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While the prevalence of Helicobacter pylori (H. pylori) infection is decreasing in Korea, the incidence of gastric cancer remains high, emphasizing the importance of H. pylori eradication. A new treatment strategy is needed as the eradication rate with standard triple therapy, which is currently the standard first-line regimen for H. pylori infection, has decreased below the optimum level. The major cause of eradication failure is increased antibiotic resistance. Sequential, concurrent, and hybrid therapies that include clarithromycin produce higher eradication rates than conventional standard triple therapy. However, the effectiveness of these treatments is limited in regions where the resistance rate to various antibiotics is high. Bismuth quadruple therapy is another alternative therapy, but again the eradication rate is not sufficiently high. Tailored therapy based on individual characteristics, including antibiotic susceptibility, may be ideal, but there are several limitations for clinical application and further research is needed. New potassium-competitive acid blocker-based therapies could emerge as effective alternatives in the near future. A consensus is needed to establish a strategy for applying new eradication therapies in Korea.

Background/aims: Increased incidence of coronary artery disease has led to the increased use of dual antiplatelet therapy composed of aspirin and clopidogrel. We investigated the incidence of gastrointestinal complications in patients who received single or dual antiplatelet therapy and analyzed their clinical characteristics in order to predict the prognostic factors., Methods: Between January 2009 and December 2011, we retrospectively reviewed the medical records of patients who underwent coronary angiography at Chung-Ang University Hospital (Seoul, Korea). One hundred and ninety-four patients were classified into two groups: aspirin alone group and dual antiplatelet group. Clinical characteristics, past medical history, and presence of peptic ulcer were analyzed., Results: During the follow-up period, 11 patients had duodenal ulcer; the event rate was 2.02% in the aspirin alone group and 9.47% in the dual antiplatelet group (hazard ratio [HR] 5.24, 95% CI 1.03-26.55, p<0.05). There was no significant difference in the rate of significant upper gastrointestinal bleeding: 0% vs. 4.2% (p=0.78). In patients who received proton pump inhibitor (PPI), 24 patients had gastric ulcer; the event rate was significantly different between the two groups: 4.87% vs. 22.98% (HR 3.40, 95% CI 1.02-11.27, p<0.05)., Conclusions: Dual antiplatelet groups had a higher incidence of duodenal ulcers without significant bleeding compared with the aspirin alone group. In patients who received PPI, the dual antiplatelet therapy group had a higher incidence of gastric ulcers without significant bleeding compared with the aspirin alone group. Therefore, physicians must pay attention to high risk groups who receive dual antiplatelet therapy and aggressive diagnostic endoscopy should also be considered.

Peptic ulcer is one of the most prevalent diseases in gastrointestinal field. Recently, evolution was made for pathophysiology of peptic ulcer from "no acid, no ulcer" to Helicobacter pylori and non-steroidal anti-inflammatory drugs. The prevalence of peptic ulcer disease is estimated about 10% in Korea, and has declined due to Helicobacter pylori eradication therapy. Peptic ulcer has the cycle of exacerbation and improvement in the clinical course, and has not occasionally any clinical symptom. Helicobacter pylori eradication has made the marked reduction of relapse of peptic ulcer disease. Although nationwide endoscopic screening has enabled accurate diagnosis of peptic ulcer disease, general guideline for diagnosis of peptic ulcer has not made in Korea. Herein, we propose a guideline for the diagnosis of peptic ulcer according to domestic, international clinical studies, and experts opinions with level of evidence and grade of recommendation.

Background/aims: The aim of this study was to evaluate the changes in prevalence and the related factors of Helicobacter pylori (H. pylori) infection in Korean health check-up subjects during the period of 8 years., Methods: Among 89,231 subjects who visited the Health Promotion Centers of Severance hospital or Chung-Ang University hospital from Jan. 1998 through Dec. 2005, a total of 10,553 subjects who received esophagogastroduodenoscopy (EGD) and H. pylori test were enrolled. H. pylori infection was assessed by histologic examination. Changes of the prevalence of H. pylori infection during 8 years, and infection-related factors such as demographic characteristics, body mass index, ABO blood types, endoscopic findings (presence of peptic ulcer diseases), educational level, economic status, smoking habits, and alcohol intake in year 2005 were analyzed., Results: The mean age of 10,553 subjects (7,329 men, 3,224 women) was 49.7+/-10.4 years (range from 17 to 92 years). The prevalence of H. pylori infection at the first, second, third, fourth, fifth, sixth, seventh, and eighth year were 64.7%, 58.1%, 54.2%, 50.4%, 48.9%, 49.5%, 39.6%, and 40.0%, respectively, and these serial decreases in prevalence over 8 years were statistically significant (p<0.001). Regardless of sex, age or EGD findings, the prevalence of H. pylori infection was significantly decreased. In the analysis of the H. pylori infection-related factors in 2005, only age and EGD findings (peptic ulcer diseases) were significant factors., Conclusions: The prevalence of H. pylori infection was significantly decreased during 8-year period in Korean health check-up subjects. Age and peptic ulcer diseases were the two significant factors related to H. pylori infection in Korea.

Significant progress and new insights have been gained since Helicobacter pylori was found in 1982. Even with currently most effective treatment regimen, about 10-20% of patients will fail to obtain the eradication of H. pylori infection. This review will focus on the empirical treatment for H. pylori infection in Korea. Seven days triple therapy (proton pump inhibitor, amoxicillin and clarithromycin) has been the main first line therapy for H. pylori infection in Korea after the recommendation by Korean H. pylori study group in 1998. Such triple therapy has been the effective regimen for eradication of H. pylori infection. However, the efficacy of 7 days proton pump inhibitor-amoxicillin-clarithromycin therapy becomes lower and various eradication rates probably reflects the increase in antimicrobial resistance, recently. The recent multi-center prospective randomized study and meta-analysis showed 14 days proton pump inhibitor-amoxicillin-clarithromycin therapy is more effective than 7 days or 10 days therapy. In the case of failure, quadruple therapy (proton pump inhibitor, a bismuth salt, metronidazole and tetracycline) is a very effective second-line regimen. After the failure of two or more eradication treatments, bacterial resistance to antibiotics should be evaluated and the regimen of third-line therapy should be selected according to each antimicrobial susceptibility. The empirical third-line therapies, recommended in the cases that antimicrobial susceptibility test is unavailable, are unclear of its validity at present in Korea. The triple therapies including rifabutin, moxifloxacin, or levofloxacin or dual therapy including high dose proton pump inhibitor and amoxicillin are needed to be proven as possible candidates for the empirical third-line therapy. Multiple eradication failures should be handled on a case-by-case basis by specialists.

Background/aims: NSAIDs induce gut damage throughout the entire gastrointestinal tract and bacterial translocation. The aim of this study was to examine if administration of glutamine was able to prevent the NSAID-induced gut damages and bacterial translocation in the animal models., Methods: Rats were utilized into 5 groups; control group, diclofenac group, and diclofenac with glutamine 0.8, 1.6, and 3.2 g/kg/day group. The animals with glutamine were fed with L-glutamine for 4 days before diclofenac administration. Gut injury was induced by administration of a single dose of diclofenac (80 mg/kg orally). Intestinal permeability (24 hour urinary excretion of phenolsulfonphthalein), enteric aerobic bacterial counts, serum biochemical profiles and bacterial translocation to mesenteric lymph nodes, liver and spleen were measured., Results: Diclofenac caused the increase in intestinal permeability, enteric bacterial count, enteric protein and albumin loss and bacterial translocation. Administration of glutamine reduced the increase in intestinal permeability, protein losing enteropathy, enteric bacterial overgrowth and bacterial translocation induced by diclofenac., Conclusions: Glutamine may have beneficial effects on NSAID-induced gut damage and bacterial translocation.

Background/aims: In order to identify microsatellite instability (MSI), the test based on the polymerase chain reaction (PCR) can be used. However, PCR is not routinely performed in all hospital laboratories. Recently, immunohistochemistry (IHC) for MLH1 and MSH2 proteins has been reported as a rapid and useful method for MSI. However, the efficacy of IHC in the detection of the MSI has not been well established. The aim of this study was to evaluate the usefulness of IHC in the detection of the MSI by comparing it with the test results using PCR in colorectal cancer (CRC)., Methods: Paraffin-embedded normal and tumor tissues from seventy-five patients who underwent surgical resection of CRC were used. Abnormal expression of MLH1 and MSH2 protein was determined by IHC using MLH1 and MSH2 antibodies. Normal and tumor DNAs were obtained from thirty CRC tissues that showed abnormal expression of MLH1 and MSH2 proteins by IHC. The MSI status was confirmed by PCR using five markers., Results: Thirty tumors showed abnormal expression of MLH1 and MSH2 proteins by IHC, but only three tumors out of them were confirmed to have MSI by PCR., Conclusions: This result suggests that IHC with MLH1 and MSH2 antibodies does not seem to be a useful method to identify MSI in CRC, therefore PCR is required for detection of the MSI.

Background/aims: Migration of neutrophil across the intestinal epithelium is a structural hallmark of active intestinal diseases. One of the characteristic histologic features of Helicobacter pylori (H. pylori) infection is neutrophil infiltration of the gastric mucosa. This study was aimed to establish an in vitro model system of transepithelial migration of neutrophil by H. pylori., Methods: Caco-2 cells were grown on polycarbonate membrane. Confluence and integrity were assessed by measuring the transepithelial electrical resistance (TER) and paracellular permeability of macromolecular marker. IL-8 mRNA expression was assessed after H. pylori infection by quantitative RT-PCR. Isolated neutrophils and H. pylori were applied to the basolateral and apical compartment in separate. Also neutrophil transmigration was assessed by light and electron microscopy., Results: Paracellular leakage of 3[H]-mannitol was negligible over TER 166 Omega x cm2. IL-8 mRNA expression increased after H. pylori infection. Neutrophil transmigration was increased by adding of N-formyl-methionyl-leucyl-phenylalanine or H. pylori., Conclusions: This in vitro model system could be applied to the study of pathogenesis of H. pylori infection. A further study of quantification of transmigrated neutrophils is demanded to reach a confirmation.