Review article: management of oesophageal adenocarcinoma -- control of acid, bile and inflammation in intervention strategies for Barrett's oesophagus

Trends in gastroesophageal reflux disease research: A bibliometric and visualized study

Background

Gastroesophageal reflux disease (GERD), a disorder resulting from the retrograde flow of gastric contents into the esophagus, affects an estimated 10-30% of the Western population, which is characterized by multifactorial pathogenesis. Over the past few decades, there have been many aspects of uncertainty regarding GERD leading to an ongoing interest in the field as reflected by a large number of publications, whose heterogeneity and variable quality may present a challenge for researchers to measure their scientific impact, identify scientific collaborations, and to grasp actively researched themes in the GERD field. Accordingly, we aim to evaluate the knowledge structure, evolution of research themes, and emerging topics of GERD research between 2012 and 2022 with the help of bibliometric approaches.

Methods

The literature focusing on GERD from 2012 to 2022 was retrieved from the Science Citation Index Expanded of the Web of Science Core Collection. The overall publication performance, the most prolific countries or regions, authors, journals and resources-, knowledge- and intellectual-networking, as well as the co-citation analysis of references and keywords, were analyzed through Microsoft Office Excel 2019, CiteSpace, and VOSviewer.

Results

A total of 8,964 publications were included in the study. The USA published the most articles (3,204, 35.74%). Mayo Clin ranked first in the number of articles published (201, 2.24%). EDOARDO SAVARINO was the most productive author (86, 0.96%). The most productive journal in this field was SURGICAL ENDOSCOPY AND OTHER INTERVENTIONAL TECHNIQUES (304, 3.39%). AMERICAN JOURNAL OF GASTROENTEROLOGY had the most co-citations (4,953, 3.30%). Keywords with the ongoing strong citation bursts were transoral incision less fundoplication, eosinophilic esophagitis, baseline impedance, and functional heartburn.

Conclusion

For the first time, we obtained deep insights into GERD research through bibliometric analysis. Findings in this study will be helpful for scholars seeking to understand essential information in this field and identify research frontiers.

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

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

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

Importance

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

Objectives

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

Design, Setting, and Participants

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

Exposures

Antireflux surgery for GERD.

Main Outcomes and Measures

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

Results

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

Conclusions and Relevance

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

TGR5 expression in benign, preneoplastic and neoplastic lesions of Barrett’s esophagus: Case series and findings

AIM

To examined the bile acid receptor TGR5 expression in squamous mucosa, Barrett’s mucosa, dysplasia and esophageal adenocarcinoma (EA).

METHODS

Slides were stained with TGR5 antibody. The staining intensity was scored as 1+, 2+ and 3+. The extent of staining (percentage of cells staining) was scored as follows: 1+, 1%-10%, 2+, 11%-50%, 3+, 51%-100%. A combined score of intensity and extent was calculated and categorized as negative, weak, moderate and strong staining. TGR5 mRNA was measured by real time PCR.

RESULTS

We found that levels of TGR5 mRNA were significantly increased in Barrett’s dysplastic cell line CP-D and EA cell line SK-GT-4, when compared with Barrett’s cell line CP-A. Moderate to strong TGR5 staining was significantly higher in high-grade dysplasia and EA cases than in Barrett’s esophagus (BE) or in low-grade dysplasia. Moderate to strong staining was slightly higher in low-grade dysplasia than in BE mucosa, but there is no statistical significance. TGR5 staining had no significant difference between high-grade dysplasia and EA. In addition, TGR5 staining intensity was not associated with the clinical stage, the pathological stage and the status of lymph node metastasis.

CONCLUSION

We conclude that TGR5 immunostaining was much stronger in high-grade dysplasia and EA than in BE mucosa or low-grade dysplasia and that its staining intensity was not associated with the clinical stage, the pathological stage and the status of lymph node metastasis. TGR5 might be a potential marker for the progression from BE to high-grade dysplasia and EA.

Bile acid receptor TGR5, NADPH Oxidase NOX5-S and CREB Mediate Bile Acid-Induced DNA Damage In Barrett's Esophageal Adenocarcinoma Cells

The mechanisms whereby bile acid reflux may accelerate the progression from Barrett’s esophagus (BE) to esophageal adenocarcinoma (EA) are not fully understood. In this study we found that bile acid taurodeoxycholic acid (TDCA) significantly increased the tail moment (TM) and histone H2AX phosphorylation in FLO-1 EA cells, an increase which was significantly decreased by knockdown of TGR5. Overexpression of TGR5 significantly increased TDCA-induced TM increase and H2AX phosphorylation. In addition, NADPH oxidase inhibitor diphenylene iodonium significantly inhibited the TDCA-induced increase in TM and H2AX phosphorylation. TDCA-induced increase in TM and H2AX phosphorylation was significantly decreased by knockdown of NOX5-S and overexpression of NOX5-S significantly increased TDCA-induced increase in the tail moment and H2AX phosphorylation. Furthermore, TDCA significantly increased cAMP response element binding protein (CREB) phosphorylation in FLO-1 cells. Knockdown of CREB significantly decreased TDCA-induced increase in NOX5-S mRNA and the tail moment. Conversely, overexpression of CREB significantly increased TDCA-induced TM increase. We conclude that TDCA-induced DNA damage may depend on the activation of TGR5, CREB and NOX5-S. It is possible that in Barrett’s patients bile acids may activate NOX5-S and increase reactive oxygen species (ROS) production via activation of TGR5 and CREB. NOX5-S-derived ROS may cause DNA damage, thereby contributing to the progression from BE to EA.

Evidence-based clinical practice guidelines for gastroesophageal reflux disease 2015

As an increase in gastroesophageal reflux disease (GERD) has been reported in Japan, and public interest in GERD has been increasing, the Japanese Society of Gastroenterology published the Evidence-based Clinical Practice Guidelines for GERD (1st edition) in 2009. Six years have passed since its publication, and there have been a large number of reports in Japan concerning the epidemiology, pathophysiology, treatment, and Barrett's esophagus during this period. By incorporating the contents of these reports, the guidelines were completely revised, and a new edition was published in October 2015. The revised edition consists of eight items: epidemiology, pathophysiology, diagnosis, internal treatment, surgical treatment, esophagitis after surgery of the upper gastrointestinal tract, extraesophageal symptoms, and Barrett's esophagus. This paper summarizes these guidelines, particularly the parts related to the treatment for GERD. In the present revision, aggressive proton pump inhibitor (PPI) maintenance therapy is recommended for severe erosive GERD, and on-demand therapy or continuous maintenance therapy is recommended for mild erosive GERD or PPI-responsive non-erosive GERD. Moreover, PPI-resistant GERD (insufficient symptomatic improvement and/or esophageal mucosal break persisting despite the administration of PPI at a standard dose for 8 weeks) is defined, and a standard-dose PPI twice a day, change in PPI, change in the PPI timing of dosing, addition of a prokinetic drug, addition of rikkunshito (traditional Japanese herbal medicine), and addition of histamine H2-receptor antagonist are recommended for its treatment. If no improvement is observed even after these treatments, pathophysiological evaluation with esophageal impedance-pH monitoring or esophageal manometry at an expert facility for diseases of the esophagus is recommended.

How good is the neosquamous epithelium?

BACKGROUND/AIMS

Endoscopic radiofrequency ablation of dysplastic Barrett's esophagus (BE) combined with proton pump inhibitor therapy is commonly utilized for preventing progression of dysplastic BE to esophageal adenocarcinoma. Fundamental to the success of this and all ablative approaches is the healing of the ablated areas of BE with a stratified squamous epithelium referred to as 'neosquamous epithelium' (NSE). Although NSE appears 'normal' endoscopically, the reemergence of BE over time in the previously ablated segments raises the question of the health and integrity of NSE.

METHODS

The health of NSE was recently investigated in endoscopic biopsies in vitro in a group of patients after ablation while on proton pump inhibitors. Biopsies of NSE were compared to upper squamous epithelium (USE) from the same patients morphologically (light microscopy) and with respect to barrier function by measuring electrical resistance and fluorescein flux in mini-Ussing chambers.

RESULTS

Compared to USE, NSE exhibited dilated intercellular spaces and inflammation and defective barrier function by low electrical resistance and high fluorescein flux. Moreover, NSE exhibited downregulation of claudin-4, a highly expressed protein in squamous tight junctions.

CONCLUSION

NSE has defective barrier function in part due to downregulation of claudin-4. Since downregulation of claudin-4 increases paracellular permeability to cations, e.g. hydrogen ions, NSE is more vulnerable to attack and damage by acidic and weakly acidic refluxates--a phenomenon that may contribute in part to the reemergence of BE.

Increased expression of the 5-lipoxygenase pathway and its cellular localization in Barrett's adenocarcinoma

AIMS

Up-regulation of the 5-lipoxygenase (5-LOX) leukotriene pathway is evident in numerous tumour types, and has been linked to the promotion of cancer cell growth. The aim of this study was to evaluate the immunohistochemical expression of 5-LOX pathway proteins in oesophageal adenocarcinoma and its premalignant lesion, Barrett's metaplasia.

METHODS AND RESULTS

Tissue samples were collected at endoscopy from 16 patients with Barrett's metaplasia and from seven with oesophageal adenocarcinoma; five proximal squamous oesophagus samples were used as controls. Immunohistochemical analyses were performed on stromal and epithelial areas with optimized concentrations of primary antibodies for 5-LOX, 5-LOX-activating protein (FLAP), and the distal enzymes leukotriene (LT) A(4) hydrolase (LTA(4) H) and LTC(4) synthase (LTC(4) S). the diagnosis was histologically confirmed from adjacent sections by a gastrointestinal pathologist. Striking increases in the stromal immunoexpression of 5-LOX (P = 0.041), FLAP (P = 0.038), LTA(4) H (P = 0.0008) and LTC(4) S (P = 0.036) were seen in adenocarcinoma tissue. Stromal FLAP and LTA(4) H immunostaining correlated with elevated neutrophil counts (P < 0.001). LTC(4) S was also notably overexpressed within epithelial cells in both Barrett's metaplasia (P < 0.001) and adenocarcinoma (P < 0.01) tissue.

CONCLUSIONS

Key biosynthetic enzymes of the LTB(4) and LTC(4) biosynthetic pathways are incrementally expressed across the spectrum of squamous, Barrett's metaplasia and oesophageal adenocarcinoma tissues, suggesting, for the first time, a role for both LT subfamilies in disease progression.

Aspirin and cancer: has aspirin been overlooked as an adjuvant therapy?

Aspirin inhibits the enzyme cyclooxygenase (Cox), and there is a significant body of epidemiological evidence demonstrating that regular aspirin use is associated with a decreased incidence of developing cancer. Interest focussed on selective Cox-2 inhibitors both as cancer prevention agents and as therapeutic agents in patients with proven malignancy until concerns were raised about their toxicity profile. Aspirin has several additional mechanisms of action that may contribute to its anti-cancer effect. It also influences cellular processes such as apoptosis and angiogenesis that are crucial for the development and growth of malignancies. Evidence suggests that these effects can occur through Cox-independent pathways questioning the rationale of focussing on Cox-2 inhibition alone as an anti-cancer strategy. Randomised studies with aspirin primarily designed to prevent cardiovascular disease have demonstrated a reduction in cancer deaths with long-term follow-up. Concerns about toxicity, particularly serious haemorrhage, have limited the use of aspirin as a cancer prevention agent, but recent epidemiological evidence demonstrating regular aspirin use after a diagnosis of cancer improves outcomes suggests that it may have a role in the adjuvant setting where the risk:benefit ratio will be different.

New models of neoplastic progression in Barrett's oesophagus

Research in Barrett's oesophagus, and neoplastic progression to OAC (oesophageal adenocarcinoma), is hobbled by the lack of good pre-clinical models that capture the evolutionary dynamics of Barrett's cell populations. Current models trade off tractability for realism. Computational models are perhaps the most tractable and can be used both to interpret data and to develop intuitions and hypotheses for neoplastic progression. Tissue culture models include squamous cell lines, Barrett's oesophagus cell lines and OAC cell lines, although it was recognized recently that BIC-1, SEG-1 and TE-7 are not true OAC cell lines. Some of the unrealistic aspects of the micro-environment in two-dimensional tissue culture may be overcome with the development of three-dimensional organotypic cultures of Barrett's oesophagus. The most realistic, but least tractable, model is a canine surgical model that generates reflux and leads to an intestinal metaplasia. Alternatively, rat surgical models have gained popularity and should be tested for the common genetic features of Barrett's oesophagus neoplastic progression in humans including loss of CDKN2A (cyclin-dependent kinase inhibitor 2A) and TP53 (tumour protein 53), generation of aneuploidy and realistic levels of genetic diversity. This last feature will be important for studying the effects of cancer-prevention interventions. In order to study the dynamics of progression and the effects of an experimental intervention, there is a need to follow animals longitudinally, with periodic endoscopic biopsies. This is now possible and represents an exciting opportunity for the future.

New models of neoplastic progression in Barrett's oesophagus

Research in Barrett's oesophagus, and neoplastic progression to OAC (oesophageal adenocarcinoma), is hobbled by the lack of good pre-clinical models that capture the evolutionary dynamics of Barrett's cell populations. Current models trade off tractability for realism. Computational models are perhaps the most tractable and can be used both to interpret data and to develop intuitions and hypotheses for neoplastic progression. Tissue culture models include squamous cell lines, Barrett's oesophagus cell lines and OAC cell lines, although it was recognized recently that BIC-1, SEG-1 and TE-7 are not true OAC cell lines. Some of the unrealistic aspects of the micro-environment in two-dimensional tissue culture may be overcome with the development of three-dimensional organotypic cultures of Barrett's oesophagus. The most realistic, but least tractable, model is a canine surgical model that generates reflux and leads to an intestinal metaplasia. Alternatively, rat surgical models have gained popularity and should be tested for the common genetic features of Barrett's oesophagus neoplastic progression in humans including loss of CDKN2A (cyclin-dependent kinase inhibitor 2A) and TP53 (tumour protein 53), generation of aneuploidy and realistic levels of genetic diversity. This last feature will be important for studying the effects of cancer-prevention interventions. In order to study the dynamics of progression and the effects of an experimental intervention, there is a need to follow animals longitudinally, with periodic endoscopic biopsies. This is now possible and represents an exciting opportunity for the future.

Bile acid reflux contributes to development of esophageal adenocarcinoma via activation of phosphatidylinositol-specific phospholipase Cgamma2 and NADPH oxidase NOX5-S

Gastroesophageal reflux disease complicated by Barrett's esophagus (BE) is a major risk factor for esophageal adenocarcinoma (EA). However, the mechanisms of the progression from BE to EA are not fully understood. Besides acid reflux, bile acid reflux may also play an important role in the progression from BE to EA. In this study, we examined the role of phosphatidylinositol-specific phospholipase C (PI-PLC) and a novel NADPH oxidase NOX5-S in bile acid-induced increase in cell proliferation. We found that taurodeoxycholic acid (TDCA) significantly increased NOX5-S expression, hydrogen peroxide (H(2)O(2)) production, and cell proliferation in EA cells. The TDCA-induced increase in cell proliferation was significantly reduced by U73122, an inhibitor of PI-PLC. PI-PLCbeta1, PI-PLCbeta3, PI-PLCbeta4, PI-PLCgamma1, and PI-PLCgamma2, but not PI-PLCbeta2 and PI-PLCdelta1, were detectable in FLO cells by Western blot analysis. Knockdown of PI-PLCgamma2 or extracellular signal-regulated kinase (ERK) 2 mitogen-activated protein (MAP) kinase with small interfering RNAs (siRNA) significantly decreased TDCA-induced NOX5-S expression, H(2)O(2) production, and cell proliferation. In contrast, knockdown of PI-PLCbeta1, PI-PLCbeta3, PI-PLCbeta4, PI-PLCgamma1, or ERK1 MAP kinase had no significant effect. TDCA significantly increased ERK2 phosphorylation, an increase that was reduced by U73122 or PI-PLCgamma2 siRNA. We conclude that TDCA-induced increase in NOX5-S expression and cell proliferation may depend on sequential activation of PI-PLCgamma2 and ERK2 MAP kinase in EA cells. It is possible that bile acid reflux present in patients with BE may increase reactive oxygen species production and cell proliferation via activation of PI-PLCgamma2, ERK2 MAP kinase, and NADPH oxidase NOX5-S, thereby contributing to the development of EA.

Aspirin and non-steroidal anti-inflammatory drugs for cancer prevention: an international consensus statement

Evidence clearly shows a chemopreventive effect for aspirin and other non-steroidal anti-inflammatory drugs (NSAIDs) on colorectal cancer and probably other cancer types; however, data on the risk-benefit profile for cancer prevention are insufficient and no definitive recommendations can be made. Aspirin has emerged as the most likely NSAID for use in chemoprevention because of its known cardiovascular benefit and available safety and efficacy data. Other traditional NSAIDs, particularly sulindac, and selective COX-2 inhibitors are now given to patients at high risk of colorectal cancer, although these drugs do not provide cardioprotection. More studies of aspirin and cancer prevention are needed to define the lowest effective dose, the age at which to initiate therapy, the optimum treatment duration, and the subpopulations for which the benefits of chemoprevention outweigh the risks of adverse side-effects. Although it might be possible to answer some of these questions with longer follow-up of existing clinical trials, randomised controlled trials with new study designs will be needed. Future projects should investigate the effects of aspirin treatment on multiple organ systems. Cancers of interest are colorectal, breast, prostate, lung, stomach, and oesophageal. The main side-effect of aspirin is peptic ulcers; therefore coadministration of aspirin with a proton-pump inhibitor is an attractive option and is under investigation in the AspECT trial.

Barrett's esophagus: where do we stand?

Barrett's esophagus (BE) is a precursor for esophageal adenocarcinoma, which has an increased incidence rate over the last few decades. Its importance stems from the poor five-year survival of esophageal adenocarcinoma and current data that suggest a survival benefit when surveillance programs are implemented. In this review, we will cover the pathophysiology and natural history of BE and the different endoscopic findings. The prevalence of BE in different geographic areas and the incidence of high-grade dysplasia and adenocarcinoma in this patient population is reviewed. Recent recommendation for screening and surveillance of BE has been covered in this review as well as the efficacy of nonconventional imaging modalities and endoscopic ablation therapies.

Cyclooxygenase-2 inhibitors in colorectal cancer prevention: counterpoint

Aspirin is the best chemoprevention agent for colorectal cancer risk reduction despite the fact that the evidence for a decrease in mortality is weak. The cyclooxygenase-2 selective agents (COXIBS) have an efficacy similar to that of aspirin for most gastrointestinal (GI) lesions but not esophagus. Specifically, there are beneficial short term effects of COXIBs on the risk of colorectal adenoma as shown in the Approve, PreSAP, and APC studies. However, there is still an increased risk of upper GI complications with COXIBs when compared with placebo, and this risk may increase further in some people when aspirin is also consumed. Whereas aspirin reduces the risk of cardiovascular events, COXIBs and most traditional nonsteroidal anti-inflammatory drugs (but not all) are both associated with an increased risk of thrombotic cardiovascular events compared with placebo. In conclusion, COXIBs have a niche role for patients with familial adenomatous polyposis. The value of aspirin remains with respect for efficacy, mainly in the esophagus, and the side effect profile, especially in the elderly if given with acid suppression therapy. COXIBs should be used in younger populations, but if they are considered in the elderly because of increased GI risks, and the cardiovascular risk is also increased, then combination treatment with aspirin and a proton-pump inhibitor should also be considered instead, such as in the ASPECT trial.

Sorafenib inhibits MAPK-mediated proliferation in a Barrett's esophageal adenocarcinoma cell line

Esophageal adenocarcinoma continues to rise in incidence. Despite recognition of Barrett's metaplasia as the histological precursor, prognosis remains poor. The mitogen-activated protein kinases (MAPK) pathway is activated in Barrett's-associated dysplasia and adenocarcinoma and this activation is, in part, due to acid and bile acid reflux. We investigated the effects of sorafenib, an orally active Raf-inhibitor, on acid and bile acid-stimulated growth and signaling in SEG-1 cells, derived from a Barrett's esophageal cancer. SEG-1 cells were pretreated with sorafenib or vehicle and subsequently stimulated with acid or bile acid. MAPK signals, including phospho-ERK and phospho-p38, as well as cyclin D1 expression were assessed by Western blotting. Cell proliferation was measured by WST-1 colorimetric assay. Acid (pH 3.0-4.0) and bile acid (taurocholate 50-100 micromol/L) activated ERK and p38. Acid and bile acid exposure also increased levels of cyclin D1, a G1 to S cell cycle regulator. Furthermore, acid and taurocholate exposure increased cell proliferation. Sorafenib abrogated MAPK activation and cyclin D1 up-regulation and significantly inhibited cell growth. In summary, sorafenib inhibits acid or bile acid-stimulated Barrett's esophageal cancer cell proliferation by a mechanism involving the MAPK pathway. Our results suggest that sorafenib might be useful in the management of Barrett's-associated dysplasia and adenocarcinoma. These findings provide a foundation for in vivo studies to assess the efficacy of sorafenib in Barrett's-related neoplasia.

Alterations of glutathione S-transferase and matrix metalloproteinase-9 expressions are early events in esophageal carcinogenesis

AIM

To investigate the role of glutathione S-transferase (GST) and matrix metalloproteinase-9 (MMP-9) expressions in the development and progression of reflux esophagitis-Barrett's metaplasia-dysplasia-adenocarcinoma sequence in the esophagus.

METHODS

GST and MMP-9 expressions were analyzed in 51 paraffin-embedded tissue samples by immunohistochemistry including patients with reflux esophagitis (n = 7), Barrett's metaplasia (n = 14), Barrett and esophagitis (n = 8), Barrett and dysplasia (n = 7), esophageal adenocarcinoma (n = 8) and a control group without any histological changes (n = 7). Immunostaining was determined semiquantitatively. Statistical analysis with one-way ANOVA, LSD test and correlation analysis were performed. P value of < 0.05 was considered significant.

RESULTS

GST expression was significantly higher while MMP-9 expression was significantly lower in control group compared to Barrett's metaplasia and the other groups. No major changes were observed between Barrett, esophagitis, and Barrett and concomitant esophagitis. Barrett and concomitant dysplasia, and adenocarcinoma revealed a significant lower expression of GST and higher levels of MMP-9 compared to all other groups. Adenocarcinoma showed almost no expression of GST and significantly higher levels of MMP-9 than Barrett and concomitant dysplasia. Alterations of GST and MMP-9 were inversely correlated (r = -0.82).

CONCLUSION

Decreased GST and increased expression of MMP-9 in Barrett's metaplasia-dysplasia-adenocarcinoma sequence as compared to normal tissue suggest their association with esophageal tumorigenesis. Loss of GST and gain of MMP-9 in Barrett with dysplasia compared to non-dysplastic metaplasia indicate that these alterations may be early events in carcinogenesis. Quantification of these parameters in Barrett's esophagus might be useful to identify patients at higher risk for progression to cancer.

The effect of photodynamic therapy (PDT) on oesophageal motility and acid clearance in patients with Barrett’s oesophagus

BACKGROUND

Barrett's oesophagus is the major risk factor for oesophageal adenocarcinoma. It is proposed that long-term re-epithelialisation, which has been achieved following ablation using 5-aminolaevulinic acid (5-ALA) photodynamic therapy (PDT) may reduce the risk of malignant change. However, it is not known whether PDT modifies oesophageal motility.

AIM

To assess oesophageal pH and motility before and after PDT ablation in treated and untreated areas of the oesophagus.

METHODS

Twelve patients (10 male) with Barrett's oesophagus, median segment length 4 cm, were treated with PDT ablation. Twenty-four hours pH assessment and oesophageal manometry were performed before and 4-6 weeks after ablation. PDT was carried out using 635 nm red light, 4-6h after administration of 30 mg/kg 5-ALA. Proximal (untreated) and distal (treated) oesophageal resting pressure, wave amplitude, percentage peristalsis and percentage study time oesophageal pH<4, were assessed. Proton pump inhibitors (PPI) were administered throughout the study.

RESULTS

There were no significant differences in oesophageal motility in treated or untreated areas of the oesophagus after PDT compared to pre-treatment values. Patients who continued to experience oesophageal acid exposure required more treatments to achieve complete Barrett's ablation.

CONCLUSIONS

Oesophageal motility following ALA-PDT suggests a trend toward enhanced wave propagation however continued oesophageal acid exposure may affect PDT efficacy.

Changes in esophageal motility after porfimer sodium photodynamic therapy for Barrett's dysplasia and mucosal carcinoma

Esophageal dysmotility is common in patients with Barrett's esophagus. Previously we have reported deterioration of esophageal motility after photodynamic therapy (PDT) in a heterogeneous group of patients with esophageal carcinoma. This prospective study in consecutive patients describes changes in motility noted after endoscopic ablation. Forty-seven patients referred to our institution for endoscopic ablation for Barrett's high grade dysplasia or mucosal carcinoma between August 2001 and May 2003 were prospectively evaluated with esophageal manometry before and after porfimer sodium PDT. Six patients did not complete the study. Manometry results were classified as normal, diffuse esophageal spasm, ineffective esophageal motility, or aperistalsis. Abnormal esophageal motility was found in 14 of 47 (30%) patients at study entry ([diffuse esophageal spasm] DES-3, [ineffective esophageal motility] IEM-7, Aperistalsis-4). After PDT, 11 of 41 patients with paired studies experienced a change in manometric diagnosis. Three patients had an improvement in motility, seven a worsening and one changed diagnosis, but did not particularly worsen or improve. No patient developed new aperistalsis. Therefore, abnormal motility was present in 19 of 41 (46%) patients after PDT (DES-2, IEM-14, Aperistalsis-3). There was a statistically significant (P = 0.016) relationship with longer segment Barrett's esophagus and deterioration of function. Baseline abnormalities in motility can occur in patients with Barrett's high-grade dysplasia or mucosal carcinoma. Changes in esophageal function also may occur following photodynamic therapy, but usually are not clinically significant. Worsening in function was more likely to occur in patients with longer segment Barrett's esophagus.

Risk factors for the development of esophageal adenocarcinoma in Barrett's esophagus

OBJECTIVE

To identify risk factors for esophageal adenocarcinoma (EAC) in patients with Barrett's esophagus (BE).

METHODS

A hospital-based case-control study was performed in which 91 cases with EAC and 244 controls with histologically confirmed BE (>2 cm) with no dysplasia or low-grade dysplasia were included. Information on demographic, anthropometric, and lifestyle characteristics, physical activity levels, working posture, family history, gastroesophageal reflux disease (GERD) symptoms, and medication use was collected by questionnaire.

RESULTS

Cases more often were current smokers (odds ratio 3.7, 95% confidence interval 1.4-9.9), more often had a body mass index >25 assessed at age 20 (2.6, 1.2-5.5), and more frequently had been working in a stooped posture at age 20 (2.0, 1.1-3.9), compared to controls. In addition, cases less often experienced symptoms of heartburn (0.3, 0.2-0.5) and less frequently used proton pump inhibitors (0.1, 0.05-0.2), compared to controls, whereas use of nonsteroidal anti-inflammatory drugs/aspirin was more common among cases (1.8, 1.1-3.2). Cases more often were men, compared to controls (91%vs 67%, p < 0.001).

CONCLUSION

In patients with BE, the risk of EAC is related to risk factors for GERD, which is, however, asymptomatic. As these risk factors are common in Western countries, they are probably not helpful in individualization of surveillance intervals.

Continuous treatment of Barrett's oesophagus patients with proton pump inhibitors up to 13 years: observations on regression and cancer incidence

BACKGROUND

There is little evidence that treatment of patients with Barrett's oesophagus with proton pump inhibitors over periods up to 6 years results in major regression of Barrett's oesophagus.

AIM

To determine if longer periods of treatment with proton pump inhibitors lead to significant regression of Barrett's oesophagus, and to determine the incidence of oesophageal adenocarcinoma in the proton pump inhibitor-treated patients.

METHODS

We analysed prospectively-collected data on Barrett's oesophagus patients treated with proton pump inhibitors for 1-13 years.

RESULTS

188 patients with Barrett's oesophagus and intestinal metaplasia, were treated for 1-13 years with a proton pump inhibitor (966 years of treatment; mean 5.1 years). No change in length was seen during treatment but 48% of patients developed squamous islands (25% after 1-3 years; 100% at 12-13 years). Squamous islands correlated with treatment duration and male sex but not with proton pump inhibitor dose or patient age. Six patients developed dysplasia and three males developed adenocarcinoma during treatment (cancer incidence 0.31%).

CONCLUSIONS

Proton-pump inhibitor treatment over 1-13 years does not shorten the Barrett's oesophagus segment but squamous islands appear in many patients. The incidence of oesophageal adenocarcinoma was low in these proton pump inhibitor-treated patients compared with published series.

Bile salts inhibit growth and induce apoptosis of culture human normal esophageal mucosal epithelial cells

AIM: To investigate the effect of six bile salts: glycocholate (GC), glycochenodeoxycholate (GCDC), glycodeoxycholate (GDC), taurocholate (TC), taurochenodeoxycholate (TCDC), taurodeoxycholate (TDC), and their mixture on cultured human normal esophageal mucosal epithelial cells.

METHODS: Human normal esophageal mucosal epithelial cells were cultured with serum-free keratinocyte medium. 3-[4,5-Dimethylthiaolyl]-2,5-diphenyl-tetrazolium bromide assay was applied to the detection of cell proliferation. Apoptotic morphology was observed by phase-contrast video microscopy and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay. Sub-G1 DNA fragmentations and early apoptotic cells were assayed by flow cytometry (FCM) with propidium iodide (PI) staining and annexin V-FITC conjugated with PI staining. Apoptotic DNA ladders on agarose gel electrophoresis were observed.

RESULTS: Except for GC, GCDC, GDC, TC, TCDC, TDC and their mixture could initiate growth inhibition of esophageal mucosal epithelial cells in a dose- and time-dependent manner. TUNEL and FCM assays demonstrated that the bile salts at 500 μmol/L and their mixture at 1 500 μmol/L induced apoptosis except for GC. The percentage of sub-G1 detected by FCM with PI staining was 83.5% in cells treated with 500 μmol/L TC for 2 h, and 19.8%, 20.4%, 25.6%, 13.5%, and 75.8% in cells treated with 500 μmol/L GCDC, TCDC, GDC, TDC, and 1 500 μmol/L mixture for 24 h, respectively, which were higher than that of the control (1.5%). The percentage was 1.4% in cells with 500 μmol/L GC for 24 h. DNA ladders on agarose gel electrophoresis were seen in cells treated with 500 μmol/L TC for 2 h and 1 500 μmol/L mixture for 24 h.

CONCLUSION: All GCDC, GDC, TC, TCDC, TDC and their mixture can inhibit growth and induce apoptosis of cultured human normal esophageal mucosal epithelial cells, but GC is well tolerated by the cells.

Expression profile of malignant and nonmalignant lesions of esophagus and stomach: differential activity of functional modules related to inflammation and lipid metabolism

Adenocarcinomas of stomach and esophagus are frequently associated with preceding inflammatory alterations of the normal mucosa. Whereas intestinal metaplasia of the gastric mucosa is associated with higher risk of malignization, Barrett's disease is a risk factor for adenocarcinoma of the esophagus. Barrett's disease is characterized by the substitution of the squamous mucosa of the esophagus by a columnar tissue classified histopathologically as intestinal metaplasia. Using cDNA microarrays, we determined the expression profile of normal gastric and esophageal mucosa as well as intestinal metaplasia and adenocarcinomas from both organs. Data were explored to define functional alterations related to the transformation from squamous to columnar epithelium and the malignant transformation from intestinal metaplasia to adenocarcinomas. Based on their expression profile, adenocarcinomas of the esophagus showed stronger correlation with intestinal metaplasia of the stomach than with Barrett's mucosa. Second, we identified two functional modules, lipid metabolism and cytokine, as being altered with higher statistical significance. Whereas the lipid metabolism module is active in samples representing intestinal metaplasia and inactive in adenocarcinomas, the cytokine module is inactive in samples representing normal esophagus and esophagitis. Using the concept of relevance networks, we determined the changes in linear correlation of genes pertaining to these two functional modules. Exploitation of the data presented herein will help in the precise molecular characterization of adenocarcinoma from the distal esophagus, avoiding the topographical and descriptive classification that is currently adopted, and help with the proper management of patients with Barrett's disease.

Bile salts inhibit growth and induce apoptosis of human esophageal cancer cell line

AIM: To explore the effect of six bile salts, including glycoc-holate (GC), glycochenodeoxycholate (GCDC), glycodeoxy-cholate (GDC), taurocholate (TC), taurochenodeoxycholate (TCDC), taurodeoxycholate (TDC), and two bile acids including cholic acid (CA) and deoxycholic acid (DCA) on esophageal cancer Eca109 cell line.

METHODS: Eca109 cells were exposed to six bile salts, two bile acids and the mixed bile salts at different concentrations for 24-72 h. 3-[4,5-Dimethylthiazol-2-yl]-2,5-diphenyl-tetrazolium bromide (MTT) assay was used to detect the cell proliferation. Apoptotic morphology was observed by phase-contrast video microscopy and deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay. Sub-G1 DNA fragmentations and early apoptosis cells were assayed by flow cytometry (FCM) with propidium iodide (PI) staining and annexin V-FITC conjugated with PI staining. Apoptosis DNA ladders on agarose were observed. Activation of caspase-3 was assayed by FCM with FITC-conjugated monoclonal rabbit anti-active caspase-3 antibody and expressions of Bcl-2 and Bax proteins were examined immunocytochemically in 500 μmol/L-TC-induced apoptosis cells.

RESULTS: Five bile salts except for GC, and two bile acids and the mixed bile salts could initiate growth inhibition of Eca109 cells in a dose- and time-dependent manner. TUNEL, FCM, and DNA ladder assays all demonstrated apoptosis induced by bile salts and bile acids at 500 μmol/L, except for GC. Early apoptosis cell percentages in Eca109 cells treated with GCDC, GDC, TC, TCDC, TDC, CA at 500 μmol/L for 12 h, DCA at 500 μmol/L for 6 h, and mixed bile salts at 1 000 μmol/L for 12 h were 7.5%, 8.7%, 14.8%, 8.9%, 7.8%, 9.3%, 22.6% and 12.5%, respectively, all were significantly higher than that in control (1.9%). About 22% of the cell population treated with TC at 500 μmol/L for 24 h had detectable active caspase-3, and were higher than that in the control (1%). Immunocytochemical assay suggested that TC down-regulated Bcl-2 protein level and up-regulated Bax protein level.

CONCLUSION: GCDC, GDC, TC, TCDC, TDC, CA and DCA, except for GC, can inhibit growth and induce apoptosis of esophageal cancer Eca109 cells. Activation of caspase-3, decreased Bcl-2 protein and increased Bax protein are involved in TC-induced apoptosis of Eca109 cells.

Molecular alterations during development of esophageal adenocarcinoma

The incidence of esophageal adenocarcinoma has risen significantly over the last decades. During esophageal carcinogenesis many molecular alterations occur that disrupt essential cellular processes, directing the cell to a rapidly proliferating, immortal state. The chronic inflammation that is present in Barrett's esophagus creates an environment in which such molecular alterations are both induced and tolerated. Here, the novel insights in the molecular mechanisms that underlie the development of esophageal adenocarcinoma are reviewed, focusing on the role of inflammation, angiogenesis, apoptosis inhibition, loss of cell cycle control, and loss of cell-cell adhesion. These novel developments will open new perspectives for diagnosis, treatment, and prevention of esophageal adenocarcinoma.