Intra-oesophageal distribution and perception of acid reflux in patients with non-erosive gastro-oesophageal reflux disease

Measurement of acid exposure of proximal esophagus: a better tool for diagnosing non-erosive reflux disease

BACKGROUND

The sensitivity of 24-h pH monitoring is poor in non-erosive reflux disease (NERD). In NERD patients, the proximal extent of acid reflux is one of the main determinants of reflux perception. The present study was aimed to compare the diagnostic accuracy of acid exposure time (AET), at 5 cm above the lower esophageal sphincter, with those at 10 cm and at 3 cm below the upper esophageal sphincter as well as the reproducibility of these parameters.

METHODS

A total of 93 consecutive NERD patients, with typical symptoms responsive to proton pump inhibitor treatment, and 40 controls underwent esophageal manometry and multi-channel 24-h pH-test; 13 patients underwent the same study on two occasions. Symptom association probability (SAP) values were evaluated at each esophageal level.

KEY RESULTS

The ROC curve indicates that the area under the curve was 0.79 at distal (SE=0.039), 0.87 (SE=0.032) at proximal (P=0.029 vs distal), and 0.85 (SE=0.033) at very proximal esophagus (P =0.148). AET showed a reproducibility of 61% (Kappa 0.22) at distal esophagus, 77% (Kappa 0.45) at proximal and 53% (Kappa 0.05) at very proximal esophagus. The percentage of patients with a positive SAP was not significantly different when assessed at the distal compared with the proximal esophagus.

CONCLUSIONS & INFERENCES

In NERD patients, the diagnostic yield of the pH test is significantly improved by the assessment of AET at the proximal esophagus. As this variable seems to be less affected by the day to day variability, it could be considered a reliable and useful diagnostic tool in NERD patients.

Cardiovascular compression of the esophagus and spread of gastro-esophageal reflux

BACKGROUND

Factors that determine the spread of gastro-esophageal reflux (GER) along the length of the esophagus are not known. We investigated if cardiovascular (CV) compressions on the esophagus may determine the spread of refluxate into the proximal esophagus.

METHODS

High-resolution manometry (HRM) and multi-channel intra-luminal impedance recording (MIIR) were performed simultaneously in 10 normal subjects in the recumbent and upright positions. Pulsatile pressure increases on the esophagus (marker of CV compression) were identified on the HRM. Spread of refluxate into the esophagus was determined by the MIIR.

KEY RESULTS

Cardiovascular compression zones were observed in the esophagus in 9 out of 10 subjects in recumbent position. Forty percent of GER episodes were limited to the distal esophagus in the recumbent position and CV compression pressure was greater than distal esophageal pressure at the time of GER in all such cases. On the other hand, distal esophageal pressure was greater than CV compression pressure when the refluxate extended into the proximal esophagus. In the upright position, CV compression was less frequent than recumbent position and only 12% of GER episodes were limited to the distal esophagus.

CONCLUSIONS & INFERENCES

Cardiovascular compression of the esophagus is frequently observed in normal healthy subject and restricts the spread of refluxate into the proximal esophagus.

Medical treatment of GORD. Emerging therapeutic targets and concepts

Approximately 20-30% of patients with gastro-oesophageal reflux symptoms report inadequate symptom relief while on PPI therapy. Persisting acid or non-acid reflux can be demonstrated in 40-50% of them suggesting that there is room for anti-reflux therapy in these patients. New anti-reflux compounds aim at decreasing the occurrence of transient lower oesophageal sphincter relaxations (TLOSRs) which represent the main mechanism of all types of reflux. The most promising classes of compounds are GABA(B) agonists and mGluR5 antagonists which have been shown to reduce both reflux episodes and symptoms and are currently under evaluation in phase II and III clinical trials. Compounds that target TLOSR activity represent a promising new therapeutic option for patients who suffer from GORD symptoms. These drugs will probably be developed as add-on therapy in combination with PPIs provided the tolerability and safety issues are resolved.

The refluxate: The impact of its magnitude, composition and distribution

The pathogenesis of gastrointestinal reflux disease is multifactoral. Integral to the disease process is the refluxate itself. The characteristics and composition of the refluxate are dependent on several physiological variables. The refluxate may contain varying concentrations of acid, pepsin, gas, or contents of duodenal reflux (such as bile acid and pancreatic enzymes). Characteristics such as volume and proximal extent of the refluxate, and the chemical content of this refluxate can strongly influence the risk of symptom perception. Strong acid (pH<4) and duodeno-gastro-oesophageal reflux are also implicated in the development of mucosal damage in the form of oesophagitis, Barrett's metaplasia and oesophageal adenocarcinoma. The manifestation of disease, however, is not entirely reliant on the refluxate, which must be considered in the context of the genetic, environmental and psychological susceptibility of the individual.

Brain activity following esophageal acid infusion using positron emission tomography

AIM: To investigate symptoms and brain activity following esophageal acid infusion.

METHODS: Fifteen healthy volunteers were recruited for the study. Hydrochloric acid (pH 1 and 2) and distilled water (pH 7) were randomly and repeatedly infused into the esophagus. The brain activity was evaluated by positron emission tomography. The severity of heartburn elicited by the infusion was rated on an auditory analog scale of 0-10.

RESULTS: The severity of heartburn following each infusion showed a step-wise increase with increasing acidity of the perfusate. The heartburn scores were significantly higher in the second pH 1 infusion compared with the first infusion. Acid and distilled water infusion induced activation of various brain areas such as the anterior insula, temporal gyrus, and anterior/posterior cingulate cortex. At pH 1 or 2, in particular, activation was observed in some emotion-related brain areas such as the more anterior part of the anterior cingulate cortex, parahippocampal gyrus, or the temporal pole. Strong activation of the orbitofrontal cortex was found by subtraction analysis of the two second pH 1 infusions, with a significant increase of heartburn symptoms.

CONCLUSION: Emotion-related brain areas were activated by esophageal acid stimulation. The orbitofrontal area might be involved in symptom processing, with esophageal sensitization induced by repeated acid stimulation.

Value of barium swallow studies in predicting the response to rabeprazole in elderly patients with laryngopharyngeal reflux disease and nonerosive reflux disease in particular

OBJECTIVES

Laryngopharyngeal reflux disease (LPRD) is an important cause of throat discomfort in the elderly. Our objective was to investigate the usefulness of barium swallow studies for the diagnosis of LPRD.

METHODS

The subjects were 59 patients at least 60 years of age with LPRD suspected on laryngoscopic findings. We evaluated esophageal clearance using a barium swallow study and the upper gastrointestinal tract endoscopic findings of gastroesophageal reflux disease according to the revised Los Angeles classification, and correlated these findings with the effect of rabeprazole, a proton pump inhibitor.

RESULTS

Among subjects with positive reflux findings in the esophageal phase of the barium swallow, rabeprazole was significantly effective (p = 0.0025). To identify nonerosive reflux disease, we analyzed the 50 cases with a negative Los Angeles classification of upper gastrointestinal tract endoscopic findings. Rabeprazole was again significantly effective in patients with positive findings for esophageal reflux (p = 0.0025).

CONCLUSIONS

Among elderly patients with suspected LPRD, there was a positive correlation between impaired esophageal clearance on the barium swallow study and the effectiveness of rabeprazole. The barium swallow study could be a screening test for LPRD in elderly patients with throat discomfort.

Characteristics of gastro-esophageal reflux episodes in Barrett's esophagus, erosive esophagitis and healthy volunteers

BACKGROUND

Gastro-esophageal reflux is considered a major culprit in the pathogenesis of Barrett's esophagus (BE). Still, there is controversy on the role of weakly acidic and weakly alkaline reflux in BE. To compare characteristics of reflux episodes patients with BE, erosive esophagitis (EE), and healthy volunteers (HV).

METHODS

One hundred consecutive patients with BE (75 short-segment BE, 25 long-segment BE), 50 with EE and 48 HV underwent multichannel intraluminal impedance-pH off-therapy. We quantified esophageal acid exposure, characteristics, and proximal extension of reflux episodes.

KEY RESULTS

Total and acid reflux episodes gradually increased from HV [28 (17.5-43) and 18 (8-31)] to EE [73.5 (54-96) and 52 (39-68)], short-segment BE (SSBE) [83 (73.2-131) and 65 (43.3-95)] and long-segment BE (LSBE) [105 (102-187) and 77 (75-107)]. Weakly acidic reflux episodes were significantly higher (P < 0.05) in LSBE [36 (27.5-50.5)] and SSBE [34 (18.5-41)] compared to EE [21.5 (15-37)] and HV [19 (14-25)]. No differences in terms of proportion of acid, weakly acidic and weakly alkaline reflux were found [HV (49%-49%-2%) vs EE (68%-32%-1%) vs SSBE (65%-34%-1%) vs LSBE (69%-30%-1%); P = ns]. In LSBE, a higher percentage of reflux episodes (P < 0.05) reached the proximal esophagus (59%) compared with SSBE (43%).

CONCLUSIONS & INFERENCES

 Barrett esophagus patients have more severe reflux as shown by the number of acid and weakly acidic reflux episodes, re-reflux episodes and proximal migration. Given that PPI change only the pH of the refluxate, the role of weakly acidic reflux in Barrett's patients on acid suppressive therapy warrants further investigation.

Potential role of the cannabinoid receptor CB in the pathogenesis of erosive and non-erosive gastro-oesophageal reflux disease

BACKGROUND

Cannabinoid (CB) receptors have been located in brain areas involved in the triggering of TLESRs as well as in the nodose ganglion from which vagal afferents emanate. The distribution of CB(1) receptors has been investigated in the human gastrointestinal mucosa, as expression of inflammatory process.

AIM

To evaluate the CB(1) expression in oesophageal mucosa.

METHODS

A total of 87 consecutive subjects were enrolled: 10 controls, 39 NERD and 38 erosive oesophagitis. Eight specimens were taken from macroscopically normal mucosa. Five were processed by haematoxylin-eosin, MIB1/CB(1) evaluation and three for the RNA and proteins extraction.

RESULTS

The mean MIB1-LI value was 31% and 22% in NERD and ERD patients, respectively, compared to 68% in the healthy subjects. Mean CB(1)mRNA/GUSB mRNA value of the controls was 0.66, while in GERD patients, it was 0.28. In NERD and ERD, the mean values of CB(1)/GUSB were 0.38 and 0.17, respectively, with highly significant differences between the NERD vs. ERD groups. Semi-quantitative analysis of CB(1) expression, performed with WB, shows in NERD patients a higher CB(1) receptor expression than ERD patients.

CONCLUSIONS

With this study, we showed for the first time the presence of CB(1) receptors in the human oesophageal epithelium.

Quantitative assessment and characterization of visceral hyperalgesia evoked by esophageal balloon distention and acid perfusion in patients with functional heartburn, nonerosive reflux disease, and erosive esophagitis

BACKGROUND AND OBJECTIVES

The role of esophageal hypersensitivity in functional heartburn (FH) with negative pH test, negative symptom index, and the proton pump inhibitor (PPI) failure has not been established. The aim of this study was to investigate the characterization of visceral hyperalgesia evoked by esophageal balloon distention and acid perfusion in patients with FH, nonerosive reflux disease, and erosive esophagitis and further characterize the pathophysiologic mechanism of FH.

METHODS

A total of 21 FH patients (with esophageal acid exposure <3.1% and a symptom index<50% and nonresponse to a therapeutic trial with proton pump inhibitors, 25 Nonerosive reflux disease (NERD) patients (with esophageal acid exposure>4%), 23 erosive esophagitis (EE) patients (LA grade B to D), and 18 healthy controls were recruited in the study. Mechanosensitivity including the initial perception threshold (IPT) and pain threshold (PT) was evaluated by using a Barostat with a double-random staircase distension protocol. Chemosensitivity was graded along a visual analog scale after perfusion of saline and 0.1 N HCl.

RESULTS

The baseline IPTs and PTs were all lower in patients with FH, NERD, and EE than in the controls (all P<0.01). In addition, the baseline PT in FH patients was significantly lower than those in NERD (P=0.015) and EE patients (P<0.001). After acid perfusion, the mean symptom intensity scores were significantly greater in patients with FH, NERD, and EE than those in the controls (all P<0.001). The postacid perfusion IPTs in patients with FH, NERD, and EE were all significantly lower than the corresponding baseline values (all P<0.01). The PTs in FH (P=0.026) and EE patients (P<0.001) were significantly lower than the corresponding baseline values. Moreover, the postacid perfusion PT was significantly lower in FH patients than in NERD patients (P<0.001).

CONCLUSIONS

FH patients are more sensitive to mechanical or chemical stimuli than NERD patients. Sensitization of esophageal acid-sensitive chemoreceptors may exert a significant influence on the pressure-sensitive mechanoreceptors, and there is the cooperative interaction in the process of esophageal visceral hyperalgesia.

Characteristics of reflux episodes and symptom association in patients with erosive esophagitis and nonerosive reflux disease: study using combined impedance-pH off therapy

OBJECTIVES

We sought to compare reflux and symptom association patterns in patients with nonerosive reflux disease (NERD), erosive esophagitis (EE), and in healthy volunteers (HVs).

METHODS

Patients with EE and NERD underwent combined impedance-pH monitoring. Normal values were defined on the basis of previously collected data from 48 HVs. We evaluated distal esophageal acid exposure time (AET), number and type of reflux episodes (acid, nonacid), acid and bolus clearance times, proximal extension of reflux episodes, and symptom association probability (SAP).

RESULTS

Distal AET (percentage time, pH<4) was higher (P<0.01) in 58 EE patients (median 7.4%, 25-75th percentile 4.2-9.9%) compared with 168 NERD patients (4.2% (1.2-6.4%)) and 48 HVs (0.7% (0.2-1.4%)). Patients with EE and NERD had a higher (P<0.01) number of acid reflux episodes compared with HVs (51 (37-66) vs. 34 (22-51) vs. 17 (8-31); P<0.05), but a similar number of nonacid reflux episodes (22 (15-39) vs. 23 (15-38) vs. 18 (14-26); P=NS). The percentage of reflux episodes reaching the proximal esophagus was higher (P<0.01) in EE patients (57% (45-73%)) than in NERD patients (45% (36-60%)) and HVs (33% (19-46%)). A positive SAP for heartburn or regurgitation was found in 161 of 168 (96%) NERD and 54 of 58 (93%) EE patients (P=NS).

CONCLUSIONS

Acid reflux episodes, volume, and acid clearance are important factors in the pathogenesis of reflux-induced lesions. Nonacid reflux contributes less to esophageal mucosa damage, but is involved in the development of reflux symptoms in both NERD and EE patients.

The prokinetic effect of mosapride citrate combined with omeprazole therapy improves clinical symptoms and gastric emptying in PPI-resistant NERD patients with delayed gastric emptying

BACKGROUND

Previous studies have shown that non-erosive reflux disease (NERD) patients are less sensitive to proton pump inhibitor (PPI) treatment than patients with erosive reflux disease. The aim of this study was to investigate whether treatment with prokinetics in addition to omeprazole therapy would improve clinical symptoms, gastric emptying and esophageal peristalsis in PPI-resistant NERD patients with or without delayed gastric emptying.

METHODS

Subjects were 64 consecutive patients presenting with typical symptoms of PPl-resistant NERD (n = 44) and 20 healthy volunteers. PPI-resistant NERD patients underwent mosapride citrate (15 mg/day) and omeprazole (20 mg/day) co-therapy for 12 weeks. We evaluated the clinical symptoms as well as gastric emptying and esophageal manometry before and after combined therapy. We measured both acylated- and des-acylated plasma ghrelin levels by the ELISA method. The primary endopoint was to investigate whether co-administration of mosapride citrate and omeprazole would improve clinical symptoms and gastric emptying in PPI-resistant NERD patients with delayed gastric emptying.

RESULTS

T (max) value in PPI-resistant NERD patients was significantly higher than in healthy volunteers. Combination therapy with the prokinetic agent mosapride citrate and omeprazole significantly improved reflux symptoms and T (max) value in T (max) > 65 min NERD patients. Co-therapy also significantly reduced des-acylated-ghrelin levels in NERD patients with delayed gastric emptying.

CONCLUSIONS

Administration of mosapride citrate in addition to omeprazole improved gastro-esophageal reflux and gastric emptying in PPI-resistant NERD patients with delayed gastric emptying.

Review article: sleep-related gastro-oesophageal reflux as a distinct clinical entity

BACKGROUND

Many patients with chronic gastro-oesophageal reflux disease (GERD) have frequent nighttime heartburn as well as sleep-related gastro-oesophageal reflux (GOR). Sleep-related GOR has been shown to play an important role in the development of oesophagitis and other complications of GOR.

AIM

To present a conceptual argument that nighttime heartburn and associated sleep-related GOR should be recognized as a distinct clinical entity deserving special attention with regard to the diagnosis and treatment of GERD.

METHODS

The data presented come from surveys of GERD patients as well as from physiological studies to include studies monitoring oesophageal pH and spontaneous reflux events during polysomnographically (PSG) monitored sleep.

RESULTS

Evidence is presented to show that nighttime heartburn is prevalent and its occurrence separates patients from those who have heartburn most exclusively in the daytime. The evidence presented also supports the notion that nighttime heartburn sufferers have a more complicated disease and they have a greater risk of developing oesophagitis and other respiratory complications. The data also show that responses to acid mucosal contact are quite different during sleep compared to responses measured during the waking state.

CONCLUSIONS

Nighttime heartburn and GOR represent a distinct clinical entity which deserves specific attention in the diagnosis and optimal treatment of GERD.

Role of the gastric refluxate in gastroesophageal reflux disease: acid, weak acid and bile

The role of acid, weak/nonacid, and bile in the genesis of esophageal mucosal damage and reflux symptoms is complex. Acid combined with pepsin and unconjugated bile acids are critical to the development of esophagitis and Barrett's esophagus. Acid alone may be the principal factor in determining the severity of esophagitis. Weak acid or nonacid reflux does not cause esophageal damage or damage to adjacent organs, such as the larynx or lungs. The primary cause of heartburn and regurgitation is acid reflux, but a minority of symptoms (5%-15%) can be triggered by weak acid or bile reflux. The role is changed among patients on proton pump inhibitors with persistent symptoms, where the majority of symptoms are now due to weak acid or bile reflux. The proximal extent of the reflux, regardless of its acidity, seems to be the key to reflux symptoms.

Comparison of the different characteristics of sensed reflux events among different heartburn groups

BACKGROUND AND AIM

Presently, there are no studies comparing sensed acid reflux event (SARE) characteristics among different heartburn groups. Our aim was to compare the different esophageal acid reflux characteristics of an SARE among the different heartburn groups.

METHODS

Patients with heartburn underwent endoscopy and pH testing and were stratified into 3 groups: erosive esophagitis (EE), nonerosive reflux disease (NERD), and functional heartburn (FH). Patients underwent esophageal pH testing using a 4-sensor pH probe, with the most distal pH sensor positioned 1 cm> lower esophageal sphincter (LES).

RESULTS

Twenty-two patients had EE, 15 NERD, and 13 FH (M/F: 20/2, 12/3, 5/8, mean age: 51.5+/-3.7, 50.1+/-4.2, 50.3+/-3.8, respectively). The percentage of SAREs at 1 cm>LES that had reached 16 cm>LES was significantly higher in the FH group compared with NERD and EE (P<0.05). EE demonstrated the lowest nadir during an SARE and NERD the most acid reflux events before an SARE (up to 4 h).

CONCLUSIONS

Patients with FH demonstrated the most SAREs that reached the proximal esophagus. EE patients demonstrated the lowest nadir pH during an SARE and NERD patients the most acid reflux events before an SARE, as compared with the other heartburn groups.

Predictors of heartburn resolution and erosive esophagitis in patients with GERD

OBJECTIVES

The primary objective was to assess gastroesophageal reflux disease (GERD) symptom resolution rates with esomeprazole by erosive esophagitis (EE) status, and the secondary objective was to evaluate potential predictors of the presence of EE and heartburn resolution.

BACKGROUND

Patients with GERD who have EE have higher reported symptom resolution rates than those with nonerosive reflux disease (NERD) when treated with proton pump inhibitors (PPIs).

STUDY

This open-label multicenter study included adults with GERD symptoms. Patients were stratified by EE status after endoscopy and received once-daily esomeprazole 40 mg for 4 weeks. Questionnaires determined symptom response rates, and baseline predictors of EE or heartburn resolution were evaluated. Potential predictors, including years with GERD, history of EE, and time to relief with antacids, were examined.

RESULTS

Heartburn resolution rates at 4 weeks were higher for patients with EE than NERD (69% [124/179] vs. 48% [85/177]; p < 0.0001). Multivariate models had moderate predictive ability for EE (c-index, 0.76) and poor predictive ability (c-index, 0.57) for heartburn resolution. However, faster heartburn relief with antacid use, particularly within 15 min, was predictive of EE and heartburn resolution.

CONCLUSIONS

Patients with EE have higher heartburn resolution rates than patients with NERD after treatment, although recall bias may be possible. Fast relief with antacid use is predictive of EE and heartburn resolution with a PPI and suggests that a history of antacid relief may provide corroborative evidence to empiric PPI therapy in determining whether patients with heartburn have acid reflux disease. ClinicalTrials.Gov IDENTIFIER: NCT00242736.

Proximal oesophagus: the added value in understanding GORD symptoms

Over the past decade, the approach to the understanding of the mechanisms involved in the aetiology of gastro-oesophageal reflux disease (GORD) symptoms has changed, and growing evidence now supports the concept that visceral hyper-sensitivity to intra-oesophageal stimuli plays a major role. Among the recent advances, one of the more consistent findings is that the contact of the refluxate, either acidic or weakly acidic, with the proximal oesophageal mucosa, is a main determinant of GORD symptoms, particularly in the large majority of patients affected by non-erosive reflux disease. The data reported in the current issue of Neurogastroenterology and Motility by Bredenoord et al., showing only a small proportion of proximal reflux in patients with Barrett's oesophagus, who are less sensitive to gastro-oesophageal reflux, further support the consistency of this finding in the pathogenesis of symptoms. In the light of these results, we shall look forward, in the management of patients, to approaches aimed at restoring the antireflux barrier, hopefully decreasing the amount of reflux and, in turn, its proximal extent.

Relationship between gastro-oesophageal reflux pattern and severity of mucosal damage

The aim of the study is to compare the characteristics of reflux episodes in controls and in patients with various degrees of oesophagitis and Barrett's oesophagus. Ambulatory 24-h impedance-pH tracings were analysed from healthy volunteers, patients with non-erosive reflux disease (NERD), patients with grade A oesophagitis, grade B oesophagitis, grade C or D oesophagitis and patients with a short segment (<2 cm) of Barrett's metaplasia. The number of acid and weakly acidic reflux episodes increased from 25.9 +/- 3.9 to 17.9 +/- 1.5 in the controls, 39.9 +/- 6.3 to 33.4 +/- 5.7 in the patients with NERD, 46.6 +/- 6.2 to 40.4 +/- 9.2 in grade A, 68.2 +/- 9.2 to 49.2 +/- 12.3 in grade B, 79.8 +/- 15.6 to 47.4 +/- 4.6 in grade C/D and 75.1 +/- 7.9 to 37.3 +/- 8.5 in the patients with Barrett. The proportion of reflux episodes that is acidic or alkaline was similar all groups. Comparison with normal values revealed that none of the controls, 40% of the patients with NERD, 50% of the patients with grade A, 80% of the patients with grade B and all patients with grade C/D or Barrett's oesophagus had an abnormally high total number of reflux episodes. In the patients with severe oesophagitis a significantly higher percentage of reflux episodes reached the proximal oesophagus (43.8%) compared to the patients with Barrett's oesophagus (19.2%). With increasing degrees of oesophagitis, patients have more reflux episodes but a large overlap between the groups exists making comparison with normal values of limited relevance. In patients with Barrett's oesophagus fewer reflux episodes reach the proximal oesophagus which might explain their low sensitivity to reflux.

Does the presence of a hiatal hernia affect the efficacy of the reflux inhibitor baclofen during add-on therapy?

OBJECTIVES

Reflux inhibitors, like the gamma-aminobutyric acid type B (GABA(B)) receptor agonist, baclofen, block transient lower esophageal sphincter relaxations (TLESRs) and are proposed as an add-on therapy in patients with proton pump inhibitor (PPI)-resistant gastroesophageal reflux. However, as other mechanisms of reflux become more important in the presence of a hiatal hernia (HH), the efficacy of reflux inhibitors to reduce acid and non-acid exposure may be hampered. Therefore, we compared the effect of baclofen in patients with no HH (-HH) and those with a large HH during PPI treatment.

METHODS

A total of 27 gastroesophageal reflux disease (GERD) patients on PPI were included; 16 had -HH and 11 had a large (> or =3 cm) HH (+HH). During PPI treatment, the effect of baclofen (3 x 20 mg) on acid and non-acid reflux was evaluated in a randomized, double-blind, placebo-controlled cross-over study. Reflux was measured during 24 h using combined esophageal impedance and pH-metry.

RESULTS

The majority of reflux events consisted of both gaseous and liquid reflux with a significant increase in non-acid, mixed reflux episodes in +HH patients compared with those in -HH patients. Acid exposure time was in the normal range in both patient groups during both placebo and baclofen. In this study, baclofen significantly reduced the total number of reflux episodes with 36% in -HH patients and 43% in +HH patients, but did not change the number of acid reflux episodes or total acid exposure time.

CONCLUSIONS

This study shows that baclofen is also effective in patients with GERD with +HH, further underscoring the potential of reflux inhibitors as treatment of GERD.

Clinical trial: the effects of the proton pump inhibitor dexlansoprazole MR on daytime and nighttime heartburn in patients with non-erosive reflux disease

BACKGROUND

The proportion of patients who respond to proton pump inhibitor (PPI) therapy is about 20% lower in those with non-erosive reflux disease (NERD) than in those with erosive oesophagitis.

AIM

To assess efficacy and safety of dexlansoprazole MR, a PPI using Dual Delayed Release technology, in NERD patients.

METHODS

In this 4-week, double-blind, placebo-controlled study, 947 NERD patients randomly received dexlansoprazole MR 30 mg, 60 mg or placebo once daily (QD). The percentages of 24-h heartburn-free days (primary) and nights without heartburn (secondary) were assessed from patients' daily diaries. Investigators also assessed symptoms. Patients completed validated quality of life and symptom severity questionnaires.

RESULTS

Dexlansoprazole MR provided significantly greater median percentages of 24-h heartburn-free days (54.9% and 50.0% for the 30- and 60-mg doses vs. 17.5% for placebo, P < 0.00001) and nights without heartburn (80.8% and 76.9% vs. 51.7%, P < 0.00001 vs. placebo). Dexlansoprazole MR also reduced symptom severity. Quality of life improvements in patients receiving dexlansoprazole MR were consistent with clinical efficacy endpoints. Percentages of patients experiencing treatment-emergent adverse events were similar among groups.

CONCLUSIONS

Dexlansoprazole MR 30 and 60 mg were superior to placebo in providing 24-h heartburn-free days and nights in NERD patients. Treatment was well tolerated.

Reflux profile of Chinese gastroesophageal reflux disease patients with combined multichannel intraluminal impedance-pH monitoring

BACKGROUND AND AIMS

To investigate the reflux profile of Chinese gastroesophageal reflux disease (GERD) patients with the aid of combined multichannel intraluminal impedance-pH (MII-pH) monitoring technique.

METHODS

Consecutive patients presented with GERD symptoms were enrolled to erosive esophagitis (EE) group, non-erosive reflux disease (NERD) group and functional heartburn (FH) group after upper endoscopy, combined MII-pH monitoring and rabeprazole test. Another 20 healthy controls (HC) were recruited.

RESULTS

Sixty-four GERD patients (EE:20, NERD:22, FH:22, HC:20) were enrolled. There were more episodes of liquid reflux and proximal reflux in EE and NERD groups than that in FH and HC groups (P < 0.05). Patients in FH and HC groups had higher proportion of mixed reflux (P = 0.000). The percentage of acid reflux in EE and NERD was much higher, while there was a higher percentage of weakly acidic reflux in FH and HC (P = 0.000). No significant difference was found in MII-pH parameters between groups with and without response to rabeprazole test except recumbent percentage time of esophageal pH value below 4 and episodes of proximal reflux.

CONCLUSION

Erosive esophagitis and NERD patients had more liquid and proximal reflux episodes than FH patients and healthy controls. Acid and liquid reflux was predominant in the former two groups, while weakly acidic and mixed reflux was predominant in the latter two groups.

Regional oesophageal sensitivity to acid and weakly acidic reflux in patients with non-erosive reflux disease

The mechanisms underlying symptoms in non-erosive reflux disease (NERD) remain to be elucidated. Non-erosive reflux disease patients appear to be more sensitive to intraluminal stimula than erosive patients, the proximal oesophagus being the most sensitive. In order to assess regional oesophageal changes in reflux acidity and sensitivity to reflux, according either to the acidity or the composition of the refluxate, combined multiple pH and multiple pH-impedance (pH-MII) was performed in 16 NERD patients. According to multiple pH-metry, 29% and 12% of reflux events reached the middle and proximal oesophagus respectively, and 35% and 19% according to conventional pH-MII (P < 0.05). The per-individual analysis confirmed the difference between the two techniques. According to combined distal and proximal pH-MII, approximately 30% of distal acid reflux became weakly acidic at the proximal oesophagus. In all patients, the frequency of symptomatic refluxes, both acid and weakly acidic, was significantly higher at the proximal, compared with distal oesophagus (25 +/- 8%vs 11 +/- 2% for acid reflux and 27 +/- 8%vs 8 +/- 2% for weakly acidic reflux; P < 0.05). Compared with multiple pH-metry, pH-MII shows a higher sensitivity in the detection of proximal reflux. As approximately 30% of acid reflux becomes weakly acidic along the oesophageal body, to better characterize proximal reflux, in clinical practice, combined proximal pH-impedance monitoring should be used. In NERD patients, the proximal oesophagus seems to be more sensitive to both acid and weakly acidic reflux.

Gastroesophageal reflux disease is associated with the C825T polymorphism in the G-protein beta3 subunit gene (GNB3)

OBJECTIVES

Visceral hypersensitivity is involved in the etiology of reflux symptoms. Familial clustering and twin studies demonstrated a genetic predisposition to gastroesophageal reflux disease (GERD). G-protein-coupled receptors (GPCRs) mediate the response to acid, neurotransmitters and humoral factors modulating esophageal sensory function. Thus, polymorphisms in G-proteins are putative genetic factors contributing to GERD manifestation. A functional polymorphism in the G-protein beta3 subunit gene (GNB3) is associated with functional dyspepsia (FD), in which visceral hypersensitivity is implicated in symptom generation. We evaluated the association of the GNB3 C825T polymorphism with GERD and GERD subgroups classified according to esophageal acid exposure time, symptom-reflux correlation, or coexistence of FD and/or irritable bowel syndrome (IBS) symptoms.

METHODS

In total, 363 GERD patients, defined as having esophageal pH < 4 > or = 6% of time and/or symptom index (SI) > or = 50% or symptom association probability (SAP) > or = 95%, participated. In addition, 373 healthy controls free of gastrointestinal symptoms were studied. Genotyping was performed by molecular beacon assay.

RESULTS

The CT genotype was more prevalent in GERD patients relative to healthy controls (adjusted odds ratio (OR)=1.43, 95% CI 1.04-1.98). GERD patients sensitive to physiological amounts of reflux displayed a higher OR (1.59), as did GERD patients with a positive symptom association score (1.50). The strongest association was detected in patients without concomitant FD and/or IBS symptoms (OR=1.66).

CONCLUSIONS

GERD is associated with GNB3 C825T. The results for GERD subgroups support the hypothesis that enhanced perception of reflux events, as a consequence of the increased signal transduction upon GPCR activation associated with the 825T allele, underlies this association.

Functional heartburn: what it is and how to treat it

Functional heartburn is considered one of the most common functional esophageal disorders. The disorder is more common in young women and is associated with other functional bowel disorders and psychological co-morbidity, primarily somatization. The etiology of functional heartburn remains unknown. Most patients, however, demonstrate esophageal hypersensitivity. Functional heartburn has been identified as the main cause for proton pump inhibitor (PPI) failure in patients with heartburn. Treatment is still a challenge, and patients should be started with PPI treatment. In non-responders, escalation of the PPI dose could be attempted and, if unsuccessful, pain modulators should be prescribed.

Variation of the intercellular space in the esophageal epithelium in response to hydrochloridric acid infusion in patients with erosive esophagitis

The purpose of this study was to compare esophageal infusion with 0.1 N hydrochloric acid (HCl) to esophageal infusion with saline in patients presenting with typical gastroesophageal reflux symptoms and erosive esophagitis.

METHODS

Upper gastrointestinal endoscopy was performed on 44 prospective subjects, 29 of whom were included in the study. Eighteen patients presented with normal esophagi (Control Group "C"), nine of whom were infused with HCl and nine with saline. Eleven patients presented with erosive esophagitis (Lesion Group "L"), five of whom were infused with HCl and six with saline. Biopsies of the esophageal mucosa were collected before and after infusions.

RESULTS

No statistically significant difference was found between the two types of infusions in terms of the dilation of the intercellular space of the esophageal epithelium, regardless of the status of the patient.

CONCLUSIONS

Response to HCl infusion cannot be used as a marker for gastroesophageal reflux disease.

Extraesophageal GERD

The manifestations of gastroesophageal reflux disease (GERD) have been classified into either esophageal or extraesophageal syndromes. Cough, reflux laryngitis, and asthma have been classified as extraesophageal syndromes, whereas reflux chest pain has been classified as a symptomatic syndrome of GERD. In extraesophageal syndromes, patients usually do not display the classic symptoms of reflux, such as heartburn and regurgitation. Upper gastrointestinal endoscopy and pH monitoring, when used to diagnose reflux in patients with symptoms not classic for GERD, have proved to have poor sensitivity and are often not diagnostically helpful. In contrast, an empiric trial of proton pump inhibitors is a well-established, cost-effective tool.

Mechanisms of heartburn

Heartburn is a typical symptom of GERD. The spectrum of diseases associated with GERD includes reflux esophagitis, Barrett's esophagus and nonerosive reflux disease (NERD). Although acid reflux is the classic cause of heartburn in patients with erosive esophagitis, the relationship between acid and heartburn is far from clear, especially in patients with NERD. Strong evidence exists that weakly acidic reflux and/or non-acid-related events have a significant role in the generation of heartburn. In addition to the role of nonacidic refluxate components, activation of mechanoreceptors and chemoreceptors, and a possible role for central and peripheral sensitization, has been described. Although patients with erosive esophagitis respond well to acid-suppressive therapy, the same does not hold true for those with NERD. NERD represents a major clinical problem, and its management remains a challenge. Discussion of NERD focuses on the mechanisms that cause chest pain in this subgroup of patients. Improved understanding of the pathogenesis underlying heartburn in patients with GERD, in particular those with NERD, will shape our understanding of this condition. Such understanding will serve as a platform for further research and allow additional therapies to be developed for this increasingly encountered clinical condition.

Nonerosive reflux disease: a pathophysiologic perspective

Nonerosive reflux disease (NERD) is the most common phenotype of gastroesophageal reflux disease. By definition, patients with NERD have typical reflux symptoms caused by the intraesophageal reflux of gastric contents but have no visible esophageal mucosal injury. This is in contrast to patients with reflux esophagitis, also known as erosive reflux disease, and Barrett's esophagus, who have obvious esophageal mucosal injury on endoscopy. Only 50% of patients with NERD have pathologic esophageal acid contact time (ACT) as detected on 24-hour pH monitoring (ie, NERD-positive). NERD patients with physiologic esophageal ACT and good temporal correlation of symptoms with reflux events (symptom index > 50% or symptom-association probability > 95%) are considered to have esophageal hypersensitivity (ie, NERD-negative). Finally, patients with physiologic esophageal ACT but poor symptom-reflux correlation are now considered to have functional heartburn and not NERD. NERD-positive patients have motor dysfunction and acidic reflux abnormalities that are similar to patients with reflux esophagitis and Barrett's esophagus, whereas NERD-negative patients have minimal abnormalities that are not much different than healthy controls. The histopathologic feature most indicative of NERD is the presence of dilated intercellular spaces within squamous epithelium, an ultrastructural abnormality readily identified on transmission electron microscopy and on light microscopy.

Acid and non-acid reflux patterns in patients with erosive esophagitis and non-erosive reflux disease (NERD): a study using intraluminal impedance monitoring

BACKGROUND

Non-erosive reflux disease (NERD) and erosive esophagitis (EE) are the most common phenotypic presentations of gastroesophageal reflux disease (GERD).

AIM

To assess acid and non-acid reflux patterns in patients with EE and NERD using combined esophageal pH-impedance monitoring.

METHODS

A total of 26 GERD patients off acid-suppressive medication and ten healthy volunteers (HV) underwent upper endoscopy and 24-h pH-impedance monitoring. Analysis of the pH-impedance signals included total reflux time, number of reflux episodes according to gas-liquid composition, and pH (acid, non-acid).

RESULTS

EE was identified in 13 patients and NERD in 13 patients. Pathologic acid reflux was found in 92.3 and 69.2% of patients with EE and NERD, respectively (P = 0.15). When compared to HV, EE patients and NERD patients showed a higher incidence of acid (P = 0.002 and P < 0.001, EE vs. HV and NERD vs. HV, respectively) and non-acid reflux episodes (P = 0.03 and P = 0.001, EE vs. HV and NERD vs. HV, respectively). Mean reflux times, as assessed by both pH-metry and impedance monitoring, and incidence of acid and non-acid reflux episodes were similar in EE and NERD patients. In the supine position, however, EE patients showed a higher incidence of acid (P = 0.048) and liquid reflux episodes (P = 0.07).

CONCLUSION

Whereas EE patients have more acid reflux episodes in the supine position than NERD patients, patients with EE and NERD have similar non-acid reflux patterns. This observation lends support to the notion that non-acid reflux is less damaging to the esophageal mucosa than acid reflux.

Characteristics of symptomatic reflux episodes on Acid suppressive therapy

BACKGROUND

Persistent symptoms on acid suppressive therapy are due to either acid or nonacid gastroesophageal reflux (GER) episodes or are not related to reflux.

AIM

To compare physical and chemical characteristics of GER episodes associated with symptoms in patients on acid suppressive therapy.

METHODS

Patients with persistent symptoms on acid suppressive therapy underwent combined impedance-pH monitoring. Reflux episodes were classified as acid if nadir pH was <4.0, and nonacid if it remained at >/=4.0, separated into liquid-only or mixed (liquid-gas), and considered to reach the proximal esophagus if liquid was present 15 cm above the lower esophageal sphincter (LES). Reflux episodes were considered symptomatic if patients recorded a symptom within 5 min after the reflux episode. Risk factors of symptomatic reflux episodes were identified using multivariable generalized estimating equations (GEEs).

RESULTS

One hundred twenty patients (85 women, median age 54 yr, range 18-85 yr) recorded 3,547 reflux episodes (84.3% nonacid, 50.6% mixed), of which 468 (13.2%) were symptomatic. Based on multivariable GEE analysis with episode-level symptom status (symptomatic vs nonsymptomatic) as the outcome variable, reflux episode acidity was not significantly associated with symptoms (P= 0.40). Mixed reflux episodes were significantly associated with symptoms relative to liquid-only episodes (odds ratio [OR] 1.49, 95% confidence interval [CI] 1.19-1.87, P= 0.0005), as were reflux episodes reaching the proximal esophagus compared with those reaching the distal esophagus only (OR 1.28, 95% CI 1.06-1.55, P= 0.012).

CONCLUSION

The majority of reflux episodes on acid suppressive therapy are asymptomatic. Reflux episodes extending proximally and having a mixed (liquid-gas) composition are significantly associated with symptoms, irrespective of whether pH is acid (<4) or nonacid (>/=4).

Oesophageal tone and sensation in the transition zone between proximal striated and distal smooth muscle oesophagus

Previous studies have shown that the proximal striated muscle oesophagus is less compliant and more sensitive than the distal smooth muscle oesophagus. Conventional and high resolution manometry described a transition zone between striated and smooth muscle oesophagus. We aimed to evaluate oesophageal tone and sensitivity at the transition zone of oesophagus in healthy volunteers. In 18 subjects (seven men, mean age: 28 years) an oesophageal barostat study was performed. Tone and sensitivity were assessed using stepwise isobaric distensions with the balloon located at transition zone and at distal oesophagus in random order. To study the effect induced on transition zone by a previous distension at the distal oesophagus and vice versa, identical protocol was repeated after 7 days with inverted order. Initial distension of a region is referred to as 'naïf' distension and distension of a region following the distension of the other segment as 'primed' distension. Assessment of three oesophageal symptoms (chest pain, heartburn and 'other') was obtained at the end of every distension step. Compliance was significantly higher in the transition zone than in the distal oesophagus (1.47 +/- 0.14 vs 1.09 +/- 0.09 mL mmHg(-1), P = 0.03) after 'naif' distensions. This difference was not observed during 'primed' distensions. Higher sensitivity at transition zone level was found in 11/18 (61%) subjects compared to 6/18 (33%, P < 0.05) at smooth muscle oesophagus. Chest pain and 'other' symptom were more often induced by distention of the transition zone, whereas heartburn was equally triggered by distension of either region. The transition zone is more complaint and more sensitive than smooth muscle oesophagus.

Correlation between oesophageal acid exposure and dyspeptic symptoms in patients with nonerosive reflux disease

BACKGROUND & AIMS

Oesophageal acidification induces dyspeptic symptoms in healthy individuals. This study aimed to evaluate the correlation between oesophageal acid exposure and dyspeptic symptoms in patients with nonerosive reflux disease.

METHODS

A total of 68 patients with dominant symptoms of heartburn, negative upper gastrointestinal endoscopy and concomitant dyspeptic symptoms participated in the study. The severity of dyspepsia and reflux-related symptoms was evaluated, and 24-h gastro-oesophageal pH-monitoring study was performed in all patients at baseline and after 4 weeks of therapy with esomeprazole 40 mg.

RESULTS

Oesophageal basal acid exposure was pathological in 43 patients and normal in 25 patients, with a similar prevalence and severity of individual dyspeptic symptoms in the two groups. A significant correlation between reflux and dyspepsia scores was observed in the subgroup of patients with normal, but not in those with abnormal pHmetry (r=0.4, P=0.04 and r=0.2 P=0.07, respectively). After esomeprazole, a reduction in severity of dyspepsia (>or=50% with respect to baseline) was observed, independent of improvement of reflux-associated symptoms. Improvement in dyspepsia was, however, similar in patients with normal and abnormal basal acid exposure (14/25 vs. 33/43, respectively, P=NS).

CONCLUSION

Dyspeptic symptoms coexist in a subset of nonerosive reflux disease patients, but prevalence and severity of the symptoms seems to be independent of oesophageal acid exposure.

Functional heartburn, nonerosive reflux disease, and reflux esophagitis are all distinct conditions—A debate: Pro

Gastroesophageal reflux disease (GERD) traditionally has been approached as a spectrum-continuum, suggesting that patients may progress over time and develop a more severe esophageal mucosal involvement. The spectrum-continuum conceptual model had a profound impact on the research priorities in GERD, as well as on proposed diagnostic algorithms and therapeutic strategies. Natural course studies in GERD are almost always retrospective and commonly afflicted with a plethora of shortcomings. Factors that affect quality of natural course studies in GERD include the following: index endoscopy results are taken at face value; antireflux treatment is consumed until index endoscopy and/or offered during the follow-up phase; pathophysiologic, anatomic, and genetic factors are overlooked; and lack of confirmation of the durability of the new esophageal mucosal finding. Functional heartburn is common and likely to affect a large subset of patients presenting with heartburn. Evidence to support progression of functional heartburn to nonerosive reflux disease (NERD), erosive esophagitis, or Barrett's esophagus is very scarce. The largest population-based or longest-duration natural course studies report that only 10% of patients progress from NERD to erosive esophagitis over time. The other GERD patients remained within their respective phenotypic presentations of GERD.

Acid-related oesophageal sensitivity, not dysmotility, differentiates subgroups of patients with non-erosive reflux disease

BACKGROUND

Patients with non-erosive reflux disease can experience reflux symptoms with similar frequency and severity as those with erosive reflux disease. Oesophageal motility and acid sensitivity are thought to influence symptom occurrence.

AIM

To compare the effect of infused hydrochloric acid on oesophageal physiology in patients with non-erosive reflux disease and erosive reflux disease.

METHODS

Twelve healthy controls and 39 patients with reflux disease [14 erosive reflux disease, 11 non-erosive reflux disease with normal (functional heartburn) and 14 non-erosive reflux disease with excess acid exposure] had hydrochloric acid and saline infused into distal and then proximal oesophagus. Oesophageal contraction amplitude, lower oesophageal sphincter pressure and pain intensity were documented at baseline and during each infusion.

RESULTS

Patients with non-erosive reflux disease had higher pain sensitivity to acid than those with erosive reflux disease and controls. Proximal acid infusion caused greater pain than distal in patients with non-erosive reflux disease. Acid and saline sensitivity were more pronounced in patients with functional heartburn. Lower oesophageal sphincter pressure and oesophageal contraction amplitudes were lower in the erosive reflux disease and non-erosive reflux disease groups, but did not change during infusions.

CONCLUSIONS

Patients with non-erosive reflux disease and, to a lesser extent, patients with erosive reflux disease, are sensitive to acid in the oesophagus, being more sensitive to proximal acid. Hypersensitivity is most marked in functional heartburn patients. This acid sensitivity is not associated with motility change.

The prevalence of and risk factors for erosive oesophagitis and non-erosive reflux disease: a nationwide multicentre prospective study in Korea

BACKGROUND

Prospective nationwide multicentre studies that have evaluated endoscopic findings and reflux symptoms using a well-designed questionnaire are very rare.

AIM

To compare the prevalence rates of and risk factors for erosive oesophagitis and non-erosive reflux disease (NERD) in the Korean population.

METHODS

A gastroscopic examination was performed on 25 536 subjects who visited 40 Healthcare Centers for a health check-up. A gastro-oesophageal reflux questionnaire and multivariate analysis were used to determine the risk factors for erosive oesophagitis and NERD.

RESULTS

2019 (8%) and 996 subjects (4%) had erosive oesophagitis and non-erosive reflux disease, respectively; only 58% of subjects with erosive oesophagitis had reflux symptoms. Multivariate analysis showed that the risk factors for erosive oesophagitis and NERD differed, i.e. those of erosive oesophagitis were male, a Helicobacter pylori eradication history, alcohol, body mass index > or =25 and hiatal hernia. In contrast, the risk factors for NERD were female, age <40 and > or =60 vs. 40-59 years, body mass index <23 and a monthly income <$1000, glucose > or =126 mg/dL, smoking, a stooping posture at work and antibiotic usage.

CONCLUSIONS

The prevalence rates of erosive oesophagitis and NERD were 8% and 4%, respectively, in Korean health check-up subjects. The risk factors for erosive oesophagitis and NERD were found to differ, which indicates that their underlying pathogeneses are distinct.

Defective triggering of secondary peristalsis in patients with non-erosive reflux disease

BACKGROUND AND AIM

The pathophysiology of non-erosive reflux disease is poorly understood. Triggering of secondary peristalsis is impaired in patients with erosive esophagitis but data in patients with non-erosive reflux disease are lacking. The aim of this study was to evaluate the difference in esophageal motility between patients with non-erosive reflux disease and healthy subjects.

METHODS

Twenty patients with non-erosive reflux disease, with reflux symptoms occurring more than twice per week, and 20 healthy subjects of comparable age and sex underwent esophageal manometry. Primary peristalsis was tested with 10 swallows of a 5-mL water bolus. Secondary peristalsis was triggered by esophageal distention using a 20-mL air bolus, which was injected rapidly into the mid-esophagus. After 20 s, each stimulus was followed by a dry swallow to clear any residual air and then each stimulus was repeated five times.

RESULTS

Basal lower esophageal sphincter pressure, pressure wave amplitude in the upper, middle and lower esophagus, wave velocity and the rates of successful primary peristalsis were similar in non-erosive reflux disease patients and controls. The rate of triggering of secondary peristalsis in patients with non-erosive reflux disease (median 20%, interquartile range 0-40%) was significantly lower (P < 0.0001) than that in healthy subjects (90%, 70-100%). When secondary peristalsis occurred in patients with non-erosive reflux disease, however, there were no differences in the amplitude and velocity of secondary peristalsis between the groups.

CONCLUSIONS

Triggering of secondary peristalsis is defective in non-erosive reflux disease. This could lead to prolongation of the contact time between refluxed gastric acid and esophageal mucosa thereby leading to symptoms.

Endoscopic appearance of GERD: putative role of cell proliferation

BACKGROUND

Erosive esophagitis is a frequent endoscopic feature in patients with gastro-oesophageal reflux disease. However, most of patients with heartburn/regurgitation have a non-erosive reflux disease. The reason for this heterogeneous impact of gastro-oesophageal reflux disease on oesophageal mucosa is unknown to date.

AIM

To evaluate the cell proliferation status of oesophageal epithelium in both healthy normal subjects and patients with gastro-oesophageal reflux disease with or without erosions.

MATERIALS AND METHODS

All the subjects underwent endoscopy and biopsies were taken at 5 cm from the squamo-columnar junction. Specimens were analysed both at histology and at transmission electron microscopy. Cell proliferation was evaluated by MIB1 immunostaining. Of the 85 subjects were studied, 10 were healthy controls with normal pH-testing and macroscopical, histological and ultrastructural patterns; 37 were patients with erosive esophagitis, and 38 patients with non-erosive reflux disease.

RESULTS

At histology, of the 37 patients affected by erosive esophagitis, 30 had normal mucosa and 7 showed mild oesophagitis. One patient with non-erosive reflux disease showed signs of oesophagitis at histology. At TEM, all patients with gastro-oesophageal reflux disease had ultrastructural patterns of damage i.e. dilations of intercellular spaces (DIS), and all controls had a normal ultrastructural pattern. The mean (+/-SD) MIB1-LI values of normal subjects and non-erosive reflux disease and erosive oesophagitis patients were 62.2% (+/-9.1), 29.7% (+/-7.2) and 16.2% (+/-5.2), respectively; there were significant differences among the three groups (p<0.001).

CONCLUSIONS

Oesophageal mucosa of patients with reflux symptoms presents a decrease in MIB1 immunostaining of 50% and 25% in non-erosive reflux disease and erosive esophagitis patients with respect to normal subjects.

Review article: the pathophysiology of gastro-oesophageal reflux disease

BACKGROUND

Gastro-oesophageal reflux disease (GERD) is a common condition that develops when the reflux of stomach contents causes troublesome symptoms and/or complications.

AIM

To review the current knowledge on the underlying factors contributing to GERD, with particular emphasis on the most recent research.

METHODS

Literature searches were conducted in Medline and EMBASE. The abstracts from recent large congresses were also reviewed to ensure coverage of the latest findings.

RESULTS

The pathophysiological factors causing GERD can be split into those inducing greater exposure of the oesophagus to stomach contents, and those that provide increased perception of reflux or increased mucosal damage. Transient lower oesophageal sphincter relaxations, which are likely to be triggered by gastric distension, appear to be a key physiological cause of GERD. Excessive reflux may also be provoked by impaired oesophageal or gastric clearance mechanisms. Pre-epithelial, epithelial and post-epithelial defences all normally protect the oesophagus from injury, and may be compromised in individuals with GERD. Heartburn could also be caused by oesophageal hypersensitivity as a result of visceral neural pathway dysfunction.

CONCLUSION

The pathophysiology of GERD is multifactorial, and abnormalities in the gastro-oesophageal junction, the stomach, the oesophagus and the nervous system may all contribute to this disease state.

Role of intra-oesophageal impedance monitoring in the evaluation of endoscopic gastroplication for gastro-oesophageal reflux disease

BACKGROUND

In the evaluation of several endoscopic antireflux procedures, a discrepancy in the degree of improvement between symptoms and objective reflux parameters as measured by pH-metry has been reported.

AIM

To assess the additional value of impedance monitoring in the evaluation of endoscopic gastroplication for gastro-oesophageal reflux disease.

METHODS

Eighteen patients with gastro-oesophageal reflux disease were treated with three endoscopic gastroplications, and underwent 24 h pH-impedance monitoring before and 3 months after treatment.

RESULTS

Total reflux exposure time as assessed by pH-metry and impedance monitoring was significantly decreased after treatment (P = 0.047 and <0.001, respectively). When assessed with impedance monitoring, the mean number of reflux episodes was significantly decreased after the procedure (82 vs. 56, pre vs. post, P < 0.001). Furthermore, the mean numbers of liquid and acid reflux episodes in patients with symptomatic improvement were significantly reduced after treatment (P = 0.04 and 0.02, respectively). After treatment, mean volume clearance time (s) and mean number of proximal reflux episodes were significantly decreased (P < 0.001 and 0.002, respectively).

CONCLUSIONS

Impedance monitoring can identify the specific effect of endoscopic gastroplication on the different types of reflux episodes with regard to gas-liquid composition and pH, as well as on volume clearance and the proximal extent of the refluxate.

Developments in pathogenesis and diagnosis of gastroesophageal reflux disease

PURPOSE OF REVIEW

Although gastroesophageal reflux is a common disorder, diagnosis is still imprecise. Moreover, its pathogenesis is incompletely understood. This review summarizes recent progress in diagnosis and our understanding of the pathogenesis of gastroesophageal reflux disease.

RECENT FINDINGS

Recent studies have focused on the pattern of reflux in the distal esophagus, just above the esophago-gastric junction, challenging its importance on the genesis of reflux symptoms. New techniques, such as impedance, could improve the diagnostic yield, especially in patients with nonacid reflux. Esophageal sensitivity and motility, transient lower esophageal sphincter relaxations, and hiatus hernia are important pathogenic mechanisms of reflux disease. Studies showed that obesity plays a role in the pathogenesis of reflux symptoms; a disruption of the esophago-gastric junction (leading to hiatus hernia) could allow reflux to occur. The association between reflux (particularly nonacid) and extraesophageal manifestations of gastroesophageal reflux disease has been further evaluated.

SUMMARY

Improvement of diagnostic techniques and better understanding of the pathogenesis of reflux may lead to new or better therapeutic modalities. Our understanding of some of the risk factors for reflux has been increased. Extra-esophageal manifestations and their association with gastroesophageal reflux are still a very controversial and promising area of research.

Effect of oesophagitis on proximal extent of gastro-oesophageal reflux

Proximal oesophageal acid reflux is increased in gastro-oesophageal reflux disease (GORD) patients with oesophageal and extra-oesophageal symptoms, the latter particularly in presence of oesophagitis. This study was aimed to assess the proximal extent of reflux, both acid and weakly acidic, in GORD patients with and without oesophagitis and to characterize, using an animal model of GORD, the relationship between acute oesophagitis and proximal extent of reflux. Proximal extent of reflux was evaluated during 24-h pH-impedance monitoring in 17 oesophagitis, 27 non-erosive reflux disease (NERD) patients and 10 asymptomatic controls. In five adult cats, reflux events were simulated by intra-oesophageal retrograde injection of a radiopaque solution. Proximal extent of simulated reflux was fluoroscopically assessed before and after inducing acute oesophagitis. The percentage of proximal reflux was 11% in controls, 22% in NERD and 38% in oesophagitis patients (P < 0.05 vs NERD). Weakly acidic reflux showed higher proximal extent in oesophagitis than in NERD patients but it was less proximally propagated than acid reflux. In cats, proximal reflux was significantly increased during acute oesophagitis. Oesophagitis patients show higher proximal extent of reflux, acid and weakly acidic, when compared with NERD patients and controls. In the experimental model, acute oesophagitis favours proximal migration of simulated reflux.

Electrophysiological characterization of vagal afferents relevant to mucosal nociception in the rat upper oesophagus

Emerging evidence indicates a nociceptive role of vagal afferents. A distinct oesophageal innervation in the rat, with muscular and mucosal afferents travelling predominantly in the recurrent (RLN) and superior laryngeal nerve (SLN), respectively, enabled characterization of mucosal afferents with nociceptive properties, using novel isolated oesophagus-nerve preparations. SLN and RLN single-fibre recordings identified 55 and 14 units, respectively, with none conducting faster than 8.7 m s(-1). Mucosal response characteristics in the SLN distinguished mechanosensors (n = 13), mechanosensors with heat sensitivity (18) from those with cold sensitivity (19) and a mechanoinsensitive group (5). The mechanosensitive fibres, all slowly adapting, showed a unimodal distribution of mechanical thresholds (1.4-128 mN, peak approximately 5.7 mN). No difference in response characteristics of C and Adelta fibres was encountered. Mucosal proton stimulation (pH 5.4 for 3 min), mimicking gastro-oesophageal reflux disease (GORD), revealed in 31% of units a desensitizing response that peaked around 20 s and faded within 60 s. Cold stimulation (15 degrees C) was proportionally encoded but the response showed slow adaptation. In contrast, the noxious heat (48 degrees C) response showed no obvious adaptation with discharge rates reflecting the temperature's time course. Polymodal (69%) mucosal units, > 30% proton sensitive, were found in each fibre category and were considered nociceptors; they are tentatively attributed to vagal nerve endings type I, IV and V, previously morphologically described. All receptive fields were mapped and the distribution indicates that the posterior upper oesophagus may serve as a 'cutbank', detecting noxious matters, ingested or regurgitated, and triggering nocifensive reflexes such as bronchoconstriction in GORD.

Review article: acidity and volume of the refluxate in the genesis of gastro-oesophageal reflux disease symptoms

BACKGROUND

A number of mechanisms, other than acid reflux, may be responsible for the symptoms of gastro-oesophageal reflux disease.

AIM

To assess the importance of non-acid reflux mechanisms.

METHODS

This review is based on presentations and discussion at a workshop, where specialists in the field analysed data relating to these mechanisms.

RESULTS

Weakly acidic reflux, pH (4-7), detected with impedance-pHmetry is associated with regurgitation and atypical gastro-oesophageal reflux disease symptoms. It is not clear whether pepsin and trypsin can elicit symptoms, but bile can elicit heartburn. The magnitude of reflux-induced oesophageal distension can be determined by high frequency ultrasonography and is not reduced by proton pump inhibition, suggesting that persisting symptoms 'on' a proton pump inhibitor may still be due to oesophageal distension by non-acidic reflux. Exaggerated longitudinal muscle contraction can induce non-acid-related heartburn. Preliminary studies showed a positive effect of baclofen, surgery or endoscopic procedures to reduce weakly acidic reflux.

CONCLUSION

Mechanisms other than acid reflux are involved in some of the symptoms of gastro-oesophageal reflux disease. Controlled outcome studies are needed to clarify their roles and the indications for antireflux procedures in patients with persistent symptoms whilst 'on' a proton pump inhibitor.

Dilated intercellular spaces and acid reflux at the distal and proximal oesophagus in patients with non-erosive gastro-oesophageal reflux disease

BACKGROUND

Acid exposure of proximal oesophagus and dilated intercellular space diameters of oesophageal epithelium are relevant in the perception of gastro-oesophageal reflux.

AIM

To explain the relationship between gastro-oesophageal reflux disease symptoms, acid exposure and intercellular space diameter along the oesophageal epithelium and to assess time-related variability of intercellular space diameter.

METHODS

Thirty-three non-erosive reflux disease (NERD), six erosive oesophagitis patients and 12 asymptomatic controls underwent oesophageal manometry and 24-h dual-channel oesophageal pH-monitoring following endoscopy. Biopsies were taken 5 cm above the LES and 10 cm below the UES, at comparable levels, as pH sensors. A total of 100 intercellular space diameters per patient/control were measured blindly at transmission electron microscopy. In 15 patients, the investigation was repeated after 1 year.

RESULTS

In all NERD patients, acid exposure was higher at mid-proximal oesophagus (P < 0.01) and mean intercellular space diameters, at distal and mid-proximal oesophagus, was three- and twofold higher (1.5 and 0.82 micro m, respectively) compared with controls. Intra-patient intercellular space diameter values were stable over time, not overlapping with those of controls.

CONCLUSIONS

Dilation of intercellular space diameter occurs along the distal and proximal oesophageal epithelium in NERD patients and could be responsible for the enhanced perception of proximal acid reflux. This finding appears to be time-reproducible and to represent a sensitive, histopathological marker of NERD.

Assessment of dietary nutrients that influence perception of intra-oesophageal acid reflux events in patients with gastro-oesophageal reflux disease

BACKGROUND

Gastro-oesophageal reflux disease symptoms are most commonly reported postprandially, suggesting that some diet components are likely to induce symptoms more than others.

AIMS

To determine which of the various dietary nutrients is a strong predictive factor for symptom generation in association with an acid reflux event.

METHODS

Subjects with typical heartburn symptoms were evaluated by the gastro-oesophageal reflux disease Symptom Checklist, demographics questionnaire, upper endoscopy and pH testing. During the pH study, patients completed a detailed 24-h dietary intake record. This included time of meals, description of food components and the amount and type of food preparation.

RESULTS

Fifty gastro-oesophageal reflux disease patients completed all stages of the study. A total of 112 (78%) symptoms were considered as sensed reflux event. Body mass index did not correlate with having perceived reflux. Patients who consumed more cholesterol, saturated fatty acids and had more percentage calories from fat were significantly more likely to experience a perceived reflux event. Regression analysis and beta-coefficient were specifically significant for cholesterol.

CONCLUSION

Of all dietary nutrients, cholesterol enhances the most the perception of intra-oesophageal acid reflux events in patients with gastro-oesophageal reflux disease.

The Montreal definition and classification of gastroesophageal reflux disease: a global evidence-based consensus

OBJECTIVES

A globally acceptable definition and classification of gastroesophageal reflux disease (GERD) is desirable for research and clinical practice. The aim of this initiative was to develop a consensus definition and classification that would be useful for patients, physicians, and regulatory agencies.

METHODS

A modified Delphi process was employed to reach consensus using repeated iterative voting. A series of statements was developed by a working group of five experts after a systematic review of the literature in three databases (Embase, Cochrane trials register, Medline). Over a period of 2 yr, the statements were developed, modified, and approved through four rounds of voting. The voting group consisted of 44 experts from 18 countries. The final vote was conducted on a 6-point scale and consensus was defined a priori as agreement by two-thirds of the participants.

RESULTS

The level of agreement strengthened throughout the process with two-thirds of the participants agreeing with 86%, 88%, 94%, and 100% of statements at each vote, respectively. At the final vote, 94% of the final 51 statements were approved by 90% of the Consensus Group, and 90% of statements were accepted with strong agreement or minor reservation. GERD was defined as a condition that develops when the reflux of stomach contents causes troublesome symptoms and/or complications. The disease was subclassified into esophageal and extraesophageal syndromes. Novel aspects of the new definition include a patient-centered approach that is independent of endoscopic findings, subclassification of the disease into discrete syndromes, and the recognition of laryngitis, cough, asthma, and dental erosions as possible GERD syndromes. It also proposes a new definition for suspected and proven Barrett's esophagus.

CONCLUSIONS

Evidence-based global consensus definitions are possible despite differences in terminology and language, prevalence, and manifestations of the disease in different countries. A global consensus definition for GERD may simplify disease management, allow collaborative research, and make studies more generalizable, assisting patients, physicians, and regulatory agencies.

The pharmacodynamic effect of omeprazole 10 mg and 20 mg once daily in patients with nonerosive reflux disease in Japan

BACKGROUND

To evaluate the pharmacodynamic effect, efficacy, and safety of omeprazole 10 mg and 20 mg once daily in patients with nonerosive reflux disease (NERD) in Japan.

METHODS

A total of 37 patients were randomized to omeprazole 10 mg or omeprazole 20 mg once daily for 4 weeks. Eligible patients had a history of moderate-to-severe heartburn for 2 days or more per week during the last 1 month or longer prior to the study screening, grade M or grade N on Hoshihara's modification of the Los Angeles classification (i.e., no sign of mucosal break on esophagogastroduodenoscopy), and heartburn episodes for 2 days or more per week during the last week of the observation period while taking antacids. Ambulatory 24-h intraesophageal pH was monitored on the day before treatment and on the last day of treatment. The occurrence of a heartburn episode was recorded during pH monitoring. The primary endpoint was the change in the percentage of time with intraesophageal pH < 4 during the 24-h period before and after omeprazole treatment.

RESULTS

Both omeprazole 10 mg and omeprazole 20 mg once daily reduced the percentage of time with intraesophageal pH < 4. The percentage reduction in time with intraesophageal pH < 4 after treatment with omeprazole was associated with a reduced number of heartburn episodes. Patients with grade M or grade N esophagus had similar pH profiles and NERD characteristics (e.g., pH holding time, symptom index) and comparable responses to omeprazole. No serious, drug-related adverse events were reported.

CONCLUSIONS

Omeprazole 10 mg or 20 mg reduces the percentage of time with intraesophageal pH < 4, is efficacious, and is well tolerated in patients with NERD in Japan, regardless of the patient's endoscopic classification.

Effect of hiatal hernia on proximal oesophageal acid clearance in gastro-oesophageal reflux disease patients

BACKGROUND

Proximal acid reflux is common in gastro-oesophageal reflux disease and is a determinant of symptoms. Patients with hiatal hernia complain of more symptoms than those without and are less responsive to proton-pump inhibitors.

AIM

To evaluate the role of hiatal hernia on spatiotemporal characteristics of acid reflux.

METHODS

Thirty seven consecutive gastro-oesophageal reflux disease patients underwent endoscopy, videofluoroscopy, manometry and multichannel 24-h pH test. Data were compared with those of 15 asymptomatic controls. Multivariate linear regression was used for statistical analysis.

RESULTS

At videofluoroscopy, hiatal hernia was found in 16 of 37 patients. The mean size of hiatal hernia was 3.4 cm. Patients showed significantly prolonged acid clearance time, both at proximal and distal oesophagus, compared with controls. Hiatal hernia patients showed a significantly delayed acid clearance, along the oesophageal body, compared with non-hiatal hernia patients. The prolonged acid exposure was maintained during upright and supine position. The presence of hiatal hernia significantly predicted acid clearance delay in the distal and proximal oesophagus [at 10 cm below upper oesophageal sphincter: Delta + 2.5 min (95% confidence interval: 0.4-4.5); P < 0.02].

CONCLUSIONS

The presence of hiatal hernia is a strong predictor of more prolonged proximal oesophageal acid exposure and clearance. Hiatal hernia is likely to play a role in the pathophysiology of gastro-oesophageal reflux disease symptoms, and should be taken into greater consideration in the treatment strategies of the disease.

Review article: the role of acid suppression in patients with non-erosive reflux disease or functional heartburn

When patients with the typical reflux symptoms of heartburn, regurgitation, or both, undergo endoscopy, up to 75% will not have endoscopic oesophagitis or evidence of Barrett's oesophagus. These patients have been described as having endoscopic negative or, more commonly, non-erosive reflux disease (NERD). Patients without oesophagitis, but with a positive pH test, can be diagnosed with gastro-oesophageal reflux disease (GERD). Some experts also consider a response to proton pump inhibitor therapy as proof of GERD in a patient with the correct symptoms and a negative endoscopy. Patients with normal acid exposure, but who report symptoms with a majority of their reflux episodes documented during an ambulatory pH study, have also been considered to have NERD, although others have labelled them as having 'functional heartburn'. Finally, there are some patients who have reflux symptoms and respond to reflux therapy, but have no demonstrable reflux by either endoscopy or ambulatory reflux testing. Whether these patients are part of the GERD spectrum or have another diagnosis is not clear. It seems that the most widely used definition of functional disease (the Rome II criteria) would include these patients as having functional heartburn, as it was defined as 'greater than or equal to 12 weeks of either continuous or intermittent symptoms of burning retrosternal discomfort or pain without pathologic GERD, achalasia, or other motility disorders with a recognized pathologic basis'. This article reviews potential differences in pathophysiology between erosive oesophagitis and NERD; explores whether symptoms can help distinguish NERD patients from erosive oesophagitis patients; and explores the evaluation and therapy of these patients.