A randomised, placebo-controlled study to assess the efficacy of twice-daily vardenafil in the treatment of lower urinary tract symptoms secondary to benign prostatic hyperplasia. Eur Urol. 2008;53:1236-1244. [PMID: 18281145 DOI: 10.1016/j.eururo.2008.01.075]

Detrusor myocyte activity and afferent signaling

AIMS

To discuss (1) mechanisms involved in the generation and control of myocyte contractions and consequent afferent nerve activity and (2) these mechanisms as targets for drugs aimed for treatment of overactive bladder (OAB) symptoms and detrusor overactivity (DO).

METHODS

Literature review of myocyte activation, bladder afferent nerves, mediators in the bladder, and translational aspects of the findings.

RESULTS

During bladder filling, there is normally no parasympathetic outflow from the spinal cord. Despite this, the bladder develops tone during filling and also exhibits non-synchronized local contractions and relaxations that are caused by a basal myogenic mechanical activity that may be reinforced by release of, for example, acetylcholine from non-neuronal and/or neuronal sources or local mediators, such as prostaglandins and endothelins. It is suggested that these spontaneous contractions are able to generate activity in afferent nerves ("afferent noise") that may contribute to DO and OAB.

CONCLUSIONS

Spontaneous bladder myocyte contractions and factors that are able to modulate them, as well as the consequent afferent nerve activity, may be targets for drugs meant for treatment of OAB/DO.

Effects of tadalafil on lower urinary tract symptoms secondary to benign prostatic hyperplasia in men with or without erectile dysfunction

OBJECTIVES

To compare the safety and efficacy of the daily erectogenic therapy, tadalafil, on lower urinary tract symptoms secondary to benign prostatic hyperplasia (BPH-LUTS) in men with or without comorbid erectile dysfunction (ED).

METHODS

Following a 4-week placebo run-in period, men with moderate-to-severe BPH-LUTS were randomized to placebo or tadalafil 2.5, 5, 10, or 20 mg once daily for 12 weeks. International Prostate Symptom Scores (IPSS), IPSS quality of life, and BPH Impact Index were measured every 4 weeks. Safety was mainly assessed via spontaneous reports of adverse events. Data from men with (n=716) or without (n=340) ED at baseline were compared in posthoc analyses.

RESULTS

Men with ED were older and had more frequent hypertension, hyperlipidemia, coronary artery disease, and diabetes at baseline compared with men without ED. After 12 weeks, changes in IPSS in men with ED (least squares mean change from baseline, placebo: -2.4; tadalafil 2.5, 5, 10, 20 mg: -4.3, -4.8, -5.3, -5.6) and without ED (-2.4, -3.2, -5.3, -5.1, -4.5) were not significantly different (subgroup/interaction P values: .352/.644). Similar effects were observed for IPSS quality of life (with ED: -0.6, -0.9, -0.9, -1.0, -1.1; without ED: -0.6, -0.7, -0.9, -0.8, -0.8; 0.090/0.773) and BPH Impact Index (with ED: -0.7, -0.9, -1.3, -1.3, -1.4; without ED: -1.0, -0.7, -1.3, -1.3, -1.2; 0.753/0.852). Tadalafil was generally well tolerated, and men with or without ED had similar tolerability profiles.

CONCLUSIONS

Changes in BPH-LUTS after 12 weeks of treatment with placebo or various doses of once daily tadalafil were similar in men with or without comorbid ED.

Recent advances in management of bladder overactivity

Pharmacologic therapies, primarily antimuscarinic agents, have been the mainstay of treatment for overactive bladder. These drugs produce variable efficacy, a moderate rate of side effects, and rare occurrences of cure. The search for newer and better formulations and derivatives of this class of medication as well as novel therapies is ongoing and primarily fueled by the high prevalence of overactive bladder and the tremendous number of health care dollars spent on current therapy. Surgical options for overactive bladder have evolved slowly and are currently reserved for medical treatment failures and drug intolerance. This article will highlight the new drugs and therapies brought into clinical use for the treatment of overactive bladder over the last few years as well as a promising new agent in the advanced stages of development.

Urodynamic effects of once daily tadalafil in men with lower urinary tract symptoms secondary to clinical benign prostatic hyperplasia: a randomized, placebo controlled 12-week clinical trial

PURPOSE

We explored the impact of once daily tadalafil on urodynamic measures in men with lower urinary tract symptoms secondary to clinical benign prostatic hyperplasia via invasive and noninvasive urodynamic studies.

MATERIALS AND METHODS

We conducted a multicenter, randomized, double blind, placebo controlled clinical trial comparing once daily tadalafil 20 mg vs placebo during 12 weeks in men with lower urinary tract symptoms secondary to clinical benign prostatic hyperplasia with or without bladder outlet obstruction. Invasive and noninvasive urodynamics, International Prostate Symptom Score and general safety were assessed. The primary study end point was change in detrusor pressure at maximum urinary flow rate.

RESULTS

Urodynamic measures remained largely unchanged during the study with no statistically significant or clinically adverse difference between tadalafil and placebo in change in detrusor pressure at maximum urinary flow rate (mean difference between treatments -2.2 cm H(2)O, p = 0.33) or any other urodynamic parameter assessed including maximum urinary flow rate, maximum detrusor pressure, bladder outlet obstruction index or bladder capacity (all measures p > or = 0.13). Treatment with tadalafil resulted in significant improvements in International Prostate Symptom Score (mean difference between treatments -4.2, p < 0.001). Tadalafil was generally well tolerated with the majority of adverse events being mild to moderate in severity and few patients discontinuing due to adverse events (tadalafil 2.0%, placebo 1.0%).

CONCLUSIONS

Treatment with tadalafil once daily for lower urinary tract symptoms secondary to clinical benign prostatic hyperplasia showed no negative impact on bladder function as measured by detrusor pressure at maximum urinary flow rate or on any other urodynamic parameter assessed. Nonetheless men receiving tadalafil reported significant improvements in International Prostate Symptom Score with an adverse events profile similar to other recent studies of tadalafil for lower urinary tract symptoms secondary to clinical benign prostatic hyperplasia.

Therapeutic options in the treatment of benign prostatic hyperplasia

Current theraputic options for the treatment of symptomatic benign prostatic hyperplasia (BPH) are reviewed. Therapeutic options for mild lower urinary tract symptoms (LUTS), as defined by the American Urological Association, are generally treated medically. Moderate to severe LUTS can be treated medically or with surgical therapy. Current medical and surgical treatments for LUTS secondary to BPH are reviewed and evolving treatments are explored.

Sildenafil citrate and tamsulosin combination is not superior to monotherapy in treating lower urinary tract symptoms and erectile dysfunction

PURPOSE

To evaluate the efficacy of sildenafil citrate only, 25 mg. Four times/week, tamsulosin only, 0.4 mg once daily, and the combination of both on lower urinary tract symptoms (LUTS) suggestive of benign prostate hyperplasia (BPH) and erectile dysfunction.

METHODS

A total of 60 men with BPH-related LUTS were randomized to receive sildenafil citrate only (n = 20), tamsulosin only (n = 20), and the combination of both (n = 20) for 8 weeks. Changes from baseline in International Prostate Symptom Score (IPSS), maximum urinary flow rate (Q (max)), post voiding residual urine volume (PRV), Sexual Health Inventory for Male (SHIM) score, 3rd and 4th questions of International Index of Erectile Function (IIEF) were assessed at the end of the treatment.

RESULTS

The mean age was 58 years. IPSS, Q (max), PRV, SHIM scores, and 3rd and 4th questions in IIEF significantly improved in each group. Improvement of IPSS was more remarkable in combination (40.1%) and tamsulosin only (36.2%) groups in comparison with sildenafil citrate only group (28.2%; p < 0.001). Improvement of Q (max) and PRV were greater in tamsulosin only and combination than sildenafil citrate only group. SHIM scores significantly improved in sildenafil citrate only (65%) and combination (67.4%) than tamsulosin only (12.4%; p < 0.001). Increases in the 3rd and 4th questions of IIEF were greater in sildenafil only and combination than tamsulosin only (p < 0.001).

CONCLUSIONS

Treatment with the combination of tamsulosin only and sildenafil citrate only was not superior to tamsulosin only to enhance voiding symptoms. Also, sexual function improvement was similar for both the combination and sildenafil citrate only treatments.

Pharmacological management of benign prostatic hypertrophy with phosphodiesterase-5 inhibitors

Benign prostatic hypertrophy (BPH) and its associated lower urinary-tract symptoms (LUTS) commonly result in a significant decrease in the quality of life (QOL) of aging men. Although several safe and effective medications are currently available for the management of this disease, newly emerging research has focused on the exploration of unconventional pharmacological therapy. In particular, multiple clinical trials published within the past two years have explored the use of phosphodiesterase-5 (PDE-5) inhibitors for the alleviation of LUTS secondary to BPH. Although this class of medication has traditionally been used in men with erectile dysfunction (ED), the preliminary results from these studies have offered promising evidence for use of PDE-5 inhibitors in BPH.

[Significance of phosphodiesterase isoenzymes in the control of human detrusor smooth muscle function. An immunohistochemical and functional study]

OBJECTIVES

The use of inhibitors of phosphodiesterase (PDE) isoenzymes 1 and 5 to treat overactive bladder has been suggested. To further evaluate the significance of PDE isoenzymes in detrusor smooth muscle relaxation, we investigated the effects of selective PDE inhibitors on the tension induced by carbachol of isolated human detrusor tissue. Using immunohistochemical methods, the expression of PDE1, PDE4, and PDE5 in human detrusor was also investigated.

MATERIAL AND METHODS

The expression of PDE1, PDE4, and PDE5 was evaluated by means of conventional immunohistochemistry (IHC). Using the organ bath technique, the effects of the PDE inhibitors vinpocetine, rolipram, sildenafil, tadalafil, and vardenafil on the tension induced by the muscarinic agonist carbachol (1 microM) were investigated.

RESULTS

The tension induced by carbachol was dose-dependently reversed by the PDE inhibitors; the maximum reversal of tension ranged from 7% (tadalafil) to 34% (vardenafil). IHC revealed that the expression of PDE isoenzymes was limited to the smooth musculature of the detrusor. While there was prominent expression of PDE4 and PDE5, immunoreactions indicating the presence of PDE1 were less abundant.

CONCLUSION

Despite the fact that inhibitors of PDE1, PDE4, and PDE5 exerted only a weak relaxant response on detrusor strips precontracted by carbachol, our findings indicate that both the cAMP and cGMP pathways might be involved in the relaxation mechanism of human detrusor smooth muscle.

Characterization of phosphodiesterase type 5 expression and functional activity in the human male lower urinary tract

INTRODUCTION

Phosphodiesterase type 5 (PDE5) inhibitors ameliorate low urinary tract (LUT) symptoms in men with ED and symptomatic benign prostatic hyperplasia (BPH). PDE5 is highly expressed in rat and human bladder, where it regulates cyclic guanosine monophosphate (cGMP) degradation, muscle tone, and proliferation.

AIM

To investigate PDE5 tissue distribution and activity in human LUT tissues (urethra, prostate, and bladder).

MAIN OUTCOME MEASURES

PDE5 expression and activity were analyzed and compared within the same BPH patient in LUT tissues and in smooth muscle cells (SMCs) cultured from urethra, prostate, and bladder.

METHODS

In LUT tissues, PDE5 was localized by immunohistochemistry and mRNA expression by quantitative real-time polymerase chain reaction. Proliferation assay was used as readout of PDE5 activity, evaluated as ability of vardenafil to increase the antiproliferative effect of different nitric oxide (NO)/cGMP pathway activators [the PDE5-resistant cGMP analog Sp-8-Br-PET-cGMPS, the NO donor sodium nitroprusside (SNP), and the soluble guanylate cyclase (sGC) stimulator BAY 41-8543].

RESULTS

In all the LUT tissues, PDE5 was immunolocalized in blood vessels and in muscular fibres, but not in epithelium. PDE5 mRNA expression was higher in urethra and bladder than in prostate SMC. The antiproliferative effect of Sp-8-Br-PET-cGMPS was similar in all LUT SMC. In prostatic SMC, SNP and BAY 41-8543 show a dose-dependent antiproliferative effect that resulted marginally enhanced by vardenafil. Conversely, in urethra and bladder SMC the antiproliferative effect of SNP and BAY 41-8543 was lower than in prostatic SMC, but it was significantly enhanced by vardenafil. In urethral and bladder cells vardenafil half-maximal response inhibiting concentration was in the subnanomolar range, whereas in prostate cells it resulted significantly higher.

CONCLUSIONS

The highest expression and biological activity of PDE5 was found in bladder. However, a consistent PDE5 expression and activity was also found in prostatic urethra. In contrast, the prostate gland showed the lowest PDE5 abundance and cultures derived from this tissue were less sensitive to vardenafil.

Changes in peak urinary flow and voiding efficiency in men with signs and symptoms of benign prostatic hyperplasia during once daily tadalafil treatment

OBJECTIVE

To determine, by post hoc analysis, the effects of tadalafil (a long-acting phosphodiesterase 5 inhibitor) on peak urinary flow (Q(max)), bladder capacity, voiding efficiency and the obstructive symptoms of benign prostatic hyperplasia (BPH) in men with lower urinary tract symptoms secondary to BPH (BPH-LUTS), compared with placebo.

PATIENTS AND METHODS

After a 4-week placebo run-in period, 1058 men with BPH-LUTS were randomly allocated to receive once daily treatment with placebo or tadalafil (2.5, 5, 10, or 20 mg) for 12 weeks. Uroflowmetry, postvoid residual volume (PVR), and BPH symptom score measurements were assessed throughout the trial.

RESULTS

Increases in Q(max) were numerically greater for tadalafil (2.5, 5, 10, and 20 mg with percentage changes of 15%, 16%, 17%, 22%, respectively) vs placebo (12%), but did not reach statistical significance. Age, baseline Q(max), erectile dysfunction history, sexual activity, and previous alpha-blocker therapy significantly influenced the Q(max) response. Tadalafil was not associated with significant changes in PVR. Tadalafil had its greatest effects on bladder capacity and voiding efficiency in men with a Q(max) of <10 mL/s at baseline, but these changes were not significantly different from placebo responses. Tadalafil treatment significantly improved the IPSS obstructive subscores (tadalafil 2.5, 5, 10, 20 mg with percentage changes of 24%, 31%, 33%, 33%, respectively) vs placebo (13%).

CONCLUSIONS

Once daily tadalafil did not significantly change Q(max) or voiding efficiency compared with placebo in men with BPH-LUTS, although there were dose-dependent improvements. No subgroups were identified where tadalafil or placebo treatment had a deleterious effect on Q(max). Despite these minimal changes in uroflowmetric measures, tadalafil was associated with clinically meaningful and statistically significant improvements in the obstructive symptoms of BPH.

Vardenafil can improve continence recovery after bilateral nerve sparing prostatectomy: results of a randomized, double blind, placebo-controlled pilot study

INTRODUCTION

Phosphodiesterase type 5 inhibitors (PDE5-I) have acquired an established role in the treatment of post-prostatectomy erectile dysfunction (ED). Several trials in men with ED and lower urinary tract symptoms associated with benign prostatic hyperplasia suggest that PDE5-I could improve both erectile function and urinary symptoms.

AIM

To assess the role of vardenafil in continence recovery after bilateral nerve sparing radical prostatectomy (BNS-RP).

METHODS

Thirty-nine patients with prostate cancer were recruited. After BNS-RP, patients were double-blinded assigned to three arms: a) vardenafil on demand; b) vardenafil nightly; and c) placebo.

MAIN OUTCOMES MEASURES

Urinary function (UF) and urinary bother (UB) of University of California-Los Angeles Prostate Cancer Index questionnaire were assessed preoperatively and at 1, 3, 6, 9, 10, and 12 months. Twelve-month outcomes were compared to 1 month with a t-test. The differences in UF and UB (at 3, 6, 9, 10, and 12 months) between the three treatment arms were calculated by an analysis of variance. With ALLFIT we estimated half-maximal recovery times (ER50) and maximal recovery (R(max)) in three groups.

RESULTS

The improvement of UF and UB between 1 and 12 months was significant in all arms except for placebo (UF: P = 0.125; UB: P = 0.089). Nightly resulted in greater UF at 3, 6, and 9 months and greater UB at 6 months compared with placebo (P = 0.042, P = 0.044 and P = 0.039); after nightly administration, patients presented higher UB than after on-demand use, 3 and 6 months postoperatively (P = 0.036 and P = 0.017). ALLFIT demonstrated a similar ER50 in all groups (2.6 months for both UF and UB) and indicated that nightly administration induced significant improvements in R(max) compared with placebo (both <0.0001).

CONCLUSIONS

Vardenafil can improve continence recovery after BNS-RP compared with placebo. The daily use of vardenafil seems to provide better continence rate, although it does not seem to influence the timing needed to achieve full continence.

Vardenafil-induced relaxation and cyclic nucleotide levels in normal and obstructed rat urinary bladder

OBJECTIVE

To study the effects of the phosphodiesterase-5 inhibitor, vardenafil, on contraction and cyclic nucleotide levels in isolated detrusor preparations with and without mucosa, from control rats and rats with partial urethral obstruction (PUO) and intact mucosa.

MATERIALS AND METHODS

Female Sprague-Dawley rats were divided into groups subjected to PUO for 14 days (six), and sham-operated control rats (12). Detrusor preparations were mounted in organ baths and effects of increasing concentrations of vardenafil (1 nm to 100 microm) assessed on carbachol-activated (1 microm) preparations, and on contractions induced by transmural activation of nerves (electrical field stimulation, EFS). Levels of cGMP and cAMP were determined using radioimmunoassays.

RESULTS

Vardenafil caused concentration-dependent relaxations of carbachol-contracted detrusor, the mean (sd) of which at 100 microm was 91 (4)% in control and 100% in PUO rats. The -log 50% inhibitory concentration (IC(50)) was 4.41 (0.08) and 4.73 (0.05) (P < 0.01), respectively. Removing the mucosa increased the relaxant effect of vardenafil at 1-10 microm (P < 0.05) although -log IC(50) values were unaffected compared to the control. The cGMP levels ( pmol/mg protein) in control preparations increased from 2.5 (0.6) to 5.0 (0.8), and from 1.4 (0.2) to 7.2 (1.3) in obstructed bladders. In mucosa-denuded preparations the cGMP content increased from 0.6 (0.1) to 1.6 (0.4) in response to vardenafil. In control rats, the levels of cAMP increased from 12.8 (2.5) to 18.9 (0.9) (P < 0.05) after vardenafil. In mucosa-denuded preparations the cAMP levels after vardenafil increased from 16.5 (2.11) to 37.8 (3.4) (P < 0.01). In PUO bladders, the tissue content of cAMP increased from 12.6 (2.4) to 20.6 (3.4) (P < 0.01). Vardenafil concentration-dependently inhibited nerve-induced contractions in all groups studied. At 100 microm 19 (3)% of the control contraction remained, vs 8 (1)% for preparations from obstructed rats, and 11 (4)% in mucosa-denuded preparations.

CONCLUSION

In normal rats, vardenafil relaxed carbachol- and inhibited EFS-induced contractions of detrusor preparations with and without urothelium, and in PUO rats with urothelium. Relaxations were accompanied by increases in both cAMP and cGMP content. It is proposed that vardenafil-induced relaxation of rat detrusor, also in obstructed and mucosa-denuded preparations, is mediated via cAMP.

PDE5 inhibitors for LUTS

To review the current literature regarding the relationship between lower urinary tract symptoms (LUTS) and erectile dysfunction (ED), and the role of phosphodiesterase-5 (PDE5) inhibitors for the treatment of LUTS. Review of recently published (1990-2009) data regarding epidemiologic and pathophysiologic mechanisms are involved in LUTS-ED, focusing on PDE5 inhibitors particularly evidenced from level 1 clinical trials. Search terms included phosphodiesterase inhibitors, nitric oxide, autonomic hyperactivity, Rho-kinase, atherosclerosis, LUTS, benign prostatic hypertrophy, and ED. Results of several epidemiologic studies show a possible causal relationship between LUTS and ED. Four possible mechanisms have been proposed to explain this association. Multiple large clinical trials have shown a benefit in LUTS after PDE5-inhibitors treatment. PDE5 inhibitors show promise as a future treatment for LUTS, either in conjunction with existing therapies or as a primary treatment.

Prospective pharmacologic therapies for the overactive bladder

Lower urinary tract symptoms (LUTS), overactive bladder syndrome (OAB) and detrusor overactivity (DO) are all conditions that can have major effects on quality of life and social functioning. Antimuscarinic drugs are first-line treatment-they often have good initial response rates, but adverse effects and decreasing efficacy cause long-term compliance problems, and alternatives are needed. The recognition of the functional contribution of the urothelium, the spontaneous myocyte activity during bladder filling, and the diversity of nerve transmitters has sparked interest in both peripheral and central modulation of LUTS/OAB/DO pathophysiology. There may be several new possibilities to treat LUTS/OAB/DO. β(3)-AR agonists (YM178), PDE 5 inhibitors (sildenafil, tadalafil, vardenafil), vitamin D analogs (elocalcitol), combinations (α(1)-AR antagonist + antimuscarinic), and drugs with a central mode of action (tramadol, aprepitant) all have Randomized controlled trial (RCT) documented efficacy. Which of these therapeutic principles will be developed to clinically useful treatments remains to be established.

Chronic treatment with a PDE5 inhibitor increases contractile force of normal bladder in rats

OBJECTIVES

We have previously shown that a phosphodiesterase 5 (PDE5) inhibitor, vardenafil, possesses bladder protective effects in bladder outlet obstruction (BOO) rats by preserving contractile force. In this study, we examined the effects of vardenafil to obtain clues for further research elucidating the mechanism of action of vardenafil on rat normal bladder.

MATERIALS AND METHODS

In all, twenty 12-week-old female Sprague-Dawley rats were divided into two equal groups: group 1, water-treated rats; and group 2, vardenafil-treated rats. Vardenafil (8 mg/kg/day) was given by drinking water. Four weeks after, vardenafil was washed out by giving water for 24-48 h, and then bladder was excised and dissected into four longitudinal strips for isometric organ bath assay. Contractile profile of bladder strips to electrical field stimulation (EFS), carbachol, and potassium chloride (KCl) was investigated.

RESULTS

Vardenafil had no effect on body and bladder weight. Contractile forces to EFS, carbachol, and KCl were all increased significantly in group 2 by chronic vardenafil treatment.

CONCLUSION

These effects were consistent with those observed in BOO rats for carbachol response, suggesting that effects of vardenafil are not limited to diseased condition, but also apply in normal condition. Chronic treatment with vardenafil increased contractile force of rat normal bladder strips.

Effects of once-daily tadalafil on erectile function in men with erectile dysfunction and signs and symptoms of benign prostatic hyperplasia

BACKGROUND

Lower urinary tract symptoms (LUTS) secondary to benign prostatic hyperplasia (BPH; BPH-LUTS) may be associated with erectile dysfunction (ED).

OBJECTIVE

To evaluate the effects of once-daily tadalafil on erectile function in men with ED and BPH-LUTS.

DESIGN, SETTING, AND PARTICIPANTS

Post hoc analysis of a phase 2-3, multinational, randomized, double-blind, placebo-controlled, parallel-group study of men with ED and moderate-to-severe LUTS secondary to BPH who reported being sexually active. In contrast to typical ED trials, no sexual activity threshold was required to participate.

INTERVENTIONS

Screening and 4-wk washout period for patients taking BPH and/or ED treatments; 4-wk placebo run-in period; then once-daily placebo or tadalafil 2.5, 5, 10, or 20 mg for 12 wk.

MEASUREMENTS

International Index of Erectile Function-Erectile Function (IIEF-EF) domain score, International Prostate Symptom Score (IPSS), peak urinary flow rate (Q(max)), and postvoid residual volume (PVR). Analyses were performed in men who reported being sexually active with a female partner and who expected to remain so throughout the study. IIEF-EF data are presented for the BPH/ED population overall and for subgroups stratified by baseline age group, body mass index, BPH-LUTS severity, prostate-specific antigen, prior alpha-blocker use, and prior ED therapy.

RESULTS AND LIMITATIONS

Overall, 581 men were included (placebo, n=115; tadalafil 2.5 mg, n=113; tadalafil 5 mg, n=117; tadalafil 10 mg, n=120; tadalafil 20 mg, n=116). IIEF-EF domain score improvements from baseline to end point with tadalafil were 5.4 (2.5 mg), 6.8 (5 mg), 7.9 (10 mg), and 8.2 (20 mg) versus 2.0 with placebo (least-squares means; all p values <0.001). IIEF-EF domain score improvements were observed with tadalafil for all subgroup analyses, with no significant differences between subgroup or subgroup-by-treatment interaction terms. IPSS improvements from baseline to end point were significantly greater for all tadalafil doses versus placebo (all p values <0.05). Changes in Q(max) and PVR were small and not clinically meaningful.

CONCLUSIONS

These data support the use of once-daily tadalafil in men with ED and BPH-LUTS.

TRIAL REGISTRATION

http://www.clinicaltrials.gov: NCT00384930.

Vardenafil modulates bladder contractility through cGMP-mediated inhibition of RhoA/Rho kinase signaling pathway in spontaneously hypertensive rats

INTRODUCTION

Phosphodiesterase type 5 inhibitors (PDE5i), the most widely used drugs for erectile dysfunction, could also improve lower urinary tract symptoms, essentially due to overactive bladder (OAB), a condition hypothesized to be a result of an increased RhoA/Rho-kinase (ROCK) signaling. Phosphorylation/inactivation of RhoA by cyclic guanosine monophosphate (cGMP)-dependent protein kinase (PKG) activity has been described in vascular smooth muscle.

AIM

The aim of this paper was to investigate whether vardenafil-induced cGMP accumulation reduces RhoA/ROCK signaling in bladder.

METHODS

Spontaneously hypertensive rats (SHRs), a strain genetically prone to develop OAB, were treated with vardenafil (10 mg/kg/day) for 2 weeks. Wistar-Kyoto rats (WKY) were used as control. In vitro experiments were performed in human bladder smooth muscle cells (hBCs).

MAIN OUTCOME MEASURES

Urodynamic parameters were registered in vivo in anesthetized WKY and SHRs. RhoA/ROCK activity in bladder was evaluated by molecular and functional studies in tissues and cells.

RESULTS

The intercontraction interval and bladder capacity, and were decreased in SHRs and restored by vardenafil. The in vitro relaxant effect of the ROCK inhibitor Y-27632 was higher in bladder strips from SHR than from WKY and reduced by vardenafil. Nomega-nitro-L-arginine-methyl-ester (a NO-synthase inhibitor, 40 mg/kg/day during the last week of the 2-week treatment with vardenafil) partially antagonized vardenafil effect on Y-27632 responsiveness. Vardenafil prevented RhoA membrane translocation/activation, decreased ROCK activity, and increased cGMP levels in vivo (rat) and in vitro (hBCs). Exposing hBCs to vardenafil increased Ser(188) RhoA phosphorylation, to the same extent as the PDE5-insensitive PKG agonist Sp-8-Br-PET-cGMP. Moreover, vardenafil inhibited several RhoA-dependent functions in hBCs, including smooth muscle gene transcription and endothelin-1-induced migration. These effects were reverted by the PKG inhibitor KT 5823, further suggesting a cGMP/PKG-dependency. In hBCs, vardenafil was active in the low nanomolar range.

CONCLUSIONS

This is the first study demonstrating that the effect of vardenafil on OAB could be partially determined by a cGMP-dependent RhoA/ROCK signaling inhibition.

Is there a rationale for the chronic use of phosphodiesterase-5 inhibitors for lower urinary tract symptoms secondary to benign prostatic hyperplasia?

OBJECTIVES

To critically review the physiological roles of phosphodiesterase-5 (PDE5), to explain and support the putative impact and clinical significance of PDE5 inhibitors (PDE5-Is) in the treatment of lower urinary tract symptoms (LUTS) associated with benign prostatic hyperplasia (BPH) and erectile dysfunction (ED), both highly prevalent in men aged > or =50 years, as PDE5-Is are very effective as a first-line therapy for ED, and attractive for further physiological functional investigations.

METHODS

We searched Medline for peer-reviewed articles in English, from 1991 to 2008, to provide a critical contemporary review of PDE5 pertaining to the potential interest of findings supporting a role for PDE5-Is in LUTS due to BPH. The selection of papers was based on the relevance of subject matter. A critical analysis of available fundamental and clinical data is reported.

RESULTS

Several studies assessed the role of the nitric oxide/cGMP signalling pathway in the regulation of the prostate tone, with the support of clinical observations. PDE5-Is can also represent a potential mode of action allowing the targeting of transcriptional activity implicated in the regulation of the progression of the inflammatory process involved in BPH. PDE5-Is can inhibit human stromal cell proliferation of the prostate mediated by cGMP accumulation. New targeting hypotheses of pathophysiological processes are also reported.

CONCLUSIONS

There is evidence that LUTS and ED are strongly linked. This analysis of the regulatory basis of PDE5 biology could indicate several directions of investigation. However, it is necessary to devise well-designed large prospective studies that would produce significant data before this approach becomes a standard of care.

Erectile dysfunction and cardiovascular disease: efficacy and safety of phosphodiesterase type 5 inhibitors in men with both conditions

Risk factors for cardiovascular disease and erectile dysfunction (ED) are similar, as might be expected given their shared etiologic and pathophysiologic origins. It is now generally accepted that most cases of ED result from a vascular disturbance of the endothelium. Recent epidemiological studies have documented a strong association between ED and comorbid conditions such as hypertension, diabetes mellitus, and dyslipidemia. Phosphodiesterase type 5 (PDE5) inhibitors are recommended as first-line therapy for erection problems of all etiologies and severities. The efficacy and safety of PDE5 inhibitors in the general ED population is well documented and has been extensively reviewed. To examine the association between ED and vascular disorders in the context of current knowledge regarding PDE5 inhibitors, an electronic search was performed of articles published from January 2002 through April 2008 using the PubMed, EMBASE, and MEDLINE databases. Although preference was given to randomized, blinded, controlled clinical trials, data from retrospective studies were also reviewed when appropriate. This analysis revealed that the clinical evidence linking ED to future cardiovascular events is compelling, presenting physicians with a unique interventional opportunity to address underlying cardiovascular health concerns in men presenting with ED. In most studies, PDE5 inhibitors were shown to effectively and safely improve erectile function regardless of cause, severity, or presence of comorbid conditions, including hypertension, diabetes mellitus, and dyslipidemia.

Erectile dysfunction and cardiovascular disease: efficacy and safety of phosphodiesterase type 5 inhibitors in men with both conditions

Risk factors for cardiovascular disease and erectile dysfunction (ED) are similar, as might be expected given their shared etiologic and pathophysiologic origins. It is now generally accepted that most cases of ED result from a vascular disturbance of the endothelium. Recent epidemiological studies have documented a strong association between ED and comorbid conditions such as hypertension, diabetes mellitus, and dyslipidemia. Phosphodiesterase type 5 (PDE5) inhibitors are recommended as first-line therapy for erection problems of all etiologies and severities. The efficacy and safety of PDE5 inhibitors in the general ED population is well documented and has been extensively reviewed. To examine the association between ED and vascular disorders in the context of current knowledge regarding PDE5 inhibitors, an electronic search was performed of articles published from January 2002 through April 2008 using the PubMed, EMBASE, and MEDLINE databases. Although preference was given to randomized, blinded, controlled clinical trials, data from retrospective studies were also reviewed when appropriate. This analysis revealed that the clinical evidence linking ED to future cardiovascular events is compelling, presenting physicians with a unique interventional opportunity to address underlying cardiovascular health concerns in men presenting with ED. In most studies, PDE5 inhibitors were shown to effectively and safely improve erectile function regardless of cause, severity, or presence of comorbid conditions, including hypertension, diabetes mellitus, and dyslipidemia.

Erectile dysfunction and lower urinary tract

During the last decades it turned out that the NO/cGMP signaling cascade is one of the most prominent regulators of a variety of physiological and pathophysiological processes in a broad range of mammalian tissues. Thus cGMP is a key second messenger and targeting this pathway by increasing intracellular cGMP levels is a very successful approach in pharmacology as shown for nitrates, PDE5 inhibitors and more recently for stimulators of the guanylate cyclase. Besides the beneficial effects of cGMP elevation in cardiac, vascular, pulmonary, renal or liver disorders the launch of PDE5 inhibitors for the treatment of erectile dysfunction 10 years ago, has directed a lot of attention to the NO/cGMP signaling in the lower urinary tract. Triggered by the use of PDE5 inhibitors in ED it turned out that cGMP is a common regulatory mechanism for lower urinary tract function also beyond ED. In recent years intense research and development efforts were undertaken to elucidate the role of the NO/cGMP and to fully exploit the therapeutic implications of cGMP elevation in urological disorders in ED and beyond. Therefore we have summarized the effects of cGMP elevation for treatment of erectile dysfunction in males and in females. We have also reviewed the recent pre-clinical and clinical lines of evidence for treatment options of benign prostatic hyperplasia and lower urinary tract symptoms in male patients and overactive bladder and urinary incontinence in female patients. In addition we also touch more speculative concepts using cGMP elevating drugs for the treatment of premature ejaculation, peyornies disease and stone disease.