Helicobacter pylori: consensus and controversy

Helicobacter pylori and Gastrointestinal Cancers: Recent Advances and Controversies

Helicobacter pylori (H pylori), a gastric bacterium, has been extensively studied for its association with gastritis, peptic ulcers, and gastric cancer. However, recent evidence suggests its potential implications beyond the stomach, linking it to other gastrointestinal malignancies, such as esophageal cancer, liver cancer, pancreatic cancer, gallbladder cancer, and colorectal cancer. In light of the expanding research landscape and the increasing interest in exploring H pylori broader role in gastrointestinal tumorigenesis, this comprehensive review aims to elucidate the relationship between H pylori and gastrointestinal tumors. This review encompasses recent epidemiological studies, research progress, and emerging perspectives, providing a comprehensive assessment of the relationship between H pylori and gastrointestinal tumors. The findings highlight the captivating world of H pylori and its intricate involvement in gastrointestinal malignancies.

Helicobacter pylori and gastric cardia cancer: What do we know about their relationship?

The incidence of gastric cardia cancer is increasing around the world. Since the discovery of Helicobacter pylori (H. pylori), numerous studies have proved that it is a causative factor for many kinds of digestive system tumors. Although the literature on gastric cardia cancer and H. pylori is not scarce, there are still many controversies on the relationship between gastric cardia cancer and H. pylori. Many Western research results showed that there was a negative or no correlation between H. pylori infection and gastric cardia cancer, but in several studies in Asian countries, such as China, H. pylori was demonstrated to be a risk factor for gastric cardia cancer. Therefore, we intended to analyze the related studies to find out the relationship between H. pylori and gastric cardia cancer and find out the causes of the above controversies. We also conducted a meta-analysis of the relationship between cagA positive expression of H. pylori and gastric cardia cancer, to find out whether there is an effect between those two. The primary purpose of this paper was to explore the relationship between gastric cardia cancer and H. pylori. Through analysis, the study showed the reasons for the controversies mentioned above: (1) Geographical factors could affect the relationship between H. pylori and gastric cardia cancer; (2) The definition of gastric cardia cancer in various studies is inconsistent. The result of a meta-analysis about the relationship between H. pylori virulence factor cagA and gastric cardia cancer showed that there was no relationship between these two.

An Additive Effect of Oral N-Acetyl Cysteine on Eradication of Helicobacter pylori

Background. Helicobacter pylori is highly adapted to the gastric environment where it lives within or beneath the gastric mucous layer. The aim of this study was to evaluate whether the addition of N-acetyl cysteine to the treatment regimen of H. pylori infection would affect eradication rates of the disease. Methods. A total of 79 H. pylori positive patients were randomized to two therapeutic groups. Both groups received a 14-day course of three-drug regimen including amoxicillin/clarithromycin/omeprazole. Experimental group (38 subjects) received NAC, and control group (41 subjects) received placebo, besides three-drug regimen. H. pylori eradication was evaluated by urea breath test at least 4 weeks after the cessation of therapy. Results. The rate of H. pylori eradication was 72.9% and 60.9% in experimental and control groups, respectively (P = 0.005). By logistic regression modeling, female gender (OR 3.68, 95% CI: 1.06–5.79; P = 0.040) and treatment including NAC (OR 1.88, 95% CI: 0.68–3.15; P = 0.021) were independent factors associated with H. pylori eradication. Conclusion. The results of the present study show that NAC has an additive effect on the eradication rates of H. pylori obtained with three-drug regimen and appears to be a promising means of eradicating H. pylori infection.

Preferences for the "screen and treat" strategy of Helicobacter pylori to prevent gastric cancer in healthy Korean populations

BACKGROUND

Helicobacter pylori (HP) eradication may reduce the risk of gastric cancer, and professional guidelines recommend eradication based on patients' preference. However, little data exist regarding individual's preference for HP eradication to prevent gastric cancer. We explored healthy Korean populations' preference for HP "screen and treat" strategy and its associated factors.

METHODS

We conducted a cross-sectional survey with 604 healthy adults expected to undergo screening esophagogastroduodenoscopy during routine health checkups. Survey packages-including a decision aid about "screen and treat" strategy for the HP eradication-were sent to the eligible people 1-3 weeks before the health checkup. Within the survey package, we first assessed people's knowledge and experience with HP test and treatment, provided the decision aid, and evaluated participants' preference for screening and treatment for HP to prevent gastric cancer.

RESULTS

With the provision of the decision aid, most participants (73.7%) opted for the "screen and treat" strategy. Having family member(s) with gastric cancer (adjusted odds ratio (aOR) = 2.28; 95% confidence interval (CI), 1.16-4.47), previous treatment history of HP (aOR = 2.70; 95% CI, 1.38-5.29), and higher baseline knowledge (aOR = 1.16; 95% CI, 1.07-1.26) were significantly associated with accepting the strategy. Most participants (71.4%)-and even individuals who did not choose "screen and treat" strategy-agreed with the provision with the decision aid.

CONCLUSIONS

Individuals preferred to take the "screen and treat" strategy for the prevention of gastric cancer. Further intervention study is warranted to see if implementation of decisional support would improve decision quality and patient outcomes.

Effects of alpha tocopherol and ascorbic acid on Helicobacter pylori colonization and the severity of gastric inflammation

BACKGROUND AND AIM

We aimed to evaluate the changes in histopathologic features, concentrations of vitamins C and E in gastric mucosa, and total antioxidant capacity of the body after ingestion of ascorbic acid and alpha tocopherol in patients with Helicobacter pylori.

MATERIAL AND METHOD

Patients with H. pylori-positive nonulcer dyspepsia were included in this study. Tissue samples were taken from the lesser and greater curvature in both prepyloric antrum and corpus for histopathologic examination and measurement of vitamins C and E concentrations. Blood samples were obtained for measurement of the total antioxidant capacity of the body. The patients were given vitamin C 500 mg BID and vitamin E 200 IU BID for 4 weeks orally. At the end of the 4th week, the initial procedures were repeated. Histopathologic examination of the tissue samples were carried out by two pathologists.

RESULTS

The mean vitamins C and E concentrations in gastric mucosa at the 4th week were higher than those at the beginning (p = .000 and p = .006, respectively). Mean total antioxidant capacity of the body at the beginning and that at the 4th week were similar (p = .689). H. pylori intensity in the antrum at the beginning was higher than that at the 4th week for both pathologists (p = .007 and p = .039). Neutrophilic activity in the antrum at the beginning was higher than that at the 4th week for both pathologists (p = .000 and p = .025). Neutrophilic activity in the corpus at the beginning was higher than that at the 4th week for pathologist 1 (p = .033), and they were similar for pathologist 2 (p = .763).

CONCLUSION

The findings that H. pylori intensity and neutrophilic activity decrease through increasing gastric ascorbic acid and alpha tocopherol concentrations suggest that supplementation with vitamins C and E increases the eradication rates via impairing the microenvironment created by the bacteria and facilitating the diffusion of antibiotics into gastric mucosa.

Association between herpes simplex virus type 1 and Helicobacter pylori in US adolescents

OBJECTIVE

To understand how Helicobacter pylori infection is acquired and the role that herpes simplex virus type 1 (HSV-1) may have, we determined whether an association between HSV and H pylori exists at the individual level and for what reason.

STUDY DESIGN

Data were collected from 1,090 participants aged 12-19 years during phase 1 (1988-1991) of the NHANES III. Generalized estimating equations were used to estimate prevalence ratios (PR).

RESULTS

The crude overall PR and 95% CI for H pylori seropositivity comparing HSV+ to HSV- individuals was 2.20 (1.69-2.85). In large urban households the PR adjusted for poverty level and race/ethnicity was twice that in small nonurban households (2.27 versus 1.15, respectively).

CONCLUSIONS

Overall, HSV-1 seropositivity is associated with a higher H pylori seroprevalence. The negligible association found in some strata suggests that shared environmental factors or routes of transmission rather than biologic reasons may be primarily responsible for this association.

Helicobacter pylori eradication in the management of patients with idiopathic thrombocytopenic purpura

PURPOSE

To investigate the relation between Helicobacter pylori infection and the clinical features of idiopathic thrombocytopenic purpura (ITP), and to examine the effects of H. pylori eradication on platelet counts.

METHODS

A(13)C urea breath test for H. pylori infection was performed in a cohort of 137 consecutive patients with ITP. Patients who tested positive received standard eradication therapy if their platelet count was <50 x 10(9)/L or if they had symptoms of dyspepsia.

RESULTS

H. pylori infection was detected in 64 patients (47%), and was not associated with dyspepsia or other clinical or laboratory features. Eradication therapy was successfully administered to 52 patients. Platelet responses were observed in 17 (33%) of these patients, which lasted for more than 1 year in 11 patients. Duration of ITP was shorter among responders than nonresponders. Only one response was observed among patients with severe thrombocytopenia (platelet count <30 x 10(9)/L).

CONCLUSION

The prevalence of H. pylori infection in patients with ITP is similar to that found in the general population. Infection is not associated with distinctive features of the disease. H. pylori eradication may improve the platelet counts in adults in whom the ITP is of recent onset and in those with less severe degrees of thrombocytopenia, but was not effective in patients with chronic severe ITP.

Comparison of Helicobacter pylori infection and gastric mucosal histological features of gastric ulcer patients with chronic gastritis patients

AIM: To compare Helicobacter pylori infection and gastric mucosal histological features of gastric ulcer patients with chronic gastritis patients in different age groups and from different biopsy sites.

METHODS: The biopsy specimens were taken from the antrum, corpus and upper angulus of gastric ulcer and chronic gastritis patients. Giemsa staining, improved Toluidine-blue staining and H pylori-specific antibody immune staining were performed as appropriate for the histological diagnosis of H pylori infection. Hematoxylin-eosin staining was used for the histological diagnosis of activity of H pylori infection, mucosal inflammation, glandular atrophy and intestinal metaplasia and scored into four grades according to the Updated Sydney System.

RESULTS: Total rate of H pylori infection, mucosal inflammation, activity of H pylori infection, glandular atrophy and intestinal metaplasia in 3839 gastric ulcer patients (78.5%, 97.4%, 82.1%, 61.1% and 64.2%, respectively) were significantly higher than those in 4102 chronic gastritis patients (55.0%, 90.3%, 56.2%, 36.8%, and 37.0%, respectively, P<0.05). The rate of H pylori colonization of chronic gastritis in <30 years, 31-40 years, 41-50 years, 51-60 years, 61-70 years and >70 years age groups in antrum was 33.3%, 41.7%, 53.6%, 57.3%, 50.7%, 43.5%, respectively; in corpus, it was 32.6%, 41.9%, 53.8%, 60.2%, 58.0%, 54.8%, respectively; in angulus, it was 32.4%, 42.1%, 51.6%, 54.5%, 49.7%, 43.5%, respectively. The rate of H pylori colonization of gastric ulcer in <30 years, 31-40 years, 41-50 years, 51-60 years, 61-70 years and >70 years age groups in antrum was 60.5%, 79.9%, 80.9%, 66.8%, 59.6%, 45.6%, respectively; in corpus, it was 59.7%, 79.6%, 83.6%, 80.1%, 70.6%, 59.1%, respectively; in angulus, it was 61.3%, 77.8%, 75.3%, 68.8%, 59.7%, 45.8%, respectively. The rate of H pylori colonization at antrum was similar to corpus and angulus in patients, below 50 years, with chronic gastritis and in patients, below 40 years, with gastric ulcer. In the other age- groups, the rate of H pylori colonization was highest in corpus, lower in antrum and lowest in angulus (all P<0.05). The rates of glandular atrophy and intestinal metaplasia were higher and earlier in H pylori-positive patients than those without H pylori infection (both P<0.01). In comparison of gastric ulcer patients with chronic gastritis patients, the rate of glandular atrophy and intestinal metaplasia was higher in H pylori-positive patients with gastric ulcer than in H pylori-positive patients with chronic gastritis (both P<0.01); the rate of glandular atrophy and intestinal metaplasia were also higher in H pylori-negative patients with gastric ulcer than in H pylori-negative patients with chronic gastritis (both P<0.01). Both glandular atrophy and intestinal metaplasia were much more commonly identified in the angulus than in the antrum, lowest in corpus (all P<0.01).

CONCLUSION: Rate of H pylori infection, glandular atrophy and intestinal metaplasia in gastric ulcer were higher than in chronic gastritis in all-different age -groups. Distribution of H pylori colonization is pangastric in the younger patients. It is highest in corpus, lower in antrum and lowest in angulus in the older age groups. Progression of glandular atrophy and intestinal metaplasia seem to have a key role in the distribution of H pylori colonization. H pylori appears to be the most important risk factor for the development of glandular atrophy and intestinal metaplasia, but it is not the only risk.

Esomeprazole 40 mg twice daily in triple therapy and the efficacy of Helicobacter pylori eradication related to CYP2C19 metabolism

AIM

To determine whether an increased dosage of esomeprazole 40 mg twice daily in triple therapy improved the Helicobacter pylori eradication rate for patients with different genotypes of S-mephenytoin 4'-hydroxylase (CYP2C19).

METHODS

Two hundred H. pylori-infected dyspeptic patients were randomized to receive clarithromycin 500 mg twice daily and amoxicillin 1 g twice daily plus either omeprazole 20 mg or esomeprazole 40 mg twice daily for 1 week. Six weeks later, the success of H. pylori eradication was defined. The genotyping of CYP2C19 in each patient was defined as homologous, heterologous extensive metabolizer or poor metabolizer.

RESULTS

The age, gender, drug compliance and proportion of CYP2C19 genotypes were similar between the two groups. The H. pylori eradication rates were also similar between the omeprazole group and the esomeprazole group (intention-to-treat analysis: 79% vs. 86%, P > 0.05; per-protocol analysis: 85% vs. 94%, P > 0.05). For patients classified as homologous extensive metabolizers, the per-protocol H. pylori eradication rate was significantly higher in the esomeprazole group than in the omeprazole group (93% vs. 76%, P < 0.05).

CONCLUSION

Esomeprazole 40 mg twice daily for triple therapy may improve the H. pylori eradication compared to omeprazole-based therapy, but only for homologous extensive metabolizers of CYP2C19.

Antimicrobial effects of antioxidants with and without clarithromycin on Helicobacter pylori

Increasing resistance to currently used antimicrobials has resulted in the evaluation of other agents that have antimicrobial activity against Helicobacter pylori. H. pylori American Type Culture Collection (ATCC) strain 49503 (a toxin-producing strain known to be associated with gastric cancer) was grown, a cell suspension prepared in 2 mL PBS and diluted 10-fold. One hundred microL of this cell suspension was added to vitamin C 0.5%, vitamin E 0.5%, garcinol 100 microg/mL, Protykin (containing 50% trans-resveratrol) 100 microg/mL and garcinol + Protykin 100 microg/mL in Lennox broth, and incubated for 16 h under microaerophilic conditions. Three replicates of 10 microL from each 10(-7) dilution tube were plated, colonies were counted after 16 h, and growth of H. pylori was confirmed by the CLO test. These colony counts were compared to control cultures without the addition of any antioxidants. The experiments were then repeated with the addition of 15 microg/mL of clarithromycin to experimental and control samples. Enhanced killing of H. pylori by 37.6% was noted when vitamin C was added, which increased to 66% when clarithromycin was added, compared to controls (p < 0.05). With garcinol and Protykin alone there was 91.4 and 87% killing of H. pylori, respectively, while a combination of garcinol + Protykin resulted in 90.8% killing compared to controls (p < 0.05). When clarithromycin was added, there was 76.3% increased killing with garcinol alone, 55.3% with Protykin alone, and 73.7% with garcinol + Protykin compared to controls (containing clarithromycin) (p < 0.05). Vitamin E had no effect on H. pylori growth compared to controls. We conclude from this study that some antioxidants such as vitamin C, garcinol and Protykin, but not vitamin E, may have potential as antimicrobial agents against H. pylori.

N-acetylcysteine, a novel treatment for Helicobacter pylori infection

N-Acetylcysteine (NAC), being both a mucolytic agent and a thiol-containing antioxidant, may affect the establishment and maintenance of H. pylori infection within the gastric mucus layer and mucosa. Agar and broth dilution susceptibility tests determined the MIC of H. pylori strain SSI to NAC. H. pylori load in SSI strain-infected C57BL mice was determined as colony forming units per gram of gastric tissue. Gastritis assessment was scored and gastric surface hydrophobicity was determined by contact angle measurement. MICs of NAC were 5 to 10 and 10 to 15 mg/ml using the agar dilution and broth dilution methods, respectively. NAC (120 mg per day for 14 days) reduced the H. pylori load in mice by almost 1 log compared with sham treatment. Pretreatment with NAC (40 mg/day) also significantly reduced the H. pylori load but did not prevent H. pylori colonization. Both H. pylori infection and NAC reduced the surface hydrophobicity of murine gastric mucosa. No significant differences were observed in the gastritis scores of H. felis- or H. pylori-infected mice receiving either NAC or sham treatments. This study demonstrates that NAC inhibits the growth of H. pylori in both agar and broth susceptibility tests and in H. pylori-infected mice. NAC did not alter the severity of H. pylori- or H. felis-induced gastritis.

Induction of cyclooxygenase-2 overexpression in human gastric epithelial cells by Helicobacter pylori involves TLR2/TLR9 and c-Src-dependent nuclear factor-kappaB activation

Gastric epithelial cells were incubated with a panel of clinical isolates of Helicobacter pylori, including nonulcer dyspepsia with gastritis (HS, n = 20), gastric ulcer (HU, n = 20), duodenal ulcer (HD, n = 21), and gastric cancer (HC, n = 20). HC strains induced a higher cyclooxygenase-2 (COX-2) expression than those from HS, HD, and HU. The bacterial virulence factors and the host cellular pathways were investigated. Virulence genes of iceA, vacA, babA2, cagA 3' repeat region, and hrgA failed to show any association with the disease status and COX-2 expression. Methylation-specific polymerase chain reaction revealed HC strains not affecting the methylation status of COX-2 promoter. Nuclear factor (NF)-kappaB, NF-interleukin 6, and cAMP response element were found to be involved in COX-2 induction. We explored a novel NF-kappaB activation pathway. The mutants of TLR2 and TLR9, but not TLR4, inhibited H. pylori-induced COX-2 promoter activity, and neutralizing antibodies for TLR2 and TLR9 abolished H. pylori-induced COX-2 expression. Phosphatidylinositol-specific phospholipase C (PI-PLC), protein kinase C (PKC), and Src inhibitors inhibited COX-2 induction. The dominant-negative mutants of NIK and various IkappaB kinase complexes, including IKKbeta (Y188F), IKKbeta (Y199F), and IKKbeta (FF), inhibited the COX-2 promoter activity. Phosphorylation of GST-IKKbeta (132-206) at Tyr188 and Tyr199 by c-Src was found after H. pylori infection. In summary, H. pylori induces COX-2 expression via activations of NF-kappaB, NF-interleukin 6, the cAMP response element. In NF-kappaB activation, H. pylori acts through TLR2/TLR9 to activate both the cascade of PI-PLCgamma/PKCalpha/c-Src/IKKalpha/beta and the cascade of NIK/IKKalpha/beta, resulting in the IkappaBalpha degradation and the expression of COX-2 gene. The COX-2 overexpression may contribute to the carcinogenesis in patients colonized with these strains.

Gastric transcription profile of Helicobacter pylori infection in the rhesus macaque

Infection with Helicobacter pylori is usually asymptomatic but sometimes progresses to peptic ulcer disease or gastric adenocarcinoma. The development of disease involves both host and bacterial factors. In order to better understand host factors in pathogenesis, we studied the gastric transcription profile of H. pylori infection in the rhesus macaque by using DNA microarrays. Significant changes were found in the expression of genes important for innate immunity, chemokines and cytokines, cell growth and differentiation, apoptosis, structural proteins, and signal transduction and transcription factors. This broad transcription profile demonstrated expected up-regulation of cell structural elements and the host inflammatory and immune response, as well as the novel finding of down-regulation of heat shock proteins. These results provide a unique view of acute H. pylori infection in a relevant animal model system and will direct future studies regarding the host response to H. pylori infection.

Evaluation of stool antigen detection for diagnosis of Helicobacter pylori infection in adults

OBJECTIVE

The aims of this study were to evaluate the performance of Helicobacter pylori stool antigen test in the diagnosis of H. pylori infection.

METHOD

The study included 63 out patients attending the ULB-Lothier Clinic between January 1 and July 31, 2002. They underwent an upper endoscopy, as well as biopsies for histological examination and for culture of H. pylori. Stool samples of these patients were collected either the day of the endoscopy or within 24 hours and tested for H. pylori antigen (HpSA Test)

RESULTS

The mean age of study patients included 29 men and 34 women was 51(+/- :16) years. H. pylori infection was detected in 29 cases (46 %) by culture and histology, and in 31 cases (49.2 %) by detection of the antigen in the feces. In 27 patients, all methods were positive whereas 5 in they provided discrepant results. Compared to the reference methods (culture and histology), the HpSA test had a sensitivity of 96.5% and a specificity of 91.2%. PPV of 90.3% and NPV of 96.8%.

CONCLUSION

The good correlation found between the results of the HpSA test and the methods based on endoscopy supports its use as an alternative to invasive methods of diagnosis of H. pylori infection and therapeutic follow-up.

Does Helicobater pylori initiate or perpetuate immune thrombocytopenic purpura?

To determine the prevalence of Helicobacter pylori (H pylori) infection in North American patients with immune thrombocytopenic purpura (ITP) and the effect of H pylori eradication on the platelet count, a prospective study was performed. Seventy-four patients aged 10 years and older (mean age of 41 years) with chronic ITP and a platelet count below 60 x 10(9)/L were enrolled. H pylori infection was found in 22% of patients by means of a breath test and could not be predicted by gastrointestinal symptoms. H pylori-positive patients (52.5 years of age) were older than H pylori-negative patients (38.5 years of age; P =.0035). Fifteen of the 16 H pylori-positive patients were treated and the bacteria was eradicated in 14 (93%). After 3 months, a significant response (platelet count > 50 x 10(9)/L and doubling the initial count) was observed in only one patient. After a median follow-up of 11.5 months, none of the 14 patients had responded. Ten H pylori-negative patients treated with the same regimen also did not increase their platelet counts. In conclusion, unlike several previous reports, this study does not implicate H pylori in the pathogenesis of ITP since the prevalence of H pylori infection was low and eradication of H pylori did not positively influence the course of the ITP.

Prevalence of cagA and vacA genes in isolates from patients with Helicobacter pylori-associated gastroduodenal diseases in Recife, Pernambuco, Brazil

Geographical differences in the prevalence of Helicobacter pylori genes and their association with disease severity have been identified. This study analyzes the prevalences of the cagA gene and alleles of the vacA gene in H. pylori-associated gastroduodenal diseases in isolates from Recife, PE, Brazil. Gastric biopsy of 61 H. pylori-positive patients were submitted to DNA extraction and gene amplification by polymerase chain reaction. Among the 61 patients, 21 suffered from duodenal ulcer (DU) and 40 from gastritis (GT). The prevalence of H. pylori strains harbouring the cagA gene was higher in the DU group (90.5%) than in the GT group (60%) (p=0.02). The vacA gene was amplified in 56 out of 61 biopsies, of which 43 (76.8%) contained bacteria carrying the s1 allele and 13 (23.2%) the s2. However, the prevalence of the vacA s1 genotyping was the same in either DU or GT group. The majority of the s1-typed strains, 39 (90.7%) out of 43, were subtype s1b. In resume there was a strong association between the H. pylori cagA+ gene and DU. However, there were no differences between the DU and GT groups in relation to the vacA s1 and s2 alleles distribution, albeit the subtype s1b was predominant.