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Gokhan I, Blum TS, Campbell SG. Engineered heart tissue: Design considerations and the state of the art. BIOPHYSICS REVIEWS 2024; 5:021308. [PMID: 38912258 PMCID: PMC11192576 DOI: 10.1063/5.0202724] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2024] [Accepted: 05/29/2024] [Indexed: 06/25/2024]
Abstract
Originally developed more than 20 years ago, engineered heart tissue (EHT) has become an important tool in cardiovascular research for applications such as disease modeling and drug screening. Innovations in biomaterials, stem cell biology, and bioengineering, among other fields, have enabled EHT technologies to recapitulate many aspects of cardiac physiology and pathophysiology. While initial EHT designs were inspired by the isolated-trabecula culture system, current designs encompass a variety of formats, each of which have unique strengths and limitations. In this review, we describe the most common EHT formats, and then systematically evaluate each aspect of their design, emphasizing the rational selection of components for each application.
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Affiliation(s)
| | - Thomas S. Blum
- Department of Biomedical Engineering, Yale University, New Haven, Connecticut 06511, USA
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Shen S, Sewanan LR, Shao S, Halder SS, Stankey P, Li X, Campbell SG. Physiological calcium combined with electrical pacing accelerates maturation of human engineered heart tissue. Stem Cell Reports 2022; 17:2037-2049. [PMID: 35931080 PMCID: PMC9481907 DOI: 10.1016/j.stemcr.2022.07.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 07/08/2022] [Accepted: 07/08/2022] [Indexed: 12/24/2022] Open
Abstract
Human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) have wide potential application in basic research, drug discovery, and regenerative medicine, but functional maturation remains challenging. Here, we present a method whereby maturation of hiPSC-CMs can be accelerated by simultaneous application of physiological Ca2+ and frequency-ramped electrical pacing in culture. This combination produces positive force-frequency behavior, physiological twitch kinetics, robust β-adrenergic response, improved Ca2+ handling, and cardiac troponin I expression within 25 days. This study provides insights into the role of Ca2+ in hiPSC-CM maturation and offers a scalable platform for translational and clinical research.
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Affiliation(s)
- Shi Shen
- Department of Biomedical Engineering, Yale University, 55 Prospect St. MEC 211, New Haven, CT 06511, USA
| | - Lorenzo R Sewanan
- Department of Medicine, Columbia University Irving Medical Center, New York, NY, USA
| | - Stephanie Shao
- Department of Biomedical Engineering, Yale University, 55 Prospect St. MEC 211, New Haven, CT 06511, USA
| | - Saiti S Halder
- Department of Biomedical Engineering, Yale University, 55 Prospect St. MEC 211, New Haven, CT 06511, USA
| | - Paul Stankey
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA, USA; John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
| | - Xia Li
- Department of Biomedical Engineering, Yale University, 55 Prospect St. MEC 211, New Haven, CT 06511, USA
| | - Stuart G Campbell
- Department of Biomedical Engineering, Yale University, 55 Prospect St. MEC 211, New Haven, CT 06511, USA; Department of Cellular and Molecular Physiology, Yale University, New Haven, CT, USA.
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Mashali MA, Saad NS, Canan BD, Elnakish MT, Milani-Nejad N, Chung JH, Schultz EJ, Kiduko SA, Huang AW, Hare AN, Peczkowski KK, Fazlollahi F, Martin BL, Murray JD, Campbell CM, Kilic A, Whitson BA, Mokadam NA, Mohler PJ, Janssen PML. Impact of etiology on force and kinetics of left ventricular end-stage failing human myocardium. J Mol Cell Cardiol 2021; 156:7-19. [PMID: 33766524 PMCID: PMC8217133 DOI: 10.1016/j.yjmcc.2021.03.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Revised: 03/18/2021] [Accepted: 03/18/2021] [Indexed: 12/16/2022]
Abstract
BACKGROUND Heart failure (HF) is associated with highly significant morbidity, mortality, and health care costs. Despite the significant advances in therapies and prevention, HF remains associated with poor clinical outcomes. Understanding the contractile force and kinetic changes at the level of cardiac muscle during end-stage HF in consideration of underlying etiology would be beneficial in developing targeted therapies that can help improve cardiac performance. OBJECTIVE Investigate the impact of the primary etiology of HF (ischemic or non-ischemic) on left ventricular (LV) human myocardium force and kinetics of contraction and relaxation under near-physiological conditions. METHODS AND RESULTS Contractile and kinetic parameters were assessed in LV intact trabeculae isolated from control non-failing (NF; n = 58) and end-stage failing ischemic (FI; n = 16) and non-ischemic (FNI; n = 38) human myocardium under baseline conditions, length-dependent activation, frequency-dependent activation, and response to the β-adrenergic stimulation. At baseline, there were no significant differences in contractile force between the three groups; however, kinetics were impaired in failing myocardium with significant slowing down of relaxation kinetics in FNI compared to NF myocardium. Length-dependent activation was preserved and virtually identical in all groups. Frequency-dependent activation was clearly seen in NF myocardium (positive force frequency relationship [FFR]), while significantly impaired in both FI and FNI myocardium (negative FFR). Likewise, β-adrenergic regulation of contraction was significantly impaired in both HF groups. CONCLUSIONS End-stage failing myocardium exhibited impaired kinetics under baseline conditions as well as with the three contractile regulatory mechanisms. The pattern of these kinetic impairments in relation to NF myocardium was mainly impacted by etiology with a marked slowing down of kinetics in FNI myocardium. These findings suggest that not only force development, but also kinetics should be considered as a therapeutic target for improving cardiac performance and thus treatment of HF.
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Affiliation(s)
- Mohammed A Mashali
- Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, United States; Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, United States; Department of Surgery, Faculty of Veterinary Medicine, Damanhour University, Damanhour, Egypt
| | - Nancy S Saad
- Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, United States; Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, United States; Department of Pharmacology and Toxicology, Faculty of Pharmacy, Helwan University, Cairo, Egypt
| | - Benjamin D Canan
- Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, United States; Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, United States
| | - Mohammad T Elnakish
- Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, United States; Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, United States; Department of Pharmacology and Toxicology, Faculty of Pharmacy, Helwan University, Cairo, Egypt
| | - Nima Milani-Nejad
- Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, United States; Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, United States
| | - Jae-Hoon Chung
- Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, United States; Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, United States
| | - Eric J Schultz
- Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, United States; Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, United States
| | - Salome A Kiduko
- Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, United States; Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, United States
| | - Amanda W Huang
- Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, United States; Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, United States
| | - Austin N Hare
- Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, United States; Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, United States
| | - Kyra K Peczkowski
- Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, United States; Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, United States
| | - Farbod Fazlollahi
- Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, United States; Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, United States
| | - Brit L Martin
- Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, United States; Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, United States
| | - Jason D Murray
- Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, United States; Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, United States
| | - Courtney M Campbell
- Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, United States; Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, United States; Department of Internal Medicine, College of Medicine, The Ohio State University, Columbus, OH, United States
| | - Ahmet Kilic
- Division of Cardiac Surgery, College of Medicine, The Ohio State University, Columbus, OH, United States
| | - Bryan A Whitson
- Division of Cardiac Surgery, College of Medicine, The Ohio State University, Columbus, OH, United States
| | - Nahush A Mokadam
- Division of Cardiac Surgery, College of Medicine, The Ohio State University, Columbus, OH, United States
| | - Peter J Mohler
- Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, United States; Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, United States; Department of Internal Medicine, College of Medicine, The Ohio State University, Columbus, OH, United States
| | - Paul M L Janssen
- Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, United States; Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, United States; Department of Internal Medicine, College of Medicine, The Ohio State University, Columbus, OH, United States.
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Antigny F, Mercier O, Humbert M, Sabourin J. Excitation-contraction coupling and relaxation alteration in right ventricular remodelling caused by pulmonary arterial hypertension. Arch Cardiovasc Dis 2020; 113:70-84. [DOI: 10.1016/j.acvd.2019.10.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Revised: 10/18/2019] [Accepted: 10/23/2019] [Indexed: 02/09/2023]
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Janssen PML, Elnakish MT. Modeling heart failure in animal models for novel drug discovery and development. Expert Opin Drug Discov 2019; 14:355-363. [PMID: 30861352 DOI: 10.1080/17460441.2019.1582636] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
INTRODUCTION When investigating drugs that treat heart diseases, it is critical when choosing an animal model for the said model to produce data that is translatable to the human patient population, while keeping in mind the principles of reduction, refinement, and replacement of the animal model in the research. Areas covered: In this review, the authors focus on mammalian models developed to study the impact of drug treatments on human heart failure. Furthermore, the authors address human patient variability and animal model invariability as well as the considerations that need to be made regarding choice of species. Finally, the authors discuss some of the most common models for the two most prominent human heart failure etiologies; increased load on the heart and myocardial ischemia. Expert opinion: In the authors' opinion, the data generated by drug studies is often heavily impacted by the choice of species and the physiologically relevant conditions under which the data are collected. Approaches that use multiple models and are not restricted to small rodents but involve some verification on larger mammals or on human myocardium, are needed to advance drug discovery for the very large patient population that suffers from heart failure.
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Affiliation(s)
- Paul M L Janssen
- a Department of Physiology and Cell Biology , The Ohio State University Wexner Medical Center , Columbus, OH, USA.,b Dorothy M. Davis Heart and Lung Research Institute , The Ohio State University Wexner Medical Center , Columbus, OH, USA.,c Department of Internal Medicine , The Ohio State University Wexner Medical Center , Columbus, OH, USA
| | - Mohammad T Elnakish
- a Department of Physiology and Cell Biology , The Ohio State University Wexner Medical Center , Columbus, OH, USA.,b Dorothy M. Davis Heart and Lung Research Institute , The Ohio State University Wexner Medical Center , Columbus, OH, USA
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van der Velden J, Stienen GJM. Cardiac Disorders and Pathophysiology of Sarcomeric Proteins. Physiol Rev 2019; 99:381-426. [PMID: 30379622 DOI: 10.1152/physrev.00040.2017] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The sarcomeric proteins represent the structural building blocks of heart muscle, which are essential for contraction and relaxation. During recent years, it has become evident that posttranslational modifications of sarcomeric proteins, in particular phosphorylation, tune cardiac pump function at rest and during exercise. This delicate, orchestrated interaction is also influenced by mutations, predominantly in sarcomeric proteins, which cause hypertrophic or dilated cardiomyopathy. In this review, we follow a bottom-up approach starting from a description of the basic components of cardiac muscle at the molecular level up to the various forms of cardiac disorders at the organ level. An overview is given of sarcomere changes in acquired and inherited forms of cardiac disease and the underlying disease mechanisms with particular reference to human tissue. A distinction will be made between the primary defect and maladaptive/adaptive secondary changes. Techniques used to unravel functional consequences of disease-induced protein changes are described, and an overview of current and future treatments targeted at sarcomeric proteins is given. The current evidence presented suggests that sarcomeres not only form the basis of cardiac muscle function but also represent a therapeutic target to combat cardiac disease.
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Affiliation(s)
- Jolanda van der Velden
- Amsterdam UMC, Vrije Universiteit Amsterdam, Physiology, Amsterdam Cardiovascular Sciences, Amsterdam , The Netherlands ; and Department of Physiology, Kilimanjaro Christian Medical University College, Moshi, Tanzania
| | - Ger J M Stienen
- Amsterdam UMC, Vrije Universiteit Amsterdam, Physiology, Amsterdam Cardiovascular Sciences, Amsterdam , The Netherlands ; and Department of Physiology, Kilimanjaro Christian Medical University College, Moshi, Tanzania
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Janssen PML. Myocardial relaxation in human heart failure: Why sarcomere kinetics should be center-stage. Arch Biochem Biophys 2018; 661:145-148. [PMID: 30447209 DOI: 10.1016/j.abb.2018.11.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 10/12/2018] [Accepted: 11/13/2018] [Indexed: 12/19/2022]
Abstract
Myocardial relaxation is critical for the heart to allow for adequate filling of the ventricles prior to the next contraction. In human heart failure, impairment of myocardial relaxation is a major problem, and impacts most patients suffering from end-stage failure. Furthering our understanding of myocardial relaxation is critical in developing future treatment strategies. This review highlights processes involved in myocardial relaxation, as well as governing processes that modulate myocardial relaxation, with a focus on impairment of myocardium-level relaxation in human end-stage heart failure.
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Affiliation(s)
- Paul M L Janssen
- Department of Physiology and Cell Biology, The Ohio State University Wexner Medical Center, USA; Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, USA; Department of Internal Medicine, The Ohio State University Wexner Medical Center, USA.
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Monasky MM, Pappone C, Piccoli M, Ghiroldi A, Micaglio E, Anastasia L. Calcium in Brugada Syndrome: Questions for Future Research. Front Physiol 2018; 9:1088. [PMID: 30147658 PMCID: PMC6095984 DOI: 10.3389/fphys.2018.01088] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Accepted: 07/23/2018] [Indexed: 12/11/2022] Open
Abstract
The Brugada syndrome (BrS) is characterized by coved-type ST-segment elevation in the right precordial leads on the electrocardiogram (ECG) and increased risk of sudden cardiac death (SCD). While it is an inheritable disease, determining the true prevalence is a challenge, since patients may report no known family history of the syndrome, present with a normal spontaneous ECG pattern at the time of examination, and test negative for all known BrS-causative genes. In fact, SCD is often the first indication that a person is affected by the syndrome. Men are more likely to be symptomatic than women. Abnormal, low-voltage, fractionated electrograms have been found in the epicardium of the right ventricular outflow tract (RVOT). Ablation of this area abolishes the abnormal electrograms and helps to prevent arrhythmic recurrences. BrS patients are more likely to experience ventricular tachycardia/fibrillation (VT/VF) during fever or during an increase in vagal tone. Isoproterenol helps to reverse the ECG BrS phenotype. In this review, we discuss roles of calcium in various conditions that are relevant to BrS, such as changes in temperature, heart rate, and vagal tone, and the effects of gender and isoproterenol on calcium handling. Studies are warranted to further investigate these mechanisms in models of BrS.
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Affiliation(s)
| | - Carlo Pappone
- Arrhythmology Department, IRCCS Policlinico San Donato, Milan, Italy
| | - Marco Piccoli
- Stem Cells for Tissue Engineering Lab, IRCCS Policlinico San Donato, Milan, Italy
| | - Andrea Ghiroldi
- Stem Cells for Tissue Engineering Lab, IRCCS Policlinico San Donato, Milan, Italy
| | - Emanuele Micaglio
- Arrhythmology Department, IRCCS Policlinico San Donato, Milan, Italy
| | - Luigi Anastasia
- Stem Cells for Tissue Engineering Lab, IRCCS Policlinico San Donato, Milan, Italy.,Department of Biomedical Sciences for Health, University of Milan, Milan, Italy
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Etiology-dependent impairment of relaxation kinetics in right ventricular end-stage failing human myocardium. J Mol Cell Cardiol 2018; 121:81-93. [PMID: 29981798 DOI: 10.1016/j.yjmcc.2018.07.005] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Revised: 07/02/2018] [Accepted: 07/04/2018] [Indexed: 01/08/2023]
Abstract
BACKGROUND In patients with end-stage heart failure, the primary etiology often originates in the left ventricle, and eventually the contractile function of the right ventricle (RV) also becomes compromised. RV tissue-level deficits in contractile force and/or kinetics need quantification to understand involvement in ischemic and non-ischemic failing human myocardium. METHODS AND RESULTS The human population suffering from heart failure is diverse, requiring many subjects to be studied in order to perform an adequately powered statistical analysis. From 2009-present we assessed live tissue-level contractile force and kinetics in isolated myocardial RV trabeculae from 44 non-failing and 41 failing human hearts. At 1 Hz stimulation rate (in vivo resting state) the developed active force was not different in non-failing compared to failing ischemic nor non-ischemic failing trabeculae. In sharp contrast, the kinetics of relaxation were significantly impacted by disease, with 50% relaxation time being significantly shorter in non-failing vs. non-ischemic failing, while the latter was still significantly shorter than ischemic failing. Gender did not significantly impact kinetics. Length-dependent activation was not impacted. Although baseline force was not impacted, contractile reserve was critically blunted. The force-frequency relation was positive in non-failing myocardium, but negative in both ischemic and non-ischemic myocardium, while the β-adrenergic response to isoproterenol was depressed in both pathologies. CONCLUSIONS Force development at resting heart rate is not impacted by cardiac pathology, but kinetics are impaired and the magnitude of the impairment depends on the underlying etiology. Focusing on restoration of myocardial kinetics will likely have greater therapeutic potential than targeting force of contraction.
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Roldan Ramos S, Pieles G, Hui W, Slorach C, Redington AN, Friedberg MK. A rabbit model of progressive chronic right ventricular pressure overload. Interact Cardiovasc Thorac Surg 2018; 26:673-680. [PMID: 29211855 DOI: 10.1093/icvts/ivx372] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2017] [Accepted: 10/14/2017] [Indexed: 11/14/2022] Open
Abstract
OBJECTIVES Right ventricular (RV) failure from increased pressure loading is a frequent consequence of acquired and congenital heart diseases. However, the mechanisms involved in their pathophysiology are still unclear, and few data exist on RV pressure-loading models and early versus late effects on RV and left ventricular responses. We characterized a rabbit model of chronic RV pressure overload and early-late effects on biventricular function. METHODS Twenty-one New Zealand white rabbits were randomized into 3 groups: (i) sham, (ii) pulmonary artery (PA) banding (PAB) for 3 weeks (PAB3W) and (iii) PAB for 6 weeks (PAB6W). Progressive RV pressure overload was created by serial band inflation using an adjustable device. Molecular, echocardiographic and haemodynamic studies were performed. RESULTS RV pressure overload was achieved with clinical manifestations of RV failure. Heart and liver weights were significantly higher after PAB. PAB-induced echocardiographic ventricular remodelling increased wall thickness and stress and ventricular dilation. Cardiac output (ml/min) (sham 172.4 ± 42.86 vs PAB3W 103.1 ± 23.14 vs PAB6W 144 ± 60.9, P = 0.0027) and systolic and diastolic functions decreased; with increased RV end-systolic and end-diastolic pressures (mmHg) (sham 1.6 ± 0.66 vs PAB3W 3.9 ± 1.8 vs PAB6W 5.2 ± 2.2, P = 0.0103), despite increased contractility [end-systolic pressure-volume relationship (mmHg/ml), sham 3.76 ± 1.76 vs PAB3W 12.21 ± 3.44 vs PAB6W 19.4 ± 6.88, P < 0.0001]. Functional parameters further worsened after PAB6W versus PAB3W. LV contractility increased in both the PAB groups, despite worsening of other invasive measures of systolic and diastolic functions. CONCLUSIONS We describe a novel, unique model of chronic RV pressure overload leading to early biventricular dysfunction and fibrosis with further progression at 6 weeks. These findings can aid in guiding management.
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Affiliation(s)
- Sara Roldan Ramos
- Department of Paediatric Cardiology, Hospital for Sick Children, Toronto, ON, Canada
- Department of Congenital Cardiac Surgery, Bristol Heart Institute and Hospital for Sick Children, Bristol, UK
| | - Guido Pieles
- Department of Paediatric Cardiology, Hospital for Sick Children, Toronto, ON, Canada
- Department of Pediatric Cardiology, Bristol Heart Institute and Hospital for Sick Children, Bristol, UK
| | - Wei Hui
- Department of Paediatric Cardiology, Hospital for Sick Children, Toronto, ON, Canada
| | - Cameron Slorach
- Department of Paediatric Cardiology, Hospital for Sick Children, Toronto, ON, Canada
| | - Andrew N Redington
- Department of Paediatric Cardiology, Hospital for Sick Children, Toronto, ON, Canada
| | - Mark K Friedberg
- Department of Paediatric Cardiology, Hospital for Sick Children, Toronto, ON, Canada
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Monasky MM, Torres CAA, Janssen PML. Length-Dependent Prolongation of Force Relaxation Is Unaltered by Delay of Intracellular Calcium Decline in Early-Stage Rabbit Right Ventricular Hypertrophy. Front Physiol 2017; 8:945. [PMID: 29255420 PMCID: PMC5723014 DOI: 10.3389/fphys.2017.00945] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Accepted: 11/08/2017] [Indexed: 11/13/2022] Open
Abstract
Chronic pressure overload can result in ventricular hypertrophy and eventually diastolic dysfunction. In normal myocardium, the time from peak tension to 50% relaxation of isolated cardiac myocardium is not directly determined by the time for calcium decline. This study aims to determine whether the time for calcium decline is altered with a change in preload in early-stage hypertrophied myocardium, and whether this change in time for calcium decline alters the rate of relaxation of the myocardium. Young New Zealand white rabbits underwent a pulmonary artery banding procedure and were euthanized 10 weeks later. Twitch contractions and calibrated bis-fura-2 calcium transients were measured in isolated thin right ventricular trabeculae at optimal length and with the muscle taut. Systolic calcium, calcium transient amplitude, and time from peak tension to 50% relaxation all increased with an increase in preload for both hypertrophied and sham groups. Time for intracellular calcium decline increased both with an increase in preload and an increase in extracellular calcium concentration in hypertrophied myocardium but not in sham, while time from peak tension to 50% relaxation did not significantly change between groups under either condition. Also, time for intracellular calcium decline generally decreased with an increase in extracellular calcium for both hypertrophied and sham groups, while time from peak tension to 50% relaxation generally did not significantly change in either group. Combined, these results indicate that the mild hypertrophy significantly changes calcium handling, but does not impact on the rate of force relaxation. This implies that the rate-limiting step in force relaxation is not directly related to calcium transient decline.
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Affiliation(s)
- Michelle M Monasky
- Department of Physiology and Cell Biology, College of Medicine, Ohio State University, Columbus, OH, United States
| | - Carlos A A Torres
- Department of Physiology and Cell Biology, College of Medicine, Ohio State University, Columbus, OH, United States.,Department of Emergency Medicine, Ohio State University, Columbus, OH, United States
| | - Paul M L Janssen
- Department of Physiology and Cell Biology, College of Medicine, Ohio State University, Columbus, OH, United States
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Mendes-Ferreira P, Santos-Ribeiro D, Adão R, Maia-Rocha C, Mendes-Ferreira M, Sousa-Mendes C, Leite-Moreira AF, Brás-Silva C. Distinct right ventricle remodeling in response to pressure overload in the rat. Am J Physiol Heart Circ Physiol 2016; 311:H85-95. [PMID: 27199115 DOI: 10.1152/ajpheart.00089.2016] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/27/2016] [Accepted: 05/02/2016] [Indexed: 12/15/2022]
Abstract
Pulmonary arterial hypertension (PAH), the most serious chronic disorder of the pulmonary circulation, is characterized by pulmonary vasoconstriction and remodeling, resulting in increased afterload on the right ventricle (RV). In fact, RV function is the main determinant of prognosis in PAH. The most frequently used experimental models of PAH include monocrotaline- and chronic hypoxia-induced PAH, which primarily affect the pulmonary circulation. Alternatively, pulmonary artery banding (PAB) can be performed to achieve RV overload without affecting the pulmonary vasculature, allowing researchers to determine the RV-specific effects of their drugs/interventions. In this work, using two different degrees of pulmonary artery constriction, we characterize, in full detail, PAB-induced adaptive and maladaptive remodeling of the RV at 3 wk after PAB surgery. Our results show that application of a mild constriction resulted in adaptive hypertrophy of the RV, with preserved systolic and diastolic function, while application of a severe constriction resulted in maladaptive hypertrophy, with chamber dilation and systolic and diastolic dysfunction up to the isolated cardiomyocyte level. By applying two different degrees of constriction, we describe, for the first time, a reliable and short-duration PAB model in which RV adaptation can be distinguished at 3 wk after surgery. We characterize, in full detail, structural and functional changes of the RV in its response to moderate and severe constriction, allowing researchers to better study RV physiology and transition to dysfunction and failure, as well as to determine the effects of new therapies.
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Affiliation(s)
- P Mendes-Ferreira
- Deparment of Physiology and Cardiothoracic Surgery, Faculty of Medicine, University of Porto, Porto, Portugal; and
| | - D Santos-Ribeiro
- Deparment of Physiology and Cardiothoracic Surgery, Faculty of Medicine, University of Porto, Porto, Portugal; and
| | - R Adão
- Deparment of Physiology and Cardiothoracic Surgery, Faculty of Medicine, University of Porto, Porto, Portugal; and
| | - C Maia-Rocha
- Deparment of Physiology and Cardiothoracic Surgery, Faculty of Medicine, University of Porto, Porto, Portugal; and
| | - M Mendes-Ferreira
- Deparment of Physiology and Cardiothoracic Surgery, Faculty of Medicine, University of Porto, Porto, Portugal; and
| | - C Sousa-Mendes
- Deparment of Physiology and Cardiothoracic Surgery, Faculty of Medicine, University of Porto, Porto, Portugal; and
| | - A F Leite-Moreira
- Deparment of Physiology and Cardiothoracic Surgery, Faculty of Medicine, University of Porto, Porto, Portugal; and
| | - C Brás-Silva
- Deparment of Physiology and Cardiothoracic Surgery, Faculty of Medicine, University of Porto, Porto, Portugal; and Faculty of Nutrition and Food Sciences, University of Porto, Porto, Portugal
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Guilbert A, Lim HJ, Cheng J, Wang Y. CaMKII-dependent myofilament Ca2+ desensitization contributes to the frequency-dependent acceleration of relaxation. Cell Calcium 2015; 58:489-99. [PMID: 26297240 DOI: 10.1016/j.ceca.2015.08.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2015] [Revised: 07/06/2015] [Accepted: 08/04/2015] [Indexed: 11/15/2022]
Abstract
BACKGROUND Previous studies suggest that CaMKII activity is required for frequency-dependent acceleration of relaxation (FDAR) in ventricular myocytes. We propose that the underlying mechanism involves CaMKII-dependent regulation of myofilament Ca(2+) sensitivity. METHODS AND RESULTS Cardiac function was measured in mice using murine echo machine. [Ca(2+)]i and sarcomere length were measured by IonOptix Ca(2+) image system. Increasing pacing rate from 0.5 to 4 Hz in left ventricular myocytes induced frequency-dependent myofilament Ca(2+) desensitization (FDMCD) and FDAR. Acute inhibition of PKA or PKC had no effect, whereas CaMKII inhibition abolished both FDMCD and FDAR. Co-immunoprecipitation of CaMKII and troponin I (TnI) has been detected and CaMKII inhibition significantly reduced serine residue phosphorylation of TnI. Finally, chronic inhibition of CaMKII in vivo reduced TnI phosphorylation and abolished both FDAR and FDMCD, leading to impaired diastolic function. CONCLUSIONS Our results suggest that CaMKII-dependent TnI phosphorylation is involved in FDMCD and the consequent FDAR and that CaMKII inhibition removes this mechanism and thus induces diastolic dysfunction.
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Affiliation(s)
| | - Hyun Joung Lim
- Department of Pediatrics, Emory University, Atlanta, USA
| | - Jun Cheng
- Department of Cardiology, Zhongnan Hospital of Wuhan University, Wuhan University, China; Department of Pediatrics, Emory University, Atlanta, USA
| | - Yanggan Wang
- Department of Cardiology, Zhongnan Hospital of Wuhan University, Wuhan University, China; Department of Pediatrics, Emory University, Atlanta, USA.
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14
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Dissociation of Calcium Transients and Force Development following a Change in Stimulation Frequency in Isolated Rabbit Myocardium. BIOMED RESEARCH INTERNATIONAL 2015; 2015:468548. [PMID: 25961020 PMCID: PMC4413957 DOI: 10.1155/2015/468548] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/06/2014] [Revised: 08/01/2014] [Accepted: 08/19/2014] [Indexed: 01/02/2023]
Abstract
As the heart transitions from one exercise intensity to another, changes in cardiac output occur, which are modulated by alterations in force development and calcium handling. Although the steady-state force-calcium relationship at various heart rates is well investigated, regulation of these processes during transitions in heart rate is poorly understood. In isolated right ventricular muscle preparations from the rabbit, we investigated the beat-to-beat alterations in force and calcium during the transition from one stimulation frequency to another, using contractile assessments and confocal microscopy. We show that a change in steady-state conditions occurs in multiple phases: a rapid phase, which is characterized by a fast change in force production mirrored by a change in calcium transient amplitude, and a slow phase, which follows the rapid phase and occurs as the muscle proceeds to stabilize at the new frequency. This second/late phase is characterized by a quantitative dissociation between the calcium transient amplitude and developed force. Twitch timing kinetics, such as time to peak tension and 50% relaxation rate, reached steady-state well before force development and calcium transient amplitude. The dynamic relationship between force and calcium upon a switch in stimulation frequency unveils the dynamic involvement of myofilament-based properties in frequency-dependent activation.
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15
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Biesiadecki BJ, Davis JP, Ziolo MT, Janssen PML. Tri-modal regulation of cardiac muscle relaxation; intracellular calcium decline, thin filament deactivation, and cross-bridge cycling kinetics. Biophys Rev 2014; 6:273-289. [PMID: 28510030 PMCID: PMC4255972 DOI: 10.1007/s12551-014-0143-5] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Accepted: 06/27/2014] [Indexed: 01/09/2023] Open
Abstract
Cardiac muscle relaxation is an essential step in the cardiac cycle. Even when the contraction of the heart is normal and forceful, a relaxation phase that is too slow will limit proper filling of the ventricles. Relaxation is too often thought of as a mere passive process that follows contraction. However, many decades of advancements in our understanding of cardiac muscle relaxation have shown it is a highly complex and well-regulated process. In this review, we will discuss three distinct events that can limit the rate of cardiac muscle relaxation: the rate of intracellular calcium decline, the rate of thin-filament de-activation, and the rate of cross-bridge cycling. Each of these processes are directly impacted by a plethora of molecular events. In addition, these three processes interact with each other, further complicating our understanding of relaxation. Each of these processes is continuously modulated by the need to couple bodily oxygen demand to cardiac output by the major cardiac physiological regulators. Length-dependent activation, frequency-dependent activation, and beta-adrenergic regulation all directly and indirectly modulate calcium decline, thin-filament deactivation, and cross-bridge kinetics. We hope to convey our conclusion that cardiac muscle relaxation is a process of intricate checks and balances, and should not be thought of as a single rate-limiting step that is regulated at a single protein level. Cardiac muscle relaxation is a system level property that requires fundamental integration of three governing systems: intracellular calcium decline, thin filament deactivation, and cross-bridge cycling kinetics.
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Affiliation(s)
- Brandon J Biesiadecki
- Department of Physiology and Cell Biology and Dorothy M. Davis Heart Lung Institute, College of Medicine, The Ohio State University, 304 Hamilton Hall, 1645 Neil Avenue, Columbus, OH, 43210-1218, USA
| | - Jonathan P Davis
- Department of Physiology and Cell Biology and Dorothy M. Davis Heart Lung Institute, College of Medicine, The Ohio State University, 304 Hamilton Hall, 1645 Neil Avenue, Columbus, OH, 43210-1218, USA
| | - Mark T Ziolo
- Department of Physiology and Cell Biology and Dorothy M. Davis Heart Lung Institute, College of Medicine, The Ohio State University, 304 Hamilton Hall, 1645 Neil Avenue, Columbus, OH, 43210-1218, USA
| | - Paul M L Janssen
- Department of Physiology and Cell Biology and Dorothy M. Davis Heart Lung Institute, College of Medicine, The Ohio State University, 304 Hamilton Hall, 1645 Neil Avenue, Columbus, OH, 43210-1218, USA.
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16
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Dweck D, Sanchez-Gonzalez MA, Chang AN, Dulce RA, Badger CD, Koutnik AP, Ruiz EL, Griffin B, Liang J, Kabbaj M, Fincham FD, Hare JM, Overton JM, Pinto JR. Long term ablation of protein kinase A (PKA)-mediated cardiac troponin I phosphorylation leads to excitation-contraction uncoupling and diastolic dysfunction in a knock-in mouse model of hypertrophic cardiomyopathy. J Biol Chem 2014; 289:23097-23111. [PMID: 24973218 DOI: 10.1074/jbc.m114.561472] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The cardiac troponin I (cTnI) R21C (cTnI-R21C) mutation has been linked to hypertrophic cardiomyopathy and renders cTnI incapable of phosphorylation by PKA in vivo. Echocardiographic imaging of homozygous knock-in mice expressing the cTnI-R21C mutation shows that they develop hypertrophy after 12 months of age and have abnormal diastolic function that is characterized by longer filling times and impaired relaxation. Electrocardiographic analyses show that older R21C mice have elevated heart rates and reduced cardiovagal tone. Cardiac myocytes isolated from older R21C mice demonstrate that in the presence of isoproterenol, significant delays in Ca(2+) decay and sarcomere relaxation occur that are not present at 6 months of age. Although isoproterenol and stepwise increases in stimulation frequency accelerate Ca(2+)-transient and sarcomere shortening kinetics in R21C myocytes from older mice, they are unable to attain the corresponding WT values. When R21C myocytes from older mice are treated with isoproterenol, evidence of excitation-contraction uncoupling is indicated by an elevation in diastolic calcium that is frequency-dissociated and not coupled to shorter diastolic sarcomere lengths. Myocytes from older mice have smaller Ca(2+) transient amplitudes (2.3-fold) that are associated with reductions (2.9-fold) in sarcoplasmic reticulum Ca(2+) content. This abnormal Ca(2+) handling within the cell may be attributed to a reduction (2.4-fold) in calsequestrin expression in conjunction with an up-regulation (1.5-fold) of Na(+)-Ca(2+) exchanger. Incubation of permeabilized cardiac fibers from R21C mice with PKA confirmed that the mutation prevents facilitation of mechanical relaxation. Altogether, these results indicate that the inability to enhance myofilament relaxation through cTnI phosphorylation predisposes the heart to abnormal diastolic function, reduced accessibility of cardiac reserves, dysautonomia, and hypertrophy.
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Affiliation(s)
- David Dweck
- Department of Biomedical Sciences, Florida State University College of Medicine, Tallahassee, Florida 32306-4300
| | - Marcos A Sanchez-Gonzalez
- Department of Biomedical Sciences, Florida State University College of Medicine, Tallahassee, Florida 32306-4300,; Family Institute, Florida State University, Tallahassee, Florida 32306
| | - Audrey N Chang
- Department of Physiology, University of Texas Southwestern Medical Center, Dallas, Texas 75390-9040
| | - Raul A Dulce
- Interdisciplinary Stem Cell Institute, University of Miami Miller School of Medicine, Miami, Florida 33136, and
| | - Crystal-Dawn Badger
- Department of Biomedical Sciences, Florida State University College of Medicine, Tallahassee, Florida 32306-4300
| | - Andrew P Koutnik
- Department of Biomedical Sciences, Florida State University College of Medicine, Tallahassee, Florida 32306-4300
| | - Edda L Ruiz
- Department of Biomedical Sciences, Florida State University College of Medicine, Tallahassee, Florida 32306-4300
| | - Brittany Griffin
- Department of Biomedical Sciences, Florida State University College of Medicine, Tallahassee, Florida 32306-4300
| | - Jingsheng Liang
- Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine, Miami, Florida 33136
| | - Mohamed Kabbaj
- Department of Biomedical Sciences, Florida State University College of Medicine, Tallahassee, Florida 32306-4300
| | - Frank D Fincham
- Family Institute, Florida State University, Tallahassee, Florida 32306
| | - Joshua M Hare
- Interdisciplinary Stem Cell Institute, University of Miami Miller School of Medicine, Miami, Florida 33136, and
| | - J Michael Overton
- Department of Biomedical Sciences, Florida State University College of Medicine, Tallahassee, Florida 32306-4300
| | - Jose R Pinto
- Department of Biomedical Sciences, Florida State University College of Medicine, Tallahassee, Florida 32306-4300,.
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17
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Milani-Nejad N, Janssen PML. Small and large animal models in cardiac contraction research: advantages and disadvantages. Pharmacol Ther 2014; 141:235-49. [PMID: 24140081 PMCID: PMC3947198 DOI: 10.1016/j.pharmthera.2013.10.007] [Citation(s) in RCA: 305] [Impact Index Per Article: 30.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2013] [Accepted: 08/15/2013] [Indexed: 12/22/2022]
Abstract
The mammalian heart is responsible for not only pumping blood throughout the body but also adjusting this pumping activity quickly depending upon sudden changes in the metabolic demands of the body. For the most part, the human heart is capable of performing its duties without complications; however, throughout many decades of use, at some point this system encounters problems. Research into the heart's activities during healthy states and during adverse impacts that occur in disease states is necessary in order to strategize novel treatment options to ultimately prolong and improve patients' lives. Animal models are an important aspect of cardiac research where a variety of cardiac processes and therapeutic targets can be studied. However, there are differences between the heart of a human being and an animal and depending on the specific animal, these differences can become more pronounced and in certain cases limiting. There is no ideal animal model available for cardiac research, the use of each animal model is accompanied with its own set of advantages and disadvantages. In this review, we will discuss these advantages and disadvantages of commonly used laboratory animals including mouse, rat, rabbit, canine, swine, and sheep. Since the goal of cardiac research is to enhance our understanding of human health and disease and help improve clinical outcomes, we will also discuss the role of human cardiac tissue in cardiac research. This review will focus on the cardiac ventricular contractile and relaxation kinetics of humans and animal models in order to illustrate these differences.
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Affiliation(s)
- Nima Milani-Nejad
- Department of Physiology and Cell Biology and D. Davis Heart Lung Institute, College of Medicine, The Ohio State University, OH, USA
| | - Paul M L Janssen
- Department of Physiology and Cell Biology and D. Davis Heart Lung Institute, College of Medicine, The Ohio State University, OH, USA.
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18
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Milani-Nejad N, Xu Y, Davis JP, Campbell KS, Janssen PML. Effect of muscle length on cross-bridge kinetics in intact cardiac trabeculae at body temperature. ACTA ACUST UNITED AC 2013; 141:133-9. [PMID: 23277479 PMCID: PMC3536524 DOI: 10.1085/jgp.201210894] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
Dynamic force generation in cardiac muscle, which determines cardiac pumping activity, depends on both the number of sarcomeric cross-bridges and on their cycling kinetics. The Frank–Starling mechanism dictates that cardiac force development increases with increasing cardiac muscle length (corresponding to increased ventricular volume). It is, however, unclear to what extent this increase in cardiac muscle length affects the rate of cross-bridge cycling. Previous studies using permeabilized cardiac preparations, sub-physiological temperatures, or both have obtained conflicting results. Here, we developed a protocol that allowed us to reliably and reproducibly measure the rate of tension redevelopment (ktr; which depends on the rate of cross-bridge cycling) in intact trabeculae at body temperature. Using K+ contractures to induce a tonic level of force, we showed the ktr was slower in rabbit muscle (which contains predominantly β myosin) than in rat muscle (which contains predominantly α myosin). Analyses of ktr in rat muscle at optimal length (Lopt) and 90% of optimal length (L90) revealed that ktr was significantly slower at Lopt (27.7 ± 3.3 and 27.8 ± 3.0 s−1 in duplicate analyses) than at L90 (45.1 ± 7.6 and 47.5 ± 9.2 s−1). We therefore show that ktr can be measured in intact rat and rabbit cardiac trabeculae, and that the ktr decreases when muscles are stretched to their optimal length under near-physiological conditions, indicating that the Frank–Starling mechanism not only increases force but also affects cross-bridge cycling kinetics.
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Affiliation(s)
- Nima Milani-Nejad
- Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH 43210, USA
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19
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Hirt MN, Sörensen NA, Bartholdt LM, Boeddinghaus J, Schaaf S, Eder A, Vollert I, Stöhr A, Schulze T, Witten A, Stoll M, Hansen A, Eschenhagen T. Increased afterload induces pathological cardiac hypertrophy: a new in vitro model. Basic Res Cardiol 2012; 107:307. [PMID: 23099820 PMCID: PMC3505530 DOI: 10.1007/s00395-012-0307-z] [Citation(s) in RCA: 118] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/24/2012] [Revised: 10/16/2012] [Accepted: 10/17/2012] [Indexed: 12/22/2022]
Abstract
Increased afterload results in 'pathological' cardiac hypertrophy, the most important risk factor for the development of heart failure. Current in vitro models fall short in deciphering the mechanisms of hypertrophy induced by afterload enhancement. The aim of this study was to develop an experimental model that allows investigating the impact of afterload enhancement (AE) on work-performing heart muscles in vitro. Fibrin-based engineered heart tissue (EHT) was cast between two hollow elastic silicone posts in a 24-well cell culture format. After 2 weeks, the posts were reinforced with metal braces, which markedly increased afterload of the spontaneously beating EHTs. Serum-free, triiodothyronine-, and hydrocortisone-supplemented medium conditions were established to prevent undefined serum effects. Control EHTs were handled identically without reinforcement. Endothelin-1 (ET-1)- or phenylephrine (PE)-stimulated EHTs served as positive control for hypertrophy. Cardiomyocytes in EHTs enlarged by 28.4 % under AE and to a similar extent by ET-1- or PE-stimulation (40.6 or 23.6 %), as determined by dystrophin staining. Cardiomyocyte hypertrophy was accompanied by activation of the fetal gene program, increased glucose consumption, and increased mRNA levels and extracellular deposition of collagen-1. Importantly, afterload-enhanced EHTs exhibited reduced contractile force and impaired diastolic relaxation directly after release of the metal braces. These deleterious effects of afterload enhancement were preventable by endothelin-A, but not endothelin-B receptor blockade. Sustained afterload enhancement of EHTs alone is sufficient to induce pathological cardiac remodeling with reduced contractile function and increased glucose consumption. The model will be useful to investigate novel therapeutic approaches in a simple and fast manner.
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Affiliation(s)
- Marc N Hirt
- Department of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf and DZHK, Germany
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20
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Roof SR, Biesiadecki BJ, Davis JP, Janssen PML, Ziolo MT. Effects of increased systolic Ca(2+) and β-adrenergic stimulation on Ca(2+) transient decline in NOS1 knockout cardiac myocytes. Nitric Oxide 2012; 27:242-7. [PMID: 22960389 DOI: 10.1016/j.niox.2012.08.077] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2012] [Revised: 08/02/2012] [Accepted: 08/24/2012] [Indexed: 12/31/2022]
Abstract
We have previously shown that the main factor responsible for the faster [Ca(2+)](i) decline rate with β-adrenergic (β-AR) stimulation is the phosphorylation of phospholamban (PLB) rather than the increase in systolic Ca(2+) levels. The purpose of this study was to correlate the extent of augmentation of PLB Serine(16) phosphorylation to the rate of [Ca(2+)](i) decline. Thus, ventricular myocytes were isolated from neuronal nitric oxide synthase knockout (NOS1(-/-)) mice, which we observed had lower basal PLB Serine(16) phosphorylation levels, but equal levels during β-AR stimulation. Ca(2+) transients (Fluo-4) were measured in myocytes superfused with 3mM extracellular Ca(2+) ([Ca(2+)](o)) and a non-specific β-AR agonist isoproterenol (ISO, 1μM) with 1mM [Ca(2+)](o). This allowed us to get matched Ca(2+) transient amplitudes in the same myocyte. Similar to our previous work, Ca(2+) transient decline was significantly faster with ISO compared to 3mM [Ca(2+)](o), even with matched Ca(2+) transient amplitudes. Interestingly, when we compared the effects of ISO on Ca(2+) transient decline between NOS1(-/-) and WT myocytes, ISO had a larger effect in NOS1(-/-) myocytes, which resulted in a greater percent decrease in the Ca(2+) transient RT(50). We believe this is due to a greater augmentation of PLB Serine16 phosphorylation in these myocytes. Thus, our results suggest that not only the amount but the extent of augmentation of PLB Serine(16) phosphorylation are the major determinants for the Ca(2+) decline rate. Furthermore, our data suggest that the molecular mechanisms of Ca(2+) transient decline is normal in NOS1(-/-) myocytes and that the slow basal Ca(2+) transient decline is predominantly due to decreased PLB phosphorylation.
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Affiliation(s)
- Steve R Roof
- Department of Physiology & Cell Biology, Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH 43210, USA
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21
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Haizlip KM, Hiranandani N, Biesiadecki BJ, Janssen PML. Impact of hydroxyl radical-induced injury on calcium handling and myofilament sensitivity in isolated myocardium. J Appl Physiol (1985) 2012; 113:766-74. [PMID: 22773772 DOI: 10.1152/japplphysiol.01424.2011] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Hydroxyl radicals (OH) are involved in the pathogenesis of reperfusion injury and are observed in acute heart failure, stroke, and myocardial infarction. Two different subcellular defects are involved in the pathogenesis of OH injury, deranged calcium handling, and alterations of myofilament responsiveness, but their temporal impact on contractile function is not resolved. Initially, after brief OH exposure, there is a corresponding marked increase in diastolic calcium and diastolic force. We followed these parameters until a new steady-state level was reached at ~45 min post-OH exposure. At this new baseline, diastolic calcium had returned to near-normal, pre-OH levels, whereas diastolic force remained markedly elevated. An increased calcium sensitivity was observed at the new baseline after OH-induced injury compared with the pre-OH state. The acute injury that occurs after OH exposure is mainly due to calcium overload, while the later sustained myocardial dysfunction is mainly due to the altered/increased myofilament responsiveness.
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Affiliation(s)
- Kaylan M Haizlip
- Department of Physiology and Cell Biology, Ohio State University, Columbus, Ohio 43210-1218, USA
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22
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Staurosporine inhibits frequency-dependent myofilament desensitization in intact rabbit cardiac trabeculae. Biochem Res Int 2012; 2012:290971. [PMID: 22649731 PMCID: PMC3357507 DOI: 10.1155/2012/290971] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2012] [Accepted: 02/22/2012] [Indexed: 11/17/2022] Open
Abstract
Myofilament calcium sensitivity decreases with frequency in intact healthy rabbit trabeculae and associates with Troponin I and Myosin light chain-2 phosphorylation. We here tested whether serine-threonine kinase activity is primarily responsible for this frequency-dependent modulations of myofilament calcium sensitivity. Right ventricular trabeculae were isolated from New Zealand White rabbit hearts and iontophoretically loaded with bis-fura-2. Twitch force-calcium relationships and steady state force-calcium relationships were measured at frequencies of 1 and 4 Hz at 37 °C. Staurosporine (100 nM), a nonspecific serine-threonine kinase inhibitor, or vehicle (DMSO) was included in the superfusion solution before and during the contractures. Staurosporine had no frequency-dependent effect on force development, kinetics, calcium transient amplitude, or rate of calcium transient decline. The shift in the pCa50 of the force-calcium relationship was significant from 6.05 ± 0.04 at 1 Hz versus 5.88 ± 0.06 at 4 Hz under control conditions (vehicle, P < 0.001) but not in presence of staurosporine (5.89 ± 0.08 at 1 Hz versus 5.94 ± 0.07 at 4 Hz, P = NS). Phosphoprotein analysis (Pro-Q Diamond stain) confirmed that staurosporine significantly blunted the frequency-dependent phosphorylation at Troponin I and Myosin light chain-2. We conclude that frequency-dependent modulation of calcium sensitivity is mediated through a kinase-specific effect involving phosphorylation of myofilament proteins.
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Haizlip KM, Bupha-Intr T, Biesiadecki BJ, Janssen PML. Effects of increased preload on the force-frequency response and contractile kinetics in early stages of cardiac muscle hypertrophy. Am J Physiol Heart Circ Physiol 2012; 302:H2509-17. [PMID: 22467304 DOI: 10.1152/ajpheart.00660.2011] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Numerous studies have aimed to elucidate markers for the onset of decompensatory hypertrophy and heart failure in vivo and in vitro. Alterations in the force-frequency relationship are commonly used as markers for heart failure with a negative staircase being a hallmark of decompensated cardiac function. Here we aim to determine the functional and molecular alterations in the very early stages of compensatory hypertrophy through analysis of the force-frequency relationship, using a novel isolated muscle culture system that allows assessment of force-frequency relationship during the development of hypertrophy. New Zealand white male rabbit trabeculae excised from the right ventricular free wall were utilized for all experiments. Briefly, muscles held at constant preload and contracting isometrically were stimulated to contract in culture for 24 h, and in a subset up to 48 h. We found that, upon an increase in the preload and maintaining the muscles in culture for up to 24 h, there was an increase in baseline force produced by isolated trabeculae over time. This suggests a gradual compensatory response to the impact of increased preload. Temporal analysis of the force-frequency response during this progression revealed a significant blunting (at 12 h) and then reversal of the positive staircase as culture time increased (at 24 h). Phosphorylation analysis revealed a significant decrease in desmin and troponin (Tn)I phosphorylation from 12 to 24 h in culture. These results show that even very early on in the compensatory hypertrophy state, the force-frequency relationship is already affected. This effect on force-frequency relationship may, in addition to protein expression changes, be partially attributed to the alterations in myofilament protein phosphorylation.
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Affiliation(s)
- Kaylan M Haizlip
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, Ohio 43210-1218, USA
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24
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Slabaugh JL, Brunello L, Gyorke S, Janssen PML. Contractile parameters and occurrence of alternans in isolated rat myocardium at supra-physiological stimulation frequency. Am J Physiol Heart Circ Physiol 2012; 302:H2267-75. [PMID: 22467303 DOI: 10.1152/ajpheart.01004.2011] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The cardiac refractory period prevents the heart from tetanic activation that is typically used in noncardiac striated muscle tissue. To what extent the refractory period prevents successive action potentials to activate the excitation-contraction coupling process and contractile machinery at supra-physiological rates, such as those present during ventricular fibrillation, is unknown. Using multicellular trabeculae isolated from rat hearts, we studied amplitude and kinetics of contraction at rates well above the normal in vivo rat heart range. We show that even at twice the maximal heart rate of the rat, little or no mechanical instability is observed; twitch contractions are at steady state, albeit with an elevated active diastolic force. Although the amplitude of contraction increased within in vivo heart rates (positive force-frequency response), at frequencies beyond the maximal heart rate (10-30 Hz) a steady decline of contractile amplitude is observed. Not until 30 Hz do the majority of the isolated muscle preparations show mechanical alternans, where strong and weak beats alternate. Interestingly, unlike striated limb skeletal muscle, fusing of twitch contractions did not cause a continuous increase in peak force: at frequencies of 10 Hz and above, systolic force declines with relatively little elevation in diastolic force. Contractile kinetics continued to accelerate, from 1 Hz up to 30 Hz, whereas the relative speed of contraction and relaxation remained closely coupled, reflected by a singular linear relationship between the maximal and minimal derivative of force (dF/dt). We conclude that cardiac muscle can produce mechanically stable steady-state contractions at supra-physiological pacing rates, while these contractions continue to decline in amplitude and increase in diastolic force past maximal heart rate.
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Affiliation(s)
- Jessica L Slabaugh
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, 43210-1218, USA
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25
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Xu Y, Monasky MM, Hiranandani N, Haizlip KM, Billman GE, Janssen PML. Effect of twitch interval duration on the contractile function of subsequent twitches in isolated rat, rabbit, and dog myocardium under physiological conditions. J Appl Physiol (1985) 2011; 111:1159-67. [PMID: 21778421 DOI: 10.1152/japplphysiol.01170.2010] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Many studies have shown that a change in stimulation frequency leads to altered contractility of the myocardium. However, it remains unclear what changes occur directly after a change in frequency and which ones are a result of the slow processes that lead to the altered homeostasis, which develops after a change in stimulation frequency. To distinguish the immediate from the slow responses, we assessed contractile function in two species that have distinctively different calcium (Ca(2+))-handling properties using a recently developed, randomized pacing protocol. In isolated dog and rat right ventricular trabeculae, twitch contractions at five different cycle lengths within the physiologic range of each species were randomized around a steady-state frequency. We found, in both species, that the duration of the cycle length just prior to the analyzed twitch (primary) positively correlated with the increased force of the analyzed twitch. In sharp contrast, the cycle lengths, one and two more removed from the analyzed twitch ("secondary" and "tertiary"), displayed a negative correlation with force of the analyzed twitch. In additional experiments, assessment of intracellular Ca(2+) transients in rabbit trabeculae revealed that diastolic Ca(2+) levels were closely correlated to contractile function outcome. The relative contribution of the primary cycle length was different between dog (51%) and rat (71%), whereas in neither species was a significant effect on relaxation time observed. With the use of randomized cycle lengths, we have distinguished the intrinsic response from the signaling-mediated effects of frequency-dependent activation on myofilament properties and Ca(2+) handling.
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Affiliation(s)
- Ying Xu
- Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, Ohio, USA
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26
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Haizlip KM, Janssen PML. In vitro studies of early cardiac remodeling: impact on contraction and calcium handling. Front Biosci (Schol Ed) 2011; 3:1047-57. [PMID: 21622254 DOI: 10.2741/209] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Cardiac remodeling, hypertrophy, and alterations in calcium signaling are changes of the heart that often lead to failure. After a hypertrophic stimulus, the heart progresses through a state of compensated hypertrophy which over time leads to decompensated hypertrophy or failure. It is at this point that a cardiac transplant is required for survival making early detection imperative. Current experimental systems used to study the remodeling of the heart include in vivo systems (the whole body), isolated organ and sub-organ tissue, and the individual cardiac muscle cells and organelles.. During pathological remodeling there is a derangement in the intracellular calcium handling processes. These derangements are thought to lead to a dysregulation of contractile output. Hence, understanding the mechanism between remodeling and dysregulation is of great interest in the cardiac field and will ultimately help in the development of future treatment and early detection. This review will center on changes in contraction and calcium handling in early cardiac remodeling, with a specific focus on findings in two different in vitro model systems: multicellular and individual cell preparations.
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Affiliation(s)
- Kaylan M Haizlip
- Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH 43210-1218, USA
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Diastolic myofilament dysfunction in the failing human heart. Pflugers Arch 2011; 462:155-63. [PMID: 21487693 PMCID: PMC3114087 DOI: 10.1007/s00424-011-0960-3] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2011] [Revised: 03/23/2011] [Accepted: 03/24/2011] [Indexed: 01/06/2023]
Abstract
In recent years, it has become evident that heart failure is not solely due to reduced contractile performance of the heart muscle as impaired relaxation is evident in almost all heart failure patients. In more than half of all heart failure patients, diastolic dysfunction is the major cardiac deficit. These heart failure patients have normal (or preserved) left ventricular ejection fraction, but impaired diastolic function evident from increased left ventricular end-diastolic pressure. Perturbations at the cellular level which cause impaired relaxation of the heart muscle involve changes in Ca(2+)-handling proteins, extracellular matrix components, and myofilament properties. The present review discusses the deficits in myofilament function observed in human heart failure and the most likely underlying causal protein changes. Moreover, the consequences of impaired myofilament function for in vivo diastolic dysfunction are discussed taking into account the reported changes in Ca(2+) handling.
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Hiranandani N, Billman GE, Janssen PML. Effects of hydroxyl radical induced-injury in atrial versus ventricular myocardium of dog and rabbit. Front Physiol 2010; 1:25. [PMID: 21423367 PMCID: PMC3059949 DOI: 10.3389/fphys.2010.00025] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2010] [Accepted: 07/22/2010] [Indexed: 11/13/2022] Open
Abstract
Despite the widespread use of ventricular tissue in the investigation involving hydroxyl radical Aim: (OH*) injury, one of the most potent mediators in ischemia-reperfusion injury, little is known about the impact on atrial myocardium. In this study we thus compared the OH*-induced injury response between atrial and right ventricular muscles from both rabbits and dogs under identical experimental conditions. Methods: Small, contracting ventricular and atrial rabbit and dog trabeculae were directly exposed to OH*, and contractile properties were examined and quantified. Results: A brief OH* exposure led to transient rigor like contracture with marked elevation of diastolic tension and depression of developed force. Although the injury response showed similarities between atrial and ventricular myocardium, there were significant differences as well. In rabbit atrial muscles, the development of the contracture and its peak was much faster as compared to ventricular muscles. Also, at the peak of contracture, both rabbit and dog atrial muscles show a lesser degree of contractile dysfunction. Conclusion:These results indicate that both atrial and ventricular muscles develop a rigor-like contracture after acute OH*-induced injury, and atrial muscles showed a lesser degree of contractile dysfunction. Comparison of dog versus rabbit tissue shows that the response was similar in magnitude, but slower to develop in dog tissue.
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Affiliation(s)
- Nitisha Hiranandani
- Department of Physiology and Cell Biology, College of Medicine, The Ohio State University Columbus, OH, USA
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Abstract
Since the pioneering work of Henry Pickering Bowditch in the late 1800s to early 1900s, cardiac muscle contraction has remained an intensely studied topic for several reasons. The heart is located centrally in our body, and its pumping motion demands the attention of the observer. The contraction of the heart encompasses a complex interplay of mechanical, chemical, and electrical properties, and its function can thus be studied from any of these viewpoints. In addition, diseases of the heart are currently killing more people in the Westernized world than any other disease. When combined with the increasing emphasis of research to be clinically relevant, this contributes to the heart remaining a topic of continued basic and clinical investigation. Yet, there are significant aspects of cardiac muscle contraction that are still not well understood. A big complication of the study of cardiac muscle contraction is that there exists no equilibrium among many of the important governing parameters, which include pre- and afterload, intracellular ion concentrations, membrane potential, and velocity and direction of movement. Thus the classic approach of perturbing an equilibrium or a steady state to learn about the role of the perturbing factor in the system cannot be unambiguously interpreted, since each of the parameters that govern contraction are constantly changing, as well as constantly changing their interaction with each other. In this review, presented as the 54th Bowditch Lecture at Experimental Biology meeting in Anaheim in April 2010, I will revisit several governing factors of cardiac muscle relaxation by applying newly developed tools and protocols to isolated cardiac muscle tissue in which the dynamic interactions between the governing factors of contraction and relaxation can be studied.
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Affiliation(s)
- Paul M L Janssen
- Department of Physiology and Cell Biology and D. Davis Heart Lung Institute, College of Medicine, The Ohio State University, Columbus, Ohio 43210-1218, USA.
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Panyasing Y, Kijtawornrat A, del Rio C, Carnes C, Hamlin RL. Uni- or bi-ventricular hypertrophy and susceptibility to drug-induced torsades de pointes. J Pharmacol Toxicol Methods 2010; 62:148-56. [DOI: 10.1016/j.vascn.2010.04.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2010] [Accepted: 04/16/2010] [Indexed: 11/28/2022]
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Why does troponin I have so many phosphorylation sites? Fact and fancy. J Mol Cell Cardiol 2010; 48:810-6. [PMID: 20188739 DOI: 10.1016/j.yjmcc.2010.02.014] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2009] [Revised: 02/18/2010] [Accepted: 02/18/2010] [Indexed: 11/23/2022]
Abstract
We discuss a current controversy regarding the relative role of phosphorylation sites on cardiac troponin I (cTnI) (Fig. 1) in physiological and patho-physiological cardiac function. Studies with mouse models and in vitro studies indicate that multi-site phosphorylations are involved in both control of maximum tension and sarcomeric responsiveness to Ca(2+). Thus one hypothesis is that cardiac function reflects a balance of cTnI phosphorylations and a tilt in this balance may be maladaptive in acquired and genetic disorders of the heart. Studies on human heart samples taken mainly at end-stage heart failure, and in depth proteomic analysis of human and rat heart samples demonstrate that Ser23/Ser24 are the major and perhaps the only sites likely to be relevant to control cardiac function. Thus functional significance of Ser23/Ser24 phosphorylation is taken as fact, whereas the function of some other sites is treated as fancy. Maybe the extremes will meet: in any case we both agree that further work needs to be carried out with relatively large mammals and with determination of the time course of changes in phosphorylation to identify transient modifications that may be relevant at a beat-to-beat basis. Moreover, we agree that the changes and effects of cTnI phosphorylation need to be fully integrated into the effects of other phosphorylations in the cardiac myocyte.
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Varian KD, Xu Y, Torres CAA, Monasky MM, Janssen PML. A random cycle length approach for assessment of myocardial contraction in isolated rabbit myocardium. Am J Physiol Heart Circ Physiol 2009; 297:H1940-8. [PMID: 19749159 PMCID: PMC2781388 DOI: 10.1152/ajpheart.01289.2008] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/12/2008] [Accepted: 09/07/2009] [Indexed: 11/22/2022]
Abstract
It is well known that the strength of cardiac contraction is dependent on the cycle length, evidenced by the force-frequency relationship (FFR) and the existence of postrest potentiation (PRP). Because the contractile strength of the steady-state FFR and force-interval relationship involve instant intrinsic responses to cycle length as well as slower acting components such as posttranslational modification-based mechanisms, it remains unclear how cycle length intrinsically affects cardiac contraction and relaxation. To dissect the impact of cycle length changes from slower acting signaling components associated with persisting changes in cycle length, we developed a novel technique/protocol to study cycle length-dependent effects on cardiac function; twitch contractions of right ventricular rabbit trabeculae at different cycle lengths were randomized around a steady-state frequency. Patterns of cycle lengths that resulted in changes in force and/or relaxation times can now be identified and analyzed. Using this novel protocol, taking under 10 min to complete, we found that the duration of the cycle length before a twitch contraction ("primary" cycle length) positively correlated with force. In sharp contrast, the cycle length one ("secondary") or two ("tertiary") beats before the analyzed twitch correlated negatively with force. Using this protocol, we can quantify the intrinsic effect of cycle length on contractile strength while avoiding rundown and lengthiness that are often complications of FFR and PRP assessments. The data show that the history of up to three cycle lengths before a contraction influences myocardial contractility and that primary cycle length affects cardiac twitch dynamics in the opposite direction from secondary/tertiary cycle lengths.
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Affiliation(s)
- Kenneth D Varian
- Department of Physiology and Cell Biology and D. Davis Heart Lung Institute, College of Medicine, The Ohio State University, Columbus, OH 43210-1218, USA
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