Increased corpus cavernosum smooth muscle tone associated with partial bladder outlet obstruction is mediated via Rho-kinase

Effects of eupatilin on the contractility of corpus cavernosal smooth muscle through nitric oxide-independent pathways

Eupatilin (5,7-dihydroxy-3,4,6-trimethoxyflavone) is one of the main compounds present in Artemisia species. Eupatilin has both antioxidative and anti-inflammatory properties and a relaxation effect on vascular contraction regardless of endothelial function. We evaluated the relaxant effects of eupatilin on the corpus cavernosum (CC) of rabbits and the underlying mechanisms of its activity in human corpus cavernosum smooth muscle (CCSM) cells. Isolated rabbit CC strips were mounted in an organ bath system. A conventional whole-cell patch clamp technique was used to measure activation of calcium-sensitive K⁺ -channel currents in human CCSM cells. The relaxation effect of eupatilin was evaluated by cumulative addition (10^-5  m ~ 3 × 10^-4  m) to CC strips precontracted with 10^-5  m phenylephrine. Western blotting analysis was performed to measure myosin phosphatase targeting subunit 1 (MYPT1) and protein kinase C-potentiated inhibitory protein for heterotrimeric myosin light chain phosphatase of 17-kDa (CPI-17) expression and to evaluate the effect of eupatilin on the RhoA/Rho-kinase pathway. Eupatilin effectively relaxed the phenylephrine-induced tone in the rabbit CC strips in a concentration-dependent manner with an estimated EC₅₀ value of 1.2 ± 1.6 × 10^-4  m (n = 8, p < 0.05). Iberiotoxin and tetraethylammonium significantly reduced the relaxation effect (n = 8, p < 0.001 and p = 0.003, respectively). Removal of the endothelium or the presence of L-NAME or indomethacin did not affect the relaxation effect of eupatilin. In CCSM cells, the extracellular application of eupatilin 10^-4  m significantly increased the outward currents, and the eupatilin-stimulated currents were significantly attenuated by treatment with 10^-7  m iberiotoxin (n = 13, p < 0.05). Eupatilin reduced the phosphorylation level of MYPT1 at Thr853 of MLCP and CPI-17 at Thr38. Eupatilin-induced relaxation of the CCSM cells via NO-independent pathways. The relaxation effects of eupatilin on CCSM cells were partially due to activation of BK_Ca channels and inhibition of RhoA/Rho-kinase.

Corneal Endothelial Cell Migration and Proliferation Enhanced by Rho Kinase (ROCK) Inhibitors in In Vitro and In Vivo Models

Purpose

To explore the role of Rho-associated kinases (ROCK) in corneal physiology and regeneration, and the effects of suppressing its activity in stimulating corneal endothelial cell proliferation and migration in vitro and in vivo.

Methods

Immunohistochemistry was performed to detect RhoA and ROCK-1 and ROCK-2 in human corneal tissue. Adult porcine corneal endothelial cells (CECs) were isolated, grown to confluence, and further characterized. Under the treatment of ROCK inhibitors, changes in the cellular distribution profile of ZO-1 and F-actin were examined by immunofluorescence staining. Corneal endothelial cells migration was evaluated by scratch assay and analyzed with Axiovision software. Cell proliferation was quantified using Click-iT EdU HCS Assay. In vivo, the corneal endothelia of rabbits were surgically injured and H-1152 was topically applied for 10 days. Progress of wound healing was evaluated daily by monitoring corneal edema, inflammation, and thickness using slit-lamp examination, photography, and pachymetry. Rabbits were euthanized and enucleated for further evaluation.

Results

H-1152 exhibited significant stimulatory effect on CEC migration and proliferation in vitro compared with both untreated and Y-27632–treated cells. Furthermore, topical administration of H-1152 led to marked reduction in corneal edema and formation of multinucleate CECs in vivo suggestive of proliferation associated with healing.

Conclusions

H-1152 exhibited a better stimulatory effect on CEC migration and proliferation in vitro than Y-27632. Our findings suggest that topical administration of H-1152 promotes healing of injured corneal endothelium in vivo. These results demonstrate the efficacy of ROCK inhibitors as a potential topical therapy for patients with corneal endothelial disease.

Correlation of Subjective Symptoms in Patients with Benign Prostatic Hyperplasia and Erectile Dysfunction

Introduction:

Epidemiological studies suggest a link between the symptoms of lower urinary tract (LUTS) caused by benign prostatic hyperplasia (BPH) and erectile dysfunction (ED). Increasing expected period of life, justify the interest of establishing correlations LUTS / BPH and ED in order to find more efficient ways of treating these pathologies.

Goal:

The objective was to evaluate the correlation of symptoms in LUTS/BPH with the degree of ED.

Patients and Methods:

The study was conducted as a prospective study which involved males aged 40-60 yr with present symptoms of LUTS/BPH. All study subjects underwent quantification of subjective symptoms through the International Prostate Symptom Score-IPSS and International Index of Erectile Dysfunction- IIEF-5. The first group of respondents had IPSS 0-8, second group IPSS 9-19 and the third group IPSS 20 to 35.

Results:

The results of ANOVA (F = 112.492, p = 0.000) showed that there was a statistically significant difference (p <0.05) between groups in degree of erectile function (IIEF). Tahmane test showed that there was a statistically significant difference between the first and second group (p = 0.000 <0.05), the first and third group (p = 0.000 <0.05) and the second and third group (p = 0.000 <0.05). Mean degree of ED correlates with IPSS. The results of Fisher’s exact test (p = 0.000) confirmed that there was a statistically significant relationship (p <0.05) between the IPSS score and degree of erectile dysfunction (IIEF).

Conclusion:

Elderly patients have a significantly higher value of IPSS score compared to younger patients. The degree of erectile dysfunction is correlated with symptoms of IPSS score. Severity of symptoms of LUTS/BPH and higher IPSS score, worsens the ED. Results of IIEF-5 score are inversely proportional with symptoms of IPSS score, and increase in IPSS score comes to a decline in IIEF score.

Effect of short- and long-term sildenafil treatment on erectile dysfunction in rats with partial bladder outlet obstruction

AIM

Lower urinary tract symptoms (LUTS) and erectile dysfunction (ED) are frequent problems in older men worldwide. We evaluated the effect of short- and long-term sildenafil treatment on erectile function in rats with surgically induced partial bladder outlet obstruction (PBOO).

METHODS

A total of 60 male Sprague-Dawley rats were randomized in five groups: (1) control (sham-operated); (2) PBOO for 3 weeks; (3) PBOO for 6 weeks; (4) sildenafil (1.5 mg/rat/day) treated PBOO for 3 weeks; and (5) sildenafil treated PBOO for 6 weeks. We assessed erectile function by measuring intracavernous pressures (ICP), mean arterial pressure (MAP) and total ICP after cavernous nerve stimulation. Corpus cavernous smooth muscle (CCSM) strips were isolated and evaluated for relaxation responses using organ-bath preparation. Neuronal nitric oxide synthase (nNOS) expression was determined immunohistochemically.

RESULTS

Experimental PBOO at 3 and 6 weeks showed decreased erectile response based on ICP/MAP ratio, total ICP and decreased expression of nNOS, which returned to normal after prolonged daily treatment with sildenafil. CCSM strips from PBOO rats displayed reduced relaxation responses to both electrical field stimulation (EFS) and acetylcholine (ACh) as well as nNOS enzyme intensity when compared to untreated PBOO group, which was reversed by treatment with sildenafil for 6 weeks.

CONCLUSIONS

Daily sildenafil treatment prevents development of ED in PBOO rats in a time dependent manner. Further studies are needed to explore the effectiveness of sildenafil in patients with BPH/LUTS in association with ED.

Current Diagnosis and Management of Erectile Dysfunction

Erectile dysfunction (ED) affects a growing number of men in the USA and abroad, with significant impacts on sexual function and overall quality of life. The risk factors for ED are numerous and include a strong link to cardiovascular disease, such that men with ED should be screened for cardiovascular disease. The evaluation of men presenting with ED includes a comprehensive history and physical exam to aid in the identification of comorbidities as well as laboratory testing to evaluate hormone and lipid levels and sugar metabolism. Adjunct studies are also available, though their utility is often limited to specific subtypes of ED. Once the etiology of ED is established, treatment can be initiated using appropriate medical therapies, including phosphodiesterase type 5 (PDE5) inhibitors, and transurethral or intracavernosal therapies, with surgical intervention via revascularization or penile prosthesis placement in men demonstrating a lack of response to medical therapy. In all cases of ED, a psychogenic component is present and referral for psychological intervention with or without medical therapy should be considered.

Pathogenic mechanisms linking benign prostatic hyperplasia, lower urinary tract symptoms and erectile dysfunction

INTRODUCTION

Erectile dysfunction (ED) and lower urinary tract symptoms (LUTS) caused by benign prostatic hyperplasia (BPH) are clinical entities very prevalent in men aged over 50 years. There is evidence that both may have a common pathophysiology.

OBJECTIVE

The objective of this study was to conduct a literature review aiming to show theories and hypotheses that justify a single pathophysiology for ED and LUTS/BPH.

METHODS

A search in Medline using the keywords of the Medical Subject Headings (MESH) 'erectile dysfunction' and 'lower urinary tract symptoms' in all fields of the database up to 15 December 2012. This search found 198 relevant articles that were analyzed.

RESULTS

The data and articles were divided according to the type of evidence found. There are strong epidemiological data showing that LUTS/BPH is a risk factor for developing ED. Several experimental models demonstrated partial obstruction of the bladder in animals causes voiding disorders as well as a negative impact on erectile function of the operated animals. The increased adrenergic tonus in animals leads to prostate growth and urodynamic conditions similar to those found in men with LUTS and ED. Arteriosclerosis may lead to loss of vesical complacency, urinary tract obstruction and fibrosis of the cavernous bodies. The use of phosphodiesterase type 5 inhibitors (PDE-5i) and/or alpha-adrenergic blockers to treat ED and LUTS/BPH reinforces the hypothesis that, at least in some patients, both clinical pictures may have the same pathophysiology.

The promise of inhibition of smooth muscle tone as a treatment for erectile dysfunction: where are we now?

Ten years ago, the inhibition of Rho kinase by intracavernosal injection of Y-27632 was found to induce an erectile response. This effect did not require activation of nitric oxide-mediated signaling, introducing a novel target pathway for the treatment of erectile dysfunction (ED), with potential added benefit in cases where nitric oxide bioavailability is attenuated (and thus phosphodiesterase type 5 (PDE5) inhibitors are less efficacious). Rho-kinase antagonists are currently being developed and tested for a wide range of potential uses. The inhibition of this calcium-sensitizing pathway results in blood vessel relaxation. It is also possible that blockade of additional smooth muscle contractile signaling mechanisms may have the same effect. In this review, we conducted an extensive search of pertinent literature using PUBMED. We have outlined the various pathways involved in the maintenance of penile smooth muscle tone and discussed the current potential benefit for the pharmacological inhibition of these targets for the treatment of ED.

Current benign prostatic hyperplasia treatment: impact on sexual function and management of related sexual adverse events

Benign prostatic hyperplasia (BPH) is a common disease in older men that can lead to lower urinary tract symptoms (LUTS). Male sexual dysfunction is also an age-related condition. Epidemiological studies have confirmed an association between BPH/LUTS and sexual dysfunction in ageing men that is independent of the effects of age, other co-morbidities and lifestyle factors. Proposed pathophysiological mechanisms for BPH/LUTS-associated sexual dysfunction include the nitric oxide/cyclic guanosine monophosphate (NO/cGMP) pathway, rho-kinase and endothelin-1 activity, autonomic nervous system overactivity and the metabolic syndrome, and pelvic organ atherosclerosis. Both BPH/LUTS and sexual dysfunction can have a substantial negative impact on a man's quality of life. However, urologists and primary care physicians appear to under-recognise sexual dysfunction in men with BPH/LUTS. Current guidelines recommend alpha-blockers and 5-alpha reductase inhibitors, either alone or in combination, among appropriate medical treatment options for BPH/LUTS. Randomised, controlled trials demonstrate that these therapies can be associated with sexual adverse effects (AEs) such as loss of libido, erectile dysfunction and ejaculatory disorders. Sexual dysfunction should be fully evaluated in men requiring treatment for BPH/LUTS using validated questionnaires. Management of sexual dysfunction in men treated for BPH/LUTS should involve assessment of co-morbidities and concomitant medications, consideration of lifestyle interventions such as weight loss and increased physical activity to improve risk factors and, if necessary, introduction of pharmacotherapies. In addition, physicians should provide patients with proper counselling on the possible sexual AEs of medical therapies for BPH/LUTS and their impact on sexual satisfaction, while being aware of the possibility that counselling in itself is likely to influence reported rates of sexual dysfunction.

Animal model for the study of the relationship between lower urinary tract symptoms/bladder outlet obstruction and erectile dysfunction

OBJECTIVES

Lower urinary tract symptoms (LUTS) are frequently associated with erectile dysfunction (ED) in aged men, and both significantly influence quality of life. However, the mechanism linking LUTS to ED has not been clarified completely. The purpose of the present study was to establish an animal model of ED following LUTS/bladder outlet obstruction (BOO) and investigate the expression of molecules related to the cause of this type of ED.

METHODS

Male Sprague-Dawley rats with partial BOO were used as an experimental model of LUTS. Sham-operated animals served as controls. Voiding and erectile function were evaluated 4, 8, and 16 weeks after obstruction or sham operation. The mRNA expression of penile tissue genes related to penile corporal smooth muscle relaxation was examined by quantitative real-time reverse transcription-polymerase chain reaction.

RESULTS

Voiding and bladder function of BOO rats were significantly worse than in sham-operated rats 4, 8, and 16 weeks after obstruction. The erectile function of BOO rats was significantly decreased compared with that of the sham-operated controls (P < 0.01) 16 weeks after obstruction, although it was similar to that of sham-operated animals at 4 and 8 weeks after obstruction. The expression of endothelial nitric oxide synthase (eNOS) mRNA was significantly decreased 16 weeks after obstruction compared with that in sham-operated rats (P < 0.01).

CONCLUSION

An animal model for investigations into the association between LUTS and ED is described herein. Endothelial dysfunction induced by impaired eNOS function is likely to be involved in ED following LUTS/BOO.

Update on corpus cavernosum smooth muscle contractile pathways in erectile function: a role for testosterone?

INTRODUCTION

Normal erectile function (EF) involves a coordinated relaxation of the arteries that supply the penis and the corpus cavernosum smooth muscle (CCSM), resulting in expansion of the sinusoids and increased intracavernous pressure. But the CCSM spends the majority of its time in the contracted state which is mediated by norepinephrine released from nerve endings and other vasoconstrictors like endothelins released from the endothelium. These agents cause smooth muscle myosin (SMM) phosphorylation by elevating intracellular calcium. When calcium returns to basal levels, the calcium sensitivity increases and prevents myosin dephosphorylation, which involves the RhoA/Rho-kinase (ROK) mechanism, thus maintaining force. Although mounting evidences demonstrate that androgens have a major influence on EF that is not just centrally mediated, this notion remains quite controversial.

AIM

To summarize the current knowledge on CCSM contractile pathways, the role they play in modulating EF, and the influence of androgens.

METHODS

The article reviews the literature and contains some previously unpublished data on CCSM contraction signaling including the role that androgens are known to play in modulating these pathways.

MAIN OUTCOME MEASURES

Data from peer-reviewed publications and previously unpublished observations.

RESULTS

In addition to downregulation of many pro-erectile molecular mechanisms, decreased testosterone (T) levels upregulate CCSM contractility, including hyperresponsiveness to α-adrenergic agonists, increased SMM phosphorylation, alteration of SMM isoform composition, activation of RhoA/ROK signaling and modulation of sphingosine-1-phosphate regulation of CCSM tone.

CONCLUSIONS

Decreased T levels upregulate CCSM contractile signaling. Meanwhile, it downregulates CCSM relaxation pathways synergizing to produce erectile dysfunction (ED). Although some urologists and researchers are still skeptical of the influence of androgens on penile erection, understanding these molecular control mechanisms as well as the influence that androgens have on these pathways should provide new evidence supporting the roles of androgens in EF and enhance the discovery of novel targets for drug development to treat ED.

Up-regulation of the RhoA/Rho-kinase signaling pathway in corpus cavernosum from endothelial nitric-oxide synthase (NOS), but not neuronal NOS, null mice

We tested the hypothesis that the basal release of nitric oxide (NO) from endothelial cells modulates contractile activity in the corpus cavernosum (CC) via inhibition of the RhoA/Rho-kinase signaling pathway. Cavernosal strips from wild-type (WT), endothelial nitric-oxide synthase knockout [eNOS(-/-)], and neuronal nitric-oxide synthase knockout [nNOS(-/-)] mice were mounted in myographs, and isometric force was recorded. mRNA and protein expression of key molecules in the RhoA/Rho-kinase pathway were analyzed by real-time polymerase chain reaction and Western blot, respectively. The cGMP levels were determined. The Rho-kinase inhibitors (R)-(+)-trans-N-(4-pyridyl)-4-(1-aminoethyl)-cyclohexanecarboxamide (Y-27632) and (S)-(+)-2-methyl-1-[(4-methyl-5-isoquinolinyl)sulfonyl] homopiperazine (H-1152) reduced cavernosal contractions evoked by phenylephrine or electrical field stimulation (EFS) in a concentration-dependent manner, although this inhibition was less effective in tissues from eNOS(-/-) mice. Y-27632 enhanced relaxations induced by sodium nitroprusside, EFS, and NO (administered as acidified NaNO2) without affecting the cGMP content of the cavernosal strips. This enhancement was less prominent in CC from eNOS(-/-). The protein expression of RhoA, Rho-guanine dissociation inhibitor, and Rho-kinase beta did not differ among the strains. However, in eNOS(-/-) CC, the protein expression of Rho-kinase alpha and both mRNA and protein expression of p115-Rho-associated guanine exchange factor (RhoGEF), PDZ-RhoGEF, and leukemia-associated RhoGEF were up-regulated. Phosphorylation of MYPT1 at Thr696 was higher in tissues from eNOS(-/-) mice. A high concentration of Y-27632 significantly enhanced NO release in CC stimulated by EFS. These results suggest a basal release of NO from endothelial cells, which inhibits contractions mediated by the RhoA/Rho-kinase pathway and modulates the expression of proteins related to this pathway in mouse CC. It indicates that endothelial integrity is essential to the maintenance of erectile function.

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.

The effect of chronic partial bladder outlet obstruction on corpus cavernosum smooth muscle and Rho-kinase in rabbits

AIM

The goal of this study was to investigate the effect of different severities in bladder dysfunction on corpus cavernosum physiology, morphology and expression of Rho-kinase in rabbits.

METHODS

Male New Zealand rabbits were divided into control, 2 and 8 weeks of partial bladder outlet obstruction (PBOO) groups. Isolated cavernosal strips from all groups were precontracted with phenylephrine and the relaxant responses to electrical field stimulation (EFS), ATP, acetylcholine, and sodium nitroprusside (SNP) were determined. Histological and molecular studies were performed.

RESULTS

Corpus cavernosum smooth muscle (CCSM) from 8 weeks obstruction rabbits showed significant decreases in the contractile response to phenylephrine and further decreased relaxation responses to EFS in comparison to 2 weeks group. Relaxation induced by ATP, acetylcholine, and SNP were all significantly diminished at both 2 and 8 weeks obstruction equally. The ratio of smooth muscle to collagen decreased at 2 weeks and further dropped at 8 weeks obstruction. Expression of both isoforms of Rho-kinase were increased in both obstruction groups at 2 weeks obstruction and decreased significantly (from the 2 week obstructed values) at 8 weeks while remaining above control values.

CONCLUSION

The present study indicated that severe bladder dysfunction secondary to chronic PBOO induced significant physiological dysfunctions of CCSM as well as morphological changes. Activities of both ROK isoenzymes showed increases at 2- and 8-week obstructions. Increase in Rho-kinase expression/activity would be expected to make the CCSM more difficult to relax and also contribute to reduction of EFS-induced relaxation of CCSM after chronic PBOO.

Comparative efficacy assessment of tamsulosin vs. tamsulosin plus tadalafil in the treatment of LUTS/BPH. Pilot study

INTRODUCTION

The high incidence of erectile dysfunction (ED) and lower urinary tract symptoms (LUTS) in aging men and the same pathophysiology make probable to treat both disorders with the same treatment. Numerous authors evaluated the actions of PDE5i in improving the LUTS/(benign prostate hyperplasia) BPH.

AIM

To assess the efficacy and safety of tamsulosin 0.4 mg/day vs. tamsulosin 0.4 mg/day plus tadalafil 20 mg/day in patients with LUTS in a crossover design study.

MAIN OUTCOMES MEASURES

International Prostate Symptoms Score (IPSS), IPSS Quality of Life (IPSS-QOL), maximum flow rate (Qmax), post-void residual volume (PVR), International Index of Erectile Function-Erectile Function Domain (IIEF-EF), Global Assessment Quality (GAQ). For the statistical analysis, a Tukey-Kramer multicomparison test was used.

METHODS

A randomized, double-blind, crossover study was conducted from September 2007 to February 2008 in one center. Thirty men, older than 50 years old, with a history of LUTS/BPH of at least 6 months, were randomized into two groups to receive tamsulosin 0.4 mg/day vs. tamsulosin 0.4 mg/day plus tadalafil 20 mg/day for 45 days, and then switched to the other treatment mode for other 45 days.

RESULTS

Twenty-seven patients completed the study. Improvements of IPSS score and IPSS-QOL were significant with both treatments but greater with the drug combination. Both regimens similarly improved the Qmax and decreased the PVR volume from baseline (P < 0.001) with no significant differences between tamsulosin alone vs. tamsulosin and tadalafil (P > 0.05). The IIEF improved with tamsulosin plus tadalafil (P < 0.001) but not with tamsulosin alone (P > 0.05). The GAQ showed that all patients preferred the combination scheme. Both treatments were well tolerated. CONCLUSION; Tamsulosin 0.4 mg/day plus tadalafil 20 mg/day was more effective than tamsulosin 0.4 mg/day alone to improve LUTS and erectile dysfunction and was also well tolerated. Large-scale, randomized, placebo-controlled studies are needed to further assess the long-term safety and effectiveness of these agents in treating LUTS/BPH with or without ED.

Contractile changes of the clitoral cavernous smooth muscle in female rabbits with experimentally induced overactive bladder

INTRODUCTION

Recently, growing clinical evidence has suggested that sexual dysfunction is more prevalent in women with overactive bladder (OAB). Aims. However, there has been no basic research to clarify the relationship between OAB and female sexual dysfunction. Therefore, we investigated this issue using a rabbit model of OAB.

METHODS

Twenty-seven New Zealand white female rabbits were randomly divided into the OAB and control groups.

MAIN OUTCOME MEASURES

The contractile responses of clitoral cavernous strips to K(+), phenylephrine (PE), Bay K 8644, and endothelin (ET)-1, and the relaxation responses of acetylcholine (ACh), sodium nitroprusside (SNP), and Y-27632 to PE-induced contraction by measuring isometric tension. Results. The contractile responses to K(+), PE, Bay K 8644, and ET-1 were significantly more increased in the OAB group in a dose-dependant manner than in the control group (P < 0.05), and the responses to ET-1 were more prominent than those to the remaining substances (P < 0.01). The increased contractile responses to ET-1 were blocked by BQ123 (ET(A) receptor antagonist) but not by BQ788 (ET(B) receptor antagonist). Clitoral cavernosal strips from the OAB group were more difficult to relax than those from the control group in terms of ACh- and SNP-induced relaxation (P < 0.05). The Y-27632-induced relaxant responses to PE- and ET-1-induced contraction were less prominent in the OAB group than in the control group. CONCLUSIONS; The results of this study provide evidence that female OAB may deteriorate clitoral engorgement, which is associated with a greater force generation by increased calcium sensitization and subsequently decreased of relaxation. The activation of ET and Rho-kinase system may be crucial to negatively effect the clitoral smooth muscle relaxation in experimentally induced OAB animal model. But whether these vasomotor effects are revived in human clitoris is still debatable.

Identifying patients with benign prostatic hyperplasia through a diagnosis of, or treatment for, erectile dysfunction

OBJECTIVE

Erectile dysfunction (ED) and lower urinary tract symptoms (LUTS) associated with benign prostate hyperplasia (BPH) are highly correlated. This study examined rates of screening, diagnosis, and treatment of BPH/LUTS among men seeking care for ED.

RESEARCH DESIGN AND METHODS

This was a retrospective US claims data analysis (1999-2004) evaluating men > or = 40 years old with a new diagnosis of or prescription medication for ED. Multivariate analyses were used to examine times to screening, diagnosis, and treatment.

RESULTS

81 659 men with ED were identified (mean age 57 years). The baseline prevalence of recorded BPH was 1.5%. During the follow-up period (mean 2.2 years), 7.6% had documented BPH. Time to screening was shorter among patients seeing urologists (121.1 days) compared with those seeing primary-care physicians (282.2 days). Controlling for demographic and clinical characteristics, patients who saw a urologist were more likely to be screened (OR: 2.4, p < 0.0001), diagnosed with BPH (OR: 1.8, p < 0.0001), and treated (OR: 1.3, p < 0.0001), relative to patients seeing other providers. Men aged 75 and over were 43% less likely to be screened (p < 0.0001), but 5.4 times more likely to be diagnosed with BPH (p < 0.0001) and 5.3 times more likely to be treated (p < 0.0001) compared with men aged 40-49.

CONCLUSIONS

Screening for BPH appears less likely for men with ED who do not see a urologist. When screening does occur, it takes much longer with non-specialty providers. Patient age and provider specialty are key factors associated with screening, diagnosis, and treatment of BPH among men with ED.

Rho GTPase/Rho kinase inhibition as a novel target for the treatment of glaucoma

Rho kinase (ROCK1 and ROCK2) is a serine/threonine kinase that serves as an important downstream effector of Rho GTPase, and plays a critical role in regulating the contractile tone of smooth muscle tissues in a calcium-independent manner. Several lines of experimental evidence indicate that modulating ROCK activity within the aqueous humor outflow pathway using selective inhibitors could achieve very significant benefits for the treatment of increased intraocular pressure in patients with glaucoma. The rationale for such an approach stems from experimental data suggesting that both ROCK and Rho GTPase inhibitors can increase aqueous humor drainage through the trabecular meshwork, leading to a decrease in intraocular pressure. In addition to their ocular hypotensive properties, inhibitors of both ROCK and Rho GTPase have been shown to enhance ocular blood flow, retinal ganglion cell survival and axon regeneration. These properties of the ROCK and Rho GTPase inhibitors indicate that targeting the Rho GTPase/ROCK pathway with selective inhibitors represents a novel therapeutic approach aimed at lowering increased intraocular pressure in glaucoma patients.

Tadalafil for the treatment of lower urinary tract symptoms in men with benign prostatic hyperplasia

This article reviews the pharmacological properties of tadalafil and the current evidence supporting its use for treating symptomatic benign prostatic hyperplasia (BPH). The rationale for using tadalafil for BPH stems from the following three observations: first, the prevalence of lower urinary tract symptoms (LUTS), BPH and erectile dysfunction (ED) increases with age; second, phosphodiesterase-5 (PDE5) inhibition mediates smooth muscle relaxation in the lower urinary tract; and third, early clinical evidence demonstrates that PDE5 inhibitors such as tadalafil are successful in treating LUTS and ED. A shared pathophysiology makes PDE5 a promising target to treat both LUTS and ED. A recent randomised, controlled Phase II trial of tadalafil versus placebo for the treatment of symptomatic BPH revealed that tadalafil dosed once daily was well tolerated and demonstrated statistically significant and clinically meaningful efficacy in the treatment of LUTS secondary to BPH and improved erectile function in men with both LUTS and ED. The ability to treat both BPH and ED with one medication is noteworthy given the significant negative impact in quality-of-life measures these disorders have in ageing men. Careful patient selection and further trials are warranted.

Effect of Doxazosin With and Without Rho-Kinase Inhibitor on Human Corpus Cavernosum Smooth Muscle in the Presence of Bladder Outlet Obstruction

PURPOSE

We investigated the relationship of adrenergic responses in corpus cavernosum tissues in the presence of BOO using the alpha1-adrenergic receptor antagonist doxazosin (Pfizer, New York, New York) and the rho-kinase inhibitor Y-27632 (Calbiochem, San Diego, California).

MATERIALS AND METHODS

CCSM tissue was obtained from patients who underwent penile prosthesis implantation. Patients were divided into 2 groups according to the presence of BOO. The submaximal (EC80) concentration of phenylephrine (Sigma Chemical Co., St. Louis, Missouri) was calculated by evaluating adrenergic activity responses with cumulatively applied phenylephrine. After achieving a stable contraction plateau test compounds were put in an organ bath. The relaxant potencies of doxazosin and Y-27632 were expressed as the percent of inhibition of the contraction plateau induced EC80 concentration of phenylephrine. Relaxation responses in the 2 groups were compared.

RESULTS

At the highest dose of increasing concentrations phenylephrine generated 70% more contraction response in the BOO positive group than in the BOO negative group. Doxazosin and Y-27632 caused concentration dependent relaxation in CCSM precontracted by phenylephrine. With doxazosin significantly higher relaxation responses were attained in the BOO positive group in terms of log IC50 and the maximal relaxation response (p = 0.0353 and 0.0003, respectively). Maximum relaxation responses following Y-27632 administration were significantly higher in the BOO positive group.

CONCLUSIONS

The contractility of human corpus cavernosum is increased in the presence of BOO. Doxazosin and Y-27632 generate effective CCSM relaxation in the presence of BOO. Doxazosin and Y-27632 may be the alternatives for the treatment of erectile dysfunction associated with BPH.

Lower urinary tract symptoms and erectile dysfunction are highly prevalent in ageing men

OBJECTIVE

To evaluate a possible correlation between the International Prostate Symptom Score (IPSS) and the Sexual Health Inventory for Men (SHIM) in an unselected population of men presenting to a clinic, as lower urinary tract symptoms (LUTS) and erectile dysfunction (ED) are highly prevalent in ageing men, and recent largely community-based epidemiological studies reported a close association between ED and LUTS.

PATIENTS AND METHODS

This was a cross-sectional study in an unselected consecutive sample of 118 men aged >40 years attending a urology clinic; the reason for consulting was not ascertained. While in the waiting room the men were asked to participate in the study and on agreement were given the IPSS and the SHIM to complete.

RESULTS

The mean (range) age of the participants was 61.7 (45-82) years. Overall, 19 (16%) and 47 (40%) of the men reported having moderate or severe LUTS, respectively. Erectile problems were also common, the prevalence of moderate ED was 11% and complete ED 29%. The Pearson correlation coefficient between the IPSS and the SHIM was - 0.32 (P < 0.001).

CONCLUSION

There was a close correlation between the IPSS and SHIM in this unselected population of men, adding evidence favouring a close association between LUTS and ED.

Lower urinary tract symptoms and sexual dysfunction: epidemiology and pathophysiology

There is ample evidence from many epidemiological studies that lower urinary tract symptoms (LUTS) and sexual dysfunction are strongly linked, independently of age and comorbidities such as hypertension, diabetes, dyslipidaemia and coronary heart disease. However, a causal link between both conditions is not yet established. Four pathophysiological mechanisms currently support the relationship between LUTS and erectile dysfunction (ED): (i) The nitric oxide synthase (NOS)/NO theory; there is a reduction in NOS-containing nerves in the prostate and bladder/urethra in patients with bladder outlet obstruction (BOO), and that lack of NO or loss of protein kinase G causes ED; (ii) The autonomic hyperactivity and metabolic syndrome hypothesis: benign prostatic hyperplasia (BPH) may be part of the metabolic syndrome, which includes cardiovascular diseases (e.g. hypertension, ischaemic heart disease) and diabetes mellitus, known risk factors for ED. Hypertension, obesity, and hyperinsulinaemia have all been claimed to be associated with an increased sympathetic activity. Increased sympathetic activity is involved in LUTS/BPH and may have a role in ED/sexual dysfunction, with noradrenaline and alpha1-adrenoceptors representing a common link; (iii) the Rho-kinase activation/endothelin pathway; there can be increased Rho-kinase activity, and consequently calcium sensitivity of the contractile machinery, in prostate smooth muscle in BPH, the detrusor in BOO, corpora cavernosa in ED, and in the resistance vessels in hypertension. The actions of several factors beside noradrenaline (e.g. endothelin-1, angiotensin II), possibly involved in the increased smooth muscle activity found in both LUTS/BPH and sexual dysfunction, are dependent on Rho-kinase activity. Thus increased Rho-kinase activity might represent a common link between LUTS and sexual dysfunction; (iv) Pelvic atherosclerosis; animal models mimicking pelvic ischaemia and hypercholesterolaemia show similar smooth muscle alterations of the detrusor and corpora. Pelvic ischaemia may induce the biological modifications described above and may thus represent as well a common link between LUTS and sexual dysfunction. Studies treating one condition (e.g. ED) and measuring the impact on the other (e.g. LUTS) should further contribute to support this common link.