Clonal Transitions and Phenotypic Evolution in Barrett's Esophagus.

BACKGROUND & AIMS: Barrett's esophagus (BE) is a risk factor for esophageal adenocarcinoma but our understanding of how it evolves is poorly understood. We investigated BE gland phenotype distribution, the clonal nature of phenotypic change, and how phenotypic diversity plays a role in progression. METHODS: Using immunohistochemistry and histology, we analyzed the distribution and the diversity of gland phenotype between and within biopsy specimens from patients with nondysplastic BE and those who had progressed to dysplasia or had developed postesophagectomy BE. Clonal relationships were determined by the presence of shared mutations between distinct gland types using laser capture microdissection sequencing of the mitochondrial genome. RESULTS: We identified 5 different gland phenotypes in a cohort of 51 nondysplastic patients where biopsy specimens were taken at the same anatomic site (1.0-2.0 cm superior to the gastroesophageal junction. Here, we observed the same number of glands with 1 and 2 phenotypes, but 3 phenotypes were rare. We showed a common ancestor between parietal cell-containing, mature gastric (oxyntocardiac) and goblet cell-containing, intestinal (specialized) gland phenotypes. Similarly, we have shown a clonal relationship between cardiac-type glands and specialized and mature intestinal glands. Using the Shannon diversity index as a marker of gland diversity, we observed significantly increased phenotypic diversity in patients with BE adjacent to dysplasia and predysplasia compared to nondysplastic BE and postesophagectomy BE, suggesting that diversity develops over time. CONCLUSIONS: We showed that the range of BE phenotypes represents an evolutionary process and that changes in gland diversity may play a role in progression. Furthermore, we showed a common ancestry between gastric and intestinal-type glands in BE.

Sensory Phenotype of the Oesophageal Mucosa in Gastro-Oesophageal Reflux Disease.

Gastroesophageal reflux disease (GORD) affects up to 20% of Western populations, yet sensory mechanisms underlying heartburn pathogenesis remain incompletely understood. While central mechanisms of heartburn perception have been established in earlier studies, recent studies have highlighted an important role of neurochemical, inflammatory, and cellular changes occurring in the oesophageal mucosa itself. The localization and neurochemical characterisation of sensory afferent nerve endings differ among GORD phenotypes, and could explain symptom heterogeneity among patients who are exposed to similar levels of reflux. Acid-induced stimulation of nociceptors on pain-sensing nerve endings can regulate afferent signal transmission. This review considers the role of peripheral mechanisms of sensitization in the amplification of oesophageal sensitivity in patients with GORD.

Changes in UK medical trainees' perceptions of workplace-based assessments across 10 years: results from two cross-sectional studies.

OBJECTIVES: Workplace-based assessments (WPBAs) have become embedded in the training and assessment of UK medical trainees since the onset of the 21st century. When first introduced WPBA required a significant adjustment in both trainees' and educators' training behaviour, and was met with scepticism in some quarters. In this study, we aimed to evaluate how trainees' perceptions of WPBAs have evolved over a 10-year period, as experience with them has increased. DESIGN: Two online questionnaires were constructed and distributed to UK trainees. The first was distributed in 2008, the second in 2018. Questions related to trainees' perception of WPBAs as a learning process and as a reflection of their competence. SETTING AND PARTICIPANTS: All UK medical trainees were eligible to respond. In 2008, 482 trainees from 96 hospitals completed the questionnaire. In 2018, 356 trainees from 103 hospitals completed the questionnaire. MAIN OUTCOME MEASURES: Data were analysed both quantitatively and qualitatively. A comparison between the numbers of each WPBA modality completed in 2008 and 2018 was assessed using chi-squared test. Comparisons of Likert scale values between 2008 and 2018 were assessed using unpaired t-test. Thematic analysis was carried out on free-text answers. RESULTS: The number of forms completed per participant increased significantly from 2008 to 2018. In 2008, forms were most commonly completed immediately after a learning observation (34%). In 2018, forms were most commonly completed between 1 week and 1 month after observation (58%). In 2018, significantly fewer WPBAs were followed by an educational/beneficial discussion in comparison to 2008 data. The most common free-text theme in the 2008 data set was 'supervisor issues' whereas in 2018 the most commonly noted theme was 'limited educational benefit'. CONCLUSIONS: Our study suggests trainees' perspectives of WPBAs have not changed in the 10 years since implementation. Trainees do not perceive WPBA as an accurate reflection of their competency but instead as a 'tick-box' bureaucratic exercise to enable career progression. Development of educator training and trainer and trainee job-planning is required to ensure that WPBAs are genuinely educational activities that offer an accurate reflection of trainees' medical competence.

Heartburn sensation in nonerosive reflux disease: pattern of superficial sensory nerves expressing TRPV1 and epithelial cells expressing ASIC3 receptors.

The underlying causes of heartburn, characteristic symptom of gastroesophageal reflux disease (GERD), remain incompletely understood. Superficial afferent innervation of the esophageal mucosa in nonerosive reflux disease (NERD) may drive nociceptive reflux perception, but its acid-sensing role has not yet been established. Transient receptor potential vanilloid subfamily member-1 (TRPV1), transient receptor potential melastatin 8 (TRPM8), and acid-sensing ion channel 3 (ASIC3) are regulators of sensory nerve activity and could be important reflux-sensing receptors within the esophageal mucosa. We characterized TRPV1, TRPM8, and ASIC3 expression in esophageal mucosa of patients with GERD. We studied 10 patients with NERD, 10 with erosive reflux disease (ERD), 7 with functional heartburn (FH), and 8 with Barrett's esophagus (BE). Biopsies obtained from the distal esophageal mucosa were costained with TRPV1, TRPM8, or ASIC3, and CGRP, CD45, or E-cadherin. RNA expression of TRPV1, TRPM8, and ASIC3 was assessed using qPCR. Patients with NERD had significantly increased expression of TRPV1 on superficial sensory nerves compared with ERD (P = 0.028) or BE (P = 0.017). Deep intrapapillary nerve endings did not express TRPV1 in all phenotypes studied. ASIC3 was exclusively expressed on epithelial cells most significantly in patients with NERD and ERD (P ≤0.0001). TRPM8 was expressed on submucosal CD45+ leukocytes. Superficial localization of TRPV1-immunoreactive nerves in NERD, and increased ASIC3 coexpression on epithelial cells in NERD and ERD, suggests a mechanism for heartburn sensation. Esophageal epithelial cells may play a sensory role in acid reflux perception and act interdependently with TRPV1-expressing mucosal nerves to augment hypersensitivity in patients with NERD, raising the enticing possibility of topical antagonists for these ion channels as a therapeutic option.NEW & NOTEWORTHY We demonstrate for the first time that increased pain perception in patients with nonerosive reflux disease likely results from expression of acid-sensitive channels on superficial mucosal afferents and esophageal epithelial cells, raising the potential for topical therapy.

Identification of Different Phenotypes of Esophageal Reflux Hypersensitivity and Implications for Treatment.

BACKGROUND & AIMS: Reflux hypersensitivity (RH), a functional esophageal disorder, is detected in 14%-20% of patients who present with typical esophageal symptoms. As many as 40% of patients with RH do not respond to treatment with pain modulators or proton pump inhibitors (PPIs); behavior disorders might contribute to lack of treatment efficacy. We aimed to assess the prevalence of behavioral disorders and their effects on typical reflux symptoms in patients with RH. METHODS: We performed a retrospective study of 542 patients with PPI-refractory esophageal symptoms (heartburn, regurgitation, or chest pain) or with symptoms that responded to PPI therapy, evaluated for anti-reflux surgery from January 2016 through August 2019 at a single center in London, United Kingdom. We collected data on symptoms, motility, and impedance-pH monitoring and assigned patients to categories of RH (n = 116), functional heartburn (n = 126), or non-erosive reflux disease (n = 300). RESULTS: Of the 116 patients with a diagnosis of RH, 59 had only hypersensitivity, whereas 57 patients (49.2%) had either excessive supragastric belching (SGB, 39.7%), based on 24-hour impedance-pH monitoring, or rumination (9.5%), based on postprandial manometry combined with impedance. The prevalence of SGB and rumination in patients with RH was significantly higher than in patients with functional heartburn (22%; P < .001). Patients with RH and rumination were significantly younger (P = .005) and had the largest number of non-acid reflux episodes (P = .023). In patients with RH with SGB, SGB episodes were associated with 40.6% of marked reflux symptoms (heartburn, regurgitation, or chest pain), based on impedance-pH monitoring. In patients with RH and rumination, 40% of reflux-related symptoms (mostly regurgitation) were due to possible rumination episodes. CONCLUSIONS: Almost half of patients with a diagnosis of RH have behavior disorders, including excessive SGB or rumination. Episodes of SGB or rumination are associated with typical reflux symptoms. Segregation of patients with diagnosis of RH into those with vs without behavioral disorders might have important therapeutic implications.

Esophageal Mucosa Innervation in Children With Nonerosive Reflux Disease.

INTRODUCTION: Esophageal mucosa innervation in adults with nonerosive reflux disease (NERD) is more superficial compared with healthy volunteers. We delineated the esophageal mucosal innervation in pediatric NERD and controls. METHODS: Distal and proximal pediatric esophageal biopsies were immunohistochemically stained with calcitonin gene-related peptide and transient receptor potential cation channel subfamily V member 1. RESULTS: Mucosal innervation was assessed in 18 controls (9M:9F, median age: 9 years) and 11 NERD patients (6M:5F, median age: 5 years). Calcitonin gene-related peptide positive nerve fibers were lying deep in the mucosa in both groups, P > 0.05 and did not coexpress transient receptor potential cation channel subfamily V member 1. DISCUSSION: The pediatric esophageal mucosa in NERD displays deep lying nerve fibers, in contrast to adults.

Esophageal afferent innervation and its role in gastro-esophageal reflux disease symptoms.

PURPOSE OF REVIEW: Despite the wide prevalence of gastro-esophageal reflux disease (GERD), the neurophysiological mechanisms underlying heartburn perception in the esophagus of patients with GERD remains incompletely understood. Recent studies have highlighted the potential influence sensory afferent nerves innervating the oesophageal epithelium may have on heartburn pathogenesis. The purpose of this review is to consider the current understanding of esophageal afferent neuronal innervation, including the nociceptive role of acid-sensing receptors expressed on these sensory nerves, in relation to pain perception in the esophagus of GERD patients. RECENT FINDINGS: Central and peripheral pathways of sensitization following noxious stimulation of nociceptive receptors expressed on afferent nerves can regulate the strength of sensory nerve activation in the esophagus, which can result in the amplification or suppression of afferent signal transmission. The localization and characterization of mucosal sensory afferent nerves vary between GERD phenotypes and may explain the heterogeneity of symptom perception in patients with apparently similar levels of reflux. SUMMARY: In this review, we discuss the relevance of afferent esophageal innervation in heartburn perception, with a particular focus on the pathways of reflux-induced activation of nociceptive nerves.

Rumination Syndrome in Children Presenting With Refractory Gastroesophageal Reflux Symptoms.

OBJECTIVES: Up to 40% of children presenting with reflux symptoms do not respond to standard medical interventions. In adults, 20% of patients presenting with Proton Pump Inhibitors refractory Gastro-Esophageal Reflux Disease (GERD) have rumination syndrome. The management of GERD and rumination differ significantly. Our study aimed to identify rumination syndrome amongst children presenting with persistent GERD symptoms based on a distinct pattern on impedance-pH monitoring. METHODS: The parameters of impedance-pH monitoring were compared between children with rumination syndrome (n = 12), diagnosed on high-resolution manometry impedance (HRM/Z), children with GERD (n = 18), children with an alternative diagnosis (non-GERD, n = 12) and children negative for rumination based on HRM/Z (n = 14). The parameters that distinguish the rumination group were identified and incorporated into a scoring system, which was blindly applied on a separate group of children with refractory GERD (n = 18) to define its sensitivity and specificity. RESULTS: Rumination syndrome presents in 44% of children with refractory GERD. Children with rumination syndrome present with a large number of proximal reflux episodes (>57.5 episodes/24 hours); a high frequency of nonacid reflux events in the postprandial period (>2/hour); and a highly positive symptom-reflux association analysis (SAP ≥ 95%). A score of ≥2 out of the 3 points distinguishes children with rumination syndrome with 75% sensitivity and 80% specificity. CONCLUSIONS: Children with rumination syndrome have a distinct pattern of impedance-pH monitoring and can be distinguished amongst children presenting with refractory GERD. Applying a simple scoring system during impedance-pH analysis could lead to early diagnosis of children with rumination syndrome.

Measurement of Salivary Pepsin to Detect Gastroesophageal Reflux Disease Is Not Ready for Clinical Application.

A noninvasive test for gastroesophageal reflux disease (GERD) is desirable for adults and children. Salivary pepsin measurement has been proposed as such a test.1-3 A previous study from our group demonstrated that a maximal salivary pepsin cutoff of >210 ng/mL using the PepTest device (RD Biomed, Hull, United Kingdom) had excellent specificity of 96% but modest sensitivity of 44% to diagnose GERD,4 leading to optimism about its potential use. In this study, we aimed to confirm the previously reported sensitivity and specificity in healthy volunteers and patients with heartburn, evaluate the association between a positive PepTest and response to proton pump inhibitor (PPI) therapy, assess if test-sensitivity can be improved for GERD when samples are taken over a 72-hour sampling period, and establish normal values of salivary pepsin in infants.

Persistent Postprandial Regurgitation vs Rumination in Patients With Refractory Gastroesophageal Reflux Disease Symptoms: Identification of a Distinct Rumination Pattern Using Ambulatory Impedance-pH Monitoring.

OBJECTIVES: Up to 20% of patients with refractory gastroesophageal reflux disease (GERD) might have postprandial rumination. The aim of this study was to distinguish persistent GERD-related postprandial regurgitation from rumination in patients with refractory GERD undergoing ambulatory multichannel intraluminal impedance-pH (MII-pH) monitoring. METHODS: We first characterized 24-hour and postprandial MII-pH patterns in 28 consecutive patients with confirmed rumination syndrome (positive clinical and high-resolution manometry/impedance). We compared such MII-pH patterns with those from 30 patients with typical GERD symptoms (10 nonerosive reflux disease, 10 hyperactive esophagus, and 10 functional heartburn) and 27 healthy controls. Using ROC curves, we selected the best MII-pH parameters to prepare an MII-pH rumination score. We prospectively tested the performance of the new MII-pH rumination score in 26 consecutive patients with refractory GERD (predominant regurgitation). RESULTS: Compared with GERD controls, patients with rumination were more often females, younger, and had significantly more postprandial early nonacid reflux episodes with high proximal extent. Postprandial reflux in ruminators had a distinct nadir pH profile over time (from nonacid to acid). Despite increased reflux events, baseline impedance in ruminators was similar to that in healthy subjects. Ruminators marked postprandial symptoms earlier and much more often than patients with GERD. An MII-pH-based rumination score (using postprandial nonacid reflux/hour and Symptom Index) diagnosed rumination in 46% of patients with refractory GERD and persistent regurgitation (sensitivity 91.7% and specificity 78.6%). DISCUSSION: Postprandial rumination is very common in refractory GERD with persistent regurgitation. A simple MII-pH score detects rumination in these patients with high sensitivity and specificity.

Superficial Esophageal Mucosal Afferent Nerves May Contribute to Reflux Hypersensitivity in Nonerosive Reflux Disease.

BACKGROUND & AIMS: Little is known about the causes of heartburn in patients with gastro-esophageal reflux disease. Visible epithelial damage is seldom associated with symptom severity, evidenced by the significant symptom burden in patients with nonerosive reflux disease (NERD) compared with patients with erosive reflux disease (ERD) or Barrett's esophagus (BE). We studied the distribution of mucosal nerve fibers in patients with NERD, ERD, and BE, and compared the results with those of healthy subjects. METHODS: We performed a prospective study of 13 patients with NERD, 11 patients with ERD, and 16 patients with BE undergoing endoscopic evaluation in the United Kingdom or Greece. Biopsies were obtained from the proximal and distal esophageal mucosa of patients with NERD, from the distal esophageal mucosa of patients with ERD, and the distal-most squamous epithelium of patients with BE. These were examined for the presence and location of nerve fibers that reacted with a labeled antibody against calcitonin gene-related peptide (CGRP), a marker of nociceptive sensory nerves. The results were compared with those from 10 healthy volunteers (controls). RESULTS: The distribution of CGRP-positive nerves did not differ significantly between the distal esophageal mucosa of controls (median, 25.5 cell layers to surface; interquartile range [IQR], 21.4-28.8) vs patients with ERD (median, 23 cell layers to surface; IQR, 16-27.5), or patients with BE (median, 21.5 cell layers to surface; IQR, 16.1-27.5). However, CGRP-positive nerves were significantly more superficial in mucosa from patients with NERD-both distal (median, 9.5 cell layers to surface; IQR, 1.5-13.3; P < .0001 vs ERD, BE, and controls) and proximal (median, 5.0 cell layers to surface; IQR, 2.5-9.3 vs median 10.4 cell layers to surface; IQR, 8.0-16.9; P = .0098 vs controls). CONCLUSIONS: Proximal and distal esophageal mucosa of patients with NERD have more superficial afferent nerves compared with controls or patients with ERD or BE. Acid hypersensitivity in patients with NERD might be partially explained by the increased proximity of their afferent nerves to the esophageal lumen, and therefore greater exposure to noxious substances in refluxate.

A novel murine model of esophageal nonerosive reflux disease: from inflammation to impairment in mucosal integrity.

Nonerosive reflux disease (NERD) is a highly prevalent phenotype of the gastroesophageal reflux disease. In this study, we developed a novel murine model of NERD in mice with microscopic inflammation and impairment in the epithelial esophageal barrier. Female Swiss mice were subjected to the following surgical procedure: the transitional region between the forestomach and the glandular portion of the stomach was ligated, and a nontoxic ring was placed around the duodenum near the pylorus. The control group underwent sham surgery. The animals were euthanized at 1, 3, 7, and 14 days after surgery. Survival and body weight were monitored daily. Esophageal wet weight, macroscopic lesion, histopathological alterations, myeloperoxidase (MPO) activity, cytokine levels, transepithelial electrical resistance (TEER), and mucosal permeability were evaluated. The survival rate was 78% at 14 days, with mild loss in body weight. Surgery did not induce erosive esophagitis but instead induced microscopic inflammation and increased esophageal wet weight, IL-6, keratinocyte-derived cytokine (KC) levels, and MPO activity with maximal peak between 3 and 7 days and resolution at 14 days postsurgery. Epithelial esophageal barrier was evaluated in operated mice at 7 and 14 days postsurgery; a decrease in TEER and increase in the esophageal epithelial permeability were observed compared with the sham-operated group. In addition, the inhibition of acid secretion with omeprazole significantly prevented the esophageal inflammation and impairment of barrier function at 7 days postsurgery. Thus we established a novel experimental model of NERD in mice, which can contribute to understanding the pathophysiological events associated with NERD.NEW & NOTEWORTHY In this study, we standardized an experimental model of nonerosive reflux disease (NERD) in mice. This model involves an acute inflammatory response followed by impaired esophageal mucosal integrity, even in the absence of inflammation. Thus this model can serve for evaluation of pathophysiological aspects of NERD and open new perspectives for therapeutic strategies for patients with this disorder.

Distinct afferent innervation patterns within the human proximal and distal esophageal mucosa.

Little is known about the mucosal phenotype of the proximal human esophagus. There is evidence to suggest that the proximal esophagus is more sensitive to chemical and mechanical stimulation compared with the distal. This may have physiological relevance (e.g., in prevention of aspiration of gastroesophageal refluxate), but also pathological relevance (e.g., in reflux perception or dysphagia). Reasons for this increased sensitivity are unclear but may include impairment in mucosal barrier integrity or changes in sensory innervation. We assessed mucosal barrier integrity and afferent nerve distribution in the proximal and distal esophagus of healthy human volunteers. In 10 healthy volunteers baseline proximal and distal esophageal impedance was measured in vivo. Esophageal mucosal biopsies from the distal and proximal esophagus were taken, and baseline transepithelial electrical resistance (TER) was measured in Ussing chambers. Biopsies were examined immunohistochemically for presence and location of calcitonin gene-related peptide (CGRP)-immunoreactive nerve fibers. In a further four healthy volunteers we investigated for colocalization of CGRP and protein gene product (PGP) 9.5 immunoreactivity in nerve fibers. Baseline impedance was higher in the proximal than in the distal esophagus [2,936 Ω (SD578) vs. 2,229 Ω (SD821); P = 0.03], however, baseline TER was not significantly different between them. Mucosal CGRP-immunoreactive nerves were found in the epithelium of both proximal and distal esophagus, but were located more superficially in the proximal mucosa compared with the distal [11.5 (SD7) vs. 21.7 (SD5) cell layers from lumen, P = 0.002] 19% of proximal, and 10% of distal mucosal PGP-immunoreactive fibers colocalized with CGRP. PGP-immunoreactive fibers were also significantly closer to the luminal surface in the proximal compared with the distal esophagus (P < 0.001). We conclude that mucosal barrier integrity is similar in proximal and distal esophagus, but proximal mucosal afferent nerves are in a more superficial location. The enhanced sensitivity to reflux-evoked symptoms of the proximal esophagus most likely has an anatomical basis.

Esophageal mucosal integrity in nonerosive reflux disease.

Gastroesophageal reflux disease, especially when refractory to standard therapy, remains a significant clinical problem. Although symptom pathogenesis in erosive reflux disease is relatively easy to understand, it is less clear how exposure of the macroscopically normal mucosa in nonerosive reflux disease (NERD) is able to cause heartburn. Over recent years it has become apparent that there may be microscopic and functional defects in the esophageal epithelial barrier in NERD, a so-called impairment of esophageal mucosal integrity. This can be expressed in morphologic or in functional terms. Morphologically the epithelium in NERD displays dilated intercellular spaces, which may represent a failed epithelial barrier, probably due to disruption of cell apical junctional complexes. Functionally, the mucosa in NERD displays more permeability to ions and small molecules than that of control subjects. Both morphologic and functional changes can be induced by exposure to refluxate-like solutions in vitro and in vivo. This article summarizes the evidence for impairment of esophageal mucosal integrity, and discusses its possible role in disease pathogenesis.

In vivo evaluation of acid-induced changes in oesophageal mucosa integrity and sensitivity in non-erosive reflux disease.

OBJECTIVE: Patients with non-erosive reflux disease (NERD) have impaired oesophageal mucosal integrity (dilated intercellular spaces). Oesophageal mucosal integrity reflects the balance between repeated reflux damage and mucosal recovery. The relationship between mucosal integrity and acid sensitivity is unclear. Oesophageal impedance may be used for in vivo mucosal integrity measurement. We studied acid-induced changes in oesophageal mucosal integrity and acid perception in patients with heartburn. DESIGN: 50 patients with heartburn whithout oesophagitis underwent impedance monitoring before, during and after 10 min oesophageal perfusion with neutral (pH 6.5) and acid solutions (pH 1). Symptoms and impedance were recorded during perfusion. Impedance recovery was assessed for 2 h post-perfusion in ambulatory conditions followed by 24-h impedance-pH study. RESULTS: Reflux monitoring discriminated 20 NERD and 30 functional heartburn (FH) patients. Neutral perfusion caused impedance fall that recovered within 10 min. Acid perfusion caused impedance fall with slow recovery: 6.5 Ω/min (IQR 3.3-12.0 Ω/min). Patients with slow recovery (< 25th percentile) had lower baseline impedance (1273 Ω ± 208 Ω vs. 3220 Ω ± 275 Ω ±, p < 0.01) and more frequent acid sensitivity (10/12 vs. 4/12, p = 0.04) than those with fast (> 75th percentile) recovery. Patients with NERD had lower baseline impedance (1669 ± 182 Ω vs. 2384 ± 211 Ω, p = 0.02) and slower impedance recovery (6.0 ± 0.9 Ω/min vs. 10.7 ± 1.6 Ω/min, p = 0.03) than patients with FH. CONCLUSION: Impaired mucosal integrity might be the consequence of repeated reflux episodes with slow recovery. Mucosal integrity, recovery capacity and symptom perception are linked. Low basal impedance and slow recovery after acid challenge are associated with increased acid sensitivity.

Superficial oesophageal mucosal innervation may contribute to severity of symptoms in oesophageal motility disorders.

BACKGROUND: Mechanisms underlying perception of dysphagia and chest pain have not been completely elucidated, although oesophageal mucosal afferent nerves might play an important role. AIMS: To evaluate the relationship between oesophageal mucosal afferent nerves and the severity of dysphagia and chest pain in oesophageal motility disorders. METHODS: We prospectively recruited patients with oesophageal motility disorders having dysphagia and/or chest pain from whom oesophageal biopsies were obtained. High-resolution manometry classified patients into disorders of oesophagogastric junction (OGJ) outflow and disorders of peristalsis. Symptom severity was assessed using validated questionnaires including Brief Oesophageal Dysphagia Questionnaire (BEDQ). Immunohistochemistry was performed on oesophageal biopsies to evaluate the location of calcitonin gene-related peptide (CGRP)-immunoreactive mucosal afferent nerves. Findings were compared to existing data from 10 asymptomatic healthy volunteers. RESULTS: Of 79 patients, 61 patients had disorders of OGJ outflow and 18 had disorders of peristalsis. CGRP-immunoreactive mucosal nerves were more superficially located in the mucosa of patients with oesophageal motility disorders compared to healthy volunteers. Within disorders of OGJ outflow, the location of CGRP-immunoreactive nerves negatively correlated with BEDQ score both in the proximal (ρ = -0.567, p < 0.001) and distal oesophagus (ρ = -0.396, p = 0.003). In the proximal oesophagus, strong chest pain was associated with more superficially located mucosal nerves than weak chest pain (p = 0.04). Multivariate analysis showed superficial nerves in the proximal oesophagus was independently associated with severe dysphagia in disorders of OGJ outflow (p = 0.008). CONCLUSIONS: Superficial location of mucosal nerves in the proximal oesophagus might contribute to symptoms, especially severe dysphagia, in disorders of OGJ outflow.

Investigating iRHOM2-Associated Transcriptional Changes in Tylosis With Esophageal Cancer.

Background and Aims: Survival rates for esophageal squamous cell carcinoma (ESCC) are extremely low due to the late diagnosis of most cases. An understanding of the early molecular processes that lead to ESCC may facilitate opportunities for early diagnosis; however, these remain poorly defined. Tylosis with esophageal cancer (TOC) is a rare syndrome associated with a high lifetime risk of ESCC and germline mutations in RHBDF2, encoding iRhom2. Using TOC as a model of ESCC predisposition, this study aimed to identify early-stage transcriptional changes in ESCC development. Methods: Esophageal biopsies were obtained from control and TOC individuals, the latter undergoing surveillance endoscopy, and adjacent diagnostic biopsies were graded as having no dysplasia or malignancy. Bulk RNA-Seq was performed, and findings were compared with sporadic ESCC vs normal RNA-Seq datasets. Results: Multiple transcriptional changes were identified in TOC samples, relative to controls, and many were detected in ESCC. Accordingly, pathway analyses predicted an enrichment of cancer-associated processes linked to cellular proliferation and metastasis, and several transcription factors were predicted to be associated with TOC and ESCC, including negative enrichment of GRHL2. Subsequently, a filtering strategy revealed 22 genes that were significantly dysregulated in both TOC and ESCC. Moreover, Keratin 17, which was upregulated in TOC and ESCC, was also found to be overexpressed at the protein level in 'normal' TOC esophagus tissue. Conclusion: Transcriptional changes occur in TOC esophagus prior to the onset of dysplasia, many of which are associated with ESCC. These findings support the utility of TOC to help reveal the early molecular processes that lead to sporadic ESCC.

Increased prandial air swallowing and postprandial gas-liquid reflux among patients refractory to proton pump inhibitor therapy.

BACKGROUND & AIMS: Many patients with gastroesophageal reflux disease (GERD) have persistent reflux despite treatment with proton pump inhibitors (PPIs). Mixed gas-liquid reflux events are more likely to be perceived as symptomatic. We used esophageal impedance monitoring to investigate whether esophageal gas is processed differently among patients with GERD who do and do not respond to PPI therapy. METHODS: We performed a prospective study of 44 patients with typical reflux symptoms with high levels of esophageal acid exposure during a 24-hour period; 18 patients were fully responsive, and 26 did not respond to PPI therapy. Twenty-four-hour pH impedance recordings were analyzed for fasting and prandial air swallows and reflux characteristics, including the presence of gas in the refluxate. RESULTS: PPI-refractory patients had a higher number (83.1 ± 12.7 vs 47.8 ± 7.3, P < .05) and rate (10.5 ± 1.4 vs 5.9 ± 0.8/10 minutes, P < .05) of prandial air swallows than patients who responded to PPI therapy; they also had a higher number (25.5 ± 4.0 vs 16.8 ± 3.3, P < .05) and proportion (70% ± 0.03% vs 54% ± 0.06%, P < .05) of postprandial, mixed gas-liquid reflux. Symptoms of PPI-refractory patients were more often preceded by mixed gas-liquid reflux events than those of PPI responders. Fasting air swallowing and other reflux characteristics did not differ between patients who did and did not respond to PPIs. CONCLUSIONS: Some patients with GERD who do not respond to PPI therapy swallow more air at mealtime than those who respond to PPIs and also have more reflux episodes that contain gas. These factors, combined with mucosal sensitization by previous exposure to acid, could affect perception of symptoms. These patients, who can be identified on standard 24-hour pH impedance monitoring, might be given behavioral therapy to reduce mealtime air swallowing.

Assessment and protection of esophageal mucosal integrity in patients with heartburn without esophagitis.

OBJECTIVES: Intact esophageal mucosal integrity is essential to prevent symptoms during gastroesophageal reflux events. Approximately 70% of patients with heartburn have macroscopically normal esophageal mucosa. In patients with heartburn, persistent functional impairment of esophageal mucosal barrier integrity may underlie remaining symptoms. Topical protection of a functionally vulnerable mucosa may be an attractive therapeutic strategy. We aimed to evaluate esophageal mucosal functional integrity in patients with heartburn without esophagitis, and test the feasibility of an alginate-based topical mucosal protection. METHODS: Three distal esophageal biopsies were obtained from 22 patients with heartburn symptoms, and 22 control subjects. In mini-Ussing chambers, the change in transepithelial electrical resistance (TER) of biopsies when exposed to neutral, weakly acidic, and acidic solutions was measured. The experiment was repeated in a further 10 patients after pretreatment of biopsies with sodium alginate, viscous control, or liquid control "protectant" solutions. RESULTS: Biopsy exposure to neutral solution caused no change in TER. Exposure to weakly acidic and acidic solutions caused a greater reduction in TER in patients than in controls (weakly acid -7.2% (95% confidence interval (CI) -9.9 to -4.5) vs. 3.2% (-2.2 to 8.6), P<0.05; acidic -22.8% (-31.4 to 14.1) vs. -9.4% (-17.2 to -1.6), P<0.01). Topical pretreatment with alginate but not with control solutions prevented the acid-induced decrease in TER (-1% (-5.9 to 3.9) vs. -13.5 (-24.1 to -3.0) vs. -13.2 (-21.7 to -4.8), P<0.05). CONCLUSIONS: Esophageal mucosa in patients with heartburn without esophagitis shows distinct vulnerability to acid and weakly acidic exposures. Experiments in vitro suggest that such vulnerable mucosa may be protected by application of an alginate-containing topical solution.

Management of gastro-oesophageal reflux disease symptoms that do not respond to proton pump inhibitors.

PURPOSE OF REVIEW: Treatment-refractory gastro-oesophageal reflux disease (GERD) remains a significant problem in the gastroenterology clinic. In recent years, several studies have investigated the assessment and treatment of refractory GERD. RECENT FINDINGS: Patients presenting with 'refractory GERD' in fact represent a quite heterogeneous group consisting of those with ongoing reflux-related symptoms and those with reflux-unrelated problems such as functional heartburn, dyspepsia or even eosinophilic oesophagitis. The greatest symptom indicators of persistent true reflux are retrosternal burning and acid taste in the mouth alone. Combined pH-impedance studies allow detection of reflux regardless of pH, and weakly acidic reflux has been suggested as a mechanism of residual symptoms in some patients. The use of reflux-symptom association calculations may help to determine the symptom causation, but refinement and outcome studies are needed. New treatments of refractory GERD have been disappointing. Surgery remains an option in very carefully selected patients, but again better outcome studies are required. SUMMARY: Careful history and investigation is required in the assessment of the proton pump inhibitor (PPI)-refractory patient. Care to exclude alternative diagnoses is needed, and to phenotype those with reflux-related symptoms. Optimization of PPI therapy may help, as may surgery in selected patients.