Helicobacter pylori infection and the risks of Barrett's oesophagus: a population-based case-control study

Metformin in Esophageal Carcinoma: Exploring Molecular Mechanisms and Therapeutic Insights

Esophageal cancer (EC) remains a formidable malignancy with limited treatment options and high mortality rates, necessitating the exploration of innovative therapeutic avenues. Through a systematic analysis of a multitude of studies, we synthesize the diverse findings related to metformin's influence on EC. This review comprehensively elucidates the intricate metabolic pathways and molecular mechanisms through which metformin may exert its anti-cancer effects. Key focus areas include its impact on insulin signaling, AMP-activated protein kinase (AMPK) activation, and the mTOR pathway, which collectively contribute to its role in mitigating esophageal cancer progression. This review critically examines the body of clinical and preclinical evidence surrounding the potential role of metformin, a widely prescribed anti-diabetic medication, in EC management. Our examination extends to the modulation of inflammation, oxidative stress and angiogenesis, revealing metformin's potential as a metabolic intervention in esophageal cancer pathogenesis. By consolidating epidemiological and clinical data, we assess the evidence that supports metformin's candidacy as an adjuvant therapy for esophageal cancer. By summarizing clinical and preclinical findings, our review aims to enhance our understanding of metformin's role in EC management, potentially improving patient care and outcomes.

Mechanisms for the sex-specific effect of H. pylori on risk of gastroesophageal reflux disease and Barrett's oesophagus

BACKGROUND

Mechanisms for how Helicobacter pylori infection affects risk of gastroesophageal reflux disease (GERD) and Barrett's oesophagus (BE) are incompletely understood and might differ by sex.

METHODS

In a case-control study nested in the Melbourne Collaborative Cohort Study with 425 GERD cases and 169 BE cases (identified at 2007-10 follow-up), we estimated sex-specific odds ratios for participants who were H. pylori seronegative versus seropositive at baseline (1990-94). To explore possible mechanisms, we 1) compared patterns of H. pylori-induced gastritis by sex using serum pepsinogen-I and gastrin-17 data and 2) quantified the effect of H. pylori seronegativity on BE mediated by GERD using causal mediation analysis.

RESULTS

For men, H. pylori seronegativity was associated with 1.69-fold (CI:1.03-2.75) and 2.28-fold (CI:1.27-4.12) higher odds of GERD and BE, respectively. No association was observed for women. H. pylori-induced atrophic antral gastritis was more common in men (68%) than in women (56%; p=0.015). For men, 5 of the 15 per 1,000 excess BE risk from being seronegative was mediated by GERD.

CONCLUSIONS

Men, but not women, who were H. pylori seronegative had increased risks of GERD and BE. A possible explanation might be sex-differences in patterns of H. pylori-induced atrophic antral gastritis, which could lead to less erosive reflux for men. Evidence of GERD mediating the effect of H. pylori on BE risk among men supports this proposed mechanism.

IMPACT

The findings highlight the importance of investigating sex differences in the effect of H. pylori on risk of GERD and BE in future studies.

Epidemiology of Helicobacter pylori in Australia: a scoping review

Background

Helicobacter pylori (H. pylori), a bacterium implicated in the development of peptic ulcer and gastric cancer, is estimated to infect around half the world's population. Its prevalence in Australia is unclear. This scoping review aimed to evaluate all Australian literature providing estimates of the prevalence of H. pylori.

Methods

Australian studies examining H. pylori prevalence from 1982 onwards were eligible for inclusion. Medline, Embase and Scopus databases, and grey literature sources, were searched. Two independent reviewers undertook a two-stage screening process. Data were extracted by two independent reviewers using a pre-specified template.

Results

Of 444 identified studies, 75 were included in the review. H. pylori prevalence in Australian population-based studies (n = 8) ranged from 38.0% in 1991 to 15.1% in 2002; however, estimated prevalence across all non-clinical population studies in diverse sub-groups (n = 29) has varied dramatically. Decreased prevalence has been more marked in populations with gastrointestinal symptoms and conditions compared to non-clinical populations. Data on H. pyloriprevalence in vulnerable populations are lacking.

Conclusions

This is the first scoping review of Australian studies reporting H. pylori prevalence. A wide range of study designs, population groups, geographic regions, and diagnostic methods was included, involving data collected over a 50-year period (1969 to 2018). The summary of H. pylori prevalence estimates over time in this review points to a decrease in prevalence in Australia, particularly among populations with gastrointestinal symptoms and illnesses; however, it is unknown whether there is inequity in prevalence trends across vulnerable sub-groups of the Australian population. Future research and interventions supporting the health and wellbeing of vulnerable populations is required to ensure equitable health gains are made for all.

Helicobacter pylori infection is associated with reduced risk of Barrett's esophagus: a meta-analysis and systematic review

BACKGROUND

Helicobacter pylori (Hp) is a class I carcinogen in gastric carcinogenesis, but its role in Barrett's esophagus (BE) is unknown. Therefore, we aimed to explore the possible relationship.

METHODS

We reviewed observational studies published in English until October 2019. Summary odds ratios (ORs) and 95% confidence intervals (CIs) were calculated for included studies.

RESULTS

46 studies from 1505 potential citations were eligible for inclusion. A significant inverse relationship with considerable heterogeneity was found between Hp (OR = 0.70; 95% CI, 0.51-0.96; P = 0.03) and BE, especially the CagA-positive Hp strain (OR = 0.28; 95% CI, 0.15-0.54; P = 0.0002). However, Hp infection prevalence was not significantly different between patients with BE and the gastroesophageal reflux disease (GERD) control (OR = 0.99; 95% CI, 0.82-1.19; P = 0.92). Hp was negatively correlated with long-segment BE (OR = 0.47; 95% CI, 0.25-0.90; P = 0.02) and associated with a reduced risk of dysplasia. However, Hp had no correlated with short-segment BE (OR = 1.11; 95% CI, 0.78-1.56; P = 0.57). In the present infected subgroup, Hp infection prevalence in BE was significantly lower than that in controls (OR = 0.69; 95% CI, 0.54-0.89; P = 0.005); however, this disappeared in the infection history subgroup (OR = 0.88; 95% CI, 0.43-1.78; P = 0.73).

CONCLUSIONS

Hp, especially the CagA-positive Hp strain, and BE are inversely related with considerable heterogeneity, which is likely mediated by a decrease in GERD prevalence, although this is not observed in the absence of current Hp infection.

Management of Helicobacter pylori infection: The Bhubaneswar Consensus Report of the Indian Society of Gastroenterology

The Indian Society of Gastroenterology (ISG) felt the need to organize a consensus on Helicobacter pylori (H. pylori) infection and to update the current management of H. pylori infection; hence, ISG constituted the ISG's Task Force on Helicobacter pylori. The Task Force on H. pylori undertook an exercise to produce consensus statements on H. pylori infection. Twenty-five experts from different parts of India, including gastroenterologists, pathologists, surgeons, epidemiologists, pediatricians, and microbiologists participated in the meeting. The participants were allocated to one of following sections for the meeting: Epidemiology of H. pylori infection in India and H. pylori associated conditions; diagnosis; treatment and retreatment; H. pylori and gastric cancer, and H. pylori prevention/public health. Each group reviewed all published literature on H. pylori infection with special reference to the Indian scenario and prepared appropriate statements on different aspects for voting and consensus development. This consensus, which was produced through a modified Delphi process including two rounds of face-to-face meetings, reflects our current understanding and recommendations for the diagnosis and management of H. pylori infection. These consensus should serve as a reference for not only guiding treatment of H. pylori infection but also to guide future research on the subject.

Lifestyle interventions can reduce the risk of Barrett's esophagus: a systematic review and meta-analysis of 62 studies involving 250,157 participants

Background

Barrett's esophagus (BE) is a well‐established risk factor for esophageal adenocarcinoma. Our objective was to investigate the effectiveness of lifestyle interventions on BE risk.

Methods

We searched PubMed, Embase, and Web of Science up to 30 September 2020. The summary relative risks (RRs) and 95% confidence intervals (CIs) for the highest versus lowest categories of exposure were assessed. Analyses of subgroup, dose–response, sensitivity, and publication bias were conducted.

Results

Sixty‐two studies were included that involved more than 250,157 participants and 22,608 cases. Seven lifestyle factors were investigated: smoking, alcohol, body mass index (BMI), physical activity, sleep time, medication, and diet. We observed statistically significant increased BE risks for smoking (RR = 1.35, 95% CI = 1.16–1.57), alcohol intake (RR = 1.23, 95% CI = 1.13–1.34), body fatness (RR = 1.08, 95% CI = 1.03–1.13), less sleep time (RR = 1.76, 95% CI = 1.24–2.49), and proton pump inhibitors use (RR = 1.64, 95% CI = 1.17–2.29). Reduced risks of BE were found for aspirin (RR = 0.70, 95% CI = 0.58–0.84) and the intake of vitamin C (RR = 0.59, 95% CI = 0.44–0.80), folate (RR = 0.47, 95% CI = 0.31–0.71), and fiber (RR = 0.95, 95% CI = 0.93–0.97). The quality of most included studies was high and the subgroup analysis according to the quality score showed significant results (p < 0.05). There was no publication bias for smoking and alcohol. Although the analysis suggested significant evidence of publication bias for BMI, sensitivity analysis showed that the changes in the recalculated RRs were not significant.

Conclusions

The large meta‐analysis revealed that lifestyle modifications could reduce the risks of BE and, consequently, esophageal adenocarcinoma.

Dentists Are at a Higher Risk for Oral Helicobacter pylori Infection

Oral cavity has been taken as one of the major reservoirs for Helicobacter pylori, the bacteria responsible for gastric infection and cancers. Dentists are frequently exposed to saliva; thus, theoretically, they are at a higher risk for oral H. pylori infection. In the present study, to test this hypothesis and to find out the potential factors associated with the increased risk, a cross-sectional study was carried out on a large scale of dentists (N = 90) and nondentist controls (N = 110). By using nested polymerase chain reaction to amplify a specific DNA fragment of H. pylori, we found 7.27% of saliva samples from the nondentist group and 16.67% of saliva samples from the dentist group were oral H. pylori positive, and the difference between groups was statistically significant (χ² = 4.292, p = 0.038). Importantly, however, after stratifying enrolled subjects with factors which might interfere with the comparison of H. pylori detection rate between groups, we still observed a higher H. pylori frequency in the dentists than that in the controls in subgroups, including those with good individual hygiene, healthy lifestyle, and physical condition, as well as those living with families to be gastric disease free and not sharing meals with H. pylori-positive persons, respectively. Moreover, the frequency of clinical practice per week of the investigated dentists was closely associated with an oral H. pylori infection risk. Our data indicates that dentists are at a higher risk for H. pylori infection, and intensive attention needs to be paid on this issue.

Association Between Helicobacter pylori Infection and Short-segment/Long-segment Barrett's Esophagus in a Japanese Population: A Large Cross-Sectional Study

GOAL

The goal of this study was to investigate the relationship between Helicobacter pylori (H. pylori) infection and short-segment and long-segment Barrett's esophagus (SSBE and LSBE).

BACKGROUND

H. pylori infection is reported to be inversely associated with Barrett's esophagus (BE) in western countries. However, the impact of BE segment length on the association between BE and H. pylori infection has scarcely been investigated.

MATERIALS AND METHODS

The study subjects were 41,065 asymptomatic Japanese individuals who took medical surveys between October 2010 and September 2017. Using this large database of healthy Japanese subjects, we investigated the association between H. pylori infection and SSBE/LSBE. We used multivariable logistic regression analysis to estimate odds ratios (ORs) and 95% confidence intervals (CIs).

RESULTS

Among the study subjects, 36,615 were eligible for the analysis. H. pylori seropositivity was significantly associated with a lower rate of LSBE (OR: 0.42; 95% CI: 0.16-0.91) and a higher rate of SSBE (OR: 1.66; 95% CI: 1.56-1.78) after multivariate adjustment. In the subgroup analysis, H. pylori seropositivity was significantly associated with a high rate of SSBE in subjects without reflux esophagitis (RE) (OR: 1.73; 95% CI: 1.61-1.85). However, H. pylori seropositivity was not associated with SSBE in subjects with RE (OR: 1.07; 95% CI: 0.84-1.37).

CONCLUSION

In a Japanese population, H. pylori infection was inversely associated with LSBE but significantly associated with SSBE only in subjects without RE. H. pylori may be a risk factor for SSBE, especially in individuals without RE.

Proton Pump Inhibitors and Radiofrequency Ablation for Treatment of Barrett's Esophagus

Gastroesophageal Reflux Disease (GERD) is characterized by acid and bile reflux in the distal oesophagus, and this may cause the development of reflux esophagitis and Barrett's oesophagus (BE). The natural histological course of untreated BE is non-dysplastic or benign BE (ND), then lowgrade (LGD) and High-Grade Dysplastic (HGD) BE, with the expected increase in malignancy transfer to oesophagal adenocarcinoma (EAC). The gold standard for BE diagnostics involves high-resolution white-light endoscopy, followed by uniform endoscopy findings description (Prague classification) with biopsy performance according to Seattle protocol. The medical treatment of GERD and BE includes the use of proton pump inhibitors (PPIs) regarding symptoms control. It is noteworthy that long-term use of PPIs increases gastrin level, which can contribute to transfer from BE to EAC, as a result of its effects on the proliferation of BE epithelium. Endoscopy treatment includes a wide range of resection and ablative techniques, such as radio-frequency ablation (RFA), often concomitantly used in everyday endoscopy practice (multimodal therapy). RFA promotes mucosal necrosis of treated oesophagal region via high-frequency energy. Laparoscopic surgery, partial or total fundoplication, is reserved for PPIs and endoscopy indolent patients or in those with progressive disease. This review aims to explain distinct effects of PPIs and RFA modalities, illuminate certain aspects of molecular mechanisms involved, as well as the effects of their concomitant use regarding the treatment of BE and prevention of its transfer to EAC.

Protective Propensity of Race or Environmental Features in the Development of Barrett's Esophagus in African Americans - A Single Center Pilot Study

BACKGROUND AND STUDY AIMS

Barrett's Esophagus (BE) is a well-recognized pre-malignant condition. Previous data indicate histologically confirmed BE frequency varies by ethnicity in the United States. However, clinical factor assessment to explain this has only occurred in a veteran population to date. The study aim was to determine which clinical factors may be associated with the ethnic variation seen in histologically confirmed BE among a general population.

PATIENTS AND METHODS

The University of Florida-Jacksonville endoscopy database was searched for all cases of endoscopic BE from September 2002 to October 2012. Histologic BE was diagnosed only if salmon colored, columnar-appearing esophageal mucosa was seen at endoscopy and biopsy revealed intestinal metaplasia with Alcian blue-stained goblet cells. Data collected included: age/BMI at diagnosis, ethnicity, sex, GERD history, atypical manifestations, endoscopic BE length, presence of esophageal stricture/ulcer/hiatal hernia, presence/absence of dysplasia and medication use (aspirin/NSAIDs/statin/PPI).

RESULTS

Salmon colored esophageal mucosa was observed in 1105 of 15,564 patients (7.1%) with BE histologically confirmed in 249 of 1105 patients (23%). Ethnic distribution of histologic BE patients: 83% non-Hispanic white (nHw), 13% African American (AA) and 4% other. No difference was seen between groups with regard to BMI, GERD symptom/complications, BE length, and cigarette, alcohol or medication use.

CONCLUSION

BE occurs primarily in nHw in north Florida. This occurs despite similarities in GERD history, cigarette/alcohol use, medications prescribed and BMI. Molecular level investigation is necessary to explain this observed disparity between nHw and AA.

Helicobacter pylori Infection Is Associated With Reduced Risk of Barrett's Esophagus: An Analysis of the Barrett's and Esophageal Adenocarcinoma Consortium

OBJECTIVES

Epidemiological studies of Helicobacter pylori infection and risk of Barrett's esophagus (BE) have reported conflicting results. We examined the association between H. pylori infection and BE and sought to determine whether the association is mediated by gastroesophageal reflux disease (GERD) and to identify potential effect modifiers.

METHODS

We used individual level data from 1308 patients with BE (cases), 1388 population-based controls, and 1775 GERD controls in the Barrett's and Esophageal Adenocarcinoma Consortium (BEACON). We estimated study-specific odds ratios (ORs) and 95% CIs using multivariable logistic regression models and obtained summary risk estimates using a random-effects meta-analytic approach. We examined potential effect modification by waist-to-hip ratio (WHR), body mass index (BMI), and smoking status by conducting stratified analyses.

RESULTS

For comparisons with population-based controls, H. pylori infection was inversely associated with the risk of BE (adjusted OR = 0.44, 95% CI = 0.36-0.55), with no evidence of between-study heterogeneity (I² = 0%). A stronger inverse association between H. pylori and BE was observed among individuals with the CagA-positive strain (P for interaction = 0.017). We found no evidence of interaction between WHR, BMI, smoking status, and H. pylori infection on the risk of BE. There was no association between H. pylori infection and BE for comparisons with GERD controls (OR = 0.96, 95% CI = 0.67-1.37; I² = 48%).

CONCLUSIONS

This study provides the strongest evidence yet that H. pylori infection is strongly inversely associated with BE. This effect is probably mediated by a decrease in GERD in infected patients, since the protective effect disappears in patients with GERD symptoms.

Helicobacter pylori infection reduces the risk of Barrett's esophagus: A meta-analysis and systematic review

INTRODUCTION

The prevalence of Helicobacter pylori infection (HPI) has been decreasing in developed countries, with an increasing prevalence of Barrett's esophagus (BE) and esophageal adenocarcinoma (EAC) at the same time. The aim of our meta-analysis was to quantify the risk of BE in the context of HPI.

METHODS

A systematic search was conducted in 3 databases for studies on BE with data on prevalence of HPI from inception until December 2016. Odds ratios for BE in HPI were calculated by the random effects model with subgroup analyses for geographical location, presence of dysplasia in BE, and length of the BE segment.

RESULTS

Seventy-two studies were included in the meta-analysis, including 84 717 BE cases and 390 749 controls. The overall analysis showed that HPI reduces the risk of BE; OR = 0.68 (95% CI: 0.58-0.79, P < .001). Subgroup analyses revealed risk reduction in Asia OR = 0.53 (95% CI: 0.33-0.84, P = .007), Australia OR = 0.56 (95% CI: 0.39-0.80, P = .002), Europe OR = 0.77 (95% CI: 0.60-0.98, P = .035), and North-America OR = 0.59 (95% CI: 0.47-0.74, P < .001). The risk was significantly reduced for dysplastic BE, OR = 0.37 (95% CI: 0.26-0.51, P < .001) for non-dysplastic BE, OR = 0.51 (95% CI: 0.35-0.75, P = .001), and for long segment BE, OR = 0.25 (95% CI: 0.11-0.59, P = .001) in case of HPI.

CONCLUSIONS

This extensive meta-analysis provides additional evidence that HPI is associated with reduced risk of BE. Subgroup analyses confirmed that this risk reduction is independent of geographical location. HPI is associated with significantly lower risk of dysplastic, non-dysplastic, and long segment BE.

Helicobacter pylori induces caudal-type homeobox protein 2 and cyclooxygenase 2 expression by modulating microRNAs in esophageal epithelial cells

Dysregulation of microRNAs (miRNAs) has been linked to virulence factors of Helicobacter pylori. The role of H. pylori in esophageal disease has not been clearly defined. We previously reported that H. pylori esophageal colonization promotes the incidence of Barrett's esophagus and esophageal adenocarcinoma in vivo. Here, we studied the direct effects of H. pylori on the transformation of esophageal epithelial cells, with particular focus on whether H. pylori exerts its effects by modulating miRNAs and their downstream target genes. The normal human esophageal cell line HET‐1A was chronically exposed to H. pylori extract and/or acidified deoxycholic acid for up to 36 weeks. The miRNA profiles of the esophageal epithelial cells associated with H. pylori infection were determined by microarray analysis. We found that chronic H. pylori exposure promoted acidified deoxycholic acid‐induced morphological changes in HET‐1A cells, along with aberrant overexpression of intestinal metaplasia markers and tumorigenic factors, including caudal‐type homeobox protein 2 (CDX2), mucin 2, and cyclooxygenase 2 (COX2). Helicobacter pylori modified the miRNA profiles of esophageal epithelial cells, particularly aberrant silencing of miR‐212‐3p and miR‐361‐3p. Moreover, in biopsies from Barrett's esophagus patients, esophageal H. pylori colonization was associated with a significant decrease in miR‐212‐3p and miR‐361‐3p expression. Furthermore, we identified COX2 as a target of miR‐212‐3p, and CDX2 as a target of miR‐361‐3p. Helicobacter pylori infection of esophageal epithelial cells was associated with miRNA‐mediated upregulation of oncoprotein CDX2 and COX2. Our observations provide new evidence about the molecular mechanisms underlying the association between H. pylori infection and esophageal carcinogenesis.

Oesophageal cancer

Oesophageal cancer is the sixth most common cause of cancer-related death worldwide and is therefore a major global health challenge. The two major subtypes of oesophageal cancer are oesophageal squamous cell carcinoma (OSCC) and oesophageal adenocarcinoma (OAC), which are epidemiologically and biologically distinct. OSCC accounts for 90% of all cases of oesophageal cancer globally and is highly prevalent in the East, East Africa and South America. OAC is more common in developed countries than in developing countries. Preneoplastic lesions are identifiable for both OSCC and OAC; these are frequently amenable to endoscopic ablative therapies. Most patients with oesophageal cancer require extensive treatment, including chemotherapy, chemoradiotherapy and/or surgical resection. Patients with advanced or metastatic oesophageal cancer are treated with palliative chemotherapy; those who are human epidermal growth factor receptor 2 (HER2)-positive may also benefit from trastuzumab treatment. Immuno-oncology therapies have also shown promising early results in OSCC and OAC. In this Primer, we review state-of-the-art knowledge on the biology and treatment of oesophageal cancer, including screening, endoscopic ablative therapies and emerging molecular targets, and we discuss best practices in chemotherapy, chemoradiotherapy, surgery and the maintenance of patient quality of life.

Risk of histologic Barrett's esophagus between African Americans and non-Hispanic whites: A meta-analysis

Background

Barrett's esophagus (BE) is rare in African Americans (AA). However, the risk difference magnitude in histologic BE prevalence between AA and non-Hispanic whites (nHw) has not been quantified to date.

Objective

The objective of this article is to determine the degree of histologic BE risk difference between AA and nHw.

Methods

PubMed, Web of Science and EMBASE were searched for studies reporting histologic BE in AA/nHw for inclusion. Pooled odds ratios (ORs) with risk estimates of histologic BE occurrence between AA/nHw were calculated along with 95% confidence intervals (CIs). Forest plots were used to quantify heterogeneity. Funnel plots and the Cochrane Collaboration Risk of Bias tool were used to assess bias risk.

Results

Eight studies reported BE histologic confirmation in AA/nHw. Analysis demonstrated a nearly 400% increased histologic BE risk in nHw patients compared to AA (OR 3.949, 95% CI 3.069-5.082). In the model without the case-control study, histologic BE risk remained elevated at approximately 360% in nHw compared to AA (OR 3.618, 95% CI 2.769-4.726). Heterogeneity was not present in either model. Risk of bias was significant.

Conclusions

Histologic BE risk is elevated in nHw by 3.6-4 times compared to AA. Investigation into understanding any clinical, molecular or genetic mechanisms underlying this risk disparity is warranted.

Population screening and treatment of Helicobacter pylori infection

Helicobacter pylori is an important human pathogen, associated with a substantial burden from both malignant and non-malignant diseases. The bacterium is classed as a human carcinogen, being strongly linked with gastric cancer, the third most common cause of cancer death worldwide and is also associated with common conditions such as dyspepsia and peptic ulcer. Eradication of H. pylori reduces the incidence of gastric cancer and peptic ulcer, as well as the prevalence and costs of managing dyspepsia. Economic analyses suggest that eradication of H. pylori as a means of controlling gastric cancer is cost-effective in high-risk populations. Even in populations at low risk of gastric cancer, there might be other benefits arising from screening and treatment, owing to the effects on non-malignant upper gastrointestinal diseases. However, public health authorities have been slow to consider the benefits of population-based screening and treatment as a means of reducing the morbidity and mortality associated with the infection. There are also concerns about widespread use of eradication therapy, including antimicrobial resistance and a rise in the prevalence of diseases that are negatively associated with H. pylori, such as GERD, Barrett oesophagus, asthma and obesity. This Review summarizes these issues.

The Gastric Microbiome and Its Influence on Gastric Carcinogenesis: Current Knowledge and Ongoing Research

Gastric malignancies are a leading cause of cancer-related death worldwide. At least 2 microbial species are currently linked to carcinogenesis and the development of cancer within the human stomach. These include the bacterium Helicobacter pylori and the Epstein-Barr virus. In recent years, there has been increasing evidence that within the human gastrointestinal tract it is not only pathogenic microbes that impact human health but also the corresponding autochthonous microbial communities. This article reviews the gastrointestinal microbiome as it relates primarily to mechanisms of disease and carcinogenesis within the upper gastrointestinal tract.

The frequency of histologically confirmed Barrett's esophagus varies by the combination of ethnicity and gender

BACKGROUND

Barrett's esophagus (BE) is the primary risk factor for esophageal adenocarcinoma (EAC). Limited data exists regarding the frequency of histologically confirmed BE by both gender and ethnicity in the United States. The study aim was to determine whether the frequency of histologically confirmed BE varies by ethnicity and gender.

METHODS

The University of Florida-Jacksonville endoscopy database was reviewed for all cases of salmon colored esophageal mucosa from September 2002 to August 2007. Histologic BE was diagnosed only if salmon colored esophageal mucosa was seen endoscopically and biopsy confirmed intestinal metaplasia with goblet cells. Data collected included: age at diagnosis, self-reported ethnicity [non-Hispanic white (nHw) or African American (AA)], gender, procedure indication, gastroesophageal reflux disease (GERD) history, atypical manifestations, cigarette smoking, alcohol use, proton pump inhibitor (PPI) use, BE endoscopic length, absence/presence of hiatal hernia, stricture or ulcer, and absence/presence/grade of dysplasia.

RESULTS

Salmon colored esophageal mucosa was identified in 391/7,308 patients, distributed ethnically as 306 nHw and 85 AA. Histologic BE was confirmed in 111/391 patients with ethnic distribution of: 95 nHw and 16 AA. Histologically confirmed BE frequency varied both by gender and ethnicity with nHw males having the highest (42.3%) and AA females the lowest (12.3%). Histologically confirmed BE frequency differed significantly between nHw males and nHw/AA females only (P<0.005).

CONCLUSIONS

Histologically confirmed BE frequency varies by ethnicity and gender with nHw males having the highest frequency/risk and AA females the lowest. Investigation to improve understanding of the impact of race and gender in BE formation should be performed.

Risk Profiles for Barrett's Esophagus Differ between New and Prevalent, and Long- and Short-Segment Cases

Background

Previous studies on Barrett’s esophagus (BE) risk factors have had differing case definitions and control groups. The purpose of this study was to examine differences in risk factors between newly diagnosed vs. prevalent BE, long- vs. short-segment BE, and endoscopy-only BE without specialized intestinal metaplasia (SIM).

Methods

We conducted a cross-sectional study among eligible patients scheduled for elective esophagogastroduodenoscopy (EGD) and patients eligible for screening colonoscopy, recruited from primary care clinics at a Veterans Affairs center. All participants completed a survey on demographics, gastroesophageal reflux disease (GERD) symptoms and medication use prior to undergoing study EGD. We compared BE cases separately to two control groups: 503 primary care controls and 1353 endoscopy controls. Associations between risk factors and differing BE case definitions were evaluated with multivariate logistic regression models.

Results

For comparisons with primary care controls, early onset frequent GERD symptoms were more strongly associated with risk of long-segment BE (OR 19.9; 95% CI 7.96–49.7) than short-segment BE (OR 8.54; 95% CI 3.85–18.9). Likewise, the inverse association with H. pylori infection was stronger for long-segment BE (OR, 0.45; 95% CI, 0.26–0.79) than short-segment BE (OR, 0.71; 95% CI, 0.48–1.05). GERD symptoms and H. pylori infection was also more strongly associated with prevalent BE than newly diagnosed BE. Few differences were observed between BE cases and endoscopy controls. Endoscopy-only BE was associated with GERD symptoms (OR 2.25, 95% CI 1.32–3.85) and PPI/H2RA use (OR 4.44; 95% CI 2.61–7.54) but to a smaller degree than BE with SIM.

Conclusion

We found differences in the strength and profiles of risk factors for BE. The findings support that epidemiological studies of BE should make a distinction between long and short, new and prevalent, endoscopy-only and BE with SIM as well as type of controls.

Risk stratification for malignant progression in Barrett’s esophagus: Gender, age, duration and year of surveillance

AIM

To clarify risk based upon segment length, diagnostic histological findings, patient age and year of surveillance, duration of surveillance and gender.

METHODS

Patients registered with the United Kingdom Barrett’s Oesophagus Registry from 9 United Kingdom centers were included. The outcome measures were (1) development of all grades of dysplasia; (2) development of high-grade of dysplasia or adenocarcinoma; and (3) development of adenocarcinoma. Prevalent cases and subjects with < 1 year of follow-up were excluded. The covariates examined were segment length, previous biopsy findings, age at surveillance, duration of surveillance, year of surveillance and gender.

RESULTS

One thousand and one hundred thirty six patients were included (total 6474 patient-years). Fifty-four patients developed adenocarcinoma (0.83% per annum), 70 developed high-grade dysplasia/adenocarcinoma (1.1% per annum) and 190 developed any grade of dysplasia (3.5% per annum). High grade dysplasia and adenocarcinoma increased with age and duration of surveillance. The risk of low-grade dysplasia development was not dependent on age at surveillance. Segment length and previous biopsy findings were also significant factors for development of dysplasia and adenocarcinoma.

CONCLUSION

The risk of development of low-grade dysplasia is independent of age at surveillance, but high-grade dysplasia and adenocarcinoma were more commonly found at older age. Segment length and previous biopsy findings are also markers of risk. This study did not demonstrate stabilisation of the metaplastic segment with prolonged surveillance.

The oesophageal microbiome: an unexplored link in obesity-associated oesophageal adenocarcinoma

The influence of diets rich in saturated fats and simple sugars on the intestinal microbiota plays a central role in obesity. Being overweight or obese predisposes individuals to several diseases including oesophageal adenocarcinoma (OAC), which develops through a cascade of events starting with gastro-oesophageal reflux disease, progressing to Barrett's oesophagus (BO), and then OAC. A range of mechanisms for the increased risk of OAC in obese individuals have been proposed; however, a role for the oesophageal microbiota has been largely ignored. This is despite the fact that it is clear that the composition of the oesophageal microbiota shifts with the development of OAC. Given the well-established impact that unhealthy diets have on the intestinal microbiota, it is plausible that exposure to unhealthy foods, and the ensuing obesity, would result in an imbalance in the oesophageal microbiota. It is also likely that these changes may mimic the changes observed in the intestinal microbiota (i.e. increase in short-chain fatty acid (SCFA) producers and bile acid biosynthesis). The modulation of SCFAs and bile acids in the oesophagus by diet could promote the transdifferentiation from squamous to intestinal-like columnar cells observed in BO, given that intestinal cells proliferate in the presence of SCFAs.

Determination of risk for Barrett's esophagus and esophageal adenocarcinoma

PURPOSE OF REVIEW

The incidence of esophageal adenocarcinoma and its precursor, Barrett's esophagus, have increased greatly over the past 40 years and continue to rise. This report summarizes the most recent data on the risk factors for Barrett's esophagus and esophageal adenocarcinoma.

RECENT FINDINGS

Other factors, highly correlated with increasing trends for obesity, are the dominant driver of the increase in incidence of esophageal adenocarcinoma, interacting with gastroesophageal reflux disease symptoms. Abdominal obesity, independently of gastroesophageal reflux disease symptoms, is associated with increased risk of Barrett's esophagus and this association is likely mediated by high levels of leptin and insulin. Use of aspirin, nonsteroidal anti-inflammatory drugs, statins, and proton pump inhibitors are associated with a reduced risk of Barrett's esophagus as well as lower risk of neoplastic progression in patients with Barrett's esophagus. An increasing number of genetic loci have been associated with risk of Barrett's esophagus and esophageal adenocarcinoma.

SUMMARY

Recent advances in identifying risk factors and reporting of more precise estimates of effect for the main risk factors will positively impact clinical risk stratification efforts for Barrett's esophagus and esophageal adenocarcinoma. Large pooling studies are underway to derive and validate reliable clinical risk models.

Gastric Helicobacter pylori Infection Affects Local and Distant Microbial Populations and Host Responses

Helicobacter pylori is a late-in-life human pathogen with potential early-life benefits. Although H. pylori is disappearing from the human population, little is known about the influence of H. pylori on the host's microbiota and immunity. Studying the interactions of H. pylori with murine hosts over 6 months, we found stable colonization accompanied by gastric histologic and antibody responses. Analysis of gastric and pulmonary tissues revealed increased expression of multiple immune response genes, conserved across mice and over time in the stomach and more transiently in the lungs. Moreover, H. pylori infection led to significantly different population structures in both the gastric and intestinal microbiota. These studies indicate that H. pylori influences the microbiota and host immune responses not only locally in the stomach, but distantly as well, affecting important target organs.

Primary esophageal adenocarcinoma with distant metastasis to the skeletal muscle

Hematogenous metastasis of esophageal adenocarcinoma to the skeletal muscle is uncommon. We report a rare case of esophageal adenocarcinoma with metastasis to the skeletal muscle. During pretherapeutic examination, a painful mass was detected in the left thigh of a 49-year-old man. Endoscopic biopsy identified poorly differentiated, advanced esophageal adenocarcinoma. Computed tomography (CT) revealed wall thickening in the distal esophagus. Two enlarged lymph nodes were detected--the middle thoracic paraesophageal lymph node in the mediastinum and the right cardiac lymph node. (18)F-fluorodeoxyglucose (FDG) positron emission tomography demonstrated left thigh metastasis, which had not been detected by CT 3 weeks previously, with increased accumulation of FDG. Therefore, ultrasound-guided core-needle biopsy was performed. Histologic and immunohistochemical findings supported a diagnosis of poorly differentiated adenocarcinoma. The final diagnosis was primary esophageal adenocarcinoma with distant metastasis to the skeletal (left thigh) muscle. The rate of disease progression in this case emphasizes the malignant potential of esophageal adenocarcinoma. A few cases of skeletal metastasis from advanced esophageal adenocarcinoma have been previously reported. However, rapid metastasis to a distant skeletal muscle with no other hematogenous metastasis is quite rare. Early detection and rapid treatment are especially important in cases of esophageal adenocarcinoma.

African American ethnicity is not associated with development of Barrett's oesophagus after erosive oesophagitis

BACKGROUND

Barrett's oesophagus is the primary risk factor for oesophageal adenocarcinoma; erosive oesophagitis is considered an intermediate step with Barrett's oesophagus development potential upon healing. Barrett's oesophagus occurs in 9-19% following erosive oesophagitis but minimal data exists in African Americans. The study aim was to determine if ethnicity is associated with Barrett's oesophagus formation following erosive oesophagitis.

METHODS

Retrospective review of endoscopies from September 2007 to December 2012 was performed. Inclusion criteria were erosive oesophagitis on index endoscopy, repeat endoscopy ≥6 weeks later and non-Hispanic white or African American ethnicity. Barrett's oesophagus frequency following erosive oesophagitis by ethnicity was compared.

RESULTS

A total of 14,303 patients underwent endoscopy during the study period; 1636 had erosive oesophagitis. Repeat endoscopy was performed on 125 non-Hispanic white or African American patients ≥6 weeks from the index procedure. Barrett's oesophagus occurred in 8% of non-Hispanic whites while no African American developed it on repeat endoscopy following erosive oesophagitis (p=0.029). No significant difference was seen between ethnic groups in any clinical parameter assessed.

CONCLUSIONS

African American ethnicity appears to result in decreased Barrett's oesophagus formation following erosive oesophagitis. Further investigation to demonstrate factors resulting in decreased Barrett's oesophagus formation among African Americans should be performed.

Australian clinical practice guidelines for the diagnosis and management of Barrett's esophagus and early esophageal adenocarcinoma

Barrett's esophagus (BE), a common condition, is the only known precursor to esophageal adenocarcinoma (EAC). There is uncertainty about the best way to manage BE as most people with BE never develop EAC and most patients diagnosed with EAC have no preceding diagnosis of BE. Moreover, there have been recent advances in knowledge and practice about the management of BE and early EAC. To aid clinical decision making in this rapidly moving field, Cancer Council Australia convened an expert working party to identify pertinent clinical questions. The questions covered a wide range of topics including endoscopic and histological definitions of BE and early EAC; prevalence, incidence, natural history, and risk factors for BE; and methods for managing BE and early EAC. The latter considered modification of lifestyle factors; screening and surveillance strategies; and medical, endoscopic, and surgical interventions. To answer each question, the working party systematically reviewed the literature and developed a set of recommendations through consensus. Evidence underpinning each recommendation was rated according to quality and applicability.

Update on metastatic gastric and esophageal cancers

Cancers of the stomach and esophagus are among the most challenging cancers of the GI tract to treat, associated with poor median survivals for metastatic disease and significant, sometimes prolonged, deteriorations in patient performance status as the diseases progress. However, in the past decade, we have begun to better understand disease biology and carcinogenesis, leading to the identification of subtypes of these diseases. There is also an increasing awareness of the global heterogeneity of disease and its impact on drug development. Our improved understanding of the molecular underpinnings of gastric and esophageal cancers has been accompanied with the development of novel therapeutic strategies. Recent actively investigated targets in this disease include human epidermal growth factor receptor 2, angiogenesis, MET, and immune checkpoint inhibition, with approvals of two new targeted agents, trastuzumab and ramucirumab. Improvements in our ability to deliver cytotoxic therapy, which is better tolerated and allows patients an opportunity to benefit from second- and more advanced lines of therapy, have also been observed. In this review, the current state-of-the-art management of advanced and metastatic gastric and esophageal adenocarcinomas, specifically highlighting the development of targeted therapies in these diseases, is described.

Aspirin and nonsteroidal anti-inflammatory drug use and the risk of Barrett's esophagus

BACKGROUND

The use of aspirin and nonsteroidal anti-inflammatory drugs (NSAIDs) may decrease the risk of esophageal adenocarcinoma; however, it is unknown where these agents may act in the proposed pathway from normal mucosa to Barrett's esophagus to esophageal adenocarcinoma.

AIM

The aim of the study was to evaluate the association between aspirin and NSAID use and Barrett's esophagus in a case-control study within a large community-based population.

METHODS

We conducted a case-control study of aspirin/NSAID use and Barrett's esophagus within the Kaiser Permanente Northern California population. Cases had a new diagnosis of Barrett's esophagus between October 2002 and September 2005; controls were members without a diagnosis of Barrett's esophagus.

RESULTS

Persons with Barrett's esophagus were less likely to use aspirin than population controls [odds ratio (OR) 0.59, 95 % confidence interval (CI) 0.39-0.87]; a stronger association was found among cases and controls with reflux symptoms (OR 0.49, 95 % CI 0.32-0.75; p value interaction = 0.004). Similar associations were found with the use of either aspirin and/or non-aspirin NSAIDs (OR 0.53, 95 % CI 0.35-0.81), although NSAID use alone was not significantly associated with Barrett's esophagus (OR 0.74, 95 % CI 0.47-1.16). The strength of the association was highest among persons with at least moderate-to-high total medication intake.

CONCLUSIONS

Regular use of aspirin or NSAIDs was associated with a decreased risk of Barrett's esophagus, particularly among persons with gastroesophageal reflux disease symptoms. These findings have implications for chemoprevention, as some of the previously described protective association between aspirin/NSAIDs and esophageal adenocarcinoma may be explained by events that occur prior to the development of Barrett's esophagus.

Chemoradiation in oesophageal cancer

Oesophageal cancer is the 8th most common cancer worldwide, and has significant mortality and morbidity rates. The two most common histological types, squamous cell carcinoma and adenocarcinoma, have different localizations, distinctive risk factors, and molecular mechanisms. Survival for patients with locoregional oesophageal cancer is poor when treated with surgery only, with 5-year survival less than 10-15%. Radiation therapy has limited efficacy when given alone. Concurrent chemoradiation improves local-regional control and facilitates margin-free resection when delivered preoperatively. Chemoradiation prolongs survival when given as definitive treatment or combined with surgery. Neoadjuvant chemoradiation also reduces risk of distant recurrence. To date, there is no data supporting the addition of targeted therapy to concurrent chemoradiation. Understanding molecular pathways regulating both radiosensitivity and tumorigenesis/invasion may lead to the discovery of new targeted agents, improving outcome of chemoradiation in terms of both locoregional and systemic control, ultimately resulting in prolonged survival.

Helicobacter pylori Infection in Gastroesophageal Reflux Disease in the Asian Countries

Helicobacter pylori infection, a common infection in many countries, is related to the clinical course of upper gastrointestinal diseases. Gastroesophageal reflux disease (GERD) is a common esophageal disease in Western countries and its prevalence is increasing in Asian countries. The pathophysiology of GERD is multifactorial. Although no single factor has been isolated as the cause of GERD, a negative association between the prevalence of H. pylori and the severity of GERD, including Barrett's esophagus, has been demonstrated in epidemiological studies. The high prevalence of H. pylori infection affects the incidence of GERD in Asian countries. In the subjects with East Asian CagA-positive strains, acid injury may be minimized by hypochlorhydria from pangastritis and gastric atrophy. Additionally, host genetic factors may affect the development of GERD. The interactions between genetic factors and the virulence of H. pylori infection may be the reason for the low prevalence of GERD in Asian countries. H. pylori eradication is not considered pivotal in GERD exacerbation based on evidence from Western studies. A recent meta-analysis demonstrated that eradication therapy of H. pylori was related to a higher risk of developing de novo GERD in Asian studies. H. pylori infection remains an inconclusive and important issue in GERD in Asian countries.

Risk of esophageal adenocarcinoma decreases with height, based on consortium analysis and confirmed by Mendelian randomization

BACKGROUND & AIMS

Risks for some cancers increase with height. We investigated the relationship between height and risk of esophageal adenocarcinoma (EAC) and its precursor, Barrett's esophagus (BE).

METHODS

We analyzed epidemiologic and genome-wide genomic data from individuals of European ancestry in the Barrett's and Esophageal Adenocarcinoma Consortium, from 999 cases of EAC, 2061 cases of BE, and 2168 population controls. Multivariable logistic regression was used to estimate odds ratios (OR) and 95% confidence intervals (95% CI) for associations between height and risks of EAC and BE. We performed a Mendelian randomization analysis to estimate an unconfounded effect of height on EAC and BE using a genetic risk score derived from 243 genetic variants associated with height as an instrumental variable.

RESULTS

Height was associated inversely with EAC (per 10-cm increase in height: OR, 0.70; 95% CI, 0.62-0.79 for men and OR, 0.57; 95% CI 0.40-0.80 for women) and BE (per 10-cm increase in height: OR, 0.69; 95% CI, 0.62-0.77 for men and OR, 0.61; 95% CI, 0.48-0.77 for women). The risk estimates were consistent across strata of age, education level, smoking, gastroesophageal reflux symptoms, body mass index, and weight. Mendelian randomization analysis yielded results quantitatively similar to those from the conventional epidemiologic analysis.

CONCLUSIONS

Height is associated inversely with risks of EAC and BE. Results from the Mendelian randomization study showed that the inverse association observed did not result from confounding factors. Mechanistic studies of the effect of height on EAC and BE are warranted; height could have utility in clinical risk stratification.

Helicobacter pylori gastritis in HIV-infected patients: a review

BACKGROUND

The risk factors for acquiring Helicobacter pylori and Human Immunodeficiency Virus (HIV) infections are different: H. pylori is transmitted by gastro- or fecal-oral routes and is associated with low socioeconomic conditions, while HIV is transmitted through sexual intercourse, infected body fluids, and transplacentally. If the host responses to these infections were independent, the prevalence of H. pylori should be similar in HIV-infected and non-infected patients. Yet, several studies have detected a lower prevalence of H. pylori in patients with HIV infection, whereas other studies found either no differences or greater rates of H. pylori infection in HIV-positive subjects.

OBJECTIVE

To review studies that addressed the issue of these two simultaneous infections and attempt to determine whether reliable conclusions can be drawn from this corpus of often contrasting evidence.

METHODS

Electronic literature search for relevant publications, followed by manual search of additional citations from extracted articles.

RESULTS

The initial search yielded 44 publications; after excluding case reports, reviews, narrowly focused articles, and duplicate reports, there remained 29 articles, which are the corpus of this review. With one exception, all studies reported higher rates of H. pylori infection in HIV-negative subjects. Five studies also examined the CD4 lymphocyte counts and found an inverse correlation between the degree of immunosuppression and the prevalence of active H. pylori infection.

CONCLUSIONS

Current evidence suggests that it is likely that H. pylori needs a functional immune system to successfully and persistently colonize the human gastric mucosa.

Exploring the recent trend in esophageal adenocarcinoma incidence and mortality using comparative simulation modeling

BACKGROUND

The incidence of esophageal adenocarcinoma (EAC) has increased five-fold in the United States since 1975. The aim of our study was to estimate future U.S. EAC incidence and mortality and to shed light on the potential drivers in the disease process that are conduits for the dramatic increase in EAC incidence.

METHODS

A consortium of three research groups calibrated independent mathematical models to clinical and epidemiologic data including EAC incidence from the Surveillance, Epidemiology, and End Results (SEER 9) registry from 1975 to 2010. We then used a comparative modeling approach to project EAC incidence and mortality to year 2030.

RESULTS

Importantly, all three models identified birth cohort trends affecting cancer progression as a major driver of the observed increases in EAC incidence and mortality. All models predict that incidence and mortality rates will continue to increase until 2030 but with a plateauing trend for recent male cohorts. The predicted ranges of incidence and mortality rates (cases per 100,000 person years) in 2030 are 8.4 to 10.1 and 5.4 to 7.4, respectively, for males, and 1.3 to 1.8 and 0.9 to 1.2 for females. Estimates of cumulative cause-specific EAC deaths between both sexes for years 2011 to 2030 range between 142,300 and 186,298, almost double the number of deaths in the past 20 years.

CONCLUSIONS

Through comparative modeling, the projected increases in EAC cases and deaths represent a critical public health concern that warrants attention from cancer control planners to prepare potential interventions.

IMPACT

Quantifying this burden of disease will aid health policy makers to plan appropriate cancer control measures. Cancer Epidemiol Biomarkers Prev; 23(6); 997-1006. ©2014 AACR.

Risk factors associated with Barrett’s epithelial dysplasia

AIM: To elucidate risk factors associated with dysplasia of short-segment Barrett’s esophagus (BE).

METHODS: A total of 151 BE patients who underwent endoscopic examination from 2004 to 2008 in Aoyama Hospital, Tokyo Women’s Medical University, Japan and whose diagnosis was confirmed from biopsy specimens were enrolled in the study. BE was diagnosed based on endoscopic findings of gastric-appearing mucosa or apparent columnar-lined esophagus proximal to the esophagogastric junction. Dysplasia was classified into three grades - mild, moderate and severe - according to the guidelines of the Vienna Classification System for gastrointestinal epithelial neoplasia. Anthropometric and biochemical data were analyzed to identify risk factors for BE dysplasia. The prevalence of Helicobacter pylori (H. pylori) infection and the expression of p53 by immunohistological staining were also investigated.

RESULTS: Histological examination classified patients into three types: specialized columnar epithelium (SCE) (n = 65); junctional (n = 38); and gastric fundic (n = 48). The incidence of dysplasia or adenocarcinoma from BE of the SCE type was significantly higher than that of the other two types (P < 0.01). The univariate analysis revealed that sex, H. pylori infection, body weight, p53 overexpression, and low diastolic blood pressure (BP) were associated with BE dysplasia. In contrast, body mass index, waist circumference, metabolic syndrome complications, and variables related to glucose or lipid metabolism were not associated with dysplasia. Multivariate logistic analysis showed that overexpression of p53 [odds ratio (OR) = 13.1, P = 0.004], H. pylori infection (OR = 0.19, P = 0.066), and diastolic BP (OR = 0.87, P = 0.021) were independent risk factors for epithelial dysplasia in BE patients with the SCE type.

CONCLUSION: Overexpression of p53 is a risk factor for dysplasia of BE, however, H. pylori infection and diastolic BP inversely associated with BE dysplasia might be protective.

Review article: bacteria and pathogenesis of disease in the upper gastrointestinal tract--beyond the era of Helicobacter pylori

BACKGROUND

Study of the upper gastrointestinal microbiome has shown that other bacteria besides Helicobacter pylori flourish despite the hostile environment. Whilst H. pylori is the most studied bacteria in this region with a defined role in inflammation and neoplasia, it is apparent that other bacteria may contribute to UGI disease.

AIM

To review current knowledge of bacteria inhabiting the oesophagus, stomach and duodenum.

METHODS

Published studies on the upper gastrointestinal microbiome (extracted from PubMed during the last 20 years).

RESULTS

The stomach is a hostile environment for bacteria; however, recent studies categorising the microbiota have shown surprising results. Helicobacter pylori has been intensively studied since 1984 and recent sequencing analysis of other gastric microbiota shows that H. pylori is not alone. Composition can be influenced by acid suppression, gastritis and abundance of H. pylori. Eradication of H. pylori, whilst decreasing gastric cancer is associated with an increase in asthma, reflux and obesity. A future approach may be to selectively eradicate bacteria which predispose to inflammation and cancer as opposed to a comprehensive knockout policy. In the oesophagus, viridans streptococci are the most common bacteria influenced by both oral and gastric bacteria. Oesophagitis and Barrett's oesophagus are characterised by a significant decrease in Gram-positive bacteria and an increase in Gram-negative bacteria. An inverse association of H. pylori and oesophageal adenocarcinoma is described. The duodenal microbiome has been shown to influence small intestinal bacterial overgrowth, irritable bowel syndrome and coeliac disease. The numbers of bacteria recoverable by culture are variable in the stomach mucosa and gastric juice, typically 10(2) -10(4) colony-forming units (CFU)/g or mL and in the oesophagus, up to 10(4) bacteria per mm(2) mucosal surface. In the small bowel, in health, 10(3) CFU/mL are normal.

CONCLUSION

This review highlights current knowledge of upper gastrointestinal bacteria and associations with disease.

Vegetable, fruit and nitrate intake in relation to the risk of Barrett's oesophagus in a large Dutch cohort

There are few epidemiological data on the dietary risk factors of Barrett's oesophagus, a precursor of oesophageal adenocarcinoma. The present study investigated the association between vegetable, fruit and nitrate intake and Barrett's oesophagus risk in a large prospective cohort. The Netherlands Cohort Study recruited 120,852 individuals aged 55-69 years in 1986. Vegetable and fruit intake was assessed using a 150-item FFQ, and nitrate intake from dietary sources and drinking water was determined. After 16.3 years of follow-up, 433 cases (241 men and 192 women) of Barrett's oesophagus with specialised intestinal metaplasia and 3717 subcohort members were analysed in a case-cohort design using Cox proportional hazards models while adjusting for potential confounders. Men exhibited a lower risk of Barrett's oesophagus in the highest v. the lowest quintile of total (multivariable-adjusted hazard ratio (HR): 0.66, 95% CI 0.43, 1.01), raw (HR 0.63, 95% CI 0.40, 0.99), raw leafy (HR 0.55, 95% CI 0.36, 0.86) and Brassica (HR 0.64, 95% CI 0.41, 1.00) vegetable intake. No association was found for other vegetable groups and fruits. No significant associations were found between vegetable and fruit intake and Barrett's oesophagus risk among women. Total nitrate intake was inversely associated with Barrett's disease risk in men (HR 0.50, 95% CI 0.25, 0.99) and positively associated with it in women (HR 3.77, 95% CI 1.68, 8.45) (P for interaction = 0.04). These results suggest that vegetable intake may contribute to the prevention of Barrett's oesophagus. The possible differential effect in men and women should be evaluated further.

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.

Genomics, the origins of agriculture, and our changing microbe-scape: time to revisit some old tales and tell some new ones

Though agriculture is often viewed as one of humanity's crowning achievements, skeletal evidence indicates that dependence on domesticated plants and animals was accompanied by an increase in infectious disease. Scientists have proposed that many important infections emerged in the period following the advent of agriculture, as a result of newly dense populations and novel proximity to domestic animals that served as reservoirs for novel pathogens. Here, we review genomic evidence regarding pathogen origins, analyzing these data using the epidemiological transition framework. Genetic information has forced us to reconsider how and when many important pathogens emerged; it appears that a number of infections thought to result from contact with domesticated animals arose much earlier than agriculture was adopted. We also consider the broader effect of agriculture upon the microbiome, exploring potential consequences for human health. We end by discussing the changes in the human microbe-scape we are likely to see in the future.

Genome-wide association study identifies common variants in SLC39A6 associated with length of survival in esophageal squamous-cell carcinoma

We conducted a genome-wide scan of SNPs to identify variants associated with length of survival in 1,331 individuals with esophageal squamous-cell carcinoma (ESCC), with associations validated in 2 independent sets including 1,962 individuals with this cancer. We identified rs1050631 in SLC39A6 as associated with the survival times of affected individuals, with the hazard ratio for death from ESCC in the combined sample being 1.30 (95% confidence interval (CI) = 1.19-1.43; P = 3.77 × 10(-8)). rs7242481, located in the 5' UTR of SLC39A6, disturbs a transcriptional repressor binding site and results in upregulation of SLC39A6 expression. Immunohistochemical staining of ESCC tissues showed that higher expression of SLC39A6 protein was correlated with shorter length of survival in individuals with advanced ESCC (P = 0.013). Knockdown of SLC39A6 expression suppressed proliferation and invasion in ESCC cells. These results suggest that SLC39A6 has an important role in the prognosis of ESCC and may be a potential therapeutic target.

The effect of Helicobacter pylori on gastroesophageal reflux disease

These investigators found no significant evidence suggesting a potential role of Helicobacter pylori infection in the development of erosive esophagitis.

Background and Objectives:

Helicobacter pylori infection represents one of the most common and medically prominent infections worldwide. Gastroesophageal reflux disease (GERD) has a multifactorial etiology. The nature of the relationship between Helicobacter pylori infection (HP) and reflux esophagitis is still not clear. This study is designed to find the influence of HP on GERD.

Patients and Methods:

The study was conducted retrospectively at Sakarya Newcity Hospital between January 2006 and January 2009. Data were collected on patient's age, sex, weight, the grade of GERD and the severity of HP.

Results:

There were 1,307 women and 1,135 men in this review with a mean age of 39,54 (range, 17 to 70) years. Helicobacter pylori positive (1 to 3 severity) was frequently seen in patients with GERD. A statistically significant relationship was found between HP positivity and the grade of GERD. The Helicobacter pylori infection (1 to 3 severity) was found in 1,437 (82.5%) of patients with GERD in our series.

Conclusions:

Controversy still exists about the association between GERD and HP infection. Based on our findings, significant evidence suggests the potential role of HP infection in the development of GERD. Also, the current data provide sufficient evidence to define the relationship between GERD and HP infection.

The incidence of esophageal adenocarcinoma continues to rise: analysis of period and birth cohort effects on recent trends

BACKGROUND

During the past four decades, the incidence of esophageal adenocarcinoma (EAC) has increased markedly in Western populations. Recent reports have suggested that the rate of increase has slowed or plateaued.

PATIENTS AND METHODS

Using data from cancer registries in Australia, the United States and Sweden, we examined incidence trends for esophageal and gastric cardia tumors between 1984 and 2008 using joinpoint analyses and age-period-cohort models.

RESULTS

EAC incidence continues to undergo statistically significant annual increases in Australia and the United States, although the rate of increase has slowed. Among men, incidence increased annually by 2.2% [95% confidence interval (CI) 1.5% to 2.9%] between 1994 and 2008 in Australia and 1.5% (95% CI 0.2% to 2.8%) between 1998 and 2008 in the United States. EAC incidence among men remained unchanged in Sweden between 2001 and 2008 (P = 0.52). EAC incidence among women showed significant linear increases between 1984 and 2008. Age-period-cohort models suggested strong effects for both period and birth cohort on EAC incidence in Australia and the United States, and a strong period effect for Sweden.

CONCLUSIONS

EAC incidence continues to increase in Australia and the United States. The continued increases, even among more recent birth cohorts, suggest that EAC incidence will continue to rise during coming decades.

Current status and future perspectives on the etiology of esophageal adenocarcinoma

Esophageal adenocarcinoma is the most common type of esophageal cancer in most Western countries and is an important contributor to overall cancer mortality. Most cases of esophageal adenocarcinoma are believed to arise from Barrett’s esophagus. Esophageal adenocarcinoma occurs more frequently in white men over 50 years old, as well as in people with frequent symptoms of gastroesophageal reflux, in smokers and in people who are obese. Higher consumption of fruit and vegetables, use of non-steroidal anti-inflammatory drugs, and infection with Helicobacter pylori have all been shown to reduce the risk of esophageal adenocarcinoma. Here, we review the epidemiological evidence for the major risk factors of esophageal adenocarcinoma and also discuss perspectives for future research.