Oxidative and nitrosative stress enzymes in relation to nitrotyrosine in Helicobacter pylori-infected humans.

Abstract

To compare a possible relation between Helicobacter pylori (H. pylori) and the oxygen- and nitrogen radical system in humans. Mechanisms for H. pylori to interfere with the oxygen and nitrogen radical system is of great importance for understanding of the H. pylori persistence and pathogenesis. Biopsies were obtained from the gastric wall of 21 individuals. Ongoing infection with H. pylori was detected using direct analyze from the biopsies using campylobacter-like organism test (CLO-test) and/or by using (14)C-urea breath test. The individuals were divided in a negative H. pylori and a positive H. pylori group. Expression in the gastric mucosa of inducible nitric oxide syntase (iNOS), nicotinamide adenine dinucleotide phosphate-oxidase (NADPH-oxidase) myeloperoxidase (MPO), and nitrotyrosine were assessed by Western blotting. The individuals who undervent gastroscopy were divided in a H. pylori neg. [n = 13, m/f = 7/6, age (mean) = 39] and a H. pylori pos. group [n= 8, m/f = 5/3, age (mean) = 53]. Using western blot analysis iNOS was detected as a 130 kDa band. The iNOS expression was upregulated in the antrum of H. pylori infected individuals in comparison to the controls, mean ± SD being 12.6 ± 2.4 vs 8.3 ± 3.1, P < 0.01. There was a markedly upregulated expression of MPO in the antrum of H. pylori infected individuals in comparison to the control group without infection. In several of non-infected controls it was not possible to detect any MPO expression at all, whereas the expression was high in all the infected subjects, mean ± SD being 5.1 ± 3.4 vs 2.1 ± 1.9, P < 0.05. The NADPH-oxidase expression was analysed by detecting the NADPH-oxidase subunit p47-phox expression. P47-phox was detected as a 47 kDa band using Western blot, and showed a significantly higher expression of p47-phox in the antrum of the H. pylori infected individuals compared to the controls, mean ± SD being 3.1 ± 2.2 vs 0.3 ± 0.2, P < 0.01. Regarding nitrotyrosine formation, Western blot did not show any significant increase or decrease compared to controls, 7.0 ± 0.9 vs 6.9 ± 1.1, not significant. iNOS, MPO and NADPH-oxidase was up-regulated among H. pylori infected. Regarding nitrotyrosine no difference was found. This support an H. pylori related inhibition of radical formation.