Increased activity of NAD(P)H oxidase, inflammation, over-expression of inducible nitric oxide synthase (iNOS), iron release from hemoglobin and endothelial dysfunction resulting in uncoupled endothelial nitric oxide synthase (eNOS) are recognized to be important sources of ROS production in AAA [10,11]. The gene discussed is NOS3; the disease is endothelial dysfunction.