BERKELEY, CA (UroToday.com) - Our review illustrates the power of the Internet in bringing together authorities in diverse locations to put together a cohesive treatise on erectile hydraulics. The major factor causing inflow of blood into the penis is nitric oxide (NO), which is influenced by many lifestyle factors linked to cardiovascular diseases. In a prior review in the American Journal of Cardiology we outlined the relationship of erectile dysfunction (ED) to vascular disease. We used the analogy of ED being “the canary in the coal mine”, as it can sometimes be the first indication of vascular dysfunction. Our senior author, Lou Ignarro, and Bud Burnett, our second author, have been instrumental in defining NO’s role in erectile function. I found it particularly interesting that Bud’s recent research has shown that cyclic adenosine monophosphate (cyclic AMP), which is raised by caffeine, enhances the extended production of neural nitric oxide. A cup of coffee with that chocolate desert may be a further enhancer for the bedroom after a romantic meal with your sweetheart! And don’t forget the salmon for the main course. Omega-3s have multiple actions in increasing NO by direct endothelial stimulation, by decreasing vasoconstricting prostanoids, and by decreasing inflammation and oxidative stress. As in previous reviews, we have stressed that the phosphodiesterase (PDE) -5 inhibitors stimulate endogenous antioxidant protection and nitric oxide levels in addition to their widely-recognized enhancement of cyclic guanosine monophosphate (GMP) levels through inhibiting its breakdown.
Another co-author, Grace Dorey from Bristol, U.K., published one of the most well-designed studies I have read. It did not get the recognition it deserved by being published in a British journal of general practice and should have appeared in a top urology journal. Grace documented a similar benefit of pelvic floor exercises on ED as had been seen with sildenafil. Aging and lack of physical activity are the most important factors in causing ED. We have presented anatomic information supporting the concept that poor function of the pelvic floor muscles accompanying aging and a less active life style is a key factor in the decline of erectile health. Maximal erectile rigidity requires intra-corporeal pressures well in excess of systolic blood pressure that can only be explained by the muscular action of the pelvic floor. The good news is that factors influencing inflow and impeding outflow are complementary. Working on both ends of this hydraulic system will logically achieve the best results.
Bud Burnett’s main interest has been the ED that follows penile nerve injury occurring with radical prostate surgery. The fascinating thing Bud has discovered in an animal model is that paradoxically, blocking NO production improves erectile function following nerve injury. It seems highly likely that aberrant NO production, resulting in release of highly toxic NO metabolites such as peroxynitrite, is responsible for the neural dysfunction. That insight could be crucial for the development of new approaches to preservation of penile function following nerve injury.
Katherine Esposito and her group from Italy have done some of the best studies on the effects of obesity and metabolic diseases in causing ED. For readers interested in a more detailed discussion of metabolic factors, please see our review in the International Journal of Impotence Research. As we are all aware, inflammation has major adverse effects on cardiovascular health and we have outlined convincing proof that inflammation, even with a common condition of aging such as gingivitis, is a significant player in ED and as well as cardiovascular disease.
One of the most striking observations in the studies reviewed is that each of the factors described to influence erectile function acts through multiple possible mechanisms, making it difficult to conclude that one specific pathway is of greatest importance. For example, exercise directly stimulates endothelial NO production (with ED, penile-specific exercise being of greatest importance), but also improves insulin sensitivity (insulin stimulates NO), reduces oxidative stress, and likely strengthens the pelvic floor muscles. Obesity acts through increased inflammation, reduced insulin sensitivity, and increased oxidative stress. Even the PDE-5 inhibitors dramatically increase endogenous antioxidant protection, increase NO, and have favorable effects on penile smooth muscle and fibrosis. They may also improve erectile function through increasing penile-specific exercise, in addition to their effects in directly inducing penile smooth muscle relaxation by preserving levels of cyclic GMP. However, if one were to choose the factor that seems to be most important it would be oxidative stress, which is the end result of many ED-enhancing effects, including inflammation. Oxidative stress is the most important factor in aging, with aging having the greatest impact on erectile function and the incidence of ED. Due to its unbalanced electrons, NO lasts for only a few seconds in tissues and requires extensive antioxidant protection to have its favorable effects.
The most difficult issue is the complexity involved with all that we have discussed. It is simply impossible for any medical practitioner to spend the time with a patient that would be necessary to launch a comprehensive treatment of ED. That is why I have been involved in an expensive hobby in making this information available online so that men can benefit from all of the knowledge that has been accumulated. For those interested in providing such help to their patients, please see www.erectile-function.com.
The gathering together and interpretation of extensive published information, the world-wide collaboration, and the online self-help material that I have provided would simply not have been possible without the information technology revolution. The literature search that is possible through an online university library and working with a fast computer and Internet connection is incredible, and many of those papers contained information whose importance the authors had not fully appreciated. To be able to have manuscript drafts immediately available to colleagues across the ocean within seconds provides opportunities for collaboration that are mind-boggling. I hope that our work, just as does this web site quoting our review, provides a model illustrating the power of the IT revolution in improving patients’ access to the best available approaches to their health issues.
Related Reading:
- Lifestyle and metabolic approaches to maximizing erectile and vascular health
- The link between erectile and cardiovascular health: The canary in the coal mine
Written by:
David R. Meldrum, MD as part of Beyond the Abstract on UroToday.com. This initiative offers a method of publishing for the professional urology community. Authors are given an opportunity to expand on the circumstances, limitations etc... of their research by referencing the published abstract.
Department of Obstetrics and Gynecology, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, CA, USA
Erectile hydraulics: maximizing inflow while minimizing outflow - Abstract