Dilated intercellular spaces as a marker of GERD

Functional Dyspepsia and Gastroesophageal Reflux Disease: From Pathogenesis to Current Treatment Strategies

Aim: to present a modern view on the combination of functional dyspepsia (FD) and gastroesophageal reflux disease (GERD) and to evaluate the effectiveness of acotiamide in patients with FD and GERD.

Key points. The high frequency of the combination of FD and GERD is caused by common pathogenetic mechanisms and presents an urgent problem in clinical practice. The concurrent occurrence of these diseases alters the clinical picture, complicates differential diagnostics, and leads to inadequate prescription of drugs. Medical treatment for patients with FD and GERD includes the use of proton pump inhibitors (PPIs) and prokinetics. Currently, acotiamide is recognized as an effective drug that affects the motility of the upper gastrointestinal tract. Acotiamide is an antagonist of muscarinic M1 and M2 receptors and a reversible inhibitor of acetylcholinesterase. The clinical efficacy of this drug has been demonstrated not only in patients with FD but also in those with a combination of FD and GERD.

Conclusion. Administration of acotiamide is pathogenetically justified in patients with the combination of GERD and FD.

Morphological and Redox/Glycative Alterations in the PCOS Oviducts: Modulating Effects of Carnitines in PCOS Mice

Polycystic ovarian syndrome (PCOS) is a heterogeneous condition characterized by hyperandrogenism (HA), polycystic ovaries, and dysfunctional ovulation, and it is associated with metabolic problems such as insulin resistance (IR) and obesity. After having investigated the morphological and antioxidant/antiglycative alterations on mouse ovaries and uteri, we here focus on PCOS oviducts, a tract of the reproductive system essential for the nourishment and transport of gametes and embryos. The modulating effects of L-carnitine (LC) and acetyl-L-carnitine (ALC) were also assessed. CD1 mice were administered or not with dehydroepiandrosterone (DHEA, 6 mg/100 g body weight) for 20 days, alone or with 0.40 mg of L-carnitine (LC) and 0.20 mg of acetyl-L-carnitine (ALC). Oviducts were then subjected to histology and immunohistochemistry to evaluate their morphology and collagen deposition, and steroidogenesis. Oxidative, mitochondrial, and methylglyoxal (MG)-dependent damage was also investigated. Transmission electron microscopy was used to detect ultrastructural alterations. The PCOS oviducts were affected by hyperfibrosis, hyperplasia, hypertrophy, and altered steroidogenesis, with oxidative alterations associated with MethylGlyoxal-Advanced Glycation End product (MG-AGE) accumulation. A reduced ciliary coverage and numerous dilated intercellular spaces were found in the epithelium. LC-ALC administration mitigated PCOS oviductal alterations. These results provide evidence for the detrimental action of oxidative and glycative stress in PCOS oviducts, confirming a protective role of carnitines on the PCOS phenotype.

Esophageal Baseline Impedance is Associated with Laryngopharyngeal Reflux and Treatment Response

OBJECTIVE

To evaluate the efficacy of distal esophageal mean nocturnal baseline impedance (MNBI), a general marker of esophageal mucosal barrier integrity, in predicting laryngopharyngeal reflux (LPR) and symptomatic response to acid reflux therapy.

METHODS

This retrospective study analyzed 173 patients who presented with symptoms of laryngopharyngeal reflux and underwent 24-h multichannel intraluminal impedance-pH (MII-pH) testing. Mean nocturnal baseline impedance values were calculated and assessed for their association and ability to predict LPR symptoms, MII-pH results, treatment response, and other markers of LPR.

RESULTS

Notably, 153 of the 173 patients were tested off acid suppression medication and included in statistical analysis. Based on the MII-pH probe data, 108 (71%) patients had LPR, 8 (5%) had gastroesophageal reflux disease (GERD), and 37 (24%) were without pathologic reflux. Distal esophageal MNBI of LPR patients was significantly lower in LPR patients than patients with negative studies (1332 ± 94.8 vs. 2158 ± 173.5, p = 0.001). Among 118 patients who trialed antireflux therapy, a distal esophageal MNBI cutoff value of <1580 Ω was an independent predictor of treatment response (OR = 4.148 [1.877-9.189]). This value better predicted improvement with antireflux therapy for LPR than other objective MII-pH probe data, which were not independent predictors of treatment response.

CONCLUSION

Distal esophageal MNBI values may have value in the diagnosis of LPR and potentially predict medication responsiveness in LPR patients.

LEVEL OF EVIDENCE

3 Laryngoscope, 134:4071-4077, 2024.

Syndrome of increased epithelial permeability: opportunities of current pharmacotherapy

Syndrome of increased epithelial permeability (SPEP) is considered as one of the universal mechanisms that determine the subsequent development of chronic systemic inflammation of varying severity. Studies carried out in the last 10 years have shown the important role of SPEP in the pathogenesis of many diseases of internal organs, and, first of all, of the gastrointestinal diseases. The article discusses possible ways of correcting impaired epithelial permeability from the point of view of the cytoprotective effects of drugs most often prescribed to patients with gastrontestinal diseases.

Correlation of Esophageal Mean Nocturnal Baseline Impedance With Markers of Laryngopharyngeal Reflux

OBJECTIVES

Mean nocturnal baseline impedance (MNBI) is a measure of the esophageal epithelial barrier function calculated via high-resolution impedance manometry and can be used as a diagnostic tool and treatment response predictor for gastroesophageal reflux disease (GERD). However, its utility for laryngopharyngeal reflux (LPR) has been minimally studied. We aimed to investigate the relationship of MNBI between patients with suspected LPR, healthy controls, and their 24-h multichannel intraluminal impedance-pH (MII-pH) study results.

METHODS

Retrospective patient series analysis was performed of patients with suspected LPR and healthy controls who underwent 24-h MII-pH monitoring. MNBI values were calculated from impedance channels at the level of the hypopharynx, proximal esophagus, and distal esophagus. We compared these MNBI values between the subject groups with secondary analysis on MII-pH results, reflux symptom index, reflux findings score, DeMeester score, and salivary pepsin levels.

RESULTS

Twenty-three patients with suspected LPR and 14 healthy controls were enrolled. Decreased distal esophageal MNBI was found to be significantly decreased in patients with suspected LPR compared with healthy controls (p < 0.01) and in subjects with positive MII-pH studies compared to negative MII-pH studies (p < 0.01). There were no significant correlations of MNBI at the hypopharynx or proximal esophagus.

CONCLUSION

Distal esophageal MNBI has significant correlations with many phenotypic and biological markers of LPR. These findings indicate that MNBI has the potential to be applied to LPR, similar to its emerging use as a diagnostic tool and treatment response predictor for GERD.

LEVEL OF EVIDENCE

3 Laryngoscope, 2022.

Eosinophilic esophagitis: Immune mechanisms and therapeutic targets

Eosinophilic esophagitis (EoE) is an emerging chronic inflammatory disease of the oesophagus and is clinically characterized by upper gastrointestinal (GI) symptoms including dysphagia and esophageal food impaction. Histopathologic manifestations, which include intraepithelial eosinophilic inflammation and alterations of the esophageal squamous epithelium, such as basal zone hyperplasia (BZH) and dilated intercellular spaces (DIS), are thought to contribute to esophageal dysfunction and disease symptoms. Corroborative clinical and discovery science-based studies have established that EoE is characterized by an underlying allergic inflammatory response, in part, related to the IL-13/CCL26/eosinophil axis driving dysregulation of several key epithelial barrier and proliferative regulatory genes including kallikrein (KLK) serine proteases, calpain 14 (CAPN14) and anoctamin 1 (ANO1). The contribution of these inflammatory and proliferative processes to the clinical and histological manifestations of disease are not fully elucidated. Herein, we discuss the immune molecules and cells that are thought to underlie the clinical and pathologic manifestations of EoE and the emerging therapeutics targeting these processes for the treatment of EoE.

Application of electron microscopy in gastroenterology

Electron microscopy has long been used in research in the fields of life sciences and materials sciences. Transmission and scanning electron microscopy and energy-dispersive X-ray spectroscopy (EDX) analyses have also been performed in the field of gastroenterology. Electron microscopy and EDX enable (1) Observation of ultrastructural differences in esophageal epithelial cells in patients with gastroesophageal reflux and eosinophilic esophagitis; (2) Detection of lanthanum deposition in the stomach and duodenum; (3) Ultrastructural and elemental analyses of enteroliths and bezoars; (4) Detection and characterization of microorganisms in the gastrointestinal tract; (5) Diagnosis of gastrointestinal tumors with neuroendocrine differentiation; and (6) Analysis of gold nanoparticles potentially used in endoscopic photodynamic therapy. This review aims to foster a better understanding of electron microscopy applications by reviewing relevant clinical studies, basic research findings, and the state of current research carried out in gastroenterology science.

Proton Pump Inhibitor Therapy for Eosinophilic Esophagitis: History, Mechanisms, Efficacy, and Future Directions

Over the past decade, the role of proton pump inhibitor (PPI) medication has evolved from a diagnostic tool for Eosinophilic Esophagitis (EoE), by excluding patients with PPI responsive esophageal eosinophilia (PPI-REE), to a therapy for EoE. This transition resulted from the Updated International Consensus Diagnostic Criteria for Eosinophilic Esophagitis: Proceedings of the Appraisal of Guidelines for Research and Evaluation II (AGREE) Conference to support PPI therapy for EoE in children and adults. Additional recent advances have suggested a role for genetic variations that might impact response to PPI therapy for EoE. This review article will explore a brief background of EoE, the evolution of PPI therapy for EoE and its proposed mechanisms, efficacy and safety in children and adults, and considerations for future PPI precision medicine in patients with EoE.

theLiTE™: A Screening Platform to Identify Compounds that Reinforce Tight Junctions

Tight junctions (TJ) are formed by transmembrane and intracellular proteins that seal the intercellular space and control selective permeability of epithelia. Integrity of the epithelial barrier is central to tissue homeostasis and barrier dysfunction has been linked to many pathological conditions. TJ support the maintenance of cell polarity through interactions with the Par complex (Cdc42-Par-6-Par-3-aPKC) in which Par-6 is an adaptor and links the proteins of the complex together. Studies have shown that Par-6 overexpression delays the assembly of TJ proteins suggesting that Par-6 negatively regulates TJ assembly. Because restoring barrier integrity is of key therapeutic and prophylactic value, we focus on finding compounds that have epithelial barrier reinforcement properties; we developed a screening platform (theLiTE™) to identify compounds that modulate Par-6 expression in follicular epithelial cells from Par-6-GFP Drosophila melanogaster egg chambers. Hits identified were then tested whether they improve epithelial barrier function, using measurements of transepithelial electrical resistance (TEER) or dye efflux to evaluate paracellular permeability. We tested 2,400 compounds, found in total 10 hits. Here we present data on six of them: the first four hits allowed us to sequentially build confidence in theLiTE™ and two compounds that were shortlisted for further development (myricetin and quercetin). We selected quercetin due to its clinical and scientific validation as a compound that regulates TJ; food supplement formulated on the basis of this discovery is currently undergoing clinical evaluation in gastroesophageal reflux disease (GERD) sufferers.

Gastroesophageal reflux disease: new approaches to optimizing pharmacotherapy

Proton pump inhibitors (PPIs) are baseline drugs for induction and maintenance of remission in gastroesophageal reflux disease (GERD). PPIs have proven to be highly effective in healing esophageal mucosal lesions and relieving the symptoms of the disease in most cases. However, according to the literature data, the incidence rate of clinical ineffectiveness of PPIs in the form of partial or complete persistence of current symptoms during administration of standard doses of PPIs ranges from 10 to 40%. Optimization of GERD therapy in PPI refractory patients is a significant challenge. In most cases, experts advise to increase a dose / dosage frequency of PPIs, switch to CYP2C19-independent PPIs (rabeprazole, esomeprazole, dexlansoprazole), add an esophagoprotective or promotility agents to therapy. At the same time, these recommendations have a limited effect in some patients, which opens up opportunities for looking for new solutions related to the optimization of GERD therapy. Today there is growing evidence of the relevance of the role of disruption of the cytoprotective and barrier properties of the esophageal mucosa in the genesis of GERD and the formation of refractoriness. Intercellular contacts ensure the integrity of the barrier function of the esophageal mucosa to protect it from various exogenous intraluminal substances with detergent properties. Acid-peptic attack in patients with GERD leads to alteration of the expression of some tight junction proteins in epithelial cells of the esophageal mucosa. The latter leads to increased mucosal permeability, which facilitates the penetration of hydrogen ions and other substances into the submucosal layer, where they stimulate the terminals of nerve fibers playing a role in the induction and persistence of the symptoms of the disease. The above evidence brought up to date the effectiveness study of the cytoprotective drugs with tropism to the gastrointestinal tract, as part of the combination therapy of GERD.

Correlation between pre-operative endoscopic findings with reflux symptom score for gastro-oesophageal reflux disease in bariatric patients

Introduction:

There is a strong association between gastro-oesophageal reflux disease and morbid obesity.

Methods:

Two hundred and eleven morbidly obese patients operated between September 2007 and June 2017 were retrospectively reviewed. All patients underwent pre-operative upper gastrointestinal endoscopy and assessment by reflux symptomatic score questionnaire.

Results:

Of the total 211 patients, 156 (73.94%) were females; mean body mass index of the cohort was 46.23 ± 3.1 kg/m². There was no evidence of Barrett's oesophagus or malignancy on pre-operative endoscopy. 63.04% of the patients (n = 133) in the study cohort had normal endoscopy. Pre-operative evaluation by reflux symptom score (RSS) questionnaire revealed no evidence of gastro-oesophageal reflux disease in 61.13% of patients (n = 129). The total number of patients with symptoms was 82 (38.86%). They were further divided into two categories based on severity of symptoms, namely, mild + moderate 60 (73.17%) and severe + very severe 22 (26.83%). From the cohort of symptomatic patients, the sub-cohort of 60 mild + moderate symptomatic patients had equal number of patients with normal 30 (50%) and abnormal endoscopy 30 (50%). In the sub-cohort of patients with severe + very severe symptoms (n = 22; 26.83%), endoscopy was abnormal in 6 (27.7%) patients. Whereas, out of 129 (61.13%) asymptomatic patients, one-third (n = 42) had abnormal endoscopy. The weighted kappa score was used between pre-operative endoscopic findings and RSS was statistically not significant (k - 0.0986).

Conclusion:

Pre-operative endoscopy is a must in all bariatric patients as significant percentage of asymptomatic patients can have abnormal endoscopy and vice versa.

[Rebamipide: evidence base for use in gastroenterology]

Rebamipide is a cytoprotective drug that has been used in practical gastroenterology for 30 years. This article summarizes the main results of the most relevant clinical studies of rebamipide in diseases of various parts of the gastrointestinal tract, including the esophagus, stomach, small and large intestine.

Duration of adhesion of swallowed alginates to distal oesophageal mucosa: implications for topical therapy of oesophageal diseases

BACKGROUND

We have previously shown, ex vivo, that alginate solutions can have a topical protective effect on oesophageal mucosal biopsies exposed to simulated gastric juice. Oesophageal mucosal impedance can measure the duration of mucosal adherence of ionic solutions since the impedance drops when the solution is present, and rises to baseline as the solution clears.

AIM

To investigate the in vivo duration of adhesion of swallowed alginate solution to distal oesophageal mucosa.

METHODS

We studied 20 healthy volunteers and 10 patients with heartburn. A pH-impedance catheter was inserted, and baseline distal channel oesophageal impedance measured. Healthy volunteers received 10 mL of either sodium alginate (Gaviscon Advance), Gaviscon placebo (no alginate) or viscous slurry (saline mixed with sucralose), given in a randomised, single-blinded order over three visits. Patients received either sodium alginate or placebo on two visits. Initial impedance drop was measured, then 1-minute mean impedance was measured each minute until ≥75% recovery to baseline.

RESULTS

In healthy volunteers, sodium alginate adhered to the oesophageal mucosa for longer than placebo or viscous slurry (10.4 [8.7] minutes vs 1.1 [1.6] vs 3.6 [4.0], P < 0.01). In patients, sodium alginate adhered to the oesophageal mucosa for longer than placebo (9.0 (5.4) vs 3.7 (4.1), P < 0.01).

CONCLUSIONS

Sodium alginate solution adhered to the oesophageal mucosa for significantly longer than placebo or viscous slurry. This demonstrates that alginates could confer a protective benefit due to mucoadhesion and can be a basis for further development of topical protectants and for topical drug delivery in oesophageal disease.

Distal Esophageal Impedance Measured by High-resolution Esophageal Manometry With Impedance Suggests the Presence of Barrett's Esophagus

Background/Aims

Barrett's esophagus (BE) is characterized by intestinal metaplasia in the distal esophagus. The aims of this study are to: (1) Compare baseline distal esophageal impedance (DEI) using high-resolution esophageal manometry with impedance (HREMI) in patients with BE, esophagitis, and healthy volunteers and (2) Correlate length of low impedance on HREMI in patients with BE to the length of endoscopic BE.

Methods

Patients with BE or esophagitis who underwent HREMI were included. Ten volunteers had HREMI. Baseline DEI was calculated from HREMI using the landmark segment. In patients with BE, the impedance was plotted to measure the extent of plotted low impedance (PLI) and visual low impedance (VLI). Lengths of VLI and PLI were correlated to endoscopic length of BE by Prague score.

Results

Forty-five patients were included (16 BE; 19 esophagitis; 10 volunteers). BE patients had lower baseline DEI at the first, second, and third sensors above the lower esophageal sphincter (mean ± SEM: 1.37 ± 0.45, 0.97 ± 0.27, and 0.81 ± 0.20) compared to volunteers (8.73 ± 0.60, 8.20 ± 0.73, and 6.94 ± 0.99; P < 0.001). Baseline DEI was lower in BE than esophagitis patients (2.98 ± 0.65, 2.49 ± 0.56, and 2.01 ± 0.51) at the first, second, and third sensors (P < 0.052 for second and third sensors); ie, BE < esophagitis < controls. PLI and VLI had a stronger correlation to circumferential score (r² = 0.84 and 0.83) than maximal score (r² = 0.76 and 0.68).

Conclusions

Baseline DEI is lower in BE compared with esophagitis and healthy volunteers. The length of low impedance correlates to the endoscopic extent of BE. Thus, impedance values during HREMI may help suggest the presence and extent of BE or esophagitis.

Changes in Pharyngeal Baseline Impedance in Patients With Laryngopharyngeal Reflux

Objective

Few studies have investigated pharyngeal intraluminal baseline impedance (BI) levels in patients with laryngopharyngeal reflux (LPR). The aim of this study was to compare intraluminal BI levels between patients with LPR and healthy controls.

Study Design

Retrospective case series.

Setting

Tertiary care medical center.

Subjects and Methods

We conducted a retrospective analysis of 24-hour multichannel intraluminal impedance (MII)–pH monitoring results from patients with suspected LPR complaining of reflux symptoms. Patients with suspected LPR were divided into 2 groups according to the 24-hour MII-pH monitoring (LPR group: patients with symptoms with reflux events ≥1, symptom but no reflux [SNR] group: patients with symptoms but no reflux event). Healthy controls were recruited and also underwent 24-hour MII-pH monitoring. We compared the esophageal and pharyngeal BI levels and ratios between 3 groups.

Results

Pharyngeal BI levels in the LPR group were significantly higher than in the healthy controls. In addition, the pharyngeal BI levels in the SNR group were significantly higher than in the healthy controls. All ratios of pharyngeal to distal esophageal BI levels in the LPR and SNR group were significantly higher than in the healthy controls. However, there were no significant differences in esophageal BI levels and ratios between the 3 groups.

Conclusion

We found that the pharyngeal BI levels were higher in patients with LPR than in healthy controls. In addition, the pharyngeal BI levels measured by 24-hour MII-pH monitoring in patients with LPR symptoms, but without a reflux episode, were higher than in the healthy controls.

Baseline Impedance Measured During High-resolution Esophageal Impedance Manometry in Patients With Rumination Syndrome is as Abnormal as in Patients With GERD

GOALS AND BACKGROUND

Baseline impedance measured during high-resolution impedance manometry (HRIM) can distinguish patients with gastroesophageal reflux disease (GERD) from controls, presumably due to differences in esophageal acid exposure. The characteristics of regurgitation and reflux in rumination syndrome and GERD are very different, and thus we investigated whether baseline esophageal impedance would differ in these 2 patient groups compared with controls.

STUDY

We compared 20 patients with rumination syndrome with 20 patients who had GERD and 40 controls. Baseline impedance was measured over 15 seconds during the landmark period of HRIM in all 18 impedance sensors on a HRIM catheter.

RESULTS

The mean distal baseline impedance measured in ohms during HRIM was 1336 Ω [95% confidence interval (CI)=799, 1873) in patients with GERD, 1536 Ω in rumination syndrome (95% CI=1012, 2061), and 3379 Ω in controls (95% CI=2999, 3759) (P<0.0001). Proximal impedance was significantly lower in the GERD and rumination groups compared with controls; rumination syndrome (2026; 95% CI=1493, 2559 Ω), GERD (2572; 95% CI=2027, 3118 Ω), and controls (3412; 95% CI=3026, 3798 Ω) (P<0.001).

CONCLUSIONS

Baseline impedance measured during HRIM in patients with rumination syndrome is significantly lower than controls and appears similar to patients with GERD both in the proximal and distal esophagus. These findings suggest that the postprandial regurgitation in rumination syndrome alters both the distal and proximal esophageal mucosal barrier.

Gastroesophageal reflux in cystic fibrosis across the age spectrum

Background

Scientific advances have improved longevity in cystic fibrosis (CF) patients and many of these patients can expect to experience age-related gastrointestinal co-morbidities. We aimed to assess the extent to which age might impact gastroesophageal reflux (GER) in patients with CF.

Methods

Our esophageal pH-multichannel intraluminal impedance monitoring database was searched for tracings belonging to CF patients ≥2 years old without prior fundoplication and not taking anti-reflux medications immediately prior (within 7 days) and during the study. Tracings were retrospectively analyzed; Impedance and pH variables were evaluated with respect to age and pulmonary function.

Results

Twenty-eight patients were enrolled; 16 children (3.1-17.7 years) and 12 adults (18.2-48.9 years). Among pH probe parameters, correlation analysis showed DeMeester score (P=0.011) and number of acid reflux events lasting >5 minutes (P=0.047) to be significantly correlated with age. Age was not significantly correlated with any of the impedance parameters. Age was negatively correlated with baseline impedance (BI) in the distal esophagus (r=-0.424, P=0.023) and BI was negatively correlated with several pH parameters, including reflux index (r=-0.553, P=0.002), number of total acid reflux events (r=-0.576, P=0.001), number of acid reflux events lasting >5 minutes (r=-0.534, P=0.003), and DeMeester score (r=-0.510, P=0.006). Pulmonary function (percent predicted forced expiratory volume in one minute; ppFEV₁) was negatively correlated with age (r=-0.494, P=0.0007). The interaction of age and ppFEV₁ and any of the reflux parameters, however, was not significant (P>0.05); the strongest evidence for an interaction was found for the number of acid reflux events reaching the proximal esophagus, but this interaction still did not reach statistical significance (P=0.070).

Conclusions

In a small cohort, we found evidence that age may be associated with increased acid exposure and that both age and increased acid exposure are associated with reduced BI in the distal esophagus. The negative relationship between pulmonary function and age in our cohort is not related to GER. This pilot study supports the need for esophageal assessment and treatment of GER as standard components of clinical care for an aging CF population.

Current advances in the treatment of gastroesophageal reflux disease: a focus on esophageal protection

Gastroesophageal reflux disease (GERD) is characterized by high morbidity and a significant decrease in the quality of life of patients, and is a major risk factor for esophageal adenocarcinoma. Nowadays, antisecretory therapy with proton pump inhibitors (PPI) is the "gold standard" of conservative treatment of GERD, but in some cases this therapy is unsuccessful. According to various studies, the prevalence of refractory GERD can reach 30-40%. The latest scientific data in the field of genetics and pathophysiology of GERD demonstrate that a disruption of the barrier function of the esophageal mucosa and an increase of its permeability can be the leading causes of refractoriness. Thus, the optimal therapy for patients with GERD should not only suppress the secretion of hydrochloric acid, but also restore the barrier function of the mucous membrane, providing an esophagoprotective effect. To achieve these goals, Alfasoxx was developed, which consists of a mixture of low molecular weight hyaluronic acid and low molecular weight chondroitin sulfate dissolved in a bioadhesive carrier (poloxamer 407). The clinical efficacy of this product has been confirmed by three prospective, randomized, placebo - controlled trials. Alfasoxx has a healing and restorative effect towards the esophageal epithelium and due to high ability for bioadhesion provides long - term protection of the mucous membrane of the esophagus. Combination therapy for GERD with the use of PPI and an esophagoprotector offers new perspectives for the treatment of patients with GERD.

Solute carrier family 9, subfamily A, member 3 (SLC9A3)/sodium-hydrogen exchanger member 3 (NHE3) dysregulation and dilated intercellular spaces in patients with eosinophilic esophagitis

BACKGROUND

Eosinophilic esophagitis (EoE) is characterized by histopathologic modifications of esophageal tissue, including eosinophil-rich inflammation, basal zone hyperplasia, and dilated intercellular spaces (DIS). The underlying molecular processes that drive the histopathologic features of EoE remain largely unexplored.

OBJECTIVE

We sought to investigate the involvement of solute carrier family 9, subfamily A, member 3 (SLC9A3) in esophageal epithelial intracellular pH (pHi) and DIS formation and the histopathologic features of EoE.

METHODS

We examined expression of esophageal epithelial gene networks associated with regulation of pHi in the EoE transcriptome of primary esophageal epithelial cells and an in vitro esophageal epithelial 3-dimensional model system (EPC2-ALI). Molecular and cellular analyses and ion transport assays were used to evaluate the expression and function of SLC9A3.

RESULTS

We identified altered expression of gene networks associated with regulation of pHi and acid-protective mechanisms in esophageal biopsy specimens from pediatric patients with EoE (healthy subjects, n = 6; patients with EoE, n = 10). The most dysregulated gene central to regulating pHi was SLC9A3. SLC9A3 expression was increased within the basal layer of esophageal biopsy specimens from patients with EoE, and expression positively correlated with disease severity (eosinophils/high-power field) and DIS (healthy subjects, n = 10; patients with EoE, n = 10). Analyses of esophageal epithelial cells revealed IL-13-induced, signal transducer and activator of transcription 6-dependent SLC9A3 expression and Na+-dependent proton secretion and that SLC9A3 activity correlated positively with DIS formation. Finally, we showed that IL-13-mediated, Na+-dependent proton secretion was the primary intracellular acid-protective mechanism within the esophageal epithelium and that blockade of SLC9A3 transport abrogated IL-13-induced DIS formation.

CONCLUSIONS

SLC9A3 plays a functional role in DIS formation, and pharmacologic interventions targeting SLC9A3 function may suppress the histopathologic manifestations in patients with EoE.

The Esophageal Epithelial Barrier in Health and Disease

Dysfunction in the esophageal epithelial barrier function is a major source for morbidity. To better understand the pathophysiologic pathways of the diseases associated with barrier dysfunction, including gastroesophageal reflux disease, eosinophilic esophagitis, Barrett's esophagus, and obesity, it is important to understand the esophageal epithelial embryologic development, microscopic anatomy with a special focus on the barrier structure and function, extraepithelial defense mechanisms, and how these change in the diseased state. In recent years, significant progress has been made in elucidating the esophageal barrier structure and function both in vitro and in vivo. This has enhanced the understanding of mechanisms of disease, and may also allow identification of therapeutic targets that can help in the management of these diseases. This review provides a detailed discussion regarding the esophageal epithelial barrier structure and function, the current and historical techniques used to study the barrier, and how it is affected by common esophageal diseases.

Lack of correlation between gastroesophageal reflux disease symptoms and esophageal lesions after sleeve gastrectomy

BACKGROUND

The postoperative development or worsening of gastroesophageal reflux disease (GERD) represents the major drawback of laparoscopic sleeve gastrectomy (SG). A GERD diagnosis is often based only on symptoms and proton pump inhibitors (PPI) intake, while objective tests like esophagogastroduodenoscopy and pH measurements are performed less frequently.

OBJECTIVES

To evaluate the association between reflux symptoms and GERD-related esophageal lesions.

SETTINGS

University hospital, Rome, Italy.

METHODS

A comprehensive clinical control entailing GERD symptoms, PPI intake, and esophagogastroduodenoscopy was proposed to all patients who underwent SG between June 2007 and February 2011, irrespective of the presence of GERD symptoms. One hundred forty-four of 219 patients agreed to take part in the study (follow-up rate: 65.8%).

RESULTS

After a mean follow-up of 66 months, GERD symptoms and PPI intake were recorded in 70.2% and 63.9% of patients, respectively. Mean visual analogue scale score was 2.9 ± 3.3. The overall frequency of erosive esophagitis was 59.8%, while nondysplastic Barrett's esophagus was detected in 13.1%. The frequency of esophageal biliary reflux was 68%. GERD symptoms and visual analogue scale score were not significantly associated with the development of erosive esophagitis and Barrett's esophagus and the severity of the esophageal lesions. Moreover, the frequency of erosive esophagitis and Barrett's esophagus in patients consuming PPI were similar to that of patients without PPI.

CONCLUSION

Symptoms investigation alone is not a reliable tool to diagnose GERD after SG. The use of objective diagnostic tests, such as esophagogastroduodenoscopy, should be carefully considered in the postoperative follow-up schedule of SG patients.

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.

Baseline impedance measured during high-resolution esophageal impedance manometry reliably discriminates GERD patients

BACKGROUND

Baseline impedance measured with ambulatory impedance pH monitoring (MII-pH) and a mucosal impedance catheter detects gastroesophageal reflux disease (GERD). However, these tools are limited by cost or patient tolerance. We investigated whether baseline impedance measured during high-resolution impedance manometry (HRIM) distinguishes GERD patients from controls.

METHODS

Consecutive patients with clinical HRIM and MII-pH testing were identified. Gastroesophageal reflux disease was defined by esophageal pH <4 for ≥5% of both the supine and total study time, whereas controls had an esophageal pH <4 for ≤3% of the study performed off PPI. Baseline impedance was measured over 15 seconds during the landmark period of HRIM and over three 10 minute intervals during the overnight period of MII-pH.

KEY RESULTS

Among 29 GERD patients and 26 controls, GERD patients had a mean esophageal acid exposure time of 22.7% compared to 1.2% in controls (P<.0001). Mean baseline impedance during HRIM was lower in GERD (1061 Ω) than controls (2814 Ω) (P<.0001). Baseline mucosal impedance measured during HRIM and MII-pH correlated (r=0.59, P<.0001). High-resolution esophageal manometry baseline impedance had high diagnostic accuracy for GERD, with an area under the curve (AUC) of 0.931 on receiver operating characteristics (ROC) analysis. A HRIM baseline impedance threshold of 1582 Ω had a sensitivity of 86.2% and specificity of 88.5% for GERD, with a positive predictive value of 89.3% and negative predictive value of 85.2%.

CONCLUSIONS & INFERENCES

Baseline impedance measured during HRIM can reliably discriminate GERD patients with at least moderate esophageal acid exposure from controls. This diagnostic tool may represent an accurate, cost-effective, and less invasive test for GERD.

The Relationship of the Post-reflux Swallow-induced Peristaltic Wave Index and Esophageal Baseline Impedance with Gastroesophageal Reflux Disease Symptoms

Background/Aims

The post-reflux swallow-induced peristaltic wave (PSPW) index and esophageal baseline impedance (BI) are novel impedance parameters used to evaluate esophageal chemical clearance and mucosal integrity. However, their relationship with reflux symptoms is not known. We aim to evaluate the correlations of PSPW index and esophageal BI with gastroesophageal reflux disease (GERD) symptoms.

Methods

We performed a retrospective review of multichannel intraluminal impedance and pH (MII-pH) tracings in patients with suspected GERD. Reflux symptoms were also analyzed from checklists using ordinal scales. The PSPW index and esophageal BIs in 6 spots (z1–z6) were measured. Bivariate (Spearman) correlation was used to analyze the relationship between the PSPW index or esophageal BI, and the degree of GERD symptoms measured.

Results

The MII-pH records of 143 patients were analyzed. The PSPW index was significantly lower in patients who had heartburn and negatively correlated with the degree of heartburn (r = −0.186, P < 0.05). On the contrary, the PSPW index was not significantly correlated with the degree of dysphagia (r = −0.013, P = 0.874). Distal esophageal BI was not significantly correlated with heartburn, but negatively correlated with the degree of dysphagia (z3: r = −0.328, z4: r = −0.361, z5: r = −0.316, z6: r = −0.273; P < 0.05).

Conclusions

These findings suggest that delayed chemical clearance of the esophagus may induce heartburn, but that it is not related to dysphagia. However, a lack of esophageal mucosal integrity may be related to dysphagia.

Importance of diagnosis and management of psychological disorders in patients with refractory gastroesophageal reflux disease

Psychological factors are closely related to the pathogenesis of gastroesophageal reflux disease, irritable bowel syndrome, functional dyspepsia, and other gastrointestinal diseases. It has been widely accepted that psychological factors play a very important role in refractory gastroesophageal reflux disease (RGERD). This article reviews the role of psychological factors in the epidemiology, pathogenesis, assessment, and management of RGERD.

Esophageal Impedance Monitoring: Clinical Pearls and Pitfalls

The development of intraluminal esophageal impedance monitoring has improved our ability to detect and measure gastroesophageal reflux without dependence on acid content. This ability to detect previously unrecognized weak or nonacid reflux episodes has had important clinical implications in the diagnosis and management of gastroesophageal reflux disease (GERD). In addition, with the ability to assess bolus transit within the esophageal lumen, impedance monitoring has enhanced the recognition and characterization of esophageal motility disorders in patients with nonobstructive dysphagia. The assessment of the intraluminal movement of gas and liquid has also been proven to be of diagnostic value in conditions such as rumination syndrome and excessive belching. Further, alternative applications of impedance monitoring, such as the measurement of mucosal impedance, have provided novel insights into assessing esophageal mucosal integrity changes as a consequence of inflammatory change. Future applications for esophageal impedance monitoring also hold promise in esophageal conditions other than GERD. However, despite all of the clinical benefits afforded by esophageal impedance monitoring, important clinical and technical shortcomings limit its diagnostic value and must be considered when interpreting study results. Overinterpretation of studies or application of impedance monitoring in patients can have deleterious clinical implications. This review will highlight the clinical benefits and limitations of esophageal impedance monitoring and provide clinical pearls and pitfalls associated with this technology.

Bile Salts at Low pH Cause Dilation of Intercellular Spaces in In Vitro Stratified Primary Esophageal Cells, Possibly by Modulating Wnt Signaling

BACKGROUND

The presence of dilated intercellular spaces in the stratified squamous lining of the esophagus is the pathognomonic feature of reflux esophagitis secondary to gastroesophageal reflux disease (GERD). In addition to stomach acid, bile salts are major constituents of gastroesophageal refluxate. The aim of our study was to determine the effect of bile salts cocktail at different pHs on epithelial junctions in an in vitro transwell model of stratified esophageal squamous epithelium.

DISCUSSION

Human telomerase reverse transcriptase (hTERT) immortalized primary esophageal EPC1 cells were grown on polyester transwell surfaces in calcium-enriched media. The cells exhibited gradual stratification into an 11-layered squamous epithelium over 7 days, together with epithelial barrier function as indicated by increased transepithelial electrical resistance (TEER). This stratified epithelium demonstrated well-formed tight junctions, adherens junctions, and desmosomes as visualized by immunofluorescence and electron microscopy. When exposed to short pulses of bile salts at pH 5, but not either condition alone, there was loss of stratification and decrease in TEER, concomitant with disruption of adherens junctions, tight junctions, and desmosomes, leading to the appearance of dilated intercellular spaces. At the cellular level, bile salts at pH 5 activated the Wnt pathway (indicated by increased β-catenin Ser552 phosphorylation).

CONCLUSION

In conclusion, in our in vitro transwell model bile salts at pH 5, but not bile salts or media at pH 5 alone, modulate Wnt signaling, disrupt different junctional complexes, and cause increased permeability of stratified squamous esophageal epithelium. These changes approximate the appearance of dilated intercellular space similar to that found in GERD patients.

Influence of reflux and central obesity on intercellular space diameter of esophageal squamous epithelium

BACKGROUND

While central obesity increases gastroesophageal reflux (GER) by mechanically disrupting the anti-reflux barrier, limited data exist on pathways by which central obesity may potentiate esophageal injury by non-mechanical means. Obesity has been associated with an impaired epithelial intestinal barrier.

OBJECTIVE

We aimed to assess the influence of central obesity and reflux on the squamous esophageal epithelial intercellular space diameter (ICSD).

METHODS

The ICSD was measured using electron microscopy in esophageal biopsies from individuals who underwent ambulatory pH monitoring and endoscopy. Anthropometric measurements were obtained on all participants. Participants were classified into four groups: with and without central obesity and reflux.

RESULTS

Sixteen individuals were studied with four in each study group. The mean ICSD was almost three-fold greater (p < 0.001) in the group with central obesity without reflux, compared to controls without central obesity and reflux. It was also comparable to the ICSD in groups with acid reflux only and those with both reflux and central obesity.

CONCLUSIONS

There is evidence of esophageal squamous ICSD increase in individuals with central obesity who do not have evidence of acid and nonacid reflux on ambulatory pH monitoring. This may reflect a mechanism by which central obesity potentiates reflux-induced esophageal injury and inflammation.

The Nonsteroidal Anti-inflammatory Drug Diclofenac Reduces Acid-Induced Heartburn Symptoms in Healthy Volunteers

BACKGROUND & AIMS

We investigated the effects of diclofenac, a nonsteroidal anti-inflammatory drug that inhibits prostaglandin production, on induction of esophageal sensation by acid perfusion in healthy men.

METHODS

We performed a prospective, double-blind, placebo-controlled, 2-period, cross-over study over 3 visits in 12 healthy men. Diclofenac was given 6 hours and 2 hours before an acid perfusion test. During the test, hydrochloric acid (0.15 mol/L) was perfused into the lower esophagus for 30 minutes; we evaluated upper gastrointestinal symptoms using a validated categoric rating scale. Then, we calculated and assessed the acid perfusion sensitivity score (APSS). Biopsy specimens were collected by endoscopy of the distal esophagus before and after acid perfusion; levels of prostaglandin E2 (PGE2) (pg/mg) were measured in the samples using an enzyme-linked immunosorbent assay.

RESULTS

Compared with placebo, diclofenac significantly reduced the APSS for heartburn (82.2 ± 12.2 for placebo and 47.5 ± 8.9 for diclofenac; P < .01). Of the upper gastrointestinal symptoms, only the APSS for heartburn was reduced significantly by diclofenac. Compared with placebo, diclofenac reduced the overproduction of PGE2 by esophageal tissues after acid perfusion (23.3 ± 5.2 for placebo and 11.4 ± 3.5 for diclofenac; P < .05). APSS correlated with the development of heartburn and esophageal levels of PGE2 (r = 0.53; P < .05 for heartburn vs PGE2).

CONCLUSIONS

Diclofenac attenuated acid-induced heartburn by inhibiting PGE2 overproduction in the esophagus. Esophageal PGE2 might be involved in producing heartburn symptoms. Clinical Trials Registry no: UMIN000014595.

Irsogladine maleate and rabeprazole in non-erosive reflux disease: A double-blind, placebo-controlled study

AIM: To evaluate the efficacy of adding irsogladine maleate (IM) to proton-pump inhibitor (PPI) therapy in non-erosive reflux disease (NERD) treatment.

METHODS: One hundred patients with NERD were recruited and randomized to receive rabeprazole plus IM (group I) or rabeprazole plus placebo (group P). The efficacy of the treatment was assessed using the Frequency Scale for the Symptoms of Gastroesophageal Reflux Disease (FSSG) and the short form (SF)-36 quality of life questionnaires after four weeks of treatment. We also assessed whether patients with NERD with minimal changes (grade M) had different responses to the therapies compared with patients who did not have minimal changes (grade N).

RESULTS: Group I and group P showed significant improvements in their FSSG scores after the treatment (from 17.9 ± 7.9 to 9.0 ± 7.6, and from 17.7 ± 7.3 to 11.2 ± 7.9, respectively, P = 0.0001), but there was no statistically significant difference between the FSSG scores in group I and those in group P. Subgroup analysis showed that significant improvements in the FSSG scores occurred in the patients in group I who had NERD grade N (modified Los Angeles classification) (7.8 ± 7.4 vs 12.5 ± 9.8, P = 0.041). The SF-36 scores for patients with NERD grade N who had received IM and rabeprazole were significantly improved in relation to their vitality and mental health scores.

CONCLUSION: The addition of IM to rabeprazole significantly improves gastroesophageal reflux disease symptoms and the quality of the lives of patients with NERD grade N.

A bama minipig model of laryngopharyngeal reflux and the change of laryngopharyngeal mucosal ultrastructure

Background/Aims

To establish an animal model of laryngopharyngeal reflux (LPR) and study the effect of LPR on the laryngopharyngeal mucosal ultrastructure.

Methods

Ten Bama minipigs were randomly divided into control group and stent group. Every pig underwent endoscope, and baseline pH was monitored for 4 hours at laryngopharynx and distal esophagus, then specimens from laryngopharyngeal mucosa were biopsied. For the control group, these procedures were repeated on the 14th day. In the stent group, a custom-designed esophageal stent suit was implanted into esophagus, laryngopharyngeal and distal esophageal pH monitoring lasted for 2 hours, then stent suit was removed 3 days later. At last, the same procedures were done as the control group on the 14th day. Specimens were observed under transmission electron microscope to measure the intercellular space and desmosome number.

Results

In the control group, there was no laryngopharyngeal reflux on the first day and 14th day. Before the stent was implanted, there was also no laryngopharyngeal reflux in the stent group. In both 2 hours and 14 days after stent implantation, the num -ber of reflux, reflux time, and percentage time of pH < 4.0 were significantly increased (P < 0.05) in the stent group. There was no difference in intercellular space and desmosomes in the control group between baseline and 14th day. In the stent group, intercellular space of laryngopharyngeal mucosa was significantly increased (0.37 μm vs 0.96 μm, P = 0.008), and the number of desmosomes was significantly decreased (20.25 vs 9.5, P = 0.003).

Conclusions

A Bama minipig model of LPR was established by implanting a custom-designed stent suit. LPR might destroy the laryngophar yngeal mucosal barrier.

Mast cell activation is involved in stress-induced epithelial barrier dysfunction in the esophagus

OBJECTIVE

We aimed to investigate the role of mast cell in stress-induced barrier dysfunction in the esophagus and its possible pathway involved using mast cell-deficient (Ws/Ws) rats.

METHODS

Ws/Ws rats and normal (+/+) rats were submitted to chronic restraint stress (CRS) 2 h/day for 7 days. Tissues were obtained from distal esophagus. Mast cells were counted under Alcian blue-safranin O stain. Activation of mast cells was assessed using transmission electron microscope. Esophageal epithelial barrier dysfunction was evaluated by measuring intercellular spaces (ICS) and by quantifying tight junction (TJ) proteins. The localization and expression of mast cell-derived tryptase and proteinase activated receptor 2 (PAR-2) were assessed.

RESULTS

A higher number of mast cells and higher proportion of activated mast cells were observed in CRS +/+ rats compared with non-stress controls. Increased ICS and decreased expression of some TJ proteins were observed in the CRS +/+ rats but not in the CRS Ws/Ws rats. Tryptase and its receptor PAR-2 were found elevated concomitantly by nearly 100% in CRS +/+ rats, but not in CRS Ws/Ws rats.

CONCLUSIONS

Mast cells play an important role in stress-induced epithelial barrier dysfunction in esophagus. The mechanism may involve the activation of PAR-2 by mast cell-derived tryptase, causing proinflammatory responses and the subsequent disruption of the epithelial TJ proteins and a disturbed cytoskeleton function, resulting in dilated intercellular spaces.

Gastroesophageal reflux in young children and adolescents: Is there a relation between symptom severity and esophageal histological grade?

BACKGROUND

The pediatric literature about the correlation between symptoms and histological lesions in patients investigated for gastroesophageal reflux disease is scarce and inconclusive. The primary aim of the present study was to assess the relation between the complained symptom severity and the esophageal histological grade, through the use of validated and reliable scores.

METHODS

All children ages between 2 and 17 years referred to perform upper gastrointestinal endoscopy because of gastroesophageal reflux disease symptoms were asked to complete the Pediatric Gastroesophageal Symptom and Quality of Life validated questionnaire, investigating the main symptoms complained and their impact on daily life and school activities. Esophageal mucosal samples taken during the procedure were analyzed and scored according to the Yerian-Fiocca classification.

RESULTS

A total of 164 children were included in the study. No significant association was found between symptomatic score and histological score (r(s): 0.05, P: 0.49). Even when focusing only on adolescents with heartburn or chest pain, no correlation between symptom severity and esophageal lesions was found (r(s): -0.18, P: 0.264). Intercellular space diameter values did not mirror symptom severity.

CONCLUSIONS

The main finding of this study on children with reflux symptoms is the lack of correlation between symptom severity and esophageal histological grade. The magnitude of intercellular spaces was found not to be related with the clinical score as well.

Comparison of light and electron microscopy in measurement of esophageal intercellular space in children

OBJECTIVES

A good objective marker of esophageal mucosal damage from gastroesophageal reflux disease (GERD) is lacking in children. Increased esophageal epithelial intercellular (EEIC) space measured using electron microscopy (EM) has been proposed as a surrogate of esophageal mucosal damage in adults with GERD. The aim of the present study was to compare EEIC space measured using EM and light microscopy (LM) in children with nonerosive reflux disease (NERD) with asymptomatic controls.

METHODS

Distal esophageal mucosal biopsy was used to measure EEIC space using EM in 35 NERD subjects and 8 controls. In a subset of these patients we used phase contrast LM to measure EEIC space area (26 NERD subjects and 8 controls).

RESULTS

The median (range) EEIC space measured using EM in the NERD group was 1.15 (0.74-1.64) μm compared with 0.93 (0.67-1.11) μm in the control group (P = 0.002). The median (range) EEIC space measured using LM was 14.4% (9.6%-26.3%) in the NERD group and 9.6% (8.5%-17.2%) in controls (P = 0.003). Using a cutoff value of 1.02 μm for normal EEIC space measured by EM, we obtained 73% sensitivity and 75% specificity to distinguish the NERD group from the control group, and using a cutoff value of 11.1% for EEIC space measured by LM, we obtained 96% sensitivity and 75% specificity.

CONCLUSIONS

EEIC space is increased in children with NERD compared with that in controls, suggesting that changes in EEIC space can be a useful marker of esophageal mucosal injury in children with NERD. Our results suggest that the accuracy of EM and LM to evaluate EEIC space changes in NERD is comparable, and LM may be a more cost-effective option.

Expression of claudin-3 in the esophagus and larynx of rat reflux model

OBJECTIVE

The aim of this study was to investigate the association between laryngeal expression of claudin-3 and laryngopharyngeal reflux (LPR) in a rat reflux model.

METHODS

Eight Wistar rats were divided into two groups. Four rats underwent total esophageal myectomy to induce reflux, and the remainder underwent a sham operation as a control. All animals were sacrificed 12 weeks after surgery to perform tissue histology and Western blot analysis.

RESULTS

Lymphocyte infiltration increased significantly in the study group in both esophageal and laryngeal samples (P=0.001, 0.002, respectively). Both esophageal and laryngeal expressions of claudin-3 were significantly lower in the study group when compared with that in the control group (P=0.045, 0.037, respectively).

CONCLUSION

The results of this study suggest that a decrease in claudin-3 could be a sensitive indicator of reflux laryngitis in rats.

Evidence for bladder urothelial pathophysiology in functional bladder disorders

Understanding of the role of urothelium in regulating bladder function is continuing to evolve. While the urothelium is thought to function primarily as a barrier for preventing injurious substances and microorganisms from gaining access to bladder stroma and upper urinary tract, studies indicate it may also function in cell signaling events relating to voiding function. This review highlights urothelial abnormalities in bladder pain syndrome/interstitial cystitis (BPS/IC), feline interstitial cystitis (FIC), and nonneurogenic idiopathic overactive bladder (OAB). These bladder conditions are typified by lower urinary tract symptoms including urinary frequency, urgency, urgency incontinence, nocturia, and bladder discomfort or pain. Urothelial tissues and cells from affected clinical subjects and asymptomatic controls have been compared for expression of proteins and mRNA. Animal models have also been used to probe urothelial responses to injuries of the urothelium, urethra, or central nervous system, and transgenic techniques are being used to test specific urothelial abnormalities on bladder function. BPS/IC, FIC, and OAB appear to share some common pathophysiology including increased purinergic, TRPV1, and muscarinic signaling, increased urothelial permeability, and aberrant urothelial differentiation. One challenge is to determine which of several abnormally regulated signaling pathways is most important for mediating bladder dysfunction in these syndromes, with a goal of treating these conditions by targeting specific pathophysiology.

Desmoglein-1 regulates esophageal epithelial barrier function and immune responses in eosinophilic esophagitis

The desmosomal cadherin desmoglein-1 (DSG1) is an essential intercellular adhesion molecule that is altered in various human cutaneous disorders; however, its regulation and function in allergic disease remains unexplored. Herein, we demonstrate a specific reduction in DSG1 in esophageal biopsies from patients with eosinophilic esophagitis (EoE), an emerging allergic disorder characterized by chronic inflammation within the esophageal mucosa. Further, we show that DSG1 gene silencing weakens esophageal epithelial integrity, and induces cell separation and impaired barrier function (IBF) despite high levels of desmoglein-3. Moreover, DSG1 deficiency induces transcriptional changes that partially overlap with the transcriptome of inflamed esophageal mucosa; notably, periostin (POSTN), a multipotent pro-inflammatory extracellular matrix molecule, is the top induced overlapping gene. We further demonstrate that IBF is a pathological feature in EoE, which can be partially induced through the downregulation of DSG1 by interleukin-13 (IL-13). Taken together, these data identify a functional role for DSG1 and its dysregulation by IL-13 in the pathophysiology of EoE and suggest that the loss of DSG1 may potentiate allergic inflammation through the induction of pro-inflammatory mediators such as POSTN.

A standardized method for measuring intercellular spaces in esophageal biopsies in patients with suspected gastroesophageal reflux disease (the intercellular space ratio)

OBJECTIVE

Dilated intercellular space (DIS) in esophageal biopsies is regarded as a possible early sign of mucosal injury in gastroesophageal reflux disease (GERD). This study presents a standardized approach of intercellular space measurement.

MATERIAL AND METHODS

Distal and proximal esophageal biopsies were taken from 19 patients with suspected GERD, and examined with TEM. A grid containing 150 line-crossing points was applied upon each photomicrograph. The number of points falling on the intercellular space was divided by the total number of points of the grid, thereby creating a ratio called the intercellular space ratio (ISR). The ISR method was validated with regard to intra- and interobserver agreement, and was compared to a widely used method for measuring intercellular space diameter developed by Tobey et al. (Tobey NA, Carson JL, Alkiek RA, Orlando RC. Dilated intercellular spaces: a morphological feature of acid reflux-damaged human esophageal epithelium. Gastroenterology 1996;111(5):1200-1205). The ISR was also compared to other markers for GERD. Results. Pearson's correlation coefficients for intra- and interobserver agreement were 0.91 (p < 0.001) and 0.82 (p < 0.001), respectively. The Pearson's correlation coefficient between the ISR and the intercellular space diameter according to Tobey et al., measured in the same micrographs, was 0.32 (p < 0.001). The proximal ISR correlated significantly with the distal ISR (Spearman's rho = 0.57, p = 0.010), and with heartburn symptom score (Spearman's rho = 0.50, p = 0.028).

CONCLUSIONS

The ISR showed a high intraobserver and interobserver agreement. It also displayed good external validity when compared to other markers for gastroesophageal reflux. A rather poor correlation was however found between the ISR and the intercellular space diameter measured as described by Tobey et al.

Pathophysiology of gastro-esophageal reflux disease: a role for mucosa integrity?

BACKGROUND

Gastro-esophageal reflux disease (GERD) is very prevalent and has a high burden on health security system costs. Nevertheless, pathophysiology is complex and not well-understood. Several mechanisms have been proposed: decreased salivation, impaired esophageal clearance, decreased lower esophageal sphincter pressure resting tone, presence of hiatal hernia, increased number of transient lower esophageal sphincter relaxations (TLESRs), increased acid, and pepsin secretion, pyloric incompetence provoking duodeno-gastro-esophageal reflux of bile acids and trypsin. Independent of the relevance of each mechanism, the ultimate phenomenon is that mucosal epithelium is exposed for a longer time to agents as acid and pepsin or is in contact to luminal agents not commonly present in gastric refluxate as trypsin or bile acids. This leads to a visible damage of the epithelium (erosive esophagitis -EE) or impairing mucosal integrity without any sign of macroscopic alteration as occurs in non-erosive reflux disease (NERD). Luminal factors are not the only responsible for such impairment; more recent data indicate that endogenous factors may also play a role.

PURPOSE

This review will update the most recent findings on the putative pathophysiological mechanisms and specially will focus on the role of esophageal mucosal integrity in GERD. Methodologies used for the evaluation of mucosal integrity, its relevance in EE and NERD, its involvement in symptoms perception and the effect of luminal and endogenous factors will be discussed.

Bile acid at low pH reduces squamous differentiation and activates EGFR signaling in esophageal squamous cells in 3-D culture

BACKGROUND

Barrett's esophagus is a preneoplastic metaplasia in which the normal squamous epithelium of the esophagus changes to an intestinal, columnar phenotype due to long-term gastro-esophageal reflux. The major components of this reflux are bile and stomach acid. Previous in vitro studies on the effect of bile and acid on esophageal cells have predominantly relied on transformed esophageal squamous cells or cancer cells grown in monolayer culture.

DISCUSSION

In this study, we expanded our previous work using an immortalized primary esophageal squamous cell line (EPC1). We demonstrate that EPC1 cells form a multi-layer, stratified epithelium when grown on polyester transwell filters in media supplemented with calcium. When exposed to short pulses of bile and pH 5, but not either condition alone, EPC1 cells demonstrate a reduction in stratification layers and reduced expression of squamous epithelium-specific genes. Bile at pH 5 also causes activation of epidermal growth factor receptor and down-stream pathways. Blocking epidermal growth factor receptor activation partially attenuates the effects of bile acid and pH 5. These results suggest that bile at low pH, but not bile or low pH alone, promotes loss of differentiation status of stratified squamous esophageal epithelium in vitro, possibly by initiating a mucosal repair response through epidermal growth factor activation.

Relevance of ultrastructural alterations of intercellular junction morphology in inflamed human esophagus

BACKGROUND/AIMS

Detailed characterization of the ultrastructural morphology of intercellular space in gastroesophageal reflux disease has not been fully studied. We aimed to investigate whether subtle alteration in intercellular space structure and tight junction proteins might differ among patients with gastroesophageal reflux disease.

METHODS

Esophageal biopsies at 5 cm above the gastroesophageal junction were obtained from 6 asymptomatic controls, 10 patients with reflux symptoms but without erosions, and 18 patients with erosions. The biopsies were morphologically evaluated by transmission electron microscopy, and by using immunohistochemistry for tight junction proteins (claudin-1 and claudin-2 proteins).

RESULTS

The expressions of tight junction proteins did not differ between asymptomatic controls and gastroesophageal reflux disease patients. In patients with gastroesophageal reflux disease, altered desmosomal junction morphology was only found in upper stratified squamous epithelium. Dilated intercellular space occurred only in upper stratified squamous epithelium and in patients with erosive esophagitis.

CONCLUSIONS

This study suggests that dilated intercellular space may not be uniformly present inside the esophageal mucosa and predominantly it is located in upper squamous epithelium. Presence of desmosomal junction alterations is associated with increased severity of gastroesophageal reflux disease. Besides dilated intercellular space, subtle changes in ultrastructural morphology of intercellular space allow better identification of inflamed esophageal mucosa relevant to acid reflux.

Histology of symptomatic gastroesophageal reflux disease: is it predictive of response to proton pump inhibitors?

BACKGROUND AND AIM

To examine the differences in esophageal histopathology between non-erosive reflux disease (NERD) and reflux esophagitis (RE), and to investigate whether baseline esophageal histopathology can predict the therapeutic response to proton pump inhibitors (PPIs).

METHOD

The subjects comprised 94 patients with NERD (n = 71) or mild RE (n = 23). Tissue was biopsied from 5 cm above the squamo-columnar junction (SCJ), and the degree or presence of nine histopathological markers was assessed. The patients were treated with rabeprazole (RPZ) 10 mg once daily for 4 weeks. If complete heartburn relief was not achieved, RPZ was increased to 10 mg twice daily for another 2 weeks, and then to 20 mg twice daily for another 2 weeks if heartburn remained.

RESULTS

Features of esophageal histopathology 5 cm above the SCJ differed between NERD and RE patients. The esophageal histopathology in patients unresponsive to RPZ was characterized by Protein Gene Product (PGP) 9.5 negativity in those with NERD, and intraepithelial bleeding in those with RE. In addition, the combination of dilated intercellular spaces (DIS) (+)/PGP 9.5 (-) was indicative of strong resistance to PPI therapy in NERD patients.

CONCLUSION

The therapeutic efficacy of PPI can be predicted from the features of biopsied esophageal tissue. Factors predictive of resistance to treatment with PPI are negativity for PGP 9.5 in NERD patients and intraepithelial bleeding in RE patients.

Esophageal intraluminal baseline impedance is associated with severity of acid reflux and epithelial structural abnormalities in patients with gastroesophageal reflux disease

BACKGROUND

The esophageal intraluminal baseline impedance may be used to evaluate the status of mucosa integrity. Esophageal acid exposure decreases the baseline impedance. We aimed to compare baseline impedance in patients with various reflux events and with different acid-related parameters, and investigate the relationships between epithelial histopathologic abnormalities and baseline impedance.

METHODS

A total of 229 GERD patients and 34 controls underwent 24-h multichannel intraluminal impedance and pH monitoring (MII-pH monitoring), gastroendoscopy, and completed a GERD questionnaire (GerdQ). We quantified epithelial intercellular spaces (ICSs) and expression of tight junction (TJ) proteins by histologic techniques.

RESULTS

Mean baseline values in reflux esophagitis (RE) (1752 ± 1018 Ω) and non-erosive reflux disease (NERD) (2640 ± 1143 Ω) were significantly lower than in controls (3360 ± 1258 Ω; p < 0.001 and p = 0.001, respectively). Among NERD subgroups, mean baselines in the acid reflux group (2510 ± 1239 Ω) and mixed acid/weakly acidic reflux group (2393 ± 1009 Ω) were much lower than in controls (3360 ± 1258 Ω; p = 0.020 and p < 0.001, respectively). The mean baseline in severe RE patients was significantly lower than in mild RE patients (LA-C/D vs. LA-A/B: 970 ± 505 Ω vs. 1921 ± 1024 Ω, p < 0.001). There was a significant negative correlation between baseline value and acid exposure time (AET) (r = -0.41, p < 0.001), and a weak but significant correlation (r = -0.20, p = 0.007) between baseline value and weakly AET. Negative correlations were observed between ICS and the baseline impedance (r = -0.637, p < 0.001) and claudin-1 and the baseline impedance (r = -0.648, p < 0.001).

CONCLUSIONS

Patients with dominant acid reflux events and with longer AET have low baseline impedance. Baseline values are correlated with esophageal mucosal histopathologic changes such as dilated ICS and TJ alteration.

Role of tight junction proteins in gastroesophageal reflux disease

BACKGROUND

Gastroesophageal reflux disease (GERD) is associated with impaired epithelial barrier function that is regulated by cell-cell contacts. The aim of the study was to investigate the expression pattern of selected components involved in the formation of tight junctions in relation to GERD.

METHODS

Eighty-four patients with GERD-related symptoms with endoscopic signs (erosive: n = 47) or without them (non-erosive: n = 37) as well as 26 patients lacking GERD-specific symptoms as controls were included. Endoscopic and histological characterization of esophagitis was performed according to the Los Angeles and adapted Ismeil-Beigi criteria, respectively. Mucosal biopsies from distal esophagus were taken for analysis by histopathology, immunohistochemistry and quantitative reverse-transcription polymerase chain reaction (RT-PCR) of five genes encoding tight junction components [Occludin, Claudin-1, -2, Zona occludens (ZO-1, -2)].

RESULTS

Histopathology confirmed GERD-specific alterations as dilated intercellular spaces in the esophageal mucosa of patients with GERD compared to controls (P < 0.05). Claudin-1 and -2 were 2- to 6-fold upregulation on transcript (P < 0.01) and in part on protein level (P < 0.015) in GERD, while subgroup analysis of revealed this upregulation for ERD only. In both erosive and non-erosive reflux disease, expression levels of Occludin and ZO-1,-2 were not significantly affected. Notably, the induced expression of both claudins did not correlate with histopathological parameters (basal cell hyperplasia, dilated intercellular spaces) in patients with GERD.

CONCLUSIONS

Taken together, the missing correlation between the expression of tight junction-related components and histomorphological GERD-specific alterations does not support a major role of the five proteins studied in the pathogenesis of GERD.

Relationship between baseline impedance levels and esophageal mucosal integrity in children with erosive and non-erosive reflux disease

BACKGROUND

Baseline impedance measurement has been reported to be related to esophageal acid exposure and hypothesized to be a marker of microscopic changes of the esophageal mucosa. Aims of the study were to establish whether any relationship existed between the magnitude of intercellular space diameter (ISD) of esophageal mucosa and baseline impedance levels in children with gastro-esophageal reflux disease (GERD), and to compare baseline impedance levels between children with non erosive (NERD) and erosive (ERD) reflux disease.

METHODS

Fifteen children (median age: 11.2 years) with NERD, and 11 with ERD (median age: 9.6 years) were prospectively studied. All patients underwent upper endoscopy. Biopsies were taken 2-3cm above the Z-line, and ISD was measured using transmission electron microscopy. All patients underwent impedance pH-monitoring, and baseline impedance levels were assessed in the most distal impedance channel.

KEY RESULTS

Mean (±SD) ISD did not differ between NERD (1.0±0.3μm) and ERD (1.1 ± 0.3 μm, ns). Considering all patients together, no correlation was found between distal baseline impedance and ISD (r: -0.15; ns). Conversely, negative correlations were found between distal baseline impedance and acid exposure time (r: -0.76; P<0.001), long-lasting reflux episodes (r: -0.78; P<0.001), acid reflux episodes (r: -0.62; P<0.001), and acid clearance time (r: -0.79; P<0.001). Distal baseline impedance was significantly lower in ERD [1455 (947-2338) Ω] than in NERD children [3065 (2253-3771) Ω; P<0.01].

CONCLUSIONS & INFERENCES

  In children with GERD baseline impedance levels are not useful in predicting reflux-induced ultrastructural changes in the esophageal mucosa, despite their ability to discriminate between NERD and ERD.