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Notizen: Aim:  Trefoil factor family (TFF) peptides are known to facilitate wound healing in gastric mucosa. However, the regulatory mechanisms of gastric TFF expression are not fully understood yet. In this study, we examined the effect of TNF-α on TFF1 and TFF2 expression in gastric epithelial cells.Methods:  MKN45 cells were used. TFF mRNA expression was analyzed by real-time quantitative RT-PCR. Promoter sequences of TFF1 gene (−956 to +36) and TFF2 gene (−912 to +24) were inserted into pGL3 vector and reporter gene assays were performed. NF-κB activity was monitored by using a NF-κB responsive element-driven reporter vector.Results:  (1) TNF-α(0.1–30 ng/ml) down-regulated TFF1 and TFF2 mRNA expression in a dose-dependent manner. (2) Reporter gene assays also confirmed the down-regulation of TFF1 and TFF2 gene transcription by TNF-α. (3) TNF-α activated NF-κB. (4) Overexpression of dominant negative IκBα prevented both TNF-α-induced NF-κB activation and TNF-α-induced down-regulation of TFF expression.Conclusions:  TNF-α down-regulates gastric TFF expression through NF-κB pathway, suggesting that TFF expression is sensitive to inflammatory stimuli.

Notizen: Non-alcoholic steatohepatitis is a distinct entity, characterized by fatty change, lobular inflammation and fibrosis of the liver. Some cases of non-alcoholic steatohepatitis progress to cirrhosis, but it is not easy to distinguish this disease from non-alcoholic fatty liver by non-invasive examinations. No proven therapy for non-alcoholic steatohepatitis exists. Transforming growth factor-β1 is implicated in the development of liver fibrosis, and is inhibited by α-tocopherol (vitamin E) in the liver. Therefore, in this study, the significance of the measurement of the level of plasma transforming growth factor-β1 and the effect of α-tocopherol on the clinical course of non-alcoholic steatohepatitis were investigated.〈section xml:id="abs1-2"〉〈title type="main"〉Methods:Twelve patients with non-alcoholic steatohepatitis and 10 patients with non-alcoholic fatty liver, with a diagnosis confirmed by liver biopsy, were studied. None of the patients had a history of alcohol abuse, habitual medicine or malignant or inflammatory diseases. All patients were negative for hepatitis B, C and G virus. Patients were given dietary instruction for 6 months, and then α-tocopherol (300 mg/day) was given for 1 year. Blood chemistries, measurement of plasma transforming growth factor-β1 level and liver biopsies were undertaken before and after the 1-year α-tocopherol treatment.〈section xml:id="abs1-3"〉〈title type="main"〉Results:The serum alanine transaminase level decreased in non-alcoholic fatty liver patients, but not in non-alcoholic steatohepatitis patients, after 6 months of dietary therapy. Although the serum alanine transaminase level in non-alcoholic steatohepatitis patients was reduced during the 1-year α-tocopherol treatment, α-tocopherol had no effect on the serum alanine transaminase level in non-alcoholic fatty liver patients. The histological findings, such as steatosis, inflammation and fibrosis, of the non-alcoholic steatohepatitis patients were improved after α-tocopherol treatment. The plasma transforming growth factor-β1 level in non-alcoholic steatohepatitis patients was significantly elevated compared with that in non-alcoholic fatty liver patients and healthy controls, and decreased, accompanied by an improvement in serum alanine transaminase level, with α-tocopherol treatment.〈section xml:id="abs1-4"〉〈title type="main"〉Conclusions:lOur data suggest that the measurement of the level of plasma transforming growth factor-β1 represents a possible method of distinguishing between non-alcoholic steatohepatitis and non-alcoholic fatty liver. Long-term α-tocopherol treatment may be safe and effective for non-alcoholic steatohepatitis. A randomized, controlled, double-blind trial is needed to confirm the full potential of α-tocopherol in the management of non-alcoholic steatohepatitis.

Notizen: Background : Trefoil factor family peptides are expressed in gastrointestinal epithelial cells and play a critical role in maintaining mucosal integrity. Although non-steroidal anti-inflammatory drugs (NSAIDs) are important causative agents of gastric mucosal lesions, few data are available about the effect of NSAIDs on trefoil family peptides in gastric mucosa.Aim : To examine whether indometacin, a widely used NSAID, affects trefoil factor family expression in gastric epithelial cells.Methods : MKN45, a cell line derived from human gastric cancer, was used. TFF1, TFF2, and TFF3 mRNA expression was assessed by real-time quantitative reverse transcription-polymerase chain reaction (RT-PCR). TFF2 gene transcription was also examined by luciferase reporter gene assay.Results : Relative expression level of TFF1, TFF2, TFF3 mRNA was 616: 12: 1 in unstimulated MKN45 cells. Although indometacin (1–250 µmol/L) had no significant effect on the expression of TFF1 and TFF3 mRNA, it up-regulated TFF2 mRNA expression in a dose- and time-dependent manner. Luciferase reporter gene assay confirmed the up-regulation of TFF2 gene transcription by indometacin. Indometacin-induced up-regulation of TFF2 expression was not antagonized by externally applied prostaglandin E2.Conclusion : These results suggest that indometacin up-regulates gastric epithelial cell TFF2 expression through a COX-independent mechanism. Since TFF peptides play an important role in gastric mucosal protection, indometacin-induced TFF2 may reduce the degree of gastric mucosal damage induced by indometacin.

Notizen: Peroxisome proliferator-activated receptors (PPAR) are a family of three nuclear receptors (PPARα, PPARδ, and PPARγ). Although recent evidence suggests a role for PPARγ in the regulation of colonic epithelial cell growth, the role for PPARγ in the stomach has not been established.〈section xml:id="abs1-2"〉〈title type="main"〉Aim:To examine the expression of PPARγ and the effects of PPARγ ligands on the viability of gastric epithelial cells.〈section xml:id="abs1-3"〉〈title type="main"〉Methods:MKN45 cells and primary cultured rat gastric epithelial cells were used. Troglitazone (TGZ) and 15-deoxy-Δ12, 14-prostaglandin J2 (15d-PGJ2) were used as PPARγ ligands. Expression of PPARγ was examined by RT–PCR and Western blot analysis. Cell viability was measured by WST-1 assay and TUNEL assay was performed to detect apoptosis.〈section xml:id="abs1-4"〉〈title type="main"〉Results:MKN45 cells expressed all subtypes of PPAR. PPARγ ligands decreased cell viability and induced cell death in a dose-dependent manner, whereas ligands for PPARα and PPARδ had no significant effect. TUNEL assay showed that this cell death is apoptosis. Primary cultured rat gastric epithelial cells also expressed PPARγ and activation of PPARγ decreased cell viability.〈section xml:id="abs1-5"〉〈title type="main"〉Conclusion:These results suggest that PPARγ plays an important role in the regulation of cell growth and cell death in gastric epithelial cells.

Notizen: Background: Helicobacter pylori-associated inflammation leads to exposure of the gastric epithelium to reactive oxygen species (ROS) generated in the gastric mucosa. In some pathological conditions, such as those induced by nonsteroidal anti-inflammatory drugs, the gastric mucosa may become more susceptible to ROS. Aim: To examine the effects of aspirin on antioxidant defenses as well as on oxidant injury in cultured rat gastric mucosal cells. Methods: Primary monolayer cultures of rat gastric fundic mucosa were exposed to an ROS-generating system, hypoxanthine/xanthine oxidase (XOD). Cytotoxicity was quantified by measuring 51Cr release from prelabelled cells. The effects of aspirin on antioxidants and on cellular injury brought about by the ROS-generating system were determined. Results: XOD, in the presence of hypoxanthine, caused a dose-dependent increase in specific 51Cr release, which corresponded to the ability of XOD to produce ROS (as assessed by the production of uric acid from hypoxanthine). Incubation of cells with aspirin (1–100 μm) produced a dose-dependent increase in XOD-induced 51Cr release. Aspirin did not affect cellular glutathione content or activity of glutathione peroxidase, glutathione reductase or endogenous catalase. By contrast, aspirin caused a dose-dependent reduction in mucus synthesis, as assessed by incorporation of [3H]-glucosamine hydrochloride into the cells. Conclusions: Aspirin at therapeutically relevant concentrations rendered cultured gastric cells more susceptible to subsequent exposure to ROS. Aspirin affected neither the glutathione redox cycle nor catalase activity. Thus, the enhancement of ROS-induced injury by aspirin may be accomplished through diminished gastric mucus synthesis, since mucus is a potent scavenger of ROS. These findings provide insight into how gastric inflammation and injury (such as that induced by H. pylori infection) in human gastric mucosa is modulated by the administration of nonsteroidal anti-inflammatory drugs.

Notizen: Background: There is compelling evidence for the pivotal role of Helicobacter pylori in the pathogenesis of gastrointestinal ulcer disease. However, despite the bacterium's toxicity, the majority of H. pylori infections are not accompanied by gastric ulcers. This implies the existence of a host mechanism offsetting H. pylori toxicity. Aims: To evaluate gastric fibroblasts' expression of hepatocyte growth factor (HGF), which is known to facilitate gastric ulcer healing, in the presence of H. pylori; to compare the effect on H. pylori-induced HGF expression of a COX-2 selective inhibitor with that of nonselective nonsteroidal anti-inflammatory drugs (NSAIDs). Methods: Human gastric fibroblasts were cultured from human gastric mucosa obtained at surgery. Prostaglandin E2 (PGE2) and HGF were measured by EIA. The expression of COX-2 mRNA was assessed by the TaqMan quantitative RT-PCR system. Results: H. pylori increased PGE2 release in gastric fibroblasts. H. pylori induced expression of COX-2 mRNA, which indicates that PG induction by H. pylori is through COX-2. Sulindac sulphide, etodolac and NS 398 all inhibited H. pylori-induced PGE2 release to the same extent. These agents also inhibited H. pylori-induced HGF release. Conclusion: Gastric fibroblasts produce PG and HGF in response to the presence of H. pylori, which may be considered part of the human body's defensive reaction to H. pylori toxicity. This defensive mechanism is inhibited not only by COX-2 nonselective NSAIDs but also by a COX-2 selective inhibitor. These findings indicate the importance of COX-2 in chronic H. pylori infection.

Notizen: Background : The majority of gastro-oesophageal reflux disease (GERD) seems to be non-erosive reflux disease. Nonerosive reflux disease includes minimal change oesophagitis (whitish or reddish, oedematous change and erosion that is not regarded as mucosal break) and no endoscopic abnormalities.Aim : To investigate the accurate proportion of those with minimal change oesophagitis and to clarify its characteristics. In addition, we evaluated the effect of famotidine (40 mg/ day) in those with minimal change.Methods : Prospective endoscopic assessment was performed for consecutive 606 out-patients. Of the 582 patients suitable for analysis, 347 were non-treated. The latter were divided into those with erosive GERD or minimal change, and their endoscopic findings and characteristics were compared.Results : Among 347 non-treated patients, 88 (25%) had erosive GERD and 249 (72%) had minimal change. Compared with patients who have erosive GERD and those with minimal change, the latter were less likely to have hiatal hernia or bile reflux, but more likely to have gastric atrophy. Symptomatic patients (n = 55) with minimal change oesophagitis were more likely to have hiatal hernia than those who were asymptomatic (n= 194). Most patients preferred taking famotidine on-demand, during a 4-week follow-up period.Conclusions : Most non-erosive reflux disease can be classified as minimal change oesophagitis, and that have different characteristics from erosive GERD. On-demand famotidine may be a suitable alternative treatment for patients with minimal change disease.