Latest treatment for lower urinary tract dysfunction: therapeutic agents and mechanism of action

Current pharmacotherapy of overactive bladder

Overactive bladder is a symptom complex consisting of bothersome storage urinary symptoms that is highly prevalent among both sexes and has a significant impact on quality of life. Various antimuscarinic agents and the beta-3 agonists mirabegron and vibegron are currently available for the treatment of OAB. Each drug has specific pharmacologic properties, dosing schedule and tolerability profile, making it essential to individualize the medical treatment for the patient's characteristics and expectations. In this manuscript, we review the most important factors involved in the contemporary pharmacological treatment of OAB.

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.

Association between the Trp64Arg polymorphism of the ADRB3 gene and overactive bladder

BACKGROUND

The β₃ -adrenergic receptor (ADRB3) is very important in the regulation of the human detrusor muscle function. The well-known tryptophan64arginine polymorphism of the ADRB3 gene alters the response of the receptor to various stimuli, including adrenalin and noradrenalin, and may increase the susceptibility to develop overactive bladder (OAB). Therefore, this study was performed to determine whether ADRB3 Trp64Arg polymorphism is associated with the pathophysiology of OAB syndrome.

METHODS

The study group (n = 150) consists of 72 patients with OAB and 78 controls without OAB. Venous blood samples were taken from all participants to analyze the ADRB3 gene Trp64Arg polymorphism using polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP) assay. We compared the distribution of Trp64Arg polymorphism and symptom severity in both OAB and non-OAB subjects using χ² test and Mann-Whitney's U test, respectively.

RESULTS

The frequency of the 64Arg variant (heterozygous plus homozygous) in OAB and non-OAB subjects was 15.3% and 14.1%, respectively. There was no statistically significant difference between the OAB and non-OAB groups in regard to the distribution frequency of ADRB3 Trp64Arg polymorphism. The total frequency (OAB + non-OAB, 76 women and 74 men) of the Arg64 variant allele was 5.9% and 10.8% in women and in men, respectively. Although the frequency of the Arg64 variant was nearly twofold higher in men compared to women, the difference was not statistically significant.

CONCLUSIONS

These results demonstrated that the ADRB3 Trp64Arg polymorphism is not significantly associated with OAB syndrome in a sample of Turkish OAB patients.

Adding mirabegron after intravesical onabotulinumtoxinA injection improves therapeutic effects in patients with refractory overactive bladder

OBJECTIVES

To investigate whether adding an anticholinergic or beta-3 agonist can improve the therapeutic effect of intravesical onabotuliumtoxinA injection in patients with refractory overactive bladder (OAB).

METHODS

Ninety OAB patients who received an intravesical 100-U onabotulinumtoxinA injection 1 month previously were consecutively invited into a prospective, randomized, open-label study. They were randomly adding on solifenacin 5 mg daily (QD) (30 patients), mirabegron 50 mg QD (31 patients), or no medication (29 patients, control). All enrolled patients completed a 3-day voiding diary, Overactive Bladder Symptom Score (OABSS) and Urgency Severity Scale (USS) questionnaires, Global Response Assessment (GRA) scale, and uroflowmetry at baseline (1 month after intravesical onabotulinumtoxinA injection) and 3-, 6-, 9-, and 12-month follow-up. The primary end point was the effective therapeutic outcome defined as no OAB wet during the 12-month period. The secondary end point included changes of GRA, OABSS, and the parameters of the voiding diary at 3 months.

RESULTS

The baseline data were comparable among the three groups. The percentage of OAB wet in the mirabegron-added-on group was significantly less than that in the solifenacin-added-on and onabotulinumtoxinA-only groups at four different time points (P = .02). At 3 months, the changes of GRA, OABSS, USS, urge urinary incontinence, frequency, nocturia episodes, and functional bladder capacity in the mirabegron-added-on group were significantly greater than those in the other groups. No serious adverse events were reported.

CONCLUSIONS

Adding mirabegron could increase the therapeutic effects, mainly on OAB symptoms and GRA scale, after intravesical onabotulinumtoxinA injection in refractory OAB patients.

The Urothelium: Life in a Liquid Environment

The urothelium, which lines the renal pelvis, ureters, urinary bladder, and proximal urethra, forms a high-resistance but adaptable barrier that surveils its mechanochemical environment and communicates changes to underlying tissues including afferent nerve fibers and the smooth muscle. The goal of this review is to summarize new insights into urothelial biology and function that have occurred in the past decade. After familiarizing the reader with key aspects of urothelial histology, we describe new insights into urothelial development and regeneration. This is followed by an extended discussion of urothelial barrier function, including information about the roles of the glycocalyx, ion and water transport, tight junctions, and the cellular and tissue shape changes and other adaptations that accompany expansion and contraction of the lower urinary tract. We also explore evidence that the urothelium can alter the water and solute composition of urine during normal physiology and in response to overdistension. We complete the review by providing an overview of our current knowledge about the urothelial environment, discussing the sensor and transducer functions of the urothelium, exploring the role of circadian rhythms in urothelial gene expression, and describing novel research tools that are likely to further advance our understanding of urothelial biology.

Effectiveness of antimuscarinics and a beta-3 adrenoceptor agonist in patients with overactive bladder in a real-world setting

Both antimuscarinics and beta-3 adrenoceptor agonists are generally used as first-line pharmacotherapy for overactive bladder (OAB). This study aimed to investigate the differences in clinical characteristics and manifestations between different medication groups using real-world data. In this retrospective study, we recruited all patients aged > 18 years diagnosed with OAB at our institute from March 2010 to December 2017. They were allocated into three groups, the antimuscarinics (group A), beta-3 adrenoceptor agonist (group B), and discontinued (group C) treatment groups, and they completed OAB symptom score and quality of life questionnaires before and after treatment. In addition, the Clinical Global Impression was recorded for treatment outcomes. A premedication urodynamic study was also applied. A total of 215 patients were analyzed (group A: 43, B: 35, C: 137). Group B was significantly older (mean age 77.4 years) than group A (69.2 years, p = 0.012) and group C (68.6 years, p = 0.001). However, there were no significant differences in sex or underlying diseases among the groups. Before treatment, there were no significant differences in the questionnaire results among all groups. The cystometric capacity of group A (mean ± SD, 257.3 ± 135.1 cm³) was significantly larger than that of group B (125.8 ± 46.0 cm³, p = 0.002) and group C (170.5 ± 99.2 cm³, p = 0.001). After treatment, there were no significant differences between group A and group B in any of the questionnaire scores; however, their scores were better than those of group C. The OAB patients who adhered to antimuscarinics tended to be younger and have larger cystometric bladder capacity in the urodynamic study. However, there were no significant differences in effectiveness between the patients who took antimuscarinics and those who took a beta-3 adrenoceptor agonist.

The clinical pharmacology of the medical treatment for overactive bladder in adults

INTRODUCTION

Overactive bladder is a prevalent symptom complex that affects the patient's quality of life. Any disruption between the neuronal micturition pathway can lead to bladder overactivity. Neurogenic causes, myogenic causes, aging, bladder outlet obstruction, sex, and psychological factors are some of the factors contributing to bladder overactivity. The complaint of any symptoms of OAB, which is highly prevalent and affects overall QOL, often needs therapeutic interventions. When conservative therapy methods fail, the addition of medications is recommended. The most commonly used agents for the treatment of OAB are antimuscarinic drugs. New classes of drugs, such as beta-3 agonists, have enriched our pharmacologic armamentarium.

AREAS COVERED

In this review, with a special focus on oral pharmacological treatments, we discussed the definition, etiology, symptoms, diagnosis, and management of OAB.

EXPERT OPINION

OAB is a multifactorial condition with every patient presenting with a different collection of symptoms and signs. Medical therapies should be given in conjunction with behavioral therapies. Using high or low doses, flexible doses, and stopping or changing the medications are interchangeable strategies based on the level of treatment efficacy and patient satisfaction.

TAS-303 Ameliorates Carbachol-Induced Detrusor Overactivity in Rats, Revealing Its Therapeutic Potential for Overactive Bladder

Urinary incontinence is defined as an involuntary leakage of urine and is categorized into three types: stress urinary incontinence (SUI), urge urinary incontinence (UUI), and mixed urinary incontinence, which includes symptoms of SUI and UUI. As the underlying mechanisms of SUI and UUI are different, no drug is approved to treat all three types of urinary incontinence. TAS-303 is a selective norepinephrine reuptake inhibitor and has therapeutic potential for patients with SUI. In this report, we describe newly discovered pharmacological properties of TAS-303 and its effects on bladder function. Radioligand binding studies showed that TAS-303 inhibits M3 muscarinic receptor binding, with a Ki value of 547 nM. TAS-303 at 1, 3, and 10 mg/kg dose-dependently prolonged the intercontraction interval of carbachol-induced detrusor overactivity in rats, exhibiting a maximal effect that was comparable to tolterodine. These effects may result from coordinated regulation of bladder afferent activity via M3 muscarinic inhibition and β3 adrenoreceptor activation by norepinephrine elevation due to norepinephrine transporter inhibition. Moreover, TAS-303 at the effective dose for bladder function did not induce dry mouth or constipation in rats, showing that this compound may have a lower risk of antimuscarinic side effects. Thus, TAS-303 is expected to be a new profile agent with therapeutic potential for all types of urinary incontinence. SIGNIFICANCE STATEMENT: Urinary incontinence is categorized into stress, urge, and mixed urinary incontinence, but because the underlying mechanisms of each differ, no drugs are available that treat all three. TAS-303 has therapeutic potential for stress urinary incontinence. This study describes newly discovered pharmacological properties of TAS-303, which ameliorated bladder afferent activity partly via M3 muscarinic inhibition, indicating improvement in urge urinary incontinence, and highlights the potential of TAS-303 as a new therapeutic agent for all types of urinary incontinence.

Evaluation of in Vitro and in Vivo Transdermal Absorption of Solifenacin Succinate

Solifenacin (Sol), an antimuscarinic agent has been widely used for the treatment of overactive bladder. Transdermal formulations can be administered without water as well as absorbed slowly into the blood over a long period of time. The aim of this study was to develop cream and tape formulations of Sol, and evaluate the transdermal permeation and absorption of the drug from the two formulations in vitro and in vivo, respectively. In the preparation of cream formulation, Sol succinate was dissolved in purified water, and the mixture was added to the hydrophilic cream. Then, aqueous sodium hydroxide was added to the cream. In the tape formulation, Sol succinate was dissolved in a solvent with propylene glycol, diisopropanolamine, triethyl citrate, and EUDRAGIT E100. The dissolved solvent was poured onto a polyethylene film. Cream (5%) and tape (15%) formulations demonstrated high skin permeability. Addition of an adsorption enhancer (N-methyl-2-pyrrolidone) did not further increase the level of skin permeability. In subsequent in vivo experiments in rats, both the cream and tape formulations led to slow absorption of Sol into plasma, with increased t_1/2 compared with oral administration. Plasma Sol concentrations peaked 24 h after transdermal application and the drug was still detectable in plasma 72 h after application. Additionally, the cream (5%) and tape (15%) formulations resulted in a higher area under the plasma concentration vs. time curve from 0 to 72 h (AUC_0-72) compared with oral formulation (30 mg/kg). In conclusion, significant in vitro permeability and in vivo absorption of Sol from the transdermal formulations were observed.

Assessment of Anticholinergic Use After Fading of BTX-A Effects in Refractory Idiopathic Overactive Bladder: A Prospective Blinded Randomized Trial

PURPOSE

To evaluate the efficacy and safety of re-treatment with anticholinergics on refractory idiopathic overactive bladder (OAB) previously treated with intravesical botulinum neurotoxin type A (BTX-A) injections.

METHODS

One hundred patients were initially managed by intravesical injections of 100 IU of BTX-A. After the effects of BTX-A faded, patients were randomized into 2 groups: group A patients received solifenacin (10 mg) for 12 weeks (study group), while group B patients received placebo treatment for 12 weeks (control group), then subsequently received solifenacin (10 mg) for another 6 weeks. All patients underwent preoperative urodynamic testing. Patients were asked to complete the validated overactive bladder symptoms score (OABSS) and incontinence quality of life (I-QoL) instruments after the effects of intravesical BTX-A faded and at 12 weeks of follow-up. Univariate and multivariate analyses of the factors affecting treatment response were conducted.

RESULTS

At 12 weeks of follow-up, in group A, all OABSS items, including the total score, had improved significantly (P<0.0001). Group A had lower frequency and amplitude of detrusor overactivity and detrusor leak point pressure (P<0.0001, P=0.03, and P=0.01, respectively). Cystometric capacity also increased significantly (P=0.007), as did all I-QoL parameters. In a comparison of patients with failed treatment and patients with successful treatment, female sex, repeated intravesical BTX-A injections, and increased bladder capacity were statistically significant (P=0.001, P=0.0001, and P=0.002, respectively). Repeated intravesical BTX-A injections and increased bladder capacity were independent factors predicting treatment success.

CONCLUSION

In patients with refractory idiopathic OAB, reuse of anticholinergics could be an effective treatment option in patients after the effects of BTX-A fade. Repeated intravesical BTX-A injections and increased cystometric capacity could affect treatment response.

The Utilization of Benign Prostatic Hyperplasia and Bladder-Related Medications After a Transurethral Prostatectomy

OBJECTIVE

To determine how often prostate- and bladder-specific medications for lower urinary tract symptoms are used following a transurethral prostatectomy (TURP).

METHODS

This study utilized several linked, routinely collected datasets from the province of Ontario, Canada to identify men older than 66 years who underwent their first TURP between April 2003 and March 2016. The primary outcome was the probability of using at least 30 days of either prostate-specific alpha blockers (AB), 5-alpha reductase inhibitors (5ARI), or anticholinergics/beta-3 agonists (AC/B3) after their TURP.

RESULTS

We identified 58,038 men (median age 75), with a median follow-up of 4.9 years. In the 6 months prior to their TURP, AB, 5ARIs or AC/B3 were used by 62%, 32%, and 6%, respectively. Following a 90-day washout period after TURP, these medications were used by 27%, 20%, and 15% of men, respectively. The cumulative probability of using these medications within the first 10 years after TURP was 38%, 28%, and 20%, respectively. Family physicians prescribed the majority of AB, while urologists prescribed the majority of the AC/B3. Among men on AC/B3 prior to TURP, 46% used them after TURP; in multivariate cox regression analysis age ≥75, diabetes, preoperative use of AC/B3, and no preoperative urinary retention predicted postoperative utilization of AC/B3 medications.

CONCLUSION

There is considerable use of AB and 5ARIs despite a lack of evidence for using these medications after a TURP. Given the well-characterized placebo response in BPH patients, this practice should be properly evaluated for clinical efficacy.

Combination Pharmacotherapy for Treatment of Overactive Bladder (OAB)

Overactive bladder syndrome (OAB) negatively affects the quality of life of patients and their interactions with society. Treatment of OAB starts with behavioral modification and then pharmacotherapy using monotherapy with either antimuscarinics or β3 agonists. The third-line more invasive approaches are the next treatment option currently recommended. Both antimuscarinic agents and β3 agonists work through a different molecular pathway. This brings up the potential of having an additive effect when using a combination treatment for patients with OAB. Currently, the potential for using combination therapy to treat OAB in patients who had no improvement with a monotherapy approach before we attempt a more invasive approach is being explored. Several studies have shown the benefits of combination therapy which will be an additional option to the tools to treat OAB.

Elevated post-void residual volume in a geriatric post-hip fracture assessment in women-associated factors and risk of mortality

BACKGROUND AND AIM

Multiple factors contribute to elevated post-void residual urine volumes (PVR), but they may indicate detrusor underactivity (DU), especially in older women. The aim here was to examine factors associated with and prognostic significance of elevated PVR in a geriatric post-hip fracture assessment in a female population.

METHODS

Consecutive female hip fracture patients (n = 409) aged 65 years and older were included. PVR was measured by bladder scanner. PVR of 160 ml or more was deemed elevated. Age-adjusted univariate logistic regression analyses were conducted to examine the association of the domains of the comprehensive geriatric assessment (CGA) with elevated PVR. Cox proportional hazards model was used to determine the age-adjusted association of an elevated PVR with 1-year mortality.

RESULTS

Of the patients, 64 (15.6%) had elevated PVR. Having urinary or fecal incontinence, difficulties in physical activities of daily living, malnutrition, poor performance on Timed Up and Go and Elderly Mobility Scale were significantly associated with elevated PVR. Difficulties in instrumental activities of daily living, renal dysfunction, constipation, polypharmacy, nocturia, cognitive impairment and depressive mood were not associated with elevated PVR. Elevated PVR significantly increased the risk of mortality 1 year post hip fracture.

CONCLUSIONS

Elevated PVR is relatively common in older female hip fracture patients and associated with physical functioning, malnutrition and risk of mortality. Even though a causal relationship cannot be confirmed, the findings may suggest a relationship between DU and physical frailty. PVR deserves to be included in the CGA of frail older patients including women.

The efficacy of mirabegron in the treatment of urgency and the potential utility of combination therapy

Urgency is the prevalent and most bothersome symptom of overactive bladder (OAB) and the treatment of urgency is the primary objective in the management of OAB. Urgency has a major impact on other symptoms of OAB and culminates in an increased frequency of micturition and reduced volume voided, which may contribute to shorter intervals between the need to void. Antimuscarinic agents and mirabegron, a β3-adrenoceptor agonist, constitute the main oral pharmacotherapeutic options for the treatment of urgency and other OAB symptoms. The reduction of urgency and other OAB symptoms significantly improve health-related quality of life. This review will explore the distinct mechanisms of action and effects of antimuscarinic agents and mirabegron, in relation to their effect on the pathophysiology of urgency. The review will also provide an overview of the various validated measurements of urgency and the numerous clinical trials regarding antimuscarinic agent monotherapy, mirabegron monotherapy, or combination treatment with mirabegron added on to the antimuscarinic agent solifenacin. A narrative review of the literature relating to pathophysiology of urgency, the validated measurements of urgency, and clinical trials relating to the pharmacological treatment of urgency. Antimuscarinic agent monotherapy, mirabegron monotherapy, or combination treatment with mirabegron added on to the antimuscarinic agent solifenacin statistically significantly reduce the symptoms of urgency compared with placebo. Combination therapy with mirabegron added on to solifenacin also statistically significantly reduces the symptoms of severe urgency compared with antimuscarinic agent monotherapy. A critique of the clinical benefits of combination therapy is also provided. Combination therapy provides an alternative treatment in patients with OAB that includes urgency who respond poorly to first-line monotherapy and who may otherwise often move on to more invasive treatments.

The Management of Lower Urinary Tract Dysfunction in Multiple Sclerosis

PURPOSE OF REVIEW

Multiple sclerosis (MS) is the most frequent neuroinflammatory disease of the central nervous system and is commonly associated with lower urinary tract (LUT) dysfunction. As a consequence, health-related quality of life is often impaired and the upper urinary tract might be at risk for damage. The aim of this review is to give an overview of current treatment options for LUT dysfunction in patients with MS.

RECENT FINDINGS

The treatment is tailored to the type of dysfunction-storage or voiding dysfunction-beginning with conservative treatment options and ending with invasive therapies and surgery. Additionally, alternative options, e.g., different intravesical therapies or cannabinoids, have been evaluated in recent years with promising results. Current available therapies offer different possible treatments for LUT dysfunction in patients with MS. They address either voiding or storage dysfunction and therefore ameliorate LUT symptoms improve quality of life and protect the upper urinary tract.

Variation in Cardiovascular Risk Related to Individual Antimuscarinic Drugs Used to Treat Overactive Bladder: A UK Cohort Study

BACKGROUND

Blocking muscarinic receptors could have an effect on cardiac function, especially among elderly patients with overactive bladder (OAB).

STUDY OBJECTIVE

To investigate the risk of cardiovascular (CV) events in users of antimuscarinic drugs to treat OAB.

DESIGN, SETTING, AND PARTICIPANTS

Cohort study of new users of darifenacin, fesoterodine, oxybutynin, solifenacin, tolterodine, or trospium, 18 years or older, in the United Kingdom's Clinical Practice Research Datalink (CPRD), 2004-2012.

OUTCOME MEASUREMENTS AND MAIN RESULTS

Using tolterodine as the reference, we estimated propensity-score-stratified incidence rate ratios (IRRs) for acute myocardial infarction, stroke, CV mortality, major adverse cardiac events (MACE, a combined end point of the previous three), and all-cause death for individual antimuscarinic drugs. The study cohort included 119,912 new users of OAB drugs. The mean age at cohort entry was 62 years, 70% were female, and the mean follow-up was 3.3 years. The adjusted IRR for MACE and current use of oxybutynin compared with current use of tolterodine was 1.14 (95% confidence interval [CI] 1.01-1.30). In contrast, the IRR was 0.65 (CI 0.56-0.76) for current use of solifenacin compared with tolterodine. In this study, performed with health care data, the distribution of risk factors was relatively similar across users of different OAB drugs and, although our analyses controlled for a range of measured potential confounders, residual confounding cannot be ruled out.

CONCLUSIONS

In an observational comparative study of users of medications to treat OAB conducted in routine clinical practice, the risk for CV side effects was increased in users of oxybutynin and decreased in users of solifenacin compared with users of tolterodine.

Basic and clinical aspects of antimuscarinic agents used to treat overactive bladder

Antimuscarinic agents are now widely used as the pharmacological therapy for overactive bladder (OAB) because neuronal (parasympathetic nerve) and non-neuronal acetylcholine play a significant role for the bladder function. In this review, we will highlight basic and clinical aspects of eight antimuscarinic agents (oxybutynin, propiverine, tolterodine, solifenacin, darifenacin, trospium, imidafenacin, and fesoterodine) clinically used to treat urinary dysfunction in patients with OAB. The basic pharmacological characteristics of these eight antimuscarinic agents include muscarinic receptor subtype selectivity, functional bladder selectivity, and muscarinic receptor binding in the bladder and other tissues. The measurement of drug-receptor binding after oral administration of these agents allows for clearer understanding of bladder selectivity by the integration of pharmacodynamics and pharmacokinetics under in vivo conditions. Their central nervous system (CNS) penetration potentials are also discussed in terms of the feasibility of impairments in memory and cognitive function in elderly patients with OAB. The clinical aspects of efficacy focus on improvements in the daytime urinary frequency, nocturia, bladder capacity, the frequency of urgency, severity of urgency, number of incontinence episodes, OAB symptom score, and quality of life (QOL) score by antimuscarinic agents in patients with OAB. The safety of and adverse events caused by treatments with antimuscarinic agents such as dry mouth, constipation, blurred vision, erythema, fatigue, increased sweating, urinary retention, and CNS adverse events are discussed. A dose-dependent relationship was observed with adverse events, because the risk ratio generally increased with elevations in the drug dose of antimuscarinic agents. Side effect profiles may be additive to or contraindicated by other medications.

Phosphodiesterase type 4 inhibition enhances nitric oxide- and hydrogen sulfide-mediated bladder neck inhibitory neurotransmission

Nitric oxide (NO) and hydrogen sulfide (H₂S) play a pivotal role in nerve-mediated relaxation of the bladder outflow region. In the bladder neck, a marked phosphodiesterase type 4 (PDE4) expression has also been described and PDE4 inhibitors, as rolipram, produce smooth muscle relaxation. This study investigates the role of PDE4 isoenzyme in bladder neck gaseous inhibitory neurotransmission. We used Western blot and double immunohistochemical staining for the detection of NPP4 (PDE4) and PDE4A and organ baths for isometric force recording to roflumilast and tadalafil, PDE4 and PDE5, respectively, inhibitors in pig and human samples. Endogenous H₂S production measurement and electrical field stimulation (EFS) were also performed. A rich PDE4 and PDE4A expression was observed mainly limited to nerve fibers of the smooth muscle layer of both species. Moreover, roflumilast produced a much more potent smooth muscle relaxation than that induced by tadalafil. In porcine samples, H₂S generation was diminished by H₂S and NO synthase inhibition and augmented by roflumilast. Relaxations elicited by EFS were potentiated by roflumilast. These results suggest that PDE4, mainly PDE4A, is mostly located within nerve fibers of the pig and human bladder neck, where roflumilast produces a powerful smooth muscle relaxation. In pig, the fact that roflumilast increases endogenous H₂S production and EFS-induced relaxations suggests a modulation of PDE4 on NO- and H₂S-mediated inhibitory neurotransmission.

Crucial roles of nitric oxide synthases in β-adrenoceptor-mediated bladder relaxation in mice

The specific roles of nitric oxide (NO) synthases (NOSs) in bladder smooth muscle remain to be elucidated. We examined the roles of NOSs in β-adrenoceptor (AR)-mediated bladder relaxation. Male mice (C57BL6) deficient of neuronal NOS [nNOS-knockout (KO)], endothelial NOS (eNOS-KO), neuronal/endothelial NOS (n/eNOS-KO), neuronal/endothelial/inducible NOS (n/e/iNOS-KO), and their controls [wild-type (WT)] were used. Immunohistochemical analysis was performed in the bladder. Then the responses to relaxing agents and the effects of several inhibitors on the relaxing responses were examined in bladder strips precontracted with carbachol. Immunofluorescence staining showed expressions of nNOS and eNOS in the urothelium and smooth muscle of the bladder. Isoproterenol-induced relaxations were significantly reduced in nNOS-KO mice and were further reduced in n/eNOS-KO and n/e/iNOS-KO mice compared with WT mice. The relaxation in n/e/iNOS-KO mice was almost the same as in n/eNOS-KO mice. Inhibition of Ca2+-activated K+ (KCa) channel with charybdotoxin and apamin abolished isoproterenol-induced bladder relaxation in WT mice. Moreover, direct activation of KCa channel with NS1619 caused comparable extent of relaxations among WT, nNOS-KO, and n/eNOS-KO mice. In contrast, NONOate (a NO donor) or hydrogen peroxide (H2O2) (another possible relaxing factor from eNOS) caused minimal relaxations, and catalase (H2O2 scavenger) had no inhibitory effects on isoproterenol-induced relaxations. These results indicate that both nNOS and eNOS are substantially involved in β-AR-mediated bladder relaxations in a NO- or H2O2-independent manner through activation of KCa channels.

Combination therapy only shows short-term superiority over monotherapy on ureteral stent-related symptoms - outcome from a randomized controlled trial

Background

Controversy remains on the superiority of combination therapy over monotherapy on ureteral stent-related symptoms (SRSs). We tend to explore if there is a necessity of combination therapy.

Methods

One hundred cases of unilateral upper urinary tract calculi with stent insertion (pre and post flexible ureteroscopy) were randomized into 4 groups, given non-treatment, solifenacin, tamsulosin or combination respectively. Eight times of follow-ups were given after each insertion.

Results

SRSs released spontaneously within 4 days after insertion (p = 0.017) but then stay with no further improvement. Benefit of solifenacin on flank pain started showing after day4 (p = 0.002), which was comparable to that of tamsulosin and combination (p = 0.914 vs 0.195). Combination therapy showed superiority over both monotherapy before day4, but after then solifenacin and tamsulosin showed similar effectiveness with the combination therapy on both bladder pain (p = 0.229 vs 0.394) and urgency (p = 0.813 vs 0.974). No improvement on hematuria or frequency was observed in each group.

Conclusions

Combination therapy takes effect faster but shows no supervisory after the first few days compared with monotherapy.

Trial registration

The study protocol was registered on Chinese Clinical Trial Register on April 17th, 2013 (registration number: ChiCTR-TRC-13003148).

Electronic supplementary material

The online version of this article (doi:10.1186/s12894-016-0186-y) contains supplementary material, which is available to authorized users.

New therapeutic strategies for the treatment of male lower urinary tract symptoms

Male lower urinary tract symptoms (LUTS) are prevalent in the general population, especially in those of advanced age, and are characterized by notable diversity in etiology and presentation, and have been proven to cause various degrees of impairment on quality of life. The prostate has traditionally been regarded as the core cause of male LUTS. As a result, medical treatment aims to provide symptomatic relief and effective management of progression of male LUTS due to benign prostatic enlargement. In this context, α₁-blockers, phosphodiesterase-5 inhibitors, and 5α-reductase inhibitors have long been used as monotherapies or in combination treatment to control voiding LUTS. There is accumulating evidence, however, that highlights the role of the bladder in the pathogenesis of male LUTS. Current research interests have shifted to bladder disorders, and medical management is aimed at the bladder. Muscarinic receptor antagonists and the newly approved β₃-adrenergic agonist mirabegron aim to alleviate the most bothersome storage LUTS and thus improve quality of life. As voiding and storage LUTS frequently coexist, combination therapeutic strategies with α₁-blockers and antimuscarinics or β₃-agonists have been introduced to manage symptoms effectively. Anti-inflammatory agents, vitamin D₃-receptor analogs, and cannabinoids represent treatment modalities currently under investigation for use in LUTS patients. Furthermore, luteinizing hormone-releasing hormone antagonists, transient receptor-potential channel blockers, purinergic neurotransmission antagonists, Rho-kinase inhibitors, and inhibitors of endothelin-converting enzymes could have therapeutic potential in LUTS management, but still remain in the experimental setting. This article reviews new strategies for the medical treatment of male LUTS, which are dictated by the potential role of the bladder and the risk of benign prostatic hyperplasia progression. Moreover, combination treatments and therapies currently under investigation are also presented.

Urodynamic characteristics of awake rats under retrained versus freely moving condition: Using a novel model

Urodynamic investigation in conscious rats is widely employed to explore functional bladder disorders of various etiologies and pathogeneses. Rats can be placed in restraining cages or wide cabinets where they are allowed to move freely during cystometry. However, the requirements of special devices hampered the application of urodynamic test in freely moving rats, and whether the restraint has any effects on urodynamic parameters in conscious rats remains obscure. In the present study, we described a novel approach for urodynamic investigation in both restrained and freely moving conscious rats. In addition, we for the first time systematically compared the urodynamic parameters of rats in the two conditions. With the current method, we successfully recorded stable and repeatable intravesical pressure traces and collected expected reliable data, which supported the idea that the restraint does not affect the activity of the micturition reflex in rats, provided sufficient and appropriate measures could be applied during cystometry. Fewer technique problems were encountered during urodynamic examination in restrained rats than in freely moving ones. Taken together, conscious cystometry in rats placed in restraining cages with proper managements is a reliable and practical approach for evaluating the detrusor activity and bladder function.

Short-Term Flavoxate Treatment Alters Detrusor Contractility Characteristics: Renewed Interest in Clinical Use?

OBJECTIVES

Flavoxate has had a long history of use in the treatment of overactive bladder, despite the lack of documentation on its clinical efficacy and mechanism(s) of action. This study was conducted to understand how contractility characteristics of the detrusor are affected after a short period of flavoxate treatment.

METHODS

Eight-week-old mice were treated with flavoxate for 5 days and detrusor contractile responses were examined ex vivo under different pharmacological and electrical stimuli.

RESULTS

K(+) -Krebs'-induced contraction developed more slowly while 64 Hz electrical field stimulation-induced contraction developed faster in flavoxate-treated strips when compared to control. Amplitudes of maximal and steady-state contraction induced by 3 µmol/L carbachol were also larger after flavoxate treatment. Control strips showed an overall greater dependence on stimulus strength in eliciting the responses.

CONCLUSIONS

These findings provided new information of how short-term flavoxate treatment altered contractility characteristics at the bladder level, which may instill new interest in investigating the use of this drug in bladder disorders not responding well to conventional treatments.

Postmenopausal overactive bladder

Bladder storage symptoms have a severe impact on many areas as regards the quality of life including health-related, social, psychological and working functions. Pharmacotherapy of lower urinary tract stores (LUTS) has been developed to optimize neural control of the lower urinary tract in pathologic states. The bladder can be overactive or underactive. Overactive bladder (OAB) is highly prevalent and is associated with considerable morbidity, especially in aging population. Therefore, an effective treatment of OAB must result in a meaningful reduction in urinary symptoms. Pharmacotherapy for the OAB must be individualized based on the degree of bother, medication side-effect profile, concomitant comorbidities and current medication regimen. Antimuscarinic agents will continue to represent the current gold standard for the first-line pharmacological management of OAB. Alternatively to antimuscarinic therapy, β3-adrenergic receptor agonists, due to their efficacy and favorable adverse event profile, are a novel and attractive option of pharmacological treatment of overactive bladder symptoms. A combination of selective antimuscarinic and β3-adrenergic receptor agonists, agents with the different mechanism of action, gives a new treatment option for the patient with OAB according to its harms profile. A number of putative novel therapeutic agents is under clinical evaluations that may ultimately provide alternative or combination treatment options for OAB in the nearest future.

Elucidation of the Pattern of the Onset of Male Lower Urinary Tract Symptoms Using Cluster Analysis: Efficacy of Tamsulosin in Each Symptom Group

OBJECTIVE

To present a new grouping of male patients with lower urinary tract symptoms (LUTS) based on symptom patterns and clarify whether the therapeutic effect of α1-blocker differs among the groups.

METHODS

We performed secondary analysis of anonymous data from 4815 patients enrolled in a postmarketing surveillance study of tamsulosin in Japan. Data on 7 International Prostate Symptom Score (IPSS) items at the initial visit were used in the cluster analysis. IPSS and quality of life (QOL) scores before and after tamsulosin treatment for 12 weeks were assessed in each cluster. Partial correlation coefficients were also obtained for IPSS and QOL scores based on changes before and after treatment.

RESULTS

Five symptom groups were identified by cluster analysis of IPSS. On their symptom profile, each cluster was labeled as minimal type (cluster 1), multiple severe type (cluster 2), weak stream type (cluster 3), storage type (cluster 4), and voiding type (cluster 5). Prevalence and the mean symptom score were significantly improved in almost all symptoms in all clusters by tamsulosin treatment. Nocturia and weak stream had the strongest effect on QOL in clusters 1, 2, and 4 and clusters 3 and 5, respectively.

CONCLUSION

The study clarified that 5 characteristic symptom patterns exist by cluster analysis of IPSS in male patients with LUTS. Tamsulosin improved various symptoms and QOL in each symptom group. The study reports many male patients with LUTS being satisfied with monotherapy using tamsulosin and suggests the usefulness of α1-blockers as a drug of first choice.

Research Findings on Overactive Bladder

Several physiopathologic conditions lead to the manifestation of overactive bladder (OAB). These conditions include ageing, diabetes mellitus, bladder outlet obstruction, spinal cord injury, stroke and brain injury, Parkinson's disease, multiple sclerosis, interstitial cystitis, stress and depression. This review has discussed research findings in human and animal studies conducted on the above conditions. Several structural and functional changes under these conditions have not only been observed in the lower urinary tract, but also in the brain and spinal cord. Significant changes were observed in the following areas: neurotransmitters, prostaglandins, nerve growth factor, Rho-kinase, interstitial cells of Cajal, and ion and transient receptor potential channels. Interestingly, alterations in these areas showed great variation in each of the conditions of the OAB, suggesting that the pathophysiology of the OAB might be different in each condition of the disease. It is anticipated that this review will be helpful for further research on new and specific drug development against OAB.

Effects of α-Blockers, Antimuscarinics, or Combination Therapy in Relieving Ureteral Stent-Related Symptoms: A Meta-Analysis

PURPOSE

We evaluated the effects of α-blockers, antimuscarinics, or a combination of both in reducing ureteral stent-related symptoms.

METHODS

The relevant studies were identified by searching MEDLINE, EMBASE and Cochrane Library Database from January 2000 to May 2014. Randomized controlled trials evaluating effects of α-blocker, antimuscarinic, and combination therapy for stent-related symptoms were included. Two reviewers independently screened studies and extracted data.

RESULTS

A total of 13 articles were identified including 1408 patients. There were statistically significant differences in urinary symptom (-6.37; P<0.0001) and body pain index score (-7.03; P=0.0008) of the Ureteral Stent Symptom Questionnaire (USSQ), total International Prostate Symptom Score (IPSS) (-4.16; P=0.0006), Visual Analogue Pain Scale (VAPS) score (-2.48; P<0.00001), and quality of life (QoL) (-1.42; P=0.0009) in favor of the α-blocker group. Antimuscarinics alone vs the control group showed significant improvement in total IPSS (mean difference [MD]: -3.76; 95% confidence interval [CI], -5.08 to -2.43; P<0.00001) and QoL (MD: -0.82; 95% CI, -1.31 to -0.32; P=0.001). Compared with α-blockers monotherapy, combination therapy has significant lower total IPSS (MD: -3.74; 95% CI, -4.94 to -2.54; P<0.00001), VAPS (MD: -0.50; 95% CI, -0.89 to -0.11; P=0.01), and QoL (MD: -0.93; 95% CI, -1.30 to -0.55; P<0.00001).

CONCLUSIONS

Our data showed the beneficial effect of α-blockers alone and antimuscarinics alone in reducing stent-related symptoms. Furthermore, we suggested significant advantages of combination therapy of α-blocker and antimuscarinic compared with α-blocker monotherapy. However, more high quality, randomized controlled trials are warranted to better address this issue, however.

Transurethral resection of the prostate after radiotherapy for prostate cancer: impact on quality of life

OBJECTIVES

To evaluate the impact of transurethral resection of the prostate on quality of life after radiotherapy for prostate cancer.

METHODS

A group of 49 consecutive patients with and 487 without prior transurethral resection of the prostate responded to the Expanded Prostate Cancer Index Composite questionnaire before, on the last day, and a median time of 2 months and 16 months after external beam radiotherapy (70-78 Gy). A matched-pair analysis was used to avoid the influence of treatment-associated confounding factors, including dose, treatment volume and hormonal therapy.

RESULTS

Significantly smaller acute urinary score changes relative to baseline levels resulted with versus without prior transurethral resection of the prostate (mean function/bother score decrease of 3/6 vs 18/21 points at the end of radiotherapy; P < 0.01), affecting urinary incontinence (pads to control urinary leakage in 4% vs 24%; P = 0.03) and irritative/obstructive symptoms (big/moderate problem with weak urinary stream in 11% vs 37%; P = 0.02). As opposed to acute changes, transurethral resection of the prostate was a significant predisposing factor for a long-term urinary function score decrease >10 points (20% vs 6% of patients with vs without prior resection; P = 0.04). Urinary incontinence risk was higher for patients with a longer time from resection to radiotherapy.

CONCLUSIONS

Transurethral resection of the prostate significantly affects acute (considerably fewer symptoms) and long-term (relevant toxicity in some cases) urinary quality of life after radiotherapy for prostate cancer.