucosa: Implications for Irritable Bowel Syndrome.

Irritable bowel syndrome (IBS) is a prevalent gastrointestinal disorder linked to intestinal barrier dysfunction and life stress. We have previously reported that female sex per se determines an increased susceptibility to intestinal barrier dysfunction after cold pain stress (CPS). We aimed to identify sex-related molecular differences in response to CPS in healthy subjects to understand the origin of sex bias predominance in IBS. In 13 healthy males and 21 females, two consecutive jejunal biopsies were obtained using Watson's capsule, at baseline, and ninety minutes after CPS. Total mucosal RNA and protein were isolated from jejunal biopsies. Expression of genes related to epithelial barrier (CLDN1, CLDN2, OCLN, ZO-1, and ZO-3), mast cell (MC) activation (TPSAB1, SERPINA1), and the glucocorticoid receptor (NR3C1) were analyzed using RT-qPCR. NR3C1, ZO-1 and OCLN protein expression were evaluated through immunohistochemistry and western blot, and mucosal inflammation through MC, lymphocyte, and eosinophil numbering. Autonomic, hormonal, and psychological responses to CPS were monitored. We found an increase in jejunal MCs, a reduced CLDN1 and OCLN expression, and an increased CLDN2 and SERPINA1 expression 90 min after CPS. We also found a significant decrease in ZO-1, OCLN, and NR3C1 gene expression, and a decrease in OCLN protein expression only in females, when compared to males. CPS induced a significant increase in blood pressure, plasma cortisol and ACTH, and subjective stress perception in all participants. Specific and independent sex-related molecular responses in epithelial barrier regulation are unraveled by acute stress in the jejunum of healthy subjects and may partially explain female predominance in IBS.

Differences between childhood- and adulthood-onset eosinophilic esophagitis: An analysis from the EoE connect registry.

BACKGROUND: Direct comparisons of childhood- and adulthood-onset eosinophilic esophagitis (EoE) are scarce. AIM: To compare disease characteristics, endoscopic and histological features, allergic concomitances and therapeutic choices across ages. METHODS: Cross-sectional analysis of the EoE CONNECT registry. RESULTS: The adulthood-onset cohort (those diagnosed at ≥18y) comprised 1044 patients and the childhood-onset cohort (patients diagnosed at <18 y), 254. Vomiting, nausea, chest and abdominal pain, weight loss, slow eating and food aversion were significantly more frequent in children; dysphagia, food bolus impaction and heartburn predominated in adults. A family history of EoE was present in 16% of pediatric and 8.2% of adult patients (p<0.001). Concomitant atopic diseases did not vary across ages. Median±IQR diagnostic delay (years) from symptom onset was higher in adults (2.7 ± 6.1) than in children (1 ± 2.1; p<0.001). Esophageal strictures and rings predominated in adults (p<0.001), who underwent esophageal dilation more commonly (p = 0.011). Inflammatory EoE phenotypes were more common in children (p = 0.001), who also presented higher eosinophil counts in biopsies (p = 0.015) and EREFS scores (p = 0.017). Despite PPI predominating as initial therapy in all cohorts, dietary therapy and swallowed topical corticosteroids were more frequently prescribed in children (p<0.001). CONCLUSIONS: Childhood-onset EoE has differential characteristics compared with adulthood-onset, but similar response to treatment.

Mucosal Plasma Cell Activation and Proximity to Nerve Fibres Are Associated with Glycocalyx Reduction in Diarrhoea-Predominant Irritable Bowel Syndrome: Jejunal Barrier Alterations Underlying Clinical Manifestations.

Irritable bowel syndrome (IBS) is a disorder of brain-gut interaction characterised by abdominal pain and changes in bowel habits. In the diarrhoea subtype (IBS-D), altered epithelial barrier and mucosal immune activation are associated with clinical manifestations. We aimed to further evaluate plasma cells and epithelial integrity to gain understanding of IBS-D pathophysiology. One mucosal jejunal biopsy and one stool sample were obtained from healthy controls and IBS-D patients. Gastrointestinal symptoms, stress, and depression scores were recorded. In the jejunal mucosa, RNAseq and gene set enrichment analyses were performed. A morphometric analysis by electron microscopy quantified plasma cell activation and proximity to enteric nerves and glycocalyx thickness. Immunoglobulins concentration was assessed in the stool. IBS-D patients showed differential expression of humoral pathways compared to controls. Activation and proximity of plasma cells to nerves and IgG concentration were also higher in IBS-D. Glycocalyx thickness was lower in IBS-D compared to controls, and this reduction correlated with plasma cell activation, proximity to nerves, and clinical symptoms. These results support humoral activity and loss of epithelial integrity as important contributors to gut dysfunction and clinical manifestations in IBS-D. Additional studies are needed to identify the triggers of these alterations to better define IBS-D pathophysiology.

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.

Accurate and timely diagnosis of Eosinophilic Esophagitis improves over time in Europe. An analysis of the EoE CONNECT Registry.

BACKGROUND: Poor adherence to clinical practice guidelines for eosinophilic esophagitis (EoE) has been described and the diagnostic delay of the disease continues to be unacceptable in many settings. OBJECTIVE: To analyze the impact of improved knowledge provided by the successive international clinical practice guidelines on reducing diagnostic delay and improving the diagnostic process for European patients with EoE. METHODS: Cross-sectional analysis of the EoE CONNECT registry based on clinical practice. Time periods defined by the publication dates of four major sets of guidelines over 10 years were considered. Patients were grouped per time period according to date of symptom onset. RESULTS: Data from 1,132 patients was analyzed and median (IQR) diagnostic delay in the whole series was 2.1 (0.7-6.2) years. This gradually decreased over time with subsequent release of new guidelines (p < 0.001), from 12.7 years up to 2007 to 0.7 years after 2017. The proportion of patients with stricturing of mixed phenotypes at the point of EoE diagnosis also decreased over time (41.3% vs. 16%; p < 0.001), as did EREFS scores. The fibrotic sub-score decreased from a median (IQR) of 2 (1-2) to 0 (0-1) when patients whose symptoms started up to 2007 and after 2017 were compared (p < 0.001). In parallel, symptoms measured with the Dysphagia Symptoms Score reduced significantly when patients with symptoms starting before 2007 and after 2012 were compared. A reduction in the number of endoscopies patients underwent before the one that achieved an EoE diagnosis, and the use of allergy testing as part of the diagnostic workout of EoE, also reduced significantly over time (p = 0.010 and p < 0.001, respectively). CONCLUSION: The diagnostic work-up of EoE patients improved substantially over time at the European sites contributing to EoE CONNECT, with a dramatic reduction in diagnostic delay.

EoE CONNECT, the European Registry of Clinical, Environmental, and Genetic Determinants in Eosinophilic Esophagitis: rationale, design, and study protocol of a large-scale epidemiological study in Europe.

BACKGROUND: The growing prevalence of eosinophilic esophagitis (EoE) represents a considerable burden to patients and health care systems. Optimizing cost-effective management and identifying mechanisms for disease onset and progression are required. However, the paucity of large patient cohorts and heterogeneity of practice hinder the defining of optimal management of EoE. METHODS: EoE CONNECT is an ongoing, prospective registry study initiated in 2016 and currently managed by EUREOS, the European Consortium for Eosinophilic Diseases of the Gastrointestinal Tract. Patients are managed and treated by their responsible specialists independently. Data recorded using a web-based system include demographic and clinical variables; patient allergies; environmental, intrapartum, and early life exposures; and family background. Symptoms are structurally assessed at every visit; endoscopic features and histological findings are recorded for each examination. Prospective treatment data are registered sequentially, with new sequences created each time a different treatment (active principle, formulation, or dose) is administered to a patient. EoE CONNECT database is actively monitored to ensure the highest data accuracy and the highest scientific and ethical standards. RESULTS: EoE CONNECT is currently being conducted at 39 centers in Europe and enrolls patients of all ages with EoE. In its aim to increase knowledge, to date EoE CONNECT has provided evidence on the effectiveness of first- and second-line therapies for EoE in clinical practice, the ability of proton pump inhibitors to induce disease remission, and factors associated with improved response. Drug effects to reverse fibrous remodeling and endoscopic features of fibrosis in EoE have also been assessed. CONCLUSION: This prospective registry study will provide important information on the epidemiological and clinical aspects of EoE and evidence as to the real-world and long-term effectiveness and safety of therapy. These data will potentially be a vital benchmark for planning future EoE health care services in Europe.

The Process of Developing a Disease Activity Index in Microscopic Colitis.

BACKGROUND AND AIMS: Patient-reported outcome measures [PROMs] aim to measure patients' perception of how their disorder influences everyday functioning. The objective of this study was to develop a PROM to assess disease activity in microscopic colitis [MC] fulfilling the requirements of the Food and Drug Administration [FDA]. METHODS: The European Microscopic Colitis Activity Index [E-MCAI] was developed in four steps. [1] A list of symptoms associated with active MC was created by a group of experts in the field. [2] Content validity of the symptoms was performed by experts [n = 14] and patients [n = 79] using the Content Validity Index. [3] Questions and response alternatives were created for each symptom, and validity of the E-MCAI was evaluated with cognitive interviews with patients [n = 7] and by the experts. [4] A pilot postal survey was performed to ensure usability. RESULTS: Seven of the symptoms related to active MC fulfilled the criteria for content validity and were included in the E-MCAI: stool consistency, stool frequency, stools at night, feel a need to pass more stools shortly after a bowel movement, urgent need to empty the bowel, leakage of stool and abdominal pain. The development and validation process resulted in the current version of the E-MCAI consisting of six questions related to MC. CONCLUSIONS: The E-MCAI was developed using the methods advocated by the FDA. The evaluation indicates good content validity. Further evaluation will be performed to achieve construct validity, reliability and responsiveness in future cross-sectional and longitudinal studies.

The Intestinal Gas Questionnaire (IGQ): Psychometric validation of a new instrument for measuring gas-related symptoms and their impact on daily life among general population and irritable bowel syndrome.

BACKGROUND: Gas-related symptoms (GRS) are common in the general population (GPop) and among patients with disorders of gut-brain interactions but there is no patient-reported outcome evaluating these symptoms and their impact on daily life. We have previously developed a 43-item intestinal gas questionnaire (IGQ). The aim of the present study is to perform a psychometric validation of this instrument. METHODS: Participants (119 from the GPop and 186 irritable bowel syndrome (IBS) patients) were recruited from 3 countries (UK, Spain, France). IBS patients fulfilled ROME IV criteria with an IBS severity score between 150 and 300. Participants completed the IGQ, the functional Digestive Disorders Quality of Life (FDDQL), and the EQ-5D. A subgroup (n = 90) repeated the IGQ completion after 7 days on paper or electronically. RESULTS: From the original IGQ questionnaire, 26 items were deleted because of poor performance. Confirmatory factorial analysis on the remaining 17 items (7 symptom and 10 impact items) yielded a 6-factor structure accounting for 67% of the variance for bloating (6 items), flatulence (3), belching (2), bad breath (2), stomach rumbling (2), and difficult gas evacuation (2). Global score (0-100) was worse among IBS vs GPop (40 ± 15 vs 33 ± 17; p = 0.0016). At the second visit, the intraclass correlation coefficient of IGQ scores was between 0.71 and 0.86 (n = 67) for test-retest reliability and 0.61-0.87 (n = 64) for equivalence between electronic and paper versions of IGQ. CONCLUSION: The IGQ available in paper and electronic versions in 3 languages is a robust instrument for capturing and measuring GRS and their impact on daily life.

Present and Future Therapeutic Approaches to Barrier Dysfunction.

There is converging and increasing evidence, but also uncertainty, for the role of abnormal intestinal epithelial barrier function in the origin and development of a growing number of human gastrointestinal and extraintestinal inflammatory disorders, and their related complaints. Despite a vast literature addressing factors and mechanisms underlying changes in intestinal permeability in humans, and its connection to the appearance and severity of clinical symptoms, the ultimate link remains to be established in many cases. Accordingly, there are no directives or clinical guidelines related to the therapeutic management of intestinal permeability disorders that allow health professionals involved in the management of these patients to carry out a consensus treatment based on clinical evidence. Instead, there are multiple pseudoscientific approaches and commercial propaganda scattered on the internet that confuse those affected and health professionals and that often lack scientific rigor. Therefore, in this review we aim to shed light on the different therapeutic options, which include, among others, dietary management, nutraceuticals and medical devices, microbiota and drugs, and epigenetic and exosomes-manipulation, through an objective evaluation of the scientific publications in this field. Advances in the knowledge and management of intestinal permeability will sure enable better options of dealing with this group of common disorders to enhance quality of life of those affected.

Proton pump inhibitor therapy reverses endoscopic features of fibrosis in eosinophilic esophagitis.

BACKGROUND: Long-standing inflammation leads to esophageal remodeling with stricture formation in patients with eosinophilic esophagitis (EoE). The ability of proton pump inhibitors (PPI) to reverse endoscopic features of fibrosis is still unknown. OBJECTIVE: To investigate the effect of a short course of PPI treatment in reducing endoscopic findings indicative of esophageal fibrosis in EoE patients. METHODS: Cross-sectional analysis of the EoE CONNECT registry. Patients who received PPI to induce EoE remission were evaluated. Endoscopic features were graded using the EoE Endoscopic Reference Score (EREFS), with rings and strictures indicating fibrosis. Results were compared to those from patients treated with swallowed topic corticosteroids (STC). RESULTS: Clinico-histological remission was achieved in 83/166 adult patients treated with PPI (50%) and in 65/79 (82%) treated with STC; among responders, 60 (36%) and 57 (72%) patients respectively achieved deep histological remission (<5 eosinophils/hpf). At baseline, mean±SD EREFS was lower in patients treated with PPI compared to those who received STC (p < 0.001). Short term treatment significantly reduced EREFS scores in patients treated either with PPI or STC as well as rings and strictures. Among patients treated with PPI, deep histological remission (<5 eosinophils/hpf) provided further reduction in total EREFS score. CONCLUSION: Effective PPI therapy for EoE significantly reduced endoscopic esophageal fibrosis in the short term.

Histological disease activity in patients with microscopic colitis is not related to clinical disease activity or long-term prognosis.

BACKGROUND: Microscopic colitis (MC) is a common cause of chronic watery diarrhea. Biopsies with characteristic histological features are crucial for establishing the diagnosis. The two main subtypes are collagenous colitis (CC) and lymphocytic colitis (LC) but incomplete forms exist. The disease course remains unpredictable varying from spontaneous remission to a relapsing course. AIM: To identify possible histological predictors of course of disease. METHODS: Sixty patients from the European prospective MC registry (PRO-MC Collaboration) were included. Digitised histological slides stained with CD3 and Van Gieson were available for all patients. Total cell density and proportion of CD3 positive lymphocytes in lamina propria and surface epithelium were estimated by automated image analysis, and measurement of the subepithelial collagenous band was performed. Histopathological features were correlated to the number of daily stools and daily watery stools at time of endoscopy and at baseline as well as the clinical disease course (quiescent, achieved remission after treatment, relapsing or chronic active) at 1-year follow-up. RESULTS: Neither total cell density in lamina propria, proportion of CD3 positive lymphocytes in lamina propria or surface epithelium, or thickness of collagenous band showed significant correlation to the number of daily stools or daily watery stools at any point of time. None of the assessed histological parameters at initial diagnosis were able to predict clinical disease course at 1-year follow-up. CONCLUSIONS: Our data indicate that the evaluated histological parameters were neither markers of disease activity at the time of diagnosis nor predictors of disease course.

European guidelines on microscopic colitis: United European Gastroenterology and European Microscopic Colitis Group statements and recommendations.

INTRODUCTION: Microscopic colitis is a chronic inflammatory bowel disease characterised by normal or almost normal endoscopic appearance of the colon, chronic watery, nonbloody diarrhoea and distinct histological abnormalities, which identify three histological subtypes, the collagenous colitis, the lymphocytic colitis and the incomplete microscopic colitis. With ongoing uncertainties and new developments in the clinical management of microscopic colitis, there is a need for evidence-based guidelines to improve the medical care of patients suffering from this disorder. METHODS: Guidelines were developed by members from the European Microscopic Colitis Group and United European Gastroenterology in accordance with the Appraisal of Guidelines for Research and Evaluation II instrument. Following a systematic literature review, the Grading of Recommendations Assessment, Development and Evaluation methodology was used to assess the certainty of the evidence. Statements and recommendations were developed by working groups consisting of gastroenterologists, pathologists and basic scientists, and voted upon using the Delphi method. RESULTS: These guidelines provide information on epidemiology and risk factors of microscopic colitis, as well as evidence-based statements and recommendations on diagnostic criteria and treatment options, including oral budesonide, bile acid binders, immunomodulators and biologics. Recommendations on the clinical management of microscopic colitis are provided based on evidence, expert opinion and best clinical practice. CONCLUSION: These guidelines may support clinicians worldwide to improve the clinical management of patients with microscopic colitis.

Course of Disease in Patients with Microscopic Colitis: A European Prospective Incident Cohort Study.

BACKGROUND AND AIMS: The disease course of microscopic colitis [MC] is considered chronic but benign. However, this assumption is based on mainly retrospective studies, reporting on incomplete follow-up of selective cohorts. Systematic, prospective and unbiased data to inform patients and healthcare professionals on the expected course of the disease and real-life response to therapy are warranted. METHODS: A prospective, pan-European, multi-centre, web-based registry was established. Incident cases of MC were included. Data on patient characteristics, symptoms, treatment and quality of life were systematically registered at baseline and during real-time follow-up. Four disease course phenotypes were discriminated and described. RESULTS: Among 381 cases with complete 1-year follow-up, 49% had a chronic active or relapsing disease course, 40% achieved sustained remission after treatment and 11% had a quiescent course. In general, symptoms and quality of life improved after 3 months of follow-up. A relapsing or chronic active disease course was associated with significantly more symptoms and impaired quality of life after 1 year. CONCLUSIONS: A minority of MC patients follow a quiescent disease course with spontaneous clinical improvement, whereas the majority suffer a chronic active or relapsing disease course during the first year after diagnosis, with persisting symptoms accompanied by a significantly impaired quality of life.

Overexpression of corticotropin-releasing factor in intestinal mucosal eosinophils is associated with clinical severity in Diarrhea-Predominant Irritable Bowel Syndrome.

Corticotropin-releasing factor (CRF) has been identified in intestinal mucosal eosinophils and associated with psychological stress and gut dysfunction. Irritable bowel syndrome (IBS) is commonly characterized by altered intestinal motility, immune activation, and increased gut barrier permeability along with heightened susceptibility to psychosocial stress. Despite intensive research, the role of mucosal eosinophils in stress-associated gut dysfunction remains uncertain. In this study, we evaluated eosinophil activation profile and CRF content in the jejunal mucosa of diarrhea-predominant IBS (IBS-D) and healthy controls (HC) by gene/protein expression and transmission electron microscopy. We also explored the association between intestinal eosinophil CRF and chronic stress, and the potential mechanisms underlying the stress response by assessing eosinophil response to neuropeptides. We found that mucosal eosinophils displayed higher degranulation profile in IBS-D as compared to HC, with increased content of CRF in the cytoplasmic granules, which significantly correlated with IBS clinical severity, life stress background and depression. Eosinophils responded to substance P and carbachol by increasing secretory activity and CRF synthesis and release, without promoting pro-inflammatory activity, a profile similar to that found in mucosal eosinophils from IBS-D. Collectively, our results suggest that intestinal mucosal eosinophils are potential contributors to stress-mediated gut dysfunction through CRF production and release.