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Background and aim Diabetic gastropathy is associated with loss of interstitial cells of Cajal and autonomic neuropathy. Effective management for diabetic gastropathy is still unavailable. This study was aimed to confirm the pathogenetic changes in diabetic gastropathy and to examine the effect of treatment with placental-derived mesenchymal stem cells (PDMSCs) in stomachs of animal models. Methods Fourteen non-obese diabetic/ShiLtJ mice of 8 weeks were bled until week 30. Diabetes mellitus developed in 10 out of 14 mice, which all survived with insulin. The mice were grouped into three groups: nondiabetic group (n = 4), diabetic sham group (n = 5), and diabetic PDMSC group (n = 5) all of which were treated with intraperitoneal PDMSCs injection at week 30. All mice were killed at week 34, and the stomachs were examined by immunohistochemical stain with c-kit and neuronal nitric oxide synthase antibodies. Results The number of c-kit positive cells in stomach decreased significantly in the diabetic sham group compared with that in the nondiabetic group (21.2 ± 6.7 vs 88.0 ± 29.3, P = 0.006) but increased with PDMSC treatment (21.2 ± 6.7 vs 64.0 ± 15.1, P = 0.02). The positive rate of neuronal nitric oxide synthase in neural plexus was also significantly lower in the diabetic sham group than in the nondiabetic group (22.3% ± 18.5% vs 48.0% ± 22.7%, P = 0.003) but increased with PDMSC treatment (22.3% ± 18.5% vs 43.3% ± 20.5%, P = 0.03). Conclusions Interstitial cells of Cajal and neural plexus decreased in stomachs of mice with diabetes mellitus but were significantly repaired with intraperitoneal injection of PDMSC.

Omega-3 polyunsaturated fatty acids (ω-3PUFAs) have inhibitory effects in various preclinical cancer models, but their effects in intestinal polyposis have never been examined. As attempts have been made to use nutritional intervention to counteract colon cancer development, in this study we evaluated the effects of ω-3 PUFAs on intestinal polyposis in the Apc(Min/+) mouse model. The experimental groups included wild-type C56BL/6 mice, Apc(Min/+) mice, fat-1 transgenic mice expressing an n-3 desaturase to enable ω-3 PUFA synthesis, and Apc(Min/+) × fat-1 double-transgenic mice; all mice were 20 weeks of age. Small intestines were collected for gross and pathologic evaluation, including assessment of polyp number and size, followed by immunohistochemical staining and Western blotting. After administration of various concentrations of ω-3 PUFAs, PUFA levels were measured in small intestine tissue by GC/MS/MS analysis to compare with PUFA synthesis of between C57BL6 and fat-1mice. As a result, ω-3 PUFAs significantly attenuated Apc mutation-induced intestinal polyposis accompanied with significant inhibition of Wnt/β-catenin signaling, COX-2 and PGE2, but induced significant levels of 15-PGDH. In addition, significant induction of the inflammasome-related substrates as IL-1β and IL-18 and activation of caspase-1 was observed in Apc(Min/+) × fat-1 mice. Administration of at least 3 g/60 kg ω-3 PUFAs was equivalent to ω-3 PUFAs produced in fat-1 mice and resulted in significant increase in the expression of IL-1β, caspase-3 and IL-18, as seen in Apc(Min/+) × fat-1 mice. We conclude that ω-3PUFAs can prevent intestinal polyp formation by inhibition of Wnt/β-catenin signaling, but increased levels of 15-PGDH and IL-18.

The sonic hedgehog (Shh) signaling has been known to contribute to carcinogenesis in organ, where hedgehog exerted organogenesis and in cancers, which are developed based on mutagenic inflammation. Therefore, colitis-associated cancer (CAC) can be a good model to prove whether Shh inhibitors can be applied to prevent, as the efforts to discover potent anti-inflammatory agent are active to prevent CAC. Here, under the hypothesis that Shh inhibitors can prevent CAC, mouse model was generated to develop CAC by azoxymethane (AOM)-initiated, dextran sodium sulfate-promoted carcinogenesis. Shh inhibitors, cerulenin and itraconazole were treated by oral gavage and the mice were sacrificed at early phase of 3 weeks and late phase of 16 weeks. Compared to control group, the number of aberrant crypt foci at 3 weeks and tumor incidence at 16 weeks were all significantly decreased with Shh inhibitor. Significant attenuations of macrophage infiltration accompanied with significant decreases of IL-6, COX-2, STAT3 and NF-κB as well as significant ameliorations of β-catenin nuclear translocation, cyclin D1 and CDK4 were imposed with Shh inhibitors. Especially, CAC was accompanied with significant cancellation of 15-hydroxyprostaglandin dehydrogenase (15-PGDH), but their levels were significantly preserved with Shh inhibitors. Among inflammatory mediators, significantly decreased levels of IL-6 and TNF-α, regulated with repressed NF-κb and STAT3, were prominent with Shh inhibitor, whereas significant inductions of apoptosis were noted with Shh inhibitors. In conclusion, Shh inhibitors significantly prevented CAC covering either ameliorating oncogenic inflammation or suppressing tumor proliferation, especially supported with significant inhibition of IL-6 and STAT3 signaling, 15-PGDH preservation and apoptosis induction.

Background and Aim Nonsteroidal anti-inflammatory drugs (NSAIDs), the most highly prescribed drugs in the world for the treatment of pain, inflammation, and fever, are associated with gastric mucosal damages including ulcer directly or indirectly. This study was aimed to document the preventive effects of an organosulfur constituent of garlic, S-allyl cysteine (SAC), against NSAIDs-induced gastric damages, as well the elucidation of its pharmacological actions, such as anti-inflammatory, anti-oxidative, and cytoprotective actions. Methods Different doses of SAC were administrated intragastrically before the indomethacin administration. After killing, in addition to gross and pathological evaluations of ulcer, the expressions of inflammatory mediators, including cyclooxygenase-2, prostaglandin E2, IL-1β, tumor necrosis factor-α, IL-6, and anti-oxidant capacity, were analyzed by Western blot analysis or ELISA, respectively. Transferase deoxytidyl uridine end labeling assay, periodic acid and Schiff staining, F4/80 staining, and CD31 staining were compared among doses of SAC. Detailed documentation of in vitro biological actions of SAC, including NF-κB, histone deacetylator inhibition, phase 2 enzyme, and MAPKs, was performed. Results SAC was very effective in preventing indomethacin-induced gastric damages in a low dose through significant decreases in macrophage infiltration as well as restorative action. Indomethacin-induced expressions of inflammatory mediators were all significantly attenuated with SAC in accordance with histone deacetylator inhibition. In addition, SAC significantly increased the total anti-oxidant concentration and mucus secretion, and allows for a significant induction of HO-1. However, these preventive effects of SAC were dependent on dosage of SAC; higher dose above 10 μM paradoxically aggravated NSAID-induced inflammation. Conclusion Synthetic SAC can be promising therapeutics agent to provide potent anti-inflammatory, anti-oxidative, and mucosa protective effects against NSAID-induced damages.

Objective No distinctive biomarkers capable of discriminating between ulcerative colitis (UC) and Crohn's disease (CD) have yet been found. In this study, we aimed to discover these biomarkers by using advanced label-free quantification technology for proteomes. Methods Biomarker protein expressions of colonic tissues of Korean IBD patients and controls were determined using label-free quantification to compare the protein profiles of colonic mucosa in three individuals with normal colonic tissue, four patients with UC, three with CD and two with inflammatory polyps related to UC. A computational framework and tools for discovery-based liquid chromatography-tandem mass spectrometry proteomics was applied to draw the biomarkers. Results In total, 339 proteins were identified in normal sample group, 217 and 283 proteins in active and inactive UC, 345 and 366 proteins in active and inactive CD and 392 proteins in inflammatory polyps related to UC, respectively. The findings were reproducible. A Corra analysis led to the discovery of 27 potential biomarkers in UC, 37 biomarkers relevant to CD and 11 proteins commonly associated with IBD. Three novel proteins, PRG2, LCP1 and PSME1 were identified as biomarkers signifying active CD. Conclusion This is the first study to apply label-free quantification for discovering biomarkers in patients with different types and stages of IBD, providing additional insights for revealing the molecular pathogenesis of IBD as well as protein biomarkers of IBD predicting responses to treatment.

Background and Aim Increased resistance of Helicobacter pylori to antibiotics has increased the need to develop new first-line treatments for H. pylori. We have prospectively evaluated 10-day sequential versus conventional triple therapy in peptic ulcer patients. Methods One hundred and fifty-nine patients with peptic ulcer diseases were prospectively randomized to receive 10 days of lansoprazole, amoxicillin, and clarithromycin (conventional triple therapy) or 5 days of lansoprazole and amoxicillin followed by 5 days of lansoprazole, clarithromycin, and metronidazole (sequential therapy). Post-treatment H. pylori status was determined by the 13C-urea breath test. Eradication rates, antibiotic resistance rates by agar dilution method, drug compliance, and side-effects were compared. Results The intention-to-treat eradication rates were 75.9% (95% CI 66.5–85.3%, 60/79) in the sequential therapy group and 58.7% (95% CI 47.9–69.5%, 47/80) in the conventional triple therapy group (P = 0.01), while the per-protocol eradication rates were 86.8% (95% CI 78.7–94.8%, 59/68) and 67.6% (95% CI 56.5–78.7%, 46/68) (P = 0.01), respectively. Compliance and side-effects were similar in the two groups. Culture of H. pylori showed that 18.2% were resistant to clarithromycin, 41.9% to metronidazole. Dual resistance to both antibiotics was 9.6%. Conclusions Although 10-day sequential therapy yielded a higher H. pylori eradication rate than 10-day conventional triple therapy, the sequential therapy protocol did not result in a sufficiently satisfactory eradication rate. This might be related to the higher antibiotics resistance rate especially to dual resistance. More effective regimens are needed to overcome antibiotic resistance in Korea.

Proteomics offers considerable opportunities for either enhancing our biological understanding or discovering biomarkers, blood and biopsied specimen-based proteomic approaches, provide reproducible and quantitative tools that can complement clinical assessments and aid clinicians in the diagnosis and treatment of inflammatory bowel disease (IBD). Sometimes a differential diagnosis of Crohn's disease (CD) and ulcerative colitis (UC) and the prediction of treatment response can be deduced by finding meaningful biomarkers, for which the central platform for proteomics is tandem mass spectrometry (MS/MS). A range of workflows are available for protein (or peptide) separation prior to MS/MS as well as bioinformatics analysis to achieve protein identification, for which two-dimensional electrophoresis (2-DE) and subsequent mass spectrometry (MS), liquid chromatography-MS, difference gel electrophoresis following 2-DE, isobaric tags for relative and absolute quantification (iTRAQ), stable isotope labeling by amino acids and label-free quantification are under development. In this article, the current status and perspective of these advanced proteomic technologies are introduced, with examples of recent biomarkers focused on the diagnosis, treatment response, prognosis of IBD, and even colitis-associated carcinogenesis in both animal models and human patients.

Oxygen free radicals in excessively high amounts are all very reactive chemically and can impose a detrimental influence on living organisms by provoking “oxidative stress” that can damage major cellular constituents. The latter includes the cell membrane, cytoplasmic proteins, and nuclear DNA. Conversely, nitric oxide (NO), superoxide anion, and related reactive oxygen species (ROS) when present in low amounts play an important role as regulatory mediators in signaling processes, through which, paradoxically, many ROS-mediated responses can protect the cells against oxidative stress by induction of “redox homeostasis.” Therefore, diseases associated with free radical overproduction are provoked by “blazed ROS productions” far beyond the host's capacity to quench. Free radicals have been implicated in the pathogenesis of diverse gastrointestinal (GI) diseases including gastroesophageal reflux disease (GERD), gastritis, enteritis, colitis and associated cancers as well as pancreatitis and liver cirrhosis. This article provides an overview of the role of oxidative stress in inflammation-based GI tract diseases, including reflux esophagitis, Helicobacter pylori-associated gastritis, non-steroidal anti-inflammatory drug-induced enteritis, ulcerative colitis, and associated colorectal cancer. The challenging issue that ROS can contribute to diverse gastrointestinal dysfunction, or manifest dual roles in cancer promotion or cancer suppression will also be discussed for the opportunity to enhance understanding of inflammation-based GI diseases.

Background and Aim: Cysteamine is a reducing aminothiol used for inducing duodenal ulcer through mechanisms of oxidative stress related to thiol-derived H2O2 reaction. Cochinchina momordica saponins have been suggested to be protective against various gastric diseases based on their cytoprotective and anti-inflammatory mechanisms. This study was aimed to document the preventive effects of Cochinchina momordica seed extract against cysteamine-induced duodenal ulcer as well as the elucidation of its pharmacological mechanisms. Methods: Cochinchina momordica seed extract (50, 100, 200 mg/kg) was administrated intragastrically before cysteamine administration, after which the incidence of the duodenal ulcer, ulcer size, serum gastrin level, and the ratio of reduced glutathione (GSH)/ oxidized glutathione disulfide (GSSG) as well as biochemical and molecular measurements of cytoplasmic phospholipase A2 (cPLA2), cyclooxygenase-2 (COX-2), 5-lipoxygenase and the expression of proinflammatory genes including IL-1β, IL-6, COX-2 were measured in rat model. Additional experiments of electron spin resonance measurement and the changes of glutathione were performed. Results: Cochinchina momordica seed extract effectively prevented cysteamine-induced duodenal ulcer in a dose-dependent manner as reflected with significant decreases in either duodenal ulcerogenesis or perforation accompanied with significantly decreased in serum gastrin in addition to inflammatory mediators including cPLA2, COX-2, and 5-lipoxygenase. Cochinchina momordica seed extract induced the expression of γ-glutamylcysteine synthetase (γ-GCS)-related glutathione synthesis as well as significantly reduced the expression of cPLA2. Cochinchina momordica seed extract preserved reduced glutathione through increased expressions of γ-GCS. Conclusion: Cochinchina momordica seed extracts exerted significantly protective effect against cysteamine-induced duodenal ulcer by either cPLA2 inhibition or glutathione preservation.

Background and Aim: The term “stress-related mucosal disease” (SRMD) represents conditions ranging from superficial mucosal damage to focal deep mucosal damage in the stomach, of which pathogenesis is deduced to be violent mucosal ischemia or excess oxidative stress, but not fully clarified yet. Under the hypothesis that mucosal cell apoptosis subsequent to endoplasmic reticulum (ER) stress might play a crucial role, we evaluated the efficacy and mechanism that novel acid pump antagonist (APA), revaprazan, alleviated water immersion restraint stress (WIRS) induced SRMD in rats. Methods: In order to define whether WIRS-induced SRMD is associated with ER stress, we checked the alteration in the expression of ER stress markers including GRP78, CHOP, XBP-1, BiP as well as apoptosis in WIRS-induced SRMD. The efficacy of revaprazan on either alleviating ER stress or attenuating SRMD was compared with proton pump inhibitor (PPI) and gastroprotectant. Results: Ten hours of WIRS induced a severe degree of SRMD, in which ER stress markers including CHOP, XBP1, and BiP were significantly overexpressed in the gastric tissues. However, these markers of ER stress were significantly decreased in the group pretreated with revaprazan compared to PPI or gastroprotectant, accompanied with a significant reduction in apoptotic index. In addition to ER stress, revaprazan imposed anti-inflammatory benefit to limit SRMD based on significant levels of inflammatory cell apoptosis. Conclusion: Endoplasmic reticulum stress accompanied with drastic apoptosis was implicated in the development of SRMD, but revaprazan could rescue the stomach from SRMD through alleviating ER stress in epithelial cells much better than either PPI or gastroprotectant.

While dietary habits or nutritional intake continue to rank as significant factors influencing the incidence of cancer, there have been considerable scientific uncertainties about who will benefit, but who about will not benefit from nutrition. This might be due to inadequate knowledge about an individual's genetic background, the cumulative effect of nutrients on genetic expression profiles, ambiguous clinical differences between beneficiaries and non-beneficiaries and the lack of information about active protein induction. During the past 200 years of nutrition research, we have experienced revolutionary advances in both chemistry and genomics. According to the high expectations for tailored medicine, a nutrigenomic approach harboring tremendous potential to change the future of dietary guideline and personal recommendations will provide an essential basis for personalized dietary recommendations to prevent common multifactorial diseases decades before their overt clinical manifestation. In the current review, we introduce our efforts to discover Helicobacter pylori (H. pylori)-related disease biomarkers applicable for diagnostic, predictive and therapeutic purposes using several kinds of technology. For instance, based on publications showing the in vitro and in vivo efficacy of Korean red ginseng on mitigating H. pylori-associated gastric atrophy, a nutrigenomic approach allows us to confirm that Korean red ginseng prevents H. pylori-associated gastric cancer in predictable ways.

Background and Aims: The cytokine interleukin (IL)-27 is composed of two subunits, Epstein–Barr virus-induced gene 3 (EBI3) and p28, and IL-27 is a novel IL-12 family member that mediates between the innate and adaptive immune systems. We previously identified four polymorphisms in the human IL-27 gene and we suggested that the polymorphism of IL-27 is associated with the susceptibility to asthma. IL-27 transcripts are significantly elevated in active Crohn's disease (CD) but not in ulcerative colitis (UC). To determine whether these IL-27 single nucleotide polymorphisms are associated with the susceptibility to inflammatory bowel disease (IBD), the genotype and allelic frequencies of the IL-27 polymorphisms were analyzed between the IBD patients and the healthy controls. Methods: Genotype analysis of the IL-27 gene was performed by the single-base extension (SBE) method. The haplotype frequencies of IL-27 for multiple loci were estimated using the expectation maximization (EM) algorithm. Results: The genotype frequencies of the g.-964A > G polymorphism in the IBD patients were significantly different from those of the healthy control group (P = 0.001). In both the UC and CD patients, the genotype frequencies of the g.-964A > G polymorphism were also significantly different from the frequencies of the healthy control group (P = 0.009). The frequencies of the AGT and GGT haplotypes were significantly different between the healthy control group and the IBD patient group (P = 0.00004 and 0.021, respectively). Conclusion: Our results suggest that the g.-964A > G polymorphism of the IL-27 gene located on the IBD1 locus might be associated with the susceptibility to IBD.

Although data mining and knowledge discovery techniques have recently been used to diagnose human disease, little research has been conducted on disease diagnostic modelling using human gene information. Furthermore, to our knowledge, no study has reported on diagnosis models using single nucleotide polymorphism (SNP) information. A disease diagnosis model using data mining techniques and SNP information should prove promising from a practical perspective as more information on human genes becomes available. Data mining and knowledge discovery techniques can be put to practical use detecting human disease, since a haplotype analysis using high-density SNP markers has gained great attention for evaluating human genes related to various human diseases. This paper explores how data mining and knowledge discovery can be applied to medical informatics using human gene information. As an example, we applied case-based reasoning to a cancer detection problem using human gene information and SNP analysis because case-based reasoning has been applied in medicine relatively less often than other data mining techniques. We propose a modified case-based reasoning method that is appropriate for associated categorical variables to use in detecting gastric cancer.

Background: Quality of life (QOL) in patients with functional dyspepsia in South Korea has never been studied, mostly due to the lack of a psychometrically validated disease-specific instrument for measuring the QOL. The aim of the present study was to develop and validate a QOL scale for patients with functional dyspepsia. Methods: A Functional Dyspepsia-Related QOL (FD-QOL) scale was developed and validated as follows: item generation, pilot test, and psychometric test. Patients with functional dyspepsia (n = 220) were recruited from seven university hospitals. The participants were asked to complete the preliminary item-generated FD-QOL, the Short Form-36 (SF-36), and the Index of Dyspepsia Symptoms-Korean (IDS-K). The data were analyzed using factor analysis, correlation, anova, and Cronbach’s alpha. Results: Twenty-three items were generated based upon content validity. Factor analysis extracted a four-factor solution, and two items were deleted because they were not loaded significantly on any factor. The FD-QOL was correlated with the SF-36 subscales, of which scores were differentiated according to the levels of dyspepsia symptoms. Cronbach’s alpha of the FD-QOL was 0.94. Conclusions: The FD-QOL scale is a rapid and easily applicable instrument with excellent psychometric properties of content, factorial, convergent, and known-groups validity, and internal consistency reliability in Korean patients with functional dyspepsia.

Background: It has been suggested that chronic, persistent, uncontrolled inflammations in the stomach could provide the basic step for the beginning of carcinogenesis. One of the potential clinical applications of rebamipide is the inhibition of the immuno-inflammatory response in gastric mucosa imposed by Helicobacter pylori. Aim: To determine the implications of long-term rebamipide treatment in H. pylori infection, we studied the underlying moleculo-pathological changes in gastric lesions in mice infected with H. pylori (SS1 strain), following this treatment. Methods: C57BL/6 mice were sacrificed 24 and 50 weeks after H. pylori infection, respectively. Colonization rates of H. pylori, degree of gastric inflammation and other pathological changes including atrophic gastritis and metaplasia, serum levels of IL-1β, TNF-α, IFN-γ and IL-10, mRNA transcripts of various mouse cytokines and chemokines, and NF-KB binding activities, and finally the presence of gastric adenocarcinoma were compared between an H. pylori infected group (HP), and an H. pylori infected group administered with long-term rebamipide-containing pellet diets (HPR). Results: Serum levels of IL-1β, IFN-γ and TNF-α, the gastric mucosal expression of ICAM-1, HCAM and MMP, and transcriptional regulation of NF-KB-DNA binding were all significantly decreased in the HPR group compared with the HP group. An RNase protection assay showed, in the rebamipide administered group, significantly decreased mRNA levels of apoptosis-related genes such as caspase-8, FasL, Fas, TRAIL and various cytokines genes such as IFN-y, RANTES, TNF-A, TNFR p75. IL-1β. In the experiment designed to provoke gastric cancer through MNU treatment with H. pylori infection, the incidence of gastric carcinoma was not different in either group. However, long-term administration of rebamipide showed the advantage of decreasing precancerous lesions like chronic atrophic gastritis and showed molecular evidence of attenuation of proliferation. Conclusion: The long-term administration of rebamipide should be considered in the treatment of H. pylori since it demonstrated molecular and biological advantages like a lessening of gastric inflammation and a possible chemopreventive effect.

Background: Long-term evaluation of gastric pathology after H. pylori infection is very important in order to reveal its clinical implications, since debate still exists on the gastric carcinogenesis provoked by H. pylori infection in animal models. Aim: Either to evaluate the long-term outcome of H. pylori infection or to determine how H. pylori could provoke gastric cancer in the mice model. Methods: Four-week-old specific pathogen free C57BL/6 mice (n = 115) were infected with SS1. the mouse-adapted H. pylori strain. After 4, 8, 16, 24, 36, 50 and 80 weeks of bacterial infection, the H. pylori-infected mice were sacrificed. Results: After 80 weeks of infection, almost all the H. pylori-infected mice developed hyperplastic gastritis. but did not show any evidence of gastric adenoma, dysplasia or carcinoma. PCNA positive cells were most abundant after 50 weeks and tended to decrease thereafter up to 80 weeks, whereas apoptosis began to be noted 8 weeks after H. pylori infection, showing 7-8 apoptotic cells/high power field, and tending to increase as time passed. Normally observed neutral mucin decreased during the experiment, showing the most marked decrease 50 weeks after H. pylori infection. In contrast, acidic mucin was noted from 50 weeks after infection. Conclusion: The SS1-infected mouse seems to be a suitable animal model for H. pylori-related research. and H. pylori itself does not induce gastric cancer in normal wild-type mouse model following long-term exposure, which could be explained by the balance that exists between cell proliferation and apoptosis.

Background: Downregulation of TGF-β receptors is implicated in colon cancer development. Inactivation of either of the two transmembrane serine/threonine kinases, TGF-β1 types I/II receptors, is now implicated in carcinogenesis, especially gastrointestinal carcinogenesis. Methods: We generated transgenic mice, called pS2–dnRII or ITF–dnRII, of which the dominant negative mutant of the TGF-β type II receptor was expressed under the control of tissue-specific promoters, the pS2 promoter for stomach and ITF for intestine. They were either infected with H.pylori (ATCC 43504 strain, CagA+ and VacA+) or administered with azoxymethane to determine the significance of loss of TGF-β signalling in gastrointestinal carcinogenesis. Results: Gastric adenocarcinoma developed in pS2–dnRII mice, whereas only chronic active gastritis was noted in wild-type littermates after 36 weeks of H.pylori infection. Mice lacking in TGF-β signalling specifically in the stomach showed a significantly higher proliferation cell nuclear antigen-labelling index when infected with H.pylori than wild-type littermates (P

Background and Aim: Debate that Helicobacter pylori might play a causative role in gastric carcinogenesis still exists in spite of the World Health Organization’s definition of H. pylori as a class I carcinogen. In order to define the exact role of H. pylori infection in gastric carcinogenesis, we established a mice model of H. pylori infection. Methods: One hundred and forty-four female C57BL/6 mice were divided into nine groups according to N-methyl-N-nitrosourea (MNU) treatment and H. pylori infection. All mice were killed at the 50th or 80th week after treatment, and their histopathological changes were evaluated according to group. Results: The incidence of gastric adenocarcinoma at the 50th week was 80% in mice treated with both MNU 240 μg/L and H. pylori infection, whereas the incidence was only 27% in mice treated with only MNU 240 μg/L. Although H. pylori caused marked expansion of the proliferative zone at the surface epithelium, H. pylori infection alone caused only chronic atrophic gastritis without any evidence of carcinomas until 80 weeks. The combination of MNU and H. pylori infection also resulted in a significantly higher incidence of gastric adenoma and adenocarcinoma. Significantly higher expressions of proliferating cell nuclear antigen were noted in the gastric mucosa infected with H. pylori compared to controls. Conclusions: These results clearly demonstrated the role of H. pylori infection, rather than direct carcinogens, in promoting gastric carcinogenesis in a mice model. © 2002 Blackwell Science Asia Pty Ltd

Background: Arachidonic acid metabolites have been considered as pivotal mediators in Helicobacter pylori-induced inflammatory response, which are mainly metabolized by two distinct enzymes: cyclooxygenase (COX) and lipoxygenase (LOX). While COX has become well known to play a key role in either carcinogenesis or inflammation related to H. pylori infection, little is known regarding the implication of LOX in H. pylori infection. In this study, we evaluated the roles of 5-LOX and its metabolites in H. pylori-induced host responses and further a potential beneficial action of specific LOX inhibitors against H. pylori infection. Materials and Methods: Expressions of cytosolic phospholipase A2 (cPLA2), COX-2, and 5-LOX after H. pylori infection were evaluated by immunofluorescence staining and Western blotting. Synthesis of LOX metabolites was measured with reversed-phase high-performance liquid chromatography. For analyzing the influence of 5-LOX inhibitors, nordihydroguaiaretic acid (NDGA) and geraniin, on H. pylori-induced inflammatory responses, RNase protection assay and RT-PCR were performed. Results: H. pylori stimulated the translocation of cPLA2 from cytoplasm to nucleus and increased the biosynthesis of hydroxyeicosatetraenoic acids (HETEs) as a predominant form of 5S-HETE in gastric epithelium. NDGA exerted a strong suppression activity of H. pylori-induced 5-LOX signaling. The administration of LOX inhibitors was related with down-expression of proinflammatory mediators such as interleukin-8 and tumor necrosis factor-α in both H. pylori-infected gastric epithelial cells and macrophage cells. Conclusion: LOX modulation with its specific inhibitors could impose significant anti-inflammatory responses after H. pylori infection, based on the fact that H. pylori infection provoked gastric inflammation through metabolizing arachidonic acid by the 5-LOX pathway.