Three Generation ß-Blockers for Atrial Fibrillation Treatment.

The efficiency of blood flowing from the heart depends on its electrical properties. Myocardial electrical activity is associated with generating cardiac action potentials in isolated myocardial cells and their coordinated propagation, which are mediated by gap junctions. Atrial fibrillation (AF) is a common cardiac arrhythmia which causes an aggressive disturbance in cardiac electromechanical function. Moreover, AF increases the risk of stroke and mortality and is a major cause of death. The mechanisms underlying AF involve electrophysiological changes in ion channel expression and function. ß-blockers may be useful in patients with chronic AF or in preventing postoperative AF in subjects undergoing coronary artery bypass grafting (CABG) or other types of surgery. The reduction in heart rate induced by ß1-adrenergic receptor antagonists may be associated with the beneficial effect of this drug class. Second generation beta-blockers may be considered superior to the first generation due to their selectivity to the ß1 receptor as well as avoiding pulmonary or metabolic adverse effects. Third generation beta-blockers may be considered a great option for their vasodilation and antioxidant properties. There is also a new ß-blocker, named landilol that also results on reduced risk of post operative AF without adverse effects and its use has been increasing in clinical trials.

Safety of intravitreal metoprolol in eyes with central serous chorioretinopathy.

PURPOSE: To investigate ocular safety of intravitreal metoprolol in eyes with central serous chorioretinopathy. METHODS: Five eyes of five patients diagnosed with chronic central serous chorioretinopathy (cCSC) previously treated unsuccessfully with oral spironolactone, micropulse laser and intravitreal anti-vascular endothelial growth factor agents were enrolled and received off-label intravitreal metoprolol (50 µg/0.05 ml). Baseline and follow-up examinations included measurement of best-corrected visual acuity (BCVA), intraocular pressure, anterior chamber cellular/flare scores, vitritis classification, fluorescein and indocyanine green angiography, spectral domain optical coherence tomography and electroretinography (ERG), recorded by means of DTL electrodes and following the standard suggested by the International Society for Clinical Electrophysiology of Vision (ISCEV). The total follow-up period was 4 weeks. RESULTS: There were no significant differences between baseline and follow-up ERG parameters: scotopic or photopic, a- and b-wave amplitude and implicit time, nor oscillatory potentials amplitude, or whatsoever. No intraocular inflammation sign was observed. In addition, BCVA showed small improvement in 4 or kept baseline values in 1 patient. The subretinal and/or intraretinal fluid volume reduced in all patients at 1 month after treatment. CONCLUSION: Patients with refractory cCSC treated with intravitreal 50 µg/0.05 ml metoprolol showed no signs of acute ocular toxicity, along with intraretinal fluid reduction and slight BCVA improvement 1 month after injection. This data suggest that intravitreal metoprolol may be a safe alternative for cCSC.

Effects of ß-blocker therapy on exercise oscillatory ventilation in reduced ejection fraction heart failure patients: A case series study.

BACKGROUND: Exercise oscillatory ventilation (EOV) is an abnormal breathing pattern that occurs in ~20% of patients with heart failure (HF) and is associated with poor prognosis and exercise intolerance. ß-blockers (ßb) are prescribed for most HF patients; however, their effect on EOV remains unclear. We evaluated the effect of ßb on EOV in HF patients with reduced ejection fraction (HFrEF). METHODS: Fifteen patients diagnosed with HF, ejection fraction < 45%, aged from 18 to 65 years, were included before starting ßb therapy. Patients underwent clinical evaluation, cardiopulmonary exercise testing, echocardiography, laboratory exams (norepinephrine levels, B type natriuretic peptide) at baseline and after ßb therapy optimized for six months. Presence of exercise oscillatory breathing was determined by two experienced observers who were blinded to the moment of the test (pre or post). RESULTS: Fifteen patients (1 female), aged 49.5 ± 2.5 years, with HFrEF, NYHA I-III enrolled in the study. The etiologies of the HFrEF were idiopathic (n = 8) and hypertensive (n = 7). LVEF increased after ßb therapy from 25.9 ± 2.5% to 33 ± 2.6%, P = 0.02; peak VO2 did not significantly change (21.8 ± 1.7 vs 24.7 ± 1.9, P = 0.4); VE/VCO2 slope changed from 32.1 ± 10.6-27.5 ± 9.1, P = 0.03. Before ßb initiation, nine patients (60%) had EOV, but only two (13%) did after optimized therapy. McNemar test was used to evaluate the significance of the association between the two moments (P = 0.02). CONCLUSION: In patients with HF, medical therapy with ßb can reverse EOV. This may explain why these patients experience symptom improvement after ßb therapy.

Intravitreal metoprolol for circumscribed choroidal hemangiomas: a phase I clinical trial.

BACKGROUND: Choroidal hemangioma is a visual threatening condition for which treatments is neither uniform nor widely available. New management options are necessary. The purpose of this study is to assess the safety and early outcome of intravitreal metoprolol tartrate in five patients with CCH. METHODS: Five eyes of five patients diagnosed with subfoveal or peripapillary CCH and unsuccessfully treated with intravitreal anti-VEGF agents were enrolled and received off-label intravitreal injections of metoprolol (50µg/0.05 ml). Baseline and follow-up evaluations included best-corrected visual acuity, intraocular pressure measurement, assessment of anterior chamber cellular score/flare and vitritis, retinography, fundus autofluorescence, and ERG. Patients were followed for a period of 30 days. Statistical analysis involved comparison of pre- and post-treatment findings using a paired t-test. RESULTS: There was no significant difference in all ERG parameters regarding a- and b-wave amplitude and implicit time, and oscillatory potentials' maximal amplitude. There were no significant changes in visual acuity. None of the patients developed clinical signs of intraocular inflammation. The subretinal and/or intraretinal fluid improved in 3 out of 5 patients 4 weeks after the metoprolol injection. CONCLUSIONS: Patients with CCH treated with a single injection of 50µg/0.05ml intravitreal metoprolol injections showed no signs of acute ocular toxicity. This pilot study did not assess long-term retinal toxicity, different concentrations, drug resistance, and complications from repeated-intravitreal injections.

Agonist Effects of Propranolol on Non-Tumor Human Breast Cells.

The ß-blocker propranolol (PROP) has been proposed as a repurposed treatment for breast cancer. The similarity of action between ß-agonists and antagonists found on breast cells encouraged us to compare PROP and isoproterenol (ISO, agonist) signaling pathways on a human breast cell line. Cell proliferation was measured by cell counting and DNA-synthesis. Cell adhesion was measured counting the cells that remained adhered to the plastic after different treatments. Changes in actin cytoskeleton were observed by fluorescence staining and Western Blot. ISO and PROP caused a diminution of cell proliferation and an increase of cell adhesion, reverted by the pure ß-antagonist ICI-118551. ISO and PROP induced a reorganization of actin cytoskeleton increasing F-actin, p-COFILIN and p-LIMK. While ISO elicited a marked enhancement of cAMP concentrations and an increase of vasodilator-stimulated phosphoprotein (VASP) and cAMP response element-binding protein (CREB) phosphorylation, PROP did not. Clathrin-mediated endocytosis inhibition or ß-arrestin1 dominant-negative mutant abrogated PROP-induced cell adhesion and COFILIN phosphorylation. The fact that PROP has been proposed as an adjuvant drug for breast cancer makes it necessary to determine the specific action of PROP in breast models. These results provide an explanation for the discrepancies observed between experimental results and clinical evidence.