- Email: [email protected]
The effects of Helicobacter pylori infection on the signal transduction of gastric epithelial cells
W890
the EGT values before and 2-3 months after the therapy were also studied. The degrees of inflammation, activity, and atrophy were scored (0-3) according to the updated Sydney system. RESULTS: The EGT value was higher in patients with Hp infection (mean, SD: 4.20, 2.67 mEq/10 rain) than in those without the infection (2.67, 0.95 mEq/lO rain) (p<0,05): in Hp-infected patients, the EGT value of patients with duodenal ulcer (n = 5) (6.56, 3.03 mEq/10 rain) was higher than that of patients with gastritis alone (n = 10) (3.01, 1.52 mEq/ 10 rain) (p<0.01). There was no difference in the EGT value before (5.22, 2.53 mEq/10 min) and after eradication therapy (4.60, 2.50 mEq/10 rain) (p = 0.30). Histological study demonstrated that Hp infection significantly increased the degrees of inflammation and activity of gastritis in both gastric antrum and body. Among all patients studied, the EGT value correlated with the degree of inthmmation of gastric body (r= 0.35, p<0.05) but not with that of gastric antrum (r = 0.28, p = O.13). There was no significant correlation between the EGT value and the degree of activity. CONCLUSIONS: Hp infection increases gastric acid secretion in children, which is associated with infiltration of mononuclear ceils in the gastric body. Gastric hypersecretion is important in the pathogenesis of childhood duodenal ulcer..
Helicobacter Pylori Infection Induces the Loss of Sonic Hedgehog and Patched Expression R~kako Oshima, Michiko [wamnto, Hiroypki Osawa, Yoshinari Kaneko, Hiroyuki Muto, Kiichi Sato, Kentaro Sugano BKG: Hehcobacter pylori intection is caused of the atrophic gastritis, intestinal metaplasia, gastric dysplasia and gastric careinomas. Recent studies in the gastric carcinogenesis suggest sonic hedgehog (Shh) and patched (Ptc) which is the receptor of Shh are important regulator of gastric epithelial cell proliferation. AIM: 1o determine whether the Shh or Ptc is present in the atrophic gastritis, intestinal metaplasia, gastric dysplasia and gastric carcinomas with helicobacter pylori infection or in the inflammatory mucosa without helicobacter pylori infection. MATHER1ALS & METHODS: Eighty patients with helicobacter pylori infection and the atrophic gastritis, intestinal metaplasta, gastric dysplasia, gastric carcinomas and without helicobacter pylori infection and with normal mucosa were identified for Shh and Pte expression through Jichi Medical School between 1997 and 2002. Shh and Ptc protein expression were assessed nsmg double staining of immunohistochemistry. Shh and Ptc mRNA expression were qnantitated using TaqMan PCR methods with mRNA-specific primers. RESULTS: Shh immunoreactivity was present in all the cytoplasm of the normal parietal cells, whereas Ptc in~munoreactivity was present in other gland cells in addition to parietal cells. Parietal cells were decreased in the atrophic gastritis and metaplasia. Percentage of Shh and t~c positive ceils vras decreased in 30% according to the decrease of the parietal cells There were no parietal cells in the gastric dysplasia and carcinoma. No Shh and Ptc immunoreactivity was present in the gastric dyspfasia and carcinomas, whereas Shh and Ptc immunoreactivity in the inflamm~toty mucosa without helicobacter pylori infection were present in the parietal cells. CONCLUSION: Decrease and loss of Shh and Ptc expression occur in accordance to the decrease of parietal cells. These results suggest helicobacter pylori intection may result in the decrease of Shh and Ptc expression and the number of the parietal cells. Loss of Shh and Ptc expression may lose tbe regulation of the proliferation of the epithelial cells.
W893
The Effects of Helicobacter pylon Infection on The Signal Transduction of Gastric Epithelial Cells Takeshi Azuma, Shiho Yamazaki, Akiyo Yamakawa, Masahiro Ohtam, Yoshiyuki Ito, Manabu Dojo, Yukinao Yamazaki Background and Aim: Recent experiments have indicated that CagA of H, pylori is injected into epithelial cells via the type IV secretion system and undergoes tyrosine phosphorylation in the cells, and that translocated CagA binds the SRC homology 2 domain-containing tyrosine phosphatase (SHP-2). We investigated these phenomena in in vivo human gastric mucosa. We also examined the eftect of eradication therapy on the signal transduction pathway of gastric epithelial cells induced by the CagA protein ofH. pylori. Methods: Twenty patients with atrophic gastritis, 5 patients with early gastric cancer, and 5 H. D, lori-nagative normal controls participated in the present study. The biopsy specimens were subjected to culture of H. p)'lori and to immunoblot analysis to detect tyrosine phosphorylated CagA protein and CagA co-immunoprecipitated endogenous SHP-2. H, pylori-positive patients underwent the eradication therapy for H. pylori infection. Gastric biopsy specimens were also obtained 3 months after the eradication therapy, and subjected to the immunoblot analysis. Results: All patients in the present study' were H. pylori-positive. All H. pylori strains from these patients were cagA-positive type 1 strains. The tyrosine pbosphorylated CagA and CagA co-immunoprecipitated SHP-2 were detected in the gastric mucosa trom H. D,loripositive atrophic gastritis patients and in non-cancer tissues from H. pylor/-positive early gastric cancer patients. In contrast, CagA was not detected in the gastric mucosa with intestinal metaplasia or cancer. After curing R pylori infection, the tyrosine phnsphorylated CagA protein and CagA co-immunoprecipitated endogenous SHP-2 disappeared from the gastric mucosa. Conclusion: CagA is translocated into the gastric epithelial cells, receives tyrosine phosphorylation, and binds SHP-2 in in vivo human gastric mucosa, Deregulation of SHP-2 by CagA may play a role in the acquisition of a cellular transformed phenotype at a relatively early stage of multistep gastric carcinogenesis. The cure of infection reduces the stimulated signal transduction of gastric epithelial cells by the translocated CagA protein of H. pylori, and may confer a beneficial effect on the reduction of cancer risk.
W891
Reduced Ability to Maintain a Neutral Gastric Juxtamucosal pH in Mice Infected with Helicobacter pylori Johanna Hem'iksnas, 1.ars gngstrand, Lena Holm Introduction: We have previonsly shown that a pH gradient, with a neutral pH at the surface epithelial cells, is maintained in the mucus covering the corpus mucosa in rats when challenged with luminal HC1. Earlier studies have also shown that gastric mucus can be divided in two adherent layers. One layer possible to remove and another fimly adherent. The loosely adherent mucus layer is less important in maintaining the juxtamucosal pH (in the precence of luminal acid pH 1). Furthermore, mice chronically infected with Helicobacter pylor~ have a thinner firmly adherent mucus layer than non-nifected control mice. We therefore wanted to investigate if mice intected with H. priori maintain the neutral pH when challenged with HCL Methods: FVtVN mice expressing the human e~-l,3/4-fucosyhransfarase (which will produce L@ epitopes), were inoculated with H. D, lor/ 1 (107 CFU/mouse) tollowed by a stabilizing period of at least 11 weeks. The mice were anaesthetized with Hypnorm and Mid_azolam. 1he stomach was exteriorized and the mucosal surface of the corpus visualized. Juxtamucosal pH was measured with pN sensitive microelectrodes, connected to a micromanipulator and positioned just above the epithelial cells, pH was measured before, during and after luminal instillation of HCI pH 2 and 1.5. Results: The juxtamucosal pH decreased significantly more in H. pylori infected animals during instillation of HCI pH 2 and L5 than in non-infected animals. The results are presented in the table below. Conclusion: H. pylori infection reduces the ability to maintain the juxtamucosal pH neutral in the presence of luminal acid. This could he due to the thinner inner mucus layer we have found earlier in H. pylori intected mice.
W894
Helicobacter pylori Water Extract Induces Nuclear Factor-kappa B, Activator Protein-1 and Cyclooxygenase-2 in Oesophageal Epithelial Cells: Evidence for role of p38, ERK and JNK phosphorylation
Mohamed M, M. Abdel-Latif, Henry J. Windle, Aria M, Terres, Dermot Kefleber, john V, Reynolds
Juxtamucosal pH Saline
HCI pH 2 Saline HCl pH 1.5
Control
n
7.2+/-0,2 6.9+k0.3 71 +/-0,2 6,1+/-0,5"
6 6 6 4
Infected
n
6.7+/-0.6
5
4.6+/-0,8*~
5
6.6+/-0,8 2,4+/-fl,7~
5 5
Background and Aims: The specific immune response in the oesophagus may be critical in determining whether an individual is at risk of developing gastroesophageal reflux, and Barrett's adenocareinoma carcinoma. The aim of this study was to examine the ettect of H. pylori on the expression of NF-KB, AP-I and COX-2 in the oesophageal epithelial cell lines SKGT-4 and OE33, Methods: SKGT-4 and OE33 cells were cocufiured with i ml of Live H. priori or 1 ml of H. pylori water extract ( H P ~ ) for 1 h, The ratio of Lree H. pylori to oesophageal cells was adjusted to 100:1. NF-KB and AP-1 activity were assessed by gel shift assay, while COX-2 by Western blotting. Results: Coculture of SKGT-4 and OE33 with Live H pylori and HPWE reduced NF-KB and AP-I DNA-binding activity. Live H. priori or HPWE also prevented IkB:a degradation Vitamin C inhibited H. priori-induced NF-kB activation but rather increased AP- 1 expression. Moreover, HPWE induced COX-2 expression and specific COX-2 inhibitor (NS-398) reduced H. pylori-induced NF-KB and COX-2 activation but not AP-1, The activation of NF-KB, AP-1 is mediated via phosphorylation of p38, ERK and JNK signalling pathway. Conclusions: The induction of transcription factors like NF-KB, AP-1 and COX-2 by H. D, lori may pLay a role in the specific immune response within Barrett's mucosa. H. priori may indirectly cause chronic inflammation of the gastric cardia and the distal oesophagus.
Saline 7,04-0.04 4 4,8+/-0,3~ 5 The values are mean of 5rain +/-SEM, n=numberof mice, *p
control group
W892 The Influence of Helicobacter pylori Infection on Gastric Acid Secretion in Children seiichi Kato, Kyoko Ozawa, Tomoyuki Koike, Hitoshi Sekine, Shnichi Ohara, Kazuie Iinuma BACKGROUND: Helicobacter pylori(Hp) infection is associated with gastritis and duodenal ulcer in childhood. However, there are few studies concerning the influence of Hp infection on gastric acid secretion in children. The purpose of this study was to investigate gastric acid secretion in pediatric patients with or witbout the infection METHODS: A total of 32 patients (male, 19) aged 10-17 years who underwent upper GI endoscopy and biopsy (gastric antrum and body) tbr G1 symptoms were studied. Diagnoses included gastritis (n = 20), duodenal ulcer (n = 5), and normal histology without ulcers (n = 7). Biopsy tests and ~Curea breath test confirmed that 15 patients (mean, SD: 13.5, 2.1 years) were infected with Hp and 17 patients (12.8, 2.3 )'ears) were not infected (p=0.35): there was no difference in the male:temale ratio between both groups (p = 0.13) Gastric acid secretion was studied using the endoscopic gastrin test (EGT) (Am j Gastroenterol 1998;93:2113): gastric fluid was collected between 20 and 30 rain after injection of pentagastrin (6 p.g/kg) and acid output was expressed as the EGT value (H ~ mEq/l 0 rain). In 10 patients with Hp eradication,
w895 Hyperhomocysteinemia, Helicobacter Pylori And Atrophic Gastritis Maurizio Gabriefli, Luca Santarelli, Filippo Cremomm, Ascanio Tridente, Barbara De Pascalis, Paolo Pofa, Giovanni Gasbarrini, Antonio Gasbarrini, Veronica Ojetti Background and aim: Hyperhomocysteinemia is a risk factor for thrombotic diseases, often caused by deficency of vitamin B12 and folic acid, cofactors in methionine metabolic pathway. Since vitamin B12 absorption depends on the secretion of intrinsic factor by' the gastric parietal cells, atrophic gastritis may cause vitaminic malabsorption. Aim of the study was to assess the role of gastric atrophy induced by H.pylori in the determinism of hyperhomocTsteinemia. Material and Methods: We recruited 46 dyspeptic patients (27 women, mean age
A-589
AGA
Abstracts
the EGT values before and 2-3 months after the therapy were also studied. The degrees of inflammation, activity, and atrophy were scored (0-3) according to the updated Sydney system. RESULTS: The EGT value was higher in patients with Hp infection (mean, SD: 4.20, 2.67 mEq/10 rain) than in those without the infection (2.67, 0.95 mEq/lO rain) (p<0,05): in Hp-infected patients, the EGT value of patients with duodenal ulcer (n = 5) (6.56, 3.03 mEq/10 rain) was higher than that of patients with gastritis alone (n = 10) (3.01, 1.52 mEq/ 10 rain) (p<0.01). There was no difference in the EGT value before (5.22, 2.53 mEq/10 min) and after eradication therapy (4.60, 2.50 mEq/10 rain) (p = 0.30). Histological study demonstrated that Hp infection significantly increased the degrees of inflammation and activity of gastritis in both gastric antrum and body. Among all patients studied, the EGT value correlated with the degree of inthmmation of gastric body (r= 0.35, p<0.05) but not with that of gastric antrum (r = 0.28, p = O.13). There was no significant correlation between the EGT value and the degree of activity. CONCLUSIONS: Hp infection increases gastric acid secretion in children, which is associated with infiltration of mononuclear ceils in the gastric body. Gastric hypersecretion is important in the pathogenesis of childhood duodenal ulcer..
Helicobacter Pylori Infection Induces the Loss of Sonic Hedgehog and Patched Expression R~kako Oshima, Michiko [wamnto, Hiroypki Osawa, Yoshinari Kaneko, Hiroyuki Muto, Kiichi Sato, Kentaro Sugano BKG: Hehcobacter pylori intection is caused of the atrophic gastritis, intestinal metaplasia, gastric dysplasia and gastric careinomas. Recent studies in the gastric carcinogenesis suggest sonic hedgehog (Shh) and patched (Ptc) which is the receptor of Shh are important regulator of gastric epithelial cell proliferation. AIM: 1o determine whether the Shh or Ptc is present in the atrophic gastritis, intestinal metaplasia, gastric dysplasia and gastric carcinomas with helicobacter pylori infection or in the inflammatory mucosa without helicobacter pylori infection. MATHER1ALS & METHODS: Eighty patients with helicobacter pylori infection and the atrophic gastritis, intestinal metaplasta, gastric dysplasia, gastric carcinomas and without helicobacter pylori infection and with normal mucosa were identified for Shh and Pte expression through Jichi Medical School between 1997 and 2002. Shh and Ptc protein expression were assessed nsmg double staining of immunohistochemistry. Shh and Ptc mRNA expression were qnantitated using TaqMan PCR methods with mRNA-specific primers. RESULTS: Shh immunoreactivity was present in all the cytoplasm of the normal parietal cells, whereas Ptc in~munoreactivity was present in other gland cells in addition to parietal cells. Parietal cells were decreased in the atrophic gastritis and metaplasia. Percentage of Shh and t~c positive ceils vras decreased in 30% according to the decrease of the parietal cells There were no parietal cells in the gastric dysplasia and carcinoma. No Shh and Ptc immunoreactivity was present in the gastric dyspfasia and carcinomas, whereas Shh and Ptc immunoreactivity in the inflamm~toty mucosa without helicobacter pylori infection were present in the parietal cells. CONCLUSION: Decrease and loss of Shh and Ptc expression occur in accordance to the decrease of parietal cells. These results suggest helicobacter pylori intection may result in the decrease of Shh and Ptc expression and the number of the parietal cells. Loss of Shh and Ptc expression may lose tbe regulation of the proliferation of the epithelial cells.
W893
The Effects of Helicobacter pylon Infection on The Signal Transduction of Gastric Epithelial Cells Takeshi Azuma, Shiho Yamazaki, Akiyo Yamakawa, Masahiro Ohtam, Yoshiyuki Ito, Manabu Dojo, Yukinao Yamazaki Background and Aim: Recent experiments have indicated that CagA of H, pylori is injected into epithelial cells via the type IV secretion system and undergoes tyrosine phosphorylation in the cells, and that translocated CagA binds the SRC homology 2 domain-containing tyrosine phosphatase (SHP-2). We investigated these phenomena in in vivo human gastric mucosa. We also examined the eftect of eradication therapy on the signal transduction pathway of gastric epithelial cells induced by the CagA protein ofH. pylori. Methods: Twenty patients with atrophic gastritis, 5 patients with early gastric cancer, and 5 H. D, lori-nagative normal controls participated in the present study. The biopsy specimens were subjected to culture of H. p)'lori and to immunoblot analysis to detect tyrosine phosphorylated CagA protein and CagA co-immunoprecipitated endogenous SHP-2. H, pylori-positive patients underwent the eradication therapy for H. pylori infection. Gastric biopsy specimens were also obtained 3 months after the eradication therapy, and subjected to the immunoblot analysis. Results: All patients in the present study' were H. pylori-positive. All H. pylori strains from these patients were cagA-positive type 1 strains. The tyrosine pbosphorylated CagA and CagA co-immunoprecipitated SHP-2 were detected in the gastric mucosa trom H. D,loripositive atrophic gastritis patients and in non-cancer tissues from H. pylor/-positive early gastric cancer patients. In contrast, CagA was not detected in the gastric mucosa with intestinal metaplasia or cancer. After curing R pylori infection, the tyrosine phnsphorylated CagA protein and CagA co-immunoprecipitated endogenous SHP-2 disappeared from the gastric mucosa. Conclusion: CagA is translocated into the gastric epithelial cells, receives tyrosine phosphorylation, and binds SHP-2 in in vivo human gastric mucosa, Deregulation of SHP-2 by CagA may play a role in the acquisition of a cellular transformed phenotype at a relatively early stage of multistep gastric carcinogenesis. The cure of infection reduces the stimulated signal transduction of gastric epithelial cells by the translocated CagA protein of H. pylori, and may confer a beneficial effect on the reduction of cancer risk.
W891
Reduced Ability to Maintain a Neutral Gastric Juxtamucosal pH in Mice Infected with Helicobacter pylori Johanna Hem'iksnas, 1.ars gngstrand, Lena Holm Introduction: We have previonsly shown that a pH gradient, with a neutral pH at the surface epithelial cells, is maintained in the mucus covering the corpus mucosa in rats when challenged with luminal HC1. Earlier studies have also shown that gastric mucus can be divided in two adherent layers. One layer possible to remove and another fimly adherent. The loosely adherent mucus layer is less important in maintaining the juxtamucosal pH (in the precence of luminal acid pH 1). Furthermore, mice chronically infected with Helicobacter pylor~ have a thinner firmly adherent mucus layer than non-nifected control mice. We therefore wanted to investigate if mice intected with H. priori maintain the neutral pH when challenged with HCL Methods: FVtVN mice expressing the human e~-l,3/4-fucosyhransfarase (which will produce L@ epitopes), were inoculated with H. D, lor/ 1 (107 CFU/mouse) tollowed by a stabilizing period of at least 11 weeks. The mice were anaesthetized with Hypnorm and Mid_azolam. 1he stomach was exteriorized and the mucosal surface of the corpus visualized. Juxtamucosal pH was measured with pN sensitive microelectrodes, connected to a micromanipulator and positioned just above the epithelial cells, pH was measured before, during and after luminal instillation of HCI pH 2 and 1.5. Results: The juxtamucosal pH decreased significantly more in H. pylori infected animals during instillation of HCI pH 2 and L5 than in non-infected animals. The results are presented in the table below. Conclusion: H. pylori infection reduces the ability to maintain the juxtamucosal pH neutral in the presence of luminal acid. This could he due to the thinner inner mucus layer we have found earlier in H. pylori intected mice.
W894
Helicobacter pylori Water Extract Induces Nuclear Factor-kappa B, Activator Protein-1 and Cyclooxygenase-2 in Oesophageal Epithelial Cells: Evidence for role of p38, ERK and JNK phosphorylation
Mohamed M, M. Abdel-Latif, Henry J. Windle, Aria M, Terres, Dermot Kefleber, john V, Reynolds
Juxtamucosal pH Saline
HCI pH 2 Saline HCl pH 1.5
Control
n
7.2+/-0,2 6.9+k0.3 71 +/-0,2 6,1+/-0,5"
6 6 6 4
Infected
n
6.7+/-0.6
5
4.6+/-0,8*~
5
6.6+/-0,8 2,4+/-fl,7~
5 5
Background and Aims: The specific immune response in the oesophagus may be critical in determining whether an individual is at risk of developing gastroesophageal reflux, and Barrett's adenocareinoma carcinoma. The aim of this study was to examine the ettect of H. pylori on the expression of NF-KB, AP-I and COX-2 in the oesophageal epithelial cell lines SKGT-4 and OE33, Methods: SKGT-4 and OE33 cells were cocufiured with i ml of Live H. priori or 1 ml of H. pylori water extract ( H P ~ ) for 1 h, The ratio of Lree H. pylori to oesophageal cells was adjusted to 100:1. NF-KB and AP-1 activity were assessed by gel shift assay, while COX-2 by Western blotting. Results: Coculture of SKGT-4 and OE33 with Live H pylori and HPWE reduced NF-KB and AP-I DNA-binding activity. Live H. priori or HPWE also prevented IkB:a degradation Vitamin C inhibited H. priori-induced NF-kB activation but rather increased AP- 1 expression. Moreover, HPWE induced COX-2 expression and specific COX-2 inhibitor (NS-398) reduced H. pylori-induced NF-KB and COX-2 activation but not AP-1, The activation of NF-KB, AP-1 is mediated via phosphorylation of p38, ERK and JNK signalling pathway. Conclusions: The induction of transcription factors like NF-KB, AP-1 and COX-2 by H. D, lori may pLay a role in the specific immune response within Barrett's mucosa. H. priori may indirectly cause chronic inflammation of the gastric cardia and the distal oesophagus.
Saline 7,04-0.04 4 4,8+/-0,3~ 5 The values are mean of 5rain +/-SEM, n=numberof mice, *p
control group
W892 The Influence of Helicobacter pylori Infection on Gastric Acid Secretion in Children seiichi Kato, Kyoko Ozawa, Tomoyuki Koike, Hitoshi Sekine, Shnichi Ohara, Kazuie Iinuma BACKGROUND: Helicobacter pylori(Hp) infection is associated with gastritis and duodenal ulcer in childhood. However, there are few studies concerning the influence of Hp infection on gastric acid secretion in children. The purpose of this study was to investigate gastric acid secretion in pediatric patients with or witbout the infection METHODS: A total of 32 patients (male, 19) aged 10-17 years who underwent upper GI endoscopy and biopsy (gastric antrum and body) tbr G1 symptoms were studied. Diagnoses included gastritis (n = 20), duodenal ulcer (n = 5), and normal histology without ulcers (n = 7). Biopsy tests and ~Curea breath test confirmed that 15 patients (mean, SD: 13.5, 2.1 years) were infected with Hp and 17 patients (12.8, 2.3 )'ears) were not infected (p=0.35): there was no difference in the male:temale ratio between both groups (p = 0.13) Gastric acid secretion was studied using the endoscopic gastrin test (EGT) (Am j Gastroenterol 1998;93:2113): gastric fluid was collected between 20 and 30 rain after injection of pentagastrin (6 p.g/kg) and acid output was expressed as the EGT value (H ~ mEq/l 0 rain). In 10 patients with Hp eradication,
w895 Hyperhomocysteinemia, Helicobacter Pylori And Atrophic Gastritis Maurizio Gabriefli, Luca Santarelli, Filippo Cremomm, Ascanio Tridente, Barbara De Pascalis, Paolo Pofa, Giovanni Gasbarrini, Antonio Gasbarrini, Veronica Ojetti Background and aim: Hyperhomocysteinemia is a risk factor for thrombotic diseases, often caused by deficency of vitamin B12 and folic acid, cofactors in methionine metabolic pathway. Since vitamin B12 absorption depends on the secretion of intrinsic factor by' the gastric parietal cells, atrophic gastritis may cause vitaminic malabsorption. Aim of the study was to assess the role of gastric atrophy induced by H.pylori in the determinism of hyperhomocTsteinemia. Material and Methods: We recruited 46 dyspeptic patients (27 women, mean age
A-589
AGA
Abstracts