Semiquantitative imaging measurement of baseline and vasomodulated normal prostatic blood flow using sildenafil

Lower urinary tract symptoms/benign prostatic hypertrophy and vascular function: Role of the nitric oxide-phosphodiesterase type 5-cyclic guanosine 3',5'-monophosphate pathway

It is well known that there is an association of lower urinary tract symptoms/benign prostatic hypertrophy with cardiovascular disease, suggesting that lower urinary tract symptoms/benign prostatic hypertrophy is a risk factor for cardiovascular events. Vascular function, including endothelial function and vascular smooth muscle function, is involved in the pathogenesis, maintenance and development of atherosclerosis, leading to cardiovascular events. Vascular dysfunction per se should also contribute to lower urinary tract symptoms/benign prostatic hypertrophy. Both lower urinary tract symptoms/benign prostatic hypertrophy and vascular dysfunction have cardiovascular risk factors, such as hypertension, dyslipidemia, diabetes mellitus, aging, obesity and smoking. Inactivation of the phosphodiesterase type 5-cyclic guanosine 3',5'-monophosphate-nitric oxide pathway causes lower urinary tract symptoms/benign prostatic hypertrophy through an enhancement of sympathetic nervous activity, endothelial dysfunction, increase in Rho-associated kinase activity and vasoconstriction, and decrease in blood flow of pelvic viscera. Both endogenous nitric oxide and exogenous nitric oxide act as vasodilators on vascular smooth muscle cells through an increase in the content of cyclic guanosine 3',5'-monophosphate, which is inactivated by phosphodiesterase type 5. In a clinical setting, phosphodiesterase type 5 inhibitors are widely used in patients with lower urinary tract symptoms/benign prostatic hypertrophy. Phosphodiesterase type 5 inhibitors might have beneficial effects on vascular function through not only inhibition of cyclic guanosine 3',5'-monophosphate degradation, but also increases in testosterone levels and nitric oxide bioavailability, increase in the number and improvement of the function of endothelial progenitor cells, and decrease in insulin resistance. In the present review, the relationships between lower urinary tract symptoms/benign prostatic hypertrophy, the phosphodiesterase type 5-nitric oxide-cyclic guanosine 3',5'-monophosphate pathway, vascular function and cardiovascular outcomes are examined.

Tadalafil for lower urinary tract symptoms secondary to benign prostatic hyperplasia: a review of clinical data in Asian men and an update on the mechanism of action

Tadalafil, a phosphodiesterase type 5 (PDE5) inhibitor, is approved worldwide for the treatment of lower urinary tract symptoms secondary to benign prostatic hyperplasia (BPH-LUTS). The purpose of this narrative review is to summarize the clinical data on tadalafil 5 mg once-daily, primarily focusing on Asian men with BPH-LUTS, and to update the current understanding of the mechanism of action underlying PDE5 inhibition. Findings from studies have demonstrated that PDE5 is highly expressed in the lower urinary tract and supporting vasculature, and that PDE5 inhibition potentially decreases smooth muscle cell proliferation in the prostate, relaxes smooth muscle in the prostate, bladder neck and supporting vasculature, increases blood perfusion to the lower urinary tract, and modulates bladder afferent nerve activity. A total of 11 larger, 12-week, double-blind, randomized, placebo-controlled studies of tadalafil, including four Asian studies, have been conducted globally, enrolling >3000 men with BPH-LUTS. In addition, two long-term (42- and 52-week) studies enrolled 394 Japanese and 428 North American men, respectively, with BPH-LUTS. Overall, tadalafil 5 mg once-daily resulted in significant improvements in the change from baseline to endpoint in total International Prostate Symptom Scores (IPSS), IPSS storage and voiding subscores, and IPSS quality of life index compared with placebo. Tadalafil was well tolerated and had a favorable safety profile. These findings support tadalafil 5 mg once-daily for treating men, including Asian men, with BPH-LUTS.

Practical application of color Doppler ultrasonography in patients with ejaculatory dysfunction

We describe two cases in which dynamic analysis of ejaculation using color Doppler ultrasonography was useful in diagnosis of ejaculatory dysfunction and planning of therapy. The first patient was a 32-year-old man with a diagnosis of retrograde ejaculation. A bladder neck collagen injection was carried out, as the main cause was thought to be the bladder neck remaining open during ejaculation. The patient had antegrade ejaculation 1 week later. The second patient was a 48-year-old man with a diagnosis of anorgasmia accompanied by decreased seminal emission and insufficient function of the rhythmic pelvic striated muscles. The patient was prescribed etilefrine hydrochloride 15 mg/day. The symptom improved 2 weeks after starting this drug. These cases suggest that the use of color Doppler ultrasonography during ejaculation can improve the understanding of ejaculatory dysfunction and therapy for this condition.

Effect of tadalafil once daily on prostate blood flow and perfusion in men with lower urinary tract symptoms secondary to benign prostatic hyperplasia: a randomized, double-blind, multicenter, placebo-controlled trial

OBJECTIVE

To assess effects of tadalafil vs placebo on prostatic blood flow measured by transrectal ultrasonography in men aged ≥45 years with moderate-to-severe benign prostatic hyperplasia-lower urinary tract symptoms.

METHODS

After screening and washout, patients were randomized to placebo (n = 50) or tadalafil 5 mg (n = 47) once daily for 8 weeks. Transrectal ultrasonography was performed at baseline, 4, and 8 weeks. The primary efficacy measure was the prostate transition zone (TZ) resistive index (RI). Secondary efficacy measures were RI in the peripheral zone and bladder neck, color pixel intensity (CPI), and color pixel density (CPD) in all 3 regions. Outcomes were assessed using mixed-model repeated-measures analyses.

RESULTS

The overall treatment effect (tadalafil vs placebo) for the change from baseline through week 8 in prostate TZ RI was not statistically significant (least squares mean change: placebo, -0.01; tadalafil, 0.00; P = .118), nor was the change from baseline in prostate TZ CPI (P = .564) or CPD (P = .592). Results were similar for all flow measures in prostate peripheral zone and bladder neck. The adverse event profile was consistent with previous studies with no new safety findings.

CONCLUSION

Tadalafil for 8 weeks in men with BPH-LUTS did not result in detectable decreases in arterial RI or increases in CPI or CPD in the prostate or bladder neck. Detection of changes may not be possible because of already low baseline RI, insufficient sensitivity of techniques used, or may have been confounded by methodologic variability across sites. Alternatively, other possible mechanisms not assessed in this study may be more prominently involved.

Uroflowmetric assessment of acute effects of sildenafil on the voiding of men with erectile dysfunction and symptomatic benign prostatic hyperplasia

PURPOSE

To evaluate the acute effects of sildenafil (50 mg) on the micturation of men with erectile dysfunction (ED) and concomitant benign prostatic hyperplasia (BPH) with lower urinary tract symptoms (LUTS) using uroflowmetric parameters.

MATERIALS AND METHODS

A total of 68 male patients randomized into two groups (36 treatment, 32 control groups) with International Prostate Symptom Score (IPSS) greater than 7 and International Index of Erectile Dysfunction-erectile function domain score lower than 26 were enrolled in the study. Patients in the treatment group received a single dose of 50 mg of oral sildenafil. Patients in the control group received no treatment. Prevoiding urine volumes determined ultrasonographically and voided urine volumes were also recorded. Statistical comparisons were made with the use of analysis of variance (ANOVA).

RESULTS

Mean ages were similar between treatment and control groups (60.4 +/- 9.8 and 58.6 +/- 8.3 years, respectively, P = 0.430). In the treatment group the maximum and average flow rates increased significantly (Q (max) from 15.6 +/- 6.8 cc/s to 19.3 +/- 7.2 cc/s, P < 0.0001; Q (avg) from 7.3 +/- 3.0 cc/s to 9.1 +/- 3.0 cc/s, P < 0.0001) with sildenafil administration, while other parameters studied remained unchanged.

CONCLUSION

Despite the limitations of variations of uroflowmetry, this study showed that sildenafil improves Q (max) and Q (avg) in patients suffering from ED with concomitant BPH-LUTS. Long-term studies are needed to evaluate the effects on IPSS, side effects, and drug interactions.