Interestingly, XO has been identified to never hide its identity involving in upregulating the oxidative stress in setting of heart failure, chronic kidney disease as well as in a variety of pathophysiological circumstances 8-12, 15-17, resulting in damage of myocardium, renal tubular cells/podocytes, kidney parenchyma, endothelial cells and mitochondria 13, ultimately causing renal failure and failing of myocardium through increased renal interstitial and myocardial fibrosis 9, 14, 15. Here, XDH is linked to heart failure.