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Porta LC, Campeiro JD, Papa GB, Oliveira EB, Godinho RO, Rodrigues T, Hayashi MAF. In vivo effects of the association of the psychoactive phenotiazine thioridazine on antitumor activity and hind limb paralysis induced by the native polypeptide crotamine. Toxicon 2020; 185:64-71. [PMID: 32621838 DOI: 10.1016/j.toxicon.2020.06.017] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Revised: 05/28/2020] [Accepted: 06/21/2020] [Indexed: 11/18/2022]
Abstract
Crotamine is a cationic polypeptide composed by 42 amino acid residues with several pharmacological and biological properties, including the selective ability to enter and kill actively proliferating tumour cells, which led us to propose its use as a theranostic agent for cancer therapy. At the moment, the improvement of crotamine antitumoral efficacy by association with chemotherapeutic adjuvants is envisioned. In the present work, we evaluated the association of crotamine with the antitumoral adjuvant phenotiazine thioridazine (THD). In spite of the clear efficacy of these both compounds as anticancer agents in long-term in vivo treatment of animal model bearing implanted xenograph melanoma tumor, the expected mutual potentiation of the antitumor effects was not observed here. Moreover, this association revealed for the first time the influence of THD on crotamine ability to trigger the hind limb paralysis in mice, and this discovery may represent the first report suggesting the potential involvement of the CNS in the action of this snake polypeptide on the skeletal muscle paralysis, which was classically believed to be essentially limited to a direct action in peripheral tissues as the skeletal muscle. This is also supported by the observed ability of crotamine to potentiate the sedative effects of THD which action was consistently demonstrated to be based on its central action. The better characterization of crotamine properties in CNS may certainly bring important insights for the knowledge needed to pave the way toward the use of this molecule as a theranostic compound in human diseases as cancer.
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Affiliation(s)
- Lucas C Porta
- Departamento de Farmacologia, Escola Paulista de Medicina (EPM), Universidade Federal de São Paulo (UNIFESP), SP, Brazil
| | - Joana D Campeiro
- Departamento de Farmacologia, Escola Paulista de Medicina (EPM), Universidade Federal de São Paulo (UNIFESP), SP, Brazil
| | - Giovanna B Papa
- Departamento de Farmacologia, Escola Paulista de Medicina (EPM), Universidade Federal de São Paulo (UNIFESP), SP, Brazil
| | - Eduardo B Oliveira
- Departamento de Bioquímica e Imunologia, Universidade de São Paulo (USP-RP), Ribeirão Preto, Brazil
| | - Rosely O Godinho
- Departamento de Farmacologia, Escola Paulista de Medicina (EPM), Universidade Federal de São Paulo (UNIFESP), SP, Brazil
| | | | - Mirian A F Hayashi
- Departamento de Farmacologia, Escola Paulista de Medicina (EPM), Universidade Federal de São Paulo (UNIFESP), SP, Brazil.
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Schmidt MM, Iaizzo PA. The Visible Heart® project and methodologies: novel use for studying cardiac monophasic action potentials and evaluating their underlying mechanisms. Expert Rev Med Devices 2018; 15:467-477. [PMID: 29989510 DOI: 10.1080/17434440.2018.1493922] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
INTRODUCTION This review describes the utilization of Visible Heart® methodologies for electrophysiologic studies, specifically in the investigation of monophasic action potential (MAP) recordings, with the aim to facilitate new catheter/device design and development that may lead to earlier diagnosis, treatment, and ultimately a higher quality of life for patients with atrial fibrillation. AREAS COVERED We describe the historically proposed mechanisms behind which electrode is responsible for the MAP recording, new catheters for recording these signals, and how Visible Heart methodologies can be utilized to develop and test new technologies for electrophysiologic investigations. EXPERT OPINION When compared to traditional electrogram recordings, MAP waveforms provide clinical information vital to the understanding, diagnosis, and treatment of cardiac arrhythmias. New catheters and ablation technologies are routinely being assessed on reanimated large mammalian hearts (swine and human) in our laboratory. These abilities, combined with continued enhancements in imaging modalities and computational systems for electrical mapping, are being applied to the MAP catheter design process. Through this testing we are hopeful that the time from concept to product can be reduced, and that an array of MAP catheters can be placed in the hands of physicians, where they will improve patient outcomes.
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Affiliation(s)
- Megan M Schmidt
- a Department of Biomedical Engineering , University of Minnesota , Minneapolis , MN , USA
| | - Paul A Iaizzo
- b Department of Surgery , University of Minnesota , Minneapolis , MN , USA
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Sparve E, Quartino AL, Lüttgen M, Tunblad K, Gårdlund AT, Fälting J, Alexander R, Kågström J, Sjödin L, Bulgak A, Al-Saffar A, Bridgland-Taylor M, Pollard C, Swedberg MDB, Vik T, Paulsson B. Prediction and Modeling of Effects on the QTc Interval for Clinical Safety Margin Assessment, Based on Single-Ascending-Dose Study Data with AZD3839. J Pharmacol Exp Ther 2014; 350:469-78. [DOI: 10.1124/jpet.114.215202] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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Holzgrefe H, Ferber G, Champeroux P, Gill M, Honda M, Greiter-Wilke A, Baird T, Meyer O, Saulnier M. Preclinical QT safety assessment: Cross-species comparisons and human translation from an industry consortium. J Pharmacol Toxicol Methods 2014; 69:61-101. [DOI: 10.1016/j.vascn.2013.05.004] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2013] [Revised: 05/08/2013] [Accepted: 05/09/2013] [Indexed: 01/10/2023]
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Townsend C, Brown BS. Predicting drug-induced QT prolongation and torsades de pointes: a review of preclinical endpoint measures. ACTA ACUST UNITED AC 2013; Chapter 10:Unit 10.16. [PMID: 23744708 DOI: 10.1002/0471141755.ph1016s61] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Compound-induced prolongation of the cardiac QT interval is a major concern in drug development and this unit discusses approaches that can predict QT effects prior to undertaking clinical trials. The majority of compounds that prolong the QT interval block the cardiac rapid delayed rectifier potassium current, IKr (hERG). Described in this overview are different ways to measure hERG, from recent advances in automated electrophysiology to the quantification of channel protein trafficking and binding. The contribution of other cardiac ion channels to hERG data interpretation is also discussed. In addition, endpoint measures of the integrated activity of cardiac ion channels at the single-cell, tissue, and whole-animal level, including for example the well-established action potential to the more recent beat-to-beat variability, transmural dispersion of repolarization, and field potential duration, are described in the context of their ability to predict QT prolongation and torsadogenicity in humans.
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Affiliation(s)
- Claire Townsend
- GlaxoSmithKline Biological Reagents and Assay Development, Research Triangle Park, NC, USA
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Safety pharmacology — Current and emerging concepts. Toxicol Appl Pharmacol 2013; 273:229-41. [DOI: 10.1016/j.taap.2013.04.039] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2013] [Revised: 03/31/2013] [Accepted: 04/15/2013] [Indexed: 11/18/2022]
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Morissette P, Nishida M, Trepakova E, Imredy J, Lagrutta A, Chaves A, Hoagland K, Hoe CML, Zrada MM, Travis JJ, Zingaro GJ, Gerenser P, Friedrichs G, Salata JJ. The anesthetized guinea pig: An effective early cardiovascular derisking and lead optimization model. J Pharmacol Toxicol Methods 2013; 68:137-49. [DOI: 10.1016/j.vascn.2013.04.010] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2013] [Revised: 04/19/2013] [Accepted: 04/27/2013] [Indexed: 10/26/2022]
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Takahara A, Fujiwara K, Ohtsuki A, Oka T, Namekata I, Tanaka H. Effects of the antitussive drug cloperastine on ventricular repolarization in halothane-anesthetized guinea pigs. J Pharmacol Sci 2012; 120:165-75. [PMID: 23047467 DOI: 10.1254/jphs.12117fp] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
Abstract
Cloperastine is an antitussive drug, which can be received as an over-the-counter cold medicine. The chemical structure of cloperastine is quite similar to that of the antihistamine drug diphenhydramine, which is reported to inhibit hERG K⁺ channels and clinically induce long QT syndrome after overdose. To analyze its proarrhythmic potential, we compared effects of cloperastine and diphenhydramine on the hERG K⁺ channels expressed in HEK293 cells. We further assessed their effects on the halothane-anesthetized guinea-pig heart under the monitoring of monophasic action potential (MAP) of the ventricle. Cloperastine inhibited the hERG K⁺ currents in a concentration-dependent manner with an IC₅₀ value of 0.027 μM, whose potency was 100 times greater than that of diphenhydramine (IC₅₀; 2.7 μM). In the anesthetized guinea pigs, cloperastine at a therapeutic dose of 1 mg/kg prolonged the QT interval and MAP duration without affecting PR interval or QRS width. Diphenhydramine at a therapeutic dose of 10 mg/kg prolonged the QT interval and MAP duration together with increase in PR interval and QRS width. The present results suggest that cloperastine may be categorized as a QT-prolonging drug that possibly induces arrhythmia at overdoses like diphenhydramine does.
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Affiliation(s)
- Akira Takahara
- Department of Pharmacology and Therapeutics, Faculty of Pharmaceutical Sciences, Toho University, Funabashi, Chiba, Japan.
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Guns PJ, Johnson DM, Van Op den Bosch J, Weltens E, Lissens J. The electro-mechanical window in anaesthetized guinea pigs: a new marker in screening for Torsade de Pointes risk. Br J Pharmacol 2012; 166:689-701. [PMID: 22122450 DOI: 10.1111/j.1476-5381.2011.01795.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
BACKGROUND AND PURPOSE QT prolongation is commonly used as a surrogate marker for Torsade de Pointes (TdP) risk of non-cardiovascular drugs. However, use of this indirect marker often leads to misinterpretation of the realistic TdP risk, as tested compounds may cause QT prolongation without evoking TdP in humans. A negative electro-mechanical (E-M) window has recently been proposed as an alternative risk marker for TdP in a canine LQT1 model. Here, we evaluated the E-M window in anaesthetized guinea pigs as a screening marker for TdP in humans. EXPERIMENTAL APPROACH The effects of various reference drugs and changes in body temperature on the E-M window were assessed in instrumented guinea pigs. The E-M window was defined as the delay between the duration of the electrical (QT interval) and mechanical (QLVP(end) ) systole. KEY RESULTS Drugs with known TdP liability (quinidine, haloperidol, domperidone, terfenadine, thioridazine and dofetilide), but not those with no TdP risk in humans (salbutamol and diltiazem) consistently decreased the E-M window. Interestingly, drugs with known clinical QT prolongation, but with low risk for TdP (amiodarone, moxifloxacin and ciprofloxacin) did not decrease the E-M window. Furthermore, the E-M window was minimally affected by changes in heart rate or body temperature. CONCLUSIONS AND IMPLICATIONS A decreased E-M window was consistently observed with drugs already known to have high TdP risk, but not with drugs with low or no TdP risk. These results suggest that the E-M window in anaesthetized guinea pigs is a risk marker for TdP in humans.
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Affiliation(s)
- P-J Guns
- Bio-Plus Safety Pharmacology, Bio-Plus Services, Mol, Belgium.
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Marks L, Borland S, Philp K, Ewart L, Lainée P, Skinner M, Kirk S, Valentin JP. The role of the anaesthetised guinea-pig in the preclinical cardiac safety evaluation of drug candidate compounds. Toxicol Appl Pharmacol 2012; 263:171-83. [DOI: 10.1016/j.taap.2012.06.007] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2012] [Revised: 06/07/2012] [Accepted: 06/11/2012] [Indexed: 11/30/2022]
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Johnson DM, Geys R, Lissens J, Guns PJ. Drug-induced effects on cardiovascular function in pentobarbital anesthetized guinea-pigs: invasive LVP measurements versus the QA interval. J Pharmacol Toxicol Methods 2012; 66:152-9. [PMID: 22813982 DOI: 10.1016/j.vascn.2012.07.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2012] [Revised: 06/13/2012] [Accepted: 07/05/2012] [Indexed: 11/28/2022]
Abstract
INTRODUCTION Evaluation of drug-related effects on cardiovascular function is part of the core battery described in the ICH S7A guideline. Anesthetized guinea-pigs are excellent models for the evaluation of drug-induced prolongation of ventricular repolarization; however less information is available regarding other cardio-hemodynamic parameters in this model. The current study aimed to document cardio-hemodynamic responses in anesthetized guinea-pigs after administration of a number of reference drugs with known pharmacological actions. METHODS Experiments were carried out in closed chest pentobarbital anesthetized female guinea-pigs. Compounds were administered intravenously while arterial blood pressure, left ventricular pressure (LVP) and the electrocardiogram were measured continuously. The rate of LVP contraction (LV dP/dt(max)) was used to evaluate cardiac performance; and was compared to the QA interval; which has previously been proposed as an indirect measurement of cardiac function. RESULTS Baseline values for heart rate and blood pressure were lower in anesthetized animals compared to literature data of conscious guinea-pigs. Heart rate increased after administration of adrenaline, isoprenaline and salbutamol, but not after L-phenylephrine. Verapamil and amiodarone decreased heart rate and blood pressure. Zatebradine infusion led to a decrease in heart rate with minimal effects on blood pressure. Sodium nitroprusside (SNP) caused a reduction in mean blood pressure at higher doses followed by reflex tachycardia. Both adrenaline and L-phenylephrine increased arterial blood pressure. Furthermore, adrenaline, isoprenaline and salbutamol increased LV dP/dt(max) and decreased the QA interval. L-phenylephrine increased LV dP/dt(max), but transiently prolonged the QA interval. Both verapamil and amiodarone decreased LV dP/dt(max) and prolonged the QA interval, whereas zatebradine did not affect this parameter. DISCUSSION In addition to its utility for the assessment of test compounds on ventricular repolarization the pentobarbital anesthetized guinea-pig model shows promise for early stage cardio-hemodynamic screening. Furthermore, the QA interval shows potential for prediction of adverse effects on cardiac contractility.
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Affiliation(s)
- D M Johnson
- Bio-Plus Safety Pharmacology, Vlasmeer 5/0003, B-2400 Mol, Belgium.
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Wen D, Liu A, Chen F, Yang J, Dai R. Validation of visualized transgenic zebrafish as a high throughput model to assay bradycardia related cardio toxicity risk candidates. J Appl Toxicol 2012; 32:834-42. [PMID: 22744888 DOI: 10.1002/jat.2755] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2012] [Revised: 02/27/2012] [Accepted: 02/27/2012] [Indexed: 11/09/2022]
Abstract
Drug-induced QT prolongation usually leads to torsade de pointes (TdP), thus for drugs in the early phase of development this risk should be evaluated. In the present study, we demonstrated a visualized transgenic zebrafish as an in vivo high-throughput model to assay the risk of drug-induced QT prolongation. Zebrafish larvae 48 h post-fertilization expressing green fluorescent protein in myocardium were incubated with compounds reported to induce QT prolongation or block the human ether-a-go-go-related gene (hERG) K⁺ current. The compounds sotalol, indapaminde, erythromycin, ofoxacin, levofloxacin, sparfloxacin and roxithromycin were additionally administrated by microinjection into the larvae yolk sac. The ventricle heart rate was recorded using the automatic monitoring system after incubation or microinjection. As a result, 14 out of 16 compounds inducing dog QT prolongation caused bradycardia in zebrafish. A similar result was observed with 21 out of 26 compounds which block hERG current. Among the 30 compounds which induced human QT prolongation, 25 caused bradycardia in this model. Thus, the risk of compounds causing bradycardia in this transgenic zebrafish correlated with that causing QT prolongation and hERG K⁺ current blockage in established models. The tendency that high logP values lead to high risk of QT prolongation in this model was indicated, and non-sensitivity of this model to antibacterial agents was revealed. These data suggest application of this transgenic zebrafish as a high-throughput model to screen QT prolongation-related cardio toxicity of the drug candidates.
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Affiliation(s)
- Dingsheng Wen
- South China University of Technology, Guangzhou 510641, China
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Kågström J, Laumola EL, Poijes N, Johansson M, Ericson AC. Assessment of the effects of changes in body temperature on cardiac electrophysiology in anaesthetised guinea pigs. J Pharmacol Toxicol Methods 2011; 65:1-7. [PMID: 22178983 DOI: 10.1016/j.vascn.2011.11.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2011] [Revised: 11/28/2011] [Accepted: 11/29/2011] [Indexed: 12/31/2022]
Abstract
INTRODUCTION Anaesthetised guinea pigs are commonly used within Safety Pharmacology to evaluate drug effects on cardiac electrophysiology. However, anesthesia compromises the ability to thermoregulate, which can be further challenged when more invasive surgery is required. As anaesthetised animals are often used when screening for cardiotoxicity, thereby influencing go/no-go decisions, we wanted to quantify the impact of small temperature changes on the recorded electrophysiological parameters. METHODS Male guinea pigs were anaesthetised by pentobarbital, placed on a pre-heated table and a rectal thermistor inserted for monitoring of body temperature. After intubation animals were vagotomised and β-blocked, and lead II ECG needle electrodes attached. Following thoracotomy an atrial pacing electrode was attached and a suction MAP electrode positioned on the ventricular epicardium. In control animals temperature was kept constant (38.1±0.1°C) over the duration of the experiment. Animals in one group were slowly warmed to 41.9°C by a heating plate and a heating lamp, and in another group slowly cooled to 34.4°C by turning off all heating equipment. MAP duration at 90% repolarisation (MAPD90), AV conduction, ECG and body temperature were recorded during cardiac pacing every 5min up to 50min. RESULTS No time-dependent changes were seen in the control group. In contrast, a linear correlation was found between changes in body temperature and MAPD90, AV conduction, QTc and QRS intervals. For each degree temperature fell below 38°C MAPD90 was prolonged by 6.1ms, and for each degree above 38°C MAPD90 was shortened by 5.3ms. Corresponding changes were seen for QTc interval and AV conduction time, while effects on the QRS interval were smaller. DISCUSSION The data highlights the importance of carefully controlling body temperature when performing electrophysiological recordings in laboratory animals. A change by a single degree can affect electrophysiological parameters by 5-10%, thus increasing the risk for a false positive or negative interpretation of cardiotoxicity.
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Affiliation(s)
- Jens Kågström
- Safety Pharmacology, Safety Assessment, AstraZeneca R&D Södertälje, S-151 85 Södertälje, Sweden.
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Supplemental Studies for Cardiovascular Risk Assessment in Safety Pharmacology: A Critical Overview. Cardiovasc Toxicol 2011; 11:285-307. [DOI: 10.1007/s12012-011-9133-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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Redfern WS, Valentin JP. Trends in safety pharmacology: Posters presented at the annual meetings of the Safety Pharmacology Society 2001–2010. J Pharmacol Toxicol Methods 2011; 64:102-10. [DOI: 10.1016/j.vascn.2011.05.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2011] [Accepted: 05/13/2011] [Indexed: 01/01/2023]
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Clobutinol delays ventricular repolarization in the guinea pig heart: comparison with cardiac effects of HERG K+ channel inhibitor E-4031. J Cardiovasc Pharmacol 2010; 54:552-9. [PMID: 19770670 DOI: 10.1097/fjc.0b013e3181bfb17c] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Clobutinol has been clinically reported to induce long QT syndrome. To clarify its cardiac electrophysiological properties, we compared effects of clobutinol on the isolated myocardium and anesthetized guinea pig heart with those of a hERG K channel blocker, E-4031. In isolated guinea pig ventricular tissues, clobutinol (3 microM) as well as E-4031 (10-100 nM) prolonged the action potential duration without affecting maximum upstroke velocity, but no further prolongation was observed after application of 30 microM clobutinol. In anesthetized closed-chest guinea pigs, clobutinol (1 and 10 mg/kg, intravenously) and E-4031 (0.01 and 1 mg/kg, intravenously) prolonged the QT interval and duration of the monophasic action potential (MAP) in a dose-dependent manner and at the same time increased the beat-to-beat variability of the MAP duration and reversed use-dependent prolongation of the MAP duration and triangulation of the MAP configuration. These results suggest that clobutinol delayed the ventricular repolarization and increased the proarrhythmic parameters linked to the hERG K channel inhibitor-induced torsade de pointes arrhythmias.
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Hardy MEL, Pollard CE, Small BG, Bridgland-Taylor M, Woods AJ, Valentin JP, Abi-Gerges N. Validation of a voltage-sensitive dye (di-4-ANEPPS)-based method for assessing drug-induced delayed repolarisation in beagle dog left ventricular midmyocardial myocytes. J Pharmacol Toxicol Methods 2009; 60:94-106. [PMID: 19414070 DOI: 10.1016/j.vascn.2009.03.005] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2009] [Accepted: 03/10/2009] [Indexed: 10/20/2022]
Abstract
INTRODUCTION Evaluation of drug candidates in in-vitro assays of action potential duration (APD) is one component of preclinical safety assessment. Current assays are limited by technically-demanding, time-consuming electrophysiological methods. This study aimed to assess whether a voltage-sensitive dye-based assay could be used instead. METHODS Optical APs were recorded using di-4-ANEPPS in electrically field stimulated beagle left ventricular midmyocardial myocytes (LVMMs). Pharmacological properties of di-4-ANEPPS on the main cardiac ion channels that shape the ventricular AP were investigated using IonWorks and conventional electrophysiology. Effects of 9 reference drugs (dofetilide, E4031, D-sotalol, ATXII, cisapride, terfenadine, alfuzosin, diltiazem and pinacidil) with known APD-modulating effects were assessed on optically measured APD at 1 Hz. RESULTS Under optimum conditions, 0.1 microM di-4-ANEPPS could be used to monitor APs paced at 1 Hz during nine, 5 s exposures without altering APD. di-4-ANEPPS had no effect on either hI(ERG), hI(Na), hI(Ks) and hI(to) currents in transfected CHO cells (up to 10 microM) or I(Ca,L) current in LVMMs (at 16 microM). di-4-ANEPPS had no effect on APs recorded with microelectrodes at 1 or 0.5 Hz over a period of 30 min di-4-ANEPPS displayed the sensitivity to record changes in optically measured APD in response to altered pacing frequencies and sequential vehicle additions did not affect the optically measured APD. APD data obtained with 9 reference drugs were as expected except (i) D-sotalol-induced increases in duration were smaller than those caused by other I(Kr) blockers and (ii) increases in APD were not detected using low concentrations of terfenadine. DISCUSSION Early in drug discovery, the di-4-ANEPPS-based method can reliably be used to assess drug effects on APD as part of a cardiac risk assessment strategy.
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Affiliation(s)
- Matthew E L Hardy
- Safety Pharmacology Department, Safety Assessment UK, AstraZeneca R&D, Alderley Park, Macclesfield, Cheshire SK104TG, UK
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Sakaguchi Y, Takahara A, Nakamura Y, Akie Y, Sugiyama A. Halothane-Anaesthetized, Closed-Chest, Guinea-Pig Model for Assessment of Drug-Induced QT-Interval Prolongation. Basic Clin Pharmacol Toxicol 2009; 104:43-8. [DOI: 10.1111/j.1742-7843.2008.00312.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Pugsley MK, Authier S, Curtis MJ. Principles of safety pharmacology. Br J Pharmacol 2008; 154:1382-99. [PMID: 18604233 PMCID: PMC2492105 DOI: 10.1038/bjp.2008.280] [Citation(s) in RCA: 146] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2008] [Revised: 06/09/2008] [Accepted: 06/12/2008] [Indexed: 11/09/2022] Open
Abstract
Safety Pharmacology is a rapidly developing discipline that uses the basic principles of pharmacology in a regulatory-driven process to generate data to inform risk/benefit assessment. The aim of Safety Pharmacology is to characterize the pharmacodynamic/pharmacokinetic (PK/PD) relationship of a drug's adverse effects using continuously evolving methodology. Unlike toxicology, Safety Pharmacology includes within its remit a regulatory requirement to predict the risk of rare lethal events. This gives Safety Pharmacology its unique character. The key issues for Safety Pharmacology are detection of an adverse effect liability, projection of the data into safety margin calculation and finally clinical safety monitoring. This article sets out to explain the drivers for Safety Pharmacology so that the wider pharmacology community is better placed to understand the discipline. It concludes with a summary of principles that may help inform future resolution of unmet needs (especially establishing model validation for accurate risk assessment). Subsequent articles in this issue of the journal address specific aspects of Safety Pharmacology to explore the issues of model choice, the burden of proof and to highlight areas of intensive activity (such as testing for drug-induced rare event liability, and the challenge of testing the safety of so-called biologics (antibodies, gene therapy and so on.).
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Affiliation(s)
- M K Pugsley
- Department of Toxicology & Pathology, Global Preclinical Development, Johnson & Johnson Pharmaceutical Research & Development Raritan, NJ, USA
| | - S Authier
- LAB Research Inc., 445 Armand Frappier, Laval Quebec, Canada
| | - M J Curtis
- Cardiovascular Division St Thomas' Hospital, King's College London, London, UK
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