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ObjectivesClinical studies revealed that early-life adverse events contribute to the development of IBS in adulthood. The aim of our study was to investigate the relationship between prenatal stress (PS), gut microbiota and visceral hypersensitivity with a focus on bacterial lipopeptides containing γ-aminobutyric acid (GABA).DesignWe developed a model of PS in mice and evaluated, in adult offspring, visceral hypersensitivity to colorectal distension (CRD), colon inflammation, barrier function and gut microbiota taxonomy. We quantified the production of lipopeptides containing GABA by mass spectrometry in a specific strain of bacteria decreased in PS, in PS mouse colons, and in faeces of patients with IBS and healthy volunteers (HVs). Finally, we assessed their effect on PS-induced visceral hypersensitivity.ResultsPrenatally stressed mice of both sexes presented visceral hypersensitivity, no overt colon inflammation or barrier dysfunction but a gut microbiota dysbiosis. The dysbiosis was distinguished by a decreased abundance of Ligilactobacillus murinus, in both sexes, inversely correlated with visceral hypersensitivity to CRD in mice. An isolate from this bacterial species produced several lipopeptides containing GABA including C14AsnGABA. Interestingly, intracolonic treatment with C14AsnGABA decreased the visceral sensitivity of PS mice to CRD. The concentration of C16LeuGABA, a lipopeptide which inhibited sensory neurons activation, was decreased in faeces of patients with IBS compared with HVs.ConclusionPS impacts the gut microbiota composition and metabolic function in adulthood. The reduced capacity of the gut microbiota to produce GABA lipopeptides could be one of the mechanisms linking PS and visceral hypersensitivity in adulthood.

The intestinal tract faces numerous challenges that require several layers of defence. The tight epithelium forms a physical barrier that is further protected by a mucus layer, which provides various site-specific protective functions. Mucus is produced by goblet cells, and as a result of single-cell RNA sequencing identifying novel goblet cell subpopulations, our understanding of their various contributions to intestinal homeostasis has improved. Goblet cells not only produce mucus but also are intimately linked to the immune system. Mucus and goblet cell development is tightly regulated during early life and synchronized with microbial colonization. Dysregulation of the developing mucus systems and goblet cells has been associated with infectious and inflammatory conditions and predisposition to chronic disease later in life. Dysfunctional mucus and altered goblet cell profiles are associated with inflammatory conditions in which some mucus system impairments precede inflammation, indicating a role in pathogenesis. In this Review, we present an overview of the current understanding of the role of goblet cells and the mucus layer in maintaining intestinal health during steady-state and how alterations to these systems contribute to inflammatory and infectious disease.Mucus, produced by goblet cells, provides the intestinal tract with an additional layer of protection. This Review discusses the role of mucus and goblet cells in intestinal health and disease, and dissects the underlying regulatory mechanisms.

Fermentation of dietary fiber in the colon results in the production of short chain fatty acids (mainly propionate, butyrate and acetate). Butyrate modulates a wide range of processes, but its mechanism of action is mostly unknown. This study aimed to determine the effects of butyrate on the transcriptional regulation of human colonic mucosa in vivo. Five hundred genes were found to be differentially expressed after a two week daily butyrate administration with enemas. Pathway analysis showed that the butyrate intervention mainly resulted in an increased transcriptional regulation of the pathways representing fatty acid oxidation, electron transport chain and oxidative stress. In addition, several genes associated with epithelial integrity and apoptosis, were found to be differentially expressed after the butyrate intervention. Colonic administration of butyrate in concentrations that can be achieved by consumption of a high-fiber diet enhances the maintenance of colonic homeostasis in healthy subjects, by regulating fatty acid metabolism, electron transport and oxidative stress pathways on the transcriptional level and provide for the first time, detailed molecular insight in the transcriptional response of gut mucosa to butyrate.

ObjectiveThe colonic inner mucus layer protects us from pathogens and commensal-induced inflammation, and has been shown to be defective in active UC. The aim of this study was to determine the underlying compositional alterations, their molecular background and potential contribution to UC pathogenesis.DesignIn this single-centre case–control study, sigmoid colon biopsies were obtained from patients with UC with ongoing inflammation (n=36) or in remission (n=28), and from 47 patients without colonic disease. Mucus samples were collected from biopsies ex vivo, and their protein composition analysed by nanoliquid chromatography-tandem mass spectrometry. Mucus penetrability and goblet cell responses to microbial stimulus were assessed in a subset of patients.ResultsThe core mucus proteome was found to consist of a small set of 29 secreted/transmembrane proteins. In active UC, major structural mucus components including the mucin MUC2 (p<0.0001) were reduced, also in non-inflamed segments. Active UC was associated with decreased numbers of sentinel goblet cells and attenuation of the goblet cell secretory response to microbial challenge. Abnormal penetrability of the inner mucus layer was observed in a subset of patients with UC (12/40; 30%). Proteomic alterations in penetrable mucus samples included a reduction of the SLC26A3 apical membrane anion exchanger, which supplies bicarbonate required for colonic mucin barrier formation.ConclusionCore mucus structural components were reduced in active UC. These alterations were associated with attenuation of the goblet cell secretory response to microbial challenge, but occurred independent of local inflammation. Thus, mucus abnormalities are likely to contribute to UC pathogenesis.

Objectives:Patients with irritable bowel syndrome (IBS) are more likely to be both absent from and impaired at work compared to non-IBS patients. We investigated the impact of IBS on work productivity and activity impairment and the relationship to disease specific and general health measures.Method:In total, 525 patients with IBS completed questionnaires assessing work productivity and activity impairment, IBS symptom severity, IBS-related quality of life and GI-specific anxiety. In addition, 155 of the patients completed questionnaires assessing severity of somatic symptoms, depression, anxiety and fatigue. Uni- and bivariate analyses were performed, as well as linear regression to determine factors independently associated with the work productivity and activity impairment measures.Results:Of employed patients, 24.3% reported absenteeism and 86.8% reported presenteeism because of their IBS. With increasing severity of IBS symptoms and GI-specific anxiety, higher degrees of work impairment were seen. Work productivity impairment in IBS was also associated with low quality of life. GI-specific anxiety was independently associated with absenteeism (R2 = 0.23; p < 0.05), IBS-symptom severity and general fatigue with presenteeism (R2 = 0.40; p < 0.05), IBS-symptom severity, general fatigue and GI-specific anxiety with overall work loss (R2 = 0.50; p < 0.05), and IBS symptom severity and somatic symptoms with activity impairment (R2 = 0.38; p < 0.05).Conclusion:Work impairment is a substantial problem in patients with IBS. A combination of IBS and somatic symptom severity, fatigue and psychological factors influence patients’ ability to be present, active and productive at work. Based on this, a multidimensional treatment approach for patients with IBS seems logical.

ObjectiveAmpullary neoplastic lesions can be resected by endoscopic papillectomy (EP) or transduodenal surgical ampullectomy (TSA) while pancreaticoduodenectomy is reserved for more advanced lesions. We present the largest retrospective comparative study analysing EP and TSA.DesignOf all patients in the database, lesions with prior interventions, benign histology advanced malignancy (T2 and more), patients with hereditary syndromes and those undergoing pancreatoduodenectomy were excluded. All remaining cases as well as a subgroup of them, after propensity-score matching (nearest-neighbour-method) based on age, gender, anthropometrics, comorbidities, size and histological subtype, were analysed. The median follow-up was 21 months (IQR 10–47) after the primary intervention. Primary outcomes were rates of complete resection (R0) and complications. Groups were compared by Fisher’s exact or χ2 test, Mann-Whitney-U-test and log-rank test for survival.ResultsOf 1673 patients in the database, 1422 underwent EP and 251 TSA. Of them, 23.2% were excluded for missing or inconclusive data and 19.8% of patients for prior interventions or hereditary syndromes. Final histology showed in 24.2% of EP and 14.8% of TSA patients a histology other than adenoma or adenocarcinoma while advanced cancers were recorded in 10.9% of EP and 36.6% of TSA patients. Finally, 569 EP and 63 TSA were included in the overall analysis, with a higher rate of more advanced cases and higher R0 resection rates in the TSA groups (90.5% vs 73.1%; p<0.01), with additional ablation in the EP group in 14.4%. Severe adverse event rates were 3.2% (TSA) vs 1.9% (EP). Recurrence after histological R0 resection was 16% (EP) vs 3.2% (TSA; p=0.01), and additional therapy for R1 resection was applied in 67% of the 159 cases. Propensity-score-based matching identified 62 pairs of EP/TSA patients with comparable baseline patient and lesion characteristics. The initial R0-rate was 72.6% (EP) compared with 90.3% (TSA, p=0.02) with recurrences found in 8% (EP) vs 3.2% (TSA; p=0.07); reinterventions were more frequent in the EP group. Overall survival was comparable.ConclusionsThe rate of patients with poor indications due to non-neoplastic disease or advanced cancer is still high for both EP and TSA; multiple retreatments were necessary for EP. Although EP can be considered an appropriate primary therapy for certain ampullary adenomas, case selection for both therapies (especially with regard to the best step-up approach) should be studied further.

Faecal microbiota transplantation (FMT) is an important therapeutic option for Clostridium difficile infection. Promising findings suggest that FMT may play a role also in the management of other disorders associated with the alteration of gut microbiota. Although the health community is assessing FMT with renewed interest and patients are becoming more aware, there are technical and logistical issues in establishing such a non-standardised treatment into the clinical practice with safety and proper governance. In view of this, an evidence-based recommendation is needed to drive the practical implementation of FMT. In this European Consensus Conference, 28 experts from 10 countries collaborated, in separate working groups and through an evidence-based process, to provide statements on the following key issues: FMT indications; donor selection; preparation of faecal material; clinical management and faecal delivery and basic requirements for implementing an FMT centre. Statements developed by each working group were evaluated and voted by all members, first through an electronic Delphi process, and then in a plenary consensus conference. The recommendations were released according to best available evidence, in order to act as guidance for physicians who plan to implement FMT, aiming at supporting the broad availability of the procedure, discussing other issues relevant to FMT and promoting future clinical research in the area of gut microbiota manipulation. This consensus report strongly recommends the implementation of FMT centres for the treatment of C. difficile infection as well as traces the guidelines of technicality, regulatory, administrative and laboratory requirements.

Objectives:The population prevalence of Rome IV-diagnosed functional gastrointestinal disorders (FGIDs) and their cumulative effect on health impairment is unknown.Methods:An internet-based cross-sectional health survey was completed by 5,931 of 6,300 general population adults from three English-speaking countries (2100 each from USA, Canada, and UK). Quota-based sampling was used to generate demographically balanced and population representative samples with regards to age, sex, and education level. The survey enquired for demographics, medication, surgical history, somatization, quality of life (QOL), doctor-diagnosed organic GI disease, and criteria for the Rome IV FGIDs. Comparisons were made between those with Rome IV-diagnosed FGIDs against non-GI (healthy) and organic GI disease controls.Results:The number of subjects having symptoms compatible with a FGID was 2,083 (35%) compared with 3,421 (57.7%) non-GI and 427 (7.2%) organic GI disease controls. The most frequently met diagnostic criteria for FGIDs was bowel disorders (n=1,665, 28.1%), followed by gastroduodenal (n=627, 10.6%), anorectal (n=440, 7.4%), esophageal (n=414, 7%), and gallbladder disorders (n=10, 0.2%). On average, the 2,083 individuals who met FGID criteria qualified for 1.5 FGID diagnoses, and 742 of them (36%) qualified for FGID diagnoses in more than one anatomic region. The presence of FGIDs in multiple regions was associated with increasing somatization, worse mental/physical QOL, more medical therapies, and a higher prevalence of abdominal surgeries; all P<0.001. Notably, individuals with FGIDs in multiple regions had greater somatization and worse QOL than organic GI disease controls.Conclusions:Roughly a third of the general adult population fulfils diagnostic criteria for a Rome IV FGID. In a third of this subset multiple GI regions are involved and this overlap is associated with increased health impairment.

Background and aimsGut transit time is a key modulator of host–microbiome interactions, yet this is often overlooked, partly because reliable methods are typically expensive or burdensome. The aim of this single-arm, single-blinded intervention study is to assess (1) the relationship between gut transit time and the human gut microbiome, and (2) the utility of the ‘blue dye’ method as an inexpensive and scalable technique to measure transit time.MethodsWe assessed interactions between the taxonomic and functional potential profiles of the gut microbiome (profiled via shotgun metagenomic sequencing), gut transit time (measured via the blue dye method), cardiometabolic health and diet in 863 healthy individuals from the PREDICT 1 study.ResultsWe found that gut microbiome taxonomic composition can accurately discriminate between gut transit time classes (0.82 area under the receiver operating characteristic curve) and longer gut transit time is linked with specific microbial species such as Akkermansia muciniphila, Bacteroides spp and Alistipes spp (false discovery rate-adjusted p values <0.01). The blue dye measure of gut transit time had the strongest association with the gut microbiome over typical transit time proxies such as stool consistency and frequency.ConclusionsGut transit time, measured via the blue dye method, is a more informative marker of gut microbiome function than traditional measures of stool consistency and frequency. The blue dye method can be applied in large-scale epidemiological studies to advance diet-microbiome-health research. Clinical trial registry website https://clinicaltrials.gov/ct2/show/NCT03479866 and trial number NCT03479866.

ObjectiveGut microbiota could influence gut, as well as hepatic and biliary immune responses. We therefore thoroughly characterised the gut microbiota in primary sclerosing cholangitis (PSC) compared with healthy controls (HC) and patients with ulcerative colitis without liver disease.DesignWe prospectively collected 543 stool samples. After a stringent exclusion process, bacterial DNA was submitted for 16S rRNA gene sequencing. PSC and HC were randomised to an exploration panel or a validation panel, and only significant results (p<0.05, QFDR<0.20) in both panels were reported, followed by a combined comparison of all samples against UC.ResultsPatients with PSC (N=85) had markedly reduced bacterial diversity compared with HC (N=263, p<0.0001), and a different global microbial composition compared with both HC (p<0.001) and UC (N=36, p<0.01). The microbiota of patients with PSC with and without IBD was similar. Twelve genera separated PSC and HC, out of which 11 were reduced in PSC. However, the Veillonella genus showed a marked increase in PSC compared with both HC (p<0.0001) and UC (p<0.02). Using receiver operating characteristic analysis, Veillonella abundance yielded an area under the curve (AUC) of 0.64 to discriminate PSC from HC, while a combination of PSC-associated genera yielded an AUC of 0.78.ConclusionsPatients with PSC exhibited a gut microbial signature distinct from both HC and UC without liver disease, but similar in PSC with and without IBD. The Veillonella genus, which is also associated with other chronic inflammatory and fibrotic conditions, was enriched in PSC.