The translation of Helicobacter pylori basic research to patient care

Antiurease Activity of Antibiotics: In Vitro, In Silico, Structure Activity Relationship, and MD Simulations of Cephalosporins and Fluoroquinolones

Helicobacter pylori infection is widespread in 50% of the world's population and is associated with gastric ulcers and related disorders that ultimately culminate in gastric cancer. Levofloxacin-based, or clarithromycin-based, triple therapy is frequently used to inhibit the bacterial urease enzyme for the eradication of H. pylori. A comprehensive investigation based on the urease inhibitory profiles of antibiotics and their computational implications is lacking in the scientific literature. The present study was aimed specifically to determine the antiurease activities within the realms of cephalosporins and fluoroquinolones by in vitro methods supported with in silico investigations. The results demonstrate the jack bean urease inhibitory activity of cephalosporins, wherein cefadroxil, cefpodoxime, cefotaxime, and cefaclor displayed inhibitions (IC50 21.35 ± 0.64 to 62.86 ± 0.78 μM) compared with the standard thiourea (IC50 21.25 ± 0.15 μM). Among fluoroquinolones, levofloxacin, ofloxacin, and gemifloxacin (IC50 7.24 ± 0.29 to 16.53 ± 0.85 μM) unveiled remarkable inhibitory profiles. Levofloxacin and ofloxacin exhibited competitive inhibition against the said enzyme. Ciprofloxacin and moxifloxacin displayed weak urease inhibitions. During molecular docking studies, Asp362, Gly279, Arg338, Asn168, Asp223, Gln364, and Met366 were involved in hydrogen bonding in fluoroquinolones, and hydrogen bonding was established with Arg338, His248, Asn168 residues, and metal Ni601 and Ni602 of the enzyme. MD simulations and MMPBSA results demonstrated the existence of significant protein-ligand binding. Overall, these results warrant further investigations into the significance of these active molecules in relation to their inhibitory potential against the targeted urease enzyme.

Evaluation of the Inflammatory Response After Eradication of Helicobacter pylori in Patients With Familial Mediterranean Fever

PURPOSE

Evaluation of the inflammatory response after Helicobacter pylori (Hp) eradication in patients with Familial Mediterranean Fever (FMF) during the non-attack period and determining whether there is a change in the ongoing inflammation during the non-attack period.

MATERIALS AND METHODS

Sixty-four patients, who have not been eradicated for Hp in the last 2 years, diagnosed with FMF, and evaluated in the non-attack period, were included in the study. Hp eradication therapy was administered to patients who were found to be Hp-positive. C-reactive protein (CRP), high-sensitive C-reactive protein (hs-CRP), interleukin-6, interleukin-8, tumor necrosis factor-alpha, and serum amyloid A values were compared between the groups before and after eradication.

RESULTS

CRP and hs-CRP levels were found to be statistically higher in the FMF group than in the control group. A statistically significant decrease was found in the values of CRP and hs-CRP, in the number of patients with attacks, and in attack frequency after eradication in the Infected Patients compared to the values before eradication.

CONCLUSIONS

We determined a decrease in CRP and hs-CRP values, the number of patients with attacks, and attack frequency with the eradication of Infected Patients. In patients with FMF, in whom it has been proven by different studies that the inflammation continues during the non-attack period, it may be recommended to investigate the presence of Hp infection, which is thought to contribute to this inflammation and to give Hp eradication therapy to patients who are found positive to reduce the development of secondary complications caused by chronic inflammation.

Effects of Helicobacter pylori on the expression of the FTO gene and its biological role in gastric cancer

Helicobacter pylori (Hp) is a primary risk factor for gastric cancer. The fat mass and obesity-associated (FTO) gene is associated with the development and progression of various cancer types such as glioma, leukemia, breast cancer and colorectal cancer. The aim of the present study was to investigate the effect of Hp infection on the expression of FTO and its roles in gastric cancer. It was found that the expression levels of both FTO mRNA and protein were significantly increased in Hp-infected human gastric mucosal epithelial cells and Mongolian gerbil gastric tissues. The expression of FTO in gastric cancer tissues was higher than that in para-cancer tissues. Data from The Cancer Genome Atlas demonstrated that FTO expression in gastric cancer tissues was significantly higher than that in normal tissues. Patient survival rate was significantly decreased in patients with high expression levels of FTO. It was also demonstrated that FTO expression was associated with several pathological parameters, such as tumor stage, metastasis stage and the American Joint Committee on Cancer stage. The FTO gene was positively correlated with 16,601 genes in gastric cancer and negatively correlated with 3,623 genes. Gene Ontology enrichment analysis demonstrated that FTO was significantly enriched in the regulation of gene expression and oxidative RNA demethylase activity, and it was associated with components such as the RNA N6-methyladenosine methyltransferase complex and nuclear speckle. In addition, knockdown of the FTO gene inhibited the migration and invasion of Hp-infected cells. In conclusion, the data suggests that Hp infection leads to upregulation of the FTO gene, which may be related to patient survival rate, tumor staging and other pathological parameters of patients with gastric cancer. It also suggests that FTO promotes proliferation and migration of gastric cancer cells, which may be involved in the pathogenesis of Hp-induced gastric cancer.

The JMJD Family Histone Demethylases in Crosstalk Between Inflammation and Cancer

Inflammation has emerged as a key player in regulating cancer initiation, progression, and therapeutics, acting as a double edged sword either facilitating cancer progression and therapeutic resistance or inducing anti-tumor immune responses. Accumulating evidence has linked the epigenetic modifications of histones to inflammation and cancer, and histone modifications-based strategies have shown promising therapeutic potentials against cancer. The jumonji C domain-containing (JMJD) family histone demethylases have exhibited multiple regulator functions in inflammatory processes and cancer development, and a number of therapeutic strategies targeting JMJD histone demethylases to modulate inflammatory cells and their products have been successfully evaluated in clinical or preclinical tumor models. This review summarizes current understanding of the functional roles and mechanisms of JMJD histone demethylases in crosstalk between inflammation and cancer, and highlights recent clinical and preclinical progress on harnessing the JMJD histone demethylases to regulate cancer-related inflammation for future cancer therapeutics.

The impact of oral ciprofloxacin on the structure and functions of rat gastric mucosa

Ciprofloxacin (CPX), is a fluoroquinolone antibiotic used to treat a number of gram-negative and gram-positive bacterial infections. Ciprofloxacin can cause severe side effects, ranging from tendon problems, nerve damage, to serious mood or behavior changes.

The purpose of this study was to investigate how ciprofloxacin affects gastric cell lines in rats with a distinctive emphasis on physiological, histopathological, and bacteriological changes. Male albino rats (n = 21) were distributed into three groups; control, CPX, and CPX-withdrawal groups. The treated rats were given CPX tablets (12.5 mg/kg) dissolved in carboxymethyl cellulose (CMC) 0.5% orally once daily via gavage for sixty consecutive days. Control rats received only the vehicle. The withdrawal group was treated for 60 days and the drug was withdrawn for another sixty days. After completion of the experiment, all rats were sacrificed and gastric tissues were treated for light, immunohistochemical, and scanning electron microscopic examination. Image J software was used to measure immune-labeled gastric epithelial cells. Blood samples were also collected for H. Pylori immunoglobulins IgM, IgA, and IgG. Results showed that treated rats acquired significantly strongly positive tumor necrosis factor (TNFα) and significant reduction of serum level of H. pylori IgM, IgA, and IgG in all the study groups. It could be concluded that prolonged oral CPX administration to albino rats changes the gastric mucosal architecture and bacteriology.

The association of Helicobacter Pylori infection with dyslipidaemia and other atherogenic factors in dyspeptic patients at St. Paul's Hospital Millennium Medical College

Background

Studies showed that more than half of Ethiopians were presumed to be chronically infected with H. pylori. Nowadays, evidence has come to the literature strongly suggesting the potential association between H. pylori and extra gastric disorders including atherosclerosis.

Objective

To assess the association of helicobacter pylori infection with dyslipidaemia and other atherogenic factors in dyspeptic patients at St. Paul's Hospital Millennium Medical College, from November 2019 to June 2020.

Materials and methods

This institution-based cross-sectional study was examining 346 dyspeptic patients at SPHMMC from November 2019 to June 2020. A structured questionnaire was used to collect socio-demography data and anthropometric measurement was taken. Biochemical parameters were measured in serum samples by using Cobas 6000 clinical chemistry analyzer. Data were coded and entered into a statistical package for social sciences (SPSS) version 23 for analysis. Risk factors were identified using logistic regression. Hence, a bivariate logistic regression analysis test was conducted and variables with a p < 0.25 were included in the multivariate logistic regression model. P-values ≤0.05 were considered as a cut point for statistical significance in the final model.

Results

An overall prevalence of dyslipidemia among study participants was 253 (73.12 %). Among those who tested positive for H. pylori, 119/174 (68.39 %) had dyslipidemia in at least one lipid profile, while 8 (4.60%) had dyslipidemia in all four lipid profiles. After adjusting for traditional dyslipidemia risk factors, age >45 (AOR 4.864, 95% CI 2.281–4.080, P < 0.001), systolic blood pressure >120mmHg (AOR 1.036, 95% CI 1.009–1.065, P = 0.036) and being H. Pylori seropositive (AOR 0.555, 95% CI 0.318–0.967, P = 0.038) were an independent predictors of dyslipidemia.

Conclusion

This study reported that more than two-thirds of the H. pylori seropositive groups had exhibited dyslipidemia in at least one lipid profile, which can accelerate the incidence of atherosclerosis process.

Oral and gastric microbiome in relation to gastric intestinal metaplasia

Evidence suggests that Helicobacter pylori plays a role in gastric cancer (GC) initiation. However, epidemiologic studies on the specific role of other bacteria in the development of GC are lacking. We conducted a case-control study of 89 cases with gastric intestinal metaplasia (IM) and 89 matched controls who underwent upper gastrointestinal endoscopy at three sites affiliated with NYU Langone Health. We performed shotgun metagenomic sequencing using oral wash samples from 89 case-control pairs and antral mucosal brushing samples from 55 case-control pairs. We examined the associations of relative abundances of bacterial taxa and functional pathways with IM using conditional logistic regression with and without elastic-net penalty. Compared with controls, oral species Peptostreptococcus stomatis, Johnsonella ignava, Neisseria elongata and Neisseria flavescens were enriched in cases (odds ratios [ORs] = 1.29-1.50, P = .004-.01) while Lactobacillus gasseri, Streptococcus mutans, S parasanguinis and S sanguinis were under-represented (ORs = 0.66-0.76, P = .006-.042) in cases. Species J ignava and Filifactor alocis in the gastric microbiota were enriched (ORs = 3.27 and 1.43, P = .005 and .035, respectively), while S mutans, S parasanguinis and S sanguinis were under-represented (ORs = 0.61-0.75, P = .024-.046), in cases compared with controls. The lipopolysaccharide and ubiquinol biosynthesis pathways were more abundant in IM, while the sugar degradation pathways were under-represented in IM. The findings suggest potential roles of certain oral and gastric microbiota, which are correlated with regulation of pathways associated with inflammation, in the development of gastric precancerous lesions.

Microbial-Driven Immunological Memory and Its Potential Role in Microbiome Editing for the Prevention of Colorectal Cancer

Over the last several years, many advances have been made in understanding the role of bacteria in the pathogenesis of gastrointestinal cancers. Beginning with Helicobacter pylori being recognized as the first bacterial carcinogen and the causative agent of most gastric cancers, more recent studies have examined the role of enteric microbes in colorectal cancer. In the digestive tract, these communities are numerous and have a complex interrelationship with local immune/inflammatory responses that impact the health of the host. As modifying the microbiome in the stomach has decreased the risk of gastric cancer, modifying the distal microbiome may decrease the risk of colorectal cancers. To date, very few studies have considered the notion that mucosal lymphocyte-dependent immune memory may confound attempts to change the microbial components in these communities. The goal of this review is to consider some of the factors impacting host-microbial interactions that affect colorectal cancer and raise questions about how immune memory responses to the local microbial consortium affect any attempt to modify the composition of the intestinal microbiome.

Cohort study of Helicobacter pylori infection and the risk of incident osteoporosis in women

BACKGROUND AND AIM

Previous studies suggested an association between Helicobacter pylori infection and osteoporosis; however, large-scale longitudinal studies are lacking to elucidate this association.

METHODS

A cohort study of 10 482 women without osteoporosis at baseline who participated in a repeated health-screening examination including an H. pylori-specific immunoglobulin G antibody test was conducted to evaluate the association between H. pylori and osteoporosis development. Osteoporosis was diagnosed using dual-energy X-ray absorptiometry.

RESULTS

During the 77 515.3 person-years of follow-up, women with H. pylori infection had a higher rate of incident osteoporosis than those who were uninfected. In a multivariable model adjusted for age, body mass index (BMI), menopausal status, smoking status, regular exercise, comorbidities (including hypertension, diabetes mellitus, dyslipidemia, stroke, or ischemic heart disease), and concomitant medications, the hazard ratio (HR) for incident osteoporosis in women with H. pylori infection compared with that in women without infection was 1.23 (95% confidence interval [CI], 1.03-1.45). The association between H. pylori and osteopenia development was also evident. In the multivariable analysis, menopause (HR, 1.68; 95% CI, 1.31-2.16) and increasing age (HR, 1.07; 95% CI, 1.06-1.08) were identified as significant risk factors for osteoporosis, whereas higher BMI (HR, 0.84; 95% CI, 0.81-0.87) was a protective factor for the risk of osteoporosis.

CONCLUSIONS

In this cohort study, H. pylori infection was associated with an increased risk of osteoporosis, independent of risk factors and confounding factors.

Helicobacter pylori infection is associated with diabetes among Chinese adults

AIMS/INTRODUCTION

Several epidemiological studies investigated the effect of Helicobacter pylori infection on diabetes, but the conclusions remained inconsistent. We aimed to explore the relationship between H. pylori infection and diabetes, as well as glycemic metabolism profiles.

MATERIALS AND METHODS

A cross-sectional study including 58,482 Chinese adults was carried out between January 2016 and December 2017. H. pylori infection was diagnosed by the 13 C-urea breath test. Multivariate regression analyses were carried out to evaluate the association of H. pylori infection with diabetes.

RESULTS

Of the 58,482 participants, 3,449 (5.9%) had diabetes. The H. pylori-positive participants had a higher rate of diabetes (7.3% vs 5.2%, P < 0.001), and higher levels of fasting plasma glucose (5.36 ± 1.12 mmol/L vs 5.28 ± 0.95 mmol/L, P < 0.001) and glycated hemoglobin A1c (5.63 ± 0.68% vs 5.57 ± 0.60%, P < 0.001) than the H. pylori negative group. Multivariate regression analyses showed that H. pylori infection was positively related to diabetes (odds ratio 1.25, 95% confidence interval 1.15-1.35). Among the H. pylori-positive participants, the elevated levels of fasting plasma glucose and glycated hemoglobin A1c were 0.033 mmol/L (95% confidence interval 0.016-0.049 mmol/L) and 0.024% (95% confidence interval 0.008-0.041%), respectively. Additionally, H. pylori infection was significantly related to diabetes in participants aged ≥44 years, but not in participants aged <44 years.

CONCLUSIONS

The present study showed that H. pylori infection is associated with diabetes among Chinese adults. More attention should be paid to adults with H. pylori infection for effective prevention of diabetes.

Histopathological Findings in Morbid Obese Patients Undergoing Laparoscopic Sleeve Gastrectomy: Does H. pylori Infection Effective on Pathological Changes?

AıM: To determine the prevalence of histopathological findings requiring clinical follow-up in morbidly obese patients undergoing laparoscopic sleeve gastrectomy (LSG) and evaluate the relationship between these findings and Helicobacter pylori as well as to add more data to the published literature in this regard. MATERıAL AND METHODS: Overall, 161 morbidly obese patients with body mass index (BMI) > 40 kg/m² who underwent LSG between May 1, 2014 and May 31, 2017 were retrospectively included in the study. The findings of the histopathological evaluation of the resected gastric material and the relationship between these findings and histopathologically detected H. pylori infection were investigated.

RESULTS

The study included 114 women (70.8%) and 47 men (29.2%). The mean age of the patients was 36.82 ± 10.41 years, and the mean BMI was 46.05 ± 3.76 kg/m². H. pylori infection was detected in 103 (64%), chronic gastritis in 156, chronic active gastritis in 47, intestinal metaplasia in eight, and atrophy in seven patients. The rate of H. pylori-associated chronic gastritis was 64%, that of chronic active gastritis was 24.2%, that of lymphoid aggregation was 62.2%, and that of intestinal metaplasia and atrophy was 3.1%. There was a significant relationship between H. pylori infection and chronic gastritis, chronic active gastritis, and lymphoid aggregation; however, no significant relationship was found between intestinal metaplasia and atrophy. CONCLUSıON: Clinicians should be aware of the histopathological findings requiring clinical follow-up for LSG-treated patients. Given the complications of H. pylori infection such as lymphoma and malignancy, periodic follow-up of patients and eradication therapy may be a suitable approach for treating intestinal metaplasia and atrophic changes.

The effect of Helicobacter pylori infection and different H. pylori components on the proliferation and apoptosis of gastric epithelial cells and fibroblasts

Background

Helicobacter pylori colonizes the human gastric mucosa, causing chronic inflammation, peptic ulcers and gastric cancer. A cascade of harmful processes results from the interaction of these bacteria with the gastric epithelium.

Aim

To investigate these processes in terms of upregulation of oxidative stress and cell apoptosis and downregulation of the pro-regenerative activity of cells.

Methods

We employed an in vivo guinea pig model at 7 or 28 days postinoculation with H. pylori, corresponding to an acute or chronic stage of infection, respectively, and an in vitro model of guinea pig primary gastric epithelial cells and fibroblasts treated with bacterial components: glycine acid extract (GE), urease subunit A (UreA), cytotoxin-associated gene A protein (CagA) and lipopolysaccharide (LPS). Cells were evaluated for metabolic activity (MTT reduction), myeloperoxidase (MPO) and metalloproteinase (MMP-9) secretion, lipid peroxidation (4-hydroxynonenal (4HNE)), migration (wound healing), proliferation (Ki-67 antigen) and cell apoptosis (TUNEL assay; Bcl-xL, Bax, Bcl-2 expression; caspase 3 cleavage).

Results

Significant infiltration of the gastric mucosa by inflammatory cells in vivo in response to H. pylori was accompanied by oxidative stress and cell apoptosis, which were more intense 7 than 28 days after inoculation. The increase in cell proliferation was more intense in chronic than acute infection. H. pylori components GE, CagA, UreA, and LPS upregulated oxidative stress and apoptosis. Only H. pylori LPS inhibited cell migration and proliferation, which was accompanied by the upregulation of MMP-9.

Conclusions

H. pylori infection induces cell apoptosis in conjunction with increased oxidative stress. Elevated apoptosis protects against deleterious inflammation and neoplasia; however, it reduces cell integrity. Upregulation of cell migration and proliferation in response to injury in the milieu of GE, CagA or UreA facilitates tissue regeneration but increases the risk of neoplasia. By comparison, downregulation of cell regeneration by H. pylori LPS may promote chronic inflammation.

Increased risk of peptic ulcer in patients with early-onset cataracts: A nationwide population-based study

Early-onset cataracts (EOC) are associated with an increased inflammatory response; therefore, a potential risk of other inflammatory diseases, like peptic ulcer, may be related. This study investigated the risk of peptic ulcer after being diagnosed with EOC. Retrospective claims data from the Taiwan National Health Insurance Research Database were analyzed. Study subjects comprised patients with EOC (International Classification of Diseases, 9th Revision, Clinical Modification [ICD-9- CM] codes 366.00, 366.01, 366.02, 366.03, 366.04, 366.09, 366.17 and 366.18), aged 20–55 years and newly diagnosed between 2000 and 2010 (n = 1910), and a comparison cohort without the disease (n = 7515). Both cohorts were followed up until 2010 to estimate the incidences of peptic ulcer. We used the Poisson regression model to compare incidence rate ratios and the 95% confidence interval (CI). Cox proportional hazards regression was used to assess the hazard ratio (HR) of peptic ulcer associated with EOC. The overall incidence rate of peptic ulcer was higher in the EOC cohort than in the comparison cohort (10.3 vs 7.68 per 1000 person-years) with an adjusted HR of 1.33 (95% CI = 1.05, 1.69). The present study suggests that patients with EOC are at an increased risk of being diagnosed with peptic ulcer in subsequent years.

Acid and the basis for cellular plasticity and reprogramming in gastric repair and cancer

Subjected to countless daily injuries, the stomach still functions as a remarkably efficient digestive organ and microbial filter. In this Review, we follow the lead of the earliest gastroenterologists who were fascinated by the antiseptic and digestive powers of gastric secretions. We propose that it is easiest to understand how the stomach responds to injury by stressing the central role of the most important gastric secretion, acid. The stomach follows two basic patterns of adaptation. The superficial response is a pattern whereby the surface epithelial cells migrate and rapidly proliferate to repair erosions induced by acid or other irritants. The stomach can also adapt through a glandular response when the source of acid is lost or compromised (that is, the process of oxyntic atrophy). We primarily review the mechanisms governing the glandular response, which is characterized by a metaplastic change in cellular differentiation known as spasmolytic polypeptide-expressing metaplasia (SPEM). We propose that the stomach, like other organs, exhibits marked cellular plasticity: the glandular response involves reprogramming mature cells to serve as auxiliary stem cells that replace lost cells. Unfortunately, such plasticity might mean that the gastric epithelium undergoes cycles of differentiation and de-differentiation that increase the risk of accumulating cancer-predisposing mutations.

Modeling Murine Gastric Metaplasia Through Tamoxifen-Induced Acute Parietal Cell Loss

Parietal cell loss represents the initial step in the sequential progression toward gastric adenocarcinoma. In the setting of chronic inflammation, the expansion of the mucosal response to parietal cell loss characterizes a crucial transition en route to gastric dysplasia. Here, we detail methods for using the selective estrogen receptor modulator tamoxifen as a novel tool to rapidly and reversibly induce parietal cell loss in mice in order to study the mechanisms that underlie these pre-neoplastic events.

A cohort study on Helicobacter pylori infection associated with nonalcoholic fatty liver disease

BACKGROUND

Previous studies have suggested a link between Helicobacter pylori (H. pylori) infection and nonalcoholic fatty liver disease (NAFLD), yet large-scale longitudinal studies are lacking to elucidate this association.

METHODS

A cohort study of 17,028 adults without NAFLD at baseline, who participated in a repeated health screening examination including an H. pylori-specific immunoglobulin G antibody test, was conducted to evaluate the association between H. pylori and NAFLD development. Fatty liver was diagnosed by ultrasonography.

RESULTS

During the 83,130 person-years follow-up, participants with H. pylori infection had a higher rate of incident NAFLD than those who were uninfected. In a multivariable model adjusted for age, sex, body mass index, smoking status, alcohol intake, regular exercise, year of screening exam, and education level, the hazard ratio (HR) for NAFLD development in participants with H. pylori infection compared to those without infection was 1.21 [95% confidence interval (CI), 1.10-1.34]. The association persisted after further adjustment for metabolic variables, inflammatory marker, and liver enzymes. The association between H. pylori and NAFLD was still evident in an analysis using fatty liver index as a surrogate marker of NAFLD. In addition, the association between H. pylori infection and incident NAFLD did not differ across clinically relevant subgroups evaluated.

CONCLUSIONS

H. pylori infection was significantly associated with the development of NAFLD, independent of metabolic and inflammatory risk factors. H. pylori infection may play a pathophysiologic role in NAFLD development, indicating that H. pylori eradication might play a role in reducing the risk of NAFLD.

Helicobacter pylori modulates cyclooxygenase-2 and 15-hydroxy prostaglandin dehydrogenase in gastric cancer

Persistent infection with Helicobacter pylori may contribute to the carcinogenesis of gastric cancer through modulating local prostaglandin E₂ (PGE₂) levels. Cyclooxygenase-2 (COX-2) and 15-hydroxy prostaglandin dehydrogenase (15-PGDH) are two key enzymes that regulate PGE₂ synthesis and inactivation, respectively. The present study was designed to investigate the expression of COX-2 and 15-PGDH in gastric cancer specimens (n=66) in comparison to that of control specimens (n=70) and, furthermore, to semi-quantitatively assess the level of COX-2 and 15-PGDH mRNA and protein in tissues with or without H. pylori infection by reverse transcription-polymerase chain reaction and immunohistochemistry, respectively. It was revealed that COX-2 was expressed in almost all gastric cancer specimens infected with H. pylori (32 out of 33 specimens), but it was also expressed in 2/3 gastric cancers without H. pylori infection (22 out of 33 specimens). By contrast, COX-2 was expressed in <1/6 control subjects regardless of H. pylori infection. Furthermore, 15-PGDH was expressed in control samples but significantly downregulated in gastric cancer specimens. H. pylori infection resulted in slight inhibition of 15-PGDH in control subjects, but significant inhibition of 15-PGDH mRNA expression and protein synthesis in the gastric cancer specimens. These findings indicated that COX-2 and 15-PGDH, the two enzymes that regulate PGE₂ levels, were significantly altered in gastric cancer, and that H. pylori may contribute to gastric carcinogenesis through modulating COX-2 and 15-PGDH mRNA expression and protein synthesis.

Human Gut Microbiota: Toward an Ecology of Disease

Composed of trillions of individual microbes, the human gut microbiota has adapted to the uniquely diverse environments found in the human intestine. Quickly responding to the variances in the ingested food, the microbiota interacts with the host via reciprocal biochemical signaling to coordinate the exchange of nutrients and proper immune function. Host and microbiota function as a unit which guards its balance against invasion by potential pathogens and which undergoes natural selection. Disturbance of the microbiota composition, or dysbiosis, is often associated with human disease, indicating that, while there seems to be no unique optimal composition of the gut microbiota, a balanced community is crucial for human health. Emerging knowledge of the ecology of the microbiota-host synergy will have an impact on how we implement antibiotic treatment in therapeutics and prophylaxis and how we will consider alternative strategies of global remodeling of the microbiota such as fecal transplants. Here we examine the microbiota-human host relationship from the perspective of the microbial community dynamics.

Helicobacter pylori-Induced Changes in Gastric Acid Secretion and Upper Gastrointestinal Disease

Appropriate management of Helicobacter pylori infection of the human stomach is evolving and remains a significant clinical challenge. Acute infection results in hypochlorhydria, whereas chronic infection results in either hypo- or hyperchlorhydria, depending upon the anatomic site of infection. Acute hypochlorhydria facilitates survival of the bacterium and its infection of the stomach. Interestingly, most patients chronically infected with H. pylori manifest a pangastritis with reduced acid secretion due to bacterial virulence factors, inflammatory cytokines, and various degrees of gastric atrophy. While these patients are predisposed to develop gastric adenocarcinoma (~1%), there is increasing evidence from population studies that they are also protected from gastroesophageal reflux disease (GERD), Barrett's esophagus (BE), and esophageal adenocarcinoma (EAC). Eradication of H. pylori, in these patients, may provoke GERD in predisposed individuals and may be a contributory factor for the rising incidence of refractory GERD, BE, and EAC observed in Westernized societies. Only ~10% of chronically infected patients, mainly the young, manifest an antral predominant gastritis with increased acid secretion due to a decrease in somatostatin and increase in gastrin secretion; these patients are predisposed to develop peptic ulcer disease. H. pylori-induced changes in acid secretion, in particular hypochlorhydria, may allow ingested microorganisms to survive transit through the stomach and colonize the distal intestine and colon. Such perturbation of gut microbiota, i.e. dysbiosis, may influence human health and disease.

Helicobacter pylori infection is an independent risk factor of early and advanced colorectal neoplasm

BACKGROUND

The role of Helicobacter pylori (H. pylori) in the development of colorectal neoplasm remains controversial. We examined the association between H. pylori infection and colorectal neoplasm in a large sample of healthy participants who underwent screening colonoscopy.

METHODS

A cross-sectional study of 8916 men, who participated in a regular health-screening examination that included an H. pylori-specific immunoglobulin G antibody test and colonoscopy, was conducted to evaluate the association between H. pylori and colorectal neoplasm.

RESULTS

Multivariable analyses adjusted for age, body mass index, smoking status, alcohol intake, regular exercise, regular aspirin use, and family history of colorectal cancer showed that the odds ratio (OR) (95% confidence interval [CI]) for any adenoma and advanced neoplasm was 1.32 (1.07-1.61) and 1.90 (1.05-3.56) in participants with H. pylori infection and without H. pylori infection, respectively. The association persisted after further adjustment for inflammatory markers or metabolic variables including fasting blood glucose, triglycerides, high-density lipoprotein-cholesterol, and low-density lipoprotein-cholesterol. Regarding the location, a positive association was confined to cases with proximal adenomas and was observed similarly in all the evaluated subgroups.

CONCLUSIONS

In a large-scale study, carefully controlled for confounding factors, involving asymptomatic participants without a history of colonoscopy, H. pylori infection was significantly associated with the risk of any colorectal adenoma and advanced colorectal neoplasm. Prospective studies are necessary to determine whether H. pylori eradication can reduce this risk.

Helicobacter pylori is associated with dyslipidemia but not with other risk factors of cardiovascular disease

Epidemiologic and clinical data suggest that Helicobacter pylori infection is a contributing factor in the progression of atherosclerosis. However, the specific cardiovascular disease risk factors associated with H. pylori remain unclear. We performed a cross-sectional study of 37,263 consecutive healthy subjects who underwent a routine health check-up. In multivariable log Poisson regression models adjusted for potential confounders, the associations of H. pylori seropositivity with higher LDL-C (relative risk [RR], 1.21; 95% confidence interval [CI], 1.12–1.30) and lower HDL-C level (RR, 1.10; 95% CI, 1.01–1.18) were significant and independent. In multiple linear regression analyses, H. pylori infection was significantly associated with higher total cholesterol level (coefficient = 2.114, P < 0.001), higher LDL-C level (coefficient = 3.339, P < 0.001), lower HDL-C level (coefficient = −1.237, P < 0.001), and higher diastolic blood pressure (coefficient = 0.539, P = 0.001). In contrast, H. pylori infection was not associated with obesity-related parameters (body mass index, waist circumference), glucose tolerance (fasting glucose, glycated hemoglobin), and systolic blood pressure. We found that H. pylori infection was significantly and independently associated with dyslipidemia, but not with other cardiometabolic risk factors, after adjusting for potential risk factors of atherosclerosis.

TLR9 activation suppresses inflammation in response to Helicobacter pylori infection

Helicobacter pylori (H. pylori) induces chronic gastritis in humans, and infection can persist for decades. One H. pylori strain-specific constituent that augments disease risk is the cag pathogenicity island. The cag island encodes a type IV secretion system (T4SS) that translocates DNA into host cells. Toll-like receptor 9 (TLR9) is an innate immune receptor that detects hypo-methylated CpG DNA motifs. In this study, we sought to define the role of the H. pylori cag T4SS on TLR9-mediated responses in vivo. H. pylori strain PMSS1 or its cagE^- mutant, which fails to assemble a T4SS, were used to infect wild-type or Tlr9^-/- C57BL/6 mice. PMSS1-infected Tlr9^-/- mice developed significantly higher levels of inflammation, despite similar levels of colonization density, compared with PMSS1-infected wild-type mice. These changes were cag dependent, as both mouse genotypes infected with the cagE^- mutant only developed minimal inflammation. Tlr9^-/- genotypes did not alter the microbial phenotypes of in vivo-adapted H. pylori strains; therefore, we examined host immunological responses. There were no differences in levels of T_H1 or T_H2 cytokines in infected mice when stratified by host genotype. However, gastric mucosal levels of IL-17 were significantly increased in infected Tlr9^-/- mice compared with infected wild-type mice, and H. pylori infection of IL-17A^-/- mice concordantly led to significantly decreased levels of gastritis. Thus loss of Tlr9 selectively augments the intensity of IL-17-driven immune responses to H. pylori in a cag T4SS-dependent manner. These results suggest that H. pylori utilizes the cag T4SS to manipulate the intensity of the host immune response.

Role of Helicobacter pylori infection in generation of gastric cancer stem cells

Helicobacter pylori (H. pylori) is a key cause of gastric cancer, and gastric cancer stem cells play an important role in the development of gastric cancer. Therefore in this paper, we try to explore the relationship between H. pylori infection and stem cells in gastric cancer. H. pylori infection promotes the generation of gastric cancer stem cells through the epithelial-mesenchymal transition (EMT). In addition, H. pylori participates in the processes of the formation and progression of gastric cancer stem cells by affecting related signal pathways, such as Wnt/β-catenin, Hh/SHH, Notch, FGF/BMP. On this basis, we disscuss the challenges and future directions in the research of H. pylori infection and gastric cancer stem cells.

Pathogenic Helicobacter pylori strains translocate DNA and activate TLR9 via the cancer-associated cag type IV secretion system

Helicobacter pylori is the strongest identified risk factor for gastric cancer, the third most common cause of cancer-related death worldwide. An H. pylori constituent that augments cancer risk is the strain-specific cag pathogenicity island, which encodes a type IV secretion system (T4SS) that translocates a pro-inflammatory and oncogenic protein, CagA, into epithelial cells. However, the majority of persons colonized with CagA⁺H. pylori strains do not develop cancer, suggesting that other microbial effectors also play a role in carcinogenesis. Toll-like receptor 9 (TLR9) is an endosome bound, innate immune receptor that detects and responds to hypo-methylated CpG DNA motifs that are most commonly found in microbial genomes. High expression tlr9 polymorphisms have been linked to the development of premalignant lesions in the stomach. We now demonstrate that levels of H. pylori-mediated TLR9 activation and expression are directly related to gastric cancer risk in human populations. Mechanistically, we show for the first time that the H. pylori cancer-associated cag T4SS is required for TLR9 activation and that H. pylori DNA is actively translocated by the cag T4SS to engage this host receptor. Activation of TLR9 occurs through a contact-dependent mechanism between pathogen and host, and involves transfer of microbial DNA that is both protected as well as exposed during transport. These results indicate that TLR9 activation via the cag island may modify the risk for malignancy within the context of H. pylori infection and provide an important framework for future studies investigating the microbial-epithelial interface in gastric carcinogenesis.

The Helicobacter pylori Cag Pathogenicity Island Protein Cag1 is Associated with the Function of T4SS

The human pathogen Helicobacter pylori is involved in gastric diseases ranging from gastritis to gastric cancer. Virulent strains harboring the cag pathogenicity island (cag PAI) which encode a Type IV Secretion System (T4SS) can induce pro-inflammatory cytokines such as interleukin-8 and deliver their major effector proteins CagA into the gastric cells. While a subset of cag PAI genes have been identified to be the homologues of T4SS genes from Agrobacterium tumefaciens, a majority have unknown functions. We have identified one of such proteins, Cag1, which was predicted to be a non-classically secreted and virulent protein. Our results showed that Cag1 is a membrane-associated protein essential for the induction of multiple cytokine secretions, and cag1-deficient mutant has partial influence on CagA translocation; while the protein itself was not injected into host cells. Our data indicated that Cag1 is located in the bacterial membrane and is associated with the function of T4SS.

An overview of new biomolecular pathways in pathogen-related cancers

Cancer molecular pathways are combinations of metabolic processes deregulated in neoplastic cells. Besides pathways specific to tissues from which cancers originate, common neoplastic traits are present among most tumors. Hanahan and Weinberg have described the most critical 'hallmarks' shared by many cancer types. In recent years, cancer stem cell specific properties and pathways have also been identified. Other altered pathways are peculiar of cancer type and cancer stage, even in different cancer stem cell types. In pathogen-related tumors, the alteration of inflammatory and immunologic response along with impairment of cell cycle control represents key molecular events of tumor progression. This article summarizes the recent discoveries of new altered pathways in cancer and their importance in cancer diagnosis and tailored therapies.

Regulation of Rac1 and Reactive Oxygen Species Production in Response to Infection of Gastrointestinal Epithelia

Generation of reactive oxygen species (ROS) during infection is an immediate host defense leading to microbial killing. APE1 is a multifunctional protein induced by ROS and after induction, protects against ROS-mediated DNA damage. Rac1 and NAPDH oxidase (Nox1) are important contributors of ROS generation following infection and associated with gastrointestinal epithelial injury. The purpose of this study was to determine if APE1 regulates the function of Rac1 and Nox1 during oxidative stress. Gastric or colonic epithelial cells (wild-type or with suppressed APE1) were infected with Helicobacter pylori or Salmonella enterica and assessed for Rac1 and NADPH oxidase-dependent superoxide production. Rac1 and APE1 interactions were measured by co-immunoprecipitation, confocal microscopy and proximity ligation assay (PLA) in cell lines or in biopsy specimens. Significantly greater levels of ROS were produced by APE1-deficient human gastric and colonic cell lines and primary gastric epithelial cells compared to control cells after infection with either gastric or enteric pathogens. H. pylori activated Rac1 and Nox1 in all cell types, but activation was higher in APE1 suppressed cells. APE1 overexpression decreased H. pylori-induced ROS generation, Rac1 activation, and Nox1 expression. We determined that the effects of APE1 were mediated through its N-terminal lysine residues interacting with Rac1, leading to inhibition of Nox1 expression and ROS generation. APE1 is a negative regulator of oxidative stress in the gastrointestinal epithelium during bacterial infection by modulating Rac1 and Nox1. Our results implicate APE1 in novel molecular interactions that regulate early stress responses elicited by microbial infections.

Helicobacter pylori infection of the gastric mucosa is largely lifelong leading to continued stimulation of immune cells. This results in the generation of reactive oxygen species (ROS) which are produced to kill bacteria, but at the same time ROS regulate cellular events in the host. However, prolonged generation of ROS has been implicated in damage of DNA, which ultimately could lead to the development of cancer. We studied a molecule known as APE-1 in gastric and intestinal cells, which is activated upon encounter of ROS. Our results show that APE1 limits the production of ROS in cells that form the lining of the gastrointestinal tract. APE1 regulates ROS production by inhibiting activation of the molecule Rac1. Inhibition of ROS production by APE1 occurred after infection of gastric cells with Helicobacter pylori and after Salmonella infection of intestinal cells. These data demonstrate that APE1 inhibits production of ROS in cells that line the inside of the digestive tract.

[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.

Hybrid vs sequential therapy for eradication of Helicobacter pylori in Taiwan: A prospective randomized trial

AIM: To evaluate the efficacy of sequential vs hybrid therapy in patients with Helicobacter pylori (H. pylori) infection.

METHODS: From March 2013 to May 2014, one hundred and seventy-five H. pylori infected patients who had not been treated for H. pylori before were randomized to receive either sequential therapy (rabeprazole 20 mg and amoxicillin 1 g twice daily for 5 d, followed by rabeprazole 20 mg, clarithromycin 500 mg and metronidazole 500 mg twice daily for 5 d) or hybrid therapy (rabeprazole 20 mg and amoxicillin 1 g for 7 d, followed by rabeprazole 20 mg, amoxicillin 1 g, clarithromycin 500 mg and metronidazole 500 mg twice daily for 7 d). H. pylori status was confirmed by positive results of both rapid urease test and histology examination or a positive result of culture. Eradication efficacy was assessed by follow-up endoscopy with rapid urease test and histological examination 8 wk after the end of anti-H. pylori therapy, or ¹³C-urea breath test at least 4 wk after completion of treatment. The primary outcome was H. pylori eradication by intension-to-treat (ITT) and per-protocol (PP) analyses.

RESULTS: One hundred and sixty-seven patients (83 patients in the sequential group and 84 patients in the hybrid group) completed the study. The compliance rates were 97.6% and 97.7% for the two groups, respectively. The eradication rate was 78.2% for the sequential group and 92% for the hybrid group by ITT analysis (P = 0.01). The eradication rate was 81.9% for the sequential group and 96.4% for the hybrid group by PP analysis (P = 0.01). Univariate analysis for the clinical and bacterial factors did not identify any risk factors associated with treatment failure. Severe adverse events were observed in 2.3% of patients in the sequential group and 2.4% of those in the hybrid group.

CONCLUSION: Due to a grade A (> 95%) success rate for H. pylori eradication by PP analysis, similar compliance and adverse events, hybrid therapy seems to be an appropriate eradication regimen in Taiwan.

The role of C1q in recognition of apoptotic epithelial cells and inflammatory cytokine production by phagocytes during Helicobacter pylori infection

Background

Gastric epithelial cells (GECs) undergo apoptosis during H. pylori infection and phagocytes within the mucosa engulf these cells. The recognition and clearance of apoptotic cells is a multifactorial process, enhanced by the presence of various bridging molecules and opsonins which are abundant in serum. However, it is not clear how recognition or clearance may differ in the context of H. pylori infection induced apoptosis. In addition, efferocytosis of sterile apoptotic cells is known to confer anti-inflammatory properties in the engulfing phagocyte, however it is unknown if this is maintained when phagocytes encounter H. pylori-infected cells. Thus, the ability of macrophages to bind and engulf gastric epithelial cells rendered apoptotic by H. pylori infection and the association of these interactions to the modulation of phagocyte inflammatory responses was investigated in the absence and presence of serum with a particular focus on the role of serum protein C1q.

Methods

Control (uninfected) or H. pylori-infected AGS cells were co-cultured with THP-1 macrophages in the presence or absence of serum or serum free conditions + C1q protein (40–80 μg/mL). Binding of AGS cells to THP-1 macrophages was assessed by microscopy and cytokine (IL-6 and TNF-α) release from LPS stimulated THP-1 macrophages was quantified by ELISA.

Results

We show that macrophages bound preferentially to cells undergoing apoptosis subsequent to infection with H. pylori. Binding of apoptotic AGS to THP-1 macrophages was significantly inhibited when studied in the absence of serum and reconstitution of serum-free medium with purified human C1q restored binding of macrophages to apoptotic cells. Co-culture of sterile apoptotic and H. pylori-infected AGS cells both attenuated LPS-stimulated cytokine production by THP-1 macrophages. Further, direct treatment of THP-1 macrophages with C1q attenuated LPS stimulated TNF-α production.

Conclusions

These studies suggest that C1q opsonizes GECs rendered apoptotic by H. pylori. No differences existed in the ability of infected or sterile apoptotic cells to attenuate macrophage cytokine production, however, there may be a direct role for C1q in modulating macrophage inflammatory cytokine production to infectious stimuli.

Electronic supplementary material

The online version of this article (doi:10.1186/s12950-015-0098-8) contains supplementary material, which is available to authorized users.

Role of Inflammatory Monocytes in Vaccine-Induced Reduction of Helicobacter felis Infection

Despite the proven ability of immunization to reduce Helicobacter infection in mouse models, the precise mechanism of protection has remained elusive. In this study, we evaluated the role of inflammatory monocytes in the vaccine-induced reduction of Helicobacter felis infection. We first showed by using flow cytometric analysis that Ly6C(low) major histocompatibility complex class II-positive chemokine receptor type 2 (CCR2)-positive CD64(+) inflammatory monocytes accumulate in the stomach mucosa during the vaccine-induced reduction of H. felis infection. To determine whether inflammatory monocytes played a role in the protection, these cells were depleted with anti-CCR2 depleting antibodies. Indeed, depletion of inflammatory monocytes was associated with an impaired vaccine-induced reduction of H. felis infection on day 5 postinfection. To determine whether inflammatory monocytes had a direct or indirect role, we studied their antimicrobial activities. We observed that inflammatory monocytes produced tumor necrosis factor alpha and inducible nitric oxide synthase (iNOS), two major antimicrobial factors. Lastly, by using a Helicobacter in vitro killing assay, we showed that mouse inflammatory monocytes and activated human monocytes killed H. pylori in an iNOS-dependent manner. Collectively, these data show that inflammatory monocytes play a direct role in the immunization-induced reduction of H. felis infection from the gastric mucosa.

Effect of eradication of Helicobacter pylori on expression levels of FHIT, IL-8 and P73 in gastric mucosa of first-degree relatives of gastric cancer patients

Objectives

Helicobacter pylori (H. pylori) infection plays an important role in the carcinogenesis and development of gastric cancer. Eradication of H. pylori can effectively reduce the risk of gastric cancer, but the underlying mechanisms are not fully understood. This study aimed to investigate the effect of eradication of H. pylori on the expression levels of FHIT, IL-8 and P73 in the gastric mucosa of first-degree relatives of gastric cancer patients.

Methods

One hundred and thirty-two patients with functional dyspepsia having first-degree relatives with gastric cancer were prospectively recruited in this study. Nine patients presented with H. pylori infection and family histories of gastric cancer, 61 with H. pylori infection and without family histories of gastric cancer, 6 without H. pylori infection and with family histories of gastric cancer, and 56 without H. pylori infection and family histories of gastric cancer. The protein and mRNA expression levels of FHIT, IL-8 and P73 in gastric mucosa of the subjects were detected by immunohistochemical staining and polymerase chain reaction, respectively.

Results

Compared with the patients without H. pylori infection and family histories of gastric cancer, both the protein and mRNA levels of FIHT significantly decreased in patients with H. pylori infection and/or family histories of gastric cancer, and both the protein and mRNA levels of IL-8 significantly increased. After eradication of H. pylori, both the protein and mRNA levels of FHIT were significantly higher, and both the protein and mRNA levels of IL-8 were significantly lower. However, H. pylori infection and family histories of gastric cancer had no major effect on P73 expression.

Conclusions

Down-regulation of FHIT and up-regulation of IL-8 may be involved in the pathogenesis of H. pylori infection in the first-degree relatives of gastric cancer patients.

Role of ROS in DNA damage caused by Helicobacter pylori in gastric epithelial cells

AIM: To explore the relationship between the change of reactive oxygen species (ROS) and DNA damage caused by Helicobacter pylori (H. pylori) infection in gastric epithelial cells.

METHODS: H. pylori ACTC43504 (CagA⁺, VacA⁺) infected GES-1 cells were used in this study. Live cell imaging system was used to observe the change of intracellular ROS, and a microplate reader was used to detect intracellular ROS level. Single cell gel electrophoresis comet assay was used to detect DNA damage.

RESULTS: ROS level was proportional to H. pylori concentration, and the ROS level was the highest when the MOI of H. pylori was 300:1. Various concentrations of N-acety-L-cysteine (NAC) could significantly inhibit the generation of ROS caused by H. pylori infection. H. pylori could cause DNA damage. After NAC pretreatment, the values of tail length, comet length, tail moment, and Olive tail moment had a clear downward trend compared with the H. pylori group.

CONCLUSION: H. pylori infection in GES-1 cells increases intracellular ROS level and results in DNA damage. Inhibition of the generation of ROS could reduce DNA damage.

The association between Helicobacter pylori gastritis and lymphoid aggregates, lymphoid follicles and intestinal metaplasia in gastric mucosa of children

AIMS

The aim of the study was to determine the topographic prevalence of lymphoid follicles, lymphoid aggregates, gastric glandular atrophy and intestinal metaplasia among children with chronic abdominal pain. The association between these lesions and age, type of gastritis and Helicobacter pylori density was also assessed.

METHODS

A total of 358 patients (mean age: 10, 18 ± 3, 26 years; male : female ratio: 0.92) with chronic abdominal pain who had upper gastrointestinal endoscopy were included in the study. The endoscopic and histopathological findings were documented. The prevalence of lymphoid follicles, lymphoid aggregates, atrophy and intestinal metaplasia according to the type of gastritis and their relation with H. pylori density were determined.

RESULTS

H. pylori was detected in 214 (59.8%) patients. H. pylori- positive patients were found to be significantly older than H. pylori-negative patients (P < 0.01). The endoscopy revealed that the most common finding observed was antral nodularity in H. pylori-positive patients and normal mucosal appearance in H. pylori-negative patients. Panmucosal gastritis both in the corpus and antrum and the prevalence of lymphoid follicles and lymphoid aggregates were more frequent in the H. pylori-positive group (P < 0.01). None of the patients had atrophy, whereas 11 patients had intestinal metaplasia. Although positive correlation was obtained between lymphoid lesions and H. pylori density, no significant relation was established between intestinal metaplasia, lymphoid lesions and H. pylori density.

CONCLUSION

Lymphoid follicles and lymphoid aggregates in gastric mucosa involving both antrum and corpus significantly correlated with H. pylori infection, H. pylori density and type of gastritis in children.

The role of inflammation in gastric cancer

Gastric cancer, despite its declining incidence rate, is still the second cause of cancer-related death worldwide, killing 750,000 people each year and remaining the second common type of cancer. The best examples of inflammation-associated cancer in human beings may be gastric cancer. Understanding the molecular mechanism of the inflammation in gastric carcinogenesis is important for developing new strategies against gastric cancer.

Epidemiology and pattern of antibiotic resistance in Helicobacter pylori: scenario from Saudi Arabia

Helicobacter pylori is recognized as a major cause of gastritis, peptic ulcer, gastric cancer, and mucosa-associated lymphoma. Infection with this gram-negative microaerophile has been treated using combination of antibiotics and proton pump inhibitors for different gastrointestinal diseases. The most commonly used treatment is triple therapy which consists of administration of a proton pump inhibitor, clarithromycin, and amoxicillin. Many factors contribute to treatment failure, but one of the main reasons is development of bacterial antibiotic resistance. The percent prevalence of antibiotic resistance varies among different countries; it appears to be partly determined by the geographic factors and its ability to undergo frequent homologous recombination. The aim of this paper is to review the prevalence of H. pylori infection, association of clinical outcomes with H. pylori genotypes, and current status of antibiotic resistance in H. pylori in Saudi Arabia. It also discusses the different alternative approaches for the treatment of H. pylori using antibiotics. In addition, association of antibiotic resistance with H. pylori virulent genotypes in Saudi population and its underlying resistance mechanism will also be discussed.

What is the impact of Helicobacter pylori density on the success of eradication therapy: a clinico-histopathological study

BACKGROUND AND OBJECTIVE

To investigate the presence of any possible association between H. pylori density in the stomach and the efficacy of triple (lansoprazole 30 mg b.i.d., clarithromycin 500 mg b.i.d. and amoxicillin 1g b.i.d. for 14 days) and bismuth-containing quadruple (colloidal bismuth subcitrate 300 mg q.i.d., lansoprazole 30 mg b.i.d., tetracycline 500 mg q.i.d. and metronidazole 500 mg t.i.d. for 14 days) eradication therapies.

METHODS

Eighty-five cases with H. pylori infection (proved by rapid urease test and histology) were studied. In each case, the density of H. pylori colonization was graded according to the updated Sydney classification. H. pylori eradication was determined via the (14)C-Urea breath test performed 4 weeks after the end of therapy.

RESULTS

The eradication rate of H. pylori was 50% (30 out of 60) in the triple therapy and 92% (23 of 25) in the quadruple therapy group. In the triple therapy group, the eradication rate of H. pylori decreased as the initial density of H. pylori increased (density of H. pylori: 1, 58.3%; 2, 54.5%; 3, 52.4%; 4, 38.5%; 5, 33.3%). In two cases with eradication failure after quadruple therapy, the grades of bacterial density were 1 and 3.

CONCLUSION

H. pylori density, as assessed by histological grading, may predict the usefulness of triple therapy. The higher the H. pylori density, the less effective triple therapy will be at successful eradication of H. pylori. Quadruple therapy does not seem to be negatively affected by bacterial density.

Genotyping of Helicobacter pylori virulence-associated genes shows high diversity of strains infecting patients in western Venezuela

BACKGROUND

Helicobacter pylori is a major cause of chronic gastritis and an established risk factor for gastric adenocarcinoma. This bacterium also exhibits an extraordinarily high genetic diversity.

METHODS

The genetic diversity of H. pylori strains from Venezuelan patients with chronic gastritis was evaluated by PCR-typing of vacA, cagA, iceA, and babA2 virulence-associated genes using DNA extracted directly from biopsies. The nucleotide sequence and prevalence of size variants of iceA1, iceA2, and babA2 PCR products were introduced in this analysis.

RESULTS

The frequency of vacA s1 was associated (p<0.01) with moderate/severe grades of atrophic gastritis. The cagA, iceA1, iceA2, and babA2 genotypes were found in 70.6%, 66.4%, 33.6%, and 92.3% of strains, respectively. The frequency of iceA2 and its subtype iceA2_D were higher (p<0.015) in cases with moderate/severe granulocytic inflammation. The most prevalent combined genotypes were vacA s1m1/cagA/iceA1/babA2 (26.3%), vacA s2m2/iceA1/babA2 (19.5%), and vacA s1m1/cagA/iceA2/babA2 (18.8%). Sequence analysis of iceA1, iceA2, and babA2 PCR-amplified fragments allowed us to define allelic variants and to increase the number of genotypes detected (from 19 to 62). A phylogenetic tree made with iceA1 sequences showed that the H. pylori strains analyzed here were grouped with those of Western origin.

CONCLUSIONS

Our results show that patients from the western region of Venezuela have an elevated prevalence of infection with H. pylori strains carrying known virulence genotypes with high genetic diversity. This highlights the importance of identifying gene variants for an early detection of virulent genotypes.

Catechins and Sialic Acid Attenuate Helicobacter pylori-Triggered Epithelial Caspase-1 Activity and Eradicate Helicobacter pylori Infection

The inflammasome/caspase-1 signaling pathway in immune cells plays a critical role in bacterial pathogenesis; however, the regulation of this pathway in the gastric epithelium during Helicobacter pylori infection is yet to be elucidated. Here, we investigated the effect of catechins (CAs), sialic acid (SA), or combination of CA and SA (CASA) on H. pylori-induced caspase-1-mediated epithelial damage, as well as H. pylori colonization in vitro (AGS cells) and in vivo (BALB/c mice). Our results indicate that the activity of caspase-1 and the expression of its downstream substrate IL-1β were upregulated in H. pylori-infected AGS cells. In addition, we observed increased oxidative stress, NADPH oxidase gp91phox, CD68, caspase-1/IL-1β, and apoptosis, but decreased autophagy, in the gastric mucosa of H. pylori-infected mice. We have further demonstrated that treatment with CASA led to synergistic anti-H. pylori activity and was more effective than treatment with CA or SA alone. In particular, treatment with CASA for 10 days eradicated H. pylori infection in up to 95% of H. pylori-infected mice. Taken together, we suggest that the pathogenesis of H. pylori involves a gastric epithelial inflammasome/caspase-1 signaling pathway, and our results show that CASA was able to attenuate this pathway and effectively eradicate H. pylori infection.

Helicobacter pylori infection induced gastric cancer; advance in gastric stem cell research and the remaining challenges

Helicobacter pylori infection is the major cause of gastric cancer, which remains an important health care challenge. Recent investigation in gastric stem cell or progenitor cell biology has uncovered valuable information in understanding the gastric gland renewal and maintenance of homeostasis, they also provide clues for further defining the mechanisms by which gastric cancer may originate and progress. Lgr5, Villin-promoter, TFF2-mRNA and Mist have recently been identified as gastric stem/progenitor cell markers; their identification enriched our understanding on the gastric stem cell pathobiology during chronic inflammation and metaplasia. In addition, advance in gastric cancer stem cell markers such as CD44, CD90, CD133, Musashi-1 reveal novel information on tumor cell behavior and disease progression implicated for therapeutics. However, two critical questions remain to be of considerable challenges for future exploration; one is how H. pylori or chronic inflammation affects gastric stem cell or their progenitors, which give rise to mucus-, acid-, pepsinogen-, and hormone-secreting cell lineages. Another one is how bacterial infection or inflammation induces oncogenic transformation and propagates into tumors. Focus on the interactions of H. pylori with gastric stem/progenitor cells and their microenvironment will be instrumental to decipher the initiation and origin of gastric cancer. Future studies in these areas will be critical to uncover molecular mechanisms of chronic inflammation-mediated oncogenic transformation and provide options for cancer prevention and intervention. We review recent progress and discuss future research directions in these important research fields.

Comparison of the Eradication Rate between 1- and 2-Week Bismuth-Containing Quadruple Rescue Therapies for Helicobacter pylori Eradication

Background/Aims

First-line therapies against Helicobacter pylori, including proton pump inhibitors (PPIs) plus two antibiotics, may fail in up to 20% of patients. 'Rescue' therapy is usually needed for patients who failed the first-line treatment. This study evaluated the eradication rate of bismuth-containing quadruple rescue therapy over a 1- or 2-week period.

Methods

We prospectively investigated 169 patients with a persistent H. pylori infection after the first-line triple therapy, which was administered from October 2008 to March 2010. The patients were randomized to receive a 1- or 2-week quadruple rescue therapy (pantoprazole 40 mg b.i.d., tripotassium dicitrate bismuthate 300 mg q.i.d., metronidazole 500 mg t.i.d., and tetracycline 500 mg q.i.d.). After the 'rescue' therapy, the eradication rate, compliance, and adverse events were evaluated.

Results

The 1-week group achieved 83.5% (71/85) and 87.7% (71/81) eradication rates in the intention to treat (ITT) and per-protocol (PP) analyses, respectively. The 2-week group obtained 87.7% (72/84) and 88.9% (72/81) eradication rate in the ITT and PP analyses, respectively. There was no significant difference in the eradication rate, patient compliance or rate of adverse events between the two groups.

Conclusions

One-week bismuth-containing quadruple therapy can be as effective as a 2-week therapy after the failure of the first-line eradication therapy.

Spontaneous autoimmune gastritis and hypochlorhydria are manifest in the ileitis-prone SAMP1/YitFcs mice

SAMP1/YitFcs mice serve as a model of Crohn's disease, and we have used them to assess gastritis. Gastritis was compared in SAMP1/YitFcs, AKR, and C57BL/6 mice by histology, immunohistochemistry, and flow cytometry. Gastric acid secretion was measured in ligated stomachs, while anti-parietal cell antibodies were assayed by immunofluorescence and enzyme-linked immunosorbent spot assay. SAMP1/YitFcs mice display a corpus-dominant, chronic gastritis with multifocal aggregates of mononuclear cells consisting of T and B lymphocytes. Relatively few aggregates were observed elsewhere in the stomach. The infiltrates in the oxyntic mucosa were associated with the loss of parietal cell mass. AKR mice, the founder strain of the SAMP1/YitFcs, also have gastritis, although they do not develop ileitis. Genetic studies using SAMP1/YitFcs-C57BL/6 congenic mice showed that the genetic regions regulating ileitis had comparable effects on gastritis. The majority of the cells in the aggregates expressed the T cell marker CD3 or the B cell marker B220. Adoptive transfer of SAMP1/YitFcs CD4(+) T helper cells, with or without B cells, into immunodeficient recipients induced a pangastritis and duodenitis. SAMP1/YitFcs and AKR mice manifest hypochlorhydria and anti-parietal cell antibodies. These data suggest that common genetic factors controlling gastroenteric disease in SAMP1/YitFcs mice regulate distinct pathogenic mechanisms causing inflammation in separate sites within the digestive tract.