,6 Expression and activation of Nox isoforms are increased in hypertension and are a likely cause of oxidative stress in cardiovascular, renal, and immune cells in hypertension-associated target organ damage.6, 7, 8 Other enzymatic sources of ROS include mitochondrial oxidases, xanthine oxidase, endoplasmic reticular oxidases, and uncoupled nitric oxide synthase (NOS). Here, XDH is linked to hypertensive disorder.