A novel in vitro infection model of Helicobacter pylori using mucin-producing murine gastric surface mucous cells

BACKGROUND: Helicobacter pylori is found within the gastric surface mucous gel layer and in the epithelial surface. Gastric cancer cells have been used in experimental H. pylori infection in vitro, although cancer cells have some abnormalities in cellular properties. The aim of this study was to develop an in vitro H. pylori infection model using normal gastric surface cells that produce gastric mucin. MATERIALS AND METHODS: Normal murine gastric surface mucous cells (GSM06) were cultured by the liquid interface method using a serum-free medium and a collagen gel containing a fibroblast cell line (L929) and infected with H. pylori. Infection by H. pylori was assessed by enumerating the colony-forming units (CFU) of H. pylori adhered to GSM06 cells and by transmission electron microscopy. The production of mucin was determined by a lectin binding assay, sugar analysis, and MUC5AC gene expression. RESULTS: GSM06 cells cultured under these conditions produced mucin containing N-acetylgalactosamine and MUC5AC as the core protein. Significantly higher numbers of H. pylori adhered to GSM06 cells under mucin-producing conditions than under nonproducing conditions. Microscopic observation showed a filamentous structure resembling a type IV secretion system apparatus formed between the surface of GSM06 cells and H. pylori. CONCLUSIONS: This study demonstrates a novel in vitro H. pylori infection model using mucin-producing murine GSM06 cells for early stages of infection.     

mRNA expression of cytokines and chemokines in the normal gastric surface mucous epithelial cell line GSM06 during bacterial infection with Helicobacter felis.

BACKGROUND AND AIM: A group of the proinflammatory and chemotactic cytokines (chemokines) has been considered as an important factor in the pathomechanism of different bacterial diseases, among them the common Helicobacter pylori infection. Experimental results obtained with gastric biopsy samples of H. pylori positive patients, and with H. pylori infected tumor originated gastric cell lines indicated that these cytokines have essential roles in the development and maintenance of the immune response and inflammation of the gastric mucosa during H. pylori infection. Although the mRNA expression was shown in these biopsy samples and cell lines, it is not yet proved that the normal gastric mucosal epithelial cells themselves express these cytokines. The establishment of a gastric surface mucous cell line with non-tumor origin (GSM06), and the usage of Helicobacter felis as a model of the classic H. pylori infection gave us the possibility to check this question. MATERIALS AND METHODS: in this study GSM06 cells were infected with different numbers (10(5), 10(6), 10(7), 10(8), 10(9) bacterium/ml medium) of H. felis for two different time periods (2, 4 h). Cells treated with medium only were used as control. Then the mRNA expression of the following cytokines was measured by RT-PCR method in the GSM06 cells: proinflammatory cytokine IL1-beta, and chemokine RANTES, eotaxin, MCP-1, MIP1-alpha and MIP1-beta. RESULTS: we found that neither mRNA of the investigated cytokines was expressed constitutively, however the GSM06 cells expressed the mRNA of each cytokine during H. felis infection. CONCLUSION: our results prove that normal gastric surface mucous epithelial cells express immunologically active peptides during H. felis infection. We may suppose that the epithelial cells of the gastric mucosa contribute to the immune response and inflammation by expressing proinflammatory (IL1-beta) and chemotactic (RANTES, eotaxin, MCP-1, MIP1-alpha and beta) cytokines during H. pylori infection in human.     

Toll-like receptor (TLR) 2 induced through TLR4 signaling initiated by Helicobacter pylori cooperatively amplifies iNOS induction in gastric epithelial cells

Cell-surface Toll-like receptors (TLRs) initiate innate immune responses, such as inducible nitric oxide synthase (iNOS) induction, to microorganisms' surface pathogens. TLR2 and TLR4 play important roles in gastric mucosa infected with Helicobacter pylori (H. pylori), which contains lipopolysaccharide (LPS) as a pathogen. The present study investigates their physiological roles in the innate immune response of gastric epithelial cells to H. pylori-LPS. Changes in the expression of iNOS, TLR2, and TLR4, as well as downstream activation of mitogen-activated protein kinases and nuclear factor-kappaB (NF-kappaB), were analyzed in normal mouse gastric mucosal GSM06 cells following stimulation with H. pylori-LPS and interferon-gamma. Specific inhibitors for mitogen-activated protein kinases, NF-kappaB, and small interfering RNA for TLR2 or TLR4 were employed. The immunohistochemistry of TLR2 was examined in human gastric mucosa. H. pylori-LPS stimulation induced TLR2 in GSM06 cells, but TLR4 was unchanged. TLR2 induction resulted from TLR4 signaling that propagated through extracellular signal-related kinase and NF-kappaB activation, as corroborated by the decline in TLR4 expression on small interfering RNA treatment and pretreatment with inhibitors. The induction of iNOS and the associated nitric oxide production in response to H. pylori-LPS stimulation were inhibited by declines in not only TLR4 but also TLR2. Increased expression of TLR2 was identified in H. pylori-infected human gastric mucosa. TLR4 signaling initiated by H. pylori-LPS and propagated via extracellular signal-regulated kinase and NF-kappaB activation induced TLR2 expression in gastric epithelial cells. Induced TLR2 cooperated with TLR4 to amplify iNOS induction. This positive correlation may constitute a mechanism for stimulating the innate immune response against various bacterial pathogens, including H. pylori-LPS.     

Nutrients released by gastric epithelial cells enhance Helicobacter pylori growth

BACKGROUND: Helicobacter pylori survives and proliferates in the human gastric mucosa. In this niche, H. pylori adheres to the gastric epithelial cells near the tight junctions. In vitro, H. pylori proliferated well in tissue-culture medium near gastric epithelial cells. However, in the absence of epithelial cells, growth of H. pylori could only be established in tissue-culture medium when, prior to the experiment, it was preincubated near gastric epithelial cells. Therefore, we aimed to determine whether diffusion of nutrients derived from epithelial cells was required for H. pylori growth in Dulbecco's modified Eagle's minimal essential medium (DMEM) cell culture medium. MATERIALS AND METHODS: Cell culture conditions essential for H. pylori growth in vitro were determined with gastric epithelial HM02 cells. RESULTS: Deprivation of iron in cell-culture-conditioned DMEM resulted in a growth arrest of H. pylori. However, near gastric epithelial cells, growth of H. pylori was resistant to iron deprivation. Evidently, when residing close to epithelial cells, H. pylori was able to fulfil its iron requirements, even when the DMEM was deprived of iron. Nevertheless, supplementation with iron alone did not restore H. pylori growth in DMEM, hence other nutrients were deficient as well in the absence of epithelial cells. Growth of H. pylori in DMEM was restored when hypoxanthine, L-alanine and L-proline were added to the DMEM. CONCLUSIONS: Diffusion of (precursors of) these nutrients from the gastric epithelial cells is essential for H. pylori growth in vitro. We hypothesize that in vivo, H. pylori favors colonization near the tight junctions, to gain maximal access to the nutrient(s) released by gastric epithelial cells.     

Inhibition of Helicobacter pylori colonization by sulfated gastric mucin.

The role of human gastric mucin in mucosal protection against Helicobacter pylori colonization was investigated. H. pylori cells were incubated with purified intact mucin or its acidic fractions and then examined for their inhibitory capacity of H. pylori attachment to erythrocytes. Titration data established that the inhibitory activity of mucin was associated with its acidic component as the fraction enriched in sialic acid and sulfate showed 16-fold higher inhibitory titer than that of the intact mucin. While the inhibitory titer of acidic mucin fraction was not affected by the removal of sialic acid, the desulfation led to a complete loss of its inhibitory activity, thus pointing towards the importance of sulfate ester groups in this process. The results for the first time point towards the involvement of sulfomucins in the protection of gastric mucosa against colonization by H. pylori.     

Helicobacter pylori induce neutrophil transendothelial migration: role of the bacterial HP-NAP

Continuous recruitment of neutrophils into the inflamed gastric mucosal tissue is a hallmark of Helicobacter pylori infection in humans. In this study, we examined the ability of H. pylori to induce transendothelial migration of neutrophils using a transwell system consisting of a cultured monolayer of human endothelial cells as barrier between two chambers. We showed for the first time that live H. pylori, but not formalin-killed bacteria, induced a significantly increased transendothelial migration of neutrophils. H. pylori conditioned culture medium also induced significantly increased transendothelial migration, whereas heat-inactivated culture filtrates had no effect, suggesting that the chemotactic factor was proteinaceous. Depletion of H. pylori-neutrophil activating protein (HP-NAP) from the culture filtrates resulted in significant reduction of the transmigration. Culture filtrates from isogenic HP-NAP deficient mutant bacteria also induced significantly less neutrophil migration than culture filtrates obtained from wild-type bacteria. HP-NAP did not induce endothelial cell activation, suggesting that HP-NAP acts directly on the neutrophils. In conclusion, our results demonstrate that secreted HP-NAP is one of the factors resulting in H. pylori induced neutrophil transendothelial migration. We propose that HP-NAP contributes to the continuous recruitment of neutrophils to the gastric mucosa of H. pylori infected individuals.     

Eradication of Helicobacter pylori infection favourably affects altered gastric mucosal MMP-9 levels

BACKGROUND: Helicobacter pylori gastritis is recognized as an important pathogenetic factor in peptic ulcer disease and gastric carcinogenesis, and is accompanied by strongly enhanced gastric mucosal matrix metalloproteinase-9 (MMP-9) levels. AIM: This study was performed to investigate whether H. pylori-affected gastric mucosal MMP-2 and MMP-9 levels are reversible by successful treatment of the infection. PATIENTS AND METHODS: Fifty-eight patients with H. pylori-associated gastritis were treated with a combination regimen of acid inhibitory therapy and antibiotics for 14 days. The levels and isoforms of MMP-2 and MMP-9 were measured by semiquantitative gelatin-zymography, bioactivity assay and enzyme-linked immunosorbent assay in gastric mucosal biopsy homogenates. RESULTS: Latent, active, and total MMP-9 levels decreased consistently and significantly by successful H. pylori eradication, in antrum as well as corpus mucosa, compared with those prior to treatment, irrespective of the therapy regimen used. The elevated levels remained unchanged, however, when treatment failed. MMP-2 levels did not show major alterations after H. pylori therapy. CONCLUSION: Elevated MMP-9 levels in H. pylori-infected gastric mucosa are reversible by eradication of the infection. No major changes in mucosal MMP-2 levels were observed by H. pylori eradication.     

Effect of probiotics and triple eradication therapy on the cyclooxygenase (COX)-2 expression, apoptosis, and functional gastric mucosal impairment in Helicobacter pylori-infected Mongolian gerbils

BACKGROUND: Helicobacter pylori infection in Mongolian gerbils is an established experimental model of gastric carcinogenesis that mimics H. pylori-positive patients developing gastric ulcer and gastric cancer, but the effect of probiotic therapy on functional aspects of this infection remains unknown. METHODS: We compared the effects of intragastric inoculation of gerbils with H. pylori strain (cagA+ vacA+, 5 x 10(6) colony forming units/ml) with or without triple therapy including omeprazole, amoxicillin, and tinidazol or probiotic bacteria Lacidofil. Histology of glandular mucosa, the viable H. pylori, and density of H. pylori colonization were evaluated. The gastric blood flow was measured by H2-gas clearance method; the plasma gastrin and gastric luminal somatostatin were determined by RIA and expression of cyclooxygenase (COX)-2 and apoptotic Bax and Bcl-2 proteins were evaluated by Western blot. RESULTS: The gastric H. pylori infection was detected in all animals by histology and H. pylori culture. Basal gastric acid was significantly reduced in H. pylori-infected animals but not in those with triple therapy or Lacidofil. Early lesions were seen already 4 weeks upon H. pylori inoculation and consisted of chronic gastritis and glandular atypia associated with typical regenerative hyperplasia and increased mitotic activity and formation of apoptotic bodies. The H. pylori infection was accompanied by the fall in gastric blood flow, the marked increase in plasma gastrin, the significant fall in gastric somatostatin levels and Bcl-2 protein expression, and the rise in expression of COX-2 and Bax proteins. These mucosal changes were counteracted by the triple therapy and Lacidofil. CONCLUSIONS: H. pylori infection in gerbils, associated with regenerative hyperplasia of glandular structure, results in the suppression of gastric secretion, overexpression of COX-2, and enhancement in apoptosis and impairment of both, gastric blood flow and gastrin-somatostatin link that were reversed by anti-H. pylori triple therapy and attenuated by probiotics.     

Effect of dietary anti-urease immunoglobulin Y on Helicobacter pylori infection in Mongolian gerbils

BACKGROUND AND AIM: Helicobacter pylori is known to be a major pathogenic factor in the development of gastritis, peptic ulcer disease and gastric cancer. Recently, chicken egg yolk immunoglobulin Y (IgY) has been recognized as an inexpensive antibody source for passive immunization against gastrointestinal infections. The present study was designed to investigate the effect of anti-urease IgY on H. pylori infection in Mongolian gerbils. METHODS: H. pylori-infected Mongolian gerbils were administered a diet containing anti-urease IgY, with or without famotidine (F). After 10 weeks, bacterial culture and measurement of the gastric mucosal myeloperoxidase (MPO) activity were performed. In a second experiment, another group of gerbils was started on a diet containing F + IgY a week prior to H. pylori inoculation. After 9 weeks, these animals were examined. RESULTS: In the H. pylori-infected gerbils, there were no significant differences in the level of H. pylori colonization among the different dietary and control groups. However, the MPO activity was significantly decreased in the H. pylori group administered the F + IgY diet compared with that in the H. pylori group administered the IgY, F, or control diet. Furthermore, in the gerbils administered the F + IgY diet prior to the bacterial inoculation, inhibition of H. pylori colonization and suppression of the elevated gastric mucosal MPO activity were observed. CONCLUSIONS: Oral administration of urease-specific IgY not only inhibited H. pylori disease activity in H. pylori-infected gerbils, but also prevented H. pylori colonization in those not yet infected. These encouraging results may pave the way for a novel therapeutic and prophylactic approach in the management of H. pylori-associated gastroduodenal disease.     

Ammonia-induced apoptosis is accelerated at higher pH in gastric surface mucous cells

Gastric luminal ammonia produced by Helicobacter pylori has been shown to cause gastric mucosal injury. This study was conducted to examine the mechanisms by which gastric luminal ammonia causes apoptosis of gastric epithelial cells. Monolayers of GSM06 cells, developed from murine gastric surface mucous cells, were cultured in the absence or presence of 10-30 mM NH(4)Cl at ambient pH of 5.0, 6.0, and 7.0. In the presence of luminal NH(4)Cl, GSM06 cells showed 1) cell shrinkage and nuclear chromatin condensation, 2) DNA fragmentation into oligonucleosomes, 3) leakage of cytochrome c into cytosolic fraction without affecting bax expression, and 4) increases in activity of caspases-3 and -9. These changes were accentuated when the cells were cultured at pH 7.0. In the absence of NH(4)Cl, none of these changes was detected at any pH examined. These results suggest that gastric luminal ammonia, at concentrations detected in H. pylori-infected subjects, induces apoptosis of gastric epithelial cells by release of cytochrome c from mitochondria, followed by activation of caspases-9 and -3, especially at higher ambient pH.     

Activation of peroxisome proliferator-activated receptor gamma suppresses nuclear factor kappa B-mediated apoptosis induced by Helicobacter pylori in gastric epithelial cells

Helicobacter pylori colonization leads to epithelial cell hyperproliferation within inflamed mucosa, but levels of apoptosis vary, suggesting that imbalances between rates of cell production and loss may contribute to differences in gastric cancer risk among infected populations. Peroxisome proliferator-activated receptor gamma (PPARgamma) regulates inflammatory and growth responses of intestinal epithelial cells. We determined whether activation of PPARgamma modified H. pylori-induced apoptosis in gastric epithelial cells. PPARgamma was expressed and functionally active in gastric epithelial cell lines sensitive to H. pylori-induced apoptosis. PPARgamma ligands 15d-PGJ(2) and BRL-49653 significantly attenuated H. pylomicronri-induced apoptosis, effects that could be reversed by co-treatment with a specific PPARgamma antagonist. Cyclopentanone prostaglandins that do not bind and activate PPARgamma had no effects on H. pylori-induced apoptosis. The ability of H. pylori to activate nuclear factor (NF)-kappaB and increase levels of the NF-kappaB target IL-8 was blocked by co-treatment with PPARgamma agonists, and direct inhibition of NF-kappaB also abolished H. pylori-stimulated apoptosis. These results suggest that activation of the PPARgamma pathway attenuates the ability of H. pylori to induce NF-kappaB-mediated apoptosis in gastric epithelial cells. Because PPARgamma regulates a multitude of host responses, activation of this receptor may contribute to varying levels of cellular turnover as well as the diverse pathologic outcomes associated with chronic H. pylori colonization.     

幽门螺杆菌感染促进胃炎儿童胃粘膜细胞的增殖

本研究旨在探讨幽门螺杆菌感染对小儿慢性胃炎患者细胞增殖的影响,使用内镜检查消化不良患者的上消化道症状,使用改良的Giemsa染色检测胃粘膜活组织中幽门螺杆菌,用苏木精/曙红和改良的吉姆萨染色活组织,并通过光学显微镜研究染色后胃粘膜样品组织病理学变化,RT-PCR检测各组胃粘膜细胞中调控细胞凋亡的Bcl-2、Bcl-xl、Bax和PCNA的mRNA表达,提取胃粘膜细胞蛋白质,利用蛋白质免疫印迹分析蛋白质浓度。组织化学染色结果表明,与对照相比,患有胃炎和幽门杆菌感染后的胃炎患者胃粘膜细胞明显增加,且幽门螺杆菌感染后细胞增殖更显著(p<0.05);幽门螺杆菌感染后Bcl-2和Bcl-xl,PCNA在患者体内表达显著上调(p<0.05),而细胞促凋亡因子Bax基因在胃炎患者感染幽门螺杆菌后被显著下调(p<0.05),蛋白免疫印迹分析Bcl-2,Bcl-xl,Bax和PCNA蛋白表达趋势与基因表达一致,说明结果可靠。幽门螺杆菌感染会显著提高慢性胃炎儿童患者胃粘膜细胞的增殖。     

Presence of Thrombin-Activatable Fibrinolysis Inhibitor in Helicobacter pylori-Associated Gastroduodenal Disease

Thrombin-activatable fibrinolysis inhibitor (TAFI) plays a role in the regulation of coagulation and inflammation. In addition to inhibiting the fibrinolytic system, TAFI may also regulate the bradykinin and complement systems. We hypothesized that TAFI also plays a role in defense mechanisms of the gastric mucosa during Helicobacter pylori infection. This study comprised 65 patients with gastroduodenal disorders: 41 patients with H. pylori infection, 13 without, and 11 patients with cured H. pylori infection. The gastric intramucosal concentrations of TAFI were measured by enzyme immunoassay. The gastric levels of TAFI and plasminogen activator inhibitor-1 were significantly increased in patients with H. pylori compared to those without infection or cured H. pylori . The presence of TAFI was detected in gastric mucosal epithelial cells. The concentration of TAFI was correlated with the degree of gastric mucosal atrophy, inflammation, and disease activity. These results show that TAFI is present in the gastric mucosa and that it may play a role in the pathogenesis of H. pylori infection-associated gastroduodenal disorders.     

Oral vaccination against Helicobacter pylori with recombinant cholera toxin B-subunit

BACKGROUND: The innocuous pure recombinant cholera toxin B-subunit (rCTB) is very attractive as a strong adjuvant for host immunization, but little is known about rCTB's gastric mucosal immunoadjuvanticity against Helicobacter pylori. The immunoadjuvanticity of rCTB against H. pylori was tested. MATERIAL AND METHODS: Mice were immunized with sonicated H. pylori and rCTB orally or intranasally and sacrificed on day 42 after immunization. Passive cutaneous anaphylaxis (PCA) test was performed to evaluate IgE-mediated anaphylaxis with serum from mice to which H. pylori-antigen with rCTB had been administered. Immunoglobulin titer specific to H. pylori in serum, lavation of the gastrointestinal tracts and feces were examined. Gastritis in vaccinated mice after a challenge was assessed with the scoring defined from grading of gastric inflammation. H. pylori proliferation after immunization was investigated by counting colony forming units (CFU) per gram of stomach tissue. RESULTS: PCA test exhibited no reactions against the serum from mice immunized with H. pylori-antigen with rCTB administered orally and intranasally. Oral and nasal coadministrations of rCTB significantly raised systemic and mucosal immunities against H. pylori and suppressed proliferation of H. pylori in gastric mucosa. The score of gastritis in mice immunized orally was significantly higher than that of mice immunized nasally due to postimmunization gastritis. Only oral administration of rCTB suppressed H. pylori proliferation as compared with intranasal administration and without rCTB. CONCLUSIONS: The present study indicated that rCTB has systemic and mucosal immunoadjuvanticities against H. pylori and that oral vaccination with rCTB might additively support antibiotic eradication.     

Role of mast cells as a trigger of inflammation in Helicobacter pylori infection.

Helicobacter pylori (H. pylori) induces severe inflammation and plays a key role in gastric mucosal diseases. In general, mast cells have been believed to play an important role in inflammation. Although mast cells were detected in the gastric mucosa, the role of mast cells in the gastric mucosal inflammation caused by H. pylori is still unclear. Therefore, we examined the effects of H. pylori water extract on the degranulation of mast cells to clarify the role of these cells in gastric mucosal inflammation induced by H. pylori. Mast cells prepared from rat abdominal cavity were incubated with H. pylori for 30 min. The protein concentrations of H. pylori water extract used in this study were 0.5-3 mg/ml. The degranulation of mast cells were monitored morphologically by phase contrast microscopy equipped with time-lapse video recording system and biochemically by measuring histamine and beta-hexosaminidase. H. pylori water extract induced the degranulation of mast cells dose-dependently. The identical experiment was performed without extracellular calcium, and no significant degranulation was found. The data indicates that the degranulation of mast cells by H. pylori water extract depend on extracellular calcium. The present results indicate that H. pylori might be involved in the gastric mucosal inflammation as a trigger of mast cell degranulation for releasing chemical mediators.     

Mucosal immune responses are related to reduction of bacterial colonization in the stomach after therapeutic Helicobacter pylori immunization in mice

The aim of this study was to investigate the capacity of oral and parenteral therapeutic immunization to reduce the bacterial colonization in the stomach after experimental Helicobacter pylori infection, and to evaluate whether any specific immune responses are related to such reduction. C57BL/6 mice were infected with H. pylori and thereafter immunized with H. pylori lysate either orally together with cholera toxin or intraperitoneally (i.p.) together with alum using immunization protocols that previously have provided prophylactic protection. The effect of the immunizations on H. pylori infection was determined by quantitative culture of H. pylori from the mouse stomach. Mucosal and systemic antibody responses were analyzed by ELISA in saponin extracted gastric tissue and serum, respectively, and mucosal CD4+ T cell responses by an antigen specific proliferation assay. Supernatants from the proliferating CD4+ T cells were analyzed for Th1 and Th2 cytokines. The oral, but not the parenteral therapeutic immunization induced significant decrease in H. pylori colonization compared to control infected mice. The oral immunization resulted in markedly elevated levels of serum IgG+M as well as gastric IgA antibodies against H. pylori antigen and also increased H. pylori specific mucosal CD4+ T cell proliferation with a Th1 cytokine profile. Although the parenteral immunization induced dramatic increases in H. pylori specific serum antibody titers, no increases in mucosal antibody or cellular immune responses were observed after the i.p. immunization compared to control infected mice. These findings suggest that H. pylori specific mucosal immune responses with a Th1 profile may provide therapeutic protection against H. pylori.     

Docosahexaenoic acid inhibits Helicobacter pylori growth in vitro and mice gastric mucosa colonization

H. pylori drug-resistant strains and non-compliance to therapy are the major causes of H. pylori eradication failure. For some bacterial species it has been demonstrated that fatty acids have a growth inhibitory effect. Our main aim was to assess the ability of docosahexaenoic acid (DHA) to inhibit H. pylori growth both in vitro and in a mouse model. The effectiveness of standard therapy (ST) in combination with DHA on H. pylori eradication and recurrence prevention success was also investigated. The effects of DHA on H. pylori growth were analyzed in an in vitro dose-response study and n in vivo model. We analized the ability of H. pylori to colonize mice gastric mucosa following DHA, ST or a combination of both treatments. Our data demonstrate that DHA decreases H. pylori growth in vitro in a dose-dependent manner. Furthermore, DHA inhibits H. pylori gastric colonization in vivo as well as decreases mouse gastric mucosa inflammation. Addition of DHA to ST was also associated with lower H. pylori infection recurrence in the mouse model. In conclusion, DHA is an inhibitor of H. pylori growth and its ability to colonize mouse stomach. DHA treatment is also associated with a lower recurrence of H. pylori infection in combination with ST. These observations pave the way to consider DHA as an adjunct agent in H. pylori eradication treatment.     

Helicobacter pylori lipopolysaccharide effect on the synthesis and secretion of gastric sulfomucin.

The effect of H. pylori lipopolysaccharide on the synthesis and secretion of sulfated mucin in gastric mucosa was investigated using mucosal segments incubated in the presence of [3H]proline, [3H]glucosamine and [35S]Na2SO4. The lipopolysaccharide, while showing no discernible effect on the apomucin synthesis was found to inhibit the process of mucin glycosylation and sulfation, which at 100 micrograms/ml lipopolysaccharide reached the optimal inhibition of 65%. The analysis of mucin secretory responses revealed that the lipopolysaccharide by first 15 min caused a 57% stimulation in sulfomucin secretion followed thereafter by inhibition, which reached maximum of 32% by 45 min. The results suggest that colonization of gastric mucosa by H. pylori may be detrimental to the process of gastric sulfomucin synthesis and secretion.