Helicobacter pylori infection induces gastric cancer in mongolian gerbils

Characterization of progressive metaplasia in the gastric corpus mucosa of Mongolian gerbils infected with Helicobacter pylori

Spasmolytic polypeptide-expressing metaplasia (SPEM) and intestinal metaplasia are considered neoplastic precursors of gastric adenocarcinoma in humans. Loss of parietal cells causes the development of SPEM in the gastric corpus and then chronic inflammation drives SPEM toward a more proliferative lineage. Mongolian gerbils infected with Helicobacter pylori develop chronic gastritis and metaplasia, mimicking aspects of human gastritis with H. pylori infection. We therefore examined metaplastic lineages in the gastric corpus mucosa of gerbils infected by H. pylori strain 7.13, which produces rapid onset of severe inflammation. Six weeks following H. pylori infection, Griffonia simplicifolia lectin II (GSII)-positive SPEM developed in the base of oxyntic glands in association with parietal cell loss and inflammation. In association with severe inflammation, SPEM glands evolved into aberrant phenotypes, including branched lesions, dilated lesions, and penetrating invasive glands. Mucin 4 (MUC4) was up-regulated in SPEM and progressive SPEM. Clusterin was expressed in the tips of branched and dilated lesions and throughout regions of invasive glands. Intriguingly, clusterin-positive regions in these lesions expressed Ki67 and matrix metalloproteinase 7 (MMP-7). These same regions were also positive for expression of phospho-IkBα, suggestive of activated NFkB signalling. These findings suggest that clusterin-positive regions in progressive phenotypes of SPEM have invasive characteristics. Thus, H. pylori infection in gerbils induces SPEM, which then can progress to further aberrant and invasive metaplastic phenotypes. Copyright © 2016 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Ndrg2 promoter hypermethylation triggered by helicobacter pylori infection correlates with poor patients survival in human gastric carcinoma

N-myc downstream regulated gene 2 (Ndrg2) is a candidate suppressor of cancer metastasis. We found that Ndrg2 promoter was frequently hypermethylated in gastric cancer cell lines and in 292 gastric tumor tissues. This resulted in down-regulation of Ndrg2 mRNA and protein. Ndrg2 promoter methylation was associated with H. pylori infection and worse prognosis of gastric cancer patients, which is an independent prognostic factor for the disease-free survival (DFS). We found that H. pylori silenced Ndrg2 by activating the NF-κB pathway and up-regulating DNMT3b, promoting gastric cancer progression. These findings uncover a previously unrecognized role for H. pylori infection in gastric cancer.

Genetic Diversity as Consequence of a Microaerobic and Neutrophilic Lifestyle

As a neutrophilic bacterium, Helicobacter pylori is growth deficient under extreme acidic conditions. The gastric pathogen is equipped with an acid survival kit, regulating urease activity by a pH-gated urea channel, opening below pH 6.5. After overcoming acid stress, the bacterium’s multiplication site is situated at the gastric mucosa with near neutral pH. The pathogen exhibits exceptional genetic variability, mainly due to its capability of natural transformation, termed competence. Using single cell analysis, we show here that competence is highly regulated in H. pylori. DNA uptake complex activity was reversibly shut down below pH 6.5. pH values above 6.5 opened a competence window, in which competence development was triggered by the combination of pH increase and oxidative stress. In contrast, addition of sublethal concentrations of the DNA-damaging agents ciprofloxacin or mitomycin C did not trigger competence development under our conditions. An oxygen-sensitive mutant lacking superoxide dismutase (sodB) displayed a higher competent fraction of cells than the wild type under comparable conditions. In addition, the sodB mutant was dependent on adenine for growth in broth and turned into non-cultivable coccoid forms in its absence, indicating that adenine had radical quenching capacity. Quantification of periplasmically located DNA in competent wild type cells revealed outstanding median imported DNA amounts of around 350 kb per cell within 10 min of import, with maximally a chromosomal equivalent (1.6 Mb) in individual cells, far exceeding previous amounts detected in other Gram-negative bacteria. We conclude that the pathogen’s high genetic diversity is a consequence of its enormous DNA uptake capacity, triggered by intrinsic and extrinsic oxidative stress once a neutral pH at the site of chronic host colonization allows competence development.

Natural transformation, i.e. the capacity to take up DNA from the environment, is one of the crucial means for horizontal gene transfer and genetic diversity in bacteria. The human gastric pathogen Helicobacter pylori is confronted with acid stress before entering its multiplication site, the gastric mucosa. The bacterium causes lifelong chronic gastritis and is perfectly adapted to the human host, crucially by displaying unusual genetic diversity. Using a single cell approach and well-controlled conditions, we show here that the amount of imported DNA in competent H. pylori is outstanding, far exceeding previous measurement with other Gram-negative bacteria. Furthermore, DNA uptake activity was tightly regulated and limited to pH above 6.5, conditions thought to be met in close contact with the gastric mucosa. In addition, we show that within this pH competence window, competence development was triggered by an increase in pH in combination with the level of oxidative stress. Our data provide explanations for the extraordinary high genetic diversity, often referred to as genome plasticity of this unusual microaerobic pathogen.

Distinct Clinic-Pathological Features of Early Differentiated-Type Gastric Cancers after Helicobacter pylori Eradication

Background. Gastric cancer is discovered even after successful eradication of H. pylori. We investigated clinic pathological features of early gastric cancers after H. pylori eradication. Methods. 51 early gastric cancers (EGCs) from 44 patients diagnosed after successful H. pylori eradication were included as eradication group. The clinic-pathological features were compared with that of 131 EGCs from 120 patients who did not have a history of H. pylori eradication (control group). Results. Compared with control group, clinic-pathological features of eradication group were characterized as depressed (p < 0.0001), reddish (p = 0.0001), and smaller (p = 0.0095) lesions, which was also confirmed in the comparison of six metachronous lesions diagnosed after initial ESD and subsequent successful H. pylori eradication. Prevalence of both SM2 (submucosal invasion greater than 500 μm) and unexpected SM2 cases tended to be higher in eradication group (p = 0.077, 0.0867, resp.). Prevalence of inconclusive diagnosis of gastric cancer during pretreatment biopsy was also higher in the same group (26.0% versus 1.6%, p < 0.0001). Conclusions. Informative clinic pathological features of EGC after H. pylori eradication are depressed, reddish appearances, which should be treated as a caution because histological diagnosis of cancerous tissue is sometimes difficult by endoscopic biopsy.

Rapid Fiber-optic Raman Spectroscopy for Real-Time In Vivo Detection of Gastric Intestinal Metaplasia during Clinical Gastroscopy

We report a unique simultaneous fingerprint (FP) and high-wavenumber (HW) Raman spectroscopy technique coupled with a beveled fiber-optic Raman probe for improving in vivo detection of gastric intestinal metaplasia (IM)-precancerous lesions in real-time during clinical gastroscopy. A total of 4,520 high-quality in vivo FP/HW gastric Raman spectra (normal = 4,178; IM = 342) were acquired from 157 gastric patients undergoing endoscopic examination. Multivariate diagnostic algorithms based on principal components analysis and linear discriminant analysis together with the leave-one tissue site-out, cross-validation on in vivo tissue Raman spectra yield the diagnostic sensitivities of 89.3%, 89.3%, and 75.0%; specificities of 92.2%, 84.4%, and 82.0%; positive predictive values of 52.1%, 35.2%, and 28.4%; and negative predictive values of 98.9%, 98.8%, and 97.2%, respectively, by using the integrated FP/HW, FP, and HW Raman techniques for identifying IM from normal gastric tissue. Further, ROC curves generated show that the integrated FP/HW Raman technique gives the integration area under the ROC curve of 0.92 for IM classification, which is superior to either FP (0.89) or HW Raman (0.86) technique alone. This work demonstrates for the first time that the simultaneous FP/HW fiber-optic Raman spectroscopy has great potential to enhance early diagnosis of gastric precancer in vivo during routine endoscopic examination. Cancer Prev Res; 9(6); 476-83. ©2016 AACR.

Role of Helicobacter pylori in gastric cancer: Updates

Helicobacter pylori (H. pylori) infection is highly prevalent in human, affecting nearly half of the world’s population; however, infection remains asymptomatic in majority of population. During its co-existence with humans, H. pylori has evolved various strategies to maintain a mild gastritis and limit the immune response of host. On the other side, presence of H. pylori is also associated with increased risk for the development of various gastric pathologies including gastric cancer (GC). A complex combination of host genetics, environmental agents, and bacterial virulence factors are considered to determine the susceptibility as well as the severity of outcome in a subset of individuals. GC is one of the most common cancers and considered as the third most common cause of cancer related death worldwide. Many studies had proved H. pylori as an important risk factor in the development of non-cardia GC. Although both H. pylori infection and GC are showing decreasing trends in the developed world, they still remain a major threat to human population in the developing countries. The current review attempts to highlight recent progress in the field of research on H. pylori induced GC and aims to provide brief insight into H. pylori pathogenesis, the role of major virulence factors of H. pylori that modulates the host environment and transform the normal gastric epithelium to neoplastic one. This review also emphasizes on the mechanistic understanding of how colonization and various virulence attributes of H. pylori as well as the host innate and adaptive immune responses modulate the diverse signaling pathways that leads to different disease outcomes including GC.

Expression of cagA, virB/D Complex and/or vacA Genes in Helicobacter pylori Strains Originating from Patients with Gastric Diseases

In order to better understand pathogenicity of Helicobacter pylori, particularly in the context of its carcinogenic activity, we analysed expression of virulence genes: cagA, virB/D complex (virB4, virB7, virB8, virB9, virB10, virB11, virD4) and vacA in strains of the pathogen originating from persons with gastric diseases. The studies were conducted on 42 strains of H. pylori isolated from patients with histological diagnosis of non-atrophic gastritis—NAG (group 1, including subgroup 1 containing cagA⁺ isolates and subgroup 2 containing cagA^- strains), multifocal atrophic gastritis—MAG (group 2) and gastric adenocarcinoma—GC (group 3). Expression of H. pylori genes was studied using microarray technology. In group 1, in all strains of H. pylori cagA⁺ (subgroup 1) high expression of the gene as well as of virB/D was disclosed, accompanied by moderate expression of vacA. In strains of subgroup 2 a moderate expression of vacA was detected. All strains in groups 2 and 3 carried cagA gene but they differed in its expression: a high expression was detected in isolates of group 2 and its hyperexpression in strains of group 3 (hypervirulent strains). In both groups high expression of virB/D and vacA was disclosed. Our results indicate that chronic active gastritis may be induced by both cagA⁺ strains of H. pylori, manifesting high expression of virB/D complex but moderate activity of vacA, and cagA^- strains with moderate expression of vacA gene. On the other hand, in progression of gastric pathology and carcinogenesis linked to H. pylori a significant role was played by hypervirulent strains, manifesting a very high expression of cagA and high activity of virB/D and vacA genes.

Dietary Intervention of Artemisia and Green Tea Extracts to Rejuvenate Helicobacter pylori-Associated Chronic Atrophic Gastritis and to Prevent Tumorigenesis

OBJECT

As nonmicrobial dietary approach is capable of controlling Helicobacter pylori infection, we evaluated the efficacy of long-term dietary administration of Artemisia and/or green tea extracts on H. pylori-initiated, high-salt-promoted chronic atrophic gastritis and gastric tumorigenesis mouse model.

METHODS

Helicobacter pylori-infected and high-salt-diet-administered C57BL/6 mice were administered with Artemisia extracts (MP group) and/or green tea extracts (GT group) for 36 weeks in addition to the control group (ES group, gastroprotective drug, ecabet sodium 30 mg/kg, diet pellet). Gross and pathological gastric lesions were evaluated after 24 and 36 weeks, respectively, and their underlying molecular changes were measured in gastric homogenates. Detailed mechanisms were further evaluated in in vitro cell models.

RESULTS

The erythematous and nodular changes and mucosal ulcerative and erosive lesions were noted in the control group at 24 weeks. MP, GT, MPGT, and ES groups all showed significantly ameliorated pathologic lesion compared to the control group (p < .05). After the 36 weeks, scattered nodular masses with some central ulcers and thin gastric surface were noted in the control stomach, whereas no tumorous lesion and milder atrophic changes were observed in all MP, GT, and MPGT groups except ES group (p < .05). On molecular analysis, increased expressions of COX-2, TNF-α, IL-6, lipid peroxide, and activated STAT3 relevant to H. pylori infection were significantly decreased with MPGT administration (p < .01), whereas HSP70 was significantly increased. PGDH expressions, core tumor suppressor involved in carcinogenesis, were significantly decreased with H. pylori infection (p < .05), but significantly increased in MPGT group (p < .05). Increased mucosal apoptotic index noted in the control group was significantly decreased with MP and/or GT along with significantly preserved gastric gastroprotective mediators (p < .01) such as mucins, HSP27, and HSP70. H. pylori-induced serum TNF-α and NF-κB activations were significantly decreased with MPGT administration (p < .05).

CONCLUSION

Long-term dietary intake of MP and/or GT can be an effective strategy either to rejuvenate H. pylori atrophic gastritis or to suppress tumorigenesis.

Cloning, expression and purification flagellar sheath adhesion of Helicobacter pylori in Escherichia coli host as a vaccination target

Purpose

Helicobacter pylori is a widely distributed gram-negative bacterium that infects the human stomach and duodenum. HpaA is a H. pylori–specific lipoprotein that has been shown to be an effective protective antigen against H. pylori infection. HpaA of H. pylori as a vaccine antigen is fully competent for stimulation of immune responses. The aim of this project is cloning, expression, and purification flagellar sheath adhesion of H. pylori in Escherichia coli host by fast protein liquid chromatography (FPLC) as a vaccination target.

Materials and Methods

The hpaA gene was inserted into pET28a (+) as cloning and expression vectors respectively. The recombinant plasmid (pET-hpaA) was subjected to sequencing other than polymerase chain reaction (PCR) and digestion analysis. Protein expression was induced by adding 1 mM isopropyl-β-D-thiogalactoside to cultures of E. coli strain BL21 transformed with pET-hpaA. Protein expression assessed with sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) analysis. Protein purification of flagellar sheath adhesion was by FPLC.

Results

The restriction endonuclease digestion, PCR amplification analysis showed that the hpaA gene of 730 bp was amplified from H. pylori DNA and sequencing analysis of the pET-hpaA confirmed the cloning accuracy and in frame insertion of hpaA fragment. SDS-PAGE analysis showed the expression of an approximately 29,000 Da protein.

Conclusion

Sequencing results along with SDS-PAGE analysis confirms the expression of recombinant hpaA in the heterologous E. coli BL21. Conclusion A prokaryotic expression system for hpaA gene was successfully constructed. These results indicate that production of a specific recombinant protein is an alternative and potentially more expeditious strategy for development of H. pylori vaccine.

Helicobacter pylori Diversity and Gastric Cancer Risk

Gastric cancer is a leading cause of cancer-related death worldwide. Helicobacter pylori infection is the strongest known risk factor for this malignancy. An important goal is to identify H. pylori-infected persons at high risk for gastric cancer, so that these individuals can be targeted for therapeutic intervention. H. pylori exhibits a high level of intraspecies genetic diversity, and over the past two decades, many studies have endeavored to identify strain-specific features of H. pylori that are linked to development of gastric cancer. One of the most prominent differences among H. pylori strains is the presence or absence of a 40-kb chromosomal region known as the cag pathogenicity island (PAI). Current evidence suggests that the risk of gastric cancer is very low among persons harboring H. pylori strains that lack the cag PAI. Among persons harboring strains that contain the cag PAI, the risk of gastric cancer is shaped by a complex interplay among multiple strain-specific bacterial factors as well as host factors. This review discusses the strain-specific properties of H. pylori that correlate with increased gastric cancer risk, focusing in particular on secreted proteins and surface-exposed proteins, and describes evidence from cell culture and animal models linking these factors to gastric cancer pathogenesis. Strain-specific features of H. pylori that may account for geographic variation in gastric cancer incidence are also discussed.

Association of Hay Fever with the Failure of Helicobacter pylori Primary Eradication

Objective Recently, the number of patients receiving Helicobacter pylori eradication treatment has dramatically increased in Japan, although the eradication rate has gradually decreased. Patient characteristics could affect the eradication rate. Our aim in this study was to investigate the association between failed first-line eradication therapy and hay fever. Methods We researched 356 patients who visited a pharmacy adjacent to the Internal Medicine clinic with a prescription for first-line H. pylori eradication treatment and investigated whether the patients had hay fever using a questionnaire. We separated these patients into 2 groups based on the success or failure of eradication according to the clinical data and performed a logistic regression analysis to investigate the influence of hay fever on first-line eradication failure. Results The eradication rate of patients with and without hay fever was 65.6% and 77.7%, respectively. The adjusted odds ratios according to which patients with hay fever would fail eradication therapy gradually lowered with increasing patient age [≤50 years, odds ratio (OR) 6.81, p=0.089; 51-60 years, OR 2.75, p=0.145; 61-70 years, OR 1.60, p=0.391; >70 years, OR 1.02, p=0.979]. A significant relationship was found for all patients (OR 1.88, p=0.047) and the age group ≤70 years (OR 2.31, p=0.024). Conclusion Patients with hay fever have difficulty with first-line eradication, especially younger patients. The existence of clarithromycin-resistant bacteria is suspected, and other factors may also be involved. When a hay fever sufferer receives first-line treatment, eradication might be difficult and other treatment may be required.

[Unpleasant Journey from Helicobacter pylori-associated Gastritis to Gastric Cancer: Cancer Prevention by Taking a Detour]

As a commensal or a pathogen, Helicobacter pylori can change the balance of a complex interaction that exists among gastric epithelial cells, microbes, and their environment. Therefore, unraveling this complex relationship of these mixtures can be expected to help prevent cancer as well as troublesome unmet medical needs of H. pylori infection. Though gastric carcinogenesis is a multi-step process, precancerous lesion can be reversible in the early phase of mucosal damage before reaching the stage of no return. However, biomarkers to predict rejuvenation of precancerous atrophic gastritis have not been identified yet and gastric cancer prevention is still regarded as an impregnable fortress. However, when we take the journey from H. pylori-associated gastritis to gastric cancer, it provides us with the clue for prevention since there are two main preventive strategies: eradication and anti-inflammation. The evidence supporting the former strategy is now ongoing in Japan through a nation-wide effort to eradicate H. pylori in patients with chronic gastritis, but suboptimal apprehension to increasing H. pylori resistance to antibiotics and patient non-compliance still exists. The latter strategy has been continued in the author'sresearch center under siTRP (short-term intervention to revert premalignant lesion) strategy. By focusing on the role of inflammation in the development of H. pylori-associated gastric carcinogenesis, this review is intended to explain the connection between inflammation and gastric cancer. Strategies on H. pylori eradication, removal of inflammation, and reverting preneoplastic lesion will also be introduced. In the end, we expect to be able to prevent gastric cancer by take a detour from the unpleasant journey, i.e. from H. pylori-associated gastritis to gastric cancer.

Proton pump inhibitors and helicobacter pylori-associated pathogenesis

The fact that long-term use of proton pump inhibitors (PPIs) aggravates corpus atrophic gastritis in patients with Helicobacter pylori infection has been proven clinically and experimentally. Corpus atrophic gastritis is a known risk factor for gastric cancer. Therefore, gastric neoplasia might be associated with the long-term use of PPIs. One of the causes of worsening corpus atrophic gastritis, leading to the development of adenocarcinoma, might be bacterial overgrowth under conditions of hypochlorhydria. The production of potentially carcinogenic N-nitrosocompounds by nitrosating organisms under conditions of hypochlorhydria might be associated with carcinogenesis. Interactions between bile acids, pH, and H. pylori might also contribute to carcinogenicity, especially in patients with gastro-esophageal reflux disease (GERD). The concentration of soluble bile acids, which have bactericidal or chemorepellent properties toward H. pylori, in gastric contents is considerably higher in patients undergoing continuous PPI therapy than in healthy individuals with normal acid production. Under these circumstances, H. pylori might colonize the stomach body rather than the pyloric antrum. Hypergastrinemia induced by PPI administration might promote the development of gastric cancer. Because the main cause of corpus atrophic gastritis is H. pylori infection, and not PPI administration, H. pylori infection should be eradicated before starting long-term PPI therapy.

Gastric Metaplasia Induced by Helicobacter pylori Is Associated with Enhanced SOX9 Expression via Interleukin-1 Signaling

Histopathological changes of the gastric mucosa after Helicobacter pylori infection, such as atrophy, metaplasia, and dysplasia, are considered to be precursors of gastric cancer, yet the mechanisms of histological progression are unknown. The aim of this study was to analyze the histopathological features of the gastric mucosa in mice infected with H. pylori strain PMSS1 in relation to gastric stem cell marker expression. C57BL/6J mice infected with PMSS1 were examined for histopathological changes, levels of proinflammatory cytokines, and expression of stem cell markers. Histopathological gastritis scores, such as atrophy and metaplasia, and levels of proinflammatory cytokines, such as tumor necrosis factor alpha (TNF-α) and interleukin-1β (IL-1β), were increased after PMSS1 infection. Expression levels of the cell proliferation and stem cell markers CD44 and SOX9 were also significantly increased in PMSS1-infected mice. Importantly, almost all metaplastic cells induced by PMSS1 infection expressed SOX9. When IL-1 receptor (IL-1R) knockout mice were infected with PMSS1, metaplastic changes and expression levels of stem cell markers were significantly decreased compared with those in wild-type (WT) mice. In conclusion, H. pylori infection induced the expression of cytokines and stem cell markers and histopathological metaplasia in the mouse gastric mucosa. SOX9 expression, in particular, was strongly associated with metaplastic changes, and these changes were dependent on IL-1 signaling. The results suggested the importance of SOX9 in gastric carcinogenesis.

Treatment outcomes and survival study of gastric cancer patients: a retrospective analysis in an endemic region

PURPOSE

To present information about prognostic factors of gastric cancer patients treated in our Erzurum center including age, gender, tumour location, pathological grade, stage and the effect of treatment on survival.

MATERIALS AND METHODS

This retrospective study was performed on patients who applied to our clinic and diagnosed as gastric cancer. Age and gender of the patients, primary location, histopathological characteristics, TNM stage of the gastric cancers (GCs), treatment applied, oncological treatment modalities and survival outcomes were studied. A univariate analysis of potential prognostic factors was performed with the log-rank test for categorical factors and parameters with a p value < 0.05 at the univariate step were included in the multivariate regression.

RESULTS

A total of 228 patients with a confirmed diagnosis of gastric cancer were included in the study with a male/female ratio of 1.47. Median follow-up period was estimated as 22.3 (range, 3 to 96) months. When diagnosis of the patients at admission was analysed, stage III patients were most frequently encountered (n=147; 64.5%). One hundred and twenty-six (55.3%) underwent surgical treatment, while 117 (51.3%) were given adjuvant chemotherapy. Median overall survival time was 18.0 (± 1.19) months. Mean overall survival rates for 1, 2, 3 and 5 years were 68 ± 0.031%, 36 ± 0.033%, 24 ± 0.031% and 15.5 ± 0.036%, respectively. Univariate variables found to be significant for median OS in the multivariate analysis were evaluated with Cox regression analysis. A significant difference was found among TNM stage groups, location of the tumour and postoperative adjuvant treatment receivers (p values were 0.011, 0.025 and 0.001, respectively).

CONCLUSIONS

This study revealed that it is possible to achieve long-term survival of gastric cancer with early diagnosis. Besides, in locally advanced GC patients, curative resection followed by adjuvant concomitant chemoradiotherapy based on the McDonald regimen was an independent prognostic factor for survival.

Helicobacter pylori Might Induce TGF-β1-Mediated EMT by Means of cagE

BACKGROUND

Epithelial-mesenchymal transition (EMT), in which polarized epithelial cells have mesenchymal cell phenotypes, is thought to be a key process of invasion and metastasis of cancer. Transforming growth factor beta-1 (TGF-β1) is known to be carcinogenic and Helicobacter pylori is a predominant carcinogen of gastric cancer. Our study aimed to determine whether TGF-β1 or H. pylori infection enhances EMT process and cytotoxin-associated gene E (CagE) is associated with EMT.

MATERIALS AND METHODS

Human gastric cancer cell AGS and MKN45 were treated with recombinant TGF-β1 or H. pylori including cagE-negative (ΔcagE) mutant. Besides the assessment of EMT-related markers expression levels by means of RT-qPCR, Western blot, and immunofluorescence assay, the induction of in vitro EMT on gastric cancer cells (AGS and MKN cell lines) was confirmed by wound-healing assay and invasion assay.

RESULTS

When gastric cancer cells were treated with TGF-β1 or various strains of cagE-positive H. pylori, EMT-related marker altered significantly. However, the ΔcagE mutant did not. Wound-healing assay and invasion assay showed enhanced migration ability of the cells treated with cagE-positive H. pylori but not in ΔcagE mutant.

CONCLUSIONS

EMT induction in gastric cancer cells by TGF-β1 was confirmed. Only infection with cagE-positive H. pylori upregulated the TGF-β1-mediated EMT pathway and consequently promotes EMT. Therefore, H. pylori might induce TGF-β1-mediated EMT associated with the cagE.

New progress in study of risk factors for gastric cancer

Gastric cancer is one of the most common malignant tumors, and its etiology is not clear yet. Numerous studies show that the development of gastric cancer is a complex process related with many factors, such as demographic, lifestyle and diet, infectious, hereditary, socioeconomic, and mental factors. Early prevention can effectively reduce the incidence of gastric cancer. Here we make a review of the new progress in research of risk factors for gastric cancer.

The Metabonomic Studies of Tongue Coating in H. pylori Positive Chronic Gastritis Patients

In Traditional Chinese Medicine (TCM), tongue diagnosis (TD) has been an important diagnostic method for the last 3000 years. Tongue coating can be used as a very sensitive marker to determine the progress of chronic gastritis. Therefore, the scientific, qualitative, and quantitative study for the pathophysiologic basis of tongue coating (TC) emerged as a major direction for the objective research of TD. In our current report, we used GC/MS technology to determine the potential changes of metabolites and identify special metabolic biomarkers in the TC of H. pylori infected chronic gastritis patients. Four discriminative metabolites were identified by GC/MS between the TC of H. pylori infection (G + H) and without H. pylori infection (G - H) patients: ethylene, cephaloridine, γ-aminobutyric acid, and 5-pyroglutamic acid, indicating that changes in amino acid metabolism are possibly involved in the formation of TC, and the amino acid metabolites are part of the material components of TC in G + H patients.

Glycosylation-Based Serum Biomarkers for Cancer Diagnostics and Prognostics

Cancer is the second most common cause of death in developed countries with approximately 14 million newly diagnosed individuals and over 6 million cancer-related deaths in 2012. Many cancers are discovered at a more advanced stage but better survival rates are correlated with earlier detection. Current clinically approved cancer biomarkers are most effective when applied to patients with widespread cancer. Single biomarkers with satisfactory sensitivity and specificity have not been identified for the most common cancers and some biomarkers are ineffective for the detection of early stage cancers. Thus, novel biomarkers with better diagnostic and prognostic performance are required. Aberrant protein glycosylation is well known hallmark of cancer and represents a promising source of potential biomarkers. Glycoproteins enter circulation from tissues or blood cells through active secretion or leakage and patient serum is an attractive option as a source for biomarkers from a clinical and diagnostic perspective. A plethora of technical approaches have been developed to address the challenges of glycosylation structure detection and determination. This review summarises currently utilised glycoprotein biomarkers and novel glycosylation-based biomarkers from the serum glycoproteome under investigation as cancer diagnostics and for monitoring and prognostics and includes details of recent high throughput and other emerging glycoanalytical techniques.

Omega-3 Polyunsaturated Fatty Acids Intake to Regulate Helicobacter pylori-Associated Gastric Diseases as Nonantimicrobial Dietary Approach

Omega-3 polyunsaturated fatty acids (n-3 PUFAs), commonly eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), have been acknowledged as essential long-chain fatty acids imposing either optimal health promotion or the rescuing from chronic inflammatory diseases such as atherosclerosis, fatty liver, and various inflammatory gastrointestinal diseases. Recent studies dealing with EPA and DHA have sparked highest interests because detailed molecular mechanisms had been documented with the identification of its receptor, G protein coupled receptor, and GPR120. In this review article, we have described clear evidences showing that n-3 PUFAs could reduce various Helicobacter pylori- (H. pylori-) associated gastric diseases and extended to play even cancer preventive outcomes including H. pylori-associated gastric cancer by influencing multiple targets, including proliferation, survival, angiogenesis, inflammation, and metastasis. Since our previous studies strongly concluded that nonantimicrobial dietary approach for reducing inflammation, for instance, application of phytoceuticals, probiotics, natural products including Korean red ginseng, and walnut plentiful of n-3 PUFAs, might be prerequisite step for preventing H. pylori-associated gastric cancer as well as facilitating the rejuvenation of precancerous atrophic gastritis, these beneficial lipids can restore or modify inflammation-associated lipid distortion and correction of altered lipid rafts to send right signaling to maintain healthy stomach even after chronic H. pylori infection.

An association study of histological types of gastric carcinoma with Helicobacter pylori infection

The aim of this study was to study the relation between histopathological classification of gastric carcinoma and Helicobacter pylori (H. pylori) infection. 200 patients with confirmed gastric carcinoma between January 2010 and January 2012 from our hospital were included. All these patients went through endoscopy and histological examinations for gastric carcinoma and immunological test for H. pylori infection. Patients were grouped according to the histological classification, and the infection rates of H. pylori in different groups were compared. Types of gastric cancer that was closely related to H. pylori infection were identified. Infection rate in patients with the intestinal type of gastric cancer was significantly higher compared to those with the diffuse type. For tubular type of carcinoma, the well to medium-differentiated group had a significantly higher infection rate than the poorly differentiated group. Helicobacter pylori infection and histological types were relevant. The effect of H. pylori infection on the intestinal type was more significant than that on the diffuse type. The infection rate of well-differentiated group was higher than that of the poorly differentiated group, which suggested an association between H. pylori infection and the degree of differentiation of tubular cancerous tissue.

Increased Helicobacter pylori-associated gastric cancer risk in the Andean region of Colombia is mediated by spermine oxidase

Helicobacter pylori infection causes gastric cancer, the third leading cause of cancer death worldwide. More than half of the world's population is infected, making universal eradication impractical. Clinical trials suggest that antibiotic treatment only reduces gastric cancer risk in patients with non-atrophic gastritis (NAG), and is ineffective once preneoplastic lesions of multifocal atrophic gastritis (MAG) and intestinal metaplasia (IM) have occurred. Therefore, additional strategies for risk stratification and chemoprevention of gastric cancer are needed. We have implicated polyamines, generated by the rate-limiting enzyme ornithine decarboxylase (ODC), in gastric carcinogenesis. During H. pylori infection, the enzyme spermine oxidase (SMOX) is induced, which generates hydrogen peroxide from the catabolism of the polyamine spermine. Herein, we assessed the role of SMOX in the increased gastric cancer risk in Colombia associated with the Andean mountain region when compared with the low-risk region on the Pacific coast. When cocultured with gastric epithelial cells, clinical strains of H. pylori from the high-risk region induced more SMOX expression and oxidative DNA damage, and less apoptosis than low-risk strains. These findings were not attributable to differences in the cytotoxin-associated gene A oncoprotein. Gastric tissues from subjects from the high-risk region exhibited greater levels of SMOX and oxidative DNA damage by immunohistochemistry and flow cytometry, and this occurred in NAG, MAG and IM. In Mongolian gerbils, a prototype colonizing strain from the high-risk region induced more SMOX, DNA damage, dysplasia and adenocarcinoma than a colonizing strain from the low-risk region. Treatment of gerbils with either α-difluoromethylornithine, an inhibitor of ODC, or MDL 72527 (N(1),N(4)-Di(buta-2,3-dien-1-yl)butane-1,4-diamine dihydrochloride), an inhibitor of SMOX, reduced gastric dysplasia and carcinoma, as well as apoptosis-resistant cells with DNA damage. These data indicate that aberrant activation of polyamine-driven oxidative stress is a marker of gastric cancer risk and a target for chemoprevention.

Gastrin May Mediate the Carcinogenic Effect of Helicobacter pylori Infection of the Stomach

Gastric cancer occurs almost exclusively in patients with gastritis. Since Helicobacter pylori (Hp) was proved to cause gastritis, Hp was also expected to play a role in gastric carcinogenesis. Despite extensive studies, the mechanisms by which Hp cause gastric cancer are still poorly understood. However, there is evidence that the anatomical site of Hp infection is of major importance. Infection confined to the antral mucosa protects against gastric cancer but predisposes to duodenal ulcer, whereas Hp infection of the oxyntic mucosa increases the risk of gastric cancer. Hp infection does not predispose to cancers in the gastric cardia. In patients with atrophic gastritis of the oxyntic mucosa, the intragastric pH is elevated and the concentration of microorganisms in the stomach is increased. This does not lead to increased risk of gastric cancer at all anatomical sites. The site specificity of Hp infection in relation to cancer risk indicates that neither Hp nor the changes in gastric microflora due to gastric hypoacidity are carcinogenic per se. However, reduced gastric acidity also leads to hypergastrinemia, which stimulates the function and proliferation of enterochromaffin-like (ECL) cells located in the oxyntic mucosa. The ECL cell may be more important in human gastric carcinogenesis than previously realized, as every condition causing long-term hypergastrinemia in animals results in the development of neoplasia in the oxyntic mucosa. Patients with hypergastrinemia will far more often develop carcinomas in the gastric corpus. In conclusion, hypergastrinemia may explain the carcinogenic effect of Hp.

Cancer-promoting effects of microbial dysbiosis

Humans depend on our commensal bacteria for nutritive, immune-modulating, and metabolic contributions to maintenance of health. However, this commensal community exists in careful balance that, if disrupted, enters dysbiosis; this has been shown to contribute to the pathogenesis of colon, gastric, esophageal, pancreatic, laryngeal, breast, and gallbladder carcinomas. This development is closely tied to host inflammation, which causes and is aggravated by microbial dysbiosis and increases vulnerability to pathogens. Advances in sequencing technology have increased our ability to catalog microbial species associated with various cancer types across the body. However, defining microbial biomarkers as cancer predictors presents multiple challenges, and existing studies identifying cancer-associated bacteria have reported inconsistent outcomes. Combining metabolites and microbiome analyses can help elucidate interactions between gut microbiota, metabolism, and the host. Ultimately, understanding how gut dysbiosis impacts host response and inflammation will be critical to creating an accurate picture of the role of the microbiome in cancer.

Rebamipide improves chronic inflammation in the lesser curvature of the corpus after Helicobacter pylori eradication: a multicenter study

Background and Aim. Although many epidemiologic studies have shown that Helicobacter pylori eradication has prophylactic effects on gastric cancer, it does not completely eliminate the risk of gastric cancer. We aimed to investigate the changes in histological gastritis in patients receiving rebamipide treatment after H. pylori eradication. Methods. 206 patients who had undergone H. pylori eradication were evaluated. Of these, 169 patients who achieved successful eradication were randomly allocated to 2 groups: the rebamipide group (n = 82) and the untreated group (n = 87). The primary endpoints were histopathological findings according to the updated Sydney system at the start of the study and after 1 year. Results. Final assessment for histological gastritis was possible in 50 cases from the rebamipide group and 53 cases from the untreated group. The activity and atrophy improved in both the rebamipide and untreated groups, and no significant intergroup differences were observed. Chronic inflammation affecting the lesser curvature of the corpus was significantly improved in the rebamipide group compared to in the untreated group (1.12 ± 0.08 versus 1.35 ± 0.08; P = 0.043). Conclusions. Rebamipide treatment after H. pylori eradication alleviated chronic inflammation in the lesser curvature of the corpus compared to that in the untreated group. This trial is registered with UMIN000002369.

CD44 plays a functional role in Helicobacter pylori-induced epithelial cell proliferation

The cytotoxin-associated gene (Cag) pathogenicity island is a strain-specific constituent of Helicobacter pylori (H. pylori) that augments cancer risk. CagA translocates into the cytoplasm where it stimulates cell signaling through the interaction with tyrosine kinase c-Met receptor, leading cellular proliferation. Identified as a potential gastric stem cell marker, cluster-of-differentiation (CD) CD44 also acts as a co-receptor for c-Met, but whether it plays a functional role in H. pylori-induced epithelial proliferation is unknown. We tested the hypothesis that CD44 plays a functional role in H. pylori-induced epithelial cell proliferation. To assay changes in gastric epithelial cell proliferation in relation to the direct interaction with H. pylori, human- and mouse-derived gastric organoids were infected with the G27 H. pylori strain or a mutant G27 strain bearing cagA deletion (∆CagA::cat). Epithelial proliferation was quantified by EdU immunostaining. Phosphorylation of c-Met was analyzed by immunoprecipitation followed by Western blot analysis for expression of CD44 and CagA. H. pylori infection of both mouse- and human-derived gastric organoids induced epithelial proliferation that correlated with c-Met phosphorylation. CagA and CD44 co-immunoprecipitated with phosphorylated c-Met. The formation of this complex did not occur in organoids infected with ∆CagA::cat. Epithelial proliferation in response to H. pylori infection was lost in infected organoids derived from CD44-deficient mouse stomachs. Human-derived fundic gastric organoids exhibited an induction in proliferation when infected with H. pylori that was not seen in organoids pre-treated with a peptide inhibitor specific to CD44. In the well-established Mongolian gerbil model of gastric cancer, animals treated with CD44 peptide inhibitor Pep1, resulted in the inhibition of H. pylori-induced proliferation and associated atrophic gastritis. The current study reports a unique approach to study H. pylori interaction with the human gastric epithelium. Here, we show that CD44 plays a functional role in H. pylori-induced epithelial cell proliferation.

A tool to predict risk for gastric cancer in patients with peptic ulcer disease on the basis of a nationwide cohort

BACKGROUND & AIMS

Patients with gastric ulcers have significantly higher risk of gastric cancer, especially within 2 years after diagnosis. We used data from a national database to develop a personalized risk prediction model for patients with peptic ulcer diseases.

METHODS

We collected data from Taiwan's National Health Insurance Research Database on 278,898 patients admitted for the first time with a primary diagnosis of peptic ulcer disease. We used the data to develop a nomogram, which we validated by discrimination and calibration, and in a test cohort. Cumulative incidences of study subjects predicted by the nomogram were examined.

RESULTS

In total, 1269 subjects developed gastric cancer. Age, sex, peptic ulcer sites, peptic ulcer complications, Helicobacter pylori eradication, nonsteroidal anti-inflammatory drug use, and surveillance endoscopy were independent factors associated with risk of gastric cancer (all P < .001). The concordance index for the nomogram developed on the basis of these factors was 0.78. Study subjects were divided into quartiles of predicted risk scores; from lowest score quartile to highest, cumulative incidences at 1 year were 7.4/10,000 people, 14.2/10,000 people, 25.5/10,000 people, and 86.6/10,000 people. The cumulative incidences at 2 years were 9.3/10,000 people, 20.9/10,000 people, 38.0/10,000 people, and 135.7/10,000 people for the same quartiles of risk scores. The nomogram was validated in an independent cohort, and similar incidence values were determined.

CONCLUSIONS

We developed and validated a nomogram to predict risk for gastric cancer 1 and 2 years after diagnosis of peptic ulcer disease. The nomogram provides a prognostic tool that can be easily used for individuals and can help physicians explain risk levels to patients.

Effect of Alginate Lyase on Biofilm-GrownHelicobacter pyloriProbed by Atomic Force Microscopy

Helicobacter pylori(H. pylori) is a microorganism with a pronounced capability of adaptation under environmental stress solicitations. Its persistence and antimicrobial resistance to the drugs commonly used in the anti-H. pyloritherapy are associated with the development of a biofilm mainly composed of DNA, proteins, and polysaccharides. A fundamental step to increase the success of clinical treatments is the development of new strategies and molecules able to interfere with the biofilm architecture and thus able to enhance the effects of antibiotics. By using Atomic Force Microscopy and Scanning Electron Microscopy we analyzed the effects of the alginate lyase (AlgL), an enzyme able to degrade a wide class of polysaccharides, on theH. pylorishape, surface morphology, and biofilm adhesion properties. We demonstrated that AlgL generates a noticeable loss ofH. pyloricoccoid form in favor of the bacillary form and reduces theH. pyloriextracellular polymeric substances (EPS).

Usefulness of Helicobacter pylori eradication for precancerous lesions of the gastric remnant

BACKGROUND AND AIM

Secondary stomach cancer in lesions of the remnant stomach occurs relatively soon after distal gastrectomy using the Billroth I reconstruction procedure. Prophylactic eradication of Helicobacter pylori after endoscopic resection of early gastric cancer should be used to prevent the development of metachronous gastric carcinoma. However, the effect of H. pylori eradication on the gastric remnant has not been clearly determined.

METHODS

Eight patients who were H. pylori-positive after distal gastrectomy for primary gastric cancer underwent eradication therapy and were followed by endoscopy for 9 years. Upper gastroenteroscopy series were done before and at 1, 3, 5, 7 and 9 years after eradication, and biopsy specimens were taken from the lesser and greater curvatures, respectively. Histological changes, including chronic inflammation, activity, atrophy, and intestinal metaplasia, were evaluated using the updated Sydney system.

RESULTS

Successful eradication was confirmed using the urea breath test in all eight patients. Chronic inflammation scores were improved after eradication at both the lesser (mean scores ± SD: before eradication, 2.9±0.5; 1 year after, 2.3±0.4; 3 years, 1.8±0.3; 5 years, 1.5±0.3; 7 years, 1.3±0.3; and 9 years, 1.0±0.3) and greater curvatures (before, 2.9±0.4; 1 year after, 1.9±0.3; 3 years, 1.4±0.4; 5 years, 1.3±0.3; 7 years, 1.1±0.2; and 9 years, 0.6±0.3). Atrophy scores improved more quickly after eradication than chronic inflammation scores at both the lesser (before, 2.4±0.5; 1 year after, 1.8±0.4; 3 years, 0.8±0.3; 5 years, 0.3±0.1; 7 years, 0.0; and 9 years, 0.0) and greater curvatures (before, 2.2±0.4; 1 year after, 1.3±0.3; 3 years, 0.5±0.3; 5 years, 0.0; 7 years, 0.0; and 9 years, 0.0). No secondary stomach cancers were found on endoscopy.

CONCLUSIONS

Undergoing H. pylori eradication improved possible precancerous lesions of the gastric remnant among patients who had undergone distal gastrectomy. Prophylactic H. pylori eradication in the gastric remnant may be useful in preventing the development of metachronous gastric carcinoma.

A MDM2-dependent positive-feedback loop is involved in inhibition of miR-375 and miR-106b induced by Helicobacter pylori lipopolysaccharide

Dysregulation of microRNAs (miRNAs) has been linked to virulence factors of Helicobacter pylori and shown to contribute to the progression of gastric cancer. However, the mechanisms of these processes remain poorly understood. The aim of this study was to investigate the mechanisms by which lipopolysaccharide (LPS), a virulence factor of H. pylori, regulates miR-375 and miR-106b expression in gastric epithelial cells. The results show that LPS from H. pylori 26695 downregulated the expression of miR-375 and miR-106b in gastric epithelial cells, and low levels of Dicer were also observed. Downregulation of miR-375 was found to increase expression of MDM2 with SP1 activation. Overexpression of MDM2 inhibited Dicer by repressing p63 to create a positive-feedback loop involving SP1/MDM2/p63/Dicer that leads to inhibition of miR-375 and miR-106b expression. In addition, we demonstrated that JAK1 and STAT3 were downstream target genes of miR-106b. H. pylori LPS also enhanced the tyrosine phosphorylation of JAK1, JAK2 and STAT3. Together, these results provide insight into the regulatory mechanisms of MDM2 on H. pylori LPS-induced specific miRNAs, and furthermore, suggest that gastric epithelial cells treated with H. pylori LPS may be susceptible to JAK/STAT3 signal pathway activation via inhibition of miR-375 and miR-106b.

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.

Potential mechanism of corpus-predominant gastritis after PPI therapy in Helicobacter pylori-positive patients with GERD

The long-term use of proton pump inhibitors (PPIs) exacerbates corpus atrophic gastritis in patients with Helicobacter pylori (H. pylori) infection. To identify a potential mechanism for this change, we discuss interactions between pH, bile acids, and H. pylori. Duodenogastric reflux, which includes bile, occurs in healthy individuals, and bile reflux is increased in patients with gastroesophageal reflux disease (GERD). Diluted human plasma and bile acids have been found to be significant chemoattractants and chemorepellents, respectively, for the bacillus H. pylori. Although only taurine conjugates, with a pKa of 1.8-1.9, are soluble in an acidic environment, glycine conjugates, with a pKa of 4.3-5.2, as well as taurine-conjugated bile acids are soluble in the presence of PPI therapy. Thus, the soluble bile acid concentrations in the gastric contents of patients with GERD after continuous PPI therapy are considerably higher than that in those with intact acid production. In the distal stomach, the high concentration of soluble bile acids is likely to act as a bactericide or chemorepellent for H. pylori. In contrast, the mucous layer in the proximal stomach has an optimal bile concentration that forms chemotactic gradients with plasma components required to direct H. pylori to the epithelial surface. H. pylori may then colonize in the stomach body rather than in the pyloric antrum, which may explain the occurrence of corpus-predominant gastritis after PPI therapy in H. pylori-positive patients with GERD.

Characteristic epithelium with low-grade atypia appears on the surface of gastric cancer after successful Helicobacter pylori eradication therapy

BACKGROUND

The incidence of gastric cancer after successful Helicobacter pylori eradication has been increasing. We previously reported that epithelium with low-grade atypia (ELA) appeared on the surface of gastric cancer after H. pylori eradication. Here, we investigate the clinical and biological characteristics of such ELA.

METHODS

We studied 27 cases of gastric cancer detected after successful H. pylori eradication therapy. We examined the prevalence of ELA among these cases and its significance for endoscopic discovery after H. pylori eradication. We additionally investigated the mucus, p53 and Ki67 expressions in ELA.

RESULTS

Epithelium with low-grade atypia that continuous with the gastric tumor was detected in 22 of 27 cases (81%), a significantly greater percentage than that for controls (p < 0.01). We found that gastric-type mucin was frequently expressed in this epithelium. Neither p53- nor Ki67-positive cells were found in ELA, irrespective of their expression in tumor tissue. The presence of ELA was positively correlated with the clinical interval between H. pylori eradication and gastric cancer detection.

CONCLUSIONS

Epithelium with low-grade atypia on gastric cancer tissue, which may develop from gastric cancer cells, is frequently present after successful eradication therapy. This phenomenon could influence the practice of endoscopic diagnosis of gastric cancers.

Cholesterol glucosylation by Helicobacter pylori delays internalization and arrests phagosome maturation in macrophages

BACKGROUND/PURPOSE

Helicobacter pylori colonizes the human stomach and contributes to chronic inflammation of the gastric mucosa. H. pylori persistence occurs because of insufficient eradication by phagocytic cells. A key factor of H. pylori, cholesterol-α-glucosyltransferase encoded by capJ that extracts host cholesterol and converts it to cholesteryl glucosides, is important to evade host immunity. Here, we examined whether phagocytic trafficking in macrophages was perturbed by capJ-carrying H. pylori.

METHODS

J774A.1 cells were infected with H. pylori at a multiplicity of infection of 50. Live-cell imaging and confocal microscopic analysis were applied to monitor the phagocytic trafficking events. The viability of H. pylori inside macrophages was determined by using gentamicin colony-forming unit assay. The phagocytic routes were characterized by using trafficking-intervention compounds.

RESULTS

Wild type (WT) H. pylori exhibited more delayed entry into macrophages and also arrested phagosome maturation more than did capJ knockout mutant. Pretreatment of genistein and LY294002 prior to H. pylori infection reduced the internalization of WT but not capJ-knockout H. pylori in macrophages.

CONCLUSION

Cholesterol glucosylation by H. pylori interferes with phagosome trafficking via a lipid-raft and PI3K-dependent manner, which retards engulfment of bacteria for prolonged intracellular survival of H. pylori.

Pathology of the exotic companion mammal gastrointestinal system

A variety of disease agents can affect the gastrointestinal tract of the exotic companion mammal, some of which can pose zoonotic health concerns. Many conditions present with nonspecific clinical signs (lethargy, variable degrees of diarrhea, and for most sick rodents, presenting hunched with spiky fur), necessitating additional laboratory testing to reach a diagnosis. Primary tumors of the digestive tract are also presented as well as miscellaneous conditions ranging from toxins to trauma.

Helicobacter pylori infection in older people

Since the discovery of Helicobacter pylori (H. pylori) infection as the major cause of gastroduodenal disorders three decades ago, H. pylori has been the focus of active research and debate in the scientific community. Its linkage to several diseases, such as peptic ulcer disease, gastritis and gastric malignancy is incontestable. In particular, it has been noticed that, as the aged population is increasing worldwide, older people are at increased risk of developing several gastroduodenal diseases and related complications. At the same time, gastric cancer is definitely more frequent in elderly than in adult and young people. In addition, it has been showed that peptic ulcer and related complications occur much more commonly in aged individuals than in young people, resulting in a significantly higher mortality. Although this infection plays a crucial role in gastrointestinal disorders affecting all age groups and in particular older people, only a few studies have been published regarding the latter. This article presents an overview of the epidemiology, diagnosis, clinical manifestations and therapy of H. pylori infection in elderly people.

Neonatal thymectomy favors Helicobacter pylori-promoted gastric mucosa-associated lymphoid tissue lymphoma lesions in BALB/c mice

Neonatal thymectomy in BALB/c mice has been described as a model of gastric mucosa-associated lymphoid tissue (MALT) lymphoma (GML). By using this experimental system, we screened, for the first time to our knowledge, Helicobacter pylori GML-associated strains for their capacity to promote disease. A cohort of BALB/c mice underwent thymectomy at day 3 after birth (d3Tx). Successful thymic ablation was evaluated by the degree of lymphopenia in blood samples collected at 4 weeks of age. d3Tx and non-thymectomized controls were infected with either GML strains (B38 or B47) or control strains (SS1 or TN2GF4). Gastric samples collected at 6, 12, and 18 months after infection were studied for bacteria content, and submitted to histological, immunochemical, molecular, and immunological analyses. Severe gastric inflammation was only observed in d3Tx mice. In these animals, the gastric lamina propria was infiltrated with lymphoid cells organized in follicles composed of B cells with few infiltrating T cells. PCR of D/J IgH gene segments proved the monoclonality of infiltrating B cells, which strongly correlated with the presence of lymphoepithelial lesions. B-cell infiltrates were particularly prominent in mice infected with the B47-GML strain. No pathological changes were detected in noninfected d3Tx mice. We identified new H. pylori isolates adapted to the mouse stomach with high potential of GML development, which is only revealed in hosts rendered lymphopenic by neonatal thymic ablation.

Special licorice extracts containing lowered glycyrrhizin and enhanced licochalcone A prevented Helicobacter pylori-initiated, salt diet-promoted gastric tumorigenesis

OBJECTIVE

In spite of cytoprotective and anti-inflammatory actions, conventional licorice extracts (c-lico) were limitedly used due to serious side effects of glycyrrhizin. As our group had successfully isolated special licorice extracts (s-lico) lowering troublesome glycyrrhizin, but increasing licochalcone A, we have compared anti-inflammatory, antioxidative, and cytoprotective actions of s-lico and c-lico against either in vitro or in vivo Helicobacter pylori infection.

METHODS

RT-PCR and Western blot were performed to check anti-inflammatory action and electron spin resonance (ESR) and DCFDA spectroscopy to check antioxidative action. s-lico or c-lico was pretreated 1 hours before H. pylori infection on AGS cells. Interleukin-10 deficient mice inoculated H. pylori and followed with high salt containing pallet diets to produce H. pylori-associated chronic atrophic gastritis and gastric tumors, during which s-lico or c-lico-containing pellet diets were administered up to 24 weeks.

RESULTS

s-lico had fabulous efficacy on scavenging ROS which was further confirmed by DCFDA study and ESR measurement. The expressions of COX-2, iNOS, VEGF, and IL-8 were increased after H. pylori infection, of which levels were significantly decreased with s-lico in a dose-dependent manner. s-lico significantly ameliorated hypoxia-induced or H. pylori-induced angiogenic activities. s-lico significantly ameliorated H. pylori-induced gastric damages as well as gastritis. Our animal model showed significant development of gastric tumors including adenoma and dysplasia relevant to H. pylori infection, and s-lico administration significantly attenuated incidence of H. pylori-induced gastric tumorigenesis.

CONCLUSIONS

Special licorice extracts can be anticipating substance afforded significant attenuation of either H. pylori-induced gastritis or tumorigenesis based on potent antioxidative, anti-inflammatory, and antimutagenic actions.

Does long-term use of silver nanoparticles have persistent inhibitory effect on H. pylori based on Mongolian gerbil's model?

BACKGROUND

It is urgent to find alternative agents due to increasing failure rate of Helicobacter pylori (H. pylori) eradication. The study surveyed the long-term effect of silver nanoparticles (AgNP) on H. pylori based on Mongolian gerbil's model.

MATERIALS AND METHODS

Fifty gerbils were randomly allocated to six groups (A-F). Group (Gr) A: the gerbils were fed with broth; Gr B and D: the gerbils were fed with AgNP/clay complex (0.1% of weight); Gr C and E: the gerbils were fed with AgNP/clay complex(1% of weight); and Gr D, E, and F: the gerbils were inoculated with H. pylori. At the 20th experimental week, the gerbils were sacrificed. Histology was evaluated according to the classification of the Sydney system. P < 0.05 was considered to be statistically significant.

RESULTS

The AgNP/clay has more obvious inhibitory effect on H. pylori in vitro. There was a trend of higher concentrations of AgNP with stronger inhibitory effect on H. pylori growth (P = 0.071). There were no significant differences of inflammation among groups D, E, and F (P = 0.688).

CONCLUSION

AgNP/clay would be a potential and safe agent for inhibiting H. pylori. It should be helpful for eradication of H. pylori infection.

Helicobacter pylori eradication for preventing gastric cancer

Helicobacter pylori (H. pylori) infection is a major risk factor for gastric cancer (GC) development, which is one of the most challenging malignant diseases worldwide with limited treatments. In the multistep pathogenesis of GC, H. pylori infection slowly induces chronic active gastritis, which progresses through the premalignant stages of atrophic gastritis, intestinal metaplasia, and dysplasia, and then finally to GC. Although eradication of H. pylori is a reasonable approach for the prevention of GC, there have been some contradictory reports, with only some long-term follow-up data showing efficacy of this approach. The inconsistencies are likely due to the insufficient number of participants, relatively short follow-up periods, poor quality of study designs, and the degree and extent of preneoplastic changes at the time of H. pylori eradication. This review analyzes recent high-quality studies to resolve the discrepancies regarding the eradication of H. pylori for GC prevention. The relationship between H. pylori eradication and GC/precancerous lesions/metachronous GC is examined, and the cost-effectiveness of this strategy in the prevention of GC is assessed. Although it is assumed that eradication of H. pylori has the potential to prevent GC, the feasibility and appropriate timing of this strategy for cancer prevention remain to be determined. As a result, additional well-designed trials with longer follow-up periods are needed to clarify this issue.

Gastrointestinal malignancy and the microbiome

Microbial species participate in the genesis of a substantial number of malignancies-in conservative estimates, at least 15% of all cancer cases are attributable to infectious agents. Little is known about the contribution of the gastrointestinal microbiome to the development of malignancies. Resident microbes can promote carcinogenesis by inducing inflammation, increasing cell proliferation, altering stem cell dynamics, and producing metabolites such as butyrate, which affect DNA integrity and immune regulation. Studies in human beings and rodent models of cancer have identified effector species and relationships among members of the microbial community in the stomach and colon that increase the risk for malignancy. Strategies to manipulate the microbiome, or the immune response to such bacteria, could be developed to prevent or treat certain gastrointestinal cancers.