XDH and cardiovascular disorder: Despite the preclinical and clinical evidence for an important role of oxidative stress for the development and progression of cardiovascular disease, there are, to date, only a few examples of clinical studies demonstrating that targeted antioxidant drugs (e.g., xanthine oxidase inhibitors, meta-analysis in 10,684 individuals) or tight control of vitamin C plasma levels (e.g., EPIC-Norfolk trial, 19,496 individuals [39]) improve the prognosis of patients with cardiovascular disease.