The pathogenesis of heartburn in nonerosive reflux disease: a unifying hypothesis

Human leukocyte antigen HLADRB1 determinants susceptibility to gastroesophageal reflux disease

BACKGROUND

- Gastroesophageal reflux disease (GERD) is characterized by diverse symptoms. There is an evidence for a genetic component to GERD as supported by familial aggregation of this disease.

OBJECTIVE

- To investigate whether certain human leucocyte antigen genes HLA-DRB1 are associated with GERD.

METHODS

- Patients and controls were prospectively recruited from GIT center at Al-Kindy Teaching Hospital (Baghdad-Iraq) between January 2014 and July 2016. Sixty Iraqi Arab Muslims patients with a history of heartburn and dyspepsia compared with 100 Iraqi Arab Muslims controls. All study patients and control groups underwent upper gastrointestinal endoscopic examinations and their serums were analyzed for CagA antibodies Immunoglobulin G (IgG) for H. pylori. HLA-DRB1 genotyping were done to both groups.

RESULTS

- A total of 60 patients with erosive gastritis; GERD (Grade II and III) were evaluated, together with 100 controls. There is a significant increase of H. pylori infection (P=0.0001) in GERD patients than control group. HLA-DRB1* 15:01 was significantly increased in GERD patients in comparison with control group and an increased frequency of HLADRB1*11:01 in control group compared with patients group.

CONCLUSION

- There is an association between HLA-DRB1 *15:01 in GERD patients with H. pylori positive patients.

Esophageal mucosal integrity improves after laparoscopic antireflux surgery in children with gastroesophageal reflux disease

Background

Esophageal intraluminal baseline impedance reflects the conductivity of the esophageal mucosa and may be an instrument for in vivo evaluation of mucosal integrity in children with gastroesophageal reflux disease (GERD). Laparoscopic antireflux surgery (LARS) is a well-established treatment option for children with proton pump inhibitory (PPI) therapy resistant GERD. The effect of LARS in children on baseline impedance has not been studied in detail. The aim of this study was to evaluate the effect of LARS on baseline impedance in children with GERD.

Methods

This is a prospective, multicenter, nationwide cohort study (Dutch national trial registry: NTR2934) including 25 patients [12 males, median age 6 (range 2–18) years] with PPI-resistant GERD scheduled to undergo LARS. Twenty-four hour multichannel intraluminal impedance pH monitoring (MII-pH monitoring) was performed before and 3 months after LARS. Baseline impedance was evaluated during consecutive 2-h intervals in the 24-h tracings.

Results

LARS reduced acid exposure time from 8.5 % (6.0–16.2 %) to 0.8 % (0.2–2.8 %), p < 0.001. Distal baseline impedance increased after LARS from 2445 Ω (1147–3277 Ω) to 3792 Ω (3087–4700 Ω), p < 0.001. Preoperative baseline impedance strongly correlated with acid exposure time (r −0.76, p < 0.001); however, no association between symptomatic outcome and baseline impedance was identified.

Conclusions

LARS significantly increased baseline impedance likely reflecting recovery of mucosal integrity. As the change in baseline impedance was not associated with the clinical outcome of LARS, other factors besides mucosal integrity may contribute to symptom perception in children with GERD.

The diagnostic value of 24-hour ambulatory intraesophageal pH-impedance in patients with laryngopharyngeal reflux symptoms comparable with typical symptoms

BACKGROUND

The diagnosis of laryngopharyngeal reflux is currently based on a combination of the patient history of multichannel intraluminal impedance and ambulatory pH (MII-pH); however, none of these findings alone is specific for the diagnosis of laryngopharyngeal reflux. We aimed to compare the baseline characteristics and esophageal baseline impedance values between patients with and without laryngopharyngeal reflux symptoms.

METHODS

We retrospectively analyzed data from two groups of patients with laryngopharyngeal reflux according to their reflux finding score (RFS) as scored by ENTs. Control patients were nonerosive reflux disease patients without laryngopharyngeal reflux. All MII-pH parameters and baseline impedance were analyzed from six levels and the proximal and distal baseline impedance and the ratio of the proximal to distal baseline impedance levels was calculated.

RESULTS

Altogether 123 patients with laryngopharyngeal reflux and 49 control patients were included. A total of 81 of 123 patients had RFS ≥ 7, and 42 of 123 patients had RFS < 7. Baseline impedance analysis showed that patients with laryngopharyngeal reflux symptoms had significantly lower proximal baseline impedance values (1997 ± 51 vs 2245 ± 109, p < 0.05) than the control group. Additionally, patients with laryngopharyngeal reflux symptoms had a significantly lower proximal-to-distal ratio (1.28 ± 0.05 vs 1.53 ± 0.09, p < 0.05). In the subgroup analysis, patients with RFS < 7 were found to have a significantly lower acid exposure time than either the patients with RFS ≥ 7 (3.85 ± 0.65 vs 8.2 ± 1.52, p < 0.05) or the control group (3.85 ± 0.65 vs 6.1 ± 0.81, p < 0.05). Additionally, patients with RFS ≥ 7 had significantly lower proximal baseline impedance levels than the control group (1970 ± 63 vs 2245 ± 109, p < 0.05).

CONCLUSIONS

Patients with pathologic laryngopharyngeal reflux symptom scores had lower proximal baseline impedance levels and lower proximal-to-distal ratios, which may reflect the proximal mucosal noxious effect of the refluxate. These results may indicate that laryngopharyngeal reflux symptoms may be due to chronic acid exposure in the proximal segments of the esophagus, and the proximal-to-distal ratio may be used as a new metric for diagnosis.

Factors associated with nonresponse to proton pump inhibitors therapy in patients referred for esophageal pH-impedance monitoring

Nonresponse to proton pump inhibitors (PPI) concerns up to 40% of patients treated for gastroesophageal reflux disease (GERD). Identifying predictive factors of nonresponse might help to optimize patients' treatment. The aim of this study was to determine clinical factors associated with nonresponse to PPI therapy in patients referred for pH-impedance monitoring. One hundred and sixty-eight consecutive patients (105 females, mean age 52 years, range 17-83) were included between October 2011 and May 2013. Before the realization of high-resolution manometry and 24-hour pH-impedance monitoring they completed a questionnaire including Rome III criteria for functional dyspepsia and irritable bowel syndrome (IBS). Comparisons between patients with and without PPI response were performed using chi-square or analysis of variance tests. One hundred and twenty-six patients (83%) were considered as PPI nonresponders and 26 (17%) as responders. No significant difference was observed for age and body mass index. No manometric and pH-impedance profiles were identified as associated with PPI response. The percentage of patients with functional dyspepsia and IBS was higher in PPI nonresponders patients than in responders (65.6% and 27.2%, respectively, vs. 38.5% and 7.7%, P = 0.01 and P = 0.03). This study confirms that functional digestive disorders are more frequent in patients with persistent GERD symptoms on PPI and they might be indicative of nonresponse to PPI therapy.

Esophageal Impedance Monitoring: Clinical Pearls and Pitfalls

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

Does the healing of the esophageal mucosa improve the function of the esophageal submucosal and salivary glands?

The esophageal pre-epithelial barrier encompasses components of secretions from both the esophageal submucosal and salivary glands. We demonstrated, in patients with reflux esophagitis (RE), significantly diminished luminal release of esophageal epidermal growth factor (EGF). The rate of luminal release of esophageal prostaglandin E₂ (PGE₂ ) was significantly higher compared with controls and significantly declined after healing of RE. Patients with RE also exhibited significant declines in esophageal mucin secretion; however, after healing of RE with rabeprazole, this rate increased significantly. The rate of salivary EGF and bicarbonate secretion in patients with RE was significantly lower than in controls. We have demonstrated that mastication of tasteless parafilm, which could be substituted with sugarless chewing gum in the clinical scenario, resulted in profound and significant increases in the rate of secretion of salivary protective factors, such as bicarbonate, mucin, protein, EGF, and PGE₂ , in patients with RE. Our data clearly indicate that there is a relationship between the form or the structure of the esophageal mucosa and the secretory function of not only the esophageal submucosal glands but also the salivary glands. Application of masticatory stimulation in a clinical scenario may also have some therapeutic potential.

Increased TRPV1 and PAR2 mRNA expression levels are associated only with the esophageal reflux symptoms, but not with the extraesophageal reflux symptoms

Transient receptor potential vanilloid-1 (TRPV1) receptor and proteinase-activated receptor 2 (PAR2) have been implicated in the mechanism of acid-induced inflammation in gastroesophageal reflux disease (GERD). We aimed to evaluate TRPV1 and PAR2 mRNA expression levels in the GERD patients and their relationship with endoscopic findings and reflux symptoms.Sixteen healthy controls, 45 patients with erosive reflux disease (ERD), and 14 nonerosive reflux disease (NERD) patients received endoscopy and completed questionnaires. Quantitative real-time polymerase chain reactions (qPCR) of TRPV1, glial cell line-derived neurotrophic factor (GDNF), nerve growth factor (NGF), PAR2, and interleukin (IL)-8 were performed in the distal esophagus specimen.The levels of TRPV1, GDNF, NGF, PAR2, and IL-8 mRNA expression were highest in the ERD group followed by NERD and control groups and the differences between control and ERD groups were statistically significant. Within the ERD group, patients with grade B in Los Angeles (LA) classification showed significantly higher levels of TRPV1, GDNF, and NGF mRNA expression than those with grade A. Presence of reflux symptoms was associated with significant higher levels of TRPV1, PAR2, and IL-8. Notably not extraesophageal but esophageal reflux symptoms were significantly associated with them.Upregulation of TRPV1 and PAR2 pathways might play a role in the development of distal esophageal inflammation and reflux symptoms. And extraesophageal reflux symptoms might not be associated with these processes.

Gastroesophageal reflux disease-related and functional heartburn: pathophysiology and treatment

PURPOSE OF REVIEW

Patients who continue to experience heartburn symptoms despite adequate-dose proton pump inhibitor therapy have unmet clinical needs. In this review, we focus on the most recent findings related to the mechanism of heartburn symptom generation, and on the treatment of gastroesophageal reflux disease-related and functional heartburn.

RECENT FINDINGS

The immunological mechanism in the esophageal mucosa has been addressed as a potential mechanism of the onset of esophageal mucosa damage and the generation of heartburn symptoms. Peripheral or central hypersensitivity in viscera is a potentially unifying pathophysiological concept in functional heartburn. Vonoprazan, a novel and potent first-in-class potassium-competitive acid blocker, is expected to prove useful in the treatment of reflux disease.

SUMMARY

New findings in the mechanisms of heartburn symptom generation are emerging, including the immunological mediation of esophageal mucosal damage and the development of visceral hypersensitivity in functional heartburn. In the future, we anticipate the emergence of new and specific therapeutic options based on these mechanisms, with less dependence on acid-suppressing agents.

Esophageal Submucosal Injection of Capsaicin but Not Acid Induces Symptoms in Normal Subjects

Background/Aims

Transient receptor potential vanilloid-1 (TRPV1) is a candidate for mediating acid-induced symptoms in the esophagus. We conducted studies to determine if the presence of acid in the mucosa/submucosa and direct activation of TRPV1 by capsaicin elicited symptoms in normal healthy subjects. We also studied the presence of TRPV1 receptors in the esophagus.

Methods

Unsedated endoscopy was performed on healthy subjects with no symptoms. Using a sclerotherapy needle, normal saline (pH 2.0–7.5) was injected into the mucosa/submucosa, 5 cm above the Z line. In a separate group of healthy subjects, injection of capsaicin and vehicle was also studied. Quality of symptoms was reported using the McGill Pain Questionnaire, and symptom intensity using the visual analogue scale (VAS). Immunohistochemistry was performed on 8 surgical esophagus specimens using TRPV1 antibody.

Results

Acid injection either did not elicit or elicited mild symptoms in subjects at all pH solutions. Capsaicin but not the vehicle elicited severe heartburn/chest pain in all subjects. Mean VAS for capsaicin was 91 ± 3 and symptoms lasted for 25 ± 1 minutes. Immunohistochemistry revealed a linear TRPV1 staining pattern between the epithelial layer and the submucosa that extended into the papillae. Eighty-five percent of papillae stained positive for TRPV1 with a mean 1.1 positive papillae per high-powered field.

Conclusions

The mechanism of acid-induced heartburn and chest pain is not the simple interaction of hydrogen ions with afferents located in the esophageal mucosa and submucosa. TRPV1 receptors are present in the lamina propria and their activation induces heartburn and chest pain.

The effects of proton pump inhibitors on autonomic tone in patients with erosive and non-erosive esophagitis

BACKGROUND

Reduction in autonomic tone as measured by heart rate variability (HRV) has been associated with various inflammatory conditions including reflux disease. The nature of and permanence of this damage have not been fully assessed.

METHODS

Fourteen individuals with non-erosive reflux disease (NERD) and 10 individuals with erosive reflux disease (ERD) as identified on endoscopy were assessed for HRV prior to starting a course of proton pump inhibitor (PPI) therapy and 8 weeks from the start of PPI therapy.

KEY RESULTS

Reflux symptoms were significantly improved by PPI therapy (p = 0.001), with no significant difference in reflux symptoms between the NERD and ERD groups either before (p = 0.45) or following therapy (p = 0.17). The ERD group displayed reduced HRV prior to PPI therapy as compared with a non-symptomatic group. There was significant improvement of HRV resulting from PPI therapy in the ERD group as measured by inspiration/expiration ratio on forced breathing (p = 0.02), Valsalva ratio (p = 0.03), and extended metronome-guided breathing at 6 breaths per minute (p = 0.03). While a similar pattern was seen in the NERD group, the effects were not as strong and did not reach statistical significance.

CONCLUSIONS & INFERENCES

The results are consistent with a growing body of evidence that cardiac autonomic neuropathy as measured by HRV is associated with gastro-esophageal reflux disease and also suggest that successful treatment of the inflammation can lead to reversal of the deterioration of autonomic tone associated with that inflammation.

A weakly acidic solution containing deoxycholic acid induces esophageal epithelial apoptosis and impairs integrity in an in vivo perfusion rabbit model

Impaired esophageal mucosal integrity may be an important contributor in the pathophysiology of gastroesophageal reflux disease (GERD). Nevertheless, the effect of potentially harmful agents on epithelial integrity is mainly evaluated in vitro for a short period of time and the possible induction of epithelial apoptosis has been neglected. Our objective was to assess the effect of an acidic and weakly acidic solution containing deoxycholic acid (DCA) on the esophageal epithelium in an in vivo rabbit model of esophageal perfusion and to evaluate the role of the epithelial apoptosis. The esophagus of 55 anesthetized rabbits was perfused for 30 min with different solutions at pH 7.2, pH 5.0, pH 1.0, and pH 5.0 containing 200 and 500 μM DCA. Thereafter, animals were euthanized immediately or at 24 or 48 h after the perfusion. Transepithelial electrical resistance, epithelial dilated intercellular spaces, and apoptosis were assessed in Ussing chambers, by transmission electron microscopy, and by TUNEL staining, respectively. No macroscopic or major microscopic alterations were observed after the esophageal perfusions. The acidic and weakly acidic solution containing DCA induced similar long-lasting functional impairment of the epithelial integrity but different ultrastructural morphological changes. Only the solution containing DCA induced epithelial apoptosis in vivo and in vitro in rabbit and human tissue. In contrast to acid, a weakly acidic solution containing DCA induces epithelial apoptosis and a long-lasting impaired mucosal integrity. The presence of apoptotic cells in the esophageal epithelium may be used as a marker of impaired integrity and/or bile reflux exposure.

Effects of esophageal capsaicin instillation on acid induced excitation of secondary peristalsis in humans

BACKGROUND/AIM

Esophageal instillation of capsaicin or hydrochloric acid enhances secondary peristalsis. Our aim was to investigate whether intra-esophageal capsaicin infusion can influence symptom perception and physiological alteration of secondary peristalsis subsequent to acid infusion.

METHODS

Secondary peristalsis was induced by mid-esophagus injections of air in 18 healthy subjects. Two different sessions including esophageal infusion of hydrochloric acid (0.1 N) following pretreatment with saline or capsaicin-containing red pepper sauce were randomly performed at least one week apart. Symptoms of heartburn and secondary peristalsis were determined and compared between each study session.

RESULTS

The intensity of heartburn symptom subsequent to acid infusion was significantly reduced after capsaicin infusion as compared with saline infusion (54 ± 3 vs 61 ± 3; P = 0.03). Capsaicin infusion significantly increased the threshold volume of secondary peristalsis to rapid air injections subsequent to esophageal acid infusion (8.0 ± 0.5 mL vs 4.4 ± 0.3 mL; P < 0.0001). The frequency of secondary peristalsis subsequent to acid infusion was significantly decreased after capsaicin infusion as compared to saline infusion (70% [60-82.5%] vs 80% [70-90%]; P = 0.03). Capsaicin infusion significantly decreased the pressure wave amplitude of secondary peristalsis subsequent to acid infusion during rapid air injections (90.6 ± 8.7 mmHg vs 111.1 ± 11.1 mmHg; P = 0.03).

CONCLUSIONS

Capsaicin appears to desensitize the esophagus to acid induced excitation of secondary peristalsis in humans, which is probably mediated by rapidly adapting mucosal mechanoreceptors. High capsaicin-containing diet might attenuate normal physiological response to abrupt acid reflux by inhibiting secondary peristalsis.

Altered Esophageal Mucosal Structure in Patients with Celiac Disease

Background/Aim. Reflux symptoms (RS) are common in patients with celiac disease (CD), a chronic enteropathy that affects primarily the small intestine. We evaluated mucosal integrity and motility of the lower esophagus as mechanisms contributing to RS generation in patients with CD. Methods. We enrolled newly diagnosed CD patients with and without RS, nonceliac patients with classical reflux disease (GERD), and controls (without RS). Endoscopic biopsies from the distal esophagus were assessed for dilated intercellular space (DIS) by light microscopy and electron microscopy. Tight junction (TJ) mRNA proteins expression for zonula occludens-1 (ZO-1) and claudin-2 and claudin-3 (CLDN-2; CLDN-3) was determined using qRT-PCR. Results. DIS scores were higher in patients with active CD than in controls, but similar to GERD patients. The altered DIS was found even in CD patients without RS and normalized after one year of a gluten-free diet. CD patients with and without RS had lower expression of ZO-1 than controls. The expression of CLDN-2 and CLDN-3 was similar in CD and GERD patients. Conclusions. Our study shows that patients with active CD have altered esophageal mucosal integrity, independently of the presence of RS. The altered expression of ZO-1 may underlie loss of TJ integrity in the esophageal mucosa and may contribute to RS generation.

Patients with refractory reflux symptoms often do not have GERD

BACKGROUND

In patients with typical reflux symptoms that persist despite proton pump inhibitors (PPIs) it is sometimes overlooked that treatment fails due to the presence of other disorders than gastroesophageal reflux disease (GERD). The aim of this study was to determine the underlying cause of reflux symptoms not responding to PPI therapy in tertiary referral patients.

METHODS

Patients with reflux symptoms refractory to PPI therapy who underwent 24-h pH-impedance monitoring were analyzed. Patients in whom a diagnosis was already established before referral, who had previous esophageal or gastric surgery, or who had abnormalities on gastroscopy other than hiatus hernia, were excluded.

KEY RESULTS

In total, 106 patients were included. Esophageal manometry showed achalasia in two patients and distal esophageal spasm in another two. Twenty-four-hour pH-impedance monitoring revealed a total acid exposure time <6% in 60 patients (56.6%) of which 25 had a positive symptom association probability (SAP) while 35 showed a negative SAP. Sixty-nine patients ended up with a final diagnosis of GERD while 32 patients (30.2%) were diagnosed with functional heartburn (FH), two with functional chest pain, two with achalasia, and one with rumination. A trend toward an association with a final diagnosis of FH was found with the atypical symptom epigastric pain (p = 0.059) and with a secondary diagnosis of functional dyspepsia (p = 0.083).

CONCLUSIONS & INFERENCES

Approximately one-third of the patients referred with refractory reflux symptoms suffer from disorders other than GERD, predominantly FH. This explains, at least partly, why many patients will not benefit from acid inhibitory treatment.

Evidence for neuronal and structural changes in submucous ganglia of patients with functional dyspepsia

OBJECTIVES

An intact and well-functioning enteric nervous system is necessary to efficiently organize gut function. Functional gastrointestinal disorders are pathological entities in which gut function is impaired without a clearly established pathophysiology. On the basis of the relative ease with which intestinal biopsies can be obtained, and taking advantage of a recently developed optical recording technique, we evaluated whether functional neuronal defects exist in enteric nerves of patients with functional dyspepsia (FD).

METHODS

The submucous plexus isolated from duodenal biopsies taken from FD patients and control subjects was used to functionally and morphologically examine nerves and ganglionic architecture (neurons and glial cells). In light of previous studies reporting eosinophil and mast cell infiltration in the gut mucosa of FD patients, we also examined whether these cells infiltrated the submucous plexus and whether this correlated with neuronal activity and specific clinical symptoms.

RESULTS

We demonstrate that neuronal functioning is impaired in the submucous plexus of FD patients, as shown by decreased calcium responses to depolarization and electrical stimulation. Glial (S100) and neuronal (HuCD) markers show signs of gliosis, altered ganglionic architecture, and neuronal abnormalities in the submucous plexus of FD patients. We found that eosinophils and mast cells infiltrated the submucous layer of FD patients to a much larger extent than in controls. A significant correlation was found between the number of these cells and the calcium transient amplitudes measured in submucous ganglia.

CONCLUSIONS

We provide the first direct evidence that FD is characterized by functional and structural abnormalities within the submucous ganglion plexus, which may be of future predictive and diagnostic value in the treatment of FD patients.

Correlation between hypersensitivity induced by esophageal acid infusion and the baseline impedance level in patients with suspected gastroesophageal reflux

OBJECTIVES

To evaluate the relevance between the pH parameters and baseline impedance level or esophageal hypomotility in patients with suspected gastroesophageal reflux.

METHOD

The recordings of 51 patients with heartburn, acid regurgitation, globus or noncardiac chest pain were analyzed. Evaluation included a 24-h multichannel intraluminal impedance-pH test while on off-proton pump inhibitor therapy over 1 week, high-resolution manometry and Bernstein test. Mean baseline impedance level at the most distal portion of the impedance channel was assessed manually. Esophageal hypomotility was evaluated using transitional zone defect (TZD) and distal break (DB) length measurement.

RESULT

In the study subjects (n = 51), 6 had a DeMeester score of more than 14.7 and 14 had a positive symptom index. The Bernstein test was positive in ten patients. The baseline impedance level was inversely correlated with the acid exposure time % (r = -0.660, P < 0.001). Also, all reflux and weakly acid reflux time % measured by impedance monitoring showed a weak correlation with TZD + DB length (r = 0.327 and 0.324, P = 0.019 and 0.020, respectively). Although a positive Bernstein test has no relevance for the acid exposure time or acid-related symptoms as represented by the DeMeester score or symptom index, the baseline impedance level was significantly lower in patients with a positive Bernstein test than in those with a negative one (2,628.4 ± 862.7 vs. 1,752.2 ± 611.1 Ω, P = 0.004).

CONCLUSION

A lower baseline impedance level is closely related to increased esophageal acid exposure. Hypersensitivity induced by esophageal acid infusion might be attributed to acid-induced mucosal changes of the esophagus.

A Meta-Analysis of Randomized Controlled Trials to Compare Long-Term Outcomes of Nissen and Toupet Fundoplication for Gastroesophageal Reflux Disease

Aim

In recent years, several studies with large sample sizes and recent follow-up data have been published comparing outcomes between laparoscopic Nissen fundoplication and laparoscopic Toupet fundoplication. It is now timely to be re-evaluated and synthesized long-term efficacy and adverse events of both total and partial posterior fundoplication.

Materials and Methods

Electronic searches for RCTs comparing the outcome after laparoscopic Nissen fundoplication and laparoscopic Toupet fundoplication were performed in the databases of MEDLINE, EMBASE, and the Cochrane Center Register of Controlled Trials. The data of evaluation in positive and adverse results of laparoscopic Nissen fundoplication and laparoscopic Nissen fundoplication were extracted and compared using meta-analysis.

Results

13 RCTs were ultimately identified involving 814 (52.05%) and 750 (47.95%) patients who underwent laparoscopic Nissen fundoplication and laparoscopic Toupet fundoplication, respectively. The operative time, perioperative complications, postoperative satisfaction, recurrence, and the rates of medication adoption or re-operation due to recurrence were not significantly different between two groups. The two types of fundoplication both reinforced the anti-reflux barrier and elevated the lower esophageal sphincter pressure. However, rates of adverse results involving dysphasia, gas-bloat syndrome, inability to belch and re-operation due to severe dysphasia were significantly higher after LNF. In the subgroup analysis of wrap length≤2cm, laparoscopic Nissen fundoplication was associated with a significantly higher incidence of postoperative dysphagia. However, in the subgroup wrap length>2cm, the difference was not statistically significant.

Conclusion

Laparoscopic Toupet fundoplication might be the better surgery approach for gastroesophageal reflux disease with a lower rate of postoperative adverse results and equal effectiveness as Laparoscopic Nissen fundoplication.

The effect of endoscopic fundoplication and proton pump inhibitors on baseline impedance and heartburn severity in GERD patients

BACKGROUND

Antireflux therapy may lead to recovery of impaired mucosal integrity in gastro-esophageal reflux disease (GERD) patients as reflected by an increase in baseline impedance. The study objective was to evaluate the effect of endoscopic fundoplication and proton pump inhibitor (PPI) PPI therapy on baseline impedance and heartburn severity in GERD patients.

METHODS

Forty-seven GERD patients randomized to endoscopic fundoplication (n = 32) or PPI therapy (n = 15), and 29 healthy controls were included. Before randomization and 6 months after treatment, baseline impedance was obtained during 24-h pH-impedance monitoring. Heartburn severity was evaluated using the GERD-HRQL questionnaire.

KEY RESULTS

Before treatment, baseline impedance in GERD patients was lower than in healthy controls (p < 0.001). Antireflux therapy increased baseline impedance (from 1498 [IQR 951-2472] to 2393 [IQR 1353-3027] Ω, p = 0.001), however it only led to a partial recovery when compared to healthy controls (2393 [IQR 1353-3027] vs 2983 [2335-3810] Ω, p < 0.01). The effect of both treatment options was not significantly different (p = 0.13) despite the increased number of non-acid reflux events in the PPI group. No correlation was found between baseline impedance and GERD symptoms before or after treatment.

CONCLUSIONS & INFERENCES

Reduction in acid reflux by endoscopic fundoplication or PPI therapy leads to an increase in baseline impedance in GERD patients, likely to reflect recovery of mucosal integrity. The impact of non-acid reflux events on esophageal mucosal integrity may be limited as no difference in the increase in baseline impedance was observed after both treatment options. The lack of association between impedance baseline and heartburn severity indicates that other factors may contribute to heartburn perception in GERD.

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.

Hypersensitivity to acid is associated with impaired esophageal mucosal integrity in patients with gastroesophageal reflux disease with and without esophagitis

Increased esophageal sensitivity and impaired mucosal integrity have both been described in patients with gastroesophageal reflux disease, but the relationship between hypersensitivity and mucosal integrity is unclear. The aim of the present study was to investigate acid sensitivity in patients with erosive and nonerosive reflux disease and control subjects to determine the relation with functional esophageal mucosal integrity changes as well as to investigate cellular mechanisms of impaired mucosal integrity in these patients. In this prospective experimental study, 12 patients with nonerosive reflux disease, 12 patients with esophagitis grade A or B, and 11 healthy control subjects underwent an acid perfusion test and upper endoscopy. Mucosal integrity was measured during endoscopy by electrical tissue impedance spectroscopy and biopsy specimens were analyzed in Ussing chambers for transepithelial electrical resistance, transepithelial permeability and gene expression of tight junction proteins and filaggrin. Patients with nonerosive reflux disease and esophagitis were more sensitive to acid perfusion compared with control subjects, having a shorter time to perception of heartburn and higher perceived intensity of heartburn. In reflux patients, enhanced acid sensitivity was associated with impairment of in vivo and vitro esophageal mucosal integrity. Mucosal integrity was significantly impaired in patients with esophagitis, displaying higher transepithelial permeability and lower extracellular impedance. Although no significant differences in the expression of tight junction proteins were found in biopsies among patient groups, mucosal integrity parameters in reflux patients correlated negatively with the expression of filaggrin. In conclusion, sensitivity to acid is enhanced in patients with gastroesophageal reflux disease, irrespective of the presence of erosions, and is associated with impaired esophageal mucosal integrity. Mucosal integrity of the esophagus is associated with the expression of filaggrin.

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.

Involvement of luminal nitric oxide in the pathogenesis of the gastroesophageal reflux disease spectrum

Over the last 3 decades, the incidence of esophageal adenocarcinoma has dramatically increased in Western countries; a similar increase may be observed in Asian countries in the near future. Esophageal adenocarcinoma arises from a sequential gastroesophageal reflux disease (GERD) spectrum from reflux erosive esophagitis, to Barrett's esophagus, and finally to esophageal adenocarcinoma. At present, gastric acid and bile are assumed to be primarily involved in the etiology of the GERD spectrum. We reported in 2002 that, at the gastroesophageal junction in humans, abundant amounts of nitric oxide (NO) are generated luminally through the entero-salivary re-circulation of dietary nitrate. Since then, we have carried out a series of experiments to demonstrate that NO diffuses into the adjacent epithelium at cytotoxic levels. This diffusion results in disruption of the epithelial barrier function, exacerbation of inflammation, acceleration of columnar transformation in the esophagus (Barrett's esophagus) via the induction of caudal-type homeobox 2, and the shifting of carcinogenic N-nitroso compound formation from the luminal to epithelial compartment. These results suggest that, in addition to conventionally recognized causative factors, luminal NO could also be involved in the pathogenesis of the GERD spectrum. In addition, we recently showed that there is a prominent gender-related difference in NO-related cytotoxicity in the esophagus and that estrogen attenuated the esophageal tissue damage via the estrogen receptor in female rats. The role of estrogen in attenuating the esophageal tissue damage in NO-related esophageal damage could explain the well-recognized male predominance in the GERD spectrum in humans.

Medical treatments of GERD: the old and new

The mainstay of pharmacological therapy for GERD is gastric acid suppression with proton pump inhibitors (PPIs), which are superior to histamine-2 receptor antagonists for healing erosive esophagitis and achieving symptomatic relief. However, up to one-third of patients may not respond to PPI therapy, creating the need for alternative treatments. Potential approaches include transient lower esophageal sphincter relaxation inhibitors, augmentation esophageal defense mechanisms by improving esophageal clearance or enhancing epithelial repair, and modulation of sensory pathways responsible for GERD symptoms. This review discusses the effectiveness of acid suppression and the data on alternative pharmacological approaches for the treatment of GERD.

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.

Intraluminal acid activates esophageal nodose C fibers after mast cell activation

Acid reflux in the esophagus can induce esophageal painful sensations such as heartburn and noncardiac chest pain. The mechanisms underlying acid-induced esophageal nociception are not clearly understood. In our previous studies, we characterized esophageal vagal nociceptive afferents and defined their responses to noxious mechanical and chemical stimulation. In the present study, we aim to determine their responses to intraluminal acid infusion. Extracellular single-unit recordings were performed in nodose ganglion neurons with intact nerve endings in the esophagus using ex vivo esophageal-vagal preparations. Action potentials evoked by esophageal intraluminal acid perfusion were compared in naive and ovalbumin (OVA)-challenged animals, followed by measurements of transepithelial electrical resistance (TEER) and the expression of tight junction proteins (zona occludens-1 and occludin). In naive guinea pigs, intraluminal infusion with either acid (pH = 2-3) or capsaicin did not evoke an action potential discharge in esophageal nodose C fibers. In OVA-sensitized animals, following esophageal mast cell activation by in vivo OVA inhalation, intraluminal acid infusion for about 20 min started to evoke action potential discharges. This effect is further confirmed by selective mast cell activation using in vitro tissue OVA challenge in esophageal-vagal preparations. OVA inhalation leads to decreased TEER and zona occludens-1 expression, suggesting an impaired esophageal epithelial barrier function after mast cell activation. These data for the first time provide direct evidence of intraluminal acid-induced activation of esophageal nociceptive C fibers and suggest that mast cell activation may make esophageal epithelium more permeable to acid, which subsequently may increase esophageal vagal nociceptive C fiber activation.

Esophageal mucosal integrity in nonerosive reflux disease

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

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.

Gastrointestinal sensitivity and gastroesophageal reflux disease

This paper reports on gastrointestinal sensitivity, including on the role of refluxate volume on the perception of reflux symptoms; experimental pain models that mimic mechanisms and symptoms of pain associated with esophageal diseases; the potential role of the acid receptor TRPV1 in the genesis of gastroesophageal reflux disease (GERD) symptoms; and roles for ATP and the purine and pyrimidine receptor subfamilies P1, P2X, and P2Y in the pathogenesis of GERD symptoms.

Eosinophilic esophagitis in adults: an update on medical management

Management of eosinophilic esophagitis (EoE) centers around the 3 Ds: diet, drug therapy, and dilation. Unfortunately, there is not a consistent relationship between symptom relief and resolution of mucosal eosinophilia. Elemental diets are very successful in children, but poorly tolerated by adults. The 6-food elimination diet is more attractive to adults, especially for those individuals with multiple food allergies. Steroids are the preferred anti-eosinophil drug for EoE. Oral prednisone is infrequently used because of side effects. Topical swallowed preparations (fluticasone, budesonide) are preferred for acute and possibly maintenance therapy. Relapses off steroids are frequent and dysphagia does not predictably improve. Esophageal dilation is key treatment for patients with the fibrostenotic phenotype of EoE. Long-term symptom relief for 1-2 years is common. Post-procedure chest pain is to be expected but perforation is very rare. A suggested algorithm for the treatment of EoE based on endoscopic phenotypes is outlined.

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.

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

BACKGROUND

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

PURPOSE

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

Esophageal barrier function and tight junction expression in healthy subjects and patients with gastroesophageal reflux disease: functionality of esophageal mucosa exposed to bile salt and trypsin in vitro

BACKGROUND AND AIMS. Gastroesophageal reflux disease (GERD) is associated with impaired epithelial barrier function. However, the influence of acid and/or bile acids on human esophageal epithelial barrier function and the tight junction (TJ) proteins has not been fully elucidated. The aim of the study is to investigate the esophageal barrier function and TJ expression in healthy subjects and patients with GERD. The functionality of esophageal mucosa exposed to bile salt deoxycholic acid (DCA) and trypsin has been studied in vitro. MATERIAL AND METHODS. Endoscopic biopsies from healthy controls and patients with GERD-related symptom with endoscopic erosive signs, as well as esophageal mucosa taken from patients undergoing esophagectomy were evaluated in Ussing chambers and by western blot and immunohistochemistry. RESULTS. The esophageal epithelium from GERD patients had lower electrical resistance and higher epithelial currents than controls. Claudin-1 and -4 were significantly decreased in GERD patients. The bile salt DCA in the low concentration of 1.5 mM and trypsin increased the resistance and claudin-1 expression, while the higher concentration of 2.5 mM DCA and trypsin decreased the resistance and the claudin-3, -4 and E-cadherin expressions. CONCLUSION. In addition to acidic reflux, duodenal reflux components, such as bile salts and trypsin, have the potential to disrupt the esophageal barrier function, partly by modulating the TJ proteins. However, the expression of TJ is dependent on both the refluxed material as well as the concentration of the bile salt.

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

OBJECTIVE

Patients with non-erosive reflux disease (NERD) have impaired oesophageal mucosal integrity (dilated intercellular spaces). Oesophageal mucosal integrity reflects the balance between repeated reflux damage and mucosal recovery. The relationship between mucosal integrity and acid sensitivity is unclear. Oesophageal impedance may be used for in vivo mucosal integrity measurement. We studied acid-induced changes in oesophageal mucosal integrity and acid perception in patients with heartburn.

DESIGN

50 patients with heartburn whithout oesophagitis underwent impedance monitoring before, during and after 10 min oesophageal perfusion with neutral (pH 6.5) and acid solutions (pH 1). Symptoms and impedance were recorded during perfusion. Impedance recovery was assessed for 2 h post-perfusion in ambulatory conditions followed by 24-h impedance-pH study.

RESULTS

Reflux monitoring discriminated 20 NERD and 30 functional heartburn (FH) patients. Neutral perfusion caused impedance fall that recovered within 10 min. Acid perfusion caused impedance fall with slow recovery: 6.5 Ω/min (IQR 3.3-12.0 Ω/min). Patients with slow recovery (< 25th percentile) had lower baseline impedance (1273 Ω ± 208 Ω vs. 3220 Ω ± 275 Ω ±, p < 0.01) and more frequent acid sensitivity (10/12 vs. 4/12, p = 0.04) than those with fast (> 75th percentile) recovery. Patients with NERD had lower baseline impedance (1669 ± 182 Ω vs. 2384 ± 211 Ω, p = 0.02) and slower impedance recovery (6.0 ± 0.9 Ω/min vs. 10.7 ± 1.6 Ω/min, p = 0.03) than patients with FH.

CONCLUSION

Impaired mucosal integrity might be the consequence of repeated reflux episodes with slow recovery. Mucosal integrity, recovery capacity and symptom perception are linked. Low basal impedance and slow recovery after acid challenge are associated with increased acid sensitivity.

The relationship between complaints of night-time heartburn and sleep-related gastroesophageal reflux

This study investigated whether the complaint of night-time heartburn (NHB) as opposed to daytime heartburn (DHB) is a reliable reflection of actual sleep-related reflux events. Three groups of individuals were studied: individuals with complaints of NHB at least twice per week (n = 24), individuals with complaints of DHB (n = 23), and normal participants without any complaints of regular heartburn during the day or night (n = 25). All three groups were studied on one occasion with combined pH monitoring and polysomnography, and subjective questionnaires about sleep disturbance and sleep quality were given to all participants. The NHB group had significantly more sleep-related reflux events compared with both DHB and control groups (P < 0.01). DHB subjects had significantly (P < 0.05) more sleep-related reflux events than normal controls. Total acid contact time (ACT) was significantly (P < 0.05) elevated in the NHB group compared with both the DHB and control group. Sleep-related ACT was also significantly (P < 0.05) elevated in the NHB group compared with the other two groups, while upright (daytime) ACT was not significantly different. The NHB group was significantly (P < 0.05) worse regarding measures of both objective and subjective sleep quality. Subjects with exclusively DHB do have sleep-related reflux that is greater than normal controls. Subjects with NHB have significantly more sleep-related reflux, and both objective and subjective sleep abnormalities compared with normal controls. Complaints of NHB reflect sleep-related reflux events and may be indicative of a more clinically significant condition.

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.

Association of sleep dysfunction and emotional status with gastroesophageal reflux disease in Korea

BACKGROUND/AIMS

Sleep disturbances and emotional dysfunction are commonly associated with gastroeophageal reflux disease (GERD). The aims of this study were to evaluate GERD symptoms and disturbance in erosive reflux disease (ERD) and nonerosive reflux disease (NERD) patients, and to compare sleep dysfunction, depressive mood, anxiety and quality of life (QOL) among the control, ERD and NERD patients in Korea.

METHODS

The Korean subjects were enrolled between 2010 and 2012, classified into 3 groups; the control group with no symptom and normal endoscopic findings, the ERD group with erosive esophagitis and the NERD group with more than one episode of heartburn or acid regurgitation per week, positive response to proton pump inhibitor, and normal endoscopic findings. Questionnaire included GERD symptoms, GERD impact scale (GIS) and daytime pathological sleepiness (Epworth sleepiness scale), sleep dysfunction (Pittsburgh sleep quality index, PSQI), depression and anxiety (Hospital anxiety and depression scale, HADS) and QOL (WHO quality of life scale abbreviated version, WHOQOL-BREF).

RESULTS

A total of 217 subjects were enrolled as follows; control (n = 70), ERD (n = 70) and NERD (n = 77). Impact of symptom of GIS score was higher in the NERD (9.2 ± 0.4) than in the ERD (6.5 ± 0.3) group (P < 0.001). Sleep dysfunctions were more frequent in GERD than the control group (PSQI score [P = 0.021]). Anxiety subscale of HAD score was higher in NERD (7.0 ± 0.5, P = 0.002) and ERD (6.2 ± 0.7, P = 0.004) groups than control (4.3 ± 0.7) group. WHOQOL-BREF scores in NERD (54.9 ± 2.3) and ERD (57.8 ± 2.4) groups were significantly lower than those in the control group (63.8 ± 2.4) (P = 0.002; P = 0.014, respectively).

CONCLUSIONS

The patients with NERD than ERD suffered more from the symptoms and disturbance in Korea. Sleep dysfunction and anxiety mood were higher and QOL was decreased in GERD, especially in NERD, suggesting that those factors might affect the severity of NERD.

Effect of amiloride on experimental acid-induced heartburn in non-erosive reflux disease

BACKGROUND

Acid-sensing ion channels (ASICs) are esophageal nociceptors that are candidates to mediate heartburn in non-erosive reflux disease (NERD). Amiloride, a diuretic, is known to inhibit ASICs. For this reason, we sought a role for ASICs in mediating heartburn by determining whether amiloride could block heartburn in NERD induced by esophageal acid perfusion.

METHODS

In a randomized double-blind crossover study, we perfused the esophagus with amiloride or (saline) placebo prior to eliciting acid-induced heartburn in patients with a history of proton pump inhibitor-responsive NERD. Those with NERD and positive modified Bernstein test were randomized to perfusion with amiloride, 1 mmol/l, or placebo for 5 min, followed by repeat acid-perfusion. Heartburn severity and time to onset was measured and the process repeated following crossover to the alternative agent.

RESULTS

14 subjects completed the study. Amiloride did not reduce the frequency (100 vs. 100 %) or severity of acid-induced heartburn (Mean 2.50 ± SEM 0.33 vs. 2.64 ± 0.45), respectively. There was a trend towards longer time to onset of heartburn for amiloride versus placebo (Mean 2.93 ± SEM 0.3 vs. 2.36 ± 0.29 min, respectively), though these differences did not reach statistical significance (p > 0.05).

CONCLUSIONS

Amiloride had no significant effect on acid-induced heartburn frequency or severity in NERD, although there was a trend towards prolonged time to onset of symptoms.

Electrical tissue impedance spectroscopy: a novel device to measure esophageal mucosal integrity changes during endoscopy

BACKGROUND

Patients with gastroesophageal reflux disease (GERD) have impaired esophageal mucosal integrity. Measurement of the mucosal integrity is complex and time-consuming. Electrical tissue impedance spectroscopy (ETIS) is a device that measures impedance of tissue in vivo during endoscopy. In this study, we aimed to validate ETIS as a measure of esophageal mucosal integrity.

METHODS

Electrical tissue impedance spectroscopy measurements were performed during upper endoscopy in 12 GERD patients and 11 healthy controls after cessation of proton pump inhibition. During endoscopy biopsies of the distal esophagus were obtained for transmission electron microscopy to determine dilation of intercellular spaces (DIS) and for Ussing chamber experiments to determine transepithelial permeability and transepithelial electrical resistance.

KEY RESULTS

Extracellular impedance measured in vivo by ETIS was significantly lower in GERD patients compared to controls [mean (SD) 5621 (3299) Ω.m and 8834 (2542) Ω.m, respectively, P < 0.05]. We found a strong inverse relation between extracellular impedance determined by ETIS and DIS (r = -0.76, P < 0.05), and between extracellular resistance in vivo and transepithelial permeability of esophageal biopsies (r = -0.65, P < 0.01).

CONCLUSIONS & INFERENCES

Electrical tissue impedance spectroscopy is a new tool that can be used to evaluate esophageal mucosal integrity changes during endoscopy.

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.

Novel therapeutics for gastro-esophageal reflux symptoms

Approximately 20-30% of patients with gastro-esophageal reflux symptoms report inadequate symptom relief while on proton-pump inhibitor therapy. The mechanisms involved are failure of the antireflux barrier (transient lower esophageal sphincter relaxations), high proximal extent of the refluxate, esophageal hypersensitivity and impaired mucosal integrity. Persisting acid or nonacid reflux can be demonstrated in 40-50% of cases, suggesting that there is room for antireflux therapy in these patients. New antireflux compounds have been shown to decrease the occurrence of transient lower esophageal sphincter relaxations. The most promising classes of compounds are GABA type B agonists and metabotropic glutamate receptor 5 antagonists, which can reduce both reflux episodes and symptoms, but the development of these compounds has been abandoned for either safety issues or lack of efficacy. Esophageal hypersensitivity and impaired mucosal integrity may prove to be relevant therapeutic targets in the future.

Association between metabolic syndrome and prevalence of gastroesophageal reflux disease in a health screening facility in Japan

BACKGROUND

Abdominal fat accumulation, which induces high intra-abdominal pressure that causes increase in the gastroesophageal pressure gradient and hiatal hernia, as well as obesity, has been shown to increase the prevalence of gastroesophageal reflux disease (GERD). This study was performed to clarify the association between metabolic syndrome and the prevalence of GERD.

METHODS

The study subjects were an adult population who visited a medical center for annual medical check-ups from April 2010 to March 2011. GERD was diagnosed by the presence of endoscopically proven reflux esophagitis, GERD symptoms (QUEST score ≥6), or current medical therapy for GERD. The presence of metabolic or pre-metabolic syndrome was diagnosed based on the Japanese criteria for metabolic syndrome.

RESULTS

Six hundred four (16.0 %) of 3775 study subjects were positively diagnosed with GERD, with the number of those with metabolic and pre-metabolic syndrome being 477 (12.6 %) and 384 (10.2 %), respectively. Multiple logistic regression analysis showed that male gender, presence of hiatal hernia, and metabolic or pre-metabolic syndrome, as well as absence of gastric mucosal atrophy, were significant predictive factors for the prevalence of GERD, as were visceral fat accumulation and untreated dyslipidemia. Untreated hypertension and untreated hyperglycemia were also considered to be positive risk factors. Subjects undergoing treatment for hypertension showed an increased risk of GERD, while those undergoing treatment for dyslipidemia and diabetes mellitus showed a decreased risk.

CONCLUSION

Metabolic syndrome is a reliable predictive factor for the prevalence of GERD, and medical therapy for metabolic syndrome may modify the risk of GERD occurrence.

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

OBJECTIVES

Intact esophageal mucosal integrity is essential to prevent symptoms during gastroesophageal reflux events. Approximately 70% of patients with heartburn have macroscopically normal esophageal mucosa. In patients with heartburn, persistent functional impairment of esophageal mucosal barrier integrity may underlie remaining symptoms. Topical protection of a functionally vulnerable mucosa may be an attractive therapeutic strategy. We aimed to evaluate esophageal mucosal functional integrity in patients with heartburn without esophagitis, and test the feasibility of an alginate-based topical mucosal protection.

METHODS

Three distal esophageal biopsies were obtained from 22 patients with heartburn symptoms, and 22 control subjects. In mini-Ussing chambers, the change in transepithelial electrical resistance (TER) of biopsies when exposed to neutral, weakly acidic, and acidic solutions was measured. The experiment was repeated in a further 10 patients after pretreatment of biopsies with sodium alginate, viscous control, or liquid control "protectant" solutions.

RESULTS

Biopsy exposure to neutral solution caused no change in TER. Exposure to weakly acidic and acidic solutions caused a greater reduction in TER in patients than in controls (weakly acid -7.2% (95% confidence interval (CI) -9.9 to -4.5) vs. 3.2% (-2.2 to 8.6), P<0.05; acidic -22.8% (-31.4 to 14.1) vs. -9.4% (-17.2 to -1.6), P<0.01). Topical pretreatment with alginate but not with control solutions prevented the acid-induced decrease in TER (-1% (-5.9 to 3.9) vs. -13.5 (-24.1 to -3.0) vs. -13.2 (-21.7 to -4.8), P<0.05).

CONCLUSIONS

Esophageal mucosa in patients with heartburn without esophagitis shows distinct vulnerability to acid and weakly acidic exposures. Experiments in vitro suggest that such vulnerable mucosa may be protected by application of an alginate-containing topical solution.

Functional heartburn: clinical characteristics and outcome

OBJECTIVES

Patients with heartburn and normal upper gastrointestinal endoscopy, normal oesophageal acid exposure, no symptom-reflux association and who fail to respond to a proton-pump inhibitor are classified as having functional heartburn (FH). This study aimed (i) to characterize the symptoms and functional abnormalities of patients with FH and (ii) to describe their clinical outcome.

MATERIALS AND METHODS

Among all patients referred for 24 h multichannel intraluminal impedance-pH (MII-pH), patients with FH were identified. The clinical characteristics and high-resolution oesophageal pressure topography recordings of FH patients were analyzed at the time of the 24-h MII-pH test. A symptom-related and health-related quality-of-life questionnaire was then sent to FH patients to assess the long-term outcome.

RESULTS

Forty patients fulfilled the criteria for FH, representing 8.5% of the referred population. Twenty-two months after initial testing, 66% of patients still suffered from heartburn. The rate of mixed reflux (liquid/gas) was higher in patients with persisting heartburn at the final evaluation (63 vs. 50%, P=0.04). Sixty-six per cent of patients had one or more manometric abnormalities. Acid clearance time in MII-pH was significantly higher in patients with weak peristalsis than patients with normal peristalsis (60 ± 45 vs. 31 ± 19 s, P=0.03). A high rate of mixed reflux and/or a manometric abnormality were associated with a higher risk of persistent heartburn.

CONCLUSION

FH is a chronic disorder with persisting symptoms in two-thirds of patients. An increased rate of mixed reflux and/or the presence of manometric abnormalities are associated with a higher risk of persisting symptoms and may help to identify the population with unmet therapeutic needs.