1
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Zhao Q, Chen Z, Qi C, Xu S, Ren R, Li W, Zhang X, Zhang Y. Cardiac magnetic resonance imaging for discrimination of hypertensive heart disease and hypertrophic cardiomyopathy: a systematic review and meta-analysis. Front Cardiovasc Med 2024; 11:1421013. [PMID: 39156132 PMCID: PMC11327824 DOI: 10.3389/fcvm.2024.1421013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2024] [Accepted: 07/19/2024] [Indexed: 08/20/2024] Open
Abstract
Introduction Differentiating hypertensive heart disease (HHD) from hypertrophic cardiomyopathy (HCM) is crucial yet challenging due to overlapping clinical and morphological features. Recent studies have explored the use of various cardiac magnetic resonance (CMR) parameters to distinguish between these conditions, but findings have remained inconclusive. This study aims to identify which CMR parameters effectively discriminate between HHD and HCM and to investigate their underlying pathophysiological mechanisms through a meta-analysis. Methods The researchers conducted a systematic and comprehensive search for all studies that used CMR to discriminate between HHD and HCM and calculated the Hedges'g effect size for each of the included studies, which were then pooled using a random-effects model and tested for the effects of potential influencing variables through subgroup and regression analyses. Results In this review, 26 studies encompassing 1,349 HHD and 1,581 HCM cases were included for meta-analysis. Analysis revealed that HHD showed a significant lower in T1 mapping (g = -0.469, P < 0.001), extracellular volume (g = -0.417, P = 0.024), left ventricular mass index (g = -0.437, P < 0.001), and maximal left ventricular wall thickness (g = -2.076, P < 0.001), alongside a significant higher in end-systolic volume index (g = 0.993, P < 0.001) and end-diastolic volume index (g = 0.553, P < 0.001), compared to HCM. Conclusion This study clearly demonstrates that CMR parameters can effectively differentiate between HHD and HCM. HHD is characterized by significantly lower diffuse interstitial fibrosis and myocardial hypertrophy, along with better-preserved diastolic function but lower systolic function, compared to HCM. The findings highlight the need for standardized CMR protocols, considering the significant influence of MRI machine vendors, post-processing software, and study regions on diagnostic parameters. These insights are crucial for improving diagnostic accuracy and optimizing treatment strategies for patients with HHD and HCM. Systematic Review Registration https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42023470557, PROSPERO (CRD42023470557).
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Affiliation(s)
| | | | | | | | | | | | | | - Yang Zhang
- Department of Radiology, Qilu Hospital of Shandong University, Jinan, China
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2
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Irving M. Functional control of myosin motors in the cardiac cycle. Nat Rev Cardiol 2024:10.1038/s41569-024-01063-5. [PMID: 39030271 DOI: 10.1038/s41569-024-01063-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 07/02/2024] [Indexed: 07/21/2024]
Abstract
Contraction of the heart is driven by cyclical interactions between myosin and actin filaments powered by ATP hydrolysis. The modular structure of heart muscle and the organ-level synchrony of the heartbeat ensure tight reciprocal coupling between this myosin ATPase cycle and the macroscopic cardiac cycle. The myosin motors respond to the cyclical activation of the actin and myosin filaments to drive the pressure changes that control the inflow and outflow valves of the heart chambers. Opening and closing of the valves in turn switches the myosin motors between roughly isometric and roughly isotonic contraction modes. Peak filament stress in the heart is much smaller than in fully activated skeletal muscle, although the myosin filaments in the two muscle types have the same number of myosin motors. Calculations indicate that only ~5% of the myosin motors in the heart are needed to generate peak systolic pressure, although many more motors are needed to drive ejection. Tight regulation of the number of active motors is essential for the efficient functioning of the healthy heart - this control is commonly disrupted by gene variants associated with inherited heart disease, and its restoration might be a useful end point in the development of novel therapies.
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Affiliation(s)
- Malcolm Irving
- Randall Centre for Cell and Molecular Biophysics and BHF Centre for Research Excellence, King's College London, London, UK.
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3
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Pardon G, Vander Roest AS, Chirikian O, Birnbaum F, Lewis H, Castillo EA, Wilson R, Denisin AK, Blair CA, Holbrook C, Koleckar K, Chang ACY, Blau HM, Pruitt BL. Tracking single hiPSC-derived cardiomyocyte contractile function using CONTRAX an efficient pipeline for traction force measurement. Nat Commun 2024; 15:5427. [PMID: 38926342 PMCID: PMC11208611 DOI: 10.1038/s41467-024-49755-3] [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: 03/17/2021] [Accepted: 06/18/2024] [Indexed: 06/28/2024] Open
Abstract
Cardiomyocytes derived from human induced pluripotent stem cells (hiPSC-CMs) are powerful in vitro models to study the mechanisms underlying cardiomyopathies and cardiotoxicity. Quantification of the contractile function in single hiPSC-CMs at high-throughput and over time is essential to disentangle how cellular mechanisms affect heart function. Here, we present CONTRAX, an open-access, versatile, and streamlined pipeline for quantitative tracking of the contractile dynamics of single hiPSC-CMs over time. Three software modules enable: parameter-based identification of single hiPSC-CMs; automated video acquisition of >200 cells/hour; and contractility measurements via traction force microscopy. We analyze >4,500 hiPSC-CMs over time in the same cells under orthogonal conditions of culture media and substrate stiffnesses; +/- drug treatment; +/- cardiac mutations. Using undirected clustering, we reveal converging maturation patterns, quantifiable drug response to Mavacamten and significant deficiencies in hiPSC-CMs with disease mutations. CONTRAX empowers researchers with a potent quantitative approach to develop cardiac therapies.
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Grants
- K99 HL153679 NHLBI NIH HHS
- RM1 GM131981 NIGMS NIH HHS
- 20POST35211011 American Heart Association (American Heart Association, Inc.)
- 17CSA33590101 American Heart Association (American Heart Association, Inc.)
- 18CDA34110411 American Heart Association (American Heart Association, Inc.)
- 1R21HL13099301 U.S. Department of Health & Human Services | NIH | National Heart, Lung, and Blood Institute (NHLBI)
- 18POST34080160 American Heart Association (American Heart Association, Inc.)
- 1F31HL158227 U.S. Department of Health & Human Services | NIH | National Heart, Lung, and Blood Institute (NHLBI)
- F31 HL158227 NHLBI NIH HHS
- 201411MFE-338745-169197 Gouvernement du Canada | Canadian Institutes of Health Research (Instituts de Recherche en Santé du Canada)
- P2SKP2_164954 Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung (Swiss National Science Foundation)
- 13POST14480004 American Heart Association (American Heart Association, Inc.)
- RM1GM131981 U.S. Department of Health & Human Services | NIH | National Heart, Lung, and Blood Institute (NHLBI)
- 82070248 National Natural Science Foundation of China (National Science Foundation of China)
- P400PM_180825 Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung (Swiss National Science Foundation)
- U.S. Department of Health & Human Services | NIH | National Heart, Lung, and Blood Institute (NHLBI)
- Shanghai Pujiang Program 19PJ1407000 Program for Professor of Special Appointment (Eastern Scholar) at Shanghai Institutions of Higher Learning 0900000024 to A.C.Y.C. Innovative Research Team of High-Level Local Universities in Shanghai (A.C.Y.C.)
- the Baxter Foundation, Li Ka Shing Foundation and The Stanford Cardiovascular Institute
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Affiliation(s)
- Gaspard Pardon
- Departments of Mechanical Engineering and of Bioengineering, Stanford University, School of Engineering and School of Medicine, Stanford, CA, USA
- Baxter Laboratory for Stem Cell Biology, Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA, USA
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA, USA
- Departments of Bioengineering and Mechanical Engineering, University of California, Santa Barbara, CA, USA
- School of Life Sciences, EPFL École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Alison S Vander Roest
- Departments of Mechanical Engineering and of Bioengineering, Stanford University, School of Engineering and School of Medicine, Stanford, CA, USA
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA, USA
- Department of Pediatrics (Cardiology), Stanford University School of Medicine, Stanford, CA, USA
- Department of Biomedical Engineering, Michigan Engineering, University of Michigan Ann Arbor, MI, USA
| | - Orlando Chirikian
- Biomolecular Science and Engineering Program, University of California, Santa Barbara, CA, USA
| | - Foster Birnbaum
- Baxter Laboratory for Stem Cell Biology, Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA, USA
| | - Henry Lewis
- Departments of Mechanical Engineering and of Bioengineering, Stanford University, School of Engineering and School of Medicine, Stanford, CA, USA
| | - Erica A Castillo
- Departments of Mechanical Engineering and of Bioengineering, Stanford University, School of Engineering and School of Medicine, Stanford, CA, USA
- Departments of Bioengineering and Mechanical Engineering, University of California, Santa Barbara, CA, USA
| | - Robin Wilson
- Departments of Mechanical Engineering and of Bioengineering, Stanford University, School of Engineering and School of Medicine, Stanford, CA, USA
| | - Aleksandra K Denisin
- Departments of Mechanical Engineering and of Bioengineering, Stanford University, School of Engineering and School of Medicine, Stanford, CA, USA
| | - Cheavar A Blair
- Departments of Mechanical Engineering and of Bioengineering, Stanford University, School of Engineering and School of Medicine, Stanford, CA, USA
- Departments of Bioengineering and Mechanical Engineering, University of California, Santa Barbara, CA, USA
- Department of Physiology, University of Kentucky, Lexington, KY, USA
| | - Colin Holbrook
- Baxter Laboratory for Stem Cell Biology, Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA, USA
| | - Kassie Koleckar
- Baxter Laboratory for Stem Cell Biology, Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA, USA
| | - Alex C Y Chang
- Baxter Laboratory for Stem Cell Biology, Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA, USA
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA, USA
- Shanghai Institute of Precision Medicine and Department of Cardiology, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200125, China
- Division of Cardiovascular Medicine, Stanford University School of Medicine, Stanford, CA, USA
| | - Helen M Blau
- Baxter Laboratory for Stem Cell Biology, Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA, USA
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA, USA
| | - Beth L Pruitt
- Departments of Mechanical Engineering and of Bioengineering, Stanford University, School of Engineering and School of Medicine, Stanford, CA, USA.
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA, USA.
- Departments of Bioengineering and Mechanical Engineering, University of California, Santa Barbara, CA, USA.
- Biomolecular Science and Engineering Program, University of California, Santa Barbara, CA, USA.
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4
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Dewan S, Witayavanitkul N, Kumar M, Mayer BJ, Betancourt L, Cazorla O, de Tombe PP. Depressed myocardial cross-bridge cycling kinetics in a female guinea pig model of diastolic heart failure. J Gen Physiol 2023; 155:e202213288. [PMID: 37102986 PMCID: PMC10140646 DOI: 10.1085/jgp.202213288] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Revised: 02/10/2023] [Accepted: 04/17/2023] [Indexed: 04/28/2023] Open
Abstract
Cardiac hypertrophy is associated with diastolic heart failure (DHF), a syndrome in which systolic function is preserved but cardiac filling dynamics are depressed. The molecular mechanisms underlying DHF and the potential role of altered cross-bridge cycling are poorly understood. Accordingly, chronic pressure overload was induced by surgically banding the thoracic ascending aorta (AOB) in ∼400 g female Dunkin Hartley guinea pigs (AOB); Sham-operated age-matched animals served as controls. Guinea pigs were chosen to avoid the confounding impacts of altered myosin heavy chain (MHC) isoform expression seen in other small rodent models. In vivo cardiac function was assessed by echocardiography; cardiac hypertrophy was confirmed by morphometric analysis. AOB resulted in left ventricle (LV) hypertrophy and compromised diastolic function with normal systolic function. Biochemical analysis revealed exclusive expression of β-MHC isoform in both sham control and AOB LVs. Myofilament function was assessed in skinned multicellular preparations, skinned single myocyte fragments, and single myofibrils prepared from frozen (liquid N2) LVs. The rates of force-dependent ATP consumption (tension-cost) and force redevelopment (Ktr), as well as myofibril relaxation time (Timelin) were significantly blunted in AOB, indicating reduced cross-bridge cycling kinetics. Maximum Ca2+ activated force development was significantly reduced in AOB myocytes, while no change in myofilament Ca2+ sensitivity was observed. Our results indicate blunted cross-bridge cycle in a β-MHC small animal DHF model. Reduced cross-bridge cycling kinetics may contribute, at least in part, to the development of DHF in larger mammals, including humans.
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Affiliation(s)
- Sukriti Dewan
- Department of Physiology and Biophysics, College of Medicine, University of Illinois at Chicago, Chicago, IL, USA
- Department of Cell and Molecular Physiology, Stritch School of Medicine, Loyola University Chicago, Maywood, IL, USA
| | - Namthip Witayavanitkul
- Department of Physiology and Biophysics, College of Medicine, University of Illinois at Chicago, Chicago, IL, USA
- Department of Cell and Molecular Physiology, Stritch School of Medicine, Loyola University Chicago, Maywood, IL, USA
| | - Mohit Kumar
- Department of Cell and Molecular Physiology, Stritch School of Medicine, Loyola University Chicago, Maywood, IL, USA
| | - Beth J Mayer
- Department of Cell and Molecular Physiology, Stritch School of Medicine, Loyola University Chicago, Maywood, IL, USA
| | - Lauren Betancourt
- Phymedexp INSERM, CNRS, University of Montpellier , Montpellier, France
| | - Olivier Cazorla
- Phymedexp INSERM, CNRS, University of Montpellier , Montpellier, France
| | - Pieter P de Tombe
- Department of Physiology and Biophysics, College of Medicine, University of Illinois at Chicago, Chicago, IL, USA
- Department of Cell and Molecular Physiology, Stritch School of Medicine, Loyola University Chicago, Maywood, IL, USA
- Phymedexp INSERM, CNRS, University of Montpellier , Montpellier, France
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5
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Moulton MJ, Secomb TW. A fast computational model for circulatory dynamics: effects of left ventricle-aorta coupling. Biomech Model Mechanobiol 2023; 22:947-959. [PMID: 36639560 PMCID: PMC10167185 DOI: 10.1007/s10237-023-01690-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Accepted: 01/05/2023] [Indexed: 01/15/2023]
Abstract
The course of diseases such as hypertension, systolic heart failure and heart failure with a preserved ejection fraction is affected by interactions between the left ventricle (LV) and the vasculature. To study these interactions, a computationally efficient, biophysically based mathematical model for the circulatory system is presented. In a four-chamber model of the heart, the LV is represented by a previously described low-order, wall volume-preserving model that includes torsion and base-to-apex and circumferential wall shortening and lengthening, and the other chambers are represented using spherical geometries. Active and passive myocardial mechanics of all four chambers are included. The cardiac model is coupled with a wave propagation model for the aorta and a closed lumped-parameter circulation model. Parameters for the normal heart and aorta are determined by fitting to experimental data. Changes in the timing and magnitude of pulse wave reflections by the aorta are demonstrated with changes in compliance and taper of the aorta as seen in aging (decreased compliance, increased diameter and length), and resulting effects on LV pressure-volume loops and LV fiber stress and sarcomere shortening are predicted. Effects of aging of the aorta combined with reduced LV contractile force (failing heart) are examined. In the failing heart, changes in aortic properties with aging affect stroke volume and sarcomere shortening without appreciable augmentation of aortic pressure, and the reflected pressure wave contributes an increased proportion of aortic pressure.
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Affiliation(s)
- Michael J Moulton
- Department of Surgery, Cardiothoracic Surgery, University of Nebraska Medical Center, 982315 Nebraska Medical Center, Omaha, NE, 68198, USA.
| | - Timothy W Secomb
- Program in Applied Mathematics, University of Arizona, Tucson, AZ, 85724, USA
- Department of Physiology, University of Arizona, Tucson, AZ, 85724, USA
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6
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Szőke K, Bódi B, Hendrik Z, Czompa A, Gyöngyösi A, Haines DD, Papp Z, Tósaki Á, Lekli I. Rapamycin treatment increases survival, autophagy biomarkers and expression of the anti-aging klotho protein in elderly mice. Pharmacol Res Perspect 2023; 11:e01091. [PMID: 37190667 DOI: 10.1002/prp2.1091] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Accepted: 04/02/2023] [Indexed: 05/17/2023] Open
Abstract
Previous investigations have demonstrated that treatment of animals with rapamycin increases levels of autophagy, which is a process by which cells degrade intracellular detritus, thus suppressing the emergence of senescent cells, whose pro-inflammatory properties, are primary drivers of age-associated physical decline. A hypothesis is tested here that rapamycin treatment of mice approaching the end of their normal lifespan exhibits increased survival, enhanced expression of autophagic proteins; and klotho protein-a biomarker of aging that affects whole organism senescence, and systemic suppression of inflammatory mediator production. Test groups of 24-month-old C57BL mice were injected intraperitoneally with either 1.5 mg/kg/week rapamycin or vehicle. All mice administered rapamycin survived the 12-week course, whereas 43% of the controls died. Relative to controls, rapamycin-treated mice experienced minor but significant weight loss; moreover, nonsignificant trends toward decreased levels of leptin, IL-6, IL-1β, TNF-α, IL-1α, and IGF-1, along with slight elevations in VEGF, MCP-1 were observed in the blood serum of rapamycin-treated mice. Rapamycin-treated mice exhibited significantly enhanced autophagy and elevated expression of klotho protein, particularly in the kidney. Rapamycin treatment also increased cardiomyocyte Ca2+ -sensitivity and enhanced the rate constant of force re-development, which may also contribute to the enhanced survival rate in elderly mice.
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Affiliation(s)
- Kitti Szőke
- Department of Pharmacology, Faculty of Pharmacy, University of Debrecen, Debrecen, Hungary
| | - Beáta Bódi
- Division of Clinical Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Zoltán Hendrik
- Institute of Forensic Medicine, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Attila Czompa
- Department of Pharmacology, Faculty of Pharmacy, University of Debrecen, Debrecen, Hungary
| | - Alexandra Gyöngyösi
- Department of Pharmacology, Faculty of Pharmacy, University of Debrecen, Debrecen, Hungary
- Institute of Healthcare Industry, University of Debrecen, Debrecen, Hungary
| | | | - Zoltán Papp
- Division of Clinical Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
- HAS-UD Vascular Biology and Myocardial Pathophysiology Research Group, Hungarian Academy of Sciences, Budapest, Hungary
| | - Árpád Tósaki
- Department of Pharmacology, Faculty of Pharmacy, University of Debrecen, Debrecen, Hungary
- ELKH-DE Pharmamodul Research Team, University of Debrecen, Debrecen, Hungary
| | - István Lekli
- Department of Pharmacology, Faculty of Pharmacy, University of Debrecen, Debrecen, Hungary
- Institute of Healthcare Industry, University of Debrecen, Debrecen, Hungary
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7
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Cardiac Magnetic Resonance Imaging in Appraising Myocardial Strain and Biomechanics: A Current Overview. Diagnostics (Basel) 2023; 13:diagnostics13030553. [PMID: 36766658 PMCID: PMC9914753 DOI: 10.3390/diagnostics13030553] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Revised: 01/30/2023] [Accepted: 01/31/2023] [Indexed: 02/05/2023] Open
Abstract
Subclinical alterations in myocardial structure and function occur early during the natural disease course. In contrast, clinically overt signs and symptoms occur during late phases, being associated with worse outcomes. Identification of such subclinical changes is critical for timely diagnosis and accurate management. Hence, implementing cost-effective imaging techniques with accuracy and reproducibility may improve long-term prognosis. A growing body of evidence supports using cardiac magnetic resonance (CMR) to quantify deformation parameters. Tissue-tagging (TT-CMR) and feature-tracking CMR (FT-CMR) can measure longitudinal, circumferential, and radial strains and recent research emphasize their diagnostic and prognostic roles in ischemic heart disease and primary myocardial illnesses. Additionally, these methods can accurately determine LV wringing and functional dynamic geometry parameters, such as LV torsion, twist/untwist, LV sphericity index, and long-axis strain, and several studies have proved their utility in prognostic prediction in various cardiovascular patients. More recently, few yet important studies have suggested the superiority of fast strain-encoded imaging CMR-derived myocardial strain in terms of accuracy and significantly reduced acquisition time, however, more studies need to be carried out to establish its clinical impact. Herein, the current review aims to provide an overview of currently available data regarding the role of CMR in evaluating myocardial strain and biomechanics.
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8
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Miller JM, Meki MH, Elnakib A, Ou Q, Abouleisa RRE, Tang XL, Salama ABM, Gebreil A, Lin C, Abdeltawab H, Khalifa F, Hill BG, Abi-Gerges N, Bolli R, El-Baz AS, Giridharan GA, Mohamed TMA. Biomimetic cardiac tissue culture model (CTCM) to emulate cardiac physiology and pathophysiology ex vivo. Commun Biol 2022; 5:934. [PMID: 36085302 PMCID: PMC9463130 DOI: 10.1038/s42003-022-03919-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Accepted: 08/30/2022] [Indexed: 11/23/2022] Open
Abstract
There is need for a reliable in vitro system that can accurately replicate the cardiac physiological environment for drug testing. The limited availability of human heart tissue culture systems has led to inaccurate interpretations of cardiac-related drug effects. Here, we developed a cardiac tissue culture model (CTCM) that can electro-mechanically stimulate heart slices with physiological stretches in systole and diastole during the cardiac cycle. After 12 days in culture, this approach partially improved the viability of heart slices but did not completely maintain their structural integrity. Therefore, following small molecule screening, we found that the incorporation of 100 nM tri-iodothyronine (T3) and 1 μM dexamethasone (Dex) into our culture media preserved the microscopic structure of the slices for 12 days. When combined with T3/Dex treatment, the CTCM system maintained the transcriptional profile, viability, metabolic activity, and structural integrity for 12 days at the same levels as the fresh heart tissue. Furthermore, overstretching the cardiac tissue induced cardiac hypertrophic signaling in culture, which provides a proof of concept for the ability of the CTCM to emulate cardiac stretch-induced hypertrophic conditions. In conclusion, CTCM can emulate cardiac physiology and pathophysiology in culture for an extended time, thereby enabling reliable drug screening.
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Affiliation(s)
- Jessica M Miller
- From the Institute of Molecular Cardiology, Department of Medicine, University of Louisville, Louisville, USA
- Department of Bioengineering, University of Louisville, Louisville, USA
| | - Moustafa H Meki
- From the Institute of Molecular Cardiology, Department of Medicine, University of Louisville, Louisville, USA
- Department of Bioengineering, University of Louisville, Louisville, USA
| | - Ahmed Elnakib
- Department of Bioengineering, University of Louisville, Louisville, USA
| | - Qinghui Ou
- From the Institute of Molecular Cardiology, Department of Medicine, University of Louisville, Louisville, USA
| | - Riham R E Abouleisa
- From the Institute of Molecular Cardiology, Department of Medicine, University of Louisville, Louisville, USA
| | - Xian-Liang Tang
- From the Institute of Molecular Cardiology, Department of Medicine, University of Louisville, Louisville, USA
| | - Abou Bakr M Salama
- From the Institute of Molecular Cardiology, Department of Medicine, University of Louisville, Louisville, USA
- Faculty of Medicine, Zagazig University, Zagazig, Egypt
| | - Ahmad Gebreil
- From the Institute of Molecular Cardiology, Department of Medicine, University of Louisville, Louisville, USA
| | - Cindy Lin
- From the Institute of Molecular Cardiology, Department of Medicine, University of Louisville, Louisville, USA
| | - Hisham Abdeltawab
- Department of Bioengineering, University of Louisville, Louisville, USA
| | - Fahmi Khalifa
- Department of Bioengineering, University of Louisville, Louisville, USA
| | - Bradford G Hill
- Envirome Institute, Diabetes and Obesity Center, Department of Medicine, University of Louisville, Louisville, USA
| | | | - Roberto Bolli
- From the Institute of Molecular Cardiology, Department of Medicine, University of Louisville, Louisville, USA
| | - Ayman S El-Baz
- Department of Bioengineering, University of Louisville, Louisville, USA
| | | | - Tamer M A Mohamed
- From the Institute of Molecular Cardiology, Department of Medicine, University of Louisville, Louisville, USA.
- Department of Bioengineering, University of Louisville, Louisville, USA.
- Envirome Institute, Diabetes and Obesity Center, Department of Medicine, University of Louisville, Louisville, USA.
- Department of Pharmacology and Toxicology, University of Louisville, Louisville, USA.
- Institute of Cardiovascular Sciences, University of Manchester, Manchester, United Kingdom.
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9
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Alpha and beta myosin isoforms and human atrial and ventricular contraction. Cell Mol Life Sci 2021; 78:7309-7337. [PMID: 34704115 PMCID: PMC8629898 DOI: 10.1007/s00018-021-03971-y] [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: 04/21/2021] [Revised: 10/03/2021] [Accepted: 10/08/2021] [Indexed: 01/15/2023]
Abstract
Human atrial and ventricular contractions have distinct mechanical characteristics including speed of contraction, volume of blood delivered and the range of pressure generated. Notably, the ventricle expresses predominantly β-cardiac myosin while the atrium expresses mostly the α-isoform. In recent years exploration of the properties of pure α- & β-myosin isoforms have been possible in solution, in isolated myocytes and myofibrils. This allows us to consider the extent to which the atrial vs ventricular mechanical characteristics are defined by the myosin isoform expressed, and how the isoform properties are matched to their physiological roles. To do this we Outline the essential feature of atrial and ventricular contraction; Explore the molecular structural and functional characteristics of the two myosin isoforms; Describe the contractile behaviour of myocytes and myofibrils expressing a single myosin isoform; Finally we outline the outstanding problems in defining the differences between the atria and ventricles. This allowed us consider what features of contraction can and cannot be ascribed to the myosin isoforms present in the atria and ventricles.
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10
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Muir WW, Hamlin RL. Myocardial Contractility: Historical and Contemporary Considerations. Front Physiol 2020; 11:222. [PMID: 32296340 PMCID: PMC7137917 DOI: 10.3389/fphys.2020.00222] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Accepted: 02/26/2020] [Indexed: 12/17/2022] Open
Abstract
The term myocardial contractility is thought to have originated more than 125 years ago and has remained and enigma ever since. Although the term is frequently used in textbooks, editorials and contemporary manuscripts its definition remains illusive often being conflated with cardiac performance or inotropy. The absence of a universally accepted definition has led to confusion, disagreement and misconceptions among physiologists, cardiologists and safety pharmacologists regarding its definition particularly in light of new discoveries regarding the load dependent kinetics of cardiac contraction and their translation to cardiac force-velocity and ventricular pressure-volume measurements. Importantly, the Starling interpretation of force development is length-dependent while contractility is length independent. Most historical definitions employ an operational approach and define cardiac contractility in terms of the hearts mechanical properties independent of loading conditions. Literally defined the term contract infers that something has become smaller, shrunk or shortened. The addition of the suffix “ility” implies the quality of this process. The discovery and clinical investigation of small molecules that bind to sarcomeric proteins independently altering force or velocity requires that a modern definition of the term myocardial contractility be developed if the term is to persist. This review reconsiders the historical and contemporary interpretations of the terms cardiac performance and inotropy and recommends a modern definition of myocardial contractility as the preload, afterload and length-independent intrinsic kinetically controlled, chemo-mechanical processes responsible for the development of force and velocity.
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Affiliation(s)
- William W Muir
- College of Veterinary Medicine, Lincoln Memorial University, Harrogate, TN, United States
| | - Robert L Hamlin
- College of Veterinary Medicine, The Ohio State University, Columbus, OH, United States
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11
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Cardiac adaptation in hibernating, free-ranging Scandinavian Brown Bears (Ursus arctos). Sci Rep 2020; 10:247. [PMID: 31937799 PMCID: PMC6959366 DOI: 10.1038/s41598-019-57126-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Accepted: 12/09/2019] [Indexed: 11/23/2022] Open
Abstract
During six months of annual hibernation, the brown bear undergoes unique physiological changes to adapt to decreased metabolic rate. We compared cardiac structural and functional measures of hibernating and active bears using comprehensive echocardiography. We performed echocardiography on 13 subadult free-ranging, anaesthetised Scandinavian brown bears (Ursus arctos) during late hibernation and in early summer. Mean heart rate was 26 beats per minute (standard deviation (SD): 8) during hibernation vs 71 (SD: 14) during active state. All left ventricular (LV) systolic and diastolic measures were decreased during hibernation: mean ejection fraction: 44.2% (SD: 6.0) active state vs 34.0 (SD: 8.1) hibernation, P = 0.001; global longitudinal strain: −11.2% (SD: 2.0) vs −8.8 (SD: 3.3), P = 0.03; global longitudinal strain rate: −0.82 (SD: 0.15) vs −0.41 (SD: 0.18), P < 0.001; septal e’: 9.8 cm/s (SD: 1.8) vs 5.2 (SD: 2.7), P < 0.001. In general, measures of total myocardial motion (ejection fraction and global longitudinal strain) were decreased to a lesser extent than measures of myocardial velocities. In the hibernating brown bear, cardiac adaptation included decreased functional measures, primarily measures of myocardial velocities, but was not associated with cardiac atrophy. Understanding the mechanisms of these adaptations could provide pathophysiological insight of human pathological conditions such as heart failure.
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Tomalka A, Röhrle O, Han JC, Pham T, Taberner AJ, Siebert T. Extensive eccentric contractions in intact cardiac trabeculae: revealing compelling differences in contractile behaviour compared to skeletal muscles. Proc Biol Sci 2019; 286:20190719. [PMID: 31138072 DOI: 10.1098/rspb.2019.0719] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Force enhancement (FE) is a phenomenon that is present in skeletal muscle. It is characterized by progressive forces upon active stretching-distinguished by a linear rise in force-and enhanced isometric force following stretching (residual FE (RFE)). In skeletal muscle, non-cross-bridge (XB) structures may account for this behaviour. So far, it is unknown whether differences between non-XB structures within the heart and skeletal muscle result in deviating contractile behaviour during and after eccentric contractions. Thus, we investigated the force response of intact cardiac trabeculae during and after isokinetic eccentric muscle contractions (10% of maximum shortening velocity) with extensive magnitudes of stretch (25% of optimum muscle length). The different contributions of XB and non-XB structures to the total muscle force were revealed by using an actomyosin inhibitor. For cardiac trabeculae, we found that the force-length dynamics during long stretch were similar to the total isometric force-length relation. This indicates that no (R)FE is present in cardiac muscle while stretching the muscle from 0.75 to 1.0 optimum muscle length. This finding is in contrast with the results obtained for skeletal muscle, in which (R)FE is present. Our data support the hypothesis that titin stiffness does not increase with activation in cardiac muscle.
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Affiliation(s)
- André Tomalka
- 1 Department of Motion and Exercise Science, University of Stuttgart , Stuttgart , Germany
| | - Oliver Röhrle
- 2 Institute of Applied Mechanics (Civil Engineering), University of Stuttgart , Stuttgart , Germany.,3 Cluster of Excellence for Simulation Technology (SimTech) , Stuttgart , Germany
| | - June-Chiew Han
- 4 Auckland Bioengineering Institute, The University of Auckland , Auckland , New Zealand
| | - Toan Pham
- 5 Department of Physiology, The University of Auckland , Auckland , New Zealand
| | - Andrew J Taberner
- 4 Auckland Bioengineering Institute, The University of Auckland , Auckland , New Zealand.,6 Department of Engineering Science, The University of Auckland , Auckland , New Zealand
| | - Tobias Siebert
- 1 Department of Motion and Exercise Science, University of Stuttgart , Stuttgart , Germany
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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: 67] [Impact Index Per Article: 13.4] [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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Pingel J, Suhr F. Are mechanically sensitive regulators involved in the function and (patho)physiology of cerebral palsy-related contractures? J Muscle Res Cell Motil 2017; 38:317-330. [PMID: 29190010 DOI: 10.1007/s10974-017-9489-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Accepted: 11/21/2017] [Indexed: 12/17/2022]
Abstract
Skeletal muscle tissue is mechanosensitive, as it is able to sense mechanical impacts and to translate these into biochemical signals making the tissue adapt. Among its mechanosensitive nature, skeletal muscle tissue is the largest metabolic organ of the human body. Disturbances in skeletal muscle mechanosensing and metabolism cause and contribute to many diseases, i.e. muscular dystrophies/myopathies, cardiovascular diseases, COPD or diabetes mellitus type 2. A less commonly focused muscle-related disorder is clinically known as muscle contractures that derive from cerebral palsy (CP) conditions in young and adults. Muscle contractures are characterized by gradually increasing passive muscle stiffness resulting in complete fixation of joints. Different mechanisms have been identified in CP-related contractures, i.e. altered calcium handling, altered metabolism or altered titin regulation. The muscle-related extracellular matrix (ECM), specifically collagens, plays a role in CP-related contractures. Herein, we focus on mechanically sensitive complexes, known as costameres (Cstms), and discuss their potential role in CP-related contractures. We extend our discussion to the ECM due to the limited knowledge of its role in CP-related contractures. The aims of this review are (1) to summarize CP-related contracture mechanisms, (2) to raise novel hypotheses on the genesis of contractures with a focus on Cstms, and (3) to stimulate novel approaches to study CP-related contractures.
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Affiliation(s)
- Jessica Pingel
- Motor Control Lab, Department of Neuroscience and Pharmacology, University of Copenhagen, Blegdamsvej 3b, 2200, Copenhagen N, Denmark.
| | - Frank Suhr
- Exercise Physiology Research Group, Department of Movement Sciences, Biomedical Sciences Group, KU Leuven, Tervuursevest 101, box 1500, 3001, Leuven, Belgium.
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Meng T, Bu W, Ren X, Chen X, Yu J, Eckenhoff RG, Gao WD. Molecular mechanism of anesthetic-induced depression of myocardial contraction. FASEB J 2016; 30:2915-25. [PMID: 27170289 DOI: 10.1096/fj.201600290rr] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Accepted: 04/26/2016] [Indexed: 01/22/2023]
Abstract
Isoflurane and propofol are known to depress cardiac contraction, but the molecular mechanisms involved are not known. In this study, we determined whether decreasing myofilament Ca(2+) responsiveness underlies anesthesia-induced depression of contraction and uncovered the molecular targets of isoflurane and propofol. Force and intracellular Ca(2+) ([Ca(2+)]i) were measured in rat trabeculae superfused with Krebs-Henseleit solution, with or without propofol or isoflurane. Photoaffinity labeling of myofilament proteins with meta-Azi-propofol (AziPm) and Azi-isoflurane (Azi-iso) and molecular docking were also used. Both propofol and isoflurane dose dependently depressed force from low doses (propofol, 27 ± 6 μM; isoflurane, 1.0 ± 0.1%) to moderate doses (propofol, 87 ± 4 μM; isoflurane, 3.0 ± 0.25%), without significant alteration [Ca(2+)]i During steady-state activations in both intact and skinned preparations, propofol and isoflurane depressed maximum Ca(2+)-activated force and increased the [Ca(2+)]i required for 50% of activation. Myofibrils photolabeled with AziPm and Azi-iso identified myosin, actin, and myosin light chain as targets of the anesthetics. Several adducted residues in those proteins were located in conformationally sensitive regions that underlie contractile function. Thus, propofol and isoflurane decrease force development by directly depressing myofilament Ca(2+) responsiveness and have binding sites in key regions for contraction in both actin and myosin.-Meng, T., Bu, W., Ren, X., Chen, X., Yu, J., Eckenhoff, R. G., Gao, W. D. Molecular mechanism of anesthetic-induced depression of myocardial contraction.
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Affiliation(s)
- Tao Meng
- Department of Anesthesiology, Qilu Hospital of Shandong University, Jinan, Shandong, China
| | - Weiming Bu
- Department of Anesthesiology and Critical Care, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Xianfeng Ren
- Department of Anesthesiology, China-Japan Friendship Hospital, Beijing, China
| | - Xinzhong Chen
- Department of Cardiac Surgery, Tongji University Medical Center, Wuhan, China; and
| | - Jingui Yu
- Department of Anesthesiology, Qilu Hospital of Shandong University, Jinan, Shandong, China
| | - Roderic G Eckenhoff
- Department of Anesthesiology and Critical Care, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA;
| | - Wei Dong Gao
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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Contractility of single cardiomyocytes differentiated from pluripotent stem cells depends on physiological shape and substrate stiffness. Proc Natl Acad Sci U S A 2015; 112:12705-10. [PMID: 26417073 DOI: 10.1073/pnas.1508073112] [Citation(s) in RCA: 331] [Impact Index Per Article: 36.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Single cardiomyocytes contain myofibrils that harbor the sarcomere-based contractile machinery of the myocardium. Cardiomyocytes differentiated from human pluripotent stem cells (hPSC-CMs) have potential as an in vitro model of heart activity. However, their fetal-like misalignment of myofibrils limits their usefulness for modeling contractile activity. We analyzed the effects of cell shape and substrate stiffness on the shortening and movement of labeled sarcomeres and the translation of sarcomere activity to mechanical output (contractility) in live engineered hPSC-CMs. Single hPSC-CMs were cultured on polyacrylamide substrates of physiological stiffness (10 kPa), and Matrigel micropatterns were used to generate physiological shapes (2,000-µm(2) rectangles with length:width aspect ratios of 5:1-7:1) and a mature alignment of myofibrils. Translation of sarcomere shortening to mechanical output was highest in 7:1 hPSC-CMs. Increased substrate stiffness and applied overstretch induced myofibril defects in 7:1 hPSC-CMs and decreased mechanical output. Inhibitors of nonmuscle myosin activity repressed the assembly of myofibrils, showing that subcellular tension drives the improved contractile activity in these engineered hPSC-CMs. Other factors associated with improved contractility were axially directed calcium flow, systematic mitochondrial distribution, more mature electrophysiology, and evidence of transverse-tubule formation. These findings support the potential of these engineered hPSC-CMs as powerful models for studying myocardial contractility at the cellular level.
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Abstract
The heart pumps blood to maintain circulation and ensure the delivery of oxygenated blood to all the organs of the body. Mechanics play a critical role in governing and regulating heart function under both normal and pathological conditions. Biological processes and mechanical stress are coupled together in regulating myocyte function and extracellular matrix structure thus controlling heart function. Here, we offer a brief introduction to the biomechanics of left ventricular function and then summarize recent progress in the study of the effects of mechanical stress on ventricular wall remodeling and cardiac function as well as the effects of wall mechanical properties on cardiac function in normal and dysfunctional hearts. Various mechanical models to determine wall stress and cardiac function in normal and diseased hearts with both systolic and diastolic dysfunction are discussed. The results of these studies have enhanced our understanding of the biomechanical mechanism in the development and remodeling of normal and dysfunctional hearts. Biomechanics provide a tool to understand the mechanism of left ventricular remodeling in diastolic and systolic dysfunction and guidance in designing and developing new treatments.
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Affiliation(s)
- Andrew P. Voorhees
- Department of Mechanical Engineering, The University of Texas at San Antonio, Biomedical Engineering Program, UTSA-UTHSCSA
| | - Hai-Chao Han
- Department of Mechanical Engineering, The University of Texas at San Antonio, Biomedical Engineering Program, UTSA-UTHSCSA
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