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Ellermann C, Wolfes J, Eckardt L, Frommeyer G. Role of the rabbit whole-heart model for electrophysiologic safety pharmacology of non-cardiovascular drugs. Europace 2021; 23:828-836. [PMID: 33200170 DOI: 10.1093/europace/euaa288] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Accepted: 08/27/2020] [Indexed: 11/13/2022] Open
Abstract
Plenty of non-cardiovascular drugs alter cardiac electrophysiology and may ultimately lead to life-threatening arrhythmias. In clinical practice, measuring the QT interval as a marker for the repolarization period is the most common tool to assess the electrophysiologic safety of drugs. However, the sole measurement of the QT interval may be insufficient to determine the proarrhythmic risk of non-cardiovascular agents. Several other markers are considered in pre-clinical safety testing to determine potential harm on cardiac electrophysiology. Besides measuring typical electrophysiologic parameters such as repolarization duration, whole-heart models allow the determination of potential predictors for proarrhythmia. Spatial and temporal heterogeneity as well as changes of shape of the action potential can be easily assessed. In addition, provocation manoeuvers (either by electrolyte imbalances or programmed pacing protocols) may induce sustained arrhythmias and thereby determine ventricular vulnerability to arrhythmias. Compared with the human heart, the rabbit heart possesses a similar distribution of ion currents that govern cardiac repolarization, resulting in a rectangular action potential configuration in both species. In addition, similar biophysical properties of rabbit and human cardiac ion channels lead to a comparable pharmacologic response in human and rabbit hearts. Of note, arrhythmia patterns resemble in both species due to the similar effective size of human and rabbit hearts. Thus, the rabbit heart is particularly suitable for testing the electrophysiologic safety of drugs. Several experimental setups have been developed for studying cardiac electrophysiology in rabbits, ranging from single cell to tissue preparations, whole-heart setups, and in vivo models.
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Affiliation(s)
- Christian Ellermann
- Department of Cardiology II (Electrophysiology), University Hospital Münster, Albert-Schweitzer-Campus 1, Münster D-48149, Germany
| | - Julian Wolfes
- Department of Cardiology II (Electrophysiology), University Hospital Münster, Albert-Schweitzer-Campus 1, Münster D-48149, Germany
| | - Lars Eckardt
- Department of Cardiology II (Electrophysiology), University Hospital Münster, Albert-Schweitzer-Campus 1, Münster D-48149, Germany
| | - Gerrit Frommeyer
- Department of Cardiology II (Electrophysiology), University Hospital Münster, Albert-Schweitzer-Campus 1, Münster D-48149, Germany
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Hornyik T, Castiglione A, Franke G, Perez-Feliz S, Major P, Hiripi L, Koren G, Bősze Z, Varró A, Zehender M, Brunner M, Bode C, Baczkó I, Odening KE. Transgenic LQT2, LQT5, and LQT2-5 rabbit models with decreased repolarisation reserve for prediction of drug-induced ventricular arrhythmias. Br J Pharmacol 2020; 177:3744-3759. [PMID: 32436214 PMCID: PMC7393202 DOI: 10.1111/bph.15098] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 04/09/2020] [Accepted: 04/23/2020] [Indexed: 12/21/2022] Open
Abstract
Background and Purpose Reliable prediction of pro‐arrhythmic side effects of novel drug candidates is still a major challenge. Although drug‐induced pro‐arrhythmia occurs primarily in patients with pre‐existing repolarisation disturbances, healthy animals are employed for pro‐arrhythmia testing. To improve current safety screening, transgenic long QT (LQTS) rabbit models with impaired repolarisation reserve were generated by overexpressing loss‐of‐function mutations of human HERG (HERG‐G628S, loss of IKr; LQT2), KCNE1 (KCNE1‐G52R, decreased IKs; LQT5), or both transgenes (LQT2‐5) in the heart. Experimental Approach Effects of K+ channel blockers on cardiac repolarisation and arrhythmia susceptibility were assessed in healthy wild‐type (WT) and LQTS rabbits using in vivo ECG and ex vivo monophasic action potential and ECG recordings in Langendorff‐perfused hearts. Key Results LQTS models reflect patients with clinically “silent” (LQT5) or “manifest” (LQT2 and LQT2‐5) impairment in cardiac repolarisation reserve: they were more sensitive in detecting IKr‐blocking (LQT5) or IK1/IKs‐blocking (LQT2 and LQT2‐5) properties of drugs compared to healthy WT animals. Impaired QT‐shortening capacity at fast heart rates was observed due to disturbed IKs function in LQT5 and LQT2‐5. Importantly, LQTS models exhibited higher incidence, longer duration, and more malignant types of ex vivo arrhythmias than WT. Conclusion and Implications LQTS models represent patients with reduced repolarisation reserve due to different pathomechanisms. As they demonstrate increased sensitivity to different specific ion channel blockers (IKr blockade in LQT5 and IK1 and IKs blockade in LQT2 and LQT2‐5), their combined use could provide more reliable and more thorough prediction of (multichannel‐based) pro‐arrhythmic potential of novel drug candidates.
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Affiliation(s)
- Tibor Hornyik
- Department of Cardiology and Angiology I, Heart Center University of Freiburg, Medical Faculty, Freiburg, Germany.,Institute of Experimental Cardiovascular Medicine, Heart Center University of Freiburg, Medical Faculty, Freiburg, Germany.,Department of Pharmacology and Pharmacotherapy, University of Szeged, Szeged, Hungary
| | - Alessandro Castiglione
- Department of Cardiology and Angiology I, Heart Center University of Freiburg, Medical Faculty, Freiburg, Germany
| | - Gerlind Franke
- Department of Cardiology and Angiology I, Heart Center University of Freiburg, Medical Faculty, Freiburg, Germany
| | - Stefanie Perez-Feliz
- Department of Cardiology and Angiology I, Heart Center University of Freiburg, Medical Faculty, Freiburg, Germany.,Institute of Experimental Cardiovascular Medicine, Heart Center University of Freiburg, Medical Faculty, Freiburg, Germany
| | - Péter Major
- NARIC-Agricultural Biotechnology Institute, Animal Biotechnology Department, Gödöllő, Hungary
| | - László Hiripi
- NARIC-Agricultural Biotechnology Institute, Animal Biotechnology Department, Gödöllő, Hungary
| | - Gideon Koren
- Cardiovascular Research Center, Brown University, Providence, Rhode Island, USA
| | - Zsuzsanna Bősze
- NARIC-Agricultural Biotechnology Institute, Animal Biotechnology Department, Gödöllő, Hungary
| | - András Varró
- Department of Pharmacology and Pharmacotherapy, University of Szeged, Szeged, Hungary
| | - Manfred Zehender
- Department of Cardiology and Angiology I, Heart Center University of Freiburg, Medical Faculty, Freiburg, Germany
| | - Michael Brunner
- Department of Cardiology and Angiology I, Heart Center University of Freiburg, Medical Faculty, Freiburg, Germany.,Department of Cardiology and Medical Intensive Care, St. Josefskrankenhaus, Freiburg, Germany
| | - Christoph Bode
- Department of Cardiology and Angiology I, Heart Center University of Freiburg, Medical Faculty, Freiburg, Germany
| | - István Baczkó
- Department of Pharmacology and Pharmacotherapy, University of Szeged, Szeged, Hungary
| | - Katja E Odening
- Department of Cardiology and Angiology I, Heart Center University of Freiburg, Medical Faculty, Freiburg, Germany.,Institute of Experimental Cardiovascular Medicine, Heart Center University of Freiburg, Medical Faculty, Freiburg, Germany.,Translational Cardiology, Department of Cardiology, Inselspital, Bern University Hospital, and Institute of Physiology, University of Bern, Bern, Switzerland
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