Dilated intercellular spaces as a marker of oesophageal damage: comparative results in gastro-oesophageal reflux disease with or without bile reflux

Pathophysiology of gastro-oesophageal reflux disease: implications for diagnosis and management

Gastro-oesophageal reflux disease (GERD) is a common gastrointestinal disorder in which retrograde flow of gastric content into the oesophagus causes uncomfortable symptoms and/or complications. It has a multifactorial and partially understood pathophysiology. GERD starts in the stomach, where the refluxate material is produced. Following the trajectory of reflux, the failure of the antireflux barrier, primarily the lower oesophageal sphincter and the crural diaphragm, enables the refluxate to reach the oesophageal lumen, triggering oesophageal or extra-oesophageal symptoms. Reflux clearance mechanisms such as primary and secondary peristalsis and the arrival of bicarbonate-rich saliva are critical to prevent mucosal damage. Alterations of the oesophageal mucosal integrity, such as macroscopic oesophagitis or microscopic changes, determine the perception of symptoms. The intensity of the symptoms is affected by peripheral and central neural and psychological mechanisms. In this Review, we describe an updated understanding of the complex and multifactorial pathophysiology of GERD. It is now recognized that different GERD phenotypes have different degrees of reflux, severity of mucosal integrity damage and type, and severity of symptoms. These variations are probably due to the occurrence of a predominant pathophysiological mechanism in each patient. We also describe the main pathophysiological mechanisms of GERD and their implications for personalized diagnosis and management.

Association between Mean Nocturnal Baseline Impedance (MNBI) and Post-Reflux Swallow-Induced Peristaltic Wave Index (PSPW) in GERD Patients

Gastroesophageal reflux disease (GERD) is one of the most common gastrointestinal disorders in the world. Two parameters, mean nocturnal baseline impedance (MNBI) and post-reflux swallow-induced peristaltic wave index (PSPW), have been recently proposed to help differentiate GERD phenotypes. Our study aimed to assess whether there is any correlation between the two parameters, while also taking a look at their ability to distinguish between GERD phenotypes. We recruited 81 patients who were divided into 4 groups based on their GERD phenotype: erosive reflux disease (ERD), non-erosive reflux disease (NERD), reflux hypersensitivity (RH), and functional heartburn (FH). Both MNBI (AUROC 0.855) and PSPW (AUROC 0.835) had very good performances in separating ERD patients from non-ERD patients. PSPW (AUROC 0.784) was superior to MNBI (AUROC 0.703) in distinguishing NERD patients from patients with RH or FH. The PSPW index (AUROC 0.762) was more effective than MNBI (AUROC 0.668) in separating RH from FH. We found that PSPW and MNBI have a strong statistical correlation (Pearson correlation coefficient, r = 0.722, p < 0.001). Furthermore, PSPW predicted pathological MNBI (<2292 Ω) with good performance (AUROC 0.807). MNBI and PSPW are useful in distinguishing GERD phenotypes, with a strong correlation between the two parameters.

Revisiting the Role of Esophageal Mucosal Dilated Intercellular Spaces in the Diagnosis and Pathophysiology of Heartburn

Background/Aims

Dilated intercellular spaces (DISs) facilitate the diffusion of noxious agents into the deep layers of the esophageal epithelium. The role of DIS in heartburn pathogenesis is still controversial. Therefore, we aim to reinvestigate DIS in an extensively evaluated group of patients and healthy controls (HCs).

Methods

We classified 149 subjects into the following groups: 15 HC, 58 mild erosive reflux disease (ERD), 17 severe ERD, 25 nonerosive reflux disease (NERD), 15 reflux hypersensitivity (RH), and 19 functional heartburn (FH). A total of 100 length measurements were performed for each patient's biopsy.

Results

The overall intercellular spaces (ISs) value of gastroesophageal reflux disease (GERD) patients was higher than that of HC (P = 0.020). In phenotypes, mild ERD (vs HC [P = 0.036], NERD [P = 0.004], RH [P = 0.014]) and severe ERD (vs HC [P = 0.002], NERD [P < 0.001], RH [P = 0.001], FH [P = 0.004]) showed significantly higher IS. There was no significant difference between the HC, NERD, RH, and FH groups. The 1.12 μm DIS cutoff value had 63.5% sensitivity and 66.7% specificity in the diagnosis of GERD. There was a weak correlation (r = 0.302) between the IS value and acid exposure time, and a weak correlation (r = -0.359) between the IS value and baseline impedance. A strong correlation was shown between acid exposure time and baseline impedance (r = -0.783).

Conclusions

Since the IS length measurement had better discrimination power only in erosive groups, it is not feasible to use in daily routine to discriminate other nonerosive phenotypes and FH. The role of DIS in heartburn in nonerosive patients should be reconsidered.

Quantifying cerebrospinal fluid dynamics: A review of human neuroimaging contributions to CSF physiology and neurodegenerative disease

Cerebrospinal fluid (CSF), predominantly produced in the ventricles and circulating throughout the brain and spinal cord, is a key protective mechanism of the central nervous system (CNS). Physical cushioning, nutrient delivery, metabolic waste, including protein clearance, are key functions of the CSF in humans. CSF volume and flow dynamics regulate intracranial pressure and are fundamental to diagnosing disorders including normal pressure hydrocephalus, intracranial hypotension, CSF leaks, and possibly Alzheimer's disease (AD). The ability of CSF to clear normal and pathological proteins, such as amyloid-beta (Aβ), tau, alpha synuclein and others, implicates it production, circulation, and composition, in many neuropathologies. Several neuroimaging modalities have been developed to probe CSF fluid dynamics and better relate CSF volume and flow to anatomy and clinical conditions. Approaches include 2-photon microscopic techniques, MRI (tracer-based, gadolinium contrast, endogenous phase-contrast), and dynamic positron emission tomography (PET) using existing approved radiotracers. Here, we discuss CSF flow neuroimaging, from animal models to recent clinical-research advances, summarizing current endeavors to quantify and map CSF flow with implications towards pathophysiology, new biomarkers, and treatments of neurological diseases.

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.

Pathophysiology and treatment options for gastroesophageal reflux disease: looking beyond acid

Gastroesophageal reflux disease (GERD) is a disorder due to the retrograde flow of refluxate into the esophagus. Although GERD is a common clinical diagnosis, its pathogenesis is quite complex. As a result of its multifactorial development, many patients continue to experience adverse symptoms due to GERD despite prolonged acid suppression with proton pump inhibitor therapy. The pathogenesis of GERD involves an interplay of chemical, mechanical, psychologic, and neurologic mechanisms, which contribute to symptom presentation, diagnosis, and treatment. As such, GERD should be approached as a disorder beyond acid. This review will investigate the major factors that contribute to the development of GERD, including factors related to the refluxate, esophageal defenses, and factors that promote pathologic reflux into the esophagus. In reviewing GERD pathogenesis, this paper will highlight therapeutic advances, with mention of future opportunities of study when approaching GERD.

Properties of a Novel Animal Model of LPR

BACKGROUND

Few satisfactory animal models of laryngopharyngeal reflux (LPR) is available. Interleukin-8 (IL-8) and vascular endothelial growth factor (VEGF) may be associated with the pathogenesis of LPR injuries and laryngeal carcinomas.

OBJECTIVES

To establish an animal model of LPR and to explore the related pathological changes and cytokine expression in the vocal cord tissue.

METHODS

Twenty rabbits were divided into experimental and control groups. Dilatation of the upper and lower esophageal sphincter were carried out in the experimental group. The pH of the pharynx, pathological, and ultrastructural changes of the laryngeal tissue, and expression of IL-8 and VEGF were compared between the experimental group and controls.

RESULTS

pH monitoring results and the dilated intercellular space of the vocal cord mucosa showed that the experimental group developed laryngopharyngeal reflux. There were significant differences in the immunohistochemical staining scores of both IL-8 (P = 0.015) and VEGF (P = 0.007) between the experimental and control groups in the vocal cord tissue.

CONCLUSIONS

We successfully established a model of LPR, showing histopathological and ultrastructural changes consistent with the disease. The expression of IL-8 and VEGF may increase during the pathogenesis of LPR.

A Prospective Study of Eosinophilic Esophagitis and the Expression of Tight Junction Proteins in Patients with Gastroesophageal Reflux Disease Symptoms

Background/Aims

Eosinophilic esophagitis (EoE) is often erroneously diagnosed as gastroesophageal reflux disease (GERD). The aim of this study is to investigate the prevalence of EoE and the expression of tight junction (TJ) proteins in patients with GERD symptoms.

Methods

One hundred patients with GERD symptoms and 10 healthy controls were prospectively studied. Sixty-two patients had symptoms refractory to proton pump inhibitors (PPI). All patients underwent esophageal biopsy. Patients were diagnosed with EoE if the number of eosinophil granulocytes per high-power field was ≥15. Immunohistochemical analysis of TJ proteins (claudin-1, claudin-4, occludin, and zonula occludin-1 [ZO-1]) was performed.

Results

EoE was diagnosed in six of 100 patients (6%) with GERD symptoms and in six patients (9.7%) of 62 patients with PPI-refractory GERD. Only one had typical EoE endoscopic findings. The proportion of ZO-1-positive cells was significantly lower in the lower than in the middle esophagus (56.0%±14.0% vs 66.0%±11.5%, p＜0.05). There were no significant correlations between TJ protein expression and GERD symptoms.

Conclusions

The prevalence of EoE among patients with PPI-refractory GERD is approximately 10%. Regardless of endoscopic findings, esophageal biopsy is crucial in diagnosing EoE. The disruption of ZO-1 expression in the lower esophagus is significantly associated with GERD symptoms.

Mucosal Impedance: a New Approach to Diagnosing Gastroesophageal Reflux Disease and Eosinophilic Esophagitis

PURPOSE OF REVIEW

In this review, we discuss current diagnostic testing modalities for both gastroesophageal reflux disease (GERD) and eosinophilic esophagitis (EoE) and then introduce mucosal impedance (MI), a novel technology that measures epithelial integrity in real time during endoscopy. We describe the advantages and disadvantages of MI as compared with traditional diagnostic testing.

RECENT FINDINGS

We review studies that demonstrate that GERD and EoE have distinct MI patterns, and that physicians can accurately diagnose and distinguish the two during endoscopy with minimal time added to the procedure. We also review studies showing that MI has the capability to assess treatment response in both GERD and EoE and that it can be used to diagnose GERD in patients with extraesophageal reflux symptoms. Mucosal impedance testing is a major advancement in the diagnosis of GERD and EoE. Future studies are planned to assess whether MI can be used as a treatment endpoint in EoE and whether it can be used to predict response to anti-reflux surgery.

Fragments of e-Cadherin as Biomarkers of Non-erosive Reflux Disease

BACKGROUND

Approximately, 20% of patients with heartburn and normal endoscopic findings do not symptomatically improve on proton pump inhibitor (PPI) therapy making diagnosis and treatment uncertain. A biomarker distinguishing PPI-responsive from PPI-refractory heartburn is desirable.

AIMS

We performed a pilot study assessing whether carboxy(C)-terminal fragments (CTFs) of e-cadherin in esophageal biopsies or amino(N)-terminal fragments (NTFs) of e-cadherin in serum could serve this purpose.

METHODS

Twenty-nine patients with endoscopy-negative heartburn had esophageal biopsies for CTFs on Western blot and blood for serum NTFs on ELISA. All patients received dexlansoprazole 30 mg daily for 4 weeks, and heartburn was assessed by daily diary entry. Post-treatment blood samples were obtained for serum NTFs. A control group without GERD symptoms (n = 6) had biopsies for CTFs and a second control group (n = 20) blood serum for serum NTFs.

RESULTS

Twenty-seven of 29 patients (93.1%) with endoscopy-negative heartburn, but 0 of 6 controls, were positive for CTFs. All patients and controls had measureable serum NTFs, but mean NTFs were significantly higher in those with PPI-responsive heartburn compared to those with PPI-refractory heartburn and controls. Following treatment, 24 of 29 (82.8) patients had relief of heartburn, which associated with a decline in mean NTFs compared to controls. NTFs in PPI-refractory patients (n = 5) were similar to controls before and after PPI therapy.

CONCLUSIONS

When heartburn responds to PPI, elevated serum NTFs decline to normal. These data suggest that cleaved products of e-cadherin may serve as biomarkers of NERD. Further data are needed to assess and confirm this concept.

Esophageal Baseline Impedance Reflects Mucosal Integrity and Predicts Symptomatic Outcome With Proton Pump Inhibitor Treatment

Background/Aims

Esophageal baseline impedance, which is decreased in gastroesophageal reflux disease (GERD) patients, is related to the severity of acid reflux and the integrity of the esophageal mucosa. The study aims to compare the baseline impedance and the dilated intercellular spaces (DIS) within patients with typical reflux symptoms and to evaluate the correlation of baseline impedance with DIS, esophageal acid exposure, as well as the efficacy of proton pump inhibitor (PPI) treatment.

Methods

Ninety-two patients and 10 healthy controls were included in the study. Erosive esophagitis (EE) was defined by esophageal mucosal erosion under upper endoscopy. Patients without mucosa erosion were divided into groups with pathologic acid reflux (non-erosive reflux disease [NERD]) or with hypersensitive esophagus. The biopsies of esophageal mucosa were taken 2–4 cm above the gastroesophageal junction Z-line during upper endoscopy for DIS measurement. All the patients received esomeprazole 20 mg twice-daily treatment for 8 weeks. The efficacy of esomeprazole was evaluated among all patients.

Results

The intercellular spaces were dilated in both EE and NERD patients (P < 0.05). The value 0.73 μm could be used as the cut-off DIS value to distinguish patients from controls (area under the curve [AUC] = 0.849, P < 0.01). One thousand seven hundred sixty-four ohms could be used as the cut-off impedance values to distinguish patients from controls (AUC = 0.794, P < 0.01). The baseline impedance was decreased in both EE patients and NERD patients, and negatively correlated to the acid exposure time (r = −0.527, P < 0.05). There was a weak correlation between DIS and baseline impedance (r = −0.230, P < 0.05). “Baseline impedance > 1764 Ω” was an independent predictor for PPI failure (OR, 11.9; 95% CI, 2.4–58.9; P < 0.01).

Conclusions

The DIS and decreased baseline impedance was observed in patients with mucosa erosion or pathological acid reflux. The baseline impedance reflected the mucosal integrity, it was more sensitive to esophageal acid exposure. Patients with high impedance might not benefit from the PPI treatment.

Diagnosis of gastro-oesophageal reflux disease is enhanced by adding oesophageal histology and excluding epigastric pain

BACKGROUND

The diagnosis of gastro-oesophageal reflux disease (GERD) in clinical practice is limited by the sensitivity and specificity of symptoms and diagnostic testing.

AIM

To determine if adding histology as a criterion and excluding patients with epigastric pain enhances the diagnosis for GERD.

METHODS

Patients with frequent upper gastrointestinal symptoms who had not taken a proton pump inhibitor in the previous 2 months and who had evaluable distal oesophageal biopsies were included (Diamond study: NCT00291746). Epithelial hyperplasia was identified when total epithelial thickness was at least 430 μm. Investigation-based GERD criteria were: presence of erosive oesophagitis, pathological oesophageal acid exposure and/or positive symptom-acid association probability. Symptoms were assessed using the Reflux Disease Questionnaire and a pre-specified checklist.

RESULTS

Overall, 127 (55%) of the 231 included patients met investigation-based GERD criteria and 195 (84%) met symptom-based criteria. Epithelial hyperplasia was present in 89 individuals, of whom 61 (69%) met investigation-based criteria and 83 (93%) met symptom-based criteria. Adding epithelial hyperplasia as a criterion increased the number of patients diagnosed with GERD on investigation by 28 [12%; number needed to diagnose (NND): 8], to 155 (67%). The proportion of patients with a symptom-based GERD diagnosis who met investigation-based criteria including epithelial hyperplasia was significantly greater when concomitant epigastric pain was absent than when it was present (P < 0.05; NND: 8).

CONCLUSIONS

Histology increases diagnosis of GERD and should be performed when clinical suspicion is high and endoscopy is negative. Excluding patients with epigastric pain enhances sensitivity for the diagnosis of GERD.

Ambulatory 24-hour multichannel intraluminal impedance-pH monitoring and high resolution endoscopy distinguish patients with non-erosive reflux disease from those with functional heartburn

AIMS

To assess the contribution of 24-h esophageal multichannel intraluminal impedance and pH (MII-pH) monitoring and high resolution endoscopy (HRE) with i-scan imaging in differentiating non erosive reflux disease (NERD) from functional heartburn (FH).

METHODS

This is a retrospective cohort study of patients with heartburn from the Endoscopy Unit. NERD patients and FH patients were defined by 24-h MII-pH monitoring and white light endoscopy. Minimal mucosal changes were assessed by HRE with i-scan imaging.

RESULTS

Total of 156 consecutive patients with heartburn but without esophageal mucosal erosions were studied. Forty-eight of these subjects had NERD, with increased acid exposure time (AET) and positive SAP and/or SI. Eighteen had FH with normal AET and negative SAP and SI. When compared to FH patients and healthy controls, NERD patients had significantly increased number of total acid reflux episodes, as well as increased number of weakly acidic reflux episodes (p<0.01). The rate of proximal reflux episodes in NERD patients was higher than that of FH patients and healthy controls (p<0.01). Irregular or blurring of the Z-line (58.3%) and white mucosal turbidity (47.9%) were the most common endoscopic findings of minimal mucosal changes observed in this study. NERD patients had more prevalent minimal changes than FH patients and the controls (87.5%vs. 66.6%vs. 61.9%; p = 0.004) with sensitivity of 87.5%. Histopathological evaluation showed that NERD patients had significantly higher average scores of intercellular spaces dilation (2.82±0.9 vs. 1.2±0.6, p = 0.005) and papillae elongation (2.65±1.0 vs. 1.5±0.8, p = 0.014), but not for basal cell proliferation (1.6±1.3 vs. 1.0±0.9, p = 0.070). The histological scores of the NERD patients were 7.1±1.2, which were higher than those of FH patients (3.4±1.0, p = 0.004).

CONCLUSIONS

Minimal mucosal changes could be useful markers to support clinical diagnosis of NERD. Combination of 24-h MII-pH monitoring and i-scan high resolution endoscopy can distinguish patients with NERD from those with FH.

Epithelial Thickness is a Marker of Gastroesophageal Reflux Disease

BACKGROUND & AIMS

Histologic criteria have been refined for the diagnosis of gastroesophageal reflux disease (GERD). We aimed to evaluate these criteria for the assessment of GERD and to measure interassessor agreement.

METHODS

We performed a post hoc analysis of data from the Diamond study (NCT 00291746), conducted in Europe and Canada on adults with frequent upper gastrointestinal symptoms who had not taken a proton pump inhibitor in the previous 2 months. GERD was diagnosed based on the presence of 1 or more of the following: reflux esophagitis, pathologic esophageal acid exposure, and/or positive symptom-acid association probability. Nonerosive reflux disease was defined as the presence of pathologic esophageal acid exposure and/or a positive symptom-acid association probability, but no reflux esophagitis. Biopsies collected from 336 patients from 0.5 cm and 2.0 cm above the Z line were evaluable; they were analyzed independently at pathology centers in Germany and Italy (biopsies from 258 and 195 patients, respectively). The primary outcomes were the accuracy of histologic criteria for the diagnosis of GERD, defined by endoscopy and pH monitoring, and interassessor agreement on histologic criteria.

RESULTS

At the assessment site for basal cell layer thickness, total epithelial thickness was the best-performing criterion for diagnosis of investigation-defined GERD; it also identified nonerosive reflux disease, reflux esophagitis, and pathologic esophageal acid exposure at 0.5 cm and 2.0 cm above the Z line. Basal cell layer thickness and presence of dilated intercellular spaces did not identify patients with GERD. Among the criteria tested, the best agreement between assessments carried out at the 2 pathology centers was for total epithelial thickness at 0.5 cm and 2.0 cm above the Z line.

CONCLUSIONS

Based on an analysis of 336 patients with frequent upper gastrointestinal symptoms, total epithelial thickness is a robust histologic marker for GERD.

Biomarkers of Reflux Disease

Gastroesophageal reflux disease (GERD) encompasses an array of disorders unified by the reflux of gastric contents. Because there are many potential disease manifestations, esophageal and extraesophageal, there is no single biomarker of the entire disease spectrum; a set of GERD biomarkers that each quantifies specific aspects of GERD-related pathology might be needed. We review recent reports of biomarkers of GERD, specifically in relation to endoscopically negative esophageal disease and excluding conventional pH-impedance monitoring. We consider histopathologic biomarkers, baseline impedance, and serologic assays to determine that most markers are based on manifestations of impaired esophageal mucosal integrity, which is based on increased ionic and molecular permeability, and/or destruction of tight junctions. Impaired mucosal integrity quantified by baseline mucosal impedance, proteolytic fragments of junctional proteins, or histopathologic features has emerged as a promising GERD biomarker.

Estrogen Enhances Esophageal Barrier Function by Potentiating Occludin Expression

BACKGROUND

We recently demonstrated that a female sex hormone, estrogen, suppressed esophageal epithelial injury in a reflux esophagitis model of rat, suggesting that estrogen may play an important role in controlling the progress of the gastro-esophageal reflux disease spectrum. However, the precise mechanism of the action is unclear.

AIM

To investigate the potential role of estrogen in the esophageal barrier function.

METHODS

Male rabbits were pretreated with either continuous release 17β-estradiol or placebo, and the excised esophageal mucosa was subjected to Ussing chamber experiments after the 2-week pre-treatment. The mucosal side of the chamber was perfused with luminal irritants (HCl or acidified sodium nitrite), while the basal side was perfused by modified Krebs buffer. The epithelial barrier function was evaluated by the transmembrane resistance and the epithelial permeability. The intercellular space of the epithelium was investigated with transmission electron microscopy and the expression of tight junction protein, occludin, claudin-1, and claudin-4, with immunoblotting.

RESULTS

Estrogen pre-treatment significantly attenuated the decrease in the transmembrane resistance and the increase in the epithelial permeability induced by luminal irritants. Furthermore, the dilation of the intercellular space induced by luminal HCl was significantly alleviated by 17β-estradiol administration. The baseline occludin expression was significantly potentiated by 17β-estradiol administration.

CONCLUSIONS

This is the first study showing an enhancement of the esophageal barrier function by 17β-estradiol administration. The lack of the protective effect of estrogen could be responsible for the male predominance of erosive reflux esophagitis.

Distinguishing GERD from eosinophilic oesophagitis: concepts and controversies

Over the past three decades, the detection of oesophageal mucosal eosinophils has transitioned from a biomarker of GERD to a diagnostic criterion for eosinophilic oesophagitis (EoE). In GERD, oesophageal eosinophils are considered part of the chronic inflammatory response to acid reflux, whereas the marked eosinophilia in EoE is viewed as a central feature of the immune response to ingested food and/or environmental antigen stimulation. Descriptions of a considerable subset of patients with symptomatic, endoscopic and histological findings of EoE that resolve with PPI therapy has led to confusion and controversy regarding the distinction of EoE from GERD. Study findings indicate that PPI-responsive oesophageal eosinophilia (PPI-REE) more closely resembles EoE than GERD, both from a clinical and immunological aspect. Although responsiveness to PPI therapy should not be utilized to exclude EoE, PPI therapy is effective at reducing oesophageal eosinophilia in ∼40% of patients, and PPI therapy is both a safe and practical initial step in the management of patients with oesophageal eosinophilia. Ongoing studies elucidating the mechanism behind PPI-REE will improve our understanding and management of EoE. In this Review, the mechanisms and evidence that underlie the controversy in the distinction between GERD and EoE are evaluated.

Mucosal impedance discriminates GERD from non-GERD conditions

BACKGROUND & AIMS

Current diagnostic tests for gastroesophageal reflux disease (GERD) are suboptimal and do not accurately and reliably measure chronicity of reflux. A minimally invasive device has been developed to assess esophageal mucosal impedance (MI) as a marker of chronic reflux. We performed a prospective longitudinal study to investigate MI patterns in patients with GERD and common nonreflux conditions, to assess MI patterns before and after treatment with proton pump inhibitors and to compare the performance of MI and wireless pH tests.

METHODS

We evaluated MI in 61 patients with erosive esophagitis, 81 with nonerosive but pH-abnormal GERD, 93 without GERD, 18 with achalasia, and 15 with eosinophilic esophagitis. MI was measured at the site of esophagitis and at 2, 5, and 10 cm above the squamocolumnar junction in all participants. MI was measured before and after acid suppressive therapy, and findings were compared with those from wireless pH monitoring.

RESULTS

MI values were significantly lower in patients with GERD (erosive esophagitis or nonerosive but pH-abnormal GERD) or eosinophilic esophagitis than in patients without GERD or patients with achalasia (P < .001). The pattern of MI in patients with GERD differed from that in patients without GERD or patients with eosinophilic esophagitis; patients with GERD had low MI closer to the squamocolumnar junction, and values increased axially along the esophagus. These patterns normalized with acid suppressive therapy. MI patterns identified patients with esophagitis with higher levels of specificity (95%) and positive predictive values (96%) than wireless pH monitoring (64% and 40%, respectively).

CONCLUSIONS

Based on a prospective study using a prototype device, measurements of MI detect GERD with higher levels of specificity and positive predictive values than wireless pH monitoring. Clinical Trials.gov, Number: NCT01556919.

Diagnostic value of dilated intercellular space and histopathologic scores in gastroesophageal reflux disease

The aim of this paper is to investigate the diagnostic value of histopathologic score and the dilated intercellular space (DIS) in patients with gastroesophageal reflux disease (GERD) and functional heartburn (FH). Participants with GERD symptoms including reflux esophagitis, non-erosive reflux disease (NERD), Barrett's esophagus (BE), functional heartburn (FH), along with a control group with atypical GERD-like symptom (Sym-C), and asymptomatic healthy volunteers (H-C) were administered GERD questionnaire, and subjected to endoscopy and biopsies, as well as 24-hour pH-impedance monitoring. Biopsies were evaluated using standards from the 2011 Esohisto Project after Hematoxylin-Eosin staining. DIS was measured quantitatively under light microscopy. Among the total of 565 participants with qualified biopsy specimens, the mean DIS of the reflux esophagitis (RE) group was significantly wider compared with the other five groups. DIS in patients with GERD-like symptoms was significantly wider compared with the H-C. No significant differences were observed between NERD and FH. Results from 24-hour pH-impedance monitoring indicated that only the DIS of patients with acid reflux or the amount of acid reflux episodes in patients with DIS was significantly wider compared with patients with nonacid reflux or patients without DIS (P < 0.001). With DIS = 0.9 μm as the cutoff value, the sensitivity and specificity were 62.6% and 54.1%, respectively. Using the total histopathologic score > 3 as the diagnostic criterion, the sensitivity and specificity were 71.7% and 47.4%. DIS is closely associated with GERD and acid reflux. The diagnostic value of histological scores in lower esophagus in GERD is very similar to that of the quantitative measurement of DIS.

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.

Pathophysiology of gastroesophageal reflux disease

Gastroesophageal reflux disease (GERD) is one of the most common digestive diseases in the Western world, with typical symptoms, such as heartburn, regurgitation, or retrosternal pain, reported by 15% to 20% of the general population. The pathophysiology of GERD is multifactorial. Our understanding of these factors has significantly improved in recent years, with increased understanding of the acid pocket and hiatal hernia and how these factors interact. Although our insight has significantly increased over the past years, more studies are required to better understand symptom generation in GERD, especially in patients with therapy-resistant symptoms.

Validation study of the Esohisto consensus guidelines for the recognition of microscopic esophagitis (histoGERD Trial)

In patients with gastroesophageal reflux disease (GERD), histology is generally believed to be a tool of limited diagnostic value. Our study aimed to assess the prevalence of microscopic esophageal lesions as defined by the Esohisto consensus guidelines, which have proven high interobserver agreement in previous studies. In the prospective Central European multicenter histoGERD trial, we recruited 1071 individuals (576 females and 495 males; median age, 53 years; range, 15-93 years) undergoing gastroscopy for nonselected reasons. Biopsy material was systematically sampled from above and below the gastroesophageal junction. Overall, histologic diagnosis of mild and severe esophagitis was made in 423 (39.5%) and 296 (27.6%) individuals, respectively, whereas the squamous mucosa of 352 individuals (32.9%) was normal upon histology or showed only insignificant findings. Proliferative changes of the squamous epithelium, in particular basal cell layer hyperplasia, papillary elongation, and intercellular space dilation, were more common than inflammatory cell infiltration. The presence of microscopic esophagitis was associated with male sex (P = .009), patients' symptoms (P = .003), history of proton pump inhibitor intake (P < .001), and the endoscopic diagnosis of esophagitis (P < .001). Notably, among the 450 patients with no endoscopic signs of esophagitis (Los Angeles Category N), 41.8% and 17.1% were identified with mild and severe (microscopic) esophagitis, respectively, indicating higher sensitivity of histologic diagnosis. In conclusion, our data illustrate the value of histology in the workup of patients with reflux disease. We suggest that biopsies should routinely be obtained when patients undergo upper gastrointestinal endoscopy for evaluation of GERD and may particularly be beneficial in patients with nonerosive reflux disease.

Endotherapy for and tailored approaches to treating GERD, and refractory GERD

This paper presents commentaries on how endoluminal antireflux procedures compare to laparoscopic fundoplication; new endoscopic procedures being studied to treat refractory gastroesophageal reflux disease (GERD); the new Stretta; the relationship between obesity and proton pump inhibitor (PPI) resistance; data concerning acid hypersensitivity and sensory receptors (vallinoid, TRPV1) causing refractory GERD; whether microscopic esophagitis is relevant in determining symptoms of non-erosive reflux disease (NERD); how concomitant functional gastrointestinal disorders affect the PPI response in NERD; the evidence that a functional esophagus is associated with inflammatory bowel syndrome (IBS); the role of GABA agonists in the treatment of refractory GERD; the role of biofeedback and antidepressants in refractory GERD; and endoluminal fundoplication using the EsophyX device.

Investigation of relationships among gastroesophageal reflux disease subtypes using narrow band imaging magnifying endoscopy

AIM: To investigate the relationships among subtypes of gastroesophageal reflux disease (GERD) using narrow band imaging (NBI) magnifying endoscopy.

METHODS: A reflux disease questionnaire was used to screen 120 patients representing the three subtypes of GERD (n = 40 for each subtypes): nonerosive reflux disease (NERD), reflux esophagitis (RE) and Barrett’s esophagus (BE). NBI magnifying endoscopic procedure was performed on the patients as well as on 40 healthy controls. The demographic and clinical characteristics, and NBI magnifying endoscopic features, were recorded and compared among the groups. Targeted biopsy and histopathological examination were conducted if there were any abnormalities. SPSS 18.0 software was used for all statistical analysis.

RESULTS: Compared with healthy controls, a significantly higher proportion of GERD patients had increased number of intrapapillary capillary loops (IPCLs) (78.3% vs 20%, P < 0.05), presence of microerosions (41.7% vs 0%, P < 0.05), and a non-round pit pattern below the squamocolumnar junction (88.3% vs 30%, P < 0.05). The maximum (228 ± 4.8 vs 144 ± 4.7, P < 0.05), minimum (171 ± 3.8 vs 103 ± 4.4, P < 0.05), and average (199 ± 3.9 vs 119 ± 3.9, P < 0.05) numbers of IPCLs/field were also significantly greater in GERD patients. However, comparison among groups of the three subtypes showed no significant differences or any linear trend, except that microerosions were present in 60% of the RE patients, but in only 35% and 30% of the NERD and BE patients, respectively (P < 0.05).

CONCLUSION: Patients with GERD, irrespective of subtype, have similar micro changes in the distal esophagus. The three forms of the disease are probably independent of each other.

Histomorphological differentiation of non-erosive reflux disease and functional heartburn in patients with PPI-refractory heartburn

BACKGROUND

Proton pump inhibitor (PPI)-refractory heartburn may be due to persistent gastro-oesophageal reflux, oesophageal hypersensitivity or functional heartburn (FH). The differentiation between non-erosive reflux disease (NERD) and FH may be very difficult. However, this differentiation is important for appropriate therapeutic management. Dilated intercellular spaces (DIS), papillary elongation (PE) and basal cell hyperplasia (BCH) can be all assessed by light microscopy. Whether these mucosal abnormalities allow the differentiation of NERD from FH in PPI-refractory patients is uncertain.

AIM

To assess histopathological findings by light microscopy in patients with refractory heartburn to differentiate NERD from FH.

METHODS

Sixty-two patients with PPI-refractory symptoms underwent EGD and MII-pH after pausing PPI medication for 2 weeks before investigation. Twenty-five subjects without upper gastrointestinal symptoms were included as controls. Symptom assessment was based on the reflux disease questionnaire (RDQ). Biopsies were taken 3-5 cm above the gastro-oesophageal junction. DIS, PE, BCH and infiltration of immune cells were evaluated and a sum score was calculated.

RESULTS

Based on endoscopy and MII-pH, GERD was diagnosed in 43 patients (NERD: 20; ERD: 23) and FH in 19 patients. There was no difference in symptoms between the groups. Each individual histopathological item was different between the groups (P < 0.0001). Between NERD and FH, the most significant difference was found for DIS and the histopathological sum score (P < 0.001).

CONCLUSIONS

These findings suggest that oesophageal biopsies are useful to differentiate NERD from FH. Increased DIS and a histological sum score are the most significant histopathological abnormalities in NERD as compared with FH.

Current advances in the diagnosis and treatment of nonerosive reflux disease

Nonerosive reflux disease (NERD) is a distinct pattern of gastroesophageal reflux disease (GERD). It is defined as a subcategory of GERD characterized by troublesome reflux-related symptoms in the absence of esophageal mucosal erosions/breaks at conventional endoscopy. In clinical practice, patients with reflux symptoms and negative endoscopic findings are markedly heterogeneous. The potential explanations for the symptom generation in NERD include microscopic inflammation, visceral hypersensitivity (stress and sleep), and sustained esophageal contractions. The use of 24-hour esophageal impedance and pH monitoring gives further insight into reflux characteristics and symptom association relevant to NERD. The treatment choice of NERD still relies on acid-suppression therapy. Initially, patients can be treated by a proton pump inhibitor (PPI; standard dose, once daily) for 2–4 weeks. If initial treatment fails to elicit adequate symptom control, increasing the PPI dose (standard dose PPI twice daily) is recommended. In patients with poor response to appropriate PPI treatment, 24-hour esophageal impedance and pH monitoring is indicated to differentiate acid-reflux-related NERD, weakly acid-reflux-related NERD (hypersensitive esophagus), nonacid-reflux-related NERD, and functional heartburn. The response is less effective in NERD as compared with erosive esophagitis.

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.

Microscopic esophagitis distinguishes patients with non-erosive reflux disease from those with functional heartburn

BACKGROUND

Microscopic esophagitis (ME) is common in patients with non-erosive reflux disease (NERD), and dilation of intercellular spaces (DIS) has been regarded as the potential main mechanism of symptom generation. We aimed to compare these histological abnormalities in healthy volunteers (HVs) and patients with erosive esophagitis (EE), NERD, and functional heartburn (FH).

METHODS

Consecutive patients with heartburn prospectively underwent upper endoscopy and impedance-pH off-therapy. Twenty EE patients and fifty-seven endoscopy-negative patients (NERD), subclassified as 22 with pH-POS (positive for abnormal acid exposure), 20 with hypersensitive esophagus (HE; normal acid/symptom association probability [SAP]+ or symptom index [SI]+), and 15 with FH (normal acid/SAP-/SI-/ proton pump inhibitor [PPI] test-), were enrolled. Twenty HVs were also included. In each patient/control, multiple specimens (n = 5) were taken from the distal esophagus and histological alterations were evaluated. ME was diagnosed when the global histological score was >0.35.

RESULTS

The prevalence of ME was higher (p < 0.0001) in EE (95 %), pH-POS (77 %), and HE (65 %) NERD patients than in FH patients (13 %) and HVs (15 %). Also, basal cell hyperplasia (p < 0.0023), DIS (p < 0.0001), and papillae elongation (p < 0.0002) showed similar rates of prevalence in the above populations (p < 0.0001). ME, including each histological lesion, had similar low frequencies in FH and HVs (p = 0.9990). Considering the histological abnormalities together, they permitted us to clearly differentiate EE and NERD from FH and HVs (p < 0.0001 and p < 0.0001, respectively).

CONCLUSIONS

The lack of ME in the esophageal distal biopsies of FH patients indicates a limited role of these histological abnormalities in symptom generation in them. ME can be considered as an accurate and reliable diagnostic marker for distinguishing FH patients from GERD patients and has the potential to be used to guide the correct therapy.

Oesophageal mucosal intercellular space diameter and reflux pattern in childhood erosive and non-erosive reflux disease

BACKGROUND AND AIMS

We sought to compare intercellular space diameter in children with non-erosive and erosive reflux disease, and a control group. We also aimed to characterize the reflux pattern in erosive and non-erosive reflux disease patients, and to explore the relationship between intercellular space diameter values and reflux parameters.

METHODS

Twenty-four children with non-erosive reflux disease, 20 with erosive reflux disease, and 10 controls were prospectively studied. All patients and controls underwent upper endoscopy. Biopsies were taken at 2-3 cm above the Z-line, and intercellular space diameter was measured using transmission electron microscopy. Non-erosive and erosive reflux disease patients underwent impedance-pH monitoring.

RESULTS

Mean intercellular space diameter values were significantly higher in both non-erosive (0.9 ± 0.2 μm) and erosive reflux disease (1 ± 0.2 μm) compared to controls (0.5 ± 0.2 μm, p<0.01). No difference was found between the two patient groups. Acid exposure time, the number of acid, weakly acidic and weakly alkaline reflux events did not differ between the two patient groups. No difference was found in the mean intercellular space diameter between non-erosive reflux disease children with and without abnormal acid exposure time (1 ± 0.3 vs. 0.9 ± 0.2 μm). No correlation was found between any reflux parameter and intercellular space diameter values.

CONCLUSIONS

Dilated intercellular space diameter seems to be a useful and objective marker of oesophageal damage in paediatric gastro-oesophageal reflux disease, regardless of acid exposure. In childhood, different gastro-oesophageal reflux disease phenotypes cannot be discriminated on the basis of reflux pattern.

[The Mexican consensus on gastroesophageal reflux disease. Part I]

BACKGROUND

The changes, advances, and new discoveries regarding different aspects of gastroesophageal reflux disease (GERD) have made it necessary to update the Mexican Consensus published in 2002.

AIMS

To elaborate a new Mexican Consensus on GERD.

METHODS

The general project coordinators selected six GERD experts to carry out an extensive review of the literature for the purpose of elaborating statements on the principal aspects of GERD. These were then placed under the consideration of specialists in the study of this disease. Definitive approval by all participants was reached using the modified Delphi method with three rounds of anonymous and iterative voting. The following scale was employed: A- in complete agreement; B- in agreement, but with minor concerns; C- in agreement, but with major concerns; D- in disagreement, but with major concerns; E- in disagreement, but with minor concerns; or F- in complete disagreement. Consensus was declared when 67.00% or more of the participants concurred on a category of agreement (A, B, or C).

RESULTS

A consensus was reached on 160 of the statements upon completion of the voting rounds, with 90.00% concurrence for the majority of them.

CONCLUSIONS

The 2011 Mexican Consensus on Gastroesophageal Disease is a practical and up-to-date consultation tool, providing the opinion of Mexican experts on all the new information available about this disease. It allows there to be homogeneity in diagnostic and therapeutic criteria, all of which serves to benefit our patients.

Impedance baseline and reflux perception in responder and non-responder non-erosive reflux disease patients

BACKGROUND

It was recently shown that GERD patients have lower impedance baseline (IB) values than healthy controls and, that the esophageal acid exposure time (AET) correlates with IB levels.

GOALS

To explore the sensitivity of IB measurements in NERD patients, responders and non-responders to PPIs, when compared with pH-impedance (MII-pH) variables, and to evaluate whether this variable could represent a marker of GERD symptoms. Reproducibility and inter-observer agreement of IB measurement were also assessed. Study. MII-pH tracings from 44 NERD responders and 22 non-responders were analysed. Ten healthy volunteers underwent the same protocol. IB values were measured at the distal and proximal esophagus. IB was also analysed in a subgroup of patients and in controls with two methods and by two blinded operators.

RESULTS

Mean IB values at the distal esophagus were significantly lower in NERD patients than in controls. IB values did not differ between responders and non-responders. Of the 8 responders with negative AET and symptom association probability (SAP), 3 (37.5%) showed IB values lower than controls. IB values in responders with positive and negative SAP were similar (1832 (1596-2068) Ω vs 1667 (1361-1973) Ω, p: n.s.). No differences were found between the IB values measured with the two methods and the inter-observer agreement was good.

CONCLUSIONS

IB is a promising and easy to calculate MII-pH variable and appears to increase the sensitivity of MII-pH monitoring. IB values cannot predict PPI response and are not associated with reflux perception in NERD patients.

Use of direct, endoscopic-guided measurements of mucosal impedance in diagnosis of gastroesophageal reflux disease

BACKGROUND & AIMS

Diagnostic tests for gastroesophageal reflux disease (GERD) are constrained because measurements are made at a single time point, so the long-term effects on the mucosa cannot be determined. We developed a minimally invasive system to assess changes in esophageal mucosal impedance (MI), a marker of reflux. We measured the extent of changes in MI along the esophagus and show that the device to assess MI can be used to diagnose patients with GERD.

METHODS

A single-channel MI catheter composed of a unique sensor array was designed to easily traverse the working channel of an upper endoscope. We performed a prospective longitudinal study of patients with erosive esophagitis (n = 19), nonerosive but pH-positive GERD (n = 23), and those without GERD (n = 27). MI was measured at the site of esophagitis as well as 2, 5, and 10 cm above the squamocolumnar junction. The MI values were compared among groups, at different levels along the esophageal axis.

RESULTS

Median MI values were significantly lower at the site of erosive mucosa (811 Ω; range, 621-1272 Ω) than other nonerosive regions (3723 Ω; range, 2421-4671 Ω; P = .001), and were significantly lower at 2 cm above the squamocolumnar junction in patients with GERD (2096 Ω; range, 1415-2808 Ω), compared with those without GERD (3607 Ω; range, 1973-4238 Ω; P = .008). There was a significant and graded increase in MI along the axis of the distal to proximal esophagus in patients with GERD that was not observed in individuals without reflux (P = .004).

CONCLUSIONS

Measurements of MI along the esophagus can be used to identify patients with GERD. ClinicalTrials.gov, number NCT01194323.

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.

Microalterations of esophagus in patients with non-erosive reflux disease: in-vivo diagnosis by confocal laser endomicroscopy and its relationship with gastroesophageal reflux

OBJECTIVES

Objectively diagnosing non-erosive reflux disease (NERD) is still a challenge. We aimed to evaluate the use of in-vivo confocal laser endomicroscopy (CLE) to examine the microalterations of the esophagus in patients with NERD and its relationship with reflux episodes monitored by multiple intraluminal impedance-pH (MII-pH).

METHODS

Patients with gastroesophageal reflux symptoms completed reflux disease questionnaires. NERD was determined by negative gastroscopy. Patients without reflux symptoms were recruited as controls. Pilot clinical study was followed by prospective controlled blinded study. All subjects were examined by white-light mode of the endoscopy followed by the standard CLE mode and then MII-pH monitoring. The microalterations seen on CLE images and the correlation between CLE features and reflux episodes were evaluated, the correlation between CLE and transmission electron microscope (TEM) data was also analyzed.

RESULTS

On CLE images, NERD patients had more intrapapillary capillary loops (IPCLs) per image than did controls (8.29 ± 3.52 vs. 5.69 ± 2.31, P=0.010), as well as the diameter of IPCLs (19.48 ± 3.13 vs. 15.87 ± 2.21 μm, P=0.041) and intercellular spaces of squamous cells (3.40 ± 0.82 vs. 1.90 ± 0.53 μm, P=0.042). The receiver operating characteristic analysis indicated that IPCLs number (optimal cutoff >6 per image, area under the curve (AUC) 0.722, 95% confidence interval (CI) 0.592-0.853, sensitivity 67.7%, specificity 71.6%), IPCLs diameter (optimal cutoff >17.2 μm, AUC 0.847, 95% CI 0.747-0.947, sensitivity 81%, specificity 76%), and the intercellular spaces of squamous cells (optimal cutoff >2.40 μm, AUC 0.935, 95% CI 0.875-0.995, sensitivity 85.7%, specificity 90.5%) diagnosed NERD with reasonable accuracy. Combined features of dilatation of intercellular space plus increased IPCLs provided 100% specificity in the diagnosis of NERD patients. The intercellular spaces of squamous cells observed on CLE were highly related to that on TEM findings (r=0.75, P<0.001). Multivariate progressive regression analysis showed that acidic reflux, especially in the supine position, was related to the increased number and dilation of IPCLs in the squamous epithelium (β=0.063, t=2.895, P=0.038 and β=0.156, t=1.023, P=0.04).

CONCLUSIONS

CLE represents a useful and potentially significant improvement over standard endoscopy to examine the microalterations of the esophagus in vivo. Acidic reflux is responsible for the microalterations in the esophagus of patients with NERD.

Gastro-oesophageal reflux disease is associated with up-regulation of desmosomal components in oesophageal mucosa

AIMS

Gastro-oesophageal reflux disease (GERD) is associated with impaired epithelial barrier function. This study was aimed at investigating the role of desmosomal proteins in relation to GERD.

METHODS AND RESULTS

Ninety-five patients with GERD-related symptoms (erosive, n = 51; non-erosive, n = 44) and 27 patients lacking those symptoms were included. Endoscopic and histological characterization of oesophagitis was performed according to the Los Angeles and Ismeil-Beigi criteria, respectively. Multiple biopsies were taken from the oesophageal mucosa of each patient. Gene expression analysis of plakoglobin, desmoglein-1, desmoglein-2 and desmoglein-3 was performed by quantitative real time (RT)-polymerase chain reaction and immunohistochemistry in the oesophageal mucosa. Routine histology revealed specific GERD-related alterations, such as dilatation of intercellular spaces (DIS), basal cell hyperplasia (BCH), and elongation of the papillae, in the oesophageal mucosa of patients with GERD, as compared with controls (all parameters: P < 0.05). All four genes and corresponding proteins were found to be up-regulated by between 1.7 and 8.1-fold (transcript level, P < 0.05; protein level, P < 0.05). Induced gene expression levels of plakoglobin, desmoglein-1 and desmoglein-2 correlated significantly with DIS and BCH.

CONCLUSIONS

Taken together, the uniform up-regulation of desmosomal genes/proteins in the oesophageal mucosa of patients with GERD supports the concept of architectural and molecular changes in the desmosomal compartment in the pathogenesis of GERD.

Evaluation of dilation of intercellular spaces of squamous epithelium in the lower esophagus in the diagnosis of non-erosive reflux disease

AIM: To evaluate the diagnostic value of dilation of intercellular spaces (DIS) of squamous epithelium in the lower esophagus for non-erosive reflux disease (NERD).

METHODS: Sixty-six NERD patients and thirty-eight healthy volunteers were enrolled. All participants underwent evaluation using the gastroesophageal reflux disease questionnaire (GerdQ), 24 h esophageal pH monitoring, gastroscopy, and biopsy of mucosa in the lower esophagus at the Z-line and 2 cm above the Z-line for measurement of diameter of intercellular spaces by transmission electron microscopy (TEM). NERD patients with negative pH monitoring results underwent proton pump inhibitor test to confirm the diagnosis.

RESULTS: The mean diameter of intercellular spaces of squamous epithelium at the Z-line and 2 cm above the Z-line were (0.90 ± 0.11) μm and (0.92 ± 0.16) μm in the NERD group, and were (0.65 ± 0.08) μm and (0.67 ± 0.08) μm in the control group, without significant differences within the groups (both P > 0.05), but with significant differences between the two groups (both P < 0.05). No significant differences in the mean diameter of intercellular spaces of squamous epithelium at the Z-line and 2 cm above the Z-line in NERD patients were observed between pH(+) and pH(-) groups and between GerdQ(+) and GerdQ(-) groups. Positive correlations were found between the DeMeester scores and mean intercellular space diameters either at the Z-line (r = 0.33, P = 0.001) or 2 cm above the Z-line (r = 0.35, P = 0.001), and between the GerdQ scores and mean intercellular space diameters either at the Z-line (r = 0.32, P = 0.006) or 2 cm above the Z-line (r = 0.45, P < 0.001). The best cut-off values for mean intercellular space diameter were both 0.81 μm at the Z-line and 2 cm above the Z-line, with a highest Youden index of 0.808 at the Z-line (sensitivity 80.8%, specificity 100%) and 0.731 2 cm above the Z-line (sensitivity 78.8%, specificity 97.4%).

CONCLUSION: The diameter of intercellular spaces of squamous epithelium in the lower esophagus of patients with NERD is significantly increased and correlates with acid reflux and reflux symptoms. Dilated intercellular space can serve as a sensitive and objective histopathological indicator for the diagnosis of NERD.

Eosinophils in the oesophageal mucosa: clinical, pathological and epidemiological relevance in children: a cohort study

Objectives Eosinophilic oesophagitis (EO) shows eosinophilic infiltration of the mucosa and can present with symptoms indistinguishable from gastrooesophageal reflux disease (GORD). The authors describe the clinical, endoscopic and histopathological features of all cases of histological EO presenting during 2007-2008 with a 2-year follow-up. The incidence of paediatric EO and the features of a subgroup with features of both GORD and EO ('overlap' syndrome (OS)) are described. Design Biopsies with an average of 15 eosinophils/high-power field (HPF) were reviewed in the cohort. OS was suggested when there was coexistence of clinical and histological features of EO and GORD (abnormal pH study), which improved with proton pump inhibitors. Setting Tertiary care. Participants All cases with ≥15 eosinophils/HPF entered the study. Primary outcome measures Patients with EO had an average of 15 eosinophils/HPF. Secondary outcome measures Other histological features of EO included microabscesses, dilated intercellular spaces, basal cell hyperplasia, papillary elongation, etc. Results 24 cases of EO were identified, 13 men and 11 women. The incidence of paediatric oesophageal eosinophilia in the region was 9/100 000 children. 11 of the 24 patients (46%) presented with some form of allergy, six with poor feeding/food aversion, five with dysphagia and four with vomiting. After follow-up, 56.5% were confirmed to have EO, 30.5% responded to treatment for GORD and were categorised as OS, 9% developed eosinophilic gastroenteritis and 4% did not have further upper gastrointestinal symptoms. Conclusions Accurate diagnosis of EO, especially the differentiation from GORD, requires appropriate clinicopathological correlation. A significant proportion of patients with eosinophilia in the mucosa also have GORD (OS). These patients improve after treating the underlying GORD. The study was registered as a Service Evaluation with the Trust (number SE74).

Is intercellular space different among layers in normal esophageal mucosa? An electron microscopic study

BACKGROUND/INTRODUCTION

Dilatation of intercellular space (IS) of esophageal epithelial cells is described as a sensitive early marker for epithelial damage by refluxate. Esophageal epithelia are morphologically subdivided into three layers according to the shape of the cells and nuclei. Meanwhile, ten transmission electron microscopy (TEM) photographs and ten randomly selected measurements per photo from gastroesophageal reflux disease (GERD) patients have been widely accepted without any theoretical criticism. We assumed that the IS differs among each layer and thus studied IS according to subdivided layers of normal esophageal epithelium. We also evaluated an optimal number of IS measurements per photograph.

MATERIALS AND METHODS

Esophagogastroduodenoscopy was performed in 15 healthy adults without any symptom of GERD, taking biopsies from mucosa above 5 cm from the squamo-columnar junction. Tissues were handled and prepared for TEM, verifying three layers of esophageal mucosa, i.e., squamous cell layer, prickle cell layer, and basal layer. Ten digital photomicrographs were taken from each three layers by TEM, and ISs were measured with a computerized image analysis program. For the method of measuring IS, 5, 10, 20, 30, and 40 measurements per photomicrograph were respectively performed by four different examiners. Mean value and intraclass correlation coefficient (ICC) was also yielded.

RESULTS

Mean IS of lower esophagus irrelevant to three epithelial layers were 0.39 ± 0.30 μm. When subdivided into three layers, however, mean IS of squamous cell layer was 0.62 ± 0.23 μm, prickle cell layer 0.23 ± 0.19 μm, and basal layer 0.55 ± 0.36 μm, with their difference statistically significant (p < 0.05). On the other hand, ICC of 5, 10, 20, 30, and 40 measurements were 0.688, 0.917, 0.837, 0.790, and 0.765, respectively.

CONCLUSIONS

Mean IS values of each three layers of esophageal epithelium in normal subjects were significantly different, and reconsideration of the standard measurement method is needed. Ten measurements per photo had an adequate inter-observer agreement.

Barrett's esophagus: progression to adenocarcinoma and markers

The following on progression to adenocarcinoma and markers of Barrett's esophagus includes commentariess on the expression of claudin 4 in Barrett's adenocarcinoma; the role of acid and bile salts; the role of insulin-like growth factor; the value of reactive oxygen species; the importance of abnormal methylation; genetic alterations in stromal cells and genomic changes in the epithelial cells; the value of confocal laser endomicroscopy for the subsurface analysis of the mucosa; indications for statins as adjuvant chemotherapeutic agent; the sequence of molecular events in malignant progression in Barrett's mucosa; and the value of the macroscopic markers and of p53 mutations.

Mechanisms underlying visceral hypersensitivity in irritable bowel syndrome

Visceral hypersensitivity is currently considered a key pathophysiological mechanism involved in pain perception in large subgroups of patients with functional gastrointestinal disorders, including irritable bowel syndrome (IBS). In IBS, visceral hypersensitivity has been described in 20%-90% of patients. The contribution of the central nervous system and psychological factors to visceral hypersensitivity in patients with IBS may be significant, although still debated. Peripheral factors have gained increasing attention following the recognition that infectious enteritis may trigger the development of persistent IBS symptoms, and the identification of mucosal immune, neural, endocrine, microbiological, and intestinal permeability abnormalities. Growing evidence suggests that these factors play an important role in pain transmission from the periphery to the brain via sensory nerve pathways in large subsets of patients with IBS. In this review, we will report on recent data on mechanisms involved in visceral hypersensitivity in IBS, with particular attention paid to peripheral mechanisms.

Lansoprazole-induced improvement of esophageal submucosal injury

The proton pumpvinhibitor, lansoprazole, is reported to have acid secretion inhibiting effect as well as anti-inflammatory effects such as inhibition of cytokine secretion from inflammatory cells. Clinically, excellent efficacy of lansoprazole is reported for not only gastric ulcer but also gastroesophageal reflux disease (GERD). Since GERD is categorized endoscopically into erosive esophagitis and non-erosive reflux disease, it is important to make accurate assessment of any improvement in the inflammatory process when using endoscopic ultrasonography (EUS) capable of visualizing the submucosal structure. We report here our experience in assessing the effect of treatment with lansoprazole on esophageal wall structure using EUS in patients with GERD. At baseline (before treatment), EUS showed abnormalities in the mucosa, submucosa and muscularis propria caused by inflammation, thickening of the entire esophageal wall and changes in the contractile properties of esophageal smooth muscles reflecting the effects of inflammation on the entire wall of the lower esophagus in reflux esophagitis regardless of whether it is erosive or endoscopically-negative. Treatment with lansoprazole resulted in normalization of esophageal wall structure and improvement of motility, suggesting that lansoprazole improves not only mucosal inflammation but also submucosal inflammation in GERD.

Role of E-cadherin in the pathogenesis of gastroesophageal reflux disease

OBJECTIVES

An early event in the pathogenesis of gastroesophageal reflux disease (GERD) is an acid-induced increase in junctional (paracellular) permeability in esophageal epithelium (EE). The molecular events that account for this change are unknown. E-cadherin is a junctional protein important in barrier function in EE. Therefore, defects in barrier function in EE were sought in GERD as well as whether their presence correlated with abnormalities in e-cadherin.

METHODS

Endoscopic biopsies of EE from GERD (n=20; male 10; female 10; mean age 50 ± 10 years) and subjects with a healthy esophagus (controls; n=23; male 11; female 12; mean age 51 ± 11 years) were evaluated in mini-Ussing chambers and by western blot and immunochemistry; and serum analyzed by enzyme-linked immunosorbent assay (ELISA). A role for e-cadherin was also assessed using a unique conditional knockout of e-cadherin in adult mouse esophagus.

RESULTS

EE from GERD patients had lower electrical resistance and higher fluorescein flux than EE from controls; and the findings in GERD associated with cleavage of e-cadherin. Cleavage of e-cadherin in GERD was documented in EE by the presence of a 35-kDa, C-terminal fragment of the molecule on western blot and by an increase in soluble N-terminal fragments of the molecule in serum. Activation of the membrane metalloproteinase, A Disintegrin And Metalloproteinase (ADAM-10), was identified as a likely cause for cleavage of e-cadherin by western blot and immunostaining and a role for e-cadherin in the increased junctional permeability in EE from GERD supported by showing increased permeability after deletion of e-cadherin in mouse EE.

CONCLUSIONS

The EE in GERD has increased junctional permeability and this is in association with proteolytic cleavage of e-cadherin. As loss of e-cadherin can, alone, account for the increase in junctional permeability, cleavage of e-cadherin likely represents a critical molecular event in the pathogenesis of GERD, and identification of cleaved fragments may, if confirmed in larger studies, be valuable as a biomarker of GERD.