Pathogenesis of Helicobacter pylori infection

Influence of Helicobacter pylori infection on risk of rheumatoid arthritis: a nationwide population-based study

The relationship between Helicobacter pylori infection and rheumatoid arthritis has been investigated, but the results remain controversial. This study aims to determine the association between the two diseases via a 17-year retrospective cohort study. Using the National Health Insurance Research Database, a nationwide population based in Taiwan, we identified 97,533 individuals with H. pylori infection and matched controls between 2000 and 2017 using propensity score matching at a 1:1 ratio. The adjusted hazard ratio of rheumatoid arthritis was determined by multiple Cox regression. The incidence rate of rheumatoid arthritis was 1.28 per 10,000 person-months in the H. pylori cohort, with a higher risk compared to the control group. In the < 30 years old subgroup, the risk was highest, especially in women < 30 years old with H. pylori infection. Patients with < 1 year follow-up showed 1.58 times higher susceptibility to rheumatoid arthritis. Individuals with follow-ups of 1-5 years and over 5 years demonstrated 1.43 and 1.44 times higher risks of rheumatoid arthritis, respectively. Our study showed H. pylori infection was associated with the development of rheumatoid arthritis. Clinicians should note higher risk, especially < 30 years old. More research needed to understand underlying mechanism.

Can neutrophil to lymphocyte ratio be a non-invasive indicator of the presence of duodenal ulcer related Helicobacter pylori in dyspeptic patients?

Background and aims

Neutrophil to lymphocyte ratio (NLR), a novel inflammatory marker, has been shown to increase in various systemic inflammatory conditions. In this way, we want to evaluate the relationship between the presence of H. pylori, duodenal ulcer related H. pylori and NLR in dyspeptic patients.

Material and methods

The patients were divided into three groups after evaluating of the EGD and histopathology results. The groups were determined as follow; Group A: H. pylori positive and DU negative, Group B: H. pylori positive and DU positive, Group C: H. pylori negative and DU negative. Then, groups were compared with each other for demographic features, laboratory tests and NLR.

Results

There were significant differences between groups for NLR when groups compared with each other. Significantly high NLR was seen in group A (H. pylori positive, DU negative) and group B (H. pylori positive, DU positive) when compared with group C (H. pylori negative, DU negative) (respectively p < 0.042, p < 0.001). Significantly higher NLR was determined in the group B when compared with group A and group C (respectively p < 0.021, p < 0.001). The cut-off value for NLR was 2,17 with a specificity of 61% and sensitivity of 66% for group B comparing with Group C (AUC:0,66).

Conclusions

Significantly higher NLR was determined in patients with H. pylori and DU. As a result, NLR may be used as a non-invasive test for documenting the presence of H. pylori and H. pylori related DU.

Anthocyanin-rich black carrot (Daucus carota ssp. sativus var. atrorubens Alef.) and red cabbage (Brassica oleracea) extracts incorporated biosensor for colorimetric detection of Helicobacter pylori with color image processing

In this work, we developed novel colorimetric biosensors consisting of anthocyanin-rich either black carrot (Daucus carota ssp. sativus var. atrorubens Alef.) or red cabbage (Brassica oleracea) extracts for rapid, sensitive, and economic detection of Helicobacter pylori (H. pylori). We comparatively prepared two test solutions as biosensors including anthocyanin-rich black carrot extract (Anth@BCE) and red cabbage extract (Anth@RCE), both of which fixed to pH 2.5 and investigated their colorimetric responses based on electronic structure and electron density of anthocyanins. We successfully used anthocyanin-rich BCE and RCE as natural pH indicators in detection of H. pylori and introduced their advantages like non-toxicity, easy accessibility, and high stability compared to synthetic indicators. The BCE and RCE tests gave the best color change in the presence of 103 CFU/mL (at 60 min) and 104 CFU/mL (at 75 min) H. pylori suspensions prepared in an artificial gastric fluid. The limit of detection was down to 10 CFU/mL for RCE and BCE tests by increasing incubation time (≥ 5 h). We further made an additional study that color differences in the colorimetric responses observed by naked eyes were supported by digital image processing with RGB (Red Green Blue) and Delta-E (ΔE) analysis. It is confirmed that results evaluated by naked eyes and digital image processing are well consistent with each other. These findings proposed that these colorimetric tests can be implemented to pH dependent detection of various microorganisms and can be effectively transferred from laboratory work to clinics in the near future.

Evaluation of Lipid Profile and Inflammatory Marker in Patients with Gastric Helicobacter pylori Infection, Ethiopia

INTRODUCTION

H. pylori are gram-negative, microaerophilic helical-shaped bacteria with multiple flagella and commonly exist in the stomach. This infection may cause significant mucosal inflammation and damage, leading to ulcers in the stomach. It can also affect organ systems external to the gastrointestinal tract. To assess cardiovascular risk factors and to predict cardiovascular disorders, we are evaluating and comparing lipid profile and inflammatory marker between H. pylori-positive and negative patients.

OBJECTIVE

To evaluate and compare lipid profile (TC; TG; LDL; HDL) and inflammatory marker (hs-CRP) in dyspeptic patients with and without H. pylori infection.

METHODS

Comparative cross-sectional study was conducted from September 2020 to January 2021 at Debre Markos Referral Hospital, Debre Markos Health Center, and Hidassie Health Center, Ethiopia. Each of 50 H. pylori-positive and negative dyspeptic patients were studied. The data were checked for completeness and analyzed by SPSS version 25.0 Software. A p-value < 0.05 was considered statistically significant.

RESULTS

Serum mean high-density lipoprotein (HDL) values were 37.54 ± 7.98 mg/dL and 43.12 ± 7.86 mg/dL (p < 0.05) for H. pylori-positive and negative dyspeptic patients, respectively, and median serum high sensitive C reactive protein (hs-CRP) levels were 6.29 mg/L (1.66-41.34) and 3.35 mg/L (0.39-10.01) (p < 0.05) for H. pylori-positive and negative dyspeptic patients, respectively.

CONCLUSION

H. pylori infection significantly alters serum high-density lipoprotein (HDL) and high sensitive C reactive protein (hs-CRP) levels in dyspeptic patients, as a result, increase the potential risk of cardiovascular diseases.

Evaluation of Helicobacter pylori Genotypes in Obese Patients with Gastric Ulcer, Duodenal Ulcer, and Gastric Cancer: An Observational Study

INTRODUCTION

Obesity is a well-known risk factor for a variety of gastrointestinal disorders (GID). Helicobacter pylori is associated with different GID, such as gastric cancer and chronic gastritis. In this study, we investigated the prevalence of dominant genotypes in H. pylori isolated from obese patients diagnosed with gastric ulcer, duodenal ulcer, and gastric cancer.

METHODS

A total of 222 H. pylori-positive samples were collected from patients with obesity. GID and gastric cancer were identified by endoscopy and histopathology, respectively. Three biopsy specimens from the gastric antrum were obtained from each patient for culture tests, histological examination, and identification of vacuolating cytotoxin A (vacA) (vacA s1, vacA s2, vacA m1, vacA m2, vacA s1m1 vacA s1m2, vacA s2m1, and vacA s2m2), cagA, cagE, iceA1, oipA, dupA, and babA2 using polymerase chain reaction.

RESULTS

vacA, cagE, cagA, iceA1, oipA, dupA, and babA2 genes were detected in 222 (100%), 171 (77%), 161 (72.5%), 77 (34.6%), 77 (34.6%), 137 (61%), and 69 (31%) patients with obesity, respectively. Our findings revealed that vacA, iceA1, oipA, and babA2 were significantly associated with a higher risk of GID, while cagE, cagA, and dupA indicated no correlation with the development of GID. Also, in the combination of s- and m-region genotypes, s1m2 (79%) was the most frequently identified genotype in patients with obesity. A significant association was also found between cagA and the presence of vacA genotypes (except for vacA m1 and babA2).

CONCLUSIONS

This study indicated the high prevalence of different virulence genes in H. pylori isolated from obese patients and supported the significant role of H. pylori in the development of GID.

Helicobacter pylori infection and susceptibility to cardiac syndrome X: A systematic review and meta-analysis

BACKGROUND

Cardiac syndrome X (CSX) is characterized by persistent angina with normal coronary arteries. Several pathophysiologic mechanisms have been introduced, particularly Helicobacter pylori (H. pylori) infection.

AIM

To investigate the association between H. pylori infection and CSX.

METHODS

All studies related to H. pylori infection and CSX were evaluated by comprehensive searches of global databases such as ISI Web of Knowledge, PubMed, Scopus, EMBASE, and Google scholar. Statistical analyses of selected articles were evaluated based on the summary odds ratio (OR). Finally, heterogeneity and publication bias were estimated using the I² statistic and Cochrane Q-test as well as Begg’s and Egger’s tests.

RESULTS

A total of 11 studies met our inclusion criteria and 1435 patients (63% female, and 37% male) were reviewed. A significant association was observed between female patients and this syndrome (P = 0.02). Our results showed a positive association between infection with this pathogen and presence of CSX (OR: 5.65; 95% confidence interval [CI]: 4.17-7.64; I²: 82.20). However, no significant association was observed with cagA-positive H. pylori strains and this syndrome (OR: 0.97; 0.56-1.70 with 95%CI). Given the heterogeneity and publication bias, the results need to confirmed by further prospective investigation.

CONCLUSION

Based on our results, H. pylori infection is associated with an increased risk of CSX. This bacterium appears to play a major role in the pathogenesis of CXS by inducing persistent inflammation.

CagE, cagA and cagA 3' region polymorphism of Helicobacter pylori and their association with the intra-gastric diseases in Moroccan population

Helicobacter pylori infection is the most important etiological factor in gastroduodenal diseases development. Its evolution is influenced by several factors, including bacterial virulence genes such as cagA and cagE. This work aimed to evaluate the predictive value of cagE alone and in combination with cagA and CagA-EPIYA-C motifs number as a marker of the infection evolution. A total of 823 H. pylori DNA extracted from biopsies of consenting patients suffering from gastritis, peptic ulcer, or gastric cancer. The cagE, cagA status and cagA 3' region polymorphism were determined by PCR. The analysis shows that the risk of duodenal ulcer is 1.97-fold higher (CI = 1.18-3.30) in patients infected by strains cagA+/cagE+. And the risk of gastric cancer is 5.19-fold higher (CI = 1.18-22.70) in patients harboring strains cagE+/2EPIYA-C. The results suggest that cagE in combination with cagA-EPIYA-C motifs number can be used as predictive biomarker of H. pylori infection evolution.

Association of Helicobacter pylori babA2 gene and gastric cancer risk: a meta-analysis

Background

The association of Helicobacter pylori (H. pylori) babA2 gene with gastric cancer (GC) was reported by several studies, but results were inconsistent. This meta-analysis was performed to investigate the relationship between H. pylori babA2 gene and GC risk.

Methods

Case-control studies involving the association between H. pylori babA2 gene and GC risk were systematically identified from PubMed databases. A meta-analysis was used to pool studies and to estimate odds ratios (ORs) with 95% confidence intervals (CIs) of H. pylori babA2 gene associated with GC risk.

Results

Twenty studies were identified with a total of 1289 GC cases and 1081 controls. H. pylori babA2 gene was associated with an increased risk of GC by 2.05 fold (95% CI, 1.30–3.24, P = 0.002). In subgroup analysis, we found that H. pylori babA2 gene was significantly associated with GC risk in Asian population (OR = 2.63, 95% CI: 1.36–5.09 P = 0.004) but not in South American population (OR = 1.35, 95% CI: 0.69–2.64, P = 0.379).

Conclusions

This meta-analysis indicates that H. pylori babA2 gene may be associated with increased risk of GC, especially in Asian population.

Genetic variation in the cag pathogenicity island of Helicobacter pylori strains detected from gastroduodenal patients in Thailand

There is a lack of evidence of genetic variation in the Helicobacter pylori cag-PAI in Thailand, a region with the low incidence of gastric cancer. To clarify this issue, variation in the H. pylori cag-PAI in strains detected in Thailand was characterized and simultaneously compared with strains isolated from a high-risk population in Korea. The presence of ten gene clusters within cag-PAI (cagA, cagE, cagG, cagH, cagL, cagM, cagT, orf13, virB11, and orf10) and IS605 was characterized in H. pylori strains detected from these two countries. The cagA genotypes and EPIYA motifs were analyzed by DNA sequencing. The overall proportion of the ten cag-PAI genes that were detected ranged between 66 and 79%; additionally, approximately 48% of the strains from Thai patients contained an intact cag-PAI structure, while a significantly higher proportion (80%) of the strains from Korean patients had an intact cag-PAI. A significantly higher proportion of IS605 was detected in strains from Thai patients (55%). Analysis of cagA genotypes and EPIYA motifs revealed a higher frequency of Western-type cagA in Thai patients (87%) relative to Korean patients (8%) who were predominately associated with the East Asian-type cagA (92%). Variations in the Western-type cagA in the Thai population, such as EPIYA-BC patterns and EPIYA-like sequences (EPIYT), were mainly detected as compared with the Korean population (p < 0.05). In summary, H. pylori strains that colonize the Thai population tend to be associated with low virulence due to distinctive cag-PAI variation, which may partially explain the Asian paradox phenomenon in Thailand.

Mechanisms of the Epithelial-Mesenchymal Transition and Tumor Microenvironment in Helicobacter pylori-Induced Gastric Cancer

Helicobacter pylori (H. pylori) is one of the most common human pathogens, affecting half of the world’s population. Approximately 20% of the infected patients develop gastric ulcers or neoplastic changes in the gastric stroma. An infection also leads to the progression of epithelial–mesenchymal transition within gastric tissue, increasing the probability of gastric cancer development. This paper aims to review the role of H. pylori and its virulence factors in epithelial–mesenchymal transition associated with malignant transformation within the gastric stroma. The reviewed factors included: CagA (cytotoxin-associated gene A) along with induction of cancer stem-cell properties and interaction with YAP (Yes-associated protein pathway), tumor necrosis factor α-inducing protein, Lpp20 lipoprotein, Afadin protein, penicillin-binding protein 1A, microRNA-29a-3p, programmed cell death protein 4, lysosomal-associated protein transmembrane 4β, cancer-associated fibroblasts, heparin-binding epidermal growth factor (HB-EGF), matrix metalloproteinase-7 (MMP-7), and cancer stem cells (CSCs). The review summarizes the most recent findings, providing insight into potential molecular targets and new treatment strategies for gastric cancer.

Helicobacter pylori And Duodenal Ulcer: Systematic Review Of Controversies In Causation

Background

There are controversies on the causal role of H. pylori in duodenal ulceration. Helicobacter pylori are curved gram-negative microaerophilic bacteria found at the layer of gastric mucous or adherent to the epithelial lining of the stomach. It’s a public health significance bacteria starting from discovery, and the prevalence and severity of the infection varies considerably among populations. H. pylori are a risk for various diseases, while the extent of host response like gastric inflammation and the amount of acid secretion by parietal cells affects the outcome of infection.

Method

Relevant literature were searched from databases such as Google Scholar, PubMed, Hinari, Web of Science, Scopus, and Science Direct.

Result

The review evidence supports a strong causal relation between H. pylori infection and duodenal ulcer, as patients are more likely to be infected by virulent strains which later cause duodenal ulceration. Thus, eradication of H. pylori infection decreases the incidence of duodenal ulcers, and prevents its recurrence by reducing both basal gastrin release and acid secretion without affecting parietal cell sensitivity. On the other hand, some studies show that H. pylori infection is not associated with the development of duodenal ulcers and such a lack of association revealed that duodenal ulceration has different pathogenesis.

Conclusion

Despite controversies observed in the causal role of H. pylori to duodenal ulceration by various studies, Hill criteria of causation proved the presence of a causal relation between H. pylori infection and duodenal ulcers. Other factors are also responsible for the development of duodenal ulcers and such factors are responsible for the differences in the prevalence of the diseases.

Relationship between Helicobacter pylori cytotoxin-associated gene A protein with clinical outcomes in patients with rheumatoid arthritis

INTRODUCTION

The Helicobacter pylori(H. pylori) infection leads to intensification of symptoms and calenture of autoimmune diseases. This study aimed to evaluate the relationship between H. pylori infection and clinical outcomes in rheumatoid arthritis (RA) patients.

METHODOLOGY

This study was performed on 100 RA patients. Blood samples were collected for measuring Anti-H. pylori IgG antibodies and cytotoxin-associated gene A (CagA) protein. Fresh fecal samples were also collected and the fecal H. pylori antigen was extracted. Clinical condition as well as severity and type of RA symptoms in both groups of H. pylori positive and H. pylori negative were also compared.

RESULTS

Serum levels of rheumatoid factor (RF), ESR, CRP, anti-cyclic citrullinated peptide (Anti-CCP), and anti-mutated citrullinated vimentin (Anti-MCV) were significantly higher in H. pylori positive patients than in H. pylori negative patients (P < 0.05). Serum RF, ESR, CRP and Anti-MCV levels were significantly higher in CagA positive patients than in CagA negative patients (P < 0.05). There were no significant differences in DAS-28 scores between H. pylori positive and H. pylori negative patients (P = 0.064) as well as between patients with positive and negative fecal H. pylori antigen (P = 0.237). However, DAS-28 score was significantly higher in CagA positive patients than in CagA negative patients (P < 0.001). Furthermore, mean VAS score was significantly higher in H. pylori positive patients (P = 0.031) and CagA positive patients (P = 0.004); however, there were no significant differences in VAS scores between patients with positive and negative fecal H. pylori antigen (P = 0.310).

CONCLUSION

Follow-up and examination of RA patients in terms of infection with serum and fecal H. pylori organism and CagA seems necessary that will contribute to better and further control and treatment of the patients.

Detection of intracellular Helicobacter pylori in Candida. SPP from neonate oral swabs

SUMMARY BACKGROUND: There is evidence of detection of Helicobacter pylori (H. pylori) in the stool of newborns and in the yeast that colonizes the oral cavity of this age group. However, there is a lack of research to confirm it. This study proposes to determine the existence of the bacteria at an early age, specifically in newborns. OBJECTIVE: To identify intracellular H. pylori in oral yeasts and to detect antigens of the bacteria in newborn stools. METHODOLOGY: Cross-sectional and descriptive study. Samples were obtained from infants (oral swab and meconium). Identification of yeast species was performed using the following techniques: CHROMagar Candida, Germinal Tube Test and API Candida Identification System, then the yeasts were observed by light microscopy and fluorescence. Detection of H. pylori antigen in meconium and PCR were performed to amplify specific genes of the bacterium (rRNA16S, cagA, vacA s1a, vacA s1b, vacA s2, vacA m1, vacA m2 and dupA). RESULTS: Intracellular H. pylori was detected in yeast of the species Candida glabrata (C. glabrata) isolated from an oral swab of a newborn. CONCLUSION: The results of this study evidenced the existence of intracellular H. pylori in newborns.

Diversification of the vacAs1m1 and vacAs2m2 Strains of Helicobacter pylori in Meriones unguiculatus

The bacterium Helicobacter pylori exhibits great genetic diversity, and the pathogenic roles of its virulence factors have been widely studied. However, the evolutionary dynamics of H. pylori strains during stomach colonization are not well-characterized. Here, we analyzed the microevolutionary dynamics of the toxigenic strain vacAs1m1, the non-toxigenic strain vacAs2m2, and a combination of both strains in an animal model over time. Meriones unguiculatus were inoculated with the following bacteria: group 1-toxigenic strain vacAs1m1/cagA+/cagE+/babA2+; ST181, group 2-non-toxigenic strain vacAs2m2/cagA+/cagE+/babA2+; ST2901, and group 3-both strains. The gerbils were euthanized at different time points (3, 6, 12, and 18 months). In group 1, genetic alterations were observed at 6 and 12 months. With the combination of both strains, group 3 also exhibited genetic alterations at 3 and 18 months; moreover, a chimera, vacA m1-m2, was detected. Additionally, four new sequence types (STs) were reported in the PubMLST database for H. pylori. Synonymous and non-synonymous mutations were analyzed and associated with alterations in amino acids. Microevolutionary analysis of the STs (PHYLOViZ) identified in each group revealed many mutational changes in the toxigenic (vacAs1m1) and non-toxigenic (vacAs2m2) strains. Phylogenetic assessments (eBURST) did not reveal clonal complexes. Our findings indicate that the toxigenic strain, vacAs1m1, and a combination of toxigenic and non-toxigenic strains acquired genetic material by recombination. The allelic combination, vacAs2m1, displayed the best adaptation in the animal model over time, and a chimera, m1-m2, was also identified, which confirmed previous reports.

[Maternal infection due to Helicobacter pylori does not increase the risk of the infection in the first trimester of the life of their infants]

INTRODUCTION

H. pylori infection is acquired early in childhood. However, there is little information available regarding the role of breastfeeding and neonatal acquisition of the infection.

OBJECTIVE

To evaluate factors affecting the acquisition of H. pylori in newborns and infants from infected mothers.

PATIENTS AND METHOD

Consecutive mothers and their newborns were recruited into the study from the maternity unit, immediately after delivery. After signing informed consent, one stool sample from the mother was obtained before hospital discharge. Three stool samples of the newborns were then collected at home at 15, 60, and 90 days of life, for the detection of H. pylori antigen (Monoclonal HpSAg, sensitivity 94% and specificity 97%). The socio-epidemiological and biomedical variables were also analysed using a questionnaire.

RESULTS

A total of 32 mother-child pairs (64 subjects) were enrolled. The mean maternal age was 30.1±5.1 years, with 53% vaginal delivery, and 85% exclusively breastfed. There were 13 (40%) infected mothers. No H. pylori infection was detected in newborns and infants up to 3 months of follow-up. No significant differences were found in socioeconomic level between infected versus non-infected mothers (both groups mostly in the very high socioeconomic category: 28% and 32%, respectively, P=.15) and in the number of family members between infected versus non-infected mothers (3.8±0.8 vs 4.2±1.8 persons, P=.18).

CONCLUSION

Despite having a significant percentage of H. pylori-infected mothers, no newborn was infected at the third month of life. The protective role of breastfeeding cannot be ruled out.

Helicobacter pylori hopQ alleles (type I and II) in gastric cancer

The Helicobacter pylori (H. pylori) outer membrane protein (HopQ) of is one of the proteins involved in bacterial adherence to gastric mucosa and has been suggested to have a role in the virulence of H. pylori. The aim of the present study was to determine the association between H. pylori virulence types I and II hopQ genotypes and patients with different gastrointestinal diseases. A polymerase chain reaction-based assay was used to determine the presence of type I and type II hopQ genes in 88 H. pylori strains isolated from H. pylori-infected patients. Of the total 88 H. pylori isolates, type I and type II hopQ alleles were detected in 52 (59.1%) and 36 (40.9%), respectively. A significant association was found between type I hopQ gene and gastric cancer [odds ratio, 2.3; 95% confidence interval (CI), 1.3-4.1] and gastric ulcers (odds ratio, 2.5; 95% CI, 1.4-4.3). A significant association was also identified between the type II hopQ gene and gastric cancer (odds ratio, 2.4; 95% CI, 1.1-3.0). The association between hopQ type I and hopQ type II genotypes and clinical status suggest that these genes may be helpful in the universal prediction of specific disease risks.

Polymorphisms of the IL-6, IL-8 and IL-10 genes and the risk of gastric pathology in patients infected with Helicobacter pylori

BACKGROUND/PURPOSE

Helicobacter pylori-induced gastric mucosal inflammation is mediated by proinflammatory and anti-inflammatory cytokines. Polymorphisms in genes that code cytokines influence cytokine secretion levels and appear to contribute to the risk of gastric diseases. In this sense, we performed this study to identify the polymorphisms in the IL-6, IL-8, and IL-10 genes and their associations with H. pylori infection and gastric pathologies.

METHODS

Gastric biopsy samples of 151 patients infected with H. pylori and 76 uninfected individuals were used. Helicobacter pylori infection was diagnosed by histological examination and the detection of the ureA and glmM genes. The polymorphisms in the IL-6 (at position -174), IL-8 (at position -251), and IL-10 (at position -819) were detected by polymerase chain reaction-restriction fragment length polymorphism.

RESULTS

Among the genetic polymorphisms studied, we observed that only the presence of the A allele at position -251 of the IL-8 gene was significantly associated with H. pylori infection. In addition, patient carriers of the A/A genotype at position -251 of the IL-8 gene and carriers of the T allele at position -819 of the IL-10 gene had an increased risk of peptic ulcer disease in the presence of H. pylori infection. We did not find a correlation between polymorphisms in the IL-6, IL-8, and IL-10 genes and a higher risk of gastric carcinoma.

CONCLUSION

We demonstrated that polymorphisms in the IL-8 gene was significantly associated with H. pylori infection. Furthermore, polymorphisms in the IL-8 and IL-10 genes were associated with an enhanced risk of peptic ulcer disease in H. pylori-positive patients.

Physical stress and bacterial colonization

Bacterial surface colonizers are subject to a variety of physical stresses. During the colonization of human epithelia such as on the skin or the intestinal mucosa, bacteria mainly have to withstand the mechanical stress of being removed by fluid flow, scraping, or epithelial turnover. To that end, they express a series of molecules to establish firm attachment to the epithelial surface, such as fibrillar protrusions (pili) and surface-anchored proteins that bind to human matrix proteins. In addition, some bacteria--in particular gut and urinary tract pathogens--use internalization by epithelial cells and other methods such as directed inhibition of epithelial turnover to ascertain continued association with the epithelial layer. Furthermore, many bacteria produce multilayered agglomerations called biofilms with a sticky extracellular matrix, providing additional protection from removal. This review will give an overview over the mechanisms human bacterial colonizers have to withstand physical stresses with a focus on bacterial adhesion.

Role of Helicobacter pylori infection in autoimmune systemic rheumatic diseases

The relationship between infection and autoimmunity has been increasingly defined over the last 20 years. The systemic rheumatic diseases are characterized by dysregulation of the immune system resulting in a loss of tolerance to self-antigen. The exact etiology for the majority of these diseases is unknown; however, a complex combination of host and environmental factors are believed to play a pivotal role. Helicobacter pylori (H. pylori) is one of the most widely studied infectious agents proposed as agents triggering autoimmune response. The persistent presence of H. pylori in the gastric mucosa results in chronic immune system activation with ongoing cytokine signaling, infiltration of gastric mucosa by neutrophils, macrophages, lymphocytes, as well as production of antibodies and effector T-cells. Various mechanisms have been proposed in an attempt to explain the extra-intestinal manifestations of H. pylori infections. These include: molecular mimicry, endothelial cell damage, superantigens and microchimerism. I performed a systematic literature review using the keywords “rheumatoid arthritis”, “Sjögren’s syndrome”, “systemic sclerosis”, “systemic lupus erythematosus”, “Helicobacter pylori” and “pathogenesis”. A systematic literature search was carried out in MEDLINE; EMBASE; Cochrane Library and ACR/EULAR meeting abstracts. In systemic rheumatic diseases H. pylori infection prevalence alone should not be expected to provide sufficient evidence for or against a pathologic role in the disease. In this article I review studies examining the potential involvement of H. pylori infection in autoimmune systemic rheumatic diseases. Further studies of the immunological response to H. pylori and its role in the pathogenesis of systemic rheumatic diseases are warranted.

Helicobacter pylori infection activates Src homology-2 domain-containing phosphatase 2 to suppress IFN-γ signaling

Helicobacter pylori infection not only induces gastric inflammation but also increases the risk of gastric tumorigenesis. IFN-γ has antimicrobial effects; however, H. pylori infection elevates IFN-γ-mediated gastric inflammation and may suppress IFN-γ signaling as a strategy to avoid immune destruction through an as-yet-unknown mechanism. This study was aimed at investigating the mechanism of H. pylori-induced IFN-γ resistance. Postinfection of viable H. pylori decreased IFN-γ-activated signal transducers and activators of transcription 1 and IFN regulatory factor 1 not only in human gastric epithelial MKN45 and AZ-521 but also in human monocytic U937 cells. H. pylori caused an increase in the C-terminal tyrosine phosphorylation of Src homology-2 domain-containing phosphatase (SHP) 2. Pharmacologically and genetically inhibiting SHP2 reversed H. pylori-induced IFN-γ resistance. In contrast to a clinically isolated H. pylori strain HP238, the cytotoxin-associated gene A (CagA) isogenic mutant strain HP238(CagAm) failed to induce IFN-γ resistance, indicating that CagA regulates this effect. Notably, HP238 and HP238(CagAm) differently caused SHP2 phosphorylation; however, imaging and biochemical analyses demonstrated CagA-mediated membrane-associated binding with phosphorylated SHP2. CagA-independent generation of reactive oxygen species (ROS) contributed to H. pylori-induced SHP2 phosphorylation; however, ROS/SHP2 mediated IFN-γ resistance in a CagA-regulated manner. This finding not only provides an alternative mechanism for how CagA and ROS coregulate SHP2 activation but may also explain their roles in H. pylori-induced IFN-γ resistance.

Virulence Factors of Helicobacter pylori: A Review

Helicobacter pylori is a spiral-shaped Gram-negative bacterium that colonizes the human stomach and can establish a long-term infection of the gastric mucosa, a condition that affects the relative risk of developing various clinical disorders of the upper gastrointestinal tract, such as chronic gastritis, peptic ulcer disease, mucosa-associated lymphoid tissue (MALT) lymphoma, and gastric adenocarcinoma. H. pylori presents a high-level of genetic diversity, which can be an important factor in its adaptation to the host stomach and also for the clinical outcome of infection. There are important H. pylori virulence factors that, along with host characteristics and the external environment, have been associated with the different occurrences of diseases. This review is aimed to analyzing and summarizing the main of them and possible associations with the clinical outcome.

Enhanced expression of activation-induced cytidine deaminase in human gastric mucosa infected by Helicobacter pylori and its decrease following eradication

BACKGROUND

Recent studies have shown important roles for activation-induced cytidine deaminase (AID), an intrinsic genome mutator, in H. pylori-associated gastric cancer development. Here, we evaluated the relationship between H. pylori-induced gastritis and AID expression from human biopsy specimens.

METHODS

In 109 patients with dyspeptic symptoms who had undergone endoscopy and received biopsy of the antrum, angulus, and corpus, H. pylori infection was diagnosed by serologic test, (13)C urea breath test, and histological examination. Histological scores of H. pylori, neutrophils, mononuclear cells, atrophy, and intestinal metaplasia (IM) were assessed using the updated Sydney system (USS). Immunohistochemical AID expression of the biopsy specimens was scored.

RESULTS

Sixty of 109 (55.0 %) patients were positive for H. pylori and eradication was successful in 48 patients. AID expression in H. pylori-infected mucosa was significantly higher (p < 0.01) than in non-infected mucosa. AID expression was highest in the antrum and was significantly (p < 0.01) reduced toward the proximal portion of the stomach. For USS, multivariate analysis using linear regression revealed that mononuclear cell infiltration (p < 0.01) and IM (p < 0.05) correlated independently with AID expression. After eradication of H. pylori, AID expression was significantly decreased (p < 0.01), but was still higher than that in H. pylori-negative patients in all sites of the stomach.

CONCLUSIONS

AID expression is elevated in H. pylori-positive patients and is reduced following H. pylori eradication. Moreover, AID expression is highest in the antrum and correlated with severity of chronic inflammation and IM, suggesting an important role for AID in gastric cancer development through gastritis.

Differential proteomics of Helicobacter pylori associated with autoimmune atrophic gastritis

Atrophic autoimmune gastritis (AAG) is a condition of chronic inflammation and atrophy of stomach mucosa, for which development can be partially triggered by the bacterial pathogen Helicobacter pylori (HP). HP can cause a variety of gastric diseases, such as duodenal ulcer (DU) or gastric cancer (GC). In this study, a comparative proteomic approach was used by two-dimensional fluorescence difference gel electrophoresis (DIGE) to identify differentially expressed proteins of HP strains isolated from patients with AAG, to identify markers of HP strain associated with AAG. Proteome profiles of HP isolated from GC or DU were used as a reference to compare proteomic levels. Proteomics analyses revealed 27 differentially expressed spots in AAG-associated HP in comparison with GC, whereas only 9 differential spots were found in AAG-associated HP profiles compared with DU. Proteins were identified after matrix-assisted laser desorption ionization (MALDI)-TOF and peptide mass fingerprinting. Some AAG-HP differential proteins were common between DU- and GC-HP (peroxiredoxin, heat shock protein 70 [HSP70], adenosine 5'-triphosphate [ATP] synthase subunit α, flagellin A). Our results presented here may suggest that comparative proteomes of HP isolated from AAG and DU share more common protein expression than GC and provide subsets of putative AAG-specific upregulated or downregulated proteins that could be proposed as putative markers of AAG-associated HP. Other comparative studies by two-dimensional maps integrated with functional genomics of candidate proteins will undoubtedly contribute to better decipher the biology of AAG-associated HP strains.

High Prevalence of Helicobacter pylori hopQ II Genotype Isolated from Iranian Patients with Gastroduodenal Disorders

Helicobacter pylori plays an important role in the pathogenesis of chronic gastritis, peptic ulceration, and noncardia gastric cancer. Several putative virulence factors for H. pylori have been identified including vacA, babA, and iceA. HopQ is one of the outer membrane proteins involved in bacterial adherence to gastric mucosa and has been suggested to also play a role in the virulence of H. pylori. Due to the substantial geographic differences in the prevalence of H. pylori virulence factors reported, the main purpose of the current study was to investigate the association between different H. pylori virulence hopQ alleles (types I and II) and patients with gastroduodenal disorders. The presence of H. pylori and hopQ alleles in gastric biopsy specimens was identified by specific PCR assays. H. pylori type II hopQ was found to be significantly associated with gastric cancer patients (odds ratio: 3.47, 95% CI: 1.56–5.89). Information about the prevalence of H. pylori hopQ type II can be used for determining the high-risk diseases type which is actually colonized by H. pylori hopQ type II positive strains. The presence of H. pylori hopQ type II should be investigated in different geographical regions as confirmatory findings may provide a definite biomarker attributed to the pathogenesis of certain severe digestive diseases.

High correlation of babA 2-positive strains of Helicobacter pylori with the presence of gastric cancer

Helicobacter pylori (H. pylori) is a Gram-negative bacterium that is well known in the involvement of chronic inflammation in the gastric mucosa of the human stomach. Several studies have investigated the possible role of H. pylori presence in different gastroduodenal disorders with conflicting results. This study aimed to further investigate such a field. Helicobacter pylori strains were cultured from 160 patients (mean age of 42 years; range 15-75; 90 were male, and 70 were female) [40 gastric cancer (GC), 55 duodenal ulcer (DU) and 65 non-ulcer dyspepsia (NUD)]. In this study, allelic variants of iceA 1, iceA 2 and babA 2 were identified by polymerase chain reaction. The overall prevalence of babA 2 gene was 40.6% (65/160). The prevalence of babA 2 gene was 95% with gastric cancer, 18.1% with duodenal ulcer and 26.1% with non ulcer dyspepsia, respectively. The prevalence of babA 2 in GC patients was significantly higher as compared to either NUD or UD patients (P = 0.0004), while no statistical significance was found between the latter two patient groups. Our study finds that babA 2 and iceA 1 genes are more prevalent in GC compared to either NUD or DU patients in Iran.

Higher serum levels of rheumatoid factor and anti-nuclear antibodies in helicobacter pylori-infected peptic ulcer patients

OBJECTIVES

H. pylori infection has been associated with some autoimmune disorders. The aim of this study was to evaluate the serum concentrations of rheumatoid factor and anti-nuclear antibodies in H. pylori-infected peptic ulcer patients, H. pylori-infected asymptomatic carriers and a healthy control group.

METHODS

A Total of 100 H. pylori-infected peptic ulcer patients, 65 asymptomatic carriers and 30 healthy H. pylori-negative subjects (as a control group) were enrolled into study. Serum samples of participants tested for the levels of rheumatoid factor and anti-nuclear antibodies by use of ELISA.

RESULTS

The mean serum levels of rheumatoid factor and anti-nuclear antibodies in peptic ulcer group was significantly higher in comparison to the control group (p<0.05). Although, the mean serum levels of rheumatoid factor and anti-nuclear antibodies in the asymptomatic carriers group was higher than those in the control group, the difference was not statistically significant. No significant differences were observed between peptic ulcer patients and asymptomatic carriers groups regarding the mean serum levels of rheumatoid factor and anti-nuclear antibodies. The mean serum levels of rheumatoid factor in men with peptic ulcer was significantly higher compared to the group of healthy men (p<0.05). Although in female of peptic ulcer patients or asymptomatic carriers groups, the mean serum levels of rheumatoid factor was higher than that in healthy women, but the differences were not statistically significant. Also, no significant differences were observed between men and women with peptic ulcer, asymptomatic carriers control groups based on the serum levels of anti-nuclear antibodies.

CONCLUSION

The results showed higher serum levels of rheumatoid factor and anti-nuclear antibodies in H. pylori-infected patients with peptic ulcer disease which represent the H. pylori-related immune disturbance in these patients. Additional follow-up studies are necessary to clarify the clinical significance of these autoantibodies in patients with H. pylori infection.

Targeted identification of glycosylated proteins in the gastric pathogen Helicobacter pylori (Hp)

Virulence of the gastric pathogen Helicobacter pylori (Hp) is directly linked to the pathogen's ability to glycosylate proteins; for example, Hp flagellin proteins are heavily glycosylated with the unusual nine-carbon sugar pseudaminic acid, and this modification is absolutely essential for Hp to synthesize functional flagella and colonize the host's stomach. Although Hp's glycans are linked to pathogenesis, Hp's glycome remains poorly understood; only the two flagellin glycoproteins have been firmly characterized in Hp. Evidence from our laboratory suggests that Hp synthesizes a large number of as-yet unidentified glycoproteins. Here we set out to discover Hp's glycoproteins by coupling glycan metabolic labeling with mass spectrometry analysis. An assessment of the subcellular distribution of azide-labeled proteins by Western blot analysis indicated that glycoproteins are present throughout Hp and may therefore serve diverse functions. To identify these species, Hp's azide-labeled glycoproteins were tagged via Staudinger ligation, enriched by tandem affinity chromatography, and analyzed by multidimensional protein identification technology. Direct comparison of enriched azide-labeled glycoproteins with a mock-enriched control by both SDS-PAGE and mass spectrometry-based analyses confirmed the selective enrichment of azide-labeled glycoproteins. We identified 125 candidate glycoproteins with diverse biological functions, including those linked with pathogenesis. Mass spectrometry analyses of enriched azide-labeled glycoproteins before and after cleavage of O-linked glycans revealed the presence of Staudinger ligation-glycan adducts in samples only after beta-elimination, confirming the synthesis of O-linked glycoproteins in Hp. Finally, the secreted colonization factors urease alpha and urease beta were biochemically validated as glycosylated proteins via Western blot analysis as well as by mass spectrometry analysis of cleaved glycan products. These data set the stage for the development of glycosylation-based therapeutic strategies, such as new vaccines based on natively glycosylated Hp proteins, to eradicate Hp infection. Broadly, this report validates metabolic labeling as an effective and efficient approach for the identification of bacterial glycoproteins.

A dominant CD4(+) T-cell response to Helicobacter pylori reduces risk for gastric disease in humans

BACKGROUND & AIMS

Immunodominance is an important feature of antiviral, antitumor, and antibacterial cellular immune responses, but it is not well demonstrated in the immune responses against Helicobacter pylori. Antigen-specific CD4(+) T cells protect mice against infection with H pylori. We investigated the immunodominant CD4(+) T-cell response to neuraminyllactose-binding hemagglutinin (HpaA), which is a conserved, H pylori-specific colonization factor that is being investigated as an antigen for vaccination strategies.

METHODS

HpaA-specific CD4(+) T cells were expanded with autologous peripheral blood mononuclear cells that had been incubated with recombinant HpaA and characterized using overlapping synthetic peptides. We compared the percentage of CD4(+) T cells with specificity for HpaA(88-100), restricted to HLA-DRB1*1501, among 59 H pylori-infected subjects with different gastric diseases.

RESULTS

We identified and characterized several immunodominant CD4(+) T-cell epitopes derived from HpaA. The immunodominant CD4(+) T-cell responses specific to HpaA(88-100) were observed in most H pylori-infected individuals who expressed HLA-DRB1*1501 and were significantly more abundant in patients with less severe diseases (P < .05).

CONCLUSIONS

The HLA-DRB1*1501-restricted immunodominant CD4(+) T-cell response to HpaA(88-100) is associated with reduced risk of severe gastric diseases. Further study of these and other immunodominant CD4(+) T-cell responses to H pylori will provide insight into mechanisms of protective immunity and aid in vaccine design.

Low frequency of cagA-positive Helicobacter pylori strains isolated from Iranian patients with MALT lymphoma

Helicobacter pylori is predominantly involved in the etiology of digestive diseases. The aim of our study is to determine the relationship of cagA frequency with less investigated gastroduodenal disorders such as MALT (mucosal associated lymphoid tissue) lymphoma and gastric cancer. One hundred-twenty eight H. pylori-positive patients including: gastritis (n = 74), gastric cancer (n = 26) and MALT lymphoma (n = 28) were entered in our study. Antral biopsy specimen transport, bacterial culture and cagA detection were performed based on standard protocols. In brief, biopsies from positive H. pylori patients were investigated for presence of cagA gene by polymerase chain reactions (PCR) method. Of 128 consecutive Iranian patients with gastroduodenal disorders examined in our study, we identified 84 (65.6%) cagA-positive strains. However, six patients were excluded because of negative culture for identification of H. pylori. Prevalence of cagA in each categorized groups are following: 63/74 (85.1%) of gastritis patients, 16/28 (57.1%) and 5/26 gastric cancer (19.2%) of MALT lymphoma, respectively. Current findings reveal that the presence of cagA is not a reliable marker for prediction of digestive disorders caused by H. pylori infection. All our patients with gastric cancer were diagnosed as adenocarcinoma. The low rate of cagA among gastric cancer and MALT lymphoma groups was not statistically significant, possibly due to the small number of patients enrolled in the study. We suggest that a study with a high number of patients is needed for making more definitive assessment of the correlation between cagA-positive H. pylori and gastric cancer and MALT lymphoma.

Identification of two novel immunodominant UreB CD4(+) T cell epitopes in Helicobacter pylori infected subjects

An epitope-based vaccine is a promising option for treating Helicobacter pylori (H. pylori) infection. Epitope mapping is the first step in designing an epitope-based vaccine. A pivotal role of CD4(+) T cells in protection against H. pylori has been accepted, but few Th epitopes have been identified. In this study, two novel UreB CD4(+) T cell epitopes were identified using PBMCs obtained from two H. pylori infected subjects. We determined the restriction molecules by antibody blocking and used various Epstein-Barr virus-transformed B lymphocyte cell lines (BLCLs) with different HLA alleles as APCs to present peptides to CD4(+) T cells. These epitopes were DRB1*1404-restricted UreB(373-385) and DRB1*0803-restricted UreB(438-452). The T cells specific to these epitopes not only recognized autologous DCs loaded with recombinant UreB but also those pulsed with H. pylori whole cell lysates, suggesting that these epitope peptides are naturally processed. These epitopes have important value for designing an effective H. pylori vaccine.

The Helicobacter pylori virulence effector CagA abrogates human β-defensin 3 expression via inactivation of EGFR signaling

Antimicrobial peptides are constituents of the first-line innate mucosal defense system that acts as a barrier to establishment of infection. The highly successful human gastric pathogen, Helicobacter pylori, is able to persistently colonize its host despite inducing expression of several antimicrobial peptides, including human β-defensin 3 (hBD3). We find that hBD3 is highly active against H. pylori in vitro and is rapidly induced during early infection via EGFR-dependent activation of MAP kinase and JAK/STAT signaling. However, during prolonged infection, hBD3 was subsequently downregulated by the H. pylori virulence determinant CagA. Upon translocation into host cells, CagA activated the cellular tyrosine phosphatase, SHP-2, terminating EGFR activation and downstream signaling and increasing bacterial viability. Chemical inhibition and knockdown of SHP-2 expression rescued hBD3 synthesis and bactericidal activity. Thus, we reveal how cagPAI-positive H. pylori strains use CagA to evade a key innate mucosal defense pathway to support the establishment of persistent infection.

Salvage Options for Eradication of Helicobacter pylori During Tetracycline Backorder

Objective:

To review salvage options for Helicobacter pylori eradication regimens during a tetracycline backorder for patients with triple-therapy failure.

Data Sources:

A search of PubMed (1980-June 2012) was conducted using a combination of the terms H. pylori or Helicobacter pylori, salvage therapy, and eradication or treatment as text word searches.

Study Selection and Data Extraction:

Clinical trials and meta-analyses published in English were included. A manual review of the bibliographies of available literature was conducted and relevant articles were reviewed for inclusion.

Data Synthesis:

Treatment of H. pylori consists of a triple-drug regimen that includes a proton pump inhibitor (PPI), amoxicillin or metronidazole, and clarithromycin. Failure with this therapy is becoming increasingly common due to macrolide resistance. Upon failure with this regimen, it is recommended that a quadruple regimen with bismuth subsalicylate, metronidazole, tetracycline, and a histamine2 receptor antagonist or a PPI be used. Recent backorders by the 2 manufacturers for tetracycline restrict the use of this regimen. Options that can be considered include minocycline or doxycycline in place of tetracycline, levofloxacin- or moxifloxacin-based regimens, a tinidazole-based regimen, or a rifabutin-based regimen. This article includes a review of 1 study each of minocycline and doxycycline, 5 levofloxacin studies (including meta-analyses), 2 moxifloxacin studies, 1 rifabutin study, and 1 tinidazole study. There are limited data with other tetracyclines; however, given the resistance to quinolones in some areas and possible drug interactions and adverse effects from rifabutin, minocycline or doxycycline regimens may be a better second-line regimen option.

Conclusions:

Given the current tetracycline shortage, minocycline and doxycycline are options to be considered in patients with a macrolide-based treatment failure. Fluoroquinolones may be an option for patients who have not received these drugs for other indications in the recent past or in areas where resistance is low.

Significance of Helicobacter pylori vacA intermediate region genotyping-a Bulgarian study

The significance of the intermediate (i) region of the Helicobacter pylori vacA gene as a virulence factor associated with the severity of gastric disease is still disputable. The aim of the present study was to evaluate the prevalence and significance of vacA i alleles alone or in combination with other vacA alleles in symptomatic Bulgarian patients and to find out possible associations between vacA i genotype and patients' disease, age, sex, and other H. pylori virulence factors. Unlike vacA s1 and m1, vacA i1 prevalence was significantly higher (75.0%) in strains from peptic ulcer patients than in strains from nonulcer patients with gastric diseases (58.6%) (P = 0.022). Less virulent vacA s1 i2 m2 strains were more prevalent in females (P = 0.03), and cagA(+) was associated with vacA i1, s1, m1, and their combinations. In conclusion, vacA i status is a better predictor for the strain virulence than other vacA alleles.

Association between cagA and vacA genotypes and pathogenesis in a Helicobacter pylori infected population from South-eastern Sweden

Background

Chronic gastritis, peptic ulcer disease, and gastric cancer have been shown to be related to infection with Helicobacter pylori (H. pylori). Two major virulence factors of H. pylori, CagA and VacA, have been associated with these sequelae of the infection. In this study, total DNA was isolated from gastric biopsy specimens to assess the cagA and vacA genotypes.

Results

Variations in H. pylori cagA EPIYA motifs and the mosaic structure of vacA s/m/i/d regions were analysed in 155 H. pylori-positive gastric biopsies from 71 individuals using PCR and sequencing. Analysis of a possible association between cagA and vacA genotypes and gastroduodenal pathogenesis was made by logistic regression analysis. We found that H. pylori strains with variation in the number of cagA EPIYA motif variants present in the same biopsy correlated with peptic ulcer, while occurrence of two or more EPIYA-C motifs was associated with atrophy in the gastric mucosa. No statistically significant relation between vacA genotypes and gastroduodenal pathogenesis was observed.

Conclusions

The results of this study indicate that cagA genotypes may be important determinants in the development of gastroduodenal sequelae of H. pylori infection. In contrast to other studies, vacA genotypes were not related to disease progression or outcome. In order to fully understand the relations between cagA, vacA and gastroduodenal pathogenesis, the mechanisms by which CagA and VacA act and interact need to be further investigated.

Iron trafficking system in Helicobacter pylori

Helicobacter pylori infections are closely associated with peptic ulcers, gastric malignancy and iron deficiency anemia. Iron is essential for almost all living organisms and the investigation of iron uptake and trafficking system is thus important to understand the pathological roles of H. pylori. Up to now, the iron trafficking system of H. pylori is not yet fully clear and merits further efforts in this regards. The available information about iron uptake and regulation has been discussed in this concise review, such as FeoB in ferrous transportation, FrpB2 in hemoglobin uptake, HugZ in heme processing, virulence factors (VacA and CagA) in transferrin utilization, Pfr and NapA in iron storage and Fur in iron regulation. The identified iron trafficking system will help us to understand the pathological roles of H. pylori in the various gastric diseases and iron deficiency anemia and stimulates further development of effective anti-bacterial drugs.

Multifaceted interactions of bacterial toxins with the gastrointestinal mucosa

The digestive tract is one of the ecosystems that harbors the largest number and greatest variety of bacteria. Among them, certain bacteria have developed various strategies, including the synthesis of virulence factors such as toxins, to interact with the intestinal mucosa, and are responsible for various pathologies. A large variety of bacterial toxins of different sizes, structures and modes of action are able to interact with the gastrointestinal mucosa. Some toxins, termed enterotoxins, directly stimulate fluid secretion in enterocytes or cause their death, whereas other toxins pass through the intestinal barrier and disseminate by the general circulation to remote organs or tissues, where they are active. After recognition of a membrane receptor on target cells, toxins can act at the cell membrane by transducing a signal across the membrane in a hormone-like manner, by pore formation or by damaging membrane compounds. Other toxins can enter the cells and modify an intracellular target leading to a disregulation of certain physiological processes or disorganization of some structural architectures and cell death. Toxins are fascinating molecules, which mimic or interfere with eukaryotic physiological processes. Thereby, they have permitted the identification and characterization of new natural hormones or regulatory pathways. Besides use as protective antigens in vaccines, toxins offer multiple possibilities in pharmacology, such as immune modulation or specific delivery of a protein of interest into target cells.

Variation in number of cagA EPIYA-C phosphorylation motifs between cultured Helicobacter pylori and biopsy strain DNA

The Helicobacter pylori cagA gene encodes a cytotoxin which is activated by phosphorylation after entering the host epithelial cell. Phosphorylation occurs on specific tyrosine residues within EPIYA motifs in the variable 3'-region. Four different cagA EPIYA motifs have been defined according to the surrounding amino acid sequence; EPIYA-A, -B, -C and -D. Commonly, EPIYA-A and -B are followed by one or more EPIYA-C or -D motif. Due to observed discrepancies in cagA genotypes in cultured H. pylori and the corresponding DNA extracts it has been suggested that genotyping assays preferentially should be performed directly on DNA isolated from biopsy specimens. Gastric biopsies randomly selected from a Swedish cohort were homogenised and used for both direct DNA isolation and for H. pylori specific culturing and subsequent DNA isolation. In 123 of 153 biopsy specimens, the cagA EPIYA genotypes were in agreement with the corresponding cultured H. pylori strains. A higher proportion of mixed cagA EPIYA genotypes were found in the remaining 30 biopsy specimens. Cloning and sequencing of selected cagA EPIYA amplicons revealed variations in number of cagA EPIYA-C motifs in the mixed amplicons. The study demonstrates that culturing of H. pylori introduces a bias in the number of EPIYA-C motif. Consistent with other H. pylori virulence genotyping studies, we suggest that cagA EPIYA analysis should be performed using total DNA isolated from biopsy specimens.

Regulation of the actin cytoskeleton in Helicobacter pylori-induced migration and invasive growth of gastric epithelial cells

Dynamic rearrangement of the actin cytoskeleton is a significant hallmark of Helicobacter pylori (H. pylori) infected gastric epithelial cells leading to cell migration and invasive growth. Considering the cellular mechanisms, the type IV secretion system (T4SS) and the effector protein cytotoxin-associated gene A (CagA) of H. pylori are well-studied initiators of distinct signal transduction pathways in host cells targeting kinases, adaptor proteins, GTPases, actin binding and other proteins involved in the regulation of the actin lattice. In this review, we summarize recent findings of how H. pylori functionally interacts with the complex signaling network that controls the actin cytoskeleton of motile and invasive gastric epithelial cells.

Comparative genomics of Helicobacter pylori and the human-derived Helicobacter bizzozeronii CIII-1 strain reveal the molecular basis of the zoonotic nature of non-pylori gastric Helicobacter infections in humans

BACKGROUND

The canine Gram-negative Helicobacter bizzozeronii is one of seven species in Helicobacter heilmannii sensu lato that are detected in 0.17-2.3% of the gastric biopsies of human patients with gastric symptoms. At the present, H. bizzozeronii is the only non-pylori gastric Helicobacter sp. cultivated from human patients and is therefore a good alternative model of human gastric Helicobacter disease. We recently sequenced the genome of the H. bizzozeronii human strain CIII-1, isolated in 2008 from a 47-year old Finnish woman suffering from severe dyspeptic symptoms. In this study, we performed a detailed comparative genome analysis with H. pylori, providing new insights into non-pylori Helicobacter infections and the mechanisms of transmission between the primary animal host and humans.

RESULTS

H. bizzozeronii possesses all the genes necessary for its specialised life in the stomach. However, H. bizzozeronii differs from H. pylori by having a wider metabolic flexibility in terms of its energy sources and electron transport chain. Moreover, H. bizzozeronii harbours a higher number of methyl-accepting chemotaxis proteins, allowing it to respond to a wider spectrum of environmental signals. In this study, H. bizzozeronii has been shown to have high level of genome plasticity. We were able to identify a total of 43 contingency genes, 5 insertion sequences (ISs), 22 mini-IS elements, 1 genomic island and a putative prophage. Although H. bizzozeronii lacks homologues of some of the major H. pylori virulence genes, other candidate virulence factors are present. In particular, we identified a polysaccharide lyase (HBZC1_15820) as a potential new virulence factor of H. bizzozeronii.

CONCLUSIONS

The comparative genome analysis performed in this study increased the knowledge of the biology of gastric Helicobacter species. In particular, we propose the hypothesis that the high metabolic versatility and the ability to react to a range of environmental signals, factors which differentiate H. bizzozeronii as well as H. felis and H. suis from H. pylori, are the molecular basis of the of the zoonotic nature of H. heilmannii sensu lato infection in humans.

DNA repair gene polymorphisms and risk of chronic atrophic gastritis: a case-control study

Background

Recent studies have reported associations of DNA repair pathway gene variants and risk of various cancers and precancerous lesions, such as chronic atrophic gastritis (CAG).

Methods

A nested case-control study within the German population-based ESTHER cohort was conducted, including 533 CAG cases and 1054 controls. Polymorphisms in eleven DNA repair genes (APEX1, ERCC1, ERCC2/XPD, PARP1 and XRCC1), in CD3EAP/ASE-1 and PPP1R13L were analysed.

Results

No association was disclosed for any of the analysed polymorphisms. Nor did stratified analyses according to ages < 65 and ≥ 65 years show any significant association with CAG risk.

Conclusions

The results of this large German case-control study do not reveal associations of DNA repair pathway polymorphisms and risk of CAG. On the basis of a large number of CAG cases, they do not support associations of DNA repair pathway SNPs with CAG risk, but suggest the need of larger studies to disclose or exclude potential weak associations, or of studies with full coverage of candidate genes.

Circulating interleukin-27 levels in Helicobacter pylori-infected patients with gastric or duodenal ulcers, independent of the bacterial cytotoxin-associated gene A virulence factor

OBJECTIVE

The aim was to evaluate the interleukin (IL)-27 levels in Helicobacter pylori (H. pylori)-infected patients with gastric ulcer (GU) or duodenal ulcer (DU) and to determine its association with H. pylori virulence factor cytotoxin-associated gene A (CagA).

METHODS

In all, 127 H. pylori infected patients (including 96 DU patients, of whom 61 were anti-CagA(+) and 35 were anti-CagA(-)) and 31 GU patients (of whom 15 were anti-CagA(+) and 16 were anti-CagA(-)), 60 asymptomatic (AS) carriers (of whom 30 were anti-CagA(+) and 30 were anti-CagA(-)) and 30 healthy H. pylori-negative participants (as a control) were enrolled in the study. Serum concentrations of IL-27 were measured by the enzyme-linked immunosorbent assay method.

RESULTS

The mean levels of IL-27 in the GU (44.26 ± 7.12 pg/mL) and DU patients (40.84 ± 3.90 pg/mL) was significantly higher than those observed in the AS carriers (22.06 ± 1.90 pg/mL, P < 0.001) and the control group (18.12 ± 1.68 pg/mL, P < 0.001 and P < 0.002, respectively). In the GU, DU and AS groups the levels of IL-27 in anti-CagA(+) participants were not significantly differ from that in the anti-CagA(-) participants.

CONCLUSIONS

These results showed that the mean concentration of IL-27 in H. pylori-infected peptic ulcer (PU) patients was higher than in AS carriers and the healthy control group. The serum concentrations of IL-27 were not affected by the CagA factor.

Review of proton pump inhibitors for the initial treatment of heartburn: is there a dose ceiling effect?

Proton pump inhibitors (PPIs) are widely used in clinical practice. However, concerns have been expressed about their long-term use, particularly with regard to bone health, Clostridium difficile infections, and drug interactions with platelet aggregation inhibitors. There has been limited guidance for clinicians concerning appropriate dose selection of PPIs for the initial treatment of heartburn. This review explored whether published clinical trials provide evidence of a ceiling above which higher PPI doses do not provide additional clinical benefit over the lowest approved dose. All articles of randomized, controlled clinical trials in nonerosive gastroesophageal reflux disease (GERD) in which the effects of two or more doses of the same PPI on symptomatic relief of heartburn were quantified as a study endpoint were identified and analyzed through PubMed searches up to the end of September 2010. The majority of trials evaluated provided no evidence that higher PPI doses were superior to the lowest approved dose for the initial treatment of heartburn. There were no clinically relevant findings with respect to dose dependence and safety outcomes in these studies. Efficacy outcomes from the trials suggest there may be a dose ceiling effect and highlight the need for further research on the use of the lowest effective PPI doses as an appropriate strategy in the initial treatment of uncomplicated heartburn. Observational studies and some meta-analyses have suggested that long-term PPI pharmacotherapy might be associated with safety concerns, which necessitate the periodic evaluation of therapeutic benefit in terms of symptom resolution and regimen tolerability. However, evidence to date suggests that use of the lowest effective dose for the indication is not associated with significant adverse events, particularly in the short term. Clinical practice suggests that patients requiring long-term treatment should be maintained on the lowest dose necessary to control symptoms, and monitored for potentially confounding factors that may lead to safety concerns.