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Microcirculation (New York, N.Y. : 1994) Jun 2024The sympathetic-parasympathetic (or axo-axonal) interaction mechanism mediated that neurogenic relaxation, which was dependent on norepinephrine (NE) releases from...
OBJECTIVE
The sympathetic-parasympathetic (or axo-axonal) interaction mechanism mediated that neurogenic relaxation, which was dependent on norepinephrine (NE) releases from sympathetic nerve terminal and acts on β-adrenoceptor of parasympathetic nerve terminal, has been reported. As NE is a weak β-adrenoceptor agonist, there is a possibility that synaptic NE is converted to epinephrine by phenylethanolamine-N-methyltransferase (PNMT) and then acts on the β-adrenoceptors to induce neurogenic vasodilation.
METHODS
Blood vessel myography technique was used to measure relaxation and contraction responses of isolated basilar arterial rings of rats.
RESULTS
Nicotine-induced relaxation was sensitive to propranolol, guanethidine (an adrenergic neuronal blocker), and N-nitro-l-arginine. Nicotine- and exogenous NE-induced vasorelaxation was partially inhibited by LY-78335 (a PNMT inhibitor), and transmural nerve stimulation depolarized the nitrergic nerve terminal directly and was not inhibited by LY-78335; it then induced the release of nitric oxide (NO). Epinephrine-induced vasorelaxation was not affected by LY-78335. However, these vasorelaxations were completely inhibited by atenolol (a β-adrenoceptor antagonist) combined with ICI-118,551 (a β-adrenoceptor antagonist).
CONCLUSIONS
These results suggest that NE may be methylated by PNMT to form epinephrine and cause the release of NO and vasodilation. These results provide further evidence supporting the physiological significance of the axo-axonal interaction mechanism in regulating brainstem vascular tone.
PubMed: 38837563
DOI: 10.1111/micc.12858 -
Metabolic Brain Disease Jun 2024Apoptosis is the crucial pathological mechanism following cerebral ischemic injury. Our previous studies demonstrated that clonidine, one agonist of alpha2-adrenergic...
Apoptosis is the crucial pathological mechanism following cerebral ischemic injury. Our previous studies demonstrated that clonidine, one agonist of alpha2-adrenergic receptor (α2-AR), could attenuate cerebral ischemic injury in a rat model of middle cerebral artery occlusion/reperfusion (MCAO/R). However, it's unclear whether clonidine exerts neuroprotective effects by regulating neuronal apoptosis. In this study, we elucidated whether clonidine can exert anti-apoptotic effects in cerebral ischemic injury, and further explored the possible mechanisms. Neurological deficit score was measured to evaluate the neurological function. TTC staining was used for the measurement of brain infarct size. Hematoxylin-Eosin (HE) staining was applied to examine the cell morphology. TUNEL and DAPI fluorescent staining methods were used to analyze the cell apoptosis in brain tissue. Fluorescence quantitative real-time PCR was performed to assess the gene expression of Caspase-3 and P53. Western blotting assay was applied to detect the protein expression of Caspase-3 and P53. The results showed that clonidine improved neurological function, reduced brain infarct size, alleviated neuronal damage, and reduced the ratio of cell apoptosis in the brain with MCAO/R injury. moreover, clonidine down-regulated the gene and protein expression of Caspase-3 and P53 which were over-expressed after MCAO/R injury. Whereas, yohimbine (one selective α2-AR antagonist) mitigated the anti-apoptosis effects of clonidine, accompanied by reversed gene and protein expression changes. The results indicated that clonidine attenuated cerebral MCAO/R injury via suppressing neuronal apoptosis, which may be mediated, at least in part, by activating α2-AR.
PubMed: 38833094
DOI: 10.1007/s11011-024-01354-3 -
Cardiovascular Research Jun 2024Glucagon-like peptide-1 receptor agonists (GLP-1 RAs) are increasingly used to treat type 2 diabetes and obesity. Albeit cardiovascular outcomes generally improve,...
AIMS
Glucagon-like peptide-1 receptor agonists (GLP-1 RAs) are increasingly used to treat type 2 diabetes and obesity. Albeit cardiovascular outcomes generally improve, treatment with GLP-1 RAs is associated with increased heart rate, the mechanism of which is unclear.
METHODS AND RESULTS
We employed a large animal model, the female landrace pig, and used multiple in-vivo and ex-vivo approaches including pharmacological challenges, electrophysiology and high-resolution mass spectrometry to explore how GLP-1 elicits an increase in heart rate. In anaesthetized pigs, neither cervical vagotomy, adrenergic blockers (alpha, beta or combined alpha-beta blockade), ganglionic blockade (hexamethonium) nor inhibition of hyperpolarization-activated cyclic nucleotide-gated (HCN) channels (ivabradine) abolished the marked chronotropic effect of GLP-1. GLP-1 administration to isolated perfused pig hearts also increased heart rate, which was abolished by GLP-1 receptor blockade. Electrophysiological characterization of GLP-1 effects in vivo and in isolated perfused hearts localized electrical modulation to the atria and conduction system. In isolated sinus nodes, GLP-1 administration shortened action potential cycle length of pacemaker cells and shifted the site of earliest activation. The effect was independent of HCN blockade. Collectively, these data support a direct effect of GLP-1 on GLP-1 receptors within the heart. Consistently, single nucleus RNA sequencing (snRNAseq) showed GLP-1 receptor expression in porcine pacemaker cells. Quantitative phosphoproteomics analyses of sinus node samples revealed that GLP-1 administration leads to phosphorylation changes of calcium cycling proteins of the sarcoplasmic reticulum, known to regulate heart rate.
CONCLUSION
GLP-1 has direct chronotropic effects on the heart mediated by GLP-1 receptors in pacemaker cells of the sinus node, inducing changes in action potential morphology and the leading pacemaker site through a calcium signaling response characterized by PKA-dependent phosphorylation of Ca2+ cycling proteins involved in pace making. Targeting the pacemaker calcium clock may be a strategy to lower heart rate in GLP-1 RA recipients.
PubMed: 38832935
DOI: 10.1093/cvr/cvae120 -
The Journal of Biological Chemistry Jun 2024During postnatal cardiac hypertrophy, cardiomyocytes undergo mitotic exit, relying on DNA replication-independent mechanisms of histone turnover to maintain chromatin...
During postnatal cardiac hypertrophy, cardiomyocytes undergo mitotic exit, relying on DNA replication-independent mechanisms of histone turnover to maintain chromatin organization and gene transcription. In other tissues, circadian oscillations in nucleosome occupancy influence clock-controlled gene expression, suggesting a role for the circadian clock in temporal control of histone turnover and coordinated cardiomyocyte gene expression. We sought to elucidate roles for the master circadian transcription factor, Bmal1, in histone turnover, chromatin organization, and myocyte-specific gene expression and cell growth in the neonatal period. Bmal1 knockdown in neonatal rat ventricular myocytes decreased myocyte size, total cellular protein synthesis, and transcription of the fetal hypertrophic gene Nppb after treatment with serum or the α-adrenergic agonist phenylephrine. Depletion of Bmal1 decreased the expression of clock-controlled genes Per2 and Tcap, as well as Sik1, a Bmal1 target upregulated in adult versus embryonic hearts. Bmal1 knockdown impaired Per2 and Sik1 promoter accessibility as measured by micrococcal nuclease-quantitative PCR and impaired histone turnover as measured by metabolic labeling of acid-soluble chromatin fractions. Sik1 knockdown in turn decreased myocyte size, while simultaneously inhibiting natriuretic peptide B transcription and activating Per2 transcription. Linking these changes to chromatin remodeling, depletion of the replication-independent histone variant H3.3a inhibited myocyte hypertrophy and prevented phenylephrine-induced changes in clock-controlled gene transcription. Bmal1 is required for neonatal myocyte growth, replication-independent histone turnover, and chromatin organization at the Sik1 promoter. Sik1 represents a novel clock-controlled gene that coordinates myocyte growth with hypertrophic and clock-controlled gene transcription. Replication-independent histone turnover is required for transcriptional remodeling of clock-controlled genes in cardiac myocytes in response to growth stimuli.
PubMed: 38830405
DOI: 10.1016/j.jbc.2024.107434 -
Spectrochimica Acta. Part A, Molecular... Oct 2024The USFDA recently approved mirabegron, a novel once-daily β-3 adrenoceptor agonist for oral administration, as a transformative treatment for overactive bladder....
Integrated approach of white analytical chemistry and design of experiments to microwave-assisted sensitive and eco-friendly spectrofluorimetric estimation of mirabegron using 4-chloro-7-nitrobezofuran as biosensing fluorescent probe.
The USFDA recently approved mirabegron, a novel once-daily β-3 adrenoceptor agonist for oral administration, as a transformative treatment for overactive bladder. Despite the existence of numerous analytical methods for the assay and bioanalysis of mirabegron, it's perplexing that none have explored the domain of microwave-assisted sensitive spectrofluorimetric method for mirabegron estimation, even after extensive literature review. Adding to the enigma is the insistence of current analytical methods on using expensive and harmful organic solvents, posing a threat to marine life and the broader environment. Recently, the white analytical chemistry approach has been introduced to develop analytical methods that are cost-effective, environmentally friendly, and user-friendly. Consequently, a white analytical chemistry-based, sensitive, and eco-friendly spectrofluorimetric estimation of mirabegron has been initiated, using 4-Chloro-7-nitrobenzofurazan as a fluorescent biosensing probe. The development of this robust method involved a series of experiments designed to minimize solvent and time wastage. Through a combination of fractional factorial and Box-Behnken designs, researchers identified the critical variables and optimized the method to perfection. This method was validated according to the stringent ICH Q2 (R2) and USFDA guidelines, ensuring its reliability and accuracy. Once approved, this sensitive spectrofluorimetric method was tested, accurately estimating mirabegron levels in commercial formulations and rat plasma samples. To further enrich the study, a comprehensive evaluation of existing analytical methods was conducted alongside the proposed spectrofluorimetric method, using advanced tools like the AGREE calculator, GAPI software, and RGB model to assess their eco-friendliness and effectiveness in mirabegron estimation.
Topics: Thiazoles; Acetanilides; Animals; Fluorescent Dyes; Spectrometry, Fluorescence; Microwaves; Biosensing Techniques; Green Chemistry Technology; Reproducibility of Results; Rats; Limit of Detection; Male
PubMed: 38830329
DOI: 10.1016/j.saa.2024.124521 -
Respiratory Research May 2024COPD is associated with the development of lung cancer. A protective effect of inhaled corticosteroids (ICS) on lung cancer is still controversial. Hence, this study...
BACKGROUND
COPD is associated with the development of lung cancer. A protective effect of inhaled corticosteroids (ICS) on lung cancer is still controversial. Hence, this study investigated the development of lung cancer according to inhaler prescription and comorbidties in COPD.
METHODS
A retrospective cohort study was conducted based on the Korean Health Insurance Review and Assessment Service database. The development of lung cancer was investigated from the index date to December 31, 2020. This cohort included COPD patients (≥ 40 years) with new prescription of inhalers. Patients with a previous history of any cancer during screening period or a switch of inhaler after the index date were excluded.
RESULTS
Of the 63,442 eligible patients, 39,588 patients (62.4%) were in the long-acting muscarinic antagonist (LAMA) and long-acting β2-agonist (LABA) group, 22,718 (35.8%) in the ICS/LABA group, and 1,136 (1.8%) in the LABA group. Multivariate analysis showed no significant difference in the development of lung cancer according to inhaler prescription. Multivariate analysis, adjusted for age, sex, and significant factors in the univariate analysis, demonstrated that diffuse interstitial lung disease (DILD) (HR = 2.68; 95%CI = 1.86-3.85), a higher Charlson Comorbidity Index score (HR = 1.05; 95%CI = 1.01-1.08), and two or more hospitalizations during screening period (HR = 1.19; 95%CI = 1.01-1.39), along with older age and male sex, were independently associated with the development of lung cancer.
CONCLUSION
Our data suggest that the development of lung cancer is not independently associated with inhaler prescription, but with coexisting DILD, a higher Charlson Comorbidity Index score, and frequent hospitalization.
Topics: Humans; Male; Female; Lung Neoplasms; Middle Aged; Retrospective Studies; Aged; Pulmonary Disease, Chronic Obstructive; Republic of Korea; Administration, Inhalation; Nebulizers and Vaporizers; Adult; Cohort Studies; Adrenal Cortex Hormones; Population Surveillance; Adrenergic beta-2 Receptor Agonists; Muscarinic Antagonists
PubMed: 38822332
DOI: 10.1186/s12931-024-02838-7 -
The Journal of Clinical Endocrinology... May 2024Given the promising effects of prolonged treatment with beta2-agonist on insulin sensitivity in animals and non-diabetic individuals, the beta2-adrenergic receptor has...
CONTEXT
Given the promising effects of prolonged treatment with beta2-agonist on insulin sensitivity in animals and non-diabetic individuals, the beta2-adrenergic receptor has been proposed as a target to counter peripheral insulin resistance. On the other hand, rodent studies also reveal that beta2-agonists acutely impair insulin action, posing a potential caveat for their use in treating insulin resistance.
OBJECTIVE
To assess the impact of beta2-agonist on muscle insulin action and glucose metabolism and identify the underlying mechanism(s) in 10 insulin-resistant subjects.
METHODS AND PARTICIPANTS
In a cross-over design, we assessed the effect of beta2-agonist on insulin-stimulated muscle glucose uptake during a 3-h hyperinsulinemic isoglycemic clamp with and without intralipid infusion in 10 insulin-resistant overweight subjects. Two hours into the clamp, we infused beta2-agonist. We collected muscle biopsies before, two hours into and by the end of the clamp and analyzed them using metabolomic and lipidomic techniques.
RESULTS
We establish that beta2-agonist, independently from and additively to intralipid, impairs insulin-stimulated muscle glucose uptake via different mechanisms. In combination, beta2-agonist and intralipid nearly eliminates insulin-dependent muscle glucose uptake. While both beta2-agonist and intralipid elevated muscle glucose-6-phosphate, only intralipid caused accumulation of downstream muscle glycolytic intermediates, whereas beta2-agonist attenuated incorporation of glucose into glycogen.
CONCLUSIONS
Our findings suggest that beta2-agonist inhibits glycogenesis while intralipid inhibits glycolysis in skeletal muscle of insulin-resistant individuals. These results should be addressed in future treatment of insulin resistance with beta2-agonist.
PubMed: 38820114
DOI: 10.1210/clinem/dgae381 -
Current Medicinal Chemistry May 2024Beta-1-adrenergic receptor antibodies (β1-AAbs) function as arrhythmogenic molecules in autoimmune-related atrial fibrillation (AF). This study examined the potential...
BACKGROUND
Beta-1-adrenergic receptor antibodies (β1-AAbs) function as arrhythmogenic molecules in autoimmune-related atrial fibrillation (AF). This study examined the potential impact of pioglitazone, an agonist for peroxisome proliferator-activated receptor-γ (PPAR-γ), on atrial remodeling induced by β1-AAbs.
METHODS
An in vivo study was performed to confirm the protective effects of pioglitazone on β1- AAbs-induced atrial remodeling. GW9662, a PPAR-γ antagonist, was employed to identify the potential therapeutic target of pioglitazone. The rats were administered subcutaneous injections of the second extracellular loop peptide for 8 weeks to establish active immunization models. Pioglitazone was then administered orally for 2 weeks. Epicardial electrophysiologic studies, multielectrode array measurements, and echocardiography were conducted to examine atrial remodeling. Glucose metabolism products and key metabolic molecules were measured to evaluate the atrial substrate metabolism. Mitochondrial morphologies and function indices were tested to depict the underlying links between atrial metabolism and mitochondrial homeostasis under the pioglitazone treatment.
RESULTS
Pioglitazone significantly reversed β1-AAbs-induced AF susceptibility, ameliorated atrial structural remodeling, decreased the global insulin resistance reflected in the plasma glucose and insulin levels, and increased the protein expressions of glycolipid uptake and transportation (GLUT1, CD36, and CPT1a). These trends were counterbalanced by the GW9662 intervention. Mechanistically, pioglitazone mitigated the atrial mitochondrial network damage and partly renovated the mitochondrial biogenesis, even the mitochondrial dynamics, which were reversed by inhibiting the PPAR-γ target.
CONCLUSION
Pioglitazone effectively reduced the AF vulnerability and recovered the atrial myocardial metabolism and mitochondrial damage. The potential anti-remodeling effect of pioglitazone on the atrium was associated with the moderately increased expression of key membrane proteins related to glucose transporter and fatty acid uptake, which may promote the increased myocardial preference for utilization of FA as the key cardiac oxidative fuel and ameliorate the atrial metabolic inflexibility.
PubMed: 38818915
DOI: 10.2174/0109298673308673240527092317 -
Journal of Cardiovascular Pharmacology May 2024Exercise preconditioning has been shown to protect against DOX-induced cardiac dysfunction when hearts are maintained under resting conditions. However, it is unclear...
Exercise preconditioning has been shown to protect against DOX-induced cardiac dysfunction when hearts are maintained under resting conditions. However, it is unclear whether this exercise-induced protective effect is maintained when the heart is challenged with the β1-adrenergic receptor agonist dobutamine (DOB), which mimics acute exercise stress. Fischer 344 rats were randomly assigned to sedentary (SED) or voluntary wheel running (WR) groups for 10 weeks. At week 11, rats were treated with either 15 mg/kg DOX or saline (SAL). Five days later, ex vivo cardiac function was assessed using an isolating working heart model at baseline, during the infusion of 7.5 μg/kg/min DOB, and during recovery. DOB infusion significantly increased left ventricular developed pressure (LVDP), maximal (dP/dtmax) and minimal (dP/dtmin) rate of left ventricular pressure development, and heart rate in all groups (p<0.05). SED+DOX also showed a lower baseline and recovery LVDP than WR+DOX (83 ± 12 vs. 109 ± 6 mmHg baseline, 76 ± 11 vs. 100 ± 10 mmHg recovery, p<0.05). WR+DOX showed higher dP/dtmax and lower dP/dtmin when compared to SED+DOX during DOB infusion (7311 ± 1481 vs. 5167 ± 1436 mmHg/s and -4059 ± 1114 vs.-3158 ± 1176 mmHg/s, respectively). SED+DOX dP/dtmax was significantly lower during baseline and during recovery when compared to all other groups (p<0.05). These data suggest that exercise preconditioning preserved cardiac function after DOX exposure even when the heart is challenged with DOB, and it appeared to preserve the heart's ability to recover from this functional challenge.
PubMed: 38814887
DOI: 10.1097/FJC.0000000000001583 -
International Journal of Chronic... 2024Real-life research is needed to evaluate the effectiveness of budesonide/glycopyrrolate/formoterol (BGF) in routine COPD primary care management. We assessed the... (Observational Study)
Observational Study
PURPOSE
Real-life research is needed to evaluate the effectiveness of budesonide/glycopyrrolate/formoterol (BGF) in routine COPD primary care management. We assessed the frequency of medication success among patients with COPD who initiated BGF using real-world data.
PATIENTS AND METHODS
Patients with a recorded diagnostic COPD code who started BGF with ≥2 prescriptions within 90-days were identified in the UK Optimum Patient Care Research Database and followed from first prescription until censoring at the end of follow-up (180-days), death, leaving database or end of data at 24/10/2022. The primary outcome was medication success at 90-days post-BGF initiation, defined as no major cardiac or respiratory event (ie no complicated COPD exacerbation, hospitalization for any respiratory event, myocardial infarction, new/hospitalized heart failure, and death) and no incidence of pneumonia. Medication success was also assessed at 180-days post-BGF initiation. Overall real-life medication success was claimed if the lower 95% confidence interval (CI) for the proportion of patients meeting the primary outcome was ≥70% (defined a priori).
RESULTS
Two hundred eighty-five patients were included. Prior to BGF initiation, these patients often had severe airflow obstruction (mean ppFEV: 54.5%), were highly symptomatic (mMRC ≥2: 77.9% (n = 205/263); mean CAT score: 21.7 (SD 7.8)), with evidence of short-acting β-agonist (SABA) over-use (≥3 inhalers/year: 62.1%, n=179/285), repeat OCS prescriptions (≥2 courses/year: 33.0%, n = 95/285) and multiple primary care consultations (≥2 visits/year: 61.1%, n = 174/285). Overall, 39.6% of patients (n = 113/285) switched from previous triple therapies. Real-life medication success was achieved by 96.5% of patients (n = 275/285 [95% CI: 93.6, 98.3]) during 90-days treatment with BGF and by 91.8% (n = 169/184 [95% CI: 86.9, 95.4]) of patients at 180-days. The prescribed daily dose of SABA remained stable over the study period.
CONCLUSION
The majority of patients initiating BGF experienced real-life medication success reflecting the absence of severe cardiopulmonary events. These benefits were apparent after 90-days of treatment and sustained over 180-days.
Topics: Humans; Pulmonary Disease, Chronic Obstructive; Male; Female; Aged; Primary Health Care; Treatment Outcome; Bronchodilator Agents; Middle Aged; Time Factors; Adrenergic beta-2 Receptor Agonists; United Kingdom; Glycopyrrolate; Databases, Factual; Budesonide, Formoterol Fumarate Drug Combination; Lung; Muscarinic Antagonists; Drug Combinations; Retrospective Studies; Glucocorticoids; Aged, 80 and over
PubMed: 38813078
DOI: 10.2147/COPD.S452624