Cryo-EM structure of the ß3-adrenergic receptor reveals the molecular basis of subtype selectivity.

The ß3-adrenergic receptor (ß3AR) is predominantly expressed in adipose tissue and urinary bladder and has emerged as an attractive drug target for the treatment of type 2 diabetes, obesity, and overactive bladder (OAB). Here, we report the cryogenic electron microscopy structure of the ß3AR-Gs signaling complex with the selective agonist mirabegron, a first-in-class drug for OAB. Comparison of this structure with the previously reported ß1AR and ß2AR structures reveals a receptor activation mechanism upon mirabegron binding to the orthosteric site. Notably, the narrower exosite in ß3AR creates a perpendicular pocket for mirabegron. Mutational analyses suggest that a combination of both the exosite shape and the amino-acid-residue substitutions defines the drug selectivity of the ßAR agonists. Our findings provide a molecular basis for ßAR subtype selectivity, allowing the design of more-selective agents with fewer adverse effects.

Efficacy and Safety of High-Dose Vitamin D Supplementation vs Solifenacin or Standard Urotherapy for Overactive Bladder Dry in Children: A Randomized Clinical Trial.

PURPOSE: We investigated the efficacy and safety of high-dose vitamin D supplementation (VDS) plus standard urotherapy (SU) in managing overactive bladder dry in children. MATERIALS AND METHODS: A 3-arm, randomized clinical trial was performed at an academic center in China between January 2023 and June 2023. Eligible patients (n=303) were randomized to receive 8 weeks of high-dose VDS (vitamin D3 drops encapsulated as soft capsules, 2400 IU/d) plus SU (VDS + SU group; n=100), solifenacin (5-10 mg/d) plus SU (SOL + SU group; n=102), or SU alone (SU group; n=101). Reduction in voiding frequency was the primary outcome. Secondary outcomes encompassed improvement in urgency, nocturia, quality of life score, pediatric lower urinary tract symptom score, and participant satisfaction. Treatment-emergent adverse events were recorded within each group. RESULTS: Participants had a median age of 82.0 months and their baseline mean vitamin D level was 22.64 ng/mL. The VDS + SU group showed greater improvements in voids/d than the SOL + SU group (median difference 3.0; 95% CI, 2.0 to 3.5; P < .001) and the SU group (median difference 4.0; 95% CI, 3.0 to 5.0; P < .001) after intervention. The VDS + SU group also showed the greatest improvement in quality of life and pediatric lower urinary tract symptom scores. Patient satisfaction was similar between the SOL + SU and SU groups. The VDS + SU group did not exhibit a heightened risk of treatment-emergent adverse events compared to the other groups. CONCLUSIONS: High-dose VDS plus SU was effective and well-tolerated in managing overactive bladder dry in children, suggesting its potential as a novel therapeutic option for this population.

Longitudinal Fluctuations in Treatment Response After OnabotulinumToxinA and Sacral Neuromodulation for Refractory Urgency Incontinence.

PURPOSE: We compared fluctuations in treatment response after onabotulinumtoxinA and sacral neuromodulation for urgency incontinence using Markov models. MATERIALS AND METHODS: We fit data from a randomized trial to Markov models to compare transitions of success/failure over 6 months between 200 U onabotulinumtoxinA and sacral neuromodulation. Objective failure was <50% reduction in urgency incontinence episodes from baseline; subjective failure "strongly disagree" to "neutral" to the Patient Global Symptom Control questionnaire. RESULTS: Of the 357 participants (median baseline daily urgency incontinence episodes 4.7 [IQR 3.7-6.0]) 61% vs 51% and 3.2% vs 6.1% reported persistent states of objective success and failure over 6 months after onabotulinumtoxinA vs sacral neuromodulation. Participants receiving onabotulinumtoxinA vs sacral neuromodulation had lower 30-day transition probabilities from objective and subjective success to failure (10% vs 14%, ratio 0.75 [95% CI 0.55-0.95]; 14% vs 21%, ratio 0.70 [95% CI 0.51-0.89]). The 30-day transition probability from objective and subjective failure to success did not differ between onabotulinumtoxinA and sacral neuromodulation (40% vs 36%, ratio 1.11 [95% CI 0.73-1.50]; 18% vs 17%, ratio 1.14 [95% CI 0.65-1.64]). CONCLUSIONS: Over 6 months after treatment, 2 in 5 women's symptoms fluctuate. Within these initial 6 months, women receiving onabotulinumtoxinA transitioned from success to failure over 30 days less often than sacral neuromodulation. For both treatments, there was an almost 20%-40% probability over 30 days that women returned to subjective and objective success after failure. Markov models add important information to longitudinal models on how symptoms fluctuate after urgency incontinence treatment.

Structural Changes in Brain White Matter Tracts Associated With Overactive Bladder Revealed by Diffusion Tensor Magnetic Resonance Imaging: Findings From a Symptoms of Lower Urinary Tract Dysfunction Research Network Cross-Sectional Case-Control Study.

PURPOSE: Our objective was to investigate structural changes in brain white matter tracts using diffusion tensor imaging (DTI) in patients with overactive bladder (OAB). MATERIALS AND METHODS: Treatment-seeking OAB patients and matched controls enrolled in the cross-sectional case-control LURN (Symptoms of Lower Urinary Tract Dysfunction Research Network) Neuroimaging Study received a brain DTI scan. Microstructural integrity of brain white matter was assessed using fractional anisotropy (FA) and mean diffusivity. OAB and urgency urinary incontinence (UUI) symptoms were assessed using the OAB Questionnaire Short-Form and International Consultation on Incontinence Questionnaire-Urinary Incontinence. The Lower Urinary Tract Symptoms Tool UUI questions and responses were correlated with FA values. RESULTS: Among 221 participants with evaluable DTI data, 146 had OAB (66 urinary urgency-only without UUI, 80 with UUI); 75 were controls. Compared with controls, participants with OAB showed decreased FA and increased mean diffusivity, representing greater microstructural abnormalities of brain white matter tracts among OAB participants. These abnormalities occurred in the corpus callosum, bilateral anterior thalamic radiation and superior longitudinal fasciculus tracts, and bilateral insula and parahippocampal region. Among participants with OAB, higher OAB Questionnaire Short-Form scores were associated with decreased FA in the left inferior fronto-occipital fasciculus, P < .0001. DTI differences between OAB and controls were driven by the urinary urgency-only (OAB-dry) but not the UUI (OAB-wet) subgroup. CONCLUSIONS: Abnormalities in microstructural integrity in specific brain white matter tracts were more frequent in OAB patients. More severe OAB symptoms were correlated with greater degree of microstructural abnormalities in brain white matter tracts in patients with OAB. TRIAL REGISTRATION: ClinicalTrials.gov: NCT02485808.

Efficacy and Safety of Vibegron for Persistent Symptoms of Overactive Bladder in Men Being Pharmacologically Treated for Benign Prostatic Hyperplasia: Results From the Phase 3 Randomized Controlled COURAGE Trial.

PURPOSE: The efficacy and safety of vibegron, a ß3-adrenergic receptor agonist, was assessed among men with symptoms of overactive bladder (OAB) receiving pharmacologic treatment for benign prostatic hyperplasia (BPH) in a phase 3 randomized controlled trial. MATERIALS AND METHODS: Men ≥ 45 years with OAB symptoms and BPH, treated with α-blocker with/without 5α-reductase inhibitors, were randomized 1:1 to vibegron or placebo for 24 weeks. Coprimary end points were change from baseline at week 12 in mean daily micturitions and urgency episodes. Secondary end points were change from baseline at week 12 in mean nightly nocturia and daily urge urinary incontinence episodes, International Prostate Symptom Score‒storage score, and volume voided per micturition. Safety was evaluated via adverse events (AEs). RESULTS: Of 1105 participants randomized, 965 (87.3%) completed the trial. At week 12, vibegron was associated with significant reductions vs placebo in daily micturitions (least squares mean difference [95% CI], -0.74 [-1.02, -0.46]; P < .0001) and urgency episodes (-0.95 [-1.37, -0.54]; P < .0001). Vibegron was also associated with significant improvements vs placebo at week 12 in nocturia episodes (least squares mean difference, -0.22 [-0.36, -0.09]; P = .002), urge urinary incontinence episodes (-0.80 [-1.33, -0.27]; P = .003), International Prostate Symptom Score‒storage scores (-0.9 [-1.2, -0.6]; P < .0001), and volume voided (15.07 mL [9.13-21.02]; P < .0001). AE rates were similar in vibegron (45.0%) and placebo (39.0%) arms; AEs occurring in ≥ 2% of participants were hypertension (9.0% vs 8.3%), COVID-19 (4.0% vs 3.1%), UTI (2.5% vs 2.2%), and hematuria (2.0% vs 2.5%). CONCLUSIONS: In this trial, vibegron met all primary and secondary end points and was safe and well tolerated in men with OAB symptoms and pharmacologically treated BPH.

Naturalistic Bladder Filling Reveals Subtypes in Overactive Bladder Syndrome That Differentially Engages Urinary Urgency-Related Brain Circuits: Results From the Symptoms of Lower Urinary Tract Dysfunction Research Network (LURN).

PURPOSE: Overactive bladder (OAB) may be attributed to dysfunction in supraspinal brain circuits. Overactive bladder participants enrolled in the LURN (Symptoms of Lower Urinary Tract Dysfunction Research Network) study reported sensations of urinary urgency during a bladder-filling paradigm while undergoing brain functional MRI to map supraspinal dysfunction. MATERIALS AND METHODS: OAB participants and controls (CONs) completed 2 resting-state functional MRI scans following consumption of 350 mL water. Scans were conducted at fuller and emptier bladder states, interleaved with voiding. Urgency ratings (0-10) were assessed. Patterns of urgency during bladder filling were investigated using latent class trajectory models. Clusters of participants encompassing each pattern (ie, subtype) were derived from aggregated groups of OAB and CON independent of diagnosis. RESULTS: Two distinct patterns of urgency trajectories were revealed: first subtype with OAB and CON who were unresponsive to bladder filling (OAB-1 and CON-1) and second highly responsive subtype predominantly containing OAB (OAB-2). OAB-2 participants scored significantly higher on urinary symptoms but not pain or psychosocial measures. Neuroimaging analyses showed change in urgency due to both bladder filling and voided volume related to multiple loci of brain network connectivity in OAB-2, and in some cases, different than OAB-1 and/or CON-1. Sensorimotor to dorsomedial/dorsolateral prefrontal connectivity mediated the relationship between stimulus (voided volume) and percept (urgency) in OAB-2. CONCLUSIONS: Our results reveal different OAB subtypes with latent class trajectory models of urgency ratings during natural bladder filling. Functional MRI revealed differences in pathophysiology between subtypes, namely sensorimotor-prefrontal connectivity is a key locus in OAB patients with higher urinary symptoms.

Urothelium-derived prostanoids enhance contractility of urinary bladder smooth muscle and stimulate bladder afferent nerve activity in the mouse.

The transitional epithelial cells (urothelium) that line the lumen of the urinary bladder form a barrier between potentially harmful pathogens, toxins, and other bladder contents and the inner layers of the bladder wall. The urothelium, however, is not simply a passive barrier, as it can produce signaling factors, such as ATP, nitric oxide, prostaglandins, and other prostanoids, that can modulate bladder function. We investigated whether substances produced by the urothelium could directly modulate the contractility of the underlying urinary bladder smooth muscle. Force was measured in isolated strips of mouse urinary bladder with the urothelium intact or denuded. Bladder strips developed spontaneous tone and phasic contractions. In urothelium-intact strips, basal tone, as well as the frequency and amplitude of phasic contractions, were 25%, 32%, and 338% higher than in urothelium-denuded strips, respectively. Basal tone and phasic contractility in urothelium-intact bladder strips were abolished by the cyclooxygenase (COX) inhibitor indomethacin (10 µM) or the voltage-dependent Ca2+ channel blocker diltiazem (50 µM), whereas blocking neuronal sodium channels with tetrodotoxin (1 µM) had no effect. These results suggest that prostanoids produced in the urothelium enhance smooth muscle tone and phasic contractions by activating voltage-dependent Ca2+ channels in the underlying bladder smooth muscle. We went on to demonstrate that blocking COX inhibits the generation of transient pressure events in isolated pressurized bladders and greatly attenuates the afferent nerve activity during bladder filling, suggesting that urothelial prostanoids may also play a role in sensory nerve signaling.NEW & NOTEWORTHY This paper provides evidence for the role of urothelial-derived prostanoids in maintaining tone in the urinary bladder during bladder filling, not only underscoring the role of the urothelium as more than a barrier but also contributing to active regulation of the urinary bladder. Furthermore, cyclooxygenase products greatly augment sensory nerve activity generated by bladder afferents during bladder filling and thus may play a role in perception of bladder fullness.

Efficacy and safety of tibial nerve stimulation using a wearable device for overactive bladder.

OBJECTIVE: To evaluate the efficacy and safety of a wearable, smartphone-controlled, rechargeable transcutaneous tibial nerve stimulation (TTNS) device in patients with overactive bladder (OAB). PATIENTS AND METHODS: This multicentre, prospective, single-blind, randomised clinical trial included eligible patients with OAB symptoms who were randomly assigned to the stimulation group or sham group. The primary efficacy outcome was change from baseline in voiding frequency/24 h after 4 weeks of treatment. The secondary efficacy outcomes included changes in bladder diary outcomes (urgency score/void, nocturia episodes/day, micturition volume/void, and incontinence episodes/day), questionnaires on Overactive Bladder Symptom Score (OABSS), Patient Perception of Bladder Condition (PPBC), and American Urological Association Symptom Index Quality of Life Score (AUA-SI-QoL) at baseline and after 4 weeks of treatment. Device-related adverse events (AEs) were also evaluated. RESULTS: In the full analysis set (FAS), the mean (sd) change of voiding frequency/24 h in the stimulation group and sham group at 4 weeks were -3.5 (2.9) and -0.6 (2.4), respectively (P < 0.01). Similar results were obtained in the per-protocol set (PPS): -3.5 (2.9) vs -0.4 (2.3) (P < 0.01). In the FAS and PPS, micturition volume/void significantly improved at 4 weeks (P = 0.01 and P = 0.02). PPBC improvement almost reached significance in the FAS (P = 0.05), while it was significant in the PPS (P = 0.02). In the FAS and PPS, AUA-SI-QoL significantly improved at 4 weeks in the two groups (P < 0.01 and P < 0.01), whereas there were no significant differences in urgency score/void, nocturia episodes/day or OABSS between the groups. Also, no device-related serious AEs were reported. CONCLUSIONS: The non-invasive neuromodulation technique using the novel ambulatory TTNS device is effective and safe for treating OAB. Its convenience and easy maintenance make it a new potential home-based treatment modality. Future studies are warranted to confirm its longer-term efficacy.

Comparison of mirabegron and vibegron for clinical efficacy and safety in female patients with overactive bladder: a multicenter prospective randomized crossover trial.

PURPOSE: To compare the efficacy and safety of mirabegron and vibegron in female OAB patients. METHODS: We conducted a multicenter, prospective, randomized crossover study of female patients with OAB. The patients were assigned to Group MV (mirabegron for 8 weeks, followed by vibegron for 8 weeks) or group VM (vibegron for 8 weeks, followed by mirabegron for 8 weeks). The primary endpoint was the change in OABSS from baseline, and the secondary endpoint was the change in FVC parameters. After completion of the study, each patient was asked which drug was preferable. RESULTS: A total of 83 patients were enrolled (40 and 43 in groups MV and VM, respectively). At 8th and 16th week, 33 and 29 in Group MV and 34 and 27 in Group VM continued to receive the treatment. The change in PVR was not significantly different between treatment with mirabegron and vibegron. The changes in OABSS, nighttime frequency, mean, and maximum voided volume were similar between mirabegron and vibegron. The mean change in the daytime frequency was greater in the vibegron than in the mirabegron. Of the 56 patients, 15 (27%) and 30 (53%) preferred mirabegron and vibegron, respectively. The remaining 11 patients (20%) showed no preference. The change in the urgency incontinence score during vibegron was better in patients who preferred vibegron to mirabegron. CONCLUSION: The efficacies of mirabegron and vibegron in female patients was similar. The patients' preference for vibegron could depend on the efficacy of vibegron for urgency incontinence.

Efficacy of transcutaneous electrical nerve stimulation combined with mirabegron therapy compared with mirabegron monotherapy for overactive bladder: a prospective randomized controlled study.

PURPOSE: The objective was to evaluate the efficacy of transcutaneous electrical nerve stimulation (TENS) combined with mirabegron therapy compared with mirabegron monotherapy in the treatment of female patients with overactive bladder (OAB). METHODS: In this randomized controlled study, 100 female outpatients with OAB were screened. Among these patients, 86 who met the inclusion criteria were randomly divided into the TENS combined with mirabegron treatment group and mirabegron monotherapy treatment group, with 43 patients in each group. The voiding diary, Overactive Bladder Symptom Score (OABSS), Overactive Bladder Questionnaire Symptom Bother Score (OAB-q SBS), total health-related quality of life (OAB-q HRQoL), and treatment satisfaction-visual analog scale (TS-VAS) score before and after treatment were recorded to evaluate the efficacy of OAB treatment. Seventy-nine of the 86 patients (40 in the TENS plus mirabegron group and 39 in the mirabegron monotherapy group) completed 12 weeks of treatment. RESULTS: TENS combined with mirabegron therapy was superior to mirabegron monotherapy in improving the primary endpoints, including the daily number of micturition episodes and the daily MVV/micturition and secondary endpoints, including the daily number of urgency episodes, the OABSS, the OAB-q SBS, the HRQoL score and TS-VAS score. There were no statistically significant differences in urgency urinary incontinence and nocturia between the groups. Some minor adverse effects were observed, including muscle pain, local paresthesia and constipation. CONCLUSIONS: The combination of TENS and mirabegron was more effective than mirabegron alone in the treatment of female patients with OAB. TRIAL REGISTRATION NUMBER: ChiCTR2400080528 (31.01.2024, retrospectively registered).