Evaluation of oxidative stress biomarkers

Ruskovska, Tatjana and Jansen, Eugene (2012) Evaluation of oxidative stress biomarkers. In: Научно-стручен собир на Факултетот за медицински науки, Штип.

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Abstract

Oxidative stress is defined as a state resulting from an increased production of reactive oxygen species (ROS) and insufficient antioxidant defenses. ROS are metabolites of molecular oxygen (O2) generated as by-products of normal aerobic metabolism, and consist of: superoxide radical (.O2-), nitric oxide radical (.NO), hydroxyl radical (.OH-) and non-radicals such as hydrogen peroxide (H2O2) and peroxynitrite (ONOO-). Although usually regarded as toxic, ROS also serve as mediators of signal transduction and are essential for normal physiology. Moreover, they also have a protective function in the body, as in the case with the stimulation of ROS production by macrophages as an innate immune response to bacterial infection. However, chronic exposure to excessive ROS levels can lead to oxidative modification of proteins, lipids, carbohydrates, and DNA, resulting in tissue damage. The basic concept of the oxidative stress theory is easy to understand and therefore is very popular. Namely, almost everyone knows that chronic excess of free radicals leads to tissue damage and illness. This concept has further led to a widespread use of different kinds of antioxidant vitamins and supplements, which are taken by both general population and patients with different oxidative stress related pathologies, most often as uncontrolled self-prescription. At the same time the role of ROS in signal transduction is typically overlooked, which could be at least one of the reasons for the occurrence of adverse effects in supplementation with antioxidant vitamins. Thus, recent analysis of available clinical data about the effect of antioxidant supplements: β-carotene, vitamin A, vitamin C, vitamin E, and selenium for prevention of mortality in adults shows no evidence to support their use in both primary and secondary prevention. Moreover, it seems that β-carotene and vitamin E supplementation, as well as high doses of vitamin A actually increase the mortality in adults. However, although the indiscriminate supplementation with high doses of vitamin E cannot be recommended to the general public, specific groups of patients may benefit from this kind of treatment. Therefore, reliable biomarkers for detection of oxidative damage are needed. The aim of our study was to evaluate some of the methods widely used for assessment of plasma oxidative status in both clinical and experimental studies. Plasma samples from patients on chronic hemodialysis, both before and after the single hemodialysis treatment, and from healthy volunteers were used for analysis. Our results showed lack of specificity of currently used oxidative stress biomarkers, sometimes leading to different conclusions for the same set of biological samples.

Item Type: Conference or Workshop Item (Poster)
Subjects: Medical and Health Sciences > Basic medicine
Medical and Health Sciences > Clinical medicine
Divisions: Faculty of Medical Science
Depositing User: Tatjana Ruskovska
Date Deposited: 26 Dec 2012 14:31
Last Modified: 26 Dec 2012 14:31
URI: http://eprints.ugd.edu.mk/id/eprint/4283

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