Cytokine expression in pediatric Helicobacter pylori infection

Correlation Analysis of Helicobacter pylori Infection and Digestive Tract Symptoms in Children and Related Factors of Infection

BACKGROUND

To analyze the correlation between Helicobacter pylori infection and digestive tract symptoms in children and other related factors, and to explore the risk factors of H. pylori infection in children and the expression of inflammatory factors in H. pylori-positive and H. pylori-negative children.

METHODS

Overall, 234 children with H. pylori test in Xuzhou Children's Hospital, Xuzhou Medical University (Xuzhou, China) were enrolled. Among them, 73 children were H. pylori-positive and 161 were H. pylori-negative. The expression levels of cytokines interleukin-8 (IL-8), interleukin-18 (IL-18) and interferon-γ (IFN-γ) in H. pylori-positive and H. pylori-negative children were determined by ELISA. The correlation between H. pylori-positive and general data, digestive tract symptoms, other clinical symptoms, living habits, eating habits, family history and other related factors was statistically analyzed. Multivariate Logistic regression analysis was used to analyze the independent risk factors of H. pylori infection in children.

RESULTS

Family monthly income, inattentive eating, sharing toothbrushes and cups, gnawing fingers, eating fried food, drinking raw water, eating smoked and pickled food, father suffering from gastropathy and mother suffering from gastropathy were independent risk factors for H. pylori infection in children. The most common digestive tract symptoms of children with H. pylori infection were abdominal pain, accompanied by one or more clinical symptoms. The expression levels of IL-8, IL-18 and IFN-γ in H. pylori-positive children were significantly higher than those in H. pylori-negative children.

CONCLUSION

Prevention of H. pylori infection in children is helpful for healthy growth of children, and cytokines IL-8, IL-18, IFN-γ have the potential to be used as biomarkers for diagnosis of H. pylori-positive children.

Changes in the severity of gastric mucosal inflammation associated with Helicobacter pylori in humans coinfected with intestinal helminths

BACKGROUND

Though a few studies in animal models suggest that intestinal helminths (IH) favorably affect evolution of gastritis associated with Helicobacter pylori (H. pylori) the studies supporting this concept in humans are only a few and are based on serological data.

METHODS

To evaluate the possible influence of IH on the human gastric mucosa, three groups of Venezuelan adults with gastropathy (endoscopically diagnosed) were studied: H. pylori-/IH- (n = 17), H. pylori+/IH- (n = 18), and H. pylori+/IH+ (n = 11). Histological analysis (hematoxylin-eosin) and immunohistochemical staining (peroxidase) for cytokines interleukin-1beta (IL-1β), tumor necrosis factor alpha (TNF-α), gamma interferon (IFN-γ), and interleukin 4 (IL-4) were undertaken in gastric antral biopsies.

RESULTS

Expression of the four cytokines was detected in all individuals in varying degrees, but proinflammatory cytokines were expressed in a higher degree in the H. pylori+/IH- group, mainly IL-1β (Th1-dominant immune response), associated with a higher degree of both histological inflammation and gastric cancer risk index (GCRI), as compared to the H. pylori-/IH- group. In contrast, an increased expression of IL-4 and a reduced expression of proinflammatory cytokines (Th2-dominant response), plus the tendency to a lower degree of mononuclear infiltration, mucosal atrophy in gastric corpus, and GCRI, were evidenced in the coinfected group.

CONCLUSIONS

The findings of the present study is perhaps the first histological evidence of a possible modulatory effect of IH on the gastric mucosal inflammatory response due to H. pylori infection in humans.

Helicobacter pylori vacA and cagA genotype diversity and interferon gamma expression in patients with chronic gastritis and patients with gastric cancer

BACKGROUND

Helicobacter pylori (H. pylori) is the main risk factor for the development of chronic gastritis, gastric ulcer, and gastric cancer. In H. pylori-infected individuals, the clinical result is dependent on various factors, among which are bacterial components, the immune response, and environmental influence.

AIMS

To compare IFN-γ expression with the H. pylori vacA and cagA genotypes in patients with chronic gastritis and patients with gastric cancer.

METHODS

Ninety-five patients diagnosed with chronic gastritis and 20 with gastric cancer were included in the study. Three gastric biopsies were taken; one was used for the molecular detection and genotyping of H. pylori; another was fixed in absolute alcohol and histologic sections were made for determining IFN-γ expression through immunohistochemistry.

RESULTS

No differences were found in the cells that expressed IFN-γ between the patients with chronic gastritis (median percentage of positive cells: 82.6% in patients without H. pylori and 82% in infected persons) and those with gastric cancer (70.5% in H. pylori-negative patients and 78.5% in infected persons). IFN-γ expression was 69% in chronic gastritis patients infected with H. pylori vacAs2m2/cagA⁻ it was 86.5% in patients infected with H. pylori vacAs1m2/cagA⁻, 86.5% in vacAs1m1/cagA⁻, and 82% in vacAs1m1/cagA⁺. Similar data were found in the patients with gastric cancer.

CONCLUSIONS

IFN-γ expression varied depending on the H. pylori vacA and cagA genotype, but not in accordance with the presence of chronic gastritis or gastric cancer.

Helicobacter pylori and T Helper Cells: Mechanisms of Immune Escape and Tolerance

Helicobacter pylori colonizes the gastric mucosa of at least half of the human population, causing a worldwide infection that appears in early childhood and if not treated, it can persist for life. The presence of symptoms and their severity depend on bacterial components, host susceptibility, and environmental factors, which allow H. pylori to switch between commensalism and pathogenicity. H. pylori-driven interactions with the host immune system underlie the persistence of the infection in humans, since the bacterium is able to interfere with the activity of innate and adaptive immune cells, reducing the inflammatory response in its favour. Gastritis due to H. pylori results from a complex interaction between several T cell subsets. In particular, H. pylori is known to induce a T helper (Th)1/Th17 cell response-driven gastritis, whose impaired modulation caused by the bacterium is thought to sustain the ongoing inflammatory condition and the unsuccessful clearing of the infection. In this review we discuss the current findings underlying the mechanisms implemented by H. pylori to alter the T helper lymphocyte proliferation, thus facilitating the development of chronic infections and allowing the survival of the bacterium in the human host.

Helicobacter pylori and T Helper Cells: Mechanisms of Immune Escape and Tolerance

Helicobacter pylori colonizes the gastric mucosa of at least half of the human population, causing a worldwide infection that appears in early childhood and if not treated, it can persist for life. The presence of symptoms and their severity depend on bacterial components, host susceptibility, and environmental factors, which allow H. pylori to switch between commensalism and pathogenicity. H. pylori-driven interactions with the host immune system underlie the persistence of the infection in humans, since the bacterium is able to interfere with the activity of innate and adaptive immune cells, reducing the inflammatory response in its favour. Gastritis due to H. pylori results from a complex interaction between several T cell subsets. In particular, H. pylori is known to induce a T helper (Th)1/Th17 cell response-driven gastritis, whose impaired modulation caused by the bacterium is thought to sustain the ongoing inflammatory condition and the unsuccessful clearing of the infection. In this review we discuss the current findings underlying the mechanisms implemented by H. pylori to alter the T helper lymphocyte proliferation, thus facilitating the development of chronic infections and allowing the survival of the bacterium in the human host.

The Efficacy of Saccharomyces boulardii CNCM I-745 in Addition to Standard Helicobacter pylori Eradication Treatment in Children

PURPOSE

This study aims to investigate Saccharomyces boulardii CNCM I-745 during Helicobacter pylori eradication in children.

METHODS

One hundred ninety-four H. pylori positive children were randomized in two groups. Therapy (omeprazole+clarithromycin+amoxicillin or omeprazole+clarithromycin+metronidazole in case of penicillin allergy) was given to both groups during two weeks. In the treatment group (n: 102) S. boulardii was added to the triple therapy, while the control group (n: 92) only received triple therapy. The incidence, onset, duration and severity of diarrhea and compliance to the eradication treatment were compared. A (13)C urea breath test was done 4 weeks after the end of eradication therapy in two groups of 21 patients aged 12 years and older to test the H. pylori eradication rate.

RESULTS

In the treatment group, diarrhea occurred in 12 cases (11.76%), starting after 6.25±1.24 days, lasting 3.17±1.08 days, and compliance to eradication treatment was 100%. In the control group, diarrhea occurred in 26 cases (28.26%), starting after 4.05±1.11 days, lasting 4.02±0.87 days, and in six cases eradication treatment was stopped prematurely (p<0.05). The (13)C urea breath test showed successful H. pylori eradication in 71.4% of the patients in the treatment and in 61.9 % in the control group (not significant).

CONCLUSION

S. boulardii has a beneficial effect on the prevention and treatment of diarrhea during H. pylori eradication in children. Although S. boulardii did only slightly increase H. pylori eradication rate, compliance to eradication treatment was improved.

Therapeutic efficacy of the multi-epitope vaccine CTB-UE against Helicobacter pylori infection in a Mongolian gerbil model and its microRNA-155-associated immuno-protective mechanism

Vaccination is an effective means of preventing infectious diseases, including those caused by Helicobacter pylori. In this study, we constructed a novel multi-epitope vaccine, CTB-UE, composed of the cholera toxin B subunit and tandem copies of the B and Th cell epitopes from the H. pylori urease A and B subunits. We evaluated the therapeutic efficacy of the multi-epitope vaccine CTB-UE against H. pylori infection in a Mongolian gerbil model and studied its immuno-protective mechanisms. The experimental results indicated that urease activity, H. pylori colonisation density, the levels of IL-8 and TNF-α in the serum, and the levels of COX-2 and NAP in gastric tissue were significantly lower and the IgG level in the serum and the IFN-γ level in spleen lymphocytes were significantly higher in the vaccinated group compared with the model control group; additionally, gastric mucosal inflammation was notably alleviated following vaccination. The results showed that CTB-UE had a good therapeutic effect on H. pylori infection. The immuno-protective mechanism was closely related to the immune response mediated by microRNA-155, the expression of which was strongly up-regulated after CTB-UE administration. The expression levels of the microRNA-155 target proteins IFN-γRα, AID, and PU.1 were significantly down-regulated; these results indicated that CTB-UE induced an immune response biased towards Th1 cells by up-regulating microRNA-155 to inhibit IFN-γRα expression and induced a humoral immune response towards B cells by up-regulating microRNA-155 to inhibit PU.1 and AID expression. These results demonstrate that the multi-epitope vaccine CTB-UE may be a promising therapeutic vaccine against H. pylori infection and is a new therapeutic tool for human use.

Characterization and functional properties of gastric tissue-resident memory T cells from children, adults, and the elderly

T cells are the main orchestrators of protective immunity in the stomach; however, limited information on the presence and function of the gastric T subsets is available mainly due to the difficulty in recovering high numbers of viable cells from human gastric biopsies. To overcome this shortcoming we optimized a cell isolation method that yielded high numbers of viable lamina propria mononuclear cells (LPMC) from gastric biopsies. Classic memory T subsets were identified in gastric LPMC and compared to peripheral blood mononuclear cells (PBMC) obtained from children, adults, and the elderly using an optimized 14 color flow cytometry panel. A dominant effector memory T (T_EM) phenotype was observed in gastric LPMC CD4⁺ and CD8⁺ T cells in all age groups. We then evaluated whether these cells represented a population of gastric tissue-resident memory T (T_RM) cells by assessing expression of CD103 and CD69. The vast majority of gastric LPMC CD8⁺ T cells either co-expressed CD103/CD69 (>70%) or expressed CD103 alone (~20%). Gastric LPMC CD4⁺ T cells also either co-expressed CD103/CD69 (>35%) or expressed at least one of these markers. Thus, gastric LPMC CD8⁺ and CD4⁺ T cells had the characteristics of T_RM cells. Gastric CD8⁺ and CD4⁺ T_RM cells produced multiple cytokines (IFN-γ, IL-2, TNF-α, IL-17A, MIP-1β) and up-regulated CD107a upon stimulation. However, marked differences were observed in their cytokine and multi-cytokine profiles when compared to their PBMC T_EM counterparts. Furthermore, gastric CD8⁺ T_RM and CD4⁺ T_RM cells demonstrated differences in the frequency, susceptibility to activation, and cytokine/multi-cytokine production profiles among the age groups. Most notably, children’s gastric T_RM cells responded differently to stimuli than gastric T_RM cells from adults or the elderly. In conclusion, we demonstrate the presence of gastric T_RM, which exhibit diverse functional characteristics in children, adults, and the elderly.

NF-κB activation and severity of gastritis in Helicobacter pylori-infected children and adults

BACKGROUND

In contrast to adults, Helicobacter pylori gastritis in children is reported as milder and ulcer disease as uncommon, but unequivocal data are lacking.

OBJECTIVES

To compare the frequency of gastro-duodenal ulcers in children and adults as well as the proportion of Helicobacter pylori infection in these patients and to study the effect of chronological age on NF-κB activation and on severity of gastritis.

DESIGN

Patients referred in one pediatric and one adult facility for upper GI endoscopy were included. Gastric biopsies were obtained in consecutive Helicobacter pylori-infected patients and age-matched negative controls for immunohistochemistry and electrophoresis mobility shift assay. Three age groups were defined: younger than 8 years, 8-17 years, and adults.

RESULTS

Peptic ulcer disease was less frequent in children and less frequently associated with Helicobacter pylori infection. When comparing infected subjects to controls, densities of neutrophils and CD20 cells in the lamina propria increased in all age groups, CD3 cells increasing only in patients older than 8 years and CD8 cells only in adults. NF-κB-p65-positive cells were also increased only in infected adults as well as NF-κB-binding activity. A positive correlation was found between age and densities of neutrophils and CD3, but not of CD8 or CD20 cells.

CONCLUSION

Peptic ulcer disease was less frequent in children and less frequently caused by Helicobacter pylori infection. The different clinical outcome of the infection in children can be the consequence of the lower mucosal immune response.

New immunological investigations on Helicobacter pylori-induced gastric ulcer in patients

Although Helicobacter pylori (Hp) plays an important role in the pathogenesis of chronic gastritis and gastric ulcer, little is known about the probable mechanisms of these types of gastrointestinal damage. To determine the precise mechanisms involved in ulcer formation, immune responses in patients with gastric ulcer (GUP) caused by Hp infection (Hp(+)) were compared with those of other gastritis patients (GP). The sensitivity and proliferation of peripheral blood mononuclear cells (PBMNCs) obtained from patients were evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay against exposure with complex Hp crude antigen (HPCA) and mitogen (phytohemagglutinin, PHA). Production of inflammatory cytokines, including interleukin (IL)-1β and IL-8, in serum and supernatants of PBMNCs were then measured by ELISA. It was found that, after stimulation with PHA, both IL-8 and IL-1β concentrations in sera and supernatants as well as proliferation and sensitivity were statistically greater in GUP Hp(+) than GP Hp(-) . Furthermore, HPCA inhibited the proliferation of PBMNCs dose-dependently; however, it stimulated IL-8 and IL-1β production in supernatants of mononuclear cells. Therefore, the up-regulated concentrations of IL-8 and IL-1β may have been caused by increase in the size of mononuclear cell subpopulations or in their cytokine secretory activity, indicating the greatest cell responsiveness in GUP Hp(+) patients. These results suggest that tissue damage and ulcers occur in patients who produce more IL-8 and IL-1β than patients who do not develop ulcers; the former consequently have more activated immune cells at the site of infection. Therefore, both host responses and Hp virulence factors may be involved in the development of gastric ulcers.

Toll-like receptors and cytokines are upregulated during Helicobacter pylori infection in children

BACKGROUND AND AIM

Helicobacter pylori infection is mainly acquired during childhood, and establishes a chronic infection that may lead to peptic ulcer or gastric cancer during adulthood. Toll-like receptors (TLRs) are expressed by distinct cell types throughout the gastrointestinal tract, and play an important role in regulation of the innate immune response. Few works have addressed TLRs expression in gastric epithelia of adults, and scarce studies have done it in children. The aim of this work was to analyze the expression of TLR2, TLR4, TLR5, TLR9, and IL-8, IL-10 and TNF-α in the gastric mucosa of children with and without H. pylori infection.

METHODS

Gastric biopsies were collected by endoscopy from 50 children with recurrent abdominal pain, 25 with H. pylori infection and 25 without infection. In the gastric biopsies the expression of TLRs and cytokines was studied by immunohistochemistry, and the degree of mucosal inflammation was determined using the Sydney system.

RESULTS

We found that H. pylori infection was associated with a significant increased expression of TLRs 2, 4, 5 and 9, although expression varied between surface epithelia and glands. Epithelial cells expressing IL-8, IL-10 and TNF-α were increased in gastric mucosa of children with H. pylori infection.

CONCLUSION

This study shows the gastric epithelia of children respond to H. pylori infection by increasing the expression of TLR2, TLR4, TLR5, TLR9 and the cytokines IL-8, IL-10 and TNF-α.

Probiotics-containing yogurts suppress Helicobacter pylori load and modify immune response and intestinal microbiota in the Helicobacter pylori-infected children

BACKGROUND

 The benefits of probiotics to the pediatric Helicobacter pylori infection remain uncertain. We tested whether the H. pylori-infected children have an altered gut microflora, and whether probiotics-containing yogurt can restore such change and improve their H. pylori-related immune cascades.

METHODS

We prospectively included 38 children with H. pylori infection confirmed by a positive ¹³C-urea breath test (UBT) and 38 age- and sex-matched noninfected controls. All of them have provided the serum and stool samples before and after 4-week ingestion of probiotics-containing yogurt. The serum samples were tested for the TNF-α, IL-10, IL-6, immunoglobulin (Ig) A, G, E, pepsinogens I and II levels. The stool samples were tested for the colony counts of Bifidobacterium spp. and Escherichia coli. The follow-up UBT indirectly assessed the H. pylori loads after yogurt usage.

RESULTS

 The H. pylori-infected children had lower fecal Bifidobacterium spp. count (p = .009), Bifidobacterium spp./E. coli ratio (p = .04), serum IgA titer (p = .04), and pepsinogens I/II ratio (p < .001) than in controls. In the H. pylori-infected children, 4-week yogurt ingestion reduced the IL-6 level (p < .01) and H. pylori loads (p = .046), but elevated the serum IgA and pepsinogen II levels (p < .001). Moreover, yogurt ingestion can improve the childhood fecal Bifidobacterium spp./E. coli ratio (p = .03).

CONCLUSIONS

 The H. pylori-infected children have a lower Bifidobacterium microflora in gut. The probiotics-containing yogurt can offer benefits to restore Bifidobacterium spp./E. coli ratio in children and suppress the H. pylori load with increment of serum IgA but with reduction in IL-6 in H. pylori-infected children.

FOXP3+ regulatory T cells in children with helicobacter pylori infection

Despite an intensive pro-inflammatory response, the immune system is unable to clear the organism in Helicobacter pylori gastritis. Regulatory T (Treg) cells, which suppress the immune response of antigen-specific T cells, have recently been demonstrated to play a key role in chronic inflammation by immunologic tolerance. The purpose of our study was to investigate the histopathology, FOXP3+CD4+CD25(high)Treg (FOXP3+Treg) cell expression, and immune responses in children with H. pylori infection. Twenty-four H. pylori -positive and 24 H. pylori -negative children who underwent esophagogastroduodenoscopy for dyspeptic symptoms were included. Histopathologic grading according to the updated Sydney classification and immunohistochemical stains for FOXP3, transforming growth factor-β1 (TGF-β1), and CD4 were performed. Histopathologic bacterial density score, gastritis activity score, and chronic inflammation score were higher in the H. pylori -positive group than in the negative group (P < 0.01). The number of FOXP3+Treg cells and CD4+T cells and the grade of TGF-β1 expression were significantly increased in the H. pylori -positive group compared to the negative group (P < 0.01). The number of FOXP3+Treg cells correlated positively with the grade of TGF-β1 expression regardless of H. pylori status (P < 0.05). The number of FOXP3+Treg cells and the grade of TGF-β1 expression correlated positively with H. pylori density, gastritis activity score, and chronic inflammation score regardless of H. pylori status (P < 0.01). These findings indicate that FOXP3+Treg cells could play a role in persistent H. pylori infection.

Pediatric Helicobacter pylori infection and circulating T-lymphocyte activation and differentiation

BACKGROUND

In this study, H. pylori-infected and noninfected children with gastritis were compared to a control group with respect to circulating CD4(+) and CD8(+) T lymphocytes expressing activation and differentiation markers. Additionally, the lymphocyte phenotypes of children with gastritis were correlated with the gastric inflammation scores.

MATERIALS AND METHODS

H. pylori infection status was assessed based on [¹³C]urea breath test, rapid urease test, and histology. Analysis of the lymphocyte surface molecule expression was carried out by triple-color flow cytometry.

RESULTS

The group of H. pylori-infected children showed an elevated proportion of peripheral B cells with CD19(low) , along with a twofold increase in the percentage of memory (CD45RO(+)) CD4(+) and CD8(+) T-cell subsets (p < .05). Moreover, a positive correlation between the age and the percentage of these subsets was seen (r = .38, p = .04 and r = .56, p < .01, respectively). Children with gastritis but without infection had a slightly increased percentage of CD8(+) T cells and CD56(+) NK cells, CD3(high) T cells and CD45RO(high) CD4(+) T-cell subsets (p < .05). Both H. pylori-infected and noninfected children with gastritis were characterized by an increased percentage of memory/effector CD4(+) T cells, the presence of NK cells with CD56(high), memory T-cell subset with CD4(high), and naive, memory, memory/effector, and effector T-cell subsets with CD8(high) (p < .05). Gastric inflammation scores correlated positively with the percentage of CD4(+) T lymphocytes in H. pylori-infected children (r = .42, p = .03). In noninfected children, gastric inflammation scores correlated positively with the percentage of B cells (r = .45, p = .04).

CONCLUSION

In H. pylori-negative children, gastritis was associated with an increased percentage of activated NK and T cells, and intermediate-differentiated peripheral blood CD4(+) T cells, which was more pronounced in H. pylori-positive children who also showed an increased B-cell response. However, increased inflammation was only associated with the elevation of CD4(+) T-cell percentage in H. pylori-positive children as well as B-cell percentage in H. pylori-negative children with gastritis.

Associations between Helicobacter pylori infection, co-morbid infections, gastrointestinal symptoms, and circulating cytokines in African children

BACKGROUND

Refugee children have complex medical needs and often have multiple infections. The relationship between infection, gastrointestinal symptoms, and systemic inflammation is poorly understood. We investigated these parameters in refugee children with a high prevalence of Helicobacter pylori, helminth, and malaria infection.

MATERIALS AND METHODS

African refugee children were recruited at resettlement health screening. Data were collected on demography, gastrointestinal symptoms, co-morbid infection, and serum for peripheral cytokine levels. Helicobacter pylori infection was diagnosed by a fecal-based immunoassay.

RESULTS

Data from 163 children were analyzed, of which 84.0% were positive for H. pylori. Infected children were significantly older (9.2 years +/- 3.7 vs 7.1 years +/- 3.9, p = .01). Half the cohort (84/163, 51.5%) described gastrointestinal symptoms but these were not strongly associated with co-morbid infections. Helicobacter pylori-infected children had significantly lower circulating log-interleukin-8 (IL-8) (odds ratio 0.61, 95% confidence interval (CI) 0.40, 0.94, p = .025). Helminth infections were common (75/163, 46%) and associated with elevated log-IL-5 (beta: 0.42, 95% CI 0.077, 0.76). Children with malaria (15/163, 9.2%) had elevated log-tumor necrosis factor-alpha (TNFalpha) and log-IL-10 (beta: 0.67, 95% CI 0.34, 1.0 and beta: 1.3, 95% CI 0.67, 1.9, respectively). IL-10 : IL-12 ratios were increased in H. pylori-infected children with malaria or helminth infections. Symptoms were generally not associated with levels of circulating peripheral cytokines irrespective of co-morbid infection diagnosis.

CONCLUSIONS

There is a high prevalence of asymptomatic H. pylori infection in recently resettled African refugee children. Gastrointestinal symptoms were not predictive of H. pylori nor of helminth infections. Serum cytokines, particularly IL-5, IL-10, and TNFalpha, were significantly elevated in children with malaria and helminth infections but not in those with H. pylori infection.

Lactobacilli inhibit interleukin-8 production induced by Helicobacter pylori lipopolysaccharide-activated Toll-like receptor 4

AIM: To investigate the effect of Lactobacillus bulgaricus (LBG) on the Toll-like receptor 4 (TLR4) pathway and interleukin-8 (IL-8) production in SGC-7901 cells treated with Helicobacter pyloriSydney strain 1 lipopolysaccharide (H pyloriSS1-LPS).

METHODS: SGC-7901 cells were treated with H pyloriSS1-LPS in the presence or absence of pretreatment for 1 h with viable LBG or supernatant recovered from LBG culture MRS broth (LBG-_S). Cellular lysates were prepared for Western blot with anti-TLR4, anti-transforming growth factor β-activated kinase 1 (TAK1), anti-phospho-TAK1, anti-nuclear factor κB (NF-κB), anti-p38 mitogen-activated protein kinase (p38MAPK), and anti-phospho-p38MAPK antibodies. The amount of IL-8 in cell culture medium was measured by ELISA.

RESULTS: H pyloriSS1-LPS up-regulated the expression of TLR4, stimulated the phosphorylation of TAK1, subsequently enhanced the activation of NF-κB and the phosphorylation of p38MAPK in a time-dependent manner, leading to augmentation of IL-8 production in SGC-7901 cells. Viable LBG or LBG-_S pretreatment attenuated the expression of TLR4, inhibited the phosphorylation of TAK1 and p38MAPK, prevented the activation of NF-κB, and consequently blocked IL-8 production.

CONCLUSION: H pyloriSS1-LPS induces IL-8 production through activating TLR4 signaling in SGC-7901 cells and viable LBG or LBG-_S prevents H pyloriSS1-LPS-mediated IL-8 production via inhibition of the TLR4 pathway.

Progress of research into the pathogenic mechanism of Helicobacter pylori and the preventive role of probiotics in H. pylori infection

Helicobacter pylori, a highly prevalent pathogen, is a major cause of chronic gastritis and peptic ulcer and a risk factor for gastric malignancies or gastric mucosa-associated lymphoid tissue (MALT) lymphoma. Antibiotic-based H. pylori eradication is currently regarded as the gold standard. However, it is expensive and causes side effects, and the rapid development of antibiotic-resistant strains may soon prevent their large-scale use. Recently, many new therapeutic strategies are being studied to improve the H. pylori eradication rate. The use of probiotics in the field of H. pylori infection has been proposed for improving eradication, tolerability and compliance with multiple antibiotic regimens. In addition, probiotics have a possible role in the stabilization of the gastric barrier function and reducing mucosal inflammation. In this article, we review the development of research on the molecular mechanism of H. pylori infection and the mechanisms of action and clinical significance of probiotics.

Increased interleukin-10 in Helicobacter pylori infection could be involved in the mechanism protecting from allergy

BACKGROUND

A protective effect of Helicobacter pylori infection against allergic diseases has been reported. The increasing incidence of childhood allergy in developed countries may be a result of reduced stimulation of the immune system by early chronic infections, with the protective effect of gastrointestinal microbes being mediated by regulatory T lymphocytes and production of interleukin (IL)-10. To elucidate a possible mechanism involved in protecting against the development of atopy, we measured expression of IL-10 in gastric mucosa of children with H pylori gastritis.

PATIENTS AND METHODS

Gastric biopsies were performed during endoscopy in 48 children (median age, 9 years), 32 of whom had H pylori gastritis and 16 of whom served as controls. Interferon-gamma (IFN-gamma), interleukin-1beta (IL-1beta), and IL-10 were measured in tissue homogenate by quantitative reverse-transcriptase polymerase chain reaction (RT-PCR). The amounts of IFN-gamma, IL-1beta, and IL-10 transcripts were quantified via competitive RT-PCR with use of dilution series of specific competitors.

RESULTS

Expression of IFN-gamma and IL-10 were significantly higher in H pylori-infected children. No direct correlation with age was found, but a further increase in IL-10 expression was found in H pylori-infected children older than 4 years, whereas in control subjects, IL-10 expression tended to be lower in older children. IL-1beta expression was similar in infected children and control subjects. In H pylori-infected children, the prevalence of allergy was significantly higher in children with lower cytokine expression in gastric mucosa.

CONCLUSIONS

In children, H pylori-induced inflammatory response is associated with development of cell-mediated immunity of T-helper 1 type, as demonstrated by increased IFN-gamma expression. The significantly increased expression of gastric IL-10 in H pylori-infected children and its further increase in older children suggest that this chronic infection may influence IL-10 production even beyond the age of 4 years. H pylori may be one of the infections with the potential to modulate immune responses.

Biochemical markers of bone metabolism in children with Helicobacter pylori infection

We investigated the biochemical markers of bone metabolism in children with Helicobacter pylori infection. Biochemical markers of bone metabolism and serum levels of vitamin B12, ferritin and estradiol were measured in 41 H. pylori-positive (+) children (23 girls, 18 boys; aged 11.8+/-3 years). Serum levels of intact parathyroid hormone, ss-collagen I carboxy terminal telopeptide, total alkaline phosphatase (ALP), bone-specific ALP, N-terminal cross-links of human procollagen type I, N-mid-osteocalcin, calcium, phosphate, ferritin, and estradiol did not differ significantly between H. pylori(+) and H. pylori negative (-) children. Vitamin B12 levels were significantly decreased in H. pylori(+) compared to H. pylori(-) children. H. pylori infection was not accompanied by significant changes in markers of bone metabolism in children, although vitamin B12 levels were decreased. Further studies are required to clarify whether H. pylori infection causes time-dependent changes in bone turnover markers during the long course of this inflammatory disease.

Mucosal lymphocyte subsets and HLA-DR antigen expression in paediatric Helicobacter pylori-associated gastritis

Paediatric studies may provide important insights into the immunopathology of Helicobacter pylori-associated gastritis, as mucosal changes reflect different stages of the immunoinflammatory response. We characterized, by quantitative immunohistochemistry, gastric mucosal lymphocyte phenotype and HLA-DR antigen expression and evaluated correlation with histopathology, in H. pylori-infected (Hp+ve) and uninfected children (Hp-ve). In the infected group, lamina propria CD3+ and IgA plasmocyte cell numbers were significantly higher and a trend for predominance of CD8+ over CD4+ was observed both in epithelium and lamina propria. A correlation of inflammation score with lamina propria CD3+ and CD4+ cell numbers and of CD45RO+ T lymphocytes with density of colonization was observed. The proportion of epithelial cells expressing HLA-DR antigen was significantly higher in the Hp+ve group and furthermore, glandular HLA-DR expression correlated with lamina propria CD3+ cell numbers, emphasizing the potential role of epithelial cells as antigen-presenting cells at this stage of infection.