Extragastric diseases associated with Helicobacter pylori infection

Helicobacter pylori Outer Membrane Proteins and Virulence Factors: Potential Targets for Novel Therapies and Vaccines

Helicobacter pylori is a gastric oncopathogen that infects over half of the world's human population. It is a Gram-negative, microaerophilic, helix-shaped bacterium that is equipped with flagella, which provide high motility. Colonization of the stomach is asymptomatic in up to 90% of people but is a recognized risk factor for developing various gastric disorders such as gastric ulcers, gastric cancer and gastritis. Invasion of the human stomach occurs via numerous virulence factors such as CagA and VacA. Similarly, outer membrane proteins (OMPs) play an important role in H. pylori pathogenicity as a means to adapt to the epithelial environment and thereby facilitate infection. While some OMPs are porins, others are adhesins. The epithelial cell receptors SabA, BabA, AlpA, OipA, HopQ and HopZ have been extensively researched to evaluate their epidemiology, structure, role and genes. Moreover, numerous studies have been performed to seek to understand the complex relationship between these factors and gastric diseases. Associations exist between different H. pylori virulence factors, the co-expression of which appears to boost the pathogenicity of the bacterium. Improved knowledge of OMPs is a major step towards combatting this global disease. Here, we provide a current overview of different H. pylori OMPs and discuss their pathogenicity, epidemiology and correlation with various gastric diseases.

Association between Helicobacter pylori Infection and Chronic Urticaria: A Meta-Analysis

Background. Some studies have shown the possible involvement of Helicobacter pylori (H. pylori) infection in chronic urticaria, but the relationship remains controversial. The aim of this meta-analysis was to quantitatively assess the association between H. pylori infection and chronic urticaria. Methods. Observational studies comparing the prevalence of H. pylori infection in patients with chronic urticaria and control subjects were identified through a systematic search in MEDLINE and EMBASE up to July 2014. H. pylori infection was confirmed by serological or nonserological tests. For subgroup analyses, studies were separated by region, publication year, and H. pylori detection method to screen the potential factors resulting in heterogeneity. Results. 16 studies involving 965 CU cases and 1235 controls were included. Overall, the prevalence of H. pylori infection was higher in urticarial patients than in controls (OR = 1.66; 95% CI: 1.12–2.45; P = 0.01). This result persisted in subanalysis of nine high-quality studies (OR = 1.36; 95% CI: 1.03–1.80; P = 0.03). Subgroup analysis showed that detection method of H. pylori is also a potential influential factor for the overall results. Conclusions. Our present meta-analysis suggests that H. pylori infection is significantly, though weakly, associated with an increased risk of chronic urticaria.

Helicobacter pylori infection and extragastric disorders in children: a critical update

Helicobacter pylori (H. pylori) is a highly prevalent, serious and chronic infection that has been associated causally with a diverse spectrum of extragastric disorders including iron deficiency anemia, chronic idiopathic thrombocytopenic purpura, growth retardation, and diabetes mellitus. The inverse relation of H. pylori prevalence and the increase in allergies, as reported from epidemiological studies, has stimulated research for elucidating potential underlying pathophysiological mechanisms. Although H. pylori is most frequently acquired during childhood in both developed and developing countries, clinicians are less familiar with the pediatric literature in the field. A better understanding of the H. pylori disease spectrum in childhood should lead to clearer recommendations about testing for and treating H. pylori infection in children who are more likely to develop clinical sequelae. A further clinical challenge is whether the progressive decrease of H. pylori in the last decades, abetted by modern clinical practices, may have other health consequences.

Long-term effects of clearing Helicobacter pylori on growth in school-age children

BACKGROUND

A new Helicobacter pylori infection affects growth velocity negatively, and clearing the infection produces a small significant rebound, but it is not known whether height and weight in children are impacted over the long term.

METHODS

We investigated 295 school-age children followed in 2 cohorts, treated (150) and untreated (145), from 2004 for 3.7 years with 1105 child-years of observation. Follow-up intervals were 3 months for anthropometry measurements and 6 months for H. pylori status ascertained by urea breath test. Height in centimeters and weight in kilograms were analyzed using growth models.

RESULTS

A multivariate mixed model that adjusted for age, sex, father's education, and number of siblings found no significant differences in height or weight at baseline by H. pylori status. The same model showed a significant impact of clearing H. pylori across time, with increasing significant differences in average height and weight as the follow-up progressed.

CONCLUSIONS

Children who were always negative or who cleared the infection grew significantly faster than those who stayed positive after adjusting for other covariates. This study suggests that school-age children's growth benefits from being treated for H. pylori infection.

Long-term effects of clearing Helicobacter pylori on growth in school-age children

BACKGROUND

A new Helicobacter pylori infection affects growth velocity negatively, and clearing the infection produces a small significant rebound, but it is not known whether height and weight in children are impacted over the long term.

METHODS

We investigated 295 school-age children followed in 2 cohorts, treated (150) and untreated (145), from 2004 for 3.7 years with 1105 child-years of observation. Follow-up intervals were 3 months for anthropometry measurements and 6 months for H. pylori status ascertained by urea breath test. Height in centimeters and weight in kilograms were analyzed using growth models.

RESULTS

A multivariate mixed model that adjusted for age, sex, father's education, and number of siblings found no significant differences in height or weight at baseline by H. pylori status. The same model showed a significant impact of clearing H. pylori across time, with increasing significant differences in average height and weight as the follow-up progressed.

CONCLUSIONS

Children who were always negative or who cleared the infection grew significantly faster than those who stayed positive after adjusting for other covariates. This study suggests that school-age children's growth benefits from being treated for H. pylori infection.

Helicobacter pylori eradication by sitafloxacin-lansoprazole combination and sitafloxacin pharmacokinetics in Mongolian gerbils and its in vitro activity and resistance development

A total of 293 strains of Helicobacter pylori, including strains resistant to levofloxacin, clarithromycin, metronidazole, or amoxicillin, were examined for in vitro susceptibility to 10 antimicrobial agents. Among these agents, sitafloxacin (a fluoroquinolone) showed the greatest activity (MIC(90), 0.06 μg/ml), with high bactericidal activity and synergy in sitafloxacin-lansoprazole (a proton pump inhibitor) combination. In a Mongolian gerbil model with a H. pylori ATCC 43504 challenge, marked eradication effects were observed at ≥1 mg/kg for sitafloxacin, ≥10 mg/kg for levofloxacin, and ≥10 mg/kg for lansoprazole, reflecting MIC levels for each agent (0.008, 0.25, and 2 μg/ml, respectively). The therapeutic rates were 83.3% for the sitafloxacin (0.3 mg/kg)-lansoprazole (2.5 mg/kg) combination and 0% for either sitafloxacin or lansoprazole alone. The maximum serum concentration (C(max)) of sitafloxacin was 0.080 ± 0.054 μg/ml at 30 min, when orally administered at 1 mg/kg. The simultaneous administration of lansoprazole resulted in no difference. In the resistance development assay, MICs of levofloxacin increased 64- to 256-fold with gyrA mutations (Ala88Pro and Asn87Lys), while MICs of sitafloxacin only up to 16-fold with the Asn87Lys mutation. The data suggest that sitafloxacin exhibited superior anti-H. pylori activity with low rates of resistance development in vitro and that, reflecting high in vitro activities, sitafloxacin-lansoprazole combination exhibited strong therapeutic effects in Mongolian gerbils with a C(max) of sitafloxacin that was 10-fold higher than the MIC value at a 1-mg/kg administration.

Effect of Helicobacter pylori infection on growth velocity of school-age Andean children

BACKGROUND

Helicobacter pylori infection affects about half of the world's population and is usually acquired in childhood. The infection has been associated with chronic gastritis, peptic ulcer, and stomach cancer in adulthood. Little is known, however, about its consequences on child health. We examined the effect of H. pylori infection on growth among school-age children in the Colombian Andes by comparing growth velocity in the presence and absence of H. pylori infection.

METHODS

Children who were 4-8 years old in 2004 were followed up in a community where infected children received anti-H. pylori treatment (n = 165) and a comparison community (n = 161) for a mean of 2.5 years. Anthropometry measurements were made every 3 months and H. pylori status ascertained by urea breath test every 6 months. Growth velocities (cm/month) were compared across person-time with and without infection, using mixed models for repeated measures.

RESULTS

In the untreated community, 83% were H. pylori-positive at baseline and 89% were -positive at study end. The corresponding prevalences were 74% and 46%, respectively, in the treated community. Growth velocity in the pretreatment interval was 0.44 (standard deviation [SD] = 0.13) cm/month. Models that adjusted for age, sex, and height estimated that H. pylori-positive children grew on average 0.022 cm/month (95% confidence interval = 0.008 to 0.035) slower than H. pylori-negative children, a result that was not appreciably altered by adjustment for socioenvironmental covariates.

CONCLUSIONS

This study suggests that chronic H. pylori infection is accompanied by slowed growth in school-age Andean children.

Effect of Helicobacter pylori infection on growth velocity of school-age Andean children

BACKGROUND

Helicobacter pylori infection affects about half of the world's population and is usually acquired in childhood. The infection has been associated with chronic gastritis, peptic ulcer, and stomach cancer in adulthood. Little is known, however, about its consequences on child health. We examined the effect of H. pylori infection on growth among school-age children in the Colombian Andes by comparing growth velocity in the presence and absence of H. pylori infection.

METHODS

Children who were 4-8 years old in 2004 were followed up in a community where infected children received anti-H. pylori treatment (n = 165) and a comparison community (n = 161) for a mean of 2.5 years. Anthropometry measurements were made every 3 months and H. pylori status ascertained by urea breath test every 6 months. Growth velocities (cm/month) were compared across person-time with and without infection, using mixed models for repeated measures.

RESULTS

In the untreated community, 83% were H. pylori-positive at baseline and 89% were -positive at study end. The corresponding prevalences were 74% and 46%, respectively, in the treated community. Growth velocity in the pretreatment interval was 0.44 (standard deviation [SD] = 0.13) cm/month. Models that adjusted for age, sex, and height estimated that H. pylori-positive children grew on average 0.022 cm/month (95% confidence interval = 0.008 to 0.035) slower than H. pylori-negative children, a result that was not appreciably altered by adjustment for socioenvironmental covariates.

CONCLUSIONS

This study suggests that chronic H. pylori infection is accompanied by slowed growth in school-age Andean children.

Helicobacter pylori infection in patients with chronic urticaria: correlation with pathologic findings in gastric biopsies

BACKGROUND

Chronic urticaria is a persistent urticaria lasting longer than 6 weeks, affecting 20% of the general population. Various infectious agents have been reported as causes of urticaria, including Helicobacter pylori, which is a common worldwide bacterial infection. Its role in inducing allergic conditions, such as chronic urticaria, has been suggested in some reports and ignored in others.

AIMS

To assess the prevalence of H. pylori infection in patients with chronic urticaria and to explore the possible etiopathogenetic link between them.

METHODS

Thirty-five patients suffering from chronic urticaria and 10 normal control individuals were subjected to upper endoscopic gastric biopsies to assess and semiquantify H. pylori infection and to address other pathologic abnormalities, using routine hematoxylin and eosin staining and Giemsa staining.

RESULTS

Forty percent of control subjects and 57% of patients were positive for H. pylori infection, but the difference did not reach statistically significant levels (P = 0.47). The severity of urticarial symptoms was greater in the H. pylori-positive than in the H. pylori-negative group (P = 0.019). Heavy bacterial colonization (P = 0.008) and intense gastric inflammation (P < 0.0001) were associated significantly with severe clinical manifestations. Eighty percent of the H. pylori-positive urticaria group experienced complete remission after receiving eradication therapy for H. pylori.

CONCLUSIONS

Helicobacter pylori may have a role in the exacerbation of urticarial symptoms, even though it is not involved directly in its etiology, and its eradication may lead to symptom improvement in a considerable number of infected urticaria patients. The severity of symptoms is dependent on the density of bacterial infection and the intensity of inflammatory infiltrate in the gastric biopsy.

Etiology of fibromyalgia: the possible role of infection and vaccination

Fibromyalgia syndrome (FMS), a condition characterized by widespread pain and diffuse tenderness, is considered a multifactorial disorder. FMS is now recognized as one of the "central" pain syndromes. Environmental and genetic factors play a role in the pathogenesis of FMS. Various triggers including trauma and stress as well as infections, may precipitate the development of FMS. Certain infections including hepatitis C virus, HIV and Lyme disease have been temporally associated with the development of FMS. There is some evidence for the possible role of vaccinations in triggering the development of FMS and related syndromes, however this association remains to be established.

Helicobacter pylori infection in Canadian and related Arctic Aboriginal populations

In 2006, the Canadian Helicobacter Study Group identified Aboriginal communities among Canadian population groups most at risk of Helicobacter pylori-associated disease. The objective of this systematic review was to summarize what is known about the H pylori-associated disease burden in Canadian and related Arctic Aboriginal populations to identify gaps in knowledge. Six health literature databases were systematically searched to identify reports on H pylori prevalence in Canadian population groups, or any topic related to H pylori in Canadian Aboriginals, Alaska Natives or Aboriginals of other Arctic regions. Identified reports were organized by subtopic and summarized in narrative form. Key data from studies of H pylori prevalence in defined populations were summarized in tabular form. A few Arctic Aboriginal communities were represented in the literature: two Canadian Inuit; one Canadian First Nation; two Greenland Inuit; one Russian Chutkotka Native; and several Alaska Native studies. These studies uniformly showed elevated H pylori prevalence; a few studies also showed elevated occurrence of H pylori-related diseases and high rates of treatment failure. Based on the evidence, it would be warranted for clinicians to relax the criteria for investigating H pylori and related diseases in patients from Arctic Aboriginal communities, and to pursue post-therapy confirmation of eradication. Additional community-based research is needed to develop public health policies for reducing H pylori-associated health risks in such communities.

[Does Helicobacter pylori infection play a role in extragastric diseases?]

Since the discovery of Helicobacter pylori (H. pylori), numerous studies have considered the possibility that it plays a role in different extragastric diseases. Most of these studies may be classified as epidemiological studies or investigations of H. pylori eradication, but there are also case reports and in vitro studies. This review reveals the limitations common to most of them. Idiopathic thrombocytopenic purpura is the disease for which the strongest association with H. pylori infection has been shown. Data are also accumulating about the role of H. pylori infection in idiopathic iron deficiency anemia and chronic idiopathic urticaria. Interesting results show that H. pylori infection affects atherosclerosis and is weakly associated with ischemic heart disease and stroke. Moreover, CagA-positive H. pylori strains may play a role in the natural history of atherosclerotic stroke. Recent studies suggest a link between H. pylori and Parkinson's disease. Preliminary data indicate that H. pylori infection impairs gastric ghrelin production and may influence nutritional status. The association between H. pylori infection and other extragastric diseases remains controversial. H. pylori infection may cause extragastric manifestations directly or indirectly, by various mechanisms including atrophic gastritis, the release of inflammatory mediators, molecular mimicry, and systemic immune response. Evidence suggests that anti-H. pylori therapy improves idiopathic thrombocytopenic purpura (significant increase of platelet count in half of the cases), iron-deficiency anemia, and chronic urticaria (30% remission rate), but the data from randomized controlled trials are insufficient to confirm these positive effects.

Helicobacter pylori: testing and treatment

Helicobacter pylori is an important pathogen worldwide. Accurate diagnosis and appropriate therapy is important in clinical practice. Invasive tests that accurately identify current infection include the biopsy urease test and histology. The best noninvasive tests for diagnosis include the urea breath test and stool antigen testing. Proton pump inhibitor therapy can lead to false-negative H. pylori test results, and treatment should be stopped for 1-2 weeks prior to testing if possible. In the setting of bleeding peptic ulcer disease, urea breath testing is recommended to rule out a false-negative biopsy test result if needed. The current recommendations for when to test for H. pylori vary around the world. Well-accepted indications include active and past ulcer disease, and gastric-mucosa associated lymphoid tissue lymphoma. There is no universal agreement regarding whether all patients with functional dyspepsia should be tested and treated, although this is an evidence-based recommendation. There is also evidence that H. pylori eradication prevents peptic ulcer disease in those starting NSAIDs long term. Primary treatment remains triple therapy with 10-14 days probably being superior to shorter courses of therapy. Quadruple therapy is recommended if standard triple therapy fails. Salvage therapies with levofloxacin, rifabutin or furazolidone have been identified. Novel approaches to treatment include sequential therapy and use of adjuvants.