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Langston JL, Moffett MC, Pennington MR, Myers TM. Pharmacokinetics and pharmacodynamics of standard nerve agent medical countermeasures in Göttingen Minipigs. Toxicol Lett 2024; 397:103-116. [PMID: 38703967 DOI: 10.1016/j.toxlet.2024.04.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Revised: 04/18/2024] [Accepted: 04/26/2024] [Indexed: 05/06/2024]
Abstract
Animal research continues to serve a critical role in the testing and development of medical countermeasures. The Göttingen minipig, developed for laboratory research, may provide many benefits for addressing research questions within chemical defense. Targeted development of the Göttingen minipig model could reduce reliance upon non-human primates, and improve study design, statistical power, and throughput to advance medical countermeasures for regulatory approval and fielding. In this vein, we completed foundational pharmacokinetics and physiological safety studies of intramuscularly administered atropine sulfate, pralidoxime chloride (2-PAM), and diazepam across a broad range of doses (1-6 autoinjector equivalent) using adult male Göttingen minipigs (n=11; n=4-8/study) surgically implanted with vascular access ports and telemetric devices to monitor cardiovascular, respiratory, arterial pressure, and temperature signals. Pharmacokinetic data were orderly and the concentration maximum mirrored available human data at comparably scaled doses clearly for atropine, moderately for 2-PAM, and poorly for diazepam. Time to peak concentration approximated 2, 7, and 20 min for atropine, 2-PAM, and diazepam, respectively, and the elimination half-life of these drugs approximated 2 hr (atropine), 3 hr (2-PAM), and 8 hr (diazepam). Atropine sulfate dose-dependently increased the magnitude and duration of tachycardia and decreased the PR and ST intervals (consistent with findings obtained from other species). Mild hypothermia was observed at the highest diazepam dose. Göttingen minipigs appear to provide a ready and appropriate large animal alternative to non-human primates, and further development and evaluation of novel nerve agent medical countermeasures and treatment strategies in this model are justified.
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Affiliation(s)
- Jeffrey L Langston
- United States Army Medical Research Institute of Chemical Defense, Medical Toxicology Research Division, Pharmaceutical Sciences Department, Aberdeen Proving Ground, MD 21010-5400, USA
| | - Mark C Moffett
- United States Army Medical Research Institute of Chemical Defense, Medical Toxicology Research Division, Pharmaceutical Sciences Department, Aberdeen Proving Ground, MD 21010-5400, USA
| | - M Ross Pennington
- United States Army Medical Research Institute of Chemical Defense, Medical Toxicology Research Division, Pharmaceutical Sciences Department, Aberdeen Proving Ground, MD 21010-5400, USA
| | - Todd M Myers
- United States Army Medical Research Institute of Chemical Defense, Medical Toxicology Research Division, Pharmaceutical Sciences Department, Aberdeen Proving Ground, MD 21010-5400, USA.
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2
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Rossman EI, Wisialowski TA, Vargas HM, Valentin JP, Rolf MG, Roche BM, Riley S, Pugsley MK, Nichols J, Li D, Leishman DJ, Kleiman RB, Greiter-Wilke A, Gintant GA, Engwall MJ, Delaunois A, Authier S. Best practice considerations for nonclinical in vivo cardiovascular telemetry studies in non-rodent species: Delivering high quality QTc data to support ICH E14/S7B Q&As. J Pharmacol Toxicol Methods 2023; 123:107270. [PMID: 37164235 DOI: 10.1016/j.vascn.2023.107270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Revised: 05/02/2023] [Accepted: 05/06/2023] [Indexed: 05/12/2023]
Abstract
The ICH E14/S7B Questions and Answers (Q&As) guideline introduces the concept of a "double negative" nonclinical scenario (negative hERG assay and negative in vivo QTc study) to demonstrate that a drug does not produce a clinically relevant QT prolongation (i.e., no QT liability). This nonclinical "double negative" data package, along with negative Phase 1 clinical QTc data, may be sufficient to substitute for a clinical Thorough QT (TQT) study in some specific cases. While standalone GLP in vivo cardiovascular studies in non-rodent species are standard practice during nonclinical drug development for small molecule programs, a variety of approaches to the design, conduct, analysis and interpretation are utilized across pharmaceutical companies and contract research organizations (CROs) that may, in some cases, negatively impact the stringent sensitivity needed to fulfill the new Q&As. Subject matter experts from both Pharma and CROs have collaborated to recommend best practices for more robust nonclinical cardiovascular telemetry studies in non-rodent species, with input from clinical and regulatory experts. The aim was to increase consistency and harmonization across the industry and to ensure delivery of high quality nonclinical QTc data to meet the proposed sensitivities defined within the revised ICH E14/S7B Q&As guideline (Q&As 5.1 and 6.1). The detailed best practice recommendations presented here cover the design and execution of the safety pharmacology cardiovascular study, including optimal methods for acquiring, analyzing, reporting, and interpreting the resulting QTc and pharmacokinetic data to allow for direct comparison to clinical exposures and assessment of safety margin for QTc prolongation.
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Affiliation(s)
- Eric I Rossman
- GSK, Nonclinical Safety, Safety Pharmacology, Collegeville, PA, USA.
| | - Todd A Wisialowski
- Pfizer Worldwide Research Development and Medical, Safety Pharmacology, Groton, CT, USA
| | - Hugo M Vargas
- Amgen Research, Translational Safety & Bioanalytical Sciences, Thousand Oaks, CA, USA
| | | | - Michael G Rolf
- AstraZeneca, Clinical Pharmacology & Safety Sciences, R&D, Gothenburg, Sweden
| | - Brian M Roche
- Charles River Laboratories, Global Safety Pharmacology, Ashland, OH, USA
| | - Steve Riley
- Pfizer Worldwide Research Development and Medical, Clinical Pharmacology, Groton, CT, USA
| | | | - Jill Nichols
- Labcorp Early Development Laboratories Inc., Madison, WI, USA
| | - Dingzhou Li
- Pfizer Global Product Development, Global Biometrics & Data Management, Groton, CT, USA
| | | | | | | | | | - Michael J Engwall
- Amgen Research, Translational Safety & Bioanalytical Sciences, Thousand Oaks, CA, USA
| | - Annie Delaunois
- UCB Biopharma SRL, Chemin du Foriest, B-1420 Braine-l'Alleud, Belgium
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Kőrösi D, Vorobcsuk A, Fajtai D, Tátrai O, Bodor E, Farkas K, Garamvölgyi R. Adaptation of closed-chest infarction porcine model to adult Pannon minipigs. J Pharmacol Toxicol Methods 2023; 123:107469. [PMID: 37598810 DOI: 10.1016/j.vascn.2023.107469] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Revised: 08/17/2023] [Accepted: 08/17/2023] [Indexed: 08/22/2023]
Abstract
The aim of the recent study was to collect data on the genotype characteristics of the Hungarian self-bred Pannon minipigs by adapting a standardized infarct model procedure. Closed chest AMI was induced by balloon occlusion for 90 min in the left anterior descendent coronary artery (LAD) in 24 adult intact female minipigs followed by reperfusion. To assess the left ventricular (LV) function, serial cardiac magnetic resonance imaging (cMRI) was performed prior to the experimental procedure, on day 3 post-AMI (72 ± 12 h), and at 1 month follow-up (Day 30 ± 2 days). Compared to baseline cMRI scans the end-diastolic volume (EDV) was increased on days 3 and 30 On day 3 the left ventricular ejection fraction (LVEF) decreased significantly but there was no statistical difference between the baseline and day 30 measurements. Cardiac output, stroke volume, and end-systolic volume significantly were increased compared to baseline on day 30 A high percentage (54%) of malignant arrhythmias occurred during the AMI procedure, with a 25% mortality rate. The compensatory capacity of the Pannon minipig heart is excellent therefore the use of different cardiac parameters and invasive measurements is advisable in chronic pharmacological experiments to complement cMRI data.
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Affiliation(s)
- Dénes Kőrösi
- Hungarian University of Agriculture and Life Sciences, Doctoral School in Animal Science, Kaposvár Campus, 40. Guba S. Kaposvár, Kaposvár H-7400, Hungary.
| | - András Vorobcsuk
- Kaposi Moritz Teaching Hospital, Department of Cardiology, 20-32. Tallián Gy. Kaposvár, Kaposvár H-7400, Hungary; Medical School, University of Pécs, Pf. 99, H-7601 Pécs, Hungary
| | - Dániel Fajtai
- Medicopus Nonprofit Ltd., 40. Guba S. Kaposvár, Kaposvár H-7400, Hungary
| | - Ottó Tátrai
- Kaposi Moritz Teaching Hospital, Department of Cardiology, 20-32. Tallián Gy. Kaposvár, Kaposvár H-7400, Hungary
| | - Emőke Bodor
- Kaposi Moritz Teaching Hospital, Department of Cardiology, 20-32. Tallián Gy. Kaposvár, Kaposvár H-7400, Hungary
| | - Kornélia Farkas
- Institute of Bioanalysis, Medical School, University of Pécs, 1. Honvéd Pécs, Pécs H-7624, Hungary
| | - Rita Garamvölgyi
- Hungarian University of Agriculture and Life Sciences, Doctoral School in Animal Science, Kaposvár Campus, 40. Guba S. Kaposvár, Kaposvár H-7400, Hungary
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4
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Osadchii OE. Electrocardiographic marker of the cardiac action potential triangulation induced by antiarrhythmic drugs in perfused guinea-pig heart. Exp Physiol 2022; 107:864-878. [PMID: 35561081 DOI: 10.1113/ep090349] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Accepted: 05/09/2022] [Indexed: 11/08/2022]
Abstract
NEW FINDINGS What is the central question of this study? Can triangular appearance of ventricular action potential, indicating proarrhythmic profile of antiarrhythmic agent, be approximated by specific changes on ECG? What is the main finding and its importance? The triangulation of the ventricular action potential seen when antiarrhythmic drugs induce a greater lengthening of the late repolarization compared to the initial repolarization in epicardium, is closely approximated by a greater prolongation of the T wave upslope relative to the interval between the J point and the start of the T wave (the JTstart interval) on ECG. These findings may improve the power of ECG assessments in predicting the drug-induced arrhythmia resulting from slowed phase 3 repolarization. ABSTRACT Antiarrhythmic drugs prescribed to treat atrial fibrillation can occasionally precipitate ventricular tachyarrhythmia through a prominent slowing of the phase 3 repolarization. The latter results in the triangular shape of ventricular action potential, indicating high arrhythmic risks. However, clinically, the utilility of triangulation assessments for predicting arrhythmia is limited owing to the invasive nature of the ventricular action potential recordings. This study examined whether the triangulation effect can be detected indirectly from ECG analysis. Epicardial monophasic action potentials and ECG were simultaneously recorded in perfused guinea-pig hearts. With antiarrhythmics (dofetilide, quinidine, procainamide and flecainide), a prolongation of the initial repolarization seen in the action potential recordings was closely approximated by lengthening of the interval bewteen the J point and the start of the T wave (the JTstart interval) on ECG, whereas a prolongation of the late repolarization was paralleled by widening of the T wave upslope. Dofetilide, quinidine and procainamide induced a prominent slowing of the phase 3 repolarization in epicardium, leading to triangulation of the action potential. These effects were accompanied by a greater prolongation of the T wave upslope compared to the JTstart interval. Flecainide elicited a proportional prolongation of the initial and the late ventricular repolarization, and therefore failed to induce triangulation, based on analysis of both epicardial action potential and ECG profiles. Collectively, these findings suggest that the ratio between the durations of the T wave upslope and the JTstart interval may represent ECG metric of the ventricular action potential triangulation induced by antiarrhythmic drugs. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Oleg E Osadchii
- Department of Biomedical Sciences, University of Copenhagen, Blegdamsvej 3, 2200, Copenhagen N, Denmark.,Department of Pharmacology, Kuban State Medical University, Sedin Street 4, Krasnodar, 350063, Russia
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5
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Odening KE, Gomez AM, Dobrev D, Fabritz L, Heinzel FR, Mangoni ME, Molina CE, Sacconi L, Smith G, Stengl M, Thomas D, Zaza A, Remme CA, Heijman J. ESC working group on cardiac cellular electrophysiology position paper: relevance, opportunities, and limitations of experimental models for cardiac electrophysiology research. Europace 2021; 23:1795-1814. [PMID: 34313298 DOI: 10.1093/europace/euab142] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2021] [Accepted: 05/19/2021] [Indexed: 12/19/2022] Open
Abstract
Cardiac arrhythmias are a major cause of death and disability. A large number of experimental cell and animal models have been developed to study arrhythmogenic diseases. These models have provided important insights into the underlying arrhythmia mechanisms and translational options for their therapeutic management. This position paper from the ESC Working Group on Cardiac Cellular Electrophysiology provides an overview of (i) currently available in vitro, ex vivo, and in vivo electrophysiological research methodologies, (ii) the most commonly used experimental (cellular and animal) models for cardiac arrhythmias including relevant species differences, (iii) the use of human cardiac tissue, induced pluripotent stem cell (hiPSC)-derived and in silico models to study cardiac arrhythmias, and (iv) the availability, relevance, limitations, and opportunities of these cellular and animal models to recapitulate specific acquired and inherited arrhythmogenic diseases, including atrial fibrillation, heart failure, cardiomyopathy, myocarditis, sinus node, and conduction disorders and channelopathies. By promoting a better understanding of these models and their limitations, this position paper aims to improve the quality of basic research in cardiac electrophysiology, with the ultimate goal to facilitate the clinical translation and application of basic electrophysiological research findings on arrhythmia mechanisms and therapies.
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Affiliation(s)
- Katja E Odening
- Translational Cardiology, Department of Cardiology, Inselspital, Bern University Hospital, Bern, Switzerland.,Institute of Physiology, University of Bern, Bern, Switzerland
| | - Ana-Maria Gomez
- Signaling and cardiovascular pathophysiology-UMR-S 1180, Inserm, Université Paris-Saclay, 92296 Châtenay-Malabry, France
| | - Dobromir Dobrev
- Institute of Pharmacology, West German Heart and Vascular Center, University Duisburg-Essen, Essen, Germany
| | - Larissa Fabritz
- Institute of Cardiovascular Sciences, University of Birmingham, Birmingham, UK.,Department of Cardiology, University Hospital Birmingham NHS Trust, Birmingham, UK
| | - Frank R Heinzel
- Department of Internal Medicine and Cardiology, Charité - Universitätsmedizin Berlin, Campus Virchow-Klinikum, Berlin, Germany.,DZHK (German Centre for Cardiovascular Research), Partner Site, Berlin, Germany
| | - Matteo E Mangoni
- Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM, Montpellier, France
| | - Cristina E Molina
- Institute of Experimental Cardiovascular Research, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.,German Centre for Cardiovascular Research (DZHK), Partner Site, Hamburg/Kiel/Lübeck, Germany
| | - Leonardo Sacconi
- National Institute of Optics and European Laboratory for Non Linear Spectroscopy, Italy.,Institute for Experimental Cardiovascular Medicine, University Freiburg, Germany
| | - Godfrey Smith
- Institute of Cardiovascular and Medical Sciences, University of Glasgow, UK
| | - Milan Stengl
- Department of Physiology, Faculty of Medicine in Pilsen, Charles University, Pilsen, Czech Republic
| | - Dierk Thomas
- Department of Cardiology, University Hospital Heidelberg, Heidelberg, Germany; Heidelberg Center for Heart Rhythm Disorders (HCR), University Hospital Heidelberg, Heidelberg, Germany.,German Centre for Cardiovascular Research (DZHK), Partner Site, Heidelberg/Mannheim, Germany
| | - Antonio Zaza
- Department of Biotechnology and Bioscience, University of Milano-Bicocca, Milano, Italy
| | - Carol Ann Remme
- Department of Experimental Cardiology, Amsterdam UMC, location AMC, Amsterdam, The Netherlands
| | - Jordi Heijman
- Department of Cardiology, CARIM School for Cardiovascular Diseases, Maastricht University, Maastricht, The Netherlands
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6
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Sattler SM, Skibsbye L, Linz D, Lubberding AF, Tfelt-Hansen J, Jespersen T. Ventricular Arrhythmias in First Acute Myocardial Infarction: Epidemiology, Mechanisms, and Interventions in Large Animal Models. Front Cardiovasc Med 2019; 6:158. [PMID: 31750317 PMCID: PMC6848060 DOI: 10.3389/fcvm.2019.00158] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2019] [Accepted: 10/18/2019] [Indexed: 12/22/2022] Open
Abstract
Ventricular arrhythmia and subsequent sudden cardiac death (SCD) due to acute myocardial infarction (AMI) is one of the most frequent causes of death in humans. Lethal ventricular arrhythmias like ventricular fibrillation (VF) prior to hospitalization have been reported to occur in more than 10% of all AMI cases and survival in these patients is poor. Identification of risk factors and mechanisms for VF following AMI as well as implementing new risk stratification models and therapeutic approaches is therefore an important step to reduce mortality in people with high cardiovascular risk. Studying spontaneous VF following AMI in humans is challenging as it often occurs unexpectedly in a low risk subgroup. Large animal models of AMI can help to bridge this knowledge gap and are utilized to investigate occurrence of arrhythmias, involved mechanisms and therapeutic options. Comparable anatomy and physiology allow for this translational approach. Through experimental focus, using state-of-the-art technologies, including refined electrical mapping equipment and novel pharmacological investigations, valuable insights into arrhythmia mechanisms and possible interventions for arrhythmia-induced SCD during the early phase of AMI are now beginning to emerge. This review describes large experimental animal models of AMI with focus on first AMI-associated ventricular arrhythmias. In this context, epidemiology of first AMI, arrhythmogenic mechanisms and various potential therapeutic pharmacological targets will be discussed.
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Affiliation(s)
- Stefan Michael Sattler
- Department of Cardiology, Heart Centre, Copenhagen University Hospital, Copenhagen, Denmark.,Medical Department I, University Hospital Grosshadern, LMU Munich, Munich, Germany
| | - Lasse Skibsbye
- Department of Exploratory Toxicology, H. Lundbeck A/S, Copenhagen, Denmark
| | - Dominik Linz
- Medical Department III, Universitätsklinikum des Saarlandes, Homburg, Germany.,Centre for Heart Rhythm Disorders, South Australian Health and Medical Research Institute, Royal Adelaide Hospital, University of Adelaide, Adelaide, SA, Australia
| | - Anniek Frederike Lubberding
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Jacob Tfelt-Hansen
- Department of Cardiology, Heart Centre, Copenhagen University Hospital, Copenhagen, Denmark.,Department of Forensic Medicine, Faculty of Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Thomas Jespersen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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Morton LD, Sanders M, Reagan WJ, Crabbs TA, McVean M, Funk KA. Confounding Factors in the Interpretation of Preclinical Studies. Int J Toxicol 2019; 38:228-234. [PMID: 30975012 DOI: 10.1177/1091581819837157] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
A number of issues may arise during the conduct of a study which can complicate interpretation of in vitro and in vivo datasets. Speakers discussed the implications of differing interpretations and how to avoid complicating factors during study planning and execution. Consideration needs to be given to study design factors including defining objectives, consideration of expected pharmacological effects, dose selection and drug kinetics, species used, and vehicle selection. In addition, the effects of vivarium temperature effects on various endpoints, how to control variables affecting clinical pathology, and how early death animals, common background findings, and artifacts can affect histopathology interpretation all play into the final interpretation of study data.
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Affiliation(s)
| | | | - William J Reagan
- 3 Pfizer Global Research and Development Eastern, Groton, CT, USA
| | | | - Maralee McVean
- 5 PreClinical Research Services, Inc, Fort Collins, CO, USA
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8
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Yokoyama H, Nakamura Y, Saito H, Nagayama Y, Hoshiai K, Wada T, Izumi-Nakaseko H, Ando K, Akie Y, Sugiyama A. Pharmacological characterization of microminipig as a model to assess the drug-induced cardiovascular responses for non-clinical toxicity and/or safety pharmacology studies. J Toxicol Sci 2017; 42:93-101. [PMID: 28070113 DOI: 10.2131/jts.42.93] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
We tried to establish the halothane-anesthetized microminipigs as an alternative animal model for non-clinical toxicity and/or safety pharmacology studies. In order to characterize the halothane-anesthetized microminipigs, we firstly clarified the effects of halothane anesthesia on their cardiovascular system (n = 5). Then, we examined the cardiovascular effects of dl-sotalol in doses of 0.1, 0.3 and 1 mg/kg, i.v. on the halothane-anesthetized microminipigs (n = 6). Induction of the halothane anesthesia by itself prolonged the QT interval as well as QTcF, suggesting that the halothane anesthesia can reduce the cardiac repolarization reserve in microminipigs like in dogs. dl-Sotalol showed more potent negative chronotropic, dromotropic and hypotensive effects together with repolarization delay in microminipigs than in dogs, although each cardiovascular response to dl-sotalol was directionally similar between them, suggesting greater basal sympathetic tone and/or smaller volume of distribution of the drug in microminipigs than in dogs. Analyses of proarrhythmic surrogate markers indicate that Tpeak-Tend and short-term variability of QT interval may be more sensitive to detect the dl-sotalol-induced direct electrophysiological changes in microminipigs than in dogs, but its reverse will be true for J-Tpeakc. Thus, these results may help better understand the drug-induced cardiovascular responses in microminipigs.
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9
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Ion currents of cardiomyocytes in different regions of the Göttingen minipig heart. J Pharmacol Toxicol Methods 2017; 86:12-18. [PMID: 28254506 DOI: 10.1016/j.vascn.2017.02.022] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Revised: 01/18/2017] [Accepted: 02/20/2017] [Indexed: 01/25/2023]
Abstract
INTRODUCTION The Göttingen minipig is a promising model for pharmacological safety assessment and for translational research in cardiology. We have examined the main ion currents in cardiomyocytes of the minipig heart. METHODS Cardiac cells were isolated from different cardiac regions (endo-, mid- and epicardial left ventricle and right ventricle) from Göttingen minipigs and examined using the whole cell patch clamp technique combined with pharmacological interventions. RESULTS The inward rectifier (IK1), the delayed rectifier (IK), with the rapid and slow components, (IKr, IKs) and the L-type Ca2+ channel (ICa,L) were identified in the different regions of the heart, whereas the Ca2+-independent transient outward current (Ito1) was observed in only a few cells. IK1 was similar in the cardiac regions with a slightly lower value in the epicardial cells. IKs was smaller in epi- and endo-cardial regions. DISCUSSION The equivalents of the main human cardiac ion currents are present in the minipig cardiomyocytes with the exception of the Ca2+-independent Ito1. The study provides further evidence that the minipig is a valid model for investigating cardiovascular pharmacology.
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Morissette P, Regan C, Fitzgerald K, Gerenser P, Travis J, Wang S, Fanelli P, Sannajust F. Shortening of the electromechanical window in the ketamine/xylazine-anesthetized guinea pig model to assess pro-arrhythmic risk in early drug development. J Pharmacol Toxicol Methods 2016; 81:171-82. [DOI: 10.1016/j.vascn.2016.06.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Revised: 05/23/2016] [Accepted: 06/04/2016] [Indexed: 11/26/2022]
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11
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Trenor B, Gomis-Tena J, Cardona K, Romero L, Rajamani S, Belardinelli L, Giles WR, Saiz J. In silico assessment of drug safety in human heart applied to late sodium current blockers. Channels (Austin) 2015; 7:249-62. [PMID: 23696033 DOI: 10.4161/chan.24905] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Drug-induced action potential (AP) prolongation leading to Torsade de Pointes is a major concern for the development of anti-arrhythmic drugs. Nevertheless the development of improved anti-arrhythmic agents, some of which may block different channels, remains an important opportunity. Partial block of the late sodium current (I(NaL)) has emerged as a novel anti-arrhythmic mechanism. It can be effective in the settings of free radical challenge or hypoxia. In addition, this approach can attenuate pro-arrhythmic effects of blocking the rapid delayed rectifying K(+) current (I(Kr)). The main goal of our computational work was to develop an in-silico tool for preclinical anti-arrhythmic drug safety assessment, by illustrating the impact of I(Kr)/I(NaL) ratio of steady-state block of drug candidates on "torsadogenic" biomarkers. The O'Hara et al. AP model for human ventricular myocytes was used. Biomarkers for arrhythmic risk, i.e., AP duration, triangulation, reverse rate-dependence, transmural dispersion of repolarization and electrocardiogram QT intervals, were calculated using single myocyte and one-dimensional strand simulations. Predetermined amounts of block of I(NaL) and I(Kr) were evaluated. "Safety plots" were developed to illustrate the value of the specific biomarker for selected combinations of IC(50)s for I(Kr) and I(NaL) of potential drugs. The reference biomarkers at baseline changed depending on the "drug" specificity for these two ion channel targets. Ranolazine and GS967 (a novel potent inhibitor of I(NaL)) yielded a biomarker data set that is considered safe by standard regulatory criteria. This novel in-silico approach is useful for evaluating pro-arrhythmic potential of drugs and drug candidates in the human ventricle.
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12
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The potassium current carried by TREK-1 channels in rat cardiac ventricular muscle. Pflugers Arch 2014; 467:1069-79. [PMID: 25539776 DOI: 10.1007/s00424-014-1678-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2014] [Revised: 12/15/2014] [Accepted: 12/16/2014] [Indexed: 01/13/2023]
Abstract
We studied the potassium current flowing through TREK-1 channels in rat cardiac ventricular myocytes. We separated the TREK-1 current from other current components by blocking most other channels with a blocker cocktail. We tried to inhibit the TREK-1 current by activating protein kinase A (PKA) with a mixture of forskolin and isobutyl-methylxanthine (IBMX). Activation of PKA blocked an outwardly rectifying current component at membrane potentials positive to -40 mV. At 37 °C, application of forskolin plus IBMX reduced the steady-state outward current measured at positive voltages by about 52 %. Application of the potassium channel blockers quinidine or tetrahexylammonium also reduced the steady-state outward current by about 50 %. Taken together, our results suggest that the increase in temperature from 22 to 37 °C increased the TREK-1 current by a factor of at least 5 and that the average density of the TREK-1 current in rat cardiomyocytes at 37 °C is about 1.5 pA/pF at +30 mV. The contribution of TREK-1 to the action potential was assessed by using a dynamic patch clamp technique. After subtraction of simulated TREK-1 currents, action potential duration at 50 or 90 % repolarisation was increased by about 12 %, indicating that TREK-1 may be functionally important in rat ventricular muscle. During sympathetic stimulation, inhibition of TREK-1 channels via PKA is expected to prolong the action potential primarily in subendocardial myocytes; this may decrease the transmural dispersion of repolarisation and thus may serve to prevent the occurrence of arrhythmias.
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13
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Jing L, Brownson K, Patwardhan A. Role of slow delayed rectifying potassium current in dynamics of repolarization and electrical memory in swine ventricles. J Physiol Sci 2014; 64:185-93. [PMID: 24682806 PMCID: PMC10717138 DOI: 10.1007/s12576-014-0310-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2013] [Accepted: 03/03/2014] [Indexed: 01/26/2023]
Abstract
Dynamics of repolarization, quantified as restitution and electrical memory, impact conduction stability. Relatively less is known about role of slow delayed rectifying potassium current, I(Ks), in dynamics of repolarization and memory compared to the rapidly activating current I(Kr). Trans-membrane potentials were recorded from right ventricular tissues from pigs during reduction (chromanol 293B) and increases in I(Ks) (mefenamic acid). A novel pacing protocol was used to explicitly control diastolic intervals to quantify memory. Restitution hysteresis, a consequence of memory, increased after chromanol 293B (loop thickness and area increased 27 and 38 %) and decreased after mefenamic acid (52 and 53 %). Standard and dynamic restitutions showed an increase in average slope after chromanol 293B and a decrease after mefenamic acid. Increase in slope and memory are hypothesized to have opposite effects on electrical stability; therefore, these results suggest that reduction and enhancement of I(Ks) likely also have offsetting components that affect stability.
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Affiliation(s)
- Linyuan Jing
- Department of Biomedical Engineering, University of Kentucky, Lexington, KY USA
| | - Kathleen Brownson
- Department of Biomedical Engineering, University of Kentucky, Lexington, KY USA
| | - Abhijit Patwardhan
- Department of Biomedical Engineering, University of Kentucky, Lexington, KY USA
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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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15
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Ganderup NC, Harvey W, Mortensen JT, Harrouk W. The minipig as nonrodent species in toxicology--where are we now? Int J Toxicol 2012; 31:507-28. [PMID: 23134714 DOI: 10.1177/1091581812462039] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Over the past 3 decades minipigs have moved from being an obscure alternative to dogs and nonhuman primates to being a standard animal model in regulatory toxicity studies. This article covers the use of minipigs as a model in the context of nonclinical drug safety and provides an overview of the minipig's developmental history and relates minipigs to other animal species commonly used in toxicology; and the minipig's translational power is supported by 43 case studies of marketed drug products covered. Special focus is given to criteria for selecting minipigs in nonclinical programs supporting the development of new medicines; the use of swine in the assessment of food additives, agrochemicals, and pesticides; as well as a regulatory perspective on the use of minipigs in Food and Drug Administration (FDA)-regulated products. This article presents the main points conveyed at a symposium held at the 2010 American College of Toxicology meeting in Baltimore, Maryland.
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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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Keeping the rhythm — Pro-arrhythmic investigations in isolated Göttingen minipig hearts. J Pharmacol Toxicol Methods 2011; 64:134-44. [DOI: 10.1016/j.vascn.2011.05.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2011] [Revised: 04/27/2011] [Accepted: 05/02/2011] [Indexed: 01/08/2023]
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Authier S, Gervais J, Fournier S, Gauvin D, Maghezzi S, Troncy E. Cardiovascular and respiratory safety pharmacology in Göttingen minipigs: Pharmacological characterization. J Pharmacol Toxicol Methods 2011; 64:53-9. [DOI: 10.1016/j.vascn.2011.04.007] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2011] [Revised: 04/19/2011] [Accepted: 04/23/2011] [Indexed: 11/30/2022]
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