Duodenogastroesophageal reflux: relationship to pH and importance in Barrett's esophagus

Impact of the composition of gastric reflux bile acids on Barrett's oesophagus

BACKGROUND

The effect of the composition of reflux bile acids, especially the ratio of hydrophobic to hydrophilic ones, on the development of Barrett's oesophagus has not been fully investigated in human studies.

AIMS

To evaluate the influence of the bile acid composition of gastric juice on Barrett's oesophagus, a prospective study was designed.

METHODS

Fifty patients with and 100 patients without Barrett's oesophagus were enrolled. For all enrolled patients, gastric juice was collected by the endoscopic procedure for bile acid analysis. The ratio of hydrophobic to hydrophilic bile acids (bile hydrophobicity ratio, BHR) was calculated from 6 kinds of bile acids analysed in gastric juice. The relationship between the ratio and clinico-pathological factors of Barrett's oesophagus was investigated.

RESULTS

The mean of BHR of patients with Barrett's oesophagus was significantly higher than that of patients without Barrett's oesophagus (0.26 ± 0.05 vs. 0.08 ± 0.02, p<0.05). In multivariate analysis, a high BHR value was a predictor for the presence of Barrett's oesophagus (OR 5.74, p<0.001). In patients with Barrett's oesophagus, the BHR correlated with COX-2 protein expression and with accelerated cellular proliferation.

CONCLUSIONS

Patients with Barrett's oesophagus had a higher BHR in the gastric juice than those without.

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.

Role of Th-2 cytokines in the development of Barrett's esophagus in rats

BACKGROUND

Barrett's esophagus is characterized by a distinct Th-2-predominant cytokine profile, unlike the pro-inflammatory nature of reflux esophagitis. The aim of this study was to examine the role of Th-2 cytokines during the development of Barrett's esophagus, using a rat model.

METHODS

Barrett's esophagus was induced by Levrat's esophagojejunostomy technique in Brown-Norway (BN) rats. Rats were killed at 8, 15, 30, and 50 weeks after the operation. We studied the incidences of esophagitis and Barrett's esophagus, and the mRNA expression of cytokines and CDX2 by real-time reverse transcriptase-polymerase chain reaction and immunohistochemical staining. Finally, we compared the incidence of Barrett's esophagus in BN rats with that in Sprague-Dawley (SD) rats.

RESULTS

Esophagitis was found in all rats. Barrett's esophagus appeared 8 weeks after the operation, and its incidence and length increased over time. Levels of Th-2 cytokines such as interleukin (IL)-4, IL-10, and IL-13 were significantly increased in Barrett's esophagus as compared to those in non-Barrett's esophagus, while there were no differences in the levels of pro-inflammatory cytokines. The peak of elevated IL-4 mRNA was observed before that of CDX2 mRNA. IL-4 was co-localized in CD4-positive cells and CDX2-positive goblet cells. The incidence of Barrett's esophagus was more common in BN rats (8/10, 80%) than in SD rats (2/7, 28%) at 30 weeks.

CONCLUSION

Th-2 cytokines, especially IL-4, may play a crucial role in the development of Barrett's esophagus in an early phase. These results provide understanding of the pathogenesis of Barrett's esophagus from the aspect of the Th-2 immune response.

In vitro and ex vivo models of extended reflux exposure demonstrate that weakly acidic mixed reflux heightens NF-kB-mediated gene expression

The development of Barrett's esophagus and its progression to adenocarcinoma are clearly linked to reflux of acid and bile. Our objective in this study was to develop an optimized ex vivo biopsy culture technique to study the molecular signaling events induced after insult with individual refluxate constituents. We illustrate the utility of this method by showing results for NF-kB centered cell signaling, and compare the results with those obtained from esophageal cell lines. We show that upregulation of the two NF-kB target genes show differences in pH preference, with IL-8 being preferentially upregulated by DCA at neutral pH, and IkB being upregulated by neutral DCA, acidic DCA, and acid alone. This was found to be true in both cell lines and biopsy cultures. The maximum responses were noted in both models when mixed reflux (DCA at pH 6) was utilized, perhaps reflecting the pH preference of DCA (pKa 6.2). Both the optimized ex vivo models, and the in vitro cell lines show that bile and acid are capable of inducing NF-kB dependent gene expression, with some interesting differences in preferred transcriptional target. In conclusion, in both cells and cultured biopsies, similar reflux driven gene expression changes were noted, with maximum effects noted with DCA exposures at pH 6.

Does impaired gallbladder function contribute to the development of Barrett's esophagus and esophageal adenocarcinoma?

INTRODUCTION

Esophageal adenocarcinoma is aetiologically associated with gastro-esophageal reflux, but the mechanisms responsible for the metaplasia-dysplasia sequence are unknown. Bile components are implicated. Impaired gallbladder function may contribute to duodenogastric reflux (DGR) and harmful GERD.

AIMS

This study aims to compare gallbladder function in patients with Barrett's esophagus, adenocarcinoma, and controls.

METHODS

Three groups of patients, all free of gallstone disease, were studied. Group 1: (n = 15) were normal controls. Group 2: (n = 15) were patients with >3-cm-long segment of Barrett's esophagus. Group 3: (n = 15) were patients with esophageal adenocarcinoma. Using real-time ultrasonography unit, gallbladder volume was measured in subjects following a 10-h fast. Ejection fraction was calculated before and after standard liquid meal and compared between the groups.

RESULTS

The mean percentage reduction in gallbladder volume was 50% at 40 min in the adenocarcinoma group compared with 72.4% in the control group (p < 0.001). At 60 min, gallbladder filling had recommenced in the control group to 64.1% of fasting volume while continuing to empty with further reduction to 63% in the Barrett's group and to 50.6% (p = 0.008) in the adenocarcinoma group. The mean gallbladder ejection fraction decreased progressively from controls to Barrett's to adenocarcinoma and was significantly lower in Barrett's group (60.9%; p = 0.019) and adenocarcinoma group (47.9%; p < 0.001) compared with normal controls (70.9%).

CONCLUSION

Gallbladder function is progressively impaired in Barrett's esophagus and adenocarcinoma. Gallbladder malfunction increases duodenogastric reflux, exposing the lower esophagus to an altered chemical milieu which, in turn, may have a role in promoting metaplasia-dysplasia-neoplasia sequence in the lower esophageal mucosa.

Effect of low-proof alcoholic beverages on duodenogastro-esophageal reflux in health and GERD

BACKGROUND

Alcoholic beverages are known to increase acidic gastro-esophageal reflux (GER) and the risk of esophagitis. Moreover, duodenogastro-esophageal reflux (DGER), containing bile acids, was shown to harmfully alter the esophageal mucosa, alone and synergistically with HCl and pepsin. However, studies directly addressing potential effects of different low proof alcoholic beverages on DGER in health and disease are missing.

METHODS

Bilitec readings for beer and white, rose, and red wine were obtained in vitro from pure and from mixtures with bile. One-hour DGER monitoring and pH-metry were performed in 12 healthy subjects and nine reflux patients with DGER after ingestion of a standardized liquid meal together with 300 mL of water, white wine, and in the volunteers, beer and rose wine.

KEY RESULTS

Bilitec measurement was found to be feasible in the presence of beer, white wine, and using a threshold of 0.25, rose wine. However, the presence of red wine resulted in extinction values above this threshold. The consumption of all investigated alcoholic beverages, especially of white wine, triggered increased acidic GER, both in healthy participants and patients with reflux disease. In contrast, no relevant DGER was found after intake of alcoholic beverages.

CONCLUSIONS & INFERENCES

Fiber-optic bilirubin monitoring can be used for DGER monitoring in combination with alcoholic beverages, except with red wine. Low-proof alcoholic beverages are a strong trigger of GER, but not of DGER, both in healthy subjects and patients with reflux disease.

Proton pump inhibitor therapy improves symptoms in postnasal drainage

BACKGROUND & AIMS

Gastroesophageal reflux is common among patients with postnasal drainage. We investigated whether proton pump inhibitor therapy improved symptoms in patients with postnasal drainage without sinusitis or allergies.

METHODS

In a parallel-group, double-blind, multi-specialty trial, we randomly assigned 75 participants with continued symptoms of chronic postnasal drainage to groups that were given 30 mg of lansoprazole twice daily or placebo. Participants were followed up for 16 weeks. Symptoms were assessed at baseline and after 8 and 16 weeks. Ambulatory pH and impedance monitoring assessed presence of baseline reflux. The primary objective of the study was to determine if acid suppressive therapy improved postnasal drainage symptoms. The secondary objective was to assess if pH and impedance monitoring at baseline predicted response to treatment.

RESULTS

Postnasal drainage symptoms improved significantly among patients given lansoprazole compared with placebo. After 8 and 16 weeks, participants given lansoprazole were 3.12-fold (1.28-7.59) and 3.50-fold (1.41-8.67) more likely to respond, respectively, than participants given placebo. After 16 weeks, median (interquartile) percent symptom improvements were 50.0% (10.0%-72.0%) for participants given lansoprazole and 5.0% (0.0%-40.0%) for participants given placebo (P = .006). Neither baseline presence of typical reflux symptoms nor esophageal physiologic parameters predicted response to therapy.

CONCLUSIONS

Among participants with chronic postnasal drainage without evidence of sinusitis and allergies, twice-daily therapy with proton pump inhibitors significantly improved symptoms after 8 and 16 weeks. The presence of heartburn, regurgitation, abnormal levels of esophageal acid, or nonacid reflux did not predict response to therapy.

An algorithm for diagnosis and treatment of refractory GERD

Patients with gastro-esophageal reflux disease (GERD) who are not responding to proton pump inhibitors (PPIs) given once daily are very common. These therapy-resistant patients have become the new face of GERD in clinical practice in the last decade. Upper endoscopy appears to have a limited diagnostic value. In contrast, esophageal impedance with pH testing on therapy appears to provide the most insightful information about the subsequent management of these patients. Commonly, doubling the PPI dose or switching to another PPI will be offered to patients who failed PPI once daily. Failure of such therapeutic strategies is commonly followed by assessment for weakly or residual acidic reflux. There is growing information about the potential value of compounds that can reduce transient lower esophageal sphincter relaxation rate. Esophageal pain modulators are commonly offered to patients with functional heartburn although supportive clinical studies are still missing.

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 pathogenesis of Barrett's metaplasia and the progression to esophageal adenocarcinoma

The most important risk factor for the development of Barrett's esophagus is the reflux of both gastric and duodenal contents into the esophagus. The reason why Barrett's metaplasia develops only in a minority of patients suffering from gastroesophageal reflux disease remains unknown.The exact mechanism behind the transition of normal squamous epithelium into specialized columnar epithelium is also unclear. It is likely that stem cells are involved in this metaplastic change, as they are the only permanent residents of the epithelium. Several tumorigenic steps that lead to the underlying genetic instability, which is indispensable in the progression from columnar metaplasia to esophageal adenocarcinoma have been described. This review outlines the process of pathogenesis of Barrett's metaplasia and its progression to esophageal adenocarcinoma.

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

BACKGROUND

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

METHODS

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

KEY RESULTS

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

CONCLUSIONS & INFERENCES

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

Exogenous luminal nitric oxide exposure accelerates columnar transformation of rat esophagus

Exposure of the esophageal mucosa to refluxed gastroduodenal contents is recognized to be an important risk factor for Barrett's esophagus (BE). At the human gastroesophageal junction, nitric oxide is generated luminally through the enterosalivary recirculation of dietary nitrate, and in cases with gastroesophageal reflux, the site of luminal nitric oxide generation could shift to the distal esophagus. The aim of this study is to investigate whether exogenous luminal nitric oxide could promote the development of BE in rats. Sodium nitrite plus ascorbic acid were administered to a rat surgical model of BE, in which the gastroduodenal contents were refluxed into the esophagus to generate exogenous luminal nitric oxide in the esophagus by the acid-catalyzed chemical reaction between the 2 reagents. The emergence of BE was evaluated histologically in the early phase (several weeks) after the surgery with or without exogenous nitric oxide administration. To elucidate the histogenesis of BE, CDX2, MUC2 and MUC6 expressions were investigated immunohistochemically. Coadministration of sodium nitrite plus ascorbic acid significantly accelerated the timing of emergence and increased the area of BE compared with controls. Administration of either reagent alone did not show any promotive effects on BE formation. Immunohistochemically, the columnar epithelium thus induced was similar to the specialized intestinal metaplasia in human BE. The results of this animal model study suggest that exogenous luminal nitric oxide could be involved in the pathogenesis of the columnar transformation of the esophagus. Further studies in human are warranted.

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

BACKGROUND

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

AIM

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

The role of weakly acidic reflux in proton pump inhibitor failure, has dust settled?

Patients that do not respond satisfactorily to standard proton pump inhibitor (PPI) treatment have become the most common presentation of gastro-esophageal reflux disease (GERD) in third referral gastrointestinal practices. The causes of refractory GERD include lack of compliance with treatment, residual acid reflux and weakly acidic reflux, esophageal hypersensitivity and persistent symptoms not associated with reflux. A role for weakly acidic reflux in symptom generation has been proposed since the availability of impedance-pH monitoring. The possible mechanisms by which persistent weakly acidic reflux might contribute to persistent symptoms in patients under PPI treatment may include esophageal distension by increased reflux volume, persistent impaired mucosal integrity (ie, dilation of intercellular spaces) and/or esophageal hypersensitivity to weakly acidic reflux events. To establish a definite role of weakly acidic reflux in refractory GERD, outcome studies targeting this type of reflux are still lacking. Treatment strategies to reduce the number or effect of weakly acidic reflux could involve drugs that decrease transient lower esophageal sphincter relaxations (ie, baclofen or similar), improve oesophageal mucosa resistance or visceral pain modulators. Finally, anti-reflux surgery can be considered, only if a clear symptom-weakly acidic reflux association was demonstrated.

Management of gastroesophageal reflux disease that does not respond well to proton pump inhibitors

PURPOSE OF REVIEW

Patients with gastroesophageal reflux disease (GERD) who are not responding to proton pump inhibitors (PPIs) given once daily are very common. These therapy-resistant patients have become the new face of GERD in clinical practice in the last decade and presently pose a significant therapeutic challenge to the practicing physician. We reviewed newly accumulated information about the management of PPI failure that has been published over the past 2 years.

RECENT FINDINGS

There are diverse mechanisms that contribute to the failure of PPI treatment in GERD patients and they are not limited to residual reflux. Some of the causes of PPI failure may coincide in the same patient. Upper endoscopy appears to have limited diagnostic value. In contrast, esophageal impedance with pH testing on therapy appears to provide the most insightful information about the subsequent management of these patients. Commonly, doubling the PPI dose or switching to another PPI will be offered to patients who failed PPI once daily. Failure of such therapeutic strategies is commonly followed by assessment for residual reflux. There is growing information about the potential value of compounds that can reduce transient lower esophageal sphincter relaxations. Esophageal pain modulators are commonly offered to patients with functional heartburn, although supportive clinical studies are still missing.

SUMMARY

Management of refractory GERD patients remains an important clinical challenge. Recent studies have cemented the value of impedance-pH testing in pursuing proper treatment. Presently, the most promising therapeutic development for this patient population is transient lower esophageal sphincter relaxation reducers.

Long-term outcome of microscopic esophagitis in chronic GERD patients treated with esomeprazole or laparoscopic antireflux surgery in the LOTUS trial

OBJECTIVES

Gastroesophageal reflux disease (GERD)-associated changes in esophageal histology have been reported mainly after short-term medical antireflux therapy, and few individual lesions have been examined. We report detailed histological findings from the LOTUS study, at baseline and at 1 and 3 years after laparoscopic antireflux surgery (LARS) or esomeprazole treatment in patients with chronic GERD.

METHODS

LOTUS is a long-term, open, parallel-group, multicenter, randomized, controlled trial conducted in 11 European countries that compared LARS (n=248) with esomeprazole 20-40 mg daily (n=266). Biopsies from the distal esophagus 2 cm above the Z-line and at the Z-line were taken at baseline, and 1 and 3 years. The following lesions were assessed: basal cell hyperplasia (BCH), papillary elongation (PE), intercellular space dilatations (ISDs), intraepithelial eosinophils (EOSs), neutrophils, and necrosis/erosion. A severity score (SS, range 0-2) was calculated by taking the average score of all assessable lesions.

RESULTS

All lesions were more severe on Z-line biopsies than at 2 cm, and almost all improved significantly from baseline to 1 and 3 years. The average SS (from 2 cm to Z-line) changed from 0.95 to 0.57 (1 year) and to 0.49 (3 years) on esomeprazole, and from 0.91 to 0.56 (1 year) and to 0.52 (3 years) after LARS (P<0.001 for both treatments at 1 and 3 years, with no significant difference between treatments). The proportions of patients with severe histological changes decreased from approximately 50% at baseline to 11% at 3 years.

CONCLUSIONS

Both continuous esomeprazole treatment and laparoscopic fundoplication are associated with significant and similar overall improvement in microscopic esophagitis after 1 year that is maintained at 3 years.

Gastric surgery is not a risk factor for erosive esophagitis or Barrett's esophagus

OBJECTIVE

The role of gastric acid reflux is difficult to separate from that of pancreatic-biliary reflux in the pathogenesis of erosive esophagitis (EE) and Barrett's esophagus (BE). Gastric surgery patients provide a good model for both significant pancreatic-biliary reflux and marked gastric acid inhibition. We assessed the risk of EE and BE after distal gastrectomy in a case-controlled study.

MATERIAL AND METHODS

One hundred and sixty patients (121 men, 39 women; median age 68 years; range 32-86 years) with distal gastrectomies (Billroth-I) and 160 sex- and age-matched controls with intact stomachs were enrolled. The presence of EE and BE were diagnosed based on the Los Angeles Classification and the Prague C & M Criteria, respectively. A conditional logistic regression model with adjustments for potential confounding factors was used to assess the associations.

RESULTS

According to the multivariate analyses, patients with distal gastrectomies tended to have inverse associations with the risks of EE and BE, and the inverse association with the risk of BE reached a significant level.

CONCLUSIONS

Distal gastrectomy is not a risk factor for the development of EE and BE. This lack of a positive association between distal gastrectomy and EE and BE may suggest that pancreatic-biliary reflux with a limited amount of acid is not sufficient to damage the esophageal mucosa.

Effects of ecabet sodium on acute mixed reflux esophagitis in rats

OBJECTIVE

Ecabet sodium (ENa) is a drug that repairs epithelial cells in the digestive tract via selective adhesion to damaged tissue. While the principal cause of reflux esophagitis is gastroesophageal acid reflux, the involvement of duodenal juice has also been identified as an important factor. This study aimed to explore the effect of ENa in an acute mixed reflux esophagitis (AMRE) rat model.

MATERIAL AND METHODS

Eight-week-old male Wistar rats were used to prepare an AMRE model. There were four experimental groups: Group A (sham-operated rats), Group B (AMRE rats), Group C (AMRE rats dosed with ENa at 10 mg/kg), and Group D (AMRE rats dosed with ENa at 30 mg/kg). All rats were assessed for incidence of macroscopic esophageal lesions, esophagitis index, and pathological findings. Amylase activity, bile acid concentration in the digestive fluid retained in the esophagogastric lumen and ENa concentration in the esophageal mucosa were determined.

RESULTS

The incidence of esophagitis was 0% for Group A, 100% for Group B, 40% for Group C, and 20% for Group D. It was significantly lower for Groups C and D relative to Group B. The median esophagitis index was 0 for Group A, 58.2 for Group B, 0 for Group C, and 0 for Group D, and it was significantly lower for Groups C and D relative to Group B. The histological severity grade of esophagitis in Groups C and D was significantly less than that in Group B.

CONCLUSION

Treatment with ENa inhibited the development of AMRE in rats.

Gallstones increase the prevalence of Barrett's esophagus

PURPOSE

Bile and acid exposures are thought to be major risk factors for Barrett's esophagus in Western countries. The association of gallstones with Barrett's esophagus has not been fully evaluated. The present study was designed as a case-control study for determining the possible factors associated with endoscopically suspected esophageal metaplasia (ESEM), defined as an endoscopic finding suggestive of Barrett's esophagus, in Japanese patients.

METHODS

A total of 528 patients with ESEM were allocated to the case group, while 528 age- and gender-matched patients without ESEM were allocated to the control group. Findings on esophagogastroduodenoscopy and clinical background factors were compared using a multivariate logistic regression model.

RESULTS

The presence of gallstones and hiatus hernia and the severity of gastric mucosal atrophy were independently associated with the presence of ESEM [odds ratio (OR) 1.67, 95% confidence interval (CI) 1.03-2.69; OR 2.75, 95% CI 1.75-4.33; OR 1.25, 95% CI 1.01-5.6, respectively]. Compared with subjects with neither gastric corpus atrophy nor gallstones, although subjects with gallstones alone were not associated with the presence of ESEM (OR 1.59, 95% CI 0.87-2.92), having both gastric corpus atrophy and gallstones was strongly associated with the presence of ESEM (OR 2.94, 95% CI 1.40-6.17).

CONCLUSIONS

The presence of gallstones was independently associated with the presence of ESEM in the Japanese outpatient population, suggesting a causal association of distal esophageal bile exposure with the development of ESEM. Further studies are needed to confirm our findings in cases with histologically confirmed Barrett's esophagus.

Cryotherapy in the management of esophageal dysplasia and malignancy

Accumulating evidence highlights the promising results seen with endoscopic spray cryotherapy in the treatment of dysplasia associated with Barrett esophagus and esophageal carcinoma. Published studies show that the success of spray cryotherapy to eradicate Barrett high-grade dysplasia is comparable to that for other therapies, with a favourable safety profile and high levels of patient comfort. For patients with untreatable esophageal cancer, spray cryotherapy offers a therapeutic option with the potential for complete eradication in early-stage disease and palliation in advanced cases. The mechanism of tissue injury in cryotherapy is unique, with direct cytotoxic effects and ischemic effects from vascular injury. Increased tumor cell death through induction of apoptosis and immunologic effects require further study.

Pediatric gastroesophageal reflux clinical practice guidelines: joint recommendations of the North American Society for Pediatric Gastroenterology, Hepatology, and Nutrition (NASPGHAN) and the European Society for Pediatric Gastroenterology, Hepatology, and Nutrition (ESPGHAN)

OBJECTIVE

To develop a North American Society for Pediatric Gastroenterology, Hepatology, and Nutrition (NASPGHAN) and European Society for Pediatric Gastroenterology, Hepatology, and Nutrition (ESPGHAN) international consensus on the diagnosis and management of gastroesophageal reflux and gastroesophageal reflux disease in the pediatric population.

METHODS

An international panel of 9 pediatric gastroenterologists and 2 epidemiologists were selected by both societies, which developed these guidelines based on the Delphi principle. Statements were based on systematic literature searches using the best-available evidence from PubMed, Cumulative Index to Nursing and Allied Health Literature, and bibliographies. The committee convened in face-to-face meetings 3 times. Consensus was achieved for all recommendations through nominal group technique, a structured, quantitative method. Articles were evaluated using the Oxford Centre for Evidence-based Medicine Levels of Evidence. Using the Oxford Grades of Recommendation, the quality of evidence of each of the recommendations made by the committee was determined and is summarized in appendices.

RESULTS

More than 600 articles were reviewed for this work. The document provides evidence-based guidelines for the diagnosis and management of gastroesophageal reflux and gastroesophageal reflux disease in the pediatric population.

CONCLUSIONS

This document is intended to be used in daily practice for the development of future clinical practice guidelines and as a basis for clinical trials.

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

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

Comparison of gastroesophageal reflux in 100 patients with or without prior gastroesophageal surgery

BACKGROUND AND PURPOSE

The role of duodenogastroesophageal reflux (DGER) in gastroesophageal reflux disease (GERD) remains controversial. Few studies of reflux have compared patients with an intact stomach to those without intact stomach after gastroesophageal surgery. This study aimed to investigate differences of the refluxate between patients with and without prior gastroesophageal surgery and to assess the role of DGER in GERD.

METHODS

One hundred patients (34% with reflux symptoms) were divided into four groups: 23 with an intact stomach, and 27, 42, and 8 with esophagectomy followed by gastric tube reconstruction, distal gastrectomy, and total gastrectomy, respectively. Reflux symptoms were evaluated, and endoscopy and simultaneous 24-h monitoring of esophageal pH and bilirubin were performed.

RESULTS

Of 44 patients with increased DGER but without increased acid reflux, three had severe reflux esophagitis and seven had Barrett's esophagus. DGER was most frequent under weakly acidic conditions in the intact stomach, esophagectomy, and distal gastrectomy groups. Pure acid reflux and DGER at any pH were elevated in GERD patients with an intact stomach, while weakly acidic and alkaline DGER were elevated in GERD patients after gastrectomy. Esophagectomy patients had reflux with the combined characteristics of those in the intact stomach and gastrectomy groups. Weakly acidic or alkaline DGER was correlated with symptoms and esophageal mucosal changes in gastrectomy patients.

CONCLUSION

The refluxate causing GERD differed between patients with and without prior gastroesophageal surgery. Weakly acidic or alkaline DGER may cause both symptoms and esophageal mucosal damage.

Current pharmacological management of gastro-esophageal reflux in children: an evidence-based systematic review

Gastro-esophageal reflux (GER) is a common phenomenon, characterized by the regurgitation of the gastric contents into the esophagus. Gastro-esophageal reflux disease (GERD) is the term applied when GER is associated with sequelae or faltering growth. The main aims of treatment are to alleviate symptoms, promote normal growth, and prevent complications. Medical treatments for children include (i) altering the viscosity of the feeds with alginates; (ii) altering the gastric pH with antacids, histamine H(2) receptor antagonists, and proton pump inhibitors; and (iii) altering the motility of the gut with prokinetics, such as metoclopramide and domperidone. Our aim was to systematically review the evidence base for the medical treatment of gastro-oesophageal reflux in children. We searched PubMed, AdisOnline, MEDLINE, and EMBASE, and then manually searched reviews from the past 5 years using the key words 'gastro-esophageal' (or 'gastroesophageal'), 'reflux', 'esophagitis', and 'child$' (or 'infant') and 'drug$' or 'therapy'. Articles included were in English and had an abstract. We used the levels of evidence adopted by the Centre for Evidence-Based Medicine in Oxford to assess the studies for all reported outcomes that were meaningful to clinicians making decisions about treatment. This included the impact of clinical symptoms, pH study profile, and esophageal appearance at endoscopy. Five hundred and eight articles were reviewed, of which 56 papers were original, relevant clinical trials. These were assessed further. Many of the studies considered had significant methodological flaws, although based on available evidence the following statements can be made. For infant GERD, ranitidine and omeprazole and probably lansoprazole are safe and effective medications, which promote symptomatic relief, and endoscopic and histological healing of esophagitis. Gaviscon(R) Infant sachets are safe and can improve symptoms of reflux. There is less evidence to support the use of domperidone or metoclopramide. More evidence is needed before other anti-reflux medications can be recommended. For older children, acid suppression is the mainstay of treatment. The largest evidence base supports the early use of H(2) receptor antagonists or proton pump inhibitors.

[Gastro-esophageal reflux through gastric antisecretory drugs]

During the 20th century, gastro-esophageal reflux moved from the status of a rare and severe disease to that of a frequent disease occurring mostly, in the absence of any significant lesions. Proton pump inhibitors (PPIs) are the mainstay of its therapy and are prescribed mainly in an empirical way. Extradigestive manifestations require more accurate diagnostic tests and therapeutic management. The modalities of prescription of the PPIs quickly progressed toward the on-demand therapy and over-the-counter PPIs should become widespread. The relative failures of PPIs led to a profusion of new antisecretory agents but clinical improvements are presently disappointing and the rationale of this escalation is questionable. The concept of non acid gastro-esophageal reflux opens more innovative diagnostic and therapeutic perspectives which, however, must be validated. In this respect, endoscopic treatment needs more reliable techniques and more rigorous trials. Gastro-esophageal reflux refractory to PPIs corresponds mainly to functional esophageal disorders that need diagnostic and therapeutic improvements. Barrett's esophagus constitutes a major challenge for the next few years. Its screening and its prevention seem, for the moment, inaccessible. Its survey and the prevention of its complications should benefit from progress of diagnostic and interventional endoscopy.

Utility of non-endoscopic investigations in the practical management of oesophageal disorders

The current available methods for diagnosis of GORD are symptom questionnaires, catheter and wireless pH-metry, impedance-pH monitoring and Bilitec(@). Osophageal pH monitoring allows both quantitative analysis of acid reflux and assessment of reflux-symptom association. Impedance-pH monitoring detects all types of reflux (acid and non-acid) and allows assessment of proximal extent of reflux, a relevant parameter for understanding symptoms perception and extraoesophageal symptoms. Bilitec provides a quantitative assessment of duodeno-gastro-oesophageal reflux. Oesophageal motor abnormalities have been associated with GORD symptoms as well as chest pain and dysphagia. High-resolution manometry contributed to re-classify oesphageal motor disorders. However, barium swallows are still essential for evaluation of oesophageal anatomy and combined oesophageal manometry-impedance can assess oesophageal motility and bolus transit simultaneously in a non-radiological way. Still in experimental phase, high-frequency ultrasound allows monitoring of the oesophageal wall thickness and exaggerated longitudinal muscle contraction that might be associated to chest pain and dysphagia. This chapter provides a critical evaluation of the clinical application of these techniques.

The influence of symptom type and duration on the fate of the metaplastic columnar-lined Barrett's oesophagus

BACKGROUND

Prolonged gastro-oesophageal reflux resulting in columnar metaplasia of the oesophagus is the main risk factor for oesophageal adenocarcinoma.

AIM

To examine the duration of symptoms and associations of different symptoms with the development of columnar-lined oesophagus, dysplasia and adenocarcinoma.

METHODS

UK multicentre cohort study of patients with columnar-lined oesophagus whose date of symptom onset (1082 patients) and/or types of symptoms reported (1681 patients) were documented. Follow-up was examined by analysis of histological reports from the registering centers.

RESULTS

Symptoms of dysphagia/odynophagia and nausea/vomiting were associated with development of dysplasia. High-grade dysplasia and adenocarcinoma were associated with dysphagia/odynophagia and weight loss. Median duration from symptom onset to detection of columnar-lined oesophagus without intestinal metaplasia: 2.6 years, columnar-lined oesophagus with intestinal metaplasia: 5.0 years, indefinite changes for dysplasia: 19.3 years and low-grade dysplasia: 30.0 years. One tenth of patients had developed high-grade dysplasia at 9.6 years and one tenth had developed adenocarcinoma at 13.8 years from symptom onset.

CONCLUSIONS

In patients with columnar-lined oesophagus, symptoms of dysphagia/odynophagia and nausea/vomiting were associated with a higher risk of development of dysplasia and adenocarcinoma. There is a trend for longer duration of symptoms to the detection of dysplasia.

Esophageal cell proliferation in gastroesophageal reflux disease: Clinical-morphological data before and after pantoprazole

AIM: To evaluate esophageal mucosal defense mechanisms at an epithelial level to establish if pantoprazole treatment can induce ultrastructural healing and improvement in the proliferation activity of the esophageal epithelium in gastroesophageal reflux disease (GERD).

METHODS: This was a single-blinded study for pH-monitoring, and histological, ultrastructural and MIB1 immunostaining evaluation. Fifty eight patients with GERD were enrolled and underwent 24 h pH-monitoring and endoscopy. Patients were treated for 12 and 24 mo with pantoprazole. Esophageal specimens were taken for histological and ultrastructural evaluation, before and after the treatment.

RESULTS: With transmission electron microscopy, all patients with GERD showed ultrastructural signs of damage with dilation of intercellular spaces (DIS). After 3 mo of therapy the mean DIS values showed a significant reduction and the mean MIB1-LI values of GERD showed an increase in cell proliferation. A further 3 mo of therapy significantly increased cell proliferation only in the erosive esophagitis (ERD) group.

CONCLUSION: Three months of pantoprazole therapy induced ultrastructural healing of mucosal damage in 89% and 93% of ERD and non-erosion patients, respectively. Moreover, long-term pantoprazole treatment may be helpful in increasing the capability for esophageal cell proliferation in GERD, particularly in ERD patients.

Ambulatory monitoring of GERD: current technology

Various techniques have been devised to diagnose, characterize, and classify gastroesophageal reflux (GER). Stationary techniques, such as fluoroscopy and scintigraphy, provide interesting anatomic and functional information related to GER but are not sensitive enough and are usually performed in nonphysiologic conditions. Ambulatory techniques for GER monitoring have been developed and used since 1974. The current available techniques include catheter and wireless pH-metry, Bilitec, and impedance-pH monitoring. Prolonged wireless pH monitoring can be useful to evaluate patients off and on proton pump inhibitor (PPI) treatment. Impedance-pH monitoring is being used increasingly in patients who have persistent symptoms on PPI therapy because it can establish an association between symptoms and weakly acidic or nonacid reflux. Bilitec is performed in patients suspected to have increased duodenogastroesophageal reflux (DGER). This article discusses the technical details, clinical indications, and applications of these diagnostic techniques.

NERD, GERD, and Barrett's esophagus: role of acid and non-acid reflux revisited with combined pH-impedance monitoring

INTRODUCTION

Gastroesophageal reflux is the most important factor in the development of Barrett's metaplasia. The effect of acid reflux is commonly accepted today, but there is controversy about the role of non-acid reflux. With introduction of combined esophageal pH-impedance monitoring, a precise diagnostic test for acid and non-acid reflux is now available.

METHODS

Ninety two consecutive patients (33 women) off acid-suppressive therapy underwent diagnostic work-up for suspected gastroesophageal reflux disease including upper-GI endoscopy, esophageal manometry, barium swallow, and combined esophageal pH-impedance monitoring. Patients were subdivided into three groups according to symptoms and endoscopic appearance: typical symptoms without esophagitis (n = 28; NERD); erosive esophagitis (n = 52, ERD), and patients with intestinal metaplasia (n = 12, BE).

RESULTS

Pathologic acid reflux during pH-metry was found in 35.7%, 63.5%, and 75.0% for NERD, ERD, and BE patients, respectively (P = 0.022). Likewise, the percentage of time pH < 4 rose significantly during upright, supine, and total phases. In contrast, combined pH-impedance monitoring showed no significant difference between groups for the number of acid reflux events and for percentage of acid bolus reflux time. However, BE patients had significantly more non-acid reflux events and a higher percentage of non-acid bolus reflux time during the supine (P = 0.043, P = 0.020, respectively), but not during the upright phase (P = 0.740, P = 0.730, respectively).

CONCLUSION

Patients with BE are exposed to increased supine non-acid reflux and to increased acid reflux during upright and supine phases. This observation supports the concept that nocturnal non-acid reflux may play a role in the pathogenesis of BE.

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.

Treatment modality and risk of development of dysplasia and adenocarcinoma in columnar-lined esophagus

Columnar metaplasia is the precursor lesion for esophageal adenocarcinoma, resulting from prolonged gastroesophageal reflux. The influence of the efficacy of reflux control on the development of neoplastic change in columnar-lined esophagus is not established. This study compares the rate of development of dysplasia and adenocarcinoma in patients with columnar metaplasia of the esophagus between patients treated pharmacologically and those treated with antireflux surgery. This study is a retrospective review of a cohort of patients enrolled in a multicenter national registry involving 738 patients from seven UK centers. Forty-one were treated with antireflux surgery, 42 with H2 receptor antagonist, 532 with proton pump inhibitor, and 114 with a combination of these medications. Nine had none of these medications or surgery. Total follow-up was 3697 years. Mean age and follow-up for patients treated medically were 61.6 and 4.96 years and surgically were 50.5 and 6.19 years, respectively. No patient in the surgical group developed high-grade dysplasia (HGD) or adenocarcinoma. Twenty patients treated medically developed adenocarcinoma and 10 developed HGD. Hazards ratio comparing pharmacological to surgical therapy for development of all grades of dysplasia and adenocarcinoma 1.77 (P = 0.272). Log rank test comparing antireflux surgery to pharmacological therapy for development of HGD or adenocarcinoma P = 0.1287 and for adenocarcinoma P = 0.2125. Although there was a trend towards greater efficacy of antireflux surgery over pharmacological therapy in reducing the development of dysplasia and adenocarcinoma, this did not reach statistical significance.

Diagnostic options for patients with refractory GERD

Patients with refractory gastroesophageal reflux disease (GERD) are those who have persistent symptoms while being treated with proton pump inhibitors (PPIs). One third of GERD patients requiring a daily PPI are estimated to eventually experience treatment failure. These patients are usually referred for further investigation to confirm the presence of GERD or to identify other entities as the cause of symptoms. Tools that can be used in this diagnostic process include upper gastrointestinal endoscopy with analysis of esophageal biopsies, esophageal pH monitoring, impedance-pH monitoring, and esophageal bilirubin monitoring. The conventional diagnostic approach includes upper gastrointestinal endoscopy and ambulatory pH monitoring while receiving PPI therapy. New diagnostic techniques that may be useful with refractory GERD include impedance-pH monitoring, which is very sensitive in detecting persistent weakly acidic reflux, and bilirubin monitoring, which detects increased esophageal exposure to bile. Gastric pH monitoring should be reserved for patients in whom PPI resistance is suspected.

Proton pump inhibitor influence on reflux in Barrett's oesophagus

OBJECTIVES

It is important to identify factors responsible for the development of Barrett's oesophagus (BO). The effect of proton pump inhibitors (PPIs) on oesophageal clearance of both acid and alkaline reflux in these patients is uncertain and studies comparing BO patients and healthy controls (HCs) have not been performed earlier.

METHODS

Two groups of patients were studied: 18 HCs and 12 BO patients. Oesophageal motility, acid reflux and duodenogastro-oesophageal reflux (DGOR) were measured using a three-pressure transducer catheter with an antimony pH tip, connected to a sodium ion selective electrode. All patients were studied both on and off PPIs.

RESULTS

Without PPI therapy, BO patients had significantly more upright and supine acid reflux and upright DGOR compared with HCs. During acid reflux, HC demonstrated more peristalsis than BO [HC, % peristalsis=64 (9), BO=53 (8), P<0.01], but this was not seen during DGOR. [HC, % peristalsis=68 (14), BO=56 (11)]. In Barrett's patients, DGOR was significantly reduced with PPIs [off PPI, % upright DGOR=61 (17), on PPIs=19 (15), P<0.01], and no oesophageal motility differences were seen compared with results without PPIs.

CONCLUSION

HCs demonstrate better oesophageal motility compared with BO patients to prevent acid and alkaline reflux. When acid reflux occurred, HCs had better coordinated motility to remove it. This increased coordination did not occur during DGOR, suggesting different stimulation mechanisms. PPI reduced DGOR in BO patients, without any change in oesophageal motility.

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.

New developments in gastroesophageal reflux disease diagnosis and therapy

PURPOSE OF REVIEW

Gastroesophageal reflux disease is a highly prevalent chronic condition in Western populations. It has a profound effect on our society in terms of economic cost and quality of life. There have been major advances in understanding of disease pathogenesis over the last few years which are summarized in this article.

RECENT FINDINGS

With improved understanding of gastroesophageal reflux disease, newer developments in diagnostic techniques have evolved. The proton pump inhibitor test has been formally described as one of the initial diagnostic tests. Other new tests include multiple channel impedance monitoring, bilirubin reflux monitoring, Barostat measurements and intraluminal ultrasounds which, along with other newer technologies, are described in this review.

SUMMARY

The mechanisms involved in the pathogenesis of gastroesophageal reflux disease are complex and multifactorial. The lower esophageal sphincter pressure, the motility of the esophageal body and the stomach, the composition of the reflux material and the sensitivity or resistance of the esophageal mucosa to the reflux material are important factors involved in the pathogenesis of disease-related symptoms and lesions. Based on our improving understanding, novel diagnostic tools are available to improve investigation of the disease.

Barrett's esophagus: pathogenesis, treatment, and prevention

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

Development of Barrett's Esophagus Soon after Total Gastrectomy

The role of duodenal reflux and the time required for the development of Barrett's esophagus has remained controversial. We report a case of Barrett's esophagus that developed 6 months after total gastrectomy. A 76-year-old man diagnosed with gastric adenocarcinoma underwent a total gastrectomy and a Rouxen-Y esophagojejunostomy. The gastroesophageal junction in the resected specimen was both grossly and microscopically normal at the time of the operation. A routine follow-up endoscopic examination performed 6 months later revealed a tongue-like projection of redcolored columnar tissue. No reflux symptoms (heartburn or acid regurgitation) had been present during the intervening 6 months. A biopsy specimen from the esophagus showed intestinal-type metaplasia of the columnar epithelium. This case supports the development of Barrett's esophagus solely from duodenal reflux and after a relatively short time in this clinical setting.

The effect of oral administration of ursodeoxycholic acid and high-dose proton pump inhibitors on the histology of Barrett's esophagus

Bile acids may play a role in the pathogenesis of Barrett's esophagus (BE). Bile composition can be influenced by oral administration of ursodeoxycholic acid (UDCA). We prospectively investigated the effect of proton pump inhibitors (PPI) supplemented with UDCA in vivo in patients with BE. Patients with no or low-grade dysplasia who were clinically asymptomatic on PPI were eligible for the study. In order to exclude the effects of acid reflux, all patients were initially treated with 40 mg esomeprazole (ESO) twice daily for 6 months and continued on this dose till the end of the study (t = 12 months). During a period of 6 months (t = 6 month - t = 12 month) patients were treated with oral UDCA (600 mg twice daily). Patients underwent endoscopy at t = 0 months, t = 6 months and t = 12 months with multiple biopsies of the distal and proximal BE segment, normal squamous and gastric cardia. In addition, pH was measured at t = 0 months and t = 6 months using a BRAVO wireless pH capsule. Bile was sampled at the beginning of the UDCA treatment and 6 months later (t = 6 month and t = 12 month). All biopsies were reviewed for the extent of metaplasia, dysplasia, and acute and chronic inflammation. In addition, proliferation (Ki67), differentiation (villin, cytokeratins 7 and 20) and inflammation (COX-2) were investigated by immunohistochemistry (IHC). Nine patients (mean age 60 years, median BE length 7 cm) were included, of whom six had no dysplasia and three had low-grade dysplasia. pH measurements revealed a normal acid exposure in most patients at t = 0 and t = 6 months. In addition, bile composition analysis demonstrated the efficacy of UDCA. Combining the results of both phases of the study, no significant changes were seen in any of the histological or IHC parameters. Differentiation and proliferation parameters showed no significant changes. In this study, in BE patients who were clinically asymptomatic on PPI, increasing the PPI dose to the maximum for 6 months followed by the addition of UDCA for 6 months did not result in significant histological or IHC changes in their BE.

pH Testing: the basics

Esophageal pH testing, first described more than 3 decades ago, has become incorporated in the diagnostic armamentarium of most gastroenterologists. Using commercially available sophisticated equipment and software, the procedure is easy to perform and the analysis of the signals is automated. Nevertheless, users of esophageal pH testing must remain aware of the technical pitfalls that may stand in the way of the acquisition of meaningful results. Esophageal pH monitoring provides quantitative information about the exposure of the distal esophagus to acid. The technique makes it also possible, however, to quantify the correlation between symptom episodes and reflux events. In clinical practice, the latter is often more relevant than information on esophageal acid exposure.

Effect of cholecystectomy on gastric and esophageal bile reflux in patients with upper gastrointestinal symptoms

Epidemiologic data have shown that cholecystectomy is associated with a moderately increased risk of esophageal adenocarcinoma. The study objective was to evaluate the role of refluxed bile. A total of 696 patients with upper gastrointestinal symptoms were included in the study, of whom 55 had a history of cholecystectomy (CHE). Bilirubin exposure was measured in percent time above absorbance 0.25 in the stomach and above 0.14 in the esophagus. Total gastric and esophageal bilirubin exposure was similar in both groups. Supine gastric bile reflux was slightly increased after cholecystectomy (30.6 +/- 30.2 vs. CHE: 37.1 +/- 29.5, P < 0.05). In patients with erosive esophagitis or Barrett's esophagus, there were differences in total gastric exposure (24.3 +/- 22.6 vs. CHE: 36.7 +/- 26.8, P < 0.05) but not in esophageal exposure. Cholecystectomy slightly augments bile reflux into the stomach without detectable differences in the esophagus. Therefore, increased esophageal bile reflux following cholecystectomy as a potential cause for the associated cancer risk could not be substantiated.

High serum bile acids cause hyperthyroidism and goiter

BACKGROUND/AIMS

In the duodenal content reflux model of rats, we noted an elevation of serum bile acid and swelling of the thyroid gland. This study was designed to elucidate whether bile acids (BAs) also enhance thyroid function.

METHODS

In varying lengths of period after esophago-jejunostomy without gastrectomy, which causes duodenal content reflux, rats were sacrificed and blood samples were taken from the heart for analyses of BAs and triiodothyronine (T3), thyroxine (T4), free T3 (fT3), free T4 (fT4), and thyroid-stimulating hormone (TSH) in the serum.

RESULTS

Macroscopically, at 10 and 30 weeks after operation, thyroid glands in the reflux model showed a symmetric enlargement because of the presence of diffuse hypertrophy of the thyroid follicular epithelium. At both time points, no significant differences were detected in T3, T4, fT3, and fT4 levels between the reflux model and the control group, whereas, at 10 weeks after operation, the animals with the reflux showed significantly lower serum TSH levels and greater thyroid weight than those in the control group. An inverse correlation between serum BAs and TSH levels was noted in the reflux model but not in the control group. Microscopically, thyroid follicles were greater in size and number, with paler colloids in the reflux model than the control group.

CONCLUSIONS

The present results suggest that high serum BAs cause hyperplasia of the thyroid follicles and the reduction of TSH. The effects of BAs on thyroid hormones, thus, include the induction of overall hyperthyroidism. Therefore, the strict monitoring of serum TSH levels is of vital importance if BAs are used for the treatment of obesity.