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There is comorbidity between anxiety disorders and gastrointestinal disorders, with both linked to adverse early life events. The microbiome gut-brain-axis, a bidirectional communication system, is plastic throughout the neonatal period and is a possible mediator of this relationship. Here, we used a well-established neonatal rodent immune activation model to investigate the long-term effect of neonatal lipopolysaccharide (LPS) exposure on adult behaviour and the relationship to microbiome composition. Wistar rats were injected with LPS (0.05 mg/kg) or saline (equivolume) on postnatal days 3 and 5. In adulthood, behavioural tests were performed to assess anxiety-like behaviour, and microbiota sequencing was performed on stool samples. There were distinctly different behavioural phenotypes for LPS-exposed males and females. LPS-exposed males displayed typical anxiety-like behaviours with significantly decreased social interaction (F (1,22)  = 7.576, p = 0.009) and increased defecation relative to saline controls (F (1,23)  = 8.623, p = 0.005). LPS-exposed females displayed a different behavioural phenotype with significantly increased social interaction (F (1,22)  = 6.094, p = 0.018), and exploration (F (1,24)  = 6.359, p = 0.015), compared to saline controls. With respect to microbiota profiling data, Bacteroidota was significantly increased for LPS-exposed females (F (1,14)  = 4.931p = 0.035) and Proteobacteria was decreased for LPS-exposed rats of both sexes versus controls (F (1,30)  = 4.923p = 0.035). Furthermore, alterations in predicted functional pathways for neurotransmitters in faeces were observed with a decrease in the relative abundance of D-glutamine and D-glutamate metabolism in LPS exposed females compared to control females (p < 0.05). This suggests that neonatal immune activation alters both later life behaviour and adult gut microbiota in sex-specific ways. These findings highlight the importance of sex in determining the impact of neonatal immune activation on social behaviour and the gut microbiota., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Background: There is limited empirical evidence of the magnitude of the discrepancy between prospectively recorded gastrointestinal symptom burden and that reported in recall questionnaires. Further, potential sources of the discrepancy are largely unknown. This study sought to quantify the discrepancy and to evaluate the potential role of mood disorder and emotion regulation in the discrepancy., Methods: One hundred and forty nine subjects (mean age 20 years, 75% female) who met Rome IV criteria for irritable bowel syndrome and/or functional dyspepsia completed a 7-day prospective recording of the symptoms on a smartphone implemented ecological momentary assessment app, and then on day 8 were asked to recall their symptoms for the preceding 7 days., Key Results: Gastrointestinal symptom burden assessed by recall was exaggerated relative to that recorded prospectively. The discrepancy was moderate for overall score (Cohen d = 0.52), abdominal pain (d = 0.61) and indigestion (d = 0.49). The discrepancy was generally larger among subjects who reported a physician diagnosis of a gastrointestinal condition with d = 0.87 for overall score and d = 0.89 for abdominal pain. A number of correlations between the discrepancy and psychological traits were identified, including neuroticism with diarrhea discrepancy (r = 0.23, p = 0.004) and visceral-specific anxiety with abdominal pain discrepancy (r = -0.18, p = 0.03). There was no evidence of recency or Hawthorne (observer) effects., Conclusions and Inferences: Reports of gastrointestinal symptoms obtained via recall are likely to be exaggerated relative to the actual patient experience, particularly among healthcare seekers. While psychological traits are likely to play some role, much more needs to be understood about the discrepancy., (© 2021 John Wiley & Sons Ltd.)

Human colonic spirochetosis (CS) is usually due toBrachyspira pilosicolior Brachyspira aalborgiinfection. While traditionally considered to be commensal bacteria, there are scattered case reports and case series of gastrointestinal (GI) symptoms in CS and reports of colonic polyps with adherent spirochetes. We performed a systematic review and meta-analysis investigating the association between CS and GI symptoms and conditions including the irritable bowel syndrome (IBS) and colonic polyps. Following PRISMA 2020 guidelines, a systematic search of Medline, CINAHL, EMBASE, and Web of Science was performed using specific keywords for CS and GI disease. Pooled odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using a random-effects model. Of 75 studies identified in the search, 8 case-control studies met the inclusion criteria for meta-analysis and 67 case series studies met the inclusion criteria for pooled prevalence analysis. CS was significantly associated with diarrhea (n = 141/127, cases/controls, OR: 4.19, 95% CI: 1.72-10.21, P = 0.002) and abdominal pain (n = 64/65, OR: 3.66, 95% CI: 1.43-9.35, P = 0.007). CS cases were significantly more likely to have Rome III-diagnosed IBS (n = 79/48, OR: 3.84, 95% CI: 1.44-10.20, P = 0.007), but not colonic polyps (n = 127/843, OR: 8.78, 95% CI: 0.75-103.36, P = 0.084). In conclusion, we found evidence of associations between CS and both diarrhea and IBS, but not colonic polyps. CS is likely underestimated due to suboptimal diagnostic methods and may be an overlooked risk factor for a subset of IBS patients with diarrhea., (© 2022 The Authors. Journal of Gastroenterology and Hepatology published by Journal of Gastroenterology and Hepatology Foundation and John Wiley & Sons Australia, Ltd.)

Background and Aims: Antimicrobial therapy improves symptoms in patients with irritable bowel syndrome (IBS), but the efficacy in functional dyspepsia (FD) is largely unknown. While FD and IBS frequently overlap, it is unknown if concomitant IBS in FD alters the response to antimicrobial therapy in FD. Thus, we aimed to assess and compare the effect of antimicrobial therapy on visceral sensory function and symptom improvement in FD patients with and without IBS., Methods: Adult patients with FD with or without IBS received rifaximin 550 mg BD for 10 days, followed by a 6-week follow-up period. The total gastrointestinal symptom score as measured by the SAGIS (Structured Assessment of Gastrointestinal Symptoms) questionnaire and subscores (dyspepsia, diarrhea, and constipation), symptom response to a standardized nutrient challenge and normalization of the glucose breath tests were measured., Results: Twenty-one consecutive adult patients with FD and 14/21 with concomitant IBS were recruited. Treatment with rifaximin resulted in a significant (p = 0.017) improvement in the total SAGIS score from 34.7 (± 15.4) at baseline to 26.0 (± 16.8) at 2 weeks and 25.6 (± 17.8) at 6 weeks post-treatment. Similarly, compared to baseline there was a statistically significant improvement in SAGIS subscores for dyspepsia and diarrhea (all p < 0.05) and effects persisted for 6 weeks post-treatment. Similarly, the symptom score (and subscores) following a standardized nutrient challenge improved significantly (p < 0.001) 2 weeks post-treatment. The presence of concomitant IBS did not significantly influence the improvement of symptoms after antibiotic therapy (all p > 0.5)., Conclusions: In FD patients, the response to antimicrobial therapy with rifaximin is not influenced by concomitant IBS symptoms., (© 2021. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Diet plays a key role in the manifestation and severity of gastrointestinal symptoms, with increasing research interest on the role of diet in small bowel disorders. There are predominantly 3 small bowel conditions that have potential dietary interventions. Self-reported nonceliac gluten/wheat sensitivity is prevalent. Although gluten is believed to be a potential trigger for symptoms, other components of wheat may also be triggers, including fructans, alpha-amylase trypsin inhibitors, and wheat germ agglutinins. The diagnosis can be challenging, given the lack of validated biomarkers. A gluten-free diet that excludes the abovementioned triggers is the cornerstone of treatment; however, unlike celiac disease, there is uncertainty about the level of adherence or whether the gluten-free diet is a lifelong intervention. Several primary gastrointestinal disorders are associated with an increase in inflammatory cells including eosinophils. Diet seems to be an important driver of disease pathogenesis in eosinophilic gastroenteritis, with elimination and elemental diets showing promise in management, with further robust trials required. Small intestinal bacterial overgrowth is an example of microbial dysbiosis, with renewed interest in diet being postulated to cause an adaptive change of the microbes colonizing the small intestine. However, the diagnosis of small intestinal bacterial overgrowth is limited by a lack of sensitive and specific tests, with significant knowledge gaps in relation to therapeutic measures to manage and cure small intestinal bacterial overgrowth. Currently, antimicrobials are the established management option. There have been significant clinical advances in dietary interventions related to the small bowel, but this area is currently a novel and advancing field for both patients and clinicians., (Copyright © 2022 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of The American College of Gastroenterology.)

Functional dyspepsia (FD) is a highly prevalent disorder of gut-brain interaction (DGBI), previously known as a functional gastrointestinal disorder. Characterized by early satiety, postprandial fullness, and/or epigastric pain or burning, diagnosis depends on positive symptomatology and exclusion of obvious structural diseases. A subtle inflammatory phenotype has been identified in FD patients, involving an increase in duodenal mucosal eosinophils, and imbalances in the duodenal gut microbiota. A dysregulated epithelial barrier has also been well described in FD and is thought to be a contributing factor to the low-grade duodenal inflammation observed, however the mechanisms underpinning this are poorly understood. One possible explanation is that alterations in the microbiota and increased immune cells can result in the activation of cellular stress response pathways to perpetuate epithelial barrier dysregulation. One such cellular response pathway involves the stabilization of hypoxia-inducible factors (HIF). HIF, a transcriptional protein involved in the cellular recognition and adaptation to hypoxia, has been identified as a critical component of various pathologies, from cancer to inflammatory bowel disease (IBD). While the contribution of HIF to subtle inflammation, such as that seen in FD, is unknown, HIF has been shown to have roles in regulating the inflammatory response, particularly the recruitment of eosinophils, as well as maintaining epithelial barrier structure and function. As such, we aim to review our present understanding of the involvement of eosinophils, barrier dysfunction, and the changes to the gut microbiota including the potential pathways and mechanisms of HIF in FD. A combination of PubMed searches using the Mesh terms functional dyspepsia, functional gastrointestinal disorders, disorders of gut-brain interaction, duodenal eosinophilia, barrier dysfunction, gut microbiota, gut dysbiosis, low-grade duodenal inflammation, hypoxia-inducible factors (or HIF), and/or intestinal inflammation were undertaken in the writing of this narrative review to ensure relevant literature was included. Given the findings from various sources of literature, we propose a novel hypothesis involving a potential role for HIF in the pathophysiological mechanisms underlying FD., Competing Interests: SH declares no conflicts of interest. GB declares no conflicts of interest. EH declares no conflicts of interest. SK declares grant/research support from Cancer Institute NSW (Career Development Fellowship), National Health and Medical Research Council (Center of Research Excellence, Project and Ideas Grant), Viscera Labs, Gossamer Bio, Anatara Lifesciences, Microba (Funded research and consultancy). NT reports, non-financial support from HVN National Science Challenge NZ, personal fees from Aviro Health (Digestive health) (2019), Anatara Life Sciences, Brisbane (2019), Allakos (gastric eosinophilic disease) (2021), Bayer (IBS) (2020), Danone (Probiotic) (2018), Planet Innovation (Gas capsule IBS) (2020), Takeda, Japan (gastroparesis) (2019), twoXAR (2019) (IBS drugs), Viscera Labs, (USA 2021) (IBS-diarrhea), Dr Falk Pharma (2020) (EoE), Censa, Wellesley MA USA (2019) (Diabetic gastroparesis), Cadila PharmIncaceuticals (CME) (2019), Progenity Inc. San Diego, (USA 2019) (Intestinal capsule), Sanofi-aventis, Sydney (2019) (Probiotic), Glutagen (2020) (Celiac disease), ARENA Pharmaceuticals (2019) (Abdominal pain), IsoThrive (2021) (esophageal microbiome), BluMaiden (2021), Rose Pharma (2021), Intrinsic Medicine (2021), Comvita Mānuka Honey (2021) outside the submitted work; In addition, NT has a patent Nepean Dyspepsia Index (NDI) 1998, Biomarkers of IBS licensed, a patent Licensing Questionnaires Talley Bowel Disease Questionnaire licensed to Mayo/Talley, a patent Nestec European Patent licensed, and a patent Singapore Provisional Patent “Microbiota Modulation Of BDNF Tissue Repair Pathway” issued, “Diagnostic marker for functional gastrointestinal disorders” Australian Provisional Patent Application 2021901692. Committees: OzSage, Australian Medical Council (AMC) [Council Member]; Australian Telehealth Integration Programme; MBS Review Taskforce; NHMRC Principal Committee (Research Committee) Asia Pacific Association of Medical Journal Editors. Boards: GESA Board Member, Sax Institute, Committees of the Presidents of Medical Colleges. Community group: Advisory Board, IFFGD (International Foundation for Functional GI Disorders), AusEE. Miscellaneous: Avant Foundation (judging of research grants). Editorial: Medical Journal of Australia (Editor in Chief), Up to Date (Section Editor), Precision and Future Medicine, Sungkyunkwan University School of Medicine, South Korea, Med (Journal of Cell Press). NT is supported by funding from the National Health and Medical Research Council (NHMRC) to the Center for Research Excellence in Digestive Health and he holds an NHMRC Investigator grant., (Copyright © 2022 Hari, Burns, Hoedt, Keely and Talley.)

The development and application of next generation sequencing technologies for clinical gastroenterology research has provided evidence that microbial dysbiosis is of relevance for the pathogenesis of gastrointestinal and extra-intestinal diseases. Microbial dysbiosis is characterized as alterations of diversity, function, and density of the intestinal microbes. Emerging evidence suggests that alterations of the gastrointestinal microbiome are important for the pathophysiology of a variety of functional gastrointestinal conditions, e.g., irritable bowel syndrome (IBS) and functional dyspepsia (FD), also known as disorders of brain-gut axis interaction. Clinicians have for many years recognized that small intestinal bacterial overgrowth (SIBO) is typified by a microbial dysbiosis that is underpinned by abnormal bacterial loads in these sites. SIBO presents with symptoms which overlap with symptoms of FD and IBS, point toward the possibility that SIBO is either the cause or the consequence of functional gastrointestinal disorders (FGIDs). More recently, new terms including "intestinal methanogen overgrowth" and "small intestinal fungal overgrowth" have been introduced to emphasize the contribution of methane production by archea and fungi in small intestinal dysbiosis. There is emerging data that targeted antimicrobial treatment of SIBO in patients with FD who simultaneously may or may not have IBS, results in symptom improvement and normalization of positive breath tests. However, the association between SIBO and FGIDs remains controversial, since widely accepted diagnostic tests for SIBO are lacking. Culture of jejunal fluid aspirate has been proposed as the "traditional gold standard" for establishing the diagnosis of SIBO. Utilizing jejunal fluid culture, the results can potentially be affected by cross contamination from oropharyngeal and luminal microbes, and there is controversy regarding the best cut off values for SIBO diagnosis. Thus, it is rarely used in routine clinical settings. These limitations have led to the development of breath tests, which when compared with the "traditional gold standard," have sub-optimal sensitivity and specificity for SIBO diagnosis. With newer diagnostic approaches-based upon applications of the molecular techniques there is an opportunity to characterize the duodenal and colonic mucosa associated microbiome and associated gut microbiota dysbiosis in patients with various gastrointestinal and extraintestinal diseases. Furthermore, the role of confounders like psychological co-morbidities, medications, dietary practices, and environmental factors on the gastrointestinal microbiome in health and disease also needs to be explored., Competing Interests: NT reports personal fees from Allakos, Aviro Health, Antara Life Sciences, Arlyx, Bayer, Danone, Planet Innovation, Takeda, Viscera Labs, twoXAR, Viscera Labs, Dr. Falk Pharma, Censa, Cadila Pharmaceuticals, Progenity Inc., Sanofi-aventis, Glutagen, ARENA Pharmaceuticals, IsoThrive, BluMaiden, HVN National Science Challenge, non-financial support from HVN National Science Challenge NZ, outside the submitted work. In addition, NT has a patent Biomarkers of IBS licensed (#12735358.9-1405/2710383) and (#12735358.9-1405/2710384), a patent Licensing Questionnaires Talley Bowel Disease Questionnaire licensed to Mayo/NT, a patent Nestec European Patent licensed, and a patent Singapore Provisional Patent NTU Ref: TD/129/17 “Microbiota Modulation of BDNF Tissue Repair Pathway” issued and copyright Nepean Dyspepsia Index (NDI) 1998 and Editorial: Medical Journal of Australia (Editor in Chief), Up to Date (Section Editor), Precision and Future Medicine, Sungkyunkwan University School of Medicine, South Korea, Med (Journal of Cell Press). NT participates Committees: Australian Medical Council (AMC) Council Member (2016–2019), MBS Review Taskforce (2016–2020), NHMRC Principal Committee, Research Committee (2016–2021), Asia Pacific Association of Medical Journal Editors (APAME) (current), GESA Board Member (2017–2019). NT Misc: Avant Foundation (judging of research grants) (2019). NT community and patient advocacy groups: Advisory Board, IFFGD (International Foundation for Functional GI Disorders). NT holds an NHMRC Investigator grant. GH report to be on the advisory boards Australian Biotherapeutics, Glutagen, Bayer and received research support from Bayer, Abbott, Pfizer, Janssen, Takeda, Allergan. He serves on the Boards of the West Moreton Hospital and Health Service, Queensland, UQ Healthcare, Brisbane, and the Gastro-Liga, Germany. He has a patent for the Brisbane aseptic biopsy device and serves as Editor of the Gastro-Liga Newsletter. The remaining author declares that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Shah, Talley and Holtmann.)

Background: Irritable bowel syndrome (IBS) is considered a disorder of gut-brain interaction (DGBI), presenting as chronic abdominal pain and altered defaecation. Symptoms are often food related. Much work in the field has focused on identifying physiological, immune and microbial abnormalities in the colon of patients; however, evidence of small intestinal immune activation and microbial imbalance has been reported in small studies. The significance of such findings has been largely underappreciated despite a growing body of work implicating small intestinal homeostatic imbalance in the pathogenesis of DGBIs., Main Text: Small intestinal mechanosensation is a characteristic feature of IBS. Furthermore, altered small intestinal barrier functions have been demonstrated in IBS patients with the diarrhoea-predominant subtype. Small intestinal bacterial overgrowth and increased populations of small intestinal mast cells are frequently associated with IBS, implicating microbial imbalance and low-grade inflammation in the pathogenesis of IBS. Furthermore, reports of localised food hypersensitivity responses in IBS patients implicate the small intestine as the site of immune-microbial-food interactions., Conclusions: Given the association of IBS symptoms with food intake in a large proportion of patients and the emerging evidence of immune activation in these patients, the current literature suggests the pathogenesis of IBS is not limited to the colon but rather may involve dysfunction of the entire intestinal tract. It remains unclear if regional variation in IBS pathology explains the various symptom phenotypes and further work should consider the intestinal tract as a whole to answer this question., (© 2022. The Author(s).)

Circadian rhythms are cyclic patterns of physiological, behavioural and molecular events that occur over a 24-h period. They are controlled by the suprachiasmatic nucleus (SCN), the brain's master pacemaker which governs peripheral clocks and melatonin release. While circadian systems are endogenous, there are external factors that synchronise the SCN to the ambient environment including light/dark cycles, fasting/fed state, temperature and physical activity. Circadian rhythms also provide internal temporal organisation which ensures that any internal changes that take place are centrally coordinated. Melatonin synchronises peripheral clocks to the external time and circadian rhythms are regulated by gene expression to control physiological function. Synchronisation of the circadian system with the external environment is vital for the health and survival of an organism and as circadian rhythms play a pivotal role in regulating GI physiology, disruption may lead to gastrointestinal (GI) dysfunction. Disorders of gut-brain interactions (DGBIs), also known as functional gastrointestinal disorders (FGIDs), are a group of diseases where patients experience reoccurring gastrointestinal symptoms which cannot be explained by obvious structural abnormalities and include functional dyspepsia (FD) and irritable bowel syndrome (IBS). Food timing impacts on the production of melatonin and given the correlation between food intake and symptom onset reported by patients with DGBIs, chronodisruption may be a feature of these conditions. Recent advances in immunology implicate circadian rhythms in the regulation of immune responses, and DGBI patients report fatigue and disordered sleep, suggesting circadian disruption. Further, melatonin treatment has been demonstrated to improve symptom burden in IBS patients, however, the mechanisms underlying this efficacy are unclear. Given the influence of circadian rhythms on gastrointestinal physiology and the immune system, modulation of these rhythms may be a potential therapeutic option for reducing symptom burden in these patients., Competing Interests: NT non-financial support from HVN National Science Challenge NZ, personal fees from Aviro Health (Digestive health) (2019), Anatara Lifesciences, Brisbane (2019), Allakos (gastric eosinophilic disease) (2021), Bayer (2020), Danone (Probiotic) (2018), Planet Innovation (Gas capsule IBS) (2020), Takeda, Japan (gastroparesis) (2019), twoXAR (2019) (IBS drugs), Viscera Labs, (United States 2021) (IBS-diarrhoea), Dr. Falk Pharma (2020) (EoE), Censa, Wellesley, MA, United States (2019) (Diabetic gastroparesis), Cadila Pharmaceuticals (CME) (2019), Progenity Inc., San Diego, (United States 2019) (Intestinal capsule), Sanofi-Aventis, Sydney (2019) (Probiotic), Glutagen (2020) (Celiac disease), ARENA Pharmaceuticals (2019) (Abdominal pain), IsoThrive (2021) (oesophageal microbiome), BluMaiden (2021), Rose Pharma (2021), Intrinsic Medicine (2021) outside the submitted work; In addition, NT has a patent Nepean Dyspepsia Index (NDI) 1998, Biomarkers of IBS licensed, a patent Licensing Questionnaires Talley Bowel Disease Questionnaire licensed to Mayo/Talley, a patent Nestec European Patent licensed, and a patent Singapore Provisional Patent “Microbiota Modulation Of BDNF Tissue Repair Pathway” issued. Committees: Australian Medical Council (AMC) Council Member; Australian Telehealth Integration Program; MBS Review Taskforce; NHMRC Principal Committee (Research Committee) Asia Pacific Association of Medical Journal Editors. Boards: GESA Board Member, Sax Institute, Committees of the Presidents of Medical Colleges. Community group: Advisory Board, IFFGD (International Foundation for Functional GI Disorders). Miscellaneous: Avant Foundation (judging of research grants). Editorial: Medical Journal of Australia (Editor in Chief), Up to Date (Section Editor), Precision and Future Medicine, Sungkyunkwan University School of Medicine, South Korea, Med (Journal of Cell Press). NT is supported by funding from the National Health and Medical Research Council (NHMRC) to the Centre for Research Excellence in Digestive Health and he holds an NHMRC Investigator grant. SK Grant/Research Support: National Health and Medical Research Council (Ideas Grant and Centre for Research Excellence) Viscera Labs (Research contract), Microba Life Science (Research contract). Consultant/Advisory Boards: Gossamer Bio (Scientific Advisory Board), Anatara Lifesciences (Scientific Advisory Board), Microba Life Science (Consultancy). The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Fowler, Hoedt, Talley, Keely and Burns.)

Functional dyspepsia (FD) affects up to 15% of the population and is characterised by recurring upper gastrointestinal (GI) symptoms occurring in the absence of clinically identifiable pathology. Psychological stress is a key factor associated with the onset of FD and locally acting hypothalamic-pituitary-adrenal (HPA) axis hormones have been implicated in GI motility and barrier dysfunction. Recent pre-clinical work has identified mechanistic pathways linking corticotropin-releasing hormone (CRH) with the innate epithelial immune protein NLRP6, an inflammasome that has been shown to regulate GI mucus secretion. We recruited twelve FD patients and twelve healthy individuals to examine whether dysregulation of hypothalamic-pituitary adrenal (HPA) axis hormones and altered NLRP6 pathways were evident in the duodenal mucosa. Protein expression was assessed by immunoblot and immunohistochemistry in D2 duodenal biopsies. Plasma HPA axis hormones were assayed by ELISA and enteroid and colorectal cancer cell line cultures were used to verify function. FD patients exhibited reduced duodenal CRH-receptor 2, compared to non-GI disease controls, indicating a dysregulation of duodenal HPA signalling. The loss of CRH-receptor 2 correlated with reduced NLRP6 expression and autophagy function, processes critical for maintaining goblet cell homeostasis. In accordance, duodenal goblet cell numbers and mucin exocytosis was reduced in FD patients compared to controls. In vitro studies demonstrated that CRH could reduce NLRP6 in duodenal spheroids and promote mucus secretion in the HT29-MTX-E12 cell line. In conclusion, FD patients exhibit defects in the NLRP6-autophagy axis with decreased goblet cell function that may drive symptoms of disease. These features correlated with loss of CRH receptor 2 and may be driven by dysregulation of HPA signalling in the duodenum of FD patients., (Copyright © 2022 Elsevier Inc. All rights reserved.)

The US Food and Drug Administration hosted a workshop on July 21, 2021, to discuss the disease characteristics, natural history, and end points to assess treatment benefit in patients with eosinophilic gastrointestinal disorders (EGIDs) beyond eosinophilic esophagitis (EoE). Notably, EGIDs beyond EoE, such as eosinophilic gastritis, eosinophilic enteritis, and eosinophilic colitis, herein referred to as non-EoE EGIDs, are understudied relative to EoE. This workshop provided a forum for open discussion among stakeholders-medical professionals (including their societies and research groups), Food and Drug Administration representatives, an industry representative, and a patient representative-to facilitate drug development. Experts in many disciplines related to EGIDs, including allergy, immunology, epidemiology, gastroenterology, and pathology, and both adult and pediatric clinicians contributed. Herein, we discuss some of the insights of the material presented at the meeting and present perspectives on moving the field forward toward drug approval., (Copyright © 2021 American Academy of Allergy, Asthma & Immunology. All rights reserved.)

Objectives: To evaluate the role of Helicobacter pylori and other risk factors in recurrent aphthous stomatitis (RAS)., Methods: Patients with functional dyspepsia responded to questionnaires regarding demographic and clinical data, anxiety and depression, and a specific RAS questionnaire. They underwent upper digestive endoscopy and H. pylori evaluation., Results: 476 patients were included and of the 372 evaluated for H. pylori, 65.6% were H. pylori-positive. RAS was reported by 32.6% (155/476). In the bivariate analysis of the 372 patients evaluated for gastric H. pylori status, positive subjects had a lower RAS prevalence (29.9%; 73/244) than H. pylori-negative (41.4%; 53/128) (p = .026). Smoking (p = .005) and older age (p = .034) were also associated with a lower prevalence, while female gender (p = .032) and lower income (p = .046) presented higher RAS prevalence. In the multivariate analysis, H. pylori infection (p = .017), smoking (p = .001), and older age (p = .013) were protective factors, while lower income (p = .030) and anxiety (p = .042) were risk factors. In the multivariate analysis of all patients, female gender, lower income, and more schooling years were risk factors., Conclusions: An unexpected lower prevalence of RAS was found in H. pylori-positive patients. Smoking, sex, age, income, education, and anxiety were associated with RAS., (© 2021 Wiley Periodicals LLC.)

Background: An individual's drive to seek medical help remains a complex behavioural process, incorporating psychological, social and symptom-specific factors. Within irritable bowel syndrome (IBS), gastrointestinal symptoms only predict a small portion of the high healthcare-seeking experienced., Aim: To examine the moderating role of quality of life (QoL) domains on this relationship to help explain the variance observed., Methods: This is an analysis of a Swedish population-based prospective study of healthcare use over a 12-year period. At baseline, gastrointestinal symptoms were measured with the valid Gastrointestinal Symptom Rating Scale, and QoL via the SF-36. 1159 subjects (57% female; mean age 48.6 years) had their health records matched with the initial survey. 164 were classified as IBS by Rome II criteria. Negative binomial or logistic models were fit to evaluate the moderating effect of particular QoL domains on the relationship between gastrointestinal symptoms and prospective healthcare utilisation., Results: Gastrointestinal symptoms were associated with prospective healthcare use, but moderation in this relationship by particular QoL domains was not supported; most models did not reach statistical significance. Furthermore, the impact of IBS status did not alter the moderation hypotheses., Conclusions: Particular QoL domains did not impact the relationship between gastrointestinal symptoms on prospective healthcare seeking. Future research should continue to examine other psychological, social and symptom variables to identify predictors of high healthcare consumers in IBS., (© 2021 John Wiley & Sons Ltd.)

Background: Crohn's disease (CD), ulcerative colitis (UC), and indeterminate colitis are inflammatory bowel diseases (IBDs) that adversely affect the healthcare needs and quality of life (QoL) of people with IBD. The aim of this study was to explore the needs and perceptions of people with IBD in a primary care setting., Methods: This sequential explanatory mixed-methods study consisted of a cross-sectional survey (included validated tools), followed by semistructured interviews on participants' perceptions: IBD management, healthcare professionals, IBD care, flare management, and pharmacist's IBD roles., Results: Sixty-seven participants completed the survey, and 8 completed interviews. Quantitative findings : Age at diagnosis had significant association with medication nonadherence ( P = .04), QoL ( P = .04), and disease control ( P = .01) among the respondents. The odds of medication nonadherence were 8 times (adjusted odds ratio [AOR] = 8.04, 95% confidence interval [CI] = 1.08, 60.10) higher among younger participants aged <30 years. Those diagnosed with CD ( P = .02) reported more likely to have unfavorable perceptions of pharmacists' role in managing their IBD (AOR = 9.45, 95% CI = 1.57, 56.62) than those with UC and indeterminate colitis. Qualitative findings : General practitioners were considered the most important care provider and the first point of contact for patients in managing all aspects of IBD. Participants identified their key need to be timely access to specialized IBD care and found that other primary healthcare professionals lacked disease-specific knowledge for managing IBD., Conclusions: Primary healthcare professionals are well positioned but need targeted training to influence the needs of IBD patients. The specialty role of an IBD educator could complement existing services to deliver and address patient-specific care., (© The Author(s) 2022. Published by Oxford University Press on behalf of Crohn\'s & Colitis Foundation.)

Frequently, patients with functional gastrointestinal disorders (FGIDs) report intolerance of wheat products. We compared gastrointestinal symptoms, sensory function, psychiatric comorbidities, gut-homing immune cells, and duodenal mucosa-associated microbiome (d-MAM) in FGID patients and controls with and without self-reported wheat sensitivity (SR-NCWS). We recruited 40 FGID patients and 20 controls referred by GPs for treatment. Gastrointestinal/extraintestinal symptoms, visceral sensory function, psychological comorbidities, and SR-NCWS were assessed in a standardized approach. Peripheral gut homing T-cells (CD4 + α4 + β7 + CCR9 + /CD8 + α4 + β7 + CCR9 + ) were quantified, and the d-MAM was assessed by DNA sequencing for 46 subjects. Factors of bacterial genera were extracted utilizing factor analysis with varimax rotation and factors univariately associated with FGID or SR-NCWS included in a subsequent multivariate analysis of variance to identify statistically independent discriminators. Anxiety scores (p < .05) and increased symptom responses to a nutrient challenge (p < .05) were univariately associated with FGID. Gut homing T-cells were increased in FGID patients with SR-NCWS compared to other groups (p all <0.05). MANOVA revealed that anxiety (p = .03), visceral sensory function (p = 0.007), and a d-MAM factor comprise members of the Alloprevotella, Prevotella, Peptostreptococcus, Leptotrichia , and Veillonella lineages were significantly (p = .001) associated with FGID, while gut homing CD4 + α4 + β7 + CCR9 + T-cells were associated (p = .002) with SR-NCWS. Compared to controls, patients with and without SR-NCWS show that there are shifts in the amplicon sequence variants within specific bacterial genera between the FGID subgroups (particularly Prevotella and Streptococcus ) as well as distinct bacterial taxa discriminatory for the two different FGID subtypes. Compared to controls, both FGID patients with and without SR-NCWS have an increased symptom response to a standardized nutrient challenge and increased anxiety scores. The FGID patients with SR-NCWS - as compared to FGID without SR-NCWS (and controls without SR-NCWS) - have increased gut homing T-cells. The d-MAM profiles suggest species and strain-based variations between the two FGID subtypes and in comparison to controls.

Background: Functional gastrointestinal disorders (FGIDs) are diagnosed according to expert consensus criteria based on recall of symptoms over periods of 3 months or longer. Whether the expert opinion concords with underlying disease process and whether individual recall is accurate are both in doubt. This study aimed to identify naturally occurring clusters of individuals with respect to symptom pattern, evaluate their significance, compare cluster profiles with expert opinion and evaluate their temporal stability., Methods: As part of a random population study of FGID-related symptoms, we first explored the use of prospective stool and symptom diaries combined with empirical grouping of individuals into clusters using nonhierarchical cluster analysis., Results: The analysis identified two clusters of individuals, one of which was characterized by elevated scores on all domains of symptoms (26% of the sample) and one that was low to average on all domains (74% of the sample). Cluster membership was found to be stable over a long interval. Clusters were found to differ on most domains of quality-of-life (d = 0.46-0.74), self-rated health (d = -0.42) and depression (d = -0.42) but not anxiety. Prevalence of clinically diagnosed irritable bowel syndrome (IBS) was higher in the more impacted cluster (33%) compared with the healthy cluster (13%; P < 0.0001)., Conclusion: A naturalistic classification of individuals challenges consensus criteria in showing that some IBS individuals have a symptom experience not unlike health. The proposed approach has demonstrated temporal stability over time, unlike consensus criteria. A naturalistic disease classification system may have practical advantages over consensus criteria when supported by a decision-analytic system., (Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved.)

Debate continues as to whether an attentional bias towards threat displayed by sufferers of functional gastrointestinal disorders (FGIDs) is conscious and, thus, more amenable to change through psychological therapy. We compared the amplitudes of early (unconscious) and later (conscious) electroencephalographic (EEG) event-related potentials following silent reading of symptom-related, emotionally neutral, and emotionally negative nouns across two participant groups: 30 female FGID-sufferers who met diagnostic criteria for irritable bowel syndrome or functional dyspepsia, and 30 female healthy controls. Analogous indices based on alpha desynchronization were also examined, as were correlations between the EEG-based indices and a range of psychosocial variables. FGID-sufferers displayed marginally significantly higher occipital EPN amplitudes for all nouns, indicating marginally higher levels of unconscious attention in the task. FGID-sufferers also displayed, for negative as compared to neutral nouns, significantly lower central N400 amplitudes indicative of higher conscious attention. The result was only apparent in post-hoc pairwise comparisons, however. Uniquely among FGID-sufferers, central N400 was strongly negatively correlated with a range of negative psychosocial traits and states. The findings provide preliminary evidence of hypervigilance to general (as opposed to symptom-specific) threat among FGID-sufferers. Amidst concerns over Type I error, recommendations are made for fine-tuning the operationalisation of unconscious and conscious attentional bias in this population., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Functional gastrointestinal disorders (FGIDs) encompass a range of complex conditions with similar clinical characteristics and no overt pathology. Recent recognition of sub-clinical pathologies in FGIDs, in conjunction with physiological and biochemical abnormalities including increased intestinal permeability, microbial profile alterations, differences in metabolites and extra-intestinal manifestations of disease, call into question the designation of these conditions as 'functional'. This is despite significant heterogeneity in both symptom profile and specifics of reported physiological abnormalities hampering efforts to determine defined mechanisms that drive onset and chronicity of symptoms. Instead, the literature demonstrates these conditions are disorders of homeostatic imbalance, with disruptions in both host and microbial function and metabolism. This imbalance is also associated with extraintestinal abnormalities including psychological comorbidities and fatigue that may be a consequence of gastrointestinal disruption. Given the exploitation of such abnormalities will be crucial for improved therapeutic selection, an enhanced understanding of the relationship between alterations in function of the gastrointestinal tract and the response of the immune system is of interest in identifying mechanisms that drive FGID onset and chronicity. Considerations for future research should include the role of sex hormones in regulating physiological functions and treatment responses in patients, as well as the importance of high-level phenotyping of clinical, immune, microbial and physiological parameters in study cohorts. There is opportunity to examine the functional contribution of the microbiota and associated metabolites as a source of mechanistic insight and targets for therapeutic modulation., (© 2021 The Authors. The Journal of Physiology © 2021 The Physiological Society.)

Symptoms of irritable bowel syndrome (IBS) characteristically fluctuate over time. We aimed to review the natural history of IBS and IBS subgroups including bowel habit disturbances, and the overlap of IBS with other gastrointestinal disorders. The community incidence of IBS is approximately 67 per 1000 person years. The prevalence of IBS is stable over time because symptoms fluctuate and there is a portion who experience resolution of their GI symptoms similar in number to those developing new-onset IBS. The proportion who report resolution of symptoms varies amongst population-based studies from 17% to 55%. There is evidence of substantial movement between subtypes of IBS. For example in a clinical trial cohort, only one in four patients retained their baseline classification throughout the study periods, two in three moved between IBS-C (constipation) and IBS-M (mixed), while over half switched between IBS-D (diarrhoea) and IBS-M. The least stable group was IBS-M. There are very limited data on drivers of bowel habit change in IBS. There are emerging evidence fluctuations in intestinal immune activity might account for symptom variability over time. It is of clinical importance to recognise the substantial overlap of IBS symptoms with other gastrointestinal syndromes including gastro-oesophageal reflux disease. This is important to ensure the correct clinical diagnosis of IBS is made and patients are not over investigated. Knowledge of the natural history, stability of subgroups and overlap of IBS with other gastrointestinal conditions should be considered in therapeutic decision making., (© 2021 John Wiley & Sons Ltd.)

Background: Rumination syndrome is a functional gastroduodenal disorder characterised by effortless regurgitation of recently ingested food. Emerging evidence reports duodenal eosinophilic inflammation in a subset, suggesting a shared pathophysiology with functional dyspepsia (FD)., Aim: To assess the clinical features of rumination syndrome and FD in a community-based study., Methods: We mailed a survey assessing gastrointestinal symptoms, diet and psychological symptoms to 9835 residents of Olmsted County, MN, USA in 2017-2018; diagnostic codes were obtained from linked clinical records. The two disorders were assessed as mutually exclusive in 'pure' forms with a separate overlap group, all compared to a control group not meeting criteria for either. Prevalence of associations, and univariate and independent associations with predictors were assessed by logistic regression., Results: Prevalence of rumination syndrome and FD were 5.8% and 7.1%, respectively; the overlap was 3.83-times more likely than expected by chance. Independent predictors for rumination (odds ratio (OR), 95% confidence interval (CI)) were female gender (1.79, 1.21-2.63), smoking (1.89, 1.28-2.78), gluten-free diet (1.58, 1.14-2.19), allergic rhinitis (1.45, 1.01-2.08) and depression (1.10, 1.05-1.16). FD was independently associated with female gender, depression, non-coeliac wheat sensitivity, migraine, irritable bowel syndrome and somatic symptoms. A similar reported efficacy (≥54%) of low fat or dairy-free diets was found with both disorders (P = 0.53 and P = 1.00, respectively). The strongest independent associations with overlapping FD and rumination syndrome were a history of rheumatoid arthritis (3.93, 1.28-12.06) and asthma (3.02, 1.44-6.34)., Conclusion: Rumination syndrome overlaps with FD with a shared risk factor profile, suggesting a common pathophysiology., (© 2021 John Wiley & Sons Ltd.)

Objective: Irritable bowel syndrome (IBS) is a chronic disorder associated with an abnormal gastrointestinal microbiome. Microbiome-host interactions are known to influence organ function including in the central nervous system; thus, we sought to identify whether IBS may be a risk factor for the development of glaucoma., Design: Two prospective cohort studies., Subjects: The 1958 United Kingdom Birth Cohort (UKBC; 9091 individuals) and the Danish National Registry of Patients (DNRP; 62,541 individuals with IBS and 625,410 matched general population cohort members)., Methods: In the UKBC, participants were surveyed throughout life (including at ages 42 and 50). The DNRP contains records of hospital-based contacts and prescription data from the national prescription database., Main Outcome Measure: The main outcome measure was incidence of glaucoma. In the UKBC, incident glaucoma at age 50 (n = 48) was determined through comparison of survey responses at ages 42 and 50 years. In the DNRP, glaucoma was assessed by hospital diagnosis (n = 1510), glaucoma surgery (n = 582) and initiation of glaucoma medications (n = 1674)., Results: In the UKBC, the odds ratio (OR) of developing glaucoma between ages 42 and 50 in persons with a chronic IBS diagnosis was increased [OR: 5.84, 95% confidence interval (CI): 2.26-15.13]. People with an IBS diagnosis in the DNRP had a hazard ratio (HR) of 1.35 for developing physician-diagnosed glaucoma (95% CI: 1.16-1.56), an HR of 1.35 for undergoing glaucoma surgery (95% CI: 1.06-1.70) and an HR of 1.19 for initiating glaucoma medication (95% CI: 1.03-1.38)., Conclusions: In two large European cohort studies, IBS is a risk factor for glaucoma., (© 2021 The Authors. United European Gastroenterology Journal published by Wiley Periodicals LLC on behalf of United European Gastroenterology.)

Introduction: While the etiopathogenesis of functional gastrointestinal disorders (FGIDs) is not completely understood, alterations of the intestinal microbiome have been observed. Antibiotics can induce dysbiosis, but whether antibiotics are a risk factor for the onset of FGIDs is uncertain. Antibiotics have been reported as both a risk factor for new onset FGID but also as a therapy for existing FGID. This study aimed to estimate the fraction of cases where antibiotics provoked the onset of FGID., Method: Electronic medical records were obtained from general practices (primary care) in the United Kingdom. Dates of antibiotic prescription (AP) were compared with first date of FGID diagnosis and contrasted across three prevalent FGIDs and controls without gastrointestinal disorders., Results: There were 10,926 GI healthy controls, 4326 IBS alone, 3477 FD alone, 340 chronic constipation and 4402 with overlap of multiple conditions. Both the prevalence of AP and rate were higher in FGID patients and increased with diagnosis of multiple FGIDs. 7%-14% of FGID patients were prescribed their first recorded antibiotic in the 12 months prior to their first FGID diagnosis and 20%-33% were prescribed an antibiotic in the same period. Differences between FGID groups were not accounted for by social deprivation and only rate of AP was moderated by social deprivation. In contrast, only 5%-10% of patients ever had a gastrointestinal infection recorded and only 1.5%-3.5% prior to their first FGID diagnosis., Conclusion: These data indicate that antibiotics are prescribed prior to FGID diagnosis in a significant minority of care-seeking FGID patients, opening the potential for this medication to contribute to the pathophysiology. APs appears to mostly be for non-gastrointestinal conditions., (© 2021 The Authors. United European Gastroenterology Journal published by Wiley Periodicals LLC on behalf of United European Gastroenterology.)

Introduction: The concept of gut-to-brain communication via microbial or inflammatory pathways is gaining increased attention but genuine pathology directly linking gut perturbation to anxiety is lacking. We hypothesized that duodenal eosinophilia, as known to occur in functional dyspepsia (FD), may be an underlying cause of anxiety and may help explain the striking association between FD and anxiety., Methods: Randomly selected subjects from the national population register of Sweden completed the validated Abdominal Symptom Questionnaire; 1000 completed esophagogastroduodenoscopy and the Hospital Anxiety and Depression Scale questionnaire. Duodenal biopsies were obtained from 1 st (D1) and 2 nd portion (D2). Eligible subjects who underwent endoscopy (n = 887) were invited to participate in a 10-year follow-up study with the same questionnaires. Among endoscopy normal subjects, FD was identified by Rome criteria, and controls were symptom free. Duodenal eosinophilia was based on pre-defined cut-offs. Finding are reported as odds ratios (ORs) with 95% confidence interval and p-value., Results: The study population comprised 89 cases with FD and 124 healthy controls (mean age 62 years, SD 12, 34% male). Clinical anxiety at follow-up was elevated in those with D1 eosinophilia at baseline considering either new-onset anxiety (OR = 4.5, 95% CI 0.8, 23.8; p = 0.08) or follow-up anxiety adjusting for baseline anxiety (OR = 4.51 (95% CI 1.03, 19.81; p = 0.046)., Conclusion: Duodenal eosinophilia may potentially be a mechanism linked to anxiety independent of FD., (© 2021 John Wiley & Sons Ltd.)

Patients suffering functional dyspepsia symptoms have been shown to possess a greater relative abundance of Streptococcus compared to asymptomatic controls. Here, we describe the isolation and genomic features of a new Streptococcus isolate, from the duodenal tissue of a subject reporting dyspeptic symptoms, taxonomically assigned to Streptococcus salivarius and designated strain AGIRA0003.

Bile acids are metabolites involved in nutrient absorption and signaling with levels influenced by dietary intake, metabolic processes, and the gut microbiome. We aimed to quantify 23 bile acids in fecal samples to ascertain if concentrations differed between healthy participants and those with functional gut disorders. Fecal bile acids were measured using liquid chromatography-mass spectrometry (LC-MS) in the COMFORT (The Christchurch IBS cohort to investigate mechanisms for gut relief and improved transit) cohort of 250 participants with Rome IV IBS (IBS-constipation (C), IBS-diarrhea (D), IBS-mixed (M)), functional gut disorders (functional constipation (FC), functional diarrhea (FD)) and healthy controls (FC n = 35, FD n = 13, IBS-C n = 24, IBS-D n = 52, IBS-M n = 29, and control n = 97). Dietary information was recorded to ascertain three-day dietary intake before fecal samples were collected. Fecal bile acid concentrations, predominantly primary bile acids, were significantly different between all functional gut disorder participants and healthy controls (CDCA p = 0.011, CA p = 0.003) and between constipation (FC + IBS-C) and diarrhea (FD + IBS-D) groups (CDCA p = 0.001, CA p = 0.0002). Comparison of bile acids between all functional groups showed four metabolites were significantly different, although analysis of combined groups (FC + IBS-C vs. FD + IBS-D) showed that 10 metabolites were significantly different. The bile acid profiles of FD individuals were similar to those with IBS-D, and likewise, those with FC were similar to IBS-C. Individuals with a diarrhea phenotype (FD + IBS-D) had higher concentrations of bile acids compared to those with constipation (FC + IBS-C). Bile acid metabolites distinguish between individuals with functional gut disorders and healthy controls but are similar in constipation (or diarrhea) whether classified as IBS or not.

Background: Due to important biases, conventional end-of-day and end-of-week assessment methods of gastrointestinal symptoms in functional dyspepsia (FD) are considered suboptimal. Real-time symptom assessment based on the experience sampling method (ESM) could be a more accurate measurement method. This study aimed to evaluate validity and reliability of an ESM-based patient-reported outcome measure (PROM) for symptom assessment in FD., Methods: Thirty-five patients with FD (25 female, mean age 44.7 years) completed the ESM-based PROM (a maximum of 10 random moments per day) and an end-of-day symptom diary for 7 consecutive days. On day 7, end-of-week questionnaires were completed including the Nepean Dyspepsia Index (NDI) and Patient Assessment of Gastrointestinal Symptom Severity Index (PAGI-SYM)., Key Results: Experience sampling method and corresponding end-of-day scores for gastrointestinal symptoms were significantly associated (ICCs range 0.770-0.917). However, end-of-day scores were significantly higher (Δ0.329-1.031) than mean ESM scores (p < 0.05). Comparing ESM with NDI and PAGI-SYM scores, correlations were weaker (Pearson's r range 0.467-0.846). Cronbach's α coefficient was good for upper gastrointestinal symptoms (α = 0.842). First half-week and second half-week scores showed very good consistency (ICCs range 0.913-0.975)., Conclusion and Inferences: Good validity and reliability of a novel ESM-based PROM for assessing gastrointestinal symptoms in FD patients was demonstrated. Moreover, this novel PROM allows to evaluate individual symptom patterns and can evaluate interactions between symptoms and environmental/contextual factors. ESM has the potential to increase patients' disease insight, provide tools for self-management, and improve shared decision making. Hence, this novel tool may aid in the transition toward personalized health care for FD patients., (© 2021 The Authors. Neurogastroenterology & Motility published by John Wiley & Sons Ltd.)

Whilst intraepithelial lymphocytes (IELs) are considered normal within the distal esophageal mucosa, they have an increasingly recognised role in the pathogenesis of reflux esophagitis, and IEL quantification establishes the diagnosis of lymphocytic esophagitis. Knowledge regarding the upper limit of a normal IEL count in health is lacking. We studied 117 non-healthcare seeking adult volunteers from a random community sample (the Kalixanda study) with esophageal biopsies 2 cm above the gastroesophageal junction. Subjects were divided into four groups based on the presence or absence of gastro-esophageal reflux symptoms and/or esophagitis on endoscopy. Asymptomatic subjects with no endoscopic esophagitis were selected as controls, and the cell counts in this group were used to define the upper limit of normal of IELs, eosinophils and neutrophils. The entire sample was used to identify independent predictors of increased cellular counts by logistic regression analysis. None of the healthy controls had an IEL count of more than three per five high power fields (HPF), and therefore this was considered as the upper limit of normal; no controls had eosinophils or neutrophils in esophageal biopsies. Independent predictors of an elevated IEL count were spongiosis on histology (OR 11.17, 95% CI 3.32-37.58, P < 0.01) and current smoking (OR 4.84, 95% CI 1.13-2.71, P = 0.03). A receiver operating characteristics analysis concluded that a threshold of 3 IELs/5HPFs performs best in predicting reflux symptoms when a normal esophageal mucosa is visualized on endoscopy (sensitivity = 100.0%, specificity = 35.2%). The healthy esophageal mucosa does not contain more than three IELs per five HPF in the distal esophagus., (Copyright © 2021. Published by Elsevier Inc.)

The European Society for Neurogastroenterology and Motility's (ESNM) consensus document on functional dyspepsia (FD) has provided a critical review of the evidence for 36 statements highly relevant to the diagnosis and treatment of FD. We provide here our expert opinion on the North American, Australian and Asian assessments of the same topics discussed, and provide evidence where the ESNM consensus may deviate from those in the other continents. New and exciting data about the pathogenesis of FD are emerging including the possible central role of duodenal micro-inflammation (most notably eosinophilic duodenitis and intestinal mast cell disease), but this is a very dynamic field with several gaps remaining in our understanding that are summarized in this review. Identification of non-invasive biomarkers and testing of targeted therapies, including assessing the benefits of multidisciplinary teams in the management of FD, should be future priorities., (© 2021 John Wiley & Sons Ltd.)

BACKGROUND & AIMS: Nitric oxide, a major inhibitory nonadrenergic, noncholinergic neurotransmitter that relaxes smooth muscle, may be implicated in the pathophysiology of visceral hypersensitivity in irritable bowel syndrome (IBS). Impaired bioavailability of the nitric oxide precursor molecule L-arginine and higher concentrations of methylarginines (endogenous inhibitors of nitric oxide synthesis) are known to impair nitric oxide synthesis in numerous gastrointestinal cell types. We therefore examined serum concentrations of L-arginine and the methylarginines in a nested case-control study, to assess whether these factors are associated with adult IBS., Methods: Data on clinical characteristics, methylarginines, and L-arginine (measured using LC-MS/MS) were collected from a random population-based cohort of Australian adults (median age = 64 years; IQR = 60-70). Cases of IBS, defined according to Rome III criteria (N = 156), and controls (N = 332) were identified from within the cohort at the 5-year follow-up., Results: In adjusted logistic regression analyses, L-arginine, asymmetric dimethylarginine, symmetric dimethylarginine, L-arginine/asymmetric dimethylarginine ratio, and Kessler-10 psychological distress scores were significantly associated with IBS (p < 0.05). [Correction added on 18 September 2021, after first online publication: In the preceding sentence, the value (p > 0.05) has been changed to (p < 0.05)]. Similar results were found for IBS subtypes. Higher serum L-arginine concentration had the strongest association with IBS diagnosis, with an odds ratio of 9.03 for those with serum L-arginine at the 75th (84 μmol/L) versus 25th (46 μmol/L) percentile (95% CI: 5.99-13.62). L-arginine had the best discriminative ability with a bias-adjusted area under the receiver operator characteristic curve of 0.859., Conclusions: Higher serum concentrations of L-arginine and endogenous methylarginines are strongly associated with IBS in adults., (© 2021 The Authors. United European Gastroenterology Journal published by Wiley Periodicals LLC. on behalf of United European Gastroenterology.)

Competing Interests: Disclosures: Since 2020, Dr Talley reports receiving nonfinancial support from HVN National Science Challenge NZ, Anatara Life Sciences, Allakos (gastric eosinophilic disease), Bayer (IBS), Planet Innovation (gas capsule for IBS), Viscera Labs (IBS-predominant diarrhea), Dr Falk Pharma (eosinophilic esophagitis), Glutagen (celiac disease), ISOThrive (esophageal microbiome), Rose Pharma, and BluMaiden outside of submitted work. In addition, he has a patent for the Nepean Dyspepsia Index, licensed biomarkers for IBS, a patent licensing the Talley Bowel Disease Questionnaire to Mayo/ himself, a Nestec European patent, and a Singapore provisional patent for “Microbiota Modulation of BDNF Tissue Repair Pathway.” He is also supported by funding from the National Health and Medical Research Council (NHMRC) to the Centre for Research Excellence in Digestive Health, and he holds an NHMRC investigator grant.

Background: Psychological distress, strongly associated with functional gastrointestinal disorders (FGIDS), likely plays a central role in the pathophysiology. The role of sleep disturbances in FGIDs is unclear, and an association with psychological factors is uncertain., Aim: To determine whether sleep disturbances are associated with irritable bowel syndrome (IBS) and functional dyspepsia (FD) and if a potential association is explained by psychological distress., Methods: Adult sample randomly selected from a region in New South Wales, Australia in 2015 who returned a follow-up mail survey in 2018 (response rate, 60.5%) that contained questions on IBS, FD, sleep (MOS-Sleep Scale) and psychological distress (Kessler 6 scale)., Results: Among this population, 10.4% (95% CI 8.8-12.2) and 17.9% (95% CI 15.9-20.1) met Rome III criteria for IBS and FD, respectively. The prevalence of any sleep disturbance at least most of the time was common, with a significantly higher prevalence in FGID (IBS and/or FD) compared with the remaining population (41.8% vs 32.2%, P = 0.003). The total sleep problem index was significantly higher for IBS (OR = 1.71 [95% CI 1.29-2.27], P < 0.0001) (IBS-diarrhoea predominant and IBS-mixed but not IBS-constipation) and FD (OR = 1.80 [1.43-2.26], P < 0.0001) (both epigastric pain syndrome and postprandial distress syndrome) even after adjusting for age, sex and psychological distress., Conclusion: Both IBS and FD, and most of their major subtypes except IBS-C, are associated with a range of sleep disturbances. These sleep problems do not appear to be explained by psychological factors and may play an independent role in the pathophysiology., (© 2021 John Wiley & Sons Ltd.)

Background: Patients presenting with gastrointestinal symptoms can be challenging in terms of determining etiology and management strategies. Identifying likely organic pathology is important since it can be treated and may result in further, long-term harm to the patient if not treated. Currently, organic pathology is often identified via invasive procedures such as endoscopy or referral to a medical imaging service. We report on an approach that offers a first step at identifying patients with an organic gastrointestinal disease based on the SAGIS, a validated symptom questionnaire., Methods: 8,922 patients referred to a tertiary care hospital were classified as having either functional gastrointestinal disease or an organic gastrointestinal disease. A model was developed to distinguish organic from functional symptoms on one random split half of the sample and validated on the other half. The incremental benefit of including psychological conditions and extra-gastrointestinal conditions was also evaluated., Key Results: Functional gastrointestinal patients scored higher on average than organic patients on all dimensions of the SAGIS and reported higher rates of psychological and extra-gastrointestinal conditions. All five dimensions of the SAGIS provided statistically independent discrimination of organic from functional diagnoses with good overall discrimination (AUC = 0.75). However, there was no noticeable incremental benefit of adding either psychological or extra-gastrointestinal conditions. Model performance was highly reproducible., Conclusions and Inferences: The proposed algorithm for identifying likely organic gastrointestinal disease applied to symptoms as recorded in the SAGIS questionnaire provides a useful tool for the clinician in deciding what or if further diagnostic testing is required., (© 2021 John Wiley & Sons Ltd.)

In this study, the intestinal permeability of metal(loid)s (MLs) such as arsenic (As), cadmium (Cd), lead (Pb) and mercury (Hg) was examined, as influenced by gut microbes and chelating agents using an in vitro gastrointestinal/Caco-2 cell intestinal epithelium model. The results showed that in the presence of gut microbes or chelating agents, there was a significant decrease in the permeability of MLs (As-7.5%, Cd-6.3%, Pb-7.9% and Hg-8.2%) as measured by apparent permeability coefficient value (P app ), with differences in ML retention and complexation amongst the chelants and the gut microbes. The decrease in ML permeability varied amongst the MLs. Chelating agents reduce intestinal absorption of MLs by forming complexes thereby making them less permeable. In the case of gut bacteria, the decrease in the intestinal permeability of MLs may be associated to a direct protection of the intestinal barrier against the MLs or indirect intestinal ML sequestration by the gut bacteria through adsorption on bacterial surface. Thus, both gut microbes and chelating agents can be used to decrease the intestinal permeability of MLs, thereby mitigating their toxicity., (© 2021. The Author(s).)

Background: It is uncertain if functional dyspepsia (FD) or irritable bowel syndrome (IBS) are linked to smoking, and smoking cessation is not part of the routine advice provided to these patients., Aim: To assess if smoking is an independent risk factor for FD and IBS., Methods: Three population-based endoscopy studies in Sweden with 2560 community individuals in total (mean age 51.5 years, 46% male). IBS (14.9%), FD (33.5%), and associated symptoms were assessed using the validated abdominal symptom questionnaire, and smoking (17.9%) was obtained from standardised questions during a clinic visit. The effect of smoking on symptom status was analysed in an individual person data meta-analysis using mixed effect logistic regression, adjusted for snuffing, age and sex., Results: Individuals smoking cigarettes reported significantly higher odds of postprandial distress syndrome (FD-PDS) (OR 10-19 cig/day = 1.42, 95% CI 1.04-1.98 P = 0.027, OR ≥20 cig/day = 2.16, 95% CI 1.38-3.38, P = 0.001) but not epigastric pain. Individuals smoking 20 or more cigarettes per day reported significantly higher odds of IBS-diarrhoea (OR = 2.40, 95% CI 1.12-5.16, P = 0.025), diarrhoea (OR = 2.01, 95%CI 1.28-3.16, P = 0.003), urgency (OR = 2.21, 95%CI 1.41-3.47, P = 0.001) and flatus (OR = 1.77, 95%CI 1.14-2.76, P = 0.012) than non-smokers. Smoking was not associated with IBS-constipation or IBS-mixed., Conclusion: Smoking is an important environmental risk factor for postprandial distress syndrome, the most common FD subgroup, with over a twofold increased odds of PDS in heavy smokers. The role of smoking in IBS-diarrhoea, but not constipation, is also likely important., (© 2021 John Wiley & Sons Ltd.)