It is meanwhile well established that both entities ED and CVD are quite often manifested in the same patient because of their common ground namely endothelial dysfunction . The pro-erectile NO-cGMP pathway and its counterpart the anti-erectile RhoA/Rho-kinase calcium sensitizing pathway are the two major players in the regulation of cavernosal smooth muscle tone and thus of erectile function.Just recently was shown that PDE 5 inhibitors (here sildenafil) show a potent relaxant effect in penile resistance arteries due to cGMP accumulation and enhanced effects of basal released endothelial NO which acts through proteinkinase G activation. There is a body of evidence in the recent literature that PDE 5 inhibition, either with the established PDE 5 inhibitors sildenafil and tadalafil or with the new PDE 5 inhibitor udenafil results in improvement of endothelial function and may also have cardioprotective properties. Recent clinical studies were able to show that with low-dose chronic application of the long acting PDE 5 inhibitor tadalafil the same effects in terms of improvement of erectile dysfunction were reached as it was shown with higher doses in as needed dose regimens.Moreover chronic PDE 5 inhibition through tadalafil was able to convert non-responders to pr regimens to responders after daily dosing for 3 months in the majority of the population under investigation. These clinical experiences along with the basic research data mentioned above are nourishing the speculations that chronic PDE 5 inhibition improves endothelial function on a long-term and thus presumably our cardiovascular system too, including cavernosal function. In addition, just recently was published that oral Rho-kinase inhibitors are able to prevent vasculogenic ED in rats. This observations justify the speculation that in the future this very novel class of compounds may add to the medicinal management of ED and perhaps of other cardiovascular diseases.
Conflict of Interest: Speaker,Study Investigator And Consultant For The Following Companies: Bayer Healthcare, Pfizer Corp., Lilly/Icos, Johnson&Johnson
Financial Support/Funding: None disclosed
Sydney Australia, April 2007
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