Helicobacter pylori infection up-regulates gland mucous cell-type mucins in gastric pyloric mucosa

Background. Two types of mucous cell are present in gastric mucosa: surface mucous cells (SMCs) and gland mucous cells (GMCs), which consist of cardiac gland cells, mucous neck cells, and pyloric gland cells. We have previously reported that the patterns of glycosylation of SMC mucins are reversibly altered by Helicobacter pylori infection. In this study, we evaluated the effects of H. pylori infection on the expression of GMC mucins in pyloric gland cells. Methods. Gastric biopsy specimens from the antrums of 30 H. pylori‐infected patients before and after eradication of H. pylori and 10 normal uninfected volunteers were examined by immunostaining for MUC6 (a core protein of GMC mucins), α1,4‐N‐acetyl‐glucosaminyl transferase (α4GnT) (the glycosyltransferase which forms GlcNAcα1‐4Galβ‐R), and GlcNAcα1‐4Galβ‐R (a GMC mucin‐specific glycan). Results. MUC6, α4GnT, and HIK1083‐reactive glycan were expressed in the cytoplasm, supranuclear region, and secretory granules in pyloric gland cells, respectively. The immunoreactivity of MUC6 and α4GnT, but not of GlcNAcα1‐4Galβ‐R, in the pyloric gland increased in H. pylori‐associated gastritis, and after the eradication of H. pylori, the increased expression of MUC6 and α4GnT in the gastric mucosa of H. pylori‐infected patients decreased to almost normal levels. This up‐regulation was correlated with the degree of inflammation. Conclusions. In addition to the synthesis of GMC mucins increasing reversibly, their metabolism or release may also increase reversibly in H. pylori‐associated gastritis. The up‐regulation of the expression of gastric GMC mucins may be involved in defense against H. pylori infection in the gastric surface mucous gel layer and on the gastric mucosa.     

Helicobacter pylori and the Surface Mucous Gel Layer of the Human Stomach

Background The colonization of Helicobacter pylori in the surface mucous gel layer (SMGL) was investigated.
Materials and Methods. Surgically removed stomachs were obtained from patients and included gastric ulcer (4 cases), duodenal ulcer (2), and gastric cancer (24). Five of these cases were examined at 8, 19, 28, 143, and 171 days after the end of eradication therapy. For the preservation of the SMGL, these specimens were fixed in cold Carnoy's solution, cleared in xylene, and embedded in paraffin. Serial sections were obtained and were stained by dual staining with the galactose oxidasecold thionin Schiff reaction followed by paradoxical Concanavalin A staining and immunostaining for H. pylori.
Results. H. pylori characterstically attached to surface mucous cells and colonized in the SMGL. H. pylori in the SMGL was more abundant than that attached to the surface mucous cells. The degree of H. pylori infection both on the surface of surface mucous cells and in the SMGL correlated well with the severity of gastritis. In the SMGL, this organism obviously preferred to colonize in the layer of surface mucous cell-type mucins, and the multilaminated structure of the SMGL deteriorated markedly. Eradication of H. pylori restored the structure of the SMGL, and the inflammatory reaction decreased gradually.
Conclusion. The SMGL is an indispensable site of H. pylori colonization, and this organism damaged the gastric mucosa partially by causing deterioration of the SMGL. Removal of the organism from the SMGL should be considered for eradication of this organism.     

Removal of mucus for ultrastructural observation of the surface of human gastric epithelium using pronase

Background. Helicobacter pylori adhering to the human gastric epithelium causes gastric diseases such as ulcer, carcinoma and lymphoma. It is thus important to observe in detail both the surface of the epithelial cells and the H. pylori that adhered to it for the elucidation of H. pylori‐induced diseases by scanning electron microscopy (SEM). Since the thick mucus layer blocks the observation of the cell surface and the bacteria, it is generally eliminated during the processing for SEM by roughly mechanical methods, but these treatments also demolish the ultrastructure of the cells. We studied the nonmechanical method for removal of mucus layer of gastric epithelium using pronase. Materials and Methods. To determine the optimal concentration of pronase, mucin was used as a substrate for inhibition of the viscosity. Pronase was added in 2% mucin at the concentration of 10, 50, 100, 500, 1000, 2000 or 5000 unit/ml and the flowing time of the mixture was measured. Based on the digestion experiment, biopsied specimens from 24 patients with dyspepsic symptoms were fixed in glutaraldehyde and then washed in rolling with different concentration of pronase. After the pretreatment by pronase, the specimens were treated according to the standard process for SEM. Results. We succeeded in removing the mucus layer on the surface of epithelial cells from the biopsied specimens fixed in glutaraldehyde by rinsing with 2000 unit/ml pronase for 24 hours. Conclusions. Using our digestive method without destroying the ultrastructure, the earliest stage which H. pylori has adhered onto the human gastric epithelium can be observed for the investigation of H. pylori‐induced gastric disorders by SEM.     

Effects of selective cyclooxygenase-2 inhibitor and non-selective NSAIDs on Helicobacter pylori-induced gastritis in Mongolian gerbils

Background. It is still a point of controversy whether Helicobacter pylori‐infected patients are more likely to develop mucosal damage while taking NSADIs. Selective cyclooxygenase (COX‐2) inhibitors may be associated with less severe gastric mucosal damage than conventional NSAIDs, but this association is undefined in H. pylori‐induced gastritis. The aim of this study was to evaluate the effects of selective COX‐2 and nonselective NSAIDs on H. pylori‐induced gastritis. Methods. After intragastric administration of indomethacin, NS‐398 or vehicle alone, once daily for 5 days in H. pylori‐infected and uninfected Mongolian gerbils, we evaluated gastric mucosal damage, inflammatory cell infiltration and prostaglandin E₂ (PGE₂) concentration. We investigated whether H. pylori infection induced the COX‐2 expression. Results. In H. pylori‐uninfected groups, the indomethacin‐treated group showed the highest mucosal damage score and the lowest PGE₂ concentration. There was no difference in mucosal damage scores and PGE₂ concentration between NS‐398 and vehicle‐alone treated group. In H. pylori‐infected groups, there was no difference in mucosal damage scores, irrespective of the type of drugs administered. The indomethacin‐treated group showed the lowest PGE₂ concentration, similar to that of the NS‐398 and vehicle‐alone treated groups, both without H. pylori infection. Gastric neutrophil and monocyte infiltration scores were higher in H. pylori‐infected groups than in uninfected groups. However, there was no difference in these scores according to the type of drugs administered, within H. pylori‐infected or uninfected groups. COX‐2 protein expression was observed in H. pylori‐infected Mongolian gerbils but not in uninfected ones. Conclusions. Our animal study showed that H. pylori infection induced COX‐2 expression and increased prostaglandin concentration. Administration of NSAIDs decreased the prostaglandin concentration, but did not increase mucosal damage in H. pylori‐induced gastritis. Selective COX‐2 inhibitors, instead of conventional NSIADs, had no beneficial effect on preventing mucosal damage in H. pylori‐induced gastritis.     

Vitamin C and E supplements to lansoprazole-amoxicillin-metronidazole triple therapy may reduce the eradication rate of metronidazole-susceptible Helicobacter pylori infection

Aim. To test whether vitamin C and E supplements to triple therapy can improve the Helicobacter pylori eradication rate and gastric inflammation. Methods. A total of 104 H. pylori‐infected patients were randomized to receive: either lansoprazole, amoxicillin, and metronidazole twice daily for 1 week (triple‐only group) or lansoprazole, amoxicillin, metronidazole plus vitamin C (250 mg) and vitamin E (200 mg) twice daily for 1 week, followed immediately by vitamin C and E once daily for 6 consecutive weeks (triple‐plus‐vitamin group). Eight weeks after the completion of triple therapy, patients were assessed for the effectiveness of H. pylori eradication. The severity of gastric inflammation in histology was assessed for the acute and chronic inflammation scores. Results. Intention‐to‐treat and per‐protocol eradication rates were 59.1% and 64.4% in the triple‐only group, and 40% and 44% in the triple‐plus‐vitamin group. In the patients infected with metronidazole susceptible isolates, the triple‐only group had a higher intention‐to‐treat eradication rate than those in the triple‐plus‐vitamin group (80% vs. 53.1%, p < .01). However, for the metronidazole resistance isolates, the intention‐to‐treat eradication rates between the two groups were not different (26.3% vs. 21.7%, p = NS). The improvements of both acute and chronic inflammation scores in histology were not different between the two groups. Conclusion. Adding vitamin C and E to triple therapy cannot improve the H. pylori eradication rate and gastric inflammation. For patients with metronidazole susceptible strain infection, adding these vitamins may even reduce the eradication rate of triple therapy.     

Effects of aspirin on the development of Helicobacter pylori-induced gastric inflammation and heterotopic proliferative glands in Mongolian gerbils

Background: Helicobacter pylori infection is a major cause of gastritis and gastric carcinoma. Aspirin has anti‐inflammatory and antineoplastic activity. The aim of the present study was to determine the effects of aspirin on H. pylori‐induced gastritis and the development of heterotopic proliferative glands. Methods: H. pylori strain SS1 was inoculated into the stomachs of Mongolian gerbils. Two weeks after inoculation, the animals were fed with the powder diets containing 0 p.p.m. (n = 10), 150 p.p.m. (n = 10), or 500 p.p.m. (n = 10) aspirin. Mongolian gerbils were killed after 36 weeks of infection. Uninfected Mongolian gerbils (n = 10) were used as controls. Histologic changes, epithelial cell proliferation and apoptosis, and prostaglandin E₂ (PGE₂) levels of gastric tissue were determined. Results: H. pylori infection induced gastric inflammation. Administration of aspirin did not change H. pylori‐induced gastritis, but alleviated H. pylori‐induced hyperplasia and the development of heterotopic proliferative glands. Administration of aspirin accelerated H. pylori‐associated apoptosis but decreased H. pylori‐associated cell proliferation. In addition, the increased gastric PGE₂ levels due to H. pylori infection were suppressed by treatment with aspirin, especially at the dose of 500 p.p.m. Conclusions: Aspirin alleviates H. pylori‐induced hyperplasia and the development of heterotopic proliferative glands. Moreover, aspirin increases H. pylori‐induced apoptosis. We demonstrated the antineoplastic activities of aspirin in H. pylori‐related gastric carcinogenesis.     

Increased gastric osteopontin expression by Helicobacter pylori Infection can correlate with more severe gastric inflammation and intestinal metaplasia

Background: Osteopontin (OPN) is involved in the gastric cancer progression. The study validated whether OPN expressions correlate with Helicobacter pylori‐related chronic gastric inflammation and the precancerous change as intestinal metaplasia (IM). Methods: This study included 105 H. pylori‐infected patients (63 without and 42 with IM) and 29 H. pylori‐negative controls. In each subject, the gastric OPN expression intensity was evaluated by immunohistochemistry, and graded from 0 to 4 for the epithelium, lamina propria, and areas with IM, respectively. For the H. pylori‐infected subjects, the gastric inflammation was assessed by the Updated Sydney System. Forty‐nine patients received follow‐up endoscopy to assess OPN change on gastric mucosa after H. pylori eradication. The in vitro cell‐H. pylori coculture were performed to test the cell origin of OPN. Results: The H. pylori‐infected patients had higher gastric OPN expression than the noninfected controls (p < .001). For the H. pylori‐infected patients, an increased OPN expression correlated with more severe chronic gastric inflammation (p < .001) and the presence of IM (OR: 2.6, 95% CI: 1.15–5.94, p = .02). Within the same gastric bits, lamina propria expressed OPN stronger than epithelium (p < .001), suggesting OPN predominantly originates from inflammatory cells. The in vitro assay confirmed H. pylori stimulate OPN expression in the monocytes, but not in the gastric epithelial cells. After H. pylori eradication, the gastric OPN expression could be decreased only in areas without IM (p < .05). Conclusions: Increased gastric OPN expression by H. pylori infection can correlate with a more severe gastric inflammation and the presence of IM.     

Preventive effects of Cladosiphon fucoidan against Helicobacter pylori infection in Mongolian gerbils

Background. Recently, the acquisition by Helicobacter pylori of resistance to antibiotics has become a serious problem. Therefore, nonantibiotic substances are required to diminish H. pylori‐induced gastric lesions. In the present study, the effects of Cladosiphon fucoidan were examined in terms of H. pylori attachment to porcine gastric mucin in vitro and Helicobacter pylori‐induced gastritis in vivo. Methods. The inhibitory effect of Cladosiphon fucoidan and other polysaccharides on H. pylori attachment to porcine gastric mucin was assayed in vitro with mucin‐coated microtiter plates. The effect of Cladosiphon fucoidan on H. pylori‐induced gastritis was examined in vivo using Mongolian gerbils. H. pylori‐inoculated gerbils were given fucoidan in drinking water. Six weeks after H. pylori‐inoculation, gerbils were sacrificed for macroscopic and microscopic examination of gastric lesions and counting of viable H. pylori in the gastric mucosa. Results. Cladosiphon fucoidan inhibited the H. pylori attachment to porcine gastric mucin at pH 2.0 and 4.0. Two other sulfated polysaccharides, Fucus fucoidan and dextran sulfate sodium, also inhibited the attachment but only at pH 2.0. Inhibitory effects of these three sulfated polysaccharides were not observed at pH 7.2 and nonsulfated polysaccharides, such as mannan and dextran, exerted no influence at any pH. In the in vivo experiment, the H. pylori‐induced gastritis and the prevalence of H. pylori infected animals were markedly reduced by fucoidan in a dose‐dependent manner, at doses of 0.05 and 0.5% in the drinking water. Conclusion. Cladosiphon fucoidan may deserve particular attention as a safe agent that can prevent H. pylori infection and reduce the risk of associated gastric cancer.     

Mechanism of action of low recurrence of gastritis caused by Helicobacter pylori with the type II urease B gene

Background. Low recurrence of gastritis is seen in patients infected with Helicobacter pylori carrying the type II urease B gene, compared with H. pylori carrying types I and III. The underlying mechanism has been studied in terms of the urease activity and interleukin (IL)‐8 production capacity of different strains of H. pylori. Materials and Methods. Forty‐five patients infected with different strains of H. pylori (type I; 15, type II; 15 and type III; 15) were enrolled in the study. H. pylori was isolated from gastric mucosa and cultured in the presence of urea at pH 5.5 to evaluate urease activity. The capacity of different strains of H. pylori to induce IL‐8 mRNA and IL‐8 from a human gastric cancer cell line and human peripheral blood mononuclear cells was evaluated. Results. The urease activity of type II H. pylori[523 ± 228 µg of ammonia/dl/10⁸ colony‐forming units (CFU)/ml] was significantly lower than that of type I (1355 ± 1369 µg of ammonia/dl/10⁸ CFU/ml) and type III (1442 ± 2229 µg of ammonia/dl/10⁸ CFU/ml) (p < .05). Gastric cancer cells cocultured with type II H. pylori produced lower levels of IL‐8 mRNA compared with type I and type III H. pylori. The levels of IL‐8 were also significantly lower in cultures induced by type II H. pylori compared with those induced by type I and type III H. pylori. Peripheral blood mononuclear cells also produced lower levels of IL‐8 when cocultured with type II compared with type I H. pylori. Conclusions. These results indicate that both the lower level of urease activity and the low IL‐8‐inducing capacity of type II H. pylori might underlie the lower recurrence rate of gastritis caused by type II H. pylori.     

Increased primary resistance to recommended antibiotics negatively affects Helicobacter pylori eradication

Objective. To evaluate the efficacy of two commonly employed treatments for Helicobacter pylori infection and the impact of bacterial resistance to antibiotics on eradication rate. Methods. Ninety‐two consecutive H. pylori‐positive patients with active peptic ulcer disease were randomly enrolled to receive a 7‐day treatment with either lansoprazole 30 mg plus amoxicillin 1 g and clarithromycin 500 mg [all twice a day (b.i.d.), Group A, n = 46]; or bismuth subcitrate 125 mg four times a day (q.i.d.) plus tetracycline 500 mg q.i.d and furazolidone 200 mg b.i.d. (Group B, n = 46) H. pylori status was reassessed 30 days after completion of the therapy and bacterial resistance to the antibiotics was investigated using an in vitro assay. Results. Five patients from each study group were lost to follow up. Both treatments resulted in similar H. pylori eradication rate: 66–60% (per protocol), 59–52% (intention‐to‐treat) in Groups A and B, respectively (non significant). However, eradication improved to 79% in the absence of H. pylori resistance to clarithromycin or amoxicillin. Conclusion. Primary resistance to clarithromycin or amoxicillin may underscore a potentially serious problem for the eradication of H. pylori infection. Testing for bacterial resistance may become necessary to improve therapeutic efficacy.     

Rank order of success favors longer duration of imidazole-based therapy for Helicobacter pylori in duodenal ulcer disease: a randomized pilot study

Background. Studies on eradication therapy in developing countries have shown a success rate of 70–85%, which is suboptimal. Duration of therapy may be an important factor dictating eradication success in such regions. Aim. The study was undertaken to evaluate the effect of increasing the treatment period on eradication of Helicobacter pylori in duodenal ulcer disease. Methods. A randomized trial was carried out in which 64 consecutive H. pylori‐infected patients with duodenal ulcer disease were enrolled. The patients were randomized to one of the three trial arms. Therapy consisted of lansoprazole 30 mg twice a day (b.i.d.), amoxycillin 1 g b.i.d. and tinidazole 500 mg b.i.d. The treatment period was 1 week in group I, 2 weeks in group II and 3 weeks in group III. At inclusion, patients underwent endoscopy and the presence of H. pylori was documented by a positive urease test and C14 urea breath test. Four weeks after completion of eradication therapy, the patients were subjected to repeat endoscopy to assess ulcer healing and tests for H. pylori infection. Results. Sixty‐four patients (55 male and nine female; mean age 35.5 years) were enrolled in each group. The H. pylori eradication rate for group I (1 week of therapy) was 47.6%, that for group II (2 weeks of therapy) was 80%, and that for group III (3 weeks of therapy) was 91.3% (p = .003). The ulcer healing rates were 71.4, 80 and 95.6% in groups I, II and III, respectively (p = .09). Conclusion. The 3‐week regimen significantly improved the eradication rate as compared with the 1‐week regime. Increasing the duration of therapy significantly improved the chances of eradication of H. pylori in duodenal ulcer disease.     

The effects of nocturnal acid breakthrough on Helicobacter pylori eradication

Background. The effects of nocturnal gastric acid breakthrough (NAB) on Helicobacter pylori eradication are still unknown in peptic ulcer patients. The purposes of this study were to compare the effect of lansoprazole 30 mg twice a day (bid) to lansoprazole 60 mg once a day (qd) on the prevalence of NAB, and to determine whether NAB affects the eradication of H. pylori in peptic ulcer patients. Methods. Experiments were carried out in 67 patients with H. pylori‐positive peptic ulcers. They were randomized into two groups, one treated with a combination of lansoprazole 60 mg, clarithromycin 1.0 g, and amoxycillin 2.0 g once a day before breakfast (qd group), and the other, divided doses of the drugs were given before breakfast and dinner (bid group) for 2 weeks. Results. NAB occurred in 31 patients, 55.2% in qd group, and 39.5% in bid group (p = .226). H. pylori eradication was achieved in 61.3% in NAB positive group and 83.3% in NAB negative group (p = .055). The mean duration of NAB for H. pylori eradication group was 99.3 ± 22.7 min, and 293.2 ± 49.8 min for H. pylori persistence group (p < .05). The median intragastric pH of the H. pylori eradication and persistence group was 5.7 ± 0.2 and 4.2 ± 0.4, respectively (p < .05). Conclusions. Neither the morning dose and the divided dose regimen of lansoprazole affected the intragastric acidity and occurrence of the NAB. NAB did not influence H. pylori eradication in peptic ulcer patients, but the duration of NAB and total intragastric median pH were found to influence the H. pylori eradication.     

Age at acquisition of Helicobacter pylori in a pediatric Canadian First Nations population

Background. Few data exist regarding the epidem‐iology of Helicobacter pylori infections in aboriginal, including the First Nations (Indian) or Inuit (Eskimo) populations of North America. We have previously found 95% of the adults in Wasagamack, a First Nations community in Northeastern Manitoba, Canada, are seropositive for H. pylori. We aimed to determine the age at acquisition of H. pylori among the children of this community, and if any association existed with stool occult blood or demographic factors. Materials and Methods. We prospectively enrolled children resident in the Wasagamack First Nation in August 1999. A demographic questionnaire was administered. Stool was collected, frozen and batch analyzed by enzyme‐linked immunosorbent assay (ELISA) for H. pylori antigen and for the presence of occult blood. Questionnaire data were analyzed and correlated with the presence or absence of H. pylori. Results. 163 (47%) of the estimated 350 children aged 6 weeks to 12 years, resident in the community were enrolled. Stool was positive for H. pylori in 92 (56%). By the second year of life 67% were positive for H. pylori. The youngest to test positive was 6 weeks old. There was no correlation of a positive H. pylori status with gender, presence of pets, serum Hgb, or stool occult blood. Forty‐three percent of H. pylori positive and 24% of H. pylori negative children were < 50th percentile for height (p = 0.024). Positive H. pylori status was associated with the use of indoor pail toileting (86/143) compared with outhouse toileting (6/20) (p = 0.01). Conclusions. In a community with widespread H. pylori infection, overcrowded housing and primitive toileting, H. pylori is acquired as early as 6 weeks of age, and by the second year of life 67% of children test positive for H. pylori.     

Immunohistochemical Detection of Helicobacter pylori in the Surface Mucous Gel Layer and Its Clinicopathological Significance

Background Attempts have been made to develop an accurate method for detecting Helicobacter pylori in histological sections.
Materials and Methods. Biopsy specimens were obtained from the stomachs of 167 patients with gastric ulcer (33), duodenal ulcer (52), gastroduodenal ulcer (15), chronic gastritis (45), and normal mucosa (22) before antimicrobial treatment and from 108 of these patients after treatment. Biopsy specimens were (1) cultured, (2) fixed in 10% buffered formalin, or (3) fixed in Carnoy's solution. The latter method was employed to preserve the surface mucous gel layer (SMGL) covering gastric surface mucous cells. Histological sections were stained with hematoxylin and eosin (H&E), with immunostaining using a commercially available polyclonal anti- H. pylori antibody.
Results. Cultures were positive for H. pylori in 61% of the cases before treatment and in 16% after treatment; by H&E staining using formalin-fixed materials: 70% and 9%; by immunostaining using formalin-fixed materials: 78% and 21%; and by immunostaining using Carnoy-fixed materials: 85% and 41% of biopsy speciemens, respectively. The difference in detection rates between materials fixed in formalin and those in Carnoy's solution was due to the detection of H. pylori in the SMGL by the latter, especially after antimicrobial treatment.
Conclusions. Immunostaining for H. pylori using materials fixed in Carnoy's solution revealed H. pylori in the SMGL as well as on the surface mucous cells and in the gastric pits and permitted the optimal detection of H. pylori in tissue sections.     

Role of Immune Serum in the Killing of Helicobacter pylori by Macrophages

Background: Helicobacter pylori infection can lead to the development of gastritis, peptic ulcers and gastric cancer, which makes this bacterium an important concern for human health. Despite evoking a strong immune response in the host, H. pylori persists, requiring complex antibiotic therapy for eradication. Here we have studied the impact of a patient’s immune serum on H. pylori in relation to macrophage uptake, phagosome maturation, and bacterial killing. Materials and Methods: Primary human macrophages were infected in vitro with both immune serum‐treated and control H. pylori. The ability of primary human macrophages to kill H. pylori was characterized at various time points after infection. H. pylori phagosome maturation was analyzed by confocal immune fluorescence microscopy using markers specific for H. pylori, early endosomes (EEA1), late endosomes (CD63) and lysosomes (LAMP‐1). Results: Immune serum enhanced H. pylori uptake into macrophages when compared to control bacteria. However, a sufficient inoculum remained for recovery of viable H. pylori from macrophages, at 8 hours after infection, for both the serum‐treated and control groups. Both serum‐treated and control H. pylori phagosomes acquired EEA1 (15 minutes), CD63 and LAMP‐1 (30 minutes). These markers were then retained for the rest of an 8 hour time course. Conclusions: While immune sera appeared to have a slight positive effect on bacterial uptake, both serum‐treated and control H. pylori were not eliminated by macrophages. Furthermore, the same disruptions to phagosome maturation were observed for both serum‐treated and control H. pylori. We conclude that to eliminate H. pylori, a strategy is required to restore the normal process of phagosome maturation and enable effective macrophage killing of H. pylori, following a host immune response.     

Second-line Helicobacter pylori eradication: a randomized comparison of 1-week or 2-week bismuth-containing quadruple therapy

Objectives: The increasing levels of bacterial antibiotic resistance have increased the need to evaluate the second‐line treatments for Helicobacter pylori. Bismuth‐based quadruple therapy is recommended as a second‐line treatment, but the optimal duration of this treatment is still debatable. We prospectively analyzed the eradication rate of H. pylori according to the duration of the second‐line bismuth‐based quadruple therapy. Methods: One hundred and ninety‐nine patients who failed at H. pylori eradication were prospectively randomized to receive pantoprazole 40 mg twice daily, metronidazole 500 mg thrice daily, and bismuth subcitrate 300 mg and tetracycline 500 mg four times daily for 7 days (PBMT7) or for 14 days (PBMT14). The post‐treatment H. pylori status was determined by the ¹³C‐urea breath test. The eradication rates, drug compliance, and side effects of each group were evaluated. Results: The intention‐to‐treat (ITT) eradication rates were 81.6% (95% CI 73.9–89.3%, 80/98) in the PBMT7 arm and 85.1% (95% CI 78.2–92.0%, 86/101) in the PBMT14 arm (p = .028, noninferiority test), while the per‐protocol (PP) eradication rates were 89.6% (95% CI 83.2–96.0%, 78/87) and 96.2% (95% CI 92.0–100.0% 77/80) (p = .015, noninferiority test), respectively. The compliance was 88.8% (87/98) and 79.2% (80/101) in the PBMT7 and PBMT14 groups, respectively. (p = .066) The number of patients having severe side effects was 15.3% (15/98) and 21.8% (22/101) in the PBMT7 and PBMT14 groups, respectively, which was similar between both groups. (p = .243). Conclusions: Although PBMT7 was not inferior to PBMT14 statistically, PBMT could not demonstrate enough ITT/PP eradication rate. Therefore, it could be better to extend the duration of treatment for 2 weeks for the second‐line treatment of H. pylori in Korea.     

The Interaction Between Helicobacter pylori and Atopy: Does Inverse Association Really Exist?

Aim: To date, cross‐sectional and case–control studies suggest an inverse association between Helicobacter pylori infection and atopic diseases, whereas the immunologic basis has not been studied yet. In this study we investigated T helper (Th) cell function in H. pylori‐infected children and compared cytokine responses in atopic and non‐atopic groups. Methods: The study groups was recruited from a cohort of 327 healthy children evaluated and followed‐up for 6 years to assess the natural history of H. pylori infection. Seventy‐four of 136 healthy children who underwent ¹³C urea breath test were eligible and accepted to participate. All participants were evaluated by a questionnaire, and skin‐prick testing. According to the results, children were divided into four groups with respect to the presence or absence of H. pylori and atopy. Peripheral blood mononuclear cells isolated from 34 of 74 children were cultured with H. pylori, Der p 1, and phytohemagglutinin (PHA). Interferon‐gamma (IFN‐γ), interleukin (IL)‐4 and IL‐10, transforming growth factor‐beta (TGF‐β) levels were measured in supernatants. Results: The frequency of atopy was lower in H. pylori‐infected group (31.9% vs. 48.1, p = .22), while atopic symptoms were similar between infected and non‐infected children. While PHA and H. pylori induced IFN‐γ levels were significantly higher in H. pylori‐infected children, concomitant presence of both atopy and H. pylori decreased the level of PHA and H. pylori induced IFN‐γ production. PHA and Der p 1‐induced IL‐4 levels were higher in atopic children, and IL‐4 production was suppressed when they were concomitantly infected with H. pylori. The production of TGF‐β was found to be suppressed in atopic children irrespective of the presence of H. pylori infection. Conclusion: The results of the current study demonstrated a counteractive Th1 and Th2 cytokine interaction between H. pylori infection and atopy. However, this counteractive immunologic balance did not protect against atopy.     

Effect of Helicobacter pylori infection on gastric acid secretion and meal-stimulated serum gastrin in children

Background. Comparative studies of gastric acid secretion in children related to Helicobacter pylori infection are lacking. The purpose of this study was to compare acid secretion and meal‐stimulated gastrin in relation to H. pylori infection among pediatric patients. Materials and Methods. Thirty‐six children aged 10–17 years (17 with H. pylori infection) undergoing diagnostic endoscopy participated in the study. Diagnoses included gastritis only (n = 23), duodenal ulcer (n = 5) and normal histology (n = 8). Gastric acid output was studied using the endoscopic gastric secretion test before and 2–3 months after H. pylori eradication. Meal‐stimulated serum gastrin response was assessed before and 12 months after eradication. Results. H. pylori gastritis was typically antrum‐predominant. Acid secretion was greater in H. pylori‐positive patients with duodenal ulcer than in gastritis‐only patients or controls [mean ± standard error (SE): 6.56 ± 1.4, 3.11 ± 0.4 and 2.65 ± 0.2 mEq/10 minutes, respectively; p < .001]. Stimulated acid secretion was higher in H. pylori‐positive boys than girls (5.0 ± 0.8 vs. 2.51 ± 0.4 mEq/10 minutes, respectively; p < .05). Stimulated acid secretion pre‐ and post‐H. pylori eradication was similar (5.47 ± 0.8 vs. 4.67 ± 0.9 mEq/10 minutes, respectively; p = .21). Increased basal and meal‐stimulated gastrin release reversed following H. pylori eradication (e.g. basal from 134 to 46 pg/ml, p < .001 and peak from 544 to 133 pg/ml, p < .05). Conclusions. H. pylori infection in children is associated with a marked but reversible increase in meal‐stimulated serum gastrin release. Gastric acid hypersecretion in duodenal ulcer remains after H. pylori eradication, suggesting that the host factor plays a critical role in outcome of the infection.     

Investigation of the immunomodulatory effects of Lactobacillus casei and Bifidobacterium lactis on Helicobacter pylori infection

Background: Lactobacillus and Bifidobacterium species have shown beneficial effects in the treatment of Helicobacter pylori infection; however, the mechanisms behind such effects are not fully understood. In this study, we have investigated the immunomodulatory effects of probiotics in a mouse model of H. pylori infection. Materials and methods: H. pylori‐infected C57BL/6 mice were treated with L. casei L26, B. lactis B94, or no probiotics for 5 weeks, respectively. Mice not infected with H. pylori were included as normal controls. Gastric histology, protein levels of interleukin (IL)‐1β, IL‐10, IL‐12/23p40, and H. pylori colonization density in the gastric tissues, as well as H. pylori‐specific antibodies were examined. Results: In mice receiving L. casei L26 and B. lactis B94, gastric neutrophil infiltration and IL‐1β were significantly decreased and IL‐10 was significantly increased as compared with mice receiving no probiotics. In mice receiving B. lactis B94, IL‐12/23p40 was significantly increased and H. pylori IgG was significantly reduced as compared with mice receiving no probiotics. No significant difference of H. pylori colonization was observed among the three groups of mice. Conclusion: The reduced level of IL‐1β and neutrophil infiltration observed in mice infected with H. pylori following treatment with L. casei L26 and B. lactis B94 resulted from a modulation of immune response rather than a decrease of H. pylori colonization. Furthermore, B. lactis B94 has the intrinsic ability to promote a Th1 immune response through an increase in IL‐12/IL‐23.     

NOD1 is required for Helicobacter pylori induction of IL‐33 responses in gastric epithelial cells

Helicobacter pylori (H. pylori) causes chronic inflammation which is a key precursor to gastric carcinogenesis. It has been suggested that H. pylori may limit this immunopathology by inducing the production of interleukin 33 (IL‐33) in gastric epithelial cells, thus promoting T helper 2 immune responses. The molecular mechanism underlying IL‐33 production in response to H. pylori infection, however, remains unknown. In this study, we demonstrate that H. pylori activates signalling via the pathogen recognition molecule Nucleotide‐Binding Oligomerisation Domain‐Containing Protein 1 (NOD1) and its adaptor protein receptor‐interacting serine–threonine Kinase 2, to promote production of both full‐length and processed IL‐33 in gastric epithelial cells. Furthermore, IL‐33 responses were dependent on the actions of the H. pylori Type IV secretion system, required for activation of the NOD1 pathway, as well as on the Type IV secretion system effector protein, CagA. Importantly, Nod1^+/+ mice with chronic H. pylori infection exhibited significantly increased gastric IL‐33 and splenic IL‐13 responses, but decreased IFN‐γ responses, when compared with Nod1^?/? animals. Collectively, our data identify NOD1 as an important regulator of mucosal IL‐33 responses in H. pylori infection. We suggest that NOD1 may play a role in protection against excessive inflammation.