Houghton, L A

INTRODUCTION Gastroesophageal reflux is common in respiratory disease, but the interplay between gastrointestinal mechanisms that expose individuals to reflux and potentially aspiration, and lung mechanics and function remain incompletely understood. Our aim was to investigate this in patients with chronic obstructive pulmonary disease (COPD) and non-idiopathic pulmonary fibrosis (IPF) interstitial lung disease (non-IPF ILD), and compare with our published findings in IPF. METHODS Fifty-seven patients with COPD (aged: 34–75 years) and 64 with non-IPF ILD (22–75 years) who underwent high-resolution impedance manometry and 24-hour pH impedance together with pulmonary function assessment were compared with 35 IPF patients (51–84 years). RESULTS COPD patients were less likely to exhibit ineffective esophageal motility (IEM) and/or absent contractility ( P = 0.009; P = 0.028), and tended to exhibit esophagogastric junction outflow obstruction (EGJOO) and/or hypercontractility ( P = 0.09, P = 0.14) than IPF and non-IPF ILD patients. Notably, integrated relaxation pressure correlated with esophageal length index (ELI) ( P = 0.048) and inspiratory LESP ( P = 0.003), with latter 2 correlating with each other ( P < 0.001). EGJOO patients tended to have fewer proximal reflux events and reduced pulmonary function, with the latter inversely correlating with ELI ( P < 0.05). Non-IPF ILD patients were less likely to exhibit EGJOO than COPD patients ( P = 0.27), and less likely to exhibit IEM ( P = 0.07) than IPF patients. However, those with IEM or EGJOO exhibited greater proportions of reflux events reaching the proximal esophagus than those with normal motility ( P < 0.03), which in contrast to IPF, seemed not to associate with worse pulmonary function. DISCUSSION Associations between esophageal motility, and lung mechanics and function, and consequently reflux, are very disease-specific.

ABSTRACT Introduction Despite the emergence of drugs to treat irritable bowel syndrome (IBS), improving abdominal pain can still be challenging. α 2 δ ligands, such as gabapentin and pregabalin, are sometimes used off‐label to tackle this problem. However, evidence for efficacy is limited, and no large‐scale studies have been published. Aim To study the efficacy of the α 2 δ ligand PD‐217,014 in IBS. Methods This multi‐centre, double‐blind, randomised, placebo‐controlled, parallel group study randomised participants with Rome II‐defined IBS to 150 or 300 mg b.d. of PD‐217,014 or placebo b.d. for 4 weeks. The primary efficacy endpoint was responder, defined as having adequate relief of abdominal pain/discomfort for ≥ 50% of the active treatment period. Key secondary endpoints were change from baseline in abdominal pain, bloating, stool frequency/consistency, and global assessment of IBS symptoms. Results We randomised 330 participants [aged 19–73 years; 209 (65%) female] satisfying Rome II criteria, 322 (98%) were treated, and of whom 271 (84%) completed the study. In this study, 321 satisfied Rome IV criteria. Neither dose of PD‐217,014 improved the percentage of participants reporting adequate relief of abdominal pain/discomfort compared with placebo, either using the Rome II‐defined total cohort or Rome II and IV IBS bowel habit sub‐types. There were similar observations for secondary endpoints, and no association between abdominal pain or anxiety levels at baseline with participant improvement. PD‐217,014 was generally well tolerated. Conclusion This first large, dose‐ranging trial examining the efficacy of PD‐217,014 showed no significant efficacy in participants with IBS or bowel habit sub‐types, irrespective of their pain and anxiety levels.

AbstractBackgroundFor many patients with lung disease the only proven intervention to improve survival and quality of life is lung transplantation (LTx). Esophageal dysmotility and gastroesophageal reflux (GER) are common in patients with respiratory disease, and often associate with worse prognosis following LTx. Which, if any patients, should be excluded from LTx based on esophageal concerns remains unclear. Our aim was to understand the effect of LTx on esophageal motility diagnosis and examine how this and the other physiological and mechanical factors relate to GER and clearance of boluses swallowed.MethodsWe prospectively recruited 62 patients with restrictive (RLD) and obstructive (OLD) lung disease (aged 33–75 years; 42 men) who underwent high resolution impedance manometry and 24‐h pH‐impedance before and after LTx.Key ResultsRLD patients with normal motility were more likely to remain normal (p = 0.02), or if having abnormal motility to change to normal (p = 0.07) post‐LTx than OLD patients. Esophageal length (EL) was greater in OLD than RLD patients' pre‐LTx (p < 0.001), reducing only in OLD patients' post‐LTx (p = 0.02). Reduced EL post‐LTx associated with greater contractile reserve (r = 0.735; p = 0.01) and increased likelihood of motility normalization (p = 0.10). Clearance of reflux improved (p = 0.01) and associated with increased mean nocturnal baseline impedance (p < 0.001) in RLD but not OLD. Peristaltic breaks and thoraco‐abdominal pressure gradient impact both esophageal clearance of reflux and boluses swallowed (p < 0.05).Conclusions and InferencesRLD patients are more likely to show improvement in esophageal motility than OLD patients post‐LTx. However, the effect on GER is more difficult to predict and requires other GI, anatomical and pulmonary factors to be taken into consideration.

AbstractBackgroundThere are minimal epidemiological data comparing the burden of disorders of gut brain interaction (DGBI) in the UK with other countries. We compared the prevalence of DGBI in the UK with other countries that participated in the Rome Foundation Global Epidemiology Study (RFGES) online.MethodsParticipants from 26 countries completed the RFGES survey online including the Rome IV diagnostic questionnaire and an in‐depth supplemental questionnaire with questions about dietary habits. UK sociodemographic and prevalence data were compared with the other 25 countries pooled together.Key ResultsThe proportion of participants with at least one DGBI was lower in UK participants compared with in the other 25 countries (37.6% 95% CI 35.5%–39.7% vs. 41.2%; 95% CI 40.8%–41.6%,p = 0.001). The UK prevalence of 14 of 22 Rome IV DGBI, including irritable bowel syndrome (4.3%) and functional dyspepsia (6.8%), was similar to the other countries. Fecal incontinence, opioid‐induced constipation, chronic nausea and vomiting, and cannabinoid hyperemesis (p < 0.05) were more prevalent in the UK. Cyclic vomiting, functional constipation, unspecified functional bowel disorder, and proctalgia fugax (p < 0.05) were more prevalent in the other 25 countries. Diet in the UK population consisted of higher consumption of meat and milk (p < 0.001), and lower consumption of rice, fruit, eggs, tofu, pasta, vegetables/legumes, and fish (p < 0.001).Conclusions and InferencesThe prevalence and burden of DGBI is consistently high in the UK and in the rest of the world. Opioid prescribing, cultural, dietary, and lifestyle factors may contribute to differences in the prevalence of some DGBI between the UK and other countries.

LINKED CONTENTThis article is linked to Grover et al and Elwing & Sayuk papers. To view these articles, visit https://doi.org/10.1111/apt.16591 and https://doi.org/10.1111/apt.16603

SummaryBackgroundIrritable bowel syndrome (IBS) patients often experience meal‐associated symptoms. However, the underlying mechanisms are unclear.AimTo determine small intestinal mechanisms of lipid‐induced symptoms and rectal hypersensitivity in IBSMethodsWe recruited 26 IBS patients (12 IBS‐C, 14 IBS‐D) and 15 healthy volunteers (HV). In vivo permeability was assessed using saccharide excretion assay. Rectal sensitivity was assessed using a barostat before and after small bowel lipid infusion; symptoms were assessed throughout. Next, an extended upper endoscopy with probe‐based confocal laser endomicroscopy (pCLE) was performed with changes induced by lipids. Duodenal and jejunal mucosal biopsies were obtained for transcriptomics.ResultsFollowing lipid infusion, a higher proportion of HV than IBS patients reported no pain, no nausea, no fullness and no urgency (P < 0.05 for all). In a model adjusted for sex and anxiety, IBS‐C and IBS‐D patients had lower thresholds for first rectal sensation (P = 0.0007) and pain (P = 0.004) than HV. In vivo small intestinal permeability and mean pCLE scores were similar between IBS patients and HV. Post‐lipid, pCLE scores were higher than pre‐lipid but were not different between groups. Baseline duodenal transient receptor potential vanilloid (TRPV) 1 and 3 expression was increased in IBS‐D, and TRPV3 in IBS‐C. Duodenal TRPV1 expression correlated with abdominal pain (r = 0.51, FDR = 0.01), and inversely with first rectal sensation (r = −0.48, FDR = 0.01) and pain (r = −0.41, FDR = 0.02) thresholds.ConclusionLipid infusion elicits a greater symptom response in IBS patients than HV, which is associated with small intestinal expression of TRPV channels. TRPV‐mediated small intestinal chemosensitivity may mediate post‐meal symptoms in IBS.

LINKED CONTENTThis article is linked to Nelson et al and Vasant papers. To view these articles, visit https://doi.org/10.1111/apt.16437 and https://doi.org/10.1111/apt.16440

AbstractIrritable bowel syndrome (IBS) is a gut‐brain disorder in which symptoms are shaped by serotonin acting centrally and peripherally. The serotonin transporter gene SLC6A4 has been implicated in IBS pathophysiology, but the underlying genetic mechanisms remain unclear. We sequenced the alternative P2 promoter driving intestinal SLC6A4 expression and identified single nucleotide polymorphisms (SNPs) that were associated with IBS in a discovery sample. Identified SNPs built different haplotypes, and the tagging SNP rs2020938 seems to associate with constipation‐predominant IBS (IBS‐C) in females. rs2020938 validation was performed in 1978 additional IBS patients and 6,038 controls from eight countries. Meta‐analysis on data from 2,175 IBS patients and 6,128 controls confirmed the association with female IBS‐C. Expression analyses revealed that the P2 promoter drives SLC6A4 expression primarily in the small intestine. Gene reporter assays showed a functional impact of SNPs in the P2 region. In silico analysis of the polymorphic promoter indicated differential expression regulation. Further follow‐up revealed that the major allele of the tagging SNP rs2020938 correlates with differential SLC6A4 expression in the jejunum and with stool consistency, indicating functional relevance. Our data consolidate rs2020938 as a functional SNP associated with IBS‐C risk in females, underlining the relevance of SLC6A4 in IBS pathogenesis.

SummaryBackgroundAlthough bloating is a highly prevalent and troublesome symptom in irritable bowel syndrome with constipation (IBS‐C), treatment is empirical with no specific guidelines for its management.AimTo conduct a pairwise and network meta‐analysis, using a frequentist approach, of Food and Drug Administration‐licensed drugs for IBS‐C comparing their efficacy for abdominal bloating as a specific endpoint.MethodsWe searched the medical literature through December 2020 to identify randomised controlled trials (RCTs) in IBS‐C, with abdominal bloating reported as a dichotomous assessment. Efficacy of each drug was reported as a pooled relative risk (RR) with 95% confidence intervals (CIs) to summarise effect of each comparison tested. Treatments were ranked according to their P‐score.ResultsWe identified 13 eligible RCTs, containing 10 091 patients. Linaclotide 290 µg o.d., lubiprostone 8 µg b.d., tenapanor 50 mg b.d. and tegaserod 6 mg b.d. were all superior to placebo for abdominal bloating in patients with IBS‐C, in both pairwise and the network meta‐analyses. Linaclotide demonstrated the greatest improvement in abdominal bloating in both pairwise and network meta‐analysis (RR of failure to achieve an improvement in abdominal bloating = 0.78; 95% CI 0.74‐0.83, number needed to treat = 7, P‐score 0.97). Indirect comparison revealed no significant differences between individual drugs.ConclusionsWe found all licensed drugs for IBS‐C to be superior to placebo for abdominal bloating. Linaclotide appeared to be the most efficacious at relieving abdominal bloating. Further research is needed to assess long‐term efficacy of these agents and to better understand the precise mechanism of improving bloating.

Irritable bowel syndrome (IBS) remains one of the most common gastrointestinal disorders seen by clinicians in both primary and secondary care. Since publication of the last British Society of Gastroenterology (BSG) guideline in 2007, substantial advances have been made in understanding its complex pathophysiology, resulting in its re-classification as a disorder of gut-brain interaction, rather than a functional gastrointestinal disorder. Moreover, there has been a considerable amount of new evidence published concerning the diagnosis, investigation and management of IBS. The primary aim of this guideline, commissioned by the BSG, is to review and summarise the current evidence to inform and guide clinical practice, by providing a practical framework for evidence-based management of patients. One of the strengths of this guideline is that the recommendations for treatment are based on evidence derived from a comprehensive search of the medical literature, which was used to inform an update of a series of trial-based and network meta-analyses assessing the efficacy of dietary, pharmacological and psychological therapies in treating IBS. Specific recommendations have been made according to the Grading of Recommendations Assessment, Development and Evaluation system, summarising both the strength of the recommendations and the overall quality of evidence. Finally, this guideline identifies novel treatments that are in development, as well as highlighting areas of unmet need for future research.