thromboxane-b2 and Helicobacter-Infections

We aimed at investigating the relationship between Helicobacter pylori infection and in vivo lipid peroxidation and platelet activation, as reflected by urinary 8-iso-prostaglandin (PG)F(2alpha) and 11-dehydro-thromboxane (TX)B2, respectively, in otherwise healthy dyspeptic subjects.. We measured urinary 8-iso-PGF2alpha and 11-dehydro-TXB2 excretion in 40 dyspeptic subjects with a positive 13C-urea breath test and 38 dyspeptic individuals with a negative test. Moreover, we investigated the effects of H pylori eradication on prostanoid metabolite excretion in 23 H pylori-positive subjects. We also measured prostanoid metabolite excretion before and after selective cyclooxygenase-2 inhibition with rofecoxib in 4 H pylori-positive subjects. Urinary 8-iso-PGF2alpha and 11-dehydro-TXB2 excretion was significantly higher in the H pylori-positive individuals than in controls. A significant direct correlation was found between the degree of positivity to the 13C-urea breath test and urinary 8-iso-PGF2alpha excretion. The latter was linearly correlated with urinary 11-dehydro-TXB2. Successful eradication of H pylori infection led to a significant reduction in both 8-iso-PGF(2alpha) and 11-dehydro-TXB2. Furthermore, their levels were unaffected after treatment with rofecoxib.. Our study provides evidence of enhanced in vivo lipid peroxidation and platelet activation in association with H pylori infection and suggests a novel mechanism by which an infectious agent could contribute to atherothrombosis.

Topics: Adult; Aged; Cross-Sectional Studies; Cyclooxygenase 2; Cyclooxygenase 2 Inhibitors; Cyclooxygenase Inhibitors; Dinoprost; Fasting; Helicobacter Infections; Helicobacter pylori; Humans; Lipid Peroxidation; Male; Membrane Proteins; Middle Aged; Platelet Activation; Prostaglandin-Endoperoxide Synthases; Thromboxane B2

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.

Topics: Animals; Anti-Inflammatory Agents; Apoptosis; Blotting, Western; Cyclooxygenase 1; Cyclooxygenase 2; Cyclooxygenase 2 Inhibitors; Cyclooxygenase Inhibitors; Dinoprostone; Epithelial Cells; Female; Gastric Mucosa; Gastritis; Helicobacter Infections; Helicobacter pylori; Indomethacin; Isoenzymes; Membrane Proteins; Mice; Mice, Inbred C57BL; Prostaglandin-Endoperoxide Synthases; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Thromboxane B2; Tumor Necrosis Factor-alpha

Topics: 6-Ketoprostaglandin F1 alpha; Adult; Chronic Disease; Female; Gastric Juice; Gastric Mucosa; Gastritis; Helicobacter Infections; Helicobacter pylori; Humans; Male; Peptic Ulcer; Prostaglandins; Thromboxane B2

Colonisation with Helicobacter pylori may influence susceptibility to gastroduodenal injury and ulceration in patients taking non-steroidal anti-inflammatory drugs (NSAIDs). The aim of this study was to determine if Helicobacter pylori colonisation altered eicosanoid synthesis by gastric mucosa in these patients. Sixty five patients with long-standing NSAID intake and 23 control subjects underwent endoscopy. In vitro gastric antral biopsies were stimulated by vortex mixing and eicosanoid measurements determined by radioimmunoassay. Helicobacter pylori colonisation was determined by a CLO test (a gel based rapid urease test) and histological assessment. Median prostaglandin E2 synthesis by gastric mucosa was 61.0 (interquartile range: 19.2-73.1) pg/mg in control subjects colonised with Helicobacter pylori compared with 46.5 (23.3-65.5) pg/mg in Helicobacter pylori negative subjects. This was not significantly different. Treatment with NSAIDs was associated with a significant difference (p < 0.001) in prostaglandin E2 (PGE2) synthesis between those colonised with Helicobacter pylori (37.5(22.0-77.3) pg/mg) compared with patients not infected (12.6(7.0-19.3) pg/mg). Values in patients taking NSAIDs who were colonised were not different from control subjects. Synthesis of PGE2 was strongly associated with type B (chronic active), but not type C (chemical) gastritis. Dyspeptic symptoms were more common in subject colonised with Helicobacter pylori (p < 0.002) and were associated with higher PGE2 synthesis. In patients taking NSAIDs Helicobacter pylori colonisation removes rather then enhances depression of PGE2 synthesis associated with NSAIDs and may promote dyspepsia associated with ulcers and prevent superficial mucosal injury.

Topics: Anti-Inflammatory Agents, Non-Steroidal; Arthritis; Dinoprostone; Female; Gastric Mucosa; Gastritis; Helicobacter Infections; Helicobacter pylori; Humans; Male; Middle Aged; Smoking; Stomach Ulcer; Thromboxane B2