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.

Role of transient receptor potential ankyrin 1 in idiopathic pulmonary fibrosis: modulation of M2 macrophage polarization.

Idiopathic pulmonary fibrosis (IPF) poses significant challenges due to limited treatment options despite its complex pathogenesis involving cellular and molecular mechanisms. This study investigated the role of transient receptor potential ankyrin 1 (TRPA1) channels in regulating M2 macrophage polarization in IPF progression, potentially offering novel therapeutic targets. Using a bleomycin-induced pulmonary fibrosis model in C57BL/6J mice, we assessed the therapeutic potential of the TRPA1 inhibitor HC-030031. TRPA1 upregulation was observed in fibrotic lungs, correlating with worsened lung function and reduced survival. TRPA1 inhibition mitigated fibrosis severity, evidenced by decreased collagen deposition and restored lung tissue stiffness. Furthermore, TRPA1 blockade reversed aberrant M2 macrophage polarization induced by bleomycin, associated with reduced Smad2 phosphorylation in the TGF-ß1-Smad2 pathway. In vitro studies with THP-1 cells treated with bleomycin and HC-030031 corroborated these findings, highlighting TRPA1's involvement in fibrotic modulation and macrophage polarization control. Overall, targeting TRPA1 channels presents promising therapeutic potential in managing pulmonary fibrosis by reducing pro-fibrotic marker expression, inhibiting M2 macrophage polarization, and diminishing collagen deposition. This study sheds light on a novel avenue for therapeutic intervention in IPF, addressing a critical need in the management of this challenging disease.

Methylglyoxal activates transient receptor potential A1/V1 via reactive oxygen species in the spinal dorsal horn.

Methylglyoxal (MGO), a highly reactive dicarbonyl metabolite of glucose primarily formed during the glycolytic pathway, is a precursor of advanced glycation end-products (AGEs). Recently, numerous studies have shown that MGO accumulation can cause pain and hyperalgesia. However, the mechanism through which MGO induces pain in the spinal dorsal horn remains unclear. The present study investigated the effect of MGO on spontaneous excitatory postsynaptic currents (sEPSC) in rat spinal dorsal horn neurons using blind whole-cell patch-clamp recording. Perfusion of MGO increased the frequency and amplitude of sEPSC in spinal horn neurons in a concentration-dependent manner. Additionally, MGO administration increased the number of miniature EPSC (mEPSC) in the presence of tetrodotoxin, a sodium channel blocker. However, 6-cyano-7-nitroqiunocaline-2,3-dione (CNQX), an AMPA/kainate receptor antagonist, blocked the enhancement of sEPSC by MGO. HC-030031, a TRP ankyrin-1 (TRPA1) antagonist, and capsazepine, a TRP vanilloid-1 (TRPV1) antagonist, inhibited the action of MGO. Notably, the effects of MGO were completely inhibited by HC-030031 and capsazepine. MGO generates reactive oxygen species (ROS) via AGEs. ROS also potentially induce pain via TRPA1 and TRPV1 in the spinal dorsal horn. Furthermore, we examined the effect of MGO in the presence of N-tert-butyl-α-phenylnitrone (PBN), a non-selective ROS scavenger, and found that the effect of MGO was completely inhibited. These results suggest that MGO increases spontaneous glutamate release from the presynaptic terminal to spinal dorsal horn neurons through TRPA1, TRPV1, and ROS and could enhance excitatory synaptic transmission.

Stimulatory effect of methylglyoxal on capsaicin-sensitive lung vagal afferents in rats: role of TRPA1.

Methylglyoxal (MG), a reactive metabolic byproduct of glycolysis, is a causative of painful diabetic neuropathy. Patients with diabetes are associated with more frequent severe asthma exacerbation. Stimulation of capsaicin-sensitive lung vagal (CSLV) afferents may contribute to the pathogenesis of hyperreactive airway diseases such as asthma. However, the possibility of the stimulatory effect of MG on CSLV afferents and the underlying mechanisms remain unknown. Our results showed that intravenous injection of MG (25 mg/kg, MG25) in anesthetized, spontaneously breathing rats elicited pulmonary chemoreflexes characterized by apnea, bradycardia, and hypotension. The MG-induced apneic response was reproducible and dose dependent. MG25 no longer evoked these reflex responses after perineural capsaicin treatment of both cervical vagi to block C-fibers' conduction, suggesting that the reflexes were mediated through the stimulation of CSLV afferents. Pretreatment with HC030031 [an antagonist of transient receptor potential ankyrin subtype 1 protein (TRPA1)] or AP18 (another TRPA1 antagonist), but not their vehicle, markedly attenuated the apneic response induced by MG25. Consistently, electrophysiological results showed that pretreatment with HC030031 largely attenuated the intense discharge in CSLV afferents induced by injection of MG25 in open-chest and artificially ventilated rats. In isolated CSLV neurons, the perfusion of MG evoked an abrupt and pronounced increase in calcium transients in a concentration-dependent manner. This stimulatory effect on CSLV neurons was also abolished by HC030031 treatment but not by its vehicle. In conclusion, these results suggest that MG exerts a stimulatory effect on CSLV afferents, inducing pulmonary chemoreflexes, and such stimulation is mediated through the TRPA1 activation.NEW & NOTEWORTHY Methylglyoxal (MG) is implicated in the development of painful diabetic neuropathy. A retrospective cohort study revealed an increased incidence of asthma exacerbations in patients with diabetes. This study demonstrated that elevated circulating MG levels stimulate capsaicin-sensitive lung vagal afferents via activation of TRPA1, which in turn triggers respiratory reflexes. These findings provide new information for understanding the pathogenic mechanism of diabetes-associated hyperreactive airway diseases and potential therapy.

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).

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.

An individual participant meta-analysis of mirabegron in multiple sclerosis and spinal cord injury.

INTRODUCTION: Our objective was to conduct an individual patient data meta-analysis (IPDMA) of the two published randomized placebo-controlled trials of mirabegron in people with neurogenic lower urinary tract dysfunction (NLUTD) due to spinal cord injury (SCI) or multiple sclerosis (MS). METHODS: We identified two randomized, placebo-controlled trials. We extracted individual patient data from the trials and evaluated two primary outcomes: change in maximum cystometric capacity and change in the patient perception of bladder condition (PPBC). We also evaluated several secondary outcomes related to urodynamic function and quality of life. We conducted three exploratory analyses to test hypotheses based on our clinical experiences with mirabegron in NLUTD. Analysis of covariance with adjustment for baseline values was used for the statistical analysis. RESULTS: Our IPDMA included 98 patients from the two trials. The results showed that mirabegron was associated with a significant improvement in maximum cystometric capacity (+41 mL, p = 0.04) and in the PPBC (-0.8, p < 0.01) compared to placebo. Secondary outcomes including peak neurogenic detrusor overactivity pressure (-20 cm H2O, p < 0.01), incontinence-QOL score (+12, p < 0.01), and 24 h pad weights (-79 g, p = 0.04) also improved significantly compared to placebo. Exploratory analyses found similar improvements in people with MS and SCI; some outcomes improved to a greater degree among people with incomplete SCI, or SCIs that were below T7. CONCLUSIONS: Our IPDMA provides evidence supporting the use of mirabegron in patients with NLUTD due to SCI or MS. Further work evaluating differential responses in people with different SCI lesion characteristics may be warranted.

Safety and efficacy of an α1 -blocker plus mirabegron compared with an α1 -blocker plus antimuscarinic in men with lower urinary tract symptoms secondary to benign prostatic hyperplasia and overactive bladder: A systematic review and network meta-analysis.

AIM: Antimuscarinics and the ß3-adrenoreceptor agonist, mirabegron, are commonly used for treating patients with overactive bladder (OAB) and α1 -adrenoreceptor antagonists (α1 -blockers) are the main pharmacological agents used for treating lower urinary tract symptoms (LUTS) secondary to benign prostatic hyperplasia (BPH). As these conditions commonly occur together, the aim of this systematic review was to identify publications that compared the use of an α1 -blocker plus mirabegron with an α1 -blocker plus antimuscarinic in men with LUTS secondary to BPH and OAB. A meta-analysis was subsequently conducted to explore the safety and efficacy of these combinations. METHODS: Included records had to be from a parallel-group, randomized clinical trial that was ≥8 weeks in duration. Participants were male with LUTS secondary to BPH and OAB. The indirect analyses that were identified compared an α1 -blocker plus OAB agent with an α1 -blocker plus placebo. The PubMed/Medical Literature Analysis and Retrieval System Online, the Excerpta Medica Database, the Cochrane Central Register of Controlled Trials, and the ClinicalTrials.gov registry were searched for relevant records up until March 5, 2020. Safety outcomes included incidences of overall treatment-emergent adverse events (TEAEs) and urinary retention, postvoid residual volume, and maximum urinary flow (Qmax ). Primary efficacy outcomes were micturitions/day, incontinence episodes/day, and urgency episodes/day, and secondary outcomes were Overactive Bladder Symptom Score and International Prostate Symptom Score. A Bayesian network meta-analysis approach was used for the meta-analysis. RESULTS: Out of a total of 1039 records identified, 24 were eligible for inclusion in the meta-analysis. There were no statistically significant differences between the α1 -blocker plus mirabegron and α1 -blocker plus antimuscarinic groups in terms of the comparisons identified for all the safety and efficacy analyses conducted. Numerically superior results were frequently observed for the α1 -blocker plus mirabegron group compared with the α1 -blocker plus antimuscarinic group for the safety parameters, including TEAEs, urinary retention, and Qmax . For some of the efficacy parameters, most notably micturitions/day, numerically superior results were noted for the α1 -blocker plus antimuscarinic group. Inconsistency in reporting and study variability were noted in the included records, which hindered data interpretation. CONCLUSION: This systematic review and meta-analysis showed that an α1 -blocker plus mirabegron and an α1 -blocker plus antimuscarinic have similar safety and efficacy profiles in male patients with LUTS secondary to BPH and OAB. Patients may, therefore, benefit from the use of either combination within the clinical setting.

Effects of mirabegron on brown adipose tissue and metabolism in humans: A systematic review and meta-analysis.

BACKGROUND: Brown adipose tissue (BAT) has emerged as a potential therapeutic target for metabolic disorders due to its thermogenic and anti-obesity properties. ß3-adrenergic receptor (ß3-AR) agonists have also gained attention as potential agents for BAT activation and metabolic regulation. Mirabegron, a selective ß3-AR-agonist used clinically for overactive bladder syndrome, has been explored for its utility in metabolic disorders. However, the controversy surrounding the ability of mirabegron to activate BAT to accelerate metabolism requires further investigation. The aim of this systematic review is to characterize comprehensively the impact of mirabegron on human BAT and its metabolism. METHODS: We searched PubMed Central, Web of Science, Embase, and Cochrane Library databases for relevant papers published from the date of database inception to March 2023 for systematic reviews and meta-analyses. We extracted data on primary outcome indicators such as BAT volume, BAT activity, body temperature, and resting energy expenditure (REE), as well as secondary outcome indicators such as heart rate (HR), diastolic blood pressure (DBP), systolic blood pressure (SBP), non-esterified fatty acids (NEFA), blood glucose, and blood insulin from relevant studies. For studies that did not provide suitable data for meta-analysis, we used narrative data synthesis. For studies that provided suitable data for meta-analysis, we conducted meta-analysis using RevMan 5.4 software. RESULTS: We reviewed 10 papers and included 6 in our meta-analysis. Our findings revealed no significant changes in BAT volume (p = 0.72) or blood glucose (p = 0.52) with mirabegron when compared to the placebo or pre-dose population. However, patients showed significant increases in BAT activity (p < 0.01), blood NEFA (p < 0.01), body temperature (p < 0.01), REE (p < 0.01), HR (p < 0.01), DBP (p < 0.01), SBP (p = 0.25), and blood insulin (p < 0.01). CONCLUSION: Through our meta-analysis of 6 papers, we found that mirabegron has the potential to increase human BAT activity, REE, NEFA content, body temperature, HR, blood pressure, and blood insulin content. These effects may lead to reductions in blood glucose levels in obese/overweight and diabetic patients. Additionally, the activation of BAT by mirabegron could represent a novel approach for treating obesity, diabetes, and cardiovascular disease. TRIAL REGISTRATION NUMBER AND DATE: CRD42023413446, 04/11/2023.

Lessons learned from a multi-data source research collaboration: The mirabegron post-authorization safety study program.

BACKGROUND: Many factors contribute to developing and conducting a successful multi-data source, non-interventional, post-authorization safety study (NI-PASS) for submission to multiple health authorities. Such studies are often large undertakings; evaluating and sharing lessons learned can provide useful insights to others considering similar studies. OBJECTIVES: We discuss challenges and key methodological and organizational factors that led to the delivery of a successful post-marketing requirement (PMR)/PASS program investigating the risk of cardiovascular and cancer events among users of mirabegron, an oral medication for the treatment of overactive bladder. RESULTS: We provide context and share learnings, including sections on research program collaboration, scientific transparency, organizational approach, mitigation of uncertainty around potential delays, validity of study outcomes, selection of data sources and optimizing patient numbers, choice of comparator groups and enhancing precision of estimates of associations, potential confounding and generalizability of study findings, and interpretation of results. CONCLUSIONS: This large PMR/PASS program was a long-term commitment from all parties and benefited from an effective coordinating center and extensive scientific interactions across research partners, scientific advisory board, study sponsor, and health authorities, and delivered useful learnings related to the design and organization of multi-data source NI-PASS.

Evaluation of acetanilide and antipyrine adsorption on lignin-derived activated carbons.

In this study, the removal of two emerging pollutants (EPs), antipyrine and acetanilide, through adsorption on activated carbons (ACs) prepared by chemical activation of Organosolv lignin with H3PO4 were evaluated. ACs with different pore size distribution were obtained at different impregnation ratios (H3PO4/lignin, 0.5-3.0 w/w) and activating temperatures (500-900 °C). The porosity and surface chemistry of the ACs were determined, and a bimodal size distribution of micropores and narrow mesopores was observed for the different ACs. These ACs were tested for antipyrine and acetanilide adsorption in aqueous solutions in a batch system at 20 °C and low concentration levels (0.5-10 ppm). In general, the ACs exhibited higher adsorption affinity to acetanilide than to antipyrine due to its smaller molecular size. Langmuir adsorption isotherm was able to describe the adsorption equilibrium data. A new Linear Driving Force (2-LDF) kinetic model, based on the bimodal size distribution of micropores and narrow mesopores observed for the ACs has been developed. The new model provided a more accurate description of the batch adsorption rates than that obtained from conventional kinetic models, and also enabled to relate the pore size distribution of the adsorbent with the adsorption kinetics. The validity of this model was checked in small-scale column fixed bed adsorption for the AC showing the highest affinity for both EP. The kinetic model and equilibrium adsorption isotherm obtained from the batch experiments were successfully used to provide an accurate description of the bed service time and the full breakthrough profile of acetanilide and antipyrine.

Ultimate fate, transformation, and toxicological consequences of herbicide pretilachlor to biotic components and associated environment: An overview.

Herbicides are applied for effective weed management in order to increase the crop yield. In recent decades, the overuse of these chemicals has posed adverse effects on different biotic components of the environment. Pretilachlor has been widely used during last few decades for weed management in paddy crop. Its excessive use may prove fatal for environment, various organisms, and nontarget plants. Thus, it is pertinent to know the extent to which herbicide residues remain in environment. The potential mobility and the release rate of herbicide in the soil are important factors governing ecotoxicological impact and degradation rate. Therefore, several techniques are being investigated for its effective removal from the contaminated sites. Furthermore, efforts have also been made to study the degradation of pretilachlor by various physicochemical processes, resulting into the formation of different types of metabolites. This review summarizes the available information on environmental fate, various degradation processes, microbial biotransformation, metabolites formed, ecotoxicological effects, techniques for detection in environmental samples, effect of safener, and various control release formulations for sustained release of pretilachlor in applied fields. The information so obtained will be very advantageous in deciding the future policies for safe and judicious use of the herbicide by maintaining health and environmental sustainability.

Mirabegron Add-On Tamsulosin for Men with Overactive Bladder Symptoms: A Pooled Analysis of Four Randomized Controlled Trials.

INTRODUCTION: Overactive bladder symptoms (OABSs) affect patients' quality of life (QOL) worldwide. This pooled analysis compared the efficacy and safety of mirabegron add-on tamsulosin with those of tamsulosin add-on placebo in OABS treatment. METHODS: PubMed, Embase, MEDLINE, and the Cochrane Controlled Trial Register databases were searched for randomized controlled trials (RCTs) examining the efficacy of mirabegron add-on therapy to tamsulosin in the treatment of OABS. Moreover, references from the selected studies were screened. Review Manager 5.4 was used to analyze data. RESULTS: Four RCTs involving 1,397 patients with OABS were selected. Of the total, 697 patients receiving mirabegron add-on tamsulosin constituted the experimental group, and 700 patients receiving tamsulosin add-on placebo constituted the control group. The efficacy endpoints were as follows: mean number of micturition per day (mean difference [MD] = -0.26, 95% confidence interval [CI] = -0.41 to -0.10, p = 0.0001), urgency episodes per day (MD = -0.67, 95% CI = -1.02 to -0.32, p = 0.0002), urgency urinary incontinence (UUI) episodes per day (MD = -0.42, 95% CI = -0.66 to -0.19, p = 0.0005), mean volume voided/micturition (MD = 10.84, 95% CI = 4.97-16.71, p = 0.0003), total International Prostate Symptom Score (IPSS) (MD = -2.01, 95% CI = -4.02 to -0.01, p = 0.05), and IPSS QOL index (MD = -0.65, 95% CI = -0.94 to -0.35, p < 0.0001). Mirabegron therapy, an add-on therapy to tamsulosin, was effective in treating patients with OABS. Moreover, mirabegron might reduce the total IPSS (MD = -2.01, 95% CI = -4.02 to -0.01, p = 0.05). The safety endpoint, treatment-emergent adverse events (odds ratio = 0.94, 95% CI = 0.78-1.13, p = 0.49), suggested that although mirabegron was well-tolerated, it possibly increased the post-void residual urine volume (MD = 10.28, 95% CI = 1.82-18.75, p = 0.02). CONCLUSION: Combination therapy using mirabegron and tamsulosin may be effective in treating patients with non-neurogenic OABS in terms of UUI episodes, total IPSS, and IPSS QOL index. However, its effectiveness must be verified by analyzing additional factors for OABS through further RCTs.

Evaluation of antifungal activity, mechanisms of action and toxicological profile of the synthetic amide 2-chloro-N-phenylacetamide.

Aspergillus niger causes infections such as otitis and pulmonary aspergillosis in immunocompromised individuals. Treatment involves voriconazole or amphotericin B, and due to the increase in fungal resistance, the search for new compounds with antifungal activity has intensified. In the development of new drugs, cytotoxicity and genotoxicity assays are important, as they allow predicting possible damage that a molecule can cause, and in silico studies predict the pharmacokinetic properties. The aim of this study was to verify the antifungal activity and the mechanism of action of the synthetic amide 2-chloro-N-phenylacetamide against Aspergillus niger strains and toxicity. 2-Chloro-N-phenylacetamide showed antifungal activity against different strains of Aspergillus niger with minimum inhibitory concentrations between 32 and 256 µg/mL and minimum fungicides between 64 and 1024 µg/mL. The minimum inhibitory concentration of 2-chloro-N-phenylacetamide also inhibited conidia germination. When associated with amphotericin B or voriconazole, 2-chloro-N-phenylacetamide had antagonistic effects. Interaction with ergosterol in the plasma membrane is the probable mechanism of action.2-Chloro-N-phenylacetamide has favorable physicochemical parameters, good oral bioavailability and absorption in the gastrointestinal tract, crosses the blood-brain barrier and inhibits CYP1A2. At concentrations of 50 to 500 µg/mL, it has little hemolytic effect and a protective effect for type A and O red blood cells, and in the cells of the oral mucosa it promotes little genotoxic change. It is concluded that 2-chloro-N-phenylacetamide has promising antifungal potential, favorable pharmacokinetic profile for oral administration and low cytotoxic and genotoxic potential, being a promising candidate for in vivo toxicity studies.

Pre-Steady-State and Steady-State Kinetic Analysis of Butyrylcholinesterase-Catalyzed Hydrolysis of Mirabegron, an Arylacylamide Drug.

The ß-adrenergic drug Mirabegron, a drug initially used for the treatment of an overactive bladder, has new potential indications and is hydrolyzed by butyrylcholinesterase (BChE). This compound is one of the only arylacylamide substrates to be catabolized by BChE. A steady-state kinetic analysis at 25 °C and pH 7.0 showed that the enzyme behavior is Michaelian with this substrate and displays a long pre-steady-state phase characterized by a burst. The induction time, τ, increased with substrate concentration (τ ≈ 18 min at maximum velocity). The kinetic behavior was interpreted in terms of hysteretic behavior, resulting from a slow equilibrium between two enzyme active forms, E and E'. The pre-steady-state phase with the highest activity corresponds to action of the E form, and the steady state corresponds to action of the E' form. The catalytic parameters were determined as kcat = 7.3 min-1 and Km = 23.5 µM for the initial (burst) form E, and kcat = 1.6 min-1 and Km = 3.9 µM for the final form E'. Thus, the higher affinity of E' for Mirabegron triggers the slow enzyme state equilibrium toward a slow steady state. Despite the complexity of the reaction mechanism of Mirabegron with BChE, slow BChE-catalyzed degradation of Mirabegron in blood should have no impact on the pharmacological activities of this drug.

Development and validation of stability indicating RP-HPLC method for simultaneous estimation of silodosin and mirabegron in synthetic mixture.

The study focuses to validate and develop a precise, simple and accurate stability indicating RP-HPLC method for estimation simultaneously of and silodosin and mirabegron in synthetic mixture. The chromatographic separation was achieved by using Shimpack Solar C18 column (250×4.5mm, 5µm) with acetonitrile: 5mM ammonium acetate in ratio of 90:10% v/v as a mobile phase at a constant flow rate of about 1.2mL/min. The development and validation were carried out at detection wavelength of 229nm. We developed a robust RP-HPLC method, validated for linearity, precision, accuracy, specificity, and system suitability. The method demonstrated excellent linearity with correlation coefficient value r2 was nearly 0.998 with linearity range 8-18µg/mL for Silodosin and 24-54µg/mL for mirabegron. LOD and LOQ were found to be lower; hence, the method is sensitive. Percentage recovery was obtained 99.97% and 99.99% for silodosin and mirabegron, respectively. In case of precision, robustness and repeatability, RSD was found to be less than 2. The validated and developed RP-HPLC method offers an efficient and practical approach for the simultaneous quantification of silodosin and mirabegron in pharmaceutical formulations, making it a valuable tool for quality control and pharmaceutical research.

MIRABEGRON INDUCED RELAXATION OF ISOLATED BOVINE CORONARY SEGMENTS: ROLE OF NO AND K+ CHANNEL.

It was already known that mirabegron, a ß3-adrenoceptor agonist, affected cardiac muscle, data also demonstrated that mirabegron induced a relaxant effect in rat aortic vessels by a mechanism dependent on nitric oxide production. This study examined the possible effects of mirabegron on the coronary vascular tone. Results show that mirabegron induced an acute relaxant effect on coronary segments' contractility, and the relaxation is partly dependent on nitric oxide and K+ channel activation. These findings emphasize the need to consider these mechanisms when translating mirabegron's effects to clinical applications. Mirabegron, the first approved ß3-adrenoceptor agonist, has demonstrated positive effects in heart failure. Research indicates that ß3 agonists induce prompt relaxation in rat aortic and human coronary vessels through a pathway mediated by NO. This study examined mirabegron's influence on bovine coronary segments' contractility. Using isolated tissue baths, the impact of mirabegron on bovine coronary artery segments' contractility was assessed. The plasma level of NO was measured with a specialized kit. NO was determined by measuring plasma nitrite concentrations by spectrophotometric analysis at 540 nm. Mirabegron evoked relaxation in bovine coronary artery segments in a dose-dependent manner. However, this effect was inhibited by the presence of potassium chloride (KCl) (70mM) and methylene blue (30µM). Both potassium channel and NO pathways were found to play a role in the relaxations induced by mirabegron. Furthermore, mirabegron was observed to enhance in vivo nitric oxide (NO) levels, a crucial signaling molecule maintaining cardiovascular equilibrium. Our findings illustrate that mirabegron induces coronary vessel relaxation through the activation of both NO and K+ channels. These findings emphasize the need to consider these mechanisms when translating mirabegron's effects to clinical applications.

PERIOCULAR HIGH RISK BCCS AFTER ADDITIONAL/PARALLEL INTAKE OF TORASEMIDE, MOXONIDINE AND MIRABEGRON: IMPORTANT LINKS TO SKIN CANCER RELATED (PHOTO-) NITROSOGENESIS IN THE CONTEXT OF PHARMACO-ONCOGENESIS.

The Nitrosogenesis of skin cancer is a modern newly introduced concept in medicine, mainly concerning melanoma, but also keratinocytic cancers such as basal cell carcinoma. The nitroso-contamination of more than 300 drugs worldwide and the permanent (relatively short-term) intake of mutagen-contaminated drugs could create serious prerequisites for the development of skin cancer. Retrospective but also prospective analyses following potentially contaminated polymedication with a heterogeneous type of nitrosamines in real patients are indicative of a causal connection rather than a sporadic association between 1) intake of a possibly nitrosamine-contaminated drug and 2) generation of keratinocytic skin cancer. The pathogenesis of high-risk periocular localized basal cell carcinomas was until recently shrouded in mystery as it was mainly and until now associated with 1) intake of phototoxic drugs and 2) intense exposure to UV radiation (without intake of drugs), 3) congenital or acquired immunodeficiencies, and 4) Goltz Gorlin syndrome or 5) Xeroderma pigmentosum. Nitrosamines/ NDSRIs within the framework of polycotaminated drug intake appear to be one reasonable additional explanation for the association between carcinogen intake and subsequent skin cancer development and progression, and a relatively short-term one at that. Recently published scientific data provide information on a new ability of some of the nitrosamines - namely that some of them are photocarcinogenic or genotoxic after activation with UVA radiation. We present 4 patients who developed high-risk periocular localized basal cell carcinomas of the skin after/within the intake of potentially nitrosamine-contaminated drugs. The presented data are confirmatory with respect to previously published scientific observations on the carcinogenic effects of valsartan, candesartan, bisoprolol, metoprolol, perindopril, lisinopril and amlodipine. The contribution of newly validated data concerning potential/actual carcinogenic/genotoxic activity in the article is also due to the following newly announced nitroso preparations: torasemide, moxonidine and mirabegron. The expansion of the ˝bases of the pyramid˝ determining the stability of drug related (Photo) Nitrosogenesis/ Carcinogenesis (in terms of skin cancer generation) is growing daily. Exogenously/drug-induced Nitrosogenesis and the subsequently triggered carcinogenesis are a completely new explanatory concepts concerning the pathogenesis of skin tumors that remained unanalyzed and hidden for decades. Until now. The official lack of 1) availability, and of 2) precise concentrations regarding nitrosamines in medicinal preparations, are some of the most unexplained acts of irresponsibility to end-users and remain for the moment without a definitive answer from either regulators and manufacturers respectively. Polycontamination of polymedication in polymorbid patients remains highly problematic, at least as a cofactor in the development and progression of keratinocytic cancers, and this in the short term. Recently published data but also data from the past are suggestive that nitrosamines in tobacco are pivotal in the development of acquired mutations in p53 and RAS oncogenes in humans and rodents. The same genes are also affected by mutations in keratinocytic cancer patients. The overlapping mutation patterns of UV radiation-induced mutations in target genes such as p53 and RAS with those caused by some nitrosamines is indicative of a synergism available in terms of gene toxicity or possibly photocarcinogenicity of the latter. What leads the scientific community to believe that the nitrosamines in drugs, similar in composition and carcinogenic potency, act differently, is unclear. The link between drug intake, nitrosamine contamination, generation of some acquired mutations and subsequent cancer development becomes more than obvious and logically conditioned. The thesis of the controlled spread of cancer sounds more than logical today because: whoever controls and regulates the spread of carcinogens/mutagens/nitrosamines is also able to control the occurrence and spread of skin cancer. The Pharmaco-oncogenesis of skin cancer is determined by exogenously mediated Nitrosogenesis or the permissive availability for certain nitrosamines in drugs worldwide.

TRPA1 promotes cisplatin-induced acute kidney injury via regulating the endoplasmic reticulum stress-mitochondrial damage.

BACKGROUND: Cisplatin is a widely used and effective chemotherapeutic agent against cancer. However, nephrotoxicity is one of the most common side effects of cisplatin, and it can proceed to acute kidney injury (AKI). Studies have reported that activation of transient receptor potential ankyrin-1 (TRPA1) mediates cisplatin-induced renal tubular cytotoxic injury. The aim of this study was to investigate the mechanism of TRPA1 in promoting cisplatin-induced AKI through modulation of the endoplasmic reticulum stress (ERS)-mitochondrial damage. METHODS: A cisplatin-induced HK-2 cell model in vitro and mouse model in vivo were established. The mechanism of TRPA1 promotes AKI was elucidated by H&E staining, TUNEL staining, transmission electron microscope (TEM), immunofluorescence, CCK-8 viability assays, flow cytometry, Western blotting, JC-1 assay, and enzyme linked immunosorbent assay (ELISA). RESULT: In vivo and in vitro, HC-030031 reduced cisplatin-induced Scr and BUN level elevations; improved cisplatin-induced renal tissue injury, apoptosis, and mitochondrial dysfunction; elevated the reduced ERS-associated proteins glucose-regulated protein 78 (GRP78), glucose-regulated protein 75 (GRP75), and C/EBP homologous protein (CHOP) levels induced by cisplatin; reduced the elevated optic atrophy 1 (OPA1), mito-fusion 1 (MFN1), and mito-fusion 2 (MFN2) protein levels, and elevated phospho-dynamin-related protein 1 (p-DRP1) and mitochondrial fission factor (MFF) protein levels. HC-030031 also reduced the mitochondria-associated endoplasmic reticulum membrane (MAM) structure. In addition, TRPA1 agonists also decreased cell proliferation, increased apoptosis, and triggered mitochondrial dysfunction and calcium overload in HK-2 cells via modulation of MAM. ERS inhibitors and GRP75 inhibitors reversed these changes caused by TRPA1 agonists. CONCLUSION: Our findings suggest that TRPA1 enhances cisplatin-induced AKI via modulation of ERS and mitochondrial damage.

Biomineralization of pretilachlor by free and immobilized fungal strains isolated from paddy field.

The excessive use of pretilachlor (a chloroacetamide herbicide) has raised concern throughout the world as it has been reported as highly toxic. The present study deals with isolating and screening pretilachlor degrading fungal strains. The strains Aspergillus ficuum (AJN2) and Aspergillus sp. (PDF1) isolated using enrichment technique were able to degrade 79% and 73% of pretilachlor respectively as analyzed using HPLC. Further, the immobilization technique was used in the study the pretilachlor degradation ability of the isolated strains. The immobilized spores of the strains AJN2 and PDF1 mineralized 84% and 95% of pretilachlor respectively. The degradation dynamics study revealed that the DT50 value of the herbicide was reduced to 2.4 d in aqueous medium due to the enhanced enzymatic activity. The enzymatic study showed high lignin peroxidase and manganese peroxidase activity by the strains AJN2 and PDF1 respectively. The study confirmed the efficient degradation of pretilachlor by Aspergillus ficuum (AJN2).