PL 08. The link between erectile dysfunction and lower urinary tract symptoms

Community-based and clinical data demonstrate a strong and consistent association between lower urinary tract symptoms (LUTS) and erectile dysfunction (ED), suggesting that elderly men should be evaluated for ED and vice-versa.

Pathophysiologic hypotheses regarding common basics of LUTS and ED are (1) alteration of the nitric oxide (NO)- cyclic guanosine monophosphate (cGMP) pathway, (2) enhancement of EhoA-Rho-kinase (ROCK) contractile signaling, (3) autonomic adrenergic hyperactivity and (4) pelvic atherosclerosis. Nevertheless at the present time common pathophysiology of LUTS and ED is still speculative and deserves further research.

The observation that PDE5 is expressed in human LUT tissues is in support of the hypothesis suggesting that PDE5 isoenzyme is involved in the control of the normal function of the urinary bladder, prostate, and urethra by regulating the degradation of cyclic GMP, thereby limiting the NO/cyclic GMP signaling. PDE5 inhibition results in smooth muscle relaxation and increased pelvic blood perfusion in these tissues and may modulate afferent nerve activity. Overall, this activity may affect the non-vascular or vascular smooth muscle tone. Studies have examined PDE5-inhibitors as treatment of BPH-LUTS. They have consistently reported an improvement in BPH-LUTS, irrespective of a significant Qmax improvement or the presence of ED. Overall, these findings indicate that blocking the activity of the PDE5 represents a therapeutic option to target dysfunctions of LUT tissues and ameliorate LUTS.