Oxidant-Dependent and Oxidant-Independent Proangiogenic and Vasomotor Signaling in Coronary Vascular Endothelium

Depending on their levels, source of generation, and subcellular locations, reactive oxygen species (ROS) are known to have paradoxical effects on coronary vascular endothelium. At low concentrations, ROS contribute to physiological signaling pathways that regulate vascular endothelial cell (EC) growth and survival. At higher concentrations, or with prolonged exposure, ROS can exacerbate endothelial cell injury and trigger apoptosis. In this chapter, oxidant-dependent and oxidant-independent angiogenic and vasomotor signaling pathways will be discussed in-depth, including the structures of oxidant-producing enzymes, their agonists, and their related signaling pathways in EC. Vascular endothelial growth factor (VEGF), a major growth factor involved in the maintenance of EC health, vasomotor tone, and angiogenesis, will also be discussed. VEGF utilizes both reactive oxygen species (ROS)-dependent and ROS-independent arms of EC signaling.