Oxidants are produced endogenously and can react with and thereby post-translationally modify target
proteins. They have been implicated in the redox regulation of signal transduction pathways conferring protection, but also in mediating oxidative stress and causing damage. The difference is that in scenarios of injury the amount of
oxidants generated is higher and/or the duration of
oxidant exposure sustained. In the cardiovascular system,
oxidants are important for blood pressure homeostasis, for unperturbed cardiac function and also contribute to the observed protection during ischemic preconditioning. In contrast, oxidative stress accompanies all major cardiovascular pathologies and has been attributed to mediate contractile dysfunction in part by inducing oxidative modifications in myofilament
proteins. However, the proportion to which oxidative modifications of
contractile proteins are beneficial or causatively mediate
disease progression needs to be carefully reconsidered. These antithetical aspects will be discussed in this review with special focus on direct oxidative post-translational modifications of myofilament
proteins that have been described to occur in vivo and to regulate actin-
myosin interactions in the cardiac myocyte sarcomere, the methodologies for detection of oxidative post-translational modifications in target
proteins and the feasibility of
antioxidant therapy strategies as a potential treatment for
cardiac disorders.