Lowered oesophageal sensory thresholds in patients with symptomatic but not excess gastro-oesophageal reflux: evidence for a spectrum of visceral sensitivity in GORD

Physiological Archetypes of de novo Gastroesophageal Reflux Disease After Laparoscopic Sleeve Gastrectomy

Laparoscopic Sleeve Gastrectomy (LSG) is the most common bariatric surgery in the world. While clinically effective, recent studies have shown increasingly higher rates of gastroesophageal reflux disease (GERD) and esophageal motility disorders. We reviewed all the literature and unraveled the underlying mechanism of post-LSG GERD. Finally, we propose a new classification to help us understand the disease and guide work-up, treatment, and future refinements in the surgical technique.

Esophageal Reflux Hypersensitivity: A Comprehensive Review

Reflux hypersensitivity (RH) is one of the phenotypes of gastroesophageal reflux disease. The latest Rome IV defines RH as a condition with typical reflux symptoms and positive reflux-symptom association despite normal acid exposure. Subsequently, the Lyon consensus proposed detailed cutoff values for the criteria on the basis of experts' consensus. Rome IV brought a clear-cut perspective into the pathophysiology of gastroesophageal reflux disease and the importance of esophageal hypersensitivity. This perspective can be supported by the fact that other functional gastrointestinal disorders such as irritable bowel syndrome and functional dyspepsia often overlap with RH. Although several possible pathophysiological mechanisms of esophageal hypersensitivity have been identified, there is still unmet medical needs in terms of treatment for this condition. This review summarizes the current knowledge regarding RH.

The Real Relevance of Nonacid Reflux in Pediatric Patients

Gastroesophageal reflux (GER) is one of the most common presenting complaints to pediatric gastroenterologists, and a wide variety of symptoms in children are potentially attributable to typical or atypical GER. While reflux diagnosis and treatment paradigms classically have focused on targeting acid, there is a growing recognition of the prevalence and significance of nonacid GER in both children and adults. This review explores the role of nonacid reflux in pediatric patients, including definitions, associations with symptoms, pathophysiologic mechanisms, and treatment implications.

Features of the Parameters of 24-Hours pH-Impedance and High-Resolution Esophageal Manometry in Patients with Barrett's Esophagus on Proton Pump Inhibitors

Аim: to identify predictors of insufficient effectiveness of proton pump inhibitors based on the evaluation of the results of 24-hour pH-impedance and high-resolution esophageal manometry in patients with Barrett's esophagus.

Materials and methods. 52 patients with histologically confirmed Barrett's esophagus who are on therapy with proton pump inhibitors were examined. All patients underwent daily pH-impedance and high-resolution esophageal manometry.

Results. According to daily pH-impedance, group 1 consisted of 37 patients who responded satisfactorily to antisecretory therapy, group 2 of 15 patients who demonstrated insufficient response to acid-suppressive therapy, 11 of whom had no clinical manifestations. The total number of reflux averaged 55 in group 1 and 106 in group 2. The average number of acid reflux in group 1 was 5.68, in group 2 — 48.5. The average number of non-acid reflux prevailed in patients of group 2 and averaged 58, in group 1 the indicator averaged 47. Evaluation of the results of high-resolution esophageal manometry showed that violations of the structure and function of the esophago-gastric junction were detected in 21 patients out of 52. Disorders of the motility of the thoracic esophagus were detected in 31 patients out of 52. When comparing the frequency of motor disorders from the thoracic esophagus in groups 1 and 2, no significant differences were obtained. However, significantly more frequent registration of violations of the structure and/or function of the esophago-gastric junction was found in the group with unsatisfactory effectiveness of proton pump inhibitors.

Conclusion. In a number of patients with Barrett's esophagus, there is an insufficient effect of acid-suppressive therapy and at the same time an asymptomatic course of the disease, which may increase the risk of its progression. Predictors of insufficiently successful treatment of patients with Barrett's esophagus may be both insufficient pharmacological effect of proton pump inhibitors themselves, and motility disorders that cause the presence of non-acid reflux, decreased esophageal clearance, which in turn may cause the patient's symptoms to persist and adversely affect the condition of the esophageal mucosa.

Features of the Parameters of 24-Hours pH-Impedance and High-Resolution Esophageal Manometry in Patients with Barrett's Esophagus on Proton Pump Inhibitors

Аim: to identify predictors of insufficient effectiveness of proton pump inhibitors based on the evaluation of the results of 24-hour pH-impedance and high-resolution esophageal manometry in patients with Barrett's esophagus.

Materials and methods. 52 patients with histologically confirmed Barrett's esophagus who are on therapy with proton pump inhibitors were examined. All patients underwent daily pH-impedance and high-resolution esophageal manometry.

Results. According to daily pH-impedance, group 1 consisted of 37 patients who responded satisfactorily to antisecretory therapy, group 2 of 15 patients who demonstrated insufficient response to acid-suppressive therapy, 11 of whom had no clinical manifestations. The total number of reflux averaged 55 in group 1 and 106 in group 2. The average number of acid reflux in group 1 was 5.68, in group 2 — 48.5. The average number of non-acid reflux prevailed in patients of group 2 and averaged 58, in group 1 the indicator averaged 47. Evaluation of the results of high-resolution esophageal manometry showed that violations of the structure and function of the esophago-gastric junction were detected in 21 patients out of 52. Disorders of the motility of the thoracic esophagus were detected in 31 patients out of 52. When comparing the frequency of motor disorders from the thoracic esophagus in groups 1 and 2, no significant differences were obtained. However, significantly more frequent registration of violations of the structure and/or function of the esophago-gastric junction was found in the group with unsatisfactory effectiveness of proton pump inhibitors.

Conclusion. In a number of patients with Barrett's esophagus, there is an insufficient effect of acid-suppressive therapy and at the same time an asymptomatic course of the disease, which may increase the risk of its progression. Predictors of insufficiently successful treatment of patients with Barrett's esophagus may be both insufficient pharmacological effect of proton pump inhibitors themselves, and motility disorders that cause the presence of non-acid reflux, decreased esophageal clearance, which in turn may cause the patient's symptoms to persist and adversely affect the condition of the esophageal mucosa.

The relationship between esophageal acidity and symptom frequency in symptomatic nonerosive gastroesophageal reflux disease

The present paper examines the extent to which novel measures of esophageal acid exposure can elucidate possible relationships between symptom perception and esophageal acidity in subjects with nonerosive gastroesophageal reflux disease. Recordings of esophageal pH and symptom occurrence from 20 subjects with nonerosive gastroesophageal reflux disease were analyzed. Interval esophageal acid exposure was calculated in two different ways for the interval that preceded each symptom in each subject. Interval esophageal acidity was calculated as the time-weighted acid concentration for the interval. Interval esophageal acid exposure time was calculated as the percentage of the total recording time that esophageal pH was less than pH 4 for the interval. There was a negative relationship between the probability of a symptom and interval esophageal acid exposure indicating the paradoxical finding that the lower the value of esophageal acid exposure, the higher the probability of a symptom. The time courses of symptoms and cumulative esophageal acidity resolved this paradox by indicating that esophageal acid exposure oscillates between longer periods of low esophageal acid exposure with a high number of symptoms reflecting high esophageal acid sensitivity, and shorter periods of high esophageal acid exposure with fewer symptoms reflecting low esophageal acid sensitivity. Thus, the present analyses show how novel measures of acidity can identify and also resolve a previously unrecognized paradoxical relationship between esophageal acid exposure and symptom frequency in subjects with nonerosive gastroesophageal reflux disease.

Association Between Psychosocial Disorders and Gastroesophageal Reflux Disease: A Systematic Review and Meta-analysis

Background/Aims

The incidence of gastroesophageal reflux disease (GERD) is increasing annually. Studies have suggested that psychosocial disorders may be linked to the development of GERD. However, studies evaluating the association between psychosocial disorders and GERD have been inconsistent. Thus, we conducted a systematic review and meta-analysis of observational studies that evaluated the association between psychosocial disorders and GERD.

Methods

We systematically searched the PubMed, Embase, Cochrane, and Web of Science databases until October 17, 2020. Pooled OR with 95% CI and subgroup analyses were calculated using a random-effects model. Subgroup analyses were performed to identify the sources of heterogeneity. Sensitivity analysis by one-study removal was used to test the robustness of our results.

Results

This meta-analysis included 1 485 268 participants from 9 studies. Studies using psychosocial disorders as the outcome showed that patients with GERD had a higher incidence of psychosocial disorders compared to that in patients without GERD (OR, 2.57; 95% CI, 1.87-3.54; I2 = 93.8%; P < 0.001). Studies using GERD as an outcome showed an association between psychosocial disorders and an increased risk of GERD (OR, 2.23; 95% CI, 1.42-3.51; I2 = 97.1%; P < 0.001). The results of the subgroup analysis showed that the non-erosive reflux disease group had a higher increased risk of anxiety than erosive reflux disease group (OR, 9.45; 95% CI, 5.54- 16.13; I2 = 12.6%; P = 0.285).

Conclusion

Results of our meta-analysis showed that psychosocial disorders are associated with GERD; there is an interaction between the two.

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

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

[Complex assessment of esophageal acidification and motor function in patients with Barrett's esophagus on antisecretory therapy]

AIM

To determine predictors of insufficient effectiveness of proton pump inhibitors based on the parameters of 24-hours pH-impedance and features of motor function of the esophagus in patients with Barrett's esophagus.

MATERIALS AND METHODS

17 patients with histologically verified Barrett's esophagus undergoing acid-suppressive therapy were examined. All patients underwent 24-hours pH-impedance and high-resolution esophageal manometry.

RESULTS

According to daily pH-impedance, group 1 consisted of 11 patients with an adequate response to antisecretory therapy, group 2 6 patients with insufficient effectiveness of antisecretory therapy, 5 of whom had no clinical manifestations. The total number of reflux averaged 52 and 91, respectively, in groups 1 and 2. The average number of acid reflux in group 1 was 4.36, in group 2 40.5. The average number of non-acid reflux prevailed in patients of group 2, averaging 58, compared with group 1, where the average was 47. According to the results of high-resolution esophageal manometry, when assessing the structure and function of the esophageal-gastric junction, violations were detected in 6 out of 17 patients. Disorders of the motor function of the thoracic esophagus were detected in 10 out of 17 patients. The tone of the lower esophageal sphincter in group 1 patients was significantly higher in comparison with patients in group 2.

CONCLUSION

A number of patients with Barrett's esophagus have insufficient effectiveness of antisecretory therapy, which may not manifest itself clinically and thereby increase the risk of progression. There was a tendency to more frequent motor disorders in the group with insufficient effectiveness of antisecretory therapy, as well as significantly lower tone of the lower esophageal sphincter, which may be a potential predictor of suboptimal effectiveness of antisecretory therapy.

Asymptomatic Barrett’s Oesophagus-Complicated Gastroesophageal Reflux Disease at Ineffective Antisecretory Therapy

Aim. A clinical description of gastroesophageal reflux disease (GERD) complicated by Barrett’s oesophagus (BO) at inadequate antisecretory therapy and the assessment of functional tests in control of conservative treatment.

Key points. A 63-yo patient with no complaints in a proton pump inhibitor (PPI) therapy was admitted for a follow-up examination for BO-complicated GERD using oesophagogastroduodenoscopy (OGDS) with biopsy, high-resolution oesophageal manometry and 24-h pH-impedance. Endoscopy revealed signs of BO (long segment C1M3), erosive reflux oesophagitis (grade B in Los Angeles classification). Non-contractile oesophagus in manometry. Antisecretory therapy was stated ineffective and subject to correction in 24-h pH-impedance.

Conclusion. Asymptomatic BO-complicated GERD patients comprise a special cohort. The main challenge to prevent progression into oesophageal adenocarcinoma is an adequate personalised patient management leveraging the modern diagnostic techniques, control of antisecretory treatment and its correction a situ.

ESNM/ANMS consensus paper: Diagnosis and management of refractory gastro-esophageal reflux disease

Up to 40% of patients with symptoms suspicious of gastroesophageal reflux disease (GERD) do not respond completely to proton pump inhibitor (PPI) therapy. The term "refractory GERD" has been used loosely in the literature. A distinction should be made between refractory symptoms (ie, symptoms may or may not be GERD-related), refractory GERD symptoms (ie, persisting symptoms in patients with proven GERD, regardless of relationship to ongoing reflux), and refractory GERD (ie, objective evidence of GERD despite adequate medical management). The present ESNM/ANMS consensus paper proposes use the term "refractory GERD symptoms" only in patients with persisting symptoms and previously proven GERD by either endoscopy or esophageal pH monitoring. Even in this context, symptoms may or may not be reflux related. Objective evaluation, including endoscopy and esophageal physiologic testing, is requisite to provide insights into mechanisms of symptom generation and evidence of true refractory GERD. Some patients may have true ongoing refractory acid or weakly acidic reflux despite PPIs, while others have no evidence of ongoing reflux, and yet others have functional esophageal disorders (overlapping with proven GERD confirmed off therapy). In this context, attention should also be paid to supragastric belching and rumination syndrome, which may be important contributors to refractory symptoms.

Modified Reflux Scintigraphy Detects Pulmonary Microaspiration in Severe Gastro-Esophageal and Laryngopharyngeal Reflux Disease

INTRODUCTION

Previously described methodologies for detecting laryngopharyngeal reflux (LPR) have limitations. Symptoms alone are non-diagnostic, and pH-impedance studies have poor sensitivity. Pulmonary micro-aspiration is under-recognised in LPR and gastro-esophageal reflux disease (GERD). The present study aimed to describe the results of a modified technique for scintigraphic reflux studies in two groups with severe reflux: those with typical reflux symptoms and those with laryngopharyngeal manifestations of reflux.

METHODS

A prospective database of severely symptomatic, treatment-resistant reflux patients was grouped based upon predominant symptom profile of typical GERD or LPR. All patients underwent reflux scintigraphy. Results were obtained for early scintigraphic reflux contamination of the pharynx and proximal esophagus, and delayed contamination of the pharynx and lungs after 2 h.

RESULTS

187 patients were studied (82 GERD, 105 LPR). The LPR patients were predominantly female (70.5% vs. 56.1%; p = 0.042) and older than the GERD group (median age 60 years vs. 55.5 years; p = 0.002). Early scintigraphic reflux was seen at the pharynx in 89.2% (GERD 87.7%, LPR 90.4%; p = 0.133), and at the proximal esophagus in 89.7% (GERD 88.9%, LPR 90.4%; p = 0.147). Delayed contamination of the pharynx was seen in 95.2% (GERD 93.9%, LPR 96.2%; p = 0.468). Delayed pulmonary aspiration was seen in 46% (GERD 36.6%, LPR 53.3%; p = 0.023).

CONCLUSION

Reflux scintigraphy demonstrated a high rate of reflux-related pulmonary aspiration. Contamination of the proximal esophagus and pharynx was observed frequently in both groups of severe disease. The likelihood of pulmonary aspiration and potential pulmonary disease needs to be entertained in severe GERD and LPR.

Reflux Hypersensitivity: How to Approach Diagnosis and Management

PURPOSE OF REVIEW

This paper aims to review the definition and diagnostic criteria for reflux hypersensitivity and comment on the present and future management of this condition.

RECENT FINDINGS

In 2016, the Rome IV criteria redefined reflux hypersensitivity as characterized by typical reflux symptoms, absence of endoscopic mucosal disease, absence of pathologic gastroesophageal reflux, and positive symptom correlation between reflux and heartburn episodes. Though uncertain, TPRV1 receptors have been implicated in the pathophysiology of reflux hypersensitivity. Recent studies have shown neuromodulators like SSRIs, SNRIs, and TCAs may be the future of managing this condition. With the release of the Rome IV criteria and availability of continuous pH monitoring, the diagnosis of reflux hypersensitivity has become more streamlined. Though there is no definitive therapy for reflux hypersensitivity, several anti-secretory agents and neuromodulators have shown some efficacy in therapeutic trials. The lack of large-scale, randomized controlled trials, however, reinforces the need for further research into the pharmacotherapy of reflux hypersensitivity.

Esophageal Function Abnormalities in Patients With Barrett's Esophagus

Various esophageal functional abnormalities have been described in patients with Barrett's esophagus (BE). A significantly higher esophageal acid exposure especially in the supine position has been documented in BE, as compared with the other gastroesophageal reflux disease phenotypes. In addition, weakly acidic reflux and duodenogastroesophageal reflux are more common in BE patients. The presence of Barrett's mucosa reduces esophageal mucosal impedance, occasionally to a level that prevents detection of reflux episodes. Reduced amplitude contractions and lower esophageal sphincter basal pressure are more common in BE patients as compared with the other gastroesophageal reflux disease groups. Ineffective esophageal motility is the most commonly defined motor disorder in BE. Reduced chemoreceptor and mechanoreceptor sensitivity to acid and balloon distention, respectively, have been suggested to explain lack or significantly less reports of reflux-related symptoms by BE patients.

Revisiting Montreal: New Insights into Symptoms and Their Causes, and Implications for the Future of GERD

The Montreal definition of gastroesophageal reflux disease (GERD) provided a rationale for acid suppression medication without investigation, thus enhancing the management of the substantial symptom burden in these patients. Increased proton-pump inhibitor use has also highlighted their limitations, with one third of "typical" symptoms known to be refractory. Most refractory symptoms are ascribed to reflux hypersensitivity (RH) and functional heartburn (FH). RH may be caused by impaired esophageal mucosal barrier function and sensitization of peripheral esophageal receptors. Central sensitization may also contribute to the perception of non-pathologic reflux in RH, and the perception of physiological stimuli in FH. Importantly, mechanisms underlying GERD, RH, and FH are (in theory) not mutually exclusive, further complicating patient management. Methods used to distinguish GERD from RH and FH are impractical for use in epidemiological studies and pragmatic care and may have limited diagnostic accuracy. This is impeding accurate prevalence estimates and risk factor determination and the identification of new therapies. Direct assessment of mucosal barrier function by measuring impedance is a promising candidate for improved diagnosis. Ultimately though the concept of GERD as a composite, symptom-based entity needs re-evaluation, so that new understandings of upper GI symptoms can direct more precise management.

Role of Esophageal Motility, Acid Reflux, and of Acid Suppression in Nonobstructive Dysphagia

GOALS

The present study was aimed at evaluating, in dysphagic patients, the role of high-resolution manometry (HRM) findings, presence of gastroesophageal reflux disease (GERD), and proton-pump inhibitor (PPI) therapy on dysphagia perception.

BACKGROUND

A relevant proportion of patients with nonobstructive dysphagia present normal esophageal HRM findings. Patients with GERD often complain of dysphagia and factors, such as hypersensitivity, might be involved in its occurrence.

STUDY

In total, 37 nonerosive reflux disease (NERD) patients with only dysphagia (group 1) and 52 patients with both dysphagia and typical GERD symptoms (group 2) were evaluated with symptom scores, HRM combined with impedance and 24 hours impedance-pH monitoring. In total, 44 NERD patients, not presenting dysphagia, underwent the same protocol. A total of 22/37 group 1 patients [11 with pathologic acid exposure time (AET)] were treated with esomeprazole 40 mg oid for 4 weeks and were reassessed during the last week of therapy.

RESULTS

A total of 15/37 group 1 patients (40%), 27/52 group 2 patients (52%), and 19/44 (43%) NERD patients presented pathologic AET [P=not significant (NS)]. Group 1 patients with a pathologic AET showed a significantly lower mean distal contractile integral (DCI) and a significant correlation (ρ=-0.71) between individual DCI and total bolus transit time values. During PPI therapy, in group 1 patients with pathologic AET, the mean dysphagia score value decreased significantly [7.5 (range, 3 to 9) before, 4 (range, 2 to 6) during PPI; P<0.01)] and mean DCI value increased significantly.

CONCLUSIONS

In total, 40% of dysphagic patients show a pathologic AET and reduced peristaltic vigor. In these patients, an adequate PPI therapy significantly decreases dysphagia frequency and severity and improves the esophageal peristaltic force.

Genetic risk factors for perception of symptoms in GERD: an observational cohort study

BACKGROUND

Genetic polymorphisms in G-protein beta-3 subunit (GNβ3) and beta-2 adrenergic receptor (ADRB2) are associated with pain and gut hypersensitivity, which can overlap with gastroesophageal reflux disease (GERD).

AIM

To evaluate relationships between single nucleotide polymorphisms (SNPs) within GNβ3 and ADRB2 systems, and reflux symptom burden, GERD phenotypes from ambulatory reflux monitoring, and quality of life.

METHODS

Symptomatic adults undergoing ambulatory reflux testing were recruited and phenotyped based on acid burden and symptom reflux association; major oesophageal motor disorders and prior foregut surgery were exclusions. A comparison asymptomatic control cohort was also identified. Subjects and controls completed questionnaires assessing symptom burden on visual analog scales, short-form health survey-36 (SF-36), and Beck Anxiety and Depression Inventories (BAI and BDI). Genotyping was performed from saliva samples; 6 SNPs selected from each of the two genes of interest were compared.

RESULTS

Saliva from 151 study subjects (55.3 ± 1.2 years, 63.6% F) and 60 control subjects (50.9 ± 2.2 years, 66.7%) had sufficient genetic material for genotyping. Study subjects had higher symptom burden, worse total and physical health, and higher anxiety scores compared to controls (P ≤ .002). Tested SNPs within ADRB2 were similar between study subjects and controls (P > .09). Study subjects with recessive alleles in 3 GNβ3 SNPs (Rs2301339, Rs5443, and Rs5446) had worse symptom severity (P = .011), worse mental health (P = .03), and higher depression scores (P = .005) despite no associations with GERD phenotypes or reflux metrics.

CONCLUSIONS

Genetic variation within GNβ3 predicts oesophageal symptom burden and affect, but not oesophageal acid burden or symptom association with reflux episodes.

Pathophysiology of Gastroesophageal Reflux Disease

The pathogenesis of gastroesophageal reflux disease (GERD) is complex and involves changes in reflux exposure, epithelial resistance, and visceral sensitivity. The gastric refluxate is a noxious material that injures the esophagus and elicits symptoms. Esophageal exposure to gastric refluxate is the primary determinant of disease severity. This exposure arises via compromise of the anti-reflux barrier and reduced ability of the esophagus to clear and buffer the refluxate, leading to reflux disease. However, complications and symptoms also occur in the context of normal reflux burden, when there is either poor epithelial resistance or increased visceral sensitivity. Reflux therefore develops via alterations in the balance of aggressive and defensive forces.

Update on Functional Heartburn

The definition of functional heartburn has been refined over the years. It is currently described, based upon Rome IV criteria, as typical heartburn symptoms in the presence of normal upper endoscopy findings (including normal biopsies), normal esophageal pH testing, and a negative association between symptoms and reflux events. Functional heartburn is very common, affecting women more than men, and with reflux hypersensitivity makes up the majority of heartburn patients who fail twice-daily proton pump inhibitor therapy. These disorders overlap with other functional gastrointestinal disorders and are often accompanied by psychological comorbidities. Diagnosis is made by using endoscopy with esophageal biopsies, wireless pH capsule, pH-impedance monitoring, and high-resolution esophageal manometry. Additional diagnostic tools that may be of value include magnification endoscopy, chromoendoscopy, narrow-band imaging, autofluorescence imaging, mucosal impedance, impedance baseline values, and histopathology scores. Functional heartburn is primarily treated with neuromodulators. Psychological intervention and complementary and alternative medicine may also play important roles in the treatment of these patients.

Classification of esophageal motor findings in gastro-esophageal reflux disease: Conclusions from an international consensus group

BACKGROUND

High-resolution manometry (HRM) has resulted in new revelations regarding the pathophysiology of gastro-esophageal reflux disease (GERD). The impact of new HRM motor paradigms on reflux burden needs further definition, leading to a modern approach to motor testing in GERD.

METHODS

Focused literature searches were conducted, evaluating pathophysiology of GERD with emphasis on HRM. The results were discussed with an international group of experts to develop a consensus on the role of HRM in GERD. A proposed classification system for esophageal motor abnormalities associated with GERD was generated.

KEY RESULTS

Physiologic gastro-esophageal reflux is inherent in all humans, resulting from transient lower esophageal sphincter (LES) relaxations that allow venting of gastric air in the form of a belch. In pathological gastro-esophageal reflux, transient LES relaxations are accompanied by reflux of gastric contents. Structural disruption of the esophagogastric junction (EGJ) barrier, and incomplete clearance of the refluxate can contribute to abnormally high esophageal reflux burden that defines GERD. Esophageal HRM localizes the LES for pH and pH-impedance probe placement, and assesses esophageal body peristaltic performance prior to invasive antireflux therapies and antireflux surgery. Furthermore, HRM can assess EGJ and esophageal body mechanisms contributing to reflux, and exclude conditions that mimic GERD.

CONCLUSIONS & INFERENCES

Structural and motor EGJ and esophageal processes contribute to the pathophysiology of GERD. A classification scheme is proposed incorporating EGJ and esophageal motor findings, and contraction reserve on provocative tests during HRM.

Intravenous Corticotropin-releasing Hormone Administration Increases Esophageal Electrical Sensitivity in Healthy Individuals

Background/Aims

When a person is experiencing stress, corticotropin-releasing hormone (CRH) can modulate gut physiologies, such as visceral sensation or gastrointestinal motility, and its intravenous administration mimics stress-induced physiological changes. However, the influence of CRH on the esophagus is yet unknown. Accordingly, we investigated whether intravenous CRH administration increases esophageal sensitivity to electrical stimulation in healthy Japanese subjects.

Methods

Twenty healthy subjects were recruited. We quantified the initial perception threshold (IPT) every 15 minutes after CRH injection. Venous blood was collected with a cannula, and both plasma adrenocorticotropic hormone (ACTH) and cortisol were measured at pre-stimulation, 0, 30, 60, 90, and 120 minutes. The results from each time point were compared against a baseline IPT obtained before electrical stimulation was initiated.

Results

When compared to the baseline IPT value (16.9 ± 4.5), CRH significantly decreased electrical threshold of the esophagus at 30, 45, 60, 75 minutes (14.1 ± 4.2, 13.1 ± 5.0, 12.1 ± 5.7, 14.0 ± 5.8 minutes, P 〈 0.01, respectively) after CRH injection, suggesting that CRH increased esophageal sensitivity to the electrical stimulus. CRH also significantly increased plasma ACTH levels at 30 minutes (50.3 ± 17.7, P 〈 0.01), and cortisol levels at 30 minutes (22.0 ± 6.7 minutes, P 〈 0.01) and 60 minutes (20.3 ± 6.7 minutes, P 〈 0.01) after CRH injection, when compared to the pre-stimulation ACTH and cortisol values.

Conclusion

Intravenous CRH administration increased esophageal electrical sensitivity in normal subjects, emphasizing the important role of stress in esophageal sensitivity.

Esophageal sensitivity to acid in patients with Barrett's esophagus is not related to preserved esophageal mucosal integrity

BACKGROUND

Patients with Barrett's esophagus (BE) usually have severe gastroesophageal reflux. However, they often have surprisingly few reflux symptoms. We hypothesized that BE patients are less sensitive to acid than gastroesophageal reflux disease (GERD) patients without Barrett and that this is due to an unusual preservation of mucosal integrity of the squamous epithelium prohibiting transepithelial acid diffusion.

METHODS

We prospectively analyzed esophageal sensitivity and esophageal mucosal integrity in GERD patients with and without BE and healthy subjects. An acid perfusion test was performed and mucosal integrity was assessed in vivo by electrical tissue impedance spectroscopy and ex vivo by Ussing chamber experiments with biopsy specimens.

KEY RESULTS

Gastroesophageal reflux disease patients with BE were less sensitive to acid than GERD patients without BE, but more sensitive to acid than healthy controls (time to perception Barrett's 14.0 minutes, GERD 4.6 minutes, controls 17.5 minutes). However, extracellular impedance (6.2 and 5.7 vs 8.4×10³  Ω/m) and transepithelial resistance (94.0 and 89 vs 118 Ω/cm² ) was similar in BE and GERD patients and significantly lower than in healthy subjects. Transepithelial fluorescein flux was equally increased in GERD patients with and without BE (1.6 and 1.7×10³ vs 0.6×10³  nmol/cm² /h).

CONCLUSIONS & INFERENCES

Esophageal hypersensitivity to acid is less pronounced in BE patients than in GERD patients without Barrett. However, mucosal integrity of the squamous epithelium is equally impaired in GERD patients with and without Barrett, indicating that factors other than esophageal mucosal barrier integrity explain the difference in acid sensitivity between those with BE and those without.

Exploration of the Esophageal Mucosal Barrier in Non-Erosive Reflux Disease

In the absence of visible mucosal damage, it is hypothesized that the esophageal mucosal barrier is functionally impaired in patients with non-erosive reflux disease (NERD). The aim of the present study was to perform an exploratory analysis of the mucosal barrier in NERD compared to erosive esophagitis (EE) and controls. A second aim was to explore TRPV1 gene transcription in relation to the mucosal barrier function and heartburn symptoms. In this prospective study, 10 NERD patients, 11 patients with active erosive esophagitis and 10 healthy volunteers were included. Biopsies from non-eroded mucosa were obtained for (1) ex vivo analyses (Ussing chamber) of transepithelial electrical resistance (TEER) and permeability (2) gene transcription of tight-junction proteins and transient receptor potential vanilloid subfamily member 1 (TRPV1). No differences in TEER or permeability were found between NERD and healthy volunteers, whereas TEER was lower in patients with erosive esophagitis. TRPV1 gene transcription was not significantly different between EE, NERD and controls. Conclusions: esophageal mucosal barrier function and TRPV1 transcription is not significantly altered in NERD patients. Future research is needed to explore other potential mechanisms that may account for the high symptom burden in these patients.

Patients with Barrett's esophagus are hypersensitive to acid but hyposensitive to other stimuli compared with healthy controls

BACKGROUND

Esophageal hyposensitivity has been observed in Barrett's esophagus and may contribute to its pathophysiology. However, studies are few, in particular those assessing different sensory modalities. We aimed to compare esophageal sensitivity to multimodal stimulation in patients with Barrett's esophagus and in healthy controls.

METHODS

Twenty-three patients with Barrett's esophagus and 12 healthy controls were examined. A multimodal probe was placed in the lower esophagus. Mechanical, thermal, and electrical stimulation was applied followed by an acid perfusion test with 0.1 N hydrochloric acid.

KEY RESULTS

Compared with controls, patients were hyposensitive to mechanical distension, heat, and electrical stimulation (all P<.05), but hypersensitive to acid (mean tolerated acid volume 57% lower, P=.001). A linear correlation between acid hypersensitivity and lower baseline impedance was found (P<.001). Patients had longer esophageal acid exposure time than controls (median acid exposure time 18 vs 5%, P=.03). Asymptomatic patients (no reflux symptoms at baseline) were hyposensitive to mechanical distension, electrical stimulation, and acid perfusion (all P<.05) compared with symptomatic patients.

CONCLUSIONS & INFERENCES

Patients with Barrett's esophagus exhibited acid hypersensitivity but hyposensitivity to other stimuli. Lower mucosal baseline impedance, a likely surrogate marker for impaired mucosal integrity, may explain the selective hypersensitivity to acid. On the other hand, the concurrent hyposensitivity may theoretically be explained by changes in central pain modulation. Patients with Barrett's esophagus seem to compose symptomatic and asymptomatic subgroups, showing different esophageal sensory profiles.

Esophageal Acid Clearance During Random Swallowing Is Faster in Patients with Barrett's Esophagus Than in Healthy Controls

Background/Aims

Impaired esophageal acid clearance may be a contributing factor in the pathogenesis of Barrett’s esophagus. However, few studies have measured acid clearance as such in these patients. In this explorative, cross-sectional study, we aimed to compare esophageal acid clearance and swallowing rate in patients with Barrett’s esophagus to that in healthy controls.

Methods

A total of 26 patients with histology-confirmed Barrett’s esophagus and 12 healthy controls underwent (1) upper endoscopy, (2) an acid clearance test using a pH-impedance probe under controlled conditions including controlled and random swallowing, and (3) an ambulatory pH-impedance measurement.

Results

Compared with controls and when swallowing randomly, patients cleared acid 46% faster (P = 0.008). Furthermore, patients swallowed 60% more frequently (mean swallows/minute: 1.90 ± 0.74 vs 1.19 ± 0.58; P = 0.005), and acid clearance time decreased with greater random swallowing rate (P < 0.001). Swallowing rate increased with lower distal esophageal baseline impedance (P = 0.014). Ambulatory acid exposure was greater in patients (P = 0.033), but clearance times assessed from the ambulatory pH-measurement and acid clearance test were not correlated (all P > 0.3).

Conclusions

More frequent swallowing and thus faster acid clearance in Barrett’s esophagus may constitute a protective reflex due to impaired mucosal integrity and possibly acid hypersensitivity. Despite these reinforced mechanisms, acid clearance ability seems to be overthrown by repeated, retrograde acid reflux, thus resulting in increased esophageal acid exposure and consequently mucosal changes.

Prevalence, characteristics, and treatment outcomes of reflux hypersensitivity detected on pH-impedance monitoring

BACKGROUND

Positive symptom association probability (SAP) with physiologic esophageal acid exposure time (AET) on pH-impedance monitoring defines reflux hypersensitivity (RH), a correlate of acid sensitivity on pH monitoring. We evaluated prevalence, clinical characteristics, and symptomatic outcomes of RH in a prospective observational cohort with reflux symptoms undergoing pH-impedance monitoring.

METHODS

Reflux hypersensitivity was diagnosed when SAP was positive with pH- and/or impedance-detected reflux events with physiologic AET. Symptom burden was assessed using dominant symptom intensity (DSI, product of symptom severity and frequency on 5-point Likert scales) and global symptom severity (GSS, global esophageal symptoms on 100-mm visual analog scales) by questionnaire, both at baseline and on prospective follow-up. Clinical characteristics and predictors of symptomatic improvement were assessed with univariate and multivariate analyses.

KEY RESULTS

Seventy-seven patients (29%) met criteria for RH, of which 53 patients (53.7 ± 1.8 years, 66% F) were contacted after 3.3 ± 0.2 years for follow-up. Reflux hypersensitivity was detected on pH-impedance testing both on and off antisecretory therapy; pH alone missed 51% of RH. About 57% reported ≥50% GSS improvement. Sixteen patients undergoing antireflux surgery (ARS) reported better symptom improvement compared to 37 patients treated medically (GSS change: p = 0.005; DSI change: p = 0.04). Hiatus hernia (p = 0.03) and surgical management (p ≤ 0.04) predicted symptom improvement on univariate analysis, while acid sensitivity was a negative predictor for outcome on both univariate (p = 0.02) and multivariate analyses (p ≤ 0.04).

CONCLUSIONS & INFERENCES

Reflux hypersensitivity is a mechanism for persistent reflux symptoms in almost one-third of patients undergoing pH-impedance testing. While acid sensitivity predicts suboptimal symptom improvement, antireflux therapy may improve RH in select settings.

Characteristics of symptomatic reflux episodes in Japanese proton pump inhibitor-refractory non-erosive reflux disease patients

AIM

To clarify the pathogenesis of gastroesophageal reflux disease symptoms in non-erosive reflux disease (NERD) patients.

METHODS

Thirty-five NERD patients with persistent symptoms, despite taking rabeprazole 10 mg twice daily for at least 8 wk, were included in this study. All patients underwent 24 h combined impedance - pH on rabeprazole. The symptom index (SI) was considered to be positive if ≥ 50%, and proximal reflux episodes were determined when reflux reached 15 cm above the proximal margin of the lower esophageal sphincter.

RESULTS

In 14 (40%) SI-positive patients, with liquid weakly acid reflux, the occurrence rate of reflux symptoms was significantly more frequent in proximal reflux episodes (46.7%) than in distal ones (5.7%) (P < 0.001). With liquid acid reflux, there were no significant differences in the occurrence rate of reflux symptoms between proximal reflux episodes (38.5%) and distal ones (20.5%) (NS). With mixed liquid-gas weakly acid reflux, the occurrence rate of reflux symptoms in proximal reflux episodes was significantly more frequent (31.0%) than in distal reflux ones (3.3%) (P < 0.001). With mixed liquid-gas acid reflux, there were no significant differences in the occurrence rate of reflux symptoms between proximal reflux episodes (29.4%) and distal ones (14.3%) (NS).

CONCLUSION

The proximal extent of weakly acidic liquid and mixed liquid-gas reflux is a major factor associated with reflux perception in SI-positive patients on proton pump inhibitor therapy.

Protease-Activated Receptor-2 Up-Regulates Transient Receptor Potential Vanilloid 4 Function in Mouse Esophageal Keratinocyte

BACKGROUND

The reflux of pancreatic-duodenal fluids is implicated in the pathophysiology of proton-pump inhibitor-resistant gastroesophageal reflux disease (GERD). Protease-activated receptor-2 (PAR-2) is activated by proteases, the pancreatic enzyme, trypsin, and the activated PAR-2 enhances transient receptor potential vanilloid 4 (TRPV4) function in neurons. TRPV4 stimulates ATP exocytosis in conjunction with the vesicular nucleotide transporter, which mediates mechano-transduction and vagal stimulation. The aim of the present study was to verify whether the activated PAR-2 up-regulates TRPV4 function in mouse esophageal keratinocytes, which may link to the pathophysiology in PPI-resistant GERD.

METHODS

TRPV4 and PAR-2 expressions were detected by RT-PCR, immunostaining, and western blotting in mouse esophageal keratinocytes. The functional response of TRPV4 to esophageal keratinocytes was analyzed using a Ca(2+) imaging system. Cellular ATP release was examined by luciferase-luciferin reaction. TRPV4 phosphorylation was studied by immunoprecipitation and western blotting.

RESULTS

PAR-2 and TRPV4 mRNAs and proteins were expressed in esophageal keratinocytes. Pre-treatment with trypsin significantly increased the responses to TRPV4 activator in esophageal keratinocytes, probably via the phosphorylation of serine residue of TRPV4 by protein kinase C and resulted in cellular ATP release from the cells.

CONCLUSIONS

Activated PAR-2 with trypsin exposure up-regulated TRPV4 function and increased ATP release in mouse esophageal keratinocytes. This mechanism might be related to the pathophysiology of GERD, especially non-erosive GERD.

Pathophysiology of gastroesophageal reflux disease: new understanding in a new era

BACKGROUND

The prevalence of gastroesophageal reflux disease (GERD) has increased in the last decades and it is now one of the most common chronic diseases. Throughout time our insight in the pathophysiology of GERD has been characterized by remarkable back and forth swings, often prompted by new investigational techniques. Even today, the pathophysiology of GERD is not fully understood but it is now recognized to be a multifactorial disease. Among the factors that have been shown to be involved in the provocation or increase of reflux, are sliding hiatus hernia, low lower esophageal sphincter pressure, transient lower esophageal sphincter relaxation, the acid pocket, obesity, increased distensibility of the esophagogastric junction, prolonged esophageal clearance, and delayed gastric emptying. Moreover, multiple mechanisms influence the perception of GERD symptoms, such as the acidity of the refluxate, its proximal extent, the presence of gas in the refluxate, duodenogastroesophageal reflux, longitudinal muscle contraction, mucosal integrity, and peripheral and central sensitization. Understanding the pathophysiology of GERD is important for future targets for therapy as proton pump inhibitor-refractory GERD symptoms remain a common problem.

PURPOSE

In this review we provide an overview of the mechanisms leading to reflux and the factors influencing perception, in the light of historical developments. It is clear that further research remains necessary despite the recent advances in the understanding of the pathophysiology of GERD.

Diagnosis of Gastroesophageal Reflux Disease Using Real-time Magnetic Resonance Imaging

A small angle (His angle) between the oesophagus and the fundus of the stomach is considered to act as flap valve and anti-reflux barrier. A wide angle results in dysfunction of the oesophagogastric junction and subsequently in gastroesophageal reflux disease (GERD). Here, we used real-time magnetic resonance imaging (MRI) at 50 ms resolution (20 frames per second) in 12 volunteers and 12 patients with GERD to assess transport of pineapple juice through the oesophagogastric junction and reflux during Valsalva. We found that the intra-abdominal part of the oesophagus was bended towards the left side resulting in an angle of 75.3 ± 17.4, which was significantly larger during Valsava (P = 0.017). Reflux and several underlying pathologies were detected in 11 out of 12 patients. Our data visualize oesophagogastric junction physiology and disprove the flap valve hypothesis. Further, non-invasive real-time MRI has considerable potential for the diagnosis of causative pathologies leading to GERD.

[Some issues of the diagnosis and treatment of gastroesophageal reflux disease]

The clinical inefficacy of proton pump inhibitors (PPIs) is very frequently encountered in nonerosive gastroesophageal reflux disease (NERD) in particular. Postprandial acid pocket, weak-acid or alkaline reflux, etc. are one of the causes of resistance to antisecretory drugs. Alginates serve as a good alternative to PPIs in treating NERD and gastroesophageal reflux in children and pregnant women. The alginate test may help diagnose NERD.

Increased proximal reflux in a hypersensitive esophagus might explain symptoms resistant to proton pump inhibitors in patients with gastroesophageal reflux disease

BACKGROUND & AIMS

Approximately 30% of patients with gastroesophageal reflux disease have symptoms resistant to treatment with proton pump inhibitors (PPIs). Several mechanisms such as esophageal hypersensitivity, increased mucosal permeability, and possibly the position of the gastric acid pocket might underlie a partial response to PPIs. To what extent these mechanisms interact and contribute to PPI-resistant symptoms, however, has not been investigated previously.

METHODS

In 18 gastroesophageal reflux disease patients (9 PPI responders and 9 PPI partial responders), esophageal sensitivity, mucosal permeability, and postprandial reflux parameters were determined during PPI use. Esophageal sensitivity for distension was measured by gradual balloon inflation at 5 and 15 cm above the lower esophageal sphincter. The mucosal permeability of 4 esophageal biopsy specimens per patient was determined in Ussing chambers by measuring the transepithelial electrical resistance and transmucosal flux of fluorescein. Postprandial reflux parameters were determined using concurrent high-resolution manometry/pH impedance after a standardized meal. In addition, the acid pocket was visualized using scintigraphy.

RESULTS

No difference in the rate of postprandial acid reflux, in the pH of the acid pocket (PPI responders 3.7 ± 0.7 vs PPI partial responders 4.2 ± 0.4; P = .54), or in the position of the acid pocket was observed in PPI partial responders compared with PPI responders. In addition, the permeability of the esophageal mucosa was similar in both groups, as shown by a similar transepithelial electrical resistance and flux of fluorescein. PPI partial responders had more reflux episodes with a higher mean proximal extent, compared with PPI responders, and were more sensitive to balloon distension, both in the upper and lower esophagus.

CONCLUSIONS

PPI-resistant symptoms most likely are explained by increased proximal reflux in a hypersensitive esophagus and less likely by increased mucosal permeability or the position of the acid pocket.

Gastroesophageal reflux symptoms not responding to proton pump inhibitor: GERD, NERD, NARD, esophageal hypersensitivity or dyspepsia?

Gastroesophageal reflux (GER) is a common gastrointestinal process that can generate symptoms of heartburn and chest pain. Proton pump inhibitors (PPIs) are the gold standard for the treatment of GER; however, a substantial group of GER patients fail to respond to PPIs. In the past, it was believed that acid reflux into the esophagus causes all, or at least the majority, of symptoms attributed to GER, with both erosive esophagitis and nonerosive outcomes. However, with modern testing techniques it has been shown that, in addition to acid reflux, the reflux of nonacid gastric and duodenal contents into the esophagus may also induce GER symptoms. It remains unknown how weakly acidic or alkaline refluxate with a pH similar to a normal diet induces GER symptoms. Esophageal hypersensitivity or functional dyspepsia with superimposed heartburn may be other mechanisms of symptom generation, often completely unrelated to GER. Detailed studies investigating the pathophysiology of esophageal hypersensitivity are not conclusive, and definitions of the various disease states may overlap and are often confusing. The authors aim to clarify the pathophysiology, definition, diagnostic techniques and medical treatment of patients with heartburn symptoms who fail PPI therapy.

Impairment of secondary peristalsis in Barrett’s esophagus by transnasal endoscopy-based testing

AIM: To investigate dysfunctions in esophageal peristalsis and sensation in patients with Barrett’s esophagus following acid infusion using endoscopy-based testing.

METHODS: First, physiological saline was infused into the esophagus of five healthy subjects, at a rate of 10 mL/min for 10 min, followed by infusion of HCl. Esophageal contractions were analyzed to determine whether the contractions observed by endoscopy and ultrasonography corresponded to the esophageal peristaltic waves diagnosed by manometry. Next, using nasal endoscopy, esophageal sensations and contractions were investigated in patients with, as well as controls without, Barrett’s esophagus using the same infusion protocol.

RESULTS: All except one of the propulsive contractions identified endoscopically were recorded as secondary peristaltic waves by manometry. Patients with long segment Barrett’s esophagus (LSBE) tended to have a shorter lag time than the control group, although the difference did not reach statistical significance (88 ± 54 s vs 162 ± 150 s respectively, P = 0.14). Furthermore, patients with LSBE had significantly fewer secondary contractions following the infusion of both saline and HCl than did either the control group or patients with short segment Barrett’s esophagus (4.1 ± 1.2 vs 8.0 ± 2.8, P < 0.001 and 7.3 ± 3.2, P < 0.01, respectively, following saline infusion; 5.3 ± 1.2 vs 8.4 ± 2.4 and 8.1 ± 2.9 respectively, P < 0.01 for both, following infusion of HCl).

CONCLUSION: Using nasal endoscopy and a simple acid-perfusion study, we were able to demonstrate disorders in secondary peristalsis in patients with LSBE.

Acid reflux episodes sensitize the esophagus to perception of weakly acidic and mixed reflux in non-erosive reflux disease patients

BACKGROUND

Non-erosive reflux disease (NERD) patients are more sensitive than erosive esophagitis patients to weakly acidic reflux and to the presence of gas in the refluxate. Intra-esophageal acid perfusion sensitizes esophageal receptors to mechanical and chemical stimuli.

METHODS

To establish whether acid sensitization plays a role in the perception of weakly acidic and mixed reflux episodes, 29 NERD patients, responders and 14 non-responders to proton pump inhibitors (PPIs), underwent pH-impedance monitoring. Non-responders repeated the study while on PPIs. To assess the effect of acid exposure on symptom perception, the time period with pH below 4 was measured in 15- and 30-minute time-windows preceding the onset of each reflux episode.

KEY RESULTS

Considering weakly acidic and mixed refluxes, both in responder and non-responder patients (off PPIs), the symptomatic refluxes were preceded by a significantly higher cumulative acid exposure than the asymptomatic refluxes. In all patients, following acid reflux, the percentage of symptomatic weakly acidic reflux episodes was significantly higher than that of asymptomatic refluxes. Non-responder patients, off-treatment, were characterized by a lower proportion of weakly acidic reflux and mixed reflux episodes. In the non-responder patients on PPI, only mixed and weakly symptomatic reflux episodes were preceded by a higher cumulative acid exposure.

CONCLUSIONS & INFERENCES

In NERD patients, spontaneous acid reflux enhances subsequent reflux perception, regardless of acidity or liquid/mixed composition of episodes; in non-responder patients on PPIs, only the perception of mixed and weakly acidic reflux episodes seems to be mediated by a preceding acid exposure.

Gastroesophageal reflux disease: Update on inflammation and symptom perception

Although gastroesophageal reflux disease (GERD) is a common disorder in Western countries, with a significant impact on quality of life and healthcare costs, the mechanisms involved in the pathogenesis of symptoms remain to be fully elucidated. GERD symptoms and complications may result from a multifactorial mechanism, in which acid and acid-pepsin are the important noxious factors involved. Prolonged contact of the esophageal mucosa with the refluxed content, probably caused by a defective anti-reflux barrier and luminal clearance mechanisms, would appear to be responsible for macroscopically detectable injury to the esophageal squamous epithelium. Receptors on acid-sensitive nerve endings may play a role in nociception and esophageal sensitivity, as suggested in animal models of chronic acid exposure. Meanwhile, specific cytokine and chemokine profiles would appear to underlie the various esophageal phenotypes of GERD, explaining, in part, the genesis of esophagitis in a subset of patients. Despite these findings, which show a significant production of inflammatory mediators and neurotransmitters in the pathogenesis of GERD, the relationship between the hypersensitivity and esophageal inflammation is not clear. Moreover, the large majority of GERD patients (up to 70%) do not develop esophageal erosions, a variant of the condition called non-erosive reflux disease. This summary aims to explore the inflammatory pathway involved in GERD pathogenesis, to better understand the possible distinction between erosive and non-erosive reflux disease patients and to provide new therapeutic approaches.

Role of nociceptors/neuropeptides in the pathogenesis of visceral hypersensitivity of nonerosive reflux disease

BACKGROUND AND AIMS

Esophageal visceral hypersensitivity has been proposed to be a pathogenesis of heartburn in nonerosive reflux disease (NERD), but its further mechanisms are unclear. Recently, it has been suggested that nociceptors and neuropeptides control sensory and pain mechanisms. Therefore, the objective of the present study was to estimate expression of acid-sensitive nociceptors such as transient receptor potential vanilloid 1 (TRPV1) and acid-sensing ion channel 3, protease-activated receptor 2 (PAR2), neuropeptides such as substance P and calcitonin-gene-related peptide, and their receptors such as neurokinin 1 receptor (NK1R) and receptor activity-modifying protein 1 in the esophageal mucosa of NERD patients.

METHODS

Biopsy samples were taken from NERD patients and healthy control subjects without heartburn. The expression level of nociceptors, neuropeptides, and their receptors were assessed by real-time RT-PCR and enzyme immunoassay. Localization of substance P and CGRP in the esophageal mucosa was determined by immunohistochemical staining.

RESULTS

Expression of mRNA for TRPV1 and PAR2 was significantly elevated in the esophageal mucosa of NERD patients. Substance P protein level and its receptor NK1R mRNA also increased in NERD patients. A positive correlation between the substance P protein level and reflux symptoms was observed. Immunohistochemical study revealed the presence of substance P-positive nerves in the lamina propria of the esophagus.

CONCLUSIONS

These findings suggest that visceral hypersensitivity in NERD patients is involved in neurogenic inflammation showing the increase in both substance P release and NK1R expression, which may be associated with the activation of TRPV1 and PAR2.

Acid sensitization of esophageal mucosal afferents: implication for symptom perception in patients across the gastroesophageal reflux disease spectrum

BACKGROUND

Sensitization of esophageal chemoreceptors, either directly by intermittent acid exposure or indirectly through esophagitis-associated inflammatory mediators, is likely to be the mechanism underlying the perception of heartburn.

AIMS

To compare basal esophageal sensitivity with electrical stimulation and acid, and to compare the degree of acid-induced sensitization in controls and in patient groups across the entire spectrum of gastroesophageal reflux disease: erosive oesophagitis (EO), nonerosive reflux disease (NERD), and functional heartburn (FH).

METHODS

Esophageal sensory and pain thresholds to electrical stimulation were measured before, 30, and 60 minutes after an intraesophageal infusion of saline or HCl. Patients received a 30-minute infusion of 0.15 M HCl and controls were randomized to receive either HCl (n = 11) or saline (n = 10). After electrical sensory threshold testing, participants received another 30-minute infusion of HCl to determine whether sensitivity to acid is increased by prior acid exposure

RESULTS

All patient groups had higher basal sensory thresholds than healthy controls (controls, 13 ± 1.4 mA; FH, 20 ± 5.1 mA; NERD, 21 ± 5.1 mA; EO, 23 ± 5.4 mA; P < 0.05). Acute esophageal acid exposure reduced sensory thresholds to electrical stimulation in FH and NERD patients (P < 0.05). The level of acid sensitivity during the first HCl infusion was comparable between all patient groups and controls. The secondary infusion caused increased discomfort in all participants (P < 0.01). This acid-induced sensitization to HCl was significantly elevated in the patient groups ( P < 0.05).

CONCLUSIONS

(1) Esophageal acid infusion sensitizes it to subsequent electrical and chemical stimulation. (2) The acid-related sensitization is greater in gastroesophageal reflux disease than in controls and may influence in part symptom perception in this population. (3) Acid-related sensitization within the gastroesophageal reflux disease population is not dependant on mucosal inflammation.

How reflux causes symptoms: reflux perception in gastroesophageal reflux disease

In gastroesophageal reflux disease (GERD) symptoms arise due to reflux of gastric content into the oesophagus. However, the relation between magnitude and onset of reflux and symptom generation in GERD patients is far from simple; gastroesophageal reflux occurs several times a day in everyone and the majority of reflux episodes remains asymptomatic. This review aims to address the question how reflux causes symptoms, focussing on factors leading to enhanced reflux perception. We will highlight esophageal sensitivity variance between subtypes of GERD, which is influenced by peripheral sensitization of primary afferents, central sensitization of spinal dorsal horn neurons, impaired mucosal barrier function and genetic factors. We will also discuss the contribution of specific refluxate characteristics to reflux perception, including acidity, and the role of bile, pepsin and gas and proximal extent. Further understanding of reflux perception might improve GERD treatment, especially in current partial responders to therapy.

Gastro-oesophageal reflux disease

Gastro-oesophageal reflux disease is one of the most common disorders of the gastrointestinal tract. Over past decades, considerable shifts in thinking about the disease have taken place. At a time when radiology was the only diagnostic test available, reflux disease was regarded as synonymous with hiatus hernia. After the advent of the flexible endoscope, reflux disease was, for a period, equated to oesophagitis. The introduction of oesophageal pH monitoring made us believe that reflux disease could be defined by an abnormally high proportion of time with oesophageal pH less than 4. Moreover, the successive arrival of histamine-2-receptor antagonists and proton-pump inhibitors changed our idea of treatment for the disease, with swings from and towards surgery, endoscopic techniques, and alternative pharmaceutical options.

NERD: an umbrella term including heterogeneous subpopulations

Nonerosive reflux disease (NERD) represents the more common phenotypic presentation of GERD and comprises patients who have typical symptoms without any mucosal breaks at endoscopy. However, these patients are markedly heterogeneous from a pathophysiological point of view and should be correctly classified by means of 24 h impedance-pH testing, which enables detection of both acidic and weakly acidic reflux and correlation with symptoms. This technique is able to identify two subsets of NERD (that is, patients with an excess of acid or with a hypersensitive oesophagus to both acid and weakly acidic reflux) and patients with functional heartburn (who do not have any kind of reflux underlying their symptoms and must be excluded from the realm of GERD). The mechanisms of symptom generation are not clear in patients with NERD, but the presence of microscopic oesophagitis, including the dilation of intercellular spaces, seems to have a relevant role. Patients with NERD in whom acid is the main pathogenetic factor respond successfully to PPI therapy, while those with hypersensitive oesophagus to weakly acidic reflux need to be treated with reflux inhibitors or surgery, although the experience in this field is very scant. Patients with functional heartburn should undergo therapy with pain modulators, but large placebo-controlled trials are necessary.

Managing Barrett's esophagus with radiofrequency ablation

Barrett's esophagus (BE) is a well-established pre-malignant lesion for esophageal adenocarcinoma, a condition that carries a dismal five-year overall survival rate of less than 15%. Among several available methods to eliminate BE, radiofrequency ablation (RFA) provides the most efficient modality, since it has been demonstrated to successfully eradicate BE with or without dysplasia with acceptable safety, efficacy and durability profiles. In conjunction with proton pump therapy, this new technology has quickly become the standard care for patients with dysplastic BE. However, several technical questions remain about how to deploy RFA therapy for maximum effectiveness and long-term favorable outcomes for all stages of the disease. These include how to select patient for therapy, what the best protocol for RFA is, when to use other modalities, such as endoscopic mucosal resection, and what should be considered for refractory BE. This review addresses these questions with the perspective of the best available evidence matched with the authors' experience with the technology.

Comparison of gastroesophageal reflux disease symptoms and proton pump inhibitor response using gastroesophageal reflux disease impact scale questionnaire

Background/Aims

To compare gastroesophageal reflux disease (GERD) symptoms and response to proton pump inhibitor (PPI) in patients with erosive esophagitis (EE), non-erosive reflux disease (NERD) or functional heartburn (FH) using GERD impact scale (GIS) questionnaire.

Methods

Total 126 patients with GERD symptoms were diagnosed as EE (n = 62), NERD (n = 34) and FH (n = 30) by endoscopy, 24-hour esophageal pH testing and Bernstein test, prospectively. Analysis of risk factors and GIS questionnaire for GERD symptoms and quality of life were performed before and 8 weeks after PPI treatment.

Results

EE group had a higher proportion of men, frequent alcohol consumption, smoking, hiatal hernia, body mass index ≥ 25 kg/m² and triglyceride levels (≥ 150 mg/dL) than the other groups (all P < 0.05). On the other hand, both psychiatric treatment and psychopharmacotherapy were more frequent in patients with FH than in those with EE and NERD (both P < 0.05). Among GERD symptoms, chest pain was more frequent in FH group than in EE and NERD groups (P < 0.05). Eating problems and limitation of productive daily activities occurred frequently in FH group and NERD group, respectively. GIS after 8 week PPI treatment showed improvement in all of the GERD symptoms in EE (all P < 0.05) and in acid regurgitation, epigastric pain and hoarseness in NERD group (all P < 0.05). In terms of quality of life, PPI treatment improved sleep disturbance in EE (P = 0.031) and limitation of productive activity in the NERD group (P = 0.001).

Conclusions

GIS questionnaire showed that different characteristics and symptoms improved after PPI therapy among patients with EE, NERD and FH, demonstrating the usefulness of the GIS questionnaire.

Efficacy of endoluminal gastroplication in Japanese patients with proton pump inhibitor-resistant, non-erosive esophagitis

AIM: To evaluate the efficacy, safety, and long-term outcomes of endoluminal gastroplication (ELGP) in patients with proton pump inhibitor (PPI)-resistant, non-erosive reflux disease (NERD).

METHODS: The subjects were NERD patients, diagnosed by upper endoscopy before PPI use, who had symptoms such as heartburn or reflux sensations two or more times a week even after 8 wk of full-dose PPI treatment. Prior to ELGP, while continuing full-dose PPI medication, patients’ symptoms and quality of life (QOL) were assessed using the questionnaire for the diagnosis of reflux disease, the frequency scale for symptoms of gastro-esophageal reflux disease (FSSG), gastrointestinal symptoms rating scale, a 36-item short-form. In addition, 24-h esophageal pH monitoring or 24-h intraesophageal pH/impedance (MII-pH) monitoring was performed. The Bard EndoCinch^TM was used for ELGP, and 2 or 3 plications were made. After ELGP, all acid reducers were temporarily discontinued, and medication was resumed depending on the development and severity of symptoms. Three mo after ELGP, symptoms, QOL, pH or MII-pH monitoring, number of plications, and PPI medication were evaluated. Further, symptoms, number of plications, and PPI medication were evaluated 12 mo after ELGP to investigate long-term effects.

RESULTS: The mean FSSG score decreased significantly from before ELGP to 3 and 12 mo after ELGP (19.1 ± 10.5 to 10.3 ± 7.4 and 9.3 ± 9.9, P < 0.05, respectively). The total number of plications decreased gradually at 3 and 12 mo after ELGP (2.4 ± 0.8 to 1.2 ± 0.8 and 0.8 ± 1.0, P < 0.05, respectively). The FSSG scores in cases with no remaining plications and in cases with one or more remaining plications were 4.4 and 2.7, respectively, after 3 mo, and 2.0 and 2.8, respectively, after 12 mo, showing no correlation to plication loss. On pH monitoring, there was no difference in the percent time pH < 4 from before ELGP to 3 mo after. Impedance monitoring revealed no changes in the number of reflux episodes or the symptom index for reflux events from before ELGP to 3 mo after, but the symptom sensitivity index decreased significantly 3 mo after ELGP (16.1 ± 12.9 to 3.9 ± 8.3, P < 0.01). At 3 mo after ELGP, 6 patients (31.6%) had reduced their PPI medication by 50% or more, and 11 patients (57.9%) were able to discontinue PPI medication altogether. After 12 mo, 3 patients (16.7%) were able to reduce the amount of PPI medication by 50% or more, and 12 patients (66.7%) were able to discontinue PPI medication altogether. A high percentage of cases with remaining plications had discontinued PPIs medication after 3 mo, but there was no difference after 12 mo. No serious complications were observed in this study.

CONCLUSION: ELGP was safe, resulted in significant improvement in subjective symptoms, and allowed less medication to be used over the long term in patients with PPI-refractory NERD.

Effective intra-esophageal acid control is associated with improved radiofrequency ablation outcomes in Barrett's esophagus

BACKGROUND

Endoscopic radiofrequency ablation (RFA) is a promising new treatment of Barrett's esophagus (BE). Adjunctive intra-esophageal pH control with proton pump inhibitors and/or anti-reflux surgery is generally recommended to optimize squamous re-epithelialization after ablation.

AIMS

The aims of this study were to examine the association between intra-esophageal pH control and RFA outcomes and to identify predictive factors to achieve complete elimination (CE) of BE following RFA.

METHODS

We retrospectively studied the outcomes of BE patients treated with RFA. Esophageal acid exposure (EAE) was assessed utilizing 24-h pH monitoring on therapy. CE was endoscopically defined as no area suspicious for residual metaplasia following RFA.

RESULTS

Of 45 patients (33 men; mean age 61.6, mean BE length C4.1 M4.6) examined for EAE, 29 % exhibited moderate-severe EAE despite therapy. Reduction in BE surface area and CE rate were higher in the normal-mild EAE group compared with the moderate-severe EAE group (99 vs. 95 %, p = 0.02; 44 vs. 15 %, p = 0.09, respectively). Using univariate analysis, age, gender, race, aspirin/NSAIDs use, baseline worst histology, baseline BE surface area, and the number or types of RFA had no correlation with CE. By multivariate multiple logistic regression analysis, normal-mild EAE and smaller hiatal hernia were independent factors associated with CE.

CONCLUSIONS

Effective intra-esophageal pH control is associated with improved RFA outcomes of BE. Normal to mild EAE and smaller hiatal hernia are predictive factors to achieve CE. Given the frequent persistence of acid reflux despite therapy in BE patients, in order to maximize the RFA effects esophageal pH optimization and hernia repair should be considered.

Natural history of Barrett's esophagus

The natural history of Barrett’s esophagus (BE) is difficult to quantify because, by definition, it should describe the course of the condition if left untreated. Pragmatically, we assume that patients with BE will receive symptomatic treatment with acid suppression, usually a proton pump inhibitor, to treat their heartburn. This paper describes the development of complications of stricture, ulcer, dysplasia and adenocarcinoma from this standpoint. Controversies over the definition of BE and its implications in clinical practice are presented. The presence of intestinal metaplasia and its relevance to cancer risk is discussed, and the need to measure the extent of the Barrett’s epithelium (long and short segments) using the Prague guidelines is emphasized. Guidelines and international consensus over the diagnosis and management of BE are being regularly updated. The need for expert consensus is important due to the lack of randomized trials in this area. After searching the literature, we have tried to collate the important studies regarding progression of Barrett’s to dysplasia and adenocarcinoma. No therapeutic studies yet reported show a clear reduction in the development of cancer in BE. The effect of pharmacological and surgical intervention on the natural history of Barrett’s is a subject of ongoing research, including the Barrett’s Oesophagus Surveillance Study and the aspirin and esomeprazole cancer chemoprevention trial with interesting results. The geographical variation and the wide range of outcomes highlight the difficulty of providing an individualized risk profile to patients with BE. Future studies on the interaction of genome wide abnormalities in Barrett’s and their interaction with environmental factors may allow individualization of the risk of cancer developing in BE.

Esophageal motor disorders: how to bridge the gap between advanced diagnostic tools and paucity of therapeutic modalities?

High-resolution manometry has added significantly to our current understanding of esophageal motor function by providing improved detail and a data analysis paradigm that is more akin to an imaging format. Esophageal pressure topography provides a seamless dynamic representation of the pressure profile through the entire esophagus and thus, is able to eliminate movement artifact and also assess intrabolus pressure patterns as a surrogate for bolus transit mechanics. This has led to improved identification of anatomic landmarks and measurement of important physiological parameters (esophagogastric junction relaxation, distal latency, and contractile integrity). This research has bridged the gap into clinical practice by defining physiologically relevant phenotypes that may have prognostic significance and improve treatment decisions in achalasia, spasm, and hypercontractile disorders. However, more work is needed in determining the etiology of symptom generation in the context of normal or trivial motor dysfunction. This research will require new techniques to assess visceral hypersensitivity and alterations in central modulation of pain and discomfort.