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

Evaluation of the effect of sildenafil and/or doxazosin on Benign prostatic hyperplasia-related lower urinary tract symptoms and erectile dysfunction

PURPOSE

To verify the association between lower urinary tract symptoms (LUTS) and erectile dysfunction (ED) and evaluate the influence of sildenafil and doxazosin either as single agents or combined on both symptoms.

MATERIAL AND METHODS

A prospective randomized study including 150 patients presented with LUTS caused by BPH in association with clinically diagnosed ED, with age equal or more than 45 years from April 2010 to April 20011. They were categorized into three comparative groups each one containing 50 patients. These groups were comparable regarding pretreatment international prostate symptoms score (IPSS) and international index of erectile function (IIEF). The patients of the first group were given sildenafil 50 mg as monotherapy, those of the second group were given doxazosin 2 mg and those of the third group were given combination of both drugs for 4 months for each group. The main post-treatment parameters for assessment and comparison include assessment of patient's symptoms by repeated IPS Sand IIEF, uroflowmetry and assessment of PVR. The statistics was done by use of the Qui--square test.

RESULTS

Pre-treatment parameters were assessed and compared between the three groups. After 4 months of treatment, the comparative parameters were applied to all groups and the differences were measured post-treatment regarding IPSS, erectile function score, uroflowmetry, and post-void residual (PVR) urine. Sildenafil alone caused mild improvement in IPSS, more improvement in IIEF score, and little effect on flow rate and PVR urine. Doxazosin alone caused more improvement in IPSS, flow rate and PVR urine and less improvement in IIEF score. A combination of both sildenafil and doxazosin caused more improvement in all of the comparative parameters than when each drug was given alone.

CONCLUSIONS

There is a strong relationship between LUTS and ED. Doxazosin or sidenafil as a single drug could be used in treating mild or mild to moderate symptoms but more severe symptoms may usually need a combination of both drugs.

Rho kinase (ROK)-related proteins in human cavernous arteries: an immunohistochemical and functional approach

INTRODUCTION

Rho kinases (ROKs) cause calcium-independent modulation of smooth muscle contraction. A significant role for the RhoA/ROK pathway in mediating the contraction of the penile erectile tissue has been suggested. Moreover, it has been postulated that ROK activity might represent a key factor in the pathophysiology of erectile dysfunction. Up until today, little is known on the significance of ROK and related proteins in the control of blood flow in the corpus cavernosum.

AIM

To investigate by means of immunohistochemistry and organ bath studies the significance of the Rho pathway in human cavernous arteries.

MAIN OUTCOME MEASURES

The expression of ROK1, ROK2, RhoA, and RhoGDI in human cavernous arteries was investigated by means of immunohistochemistry; myographic studies were conducted in order to characterize the effects of the ROK inhibitor Y27632 on isolated cavernous arteries.

METHODS

Specimens of human cavernous arteries were processed for immunohistochemistry for ROK1, ROK2, RhoA, and RhoGDI. Circular penile vascular segments were mounted in a tissue bath and the effects of increasing concentrations of the ROK inhibitor Y27632 on the tension induced by norepinephrine (NE, 1 µM) were investigated.

RESULTS

Alpha-actin immunoreactive cavernous arterioles also presented abundant staining specific for ROK1, ROK2, RhoA, and RhoGDI in the smooth musculature of the vascular wall. Cumulative addition of Y27632 dose-dependently reversed the tension induced by NE of isolated arterial segments. Y27632 produced relaxant responses with a reversion of tension of 34.3 ± 11.8% at a concentration of 1 µM.

CONCLUSION

The findings are in support for a role of the Rho/ROK-mediated signaling in the regulation of muscle tone of human cavernous arteries.

Future sexual medicine physiological treatment targets

INTRODUCTION

Sexual function in men and women incorporates physiologic processes and regulation of the central and peripheral nervous systems, the vascular system, and the endocrine system. There is need for state-of-the-art information as there is an evolving research understanding of the underlying molecular biological factors and mechanisms governing sexual physiologic functions.

AIM

To develop an evidence-based, state-of-the-art consensus report on the current knowledge of the major cellular and molecular targets of biologic systems responsible for sexual physiologic function.

METHODS

State-of-the-art knowledge representing the opinions of seven experts from four countries was developed in a consensus process over a 2-year period.

MAIN OUTCOME MEASURES

Expert opinion was based on the grading of evidence-based medical literature, widespread internal committee discussion, public presentation, and debate.

RESULTS

Scientific investigation in this field is needed to increase knowledge and foster development of the future line of treatments for all forms of biological-based sexual dysfunction. This article addresses the current knowledge of the major cellular and molecular targets of biological systems responsible for sexual physiologic function. Future treatment targets include growth factor therapy, gene therapy, stem and cell-based therapies, and regenerative medicine.

CONCLUSIONS

Scientific discovery is critically important for developing new and increasingly effective treatments in sexual medicine. Broad physiologic directions should be vigorously explored and considered for future management of sexual disorders.

The effect of alpha-blocker therapy on erectile functions in patients with lower urinary tract symptoms due to benign prostate hyperplasia

In this study we aimed to evaluate the impact of doxazosin treatment on erectile functions in patients with lower urinary tract symptoms (LUTS) and having erectile dysfunction (ED) at baseline. Fifty-three patients with LUTS (IPSS score > 7) whose maximum flow rate (Q(max)) < 15 mL s(-1) and PSA < 4 ng dL(-1) were enrolled in the study. Patients received doxazosin 4 mg once daily for 6 weeks. Subjective efficacy was assessed by IPSS, IPSS-Quality of Life (IPSS-QoL) for LUTS and efficacy was assessed by International Index of Erectile Function (IIEF) for erectile functions at baseline and sixth weeks. The objective efficacy was assessed by Q(max). The patients were classified according to their self reported erectile status: group I had ED and group II did not have ED. At the endpoint, doxazosin significantly improved the total IPSS score (-7.7 +/- 6.1, P = 0.006), IPSS-QoL score (-1.5 +/- 1.5, P = 0.024) and Q(max) (3.2 +/- 4.6 mL s(-1), P = 0.002) over baseline. Mean decrease in IPSS and IPSS-QoL scores after the treatment period were 6.9 +/- 6.4 (P < 0.001) and 0.95 +/- 1.80 (P < 0.05) in group I, whereas 8.2 +/- 5.8 (P < 0.001) and 1.9 +/- 1.1 in group II (P < 0.001), respectively. Mean changes of Q(max) values were 2.3 +/- 3.3 mL s(-1) in group I (P < 0.05) and 3.7 +/- 5.3 mL s(-1) in group II (P < 0.001). The improvement of IIEF-EF scores after the treatment period was only significant for group I. The efficacy of alpha-blocker therapy for LUTS was better by means of symptomatic relief for patients who did not have ED when compared with patients who had ED at baseline. However, slight improvement in erectile functions with alpha-blocker therapy was only seen in LUTS patients with ED.

Alpha-blocker use is associated with decreased risk of sexual dysfunction

OBJECTIVES

To examine the association between alpha-blocker use and sexual dysfunction among men participating in a population-based cohort of men residing in Olmsted County, MN. Lower urinary tract symptoms (LUTS) in men have previously been associated with sexual dysfunction. The use of alpha-adrenergic receptor blocking agents results in an improvement in LUTS for many men. If sexual dysfunction and LUTS share a common etiology, alpha-blocker use might also be associated with a decreased risk of sexual dysfunction.

METHODS

White men, aged 40-79 years, were randomly selected in 1990 and assessed for alpha-blocker use and LUTS severity. Sexual function was assessed using the Brief Male Sexual Function Inventory. Men who used alpha-blockers before any sexual dysfunction were considered "exposed." Hazard ratios and 95% confidence intervals were estimated separately for each sexual function domain using Cox proportional hazard models.

RESULTS

Of the 1724 men with a regular sexual partner included in the present study (mean age 57.74 years), 263 (15.3%) reported alpha-blocker use. alpha-Blocker use was associated with a decreased risk of sexual dysfunction across all domains for men > or =50 years old (age-adjusted hazard ratio 0.53-0.69). A decreased risk of erectile dysfunction and low libido remained significant only among those using alpha-blockers who also experienced an improvement in LUTS (P = .01).

CONCLUSIONS

The use of alpha-blockers for LUTS was associated with a decreased risk of sexual dysfunction. Improvement in sexual function correlated with the improvement in LUTS more strongly among those using alpha-blockers.

Association between severity of lower urinary tract symptoms, erectile dysfunction and metabolic syndrome

INTRODUCTION

The purpose of this study was to investigate the association between severity of lower urinary tract symptoms (LUTS), erectile dysfunction (ED) and metabolic syndrome.

METHODS

Our study population included a consecutive series of 190 patients with LUTS (International Prostate Symptom Score-IPSS >7) with or without manifestations of the metabolic syndrome. The diagnoses of diabetes mellitus and hypertension were obtained from the patient's medical history. Data on blood pressure, waist measure, body height and weight were collected and body mass index were calculated. Patients were assessed based on the International Index of Erectile Function (IIEF) for ED and IPSS and IPSS-Quality of Life for LUTS. Blood samples were drawn from fasting patients to determine, fasting blood glucose (FBG), triglycerides, HDL-cholesterol and serum total testosterone levels.

RESULTS

In severe LUTS patient group, IIEF erectile function domain scores were significantly lower than moderate LUTS patient group (p < 0.05). Multiple logistic regression analysis confirmed that presence of ED was the most predictor of severe LUTS. The prevalence of metabolic syndrome was higher in patients with severe LUTS (26%vs. 46%, p = 0.009). The severe form of the LUTS was significantly correlated with waist circumference >102 cm (p < 0.05), blood pressure > or =130/85 mmHg (p < 0.05) and FBG >110 mg/dl (p < 0.01).

CONCLUSION

Obesity, high plasma level of FBG and hypertension constitute risk factors for the development of severe LUTS. Metabolic syndrome may play a key role in the pathogenesis in both ED and LUTS. Presence of ED is the most predictor of severe LUTS.

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.

Combination of alfuzosin and tadalafil exerts in vitro an additive relaxant effect on human corpus cavernosum

INTRODUCTION

Phosphodiesterase type 5 (PDE5) inhibitors, such as tadalafil, are a first-line treatment for erectile dysfunction (ED). Nevertheless, some patients do not respond to this treatment. Clinical data suggest that the addition of alpha1-adrenoceptor blocker, such as alfuzosin, commonly prescribed for lower urinary tract symptoms suggestive of benign prostatic hyperplasia, may be of benefit. Aim. Evaluation of the effect of alfuzosin, tadalafil or the combination of both on human corpus cavernosum.

METHODS

Human cavernosal tissues were obtained from 10 patients undergoing penile surgery. Strips contractility was studied in organ baths. Concentration-response curves to tadalafil were generated on norepinephrine (NE, 1-10 microM)-precontracted strips in the presence of alfuzosin or vehicle. Frequency-response curves (FRC) to electrical field stimulation (EFS, 0-64 Hz, 3 ms, 10 seconds, 300 mA) were generated in the presence of vehicle, alfuzosin, tadalafil, or both drugs combined. EFS (20 Hz, 1 ms, 10 seconds, 300 mM)-induced nitrergic relaxation on NE-precontracted strips was studied in the presence of vehicle, alfuzosin, tadalafil, or both drugs combined.

MAIN OUTCOME MEASURES

Functional measurement of cavernosal smooth muscle relaxation in the presence of tadalafil and alfuzosin.

RESULTS

The relaxation induced by tadalafil (10(-10) to 10(-5) M) on precontracted strips was enhanced by alfuzosin at both 10(-8) and 10(-7) M. The combination of alfuzosin (3.10(-8) M) and tadalafil (10(-7) M) was more efficient to inhibit FRC-induced contractions than each compound alone. The combination of tadalafil (10(-6) M) and alfuzosin (10(-8) M) increased the relaxation induced by EFS and its effect was greater than tadalafil alone. In addition, the combination of tadalafil (10(-6) M) and alfuzosin (10(-7) M) prolonged EFS-induced relaxation to a greater extent than each compound alone.

CONCLUSIONS

In vitro, the combination of alfuzosin and tadalafil is more efficient than each compound alone to relax adrenergic tone or to enhance nitrergic relaxation of the human corpus cavernosum. Such a combination deserves further investigation in placebo-controlled studies to evaluate its benefit in ED patients who are not sufficiently improved by PDE5 inhibitors.