New approaches to Helicobacter pylori infection in children

Helicobacter pylori antigens as immunomodulators of immune system

Helicobacter pylori (H. pylori) is one of the most prevalent human pathogens and the leading cause of chronic infection in almost half of the population in the world (~59%). The bacterium is a major leading cause of chronic gastritis, gastric and duodenal ulcers, and two type of malignancies, gastric adenocarcinoma and mucosa-associated lymphoid tissue (MALT) lymphoma. Despite the immune responses mounted by the host, the bacteria are not cleared from the body resulting in a chronic infection accompanied by a chronic inflammation. Herein, a review of the literature discussing H. pylori antigens modulating the immune responses is presented. The mechanisms that are involved in the modulation of innate immune response, include modulation of recognition by pattern recognition receptors (PRRs) such as modulation of recognition by toll like receptors (TLR)4 and TLR5, modulation of phagocytic function, and modulation of phagocytic killing mediated by reactive oxygen species (ROS) and nitric oxide (NO). On the other hands, H. pylori modulates acquired immune response by the induction of tolerogenic dendritic cells (DCs), modulation of apoptosis, induction of regulatory T cells, modulation of T helper (Th)1 response, and modulation of Th17 response.

Breastfeeding Is Associated with Lower Likelihood of Helicobacter Pylori Colonization in Babies, Based on a Prospective USA Maternal-Infant Cohort

BACKGROUND

Mother-to-child transmission of Helicobacter pylori (H. pylori) is the primary source of intrafamilial spread in early childhood in regions of high H. pylori prevalence. However, early-in-life H. pylori colonization and associated protective or risk factors have not been fully evaluated in lower prevalence regions, such as the USA.

AIMS

Therefore, from a well-characterized prospective US cohort, we selected women who provided fecal samples during pregnancy and had paired fecal samples from their babies up to 24 months postpartum. We evaluated maternal and baby factors associated with likelihood of H. pylori colonization in the babies. Fecal antigen testing was used to determine H. pylori status. We also evaluated the association between maternal breastmilk cytokines and H. pylori colonization in breastfed babies.

RESULTS

Among included mother-baby pairs (n = 66), H. pylori prevalence was 31.8% in mothers and 19.7% in their babies. Dominant breastfeeding (adjusted odds ratio [aOR] 0.17, 95% CI 0.03-0.98) and maternal IBD (aOR 0.05, 95% CI 0.01-0.27) were associated with significantly lower likelihood of H. pylori colonization among babies; no other clinical factors were associated with H. pylori colonization in the babies. Matrix metalloproteinase-10 (MMP-10) and tumor necrosis factor-related activation-induced cytokine expression were significantly higher in breastmilk of mothers with H. pylori positive vs negative babies.

CONCLUSIONS

Consistent with data from high H. pylori prevalence regions, our findings suggest dominant breastfeeding may protect against early H. pylori colonization. Downregulation of pro-inflammatory cytokines such as MMP-10 may be relevant in mediating this protection among breastfed babies, but more data are needed.

The influence of the dietary intake of vitamin C and vitamin E on the risk of gastric intestinal metaplasia in a cohort of Koreans

OBJECTIVES

Studies have suggested that the dietary intake of antioxidant vitamins, such as vitamin C and vitamin E, has a potential role in inhibiting gastric carcinogenesis. The present study investigated the effect of antioxidant vitamins on the incidence of gastric intestinal metaplasia (GIM).

METHODS

This study included 67,657 Koreans free of GIM who periodically underwent health check-ups. Dietary intake was assessed by a semiquantitative food frequency questionnaire based on the Korean National Health and Nutrition Examination Survey. Participants were categorized into 4 groups by quartiles of dietary vitamin C and vitamin E intake. The Cox proportional hazard assumption was used to determine the multivariable hazard ratio (HR) and 95% confidence interval (95% CI) for GIM.

RESULTS

The third and fourth quartiles of vitamin C intake had a lower risk of GIM than the first quartile (multivariable-adjusted HR, 0.95; 95% CI, 0.88 to 1.03 in the second quartile, HR, 0.88; 95% CI, 0.81 to 0.97 in the third quartile, and HR, 0.85; 95% CI, 0.76 to 0.95 in the fourth quartile). Vitamin E intake greater than the second quartile level was significantly associated with a lower risk of GIM than the first quartile (multivariable-adjusted HR, 0.90; 95% CI, 0.82 to 0.97 in the second quartile, HR, 0.90; 95% CI, 0.82 to 0.99 in the third quartile, and HR, 0.83; 95% CI, 0.74 to 0.94 in the fourth quartile). This association was observed only in the subgroup analysis for men.

CONCLUSIONS

Higher dietary intake of vitamin C and vitamin E was associated with a lower risk of GIM.

Helicobacter pylori evasion strategies of the host innate and adaptive immune responses to survive and develop gastrointestinal diseases

Helicobacter pylori (H. pylori) is a bacterial pathogen that resides in more than half of the human population and has co-evolved with humans for more than 58,000 years. This bacterium is orally transmitted during childhood and is a key cause of chronic gastritis, peptic ulcers and two malignant cancers including MALT (mucosa-associated lymphoid tissue) lymphoma and adenocarcinoma. Despite the strong innate and adaptive immune responses, H. pylori has a long-term survival in the gastric mucosa. In addition to the virulence factors, survival of H. pylori is strongly influenced by the ability of bacteria to escape, disrupt and manipulate the host immune system. This bacterium can escape from recognition by innate immune receptors via altering its surface molecules. Moreover, H. pylori subverts adaptive immune response by modulation of effector T cell. In this review, we discuss the immune-pathogenicity of H. pylori by focusing on its ability to manipulate the innate and acquired immune responses to increase its survival in the gastric mucosa, leading up to gastrointestinal disorders. We also highlight the mechanisms that resulted to the persistence of H. pylori in gastric mucosa.

Management of Helicobacter pylori infections

BACKGROUND

Infection with Helicobacter pylori is associated with severe digestive diseases including chronic gastritis, peptic ulcer disease, and gastric cancer. Successful eradication of this common gastric pathogen in individual patients is known to prevent the occurrence of peptic ulcer disease and gastric cancer.

DISCUSSION

With half of the world's population being infected with H, pylori and only few antibiotics result in an effective eradication, a successful antibiotic driven worldwide eradication program seems unlikely. In addition, H. pylori eradication is not always beneficial as it has been described that eradication can be associated with an increased frequency of other disorders such as pediatric asthma, inflammatory bowel diseases and Barrett's Esophagus. We have to accept that eradication of this infection is a two-edged sword that is both useful and harmful and we should therefore focus our H. pylori eradication policy toward selectively identify and destroy only the virulent strains.

CONCLUSION

In order to still be able to effectively treat H. pylori infections in the future we need an alternative diagnostic/treatment algorithm. This would involve a shift towards more precise and enhanced disease predicting diagnosis that tries to identify patients with chance of developing severe diseases such as gastric cancer, rather than the current regime that is geared towards find and destroy all H. pylori.

Prevalence and risk factors of atrophic gastritis and intestinal metaplasia: a nationwide multicenter prospective study in Korea

Background/Aims

Atrophic gastritis (AG) and intestinal metaplasia (IM) are premalignant gastric lesions. The aims of this study were to evaluate the prevalence of endoscopic AG and IM and to document the risk factors for these lesions.

Methods

In total, 4,023 subjects were enrolled at eight hospitals in Korea. AG and IM were diagnosed by endoscopy. Helicobacter pylori immunoglobulin G antibodies were measured.

Results

The prevalences of endoscopic AG and IM were 40.7% and 12.5%. In a multivariate analysis, the risk factors for AG were age groups of 40 to 59 years and >60 years, male sex, positive H. pylori serology, IM, and education below the college level (odds ratio [OR], 2.55, 5.00, 1.38, 1.41, 4.29, and 1.35, respectively). The risk factors for IM were age groups of 40 to 59 years and >60 years, male sex, positive H. pylori serology, AG, having relatives with gastric cancer, education below the college level and consumption of dairy products (OR, 3.16, 3.25, 1.88, 2.17, 3.68, 1.48, 1.47, and 1.40, respectively).

Conclusions

A nationwide survey regarding the prevalence of endoscopic AG and IM and their risk factors in Korea supports the hypothesis that endoscopic diagnosis of these premalignant lesions could be helpful to describe a group at high risk for gastric cancer.

The role of Helicobacter pylori infection in gastro-oesophageal reflux in Iranian children

BACKGROUND

The relationship between Helicobacter pylori and gastro-oesophageal reflux disease (GORD) in children is controversial.

AIM

To determine the role of H. pylori infection and GORD in children living in a region which is endemic for H. pylori infection.

METHODS

A cross-sectional study was undertaken in 263 children aged 3-18 years, all of whom had symptoms of GORD and underwent upper gastro-intestinal endoscopy. H. pylori status was determined by conventional rapid urease test and Giemsa staining of antral and cardiac biopsies. Biopsies of the oesophagus and gastric mucosa were obtained from the lower oesophagus, the antrum and cardia according to standard protocol.

RESULTS

Of the 263 patients, 81 (31·5%) had GORD and 162 (61·5%) had gastritis. There were 59 H. pylori-infected patients (22·4%) and 204 were uninfected. H. pylori infection was detected in 52 (88·1%) of the antral and 10 (1·9%) of the cardiac biopsies. Three (5·1%) of the biopsies revealed infection of both antrum and cardia and in seven (11·8%) only the cardia was infected. The prevalence of H. pylori infection among patients with GORD (13/83, 15%) was significantly lower than in those without GORD (46/180, 26%) (OR 0·54, CI 0·27-0·93, p<0·05). The prevalence of H. pylori infection among those with gastritis (48/162, 30%) was significantly higher than in those without gastritis (11/101, 10·8%) (OR 3·44, CI 1·69-7·015, p<0·001).

CONCLUSION

H. pylori infection might protect against GORD.

Helicobacter pylori infection in children

Helicobacter pylori infection is a common problem in pediatric practice, and its acquisition is related with poor socioeconomic conditions. Although the organism is thought to be responsible for many diseases, only a handful of them have a direct causal relationship. At present, only a small number of children with well-defined clinical syndromes are benefited from testing and treatment. The treatment should include at least two antibiotics with a proton pump inhibitor.

Aetiology of recurrent abdominal pain in a cohort of Sri Lankan children

AIMS

Recurrent abdominal pain (RAP) has a multifactorial aetiology with many affected children having no evidence of organic pathology. This study assessed the functional and organic causes for RAP in a cohort of Sri Lankan children.

METHODS

Fifty-five Sri Lankan children (45.5% males, aged 5-15 years) having RAP were screened for organic diseases. RAP was defined using Apley criteria. Children without clinical or laboratory evidence of organic diseases were classified into functional gastrointestinal diseases (FGD) using Rome II and III criteria. Thirty-nine patients with functional RAP and 20 healthy children (50% males, age 5-15 years) from same area were tested for Helicobacter pylori using a stool antigen test.

RESULTS

Thirteen (23.6%) children had organic RAP. According to Rome II, 33 (60%), and according to Rome III, 39 (71%) (functional abdominal pain 19, irritable bowel syndrome nine, functional dyspepsia nine, abdominal migraine one, aerophagia one) children had FGD. Two (5.1%) patients and one (5%) control tested were positive for Helicobacter pylori (P > 0.05). Except for constipation, pain characteristics and associated symptoms were not significantly different between organic and functional RAP.

CONCLUSIONS

Organic pathology accounted for symptoms in less than a quarter of Sri Lankan children with RAP. The majority had functional bowel diseases, of which the commonest was functional abdominal pain. Rome III criteria were more effective than Rome II criteria in identifying FGD. Helicobacter pylori infection did not appear to be associated with RAP.

Investigation of Helicobacter pylori infection in beta-thalassaemia major patients with recurrent abdominal pain

BACKGROUND

Recurrent abdominal pain (RAP) affects many children, especially those affected by beta-thalassaemia major. The role of Helicobacter pylori is still unclear in children with RAP.

OBJECTIVES

The aim of the present study was the comparison of beta-thalassaemia major patients and normal controls with RAP in H. pylori infection. The factors influencing H. pylori prevalence were also investigated.

METHODS

A series of 50 beta-thalassaemia major cases (30 female, 20 male; aged 6-25 years) and 50 age-matched and sex-matched controls, both presenting with RAP, were recruited during a period of 18 months. The study participants were obtained through a multistage random sampling method among those that met Apley's criteria. All the patients and controls had undergone diagnostic oesophagogastroduodenoscopy with biopsy. H. pylori infection was confirmed by two histopathological examinations on an endoscopy sample and a rapid urease test.

RESULTS

H. pylori infection in thalassaemic patients was more common than in controls [34/50 (68%) versus 30/50 (60%)], but this higher frequency was not statistically significant. A clear relationship was found between the prevalence of H. pylori and age, duration of transfusion/chelation programmes, pain duration and splenectomy. In contrast, H. pylori did not correlate with abdominal pain characteristics, blood group, serum ferritin level and pathology of the upper gastrointestinal tract. The most frequent endoscopy abnormality was gastritis (72%). Nausea and heartburn were the leading associated symptoms.

CONCLUSION

The high prevalence of H. pylori infection suggests that H. pylori should be remembered as a probable cause of RAP in beta-thalassaemia major patients.

Seroprevalence of Helicobacter pylori among children in Sana'a, Yemen

BACKGROUND

Helicobacter pylori infection is primarily acquired in early childhood. Its transmission routes are debated. The aims of this study were to determine the seroprevalence of anti-H. pylori immunoglobulin G (IgG) in Yemeni children under 10 years of age, the potential risk factors for contracting H. pylori infection and co-infection of H. pylori with intestinal parasites.

METHODS

Enzyme-labeled immunosorbent assay was used to determine the H. pylori prevalence rate among 572 healthy volunteers aged less than 10 years. Formalin ether concentration methods were used to test the prevalence of intestinal parasites (intestinal roundworms and tapeworms). In addition, we interviewed participants regarding potential risk factors for contracting H. pylori infection.

RESULTS

The seroprevalence of H. pylori antibodies was 9%. The prevalence according to age varied from 0% in children under 2 years to 12.5% in age group 9-10 years. There was a correlation between the amounts of positive antibodies and increasing age. The prevalence rate of H. pylori antibodies was also significantly associated with the practice of drinking water from reused plastic jerry cans, with poor mouth hygiene and with co-infection by intestinal parasites.

CONCLUSION

The prevalence of H. pylori antibodies in Yemen among children under 10 years of age is higher than that reported from other regions for the same age groups. Yemen shares some but not all potential risk factors for H. pylori infection with countries in which similar socioeconomic conditions are found. A possible way of eliminating H. pylori from the population would be via public health measures, i.e. preventing the reuse of plastic jerry cans, and improving sanitation and the standard of living.

Helicobacter pylori infection: detection, investigation, and management

Helicobacter pylori infection causes gastritis and peptic ulcers and is associated with the development of gastric cancer. Approximately 50% of the world population is infected with H pylori , with the highest prevalence rates in developing countries. In the vast majority of individuals, infection is acquired during childhood with those of low socioeconomic means and having infected family members being at highest risk for early childhood acquisition. Definitive routes of transmission of the infection are unclear, with evidence suggesting oral-oral, gastric-oral, and fecal-oral routes. If untreated, H pylori infection is lifelong. Although clinical disease typically occurs decades after initial infection acquisition, children infected with H pylori may have gastritis, ulcers, mucosal-associated lymphoid type lymphoma, and, rarely, gastric atrophy with/without intestinal metaplasia (ie, both precursor lesions for gastric cancer). Controversy persists regarding testing for and treating H pylori , if found, in the large number of children who present with recurrent abdominal pain. Because young children (ie, younger than 5 years of age) who are treated and cured of their H pylori infection may be at risk for reinfection, the current recommendations do not recommend treatment unless an ulcer or gastric atrophy is present. However, despite the lack of clinical evidence, the trend is to more aggressively screen children for the presence of H pylori and to treat those children who are found to have the infection. H pylori infection can be eradicated by antimicrobial therapy plus a proton pump inhibitor, but no treatment regimen is 100% effective. Multiple drugs, frequent dosing, and length of treatment often contribute to poor patient compliance, and antibiotic eradication therapy is associated with increasing drug resistance.

Helicobacter pylori infection in pediatrics

The proposed route of Helicobacter pylori transmission appears to be fecal-oral, oral-oral and gastro-oral, yet, a number of studies challenged these hypotheses in 2003. The use of the stool antigen test and[13]-C urea breath testing were the tests of choice for diagnosis and 'test for cure' of H. pylori in Europe in 2003 but have not yet become accepted standard of care in North America. Pediatric H. pylori consensus guidelines are not yet revised; upper endoscopy and biopsy remain the gold standard for diagnosis of pediatric H. pylori infection. In addition to stronger evidence supporting the role of host influences of H. pylori-associated gastric cancer risk, compelling evidence was provided for the role of H. pylori in iron deficiency anemia of childhood. Antibiotic resistance remains a problem in conferring treatment failure and 2003 studies indicate that macrolide resistance is higher in children than in adults. Treatment with proton pump inhibitor-based triple therapy for 10-14 days remains the mainstay for eradication of H. pylori in childhood. Finally, multinational studies are needed to develop screening guidelines for childhood infection to avoid long-term severe gastroduodenal disease sequelae.

Knowledge, attitudes, and practice styles of North American pediatric gastroenterologists: Helicobacter pylori infection

OBJECTIVE

Most Helicobacter pylori infections are acquired during childhood. The North American Society for Pediatric Gastroenterology, Hepatology and Nutrition (NASPGHAN) recently published practice guidelines for managing pediatric H. pylori infection. Before this publication, the authors conducted a survey to assess pediatric gastroenterologists' knowledge and practices regarding H. pylori.

METHODS

One hundred nine of 514 NASPGHAN members completed an Internet-based questionnaire on H. pylori infection.

RESULTS

Eighty-two percent of respondents performed outpatient testing for H. pylori. Of these, only 31% restricted testing to children aged >5 years. Most recommended testing for H. pylori in guideline-recommended conditions; some would not treat infected patients. Ninety-seven percent would test for H. pylori in a child with new duodenal ulcer (DU), 79% in a child with a history of DU, and 91% in a child with new gastric ulcer. However, only 86%, 60%, and 91%, respectively, would treat H. pylori infection in those conditions. A proton pump inhibitor (PPI)-based triple regimen was the first-choice therapy for 78% of respondents. Correct estimates of rates of resistance to amoxicillin, clarithromycin, metronidazole, and tetracycline were 10%, 17%, 43%, and 12%, respectively. Eighty-six percent believed there was insufficient research on H. pylori in children.

CONCLUSIONS

North American pediatric gastroenterologists seem well informed about H. pylori infection in children despite the lack of published guidelines at the time of survey. Knowledge about antibiotic resistance rates was deficient. Most offered some outpatient testing for H. pylori and would test children with ulcer disease. However, some would not treat patients based on a positive result.

Abdominal migraine: evidence for existence and treatment options

There is evidence to suggest that, in children, episodic abdominal pain occurring in the absence of headache may be a migrainous phenomenon. There are four separate strands of evidence for this: the common co-existence of abdominal pain and migraine headaches; the similarity between children with episodic abdominal pain and children with migraine headaches, with respect to social and demographic factors, precipitating and relieving factors, and accompanying gastrointestinal, neurological and vasomotor features; the effectiveness of nonanalgesic migraine therapy (such as pizotifen, propanolol, cyproheptadine and the triptans) in abdominal migraine; and the finding of similar neurophysiological features in both migraine headache and abdominal migraine. Abdominal migraine is rare, but not unknown, in adults. Many families are content with a diagnosis and reassurance that the episodes, though distressing, are not the result of serious pathology. Some patients respond to simple dietary and other prophylactic measures. There is scant evidence on which to base recommendations for the drug management of abdominal migraine. What little literature exists suggests that the antimigraine drugs pizotifen, propanolol and cyproheptadine are effective prophylactics. Nasal sumatriptan (although not licensed for pediatric use) may be effective in relieving abdominal migraine attacks.

Helicobacter pylori infection in children

A number of scientific breakthroughs since H pylori first became recognized as a human pathogen have increased our understanding of the pathogenesis of gastroduodenal disease. In particular, advances in molecular bacteriology and the complete sequencing of the H pylori genome in 1999, and soon thereafter the human genome, provide tools allowing better delineation of the pathogenesis of disease. These molecular tools for both bacteria and host should now be applied to multicenter pediatric studies that evaluate disease outcome. More recent developments indicate that a better understanding of the microbial-host interaction is critical to furthering knowledge with respect to H pylori-induced diseases. Studies are needed to evaluate either DNA-based or more traditional protein-based vaccines, to evaluate more specific antimicrobials that confer minimal resistance, and to evaluate probiotics for the management of H pylori infection. Multicenter multinational studies of H pylori infection in the pediatric population, which include specific, randomized controlled eradication trials, are essential to extend current knowledge and develop better predictors of disease outcome.