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

Review article: human pepsins - their multiplicity, function and role in reflux disease

Human gastric juice contains a multiplicity of proteinases. These are classified as aspartic proteinases because of enzymic activity dependent on two oppositely placed aspartic acids in the active site region. At least seven zones of activity can be visualized by agar gel electrophoresis and a similar number of separate proteins resolved by high performance ion exchange chromatography. The major enzyme secreted (up to 70% of the total) pepsin 3b is sensitive to the selective inhibitor pepstatin whereas gastricsin or pepsin 5 (20% of the total) is not. Minor enzymes including pepsin 1, which has an associated proteincarbohydrate complex attached is variable and can be < 5% in normal and up to 20% of the total as in peptic ulcer patients. The activity of these enzymes depends on the substrate and pH with significant digestion occurring up to pH 4.5. It has also been shown that these enzymes can bind to substrates like collagen up to pH 5.5. In gastric secretion studies of patients with reflux oesophagitis the amount of pepsin and the profile of the enzymes in basal secretions, and that after pentagastrin stimulation, was found to be not different from healthy non-refluxers. Thus the problem with reflux is that gastric juice appears in the oesophagus, an area without any natural protection from proteolytic damage. The ability to reduce gastric secretion is therefore important in effective treatment. However, being able also to inhibit enzymic activity or protect substrates from damage using alginates offers considerable scope for future therapies.

Review article: the role of bile and pepsin in the pathophysiology and treatment of gastro-oesophageal reflux disease

Gastro-oesophageal reflux disease is a multifaceted and multifactorial disorder which results from the reflux of gastric contents into the oesophagus. Animal studies suggest that synergism between acid and pepsin and conjugated bile acids have the greatest damaging potential for oesophageal mucosa, although unconjugated bile acids may be caustic at more neutral pH. Human studies are compatible with a synergistic action between acid and duodenogastric reflux in inducing lesions. During prolonged monitoring studies, typical gastro-oesophageal reflux symptoms are more related to acid reflux events than to non-acid reflux events. However, symptoms that persist during acid suppressive therapy are often related to non-acid reflux events. The therapeutic options for the non-acid component of the refluxate, including acid suppression, prokinetics, baclofen, surgery and mucosal protective agents like alginates, are discussed.

Dickkopf homologs in squamous mucosa of esophagitis patients are overexpressed compared with Barrett's patients and healthy controls

OBJECTIVES

Esophageal mucosal response to acid exposure varies from minimal changes to erosions/ulcerations and Barrett's metaplasia. While differences in acid contact time have been suggested, the reason for these different responses is not completely understood. The aim of this study was to identify and compare gene expression differences between normal distal and proximal squamous esophageal mucosa (SM) in esophagitis patients with that of healthy controls and Barrett's patients.

METHODS

Gene microarray was performed on laser-capture microdissected epithelial cells isolated from biopsy specimens followed by real-time PCR. The effect of acidic pH (pH 4.5) on Dickkopf Homolog 1 (Dkk-1) expression in the human esophageal epithelial cell line (Het-1A) was determined.

RESULTS

Gene microarray analysis demonstrated that the upregulation of five genes in the distal compared with the proximal SM in esophagitis patients was greater than the healthy controls and Barrett's patients. Overexpression of Dkk-1 and Dkk-4 was further confirmed by real-time PCR. Dkk-1 and Dkk-4 mRNA levels in the distal SM of the esophagitis patients were 7.0- and 3.1-fold higher, respectively, than in the distal SM of the Barrett's patients and 4.1- and 4.1-fold higher than in healthy controls, respectively. Dkk-1 protein expression in the distal esophagitis SM was also higher than the Barrett's patients and healthy controls. Acidic pH exposure of Het-1A cells resulted in Dkk-1 upregulation at the level of both mRNA and protein.

CONCLUSIONS

Dkk-1 and Dkk-4 may potentially be involved in the development of different injuries in response to pathological gastroesophageal acid reflux.

Effects of low-power argon plasma coagulation thermoablation of Barrett's epithelium on oesophageal motility

INTRODUCTION

Oesophageal dysmotility contributes to the pathogenesis of Barrett's epithelium (BE) allowing prolonged mucosal contact with injurious refluxate. Argon plasma coagulation (APC) is effective for BE ablation, but it is unknown whether the procedure affects oesophageal motility.

AIM

To assess the effect of low power (30 W) APC therapy on oesophageal motility in patients with BE.

METHODS

Thirty-three patients with at least 4 cm of BE underwent oesophageal manometry before and after APC ablation. All were on proton pump inhibitors. Oesophageal body peristaltic wave duration and amplitude, and lower oesophageal sphincter (LOS) pressure and length were compared before and after treatment.

RESULTS

In a total of 28 men and five women, with a mean age of 63.4 years (range 39-79) and mean BE length 6.5 cm (range 4-19), macroscopic clearance was achieved in 28 patients. A small statistically significant (P<0.05) increase in peristaltic wave amplitude was seen after APC [mean (SD) mmHg before versus after: 30.4 (15.2) versus 36.2 (20.1) at 13.5 cm, 47.6 (27.1) versus 54.5 (26.8) at 8.5 cm, and 51.2 (35.3) versus 58 (34.4) at 3.5 cm above the LOS]. No changes in either peristaltic wave duration or LOS parameters [mean (SD) pressure 10.6 (5.6) versus 10.3 (4.3) mmHg; length 2.8 (1.3) versus 2.8 (1.0) cm] were observed.

CONCLUSION

APC ablation of BE at a power setting of 30 W does not impair oesophageal motility.

Colorectal neoplasia in veterans is associated with Barrett's esophagus but not with proton-pump inhibitor or aspirin/NSAID use

BACKGROUND

It has been suggested that Barrett's esophagus (BE) is associated with an increased risk of developing colorectal neoplasia, but this has not been reported consistently.

AIM

To study whether BE is associated with an increased risk of colorectal neoplasia, and if it is, whether it is dependent on use of proton-pump inhibitors (PPIs) or aspirin and nonsteroidal anti-inflammatory drugs (NSAIDs).

DESIGN

Case-control study.

SETTING

Endoscopic database of the Palo Alto Veterans Affairs Health Care System.

POPULATION

268 veterans with BE were matched with 268 controls without BE.

INTERVENTION

Controls had undergone upper GI endoscopy within 14 days of the corresponding case. Colonoscopy was performed within 6 months in cases and controls.

MAIN OUTCOME MEASURE

Development of colorectal neoplasia.

RESULTS

Colorectal neoplasia was present in 162 of 268 (60%) BE patients and in 105 of 268 (40%) controls (p < 0.001). The presence of BE (odds ratio [OR] 2.02: 95% CI [1.35, 3.04]), but also increasing age (OR 1.24 per decade: 95% CI [1.04, 1.48]) and alcohol use (OR 1.70: 95% CI [1.16, 2.50]) were associated with an increased risk of colorectal neoplasia in multivariable logistic regression analysis, whereas PPIs (OR 0.99: 95% CI [0.66, 1.48]) and aspirin/NSAIDs (OR 0.90: 95% CI [0.61, 1.33]) had no meaningful effect.

LIMITATIONS

This was a retrospective study in mostly male veterans.

CONCLUSIONS

Veterans with BE are at an increased risk of developing colorectal neoplasia. This association is independent from the use of PPIs or aspirin/NSAIDs.

Review article: role of pepsin and bile in gastro-oesophageal reflux disease

Gastro-oesophageal reflux disease is defined as the presence of symptoms or lesions that can be attributed to the reflux of gastric contents into the oesophagus. Aspiration and prolonged monitoring studies in humans have shown that reflux of gastric contents is comprised of both acid and non-acid components, in healthy as well as diseased people. Methods to monitor the non-acid component of the refluxate are described in detail. Experimental models suggest that synergism between acid and pepsin and conjugated bile acids have the greatest damaging potential for oesophageal mucosa, although unconjugated bile acids may be caustic at a more neutral pH. Human studies are compatible with a synergistic action between acid and duodenogastric reflux in inducing lesions. During prolonged monitoring studies, typical gastro-oesophageal reflux disease symptoms are more related to acid reflux events than to non-acid reflux events. However, symptoms that persist during acid-suppressive therapy are often related to non-acid reflux events. The therapeutic options for the non-acid component of the refluxate, including acid suppression, prokinetics, baclofen and surgery, are discussed.

Risk factors, DNA damage, and disease progression in Barrett's esophagus

Esophageal adenocarcinoma develops on a background of Barrett's esophagus. A number of risk factors have been linked to both conditions, including gastroesophageal reflux and smoking. However, the molecular mechanisms by which these factors influence disease progression remain unclear. One possibility is that risk factors generate promutagenic DNA damage in the esophagus. The comet assay was used to measure DNA damage in esophageal (Barrett's and squamous) and gastric mucosa of Barrett's patients with (n = 24) or without (n = 50) associated adenocarcinoma or high-grade dysplasia in comparison with control patients (squamous mucosa) without Barrett's esophagus (n = 64). Patients completed a questionnaire detailing exposure to some of the known risk factors for Barrett's esophagus and adenocarcinoma. In Barrett's esophagus patients, DNA damage was higher in Barrett's mucosa compared with normal esophageal and gastric mucosa (P < 0.001). In addition, the highest quartile of DNA damage in Barrett's mucosa was associated with an increased risk (odds ratio, 9.4; 95% confidence interval, 1.1-83.4; P = 0.044) of developing adenocarcinoma or high-grade dysplasia compared with DNA damage levels in the lowest quartile. Smoking was associated with higher DNA damage in squamous epithelium in all patient groups (P < 0.01) and in Barrett's mucosa (P < 0.05) in Barrett's esophagus patients only. In controls only, current reflux was associated with higher DNA damage, whereas anti-inflammatory drug use resulted in lower levels. Collectively, these data imply a genotoxic insult to the premalignant Barrett's mucosa that may explain the genetic instability in this tissue and the progression to adenocarcinoma. There is an indication for a role for smoking in inducing DNA damage in esophageal mucosa but an understanding of the role of reflux requires further investigation.

Bile acids as carcinogens in human gastrointestinal cancers

Bile acids were first proposed to be carcinogens in 1939 and 1940. On the basis of later work with rodent models, bile acids came to be regarded as cancer promoters rather than carcinogens. However, considerable indirect evidence, obtained more recently, supports the view that bile acids are carcinogens in humans. At least 15 reports, from 1980 through 2003, indicate that bile acids cause DNA damage. The mechanism is probably indirect, involving induction of oxidative stress and production of reactive oxygen species that then damage DNA. Repeated DNA damage likely increases the mutation rate, including the mutation rate of tumor suppressor genes and oncogenes. Additional reports, from 1994 through 2002, indicate that bile acids, at the increased concentrations accompanying a high fat diet, induce frequent apoptosis. Those cells within the exposed population with reduced apoptosis capability tend to survive and selectively proliferate. That bile acids cause DNA damage and may select for apoptosis-resistant cells (both leading to increased mutation), indicates that bile acids are likely carcinogens. In humans, an increased incidence of cancer of the laryngopharyngeal tract, esophagus, stomach, pancreas, the small intestine (near the Ampulla of Vater) and the colon are associated with high levels of bile acids. The much larger number of cell generations in the colonic (and, likely, other gastrointestinal) epithelia of humans compared to rodents may allow time for induction and selection of mutations leading to cancer in humans, although not in rodents.

Does laparoscopic Nissen fundoplication prevent the progression of Barrett's oesophagus? Is the length of Barrett's a factor?

Introduction:

Recent studies have suggested that both laparoscopic and open anti-reflux surgery may produce regression of Barrett’s mucosa.

Material and methods;

We reviewed 21 patients (13M: 8F, mean age 46.7±3.18 years) with documented Gastroesophageal Reflux Disease (GERD) and Non-dysplastic Barrett’s esophagus (15 patients ?3 cm segment, 6 patients < 3 cm segment) on long term proton pump inhibitor therapy who underwent laparoscopic Nissen fundoplication (LNF) between 1993 and 2000. All patients had undergone pre and yearly postoperative upper GI endoscopy with 4 quadrant biopsies every 2 cm. All patients also underwent pre- and 6 months postoperative 24-hr pH study, esophageal manometry, SF36, and GERD symptom score. The mean duration of GERD symptoms was 8.4±1.54 years pre-operative. The mean follow-up after surgery was 39±6.32 months.

Results:

Postoperatively, there was significant improvement in reflux symptom score (37.5 ± 3.98 points versus 8.7 ± 2.46 points, P = 0.0001), % acid reflux in 24 hr (26.5 ± 3.91% versus 2.1 ± 0.84%, P< 0.0001) and an increase in lower esophageal sphincter pressure (3.71 ± 1.08 mmHg versus 12.29 ± 1.34 mmHg, P = 0.0053). Complete or partial regression of Barrett’s mucosa occurred in 9 patients. All patients with complete regression had <4 cm segment of Barrett’s. Progression or cancer transformation was not observed in any of the patients.

Conclusion:

LNF in patients with Barrett’s oesophagus results in significant control of GERD symptoms. LNF can prevent progression of Barrett’s oesophagus and in patients with Barrett’s <4 cm may lead to complete regression.

Barrett's esophagus in females: a comparative analysis of risk factors in females and males

OBJECTIVES

Gastroesophageal reflux symptoms occur with similar frequency in males and females, yet Barrett's esophagus is less common in females. The reason for this disparity is unknown. The aim of this study was to determine the factors related to Barrett's in females.

METHODS

The records of 796 patients (462 male, 334 female) evaluated from 1990 to 2000 for symptoms of reflux were retrospectively reviewed. Physiologic abnormalities based on results of endoscopic, motility, pH, and Bilitec testing were identified, and factors related to the presence of Barrett's were determined using univariate and multivariate analysis.

RESULTS

Females with reflux symptoms were significantly less likely to have a positive 24-h pH test, a defective lower esophageal sphincter, or a hiatal hernia than males with reflux symptoms. Further, females with reflux on the basis of an abnormal 24-h pH test had significantly less esophageal acid exposure than males with reflux. In contrast, esophageal exposure to refluxed acid and bilirubin was similar in females (n = 50) and males (n = 136) with Barrett's. On multivariable analysis increased esophageal bilirubin exposure was the only significant factor associated with the presence of Barrett's in male and female patients with reflux disease.

CONCLUSIONS

Females with reflux symptoms have less esophageal acid exposure on average than males. However, females and males with Barrett's have a similar severity of reflux, and the female gender does not protect against the development of Barrett's in the setting of advanced reflux disease. Esophageal bilirubin exposure is the major risk factor for the presence of Barrett's in patients with reflux disease.

Barrett esophagus: will effective treatment prevent the risk of progression to esophageal adenocarcinoma?

Barrett esophagus is a complication of long-standing gastroesophageal reflux disease (GERD) and is the well-recognized premalignant condition for the majority of esophageal and gastroesophageal junction adenocarcinomas. Although duration of gastroesophageal reflux (GER), male sex, and, possibly, a strong family history are directly related to risk of Barrett esophagus, the role of screening in those with GERD and surveillance in those with confirmed Barrett syndrome remains controversial. Acid suppression with proton pump inhibitor (PPI) therapy plays a pivotal role in the management of symptoms in persons with chronic GER and Barrett esophagus. Although there is no conclusive evidence for the role of PPIs in regression of Barrett epithelium or prevention of dysplasia, longer-term studies that titrate the dose to normalization of esophageal pH may proffer different data in the future. Although highly touted in the literature, surgical and endoscopic ablation therapies are limited by several factors, including high rates of symptom recurrence, persistently abnormal pH values, need for repeat surgery, and, in the case of endoscopic therapy, residual Barrett metaplasia that can progress to high-grade dysplasia or cancer. These invasive interventions should only be considered after consultation with a gastroenterologist. Cancer chemoprevention strategies are just emerging, and their roles as direct chemoprotectants remain to be determined.

Gastroesophageal reflux disease poorly responsive to single-dose proton pump inhibitors in patients without Barrett's esophagus: acid reflux, bile reflux, or both?

OBJECTIVES

Studies using ambulatory pH and esophageal bile reflux monitoring (Bilitec) have shown that both acid reflux and duodeno-gastro-esophageal reflux (DGER) frequently occur in patients with gastroesophageal reflux disease (GERD). A subset of patients with GERD has persistent reflux symptoms in spite of standard doses of proton pump inhibitors (PPIs). The aim of the present study was to investigate the role of acid and DGER in patients with reflux disease poorly responsive to PPIs.

METHODS

Sixty-five patients (32 men, 44 +/- 2 yr) without Barrett's esophagus and with persistent heartburn or regurgitation during standard PPI doses were studied. They underwent upper gastrointestinal endoscopy and simultaneous 24-h ambulatory pH and Bilitec monitoring while PPIs were continued.

RESULTS

Thirty-three patients (51%) had persistent esophagitis. Seven patients (11%) had only pathological acid exposure, 25 (38%) had only pathological DGER exposure, and 17 (26%) had pathological exposure to both acid and DGER. Acid exposure under PPI was positive in only 37%, but adding Bilitec increased the diagnoses of persistent reflux to 75%. Patients with persistent esophagitis had similar acid exposure, but significantly higher DGER exposure than those without esophagitis. The highest prevalence of esophagitis was found in patients with pathological exposure to both acid and DGER; symptoms did not differ according to the type of reflux.

CONCLUSIONS

Combined pH and Bilitec monitoring is superior to pH monitoring alone in demonstrating ongoing pathological reflux in patients with medically poorly responsive reflux disease.

Peptic esophageal stricture: a report from Argentina

Peptic esophageal stricture (PES) is a major complication of gastroesophageal reflux disease. The aims of this paper were to determine the characteristics of these patients with regard to demography, morphology, functional status and results of therapy. The charts of the patients treated at our service who underwent esophageal dilatation for PES between 1971 and 1998 were reviewed. Statistical analyses were performed by means of chi2, Mann-Whitney and Student's t-tests. One hundred and thirty-five patients with PES were dilated by various means. The mean age was 61.1 +/- 16.3 years, the ratio of men to women was 2.75/1 and mean duration of symptoms was 44.4 +/- 74.6 months. Their symptoms were dysphagia in 100%, pyrosis in 70%, and regurgitation in 40% of the cases. There was an average weight loss of 3.3 +/- 6 kg. The upper gastro-intestinal series showed pre- and post-dilatation diameters at the stricture of 8 +/- 2.5 mm and 15.9 +/- 1.2 mm, respectively. The stricture was located at the lower third of the esophagus in 97% and at the middle third in 3% of the cases. We found PES endoscopically in all instances, with different degrees of erosions in 64%, ulcers in 20% and Barrett's esophagus in 16% of the cases. The biopsy samples showed intestinal metaplasia in 16% and esophagitis in 75.5%, being normal in the remaining 8.5%. Brush cytology was negative for malignancy in 100% of the cases. Esophageal manometry showed peristaltic wave amplitude of 40 +/- 3 mmHg and presence of peristaltic waves of 62 +/- 38.6%. LES pressure was 8.6 +/- 6.3 mmHg (NV 24.2 +/- 6.3 mmHg). Measurement of pH showed 15% of patients had pH < 4. Patients needed a mean of 4.7 +/- 1.6 dilations per case, with successful results in 87.2% of cases. The perforation rate was 0.1% of the total number of procedures and 0.7%, of patients. The mortality rate was 0.7% (one case). We observed PES relapse in 32% of the cases. There was no correlation between relapse, age, duration of the stenosis or pharmacological treatment with H2 blockers or proton pump inhibitors. We conclude that in Argentina, demography, morphology, functional status and results of dilatation of PES patients are similar to those reported in the Western world, with the exception of the different behavior seen after treatment with H2 blockers or proton pump inhibitors.

Effects of bile reflux and intragastric microflora changes on lesions of remnant gastric mucosa after gastric operation

AIM: To investigate the effects of bile reflux and intragastric microflora changes on lesions of remnant gastric mucosa after gastric operation.

METHODS: Concenration of bile acid and total bacterial counts (TBC) in gastric juice were measured in 49 patients with peptic ulcer before and after gastrectomy. One year after the operation, sample of gastric mucosa taken from all the patients were used for histological examination.

RESULTS: The concentration of gastric bile acid was significantly increased in group B-I, or B-II and SV + A than that in group HSV (P < 0.05-0.01). The abnormal histological changes in the remnant gastric mucosa were more common in the first 2 groups than in the last group.

CONCLUSION: The type of gastrtectomy can affect bile reflux. The abnormal histological changes in the remnant gastric mucosa are closely related to the elevation of bile acid concentration and increase of TBC in gastric juice. HSV can effectively prevent bile reflux and keep the gastric physiological functions stable.

Review article: approaches to Barrett's oesophagus treatment-the role of proton pump inhibitors and other interventions

Despite implementation of screening and surveillance strategies, a significantly large number of patients with Barrett's oesophagus remain undiagnosed. In those who are identified, the management options include acid reduction therapies with proton pump inhibitors or anti-reflux surgery. Endoscopic ablative therapies have also been attempted. In addition to having inherent procedure-related risks with ablative therapies, these alternatives may be limited by high rates of failure, need for continued acid suppressive therapy, metaplasia persistence under otherwise normal appearing tissue, need for procedural expertise, and continued risk for adenocarcinoma development. Therefore, a widely applicable chemoprevention strategy that cost-effectively reduces the rate of progression from oesophagitis to adenocarcinoma in high-risk patients and perhaps those at lower rates of risk is highly desirable. The AspECT trial currently underway is seeking to determine the effects of high- and low-dose proton pump inhibitor therapy with and without low-dose aspirin as Barrett's oesophagus chemoprevention.

Efficacy of laparoscopic antireflux surgery in patients with Barrett's esophagus

BACKGROUND

Laparoscopic antireflux surgery (LARS) corrects significant physiologic and anatomic abnormalities in patients with gastroesophageal reflux disease (GERD); however, debate exists whether LARS prevents recurrent symptoms and malignant transformation in patients with Barrett's esophagus (BE). This study compared clinical outcomes after LARS in patients with and without BE.

METHODS

From 1994 to 2001, 448 patients who underwent LARS were studied. Of these, 68 (15%) had preoperative evidence of BE with low-grade dysplasia in 3 (4%), and 380 (85%) were without BE. Mean postoperative follow-up was more than 30 months in each group.

RESULTS

After LARS, there was equivalent reduction in acid reduction medication use and typical GERD symptoms in both groups. Anatomic failures developed in 12% of patients with BE and in 5% of those without BE (P = 0.05). Upper endoscopy with biopsies was obtained in 50 of 68 patients (74%) with BE at 37 +/- 22 months postoperatively. Intestinal metaplasia was no longer present in 7 of 50 (14%) BE patients, and low-grade dysplasia regressed to nondysplastic Barrett's in 2 of 3 patients. New low-grade dysplasia developed in 1 BE patient (2%) at postoperative endoscopic surveillance. No BE patients developed high-grade dysplasia or adenocarcinoma.

CONCLUSIONS

After LARS, patients with BE have symptomatic relief and reduction in medication use equivalent to non-BE patients. Regression of intestinal metaplasia and the absence of progression to high-grade dysplasia or adenocarcinoma suggest that LARS is an effective approach for the management of patients with Barrett's esophagus. The higher failure rate of LARS in BE is of concern and mandates ongoing follow-up of these patients.

Barrett's esophagus: environmental influences in the progression of dysplasia

Barrett's esophagus (BE) is composed of multiple lineages including Paneth cells and endocrine cells in addition to gastric and intestinal cells. Although the origin of the BE stem cell is a matter of conjecture, the stem cells are clearly multipotent, and therefore the phenotype is restricted by genomic imprinting (termed restricted potency). Recent evidence suggests that the microenvironment may select various lineages. In this regard the proportion of gastric and specialized intestinal metaplastic cells has been attributed to the composition of the refluxate, acid or bile, respectively. Experimental evidence also implicates specific xenobiotics in this process, including bile acids. In particular we discuss the potential biologic roles of bile acids in epithelial adaptation from in vivo and in vitro models.

Reflux, Barrett's oesophagus and adenocarcinoma: burning questions

The incidence of oesophageal adenocarcinoma is increasing rapidly in Western populations. Gastro-oesophageal reflux disease is a strong risk factor for both this tumour and the pre-cancerous lesion Barrett's oesophagus, but the underlying disease mechanisms remain unclear. Developing a better understanding of the aetiology and pathogenesis of Barrett's oesophagus, including the induction of DNA damage and genetic alterations, might provide opportunities for improved management of individuals with this disease. This could include a better rationale for screening and surveillance programmes, as well as targeted intervention strategies.

Argon plasma coagulation in Barrett's esophagus

Despite the availability of many clinical trials, there is no evidence that APC has any role in the management of Barrett's esophagus. Ablation therapy is not indicated for nondysplastic Barrett's esophagus (and this is true, whatever the technique used), and it should not be performed outside of a carefully designed and approved clinical trial. Indeed, these patients have a low risk of cancer, and there is no evidence that Barrett's esophagus ablation will be of any benefit for these patients. In some cases, APC could be of some help, especially for treating short segments of dysplastic Barrett's esophagus. In this field, however, it competes with the growing indication of mucosectomy, which clearly offers advantages in terms of treatment's quality control assessment.

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.

Antireflux surgery for Barrett's oesophagus

Barrett's oesophagus is usually the result of severe reflux disease. Relief of reflux symptoms is the primary aim of treatment in patients with Barrett's oesophagus who do not have high-grade dysplasia. Some studies with medium-term (2-5 years) follow up show that antireflux surgery can provide good or excellent symptom control, with normal oesophageal acid exposure, in more than 90% of patients with Barrett's oesophagus. Antireflux surgery, but not medical therapy, can also reduce duodenal nonacid reflux to normal levels. There is no conclusive evidence that antireflux surgery can prevent the development of dysplasia or cancer, or that it can reliably induce regression of dysplasia, and patients with Barrett's oesophagus should therefore remain in a surveillance programme after operation. Some data suggest that antireflux surgery can prevent the development of intestinal metaplasia (IM) in patients with reflux disease but no IM. The combination of antireflux surgery plus an endoscopic ablation procedure is a promising treatment for patients with Barrett's oesophagus with low-grade dysplasia.

Bile in the esophagus: a factor in the pathogenesis of reflux esophagitis in children

OBJECTIVES

Bile reflux has been postulated to be an important factor contributing to gastroesophageal reflux disease in adults. The purpose of this study was to investigate its role in children.

METHODS

Sixty-five children with symptoms of gastroesophageal reflux disease were classified on the basis of the endoscopic grade of reflux esophagitis: no esophagitis (n = 26), mild to moderate esophagitis (n = 26), and severe esophagitis (n = 13). Simultaneous 24-hour esophageal pH and bilirubin monitoring with Bilitec 2000 was performed.

RESULTS

Both bile and acid reflux increased with the severity of esophagitis. The differences between all groups were significant for the percentage of total (P < 0.0005), upright (P < 0.05), and supine time (P < 0.0005) bilirubin absorbance > or = 0.14, as well as for the percentage of total and supine time pH < 4, and DeMeester score (P < 0.0005). Combined pathologic acid and bile reflux was found in 11% of children with mild esophagitis and in 70% of children with severe esophagitis, while isolated bile reflux was found in 31% and 7.5%, respectively. Combined pH and bilirubin monitoring, compared with ph-monitoring alone, increased the sensitivity from 56% to 79%, and the accuracy from 69% to 83%.

CONCLUSIONS

Both bile and acid reflux increase stepwise with the severity of esophagitis. Combined acid and bile reflux is associated with severe esophagitis. Isolated acid or bile reflux is usually present in mild esophagitis. Simultaneous esophageal pH and bilirubin monitoring has a higher sensitivity, as well as predictive values and accuracy than ph monitoring alone.

Gastroesophageal reflux disease revisited

GERD should be viewed as three distinct groups of patients: NERD, erosive esophagitis, and Barrett's esophagus. This new paradigm will shift our focus to mechanisms leading to symptom generation in each group and foster specific therapeutic modalities that benefit each individual group of patients.

Gastroesophageal reflux disease

Gastroesophageal reflux disease (GERD) affects many patients and has a negative effect on quality of life. Along with the increasing prevalence of GERD is an increase in GERD-related complications, including Barrett esophagus and esophageal adenocarcinoma. The past year has yielded new insights into the pathophysiology of GERD that can help us to better understand the relationship between reflux episodes and symptoms of mucosal damage and to provide a tailored treatment targeting individual pathophysiologic defects. The issues addressed in this report include gastric secretory and motor dysfunction; failure of the antireflux barrier caused by hiatal hernia and transient lower esophageal sphincter relaxations; characterization of the refluxate, particularly of nonacid reflux; prevalence and prognostic value of esophageal dysmotility in GERD; presence and eradication of Helicobacter pylori; Barrett esophagus and extraesophageal manifestations of GERD; and, finally, advances in medical, endoscopic, and surgical treatments of GERD.

Barrett esophagus

A number of publications have provided valuable insight into and data on the epidemiology, pathogenesis, diagnosis, risk factor evaluation, and treatment of patients with Barrett esophagus. Although the incidence of esophageal adenocarcinoma has rapidly increased over the past two decades, it is not clear whether there has been a parallel increase in the frequency of Barrett esophagus. The issue of surveillance endoscopy in patients with Barrett esophagus remains controversial; prospective data are still lacking. Bile reflux plays an important role in the pathogenesis of Barrett esophagus; however, this usually occurs in the presence of acid. Newer technology and techniques, including chromoendoscopy, magnification endoscopy, optical coherence tomography, and spectroscopy, have opened the field by providing a more accurate and "nonbiopsy" diagnosis of intestinal metaplasia and dysplasia. The field of biomarkers remains continues to expand and is providing insight into risk stratification of patients with Barrett esophagus. The exact role of acid suppression in patients with this premalignant disease remains controversial, and endoscopic therapies appear promising.

Barrett's esophagus: surveillance and treatment

Barrett's esophagus is a disease of paramount importance dictated by its exponentially increasing incidence and association with esophageal cancer. Unfortunately, our knowledge lacks much of the key data and information to make those important decisions in Barrett's as regards screening and treatment. With an evident lack of long-term large population studies of patients with Barrett's esophagus, much of our decision making is based on little available data and becomes somewhat arbitrary. Given these limitations, screening criteria include adults with a long history of persistent reflux symptoms. The precise age, frequency, and duration of symptoms used is unclear. Once Barrett's is identified, endoscopic surveillance is performed every 2 years, but this interval will most likely lengthen to 3 years. For patients with LGD, surveillance every 6-12 months is recommended. For HGD, esophagectomy is still recommended for healthy surgical candidates, but more patients will be followed, particularly those with "focal" HGD. The role of acid suppression either pharmacologically or surgically is not clear, but the tendency is to achieve near complete control of the acid reflux. Endoscopic ablative procedures are experimental and may be indicated in patients at high surgical risk with HGD and carcinoma. Its role in mainstream practice is yet to be defined.

Physiology and pathology of the oesophagus in the elderly patient

In the 1960s, the term 'presbyoesophagus' was introduced for what were felt to be the characteristics of the oesophagus in old age. Since then a number of sophisticated studies using modern manometric, radiological, pH-metric or endoscopic equipment have been performed to better study this subject. Although results in some aspects are still contradictory, these studies have provided us with some more detailed information on the physiology of the ageing oesophagus. Beginning with an overview of what is currently known and discussed about age-induced physiological changes in oesophageal function, this review will then focus on specific problems of oesophagus-related diseases in the elderly. The main topics discussed will include presentation, diagnosis and treatment of primary and secondary motility disorders, oesophageal manifestations of neuromuscular and neurological disease, gastro-oesophageal reflux disease and oesophageal cancer in the elderly.