Release of ROS, due to the stimulation and upregulation of ROS-producing enzymes, such as nicotinamide adenine dinucleotide phosphate oxidase 4 (NOX4) and inducible Nitric Oxide synthase (iNOS) [196], is an additional hallmark of aneurysm development and contributes to a variety of pathological VSMC states, including inflammation and apoptosis [197]. Here, NOS2 is linked to aneurysm.