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Zheng J, Dooge HC, Valdivia HH, Alvarado FJ. Ablation of three major phospho-sites in RyR2 preserves the global adrenergic response but creates an arrhythmogenic substrate. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.07.08.602617. [PMID: 39026734 PMCID: PMC11257526 DOI: 10.1101/2024.07.08.602617] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/20/2024]
Abstract
Background Ryanodine receptor 2 (RyR2) is one of the first substrates undergoing phosphorylation upon catecholaminergic stimulation. Yet, the role of RyR2 phosphorylation in the adrenergic response remains debated. To date, three residues in RyR2 are known to undergo phosphorylation upon adrenergic stimulation. We generated a model of RyR2 phospho-ablation of all three canonical phospho-sites (RyR2-S2031A/S2808A/S2814A, triple phospho-mutant, TPM) to elucidate the role of phosphorylation at these residues in the adrenergic response. Methods Cardiac structure and function, cellular Ca 2+ dynamics and electrophysiology, and RyR2 channel activity both under basal conditions and under isoproterenol (Iso) stimulation were systematically evaluated. We used echocardiography and electrocardiography in anesthetized mice, single-cell Ca 2+ imaging and whole-cell patch clamp in isolated adult cardiomyocytes, and biochemical assays. Results Iso stimulation produced normal chronotropic and inotropic responses in TPM mice as well as an increase in the global Ca 2+ transients in isolated cardiomyocytes. Functional studies revealed fewer Ca 2+ sparks in permeabilized TPM myocytes, and reduced RyR2-mediated Ca 2+ leak in intact myocytes under Iso stimulation, suggesting that the canonical sites may regulate RyR2-mediated Ca 2+ leak. TPM mice also displayed increased propensity for arrhythmia. TPM myocytes were prone to develop early afterdepolarizations (EADs), which were abolished by chelating intracellular Ca 2+ with EGTA, indicating that EADs require SR Ca 2+ release. EADs were also blocked by a low concentration of tetrodotoxin, further suggesting reactivation of the sodium current ( I Na ) as the underlying cause. Conclusion Phosphorylation of the three canonical residues on RyR2 may not be essential for the global adrenergic responses. However, these sites play a vital role in maintaining electrical stability during catecholamine stimulation by fine-tuning RyR2-mediated Ca 2+ leak. These findings underscore the importance of RyR2 phosphorylation and a finite diastolic Ca 2+ leak in maintaining electrical stability during catecholamine stimulation.
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Leow JWH, Chan ECY. CYP2J2-mediated metabolism of arachidonic acid in heart: A review of its kinetics, inhibition and role in heart rhythm control. Pharmacol Ther 2024; 258:108637. [PMID: 38521247 DOI: 10.1016/j.pharmthera.2024.108637] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2023] [Revised: 02/06/2024] [Accepted: 03/11/2024] [Indexed: 03/25/2024]
Abstract
Cytochrome P450 2 J2 (CYP2J2) is primarily expressed extrahepatically and is the predominant epoxygenase in human cardiac tissues. This highlights its key role in the metabolism of endogenous substrates. Significant scientific interest lies in cardiac CYP2J2 metabolism of arachidonic acid (AA), an omega-6 polyunsaturated fatty acid, to regioisomeric bioactive epoxyeicosatrienoic acid (EET) metabolites that show cardioprotective effects including regulation of cardiac electrophysiology. From an in vitro perspective, the accurate characterization of the kinetics of CYP2J2 metabolism of AA including its inhibition and inactivation by drugs could be useful in facilitating in vitro-in vivo extrapolations to predict drug-AA interactions in drug discovery and development. In this review, background information on the structure, regulation and expression of CYP2J2 in human heart is presented alongside AA and EETs as its endogenous substrate and metabolites. The in vitro and in vivo implications of the kinetics of this endogenous metabolic pathway as well as its perturbation via inhibition and inactivation by drugs are elaborated. Additionally, the role of CYP2J2-mediated metabolism of AA to EETs in cardiac electrophysiology will be expounded.
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Affiliation(s)
- Jacqueline Wen Hui Leow
- Department of Pharmacy, Faculty of Science, National University of Singapore, 18 Science Drive 4, Singapore 117543, Singapore
| | - Eric Chun Yong Chan
- Department of Pharmacy, Faculty of Science, National University of Singapore, 18 Science Drive 4, Singapore 117543, Singapore.
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3
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Cooper BL, Salameh S, Posnack NG. Comparative cardiotoxicity assessment of bisphenol chemicals and estradiol using human induced pluripotent stem cell-derived cardiomyocytes. Toxicol Sci 2024; 198:273-287. [PMID: 38310357 PMCID: PMC10964748 DOI: 10.1093/toxsci/kfae015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2024] Open
Abstract
Bisphenol A (BPA) is commonly used to manufacture consumer and medical-grade plastics. Due to health concerns, BPA substitutes are being incorporated-including bisphenol S (BPS) and bisphenol F (BPF)-without a comprehensive understanding of their toxicological profile. Previous studies suggest that bisphenol chemicals perturb cardiac electrophysiology in a manner that is similar to 17β-estradiol (E2). We aimed to compare the effects of E2 with BPA, BPF, and BPS using human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CM). Cardiac parameters were evaluated using microelectrode array (MEA) technology and live-cell fluorescent imaging. Cardiac metrics remained relatively stable after exposure to nanomolar concentrations (1-1000 nM) of E2, BPA, BPF, or BPS. At higher micromolar concentrations, chemical exposures decreased the depolarization spike amplitude, and shortened the field potential, action potential duration, and calcium transient duration (E2 ≥ BPA ≥ BPF ≫ BPS). Cardiomyocyte physiology was largely undisturbed by BPS. BPA-induced effects were exaggerated when coadministered with an L-type calcium channel (LTCC) antagonist or E2, and reduced when coadministered with an LTCC agonist or an estrogen receptor alpha antagonist. E2-induced effects were not exaggerated by coadministration with an LTCC antagonist. Although the observed cardiac effects of E2 and BPA were similar, a few distinct differences suggest that these chemicals may act (in part) through different mechanisms. hiPSC-CM are a useful model for screening cardiotoxic chemicals, nevertheless, the described findings should be validated using a more complex ex vivo and/or in vivo model.
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Affiliation(s)
- Blake L Cooper
- Sheikh Zayed Institute for Pediatric Surgical Innovation, Children’s National Hospital, Washington, District of Columbia 20010, USA
- Children’s National Heart Institute, Children’s National Hospital, Washington, District of Columbia 20010, USA
- Department of Pharmacology & Physiology, School of Medicine & Health Sciences, The George Washington University, Washington, District of Columbia 20052, USA
| | - Shatha Salameh
- Sheikh Zayed Institute for Pediatric Surgical Innovation, Children’s National Hospital, Washington, District of Columbia 20010, USA
- Children’s National Heart Institute, Children’s National Hospital, Washington, District of Columbia 20010, USA
- Department of Pharmacology & Physiology, School of Medicine & Health Sciences, The George Washington University, Washington, District of Columbia 20052, USA
| | - Nikki Gillum Posnack
- Sheikh Zayed Institute for Pediatric Surgical Innovation, Children’s National Hospital, Washington, District of Columbia 20010, USA
- Children’s National Heart Institute, Children’s National Hospital, Washington, District of Columbia 20010, USA
- Department of Pharmacology & Physiology, School of Medicine & Health Sciences, The George Washington University, Washington, District of Columbia 20052, USA
- Department of Pediatrics, School of Medicine & Health Sciences, The George Washington University, Washington, District of Columbia 20052, USA
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4
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Power AS, Asamudo EU, Worthington LP, Alim CC, Parackal RE, Wallace RS, Ebenebe OV, Heller Brown J, Kohr MJ, Bers DM, Erickson JR. Nitric Oxide Modulates Ca 2+ Leak and Arrhythmias via S-Nitrosylation of CaMKII. Circ Res 2023; 133:1040-1055. [PMID: 37961889 PMCID: PMC10699507 DOI: 10.1161/circresaha.123.323571] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Revised: 10/29/2023] [Accepted: 10/31/2023] [Indexed: 11/15/2023]
Abstract
BACKGROUND Nitric oxide (NO) has been identified as a signaling molecule generated during β-adrenergic receptor stimulation in the heart. Furthermore, a role for NO in triggering spontaneous Ca2+ release via S-nitrosylation of CaMKIIδ (Ca2+/calmodulin kinase II delta) is emerging. NO donors are routinely used clinically for their cardioprotective effects on the heart, but it is unknown how NO donors modulate the proarrhythmic CaMKII to alter cardiac arrhythmia incidence. We test the role of S-nitrosylation of CaMKIIδ at the Cysteine-273 inhibitory site and cysteine-290 activating site in cardiac Ca2+ handling and arrhythmogenesis before and during β-adrenergic receptor stimulation. METHODS We measured Ca2+-handling in isolated cardiomyocytes from C57BL/6J wild-type (WT) mice and mice lacking CaMKIIδ expression (CaMKIIδ-KO) or with deletion of the S-nitrosylation site on CaMKIIδ at cysteine-273 or cysteine-290 (CaMKIIδ-C273S and -C290A knock-in mice). Cardiomyocytes were exposed to NO donors, S-nitrosoglutathione (GSNO; 150 μM), sodium nitroprusside (200 μM), and β-adrenergic agonist isoproterenol (100 nmol/L). RESULTS Both WT and CaMKIIδ-KO cardiomyocytes responded to isoproterenol with a full inotropic and lusitropic Ca2+ transient response as well as increased Ca2+ spark frequency. However, the increase in Ca2+ spark frequency was significantly attenuated in CaMKIIδ-KO cardiomyocytes. The protection from isoproterenol-induced Ca2+ sparks and waves was mimicked by GSNO pretreatment in WT cardiomyocytes but lost in CaMKIIδ-C273S cardiomyocytes. When GSNO was applied after isoproterenol, this protection was not observed in WT or CaMKIIδ-C273S but was apparent in CaMKIIδ-C290A. In Langendorff-perfused isolated hearts, GSNO pretreatment limited isoproterenol-induced arrhythmias in WT but not CaMKIIδ-C273S hearts, while GSNO exposure after isoproterenol sustained or exacerbated arrhythmic events. CONCLUSIONS We conclude that prior S-nitrosylation of CaMKIIδ at cysteine-273 can limit subsequent β-adrenergic receptor-induced arrhythmias, but that S-nitrosylation at cysteine-290 might worsen or sustain β-adrenergic receptor-induced arrhythmias. This has important implications for the administration of NO donors in the clinical setting.
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Affiliation(s)
- Amelia S. Power
- Department of Physiology and HeartOtago, University of Otago, Dunedin, New Zealand (A.S.P., E.U.A., L.P.I.W., R.E.P., R.S.W., J.R.E.)
- Department of Physiology, University of Auckland, New Zealand (A.S.P.)
| | - Esther U. Asamudo
- Department of Physiology and HeartOtago, University of Otago, Dunedin, New Zealand (A.S.P., E.U.A., L.P.I.W., R.E.P., R.S.W., J.R.E.)
- Department of Pharmacology, University of California, Davis (E.U.A., C.C.A., D.M.B.)
| | - Luke P.I. Worthington
- Department of Physiology and HeartOtago, University of Otago, Dunedin, New Zealand (A.S.P., E.U.A., L.P.I.W., R.E.P., R.S.W., J.R.E.)
| | - Chidera C. Alim
- Department of Pharmacology, University of California, Davis (E.U.A., C.C.A., D.M.B.)
| | - Raquel E. Parackal
- Department of Physiology and HeartOtago, University of Otago, Dunedin, New Zealand (A.S.P., E.U.A., L.P.I.W., R.E.P., R.S.W., J.R.E.)
| | - Rachel S. Wallace
- Department of Physiology and HeartOtago, University of Otago, Dunedin, New Zealand (A.S.P., E.U.A., L.P.I.W., R.E.P., R.S.W., J.R.E.)
| | - Obialunanma V. Ebenebe
- Department of Environmental Health and Engineering, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD (O.V.E., M.J.K.)
| | - Joan Heller Brown
- Department of Pharmacology, University of California, San Diego, La Jolla (J.H.B.)
| | - Mark J. Kohr
- Department of Environmental Health and Engineering, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD (O.V.E., M.J.K.)
| | - Donald M. Bers
- Department of Pharmacology, University of California, Davis (E.U.A., C.C.A., D.M.B.)
| | - Jeffrey R. Erickson
- Department of Physiology and HeartOtago, University of Otago, Dunedin, New Zealand (A.S.P., E.U.A., L.P.I.W., R.E.P., R.S.W., J.R.E.)
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Ghosheh M, Ehrlich A, Ioannidis K, Ayyash M, Goldfracht I, Cohen M, Fischer A, Mintz Y, Gepstein L, Nahmias Y. Electro-metabolic coupling in multi-chambered vascularized human cardiac organoids. Nat Biomed Eng 2023; 7:1493-1513. [PMID: 37550423 DOI: 10.1038/s41551-023-01071-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Accepted: 06/27/2023] [Indexed: 08/09/2023]
Abstract
The study of cardiac physiology is hindered by physiological differences between humans and small-animal models. Here we report the generation of multi-chambered self-paced vascularized human cardiac organoids formed under anisotropic stress and their applicability to the study of cardiac arrhythmia. Sensors embedded in the cardiac organoids enabled the simultaneous measurement of oxygen uptake, extracellular field potentials and cardiac contraction at resolutions higher than 10 Hz. This microphysiological system revealed 1 Hz cardiac respiratory cycles that are coupled to the electrical rather than the mechanical activity of cardiomyocytes. This electro-mitochondrial coupling was driven by mitochondrial calcium oscillations driving respiration cycles. Pharmaceutical or genetic inhibition of this coupling results in arrhythmogenic behaviour. We show that the chemotherapeutic mitoxantrone induces arrhythmia through disruption of this pathway, a process that can be partially reversed by the co-administration of metformin. Our microphysiological cardiac systems may further facilitate the study of the mitochondrial dynamics of cardiac rhythms and advance our understanding of human cardiac physiology.
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Affiliation(s)
- Mohammad Ghosheh
- Alexander Grass Center for Bioengineering, The Hebrew University of Jerusalem, Jerusalem, Israel
- The Rachel and Selim Benin School of Computer Science and Engineering, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Avner Ehrlich
- Alexander Grass Center for Bioengineering, The Hebrew University of Jerusalem, Jerusalem, Israel
- The Rachel and Selim Benin School of Computer Science and Engineering, The Hebrew University of Jerusalem, Jerusalem, Israel
- Tissue Dynamics, LTD, Jerusalem, Israel
| | - Konstantinos Ioannidis
- Alexander Grass Center for Bioengineering, The Hebrew University of Jerusalem, Jerusalem, Israel
- The Rachel and Selim Benin School of Computer Science and Engineering, The Hebrew University of Jerusalem, Jerusalem, Israel
- Tissue Dynamics, LTD, Jerusalem, Israel
| | - Muneef Ayyash
- Alexander Grass Center for Bioengineering, The Hebrew University of Jerusalem, Jerusalem, Israel
- The Rachel and Selim Benin School of Computer Science and Engineering, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Idit Goldfracht
- Sohnis Research Laboratory for Cardiac Electrophysiology and Regenerative Medicine, the Rappaport Faculty of Medicine and Research Institute, Technion- Israel Institute of Technology, Haifa, Israel
| | - Merav Cohen
- Alexander Grass Center for Bioengineering, The Hebrew University of Jerusalem, Jerusalem, Israel
- The Rachel and Selim Benin School of Computer Science and Engineering, The Hebrew University of Jerusalem, Jerusalem, Israel
- Department of Cell and Developmental Biology, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Amit Fischer
- Department of Biological Chemistry, Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Yoav Mintz
- Department of General Surgery, Hadassah Hebrew University Medical Center, Jerusalem, Israel
- Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel
| | - Lior Gepstein
- Sohnis Research Laboratory for Cardiac Electrophysiology and Regenerative Medicine, the Rappaport Faculty of Medicine and Research Institute, Technion- Israel Institute of Technology, Haifa, Israel
- Cardiology Department, Rambam Health Care Campus, Haifa, Israel
| | - Yaakov Nahmias
- Alexander Grass Center for Bioengineering, The Hebrew University of Jerusalem, Jerusalem, Israel.
- The Rachel and Selim Benin School of Computer Science and Engineering, The Hebrew University of Jerusalem, Jerusalem, Israel.
- Tissue Dynamics, LTD, Jerusalem, Israel.
- Department of Cell and Developmental Biology, The Hebrew University of Jerusalem, Jerusalem, Israel.
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Cooper BL, Salameh S, Posnack NG. Comparative cardiotoxicity assessment of bisphenol chemicals and estradiol using human induced pluripotent stem cell-derived cardiomyocytes. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.13.557564. [PMID: 37745451 PMCID: PMC10515916 DOI: 10.1101/2023.09.13.557564] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/26/2023]
Abstract
Background Bisphenol A (BPA) is commonly used to manufacture consumer and medical-grade plastics. Due to health concerns, BPA substitutes are being incorporated - including bisphenol S (BPS) and bisphenol F (BPF) - without a comprehensive understanding of their toxicological profile. Objective Previous studies suggest that bisphenol chemicals perturb cardiac electrophysiology in a manner that is similar to 17β-estradiol (E2). We aimed to compare the effects of E2 with BPA, BPF, and BPS using human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CM). Methods Cardiac parameters were evaluated using microelectrode array (MEA) technology and live-cell fluorescent imaging at baseline and in response to chemical exposure (0.001-100 μM). Results Cardiac metrics remained relatively stable after exposure to nanomolar concentrations (1-1,000 nM) of E2, BPA, BPF, or BPS. At higher micromolar concentrations, chemical exposures resulted in a decrease in the depolarizing spike amplitude, shorter field potential and action potential duration, shorter calcium transient duration, and decrease in hiPSC-CM contractility (E2 > BPA > BPF >> BPS). Cardiomyocyte physiology was largely undisturbed by BPS exposure. BPA-induced effects were exaggerated when co-administered with an L-type calcium channel antagonist (verapamil) or E2 - and reduced when co-administered with an L-type calcium channel agonist (Bay K8644) or an estrogen receptor alpha antagonist (MPP). E2-induced effects generally mirrored those of BPA, but were not exaggerated by co-administration with an L-type calcium channel antagonist. Discussion Collectively across multiple cardiac endpoints, E2 was the most potent and BPS was the least potent disruptor of hiPSC-CM function. Although the observed cardiac effects of E2 and BPA were similar, a few distinct differences suggest that these chemicals may act (in part) through different mechanisms. hiPSC-CM are a useful model for screening cardiotoxic chemicals, nevertheless, the described in vitro findings should be validated using a more complex ex vivo and/or in vivo model.
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Power AS, Asamudo E, Worthington LPI, Alim CC, Parackal R, Wallace RS, Ebenebe OV, Brown JH, Kohr MJ, Bers DM, Erickson JR. Nitric Oxide modulates spontaneous Ca 2+ release and ventricular arrhythmias during β-adrenergic signalling through S-nitrosylation of Calcium/Calmodulin dependent kinase II. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.23.554546. [PMID: 37662205 PMCID: PMC10473710 DOI: 10.1101/2023.08.23.554546] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/05/2023]
Abstract
Rationale Nitric oxide (NO) has been identified as a signalling molecule generated during β-adrenergic receptor (AR) stimulation in the heart. Furthermore, a role for NO in triggering spontaneous Ca2+ release via S-nitrosylation of Ca2+/calmodulin kinase II delta (CaMKIIδ) is emerging. NO donors are routinely used clinically for their cardioprotective effects in the heart, but it is unknown how NO donors modulate the pro-arrhythmic CaMKII to alter cardiac arrhythmia incidence. Objective We test the role of S-nitrosylation of CaMKIIδ at the Cys-273 inhibitory site and Cys-290 activating site in cardiac Ca2+ handling and arrhythmogenesis before and during β-AR stimulation. Methods and Results We measured Ca2+-handling in isolated cardiomyocytes from C57BL/6J wild-type (WT) mice and mice lacking CaMKIIδ expression (CaMKIIδ-KO) or with deletion of the S-nitrosylation site on CaMKIIδ at Cys-273 or Cys-290 (CaMKIIδ-C273S and -C290A knock-in mice). Cardiomyocytes were exposed to NO donors, S-nitrosoglutathione (GSNO; 150 μM), sodium nitroprusside (SNP; 200 μM) and/or β-adrenergic agonist isoproterenol (ISO; 100 nM). WT and CaMKIIδ-KO cardiomyocytes treated with GSNO showed no change in Ca2+ transient or spark properties under baseline conditions (0.5 Hz stimulation frequency). Both WT and CaMKIIδ-KO cardiomyocytes responded to ISO with a full inotropic and lusitropic Ca2+ transient response as well as increased Ca2+ spark frequency. However, the increase in Ca2+ spark frequency was significantly attenuated in CaMKIIδ-KO cardiomyocytes. The protection from ISO-induced Ca2+ sparks and waves was mimicked by GSNO pre-treatment in WT cardiomyocytes, but lost in CaMKIIδ-C273S cardiomyocytes that displayed a robust increase in Ca2+ waves. This observation is consistent with CaMKIIδ-C273 S-nitrosylation being critical in limiting ISO-induced arrhythmogenic sarcoplasmic reticulum Ca2+ leak. When GSNO was applied after ISO this protection was not observed in WT or CaMKIIδ-C273S but was apparent in CaMKIIδ-C290A. In Langendorff-perfused isolated hearts, GSNO pre-treatment limited ISO-induced arrhythmias in WT but not CaMKIIδ-C273S hearts, while GSNO exposure after ISO sustained or exacerbated arrhythmic events. Conclusions We conclude that prior S-nitrosylation of CaMKIIδ at Cys-273 can limit subsequent β-AR induced arrhythmias, but that S-nitrosylation at Cys-290 might worsen or sustain β-AR-induced arrhythmias. This has important implications for the administration of NO donors in the clinical setting.
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Affiliation(s)
- Amelia S. Power
- Department of Physiology and HeartOtago, University of Otago, Dunedin, New Zealand
- Department of Physiology, University of Auckland, Auckland, New Zealand
| | - Esther Asamudo
- Department of Physiology and HeartOtago, University of Otago, Dunedin, New Zealand
- Department of Pharmacology, University of California, Davis
| | | | | | - Raquel Parackal
- Department of Physiology and HeartOtago, University of Otago, Dunedin, New Zealand
| | - Rachel S. Wallace
- Department of Physiology and HeartOtago, University of Otago, Dunedin, New Zealand
| | - Obialunanma V. Ebenebe
- Department of Environmental Health and Engineering, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Joan Heller Brown
- Department of Pharmacology, University of California, San Diego, La Jolla
| | - Mark J. Kohr
- Department of Environmental Health and Engineering, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Donald M. Bers
- Department of Pharmacology, University of California, Davis
| | - Jeffrey R. Erickson
- Department of Physiology and HeartOtago, University of Otago, Dunedin, New Zealand
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Benson JM, Wang G, Hutt JA, Wu G, Kaminsky SM, Cram S, Barur R, Donahue JK. Preclinical safety and biodistribution assessment of Ad-KCNH2-G628S administered via atrial painting in New Zealand white rabbits. Basic Clin Pharmacol Toxicol 2023; 133:179-193. [PMID: 37177881 PMCID: PMC10935599 DOI: 10.1111/bcpt.13885] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Revised: 04/27/2023] [Accepted: 05/02/2023] [Indexed: 05/15/2023]
Abstract
Post-operative atrial fibrillation (POAF) is the most common complication after cardiac surgery. Despite implementation of several pharmacological strategies, incidence of POAF remains at approximately 30%. An adenovirus vector encoding KCNH2-G628S has proven efficacious in a porcine model of AF. In this preclinical study, 1.5 × 1010 or 1.5 × 1012 Ad-KCNH2-G628S vector particles (vp) were applied to the atrial epicardium or 1.5 × 1012 vp were applied to the whole epicardial surface of New Zealand White rabbits. Saline and vector vehicle served as procedure controls. Animals were followed for up to 42 days. Vector genomes persisted in the atria up to 42 days, with no distribution to extra-thoracic organs. There were no adverse effects attributable to test article on standard toxicological endpoints or on blood pressure, left atrial or ventricular ejection fractions, electrocardiographic parameters, or serum IL-6 or troponin concentrations. Mononuclear infiltration of the myocardium of the atrial free walls of low-dose, but not high-dose animals was observed at 7 and 21 days, but these changes did not persist or affect cardiac function. After scaling for heart size, results indicate the test article is safe at doses up to 25 times the maximum proposed for the human clinical trial.
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Affiliation(s)
- Janet M. Benson
- Applied Toxicology Program, Lovelace Biomedical Research Institute, Albuquerque, NM 87108, USA
| | - Gensheng Wang
- Applied Toxicology Program, Lovelace Biomedical Research Institute, Albuquerque, NM 87108, USA
- Baxter International, Inc. Deerfield, IL 60015, USA
| | - Julie A. Hutt
- Greenfield Pathology Services, Inc., Greenfield, IN 46140, USA
| | - Guodong Wu
- Applied Toxicology Program, Lovelace Biomedical Research Institute, Albuquerque, NM 87108, USA
| | - Stephen M. Kaminsky
- Weill Cornell Medicine, Belfer Gene Therapy Core Facility, New York, NY 10021, USA
| | - Sara Cram
- Weill Cornell Medicine, Belfer Gene Therapy Core Facility, New York, NY 10021, USA
| | - Rajeshkumar Barur
- Cardiovascular Medicine, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
| | - J. Kevin Donahue
- Cardiovascular Medicine, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
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9
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Salameh S, Ogueri V, Posnack NG. Adapting to a new environment: postnatal maturation of the human cardiomyocyte. J Physiol 2023; 601:2593-2619. [PMID: 37031380 PMCID: PMC10775138 DOI: 10.1113/jp283792] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Accepted: 03/16/2023] [Indexed: 04/10/2023] Open
Abstract
The postnatal mammalian heart undergoes remarkable developmental changes, which are stimulated by the transition from the intrauterine to extrauterine environment. With birth, increased oxygen levels promote metabolic, structural and biophysical maturation of cardiomyocytes, resulting in mature muscle with increased efficiency, contractility and electrical conduction. In this Topical Review article, we highlight key studies that inform our current understanding of human cardiomyocyte maturation. Collectively, these studies suggest that human atrial and ventricular myocytes evolve quickly within the first year but might not reach a fully mature adult phenotype until nearly the first decade of life. However, it is important to note that fetal, neonatal and paediatric cardiac physiology studies are hindered by a number of limitations, including the scarcity of human tissue, small sample size and a heavy reliance on diseased tissue samples, often without age-matched healthy controls. Future developmental studies are warranted to expand our understanding of normal cardiac physiology/pathophysiology and inform age-appropriate treatment strategies for cardiac disease.
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Affiliation(s)
- Shatha Salameh
- Department of Pharmacology & Physiology, George Washington University, Washington, DC, USA
- Sheikh Zayed Institute for Pediatric Surgical Innovation, Children’s National Hospital, Washington, DC, USA
| | - Vanessa Ogueri
- Children’s National Heart Institute, Children’s National Hospital, Washington, DC, USA
| | - Nikki Gillum Posnack
- Department of Pharmacology & Physiology, George Washington University, Washington, DC, USA
- Sheikh Zayed Institute for Pediatric Surgical Innovation, Children’s National Hospital, Washington, DC, USA
- Children’s National Heart Institute, Children’s National Hospital, Washington, DC, USA
- Department of Pediatrics, George Washington University, Washington, DC, USA
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10
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Haq KT, Cooper BL, Berk F, Posnack NG. The effect of sex and age on ex vivo cardiac electrophysiology: insight from a guinea pig model. Am J Physiol Heart Circ Physiol 2023; 324:H141-H154. [PMID: 36487188 PMCID: PMC9829463 DOI: 10.1152/ajpheart.00497.2022] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Revised: 11/30/2022] [Accepted: 12/02/2022] [Indexed: 12/14/2022]
Abstract
Highlighting the importance of sex as a biological variable, we recently reported sex differences in guinea pig in vivo electrocardiogram (ECG) measurements. However, substantial inconsistencies exist in this animal model, with conflicting reports of sex-specific differences in cardiac electrophysiology observed in vivo and in vitro. Herein, we evaluated whether sexual dimorphism persists in ex vivo preparations, using an isolated intact heart preparation. Pseudo-ECG recordings were collected in conjunction with dual optical mapping of transmembrane voltage and intracellular calcium from Langendorff-perfused hearts. In contrast to our in vivo results, we did not observe sex-specific differences in ECG parameters collected from isolated hearts. Furthermore, we observed significant age-specific differences in action potential duration (APD) and Ca2+ transient duration (CaD) during both normal sinus rhythm (NSR) and in response to dynamic pacing but only a modest sex-specific difference in CaD30. Similarly, the alternans fluctuation coefficient, conduction velocity during sinus rhythm or in response to pacing, and electrophysiology parameters (atrioventricular nodal effective refractory period, Wenckebach cycle length) were comparable between males and females. Results of our study suggest that the observed sex-specific differences in in vivo ECG parameters from guinea pigs are diminished in ex vivo isolated heart preparations, although age-specific patterns are prevalent. To assess sex as a biological variable in cardiac electrophysiology, a comprehensive approach may be necessary using both in vitro measurements from cardiomyocyte or intact heart preparations with secondary follow-up in vivo studies.NEW & NOTEWORTHY We evaluated whether the guinea pig heart has intrinsic sex-specific differences in cardiac electrophysiology. Although we observed sex-specific differences in in vivo ECGs, these differences did not persist ex vivo. Using a whole heart model, we observed similar APD, CaD, conduction velocity, and alternans susceptibility in males and females. We conclude that sex-specific differences in guinea pig cardiac electrophysiology are likely influenced by the in vivo environment and less dependent on the intrinsic electrical properties of the heart.
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Affiliation(s)
- Kazi T Haq
- Sheikh Zayed Institute for Pediatric Surgical Innovation, Children's National Hospital, Washington, District of Columbia
- Children's National Heart Institute, Children's National Hospital, Washington, District of Columbia
| | - Blake L Cooper
- Sheikh Zayed Institute for Pediatric Surgical Innovation, Children's National Hospital, Washington, District of Columbia
- Children's National Heart Institute, Children's National Hospital, Washington, District of Columbia
- Department of Pharmacology and Physiology, The George Washington University, Washington, District of Columbia
| | - Fiona Berk
- Sheikh Zayed Institute for Pediatric Surgical Innovation, Children's National Hospital, Washington, District of Columbia
- Children's National Heart Institute, Children's National Hospital, Washington, District of Columbia
- Department of Pharmacology and Physiology, The George Washington University, Washington, District of Columbia
- Department of Biomedical Engineering, The George Washington University, Washington, District of Columbia
| | - Nikki Gillum Posnack
- Sheikh Zayed Institute for Pediatric Surgical Innovation, Children's National Hospital, Washington, District of Columbia
- Children's National Heart Institute, Children's National Hospital, Washington, District of Columbia
- Department of Pharmacology and Physiology, The George Washington University, Washington, District of Columbia
- Department of Pediatrics, The George Washington University, Washington, District of Columbia
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11
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Ripplinger CM, Glukhov AV, Kay MW, Boukens BJ, Chiamvimonvat N, Delisle BP, Fabritz L, Hund TJ, Knollmann BC, Li N, Murray KT, Poelzing S, Quinn TA, Remme CA, Rentschler SL, Rose RA, Posnack NG. Guidelines for assessment of cardiac electrophysiology and arrhythmias in small animals. Am J Physiol Heart Circ Physiol 2022; 323:H1137-H1166. [PMID: 36269644 PMCID: PMC9678409 DOI: 10.1152/ajpheart.00439.2022] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Revised: 10/11/2022] [Accepted: 10/17/2022] [Indexed: 01/09/2023]
Abstract
Cardiac arrhythmias are a major cause of morbidity and mortality worldwide. Although recent advances in cell-based models, including human-induced pluripotent stem cell-derived cardiomyocytes (iPSC-CM), are contributing to our understanding of electrophysiology and arrhythmia mechanisms, preclinical animal studies of cardiovascular disease remain a mainstay. Over the past several decades, animal models of cardiovascular disease have advanced our understanding of pathological remodeling, arrhythmia mechanisms, and drug effects and have led to major improvements in pacing and defibrillation therapies. There exist a variety of methodological approaches for the assessment of cardiac electrophysiology and a plethora of parameters may be assessed with each approach. This guidelines article will provide an overview of the strengths and limitations of several common techniques used to assess electrophysiology and arrhythmia mechanisms at the whole animal, whole heart, and tissue level with a focus on small animal models. We also define key electrophysiological parameters that should be assessed, along with their physiological underpinnings, and the best methods with which to assess these parameters.
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Affiliation(s)
- Crystal M Ripplinger
- Department of Pharmacology, University of California Davis School of Medicine, Davis, California
| | - Alexey V Glukhov
- Department of Medicine, Cardiovascular Medicine, University of Wisconsin-Madison School of Medicine and Public Health, Madison, Wisconsin
| | - Matthew W Kay
- Department of Biomedical Engineering, The George Washington University, Washington, District of Columbia
| | - Bastiaan J Boukens
- Department Physiology, University Maastricht, Maastricht University Medical Center, Maastricht, The Netherlands
- Department of Medical Biology, University of Amsterdam, Amsterdam University Medical Center, Amsterdam, The Netherlands
| | - Nipavan Chiamvimonvat
- Department of Pharmacology, University of California Davis School of Medicine, Davis, California
- Department of Internal Medicine, University of California Davis School of Medicine, Davis, California
- Veterans Affairs Northern California Healthcare System, Mather, California
| | - Brian P Delisle
- Department of Physiology, University of Kentucky, Lexington, Kentucky
| | - Larissa Fabritz
- University Center of Cardiovascular Science, University Heart and Vascular Center, University Hospital Hamburg-Eppendorf with DZHK Hamburg/Kiel/Luebeck, Germany
- Institute of Cardiovascular Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Thomas J Hund
- Department of Internal Medicine, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio
- Department of Biomedical Engineering, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio
| | - Bjorn C Knollmann
- Vanderbilt Center for Arrhythmia Research and Therapeutics, Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Na Li
- Department of Medicine, Baylor College of Medicine, Houston, Texas
| | - Katherine T Murray
- Departments of Medicine and Pharmacology, Vanderbilt University School of Medicine, Nashville, Tennessee
| | - Steven Poelzing
- Virginia Tech Carilon School of Medicine, Center for Heart and Reparative Medicine Research, Fralin Biomedical Research Institute at Virginia Tech, Roanoke, Virginia
- Department of Biomedical Engineering and Mechanics, Virginia Polytechnic Institute and State University, Blacksburg, Virginia
| | - T Alexander Quinn
- Department of Physiology and Biophysics, Dalhousie University, Halifax, Nova Scotia, Canada
- School of Biomedical Engineering, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Carol Ann Remme
- Department of Experimental Cardiology, Heart Centre, Amsterdam Cardiovascular Sciences, Heart Failure and Arrhythmias Amsterdam UMC Location University of Amsterdam, Amsterdam, The Netherlands
| | - Stacey L Rentschler
- Cardiovascular Division, Department of Medicine, Washington University in Saint Louis, School of Medicine, Saint Louis, Missouri
| | - Robert A Rose
- Department of Cardiac Sciences, Libin Cardiovascular Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
- Department of Physiology and Pharmacology, Libin Cardiovascular Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Nikki G Posnack
- Sheikh Zayed Institute for Pediatric Surgical Innovation, Children's National Hospital, Washington, District of Columbia
- Department of Pediatrics, George Washington University School of Medicine, Washington, District of Columbia
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12
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Verkerk AO, Doszpod IJ, Mengarelli I, Magyar T, Polyák A, Pászti B, Efimov IR, Wilders R, Koncz I. Acetylcholine Reduces L-Type Calcium Current without Major Changes in Repolarization of Canine and Human Purkinje and Ventricular Tissue. Biomedicines 2022; 10:biomedicines10112987. [PMID: 36428555 PMCID: PMC9687254 DOI: 10.3390/biomedicines10112987] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Revised: 11/11/2022] [Accepted: 11/17/2022] [Indexed: 11/24/2022] Open
Abstract
Vagal nerve stimulation (VNS) holds a strong basis as a potentially effective treatment modality for chronic heart failure, which explains why a multicenter VNS study in heart failure with reduced ejection fraction is ongoing. However, more detailed information is required on the effect of acetylcholine (ACh) on repolarization in Purkinje and ventricular cardiac preparations to identify the advantages, risks, and underlying cellular mechanisms of VNS. Here, we studied the effect of ACh on the action potential (AP) of canine Purkinje fibers (PFs) and several human ventricular preparations. In addition, we characterized the effects of ACh on the L-type Ca2+ current (ICaL) and AP of human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) and performed computer simulations to explain the observed effects. Using microelectrode recordings, we found a small but significant AP prolongation in canine PFs. In the human myocardium, ACh slightly prolonged the AP in the midmyocardium but resulted in minor AP shortening in subepicardial tissue. Perforated patch-clamp experiments on hiPSC-CMs demonstrated that 5 µM ACh caused an ≈15% decrease in ICaL density without changes in gating properties. Using dynamic clamp, we found that under blocked K+ currents, 5 µM ACh resulted in an ≈23% decrease in AP duration at 90% of repolarization in hiPSC-CMs. Computer simulations using the O'Hara-Rudy human ventricular cell model revealed that the overall effect of ACh on AP duration is a tight interplay between the ACh-induced reduction in ICaL and ACh-induced changes in K+ currents. In conclusion, ACh results in minor changes in AP repolarization and duration of canine PFs and human ventricular myocardium due to the concomitant inhibition of inward ICaL and outward K+ currents, which limits changes in net repolarizing current and thus prevents major changes in AP repolarization.
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Affiliation(s)
- Arie O. Verkerk
- Department of Experimental Cardiology, Heart Center, Amsterdam Cardiovascular Sciences, Amsterdam UMC, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands
- Department of Medical Biology, Amsterdam Cardiovascular Sciences, Amsterdam UMC, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands
| | - Illés J. Doszpod
- Department of Pharmacology and Pharmacotherapy, Albert Szent-Györgyi Medical School, University of Szeged, 6721 Szeged, Hungary
| | - Isabella Mengarelli
- Department of Experimental Cardiology, Heart Center, Amsterdam Cardiovascular Sciences, Amsterdam UMC, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands
| | - Tibor Magyar
- Department of Pharmacology and Pharmacotherapy, Albert Szent-Györgyi Medical School, University of Szeged, 6721 Szeged, Hungary
| | - Alexandra Polyák
- Department of Pharmacology and Pharmacotherapy, Albert Szent-Györgyi Medical School, University of Szeged, 6721 Szeged, Hungary
| | - Bence Pászti
- Department of Pharmacology and Pharmacotherapy, Albert Szent-Györgyi Medical School, University of Szeged, 6721 Szeged, Hungary
| | - Igor R. Efimov
- Department of Biomedical Engineering, The George Washington University, Washington, DC 20052, USA
- Department of Biomedical Engineering, Northwestern University, Chicago, IL 60611, USA
- Department of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Ronald Wilders
- Department of Medical Biology, Amsterdam Cardiovascular Sciences, Amsterdam UMC, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands
- Correspondence: (R.W.); (I.K.)
| | - István Koncz
- Department of Pharmacology and Pharmacotherapy, Albert Szent-Györgyi Medical School, University of Szeged, 6721 Szeged, Hungary
- Department of Biomedical Engineering, The George Washington University, Washington, DC 20052, USA
- Correspondence: (R.W.); (I.K.)
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13
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Doste R, Coppini R, Bueno-Orovio A. Remodelling of potassium currents underlies arrhythmic action potential prolongation under beta-adrenergic stimulation in hypertrophic cardiomyopathy. J Mol Cell Cardiol 2022; 172:120-131. [PMID: 36058298 DOI: 10.1016/j.yjmcc.2022.08.361] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 08/15/2022] [Accepted: 08/27/2022] [Indexed: 12/14/2022]
Abstract
Hypertrophic cardiomyopathy (HCM) patients often present an enhanced arrhythmogenicity that can lead to lethal arrhythmias, especially during exercise. Recent studies have indicated an abnormal response of HCM cardiomyocytes to β-adrenergic receptor stimulation (β-ARS), with prolongation of their action potential rather than shortening. The mechanisms underlying this aberrant response to sympathetic stimulation and its possible proarrhythmic role remain unknown. The aims of this study are to investigate the key ionic mechanisms underlying the HCM abnormal response to β-ARS and the resultant repolarisation abnormalities using human-based experimental and computational methodologies. We integrated and calibrated the latest models of human ventricular electrophysiology and β-ARS using experimental measurements of human adult cardiomyocytes from control and HCM patients. Our major findings include: (1) the developed in silico models of β-ARS capture the behaviour observed in the experimental data, including the aberrant response of HCM cardiomyocytes to β-ARS; (2) the reduced increase of potassium currents under β-ARS was identified as the main mechanism of action potential prolongation in HCM, rather than a more sustained inward calcium current; (3) action potential duration differences between healthy and HCM cardiomyocytes were increased upon β-ARS, while endocardial to epicardial differences in HCM cardiomyocytes were reduced; (4) models presenting repolarisation abnormalities were characterised by downregulation of the rapid delayed rectifier potassium current and the sodium‑potassium pump, while inward currents were upregulated. In conclusion, our results identify causal relationships between the HCM phenotype and its arrhythmogenic response to β-ARS through the downregulation of potassium currents.
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Affiliation(s)
- Ruben Doste
- Department of Computer Science, BHF Centre of Research Excellence, University of Oxford, Oxford, United Kingdom
| | | | - Alfonso Bueno-Orovio
- Department of Computer Science, BHF Centre of Research Excellence, University of Oxford, Oxford, United Kingdom.
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14
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Widatalla N, Funamoto K, Kawataki M, Yoshida C, Funamoto K, Saito M, Kasahara Y, Khandoker A, Kimura Y. Model-based estimation of QT intervals of mouse fetal electrocardiogram. Biomed Eng Online 2022; 21:45. [PMID: 35768841 PMCID: PMC9245267 DOI: 10.1186/s12938-022-01015-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Accepted: 06/20/2022] [Indexed: 11/21/2022] Open
Abstract
Background Abnormal prolongation in the QT interval or long QT syndrome (LQTS) is associated with several cardiac complications such as sudden infant death syndrome (SIDS). LQTS is believed to be linked to genetic mutations which can be understood by using animal models, such as mice models. Nevertheless, the research related to fetal QT interval in mice is still limited because of challenges associated with T wave measurements in fetal electrocardiogram (fECG). Reliable measurement of T waves is essential for estimating their end timings for QT interval assessment. Results A mathematical model was used to estimate QT intervals. Estimated QT intervals were validated with Q-aortic closure (Q-Ac) intervals of Doppler ultrasound (DUS) and comparison between both showed good agreement with a correlation coefficient higher than 0.88 (r > 0.88, P < 0.05). Conclusion Model-based estimation of QT intervals can help in better understanding of QT intervals in fetal mice.
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Affiliation(s)
- Namareq Widatalla
- School of Medicine, Tohoku University, 2-1 Seiryo-machi, Aoba-ku, Sendai, Miyagi, 980-8575, Japan.
| | | | | | - Chihiro Yoshida
- School of Medicine, Tohoku University, 2-1 Seiryo-machi, Aoba-ku, Sendai, Miyagi, 980-8575, Japan
| | - Kenichi Funamoto
- School of Medicine, Tohoku University, 2-1 Seiryo-machi, Aoba-ku, Sendai, Miyagi, 980-8575, Japan
| | - Masatoshi Saito
- School of Medicine, Tohoku University, 2-1 Seiryo-machi, Aoba-ku, Sendai, Miyagi, 980-8575, Japan
| | - Yoshiyuki Kasahara
- School of Medicine, Tohoku University, 2-1 Seiryo-machi, Aoba-ku, Sendai, Miyagi, 980-8575, Japan
| | | | - Yoshitaka Kimura
- School of Medicine, Tohoku University, 2-1 Seiryo-machi, Aoba-ku, Sendai, Miyagi, 980-8575, Japan
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15
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Xia R, Tomsits P, Loy S, Zhang Z, Pauly V, Schüttler D, Clauss S. Cardiac Macrophages and Their Effects on Arrhythmogenesis. Front Physiol 2022; 13:900094. [PMID: 35812333 PMCID: PMC9257039 DOI: 10.3389/fphys.2022.900094] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2022] [Accepted: 05/30/2022] [Indexed: 12/24/2022] Open
Abstract
Cardiac electrophysiology is a complex system established by a plethora of inward and outward ion currents in cardiomyocytes generating and conducting electrical signals in the heart. However, not only cardiomyocytes but also other cell types can modulate the heart rhythm. Recently, cardiac macrophages were demonstrated as important players in both electrophysiology and arrhythmogenesis. Cardiac macrophages are a heterogeneous group of immune cells including resident macrophages derived from embryonic and fetal precursors and recruited macrophages derived from circulating monocytes from the bone marrow. Recent studies suggest antiarrhythmic as well as proarrhythmic effects of cardiac macrophages. The proposed mechanisms of how cardiac macrophages affect electrophysiology vary and include both direct and indirect interactions with other cardiac cells. In this review, we provide an overview of the different subsets of macrophages in the heart and their possible interactions with cardiomyocytes under both physiologic conditions and heart disease. Furthermore, we elucidate similarities and differences between human, murine and porcine cardiac macrophages, thus providing detailed information for researchers investigating cardiac macrophages in important animal species for electrophysiologic research. Finally, we discuss the pros and cons of mice and pigs to investigate the role of cardiac macrophages in arrhythmogenesis from a translational perspective.
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Affiliation(s)
- Ruibing Xia
- Department of Medicine I, University Hospital Munich, Ludwig-Maximilians-University Munich (LMU), Munich, Germany
- Institute of Surgical Research at the Walter-Brendel-Centre of Experimental Medicine, University Hospital Munich, Ludwig-Maximilians-University Munich (LMU), Munich, Germany
- German Centre for Cardiovascular Research (DZHK), Partner Site Munich, Munich Heart Alliance, Munich, Germany
| | - Philipp Tomsits
- Department of Medicine I, University Hospital Munich, Ludwig-Maximilians-University Munich (LMU), Munich, Germany
- Institute of Surgical Research at the Walter-Brendel-Centre of Experimental Medicine, University Hospital Munich, Ludwig-Maximilians-University Munich (LMU), Munich, Germany
- German Centre for Cardiovascular Research (DZHK), Partner Site Munich, Munich Heart Alliance, Munich, Germany
| | - Simone Loy
- Department of Medicine I, University Hospital Munich, Ludwig-Maximilians-University Munich (LMU), Munich, Germany
- Institute of Surgical Research at the Walter-Brendel-Centre of Experimental Medicine, University Hospital Munich, Ludwig-Maximilians-University Munich (LMU), Munich, Germany
- German Centre for Cardiovascular Research (DZHK), Partner Site Munich, Munich Heart Alliance, Munich, Germany
| | - Zhihao Zhang
- Department of Medicine I, University Hospital Munich, Ludwig-Maximilians-University Munich (LMU), Munich, Germany
- Institute of Surgical Research at the Walter-Brendel-Centre of Experimental Medicine, University Hospital Munich, Ludwig-Maximilians-University Munich (LMU), Munich, Germany
- German Centre for Cardiovascular Research (DZHK), Partner Site Munich, Munich Heart Alliance, Munich, Germany
| | - Valerie Pauly
- Department of Medicine I, University Hospital Munich, Ludwig-Maximilians-University Munich (LMU), Munich, Germany
- Institute of Surgical Research at the Walter-Brendel-Centre of Experimental Medicine, University Hospital Munich, Ludwig-Maximilians-University Munich (LMU), Munich, Germany
- German Centre for Cardiovascular Research (DZHK), Partner Site Munich, Munich Heart Alliance, Munich, Germany
| | - Dominik Schüttler
- Department of Medicine I, University Hospital Munich, Ludwig-Maximilians-University Munich (LMU), Munich, Germany
- Institute of Surgical Research at the Walter-Brendel-Centre of Experimental Medicine, University Hospital Munich, Ludwig-Maximilians-University Munich (LMU), Munich, Germany
- German Centre for Cardiovascular Research (DZHK), Partner Site Munich, Munich Heart Alliance, Munich, Germany
| | - Sebastian Clauss
- Department of Medicine I, University Hospital Munich, Ludwig-Maximilians-University Munich (LMU), Munich, Germany
- Institute of Surgical Research at the Walter-Brendel-Centre of Experimental Medicine, University Hospital Munich, Ludwig-Maximilians-University Munich (LMU), Munich, Germany
- German Centre for Cardiovascular Research (DZHK), Partner Site Munich, Munich Heart Alliance, Munich, Germany
- *Correspondence: Sebastian Clauss,
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16
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Haq KT, Cooper BL, Berk F, Roberts A, Swift LM, Posnack NG. Demographic and Methodological Heterogeneity in Electrocardiogram Signals From Guinea Pigs. Front Physiol 2022; 13:925042. [PMID: 35721548 PMCID: PMC9202081 DOI: 10.3389/fphys.2022.925042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Accepted: 05/09/2022] [Indexed: 11/24/2022] Open
Abstract
Electrocardiograms (ECG) are universally used to measure the electrical activity of the heart; however, variations in recording techniques and/or subject demographics can affect ECG interpretation. In this study, we investigated variables that are likely to influence ECG metric measurements in cardiovascular research, including recording technique, use of anesthesia, and animal model characteristics. Awake limb lead ECG recordings were collected in vivo from adult guinea pigs using a platform ECG system, while recordings in anesthetized animals were performed using both a platform and needle ECG system. We report significant heterogeneities in ECG metric values that are attributed to methodological differences (e.g., ECG lead configuration, ECG recording platform, presence or absence of anesthesia) that persist even within the same cohort of animals. Further, we report that variability in animal demographics is preserved in vivo ECG recordings—with animal age serving as a significant contributor, while sex-specific influences were less pronounced. Methodological approaches and subject demographics should be fully considered when interpreting ECG values in animal models, comparing datasets between studies, or developing artificial intelligence algorithms that utilize an ECG database.
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Affiliation(s)
- Kazi T. Haq
- Sheikh Zayed Institute for Pediatric Surgical Innovation, Washington D.C., DC, United States
- Children’s National Heart Institute, Washington D.C., DC, United States
| | - Blake L. Cooper
- Sheikh Zayed Institute for Pediatric Surgical Innovation, Washington D.C., DC, United States
- Children’s National Heart Institute, Washington D.C., DC, United States
- Department of Pharmacology & Physiology, Washington D.C., DC, United States
| | - Fiona Berk
- Sheikh Zayed Institute for Pediatric Surgical Innovation, Washington D.C., DC, United States
| | - Anysja Roberts
- Sheikh Zayed Institute for Pediatric Surgical Innovation, Washington D.C., DC, United States
- Children’s National Heart Institute, Washington D.C., DC, United States
| | - Luther M. Swift
- Sheikh Zayed Institute for Pediatric Surgical Innovation, Washington D.C., DC, United States
- Children’s National Heart Institute, Washington D.C., DC, United States
| | - Nikki Gillum Posnack
- Sheikh Zayed Institute for Pediatric Surgical Innovation, Washington D.C., DC, United States
- Children’s National Heart Institute, Washington D.C., DC, United States
- Department of Pharmacology & Physiology, Washington D.C., DC, United States
- Department of Pediatrics, Washington D.C., DC, United States
- *Correspondence: Nikki Gillum Posnack,
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17
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Biasi N, Seghetti P, Tognetti A. Diffuse fibrosis and repolarization disorders explain ventricular arrhythmias in Brugada syndrome: a computational study. Sci Rep 2022; 12:8530. [PMID: 35595775 PMCID: PMC9123016 DOI: 10.1038/s41598-022-12239-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Accepted: 05/06/2022] [Indexed: 11/20/2022] Open
Abstract
In this work, we reported a computational study to quantitatively determine the individual contributions of three candidate arrhythmic factors associated with Brugada Syndrome. In particular, we focused our analysis on the role of structural abnormalities, dispersion of repolarization, and size of the diseased region. We developed a human phenomenological model capable of replicating the action potential characteristics both in Brugada Syndrome and in healthy conditions. Inspired by physiological observations, we employed the phenomenological model in a 2D geometry resembling the pathological RVOT coupled with healthy epicardial tissue. We assessed the insurgence of sustained reentry as a function of electrophysiological and structural abnormalities. Our computational study indicates that both structural and repolarization abnormalities are essential to induce sustained reentry. Furthermore, our results suggest that neither dispersion of repolarization nor structural abnormalities are sufficient on their own to induce sustained reentry. It should be noted how our study seems to explain an arrhythmic mechanism that unifies the classic repolarization and depolarization hypotheses of the pathophysiology of the Brugada Syndrome. Finally, we believe that this work may offer a new perspective on the computational and clinical investigation of Brugada Syndrome and its arrhythmic behaviour.
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Affiliation(s)
- Niccoló Biasi
- Department of Information Engineering, University of Pisa, Pisa, Italy.
| | - Paolo Seghetti
- Institute of Life Sciences, Scuola Superiore Sant'Anna, Pisa, Italy.,National Research Council, Institute of Clinical Physiology, Pisa, Italy
| | - Alessandro Tognetti
- Department of Information Engineering, University of Pisa, Pisa, Italy.,Research Centre "E. Piaggio", University of Pisa, Pisa, Italy
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18
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Fassina D, Costa CM, Longobardi S, Karabelas E, Plank G, Harding SE, Niederer SA. Modelling the interaction between stem cells derived cardiomyocytes patches and host myocardium to aid non-arrhythmic engineered heart tissue design. PLoS Comput Biol 2022; 18:e1010030. [PMID: 35363778 PMCID: PMC9007348 DOI: 10.1371/journal.pcbi.1010030] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Revised: 04/13/2022] [Accepted: 03/17/2022] [Indexed: 11/18/2022] Open
Abstract
Application of epicardial patches constructed from human-induced pluripotent stem cell- derived cardiomyocytes (hiPSC-CMs) has been proposed as a long-term therapy to treat scarred hearts post myocardial infarction (MI). Understanding electrical interaction between engineered heart tissue patches (EHT) and host myocardium represents a key step toward a successful patch engraftment. EHT retain different electrical properties with respect to the host heart tissue due to the hiPSC-CMs immature phenotype, which may lead to increased arrhythmia risk. We developed a modelling framework to examine the influence of patch design on electrical activation at the engraftment site. We performed an in silico investigation of different patch design approaches to restore pre-MI activation properties and evaluated the associated arrhythmic risk. We developed an in silico cardiac electrophysiology model of a transmural cross section of host myocardium. The model featured an infarct region, an epicardial patch spanning the infarct region and a bath region. The patch is modelled as a layer of hiPSC-CM, combined with a layer of conductive polymer (CP). Tissue and patch geometrical dimensions and conductivities were incorporated through 10 modifiable model parameters. We validated our model against 4 independent experimental studies and showed that it can qualitatively reproduce their findings. We performed a global sensitivity analysis (GSA) to isolate the most important parameters, showing that the stimulus propagation is mainly governed by the scar depth, radius and conductivity when the scar is not transmural, and by the EHT patch conductivity when the scar is transmural. We assessed the relevance of small animal studies to humans by comparing simulations of rat, rabbit and human myocardium. We found that stimulus propagation paths and GSA sensitivity indices are consistent across species. We explored which EHT design variables have the potential to restore physiological propagation. Simulations predict that increasing EHT conductivity from 0.28 to 1-1.1 S/m recovered physiological activation in rat, rabbit and human. Finally, we assessed arrhythmia risk related to increasing EHT conductivity and tested increasing the EHT Na+ channel density as an alternative strategy to match healthy activation. Our results revealed a greater arrhythmia risk linked to increased EHT conductivity compared to increased Na+ channel density. We demonstrated that our modeling framework could capture the interaction between host and EHT patches observed in in vitro experiments. We showed that large (patch and tissue dimensions) and small (cardiac myocyte electrophysiology) scale differences between small animals and humans do not alter EHT patch effect on infarcted tissue. Our model revealed that only when the scar is transmural do EHT properties impact activation times and isolated the EHT conductivity as the main parameter influencing propagation. We predicted that restoring physiological activation by tuning EHT conductivity is possible but may promote arrhythmic behavior. Finally, our model suggests that acting on hiPSC-CMs low action potential upstroke velocity and lack of IK1 may restore pre-MI activation while not promoting arrhythmia.
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Affiliation(s)
- Damiano Fassina
- School of Biomedical Engineering and Imaging Sciences, King’s College London, London, United Kingdom
- National Heart and Lung Institute, Imperial College London, London, United Kingdom
| | - Caroline M. Costa
- School of Biomedical Engineering and Imaging Sciences, King’s College London, London, United Kingdom
| | - Stefano Longobardi
- School of Biomedical Engineering and Imaging Sciences, King’s College London, London, United Kingdom
| | - Elias Karabelas
- Institute of Mathematics & Scientific Computing, University of Graz, Graz, Austria
| | - Gernot Plank
- Gottfried Schatz Research Center (for Cell Signaling, Metabolism and Aging), Division Biophysics, Medical University of Graz, Graz, Austria
| | - Sian E. Harding
- National Heart and Lung Institute, Imperial College London, London, United Kingdom
| | - Steven A. Niederer
- School of Biomedical Engineering and Imaging Sciences, King’s College London, London, United Kingdom
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19
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Cooper BL, Posnack NG. Characteristics of Bisphenol Cardiotoxicity: Impaired Excitability, Contractility, and Relaxation. Cardiovasc Toxicol 2022; 22:273-280. [PMID: 35143014 PMCID: PMC9204785 DOI: 10.1007/s12012-022-09719-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Accepted: 01/04/2022] [Indexed: 12/14/2022]
Abstract
Bisphenol a (BPA) is a high production volume chemical that is frequently used to manufacture epoxy resins and polycarbonate plastics. BPA-containing products are now pervasive, and as a result, biomonitoring studies report widespread exposure in > 90% of adults, adolescents, and children. Both epidemiological and experimental studies have reported associations between BPA exposure and adverse cardiovascular health outcomes. With increasing concerns regarding BPA exposure, a few structurally similar bisphenol chemicals have been introduced as replacements, including bisphenol s (BPS) and bisphenol f (BPF). In accordance with the recently established "Key characteristics of cardiovascular toxicants", we reviewed the literature to highlight the immediate effects of bisphenol chemicals on (1) cardiac excitability, and (2) contractility and relaxation. BPA inhibits key cardiac ion channels, impairs cardiac excitability, and acts as a more potent inhibitor as compared to BPF and BPS. Through the inhibition of calcium current, some studies report that bisphenol chemicals can act as negative inotropic agents. Yet, others suggest that low dose exposures may increase contractility and precipitate triggered arrhythmias via the phosphorylation of key calcium handling proteins. Accordingly, we propose additional considerations for future work to comprehensively address the cardiac safety profile of BPA, as compared to replacement chemicals.
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Affiliation(s)
- Blake L. Cooper
- Children’s National Heart Institute, Children’s National Hospital, Washington, DC 20010, USA,Sheikh Zayed Institute for Pediatric Surgical Innovation, Children’s National Hospital, Washington, DC 20010, USA,Department of Pharmacology & Physiology, George Washington University, Washington, DC 20037, USA
| | - Nikki Gillum Posnack
- Children's National Heart Institute, Children's National Hospital, Washington, DC, 20010, USA. .,Sheikh Zayed Institute for Pediatric Surgical Innovation, Children's National Hospital, Washington, DC, 20010, USA. .,Department of Pediatrics, George Washington University, Washington, DC, 20037, USA. .,Department of Pharmacology & Physiology, George Washington University, Washington, DC, 20037, USA.
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20
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Sirish P, Diloretto DA, Thai PN, Chiamvimonvat N. The Critical Roles of Proteostasis and Endoplasmic Reticulum Stress in Atrial Fibrillation. Front Physiol 2022; 12:793171. [PMID: 35058801 PMCID: PMC8764384 DOI: 10.3389/fphys.2021.793171] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Accepted: 12/08/2021] [Indexed: 12/19/2022] Open
Abstract
Atrial fibrillation (AF) remains the most common arrhythmia seen clinically. The incidence of AF is increasing due to the aging population. AF is associated with a significant increase in morbidity and mortality, yet current treatment paradigms have proven largely inadequate. Therefore, there is an urgent need to develop new effective therapeutic strategies for AF. The endoplasmic reticulum (ER) in the heart plays critical roles in the regulation of excitation-contraction coupling and cardiac function. Perturbation in the ER homeostasis due to intrinsic and extrinsic factors, such as inflammation, oxidative stress, and ischemia, leads to ER stress that has been linked to multiple conditions including diabetes mellitus, neurodegeneration, cancer, heart disease, and cardiac arrhythmias. Recent studies have documented the critical roles of ER stress in the pathophysiological basis of AF. Using an animal model of chronic pressure overload, we demonstrate a significant increase in ER stress in atrial tissues. Moreover, we demonstrate that treatment with a small molecule inhibitor to inhibit the soluble epoxide hydrolase enzyme in the arachidonic acid metabolism significantly reduces ER stress as well as atrial electrical and structural remodeling. The current review article will attempt to provide a perspective on our recent understandings and current knowledge gaps on the critical roles of proteostasis and ER stress in AF progression.
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Affiliation(s)
- Padmini Sirish
- Division of Cardiovascular Medicine, Department of Internal Medicine, University of California, Davis, Davis, CA, United States.,Department of Veterans Affairs, Northern California Health Care System, Mather, CA, United States
| | - Daphne A Diloretto
- Division of Cardiovascular Medicine, Department of Internal Medicine, University of California, Davis, Davis, CA, United States
| | - Phung N Thai
- Division of Cardiovascular Medicine, Department of Internal Medicine, University of California, Davis, Davis, CA, United States.,Department of Veterans Affairs, Northern California Health Care System, Mather, CA, United States
| | - Nipavan Chiamvimonvat
- Division of Cardiovascular Medicine, Department of Internal Medicine, University of California, Davis, Davis, CA, United States.,Department of Veterans Affairs, Northern California Health Care System, Mather, CA, United States.,Department of Pharmacology, University of California, Davis, Davis, CA, United States
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21
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Morotti S, Liu C, Hegyi B, Ni H, Fogli Iseppe A, Wang L, Pritoni M, Ripplinger CM, Bers DM, Edwards AG, Grandi E. Quantitative cross-species translators of cardiac myocyte electrophysiology: Model training, experimental validation, and applications. SCIENCE ADVANCES 2021; 7:eabg0927. [PMID: 34788089 PMCID: PMC8598003 DOI: 10.1126/sciadv.abg0927] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Accepted: 09/28/2021] [Indexed: 05/13/2023]
Abstract
Animal experimentation is key in the evaluation of cardiac efficacy and safety of novel therapeutic compounds. However, interspecies differences in the mechanisms regulating excitation-contraction coupling can limit the translation of experimental findings from animal models to human physiology and undermine the assessment of drugs’ efficacy and safety. Here, we built a suite of translators for quantitatively mapping electrophysiological responses in ventricular myocytes across species. We trained these statistical operators using a broad dataset obtained by simulating populations of our biophysically detailed computational models of action potential and Ca2+ transient in mouse, rabbit, and human. We then tested our translators against experimental data describing the response to stimuli, such as ion channel block, change in beating rate, and β-adrenergic challenge. We demonstrate that this approach is well suited to predicting the effects of perturbations across different species or experimental conditions and suggest its integration into mechanistic studies and drug development pipelines.
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Affiliation(s)
- Stefano Morotti
- Department of Pharmacology, University of California Davis, Davis, CA 95616, USA
| | - Caroline Liu
- Department of Pharmacology, University of California Davis, Davis, CA 95616, USA
| | - Bence Hegyi
- Department of Pharmacology, University of California Davis, Davis, CA 95616, USA
| | - Haibo Ni
- Department of Pharmacology, University of California Davis, Davis, CA 95616, USA
| | - Alex Fogli Iseppe
- Department of Pharmacology, University of California Davis, Davis, CA 95616, USA
| | - Lianguo Wang
- Department of Pharmacology, University of California Davis, Davis, CA 95616, USA
| | - Marco Pritoni
- Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | | | - Donald M. Bers
- Department of Pharmacology, University of California Davis, Davis, CA 95616, USA
| | - Andrew G. Edwards
- Department of Pharmacology, University of California Davis, Davis, CA 95616, USA
| | - Eleonora Grandi
- Department of Pharmacology, University of California Davis, Davis, CA 95616, USA
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22
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Cooper BL, Gloschat C, Swift LM, Prudencio T, McCullough D, Jaimes R, Posnack NG. KairoSight: Open-Source Software for the Analysis of Cardiac Optical Data Collected From Multiple Species. Front Physiol 2021; 12:752940. [PMID: 34777017 PMCID: PMC8586513 DOI: 10.3389/fphys.2021.752940] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Accepted: 09/27/2021] [Indexed: 01/09/2023] Open
Abstract
Cardiac optical mapping, also known as optocardiography, employs parameter-sensitive fluorescence dye(s) to image cardiac tissue and resolve the electrical and calcium oscillations that underly cardiac function. This technique is increasingly being used in conjunction with, or even as a replacement for, traditional electrocardiography. Over the last several decades, optical mapping has matured into a “gold standard” for cardiac research applications, yet the analysis of optical signals can be challenging. Despite the refinement of software tools and algorithms, significant programming expertise is often required to analyze large optical data sets, and data analysis can be laborious and time-consuming. To address this challenge, we developed an accessible, open-source software script that is untethered from any subscription-based programming language. The described software, written in python, is aptly named “KairoSight” in reference to the Greek word for “opportune time” (Kairos) and the ability to “see” voltage and calcium signals acquired from cardiac tissue. To demonstrate analysis features and highlight species differences, we employed experimental datasets collected from mammalian hearts (Langendorff-perfused rat, guinea pig, and swine) dyed with RH237 (transmembrane voltage) and Rhod-2, AM (intracellular calcium), as well as human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CM) dyed with FluoVolt (membrane potential), and Fluo-4, AM (calcium indicator). We also demonstrate cardiac responsiveness to ryanodine (ryanodine receptor modulator) and isoproterenol (beta-adrenergic agonist) and highlight regional differences after an ablation injury. KairoSight can be employed by both basic and clinical scientists to analyze complex cardiac optical mapping datasets without requiring dedicated computer science expertise or proprietary software.
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Affiliation(s)
- Blake L Cooper
- Sheikh Zayed Institute for Pediatric Surgical Innovation, Children's National Hospital, Washington, DC, United States.,Children's National Heart Institute, Children's National Hospital, Washington, DC, United States.,Department of Pharmacology and Physiology, George Washington University, Washington, DC, United States
| | - Chris Gloschat
- Sheikh Zayed Institute for Pediatric Surgical Innovation, Children's National Hospital, Washington, DC, United States.,Children's National Heart Institute, Children's National Hospital, Washington, DC, United States
| | - Luther M Swift
- Sheikh Zayed Institute for Pediatric Surgical Innovation, Children's National Hospital, Washington, DC, United States.,Children's National Heart Institute, Children's National Hospital, Washington, DC, United States
| | - Tomas Prudencio
- Sheikh Zayed Institute for Pediatric Surgical Innovation, Children's National Hospital, Washington, DC, United States.,Children's National Heart Institute, Children's National Hospital, Washington, DC, United States
| | - Damon McCullough
- Sheikh Zayed Institute for Pediatric Surgical Innovation, Children's National Hospital, Washington, DC, United States.,Children's National Heart Institute, Children's National Hospital, Washington, DC, United States
| | - Rafael Jaimes
- Sheikh Zayed Institute for Pediatric Surgical Innovation, Children's National Hospital, Washington, DC, United States.,Children's National Heart Institute, Children's National Hospital, Washington, DC, United States
| | - Nikki G Posnack
- Sheikh Zayed Institute for Pediatric Surgical Innovation, Children's National Hospital, Washington, DC, United States.,Children's National Heart Institute, Children's National Hospital, Washington, DC, United States.,Department of Pharmacology and Physiology, George Washington University, Washington, DC, United States.,Department of Pediatrics, George Washington University, Washington, DC, United States
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23
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Sleiman Y, Lacampagne A, Meli AC. "Ryanopathies" and RyR2 dysfunctions: can we further decipher them using in vitro human disease models? Cell Death Dis 2021; 12:1041. [PMID: 34725342 PMCID: PMC8560800 DOI: 10.1038/s41419-021-04337-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Revised: 10/08/2021] [Accepted: 10/14/2021] [Indexed: 12/23/2022]
Abstract
The regulation of intracellular calcium (Ca2+) homeostasis is fundamental to maintain normal functions in many cell types. The ryanodine receptor (RyR), the largest intracellular calcium release channel located on the sarco/endoplasmic reticulum (SR/ER), plays a key role in the intracellular Ca2+ handling. Abnormal type 2 ryanodine receptor (RyR2) function, associated to mutations (ryanopathies) or pathological remodeling, has been reported, not only in cardiac diseases, but also in neuronal and pancreatic disorders. While animal models and in vitro studies provided valuable contributions to our knowledge on RyR2 dysfunctions, the human cell models derived from patients’ cells offer new hope for improving our understanding of human clinical diseases and enrich the development of great medical advances. We here discuss the current knowledge on RyR2 dysfunctions associated with mutations and post-translational remodeling. We then reviewed the novel human cellular technologies allowing the correlation of patient’s genome with their cellular environment and providing approaches for personalized RyR-targeted therapeutics.
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Affiliation(s)
- Yvonne Sleiman
- PhyMedExp, University of Montpellier, INSERM, CNRS, Montpellier, France
| | - Alain Lacampagne
- PhyMedExp, University of Montpellier, INSERM, CNRS, Montpellier, France
| | - Albano C Meli
- PhyMedExp, University of Montpellier, INSERM, CNRS, Montpellier, France.
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24
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Biasi N, Tognetti A. A computationally efficient dynamic model of human epicardial tissue. PLoS One 2021; 16:e0259066. [PMID: 34699557 PMCID: PMC8547700 DOI: 10.1371/journal.pone.0259066] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Accepted: 10/11/2021] [Indexed: 11/29/2022] Open
Abstract
We present a new phenomenological model of human ventricular epicardial cells and we test its reentry dynamics. The model is derived from the Rogers-McCulloch formulation of the FitzHugh-Nagumo equations and represents the total ionic current divided into three contributions corresponding to the excitatory, recovery and transient outward currents. Our model reproduces the main characteristics of human epicardial tissue, including action potential amplitude and morphology, upstroke velocity, and action potential duration and conduction velocity restitution curves. The reentry dynamics is stable, and the dominant period is about 270 ms, which is comparable to clinical values. The proposed model is the first phenomenological model able to accurately resemble human experimental data by using only 3 state variables and 17 parameters. Indeed, it is more computationally efficient than existing models (i.e., almost two times faster than the minimal ventricular model). Beyond the computational efficiency, the low number of parameters facilitates the process of fitting the model to the experimental data.
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Affiliation(s)
- Niccoló Biasi
- Department of Information Engineering, University of Pisa, Pisa, Italy
| | - Alessandro Tognetti
- Department of Information Engineering, University of Pisa, Pisa, Italy.,Research Centre "E. Piaggio", University of Pisa, Pisa, Italy
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25
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Wolfes J, Ellermann C, Bäumer S, Fehr M, Willy K, Wegner F, Leitz PR, Eckardt L, Frommeyer G. Experimental evidence for proarrhythmic effects of nonsteroidal anti-inflammatory drugs in a sensitive whole-heart model. Basic Clin Pharmacol Toxicol 2021; 130:103-109. [PMID: 34634184 DOI: 10.1111/bcpt.13671] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Revised: 09/21/2021] [Accepted: 10/05/2021] [Indexed: 11/28/2022]
Abstract
BACKGROUND Previous studies have raised serious concerns on cardiovascular safety of widely prescribed nonsteroidal anti-inflammatory drugs (NSAIDs). Therefore, the aim of this study was to characterize the electrophysiological effects of certain NSAIDs in an established whole heart model of proarrhythmia. METHODS AND RESULTS Thirty-eight hearts of New Zealand White rabbits were harvested and retrogradely perfused employing a Langendorff setup, and electrophysiology studies were performed to investigate action potential duration at 90% of repolarization (APD90 ), QT intervals, and effective refractory period (ERP). After generating baseline data, hearts were perfused with ibuprofen (Group 1, n = 12; 10 and 30 μM), indomethacin (Group 2, n = 13; 10 and 20 μM) and diclofenac (Group 3, n = 13; 10 and 20 μM), respectively, and the pacing protocols were repeated for each concentration. In all groups, perfusion with the NSAIDs resulted in a significant and reproducible shortening of APD90 and QT interval. In all groups, the arrhythmia susceptibility was significantly raised as occurrence of monomorphic ventricular tachycardia under programmed ventricular stimulation was significantly increased under perfusion with ibuprofen, indomethacin and diclofenac in all concentrations. CONCLUSION The perfusion with ibuprofen, indomethacin and diclofenac in commonly used doses raised the arrhythmia susceptibility in an established rabbit whole-heart model while APD shortening and shortened ERP seem to be crucial for arrhythmogenesis.
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Affiliation(s)
- Julian Wolfes
- Department of Cardiology II (Electrophysiology), University Hospital Münster, Münster, Germany
| | - Christian Ellermann
- Department of Cardiology II (Electrophysiology), University Hospital Münster, Münster, Germany
| | - Svenja Bäumer
- Klinik für Heimtiere, Reptilien und Vögel, University of Veterinary Medicine Hannover, Foundation, Hannover, Germany
| | - Michael Fehr
- Klinik für Heimtiere, Reptilien und Vögel, University of Veterinary Medicine Hannover, Foundation, Hannover, Germany
| | - Kevin Willy
- Department of Cardiology II (Electrophysiology), University Hospital Münster, Münster, Germany
| | - Felix Wegner
- Department of Cardiology II (Electrophysiology), University Hospital Münster, Münster, Germany
| | - Patrick R Leitz
- Department of Cardiology II (Electrophysiology), University Hospital Münster, Münster, Germany
| | - Lars Eckardt
- Department of Cardiology II (Electrophysiology), University Hospital Münster, Münster, Germany
| | - Gerrit Frommeyer
- Department of Cardiology II (Electrophysiology), University Hospital Münster, Münster, Germany
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26
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Setterberg IE, Le C, Frisk M, Li J, Louch WE. The Physiology and Pathophysiology of T-Tubules in the Heart. Front Physiol 2021; 12:718404. [PMID: 34566684 PMCID: PMC8458775 DOI: 10.3389/fphys.2021.718404] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Accepted: 07/07/2021] [Indexed: 12/18/2022] Open
Abstract
In cardiomyocytes, invaginations of the sarcolemmal membrane called t-tubules are critically important for triggering contraction by excitation-contraction (EC) coupling. These structures form functional junctions with the sarcoplasmic reticulum (SR), and thereby enable close contact between L-type Ca2+ channels (LTCCs) and Ryanodine Receptors (RyRs). This arrangement in turn ensures efficient triggering of Ca2+ release, and contraction. While new data indicate that t-tubules are capable of exhibiting compensatory remodeling, they are also widely reported to be structurally and functionally compromised during disease, resulting in disrupted Ca2+ homeostasis, impaired systolic and/or diastolic function, and arrhythmogenesis. This review summarizes these findings, while highlighting an emerging appreciation of the distinct roles of t-tubules in the pathophysiology of heart failure with reduced and preserved ejection fraction (HFrEF and HFpEF). In this context, we review current understanding of the processes underlying t-tubule growth, maintenance, and degradation, underscoring the involvement of a variety of regulatory proteins, including junctophilin-2 (JPH2), amphiphysin-2 (BIN1), caveolin-3 (Cav3), and newer candidate proteins. Upstream regulation of t-tubule structure/function by cardiac workload and specifically ventricular wall stress is also discussed, alongside perspectives for novel strategies which may therapeutically target these mechanisms.
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Affiliation(s)
- Ingunn E Setterberg
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway.,KG Jebsen Centre for Cardiac Research, University of Oslo, Oslo, Norway
| | - Christopher Le
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway.,KG Jebsen Centre for Cardiac Research, University of Oslo, Oslo, Norway
| | - Michael Frisk
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway.,KG Jebsen Centre for Cardiac Research, University of Oslo, Oslo, Norway
| | - Jia Li
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway.,KG Jebsen Centre for Cardiac Research, University of Oslo, Oslo, Norway
| | - William E Louch
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway.,KG Jebsen Centre for Cardiac Research, University of Oslo, Oslo, Norway
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27
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A comparative review on heart ion channels, action potentials and electrocardiogram in rodents and human: extrapolation of experimental insights to clinic. Lab Anim Res 2021; 37:25. [PMID: 34496976 PMCID: PMC8424989 DOI: 10.1186/s42826-021-00102-3] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Accepted: 08/26/2021] [Indexed: 11/10/2022] Open
Abstract
Electrocardiogram (ECG) is a non-invasive valuable diagnostic tool that is used in clinics for investigation and monitoring of heart electrical rhythm/conduction, ischemia/injury of heart, electrolyte disturbances and agents/drugs induced cardiac toxicity. Nowadays using animal models to study heart diseases such as electrical and mechanical disturbance is common. In addition, given to ethical consideration and availability, the use of small rodents has been a top priority for cardiovascular researchers. However, extrapolation of experimental findings from the lab to the clinic needs sufficient basic knowledge of similarities and differences between heart action potential and ECG of rodents and humans in normal and disease conditions. This review compares types of human action potentials, the dominant ion currents during action potential phases, alteration in ion channels activities in channelopathies-induced arrhythmias and the ECG appearance of mouse, rat, guinea pig, rabbit and human. Also, it briefly discusses the responsiveness and alterations in ECG following some interventions such as cardiac injury and arrhythmia induction. Overall, it provides a roadmap for researchers in selecting the best animal model/species whose studies results can be translated into clinical practice. In addition, this study will also be useful to biologists, physiologists, pharmacologists, veterinarians and physicians working in the fields of comparative physiology, pharmacology, toxicology and diseases.
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28
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Uzelac I, Iravanian S, Cherry EM, Fenton FH. Not all Long-QTs Are The Same, Proarrhytmic Quantification with Action Potential Triangulation and Alternans. COMPUTING IN CARDIOLOGY 2021; 48:10.23919/cinc53138.2021.9662721. [PMID: 35754519 PMCID: PMC9228587 DOI: 10.23919/cinc53138.2021.9662721] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Long-QT is commonly associated with an increased risk of polymorphic ventricular tachycardia from drug therapy. However, not all drugs prolonging QT interval are proarrhythmic. This study aimed to characterize cellular and tissue mechanisms under which QT-interval prolonging drugs and their combination are proarrhythmic, examining arrhythmia susceptibility due to action potential (AP) triangulation and spatial dispersion of action potential duration (APD). Additionally, we aimed to elucidate that Torsades de Pointe (TdP) associated with long-QT are not necessarily caused by early-after-depolarization (EADs) but are related to the presence of AP alternans in both time and space. Isolated Guinea Pig hearts were Langendorff perfused, and optical mapping was done with a voltage dye-sensitive dye. Two commonly used drugs at the beginning of the COVID-19 pandemic, hydroxychloroquine (HCQ) and Azithromycin (AZM), were added to study the effects of QT interval prolongation. Alternans in time and space were characterized by performing restitution pacing protocols. Comparing APs, HCQ prolongs APD during phase-III repolarization, resulting in a higher triangulation ratio than AZM alone or AZM combined with HCQ. Lower triangulation ratios with AZM are associated with phase-II prolongation, lower arrhythmia, and lower incidence of spatially discordant alternans.
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Affiliation(s)
- Ilija Uzelac
- School of Physics, Georgia Tech, Atlanta, GA, USA
| | | | - Elizabeth M Cherry
- School of Computational Science and Engineering, Georgia Institute of Technology, Atlanta, GA, USA
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29
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Lind L, Araujo JA, Barchowsky A, Belcher S, Berridge BR, Chiamvimonvat N, Chiu WA, Cogliano VJ, Elmore S, Farraj AK, Gomes AV, McHale CM, Meyer-Tamaki KB, Posnack NG, Vargas HM, Yang X, Zeise L, Zhou C, Smith MT. Key Characteristics of Cardiovascular Toxicants. ENVIRONMENTAL HEALTH PERSPECTIVES 2021; 129:95001. [PMID: 34558968 PMCID: PMC8462506 DOI: 10.1289/ehp9321] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
BACKGROUND The concept of chemical agents having properties that confer potential hazard called key characteristics (KCs) was first developed to identify carcinogenic hazards. Identification of KCs of cardiovascular (CV) toxicants could facilitate the systematic assessment of CV hazards and understanding of assay and data gaps associated with current approaches. OBJECTIVES We sought to develop a consensus-based synthesis of scientific evidence on the KCs of chemical and nonchemical agents known to cause CV toxicity along with methods to measure them. METHODS An expert working group was convened to discuss mechanisms associated with CV toxicity. RESULTS The group identified 12 KCs of CV toxicants, defined as exogenous agents that adversely interfere with function of the CV system. The KCs were organized into those primarily affecting cardiac tissue (numbers 1-4 below), the vascular system (5-7), or both (8-12), as follows: 1) impairs regulation of cardiac excitability, 2) impairs cardiac contractility and relaxation, 3) induces cardiomyocyte injury and death, 4) induces proliferation of valve stroma, 5) impacts endothelial and vascular function, 6) alters hemostasis, 7) causes dyslipidemia, 8) impairs mitochondrial function, 9) modifies autonomic nervous system activity, 10) induces oxidative stress, 11) causes inflammation, and 12) alters hormone signaling. DISCUSSION These 12 KCs can be used to help identify pharmaceuticals and environmental pollutants as CV toxicants, as well as to better understand the mechanistic underpinnings of their toxicity. For example, evidence exists that fine particulate matter [PM ≤2.5μm in aerodynamic diameter (PM2.5)] air pollution, arsenic, anthracycline drugs, and other exogenous chemicals possess one or more of the described KCs. In conclusion, the KCs could be used to identify potential CV toxicants and to define a set of test methods to evaluate CV toxicity in a more comprehensive and standardized manner than current approaches. https://doi.org/10.1289/EHP9321.
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Affiliation(s)
- Lars Lind
- Department of Medical Sciences, Clinical Epidemiology, University of Uppsala, Sweden
| | - Jesus A. Araujo
- Division of Cardiology, David Geffen School of Medicine at University of California Los Angeles (UCLA), UCLA, Los Angeles, California, USA
- Department of Environmental Health Sciences, Fielding School of Public Health and Molecular Biology Institute, UCLA, Los Angeles, California, USA
| | - Aaron Barchowsky
- Department of Environmental and Occupational Health, Graduate School of Public Health, University of Pittsburgh, Pennsylvania, USA
| | - Scott Belcher
- Department of Biological Sciences, North Carolina State University, North Carolina, USA
| | - Brian R. Berridge
- Division of the National Toxicology Program, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, North Carolina, USA
| | - Nipavan Chiamvimonvat
- Department of Internal Medicine, University of California, Davis, Davis, California, USA
| | - Weihsueh A. Chiu
- College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, Texas, USA
| | - Vincent J. Cogliano
- Office of Environmental Health Hazard Assessment, California Environmental Protection Agency (EPA), Oakland, California, USA
| | - Sarah Elmore
- Office of Environmental Health Hazard Assessment, California Environmental Protection Agency (EPA), Oakland, California, USA
| | - Aimen K. Farraj
- Public Health and Integrated Toxicology Division, Center for Public Health and Environmental Assessment, U.S. EPA, Research Triangle Park, North Carolina, USA
| | - Aldrin V. Gomes
- Department of Neurobiology, Physiology and Behavior, College of Biological Sciences, University of California, Davis, Davis, California, USA
| | - Cliona M. McHale
- Division of Environmental Health Sciences, School of Public Health, University of California, Berkeley, Berkeley, California, USA
| | | | - Nikki Gillum Posnack
- Children’s National Heart Institute and the Sheikh Zayed Institute for Pediatric Surgical Innovation, Children’s National Hospital, Washington, DC, USA
| | - Hugo M. Vargas
- Translational Safety & Bioanalytical Sciences, Amgen, Inc., Thousand Oaks, California, USA
| | - Xi Yang
- Division of Pharmacology and Toxicology, Office of Cardiology, Hematology, Endocrinology, and Nephrology, Center for Drug Evaluation and Research, Food and Drug Administration, Silver Spring, Maryland, USA
| | - Lauren Zeise
- Office of Environmental Health Hazard Assessment, California Environmental Protection Agency (EPA), Oakland, California, USA
| | - Changcheng Zhou
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, Riverside, California, USA
| | - Martyn T. Smith
- Division of Environmental Health Sciences, School of Public Health, University of California, Berkeley, Berkeley, California, USA
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Prudencio TM, Swift LM, Guerrelli D, Cooper B, Reilly M, Ciccarelli N, Sheng J, Jaimes R, Posnack NG. Bisphenol S and bisphenol F are less disruptive to cardiac electrophysiology, as compared to bisphenol A. Toxicol Sci 2021; 183:214-226. [PMID: 34240201 DOI: 10.1093/toxsci/kfab083] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Bisphenol A (BPA) is a high-production volume chemical used to manufacture consumer and medical-grade plastic products. Due to its ubiquity, the general population can incur daily environmental exposure to BPA, while heightened exposure has been reported in intensive care patients and industrial workers. Due to health concerns, structural analogues are being explored as replacements for BPA. This study aimed to examine the direct effects of BPA on cardiac electrophysiology compared with recently developed alternatives, including BPS (bisphenol S) and BPF (bisphenol F). Whole-cell voltage-clamp recordings were performed on cell lines transfected to express the voltage-gated sodium channel (Nav1.5), L-type voltage-gated calcium channel (Cav1.2), or the rapidly activating delayed rectifier potassium channel (hERG). Cardiac electrophysiology parameters were measured using human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CM) and intact, whole rat heart preparations. BPA was the most potent inhibitor of fast/peak (INa-P) and late (INa-L) sodium channel (IC50= 55.3, 23.6 µM, respectively), L-type calcium channel (IC50= 30.8 µM) and hERG channel current (IC50= 127 µM). Inhibitory effects on L-type calcium channels were supported by microelectrode array recordings, which revealed a shortening of the extracellular field potential (akin to QT interval). BPA and BPF exposures slowed atrioventricular (AV) conduction and increased AV node refractoriness in isolated rat heart preparations, in a dose-dependent manner (BPA: +9.2% 0.001 µM, +95.7% 100 µM; BPF: +20.7% 100 µM). BPS did not alter any of the cardiac electrophysiology parameters tested. Results of this study demonstrate that BPA and BPF exert an immediate inhibitory effect on cardiac ion channels, while BPS is markedly less potent. Additional studies are necessary to fully elucidate the safety profile of bisphenol analogues on the heart.
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Affiliation(s)
- Tomas M Prudencio
- Sheikh Zayed Institute for Pediatric Surgical Innovation, Children's National Hospital, Washington, DC, USA.,Children's National Heart Institute, Children's National Hospital, Washington, DC, USA
| | - Luther M Swift
- Sheikh Zayed Institute for Pediatric Surgical Innovation, Children's National Hospital, Washington, DC, USA.,Children's National Heart Institute, Children's National Hospital, Washington, DC, USA
| | - Devon Guerrelli
- Sheikh Zayed Institute for Pediatric Surgical Innovation, Children's National Hospital, Washington, DC, USA.,Children's National Heart Institute, Children's National Hospital, Washington, DC, USA.,Department of Biomedical Engineering, George Washington University, Washington DC, USA
| | - Blake Cooper
- Sheikh Zayed Institute for Pediatric Surgical Innovation, Children's National Hospital, Washington, DC, USA.,Children's National Heart Institute, Children's National Hospital, Washington, DC, USA.,Department of Pharmacology & Physiology, George Washington University, Washington DC, USA
| | - Marissa Reilly
- Sheikh Zayed Institute for Pediatric Surgical Innovation, Children's National Hospital, Washington, DC, USA.,Children's National Heart Institute, Children's National Hospital, Washington, DC, USA
| | - Nina Ciccarelli
- Sheikh Zayed Institute for Pediatric Surgical Innovation, Children's National Hospital, Washington, DC, USA.,Children's National Heart Institute, Children's National Hospital, Washington, DC, USA
| | | | - Rafael Jaimes
- Sheikh Zayed Institute for Pediatric Surgical Innovation, Children's National Hospital, Washington, DC, USA.,Children's National Heart Institute, Children's National Hospital, Washington, DC, USA
| | - Nikki Gillum Posnack
- Sheikh Zayed Institute for Pediatric Surgical Innovation, Children's National Hospital, Washington, DC, USA.,Children's National Heart Institute, Children's National Hospital, Washington, DC, USA.,Department of Pharmacology & Physiology, George Washington University, Washington DC, USA.,Department of Pediatrics, George Washington University, Washington DC, USA
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31
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Palmer JA, Smith AM, Gryshkova V, Donley ELR, Valentin JP, Burrier RE. A Targeted Metabolomics-Based Assay Using Human Induced Pluripotent Stem Cell-Derived Cardiomyocytes Identifies Structural and Functional Cardiotoxicity Potential. Toxicol Sci 2021; 174:218-240. [PMID: 32040181 DOI: 10.1093/toxsci/kfaa015] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Implementing screening assays that identify functional and structural cardiotoxicity earlier in the drug development pipeline has the potential to improve safety and decrease the cost and time required to bring new drugs to market. In this study, a metabolic biomarker-based assay was developed that predicts the cardiotoxicity potential of a drug based on changes in the metabolism and viability of human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CM). Assay development and testing was conducted in 2 phases: (1) biomarker identification and (2) targeted assay development. In the first phase, metabolomic data from hiPSC-CM spent media following exposure to 66 drugs were used to identify biomarkers that identified both functional and structural cardiotoxicants. Four metabolites that represent different metabolic pathways (arachidonic acid, lactic acid, 2'-deoxycytidine, and thymidine) were identified as indicators of cardiotoxicity. In phase 2, a targeted, exposure-based biomarker assay was developed that measured these metabolites and hiPSC-CM viability across an 8-point concentration curve. Metabolite-specific predictive thresholds for identifying the cardiotoxicity potential of a drug were established and optimized for balanced accuracy or sensitivity. When predictive thresholds were optimized for balanced accuracy, the assay predicted the cardiotoxicity potential of 81 drugs with 86% balanced accuracy, 83% sensitivity, and 90% specificity. Alternatively, optimizing the thresholds for sensitivity yields a balanced accuracy of 85%, 90% sensitivity, and 79% specificity. This new hiPSC-CM-based assay provides a paradigm that can identify structural and functional cardiotoxic drugs that could be used in conjunction with other endpoints to provide a more comprehensive evaluation of a drug's cardiotoxicity potential.
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Affiliation(s)
| | - Alan M Smith
- Stemina Biomarker Discovery, Inc, Madison, Wisconsin
| | - Vitalina Gryshkova
- UCB Biopharma SPRL, Investigative Toxicology, Development Science, B-1420 Braine L'Alleud, Belgium
| | | | - Jean-Pierre Valentin
- UCB Biopharma SPRL, Investigative Toxicology, Development Science, B-1420 Braine L'Alleud, Belgium
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32
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Orini M, Taggart P, Bhuva A, Roberts N, Di Salvo C, Yates M, Badiani S, Van Duijvenboden S, Lloyd G, Smith A, Lambiase PD. Direct in vivo assessment of global and regional mechanoelectric feedback in the intact human heart. Heart Rhythm 2021; 18:1406-1413. [PMID: 33932588 PMCID: PMC8353585 DOI: 10.1016/j.hrthm.2021.04.026] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Revised: 04/23/2021] [Accepted: 04/23/2021] [Indexed: 02/06/2023]
Abstract
Background Inhomogeneity of ventricular contraction is associated with sudden cardiac death, but the underlying mechanisms are unclear. Alterations in cardiac contraction impact electrophysiological parameters through mechanoelectric feedback. This has been shown to promote arrhythmias in experimental studies, but its effect in the in vivo human heart is unclear. Objective The purpose of this study was to quantify the impact of regional myocardial deformation provoked by a sudden increase in ventricular loading (aortic occlusion) on human cardiac electrophysiology. Methods In 10 patients undergoing open heart cardiac surgery, left ventricular (LV) afterload was modified by transient aortic occlusion. Simultaneous assessment of whole-heart electrophysiology and LV deformation was performed using an epicardial sock (240 electrodes) and speckle-tracking transesophageal echocardiography. Parameters were matched to 6 American Heart Association LV model segments. The association between changes in regional myocardial segment length and activation-recovery interval (ARI; a conventional surrogate for action potential duration) was studied using mixed-effect models. Results Increased ventricular loading reduced longitudinal shortening (P = .01) and shortened ARI (P = .02), but changes were heterogeneous between cardiac segments. Increased regional longitudinal shortening was associated with ARI shortening (effect size 0.20 [0.01–0.38] ms/%; P = .04) and increased local ARI dispersion (effect size –0.13 [–0.23 to –0.03] ms/%; P = .04). At the whole organ level, increased mechanical dispersion translated into increased dispersion of repolarization (correlation coefficient r = 0.81; P = .01). Conclusion Mechanoelectric feedback can establish a potentially proarrhythmic substrate in the human heart and should be considered to advance our understanding and prevention of cardiac arrhythmias.
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Affiliation(s)
- Michele Orini
- Electrophysiology Department, Barts Heart Centre at St. Bartholomew's Hospital, London, United Kingdom; Institute of Cardiovascular Science, University College London, London, United Kingdom
| | - Peter Taggart
- Institute of Cardiovascular Science, University College London, London, United Kingdom.
| | - Anish Bhuva
- Electrophysiology Department, Barts Heart Centre at St. Bartholomew's Hospital, London, United Kingdom; Institute of Cardiovascular Science, University College London, London, United Kingdom
| | - Neil Roberts
- Electrophysiology Department, Barts Heart Centre at St. Bartholomew's Hospital, London, United Kingdom
| | - Carmelo Di Salvo
- Electrophysiology Department, Barts Heart Centre at St. Bartholomew's Hospital, London, United Kingdom
| | - Martin Yates
- Electrophysiology Department, Barts Heart Centre at St. Bartholomew's Hospital, London, United Kingdom
| | - Sveeta Badiani
- Electrophysiology Department, Barts Heart Centre at St. Bartholomew's Hospital, London, United Kingdom
| | | | - Guy Lloyd
- Electrophysiology Department, Barts Heart Centre at St. Bartholomew's Hospital, London, United Kingdom
| | - Andrew Smith
- Electrophysiology Department, Barts Heart Centre at St. Bartholomew's Hospital, London, United Kingdom
| | - Pier D Lambiase
- Electrophysiology Department, Barts Heart Centre at St. Bartholomew's Hospital, London, United Kingdom; Institute of Cardiovascular Science, University College London, London, United Kingdom
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33
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Tse G, Hao G, Lee S, Zhou J, Zhang Q, Du Y, Liu T, Cheng SH, Wong WT. Measures of repolarization variability predict ventricular arrhythmogenesis in heptanol-treated Langendorff-perfused mouse hearts. Curr Res Physiol 2021; 4:125-134. [PMID: 34746832 PMCID: PMC8562203 DOI: 10.1016/j.crphys.2021.04.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Revised: 04/07/2021] [Accepted: 04/12/2021] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Time-domain and non-linear methods can be used to quantify beat-to-beat repolarization variability but whether measures of repolarization variability can predict ventricular arrhythmogenesis in mice have never been explored. METHODS Left ventricular monophasic action potentials (MAPs) were recorded during constant right ventricular 8 Hz pacing in Langendorff-perfused mouse hearts, in the presence or absence of the gap junction and sodium channel inhibitor heptanol (0.1, 0.5, 1 or 2 mM). RESULTS Under control conditions, mean action potential duration (APD) was 39.4 ± 8.1 ms. Standard deviation (SD) of APDs was 0.3 ± 0.2 ms, coefficient of variation was 0.9 ± 0.8% and the root mean square (RMS) of successive differences in APDs was 0.15 ± 0.14 ms. Poincaré plots of APDn+1 against APDn revealed ellipsoid morphologies with a SD along the line-of-identity (SD2) to SD perpendicular to the line-of-identity (SD1) ratio of 4.6 ± 2.1. Approximate and sample entropy were 0.61 ± 0.12 and 0.76 ± 0.26, respectively. Detrended fluctuation analysis revealed short- and long-term fluctuation slopes of 1.49 ± 0.27 and 0.81 ± 0.36, respectively. Heptanol at 2 mM induced ventricular tachycardia in five out of six hearts. None of the above parameters were altered by heptanol during which reproducible electrical activity was observed (KW-ANOVA, P > 0.05). Contrastingly, SD2/SD1 decreased to 2.03 ± 0.41, approximate and sample entropy increased to 0.82 ± 0.12 and 1.45 ± 0.34, and short-term fluctuation slope decreased to 0.82 ± 0.19 during the 20-s period preceding spontaneous ventricular tachy-arrhythmias (n = 6, KW-ANOVA, P < 0.05). CONCLUSION Measures of repolarization variability, such as SD2/SD1, entropy, and fluctuation slope are altered preceding the occurrence of ventricular arrhythmogenesis in mouse hearts. Changes in these variables may allow detection of impending arrhythmias for early intervention.
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Affiliation(s)
- Gary Tse
- Tianjin Key Laboratory of Ionic-Molecular Function of Cardiovascular Disease, Department of Cardiology, Tianjin Institute of Cardiology, Second Hospital of Tianjin Medical University, Tianjin, 300211, China
- Cardiovascular Analytics Group, Laboratory of Cardiovascular Physiology, Hong Kong, China
| | - Guoliang Hao
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Sharen Lee
- Cardiovascular Analytics Group, Laboratory of Cardiovascular Physiology, Hong Kong, China
| | - Jiandong Zhou
- School of Data Science, City University of Hong Kong, Hong Kong, China
| | - Qingpeng Zhang
- School of Data Science, City University of Hong Kong, Hong Kong, China
| | - Yimei Du
- Research Center of Ion Channelopathy, Institute of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Tong Liu
- Tianjin Key Laboratory of Ionic-Molecular Function of Cardiovascular Disease, Department of Cardiology, Tianjin Institute of Cardiology, Second Hospital of Tianjin Medical University, Tianjin, 300211, China
| | - Shuk Han Cheng
- Department of Biomedical Sciences, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong, Hong Kong
| | - Wing Tak Wong
- School of Life Sciences, Chinese University of Hong Kong, Hong Kong, China
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34
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Human Induced Pluripotent Stem Cell-Derived Cardiomyocytes: The New Working Horse in Cardiovascular Pharmacology? J Cardiovasc Pharmacol 2021; 77:265-266. [PMID: 33433138 DOI: 10.1097/fjc.0000000000000981] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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35
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Bai J, Zhu Y, Lo A, Gao M, Lu Y, Zhao J, Zhang H. In Silico Assessment of Class I Antiarrhythmic Drug Effects on Pitx2-Induced Atrial Fibrillation: Insights from Populations of Electrophysiological Models of Human Atrial Cells and Tissues. Int J Mol Sci 2021; 22:1265. [PMID: 33514068 PMCID: PMC7866025 DOI: 10.3390/ijms22031265] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Revised: 01/17/2021] [Accepted: 01/18/2021] [Indexed: 02/07/2023] Open
Abstract
Electrical remodelling as a result of homeodomain transcription factor 2 (Pitx2)-dependent gene regulation was linked to atrial fibrillation (AF) and AF patients with single nucleotide polymorphisms at chromosome 4q25 responded favorably to class I antiarrhythmic drugs (AADs). The possible reasons behind this remain elusive. The purpose of this study was to assess the efficacy of the AADs disopyramide, quinidine, and propafenone on human atrial arrhythmias mediated by Pitx2-induced remodelling, from a single cell to the tissue level, using drug binding models with multi-channel pharmacology. Experimentally calibrated populations of human atrial action po-tential (AP) models in both sinus rhythm (SR) and Pitx2-induced AF conditions were constructed by using two distinct models to represent morphological subtypes of AP. Multi-channel pharmaco-logical effects of disopyramide, quinidine, and propafenone on ionic currents were considered. Simulated results showed that Pitx2-induced remodelling increased maximum upstroke velocity (dVdtmax), and decreased AP duration (APD), conduction velocity (CV), and wavelength (WL). At the concentrations tested in this study, these AADs decreased dVdtmax and CV and prolonged APD in the setting of Pitx2-induced AF. Our findings of alterations in WL indicated that disopyramide may be more effective against Pitx2-induced AF than propafenone and quinidine by prolonging WL.
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Affiliation(s)
- Jieyun Bai
- Department of Electronic Engineering, College of Information Science and Technology, Jinan University, Guangzhou 510632, China;
| | - Yijie Zhu
- Department of Electronic Engineering, College of Information Science and Technology, Jinan University, Guangzhou 510632, China;
| | - Andy Lo
- Auckland Bioengineering Institute, University of Auckland, Auckland 1010, New Zealand; (A.L.); (J.Z.)
| | - Meng Gao
- Department of Computer Science and Technology, College of Electrical Engineering and Information, Northeast Agricultural University, Harbin 150030, China
| | - Yaosheng Lu
- Department of Electronic Engineering, College of Information Science and Technology, Jinan University, Guangzhou 510632, China;
| | - Jichao Zhao
- Auckland Bioengineering Institute, University of Auckland, Auckland 1010, New Zealand; (A.L.); (J.Z.)
| | - Henggui Zhang
- Biological Physics Group, School of Physics and Astronomy, The University of Manchester, Manchester M13 9PL, UK;
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36
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Arrhythmia Mechanisms in Human Induced Pluripotent Stem Cell-Derived Cardiomyocytes. J Cardiovasc Pharmacol 2020; 77:300-316. [PMID: 33323698 DOI: 10.1097/fjc.0000000000000972] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Accepted: 12/08/2020] [Indexed: 12/30/2022]
Abstract
ABSTRACT Despite major efforts by clinicians and researchers, cardiac arrhythmia remains a leading cause of morbidity and mortality in the world. Experimental work has relied on combining high-throughput strategies with standard molecular and electrophysiological studies, which are, to a great extent, based on the use of animal models. Because this poses major challenges for translation, the progress in the development of novel antiarrhythmic agents and clinical care has been mostly disappointing. Recently, the advent of human induced pluripotent stem cell-derived cardiomyocytes has opened new avenues for both basic cardiac research and drug discovery; now, there is an unlimited source of cardiomyocytes of human origin, both from healthy individuals and patients with cardiac diseases. Understanding arrhythmic mechanisms is one of the main use cases of human induced pluripotent stem cell-derived cardiomyocytes, in addition to pharmacological cardiotoxicity and efficacy testing, in vitro disease modeling, developing patient-specific models and personalized drugs, and regenerative medicine. Here, we review the advances that the human induced pluripotent stem cell-derived-based modeling systems have brought so far regarding the understanding of both arrhythmogenic triggers and substrates, while also briefly speculating about the possibilities in the future.
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37
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Reilly M, Bruno CD, Prudencio TM, Ciccarelli N, Guerrelli D, Nair R, Ramadan M, Luban NLC, Posnack NG. Potential Consequences of the Red Blood Cell Storage Lesion on Cardiac Electrophysiology. J Am Heart Assoc 2020; 9:e017748. [PMID: 33086931 PMCID: PMC7763412 DOI: 10.1161/jaha.120.017748] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Accepted: 09/04/2020] [Indexed: 12/17/2022]
Abstract
Background The red blood cell (RBC) storage lesion is a series of morphological, functional, and metabolic changes that RBCs undergo following collection, processing, and refrigerated storage for clinical use. Since the biochemical attributes of the RBC unit shifts with time, transfusion of older blood products may contribute to cardiac complications, including hyperkalemia and cardiac arrest. We measured the direct effect of storage age on cardiac electrophysiology and compared it with hyperkalemia, a prominent biomarker of storage lesion severity. Methods and Results Donor RBCs were processed using standard blood-banking techniques. The supernatant was collected from RBC units, 7 to 50 days after donor collection, for evaluation using Langendorff-heart preparations (rat) or human induced pluripotent stem cell-derived cardiomyocytes. Cardiac parameters remained stable following exposure to "fresh" supernatant from red blood cell units (day 7: 5.8±0.2 mM K+), but older blood products (day 40: 9.3±0.3 mM K+) caused bradycardia (baseline: 279±5 versus day 40: 216±18 beats per minute), delayed sinus node recovery (baseline: 243±8 versus day 40: 354±23 ms), and increased the effective refractory period of the atrioventricular node (baseline: 77±2 versus day 40: 93±7 ms) and ventricle (baseline: 50±3 versus day 40: 98±10 ms) in perfused hearts. Beating rate was also slowed in human induced pluripotent stem cell-derived cardiomyocytes after exposure to older supernatant from red blood cell units (-75±9%, day 40 versus control). Similar effects on automaticity and electrical conduction were observed with hyperkalemia (10-12 mM K+). Conclusions This is the first study to demonstrate that "older" blood products directly impact cardiac electrophysiology, using experimental models. These effects are likely caused by biochemical alterations in the supernatant from red blood cell units that occur over time, including, but not limited to hyperkalemia. Patients receiving large volume and/or rapid transfusions may be sensitive to these effects.
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Affiliation(s)
- Marissa Reilly
- Sheikh Zayed Institute for Pediatric Surgical InnovationChildren’s National HospitalWashingtonDC
- Children’s National Heart InstituteChildren’s National HospitalWashingtonDC
| | - Chantal D. Bruno
- Sheikh Zayed Institute for Pediatric Surgical InnovationChildren’s National HospitalWashingtonDC
- Division of Critical Care MedicineChildren’s National HospitalWashingtonDC
| | - Tomas M. Prudencio
- Sheikh Zayed Institute for Pediatric Surgical InnovationChildren’s National HospitalWashingtonDC
- Children’s National Heart InstituteChildren’s National HospitalWashingtonDC
| | - Nina Ciccarelli
- Sheikh Zayed Institute for Pediatric Surgical InnovationChildren’s National HospitalWashingtonDC
- Children’s National Heart InstituteChildren’s National HospitalWashingtonDC
| | - Devon Guerrelli
- Sheikh Zayed Institute for Pediatric Surgical InnovationChildren’s National HospitalWashingtonDC
- Children’s National Heart InstituteChildren’s National HospitalWashingtonDC
| | - Raj Nair
- Sheikh Zayed Institute for Pediatric Surgical InnovationChildren’s National HospitalWashingtonDC
| | - Manelle Ramadan
- Sheikh Zayed Institute for Pediatric Surgical InnovationChildren’s National HospitalWashingtonDC
- Children’s National Heart InstituteChildren’s National HospitalWashingtonDC
| | - Naomi L. C. Luban
- Division of Hematology and Laboratory MedicineChildren’s National HospitalWashingtonDC
- Department of PediatricsGeorge Washington UniversitySchool of MedicineWashingtonDC
- Department of PathologyGeorge Washington UniversitySchool of MedicineWashingtonDC
| | - Nikki Gillum Posnack
- Sheikh Zayed Institute for Pediatric Surgical InnovationChildren’s National HospitalWashingtonDC
- Children’s National Heart InstituteChildren’s National HospitalWashingtonDC
- Department of PediatricsGeorge Washington UniversitySchool of MedicineWashingtonDC
- Department of Pharmacology & PhysiologyGeorge Washington UniversitySchool of MedicineWashingtonDC
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38
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Approaches for determining cardiac bidomain conductivity values: progress and challenges. Med Biol Eng Comput 2020; 58:2919-2935. [PMID: 33089458 DOI: 10.1007/s11517-020-02272-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Accepted: 09/17/2020] [Indexed: 10/23/2022]
Abstract
Modelling the electrical activity of the heart is an important tool for understanding electrical function in various diseases and conduction disorders. Clearly, for model results to be useful, it is necessary to have accurate inputs for the models, in particular the commonly used bidomain model. However, there are only three sets of four experimentally determined conductivity values for cardiac ventricular tissue and these are inconsistent, were measured around 40 years ago, often produce different results in simulations and do not fully represent the three-dimensional anisotropic nature of cardiac tissue. Despite efforts in the intervening years, difficulties associated with making the measurements and also determining the conductivities from the experimental data have not yet been overcome. In this review, we summarise what is known about the conductivity values, as well as progress to date in meeting the challenges associated with both the mathematical modelling and the experimental techniques. Graphical abstract Epicardial potential distributions, arising from a subendocardial ischaemic region, modelled using conductivity data from the indicated studies.
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39
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Orini M, Yanni J, Taggart P, Hanson B, Hayward M, Smith A, Zhang H, Colman M, Jones G, Jie X, Dobrzynski H, Boyett MR, Lambiase PD. Mechanistic insights from targeted molecular profiling of repolarization alternans in the intact human heart. Europace 2020; 21:981-989. [PMID: 30753421 PMCID: PMC6545501 DOI: 10.1093/europace/euz007] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Revised: 10/17/2018] [Accepted: 01/21/2019] [Indexed: 02/05/2023] Open
Abstract
AIMS Action potential duration (APD) alternans is an established precursor or arrhythmia and sudden cardiac death. Important differences in fundamental electrophysiological properties relevant to arrhythmia exist between experimental models and the diseased in vivo human heart. To investigate mechanisms of APD alternans using a novel approach combining intact heart and cellular cardiac electrophysiology in human in vivo. METHODS AND RESULTS We developed a novel approach combining intact heart electrophysiological mapping during cardiac surgery with rapid on-site data analysis to guide myocardial biopsies for laboratory analysis, thereby linking repolarization dynamics observed at the organ level with underlying ion channel expression. Alternans-susceptible and alternans-resistant regions were identified by an incremental pacing protocol. Biopsies from these sites (n = 13) demonstrated greater RNA expression in Calsequestrin (CSQN) and Ryanodine (RyR) and ion channels underlying IK1 and Ito at alternans-susceptible sites. Electrical restitution properties (n = 7) showed no difference between alternans-susceptible and resistant sites, whereas spatial gradients of repolarization were greater in alternans-susceptible than in alternans-resistant sites (P = 0.001). The degree of histological fibrosis between alternans-susceptible and resistant sites was equivalent. Mathematical modelling of these changes indicated that both CSQN and RyR up-regulation are key determinants of APD alternans. CONCLUSION Combined intact heart and cellular electrophysiology show that regions of myocardium in the in vivo human heart exhibiting APD alternans are associated with greater expression of CSQN and RyR and show no difference in restitution properties compared to non-alternans regions. In silico modelling identifies up-regulation and interaction of CSQN with RyR as a major mechanism underlying APD alternans.
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Affiliation(s)
- Michele Orini
- Institute of Cardiovascular Science, University College London, London, UK.,Department of Electrophysiology, Barts Heart Centre at St Bartholomew's Hospital, London, UK
| | - Joseph Yanni
- Division of Cardiovascular Science, University of Manchester, Manchester, UK
| | - Peter Taggart
- Institute of Cardiovascular Science, University College London, London, UK
| | - Ben Hanson
- Department of Mechanical Engineering, University College London, UK
| | - Martin Hayward
- Department of Cardiothoracic Surgery, The Heart Hospital, University College London Hospitals, London, UK
| | - Andrew Smith
- Department of Electrophysiology, Barts Heart Centre at St Bartholomew's Hospital, London, UK
| | - Henggui Zhang
- Division of Cardiovascular Science, University of Manchester, Manchester, UK.,School of Physics and Astronomy, University of Manchester, Manchester, UK
| | | | - Gareth Jones
- School of Physics and Astronomy, University of Manchester, Manchester, UK
| | - Xiao Jie
- Institute of Cardiovascular Science, University College London, London, UK
| | - Halina Dobrzynski
- Division of Cardiovascular Science, University of Manchester, Manchester, UK
| | - Mark R Boyett
- Division of Cardiovascular Science, University of Manchester, Manchester, UK
| | - Pier D Lambiase
- Institute of Cardiovascular Science, University College London, London, UK.,Department of Electrophysiology, Barts Heart Centre at St Bartholomew's Hospital, London, UK
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40
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Genovés P, Arias-Mutis ÓJ, Parra G, Such-Miquel L, Zarzoso M, Del Canto I, Soler C, Díaz A, Blanch E, Alberola A, Such L, Chorro FJ. Development and Long-Term Follow-Up of an Experimental Model of Myocardial Infarction in Rabbits. Animals (Basel) 2020; 10:ani10091576. [PMID: 32899601 PMCID: PMC7552163 DOI: 10.3390/ani10091576] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Revised: 08/21/2020] [Accepted: 09/01/2020] [Indexed: 11/16/2022] Open
Abstract
Simple Summary Ischemic heart disease is one of the leading causes of death. A series of processes occur during acute myocardial infarction that contribute to the development of ventricular dysfunction, with subsequent heart failure and ventricular arrhythmias, which account for most episodes of sudden cardiac death in these patients. These complications are associated with the adverse cardiac remodeling that occurs during the healing process following an acute episode. The remodeling causes the appearance of a substrate that can trigger life-threatening arrhythmias, such as tachycardia and/or ventricular fibrillation. The development of experimental models for analyzing the basic mechanisms involved in the pathophysiology of myocardial infarction enables the study of different therapeutic approaches aimed at improving the patient´s prognosis. The present study describes the methodology and the results obtained in a 5-week chronic infarction (one hour followed by reperfusion) in a rabbit model. The viability of the model, the care provided, the characteristics and extent of the lesions, the inducibility of arrhythmias, and the reproducibility of the methods and results have been analyzed. Abstract A chronic model of acute myocardial infarction was developed to study the mechanisms involved in adverse postinfarction ventricular remodeling. In an acute myocardial infarction (AMI), the left circumflex coronary artery of New Zealand White rabbits (n = 9) was occluded by ligature for 1 h, followed by reperfusion. A specific care protocol was applied before, during, and after the intervention, and the results were compared with those of a sham operated group (n = 7). After 5 weeks, programmed stimulation and high-resolution mapping were performed on isolated and perfused hearts using the Langendorff technique. The infarct size determined by 2,3,5-triphenyltetrazolium chloride inside of the area at risk (thioflavin-S) was then determined. The area at risk was similar in both groups (54.33% (experimental infarct group) vs. 58.59% (sham group), ns). The infarct size was 73.16% as a percentage of the risk area. The experimental infarct group had a higher inducibility of ventricular arrhythmias (100% vs. 43% in the sham group, p = 0.009). A reproducible chronic experimental model of myocardial infarction is presented in which the extent and characteristics of the lesions enable the study of the vulnerability to develop ventricular arrhythmias because of the remodeling process that occurs during cardiac tissue repair.
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Affiliation(s)
- Patricia Genovés
- INCLIVA, Institute of Health Research, 46010 Valencia, Spain; (P.G.); (Ó.J.A.-M.); (G.P.); (I.D.C.)
- Department of Physiology, Universitat de València, 46010 Valencia, Spain; (C.S.); (A.A.); (L.S.)
| | - Óscar J. Arias-Mutis
- INCLIVA, Institute of Health Research, 46010 Valencia, Spain; (P.G.); (Ó.J.A.-M.); (G.P.); (I.D.C.)
- Department of Physiology, Universitat de València, 46010 Valencia, Spain; (C.S.); (A.A.); (L.S.)
| | - Germán Parra
- INCLIVA, Institute of Health Research, 46010 Valencia, Spain; (P.G.); (Ó.J.A.-M.); (G.P.); (I.D.C.)
- Department of Physiology, Universitat de València, 46010 Valencia, Spain; (C.S.); (A.A.); (L.S.)
| | - Luis Such-Miquel
- Department of Physiotherapy, Universitat de València, 46010 Valencia, Spain; (L.S.-M.); (M.Z.)
- CIBERCV, Carlos III Health Institute, 28029 Madrid, Spain
| | - Manuel Zarzoso
- Department of Physiotherapy, Universitat de València, 46010 Valencia, Spain; (L.S.-M.); (M.Z.)
| | - Irene Del Canto
- INCLIVA, Institute of Health Research, 46010 Valencia, Spain; (P.G.); (Ó.J.A.-M.); (G.P.); (I.D.C.)
- CIBERCV, Carlos III Health Institute, 28029 Madrid, Spain
- Electronic Engineering Department, Universitat Politècnica de València, 46022 Valencia, Spain
| | - Carlos Soler
- Department of Physiology, Universitat de València, 46010 Valencia, Spain; (C.S.); (A.A.); (L.S.)
| | - Ana Díaz
- UCIM, Universitat de València, 46010 Valencia, Spain; (A.D.); (E.B.)
| | - Eva Blanch
- UCIM, Universitat de València, 46010 Valencia, Spain; (A.D.); (E.B.)
| | - Antonio Alberola
- Department of Physiology, Universitat de València, 46010 Valencia, Spain; (C.S.); (A.A.); (L.S.)
- CIBERCV, Carlos III Health Institute, 28029 Madrid, Spain
| | - Luis Such
- Department of Physiology, Universitat de València, 46010 Valencia, Spain; (C.S.); (A.A.); (L.S.)
- CIBERCV, Carlos III Health Institute, 28029 Madrid, Spain
| | - Francisco J. Chorro
- INCLIVA, Institute of Health Research, 46010 Valencia, Spain; (P.G.); (Ó.J.A.-M.); (G.P.); (I.D.C.)
- CIBERCV, Carlos III Health Institute, 28029 Madrid, Spain
- Cardiology Department, Hospital Clinico Universitario, Universitat de València, Avda. Blasco Ibañez 17, 46010 Valencia, Spain
- Correspondence:
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Robinson P, Sparrow AJ, Patel S, Malinowska M, Reilly SN, Zhang YH, Casadei B, Watkins H, Redwood C. Dilated cardiomyopathy mutations in thin-filament regulatory proteins reduce contractility, suppress systolic Ca 2+, and activate NFAT and Akt signaling. Am J Physiol Heart Circ Physiol 2020; 319:H306-H319. [PMID: 32618513 PMCID: PMC7473929 DOI: 10.1152/ajpheart.00272.2020] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Dilated cardiomyopathy (DCM) is clinically characterized by dilated ventricular cavities and reduced ejection fraction, leading to heart failure and increased thromboembolic risk. Mutations in thin-filament regulatory proteins can cause DCM and have been shown in vitro to reduce contractility and myofilament Ca2+-affinity. In this work we have studied the functional consequences of mutations in cardiac troponin T (R131W), cardiac troponin I (K36Q) and α-tropomyosin (E40K) using adenovirally transduced isolated guinea pig left ventricular cardiomyocytes. We find significantly reduced fractional shortening with reduced systolic Ca2+. Contraction and Ca2+ reuptake times were slowed, which contrast with some findings in murine models of myofilament Ca2+ desensitization. We also observe increased sarcoplasmic reticulum (SR) Ca2+ load and smaller fractional SR Ca2+ release. This corresponds to a reduction in SR Ca2+-ATPase activity and increase in sodium-calcium exchanger activity. We also observe dephosphorylation and nuclear translocation of the nuclear factor of activated T cells (NFAT), with concordant RAC-α-serine/threonine protein kinase (Akt) phosphorylation but no change to extracellular signal-regulated kinase activation in chronically paced cardiomyocytes expressing DCM mutations. These changes in Ca2+ handling and signaling are common to all three mutations, indicating an analogous pathway of disease pathogenesis in thin-filament sarcomeric DCM. Previous work has shown that changes to myofilament Ca2+ sensitivity caused by DCM mutations are qualitatively opposite from hypertrophic cardiomyopathy (HCM) mutations in the same genes. However, we find several common pathways such as increased relaxation times and NFAT activation that are also hallmarks of HCM. This suggests more complex intracellular signaling underpinning DCM, driven by the primary mutation.NEW & NOTEWORTHY Dilated cardiomyopathy (DCM) is a frequently occurring cardiac disorder with a degree of genetic inheritance. We have found that DCM mutations in proteins that regulate the contractile machinery cause alterations to contraction, calcium-handling, and some new signaling pathways that provide stimuli for disease development. We have used guinea pig cells that recapitulate human calcium-handling and introduced the mutations using adenovirus gene transduction to look at the initial triggers of disease before remodeling.
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Affiliation(s)
- Paul Robinson
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom
- British Heart Foundation, Centre of Research Excellence, University of Oxford, Oxford, United Kingdom
| | - Alexander J Sparrow
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom
- British Heart Foundation, Centre of Research Excellence, University of Oxford, Oxford, United Kingdom
| | - Suketu Patel
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom
- British Heart Foundation, Centre of Research Excellence, University of Oxford, Oxford, United Kingdom
| | - Marta Malinowska
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom
- British Heart Foundation, Centre of Research Excellence, University of Oxford, Oxford, United Kingdom
| | - Svetlana N Reilly
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom
- British Heart Foundation, Centre of Research Excellence, University of Oxford, Oxford, United Kingdom
| | - Yin-Hua Zhang
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom
- British Heart Foundation, Centre of Research Excellence, University of Oxford, Oxford, United Kingdom
| | - Barbara Casadei
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom
- British Heart Foundation, Centre of Research Excellence, University of Oxford, Oxford, United Kingdom
| | - Hugh Watkins
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom
- British Heart Foundation, Centre of Research Excellence, University of Oxford, Oxford, United Kingdom
| | - Charles Redwood
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom
- British Heart Foundation, Centre of Research Excellence, University of Oxford, Oxford, United Kingdom
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Computational translation of drug effects from animal experiments to human ventricular myocytes. Sci Rep 2020; 10:10537. [PMID: 32601303 PMCID: PMC7324560 DOI: 10.1038/s41598-020-66910-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Accepted: 05/26/2020] [Indexed: 12/20/2022] Open
Abstract
Using animal cells and tissues as precise measuring devices for developing new drugs presents a long-standing challenge for the pharmaceutical industry. Despite the very significant resources that continue to be dedicated to animal testing of new compounds, only qualitative results can be obtained. This often results in both false positives and false negatives. Here, we show how the effect of drugs applied to animal ventricular myocytes can be translated, quantitatively, to estimate a number of different effects of the same drug on human cardiomyocytes. We illustrate and validate our methodology by translating, from animal to human, the effect of dofetilide applied to dog cardiomyocytes, the effect of E-4031 applied to zebrafish cardiomyocytes, and, finally, the effect of sotalol applied to rabbit cardiomyocytes. In all cases, the accuracy of our quantitative estimates are demonstrated. Our computations reveal that, in principle, electrophysiological data from testing using animal ventricular myocytes, can give precise, quantitative estimates of the effect of new compounds on human cardiomyocytes.
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43
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Widatalla N, Kasahara Y, Kimura Y, Khandoker A. Model based estimation of QT intervals in non-invasive fetal ECG signals. PLoS One 2020; 15:e0232769. [PMID: 32392232 PMCID: PMC7213701 DOI: 10.1371/journal.pone.0232769] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Accepted: 04/21/2020] [Indexed: 11/18/2022] Open
Abstract
The end timing of T waves in fetal electrocardiogram (fECG) is important for the evaluation of ST and QT intervals which are vital markers to assess cardiac repolarization patterns. Monitoring malignant fetal arrhythmias in utero is fundamental to care in congenital heart anomalies preventing perinatal death. Currently, reliable detection of end of T waves is possible only by using fetal scalp ECG (fsECG) and fetal magnetocardiography (fMCG). fMCG is expensive and less accessible and fsECG is an invasive technique available only during intrapartum period. Another safer and affordable alternative is the non-invasive fECG (nfECG) which can provide similar assessment provided by fsECG and fMECG but with less accuracy (not beat by beat). Detection of T waves using nfECG is challenging because of their low amplitudes and high noise. In this study, a novel model-based method that estimates the end of T waves in nfECG signals is proposed. The repolarization phase has been modeled as the discharging phase of a capacitor. To test the model, fECG signals were collected from 58 pregnant women (age: (34 ± 6) years old) bearing normal and abnormal fetuses with gestational age (GA) 20-41 weeks. QT and QTc intervals have been calculated to test the level of agreement between the model-based and reference values (fsECG and Doppler Ultrasound (DUS) signals) in normal subjects. The results of the test showed high agreement between model-based and reference values (difference < 5%), which implies that the proposed model could be an alternative method to detect the end of T waves in nfECG signals.
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Affiliation(s)
- Namareq Widatalla
- Next Generation Biological Information Technology, Tohoku University Graduate School of Biomedical Engineering, Sendai, Japan
- * E-mail:
| | - Yoshiyuki Kasahara
- Next Generation Biological Information Technology, Tohoku University Graduate School of Biomedical Engineering, Sendai, Japan
- Advanced Interdisciplinary Biomedical Engineering, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Yoshitaka Kimura
- Next Generation Biological Information Technology, Tohoku University Graduate School of Biomedical Engineering, Sendai, Japan
- Advanced Interdisciplinary Biomedical Engineering, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Ahsan Khandoker
- Healthcare Engineering Innovation Center (HEIC), Department of Biomedical Engineering, Khalifa University, Abu Dhabi, UAE
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44
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Abstract
Experimental models of cardiac disease play a key role in understanding the pathophysiology of the disease and developing new therapies. The features of the experimental models should reflect the clinical phenotype, which can have a wide spectrum of underlying mechanisms. We review characteristics of commonly used experimental models of cardiac physiology and pathophysiology in all translational steps including in vitro, small animal, and large animal models. Understanding their characteristics and relevance to clinical disease is the key for successful translation to effective therapies.
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45
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Dietrichs ES, Tveita T, Myles R, Smith G. A novel ECG-biomarker for cardiac arrest during hypothermia. Scand J Trauma Resusc Emerg Med 2020; 28:27. [PMID: 32276599 PMCID: PMC7149849 DOI: 10.1186/s13049-020-00721-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Accepted: 04/01/2020] [Indexed: 02/06/2023] Open
Abstract
Background Treatment of arrhythmias evoked by accidental or therapeutic hypothermia and rewarming remains challenging. We aim to find an ECG-biomarker that can predict ventricular arrhythmias at temperatures occurring in therapeutic and accidental hypothermia. Main body Evaluation of ECG-data from accidental and therapeutic hypothermia patients and experimental data on ECG and ventricular fibrillation (VF) threshold in hypothermic New Zealand White Rabbits. VF threshold was measured in rabbit hearts cooled to moderate (31 °C) and severe (17 °C) hypothermia. QRS-interval divided by corrected QT-interval (QTc) was calculated at same temperatures. Clinical QRS/QTc data were obtained after a systematic literature review. Rabbit QRS/QTc values correlated with risk for VF (correlation coefficient: 0.97). Human QRS/QTc values from hypothermic patients, showed similar correlation with risk for ventricular fibrillation in the experimental data (correlation coefficient: 1.00). Conclusions These calculations indicate that QRS/QTc has potential as novel biomarker for predicting risk of hypothermia-induced cardiac arrest. Our findings apply both to victims of accidental hypothermia and to patients undergoing therapeutic hypothermia during surgery or after e.g. cardiac arrest.
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Affiliation(s)
- Erik Sveberg Dietrichs
- Experimental and Clinical Pharmacology Research Group, Department of Medical Biology, UiT, The Arctic University of Norway, 9037, Tromsø, Norway. .,Department of Clinical Pharmacology, Division of Diagnostic Services, University Hospital of North Norway, 9038, Tromsø, Norway.
| | - Torkjel Tveita
- Anesthesia and Critical Care Research Group, Department of Clinical Medicine, UiT, The Arctic University of Norway, 9037, Tromsø, Norway.,Division of Surgical Medicine and Intensive Care, University Hospital of North Norway, 9038, Tromsø, Norway
| | - Rachel Myles
- Institute of Cardiovascular & Medical Sciences, University of Glasgow, Glasgow, UK
| | - Godfrey Smith
- Institute of Cardiovascular & Medical Sciences, University of Glasgow, Glasgow, UK
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46
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Jæger KH, Charwat V, Charrez B, Finsberg H, Maleckar MM, Wall S, Healy KE, Tveito A. Improved Computational Identification of Drug Response Using Optical Measurements of Human Stem Cell Derived Cardiomyocytes in Microphysiological Systems. Front Pharmacol 2020; 10:1648. [PMID: 32116671 PMCID: PMC7029356 DOI: 10.3389/fphar.2019.01648] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Accepted: 12/16/2019] [Indexed: 11/13/2022] Open
Abstract
Cardiomyocytes derived from human induced pluripotent stem cells (hiPSC-CMs) hold great potential for drug screening applications. However, their usefulness is limited by the relative immaturity of the cells' electrophysiological properties as compared to native cardiomyocytes in the adult human heart. In this work, we extend and improve on methodology to address this limitation, building on previously introduced computational procedures which predict drug effects for adult cells based on changes in optical measurements of action potentials and Ca2+ transients made in stem cell derived cardiac microtissues. This methodology quantifies ion channel changes through the inversion of data into a mathematical model, and maps this response to an adult phenotype through the assumption of functional invariance of fundamental intracellular and membrane channels during maturation. Here, we utilize an updated action potential model to represent both hiPSC-CMs and adult cardiomyocytes, apply an IC50-based model of dose-dependent drug effects, and introduce a continuation-based optimization algorithm for analysis of dose escalation measurements using five drugs with known effects. The improved methodology can identify drug induced changes more efficiently, and quantitate important metrics such as IC50 in line with published values. Consequently, the updated methodology is a step towards employing computational procedures to elucidate drug effects in adult cardiomyocytes for new drugs using stem cell-derived experimental tissues.
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Affiliation(s)
| | - Verena Charwat
- Department of Bioengineering, College of Engineering, University of California, Berkeley, CA, United States
| | - Bérénice Charrez
- Department of Bioengineering, College of Engineering, University of California, Berkeley, CA, United States
| | - Henrik Finsberg
- Department of Scientific Computing, Simula Research Laboratory, Oslo, Norway
| | - Mary M. Maleckar
- Department of Scientific Computing, Simula Research Laboratory, Oslo, Norway
| | - Samuel Wall
- Department of Scientific Computing, Simula Research Laboratory, Oslo, Norway
| | - Kevin E. Healy
- Department of Bioengineering, College of Engineering, University of California, Berkeley, CA, United States
- Department of Materials Science and Engineering, College of Engineering, University of California, Berkeley, CA, United States
| | - Aslak Tveito
- Department of Scientific Computing, Simula Research Laboratory, Oslo, Norway
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47
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Abi-Gerges N, Miller PE, Ghetti A. Human Heart Cardiomyocytes in Drug Discovery and Research: New Opportunities in Translational Sciences. Curr Pharm Biotechnol 2019; 21:787-806. [PMID: 31820682 DOI: 10.2174/1389201021666191210142023] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Revised: 10/14/2019] [Accepted: 10/28/2019] [Indexed: 12/28/2022]
Abstract
In preclinical drug development, accurate prediction of drug effects on the human heart is critically important, whether in the context of cardiovascular safety or for the purpose of modulating cardiac function to treat heart disease. Current strategies have significant limitations, whereby, cardiotoxic drugs can escape detection or potential life-saving therapies are abandoned due to false positive toxicity signals. Thus, new and more reliable translational approaches are urgently needed to help accelerate the rate of new therapy development. Renewed efforts in the recovery of human donor hearts for research and in cardiomyocyte isolation methods, are providing new opportunities for preclinical studies in adult primary cardiomyocytes. These cells exhibit the native physiological and pharmacological properties, overcoming the limitations presented by artificial cellular models, animal models and have great potential for providing an excellent tool for preclinical drug testing. Adult human primary cardiomyocytes have already shown utility in assessing drug-induced cardiotoxicity risk and helping in the identification of new treatments for cardiac diseases, such as heart failure and atrial fibrillation. Finally, strategies with actionable decision-making trees that rely on data derived from adult human primary cardiomyocytes will provide the holistic insights necessary to accurately predict human heart effects of drugs.
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Affiliation(s)
- Najah Abi-Gerges
- AnaBios Corporation, 3030 Bunker Hill St., Suite 312, San Diego, CA 92109, United States
| | - Paul E Miller
- AnaBios Corporation, 3030 Bunker Hill St., Suite 312, San Diego, CA 92109, United States
| | - Andre Ghetti
- AnaBios Corporation, 3030 Bunker Hill St., Suite 312, San Diego, CA 92109, United States
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48
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Timmermann V, Edwards AG, Wall ST, Sundnes J, McCulloch AD. Arrhythmogenic Current Generation by Myofilament-Triggered Ca 2+ Release and Sarcomere Heterogeneity. Biophys J 2019; 117:2471-2485. [PMID: 31810659 PMCID: PMC6990379 DOI: 10.1016/j.bpj.2019.11.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Revised: 11/04/2019] [Accepted: 11/05/2019] [Indexed: 01/05/2023] Open
Abstract
Heterogeneous mechanical dyskinesis has been implicated in many arrhythmogenic phenotypes. Strain-dependent perturbations to cardiomyocyte electrophysiology may contribute to this arrhythmogenesis through processes referred to as mechanoelectric feedback. Although the role of stretch-activated ion currents has been investigated using computational models, experimental studies suggest that mechanical strain may also promote arrhythmia by facilitating calcium wave propagation. To investigate whether strain-dependent changes in calcium affinity to the myofilament may promote arrhythmogenic intracellular calcium waves, we modified a mathematical model of rabbit excitation-contraction coupling coupled to a model of myofilament activation and force development. In a one-dimensional compartmental analysis, we bidirectionally coupled 50 sarcomere models in series to model calcium diffusion and stress transfer between adjacent sarcomeres. These considerations enabled the model to capture 1) the effects of mechanical feedback on calcium homeostasis at the sarcomeric level and 2) the combined effects of mechanical and calcium heterogeneities at the cellular level. The results suggest that in conditions of calcium overload, the vulnerable window of stretch-release to trigger suprathreshold delayed afterdepolarizations can be affected by heterogeneity in sarcomere length. Furthermore, stretch and sarcomere heterogeneity may modulate the susceptibility threshold for delayed afterdepolarizations and the aftercontraction wave propagation velocity.
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Affiliation(s)
- Viviane Timmermann
- Simula Research Laboratory, Fornebu, Norway; University of Oslo, Oslo, Norway; University of California San Diego, La Jolla, California.
| | - Andrew G Edwards
- Simula Research Laboratory, Fornebu, Norway; University of Oslo, Oslo, Norway
| | | | - Joakim Sundnes
- University of Oslo, Oslo, Norway; University of California San Diego, La Jolla, California
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49
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Ellermann C, Coenen A, Niehues P, Leitz P, Kochhäuser S, Dechering DG, Fehr M, Eckardt L, Frommeyer G. Proarrhythmic Effect of Acetylcholine-Esterase Inhibitors Used in the Treatment of Alzheimer’s Disease: Benefit of Rivastigmine in an Experimental Whole-Heart Model. Cardiovasc Toxicol 2019; 20:168-175. [DOI: 10.1007/s12012-019-09543-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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50
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Wang L, Morotti S, Tapa S, Francis Stuart SD, Jiang Y, Wang Z, Myles RC, Brack KE, Ng GA, Bers DM, Grandi E, Ripplinger CM. Different paths, same destination: divergent action potential responses produce conserved cardiac fight-or-flight response in mouse and rabbit hearts. J Physiol 2019; 597:3867-3883. [PMID: 31215643 DOI: 10.1113/jp278016] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Accepted: 06/17/2019] [Indexed: 12/22/2022] Open
Abstract
KEY POINTS Cardiac electrophysiology and Ca2+ handling change rapidly during the fight-or-flight response to meet physiological demands. Despite dramatic differences in cardiac electrophysiology, the cardiac fight-or-flight response is highly conserved across species. In this study, we performed physiological sympathetic nerve stimulation (SNS) while optically mapping cardiac action potentials and intracellular Ca2+ transients in innervated mouse and rabbit hearts. Despite similar heart rate and Ca2+ handling responses between mouse and rabbit hearts, we found notable species differences in spatio-temporal repolarization dynamics during SNS. Species-specific computational models revealed that these electrophysiological differences allowed for enhanced Ca2+ handling (i.e. enhanced inotropy) in each species, suggesting that electrophysiological responses are fine-tuned across species to produce optimal cardiac fight-or-flight responses. ABSTRACT Sympathetic activation of the heart results in positive chronotropy and inotropy, which together rapidly increase cardiac output. The precise mechanisms that produce the electrophysiological and Ca2+ handling changes underlying chronotropic and inotropic responses have been studied in detail in isolated cardiac myocytes. However, few studies have examined the dynamic effects of physiological sympathetic nerve activation on cardiac action potentials (APs) and intracellular Ca2+ transients (CaTs) in the intact heart. Here, we performed bilateral sympathetic nerve stimulation (SNS) in fully innervated, Langendorff-perfused rabbit and mouse hearts. Dual optical mapping with voltage- and Ca2+ -sensitive dyes allowed for analysis of spatio-temporal AP and CaT dynamics. The rabbit heart responded to SNS with a monotonic increase in heart rate (HR), monotonic decreases in AP and CaT duration (APD, CaTD), and a monotonic increase in CaT amplitude. The mouse heart had similar HR and CaT responses; however, a pronounced biphasic APD response occurred, with initial prolongation (50.9 ± 5.1 ms at t = 0 s vs. 60.6 ± 4.1 ms at t = 15 s, P < 0.05) followed by shortening (46.5 ± 9.1 ms at t = 60 s, P = NS vs. t = 0). We determined the biphasic APD response in mouse was partly due to dynamic changes in HR during SNS and was exacerbated by β-adrenergic activation. Simulations with species-specific cardiac models revealed that transient APD prolongation in mouse allowed for greater and more rapid CaT responses, suggesting more rapid increases in contractility; conversely, the rabbit heart requires APD shortening to produce optimal inotropic responses. Thus, while the cardiac fight-or-flight response is highly conserved between species, the underlying mechanisms orchestrating these effects differ significantly.
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Affiliation(s)
- Lianguo Wang
- Department of Pharmacology, School of Medicine, University of California, Davis, USA
| | - Stefano Morotti
- Department of Pharmacology, School of Medicine, University of California, Davis, USA
| | - Srinivas Tapa
- Department of Pharmacology, School of Medicine, University of California, Davis, USA
| | | | - Yanyan Jiang
- Department of Pharmacology, School of Medicine, University of California, Davis, USA
| | - Zhen Wang
- Department of Pharmacology, School of Medicine, University of California, Davis, USA
| | - Rachel C Myles
- Institute of Cardiovascular & Medical Sciences, University of Glasgow, Glasgow, UK
| | - Kieran E Brack
- Department of Cardiovascular Sciences, University of Leicester, NIHR Leicester Biomedical Research Centre, Leicester, UK
| | - G André Ng
- Department of Cardiovascular Sciences, University of Leicester, NIHR Leicester Biomedical Research Centre, Leicester, UK
| | - Donald M Bers
- Department of Pharmacology, School of Medicine, University of California, Davis, USA
| | - Eleonora Grandi
- Department of Pharmacology, School of Medicine, University of California, Davis, USA
| | - Crystal M Ripplinger
- Department of Pharmacology, School of Medicine, University of California, Davis, USA
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