Gastric acid and pepsin secretion in patients with Barrett's esophagus and appropriate controls

Assessment of the Acute Effects of Carbonated Beverage Consumption on Symptoms and Objective Markers of Gastric Reflux

Previous studies have suggested that carbonated beverages may cause gastro-oesophageal reflux. Pepsin (the major enzyme secreted by the stomach) has been suggested to be an objective, acute marker of a reflux event. This pilot study aimed to investigate whether intake of carbonated beverages could affect pepsin concentration in saliva or reflux symptoms. This was assessed by a randomised, crossover trial where participants consumed 330 mL of beverage (carbonated cola, degassed cola or water) at separate visits. Saliva samples and symptom questionnaires were collected at baseline and over the 30 min postprandial period. Pepsin was detected in all saliva samples. No difference was found in the salivary pepsin concentrations between treatments at all time points. There were significantly higher scores (p > 0.05) for feelings of fullness, heartburn, urge to belch and frequency of belches after ingestion of carbonated cola than degassed cola and water. The ingestion of carbonated beverages did not appear to increase postprandial pepsin concentration in saliva compared to other beverages but did evoke higher levels of reflux-related symptoms such as fullness, heartburn and belching. This suggests carbonated beverages may cause symptoms associated with reflux but do not drive detectable levels of gastric juice to reach the oral cavity.

Barrett esophagus in Asia: same disease with different pattern

Barrett esophagus (BE) is considered to develop as a result of chronic gastroesophageal reflux disease (GERD) and to predispose to esophageal adenocarcinoma (EAC). However, the disease pattern of BE in Asia differs from that observed in the West. For example, in the West, the prevalence rates of BE and EAC have progressively increased, whereas although the prevalence rate of GERD is increasing in Asia, the prevalence rates of BE and EAC have remained low in most Asian countries. GERD, hiatal hernia, old age, male sex, abdominal obesity (visceral obesity), smoking, alcohol consumption, and kyphosis are known risk factors for BE in Asia, and most Asian patients have short-segment BE. Helicobacter pylori infection is more prevalent in Asia than in the West. We suggest larger studies with a prospective design be conducted to elaborate further the different patterns of BE in Asia.

Acid-induced COX-2 expression and prostaglandin E2 production via activation of ERK1/2 and p38 MAPK in cultured feline esophageal smooth muscle cells

Cyclooxygenase (COX)-2 is known to play an important role in inflammatory conditions such as reflux esophagitis resulting from acid reflux. In this study, we tested whether an acidic medium (pH 4.0) induces an increase in COX-2 expression or PGE(2) production, and explored the implication of mitogen-activated protein kinases (MAPKs) activation in these responses in cultured cat esophageal smooth muscle cells. Acidic cytotoxicity was assessed and expression changes in COXs or phosphorylated MAPKs were analyzed by Western blotting. PGE(2) production was measured by immunoassay. No significant decrease in cell viability was observed for 6 h exposure to acidic medium. COX-2 expression and PGE(2) production significantly increased to maximal levels at 6 h exposure to acidic medium. The cells also exhibited significant activation of ERK1/2 and p38 MAPK, but not JNK within 10 min under acidic medium. The increments of COX-2 expression and PGE(2) production by acidic medium were decreased by pretreatment with PD98059 or SB202190, respectively. These results suggest that acidic environments may enhance the COX-2 expression and PGE(2) production through activation of ERK1/2 and p38 MAPK in the cultured cat esophageal smooth muscle cells.

The mechanism of MAP kinase activation under acidic condition in feline esophageal smooth muscle cells

Reflux esophagitis results from repeated exposure of the esophagus to acidic gastric juice or bile-containing duodenal contents. In Barrett's adenocarcinoma, acid increases proliferation via ERK and p38 MAPK activation. This study was focused on determination of the mechanism(s) underlying MAPKs (ERK 1/2, p38 MAPK, and JNK) activation induced by acidic medium at pH 4 in normal feline primary cultured esophageal smooth muscle cells (FESMCs). We detected ERK 1/2 and p38 MAPK phosphorylation after exposure to pH 4 or neutral media in the presence or absence of several inhibitors and quantified the MAPK levels using western blotting analysis and densitometry. Acidic medium markedly increased the phosphorylation of ERK 1/2 and p38 MAPK within 10 min. Acid-induced ERK 1/2 and p38 MAPK activation was inhibited by pertussis toxin (PTX-sensitive G(i/o) protein inhibitor), DEDA (phospholipase (PL) A(2) inhibitor), ρCMB (PLD inhibitor), GF109203X (protein kinase C (PKC) inhibitor) and D609 (phosphatidylcholine-specific PLC inhibitor). But, genistein (tyrosine kinase inhibitor), forskolin (adenylate cyclase activator) and U73122 (phosphatidylinositol-specific PLC inhibitor) had no effect on acid-induced ERK1/2 and p38 MAPK activation. These findings indicate that the activation of ERK 1/2 and p38 MAPK pathways by acidic conditions, at least in part, may be mediated by activation of the G(i/o) protein coupled receptors, PC-PLC, PLD, PLA(2), and PKC in FESMCs.

The effects of high-dose esomeprazole on gastric and oesophageal acid exposure and molecular markers in Barrett's oesophagus

BACKGROUND

Acid reflux is often difficult to control medically.

AIM

To assess the effect of 40 mg twice daily esomeprazole (high-dose) on gastric and oesophageal pH and symptoms, and biomarkers relevant to adenocarcinoma, in patients with Barrett's oesophagus (BO).

METHODS

Eighteen patients, treated with proton pump inhibitors as prescribed by their treating doctor, had their therapy increased to high-dose esomeprazole for 6 months.

RESULTS

At entry into the study, 9/18 patients had excessive 24-h oesophageal acid exposure, and gastric pH remained <4 for >16 h in 8/18. With high-dose esomeprazole, excessive acid exposure occurred in 2/18 patients, and gastric pH <4 was decreased from 38% of overall recording time and 53% of the nocturnal period to 15% and 17%, respectively (P < 0.001). There was a reduction in self-assessed symptoms of heartburn (P = 0.0005) and regurgitation (P < 0.0001), and inflammation and proliferation in the Barrett's mucosa. There was no significant change in p53, MGMT or COX-2 expression, or in aberrant DNA methylation.

CONCLUSIONS

High-dose esomeprazole achieved higher levels of gastric acid suppression and control of oesophageal acid reflux and symptoms, with significant decreases in inflammation and epithelial proliferation. There was no reversal of aberrant DNA methylation.

Barrett's esophagus is characterized by the absence of Helicobacter pylori infection and high levels of serum pepsinogen I concentration in Japan

BACKGROUND AND AIM

It has been reported that patients with Barrett's esophagus (BE) may have gastric acid hypersecretion. Serological markers such as serum pepsinogen or gastrin have been used to estimate the gastric secretory function. The aim of this study was to compare the serum pepsinogen and gastrin concentrations in view of Helicobacter pylori infection status between BE patients and the controls.

METHODS

Thirty-six patients with long-segment BE were enrolled in this study. Three age- and sex-matched controls were assigned to each patient. Serum pepsinogen and gastrin concentrations were measured by radioimmunoassay and H. pylori infection was determined by histology and serum IgG antibodies.

RESULTS

Helicobacter pylori infection was present in 4 of 36 patients (11%) with BE and in 80 of 108 controls (74%), being less prevalent in BE patients than in the controls (P < 0.0001). When examined in the H. pylori-negative subjects, both the serum pepsinogen I and pepsinogen II concentrations in BE patients were significantly higher than those in the controls (mean pepsinogen I:BE 51.0 +/- 14.0 ng/mL vs control 38.9 +/- 13.5 ng/mL, P = 0.0012; mean pepsinogen II:BE 10.8 +/- 4.0 ng/mL vs control 7.9 +/- 2.0 ng/mL, P = 0.0097). There was no significant difference in the serum gastrin levels between BE patients and the controls irrespective of the H. pylori infection status.

CONCLUSIONS

Most of the Japanese BE patients are characterized by the absence of H. pylori infection and high levels of serum pepsinogen. Determination of the serum pepsinogen level in combination with the H. pylori infection status could be a useful serological marker for BE screening.

Barrett's esophagus: pathogenesis, treatment, and prevention

Esophageal adenocarcinoma is the most common type of esophageal cancer seen in the United States and Western Europe. Barrett's esophagus (BE) is a well-known risk factor for esophageal adenocarcinoma and is believed to be found in 6% to 12% of patients undergoing endoscopy for gastroesophageal reflux disease and in more than 1% of all patients undergoing endoscopy. This article focuses on the pathogenesis, treatment, and prevention of BE.

Immune and Inflammatory Responses in GERD and Lansoprazole

The exact pathophysiological mechanisms responsible for gastroesophageal reflux disease (GERD) remain unclear. Recent studies have shown that mucosal immune and inflammatory responses, characterized by specific cytokine and chemokine profiles, may underlie the diverse esophageal phenotypes of GERD. Interleukin 8 (IL-8), a representative chemokine, mediates neutrophil trafficking via its receptors, mainly CXCR-1. The IL-8 mRNA and protein levels are increased in the esophageal mucosa, not only in reflux esophagitis (RE), but also in endoscopy-negative GERD (NERD), through activation of nuclear factor-kappaB (NF-kappaB), which is a pivotal transcription factor. Mucosal IL-8 concentrations have been found to parallel the endoscopic severity of RE, implying that this cytokine is a key player in the development of GERD. The mucosal levels of the C-C chemokines, macrophage chemoattractant protein 1 (MCP-1) and regulated on activation normal T-cell-expressed and presumably secreted (RANTES), which primarily attract monocytes and lymphocytes to the site of inflammation, respectively, are also elevated in RE. The secreted levels of IL-8 and IL-1beta, a prototype of proinflammatory cytokine, are maximal at the proximal segment within Barrett esophagus (BE) tissue. The expression of the two pleiotrophic proinflammatory cytokines, IL-6 and tumor necrosis factor alpha, is enhanced in the intestinal epithelium of BE, which places this epithelium at a higher risk for developing malignancy. BE is characterized by a distinct Th-2 predominant cytokine profile (IL-4 and -10), compared to the proinflammatory nature of RE (interferone-gamma). Treatment with a proton pump inhibitor, lansoprazole reduces the mucosal levels of IL-8 mRNA and protein in GERD, including RE and NERD. This may occur in part through an anti-inflammatory action of proton pump inhibitors beyond gastric acid inhibition.

Gastric and esophageal pH in patients with Barrett's esophagus treated with three esomeprazole dosages: a randomized, double-blind, crossover trial

BACKGROUND

It has been suggested that patients with Barrett's esophagus (BE) are unusually resistant to the antisecretory effects of proton pump inhibitors (PPIs).

OBJECTIVES

To compare intragastric and intraesophageal acidity in patients with BE receiving esomeprazole 40 mg three times daily (t.i.d.), esomeprazole 40 mg twice daily (b.i.d.), and esomeprazole 20 mg t.i.d.

METHODS

In this randomized, double-blind, three-way crossover study, patients with long-segment BE received each of the three esomeprazole dosages for 5 days separated by 10-14-day washout periods. Intragastric and intraesophageal pHs were measured for 24 h on day 5.

RESULTS

Among 31 patients with evaluable pH data, intragastric pH was >4.0 for 88.4%, 81.4%, and 80.4% of day 5 after treatment with esomeprazole 40 mg t.i.d., 40 mg b.i.d., and 20 mg t.i.d., respectively. Esomeprazole 40 mg t.i.d. was significantly more effective than the other dosages (p < 0.01). Intraesophageal pH was <4.0 for mean values of <5% of the monitoring period with all the three dosing regimens, but esophageal pH remained <4.0 for >5% of the time in 16%, 23%, and 19% of patients receiving esomeprazole 40 mg t.i.d., 40 mg b.i.d., and 20 mg t.i.d., respectively. All dosages were well tolerated.

CONCLUSIONS

All the three esomeprazole dosages significantly decreased intragastric acidity and reduced esophageal acid exposure to mean normal values in the total group of patients with BE. However, abnormal esophageal acid exposure continued in 16-23% of patients despite the significant decrease in gastric acidity. These results suggest that the apparent "PPI resistance" described in patients with BE may be caused by their profound reflux diathesis rather than by gastric resistance to the antisecretory effects of PPIs.

New Molecular Concepts of Barrett’s Esophagus: Clinical Implications and Biomarkers

Barrett's esophagus (BE) represents the most serious histological consequence of gastroesophageal reflux disease (GERD) that develops in 5-10% of patients with GERD. Given that BE is the only known precursor to esophageal adenocarcinoma (EA), a systematic endoscopic biopsy protocol can detect EAs at an early stage. However, endoscopic and histopathological evaluation of BE are not adequate for effective screening of high risk patients. Therefore, molecular abnormalities associated with BE have been considered as surrogate markers and their use as such is proposed. Flow cytometry is the most useful adjunct to histology, and ploidy status of BE is an independent risk factor. Cyclin D1 overexpression is inversely correlated with survival in EA. C-erbB2 (+) patients have poorer prognosis. High plasma adenomatous polyposis coli levels correlate with reduced patient survival. p53 expression allows patient risk for EA stratification. Nuclear factor-kappaB overexpression inversely correlates with good response to adjuvant chemotherapy and radiotherapy in EA. Patients with cyclooxygenase-2 overexpression have reduced survival rates. Increased E-cadherin staining is associated with shorter survival in EA patients who received chemoradiotherapy. Finally, existing data cannot rule out a correlation between EA and colorectal tumors. Seventeen BE molecular alterations yielded noteworthy clinical implications. Apart from endoscopy and histology, these data allow for better risk stratification for patients with BE and for more efficient and timely therapeutic approaches.

Development of Barrett's esophagus six months after total gastrectomy

Barrett's esophagus (BE) is an acquired disease of the esophagus, in which esophageal squamous epithelium is changed by injury from reflux to metaplastic intestinal type columnar epithelium. BE is the premalignant lesion of adenocarcinoma of the esophagus. It is widely accepted that the long-standing reflux of gastric acid is a catalyst for the development of BE. More recent work points toward the reflux of duodenal secretions as a catalyst in this disease process as well. Moreover, the time course for the development of BE once a patient has reflux is not known. Our case challenges the currently defined time course of "long-standing" reflux symptoms for the development of BE, and supports the role of duodenal secretions alone in the development of BE. A 68-yr-old Caucasian man was admitted with weight loss, left upper quadrant pain, a hemoglobin of 6.8, and heme-positive stool. Esophagogastroduodenoscopy (EGD) revealed normal esophageal mucosa and a mass in the gastric cardia. Biopsies showed moderately differentiated gastric adenocarcinoma. The patient underwent a total gastrectomy, distal esophagectomy, and a Roux-en-Y esophagojejunostomy. Pathology confirmed gastric adenocarcinoma (T1 N0 Mx). The distal esophagus and gastroesophageal junction in the resected specimen were grossly and microscopically normal. Six months later an EGD, prompted by new complaints of regurgitation and dyspepsia, revealed distal esophageal mucosa lined by red-colored columnar tissue. Biopsies showed intestinal type epithelium. Thus, our case report's contribution to the current literature is twofold. It provides evidence of development of BE solely from duodenal reflux, and it documents a relatively short time span to development of BE.

Review article: trials on reflux disease -- the role of acid secretion and inhibition

The importance of gastric acid in the pathophysiology of gastro-oesophageal reflux disease is substantiated by the extraordinary therapeutic success of acid inhibition in the management of the disease. The influence of many risk factors for gastro-oesophageal reflux disease is also mediated through their effect on gastric acid secretion and acid reflux. Helicobacter pylori reduces the risk of gastro-oesophageal reflux disease by causing corpus gastritis and reducing gastric acid output. The geographical and temporal trends of H. pylori infection in human populations and its influence on gastric acid secretion are responsible for much of the apparent epidemiology of gastro-oesophageal reflux disease. On average, intra-oesophageal exposure to acid is higher in patients who respond poorly to antisecretory medication. It also tends to increase with increasing severity of reflux disease. However, gastric acid secretion and intra-oesophageal acid exposure vary markedly in reflux patients. The degrees of gastric or intra-oesophageal acidity do not allow the prediction of the presence or severity of gastro-oesophageal reflux disease in the individual subject. The many clinical trials on gastro-oesophageal reflux disease indicate that the reflux of gastric acid constitutes an essential mechanism in the development of this disease, but that additional and partly unknown risk factors must contribute to its aetiology and promote its occurrence in the individual patient.

The prevalence of Helicobacter pylori infection and the status of gastric acid secretion in patients with Barrett's esophagus in Japan

OBJECTIVES

The acidity of the refluxate into the esophagus is a key factor for the pathogenesis of gastroesophageal reflux disease. Helicobacter pylori (H. pylori) infection can influence gastric acid secretion. We have reported that H. pylori infection prevents reflux esophagitis by decreasing gastric acid secretion in Japanese patients, but the role of this organism in Barrett's esophagus is unclear. The aim of this study was to investigate the prevalence of H. pylori infection and gastric acid secretion in Japanese patients with reflux esophagitis with or without Barrett's esophagus.

METHODS

We enrolled 112 reflux esophagitis patients who were examined for the status of H. pylori and acid secretion in this study. They were divided into three groups, according to the presence or absence of Barrett's esophagus as follows: reflux esophagitis group without Barrett's esophagus (reflux esophagitis alone) (80 patients); short-segment Barrett's esophagus group (16 patients); and long-segment Barrett's esophagus group (LSBE) (16 patients). Age- and sex-matched control subjects were also assigned to the 80 patients with reflux esophagitis alone. The prevalence of H. pylori infection was determined by histology, rapid urease tests, and serum IgG antibodies. Gastric acid secretion was evaluated by the endoscopic gastrin test (EGT).

RESULTS

The overall prevalence of H. pylori infection in the reflux esophagitis patient group (24.1%) was significantly lower than the control group (71.2%) (odds ratio 0.13, 95% confidence interval 0.07-0.24; p < 0.0001). The prevalence of H. pylori infection in the patients with Barrett's esophagus tended to be lower than that in the patients with reflux esophagitis alone (reflux esophagitis alone; 30.0%, SSBE; 18.7%, LSBE; 0%), especially in the patients with LSBE compared with the reflux esophagitis alone group (p < 0.01). The EGT value of the respective reflux esophagitis patient group was significantly higher than the control group. The EGT value in the patients with Barrett's esophagus tended to be higher than that in the patients with reflux esophagitis alone, but the difference was not statistically significant. When examined in H. pylori-negative subjects, no difference was found in the EGT value between the control subjects and the patients with reflux esophagitis alone, but it was significantly higher in patients with Barrett's esophagus than the control subjects (p < 0.05). On the other hand, when examined in the H. pylori-positive subjects, the EGT value was significantly higher in the patients with reflux esophagitis alone than in the control subjects (p < 0.01).

CONCLUSIONS

H. pylori infection may play a protective role in the development of Barrett's esophagus, especially in the development of LSBE in Japan. Gastric acid hypersecretion may be concerned with the development of Barrett's esophagus in addition to the absence of H. pylori infection.

Enhanced expression of interleukin-8 and activation of nuclear factor kappa-B in endoscopy-negative gastroesophageal reflux disease

OBJECTIVE

Interleukin-8 (IL-8) mediates neutrophil trafficking via its receptors. Recent studies have shown that IL-8 is likely involved in the development and progression of erosive reflux esophagitis (RE), yet little is known about its implication in endoscopy-negative gastroesophageal reflux disease (GERD). The purpose of this study was to determine IL-8 messenger ribonucleic acid (mRNA) expression levels in endoscopy-negative GERD, along with assessment of nuclear factor kappaB (NF-kappaB) activation, which upregulates IL-8 expression.

METHODS

We studied 31 patients with endoscopy-negative GERD, 15 patients with erosive RE, and 15 asymptomatic controls. Paired biopsy samples were taken from the esophagus 3 cm above the gastroesophageal junction; one biopsy was snap-frozen for measurement of IL-8 mRNA levels by real-time quantitative polymerase chain reaction, and another was formalin-fixed for histopathological evaluation. In nine endoscopy-negative GERD patients, the IL-8 mRNA expression levels were measured before and 8 wk after treatment with lansoprazole. We also sampled additional specimens for NF-kappaB-DNA binding assay and immunohistochemical analyses of NF-kappaB p65 and p50 subunits, IL-8 and specific IL-8 receptor, CXCR-1.

RESULTS

The relative IL-8 mRNA expression levels were significantly higher in esophageal mucosa of patients with endoscopy-negative GERD than those of the controls. The presence of basal zone hyperplasia and intraepithelial neutrophils, histopathological hallmarks of GERD, were associated with higher levels of IL-8 mRNA. Lansoprazole treatment significantly reduced the IL-8 mRNA expression levels. The esophageal epithelium of patients with GERD showed intense immunoreactivity for IL-8, and expressed CXCR-1 antigen. We found NF-kappaB activation in esophageal mucosa in GERD patients and the NF-kappaB subunits were localized predominantly in the nuclei of IL-8-expressing cells.

CONCLUSIONS

Our results demonstrate enhanced mucosal expression of IL-8 in incipient GERD even without mucosal breaks. NF-kappaB activation may be implicated in the pathogenesis in GERD.

Risk factors for esophagitis in extreme acid hypersecretors with and without Zollinger-Ellison syndrome

BACKGROUND & AIMS

Whereas severe duodenal ulcer is the hallmark of acid hypersecretion in Zollinger-Ellison syndrome (ZE) and similar states, the esophagus also is at high risk. We quantified the incidence of esophagitis and various risk factors that might contribute to it.

METHODS

Sixty-eight acid hypersecretors (basal acid output >15 mmol/h), 50 patients with ZE, and 18 patients without ZE with normal gastrin levels were studied by gastric analysis, serum gastrin levels, and endoscopy. In 44 of 68 patients, esophageal manometry was performed after the esophagus had healed.

RESULTS

Erosive esophagitis, grade 2 or worse, was found in 65%; an additional 15% had heartburn only, for a total reflux disease incidence of 80%. ZE accounted for 95% of severe esophagitis. Patients with and without esophagitis had the same high overnight fasting gastric residual volume and acidity, as well as basal and peak acid and pepsin outputs. However, patients with esophagitis had a lower median lower esophageal sphincter pressure (LESP) of 15.5 vs. 23 mm Hg in those without symptoms; the critical discriminator threshold was 16 mm Hg. Multivariate analysis further identified frequent vomiting and obesity as positive predictors of esophagitis, whereas Helicobacter pylori was a strong negative predictor (odds ratio, 0.16), possibly related to an elevated LESP in patients infected with H. pylori.

CONCLUSIONS

Erosive esophagitis is very common in acid hypersecretors. Identified risk factors that could promote abnormal esophageal exposure to the high acid and pepsin levels in our population of hypersecretors were vomiting, LESP < 16 mm Hg, and obesity, whereas H. pylori appeared to protect the esophagus not by reduced acid, but through an elevated LESP.

Barrett's oesophagus: optimal strategies for prevention and treatment

Barrett's oesophagus is a change in the lining of the distal oesophagus recognised at endoscopy and documented to have intestinal metaplasia by biopsy. It is thought that it is an acquired condition resulting from chronic gastro-oesophageal reflux disease (GORD). Barrett's oesophagus has the potential to progress to adenocarcinoma of the oesophagus. Evidence to support the association between Barrett's oesophagus and GORD appears to be strong but circumstantial. The intermediate steps that lead from GORD to Barrett's oesophagus are speculative and the timeline for the development of this condition remains obscure. It has yet to be demonstrated that erosive oesophagitis is a necessary intermediate step for the development of Barrett's oesophagus. In spite of effective therapy, documentation that medical or surgical therapy prevents Barrett's oesophagus is lacking. The goal of screening for Barrett's oesophagus is ultimately to improve the survival of patients with adenocarcinoma of the oesophagus. This goal has not been achieved and the evidence-based criteria for screening remain to be defined. Medical and surgical therapy of Barrett's oesophagus is effective in controlling reflux, although not proven to prevent neoplastic progression of the at risk mucosa. Endoscopic techniques of mucosal injury have been applied as alternatives to oesophagectomy in efforts to prevent progression to cancer. Surveillance endoscopy and biopsy is the currently accepted method aimed at early intervention and improved survival for oesophageal adenocarcinoma. A working surveillance protocol to accomplish this is proposed based on dysplasia grade. If no dysplasia is found and confirmed with subsequent endoscopy and biopsy, a 3-year interval is recommended. If only low grade dysplasia is confirmed, then annual endoscopy until no dysplasia is recognised is recommended. On the basis of defined risk factors, high grade dysplasia can lead to intense surveillance every 3 months or an intervention. Future developments in understanding the biology of Barrett's oesophagus and in therapeutic interventions will provide an opportunity for more effective screening, surveillance and prevention of neoplastic progression.

Meal-stimulated gastric acid secretion and integrated gastric acidity in gastro-oesophageal reflux disease

BACKGROUND

No current methods exist to determine meal-stimulated gastric acid secretion in humans under conditions that approximate those of daily living with the ingestion of breakfast, lunch and dinner.

METHODS

Gastric and oesophageal pH were measured in 26 healthy subjects and in 59 subjects with gastro-oesophageal reflux disease. Meal-stimulated gastric acid secretion was calculated from the buffer capacity of the meals determined in vitro and from the time required for the gastric pH to decrease to pH 2 in vivo following ingestion of the meal.

RESULTS

There was a significant correlation between gastric secretion with each meal and the corresponding post-prandial integrated gastric acidity. There was also a significant correlation between meal-stimulated gastric secretion and integrated gastric acidity from 09.00 to 22.00 h in both subjects with gastro-oesophageal reflux disease and controls. In subjects with gastro-oesophageal reflux disease, gastric secretion and integrated gastric acidity from 09.00 to 22.00 h were significantly higher than those in controls. There was a significant correlation between oesophageal acidity and integrated gastric acidity from 09.00 to 22.00 h in subjects with gastro-oesophageal reflux disease.

CONCLUSIONS

As post-prandial gastric acidity is increased in subjects with gastro-oesophageal reflux disease, it seems likely that increased gastric acidity is an important aetiological factor in this disease.

Elevated levels of chemokines in esophageal mucosa of patients with reflux esophagitis

OBJECTIVE

Chemokines play a key role in the pathogenesis of various inflammatory conditions. However, there is little information on their profile in reflux esophagitis (RE). We sought to study esophageal mucosa levels of chemokines in RE.

METHODS

A total of 32 outpatients with RE and 13 normal controls were studied. Endoscopic severity of RE was classified according to the Los Angeles grading system. Paired biopsy specimens were taken from the esophagus 3 cm above the gastroesophageal junction; one biopsy was snap frozen for measurement of mucosal levels of interleukin 8 (IL-8), monocyte chemoattractant protein 1 (MCP-1), regulated on activation normal T-cell expressed and presumably secreted (RANTES), and IL-1 beta by enzyme linked immunosorbent assays, while the other was formalin-fixed for histopathological evaluation.

RESULTS

IL-8, MCP-1, and RANTES levels were significantly higher in esophageal mucosa of RE patients than those of the controls. IL-8 levels correlated significantly with the endoscopic severity of RE. Basal zone hyperplasia and papillary elongation, histopathological hallmarks of RE, were both associated with higher levels of IL-8 and MCP-1. The presence of intraepithelial neutrophils and eosinophils, which also indicate RE, was associated with high levels of IL-8 and RANTES, respectively. There were no significant differences in IL-1 beta levels between the RE and control groups, but IL-1 beta levels correlated significantly with the IL-8 production. Again, the IL-8 levels were significantly decreased after lansoprazole treatment.

CONCLUSION

Our results indicate that chemokines produced locally in the esophageal mucosa may be involved in the development and progression of RE.

Cisapride inhibits meal-stimulated gastric acid secretion and post-prandial gastric acidity in subjects with gastro-oesophageal reflux disease

BACKGROUND AND AIMS

KCNQ1 potassium channels in human gastric parietal cells are thought to be involved in gastric acid secretion. As cisapride can inhibit similar channels in other tissues and is an effective treatment for nocturnal heartburn, we examined the effects of cisapride on gastric and oesophageal acidity, gastric emptying and heartburn severity in subjects with gastro-oesophageal reflux disease.

METHODS

Subjects (n = 11) had suffered from heartburn four times or more per week for at least 6 months. Gastric pH and oesophageal pH were measured before, during and after a standard meal ingested over 15 min. Each subject received placebo or 10 mg cisapride orally, 30 min before the beginning of the meal. Meal-stimulated gastric acid secretion was calculated from the amount of HCl required to titrate the homogenized standard meal to pH 2 in vitro and the time required for the pH of the ingested meal to decrease to pH 2 in vivo. Heartburn severity was assessed at 15-min intervals beginning at the end of the meal. Gastric emptying of solids was measured using a [(13)C]-octanoic acid breath test.

RESULTS

Cisapride significantly decreased meal-stimulated gastric acid secretion by 20%, decreased integrated gastric and oesophageal acidity by 50-60% and transiently increased the expiration of (13)CO(2). Cisapride did not significantly alter heartburn severity.

CONCLUSIONS

The cisapride-induced decreases in meal-stimulated gastric acid secretion, gastric acidity and oesophageal acidity in subjects with gastro-oesophageal reflux disease can account for its beneficial clinical effects. These results also raise the possibility that gastric KCNQ1 potassium channels are important in meal-stimulated gastric acid secretion and possibly in the pathophysiology of gastro-oesophageal reflux disease.

Review article: gastro-oesophageal reflux disease--pathophysiological issues of clinical relevance

Gastro-oesophageal reflux disease is a multifactorial disorder in which the pathophysiological mechanisms are variably combined in different patients. Motor dysfunction of the lower oesophageal sphincter (LOS) and, possibly, the proximal stomach is a major cause of the increase in the number of reflux episodes. Transient LOS relaxation is the main mechanism of reflux in many patients with endoscopically negative disease, whereas a hypotensive LOS becomes relevant only in patients with oesophagitis. Alterations in primary and secondary peristalsis contribute to the increased oesophageal acid exposure by delaying clearance. The presence of a hiatus hernia, especially when voluminous and/or non-reducible, increases the number of reflux episodes by mechanically weakening the oesophago-gastric junction, and impairs oesophageal clearance. Hypersensitivity to acid is often present and contributes to the clinical manifestations of the disease, whereas oesophageal hypersensitivity, both to chemical and mechanical stimuli, plays a predominant role in a subset of patients. Increased concentrations of noxious compounds in the oesophageal refluxate may contribute to the development of anatomical lesions, but this is still a matter for debate. The clinical relevance of Helicobacter pylori infection and of mucosal defensive factors still needs to be fully elucidated.

Barrett's esophagus

Barrett's esophagus is an acquired condition resulting from severe esophageal mucosal injury. It still remains unclear why some patients with gastroesophageal reflux disease develop Barrett's esophagus whereas others do not. The diagnosis of Barrett's esophagus is established if the squamocolumnar junction is displaced proximal to the gastroesophageal junction and if intestinal metaplasia is detected by biopsy. Despite this seemingly simple definition, diagnostic inconsistencies remain a problem, especially in distinguishing short segment Barrett's esophagus from intestinal metaplasia of the gastric cardia. Barrett's esophagus would be of little importance were it not for its well-recognized association with adenocarcinoma of the esophagus. The incidence of esophageal adenocarcinoma continues to increase and the 5-year survival rate for this cancer remains dismal. However, cancer risk for a given patient with Barrett's esophagus is lower than previously estimated. Current strategies for improved survival in patients with esophageal adenocarcinoma focus on cancer detection at an early and potentially curable stage. This can be accomplished either by screening more patients for Barrett's esophagus or with endoscopic surveillance of patients with known Barrett's esophagus. Current screening and surveillance strategies are inherently expensive and inefficient. New techniques to improve the efficiency of cancer surveillance are evolving rapidly and hold the promise to change clinical practice in the future. Treatment options include aggressive acid suppression, antireflux surgery, chemoprevention, and ablation therapy, but there is still no clear consensus on the optimal treatment for these patients.

Synergy between low-dose ranitidine and antacid in decreasing gastric and oesophageal acidity and relieving meal-induced heartburn

BACKGROUND

The pathophysiology of recurrent postprandial heartburn and the basis for the effectiveness of antacids or low doses of histamine H2-receptor antagonists have not been well studied.

METHODS

The selected subjects (n=26) had heartburn more than four times a week for at least 2 months, which was responsive to antacids. Gastric pH and oesophageal pH were measured for 1 h before, during, and 4.5 h after ingestion of a meal over 0.5 h. Heartburn severity was assessed at 15-min intervals beginning at the end of the meal. Each subject randomly received placebo, 75 mg ranitidine, 420 mg calcium carbonate, and ranitidine plus calcium carbonate. Values for pH were converted to acid concentration (mM) and integrated acidity was calculated from the cumulative, time-weighted means of the acid concentrations for every second of the postprandial recording period.

RESULTS

There was a close temporal relationship between heartburn and oesophageal acidity. Most oesophageal acid exposure occurred over a 90-min period that began approximately 45 min after the end of the meal. During this period the gastric acid concentration was less than 5% of maximal. Ranitidine significantly decreased gastric but not oesophageal acidity, whilst antacid significantly decreased oesophageal but not gastric acidity. Ranitidine plus antacid significantly decreased both gastric and oesophageal acidity. Antacid alone and ranitidine plus antacid significantly decreased heartburn severity.

CONCLUSIONS

Determining integrated gastric and oesophageal acidity provides novel information regarding the pathophysiology of meal-induced heartburn as well as the actions of low-dose ranitidine and antacid. For subjects with meal-induced heartburn, treatment with low-dose ranitidine plus antacid is particularly effective in decreasing gastric and oesophageal acidity as well as heartburn severity.

Integrated acidity and the pathophysiology of gastroesophageal reflux disease

OBJECTIVES

The aim of this study was to demonstrate that integrated esophageal and gastric acidity values, calculated from 24-h pH recordings, can provide more precise quantitative temporal data than the conventional pH parameters historically associated with gastroesophageal reflux disease (GERD) investigations.

METHODS

Esophagogastroduodenoscopy results and pH tracings from 20 GERD subjects with > or =10% esophageal acid contact time were studied. Integrated gastric and esophageal acidity were calculated from time-weighted average hydrogen ion concentrations at each second of the 24-h recording period.

RESULTS

Integrated esophageal acidity correlated with grade of esophagitis. Two quite distinct GERD subtypes were identified, with either a monophasic or biphasic pattern of integrated esophageal acidity. "Biphasic" subjects differed from "monophasic" subjects in terms of magnitude and pattern of integrated esophageal acidity. Although both groups had significant integrated nocturnal gastric acidity, only the biphasic GERD subjects had concomitant increases in nocturnal integrated esophageal acidity. Esophagitis grade was correlated with magnitude rather than pattern of integrated esophageal acidity, and it was possible to calculate a reflux coefficient that seems to provide an estimate of the quantitative motor disturbance present in GERD.

CONCLUSIONS

Integrated esophageal and gastric acidity provide quantitative measures of GERD pathophysiology and, compared to conventional pH parameters, should enhance evaluation of therapeutic interventions.

Pathogenesis of gastroesophageal reflux and Barrett esophagus

Barrett esophagus is a metaplastic condition that affects the lower esophagus and is a complication of gastroesophageal reflux disease (GERD). Under normal circumstances, the reflux of gastric contents into the esophagus is prevented by a complex barrier at the esophagogastric junction. Dysfunction of the lower esophageal sphincter and the presence of a hiatal hernia lead to failure of this barrier. Esophageal mucosal damage results from the chronic exposure of the esophageal mucosa to gastroduodenal contents and the lack of an effective mucosal defense. This article is an overview of the dysfunction of the esophagogastric junction that leads to GERD. The role of the contents of the reflux and that of Helicobacter pylori infection in the pathogenesis of Barrett esophagus are also summarized.

Pathogenesis of gastroesophageal reflux and Barrett esophagus

Barrett esophagus is a metaplastic condition that affects the lower esophagus and is a complication of gastroesophageal reflux disease (GERD). Under normal circumstances, the reflux of gastric contents into the esophagus is prevented by a complex barrier at the esophagogastric junction. Dysfunction of the lower esophageal sphincter and the presence of a hiatal hernia lead to failure of this barrier. Esophageal mucosal damage results from the chronic exposure of the esophageal mucosa to gastroduodenal contents and the lack of an effective mucosal defense. This article is an overview of the dysfunction of the esophagogastric junction that leads to GERD. The role of the contents of the reflux and that of Helicobacter pylori infection in the pathogenesis of Barrett esophagus are also summarized.

Barrett's oesophagus: diagnosis and management

Gastro-oesophageal reflux disease and its sequela, Barrett's oesophagus, are the major recognized risk factors for oesophageal adenocarcinoma, a tumour whose frequency has increased dramatically in Western countries over the past few decades. Barrett's oesophagus develops through the process of metaplasia in which one adult cell type replaces another. The metaplastic, intestinal-type cells of Barrett's oesophagus are predisposed to develop genetic changes that eventuate in cancer. This report reviews the recent controversy regarding diagnostic criteria for Barrett's oesophagus, and provides practical guidelines for identifying the condition. The risks and benefits of the proposed medical, surgical and endoscopic therapies for Barrett's oesophagus are discussed in detail, and the approach to management recently endorsed by the American College of Gastroenterology is summarized.

Failure of oesophageal acid control in candidates for Barrett's oesophagus reversal on a very high dose of proton pump inhibitor

BACKGROUND

Normalization of oesophageal acid exposure using high dose proton pump inhibitors in patients who are candidates for ablation therapy has been suggested to be essential for successful Barrett's reversal. However, the success rate for achieving pH normalization has not been determined.

METHODS

Patients with Barrett's oesophagus (2-6 cm in length) who were found to be eligible for ablation therapy using multipolar electrocoagulation were included in this prospective study. Patients underwent an upper endoscopy to determine Barrett's length and other anatomic characteristics. Biopsies were obtained to rule out dysplasia. Subsequently, patients were treated with omeprazole 40 mg b.d. Twenty-four hour oesophageal pH monitoring was performed after a mean period of 8.4 +/- 0.6 days of therapy.

RESULTS

Twenty-five patients were enrolled into the study. The pH test was abnormal in four (16%) of the study subjects. An additional two (8%) patients had abnormal supine percentage time with pH less than 4. There was no significant difference in oesophageal acid control between patients with long vs. short segment Barrett's oesophagus. Elderly (> 60 years) patients tended to have less acid control than younger (</= 60 years) patients.

CONCLUSIONS

Failure of oesophageal acid control in candidates for Barrett's oesophagus reversal on very high dose of proton pump inhibitor is not uncommon. Our study suggests that ambulatory 24-h oesophageal pH monitoring should be considered in all candidates for Barrett's reversal who are treated with high dose proton pump inhibitor to ensure normalization of oesophageal acid exposure.

Association of obesity with hiatal hernia and esophagitis

OBJECTIVE

Although weight loss is commonly recommended for symptoms of gastroesophageal reflux, a relationship between excessive body weight and esophageal reflux has not been established. The aim of this study was to determine whether obesity is associated with the presence of a hiatal hernia (HH) and/or an endoscopic diagnosis of esophagitis.

METHODS

Retrospective case control studies were done using 1389 patients who underwent gastric analysis and upper GI endoscopy between 1974 and 1995. After excluding patients with Zollinger-Ellison syndrome, 189 cases of esophagitis with 1024 controls were identified. In a separate analysis of the database, 151 cases of HH with 1053 controls were also identified. Patients were classified by body mass index (BMI) as: thin (BMI <20 kg/m2), normal (BMI 20-25), mildly obese (BMI 25-30), and obese (BMI >30).

RESULTS

Excessive body weight was significantly associated with the presence of HH, the probability of HH increasing with each level of BMI (p < 0.01), as well as with esophagitis (OR 1.8; 95% CI 1.4-2.1). HH was independently associated with esophagitis (OR 4.2 95% CI 2.9-6.1); when controlled for the effect of HH, the association between BMI and esophagitis diminished but remained significant. In the population as a whole, for the presence of esophagitis multiple logistic regression indicates BMI and hiatal hernia were significant factors but gender and race did not appear to be.

CONCLUSIONS

Excessive body weight is a significant independent risk factor for hiatal hernia and is significantly associated with esophagitis, largely through an increased incidence of hiatal hernia. Whites are more likely to have the combination of esophagitis and hiatal hernia than are blacks.

Cisapride 20 mg b.i.d. provides symptomatic relief of heartburn and related symptoms of chronic mild to moderate gastroesophageal reflux disease. CIS-USA-52 Investigator Group

OBJECTIVE

We evaluated the efficacy and safety of a twice-daily dosage regimen of cisapride 20 mg in relieving the symptoms of mild-moderate gastroesophageal reflux disease (GERD) in patients with moderate intensity heartburn and no history of erosive esophagitis.

METHODS

After a 2-wk, single-blind, placebo run-in period, 398 patients who continued to experience moderate intensity heartburn were randomized to either placebo (n = 196) or cisapride 20 mg (n = 202) twice daily for 4 wk.

RESULTS

Compared with placebo, cisapride significantly reduced scores for daytime and nighttime heartburn (p < 0.001), total regurgitation (p < 0.001), eructation (p = 0.04), and early satiety (p = 0.04). Cisapride 20 mg b.i.d. was also superior to placebo in reducing total use of rescue antacid medication (p < 0.001); reducing, in concordance analyses, daytime and nighttime heartburn with antacid usage (p < 0.001); increasing the percentage of heartburn-free days and antacid-free nights (p < 0.5); and increasing the percentage of patients self-rated as having minimal or better symptomatic improvement (p = 0.01). Cisapride 20 mg b.i.d. was well tolerated. The most common adverse event in the cisapride group was diarrhea, reported by 10% of patients, compared with an incidence of 4% in the placebo group.

CONCLUSION

Cisapride 20 mg b.i.d. was shown to be effective and safe for the short-term treatment of daytime and nighttime heartburn and for other symptoms associated with mild-moderate GERD.

Barrett's esophagus

The columnar replacement of squamous epithelium in the lower esophagus is the result of gastroesophageal reflux. Whether the squamous cells are replaced or undergo metaplasia is still conjectural. This neoepithelium is unstable in the presence of continued reflux and prone to complications of stricture, ulceration, and adenocarcinoma. Considerable evidence supports the hypothesis that duodenal contents play a role in the development of Barrett's esophagus and its complications. The increasing incidence of adenocarcinoma in Barrett's esophagus is of concern in the Western World. Surveillance programs in some centers have been successful in early diagnosis, and excellent survival periods have been reported following resection in these cases. Both medical and surgical antireflux treatment is successful in symptom relief, but even in the absence of symptoms, reflux may continue. Surgery offers better overall results than proton pump inhibition of gastric acid and has been more popular since less aggressive (minimally invasive) techniques have been popularized. Mucosal ablation and antireflux measures by medicine or surgery are still in the experimental stages but hold considerable promise for the future.

Gastroesophageal reflux disease in patients with columnar-lined esophagus

Columnar-lined esophagus or Barrett's esophagus is closely associated with gastroesophageal reflux disease. Animal and human studies have shown not only acid but duodenogastroesophageal reflux acting in synergy with acid causes the most esophageal injury. Patients with Barrett's esophagus manifest typical and atypical symptoms of reflux. Ten percent to 25%, however, have clinically silent reflux. Early diagnosis is essential for this disease as it is a risk factor for the development of adenocarcinoma of the esophagus.

Prostaglandin E2 is the major arachidonic acid metabolite secreted by esophageal mucosal cells in rabbits

Unlike gastric mucosa, it has been considered that lipoxygenase metabolites protect the esophageal mucosa and that prostaglandins are only secreted in the presence of esophageal inflammation. The aim of this study was to determine the profile of arachidonic acid metabolites and their response to regulatory compounds in rabbit esophageal mucosal cells in culture. Eicosanoids secreted into the medium were extracted and identified by HPLC and RIA. Esophageal mucosal cells in culture metabolized arachidonic acid mainly through the cycloxygenase pathway and PGE2 was the major arachidonic acid metabolite secreted. The addition of IL-1 beta and A23187 (calcium ionophore) stimulated PGE2 synthesis. In basal conditions neither leukotrienes nor HETEs were detected. However, the addition of the NDGA induced the secretion of lipoxygenase metabolites identified as 12-15 HETEs. In conclusion, rabbit esophageal epithelial cells in culture metabolize arachidonic acid via both cycloxygenase and lipoxygenase pathways. In our system, PGE2 was the main arachidonic acid metabolite.

Gastric secretion of acid and pepsin in patients with esophageal stricture and appropriate controls

Most cases of esophageal stricture are associated with acid/peptic reflux esophagitis. While patients with strictures commonly have disordered lower esophageal sphincters and poor clearance and neutralization mechanisms, it is not known whether they also have abnormal gastric secretion. This study examined fasting, basal, and stimulated acid and pepsin secretion. With an endoscopic diagnosis of esophagitis, patients with stricture (< 12.5 mm) were matched for age, sex, concurrent gastrointestinal disease (duodenal ulcer, N = 9), Zollinger-Ellison syndrome (N = 6), and postgastric surgery state (N = 5), as well as the absence of ulcer disease (non-DU, N = 37). Fasting, basal, and pentagastrin-stimulated acid and pepsin secretion were measured. Overall, the 57 stricture patients had the same acid and pepsin secretion as their matched controls with esophagitis; the same was true for each of the subgroups (ZES, DU, non-DU, and postsurgical). Stricture patients weighed less and had a lower body mass index (P < 0.01). Patients with esophageal peptic stricture have the same acid and pepsin output as control patients matched for sex, age, background gastrointestinal disease, and the presence of esophagitis.