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ObjectiveOver half of patients with IBS have either diarrhoea (IBS-D) or a mixed stool pattern (IBS-M). The relative efficacy of licenced pharmacological therapies is unclear in the absence of head-to-head trials. We conducted a network meta-analysis to resolve this uncertainty.DesignWe searched MEDLINE, Embase, Embase Classic, the Cochrane central register of controlled trials, and Clinicaltrials.gov through January 2019 to identify randomised controlled trials (RCTs) assessing the efficacy of licenced pharmacological therapies (alosetron, eluxadoline, ramosetron and rifaximin) in adults with IBS-D or IBS-M. Trials included in the analysis reported a dichotomous assessment of overall response to therapy, and data were pooled using a random effects model. Efficacy and safety of all pharmacological therapies were reported as a pooled relative risk with 95% CIs to summarise the effect of each comparison tested. Treatments were ranked according to their p score.ResultsWe identified 18 eligible RCTs (seven alosetron, five ramosetron, two rifaximin and four eluxadoline), containing 9844 patients. All were superior to placebo for the treatment of IBS-D or IBS-M at 12 weeks, according to the Food and Drug Administration (FDA)-recommended endpoint for trials in IBS. Alosetron 1 mg twice daily was ranked first for efficacy, based on the FDA-recommended composite endpoint of improvement in both abdominal pain and stool consistency, effect on global symptoms of IBS and effect on stool consistency. Ramosetron 2.5µg once daily was ranked first for effect on abdominal pain. Total numbers of adverse events were significantly greater with alosetron 1 mg twice daily and ramosetron 2.5µg once daily, compared with placebo. Rifaximin 550 mg three times daily ranked first for safety. Constipation was significantly more common with all drugs, except rifaximin 550 mg three times daily.ConclusionIn a network meta-analysis of RCTs of pharmacological therapies for IBS-D and IBS-M, we found all drugs to be superior to placebo, but alosetron and ramosetron appeared to be the most effective.

ObjectivesNational guidelines for the management of irritable bowel syndrome (IBS) recommend that psychological therapies should be considered, but their relative efficacy is unknown, because there have been few head-to-head trials. We performed a systematic review and network meta-analysis to try to resolve this uncertainty.DesignWe searched the medical literature through January 2020 for randomised controlled trials (RCTs) assessing efficacy of psychological therapies for adults with IBS, compared with each other, or a control intervention. Trials reported a dichotomous assessment of symptom status after completion of therapy. We pooled data using a random effects model. Efficacy was reported as a pooled relative risk (RR) of remaining symptomatic, with a 95% CI to summarise efficacy of each comparison tested, and ranked by therapy according to P score.ResultsWe identified 41 eligible RCTs, containing 4072 participants. After completion of therapy, the psychological interventions with the largest numbers of trials, and patients recruited, demonstrating efficacy included self-administered or minimal contact cognitive behavioural therapy (CBT) (RR 0.61; 95% CI 0.45 to 0.83, P score 0.66), face-to-face CBT (RR 0.62; 95% CI 0.48 to 0.80, P score 0.65) and gut-directed hypnotherapy (RR 0.67; 95% CI 0.49 to 0.91, P score 0.57). After completion of therapy, among trials recruiting only patients with refractory symptoms, group CBT and gut-directed hypnotherapy were more efficacious than either education and/or support or routine care, and CBT via the telephone, contingency management, CBT via the internet and dynamic psychotherapy were all superior to routine care. Risk of bias of trials was high, with evidence of funnel plot asymmetry; the efficacy of psychological therapies is therefore likely to have been overestimated.ConclusionsSeveral psychological therapies are efficacious for IBS, although none were superior to another. CBT-based interventions and gut-directed hypnotherapy had the largest evidence base and were the most efficacious long term.Trial registration numberThe study protocol was published on the PROSPERO international prospective register of systematic reviews (registration number CRD 42020163246).

Objective The commensal microbiota, host immunity and metabolism participate in a signalling network, with diet influencing each component of this triad. In addition to diet, many elements of a modern lifestyle influence the gut microbiota but the degree to which exercise affects this population is unclear. Therefore, we explored exercise and diet for their impact on the gut microbiota. Design Since extremes of exercise often accompany extremes of diet, we addressed the issue by studying professional athletes from an international rugby union squad. Two groups were included to control for physical size, age and gender. Compositional analysis of the microbiota was explored by 16S rRNA amplicon sequencing. Each participant completed a detailed food frequency questionnaire. Results As expected, athletes and controls differed significantly with respect to plasma creatine kinase (a marker of extreme exercise), and inflammatory and metabolic markers. More importantly, athletes had a higher diversity of gut micro-organisms, representing 22 distinct phyla, which in turn positively correlated with protein consumption and creatine kinase. Conclusions The results provide evidence for a beneficial impact of exercise on gut microbiota diversity but also indicate that the relationship is complex and is related to accompanying dietary extremes.

Background Intestinal homoeostasis is dependent on immunological tolerance to the microbiota. Objective To (1) determine if a probiotic could induce Foxp3 T cells in humans; (2) to elucidate the molecular mechanisms, which are involved in the induction of Foxp3 T cells by human dendritic cells. Design Cytokine secretion and Foxp3 expression were assessed in human volunteers following Bifidobacterium infantis feeding. Monocyte-derived dendritic cells (MDDCs), myeloid dendritic cells (mDCs) and plasmacytoid dendritic cells (pDCs) were incubated in vitro with B infantis and autologous lymphocytes. Transcription factor expression, costimulatory molecule expression, cytokine secretion, retinoic acid and tryptophan metabolism were analysed. Results Volunteers fed B infantis displayed a selective increase in secretion of interleukin (IL)-10 and enhanced Foxp3 expression in peripheral blood. In vitro, MDDCs, mDCs and pDCs expressed indoleamine 2,3-dioxygenase and secreted IL-10, but not IL-12p70, in response to B infantis . MDDC and mDC IL-10 secretion was Toll-like receptor (TLR)-2/6 dependent, while pDC IL-10 secretion was TLR-9 dependent. In addition, MDDCs and mDCs expressed RALDH2, which was TLR-2 and DC-SIGN dependent. B infantis -stimulated MDDCs, mDCs and pDCs induced T cell Foxp3 expression. TLR-2, DC-SIGN and retinoic acid were required for MDDC and mDC induction of Foxp3 T cells, while pDCs required indoleamine 2,3-dioxygenase. Conclusions B infantis administration to humans selectively promotes immunoregulatory responses, suggesting that this microbe may have therapeutic utility in patients with inflammatory disease. Cross-talk between multiple pattern-recognition receptors and metabolic pathways determines the innate and subsequent T regulatory cell response to B infantis . These findings link nutrition, microbiota and the induction of tolerance within the gastrointestinal mucosa.

Background and aims Irritable bowel syndrome (IBS) is a common functional gastrointestinal disorder that may be triggered by enteric pathogens and has also been linked to alterations in the microbiota and the host immune response. The authors performed a detailed analysis of the faecal microbiota in IBS and control subjects and correlated the findings with key clinical and physiological parameters. Design The authors used pyrosequencing to determine faecal microbiota composition in 37 IBS patients (mean age 37 years; 26 female subjects; 15 diarrhoea-predominant IBS, 10 constipation-predominant IBS and 12 alternating-type IBS) and 20 age- and gender-matched controls. Gastrointestinal and psychological symptom severity and quality of life were evaluated with validated questionnaires and colonic transit time and rectal sensitivity were measured. Results Associations detected between microbiota composition and clinical or physiological phenotypes included microbial signatures associated with colonic transit and levels of clinically significant depression in the disease. Clustering by microbiota composition revealed subgroups of IBS patients, one of which (n=15) showed normal-like microbiota composition compared with healthy controls. The other IBS samples (n=22) were defined by large microbiota-wide changes characterised by an increase of Firmicutes -associated taxa and a depletion of Bacteroidetes -related taxa. Conclusions Detailed microbiota analysis of a well-characterised cohort of IBS patients identified several clear associations with clinical data and a distinct subset of IBS patients with alterations in their microbiota that did not correspond to IBS subtypes, as defined by the Rome II criteria.

Background and Aims Increased efficiency of energy harvest, due to alterations in the gut microbiota (increased Firmicutes and decreased Bacteroidetes ), has been implicated in obesity in mice and humans. However, a causal relationship is unproven and contributory variables include diet, genetics and age. Therefore, we explored the effect of a high-fat (HF) diet and genetically determined obesity ( ob/ob ) for changes in microbiota and energy harvesting capacity over time. Methods Seven-week-old male ob/ob mice were fed a low-fat diet and wild-type mice were fed either a low-fat diet or a HF-diet for 8 weeks (n=8/group). They were assessed at 7, 11 and 15 weeks of age for: fat and lean body mass (by NMR); faecal and caecal short-chain fatty acids (SCFA, by gas chromatography); faecal energy content (by bomb calorimetry) and microbial composition (by metagenomic pyrosequencing). Results A progressive increase in Firmicutes was confirmed in both HF-fed and ob/ob mice reaching statistical significance in the former, but this phylum was unchanged over time in the lean controls. Reductions in Bacteroidetes were also found in ob/ob mice. However, changes in the microbiota were dissociated from markers of energy harvest. Thus, although the faecal energy in the ob/ob mice was significantly decreased at 7 weeks, and caecal SCFA increased, these did not persist and faecal acetate diminished over time in both ob/ob and HF-fed mice, but not in lean controls. Furthermore, the proportion of the major phyla did not correlate with energy harvest markers. Conclusion The relationship between the microbial composition and energy harvesting capacity is more complex than previously considered. While compositional changes in the faecal microbiota were confirmed, this was primarily a feature of high-fat feeding rather than genetically induced obesity. In addition, changes in the proportions of the major phyla were unrelated to markers of energy harvest which changed over time. The possibility of microbial adaptation to diet and time should be considered in future studies.

Introduction Probiotics may benefit irritable bowel syndrome (IBS) symptoms, but randomised controlled trials (RCTs) have been conflicting; therefore a systematic review was conducted. Methods MEDLINE (1966 to May 2008), EMBASE (1988 to May 2008) and the Cochrane Controlled Trials Register (2008) electronic databases were searched, as were abstracts from DDW (Digestive Diseases Week) and UEGW (United European Gastroenterology Week), and authors were contacted for extra information. Only parallel group RCTs with at least 1 week of treatment comparing probiotics with placebo or no treatment in adults with IBS according to any acceptable definition were included. Studies had to provide improvement in abdominal pain or global IBS symptoms as an outcome. Eligibility assessment and data extraction were performed by two independent researchers. Data were synthesised using relative risk (RR) of symptoms not improving for dichotomous data and standardised mean difference (SMD) for continuous data using random effects models. Results 19 RCTs (18 papers) in 1650 patients with IBS were identified. Trial quality was generally good, with nine reporting adequate methods of randomisation and six a method of concealment of allocation. There were 10 RCTs involving 918 patients providing outcomes as a dichotomous variable. Probiotics were statistically significantly better than placebo (RR of IBS not improving=0.71; 95% CI 0.57 to 0.88) with a number needed to treat (NNT)=4 (95% CI 3 to 12.5). There was significant heterogeneity (χ 2 =28.3, p=0.001, I 2 =68%) and possible funnel plot asymmetry. Fifteen trials assessing 1351 patients reported on improvement in IBS score as a continuous outcome (SMD=−0.34; 95% CI −0.60 to −0.07). There was statistically significant heterogeneity (χ 2 =67.04, p 2 =79%), but this was explained by one outlying trial. Conclusion Probiotics appear to be efficacious in IBS, but the magnitude of benefit and the most effective species and strain are uncertain.

Many of the symptoms characteristic of the functional gastrointestinal disorders (FGID) are consistent with dysfunction of the motor and/or sensory apparatus of the digestive tract. Those aspects of sensorimotor dysfunction most relevant to the FGID include alterations in: gut contractile activity; myoelectrical activity; tone and compliance; and transit, as well as an enhanced sensitivity to distension, in each region of the gastrointestinal tract. Assessment of these phenomena involves a number of techniques, some well established and others requiring further validation. Using such techniques, researchers have reported a wide range of alterations in sensory and in motor function in the FGID. Importantly, however, relationships between such dysfunction and symptoms have been relatively weak, and so the clinical relevance of the former remains unclear. Moreover, the proportions of patients in the various symptom subgroups who display dysfunction, and the extent and severity of their symptoms, require better characterization. On a positive note, progress is occurring on several fronts, especially in relation to functional dyspepsia and irritable bowel syndrome, and based on the data gathered to date, a number of areas where further advances are required can be highlighted. Keywords: motility; sensation; gastrointestinal tract; functional gut disorders; functional dyspepsia; irritable bowel syndrome; visceral hyperalgesia; Rome II

Objective The gut microbiota is an environmental regulator of fat storage and adiposity. Whether the microbiota represents a realistic therapeutic target for improving metabolic health is unclear. This study explored two antimicrobial strategies for their impact on metabolic abnormalities in murine diet-induced obesity: oral vancomycin and a bacteriocin-producing probiotic ( Lactobacillus salivarius UCC118 Bac + ). Design Male (7-week-old) C57BL/J6 mice (9–10/group) were fed a low-fat (lean) or a high-fat diet for 20 weeks with/without vancomycin by gavage at 2 mg/day, or with L salivarius UCC118Bac + or the bacteriocin-negative derivative L salivarius UCC118Bac − (each at a dose of 1×10 9 cfu/day by gavage). Compositional analysis of the microbiota was by 16S rDNA amplicon pyrosequencing. Results Analysis of the gut microbiota showed that vancomycin treatment led to significant reductions in the proportions of Firmicutes and Bacteroidetes and a dramatic increase in Proteobacteria , with no change in Actinobacteria. Vancomycin-treated high-fat-fed mice gained less weight over the intervention period despite similar caloric intake, and had lower fasting blood glucose, plasma TNFα and triglyceride levels compared with diet-induced obese controls. The bacteriocin-producing probiotic had no significant impact on the proportions of Firmicutes but resulted in a relative increase in Bacteroidetes and Proteobacteria and a decrease in Actinobacteria compared with the non-bacteriocin-producing control. No improvement in metabolic profiles was observed in probiotic-fed diet-induced obese mice. Conclusion Both vancomycin and the bacteriocin-producing probiotic altered the gut microbiota in diet-induced obese mice, but in distinct ways. Only vancomycin treatment resulted in an improvement in the metabolic abnormalities associated with obesity thereby establishing that while the gut microbiota is a realistic therapeutic target, the specificity of the antimicrobial agent employed is critical.

Gas content and transit appear to conspire with the motor and sensory responses of the gut to produce gas related symptoms, both in normal individuals and especially in patients with irritable bowel syndrome (IBS). In relation to gas in IBS, two questions need to be addressed: do IBS patients produce more gas and what are the relationships between intestinal gas and symptoms? The balance of evidence seems to indicate that distension is a real phenomenon in IBS and that such distension accurately reflects gas content. More problematic is extrapolation of the observations relating symptoms to gas transit and retention.

We recently read with great interest the article published by Barreau et al ( Gut 2008; 57 :582–90) who report, as one of their primary findings, mast cell hyperplasia and increased colonic rat mast cell protease II (RMCPII) activity following neonatal psychological stress. The authors also persuasively demonstrate a potential role for mast cell-derived nerve growth factor in contributing to increased colonic neural density in this model. In the study we describe here, using a related maternal separation procedure1 we also observed mast cell hyperplasia. However, this was restricted to the colonic submucosa and characterised by RMCPII immunoreactivity and predominantly blue or blue/red positive cells following Alcian blue/safranin staining, without an associated change in mucosal mast cell (MMC) number. Maternal separation was carried out using a protocol previously described by our group and known to induce a number of behavioural and gastrointestinal (GI) effects,1 and adult male animals, at least 11 weeks of age, were used in subsequent studies. To identify mast cells we used sheep anti-RMCP II (1:500; Moredun, Midlothian, UK) and Alcian blue (1% in 0.7 mol/l HCl)/safranin (0.5% in 0.125 mol/l HCl) staining. Analysis of colonic supernatants for RMCPII release was carried out using an enzyme-linked immunosorbent assay (ELISA; Moredun). Similarly to Barreau et al we identified extensive RMCPII positive staining along the crypt mucosa axis (non-separated (NS), 49.5 (SEM 3.7) mast cells/mm2, n = 10, maternally separated (MS), 53.1 (SEM 2.5) mast cells/mm2, n = 15, p>0.05) in rat colon; though …

While aspiration and feeding difficulties are well known challenges in the intensive care unit, their pathophysiology has been poorly understood. New information suggests that the critically ill are subject to profound alterations in motor and sensory function of the oesophagus, lower oesophageal sphincter, stomach, and duodenum which go some way to explaining their propensity to reflux and gastroparesis, with their attendant risks As medicine changes so should all aspects of medical care and knowledge; as more and more patients are subjected to surgical procedures of increasing complexity and risk and as survival rates from catastrophic illness rise, due to advances in surgery, anaesthesia, and intensive care, one would expect an associated growth in awareness of, and research into, the effects of critical illness on gut motor function. However, motor function and dysfunction, in this context, have received scant attention and have remained, for the most part, poorly understood. While a high prevalence of such phenomena as gastro-oesophageal reflux and gastroparesis are assumed, their true rates of occurrence have been scarcely documented. Similarly, while potential consequences of these entities, such as aspiration, oesophagitis, nosocomial pneumonia, feeding difficulties, and even gastric perforation are well known and, justifiably, feared, the effects of critical illness on oesophageal and gastric motor function have been little investigated. There are, it must be conceded, many reasons for this. Several factors, intrinsic to any intensive care (or therapy) unit (IC/TU) patient population, deter the clinician-scientist from embarking on the investigation of these subjects and confound the interpretation of any studies completed. First and foremost, this is, by definition, a heterogeneous population. Depending on the nature of a particular unit, it may include among its patients a wide range of ages as well as a diverse catalogue of precipitating illnesses and events. Among the latter, prior surgery, raised intracranial …

Introduction Linaclotide, a minimally absorbed guanylate cyclase-C agonist, was evaluated in a Phase 3 trial. To fulfil EMA submission requirements, the efficacy, safety and effects of withdrawal of linaclotide 290 μg in patients with IBS-C were assessed. Methods In a randomised, double-blind, placebo (PBO)-controlled trial, IBS-C patients (modified Rome II criteria), with an average of Results 800 patients (median age 44; female 90.5%) received linaclotide (n=405) or PBO (n=395). For the first co-primary parameter (≥30% reduction from baseline in mean abdominal pain or discomfort score for ≥6 of the 1st 12 wks with neither score worsening), 54.8% of linaclotide-treated patients and 41.8% of PBO-treated patients responded (p=0.0002). For the second co-primary parameter (patients “considerably relieved”/“completely relieved” on the weekly degree-of-relief of IBS symptoms question for ≥6 of the 1st 12 wks), 37.0% of linaclotide-treated patients and 18.5% of PBO-treated patients responded (p Conclusion In patients with IBS-C, linaclotide significantly improved all primary and secondary abdominal pain and bowel symptom parameters with no evidence of rebound on stopping treatment. Competing interests E M Quigley Consultant for: Ironwood Pharmaceuticals, A J Lembo Grant/Research Support from: Ironwood Pharmaceuticals, Consultant for: Ironwood Pharmaceuticals/Salix/Prometheus/Alkermes/Ardelyx/GSK/Theravance, Conflict with: Lecture fees from Ironwood Pharmaceuticals, C Diaz Employee of: Almirall, J Fortea Shareholder with: Almirall, Employee of: Almirall, M Falques Employee of: Almirall, S Shiff Employee of: Forest Research Institute, K Shi Employee of: Forest Research Institute, H A Schneier Employee of: Forest Research Institute, J M Johnston Employee of: Ironwood Pharmaceuticals.

Although transmission of hepatitis B virus (HBV) infection has long been recognised as a potential hazard of gastrointestinal endoscopy, there has been little evidence of direct patient-to-patient cross-infection after such procedures. We wish to report a case of type B viral hepatitis almost certainly acquired at endoscopy from an instrument sterilised in the conventional manner, but which had been used on the previous day on a patient with bleeding oesophageal varices who was incubating type B viral hepatitis.

In 1964 Samman and White described 13 patients with lymphoedema of the lower extremities associated with an unusual dystrophy of the finger and toe nails: this they termed the 'yellow-nail' syndrome. Affected nails were thickened, excessively curved along both axes, very slow growing and of yellowish-grey hue; cuticle and lunula were usually absent and onycholysis was frequently evident. Lower limb lymphangiography in most individuals revealed hypoplasia, or aplasia of the lymphatics, similar to that occurring in primary lymphoedema: other patients also developed pleural effusions of high protein content or ascites suggestive of a more generalised disorder of the lymphatic system. Here we describe a patient in whom the classical 'yellow-nail' syndrome was associated with intestinal and chylous ascites.