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

The Role of Apoptosis in Detrusor Contractility

Apoptosis has been found in bladder affected by various types of voiding dysfunction. In animal studies, higher levels of apoptosis were observed in conditions of both detrusor overactivity and underactivity than in normal bladders. However, it has been difficult to establish the exact underlying mechanism of apoptosis in these conditions and to find new therapeutic targets because the causes of voiding dysfunction are diverse and the coexistence of various types of voiding problems is common. Furthermore, the lack of studies of the human detrusor contributes to our incomplete understanding of these issues. Therefore, this revies discuss the role of apoptosis in detrusor contractility based on previous studies.

Managing Nocturia in Frail Older Adults

This review discusses the available evidence in the current evaluation and treatment of nocturia in frail older adults. No evidence specifically evaluates the use of behavioral interventions in the treatment of the frail older adult with nocturia, but their use is supported in other cohorts. Behavioral modifications and optimal management of comorbidities remain the first-line treatment for all age groups and should be emphasized in the frail due to their favorable safety profile. No studies specific to the frail older adult support the use of pharmacotherapy. Some evidence exists for the efficacy of several agents in the older adult; however, this is difficult to extrapolate to the frail, and safety concerns abound. Desmopressin may be effective in the older adult, but a high risk of hyponatremia raises concerns for its safety, and therefore it is not recommended in the frail. α-Antagonists may have limited efficacy in men with known benign prostatic hyperplasia (BPH); they are relatively well tolerated, although the risk of orthostatic hypotension in the frail should be considered. β3-agonist trials suggest limited clinical utility. Antimuscarinics are not found to be useful in this cohort and are contraindicated in the frail older adult given the ability of antimuscarinics to cause cognitive impairment, delirium, and falls. No data examine the use of nonsteroidal anti-inflammatory drugs (NSAIDs) in the frail older adult. Additionally, the American Geriatrics Society Beers Criteria recommends against the use of muscarinics in those over the age of 75 years and therefore their use is not supported.

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.

Does age alone negatively predict the outcome of sacral neuromodulation? A single-centre retrospective observational study

BACKGROUND

For patients over the age of 70 years, sacral neuromodulation (SNM) is often not considered a potential therapeutic option. We therefore report on our results from performing SNM in elderly patients ≥70 years.

METHODS

Between 01/09 and 12/18, a total of 95 patients with refractory overactive bladder (OAB) or chronic non-obstructive urinary retention underwent SNM testing at our department. In the overall sample, 20 patients were aged 70 years or older (21%, group B), and 75 patients were under 70 years old (79%, group A). The mean follow-up period was 50.2 ± 36.2 months. Pre-, peri- and postoperative parameters were compared between the two groups. Statistical analysis was carried out with SPSS 25.0 (p < 0.05).

RESULTS

The mean patient age was 53 ± 16 (17-76) years. The indications for SNM testing were OAB and retention in 51 and 49% of patients, respectively. A total of 56 patients (59%) [8 patients (40%) in group B, 48 patients (64%) in group A] had more than 50% improvement in the context of the test (stage 1), such that a permanent neuromodulator (stage 2) was implanted. A total of 14 patients, all under 70 years old except for one older female, needed to undergo revision due to defects or infection. Overall, the success rate was 58.3% for OAB and 59.6% for urinary retention. The success rates and complications in our patient group were independent of age and geriatric assessment.

CONCLUSION

SNM can also be successfully implemented in older patients.

Efficacy and Side Effects of Drugs Commonly Used for the Treatment of Lower Urinary Tract Symptoms Associated With Benign Prostatic Hyperplasia

Benign prostatic hyperplasia (BPH) is the most common benign disease of the prostate gland and is caused by benign hyperplasia of the smooth muscle cells and stromal cells in this important gland. BPH is also the most common disease underlying lower urinary tract symptoms (LUTS). The incidence of BPH increases with age and affects more than half of all men 50 years or older. BPH mainly exerts effects on urinary function and can seriously reduce a patient's quality of life. At present, treatment for BPH aims primarily to improve the quality of life and reduce the risk of BPH-related complications. Pharmacological therapy is recommended for moderate-to-severe cases of LUTS that are suggestive of BPH. A range of drugs is currently available to treat this condition, including α1-adrenoceptor antagonists, 5α-reductase inhibitors (5-ARIs), phosphodiesterase type 5 inhibitors (PDE5Is), muscarinic receptor antagonists (MRAs), β3-adrenoceptor agonists, and plant extracts. Of these, the most commonly used drugs in the clinic are α1-adrenoceptor antagonists, 5-ARIs, and combination therapy. However, these drugs exert their effects via various mechanisms and are associated with adverse reactions. The purpose of this review is to provide current comprehensive perspectives on the mechanisms of action, efficacy, and adverse reactions associated with the drugs most commonly used for the treatment of BPH.

Alterations in histamine responses between juvenile and adult urinary bladder urothelium, lamina propria and detrusor tissues

Inflammatory mediators may have a role in various lower urinary tract disorders. Histamine is known to induce significant increases in both the tension and frequency of spontaneous phasic contractions in both urothelium with lamina propria (U&LP) and detrusor muscle via the activation of H1 receptor in juvenile animal models. However, it is unclear whether age affects these contractile responses to histamine. This study assessed the histamine receptor subtypes mediating contraction in juvenile and adult porcine bladders and compared the urothelium with lamina propria and detrusor responses to histamine. Isolated tissue bath studies were conducted using strips of porcine U&LP and detrusor obtained from juvenile (6 months) and adult (3 years) animals exposed to histamine receptor agonists and antagonists. Treatment with histamine (100 µM) in U&LP of juvenile animals caused increases in baseline tension by 47.84 ± 6.52 mN/g (p < 0.001, n = 51) and by 50.76 ± 4.10 mN/g (p < 0.001, n = 55) in adult animals. Furthermore, the frequency of spontaneous phasic contractions was significantly enhanced in response to histamine in U&LP of both juvenile and adult tissues (p < 0.001 for both age groups). Treatment with an H2 agonist in U&LP of juvenile animals decreased baseline tension by 13.97 ± 3.45 mN/g (n = 12, p < 0.05), but had no effect in adult animals. Inhibition of H1 receptors resulted in significantly reduced contractile responses of U&LP and detrusor to histamine in both juvenile and adult animals (p < 0.05). Treatment with an H2 receptor antagonist significantly enhanced contractions in juvenile preparations (n = 10, p < 0.05) but had no effect in adult preparations (n = 8). In detrusor, treatment with histamine (100 µM) in juvenile tissues showed a significantly higher increase in baseline tension of 19.10 ± 4.92 mN/g (n = 51) when compared to adult tissues exhibiting increases of 8.21 ± 0.89 mN/g (n = 56, p < 0.05). The increases in the baseline tension were significantly inhibited by the presence of H1 receptor antagonists in both juvenile and adult detrusor preparations. Treatment with either the H2 receptor antagonist or agonist in detrusor had no effect on both juvenile and adult tissues. Therefore, the histamine receptor system may play an essential role in the maintenance of bladder function or in bladder dysfunction observed in some lower urinary tract disorders.

Managing autonomic dysfunction in Parkinson's disease: a review of emerging drugs

Introduction: Autonomic dysfunction is an integral part of Parkinson disease (PD) complex and can be seen both in early and advanced stages. There is a paucity of medicines available to manage autonomic dysfunction in PD and this adds to the considerable morbidity associated with the illness.Areas covered: The pathophysiology and the available therapeutic options of autonomic dysfunction seen in PD are discussed in detail. The potential targets for novel regimens are reviewed and the available literature on the drugs emerging in management of autonomic dysfunction in PD is highlighted.Expert opinion: In the current scenario, there are several drugs that can be tried for constipation viz stool laxatives, prucalopride, prokinetic agents and a high fiber diet. Bladder dysfunction has been treated with β-agonists and with mirabegron, a selective β-3 agonist, the anticholinergic side effects are minimized, and the drug has been found to be effective. Orthostatic hypotension is managed with midodrine while droxidopa is a new drug with promising efficacy. Botulinum toxin works best for management of sialorrhea, but repeated injections are needed.

Beyond neurotransmission: acetylcholine in immunity and inflammation

Acetylcholine (ACh) is best known as a neurotransmitter and was the first such molecule identified. ACh signalling in the neuronal cholinergic system has long been known to regulate numerous biological processes (reviewed by Beckmann and Lips). In actuality, ACh is a ubiquitous signalling molecule that is produced by numerous non-neuronal cell types and even by some single-celled organisms. Within multicellular organisms, a non-neuronal cholinergic system that includes the immune system functions in parallel with the neuronal cholinergic system. Several immune cell types both respond to ACh signals and can directly produce ACh. Recent work from our laboratory has demonstrated that the capacity to produce ACh is an intrinsic property of T cells responding to viral infection, and that this ability to produce ACh is dependent upon IL-21 signalling to the T cells. Furthermore, during infection this immune-derived ACh is necessary for the T cells to migrate into infected tissues. In this review, we will discuss the various sources of ACh that are relevant during immune responses and describe how ACh acts on immune cells to influence their functions. We will also address the clinical implications of this fascinating aspect of immunity, focusing on ACh's role in the migration of T cells during infection and cancer.

Evaluating the safety and potential activity of URO-902 (hMaxi-K) gene transfer by intravesical instillation or direct injection into the bladder wall in female participants with idiopathic (non-neurogenic) overactive bladder syndrome and detrusor overactivity from two double-blind, imbalanced, placebo-controlled randomized phase 1 trials

Aims

Two phase 1 trials were performed in healthy women with the overactive bladder (OAB) syndrome and urodynamically demonstrated detrusor overactivity (DO), with the aim to demonstrate the safety and potential efficacy of URO‐902, which comprises a gene therapy plasmid vector expressing the human big potassium channel α subunit.

Methods

ION‐02 (intravesical instillation) and ION‐03 (direct injection) were double‐blind, placebo‐controlled, multicenter studies without overlap in enrollment between studies. Active doses were administered and evaluated sequentially (lowest dose first) for safety. ION‐02 participants received either 5000 µg or 10 000 µg URO‐902, or placebo. ION‐03 participants received either 16 000 or 24 000 µg URO‐902, or placebo, injected directly into the bladder wall using cystoscopy. Primary outcome variables were safety parameters occurring subsequent to URO‐902 administration; secondary efficacy variables also were evaluated.

Results

Among the safety outcomes, there were no dose‐limiting toxicities or significant adverse events (AEs) preventing dose escalation during either trial, and no participants withdrew due to AEs. For efficacy, in ION‐02 (N = 21), involuntary detrusor contractions on urodynamics at 24 weeks in patients receiving URO‐902 (P < .0508 vs placebo) and mean urgency incontinence episodes in the 5000 µg group (P = .0812 vs placebo) each showed a downward trend. In ION‐03 (N = 13), significant reduction versus placebo in urgency episodes (16 000 µg, P = .036; 24 000 µg, P = .046) and number of voids (16 000 µg, −2.16, P = .044; 24 000 µg, −2.73, P = .047) were observed 1 week after injection.

Conclusion

Promising safety and efficacy results in these preliminary phase 1 studies suggest gene transfer may be a promising therapy for OAB/DO, warranting further investigation.

Direct in vitro and in vivo demonstration of muscarinic receptor binding by the novel radioligand, [3H]5-hydroxymethyltolterodine, in the bladder and other tissues of rats

In vitro and in vivo binding sites of [³H]-labeled 5-hydroxymethyltolterodine (5-HMT), a new radioligand for labeling muscarinic receptors in rat tissues were characterized. Specific [³H]5-HMT binding in rat tissues was saturable and of high affinity in each tissue. The dissociation constant (K_d) was significantly lower in bladder and heart than in submaxillary gland. Significant levels of in vivo specific [³H]5-HMT binding by intravenous injection of the radioligand were detected in tissues, except for cerebral cortex. Thus, [³H]5-HMT was shown to specifically label muscarinic receptors in rat tissues, suggesting a useful radioligand for labeling muscarinic receptors with high affinity.

Behavioral therapy versus drug therapy in individuals with idiopathic overactive bladder: A systematic review and meta-analysis

The aim of this study was to systematically review randomized clinical trials comparing the treatment of individuals with overactive bladder syndrome through the use of behavioral therapy versus drug therapy. A systematic electronic search of MEDLINE via PubMed, Embase, and Cochrane Library was performed, including studies indexed until August 2019. Five randomized clinical trials were included. The studies presented a high risk of bias. There was no significant difference between the evaluated treatments. Thus, behavioral therapy and drug therapy also promote the improvement of the symptoms of overactive bladder syndrome, and the behavioral therapy does not have significant adverse effects reported. Due to the high risk of bias in included studies, data should be interpreted with caution. Future studies with more comprehensive protocols may change the effect estimates of behavioral therapy on overactive bladder syndrome.

Spinal glycinergic and gamma-aminobutyric acid-ergic neurons inhibit the micturition reflex after electrical stimulation of the perineum in rats with pelvic venous congestion

OBJECTIVES

To examine whether electrical stimulation of the perineum inhibited urinary frequency in rats with pelvic venous congestion, and whether electrical stimulation influences spinal glycinergic/gamma-aminobutyric acid-ergic neurons.

METHODS

Bilateral common iliac veins and bilateral uterine veins were ligated to create pelvic venous congestion rats. At 4 weeks after ligation, cystometry was carried out before and after electrical stimulation with/without intrathecal injection of strychnine (a glycine receptor antagonist) and/or bicuculline (a gamma-aminobutyric acid type A receptor antagonist). In addition, measurement of amino acid levels in the lumbosacral cord was carried out with/without electrical stimulation, and cystometry was carried out after oral administration of glycine.

RESULTS

Continuous cystometry showed that the interval between bladder contractions was shorter in pelvic venous congestion rats than in sham rats. Electrical stimulation did not change cystometric parameters in sham rats, but the interval between bladder contractions was increased by electrical stimulation in pelvic venous congestion rats. Electrical stimulation increased the levels of glutamic acid, glycine, gamma-aminobutyric acid, and taurine in the lumbosacral cord of pelvic venous congestion rats. Intrathecal strychnine abolished the effects of electrical stimulation in pelvic venous congestion rats, and intrathecal administration of both strychnine and bicuculline shortened the interval between bladder contractions more than before electrical stimulation. Oral administration of glycine (3%) to pelvic venous congestion rats increased bladder capacity.

CONCLUSIONS

Electrical stimulation of the perineum inhibits urinary frequency mainly through activation of spinal glycinergic neurons, and partly through activation of gamma-aminobutyric acid-ergic neurons in a rat model of pelvic venous congestion.

Urinary dysfunction in transgenic sickle cell mice: model of idiopathic overactive bladder syndrome

Voiding abnormalities are common among the sickle cell disease (SCD) population, among which overactive bladder (OAB) syndrome is observed at rates as high as 39%. Although detrusor overactivity is the most common cause of OAB, its molecular pathophysiology is not well elucidated. The nitric oxide (NO) signaling pathway has been implicated in the regulation of lower genitourinary tract function. In the present study, we evaluated the role of the NO signaling pathway in voiding function of transgenic SCD mice compared with combined endothelial and neuronal NO synthase gene-deficient mice, both serving as models of NO deficiency. Mice underwent void spot assay and cystometry, and bladder and urethral specimens were studied using in vitro tissue myography. Both mouse models exhibited increased void volumes; increased nonvoiding and voiding contraction frequencies; decreased bladder compliance; increased detrusor smooth muscle contraction responses to electrical field stimulation, KCl, and carbachol; and increased urethral smooth muscle relaxation responses to sodium nitroprusside compared with WT mice. In conclusion, our comprehensive behavioral and functional study of the SCD mouse lower genitourinary tract, in correlation with that of the NO-deficient mouse, reveals NO effector actions in voiding function and suggests that NO signaling derangements are associated with an OAB phenotype. These findings may allow further study of molecular targets for the characterization and evaluation of OAB.

Mechanisms underlying the effects of propiverine on bladder activity in rats with pelvic venous congestion and urinary frequency

We investigated the mechanisms by which propiverine hydrochloride influenced bladder activity in rats with pelvic venous congestion (PC) and urinary frequency. To create PC rats, female rats were anesthetized with isoflurane and the bilateral common iliac veins and bilateral uterine veins were ligated. At 4 weeks after ligation, we assessed voiding behaviour, locomotor activity, and urinary 8-hydroxydeoxyguanosine (8-OHdG) and nitric oxide metabolites (NOx). We also performed cystometry and measured mRNAs for nitric oxide synthase (NOS) and several receptors in the bladder wall. PC rats showed a decrease in locomotor activity and an increased frequency of urination. There was a decrease in endothelial NOS (eNOS), M3, and TRPV1 mRNA expression in the bladder wall, as well as an increase in inducible NOS (iNOS) mRNA. Administration of propiverine to PC rats increased locomotor activity to the level in sham rats, improved bladder function, decreased urinary 8-OHdG excretion, and increased urinary NOx excretion. In addition, propiverine increased neuronal NOS (nNOS) mRNA expression, and decreased expression of iNOS, M3 and TRPV1 mRNA in the bladder wall. Therefore, propiverine not only improved bladder dysfunction through its previously reported actions (anti-muscarinic effect, Ca antagonist effect, and inhibition of noradrenaline re-uptake), but also by reducing inflammation.

Factors Associated with Improvements in Patient-Reported Outcomes During Mirabegron or Antimuscarinic Treatment of Overactive Bladder Syndrome: A Registry Study (PERSPECTIVE)

Introduction

Patient-reported outcomes (PROs) provide valuable insights about the effectiveness of overactive bladder (OAB) treatments. The aim of PERSPECTIVE (a Prospective, non-intErventional Registry Study of PatiEnts initiating a Course of drug Therapy for overactIVE bladder) was to provide real-world evidence from the USA and Canada on patient-perceived effectiveness and safety of mirabegron and antimuscarinics for treating OAB symptoms.

Methods

This prospective, non-interventional registry followed adult patients with OAB who were starting treatment with mirabegron or antimuscarinics. All treatment decisions were made at the discretion of the treating healthcare provider with no mandatory visits after enrollment. The primary objective was to identify factors associated with improved treatment effectiveness from a patient perspective mainly using the OAB Questionnaire Short-Form (OAB-q SF). The form was sent to patients via email link at baseline and months 1, 3, 6, and 12. Treatment-emergent adverse event (TEAE) data were collated from investigator reports.

Results

Overall, 1514 patients were included (female 73.5%, mean age 62.2 years). Mirabegron was initiated by 613 patients and antimuscarinics by 901 patients. A PRO response rate of approximately 60% was achieved (575 patients did not complete baseline PROs). Similar improvements in OAB-q SF symptom bother score and health-related quality of life (HRQoL) total score were observed for mirabegron and antimuscarinic initiators. Covariate-adjusted models demonstrated that worse baseline PRO score, Hispanic ethnicity, being treatment naïve, and use of complementary/supportive OAB therapies at baseline were significantly associated with greater improvements in both scores. The most frequent TEAEs were gastrointestinal disorders (dry mouth, constipation, and nausea) and nervous system disorders (headache, somnolence, and dizziness).

Conclusion

There are no differences between mirabegron and antimuscarinics in terms of patient-reported OAB symptom bother and HRQoL.

Trial Registration

ClinicalTrials.gov identifier, NCT02386072.

Funding

Astellas Pharma Global Development, Inc.

Plain Language Summary

Plain language summary available for this article.

Electronic Supplementary Material

The online version of this article (10.1007/s12325-019-00994-7) contains supplementary material, which is available to authorized users.

Muscarinic receptor binding of fesoterodine, 5-hydroxymethyl tolterodine, and tolterodine in rat tissues after the oral, intravenous, or intravesical administration

The present study aimed to characterize muscarinic receptor binding of fesoterodine, 5-hydroxymethyl tolterodine (5-HMT), and tolterodine in bladder and other tissues of rats after their oral, intravenous, or intravesical administration. Muscarinic receptors in tissues were measured by using [N-methyl-³H]scopolamine methyl chloride ([³H]NMS). The in vitro binding affinity for muscarinic receptors was the highest by 5-HMT, followed by tolterodine and fesoterodine. Fesoterodine exhibited lower affinity in rat submaxillary gland than in detrusor muscle and urothelium. Muscarinic binding affinities of 5-HMT and tolterodine were similar among tissues. The duration of binding of oral fesoterodine to muscarinic receptors was longer in bladder than in submaxillary gland, heart, and lung, and its binding was little observed in colon and cerebral cortex. Binding activity of intravenous 5-HMT to muscarinic receptors was significantly observed in all tissues, except cerebral cortex, with a longer duration in bladder. Significant binding of bladder detrusor and urothelial muscarinic receptors was observed following intravesical instillation of 5-HMT. This selectivity may be attributed to the direct blockade of bladder receptors by excreted urinary 5-HMT. Thus, fesoterodine may be efficacious as a treatment for patients with overactive bladder.

Nociceptin/Orphanin FQ and Urinary Bladder

Following identification as the endogenous ligand for the NOP receptor, nociceptin/orphanin FQ (N/OFQ) has been shown to control several biological functions including the micturition reflex. N/OFQ elicits a robust inhibitory effect on rat micturition by reducing the excitability of the afferent fibers. After intravesical administration N/OFQ increases urodynamic bladder capacity and volume threshold in overactive bladder patients but not in normal subjects. Moreover daily treatment with intravesical N/OFQ for 10 days significantly reduced urine leakage episodes. Different chemical modifications were combined into the N/OFQ sequence to generate Rec 0438 (aka UFP-112), a peptide NOP full agonist with high potency and selectivity and long-lasting duration of action. Rec 0438 mimicked the robust inhibitory effects of N/OFQ on rat micturition reflex; its action is solely due to NOP receptor stimulation, does not show tolerance liability after 2 weeks of treatment, and can be elicited by intravesical administration. Collectively the evidence summarized and discussed in this chapter strongly suggests that NOP agonists are promising innovative drugs to treat overactive bladder.