Hypoxia-inducible factor-2α plays a role in mediating oesophagitis in GORD

Hypoxia-inducible factor-1α mediates reflux-induced epithelial-mesenchymal plasticity in Barrett's oesophagus patients

INTRODUCTION

Epithelial-mesenchymal plasticity (EMP), the process through which epithelial cells acquire mesenchymal features, is needed for wound repair but also might contribute to cancer initiation. Earlier, in vitro studies showed that Barrett's cells exposed to acidic bile salt solutions (ABS) develop EMP. Now, we have (1) induced reflux oesophagitis in Barrett's oesophagus (BO) patients by stopping proton pump inhibitors (PPIs), (2) assessed their biopsies for EMP and (3) explored molecular pathways underlying reflux-induced EMP in BO cells and spheroids.

METHODS

15 BO patients had endoscopy with biopsies of Barrett's metaplasia while on PPIs, and 1 and 2 weeks after stopping PPIs; RNA-seq data were assessed for enrichments in hypoxia-inducible factors (HIFs), angiogenesis and EMP pathways. In BO biopsies, cell lines and spheroids, EMP features (motility) and markers (vascular endothelial growth factor (VEGF), ZEB1, miR-200a&b) were evaluated by morphology, migration assays, immunostaining and qPCR; HIF-1α was knocked down with siRNA or shRNA.

RESULTS

At 1 and/or 2 weeks off PPIs, BO biopsies exhibited EMP features and markers, with significant enrichment for HIF-1α, angiogenesis and EMP pathways. In BO cells, ABS induced HIF-1α activation, which decreased miR-200a&b while increasing VEGF, ZEB1 and motility; HIF-1α knockdown blocked these effects. After ABS treatment, BO spheroids exhibited migratory protrusions showing nuclear HIF-1α, increased VEGF and decreased miR-200a&b.

CONCLUSIONS

In BO patients, reflux oesophagitis induces EMP changes associated with increased HIF-1α signalling in Barrett's metaplasia. In Barrett's cells, ABS trigger EMP via HIF-1α signalling. Thus, HIF-1α appears to play a key role in mediating reflux-induced EMP that might contribute to cancer in BO.

TRIAL REGISTRATION NUMBER

NCT02579460.

Mucosal neuroimmune mechanisms in gastro-oesophageal reflux disease (GORD) pathogenesis

Gastro-oesophageal reflux disease (GORD) is a chronic condition characterised by visceral pain in the distal oesophagus. The current first-line treatment for GORD is proton pump inhibitors (PPIs), however, PPIs are ineffective in a large cohort of patients and long-term use may have adverse effects. Emerging evidence suggests that nerve fibre number and location are likely to play interrelated roles in nociception in the oesophagus of GORD patients. Simultaneously, alterations in cells of the oesophageal mucosa, namely epithelial cells, mast cells, dendritic cells, and T lymphocytes, have been a focus of GORD research for several years. The oesophagus of GORD patients exhibits both macro- and micro-inflammation as a response to chronic acidic reflux at the epithelium. In other conditions of the GI tract, such as IBS and IBD, well-characterised bidirectional processes between immune cells and mucosal nerve fibres contribute to pathogenesis and symptom generation. Sensory alterations in these conditions such as nerve fibre outgrowth and hypersensitivity can be driven by inflammatory processes, which promote visceral pain signalling. This review will examine what is currently known of the molecular pathways linking inflammation and sensory perception leading to the development of GORD symptoms and explore potentially relevant mechanisms in other GI regions which may indicate new areas in GORD research.

Immunoglobulin G-mediated food intolerance and metabolic syndrome influence the occurrence of reflux esophagitis in Helicobacter pylori-infected patients

BACKGROUND

Reflux esophagitis has an increasing prevalence and complex and diverse symptoms. Identifying its risk factors is crucial to understanding the etiology, prevention, and management of the disease. The occurrence of reflux esophagitis may be associated with food reactions, Helicobacter pylori (H. pylori) infection, and metabolic syndromes.

AIM

To investigate the risk factors for reflux esophagitis and analyze the effects of immunoglobulin (Ig) G-mediated food intolerance, H. pylori infection, and metabolic syndrome on reflux esophagitis.

METHODS

Outpatients attending the Second Medical Center of the PLA General Hospital between 2017 and 2021 were retrospectively enrolled. The patients' basic information, test results, gastroscopy results, H. pylori test results, and IgG-mediated food intolerance results were collected. Multivariate logistic regression analysis was used to analyze risk factors for reflux esophagitis. Statistical mediation analysis was used to evaluate the effects of IgG-mediated food intolerance and metabolic syndrome on H. pylori infection affecting reflux esophagitis.

RESULTS

A total of 7954 outpatients were included; the prevalence of reflux esophagitis, IgG-mediated food intolerance, H. pylori infection, and metabolic syndrome were 20.84%, 61.77%, 35.91%, and 60.15%, respectively. Multivariate analysis showed that the independent risk factors for reflux esophagitis included IgG-mediated food intolerance (OR = 1.688, 95%CI: 1.497-1.903, P < 0.00001) and metabolic syndrome (OR = 1.165, 95%CI: 1.030-1.317, P = 0.01484), and the independent protective factor for reflux esophagitis was H. pylori infection (OR = 0.400, 95%CI: 0.351-0.456, P < 0.00001). IgG-mediated food intolerance had a partially positive mediating effect on H. pylori infection as it was associated with reduced occurrence of reflux esophagitis (P = 0.0200). Metabolic syndrome had a partially negative mediating effect on H. pylori infection and reduced the occurrence of reflux esophagitis (P = 0.0220).

CONCLUSION

Patients with IgG-mediated food intolerance and metabolic syndrome were at higher risk of developing reflux esophagitis, while patients with H. pylori infection were at lower risk. IgG-mediated food intolerance reduced the risk of reflux esophagitis pathogenesis in patients with H. pylori infection; however, metabolic syndrome increased the risk of patients with H. pylori infection developing reflux esophagitis.

Identification of novel immune cell signature in gastroesophageal reflux disease: altered mucosal mast cells and dendritic cell profile

Introduction

Heartburn pathogenesis in GERD remains incompletely understood. We aimed to identify differences in the immune cell signature and sensory mucosal markers between reflux phenotypes and healthy asymptomatic subjects.

Methods

Thirty-seven patients with heartburn symptoms were phenotyped endoscopically and with objective reflux studies into erosive reflux disease (ERD) (N=10), nonerosive reflux disease (NERD) (N=9), functional heartburn (FH) (N=9), and Barrett's esophagus (BO) (N=9). Bulk mRNA-sequencing(RNA-seq) was conducted on RNA extracted from endoscopic biopsies, and immune cell deconvolution analysis was performed using CIBERSORT. RNA-seq findings were validated by immunofluorescent staining for CD1a, nerve growth factor (NGF), and mast cell tryptase in corresponding patient biopsies.

Results

Transcriptomic analysis detected higher mast cell abundance in BO, ERD, and NERD compared to healthy controls (p<0.05), with decreased dendritic cell infiltration in BO, ERD, and NERD patients compared to healthy controls and FH patients. CD1a-positive dendritic cell infiltration was significantly higher in the healthy esophageal mucosa at protein level compared to BO (p=0.0005), ERD (p=0.0004), and FH patients (p=0.0096). Moreover, NGF co-expression on mast cells in GERD patients was significantly higher than in healthy controls (p=0.0094).

Discussion

The mucosa in patients with GERD had a significant increase in NGF expression on mast cells, suggesting an upregulation of signalling for neuronal sprouting in GERD. Moreover, decreased dendritic cell abundance in GERD esophageal mucosa may play a role in reduced oral tolerance and development of subsequent immune responses which may participate in esophageal sensitivity.

Translating Molecular Biology Discoveries to Develop Targeted Cancer Interception in Barrett's Esophagus

Esophageal adenocarcinoma (EAC) is a rapidly increasing lethal tumor. It commonly arises from a metaplastic segment known as Barrett's esophagus (BE), which delineates the at-risk population. Ample research has elucidated the pathogenesis of BE and its progression from metaplasia to invasive carcinoma; and multiple molecular pathways have been implicated in this process, presenting several points of cancer interception. Here, we explore the mechanisms of action of various agents, including proton pump inhibitors, non-steroidal anti-inflammatory drugs, metformin, and statins, and explain their roles in cancer interception. Data from the recent AspECT trial are discussed to determine how viable a multipronged approach to cancer chemoprevention would be. Further, novel concepts, such as the repurposing of chemotherapeutic drugs like dasatinib and the prevention of post-ablation BE recurrence using itraconazole, are discussed.

Signaling Pathways in the Pathogenesis of Barrett's Esophagus and Esophageal Adenocarcinoma

Barrett's esophagus (BE) is a premalignant lesion that can develop into esophageal adenocarcinoma (EAC). The development of Barrett's esophagus is caused by biliary reflux, which causes extensive mutagenesis in the stem cells of the epithelium in the distal esophagus and gastro-esophageal junction. Other possible cellular origins of BE include the stem cells of the mucosal esophageal glands and their ducts, the stem cells of the stomach, residual embryonic cells and circulating bone marrow stem cells. The classical concept of healing a caustic lesion has been replaced by the concept of a cytokine storm, which forms an inflammatory microenvironment eliciting a phenotypic shift toward intestinal metaplasia of the distal esophagus. This review describes the roles of the NOTCH, hedgehog, NF-κB and IL6/STAT3 molecular pathways in the pathogenesis of BE and EAC.

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.

Updated perspective of EPAS1 and the role in pulmonary hypertension

Pulmonary hypertension (PH) is a group of syndromes characterized by irreversible vascular remodeling and persistent elevation of pulmonary vascular resistance and pressure, leading to ultimately right heart failure and even death. Current therapeutic strategies mainly focus on symptoms alleviation by stimulating pulmonary vessel dilation. Unfortunately, the mechanism and interventional management of vascular remodeling are still yet unrevealed. Hypoxia plays a central role in the pathogenesis of PH and numerous studies have shown the relationship between PH and hypoxia-inducible factors family. EPAS1, known as hypoxia-inducible factor-2 alpha (HIF-2α), functions as a transcription factor participating in various cellular pathways. However, the detailed mechanism of EPAS1 has not been fully and systematically described. This article exhibited a comprehensive summary of EPAS1 including the molecular structure, biological function and regulatory network in PH and other relevant cardiovascular diseases, and furthermore, provided theoretical reference for the potential novel target for future PH intervention.

Alginates for Protection Against Pepsin-Acid Induced Aerodigestive Epithelial Barrier Disruption

OBJECTIVE

Gastroesophageal reflux disease (GERD) and laryngopharyngeal reflux (LPR) are chronic conditions caused by backflow of gastric and duodenal contents into the esophagus and proximal aerodigestive tract, respectively. Mucosal barrier dysfunction resultant from the synergistic actions of chemical injury and the mucosal inflammatory response during reflux contributes to symptom perception. Alginates effectively treat symptoms of mild to moderate GERD and have recently shown benefit for LPR. In addition to forming a "raft" over gastric contents to reduce acidic reflux episodes, alginates have been found to bind the esophageal mucosa thereby preserving functional barrier integrity measured by transepithelial electrical resistance. The aim of this study was to further examine the topical protective capacity of alginate-based Gaviscon Advance (GA) and Double Action (GDA) against pepsin-acid mediated aerodigestive epithelial barrier dysfunction in vitro.

STUDY DESIGN

Translational.

METHODS

Immortalized human esophageal and vocal cord epithelial cells cultured in transwells were pretreated with liquid formula GA, GDA, matched viscous placebo solution, or saline (control), then treated for 1 h with saline, acid (pH 3-6) or pepsin (0.1-1 mg/ml) at pH 3-6. Endpoint measure was taken of horseradish peroxidase (HRP) allowed to diffuse across monolayers for 2 h.

RESULTS

Pepsin (0.1-1 mg/ml) at pH 3-6 increased HRP flux through cultures pretreated with saline or placebo (p < 0.05); acid alone did not. GA and GDA prevented barrier dysfunction.

CONCLUSIONS

GA and GDA preserved epithelial barrier function during pepsin-acid insult better than placebo suggesting that protection was due to alginate. These data support topical protection as a therapeutic approach to GERD and LPR. Laryngoscope, 132:2327-2334, 2022.

Network pharmacology-based prediction and verification of the active ingredients and potential targets of Huagan Decoction for reflux esophagitis

ETHNOPHARMACOLOGICAL RELEVANCE

Huagan Decoction (HGD), a famous traditional Chinese medicine (TCM) formula, has been widely used in the treatment of reflux esophagitis (RE). However, its effective compounds, potential targets and molecular mechanism remain unclear.

AIM OF THE STUDY

To investigate effective compounds, potential targets and molecular mechanism of HGD against RE by using network pharmacology combined with in vitro validation, with the aims of observing the action of HGD and exploring new therapeutic strategies for RE treatment.

MATERIALS AND METHODS

Effective compounds and potential targets of HGD, as well as related genes of RE, were collected from public databases. Pharmacological clustering and Gene Ontology (GO) enrichment analysis were applied to find targets that involving in the anti-inflammatory module. The pathways were drawn using Cytoscape 3.8.0. Important ingredients, potential targets, and signaling pathways were determined through the construction of protein-protein interaction (PPI), GO and Kyoto Encyclopedia of Genes and Genomes (KEGG). Subsequently, cell experiments were carried out.

RESULTS

A total of 54 active ingredients and 240 RE-related gene targets of HGD were identified. The active compound-target network was visualized and pharmacological clustering further sorted 53 proteins that involve in the regulation of inflammatory responses. GO analysis confirmed the classification was statistically significant. Analysis of compound-target network revealed that quercetin and geniposide may be key ingredients for the anti-inflammatory effect of HGD against RE. The potential targets regulated by HGD are IL-6, IL-1β, PTGS2, AKT1, TNF-α, MAPK1, IL-8, IL-10, CCL2 and MAPK3. In vitro experiment showed that quercetin and geniposide could inhibit the inflammatory response of HET-1A cells through p38MAPK/NF-κB signaling pathway, which was consistent with the prediction by the network pharmacology approach.

CONCLUSIONS

Geniposide and quercetin could be effective therapeutic ingredients for the HGD against RE. They play anti-inflammatory effects via down-regulating the pro-inflammatory cytokines and the conduction of p38MAPK/NF-κB signal. This research provides a comprehensive study on the active components, potential targets, and molecular mechanisms of HGD against RE. Moreover, the study supplies a feasible approach to reveal the mechanisms of TCM formula.

Association of Incidental Positron Emission Tomography Uptake in the Esophagus to Gastroesophageal Reflux Disease

The Los Angeles (LA) classification is the most accurate means of assessing esophageal injury from caustic gastric acid with focused and greater concentrations in areas of erosive disease.¹ However, data from animal models and patients have proposed that an initial diffuse inflammatory pathway contributes to injury in gastroesophageal reflux disease (GERD) mediated by interleukin (IL) 8, IL1β,^2,3 and hypoxia-inducible factors.^4,5 These observations demonstrate a lymphocyte predominant inflammatory process over course of 1-2 weeks associated with basal zone hyperplasia and dilation of intercellular spaces.⁶ In cultured human esophageal epithelial cells and patients, it is further suggested that acid causes this chronic inflammatory reaction.

Trends in gastroesophageal reflux disease research: A bibliometric and visualized study

Background

Gastroesophageal reflux disease (GERD), a disorder resulting from the retrograde flow of gastric contents into the esophagus, affects an estimated 10-30% of the Western population, which is characterized by multifactorial pathogenesis. Over the past few decades, there have been many aspects of uncertainty regarding GERD leading to an ongoing interest in the field as reflected by a large number of publications, whose heterogeneity and variable quality may present a challenge for researchers to measure their scientific impact, identify scientific collaborations, and to grasp actively researched themes in the GERD field. Accordingly, we aim to evaluate the knowledge structure, evolution of research themes, and emerging topics of GERD research between 2012 and 2022 with the help of bibliometric approaches.

Methods

The literature focusing on GERD from 2012 to 2022 was retrieved from the Science Citation Index Expanded of the Web of Science Core Collection. The overall publication performance, the most prolific countries or regions, authors, journals and resources-, knowledge- and intellectual-networking, as well as the co-citation analysis of references and keywords, were analyzed through Microsoft Office Excel 2019, CiteSpace, and VOSviewer.

Results

A total of 8,964 publications were included in the study. The USA published the most articles (3,204, 35.74%). Mayo Clin ranked first in the number of articles published (201, 2.24%). EDOARDO SAVARINO was the most productive author (86, 0.96%). The most productive journal in this field was SURGICAL ENDOSCOPY AND OTHER INTERVENTIONAL TECHNIQUES (304, 3.39%). AMERICAN JOURNAL OF GASTROENTEROLOGY had the most co-citations (4,953, 3.30%). Keywords with the ongoing strong citation bursts were transoral incision less fundoplication, eosinophilic esophagitis, baseline impedance, and functional heartburn.

Conclusion

For the first time, we obtained deep insights into GERD research through bibliometric analysis. Findings in this study will be helpful for scholars seeking to understand essential information in this field and identify research frontiers.

Pathophysiology of Pediatric Gastroesophageal Reflux Disease: Similarities and Differences With Adults

Gastroesophageal reflux (GOR) is defined as "the passage of gastric contents into the esophagus with or without regurgitation and vomiting" and gastroesophageal reflux disease (GORD) is defined "when GOR leads to troublesome symptoms affecting the daily functioning and/or complications." This definition was first developed in 2006 by the Montreal consensus group (1) and later on adopted by pediatric gastroenterology societies such as ESPGHAN and NASPGHAN in 2009 (2). The definition of gastroesophageal reflux reveals little about its pathophysiology and is focused on symptomatology. In this way, it acts as an umbrella term for the multifactorial causes of the disease and the various phenotypes encountered; from functional heartburn to hypersensitive esophagus and nonerosive reflux disease, to erosive esophagitis and Barrett's esophagus. This article is devoted to the pathophysiology of pediatric GORD in comparison to adult GORD and is divided in 2 parts. In the first part, we will systematically describe the different mechanisms for the generation and clearance of reflux events, while on the second part we will discuss the mechanisms involved in symptoms generation. Finally, we will discuss the similarities and differences between pediatric and adult GORD.

Changes in laryngopharyngeal reflux after uvulopalatopharyngoplasty for obstructive sleep apnea: An observational study

PURPOSE

To estimate laryngopharyngeal reflux (LPR) changes after uvulopalatopharyngoplasty (UPPP) for obstructive sleep apnea (OSA) using the reflux symptom index (RSI) and reflux finding score (RFS) questionnaires.

METHODS

A total of 91 participants were recruited and divided into three groups: control (n = 27), OSA mild to moderate (n = 29), and OSA severe (n = 35) groups according to polysomnography. All participants completed the preoperative RSI, and underwent blinded evaluation on videolaryngoscopy using the RFS questionnaire. Thirty-four OSA patients who underwent UPPP surgery completed postoperative polysomnography and questionnaires again after a 6-month follow-up.

RESULTS

The RSI score and RFS were higher in patients with OSA than in those without OSA. Patients with severe OSA also had a higher RSI score and RFS than those with mild to moderate OSA. Apnea and hypopnea index degree and percentage of recording time for <90% oxygen saturation showed positive correlation with LPR symptoms. But the lowest blood oxygen saturation during the recording time was negatively correlated with LPR symptoms. The mean RSI score and RFS before UPPP surgery were 15.88 ± 4.85 and 13.18 ± 4.80, after surgery decreasing to 9.53 ± 4.16 and 8.65 ± 4.87, respectively (P <.05). In 25 patients where surgery was successful, RSI scores, RFSs and individual RSI variables decreased after surgery.

CONCLUSIONS

LPR symptoms are common among OSA patients, and the coexistence of OSA and LPR cannot be ignored. Successful UPPP surgery potentially reduces LPR symptoms and improves laryngoscopic signs by alleviating sleep respiratory disorders. Level of Evidence: 3.

Carbonic Anhydrases II, IX, and XII in Reflux Esophagitis

BACKGROUND

The pathogenesis of gastroesophageal reflux disease (GERD) has not been resolved in detail. Esophageal epithelial cells provide resistance to acidic reflux via several mechanisms, many of which involve buffering acid with bicarbonate and transporting protons. Carbonic anhydrases (CAs) are enzymes that control the acid-base balance by catalyzing the reversible hydration of carbon dioxide to produce bicarbonate and hydrogen ions.

AIMS

We aimed to determine the immunohistochemical expression patterns of CAII, CAIX, and CAXII in the normal esophageal squamous epithelium and in patients with GERD.

METHODS

We evaluated 82 biopsy samples, including 26 with a histologically normal esophagus, 26 with histologically mild esophagitis, and 30 with severe esophagitis. Expression patterns of CAII, CAIX, and CAXII in the esophageal squamous epithelium were determined by immunohistochemical staining.

RESULTS

Cytoplasmic CAII expression was predominantly detected in the upper luminal part of the squamous epithelium and was significantly (p < 0.01) increased in GERD. Expression of CAIX was essentially membranous. The isozyme was constantly present in the peripapillary cells. In the interpapillary areas, clustered expression was observed to emerge and increase significantly (p < 0.01) in esophagitis. CAXII expression was the most abundant of the isozymes and was mainly membranous. In the normal squamous epithelium, CAXII expression was confined to the basal layer; in severe esophagitis, CAXII expression increased significantly in both basal (p < 0.05) and superficial (p < 0.01) halves of the epithelium.

CONCLUSIONS

We demonstrate upregulated expression of CAII, CAIX, and CAXII in GERD. The increase in expression likely contributes to esophageal epithelial resistance to acidic reflux.

Anti-Inflammation and Protective Effects of Anethum graveolens L. (Dill Seeds) on Esophageal Mucosa Damages in Reflux Esophagitis-Induced Rats

Anethum graveolens L. (dill seeds) are important medicinal and functional foods in Europe and central and south Asia, often used as a seasoning in daily diets. Anethum graveolens L. seeds (AGS) are used to treat indigestion and have shown physiological activities such as those against hypoglycemia and gastroesophageal disease. This study explored the protective effects of AGS extract on mucosal damages and inflammation in reflux esophagitis rats. AGS inhibited cellular inflammation including NO production and the expression of inflammatory proteins (iNOS and COX2 etc.), cytokines (IL-1β and TNF-α) and nuclear transfer factor related to NF-κB signaling caused by LPS stimulation in vitro. Furthermore, reflux esophagitis-induced rats were used to observe the anti-inflammatory effect of AGS. Tissue staining and inflammation-related protein expression of rats with acute reflux esophagitis indicated that AGS improved this inflammatory response, such as COX-2 and TNF-α in mucosa. In conclusion, AGS have good physiological activity and the possibility of being used as a medicinal food and a functional resource for the prevention and therapy of gastroesophageal diseases.

The role of hypoxia-inducible factors in the development of chronic pathology

This review highlights the current understanding of hypoxia-inducible factors (HIFs) role as regulators of oxygen-dependent reactions and inducers of genes expression in human organism. The focus is on the most significant relationships between the activation or inhibition of the HIFs intracellular system and development of the inflammatory process in various organs, chronic diseases of gastrointestinal tract, osteoarticular system, kidneys as well as hematological, endocrine and metabolic disorders.

Reflux esophagitis is associated with higher risks of acute stroke and transient ischemic attacks in patients hospitalized with atrial fibrillation: A nationwide inpatient sample analysis

Reflux esophagitis (RE) is a subset of gastroesophageal reflux disease (GERD) with endoscopic evidence of esophageal inflammation, which has been linked to an increased incidence of atrial fibrillation (AF). However, data on the effect of RE on patient outcomes is limited. We sought to examine the potential association of RE with outcomes of patients with AF in a nationwide study.The National Inpatient Sample (NIS) database was queried to identify hospitalized adult patients with AF and RE between 2010 and 2014. Primary outcomes included inpatient mortality, length of stay (LOS), and total hospital charges. AF related complications such as acute stroke, transient ischemic attack (TIA) and acute heart failure were assessed as secondary outcomes. Propensity score matching and multivariate regression analysis were used.Six lakh sixty seven thousands five hundred twenty patients were admitted for primary diagnosis of AF out of which 5396 had a secondary diagnosis of RE. In the AF with RE cohort, the average age was 73.6 years, 41.5% were male, and 79.9% were Caucasian. There was a greater prevalence of concomitant dyslipidemia, chronic liver disease and chronic pulmonary disease (P < .01) when compared to the AF without RE cohort. Patients with AF and RE also had higher incidence of acute strokes and TIAs (P < .05), longer LOS (P < .001), and higher hospital charges (P < .05) with no difference in acute heart failure (P = .08), hospital mortality (P = .12), or CHA2DS2-VASc score (P = .67).In hospitalized patients with AF, RE was associated with a higher rate of acute stroke and TIAs, longer LOS, and greater hospital charges.

Dihydroartemisinin prompts amplification of photodynamic therapy-induced reactive oxygen species to exhaust Na/H exchanger 1-mediated glioma cells invasion and migration

Photodynamic therapy (PDT) is a promising glioma therapy; however, its efficacy is compromised due to the PDT-induced reactive oxygen species (ROS) production being limited by the local hypoxic tumor microenvironment. Furthermore, Hypoxia activates sodium/hydrogen exchanger 1 (NHE1), an essential component for tumor progression and metastasis, enables glioma cells (GC) to escape PDT-mediated phototoxicity via increased H⁺ extrusion. However, interactions between NHE1 expression with ROS level involving response of GC remain unclear. Dihydroartemisinin (DHA), a ROS generator, has extensive anti-tumor effects. This study aimed to explore whether PDT along with DHA could amplify the total ROS levels and diminish GC invasion and migration by inhibiting NHE1 expression. Proliferation and invasion of U251 and LN229 cells were evaluated under different treatments using cell counting Kit-8 (CCK-8), transwell, and wound healing assays. ROS levels were measured using fluorescence probes and flow cytometry. NHE1 levels were detected by immunofluorescence and western blotting. Co-treatment effects and molecular events were further confirmed in a bilateral tumor-bearing nude mouse model. PDT with synergistic DHA significantly increased the total abundance of ROS to further suppress the invasion and migration of GC by reducing NHE1 levels in vitro. Using a bilateral glioma xenograft mouse model with primary and recurrent gliomas, we found that PDT markedly suppressed primary tumor growth, while PDT in synergy with DHA also suppressed recurrent tumors, and improved overall survival by regulating the ROS-NHE1 axis. No evident side effects were observed. Our results suggest that PDT with DHA can amplify the total ROS levels to weaken GC invasion and migration by suppressing NHE1 expression in vitro and in vivo, thus abolishing the resistance of GC to PDT. The synergistic therapy of PDT and DHA therefore represents a more efficient and safe strategy for comprehensive glioma treatment.

Optimal management of severe symptomatic gastroesophageal reflux disease

Gastroesophageal reflux disease (GERD) is a common disorder, and empirical proton pump inhibitor (PPI) treatment is often the first step of management; however, up to 40% of patients remain symptomatic despite PPI treatment. Refractory reflux refers to continued symptoms despite an adequate trial of PPI, and management remains challenging. The differential diagnosis is important; other oesophageal (e.g. eosinophilic oesophagitis) and gastroduodenal disorders (e.g. functional dyspepsia) should be ruled out, as this changes management. A combination of clinical assessment, endoscopic evaluation and in selected cases oesophageal function testing can help characterize patients with refractory reflux symptoms into oesophageal phenotypes so appropriate therapy can be more optimally targeted. Medical options then may include adding a H2 receptor antagonist, alginates, baclofen or antidepressant therapy, and there is emerging evidence for bile acid sequestrants and diaphragmatic breathing. The demonstration of a temporal association of symptoms with reflux events on pH-impedance testing (reflux hypersensitivity) serves to focus the management on modulating oesophageal perception and reducing the reflux burden, or identifies those with no obvious pathophysiologic abnormalities (functional heartburn). Anti-reflux surgery based on randomized controlled trial evidence has a role in reflux hypersensitivity or continued pathological acid reflux despite PPI in carefully considered, fully worked up cases that have failed medical therapy; approximately two of three cases will respond but there is a small risk of complications. In patients with persistent volume reflux despite medical therapy, given the lack of alternatives, anti-reflux surgery is a consideration. Promising newer approaches include endoscopic techniques. This review aims to summarize current diagnostic approaches and critically evaluates the evidence for the efficacy of available treatments.

Mucosal pathogenesis in gastro-esophageal reflux disease

BACKGROUND

Despite gastro-esophageal reflux disease affecting up to 20% of Western populations, relatively little is known about the molecular mechanisms underlying its most troublesome symptom: heartburn. Recent findings have unveiled the role of components of the esophageal mucosa in the pathogenesis of GERD including sensory nociceptive nerves and inflammatory mediators. Erosive esophagitis was long believed to develop as a result of acid injury at the esophageal lumen, but novel concepts suggest the generation of reflux-induced esophageal injury as a result of cytokine-mediated inflammation. Moreover, the localization and characterization of mucosal afferent nerves vary between GERD phenotypes and could explain the heterogeneity of symptom perception between patients who experience similar levels of acid reflux.

PURPOSE

The purpose of this review is to consider the crosstalk of different factors of the esophageal mucosa in the pathogenesis of GERD, with a particular focus on mucosal innervation and molecular basis of acid-induced cytokine response. We discuss the current understanding of the mucosal response to acid injury, the nociceptive role of acid-sensitive receptors expressed in the esophageal mucosa, and the role of esophageal epithelial cells in initiating the onset of erosive esophagitis.

Evaluation of Acute Mountain Sickness by Unsedated Transnasal Esophagogastroduodenoscopy at High Altitude

BACKGROUND & AIMS

It is not clear how rapid ascent to a high altitude causes the gastrointestinal symptoms of acute mountain sickness (AMS). We assessed the incidence of endoscopic lesions in the upper gastrointestinal tract in healthy mountaineers after a rapid ascent to high altitude, their association with symptoms, and their pathogenic mechanisms.

METHODS

In a prospective study, 25 mountaineers (10 women; mean age, 43.8 ± 9.5 y) underwent unsedated, transnasal esophagogastroduodenoscopy in Zurich (490 m) and then on 2 test days (days 2 and 4) at a high altitude laboratory in the Alps (Capanna Regina Margherita, 4559 m). Symptoms were assessed using validated instruments for AMS (the acute mountain sickness score and the Lake Louise scoring system) and visual analogue scales (scale, 0-100). Levels of messenger RNAs (mRNAs) in duodenal biopsy specimens were measured by quantitative polymerase chain rection.

RESULTS

The follow-up endoscopy at high altitude was performed in 19 of 25 patients on day 2 and in 23 of 25 patients on day 4. The frequency of endoscopic lesions increased from 12% at baseline to 26.3% on day 2 and to 60.9% on day 4 (P < .001). The incidence of ulcer disease increased from 0 at baseline to 10.5% on day 2 and to 21.7% on day 4 (P = .014). Mucosal lesions were associated with lower hunger scores (37.3 vs 67.4 in patients without lesions; P = .012). Subjects with peptic lesions had higher levels of HIF2A mRNA, which encodes a hypoxia-induced transcription factor, and ICAM1 mRNA, which encodes an adhesion molecule, compared with subjects without lesions (fold changes, 1.38 vs 0.63; P = .001; and 1.37 vs 0.66; P = .011, respectively).

CONCLUSIONS

In a prospective study of 25 mountaineers, fast ascent to a high altitude resulted in rapid onset of clinically meaningful mucosal lesions and ulcer disease. Duodenal biopsy specimens from these subjects had increased levels of HIF2A mRNA and ICAM1 mRNA, which might contribute to the formation of hypoxia-induced peptic lesions. Further studies are needed of the mechanisms of this process.

Tojapride Reverses Esophageal Epithelial Inflammatory Responses on Reflux Esophagitis Model Rats

OBJECTIVE

To investigate the mechanism of Tojapride, a Chinese herbal formula extract, on strengthening the barrier function of esophageal epithelium in rats with reflux esophagitis (RE).

METHODS

Ten out of 85 SD rats were randomly selected as the sham group (n10), and 75 rats were developed a reflux esophagitis model (RE) by the esophageal and duodenal side-to-side anastomosis. Fifty successful modeling rats were divided into different medicated groups through a random number table including the model, low-, medium-, and high-dose of Tojapride as well as omeprazole groups (n10). Three doses of Tojapride [5.73, 11.46, 22.92 g/(kg•d)] and omeprazole [4.17 mg/(kg•d)] were administrated intragastrically twice daily for 3 weeks. And the rats in the sham and model groups were administered 10 mL/kg distilled water. Gastric fluid was collected and the supernatant was kept to measure for volume, pH value and acidity. Esophageal tissues were isolated to monitor the morphological changes through hematoxylin-eosin (HE) staining, and esophageal epithelial ultrastructure was observed by transmission electron microscopy. The expressions of nuclear factor kappa-light-chain-enhancer of activated B cells p65 (NF-KBp65), κB kinase beta (IKKß), occludin, and zonula occludens-1 (ZO-1) in the esophageal tissues were measured by immunohistochemistry and Western blot, respectively.

RESULTS

The gastric pH value in the model group was significantly lower than the sham group (P<0.05). Compared with the model group, gastric pH value in the omeprazole and medium-dose of Tojapride groups were significantly higher (P<0.05). A large area of ulceration was found on the esophageal mucosa from the model rats, while varying degrees of congestion and partially visible erosion was observed in the remaining groups. Remarkable increase in cell gap width and decrease in desmosome count was seen in RE rats and the effect was reversed by Tojapride treatment. Compared with the sham group, the IKKß levels were significantly higher in the model group (P<0.05). However, the IKKß levels were down-regulated after treatment by all doses of Tojapride (P<0.01 or P<0.05). The occluding and ZO-1 levels decreased in the model group compared with the sham group (Ps0.01 or Ps0.05), while both indices were significantly up-regulated in the Tojapride-treated groups (P<0.01 or P<0.05).

CONCLUSIONS

Tojapride could improve the pathological conditions of esophageal epithelium in RE rats. The underlying mechanisms may involve in down-regulating the IKKß expression and elevating ZO-1 and occludin expression, thereby alleviating the inflammation of the esophagus and strengthening the barrier function of the esophageal epithelium.

Mechanism and Pathophysiology of Gastroesophageal Reflux Disease

Gastroesophageal reflux (GER) describes a process in which gastric contents travel retrograde into the esophagus. GER can be either a physiologic phenomenon that occurs in asymptomatic individuals or can potentially cause symptoms. When the latter occurs, this represents GER disease (GERD). The process by which GER transforms into GERD begins at the esophagogastric junction. Impaired clearance of the refluxate also contributes to GERD. Reflux causes degradation of esophageal mucosal defense. The refluxate triggers sensory afferents leading to symptom generation.

New Developments in the Diagnosis and Management of Gastroesophageal Reflux

PURPOSE OF REVIEW

To examine recent key developments in the pathophysiology, diagnosis, and treatment of gastroesophageal reflux disease (GERD).

RECENT FINDINGS

Newer research has suggested cytokine-mediated inflammation may play a role in the physiology of GERD, implying that the underlying mechanism may not be entirely related to chemical damage due to acid. Aided by novel technologies, diagnostic testing is also moving toward elucidating individual mechanisms and better defining specific GERD phenotypes with the goal of providing directed therapy. This is especially important in current times given the increase in coverage of adverse events reportedly linked to long-term proton pump inhibitor use.

SUMMARY

As patients are looking for potential alternatives, we highlight the key recent updates in pathophysiology and understanding of GERD and current medical and endoscopic/surgical options and explore the exciting treatments in the pipeline.

Cdx2 Animal Models Reveal Developmental Origins of Cancers

The Cdx2 homeobox gene is important in assigning positional identity during the finely orchestrated process of embryogenesis. In adults, regenerative responses to tissues damage can require a replay of these same developmental pathways. Errors in reassigning positional identity during regeneration can cause metaplasias-normal tissue arising in an abnormal location-and this in turn, is a well-recognized cancer risk factor. In animal models, a gain of Cdx2 function can elicit a posterior shift in tissue identity, modeling intestinal-type metaplasias of the esophagus (Barrett's esophagus) and stomach. Conversely, loss of Cdx2 function can elicit an anterior shift in tissue identity, inducing serrated-type lesions expressing gastric markers in the colon. These metaplasias are major risk factors for the later development of esophageal, stomach and colon cancer. Leukemia, another cancer in which Cdx2 is ectopically expressed, may have mechanistic parallels with epithelial cancers in terms of stress-induced reprogramming. This review will address how animal models have refined our understanding of the role of Cdx2 in these common human cancers.

Epithelial HIF-1α/claudin-1 axis regulates barrier dysfunction in eosinophilic esophagitis

Epithelial barrier dysfunction is a significant factor in many allergic diseases, including eosinophilic esophagitis (EoE). Infiltrating leukocytes and tissue adaptations increase metabolic demands and decrease oxygen availability at barrier surfaces. Understanding of how these processes impact barrier is limited, particularly in allergy. Here, we identified a regulatory axis whereby the oxygen-sensing transcription factor HIF-1α orchestrated epithelial barrier integrity, selectively controlling tight junction CLDN1 (claudin-1). Prolonged experimental hypoxia or HIF1A knockdown suppressed HIF-1α-dependent claudin-1 expression and epithelial barrier function, as documented in 3D organotypic epithelial cultures. L2-IL5OXA mice with EoE-relevant allergic inflammation displayed localized eosinophil oxygen metabolism, tissue hypoxia, and impaired claudin-1 barrier via repression of HIF-1α/claudin-1 signaling, which was restored by transgenic expression of esophageal epithelial-targeted stabilized HIF-1α. EoE patient biopsy analysis identified a repressed HIF-1α/claudin-1 axis, which was restored via pharmacologic HIF-1α stabilization ex vivo. Collectively, these studies reveal HIF-1α's critical role in maintaining barrier and highlight the HIF-1α/claudin-1 axis as a potential therapeutic target for EoE.

Prediagnostic circulating markers of inflammation and risk of oesophageal adenocarcinoma: a study within the National Cancer Institute Cohort Consortium

OBJECTIVE

Cross-sectional data indicate that systemic inflammation is important in oesophageal adenocarcinoma. We conducted a prospective study to assess whether prediagnostic circulating markers of inflammation were associated with oesophageal adenocarcinoma and to what extent they mediated associations of obesity and cigarette smoking with cancer risk.

DESIGN

This nested case-control study included 296 oesophageal adenocarcinoma cases and 296 incidence density matched controls from seven prospective cohort studies. We quantitated 69 circulating inflammation markers using Luminex-based multiplex assays. Conditional logistic regression models estimated associations between inflammation markers and oesophageal adenocarcinoma, as well as direct and indirect effects of obesity and smoking on risk of malignancy.

RESULTS

Soluble tumour necrosis factor receptor 2 (sTNFR2) (ORsquartile 4 vs 1=2.67, 95% CI 1.52 to 4.68) was significantly associated with oesophageal adenocarcinoma. Additional markers close to the adjusted significance threshold included C reactive protein, serum amyloid A, lipocalin-2, resistin, interleukin (IL) 3, IL17A, soluble IL-6 receptor and soluble vascular endothelial growth factor receptor 3. Adjustment for body mass index, waist circumference or smoking status slightly attenuated biomarker-cancer associations. Mediation analysis indicated that sTNFR2 may account for 33% (p=0.005) of the effect of waist circumference on oesophageal adenocarcinoma risk. Resistin, plasminogen activator inhibitor 1, C reactive protein and serum amyloid A were also identified as potential mediators of obesity-oesophageal adenocarcinoma associations. For smoking status, only plasminogen activator inhibitor 1 was a nominally statistically significant (p<0.05) mediator of cancer risk.

CONCLUSION

This prospective study provides evidence of a link between systemic inflammation and oesophageal adenocarcinoma risk. In addition, this study provides the first evidence that indirect effects of excess adiposity and cigarette smoking, via systemic inflammation, increase the risk of oesophageal adenocarcinoma.

Some of the effective factors in the pathogenesis of gastro-oesophageal reflux disease

Oesophageal adenocarcinoma is one of the most fatal tumours to affect the digestive tract and is the eighth most common malignancy worldwide. Gastro‐oesophageal reflux has an important role in the incidence of adenocarcinoma of the oesophagus. Gastro‐oesophageal reflux disease (GERD) is a multifactorial, acid‐peptic disorder that results from the reflux of noxious material from the stomach into the oesophagus. The refluxed material causes the occurrence of oesophageal inflammation which creates a condition that is called reflux oesophagitis. The prevalence of this disease has increased dramatically in recent decades, mostly in the western world, where it affects about 10% to 30% of the population. The aetiology of oesophageal mucosal damage is complicated. Many inflammatory mediators are produced within the gastrointestinal (GI) tract, but their contributions in pathophysiology and disease pathogenesis have not been well investigated. Despite the protective barrier provided by the oesophageal mucosa, refluxed materials can cause oxidative injury and in?ammatory responses that involve the epithelium and immune cells. The analysing cellular events in gastro‐ oesophageal reflux disease and physiological responses to such conditions are important and necessary for a better grasp of the pathogenesis of GERD and the expansion of new treatments. Therefore, we want to discuss some of the important and key factors of GERD disease in this article.

Aspirin prevents NF-κB activation and CDX2 expression stimulated by acid and bile salts in oesophageal squamous cells of patients with Barrett's oesophagus

OBJECTIVE

In previous studies using oesophageal squamous cells from patients with Barrett's oesophagus (normal oesophageal squamous (NES)-B cells) and from patients without Barrett's oesophagus (NES-G cells), we showed that acid and bile salts induced caudal-related homeobox transcription factor 2 (CDX2) expression only in NES-B cells. CDX2, a transcription factor required to form intestinal epithelium, is a target of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) signalling, which can be inhibited by aspirin. We explored mechanisms underlying differences between NES-B and NES-G cells in CDX2 expression and effects of aspirin on that CDX2 expression.

DESIGN

We exposed NES-B and NES-G cells to acid and bile salts, with and without aspirin, and evaluated effects on IκB-NF-κB-PKAc complex activation, p65 NF-κB subunit function, and CDX2 expression.

RESULTS

In both NES-B and NES-G cells, acid and bile salts activated nicotinamide adenine dinucleotide phosphate oxidase to generate H₂O₂, which activated the IκB-NF-κB-PKAc complex. NES-B cells exhibited higher levels of phosphorylated IκB and p65 and greater NF-κB transcriptional activity than NES-G cells, indicating greater IκB-NF-κB-PKAc complex activation by acid and bile salts in NES-B cells, and p65 siRNA prevented their increased expression of CDX2. Aspirin blocked IκB phosphorylation, p65 nuclear translocation, CDX2 promoter activation and CDX2 expression induced by acid and bile salts in NES-B cells.

CONCLUSIONS

Differences between NES-B and NES-G cells in NF-κB activation by acid and bile salts can account for their differences in CDX2 expression, and their CDX2 expression can be blocked by aspirin. These findings might explain why some patients with GORD develop Barrett's oesophagus while others do not, and why aspirin might protect against development of Barrett's oesophagus.

A new paradigm for GERD pathogenesis. Not acid injury, but cytokine-mediated inflammation driven by HIF-2α: a potential role for targeting HIF-2α to prevent and treat reflux esophagitis

Traditionally, reflux esophagitis was assumed to develop as a caustic, chemical injury inflicted by refluxed acid. Recently, however, studies in rats and humans suggest that reflux esophagitis develops as a cytokine-mediated inflammatory injury, with hypoxia inducible factor (HIF)-2α playing a major role. In response to the reflux of acid and bile, HIF-2α in esophageal epithelial cells becomes stabilized, thereby increasing production of pro-inflammatory cytokines that attract T lymphocytes and other inflammatory cells to damage the esophagus. Recent studies have identified small molecule inhibitors of HIF-2α that demonstrate exquisite isoform selectivity, and clinical trials for treatment of HIF-2α-driven kidney cancers are ongoing. It is conceivable that a HIF-2α-directed therapy might be a novel approach to prevention and treatment of reflux esophagitis.

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.

Reflux esophagitis and its role in the pathogenesis of Barrett's metaplasia

Reflux esophagitis damages the squamous epithelium that normally lines the esophagus, and promotes replacement of the damaged squamous lining by the intestinal metaplasia of Barrett's esophagus, the precursor of esophageal adenocarcinoma. Therefore, to prevent the development of Barrett's metaplasia and esophageal adenocarcinoma, the pathogenesis of reflux esophagitis must be understood. We have reported that reflux esophagitis, both in a rat model and in humans, develops as a cytokine-mediated inflammatory injury (i.e., cytokine sizzle), not as a caustic chemical injury (i.e., acid burn), as traditionally has been assumed. Moreover, reflux induces activation of hypoxia inducible factor (HIF)-2α, which enhances the transcriptional activity of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) causing increases in pro-inflammatory cytokines and in migration of T lymphocytes, an underlying molecular mechanism for this cytokine-mediated injury. In some individuals, reflux esophagitis heals with Barrett's metaplasia. A number of possibilities exist for the origin of the progenitor cells that give rise to this intestinal metaplasia including those of the esophagus, the proximal stomach, or the bone marrow. However, intestinal cells are not normally found in the esophagus, the stomach, or the bone marrow. Thus, the development of Barrett's intestinal metaplasia must involve some molecular reprogramming of key developmental transcription factors within the progenitor cell, a process termed transcommitment, which may be initiated by the noxious components of the gastric refluxate. This review will highlight recent studies on the pathogenesis of reflux esophagitis and on reflux-related molecular reprogramming of esophageal squamous epithelial cells in the pathogenesis of Barrett's metaplasia.