Effect of acacetin on inhibition of apoptosis in Helicobacter pyloriinfected gastric epithelial cell line

BACKGROUND Helicobacter pylori(H.pylori)infection can cause extensive apoptosis of gastric epithelial cells,serving as a critical catalyst in the progression from chronic gastritis,gastrointestinal metaplasia,and atypical gastric hyperplasia to gastric carcinoma.Prompt eradication of H.pylori is paramount for ameliorating the pathophysiological conditions associated with chronic inflammation of the gastric mucosa and the primary prevention of gastric cancer.Acacetin,which has multifaceted pharmacological activities such as anti-cancer,anti-inflammatory,and antioxidative properties,has been extensively investigated across various domains.Nevertheless,the impact and underlying mechanisms of action of acacetin on H.pylori-infected gastric mucosal epithelial cells remain unclear.AIM To explore the defensive effects of acacetin on apoptosis in H.pylori-infected GES-1 cells and to investigate the underlying mechanisms.METHODS GES-1 cells were treated with H.pylori and acacetin in vitro.Cell viability was assessed using the CCK-8 assay,cell mortality rate via lactate dehydrogenase assay,alterations in cell migration and healing capacities through the wound healing assay,rates of apoptosis via flow cytometry and TUNEL staining,and expression levels of apoptosis-associated proteins through western blot analysis.RESULTS H.pylori infection led to decreased GES-1 cell viability,increased cell mortality,suppressed cell migration,increased rate of apoptosis,increased expressions of Bax and cle-caspase3,and decreased Bcl-2 expression.Conversely,acacetin treatment enhanced cell viability,mitigated apoptosis induced by H.pylori infection,and modulated the expression of apoptosis-regulatory proteins by upregulating Bcl-2 and downregulating Bax and cleaved caspase-3.CONCLUSION Acacetin significantly improved GES-1 cell viability and inhibited apoptosis in H.pylori-infected GES-1 cells,thereby exerting a protective effect on gastric mucosal epithelial cells.

Effect of Helicobacter pylori on gastric epithelial cells

The gastrointestinal epithelium has cells with features that make them a powerful line of defense in innate mucosal immunity. Features that allow gastrointestinal epithelial cells to contribute in innate defense include cell barrier integrity, cell turnover, autophagy, and innate immune responses. Helicobacter pylori (H. pylori) is a spiral shape gram negative bacterium that selectively colonizes the gastric epithelium of more than half of the world’s population. The infection invariably becomes persistent due to highly specialized mechanisms that facilitate H. pylori’s avoidance of this initial line of host defense as well as adaptive immune mechanisms. The host response is thus unsuccessful in clearing the infection and as a result becomes established as a persistent infection promoting chronic inflammation. In some individuals the associated inflammation contributes to ulcerogenesis or neoplasia. H. pylori has an array of different strategies to interact intimately with epithelial cells and manipulate their cellular processes and functions. Among the multiple aspects that H. pylori affects in gastric epithelial cells are their distribution of epithelial junctions, DNA damage, apoptosis, proliferation, stimulation of cytokine production, and cell transformation. Some of these processes are initiated as a result of the activation of signaling mechanisms activated on binding of H. pylori to cell surface receptors or via soluble virulence factors that gain access to the epithelium. The multiple responses by the epithelium to the infection contribute to pathogenesis associated with H. pylori.

Quercetin exerts anti-inflammatory effects via inhibiting tumor necrosis factor-α-induced matrix metalloproteinase-9 expression in normal human gastric epithelial cells

BACKGROUND Gastric injury is the most common digestive system disease worldwide and involves inflammation,which can lead to gastric ulcer or gastric cancer(GC).Matrix metallopeptidase-9[MMP-9(gelatinase-B)]plays an important role in inflammation and GC progression.Quercetin and quercetin-rich diets represent potential food supplements and a source of medications for treating gastric injury given their anti-inflammatory activities.However,the effects and mechanisms of action of quercetin on human chronic gastritis and whether quercetin can relieve symptoms remain unclear.AIM To assess whether tumor necrosis factor-α(TNF-α)-induced MMP-9 expression mediates the anti-inflammatory effects of quercetin in normal human gastric mucosal epithelial cells.METHODS The normal human gastric mucosa epithelial cell line GES-1 was used to establish a normal human gastric epithelial cell model of TNF-α-induced MMP-9 protein overexpression to evaluate the antiinflammatory effects of quercetin.The cell counting Kit-8 assay was used to evaluate the effects of varying quercetin doses on cell viability in the normal GES-1 cell line.Cell migration was measured using Transwell assay.The expression of proto-oncogene tyrosine-protein kinase Src(cSrc),phospho(p)-c-Src,extracellular-signal-regulated kinase 2(ERK2),p-ERK1/2,c-Fos,p-c-Fos,nuclear factor kappa B(NF-κB/p65),and p-p65 and the effects of their inhibitors were examined using Western blot analysis and measurement of luciferase activity.p65 expression was detected by immunofluorescence.MMP-9 m RNA and protein levels were measured by quantitative reverse transcription polymerase chain reaction(q RT–PCR)and gelatin zymography,respectively.RESULTS q RT-PCR and gelatin zymography showed that TNF-αinduced MMP-9 m RNA and protein expression in a dose-and time-dependent manner.These effects were reduced by the pretreatment of GES-1 cells with quercetin or a TNF-αantagonist(TNFR inhibitor)in a dose-and timedependent manner.Quercetin and TNF-αantagonists decreased the TNF-α-induced phosphorylation of c-Src,ERK1/2,c-Fos,and p65 in a dose-and time-dependent manner.Quercetin,TNF-αantagonist,PP1,U0126,and tanshinone IIA(TSIIA)reduced TNF-α-induced c-Fos phosphorylation and AP-1–Luciferase(Luc)activity in a dose-and time-dependent manner.Pretreatment with quercetin,TNF-αantagonist,PP1,U0126,or Bay 11-7082 reduced TNF-α-induced p65 phosphorylation and translocation and p65–Luc activity in a dose-and timedependent manner.TNF-αsignificantly increased GES-1 cell migration,and these results were reduced by pretreatment with quercetin or a TNF-αantagonist.CONCLUSION Quercetin significantly downregulates TNF-α-induced MMP-9 expression in GES-1 cells via the TNFR-c-Src–ERK1/2 and c-Fos or NF-κB pathways.

Effects of H pylori infection on gap-junctional intercellular communication and proliferation of gastric epithelial cells in vitro

AIM： To explore the effects of H pylori infection on gap-junctional intercellular communication （GJIC） and proliferation of gastric epithelial cells in vitro. METHODS： A human gastric epithelial cell line （SGC- 7901） cultured on coverslips was exposed overnight to intact H pylori （CagA^＋ or CagA^- strains） and sonicated extracts, respectively. GJIC between the cells was detected by fluorescence redistribution after photobleaching （FRAP） technique. Proliferation of SGC cells was determined by methylthiazolyl tetrazolium （MTT） assay. RESULTS： When compared with control in which cells were cultured with simple medium alone, both CagA^＋ and CagA^- H pylori isolates could inhibit GJIC （CagA^＋： F = 57.98, P 〈 0.01; CagA^-： F = 29.59, P 〈 0.01） and proliferation （CagA^＋： F = 42.65, P 〈 0.01; CagA^-： F = 58.14, P 〈 0.01） of SGC-7901 cells. Compared with CagA^- strains, CagA^＋ H pylori more significantly downregulated GJIC of gastric cells （intact Hpylori： t = 13.86, P 〈 0.01; sonicated extracts： t = 11.87, P 〈 0.01） and inhibited proliferation gastric cells to a lesser extent in vitro （intact H pylori： t = 3.06, P 〈 0.05; sonicated extracts： t = 3.94, P 〈 0.01）. CONCLUSION： Compared with CagA^- H pylori strains, CagA^＋ strains down-regulate GJIC of gastric epithelial cells more significantly and inhibit proliferation of gastric cells to a lesser extent in vitro. H pylori, especially CagA^＋ strains, may play an important role in gastric carcinogenesis.

Effects of different Helicobacter pylori culture filtrates on growth of gastric epithelial cells

AIM:To study the effects of different Helicobacter pylori(H pylori) culture filtrates on growth of gastric epithelial cells. METHODS:Broth culture filtrates of H pylori were prepared. Gastric epithelial cells were treated with the filtrates,and cell growth was determined by growth curve and flow cytometry. DNA damage of gastric epithelial cells was measured by single-cell microgel electrophoresis. RESULTS:Gastric epithelial cells proliferated actively when treated by CagA-gene-positive broth culture filtrates,and colony formation reached 40%. The number of cells in S phase increased compared to controls. Comet assay showed 41.2% comet cells in GES-1 cells treated with CagA-positive filtrates(P < 0.05) . CONCLUSION:CagA-positive filtrates enhance the changes in morphology and growth characteristics of human gastric epithelial tumor cells. DNA damage maybe one of the mechanisms involved in the growth changes.

Protection of ghrelin postconditioning on hypoxia/ reoxygenation in gastric epithelial cells

AIM: To investigate the protective effect and mechanisms of ghrelin postconditioning against hypoxia/reoxygenation (H/R)-induced injury in human gastric epithelial cells. METHODS: The model of H/R injury was established in gastric epithelial cell line (GES-1) human gastric epithelial cells. Cells were divided into seven groups: normal control group (N); H/R postconditioning group; DMSO postconditioning group (DM); ghrelin postconditioning group (GH); D-Lys3-GHRP-6 + ghrelin postconditioning group (D + GH); capsazepine + ghrelin postconditioning group (C + GH); and LY294002 + ghrelin postconditioning group (L + GH). 3-(4,5-dimethylthazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay was used to detect GES-1 cell viability. Hoechst 33258 fluorochrome staining and flow cytometry were conducted to determine apoptosis of GES-1cells. Spectrophotometry was performed to determine release of lactate dehydrogenate (LDH). Protein expression of Bcl-2, Bax, Akt, and glycogen synthase kinase (GSK)-3β was determined by western blotting. Expression of vanilloid receptor subtype 1 (VR1), Akt and GSK-3β was observed by immunocytochemistry. RESULTS: Compared with the H/R group, cell viability of the GH group was significantly increased in a dosedependent manner (55.9% ± 10.0% vs 69.6% ± 9.6%, 71.9% ± 17.4%, and 76.3% ± 13.3%). Compared with the H/R group, the percentage of apoptotic cells in the GH group significantly decreased (12.38% ± 1.51% vs 6.88% ± 0.87%). Compared with the GH group, the percentage of apoptotic cells in the D + GH group, C + GH group and L + GH groups significantly increased (11.70% ± 0.88%, 11.93% ± 0.96%, 10.20% ± 1.05% vs 6.88% ± 0.87%). There were no significant differences in the percentage of apoptotic cells between the H/R and DM groups (12.38% ± 1.51% vs 13.00% ± 1.13%). There was a significant decrease in LDH release following ghrelin postconditioning compared with the H/R group (561.58 ± 64.01 U/L vs 1062.45 ± 105.29 U/L). There was a significant increase in LDH release in the D + GH, C + GH and L + GH groups compared with the GH group (816.89 ± 94.87 U/L, 870.95 ± 64.06 U/L, 838.62 ± 118.45 U/L vs 561.58 ± 64.01 U/L). There were no significant differences in LDH release between the H/R and DM groups (1062.45 ± 105.29 U/L vs 1017.65 ± 68.90 U/L). Compared with the H/R group, expression of Bcl-2 and Akt increased in the GH group, whereas expression of Bax and GSK3β decreased. Compared with the GH group, expression of Bcl-2 decreased and Bax increased in the D + GH, C + GH and L + GH groups, and Akt decreased and GSK-3β increased in the L + GH group. The H/R group also upregulated expression of VR1 and GSK-3β and downregulated Akt. The number of VR1-positive and Akt-positive cells in the GH group significantly increased, whereas the number of GSK-3β-positive cells significantly decreased. These effects of ghrelin were reversed by capsazepine and LY294002.CONCLUSION: Ghrelin postconditioning protected against H/R-induced injury in human gastric epithelial cells, which indicated that this protection might be associated with GHS-R, VR1 and the PI3K/Akt signaling pathway.

Effects of broth culture filtrate protein of VacA^＋ Helicobacterpylori on the proliferation and apoptosis of gastric epithelial cells

Background Infection with Helicobacter pylori （H. pylon） may lead to chronic inflammation of the stomach epithelium, mucosal atrophy, imbalance of proliferation and apoptosis of epithelial cells; resulting in chronic gastritis, peptic ulcer, gastric cancer, and many other clinical outcomes. Why and how H. pylorus leads to gastric cancer is not clear yet. Through in vitro experiments, this study evaluated the effects of broth culture filtrate protein （BCF-P） from the supernatant of liquid culture media of H. pylori on proliferation and apoptosis of immortalized human gastric epithelial cell lines （GES-1）and gastric cancer cell lines （AGS）. Methods For the study, GES-1 and AGS cell lines mix with BCF-P and epidermal growth factor （EGF）. MTT assay and flow cytometry （FCM） determined the levels of proliferation and apoptosis. Detected expression levels of cyclooxygenase-2 （COX-2） and Fas mRNA by reverse transcription （RT）-PCR. Also did analysis of the effects of BCF-P on epidermal growth factor receptor （EGFR） tyrosine kinase activity of GES-1 and AGS cells by non-radioactive enzyme-linked assay. The Student＇s t test and one-way analysis of variance （ANOVA） were used for statistical analysis. Results BCF-P inhibited proliferation of GES-1 and AGS cells in a concentration-dependent manner. The inhibition rates are respectively 68.7% in AGS and 61.4% in GES-1. With the same dose and time for inhibiting the proliferation, BCF-P failed to induce apoptosis of GES-1 and AGS cells. Effects of BCF-P reduced the expression of Fas mRNA of GES-1 and AGS cells （P 〈0.05）. This is consistent with the effects of EGF. BCF-P reduced the expression of COX-2 mRNA of AGS cells （P 〈0.05）. This is opposite to the effects of EGF （P 〈0.05）. Effects of BCF-P improved more than three times the EGFR tyrosine kinase activity of GES-1 and AGS cells. Conclusions BCF-P inhibited the proliferation of AGS and GES-1 cells in vitro, unrelated to apoptosis. Effects of BCF-P on gastric epithelial cells in vitro are not equivalent to that of EGF.

Effect of bile salts and bile acids on human gastric mucosal epithelial cells

Objective：To explore the effect of bile salt and bile acid on cultured eternalized human gastric mucosa epithelium GES-1 cells. Methods：Cultured eternalized human gastric mucosa epithelium GES-1 cells were treated with media containing 6 different kinds of bile salts and 3 different kinds of bile acids and their mixture with different concentrations： GCDC（glycochenodeoxychoμte）, GDC （glycodeoxychoμte）, GC（glycochoμte）, TCDC（taurochenodeoxychoμte）, TDC（taurodeoxychoμte）, TC （taurochoμte）, LCA （lithocholicacid）, CA（cholic acid）, DCA（deoxycholic acid）（50 μ mol/L,250 μ mol/L,500 μ mol/L,1000 μ mol/L）, DY（mixture of bile salts） and DS（mixture of bile acids）（250 μ mol/L,500 μ mol/L,1000 μ mol/L,1500 μ mol/L, 2000 μ mol/L）, in comparison with the control group（in normal media without bile salts and bile acids）. Cell proliferation was assessed by MTT（3-[4,5-Dimethylthiaolyl]-2,5- diphenyl-tetrazolium bromide） assay for 72 hours with different concentrations and the apoptotic cells were assayed by flow cytometry （FCM） with Annex V-FITC conjugated with propidium iodide（PI） staining for 24 hours with different concentrations（1500,2000 μt mol/L）. Results：There was no significant difference in morphology and cell proliferation in GC group after 24-72 h. Low concentration（50 μ mol/L） of GCDC, GDC, TCDC, TDC and TC accelerated gastric epithelial cell growth in a dosage-time dependent manner. At middle concentration （250-500 μ mol/L）, it showed positive effect after 24-48 h, while negative effect after 72 h. At high concentration（1000 μ mol/L）, it accelerated gastric epithelial cell growth after 24h and show consistent inhibition even leading to necrosis after 48-72 h. LCA and CA showed a positive effect on the concentration of 50 μ mol/L after 24-72 h, while 250-1000 μ mol/L showed a trend towards apoptosis after 24-72 h. At 50-500 μmol/L, DCA showed proliferation after 24 h and apoptosis after 48-72 h, but showed necrosis after 24-72 h at 1000 μmol/L. DY and DS could facilitate normal gastric mucosa epithelial cell growth at low concentration （250-500 μ mol/L）, however at 1000-2000 μ mol/L the trend shifted from apoptosis to necrosis. FCM with Annexin-V conjugated with PI staining revealed that GCDC, GDC, GC, TCDC, TDC, TC, LCA, CA, DCA, DY and DS induced apoptosis of human gastric mucosal epithelial cells. They were all significantly higher than that of the control（P 〈 0.05）, but there was no significant difference in GC group （P 〉 0.05）. The bile salts induced apoptosis in a time-dose-dependent manner. Conclusion：Our results suggested that bile acid and bile salt is the trigger of injury in human gastric mucosal epithelial cells.

Erythropoietin -induced proliferation of gastric mucosal cells

AIM： To analyze the localization of erythropoietin receptor on gastric specimens and characterize the effects of erythropoietin on the normal gastric epithelial proliferation using a porcine gastric epithelial cell culture model. METHODS： Erythropoietin receptor was detected by RT-PCR, Western blotting and immunohistochermistry. Growth stimulation effects of erythropoietin on cultured gastric mucosal cells were determined by ELISA using bromodeoxyuridine （BrdU）. RESULTS： Erythropoietin receptor was detected on cultured porcine gastric mucosal epithelial cells. Erythropoietin receptor was also detected histochemically at the base of gastric mucosal epithelium. BrdU assay demonstrated a dose-dependent increase in growth potential of cultured porcine gastric mucosal epithelial cells by administration of erythropoietin, as well as these effects were inhibited by administration of antierythropoietin antibody （P〈 0.01）. CONCLUSION： These findings indicate that erythropoietin has a potential to proliferate gastric mucosal epithelium via erythropoietin receptor.

H pylori receptor MHC class Ⅱ contributes to the dynamic gastric epithelial apoptotic response

AIM： TO investigate the role of MHC class Ⅱ in the modulation of gastric epithelial cell apoptosis induced by H pylori infection. METHODS： After stimulating a human gastric epithelial cell line with bacteria or agonist antibodies specific for MHC class Ⅱ and CD95, the quantitation of apoptotic and anti-apoptotic events, including caspase activation, BCL-2 activation, and FADD recruitment, was performed with a fluorometric assay, a cytometric bead array, and confocal microscopy, respectively. RESULTS： Pretreatment of N87 cells with the anti-MHC class Ⅱ IgM antibody RFD1 resulted in a reduction in global caspase activation at 24 h of H pylori infection. When caspase 3 activation was specifically measured, crosslinking of MHC class Ⅱ resulted in a marked reduced caspase activation, while simple ligation of HHC class Ⅱ did not. Crosslinking of HHC class Ⅱ also resulted in an increased activation of the anti-apoptosis molecule BCL-2 compared to simple ligation. Confocal microscope analysis demonstrated that the pretreatment of gastric epithelial cells with a crosslinking anti-HHC class Ⅱ IgH blocked the recruitment of FADD to the cell surface. CONCLUSION： The results presented here demonstrate that the ability of MHC class Ⅱ to modulate gastric epithelial apoptosis is at least partially dependent on its crosslinking. Furthermore, while previous research has demonstrated that MHC class Ⅱ signaling can be proapoptotic during extended ligation, we have shown that the crosslinking of this molecule has anti-apoptotic ef-fects during the earlier time points of Hpylori infection. This effect is possibly mediated by the ability of MHC class Ⅱ to modulate the activation of the pro-apoptotic receptor Fas by blocking the recruitment of the accessory molecule FADD, and this delay in apoptosis induction could allow for prolonged cytokine secretion by Hpyloriinfected gastric epithelial cells.

CD74 and macrophage migration inhibitory factor as therapeutic targets in gastric cancer

AIM:To investigate the relationship and molecular features of CD74/macrophage migration inhibitory factor(MIF)/Toll-like receptor 4(TLR4) in gastric cancer.METHODS:CD74,MIF and TLR4 expression in the paraffin-embedded sections of gastric cancer from 120 patients were detected by immunohistochemical staining.Knock down of CD74 expression in gastric cancer cell line MKN-45 was performed by lentivirus transduction and detected by Western blotting.MKN-45 cell proliferation assay under the stimulants was measured by the cell counting kit 8(CCK8) assay and MIF concentration in the culture medium was detected by enzymelinked immunosorbent assay.Surface staining of CD74 in the MKN-45 cell line under the stimulation of lipopolysaccharide(LPS) was measured by flow cytometry.MIF,CD74 and TLR4 co-localization in the MKN-45 cell line was performed by the immunoprecipitation.RESULTS:CD74,MIF and TLR4 were found to be expressed in gastric cancer and increased significantly in the advanced stage,and were also associated with lymph node metastasis.Correlation analysis revealed that CD74 was positively correlated with MIF(r = 0.2367,P < 0.01) and both proteins were also associated with TLR4(r = 0.4414,r = 0.5001,respectively,P < 0.01).LPS can significantly promote MKN-45 cell proliferation(3.027 ± 0.388 vs 4.201 ± 0.092,P < 0.05),induce MIF production(54.333 ± 2.906 pg/mL vs 29.667 ± 3.180 pg/mL,P < 0.01) and cell surface expression of CD74(75.6% ± 4.046%vs 9.4% ± 0.964%,P < 0.01) at LPS concentration of 1 μg/mL compared to medium control.Knockdown of CD74 or using antiCD74 and MIF antagonist ISO-1 significantly reduced LPS-induced MKN-45 cell proliferation(4.201 ± 0.092 vs 3.337 ± 0.087,4.534 ± 0.222 vs 3.368 ± 0.290,4.058 ± 0.292vs 2.934 ± 0.197,respectively,P < 0.01).MIF,CD74 and TLR4 could co-localize in the MKN-45 cell line.CONCLUSION:Upregulation of MIF,CD74 and TLR4 are associated with increasing clinical stage and provide an opportunity as novel gastric cancer chemoprevention and/or treatment strategy.

Telomerase and hTERT: Can they serve as markers for gastric cancer diagnosis?

AIM: To investigate telomerase activity and human telomerase reverse transcriptase (hTERT) expression in normal human gastric mucosal epithelial cells (nhGMECs) and fibroblasts (nhGMFs).

Immune evasion strategies used by Helicobacter pylori

Helicobacter pylori(H. pylori) is perhaps the most ubiquitous and successful human pathogen, since it colonizes the stomach of more than half of humankind. Infection with this bacterium is commonly acquired during childhood. Once infected, people carry the bacteria for decades or even for life, if not treated. Persistent infection with this pathogen causes gastritis, peptic ulcer disease and is also strongly associated with the development of gastric cancer. Despite induction of innate and adaptive immune responses in the infected individual, the host is unable to clear the bacteria. One widely accepted hallmark of H. pylori is that it successfully and stealthily evades host defense mechanisms. Though the gastric mucosa is well protected against infection, H. pylori is able to reside under the mucus, attach to gastric epithelial cells and cause persistent infection by evading immune responses mediated by host. In this review, we discuss how H. pylori avoids innate and acquired immune response elements, uses gastric epithelial cells as mediators to manipulate host T cell responses and uses virulence factors to avoid adaptive immune responses by T cells to establish a persistent infection. We also discuss in this review how the genetic diversity of this pathogen helps for its survival.

Helicobacter pylori gamma-glutamyl transpeptidase and its pathogenic role

Helicobacter pylori(H.pylori)gamma-glutamyl transpeptidase(GGT)is a bacterial virulence factor that converts glutamine into glutamate and ammonia,and converts glutathione into glutamate and cysteinylglycine.H.pylori GGT causes glutamine and glutathione consumption in the host cells,ammonia production and reactive oxygen species generation.These products induce cell-cycle arrest,apoptosis,and necrosis in gastric epithelial cells.H.pylori GGT may also inhibit apoptosis and induce gastric epithelial cell proliferation through the induction of cyclooxygenase-2,epidermal growth factor-related peptides,inducible nitric oxide synthase and interleukin-8.H.pylori GGT induces immune tolerance through the inhibition of T cell-mediated immunity and dendritic cell differentiation.The effect of GGT on H.pylori colonization and gastric persistence are also discussed.

Effect of cagE gene on Helicobacter pylori-associated gastritis and levels of interleukin-8

Objective: To investigate the status of cagE gene of Helicobacter pylori(H. pylori) isolated from patients with various gastrointestinal diseases and its relationship with the pathological inflammation grade and levels of IL 8 in the gastric mucosa and IL 8 secretion in gastric epithelial cells stimulated by H. pylori . Methods: cagE was amplified by polymerase chain reaction (PCR) in 145 clinical isolates. The inflammation grade of gastric mucosa was evaluated pathologically. IL 8 levels of gastric mucosa and IL 8 concentration of the supernatant of the cocultured SGC 7 901 cells and H. pylori was assayed by enzyme linked immunosorbent assay (ELISA). Results: cagE was positive in 79.3% of all the H. pylori strains. The mean score of the cagE positive gastritis in the antrum and corpus was (1.865±0.335) and (1.759±0.310). Meanwhile, the cagE negative grade was (1.689±0.294), (1.608±0.284). There was no significant difference ( P >0 05). The mean levels of IL 8 in cagE positive group in antrum and corpus were (390.6±101.4) pg/mg and (368.6±91.2) pg/mg; and cagE negative group were (328.6±102.8) pg/mg and (332.6±96.7) pg/mg. IL 8 in SGC7901 cells induced by cagE positive and negative group averaged (789.5±146.7) pg/ml and (757.6±136.4) pg/ml. There was still no significant difference( P >0.05). Conclusion: Positive rate of cagE is very high in Chinese patients regardless of the clinical outcome. And there was no direct relationship between cagE gene and the inflammation grade and IL 8 levels of H. pylori infected gastric mucosa and IL 8 secretion in gastric epithelial cells stimulated by H. pylori .