Showing papers by "Hirohisa Machida published in 2009"

Bile acids induce cdx2 expression through the farnesoid x receptor in gastric epithelial cells.

Abstract: Clinical and experimental studies showed that the reflux of bile into the stomach contributes to the induction of intestinal metaplasia of the stomach and gastric carcinogenesis. Caudal-type homeobox 2 (Cdx2) plays a key role in the exhibition of intestinal phenotypes by regulating the expression of intestine-specific genes such as goblet-specific gene mucin 2 (MUC2). We investigated the involvement of the farnesoid X receptor (FXR), a nuclear receptor for bile acids, in the chenodeoxycholic acid (CDCA)-induced expression of Cdx2 and MUC2 in normal rat gastric epithelial cells (RGM-1 cells). RGM-1 cells were treated with CDCA or GW4064, an FXR agonist, in the presence or absence of guggulsterone, an FXR antagonist. CDCA induced dose-dependent expression of Cdx2 and MUC2 at both the mRNA and protein levels. The maximum stimulation of Cdx2 and MUC2 mRNA induced by CDCA was observed at 3 h and by 6 h, respectively. GW4064 also induced expression of these molecules. The effects of CDCA and GW4064 on expression of Cdx2 and MUC2 were abolished by guggulsterone. These findings suggest that bile acids may induce gastric intestinal metaplasia and carcinogenesis through the FXR.

Lansoprazole, a Proton Pump Inhibitor, Suppresses Production of Tumor Necrosis Factor-α and Interleukin-1β Induced by Lipopolysaccharide and Helicobacter Pylori Bacterial Components in Human Monocytic Cells via Inhibition of Activation of Nuclear Factor-κB and Extracellular Signal-Regulated Kinase

Abstract: Pathogenic bacterial components play critical roles in initiation of gastrointestinal inflammation via activation of intracellular signaling pathways which induce proinflammatory cytokines such as tumor necrosis factor (TNF)-α and interleukin (IL)-1β. Lansoprazole (LANSO), a proton pump inhibitor, has been widely used for the treatment of peptic ulcers and reflux esophagitis due to its potent acid-suppressive effect. It has also been reported to have anti-inflammatory effects. In this study we investigated the effects of LANSO on the production of TNF-α and IL-1β induced by lipopolysaccharide (LPS) and Helicobacter pylori water-soluble extract (HpWE) in the human monocytic cell line (THP-1). LANSO (100 µM) significantly reduced mRNA expression and production of TNF-α and IL-1β by THP-1 cells stimulated by LPS and HpWE. LANSO inhibited phosphorylation and degradation of inhibitory factor κB-α (IκB-α) and phosphorylation of extracellular signal-regulated kinase (ERK) induced by LPS and HpWE in THP-1 cells. These findings suggest that LANSO exerts anti-inflammatory effects by suppressing induction of TNF-α and IL-1β via inhibition of nuclear factor (NF)-κB and ERK activation.

Prevalence of mid-gastrointestinal bleeding in patients with acute overt gastrointestinal bleeding: multi-center experience with 1,044 consecutive patients.

Abstract: Video capsule endoscopy (VCE) and double-balloon enteroscopy (DBE) enable the detection of small intestinal lesions. To examine causes of acute overt gastrointestinal (GI) bleeding and the prevalence of mid-GI bleeding, defined as small intestinal bleeding from the ampulla of Vater to the terminal ileum, in a multi-center experience in Japan in the VCE/DBE era. Data were collected retrospectively from consecutive patients with acute overt GI bleeding in ten participating hospitals. All patients were examined by esophagogastroduodenoscopy and/or colonoscopy. When the source of bleeding was not identified after these procedures, patients suspected to have mid-GI bleeding were referred to our hospital and VCE/DBE was performed to determine the source of bleeding. Of the 1044 patients with acute overt GI bleeding, 524 (50.2%) patients were diagnosed with upper GI bleeding, 442 (42.3%) with lower GI bleeding, and 13 (1.2%) with mid-GI bleeding. Gastric ulcer was the most common cause of bleeding (20.4%). Among cases of mid-GI bleeding, ulcers were found in 4 (30.8%) patients, erosions in 3 (23.1%), angiodysplasia in 3 (23.1%), submucosal tumor in 2 (15.4%), and hemangioma in one (7.7%). Seven lesions were located in the jejunum, 5 in the ileum, and one in both the jejunum and ileum. Analysis of age-related cause showed that the prevalence of mid-GI bleeding among younger patients under 40 years of age was higher (5%) than in other age groups (1–2%). mid-GI bleeding is rare among Japanese patients with acute overt GI bleeding.