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Nag S, Gollapudi SK, Del Rio CL, Spudich JA, McDowell R. Mavacamten, a precision medicine for hypertrophic cardiomyopathy: From a motor protein to patients. SCIENCE ADVANCES 2023; 9:eabo7622. [PMID: 37506209 DOI: 10.1126/sciadv.abo7622] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Accepted: 06/23/2023] [Indexed: 07/30/2023]
Abstract
Hypertrophic cardiomyopathy (HCM) is a primary myocardial disorder characterized by left ventricular hypertrophy, hyperdynamic contraction, and impaired relaxation of the heart. These functional derangements arise directly from altered sarcomeric function due to either mutations in genes encoding sarcomere proteins, or other defects such as abnormal energetics. Current treatment options do not directly address this causal biology but focus on surgical and extra-sarcomeric (sarcolemmal) pharmacological symptomatic relief. Mavacamten (formerly known as MYK-461), is a small molecule designed to regulate cardiac function at the sarcomere level by selectively but reversibly inhibiting the enzymatic activity of myosin, the fundamental motor of the sarcomere. This review summarizes the mechanism and translational progress of mavacamten from proteins to patients, describing how the mechanism of action and pharmacological characteristics, involving both systolic and diastolic effects, can directly target pathophysiological derangements within the cardiac sarcomere to improve cardiac structure and function in HCM. Mavacamten was approved by the Food and Drug Administration in April 2022 for the treatment of obstructive HCM and now goes by the commercial name of Camzyos. Full information about the risks, limitations, and side effects can be found at www.accessdata.fda.gov/drugsatfda_docs/label/2022/214998s000lbl.pdf.
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Affiliation(s)
- Suman Nag
- MyoKardia Inc., a wholly owned subsidiary of Bristol Myers Squibb, Brisbane, CA 94005, USA
| | - Sampath K Gollapudi
- MyoKardia Inc., a wholly owned subsidiary of Bristol Myers Squibb, Brisbane, CA 94005, USA
| | - Carlos L Del Rio
- MyoKardia Inc., a wholly owned subsidiary of Bristol Myers Squibb, Brisbane, CA 94005, USA
- Cardiac Consulting, 1630 S Delaware St. #56426, San Mateo, CA 94403, USA
| | | | - Robert McDowell
- MyoKardia Inc., a wholly owned subsidiary of Bristol Myers Squibb, Brisbane, CA 94005, USA
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Zabielska-Kaczorowska MA, Smolenski RT. Nucleotide metabolism during experimental preservation for transplantation with Transmedium Transplant Fluid (TTF) in comparison to Histidine-Tryptophan-Ketoglutarate (HTK). NUCLEOSIDES, NUCLEOTIDES & NUCLEIC ACIDS 2022; 41:1386-1395. [PMID: 36323286 DOI: 10.1080/15257770.2022.2139393] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Organ preservation solutions are essential to diminish ischemic/hypoxic injury during cold storage and to improve graft survival. In our experiments, we investigated novel solutions that target such mechanisms as Transmedium Transplant Fluid (TTF) in comparison to PlegiStore solution (HTK). Rat hearts were infused with TTF or HTK and then subjected to 4 hours of 4 °C preservation followed by 25 minutes of reperfusion in the Langendorff system. Assessment of purine release from the heart, mechanical function, and cardiac nucleotide content in the heart homogenates was done. A significant increase in the uric acid, hypoxanthine, inosine, and total purine metabolite concentrations were observed in the HTK hearts when compared to TTF. The TTF group had lower left ventricular systolic pressure and left ventricular end-diastolic pressure when compared to the HTK. Left ventricular diastolic pressure, minimal dp/dt, and maximal dp/dt in both groups were similar. The concentration of ADP in the heart homogenates of the HTK group was increased when compared to the TTF group. ATP and GTP concentration showed a tendency to increase in the homogenates of TTF hearts when NAD, AMP, GDP, GMP, and ADPR were similar in both groups of rats. TTF provided enhanced cardioprotection as evidenced by inhibiting the purine nucleotide metabolites released from the rat hearts during reperfusion and enhanced systolic and diastolic mechanical function recovery. In particular, better preservation of GTP and ATP concentrations may translate into enhanced protection of endothelium and the cytoskeleton, which are not adequately protected with current preservation techniques.
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Affiliation(s)
- Magdalena A Zabielska-Kaczorowska
- Department of Biochemistry, Medical University of Gdansk, Gdansk, Poland.,Department of Physiology, Medical University of Gdansk, Gdansk, Poland
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3
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Sikorski V, Vento A, Kankuri E. Emerging roles of the RNA modifications N6-methyladenosine and adenosine-to-inosine in cardiovascular diseases. MOLECULAR THERAPY - NUCLEIC ACIDS 2022; 29:426-461. [PMID: 35991314 PMCID: PMC9366019 DOI: 10.1016/j.omtn.2022.07.018] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Cardiovascular diseases lead the mortality and morbidity disease metrics worldwide. A multitude of chemical base modifications in ribonucleic acids (RNAs) have been linked with key events of cardiovascular diseases and metabolic disorders. Named either RNA epigenetics or epitranscriptomics, the post-transcriptional RNA modifications, their regulatory pathways, components, and downstream effects substantially contribute to the ways our genetic code is interpreted. Here we review the accumulated discoveries to date regarding the roles of the two most common epitranscriptomic modifications, N6-methyl-adenosine (m6A) and adenosine-to-inosine (A-to-I) editing, in cardiovascular disease.
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Affiliation(s)
- Vilbert Sikorski
- Department of Pharmacology, Faculty of Medicine, University of Helsinki, 00014 Helsinki, Finland
| | - Antti Vento
- Heart and Lung Center, Helsinki University Hospital, 00029 Helsinki, Finland
| | - Esko Kankuri
- Department of Pharmacology, Faculty of Medicine, University of Helsinki, 00014 Helsinki, Finland
- Corresponding author Esko Kankuri, M.D. Ph.D., Faculty of Medicine, Department of Pharmacology, PO Box 63 (Haartmaninkatu 8), FIN-00014 University of Helsinki, 00014 Helsinki, Finland.
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Stachowski-Doll MJ, Papadaki M, Martin TG, Ma W, Gong HM, Shao S, Shen S, Muntu NA, Kumar M, Perez E, Martin JL, Moravec CS, Sadayappan S, Campbell SG, Irving T, Kirk JA. GSK-3β Localizes to the Cardiac Z-Disc to Maintain Length Dependent Activation. Circ Res 2022; 130:871-886. [PMID: 35168370 PMCID: PMC8930626 DOI: 10.1161/circresaha.121.319491] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Altered kinase localization is gaining appreciation as a mechanism of cardiovascular disease. Previous work suggests GSK-3β (glycogen synthase kinase 3β) localizes to and regulates contractile function of the myofilament. We aimed to discover GSK-3β's in vivo role in regulating myofilament function, the mechanisms involved, and the translational relevance. METHODS Inducible cardiomyocyte-specific GSK-3β knockout mice and left ventricular myocardium from nonfailing and failing human hearts were studied. RESULTS Skinned cardiomyocytes from knockout mice failed to exhibit calcium sensitization with stretch indicating a loss of length-dependent activation (LDA), the mechanism underlying the Frank-Starling Law. Titin acts as a length sensor for LDA, and knockout mice had decreased titin stiffness compared with control mice, explaining the lack of LDA. Knockout mice exhibited no changes in titin isoforms, titin phosphorylation, or other thin filament phosphorylation sites known to affect passive tension or LDA. Mass spectrometry identified several z-disc proteins as myofilament phospho-substrates of GSK-3β. Agreeing with the localization of its targets, GSK-3β that is phosphorylated at Y216 binds to the z-disc. We showed pY216 was necessary and sufficient for z-disc binding using adenoviruses for wild-type, Y216F, and Y216E GSK-3β in neonatal rat ventricular cardiomyocytes. One of GSK-3β's z-disc targets, abLIM-1 (actin-binding LIM protein 1), binds to the z-disc domains of titin that are important for maintaining passive tension. Genetic knockdown of abLIM-1 via siRNA in human engineered heart tissues resulted in enhancement of LDA, indicating abLIM-1 may act as a negative regulator that is modulated by GSK-3β. Last, GSK-3β myofilament localization was reduced in left ventricular myocardium from failing human hearts, which correlated with depressed LDA. CONCLUSIONS We identified a novel mechanism by which GSK-3β localizes to the myofilament to modulate LDA. Importantly, z-disc GSK-3β levels were reduced in patients with heart failure, indicating z-disc localized GSK-3β is a possible therapeutic target to restore the Frank-Starling mechanism in patients with heart failure.
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Affiliation(s)
- Marisa J Stachowski-Doll
- Department of Cell and Molecular Physiology, Loyola University Stritch School of Medicine, Maywood, IL (M.J.S.-D., M.P., T.G.M., N.A.M., E.P., J.A.K.)
| | - Maria Papadaki
- Department of Cell and Molecular Physiology, Loyola University Stritch School of Medicine, Maywood, IL (M.J.S.-D., M.P., T.G.M., N.A.M., E.P., J.A.K.)
| | - Thomas G Martin
- Department of Cell and Molecular Physiology, Loyola University Stritch School of Medicine, Maywood, IL (M.J.S.-D., M.P., T.G.M., N.A.M., E.P., J.A.K.)
| | - Weikang Ma
- Center for Synchrotron Radiation Research and Instrumentation and Department of Biological Sciences, Illinois Institute of Technology, Chicago (W.M., H.M.G., T.I.)
| | - Henry M Gong
- Center for Synchrotron Radiation Research and Instrumentation and Department of Biological Sciences, Illinois Institute of Technology, Chicago (W.M., H.M.G., T.I.)
| | - Stephanie Shao
- Department of Bioengineering, Yale University, New Haven, CT (S. Shao, S. Shen, S.G.C.)
| | - Shi Shen
- Department of Bioengineering, Yale University, New Haven, CT (S. Shao, S. Shen, S.G.C.)
| | - Nitha Aima Muntu
- Department of Cell and Molecular Physiology, Loyola University Stritch School of Medicine, Maywood, IL (M.J.S.-D., M.P., T.G.M., N.A.M., E.P., J.A.K.)
| | - Mohit Kumar
- Division of Cardiovascular Health and Disease, Department of Internal Medicine, Heart, Lung, and Vascular Institute, University of Cincinnati, OH (M.K., S. Sadayappan)
| | - Edith Perez
- Department of Cell and Molecular Physiology, Loyola University Stritch School of Medicine, Maywood, IL (M.J.S.-D., M.P., T.G.M., N.A.M., E.P., J.A.K.)
| | - Jody L Martin
- Department of Pharmacology, Cardiovascular Research Institute, UC Davis School of Medicine, CA (J.L.M.)
| | - Christine S Moravec
- Department of Cardiovascular and Metabolic Sciences, Cleveland Clinic, OH (C.S.M.)
| | - Sakthivel Sadayappan
- Division of Cardiovascular Health and Disease, Department of Internal Medicine, Heart, Lung, and Vascular Institute, University of Cincinnati, OH (M.K., S. Sadayappan)
| | - Stuart G Campbell
- Department of Bioengineering, Yale University, New Haven, CT (S. Shao, S. Shen, S.G.C.).,Department of Cellular and Molecular Physiology, Yale School of Medicine, New Haven, CT (S.G.C.)
| | - Thomas Irving
- Center for Synchrotron Radiation Research and Instrumentation and Department of Biological Sciences, Illinois Institute of Technology, Chicago (W.M., H.M.G., T.I.)
| | - Jonathan A Kirk
- Department of Cell and Molecular Physiology, Loyola University Stritch School of Medicine, Maywood, IL (M.J.S.-D., M.P., T.G.M., N.A.M., E.P., J.A.K.)
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Alegre-Cebollada J. Protein nanomechanics in biological context. Biophys Rev 2021; 13:435-454. [PMID: 34466164 PMCID: PMC8355295 DOI: 10.1007/s12551-021-00822-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Accepted: 07/05/2021] [Indexed: 12/20/2022] Open
Abstract
How proteins respond to pulling forces, or protein nanomechanics, is a key contributor to the form and function of biological systems. Indeed, the conventional view that proteins are able to diffuse in solution does not apply to the many polypeptides that are anchored to rigid supramolecular structures. These tethered proteins typically have important mechanical roles that enable cells to generate, sense, and transduce mechanical forces. To fully comprehend the interplay between mechanical forces and biology, we must understand how protein nanomechanics emerge in living matter. This endeavor is definitely challenging and only recently has it started to appear tractable. Here, I introduce the main in vitro single-molecule biophysics methods that have been instrumental to investigate protein nanomechanics over the last 2 decades. Then, I present the contemporary view on how mechanical force shapes the free energy of tethered proteins, as well as the effect of biological factors such as post-translational modifications and mutations. To illustrate the contribution of protein nanomechanics to biological function, I review current knowledge on the mechanobiology of selected muscle and cell adhesion proteins including titin, talin, and bacterial pilins. Finally, I discuss emerging methods to modulate protein nanomechanics in living matter, for instance by inducing specific mechanical loss-of-function (mLOF). By interrogating biological systems in a causative manner, these new tools can contribute to further place protein nanomechanics in a biological context.
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Behmer Hansen RA, Wang X, Kaw G, Pierre V, Senyo SE. Accounting for Material Changes in Decellularized Tissue with Underutilized Methodologies. BIOMED RESEARCH INTERNATIONAL 2021; 2021:6696295. [PMID: 34159202 PMCID: PMC8187050 DOI: 10.1155/2021/6696295] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Revised: 05/05/2021] [Accepted: 05/21/2021] [Indexed: 11/17/2022]
Abstract
Tissue decellularization has rapidly developed to be a practical approach in tissue engineering research; biological tissue is cleared of cells resulting in a protein-rich husk as a natural scaffold for growing transplanted cells as a donor organ therapy. Minimally processed, acellular extracellular matrix reproduces natural interactions with cells in vitro and for tissue engineering applications in animal models. There are many decellularization techniques that achieve preservation of molecular profile (proteins and sugars), microstructure features such as organization of ECM layers (interstitial matrix and basement membrane) and organ level macrofeatures (vasculature and tissue compartments). While structural and molecular cues receive attention, mechanical and material properties of decellularized tissues are not often discussed. The effects of decellularization on an organ depend on the tissue properties, clearing mechanism, chemical interactions, solubility, temperature, and treatment duration. Physical characterization by a few labs including work from the authors provides evidence that decellularization protocols should be tailored to specific research questions. Physical characterization beyond histology and immunohistochemistry of the decellularized matrix (dECM) extends evaluation of retained functional features of the original tissue. We direct our attention to current technologies that can be employed for structure function analysis of dECM using underutilized tools such as atomic force microscopy (AFM), cryogenic electron microscopy (cryo-EM), dynamic mechanical analysis (DMA), Fourier-transform infrared spectroscopy (FTIR), mass spectrometry, and rheometry. Structural imaging and mechanical functional testing combined with high-throughput molecular analyses opens a new approach for a deeper appreciation of how cellular behavior is influenced by the isolated microenvironment (specifically dECM). Additionally, the impact of these features with different decellularization techniques and generation of synthetic material scaffolds with desired attributes are informed. Ultimately, this mechanical profiling provides a new dimension to our understanding of decellularized matrix and its role in new applications.
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Affiliation(s)
- Ryan A. Behmer Hansen
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, USA
| | - Xinming Wang
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, USA
| | - Gitanjali Kaw
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, USA
| | - Valinteshley Pierre
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, USA
| | - Samuel E. Senyo
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, USA
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7
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Kit-Anan W, Mazo MM, Wang BX, Leonardo V, Pence IJ, Gopal S, Gelmi A, Nagelkerke A, Becce M, Chiappini C, Harding SE, Terracciano CM, Stevens MM. Multiplexing physical stimulation on single human induced pluripotent stem cell-derived cardiomyocytes for phenotype modulation. Biofabrication 2021; 13:025004. [PMID: 33710972 PMCID: PMC7610872 DOI: 10.1088/1758-5090/abce0a] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Revised: 10/11/2020] [Accepted: 11/25/2020] [Indexed: 12/02/2022]
Abstract
Traditional in vitro bioengineering approaches whereby only individual biophysical cues are manipulated at any one time are highly inefficient, falling short when recapitulating the complexity of the cardiac environment. Multiple biophysical cues are present in the native myocardial niche and are essential during development, as well as in maintenance of adult cardiomyocyte (CM) phenotype in both health and disease. This study establishes a novel biofabrication workflow to study and manipulate hiPSC-CMs and to understand how these cells respond to a multiplexed biophysical environment, namely 3D shape and substrate stiffness, at a single cell level. Silicon masters were fabricated and developed to generate inverse patterns of the desired 3D shapes in bas relief, which then were used to mold the designed microwell arrays into a hydrogel. Polyacrylamide (PAAm) was modified with the incorporation of acrylic acid to provide a carboxylic group conjugation site for adhesion motifs, without compromising capacity to modulate stiffness. In this manner, two individual parameters can be finely tuned independently within the hydrogel: the shape of the 3D microwell and its stiffness. The design allows the platform to isolate single hiPSC-CMs to study solely biophysical cues in the absence of cell-cell physical interaction. Under physiologic-like physical conditions (3D shape resembling that of adult CM and 9.83 kPa substrate stiffness that mimics muscle stiffness), isolated single hiPSC-CMs exhibit increased Cx-43 density, cell membrane stiffness and calcium transient amplitude; co-expression of the subpopulation-related MYL2-MYL7 proteins; and higher anisotropism than cells in pathologic-like conditions (flat surface and 112 kPa substrate stiffness). This demonstrates that supplying a physiologic or pathologic microenvironment to an isolated single hiPSC-CM in the absence of any physical cell-to-cell communication in this biofabricated platform leads to a significantly different set of cellular features, thus presenting a differential phenotype. Importantly, this demonstrates the high plasticity of hiPSC-CMs even in isolation. The ability of multiple biophysical cues to significantly influence isolated single hiPSC-CM phenotype and functionality highlights the importance of fine-tuning such cues for specific applications. This has the potential to produce more fit-for-purpose hiPSC-CMs. Further understanding of human cardiac development is enabled by the robust, versatile and reproducible biofabrication techniques applied here. We envision that this system could be easily applied to other tissues and cell types where the influence of cellular shape and stiffness of the surrounding environment is hypothesized to play an important role in physiology.
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Affiliation(s)
- Worrapong Kit-Anan
- Department of Materials, Imperial College London, London, United Kingdom
- Department of Bioengineering, Imperial College London, London, United Kingdom
- Institute of Biomedical Engineering, Imperial College London, London, United Kingdom
- National Heart and Lung Institute, Imperial College London, London, United Kingdom
| | - Manuel M Mazo
- Department of Materials, Imperial College London, London, United Kingdom
- Department of Bioengineering, Imperial College London, London, United Kingdom
- Institute of Biomedical Engineering, Imperial College London, London, United Kingdom
| | - Brian X Wang
- National Heart and Lung Institute, Imperial College London, London, United Kingdom
| | - Vincent Leonardo
- Department of Materials, Imperial College London, London, United Kingdom
- Department of Bioengineering, Imperial College London, London, United Kingdom
- Institute of Biomedical Engineering, Imperial College London, London, United Kingdom
| | - Isaac J Pence
- Department of Materials, Imperial College London, London, United Kingdom
- Department of Bioengineering, Imperial College London, London, United Kingdom
- Institute of Biomedical Engineering, Imperial College London, London, United Kingdom
| | - Sahana Gopal
- Department of Materials, Imperial College London, London, United Kingdom
- Department of Bioengineering, Imperial College London, London, United Kingdom
- Institute of Biomedical Engineering, Imperial College London, London, United Kingdom
| | - Amy Gelmi
- Department of Materials, Imperial College London, London, United Kingdom
- Department of Bioengineering, Imperial College London, London, United Kingdom
- Institute of Biomedical Engineering, Imperial College London, London, United Kingdom
- Current Address: Applied Chemistry and Environmental Science, School of Science, RMIT University, Melbourne, VIC 3001, Australia
| | - Anika Nagelkerke
- Department of Materials, Imperial College London, London, United Kingdom
- Department of Bioengineering, Imperial College London, London, United Kingdom
- Institute of Biomedical Engineering, Imperial College London, London, United Kingdom
| | - Michele Becce
- Department of Materials, Imperial College London, London, United Kingdom
| | - Ciro Chiappini
- Department of Materials, Imperial College London, London, United Kingdom
- Department of Bioengineering, Imperial College London, London, United Kingdom
- Institute of Biomedical Engineering, Imperial College London, London, United Kingdom
| | - Sian E Harding
- National Heart and Lung Institute, Imperial College London, London, United Kingdom
| | - Cesare M Terracciano
- National Heart and Lung Institute, Imperial College London, London, United Kingdom
| | - Molly M Stevens
- Department of Materials, Imperial College London, London, United Kingdom
- Department of Bioengineering, Imperial College London, London, United Kingdom
- Institute of Biomedical Engineering, Imperial College London, London, United Kingdom
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Montero P, Flandes-Iparraguirre M, Musquiz S, Pérez Araluce M, Plano D, Sanmartín C, Orive G, Gavira JJ, Prosper F, Mazo MM. Cells, Materials, and Fabrication Processes for Cardiac Tissue Engineering. Front Bioeng Biotechnol 2020; 8:955. [PMID: 32850768 PMCID: PMC7431658 DOI: 10.3389/fbioe.2020.00955] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Accepted: 07/23/2020] [Indexed: 12/19/2022] Open
Abstract
Cardiovascular disease is the number one killer worldwide, with myocardial infarction (MI) responsible for approximately 1 in 6 deaths. The lack of endogenous regenerative capacity, added to the deleterious remodelling programme set into motion by myocardial necrosis, turns MI into a progressively debilitating disease, which current pharmacological therapy cannot halt. The advent of Regenerative Therapies over 2 decades ago kick-started a whole new scientific field whose aim was to prevent or even reverse the pathological processes of MI. As a highly dynamic organ, the heart displays a tight association between 3D structure and function, with the non-cellular components, mainly the cardiac extracellular matrix (ECM), playing both fundamental active and passive roles. Tissue engineering aims to reproduce this tissue architecture and function in order to fabricate replicas able to mimic or even substitute damaged organs. Recent advances in cell reprogramming and refinement of methods for additive manufacturing have played a critical role in the development of clinically relevant engineered cardiovascular tissues. This review focuses on the generation of human cardiac tissues for therapy, paying special attention to human pluripotent stem cells and their derivatives. We provide a perspective on progress in regenerative medicine from the early stages of cell therapy to the present day, as well as an overview of cellular processes, materials and fabrication strategies currently under investigation. Finally, we summarise current clinical applications and reflect on the most urgent needs and gaps to be filled for efficient translation to the clinical arena.
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Affiliation(s)
- Pilar Montero
- Regenerative Medicine Program, Cima Universidad de Navarra, Foundation for Applied Medical Research, Pamplona, Spain
| | - María Flandes-Iparraguirre
- Regenerative Medicine Program, Cima Universidad de Navarra, Foundation for Applied Medical Research, Pamplona, Spain
| | - Saioa Musquiz
- Regenerative Medicine Program, Cima Universidad de Navarra, Foundation for Applied Medical Research, Pamplona, Spain
- NanoBioCel Group, Laboratory of Pharmaceutics, School of Pharmacy, University of the Basque Country – UPV/EHU, Vitoria-Gasteiz, Spain
| | - María Pérez Araluce
- Regenerative Medicine Program, Cima Universidad de Navarra, Foundation for Applied Medical Research, Pamplona, Spain
- Department of Pharmaceutical Technology and Chemistry, University of Navarra, Pamplona, Spain
| | - Daniel Plano
- Department of Pharmaceutical Technology and Chemistry, University of Navarra, Pamplona, Spain
- IdiSNA, Navarra Institute for Health Research, Pamplona, Spain
| | - Carmen Sanmartín
- Department of Pharmaceutical Technology and Chemistry, University of Navarra, Pamplona, Spain
- IdiSNA, Navarra Institute for Health Research, Pamplona, Spain
| | - Gorka Orive
- NanoBioCel Group, Laboratory of Pharmaceutics, School of Pharmacy, University of the Basque Country – UPV/EHU, Vitoria-Gasteiz, Spain
- IdiSNA, Navarra Institute for Health Research, Pamplona, Spain
- University Institute for Regenerative Medicine and Oral Implantology – UIRMI (UPV/EHU – Fundación Eduardo Anitua), Vitoria-Gasteiz, Spain
- Singapore Eye Research Institute, Singapore, Singapore
| | - Juan José Gavira
- IdiSNA, Navarra Institute for Health Research, Pamplona, Spain
- Cardiology Department, Clínica Universidad de Navarra, Pamplona, Spain
| | - Felipe Prosper
- Regenerative Medicine Program, Cima Universidad de Navarra, Foundation for Applied Medical Research, Pamplona, Spain
- IdiSNA, Navarra Institute for Health Research, Pamplona, Spain
- Hematology and Cell Therapy Area, Clínica Universidad de Navarra, Pamplona, Spain
| | - Manuel M. Mazo
- Regenerative Medicine Program, Cima Universidad de Navarra, Foundation for Applied Medical Research, Pamplona, Spain
- IdiSNA, Navarra Institute for Health Research, Pamplona, Spain
- Hematology and Cell Therapy Area, Clínica Universidad de Navarra, Pamplona, Spain
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9
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Sack KL, Aliotta E, Choy JS, Ennis DB, Davies NH, Franz T, Kassab GS, Guccione JM. Intra-myocardial alginate hydrogel injection acts as a left ventricular mid-wall constraint in swine. Acta Biomater 2020; 111:170-180. [PMID: 32428678 PMCID: PMC7368390 DOI: 10.1016/j.actbio.2020.04.033] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Revised: 04/09/2020] [Accepted: 04/20/2020] [Indexed: 02/07/2023]
Abstract
Despite positive initial outcomes emerging from preclinical and early clinical investigation of alginate hydrogel injection therapy as a treatment for heart failure, the lack of knowledge about the mechanism of action remains a major shortcoming that limits the efficacy of treatment design. To identify the mechanism of action, we examined previously unobtainable measurements of cardiac function from in vivo, ex vivo, and in silico states of clinically relevant heart failure (HF) in large animals. High-resolution ex vivo magnetic resonance imaging and histological data were used along with state-of-the-art subject-specific computational model simulations. Ex vivo data were incorporated in detailed geometric computational models for swine hearts in health (n = 5), ischemic HF (n = 5), and ischemic HF treated with alginate hydrogel injection therapy (n = 5). Hydrogel injection therapy mitigated elongation of sarcomere lengths (1.68 ± 0.10μm [treated] vs. 1.78 ± 0.15μm [untreated], p<0.001). Systolic contractility in treated animals improved substantially (ejection fraction = 43.9 ± 2.8% [treated] vs. 34.7 ± 2.7% [untreated], p<0.01). The in silico models realistically simulated in vivo function with >99% accuracy and predicted small myofiber strain in the vicinity of the solidified hydrogel that was sustained for up to 13 mm away from the implant. These findings suggest that the solidified alginate hydrogel material acts as an LV mid-wall constraint that significantly reduces adverse LV remodeling compared to untreated HF controls without causing negative secondary outcomes to cardiac function. STATEMENT OF SIGNIFICANCE: Heart failure is considered a growing epidemic and hence an important health problem in the US and worldwide. Its high prevalence (5.8 million and 23 million, respectively) is expected to increase by 25% in the US alone by 2030. Heart failure is associated with high morbidity and mortality, has a 5-year mortality rate of 50%, and contributes considerably to the overall cost of health care ($53.1 billion in the US by 2030). Despite positive initial outcomes emerging from preclinical and early clinical investigation of alginate hydrogel injection therapy as a treatment for heart failure, the lack of knowledge concerning the mechanism of action remains a major shortcoming that limits the efficacy of treatment design. To understand the mechanism of action, we combined high-resolution ex vivo magnetic resonance imaging and histological data in swine with state-of-the-art subject-specific computational model simulations. The in silico models realistically simulated in vivo function with >99% accuracy and predicted small myofiber strain in the vicinity of the solidified hydrogel that was sustained for up to 13 mm away from the implant. These findings suggest that the solidified alginate hydrogel material acts as a left ventricular mid-wall constraint that significantly reduces adverse LV remodeling compared to untreated heart failure controls without causing negative secondary outcomes to cardiac function. Moreover, if the hydrogel can be delivered percutaneously rather than via the currently used open-chest procedure, this therapy may become routine for heart failure treatment. A minimally invasive procedure would be in the best interest of this patient population; i.e., one that cannot tolerate general anesthesia and surgery, and it would be significantly more cost-effective than surgery.
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Affiliation(s)
- Kevin L Sack
- Division of Adult Cardiothoracic Surgery, Department of Surgery, University of California at San Francisco, Box 0118, UC Hall Room U-158, San Francisco, CA, United States; Division of Biomedical Engineering, Department of Human Biology, University of Cape Town, Cape Town, South Africa
| | - Eric Aliotta
- Department of Radiological Sciences, University of California, Los Angeles, California, USA
| | - Jenny S Choy
- California Medical Innovations Institute, Inc., San Diego, California, USA
| | - Daniel B Ennis
- Department of Radiological Sciences, University of California, Los Angeles, California, USA
| | - Neil H Davies
- Cardiovascular Research Unit, Department of Surgery, University of Cape Town, Cape Town, South Africa
| | - Thomas Franz
- Division of Biomedical Engineering, Department of Human Biology, University of Cape Town, Cape Town, South Africa; Bioengineering Science Research Group, Engineering Sciences, Faculty of Engineering and the Environment, University of Southampton, Southampton, UK
| | - Ghassan S Kassab
- California Medical Innovations Institute, Inc., San Diego, California, USA
| | - Julius M Guccione
- Division of Adult Cardiothoracic Surgery, Department of Surgery, University of California at San Francisco, Box 0118, UC Hall Room U-158, San Francisco, CA, United States.
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10
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Izu LT, Kohl P, Boyden PA, Miura M, Banyasz T, Chiamvimonvat N, Trayanova N, Bers DM, Chen-Izu Y. Mechano-electric and mechano-chemo-transduction in cardiomyocytes. J Physiol 2020; 598:1285-1305. [PMID: 31789427 PMCID: PMC7127983 DOI: 10.1113/jp276494] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2019] [Accepted: 11/21/2019] [Indexed: 12/11/2022] Open
Abstract
Cardiac excitation-contraction (E-C) coupling is influenced by (at least) three dynamic systems that couple and feedback to one another (see Abstract Figure). Here we review the mechanical effects on cardiomyocytes that include mechano-electro-transduction (commonly referred to as mechano-electric coupling, MEC) and mechano-chemo-transduction (MCT) mechanisms at cell and molecular levels which couple to Ca2+ -electro and E-C coupling reviewed elsewhere. These feedback loops from muscle contraction and mechano-transduction to the Ca2+ homeodynamics and to the electrical excitation are essential for understanding the E-C coupling dynamic system and arrhythmogenesis in mechanically loaded hearts. This white paper comprises two parts, each reflecting key aspects from the 2018 UC Davis symposium: MEC (how mechanical load influences electrical dynamics) and MCT (how mechanical load alters cell signalling and Ca2+ dynamics). Of course, such separation is artificial since Ca2+ dynamics profoundly affect ion channels and electrogenic transporters and vice versa. In time, these dynamic systems and their interactions must become fully integrated, and that should be a goal for a comprehensive understanding of how mechanical load influences cell signalling, Ca2+ homeodynamics and electrical dynamics. In this white paper we emphasize current understanding, consensus, controversies and the pressing issues for future investigations. Space constraints make it impossible to cover all relevant articles in the field, so we will focus on the topics discussed at the symposium.
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Affiliation(s)
- Leighton T. Izu
- Department of Pharmacology, University of California, Davis, CA 95616, USA
| | - Peter Kohl
- Institute for Experimental Cardiovascular Medicine, University Heart Centre, and Faculty of Medicine, University of Freiburg, D-79110, Germany
| | | | - Masahito Miura
- Department of Clinical Physiology, Health Science, Tohoku University Graduate School of Medicine, Sendai 980-8574, Japan
| | - Tamas Banyasz
- Department of Physiology, University of Debrecen, Debrecen, Hungary
| | - Nipavan Chiamvimonvat
- Department of Internal Medicine, Cardiovascular Medicine, University of California, Davis, USA
| | - Natalia Trayanova
- Department of Department of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Donald M. Bers
- Department of Pharmacology, University of California, Davis, CA 95616, USA
| | - Ye Chen-Izu
- Department of Pharmacology, University of California, Davis, CA 95616, USA
- Department of Internal Medicine, Cardiovascular Medicine, University of California, Davis, USA
- Department of Biomedical Engineering, University of California, Davis, CA 95616, USA
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11
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Hirschvogel M, Jagschies L, Maier A, Wildhirt SM, Gee MW. An in silico twin for epicardial augmentation of the failing heart. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2019; 35:e3233. [PMID: 31267697 DOI: 10.1002/cnm.3233] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Revised: 06/25/2019] [Accepted: 06/25/2019] [Indexed: 06/09/2023]
Abstract
Advances in ventricular assist device (VAD) technology for the treatment of end-stage congestive heart failure (CHF) are needed to cope with the increasing numbers of patients that cannot be provided with donor hearts for transplantation. We develop and investigate a novel extravascular VAD technology that provides biventricular, epicardial pressure support for the failing heart. This novel VAD concept avoids blood contact that is accompanied with typical complications such as coagulation and infections. To date, in vivo porcine model results with a prototype of the implant exist, further studies to improve the implant's performance and promote its applicability in humans are needed. In this contribution, we present a personalised functional digital twin of the heart, the vascular system, and the novel VAD technology in terms of a calibrated, customized computational model. The calibration procedure is based on patient-specific measurements and is performed by solving an inverse problem. This in silico model is able to (a) confirm in vivo experimental data, (b) predict healthy and pathologic ventricular function, and (c) assess the beneficial impact of the novel VAD concept to a high level of fidelity. The model shows very good agreement with in vivo data and reliably predicts increases in stroke volume and left ventricular pressure with increasing ventricular support. Furthermore, the digital twin allows insight into quantities that are poorly or not at all amenable in any experimental setup. Conclusively, the model's ability to link integral hemodynamic variables to local tissue mechanical deformation makes it a highly valuable tool for the dimensioning of novel VAD technologies and future treatment strategies in heart failure. The presented in silico twin enhances in vivo studies by facilitating the accessibility and increasing the range of quantities of interest. Because of its flexibility in the assessment of design variants and optimization loops, it may substantially contribute to a reduction of the amount of animal experiments in this and similar settings.
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Affiliation(s)
- Marc Hirschvogel
- Mechanics & High Performance Computing Group, Technische Universität München, Parkring 35, 85748, Garching b. München, Germany
| | - Lasse Jagschies
- Mechanics & High Performance Computing Group, Technische Universität München, Parkring 35, 85748, Garching b. München, Germany
| | - Andreas Maier
- AdjuCor GmbH, Neumarkter Str. 18, 81673, München, Germany
| | | | - Michael W Gee
- Mechanics & High Performance Computing Group, Technische Universität München, Parkring 35, 85748, Garching b. München, Germany
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12
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Anderson RL, Trivedi DV, Sarkar SS, Henze M, Ma W, Gong H, Rogers CS, Gorham JM, Wong FL, Morck MM, Seidman JG, Ruppel KM, Irving TC, Cooke R, Green EM, Spudich JA. Deciphering the super relaxed state of human β-cardiac myosin and the mode of action of mavacamten from myosin molecules to muscle fibers. Proc Natl Acad Sci U S A 2018; 115:E8143-E8152. [PMID: 30104387 PMCID: PMC6126717 DOI: 10.1073/pnas.1809540115] [Citation(s) in RCA: 236] [Impact Index Per Article: 39.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Mutations in β-cardiac myosin, the predominant motor protein for human heart contraction, can alter power output and cause cardiomyopathy. However, measurements of the intrinsic force, velocity, and ATPase activity of myosin have not provided a consistent mechanism to link mutations to muscle pathology. An alternative model posits that mutations in myosin affect the stability of a sequestered, super relaxed state (SRX) of the protein with very slow ATP hydrolysis and thereby change the number of myosin heads accessible to actin. Here we show that purified human β-cardiac myosin exists partly in an SRX and may in part correspond to a folded-back conformation of myosin heads observed in muscle fibers around the thick filament backbone. Mutations that cause hypertrophic cardiomyopathy destabilize this state, while the small molecule mavacamten promotes it. These findings provide a biochemical and structural link between the genetics and physiology of cardiomyopathy with implications for therapeutic strategies.
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Affiliation(s)
| | - Darshan V Trivedi
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305
| | - Saswata S Sarkar
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305
| | | | - Weikang Ma
- BioCAT, Department of Biological Sciences, Illinois Institute of Technology, Chicago, IL 60616
| | - Henry Gong
- BioCAT, Department of Biological Sciences, Illinois Institute of Technology, Chicago, IL 60616
| | | | - Joshua M Gorham
- Department of Genetics, Harvard Medical School, Boston, MA 02115
| | | | - Makenna M Morck
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305
| | | | - Kathleen M Ruppel
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305
- Department of Pediatrics (Cardiology), Stanford University School of Medicine, Stanford, CA 94305
| | - Thomas C Irving
- BioCAT, Department of Biological Sciences, Illinois Institute of Technology, Chicago, IL 60616
| | - Roger Cooke
- Department of Biochemistry, University of California, San Francisco, CA 94158
| | | | - James A Spudich
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305;
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305
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13
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Sack KL, Dabiri Y, Franz T, Solomon SD, Burkhoff D, Guccione JM. Investigating the Role of Interventricular Interdependence in Development of Right Heart Dysfunction During LVAD Support: A Patient-Specific Methods-Based Approach. Front Physiol 2018; 9:520. [PMID: 29867563 PMCID: PMC5962934 DOI: 10.3389/fphys.2018.00520] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Accepted: 04/23/2018] [Indexed: 02/01/2023] Open
Abstract
Predictive computation models offer the potential to uncover the mechanisms of treatments whose actions cannot be easily determined by experimental or imaging techniques. This is particularly relevant for investigating left ventricular mechanical assistance, a therapy for end-stage heart failure, which is increasingly used as more than just a bridge-to-transplant therapy. The high incidence of right ventricular failure following left ventricular assistance reflects an undesired consequence of treatment, which has been hypothesized to be related to the mechanical interdependence between the two ventricles. To investigate the implication of this interdependence specifically in the setting of left ventricular assistance device (LVAD) support, we introduce a patient-specific finite-element model of dilated chronic heart failure. The model geometry and material parameters were calibrated using patient-specific clinical data, producing a mechanical surrogate of the failing in vivo heart that models its dynamic strain and stress throughout the cardiac cycle. The model of the heart was coupled to lumped-parameter circulatory systems to simulate realistic ventricular loading conditions. Finally, the impact of ventricular assistance was investigated by incorporating a pump with pressure-flow characteristics of an LVAD (HeartMate II™ operating between 8 and 12 k RPM) in parallel to the left ventricle. This allowed us to investigate the mechanical impact of acute left ventricular assistance at multiple operating-speeds on right ventricular mechanics and septal wall motion. Our findings show that left ventricular assistance reduces myofiber stress in the left ventricle and, to a lesser extent, right ventricle free wall, while increasing leftward septal-shift with increased operating-speeds. These effects were achieved with secondary, potentially negative effects on the interventricular septum which showed that support from LVADs, introduces unnatural bending of the septum and with it, increased localized stress regions. Left ventricular assistance unloads the left ventricle significantly and shifts the right ventricular pressure-volume-loop toward larger volumes and higher pressures; a consequence of left-to-right ventricular interactions and a leftward septal shift. The methods and results described in the present study are a meaningful advancement of computational efforts to investigate heart-failure therapies in silico and illustrate the potential of computational models to aid understanding of complex mechanical and hemodynamic effects of new therapies.
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Affiliation(s)
- Kevin L Sack
- Division of Biomedical Engineering, Department of Human Biology, University of Cape Town, Cape Town, South Africa.,Department of Surgery, University of California, San Francisco, San Francisco, CA, United States
| | - Yaghoub Dabiri
- Department of Surgery, University of California, San Francisco, San Francisco, CA, United States
| | - Thomas Franz
- Division of Biomedical Engineering, Department of Human Biology, University of Cape Town, Cape Town, South Africa.,Bioengineering Science Research Group, Engineering Sciences, Faculty of Engineering and the Environment, University of Southampton, Southampton, United Kingdom
| | - Scott D Solomon
- Department of Medicine, Brigham and Women's Hospital, Boston, MA, United States
| | - Daniel Burkhoff
- Cardiovascular Research Foundation, New York, NY, United States
| | - Julius M Guccione
- Department of Surgery, University of California, San Francisco, San Francisco, CA, United States
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14
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Popović ZB, Sato K, Desai MY. Is universal grading of diastolic function by echocardiography feasible? Cardiovasc Diagn Ther 2018. [PMID: 29541608 DOI: 10.21037/cdt.2017.07.02] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Quantitation of diastolic function centers on the assessment of active and passive ventricular properties, and involves measurement estimates of ventricular relaxation, and chamber and myocardial stiffness. Diastolic dysfunction is a propensity to develop increased left ventricular (LV) end-diastolic pressure. Recently American Society of Echocardiography and European Association of Cardiovascular Imaging (ASE/EACVI) proposed a new grading system. While the new guidelines are ambiguous and with cutoff points that may misclassify patients as both sicker and healthier than they are. This article outlines the pathophysiology behind the diastolic dysfunction and role and limitation of echocardiographic assessment in predicting LV diastolic dysfunction.
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Affiliation(s)
- Zoran B Popović
- Department of Cardiovascular Medicine, Heart and Vascular Institute, Cleveland Clinic, Cleveland, USA
| | - Kimi Sato
- Department of Cardiovascular Medicine, Heart and Vascular Institute, Cleveland Clinic, Cleveland, USA
| | - Milind Y Desai
- Department of Cardiovascular Medicine, Heart and Vascular Institute, Cleveland Clinic, Cleveland, USA
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15
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Abilez OJ, Tzatzalos E, Yang H, Zhao MT, Jung G, Zöllner AM, Tiburcy M, Riegler J, Matsa E, Shukla P, Zhuge Y, Chour T, Chen VC, Burridge PW, Karakikes I, Kuhl E, Bernstein D, Couture LA, Gold JD, Zimmermann WH, Wu JC. Passive Stretch Induces Structural and Functional Maturation of Engineered Heart Muscle as Predicted by Computational Modeling. Stem Cells 2018; 36:265-277. [PMID: 29086457 PMCID: PMC5785460 DOI: 10.1002/stem.2732] [Citation(s) in RCA: 97] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2015] [Revised: 10/18/2017] [Accepted: 10/23/2017] [Indexed: 12/16/2022]
Abstract
The ability to differentiate human pluripotent stem cells (hPSCs) into cardiomyocytes (CMs) makes them an attractive source for repairing injured myocardium, disease modeling, and drug testing. Although current differentiation protocols yield hPSC-CMs to >90% efficiency, hPSC-CMs exhibit immature characteristics. With the goal of overcoming this limitation, we tested the effects of varying passive stretch on engineered heart muscle (EHM) structural and functional maturation, guided by computational modeling. Human embryonic stem cells (hESCs, H7 line) or human induced pluripotent stem cells (IMR-90 line) were differentiated to hPSC-derived cardiomyocytes (hPSC-CMs) in vitro using a small molecule based protocol. hPSC-CMs were characterized by troponin+ flow cytometry as well as electrophysiological measurements. Afterwards, 1.2 × 106 hPSC-CMs were mixed with 0.4 × 106 human fibroblasts (IMR-90 line) (3:1 ratio) and type-I collagen. The blend was cast into custom-made 12-mm long polydimethylsiloxane reservoirs to vary nominal passive stretch of EHMs to 5, 7, or 9 mm. EHM characteristics were monitored for up to 50 days, with EHMs having a passive stretch of 7 mm giving the most consistent formation. Based on our initial macroscopic observations of EHM formation, we created a computational model that predicts the stress distribution throughout EHMs, which is a function of cellular composition, cellular ratio, and geometry. Based on this predictive modeling, we show cell alignment by immunohistochemistry and coordinated calcium waves by calcium imaging. Furthermore, coordinated calcium waves and mechanical contractions were apparent throughout entire EHMs. The stiffness and active forces of hPSC-derived EHMs are comparable with rat neonatal cardiomyocyte-derived EHMs. Three-dimensional EHMs display increased expression of mature cardiomyocyte genes including sarcomeric protein troponin-T, calcium and potassium ion channels, β-adrenergic receptors, and t-tubule protein caveolin-3. Passive stretch affects the structural and functional maturation of EHMs. Based on our predictive computational modeling, we show how to optimize cell alignment and calcium dynamics within EHMs. These findings provide a basis for the rational design of EHMs, which enables future scale-up productions for clinical use in cardiovascular tissue engineering. Stem Cells 2018;36:265-277.
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Affiliation(s)
- Oscar J. Abilez
- Stanford Cardiovascular Institute, Stanford, California, USA
- Institute for Stem Cell Biology and Regenerative Medicine, Stanford University, Stanford, California, USA
- Bio-X Program, Stanford University, Stanford, California, USA
- Department of Medicine, Division of Cardiovascular Medicine, Stanford University, Stanford, California, USA
| | - Evangeline Tzatzalos
- Stanford Cardiovascular Institute, Stanford, California, USA
- Institute for Stem Cell Biology and Regenerative Medicine, Stanford University, Stanford, California, USA
| | - Huaxiao Yang
- Stanford Cardiovascular Institute, Stanford, California, USA
- Institute for Stem Cell Biology and Regenerative Medicine, Stanford University, Stanford, California, USA
| | - Ming-Tao Zhao
- Stanford Cardiovascular Institute, Stanford, California, USA
- Institute for Stem Cell Biology and Regenerative Medicine, Stanford University, Stanford, California, USA
| | - Gwanghyun Jung
- Stanford Cardiovascular Institute, Stanford, California, USA
- Department of Pediatrics, Division of Cardiology, Stanford University, Stanford, California, USA
| | - Alexander M. Zöllner
- Department of Mechanical Engineering, Stanford University, Stanford, California, USA
| | - Malte Tiburcy
- Institute of Pharmacology and Toxicology, Heart Research Center, University Medical Center, Georg-August-University, Gӧttingen, Germany
- DZHK (German Center for Cardiovascular Research) Partner Site, Gӧttingen, Germany
| | - Johannes Riegler
- Stanford Cardiovascular Institute, Stanford, California, USA
- Institute for Stem Cell Biology and Regenerative Medicine, Stanford University, Stanford, California, USA
| | - Elena Matsa
- Stanford Cardiovascular Institute, Stanford, California, USA
- Institute for Stem Cell Biology and Regenerative Medicine, Stanford University, Stanford, California, USA
| | - Praveen Shukla
- Stanford Cardiovascular Institute, Stanford, California, USA
- Institute for Stem Cell Biology and Regenerative Medicine, Stanford University, Stanford, California, USA
| | - Yan Zhuge
- Stanford Cardiovascular Institute, Stanford, California, USA
- Institute for Stem Cell Biology and Regenerative Medicine, Stanford University, Stanford, California, USA
| | - Tony Chour
- Stanford Cardiovascular Institute, Stanford, California, USA
- Institute for Stem Cell Biology and Regenerative Medicine, Stanford University, Stanford, California, USA
| | - Vincent C. Chen
- Center for Biomedicine and Genetics, City of Hope, Duarte, California, USA
| | - Paul W. Burridge
- Stanford Cardiovascular Institute, Stanford, California, USA
- Institute for Stem Cell Biology and Regenerative Medicine, Stanford University, Stanford, California, USA
| | - Ioannis Karakikes
- Stanford Cardiovascular Institute, Stanford, California, USA
- Institute for Stem Cell Biology and Regenerative Medicine, Stanford University, Stanford, California, USA
| | - Ellen Kuhl
- Stanford Cardiovascular Institute, Stanford, California, USA
- Bio-X Program, Stanford University, Stanford, California, USA
- Department of Mechanical Engineering, Stanford University, Stanford, California, USA
| | - Daniel Bernstein
- Stanford Cardiovascular Institute, Stanford, California, USA
- Department of Pediatrics, Division of Cardiology, Stanford University, Stanford, California, USA
| | - Larry A. Couture
- Center for Biomedicine and Genetics, City of Hope, Duarte, California, USA
- Center for Applied Technology Development, City of Hope, Duarte, California, USA
| | - Joseph D. Gold
- Stanford Cardiovascular Institute, Stanford, California, USA
- Institute for Stem Cell Biology and Regenerative Medicine, Stanford University, Stanford, California, USA
| | - Wolfram H. Zimmermann
- Institute of Pharmacology and Toxicology, Heart Research Center, University Medical Center, Georg-August-University, Gӧttingen, Germany
- DZHK (German Center for Cardiovascular Research) Partner Site, Gӧttingen, Germany
| | - Joseph C. Wu
- Stanford Cardiovascular Institute, Stanford, California, USA
- Institute for Stem Cell Biology and Regenerative Medicine, Stanford University, Stanford, California, USA
- Bio-X Program, Stanford University, Stanford, California, USA
- Department of Medicine, Division of Cardiovascular Medicine, Stanford University, Stanford, California, USA
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16
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Wang X, Su L, Yang R, Zhang H, Liu D. Myocardial strain/stress changes identified by echocardiography may reveal early sepsis-induced myocardial dysfunction. J Int Med Res 2018; 46:1439-1454. [PMID: 29332410 PMCID: PMC6091847 DOI: 10.1177/0300060517737434] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Objective To perform early assessment of sepsis-induced myocardial dysfunction (SIMD) using strain/stress echocardiography. Methods A canine model of SIMD was established using intravenous injection of lipopolysaccharide (LPS, 2 mg/kg). Thirteen dogs were included, comprising an LPS-treated SIMD group (n = 7) and saline control group (n = 6). SIMD was assessed at various time-points using cardiac measurements including haemodynamics and echocardiography. Results Systolic and radial ventricular wall stress and circular ventricular wall stress (WSsc) were significantly lower in the sepsis group versus the control group at all time-points. Logistic regression analysis revealed an inverse correlation between stress rate of the front-posterior and bottom wall and left ventricle systolic wall strength. In contrast, a positive correlation was found between the mean velocity of circumferential fibre shortening (mVCF) or heart rate-adjusted mVCF (RVCF) and WSsc. Using regression equations, predicted values for mVCF and RVCF in animals with sepsis were significantly higher than measured values at 4- 5- and 6-h time-points. Conclusions These findings will further the understanding of pathophysiological alterations in SIMD at the early stage of sepsis, and suggest that strain rate may reflect the nature of myocardial contractility.
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Affiliation(s)
- Xiaoting Wang
- 1 Department of Critical Care Medicine, Peking Union Medical College Hospital, 34732 Peking Union Medical College & Chinese Academy of Medical Sciences, Beijing, China
| | - Longxiang Su
- 1 Department of Critical Care Medicine, Peking Union Medical College Hospital, 34732 Peking Union Medical College & Chinese Academy of Medical Sciences, Beijing, China
| | - Rongli Yang
- 2 Department of Critical Care Medicine, Dalian Central Hospital, Dalian, Liaoning Province, China
| | - Hongmin Zhang
- 1 Department of Critical Care Medicine, Peking Union Medical College Hospital, 34732 Peking Union Medical College & Chinese Academy of Medical Sciences, Beijing, China
| | - Dawei Liu
- 1 Department of Critical Care Medicine, Peking Union Medical College Hospital, 34732 Peking Union Medical College & Chinese Academy of Medical Sciences, Beijing, China
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17
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Chaui-Berlinck JG, Monteiro LHA. Frank-Starling mechanism and short-term adjustment of cardiac flow. ACTA ACUST UNITED AC 2017; 220:4391-4398. [PMID: 28912258 DOI: 10.1242/jeb.167106] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Accepted: 09/11/2017] [Indexed: 11/20/2022]
Abstract
The Frank-Starling law of the heart is a filling-force mechanism (FFm), a positive relationship between the distension of a ventricular chamber and its force of ejection, and such a mechanism is found across all the studied vertebrate lineages. The functioning of the cardiovascular system is usually described by means of the cardiac and vascular functions, the former related to the contractility of the heart and the latter related to the afterload imposed on the ventricle. The crossing of these functions is the so-called 'operation point', and the FFm is supposed to play a stabilizing role for the short-term variations in the working of the system. In the present study, we analyze whether the FFm is truly responsible for such a stability within two different settings: one-ventricle and two-ventricle hearts. To approach the query, we linearized the region around an arbitrary operation point and put forward a dynamical system of differential equations to describe the relationship among volumes in face of blood flows governed by pressure differences between compartments. Our results show that the FFm is not necessary to give stability to an operation point. Thus, which forces selected and maintained such a mechanism in all vertebrates? The present results indicate three different and complementary roles for the FFm: (1) it decreases the demands of a central controlling system over the circulatory system; (2) it smooths out perturbations in volumes; and (3) it guarantees faster transitions between operation points, i.e. it allows for rapid changes in cardiac output.
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Affiliation(s)
- José Guilherme Chaui-Berlinck
- Energetics and Theoretical Physiology Laboratory, Department of Physiology, Biosciences Institute, University of São Paulo, Rua do Matão, 101, CEP 05508-090, São Paulo, Brazil
| | - Luiz Henrique Alves Monteiro
- Escola de Engenharia da Universidade Presbiteriana Mackenzie, Rua da Consolação, 930 - Consolação, São Paulo - SP/Brasil, CEP 01302-907, Brazil.,Escola Politécnica da Universidade de São Paulo, Department of Telecommunications and Control, Av. Prof. Luciano Gualberto, 380 - CEP 05508-010 - São Paulo - SP/Brasil, Brazil
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18
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Hirschvogel M, Bassilious M, Jagschies L, Wildhirt SM, Gee MW. A monolithic 3D-0D coupled closed-loop model of the heart and the vascular system: Experiment-based parameter estimation for patient-specific cardiac mechanics. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2017; 33:e2842. [PMID: 27743468 DOI: 10.1002/cnm.2842] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2016] [Accepted: 10/09/2016] [Indexed: 06/06/2023]
Abstract
A model for patient-specific cardiac mechanics simulation is introduced, incorporating a 3-dimensional finite element model of the ventricular part of the heart, which is coupled to a reduced-order 0-dimensional closed-loop vascular system, heart valve, and atrial chamber model. The ventricles are modeled by a nonlinear orthotropic passive material law. The electrical activation is mimicked by a prescribed parameterized active stress acting along a generic muscle fiber orientation. Our activation function is constructed such that the start of ventricular contraction and relaxation as well as the active stress curve's slope are parameterized. The imaging-based patient-specific ventricular model is prestressed to low end-diastolic pressure to account for the imaged, stressed configuration. Visco-elastic Robin boundary conditions are applied to the heart base and the epicardium to account for the embedding surrounding. We treat the 3D solid-0D fluid interaction as a strongly coupled monolithic problem, which is consistently linearized with respect to 3D solid and 0D fluid model variables to allow for a Newton-type solution procedure. The resulting coupled linear system of equations is solved iteratively in every Newton step using 2 × 2 physics-based block preconditioning. Furthermore, we present novel efficient strategies for calibrating active contractile and vascular resistance parameters to experimental left ventricular pressure and stroke volume data gained in porcine experiments. Two exemplary states of cardiovascular condition are considered, namely, after application of vasodilatory beta blockers (BETA) and after injection of vasoconstrictive phenylephrine (PHEN). The parameter calibration to the specific individual and cardiovascular state at hand is performed using a 2-stage nonlinear multilevel method that uses a low-fidelity heart model to compute a parameter correction for the high-fidelity model optimization problem. We discuss 2 different low-fidelity model choices with respect to their ability to augment the parameter optimization. Because the periodic state conditions on the model (active stress, vascular pressures, and fluxes) are a priori unknown and also dependent on the parameters to be calibrated (and vice versa), we perform parameter calibration and periodic state condition estimation simultaneously. After a couple of heart beats, the calibration algorithm converges to a settled, periodic state because of conservation of blood volume within the closed-loop circulatory system. The proposed model and multilevel calibration method are cost-efficient and allow for an efficient determination of a patient-specific in silico heart model that reproduces physiological observations very well. Such an individual and state accurate model is an important predictive tool in intervention planning, assist device engineering and other medical applications.
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Affiliation(s)
- Marc Hirschvogel
- Mechanics & High Performance Computing Group, Technische Universität München, Parkring 35, 85748 Garching b. München, Germany
| | - Marina Bassilious
- Mechanics & High Performance Computing Group, Technische Universität München, Parkring 35, 85748 Garching b. München, Germany
| | - Lasse Jagschies
- Mechanics & High Performance Computing Group, Technische Universität München, Parkring 35, 85748 Garching b. München, Germany
| | | | - Michael W Gee
- Mechanics & High Performance Computing Group, Technische Universität München, Parkring 35, 85748 Garching b. München, Germany
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β-Arrestin mediates the Frank-Starling mechanism of cardiac contractility. Proc Natl Acad Sci U S A 2016; 113:14426-14431. [PMID: 27911784 DOI: 10.1073/pnas.1609308113] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The Frank-Starling law of the heart is a physiological phenomenon that describes an intrinsic property of heart muscle in which increased cardiac filling leads to enhanced cardiac contractility. Identified more than a century ago, the Frank-Starling relationship is currently known to involve length-dependent enhancement of cardiac myofilament Ca2+ sensitivity. However, the upstream molecular events that link cellular stretch to the length-dependent myofilament Ca2+ sensitivity are poorly understood. Because the angiotensin II type 1 receptor (AT1R) and the multifunctional transducer protein β-arrestin have been shown to mediate mechanosensitive cellular signaling, we tested the hypothesis that these two proteins are involved in the Frank-Starling mechanism of the heart. Using invasive hemodynamics, we found that mice lacking β-arrestin 1, β-arrestin 2, or AT1R were unable to generate a Frank-Starling force in response to changes in cardiac volume. Although wild-type mice pretreated with the conventional AT1R blocker losartan were unable to enhance cardiac contractility with volume loading, treatment with a β-arrestin-biased AT1R ligand to selectively activate β-arrestin signaling preserved the Frank-Starling relationship. Importantly, in skinned muscle fiber preparations, we found markedly impaired length-dependent myofilament Ca2+ sensitivity in β-arrestin 1, β-arrestin 2, and AT1R knockout mice. Our data reveal β-arrestin 1, β-arrestin 2, and AT1R as key regulatory molecules in the Frank-Starling mechanism, which potentially can be targeted therapeutically with β-arrestin-biased AT1R ligands.
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Mamidi R, Gresham KS, Verma S, Stelzer JE. Cardiac Myosin Binding Protein-C Phosphorylation Modulates Myofilament Length-Dependent Activation. Front Physiol 2016; 7:38. [PMID: 26913007 PMCID: PMC4753332 DOI: 10.3389/fphys.2016.00038] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Accepted: 01/28/2016] [Indexed: 11/13/2022] Open
Abstract
Cardiac myosin binding protein-C (cMyBP-C) phosphorylation is an important regulator of contractile function, however, its contributions to length-dependent changes in cross-bridge (XB) kinetics is unknown. Therefore, we performed mechanical experiments to quantify contractile function in detergent-skinned ventricular preparations isolated from wild-type (WT) hearts, and hearts expressing non-phosphorylatable cMyBP-C [Ser to Ala substitutions at residues Ser273, Ser282, and Ser302 (i.e., 3SA)], at sarcomere length (SL) 1.9 μm or 2.1μm, prior and following protein kinase A (PKA) treatment. Steady-state force generation measurements revealed a blunting in the length-dependent increase in myofilament Ca(2+)-sensitivity of force generation (pCa50) following an increase in SL in 3SA skinned myocardium compared to WT skinned myocardium. Dynamic XB behavior was assessed at submaximal Ca(2+)-activations by imposing an acute rapid stretch of 2% of initial muscle length, and measuring both the magnitudes and rates of resultant phases of force decay due to strain-induced XB detachment and delayed force rise due to recruitment of additional XBs with increased SL (i.e., stretch activation). The magnitude (P2) and rate of XB detachment (k rel) following stretch was significantly reduced in 3SA skinned myocardium compared to WT skinned myocardium at short and long SL, and prior to and following PKA treatment. Furthermore, the length-dependent acceleration of k rel due to decreased SL that was observed in WT skinned myocardium was abolished in 3SA skinned myocardium. PKA treatment accelerated the rate of XB recruitment (k df) following stretch at both SL's in WT but not in 3SA skinned myocardium. The amplitude of the enhancement in force generation above initial pre-stretch steady-state levels (P3) was not different between WT and 3SA skinned myocardium at any condition measured. However, the magnitude of the entire delayed force phase which can dip below initial pre-stretch steady-state levels (Pdf) was significantly lower in 3SA skinned myocardium under all conditions, in part due to a reduced magnitude of XB detachment (P2) in 3SA skinned myocardium compared to WT skinned myocardium. These findings demonstrate that cMyBP-C phospho-ablation regulates SL- and PKA-mediated effects on XB kinetics in the myocardium, which would be expected to contribute to the regulation of the Frank-Starling mechanism.
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Affiliation(s)
- Ranganath Mamidi
- Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University Cleveland, OH, USA
| | - Kenneth S Gresham
- Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University Cleveland, OH, USA
| | - Sujeet Verma
- Department of Horticultural Science, Institute of Food and Agricultural Sciences Gulf Coast Research and Education Center, University of Florida Wimauma, FL, USA
| | - Julian E Stelzer
- Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University Cleveland, OH, USA
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Tzatzalos E, Abilez OJ, Shukla P, Wu JC. Engineered heart tissues and induced pluripotent stem cells: Macro- and microstructures for disease modeling, drug screening, and translational studies. Adv Drug Deliv Rev 2016; 96:234-244. [PMID: 26428619 DOI: 10.1016/j.addr.2015.09.010] [Citation(s) in RCA: 105] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2015] [Revised: 09/16/2015] [Accepted: 09/23/2015] [Indexed: 01/01/2023]
Abstract
Engineered heart tissue has emerged as a personalized platform for drug screening. With the advent of induced pluripotent stem cell (iPSC) technology, patient-specific stem cells can be developed and expanded into an indefinite source of cells. Subsequent developments in cardiovascular biology have led to efficient differentiation of cardiomyocytes, the force-producing cells of the heart. iPSC-derived cardiomyocytes (iPSC-CMs) have provided potentially limitless quantities of well-characterized, healthy, and disease-specific CMs, which in turn has enabled and driven the generation and scale-up of human physiological and disease-relevant engineered heart tissues. The combined technologies of engineered heart tissue and iPSC-CMs are being used to study diseases and to test drugs, and in the process, have advanced the field of cardiovascular tissue engineering into the field of precision medicine. In this review, we will discuss current developments in engineered heart tissue, including iPSC-CMs as a novel cell source. We examine new research directions that have improved the function of engineered heart tissue by using mechanical or electrical conditioning or the incorporation of non-cardiomyocyte stromal cells. Finally, we discuss how engineered heart tissue can evolve into a powerful tool for therapeutic drug testing.
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Affiliation(s)
- Evangeline Tzatzalos
- Stanford Cardiovascular Institute
- Institute for Stem Cell Biology and Regenerative Medicine
| | - Oscar J Abilez
- Stanford Cardiovascular Institute
- Institute for Stem Cell Biology and Regenerative Medicine
- Bio-X Program
- Department of Medicine, Division of Cardiovascular Medicine
| | - Praveen Shukla
- Stanford Cardiovascular Institute
- Institute for Stem Cell Biology and Regenerative Medicine
| | - Joseph C Wu
- Stanford Cardiovascular Institute
- Institute for Stem Cell Biology and Regenerative Medicine
- Bio-X Program
- Department of Medicine, Division of Cardiovascular Medicine
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22
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Li AY, Stevens CM, Liang B, Rayani K, Little S, Davis J, Tibbits GF. Familial hypertrophic cardiomyopathy related cardiac troponin C L29Q mutation alters length-dependent activation and functional effects of phosphomimetic troponin I*. PLoS One 2013; 8:e79363. [PMID: 24260207 PMCID: PMC3832503 DOI: 10.1371/journal.pone.0079363] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2013] [Accepted: 09/27/2013] [Indexed: 11/18/2022] Open
Abstract
The Ca(2+) binding properties of the FHC-associated cardiac troponin C (cTnC) mutation L29Q were examined in isolated cTnC, troponin complexes, reconstituted thin filament preparations, and skinned cardiomyocytes. While higher Ca(2+) binding affinity was apparent for the L29Q mutant in isolated cTnC, this phenomenon was not observed in the cTn complex. At the level of the thin filament in the presence of phosphomimetic TnI, L29Q cTnC further reduced the Ca(2+) affinity by 27% in the steady-state measurement and increased the Ca(2+) dissociation rate by 20% in the kinetic studies. Molecular dynamics simulations suggest that L29Q destabilizes the conformation of cNTnC in the presence of phosphomimetic cTnI and potentially modulates the Ca(2+) sensitivity due to the changes of the opening/closing equilibrium of cNTnC. In the skinned cardiomyocyte preparation, L29Q cTnC increased Ca(2+) sensitivity in a highly sarcomere length (SL)-dependent manner. The well-established reduction of Ca(2+) sensitivity by phosphomimetic cTnI was diminished by 68% in the presence of the mutation and it also depressed the SL-dependent increase in myofilament Ca(2+) sensitivity. This might result from its modified interaction with cTnI which altered the feedback effects of cross-bridges on the L29Q cTnC-cTnI-Tm complex. This study demonstrates that the L29Q mutation alters the contractility and the functional effects of the phosphomimetic cTnI in both thin filament and single skinned cardiomyocytes and importantly that this effect is highly sarcomere length dependent.
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Affiliation(s)
- Alison Y. Li
- Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Charles M. Stevens
- Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, British Columbia, Canada
- Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Bo Liang
- Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Kaveh Rayani
- Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Sean Little
- Physiology and Cell Biology, The Ohio State University, Columbia, Ohio, United States of America
| | - Jonathan Davis
- Physiology and Cell Biology, The Ohio State University, Columbia, Ohio, United States of America
| | - Glen F. Tibbits
- Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, British Columbia, Canada
- Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia, Canada
- Cardiovascular Sciences, Child and Family Research Institute, Vancouver, British Columbia, Canada
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23
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Monasky MM, Taglieri DM, Jacobson AK, Haizlip KM, Solaro RJ, Janssen PM. Post-translational modifications of myofilament proteins involved in length-dependent prolongation of relaxation in rabbit right ventricular myocardium. Arch Biochem Biophys 2013; 535:22-9. [PMID: 23085150 PMCID: PMC3640662 DOI: 10.1016/j.abb.2012.10.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2012] [Revised: 10/02/2012] [Accepted: 10/10/2012] [Indexed: 12/27/2022]
Abstract
The phosphorylation state of several cardiac myofilament proteins changes with the level of stretch in intact, twitch-contracting cardiac muscles. It remains unclear which kinases are involved in the length-dependent phosphorylation of these proteins. We set out to investigate which kinases are involved after a step-wise change in cardiac muscle length. We hypothesize that myofilament protein phosphorylation by PKCβII and PKA alters contractile kinetics during length-dependent activation. Right ventricular intact trabeculae were isolated from New Zealand White rabbit hearts and stimulated to contract at 1Hz. Twitch force recordings where taken at taut and optimal muscle lengths before and after administration of kinase inhibitors at 37°C. PKCβII inhibition significantly decreased time from stimulation to peak force (TTP), time from peak force to 50% relaxation (RT50), and 90% relaxation (RT90) at optimal muscle length. This led to a loss in the length-dependent increase of RT50 and RT90 in the presence of the PKCβII inhibitor, whereas the length-dependent increase in RT50 and RT90 was seen in the controls. PKA inhibition using H-89 significantly decreased TTP at both taut and optimal muscle lengths. Detection of Ser/Thr phosphorylation with ProQ-diamond staining indicates a role for PKCβII in the phosphorylation of tropomyosin and myosin light chain-2 (MLC2) and PKA for tropomyosin, troponin-I, MLC2, myosin binding protein-C, troponin-T (TnT) 3 and TnT4. Our data provide evidence for two signaling kinases acting upon myofilament proteins during length-dependent activation, and provide further insight for length-dependent myofilament function.
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Affiliation(s)
- Michelle M. Monasky
- Department of Physiology and Cell Biology, College of Medicine and D. Davis Heart Lung Institute, The Ohio State University, 1645 Neil Avenue, Columbus, OH 43210-1218, USA
- Department of Physiology and Biophysics and Center for Cardiovascular Research, College of Medicine, University of Illinois at Chicago, 835 S. Wolcott Avenue (M/C 901), Chicago, IL 60612-7342, USA
| | - Domenico M. Taglieri
- Department of Physiology and Biophysics and Center for Cardiovascular Research, College of Medicine, University of Illinois at Chicago, 835 S. Wolcott Avenue (M/C 901), Chicago, IL 60612-7342, USA
| | - Alice K. Jacobson
- Department of Physiology and Cell Biology, College of Medicine and D. Davis Heart Lung Institute, The Ohio State University, 1645 Neil Avenue, Columbus, OH 43210-1218, USA
| | - Kaylan M. Haizlip
- Department of Physiology and Cell Biology, College of Medicine and D. Davis Heart Lung Institute, The Ohio State University, 1645 Neil Avenue, Columbus, OH 43210-1218, USA
| | - R. John Solaro
- Department of Physiology and Biophysics and Center for Cardiovascular Research, College of Medicine, University of Illinois at Chicago, 835 S. Wolcott Avenue (M/C 901), Chicago, IL 60612-7342, USA
| | - Paul M.L. Janssen
- Department of Physiology and Cell Biology, College of Medicine and D. Davis Heart Lung Institute, The Ohio State University, 1645 Neil Avenue, Columbus, OH 43210-1218, USA
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Land S, Niederer SA, Aronsen JM, Espe EKS, Zhang L, Louch WE, Sjaastad I, Sejersted OM, Smith NP. An analysis of deformation-dependent electromechanical coupling in the mouse heart. J Physiol 2012; 590:4553-69. [PMID: 22615436 PMCID: PMC3477757 DOI: 10.1113/jphysiol.2012.231928] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2012] [Accepted: 05/17/2012] [Indexed: 01/20/2023] Open
Abstract
To investigate the effects of the coupling between excitation and contraction on whole-organ function, we have developed a novel biophysically based multiscale electromechanical model of the murine heart. Through comparison with a comprehensive in vivo experimental data set, we show good agreement with pressure and volume measurements at both physiological temperatures and physiological pacing frequencies. This whole-organ model was used to investigate the effects of material and haemodynamic properties introduced at the tissue level, as well as emergent function of our novel cell contraction model. Through a comprehensive sensitivity analysis at both the cellular and whole organ level, we demonstrate the sensitivity of the model's results to its parameters and the constraining effect of experimental data. These results demonstrate the fundamental importance of length- and velocity-dependent feedback to the cellular scale for whole-organ function, and we show that a strong velocity dependence of tension is essential for explaining the differences between measured single cell tension and whole-organ pressure transients.
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Affiliation(s)
- Sander Land
- Department of Computer Science, University of Oxford, Oxford, UK
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25
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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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26
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Smith GA. Frank-Starling law and mass action calcium activation of the myofibril ATPase; comment on "de Tombe PP, Mateja RD, Tachampa K, Mou YA, Farman GP, Irving TC. Myofilament length dependent activation. J Mol Cell Cardiol 2010; 48: 851-8". J Mol Cell Cardiol 2010; 49:707-8; author reply 709. [PMID: 20624395 DOI: 10.1016/j.yjmcc.2010.07.003] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/05/2010] [Accepted: 07/07/2010] [Indexed: 11/24/2022]
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Abstract
Cardiovascular pathophysiological changes, such as hypertension and enlarged ventricles, reflect the altered functions of the heart and its circulation during ill-health. This article examines the normal and altered anatomy of the cardiac valves, the contractile elements and enzymes of the myocardium, the significance of the different factors associated with cardiac output, and the role of the autonomic nervous system in the heart beat. It also explores how certain diseases alter these functions and result in cardiac symptoms. Nurses can benefit from knowledge of these specific changes, for example, by being able to ask relevant questions in order to ascertain the nature of a patients condition, by being able to take an effective patient history and by being able to read diagnostic results, such as electrocardiograms and cardiac enzyme results. All this will help nurses to promote sound cardiac care based on a physiological rationale.
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Terui T, Sodnomtseren M, Matsuba D, Udaka J, Ishiwata S, Ohtsuki I, Kurihara S, Fukuda N. Troponin and titin coordinately regulate length-dependent activation in skinned porcine ventricular muscle. ACTA ACUST UNITED AC 2008; 131:275-83. [PMID: 18299397 PMCID: PMC2248715 DOI: 10.1085/jgp.200709895] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We investigated the molecular mechanism by which troponin (Tn) regulates the Frank-Starling mechanism of the heart. Quasi-complete reconstitution of thin filaments with rabbit fast skeletal Tn (sTn) attenuated length-dependent activation in skinned porcine left ventricular muscle, to a magnitude similar to that observed in rabbit fast skeletal muscle. The rate of force redevelopment increased upon sTn reconstitution at submaximal levels, coupled with an increase in Ca2+ sensitivity of force, suggesting the acceleration of cross-bridge formation and, accordingly, a reduction in the fraction of resting cross-bridges that can potentially produce additional active force. An increase in titin-based passive force, induced by manipulating the prehistory of stretch, enhanced length-dependent activation, in both control and sTn-reconstituted muscles. Furthermore, reconstitution of rabbit fast skeletal muscle with porcine left ventricular Tn enhanced length-dependent activation, accompanied by a decrease in Ca2+ sensitivity of force. These findings demonstrate that Tn plays an important role in the Frank-Starling mechanism of the heart via on–off switching of the thin filament state, in concert with titin-based regulation.
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Affiliation(s)
- Takako Terui
- Department of Cell Physiology, The Jikei University School of Medicine, Tokyo 105-8461, Japan.
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29
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dos Remedios CG. The regulation of muscle contraction: as in life, it keeps getting more complex. Biophys J 2007; 93:4097-8. [PMID: 17890400 PMCID: PMC2098728 DOI: 10.1529/biophysj.107.117762] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- C G dos Remedios
- Muscle Research Unit, Bosch Institute, The University of Sydney, Sydney, Australia.
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