Helicobacter pylori genotyping and sequencing using paraffin-embedded biopsies from residents of colombian areas with contrasting gastric cancer risks

Helicobacter pylori Infection Elicits Type I Interferon Response in Human Monocytes via Toll-Like Receptor 8 Signaling

Helicobacter pylori colonization and persistence could precede gastric adenocarcinoma. Elucidating immune recognition strategies of H. pylori is therefore imperative to curb chronic persistence in the human host. Toll-like receptor 7 (TLR7) and TLR8 are widely known as viral single-stranded RNA (ssRNA) sensors yet less studied in the bacteria context. Here, we investigated the involvement of these receptors in the immunity to H. pylori. Human THP-1 monocytic cells were infected with H. pylori, and the expression levels of human Toll-like receptors (TLRs) were examined. The roles of TLR7 and TLR8 in response to H. pylori infection were further investigated using receptor antagonists. Among all TLR transcripts examined, TLR8 exhibited the most prominent upregulation, followed by TLR7 in the THP-1 cells infected with H. pylori J99 or SS1 strains. H. pylori infection-mediated IFN-α and IFN-β transactivation was significantly abrogated by the TLR7/8 (but not TLR7) antagonist. Additionally, TLR7/8 antagonist treatment reduced H. pylori infection-mediated phosphorylation of interferon regulatory factor 7 (IRF7). Our study suggests a novel role of TLR8 signaling in host immunity against H. pylori through sensing live bacteria to elicit the production of type I interferon.

Virulence Genes of Helicobacter pylori Increase the Risk of Premalignant Gastric Lesions in a Colombian Population

BACKGROUND

Genetic variability of Helicobacter pylori is associated with various gastrointestinal diseases; however, little is known about interaction with sociodemographic in the development of premalignant lesions in Colombian patients.

METHODS

An analytical study was conducted including cases (patients with gastric atrophy, intestinal metaplasia, and gastric dysplasia) and controls (patients with nonatrophic gastritis). Sociodemographic information was obtained using a questionnaire. Histopathological diagnosis was performed according to the Sydney System. The cagA and vacA genotypes were established using polymerase chain reaction in paraffin blocks. The effect of each variable on the study outcome (premalignant lesion) is presented as odds ratio (OR) and 95% CI. A p value of <0.05 was considered as statistically significant.

RESULTS

The vacA/s1m1 genotype increases the risk of developing premalignant lesions of the stomach (OR: 3.05, 95% IC: 1.57-5.91, p=0.001). Age and educational level showed a positive interaction with the s1m1 genotype (adjusted OR: 3.68, 95% CI: 1.73-7.82, p=0.001). The cagA genotype was not correlated to the development of premalignant lesions of the stomach (OR: 1.32, 95% CI: 0.90-1.94, p=0.151).

CONCLUSIONS

The vacA genotype, age, and educational level are indicators of the risk of developing premalignant lesions of the stomach in the study population. Significance Statement. Genetic variability of H. pylori and sociodemographic information could be used to predict the risk of premalignant lesions in stomach in Colombian population.

Helicobacter pylori genotypes associated with gastric cancer and dysplasia in Colombian patients

INTRODUCTION AND AIMS

Colombia has high incidence levels of gastric cancer that can be explained by the genetic variability of Helicobacter pylori (H. pylori). Our aim was to establish the relation of the H. pylori CagA and VacA genotypes to dysplasia and gastric cancer, in a high-risk population.

MATERIAL AND METHODS

A case-control study was conducted on 202 patients from a high-risk cancer zone. Patients with dysplasia and gastric cancer (cases) and patients with nonatrophic gastritis (controls) were included. Endoscopic sampling and histologic classification were carried out according to the Sydney system and the Lauren classification. Genetic information was obtained through polymerase chain reaction on paraffin blocks. The measures of association of the variables of interest were evaluated in bivariate and multivariate models. A P<0.05 was considered statistically significant and the SPSS version 25 program was employed.

RESULTS

Age above 50 years (OR: 23.76; CI: 8.40-67.17; P=0.000) and the VacA s1m1 genotype (OR: 6.18; CI: 1.25-30.51; P=0.025) were associated with higher risk for developing dysplasia and gastric cancer. The CagA+ genotype was not found to be a risk factor for developing those pathologies (OR: 1.02; CI: 0.39-2.62; P=0.965).

CONCLUSIONS

The H. pylori VacA genotypes are markers for the development of gastric cancer. That information could be used to create a risk index in a predictive model to optimize the healthcare of higher-risk patients.

Circulating methylated THBS1 DNAs as a novel marker for predicting peritoneal dissemination in gastric cancer

Objectives

Thrombospondin 1 (THBS1) is known to play a key role in tumor metastasis, and aberrant DNA methylation is one of the mechanisms regulating THBS1. The present study investigated whether methylated THBS1 in circulating cell‐free DNA from preoperative peritoneal lavage fluid (PPLF) and peripheral blood could be used as a potential biomarker for predicting peritoneal dissemination in gastric cancer (GC) patients.

Methods

The status of THBS1 methylation was detected by quantitative methylation‐specific PCR (MSP) in tumor tissues, paired PPLF, and serum from 92 GC patients. The correlation between methylated THBS1 levels and peritoneal dissemination of GC was studied, and its diagnostic value for predicting peritoneal dissemination was clarified by the receiver operating characteristic (ROC) curve.

Results

Aberrant THBS1 methylation in tumor tissues was significantly higher than that in paracancerous normal tissues (p < 0.0001). No THBS1 methylation was found in 40 healthy controls, and partial methylation was detected in 3 of 48 patients with chronic non‐atrophic gastritis. The frequency of THBS1 methylation in pairing PPLF and serum from 92 GC patients was 52.2% (48/92) and 58.7% (54/92), respectively. The results of methylated THBS1 in pairing PPLF and serum were similar to those of tumor tissues. Aberrant THBS1 methylation in tumor tissues and pairing PPLF or serum was closely related to peritoneal dissemination, tumor progression, and poor prognosis (all p < 0.0001).

Conclusion

Circulating methylated THBS1 DNAs in PPLF/serum may predict peritoneal dissemination, a potential poor prognostic factor for GC patients.

Helicobacter pylori genotypes associated with gastric cancer and dysplasia in Colombian patients

INTRODUCTION AND AIMS

Colombia has high incidence levels of gastric cancer that can be explained by the genetic variability of Helicobacter pylori (H. pylori). Our aim was to establish the relation of the H. pylori CagA and VacA genotypes to dysplasia and gastric cancer, in a high-risk population.

MATERIAL AND METHODS

A case-control study was conducted on 202 patients from a high-risk cancer zone. Patients with dysplasia and gastric cancer (cases) and patients with nonatrophic gastritis (controls) were included. Endoscopic sampling and histologic classification were carried out according to the Sydney system and the Lauren classification. Genetic information was obtained through polymerase chain reaction on paraffin blocks. The measures of association of the variables of interest were evaluated in bivariate and multivariate models. A P<0.05 was considered statistically significant and the SPSS version 25 program was employed.

RESULTS

Age above 50 years (OR: 23.76; CI: 8.40-67.17; P=0.000) and the VacA s1m1 genotype (OR: 6.18; CI: 1.25-30.51; P=0.025) were associated with higher risk for developing dysplasia and gastric cancer. The CagA+ genotype was not found to be a risk factor for developing those pathologies (OR: 1.02; CI: 0.39-2.62; P=0.965).

CONCLUSIONS

The H. pylori VacA genotypes are markers for the development of gastric cancer. That information could be used to create a risk index in a predictive model to optimize the healthcare of higher-risk patients.

Helicobacter pylori in a poultry slaughterhouse: Prevalence, genotyping and antibiotic resistance pattern

Although Helicobacter pylori (H. pylori) is a highly significant pathogen, its source remains unclear. Many people consume chicken daily as a source of animal protein worldwide; thus, hygienic methods of supplying chickens for consumption are critical for public health. Therefore, our study examined the distribution of the glmM (ureC), babA2, vacA and cagA virulence genes in H. pylori strains in chicken meat and giblets (gizzards and livers) and the resistance of the strains to various antibiotics. Ninety chicken meat, gizzard and liver samples were obtained from a semi-automatic abattoir in Sadat City, Egypt, and were cultured and preliminarily analyzed using biochemical tests. The presence of the ureC, babA2, vacA and cagA genotypes was tested for in samples positive for H. pylori by multiplex polymerase chain reaction (Multiplex-PCR). The resistance of H. pylori to various antimicrobial drugs was tested using the disc diffusion method. In total, 7 of the 90 chicken samples were positive for H. pylori (7.78%); in 3/7 (42.85%) samples, the bacteria were found in the chicken liver, while the bacteria were found in the meat in 2/7 (28.57%) and in the gizzard in 2/7 (28.57%) samples. The total prevalence of both the ureC and babA2 genes in the isolated H. pylori strains was 100%, while the prevalence of the vacA and cagA genes was 57.1% and 42.9%, respectively. The resistance of H. pylori to the antibiotics utilized in our study was 100% for streptomycin; 85.7% for amoxicillin and penicillin; 71.4% for oxytetracycline, nalidixic acid and ampicillin; 57.1% for sulfamethoxazole and erythromycin; and 42.9% for neomycin, chloramphenicol and norfloxacin. In conclusion, the chicken meat and giblets were tainted by H. pylori, with a higher occurrence of the ureC, babA2, vacA and cagA genotypes. Future investigations should investigate the resistance of H. pylori to various antimicrobial agents in Egypt.

The Prevalence of Helicobacter pylori in Estonian Bariatric Surgery Patients

Helicobacter pylori (Hp) is one of the most important human pathogens that can cause duodenal and gastric ulcers, gastritis and stomach cancer. Hp infection is considered to be a cause of limiting access to bariatric surgery. The aim of this study was to determine the prevalence of Hp in patients with obesity going into bariatric surgery and to reveal the relationship between Hp and clinical data. The study group was formed of 68 preoperative bariatric surgery patients (body mass index (BMI) 44.7 ± 4.8). Gastric biopsies (antrum and corpus) were used for histological and molecular (caqA and glmM genes) examinations. The PCR method revealed Hp infection in 64.7% of obese patients that is higher in comparison with histological analysis (55.9%). The prevalence of cagA and glmM genes in antrum mucosa was 45.6% and 47.0% while in the corpus it was 41.2% and 38.3%, respectively. The coincidence of both cagA and glmM virulence genes in the antrum and corpus mucosa was 33.8% and 22.1%, respectively. Either of the genes was found in 58.8% of antrum and 57.3% of corpus mucosa. Presence of caqA and glmM genes was in association with active and atrophic chronic gastritis. In conclusion, our study demonstrated that two thirds of morbidly obese patients undergoing bariatric surgery are infected with Hp and have a high prevalence of cagA and glmM virulence genes that points out the necessity for diagnostics and treatment of this infection before surgery.

Detection and Genotyping of Helicobacter pylori among Gastric ulcer and Cancer Patients from Saudi Arabia

BACKGROUND AND OBJECTIVES

Helicobacter pylori (H. pylori) infection is cause of several gastrointestinal diseases in humans. Virulence genes of H. pylori are associated with severity of disease and vary geographically. The aim of present study was to detect H. pylori in formalin-fixed paraffin-embedded (FFPE) tissues and further investigate prevalence of babA_2, cagA, iceA1_, iceA2, vacA s1/s2 and vacA m1/m2 genotypes in H. pylori from gastric cancer (GC) and gastric ulcer (GU) patients' biopsy samples.

METHODS

We used FFPE tissues of 35 GC and 10 GU patients' biopsy samples. Using Polymerase Chain Reaction (PCR), detection of H. pylori strain was performed by using specific primers targeting 16S rRNA and ureC encodes for phosphoglucosamine mutase genes. We have identified different virulence genes of H. pylori by PCR.

RESULTS

Of all the 45 samples tested, 20 GC and all 10 GU samples were positive for identification of H. pylori using specific genes (16S rRNA and ureC). The prevalence of babA₂ (100%) was significantly higher in GC as compared to GU (40%) samples. The rate of virulence genes vacAs1 was higher in both GU 8 (80%) and GC (100%).

CONCLUSIONS

Our study finds that vacAs1am1 and babA₂ are most prominent genotypes and may play role in development of Gastric cancer.

Effect of treatment failure on the CagA EPIYA motif in Helicobacter pylori strains from Colombian subjects

AIM

To evaluate effect of treatment failure on cagA and vacA genotypes in Helicobacter pylori (H. pylori) isolates from Colombia.

METHODS

One hundred and seventy-six participants infected with H. pylori from Colombia were treated during 14 d with the triple-standard therapy. Six weeks later, eradication was evaluated by ¹³C-Urea breath test. Patients with treatment failure were subjected to endoscopy control; biopsies obtained were used for histopathology and culture. DNA from H. pylori isolates was amplified using primers specific for cagA and vacA genes. The phylogenetic relationships among isolates obtained before and after treatment were established by conglomerate analysis based on random amplified polymorphic DNA (RAPD) fingerprinting.

RESULTS

Treatment effectiveness was at 74.6%. Of the participants with treatment failure, 25 accepted subjected to a second endoscopy. Prevalence of post-treatment infection was 64% (16/25) and 40% (10/25) by histology and culture, respectively. Upon comparing the cagA and vacA genotypes found before and after therapy, multiple cagA genotypes (cagA-positive and cagA-negative) were found before treatment; in contrast, cagA-negative genotypes decreased after treatment. vacA s1m1 genotype was highly prevalent in patients before and after therapy. The 3’cagA region was successfully amplified in 95.5% (21/22) of the isolates obtained before and in 81.8% (18/22) of the isolates obtained after treatment. In the isolates obtained from patients with treatment failure, it was found that 72.7% (16/22) presented alterations in the number of EPIYA motifs, compared to isolates found before treatment.

CONCLUSION

Unsuccessful treatment limits colonization by low-virulence strains resulting in partial and selective eradication in mixed infections, and acts on the cagA-positive strains inducing genetic rearrangements in cagA variable region that produces a loss or gain of EPIYA repetitions.

DNA Methylation Predicts Progression of Human Gastric Lesions

BACKGROUND

Development of the intestinal subtype of gastric adenocarcinoma is marked by a progression of histopathologic lesions. Residents of the Andean regions of Colombia are at high risk for gastric cancer.

METHODS

A cohort of 976 Colombian subjects was followed over 16 years examining effects of Helicobacter pylori eradication and treatment with antioxidants on progression of lesions. We performed methylation analysis of DNA from baseline antral biopsies from 104 subjects for whom follow-up data were available for at least 12 years. Methylation was quantitated for AMPH, CDKN2A, CDH1, EN1, EMX1, NKX6-1, PCDH10, RPRM, RSPO2, SORCS3, ZIC1, and ZNF610 genes, using Pyrosequencing.

RESULTS

Levels of DNA methylation were associated with baseline diagnosis for AMPH, EMX1, RPRM, RSPO2, SORCS3, and ZNF610. After adjusting for baseline diagnosis and H. pylori infection, methylation levels of AMPH, PCDH10, RSPO2, and ZNF610 had progression coefficients that increased and P values that decreased over 6, 12, and 16 years. Methylation for SORCS3 was associated with progression at all 3 time points but without the continual strengthening of the effect. Scores for mononuclear leukocytes, polymorphonuclear leukocytes, or intraepithelial lymphocytes were unrelated to progression.

CONCLUSIONS

Methylation levels of AMPH, PCDH10, RSPO2, SORCS3, and ZNF610 predict progression of gastric lesions independent of the effect of duration of H. pylori infection, baseline diagnosis, gender of the patient, or scores for mononuclear leukocytes, polymorphonuclear leukocytes, or intraepithelial lymphocytes.

IMPACT

DNA methylation levels in AMPH, PCDH10, RSPO2, SORCS3, and ZNF610 may contribute to identification of persons with gastric lesions likely to progress.

Prevalence and correlation with clinical diseases of Helicobacter pylori cagA and vacA genotype among gastric patients from Northeast China

Helicobacter pylori vacA and cagA genes have significant genetic heterogenicity, resulting in different clinical outcomes. Northeast part of China has reported high prevalence of H. pylori infections and gastric cancer. Hence, we investigated the H. pylori cagA and vacA genotypes with clinical outcomes in Northeast China. Gastric tissue samples (n = 169), chronic gastritis (GIs), gastric ulcer (GU), and gastric cancer (GC) were analysed for 16S rRNA ureA, cagA, and cagA genotypes by PCR. A total of 141 (84%) cases were found positive for H. pylori by 16S rRNA and ureA. GC showed high H. pylori infection (93%) compared with GIs (72%) and GU (84%). The vacAs1am1 was highly found in GC (40%) and GU (36%), vacAs1am2 in GIs (33%), vacAs1bm1 (14%) and vacAs1bm2 (8%) in GU cases, and s2m1 in normal cases (33%), while vacAs1cm1 showed low frequency in GIs (2%) and GU (3%) and GC showed negative result. The East-Asian cagA strain was highly observed in GC (43%), as compared to GIs (41%) and GU (20%). The East-Asian cagA/vacAs1am1 was significantly higher in GC (23%) than in GU (22%) and GIs (145) patients. The East-Asian type cagA with vacAs1a and vacAm1 is the most predominant genotype in H. pylori strains of Northeast China.

Prevalence of Helicobacter pylori vacA different genotypes in Isfahan, Iran

Background:

It is believed that the Helicobacter pylori (H. pylori) vacA gene, as a major virulence determinant (One of the major virulence determinant, not major), may be a risk factor for the development of gastroduodenal diseases. The frequency of vacA genotypes varies in different human populations. This study evaluated the prevalence of vacA alleles/genotypes among dyspeptic patients in Isfahan.

Materials and Methods:

One-hundred H. pylori-positive adult patients were examined in this study. After culture of gastric biopsies and DNA extraction from individual H. pylori isolates, the (all H. pylori strains harbor vacA alleles, please replace “presence” with “genotypes”) of the vacA s and m alleles were determined using polymerase chain reaction (PCR).

Results:

There were four vacA mosaicisms, including 28 for s1a/m1 (28%), 23 for s1b/m1 (23%), 26 for s1a/m2 (26%) and 23 for s1b/m2 (23%). The s2 allele was not found. The predominant vacA genotype in patients with non-ulcer dyspepsia and duodenal ulcer was s1a/m2, whereas in patients with adenocarcinoma was s1a/m1.

Conclusion:

The results showed there was no significant correlation between different genotypes of the vacA and the clinical outcomes and appears to vacA genotypes were not useful determinants for gastrointestinal diseases in our area.

In vitro effect of amoxicillin and clarithromycin on the 3’ region of cagA gene in Helicobacter pylori isolates

AIM: To evaluate the in vitro effect of amoxicillin and clarithromycin on the cag pathogenicity island (cag PAI).

METHODS: One hundred and forty-nine clinical isolates of Helicobacter pylori (H. pylori) cultured from gastric biopsies from 206 Colombian patients with dyspeptic symptoms from a high-risk area for gastric cancer were included as study material. Antimicrobial susceptibility was determined by the agar dilution method. Resistant isolates at baseline and in amoxicillin and clarithromycin serial dilutions were subjected to genotyping (cagA, vacA alleles s and m), Glu-Pro-Ile-Tyr-Ala (EPIYA) polymerase chain reaction and random amplified polymorphic DNA (RAPD). Images of the RAPD amplicons were analyzed by Gel-Pro Analyzer 4.5 program. Cluster analyses was done using SPSS 15.0 statistical package, where each of the fingerprint bands were denoted as variables. Dendrograms were designed by following Ward’s clustering method and the estimation of distances between each pair of H. pylori isolates was calculated with the squared Euclidean distance.

RESULTS: Resistance rates were 4% for amoxicillin and 2.7% for clarithromycin with 2% double resistances. Genotyping evidenced a high prevalence of the genotype cagA-positive/vacA s1m1. The 3’ region of cagA gene was successfully amplified in 92.3% (12/13) of the baseline resistant isolates and in 60% (36/60) of the resistant isolates growing in antibiotic dilutions. Upon observing the distribution of the number of EPIYA repetitions in each dilution with respect to baseline isolates, it was found that in 61.5% (8/13) of the baseline isolates, a change in the number of EPIYA repetitions lowered antibiotic pressure. The gain and loss of EPIYA motifs resulted in a diversity of H. pylori subclones after bacterial adjustment to changing conditions product of antibiotic pressure. RAPD PCR evidenced the close clonal relationship between baseline isolates and isolates growing in antibiotic dilutions.

CONCLUSION: Antibiotic pressure does not induce loss of the cag pathogenicity island, but it can lead - in most cases - to genetic rearrangements within the 3’ region cagA of the founding bacteria that can affect the level of tyrosine phosphorylation impacting on its cellular effects and lead to divergence of cagA-positive subclones.

Use of the noninvasive entero-test in the detection of Helicobacter pylori in children in an endemic area in Colombia

BACKGROUND AND OBJECTIVE

Gastric infection with Helicobacter pylori (H pylori), a strong risk factor for gastric cancer, is highly prevalent in children residing in the Colombian Andes. We aimed to validate the use of the Entero-test to culture and genotype H pylori strains from asymptomatic Colombian children.

METHODS

Children (ages 10-15 years, n = 110, 80 of which were H pylori positive by the urea breath test [UBT]) were subjected to the Entero-test, and strings were cultured and/or used for DNA extraction for polymerase chain reaction (PCR). These children had been treated for H pylori in 2007. A second population of children (ages 10-15 years, n = 95),which had not been previously treated, was also subjected to the Entero-test.

RESULTS

Of UBT-positive children in the treated group, 29 of 80 (36%) Entero-test samples were H pylori culture positive; 29 additional string extracts were tested by PCR for the H pylori virulence factors cagA and vacA. PCR from cultures and extracts yielded a sensitivity of 74% and specificity of 87%. In the untreated group, 16 of 94 UBT-positive children (17%) produced Entero-tests that were culture positive. Fifty-eight of 94 (62%) string extracts were PCR positive for cagA and/or vacA. In previously treated children, H pylori strains were more often the less virulent vacA s2 (P = 0.001), m2 (P = 0.006), and i2 genotypes (P = 0.039).

CONCLUSIONS

The Entero-test may be used as a noninvasive test to detect H pylori in asymptomatic children residing in high-risk areas for gastric cancer. Treatment of H pylori in children was associated with less virulent genotypes.

Non-invasive genotyping of Helicobacter pylori cagA, vacA, and hopQ from asymptomatic children

BACKGROUND

Helicobacter pylori infection is usually acquired in childhood, but little is known about its natural history in asymptomatic children, primarily due to the paucity of non-invasive diagnostic methods. H. pylori strains harboring cagA and specific alleles of hopQ and vacA are associated with increased risk for gastric cancer. Many studies of H. pylori virulence markers in children have the bias that symptomatic subjects are selected for endoscopy, and these children may harbor the most virulent strains. Our aim is to genotype cagA, hopQ, and vacA alleles in stool DNA samples of healthy Colombian children residing in an area with high incidence of gastric cancer, to avoid selection bias resulting from endoscopy.

METHODS

H. pylori status of 86 asymptomatic children was assessed by (13) C-urea breath test (UBT) and PCR. H. pylori 16S rRNA, cagA, hopQ, and vacA genes were amplified from stool DNA samples and sequenced.

RESULTS

UBT was positive in 69 (80.2%) of 86 children; in stool DNA analysis, 78.3% were positive by 16S rRNA PCR. cagA, vacA, and hopQ were detected in 66.1%, 84.6%, and 72.3% of stool DNA samples from 16S rRNA-positive children. Of the children's DNA samples, which revealed vacA and hopQ alleles, 91.7% showed vacA s1 and 73.7% showed type I hopQ. Type I hopQ alleles were associated with cagA positivity and vacA s1 genotypes (p < 0.0001).

CONCLUSIONS

Using stool DNA samples, virulence markers of H. pylori were successfully genotyped in a high percentage of the asymptomatic infected children, revealing a high prevalence of genotypes associated with virulence. Type I hopQ alleles were associated with the presence of cagA and the vacA s1 genotype.

Disruption of nitric oxide signaling by Helicobacter pylori results in enhanced inflammation by inhibition of heme oxygenase-1

A strong cellular cross-talk exists between the pathogen Helicobacter pylori and high-output NO production. However, how NO and H. pylori interact to signal in gastric epithelial cells and modulate the innate immune response is unknown. We show that chemical or cellular sources of NO induce the anti-inflammatory effector heme oxygenase-1 (HO-1) in gastric epithelial cells through a pathway that requires NF-κB. However, H. pylori decreases NO-induced NF-κB activation, thereby inhibiting HO-1 expression. This inhibitory effect of H. pylori results from activation of the transcription factor heat shock factor-1 by the H. pylori virulence factor CagA and by the host signaling molecules ERK1/2 and JNK. Consistent with these findings, HO-1 is downregulated in gastric epithelial cells of patients infected with cagA(+) H. pylori but not in gastric epithelial cells of patients infected with cagA(-) H. pylori. Enhancement of HO-1 activity in infected cells or in H. pylori-infected mice inhibits chemokine generation and reduces inflammation. These data define a mechanism by which H. pylori favors its own pathogenesis by inhibiting HO-1 induction through the action of CagA.

Helicobacter pylori and gastritis: Untangling a complex relationship 27 years on

Since its' introduction by Warren and Marshall 27 years ago, Helicobacter pylori (HP) has become the linchpin in our understanding of important gastric conditions including gastritis, intestinal metaplasia (IM), gastric/duodenal ulcers (GU/DU), Mucosal Associated Lymphoid Tumour (MALToma) and gastric cancer. Initially named Campylobacter pyloridis, it was re-named HP when biochemical and genetic characterization of the organism showed that it was not a member of the Campylobacter genus. The finding in 1983 was seminal. It is now recognized that HP is the most common chronic human bacterial infection and it is the most common cause of gastritis. It is strongly implicated in the development of peptic ulcer disease and gastric neoplasms. In the years since its' discovery, much headway has been made in the understanding of this ubiquitous organism that had remained elusive, with much work focused on eradication, in part driven by pharmaceutical research and development. Standard triple therapy emerged to eradicate HP. However, with the emergence of HP resistance, newer regimes have been put forth that include quadruple therapy, sequential therapy and a dizzying array of other combinations bent on eradicating HP. Much less is known about the natural history of HP, the different faces of HP internationally, HP eradication and its effect on gastritis, IM, GU/DU and gastric cancer. This review will address the changing face of HP in 2011.

Gastric cancer: an infectious disease

The role of infectious agents and chronic inflammation in carcinogenesis is being increasingly recognized. It has been estimated that about 18% of cancers are directly linked to infections, particularly gastric adenocarcinoma (Helicobacter pylori), cervical carcinoma (human papilloma viruses), and hepatocarcinoma (hepatitis B and C viruses). Multiple clinical trials of COX-2 inhibitors and other antiinflammatory agents have shown a beneficial effect on the development of diverse tumors, such as those of the colon, stomach, prostate, and breast. However, their mechanism of action is not completely understood and may differ among the infectious agents and tumor types. Because gastric adenocarcinomas account for more than 90% of all gastric malignancies, this review focuses on adenocarcinomas.

Promoter DNA hypermethylation in gastric biopsies from subjects at high and low risk for gastric cancer

Gene promoter CpG island hypermethylation is associated with Helicobacter pylori (H. pylori) infection and may be an important initiator of gastric carcinogenesis. To examine factors influencing methylation, we utilized bisulfite Pyrosequencing® technology for quantitative analysis of promoter DNA methylation in RPRM, APC, MGMT and TWIST1 genes using DNA from 86 gastric biopsies from Colombian residents of areas with high and low incidence of gastric cancer. H. pylori colonies were cultured from the same subjects, and gastric pathology was evaluated. Virulence factors cagA (including segments of the 3' end, encoding EPIYA polymorphisms) and vacA s and m regions were characterized in the H. pylori strains. Using univariate analysis, we found significantly elevated levels of RPRM and TWIST1 promoter DNA methylation in biopsies from residents of the high-risk region compared to those from residents of the low-risk region. The presence of cagA and vacA s1m1 alleles were independently associated with elevated levels of promoter DNA methylation of RPRM and MGMT. Using multivariate analysis, DNA methylation of RPRM was associated with location of residence, cagA and vacA s1m1 status and methylation of TWIST1. We conclude that cagA and vacA virulence determinants are significantly associated with quantitative differences in promoter DNA methylation in these populations, but that other as yet undefined factors that differ between the populations may also contribute to variation in methylation status.

Diagnosis of Helicobacter pylori infection

The articles published this last year in the field of Helicobacter pylori diagnosis reported the development of in vivo histology, small improvements in some invasive methods (urease test, culture, and histology) and new kits for the stool antigen tests. They also contributed to increasing our knowledge, by further exploration into specific conditions for the urea breath test and into the significance of cagA antibodies. The role of serum markers of atrophy was also confirmed. Molecular methods are still being developed for direct genotyping, detection of H. pylori and its clarithromycin resistance, either by polymerase chain reaction or fluorescent in-situ hybridization. For the first time, there was a report on a possible interest of magnetic resonance spectroscopy.

CagA C-terminal variations in Helicobacter pylori strains from Colombian patients with gastric precancerous lesions

The C-terminus of the Helicobacter pylori CagA protein is polymorphic, bearing different EPIYA sequences (EPIYA-A, B, C or D), and one or more CagA multimerization (CM) motifs. The number of EPIYA-C motifs is associated with precancerous lesions and gastric cancer (GC). The relationship between EPIYA, CM motifs and gastric lesions was examined in H. pylori-infected Colombian patients from areas of high and low risk for GC. Genomic DNA was extracted from H. pylori strains cultured from gastric biopsies from 80 adults with dyspeptic symptoms. Sixty-seven (83.8%) of 80 strains were cagA positive. The 3' region of cagA was sequenced, and EPIYA and CM motifs were identified. CagA proteins contained one (64.2%), two (34.3%) or three EPIYA-C motifs (1.5%), all with Western type CagA-specific sequences. Strains with one EPIYA-C motif were associated with less severe gastric lesions (non-atrophic and multifocal atrophic gastritis), whereas strains with multiple EPIYA-C motifs were associated with more severe lesions (intestinal metaplasia and dysplasia) (p <0.001). In 54 strains, the CM motifs were identical to those common in Western strains. Thirteen strains from the low-risk area contained two different CM motifs: one of Western type located within the EPIYA-C segment and another following the EPIYA-C segment and resembling the CM motif found in East Asian strains. These strains induced significantly shorter projections in AGS cells and an attenuated reduction in levels of CagA upon immunodepletion of SHP-2 than strains possessing Western/Western motifs. This novel finding may partially explain the difference in GC incidence in these populations.

Helicobacter pylori vacA arrangement and related diseases: a retrospective study over a period of 15 years

Peptic ulcer disease incidence is decreasing. Both s1m1 and s1m2 vacA gene combinations of Helicobacter pylori have been associated with the development of major gastroduodenal diseases. This study assessed whether H. pylori vacA gene arrangement changed over 15 years in a Southern Italy area. H. pylori-positive patients observed in January-June 1989 and January-June 2005 were selected. Histological specimens were retrieved to extract DNA for vacA arrangement characterization (mid-m and peptide signal-s regions) by using the polymerase chain reaction. Fifty-nine patients in the first period and 56 matched patients in the second period were evaluated. A correlation between s1 presence and intestinal metaplasia at histology was found. Overall, the s1m1 combination increased (P < 0.01) and s2m2 decreased (P < 0.001) during the study period. In detail, s1m1 (P < 0.05) and s1m2 (P < 0.01) increased, and s2m2 decreased (P < 0.001) in dyspeptic patients, while only s1m1 increased (P < 0.01) in peptic ulcer patients. Finally, few cases of s2m1 combination in both series were found. Our results show some unexpected aspects that require confirmation. In detail, the increased prevalence of potential more virulent H. pylori strains contrasts with peptic ulcer incidence reduction.

Eosinophils and mast cells in chronic gastritis: possible implications in carcinogenesis

Eosinophils and mast cells participate in the immune response against Helicobacter pylori, but their involvement in the gastric precancerous process is unclear. This study aimed to estimate eosinophil and mast cell density in antral mucosa in subjects from 2 Colombian populations with contrasting gastric cancer risks. Gastric mucosa biopsies were collected from 117 adult males (72 from a high-risk area and 45 from a low-risk area). A histopathology score was used to quantify severity of the lesions. Quantitation of eosinophils in hematoxylin-eosin-stained sections and mast cells in immunostained sections for CD117/c-Kit was performed. Helicobacter pylori infection and genotyping were assessed in Steiner stain and polymerase chain reaction, respectively. Logistic regression models and semiparametric cubic smoothing splines were used for analysis of the results. Eosinophil density was significantly higher in subjects from the low-risk area as compared with subjects from the high-risk area. In both populations, eosinophil density increased with the histopathology score in the progression of lesions from normal morphology to multifocal atrophic gastritis. Intestinal metaplasia and dysplasia specimens showed further increase in eosinophil density in the high-risk area but an abrupt decrease in the low-risk area. Mast cell density increased in parallel to the histopathology score in both populations. Our results suggest that eosinophils play a dual role in chronic gastritis. In the low-risk area, elevated eosinophil density represents a T helper 2-biased response that may down-regulate the effects of proinflammatory cytokines preventing cancer development. In contrast, in the high-risk area, eosinophils might promote a T helper 1-type response leading to progression of precancerous lesions.

Natural history of Helicobacter pylori infection

This report describes the modalities of chronic gastritis induced by Helicobacter pylori infection in different populations. The full gamut of lesions representing the precancerous cascade is very prevalent in populations of low socioeconomic background experiencing very high gastric cancer risk, as seen in the Latin American Andes Mountains. In populations of high socioeconomic standards and high cancer risk, such as Japan and Korea, the precancerous cascade predominates and "early" cancers are also diagnosed frequently. Some reports describe frequent corpus atrophy, not prominent in the former group. The so-called African enigma is seen in populations of low socioeconomic standards, usually living at low altitudes, with high prevalence of infection but low frequency of cancer and precancerous lesions. In populations in transition from high to low cancer risk, duodenal ulcer and antral non-atrophic gastritis are frequently seen. In affluent societies at low risk of cancer, such as Western Europe, Australia and North America, mild non-atrophic gastritis associated with low virulence Helicobacter pylori genotypes predominate. The varied phenotypes of gastritis may reflect secular changes in the ecology of our species.