In medicine, erectile dysfunction is defined as “lack of man’s ability to obtain or maintain hard erection sufficient for sexual intercourse”. The erection of the penis requires orchestrated operation of vascular, nervous and hormonal region. The message of sexual stimulation triggered by the brain is transmitted through the spinal cord to nerve endings that reach the corpora cavernosa – spongy consistency of structures to fill with blood causing the penis erection.
When receiving the message, endothelial cells (lining of the inner wall of the arteries) of the penile arteries release neurotransmitters which will relax the smooth muscle of the blood vessels supplying the corpus cavernosum, facilitating their filling.
Chief among these is the neurotransmitter nitric oxide. The accumulation of this substance facilitates the relaxation of the trabeculae which constitute the corpora cavernosa to increase the inflow of blood. Most drugs used for treatment of erectile dysfunction, exerts its action by increasing concentrations of dopamine in the vessels of the penis.
As men do not like to admit they suffer from erectile dysfunction, it is not always easy to estimate the prevalence of the problem. In one of the most respected studies on the subject, the Massachusetts Male Aging Study, conducted with 1290 men between 40 and 70 years, it was shown that 52% had some degree of dysfunction and 10% had complete absence of erection.
The erectile dysfunction can be classified as psychogenic, organic or mixed. The organic cause can be of vascular origin, neurogenic, hormonal, and drug-induced or be associated with anatomical changes in the corpus cavernosum.
Contrary to what many think, the organic causes are the most common: they are about 80% of cases. Important among them are vascular causes:
It is the most common of all causes. In the mechanism of formation of atherosclerotic plaques occurs to induce endothelial injury with consequent reduction of the internal diameter of the vessel and difficulty maintaining blood flow. Aging also changes the endothelium nitric oxide levels, damaging the blood into the corpora cavernosa.
Smoking for many years is one of the biggest risk factors for the development of erectile dysfunction vascular cause. Toxic substances present in cigarette cause damage to the endothelium and reduce the levels of nitric oxide in the penis. In addition, nicotine itself causes contraction of smooth muscles of blood vessels that irrigate the corpora cavernosa, reducing the blood supply to the site.
In the Massachusetts Male Aging Study, 28% of diabetic patients had erectile dysfunction, compared to 9.6% of non-diabetics (prevalence three times). The causes are linked to more accelerated atherosclerosis, changes in the tissues of the corpora cavernosa and diabetic neuropathy.
It is a major cause of erectile dysfunction as American study cited above made clear. Would it be caused by hypertension itself or was related to the anti-hypertensive medication? This controversy was clarified by a recent study: both drugs as hypertension itself can be held responsible for erection difficulties.
The presence of high blood levels of LDL-cholesterol, triglycerides and fibrinogen are associated with erectile dysfunction in both smokers and non-smokers.
The listing above shows that the factors erectile dysfunction and cardiovascular diseases share similar risk factors. Erection difficulty may be the first symptom of coronary disease, since both are linked to impairment of the endothelium, an essential framework for the regulation of the circulatory functions.
Since the risk factors mentioned act synergistically on the vascular endothelium, the extent and severity of cardiovascular involvement is often proportional to the degree of difficulty of erection.