Pain Severity Correlates With Biopsy-Mediated Colonic Afferent Activation But Not Psychological Scores in Patients With IBS-D.

INTRODUCTION: Despite heterogeneity, an increased prevalence of psychological comorbidity and an altered pronociceptive gut microenvironment have repeatedly emerged as causative pathophysiology in patients with irritable bowel syndrome (IBS). Our aim was to study these phenomena by comparing gut-related symptoms, psychological scores, and biopsy samples generated from a detailed diarrhea-predominant IBS patient (IBS-D) cohort before their entry into a previously reported clinical trial. METHODS: Data were generated from 42 patients with IBS-D who completed a daily 2-week bowel symptom diary, the Hospital Anxiety and Depression score, and the Patient Health Questionnaire-12 Somatic Symptom score and underwent unprepared flexible sigmoidoscopy. Sigmoid mucosal biopsies were separately evaluated using immunohistochemistry and culture supernatants to determine cellularity, mediator levels, and ability to stimulate colonic afferent activity. RESULTS: Pain severity scores significantly correlated with the daily duration of pain (r = 0.67, P < 0.00001), urgency (r = 0.57, P < 0.0005), and bloating (r = 0.39, P < 0.05), but not with psychological symptom scores for anxiety, depression, or somatization. Furthermore, pain severity scores from individual patients with IBS-D were significantly correlated (r = 0.40, P < 0.008) with stimulation of colonic afferent activation mediated by their biopsy supernatant, but not with biopsy cell counts nor measured mediator levels. DISCUSSION: Peripheral pronociceptive changes in the bowel seem more important than psychological factors in determining pain severity within a tightly phenotyped cohort of patients with IBS-D. No individual mediator was identified as the cause of this pronociceptive change, suggesting that nerve targeting therapeutic approaches may be more successful than mediator-driven approaches for the treatment of pain in IBS-D

Pain Severity Correlates With Biopsy-Mediated Colonic Afferent Activation But Not Psychological Scores in Patients With IBS-D.

INTRODUCTION: Despite heterogeneity, an increased prevalence of psychological comorbidity and an altered pronociceptive gut microenvironment have repeatedly emerged as causative pathophysiology in patients with irritable bowel syndrome (IBS). Our aim was to study these phenomena by comparing gut-related symptoms, psychological scores, and biopsy samples generated from a detailed diarrhea-predominant IBS patient (IBS-D) cohort before their entry into a previously reported clinical trial. METHODS: Data were generated from 42 patients with IBS-D who completed a daily 2-week bowel symptom diary, the Hospital Anxiety and Depression score, and the Patient Health Questionnaire-12 Somatic Symptom score and underwent unprepared flexible sigmoidoscopy. Sigmoid mucosal biopsies were separately evaluated using immunohistochemistry and culture supernatants to determine cellularity, mediator levels, and ability to stimulate colonic afferent activity. RESULTS: Pain severity scores significantly correlated with the daily duration of pain (r = 0.67, P < 0.00001), urgency (r = 0.57, P < 0.0005), and bloating (r = 0.39, P < 0.05), but not with psychological symptom scores for anxiety, depression, or somatization. Furthermore, pain severity scores from individual patients with IBS-D were significantly correlated (r = 0.40, P < 0.008) with stimulation of colonic afferent activation mediated by their biopsy supernatant, but not with biopsy cell counts nor measured mediator levels. DISCUSSION: Peripheral pronociceptive changes in the bowel seem more important than psychological factors in determining pain severity within a tightly phenotyped cohort of patients with IBS-D. No individual mediator was identified as the cause of this pronociceptive change, suggesting that nerve targeting therapeutic approaches may be more successful than mediator-driven approaches for the treatment of pain in IBS-D

Postinfective bowel dysfunction following Campylobacter enteritis is characterised by reduced microbiota diversity and impaired microbiota recovery

Objectives Persistent bowel dysfunction following gastroenteritis (postinfectious (PI)-BD) is well recognised, but the associated changes in microbiota remain unclear. Our aim was to define these changes after gastroenteritis caused by a single organism, Campylobacter jejuni, examining the dynamic changes in the microbiota and the impact of antibiotics. Design A single-centre cohort study of 155 patients infected with Campylobacter jejuni. Features of the initial illness as well as current bowel symptoms and the intestinal microbiota composition were recorded soon after infection (visit 1, 80 days later (visits 2 and 3). Microbiota were assessed using 16S rRNA sequencing. Results PI-BD was found in 22 of the 99 patients who completed the trial. The cases reported significantly looser stools, with more somatic and gastrointestinal symptoms. Microbiota were assessed in 22 cases who had significantly lower diversity and altered microbiota composition compared with the 44 age-matched and sex-matched controls. Moreover 60 days after infection, cases showed a significantly lower abundance of 23 taxa including phylum Firmicutes, particularly in the order Clostridiales and the family Ruminoccocaceae, increased Proteobacteria abundance and increased levels of Fusobacteria and Gammaproteobacteria. The microbiota changes were linked with diet; higher fibre consumption being associated with lower levels of Gammaproteobacteria. Conclusion The microbiota of PI-BD patients appeared more disturbed by the initial infection compared with the microbiota of those who recovered. The prebiotic effect of high fibre diets may inhibit some of the disturbances seen in PI-BD.Peer reviewe

Corticotrophin releasing factor increases ascending colon volume after a fructose test meal in healthy humans: a randomised control trial

Background: Poorly absorbed, fermentable carbohydrates can provoke irritable bowel syndrome (IBS) symptoms by escaping absorption in the small bowel and being rapidly fermented in the colon in some susceptible subjects. IBS patients are often anxious and stressed and stress accelerates small bowel transit which may exacerbate malabsorption. Objective: In this study we investigated the effect of intravenous injection of corticotrophin releasing factor (CRF) on fructose malabsorption and the resulting volume of water in the small bowel. Design: We performed a randomised, placebo controlled, cross-over study of CRF versus saline injection in 11 male and 10 female healthy subjects, examining the effect on the malabsorption of a 40 g fructose test meal and its transit through the gut which was assessed by serial Magnetic Resonance imaging (MRI) and breath hydrogen measurement. Orocaecal transit was assessed using the lactose-ureide C13 breath test and the adrenal response to CRF assessed by serial salivary cortisol measurements. Results: (Mean ± SD) CRF injection caused a significant rise in salivary cortisol which lasted 135 minutes. Small bowel water content (SBWC) rose from baseline, peaking at 45 minutes after fructose ingestion while breath hydrogen peaked later at 75 minutes. The area under the curve (AUC) for SBWC from -15 - 135 minutes was significantly lower after CRF versus saline (mean difference [95% CI] 7433 [275, 14591] mL.min, P = 0.04). Ascending colon volume rose after CRF, significantly more for male volunteers than female (P = 0.025). Conclusions: CRF constricts the small bowel and increases fructose malabsorption as shown by increased ascending colon volumes. This mechanism may help to explain the increased sensitivity of some stressed individuals to fructose malabsorption. This trial was registered at ClinicalTrials.gov as NCT0176328

Gastrointestinal peptides and small bowel hypomotility are possible causes for fasting and postprandial symptoms in active Crohn’s disease

BackgroundCrohn's disease (CD) patients suffer postprandial aversive symptoms, which can lead to anorexia and malnutrition. Changes in the regulation of gut hormones and gut dysmotility are believed to play a role.ObjectivesThis study aimed to investigate small-bowel motility and gut peptide responses to a standard test meal in CD by using MRI.MethodsWe studied 15 CD patients with active disease (age 36 ± 3 y; BMI 26 ± 1 kg/m 2) and 20 healthy volunteers (HVs; age 31 ± 3 years; BMI 24 ± 1 kg/m 2). They underwent baseline and postprandial MRI scans, symptom questionnaires, and blood sampling following a 400-g soup meal (204 kcal). Small-bowel motility, other MRI parameters, and glucagon-like peptide-1 (GLP-1), polypeptide YY (PYY), and cholecystokinin peptides were measured. Data are presented as means ± SEMs.ResultsHVs had significantly higher fasting motility indexes [106 ± 13 arbitrary units (a.u.)], compared with CD participants (70 ± 8 a.u.; P ≤ 0.05). Postprandial small-bowel water content showed a significant time by group interaction (P < 0.05), with CD participants showing higher levels from 210 min postprandially. Fasting concentrations of GLP-1 and PYY were significantly greater in CD participants, compared with HVs [GLP-1, CD 50 ± 8 µg/mL versus HV 13 ± 3 µg/mL (P ≤ 0.0001); PYY, CD 236 ± 16 pg/mL versus HV 118 ± 12 pg/mL (P ≤ 0.0001)]. The meal challenge induced a significant postprandial increase in aversive symptom scores (fullness, distention, bloating, abdominal pain, and sickness) in CD participants compared with HVs (P ≤ 0.05).ConclusionsThe decrease in fasting small-bowel motility noted in CD participants can be ascribed to the increased fasting gut peptides. A better understanding of the etiology of aversive symptoms in CD will facilitate identification of better therapeutic targets to improve nutritional status. This trial was registered at clinicaltrials.gov as NCT03052465

Effects of helicobacter pylori infection on iron metabolism genes in patients with iron deficiency anaemia

This is an accepted manuscript of an article published by BMJ in Gut on 08/06/2018, available online: http://dx.doi.org/10.1136/gutjnl-2018-BSGAbstracts.282 The accepted version of the publication may differ from the final published version.Published versio

Characterisation of faecal protease activity in irritable bowel syndrome with diarrhoea: origin and effect of gut transit

OBJECTIVES: Faecal serine proteases (FSPs) may play a role in irritable bowel syndrome with diarrhoea (IBS-D), but their origin is unclear. We aimed to structurally characterise them and define the impact of colonic cleansing and transit time. DESIGN: Faecal samples were obtained from 30 healthy volunteers (HV) and 79 patients with IBS-D participating in a trial of ondansetron versus placebo. Colonic transit was measured using radio-opaque markers. Samples were also obtained from 24 HV before and after colonic cleansing with the osmotic laxative MoviPrep. FSPs were purified from faecal extracts using benzamidine-Sepharose affinity chromatography. SDS-PAGE profiled components were identified using trypsinolysis and tandem mass spectrometry. Functional protease activity in faecal extracts was measured using a colorimetric assay based on the proteolysis of azo-casein. RESULTS: Protein analysis identified the most abundant FSPs as being of human origin and probably derived from pancreatic juice. Functional assays showed increased faecal protease (FP) and amylase in patients with IBS-D compared with HV. Those with higher amylase had significantly higher FP and greater anxiety. FP activity correlated negatively with whole gut transit in patients with IBS-D (Spearman r=−0.32, p=0.005) and HV (r=−0.55, p=0.014). Colon cleansing caused a significant rise in FP activity in HV from a baseline of median (IQR) 253 (140–426) to 1031 (435–2296), levels similar to those seen in patients with IBS-D. FSP activity correlated positively with days/week with urgency. CONCLUSIONS: The most abundant FSPs are of human origin. Rapid transit through the colon and/or decreased (possibly bacterial) proteolytic degradation increases their faecal concentration and could contribute to visceral hypersensitivity in patients with IBS-D. CLINICALTRIALS.GOV: NCT00745004

A mechanistic multi-centre, parallel group, randomised placebo controlled trial of Mesalazine for treatment of irritable bowel syndrome with diarrhoea (IBS-D)

Introduction: Immune activation has been reported in the mucosa of irritable bowel syndrome patients with diarrhoea (IBS-D) and some small studies have suggested that Mesalazine may reduce symptoms. We performed a double blind, randomised placebo controlled trial of 2g Mesalazine twice daily versus placebo for 3 months in Rome III criteria IBS-D patients. Primary outcome was daily average stool frequency during weeks 11-12; secondary outcomes were abdominal pain, stool consistency, urgency and satisfactory relief of IBS symptoms. Methods: Participants were randomised after a 2-week baseline stool diary. All participants completed a 12-week stool diary and at the end of each week recorded the presence of “satisfactory relief of IBS symptoms”. Results: 136 patients with IBS-D (82 F, 54 M) were randomised, 10 patients withdrew from each group. Analysis by intention to treat showed the daily average stool frequency during weeks 11 and 12 were mean (SD), 2.8 (1.2) in Mesalazine and 2.7 (1.9) in placebo group with no significant group difference (95% confidence interval) 0.1 (-0.33,0.53); p=0.66. Mesalazine did not improve abdominal pain, stool consistency nor percentage with satisfactory relief compared to placebo during the last 2 weeks follow up. Conclusion: This study does not support any clinically meaningful benefit or harm of Mesalazine compared with placebo in unselected IBS with diarrhoea. More precise subtyping based on underlying disease mechanisms is needed to allow more effective targeting of treatment in IBS. (ClinicalTrials.gov number NCT01316718

Study design for development of novel safety biomarkers of drug-induced liver injury by the translational safety biomarker pipeline (TransBioLine) consortium: a study protocol for a nested case–control study

A lack of biomarkers that detect drug-induced liver injury (DILI) accurately continues to hinder early- and late-stage drug development and remains a challenge in clinical practice. The Innovative Medicines Initiative’s TransBioLine consortium comprising academic and industry partners is developing a prospective repository of deeply phenotyped cases and controls with biological samples during liver injury progression to facilitate biomarker discovery, evaluation, validation and qualification.In a nested case–control design, patients who meet one of these criteria, alanine transaminase (ALT) ≥ 5 × the upper limit of normal (ULN), alkaline phosphatase ≥ 2 × ULN or ALT ≥ 3 ULN with total bilirubin > 2 × ULN, are enrolled. After completed clinical investigations, Roussel Uclaf Causality Assessment and expert panel review are used to adjudicate episodes as DILI or alternative liver diseases (acute non-DILI controls). Two blood samples are taken: at recruitment and follow-up. Sample size is as follows: 300 cases of DILI and 130 acute non-DILI controls. Additional cross-sectional cohorts (1 visit) are as follows: Healthy volunteers (n = 120), controls with chronic alcohol-related or non-alcoholic fatty liver disease (n = 100 each) and patients with psoriasis or rheumatoid arthritis (n = 100, 50 treated with methotrexate) are enrolled. Candidate biomarkers prioritised for evaluation include osteopontin, glutamate dehydrogenase, cytokeratin-18 (full length and caspase cleaved), macrophage-colony-stimulating factor 1 receptor and high mobility group protein B1 as well as bile acids, sphingolipids and microRNAs. The TransBioLine project is enabling biomarker discovery and validation that could improve detection, diagnostic accuracy and prognostication of DILI in premarketing clinical trials and for clinical healthcare application