Aha Scientific Statement on Behalf of the American Heart Association Council on Basic Cardiovascular Sciences. Measurement of Reactive Oxygen Species, Reactive Nitrogen Species, and Redox-dependent Signaling in the Cardiovascular System: a Scientific Statement from the American Heart Association. Me

e39 Abstract—Reactive oxygen species and reactive nitrogen species are biological molecules that play important roles in cardiovascular physiology and contribute to disease initiation, progression, and severity. Because of their ephemeral nature and rapid reactivity, these species are difficult to measure directly with high accuracy and precision. In this statement, we review current methods for measuring these species and the secondary products they generate and suggest approaches for measuring redox status, oxidative stress, and the production of individual reactive oxygen and nitrogen species. We discuss the strengths and limitations of different methods and the relative specificity and suitability of these methods for measuring the concentrations of reactive oxygen and reactive nitrogen species in cells, tissues, and biological fluids. We provide specific guidelines, through expert opinion, for choosing reliable and reproducible assays for different experimental and clinical situations. These guidelines are intended to help investigators and clinical researchers avoid experimental error and ensure high-quality measurements of these important biological species. *Drs Griendling and Touyz contributed equally to this work. The American Heart Association makes every effort to avoid any actual or potential conflicts of interest that may arise as a result of an outside relationship or a personal, professional, or business interest of a member of the writing panel. Specifically, all members of the writing group are required to complete and submit a Disclosure Questionnaire showing all such relationships that might be perceived as real or potential conflicts of interest. R eactive oxygen species (ROS) and reactive nitrogen species (RNS) are produced in virtually all eukaryotic cells. These molecules regulate several physiological processes including proliferation, migration, hypertrophy, differentiation, cytoskeletal dynamics, and metabolism, but when available in excess, they react with lipids, proteins, and nucleic acids, thereby altering structural and functional properties of target molecules and leading to extensive tissue dysfunction and injury. ROS and RNS have been implicated in the development of many cardiovascular diseases, including hypertension, heart failure, atherosclerosis, and cardiovascular and renal complications of diabetes mellitus. Cardiovascular injury caused by ischemia-reperfusion or exposure to environmental pollutants, tobacco smoke, and ionizing radiation has also been linked to excessive ROS or RNS accumulation. Despite extensive data implicating oxidative stress in animal models of cardiovascular disease and dysfunction, there is still no conclusive evidence that ROS/RNS are fundamentally involved in the pathogenesis of cardiovascular disease in humans, and there is a paucity of convincing evidence that antioxidants are effective therapies in cardiovascular medicine. …