Helicobacter pylori infection and the risk of gastric malignancy

Investigating Associations between HLA-DR Genotype, H. pylori Infection, and Anti-CagA IgA Seropositivity in a Turkish Gastritis Cohort

Helicobacter pylori (H. pylori) is associated with gastric inflammation and mucosal antibodies against its cytotoxin-associated gene A (CagA) are protective. Vaccine-elicited immunity against H. pylori requires MHC class II expression, indicating that CD4+ T cells are protective. We hypothesized that the HLA-DR genotypes in human populations include protective alleles that more effectively bind immunogenic CagA peptide fragments and susceptible alleles with an impaired capacity to present CagA peptides. We recruited patients (n = 170) admitted for gastroendoscopy procedures and performed high-resolution HLA-DRB1 typing. Serum anti-CagA IgA levels were analyzed by ELISA (23.2% positive) and H. pylori classified as positive or negative in gastric mucosal tissue slides (72.9% positive). Pearson Chi-square analysis revealed that H. pylori infection was significantly increased in DRB1*11:04-positive individuals (p = 0.027). Anti-CagA IgA was significantly decreased in DRB1*11:04 positive individuals (p = 0.041). In contrast, anti-CagA IgA was significantly increased in DRB1*03:01 positive individuals (p = 0.030). For these HLA-DRB1 alleles of interest, we utilized two in silico prediction methods to compare their capacity to present CagA peptides. Both methods predicted increased numbers of peptides for DRB1*03:01 than DRB1*11:04. In addition, both alleles preferred distinctively different CagA 15mer peptide sequences for high affinity binding. These observations suggest that DRB1*11:04 is a susceptible genotype with impaired CagA immunity, whereas DRB1*03:01 is a protective genotype that promotes enhanced CagA immunity.

Prevalence of Gastric Precursor Lesions in Countries With Differential Gastric Cancer Burden: A Systematic Review and Meta-analysis

BACKGROUND & AIMS

The prevalence of precursor lesions for gastric cancer (GC) and the differential burden between countries of varying GC risk is not well-understood. We conducted a systematic review and meta-analysis to estimate the global prevalence of precursor lesions.

METHODS

We estimated the prevalence of atrophic gastritis (AG), gastric intestinal metaplasia (IM), and dysplasia in regions with low, medium, and high GC incidence. Because IM is an advanced manifestation of AG, we assessed the prevalence of less advanced precursors, regardless of the presence of more advanced lesions. Prevalence was sub-stratified by Helicobacter pylori infection, symptomatology, and period (<2000, 2000-2010, and >2010).

RESULTS

Among the 582 articles that underwent full-text review, 166 studies met inclusion criteria. The global prevalence estimates of AG, IM, and dysplasia were 25.4%, 16.2%, and 2.0%, respectively, on the basis of 126 studies that reported the prevalence of less advanced precursors, regardless of the presence of more advanced lesions. The prevalence of all precursor lesions was higher in high and medium compared with low GC incidence countries (P < .01). Prevalence of AG and IM was significantly higher among H pylori-infected individuals (P < .01) but not statistically different between symptomatic and asymptomatic individuals (P > .17). All precursors demonstrated a secular decrease in prevalence over time.

CONCLUSIONS

Gastric precursor lesions have differences in prevalence in regions with differential GC incidence and are associated with H pylori infection. Because of the substantial prevalence of precursor lesions in both symptomatic and asymptomatic individuals, symptomatic evaluation may not be sufficient to identify individuals at risk. These estimates provide important insights for tailoring GC prevention strategies.

Lacticaseibacillus casei T1 attenuates Helicobacter pylori-induced inflammation and gut microbiota disorders in mice

Probiotics are defined as live microbial food elements that are beneficial to human health. Lacticaseibacillus casei T1 was considered to have potential as a bioactive ingredient in functional foods, which was isolated from kurut. Previous research by our group proved that L. casei T1 could prevent inflammatory responses caused by Helicobacter pylori. This study aimed to investigate whether treatment with L. casei T1 resulted in a suppressive effect on H. pylori-induced oxidative stress and inflammatory responses. The results showed that treatment with L. casei T1 could relieve H. pylori-induced overexpression of inflammatory cytokines in GES-1 cells. Experiments in animals suggested that taking long-term L. casei T1 could reduce oxidative stress and inflammatory cytokines and improve H. pylori-induced gastric mucosal damage. Furthermore, taking L. casei T1 could increase the relative abundance of beneficial intestinal bacterium (Lachnospiraceae and Odoribacter) of H. pylori-infected mice and help in maintaining the balance of intestinal microflora.Collectively, L. casei T1 had certain degrees of therapeutic effect against H. pylori. In the future, it combined with antibiotics for H. pylori eradication deserves further study.

Declining trends of prevalence of Helicobacter pylori infection and incidence of gastric cancer in Taiwan: An updated cross-sectional survey and meta-analysis

BACKGROUND

We aimed to assess the latest prevalence and secular trend of Helicobacter pylori infection and its association with the incidence and mortality of gastric cancer in Taiwan.

MATERIALS AND METHODS

Adults naive to H. pylori eradication received ¹³ C-urea breath test (¹³ C-UBT), H. pylori stool antigen test, and serology test during 2019-2020 in this prospective screening program. Children and adolescent aged between 7 and 19 years received ¹³ C-UBT for H. pylori screening. We also conducted a systematic review and meta-analysis to assess the secular trend of prevalence of H. pylori from 1990 to 2020 in Taiwan. The secular trends of age-standardized incidence and mortality of gastric cancer were obtained from the Taiwan Cancer Registry.

RESULTS

A total of 1494 participants were enrolled, including 294 children or adolescents and 1200 adults. The overall prevalence of active H. pylori infection by ¹³ C-UBT was 26.6% (397/1494), which was 30.8% in adults and 9.5% in adolescents/children. The age-standardized prevalence of active H. pylori infection was 32.3% in adults after adjustment of the population structure in Taiwan. Of the 29 studies including 38,597 subjects eligible for the meta-analysis, the pooled prevalence of H. pylori infection decreased from 63.8% (95% CI: 55.9%-71%) in 1990-2000 to 28.2% (95% CI:21.8%-35.6%) in 2016-2020. The age-standardized incidence and mortality of gastric cancer have also declined from 15.2 to 10.75 per 100,000, respectively, in 1999 to 9.29 and 5.4 per 100,000, respectively, in 2019.

CONCLUSIONS

The prevalence of H. pylori infection has declined in Taiwan, which correlates with the declining trends of age-standardized incidence and mortality of gastric cancer in Taiwan.

The efficacy of culture-guided versus empirical therapy with high-dose proton pump inhibitor as third-line treatment of Helicobacter pylori infection: A real-world clinical experience

BACKGROUND AND AIM

Most consensuses recommend culture-guided therapy as third-line Helicobacter pylori treatment. This study aimed to investigate the efficacies of culture-guided therapy and empirical therapy with high-dose proton pump inhibitor (PPI) in the H. pylori third-line treatment.

METHODS

Between August 2012 and October 2021, H. pylori-infected patients with at least two failed eradication attempts received anti-H. pylori therapy according to the results of antimicrobial sensitivity tests plus high-dose rabeprazole and/or bismuth. They were categorized into three groups: patients who had positive results of culture with equal to or more than three susceptible antibiotics were treated by culture-guided non-bismuth quadruple therapy, patients who had positive results of culture with one or two susceptible antibiotics were treated by culture-guided bismuth-containing therapy, and patients who had a negative result of culture were treated by an empirical therapy with high-dose rabeprazole plus amoxicillin, tetracycline and levofloxacin. A post-treatment assessment was conducted at week 8.

RESULTS

We recruited 126 patients. The eradication rates of culture-guided non-bismuth quadruple therapy (n = 50), culture-guided bismuth-containing therapy (n = 46) and empirical therapy (n = 30) were 84.0%, 87.0%, and 66.7% (95% confidence interval: 73.8-94.2%, 77.3-96.7%, and 49.8-83.6%), respectively. Overall, culture-guided therapy achieved a higher eradication rate than empirical therapy (85.4% vs 66.7%; 95% confidence interval, 0.4% to 37.0%, P = 0.022).

CONCLUSIONS

Culture-guided therapy with high-dose PPI achieves a higher eradication rate than empirical therapy with high-dose PPI in the third-line treatment of H. pylori infection. The eradication rate of rescue therapy with bismuth plus two susceptible antibiotics is not inferior to that with three susceptible antibiotics.

Involvement of Helicobacter pylori in Preoperative Gastric Findings on a Bariatric Population

The prevalence of Helicobacter pylori (Hp) in bariatric patients is common and related to gastric pathology. With preoperative upper gastrointestinal endoscopy (UGE), these pathologies and the presence of Hp are diagnosed. The histopathological study of the UGE biopsies is classified based on the Sydney System, a scoring system that stages chronic gastritis (CG) and precancerous gastric lesions. The objective is to assess the histological findings of gastric biopsies during routine UGE and to determine the involvement of Hp in gastric disorders in patients undergoing bariatric surgery. A multicenter retrospective review of prospectively collected databases was performed. The presence of CG, gastric atrophy (GA), and gastric intestinal metaplasia (GIM) in the study of the biopsies was assessed and correlated with Hp infection. The incidence of Hp among our bariatric population was 36.1%, and it increases with age. The percentage of patients with severe Hp infection is higher in patients with GA or GIM. The Hp eradication rate is also reduced when GA and GIM are present. A histological examination of all the biopsies did not show features of malignancy in any of the cases. Hp is not the only factor involved in the development of gastric pathology in bariatric patients.

Multiple surface interaction mechanisms direct the anchoring, co-aggregation and formation of dual-species biofilm between Candida albicans and Helicobacter pylori

Introduction

Polymicrobial biofilms have a significant impact on pathogenesis of infectious microorganisms. Many human diseases are affected by colonization of multi-species communities affecting negatively the treatments and increase the risks for the health. In particular, in the epithelium of the stomach co-existence between C. albicans and H. pylori has been described, which has been associated to a synergistic effect on ulcer pathogenesis.

Objective

The objective of this work was to advance in the understanding of surface interaction between H. pylori and C. albicans for the formation of polymicrobial biofilms.

Methods

Studies of microbial surfaces both bacterium, yeast and co-cultures of them were carried out by infrared spectroscopy, deconvolution analysis, transmission and scanning electron microscopies, and optic microscopy. Additional methods were used to contrast the results as dynamic light scattering, contact angle, agarose gel electrophoresis and gene amplification.

Results

Several surface interaction mechanisms promote the anchoring of H. pylori on C. albicans, cell co-aggregation, and polymicrobial biofilm formation, main identified interactions were: (i) hydrophobic interactions between non-polar peptide chains and lipid structures, characterized by θ_w among 84.9 ± 1.6 (γ = 22.78 mJ/m² with 95.3 of dispersive contribution) and 76.6 ± 3.8 (γ = 17.34 mJ/m², 40.2 of dispersive contribution) for C. albicans and H. pylori, respectively, (ii) hydrogen bonds between surface components of yeast and bacterium (e.g., -S-H⋅⋅⋅NH₂- or -S-H⋅⋅⋅O[bond, double bond]CO-) and (iii) thiol-mediated surface interactions identified by displacements to lower wavenumbers (Δv = 5 cm^-1). Evidence of internalization and electrostatic interactions were not evidenced. All observations were congruent with the biofilm formation, including the identification of small-size biostructures (i.e., 122-459 nm) associated with extracellular proteins, extracellular DNA, or outer membrane vesicles were observed characteristic of biofilm formation.

Conclusion

It is concluded that biofilm is formed by co-aggregation after anchoring of H. pylori on C. albicans. Several surface interactions were associated with the prevalence of H. pylori, the possibility to find C. albicans in the stomach epithelium infected by H. pylori, but also, strength interactions could be interfering in experimental observations associated with bacterial-DNA detection in culture mixtures.

Long term outcomes of sporadic large fundic gland polyps: a single-center experience

BACKGROUND AND STUDY AIMS

Sporadic fundic gland polyps (FGP) are the most common type of gastric polyp, reported in 0.8%-1.9% of patients undergoing Esophagogastroduodenoscopy (EGD). Data on long-term outcomes of large FGP is limited. We aim to study the natural history of sporadic large (≥ 10 mm) FGPs.

PATIENTS AND METHODS

All adults who underwent EGD for any indication from April 2014 to December 2019 at a tertiary care center were retrospectively assessed, and patients with FGP (≥10mm) were identified. Data on baseline characteristics and long-term outcomes were recorded. Follow-up data were recorded for patients who underwent repeat endoscopy to evaluate for rates of dysplasia and cancer.

RESULTS

A total of 4,000 patients with a diagnosis of FGP were screened and 132 large, biopsy-proven FGPs were included in the final analysis. The most common indication for EGD was gastroesophageal reflux disease (61%). During a follow-up period of 3.2 years, the rate of dysplasia, was 4.0%. Subgroup analysis based on size (10-19 mm and ≥ 20 mm) showed no significant difference in overall outcomes.

CONCLUSION

Repeat EGDs for surveillance should not be routinely performed since large (≥10 mm) sporadic FGPs are mostly benign without significant malignant potential.

Diagnostic Value of Serum Pepsinogen Levels for Screening Gastric Cancer and Atrophic Gastritis in Asymptomatic Individuals: A Cross-Sectional Study

Background

Pepsinogens (PGs) can be used for gastric cancer (GC) screening, but the cutoff levels vary among studies, and PG levels are influenced by numerous factors. The aim of this article is to examine the diagnostic value of PG levels and Helicobacter pylori (Hp) status for GC and atrophic gastritis screening in asymptomatic individuals undergoing health checkup in China.

Patients and Methods

This was a multicenter cross-sectional study of subjects who underwent health checkup from 10/2016 to 10/2018 at nine International Healthcare Centers in China. All participants underwent gastroscopy and pathological examination, serum PG, ¹³C-urea breath test, and/or Hp serological current infection marker rapid test, all on the same day. PG-related parameters were analyzed in different Hp subgroups and regions.

Results

The patients were grouped as non-atrophic (NAG, n = 1,590), mild to moderate atrophic (MAG, n = 273), severe atrophic (SAG, n = 49), and GC (n = 10). The serum PG levels in these groups decreased with increasing pathological severity. In the same pathological groups, PGI and PGII levels were higher in the Hp-positive subgroup, while PGR (PGI/PGII ratio) was lower (P < 0.05). The best cutoff values for atrophy diagnosis were PGI ≤73.1 ng/ml and PGR ≤9.8, for severe atrophy were PGI ≤63.9 ng/ml and PGR ≤9.09, and for GC was PGR ≤4.7 (all P < 0.05 and area under the curve >0.7). The cutoff points varied with Hp status and China regions.

Conclusion

Serum PG levels might be used for the screening of gastric atrophic gastritis lesions. The results suggest that different cutoff values should possibly be used in different Hp status groups and geographical regions, but it will have to be validated in future studies. Future studies should also examine the value of PG levels for GC detection.

Gastric epithelial attachment of Helicobacter pylori induces EphA2 and NMHC-IIA receptors for Epstein-Barr virus

Epstein-Barr virus (EBV)-associated gastric cancer belongs to 1 of the 4 subtypes of gastric cancer and accounts for 10% of total gastric cancers. However, most cases of gastric cancer have a history of Helicobacter pylori infection. Therefore, we investigated the possibility that H. pylori infection promotes the development of EBV-associated gastric cancer. H. pylori was exposed to principal EBV receptor, CD21, negative gastric epithelial cells, and then infected with EBV recombinant expressing enhanced green fluorescent protein. Changes in EBV infectivity due to prior H. pylori exposure were analyzed using flow cytometry. The treatment of gastric epithelial cells with H. pylori increased the efficiency of EBV infection. An increase was also observed when CagA-deficient, VacA-deficient, and FlaA-deficient H. pylori strains were used, but not when cag pathogenicity island-deficient H. pylori was used. The treatment of epithelial cells with H. pylori induced the expression of accessory EBV receptors, EphA2 and NMHC-IIA, and increased the efficiency of EBV infection depending on their expression levels. When gastric epithelial cells were treated with EPHA2 or NMHC-IIA siRNA, EBV infection via H. pylori attachment was decreased. The adhesion of H. pylori induced the expression of accessory EBV receptors in gastric epithelial cells and increased the efficiency of EBV infection.

Helicobacter pylori and Gastric Cancer

Helicobacter pylori is present in approximately one-half of the world's population. There are significant differences in prevalence based on region, age, race/ethnicity, and socioeconomic status. H pylori is the most common cause of infection-related cancers. Studies have demonstrated the relationship between H pylori infection and gastric adenocarcinoma and mucosa-associated lymphoid tissue lymphoma. H pylori has features and enzymatic properties allowing it to survive in the acidic stomach environment, and has specific virulence factors that promote an increased risk of gastric pathology. Eradication of H pylori is first-line therapy for mucosa-associated lymphoid tissue lymphoma and decreases the risk of gastric adenocarcinoma.

Gastric Adenocarcinomas and Signet-Ring Cell Carcinoma: Unraveling Gastric Cancer Complexity through Microbiome Analysis-Deepening Heterogeneity for a Personalized Therapy

Gastric cancer (GC) is the fifth most prevalent cancer worldwide and the third leading cause of global cancer mortality. With the advances of the omic studies, a heterogeneous GC landscape has been revealed, with significant molecular diversity. Given the multifaceted nature of GC, identification of different patient subsets with prognostic and/or predictive outcomes is a key aspect to allow tailoring of specific treatments. Recently, the involvement of the microbiota in gastric carcinogenesis has been described. To deepen this aspect, we compared microbiota composition in signet-ring cell carcinoma (SRCC) and adenocarcinoma (ADC), two distinct GC subtypes. To this purpose, 10 ADC and 10 SRCC and their paired non-tumor (PNT) counterparts were evaluated for microbiota composition through 16S rRNA analysis. Weighted and unweighted UniFrac and Bray-Curtis dissimilarity showed significant community-level separation between ADC and SRCC. Through the LEfSe (linear discriminant analysis coupled with effect size) tool, we identified potential microbial biomarkers associated with GC subtypes. In particular, SRCCs were significantly enriched in the phyla Fusobacteria, Bacteroidetes, Patescibacteria, whereas in the ADC type, Proteobacteria and Acidobacteria phyla were found. Overall, our data add new insights into GC heterogeneity and may contribute to deepening the GC classification.

Awareness and attitudes regarding Helicobacter pylori infection in Chinese physicians and public population: A national cross-sectional survey

BACKGROUND

There is a lack of reports on the awareness of Helicobacter pylori (H pylori) prevention and treatment in the general Chinese population. And whether the knowledge level will affect their action toward screening was unknown. This study aimed to conduct a national survey on the knowledge, attitudes, and practice regarding H pylori infection in Chinese physicians and the public.

METHODS

This was an Internet-based survey of the general Chinese population and Chinese physicians from different specialties, carried out from January to February 2019. Both surveys (general population's and physicians') included questions to assess the knowledge and attitudes toward H pylori and its action.

RESULTS

A total of 3211 people and 546 physicians were enrolled. In the population, the proportion of subjects who answered correctly to all questions about H pylori's infectivity was only 16%, and that for H pylori's harmfulness and that for H pylori preventive measures were 35% and 43.6%, respectively. In general, physicians had a better understanding of H pylori's harmfulness (83.9%) than the other population. The vast majority of the surveyed population (87.0%) and physicians (82.2%) supported a national H pylori screening plan to prevent gastric cancer. The support ratio paralleled with the overall knowledge level. Unexpectedly, gastroenterologists tend to have a relatively low support rate for H pylori screening than non-gastroenterologists (58.2% vs 84.2%, P < .001), which may be related to consideration of heavy medical burden (67.3%).

CONCLUSIONS

The general population in China has relatively insufficient awareness of H pylori, which is incompatible with the highly infectious status. More works on health education are needed to improve the knowledge of this gastric pathogen.

Helicobacter pylori eradication for the prevention of gastric neoplasia

BACKGROUND

Gastric cancer is the third most common cause of cancer death worldwide. Individuals infected with Helicobacter pylori have a higher likelihood of developing gastric cancer than individuals who are not infected. Eradication of H. pylori in healthy asymptomatic individuals in the general population may reduce the incidence of gastric cancer, but the magnitude of this effect is unclear.

OBJECTIVES

To assess the effectiveness of eradication of H. pylori in healthy asymptomatic individuals in the general population in reducing the incidence of gastric cancer.

SEARCH METHODS

We identified trials by searching the Cochrane Central Register of Controlled Trials (CENTRAL; 2020, Issue 1), MEDLINE (1946 to February 2020), and EMBASE (1974 to February 2020). We handsearched reference lists from trials selected by electronic searching to identify further relevant trials. We handsearched published abstracts from conference proceedings from the United European Gastroenterology Week (published in Gut) and Digestive Disease Week (published in Gastroenterology) between 2001 and 2019. We contacted members of the Cochrane Upper Gastrointestinal and Pancreatic Diseases Review Group and experts in the field and asked them to provide details of outstanding clinical trials and any relevant unpublished materials.

SELECTION CRITERIA

We analysed randomised controlled trials comparing at least one week of H. pylori therapy with placebo or no treatment in preventing subsequent development of gastric cancer in otherwise healthy and asymptomatic H. pylori-positive adults. Trials had to follow up participants for at least two years and needed to have at least two participants with gastric cancer as an outcome. We defined gastric cancer as any gastric adenocarcinoma, including intestinal (differentiated) or diffuse (undifferentiated) type, with or without specified histology.

DATA COLLECTION AND ANALYSIS

We collected data on incidence of gastric cancer, incidence of oesophageal cancer, deaths from gastric cancer, deaths from any cause, and adverse effects arising due to therapy.

MAIN RESULTS

Six trials met all our eligibility criteria and provided extractable data in the previous version. Following our updated search, one new RCT was identified, meaning that seven trials were included in this updated review. In addition, one previously included trial provided fully published data out to 10 years, and another previously included trial provided fully published data out to 22 years of follow-up. Four trials were at low risk of bias, one trial was at unclear risk, and two trials were at high risk of bias. Six trials were conducted in Asian populations. In preventing development of subsequent gastric cancer, H. pylori eradication therapy was superior to placebo or no treatment (RR 0.54, 95% confidence interval (CI) 0.40 to 0.72, 7 trials, 8323 participants, moderate certainty evidence). Only two trials reported the effect of eradication of H. pylori on the development of subsequent oesophageal cancer. Sixteen (0.8%) of 1947 participants assigned to eradication therapy subsequently developed oesophageal cancer compared with 13 (0.7%) of 1941 participants allocated to placebo (RR 1.22, 95% CI 0.59 to 2.54, moderate certainty evidence). H. pylori eradication reduced mortality from gastric cancer compared with placebo or no treatment (RR 0.61, 95% CI 0.40 to 0.92, 4 trials, 6301 participants, moderate certainty evidence). There was little or no evidence in all-cause mortality (RR 0.97, 95% CI 0.85 to 1.12, 5 trials, 7079 participants, moderate certainty evidence). Adverse events data were poorly reported.

AUTHORS' CONCLUSIONS

We found moderate certainty evidence that searching for and eradicating H. pylori reduces the incidence of gastric cancer and death from gastric cancer in healthy asymptomatic infected Asian individuals, but we cannot necessarily extrapolate this data to other populations.

Clinical significance and influencing factors of linked color imaging technique in real-time diagnosis of active Helicobacter pylori infection

Background:

Determining the Helicobacter pylori (H. pylori) infection state during the gastroscopic process is important but still challenging. The linked color imaging (LCI) technique might emphasize the mucosal color change after H. pylori infection, which might help the diagnosis. In the present study, we aimed to compare the LCI technique with traditional white light imaging (WLI) endoscopy for diagnosing active H. pylori infection.

Methods:

We collected and analyzed gastroscopic images from 103 patients in our hospital from November 2017 to March 2018, including both LCI and WLI modes. All images were randomly disordered and independently evaluated by four endoscopists who were blinded to the H. pylori status of patients. In addition, the H. pylori state was determined by both rapid urease test and pathology staining. The sensitivity, specificity, positive prediction value (PPV), and negative prediction value (NPV) were calculated for the detection of H. pylori infection. Moreover, the kappa value and interclass correlation coefficient (ICC) were used to evaluate the inter-observer variety by SPSS 24.0 software.

Results:

Of the 103 enrolled patients, 27 of them were positive for H. pylori infection, while the 76 patients were negative. In total, 388 endoscopic images were selected, including 197 WLI and 191 LCI. The accuracy rate for H. pylori evaluation in the corpus LCI group was significantly higher than other groups (81.2% vs. 64.3%–76.5%, χ² = 34.852, P < 0.001). Moreover, the corpus LCI group had the optimal diagnostic power with the sensitivity of 85.41% (95% confidence interval [CI]: 76.40%–91.51%), the specificity of 79.71% (95% CI: 74.38%–84.19%), the PPV of 59.42% (95% CI: 50.72%–67.59%), and the NPV of 94.02% (95% CI: 89.95%–96.56%), respectively. The kappa values between different endoscopists were higher with LCI than with WLI (0.433–0.554 vs. 0.331–0.554). Consistently, the ICC value was also higher with LCI than with WLI (0.501 [95% CI: 0.429–0.574] vs. 0.397 [95% CI: 0.323–0.474]). We further analyzed the factors that might lead to misjudgment, revealing that active inflammation might disturb WLI judgment (accuracy rate: 58.70% vs. 76.16%, χ² = 21.373, P < 0.001). Atrophy and intestinal metaplasia might affect the accuracy of the LCI results (accuracy rate: 66.96% vs. 73.47%, χ² = 2.027; 68.42% vs. 73.53%, χ² = 1.594, respectively); however, without statistical significance (P = 0.154 and 0.207, respectively).

Conclusions:

The application of LCI at the corpus to identify H. pylori infection is reliable and superior to WLI. The inter-observer variability is lower with LCI than with WLI.

Trial registration:

Chinese Clinical Trial Registry: ChiCTR1800016730; http://www.chictr.org.cn/showproj.aspx?proj=28400

Cyclooxigenase-2 and osteopontin in gastric pre-neoplastic lesions in relation to H-pylori infection and grade of inflammation

The association between Helicobacter-pylori-induced inflammation and gastric adenocarcinoma is well documented and it has been suggested that the pro-mitotic and apoptotic effect of Cyclooxygenase-2 and Osteopontin on the epithelial cells of the gastric mucosa may have a role in carcinogenesis of the gastric mucosa. The aim of this study was to determine the expression of Cyclooxygenase-2 and Osteopontin in normal gastric mucosa, mucosa with gastritis and gastric mucosa with intestinal metaplasia, in relation to Helicobacter-pylori infection and grade of inflammation. Immunohistochemistry was performed on 108 gastric biopsies in order to detect Cyclooxygenase-2 and Osteopontin expression. The intensity and percentage of staining were evaluated using the H-Score, and its association with grade of inflammation, Helicobacter pylori infection and intestinal metaplasia was determined. Expression of Cyclooxygenase-2 and Osteopontin was higher in gastric biopsies (values shown respectively) with Helicobacter-pylori infection (179.9/142.3), intestinal metaplasia (208.8/179.3) or higher grades of inflammation (190/135.7) in comparison to normal gastric mucosa (100.7/80) or mild grade of inflammation (128.4/128.4), (p<0.05).There is an overexpression of Cyclooxygenase-2 and Osteopontin in gastric mucosa with H. pylori infection, intestinal metaplasia and high grades of inflammation, suggesting a constant up-regulation of protein expression in response to the inflammatory process generated by a Helicobacter-pylori infection, leading to the development of intestinal metaplasia.

Reverse hybrid therapy achieves a similar eradication rate as standard hybrid therapy for Helicobacter pylori infection

BACKGROUND

Reverse hybrid therapy is a simplified hybrid treatment for Helicobacter pylori infection. It achieves a higher eradication rate than standard triple therapy. This study aimed to compare the efficacies of reverse hybrid and hybrid therapies in the treatment of H. pylori infection.

METHODS

From September 2008 to September 2017, 490 H. pylori-infected patients who received 14 days of reverse hybrid therapy (proton pump inhibitor plus amoxicillin for 14 days and clarithromycin plus metronidazole for the initial 7 days; n = 252) or hybrid therapy (proton pump inhibitor plus amoxicillin for 14 days and clarithromycin plus metronidazole for the final 7 days; n = 238) were included in this retrospective cohort study. Helicobacter pylori status was examined 6-8 weeks after therapy.

RESULTS

The eradication rates of the reverse hybrid and hybrid therapies by modified intention-to-treat analysis were comparable (96.4% vs 96.6%; p = 0.899). There were no differences in the efficacy of eradication between therapies for clarithromycin-resistant strains (87.0% vs 90.0%) or metronidazole-resistant strains (97.7% vs 100.0%). In addition, there were comparable frequencies of adverse events for both treatments (18.7% vs 13.0%) and treatment adherence (94.4% vs 97.1%).

CONCLUSION

Reverse hybrid therapy can achieve a similar eradication rate to hybrid therapy for H. pylori infection.

Evaluation of cell-penetrating peptide-peptide nucleic acid effect in the inhibition of cagA in Helicobacter pylori

Helicobacter pylori is the most common cause of chronic infection in human and is associated with gastritis, peptic ulcer disease, and adenocarcinoma of mucosa-associated lymphoid tissue cells. Peptide nucleic acid (PNA) is a synthetic compound, which can inhibit the production of a particular gene. This study aimed to investigate the effect of PNA on inhibiting the expression of cagA. After confirmation of the desired gene by polymerase chain reaction (PCR), the antisense sequence was designed against cagA gene. The minimum inhibitory concentrations of conjugated PNA against H. pylori was determined. The effect of the compound on the expression level of the cagA was investigated in HT29 cell culture using real-time PCR. The results showed 2 and 3 log reduction in bacterial count after 8- and 24-h treatment with 4 and 8 μM of the compound, respectively. The lowest expression level of the cagA gene was observed at a concentration of 8 μM after 6 h. The results of this study showed that cell-penetrating peptide antisense can be employed as effective tools for inhibiting the target gene mRNA for various purposes. Moreover, further research is necessary to assess the potency, safety, and pharmacokinetics of CPP-PNAs for clinical prevention and treatment of infections due to H. pylori.

Molecular anatomy and pathogenic actions of Helicobacter pylori CagA that underpin gastric carcinogenesis

Chronic infection with Helicobacter pylori cagA-positive strains is the strongest risk factor for gastric cancer. The cagA gene product, CagA, is delivered into gastric epithelial cells via the bacterial type IV secretion system. Delivered CagA then undergoes tyrosine phosphorylation at the Glu-Pro-Ile-Tyr-Ala (EPIYA) motifs in its C-terminal region and acts as an oncogenic scaffold protein that physically interacts with multiple host signaling proteins in both tyrosine phosphorylation-dependent and -independent manners. Analysis of CagA using in vitro cultured gastric epithelial cells has indicated that the nonphysiological scaffolding actions of CagA cell-autonomously promote the malignant transformation of the cells by endowing the cells with multiple phenotypic cancer hallmarks: sustained proliferation, evasion of growth suppressors, invasiveness, resistance to cell death, and genomic instability. Transgenic expression of CagA in mice leads to in vivo oncogenic action of CagA without any overt inflammation. The in vivo oncogenic activity of CagA is further potentiated in the presence of chronic inflammation. Since Helicobacter pylori infection triggers a proinflammatory response in host cells, a feedforward stimulation loop that augments the oncogenic actions of CagA and inflammation is created in CagA-injected gastric mucosa. Given that Helicobacter pylori is no longer colonized in established gastric cancer lesions, the multistep nature of gastric cancer development should include a “hit-and-run” process of CagA action. Thus, acquisition of genetic and epigenetic alterations that compensate for CagA-directed cancer hallmarks may be required for completion of the “hit-and-run” process of gastric carcinogenesis.

Helicobacter pylori (HP) infection alone, but not HP-induced atrophic gastritis, increases the risk of gastric lymphoma: a case-control study in Japan

Infection with Helicobacter pylori (H. pylori) is associated with an increased risk of gastric malignant lymphoma. The chronic inflammation of gastric mucosa by H. pylori infection induces lymphomagenesis. Although this chronic mucosal inflammation also results in atrophic gastritis, evidence supporting the possible significance of atrophic gastritis in gastric lymphomagenesis is scarce. Here, to evaluate the association between gastric mucosal atrophy and the risk of gastric lymphoma, we conducted a matched case-control study at Aichi Cancer Center focusing on the attribution of H. pylori infection status and pepsinogen (PG) serum levels. In total, 86 patients with gastric lymphoma (including 49 cases of extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma) and 24 cases of diffuse large B cell lymphoma (DLBCL)) and 1720 non-cancer controls were included. Odds ratios (ORs) and 95% confidence intervals (CIs) were assessed by conditional logistic regression analysis with adjustment for potential confounders. Results failed to show a statistically significant association between atrophic gastritis and the risk of gastric lymphoma. The adjusted ORs of positive atrophic gastritis relative to negative for overall gastric lymphoma, MALT lymphoma, DLBCL, and other lymphomas were 0.77 (95% CI 0.45-1.33), 0.65 (0.30-1.39), 1.03 (0.38-2.79), and 0.84 (0.22-3.29), respectively. In contrast, a positive association between overall gastric lymphoma and H. pylori infection was observed (OR = 2.14, 95% CI 1.30-3.54). A consistent association was observed for MALT lymphoma, DLBCL, and other lymphomas with ORs of 1.96 (1.00-3.86), 1.92 (0.74-4.95), and 5.80 (1.12-30.12), respectively. These findings suggest that H. pylori infection triggers gastric lymphoma but that epithelial changes due to atrophic gastritis do not inherently affect the development of gastric lymphoma.

Cancer Stem-Cell Marker CD44v9-Positive Cells Arise From Helicobacter pylori-Infected CAPZA1-Overexpressing Cells

BACKGROUND & AIMS

CD44 variant 9 (CD44v9)-positive cancer stem-like cells strongly contribute to the development and recurrence of gastric cancer. However, the origin of CD44v9-positive cells is uncertain.

METHODS

CD44v9, β-catenin, and epithelial splicing regulatory protein 1 signals were assessed by real-time reverse-transcription polymerase chain reaction, immunoblot analysis, or immunofluorescence microscopy. Capping actin protein of muscle Z-line α subunit 1 (CAPZA1) expression was assessed by immunoblot analysis or immunohistochemical analysis of Mongolian gerbils' gastric mucosa or human biopsy specimens. Levels of oxidative stress were assessed by measuring malondialdehyde and protein carbonylation. Histone H3 acetylation levels in the CAPZA1 proximal promoter region were measured by using chromatin immunoprecipitation analysis with an antibody against the acetylated histone H3 in human gastric carcinoma cell line (AGS) cells.

RESULTS

CD44v9 is expressed in CAPZA1-overexpressing cells in human gastric cancer tissues. CAPZA1 overexpression enhanced expression of β-catenin, which is a transcription factor for CD44, and epithelial splicing regulatory protein 1, which increases alternative splicing of CD44 to generate CD44v9. CAPZA1-overexpressing cells after cytotoxin-associated gene A accumulation showed CD44v9 expression by inducing nuclear accumulation of β-catenin, concomitant with the enhancement of expression of Sal-like protein 4 and Krüppel-like factor 5, which encode reprogramming factors. Oxidative stress increased the CAPZA1 expression in AGS cells through the enhancement of histone H3 acetylation of CAPZA1 promoter. CAPZA1 expression was increased depending on oxidative stress in H pylori-infected gastric mucosa.

CONCLUSIONS

CD44v9 expression is evoked from CAPZA1-overexpressing cells after accumulation of cytotoxin-associated gene A. Our findings provide important insights into the mechanisms underlying the development of CD44v9-positive cells.

Efficacy and Long-Term Safety of H. pylori Eradication for Gastric Cancer Prevention

Helicobacter pylori (H. pylori) has been shown to be a causal factor of gastric cancer in cohort studies and animal models. Meta-analysis of case-control studies nested within prospective cohorts showed that H. pylori infection was associated with a 5.9-fold increased risk of non-cardia gastric cancer. Prospective cohort studies showed that gastric cancer developed in 1–4% of H. pylori-infected subjects. Gastric cancer was successfully induced in Mongolian gerbils and insulin-gastrin (INS-GAS) transgenic mice after inoculation of H. pylori. Meta-analysis of randomized control trials also showed that eradication of H. pylori may reduce the risk of gastric cancer. However, there are several concerns regarding the widespread use of antibiotics to prevent gastric cancer, including the emergence of antibiotic resistance and the perturbation of gut microbiota after H. pylori eradication. Recent studies showed that eradication of H. pylori resulted in an increase in the bacterial diversity and restoration of the relative abundance of other bacteria to levels similar to H. pylori non-infected subjects in the gastric microbiota. The administration of antibiotics may also alter the composition of intestinal microbiota. The α-diversity and β-diversity of fecal microbiota are significantly altered immediately after H. pylori eradication but are gradually restored to levels similar to those before therapy. Yet, the rate of recovery varies with regimens. The diversity was restored at week 8 after triple therapy but was not yet fully recovered at 1 year after concomitant and quadruple therapies. Some studies showed that supplementation of probiotics may reduce the dysbiosis during H. pylori eradication therapy. Although some earlier studies showed high levels of macrolide resistance after triple therapy, recent studies showed that the increased antibiotic resistance rate may be restored 2–12 months after eradication therapy. These results collectively provide evidence of the long-term safety of H. pylori eradication. Yet, more prospective cohort studies and randomized trials are warranted to assess the efficacy and long-term safety of H. pylori eradication for gastric cancer prevention.

The Prevalence and Risk Factors of Gastric Polyp in Asymptomatic Patients Receiving Health Examination

Background

To determine the risk factors and prevalence of asymptomatic gastric polyps in the general population of Taiwan.

Methods

Consecutive asymptomatic individuals completing a health examination during October 2015–March 2016 were enrolled in the study and subjected to upper GI endoscopy. Their demographic data and medical history were collected, and the prevalence of gastric polyps was calculated. The risk factors of gastric polyps were identified by analyzing these data through univariate and multivariate logistic regression.

Results

Gastric polyp prevalence in the study population was 29.8%. Age range of 45–60 years, current smoking, and lack of regular exercise were found to be significantly associated with gastric polyps, whereas age range of 45–60 years (relative risk [RR], 1.59; 95% confidence interval [CI], 1.06–2.40) and current smoking (RR, 1.63; 95% CI, 1.04–2.55) were found to be independent predictors for gastric polyps.

Conclusions

In Taiwan, asymptomatic gastric polyps have a prevalence of 29.8%. Age range of 45–60 years and current smoking may increase the risk of asymptomatic gastric polyps.

Microbiota and gastrointestinal cancer

Gut microbiota plays important roles in many diseases, including cancer. It may promote carcinogenesis by inducing oxidative stress, genotoxicity, host immune response disturbance, and chronic inflammation. Colorectal cancer, hepatocellular carcinoma, and gastric cancer are the major gastrointestinal tract cancers in Taiwan. The microbiota detected in patients with tubular adenoma and villous/tubulovillous polyps is different from that in healthy controls and patients with hyperplastic polyps. Normalization of the microbiota is observed in patients after colorectal cancer treatment. Furthermore, the liver is exposed to microbiota-associated molecular patterns (MAMPs), bacterial metabolites, and toxins, as it is anatomically connected to the gut via the portal vein. Patients with cirrhosis have significantly higher plasma endotoxin levels than healthy controls. Helicobacter pylori is a well-established risk factor for gastric cancer. Some nitrosating bacteria convert nitrogen compounds in gastric fluid to potentially carcinogenic N-nitroso compounds, which also contribute to gastric cancer development. Growing evidence demonstrates that gut microbiota promotes carcinogenesis. In this review, we discuss the mechanisms and types of microbiota changes involved in these gastrointestinal cancers and the future treatment choices.

Grading of Atrophic Gastritis is Useful for Risk Stratification in Endoscopic Screening for Gastric Cancer

OBJECTIVES

In order to screen for gastric cancer effectively, its interval should be set according to the risk. This study aimed to determine whether risk stratification is possible using the data obtained from medical examination or endoscopic findings.

METHODS

First, subjects who underwent both cancer screening and medical examination from 2009 to 2015 and underwent cancer screening once more by 2016 were studied. Data such as the lipid profile and history of smoking obtained during the medical examination, and the grade of atrophy and presence of peptic ulcers were studied using multivariate analysis. Next, subjects who underwent cancer screening twice or more between 2009 and 2015 with or without medical examinations were studied to analyze any correlation between the grade of atrophy and cancer occurrence using univariate analysis. In both studies, the status of Helicobacter pylori (HP) infection was determined.

RESULTS

In the multivariate analysis, 9378 subjects were included. Aging, advanced atrophy, presence of ulcers, and uric acid levels were identified as risk factors. Among subjects who underwent successful HP eradication therapy, advanced atrophy and aging were observed to be crucial risk factors. In the univariate analysis, there were 12,941 subjects. Gastric cancer occurred more frequently in the more severe atrophy group (P < 0.001). The annual rate of cancer occurrence in the most severe atrophy group was 0.31%, which was approximately thrice as that in the less atrophy group.

CONCLUSIONS

Risk stratification was possible based on endoscopic examination alone. The interval should be set depending on each case.

The incidence of neoplasia in patients with autoimmune metaplastic atrophic gastritis: a renewed call for surveillance

Background

Autoimmune metaplastic atrophic gastritis (AMAG) is an immune-mediated process that may lead to pernicious anemia (PA) and an increased risk of gastric cancer. Although some literature supports 3- or 5-year endoscopic surveillance for gastric cancer in patients with PA, no formal guidance exists for the general AMAG population. We sought to identify the prevalence and incidence rates of dysplasia or adenocarcinoma in patients with AMAG in order to clarify endoscopic best practices.

Methods

A retrospective study of 150 patients diagnosed with AMAG on endoscopic gastric biopsy between 1/2010 and 11/2015 was performed at a tertiary medical center. Clinical and pathologic data were obtained in order to calculate the prevalence and the incidence rate of dysplasia or adenocarcinoma.

Results

The cohort was predominantly female (82%) and white (61%), with median age 64 years. PA was present in 47% of patients. On index endoscopy, the prevalence of adenocarcinoma was 5.3%. A total of 59 patients with AMAG, but without neoplasia on initial biopsy, underwent subsequent endoscopic surveillance. Two patients, both of whom had confirmed PA, developed adenocarcinoma. The incidence rate of adenocarcinoma among this group was 14.2 cases per 1000 person-years, which far exceeds that of the general population (0.073 per 1000 person-years) based on Surveillance, Epidemiology, and End Results data.

Conclusions

AMAG is associated with a high prevalence and incidence of gastric cancer, and endoscopic surveillance should be considered. Prospective cohort studies and cost effectiveness analyses are needed to better estimate cancer risk and recommended endoscopic surveillance intervals in these patients.

Risk of gastric cancer among patients with gastric intestinal metaplasia

Plenty of studies have assessed the association between intestinal metaplasia (IM) and gastric cancer risk, while the results were inconsistent. We aimed to assess the risk of gastric cancer among patients with IM. Systematic literature searches were conducted in PubMed, Embase and Cochrane databases. Baseline characteristics and outcomes from the included studies were extracted independently by two investigators. Either a fixed-effects or a random-effects model was used to composite the pooled OR for gastric cancer risk. Finally, a total of 21 studies, which comprised 402,636 participants and 4,535 gastric cancer patients, were finally included in the current meta-analysis. Compared with those participants without IM, IM patients were at a higher risk of gastric cancer (pooled OR = 3.58, 95% CI 2.71-4.73). We observed that incomplete IM (pooled OR = 9.48, 95% CI 4.33-20.78) but not complete IM (pooled OR = 1.55, 95% CI 0.91-2.65) was significantly associated with a higher gastric cancer risk. Besides, it appeared that gastric cancer risk was higher among patients with IM in the corpus (pooled OR = 7.39, 95% CI 4.94-11.06) than those with IM in the antrum only (pooled OR = 4.06, 95% CI 2.79-5.91). And the pooled ORs for gastric noncardia cancer and gastric cardia cancer were 4.98 (95% CI 3.12-7.95) and 1.93 (95% CI 1.15-3.24), respectively. In conclusion, patients with IM were at a higher risk of gastric cancer, especially for incomplete IM and IM in the corpus. The current evidence supports the use of IM subtypes in the surveillance of gastric cancer.

Pathologic Features of Infectious Gastritis

This manuscript presents a review of infectious causes of gastritis aimed at the practicing anatomic pathologist. We shall highlight unique histologic findings and clinical attributes that will assist those analyzing endoscopically obtained mucosal biopsies of the stomach or resection specimens.

Characteristics and predictors of gastric cancer after Helicobacter pylori eradication

Helicobacter pylori (H. pylori) eradication can reduce gastric cancer. However, gastric cancer still develops after eradication, and cases who received eradication therapy are increasing. In this study, we have reviewed the characteristics and predictors of primary gastric cancer developing after H. pylori eradication. In terms of the characteristics, endoscopic, histologic, and molecular characteristics are reported. Endoscopically, gastric cancer after eradication is often depressed-type and shows a gastritis-like appearance, which sometimes makes the diagnosis difficult. Histologically, most gastric cancer after eradication is intestinal type, and non-neoplastic epithelium, also called epithelium with low-grade atypia, is frequently seen over the tumor, which is presumably the cause of the endoscopic gastritis-like appearance. As for molecular characteristics, some markers, such as Ki67, MUC2, and Wnt5a expression, are lower in cancer from patients in whom H. pylori has been eradicated. In terms of predictors, several Japanese studies have reported that severe endoscopic atrophy at eradication is a risk factor for gastric cancer development. Histologic intestinal metaplasia, especially in the corpus, and long-term use of proton pump inhibitors, are also reported as risk factors for gastric cancer after H. pylori eradication. These studies on the characteristics and predictors of gastric cancer development will become the cornerstone for establishing a novel surveillance program based on the gastric cancer risk stratification specific to H. pylori-eradicated patients.

Anti-Helicobacter pylori and Anti-Inflammatory Effects and Constituent Analysis of Modified Xiaochaihutang for the Treatment of Chronic Gastritis and Gastric Ulcer

Chronic gastritis and gastric ulcers are prevalent throughout the world and are considered to be a global health problem. Modified Xiaochaihutang (MXCHT) prescription is broadly used in traditional medicine hospital for the treatment of gastritis. In order to assess the anti-Helicobacter pylori (H. pylori) effect of MXCHT, agar diffusion method in vitro and fluid dilution method for the minimal inhibitory concentration (MIC) were established. The anti-inflammatory effects were then evaluated using mouse ear edema model and rat paw edema model. The ethanol-induced gastric ulcer method was employed to verify the gastroprotective effect of active extracts in MXCHT. HPLC-TOF-MS/MS was used for analyzing the possible active constituents after oral administration of effective extracts in ethanol-induced gastric ulcer models. MXCHT and 4 different extracts of the bacterial inhibition diameter and MIC were dramatically decreased compared with control group, showing anti-Helicobacter pylori effects. High dose groups of MXCHT, water extract, EtOAc extract, and n-BuOH extract displayed significant anti-inflammatory effects in xylene-induced mouse ear edema model and carrageenan-induced rat paw edema model test. MXCHT and all active extracts exhibited gastroprotective activity and prevented gastric lesions induced by ethanol in rats. 4 prototype components and 4 metabolites were identified after oral administration of EtOAc extract. In addition, 6 prototype components and 6 metabolites were identified in n-BuOH extract. MXCHT, EtOAc extract, and n-BuOH extract demonstrate gastroprotective effects through anti-Helicobacter pylori and anti-inflammatory activities. Thus, this prescription may be a suitable natural source for the prevention and treatment of chronic gastritis and gastric ulcers.

Gastric microbiota: tracing the culprit

The gastric environment has been long time considered bacteria-free, but the discovery of Helicobacter pylori (H. pylori) in 1982 superseded this conception. Over the last decades new diagnostic methods have been developed, starting with culture-dependent and advancing to culture-independent ones. These modern techniques provide new insight into the composition and influence of this ecosystem on the entire gastrointestinal tract. H. pylori is no longer considered the only microorganism in the stomach, other non-H. pylori microbial species may populate the same environment and exercise their role. Current knowledge suggests possible links of these bacteria with gastroduodenal diseases, such as peptic ulcer and gastric cancer but most of them need further scientific evidence. This review summarizes current information on these complex interrelations between gastric microbial communities and host in health and disease.

Structure and function of Helicobacter pylori CagA, the first-identified bacterial protein involved in human cancer

Chronic infection with Helicobacter pylori cagA-positive strains is the strongest risk factor of gastric cancer. The cagA gene-encoded CagA protein is delivered into gastric epithelial cells via bacterial type IV secretion, where it undergoes tyrosine phosphorylation at the Glu-Pro-Ile-Tyr-Ala (EPIYA) motifs. Delivered CagA then acts as a non-physiological scaffold/hub protein by interacting with multiple host signaling molecules, most notably the pro-oncogenic phosphatase SHP2 and the polarity-regulating kinase PAR1/MARK, in both tyrosine phosphorylation-dependent and -independent manners. CagA-mediated manipulation of intracellular signaling promotes neoplastic transformation of gastric epithelial cells. Transgenic expression of CagA in experimental animals has confirmed the oncogenic potential of the bacterial protein. Structural polymorphism of CagA influences its scaffold function, which may underlie the geographic difference in the incidence of gastric cancer. Since CagA is no longer required for the maintenance of established gastric cancer cells, studying the role of CagA during neoplastic transformation will provide an excellent opportunity to understand molecular processes underlying "Hit-and-Run" carcinogenesis.

Vonoprazan versus conventional proton pump inhibitor-based triple therapy as first-line treatment against Helicobacter pylori: A multicenter retrospective study in clinical practice

OBJECTIVE

Vonoprazan is a potassium-competitive acid blocker, a new type of acid-suppressing drug, and has recently become available for peptic ulcers, gastroesophageal reflux disease, and Helicobacter pylori (H. pylori) eradication. Its efficacy for H. pylori eradication has been reported. However, the evidence for its efficacy and feasibility remains limited. We aimed to compare the feasibility, effectiveness and safety of vonoprazan-based triple therapy with conventional proton pump inhibitor (PPI)-based triple therapy in multicenter clinical practice.

METHODS

We performed a multicenter retrospective study on patients receiving first-line H. pylori eradication therapy between March 2013 and November 2015 with either vonoprazan-based triple therapy or conventional PPI-based triple therapy.

RESULTS

A total of 2715 patients aged 63.0 ± 12.1 years (1412 [52.0%] males) were analyzed. Eradication rates were 87.2% (368/422) for vonoprazan-based therapy and 72.4% (1661/2293) for conventional PPI-based therapy (P < 0.01). Among the former group, there were 10 cases of diarrhea, six of nausea/vomiting, and five of rash, but the rates of these adverse events were similar to those in the conventional PPI group.

CONCLUSION

Vonoprazan-based triple therapy is feasible, and has a higher rate for H. pylori eradication than conventional PPI as a first-line regimen.

Histologic intestinal metaplasia and endoscopic atrophy are predictors of gastric cancer development after Helicobacter pylori eradication

BACKGROUND AND AIMS

Helicobacter pylori eradication therapy is effective at reducing the incidence of gastric cancer; however, gastric cancer still develops after eradication. We conducted a cohort study to elucidate the risk factors for gastric cancer development after successful H pylori eradication therapy.

METHODS

From June 1998 to December 2012 we assessed histologic and endoscopic findings of gastritis and performed H pylori eradication therapy in 748 patients without a history of gastric cancer. Patients were classified according to the distribution of intestinal metaplasia (IM) as follows: no IM (IM group A), IM in the antrum only (IM group B), and IM in the corpus (IM group C). We assessed atrophy endoscopically according to the Kimura-Takemoto classification system. Gastric cancer incidence was assessed.

RESULTS

A total of 573 patients underwent follow-up endoscopy; the mean duration of follow-up was 6.2 ± 4.8 years. Gastric cancer developed in 21 (20 intestinal type). The cumulative 5-year incidences of gastric cancer were 3.2% overall; 1.5%, 5.3%, and 9.8% in IM groups A, B, and C; and 0.7%, 1.9%, and 10% in the none/mild, moderate, and severe endoscopic atrophy groups, respectively. Compared with IM group A, the hazard ratio for IM group B was 3.6 (95% confidence interval [CI], 1.2-11), and that for IM group C was 3.7 (95% CI, 1.1-12). Compared with the none/mild endoscopic atrophy group, the hazard ratio for severe atrophy was 9.3 (95% CI, 1.7-174).

CONCLUSIONS

Patients with histologic IM or severe endoscopic atrophy were at increased risk of gastric cancer development after H pylori eradication.

A Pilot Randomized Controlled Study of Dexlansoprazole MR-Based Triple Therapy for Helicobacter Pylori Infection

Dexlansoprazole MR is the R-enantiomer of lansoprazole that is delivered by a dual delayed release formulation. It is effective for symptom control of patients with gastroesophageal reflux disease. However, its efficacy in the treatment of Helicobacter pylori infection remains unclear. This pilot, randomized, controlled, head-to-head study was conducted to investigate whether the efficacy of single-dose dexlansoprazole MR-based triple therapy was noninferior to double-dose rabeprazole-based triple therapy in the treatment of H pylori infection. Consecutive H pylori-infected subjects were randomly allocated to either 7-day dexlansoprazole MR-based standard triple therapy (dexlansoprazole MR 60 mg once daily, clarithromycin 500 mg twice daily, and amoxicillin 1 g twice daily) or rabeprazole-based triple therapy (rabeprazole 20 mg twice daily, clarithromycin 500 mg twice daily, and amoxicillin 1 g twice daily). H pylori status was assessed 6 weeks after the end of treatment. A total of 177 H pylori-infected patients were randomized to receive dexlansoprazole MR-based (n = 90) or rabeprazole-based (n = 87) triple therapy. Intention-to-treat analysis demonstrated no differences between eradication rates of the 2 study groups (83.3% vs 81.6%; P = 0.736). Per-protocol analysis yielded comparable results (85.1% vs 81.2%; P = 0.497). Both groups exhibited similar frequencies of adverse events (7.8% vs 4.6%; P = 0.536) and drug compliance (98.9% vs 97.7%; P = 0.496). Multivariate analysis disclosed that the presence of clarithromycin resistance was the only independent factors predictive of treatment failure with an odds ratio of 6.8 (95% confidence interval: 1.2-37.6). This work demonstrates that single-dose dexlansoprazole MR-based triple therapy yields a similar eradication rate as double-dose rabeprazole-based therapy. Since the pharmaceutical cost of the single-dose dexlansoprazole MR regime is lower than that of the double-dose rabeprazole regimen, dexlansoprazole-based therapy can reasonably be recommended in the first-line treatment of H pylori infection.

Helicobacter pylori Infection Synergistic with IL-1β Gene Polymorphisms Potentially Contributes to the Carcinogenesis of Gastric Cancer

Helicobacter pylori (H. pylori) infection is the most common chronic bacterial infection in the world and the etiological agent for most gastric cancer (GC). Interleukin-1β (IL-1β) is a potent proinflammatory cytokine, and its deregulation is closely associated with the tumorigenesis of several cancers. Recent studies have revealed that the IL-1β-31 and -511T alleles are closely associated with gastric carcinogenesis due to their roles in the induction of gastric precancerous lesions and hypochlorhydria. Furthermore, H. pylori infection has a synergistic effect on the development of GC with IL-1β gene polymorphisms, and the highest prevalence of severe gastric abnormalities are found in patients with both host and bacterial high-risk genotypes (cagA(+)/vacAs1(+)/IL-1β-511T). Therefore, these recent advances demonstrate that H. pylori synergistic with IL-1β gene polymorphisms contribute to the gastric carcinogenesis by their involvement in precancerous gastric lesions and low gastric acid secretion.

Distribution of intestinal metaplasia as a predictor of gastric cancer development

BACKGROUND AND AIM

Helicobacter pylori, gastritis, and intestinal metaplasia (IM) are known risk factors for gastric cancer. In the present study, we conducted a cohort study to evaluate the predictive value of the distribution of IM for gastric cancer development.

METHODS

We conducted a retrospective cohort study at a university hospital. From June 1998 to December 2000, we assessed histological gastritis using biopsy specimens, one from the antrum and one from the corpus, from 1450 patients, among whom 729 revisited for follow-up endoscopy. Patients were classified into three groups according to the distribution of IM at initial endoscopy. IM group A had no IM, IM group B had IM in the antrum only, and IM group C had IM in the corpus. The development of gastric cancer was assessed by endoscopic examination.

RESULTS

The mean duration of follow-up was 6.7 ± 4.7 years. The cumulative incidence of gastric cancer at 5 years was 1.5% in total and 0.8%, 3.3%, and 2.7% in IM groups A, B, and C, respectively. The IM group was identified as an independent risk factor by multivariate analysis; compared with IM group A, hazard ratios were 3.6 (95% confidence interval [CI] 1.1-12.1) in IM group B and 3.8 (95% CI 1.01-14.1) in IM group C. In IM group C, the incidence of gastric cancer in patients who received eradication therapy was significantly lower than that in patients who did not receive (P = 0.021, log-rank).

CONCLUSION

IM is a good predictive marker for the development of gastric cancer.

Helicobacter pylori eradication for the prevention of gastric neoplasia

BACKGROUND

Gastric cancer is the third most common cause of cancer death worldwide. Individuals infected with Helicobacter pylori have a higher likelihood of developing gastric cancer than individuals who are not infected. Eradication of H. pylori in healthy asymptomatic individuals in the general population may reduce the incidence of gastric cancer, but the magnitude of this effect is unclear.

OBJECTIVES

To assess the effectiveness of eradication of H. pylori in healthy asymptomatic individuals in the general population in reducing the incidence of gastric cancer.

SEARCH METHODS

We identified trials by searching the Cochrane Central Register of Controlled Trials (CENTRAL; 2013, Issue 11), MEDLINE (1946 to December 2013), and EMBASE (1974 to December 2013). We handsearched reference lists from trials selected by electronic searching to identify further relevant trials. We handsearched published abstracts from conference proceedings from the United European Gastroenterology Week (published in Gut) and Digestive Disease Week (published in Gastroenterology) between 2001 and 2013. We contacted members of the Cochrane Upper Gastrointestinal and Pancreatic Diseases Review Group and experts in the field and asked them to provide details of outstanding clinical trials and any relevant unpublished materials.

SELECTION CRITERIA

We analysed randomised controlled trials comparing at least one week of H. pylori therapy with placebo or no treatment in preventing subsequent development of gastric cancer in otherwise healthy and asymptomatic H. pylori-positive adults. Trials had to follow up participants for at least two years and needed to have at least two participants with gastric cancer as an outcome. We defined gastric cancer as any gastric adenocarcinoma, including intestinal (differentiated) or diffuse (undifferentiated) type, with or without specified histology.

DATA COLLECTION AND ANALYSIS

We collected data on incidence of gastric cancer, incidence of oesophageal cancer, deaths from gastric cancer, deaths from any cause, and adverse effects arising due to therapy.

MAIN RESULTS

Six trials met all our eligibility criteria and provided extractable data. Three trials were at low risk of bias, one trial was at unclear risk, and two trials were at high risk of bias. Five trials were conducted in Asian populations. In preventing development of subsequent gastric cancer, H. pylori eradication therapy was superior to placebo or no treatment (6 trials, 6497 participants, risk ratio (RR) of developing subsequent gastric cancer 0.66; 95% confidence interval (CI) 0.46 to 0.95; moderate-quality evidence). Only one trial reported effect of eradication of H. pylori on development of subsequent oesophageal cancer (2 (0.2%) among 817 participants assigned to eradication therapy, compared with 1 (0.1%) of 813 participants allocated to placebo; RR 1.99; 95% CI 0.18 to 21.91). The effect of H. pylori eradication on preventing death from gastric cancer compared with placebo or no treatment was uncertain due to wide confidence intervals (3 trials, 4475 participants, RR 0.67; 95% CI 0.40 to 1.11; moderate-quality evidence). There was no evidence of an effect on all-cause mortality (4 trials, 5253 participants, RR 1.09; 95% CI 0.86 to 1.38; moderate-quality evidence). Adverse events data were poorly reported.

AUTHORS' CONCLUSIONS

We found limited, moderate-quality evidence that searching for and eradicating H. pylori reduces the incidence of gastric cancer in healthy asymptomatic infected Asian individuals, but we cannot necessarily extrapolate this data to other populations.

Helicobacter pylori virulence factor CagA promotes tumorigenesis of gastric cancer via multiple signaling pathways

Helicobacter pylori (H. pylori) infection is strongly associated with the development of gastric diseases but also with several extragastric diseases. The clinical outcomes caused by H. pylori infection are considered to be associated with a complex combination of host susceptibility, environmental factors and bacterial isolates. Infections involving H. pylori strains that possess the virulence factor CagA have a worse clinical outcome than those involving CagA-negative strains. It is remarkable that CagA-positive H. pylori increase the risk for gastric cancer over the risk associated with H. pylori infection alone. CagA behaves as a bacterial oncoprotein playing a key role in H. pylori-induced gastric cancer. Activation of oncogenic signaling pathways and inactivation of tumor suppressor pathways are two crucial events in the development of gastric cancer. CagA shows the ability to affect the expression or function of vital protein in oncogenic or tumor suppressor signaling pathways via several molecular mechanisms, such as direct binding or interaction, phosphorylation of vital signaling proteins and methylation of tumor suppressor genes. As a result, CagA continuously dysregulates of these signaling pathways and promotes tumorigenesis. Recent research has enriched our understanding of how CagA effects on these signaling pathways. This review summarizes the results of the most relevant studies, discusses the complex molecular mechanism involved and attempts to delineate the entire signaling pathway.

Helicobacter pylori test-and-treat program can be cost-effective to prevent gastric cancer in Taiwanese adults: referred to the nationwide reimbursement database

BACKGROUND

Helicobacter pylori infection increases the risk of gastric cancer. The study aimed to compare cost-effectiveness ratios of H. pylori test-and-treat programs to prevent gastric cancer in Taiwan, referring to the nationwide reimbursement database and expected years of life lost.

MATERIALS AND METHODS

During 1998-2009, there were 12,857 females and 24,945 males with gastric adenocarcinoma in Taiwan National Cancer Registry. They were followed up to 2010 and linked to the reimbursement database of National Health Insurance and the national mortality registry to determine lifetime health expenditures and expected years of life lost. Cost-effectiveness ratios of H. pylori test-and-treat programs for prevention of gastric adenocarcinoma were compared between screenings with (13) C-urea breath test and with anti-H. pylori IgG.

RESULTS

The test-and-treat program with anti-H. pylori IgG to prevent gastric adenocarcinoma had lower incremental cost-effectiveness ratios than that with (13) C-urea breath test in both sexes (females: 244 vs 1071 US dollars/life-year; males: 312 vs 1431 US dollars/life-year). Cost saving would be achieved in an endemic area where H. pylori prevalence was >73.5%, or by selecting subpopulations with high absolute risk reduction rates of cancer after eradication. Moreover, expected years of life lost of gastric adenocarcinoma were higher and the incremental cost-effectiveness ratios of test-and-treat programs were more cost-effective in young adults (30-69 y/o) than in elders (≥70 y/o).

CONCLUSIONS

The test-and-treat program with anti-H. pylori IgG shall be cost-effective to prevent gastric adenocarcinoma in a high endemic area, especially beginning at 30 years of age when H. pylori prevalence rates become stabilized.

H. pylori and its modulation of gastrointestinal microbiota

The discovery of Helicobacter pylori (H. pylori) changed the dogma of the stomach as a sterile organ. H. pylori is an obligate pathogen in the human stomach and recognized as a definite carcinogen. Extensive research on the interaction of this bacterium with the gastric mucosa has been performed over the past three decades. The development of new nucleotide sequencing techniques and new biocomputational tools has opened the field for studying the diversity and complexity of the microbiome in the gastrointestinal tract independently of cultural methods. These techniques allow to better characterize further gastric bacteria. However, the differentiation of alive resident and transient microbes requires an analysis beyond the pure detection of bacterial genomic material applying a combination with metabolomic analyses. Currently, the interaction of gastric microbiota with each other, with H. pylori and with the host is addressed by extensive research. This review gives a concise overview on current knowledge on this topic.

Reverse sequential therapy achieves a similar eradication rate as standard sequential therapy for Helicobacter pylori eradication: a randomized controlled trial

BACKGROUND AND AIMS

Sequential therapy is a two-step therapy achieving a promising eradication rate for Helicobacter pylori infection. The rationale of sequential method has been proposed that amoxicillin weakens bacterial cell walls in the initial phase of treatment, preventing the development of drug efflux channels for clarithromycin and metronidazole used in the second phase. The aim of this prospective, randomized, controlled study was to investigate whether the efficacy of reverse sequential therapy was noninferior to sequential therapy in the treatment of H. pylori infection.

METHODS

From January 2009 to December 2010, consecutive H. pylori-infected patients were randomly assigned to receive either sequential therapy (a 5-day dual therapy with pantoprazole plus amoxicillin, followed by a 5-day triple therapy with pantoprazole plus clarithromycin and metronidazole) or reverse sequential therapy (a 5-day triple therapy with pantoprazole plus clarithromycin and metronidazole, followed by a 5-day dual therapy with pantoprazole plus amoxicillin). H. pylori status was examined 6 weeks after the end of treatment by rapid urease and histology or urea breath test.

RESULTS

One hundred and twenty-two H. pylori-infected participants were randomized to receive sequential (n = 60) or reverse sequential therapy (n = 62). The eradication rates, by intention-to-treat analysis, were similar: 91.9% (95% confidence interval (CI): 85.1-98.7%) for sequential therapy and 96.7% (95% CI: 92.2-101.2%) for reverse sequential therapy (p = .44). Per-protocol analysis also showed similar results: 91.8% (95% CI: 84.9-98.7%) for sequential group and 96.7% (95% CI: 92.2-101.2%) for reverse sequential therapy (p = .43). The two treatments exhibited comparable frequencies of adverse events (11.3% vs 6.7%, respectively) and drug compliance (98.4% vs 100%, respectively). The overall resistance rates of antibiotics were clarithromycin 10.5%, amoxicillin 0%, and metronidazole 44.2% of patients, respectively. The dual resistance rate of clarithromycin and metronidazole was 4.2%. Both therapies achieved a high eradication rate for clarithromycin-resistant strains (100% vs 100%, respectively) and metronidazole-resistant strains (81.8% vs 95%, respectively) by intention-to-treat analysis.

CONCLUSIONS

Ten-day reverse sequential therapy and standard sequential therapy are equally effective for H. Pylori eradication. The finding indicates that the sequence of antibiotics administered in sequential therapy does not influence the efficacy of the treatment.

Chronic gastritis - an update

Helicobacter pylori is the main aetiologic factor for chronic gastritis worldwide. The degree of inflammation and the evolution of this form of chronic gastritis can vary largely depending on bacterial virulence factors, host susceptibility factors and environmental conditions. Autoimmune gastritis is another cause of chronic inflammation in the stomach, which can occur in all age groups. This disease presents typically with vitamin B12 deficiency and pernicious anaemia. The presence of anti-parietal cell antibodies is highly specific for the diagnosis. The role of H. pylori as a trigger for autoimmune gastritis remains uncertain. Other rare conditions for chronic gastritis are chronic inflammatory conditions such as Crohn's disease or on the background of lymphocytic or collagenous gastroenteropathies.

Randomized controlled trial comparing 7-day triple, 10-day sequential, and 7-day concomitant therapies for Helicobacter pylori infection

With the rising prevalence of antimicrobial resistance, the failure rate of the standard triple therapy for Helicobacter pylori infection is increasing. Sequential therapy and concomitant therapy have been recommended to replace standard triple therapy for H. pylori eradication in regions with high clarithromycin resistance. The aim of this prospective, randomized, and controlled study was to simultaneously assess the efficacies of 10-day sequential and 7-day concomitant therapies versus a 7-day standard triple therapy for treating H. pylori infection. Consecutive H. pylori-infected subjects were randomly assigned to a 7-day standard triple therapy (pantoprazole, clarithromycin, and amoxicillin for 7 days), a 10-day sequential therapy (pantoprazole and amoxicillin for 5 days, followed by pantoprazole, clarithromycin, and metronidazole for a further 5 days), or a 7-day quadruple therapy (pantoprazole, clarithromycin, amoxicillin, and metronidazole for 7 days). H. pylori status was confirmed 6 weeks after therapy. Three hundred seven H. pylori-infected participants were randomized to receive triple (n = 103), sequential (n = 102), or concomitant (n = 102) therapies. The eradication rates by an intention-to-treat analysis in the three treatment groups were 81.6% (95% confidence interval [CI], 74.1% to 89.0%), 89.2% (95% CI, 83.2% to 95.2%), and 94.1% (95% CI, 89.5% to 98.7%). The seven-day concomitant therapy had a higher eradication rate than did the 7-day triple therapy (difference, 12.5%; 95% CI, 3.7% to 21.3%). There were no significant differences in the eradication rates between the sequential and standard triple therapies. All three treatments exhibited similar frequencies of adverse events (8.7%, 8.8%, and 13.7%, respectively) and drug compliance (99.0%, 98.0%, and 100.0%, respectively). In conclusion, the seven-day concomitant therapy is superior to the 7-day standard triple therapy for H. pylori eradication. Additionally, it is less complex than the 10-day sequential therapy because the drugs are not changed halfway through the treatment course. (This study has been registered at ClinicalTrials.gov under registration no. NCT1769365.).

Gastric cancer mortality in a high incidence area: long-term follow-up of Helicobacter pylori-related precancerous lesions in the general population

BACKGROUND

Due to a lack of clear criteria for recognizing subjects at risk of progression to gastric cancer (GC), this cohort study seeks to identify predictors of GC death in a high-risk population.

METHODS

During 2000-2001, 1011 randomly selected residents of Ardabil, Iran without a history of gastrointestinal diseases, underwent upper endoscopy with targeted biopsy sampling. Until 2013, cancer mortality data were obtained using cancer and death registry data and verbal autopsy reports. Cox regression was used to estimate hazard ratios (HR).

RESULTS

A total of 3.95% of the participants [mean age: 53.1 ± 9.9 years, 49.8% males, and 88.2% Helicobacter pylori (H. pylori-positive)] died of GC. In the multivariate model, precancerous lesions at the beginning of follow-up were associated with increased GC mortality. The HR [95% confidence interval (CI)] was 7.4 (1.6-33.8) for atrophic gastritis (AG) and 23.6 (5.5-102.3) for intestinal metaplasia (IM). Age over 50 (HR = 4.4; 1.3-14.2), family history of GC (HR = 6.8; 3.3-13.8), smoking (HR = 7.4; 3.2-17.3), and endoscopically confirmed gastric ulcer (GU, HR = 6.5; 2.5-16.4) were independently associated with GC mortality. The concomitant presence of a precancerous lesion increased the HR to 46.5 (10.8-198.6) for a family history of GC, 27.6 (6.5-116.4) for smoking, and 25.1 (6.3-105.3) for age >50 years.

CONCLUSIONS

In this population with a high rate of H. pylori infection, age over 50 years, smoking, family history of GC, IM, AG, and in particular, an undiagnosed GU were significant independent risk factors for mortality due to GC. The assessment of a combination of these risk factors might identify individuals at risk of GC who could possibly benefit from regular surveillance.

Helicobacter pylori eradication therapy to prevent gastric cancer in healthy asymptomatic infected individuals: systematic review and meta-analysis of randomised controlled trials

OBJECTIVES

To determine whether searching for Helicobacter pylori and treating with eradication therapy leads to a reduction in incidence of gastric cancer among healthy asymptomatic infected individuals.

DESIGN

Systematic review and meta-analysis of randomised controlled trials.

DATA SOURCES

Medline, Embase, and the Cochrane central register of controlled trials were searched through to December 2013. Conference proceedings between 2001 and 2013 were hand searched. A recursive search was performed with bibliographies of relevant studies. There were no language restrictions.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Randomised controlled trials examining the effect of at least seven days of eradication therapy on subsequent occurrence of gastric cancer in adults who tested positive for Helicobacter pylori but otherwise healthy and asymptomatic were eligible. The control arm had to receive placebo or no treatment. Subjects had to be followed for ≥ 2 years.

MAIN OUTCOME MEASURES

Primary outcome, defined a priori, was the effect of eradication therapy on the subsequent occurrence of gastric cancer expressed as a relative risk of gastric cancer with 95% confidence intervals.

RESULTS

The search strategy identified 1560 citations, of which six individual randomised controlled trials were eligible. Fifty one (1.6%) gastric cancers occurred among 3294 individuals who received eradication therapy versus 76 (2.4%) in 3203 control subjects (relative risk 0.66, 95% confidence interval 0.46 to 0.95), with no heterogeneity between studies (I(2)=0%, P=0.60). If the benefit of eradication therapy was assumed to persist lifelong the number needed to treat was as low as 15 for Chinese men and as high as 245 for US women.

CONCLUSIONS

These data provide limited, moderate quality evidence that searching for and eradicating H pylori reduces the incidence of gastric cancer in healthy asymptomatic infected Asian individuals, but these data cannot necessarily be extrapolated to other populations.