1
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Jin Q, Greenstein JL, Winslow RL. Estimating the probability of early afterdepolarizations and predicting arrhythmic risk associated with long QT syndrome type 1 mutations. Biophys J 2023; 122:4042-4056. [PMID: 37705243 PMCID: PMC10598291 DOI: 10.1016/j.bpj.2023.09.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Revised: 08/29/2023] [Accepted: 09/08/2023] [Indexed: 09/15/2023] Open
Abstract
Early afterdepolarizations (EADs) are action potential (AP) repolarization abnormalities that can trigger lethal arrhythmias. Simulations using biophysically detailed cardiac myocyte models can reveal how model parameters influence the probability of these cellular arrhythmias; however, such analyses can pose a huge computational burden. We have previously developed a highly simplified approach in which logistic regression models (LRMs) map parameters of complex cell models to the probability of ectopic beats. Here, we extend this approach to predict the probability of EADs (P(EAD)) as a mechanistic metric of arrhythmic risk. We use the LRM to investigate how changes in parameters of the slow-activating delayed rectifier current (IKs) affect P(EAD) for 17 different long QT syndrome type 1 (LQTS1) mutations. In this LQTS1 clinical arrhythmic risk prediction task, we compared P(EAD) for these 17 mutations with two other recently published model-based arrhythmia risk metrics (AP morphology metric across populations of myocyte models and transmural repolarization prolongation based on a one-dimensional [1D] tissue-level model). These model-based risk metrics yield similar prediction performance; however, each fails to stratify clinical risk for a significant number of the 17 studied LQTS1 mutations. Nevertheless, an interpretable ensemble model using multivariate linear regression built by combining all of these model-based risk metrics successfully predicts the clinical risk of 17 mutations. These results illustrate the potential of computational approaches in arrhythmia risk prediction.
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Affiliation(s)
- Qingchu Jin
- Department of Biomedical Engineering and Institute for Computational Medicine, Johns Hopkins University, Baltimore, Maryland
| | - Joseph L Greenstein
- Department of Biomedical Engineering and Institute for Computational Medicine, Johns Hopkins University, Baltimore, Maryland
| | - Raimond L Winslow
- Department of Biomedical Engineering and Institute for Computational Medicine, Johns Hopkins University, Baltimore, Maryland.
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2
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Jeong DU, Yoo Y, Marcellinus A, Lim KM. Application of Convolutional Neural Networks Using Action Potential Shape for In-Silico Proarrhythmic Risk Assessment. Biomedicines 2023; 11:biomedicines11020406. [PMID: 36830942 PMCID: PMC9953470 DOI: 10.3390/biomedicines11020406] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Revised: 01/16/2023] [Accepted: 01/21/2023] [Indexed: 01/31/2023] Open
Abstract
This study proposes a convolutional neural network (CNN) model using action potential (AP) shapes as input for proarrhythmic risk assessment, considering the hypothesis that machine-learning features automatically extracted from AP shapes contain more meaningful information than do manually extracted indicators. We used 28 drugs listed in the comprehensive in vitro proarrhythmia assay (CiPA), consisting of eight high-risk, eleven intermediate-risk, and nine low-risk torsadogenic drugs. We performed drug simulations to generate AP shapes using experimental drug data, obtaining 2000 AP shapes per drug. The proposed CNN model was trained to classify the TdP risk into three levels, high-, intermediate-, and low-risk, based on in silico AP shapes generated using 12 drugs. We then evaluated the performance of the proposed model for 16 drugs. The classification accuracy of the proposed CNN model was excellent for high- and low-risk drugs, with AUCs of 0.914 and 0.951, respectively. The model performance for intermediate-risk drugs was good, at 0.814. Our proposed model can accurately assess the TdP risks of drugs from in silico AP shapes, reflecting the pharmacokinetics of ionic currents. We need to secure more drugs for future studies to improve the TdP-risk-assessment robustness.
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Affiliation(s)
- Da Un Jeong
- Department of IT Convergence Engineering, Kumoh National Institute of Technology, Gumi 39253, Republic of Korea
| | - Yedam Yoo
- Department of IT Convergence Engineering, Kumoh National Institute of Technology, Gumi 39253, Republic of Korea
| | - Aroli Marcellinus
- Department of IT Convergence Engineering, Kumoh National Institute of Technology, Gumi 39253, Republic of Korea
| | - Ki Moo Lim
- Department of IT Convergence Engineering, Kumoh National Institute of Technology, Gumi 39253, Republic of Korea
- Department of Medical IT Convergence Engineering, Kumoh National Institute of Technology, Gumi 39253, Republic of Korea
- Meta Heart Inc., Gumi 39253, Republic of Korea
- Correspondence: ; Tel.: +82-054-478-7780
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3
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Trovato C, Mohr M, Schmidt F, Passini E, Rodriguez B. Cross clinical-experimental-computational qualification of in silico drug trials on human cardiac purkinje cells for proarrhythmia risk prediction. FRONTIERS IN TOXICOLOGY 2022; 4:992650. [PMID: 36278026 PMCID: PMC9581132 DOI: 10.3389/ftox.2022.992650] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Accepted: 09/20/2022] [Indexed: 11/06/2022] Open
Abstract
The preclinical identification of drug-induced cardiotoxicity and its translation into human risk are still major challenges in pharmaceutical drug discovery. The ICH S7B Guideline and Q&A on Clinical and Nonclinical Evaluation of QT/QTc Interval Prolongation and Proarrhythmic Potential promotes human in silico drug trials as a novel tool for proarrhythmia risk assessment. To facilitate the use of in silico data in regulatory submissions, explanatory control compounds should be tested and documented to demonstrate consistency between predictions and the historic validation data. This study aims to quantify drug-induced electrophysiological effects on in silico cardiac human Purkinje cells, to compare them with existing in vitro rabbit data, and to assess their accuracy for clinical pro-arrhythmic risk predictions. The effects of 14 reference compounds were quantified in simulations with a population of in silico human cardiac Purkinje models. For each drug dose, five electrophysiological biomarkers were quantified at three pacing frequencies, and results compared with available in vitro experiments and clinical proarrhythmia reports. Three key results were obtained: 1) In silico, repolarization abnormalities in human Purkinje simulations predicted drug-induced arrhythmia for all risky compounds, showing higher predicted accuracy than rabbit experiments; 2) Drug-induced electrophysiological changes observed in human-based simulations showed a high degree of consistency with in vitro rabbit recordings at all pacing frequencies, and depolarization velocity and action potential duration were the most consistent biomarkers; 3) discrepancies observed for dofetilide, sotalol and terfenadine are mainly caused by species differences between humans and rabbit. Taken together, this study demonstrates higher accuracy of in silico methods compared to in vitro animal models for pro-arrhythmic risk prediction, as well as a high degree of consistency with in vitro experiments commonly used in safety pharmacology, supporting the potential for industrial and regulatory adoption of in silico trials for proarrhythmia prediction.
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Affiliation(s)
- Cristian Trovato
- Department of Computer Science, University of Oxford, Oxford, United Kingdom
| | - Marcel Mohr
- Sanofi-Aventis Deutschland GmbH, R&D Preclinical Safety, Frankfurt, Germany
| | - Friedemann Schmidt
- Sanofi-Aventis Deutschland GmbH, R&D Preclinical Safety, Frankfurt, Germany
| | - Elisa Passini
- Department of Computer Science, University of Oxford, Oxford, United Kingdom
| | - Blanca Rodriguez
- Department of Computer Science, University of Oxford, Oxford, United Kingdom
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4
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Iseppe AF, Ni H, Zhu S, Zhang X, Coppini R, Yang PC, Srivatsa U, Clancy CE, Edwards AG, Morotti S, Grandi E. Sex-Specific Classification of Drug-Induced Torsade de Pointes Susceptibility Using Cardiac Simulations and Machine Learning. Clin Pharmacol Ther 2021; 110:380-391. [PMID: 33772748 PMCID: PMC8316283 DOI: 10.1002/cpt.2240] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Accepted: 03/16/2021] [Indexed: 11/09/2022]
Abstract
Torsade de Pointes (TdP), a rare but lethal ventricular arrhythmia, is a toxic side effect of many drugs. To assess TdP risk, safety regulatory guidelines require quantification of hERG channel block in vitro and QT interval prolongation in vivo for all new therapeutic compounds. Unfortunately, these have proven to be poor predictors of torsadogenic risk, and are likely to have prevented safe compounds from reaching clinical phases. Although this has stimulated numerous efforts to define new paradigms for cardiac safety, none of the recently developed strategies accounts for patient conditions. In particular, despite being a well-established independent risk factor for TdP, female sex is vastly under-represented in both basic research and clinical studies, and thus current TdP metrics are likely biased toward the male sex. Here, we apply statistical learning to synthetic data, generated by simulating drug effects on cardiac myocyte models capturing male and female electrophysiology, to develop new sex-specific classification frameworks for TdP risk. We show that (i) TdP classifiers require different features in females vs. males; (ii) male-based classifiers perform more poorly when applied to female data; and (iii) female-based classifier performance is largely unaffected by acute effects of hormones (i.e., during various phases of the menstrual cycle). Notably, when predicting TdP risk of intermediate drugs on female simulated data, male-biased predictive models consistently underestimate TdP risk in women. Therefore, we conclude that pipelines for preclinical cardiotoxicity risk assessment should consider sex as a key variable to avoid potentially life-threatening consequences for the female population.
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Affiliation(s)
- Alex Fogli Iseppe
- Department of Pharmacology, University of California, Davis, CA, USA
| | - Haibo Ni
- Department of Pharmacology, University of California, Davis, CA, USA
| | - Sicheng Zhu
- Department of Pharmacology, University of California, Davis, CA, USA
| | - Xianwei Zhang
- Department of Pharmacology, University of California, Davis, CA, USA
| | - Raffaele Coppini
- Department of Neuroscience, Psychology, Drug Sciences and Child Health (NeuroFarBa), University of Florence, Italy
| | - Pei-Chi Yang
- Department of Physiology and Membrane Biology, University of California, Davis, CA, USA
| | - Uma Srivatsa
- Department of Internal Medicine, University of California, Davis, CA, USA
| | - Colleen E. Clancy
- Department of Pharmacology, University of California, Davis, CA, USA
- Department of Physiology and Membrane Biology, University of California, Davis, CA, USA
| | - Andrew G. Edwards
- Department of Pharmacology, University of California, Davis, CA, USA
| | - Stefano Morotti
- Department of Pharmacology, University of California, Davis, CA, USA
| | - Eleonora Grandi
- Department of Pharmacology, University of California, Davis, CA, USA
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5
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Tsui JH, Leonard A, Camp ND, Long JT, Nawas ZY, Chavanachat R, Smith AST, Choi JS, Dong Z, Ahn EH, Wolf-Yadlin A, Murry CE, Sniadecki NJ, Kim DH. Tunable electroconductive decellularized extracellular matrix hydrogels for engineering human cardiac microphysiological systems. Biomaterials 2021; 272:120764. [PMID: 33798964 DOI: 10.1016/j.biomaterials.2021.120764] [Citation(s) in RCA: 49] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Revised: 03/08/2021] [Accepted: 03/12/2021] [Indexed: 12/11/2022]
Abstract
Cardiomyocytes differentiated from human induced pluripotent stem cells (hiPSCs) offer tremendous potential when used to engineer human tissues for drug screening and disease modeling; however, phenotypic immaturity reduces assay reliability when translating in vitro results to clinical studies. To address this, we have developed hybrid hydrogels comprised of decellularized porcine myocardial extracellular matrix (dECM) and reduced graphene oxide (rGO) to provide a more instructive microenvironment for proper cell and tissue development. A tissue-specific protein profile was preserved post-decellularization, and through the modulation of rGO content and degree of reduction, the mechanical and electrical properties of the hydrogels could be tuned. Engineered heart tissues (EHTs) generated using dECM-rGO hydrogel scaffolds and hiPSC-derived cardiomyocytes exhibited significantly increased twitch forces and had increased expression of genes that regulate contractile function. Improvements in various aspects of electrophysiological function, such as calcium-handling, action potential duration, and conduction velocity, were also induced by the hybrid biomaterial. dECM-rGO hydrogels could also be used as a bioink to print cardiac tissues in a high-throughput manner, and these tissues were utilized to assess the proarrhythmic potential of cisapride. Action potential prolongation and beat interval irregularities was observed in dECM-rGO tissues at clinical doses of cisapride, indicating that the enhanced electrophysiological function of these tissues corresponded well with a capability to produce physiologically relevant drug responses.
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Affiliation(s)
- Jonathan H Tsui
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, 21205, USA
| | - Andrea Leonard
- Department of Mechanical Engineering, University of Washington, Seattle, WA, 98105, USA
| | - Nathan D Camp
- Department of Genome Sciences, University of Washington, Seattle, WA, 98105, USA
| | - Joseph T Long
- Department of Bioengineering, University of Washington, Seattle, WA, 98105, USA
| | - Zeid Y Nawas
- Department of Bioengineering, University of Washington, Seattle, WA, 98105, USA
| | | | - Alec S T Smith
- Department of Physiology and Biophysics, University of Washington, Seattle, WA, 98105, USA; Institute for Stem Cell & Regenerative Medicine, University of Washington, Seattle, WA, 98109, USA
| | - Jong Seob Choi
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, 21205, USA
| | - Zhipeng Dong
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, 21205, USA
| | - Eun Hyun Ahn
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, 21205, USA
| | | | - Charles E Murry
- Department of Bioengineering, University of Washington, Seattle, WA, 98105, USA; Department of Pathology, University of Washington, Seattle, WA, 98109, USA; Center for Cardiovascular Biology, University of Washington, Seattle, WA, 98109, USA; Institute for Stem Cell & Regenerative Medicine, University of Washington, Seattle, WA, 98109, USA
| | - Nathan J Sniadecki
- Department of Mechanical Engineering, University of Washington, Seattle, WA, 98105, USA; Department of Bioengineering, University of Washington, Seattle, WA, 98105, USA; Center for Cardiovascular Biology, University of Washington, Seattle, WA, 98109, USA; Institute for Stem Cell & Regenerative Medicine, University of Washington, Seattle, WA, 98109, USA
| | - Deok-Ho Kim
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, 21205, USA; Division of Cardiology, Department of Medicine, Johns Hopkins University, Baltimore, MD, 21205, USA.
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6
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Strauss DG, Wu WW, Li Z, Koerner J, Garnett C. Translational Models and Tools to Reduce Clinical Trials and Improve Regulatory Decision Making for QTc and Proarrhythmia Risk (ICH E14/S7B Updates). Clin Pharmacol Ther 2021; 109:319-333. [PMID: 33332579 PMCID: PMC7898549 DOI: 10.1002/cpt.2137] [Citation(s) in RCA: 49] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Accepted: 12/14/2020] [Indexed: 01/06/2023]
Abstract
After multiple drugs were removed from the market secondary to drug-induced torsade de pointes (TdP) risk, the International Council for Harmonisation (ICH) released guidelines in 2005 that focused on the nonclinical (S7B) and clinical (E14) assessment of surrogate biomarkers for TdP. Recently, Vargas et al. published a pharmaceutical-industry perspective making the case that "double-negative" nonclinical data (negative in vitro hERG and in vivo heart-rate corrected QT (QTc) assays) are associated with such low probability of clinical QTc prolongation and TdP that potentially all double-negative drugs would not need detailed clinical QTc evaluation. Subsequently, the ICH released a new E14/S7B Draft Guideline containing Questions and Answers (Q&As) that defined ways that double-negative nonclinical data could be used to reduce the number of "Thorough QT" (TQT) studies and reach a low-risk determination when a TQT or equivalent could not be performed. We review the Vargas et al. proposal in the context of what was contained in the ICH E14/S7B Draft Guideline and what was proposed by the ICH E14/S7B working group for a "stage 2" of updates (potential expanded roles for nonclinical data and details for assessing TdP risk of QTc-prolonging drugs). Although we do not agree with the exact probability statistics in the Vargas et al. paper because of limitations in the underlying datasets, we show how more modest predictive value of individual assays could still result in low probability for TdP with double-negative findings. Furthermore, we expect that the predictive value of the nonclinical assays will improve with implementation of the new ICH E14/S7B Draft Guideline.
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Affiliation(s)
- David G. Strauss
- Division of Applied Regulatory ScienceOffice of Clinical PharmacologyOffice of Translational SciencesCenter for Drug Evaluation and ResearchUS Food and Drug AdministrationSilver SpringMarylandUSA
| | - Wendy W. Wu
- Division of Applied Regulatory ScienceOffice of Clinical PharmacologyOffice of Translational SciencesCenter for Drug Evaluation and ResearchUS Food and Drug AdministrationSilver SpringMarylandUSA
| | - Zhihua Li
- Division of Applied Regulatory ScienceOffice of Clinical PharmacologyOffice of Translational SciencesCenter for Drug Evaluation and ResearchUS Food and Drug AdministrationSilver SpringMarylandUSA
| | - John Koerner
- Division of Pharm/Tox for Cardiology, Hematology, Endocrinology and NephrologyOffice of Cardiology, Hematology, Endocrinology and NephrologyOffice of New DrugsCenter for Drug Evaluation and ResearchUS Food and Drug AdministrationSilver SpringMarylandUSA
| | - Christine Garnett
- Division of Cardiology and NephrologyOffice of Cardiology, Hematology, Endocrinology and NephrologyOffice of New DrugsCenter for Drug Evaluation and ResearchUS Food and Drug AdministrationSilver SpringMarylandUSA
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7
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Han X, Samieegohar M, Ridder BJ, Wu WW, Randolph A, Tran P, Sheng J, Stoelzle-Feix S, Brinkwirth N, Rotordam MG, Becker N, Friis S, Rapedius M, Goetze TA, Strassmaier T, Okeyo G, Kramer J, Kuryshev Y, Wu C, Strauss DG, Li Z. A general procedure to select calibration drugs for lab-specific validation and calibration of proarrhythmia risk prediction models: An illustrative example using the CiPA model. J Pharmacol Toxicol Methods 2020; 105:106890. [PMID: 32574700 DOI: 10.1016/j.vascn.2020.106890] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 06/08/2020] [Accepted: 06/11/2020] [Indexed: 02/01/2023]
Abstract
INTRODUCTION In response to the ongoing shift of the regulatory cardiac safety paradigm, a recent White Paper proposed general principles for developing and implementing proarrhythmia risk prediction models. These principles included development strategies to validate models, and implementation strategies to ensure a model developed by one lab can be used by other labs in a consistent manner in the presence of lab-to-lab experimental variability. While the development strategies were illustrated through the validation of the model under the Comprehensive In vitro Proarrhythmia Assay (CiPA), the implementation strategies have not been adopted yet. METHODS The proposed implementation strategies were applied to the CiPA model by performing a sensitivity analysis to identify a subset of calibration drugs that were most critical in determining the classification thresholds for proarrhythmia risk prediction. RESULTS The selected calibration drugs were able to recapitulate classification thresholds close to those calculated from the full list of CiPA drugs. Using an illustrative dataset it was shown that a new lab could use these calibration drugs to establish its own classification thresholds (lab-specific calibration), and verify that the model prediction accuracy in the new lab is comparable to that in the original lab where the model was developed (lab-specific validation). DISCUSSION This work used the CiPA model as an example to illustrate how to adopt the proposed model implementation strategies to select calibration drugs and perform lab-specific calibration and lab-specific validation. Generic in nature, these strategies could be generally applied to different proarrhythmia risk prediction models using various experimental systems under the new paradigm.
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Affiliation(s)
- Xiaomei Han
- Division of Applied Regulatory Science, Office of Clinical Pharmacology, Office of Translational Sciences, Center for Drug Evaluation and Research, Food and Drug Administration, 10903 New Hampshire Ave, Silver Spring, MD 20993, United States
| | - Mohammadreza Samieegohar
- Division of Applied Regulatory Science, Office of Clinical Pharmacology, Office of Translational Sciences, Center for Drug Evaluation and Research, Food and Drug Administration, 10903 New Hampshire Ave, Silver Spring, MD 20993, United States
| | - Bradley J Ridder
- Division of Applied Regulatory Science, Office of Clinical Pharmacology, Office of Translational Sciences, Center for Drug Evaluation and Research, Food and Drug Administration, 10903 New Hampshire Ave, Silver Spring, MD 20993, United States
| | - Wendy W Wu
- Division of Applied Regulatory Science, Office of Clinical Pharmacology, Office of Translational Sciences, Center for Drug Evaluation and Research, Food and Drug Administration, 10903 New Hampshire Ave, Silver Spring, MD 20993, United States
| | - Aaron Randolph
- Division of Applied Regulatory Science, Office of Clinical Pharmacology, Office of Translational Sciences, Center for Drug Evaluation and Research, Food and Drug Administration, 10903 New Hampshire Ave, Silver Spring, MD 20993, United States
| | - Phu Tran
- Division of Applied Regulatory Science, Office of Clinical Pharmacology, Office of Translational Sciences, Center for Drug Evaluation and Research, Food and Drug Administration, 10903 New Hampshire Ave, Silver Spring, MD 20993, United States
| | - Jiansong Sheng
- CiPA LAB, 900 Clopper Rd, Suite 130, Gaithersburg, MD 20878, United States
| | | | - Nina Brinkwirth
- Nanion Technologies Munich, Ganghoferstrasse 70A, Munich, Germany
| | | | - Nadine Becker
- Nanion Technologies Munich, Ganghoferstrasse 70A, Munich, Germany
| | - Søren Friis
- Nanion Technologies Munich, Ganghoferstrasse 70A, Munich, Germany
| | - Markus Rapedius
- Nanion Technologies Munich, Ganghoferstrasse 70A, Munich, Germany
| | - Tom A Goetze
- Nanion Technologies Munich, Ganghoferstrasse 70A, Munich, Germany
| | - Tim Strassmaier
- Nanion Technologies USA, 1 Naylon Place, Suite C, Livingston, NJ 07039, United States
| | - George Okeyo
- Nanion Technologies USA, 1 Naylon Place, Suite C, Livingston, NJ 07039, United States
| | - James Kramer
- Charles River Laboratories, 14656 Neo Parkway, Cleveland, OH 44128, United States
| | - Yuri Kuryshev
- Charles River Laboratories, 14656 Neo Parkway, Cleveland, OH 44128, United States
| | - Caiyun Wu
- Charles River Laboratories, 14656 Neo Parkway, Cleveland, OH 44128, United States
| | - David G Strauss
- Division of Applied Regulatory Science, Office of Clinical Pharmacology, Office of Translational Sciences, Center for Drug Evaluation and Research, Food and Drug Administration, 10903 New Hampshire Ave, Silver Spring, MD 20993, United States
| | - Zhihua Li
- Division of Applied Regulatory Science, Office of Clinical Pharmacology, Office of Translational Sciences, Center for Drug Evaluation and Research, Food and Drug Administration, 10903 New Hampshire Ave, Silver Spring, MD 20993, United States.
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8
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Ridder BJ, Leishman DJ, Bridgland-Taylor M, Samieegohar M, Han X, Wu WW, Randolph A, Tran P, Sheng J, Danker T, Lindqvist A, Konrad D, Hebeisen S, Polonchuk L, Gissinger E, Renganathan M, Koci B, Wei H, Fan J, Levesque P, Kwagh J, Imredy J, Zhai J, Rogers M, Humphries E, Kirby R, Stoelzle-Feix S, Brinkwirth N, Rotordam MG, Becker N, Friis S, Rapedius M, Goetze TA, Strassmaier T, Okeyo G, Kramer J, Kuryshev Y, Wu C, Himmel H, Mirams GR, Strauss DG, Bardenet R, Li Z. A systematic strategy for estimating hERG block potency and its implications in a new cardiac safety paradigm. Toxicol Appl Pharmacol 2020; 394:114961. [PMID: 32209365 PMCID: PMC7166077 DOI: 10.1016/j.taap.2020.114961] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Revised: 02/14/2020] [Accepted: 03/19/2020] [Indexed: 12/13/2022]
Abstract
Introduction hERG block potency is widely used to calculate a drug's safety margin against its torsadogenic potential. Previous studies are confounded by use of different patch clamp electrophysiology protocols and a lack of statistical quantification of experimental variability. Since the new cardiac safety paradigm being discussed by the International Council for Harmonisation promotes a tighter integration of nonclinical and clinical data for torsadogenic risk assessment, a more systematic approach to estimate the hERG block potency and safety margin is needed. Methods A cross-industry study was performed to collect hERG data on 28 drugs with known torsadogenic risk using a standardized experimental protocol. A Bayesian hierarchical modeling (BHM) approach was used to assess the hERG block potency of these drugs by quantifying both the inter-site and intra-site variability. A modeling and simulation study was also done to evaluate protocol-dependent changes in hERG potency estimates. Results A systematic approach to estimate hERG block potency is established. The impact of choosing a safety margin threshold on torsadogenic risk evaluation is explored based on the posterior distributions of hERG potency estimated by this method. The modeling and simulation results suggest any potency estimate is specific to the protocol used. Discussion This methodology can estimate hERG block potency specific to a given voltage protocol. The relationship between safety margin thresholds and torsadogenic risk predictivity suggests the threshold should be tailored to each specific context of use, and safety margin evaluation may need to be integrated with other information to form a more comprehensive risk assessment. hERG potency/safety margin is a widely used nonclinical cardiac safety strategy. A new regulatory paradigm promotes the integration of nonclinical and clinical data. Lack of uncertainty quantification hindered using hERG potency in the new paradigm. A systematic method was established to address this limitation. Analysis supports using different safety margin thresholds in different context.
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Affiliation(s)
- Bradley J Ridder
- Division of Applied Regulatory Science, Office of Clinical Pharmacology, Office of Translational Sciences, Center for Drug Evaluation and Research, Food and Drug Administration, 10903 New Hampshire Ave, Silver Spring, MD 20993, USA
| | - Derek J Leishman
- Department of Toxicology and Pathology, Eli Lilly and Company, Indianapolis, IN, USA
| | | | - Mohammadreza Samieegohar
- Division of Applied Regulatory Science, Office of Clinical Pharmacology, Office of Translational Sciences, Center for Drug Evaluation and Research, Food and Drug Administration, 10903 New Hampshire Ave, Silver Spring, MD 20993, USA
| | - Xiaomei Han
- Division of Applied Regulatory Science, Office of Clinical Pharmacology, Office of Translational Sciences, Center for Drug Evaluation and Research, Food and Drug Administration, 10903 New Hampshire Ave, Silver Spring, MD 20993, USA
| | - Wendy W Wu
- Division of Applied Regulatory Science, Office of Clinical Pharmacology, Office of Translational Sciences, Center for Drug Evaluation and Research, Food and Drug Administration, 10903 New Hampshire Ave, Silver Spring, MD 20993, USA
| | - Aaron Randolph
- Division of Applied Regulatory Science, Office of Clinical Pharmacology, Office of Translational Sciences, Center for Drug Evaluation and Research, Food and Drug Administration, 10903 New Hampshire Ave, Silver Spring, MD 20993, USA
| | - Phu Tran
- Division of Applied Regulatory Science, Office of Clinical Pharmacology, Office of Translational Sciences, Center for Drug Evaluation and Research, Food and Drug Administration, 10903 New Hampshire Ave, Silver Spring, MD 20993, USA
| | - Jiansong Sheng
- CiPA LAB, 900 Clopper Rd, Suite 130, Gaithersburg, MD 20878, USA
| | - Timm Danker
- NMI-TT GmbH, Markwiesenstr. 55, 72770 Reutlingen, Germany
| | | | - Daniel Konrad
- B'SYS GmbH, The Ion Channel Company, Benkenstrasse 254, CH-4108, Witterswil, Switzerland
| | - Simon Hebeisen
- B'SYS GmbH, The Ion Channel Company, Benkenstrasse 254, CH-4108, Witterswil, Switzerland
| | - Liudmila Polonchuk
- F. Hoffmann-La Roche AG, F. Hoffmann-La Roche Ltd Bldg. 73/R. 103b Grenzacherstrasse, 124, CH-4070 Basel, Switzerland
| | - Evgenia Gissinger
- F. Hoffmann-La Roche AG, F. Hoffmann-La Roche Ltd Bldg. 73/R. 103b Grenzacherstrasse, 124, CH-4070 Basel, Switzerland
| | | | - Bryan Koci
- Eurofins Scientific, Eurofins Discovery, 6 Research Park Drive, St. Charles, MO 63304, USA
| | - Haiyang Wei
- Eurofins Scientific, Eurofins Discovery, 6 Research Park Drive, St. Charles, MO 63304, USA
| | - Jingsong Fan
- Bristol-Myers Squibb Company, Discovery Toxicology, Bristol-Myers Squibb, 3551 Lawrenceville, Princeton Rd, Lawrence Township, NJ 08648, USA
| | - Paul Levesque
- Bristol-Myers Squibb Company, Discovery Toxicology, Bristol-Myers Squibb, 3551 Lawrenceville, Princeton Rd, Lawrence Township, NJ 08648, USA
| | - Jae Kwagh
- Bristol-Myers Squibb Company, Discovery Toxicology, Bristol-Myers Squibb, 3551 Lawrenceville, Princeton Rd, Lawrence Township, NJ 08648, USA
| | | | - Jin Zhai
- Merck & Co., Inc, Kenilworth, NJ, USA
| | - Marc Rogers
- Metrion Biosciences Limited, Riverside 3, Suite 1, Granta Park, Great Abington, Cambridge CB21, 6AD, United Kingdom
| | - Edward Humphries
- Metrion Biosciences Limited, Riverside 3, Suite 1, Granta Park, Great Abington, Cambridge CB21, 6AD, United Kingdom
| | - Robert Kirby
- Metrion Biosciences Limited, Riverside 3, Suite 1, Granta Park, Great Abington, Cambridge CB21, 6AD, United Kingdom
| | | | - Nina Brinkwirth
- Nanion Technologies Munich, Ganghoferstrasse 70A, 80339 Munich, Germany
| | | | - Nadine Becker
- Nanion Technologies Munich, Ganghoferstrasse 70A, 80339 Munich, Germany
| | - Søren Friis
- Nanion Technologies Munich, Ganghoferstrasse 70A, 80339 Munich, Germany
| | - Markus Rapedius
- Nanion Technologies Munich, Ganghoferstrasse 70A, 80339 Munich, Germany
| | - Tom A Goetze
- Nanion Technologies Munich, Ganghoferstrasse 70A, 80339 Munich, Germany
| | - Tim Strassmaier
- Nanion Technologies, USA, 1 Naylon Place, Suite C, Livingston, NJ 07039, USA
| | - George Okeyo
- Nanion Technologies, USA, 1 Naylon Place, Suite C, Livingston, NJ 07039, USA
| | - James Kramer
- Charles River Laboratories, 14656 Neo Parkway, Cleveland, OH 44128, USA
| | - Yuri Kuryshev
- Charles River Laboratories, 14656 Neo Parkway, Cleveland, OH 44128, USA
| | - Caiyun Wu
- Charles River Laboratories, 14656 Neo Parkway, Cleveland, OH 44128, USA
| | - Herbert Himmel
- Bayer AG, RD-TS-TOX-SP-SPL1, Aprather Weg 18a, 42096 Wuppertal, Germany
| | - Gary R Mirams
- Centre for Mathematical Medicine & Biology, School of Mathematical Sciences, University of Nottingham, Nottingham, United Kingdom
| | - David G Strauss
- Division of Applied Regulatory Science, Office of Clinical Pharmacology, Office of Translational Sciences, Center for Drug Evaluation and Research, Food and Drug Administration, 10903 New Hampshire Ave, Silver Spring, MD 20993, USA
| | - Rémi Bardenet
- Université de Lille, CNRS, Centrale Lille, UMR 9189 - CRIStAL, Villeneuve d'Ascq, France
| | - Zhihua Li
- Division of Applied Regulatory Science, Office of Clinical Pharmacology, Office of Translational Sciences, Center for Drug Evaluation and Research, Food and Drug Administration, 10903 New Hampshire Ave, Silver Spring, MD 20993, USA.
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9
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Li Z, Mirams GR, Yoshinaga T, Ridder BJ, Han X, Chen JE, Stockbridge NL, Wisialowski TA, Damiano B, Severi S, Morissette P, Kowey PR, Holbrook M, Smith G, Rasmusson RL, Liu M, Song Z, Qu Z, Leishman DJ, Steidl‐Nichols J, Rodriguez B, Bueno‐Orovio A, Zhou X, Passini E, Edwards AG, Morotti S, Ni H, Grandi E, Clancy CE, Vandenberg J, Hill A, Nakamura M, Singer T, Polonchuk L, Greiter‐Wilke A, Wang K, Nave S, Fullerton A, Sobie EA, Paci M, Musuamba Tshinanu F, Strauss DG. General Principles for the Validation of Proarrhythmia Risk Prediction Models: An Extension of the CiPA In Silico Strategy. Clin Pharmacol Ther 2020; 107:102-111. [PMID: 31709525 PMCID: PMC6977398 DOI: 10.1002/cpt.1647] [Citation(s) in RCA: 53] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Accepted: 09/06/2019] [Indexed: 12/27/2022]
Abstract
This white paper presents principles for validating proarrhythmia risk prediction models for regulatory use as discussed at the In Silico Breakout Session of a Cardiac Safety Research Consortium/Health and Environmental Sciences Institute/US Food and Drug Administration-sponsored Think Tank Meeting on May 22, 2018. The meeting was convened to evaluate the progress in the development of a new cardiac safety paradigm, the Comprehensive in Vitro Proarrhythmia Assay (CiPA). The opinions regarding these principles reflect the collective views of those who participated in the discussion of this topic both at and after the breakout session. Although primarily discussed in the context of in silico models, these principles describe the interface between experimental input and model-based interpretation and are intended to be general enough to be applied to other types of nonclinical models for proarrhythmia assessment. This document was developed with the intention of providing a foundation for more consistency and harmonization in developing and validating different models for proarrhythmia risk prediction using the example of the CiPA paradigm.
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10
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Zhao P, Li P. Transmural and rate-dependent profiling of drug-induced arrhythmogenic risks through in silico simulations of multichannel pharmacology. Sci Rep 2019; 9:18504. [PMID: 31811197 PMCID: PMC6898675 DOI: 10.1038/s41598-019-55032-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Accepted: 11/21/2019] [Indexed: 01/08/2023] Open
Abstract
In vitro human ether-à-go-go related gene (hERG) inhibition assay alone might provide insufficient information to discriminate "safe" from "dangerous" drugs. Here, effects of multichannel inhibition on cardiac electrophysiology were investigated using a family of cardiac cell models (Purkinje (P), endocardial (Endo), mid-myocardial (M) and epicardial (Epi)). We found that: (1) QT prolongation alone might not necessarily lead to early afterdepolarization (EAD) events, and it might be insufficient to predict arrhythmogenic liability; (2) the occurrence and onset of EAD events could be a candidate biomarker of drug-induced arrhythmogenicity; (3) M cells are more vulnerable to drug-induced arrhythmias, and can develop early afterdepolarization (EAD) at slower pacing rates; (4) the application of quinidine can cause EADs in all cell types, while INaL is the major depolarizing current during the generation of drug-induced EAD in P cells, ICaL is mostly responsible in other cell types; (5) drug-induced action potential (AP) alternans with beat-to-beat variations occur at high pacing rates in P cells. These results suggested that quantitative profiling of transmural and rate-dependent properties can be essential to evaluate drug-induced arrhythmogenic risks, and may provide mechanistic insights into drug-induced arrhythmias.
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Affiliation(s)
- Ping'an Zhao
- Center for Public Health Informatics, School of Public Health, Xinxiang Medical University, Henan, P.R. China
- Center for Biomedical Innovation, Yunmai Biomedical Research Institute, Henan, P.R. China
| | - Pan Li
- Center for Public Health Informatics, School of Public Health, Xinxiang Medical University, Henan, P.R. China.
- Center for Biomedical Innovation, Yunmai Biomedical Research Institute, Henan, P.R. China.
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11
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Passini E, Trovato C, Morissette P, Sannajust F, Bueno‐Orovio A, Rodriguez B. Drug-induced shortening of the electromechanical window is an effective biomarker for in silico prediction of clinical risk of arrhythmias. Br J Pharmacol 2019; 176:3819-3833. [PMID: 31271649 PMCID: PMC6780030 DOI: 10.1111/bph.14786] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Revised: 05/21/2019] [Accepted: 06/28/2019] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND AND PURPOSE Early identification of drug-induced cardiac adverse events is key in drug development. Human-based computer models are emerging as an effective approach, complementary to in vitro and animal models. Drug-induced shortening of the electromechanical window has been associated with increased risk of arrhythmias. This study investigates the potential of a cellular surrogate for the electromechanical window (EMw) for prediction of pro-arrhythmic cardiotoxicity, and its underlying ionic mechanisms, using human-based computer models. EXPERIMENTAL APPROACH In silico drug trials for 40 reference compounds were performed, testing up to 100-fold the therapeutic concentrations (EFTPCmax ) and using a control population of human ventricular action potential (AP) models, optimised to capture pro-arrhythmic ionic profiles. EMw was calculated for each model in the population as the difference between AP and Ca2+ transient durations at 90%. Drug-induced changes in the EMw and occurrence of repolarisation abnormalities (RA) were quantified. KEY RESULTS Drugs with clinical risk of Torsade de Pointes arrhythmias induced a concentration-dependent EMw shortening, while safe drugs lead to increase or small change in EMw. Risk predictions based on EMw shortening achieved 90% accuracy at 10× EFTPCmax , whereas RA-based predictions required 100× EFTPCmax to reach the same accuracy. As it is dependent on Ca2+ transient, the EMw was also more sensitive than AP prolongation in distinguishing between pure hERG blockers and multichannel compounds also blocking the calcium current. CONCLUSION AND IMPLICATIONS The EMw is an effective biomarker for in silico predictions of drug-induced clinical pro-arrhythmic risk, particularly for compounds with multichannel blocking action.
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Affiliation(s)
- Elisa Passini
- Department of Computer ScienceUniversity of OxfordOxfordUK
| | | | - Pierre Morissette
- SALAR, Safety and Exploratory Pharmacology Department, Merck Research LaboratoriesMerck & Co., Inc.West PointPAUSA
| | - Frederick Sannajust
- SALAR, Safety and Exploratory Pharmacology Department, Merck Research LaboratoriesMerck & Co., Inc.West PointPAUSA
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Park E, Gintant GA, Bi D, Kozeli D, Pettit SD, Pierson JB, Skinner M, Willard J, Wisialowski T, Koerner J, Valentin JP. Can non-clinical repolarization assays predict the results of clinical thorough QT studies? Results from a research consortium. Br J Pharmacol 2018; 175:606-617. [PMID: 29181850 PMCID: PMC5786459 DOI: 10.1111/bph.14101] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2016] [Revised: 10/12/2017] [Accepted: 11/13/2017] [Indexed: 01/06/2023] Open
Abstract
Background and Purpose Translation of non‐clinical markers of delayed ventricular repolarization to clinical prolongation of the QT interval corrected for heart rate (QTc) (a biomarker for torsades de pointes proarrhythmia) remains an issue in drug discovery and regulatory evaluations. We retrospectively analysed 150 drug applications in a US Food and Drug Administration database to determine the utility of established non‐clinical in vitro IKr current human ether‐à‐go‐go‐related gene (hERG), action potential duration (APD) and in vivo (QTc) repolarization assays to detect and predict clinical QTc prolongation. Experimental Approach The predictive performance of three non‐clinical assays was compared with clinical thorough QT study outcomes based on free clinical plasma drug concentrations using sensitivity and specificity, receiver operating characteristic (ROC) curves, positive (PPVs) and negative predictive values (NPVs) and likelihood ratios (LRs). Key Results Non‐clinical assays demonstrated robust specificity (high true negative rate) but poor sensitivity (low true positive rate) for clinical QTc prolongation at low‐intermediate (1×–30×) clinical exposure multiples. The QTc assay provided the most robust PPVs and NPVs (ability to predict clinical QTc prolongation). ROC curves (overall test accuracy) and LRs (ability to influence post‐test probabilities) demonstrated overall marginal performance for hERG and QTc assays (best at 30× exposures), while the APD assay demonstrated minimal value. Conclusions and Implications The predictive value of hERG, APD and QTc assays varies, with drug concentrations strongly affecting translational performance. While useful in guiding preclinical candidates without clinical QT prolongation, hERG and QTc repolarization assays provide greater value compared with the APD assay.
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Affiliation(s)
- Eunjung Park
- Center for Drug Evaluation and Research, US FDA, Silver Spring, MD, USA
| | - Gary A Gintant
- Department of Integrative Pharmacology, AbbVie, North Chicago, IL, USA
| | - Daoqin Bi
- Center for Drug Evaluation and Research, US FDA, Silver Spring, MD, USA
| | - Devi Kozeli
- Center for Drug Evaluation and Research, US FDA, Silver Spring, MD, USA
| | | | | | - Matthew Skinner
- Drug Safety and Metabolism, AstraZeneca, Macclesfield, Cheshire, UK
| | - James Willard
- Center for Drug Evaluation and Research, US FDA, Silver Spring, MD, USA
| | | | - John Koerner
- Center for Drug Evaluation and Research, US FDA, Silver Spring, MD, USA
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Parikh J, Gurev V, Rice JJ. Novel Two-Step Classifier for Torsades de Pointes Risk Stratification from Direct Features. Front Pharmacol 2017; 8:816. [PMID: 29184497 PMCID: PMC5694470 DOI: 10.3389/fphar.2017.00816] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Accepted: 10/27/2017] [Indexed: 12/16/2022] Open
Abstract
While pre-clinical Torsades de Pointes (TdP) risk classifiers had initially been based on drug-induced block of hERG potassium channels, it is now well established that improved risk prediction can be achieved by considering block of non-hERG ion channels. The current multi-channel TdP classifiers can be categorized into two classes. First, the classifiers that take as input the values of drug-induced block of ion channels (direct features). Second, the classifiers that are built on features extracted from output of the drug-induced multi-channel blockage simulations in the in-silico models (derived features). The classifiers built on derived features have thus far not consistently provided increased prediction accuracies, and hence casts doubt on the value of such approaches given the cost of including biophysical detail. Here, we propose a new two-step method for TdP risk classification, referred to as Multi-Channel Blockage at Early After Depolarization (MCB@EAD). In the first step, we classified the compound that produced insufficient hERG block as non-torsadogenic. In the second step, the role of non-hERG channels to modulate TdP risk are considered by constructing classifiers based on direct or derived features at critical hERG block concentrations that generates EADs in the computational cardiac cell models. MCB@EAD provides comparable or superior TdP risk classification of the drugs from the direct features in tests against published methods. TdP risk for the drugs highly correlated to the propensity to generate EADs in the model. However, the derived features of the biophysical models did not improve the predictive capability for TdP risk assessment.
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Affiliation(s)
| | | | - John J. Rice
- IBM T. J. Watson Research Center, Yorktown Heights, NY, United States
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14
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Wiśniowska B, Polak S. Am I or am I not proarrhythmic? Comparison of various classifications of drug TdP propensity. Drug Discov Today 2017; 22:10-16. [DOI: 10.1016/j.drudis.2016.09.027] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2016] [Revised: 08/22/2016] [Accepted: 09/28/2016] [Indexed: 12/12/2022]
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Inter-individual variability and modeling of electrical activity: a possible new approach to explore cardiac safety? Sci Rep 2016; 6:37948. [PMID: 27901061 PMCID: PMC5128803 DOI: 10.1038/srep37948] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Accepted: 11/02/2016] [Indexed: 11/08/2022] Open
Abstract
Safety pharmacology aims to predict rare side effects of new drugs. We explored whether rare pro-arrhythmic effects could be linked to the variability of the effects of these drugs on ion currents and whether taking into consideration this variability in computational models could help to better detect and predict cardiac side effects. For this purpose, we evaluated how intra- and inter-individual variability influences the effect of hERG inhibition on both the action potential duration and the occurrence of arrhythmias. Using two computer simulation models of human action potentials (endocardial and Purkinje cells), we analyzed the contribution of two biological parameters on the pro-arrhythmic effects of several hERG channel blockers: (i) spermine concentration, which varies with metabolic status, and (ii) L-type calcium conductance, which varies due to single nucleotide polymorphisms or mutations. By varying these parameters, we were able to induce arrhythmias in 1 out of 16 simulations although conventional modeling methods to detect pro-arrhythmic molecules failed. On the basis of our results, taking into consideration only 2 parameters subjected to intra- and inter-individual variability, we propose that in silico computer modeling may help to better define the risks of new drug candidates at early stages of pre-clinical development.
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16
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Lancaster MC, Sobie EA. Improved Prediction of Drug-Induced Torsades de Pointes Through Simulations of Dynamics and Machine Learning Algorithms. Clin Pharmacol Ther 2016; 100:371-9. [PMID: 26950176 DOI: 10.1002/cpt.367] [Citation(s) in RCA: 86] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2015] [Revised: 02/15/2016] [Accepted: 03/03/2016] [Indexed: 12/21/2022]
Abstract
The ventricular arrhythmia Torsades de Pointes (TdP) is a common form of drug-induced cardiotoxicity, but prediction of this arrhythmia remains an unresolved issue in drug development. Current assays to evaluate arrhythmia risk are limited by poor specificity and a lack of mechanistic insight. We addressed this important unresolved issue through a novel computational approach that combined simulations of drug effects on dynamics with statistical analysis and machine-learning. Drugs that blocked multiple ion channels were simulated in ventricular myocyte models, and metrics computed from the action potential and intracellular (Ca(2+) ) waveform were used to construct classifiers that distinguished between arrhythmogenic and nonarrhythmogenic drugs. We found that: (1) these classifiers provide superior risk prediction; (2) drug-induced changes to both the action potential and intracellular (Ca(2+) ) influence risk; and (3) cardiac ion channels not typically assessed may significantly affect risk. Our algorithm demonstrates the value of systematic simulations in predicting pharmacological toxicity.
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Affiliation(s)
- M Cummins Lancaster
- Department of Pharmacology and Systems Therapeutics, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - E A Sobie
- Department of Pharmacology and Systems Therapeutics, Icahn School of Medicine at Mount Sinai, New York, New York, USA.
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17
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Disturbances of cardiac wavelength and repolarization precede Torsade de Pointes and ventricular fibrillation in Langendorff perfused rabbit hearts. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2016; 121:3-10. [DOI: 10.1016/j.pbiomolbio.2016.03.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2016] [Revised: 03/04/2016] [Accepted: 03/10/2016] [Indexed: 11/20/2022]
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18
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Champeroux P, Le Guennec JY, Jude S, Laigot C, Maurin A, Sola ML, Fowler JSL, Richard S, Thireau J. The high frequency relationship: implications for torsadogenic hERG blockers. Br J Pharmacol 2016; 173:601-12. [PMID: 26589499 DOI: 10.1111/bph.13391] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Revised: 11/11/2015] [Accepted: 11/17/2015] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND AND PURPOSE Ventricular arrhythmias induced by human ether-a-go-go related gene (hERG; Kv 11.1 channel) blockers are a consequence of alterations in ventricular repolarisation in association with high-frequency (HF) oscillations, which act as a primary trigger; the autonomic nervous system plays a modulatory role. In the present study, we investigated the role of β1 -adrenoceptors in the HF relationship between magnitude of heart rate and QT interval changes within discrete 10 s intervals (sorted into 5 bpm heart rate increments) and its implications for torsadogenic hERG blockers. EXPERIMENTAL APPROACH The HF relationship was studied under conditions of autonomic blockade with atenolol (β1 -adrenoceptor blocker) in the absence or presence of five hERG blockers in beagle dogs. In total, the effects of 14 hERG blockers on the HF relationship were investigated. KEY RESULTS All the torsadogenic hERG blockers tested caused a vertical shift in the HF relationship, while hERG blockers associated with a low risk of Torsades de Pointes did not cause any vertical shift. Atenolol completely prevented the effects four torsadogenic agents (quinidine, thioridazine, risperidone and terfenadine) on the HF relationship, but only partially reduced those of dofetilide, leading to the characterization of two types of torsadogenic agent. CONCLUSIONS AND IMPLICATIONS Analysis of the vertical shift in the HF relationship demonstrated that signs of transient sympathetic activation during HF oscillations in the presence of torsadogenic hERG blockers are mediated by β1 -adrenoceptors. We suggest the HF relationship as a new biomarker for assessing Torsades de pointes liability, with potential implications in both preclinical studies and the clinic.
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Affiliation(s)
- P Champeroux
- Centre de Recherches Biologiques, CERB, Chemin de Montifault, 18800, Baugy, France
| | - J Y Le Guennec
- Laboratoire PHYMEDEXP, Physiologie et Médecine Expérimentale, Cœur et Muscles, INSERM U1046, CNRS UMR 9214, Université de Montpellier, CHU Arnaud de Villeneuve, 371 Avenue du doyen G. Giraud, 34295, Montpellier cedex 05, France
| | - S Jude
- Centre de Recherches Biologiques, CERB, Chemin de Montifault, 18800, Baugy, France
| | - C Laigot
- Centre de Recherches Biologiques, CERB, Chemin de Montifault, 18800, Baugy, France
| | - A Maurin
- Centre de Recherches Biologiques, CERB, Chemin de Montifault, 18800, Baugy, France
| | - M L Sola
- Centre de Recherches Biologiques, CERB, Chemin de Montifault, 18800, Baugy, France
| | - J S L Fowler
- Centre de Recherches Biologiques, CERB, Chemin de Montifault, 18800, Baugy, France
| | - S Richard
- Centre de Recherches Biologiques, CERB, Chemin de Montifault, 18800, Baugy, France
| | - J Thireau
- Laboratoire PHYMEDEXP, Physiologie et Médecine Expérimentale, Cœur et Muscles, INSERM U1046, CNRS UMR 9214, Université de Montpellier, CHU Arnaud de Villeneuve, 371 Avenue du doyen G. Giraud, 34295, Montpellier cedex 05, France
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19
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Lee HA, Hyun SA, Park SG, Kim KS, Kim SJ. Comparison of electrophysiological effects of calcium channel blockers on cardiac repolarization. THE KOREAN JOURNAL OF PHYSIOLOGY & PHARMACOLOGY : OFFICIAL JOURNAL OF THE KOREAN PHYSIOLOGICAL SOCIETY AND THE KOREAN SOCIETY OF PHARMACOLOGY 2015; 20:119-27. [PMID: 26807031 PMCID: PMC4722185 DOI: 10.4196/kjpp.2016.20.1.119] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/26/2015] [Revised: 11/05/2015] [Accepted: 11/05/2015] [Indexed: 12/13/2022]
Abstract
Dihydropyridine (DHP) calcium channel blockers (CCBs) have been widely used to treat of several cardiovascular diseases. An excessive shortening of action potential duration (APD) due to the reduction of Ca2+ channel current (ICa) might increase the risk of arrhythmia. In this study we investigated the electrophysiological effects of nicardipine (NIC), isradipine (ISR), and amlodipine (AML) on the cardiac APD in rabbit Purkinje fibers, voltage-gated K+ channel currents (IKr, IKs) and voltage-gated Na+ channel current (INa). The concentration-dependent inhibition of Ca2+ channel currents (ICa) was examined in rat cardiomyocytes; these CCBs have similar potency on ICa channel blocking with IC50 (the half-maximum inhibiting concentration) values of 0.142, 0.229, and 0.227 nM on NIC, ISR, and AML, respectively. However, ISR shortened both APD50 and APD90 already at 1 µM whereas NIC and AML shortened APD50 but not APD90 up to 30 µM. According to ion channel studies, NIC and AML concentration-dependently inhibited IKr and IKs while ISR had only partial inhibitory effects (<50% at 30 µM). Inhibition of INa was similarly observed in the three CCBs. Since the IKr and IKs mainly contribute to cardiac repolarization, their inhibition by NIC and AML could compensate for the AP shortening effects due to the block of ICa.
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Affiliation(s)
- Hyang-Ae Lee
- Next-generation Pharmaceutical Research Center, Korea Institute of Toxicology, Daejeon 34114, Korea.; Department of Physiology, Seoul National University College of Medicine, Seoul 03080, Korea.; Human and Environmental Toxicology Program, University of Science and Technology, Daejeon 34113, Korea
| | - Sung-Ae Hyun
- Next-generation Pharmaceutical Research Center, Korea Institute of Toxicology, Daejeon 34114, Korea
| | - Sung-Gurl Park
- Next-generation Pharmaceutical Research Center, Korea Institute of Toxicology, Daejeon 34114, Korea
| | - Ki-Suk Kim
- Next-generation Pharmaceutical Research Center, Korea Institute of Toxicology, Daejeon 34114, Korea.; Human and Environmental Toxicology Program, University of Science and Technology, Daejeon 34113, Korea
| | - Sung Joon Kim
- Department of Physiology, Seoul National University College of Medicine, Seoul 03080, Korea
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20
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Pugsley MK, Curtis MJ, Hayes ES. Biophysics and Molecular Biology of Cardiac Ion Channels for the Safety Pharmacologist. Handb Exp Pharmacol 2015; 229:149-203. [PMID: 26091640 DOI: 10.1007/978-3-662-46943-9_7] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Cardiac safety pharmacology is a continuously evolving discipline that uses the basic principles of pharmacology in a regulatory-driven process to generate data to inform risk/benefit assessment of a new chemical entity (NCE). The aim of cardiac safety pharmacology is to characterise the pharmacodynamic/pharmacokinetic (PK/PD) relationship of a drug's adverse effects on the heart using continuously evolving methodology. Unlike Toxicology, safety pharmacology includes within its remit a regulatory requirement to predict the risk of rare cardiotoxic (potentially lethal) events such as torsades de pointes (TdP), which is statistically associated with drug-induced changes in the QT interval of the ECG due to blockade of I Kr or K v11.1 current encoded by hERG. This gives safety pharmacology its unique character. The key issues for the safety pharmacology assessment of a drug on the heart are detection of an adverse effect liability, projection of the data into safety margin calculation and clinical safety monitoring. This chapter will briefly review the current cardiac safety pharmacology paradigm outlined in the ICH S7A and ICH S7B guidance documents and the non-clinical models and methods used in the evaluation of new chemical entities in order to define the integrated risk assessment for submission to regulatory authorities. An overview of how the present cardiac paradigm was developed will be discussed, explaining how it was based upon marketing authorisation withdrawal of many non-cardiovascular compounds due to unanticipated proarrhythmic effects. The role of related biomarkers (of cardiac repolarisation, e.g. prolongation of the QT interval of the ECG) will be considered. We will also provide an overview of the 'non-hERG-centric' concepts utilised in the evolving comprehensive in vitro proarrhythmia assay (CIPA) that details conduct of the proposed ion channel battery test, use of human stem cells and application of in silico models to early cardiac safety assessment. The summary of our current understanding of the triggers of TdP will include the interplay between action potential (AP) prolongation, early and delayed afterdepolarisation and substrates for re-entry arrhythmias.
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Affiliation(s)
- Michael K Pugsley
- Global Safety Pharmacology and Toxicology/Pathology, Janssen Pharmaceuticals LLC, 1000 Route 202 South, Raritan, NJ, 08869, USA,
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21
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Gibson JK, Yue Y, Bronson J, Palmer C, Numann R. Human stem cell-derived cardiomyocytes detect drug-mediated changes in action potentials and ion currents. J Pharmacol Toxicol Methods 2014; 70:255-67. [DOI: 10.1016/j.vascn.2014.09.005] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2014] [Revised: 09/02/2014] [Accepted: 09/04/2014] [Indexed: 10/24/2022]
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22
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Zhang J, Huan J. Predicting Drug-Induced QT Prolongation Effects Using Multi-View Learning. IEEE Trans Nanobioscience 2013; 12:206-13. [DOI: 10.1109/tnb.2013.2263511] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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23
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Ferro F, Ouillé A, Tran TA, Fontanaud P, Bois P, Babuty D, Labarthe F, Le Guennec JY. Long-chain acylcarnitines regulate the hERG channel. PLoS One 2012; 7:e41686. [PMID: 22848566 PMCID: PMC3404973 DOI: 10.1371/journal.pone.0041686] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2012] [Accepted: 06/25/2012] [Indexed: 12/30/2022] Open
Abstract
Background and purpose In some pathological conditions carnitine concentration is high while in othersitis low.In bothcases,cardiac arrhythmiascan occur and lead to sudden cardiac death. It has been proposed that in ischaemia, acylcarnitine (acyl-CAR), but not carnitine, is involved in arrhythmiasthrough modulation of ionic currents. We studied the effects of acyl-CARs on hERG, KIR2.1 and Kv7.1/minKchannels (channels responsible for IKR, IK1 and IKS respectively). Experimental approach HEK293 cells stably expressing hERG, KIR2.1 or Kv7.1/minK were studied using the patch clamp technique. Free carnitine (CAR) and acyl-CAR derivatives from medium- (C8 and C10) and long-chain (C16 and C18∶1) fatty acids were applied intra- and extracellularly at different concentrations. Forstudies onhERG, C16 and C18∶1 free fatty acid were also used. Key results Extracellular long-chain (LCAC), but not medium-chain, acyl-CAR,induced an increase of IhERG amplitude associated with a dose-dependent speeding of deactivation kinetics. They had no effect on KIR2.1 or Kv7.1/minK currents.Computer simulations of these effects wereconsistent with changes in action potential profile. Conclusions and applications Extracellular LCAC tonically regulates IhERG amplitude and kineticsunder physiological conditions. This modulation maycontribute tothe changes in action potential duration thatprecede cardiac arrhythmias in ischaemia, diabetes and primary systemic carnitine deficiency.
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Affiliation(s)
- Fabio Ferro
- INSERM U921, Université François-Rabelais, Tours, France
| | - Aude Ouillé
- INSERM U1046, Université Montpellier-1, Université Montpellier-2, Montpellier, France
- * E-mail:
| | - Truong-An Tran
- INSERM U921, Université François-Rabelais, Tours, France
| | - Pierre Fontanaud
- IGF-CNRS INSERM 661, Université Montpellier-1, Université Montpellier-2, Montpellier, France
| | - Patrick Bois
- IPBC, UMR 6187, CNRS, Université de Poitiers, Poitiers, France
| | - Dominique Babuty
- CHRU Tours, Hôpital Trousseau, Service de cardiologie B, Tours, France
| | | | - Jean-Yves Le Guennec
- INSERM U1046, Université Montpellier-1, Université Montpellier-2, Montpellier, France
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In vitro cardiovascular effects of dihydroartemisin-piperaquine combination compared with other antimalarials. Antimicrob Agents Chemother 2012; 56:3261-70. [PMID: 22391528 DOI: 10.1128/aac.05688-11] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
The in vitro cardiac properties of dihydroartemisinin (DHA) plus piperaquine phosphate (PQP) were compared with those of other antimalarial compounds. Results with antimalarial drugs, chosen on the basis of their free therapeutic maximum concentration in plasma (C(max)), were expressed as the fold of that particular effect with respect to their C(max). The following tests were used at 37 °C: hERG (human ether-à-go-go-related gene) blockade and trafficking, rabbit heart ventricular preparations, and sodium and slow potassium ion current interference (I(Na) and I(Ks), respectively). Chloroquine, halofantrine, mefloquine, and lumefantrine were tested in the hERG studies, but only chloroquine, dofetilide, lumefantrine, and the combination of artemether-lumefantrine were used in the rabbit heart ventricular preparations, hERG trafficking studies, and I(Na) and I(Ks) analyses. A proper reference was used in each test. In hERG studies, the high 50% inhibitory concentration (IC(50)) of halofantrine, which was lower than its C(max), was confirmed. All the other compounds blocked hERG, with IC(50)s ranging from 3- to 30-fold their C(max)s. In hERG trafficking studies, the facilitative effects of chloroquine at about 30-fold its C(max) were confirmed and DHA blocked it at a concentration about 300-fold its C(max). In rabbit heart ventricular preparations, dofetilide, used as a positive control, revealed a high risk of torsades de pointes, whereas chloroquine showed a medium risk. Neither DHA-PQP nor artemether-lumefantrine displayed an in vitro signal for a significant proarrhythmic risk. Only chloroquine blocked the I(Na) ion current and did so at about 30-fold its C(max). No effect on I(Ks) was detected. In conclusion, despite significant hERG blockade, DHA-PQP and artemether-lumefantrine do not appear to induce potential torsadogenic effects in vitro, affect hERG trafficking, or block sodium and slow potassium ion currents.
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Guo X, Gao X, Wang Y, Peng L, Zhu Y, Wang S. IKs protects from ventricular arrhythmia during cardiac ischemia and reperfusion in rabbits by preserving the repolarization reserve. PLoS One 2012; 7:e31545. [PMID: 22384037 PMCID: PMC3285162 DOI: 10.1371/journal.pone.0031545] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2011] [Accepted: 01/10/2012] [Indexed: 11/26/2022] Open
Abstract
Introduction The function of the repolarization reserve in the prevention of ventricular arrhythmias during cardiac ischemia/reperfusion and the impact of ischemia on slowly activated delayed rectifier potassium current (IKs) channel subunit expression are not well understood. Methods and Results The responses of monophasic action potential duration (MAPD) prolongation and triangulation were investigated following an L-768,673-induced blockade of IKs with or without ischemia/reperfusion in a rabbit model of left circumflex coronary artery occlusion/reperfusion. Ischemia/reperfusion and IKs blockade were found to significantly induce MAPD90 prolongation and increase triangulation at the epicardial zone at 45 min, 60 min, and 75 min after reperfusion, accompanied with an increase in premature ventricular beats (PVBs) during the same period. Additionally, IKs channel subunit expression was examined following transient ischemia or permanent infarction and changes in monophasic action potential (MAP) waveforms challenged by β-adrenergic stimulation were evaluated using a rabbit model of transient or chronic cardiac ischemia. The epicardial MAP in the peri-infarct zone of hearts subjected to infarction for 2 days exhibited increased triangulation under adrenergic stimulation. KCNQ1 protein, the α subunit of the IKs channel, was downregulated in the same group. Both findings were consistent with an increased incidence of PVBs. Conclusion Blockade of IKs caused MAP triangulation, which precipitated ventricular arrhythmias. Chronic ischemia increased the incidence of ventricular arrhythmias under adrenergic stimulation and was associated with increased MAP triangulation of the peri-infarct zone. Downregulation of KCNQ1 protein may be the underlying cause of these changes.
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Affiliation(s)
- Xiaogang Guo
- Department of Cardiology, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
| | - Xiuren Gao
- Department of Cardiology, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
- * E-mail: (X. Gao); (SW)
| | - Yesong Wang
- Department of Cardiology, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
| | - Longyun Peng
- Department of Cardiology, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
| | - Yingying Zhu
- Intensive Care Unit, Central Hospital, Tai'an, China
| | - Shenming Wang
- Department of Vascular Surgery, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
- * E-mail: (X. Gao); (SW)
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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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Drug-Induced QTC Prolongation Dangerously Underestimates Proarrhythmic Potential: Lessons From Terfenadine. J Cardiovasc Pharmacol 2011; 57:589-97. [DOI: 10.1097/fjc.0b013e3182135e91] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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A step towards characterisation of electrophysiological profile of torsadogenic drugs. J Pharmacol Toxicol Methods 2011; 63:269-78. [PMID: 21224008 DOI: 10.1016/j.vascn.2011.01.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2010] [Revised: 08/27/2010] [Accepted: 01/03/2011] [Indexed: 12/16/2022]
Abstract
INTRODUCTION In a previous study, two electrophysiological patterns for torsadogenic drugs were characterised in the model of isolated canine Purkinje fibres from their respective effects on action potential. This study was designed to elucidate the possible mechanisms underlying these two electrophysiological profiles. METHODS Effects of representative torsadogenic agents and non torsadogenic drugs on I(Kr), I(Ks), I(K1), I(Na) and I(CaL) were studied in transfected HEK 293 cells using the path-clamp method as well as in conscious beagle dogs and cynomolgus monkeys by telemetry. RESULTS Patch-clamp studies confirmed that torsadogenic molecules could be discriminated into at least two subgroups. The first subgroup can be defined as apparently pure I(Kr) blockers. The second subgroup can be defined as I(Kr) blockers with ancillary properties on sodium and/or calcium channels which counterbalance the I(Kr) prolongation component. This discrimination is transposable to the telemetered cynomolgus monkey model in terms of QT prolongation but not to the telemetered beagle dog model. This latter inter-species difference could be related to the sympathetic/parasympathetic balance and could involve reserve repolarisation dependent mechanisms. DISCUSSION The confirmation that torsadogenic drugs might have at least two different electrophysiological profiles should be taken into consideration in preclinical safety pharmacology studies because it increases the value of the cynomolgus monkey model in two particular situations: firstly when an NCE causes sympathetic activation and secondly, when an NCE exhibits a pure I(Kr) blocker pattern independently of its potency to block HERG channels.
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Thomas G, Klatt B, Blight A. Effect of 4-Aminopyridine on Action Potential Parameters in Isolated Dog Purkinje Fibers. ACTA ACUST UNITED AC 2010; 3:19-25. [PMID: 20428229 PMCID: PMC2855834 DOI: 10.1111/j.1753-5174.2009.00027.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Introduction 4-Aminopyridine (fampridine), a potassium channel blocker, has demonstrated efficacy in improving lower extremity strength and walking speed in patients with multiple sclerosis. Since in vitro electrophysiologic studies are recommended for evaluating a drug's potential to prolong the QT interval and induce such cardiac arrhythmias as Torsades de Pointes, we examined the electrophysiologic effects of 4-aminopyridine (0.5, 5.0, 50, and 500 µM) on isolated canine Purkinje fibers. Methods Microelectrodes monitored the resting membrane potential, overshoot, amplitude of action potential (AP), and maximal rate of depolarization of the AP upstroke in Purkinje fibers stimulated at 0.5 and 1.0 Hz. Results None of the above variables were altered in the presence of 4-aminopyridine. The AP duration at 30%, 50%, and 90% repolarization was also monitored, with only the 500-µM concentration at the 1.0-Hz frequency significantly increasing these values with respect to baseline (P < 0.05). However, the small sample size (N = 4) was small. The proportional increases, and their 95% confidence intervals, were 90.8% (−36.4%, 218.0%), 25.8% (11.9%, 39.7%), and 22.0% (14.9%, 29.1%) for APD 30%, 50%, and 90% repolarization, respectively. Reverse rate dependence was not observed, suggesting inhibition of ion channels other than those contributing to QT interval prolongation.
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Champeroux P, Ouillé A, Martel E, Fowler JSL, Maurin A, Jude S, Lala P, Le Guennec JY, Richard S. Interferences of the autonomic nervous system with drug induced QT prolongation: a point to consider in non-clinical safety studies. J Pharmacol Toxicol Methods 2010; 61:251-63. [PMID: 20172034 DOI: 10.1016/j.vascn.2010.02.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2009] [Revised: 02/08/2010] [Accepted: 02/10/2010] [Indexed: 02/03/2023]
Abstract
INTRODUCTION QT interval assessment by telemetry has become one of the most useful models in testing strategies adopted for detection of drug induced QT prolongation in non-clinical safety pharmacology studies. This study reports experimental data showing that the autonomic nervous system might influence drug induced QT prolongation. METHODS Animals were instrumented with telemetric transmitters and epicardial ECG leads. Effects on QT interval of reference drugs such as thioridazine and terfenadine were analysed with different approaches, the Holzgrefe's probabilistic method, the QT shift method and an individual analysis of beat-to-beat QT/RR pair distribution visualised as points-cloud. RESULTS Two cases of unexpected absence of QT interval prolongation are reported with thioridazine and terfenadine in conscious beagle dogs under conditions of concomitant tachycardia. The pro-arrhythmic properties of these two molecules were unmasked by co-treatment with sympatholytic agents, atenolol and clonidine respectively suggesting that sympathetic activation and/or parasympathetic withdrawal might impair a drug induced QT prolongation. DISCUSSION The apparent absence of changes in the QT interval due to novel drug candidates should be interpreted cautiously under conditions of concomitant tachycardia or elevated heart rate levels in non-clinical safety studies.
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Affiliation(s)
- Pascal Champeroux
- Centre de Recherches Biologiques, CERB, Chemin de Montifault, 18800 Baugy, France.
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Guo L, Dong Z, Guthrie H. Validation of a guinea pig Langendorff heart model for assessing potential cardiovascular liability of drug candidates. J Pharmacol Toxicol Methods 2009; 60:130-51. [DOI: 10.1016/j.vascn.2009.07.002] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2009] [Accepted: 07/06/2009] [Indexed: 02/02/2023]
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Abi-Gerges N, Valentin JP, Pollard CE. Dog left ventricular midmyocardial myocytes for assessment of drug-induced delayed repolarization: short-term variability and proarrhythmic potential. Br J Pharmacol 2009; 159:77-92. [PMID: 19663882 DOI: 10.1111/j.1476-5381.2009.00338.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
BACKGROUND AND PURPOSE Evaluation of the potential for delayed ventricular repolarization and proarrhythmia by new drugs is essential. We investigated if dog left ventricular midmyocardial myocytes (LVMMs) that can be used as a preclinical model to assess drug effects on action potential duration (APD) and whether in these cells, short-term variability (STV) or triangulation could predict proarrhythmic potential. EXPERIMENTAL APPROACH Beagle LVMMs and Purkinje fibres (PFs) were used to record APs. Effects of six reference drugs were assessed on APD at 50% (APD(50)) and 90% (APD(90)) of repolarization, STV(APD), triangulation (ratio APD(90)/APD(50)) and incidence of early afterdepolarizations (EADs) at 1 and 0.5 Hz. KEY RESULTS LVMMs provided stable recordings of AP, which were not affected by four sequential additions of dimethyl sulphoxide. Effects of dofetilide, d-sotalol, cisapride, pinacidil and diltiazem, but not of terfenadine, on APD in LVMMs were found to be comparable with those recorded in PFs. LVMMs, but not PFs, exhibited a proarrhythmic response to I(Kr) blockers. Incidence of EADs was not related to differences in AP prolongation or triangulation, but corresponded to beat-to-beat variability of repolarization, here quantified as STV of APD. CONCLUSIONS AND IMPLICATIONS LVMMs provide a suitable preclinical model to assess the effects of new drugs on APD and also yield additional information about putative indicators of proarrhythmia that add value to an integrated QT/TdP risk assessment. Our findings support the concept that increased STV(APD) may predict drug-induced proarrhythmia.
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Affiliation(s)
- Najah Abi-Gerges
- Safety Pharmacology Department, Safety Assessment UK, AstraZeneca R&D, Mereside, Alderley Park, Macclesfield, Cheshire, UK.
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Raghu K, Singh R, Prathapan A, Yadav GK. Modulation of haloperidol induced electrophysiological alterations on cardiac action potential by various risk factors and gender difference. Chem Biol Interact 2009; 180:454-9. [DOI: 10.1016/j.cbi.2009.05.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2008] [Revised: 05/01/2009] [Accepted: 05/01/2009] [Indexed: 11/30/2022]
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Hardy MEL, Pollard CE, Small BG, Bridgland-Taylor M, Woods AJ, Valentin JP, Abi-Gerges N. Validation of a voltage-sensitive dye (di-4-ANEPPS)-based method for assessing drug-induced delayed repolarisation in beagle dog left ventricular midmyocardial myocytes. J Pharmacol Toxicol Methods 2009; 60:94-106. [PMID: 19414070 DOI: 10.1016/j.vascn.2009.03.005] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2009] [Accepted: 03/10/2009] [Indexed: 10/20/2022]
Abstract
INTRODUCTION Evaluation of drug candidates in in-vitro assays of action potential duration (APD) is one component of preclinical safety assessment. Current assays are limited by technically-demanding, time-consuming electrophysiological methods. This study aimed to assess whether a voltage-sensitive dye-based assay could be used instead. METHODS Optical APs were recorded using di-4-ANEPPS in electrically field stimulated beagle left ventricular midmyocardial myocytes (LVMMs). Pharmacological properties of di-4-ANEPPS on the main cardiac ion channels that shape the ventricular AP were investigated using IonWorks and conventional electrophysiology. Effects of 9 reference drugs (dofetilide, E4031, D-sotalol, ATXII, cisapride, terfenadine, alfuzosin, diltiazem and pinacidil) with known APD-modulating effects were assessed on optically measured APD at 1 Hz. RESULTS Under optimum conditions, 0.1 microM di-4-ANEPPS could be used to monitor APs paced at 1 Hz during nine, 5 s exposures without altering APD. di-4-ANEPPS had no effect on either hI(ERG), hI(Na), hI(Ks) and hI(to) currents in transfected CHO cells (up to 10 microM) or I(Ca,L) current in LVMMs (at 16 microM). di-4-ANEPPS had no effect on APs recorded with microelectrodes at 1 or 0.5 Hz over a period of 30 min di-4-ANEPPS displayed the sensitivity to record changes in optically measured APD in response to altered pacing frequencies and sequential vehicle additions did not affect the optically measured APD. APD data obtained with 9 reference drugs were as expected except (i) D-sotalol-induced increases in duration were smaller than those caused by other I(Kr) blockers and (ii) increases in APD were not detected using low concentrations of terfenadine. DISCUSSION Early in drug discovery, the di-4-ANEPPS-based method can reliably be used to assess drug effects on APD as part of a cardiac risk assessment strategy.
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Affiliation(s)
- Matthew E L Hardy
- Safety Pharmacology Department, Safety Assessment UK, AstraZeneca R&D, Alderley Park, Macclesfield, Cheshire SK104TG, UK
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Calculation of QT shift in non clinical safety pharmacology studies. J Pharmacol Toxicol Methods 2008; 59:73-85. [PMID: 19135537 DOI: 10.1016/j.vascn.2008.11.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2008] [Accepted: 11/18/2008] [Indexed: 11/23/2022]
Abstract
INTRODUCTION Drug-induced QT interval prolongation is a major concern in new drug candidate development. This study presents a method of assessment of drug-induced QT interval prolongation without need for QT correction in conscious Beagle dogs and Cynomolgus monkeys monitored by telemetry. Accuracy and reliability are analysed by comparison with a reference QT correction method (Holzgrefe) from experiments performed with reference substances terfenadine, thioridazine and sotalol. METHODS The QT shift method principle is assessment of any drug-induced QT interval shift directly from the individual QT/RR relationship. The individual QT/RR relationship is built from a treatment-free 24-hour recording period. QT and RR intervals are determined from a beat-to-beat analysis. A probabilistic method is used to define the individual QT/RR relationships. Checks were performed to compare results obtained with the QT shift method and the QT correction methods. The robustness of the QT shift method was tested under various conditions of drug-induced heart rate change (i.e. normal, bradycardia and tachycardia). RESULTS The extent of agreement with the used reference QT correction method, Holzgrefe formula, was excellent (3-4 ms) in both animal species under the various drug induced effects on heart rate. The statistical sensitivity threshold for detection of QT prolongation according to a standard safety pharmacology study design was 7-8 ms. DISCUSSION When combined with the probabilistic determination of individual QT/RR relationships, this simple method provides a direct assessment of a drug-induced effect on QT interval, without any curve fitting or application of correction formula. Despite noticeably different shapes in QT/RR relationships, the QT shift method is applicable to both Beagle dogs and Cynomolgus monkeys. It is likely that the QT shift method will be particularly helpful in problematic cases, enabling detection of drug-induced prolongation of less than 10 ms.
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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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Hondeghem LM. Use and abuse of QT and TRIaD in cardiac safety research: Importance of study design and conduct. Eur J Pharmacol 2008; 584:1-9. [DOI: 10.1016/j.ejphar.2008.01.016] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2007] [Revised: 12/19/2007] [Accepted: 01/15/2008] [Indexed: 10/22/2022]
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Lu HR, Vlaminckx E, Van de Water A, Rohrbacher J, Hermans A, Gallacher DJ. In-vitro experimental models for the risk assessment of antibiotic-induced QT prolongation. Eur J Pharmacol 2008; 577:222-32. [PMID: 18074444 DOI: 10.1016/j.ejphar.2007.07.070] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
The prolongation of the ventricular repolarization and proarrhythmic effects (Torsade de Pointes: TdP) of five reference antibiotics were compared in four in-vitro models. 1. Using the patch clamp technique on the human ether-a-gogo-related gene (HERG) current, the rank order for blockade of the HERG-current (IC(50)) was: sparfloxacin (44 microM)>telithromycin=moxifloxacin=erythromycin (+/-100 microM). 2. Assessing their effects on action potential duration (APD(90)) and incidence of early afterdepolarizations in isolated rabbit Purkinje fibers, the rank order was: sparfloxacin>moxifloxacin>telithromycin>erythromycin (prolongation of APD(90) at 100 microM: 83%, 48%, 33% and 17% from baseline compared to +5% with solvent, P<0.05, respectively). 3. Assessing the drug effects on the APD(60), triangulation, reverse use-dependency, and instability in isolated Langendorff-perfused rabbit hearts, the rank order was: moxifloxacin>erythromycin>sparfloxacin>telithromycin. 4. Assessing their torsadogenic potentials (scores of effects on QT-interval, peak of the T wave to end of T wave: T(p-e), T(p-e)/QT ratio, R wave on T wave (R on T) and TdP in isolated rabbit left ventricular wedge preparations, the rank order for their TdP risk score was: sparfloxacin>erythromycin>moxifloxacin>telithromycin. Additional experiments with grepafloxacin indicate that the rank order to detect grepafloxacin-induced long QT was the wedge preparation>the Purkinje fiber>HERG>the isolated heart, where the isolated heart was unable to detect grepafloxacin-induced APD prolongation. The present study demonstrates that the first three in-vitro models can be used to assess the ability of antibiotic compounds to delay ventricular repolarization. However, with respect to their known clinical effects on QT and TdP incidence, the wedge preparation appears to be more predictive and suitable for detecting torsadogenic action of antibiotics.
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Affiliation(s)
- Hua Rong Lu
- Center of Excellence for Cardiovascular Safety Research, Johnson & Johnson Pharmaceutical Research and Development, Division of Janssen Pharmaceutica N.V. B-2340, Beerse, Belgium.
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Steidl-Nichols JV, Hanton G, Leaney J, Liu RC, Leishman D, McHarg A, Wallis R. Impact of study design on proarrhythmia prediction in the SCREENIT rabbit isolated heart model. J Pharmacol Toxicol Methods 2008; 57:9-22. [PMID: 17707659 DOI: 10.1016/j.vascn.2007.06.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2006] [Accepted: 06/22/2007] [Indexed: 10/23/2022]
Abstract
INTRODUCTION Prediction of the propensity of a compound to induce Torsades de Pointes continues to be a formidable challenge to the pharmaceutical industry. Development of an in vitro model for assessment of proarrhythmic potential offers the advantage of higher throughput and reduced compound quantity requirements when compared to in vivo studies. A rabbit isolated heart model (SCREENIT) has been reported to identify compounds with proarrhythmic potential based on the observance of compound-induced triangulation and instability of the monophasic action potential (MAP), ectopic beats, and reverse-use dependence of prolongation of the MAP duration. Previous reports have indicated that this model qualitatively identifies proarrhythmic compounds and suggest the use of this model to assign safety margins for human clinical use. The intent of this series of studies was to evaluate the impact of study design on the proarrhythmic concentration predicted by this model. METHODS Nine compounds of varying proarrhythmic potential and a negative control were tested in a blinded fashion using a series of different experimental protocols: Compounds were tested at multiple concentration ranges and extended perfusion times were also evaluated. RESULTS In general when the dataset is viewed as a whole, the model did identify proarrhythmic compounds, however the concentration at which action potential prolongation, triangulation, instability, reverse-use dependence and ectopic beats occurred often varied based on the concentration range selected. Further analysis using extended compound perfusion times demonstrated that variability may be due in part to lack of adequate equilibration of compound with the cardiac tissue. DISCUSSION We report that the model correctly identified proarrhythmic agents in a qualitative manner, but that study design impacts the proarrhythmic concentration derived from the model.
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Affiliation(s)
- Jill V Steidl-Nichols
- Global Safety Pharmacology, Pfizer Global Research and Development, La Jolla Laboratories, 10646 Science Center Drive, San Diego, CA 92121, USA.
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Christ T, Wettwer E, Wuest M, Braeter M, Donath F, Champeroux P, Richard S, Ravens U. Electrophysiological profile of propiverine--relationship to cardiac risk. Naunyn Schmiedebergs Arch Pharmacol 2007; 376:431-40. [PMID: 18092154 DOI: 10.1007/s00210-007-0231-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2007] [Accepted: 11/22/2007] [Indexed: 10/22/2022]
Abstract
Drugs that prolong the QT interval by blocking human ether-a-go-go (HERG) channels may enhance the risk of ventricular arrhythmia. The spasmolytic drug propiverine is widely used for the therapy of overactive bladder (OAB). Here, we have investigated the effects of propiverine on cardiac ion channels and action potentials as well as on contractile properties of cardiac tissue, in order to estimate its cardiac safety profile, because other drugs used in this indication had to be withdrawn due to safety reasons. Whole-cell patch clamp technique was used to record the following cardiac ion currents: rapidly and slowly activating delayed rectifier K+ current (I(Kr), I(Ks)), ultra rapidly activating delayed rectifier K+ current (I(Kur)), inwardly rectifying K+ current I(K1), transient outward K+ current (I(to)), and L-type Ca2+ current (I(Ca,L)). Action potentials in cardiac tissue biopsies were recorded with conventional microelectrodes. The torsade de pointes screening assay (TDPScreen) was used for drug scoring. Propiverine blocked in a concentration-dependent manner HERG channels expressed in HEK293 cells, as well as native I(Kr) current in ventricular myocytes of guinea pig (IC50 values: 10 microM and 1.8 microM respectively). At high concentrations (100 microM), propiverine suppressed I(Ks). I(K1) and the transient outward current I(to) and I(Kur) were not affected. In guinea-pig ventricular and human atrial myocytes, propiverine also blocked I(Ca,L) (IC50 values: 34.7 microM and 41.7 microM, respectively) and reduced force of contraction. Despite block of I(Kr), action potential duration was not prolonged in guinea-pig and human ventricular tissue, but decreased progressively until excitation failed altogether. Similar effects were observed in dog Purkinje fibers. Propiverine obtained a low score in the TDPScreen. In conclusion, in vitro and in vivo studies of propiverine do not provide evidence for an enhanced cardiovascular safety risk. We propose that lack of torsadogenic risk of propiverine is related to enhancement of repolarization reserve by block of I(Ca,L).
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Affiliation(s)
- Torsten Christ
- Department of Pharmacology and Toxicology, Medical Faculty, Dresden University of Technology, Fetscherstrasse 74, 01307 Dresden, Germany
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Guo D, Zhou J, Zhao X, Gupta P, Kowey PR, Martin J, Wu Y, Liu T, Yan GX. L-type calcium current recovery versus ventricular repolarization: preserved membrane-stabilizing mechanism for different QT intervals across species. Heart Rhythm 2007; 5:271-9. [PMID: 18242553 DOI: 10.1016/j.hrthm.2007.09.025] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2007] [Accepted: 09/22/2007] [Indexed: 11/27/2022]
Abstract
BACKGROUND Long QT syndrome is associated with early after-depolarization (EAD) that may result in torsade de pointes (TdP). Interestingly, the corrected QT interval seems to be proportional to body mass across species under physiologic conditions. OBJECTIVE The purpose of this study was to test whether recovery of L-type calcium current (I(Ca,L)), the primary charge carrier for EADs, from its inactivated state matches ventricular repolarization time and whether impairment of this relationship leads to development of EAD and TdP. METHODS Transmembrane action potentials from the epicardium, endocardium, or subendocardium were recorded simultaneously with a transmural ECG in arterially perfused left ventricular wedges isolated from cow, dog, rabbit, and guinea pig hearts. I(Ca,L) recovery was examined using action potential stimulation in isolated left ventricular myocytes. RESULTS The ventricular repolarization time (action potential duration at 90% repolarization [APD(90)]), ranging from 194.7 +/- 1.8 ms in guinea pig to 370.2 +/- 9.9 ms in cows, was linearly related to the thickness of the left ventricular wall among the species studied. The time constants (tau) of I(Ca,L) recovery were proportional to APD(90), making the ratios of tau to APD(90) fall into a relatively narrow range among these species despite markedly different ventricular repolarization time. Drugs with risk for TdP in humans were shown to impair this intrinsic balance by either prolongation of the repolarization time and/or acceleration of I(Ca,L) recovery, leading to the appearance of EADs capable of initiating TdP. CONCLUSION An adequate balance between I(Ca,L) recovery and ventricular repolarization serves as a "physiologic stabilizer" of ventricular action potentials in repolarization phases.
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Affiliation(s)
- Donglin Guo
- Main Line Health Heart Center, Wynnewood, Pennsylvania 19096, USA
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Bourrinet P, Martel E, El Amrani AI, Champeroux P, Richard S, Fauchou N, Le Coz F, Drici M, Bonnemain B, Gaillard S. Cardiovascular Safety of Gadoterate Meglumine (Gd-DOTA). Invest Radiol 2007; 42:63-77. [PMID: 17220724 DOI: 10.1097/01.rli.0000251565.61487.1a] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVES Gadolinium complexes are not considered to be a drug class at high risk for prolonging cardiac repolarization, which can lead to potentially life-threatening arrhythmias such as torsade de pointes. However, only limited robust data are available on these compounds despite their extensive use as contrast enhancers in magnetic resonance imaging. We present an overview of recent cardiovascular safety data obtained on gadoterate meglumine (Gd-DOTA). MATERIALS AND METHODS Cardiovascular safety was evaluated by "state-of-the-art" nonclinical ex vitro (dog Purkinje fibers) and in vivo studies in both normal (dogs) and sensitized animal models (rabbits) and in patients with various diseases in a specific clinical trial. RESULTS In all of these studies, Gd-DOTA did not show any direct deleterious effect on cardiac electrophysiology and especially on ventricular repolarization. CONCLUSION These results confirmed the good safety profile of Gd-DOTA derived from postmarketing evaluations. Nonspecific gadolinium complexes used for magnetic resonance contrast enhancement do not constitute a class-at-risk for drug-related arrhythmias.
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Guo D, Zhao X, Wu Y, Liu T, Kowey PR, Yan GX. L-type calcium current reactivation contributes to arrhythmogenesis associated with action potential triangulation. J Cardiovasc Electrophysiol 2006; 18:196-203. [PMID: 17212595 DOI: 10.1111/j.1540-8167.2006.00698.x] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
INTRODUCTION The morphology of the mammalian cardiac action potential (AP) is an important factor in the susceptibility to drug-induced early afterdepolarizations (EADs) that may initiate torsade de pointes (TdP). AP triangulation has been shown to be an important predictor of drug-induced TdP. METHODS AND RESULTS APs from guinea pig and rabbit left ventricular single myocytes were recorded using a microelectrode-recording technique. I(Ca-L) currents were recorded in ventricular myocytes of guinea pig and rabbit using patch-clamping technique. At a stimulus frequency of 0.5 Hz, guinea pig ventricular myocytes displayed a square-like AP, whereas rabbit ventricular myocytes exhibited a triangle-like AP. Dofetilide-induced EADs were observed only in rabbit ventricular myocytes. Under the guinea pig AP clamping condition, the normalized I(Ca-L) instant reactivation currents in guinea pig and rabbit myocytes at voltages of -40 mV were 0.13 +/- 0.01 and 0.14 +/- 0.01, respectively. However, when rabbit AP served as the first clamping voltage, the normalized I(Ca-L) reactivation currents at -40 mV in guinea pig and rabbit myocytes were 0.20 +/- 0.01, 0.21 +/- 0.01, respectively, indicating that the I(Ca-L) recovery from inactivation in the rabbit triangular AP condition was significantly faster than in the guinea pig square AP condition. Comparison of the voltage clamp using the triangular waveform with the square waveform further confirmed that triangulation accelerates I(Ca-L) recovery from inactivation. CONCLUSIONS In rabbit ventricular myocardium, AP triangulation accelerates I(Ca-L) channel recovery from inactivation, leading to instability of the cell membrane potential during repolarization, which is capable of initiating TdP.
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Affiliation(s)
- Donglin Guo
- Main Line Health Heart Center, Wynnewood, Pennsylvania 19096, USA.
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Lawrence CL, Bridgland-Taylor MH, Pollard CE, Hammond TG, Valentin JP. A rabbit Langendorff heart proarrhythmia model: predictive value for clinical identification of Torsades de Pointes. Br J Pharmacol 2006; 149:845-60. [PMID: 17031389 PMCID: PMC2014697 DOI: 10.1038/sj.bjp.0706894] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2006] [Revised: 06/19/2006] [Accepted: 08/11/2006] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND AND PURPOSE The rabbit isolated Langendorff heart model (SCREENIT) was used to investigate the proarrhythmic potential of a range of marketed drugs or drugs intended for market. These data were used to validate the SCREENIT model against clinical outcomes. EXPERIMENTAL APPROACH Fifty-five drugs, 3 replicates and 2 controls were tested in a blinded manner. Proarrhythmia variables included a 10% change in MAPD(60), triangulation, instability and reverse frequency-dependence of the MAP. Early after-depolarisations, ventricular tachycardia, TdP and ventricular fibrillation were noted. Data are reported at nominal concentrations relative to EFTPC(max). Proarrhythmic scores were assigned to each drug and each drug category. KEY RESULTS Category 1 and 2 drugs have the highest number of proarrhythmia variables and overt proarrhythmia while Category 5 drugs have the lowest, at every margin. At 30-fold the EFTPC(max), the mean proarrhythmic scores are: Category 1, 101+/-24; Category 2, 101+/-14; Category 3, 72+/-20; Category 4, 59+/-16 and Category 5, 22+/-9 points. Only drugs in Category 5 have mean proarrhythmic scores, below 30-fold, that remain within the Safety Zone. CONCLUSIONS AND IMPLICATIONS A 30-fold margin between effects and EFTPC(max) is sufficiently stringent to provide confidence to proceed with a new chemical entity, without incurring the risk of eliminating potentially beneficial drugs. The model is particularly useful where compounds have small margins between the hERG IC(50) and predicted EFTPC(max). These data suggest this is a robust and reliable assay that can add value to an integrated QT/TdP risk assessment.
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Affiliation(s)
- C L Lawrence
- Safety Pharmacology, Safety Assessment UK, AstraZeneca R&D, Macclesfield, Cheshire, UK.
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Lu HR, Vlaminckx E, Van de Water A, Rohrbacher J, Hermans A, Gallacher DJ. In-vitro experimental models for the risk assessment of antibiotic-induced QT prolongation. Eur J Pharmacol 2006; 553:229-39. [PMID: 17054943 DOI: 10.1016/j.ejphar.2006.09.035] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2006] [Revised: 09/06/2006] [Accepted: 09/12/2006] [Indexed: 11/27/2022]
Abstract
The prolongation of the ventricular repolarization and proarrhythmic effects (Torsade de Pointes: TdP) of five reference antibiotics were compared in four in-vitro models. 1. Using the patch clamp technique on the human ether-a-gogo-related gene (HERG) current, the rank order for blockade of the HERG-current (IC(50)) was: sparfloxacin (44 microM)>telithromycin=moxifloxacin=erythromycin (+/-100 microM). 2. Assessing their effects on action potential duration (APD(90)) and incidence of early afterdepolarizations in isolated rabbit Purkinje fibers, the rank order was: sparfloxacin>moxifloxacin>telithromycin>erythromycin (prolongation of APD(90) at 100 microM: 83%, 48%, 33% and 17% from baseline compared to +5% with solvent, P<0.05, respectively). 3. Assessing the drug effects on the APD(60), triangulation, reverse use-dependency, and instability in isolated Langendorff-perfused rabbit hearts, the rank order was: moxifloxacin>erythromycin>sparfloxacin>telithromycin. 4. Assessing their torsadogenic potentials (scores of effects on QT-interval, peak of the T wave to end of T wave: T(p-e), T(p-e)/QT ratio, R wave on T wave (R on T) and TdP in isolated rabbit left ventricular wedge preparations, the rank order for their TdP risk score was: sparfloxacin>erythromycin>moxifloxacin>telithromycin. Additional experiments with grepafloxacin indicate that the rank order to detect grepafloxacin-induced long QT was the wedge preparation>the Purkinje fiber>HERG>the isolated heart, where the isolated heart was unable to detect grepafloxacin-induced APD prolongation. The present study demonstrates that the first three in-vitro models can be used to assess the ability of antibiotic compounds to delay ventricular repolarization. However, with respect to their known clinical effects on QT and TdP incidence, the wedge preparation appears to be more predictive and suitable for detecting torsadogenic action of antibiotics.
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Affiliation(s)
- Hua Rong Lu
- Center of Excellence for Cardiovascular Safety Research, Johnson and Johnson Pharmaceutical Research and Development, a Division of Janssen Pharmaceutica N.V. B-2340, Beerse, Belgium.
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Martin RL, Su Z, Limberis JT, Palmatier JD, Cowart MD, Cox BF, Gintant GA. In Vitro Preclinical Cardiac Assessment of Tolterodine and Terodiline: Multiple Factors Predict the Clinical Experience. J Cardiovasc Pharmacol 2006; 48:199-206. [PMID: 17110801 DOI: 10.1097/01.fjc.0000246853.15926.d4] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Terodiline and tolterodine are drugs used to treat urinary incontinence. Terodiline was removed from the market in 1991 for proarrhythmia, whereas tolterodine has a generally benign clinical cardiac profile. To assess differences in the electrophysiologic actions of these drugs, we evaluated their effects on hERG current (HEK cells) and cardiac Purkinje fiber repolarization. The IC50 for hERG block (37 degrees C) by tolterodine was 9.6 nM and by terodiline was 375 nM, values near or below clinical concentrations. Tolterodine elicited concentration-dependent prolongation of the action potential duration (APD90). In contrast, terodiline depressed the action potential plateau and induced triangulation without affecting APD90. The triangulation ratios (normalized ratio of APD50 over APD90) for terodiline were 0.94 and 0.59 for 1.0 and 10 microM and for tolterodine, were 0.99 and 0.97 at 7 and 70 nM. In summary, tolterodine, a potent hERG blocker, has a benign clinical cardiac profile at therapeutic concentrations that may be due to its lack of triangulation, as well as extensive plasma protein binding. However, at supratherapeutic concentrations, preclinical data predict risk of QT prolongation. These data suggest that hERG block and triangulation are among multiple factors that must be considered in preclinical cardiac safety assessments.
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Affiliation(s)
- Ruth L Martin
- Department of Integrative Pharmacology, Abbott, Abbott Park, Illinois 60064-6119, USA.
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Liu T, Brown BS, Wu Y, Antzelevitch C, Kowey PR, Yan GX. Blinded validation of the isolated arterially perfused rabbit ventricular wedge in preclinical assessment of drug-induced proarrhythmias. Heart Rhythm 2006; 3:948-56. [PMID: 16876745 PMCID: PMC1955432 DOI: 10.1016/j.hrthm.2006.04.021] [Citation(s) in RCA: 97] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/07/2006] [Accepted: 04/16/2006] [Indexed: 11/20/2022]
Abstract
BACKGROUND The development of preclinical models with high predictive value for the identification of drugs with a proclivity to induce Torsade de Pointes (TdP) in the clinic has long been a pressing goal of academia, industry and regulatory agencies alike. The present study provides a blinded appraisal of drugs, in an isolated arterially-perfused rabbit ventricular wedge preparation, with and without the potential to produce TdP. METHODS AND RESULTS Thirteen compounds were tested for their potential for TdP using the rabbit left ventricular wedges. All investigators were blinded to the names, concentrations and molecular weights of the drugs. The compounds were prepared by the study sponsor and sent to the investigator as 4 sets of 13 stock solutions with the order within each set being assigned by a random number generator. Each compound was scored semi-quantitatively for its relative potential for TdP based on its effect on ventricular repolarization measured as QT interval, dispersion of repolarization measured as T(p-e)/QT ratio and early afterdepolarizations. Disclosure of the names and concentrations after completion of the study revealed that all compounds known to be free of TdP risk received a score of less or equal to 0.25, whereas those with known TdP risk received a score ranging from 1.00 to 7.25 at concentrations less than 100X their free therapeutic plasma C(max). CONCLUSIONS Our study provides a blinded evaluation of the isolated arterially-perfused rabbit wedge preparation demonstrating both a high sensitivity and specificity in the assessment of 13 agents with varying propensity for causing TdP.
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Affiliation(s)
| | | | - Ying Wu
- Main Line Health Heart Center, Wynnewood, PA
| | | | - Peter R Kowey
- Main Line Health Heart Center, Wynnewood, PA
- Jefferson Medical College of Thomas Jefferson University, Philadelphia, PA, 19107
| | - Gan-Xin Yan
- Main Line Health Heart Center, Wynnewood, PA
- Jefferson Medical College of Thomas Jefferson University, Philadelphia, PA, 19107
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Cavero I, Crumb W. ICH S7B draft guideline on the non-clinical strategy for testing delayed cardiac repolarisation risk of drugs: a critical analysis. Expert Opin Drug Saf 2005; 4:509-30. [PMID: 15934857 DOI: 10.1517/14740338.4.3.509] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The International Conference on Harmonization (ICH) stems from the initiative of three major world partners (Japan, USA, European Community) who composed a mutually accepted body of regulations concerning the safety, quality and efficacy requirements that new medicines have to meet in order to receive market approval. Documents on non-clinical safety pharmacology already composed by this organisation include two guidelines: the S7A adopted in 2000 and, its companion, the S7B guideline, in a draft form since 2001. The S7A guideline deals with general principles and recommendations on safety pharmacology studies designed to protect healthy volunteers and patients from potential drug-induced adverse reactions. The S7B recommends a general non-clinical testing strategy for determining the propensity of non-cardiovascular pharmaceuticals to delay ventricular repolarisation, an effect that at times progresses into life-threatening ventricular arrhythmia. In the most recent version of this document (June 2004), the strategy proposes experimental assays and a critical examination of other pertinent information for applying an 'evidence of risk' label to a compound. Regrettably, the guideline fails to deal satisfactorily with a number of crucial issues such as scoring the evidence of risk and the clinical consequences of such scoring. However, in the latter case, the S7B relies on the new ICH guideline E14 which is currently in preparation. E14 is the clinical counterpart of the S7B guideline which states that non-clinical data are a poor predictor of drug-induced repolarisation delay in humans. The present contribution summarises and assesses salient aspects of the S7A guideline as its founding principles are also applicable to the S7B guideline. The differences in strategies proposed by the various existing drafts of the latter document are critically examined together with some unresolved, crucial problems. The need for extending the objective of the S7B document to characterise the full electrophysiological profile of new pharmaceuticals is argued as this approach would more extensively assess the non-clinical cardiac safety of a drug. Finally, in order to overcome present difficulties in arriving at the definitive version of the S7B guideline, the Expert Working Group could reflect on the introduction of the S7B guideline recommendations in the S7A document, as originally intended, or on postponing the adoption of an harmonized text until the availability of novel scientific data allows solving presently contentious aspects of this and the E14 guidelines.
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