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High-mobility group box 1 (HMGB1) was initially discovered as a nuclear protein that interacts with DNA as a chromatin-associated non-histone protein to stabilize nucleosomes and to regulate the transcription of many genes in the nucleus. Once leaked or actively secreted into the extracellular environment, HMGB1 activates inflammatory pathways by stimulating multiple receptors, including Toll-like receptor (TLR) 2, TLR4, and receptor for advanced glycation end products (RAGE), leading to tissue injury. Although HMGB1's ability to induce inflammation has been well documented, no studies have examined the role of HMGB1 in wound healing in the gastrointestinal field. The aim of this study was to evaluate the role of HMGB1 and its receptors in the healing of gastric ulcers. We also investigated which receptor among TLR2, TLR4, or RAGE mediates HMGB1's effects on ulcer healing. Gastric ulcers were induced by serosal application of acetic acid in mice, and gastric tissues were processed for further evaluation. The induction of ulcer increased the immunohistochemical staining of cytoplasmic HMGB1 and elevated serum HMGB1 levels. Ulcer size, myeloperoxidase (MPO) activity, and the expression of tumor necrosis factor α (TNFα) mRNA peaked on day 4. Intraperitoneal administration of HMGB1 delayed ulcer healing and elevated MPO activity and TNFα expression. In contrast, administration of anti-HMGB1 antibody promoted ulcer healing and reduced MPO activity and TNFα expression. TLR4 and RAGE deficiency enhanced ulcer healing and reduced the level of TNFα, whereas ulcer healing in TLR2 knockout (KO) mice was similar to that in wild-type mice. In TLR4 KO and RAGE KO mice, exogenous HMGB1 did not affect ulcer healing and TNFα expression. Thus, we showed that HMGB1 is a complicating factor in the gastric ulcer healing process, which acts through TLR4 and RAGE to induce excessive inflammatory responses.

Background and Aims: Cytoglobin (Cygb) is the newest globin family and is upregulated during hypoxia to maintain the oxygen status. Herein, we investigated Cygb expression in both acute and chronic gastric mucosal injuries., Methods: Acute gastric mucosal injuries in rats were produced by oral administration of indomethacin, followed by sacrifice at 1, 3, 6, 24, and 48 h. Gastric ulcer was produced by acetic acid, followed by sacrifice on days 3, 7, 11, 18, and 25. Each protein expression of Cygb and hypoxia-inducible factor (HIF)-1α was evaluated by western blotting. We measured vascular endothelial growth factor (VEGF) mRNA by RT-PCR and examined localization of Cygb by immunofluorescence., Results: In indomethacin-induced injury, Cygb protein was significantly increased at 24 h. In ulcerated tissues, HIF-1α protein was significantly increased on days 7 and 11 (1.83 ± 0.11 and 2.12 ± 0.19 folds, respectively, p < 0.05 and 0.01), which corresponded to the early healing phase. In contrast, Cygb protein was significantly increased on days 11 and 18 (1.87 ± 0.13 and 1.60 ± 0.06 folds, respectively, p < 0.05), which demonstrated late phase. Though these proteins peaked on day 11, VEGF mRNA was gradually increased from day 11 to 18. Cygb was expressed in fibroblasts and myofibroblasts in both acute and chronic models. Cygb and HIF-1α were abundantly colocalized at the ulcer margin before angiogenesis development. However, faint localization was observed with angiogenesis., Conclusions: Cygb may be involved in the healing process of gastric mucosal injuries in the late phase without angiogenesis.

Background and Aims: According to reports in Japanese patients, 1 week of Helicobacter pylori eradication therapy alone is not adequate for healing of gastric ulcers; 7-8 weeks of anti-ulcer therapy are subsequently required. We compared a gastroprotective drug, sofalcone, and an H(2)-receptor antagonist, cimetidine, in terms of promoting ulcer healing after 7 weeks of administration following 1 week of eradication therapy., Methods: Eradication therapy was administered to 64 patients with H. pylori-positive active gastric ulcer at least 10 mm in diameter, after which 32 patients each received 7 weeks of ulcer treatment with sofalcone (300 mg/day) or cimetidine (800 mg/day)., Results: The H. pylori eradication rate was 81.3% (intention-to-treat: ITT) and 81.3% (per protocol: PP) in the sofalcone group, and 62.5% (ITT) and 64.5% (PP) in the cimetidine group. The ulcer healing rate after 8 weeks was 71.9% (ITT) and 71.9% (PP) in the sofalcone group, and 71.9% (ITT) and 71.0% (PP) in the cimetidine group. The rate of a flat pattern of scarred mucosa was 43.5% (ITT) and 43.5% (PP) in the sofalcone group, and 47.8% (ITT) and 50.0% (PP) in the cimetidine group. No significant differences were seen between the two groups in terms of H. pylori eradication rate, ulcer healing rate and flat pattern rate., Conclusion: Sofalcone promoted gastric ulcer healing during 7 weeks of treatment following 1 week of eradication therapy, and the healing rate was equivalent to that of cimetidine. Symptom disappearance rates were significantly better in the sofalcone group than in the cimetidine group. This may be a useful way of using a gastroprotective drug in the H. pylori era.

Background: Helicobacter pylori (H. pylori) is associated with chronic gastritis and gastric carcinogenesis. The effects of nonsteroidal anti-inflammatory drugs (NSAIDs), which exert chemopreventive effects on several cancers, on H. pylori-induced gastritis remain unknown. We investigated the effects of NSAIDs on gastric inflammation and the kinetics of gastric epithelial cells in H. pylori-induced gastritis., Methods: Patients with rheumatoid arthritis or osteoarthritis who took NSAIDs for more than 1 month and complained of dyspeptic symptoms were recruited for this study. Patients not on any NSAIDs were included as non-NSAID user controls. All patients underwent diagnostic testing for H. pylori infection, esophagogastroduodenoscopy, and gastric biopsies. Neutrophil infiltration into gastric mucosa, expression of inducible nitric oxide synthase (iNOS), and apoptosis and proliferation of gastric epithelial cells were evaluated by immunohistochemistry. In an in vitro study, the effects of NSAIDs on production of interleukin (IL)-8 induced by H. pylori in a gastric epithelial cell line (AGS) were determined., Results: Numbers of neutrophils infiltrating the gastric mucosa, iNOS-expressing inflammatory cells and apoptotic cells, and proliferating cells in gastric epithelium were higher in H. pylori-positive groups than H. pylori-negative groups. Among H. pyloripositive groups, these parameters were lower in NSAID users than in non-NSAID users. NSAIDs inhibited the production of IL-8 induced by H. pylori in AGS cells., Conclusions: These findings suggest that long-term use of NSAIDs normalizes the kinetics of gastric epithelial cells in patients with H. pylori infection by attenuating gastric mucosal inflammation, which may result in prevention of the gastric carcinogenesis associated with H. pylori infection.

NSAIDs compromise gastroduodenal defense mechanism mediated by inhibiting cyclooxygenase and leading to leukocyte infiltration or neutrophil adherence, and cause gastric ulcers. There are a number of mucoprotective drugs in Japan, and they were often used for NSAIDs-induced ulcer treatment. In vitro or in vivo studies, some mucoprotective drugs have been shown to have anti-inflammatory action due to the inhibition of leukocyte infiltration, production of inflammatory cytokines. However, mucoprotective drugs were given a low priority in "the Japanese guideline for the management of gastric ulcer" edited in 2003. Therefore, mucoprotective drugs should be investigated in terms of effects on NSAIDs-induced gastric ulcer patients because there are a few reliable evidences for the treatment of NSAID-induced gastric ulcer in Japan.

Pravastatin, an HMG-CoA reductase inhibitor, exerts anti-inflammatory effects via several mechanisms including induction of endothelial nitric oxide synthase (eNOS). We investigated the effect of pravastatin on Helicobacter pylori-induced gastritis in mice. Mice with or without H. pylori infection received intraperitoneal pravastatin daily for 1 week. Expression of eNOS mRNA and tumor necrosis factor-alpha mRNA and myeloperoxidase activity in gastric tissue was determined. Myeloperoxidase activity was reduced in a dose-dependent manner by pravastatin, with activity inhibited by 53.5 and 73.7% at doses of 0.3 and 1 mg/kg, respectively. At a dose of 1 mg/kg, pravastatin reduced the level of tumor necrosis factor-alpha mRNA by 52.7%, while it did not affect eNOS expression. Pravastatin had no effects on these inflammatory parameters in uninfected mice. Pravastatin did not affect the viability of H. pylori. In conclusion, pravastatin exerts an anti-inflammatory effect on H. pylori-induced gastritis in mice without affecting eNOS expression.

Growth factors upregulate cyclooxygenase-2 (COX-2) expression and extracellular signal-regulated kinase (ERK) activity, yet little is known regarding the interaction between COX-2 and ERK in terms of mitogenic signal transduction pathways in gastric epithelial cells. Therefore, we examined the role of COX-2 in EGF-induced proliferation of gastric epithelial RGM1 cells. EGF treatment significantly induced ERK activity (peaked at 30 min) and significantly increased COX-2 protein (peaked at 6 hr), production of prostaglandin E2 (PGE2), and cell proliferation. MEK inhibitor (PD98059) decreased ERK activity and cell proliferation induced by EGF. The selective COX-2 inhibitor (NS-398) significantly reduced EGF-induced cell proliferation. Exogenous PGE2 partly reversed the NS-398-induced inhibitory action on cell proliferation, clearly indicating the importance of PGE2 in mitogenic pathway. The induction of COX-2 protein by EGF was completely blocked by preincubation with MEK inhibitor. These results suggest that the ERK-COX-2 pathway is critical for EGF-induced proliferation of gastric epithelial cells.

Background/aims: A possibility that the eradication therapy not only eliminates Helicobacter pylori (H. pylori) but also influences some factors regulating pathological changes in the gastric mucosa should be taken into consideration from some phenomena. Such as non-recurrent cases of peptic ulcer long-term in spite of unsuccessful anti-H. pylori eradication therapy and the effectiveness of eradication therapy for mucosa-associated lymphoid tissue with a low-grade malignancy except stomach. We hypothesized and investigated that antibiotic treatment for elimination of H. pylori might directly affect inflammatory cells to induce apoptosis in them and protect against pathological changes of gastric mucosa., Methodology: Subjects consisted of twenty-one patients with chronic gastritis. All were H. pylori positive and we investigated the effects of eradication therapy of H. pylori on inflammation-related immunocytes in the gastric mucosa of patients with chronic gastritis caused by H. pylori isolated mononuclear leukocytes which were taken from the patients and were examined for apoptosis-related morphological changes and DNA fragmentation before and after the therapy. Eradication therapy of H. pylori was performed by lansoprazole 30 mg/day, amoxicillin 1500 mg/day and clarithromycin 400 mg/day for one week., Results: After the H. pylori eradication therapy, regardless of its effect on H. pylori status, marked vacuolation and degeneration were observed in mononuclear leukocytes in the gastric mucosa with a concomitant enhancement of nuclear DNA fragmentation., Conclusions: This observation suggests that H. pylori eradication therapy itself induces apoptosis in mononuclear leukocytes in the gastric mucosa.

Increased expression of inducible nitric oxide synthase (iNOS) has been reported in gastric mucosa of patients with Helicobacter pylori infection or portal hypertensive gastropathy (PHG) but whether there is an additive or synergistic impact between H. pylori and PHG on iNOS expression was unknown. Sixty cirrhotic patients and 21 age-matched control subjects without liver disease were included. Biopsies from the gastric antrum and body were obtained for quantitative histological assessment and immunohistochemical staining for iNOS. iNOS staining was detected in endothelial cells and macrophages. In the absence of PHG, H. pylori significantly induced iNOS expression in cirrhotic patients. PHG also significantly induced iNOS expression in H. pylori-negative patients. However, there was no synergistic or additive effect between H. pylori and PHG on this expression. Furthermore, expression of iNOS was significantly higher in patients with severe PHG than in those with mild PHG and without PHG.

Background: The necessity of additional gastrectomy for patients not meeting the inclusion criteria after endoscopic submu cosal dissection (ESD) is controversial. The aim of this study was to elucidate the risk factors for lymph node metastasis (LNM) and residual cancer (RC) in patients not meeting the inclusion criteria after ESD and to determine additional treatment strategies.Methods: Of 1443 gastric cancer patients who underwent ESD between 2004 and 2013, 167 patients diagnosed as having a lesion not meeting the inclusion criteria after ESD were retrospectively analyzed. Of the 167 cases, 100 cases underwent additional gastrectomy, and 67 cases were observed without surgery.Results: Overall, 9.0 % (9/100) and 9.0 % (9/100) of patients not meeting the inclusion criteria after ESD presented with LNM and RC, respectively, but neither was observed in 83 patients (83.0 %). Multivariate analysis revealed that lymphovascular involvement (LVI) (OR 38.38; 95 % CI 1.94-761.43, p = 0.017) and undifferentiated type (OR 45.58; 95 % CI 2.88-720.94, p = 0.007) were independent risk factors for LNM, and positive horizontal margin was an independent risk factor for RC (OR 9.48; 95 % CI 1.72-52.13, p = 0.010). In differentiated types without LVI, no cases had LNM (0/38) in the additional gastrectomy group, and there was no lymph node or distant recurrence (0/39) in the observation group.Conclusions: Additional treatment is necessary for patients with LVI, undifferentiated type, and positive horizontal margin. Careful follow-up may be acceptable for patients with the differentiated type without LVI, especially for the elderly or patients with severe comorbidities. [ABSTRACT FROM AUTHOR]

Neutrophil infiltration mediated by TNF-α is associated with various types of gastric injury, whereas PGs play a crucial role in gastric defense. We examined roles of two isoforms of cyclooxygenase (COX) and PGE[sub 2] in Helicobacter pylori-induced gastritis in mice. Mice infected with H. pylori were given selective COX-1 inhibitor SC-560 (10 mg/kg), selective COX-2 inhibitor NS-398 (10 mg/kg), or nonselective COX inhibitor indomethacin (2 mg/kg) with or without 16,16-dimethyl PGE[sub 2] for 1 wk. H. pylori infection increased levels of mRNA for COX-1 and -2 in gastric tissue by 1.2-fold and 3.3-fold, respectively, accompanied by a significant increase in PGE2 production by gastric tissue. H. pylori infection significantly elevated MPO activity, a marker of neutrophil infiltration, and epithelial cell apoptosis in the stomach. SC-560 augmented MPO activity and epithelial cell apoptosis with associated reduction in PGE[sub 2] production, whereas NS-398 had the same effects without affecting PGE2 production. Inhibition of both COX-1 and -2 by indomethacin or concurrent treatment with SC-560 and NS-398 resulted in a stronger increase in MPO activity and apoptosis than inhibition of either COX-1 or -2 alone. H. pylori infection elevated TNF-α mRNA expression in the stomach, which was further increased by indomethacin. Effects of COX inhibitors on neutrophil infiltration, apoptosis, and TNF-α expression in H. pylori-infected mice were abolished by exogenous 16,16-dimethyl PGE[sub 2]. In conclusion, PGE[sub 2] derived from either COX-1 or -2 is involved in regulation of gastric mucosal inflammation and contributes to maintenance of mucosal integrity during H. pylori infection via inhibition of TNF-α expression. neutrophil; tumor necrosis factor-α; gastric mucosal integrity [ABSTRACT FROM AUTHOR]

Pulsed steroid therapy may induce rapid remission in patients with moderately severe ulcerative colitis in outpatient clinics. A total of 19 patients with moderately severe active ulcerative colitis who refused hospitalization were treated between October 1999 and September 2001 in the outpatient clinic. Patients were treated with either conventional oral steroid therapy or intravenous pulsed steroid therapy followed by conventional oral steroid therapy. Eight patients received conventional steroid therapy and 11 patients received pulsed steroid therapy followed by conventional steroid therapy. The efficacies of the two types of steroid therapy were equal, but patients with active colitis responded more quickly to pulsed steroid therapy than to conventional steroid therapy. No serious adverse effects were observed. Moderately severe colitis can be safely treated with either conventional or pulsed steroid therapy in the outpatient clinic, but pulsed steroid therapy may induce clinical remission more quickly than conventional steroid therapy. [ABSTRACT FROM AUTHOR]

Submucosal injection of endothelin (ET)-1 induces gastric ulcer. We investigated the roles of neutrophils and adhesion molecules (intercellular adhesion molecule (ICAM)-1 and CD18) in the development of ET-1-induced ulcers in rats. Ulcers were induced by submucosal injection of ET-1. Rats were injected with anti-neutrophil serum or F(ab')2 fragments of irrelevant mouse IgG2a (control), anti-ICAM-1 antibody, or anti-CD18 antibody. Ulcer tissues were subjected to measurement of myeloperoxidase (MPO) activity, ulcer size, and immunohistochemical study. Within 3 hr, arterial vasoconstriction and vascular congestion were observed at sites of ET-1 injection. By 6 hr, vascular congestion had disappeared, and ICAM-1 expression had markedly increased in venules in deep portions of the mucosa and submucosa, accompanied by an increase in the number of CD18-positive neutrophils. By 48 hr, ulcers that extended into the submucosa had developed. In controls, MPO activity gradually increased and was maximal by 6 hr. Neutrophil depletion, and immunoneutralizing of ICAM-1 and CD18 inhibited the increase in MPO activity, and decreased ulcer sizes measured at 48 hr. In conclusion, ET-1 causes ischemia-reperfusion injury, and neutrophil accumulation after reperfusion mediated by the ICAM-1-CD18 pathway may be important in the development of ET-1-induced gastric ulcer. [ABSTRACT FROM AUTHOR]

Studies the polyamine metabolism of rat gastric mucosa following oral administration of hypertonic sodium chloride solution. Inhibition of the increase in putrescine level; Factors involved in the formation of putrescine; Rates of cell growth in gastrointestinal mucosa.

Acute Helicobacter pylori infection produces predominantly neutrophilic infiltration of the gastric mucosa. However, the precise mechanisms and mediators of neutrophil migration are not known. Interleukin-8 (IL-8), a potent chemotactic factor for neutrophils, is present at high concentration in the gastric mucosa of subjects with chronic gastritis caused by H. pylori infection. The aims of this study were to determine whether IL-8 stimulates polymorphonuclear leukocyte (PMN) migration across a cultured monolayer of rabbit gastric epithelial cells and whether PMN migration affects epithelial cell barrier function. Confluent gastric epithelial monolayers grown on the inserts were overlaid with PMNs and various amounts of IL-8 were administered into the well under the insert. Gastric epithelial barrier function was assessed by sodium back diffusion. IL-8 stimulated PMN migration across the monolayer in a dose- and time-dependent manner. PMN transmigration significantly increased sodium back diffusion. In conclusion, IL-8 induces PMN migration across a monolayer of cultured gastric epithelial cells. This IL-8 action is associated with impairment of gastric epithelial barrier function. Since H. pylori infection causes a local mucosal increase of IL-8, our present findings may explain the mechanism of H. pylori-induced PMN infiltration of the gastric glands and mucosal injury. [ABSTRACT FROM AUTHOR]

Abstract: Helicobacter pylori (H. pylori)-induced immune responses in the gastric mucosa are skewed toward T helper (Th) 1 phenotype, which is characterized by predominant production of tumor necrosis factor (TNF)-α and interferon (IFN)-γ by helper T cells. Toll-like receptors (TLRs) play an essential role in mucosal defense against microbes through the recognition of bacterial molecules. Among the members of the TLR family, TLR9 recognizes bacterial unmethylated CpG DNA sites, and signal transduction of TLR9 induces production of a variety of cytokines, including type-I IFN (IFN-α/β). We investigated the expression and role of TLR9 in H. pylori-induced gastritis in mice. Expression of TLR9 mRNA in the gastric tissue increased after infection with H. pylori. TLR9 was mainly expressed in the macrophages, dendritic cells, and CD3+ cells in the gastric mucosa. Neutrophil infiltration and the expression levels of TNF-α and IFN-γ mRNA were higher in TLR9 knockout (KO) mice than in wild-type mice at 2 and 4months after H. pylori inoculation. These differences in inflammatory parameters between H. pylori-infected wild-type and TLR9 KO mice disappeared 6months after H. pylori inoculation. Expression of interleukin-4 mRNA, typical Th2 cytokine, in the gastric tissue did not differ between H. pylori-infected wild-type and TLR9 KO mice. Expression level of IFN-α/β mRNA in the TLR9 KO mice was lower than that in wild-type mice by 4months after inoculation. Administration of IFN-α reduced H. pylori infection-induced increase in neutrophil infiltration and the expression levels of TNF-α and IFN-γ mRNA in TLR9 KO mice. Our findings suggest that TLR9 signaling plays important roles in the suppression of H. pylori-induced gastritis in the early phase via downregulation of Th1-type cytokines modulated by IFN-α. [Copyright &y& Elsevier]