Background/Aims: Cytokines and adhesion molecules regulate many inflammatory processes in several gastrointestinal diseases. The dynamics of cytokines and adhesion molecules in reflux esophagitis are unknown in detail. We examined the expression and dynamics of interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), monocyte chemotactic protein-1 (MCP-1), macrophage inflammatory protein-1α (MIP-1α), MIP-2, GRO/cytokine-induced neutrophil chemoattractant-2α (CINC-2α), intercellular adhesion molecule-1 (ICAM-1), leukocyte function-associated antigen 1 (LFA-1; CD11a/CD18), and Mac-1 (CD11b/CD18) in rat chronic reflux esophagitis. Methods: Chronic acid reflux esophagitis was induced in Wistar rats by ligating the transitional region between the forestomach and the glandular portion and wrapping the duodenum near the pylorus with a small piece of an 18-Fr Nélaton catheter. Rats were killed 3 or 21 days after operation. The levels of mRNA expression of cytokines and ICAM-1 were determined by real-time quantitative RT-PCR. Localization of adhesion molecules and cytokines was investigated by immunohistochemical staining, and numbers of LFA-1- or Mac-1-positive cells were quantified. Results: IL-1β, TNF-α, MCP-1, MIP-1α, MIP-2, CINC-2α, and ICAM-1 mRNA expression was significantly increased in esophageal lesions compared with normal esophagus. There were few these cytokines- or adhesion molecule-positive cells in normal esophagus. In regions of esophagitis, numerous inflammatory leukocytes in lamina propria and the submucosal layer exhibited positive reactions for these cytokines and endothelial cells were intensely stained for ICAM-1. Numbers of LFA-1- and Mac-1-positive cells were significantly increased in rat chronic esophagitis. Treatment with rabeprazole almost completely inhibited development of chronic acid reflux esophagitis and significantly decreased expression of cytokines and ICAM-1 mRNA in esophageal tissue compared with control. Conclusion: Cytokines and adhesion molecules play important roles in the pathogenesis of chronic reflux esophagitis in this rat model.

TNF-alpha has numerous biological activities, including the induction of chemokine expression, and is involved in many gastric injuries. C-C chemokines [monocyte chemotactic protein (MCP)-1 and macrophage inflammatory protein (MIP)-1alpha] and C-X-C chemokines [MIP-2 and cytokine-induced neutrophil chemoattractant (CINC)-2alpha] mediate chemotaxis of monocytes and neutrophils, respectively. We examined the roles of TNF-alpha and dynamics of chemokine expression in gastric ulceration including ulcer recurrence and indomethacin-induced injury. Rats with healed chronic gastric ulcers received intraperitoneal TNF-alpha to induce ulcer recurrence. Some rats were given neutralizing antibodies against neutrophils or MCP-1 together with TNF-alpha. In a separate experiment, rats were orally administered 20 mg/kg indomethacin with or without pretreatment with pentoxifylline (an inhibitor of TNF-alpha synthesis) or anti-MCP-1 antibody. TNF-alpha (1 microg/kg) induced gastric ulcer recurrence after 48 h, which was completely prevented by anti-neutrophil antibody. TNF-alpha increased the number of macrophages and MCP-1 mRNA expression in scarred mucosa from 4 h, whereas it increased MPO activities (marker of neutrophil infiltration) and mRNA expression of MIP-2 and CINC-2alpha from 24 h. Anti-MCP-1 antibody inhibited leukocyte infiltration with reduction of the levels of C-X-C chemokines and prevented ulcer recurrence. Indomethacin treatment increased TNF-alpha/chemokine mRNA expression from 30 min and induced macroscopic erosions after 4 h. Pentoxifylline inhibited the indomethacin-induced gastric injury with reduction of neutrophil infiltration and expression of chemokine (MCP-1, MIP-2, and CINC-2alpha). Anti-MCP-1 antibody also inhibited the injury and these inflammatory responses but did not affect TNF-alpha mRNA expression. In conclusion, increased MCP-1 triggered by TNF-alpha may play a key role in gastric ulceration by regulating leukocyte recruitment and chemokine expression.

Neutrophil infiltration mediated by TNF-alpha 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 PGE2 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 PGE2 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 PGE2 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-alpha mRNA expression in the stomach, which was further increased by indomethacin. Effects of COX inhibitors on neutrophil infiltration, apoptosis, and TNF-alpha expression in H. pylori-infected mice were abolished by exogenous 16,16-dimethyl PGE2. In conclusion, PGE2 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-alpha expression.

Previously purified and isolated compounds of novel alkyl methyl quinolone alkaloids (AM quinolones) from Gosyuyu (Wu-Chu-Yu), a Chinese herbal medicine, have a strong and highly selective antibacterial activity against Helicobacter pylori in vitro. To clarify the antibacterial mechanism(s) of AM quinolones, we examined the effects of AM quinolones on respiration of H. pylori in vitro. One week after treatment with AM quinolones alone (2, 10 or 20 mg/kg/day, orally) or combinations of AM quinolones and omeprazole (30 mg/kg/day) for H. pylori (1 x 10(8) cfu)-infected Mongolian gerbils, we checked viable H. pylori and myeloperoxidase (MPO) activity in the gastric tissues. AM quinolones decreased the number of H. pylori and inhibited H. pylori respiration in a dose-dependent manner. AM quinolones decreased the number of viable H. pylori (AM quinolones alone: 46.0 +/- 22.6 x 10(4), 17.3 +/- 4.9 x 10(4) and 8.1 +/- 6.6 x 10(4) cfu/stomach, respectively; and combinations of AM quinolones and omeprazole: 8.0 +/- 5.6 x 10(4), 4.2 +/- 2.5 x 10(4) and 5.5 +/- 2.7 x 10(4) cfu/stomach) compared with the vehicle-treated group (control: 359.9 +/- 180.3 x 10(4) cfu/stomach). AM quinolones significantly decreased MPO activity of H. pylori-inoculated gastric tissues. These findings suggest that AM quinolones have a potent antibacterial effect against H. pylori through respiratory inhibition, and reduced bacterial growth in vivo. AM quinolones might be novel therapeutic agents for H. pylori eradication.

Epidermal growth factor (EGF) is predominantly secreted by salivary glands and activates Na(+)/H(+) exchanger-1 (NHE-1), which regulates intracellular pH (pH(i)). We investigated the roles of EGF and NHE-1 in esophageal epithelial defense against acid using human esophageal epithelial cell lines and a rat chronic esophagitis model. Esophageal epithelial cells were incubated with acidified medium in the absence or presence of EGF. Cell viability and changes in pH(i) were measured. Chronic acid reflux esophagitis was induced in rats with and without sialoadenectomy. Esophageal lesion index, epithelial proliferation, and expression of EGF receptors and NHE-1 were examined. EGF protected esophageal epithelial cells against acid in a dose-dependent manner, and the cytoprotective effect of EGF was completely blocked by treatment with NHE-1 inhibitors. Tyrosine kinase, calmodulin, and PKC inhibitors significantly inhibited cytoprotection by EGF, whereas MEK, phosphatidylinositol 3-kinase, and PKA inhibitors had no effect. EGF significantly increased pH(i) recovery after NH(4)Cl pulse acidification, and this increase in pH(i) recovery was significantly blocked by inhibitors of calmodulin and PKC. Sialoadenectomy led to an increase in the severity of chronic esophagitis but affected neither epithelial proliferation nor expression of EGF receptors. Expression of NHE-1 mRNA was increased in esophagitis and upregulated in rats with sialoadenectomy. The increasing severity of esophagitis in rats with sialoadenectomy was prevented by exogenous administration of EGF. In conclusion, EGF protects esophageal epithelial cells against acid through NHE activation via Ca(2+)/calmodulin and the PKC pathway. Deficiency in endogenous EGF is associated with increased severity of esophagitis. EGF and NHE-1 play crucial roles in esophageal epithelial defense against acid.