Ischemia/reperfusion-induced and sepsis-induced endothelial dysfunction is initiated by increased amounts of ROS produced by the induction of enzymes such as nicotinamide adenine dinucleotide phosphate-oxidase (NOX) and uncoupling of mitochondrial oxidative phosphorylation and endothelial nitric oxide synthase (eNOS). The gene discussed is NOS3; the disease is Sepsis.