Biomarkers of oxidative and nitro-oxidative stress: conventional and novel approaches.

The concept of oxidative stress (OS) that connects altered redox biology with various diseases was introduced 30 years ago and has generated intensive research over the past two decades. Whereas it is now commonly accepted that macromolecule oxidation in response to ROS is associated with a variety of pathologies, the emergence of NO as a key regulator of redox signalling has led to the discovery of the pathophysiological significance of reactive nitrogen species (RNS). RNS can elicit various modifications of macromolecules and lead to nitrative or nitro-OS. In order to investigate oxidative and nitro-OS in human and in live animal models, circulating biomarker assays have been developed. This article provides an overview of key biomarkers used to assess lipid peroxidation and NO/NO2 signalling, thereby stressing the necessity to analyse several OS biomarkers in relation to the overall (aerobic) metabolism and health condition of patients. In addition, the potential interest of heart rate variability as the non-invasive integrative biomarker of OS is discussed. LINKED ARTICLES: This article is part of a themed section on Redox Biology and Oxidative Stress in Health and Disease. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v174.12/issuetoc.