Enhanced browning of adipose tissue by mirabegron-microspheres.

Thermogenic brown adipose tissue (BAT) has emerged as an attractive target for combating obesity. However, pharmacological activation of energy expenditure by BAT and/or induction of browning of white adipose tissue (WAT) has been hampered by cardiovascular side effects. To address these concerns, we developed polylactide-co-glycolide acid (PLGA) microspheres loaded with mirabegron (MIR), a selective beta-3 adrenergic receptor (ADRB3) agonist, to achieve sustained local induction and activation of thermogenic adipocytes. MIR-loaded PLGA microspheres (MIR-MS) effectively activated brown adipocytes and enhanced the thermogenic program in white adipocytes. Moreover, treating isolated inguinal WAT (iWAT) with MIR-MS resulted in increased expression of browning markers and elevated lipolysis mainly via ADRB3. In mice, injection of MIR-MS over four weeks induced browning of iWAT at the injection site. Importantly, local MIR-MS injection successfully mitigated unwanted cardiovascular risks, including high systolic blood pressure (SBP) and heart rate, as compared to MIR-treated mice. Finally, injecting MIR-MS into human subcutaneous WAT led to a significant induction of lipolysis and an increase in the expression of thermogenic marker uncoupling protein 1 (UCP1). Taken together, our findings indicate that MIR-MS function as a local drug release system that induces browning of human and murine subcutaneous WAT while mitigating undesirable cardiovascular effects.

Agonism of ß3-Adrenoceptors Inhibits Pathological Retinal Angiogenesis in the Model of Oxygen-Induced Retinopathy.

Purpose: In response to hypoxia, sympathetic fibers to the retina activate ß-adrenoceptors (ß-ARs) that play an important role in the regulation of vascular and neuronal functions. We investigated the role of ß3-AR using the mouse model of oxygen-induced retinopathy (OIR). Methods: Mouse pups were exposed to 75% oxygen at postnatal day 7 (PD7) followed by a return to room air at PD12. The ß3-AR preferential agonist BRL37344 was subcutaneously administered once daily at different times after the return to room air. At PD17, the OIR mice underwent flash and pattern electroretinogram. After sacrifice, retinal wholemounts were used for vessel staining or immunohistochemistry for astrocytes, Müller cells, or retinal ganglion cells (RGCs). In retinal homogenates, the levels of markers associated with neovascularization (NV), the blood-retinal barrier (BRB), or astrocytes were determined by western blot, and quantitative reverse-transcription polymerase chain reaction was used to assess ß3-AR messenger. Administration of the ß3-AR antagonist SR59230A was performed to verify BRL37344 selectivity. Results: ß3-AR expression is upregulated in response to hypoxia, but its increase is prevented by BRL37344, which counteracts NV by inhibiting the pro-angiogenic pathway, activating the anti-angiogenic pathway, recovering BRB-associated markers, triggering nitric oxide production, and favoring revascularization of the central retina through recovered density of astrocytes that ultimately counteracts NV in the midperiphery. Vasculature rescue prevents dysfunctional retinal activity and counteracts OIR-associated retinal ganglion cell loss. Conclusions: ß3-AR has emerged as a crucial intermediary in hypoxia-dependent NV, suggesting a role of ß3-AR agonists in the treatment of proliferative retinopathies.

Hyaluronan Mediates Cold-Induced Adipose Tissue Beiging.

Adipose tissue beiging refers to the process by which beige adipocytes emerge in classical white adipose tissue depots. Beige adipocytes dissipate chemical energy and secrete adipokines, such as classical brown adipocytes, to improve systemic metabolism, which is beneficial for people with obesity and metabolic diseases. Cold exposure and ß3-adrenergic receptor (AR) agonist treatment are two commonly used stimuli for increasing beige adipocytes in mice; however, their underlying biological processes are different. Transcriptional analysis of inguinal white adipose tissue (iWAT) has revealed that changes in extracellular matrix (ECM) pathway genes are specific to cold exposure. Hyaluronic acid (HA), a non-sulfated linear polysaccharide produced by nearly all cells, is one of the most common components of ECM. We found that cold exposure significantly increased iWAT HA levels, whereas the ß3-AR agonist CL316,243 did not. Increasing HA levels in iWAT by Has2 overexpression significantly increases cold-induced adipose tissue beiging; in contrast, decreasing HA by Spam1 overexpression, which encodes a hyaluronidase that digests HA, significantly decreases cold-induced iWAT beiging. All these data implicate a role of HA in promoting adipose tissue beiging, which is unique to cold exposure. Given the failure of ß3-AR agonists in clinical trials for obesity and metabolic diseases, increasing HA could serve as a new approach for recruiting more beige adipocytes to combat metabolic diseases.

Maintenance of thermogenic adipose tissues despite loss of the H3K27 acetyltransferases p300 or CBP.

Brown and beige adipose tissues are specialized for thermogenesis and are important for energy balance in mice. Mounting evidence suggests that chromatin-modifying enzymes are integral for the development, maintenance, and functioning of thermogenic adipocytes. p300 and cAMP-response element binding protein (CREB)-binding protein (CBP) are histone acetyltransferases (HATs) responsible for writing the transcriptionally activating mark H3K27ac. Despite their homology, p300 and CBP do have unique tissue- and context-dependent roles, which have yet to be examined in brown and beige adipocytes specifically. We assessed the requirement of p300 or CBP in thermogenic fat using uncoupling protein 1 (Ucp1)-Cre-mediated knockdown in mice to determine whether their loss impacted tissue development, susceptibility to diet-induced obesity, and response to pharmacological induction via ß3-agonism. Despite successful knockdown, brown adipose tissue mass and expression of thermogenic markers were unaffected by loss of either HAT. As such, knockout mice developed a comparable degree of diet-induced obesity and glucose intolerance to that of floxed controls. Furthermore, "browning" of white adipose tissue by the ß3-adrenergic agonist CL-316,243 remained largely intact in knockout mice. Although p300 and CBP have nonoverlapping roles in other tissues, our results indicate that they are individually dispensable within thermogenic fats specifically, possibly due to functional compensation by one another.NEW & NOTEWORTHY The role of transcriptionally activating H3K27ac epigenetic mark has yet to be examined in mouse thermogenic fats specifically, which we achieved here via Ucp1-Cre-driven knockdown of the histone acetyltransferases (HAT) p300 or CBP under several metabolic contexts. Despite successful knockdown of either HAT, brown adipose tissue was maintained at room temperature. As such, knockout mice were indistinguishable to controls when fed an obesogenic diet or when given a ß3-adrenergic receptor agonist to induce browning of white fat. Unlike other tissues, thermogenic fats are resilient to p300 or CBP ablation, likely due to sufficient functional overlap between them.

Kinin B1 receptor deficiency promotes enhanced adipose tissue thermogenic response to ß3-adrenergic stimulation.

OBJECTIVE AND DESIGN: Kinin B1 receptor (B1R) has a key role in adipocytes to protect against obesity and glycemic metabolism, thus becoming a potential target for regulation of energy metabolism and adipose tissue thermogenesis. MATERIAL OR SUBJECTS: Kinin B1 knockout mice (B1KO) were subjected to acute induction with CL 316,243 and chronic cold exposure. METHODS: Metabolic and histological analyses, gene and protein expression and RNA-seq were performed on interscapular brown adipose tissue (iBAT) and inguinal white adipose tissue (iWAT) of mice. RESULTS: B1KO mice, under acute effect of CL 316,243, exhibited increased energy expenditure and upregulated thermogenic genes in iWAT. They were also protected from chronic cold, showing enhanced non-shivering thermogenesis with increased iBAT mass (~ 90%) and recruitment of beige adipocytes in iWAT (~ 50%). Positive modulation of thermogenic and electron transport chain genes, reaching a 14.5-fold increase for Ucp1 in iWAT. RNA-seq revealed activation of the insulin signaling pathways for iBAT and oxidative phosphorylation, tricarboxylic acid cycle, and browning pathways for iWAT. CONCLUSION: B1R deficiency induced metabolic and gene expression alterations in adipose tissue, activating thermogenic pathways and increasing energy metabolism. B1R antagonists emerge as promising therapeutic targets for regulating obesity and associated metabolic disorders, such as inflammation and diabetes.

Advances in Outpatient Therapies and Treatment of Benign Prostatic Hyperplasia: A Comprehensive Review for Men's Health.

Benign prostate hyperplasia (BPH) affects a large number of men and can be treated with behavioral, medical, or surgical treatments. The newest addition to medical therapy is ß3-agonists for overactive lower urinary tract symptoms. Multiple new surgical treatments have become available in the past decade, including several clinic-based minimally invasive surgical techniques (eg, UroLift, Rezum, Optilume BPH), OR treatments (eg, Aquablation, single port robotics), and prostate artery embolization. The growth of options allows providers to better tailor BPH treatment to the specific disease factors and patient preferences.

Ligand-Receptor Interactions and Structure-Function Relationships in Off-Target Binding of the ß3-Adrenergic Agonist Mirabegron to α1A-Adrenergic Receptors.

The ß3-adrenoceptor agonist mirabegron is available for the treatment of storage symptoms of overactive bladder, including frequency, urgency, and incontinence. The off-target effects of mirabegron include binding to α1-adrenoceptors, which are central in the treatment of voiding symptoms. Here, we examined the structure-function relationships in the binding of mirabegron to a cryo-electron microscopy structure of α1A. The binding was simulated by docking mirabegron to a 3D structure of a human α1A-adrenoceptor (7YMH) using Autodock Vina. The simulations identified two binding states: slope orientation involving 10 positions and horizontal binding to the receptor surface involving 4 positions. No interactions occurred with positions constituting the α1A binding pocket, including Asp-106, Ser-188, or Phe-312, despite the positioning of the phenylethanolamine moiety in transmembrane regions close to the binding pocket by contact with Phe-288, -289, and Val-107. Contact with the unique positions of α1A included the transmembrane Met-292 during slope binding and exosite Phe-86 during horizontal binding. Exosite binding in slope orientation involved contact of the anilino part, rather than the aminothiazol end, to Ile-178, Ala-103, and Asn-179. In conclusion, contact with Met-292 and Phe-86, which are unique positions of α1A, accounts for mirabegron binding to α1A. Because of its lack of interactions with the binding pocket, mirabegron has lower affinity compared to α1A-blockers and no effects on voiding symptoms.

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).

Age-dependent decline of B3AR agonist-mediated activation of FAP UCP-1 expression in murine models of chronic rotator cuff repair.

Amibegron, a ß3-adrenergic receptor (B3AR) agonist, has recently been shown to provide therapeutic effects for chronic rotator cuff (RC) tears by inducing the expression of uncoupling protein 1 (UCP-1), a marker of brown fat, in fibroadipogenic progenitors (FAPs). However, it remains to be seen if these beneficial effects hold true with age and in older, more clinically relevant populations. This study seeks to understand the impacts of aging on the efficacy of amibegron to treat chronic RC tears. Young (4-month-old) and aged (33-month-old) C57BL/6 mice underwent a RC injury procedure with delayed repair (DR). Mice were equally randomized to receive amibegron or dimethyl sulfoxide (DMSO) treatments after repair. Functional ability was measured at baseline and 6-weeks after DR. Wet muscle weight and histology of injured and contralateral supraspinatus were also analyzed 6-weeks post-DR. For in vitro histology and real-time quantitative PCR experiments, FAPs were isolated from young and aged mice via fluorescence-activated cell sorting. Young and aged FAPs were treated with amibegron or DMSO either immediately after seeding (early exposure) or 8-days after seeding (late exposure). In vitro results showed that amibegron-mediated FAP UCP-1 expression decreases with age. In vivo data demonstrated that aged mice have a decreased responsiveness to amibegron and decreased propensity for intramuscular FAP UCP-1 expression. Further, delayed amibegron treatment with RC repair did not lead to improvements in muscle atrophy and functional outcomes. Our findings demonstrate that age and the timing of interventions play a critical role in FAP-targeted therapeutics for chronic injuries.

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.

Nerve Growth Factor and Brain-Derived Neurotrophic Factor as Potential Biomarkers of Mirabegron Efficacy in Patients with Overactive Bladder Syndrome.

INTRODUCTION: Overactive Bladder Syndrome (OAB) significantly impacts quality of life, necessitating improved diagnostic tools and treatment monitoring. This study explores the potential of neurotrophins, nerve growth factor (NGF), and brain-derived neurotrophic factor (BDNF) as urinary biomarkers in patients with OAB undergoing mirabegron therapy, a ß3-adrenergic agonist. This investigation is aimed at providing insights into the potential of neurotrophins to enhance OAB diagnosis and assess treatment efficacy. MATERIALS AND METHODS: Urinary NGF and BDNF levels were measured in 15 healthy controls and 30 patients with OAB. Patients were treated with mirabegron 50 mg once daily. Urinary NGF and BDNF levels were measured by enzyme-linked immunosorbent assay method and normalized by urinary creatinine levels (NGF/Cre and BDNF/Cre). The urinary NGF/Cre and BDNF/Cre levels were compared between controls and patients with OAB and subsequently at baseline and 3 months after mirabegron treatment. Treatment efficacy was assessed with the Indevus Urgency Severity Scale (IUSS) questionnaire. RESULTS: Urinary NGF/Cre and BDNF/Cre levels were significantly higher in patients with OAB than in the controls (p < 0.001 and p = 0.03 respectively). Moreover, NGF/Cre and BDNF/Cre levels significantly decreased post-mirabegron treatment (p < 0.001 and p = 0.005 respectively). Patients with improvement of OAB symptoms after treatment showed lower levels of NGF/Cre at the 3-month evaluation than those with no improvement (p = 0.05). CONCLUSION: Although both NGF/Cre and BDNF/Cre levels were significantly decreased after mirabegron treatment, only NGF/Cre levels were associated with treatment response.

Comparative analysis of real-world adherence and persistence patterns with vibegron, mirabegron, and anticholinergics in patients with overactive bladder: A retrospective claims study.

INTRODUCTION: Vibegron is a selective ß3-adrenergic receptor agonist that was approved by the US Food and Drug Administration in December 2020 for the treatment of overactive bladder in adults. This retrospective study assessed US pharmacy claims data to evaluate the real-world adherence and persistence of vibegron compared with mirabegron and with anticholinergics. MATERIALS AND METHODS: This analysis used the Optum Research Database to identify adults with ≥1 pharmacy claim for vibegron, mirabegron, or an anticholinergic from April 1, 2021, to August 31, 2022. Patients had ≥ 90 days of continuous commercial or Medicare medical and pharmacy coverage preindex and ≥ 60 days of continuous pharmacy coverage postindex. Two independent propensity-score models matched patients treated with (1) vibegron versus mirabegron and (2) vibegron versus anticholinergics on key variables such as demographics and clinical characteristics, index copay, days' supply, and time of entry into analysis (index quarter). Adherence was measured by proportion of days covered (PDC) from index to the end of follow-up and was defined as PDC ≥ 80%. Persistence was defined as days to discontinuation of index medication (first 30-day gap) or end of follow-up. RESULTS: The matched vibegron and mirabegron cohorts included 4921 and 9842 patients, respectively, and the matched vibegron and anticholinergic cohorts included 4676 and 9352 patients, respectively. Patients receiving vibegron had greater mean PDC versus patients receiving mirabegron (0.67 vs. 0.64, respectively; p < 0.001) or anticholinergics (0.67 vs. 0.58; p < 0.001). A greater percentage of patients receiving vibegron were adherent versus those receiving mirabegron (49.0% vs. 45.1%, respectively; p < 0.001) or anticholinergics (49.1% vs. 38.5%; p < 0.001). Persistence was longer with vibegron compared with both mirabegron (median [95% CI], 171 [159-182] vs. 128 [122-137] days, respectively; p < 0.001) and anticholinergics (172 [159-183] vs. 91 [91] days; p < 0.001). CONCLUSION: In this retrospective analysis of pharmacy claims data, patients receiving vibegron exhibited significantly higher adherence and demonstrated longer persistence in comparison to matched patient cohorts receiving either mirabegron or anticholinergics.

The impact of pharmacotherapy on sexual function in female patients being treated for idiopathic overactive bladder: a systematic review.

BACKGROUND: Overactive bladder (OAB) is a condition defined by urgency with or without incontinence which disproportionately affects female patients and has a negative impact on sexual enjoyment and avoidance behaviour. Pharmacotherapy can be considered one of the main options for treating OAB. This research set out to determine the impact of pharmacotherapy on sexual function in females with OAB. METHODS: This research used the robust methodology of a systematic review. The clinical question was formulated using the PICO (population, intervention, control, and outcomes) format to include females being treated with pharmacotherapy (anticholinergics or beta-3 adrenergic agonists) for idiopathic OAB with the use of a validated questionnaire assessing self-reported sexual function at baseline and post-treatment. The review incorporated the MEDLINE, PubMed and EMBASE databases. The AMSTAR 2 (A Measurement Tool to Assess Systematic Reviews) appraisal tool was used to guide the review process. Two reviewers worked independently in screening abstracts, deciding on the inclusion of full-texts, data extraction and risk of bias assessment. RESULTS: In female patients with OAB, pharmacotherapy does seem to offer at least partial improvement in self-reported sexual function outcomes after 12 weeks of therapy. Still, the value of this finding is limited by an overall poor quality of evidence. Patients with a higher degree of bother at baseline stand to benefit the most from treatment when an improvement within this health-related quality of life domain is sought. CONCLUSION: This research should form the basis for a well-conducted randomized controlled study to accurately assess sexual function improvements in females being treated with pharmacotherapy for OAB.

Safety and efficacy of beta-3 adrenergic agonists in treating neurogenic lower urinary tract dysfunction: A systematic review and meta-analysis.

PURPOSE: To evaluate efficacy and safety of beta-3 adrenergic agonists in adults with neurogenic lower urinary tract dysfunction. MATERIALS AND METHODS: According to a protocol (CRD42022350079), we searched multiple data sources for published and unpublished randomized controlled trials (RCTs) up to 2nd August 2022. Two review authors independently screened studies and abstracted data from the included studies. We performed statistical analyses by using a random-effects model and interpreted them according to the Cochrane Handbook for Systematic Reviews of Interventions. We used GRADE guidance to rate the certainty of evidence (CoE). RESULTS: We found data to inform two comparisons: beta-3 adrenergic agonists versus placebo (4 RCTs) and anticholinergics (2 RCTs). Only mirabegron was used for intervention in all included studies. Compared to placebo, beta-3 adrenergic agonists may have a clinically unimportant effect on urinary symptoms score (mean difference [MD] -2.50, 95% confidence interval [CI] -4.78 to -0.22; I²=92%; 2 RCTs; 192 participants; low CoE) based on minimal clinically important difference of 3. We are very uncertain of the effects of beta-3 adrenergic agonists on quality of life (MD 10.86, 95% CI 1.21 to 20.50; I²=41%; 2 RCTs; 98 participants; very low CoE). Beta-3 adrenergic agonists may result in little to no difference in major adverse events (cardiovascular adverse events) (risk ratio 0.57, 95% CI 0.14 to 2.37; I²=0%; 4 RCTs; 310 participants; low CoE). Compared to anticholinergics, no study reported urinary symptom scores and quality of life. There were no major adverse events (cardiovascular adverse events) in either study group (1 study; 60 participants; very low CoE). CONCLUSIONS: Compared to placebo, beta-3 adrenergic agonists may have similar effects on urinary symptom scores and major adverse events. There were uncertainties about their effects on quality of life. Compared to anticholinergics, we are either very uncertain or have no evidence about urinary symptom scores, quality of life, and major adverse events.

ENDOGENOUS ß 3 -ADRENERGIC RECEPTOR ACTIVATION ALLEVIATES SEPSIS-INDUCED CARDIOMYOCYTE APOPTOSIS VIA PI3K/AKT SIGNALING PATHWAY.

ABSTRACT: ß 3 -adrenergic receptor (ß 3 -AR) has been proposed as a new therapy for several myocardial diseases. However, the effect of ß 3 -AR activation on sepsis-induced myocardial apoptosis is unclear. Here, we investigated the effect of ß 3 -AR activation on the cardiomyocyte apoptosis and cardiac dysfunction in cecal ligation and puncture (CLP)-operated rats and lipopolysaccharide (LPS)-treated cardiomyocytes. We found that ß 3 -AR existed both in adult rat ventricular myocytes (ARVMs) and H9c2 cells. The expression of ß 3 -AR was upregulated in LPS-treated ARVMs and the heart of CLP rats. Pretreatment with ß 3 -AR agonist, BRL37344, inhibited LPS-induced cardiomyocyte apoptosis and caspase-3, -8, and -9 activation in ARVMs. BRL37344 also reduced apoptosis and increased the protein levels of PI3K, p-Akt Ser473 and p-eNOS Ser1177 in LPS-treated H9c2 cells. Inhibition of PI3K using LY294002 abolished the inhibitory effect of BRL37344 on LPS-induced caspase-3, -8, and -9 activation in H9c2 cells. Furthermore, administration of ß 3 -AR antagonist, SR59230A (5 mg/kg), significantly decreased the maximum rate of left ventricular pressure rise (+dP/dt) in CLP-induced septic rats. SR59230A not only increased myocardial apoptosis, reduced p-Akt Ser473 and Bcl-2 contents, but also increased mitochondrial Bax, cytoplasm cytochrome c, cleaved caspase-9, and cleaved caspase-3 levels of the myocardium in septic rats. These results suggest that endogenous ß 3 -AR activation alleviates sepsis-induced cardiomyocyte apoptosis via PI3K/Akt signaling pathway and maintains intrinsic myocardial systolic function in sepsis.

In vitro effects of ß3-adrenoceptor agonist mirabegron on the human ureter.

INTRODUCTION: This study aimed to investigate the effect of mirabegron, a ß3-adrenoceptor agonist with widespread clinical use for treating overactive bladder disease, on isolated healthy human ureter strips. MATERIALS AND METHODS: This was a prospective study employing a series of in vitro organ bath experiments using ureteral tissues of kidney grafts from 10 healthy donors. The ureteral strips were subjected to cumulative mirabegron concentrations (10-9-10-4.5 M). Effects on frequency or amplitude of spontaneous, 10 mM KCl- or EFS-induced contractions were evaluated. RESULTS: Mirabegron decreased the frequency of spontaneous ureteric contraction in a concentration-dependent manner. Statistically significant decrease in the frequency of spontaneous contraction was observed at 10-8-10-4.5 M. In 10 mM KCl medium, statistically significant change in frequency was observed at 10-9-10-4.5 M. Statistically significant decrease in the amplitudes of spontaneous contraction was observed at 10-7-10-4.5 M. In a 10 mM KCl medium, statistically significant change in amplitudes was observed at 10-8-10-4.5 M. CONCLUSIONS: Mirabegron reduced the amplitude and frequency of human ureter activity in in vitro organ bath studies. This effect was achieved in a dose-dependent manner on isolated tissue strips. Although monotherapy with mirabegron remains uncertain, this study has the potential to elucidate the mechanism underlying the effectiveness of mirabegron, particularly in combination therapy for ureteral stones.

Role of cAMP/pCREB and GSK-3ß/NF-κB p65 signaling pathways in the renoprotective effect of mirabegron against renal ischemia-reperfusion injury in rats.

Acute kidney injury and other renal disorders are thought to be primarily caused by renal ischemia-reperfusion (RIR). Cyclic adenosine monophosphate (cAMP) has plenty of physiological pleiotropic effects and preserves tissue integrity and functions. This research aimed to examine the potential protective effects of the ß3-adrenergic receptors agonist mirabegron in a rat model of RIR and its underlying mechanisms. Male rats enrolled in this work were given an oral dose of 30 mg/kg mirabegron for two days before surgical induction of RIR. Renal levels of kidney injury molecule-1 (KIM-1), monocyte chemoattractant protein-1 (MCP-1), tumor necrosis factor-alpha (TNF-α), Interleukin-10 (IL-10), cAMP, cAMP-responsive element binding protein (pCREB), and glycogen synthase kinase-3 beta (GSK-3ß) were assessed along with blood urea nitrogen and serum creatinine. Additionally, caspase-3 and nuclear factor-kappa B (NF-κB) p65 were explored by immunohistochemical analysis. Renal specimens were inspected for histopathological changes. RIR led to renal tissue damage with elevated blood urea nitrogen and serum creatinine levels. The renal KIM-1, MCP-1, TNF-α, and GSK-3ß were significantly increased, while IL-10, cAMP, and pCREB levels were reduced. Moreover, upregulation of caspase-3 and NF-κB p65 protein expression was seen in RIR rats. Mirabegron significantly reduced kidney dysfunction, histological abnormalities, inflammation, and apoptosis in the rat renal tissues. Mechanistically, mirabegron mediated these effects via modulation of cAMP/pCREB and GSK-3ß/NF-κB p65 signaling pathways. Mirabegron administration could protect renal tissue and maintain renal function against RIR.

The ß3-AR agonist BRL37344 ameliorates the main symptoms of X-linked nephrogenic diabetes insipidus in the mouse model of the disease.

X-linked nephrogenic diabetes insipidus (X-NDI) is a rare congenital disease caused by inactivating mutations of the vasopressin type-2 receptor (AVPR2), characterized by impaired renal concentrating ability, dramatic polyuria, polydipsia and risk of dehydration. The disease, which still lacks a cure, could benefit from the pharmacologic stimulation of other GPCRs, activating the cAMP-intracellular pathway in the kidney cells expressing the AVPR2. On the basis of our previous studies, we here hypothesized that the ß3-adrenergic receptor could be such an ideal candidate. We evaluated the effect of continuous 24 h stimulation of the ß3-AR with the agonist BRL37344 and assessed the effects on urine output, urine osmolarity, water intake and the abundance and activation of the key renal water and electrolyte transporters, in the mouse model of X-NDI. Here we demonstrate that the ß3-AR agonism exhibits a potent antidiuretic effect. The strong improvement in symptoms of X-NDI produced by a single i.p. injection of BRL37344 (1 mg/kg) was limited to 3 h but repeated administrations in the 24 h, mimicking the effect of a slow-release preparation, promoted a sustained antidiuretic effect, reducing the 24 h urine output by 27%, increasing urine osmolarity by 25% and reducing the water intake by 20%. At the molecular level, we show that BRL37344 acted by increasing the phosphorylation of NKCC2, NCC and AQP2 in the renal cell membrane, thereby increasing electrolytes and water reabsorption in the kidney tubule of X-NDI mice. Taken together, these data suggest that human ß3-AR agonists might represent an effective possible treatment strategy for X-NDI.

First-In-Man Trial of ß3-Adrenoceptor Agonist Treatment in Chronic Heart Failure: Impact on Diastolic Function.

ABSTRACT: Diastolic dysfunction (DD) in heart failure is associated with increased myocardial cytosolic calcium and calcium-efflux through the sodium-calcium exchanger depends on the sodium gradient. Beta-3-adrenoceptor (ß3-AR) agonists lower cytosolic sodium and have reversed organ congestion. Accordingly, ß3-AR agonists might improve diastolic function, which we aimed to assess. In a first-in-man, randomized, double-blinded trial, we assigned 70 patients with HF with reduced ejection fraction, New York Heart Association II-III, and left ventricular ejection fraction <40% to receive the ß3-AR agonist mirabegron (300 mg/day) or placebo for 6 months, in addition to recommended heart failure therapy. We performed echocardiography and cardiac computed tomography and measured N-terminal probrain natriuretic peptide at baseline and follow-up. DD was graded per multiple renowned algorithms. Baseline and follow-up data were available in 57 patients (59 ± 11 years, 88% male, 49% ischemic heart disease). No clinically significant changes in diastolic measurements were found within or between the groups by echocardiography (E/e' placebo: 13 ± 7 to 13 ± 5, P = 0.21 vs. mirabegron: 12 ± 6 to 13 ± 8, P = 0.74, between-group follow-up difference 0.2 [95% CI, -3 to 4], P = 0.89) or cardiac computed tomography (left atrial volume index: between-group follow-up difference 9 mL/m 2 [95% CI, -3 to 19], P = 0.15). DD gradings did not change within or between the groups following 2 algorithms ( P = 0.72, P = 0.75). N-terminal probrain natriuretic peptide remained unchanged in both the groups ( P = 0.74, P = 0.64). In patients with HF with reduced ejection fraction, no changes were identified in diastolic measurements, gradings or biomarker after ß3-AR stimulation compared with placebo. The findings add to the previous literature questioning the role of impaired Na + -Ca 2+ -mediated calcium export as a major culprit in DD. NCT01876433.