Up-regulation of gastric mucosal inflammatory responses to Helicobacter pylori lipopolysaccharide by aspirin but not indomethacin

Effect of moxibustion stimulation on repair of gastric mucosal lesions in rats after peroneal neurotomy

AIM: To explore the mechanism underlying the protective effect of moxibustion on gastric mucosal lesions by investigating the relationship between endogenetic information started by moxibustion and the peroneal nerve pathways.

METHODS: Forty-eight SD rats were randomly and equally divided into four groups: a normal group (A), a model group (B), a gastric mucosal injury + moxibustion group (C), and a gastric mucosa injury + moxibustion + surgery group (D). Groups C and D were given 3 days of recovery after reroneal neurotomy. Group A was given saline and the other 3 groups were administered absolute ethanol and aspirin to induce gastric mucosa injury. After that, moxibustion was applied on Zusanli (ST36) in groups C and D, twice a day for 3 days. Finally, gastric ulcer index (UI) was assessed by gastric biopsy, gastric mucosa repair related cytokines such as epidermal growth factor (EGF) and prostaglandin E₂ (PGE₂) were detected, and mucosal apoptosis index (AI) was evaluated.

RESULTS: The improvement of UI was better in group C than in group D (P = 0.014). Compared with group C, serum and gastric levels of EGF and PGE₂ (EGF in serum P = 0.003, EGF in tissue P = 0.000; PGE₂ in serum P = 0.002, PGE₂ in tissue P = 0.000), and mucosal AI (P = 0.000) did not significantly rise in group D.

CONCLUSION: Moxibustion on Zusanli can transmit information by peroneal nerve pathways to regulate the release of gastric mucosal protective factors and the expression of apoptosis-related proteins, thus achieving the effect of repairing the gastric mucosa.

Induction of cyclooxygenase 2 by Escherichia coli but not Helicobacter pylori lipopolysaccharide in gastric epithelial cells in vitro

BACKGROUND

Cyclooxygenase 2 (COX-2) is an inducible enzyme that plays a key role in the synthesis of prostaglandins in response to inflammatory stimuli. It is expressed in the gastric mucosa as part of the response to infection with Helicobacter pylori. The specific interaction between H. pylori and the gastric epithelium that results in COX-2 expression has not been identified.

METHODS

In order to investigate the hypothesis that lipopolysaccharide (LPS) from H. pylori plays a role in the induction of cyclooxygenase 2 in the stomach, gastric cell lines MKN-7 and MKN-45 were incubated with LPS from either H. pylori NCTC 11637 or Escherichia coli 055:B5. Incubation of cells with live H. pylori NCTC 11637 was also carried out as a positive control. Cells were then analysed for COX-2 protein and mRNA and prostaglandin E2 synthesis.

RESULTS

Cyclooxygenase 2 protein and mRNA expression was induced by E. coli LPS and live H. pylori, but not by H. pylori LPS. Prostaglandin E2 synthesis increased in a dose-dependent manner in both cell lines with E. coli but not H. pylori LPS.

CONCLUSIONS

H. pylori LPS is of low biological activity when compared with E. coli LPS in its ability to induce the expression of cyclooxygenase 2 and synthesis of prostaglandin E2. This may provide one mechanism by which H. pylori minimizes the inflammatory response in the gastric mucosa, allowing chronic infection.

Helicobacter pylori lipopolysaccharide in the IL-2 milieu activates lymphocytes from dyspeptic children

In this study, we assessed the proliferative response of peripheral blood mononuclear leukocytes (PBML) from 33 children/young adolescents with chronic dyspepsia, to H. pylori LPS in the presence and absence of IL-2 as a T cell growth factor. A rapid urease test (RUT) and a presence of Helicobacter-like organisms (HLO) in the biopsy specimens allowed us to distinguish RUT/HLO-positive (17/33) and -negative (16/33) patients. H. pylori LPS alone induced a proliferation of PBML from 4 out of 33 dyspeptic patients. IL-2 increased the prevalence of the response to LPS to 59% and 74% of RUT/HLO-positive and -negative patients, respectively. PBML from RUT/HLO-positive patients responded significantly less intensively to H. pylori LPS in the presence of IL-2, to IL-2 alone and to H. pylori LPS+IL-2. However, there was no difference in PHA-driven proliferation of PBML from the patients of those two groups. A negative correlation between the responsiveness to H. pylori LPS of PBML and occurrence of type B inflammation in gastric mucosa was demonstrated. The results suggest a contribution of H. pylori LPS to an outcome of H. pylori infection. It is speculated that H. pylori LPS by an activation of immunocompetent cells may reduce gastric inflammation, decrease bacterial load and prolong H. pylori infection.