MODULATION OF BLADDER ??1-ADRENERGIC RECEPTOR SUBTYPE EXPRESSION BY BLADDER OUTLET OBSTRUCTION:

Comparison of two alpha1-adrenoceptor antagonists, naftopidil and tamsulosin hydrochloride, in the treatment of lower urinary tract symptoms with benign prostatic hyperplasia: a randomized crossover study

OBJECTIVES

To compare the efficacy of two alpha(1)-adrenoceptor antagonists, alpha(1A)-adrenoceptor-selective tamsulosin hydrochloride and alpha(1D)-adrenoceptor-selective naftopidil, in the treatment of lower urinary tract symptoms (LUTS) with benign prostatic hyperplasia (BPH).

PATIENTS AND METHODS

Thirty-four patients (mean age 72.4 years, sd 4.3, range 66-79) with LUTS (International Prostate Symptom Score, IPSS >8) secondary to BPH were enrolled in a randomized crossover study. Seventeen patients were initially prescribed naftopidil 50 mg for 4 weeks, followed by tamsulosin 0.2 mg for 4 weeks (group A); another 17 were initially prescribed tamsulosin 0.2 mg, followed by naftopidil 50 mg (group B). Patients changed to the alternative treatment after a 1-week washout period. Efficacy criteria were improvement in LUTS (IPSS), quality of life (QoL), uroflowmetry, and pressure-flow study (PFS) values based on the treatment with each agent.

RESULTS

At baseline there were no significant differences between the groups in IPSS, QoL, uroflowmetry values or PFS values, except for the volume at maximum desire to void. After treatment with each agent, the IPSS and QoL were significantly improved and the reduction in bladder outlet obstruction confirmed by PFS. Naftopidil was significantly more effective than tamsulosin in relieving nocturia. The increases from baseline (before treatment) to the endpoint (after treatment with each agent) in the volume at first desire and maximum desire to void were significantly higher with naftopidil than with tamsulosin. Involuntary contractions disappeared in two patients with relief of nocturia with naftopidil, but not with tamsulosin. The decrease in other symptoms of the IPSS, QoL, increase in uroflowmetry values and changes in other PFS values were similar for both agents.

CONCLUSIONS

The two agents provided similar efficacy in the treatment of LUTS with BPH. However, naftopidil was better than tamsulosin for nocturia. The disappearance of involuntary contraction and the greater increase in first-desire volume with naftopidil may be associated with the relief of nocturia. The alpha(1D)-adrenoceptor antagonist is effective in alleviating both voiding and storage symptoms. The alpha(1D)-adrenoceptor antagonist may be more effective than the alpha(1A)-adrenoceptor antagonist in LUTS with BPH.

Effects of Selective Alpha-1-Adrenergic Receptor Blockers on Bladder Weight

INTRODUCTION

This study was undertaken to investigate the effects of two different alpha(1)-adrenergic blockers on bladder hypertrophy using ultrasound-estimated bladder weight (UEBW) and to assess the relation between changes in UEBW and other objective and subjective parameters of disease severity in patients with benign prostatic hyperplasia (BPH).

MATERIALS AND METHODS

41 men were enrolled in the study and they were subjected to either watchful waiting (group 1) or alpha(1)-adrenergic receptor blocker therapy (group 2 with alfuzosin; group 3 with tamsulosin). The patients were investigated by symptom evaluation using the International Prostate Symptom Score (IPSS) and quality of life score (QOL), uroflowmetry and UEBW. The parameters were assessed again 3 months after initiation of treatment and compared with the initial values.

RESULTS

While the mean UEBW increased in group 1 (42.2 +/- 10.3 to 52.5 +/- 12.2 g), it decreased in both the other groups that received alpha-blocker therapy (61.3 +/- 18.7 to 41.1 +/- 13.2 and 59.4 +/- 17.2 to 43.5 +/- 17.6 g, respectively). In groups 2 and 3, the mean UEBW, post-void residual urine, IPSS and QOL values decreased, and the mean maximum flow rate increased. All of the changes in group 2 and all except QOL in group 3 were statistically significant (p < 0.05). The changes correlated well with each other with regard to treatment success. The highest decreases in UEBW were encountered in patients with heavier bladders.

CONCLUSIONS

UEBW decreases with alpha(1)-adrenergic receptor blockers. When used together with the other objective and subjective parameters, UEBW is a promising quantitative parameter as a follow-up tool and can be useful in monitoring the therapeutic effects of alpha(1)-adrenergic receptor blockers.

Comparison of tamsulosin and naftopidil for efficacy and safety in the treatment of benign prostatic hyperplasia: a randomized controlled trial

OBJECTIVES

To compare the efficacy and safety of two alpha1a/alpha1d adrenoceptor (AR) antagonists with different affinity for the alpha1AR subtypes, tamsulosin and naftopidil, in the treatment of benign prostatic hyperplasia (BPH).

PATIENTS AND METHODS

Patients with BPH were randomized to receive either tamsulosin or naftopidil. The primary efficacy variables were the changes in the total International Prostate Symptom Score (IPSS), maximum flow rate on free uroflowmetry, and residual urine volume. The secondary efficacy variables were average flow rate, changes in the IPSS storage score, IPSS voiding score, and quality-of-life (QoL) Index score, from baseline to endpoint (12 weeks). Data on all randomized patients were included in the safety analyses for adverse effects and changes in blood pressure.

RESULTS

Of the 185 patients enrolled data for 144 who were eligible for inclusion in the efficacy analysis were analysed (75 from the tamsulosin and 69 from the naftopidil group). There was no significant difference in any variable at baseline between the groups. There were statistically significant improvements for all primary and secondary variables in both groups, except for residual urine in the tamsulosin group. However, there was no significant intergroup difference in the improvement of any efficacy variable between the groups. The adverse effects were comparable, with no significant differences in systolic and diastolic blood pressure after treatment in both groups.

CONCLUSIONS

This study suggests that naftopidil is as effective and safe as tamsulosin. Both drugs were effective in improving storage and voiding symptoms. However, there was no difference in clinical efficacy or adverse effects between the alpha1 AR antagonists with different affinity to alpha1 subtypes, alpha1a and alpha1d.

Do BPH Patients Have Neurogenic Detrusor Dysfunction? A Uro-Neurological Assessment

INTRODUCTION

Most men with benign prostatic hyperplasia (BPH) are middle- aged and elderly. Neurogenic detrusor dysfunction (NDD) may also occur in these populations. We made an uro-neurological assessment in such patients in order to investigate the possibility of a concurrent NDD in patients diagnosed with BPH, and to correlate the presence of NDD with treatment outcome.

MATERIALS AND METHODS

28 men, mean age 66.4 years, referred by urologists at the outpatient clinic as BPH (initial diagnosis: BPH alone, 24, BPH and NDD, 4) with regards to digital examination and lower urinary tract symptoms, underwent urodynamic study and neurological examination. MRI scans were performed to confirm the diagnosis.

RESULTS

Urodynamic study (except for 2, acontractile detrusor (AD)) showed equivocal obstruction (EO), 6; underactive detrusor (UD), 9 (voiding phase); detrusor overactivity (DO), 12; urethral relaxation, 1, and reduced sensation, 5 (filling phase). EO correlated with the presence of UD (p = 0.03). DO did not correlate with the prostate size or urodynamically-defined outlet obstruction. Reduced sensation was common in patients >65 years of age (p = 0.05). Neurological examination/imaging showed exaggerated reflexes, 1; decreased reflexes, 6; multiple cerebral infarction, 8; cervical spondylosis, 1 (in patients with DO); lumbar spondylosis, 5 (in patients with AD/UD), and the final diagnosis was made: definite BPH, 6; probable BPH, 9; BPH and NDD, 13, and NDD were common in the patients aged >65 years (p = 0.015). Transurethral prostatectomy and alpha-blocker were mostly successful, but the failure rate was reported in definite BPH, none, probable BPH, 29%, and BPH and NDD, 33%.

CONCLUSIONS

BPH patients, particularly those >65 years of age, commonly have NDD. Multiple cerebral infarction (upper neuron disorder) and lumbar spondylosis (lower neuron disorder) might contribute to DO and UD, respectively. A uro-neurological assessment is important to select typical BPH patients for maximizing therapeutic benefit.

Regional differences in responses of rabbit detrusor to electrical and adrenergic stimulation: influence of outlet obstruction

OBJECTIVE

To examine regional responses of control and obstructed rabbit detrusor strips to electrical and adrenergic stimulation, and determine whether outlet obstruction causes regional variations in blood flow throughout the detrusor, as the detrusor smooth muscle of the bladder body has previously been considered homogeneous in its pharmacological properties.

MATERIALS AND METHODS

Fourteen male rabbits had the bladder outlet surgically obstructed for 2 weeks and were compared with 10 unoperated control rabbits. Blood flow was measured with the bladder empty and at capacity, using fluorescent microspheres. Paired dorsal and ventral strips were harvested from the midline equatorial detrusor and electrically and adrenergically stimulated.

RESULTS

Obstructed rabbits had significantly higher bladder capacities and bladder weights than control rabbits. Dorsal strips from both control and obstructed rabbits contracted in response to noradrenaline, whereas ventral strips relaxed. The addition of prazosin, a nonselective alpha1-adrenergic-receptor blocker, completely blocked the contraction in dorsal strips, but had no effect on responses of ventral strips. There was also a regional difference in response to electrical stimulation, with ventral strips generating significantly more tension than dorsal strips in both control and obstructed rabbits. There were no regional differences in detrusor blood flow. Obstruction resulted in significantly lower responses to all forms of stimulation, and significantly less blood flow throughout the detrusor.

CONCLUSION

There are regional differences in adrenergic receptor function and response to electrical-field stimulation throughout control and obstructed rabbit detrusor, a region that was previously thought to be functionally homogeneous. These differences must be recognized and acknowledged to obtain accurate and reproducible data from in vitro studies of the bladder.

Single-blind, randomized controlled study of the clinical and urodynamic effects of an alpha-blocker (naftopidil) and phytotherapy (eviprostat) in the treatment of benign prostatic hyperplasia

AIM

The aim of our study was to examine the efficacy of naftopidil in terms of the international prostate symptom score (IPSS) and urodynamic parameters in the treatment of benign prostatic hyperplasia (BPH). Eviprostat was used as a control to study the efficacy of naftopidil.

METHODS

Forty-nine patients with BPH (mean age 67.9 +/- 7.8 years) were involved in the study. Patients were randomly assigned either to the naftopidil group, which was treated with the alpha-blocker naftopidil (50-75 mg daily, 36 patients), or the eviprostat group, which was treated with phytotherapy (six tablets of eviprostat daily, 13 patients).

RESULTS

The mean total IPSS, the total storage and voiding symptom scores, and the quality of life score decreased significantly (P < 0.0001 for each variable) in the naftopidil group, but not in the eviprostat group. In the naftopidil group, analyses showed significant increases in average and maximum flow rate and bladder capacity at first desire to void (P < 0.001, P = 0.001 and P = 0.024, respectively), and significant decreases in the postvoid residual, the percent of residual and the Abrams-Griffiths number (P = 0.009, P = 0.008 and P = 0.042, respectively). However, in the eviprostat group, no significant changes were noted in terms of these symptomatic and urodynamic parameters. In the pressure/flow study, an improvement in the International Continence Society nomogram grade was noted in 29% of the naftopidil group, but in only 16% of the eviprostat group. Among the 14 patients in the naftopidil group, detrusor overactivity disappeared in 21% and cystometric capacity increased in 36%, but no improvement in detrusor overactivity was noted in the eviprostat group.

CONCLUSIONS

Naftopidil appears to have been effective in this short-term treatment of BPH.

Usefulness of tamsulosin hydrochloride and naftopidil in patients with urinary disturbances caused by benign prostatic hyperplasia: a comparative, randomized, two-drug crossover study

BACKGROUND

The aim of the study presented here was to stratify drug therapy for patients with benign prostatic hyperplasia (BPH) displaying various voiding symptoms.

METHODS

Two different alpha1-adrenoceptor antagonists; tamsulosin hydrochloride (Tam) and naftopidil (Naf ), were administered to 96 patients with BPH for 8 weeks in a crossover study.

RESULTS

With the administration of both drugs, the International Prostate Symptom Score (I-PSS) significantly decreased and the maximum urinary flow significantly increased. Whereas Naf monotherapy decreased the I-PSS for storage symptoms, Tam monotherapy decreased the I-PSS for voiding symptoms. In both the Naf-to-Tam and Tam-to-Naf groups, crossover was effective when the initial drug was judged subjectively and objectively to have been ineffective. Compliance was acceptable with both drugs.

CONCLUSION

Our results show that either Naf or Tam can be used to treat patients on the basis of objective and subjective assessment of voiding symptoms. Our findings should be helpful for patient guidance and treatment of BPH.

Increased adrenergic contractility and decreased mRNA expression of NOS III in aging rat urinary bladders

Our objective was to study age-related changes in adrenergic contractility and gene expression profile in the rat urinary bladder. Young (3-month old), adult (10-month old) and senescent (30-month old) male WAG/Rij rats were used. Gene expression profile in the rat urinary bladder was defined using Atlas microarray technology. In vitro contractile responses induced by KCl, phenylephrine (PHE) and norepinephrine (NE) were compared in isolated urinary bladders dissected from young, adult and senescent rats. Among a total of 1176 genes present on the arrays, 15 genes showed an increase in expression and 10 genes a decrease with age. Four genes related to nerve growth factor were upregulated whereas NOS type III was downregulated in aging rats. Intrinsic contractility of isolated rat urinary bladders was not changed between adult and aging rats as judged by the response curves to KCl. In contrast, an age-related increase in the maximal contractile responses to NE, but not PHE, was noticed (13 +/- 1, 48 +/- 2% and 59 +/- 2% at 3, 10 and 30 months, respectively). The alpha1D-adrenoceptor antagonist BMY7378 antagonized NE-induced contractions with low potency in both groups suggesting the involvement of the alpha1A-adrenoceptor subtype. This was confirmed by microarray, which demonstrated mRNA expression for the alpha1A-adrenoceptor subtype only. These results suggest that aging of the urinary bladder is associated with an increase in the maximal contractile response to NE which could be due to NO shortage resulting from downregulation of urothelial NOS III.

Functional development of the rat urinary bladder after pre- or postpubertal castration

Experiments were done to evaluate the role of sex hormones in the functional development of the rat urinary bladder. Rats were orchiectomized or ovariectomized at 30 (prepubertal) or 70 (postpubertal) days of age and bladders were removed 1 month later. An additional group of immature male and female rats was used in which the bladders were removed at 30 days of age. There were only minor differences in contractile responses of bladder strips from any group to electrical field stimulation, ATP, carbachol, or KCl compared to age-matched controls. There were no differences in responses of bladder strips from immature females or males to the adrenergic agonists, isoproterenol, norepinephrine, or methoxamine. Bladders from the pre- and postpubertally castrated rats and their controls relaxed fully in response to isoproterenol, but strips from prepubertally castrated rats relaxed significantly less in response to norepinephrine than those from other groups. Approximately one half of the bladder strips from prepubertally castrated rats failed to relax by at least 50% in response to norepinephrine; these same strips responded to methoxamine with exaggerated contractions. Our data indicate that the normal development of rat bladder alpha-adrenergic responsiveness is adversely altered by prepubertal castration. We postulate that this may result from an alteration in the relative expression of alpha(1)-adrenergic receptor subtypes.