The prevalence of Helicobacter pylori infection and the pattern of gastritis in Barrett's esophagus

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.

Effect of Helicobacter pylori infection on esophageal epithelial cells in vitro

AIM: To investigate the effect of Helicobacter pylori (H. pylori) exposure on esophageal cell line OE33 in vitro.

METHODS: Human esophageal adenocarcinoma cell line OE33 was cultured and treated with 200 mmol/L acidified deoxycholic acid (pH 6.0) or infected with H. pylori 26695. After treatment or infection, cell viability was tested by CCK-8 assay; cell apoptosis was determined by flow cytometric analysis with Annexin V-FITC/7-AAD; the mRNA expression of CDX2 and MUC2 was assessed by real time-PCR; nuclear factor-kB (NF-kB)-associated proteins were examined by Western blot; and the DNA binding activity of NF-kB was evaluated by electrophoretic mobility shift assay (EMSA).

RESULTS: The viability of OE33 cells was reduced significantly after treatment with acidified deoxycholic acid or infection with H. pylori compared with negative controls (both P < 0.01). Treatment with acidified deoxycholic acid or infection with H. pylori induced apoptosis and increased the mRNA expression of CDX2 and MUC2 (all P < 0.01). Both H. pylori infection and treatment with acidified deoxycholic acid enhanced the DNA binding activity of NF-kB and the protein expression of phosphorylated IkBa and P65 in esophageal epithelial cells.

CONCLUSION: H. pylori infection reduces cell viability, induces apoptosis, and increases the expression of CDX2 and MUC2 and the activation of NF-kB in esophageal epithelial cells.

Are carcinomas of the cardia oesophageal or gastric adenocarcinomas?

There is a clear relationship between Barrett's oesophagus and oesophageal adenocarcinoma, and between Helicobacter pylori and gastric cancer, but the histogenesis of cardiac adenocarcinomas is unknown. Some clues as to possible disease associations may be provided by the pattern of gastritis. In our study, we analysed gastritis associated with oesophageal, cardiac and gastric adenocarcinomas according to the Sydney classification. Chronic gastritis was more common in gastric (88%) than in cardiac (56%) and oesophageal adenocarcinomas (38%). H. pylori was significantly more prevalent in gastric (73%) than in cardiac (34%) or oesophageal (21%) adenocarcinomas. Our results show that factors other than H. pylori must be involved in the histogenesis of cardiac adenocarcinomas. As the pattern of gastritis and the clinical features of cardiac adenocarcinomas are more comparable to oesophageal carcinomas than gastric carcinomas, we speculate that most of these tumours share similar aetiological factors with oesophageal carcinomas.

Barrett esophagus

A number of publications have provided valuable insight into and data on the epidemiology, pathogenesis, diagnosis, risk factor evaluation, and treatment of patients with Barrett esophagus. Although the incidence of esophageal adenocarcinoma has rapidly increased over the past two decades, it is not clear whether there has been a parallel increase in the frequency of Barrett esophagus. The issue of surveillance endoscopy in patients with Barrett esophagus remains controversial; prospective data are still lacking. Bile reflux plays an important role in the pathogenesis of Barrett esophagus; however, this usually occurs in the presence of acid. Newer technology and techniques, including chromoendoscopy, magnification endoscopy, optical coherence tomography, and spectroscopy, have opened the field by providing a more accurate and "nonbiopsy" diagnosis of intestinal metaplasia and dysplasia. The field of biomarkers remains continues to expand and is providing insight into risk stratification of patients with Barrett esophagus. The exact role of acid suppression in patients with this premalignant disease remains controversial, and endoscopic therapies appear promising.