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Oxidative Medicine and Cellular Longevity
Volume 2016, Article ID 3527579, 8 pages
Review Article

Xanthine Oxidoreductase-Derived Reactive Species: Physiological and Pathological Effects

Alma Mater Studiorum-University of Bologna, Department of Experimental, Diagnostic and Specialty Medicine (DIMES), General Pathology Unit, Via S. Giacomo 14, 40126 Bologna, Italy

Received 25 September 2015; Accepted 1 November 2015

Academic Editor: Tanea T. Reed

Copyright © 2016 Maria Giulia Battelli et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Xanthine oxidoreductase (XOR) is the enzyme that catalyzes the oxidation of hypoxanthine to xanthine and xanthine to uric acid and is widely distributed among species. In addition to this housekeeping function, mammalian XOR is a physiological source of superoxide ion, hydrogen peroxide, and nitric oxide, which can function as second messengers in the activation of various pathways. This review intends to address the physiological and pathological roles of XOR-derived oxidant molecules. The cytocidal action of XOR products has been claimed in relation to tissue damage, in particular damage induced by hypoxia and ischemia. Attempts to exploit this activity to eliminate unwanted cells via the construction of conjugates have also been reported. Moreover, different aspects of XOR activity related to phlogosis, endothelial activation, leukocyte activation, and vascular tone regulation, have been taken into consideration. Finally, the positive and negative outcomes concerning cancer pathology have been analyzed because XOR products may induce mutagenesis, cell proliferation, and tumor progression, but they are also associated with apoptosis and cell differentiation. In conclusion, XOR activity generates free radicals and other oxidant reactive species that may result in either harmful or beneficial outcomes.