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Lyon A, Dupuis LJ, Arts T, Crijns HJGM, Prinzen FW, Delhaas T, Heijman J, Lumens J. Differentiating the effects of β-adrenergic stimulation and stretch on calcium and force dynamics using a novel electromechanical cardiomyocyte model. Am J Physiol Heart Circ Physiol 2020; 319:H519-H530. [PMID: 32734816 DOI: 10.1152/ajpheart.00275.2020] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Cardiac electrophysiology and mechanics are strongly interconnected. Calcium is crucial in this complex interplay through its role in cellular electrophysiology and sarcomere contraction. We aim to differentiate the effects of acute β-adrenergic stimulation (β-ARS) and cardiomyocyte stretch (increased sarcomere length) on calcium-transient dynamics and force generation, using a novel computational model of cardiac electromechanics. We implemented a bidirectional coupling between the O'Hara-Rudy model of human ventricular electrophysiology and the MechChem model of sarcomere mechanics through the buffering of calcium by troponin. The coupled model was validated using experimental data from large mammals or human samples. Calcium transient and force were simulated for various degrees of β-ARS and initial sarcomere lengths. The model reproduced force-frequency, quick-release, and isotonic contraction experiments, validating the bidirectional electromechanical interactions. An increase in β-ARS increased the amplitudes of force (augmented inotropy) and calcium transient, and shortened both force and calcium-transient duration (lusitropy). An increase in sarcomere length increased force amplitude even more, but decreased calcium-transient amplitude and increased both force and calcium-transient duration. Finally, a gradient in relaxation along the thin filament may explain the nonmonotonic decay in cytosolic calcium observed with high tension. Using a novel coupled human electromechanical model, we identified differential effects of β-ARS and stretch on calcium and force. Stretch mostly contributed to increased force amplitude and β-ARS to the reduction of calcium and force duration. We showed that their combination, rather than individual contributions, is key to ensure force generation, rapid relaxation, and low diastolic calcium levels.NEW & NOTEWORTHY This work identifies the contribution of electrical and mechanical alterations to regulation of calcium and force under exercise-like conditions using a novel human electromechanical model integrating ventricular electrophysiology and sarcomere mechanics. By better understanding their individual and combined effects, this can uncover arrhythmogenic mechanisms in exercise-like situations. This publicly available model is a crucial step toward understanding the complex interplay between cardiac electrophysiology and mechanics to improve arrhythmia risk prediction and treatment.
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Affiliation(s)
- Aurore Lyon
- Department of Biomedical Engineering, Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, The Netherlands
| | - Lauren J Dupuis
- Department of Biomedical Engineering, Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, The Netherlands.,Department of Bioinformatics-BiGCaT, School of Nutrition and Translational Research in Metabolism, Maastricht University, Maastricht, The Netherlands
| | - Theo Arts
- Department of Biomedical Engineering, Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, The Netherlands
| | - Harry J G M Crijns
- Department of Cardiology, Cardiovascular Research Institute Maastricht, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Frits W Prinzen
- Department of Physiology, Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, The Netherlands
| | - Tammo Delhaas
- Department of Biomedical Engineering, Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, The Netherlands
| | - Jordi Heijman
- Department of Cardiology, Cardiovascular Research Institute Maastricht, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Joost Lumens
- Department of Biomedical Engineering, Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, The Netherlands
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Balakin AA, Lukin ON, Kuznetsov DA, Protsenko YL. The Intracellular Calcium Kinetics and Action Potential in the Ventricular Myocardium of Spontaneously Hypertensive ISIAH Rats. Biophysics (Nagoya-shi) 2020. [DOI: 10.1134/s0006350920030021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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Lookin O, Kuznetsov D, Protsenko Y. Sex differences in stretch-dependent effects on tension and Ca(2+) transient of rat trabeculae in monocrotaline pulmonary hypertension. J Physiol Sci 2015; 65:89-98. [PMID: 25359385 PMCID: PMC10718032 DOI: 10.1007/s12576-014-0341-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2014] [Accepted: 10/03/2014] [Indexed: 10/24/2022]
Abstract
We aim to compare the effects of stretch on isometric tension/Ca(2+) transient in the right ventricular trabeculae of control (CONT) and hypertensive (MCT, monocrotaline application) adult male and female rats. The treatment with MCT resulted in RV hypertrophy in males only. Blunted active force-length relation and substantially prolonged twitch were found in MCT-males but not MCT-females (vs same-sex CONT). Ca(2+) transient was prolonged in both MCT-treated groups but extremely so in the MCT-males. The gradual stretch resulted in a distinct "bump" on Ca(2+) transient decline in CONT and MCT-treated groups. The integral magnitude of the "bump" was unaffected by the treatment with MCT in males or females but was larger in males vs females. The rate of "bump" development was significantly slower in MCT-males. In conclusion, the sex-specific differences in the stretch-dependent regulation of [Ca(2+)] i may underlie preservation of the Frank-Starling mechanism in female rat myocardium in monocrotaline-induced pulmonary hypertension.
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Affiliation(s)
- Oleg Lookin
- Laboratory of Biological Motility, Institute of Immunology and Physiology, Ural Branch of Russian Academy of Sciences, Yekaterinburg, 620049, Russia,
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