Dietary nitrite induces nitrosation of the gastric mucosa: the protective action of the mucus and the modulatory effect of red wine.

The stomach chemical environment promotes the production of new molecules that can induce post-translational modifications of endogenous proteins with physiological impact. The nitrate-nitrite-nitric oxide pathway is relevant in this process via production of nitric oxide ( • NO) and nitric oxide-derived nitrogen oxides (NOx) at high concentrations. Using a highly sensitive and selective chemiluminescence approach, we found that exposure the stomach of rats to nitrite yielded S - and N -nitroso derivatives in gastric mucus cysteine-rich glycoproteins (mucins). To lesser extent, the underlying epithelial cell layers also suffered nitrite-driven S - and N -nitroso modifications which increased upon mucus removal, indicating that, under normal nitrite load, • NO and NOx can reach inner layers of the stomach wall and locally modify proteins. S -nitrosation was by large the predominant modification. In vitro and ex vivo experiments indicated that the gastric nitrosation pattern is triggered by dietary nitrite in a concentration dependent manner, encompassing the intermediary formation of • NO and is susceptible to modulation by dietary reductants, notably red wine polyphenols. Collectively, these results suggest a protective action of the mucus and potential • NO-dependent biochemical effects at deeper cells layers of the mucosa. [ABSTRACT FROM AUTHOR]