Piceatannol, a natural hydroxylated analog of resveratrol, promotes nitric oxide release through phosphorylation of endothelial nitric oxide synthase in human endothelial cells.

OBJECTIVE: Endothelial dysfunction associated with many cardiovascular diseases is largely due to reduced nitric oxide (NO) derived from endothelial NO synthase (eNOS). Piceatannol (trans-3,4,3',5'-tetrahydroxystilbene; Pic) is reported to have cardiovascular therapeutic effects. However, the cellular and molecular mechanisms underlying the cardioprotective effects of Pic are still unclear. Here, we investigated whether Pic could influence endothelial NO release in human umbilical vein endothelial cells (HUVECs). MATERIALS AND METHODS: In HUVECs exposed to Pic, NO production and phosphorylation of eNOS and protein kinase B (Akt) were determined by using a commercially available NO assay kit and Western blot analysis, respectively. RESULTS: Pic stimulated dose- and time-dependent NO production via eNOS phosphorylation. Pic also stimulated dose-dependent phosphorylation of Akt. Interestingly, NO production and eNOS phosphorylation in response to Pic were significantly abolished by the phosphoinositide 3-kinase (PI3K)/Akt inhibitor LY294002. CONCLUSIONS: Pic is capable of inducing eNOS phosphorylation and the subsequent NO release, presumably, by activating PI3K/Akt pathway. The potential efficacy of Pic, a natural hydroxylated analog and a metabolite of resveratrol, may aid in the prevention of cardiovascular diseases characterized by endothelial dysfunction.

Risks related with withholding and resuming anticoagulation in patients with non-variceal upper gastrointestinal bleeding while on warfarin therapy.

BACKGROUND: The use of warfarin is growing for the prevention or treatment of cardiovascular or cerebrovascular diseases. The risk of haemorrhagic side effects is increased in patients taking warfarin. AIMS: To evaluate risks related with withholding and resuming anticoagulation in patients with upper gastrointestinal bleeding (UGIB) while on warfarin therapy and the role of the second-look endoscopic examination (SEE). METHODS: Records of 58 patients with native valvular heart diseases who presented with non-variceal UGIB during chronic anticoagulation with warfarin were retrospectively reviewed. Age- and gender-matched patients with non-variceal UGIB during aspirin therapy because of ischaemic heart disease were recruited as the control group. RESULTS: Development of both recurrent bleeding and thromboembolic events were more frequent in warfarin group than in control group (7.0% vs. 0% with p = 0.03 and 16.7% vs. 2.4% with p < 0.01, respectively). One of four cases of recurrent bleeding in warfarin group was found by SEE performed in an asymptomatic patient. There were six thromboembolic events which occurred on the 21st, 27th, 28th, 31st, 58th and 75th day from the presentation out of 36 patients who ceased anticoagulation. In contrast, only one from 41 in whom aspirin was discontinued experienced myocardial infarction. There was no difference in the failure of endoscopic haemostasis necessitating angiographic embolisation or surgery, hospital stay, the need of transfusion and overall mortality. CONCLUSIONS: Anticoagulation is recommended to be resumed before the 20th day from the cessation to prevent thromboembolic events. A routine SEE before resuming anticoagulation might be helpful to detect asymptomatic recurrent bleeding.

DNA capturing machinery through spore-displayed proteins.

AIMS: The purpose of this study was to develop a general method for the facile development of a new DNA biosensor which utilizes streptavidin-displayed spores as a molecular machinery. METHODS AND RESULTS: Fluorescence spectroscopy was used as a monitoring tool for the streptavidin displayed on the surface of Bacillus thuringiensis spores and as a diagnosis method for DNA detection. As a proof-of-concept, four pathogenic bacteria including Pseudomonas aeruginosa, Acinetobacter baumannii, Escherichia coli and Klebsiella pneumonia were used for the detection of pathogenic species. In addition, a set of mutant variants of Wilson's disease were also used for the detection of single nucleotide polymorphism (SNP) in this system. CONCLUSIONS: This strategy, utilizing streptavidin-displayed spores, is capable of capturing DNA targets for the detection of pathogenic bacteria and for mutation analysis in Wilson's disease. SIGNIFICANCE AND IMPACT OF THE STUDY: This approach could be useful as a simple platform for developing sensitive spore-based biosensors for any desired DNA targets in diagnostic applications.

Comparison of endoscopic ultrasonography and conventional endoscopy for prediction of depth of tumor invasion in early gastric cancer.

BACKGROUND AND STUDY AIMS: This study aimed to compare the diagnostic accuracy of endoscopic ultrasonography (EUS) with that of conventional endoscopy for staging depth of invasion (T staging) in early gastric cancer. PATIENTS AND METHODS: A total of 955 patients with suspected early gastric cancer were prospectively registered. EUS staging was carried out prospectively by a single endoscopist using either miniprobe or radial EUS depending on the endoscopic appearance of the tumor. Conventional endoscopy staging was performed retrospectively by consensus between two endoscopists who were blinded to the EUS staging. Conventional endoscopy staging was conducted on the basis of endoscopic features such as surface nodularity and fold convergence. Patients underwent either surgical (n = 586) or endoscopic resection (n = 369) with curative intent. The staging accuracy of each test was compared with the pathological staging of the resected specimen. RESULTS: The presence of a T1m tumor was histologically confirmed in 644 cases (67.4 %) and that of a T1sm tumor in 311 cases (32.6 %). The overall accuracy of EUS staging was 67.4 % (644 / 955) and that of conventional endoscopy staging was 73.7 % (704 / 955) ( P < 0.001). The accuracy of miniprobe EUS was significantly higher than that of radial EUS (79.5 % vs. 59.6 %, P < 0.001), but did not differ significantly from that of conventional endoscopy (79.0 %). CONCLUSIONS: EUS does not substantially impact on pretreatment T staging of patients with early gastric cancer compared with conventional endoscopy. Therefore, EUS may not be necessary routinely, and conventional endoscopy may be sufficient for determining the optimal therapeutic strategy, especially in relation to endoscopic resection for early gastric cancer.

Comparison of risk factors and clinical responses to proton pump inhibitors in patients with erosive oesophagitis and non-erosive reflux disease.

BACKGROUND: There has been no report on the response to proton pump inhibitor (PPI) therapy and on-demand or the relapse rate of non-erosive reflux disease (NERD) and erosive oesophagitis in Korea. AIM: To compare the risk factors, clinical symptoms and PPI responses between patients with erosive oesophagitis and NERD patients. METHODS: A survey was performed prospectively in the erosive oesophagitis (205 patients) and NERD group (200 patients). Clinical symptoms, risk factors and PPI responses were analysed. On-demand therapy and the relapse rate of GERD symptoms were investigated during a one-year follow-up. RESULTS: BMI > or = 25 (OR 3.0, 95% CI 1.1-8.3), alcohol use (OR 2.9, 95% CI 1.0-8.3), hiatal hernia (OR 5.0, 95% CI 1.2-20) and triglyceride > or =150 mg/dL (OR 4.0, 95% CI 1.7-10) were more common in the erosive oesophagitis group than in the NERD group by multivariate analysis. The ratio of oesophageal to extra-oesophageal symptoms was higher in the erosive oesophagitis group compared with the NERD group (P < 0.001). The PPI response rates at 8 weeks were different (P = 0.02); refractory rates were higher in the NERD group (16.7%) compared with the erosive oesophagitis group (6.0%). However, there was no significant difference between the two groups in on-demand therapy or the relapse rate. CONCLUSION: These results suggest that the underlying pathogenic mechanisms of erosive oesophagitis and NERD are distinct.

5,7-dihydroxy-3,4,6-trimethoxyflavone inhibits the inflammatory effects induced by Bacteroides fragilis enterotoxin via dissociating the complex of heat shock protein 90 and I kappaB alpha and I kappaB kinase-gamma in intestinal epithelial cell culture.

Enterotoxin produced by enterotoxigenic Bacteroides fragilis (BFT) has been associated with mucosal inflammation and diarrhoeal diseases. In this study, the anti-inflammatory molecular mechanism of 5,7-dihydroxy-3,4,6-trimethoxyflavone (eupatilin) was characterized in an HT-29 intestinal epithelial cell line stimulated with BFT. Pre-treatment of HT-29 cells with eupatilin decreased the production significantly of both interleukin (IL)-8 and prostaglandin E(2) induced by BFT in a dose-dependent manner. BFT-activated nuclear factor-kappaB (NF-kappaB) signals in HT-29 cells and pretreatment with eupatilin suppressed NF-kappaB activation that resulted in the significant inhibition of IL-8 and cyclo-oxygenase-2 expression. BFT-induced phosphorylation of both I kappaB alpha and I kappaB kinase (IKK) signals was prevented in eupatilin-pretreated HT-29 cells. Transfection of siRNA for IKK-alpha and IKK-beta decreased the production of IL-8 and prostaglandin E(2); however, the transfection of IKK-beta siRNA showed a more significant reduction of BFT-induced I kappaB alpha phosphorylation compared with that of IKK-alpha siRNA. In addition, herbimycin A, a specific inhibitor of heat shock protein 90 (Hsp90), decreased the BFT-induced activation of IKK and NF-kappaB, suggesting that Hsp90 is associated with a pathway of IKK-NF-kappaB-IL-8/cyclo-oxygenase-2 gene signalling. Furthermore, eupatilin dissociated the complex between Hsp90 and IKK-gamma in BFT-stimulated HT-29 cells. These results suggest that eupatilin can suppress the NF-kappaB signalling pathway by targeting the Hsp90-IKK-gamma complex in intestinal epithelial cells and may attenuate BFT-induced inflammatory responses.

Metabolic syndrome and visceral obesity as risk factors for reflux oesophagitis: a cross-sectional case-control study of 7078 Koreans undergoing health check-ups.

BACKGROUND: Obesity has been associated with reflux oesophagitis. However, the relationship between metabolic syndrome characterised by visceral obesity and reflux oesophagitis is unclear. AIM: To investigate whether metabolic syndrome or visceral obesity is a risk factor for reflux oesophagitis. METHODS: A cross-sectional study of 7078 subjects undergoing upper endoscopy during health check-ups was conducted (3539 patients with reflux oesophagitis vs age- and sex-matched controls). We further analysed according to categories of visceral adipose tissue and subcutaneous adipose tissue area with 750 cases and age-, sex- and waist circumference-matched controls who underwent abdominal CT scan. RESULTS: The prevalence of metabolic syndrome was higher in cases than controls (26.9% vs 18.5%, p<0.001). Multivariate analysis demonstrated that metabolic syndrome is associated with reflux oesophagitis (odds ratio (OR) = 1.42; 95% confidence interval (CI), 1.26 to 1.60). Among the individual components of metabolic syndrome, waist circumference (OR = 1.47; 95% CI, 1.30 to 1.65) and triglyceride (OR = 1.20; 95% CI, 1.05 to 1.36) independently increased the risk for reflux oesophagitis. On sub-analysis, cases showed higher mean visceral adipose tissue area (cm(2)) (136.1 (SD 57.8) vs 124.0 (SD 54.7), p<0.001) and subcutaneous adipose tissue area (cm(2)) (145.9 (SD 56.8) vs 133.5 (SD 50.7), p<0.001). However, only visceral adipose tissue area was an independent risk factor for reflux oesophagitis after adjusting for multiple confounders including smoking, alcohol, body mass index (BMI) and subcutaneous adipose tissue area (OR = 1.60; 95% CI, 1.03 to 2.48, lowest quartile vs highest quartile). CONCLUSIONS: Metabolic syndrome was associated with reflux oesophagitis. Abdominal obesity, especially visceral obesity, was an important risk factor for reflux oesophagitis.

Efficacy and safety of solifenacin succinate in Korean patients with overactive bladder: a randomised, prospective, double-blind, multicentre study.

PURPOSE: We assessed the efficacy and safety of solifenacin compared with tolterodine for treatment of overactive bladder (OAB) in Korean patients. MATERIALS AND METHODS: The study was randomised, double-blind, tolterodine-controlled trial in Korea. Patients had average frequency of >or= 8 voids per 24 h and episodes of urgency or urgency incontinence >or= 3 during 3-day voiding diary period. Patients were randomised to 12-week double-blind treatment with either tolterodine immediate release (IR) 2 mg twice daily (TOL4) or solifenacin 5 mg (SOL5) or 10 mg (SOL10) once daily. The outcome measure was mean change in daily micturition frequency, volume, daily frequency of urgency incontinence, urgency and nocturia from baseline to week 12. Quality of life was assessed using the King's Health Questionnaire. RESULTS: A total of 357 were randomised and 329 were evaluated for efficacy. All voiding parameters recorded in micturition diary improved after treatment in all three groups. Mean changes in volume voided were 19.30 ml (26.69%) in TOL4, 30.37 ml (25.89%) in SOL5 and 37.12 ml (33.36%) in SOL10 group (p = 0.03). Speed of onset of SOL10 efficacy on urgency incontinence was faster than that of SOL5 and TOL4. Quality of life improved in all three groups. Dry mouth was the most common adverse event; its incidence was the lowest in SOL5 group (7.63%, compared with 19.49% and 18.64% in SOL10 and TOL4 groups respectively). CONCLUSIONS: Solifenacin succinate 5 and 10 mg once daily improve OAB symptoms with acceptable tolerability levels compared with tolterodine IR 4 mg. Solifenacin 5 mg is a recommended starting dose in Korean patients with OAB.

The prevalence of and risk factors for erosive oesophagitis and non-erosive reflux disease: a nationwide multicentre prospective study in Korea.

BACKGROUND: Prospective nationwide multicentre studies that have evaluated endoscopic findings and reflux symptoms using a well-designed questionnaire are very rare. AIM: To compare the prevalence rates of and risk factors for erosive oesophagitis and non-erosive reflux disease (NERD) in the Korean population. METHODS: A gastroscopic examination was performed on 25 536 subjects who visited 40 Healthcare Centers for a health check-up. A gastro-oesophageal reflux questionnaire and multivariate analysis were used to determine the risk factors for erosive oesophagitis and NERD. RESULTS: 2019 (8%) and 996 subjects (4%) had erosive oesophagitis and non-erosive reflux disease, respectively; only 58% of subjects with erosive oesophagitis had reflux symptoms. Multivariate analysis showed that the risk factors for erosive oesophagitis and NERD differed, i.e. those of erosive oesophagitis were male, a Helicobacter pylori eradication history, alcohol, body mass index > or =25 and hiatal hernia. In contrast, the risk factors for NERD were female, age <40 and > or =60 vs. 40-59 years, body mass index <23 and a monthly income <$1000, glucose > or =126 mg/dL, smoking, a stooping posture at work and antibiotic usage. CONCLUSIONS: The prevalence rates of erosive oesophagitis and NERD were 8% and 4%, respectively, in Korean health check-up subjects. The risk factors for erosive oesophagitis and NERD were found to differ, which indicates that their underlying pathogeneses are distinct.

Helicobacter pylori eradication for low-grade gastric mucosa-associated lymphoid tissue lymphoma is more successful in inducing remission in distal compared to proximal disease.

A series of studies has shown that Helicobacter pylori eradication induces remission in most patients with low-grade gastric mucosa-associated lymphoid tissue (MALT) lymphoma. However, there have been few reports about the effect of bacterial treatment on the gastric MALT lymphoma in Korea, a well-known H. pylori endemic area. A total of 111 H. pylori-infected patients were prospectively enrolled in Seoul National University Hospital and 99 among them were completely followed up according to our protocol. After H. pylori eradication, tumoural response was evaluated by endoscopy and histopathology every 2-3 months till complete remission (CR) and every 6 months after achieving CR. Median follow-up period was 41 months (range, 11-125 months). Helicobacter pylori was successfully eradicated in all 99 patients and CR was obtained in 84 (84.8%) of 99 patients. The median time to reach CR was 3 months and 94% of CR is in continuous complete remission. Five patients with CR relapsed after 10-22 months without the evidence of H. pylori reinfection. Cumulative recurrence rate was 2.3, 7.7 and 9.3% at 1, 2 and 3 years, respectively. Tumours were mainly located in distal stomach (67.7%) and tumours in distal stomach were associated with more favourable response than those in proximal stomach (P=0.001). Majority of patients with low-grade gastric MALT lymphoma treated by exclusive H. pylori eradication have a favourable long-term outcome, offering a real chance of cure. Tumour location could be a predictive factor for remission following H. pylori eradication.

Omeprazole may be superior to famotidine in the management of iatrogenic ulcer after endoscopic mucosal resection: a prospective randomized controlled trial.

BACKGROUND: Acid suppressing agents are widely used to treat the iatrogenic ulcers following endoscopic mucosal resection for gastric neoplasms. However, the relative merits of proton pump inhibitor or histamine(2)-receptor antagonist for endoscopic mucosal resection-induced ulcers are not known. AIM: To prospectively compare omeprazole and famotidine for the healing of endoscopic mucosal resection-induced ulcers and for bleeding control. METHODS: After endoscopic mucosal resection, patients were randomly assigned to omeprazole (20 mg/day) or to famotidine (40 mg/day) group for a 28-day treatment period. The ulcer sizes and stages, bleeding rates and ulcer-related symptoms were compared. RESULTS: A total of 100 patients were randomized equally to each group. Forty-one patients in each group were finally compared. The two groups were comparable in terms of baseline characteristics. Twenty-eight days after treatment, the two groups were not different with respect to ulcer stage (P = 0.137) or ulcer reduction ratio (P = 0.380). No difference was observed with respect to ulcer-related symptoms (P = 0.437) and no bleeding episode occurred in any of the 82 patients. In subgroup that underwent endoscopic submucosal dissection, fewer patients in the omeprazole group showed active ulcers than those in the famotidine group (P = 0.035). CONCLUSION: Our results demonstrate that omeprazole may be superior to famotidine for iatrogenic ulcers following endoscopic mucosal resection, especially for large ulcers.

Intraoperative gastroscopy for gastric surgery.

BACKGROUND: Few reports are available on the use of intraoperative gastroscopy for gastric surgery. METHODS: The details of 33 patients (25 early gastric cancers and eight gastric submucosal tumors) who underwent intraoperative gastroscopy from June 2003 to June 2004 were analyzed. The type of operation or resection margin was determined by evaluating both sides of the stomach simultaneously by combined operative and gastroscopic methods. RESULTS: Preoperative endoscopic clipping was done preferentially for early gastric cancer. However, when precise localization was needed, intraoperative gastroscopy was used. Curative gastric resection was possible in 25 early gastric cancer patients after accurate lesion localization. Laparoscopic wedge resections of submucosal tumors were performed in seven patients without stenosis by combined laparoscopic and gastroscopic methods. CONCLUSIONS: Intraoperative gastroscopy can be used effectively during gastric surgery for early gastric cancer or submucosal tumors and can be regarded as a modern stethoscope to gastric surgeons.

The effect of rebamipide on the expression of proinflammatory mediators and apoptosis in human neutrophils by Helicobacter pylori water-soluble surface proteins.

BACKGROUND: Helicobacter pylori infection elicits persistent neutrophil infiltration in gastric mucosa. The expression of cyclooxygenase (COX)-2 and inhibition of apoptosis in the neutrophils could contribute to the pathogenesis of H. pylori infection. Rebamipide, a mucosal protective and ulcer-healing drug, has been known to inhibit neutrophil activation. AIM: To evaluate the effect of rebamipide on the neutrophils activated by H. pylori water-soluble proteins. METHODS: After neutrophils were stimulated with H. pylori water extract (HPWE) or pre-treated with rebamipide, the expression of COX-2 mRNA and protein was assessed by quantitative RT-PCR and Western blotting, respectively. Prostaglandin (PG) E2 synthesis was determined by radioimmunoassay. Neutrophil apoptosis was evaluated by cytosolic oligonucleosome-bound DNA ELISA and caspase-3 activity was measured by the detection of p-nitroanilide after cleavage from labelled substrate. RESULTS: Stimulation with HPWE up-regulated COX-2 expression and PGE2 secretion, and inhibited neutrophil apoptosis. Rebamipide suppressed PGE2 secretion from neutrophils dose-dependently. Rebamipide, however, did not affect neutrophil apoptosis and caspase-3 activity. CONCLUSIONS: Rebamipide effectively suppressed PGE2 secretion from neutrophils activated by H. pylori water-soluble proteins. This is another possible mechanism of gastric mucosal protection by rebamipide.

Is a 9-month treatment sufficient in tuberculous enterocolitis? A prospective, randomized, single-centre study.

BACKGROUND: Tuberculosis has increased in parallel with the acquired immunodeficiency syndrome epidemic and the use of immunosuppressive therapy, and the growing incidence of extra-pulmonary tuberculosis, especially with intestinal involvement, reflects this trend. However, the duration of anti-tuberculous therapy has not been clarified in intestinal tuberculosis. AIM: To compare the efficacy of different treatment durations in tuberculous enterocolitis in terms of response and recurrence rates. METHODS: Forty patients with tuberculous enterocolitis were randomized prospectively: 22 patients into a 9-month and 18 into a 15-month group. Diagnosis was made either by colonoscopic findings of discrete ulcers and histopathological findings of caseating granuloma and/or acid-fast bacilli, or by clinical improvement after therapeutic trial. Patients were followed up with colonoscopy every other month until complete response or treatment completion, and then every 6 months for 1 year and annually. Complete response was defined as a resolution of symptoms and active tuberculosis by colonoscopy. RESULTS: Complete response was obtained in all patients in both groups. Two patients in the 9-month group and one in the 15-month group underwent operation due to intestinal obstruction and perianal fistula, respectively. No recurrence of active intestinal tuberculosis occurred during the follow-up period in either group. CONCLUSIONS: Tuberculous enterocolitis can be managed by 9-month chemotherapy without disease recurrence. Further investigations are needed in immunocompromised patients.

Effect of Helicobacter pylori eradication on duodenal ulcer scar in patients with no clinical history of duodenal ulcer.

BACKGROUND: Helicobacter pylori eradication has become the standard treatment for duodenal ulcer. However, there is no relevant evidence for antibacterial treatment of the white scar stage of duodenal ulcer (duodenal ulcer scar) in patients with no past history of duodenal ulcer. AIM: To investigate whether H. pylori eradication could decrease duodenal ulcer recurrence in patients with duodenal ulcer scar and no past history of duodenal ulcer. PATIENTS AND METHODS: We prospectively enrolled 66 patients with duodenal ulcer scar: 53 were H. pylori-positive and 13 were H. pylori-negative. H. pylori-positive patients were randomly assigned into two groups (two-to-one allocation): 36 patients were assigned to the treatment group and 17 to the follow-up group. Thirteen H. pylori-negative patients were followed up according to the study protocol. Follow-up endoscopy was performed to evaluate ulcer scar changes and H. pylori status 6 weeks after anti-H. pylori treatment and then every 6 months for up to 30 months. RESULTS: Active duodenal ulcer recurrence was identified in seven of 23 H. pylori-positive/non-cured patients (30%). There was no duodenal ulcer recurrence in 43 H. pylori-negative/cured patients (0%), which was significantly different in terms of duodenal ulcer recurrence (P=0.001). CONCLUSIONS: H. pylori eradication is effective at preventing active duodenal ulcer recurrence in patients with duodenal ulcer scar and no past history of duodenal ulcer.

Efficacy of low-dose clarithromycin triple therapy and tinidazole-containing triple therapy for Helicobacter pylori eradication.

BACKGROUND: Proton pump inhibitor-based triple therapies are recommended as the first-line treatment for Helicobacter pylori eradication. AIM: To evaluate the efficacies of low-dose clarithromycin triple therapy and tinidazole-containing triple therapy in a metronidazole resistance prevalent area and to compare the efficacies with standard triple therapy. METHODS: In a randomized, multicentre, prospective study, a total of 352 patients with duodenal ulcer or non-ulcer dyspepsia were randomly divided into three groups according to the administered regimen: OAC250 group (omeprazole, 20 mg, amoxicillin, 1000 mg, and clarithromycin, 250 mg), OAC500 group (omeprazole, 20 mg, amoxicillin, 1000 mg, and clarithromycin, 500 mg) and OTC group (omeprazole, 20 mg, tinidazole, 500 mg, and clarithromycin, 500 mg). The three groups received each regimen twice daily for 7 days. Upper gastrointestinal endoscopy was performed before and 4 weeks after treatment. H. pylori status was determined by rapid urease test and 13C urea breath test. RESULTS: The eradication rates in the OAC250, OAC500 and OTC groups were 76.2%, 65.7% and 64.8% (95% confidence interval: 67.9-84.4%, 56.7-74.8% and 55.7-73.9%), respectively, by intention-to-treat analysis (P=0.149) and 92.8%, 87.2% and 84.1% (95% confidence interval: 84.4-97.3%, 77.9-93.8% and 73.9-91.2%), respectively, by per protocol analysis (P=0.088). All regimens were well tolerated and compliance was excellent. CONCLUSIONS: Both low-dose clarithromycin triple therapy and tinidazole-containing triple therapy are effective and safe regimens for H. pylori eradication.

Caspase-3 activity and expression of Bcl-2 family in human neutrophils by Helicobacter pylori water-soluble proteins.

BACKGROUND: Persistent infiltration of neutrophils is an almost invariable feature of Helicobacter pylori-infected gastric mucosa. A prolongation of neutrophil life-span could contribute to the pathogenesis of H. pylori infection. Recently, we have demonstrated that H. pylori water extracts (HPWE) inhibited neutrophil apoptosis. To elucidate the regulation of intracellular apoptotic signals by HPWE, we examined the activity of caspase-8, -3 and expression of Bcl-2 family in neutrophils. MATERIALS AND METHODS: Human neutrophils were obtained from the peripheral blood of healthy volunteers by density gradient separation. HPWE was prepared from a supernatant of the H. pylori suspension in distilled water. After neutrophils were incubated with HPWE, expression of Bcl-2 family [antiapoptotic (Bcl-2, Bcl-XL and Mcl-1) and proapoptotic (Bax, Bak and Bcl-XS)] was determined by RT-PCR and Western blotting, respectively. Western blot for Bcl-2 family also performed in neutrophilic differentiated HL-60 cells by all-trans-retinoic acid. The activity of caspase-8, -3 was measured by the detection of p-nitroanilide after cleavage from labeled substrate. RESULTS: HPWE suppressed the activation of caspase-8 and -3, and upregulated the expression of Bcl-XL mRNA and proteins in neutrophils. The expression of Bax and Bak was upregulated and Bcl-2, Bcl-XL and Mcl-1 downregulated in HL-60 cells during neutrophilic differentiation. CONCLUSION: Bcl-XL may have an important role in the neutrophilic development and inhibition of neutrophil apoptosis by H. pylori.

Expression of cyclooxygenase-2 in human neutrophils activated by Helicobacter pylori water-soluble proteins: possible involvement of NF-kappaB and MAP kinase signaling pathway.

Helicobacter pylori infection elicits persistent neutrophil infiltration in gastric mucosa. The expression of cyclooxygenase (COX) -2 by the neutrophils results in prostaglandin (PG) E2 synthesis, which may account for alterations in tissue homeostasis. In this study, we found that COX-2 mRNA was up-regulated in the neutrophils when stimulated with both H. pylori water extract (HPWE) and live H. pylori in a transwell model and determined by quantitative RT-PCR. PGE2 synthesis was also enhanced in the neutrophils activated by both the HPWE and live H. pylori. A specific COX-2 inhibitor (NS-398) blocked PGE2 synthesis, and an anti-ulcer agent (rebamipide) suppressed it dose dependently. An NF-kappaB inhibitor (pyrrolidine dithiocarbamate), a MAP kinase (MEK) inhibitor (PD98059), and a p38 MAP kinase inhibitor (SB203580) significantly suppressed the COX-2 gene transcription and PGE2 synthesis in the neutrophils. In conclusion, H. pylori water-soluble proteins may enhance the COX-2 expression, and this action could be mediated through the NF-kappaB and MAP kinase signaling pathways. The increased section of PGE2 by the neutrophils may play a proinflammatory role in the gastric mucosal response to H. pylori.

Inhibition of apoptosis in human neutrophils by Helicobacter pylori water-soluble surface proteins.

BACKGROUND: Helicobacter pylori infection in humans causes persistent neutrophil infiltration into the gastric mucosa. It is believed that a prolongation of neutrophil life-span could contribute to the pathogenesis of H. pylori infection. We therefore examined whether the water-soluble surface proteins of H. pylori can influence the apoptosis of neutrophils. METHODS: After neutrophils were incubated with H. pylori water extract (HPWE), neutrophil apoptosis was evaluated by TUNEL assay, Hoechst 33342 staining, electron microscopy and ELISA for cytosolic oligonucleosome-bound DNA for up to 48 h. To investigate the regulatory mechanisms of neutrophil apoptosis associated with HPWE, mRNA expression and protein production of Fas, Fas ligand (FasL) and tumor necrosis factor receptor 1 (TNF-R1) were analyzed by RT-PCR, ribonuclease protection assay, Northern blot and Western blotting. Cell surface expression of these death factors was also measured by flow cytometry. RESULTS: HPWE inhibited neutrophil apoptosis and cytotoxicity for up to 48 h. The mRNA and protein expression of FasL and the cell surface expression of Fas, FasL and TNF-R1 in HPWE-treated neutrophils were suppressed compared with the controls. CONCLUSION: The water-soluble surface proteins of H. pylori could suppress neutrophil apoptosis. This may be caused by the suppression of FasL expression in neutrophils and Fas, FasL and TNF-R1 expression on the surface of neutrophils.