The Janus Face of Oxidative Stress in Health and Disease: the Cause or the Cure?

Reactive oxygen species (ROS), reactive nitrogen species (RNS) and diffusible reactive species (DRS), under certain concentrations, play an important role at the physiological level. The role of antioxidant molecules, endogenous and exogenous, is to maintain adequate amounts of ROS and RNS. The increase in ROS and RNS due to an overproduction of these species or a decrease in antioxidant molecules leads to the phenomenon called oxidative stress. Oxidative stress is involved in the physiological process of aging but is implicated in pathologies such as some types of tumors, neurodegenerative and autoimmune disorders, male infertility, cardiovascular disorders such as atrial fibrillation, and lung disorders such as chronic obstructive pulmonary disorders and pulmonary hypertension. This involvement has aroused widespread interest, especially because many studies try to exploit it at a therapeutic level. The purpose of this review is to discuss pathologies in which oxidative stress has an important role and for this reason, it can be targeted for a therapeutic intervention to improve or cure the pathology; sometimes modulation of oxidative stress can be used to improve the effect of the therapy.