alpha1-adrenergic receptors in the lower urinary tract and vascular bed: potential role for the alpha1d subtype in filling symptoms and effects of ageing on vascular expression

Prospective analysis of anatomic features predisposing patients to intraoperative floppy iris syndrome

PURPOSE

To aid preoperative risk assessment by identifying anatomic parameters corresponding with a higher risk of intraoperative floppy iris syndrome (IFIS) during cataract surgery.

METHODS

Prospective cohort study of 55 patients with α1-adrenergic receptor antagonist (α1-ARA) treatment and 55 controls undergoing cataract surgery. Anterior segment optical coherence tomography (AS-OCT), video pupilometer, and biometry measurements were performed preoperatively and analyzed regarding anatomic parameters that corresponded with a higher rate of IFIS. Those statistically significant parameters were evaluated with logistic regression analysis and receiver operating characteristic (ROC) curve.

RESULTS

Pupil diameter was significantly smaller in patients who developed IFIS compared to those who did not develop IFIS (AS-OCT 3.29 ± 0.85 vs. 3.63 ± 0.68, p = 0.03; Pupilometer 3.56 ± 0,87 vs. 3.95 ± 0.67, p = 0.02). Biometric evaluation revealed shallower anterior chambers in the IFIS group (ACD 3.12 ± 0.40 vs. 3.32 ± 0.42, p = 0.02). Cutoff values for 50% IFIS probability (p = 0.5) were PD = 3.18 mm for pupil diameter and ACD = 2.93 mm for anterior chamber depth. ROC curves of combined parameters were calculated for α1-ARA medication with pupil diameter and anterior chamber depth, which yielded an AUC of 0.75 for all IFIS grades.

CONCLUSION

The combination of biometric parameters with history of α1-ARA medication can improve assessment of risk stratification for IFIS incidence during cataract surgery.

Silodosin as a predisposing factor of intraoperative floppy iris syndrome (IFIS): an observational propensity score-matching cohort study

PURPOSE

To evaluate the correlation between silodosin and intraoperative floppy iris syndrome (IFIS) and compare it with other a1-adrenergic receptor antagonists (a1-ARAs) and other factors predisposing to IFIS.

METHODS

From the patients who underwent phacoemulsification between 2014 and 2020, we identified all patients who, during their preoperative assessment, reported an a1-ARAs intake (exposed group). These patients were matched utilizing a propensity score matching analysis with an otherwise homogenous group of patients (control group) based on demographics and systemic/ocular comorbidities.

RESULTS

A total of 350 patients were included in each group. In the exposed group, 177 (50.6%) patients were exposed to tamsulosin, 105 (30%) to alfuzosin, 43 (12.2%) to silodosin. Regarding IFIS, it was observed in 21.5% of patients on tamsulosin (38/177), 11.4% on alfuzosin (12/105), 37.2% on silodosin (16/43), and 3.4% in the controlled group (12/350). In a multiple regression model analysis, the only two factors significantly associated with IFIS development were silodosin and tamsulosin yielding an adjusted odds ratio of 8.471 (95%CI 4.005-17.920) and 3.803 (95%CI 2.231-6.485), respectively.

CONCLUSION

Silodosin has been demonstrated as a predisposing factor, strongly correlated with IFIS development. These results should increase cataract surgeons' awareness to assess their patients preoperatively for exposure to silodosin carefully and employ the appropriate prophylactic measures to ameliorate the impact of silodosin intake on the surgical outcome.

Efficacy and tolerability of doxazosin gastro-intestinal therapeutic system versus tamsulosin in patients with lower urinary tract symptoms associated with benign prostatic hyperplasia: A systematic review and meta-analysis

BACKGROUND

Alpha1-adrenoceptor antagonists (α1-blockers) are first-line drugs for the treatment of lower urinary tract symptoms associated with benign prostate hyperplasia (BPH). Doxazosin gastrointestinal therapeutic system (GITS) and tamsulosin belong to the 2 most frequently prescribed α1-blockers. This systematic review and meta-analysis was performed to compare the efficacy and tolerability of these 2 α1-blockers.

METHODS

A systematic review of published randomized controlled trials in English or Chinese language was performed using the PubMed, EMBASE, Cochrane Library, CNKI, Wanfang, and Vip databases. After data extraction and quality assessment, the meta-analysis was performed to compare clinical parameters (International Prostate Symptom Score [IPSS] total [IPSS-T], storage [IPSS-S], voiding [IPSS-V], maximum urine flow [Qmax], and postvoid residual) and adverse events (AEs) that changed after first drug intake.

RESULTS

After the screening, 8 eligible randomized controlled trials with 1316 patients were identified. Doxazosin-GITS showed a significantly higher efficacy compared with tamsulosin (IPSS-T P < .001, IPSS-S P < .001, and IPSS-V P < .001). There were no significant differences between the 2 drugs for changes in Qmax (P = .477) or postvoid residual (P = .739). The overall AEs were significantly lower in the doxazosin-GITS group (risk ratio: 0.77; 95% CI: 0.54-1.08; P = .036). However, dizziness (P = .387), headache (P = .745), asthenia (P = .693), postural hypotension (P = .114), and retrograde ejaculation (P = .187) were similar between the 2 groups.

CONCLUSIONS

This meta-analysis indicates that doxazosin-GITS has significantly higher efficacy and lower AEs than tamsulosin in patients with lower urinary tract symptoms/benign prostate hyperplasia.

Piperazine-Derived α1D/1A Antagonist 1- Benzyl-N- (3-(4- (2-Methoxyphenyl) Piperazine-1-yl) Propyl) -1H- Indole-2- Carboxamide Induces Apoptosis in Benign Prostatic Hyperplasia Independently of α1-Adrenoceptor Blocking

Previous studies have indicated that α_1D/1A antagonist naftopidil (NAF) suppresses prostate growth by decreasing cell proliferation without affecting apoptosis and prostate volume in benign prostatic hyperplasia (BPH). A NAF-derived α1D/1A antagonist 1- benzyl-N-(3-(4-(2-methoxyphenyl) piperazine-1-yl) propyl)-1H-indole-2- carboxamide (HJZ-12) has been reported from our laboratory, which exhibits high subtype-selectivity to both α_1D- and α_1A- AR (47.9- and 19.1- fold, respectively) with respect to a1B-AR in vitro. However, no further study was conducted. In the present study, a pharmacological evaluation of HJZ-12 in BPH was performed on an estrogen/androgen-induced rat BPH model and human BPH-1 cell line. In vivo, HJZ-12 exhibited better performance than NAF in preventing the progression of rat prostatic hyperplasia by not only decreasing prostate weight and proliferation (similar to NAF) but also, shrinking prostate volume and inducing prostate apoptosis (different from NAF). In vitro, HJZ-12 exhibited significant cell viability inhibition and apoptotic induction in BPH-1 cell line, without presenting cell anti-proliferation properties. Intriguingly, the role of HJZ-12 on cell viability and apoptosis was an α1-independent action. Furthermore, RNA-Seq analysis was applied to screen out six anti-apoptotic genes (Bcl-3, B-lymphoma Mo-MLV insertion region 1 [Bmi-1], ITGA2, FGFR3, RRS1, and SGK1). Amongst them, Bmi-1 was involved in the apoptotic induction of HJZ-12 in BPH-1. Overall, HJZ-12 played a remarkable role in preventing the progression of prostatic hyperplasia through α1-independent apoptotic induction, indicating that it will be a multi-target effective candidate for BPH treatment.

Intraoperative Floppy Iris Syndrome: Updated Perspectives

Almost fifteen years since its initial description, intraoperative floppy iris syndrome (IFIS) during phacoemulsification surgery remains a challenge for cataract surgeons in all its key aspects that include the stratification of the preoperative risk, preoperative prophylaxis treatment, surgery design and intraoperative management. Since its original association with tamsulosin intake, IFIS has been positively correlated with a plethora of risk factors which include: gender, age, hypertension, other a1-adrenergic receptor antagonists, finasteride, angiotensin II receptor inhibitors, benzodiazepines, antipsychotics, hypertension drugs and decreased dilated pupil diameter. The assessment and stratification of the preoperative risk is pivotal in screening patients prone to develop IFIS. For these patients, it is essential that preoperative prophylaxis, employment of necessary measures and surgical technique modifications are considered. A multidisciplinary approach of IFIS is a mandate, thus ophthalmologists, urologists and sometimes other specialties should cooperate to “educate” each other about the risks of their respective fields. They both must be aware of the joint statement on IFIS by the American Academy of Ophthalmology and the American Society of Cataract and Refractive Surgery which suggests either the initiation of tamsulosin after phacoemulsification or the use of a non-selective a1-ARA for benign prostatic hyperplasia treatment. In conclusion, awareness of the risk factors associated with IFIS and their detailed preoperative documentation is crucial in addressing IFIS. The lack of such an awareness can turn a routine, uneventful surgery into one with significant visual morbidity.

The Effects of Systemic Alfuzosin and Tamsulosin Hydrochloride on Choroidal Thickness and Pupil Diameter Sizes in Cases with Benign Prostatic Hyperplasia

PURPOSE

To compare the effects of alfuzosin hydrochloride and tamsulosin hydrochloride on choroidal thickness (CT) and pupil diameter (PD) sizes in patients with benign prostatic hyperplasia.

SUBJECTS AND METHODS

Sixty-three men patients with newly diagnosis of benign prostatic hyperplasia were randomly assigned to either alfuzosin hydrochloride or to tamsulosin hydrochloride groups in this prospective, randomized, parallel-group clinical trial. Enhanced depth imaging spectral-domain optical coherence tomography, pupillography were obtained at baseline, 1st and 3rd month, and choroidal thicknesses and pupil diameter sizes were compared between the two groups.

RESULTS

The mean subfoveal choroidal thickness (SCT), nasal choroidal thickness (NCT), and temporal choroidal thickness (TCT) in AH group were 275.70 ± 32.14 μm, 269.7 ± 33.54 μm and 270.71 ± 33.52 μm at baseline, respectively; and they were 275.46 ± 31.6 μm, 268.73 ± 33.08 μm and 270.73 ± 33.05 μm at baseline in TH group, respectively (P = 0.97, P = 0.84, P = 0.99, for SCT, NCT, and TCT, respectively). The mean SCT, NCT, and TCT after 3 months were 278.93 ± 34.58 μm, 272.62 ± 34.17 μm, and 273.6 ± 34.17 μm in AH group, respectively; and they were 274.36 ± 31.91 μm, 264.70 ± 33.59 μm, and 267.72 ± 33.6 μm in TH group, respectively (P = 0.6, P = 0.37, P = 0.43, for SCT, NCT, and TCT, respectively). The mean scotopic pupil diameter (SPD), mesopic pupil diameter (MPD), and photopic pupil diameter (PPD) sizes in AH group were 6.46 ± 0.84 mm, 5.07 ± 0.72 mm and 3.66 ± 0.46 mm at baseline, respectively; and they were 6.44 ± 1.14 mm, 5.01 ± 0.79 mm and 3.62 ± 0.53 mm at baseline in TH group, respectively (P = 0.89, P = 0.74, P = 0.68, for SPD, MPD, and PPD, respectively). The mean SPD, MPD, and PPD sizes after 3 months were 5.96 ± 0.76 mm, 4.67 ± 0.74 mm, and 3.15 ± 0.47 mm in AH group, respectively; and they were 6.42 ± 0.89 mm, 5.05 ± 0.75 mm, and 3.55 ± 0.53 mm in TH group respectively (P = < 0.001, P = < 0.001, P = < 0.001, for SPD, MPD, and PPD, respectively).

CONCLUSION

The repeated measure of ANOVA for the mean CT values within AH group showed statistically significant increases in baseline CTs, although these differences did not reach statistical significance between 2 groups at follow-ups. We found significant different outcomes for PD sizes during study in the groups. The mean outcome in this study is that using αAR antagonists have potential effects on CT and PD sizes. Abbreviations and Acronyms: AH: alfuzosin hyrdrochloride; ANOVA: analyses of variance; AR: adrenergic receptor; BCVA: best-corrected visual acuity; BPH: benign prostatic hyperplasia; CT: choroidal thickness; EDI-OCT: enhanced depth imaging spectral-domain optical coherence tomography; IFIS: intraoperative floppy iris syndrome; MPD: mesopic pupil diameter; NCT: nasal choroidal thickness; PD: pupil diameter; PPD: photopic pupil diameter; SCT: subfoveal choroidal thickness; SPD: scotopic pupil diameter; TCT: temporal choroidal thickness; TH: tamsulosin hydrochloride.

Design, Synthesis, and Biological Evaluation of Novel Tetrahydroprotoberberine Derivatives (THPBs) as Selective α1A-Adrenoceptor Antagonists

A novel series of tetrahydroprotoberberine derivatives (THPBs) were designed, synthesized, and evaluated as selective α_1A-adrenergic receptors (AR) antagonists for the treatment of benign prostatic hyperplasia. On the basis of the pharmacophore model of the marketed drug silodosin, THPBs were modified by introducing an indole segment into their core scaffolds. In calcium assays, 7 out of 32 compounds displayed excellent antagonistic activities against α_1A-ARs, with IC₅₀ less than 250 nM. Among them, compound (S)-27 had the most potent biological activity; its IC₅₀ toward α_1A-AR was 12.8 ± 2.2 nM, which is 781 and 20 times more selective than that toward α_1B- and α_1D-AR, respectively. In the functional assay using isolated rat tissues, compound (S)-27 inhibited norepinephrine-induced urethra smooth muscle contraction potently (IC₅₀ = 0.5 ± 0.3 nM), without inhibiting the aortic contraction (IC₅₀ > 1000 nM), displaying a better tissue selectivity than the marketed drug silodosin. Additional results of preliminary safety studies (acute toxicity and hERG inhibition) and pharmacokinetics studies indicated the potential druggability for compound (S)-27 which is a promising lead for the development of selective α_1A-AR antagonists for the treatment of BPH.

Drug interactions between antiretrovirals and drugs used to treat benign prostatic hyperplasia/lower urinary tract symptoms

INTRODUCTION

Significant advances in antiretroviral (ARV) therapy have transformed HIV into a chronic manageable disease. Co-morbidities associated with aging, such as benign prostatic hyperplasia (BPH), are becoming increasingly prevalent in the HIV-infected population. The pharmacological treatment of BPH involves medications mainly metabolized by CYP 450 enzymes, while many ARVs have inducing or inhibiting effects on the CYP 450 system. Consequently, there is potential for significant pharmacokinetic (PK) interactions between these two classes of medications.

AREAS COVERED

This article reviews the pharmacology and metabolism of selected BPH drug therapies and ARVs, in addition to highlighting potential interactions between these two drug categories. The authors also present PK evidence of interactions from available clinical trials, product monographs and international conference abstracts. Potentially significant drug interactions are summarized and strategies for management are discussed.

EXPERT OPINION

Drugs most likely to interact with BPH medications include protease inhibitors, the non-nucleoside reverse transcriptase inhibitors efavirenz, nevirapine, etravirine, and the cobicistat-boosted integrase inhibitor elvitegravir. Clinically significant PK interactions with BPH medications and dolutegravir, raltegravir, rilpivirine, or the investigational agent doravirine do not appear to exist. Clinicians working with HIV-infected individuals need to recognize the potential for interactions involving BPH and ARV treatments to ensure effective and safe drug therapy use.

Primary Care Evaluation and Treatment of Men With Lower Urinary Tract Symptoms

Lower urinary tract symptoms (LUTS) affect 50% to 90% of men aged 50 years or older. Primary care physicians should be knowledgeable about the diagnosis and management of this condition. The authors performed detailed PubMed searches using the terms lower urinary tract symptoms, benign prostatic hyperplasia, benign prostatic enlargement, and overactive bladder. The authors then reviewed the relevant literature on the evaluation and treatment of men with LUTS. According to the literature, accurate recognition of LUTS is predicated on a focused history and physical examination, as well as serum prostate-specific antigen measurement and urinalysis. For patients with mild symptoms, watchful waiting with ongoing monitoring and lifestyle modifications may be appropriate. For patients with moderate to severe symptoms, pharmacologic therapy is effective. When substantial LUTS persist despite appropriate pharmacologic therapy, specialty urologic evaluation and treatment is warranted.

α(1)-Adrenoceptors in the urinary tract

α(1)-Adrenoceptors have been identified and characterized extensively by functional, radioligand-binding, and molecular biological techniques. Molecular clones have been isolated for three α(1)-subtypes (α(1a), α(1b), and α(1d)), and these subtypes are also functionally characterized. α(1)-Adrenoceptors are present in the prostate, urethra, bladder (urothelium, smooth muscle, and afferent nerves), ureter, vas deferens, peripheral ganglia, nerve terminals, vascular tissues, and central nervous system (CNS), and they could all potentially influence overall urinary function and contribute to both the therapeutic and adverse effects of α(1)-adrenoceptor antagonists in patients with benign prostatic hyperplasia (BPH) and lower urinary tract symptoms (LUTS). This review aimed to discuss the relevant physiological and pharmacological roles and molecular biology of α(1)-adrenoceptor subtypes in the prostate, urethra, bladder, ureter, and CNS.

Subtypes of alpha1-adrenoceptors in BPH: future prospects for personalized medicine

The alpha(1)-adrenoceptors (alpha(1)-ARs) are involved in regulation of prostatic smooth muscle tone, and are a critical mediator of lower urinary tract symptoms and pathophysiology in benign prostatic hyperplasia (BPH). As a result, alpha(1)-AR antagonists are now used as first-line medical treatment for BPH. Three alpha(1)-AR subtypes (alpha(1a)-AR, alpha(1b)-AR, alpha(1d)-AR) have been identified on the basis of results of pharmacological and molecular cloning studies; however, the precise physiological role of individual alpha(1)-AR subtypes remains elusive. The expression levels of alpha(1)-AR subtypes in the prostate differ between patients, and individual differences in the genetic background of patients with BPH might be associated with variation in responses to subtype-selective alpha(1)-AR antagonists. In addition, single nucleotide polymorphism and microarray-based gene expression profiling studies might provide an opportunity to identify markers that predict clinical response and therapeutic tolerance to alpha(1)-AR antagonists. Further genomic studies will refine our knowledge of the functions of alpha(1)-AR subtypes, lead to new strategies for the clinical management of BPH and, perhaps, enable personalized treatment of BPH in the future.

Biomarkers for benign prostatic hyperplasia progression

Despite the fact that almost all men will develop symptoms associated with benign prostatic hyperplasia within their lifetimes, no molecular markers for the disease or its likelihood to progress have been established. A marker of this type could be used to stratify patients into subpopulations as well as to identify individuals whose disease is most likely to progress. Several molecular biomarkers have high potential to fulfill these needs, although none is currently approved for the clinical setting. The future does look promising as research to find novel biologic biomarkers is progressing while existing markers are optimized and validated for clinical use.

A meta-analysis of the vascular-related safety profile and efficacy of alpha-adrenergic blockers for symptoms related to benign prostatic hyperplasia

OBJECTIVES

To evaluate the safety profile and efficacy of alpha1-adrenergic receptor blockers (A1Bs) currently prescribed for benign prostatic hyperplasia (BPH).

DATA SOURCES

A systematic literature search of MEDLINE, the Cochrane Database and the Food and Drug Administration Web site through December 2006 identified double-blinded, prospective, placebo-controlled trials, evaluating agents commercially available by prescription for the symptomatic treatment of BPH.

REVIEW METHODS

Data were reviewed by two investigators with the use of a standardised data abstraction form. Studies were evaluated for methodological quality using the Jadad scale. Studies with a score of < 3 were considered of weaker methodology.

RESULTS

Of 2389 potential citations, 25 were usable for evaluation of safety data, 26 for efficacy. A1B use was associated with a statistically significant increase in the odds of developing a vascular-related event [odds ratio (OR) 2.54; 95% confidence interval (CI): 2.00-3.24; p < 0.0001]. The odds of developing a vascular-related adverse event were: alfuzosin, OR 1.66, 95% CI: 1.17-2.36; terazosin, OR 3.71, 95% CI: 2.48-5.53; doxazosin, OR 3.32, 95% CI: 2.10-5.23 and tamsulosin, OR 1.42, 95% CI: 0.99-2.05. A1Bs increased Q(max) by 1.32 ml/min (95% CI: 1.07-1.57) compared with placebo. Difference from placebo in American Urological Association symptom index/International Prostate Symptom Score was -1.92 points (95% CI: -2.71 to -1.14).

CONCLUSIONS

Alfuzosin, terazosin and doxazosin showed a statistically significant increased risk of developing vascular-related events compared with placebo. Tamsulosin showed a numerical increase that was not statistically significant. All agents significantly improved Q(max) and symptom signs compared with placebo.

Chronic prostatitis/chronic pelvic pain syndrome: role of alpha blocker therapy

INTRODUCTION

This article reviews the rationale and data supporting alpha blocker therapy for chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS), the most common and difficult prostatitis syndrome.

METHODS

Systematic review identified ten clinical trials evaluating alpha blocker therapy for patients with CP/CPPS, including five open-label or small prospective studies and five double-blinded and placebo-controlled clinical trials.

RESULTS

Encouraging results in uncontrolled and small clinical trials led to the development of reasonably powered, double-blinded, placebo-controlled, randomized clinical trials evaluating terazosin, doxazosin, tamsulosin, and alfuzosin.

CONCLUSIONS

Current data suggest that treatment-naïve and/or newly diagnosed patients appear more likely to respond than long-term, chronic refractory patients. Longer courses of treatment (12 weeks to 6 months) appear superior to shorter courses, and less selective agents appear superior to more selective alpha1 blockers. These observations outline important questions that must be answered to define optimal treatment strategies for patients with CP/CPPS.

Alpha1 Adrenoceptors in Human Urinary Tract: Expression, Distribution and Clinical Implications

Adrenergic receptors (ARs) are a class of proteins belonging to the G protein-coupled receptor family. Pharmacological and molecular studies allowed dividing ARs into three different categories: α1, α2 and β. In this review, we focused on α1 ARs and α1 AR antagonists, since α 1 ARs play an important role in the pathophysiology of a number of urinary tract (UT) dysfunctions. α1 ARs are widely expressed in human UT; in particular, the three ureter areas (distal, medial and proximal) show different patterns of receptor expression (i.e. distal > medial = proximal), giving the molecular basis for the use of α1 ARs antagonist in the expulsive therapy of distal ureter calculi. Bladder areas are characterized by important differences among trigone, detrusor and neck, the first showing a different pattern of expression compared to the other parts. Further, there are evidences of both density and subtype gender-dependent expressions. α1 ARs expression in prostate and detrusor is a widely investigated area of research, mainly due to the clinical impact of benign prostatic hyperplasia (BPH). Urethra has not been well studied in human, although it plays a role in the control of continence.

Studies carried out on α1 AR subtype expression in the UT indicate that, although the presence of each subtype is observed, α1A firstly and then α1D ARs seem to be more expressed than α1B ARs. Thus, drugs that demonstrate high α1A/D AR selectivity have drawn the researchers’ attention. As it relates specifically to the α1 AR antagonists used in the treatment of lower UT symptoms, the concept of uroselectivity has been operationally defined; indeed, in a number of recent publications uroselectivity has been defined as the degree to which a given compound inhibits norepinephrine-induced increase in urinary muscle contractions and/or its propensity to generate unwanted cardiovascular effects, such as decreases in blood pressure.

Efficacy of Tamsulosin in the Treatment of Lower Urinary Tract Symptoms (LUTS) in Women

OBJECTIVE

We attempted to determine whether tamsulosin is an efficacious therapy for the treatment of lower urinary tract symptoms (LUTS) in women.

METHODS

A total of 140 women, aged 27-69 years old with LUTS entered a randomized double-blind study comparing tamsulosin (70) versus placebo (70) for 1 month. The outcome variables were mean change from baseline of International Prostate Symptom Score (IPSS), mean change from baseline of mean and maximum urinary flow rate and any adverse effects.

RESULTS

Mean change from baseline of IPSS (standard deviation, SD) were -5.6 (6.3) in the tamsulosin group and -2.6 (6.1) in the placebo group. The difference was statistically significant (p = 0.008). Mean change from baseline of mean urinary flow rate (SD) was 0.7 (2.7) mL/second in the tamsulosin group and -0.5 (2.6) mL/second in the placebo group. The difference was also statistically significant (p = 0.013). However, the difference in mean change from baseline of maximum urinary flow rate between the two groups was not statistically significant (p = 0.506). There were two patients in the tamsulosin group who experienced dizziness and asthenia. No other adverse effect was detected.

CONCLUSION

Tamsulosin is more efficacious than placebo in the treatment of LUTS in women.

Epigenetic regulation of human alpha1d-adrenergic receptor gene expression: a role for DNA methylation in Sp1-dependent regulation

A growing body of evidence implicates alpha1-adrenergic receptors (alpha1ARs) as potent regulators of growth pathways. The three alpha1AR subtypes (alpha1aAR, alpha1bAR, alpha1dAR) display highly restricted tissue expression that undergoes subtype switching with many pathological stimuli, the mechanistic basis of which remains unknown. To gain insight into transcriptional pathways governing cell-specific regulation of the human alpha1dAR subtype, we cloned and characterized the alpha1dAR promoter region in two human cellular models that display disparate levels of endogenous alpha1dAR expression (SK-N-MC and DU145). Results reveal that alpha1dAR basal expression is regulated by Sp1-dependent binding of two promoter-proximal GC boxes, the mutation of which attenuates alpha1dAR promoter activity 10-fold. Mechanistically, chromatin immunoprecipitation data demonstrate that Sp1 binding correlates with expression of the endogenous gene in vivo, correlating highly with alpha1dAR promoter methylation-dependent silencing of both episomally expressed reporter constructs and the endogenous gene. Further, analysis of methylation status of proximal GC boxes using sodium bisulfite sequencing reveals differential methylation of proximal GC boxes in the two cell lines examined. Together, the data support a mechanism of methylation-dependent disruption of Sp1 binding in a cell-specific manner resulting in repression of basal alpha1dAR expression.

A preliminary study of JM-27: a serum marker that can specifically identify men with symptomatic benign prostatic hyperplasia

PURPOSE

Benign prostatic hyperplasia is a common disease in men that until recently was considered a single disease with varying symptoms. Our recent analysis has revealed that a molecular marker, JM-27, is able to distinguish at the tissue level between highly symptomatic individuals and those with histological disease. The goal of these studies was to determine if a serum based assay to detect JM-27 could distinguish men with different forms of benign prostatic hyperplasia.

MATERIALS AND METHODS

A serum based enzyme-linked immunosorbent assay was developed using a novel anti-JM-27 monoclonal antibody. The assay was sensitive, detecting JM-27 at the low ng/ml level within the serum. A quantitative measurement of serum JM-27 levels was performed in 68 patients. The patients consisted of 3 groups of 29 patients with asymptomatic benign prostatic hyperplasia (American Urological Association symptom score of 15 or less), 39 with symptomatic benign prostatic hyperplasia (American Urological Association symptom score 16 to 32) and 17 with confirmed prostate cancer. The assay cutoff was determined after a pilot run of samples and applied prospectively.

RESULTS

Using the determined cutoff, serum levels of JM-27 can distinguish between symptomatic and asymptomatic patient sets. The sensitivity and specificity of the assay are 90% and 77%, respectively. The presence of prostate cancer in these men does not appear to alter the marker levels.

CONCLUSIONS

The present study is believed to represent the first characterization of a serum based marker for severe benign prostatic hyperplasia.

The role of alpha-blockers in the management of lower urinary tract symptoms in prostate cancer patients treated with radiation therapy

OBJECTIVE

Radiation therapy (RT) is commonly used for the treatment of prostate cancer, either via brachytherapy or external beam, and is often accompanied by dose-related obstructive and irritative lower urinary tract symptoms (LUTS). This review will analyze the current state of knowledge of LUTS secondary to RT for prostate cancer and review treatment options for this complication.

METHODS

A review of the literature.

RESULTS

Radiation-induced effects in the lower urinary tract that result in LUTS include injury to peripheral neurons, interstitial fibrosis of the bladder, and loss of muscle fibers in the muscularis propria. LUTS are associated with a diminished quality of life and impaired sexual function. Numerous nonrandomized studies and one randomized study support the proposition that the occurrence of LUTS secondary to RT is effectively mitigated by alpha1-adrenoreceptor blockade.

CONCLUSIONS

Basic and clinical science studies as well as clinical guidelines relevant for LUTS secondary to RT suggest that the routine use of alpha1-adrenoreceptor antagonists should be considered in patients treated with RT, either prophylactically or at the earliest sign of LUTS.

Quantification of alpha1-adrenoceptor subtypes by real-time RT-PCR and correlation with age and prostate volume in benign prostatic hyperplasia patients

BACKGROUND

We used a real-time reverse transcriptase polymerase chain reaction (RT-PCR) method for quantification of each alpha(1)-adrenoceptor (alpha(1)-AR) subtype expression level, and examined whether age and prostate volume influence human prostate alpha(1)-AR subtype expression.

METHODS

Enrolled in our study were 75 men with lower urinary tract symptoms (LUTS) secondary to untreated benign prostatic hyperplasia (BPH). Real-time RT-PCR was performed using prostate biopsy specimens to quantify the expression level of each alpha(1)-AR subtype.

RESULTS

The median expression level (interquartile range) was 1.24 (0.66-2.32), 0.16 (0.10-0.33), and 1.11 (0.75-2.27) x 1,000 copies/beta-actin for alpha(1a)-, alpha(1b)-, and alpha(1d)-AR mRNA, respectively. The expression levels differed with the individual. The expression levels of alpha(1a)-AR, alpha(1d)-AR, and total alpha(1)-AR mRNA showed a significant positive correlation with patient age, but did not correlate with prostate volume.

CONCLUSION

The difference in the expression of the alpha(1)-AR subtype with the patient may be the cause of the difference in the effectiveness of several subtype-selective alpha(1)-AR antagonists from patient to patient. The increase of alpha(1)-AR mRNA expression level with age could be an important factor in the pathogenesis of clinically significant BPH.

Alpha-adrenoceptors are a common denominator in the pathophysiology of erectile function and BPH/LUTS - implications for clinical practice

A literature search of PubMed documented publications and abstracts from proceedings of scientific meetings was made to review the available data on benign prostatic hyperplasia/lower urinary tract symptoms (BPH/LUTS) and erectile dysfunction (ED) with a special focus on the role of alpha-adrenoceptors as critical mediators of pathophysiology. The reader is introduced to clinical results on the therapeutic potential of alpha-blockers alone and in combination with phosphodiesterase type 5 (PDE-5) inhibitors in the treatment of ED associated with LUTS/BPH. Epidemiological studies clearly show that an association exists between ED and LUTS/BPH. The severity of LUTS is correlated with the risk for ED. A significant number of LUTS/BPH patients are nonresponsive to the common ED treatment with PDE-5 inhibitors. As smooth muscle contractility is regulated by adrenoceptors in the corpus cavernosum, prostate and detrusor, the alpha-adrenoceptor system may be considered a common pathophysiological mediator in the development of ED and LUTS/BPH. Blockade of alpha-adrenoceptors for the treatment of BPH/LUTS may have the potential of improving sexual function. Conversely, PDE-5 inhibitors may exhibit positive effects in LUTS patients. Pilot studies on combination regimens of alpha-adrenoceptor antagonists and PDE-5 inhibitors have yielded encouraging results in LUTS patients with persistent ED. On the basis of pharmacological and clinical evidence, it is established that the alpha-adrenoceptor system plays an important role in the pathophysiology of ED and LUTS secondary to BPH. Larger trials on the combination of alpha-adrenoceptor antagonists with PDE-5 inhibitors are necessary to develop an integrated treatment approach for BPH/LUTS patients with comorbid ED.

Overactive bladder syndrome: considerations in pharmacotherapy and new perspectives

The great epidemiological relevance of the overactive bladder (OAB) syndrome and its impact on quality of life of sufferers has encouraged a growing amount of research both in basic science and in clinical fields, with the pharmacological treatment of OAB syndrome being particularly investigated. Recently a new perspective for the use of alpha-lytic drugs in the treatment of OAB syndrome has been disclosed due to encouraging anecdotal data, and to the identification of different adrenoceptor subtypes in the female lower urinary tract. Starting with a reference picture of female lower urinary tract disorders, the authors review the present pharmacological treatment of female lower urinary tract disorders, and delineate the new perspectives acquired from recent studies of adrenoceptor subtypes.

Treatment of benign prostatic hyperplasia in hypertensive men

As the proportion of the US population over the age of 65 continues to rise, it is likely that the number of individuals with concomitant benign prostatic hyperplasia and hypertension will also increase. To reduce morbidity and mortality, it is important to treat patients with hypertension optimally. Evidence from outcome trials suggests that alpha1 blockers should not be used as first-line antihypertensive therapy. Although some clinicians previously recommended alpha1 blocker monotherapy for patients with both hypertension and benign prostatic hyperplasia, the most recent American Urologic Association and Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure guidelines recommend independent treatment with the most appropriate pharmacologic agents for each condition. When treating patients with benign prostatic hyperplasia, clinicians should be aware of the potential impacts that alpha1 blockers may have on blood pressure and potential adverse events in patients who are normotensive as well as in patients with treated hypertension.

Medikament�se Therapie der weiblichen Harninkontinenz

Drug treatment for female urinary incontinence requires a thorough knowledge of the differential diagnosis and pathophysiology of incontinence as well as of the pharmacological agents employed. Pharmacotherapy has to be tailored to suit the incontinence subtype and should be carefully balanced according to efficacy and side effects of the drug. Women with urge incontinence require treatment that relaxes or desensitizes the bladder (antimuscarinics, estrogens, alpha-blockers, beta-mimetics, botulinum toxin A, resiniferatoxin, vinpocetine), whereas patients with stress incontinence need stimulation and strengthening of the pelvic floor and external sphincter (alpha-mimetics, estrogens, duloxetine). Females with overflow incontinence need reduction of outflow resistance (baclofen, alpha-blockers, intrasphincteric botulinum toxin A) and/or improvement of bladder contractility (parasympathomimetics). If nocturia or nocturnal incontinence are the major complaints, control of diuresis is obtained by administration of the ADH analogue desmopressin. Future developments will help to further optimize the pharmacological therapy for female urinary incontinence.

Role of the newer alpha, -adrenergic-receptor antagonistsin the treatment of benign prostatic hyperplasia-related lower urinary tract symptoms

BACKGROUND

Although initially introduced for the management of hypertension, alpha(1)-adrenergic-receptor antagonists (alpha1-blockers) have become the standard of care for the medical management of benign prostatic hyperplasia (BPH)-related lower urinary tract symptoms (LUTS). However, these agents have the potential to produce orthostatic hypotension and other blood pressure-related adverse effects in normotensive patients and in those receiving concurrent treatment with other antihypertensive agents. As a result, more "uroselective," less vasoactive alpha(1)-blockers have been developed.

OBJECTIVE

This article reviews current information on the role of alpha(1)-blockers in the treatment of BPH-related LUTS. The focus is on tamsulosin and alfuzosin, newer "uroselective" agents in this class that have a decreased potential for cardiovascular adverse effects.

METHODS

Relevant articles were identified through a search of the English-language literature indexed on MEDLINE and the proceedings of scientific meetings from 1976 to 2003. The search terms were benign prostatic hyperplasia treatment, alpha(1)-adrenergic-receptor blocker, uroselectivity, lower urinary tract symptoms, complications, and cardiovascular.

RESULTS

Tamsulosin has selectivity for the a alpha(1) and alpha(1d) receptor subtypes. Alfuzosin, although not receptor subtype selective, is clinically "uroselective" and does not significantly affect vascular alpha-adrenergic receptors. Both agents are efficacious in relieving LUTS and have a decreased potential for such cardiovascular adverse effects as postural hypotension. Common adverse events with these agents include dizziness and asthenia.

CONCLUSION

Based on the available data, "uroselective" alpha(1)-blockers should be considered over older, more vasoactive agents for the medical management of LUTS, particularly in patients with BPH and hypertension.

Structure–affinity studies for a novel series of homochiral naphtho and tetrahydronaphtho analogues of α1 antagonist WB-4101

A number of enantiomeric pairs of naphthodioxane, tetrahydronaphthodioxane and naphthoxy analogues of WB-4101 (1) were designed and synthesized in order to improve the selectivity profile of the parent compound, hopefully in favour of the alpha(1a)-AR with respect to the other two alpha(1) subtypes and the 5-HT(1A) receptor. The new compounds 2-8 and, in addition, the two enantiomers of 1 were tested in binding assays on the alpha(1a)-AR, alpha(1b)-AR, alpha(1d)-AR, and the 5-HT(1A) receptor. Two of them, namely the naphtho- and tetrahydronaphthodioxane derivatives (S)-2 and (S)-3, showed lower, but significantly more specific alpha(1a) affinity than (S)-1, while the two enantiomers of the 2-methoxy-1-naphthoxy analogue 6 maintained most of the very high alpha(1a) affinity of (S)-1 and its alpha(1a) versus alpha(1b) selectivity slightly increasing the alpha(1a)/alpha(1d) and alpha(1a)/5HT(1A) affinity ratios. The SAR data were evaluated in the light of known alpha(1) subtype pharmacophores and of the alpha(1a)-AR binding mode of WB-4101 resultant from literature mutagenesis studies disclosing some interesting consonances with these models.

Mechanistic insights into the role of α1-adrenergic receptors in lower urinary tract symptoms

Although alpha(1)AR antagonists have been used for more than two decades to treat lower urinary tract symptoms (LUTS), we have little understanding of the mechanistic basis of their efficacy and their role in the development of LUTS. It is clear that alpha(1)ARs play a critical role in bladder dysfunction and recent data suggest that alpha(1)AR subtype switching may play a key role in this pathophysiology, providing support for use of alpha(1)(d)AR-selective antagonists in treating irritative symptoms. This review seeks to summarize current levels of understanding in this field and discusses new concepts that suggest increased levels of complexity involving cross-talk in multiple receptor systems. Effective therapeutic modalities likely will involve increased subtype selective alpha(1)AR antagonists and other pharmacodynamic factors.

α1-Adrenergic Receptors and Their Inhibitors in Lower Urinary Tract Symptoms and Benign Prostatic Hyperplasia

PURPOSE

We provide a comprehensive overview of the role of alpha1-adrenergic receptors (alpha1ARs) as critical mediators of lower urinary tract symptoms (LUTS) and pathophysiology in benign prostatic hyperplasia (BPH), and we review the pharmacological antagonists of alpha1ARs.

MATERIALS AND METHODS

A review was performed of pertinent studies in the literature relating to the pathophysiology of LUTS and BPH, focusing on the role of alpha1ARs, and of clinical trial and practice data evaluating the different agents that inhibit these receptors.

RESULTS

Further characterization of the alpha1AR gene family indicates that 3 receptor subtypes exist in humans. Their different distribution between urinary tract and cardiovascular tissues has provided a strategy for the development of improved therapeutic agents. Since excessive activity of the alpha1aAR and alpha1dAR subtypes appears to be a common feature in symptomatic BPH and alpha1aARs are enriched in prostatic tissue, drugs that demonstrate high alpha1aAR selectivity have attracted attention. Tamsulosin, which has high affinity for alpha1aAR and alpha1dAR subtypes but not for alpha1bAR, shows efficacy similar to the nonsubtype selective agents terazosin and doxazosin. It is associated with fewer cardiovascular side effects, although it has some ejaculatory side effects. The nonsubtype selective agent alfuzosin also demonstrates efficacy and offers an enhanced side effect profile, particularly minimizing hypotension. Other agents with super selective specificity for the alpha1aAR subtype are under investigation.

CONCLUSIONS

Further advances in the treatment of LUTS associated with BPH may depend not only on receptor subtype selectivity, but also on other pharmacokinetic and pharmacodynamic factors.

A quantitative analysis of mRNA expression of alpha 1 and beta-adrenoceptor subtypes and their functional roles in human normal and obstructed bladders

PURPOSE

We compared the expression level of alpha 1-adrenoceptor (AR) subtype mRNA to that of beta-AR subtype mRNA in control and obstructed human bladders, and examined whether alpha 1-AR mediated contraction and beta-AR mediated relaxation of human detrusor muscle are altered by bladder outlet obstruction.

MATERIALS AND METHODS

A real-time quantitative reverse transcriptase-polymerase chain reaction based method was used to quantify alpha1 and beta-AR subtype mRNA expression. The contractile response to alpha-AR agonists and the relaxant effect of beta-AR agonists were examined using an isometric contraction technique.

RESULTS

The mRNA of alpha 1a, alpha 1b, alpha 1d, beta 1 and beta 2-AR mRNAs was expressed at low levels, while beta 3-AR was the most highly expressed subtype at the mRNA level in control and obstructed bladders. The expression level of alpha 1 and beta-AR subtype mRNA was not significantly different between the 2 groups. The mean contractile response to 10(-4) M phenylephrine +/- SEM was only 4.4% +/- 1.4% and 5.2% +/- 1.4% of the 10(-7) M carbachol induced contraction in the control and obstructed groups, respectively. Contractile responses to phenylephrine were not significantly increased in obstructed bladder. Isoproterenol and the beta 3-AR selective agonist L755,507 relaxed human detrusor muscle in a concentration dependent manner (10(-9) to 10(-4) M). However, the beta 1/beta 2-AR agonist dobutamine and the beta 2-AR selective agonist clenbuterol did not produce relaxation at a concentration of 10(-9) to 10(-5) M in the 2 groups.

CONCLUSIONS

These findings indicate that neither up-regulation of alpha1-ARs nor down-regulation of beta-ARs occurs and relaxation mediating beta 3-ARs are by far predominant in the human obstructed bladder. Therefore, it is not likely that bladder alpha1-ARs are responsible for detrusor overactivity and storage symptoms in patients with benign prostatic obstruction.

ABT-866, a novel alpha(1A)-adrenoceptor agonist with antagonist properties at the alpha(1B)- and alpha(1D)-adrenoceptor subtypes

N-[3-(1H-Imidazol-4-ylmethyl)phenyl]ethanesulfonamide, maleate (ABT-866) is a novel alpha(1)-adrenoceptor agent with mixed pharmacological properties in vitro. Compared to phenylephrine, ABT-866 demonstrates intrinsic activity at the alpha(1A)-adrenoceptor subtype present in the rabbit urethra (pD(2) = 6.22, with 80% of the phenylephrine response), reduced intrinsic activity at the alpha(1B)-adrenoceptor subtype in the rat spleen (pD(2)= 6.16, with 11% of the phenylephrine response), and no intrinsic activity at the rat aorta alpha(1D)-adrenoceptor subtype. ABT-866 also demonstrated antagonism at the rat spleen alpha(1B)-adrenoceptor (pA(2) = 5.39 +/- 0.08, slope = 1.20 +/- 0.12), and the rat aorta alpha(1D)-adrenoceptor (pA(2)= 6.18 +/- 0.09, slope = 0.96 +/- 0.13). This is in contrast to the weak non-selective activity seen with the alpha(1)-adrenoceptor agonist, phenylpropanolamine (2-amino-1-phenyl-1-propanol hydrochloride), and the alpha(1A/D)-adrenoceptor selective agonist 1-(2',5'-dimethoxyphenyl)-2-aminoethanol hydrochloride (ST-1059), the active metabolite of midodrine, that has been used clinically for the treatment of stress urinary incontinence. This study identifies a unique agent that may prove to be a valuable in vivo tool in testing the hypothesis that the alpha(1A)-adrenoceptor can be stimulated to contract the smooth muscle present in the urethra without evoking blood pressure elevations presumably caused by alpha(1B)- and alpha(1D)-adrenoceptor subtype involvements in the vasculature.