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BARTAKOVA A, NOVAKOVA M, STRACINA T. Anesthetized guinea pig as a model for drug testing. Physiol Res 2022; 71:S211-S218. [PMID: 36647909 PMCID: PMC9906665 DOI: 10.33549/physiolres.934994] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Based on the World Health Organization statistics, cardiovascular diseases represent the major cause of death worldwide. Although a wide range of treatment approaches and pharmaceuticals is available, the therapy is often not effective enough and therefore health risks for the patient persist. Thus, it is still essential to test new drug candidates for the treatment of various pathophysiological conditions related to cardiovascular system. In vivo models represent indispensable part of preclinical testing of such substances. Anesthetized guinea pig as a whole-body model allows to evaluate complex reactions of cardiovascular system to tested substance. Moreover, action potential of guinea pig cardiomyocyte is quite comparable to that of human. Hence, the results from this model are then quite well translatable to clinical medicine. Aim of this paper was to summarize the methodology of this model, including its advantages and/or limitations and risks, based on the effects of two substances with adrenergic activity on the ECG parameters. The model of anesthetized guinea pig proved to be valuable and suitable for testing of drugs with cardiovascular effects.
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Affiliation(s)
- Anna BARTAKOVA
- Department of Physiology, Faculty of Medicine, Masaryk University, Brno, Czech Republic
| | - Marie NOVAKOVA
- Department of Physiology, Faculty of Medicine, Masaryk University, Brno, Czech Republic
| | - Tibor STRACINA
- Department of Physiology, Faculty of Medicine, Masaryk University, Brno, Czech Republic
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Lu HR, Kreir M, Karel VA, Tekle F, Geyskens D, Teisman A, Gallacher DJ. Identifying Acute Cardiac Hazard in Early Drug Discovery Using a Calcium Transient High-Throughput Assay in Human-Induced Pluripotent Stem Cell-Derived Cardiomyocytes. Front Physiol 2022; 13:838435. [PMID: 35547580 PMCID: PMC9083324 DOI: 10.3389/fphys.2022.838435] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Accepted: 03/21/2022] [Indexed: 11/13/2022] Open
Abstract
Introduction: Early identification of cardiac risk is essential for reducing late-stage attrition in drug development. We adapted the previously published cardiac hazard risk-scoring system using a calcium transient assay in human stem cell-derived CMs for the identification of cardiac risks recorded from the new hiPSC-CM line and investigated its predictivity and translational value based on the screening of a large number of reference and proprietary compounds. Methods: Evaluation of 55 reference drugs provided the translation of various pharmacological effects into a single hazard label (no, low, high, or very high hazard) using a Ca2+-sensitive fluorescent dye assay recorded by -by FDSS/µCell Functional Drug Screening System (Hamamatsu on hiPSC-CM line (FCDI iCell Cardiomyocytes2). Results: Application of the adapted hazard scoring system in the Ca2+ transient assay, using a second hiPS-CM line, provided comparable scoring results and predictivity of hazard, to the previously published scoring approach, with different pharmacological drug classes, as well as screening new chemical entities (NCE's) using a single hazard label from four different scoring levels (no, low, high, or very high hazard). The scoring system results also showed minimal variability across three different lots of hiPSC-CMs, indicating good reproducibility of the cell line. The predictivity values (sensitivity and specificity) for drug-induced acute cardiac risk for QT-interval prolongation and Torsade de pointes (TdPs) were >95% and statistical modeling confirmed the prediction of proarrhythmic risk. The outcomes of the NCEs also showed consistency with findings in other well-established in vitro and in vivo cardiac risk assays. Conclusion: Evaluation of a large list of reference compounds and internal NCEs has confirmed the applicability of the adaptations made to the previously published novel scoring system for the hiPSC-CMs. The validation also established the predictivity for drug-induced cardiac risks with good translation to other established preclinical in vitro and in vivo assays, confirming the application of this novel scoring system in different stem cell-CM lines for early cardiac hazard identification.
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Affiliation(s)
- Hua Rong Lu
- Global Safety Pharmacology, Predictive, Investigative and Translational Toxicology, Nonclinical Safety, Beerse, Belgium
| | - Mohamed Kreir
- Global Safety Pharmacology, Predictive, Investigative and Translational Toxicology, Nonclinical Safety, Beerse, Belgium
| | - Van Ammel Karel
- Global Safety Pharmacology, Predictive, Investigative and Translational Toxicology, Nonclinical Safety, Beerse, Belgium
| | - Fetene Tekle
- Discovery and Nonclinical Safety Statistics, Statistics and Decision Sciences, Quantitative Sciences, Janssen R&D, A Division of Janssen Pharmaceutica NV, Beerse, Belgium
| | - Danny Geyskens
- Global Safety Pharmacology, Predictive, Investigative and Translational Toxicology, Nonclinical Safety, Beerse, Belgium
| | - Ard Teisman
- Global Safety Pharmacology, Predictive, Investigative and Translational Toxicology, Nonclinical Safety, Beerse, Belgium
| | - David J Gallacher
- Global Safety Pharmacology, Predictive, Investigative and Translational Toxicology, Nonclinical Safety, Beerse, Belgium
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Skinner M, Hale E, Ceuppens P, Pollard C. Differentiating multichannel block on the guinea pig ECG: Use of T peak-T end and J-T peak. J Pharmacol Toxicol Methods 2021; 111:107085. [PMID: 34182121 DOI: 10.1016/j.vascn.2021.107085] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 05/14/2021] [Accepted: 06/07/2021] [Indexed: 10/21/2022]
Abstract
INTRODUCTION The anaesthetised guinea pig is a well characterised assay for early assessment of drug effects on ventricular repolarisation and risk of Torsade de Pointes (TdP). We assessed whether a selective hERG blocker with known TdP risk could be differentiated from lower risk, balanced ion channel blockers in the guinea pig, using corrected QT (QTc) interval alongside novel electrocardiogram (ECG) biomarkers J-Tpeakc and Tpeak-Tend. Effects were compared with previous clinical investigations at similar plasma concentrations and with another index of TdP risk, the electromechanical window (EMW). METHODS Twenty-two Dunkin Hartley guinea pigs anaesthetised with sodium pentobarbitone were instrumented for haemodynamic measurement and ECG recording. Three ascending doses of vehicle (n = 6), dofetilide (2, 6 or 20 μg/kg; n = 7), ranolazine (2, 6 or 20 mg/kg; n = 5) or verapamil (0.1, 0.3 or 1.0 mg/kg; n = 4) were administered intravenously. RESULTS As reported in previous clinical studies, dofetilide induced dose-dependent increases in QTc interval, with increases in both J-TpeakC or Tpeak-Tend, while verapamil caused no significant increase in QTc interval, J-TpeakC or Tpeak-Tend. Ranolazine caused dose-dependent increases in QTc interval and corrected J-Tpeakc, but had no effect on Tpeak-Tend, which is in contrast to the effects reported in humans at similar concentrations. Only dofetilide caused a clear, dose-related decrease in the EMW. DISCUSSION These findings suggest that measurements of J-Tpeakc and Tpeak-Tend in addition to QT interval, may help differentiate pure hERG channel blockers with high risk of TdP from lower risk, multichannel blockers.
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Affiliation(s)
- Matt Skinner
- Vivonics Preclinical Ltd, BioCity Nottingham, Pennyfoot Street, Nottingham NG1 1GF, UK.
| | - Ed Hale
- Vivonics Preclinical Ltd, BioCity Nottingham, Pennyfoot Street, Nottingham NG1 1GF, UK.
| | - Peter Ceuppens
- Inferstats Consulting Ltd, Biohub at Alderley Park, Cheshire SK10 4TG, UK.
| | - Chris Pollard
- Vivonics Preclinical Ltd, BioCity Nottingham, Pennyfoot Street, Nottingham NG1 1GF, UK.
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Tolbert D, Gordon J, Harris S, Walzer M, Bekersky I, Reid S. A Thorough QT/QTc Study of Clobazam in Healthy Volunteers. Clin Ther 2017; 39:2073-2086. [DOI: 10.1016/j.clinthera.2017.08.020] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Revised: 08/14/2017] [Accepted: 08/31/2017] [Indexed: 10/18/2022]
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Discovery of a potent and selective ROMK inhibitor with improved pharmacokinetic properties based on an octahydropyrazino[2,1-c][1,4]oxazine scaffold. Bioorg Med Chem Lett 2016; 26:5695-5702. [DOI: 10.1016/j.bmcl.2016.10.064] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2016] [Revised: 10/19/2016] [Accepted: 10/21/2016] [Indexed: 11/17/2022]
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Xie S, Jia Y, Liu A, Dai R, Huang L. Hypaconitine-induced QT prolongation mediated through inhibition of KCNH2 (hERG) potassium channels in conscious dogs. JOURNAL OF ETHNOPHARMACOLOGY 2015; 166:375-379. [PMID: 25800797 DOI: 10.1016/j.jep.2015.03.023] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2014] [Revised: 01/15/2015] [Accepted: 03/09/2015] [Indexed: 06/04/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Hypaconitine is one of the main aconitum alkaloids in traditional Chinese medicines prepared with herbs from the genus Acotinum. These herbs are widely used for the treatment of cardiac insufficiency and arrhythmias. However, Acotinum alkaloids are known for their toxicity as well as their pharmacological activity, especially cardiotoxicity including QT prolongation, and the mechanism of this toxicity is not clear. MATERIAL AND METHODS In this study, hypaconitine was administered orally to conscious Beagle dogs, and electrocardiograms were recorded by telemetry. Pharmacokinetic studies (6h) were conducted to evaluate the relationship between QT prolongation and exposure level. HEK293 cells stably transfected with KCNH2 (hERG) cDNA were used to examine the effects of hypaconitine on the KCNH2 channel by using the manual patch clamp technique. RESULTS In the conscious dogs, all doses of hypaconitine induced QTcV (QT interval corrected according to the Van de Water formula) prolongation by more than 23% (67ms) of control in a dose-dependent manner. The maximum QTcV prolongation was observed at 2h after dosing. Maximum prolongation percentages were plotted against plasma concentrations of hypaconitine and showed a strong correlation (R(2)=0.789). In the in vitro study in HEK293 cells, hypaconitine inhibited the KCNH2 currents in a concentration-dependent manner with an IC50 of 8.1nM. CONCLUSION These data suggest that hypaconitine inhibits KCNH2 potassium channels and this effect might be the molecular mechanism underlying QT prolongation in conscious dogs.
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Affiliation(s)
- Shuilin Xie
- School of Bioscience and Bioengineering, South China University of Technology, Guangzhou 510006, China
| | - Ying Jia
- School of Bioscience and Bioengineering, South China University of Technology, Guangzhou 510006, China
| | - Aiming Liu
- Medical School of Ningbo University, Ningbo 315211, China
| | - Renke Dai
- School of Bioscience and Bioengineering, South China University of Technology, Guangzhou 510006, China
| | - Lizhen Huang
- School of Bioscience and Bioengineering, South China University of Technology, Guangzhou 510006, China.
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Chain ASY, Sturkenboom MCJM, Danhof M, Della Pasqua OE. Establishing in vitro to clinical correlations in the evaluation of cardiovascular safety pharmacology. DRUG DISCOVERY TODAY. TECHNOLOGIES 2013; 10:e373-e383. [PMID: 24050134 DOI: 10.1016/j.ddtec.2012.07.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Preclinical studies are vital in establishing the efficacy and safety of a new chemical entity (NCE) in humans. To deliver meaningful information, experiments have to be well defined and provide outcome that is relevant and translatable to humans. This review briefly surveys the various preclinical experiments that are frequently conducted to assess drug effects on cardiac conductivity in early drug development. We examine the different approaches used to establish correlations between non-clinical and clinical settings and discuss their value in the evaluation of cardiovascular risk.
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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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Park MJ, Lee KR, Shin DS, Chun HS, Kim CH, Ahn SH, Bae MA. Predicted drug-induced bradycardia related cardio toxicity using a zebrafish in vivo model is highly correlated with results from in vitro tests. Toxicol Lett 2013; 216:9-15. [DOI: 10.1016/j.toxlet.2012.10.018] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2012] [Revised: 10/26/2012] [Accepted: 10/29/2012] [Indexed: 11/30/2022]
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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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Negative electro-mechanical windows are required for drug-induced Torsades de Pointes in the anesthetized guinea pig. J Pharmacol Toxicol Methods 2012; 66:125-34. [DOI: 10.1016/j.vascn.2012.03.007] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2012] [Revised: 03/13/2012] [Accepted: 03/29/2012] [Indexed: 11/17/2022]
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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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Mooney L, Marks L, Philp KL, Skinner M, Coker SJ, Currie S. Optimising conditions for studying the acute effects of drugs on indices of cardiac contractility and on haemodynamics in anaesthetized guinea pigs. J Pharmacol Toxicol Methods 2012; 66:43-51. [PMID: 22659057 DOI: 10.1016/j.vascn.2012.05.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2012] [Revised: 04/19/2012] [Accepted: 05/23/2012] [Indexed: 11/30/2022]
Abstract
INTRODUCTION Detecting adverse effects of drugs on cardiac contractility is becoming a priority in pre-clinical safety pharmacology. The aim of this work was to optimise conditions and explore the potential of using the anaesthetized guinea pig as an in vivo model. METHODS Guinea pigs were anaesthetized with Hypnorm/Hypnovel, isoflurane, pentobarbital or fentanyl/pentobarbital. The electrocardiogram (ECG), heart rate, arterial blood pressure and indices of cardiac contractility were recorded. In further experiments in fentanyl/pentobarbital anaesthetized guinea pigs the influence of bilateral versus unilateral carotid artery occlusion on haemodynamic responses was investigated and the effects of inotropic drugs on left ventricular (LV) dP/dt(max) and the QA interval were determined. RESULTS Pentobarbital, given alone or after fentanyl, provided suitable anaesthesia for these experiments. Bilateral carotid artery occlusion did not alter heart rate or arterial blood pressure responses to isoprenaline or angiotensin II. Isoprenaline and ouabain increased LVdP/dt(max) and decreased the QA interval whereas verapamil had opposite effects and strong inverse correlations between LVdP/dt(max) and the QA interval were found. DISCUSSION Conditions can be optimised to allow the pentobarbital-anaesthetized guinea pig to be used for simultaneous measurement of the effects of drugs on the ECG, haemodynamics and indices of cardiac contractility. The use of this small animal model in early pre-clinical safety pharmacology should contribute to improvements in detecting unwanted actions on the heart during the drug development process.
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Affiliation(s)
- Laura Mooney
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, G4 0RE, UK
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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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Increased cardiac risk in concomitant methadone and diazepam treatment: pharmacodynamic interactions in cardiac ion channels. J Cardiovasc Pharmacol 2011; 56:420-30. [PMID: 20930594 DOI: 10.1097/fjc.0b013e3181f1d21b] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Methadone, a synthetic opioid for treatment of chronic pain and withdrawal from opioid dependence, has been linked to QT prolongation, potentially fatal torsades de pointes, and sudden cardiac death. Concomitant use of diazepam or other benzodiazepines in methadone maintenance treatment can increase the risk of sudden death. Therefore, we determined the effects of methadone and diazepam singly and in combination on cardiac action potentials (APs) and on the major ion channels responsible for cardiac repolarization. Using patch clamp recording in human stem cell-derived cardiomyocytes and stably transfected mammalian cells, we found that methadone produced concentration-dependent AP prolongation and ion channel block at low micromolar concentrations: hERG (IC50 = 1.7 μM), hNav1.5 (11.2 μM tonic block; 5.5 μM phasic block), and hCav1.2 (26.7 μM tonic block; 7.7 μM phasic block). Methadone was less potent in hKv4.3/hKChIP2.2 (IC50 = 39.0 μM) and hKvLQT1/hminK (53.3 μM). In contrast, diazepam blocked channels only at much higher concentrations and had no effect on AP duration at 1 μM. However, coadministration of 1-μM diazepam with methadone caused a statistically significant increase in AP duration and a 4-fold attenuation of hNav1.5 block (IC50 values were 44.2 μM and 26.6 μM, respectively, for tonic and phasic block), with no significant effect on methadone-induced block of hERG, hCav1.2, hKv4.3/hKChIP2.2, and hKvLQT1/hminK channels. Thus, although diazepam alone does not prolong the QT interval, the relief of methadone-induced Na channel block may leave hERG K channel block uncompensated, thereby increasing cardiac risk.
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Testai L, Cecchetti V, Sabatini S, Martelli A, Breschi MC, Calderone V. Effects of KATPopeners on the QT prolongation induced by HERG-blocking drugs in guinea-pigs. J Pharm Pharmacol 2010. [DOI: 10.1211/jpp.62.07.0014] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
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Calderone V, Testai L, Martinotti E, Del Tacca M, Breschi MC. Drug-induced block of cardiac HERG potassium channels and development of torsade de pointes arrhythmias: the case of antipsychotics. J Pharm Pharmacol 2010; 57:151-61. [PMID: 15720777 DOI: 10.1211/0022357055272] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
Abstract
The prolongation of the cardiac repolarization process, a result of the blocking of the Human Ether-a-go-go Related Gene potassium channel, is an undesired accessory property shared by many pharmacological classes of non-cardiovascular drugs. Often the delayed cardiac repolarization process can be identified by a prolongation of the QT interval of the electrocardiograph. In these conditions, premature action potentials can trigger a dangerous polymorphic ventricular tachyarrhythmia, known as torsade de pointes, which occasionally can result in lethal ventricular fibrillation. In this work, brief descriptions of the electrophysiological basis of torsade de pointes and of the several pharmacological classes of torsadogenic drugs are given. Attention is focused on antipsychotics, with a deeper overview on the experimental and clinical reports about their torsadogenic properties.
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Affiliation(s)
- Vincenzo Calderone
- Dipartimento di Psichiatria, Neurobiologia, Farmacologia e Biotecnologie, Università degli Studi di Pisa, Via Bonanno 6, I-56126, Pisa, Italy.
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Crumb W, Benyamina A, Arbus C, Thomas GP, Garay RP, Hameg A. Cyamemazine metabolites: effects on human cardiac ion channels in-vitro and on the QTc interval in guinea pigs. J Pharm Pharmacol 2010. [DOI: 10.1211/jpp.60.11.0012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
Abstract
Monodesmethyl cyamemazine and cyamemazine sulfoxide, the two main metabolites of the antipsychotic and anxiolytic phenothiazine cyamemazine, were investigated for their effects on the human ether-à-go-go related gene (hERG) channel expressed in HEK 293 cells and on native INa, ICa, Ito, Isus or IK1 of human atrial myocytes. Additionally, cyamemazine metabolites were compared with terfenadine for their effects on the QT interval in anaesthetized guinea pigs. Monodesmethyl cyamemazine and cyamemazine sulfoxide reduced hERG current amplitude, with IC50 values of 0.70 and 1.53 μM, respectively. By contrast, at a concentration of 1 μM, cyamemazine metabolites failed to significantly affect INa, Ito, Isus or IK1 current amplitudes. Cyamemazine sulfoxide had no effect on ICa at 1 μM, while at this concentration, monodesmethyl cyamemazine only slightly (17%), albeit significantly, inhibited ICa current. Finally, cyamemazine metabolites (5 mg kg−1 i.v.) were unable to significantly prolong QTc values in the guinea pig. Conversely, terfenadine (5 mg kg−1 i.v.) significantly increased QTc values. In conclusion, cyamemazine metabolite concentrations required to inhibit hERG current substantially exceed those necessary to achieve therapeutic activity of the parent compound in humans. Moreover, cyamemazine metabolites, in contrast to terfenadine, do not delay cardiac repolarization in the anaesthetized guinea pig. These non-clinical findings explain the excellent cardiac safety records of cyamemazine during its 30 years of extensive therapeutic use.
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Affiliation(s)
| | - Amine Benyamina
- INSERM U669, Hôpital Universitaire Paul-Brousse, Villejuif, France
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Tabo M, Komatsu R, Isobe T, Honda M, Yamada Y, Kimura K. Accurate detection of drug-induced delayed ventricular repolarization with a suitable correction formula in Langendorff guinea pig heart. J Toxicol Sci 2010; 35:687-98. [DOI: 10.2131/jts.35.687] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Affiliation(s)
- Mitsuyasu Tabo
- Safety Assessment Department, Chugai Pharmaceutical Co., Ltd
| | - Ryuichi Komatsu
- Safety Assessment Department, Chugai Pharmaceutical Co., Ltd
| | - Takehito Isobe
- Safety Assessment Department, Chugai Pharmaceutical Co., Ltd
| | - Masaki Honda
- Safety Assessment Department, Chugai Pharmaceutical Co., Ltd
| | - Yuichiro Yamada
- Safety Assessment Department, Chugai Pharmaceutical Co., Ltd
| | - Kazuya Kimura
- Safety Assessment Department, Chugai Pharmaceutical Co., Ltd
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Aslanian R, Piwinski JJ, Zhu X, Priestley T, Sorota S, Du XY, Zhang XS, McLeod RL, West RE, Williams SM, Hey JA. Structural determinants for histamine H1 affinity, hERG affinity and QTc prolongation in a series of terfenadine analogs. Bioorg Med Chem Lett 2009; 19:5043-7. [DOI: 10.1016/j.bmcl.2009.07.047] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2009] [Revised: 07/06/2009] [Accepted: 07/08/2009] [Indexed: 01/08/2023]
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Coi A, Massarelli I, Testai L, Calderone V, Bianucci AM. Identification of “toxicophoric” features for predicting drug-induced QT interval prolongation. Eur J Med Chem 2008; 43:2479-88. [DOI: 10.1016/j.ejmech.2007.12.025] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2007] [Revised: 12/07/2007] [Accepted: 12/11/2007] [Indexed: 11/26/2022]
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Predicting QT prolongation in humans during early drug development using hERG inhibition and an anaesthetized guinea-pig model. Br J Pharmacol 2008; 154:1446-56. [PMID: 18587422 PMCID: PMC2442905 DOI: 10.1038/bjp.2008.267] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Background and purpose: Drug-induced prolongation of the QT interval can lead to torsade de pointes, a life-threatening ventricular arrhythmia. Finding appropriate assays from among the plethora of options available to predict reliably this serious adverse effect in humans remains a challenging issue for the discovery and development of drugs. The purpose of the present study was to develop and verify a reliable and relatively simple approach for assessing, during preclinical development, the propensity of drugs to prolong the QT interval in humans. Experimental approach: Sixteen marketed drugs from various pharmacological classes with a known incidence—or lack thereof—of QT prolongation in humans were examined in hERG (human ether a-go-go-related gene) patch-clamp assay and an anaesthetized guinea-pig assay for QT prolongation using specific protocols. Drug concentrations in perfusates from hERG assays and plasma samples from guinea-pigs were determined using liquid chromatography-mass spectrometry. Key results: Various pharmacological agents that inhibit hERG currents prolong the QT interval in anaesthetized guinea-pigs in a manner similar to that seen in humans and at comparable drug exposures. Several compounds not associated with QT prolongation in humans failed to prolong the QT interval in this model. Conclusions and implications: Analysis of hERG inhibitory potency in conjunction with drug exposures and QT interval measurements in anaesthetized guinea-pigs can reliably predict, during preclinical drug development, the risk of human QT prolongation. A strategy is proposed for mitigating the risk of QT prolongation of new chemical entities during early lead optimization.
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Michael G, Kane KA, Coker SJ. Adrenaline reveals the torsadogenic effect of combined blockade of potassium channels in anaesthetized guinea pigs. Br J Pharmacol 2008; 154:1414-26. [PMID: 18493252 DOI: 10.1038/bjp.2008.169] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND AND PURPOSE Torsade de pointes (TdP) can be induced in several species by a reduction in cardiac repolarizing capacity. The aim of this study was to assess whether combined I(Kr) and I(Ks) blockade could induce TdP in anaesthetized guinea pigs and whether short-term variability (STV) or triangulation of action potentials could predict TdP. EXPERIMENTAL APPROACH Experiments were performed in open-chest, pentobarbital-anaesthetized, adrenaline-stimulated male Dunkin Hartley guinea pigs, which received three consecutive i.v. infusions of either vehicle, the I(Kr) blocker E-4031 (3, 10 and 30 nmol kg(-1) min(-1)), the I(Ks) blocker HMR1556 (75, 250, 750 nmol kg(-1) min(-1)) or E-4031 and HMR1556 combined. Phenylephrine-stimulated guinea pigs were also treated with the K(+) channel blockers in combination. Arterial blood pressure, ECGs and epicardial monophasic action potential (MAP) were recorded. KEY RESULTS TdP was observed in 75% of adrenaline-stimulated guinea pigs given the K(+) channel blockers in combination, but was not observed in guinea pigs treated with either I(K) blocker alone, or in phenylephrine-stimulated guinea pigs. Salvos and ventricular tachycardia occurred with adrenaline but not with phenylephrine. No changes in STV or triangulation of the MAP signals were observed before TdP. CONCLUSIONS AND IMPLICATIONS Combined blockade of both I(Kr) and I(Ks) plus the addition of adrenaline were required to induce TdP in anaesthetized guinea pigs. This suggests that there must be sufficient depletion of repolarization reserve and an appropriate trigger for TdP to occur.
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Affiliation(s)
- G Michael
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, UK
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Tabo M, Kimura K, Ito S. Monophasic action potential in anaesthetized guinea pigs as a biomarker for prediction of liability for drug-induced delayed ventricular repolarization. J Pharmacol Toxicol Methods 2007; 55:254-61. [PMID: 17229580 DOI: 10.1016/j.vascn.2006.11.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2006] [Accepted: 11/20/2006] [Indexed: 12/01/2022]
Abstract
INTRODUCTION Drug-induced QT interval prolongation has been one of the critical issues for developing new chemical entities and pharmaceutical companies need to evaluate the risk early in the development stage. At such stage, guinea pigs are appropriate due to their small size requiring only small amounts of test drugs. The purpose of this study was to determine the utility of guinea pig monophasic action potential (MAP) using 12 reference drugs in order to clarify prediction of the QT interval prolonging risk. METHODS Male guinea pigs were anaesthetized with pentobarbital (40 mg/kg, i.p.). Parameters analyzed were epicardial MAP duration (MAP(90)) at sinus rhythm (MAP(90(sinus))) and MAP(90) during atrial pacing (MAP(90(pacing))). Test drugs were administered to animals intravenously and cumulatively. RESULTS Vehicle control did not affect the parameters tested. All 8 QT-prolonging drugs prolonged MAP(90(sinus)) and MAP(90(pacing)) dose-dependently, whereas all 4 non-QT-prolonging drugs showed no or very slight prolongations of these MAP(90) parameters. Rank order potency of MAP(90(pacing)) prolongations by the QT-prolonging drugs tended to correspond to clinical plasma concentrations associated with QT interval prolongations or Torsades de Pointes but showed less of a link with hERG inhibition activities. CONCLUSION The present study demonstrates that the MAP model using anaesthetized guinea pigs could predict the liability of drugs for QT interval prolongation with high accuracy. QT assessment using the combination of the hERG assay with high sensitivity and the current in vivo assay would be desirable for early risk assessment within drug development.
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Affiliation(s)
- Mitsuyasu Tabo
- Safety Assessment Department, Chugai Pharmaceutical Co., Ltd., Shizuoka 412-8513, Japan.
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Abstract
The hERG (human ether-à-go-go-related gene) potassium channel has elicited intense scientific interest due to its counter-intuitive kinetics and its association with arrhythmia and sudden death. hERG blockade is involved in both antiarrhythmic pharmacotherapy and the pathogenesis of familial and acquired long QT syndrome (LQTS). Short QT syndrome (SQTS), muscular atrophy and many forms of cancer have also been associated with hERG as a target. Molecular models of both the channel and its blocker pharmacophores exist, revealing methods to design hERG liability out of potential drug molecules. Future developments will synthesise preclinical data on hERG with other criteria to determine net arrhythmogenic risk. Also, the molecular actions of hERG and its genetics will be elucidated in detail to allow clinical risk reduction.
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Affiliation(s)
- Harry J Witchel
- University of Bristol, School of Medical Sciences, Department of Physiology, Bristol, BS8 1TD, UK.
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Schmitt MW, Von Landenberg F, Poth H, Wimmer E, Goddemeier T, Cavero I. Simple-to-use, reference criteria for revealing drug-induced QT interval prolongation in conscious dogs. Eur J Pharmacol 2007; 554:46-52. [PMID: 17112506 DOI: 10.1016/j.ejphar.2006.09.056] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2006] [Revised: 09/19/2006] [Accepted: 09/22/2006] [Indexed: 11/23/2022]
Abstract
Electrocardiogram (ECG) QT interval prolongation produced by drugs in certain animal models is currently believed to be predictive of cardiac proarrhythmic effects in humans. For this reason, nonclinical assessment of the effects of novel drugs on cardiac repolarization is a regulatory prerequisite for progressing such agents to clinical evaluation. The present investigation was carried out to develop reliable, simple-to-use reference criteria for identifying individual animals as responders to drugs that prolong the QT interval. ECG were recorded for 30 s at 0 (8 am), 2, 4, 6 and 24 h in 6 trained, conscious, beagle dogs during 5 control experimental sessions. QT intervals were measured and corrected for heart rate by applying the Van de Water algorithm (QTc). The maximal (QTc(max)) and minimal (QTc(min)) values of QTc observed in each of the five control recording sessions were noted. Two reference (R) criteria were used to designate an individual animal as a responder to drug treatment: 1) QTc(maxR) which was obtained by adding 10 ms to the largest value of QTc(max) observed during the five control recording sessions and 2) (QTc(max)-QTc(min))(maxR) which was obtained by increasing by 50% the largest of the (QTc(max)-QTc(min)) values [(QTc(max)-QTc(min))(max)] observed in the 5 control recording sessions. The sensitivity and reliability of these criteria were tested by determining QTc intervals before and 2, 4, 6 and 24 h after placebo or quinidine (200, 400 and 800 mg p.o. per animal). The reference values of QTc(maxR) and (QTc(max)-QTc(min))(maxR) for the various dogs ranged from 246 to 270 ms and from 15 to 19.5 ms, respectively. The number of dogs responding to treatment (T: quinidine at 200, 400 and 800 mg, p.o. per animal) with a QTc(maxT) and/or a (QTc(max)-QTc(min))(maxT) equal to or greater than the respective reference values was, respectively, 1/6, 3/6 and 5/6 dogs. Additionally, the number of responders correlated well with the concentration of free quinidine in the plasma. In conclusion, this investigation succeeded in establishing reliable, reference criteria for individual dogs despite the intrinsic daily variation of QTc interval. The application of these criteria allowed identifying individual animals responding to quinidine with delayed cardiac repolarization.
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Affiliation(s)
- Michael W Schmitt
- MerckKGaA, Pharma Ethicals, Research and Development, D-64271 Darmstadt, Germany.
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Testai L, Breschi MC, Martinotti E, Calderone V. QT prolongation in guinea pigs for preliminary screening of torsadogenicity of drugs and drug-candidates. II. J Appl Toxicol 2007; 27:270-5. [PMID: 17265420 DOI: 10.1002/jat.1208] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Experimental approaches on anaesthetised guinea pigs have been shown recently to be satisfactorily predictive of the torsadogenic risk of drugs. This work aimed at obtaining additional data, for a further understanding of the reliability and/or the limits of this model. Clonidine (non-torsadogenic in humans) induced a lengthening of the ECG parameter of RR in anaesthetised guinea pigs, without any corresponding increase of QT (corrected by the algorithms of Bazett and Fridericia). Thus, 'QT correct' prolonging effects produced by drugs torsadogenic in humans, on the guinea pig model are primarily due to inhibition of cardiac repolarisation. The corresponding RR prolongation is a consequence (not the cause) of this primary effect. Astemizole, haloperidol and terfenadine, torsadogenic in humans, produced in Langendorff perfused guinea pig hearts a prolongation of the QT interval. Chlorprotixene (non-torsadogenic) did not produce any significant effect on QT. These results are fully consistent with previous observations in anaesthetised guinea pigs. In Langendorff perfused hearts, pentobarbital does not affect cardiac repolarisation and does not potentiate the QT-prolonging effect of astemizole. Together with the findings reported by many authors, these data suggest that ECG recording in anaesthetised guinea pigs is a reliable model for cardiac safety studies evaluating the influence of drugs on the repolarisation process.
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Affiliation(s)
- L Testai
- Dipartimento di Psichiatria, Neurobiologia, Farmacologia e Biotecnologie, Università di Pisa-Via Bonanno, 6 I-56126 Pisa, Italy
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Takahara A, Sugiyama A, Hashimoto K. Reduction of repolarization reserve by halothane anaesthesia sensitizes the guinea-pig heart for drug-induced QT interval prolongation. Br J Pharmacol 2006; 146:561-7. [PMID: 16056235 PMCID: PMC1751191 DOI: 10.1038/sj.bjp.0706352] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
The utility of halothane-anaesthetized guinea-pigs as an in vivo model for predicting the clinical potential of a drug to induce QT interval prolongation was assessed using the electrocardiogram and monophasic action potential (MAP) recordings with electrical ventricular pacing. Intravenous administration of D-sotalol (0.3 mg kg(-1)) and terfenadine (0.3 mg kg(-1)), blockers of a rapid component of delayed rectifier potassium currents, prolonged the QT interval by 32+/-7 and 23+/-6 ms, respectively, whereas chromanol 293B (1 mg kg(-1)), a blocker of a slow component of delayed rectifier potassium currents, lengthened it by 33+/-8 ms. The extent of the QT interval prolongation by these drugs was greater than those in previous reports using pentobarbital-anaesthetized guinea-pigs. The MAP duration at the control was shortened by decreasing the pacing cycle length from 400 to 200 ms, but the MAP duration at each cycle length was prolonged by D-sotalol. The formulas of Van de Water, Matsunaga, Fridericia and Bazett showed good correlation of the repolarization period when compared with the MAP duration at a pacing cycle length of 400 ms. The halothane-anaesthetized guinea-pig model may possess enough sensitivity to detect drug-induced QT interval prolongation, indicating that halothane anaesthesia can reduce the repolarization reserve of the heart in vivo.
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Affiliation(s)
- Akira Takahara
- Department of Pharmacology, Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, Tamaho-cho, Nakakoma-gun, Yamanashi 409-3898, Japan
| | - Atsushi Sugiyama
- Department of Pharmacology, Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, Tamaho-cho, Nakakoma-gun, Yamanashi 409-3898, Japan
- Author for correspondence:
| | - Keitaro Hashimoto
- Department of Pharmacology, Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, Tamaho-cho, Nakakoma-gun, Yamanashi 409-3898, Japan
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Sakaguchi Y, Sugiyama A, Takao S, Akie Y, Takahara A, Hashimoto K. Halothane sensitizes the guinea-pig heart to pharmacological IKr blockade: comparison with urethane anesthesia. J Pharmacol Sci 2005; 99:185-90. [PMID: 16217143 DOI: 10.1254/jphs.fp0050295] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
Abstract
Potential utility of halothane-anesthetized guinea pigs for detecting drug-induced repolarization delay was analyzed in comparison with urethane-anesthesia (n = 4 for both groups). Basal QT interval was significantly greater under halothane-anesthesia than urethane-anesthesia (192 +/- 7 vs 132 +/- 5 ms, respectively), whereas the reverse was true for the heart rate (190 +/- 7 vs 248 +/- 11 beats/min, respectively). The typical I(Kr)-blocker dl-sotalol (0.1 to 3 mg/kg, i.v.) induced dose-related bradycardia and QT interval prolongation under each anesthesia. The extent of maximum prolongation in the QT interval was greater under halothane-anesthesia than urethane-anesthesia (+101 +/- 15 vs +49 +/- 3 ms, respectively), whereas that of peak change in the heart rate was smaller under the former than the latter (-49 +/- 8 vs -63 +/- 5 beats/min, respectively). Pretreatment of the animals under urethane-anesthesia with the selective I(Ks) blocker chromanol 293B (n = 6) increased the extent of the dl-sotalol-induced QT interval prolongation to +57 +/- 8 ms, which was only 0.56 times of that under the halothane-anesthesia, whereas the pretreatment increased the peak change in the heart rate to -76 +/- 12 ms. These results indicate that the halothane-anesthesia may effectively sensitize the guinea-pig heart to pharmacological I(Kr) blockade.
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Affiliation(s)
- Yasue Sakaguchi
- Department of Pharmacology, Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, Tamaho-cho, Nakakoma-gun, Yamanashi 409-3898, Japan
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Hauser DS, Stade M, Schmidt A, Hanauer G. Cardiovascular parameters in anaesthetized guinea pigs: A safety pharmacology screening model. J Pharmacol Toxicol Methods 2005; 52:106-14. [PMID: 15961325 DOI: 10.1016/j.vascn.2005.03.003] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2005] [Accepted: 03/13/2005] [Indexed: 11/24/2022]
Abstract
INTRODUCTION Assessment of cardiovascular functions in vivo is part of the core battery of guideline ICH S7A and is thereby required by regulatory authorities. The haemodynamic effects of repeated intravenous administrations of reference compounds were analyzed in order to validate the guinea pig model for safety pharmacology studies under GLP conditions. METHODS Male guinea pigs (n=54, weighing 565-762 g) were anaesthetized using 1.5 g/kg, i.p., urethane. Systolic arterial blood pressure (SAP), diastolic arterial blood pressure (DAP), heart rate (HR), left ventricular pressure (LVP), cardiac contractility (dp/dt(max)), and ECG (RR, QT, and QTc intervals) were recorded continuously. Animals received vehicle i.v. followed by cumulative doses of reference compounds. RESULTS Vehicle did not produce any relevant changes, either in cardiovascular or ECG parameters. Isoproterenol caused a rapid and significant increase in HR, LVP, and dp/dt(max), in contrast to a dose-dependent decrease in SAP and DAP. Epinephrine led to a potent increase in all cardiovascular parameters. Nifedipine produced a slight decrease in HR and LVP, and a potent decrease in blood pressure and dp/dt(max). Verapamil caused a dose-dependent decrease in all cardiovascular parameters. Ouabain resulted in a significant increase in SAP, DAP, LVP, and dp/dt(max); ECG showed an atrioventricular block and arrhythmia. Terfenadine, cisapride, and sotalol prolonged QT and QTc intervals, whereas vehicle and the other tested compounds did not produce any prolongation of the QTc interval. DISCUSSION Our results on HR, blood pressure, and ECG obtained after i.v. administration of reference compounds show the usefulness of the guinea pig in assessing cardiovascular safety. The anaesthetized guinea pig allows the measurement of cardiac contractility and the use of doses higher than in conscious animals. Using this animal model, several cardiovascular parameters can be recorded simultaneously at a modest cost in terms of test compound and the number of animals required.
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Affiliation(s)
- Daniela S Hauser
- Department of Pharmacology Gastroenterology, ALTANA Pharma AG, Byk-Gulden-Str. 2, Constance 78467, Germany.
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