Helicobacter pylori infection and Barrett's esophagus: a systematic review and meta-analysis

Extracellular vesicles and endothelial dysfunction in infectious diseases

Cardiovascular diseases (CVDs) remain the leading cause of mortality and morbidity globally. Studies have shown that infections especially bacteraemia and sepsis are associated with increased risks for endothelial dysfunction and related CVDs including atherosclerosis. Extracellular vesicles (EVs) are small, sealed membrane-derived structures that are released into body fluids and blood from cells and/or microbes and are critically involved in a variety of important cell functions and disease development, including intercellular communications, immune responses and inflammation. It is known that EVs-mediated mechanism(s) is important in the development of endothelial dysfunction in infections with a diverse spectrum of microorganisms including Escherichia coli, Candida albicans, SARS-CoV-2 (the virus for COVID-19) and Helicobacter pylori. H. pylori infection is one of the most common infections globally. During H. pylori infection, EVs can carry H. pylori components, such as lipopolysaccharide, cytotoxin-associated gene A, or vacuolating cytotoxin A, and transfer these substances into endothelial cells, triggering inflammatory responses and endothelial dysfunction. This review is to illustrate the important role of EVs in the pathogenesis of infectious diseases, and the development of endothelial dysfunction in infectious diseases especially H. pylori infection, and to discuss the potential mechanisms and clinical implications.

Helicobacter pylori infection in Xinjiang Uyghur Autonomous Region: Prevalence and analysis of related factors

BACKGROUND

14C urea breath test (14C UBT) and immunohistochemical staining (IHC) are widely used for detection Helicobacter pylori (H. pylori) infection with different sensitivity, and there is a difference in H. pylori infection rate in Uyghur and Han ethnic groups. Both need large cohort studies to evaluate the differences more accurately.

AIM

To analyze the difference between 14C UBT and IHC for H. pylori detection in Xinjiang Uyghur Autonomous Region and the difference between Uyghur and Han populations.

METHODS

There were 3944 cases of H. pylori infection detected by both IHC and 14C UBT at the same time (interval < 1 wk, with sampling site including gastric antrum, selected from 5747 patients). We compared the sensitivity of 14C UBT and IHC. We also compared 555 pairs of Han/Uyghur cases (completely matched for gender and age) for their H. pylori infection rates. The overall H. pylori infection rate of all 5747 cases and the correlation with other clinicopathological data were also further analyzed. SPSS V23.0 software was used for statistical analysis.

RESULTS

The sensitivity was 94.9% for 14C UBT and 65.1% for IHC, which was a significant difference (n = 3944, P < 0.001). However, among those cases negative for H. pylori by 14C UBT (detection value ≤ 100), 4.8% were positive by IHC. Combining both methods, the overall H. pylori infection rate was 48.6% (n = 5747), and differences in gender, age group, ethnicity and region of residence significantly affected the H. pylori positive rates. According to age group (Han/Uyghur), the positive rates were ≤ 30 years (62.2%/100.0%), 31-40 years (45.2%/85.7%), 41-50 years (47.2%/79.2%), 51-60 years (44.6%/76.1%), 61-70 years (40.9%/68.2%), 71-80 years (41.7%/54.1%) and ≥ 81 years (42.9%/NA). The H. pylori infection rates of Han/Uyghur paired cases were 41.4% and 73.3%, which was a significant difference (P < 0.001) (555 pairs). H. pylori positivity was significantly related to moderate-severe grade 2-3 chronic/active gastritis and intestinal metaplasia (all P < 0.05).

CONCLUSION

The sensitivity of 14C UBT was significantly higher, but combined application can still increase the accuracy. The prevention H. pylori should be emphasized for Uygur and young people.

Association of Barrett's esophagus with Helicobacter pylori infection: a meta-analysis

Background and Aims:

Barrett’s esophagus (BE) is the only recognized precursor for esophageal adenocarcinoma. Helicobacter pylori (H. pylori) infection is a major contributing factor towards upper gastrointestinal diseases, but its relationship with BE remains controversial. Some previous studies suggested that H. pylori infection negatively correlated with BE, while others did not. This may be attributed to the difference in the selection of control groups among studies. The present meta-analysis aims to clarify their association by combining all available data from well-designed studies.

Methods:

The PubMed, EMBASE, and Cochrane Library databases were searched. Odds ratios (ORs) with 95% confidence intervals (CIs) were pooled by a random-effects model. Heterogeneity was evaluated using the Cochran’s Q test and I² statistics. Meta-regression, subgroup, and leave-one-out sensitivity analyses were employed to explore the sources of heterogeneity.

Results:

Twenty-four studies with 1,354,369 participants were included. Meta-analysis found that patients with BE had a significantly lower prevalence of H. pylori infection than those without (OR = 0.53, 95% CI = 0.45–0.64; p < 0.001). The heterogeneity was statistically significant (I² = 79%; p < 0.001). Meta-regression, subgroup, and leave-one-out sensitivity analyses did not find any source of heterogeneity. Meta-analysis of 7 studies demonstrated that CagA-positive H. pylori infection inversely correlated with BE (OR = 0.25, 95% CI = 0.15–0.44; p = 0.000), but not CagA-negative H. pylori infection (OR = 1.22, 95% CI = 0.90–1.67; p = 0.206). Meta-analysis of 4 studies also demonstrated that H. pylori infection inversely correlated with LSBE (OR = 0.39, 95% CI = 0.18–0.86; p = 0.019), but not SSBE (OR = 0.73, 95% CI = 0.30–1.77; p = 0.484).

Conclusion:

H. pylori infection negatively correlates with BE. More experimental studies should be necessary to elucidate the potential mechanisms in future.

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.

Systematic review with meta-analysis: association of Helicobacter pylori infection with gastro-oesophageal reflux and its complications

BACKGROUND

Conflicting results exist on the association between Helicobacter pylori infection and gastro-oesophageal reflux (GOR), and its complications, such as erosive oesophagitis (EO) and Barrett's oesophagus (BO).

AIMS

To explore the association of H. pylori infection with GOR symptoms and their complications METHODS: We searched Embase, PubMed, Web of Science and Scopus databases through December 2020 for relevant articles. Regarding the association between H. pylori and GOR symptoms (heartburn, regurgitation or reflux), we included observational studies comparing the prevalence of GOR symptoms between H. pylori-positive and -negative individuals. Concerning the association between H. pylori and complications of GOR, we included studies comparing the prevalence of EO or BO between H. pylori-positive and -negative individuals.

RESULTS

In total, 36 papers were eligible. Based on seven cross-sectional surveys, H. pylori infection was associated with a lower odds of GOR symptoms (odds ratio [OR] 0.74, 95% confidence interval [CI] 0.61-0.90). However, in four case-control studies, H. pylori infection was not associated with odds of GOR symptoms (OR 1.10, 95% CI 0.85-0.1.43). In 26 cross-sectional studies in patients with GOR symptoms, the OR for EO was 0.70 (95% CI 0.58-0.84) in H. pylori-positive vs -negative cases. Based on nine cross-sectional studies in subjects with GOR complications, no significant association was found between H. pylori infection and either endoscopically-diagnosed (OR 1.84, 95% CI 0.67-5.02) or histologically confirmed (OR 0.85, 95% CI 0.60-1.20) BO.

CONCLUSIONS

Helicobacter pylori infection appears to be associated with a decreased odds of GOR symptoms and EO. In contrast, H. pylori infection did not seem to affect the odds of BO in patients with GER complications.

Interaction Between Ethnicity and Helicobacter pylori Infection in the Occurrence of Reflux Disease

BACKGROUND AND AIMS

Few reports are available to reliably assess the ethnic distribution of Barrett metaplasia and reflux esophagitis. The present study served to analyze the joint influence of Helicobacter pylori infection and patient demographics on the diagnoses of Barrett metaplasia and reflux esophagitis.

METHODS

The Inform Diagnostics database is a national electronic repository of histopathologic records of patients distributed throughout the United States. In a case-control study of 52,096 cases with Barrett metaplasia, 189,235 cases with reflux esophagitis, and 152,322 controls without any signs or symptoms suggestive of gastroesophageal reflux disease, we assessed the influence of age, gender, ethnicity, and H. pylori status on occurrence of Barrett metaplasia or reflux esophagitis.

RESULTS

Barrett metaplasia was less common among East Asians (with odds ratio, 0.48; 95% confidence interval, 0.44-0.53) and Hispanics (0.60, 0.57-0.63) than other ethnic groups living in the United States. Reflux esophagitis was also less common among East Asians (0.86, 0.82-0.90), but more common among Hispanics (1.18, 1.14-1.21). Both types of esophageal disease were associated with a lower prevalence rates of gastric H. pylori infection than controls, with 0.48, 0.44-0.53 for Barrett metaplasia and 0.60, 0.57-0.63 for reflux esophagitis. The prevalence rates of gastric H. pylori and both esophageal diseases were greater in older than younger and male than female patients in all ethnic groups alike.

CONCLUSIONS

Gastric H. pylori infection, ethnicity, gender, and age all influence the occurrence of Barrett metaplasia, and reflux esophagitis.

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.

Clinical course of gastroesophageal reflux disease and impact of treatment in symptomatic young patients

In symptomatic young patients with gastroesophageal reflux symptoms, early identification of progressive gastroesophageal reflux disease (GERD) is critical to prevent long-term complications associated with hiatal hernia, increased esophageal acid and nonacid exposure, release of proinflammatory cytokines, and development of intestinal metaplasia, endoscopically visible Barrett's esophagus, and dysplasia leading to esophageal adenocarcinoma. Progression of GERD may occur in asymptomatic patients and in those under continuous acid-suppressive medication. The long-term side effects of proton-pump inhibitors, chemopreventive agents, and radiofrequency ablation are contentious. In patients with early-stage disease, when the lower esophageal sphincter function is still preserved and before endoscopically visible Barrett's esophagus develops, novel laparoscopic procedures, such as magnetic and electric sphincter augmentation, may have a greater role than conventional surgical therapy. A multidisciplinary approach to GERD by a dedicated team of gastroenterologists and surgeons might impact the patients' lifestyle, the therapeutic choices, and the course of the disease. Biological markers are needed to precisely assess the risk of disease progression and to tailor surveillance, ablation, and management.

IS THERE A RELATION BETWEEN HELYBACTER PYLORI AND INTESTINAL METAPLASIA IN SHORT COLUMN EPITELIZATION UP TO 10 MM IN THE DISTAL ESOPHAGUS?

Background:

The presence of intestinal metaplasia in the distal esophagus (Barrett’s esophagus) is an important precursor of adenocarcinoma. Knowledge of the risk factors and the process by which the Barrett develops is very important and Helicobacter pylori (HP) can contribute to this development.

Aim:

To analyze the impact of HP in the gastric mucosa with intestinal metaplasia in the distal esophagus in areas of columnar epithelialization smaller than 10 mm in length and epidemiological data on prevalence

Method:

A retrospective study in which were included 373 consecutive patients diagnosed with columnar epithelium in the distal esophagus was done. In all, HP was investigated by urease and histology, exclusion and inclusion factors were applied and patients were divided into two groups: the first grouping the ones without histological diagnosis of Barrett’s esophagus (235-63%) and the second with it (138-37%).

Results:

There was no significant difference between HP and non-HP patients in relation to the probability of having intestinal metaplasia (p=0.587). When related to the general group, there was an inverse association between the bacterium and the columnar epithelia in the distal esophagus. Age (p=0.031), gender (p=0.013) and HP (p=0.613) when related together to intestinal metaplasia showed no significant relation. In isolation, when related to age and gender, regardless of HP, results confirmed that patients in more advanced age and women present a higher incidence of intestinal metaplasia.

Conclusion:

There is an inverse relation between HP and the areas of columnar epithelization in the distal esophagus, regardless of the presence or absence of intestinal metaplasia. Age and gender, regardless of HP, showed higher prevalence in women and in older the number of cases with intestinal metaplasia in the distal esophagus.

Prevalence and risk factors for Barrett’s esophagus in Taiwan

BACKGROUND

Barrett’s esophagus (BE) is a pre-malignant condition associated with the development of esophageal adenocarcinoma. The prevalence of BE in the general populations of Asian countries ranges from 0.06% to 1%. However, with lifestyle changes in Asian countries and adoption of western customs, the prevalence of BE might have increased.

AIM

To determine the current prevalence of BE in Taiwan, and to investigate risk factors predicting the presence of BE.

METHODS

This retrospective study was conducted at the Health Evaluation Center of Kaohsiung Veterans General Hospital in Taiwan. Between January 2015 and December 2015, 3385 subjects undergoing routine esophagogastroduodenoscopy examinations as part of a health check-up at the Health Evaluation Center were included. Patient characteristics and endoscopic findings were carefully reviewed. Lesions with endoscopic findings consistent with BE awaiting histological evaluation were judged as endoscopically suspected esophageal metaplasia (ESEM). BE was defined based on extension of the columnar epithelium ≥ 1 cm above the gastroesophageal junction and was confirmed based on the presence of specialized intestinal metaplasia (IM) in the metaplastic esophageal epithelium. Clinical factors of subjects with BE and subjects without BE were compared, and the risk factors predicting BE were analyzed.

RESULTS

A total of 3385 subjects (mean age, 51.29 ± 11.42 years; 57.1% male) were included in the study, and 89 among them were confirmed to have IM and presence of goblet cells via biopsy examination. The majority of these individuals were classified as short segment BE (n = 85). The overall prevalence of BE was 2.6%. Multivariate analysis disclosed that old age [odds ratio (OR) = 1.033; 95% confidence interval (CI): 1.012-1.055; P = 0.002], male gender (OR = 2.106; 95%CI: 1.145-3.872; P = 0.017), ingestion of tea (OR = 1.695; 95%CI: 1.043-2.754; P = 0.033), and presence of hiatal hernia (OR = 3.037; 95%CI: 1.765-5.225; P < 0.001) were significant risk factors predicting BE. The independent risk factor for the presence of IM in ESEM lesions was old age alone (OR = 1.029; 95%CI: 1.006-1.053; P = 0.014).

CONCLUSION

Current prevalence of BE among the general population in Taiwan is 2.6%. Old age, male gender, ingestion of tea and hiatal hernia are significant risk factors for BE.

Interactions between Helicobacter pylori and gastroesophageal reflux disease

Interactions between Helicobacter Pylori (HP) and gastroesophageal reflux disease (GERD) are a complex issue. Several pathophysiological factors influence the development and the course of GERD, HP infection might be only one of these. Many studies emphasize the co-existence of these diseases. HP infection could contribute to GERD through both a protective and an aggressive role. Gastric acid secretion is a key factor in the pathophysiology of reflux esophagitis. Depending on the type of gastritis related to HP, acid secretion may either increase or decrease. Gastritis in corpus leads to hypoacidity, while antrum gastritis leads to hyperacidity. In cases of antral gastritis and duodenal ulcers which have hyperacidity, the expectation is an improvement in pre-existing reflux esophagitis after eradication of HP. In adults, HP infection is often associated with atrophic gastritis in the corpus. Atrophic gastritis may protect against GERD. Pangastritis which leads to gastric atrophy is commonly associated with CagA strains of HP and it causes more severe gastric inflammation. In case of HP-positive corpus gastritis in the stomach, pangastritis, and atrophic gastritis, reflux esophagitis occurs frequently after eradication of HP. Nonetheless, as a predisposing disease of gastric cancer, HP should be treated. In conclusion, as the determinative factors affecting GERD involving in HP, detailed data on the location of gastric inflammation and CagA positivity should be obtained by the studies at future.

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.

IVTH BRAZILIAN CONSENSUS CONFERENCE ON HELICOBACTER PYLORI INFECTION

ABSTRACT Significant progress has been obtained since the III Brazilian Consensus Conference on H. pylori infection held in 2012, in Bento Gonçalves, Brazil, and justify a fourth meeting to establish updated guidelines on the current management of H. pylori infection. Therefore, the Núcleo Brasileiro para Estudo do Helicobacter pylori e Microbiota (NBEHPM), association linked to Brazilian Federation of Gastroenterology (FBG) held its fourth meeting again in Bento Gonçalves, RS, Brazil, on August 25-27, 2017. Twenty-six delegates, including gastroenterologists, endoscopists, and pathologists from the five regions of Brazil as well as one international guest from the United States, participated in the meeting. The participants were invited based on their knowledge and contribution to the study of H. pylori infection. The meeting sought to review different aspects of treatment for infection; establish a correlation between infection, dyspepsia, intestinal microbiota changes, and other disorders with a special emphasis on gastric cancer; and reassess the epidemiological and diagnostic aspects of H. pylori infection. Participants were allocated into four groups as follows: 1) Epidemiology and Diagnosis, 2) Dyspepsia, intestinal microbiota and other afections, 3) Gastric Cancer, and, 4) Treatment. Before the consensus meeting, participants received a topic to be discussed and prepared a document containing a recent literature review and statements that should be discussed and eventually modified during the face-to-face meeting. All statements were evaluated in two rounds of voting. Initially, each participant discussed the document and statements with his group for possible modifications and voting. Subsequently, during a second voting in a plenary session in the presence of all participants, the statements were voted upon and eventually modified. The participants could vote using five alternatives: 1) strongly agree; 2) partially agree; 3) undecided; 4) disagree; and 5) strongly disagree. The adopted consensus index was that 80% of the participants responded that they strongly or partially agreed with each statement. The recommendations reported are intended to provide the most current and relevant evidences to management of H. pylori infection in adult population in Brazil.

Who Deserves Endoscopic Screening for Esophageal Neoplasia?

Despite the availability of safe and effective endoscopic treatment of Barrett's esophagus (BE)-related dysplasia and neoplasia, the incidence and mortality from esophageal adenocarcinoma (EAC) have continued to increase. This likely stems from the large population of patients that develop EAC outside of a BE screening and surveillance program. Identification of BE with screening followed by enrollment in an appropriate surveillance/risk stratification program could be a strategy to address both the incidence of and mortality from EAC. This article summarizes the rationale and challenges for BE screening, the risk factors for BE, and the currently described BE risk assessment tools.

Positive Helicobacter pylori status is associated with better overall survival for gastric cancer patients: evidence from case-cohort studies

Helicobacter pylori (H. pylori) infection increases the gastric cancer risk; however, the influences of H. pylori infection status on the outcomes for gastric cancer patients have not yet clearly defined. Herein, we systematically assessed the epidemiological studies regarding the associations between the H.pylori infection status at diagnosis and the prognosis for gastric cancer patients with the meta-analysis methods. Thirty-three eligibility studies with 8,199 participants that had determined the H.pylori infection status and the outcomes for gastric cancer patients were identified through searching the PubMed and MEDLINE databases updated to March 1^st, 2017. The random-effects model suggested that positive H. pylori infection was associated with better overall survival with the pooled hazard ratio (HR) was 0.79 [95% confidence interval (CI) = 0.66-0.93; Q = 134.86, df = 32, P-heterogeneity < 0.001; I² = 76.3%] compared to negative patients. The association was found to be more prominent in studies with higher quality, longer following-up time and more sensitive detection methods. An inverse but not statistically significant association between the H.pylori status and the disease-free survival of the patients (pooled HR = 0.84, 95% CI = 0.61-1.05;Q = 30.48, df = 11, P-heterogeneity = 0.001; I² = 63.9%) was found, while no significant association was noticed in any subgroup analyses. These results suggested that gastric cancer patients with positive H.pylori infection status at diagnosis have better overall survival compared to negative; however, more studies are warranted to confirm the results and elucidate the underlying mechanisms.

Adenocarcinoma of Barrett's esophagus in a dog

An endoscopic examination revealed a mass in the distal esophagus of a 9-year-old intact male bulldog. Histopathologically, the mass was composed of cuboidal to columnar neoplastic epithelial cells and extended from the squamous epithelium of the esophageal mucosa, indicating that the tumor was derived from Barrett’s esophagus. Moreover, highly atypical foci that exhibited a cribriform pattern and high mitotic indices were also observed. The epithelial cells on the surface of the lesion often produced mucus that was positive for Alcian blue and immunohistochemically positive for MUC5AC. The neoplastic epithelial cells were diffusely positive for cytokeratin 7 and p53, and occasionally positive for cytokeratin 20. Based on these findings, the tumor was diagnosed as an adenocarcinoma. This report describes the clinical and pathological features of a spontaneous case of adenocarcinoma of Barrett’s esophagus in a dog.

The Esophageal and Gastric Microbiome in Health and Disease

The esophagus and stomach are host to their own population of bacteria, which differs in health and disease. Helicobacter pylori uniquely colonizes only gastric mucosa, but an increasing number of bacteria is now isolated from the gastric juice and gastric mucosa, including Lactobacillus. The presence of H pylori alters populations of other gastric bacteria with a marked reduction in diversity. Alterations in intragastric acidity may be the cause or the consequence of changes in the microbial populations of the stomach. Esophageal inflammation is associated with an altered microbiota in gastroesophageal reflux disease, Barrett's esophagus, eosinophilic esophagitis, and cancer.

Risk factors for erosive and non-erosive gastroesophageal reflux disease and Barrett's esophagus in Nothern Sardinia

OBJECTIVE

Gastroesophageal reflux disease (GERD) and esophageal adenocarcinoma have been increasing. We studied the relationship of conventional risk factors and Helicobacter pylori infection in patients with erosive and non-erosive GERD and Barrett's esophagus.

MATERIALS AND METHODS

This was a retrospective study of dyspeptic patients undergoing upper endoscopy between 2002 and 2013. Following endoscopy, those with previously undiagnosed GERD were sub-grouped into non-erosive GERD (NERD), erosive GERD (eGERD), or Barrett's esophagus. H. pylori status was confirmed by 2 positive tests.

RESULTS

About 5156 patients were included, GERD was present in 65.6% including 1992 with NERD and 1392 with eGERD. About 1772 dyspeptic patients without symptoms of reflux and/or esophagitis served as controls. A hiatal hernia increased the risk of both eGERD and NERD. eGERD was more prevalent among the obese (OR =1.72, p < 0.001), men (OR =1.38, p < 0.001) and current smokers. Helicobacter pylori infection was significantly more common among those with NERD (OR =1.17 versus 1.01, p = 0.046). Logistic regression analysis for eGERD and NERD using age, gender, body mass index, H. pylori infection, hiatal hernia, and smoking showed that overweight and hiatal hernia were significant risk factors for eGERD, and female gender for NERD. Male gender, eGERD and age >50 years were the major risk factors for Barrett's esophagus.

CONCLUSIONS

The epidemiology of eGERD and NERD suggests differences in pathogenesis, and prevention and treatment strategies should be separately examined in men and women.

Approach to the patient with dysphagia

Dysphagia is a fascinating symptom. It is ostensibly simple when defined by trouble swallowing, yet its subtleties in deciphering and its variations in pathophysiology almost mandate a thorough knowledge of medicine itself. With patience and careful questioning, a multitude of various disorders may be suggested before an objective test is performed. Indeed, the ability to diligently and comprehensively explore the symptom of dysphagia is not only rewarding but also a real test for a physician who prides himself or herself on good history taking.

Reflux esophagitis triggered after Helicobacter pylori eradication: a noteworthy demerit of eradication therapy among the Japanese?

In the February 2013 Revision of Insured Medical Treatment, bacterial eradication for all Helicobacter pylori-positive individuals in Japan was covered under the insurance scheme. However, reflux esophagitis is believed to occur in approximately 10% of Japanese patients who undergo eradication therapy. Hence, the risk of reflux esophagitis among such cases should be carefully considered, particularly in the treatment for H. pylori-positive patients who are otherwise healthy. The eradication of H. pylori in cases of H. pylori-positive gastritis markedly suppresses gastric inflammation, and inhibits gastric mucosal atrophy and its progression to intestinal metaplasia. In a long-term follow-up study (10–20 years), eradication treatment was found to reduce the risk of subsequent gastric cancer. However, the fact that eradication-induced reflux esophagitis could increase the long-term risk of Barrett's esophagus and esophageal adenocarcinoma should also be considered in the Japanese population. Appropriate treatment with proton pump inhibitors should be taken into consideration for patients undergoing eradication therapy in clinical practice.

Epidemiology of Barrett's Esophagus and Esophageal Adenocarcinoma

Barrett's esophagus (BE) is the precursor to esophageal adenocarcinoma (EAC), a disease with increasing burden in the Western world, especially in white men. Risk factors for BE include obesity, tobacco smoking, and gastroesophageal reflux disease (GERD). EAC is the most common form of esophageal cancer in the United States. Risk factors include GERD, tobacco smoking, and obesity, whereas nonsteroidal antiinflammatory drugs and statins may be protective. Factors predicting progression from nondysplastic BE to EAC include dysplastic changes on esophageal histology and length of the involved BE segment. Biomarkers have shown promise, but none are approved for clinical use.

Barrett's oesophagus: frequency and prediction of dysplasia and cancer

The incidence of oesophageal adenocarcinoma is continuing to increase at an alarming rate in the Western world today. Barrett's oesophagus is a clearly recognized risk factor for the development of oesophageal adenocarcinoma, but the overwhelming majority of patients with Barrett's oesophagus will never develop oesophageal cancer. A number of endoscopic, histologic and epidemiologic risk factors identify Barrett's oesophagus patients at increased risk for progression to high-grade dysplasia and oesophageal adenocarcinoma. Endoscopic factors include segment length, mucosal abnormalities as seemingly trivial as oesophagitis and the 12 to 6 o'clock hemisphere of the oesophagus. Both intestinal metaplasia and low grade dysplasia, the latter only if confirmed by a pathologist with expertise in Barrett's oesophagus pathologic interpretation are the histologic risk factors for progression. Epidemiologic risk factors include ageing, male gender, obesity, and smoking. Factors that may protect against the development of adenocarcinoma include a diet rich in fruits and vegetables, and the use of proton pump inhibitors, aspirin/NSAIDs and statins.

Gastric acid secretion: changes during a century

The advances in knowledge of gastric physiology within the past century have been the most exciting and important in this area of interest for many decades. The aim of this presentation consists of a comprehensive review of the extensive recent literature on this topic in order to highlight milestones in the field of gastric physiology, in particular in gastric acid secretion, gastric pathophysiology, acid-related diseases and use of acid regulatory drugs. Moreover, in the 21st century there have been many epidemiologic changes as well as a decrease of Helicobacter pylori infection and gastric cancer together with an increase of gastroesophageal reflux disease and the related increase of pomp proton inhibitor wide use.

The impact of proton pump inhibitors on the human gastrointestinal microbiome

Potent gastric acid suppression using proton pump inhibitors (PPIs) is common in clinical practice but may have important effects on human health that are mediated through changes in the gastrointestinal microbiome. In the esophagus, PPIs change the normal bacterial milieu to decrease distal esophageal exposure to inflammatory gram-negative bacteria. In the stomach, PPIs alter the abundance and location of gastric Helicobacter pylori and other bacteria. In the small bowel, PPIs cause polymicrobial small bowel bacterial overgrowth and have been associated with the diagnosis of celiac disease. In the colon, PPIs associate with incident but not recurrent Clostridium difficile infection.

Helicobacter pylori: perspectives and time trends

The discovery of Helicobacter pylori three decades ago is a modern medical success story. It markedly changed our understanding of the pathophysiology of gastroduodenal diseases and led to an improvement in the treatment of diseases related to H. pylori infection. Many of these diseases (such as ulcer disease and mucosal associated lymphoid tissue lymphoma) have become curable, and others (gastric cancer) might be preventable with the application of H. pylori eradication therapy. Since its discovery, H. pylori has also been identified as a trigger for some extragastric diseases. Promising results in this exciting field might have a clinical effect in the near future. This Timeline gives an overview of the success of clinical research on H. pylori to date and highlights some future trends in this area.

Barrett’s oesophagus: Evidence from the current meta-analyses

Guidelines have been published regarding the management of Barrett’s oesophagus (columnar-lined oesophagus). These have examined the role of surveillance in an effort to detect dysplasia and early cancer. The guidelines have provided criteria for enrolment into surveillance and some risk stratification with regard to surveillance interval. The research basis for the decisions reached with regard to cancer risk is weak and this manuscript has examined the available data published from meta-analyses up to 25^th April 2013 (much of which has been published since the guidelines and their most recent updates have been written). There were 9 meta-analyses comparing patients with Barrett’s oesophagus to control populations. These have demonstrated that Barrett’s oesophagus is more common in males than females, in subjects who have ever smoked, in subjects with obesity, in subjects with prolonged symptoms of gastro-oesophageal reflux disease, in subjects who do not have infection with Helicobacter pylori and in subjects with hiatus hernia. These findings should inform public health measures in reducing the risk of Barrett’s oesophagus and subsequent surveillance burden and cancer risk. There were 8 meta-analyses comparing different groups of patients with Barrett’s oesophagus with regard to cancer risk. These have demonstrated that there was no statistically significant benefit of antireflux surgery over medical therapy, that endoscopic ablative therapy was effective in reducing cancer risk that there was similar cancer risk in patients with Barrett’s oesophagus independent of geographic origin, that the adenocarcinoma incidence in males is twice the rate in females, that the cancer risk in long segment disease showed a trend to be higher than in short segment disease, that there was a trend for higher cancer risk in low-grade dysplasia over non-dysplastic Barrett’s oesophagus, that there is a lower risk in patients with Helicobacter pylori infection and that there is a significant protective effect of aspirin and statins. There were no meta-analyses examining the role of intestinal metaplasia. These results demonstrate that guidance regarding surveillance based on the presence of intestinal metaplasia, segment length and the presence of low-grade dysplasia has a weak basis, and further consideration should be given to gender and helicobacter status, ablation of the metaplastic segment as well as the chemoprotective role of aspirin and statins.

Helicobacter pylori and gastroesophageal reflux disease

PURPOSE OF REVIEW

The purpose of the review is to discuss key studies conducted on the intriguing relationship between Helicobacter pylori and gastroesophageal reflux disease.

RECENT FINDINGS

Epidemiological studies have repeatedly described a negative association between H. pylori infection and erosive esophagitis, Barrett's esophagus, and esophageal adenocarcinoma, but not between H. pylori and gastroesophageal reflux disease symptoms. Especially, infection with CagA-positive strains appears to protect the distal esophagus by causing fundic gland atrophy and impaired gastric acid secretion. Although earlier reports suggested the development of erosive esophagitis after H. pylori eradication, more recent studies discuss that H. pylori eradication usually does not have an important clinical impact on gastroesophageal reflux disease.

SUMMARY

Gastric atrophy is the most widely accepted mechanism by which the distal esophagus is protected from abnormal acid exposure in patients with H. pylori infection. The clinical impact of H. pylori infection on the prevalence of erosive esophagitis and Barrett's esophagus remains a matter of debate. In areas with a high prevalence of H. pylori-induced atrophic gastritis, the protection that this infection may afford against gastroesophageal reflux disease is not comparable to the risk that H. pylori poses for the development of gastric cancer.

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.

Association between Helicobacter pylori and Barrett's esophagus: a case-control study

OBJECTIVES

The estimated association between Helicobacter pylori and Barrett's esophagus (BE) has been heterogenous across previous studies. In this study, we aimed to examine the association between H. pylori and BE and to identify factors that may explain or modify this association.

METHODS

We conducted a case-control study in which we used screening colonoscopy controls recruited from primary care clinics as our primary control group in order to minimize selection bias. All participants underwent an esophagogastroduodenoscopy with gastric mapping biopsies. We used logistic regression to obtain odds ratios (ORs) and 95% confidence intervals (CIs) to estimate the association between H. pylori and BE while controlling for confounders.

RESULTS

We identified 218 cases and 439 controls. The overall OR for the association between H. pylori and BE after controlling for age and white race was 0.55 (95% CI: 0.35-0.84). We observed an even stronger inverse association (OR: 0.28; 95% CI: 0.15, 0.50) among participants with corpus atrophy or antisecretory drug use ≥ 1 time per week (factors thought to lower gastric acidity), and no inverse association in patients without these factors (OR: 1.32; 95% CI: 0.66, 2.63).

CONCLUSIONS

The association between H. pylori and a decreased risk for BE appears to occur in patients with factors that would likely lower gastric acidity (corpus atrophy or taking antisecretory drugs at least once a week).

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.

Review article: historic changes of Helicobacter pylori-associated diseases

BACKGROUND

The long-term time trends of multiple gastrointestinal diseases are characterised by a striking rise and fall. These temporal changes provide important clues about disease aetiology.

AIM

To highlight the importance of Helicobacter pylori infection in shaping the temporal trends of many common gastrointestinal diseases.

METHODS

Literature review of the time trends associated with common digestive diseases.

RESULTS

The general trends of gastric ulcer, duodenal ulcer, gastric cancer, colon cancer, rectum cancer have all been shaped by a similar underlying birth-cohort phenomenon. Mortality associated with these diagnoses increased in all generations born during the nineteenth century. It peaked among generations born shortly before the turn of the century and then decreased in all subsequent generations born throughout the twentieth century. These patterns can be observed in the incidence, hospitalisation and mortality data from many different countries. They reflect similar rising and falling trends of H. pylori infection in the general population. Diseases that are inversely associated with H. pylori, such as reflux disease, erosive oesophagitis, Barrett's oesophagus, and oesophageal adenocarcinoma, have seen a striking rise during the recent decline of H. pylori infection.

CONCLUSION

The temporal variations of H. pylori infection have affected the occurrence of gastroenterology's most common disorders.

Advances in gastric cancer prevention

Gastric cancer is a multifactorial neoplastic pathology numbering among its causes both environmental and genetic predisposing factors. It is mainly diffused in South America and South-East Asia, where it shows the highest morbility percentages and it is relatively scarcely diffused in Western countries and North America. Although molecular mechanisms leading to gastric cancer development are only partially known, three main causes are well characterized: Helicobacter pylori (H. pylori) infection, diet rich in salted and/or smoked food and red meat, and epithelial cadherin (E-cadherin) mutations. Unhealthy diet and H. pylori infection are able to induce in stomach cancer cells genotypic and phenotypic transformation, but their effects may be crossed by a diet rich in vegetables and fresh fruits. Various authors have recently focused their attention on the importance of a well balanced diet, suggesting a necessary dietary education starting from childhood. A constant surveillance will be necessary in people carrying E-cadherin mutations, since they are highly prone in developing gastric cancer, also within the inner stomach layers. Above all in the United States, several carriers decided to undergo a gastrectomy, preferring changing their lifestyle than living with the awareness of the development of a possible gastric cancer. This kind of choice is strictly personal, hence a decision cannot be suggested within the clinical management. Here we summarize the key points of gastric cancer prevention analyzing possible strategies referred to the different predisposing factors. We will discuss about the effects of diet, H. pylori infection and E-cadherin mutations and how each of them can be handled.

The association between Barrett's esophagus and Helicobacter pylori infection: a meta-analysis

OBJECTIVE

The effect of Helicobacter pylori on Barrett's esophagus is poorly understood. We conducted a meta-analysis to summarize the existing literature examining the effect that H. pylori has on Barrett's esophagus.

DESIGN

 We performed a comprehensive search to identify studies pertaining to the association between H. pylori and Barrett's esophagus. We conducted meta-regression analyses to identify sources of variation in the effect of H. pylori on Barrett's esophagus.

RESULTS

 Our analysis included a total of 49 studies that examined the effect of H. pylori on Barrett's esophagus and seven studies that examined the effect of cag A positivity on Barrett's esophagus. Overall, H. pylori, and even more so cag A, tended to be protective for Barrett's esophagus in most studies; however, there was obvious heterogeneity across studies. The effect of H. pylori on Barrett's esophagus varied by geographic location and in the presence of selection and information biases. Only four studies were found without obvious selection and information bias, and these showed a protective effect of H. pylori on Barrett's esophagus (Relative risk = 0.46 [95% CI: 0.35, 0.60]).

CONCLUSIONS

 Estimates for the effect of H. pylori on Barrett's esophagus were heterogeneous across studies. We identified selection and information bias as potential sources of this heterogeneity. Few studies without obvious selection and information bias have been conducted to examine the effect of H. pylori on Barrett's esophagus, but in these, H. pylori infection is associated with a reduced risk of Barrett's esophagus.

Barrett's esophagus and esophageal cancer: an overview

Although esophageal cancer (EC) is the eighth most common cancer in several European countries, it is one of deadliest worldwide. The most frequent predisposing factor implicated in its development is Barrett's esophagus (BE), an acquired metaplastic transformation of the esophageal lining cells from normal squamous epithelium into specialised or intestinal-like columnar epithelium. The major risk factor for BE is gastroesophageal reflux disease. Although BE is in itself a benign and often asymptomatic disorder, its clinical importance stems from the recognition that it represents the main precursor lesion for the development of esophageal adenocarcinoma (AC), a tumor that is rapidly increasing especially in developed countries and is associated with a low survival rate. This paper provides an overview of the epidemiology and natural history of BE as well as of the possible pathogenetic mechanisms underlying the development of BE and its progressive transition to AC. New diagnostic tests are described, recommendations for screening and surveillance are provided and surgical and ablative procedures to treat dysplastic lesions and early neoplasia are discussed. Claimed chemopreventive agents and biomarkers that in the near future may help identify people with a higher risk of EC are also considered.

Helicobacter pylori: Eradication or Preservation

Helicobacter pylori infects about 50% of the world's population and inevitably results in the development of gastritis. Of those infected, about 10% develop peptic ulcer disease and roughly 1% develop gastric cancer. Conversely, some take the view that H. pylori infection provides some protection against gastro-esophageal reflux disease and possibly asthma. This review aims to explore the case for and against eradication of the bacterium using a "test and treat" approach amongst the general population.

IRAK-M modulates expression of IL-10 and cell surface markers CD80 and MHC II after bacterial re-stimulation of tolerized dendritic cells

BACKGROUND

As essential components of the innate immune system, dendritic cells (DCs) can interact directly with pathogens as well as participate in the adaptive immune response. In cells closely related to DCs such as macrophages and monocytes, prior exposure to minute amounts of endotoxin can lead to a refractory period where subsequent exposure to higher doses fails to induce an inflammatory response; little research has investigated this effect on DCs. This study tested if murine bone marrow-derived dendritic cells (BM-DCs) respond to endotoxin- and bacterial sonicate-induced tolerance by decreased inflammatory and increased anti-inflammatory response, and the role of IRAK-M, an intracellular negative regulator of TLR signaling, in this tolerance.

RESULTS

Tolerized BM-DCs exhibited a significant drop in TNF-α and IL-12p70 production and increased IL-10 expression compared to untolerized cells. BM-DCs also showed the ability to develop heterotolerance, in which the LPS exposure alone was able to induce tolerance to Helicobacter pylori sonicate and TLR2 agonist Pam3Cys. Furthermore, the expression of IRAK-M was increased after restimulation of tolerized BM-DCs as determined qPCR and Western blot. IRAK-M exhibited a suppressive effect on surface expression of major histocompatibilty complex class II (MHC II) and CD80 in LPS-tolerized BM-DCs. IL-10 expression in bacterial sonicate-tolerized IRAK-M-/- BM-DCs was altered as compared to wild type BM-DCs, with tolerance-induced expression of IL-10 mitigated in tolerized IRAK-M-/- BM-DCs.

CONCLUSION

Along with endotoxin, bacterial sonicate is able to induce refractory tolerance in BM-DCs, and IRAK-M plays a role in modulating cell surface expression of MHC class II and CD80 and release of IL-10 during this tolerance.

Low prevalence of Helicobacter pylori infection among patients with inflammatory bowel disease

BACKGROUND

There is some preliminary evidence to suggest that patients with inflammatory bowel disease (IBD) are less frequently infected with Helicobacter pylori than the general population.

AIM

To examine whether the prevalence of Helicobacter pylori (H. pylori) is lower among IBD patients compared with non-IBD individuals based on results from surgical pathology.

METHODS

From a database of surgical pathology reports, we recruited a sample of unique patients who underwent a same-day bidirectional gastrointestinal endoscopy with biopsies. Of the total 65,515 patients, 1061 served as cases with IBD and 64,451 as controls without IBD. The histological presence of H. pylori was correlated with the patients' demographic characteristics and histological presence of any oesophageal disease, Crohn's disease (CD), ulcerative colitis (UC) and indeterminate colitis (IND). Results were expressed as odds ratios (OR), using multivariate logistic regression to adjust for the cofounding influence of comorbidities and demographic characteristics.

RESULTS

The presence of H. pylori was inversely associated with IBD, the adjusted OR and their 95% confidence intervals being 0.48 (0.27-0.79) for CD, 0.59 (0.39-0.84) for UC and 0.43 (0.15-0.95) for IND. In contradistinction, H. pylori-negative gastritis was positively associated with IBD, the adjusted OR being 11.06 (7.98-15.02) for CD, 2.25 (1.31-3.60) for UC and 6.91 (3.50-12.30) for IND.

CONCLUSIONS

Our study confirms an inverse association between H. pylori and IBD and a positive association between the H. pylori-negative gastritis and IBD. These relationships may open new avenues to study the pathogenesis of IBD.

Barrett's esophagus: prevalence-incidence and etiology-origins

Although the prevalence of Barrett's esophagus (BE) is rising no data exist for racial minorities on prevalence in the general population. Minorities have a lower prevalence than Caucasians, and yet age, smoking, abdominal obesity, and Helicobacter pylori are all risk factors. Metabolic changes induced by adipocytokines and the apparently strong association between obesity, central adiposity, and BE may lead to reconsideration of some aspects of the natural history of BE. There is lack of experimental evidence on acid sensitivity and BE, which is hyposensitive compared to esophageal reflux disease. Reactive nitrogen and oxygen species lead to impaired expression of tumor suppressor genes, which can lead to cancer development; thus, antioxidants may be protective. Gastroesophageal reflux disease may be considered an immune-mediated disease starting at the submucosal layer; the cytokine profile of the mucosal immune response may explain the different outcome of gastroesophageal reflux.

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

Infection with Helicobacter pylori is associated with significantly reduced risks of oesophageal adenocarcinoma; however, few studies have examined the association between H. pylori and Barrett's oesophagus (BO), the precursor lesion. We explored the relationship between H. pylori infection and BO and sought to identify potential modifiers. We compared the prevalence of positive H. pylori serology among 217 adults with simple BO (without dysplasia), 95 with dysplastic BO and 398 population controls sourced from the metropolitan Brisbane area. We determined H. pylori serostatus using enzyme-linked immunosorbent assay. To estimate relative risks, we calculated odds ratios (OR) and 95% confidence intervals (CI) using multivariable logistic regression in the entire sample and stratified by factors known to cause BO. The prevalence of H. pylori seropositivity was 12%, 3%, and 18%, respectively, among patients with simple BO, dysplastic BO and population controls. BO patients were significantly less likely to have antibodies for H. pylori (Simple BO: OR = 0.51, 95% CI: 0.30-0.86; Dysplastic BO: OR = 0.10, 95% CI: 0.03-0.33) than population controls. For simple BO, the association was diminished after adjustment for frequency of gastro-oesophageal reflux (GOR) symptoms. Adjustment for frequency of GOR symptoms did not substantially alter the observed effect for dysplastic BO. Although there was some variation in the magnitude of risk estimates across strata of age, sex, GOR symptoms and use of proton pump inhibitors or H2-receptor antagonists, the differences were uniformly nonsignificant. Helicobacter pylori infection is inversely associated with BO, and our findings suggest that decreased acid load is not the only mechanism underlying the H. pylori protective effect.

Barrett's esophagus

Barrett's esophagus is an acquired metaplastic abnormality in which the normal stratified squamous epithelium lining of the esophagus is replaced by an intestinal-like columnar epithelium. While in itself a benign and asymptomatic disorder, the clinical importance of this relatively common condition relates to its role as a precursor lesion to esophageal adenocarcinoma, the incidence of which has dramatically increased in Western populations in recent years. Although known to arise as a consequence of chronic gastroesophageal reflux, the cellular and molecular mechanisms underlying development Barrett's esophagus and its progression to cancer remain unclear.

Role of bacteria in oncogenesis

Although scientific knowledge in viral oncology has exploded in the 20th century, the role of bacteria as mediators of oncogenesis has been less well elucidated. Understanding bacterial carcinogenesis has become increasingly important as a possible means of cancer prevention. This review summarizes clinical, epidemiological, and experimental evidence as well as possible mechanisms of bacterial induction of or protection from malignancy.

A national study of Helicobactor pylori infection in gastric biopsy specimens

BACKGROUND & AIMS

We investigated whether infection with Helicobacter pylori and signs of chronic active gastritis and intestinal metaplasia in gastric biopsy samples were inversely associated with Barrett's metaplasia.

METHODS

We studied gastric biopsy samples from 78,985 unique patients. Histologic findings were correlated with sociodemographic patient characteristics using multivariate logistic regression to calculate odds ratios and 95% confidence intervals.

RESULTS

H pylori infection, chronic active gastritis, and intestinal metaplasia had similar epidemiologic patterns. The presence of each, based on histology analyses, was significantly associated with that of the others. They were also characterized by similar geographic distributions within the United States. All 3 disorders were more common among men and among Medicaid patients (compared with those with other insurance) and were inversely associated with Barrett's metaplasia (less frequent in patients with Barrett's metaplasia).

CONCLUSIONS

H pylori infection and associated disorders, such as chronic active gastritis and intestinal metaplasia, are inversely associated with Barrett's metaplasia.

Association of Helicobacter pylori infection with reduced risk for esophageal cancer is independent of environmental and genetic modifiers

BACKGROUND & AIMS

Infection with Helicobacter pylori is associated with reduced risk of esophageal adenocarcinoma (EAC), but it is not clear whether this reduction is modified by genotype, other host characteristics, or environmental factors. Furthermore, little is known about the association between H pylori and adenocarcinomas of the esophagogastric junction (EGJAC) or squamous cell carcinomas (ESCC). We sought to measure the association between H pylori infection and esophageal cancer and identify potential modifiers.

METHODS

In an Australian, population-based, case-control study, we compared the prevalence of H pylori seropositivity and single nucleotide polymorphisms in interleukin (IL)-1B (-31, -511) and tumor necrosis factor (TNF)-alpha (-308, -238) among 260 EAC, 298 EGJAC, and 208 ESCC patients and 1346 controls. To estimate relative risks, we calculated odds ratios (OR) and 95% confidence intervals (CI) using multivariable logistic regression in the entire sample and within strata of phenotypic and genotypic risk factors.

RESULTS

H pylori infection was associated with significantly reduced risks of EAC (OR, 0.45; 95% CI: 0.30-0.67) and EGJAC (OR, 0.41; 95% CI: 0.27-0.60) but not ESCC (OR, 1.04; 95% CI: 0.71-1.50). For each cancer subtype, risks were of similar magnitude across strata of reflux frequency and smoking status. We found no evidence that polymorphisms in IL-1B or TNF-alpha modified the association between H pylori and EAC or EGJAC.

CONCLUSIONS

H pylori infection is inversely associated with risks of EAC and EGJAC (but not ESCC); the reduction in risk is similar across subgroups of potential modifiers.