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Disease Markers
Volume 2014, Article ID 485917, 8 pages
http://dx.doi.org/10.1155/2014/485917
Research Article

Levels of Human Erythrocyte Membrane-Bound and Cytosolic Glycohydrolases Are Associated with Oxidative Stress in Erectile Dysfunction Patients

1Department of Biomedical, Surgical and Dental Sciences, University of Milan, School of Medicine, Via Saldini 50, 20133 Milan, Italy
2Department of Health’s Sciences, University of Milan, Milan, Italy
3U.O. Andrology, San Paolo University Hospital, Milan, Italy
4IRCCS Policlinico San Donato, San Donato Milanese, Italy

Received 15 May 2014; Revised 13 July 2014; Accepted 14 July 2014; Published 5 August 2014

Academic Editor: Stamatios Theocharis

Copyright © 2014 L. Massaccesi 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.

Abstract

Oxidative stress (OS) and production of NO, by endothelium nitric oxide synthetase (eNOS), are involved in the pathophysiology of erectile dysfunction (ED). Moreover, OS induces modifications of the physicochemical properties of erythrocyte (RBC) plasma membranes and of the enzyme content of the same membranes. Due to their role in signalling early membrane alterations in OS-related pathologies, several plasma membrane and cytosolic glycohydrolases of human RBC have been proposed as new markers of cellular OS. In RBC, NOS can be activated and deactivated by phosphorylation/glycosylation. In this regulatory mechanism O-β-N-AcetylGlucosaminidase is a key enzyme. Cellular levels of O-GlcNAcylated proteins are related to OS; consequently dysfunctional eNOS O-GlcNAcylation seems to have a crucial role in ED. To elucidate the possible association between RBC glycohydrolases and OS, plasma hydroperoxides and antioxidant total defenses (Lag-time), cytosolic O-β-N-AcetylGlucosaminidase, cytosolic and membrane Hexosaminidase, membrane β-D-Glucuronidase, and α-D-Glucosidase have been studied in 39 ED patients and 30 controls. In ED subjects hydroperoxides and plasma membrane glycohydrolases activities are significantly increased whereas Lag-time values and cytosolic glycohydrolases activities are significantly decreased. These data confirm the strong OS status in ED patients, the role of the studied glycohydrolases as early OS biomarker and suggest their possible use as specific marker of ED patients, particularly in those undergoing nutritional/pharmacological antioxidant therapy.