Quantitative analysis of amino Acid oxidation markers by tandem mass spectrometry.

Oxidative stress plays a central role in the pathogenesis of diverse chronic inflammatory disorders including diabetic complications, cardiovascular disease, aging, neurodegenerative disease, autoimmune disorders, and pulmonary fibrosis. Protein misfolding can lead to chronic endoplasmic reticulum (ER) stress which can exacerbate oxidative stress. This can trigger apoptotic cascades resulting in chronic inflammatory disorders. Despite intense interest in origins and magnitude of oxidative stress, ability to quantify oxidants has been limited because they are short lived. We have developed quantitative mass spectrometry (MS)-based analytical strategies to analyze stable end products of protein oxidation. These molecules provide quantitative and mechanistic assessment of degree of oxidative stress in cell cultures, tissues, and biofluids of animal models of disease and human samples. Our studies support the hypothesis that unique reactive intermediates generated in localized microenvironments of vulnerable tissues promote end-organ damage. The ability to quantify these changes and assess response to therapies will be pivotal in understanding disease mechanisms and monitoring efficacy of therapy.