Oxidative stress biomarkers

Oxidative stress is the result of the imbalance between reactive oxygen species (ROS) formation and enzymatic and nonenzymatic antioxidants. During the past decade, research has revealed a widespread involvement of oxidative stress in a number of disease processes. Therefore, oxidative stress biomarkers are relevant in the evaluation of the disease status and the health-enhancing effects of antioxidants. Although identifying markers of oxidative stress has been the focus of many studies, and several markers from various biomolecule sources have been proposed, for some of them (ROS in leukocytes and platelets by flow cytometry, markers based on ROS-induced modifications of lipids, DNA, and proteins, enzymatic players of redox status and total antioxidant capacity of human body fluids) there is a lack of consensus concerning validation, standardization, and reproducibility. We developed a new method for evaluating the leukocytes redox status by flow citometry. Using the ratio between lipid peroxidative damage induced by exogenous peroxyl radicals and oxidative burst in the presence and absence of a standard antioxidant we defined the Peroxidation of Leukocytes Index Ratio (PLIR). The latter, supplies additional information with respect to commonly used methods to assess antioxidant status and reflects the complex relationship between scavenger and reducing antioxidant activities with leukocytes responses and lipid peroxidation. In particular, PLIR is able to appreciate the potentially dangerous effect of uric acid, one of the main endogenous danger signals for the immune system, on innate immune response. For this reason, this new method is useful to evaluate the redox status of leukocytes in both pathological conditions and situation of increased risk of disease, as well as the impact of lifestyle and dietary habit, as health modification factors.