Endothelial dysfunction and erectile dysfunction in the aging man

Penile erection is a vascular event that requires an intact endothelium to occur. A dysfunctional endothelium is an early marker for the development of atherosclerotic changes and can also contribute to the occurrence of acute cardiovascular events. The pathogenesis of both endothelial and erectile dysfunction (ED) is intimately linked through decreased expression and activation of endothelial nitric oxide (NO) synthase, and the subsequent blunted physiological actions of NO naturally occurring with aging. It is now well-understood that ED is a symptom of underlying disease rather than a disease itself; for this reason in the near future both general practitioners, internal medicine practitioners and many specialists will have to interplay with sexual medicine. Aging in the man is also associated with several changes in arterial structure and function, part of them related to the decline of circulating levels of steroids, that is, testosterone and estradiol. These changes may be responsible, in part, for the lack of efficacy of ED treatments. The recent discovery that chronic administration of phosphodiesterase type 5 inhibitors may improve erectile and endothelial responsiveness of men previously non-responsive to on-demand regimes, and the knowledge that testosterone is one of the main modulators of the expression of penile phosphodiesterase type 5 isoenzyme, opens a new scenario in the treatment of men with ED and co-morbidities. The aim of this review is to discuss the pathophysiology of endothelial dysfunction and its relationship with ED in the aging male, and to suggest possible strategies to improve arterial function with regard to sexual dysfunctions.