Male sexual dysfunction in diabetes mellitus

Erectile dysfunction (ED), also known as impotence, is defined as the inability to achieve or maintain an erection sufficient for satisfactory sexual function. Based on these data and the US population projection for the year 2020 of more than 74 million men 45-84 years old, ED will affect more than 38 million men and millions more over the age of 84. Diabetic men have a more than threefold increase in risk of ED compared to their nondiabetic counterparts. Diabetes mellitus (DM) is a common chronic disease affecting 285 million people and is expected to increase to 7.7% by 2030. Because both ED and DMare so prevalent, it is not surprising the two are associated. ED is reported to occur in more than 50% of men with diabetes. The penis is a complex vascular organ that requires the coordination of an initiated spinal reflex to a vascular process in which nerves, sinusoidal and vascular endothelium, and smooth muscle (SM) cells are involved to achieve satisfactory penile erection. In men with DM who have impaired erection, there is the inability to either obtain or maintain a state of penile rigidity sufficient for satisfactory intercourse. In those having DM with ED, there is a panoply of possible adverse effects on the neurological function, vascular (including smooth muscle and endothelium) supply, cell membranes, contractile proteins, and a myriad of neurotransmitters and second messengers that can interfere with the normal mechanism of erection. These potential mechanisms and modern therapies for ED are reviewed as a starting point for understanding the basis of this important physiological function.