Increased acid and bile reflux in Barrett's esophagus compared to reflux esophagitis, and effect of proton pump inhibitor therapy

Role of bile acids and their receptors in gastrointestinal and hepatic pathophysiology

Bile acids (BAs) can regulate their own metabolism and transport as well as other key aspects of metabolic homeostasis via dedicated (nuclear and G protein-coupled) receptors. Disrupted BA transport and homeostasis results in the development of cholestatic disorders and contributes to a wide range of liver diseases, including nonalcoholic fatty liver disease and hepatocellular and cholangiocellular carcinoma. Furthermore, impaired BA homeostasis can also affect the intestine, contributing to the pathogenesis of irritable bowel syndrome, inflammatory bowel disease, and colorectal and oesophageal cancer. Here, we provide a summary of the role of BAs and their disrupted homeostasis in the development of gastrointestinal and hepatic disorders and present novel insights on how targeting BA pathways might contribute to novel treatment strategies for these disorders.

Systematic review: duodenogastroesophageal (biliary) reflux prevalence, symptoms, oesophageal lesions and treatment

BACKGROUND

The prevalence of duodenogastroesophageal reflux (DGER) and its effect on symptoms and oesophageal lesions in gastroesophageal reflux disease (GERD) is unclear.

AIMS

To conduct a systematic review to determine the prevalence of DGER among patients with GERD, the effect of DGER on symptoms and oesophageal lesions, and the treatment of DGER.

METHODS

We searched Pubmed and MEDLINE for full text, English language articles until October 2020 that evaluated DGER prevalence among patients with GERD, the effect of DGER on symptoms and oesophageal lesions, and the treatment of DGER.

RESULTS

We identified 3891 reports and included 35 which analysed DGER prevalence in GERD, 15 which evaluated its effect in non-erosive reflux disease (NERD), 17 on erosive oesophagitis, 23 in Barrett's, and 13 which evaluated the treatment of DGER. The prevalence of DGER, when evaluated by Bilitec, among all GERD patients ranged from 10% to 97%, in NERD 10%-63%, in erosive oesophagitis 22%-80% and in Barrett's 50%-100%. There were no differences in the presence or degree of DGER among patients who were asymptomatic or symptomatic on proton pump inhibitors (PPI). The most commonly evaluated treatments for DGER were PPIs and DGER reduced post-PPI therapy in all studies.

CONCLUSIONS

The prevalence of DGER increased with more advanced oesophageal lesions and did not explain persisting symptoms among patients taking PPI therapy. PPIs appear to be effective in the treatment of DGER. DGER remains an important consideration in patients with GERD and future therapies deserve more study.

Intestinal metaplasia around the gastroesophageal junction is frequently associated with antral reactive gastropathy: implications for carcinoma at the gastroesophageal junction

Increasing evidence suggests that bile reflux (BR) plays a major role in mucosal injury, leading to adenocarcinoma of the proximal stomach and distal esophagus. However, gastric BR is difficult to diagnose and investigate. Reactive gastropathy (RG), in the absence of nonsteroidal anti-inflammatory drugs (NSAIDs) and other known causes, likely represents bile-mediated injury to the gastric mucosa. The goal of this study is to explore the association between antral RG and gastroesophageal junction (GEJ) mucosal inflammation and intestinal metaplasia (IM). The pathology database was searched for patients who had gastric biopsies with a diagnosis of antral RG and concurrent gastric cardia/GEJ/distal esophagus biopsies from 2013 to 2015. Age- and sex-matched patients with normal gastric antral biopsies served as controls. Biopsies from the GEJ region were evaluated for histological changes, including inflammation, antral and pancreatic metaplasia, RG, the type of gastric glands, proton pump inhibitor (PPI) changes, and IM. Detailed clinical history and medication use (including PPIs and NSAIDs) were recorded. IM in the GEJ region was more frequent in patients with antral RG than in controls (33.0% vs. 5.2%, 95% confidence interval [18.3-37.3%]). In addition, inflammation, other mucosal changes around the GEJ (RG and foveolar hyperplasia), antral IM, and PPI-associated mucosal changes were also more frequently seen in patients with antral RG. Our results show that antral RG is associated with mucosal injury and IM around GEJ, suggesting a role of BR. Further studies are needed to study duodenogastric-esophageal BR and its role in development of proximal gastric and distal esophageal adenocarcinoma.

Esophageal Function Abnormalities in Patients With Barrett's Esophagus

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

Interaction of epidermal growth factor with COX-2 products and peroxisome proliferator-activated receptor-γ system in experimental rat Barrett's esophagus

Mixed acidic-alkaline refluxate is a major pathogenic factor in chronic esophagitis progressing to Barrett's esophagus (BE). We hypothesized that epidermal growth factor (EGF) can interact with COX-2 and peroxisome proliferator-activated receptor-γ (PPARγ) in rats surgically prepared with esophagogastroduodenal anastomosis (EGDA) with healthy or removed salivary glands to deplete salivary EGF. EGDA rats were treated with 1) vehicle, 2) EGF or PPARγ agonist pioglitazone with or without EGFR kinase inhibitor tyrphostin A46, EGF or PPARγ antagonist GW9662 respectively, 3) ranitidine or pantoprazole, and 4) the selective COX-2 inhibitor celecoxib combined with pioglitazone. At 3 mo, the esophageal damage and the esophageal blood flow (EBF) were determined, the mucosal expression of EGF, EGFR, COX-2, TNFα, and PPARγ mRNA and phospho-EGFR/EGFR protein was analyzed. All EGDA rats developed chronic esophagitis, esophageal ulcerations, and intestinal metaplasia followed by a fall in the EBF, an increase in the plasma of IL-1β, TNFα, and mucosal PGE₂ content, the overexpression of COX-2-, and EGF-EGFR mRNAs, and proteins, and these effects were aggravated by EGF and attenuated by pioglitazone. The rise in EGF and COX-2 mRNA was inhibited by pioglitazone but reversed by pioglitazone cotreated with GW9662. We conclude that 1) EGF can interact with PG/COX-2 and the PPARγ system in the mechanism of chronic esophagitis; 2) the deleterious effect of EGF involves an impairment of EBF and the overexpression of COX-2 and EGFR, and 3) agonists of PPARγ and inhibitors of EGFR may be useful in the treatment of chronic esophagitis progressing to BE.NEW & NOTEWORTHY Rats with EGDA exhibited chronic esophagitis accompanied by a fall in EBF and an increase in mucosal expression of mRNAs for EGF, COX-2, and TNFα, and these effects were exacerbated by exogenous EGF and reduced by removal of a major source of endogenous EGF with salivectomy or concurrent treatment with tyrphostin A46 or pioglitazone combined with EGF. Beneficial effects of salivectomy in an experimental model of BE were counteracted by PPARγ antagonist, whereas selective COX-2 inhibitor celecoxib synergistically with pioglitazone reduced severity of esophageal damage and protected esophageal mucosa from reflux. We propose the cross talk among EGF/EGFR, PG/COX-2, and proinflammatory cytokines with PPARγ pathway in the mechanism of pathogenesis of chronic esophagitis progressing to BE and EAC.

Risk of Esophageal Adenocarcinoma After Antireflux Surgery in Patients With Gastroesophageal Reflux Disease in the Nordic Countries

Importance

Gastroesophageal reflux disease (GERD) is associated with a strong and severity-dependent increased risk of esophageal adenocarcinoma. Whether antireflux surgery prevents esophageal adenocarcinoma is a matter of uncertainty.

Objectives

To examine whether antireflux surgery is associated with reduced risk of esophageal adenocarcinoma and whether the risk is different between surgically and medically treated patients.

Design, Setting, and Participants

In this multinational, population-based retrospective cohort study from Denmark, Finland, Iceland, Norway, and Sweden, patients undergoing surgery were followed up for a median of 12.7 years, and a comparison group of patients receiving medication only were followed up for a median of 4.8 years. All patients with a registered diagnosis of GERD (or an associated disorder), including 48 414 individuals undergoing surgery and 894 492 receiving medication only, were included in the study. The study periods varied in the different countries depending on the year of initiation of registration and the date of data retrieval, from January 1, 1964, to December 21, 2014.

Exposures

Antireflux surgery for GERD.

Main Outcomes and Measures

The risk of esophageal adenocarcinoma over time after surgery was compared with that in a corresponding background population using standardized incidence ratios (SIRs) with 95% CIs and with patients with GERD who received medication using multivariable Cox proportional hazards regression, providing hazard ratios (HRs) with 95% CIs adjusted for confounders.

Results

In this study of 942 906 patients with GERD, 48 414 underwent antireflux surgery (median [interquartile range] age, 66.0 [58.0-73.0] years; 27 161 male [56.1%]) and 894 492 received medication only (median [interquartile range] age, 71.0 [62.0-78.0] years; 434 035 male [48.6%]). Among patients undergoing surgery, 177 developed esophageal adenocarcinoma. Esophageal adenocarcinoma risk decreased in a time-dependent manner after surgery compared with the background population (5 to <10 years after surgery: SIR, 7.63; 95% CI, 5.42-10.43; ≥15 years after surgery: SIR, 1.34; 95% CI, 0.98-1.80). Among patients with more severe and objectively determined GERD, the SIRs were 10.08 (95% CI, 6.98-14.09) at 5 to less than 10 years after surgery and 1.67 (95% CI, 1.15-2.35) at 15 years or more after surgery. The risk of esophageal adenocarcinoma did not change over time in surgical patients compared with patients who received medication only (5 to <10 years after surgery: HR, 2.02; 95% CI, 1.44-2.84; ≥15 years: HR, 1.80; 95% CI, 1.28-2.54). The risk remained stable over time in analyses restricted to severe reflux disease (5 to <10 years after surgery: HR, 1.81; 95% CI, 1.24-2.63; ≥15 years after surgery: HR, 1.69; 95% CI, 1.14-2.51).

Conclusions and Relevance

Medical and surgical treatment of GERD were associated with a similar reduced esophageal adenocarcinoma risk, with the risk decreasing to the same level as that in the background population over time, supporting the hypothesis that effective treatment of GERD might prevent esophageal adenocarcinoma.

Role of Kruppel-Like Factor 5 in Deoxycholic Acid-Mediated Intestinal Transdifferentiation of Esophageal Squamous Epithelium

Barrett's esophagus (BE) is an acquired condition in which normal squamous epithelium is replaced with metaplastic columnar epithelium as a consequence of gastroesophageal reflux disease. BE is known as a precursor of esophageal adenocarcinoma. Currently, the molecular mechanism underlying epithelial metaplasia in BE patients remains unknown. Therefore, we investigated the role of Krüppel-like factor 5 (KLF5) signaling in the initiation of BE-associated metaplasia. Sprague-Dawley (SD) rats were used to create a surgical model of bile reflux injury. Immunohistochemistry was performed to analyze human and mouse esophageal specimens. Human esophageal squamous epithelial (HET-1A) cells were treated with bile acid and used in transfection experiments. Quantitative real-time PCR and western blot analysis were performed to detect the expression of KLF5, CDX2, MUC2 and villin. Epithelial tissue from both the rat BE model and human BE patients strongly expressed KLF5, CDX2, MUC2, and villin. Bile acid treatment also increased the expression of KLF5, CDX2, MUC2 and villin in esophageal epithelial cells in a time-dependent manner. Moreover, siRNA-mediated knockdown of KLF5 blocked the expression of CDX2, MUC2 and villin, but transfection of a KLF5 expression vector into esophageal epithelial cells promoted their transdifferentiation into columnar-like cells, as demonstrated by increased expression of the intestinal markers CDX2, MUC2 and villin. Thus, in addition to its function as a transcription factor, KLF5 may be linked to an increased risk of BE development.

The Role of Acid Suppression in Barrett's Esophagus

In recent years, proton pump inhibitors (PPIs) have come under great scrutiny due to possible adverse, long-term side effects. At the same time, Barrett's esophagus, a premalignant condition in the esophagus, continues to be a disease whose course is thought to be improved by the use of PPIs. We review the impact of proton pump therapy on the esophagus and on Barrett's mucosa. In analyzing changes on a cellular level, we explore the effect of mixed gastric refluxate and the complex cascade that ensues with esophageal exposure of these contents. Because the incidence of esophageal adenocarcinoma is on the rise, we explore other factors that may contribute to the progression of Barrett's from non-dysplastic mucosa to esophageal adenocarcinoma. By revisiting the need for adequate acid suppression in Barrett's and increasing our understanding of other possible factors that may have an effect of Barrett's progression, we hope to support our multifaceted approach to acid suppression in patients with Barrett's esophagus.

Gastroesophageal Mucosal Injury after Cholecystectomy: An Indication for Surveillance?

BACKGROUND

Cholecystectomy alters bile release dynamics from pulsatile meal-stimulated to continuous, and results in retrograde duodeno-gastric bile reflux (DGR). Bile is implicated in mucosal injury after gastric surgery, but whether cholecystectomy causes esophagogastric mucosal inflammation, therefore increasing the risk of metaplasia, is unclear.

STUDY DESIGN

This study examined whether cholecystectomy-induced DGR promotes chronic inflammatory mucosal changes of the stomach and/or the esophagogastric junction (EGJ). Four groups of patients were studied and compared with controls. A group of patients was studied before and 1 year after cholecystectomy; 2 further groups were studied long-term post-cholecystectomy (LTPC) at 5 to 10 years and 10 to 20 years. All underwent abdominal ultrasound and upper gastrointestinal endoscopy with gastric antral and EGJ biopsies, noting the presence of gastric bile pooling. Biopsy specimens were stained for Ki67 and p53 overexpression, and the bile reflux index (BRI) was calculated.

RESULTS

At endoscopy, bile pooling was observed in 9 of 26 (34.6%) controls, in 8 of 25 (32%) patients pre-cholecystectomy, in 15 of 25 (60%) 1 year post-cholecystectomy patients (p = 0.047), and 23 of 29 (79.3%) LTPC patients (p = 0.001). Bile reflux index positivity at the EGJ increased from 19% of controls through 41% of LTPC patients (p = 0.032). Ki67 was overexpressed at the EGJ in 19% of controls, but in 62% of LTPC patients (p = 0.044); p53 was overexpressed at the EGJ in 19% of controls compared with 66% of LTPC patients (p = 0.001).

CONCLUSIONS

Duodeno-gastric bile reflux was more common in patients with gallstones than in controls, and its incidence doubled after cholecystectomy. This was associated with inflammatory changes in the gastric antrum and the EGJ, evident in most LTPC patients. Ki67 and p53 overexpression at the EGJ suggests cellular damage attributable to chronic bile exposure post-cholecystectomy, increasing the likelihood of dysplasia. Further studies are required to determine whether DGR-mediated esophageal mucosal injury is reversible or avoidable, and whether surveillance endoscopy is indicated after cholecystectomy.

Correlation of the location of superficial Barrett's esophageal adenocarcinoma (s-BEA) with the direction of gastroesophageal reflux

BACKGROUND

Superficial Barrett's esophageal adenocarcinoma (s-BEA) in Barrett's esophagus frequently occurs in the right wall of the esophagus. Our aim was to examine the correlation between the location of s-BEA and the direction of acid and non-acid reflux in patients with Barrett's esophagus.

PATIENTS AND METHODS

We performed 24-h pH monitoring in 33 s-BEA patients using a pH catheter with eight sensors. One sensor was located at the 6 o'clock position in the lower esophagus and sensors 1 - 8 were arranged counterclockwise at the same level. The catheter was positioned at the same level as the s-BEA. We measured the maximal total duration of acid (MTD-A) and non-acid (MTD-NA) reflux. When the direction of MTD-A and MTD-NA coincided with the location of the s-BEA, the case was defined as coincidental and we calculated the rate of coincidence, and the probability of the rate of coincidence was estimated with 95 % confidence intervals (95 %CI).

RESULTS

Among the 33 cases of s-BEA examined, the rate of coincidence of both MTD-A and MTD-NA was 24/33 (72.7 %) (95 %CI 0.54 - 0.87). The rate of coincidence of either MTD-A or MTD-NA was 30/33 (90.9 %) (95 %CI 0.76 - 0.98).

CONCLUSIONS

Our study revealed that the location of s-BEA mostly corresponds to the direction of MTD-A or MTD-NA. Accurate observation of the distribution of acid or non-acid reflux by pH monitoring would aid early detection of s-BEA by endoscopy.

In vitro effects of rabeprazole on human pylorus tone

Background/Aims

It has been reported that proton pump inhibitors induce relaxation in different types of smooth muscles. The aim of this study is to investigate in vitro effects of proton pump inhibitors on human pylorus muscle.

Methods

Pyloric sphincters were studied in 10 patients who were operated for stomach cancer. In isolated organ bath, control and response to rabeprazole were recorded following contraction with carbachol. During the treatment experiment, while distilled water was applied during the control experiment in every 5 minutes, rabeprazole was administered in every 5 minutes at doses of 10⁻⁶, 10⁻⁵, 10⁻⁴, and 10⁻³ M respectively. Contraction frequencies, maximum contraction values and muscle tones were measured.

Results

The contraction frequencies in the control group were greater than the rabeprazole group in the second, third and fourth intervals while the maximum contraction values in the rabeprazole group were lower in the fourth interval. Even though muscles tones were not different in both groups during all intervals, it was remarkable that the muscle tone was significantly decreased in the rabeprazole group during the fourth interval compared to the first and second intervals.

Conclusions

In the present study, high doses of rabeprazole reduced contraction frequencies, maximum contraction values, and muscle tone of human pylorus.

Systematic toxicity mechanism analysis of proton pump inhibitors: an in silico study

Proton pump inhibitors (PPIs) are extensively used for the treatment of gastric acid-related disorders. PPIs appear to be well tolerated and almost have no short-term side effects. However, the clinical adverse reactions of long-term PPI usage are increasingly reported in recent years. So far, there is no study that elucidates the side effect mechanisms of PPIs comprehensively and systematically. In this study, a well-defined small molecule perturbed microarray data set of 344 compounds and 1695 samples was analyzed. With this high-throughput data set, a new index (Identity, I) was designed to identify PPI-specific differentially expressed genes. Results indicated that (1) up-regulated genes, such as RETSAT, CYP1A1, CYP1A2, and UGT, enhanced vitamin A's metabolism processes in the cellular retinol metabolism pathway; and that (2) down-regulated genes, such as C1QA, C1QC, C4BPA, C4BPB, CFI, and SERPING1, enriched in the complement and coagulation cascades pathway. In addition, strong association was observed between these PPI-specific differentially expressed genes and the reported side effects of PPIs by the gene-disease association network analysis. One potential toxicity mechanism of PPIs as suggested from this systematic PPI-specific gene expression analysis is that PPIs are enriched in acidic organelles where they are activated and inhibit V-ATPases and acid hydrolases, and consequently block the pathways of antigen presentation, the synthesis and secretion of cytokines, and complement component proteins and coagulation factors. The strategies developed in this work could be extended to studies on other drugs.

Upregulation of miRNA-143, -145, -192, and -194 in esophageal epithelial cells upon acidic bile salt stimulation

Barrett's esophagus (BE) is a metaplastic condition of the distal esophagus that occurs because of chronic gastroesophageal reflux. Previous studies have identified BE-specific microRNAs (miRNAs) in comparison with normal squamous epithelium (SQ). We hypothesized that BE-specific miRNAs could be induced in esophageal SQ cells by exposure to acid and/or bile salts. We aimed to determine whether BE-specific miRNAs are upregulated in an esophageal SQ cell line (Het-1A) in an environment with acid and/or bile salts and whether this is nuclear factor-κB (NF-κB) dependent. Acid and/or bile salt incubations were performed in Het-1A cells. Experiments were performed with or without inhibiting the NF-κB pathway. Quantitative reverse transcriptase polymerase chain reaction was performed to determine expression of miRNA-143, -145, -192, -194, cyclo-oxygenase-2 (COX2), mucin 2 (MUC2), and sex determining region Y-box 9. For validation, we determined levels of these miRNAs in biopsies from patients with reflux esophagitis and normal SQ. Significantly increased expression levels of miRNA-143 (2.7-fold), -145 (2.6-fold), -192 (2.0-fold), -194 (2.2-fold), COX2, MUC2, and sex determining region Y-box 9 were found upon acidic bile salt incubation, but not upon acid or bile salt alone. NF-κB pathway inhibition significantly decreased miRNA-143, -192, -194, COX2, and MUC2 expression. Additionally, miRNA-143, -145 and -194 expression was increased in reflux esophagitis biopsies compared with normal SQ, but no changes were found in miRNA-192 expression. Our findings suggest that upregulation of BE-specific miRNAs by acidic bile may be an early event in the transition of SQ to BE and that their expression is partly regulated by the NF-κB pathway.

Amiloride and guggulsterone suppression of esophageal cancer cell growth in vitro and in nude mouse xenografts

Esophageal adenocarcinoma is increasing in the US and Western countries and frequent gastresophageal reflux or gastresophageal reflux disease carrying gastric acid and bile acid could contribute to esophageal adenocarcinogenesis. This study was designed to detect the expression of gastric acid-inducing gene Na + /H + exchanger-1 (NHE-1) ex vivo and then to explore targeting of NHE-1 expression or activity to control esophageal cancer cell viability in vitro and in nude mouse xenografts. The data showed that NHE-1 was highly expressed in esophageal adenocarcinoma tissues (66 of 101 cases [65.3%], but not in normal esophageal squamous cell epithelium (1 of 26 cases [3.8%]). Knockdown of NHE-1 expression using NHE-1 shRNA or inhibition of NHE-1 activity using the NHE-1 inhibitor amiloride suppressed viability and induced apoptosis in esophageal cancer cells. Molecularly, amiloride inhibited expression of cyclooxygenase-2 and matrix metallopeptidase-9 but not NHE-1 mRNA in esophageal cancer cells. A combination of amiloride and guggulsterone (a natural bile acid receptor inhibitor) showed more than additive effects in suppressing esophageal cancer cell growth in vitro and in nude mouse xenografts. This study suggests that inhibition of NHE-1 expression or activity or combination of amiloride and guggulsterone could be useful in control of esophageal adenocarcinoma.

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

BACKGROUND

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

PURPOSE

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

Esophageal motility and impedance characteristics in patients with Barrett's esophagus before and after radiofrequency ablation

INTRODUCTION

Radiofrequency ablation (RFA) is a valuable treatment option in Barrett's esophagus resulting in eradication of dysplasia and conversion of all Barrett's epithelium into normal squamous epithelium. In Barrett's esophagus, esophageal impedance monitoring is hampered by low baseline impedance values. Whether these low baselines are caused by an intrinsically low impedance of cylindrical epithelium or by the excessive reflux itself is hitherto unknown. Data on esophageal motility after RFA are scarce. Our aim was to examine the effect of RFA on esophageal motility and esophageal baseline impedance in patients with Barrett's esophagus.

METHODS

In 10 patients, conventional esophageal manometry and 24-h pH-impedance measurements were performed before and after RFA. The number and type of reflux episodes were assessed and baseline impedance values were measured in all recording segments. In another five patients, high-resolution manometry was performed before and after RFA.

RESULTS

Complete regression of all Barrett's epithelium was achieved in all 15 patients after 3 ± 1 RFA sessions. Overall, no significant motility changes were found after RFA. Patients had excessive acid exposure times before and after RFA [25 (17-42) and 16 (9-24)%, respectively]. Baseline esophageal impedance values were low, with the lowest values in the distal recording segments. RFA increased baseline impedance in all recording segments in the upright position; in the supine position, the effect just failed to reach statistically significant levels.

CONCLUSION

RFA did not alter esophageal motility significantly. Low esophageal baseline impedance levels in patients with Barrett's esophagus reflect, at least in part, intrinsic impedance properties of cylindrical epithelium, as baselines increased after conversion into neosquamous epithelium.

Proton pump inhibitors reduce the risk of neoplastic progression in patients with Barrett's esophagus

BACKGROUND & AIMS

Acid exposure contributes to the development of Barrett's esophagus (BE) and its progression toward esophageal adenocarcinoma. Patients with BE are frequently treated with acid suppressants, but it is unclear whether these prevent the development of BE-related cancer. We investigated whether acid suppression reduces the risk of neoplastic progression in patients with BE.

METHODS

We performed a multicenter prospective cohort study of 540 patients with BE. We collected information on medication use at each surveillance visit, which was cross-checked with pharmacy records. Patients also completed a questionnaire about their use of over-the-counter medication. Incident cases of high-grade dysplasia and esophageal adenocarcinoma were identified during a median follow-up period of 5.2 years. Time-dependent Cox regression models were used to investigate the effect of acid suppression on the risk of neoplastic progression.

RESULTS

Forty patients (7%) developed high-grade dysplasia or esophageal adenocarcinoma during the follow-up period. Use of histamine-2 receptor antagonists did not affect the incidence of neoplastic progression. However, use of proton pump inhibitors (PPIs) at inclusion in the study or during the follow-up period reduced the risk of neoplastic progression (hazard ratio, 0.41; 95% confidence interval, 0.18-0.93 and hazard ratio, 0.21; 95% confidence interval, 0.07-0.66). Prolonged use of PPIs and good adherence were associated with an additional protective effect. The prevalence of esophagitis decreased during PPI use, but length of BE was not affected.

CONCLUSIONS

In a multicenter prospective cohort study, PPI use was associated with a reduced risk of neoplastic progression in patients with BE.

Why is there a change in patterns of GE cancer?

Recent decades have seen a worrying trend in incidence rates of distal oesophageal and proximal gastric cancers. Fuelled by radical changes in lifestyle, diet, physical activity and environmental exposures, as well as an ageing population and host genetic predisposition, the incidence of oesophageal adenocarcinoma (OAC) is on the rise in Western populations. While overall incidence of gastric cancers is declining, the ageing of society means that an increase in absolute numbers is expected over coming years. Both cancers tend to present at an advanced stage, hence prognosis remains poor despite increasingly effective screening and treatment strategies. The development of gastric and oesophageal malignancies is influenced by myriad factors, not least geographical, racial and socioeconomic differences in addition to lifestyle choices. The multidimensional nature of these risk factors requires a holistic understanding of their net influence in the development of malignancy. This review explores the evidence base for established and putative risk factors in the development of gastric and oesophageal cancers. It is hoped that with a clear understanding of important risk factors, a multidisciplinary approach including effective primary prevention, regular screening of high-risk groups and continued research into the molecular biology of gastrointestinal carcinogenesis may facilitate a reduction in incidence rates, as well as early detection and optimal management of upper gastrointestinal malignancies.

Bile salts disrupt human esophageal squamous epithelial barrier function by modulating tight junction proteins

Reflux of acid and bile acids contributes to epithelial tissue injury in gastro-esophageal reflux disease. However, the influence of refluxed material on human esophageal stratified epithelial barrier function and tight junction (TJ) proteins has not been fully elucidated. Here, we investigated the influence of acid and bile acids on barrier function and TJ protein distribution using a newly developed air-liquid interface (ALI) in vitro culture model of stratified squamous epithelium based on primary human esophageal epithelial cells (HEECs). Under ALI conditions, HEECs formed distinct epithelial layers on Transwell inserts after 7 days of culture. The epithelial layers formed TJ, and the presence of claudin-1, claudin-4, and occludin were detected by immunofluorescent staining. The NP-40-insoluble fraction of these TJ proteins was significantly higher by day 7 of ALI culture. Exposure of HEECs to pH 2, and taurocholic acid (TCA) and glycocholic acid (GCA) at pH 3, but not pH 4, for 1 h decreased transepithelial electrical resistance (TEER) and increased paracellular permeability. Exposure of cell layers to GCA (pH 3) and TCA (pH 3) for 1 h also markedly reduced the insoluble fractions of claudin-1 and -4. We found that deoxycholic acid (pH 7.4 or 6, 1 h) and pepsin (pH 3, 24 h) significantly decreased TEER and increased permeability. Based on these findings, ALI-cultured HEECs represent a new in vitro model of human esophageal stratified epithelium and are suitable for studying esophageal epithelial barrier functions. Using this model, we demonstrated that acid, bile acids, and pepsin disrupt squamous epithelial barrier function partly by modulating TJ proteins. These results provide new insights into understanding the role of TJ proteins in esophagitis.

Bile acids: from digestion to cancers

Bile acids (BAs) are cholesterol metabolites that have been extensively studied these last decades. BAs have been classified in two groups. Primary BAs are synthesized in liver, when secondary BAs are produced by intestinal bacteria. Recently, next to their ancestral roles in digestion and fat solubilization, BAs have been described as signaling molecules involved in many physiological functions, such as glucose and energy metabolisms. These signaling pathways involve the activation of the nuclear receptor FXRα or of the G-protein-coupled receptor TGR5. These two receptors have selective affinity to different types of BAs and show different expression patterns, leading to different described roles of BAs. It has been suggested for long that BAs could be molecules linked to tumor processes. Indeed, as many other molecules, regarding analyzed tissues, BAs could have either protective or pro-carcinogen activities. However, the molecular mechanisms responsible for these effects have not been characterized yet. It involves either chemical properties or their capacities to activate their specific receptors FXRα or TGR5. This review highlights and discusses the potential links between BAs and cancer diseases and the perspectives of using BAs as potential therapeutic targets in several pathologies.

The decreased expression of Beclin-1 correlates with progression to esophageal adenocarcinoma: the role of deoxycholic acid

Beclin-1 has a central role in the regulation of autophagy. Barrett's esophagus (BE) is associated with a significantly increased risk for the development of esophageal adenocarcinoma (EAC). In the current study, we evaluated the role of Beclin-1 and autophagy in the EAC. Biopsies obtained from patients with BE and EAC, tissues from a rat model of BE and EAC, and esophageal cell lines were evaluated for the expression of Beclin-1 by immunohistochemistry, immunoblotting, or RT-PCR. Since reflux of bile acids is important in EAC, we also evaluated the effect of exposure to deoxycholic acid (DCA) on autophagy and Beclin-1 expression. Beclin-1 expression was high in squamous epithelium and nondysplastic BE, whereas its expression was low in dysplastic BE and EAC. The same pattern of expression was observed in rat tissues and in esophageal cell lines. Normal esophageal epithelium and HET-1A cells (derived from normal squamous epithelium) show high levels of Beclin-1, but lower levels of Beclin-1 were found in BE and EAC cell lines (CP-A, CP-C, and OE33). Acute exposure to DCA led to increased Beclin-1 expression and increased autophagy as evaluated by electron microscopy and counting percentage of GFP-LC3-positive BE cells with punctate pattern. In contrast, chronic exposure to DCA did not result in the alteration of Beclin-1 levels or autophagy. In summary, these data suggest that autophagy is initially activated in response to bile acids, but chronic exposure to bile acids leads to decreased Beclin-1 expression and autophagy resistance.

Role of acid suppression in the development and progression of dysplasia in patients with Barrett's esophagus

Barrett's esophagus (BE) usually develops in patients with gastroesophageal reflux disease and therefore it has been suggested that esophageal acid exposure plays an import role in the initiation of BE and its progression towards esophageal adenocarcinoma (EAC). The mechanisms whereby acid exposure causes BE are not completely revealed and the potential role of esophageal acid exposure in carcinogenesis is unclear as well. Since acid exposure is thought to play an important role in the progression of BE, therapies aimed at preventing the development of EAC have primarily focused on pharmacological and surgical acid suppression. In clinical practice, acid suppression is effective in relieving reflux symptoms and decreases esophageal acid exposure in most patients. However, in some individuals, pathological acid exposure persists and these patients continue to be at risk for developing dysplasia or EAC. To date, published trials suggest that acid suppression is able to prevent the development and progression of dysplasia in patients with BE, but definite and compelling proof is still lacking. This article reviews the mechanisms of acid-induced carcinogenesis in BE and the role of acid suppression in the prevention of neoplastic progression.

Risk factors for neoplastic progression in Barrett’s esophagus

Barrett’s esophagus (BE) confers a significant increased risk for development of esophageal adenocarcinoma (EAC), with the pathogenesis appearing to progress through a “metaplasia-dysplasia-carcinoma” (MDC) sequence. Many of the genetic insults driving this MDC sequence have recently been characterized, providing targets for candidate biomarkers with potential clinical utility to stratify risk in individual patients. Many clinical risk factors have been investigated, and associations with a variety of genetic, specific gastrointestinal and other modifiable factors have been proposed in the literature. This review summarizes the current understanding of the mechanisms involved in neoplastic progression of BE to EAC and critically appraises the relative roles and contributions of these putative risk factors from the published evidence currently available.

The histological and immunohistochemical aspects of bile reflux in patients with gastroesophageal reflux disease

Introduction. The pathogenesis of GERD is strongly related with mixed acid and bile reflux. Benign and malignant esophageal and gastric lesions have been associated with synergetic activity between those parameters. Bile reflux causes reactive gastropathy evaluated with Bile Reflux Index (BRI). The aim was to investigate if the sequence: bile reflux-intestinal metaplasia-GERD-esophagitis, is associated with apoptotic/oncogenetic disturbances. Materials/Methods. Fifteen asymptomatic subjects and 53 GERD patients underwent gastroscopy with biopsies. The specimens examined histologically and immunohistochemically for p53, Ki-67, Bax, and Bcl-2. Results. Elevated BRI score detected in 47% (25/53) of patients with GERD and in 13% (2/15) of controls (P = 0.02). Severe esophageal lesions were significantly more common in BRI (+) patients (14/25) compared to BRI (-) ones (P = 0.0049). Immunohistochemical analysis did not show associations between BRI score and biomarker expression. Conclusions. Bile reflux gastropathy is associated with GERD severity, but not with oncogene expression or apoptotic discrepancies of the upper GI mucosa.

Laparoscopic Nissen-Rossetti fundoplication is a safe and effective treatment for both Acid and bile gastroesophageal reflux in patients poorly responsive to proton pump inhibitor

PURPOSE

The aim of this study was to evaluate the effectiveness of laparoscopic Nissen-Rossetti fundoplication in patients with gastroesophageal reflux disease (GERD) poorly responsive to standard dose proton pump inhibitor (PPI) therapy.

METHODS

A total of 35 patients (19 women, 16 men, mean age 44.6 ± 14.01 years) were enrolled. All the patients underwent symptom questionnaires, upper gastrointestinal endoscopy, esophageal manometry, and combined 24-hour esophageal pH and bilirubin monitoring. Following this, the patients with persistent pathological esophageal acid and/or bilirubin exposure underwent laparoscopic antireflux surgery, followed by clinical and instrumental 12-month follow-up.

RESULTS

One year after surgery, there was a significant improvement of symptom score, compared with standard PPI dose period (3.54 ± 1.67 vs 20.8 ± 10.9, P < .0001; paired t test) and mean percentage total time acid and bile exposure showed a significant decrease (4.9 ± 2.9 vs 2.03 ± 0.74 and 8.3 ± 3.03 vs 0.84 ± 0.56, P < .0001; paired t test).

CONCLUSIONS

In patients with GERD poorly responsive to standard PPI dose, laparoscopic Nissen-Rossetti fundoplication appears to be a safe and effective treatment of symptoms, esophageal damage, as well as both acid and bile reflux.

Induction of MUC5AC mucin by conjugated bile acids in the esophagus involves the phosphatidylinositol 3-kinase/protein kinase C/activator protein-1 pathway

BACKGROUND

Bile reflux contributes to the development of esophageal injury and neoplasia. The mucin 5AC (MUC5AC) is absent in the normal squamous epithelium of the esophagus but is strongly expressed in Barrett esophagus (BE). The objective of this study was to determine whether and how bile acids influence the expression of MUC5AC in the esophagus.

METHODS

MUC5AC expression was studied by immunohistochemistry and immunoblotting in human tissues, in tissues from a rat model of BE, and in SKGT-4 cultured esophageal epithelial cells. MUC5AC transcription was studied by real-time polymerase chain reaction and transient transfection assays.

RESULTS

MUC5AC was absent from normal squamous epithelium but was present in 100% of Barrett specimens and in 61.5% of human esophageal adenocarcinoma tissues that were examined. MUC5AC protein expression was induced to a greater degree by conjugated bile acids than by unconjugated bile acids, and this occurred at the transcriptional level. In the rat reflux model, MUC5AC mucin was expressed abundantly in tissues of BE stimulated by duodenoesophageal reflux. Conjugated bile acids induced AKT phosphorylation in SKGT-4 cells but had no effect on extracellular signal-regulated protein kinases 1 and 2, c-Jun N-terminal kinase, or protein-38 kinase phosphorylation. The phosphatidylinositol 3-kinase (PI3K) inhibitor LY294002 and a dominant-negative protein kinase C (AKT) construct prevented the induction of MUC5AC by conjugated bile acids. Transactivation of AP-1 by conjugated bile acids coincided with MUC5AC induction, and cotransfection with a dominant-negative activator protein-1 (AP-1) vector decreased MUC5AC transcription and its induction.

CONCLUSIONS

Conjugated bile acids in the bile refluxate contribute to MUC5AC induction in the esophagus. This occurs at the level of transcription and involves activation of the PI3K/AKT/AP-1 pathway.

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.

The resistance of esophageal adenocarcinoma to bile salt insult is associated with manganese superoxide dismutase expression

BACKGROUND

Bile acids are implicated as etiologic agents in esophageal cancer. We sought to analyze the impact of bile acid exposure on esophageal epithelial cells, Barrett's metaplastic cells (BE), esophageal adenocarcinoma cells (EAC), and esophageal squamous carcinoma cell (ESC). We sought to determine if cellular resistance is related to manganese superoxide dismutase expression.

METHODS

Cells were exposed to sodium choleate (CA), sodium deoxycholate (DCA), sodium glycocholate (GCA), sodium taurocholate (TCA), or a 1:1 mixture (MIX) of reagents at concentrations in the range 0.2-0.8 mM. Cell viability was evaluated by MTT assay. Manganese superoxide dismutase (MnSOD) expression was analyzed by Western blot. Statistical analysis was performed using SPSS ver. 17.0, SPSS Inc., Chicago, IL.

RESULTS

Bile salt exposure inhibited cell viability in esophageal squamous cells in time- and growth-dependent manner. There was a 50% decrease in cell viability from 4 to 24 h. BE, EAC, and ESC cell lines were more resistant to bile insult. In untreated cell lines, MnSOD expression was significantly decreased in EAC and ESC cell lines compared with esophageal squamous epithelial cells and BE cells (P=0.002). Exposure of ESC cells to bile salt increased MnSOD expression.

CONCLUSION

The confirmation of the role of reactive oxygen species (ROS) and bile acids in esophageal carcinogenesis has interesting implications for chemoprevention in patients with reflux esophagitis and Barrett's esophagus. Further studies are necessary to assess the preventative role of antioxidant supplementation.

Rabeprazole combined with hydrotalcite is effective for patients with bile reflux gastritis after cholecystectomy

BACKGROUND

Regardless of surgical technique, patients who have undergone cholecystectomy appear to be predisposed to the development of bile reflux gastritis.

OBJECTIVE

To assess the efficacy of rabeprazole and hydrotalcite in patients with bile reflux gastritis after cholecystectomy.

METHODS

Postcholecystectomy patients with bile reflux gastritis confirmed by endoscopy and 24 h gastric bilirubin monitoring were randomly assigned to one of four eight-week treatments: observation (group A), rabeprazole alone (group B), hydrotalcite alone (group C) and rabeprazole in combination with hydrotalcite (group D). Endoscopy and 24 h gastric bilirubin monitoring were repeated in all patients after treatment. Dyspeptic symptoms of abdominal pain, bloating, heartburn, bitter taste, endoscopic and histological finding, and biliary reflux were evaluated before and after treatment.

RESULTS

After administering medication, patient symptoms in groups B, C and D were relieved - most significantly in group D (P<0.05). There were no significant differences in endoscopic hyperemia and histological inflammation among the groups (P>0.05). However, histological activity, the number of reflux episodes and the number of reflux episodes lasting longer than 5 min were significantly decreased only in group D (P<0.05). The total per cent of bilirubin absorption (value of 0.14 units or greater) time was decreased in groups B, C and D, and most significantly in group D (P<0.05).

CONCLUSION

Rabeprazole combined with hydrotalcite is an effective therapeutic option in the treatment of patients with bile reflux gastritis after cholecystectomy.

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.

Bile acids as endogenous etiologic agents in gastrointestinal cancer

Bile acids are implicated as etiologic agents in cancer of the gastrointestinal (GI) tract, including cancer of the esophagus, stomach, small intestine, liver, biliary tract, pancreas and colon/rectum. Deleterious effects of bile acid exposure, likely related to carcinogenesis, include: induction of reactive oxygen and reactive nitrogen species; induction of DNA damage; stimulation of mutation; induction of apoptosis in the short term, and selection for apoptosis resistance in the long term. These deleterious effects have, so far, been reported most consistently in relation to esophageal and colorectal cancer, but also to some extent in relation to cancer of other organs. In addition, evidence is reviewed for an association of increased bile acid exposure with cancer risk in human populations, in specific human genetic conditions, and in animal experiments. A model for the role of bile acids in GI carcinogenesis is presented from a Darwinian perspective that offers an explanation for how the observed effects of bile acids on cells contribute to cancer development.

Risk factors and gene expression in esophageal cancer

Esophageal cancer is a significant worldwide health problem because of its poor prognosis and high incidence in certain parts of the world. Tobacco smoke and alcohol consumption are significant risk factors for esophageal squamous cell carcinoma, whereas frequent gastroesophageal reflux and subsequent inflammatory reactions play a role in causing the adenocarcinoma. Esophageal carcinogenesis involves multiple genetic alterations. A large body of knowledge has been generated regarding molecular alterations associated with esophageal carcinogenesis. These alterations include aberrant cell cycle control, DNA repair, cellular enzymes, growth factor receptors, and nuclear receptors. This chapter reviews the most frequent gene alterations and their correlation with risk factors as well as the prevention strategies in esophageal cancer.

Prevalence of pathological duodenogastric reflux and the relationship between duodenogastric and duodenogastrooesophageal reflux in chronic gastrooesophageal reflux disease

The role of duodenogastric reflux in gastrooesophageal reflux disease is still controversial.

AIMS

(i) To determine the prevalence of pathological duodenogastric reflux (DGR) in gastrooesophageal reflux disease patients and (ii) to define the relationship between DGR and duodenogastrooesophageal reflux.

METHODS

We evaluated 92 patients referred for investigation of recurrent reflux symptoms after proton pump inhibitors (PPI) therapy. All the patients filled out symptom questionnaires and underwent endoscopy, oesophageal manometry and combined oesophagogastric pH and bilirubin monitoring.

RESULTS

Endoscopy divided the 92 patients into four groups (group I: 25 nonoesophagitis patients, group II: 26 patients with grade A-B oesophagitis, group III: 21 patients with grade C-D oesophagitis and group IV: 20 patients with Barrett's oesophagus. Twenty-four of the 92 patients (26%) showed pathological DGR. Abnormal oesophageal bilirubin exposure was observed in 62 of the 92 patients (67.4%). Of the 62 patients with abnormal oesophageal bilimetry, 15 (24.2%) patients simultaneously showed pathological DGR. The gastric bilirubin exposure in patients with abnormal oesophageal, Bilitec tests did not differ from that in patients with normal oesophageal bilimetry (P>0.05). A weak correlation between oesophageal and gastric bilirubin exposure, both expressed as a percentage of time, was found (r=0.28; P<0.01).

CONCLUSION

Pathological DGR is present in a little more than a quarter of patients with recurrent reflux and dyspeptic symptoms after PPI therapy. Excessive DGR is not a prerequisite for pathological oesophageal exposure to duodenal contents. Gastric bilirubin monitoring may be useful to choose the best surgical treatment for patients with reflux and dyspeptic symptoms refractory to PPI.

Yield of 24-hour esophageal pH and bilitec monitoring in patients with persisting symptoms on PPI therapy

Current management algorithms propose pH monitoring under proton pump inhibitors (PPIs) in suspected gastroesophageal reflux disease (GERD) with insufficient treatment response, but recent observations challenge this approach because of its low yield.

AIM

To perform an audit of the outcomes of pH monitoring under PPI therapy in our unit, and to study the yield of additional nonacid reflux monitoring.

METHODS

All pH monitoring studies under antireflux therapy since 1997, with or without simultaneous Bilitec monitoring, were analyzed.

RESULTS

From 1997 to 2003, 347 patients (157 men, mean age 49.4 +/- 0.8 years) underwent pH studies on PPI therapy (28% half-, 67% full-, and 5% double-dose PPI) for persisting typical (53%) or atypical (75%) symptoms. In 184 patients, simultaneous Bilitec monitoring was performed. Esophageal pH monitoring on PPI was pathological in 105 (30%) patients. Pathological pH monitoring on PPI was associated with typical reflux symptoms (64 versus 52%, P = 0.03), and a higher prevalence of persisting esophagitis (54 versus 36%, P < 0.005) and of hiatal hernia (58 versus 27%, P < 0.005). Bilitec monitoring on PPI therapy was pathological in 114 (62%) patients, of which 74 (40%) had normal pH monitoring. Adding Bilitec increased the rate of abnormal results over pH monitoring alone, from 38% to 69% on half-dose, from 27% to 69% on full-dose, and from 0% to 38% on double-dose PPI.

CONCLUSIONS

The rate of abnormal pH monitoring in symptomatic GERD patients while on PPI therapy is relatively low, especially in those on double-dose PPI. Combined pH and Bilitec monitoring significantly increased the rate of ongoing pathological reflux compared to pH alone in refractory to PPI therapy GERD patients.

Increased prevalence of gallstone disease and impaired gallbladder motility in patients with Barrett's esophagus

The prevalence of gallstones in patients with Barrett's esophagus (BE) and their gallbladder motility relative to that of healthy volunteers and GERD patients without BE were investigated. Of the 707 patients reviewed, 203 (125 males and 78 females) had BE. The prevalence of gallstones was significantly higher in the patients with BE than in those without BE (34 vs. 20%, respectively). The gallbladder functions of 22 patients with GERD, 27 patients with BE and 21 healthy volunteers were assessed by ultrasonography before and after a test meal. The patients with BE had significantly higher fasting volume and residual volume, but lower ejection volume, ejection fraction and ejection rate values than those of the healthy controls. None of the ultrasonographic parameters of patients without BE were significantly different from those of the controls. Patients with BE have a more complex gastrointestinal motility disorder that involves the gallbladder, and this makes this subset of patients with GERD more prone to gallstone disease.

Effect of adiponectin and ghrelin on apoptosis of Barrett adenocarcinoma cell line

BACKGROUND

Obesity is an important risk factor for Barrett adenocarcinoma. However, the role of adiponectin (anti-inflammatory adipokine from adipose tissue) and ghrelin (orexigenic peptide gastric origin) on the progression of Barrett's carcinogenesis has not been investigated so far. The aim of the present study was: (1) to compare the expression of adiponectin and ghrelin receptors in Barrett's esophagus and in normal squamous epithelium; (2) to assess the effect of adiponectin and ghrelin on apoptosis in Barrett's adenocarcinoma cells in vitro; and (3) to investigate the effect of ghrelin on IL-1beta and COX-2 expression in OE-19 cells incubated with TNFalpha.

METHODS

The expression of ghrelin and adiponectin receptors (GHS-R1a, Adipo-R1, Adipo R-2) in biopsies from Barrett's esophagus and in Barrett's adenocarcinoma cell line OE-19 was assessed by quantitative RT-PCR (qRT-PCR). The OE-19 cells were also incubated with adiponectin (5-10 microg/ml), and the apoptosis and proliferation were assessed by FACS and MTT assays. Additionally, effects of adiponectin on the mRNA and protein expression of proapoptotic Bax and antiapoptotic Bcl-2 were assessed by RT-PCR and Western blot, respectively. In two different in vitro models of esophagitis the OE-19 cells were incubated with ghrelin alone or in the presence of TNFalpha or bile acids in the normal or pulse acidified medium, and the expression of IL-1beta and COX-2 as markers for inflammation were assessed by FACS and qRT-PCR, respectively.

RESULTS

Adiponectin caused a significant increase in apoptosis, and this affect was accompanied by increased Bax and decreased Bcl-2 expression. In contrast, ghrelin had no effect on apoptosis of OE-19 cells incubated in neutral or acidified medium with or without addition of deoxycholic acid. At the mRNA level, the expression of adiponectin receptors (Adipo-R1, Adipo-R2) was decreased, and the expression of ghrelin receptor (GHS-R1a) was increased in Barrett's mucosa. Ghrelin caused a decrease in TNFalpha-induced COX-2 and IL-1beta expression in OE-19 cells.

CONCLUSION

Adiponectin and ghrelin have an inhibitory effect on Barrett's carcinogenesis by two different mechanisms: (1) by an increase in apoptosis by adiponectin, and (2) by anti-inflammatory actions of ghrelin. The decrease in levels of these two peptides in obesity may explain the progression of Barrett's carcinoma in obese individuals.

Refractory gastrooesophageal reflux disease

The introduction of proton pump inhibitors (PPIs) has facilitated the treatment of gastrooesophageal reflux disease (GORD) enormously; however, treatment of GORD still fails in a small proportion of patients. This small proportion of therapy-resistant patients encompasses a substantial part of the working load of physicians and has become a common clinical problem. A strong variability in acid-suppressive effect of PPI treatment exists depending on compliance, Helicobacter pylori status and genotype. Nocturnal acid breakthrough does not seem to be a major determinant of refractory GORD. Recent data, however, show that PPI-refractory GORD can result from nonacid reflux episodes. It is wise to reconsider the diagnosis of GORD in patients who are PPI-refractory. Most patients in whom a PPI is not effective do not have GORD, instead they suffer from other disorders such as functional dyspepsia. If after a thorough history is taken the suspicion of GORD is still high, the next step would be to perform upper endoscopy and reflux monitoring. In case patients truly have PPI-refractory GORD, therapy can be aimed at oesophageal hypersensitivity or a surgical solution can be sought.

Prevalence of Barrett's esophagus in individuals without typical symptoms of gastroesophageal reflux disease

BACKGROUND: Barrett’s esophagus, the major risk factor for esophageal adenocarcinoma, is detected in approximately 10%-14% of individuals submitted to upper endoscopy for the assessment of gastroesophageal reflux disease related symptoms. Prevalence studies of Barrett’s esophagus in individuals without typical symptoms of gastroesophageal reflux disease have reported rates ranging from 0.6% to 25%. AIM: To determine the prevalence of Barrett’s in a Brazilian population older than 50 years without typical symptoms of gastroesophageal reflux disease. METHODS: A total of 104 patients (51 men), mean age of 65 years, with an indication for upper endoscopy but without symptoms of heartburn and/or acid regurgitation (determined with a validated questionnaire) were recruited. Subjects submitted to upper endoscopic examination in the last 10 years or using antisecretory medication (proton pump inhibitors) during the last 6 months were not included. Methylene blue chromoscopy was performed during the endoscopic exam to facilitate identification of the metaplastic epithelium. RESULTS: Barrett’s esophagus was diagnosed endoscopically and confirmed by histology in four patients, all of them males. The metaplastic segment was short (less than 3 cm) and free of dysplasia in all patients. The prevalence of Barrett’s esophagus was 7.75% in the male population and 3.8% in the general population studied. CONCLUSION: Due to the low prevalence of Barrett’s esophagus found in the present study, associated with the finding of short-segment Barrett’s esophagus in all cases diagnosed and the absence of dysplasia in the material analyzed, endoscopic screening for Barrett’s esophagus in patients above the age of 50 without the classical symptoms of gastroesophageal reflux disease is not indicated for the Brazilian population.

Barrett's esophagus and severe reflux esophagitis share common pathophysiological characteristics among Chinese in Taiwan

OBJECTIVE

The pathophysiological data on Barrett's esophagus are scant in Asia, so the purpose of this study was to compare and analyze the pathophysiological characteristics of Barrett's esophagus and reflux esophagitis among Chinese in Taiwan.

PATIENTS AND METHODS

From November 2001 to January 2003, fifteen patients with Barrett's esophagus were consecutively enrolled as the Barrett's esophagus group. Fourteen patients with Los Angeles grade A/B esophagitis (mild esophagitis group) and fourteen patients with LA grade C/D esophagitis (severe esophagitis group) who were matched in age and gender with the Barrett's esophagus group were enrolled. The data of esophageal manometry and ambulatory 24-hour pH monitoring were collected.

RESULTS

We found that the Barrett's esophagus group had significantly weaker lower esophageal sphincter (LES) pressure and distal esophageal body contractions (p<0.05) than the mild esophagitis group. Both the Barrett's esophagus group and severe esophagitis group had significantly higher esophageal acid reflux scores and frequency (p<0.05-0.01) compared to the mild esophagitis group. However, data on esophageal manometry and 24-hour pH monitoring in the Barrett's esophagus and severe esophagitis groups did not significantly differ.

CONCLUSION

We concluded that Barrett's esophagus had significantly stronger acid reflux, lower LES pressure, and weaker distal esophageal peristalsis compared to mild esophagitis. Barrett's esophagus and severe reflux esophagitis share common pathophysiological characteristics among Chinese in Taiwan.

Prevalence and topography of intestinal metaplasia in columnar lined esophagus

OBJECTIVES

Barrett's mucosa is considered as a mosaic of three epithelial types but little is known about the topography of intestinal metaplasia in columnar lined esophagus. The aims of the study were to determine the prevalence of intestinal metaplasia within long and short segments of columnar lined esophagus and to analyze the distribution of the intestinal metaplasia within long segments of Barrett's esophagus.

PATIENTS AND METHODS

The study was performed on the initial endoscopy carried out among 112 patients enrolled in an endoscopic surveillance program. Seventy-two patients with columnar mucosa extending more than 3 cm into the esophagus (group I) and 40 patients with a short segment of columnar mucosa (group II) had multiple biopsies according to a standardized protocol. 1163 biopsies were analyzed on the whole: 949 biopsies in group I and 214 biopsies in group II.

RESULTS

Intestinal metaplasia was identified among 650 (68.5%) and 50 (23.4%) biopsies in groups I and II respectively (P<10-7). The proportion of biopsies with foci of intestinal metaplasia increased significantly with the length of the columnar mucosa. The diagnosis of Barrett's esophagus was confirmed in 100% of the patients in group I and in 45% of the patients in group II. In long segments of Barrett's esophagus, intestinal metaplasia was more frequently observed in the 2 upper thirds of the columnar mucosa that in the lower third (P<10-7). Detailed mapping of the distribution of epithelial types within the columnar lined esophagus identified three patterns of distribution of intestinal metaplasia within long segments of Barrett's esophagus: unifocal, multifocal and diffuse, in 5%, 56% and 39% of the patients respectively. Dysplasia was present in 15% of patients with long segments of Barrett's esophagus and 11% of patients with short segments (NS).

CONCLUSION

The distribution of intestinal metaplasia within columnar lined esophagus is heterogeneous and three distinct patterns can be identified: unifocal, multifocal and diffuse. Considering the risk of sampling error, the current recommendations concerning the biopsy protocols are mandatory until the validation of new techniques such as chromoendoscopy or magnifying endoscopy.

A rat surgical model of esophageal metaplasia and adenocarcinoma-induced by mixed reflux of gastric acid and duodenal contents

Recent clinical data have revealed that mixed reflux (MR) of gastric acid and duodenal contents frequently occurs in patients with gastroesophageal reflux disease and a progressive increase of MR occurs with increasing severity across gastroesophageal reflux disease. Herein we report a novel rat surgical model in which esophageal metaplasia and adenocarcinoma develop as complications of MR. The model was created by performing an esophagojejunostomy and a gastrojejunostomy 5 mm proximal to the esophagojejunal anastomosis in 40 rats. Severe inflammatory and proliferative changes, high prevalence of esophageal metaplasia (78%), and adenocarcinoma (50%) were observed in the lower part of the esophagus of rats 20 weeks after surgery. The resulting esophageal lesions resembled those described in humans and supported a progression from intestinal metaplasia to dysplasia and, ultimately, esophageal adenocarcinoma. Such a model may provide a useful tool in study of human reflux-induced carcinogenesis.

Duodenogastro-esophageal reflux in children with refractory gastro-esophageal reflux disease

OBJECTIVE

To determine the role of duodenogastro-esophageal reflux (DGER) in the pathogenesis of refractory gastro-esophageal reflux disease (GERD) in children.

STUDY DESIGN

Twenty-two patients (12 boys, mean age, 13.2 years) with GERD symptoms that persisted on omeprazole (1 mg/kg) underwent upper gastrointestinal endoscopy and barium x-ray, 24-hour pH and DGER (Bilitec) monitoring, and a 13C octanoic acid gastric emptying breath test.

RESULTS

Patients presented mainly with epigastric pain, regurgitation, and nausea. Endoscopy revealed persistent esophagitis in 15 patients (68%). Pathologic acid and DGER exposure were present in 12 (55%) and 15 (68%) children, respectively, with combined pathologic reflux in 10 (45%). Acid exposure did not differ according to the presence of esophagitis, but patients with grade II esophagitis had significantly higher DGER exposure than those without esophagitis (9.1 +/- 5.3% vs 26.7 +/- 10.9% of the time, P < .05). Gastric emptying rate was not associated to acid or DGER exposure or persisting esophagitis. Symptoms improved after adding a prokinetic drug to the proton pump inhibitor therapy or referral for surgery (n = 5).

CONCLUSIONS

DGER may play a role in the pathophysiology of proton pump inhibitor-refractory GERD and esophagitis in children.

Do acid and bile reflux into the esophagus simultaneously? Temporal relationship between duodenogastro-esophageal reflux and esophageal pH

BACKGROUND

Duodenogastro-esophageal reflux (DGER) is an important factor in the pathogenesis of reflux esophagitis. Animal studies have demonstrated that the injurious effect of duodenal juice components depends on pH. The purpose of the present study was to investigate the temporal relationship between DGER and esophageal pH.

METHODS

Seventy-six children with symptoms of gastro-esophageal reflux disease (27 without, 31 with mild, 18 with severe esophagitis) underwent 24 h simultaneous esophageal pH and bilirubin monitoring with Bilitec 2000. The recordings were analyzed for (i) pH at the beginning of DGER episodes; (ii) relative duration of DGER in eight defined pH intervals of 1 pH unit; and (iii) differences in relative duration of DGER between the three groups of children.

RESULTS

DGER episodes most frequently began at pH between 6 and 7. DGER was present in the esophagus across the spectrum of esophageal pH, with the biggest relative duration between pH 3 and 5. However, in children without esophagitis relative duration of DGER was longest between pH 5 and 6, in children with mild esophagitis between pH 4 and 5, while in those with severe esophagitis it was between pH 2 and 4 (P < 0.001).

CONCLUSIONS

DGER appears across the whole esophageal pH spectrum. The more severe the esophagitis, the lower the pH at which DGER occurs, resulting in simultaneous damaging effects of acid and duodenal juice components.

Bile acids and Barrett's oesophagus: a sine qua non or coincidence?

BACKGROUND

Barrett's oesophagus (BO), a premalignant condition associated with the development of oesophageal adenocarcinoma (OAC), is thought to be a consequence of chronic duodeno-gastro-oesophageal reflux. Of the refluxates, bile acids, either alone or in combination with acid, are probably the most important.

METHODS

Analysis of the literature on the role played by bile acids in inducing BO and/or progression to OAC.

RESULTS

Combined pH and Bilitec 2000 (as a measure of bile reflux) monitoring and oesophageal aspiration studies in humans suggest a combined role for bile acids, particularly taurine conjugated bile acids, in causing oesophageal mucosal injury. Evidence from animal models has demonstrated that duodenal juice alone is also able to induce BO and/or OAC. Likewise, ex vivo studies with biopsies from BO patients show that increased proliferation and cyclo-oxygenase-2 expression are present after a pulsed exposure to acid or conjugated bile acids, but not if acid and bile acids are combined. Proton-pump inhibitors (PPIs) have been shown to decrease the biliary component of the refluxate. There is some evidence that PPIs are able to reduce neoplastic progression in BO. On the other hand, chronic PPIs can also stimulate bacterial overgrowth, which can result in increased production of secondary bile acids, particularly deoxycholic acid, in the stomach. Deoxycholic acid has been demonstrated to have a tumour-promoting capacity.

CONCLUSIONS

It is unknown what factors of the refluxate (acid and/or bile) induce BO and/or promote carcinogenesis, but there is evidence that secondary bile acids play a role. A better understanding of the molecular steps involved in the induction of BO, and the role of bile acids herein, may identify targets at which preventive therapies can be directed.

Multilayered epithelium may be found in patients with Barrett's epithelium and dysplasia or adenocarcinoma

To determine if multilayered epithelium (MLE) is a useful prognostic indicator for a benign natural history of Barrett's epithelium, we evaluated endoscopic biopsies from patients with Barrett's epithelium without and with dysplasia and/or adenocarcinoma and from non-Barrett's controls for the presence of MLE. MLE was found in 6% of non-Barrett's controls, 30% of Barrett's patients with no dysplasia, and 14% of Barrett's patients with dysplasia and/or adenocarcinoma. MLE was significantly associated with shorter lengths of Barrett's epithelium in both Barrett's groups. Three of 5 photodynamic therapy patients were noted to develop MLE after therapy. MLE may be found in patients with dysplasia and/or adenocarcinoma and after photodynamic therapy; its presence is not useful as a prognostic indicator for a more benign course of Barrett's. This study confirms that MLE is significantly associated with shorter lengths of Barrett's epithelium.