BIOMARKERS OF OXIDANT STRESS IN BRONCHIAL ASTHMA

Summary: Oxidant stress is believed to contribute to both the initiation and development of bronchial asthma (BA). As such, the pathophysiology of BA is characterised by the large generation of reactive oxygen spe cies (ROS) and reactive nitrogen species (RNS), predominantly by inflammatory cells of asthmatic airways. These species play an important role in remodelling airways and in orchestrating the type of inflammatory response. Oxidants influence the specific balance of Th1/Th2 cytokines, and together with Th2-cytokines and Th2 induced cells can cause many of the features typical of asthma. They induce bronchoconstriction, mucus secretion, effects on airway vasculature, and increase airway responsiveness to several agonists. This review discusses the necessity of oxidant stress evaluation in BA using reliable biomarkers, which provide an appropriate tool for studying oxidant stress. It is desirable to determine prooxidants and antioxidant systemic and local parameters in lung specific media such as bronchoalveolar lavage (BAL), sputum, exhaled air and breath condensate. These airway biomarkers may be representative indicators which could show the processes occurring on the airway surface, the initial site of oxidation. Thus, the examination of biomarkers is essential for establishing the potential target for antioxidant supplementation that would be able to normalise the oxidant/ antioxidant imbalance.