Mixed reflux of gastric and duodenal juices is more harmful to the esophagus than gastric juice alone. The need for surgical therapy re-emphasized

The impact of laparoscopic anti-reflux surgery in patients with Barrett's esophagus

BACKGROUND

Barrett's esophagus (BE) is a major risk factor for esophageal adenocarcinoma. It is believed that BE is caused by chronic gastro-esophageal reflux disease (GERD). Laparoscopic anti-reflux surgery (LARS) restores the competency of the cardia and may thereby change the natural course of BE. We studied the impact of LARS on the histological profile of BE and on the control of GERD.

METHODS

We identified all patients with BE who underwent LARS from 1994 to 2007 and contacted them to assess post-operative GERD symptoms via questionnaire. Endoscopy findings, histology, 24 hour pH monitoring, and manometry were also collected using our prospectively maintained database. Histological regression was defined as either loss of dysplasia or disappearance of BE.

RESULTS

Two hundred and fifteen patients met the initial inclusion criteria; in 82 of them histology from post-operative endoscopy was available for review. Endoscopy was performed a median of 8 years (range, 1-16 years) after surgery. Regression of BE occurred in 18 (22%) patients while in 6 (7%) BE progressed to dysplasia or cancer. Thirty-six (43%) patients underwent pre- and post-operative manometry. The median lower esophageal sphincter pressure increased from 9 to 17 mmHg in these patients. Thirty-four (41%) patients underwent pre- and post-operative pH studies. The median DeMeester score decreased from 54 to 9. Sixty-seven (82%) of 82 patients completed the post-operative questionnaire; 86% of these patients reported improvement in heartburn and regurgitation.

CONCLUSIONS

LARS was associated with both physiologic and symptomatic control of GERD in patients with BE. LARS resulted in regression of BE in 22% of patients and progression in 7%. Thus, continued surveillance of Barrett's is needed after LARS.

Effects of bile acids on cyclooxygenase-2 expression in a rat model of duodenoesophageal anastomosis

AIM

To examine the expression of cyclooxygenase-2 (COX-2) and prostaglandin E2 (PGE2) in rat esophageal lesions induced by reflux of duodenal contents.

METHODS

Thirty 8-week-old male Wistar rats were exposed to duodenal content esophageal reflux. All animals underwent an esophagoduodenal anastomosis (EDA) with total gastrectomy to elicit chronic esophagitis. In ten rats sham operations with only a midline laparotomy were performed (Control). The rats were sacrificed at the 40(th) week, their esophagi were taken for hematoxylin and eosin staining and for examination of expression of COX2, PGE2, and proliferating cell nuclear antigen (PCNA), and total bile acids in the esophageal lumen was measured.

RESULTS

After 40 wk of reflux, columnar dysplasia, squamous cell carcinoma and adenocarcinoma were observed. Total bile acids in the esophageal lumen were significantly increased in the EDA group compared with the sham operated rats. PCNA labelling index and esophageal tissue PGE2 levels were higher in dysplastic and cancer tissues than in control tissues. Overexpression of COX2 was observed in dysplastic and cancer tissues.

CONCLUSION

Reflux of duodenal contents induces COX2 expression and increases prostaglandin synthesis in dysplastic and cancer tissues. This result suggests a possible mechanism by which bile acids promote esophageal cancer.

Impact of inflammation-metaplasia-adenocarcinoma sequence and inflammatory microenvironment in esophageal carcinogenesis using surgical rat models

BACKGROUND AND AIMS

Chronic inflammation has been demonstrated to correlate with tumor onset and progression. Tumor-associated macrophages (TAMs) play an important role in inflammatory tumor microenvironment. We hypothesized that an inflammatory microenvironment around TAMs may promote the development of esophageal carcinomas when induced by duodenal content reflux without carcinogens.

ANIMALS AND METHODS

A total gastrectomy followed by esophagojejunostomy was performed on rats in order to induce chronic duodenal content reflux esophagitis. The animals were sacrificed sequentially, at the 20th, 30th, 40th and 50th week after surgery, and their esophagi were examined. The primary antibodies against CD68, CD163, pStat3 and Foxp3 were used. Expression and localization of infiltrated cells was assessed by immunohistochemical analysis.

RESULTS

At 20-weeks' post-surgery, squamous proliferative hyperplasia (PHP) and Barrett's metaplasia (BM) were observed. Adenocarcinoma (ADC) associated with BM, and squamous cell carcinoma (SCC) were observed 30-50 weeks' post-surgery. Numerous CD68 and pStat3-positive cells were identified surrounding PHP and BM after 20 weeks, and around ADC and SCC after 30 weeks. Moderate infiltration of CD163-positive macrophages was seen with BM, ADC, and SCC after 30 weeks. However, very few Foxp3-positive cells were observed around ADC and SCC.

CONCLUSION

Macrophages infiltrate the esophagus and activate the pStat3 pathway in stromal cells and epithelium. M2 phenotype macrophages infiltrate following infiltration of M1 macrophage and contribute to tumor development through regulatory T cells (Tregs). The involvement of immune cells such as TAMs and Tregs in the inflammatory microenvironment promotes esophageal carcinogenesis.

Idiopathic pulmonary fibrosis and gastroesophageal reflux. Implications for treatment

BACKGROUND

Even though the pathogenesis of idiopathic pulmonary fibrosis (IPF) is unknown, there is mounting evidence that abnormal reflux (GERD) and aspiration of gastric contents may play a role in the pathogenesis of this disease.

AIMS

The aims of this study were to determine in patients with GERD and IPF: (a) the clinical presentation, (b) the esophageal function, and (c) the reflux profile.

METHODS

We compared the clinical presentation, the esophageal function (as defined by high-resolution manometry), and the reflux profile (by dual sensor pH monitoring) in 80 patients with GERD (group A) and in 22 patients with GERD and IPF (group B).

RESULTS

Heartburn was present in less than 60 % of patients with GERD and IPF. Lower esophageal sphincter pressure and peristalsis were normal in both groups, while the upper esophageal sphincter (UES) was more frequently hypotensive in IPF patients (p = 0.008). In patients with GERD and IPF, the proximal esophageal acid exposure was higher (p = 0.047) and the supine acid clearance was slower as compared with patients with GERD only (p < 0.001).

CONCLUSIONS

The results of this study show that in patients with GERD and IPF: (a) reflux is frequently silent, (b) with the exception of a weaker UES, the esophageal function is preserved, and (c) proximal reflux is more common, and in the supine position, it is coupled with a slower acid clearance. Because these factors predisposing IPF patients to the risk of aspiration, antireflux surgery should be considered early after the diagnosis of IPF and GERD is established.

Carcinogenesis of Barrett's esophagus: a review of the clinical literature

Barrett's esophagus (BE) is a premalignant condition of esophageal adenocarcinoma (EAC). Although the incidence of BE has risen rapidly in the West, it is rare in Asia despite a recent increase in the prevalence of gastroesophageal reflux disease. Controversies over the definition of BE are presented because most cases show short-segment BE, especially ultra-short BE, in Asia. Here we review possible risk factors for the development of EAC, particularly possible roles of ethnicity, specialized intestinal metaplasia (SIM), BE length, and environmental factors, such as Helicobacter pylori infection and obesity. Additionally, we summarize recent studies on the effect of chemoprevention including proton pump inhibitors, nonsteroidal anti-inflammatory drugs or aspirin in order to reduce the risk of neoplastic progression in BE patients. Although substantial knowledge of risk factors of dysplasia/EAC in BE is shown, the risk for neoplastic development may be influenced by geographic variation, study population, the presence or absence of SIM or dysplasia at baseline, and the small number of BE patients investigated. Recently, the efficiency of surveillance for BE patients has been discussed from the standpoint of cost-effectiveness. It may be too difficult to draw conclusions because no randomized clinical trials of BE surveillance have been performed.

The pulmonary side of reflux disease: from heartburn to lung fibrosis

INTRODUCTION

Gastroesophageal reflux disease (GERD) is the most prevalent gastrointestinal disorder in the USA. Heartburn is the symptom most commonly associated with this disease, and the highly commercialized medical treatment directed toward relief of this symptom represents a 10-billion-dollar-per-year industry.

DISCUSSION

Unfortunately, there is often little awareness that GERD can be potentially a lethal disease as it can cause esophageal cancer. Furthermore, there is even less awareness about the relationship between GERD and respiratory disorders with the potential for severe morbidity and even mortality.

Upper gastrointestinal cancer and reflux disease

There is a growing evidence that gastroesophageal reflux disease is related to several upper gastrointestinal cancers, mainly the esophageal adenocarcinoma and a certain type of gastric cardia adenocarcinoma. Currently, the incidence of gastroesophageal reflux disease is rapidly increasing in Korea. Therefore, there is a possibility of such increasing cancerous incidents, similar to the western worlds. In this article, the relationship between gastroesophageal reflux disease and several upper gastrointestinal cancers, the components of refluxate which has possible causal relationship with carcinogenesis, and the clinical implications of such relationship in the management of gastroesophageal reflux disease patients are discussed through the review of literature.

Differences in the Characteristics of Barrett's Esophagus and Barrett's Adenocarcinoma between the United States and Japan

In Europe and the United States, the incidence of esophageal adenocarcinoma has increased 6-fold in the last 25 years and currently accounts for more than 50% of all esophageal cancers. Barrett's esophagus is the source of Barrett's adenocarcinoma and is characterized by the replacement of squamous epithelium with columnar epithelium in the lower esophagus due to chronic gastroesophageal reflux disease (GERD). Even though the prevalence of GERD has recently been increasing in Japan as well as in Europe and the United States, the clinical situation of Barrett's esophagus and Barrett's adenocarcinoma differs from that in Western countries. In this paper, we focus on specific differences in the background factors and pathophysiology of these lesions.

Impact of minimally invasive surgery on the treatment of benign esophageal disorders

Thanks to the development of minimally invasive surgery, the last 20 years have witnessed a change in the treatment algorithm of benign esophageal disorders. Today a laparoscopic operation is the treatment of choice for esophageal achalasia and for most patients with gastroesophageal reflux disease. Because the pathogenesis of achalasia is unknown, treatment is palliative and aims to improve esophageal emptying by decreasing the functional obstruction at the level of the gastro-esophageal junction. The refinement of minimally invasive techniques accompanied by large, multiple randomized control trials with long-term outcome has allowed the laparoscopic Heller myotomy and partial fundoplication to become the treatment of choice for achalasia compared to endoscopic procedures, including endoscopic botulinum toxin injection and pneumatic dilatation. Patients with suspected gastroesophageal reflux need to undergo a thorough preoperative workup. After establishing diagnosis, treatment for gastroesophageal reflux should be individualized to patient characteristics and a decision about an operation made jointly between surgeon and patient. The indications for surgery have changed in the last twenty years. In the past, surgery was often considered for patients who did not respond well to acid reducing medications. Today, the best candidate for surgery is the patient who has excellent control of symptoms with proton pump inhibitors. The minimally invasive approach to antireflux surgery has allowed surgeons to control reflux in a safe manner, with excellent long term outcomes. Like achalasia and gastroesophageal reflux, the treatment of patients with paraesophageal hernias has also seen a major evolution. The laparoscopic approach has been shown to be safe, and durable, with good relief of symptoms over the long-term. The most significant controversy with laparoscopic paraesophageal hernia repair is the optimal crural repair. This manuscript reviews the evolution of these techniques.

The severity of duodeno-esophageal reflux influences the development of different histological types of esophageal cancer in a rat model

The mechanism through which each histological type of carcinoma arises from the esophageal mucosa remains unknown. This study was designed to investigate whether there is an association between the severity of duodeno-esophageal reflux and the histological type of esophageal cancer. A series of 120 male Fischer rats, weighing ∼180 g, were randomized to receive one of the following procedures: duodeno-forestomach reflux (DFR) with reduced exposure to duodenal contents, duodeno-esophageal reflux (DER) with increased exposure to duodenal contents and three control operations (DFR, DER control and sham). The reflux of bile was estimated with (99m)Tc-PMT scintigraphy. All animals were fed a standard diet without carcinogen. The esophageal mucosa was assessed 50 weeks after surgery for carcinoma. The median scanned fraction rate of duodeno-esophageal reflux was significantly lower for the rodents in the DFR group than those in the DER group. Five of 28 rodents in the DFR group and 17 of the 22 rodents in the DER group developed esophageal carcinoma. None of the controls developed carcinoma. The five rodents in the DFR group developed SCC. Of 22 esophageal carcinomas for the DER group, nine were SCC, 12 ADC and one was adenosquamous carcinoma. The fraction of esophageal SCC for the DFR group was significantly higher than that for the DER group, while the fraction of esophageal ADC for the DFR group was significantly lower than that for the DER group. These observations suggest that the severity of duodeno-esophageal reflux in rodents is related to the development of different histological types of esophageal carcinoma.

Reflux esophagitis after esophagectomy: impact of duodenogastroesophageal reflux

Reflux esophagitis (RE) is a known complication disturbing patients' quality of life after esophageal resection. It is generally recognized that bile reflux as well as acid reflux cause RE. However, the clinical influence of acid and bile reflux, and Helicobacter pylori (H. pylori) infection on RE in the cervical esophagus after esophagectomy is not yet clarified. Sixty patients who underwent cervical esophagogastrostomy following esophagectomy were enrolled in this study. They underwent examination for H. pylori infection, endoscopic examination, and continuous 24-hour pH and bilirubin monitoring, at 1 month after surgery. The influence of acid and/or bile reflux, H. pylori infection, and others on the development of RE were investigated. RE was observed in 19 patients (32%) at 1 month after esophagogastrostomy, mild RE in 16 (27%), and severe RE in 3 (5%). The percentage of time duration of both acid and bile reflux into the cervical esophagus was higher in patients with RE than in those without (P = 0.027, P < 0.001). A significant difference in %time pH < 4 acid reflux was found between mild RE and severe RE (P = 0.014), and a statistical difference in %time abs. > 0.14 between non-RE and mild RE (P = 0.017). Acid and/or bile reflux was observed in 31 patients (52%), acid-only reflux in 6 (10%), bile-only reflux in 15 (25%), and acid-and-bile reflux in 10 (17%). Severe RE was observed only in patients having acid-and-bile reflux. On the univariate analysis, no infection of H. pylori, acid reflux, and bile reflux were determined to be the influencing factors to RE among the clinical factors including age, gender, route of esophageal reconstruction, H. pylori infection, and acid-and-bile reflux. In the subanalysis using the logistic model, there were significant correlations between bile reflux and RE irrespective of the presence of H. pylori infection (P = 0.016, P = 0.007). On the other hand, there was a significant correlation between acid reflux and RE only in patients without H. pylori infection (P = 0.039). In the early period after esophagogastrostomy, bile reflux could cause RE irrespective of H. pylori infection, while acid reflex could cause RE only in patients without H. pylori infection. There is a possibility that bile reflux plays an important role in the development of RE after esophagectomy.

Inflammation and Barrett's carcinogenesis

Barrett's esophagus (BE) is one of the most common premalignant lesions in which normal squamous epithelium of the esophagus is replaced by metaplastic columnar epithelium. Esophageal adenocarcinoma (EA) develops through progression from BE to low- and high-grade dysplasia (LGD/HGD) and to adenocarcinoma. It is widely accepted that inflammation can increase cancer risk, promoting tumor progression. Therefore, inflammation is regarded as the seventh hallmark of cancer. In recent years, the inflammation-cancer connection of Barrett's carcinogenesis has been intensively studied, unraveling genetic abnormalities. Besides genetic alterations, inflammation is also epigenetically linked to loss of protein expression through transcriptional silencing via promoter methylation. Key mediators linking inflammation and Barrett's carcinogenesis include reactive oxygen species (ROS), NFκB, inflammatory cytokines, prostaglandins, and specific microRNAs (miRNAs). Therefore, the decipherment of molecular pathways that contain these and novel inflammatory key mediators is of major importance for diagnosis, therapy, and prognosis. The detailed elucidation of the signaling molecules involved in Barrett's carcinogenesis will be important for the development of pharmaceutical inhibitors. We herein give an overview of the current knowledge of the inflammation-mediated genetic and epigenetic alterations involved in Barrett's carcinogenesis. We highlight the role of oxidative stress and deregulated DNA damage checkpoints besides the NFκB pathway.

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

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

Regulation of the gene encoding the intestinal bile acid transporter ASBT by the caudal-type homeobox proteins CDX1 and CDX2

The apical sodium-dependent bile acid transporter (ASBT) is expressed abundantly in the ileum and mediates bile acid absorption across the apical membranes. Caudal-type homeobox proteins CDX1 and CDX2 are transcription factors that regulate genes involved in intestinal epithelial differentiation and proliferation. Aberrant expression of both ASBT and CDXs in Barrett's esophagus (BE) prompted us to study, whether the expression of the ASBT gene is regulated by CDXs. Short interfering RNA-mediated knockdown of CDXs resulted in reduced ASBT mRNA expression in intestinal cells. CDXs strongly induced the activity of the ASBT promoter in reporter assays in esophageal and intestinal cells. Nine CDX binding sites were predicted in silico within the ASBT promoter, and binding of CDXs to six of them was verified in vitro and within living cells by electrophoretic mobility shift assays and chromatin immunoprecipitation assays, respectively. RNAs were extracted from esophageal biopsies from 20 BE patients and analyzed by real-time PCR. Correlation with ASBT expression was found for CDX1, CDX2, and HNF-1α in BE biopsies. In conclusion, the human ASBT promoter is activated transcriptionally by CDX1 and CDX2. Our finding provides a possible explanation for the reported observation that ASBT is aberrantly expressed in esophageal metaplasia that also expresses CDX transcription factors.

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.

Barrett's esophagus and animal models

The following on Barrett's esophagus (BE) and animal models contains commentaries on the factors of BE carcinogenesis; a duodenoesophageal reflux model; translation of targeted therapies for esophageal adenocarcinoma; and novel target regimens selected through a proteomics screen.

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.

Inflammation-related carcinogenesis and prevention in esophageal adenocarcinoma using rat duodenoesophageal reflux models

Development from chronic inflammation to Barrett's adenocarcinoma is known as one of the inflammation-related carcinogenesis routes. Gastroesophageal reflux disease induces regurgitant esophagitis, and esophageal mucosa is usually regenerated by squamous epithelium, but sometimes and somewhere replaced with metaplastic columnar epithelium. Specialized columnar epithelium, so-called Barrett's epithelium (BE), is a risk factor for dysplasia and adenocarcinoma in esophagus. Several experiments using rodent model inducing duodenogastroesophageal reflux or duodenoesophageal reflux revealed that columnar epithelium, first emerging at the proliferative zone, progresses to dysplasia and finally adenocarcinoma, and exogenous carcinogen is not necessary for cancer development. It is demonstrated that duodenal juice rather than gastric juice is essential to develop esophageal adenocarcinoma in not only rodent experiments, but also clinical studies. Antireflux surgery and chemoprevention by proton pump inhibitors, nonsteroidal anti-inflammatory drugs, selective cyclooxygenase-2 inhibitors, green tea, retinoic acid and thioproline showed preventive effects on the development of Barrett's adenocarcinoma in rodent models, but it remains controversial whether antireflux surgery could regress BE and prevent esophageal cancer in clinical observation. The Chemoprevention for Barrett's Esophagus Trial (CBET), a phase IIb, multicenter, randomized, double-masked study using celecoxib in patients with Barrett's dysplasia failed to prove to prevent progression of dysplasia to cancer. The AspECT (Aspirin Esomeprazole Chemoprevention Trial), a large multicenter phase III randomized trial to evaluate the effects of esomeprazole and/or aspirin on the rate of progression to high-grade dysplasia or adenocarcinoma in patients with BE is now ongoing.

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

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

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.

Investigating the pathogenic role of PADI4 in oesophageal cancer

PADI4 post-translationally converts peptidylarginine to citrulline. PADI4 can disrupt the apoptotic process via the citrullination of histone H3 in the promoter of p53-target genes. The current study focused on PADI4 expression in various subtypes of oesophageal carcinoma (EC) by immunohistochemistry, western blotting and real time PCR. The study also investigated the effect of bile acid deoxycholate (DCA) on PADI4 expression in Eca-109 cells that originated from EC. Apoptosis and DCA-induced toxicity were analyzed by TUNEL, MTT assay and flow cytometry. Additionally, the present study investigated the correlation between single nucleotide polymorphism (SNP) in PADI4 gene and EC risk in Chinese population using Illumina GoldenGate assay. Compared with paraneoplastic tissues, the transcriptional and translational levels of PADI4 were significantly elevated in oesophageal squamous cell carcinoma (ESCC, n=9) and oesophageal adenocarcinoma (EAC, n=5) tissues. Immunolabeling detected expression of PADI4 in ESCC tissues (98.56%, n=139), EAC samples (87.5%, n=16) and oesophageal small cell undifferentiated carcinoma (91.7%, n=12) but not in normal tissues (0%, n=16). Furthermore, PADI4 levels is positively correlated with the pathological classification of ESCC (p=0.009). PADI4 expression levels were consistent with the number of apoptotic cells in the induced Eca-109 cells. rs10437048 [OR= 0.012831; 95% CI, 0.001746~0.094278; p=1.556×10^-12] were significantly associated with decreased risk of EC, whereas rs41265997 [OR=12.7; 95% CI, 0.857077~33.207214; p=3.896×10^-8] were significantly associated with increased risk of EC. rs41265997 in exon 3 of PADI4 gene is non-synonymous and converts ACG to ATG resulting in a threonine /methionine conversion at position 274 of the protein. Haplotypes GC that carries the variant alleles for rs2501796 and rs2477134 was significantly associated with increased risk of EC (frequency=0.085, p=0.0256, OR=2.7). The results suggest that PADI4 expression is related to the tumorigenic process of EC and the DCA-induced apoptosis. The PADI4 gene may be a valid EC susceptibility gene.

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.

Ambulatory esophageal pHmetry in healthy dogs with and without the influence of general anesthesia

This research aimed to determine the value of esophageal pH in awake and anesthetized dogs, to evaluate the esophageal pH value in awake dogs, in different body positions, as well as to study the occurrence of gastroesophageal reflux episodes in these positions. Thus, 40 healthy male and female adult dogs with mean body weight of 15.5 ± 4.6 kg were used. Esophageal pHmetry was conducted by inserting a catheter through the oropharynx in 30 dogs (stage 1) anesthetized with acepromazine, propofol and isoflurane, submitted to elective ovariosalpingohysterectomy. In addition, 8-h esophageal pHmetry was carried out transnasally in 10 awake dogs (stage 2), allowed to move and change body positions (lateral and sternal decubitus, and standing position), which were recorded. The mean esophageal pH value was lower (p < 0.01) in the anesthetized dogs (7.3 ± 0.82) than in the awake dogs (8.2 ± 0.3). Only four anesthetized dogs (13.33%) suffered reflux episodes. Reflux was not observed in the awake dogs and no esophageal pH differences were found between the body positions studied. Compared to the alert state, general anesthesia in dogs submitted to the previously mentioned anesthesia protocol causes esophageal pH reduction and predisposes to the occurrence of gastroesophageal reflux episodes. Transnasal pHmetry of 8 h in healthy awake dogs reveals that the esophageal pH value is alkaline and does not vary according to body position. In these animals, decubitus position is not a determining factor for reflux episodes to occur.

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.

Role of minimally invasive surgery in the modern treatment of Barrett's esophagus

Gastroesophageal reflux disease (GERD) is a highly prevalent disease. Population studies have demonstrated that a significant proportion of individuals weekly experience GERD symptoms. Barrett's esophagus (BE), defined by the presence of intestinal metaplasia (columnar epithelium with goblet cells), is considered a consequence of chronic reflux. This review defines the role of surgery in the modern treatment of BE, taking into consideration the pathophysiology of the disease and the new endoscopic procedures available at present.

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.

Long-term follow-up after anti-reflux surgery in patients with Barrett's esophagus

BACKGROUND

Factors associated with the risk of progression of Barrett's esophagus remain unclear, and the impact of therapy on this risk remains uncertain. The aim of this study was to assess patients followed long-term after anti-reflux surgery for Barrett's esophagus.

METHODS

A retrospective review was performed of all patients with Barrett's who underwent anti-reflux surgery from 1989 to 2009 and had ≥5 years of follow-up.

RESULTS

There were 303 patients and 75 had follow-up ≥5 years. Median follow-up time for the 75 patients was 8.9 years (range 5-18). Regression was seen in 31%. Progression occurred in 8%, and these patients were significantly more likely to have a failed fundoplication (67% vs. 16%, p = 0.0129). The rate of progression from non-dysplastic Barrett's to high-grade dysplasia or cancer was 0.8% per patient year, and was seven times higher in patients with a failed fundoplication.

CONCLUSION

Compared to the accepted rate of progression of non-dysplastic Barrett's to high-grade dysplasia or cancer of 1.0% per patient year, anti-reflux surgery reduces this rate during long-term follow-up. The rate of progression was significantly lower in patients with an intact compared to a disrupted fundoplication, further suggesting that anti-reflux surgery can alter the natural history of Barrett's esophagus.

Comparison of six immunohistochemical markers for the histologic diagnosis of neoplasia in Barrett's esophagus

In esophageal neoplasms, the histopathologic differentiation between Barrett's esophagus with or without intraepithelial neoplasia and adenocarcinoma is often challenging. Immunohistochemistry might help to differentiate between these lesions. The expression of CDX2, LI-cadherin, mucin 2 (MUC2), blood group 8 (BG8, Lewis(y)), claudin-2, and villin was investigated in normal gastroesophageal (n = 23) and in Barrett's (n = 17) mucosa, in low-grade (n = 12) and high-grade (n = 9) intraepithelial neoplasia (IEN) as well as in esophageal adenocarcinoma (n = 16), using immunohistochemistry. For CDX2 and LI-cadherin, the immunoreactivity score was highest in IEN while for MUC2, BG8, and villin, it dropped gradually from Barrett's via IEN to adenocarcinoma, and expression of Claudin-2 was only weak and focal in all lesions. The expression of MUC2 and LI-cadherin differed significantly between all examined lesions except between low-grade and high-grade IEN. MUC2 and LI-cadherin are useful immunohistochemical markers for the differentiation between normal glandular mucosa, Barrett's mucosa, IEN, and invasive carcinoma of the esophagus; however, none of the examined markers was helpful for the differentiation between low-grade and high-grade IEN.

Chemoprotective effects of curcumin in esophageal epithelial cells exposed to bile acids

AIM: To investigate the ability of curcumin to counteract the impact of bile acids on gene expression of esophageal epithelial cells.

METHODS: An esophageal epithelial cell line (HET-1A) was treated with curcumin in the presence of deoxycholic acid. Cell proliferation and viability assays were used to establish an appropriate dose range for curcumin. The combined and individual effects of curcumin and bile acid on cyclooxygenase-2 (COX-2) and superoxide dismutase (SOD-1 and SOD-2) gene expression were also assessed.

RESULTS: Curcumin in a dose range of 10-100 μmol/L displayed minimal inhibition of HET-1A cell viability. Deoxycholic acid at a concentration of 200 μmol/L caused a 2.4-fold increase in COX-2 gene expression compared to vehicle control. The increased expression of COX-2 induced by deoxycholic acid was partially reversed by the addition of curcumin, and curcumin reduced COX-2 expression 3.3- to 1.3-fold. HET-1A cells exposed to bile acid yielded reduced expression of SOD-1 and SOD-2 genes with the exception that high dose deoxycholic acid at 200 μmol/L led to a 3-fold increase in SOD-2 expression. The addition of curcumin treatment partially reversed the bile acid-induced reduction in SOD-1 expression at all concentrations of curcumin tested.

CONCLUSION: Curcumin reverses bile acid suppression of gene expression of SOD-1. Curcumin is also able to inhibit bile acid induction of COX-2 gene expression.

Pathophysiology and treatment of Barrett’s esophagus

Gastroesophageal reflux disease (GERD) affects an estimated 20% of the population in the United States. About 10%-15% of patients with GERD develop Barrett’s esophagus, which can progress to adenocarcinoma, currently the most prevalent type of esophageal cancer. The esophagus is normally lined by squamous mucosa, therefore, it is clear that for adenocarcinoma to develop, there must be a sequence of events that result in transformation of the normal squamous mucosa into columnar epithelium. This sequence begins with gastroesophageal reflux, and with continued injury metaplastic columnar epithelium develops. This article reviews the pathophysiology of Barrett’s esophagus and implications for its treatment. The effect of medical and surgical therapy of Barrett’s esophagus is compared.

The role of secondary bile acids in neoplastic development in the oesophagus

Bile acids have been demonstrated, through the use of animal models and clinical association studies, to play a role in neoplastic development in Barrett's metaplasia. How specific bile acids promote neoplasia is as yet unknown, as are the exact identities of the important bile acid subtypes. The combination of bile subtype with appropriate pH is critical, as pH alters bile acid activity enormously. Hence glycine-conjugated bile acids are involved in neoplastic development at acidic pH (pH ~4), and unconjugated bile acids are involved in neoplastic development at more neutral pH (~6). Bile acids (at the appropriate pH) are potent DNA-damaging agents, due to the induction of ROS (reactive oxygen species), which are mainly induced by bile-induced damage to mitochondrial membranes, allowing leakage of ROS into the cytosol. These ROS also induce pro-survival signalling pathways [e.g. via PKC (protein kinase C)-dependent NF-kappaB (nuclear factor kappaB) activity]. Interestingly, NOS (nitric oxide synthase), through induction of NO may exacerbate this NF-kappaB activity and form a positive-feedback loop to amplify the activation of NF-kappaB by deoxycholic acid in particular. This combination of induced DNA damage and cell survival by bile acids is of major importance in neoplasia. Antioxidants and the tertiary bile acid UDCA (ursodeoxycholic acid) can block bile-induced DNA damage and bile-induced NF-kappaB activity, and should be considered in chemopreventative strategies.

Evaluation of the heme oxygenase-1 expression in esophagitis and esophageal cancer induced by different reflux experimental models and diethylnitrosamine

PURPOSE: To study the expression of heme-oxygenase-1 (HO-1), an enzyme induced by oxidative stress, in specimens obtained from an experimental model in rats that evaluated the role of gastric and duodenal reflux in esophageal carcinogenesis. METHODS: Esophageal specimens embedded in paraffin obtained from different experimental groups of rats were used for immunohistochemistry analysis of HO-1 expression. The rats had been divided into the following groups and were killed after 22 weeks: (1) cardioplasty to induce acid reflux; (2) esophagoduodenal anastomosis to induce duodenal reflux; (3) no treatment; (4) cardioplasty + diethylnitrosamine (DEN); (5) esophagoduodenal anastomosis + DEN; and (6) DEN. The study sample comprised 3 specimens from each group with the most severe histopathological lesions found on each study branch. RESULTS: The expression of HO-1 was seen only in rat specimens submitted to esophagoduodenal anastomosis (Groups 2 and 5), and the analysis of mean fluorescence intensity revealed a significant increase of HO-1 expression (4.8 and 4.6 fold, respectively) when compared with the control group (Group 3) (p<0.05). The main target for HO-1 induction was the inflammatory cells inside the tumor or in subepithelial areas. Rats exposed to gastric reflux had no HO-1 expression. CONCLUSION: Reflux esophagitis induced by reflux of duodenal contents, which provoked considerable oxidative stress, may play an important role in esophageal carcinogenesis. Acid reflux did not induce oxidative stress in this experimental model.

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.

Emerging concepts of bile reflux in the constellation of gastroesophageal reflux disease

RATIONALE

Reflux of gastric and duodenal contents in patients with gastroesophageal reflux disease (GERD) has been postulated as a major cause of complications, such as Barrett's esophagus or malignant degeneration.

FINDINGS

We present a summary of experimental, clinical, and immunohistochemical studies that show that acid and bile reflux are increased in patients who suffer from GERD, are the key factor in the pathogenesis of Barrett's esophagus, and are possibly related to the development of esophageal adenocarcinoma.

The molecular pathogenesis of Barrett's esophagus: common signaling pathways in embryogenesis metaplasia and neoplasia

Although Barrett's esophagus has been recognized for over 50 years, the cellular and molecular mechanisms leading to the replacement of squamous esophageal epithelium with a columnar type are largely unknown. Barrett's is known to be an acquired process secondary to chronic gastroesophageal reflux disease and occurs in the presence of severe disruption of the gastroesophageal barrier and reflux of a mixture of gastric and duodenal content. Current hypothesis suggest that epithelial change occurs due to stimulation of esophageal stem cells present in the basal layers of the epithelium or submucosal glands, toward a columnar epithelial differentiation pathway. The transcription factor CDX2 seems to play a key role in promoting the cellular biology necessary for columnar differentiation, and can be induced by bile salt and acid stimulation. Several cellular signaling pathways responsible for modulation of intestinal differentiation have also been identified and include WNT, Notch, BMP, Sonic HH and TGFB. These also have been shown to respond to stimulation by bile acids, acid or both and may influence CDX2 expression. Their relative activity within the stem cell population is almost certainly responsible for the development of the esophageal columnar epithelial phenotype we know as Barrett's esophagus.

Reflux esophagitis and columnar-lined esophagus after cervical esophagogastrostomy (following esophagectomy)

Reflux esophagitis (RE) and columnar-lined esophagus (CLE) are frequently observed after esophagectomy. The incidence of these conditions according to time and to the route of esophageal reconstruction after esophagectomy remains unknown. The aim of this study was to clarify any changes and differences of the incidence of RE and CLE in patients who underwent gastric tube reconstruction after esophagectomy. A hundred patients who underwent cervical esophagogastrostomy after resection of the thoracic esophagus were included in this study. We reviewed their endoscopic findings at 1 month, at 1 year and at 2 years after surgery, and compared the incidence rates of RE and CLE with the passage of time and among the three reconstruction routes; a subcutaneous route, a retrosternal route, and a posterior mediastinal route. The incidence rate of RE was 42%, 37% and 38%, at 1 month, 1 year and at 2 years after surgery, respectively. There was no significant difference in the incidence of RE according to the time after surgery. The incidence rate of severe RE (Grade C and D in the Los Angeles Classification) was 9% percent at 1 month after surgery, 18% at 1 year after surgery and 22% at 2 years after surgery, significantly increasing with passage of time. The incidence rate of CLE was 0% at 1 month after surgery, 14% at 1 year after surgery and 40% at 2 years after surgery, significantly increasing with passage of time. No difference was observed in the incidence of RE and that of CLE among the three routes of esophageal reconstruction. Severe RE and CLE increase with passage of time after cervical esophagogastrostomy. Therefore, careful endoscopic follow-up is necessary for such patients irrespective of the route of esophageal reconstruction.

The evolution of oesophageal function testing and its clinical applications in the management of patients with oesophageal disorders

The last decade has brought significant technical advances in laparoscopic surgery. In this constantly evolving technological climate, less told is the story of the evolution of diagnostic technology that improved the clinical management of patients with oesophageal disorders. The successful outcome of the laparoscopic treatment of oesophageal disorders is due to a combination of three different factors: the skills and the ability of the foregut surgeon, the high volume of referral, the expertise in the critical evaluation of the oesophageal function tests. This is an art per se, and it is rarely acknowledged in the achievement of the excellent results of surgery. Oesophageal function testing provides the clinician with information that cannot be obtained by the clinical, endoscopic, and radiological evaluation of patients. This expertise, intimately coupled with the other factors, allows the surgeon to better understand the pathophysiology of these diseases and to provide the optimal management. Therefore, it is essential to understand the evolution that this technology is currently undergoing, and how these changes are expanding the current indications for antireflux surgery by identifying additional predictors of successful outcome.

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.

Inhibition of nucleostemin upregulates CDX2 expression in HT29 cells in response to bile acid exposure: implications in the pathogenesis of Barrett's esophagus

BACKGROUND

Barrett's esophagus (BE), a squamous-to-columnar metaplasia, may originate from growth-promoting mutations in metaplastic stem cells. Nucleostemin is a protein highly expressed in undifferentiated embryonic stem cells. The objectives of this study were to explore the potential role of nucleostemin in the pathogenesis of BE METHODS: The expression profiles of 30,968 genes were compared between BE and normal esophageal tissues (n = 6 in each group) by using oligo microarray. Three siRNA plasmid expression vectors against nucleostemin, pRNAi-1, pRNAi-2, and pRNAi-3, were constructed and transfected into HT29 cells. In addition, HT29 cells were exposed to 100-1,000 microM chenodeoxycholic acid (CDC), a bile acid, for 2, 12, and 24 h, and then messenger RNA and protein expressions of nucleostemin and CDX2 were determined by reverse-transcriptase polymerase chain reaction and Western blotting.

RESULTS

Four hundred and twenty-six differentially expressed genes were detected in BE; 142 were upregulated and 284 downregulated. Nucleostemin was downregulated while CDX2 was upregulated. In vitro, all the recombinant plasmids inhibited the nucleostemin expression in transfected HT29 cells, with pRNAi-1 being the most effective. CDX2 expression was significantly increased in pRNAi-1-transfected HT29 cells, compared with that in the empty plasmid (pRNAT-U6.1/Neo) transfected or untransfected HT29 cells. In addition, CDX2 expression was increased whereas nucleostemin expression was decreased in a dose- and time-dependent manner in HT29 cells treated with CDC.

CONCLUSION

These findings suggest that the inhibition of nucleostemin expression in "esophageal stem cells" in response to bile acid exposure may be involved in the pathogenesis of BE through upregulating CDX2 expression.

Inflammation and esophageal carcinogenesis

The incidence of esophageal adenocarcinoma is increasing largely in Western populations, and patients diagnosed with this cancer continue to have a poor prognosis. The major risk factors are gastroesophageal reflux disease and Barrett's esophagus, both of which are associated with inflammation of the esophageal squamous epithelium, a condition called reflux esophagitis. The cellular mechanisms contributing to cancer development in the esophagus are poorly understood. The chronic inflammation that is present in Barrett's esophagus creates an environment suitable for DNA damage and altered expression of genes involved in cellular proliferation and inhibition of apoptosis. Key players in the inflammatory cascade include generation of free radicals, activation of kinases pathways and transcription factors, and production of cytokines and inflammatory enzymes. The current review highlights the link between reflux-induced inflammation and esophageal carcinogenesis. Understanding the molecular pathways involved in inflammation-associated esophageal tumorigenesis could enable the development of targeted therapies and offer a better therapeutic treatment in esophageal cancer.

Deoxycholate induces COX-2 expression via Erk1/2-, p38-MAPK and AP-1-dependent mechanisms in esophageal cancer cells

Background

The progression from Barrett's metaplasia to adenocarcinoma is associated with the acquirement of an apoptosis-resistant phenotype. The bile acid deoxycholate (DCA) has been proposed to play an important role in the development of esophageal adenocarcinoma, but the precise molecular mechanisms remain undefined. The aim of this study was to investigate DCA-stimulated COX-2 signaling pathways and their possible contribution to deregulated cell survival and apoptosis in esophageal adenocarcinoma cells.

Methods

Following exposure of SKGT-4 cells to DCA, protein levels of COX-2, MAPK and PARP were examined by immunoblotting. AP-1 activity was assessed by mobility shift assay. DCA-induced toxicity was assessed by DNA fragmentation and MTT assay.

Results

DCA induced persistent activation of the AP-1 transcription factor with Fra-1 and JunB identified as the predominant components of the DCA-induced AP-1 complex. DCA activated Fra-1 via the Erk1/2- and p38 MAPK while Erk1/2 is upstream of JunB. Moreover, DCA stimulation mediated inhibition of proliferation with concomitant low levels of caspase-3-dependent PARP cleavage and DNA fragmentation. Induction of the anti-apoptotic protein COX-2 by DCA, via MAPK/AP-1 pathway appeared to balance the DCA mediated activation of pro-apoptotic markers such as PARP cleavage and DNA fragmentation. Both of these markers were increased upon COX-2 suppression by aspirin pretreatment prior to DCA exposure.

Conclusion

DCA regulates both apoptosis and COX-2-regulated cell survival in esophageal cells suggesting that the balance between these two opposing signals may determine the transformation potential of DCA as a component of the refluxate.

P53 and Ki-67 overexpression in gastroesophageal reflux disease--Barrett's esophagus and adenocarcinoma sequence

Gastroesophageal reflux disease (GERD) is a major risk factor for the development of esophageal adenocarcinoma (ACE). Many molecular alterations occur in esophageal carcinogenesis, yet the exact mechanism of ACE development remains unknown. This study aims to determine p53 protein and Ki-67 expression in esophageal mucosa of patients with GERD and study the correlation between these markers and the progression from normal squamous epithelium to esophagitis, columnar epithelium with or without intestinal metaplasia and ACE. We analyzed p53 protein and Ki-67 expression in biopsies of 200 patients with GERD and 35 patients with ACE. Those biopsies were classified into five groups: (i) G1 normal squamous epithelium (58); (ii) G2 esophagitis (80); (iii) G3 columnar epitheliums without intestinal metaplasia (30); (iv) G4, columnar epitheliums with intestinal metaplasia (32); and (v) G5 ACEs (35). p53 protein overexpression was found in 7% (4) of G1, 37.5% (30) of G2, 30% (9) of G3, 62.5% (20) of G4, and 71.4% (25) of G5 (p < 0.001). Ki-67 index increased according to the severity of histopathological diagnoses. Ki67 index was 21.3 +/- 19.5% in G1, 38.8 +/- 24.9% in G2, 37.7 +/- 26.3% in G3, 52.8 +/- 24.6% in G4, and 57.1 +/- 25.1% in G5 (P < 0.001). Linear correlation between p53/Ki67 expression and the multistep progression from squamous epithelium to ACE was observed (P < 0.001 and P < 0.05). Our results indicate that overexpression of p53 and increased Ki-67 could be associated with the development and progression to ACE in patients with GERD.

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.