Challenge model for Helicobacter pylori infection in human volunteers

Common occurrence of atrophic gastritis in an ageing non-hospitalised population: an autopsy study

BACKGROUND

Atrophic gastritis-the end stage of chronic gastritis-is an asymptomatic disease due to Helicobacter pylori infection causing decreased vitamin B12 and folate absorption, which may lead to severe haematological and neuropsychological disorders including Alzheimer's disease. The diagnosis requires endoscopy and biopsies from symptomatic patients, explaining why its true prevalence in the population is not well-known.

OBJECTIVE

We aimed to evaluate the prevalence of various stages of chronic gastritis in an autopsy series most closely representing the general population.

SUBJECTS AND METHODS

Gastric mucosa samples were collected prospectively from out-of-hospital deaths included in the Tampere Sudden Death Study (n = 70, mean age 63, age range 22-91 years). Antrum and corpus samples were stained with a H. pylori antibody and staged histopathologically.

RESULTS

Chronic gastritis with or without atrophic changes was detected in 40% of the cases. The proportion of healthy mucosa decreased age-dependently from 71.4% among individuals aged <50 years to 43.5% among the oldest individuals (>70 years), and that of chronic non-atrophic gastritis from 21.4% to 8.7%. In contrast, the prevalence of atrophic gastritis was 27.1% and increased in the age groups from 7.1% to 47.8% (P = .019) among the oldest individuals, showing a strong association (P < .0001) with H. pylori immunopositivity.

CONCLUSIONS

Atrophic gastritis is a common feature of the ageing stomach, which is observed in every second individual aged 70+ years, showing a strong association with H. pylori immunopositivity. Atrophic gastritis may be a more common risk factor in old age for diseases associated with low serum B12 and folate levels than has been previously known.

Causality of Helicobacter pylori infection on eosinophilic esophagitis and potential pathogenesis: a Mendelian randomization study

Background

Observational studies have indicated a possible connection between Helicobacter pylori (H. pylori) infection and eosinophilic esophagitis (EoE), but their causal relationship has yet to be established. To investigate the causal associations between H. pylori infection and EoE, we performed a Mendelian randomization (MR) analysis.

Methods

Firstly, we conducted both univariable and multivariable Mendelian randomization (MR) analyses. Furthermore, a two-step MR was carried out to ascertain the potential underlying pathways of these associations, particularly the involvement of inflammatory cytokines. We employed the inverse-variance weighted (IVW) method as the main analysis in our MR study. To enhance the credibility of the results, we also conducted several sensitivity analyses.

Results

Our study demonstrated a noteworthy correlation between genetically predicted anti-H. pylori IgG antibody levels and a reduced risk of EoE (OR=0.325, 95% CI=0.165-0.643, P value=0.004, adj p value=0.009). No significant causal associations were detected between other H. pylori antibodies and EoE in our study. When it comes to multivariable MR analysis controlling for education attainment, household income, and deprivation individually, the independent causal impact of anti-H. pylori IgG on EoE persisted. Surprisingly, the two-step MR analysis indicated that inflammatory factors (IL-4, IL-5, IL-13, IL-17, and IFN-γ) did not appear to mediate the protective effect of H. pylori infection against EoE.

Conclusion

Findings suggested that among the range of H. pylori-related antibodies, anti-H. pylori IgG antibody is the sole causal factor associated with protection against EoE. Certain inflammatory factors may not be involved in mediating this association. These findings make a significant contribution to advancing our understanding of the pathogenesis of EoE and its evolving etiology.

CCR6+ T helper cells and regulatory T cells in the blood and gastric mucosa during Helicobacter pylori infection

BACKGROUND

Helicobacter pylori (H. pylori) can evade the host's immune response and persist for a long time on the gastric mucosa. T helper (Th) cells appear to be involved in the control of H. pylori bacteria but promote mucosal inflammation. In contrast, regulatory T cells (Tregs) may reduce inflammation but promote H. pylori persistence. CC motif chemokine receptor 6 (CCR6) is involved in the migration of various cells into inflamed gastric mucosa. In this study, we examined CCR6+ Th cells and CCR6+ Tregs during H. pylori infection in humans.

MATERIALS AND METHODS

Isolation of cells from blood and mucosal biopsies, magnetic separation of В cells, CD4+ and CD4+CCR6+CD45RO+ T cells, antigen-specific activation, B cell response in vitro, flow cytometry, determination of CD4+CD25hiFoxP3+ Tregs and various groups of Th cells.

RESULTS

CD4+CCR6+ blood lymphocytes from healthy donors included Th cells and Tregs. These CCR6+ Th cells produced proinflammatory cytokines and also stimulated plasma cell maturation and antibody production in vitro. H. pylori gastritis and peptic ulcer disease were associated with an increase in the number of circulate CD4+CCR6+CD45RO+ cells and the percentage of Th1, Th17 and Th1/17 cells in this lymphocyte subgroup. In H. pylori-positive patients, circulating CD4+CCR6+ cells contained a higher proportion of H. pylori-specific cells compared with their CD4+CCR6- counterparts. H. pylori infection strongly increased the content of CD4+ lymphocytes in the inflamed gastric mucosa, with the majority of these CD4+ lymphocytes expressing CCR6. CD4+CCR6+ lymphocytes from H. pylori-infected stomach included Tregs and in vivo activated T cells, some of which produced interferon-γ without ex vivo stimulation.

CONCLUSION

H. pylori infection causes an increase in the number of mature CD4+CCR6+ lymphocytes in the blood, with a pro-inflammatory shift in their composition and enrichment of the gastric mucosa with CD4+CCR6+ lymphocytes, including CCR6+ Th1 cells and Tregs.

Secrets and lies of host-microbial interactions: MHC restriction and trans-regulation of T cell trafficking conceal the role of microbial agents on the edge between health and multifactorial/complex diseases

Here we critically discuss data supporting the view that microbial agents (pathogens, pathobionts or commensals alike) play a relevant role in the pathogenesis of multifactorial diseases, but their role is concealed by the rules presiding over T cell antigen recognition and trafficking. These rules make it difficult to associate univocally infectious agents to diseases' pathogenesis using the paradigm developed for canonical infectious diseases. (Cross-)recognition of a variable repertoire of epitopes leads to the possibility that distinct infectious agents can determine the same disease(s). There can be the need for sequential infection/colonization by two or more microorganisms to develop a given disease. Altered spreading of infectious agents can determine an unwanted activation of T cells towards a pro-inflammatory and trafficking phenotype, due to differences in the local microenvironment. Finally, trans-regulation of T cell trafficking allows infectious agents unrelated to the specificity of T cell to modify their homing to target organs, thereby driving flares of disease. The relevant role of microbial agents in largely prevalent diseases provides a conceptual basis for the evaluation of more specific therapeutic approaches, targeted to prevent (vaccine) or cure (antibiotics and/or Biologic Response Modifiers) multifactorial diseases.

Helicobacter pylori

Helicobacter pylori (H. pylori) is an important human pathogen etiologically associated with peptic ulcers and gastric cancer. The infection is present in approximately one-half of the world's population. Population-based H. pylori eradiation has confirmed that cure or prevention of the infection produces a marked reduction in gastric cancer and peptic ulcer disease. Antimicrobial therapy has become increasingly ineffective, and complexity and costs of antimicrobial therapy for infected individuals residing in and, immigrating from, the developing world combined with the cost of treatment for cancer make vaccine development a cost-effective alternative. Challenge studies allowed making a "go-no go" decision regarding vaccine effectiveness. We provide detailed protocols regarding challenge strain selection and administration as well as guidance regarding the clinical and laboratory tests used to confirm and monitor experimental infection. Experience shows that reliance of noninvasive methods led to the erroneous conclusion that some subjects were not infected. The current data suggests that histologic assessment of gastric mucosal biopsies may be one of the most sensitive and specific means of assessment of the presence of experimental infection as well as of successful H. pylori eradication. We recommend detailed recommendations for acquiring, processing, embedding, sectioning, and examining the gastric biopsies.

Potentially Infectious Helicobacter pylori in Tap Water in Kermanshah, Western Iran

Background

Although the pathogenesis of Helicobacter pylori is well-defined, the origin and transmission of the bacterium have remained largely unknown. The water transmission hypothesis suggested that water acts as a carrier in oral-fecal transmission, especially in high-prevalence areas. We aimed to evaluate the possible contamination of tap water with infective H. pylori in Kermanshah, Iran from Sep-Oct 2020.

Methods

Tap water samples were collected from varieties of probable high-alert regions and the viability of H. pylori were achieved using culture and real-time PCR techniques (ureA gene expression).

Results

Out of 50 tap water samples, 3 were positive for H. pylori before enrichment and 6 were positive after enrichment by RT qPCR, while H. pylori colonies of two samples were observed on brucella agar plates.

Conclusion

The results of positive samples demonstrated the probable presence of viable H. pylori in tap water samples, showing that tap water distribution systems could be a potential route for H. pylori transmission.

Genetic diversity of the oipA gene among Helicobacter pylori isolates and clinical outcome in Vietnam

Outer inflammatory protein A (OipA), which is encoded by the oipA gene, can induce interleukin-8 secretion in gastric epithelial cells. The functional status of the oipA gene is regulated by the slipped-strand mispairing mechanism based on the CT dinucleotide repeat number in the 5' region. This study aimed to investigate the oipA functional status ("on/off") of Helicobacter pylori (H. pylori) and its association with gastroduodenal diseases in southwestern Vietnam. The cross-sectional study was conducted on 173H. pylori isolates from 173 patients with gastroduodenal diseases. Sanger sequencing was used to determine the functional status of oipA. Multivariable logistic regression analysis was performed to identify the association between oipA status and gastroduodenal diseases. The oipA "on" status accounted for 96% of H. pylori isolates. Twenty-five CT repeat patterns of the oipA 5' signal region were observed, five of which were novel CT repeat patterns. The oipA "on" status was found in 100%, 97.8%, and 86.8% of H. pylori isolates from patients with peptic ulcer, precancerous lesions, and chronic gastritis, respectively (p < 0.01). The oipA "on" status was related to gastric precancerous lesions versus chronic gastritis (adjusted OR = 7.39, 95% CI: 1.35-40.59, p = 0.021) and peptic ulcers versus chronic gastritis (adjusted OR = 12.79, 95% CI: 1.19-1760.32, p = 0.033). Our data show a high prevalence of the oipA "on" status, which was associated with precancerous gastric lesions and peptic ulcers. Moreover, genetic diversity in the number and pattern of CT dinucleotide repeat of oipA among Vietnamese H. pylori strains was identified.

Helicobacter pylori infection

Helicobacter pylori infection causes chronic gastritis, which can progress to severe gastroduodenal pathologies, including peptic ulcer, gastric cancer and gastric mucosa-associated lymphoid tissue lymphoma. H. pylori is usually transmitted in childhood and persists for life if untreated. The infection affects around half of the population in the world but prevalence varies according to location and sanitation standards. H. pylori has unique properties to colonize gastric epithelium in an acidic environment. The pathophysiology of H. pylori infection is dependent on complex bacterial virulence mechanisms and their interaction with the host immune system and environmental factors, resulting in distinct gastritis phenotypes that determine possible progression to different gastroduodenal pathologies. The causative role of H. pylori infection in gastric cancer development presents the opportunity for preventive screen-and-treat strategies. Invasive, endoscopy-based and non-invasive methods, including breath, stool and serological tests, are used in the diagnosis of H. pylori infection. Their use depends on the specific individual patient history and local availability. H. pylori treatment consists of a strong acid suppressant in various combinations with antibiotics and/or bismuth. The dramatic increase in resistance to key antibiotics used in H. pylori eradication demands antibiotic susceptibility testing, surveillance of resistance and antibiotic stewardship.

UreB immunodominant epitope-specific CD8+ T-cell responses were beneficial in reducing gastric symptoms in Helicobacter pylori-infected individuals

BACKGROUND AND AIMS

Although Helicobacter pylori is recognized as an extracellular infection bacterium, it can lead to an increase in the number of CD8⁺ T cells after infection. At present, the characteristics of H. pylori antigen-specific CD8⁺ T cells and the epitope response have not been elucidated. This study was focused on putative protective antigen UreB to detect specific CD8⁺ T-cell responses in vitro and screen for predominant response epitopes.

METHODS

The PBMCs collected from H. pylori-infected individuals were stimulated by UreB peptide pools in vitro to identify the immunodominant CD8⁺ T-cell epitopes. Furthermore, their HLA restriction characteristics were detected accordingly by NGS. Finally, the relationship between immunodominant responses and appearance of gastric symptoms after H. pylori infection was conducted.

RESULTS

UreB-specific CD8⁺ T-cell responses were detected in H. pylori-infected individuals. Three of UreB dominant epitopes (A-2 (UreB_443-451 : GVKPNMIIK), B-4 (UreB_420-428 : SEYVGSVEV), and C-1 (UreB_5-13 : SRKEYVSMY)) were firstly identified and mainly presented by HLA-A*1101, HLA-B*4001 and HLA-C*0702 alleles, respectively. C-1 responses were mostly occurred in H. pylori-infected subjects without gastric symptoms and may alleviate the degree of gastric inflammation.

CONCLUSIONS

The UreB dominant epitope-specific CD8⁺ T-cell response was closely related to the gastric symptoms after H. pylori infection, and the C-1 (UreB_5-13 ) dominant peptides may be protective epitopes.

Clarithromycin-, and metronidazole-resistant Helicobacter pylori isolated from raw and ready-to-eat meat in Mansoura, Egypt

Helicobacter pylori (H. pylori), classified as a class-I carcinogen, is one of the leading medical pathogens of global concern associated mainly with the development of gastric adenocarcinomas and gastric mucosa-associated lymphoid tissue lymphomas; nevertheless, its prevalence in food especially meat and meat products is not fully covered. Additionally, the resistance of H. pylori towards clarithromycin is increasing worldwide and consider the leading cause of H. pylori treatment failure. Thus, the present study was designed to determine the prevalence, molecular characterization, and antimicrobial resistance profiles of clarithromycin-, and metronidazole-resistant H. pylori isolated from raw and ready-to-eat meat samples retailed in Mansoura city, Egypt. Among the 250 samples tested, H. pylori were molecularly confirmed in 40.8 % (49/120) of raw meat products and in 29.2 % (38/130) of ready-to-eat meat products. Precisely, 53.3 % (32/60), 56.7 % (17/30), 40 % (8/20), 55 % (11/20), 60 % (12/20), 13.3 % (4/30), and 15 % (3/20) of raw ground beef, beef burger, beef burger sandwiches, beef shawarma sandwiches, beef kofta sandwiches, beef luncheon, and beef sausage sandwiches, respectively were positive for H. pylori. Of the 204 biochemically-identified H. pylori isolates, 53.9 % (110/204) were molecularly confirmed by PCR through the detection of glmM, cagA, or vacA genes, which were detected at an incidence of 95.5 % (105/110), 77.3 % (85/110), and 20.9 % (23/110) among the isolates, respectively. The antimicrobial sensitivity testing revealed that all of the 110 (100 %) molecularly-confirmed H. pylori isolates were multidrug-resistant (MDR; resistant to four or more antibiotics). Interestingly, 100 % and 61.8 % of H. pylori isolated from raw and ready-to-eat meat were resistant to metronidazole and clarithromycin, respectively which consider alarming results as metronidazole and clarithromycin are the mainstay antibiotics in the treatment of H. pylori infections. Additionally, 94.5 %, 94.5 %, 24.5 %, 23.6 %, and 13.6 % of isolates were resistant to vancomycin, sulphamethoxazole-trimethoprim, imipenem, levofloxacin, and nitrofurantoin, respectively. The widespread contamination of examined raw and ready-to-eat meat product samples with MDR H. pylori isolates could constitute a tremendous public health hazard. Further studies concerning the prevalence and possible methods of elimination of H. pylori in different food categories distributed in the various provinces in Egypt as well as in other countries is required for a better understanding the H. pylori as an emerging foodborne pathogen.

Immune Biology and Persistence of Helicobacter pylori in Gastric Diseases

Helicobacter pylori is a prevalent pathogen, which affects more than 40% of the global population. It colonizes the human stomach and persists in its host for several decades or even a lifetime, if left untreated. The persistent infection has been linked to various gastric diseases, including gastritis, peptic ulcers, and an increased risk for gastric cancer. H. pylori infection triggers a strong immune response directed against the bacterium associated with the infiltration of innate phagocytotic immune cells and the induction of a Th1/Th17 response. Even though certain immune cells seem to be capable of controlling the infection, the host is unable to eliminate the bacteria as H. pylori has developed remarkable immune evasion strategies. The bacterium avoids its killing through innate recognition mechanisms and manipulates gastric epithelial cells and immune cells to support its persistence. This chapter focuses on the innate and adaptive immune response induced by H. pylori infection, and immune evasion strategies employed by the bacterium to enable persistent infection.

Clinical Practice Guidelines of Russian Gastroenterological Association, Scientific Society for the Clinical Study of Human Microbiome, Russian Society for the Prevention of Non-Communicable Diseases, Interregional Association for Clinical Microbiology and Antimicrobial Chemotherapy for <i>H. pylori</i> Diagnostics and Treatment in Adults

Aim: bring to the attention of practitioners indications for anti-Helicobacter therapy, methods and procedure for diagnostics and eradication therapy ofН. pyloriinfection.

Key points. Chronic gastritis caused byН. pyloriinfection, including asymptomatic persons, may be considered as an indication for eradication therapy of Н. pylori as etiological therapy and opportunistic screening for gastric cancer prevention. Indications, for obligatory anti-Helicobacter therapy include peptic ulcer, gastric MALT lymphoma, early gastric cancer (EGC) with endoscopic resection. H. pylori primary diagnostics methods include13C-urea breath test,H. pyloristool antigen lab test, rapid urease test and serological method. The serological method cannot be used after anti-Helicobacter therapy.

In RussiaH. pyloristrains' resistance to clarithromycin does not exceed 15 % in most regional studies. The first line therapy forН. pyloriinfection eradication is the standard triple therapy including a proton pump inhibitor (PPI), clarithromycin and amoxicillin, enhanced with bismuthate tripotassium dicitrate. A classic four-component therapy based on bismuthate tripotassium dicitrate or quadrotherapy without bismuth drug products which includes PPI, amoxicillin, clarithromycin and metronidazole, may be used as alternative to the first line eradication therapy. The standard triple therapy may be prescribed for 14 days only in those regions, where it has been proven to be effective. Quadrotherapy with bismuthate tripotassium dicitrate is also used as main second line therapy in case of standard triple therapy, bismuth enhanced standard triple therapy or combined therapy failure. Another second line therapy includes PPI, levofloxacin and amoxicillin, to which a bismuth-containing drug product may be added. The third line therapy is selected individually based on previously used treatment settings.

Conclusion. In each case ofH. pyloriinfection the decision for eradication therapy should be made, which is especially relevant as eradication ofH. pylorihas been recognized as an effective measure for the prevention of gastric cancer.

Clinical Practice Guidelines of Russian Gastroenterological Association, Scientific Society for the Clinical Study of Human Microbiome, Russian Society for the Prevention of Non-Communicable Diseases, Interregional Association for Clinical Microbiology and Antimicrobial Chemotherapy for <i>H. pylori</i> Diagnostics and Treatment in Adults

Aim: bring to the attention of practitioners indications for anti-Helicobacter therapy, methods and procedure for diagnostics and eradication therapy ofН. pyloriinfection.

Key points. Chronic gastritis caused byН. pyloriinfection, including asymptomatic persons, may be considered as an indication for eradication therapy of Н. pylori as etiological therapy and opportunistic screening for gastric cancer prevention. Indications, for obligatory anti-Helicobacter therapy include peptic ulcer, gastric MALT lymphoma, early gastric cancer (EGC) with endoscopic resection. H. pylori primary diagnostics methods include13C-urea breath test,H. pyloristool antigen lab test, rapid urease test and serological method. The serological method cannot be used after anti-Helicobacter therapy.

In RussiaH. pyloristrains' resistance to clarithromycin does not exceed 15 % in most regional studies. The first line therapy forН. pyloriinfection eradication is the standard triple therapy including a proton pump inhibitor (PPI), clarithromycin and amoxicillin, enhanced with bismuthate tripotassium dicitrate. A classic four-component therapy based on bismuthate tripotassium dicitrate or quadrotherapy without bismuth drug products which includes PPI, amoxicillin, clarithromycin and metronidazole, may be used as alternative to the first line eradication therapy. The standard triple therapy may be prescribed for 14 days only in those regions, where it has been proven to be effective. Quadrotherapy with bismuthate tripotassium dicitrate is also used as main second line therapy in case of standard triple therapy, bismuth enhanced standard triple therapy or combined therapy failure. Another second line therapy includes PPI, levofloxacin and amoxicillin, to which a bismuth-containing drug product may be added. The third line therapy is selected individually based on previously used treatment settings.

Conclusion. In each case ofH. pyloriinfection the decision for eradication therapy should be made, which is especially relevant as eradication ofH. pylorihas been recognized as an effective measure for the prevention of gastric cancer.

Gastric organoids: Advancing the study of H. pylori pathogenesis and inflammation

For decades, traditional in vitro and in vivo models used for the study of Helicobacter pylori infection have relied heavily on the use of gastric cancer cell lines and rodents. Major challenges faced by these methods have been the inability to study cancer initiation in already cancerous cell lines, and the difficulty in translating results obtained in animal models due to genetic differences. These challenges have prevented a thorough understanding of the pathogenesis of disease and slowed the development of cancer therapies and a suitable vaccine against the pathogen. In recent years, the development of gastric organoids has provided great advantages over the traditional in vivo and in vitro models due to their similarities to the human stomach in vivo, their ease of use, and the capacity for long-term culture. This review discusses the advantages and limitations of existing in vivo and in vitro models of H. pylori infection, and how gastric organoids have been applied to study H. pylori pathogenesis, with a focus on how the pathogen interacts with the gastric epithelium, inflammatory processes, epithelial repair, and cancer initiation. The potential applications of organoids to address more complex questions on the role of hormones, vaccine-induced immunity are also discussed.

Pepsinogen II in gastritis and Helicobacter pylori infection

BACKGROUND AND AIM

In the gastric mucosa, pepsinogen II (PgII) is produced/secreted by glands in the mucus-secreting antral and cardia compartments, but also by the chief cells and the oxyntic glands. Increasing PgII serum levels are associated with the whole spectrum of gastric inflammatory diseases, including gastritis induced by Helicobacter pylori (H. pylori). This review critically addresses the clinical value of PgII serology for assessing gastric mucosal inflammation, and as a marker of H. pylori status, in both H. pylori-positive patients and after eradication therapy.

RESULTS

A search in PubMed/Scopus records yielded 39 out of 1190 published scientific studies meeting the selection criteria for this study. In the studies considered, PgII levels were significantly associated with non-atrophic gastric inflammatory lesions (p-values: 0.025-0.0001). H. pylori-positive patients had significantly higher PgII levels than H. pylori-negative individuals (p-values: 0.o5-0.0001). While a significant drop in serum PgII levels is consistently reported in H. pylori-eradicated patients (p-values: from 0.05 to 0.0001), inconsistencies in the related negative and positive predictive values significantly lower the clinical reliability of PgII testing by comparison with other available non-invasive tests.

CONCLUSIONS

PgII serology may provide clinically useful information on gastric inflammatory diseases, particularly if they are non-atrophic. PgII serology is inconsistent, however, for the purposes of distinguishing patients whose H. pylori eradication therapy is successful from those who remain infected.

Epidemiology of Helicobacter pylori

In many countries alike, the time trends of gastric cancer, gastric and duodenal ulcer, ulcerative colitis, Crohn's disease, and colorectal cancer are characterized by similar birth-cohort patterns. Mortality from these diagnoses rose in cohorts born during the 19th century and then fell in subsequent cohorts born during the 20th century.

Clinical Recommendations of Russian Gastroenterological Association and RENDO Endoscopic Society on Diagnosis and Treatment of Gastritis and Duodenitis

Aim.The clinical guidelines are intended to supplement specialty decision-making for improved aid quality in patients with gastritis and duodenitis though acknowledging the latest clinical evidence and principles of evidencebased medicine.Key points.Gastritis is an inflammatory disease of stomach mucosa, with a separate definition of acute and chronic gastritis. Chronic gastritis is a cohort of chronic diseases uniting a typical morphology of persistent inflammatory infiltration, impaired cellular renewal with emergent intestinal metaplasia, atrophy and epithelial dysplasia of gastric mucosa. Oesophagogastroduodenoscopy (OGDS) or high-resolution OGDS with magnified or non-magnified virtual chromoendoscopy, including targeted biopsy for atrophy and intestinal metaplasia grading and neoplasia detection, are recommended to verify gastritis and duodenitis, precancer states and/or gastric mucosal changes. All chronic gastritis patients positive for H. рylori should undergo eradication therapy as aetiological and subsidiary for gastric cancer prevention. Chronic gastritis patients with symptoms of dyspepsia (epigastric pain, burning and congestion, early satiety), also combined with functional dyspepsia, are recommended proton pump inhibitors, prokinetics, rebamipide and bismuth tripotassium dicitrate in symptomatic treatment. With focal restricted intestinal metaplasia, follow-up is not required in most cases, mainly when advanced atrophic gastritis is ruled out in high-quality endoscopy with biopsy. However, a familial history of gastric cancer, incomplete intestinal metaplasia and persistent H. pylori infection render endoscopy monitoring with chromoendoscopy and targeted biopsy desirable once in three years. Patients with advanced atrophic gastritis should have high-quality endoscopy every 3 years, and once in 1–2 years if complicated with a familial history of gastric cancer.Conclusion.The recommendations condense current knowledge on the aetiology and pathogenesis of gastritis and duodenitis, as well as laboratory and instrumental diagnostic techniques, main approaches to aetiological H. pylori eradication and treatment of dyspeptic states.

Two Distinct Etiologies of Gastric Cancer: Infection and Autoimmunity

Gastric cancer is a leading cause of mortality worldwide. The risk of developing gastric adenocarcinoma, which comprises >90% of gastric cancers, is multifactorial, but most associated with Helicobacter pylori infection. Autoimmune gastritis is a chronic autoinflammatory syndrome where self-reactive immune cells are activated by gastric epithelial cell autoantigens. This cause of gastritis is more so associated with the development of neuroendocrine tumors. However, in both autoimmune and infection-induced gastritis, high risk metaplastic lesions develop within the gastric mucosa. This warrants concern for carcinogenesis in both inflammatory settings. There are many similarities and differences in disease progression between these two etiologies of chronic gastritis. Both diseases have an increased risk of gastric adenocarcinoma development, but each have their own unique comorbidities. Autoimmune gastritis is a primary cause of pernicious anemia, whereas chronic infection typically causes gastrointestinal ulceration. Both immune responses are driven by T cells, primarily CD4⁺ T cells of the IFN-γ producing, Th1 phenotype. Neutrophilic infiltrates help clear H. pylori infection, but neutrophils are not necessarily recruited in the autoimmune setting. There have also been hypotheses that infection with H. pylori initiates autoimmune gastritis, but the literature is far from definitive with evidence of infection-independent autoimmune gastric disease. Gastric cancer incidence is increasing among young women in the United States, a population at higher risk of developing autoimmune disease, and H. pylori infection rates are falling. Therefore, a better understanding of these two chronic inflammatory diseases is needed to identify their roles in initiating gastric cancer.

Cytokine Profile of CCR6+ T-Helpers Isolated from the Blood of Patients with Peptic Ulcer Associated with Helicobacter pylori Infection

We previously found that the number of CCR6⁺ T-helpers with the phenotype of effector/effector memory T cells increases in the blood of patients with H. pylori-associated peptic ulcer. The mature phenotype and the expression of the chemokine receptor CCR6, which is involved in migration of lymphocytes to the inflamed mucous membrane of the gastrointestinal tract, suggests that these cells are involved in the immune response observed in this clinical condition. To better understand the pathogenetic role of these cells, it is necessary to study their functional activity, specifically, the production of pro-inflammatory cytokines involved in the pathogenesis of the disease.

The aim of the study was to evaluate changes in the blood level of pro-inflammatory types of mature CCR6⁺ T-helpers in H. pylori-associated peptic ulcer disease.

Milk and dairy products as a possible source of environmental transmission of Helicobacter pylori

Helicobacter pylori (H. pylori) is found worldwide, and it is estimated that more than 50% of the population is infected. The presence of H. pylori in the gastrointestinal tract is associated with the occurrence of serious human diseases such as chronic gastritis, duodenal ulcer or gastric cancer. Therefore, the International Agency for Research on Cancer classified H. pylori as a Group 1 carcinogen in 1994. The routes of H. pylori transmission are not yet precisely known. Many authors agree that humans may become infected by H. pylori through foodstuffs. Milk is one of the basic foods of people of all age categories. Helicobacter pylori has been isolated from milk derived from various livestock, such as cows, sheep, goat, camel or buffalo milk. This review research paper indicates that H. pylori may be present in different types of foods and suggests that consumption of milk and selected dairy products may be a source of H. pylori infection for humans.

Evolved to vary: genome and epigenome variation in the human pathogen Helicobacter pylori

Helicobacter pylori is a Gram-negative, spiral shaped bacterium that selectively and chronically infects the gastric mucosa of humans. The clinical course of this infection can range from lifelong asymptomatic infection to severe disease, including peptic ulcers or gastric cancer. The high mutation rate and natural competence typical of this species are responsible for massive inter-strain genetic variation exceeding that observed in all other bacterial human pathogens. The adaptive value of such a plastic genome is thought to derive from a rapid exploration of the fitness landscape resulting in fast adaptation to the changing conditions of the gastric environment. Nevertheless, diversity is also lost through recurrent bottlenecks and H. pylori's lifestyle is thus a perpetual race to maintain an appropriate pool of standing genetic variation able to withstand selection events. Another aspect of H. pylori's diversity is a large and variable repertoire of restriction-modification systems. While not yet completely understood, methylome evolution could generate enough transcriptomic variation to provide another intricate layer of adaptive potential. This review provides an up to date synopsis of this rapidly emerging area of H. pylori research that has been enabled by the ever-increasing throughput of Omics technologies and a multitude of other technological advances.

Non-Invasive Colorimetric Magneto Loop-Mediated Isothermal Amplification (CM-LAMP) Method for Helicobacter pylori Detection

More than half the world's population is thought to be infected with Helicobacter pylori. Although the majority of infected people are asymptomatic, H. pylori infection may cause gastric ulcers and deadly gastric cancer. Owing to the difficulty and invasiveness of current routine culture and diagnostic methods, a highly sensitive and specific noninvasive assay for H. pylori is of interest. This study highlighted the design and performance of a colorimetric magneto loop-mediated isothermal amplification (CM-LAMP) assay to detect H. pylori in spiked saliva samples. LF primers were coated on magnetic nanoparticles by carbodiimide-induced immobilization and functionally used for solidphase amplification. During the LAMP reaction at 66°C, biotin-tagged FIPs were incorporated into LAMP amplicons. The colorimetric signal developed after the addition of NeutrAvidin horseradish peroxidase conjugate (NA-HRP) and ABTS. None of the tested microorganisms, including closely related bacteria, was shown positive by the CM-LAMP assay except H. pylori isolates. This novel platform was highly specific and 100-fold more sensitive (40 CFU/ml or 0.2 CFU per reaction) than the PCR and conventional LAMP assays for the detection of H. pylori in spiked saliva. Our results demonstrated the feasibility of using this noninvasive molecular diagnostic test to detect H. pylori in saliva samples.

Back to WHAT? The role of research ethics in pandemic times

The Covid-19 pandemic creates an unprecedented threatening situation worldwide with an urgent need for critical reflection and new knowledge production, but also a need for imminent action despite prevailing knowledge gaps and multilevel uncertainty. With regard to the role of research ethics in these pandemic times some argue in favor of exceptionalism, others, including the authors of this paper, emphasize the urgent need to remain committed to core ethical principles and fundamental human rights obligations all reflected in research regulations and guidelines carefully crafted over time. In this paper we disentangle some of the arguments put forward in the ongoing debate about Covid-19 human challenge studies (CHIs) and the concomitant role of health-related research ethics in pandemic times. We suggest it might be helpful to think through a lens differentiating between risk, strict uncertainty and ignorance. We provide some examples of lessons learned by harm done in the name of research in the past and discuss the relevance of this legacy in the current situation.

H. pylori modulates DC functions via T4SS/TNFα/p38-dependent SOCS3 expression

Background

Helicobacter pylori (H. pylori) is a gram-negative bacterium that chronically infects approximately 50% of the world’s human population. While in most cases the infection remains asymptomatic, 10% of infected individuals develop gastric pathologies and 1–3% progress to gastric cancer. Although H. pylori induces severe inflammatory responses, the host’s immune system fails to clear the pathogen and H. pylori can persist in the human stomach for decades. As suppressor of cytokine signaling (SOCS) proteins are important feedback regulators limiting inflammatory responses, we hypothesized that H. pylori could modulate the host’s immune responses by inducing SOCS expression.

Methods

The phenotype of human monocyte-derived DCs (moDCs) infected with H. pylori was analyzed by flow cytometry and multiplex technology. SOCS expression levels were monitored by qPCR and signaling studies were conducted by means of Western blot. For functional studies, RNA interference-based silencing of SOCS1–3 and co-cultures with CD4⁺ T cells were performed.

Results

We show that H. pylori positive gastritis patients express significantly higher SOCS3, but not SOCS1 and SOCS2, levels compared to H. pylori negative patients. Moreover, infection of human moDCs with H. pylori rapidly induces SOCS3 expression, which requires the type IV secretion system (T4SS), release of TNFα, and signaling via the MAP kinase p38, but appears to be independent of TLR2, TLR4, MEK1/2 and STAT proteins. Silencing of SOCS3 expression in moDCs prior to H. pylori infection resulted in increased release of both pro- and anti-inflammatory cytokines, upregulation of PD-L1, and decreased T-cell proliferation.

Conclusions

This study shows that H. pylori induces SOCS3 via an autocrine loop involving the T4SS and TNFα and p38 signaling. Moreover, we demonstrate that high levels of SOCS3 in DCs dampen PD-L1 expression on DCs, which in turn drives T-cell proliferation.

In Vivo Genome and Methylome Adaptation of cag-Negative Helicobacter pylori during Experimental Human Infection

Exceptional genetic diversity and variability are hallmarks of Helicobacter pylori, but the biological role of this plasticity remains incompletely understood. Here, we had the rare opportunity to investigate the molecular evolution during the first weeks of H. pylori infection by comparing the genomes and epigenomes of H. pylori strain BCS 100 used to challenge human volunteers in a vaccine trial with those of bacteria reisolated from the volunteers 10 weeks after the challenge. The data provide molecular insights into the process of establishment of this highly versatile pathogen in 10 different human individual hosts, showing, for example, selection for changes in host-interaction molecules as well as changes in epigenetic methylation patterns. The data provide important clues to the early adaptation of H. pylori to new host niches after transmission, which we believe is vital to understand its success as a chronic pathogen and develop more efficient treatments and vaccines.

Multiple studies have demonstrated rapid bacterial genome evolution during chronic infection with Helicobacter pylori. In contrast, little was known about genetic changes during the first stages of infection, when selective pressure is likely to be highest. Using single-molecule, real-time (SMRT) and Illumina sequencing technologies, we analyzed genome and methylome evolution during the first 10 weeks of infection by comparing the cag pathogenicity island (cagPAI)-negative H. pylori challenge strain BCS 100 with pairs of H. pylori reisolates from gastric antrum and corpus biopsy specimens of 10 human volunteers who had been infected with this strain as part of a vaccine trial. Most genetic changes detected in the reisolates affected genes with a surface-related role or a predicted function in peptide uptake. Apart from phenotypic changes of the bacterial envelope, a duplication of the catalase gene was observed in one reisolate, which resulted in higher catalase activity and improved survival under oxidative stress conditions. The methylomes also varied in some of the reisolates, mostly by activity switching of phase-variable methyltransferase (MTase) genes. The observed in vivo mutation spectrum was remarkable for a very high proportion of nonsynonymous mutations. Although the data showed substantial within-strain genome diversity in the challenge strain, most antrum and corpus reisolates from the same volunteers were highly similar to each other, indicating that the challenge infection represents a major selective bottleneck shaping the transmitted population. Our findings suggest rapid in vivo selection of H. pylori during early-phase infection providing adaptation to different individuals by common mechanisms of genetic and epigenetic alterations.

Interaction Between Ethnicity and Helicobacter pylori Infection in the Occurrence of Reflux Disease

BACKGROUND AND AIMS

Few reports are available to reliably assess the ethnic distribution of Barrett metaplasia and reflux esophagitis. The present study served to analyze the joint influence of Helicobacter pylori infection and patient demographics on the diagnoses of Barrett metaplasia and reflux esophagitis.

METHODS

The Inform Diagnostics database is a national electronic repository of histopathologic records of patients distributed throughout the United States. In a case-control study of 52,096 cases with Barrett metaplasia, 189,235 cases with reflux esophagitis, and 152,322 controls without any signs or symptoms suggestive of gastroesophageal reflux disease, we assessed the influence of age, gender, ethnicity, and H. pylori status on occurrence of Barrett metaplasia or reflux esophagitis.

RESULTS

Barrett metaplasia was less common among East Asians (with odds ratio, 0.48; 95% confidence interval, 0.44-0.53) and Hispanics (0.60, 0.57-0.63) than other ethnic groups living in the United States. Reflux esophagitis was also less common among East Asians (0.86, 0.82-0.90), but more common among Hispanics (1.18, 1.14-1.21). Both types of esophageal disease were associated with a lower prevalence rates of gastric H. pylori infection than controls, with 0.48, 0.44-0.53 for Barrett metaplasia and 0.60, 0.57-0.63 for reflux esophagitis. The prevalence rates of gastric H. pylori and both esophageal diseases were greater in older than younger and male than female patients in all ethnic groups alike.

CONCLUSIONS

Gastric H. pylori infection, ethnicity, gender, and age all influence the occurrence of Barrett metaplasia, and reflux esophagitis.

Upper Gastrointestinal Disease Influences the Occurrence of Inflammatory Bowel Disease

BACKGROUND AND AIMS

Compromise of the gastric acid barrier may facilitate bacterial invasion of the lower intestinal tract and influence the occurrence of inflammatory bowel disease (IBD). Our study tested the associations between histopathologic changes in the upper and lower gastrointestinal tract in patients undergoing bidirectional endoscopy.

METHODS

The Inform Diagnostics database is a national electronic repository of histopathologic records of patients distributed throughout the entire USA. A case-control study among 302,061 patients, of whom 13,943 harbored IBD, evaluated whether the occurrence of Crohn's disease or ulcerative colitis was influenced by the presence of various upper gastrointestinal diagnoses associated with lowered gastric acid output. The influence of individual risk factors on the occurrence of colonic disease was expressed as odds ratios with their 95% confidence intervals.

RESULTS

The odds ratio for Crohn's disease being associated with gastric H. pylori was 0.30 (0.24-0.37), with intestinal metaplasia 0.30 (0.24-0.39), with fundic gland polyps 0.42 (0.35-0.50), with gastric hyperplastic polyps 0.35 (0.23-0.51), with Barrett's metaplasia 0.19 (0.14-0.24), and with reflux esophagitis 0.46 (0.42-0.51). The odds ratio for ulcerative colitis being associated with gastric H. pylori was 0.58 (0.50-0.67), with intestinal metaplasia 0.39 (0.32-0.47), with fundic gland polyps 0.61 (0.53-0.71), with gastric hyperplastic polyps 0.64 (0.49-0.84), with Barrett's metaplasia 0.50 (0.43-0.59), and with reflux esophagitis 0.77 (0.71-0.84).

CONCLUSIONS

A diminished gastric acid barrier function, as evidenced by various upper gastrointestinal diseases associated with lowered gastric acid output, may exert a protective influence against the development of inflammatory bowel disease.

Associations between gastric histopathology and the occurrence of colonic polyps

AIM

Compromise of the gastric acid barrier may facilitate bacterial invasion of the lower intestinal tract and promote the development of colonic neoplasia. Our study aimed to test the associations between histopathological abnormalities of the upper and lower gastrointestinal tract in patients undergoing bidirectional endoscopy.

METHOD

The Inform Diagnostics database is a national electronic repository of histopathological records of patients distributed throughout the USA. A case-control study of 302 061 patients, 163 168 of whom had colonic polyps, evaluated whether the occurrence of colonic polyps was influenced by the presence of the following gastro-oesophageal diagnoses: gastric Helicobacter pylori infection, gastric intestinal metaplasia, fundic gland polyps and gastric hyperplastic polyps. The influence of individual diagnoses on the occurrence of colonic polyps was expressed as odds ratios with their 95% confidence intervals.

RESULTS

The odds ratio for tubular adenomas being associated with gastric H. pylori was 1.53 (1.49-1.58), with intestinal metaplasia 1.65 (1.59-1.71), with fundic gland polyps 1.49 (1.45-1.54) and with gastric hyperplastic polyps 1.85 (1.75-1.96). The odds ratio for sessile serrated polyps being associated with gastric H. pylori was 1.03 (0.96-1.10), with intestinal metaplasia 1.21 (1.13-1.30), with fundic gland polyps 1.79 (1.69-1.89) and with gastric hyperplastic polyps 1.52 (1.35-1.71.

CONCLUSION

A diminished gastric acid barrier function, which occurs in various upper gastrointestinal diseases associated with lowered gastric acid output, may promote the development of colonic neoplasia.

The incidence, aetiology, and adverse clinical consequences of less severe diarrhoeal episodes among infants and children residing in low-income and middle-income countries: a 12-month case-control study as a follow-on to the Global Enteric Multicenter Study (GEMS)

Background

Diarrheal diseases remain a leading cause of illness and death among children younger than 5 years in low-income and middle-income countries. The Global Enteric Multicenter Study (GEMS) has described the incidence, aetiology, and sequelae of medically attended moderate-to-severe diarrhoea (MSD) among children aged 0–59 months residing in censused populations in sub-Saharan Africa and south Asia, where most child deaths occur. To further characterise this disease burden and guide interventions, we extended this study to include children with episodes of less-severe diarrhoea (LSD) seeking care at health centres serving six GEMS sites.

Methods

We report a 1-year, multisite, age-stratified, matched case-control study following on to the GEMS study. Six sites (Bamako, Mali; Manhiça, Mozambique; Basse, The Gambia; Mirzapur, Bangladesh; Kolkata, India; and Bin Qasim Town, Karachi, Pakistan) participated in this study. Children aged 0–59 months at each site who sought care at a sentinel hospital or health centre during a 12-month period were screened for diarrhoea. New (onset after ≥7 diarrhoea-free days) and acute (onset within the previous 7 days) episodes of diarrhoea in children who had sunken eyes, whose skin lost turgor, who received intravenous hydration, who had dysentery, or who were hospitalised were eligible for inclusion as MSD. The remaining new and acute diarrhoea episodes among children who sought care at the same health centres were considered LSD. We aimed to enrol the first eight or nine eligible children with MSD and LSD at each site during each fortnight in three age strata: infants (aged 0–11 months), toddlers (aged 12–23 months), and young children (aged 24–59 months). For each included case of MSD or LSD, we enrolled one to three community control children without diarrhoea during the previous 7 days. From patients and controls we collected clinical and epidemiological data, anthropometric measurements, and faecal samples to identify enteropathogens at enrolment, and we performed a follow-up home visit about 60 days later to ascertain vital status, clinical outcome, and interval growth. Primary outcomes were to characterise, for MSD and LSD, the pathogen-specific attributable risk and population-based incidence values, and to assess the frequency of adverse clinical consequences associated with these two diarrhoeal syndromes.

Findings

From Oct 31, 2011, to Nov 14, 2012, we recruited 2368 children with MSD, 3174 with LSD, and one to three randomly selected community control children without diarrhoea matched to cases with MSD (n=3597) or LSD (n=4236). Weighted adjusted population attributable fractions showed that most attributable cases of MSD and LSD were due to rotavirus, Cryptosporidium spp, enterotoxigenic Escherichia coli encoding heat-stable toxin (with or without genes encoding heat-labile enterotoxin), and Shigella spp. The attributable incidence per 100 child-years for LSD versus MSD, by age stratum, for rotavirus was 22·3 versus 5·5 (0–11 months), 9·8 versus 2·9 (12–23 months), and 0·5 versus 0·2 (24–59 months); for Cryptosporidium spp was 3·6 versus 2·3 (0–11 months), 4·3 versus 0·6 (12–23 months), and 0·3 versus 0·1 (24–59 months); for enterotoxigenic E coli encoding heat-stable toxin was 4·2 versus 0·1 (0–11 months), 5·2 versus 0·0 (12–23 months), and 1·1 versus 0·2 (24–59 months); and for Shigella spp was 1·0 versus 1·3 (0–11 months), 3·1 versus 2·4 (12–23 months), and 0·8 versus 0·7 (24–59 months). Participants with both MSD and LSD had significantly more linear growth faltering than controls at follow-up.

Interpretation

Inclusion of participants with LSD markedly expands the population of children who experience adverse clinical and nutritional outcomes from acute diarrhoeal diseases. Since MSD and LSD have similar aetiologies, interventions targeting rotavirus, Shigella spp, enterotoxigenic E coli producing heat-stable toxin, and Cryptosporidium spp might substantially reduce the diarrhoeal disease burden and its associated nutritional faltering.

Funding

Bill & Melinda Gates Foundation.

The frequency of circulating integrin α4β7+ cells correlates with protection against Helicobacter pylori infection in immunized mice

BACKGROUND

Chronic Helicobacter pylori infection is the cause of peptic ulcers in a subpopulation of individuals and a risk factor for the development of gastric cancer. A vaccine against H pylori infection can prevent the acquisition of the infection and protect against reinfections. Clinical trials to date evaluating the efficacy of H pylori vaccines in human challenge models have shown moderate to poor protection with difficulties in predicting efficacy. Thus, while further studies are needed to design an effective vaccine, we also need to find relevant correlates for vaccine efficacy.

OBJECTIVE

To find immune correlates to vaccine efficacy, the frequencies of neutrophils, eosinophils and inflammatory monocytes and CD4⁺ T-cell memory and mucosa homing integrin α4β7⁺ cells were assessed by flow cytometry in the blood of mice after vaccination.

MATERIALS AND METHODS

H pylori antigens and cholera toxin or the multiple mutant CT (mmCT) were administered via the sublingual (SL) and intragastric route (IG). The vaccinated mice were infected with H pylori strain SS1 bacteria, and colonization in the stomach and immune responses were evaluated.

RESULTS

The H pylori vaccine was effective in reducing bacterial load in the stomach of mice and enhancing immune responses compared to unvaccinated infection controls. In the blood of mice after SL or IG route of vaccination, we observed changes in frequencies of innate and adaptive immune cell subsets compared to infection controls. Remarkably, the frequency of circulating mucosal homing α4β7⁺ CD4⁺ T cells after vaccination correlated with low bacterial load in the stomach of individual mice irrespective of the immunization route.

CONCLUSIONS

Our study shows that the innate and adaptive immune cell subsets can be measured in the blood after vaccination and that increased frequency of α4β7⁺ CD4⁺ in the blood after immunization could be used as a predictive marker for the efficacy of vaccine against H pylori infection.

Immunity and Vaccine Development Against Helicobacter pylori

Helicobacter pylori is a highly-adapted gastrointestinal pathogen of humans and the immunology of this chronic infection is extremely complex. Despite the availability of antibiotic therapy, the global incidence of H. pylori infection remains high, particularly in low to middle-income nations. Failure of therapy and the spread of antibiotic resistance among the bacteria are significant problems and provide impetus for the development of new therapies and vaccines to treat or prevent gastric ulcer, and gastric carcinoma. The expansion of knowledge on gastric conventional and regulatory T cell responses, and the role of T_H17 in chronic gastritis from studies in mouse models and patients have provided valuable insights into how gastritis is initiated and maintained. The development of human challenge models for testing candidate vaccines has meant a unique opportunity to study acute infection, but the field of vaccine development has not progressed as rapidly as anticipated. One clear lesson learned from previous studies is that we need a better understanding of the immune suppressive mechanisms in vivo to be able to design vaccine strategies. There is still an urgent need to identify practical surrogate markers of protection that could be deployed in future field vaccine trials. Important developments in our understanding of the chronic inflammatory response, progress and problems arising from human studies, and an outlook for the future of clinical vaccine trials will be discussed.

Helicobacter pylori eradication in dyspepsia: New evidence for symptomatic benefit

A causal relationship between Helicobacter pylori (H. pylori) infection and functional dyspepsia (FD) is well established in a subset of infected patients. In the Kyoto and Maastricht/Florence consensus reports H. pylori-associated dyspepsia is defined as an independent entity distinct from FD. H. pylori eradication is therefore the most cost-effective approach for infected patients with dyspeptic symptoms and superior to other medical therapies, such as Proton Pump Inhibitors. The therapeutic gain of H.pylori eradication for symptom relief compared to other therapeutic options is significant with the number needed to benefit of 12. Furthermore H.pylori cures chronic gastritis except in severe cases of atrophic gastritis and may prevent severe complications attributable to the infection. Several pathophysiological mechanisms are suggested for the generation of symptoms and are related to the distinct topographic expression and degree of gastric inflammation as well as changes of gastric acid secretion, gastrointestinal motility and visceral hypersensitivity.

Inflammation, Immunity, and Vaccine Development for the Gastric Pathogen Helicobacter pylori

It has been over 30 years since a link was established between H. pylori infection of the gastric mucosa and the development of chronic gastric diseases. Research in rodent models supported by data from human tissue demonstrated that the host immune response to H. pylori is limited by host regulatory T cells. Immunization has been shown to induce a potent Th1- and Th17-mediated immune response capable of eradicating or at least significantly reducing the bacterial load of H. pylori in the stomach in small animal models. These results have not translated well to humans. Clinical trials employing many of the strategies used in rodents for oral immunization including the use of a mucosal adjuvant such as Escherichia coli LT or delivery by attenuated enteric bacteria have failed to limit H. pylori infection and have highlighted the potential toxicity of exotoxin-based mucosal adjuvants. A recent study, however, utilizing a recombinant fusion protein of H. pylori urease and the subunit B of E. coli LT, was performed on over 4000 children. Efficacy of over 70% was demonstrated against naturally acquired infection compared to control volunteers one year post-immunization. Efficacy was reduced, but still above 50% at three years. This study provided new insight into the strategies for developing an improved vaccine for widespread use in countries with high infection rates and where gastric cancer (GC) remains one of the most common causes of death due to cancer.

Helicobacter Pylori Detection in Shellfish: A Real-Time Quantitative Polymerase Chain Reaction Approach

Shellfish is a highly valuated natural food product that is usually consumed minimally processed. Some foodborne pathogens have been associated to marine products and isolated from aquatic environments. Helicobacter pylori emerges as one of the most concerning human pathogens associated to water and, thereby, it could be present in raw and slightly treated marine food products. The present research work aimed to detect the presence of H. pylori in Spanish commercial samples of shellfish (mussels, clams, and cockles) by means of a quantitative real-time polymerase chain reaction (qPCR) approach based on the vacuolating cytotoxin A (vacA) gene specificity. Putative H. pylori amplicons were confirmed by sequencing. qPCR was positive for 12 out of the 100 samples, being 67% (8/12) from mussels, 25% (3/12) from clams, and only 8% (1/12) from cockles. After sequencing, three of the amplicons showed 97-99% homology with the H. pylori vacA gene. Quantitative results indicate that the levels of contamination remained below 102 log10 colony forming units per mL (CFU/mL). The present research shows for the first time the effectiveness of the optimized qPCR in the identification of potentially H. pylori contaminated shellfish products. Our results confirm the presence of H. pylori in shellfish from the Spanish western seacoast and verify the possible relationship between the presence of H. pylori in seawater and the role of contaminated seafoods as vehicles of H. pylori entrance into the food chain.

Monitoring levels of viable Helicobacter pylori in surface water by qPCR in Northeast Spain

Helicobacter pylori infection is a risk factor for chronic active gastritis, peptic ulcers, gastric carcinoma and lymphoma. Although the infection may be acquired through different transmission routes, the presence and viability of H. pylori in water sources are not well known. Therefore, the aim of our study was to analyse the viability of H. pylori cells in urban surface waters collected at the Vallparadís public park in Terrassa, Barcelona, Spain. The water samples were analysed by viability quantitative polymerase chain reaction (qPCR) using propidium monoazide and specific primers for the H. pylori vacuolating cytotoxin (vacA gene). Viable H. pylori were found in 91.3% of the samples analysed, with an average concentration of 3.46 ± 1.06 log cell 100 mL^-1. Our work proves a quick and simple procedure for evaluating viable H. pylori cells in environmental samples by qPCR. Furthermore, the results provide evidence that urban surface waters may contain considerable levels of viable H. pylori cells, thus indicating they are a potential source of infection, which represents a public health concern.

Role of polymorphisms in genes that encode cytokines and Helicobacter pylori virulence factors in gastric carcinogenesis

The Helicobacter pylori (H. pylori) infection is a determinant factor in gastric cancer (GC) development. However, the infection outcomes are variable and depend on both host and bacterial characteristics. Some host cytokines such as interleukin (IL)-1β, IL-1Ra, IL-8, IL-10 and tumor necrosis factor-α play important roles in the host immune system response to the pathogen, in the development of gastric mucosal lesions and in cell malignant transformation. Therefore, these host factors are crucial in neoplastic processes. Certain polymorphisms in genes that encode these cytokines have been associated with an increased risk of GC. On the other hand, various virulence factors found in distinct H. pylori bacterial strains, including cytotoxin-associated antigen A, vacuolating cytotoxin, duodenal ulcer promoting gene A protein, outer inflammatory protein and blood group antigen binding adhesin, have been associated with the pathogenesis of different gastric diseases. The virulent factors mentioned above allow the successful infection by the bacterium and play crucial roles in gastric mucosa lesions, including malignant transformation. Moreover, the role of host polymorphisms and bacterial virulence factors in gastric carcinogenesis seems to vary among different countries and populations. The identification of host and bacterium factors that are associated with an increased risk of GC development may be useful in determining the prognosis of infection in patients, what could help in clinical decision-making and in providing of an optimized clinical approach.

Decreased risk for microscopic colitis and inflammatory bowel disease among patients with reflux disease

AIM

Previous studies have found an increased risk for microscopic colitis (MC) associated with proton pump inhibitors. In patients with ulcerative colitis (UC) or Crohn's disease (CD), proton pump inhibitors have been associated with an increased risk for IBD flares and impaired outcomes. The aim of this study was to test the epidemiological associations between gastro-oesophageal reflux disease (GERD) and MC, UC or CD in a large database.

METHOD

The Miraca Life Sciences Database is a national electronic repository of histopathological records of patients distributed throughout the entire USA. A case-control study evaluated whether the presence of Barrett's metaplasia, erosive oesophagitis on endoscopy or histological signs of reflux oesophagitis, clinical diagnosis of GERD or any GERD type affected the occurrence of MC, UC or CD among 228 506 subjects undergoing bidirectional endoscopy. Multivariate logistic regression analyses were used to calculate ORs and their 95% CI for the risk of MC, UC or CD associated with various types of GERD and were adjusted for age, sex and presence of Helicobacter pylori.

RESULTS

The analysis revealed an inverse relationship between GERD and different types of inflammatory bowel disease. The inverse relationships applied similarly to MC (mean = 0.62, 95% CI: 0.58-0.66), UC (mean = 0.89, 95% CI: 0.81-0.97) and CD (mean = 0.76, 95% CI: 0.69-0.85). It also applied to different forms of GERD, with a trend towards more pronounced inverse relationships associated with Barrett's metaplasia or erosive oesophagitis than clinical diagnosis of GERD.

CONCLUSION

Gastro-oesophageal reflux disease is inversely associated with all forms of inflammatory bowel disease, such as MC, UC, or CD.

Experimental infection of human volunteers

Controlled human infection (CHI) trials, in which healthy volunteers are experimentally infected, can accelerate the development of novel drugs and vaccines for infectious diseases of global importance. The use of CHI models is expanding from around 60 studies in the 1970s to more than 120 publications in this decade, primarily for influenza, rhinovirus, and malaria. CHI trials have provided landmark data for several registered drugs and vaccines, and have generated unprecedented scientific insights. Because of their invasive nature, CHI studies demand critical ethical review according to established frameworks. CHI-associated serious adverse events are rarely reported. Novel CHI models need standardised safety data from comparable CHI models to facilitate evidence-based risk assessments, as well as funds to produce challenge inoculum according to regulatory requirements. Advances such as the principle of controlled colonisation, the expansion of models to endemic areas, and the use of genetically attenuated strains will further broaden the scope of CHI trials.

Status of vaccine research and development for Helicobacter pylori

Gastric adenocarcinoma is globally the third leading cause of death due to malignancy, with the bulk of this disease burden being suffered by low and middle income countries (LMIC), especially in Asia. The majority of these cancers develop as a result of a chronic gastritis that arises in response to infection with the stomach-dwelling bacterium, Helicobacter pylori. A vaccine against this pathogen would therefore be a powerful tool for preventing gastric adenocarcinoma. However, notwithstanding a proof-of-concept that vaccination can protect children from acquisition of H. pylori infection, there are currently no advanced vaccine candidates with only a single vaccine in Phase I clinical trial. Further, the development of a vaccine against H. pylori is not a current strategic priority of major pharmaceutical companies despite the large global disease burden. Given the involvement of such companies is likely to be critical for late stage development, there is therefore a need for an increased appreciation of the burden of this disease in LMIC and more investment to reinvigorate research in H. pylori vaccine Research and Development.

An assessment of drinking water contamination with Helicobacter pylori in Lima, Peru

BACKGROUND

Helicobacter pylori is a gut bacterium that is the primary cause of gastric cancer. H. pylori infection has been consistently associated with lack of access to sanitation and clean drinking water. In this study, we conducted time-series sampling of drinking water in Lima, Peru, to examine trends of H. pylori contamination and other water characteristics.

MATERIALS AND METHODS

Drinking water samples were collected from a single faucet in Lima's Lince district 5 days per week from June 2015 to May 2016, and pH, temperature, free available chlorine, and conductivity were measured. Quantities of H. pylori in all water samples were measured using quantitative polymerase chain reaction. Relationships between the presence/absence and quantity of H. pylori and water characteristics in the 2015-2016 period were examined using regression methods accounting for the time-series design.

RESULTS

Forty-nine of 241 (20.3%) of drinking water samples were contaminated with H. pylori. Statistical analyses identified no associations between sampling date and the likelihood of contamination with H. pylori. Statistically significant relationships were found between lower temperatures and a lower likelihood of the presence of H. pylori (P < .05), as well as between higher pH and higher quantities of H. pylori (P < .05).

CONCLUSIONS

This study has provided evidence of the presence of H. pylori DNA in the drinking water of a single drinking water faucet in the Lince district of Lima. However, no seasonal trends were observed. Further studies are needed to determine the presence of H. pylori in other drinking water sources in other districts in Lima, as well as to determine the viability of H. pylori in these water sources. Such studies would potentially allow for better understanding and estimates of the risk of infection due to exposure to H. pylori in drinking water.

When is Helicobacter pylori acquired in populations in developing countries? A birth-cohort study in Bangladeshi children

Helicobacter pylori colonization is prevalent throughout the world, and is predominantly acquired during childhood. In developing countries, >70% of adult populations are colonized with H. pylori and >50% of children become colonized before the age of 10 years. However, the exact timing of acquisition is unknown. We assessed detection of H. pylori acquisition among a birth cohort of 105 children in Mirzapur, Bangladesh. Blood samples collected at time 0 (cord blood), and at 6, 12, 18, and 24 months of life were examined for the presence of IgG and IgA antibodies to whole cell H. pylori antigen and for IgG antibodies to the CagA antigen using specific ELISAs and immunoblotting. Breast milk samples were analyzed for H. pylori-specific IgA antibodies. Cord blood was used to establish maternal colonization status. H. pylori seroprevalence in the mothers was 92.8%. At the end of the two-year follow-up period, 50 (47.6%) of the 105 children were positive for H. pylori in more than one assay. Among the colonized children, CagA prevalence was 78.0%. A total of 58 children seroconverted: 50 children showed persistent colonization and 8 (7.6%) children showed transient seroconversion, but immunoblot analysis suggested that the transient seroconversion observed by ELISA may represent falsely positive results. Acquisition of H. pylori was not influenced by the mother H. pylori status in serum or breastmilk. In this population with high H. pylori prevalence, we confirmed that H. pylori in developing countries is detectable mainly after the first year of life.

Increased Risk for Colon Polyps in Patients with Reflux Disease

BACKGROUND

Previous studies have found an increased risk for colonic neoplasm in patients with Barrett's esophagus. It is unknown whether such risk applies similarly to other types of gastroesophageal reflux disease (GERD).

AIMS

To test whether GERD represents a risk factor for the occurrence of colon polyps.

METHODS

The Miraca Life Sciences Database is a large national electronic repository of histopathologic records of patients distributed throughout the entire USA. A case-control study evaluated whether presence of (1) Barrett's metaplasia, (2) erosive esophagitis on endoscopy or histologic signs of reflux esophagitis, (3) clinical diagnosis of GERD, (4) any type of GERD affected the occurrence hyperplastic polyps (HP), sessile serrated adenomas/polyps (SSA/P), or tubular adenomas (TA) among 228,506 subjects undergoing bidirectional endoscopy. Multivariate logistic regression analyses were used to calculate odds ratios and their 95% confidence intervals for the risk of HP, TA or SSA/P associated with various types of GERD and adjusted for age, sex, and presence of H. pylori.

RESULTS

The analysis revealed positive associations between GERD and all types of colon polyps. These associations applied similarly to HP (1.47, 1.44-1.50), TA (1.30, 1.27-1.32), and SSA/P (1.52, 1.46-1.58). They also applied to different forms of GERD, showing a trend toward stronger associations, that is higher odds ratios, with Barrett's metaplasia or erosive esophagitis than clinical diagnosis of GERD.

CONCLUSION

All types of GERD represent a risk factor for the occurrence of different colon polyps, such as HP, TA, or SSA/P.

Regulation of low-density lipoprotein cholesterol by intestinal inflammation and the acute phase response

Systemic inflammation, induced by disease or experimental intervention, is well established to result in elevated levels of circulating triglycerides, and reduced levels of high-density lipoprotein-cholesterol (HDL-C), in most mammalian species. However, the relationship between inflammation and low-density lipoprotein-cholesterol (LDL-C) concentrations is less clear. Most reports indicate that systemic inflammation, as observed during sepsis or following high dose experimental endotoxaemia, lowers total, and LDL-C in man. However, isolated reports have suggested that certain inflammatory conditions are associated with increased LDL-C. In this review, we summarize the emerging evidence that low-grade inflammation specifically of intestinal origin may be associated with increased serum LDL-C levels. Preliminary insights into potential mechanisms that may mediate these effects, including those connecting inflammation to trans-intestinal cholesterol efflux (TICE), are considered. We conclude that this evidence supports the potential downregulation of major mediators of TICE by inflammatory mediators in vitro and during intestinal inflammation in vivo. The TICE-inflammation axis therefore merits further study in terms of its potential to regulate serum LDL-C, and as a readily druggable target for hypercholesterolaemia.

The ethnic distribution of sessile serrated polyps in the United States is inversely associated with Helicobacter pylori prevalence

AIM

Little is known about the epidemiology of sessile serrated polyps (SSP). Our study aimed to investigate the influence of Helicobacter pylori gastritis and patient demographic characteristics (age, gender, ethnicity) on the prevalence of SSP using a large national database of patients undergoing bi-directional endoscopy.

METHOD

De-identified patient data were extracted from the Miraca Life Sciences electronic database of histopathological reports. Using multivariate logistic regression analysis, the influence of H. pylori gastritis and demographic characteristics on the occurrence of SSP were expressed as odds ratios (OR) with their 95% confidence intervals (CI).

RESULTS

The total study population comprised 228 506 subjects, of whom 28 890 carried a diagnosis of H. pylori gastritis and 11 285 SSP. Age (OR 4.35, 95% CI: 3.82-4.96), female gender (0.92, 0.88-0.95) and H. pylori gastritis (0.94, 0.88-0.99) exerted the strongest influence on the occurrence of SSP. In comparison with the population comprising Caucasians and African Americans, SSP were less common among subjects of Hispanic (0.67, 0.62-0.73), East Asian (0.59, 0.50-0.69), Indian (0.43, 0.27-0.64) or Middle Eastern descent (0.61, 0.41-0.87). All these ethnic subgroups were also characterized by a higher prevalence of H. pylori than the comparison group. A low prevalence of H. pylori was significantly associated with a high prevalence of SSP (R²  = 0.82, P < 0.001).

CONCLUSION

The prevalence of SSP within the United States is characterized by a marked ethnic variation. The inverse correlation between the prevalence of H. pylori and SSP suggests that gastric infection with H. pylori may be partly responsible for the observed ethnic distribution of SSP.

Gastric TFF1 Expression from Acute to Chronic Helicobacter Infection

TFF1, a mucin-associated secreted peptide of gastric mucous cells, is known as a protective agent for stomach epithelium under different stimuli, but its role upon Helicobacter infection is still not clear. In this paper we characterized TFFs expression, with particular attention to TFF1, under Helicobacter infection in gastric cell lines. A mouse model was used to distinguish TFF1 mRNA expression between acute and chronic stages of Helicobacter infection. Our results show that TFF1 expression is induced in infected cells; in addition, the inflammatory response upon Helicobacter infection is inversely associated to pre-existing TFF1 protein levels. In infected mice, TFF1 is initially upregulated in gastric antrum in the acute phase of infection, along with IL-1β and IL-6. Then, expression of TFF1 is gradually silenced when the infection becomes chronic and IFN-γ, CXCL5, and CXCL15 reach higher levels. Our data suggest that TFF1 might help cells to counteract bacteria colonization and the development of a chronic inflammation.

The Human Stomach in Health and Disease: Infection Strategies by Helicobacter pylori

Helicobacter pylori is a bacterial pathogen which commonly colonizes the human gastric mucosa from early childhood and persists throughout life. In the vast majority of cases, the infection is asymptomatic. H. pylori is the leading cause of peptic ulcer disease and gastric cancer, however, and these outcomes occur in 10-15% of those infected. Gastric adenocarcinoma is the third most common cause of cancer-associated death, and peptic ulcer disease is a significant cause of morbidity. Disease risk is related to the interplay of numerous bacterial host and environmental factors, many of which influence chronic inflammation and damage to the gastric mucosa. This chapter summarizes what is known about health and disease in H. pylori infection, and highlights the need for additional research in this area.

The influence of Helicobacter pylori on the ethnic distribution of esophageal eosinophilia

BACKGROUND

Environmental factors associated with ethnicity may contribute to the occurrence of eosinophilic esophagitis. Our study aimed to investigate the influence of Helicobacter pylori on the ethnic variation of esophageal eosinophilia in a large national sample of patients undergoing esophago-gastro-duodenoscopy.

METHODS

The Miraca Life Sciences Database is an electronic repository of histopathologic patient records. A case-control study evaluated the influence of ethnicity on the occurrence of esophageal eosinophilia and how age, gender, and histologic diagnosis of H. pylori modify this relationship.

RESULTS

The total study population comprised 596 479 subjects, of whom 25 969 harbored a diagnosis of esophageal eosinophilia. Young age, male sex, and H. pylori infection in declining order exerted the strongest influence on the occurrence of esophageal eosinophilia. In comparison with the population comprising of Caucasians and African-Americans, esophageal eosinophilia was less common among patients of African (OR=0.10, 95% CI=0.01-0.46), Middle Eastern (0.22, 0.15-0.31), East Asian (0.32, 0.26-0.38), Indian (0.28, 0.21-0.37), Hispanic (0.40, 0.37-0.43), or Jewish descent (0.58, 0.51-0.66), but more common among patients of Northern European descent (1.25, 1.07-1.45). With the exception of Northern Europeans, all ethnic subgroups were characterized by a higher prevalence of H. pylori than the comparison group. A low prevalence of H. pylori was significantly associated with a high prevalence of esophageal eosinophilia (R² =0.90, P<.001).

CONCLUSION

Esophageal eosinophilia prevalence markedly varies by patient ethnicity. As there is a strong inverse correlation between H. pylori and esophageal eosinophilia, H. pylori infection may be in part responsible for the observed ethnic distribution of esophageal eosinophilia.

Immunoprevalence to Six Waterborne Pathogens in Beachgoers at Boquerón Beach, Puerto Rico: Application of a Microsphere-Based Salivary Antibody Multiplex Immunoassay

Waterborne infectious diseases are a major public health concern worldwide. Few methods have been established that are capable of measuring human exposure to multiple waterborne pathogens simultaneously using non-invasive samples such as saliva. Most current methods measure exposure to only one pathogen at a time, require large volumes of individual samples collected using invasive procedures, and are very labor intensive. In this article, we applied a multiplex bead-based immunoassay capable of measuring IgG antibody responses to six waterborne pathogens simultaneously in human saliva to estimate immunoprevalence in beachgoers at Boquerón Beach, Puerto Rico. Further, we present approaches for determining cutoff points to assess immunoprevalence to the pathogens in the assay. For the six pathogens studied, our results show that IgG antibodies against antigens from noroviruses GI.I and GII.4 were more prevalent (60 and 51.6%, respectively) than Helicobacter pylori (21.4%), hepatitis A virus (20.2%), Campylobacter jejuni (8.7%), and Toxoplasma gondii (8%) in the saliva of the study participants. The salivary antibody multiplex immunoassay can be used to examine immunoprevalence of specific pathogens in human populations.

Interaction of Ethnicity and H. pylori Infection in the Occurrence of Microscopic Colitis

BACKGROUND

Previous studies found that microscopic colitis is inversely associated with Helicobacter pylori infection and that microscopic colitis is characterized by a marked ethnic variation.

AIM

The aim of the present study was to test whether an underlying ethnic variation of H. pylori infection is responsible for the ethnic variation of microscopic colitis.

METHODS

The Miraca Life Sciences Database is a large national electronic repository of histopathologic records of patients distributed throughout the entire USA. A cross-sectional study evaluated the influence of age, gender, ethnicity, and histologic diagnosis of H. pylori on the occurrence of microscopic colitis among subjects who underwent esophago-gastro-duodenoscopies plus colonoscopy.

RESULTS

The total study population comprised 228,506 subjects, of whom 28,890 carried a diagnosis of H. pylori gastritis and 3460 microscopic colitis. Female sex, old age, and H. pylori infection exerted the strongest influence on the occurrence of microscopic colitis. In comparison with the population comprising Caucasians and African-Americans, microscopic colitis was less common among subjects of Hispanic (0.34, 0.27-0.47), East Asian (0.13, 0.06-0.22), Indian (0.31, 0.10-0.73), or Middle Eastern descent (0.28, 0.07-0.74). All these ethnic subgroups were also characterized by a higher prevalence of H. pylori than the comparison group. A low prevalence of H. pylori was significantly associated with a high prevalence of microscopic colitis (R ² = 0.91, p < 0.001).

CONCLUSION

Ethnic variations in the gastric infection with H. pylori may be partly responsible for the observed ethnic distribution of microscopic colitis.