1
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Teitgen AE, Hock MT, McCabe KJ, Childers MC, Huber GA, Marzban B, Beard DA, McCammon JA, Regnier M, McCulloch AD. Multiscale modeling shows how 2'-deoxy-ATP rescues ventricular function in heart failure. Proc Natl Acad Sci U S A 2024; 121:e2322077121. [PMID: 39172779 DOI: 10.1073/pnas.2322077121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Accepted: 07/22/2024] [Indexed: 08/24/2024] Open
Abstract
2'-deoxy-ATP (dATP) improves cardiac function by increasing the rate of crossbridge cycling and Ca[Formula: see text] transient decay. However, the mechanisms of these effects and how therapeutic responses to dATP are achieved when dATP is only a small fraction of the total ATP pool remain poorly understood. Here, we used a multiscale computational modeling approach to analyze the mechanisms by which dATP improves ventricular function. We integrated atomistic simulations of prepowerstroke myosin and actomyosin association, filament-scale Markov state modeling of sarcomere mechanics, cell-scale analysis of myocyte Ca[Formula: see text] dynamics and contraction, organ-scale modeling of biventricular mechanoenergetics, and systems level modeling of circulatory dynamics. Molecular and Brownian dynamics simulations showed that dATP increases the actomyosin association rate by 1.9 fold. Markov state models predicted that dATP increases the pool of myosin heads available for crossbridge cycling, increasing steady-state force development at low dATP fractions by 1.3 fold due to mechanosensing and nearest-neighbor cooperativity. This was found to be the dominant mechanism by which small amounts of dATP can improve contractile function at myofilament to organ scales. Together with faster myocyte Ca[Formula: see text] handling, this led to improved ventricular contractility, especially in a failing heart model in which dATP increased ejection fraction by 16% and the energy efficiency of cardiac contraction by 1%. This work represents a complete multiscale model analysis of a small molecule myosin modulator from single molecule to organ system biophysics and elucidates how the molecular mechanisms of dATP may improve cardiovascular function in heart failure with reduced ejection fraction.
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Affiliation(s)
- Abigail E Teitgen
- Department of Bioengineering, University of California San Diego, La Jolla, CA 92093
| | - Marcus T Hock
- Department of Bioengineering, University of California San Diego, La Jolla, CA 92093
| | - Kimberly J McCabe
- Department of Computational Physiology, Simula Research Laboratory, Oslo 0164, Norway
| | - Matthew C Childers
- Department of Bioengineering, University of Washington, Seattle, WA 98109
| | - Gary A Huber
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, CA 92093
| | - Bahador Marzban
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48109
| | - Daniel A Beard
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48109
| | - J Andrew McCammon
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, CA 92093
| | - Michael Regnier
- Department of Bioengineering, University of Washington, Seattle, WA 98109
| | - Andrew D McCulloch
- Department of Bioengineering, University of California San Diego, La Jolla, CA 92093
- Department of Medicine, University of California San Diego, La Jolla, CA 92093
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2
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Schmidt AA, Grosberg AY, Grosberg A. A novel kinetic model to demonstrate the independent effects of ATP and ADP/Pi concentrations on sarcomere function. PLoS Comput Biol 2024; 20:e1012321. [PMID: 39102392 PMCID: PMC11326600 DOI: 10.1371/journal.pcbi.1012321] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2024] [Revised: 08/15/2024] [Accepted: 07/12/2024] [Indexed: 08/07/2024] Open
Abstract
Understanding muscle contraction mechanisms is a standing challenge, and one of the approaches has been to create models of the sarcomere-the basic contractile unit of striated muscle. While these models have been successful in elucidating many aspects of muscle contraction, they fall short in explaining the energetics of functional phenomena, such as rigor, and in particular, their dependence on the concentrations of the biomolecules involved in the cross-bridge cycle. Our hypothesis posits that the stochastic time delay between ATP adsorption and ADP/Pi release in the cross-bridge cycle necessitates a modeling approach where the rates of these two reaction steps are controlled by two independent parts of the total free energy change of the hydrolysis reaction. To test this hypothesis, we built a two-filament, stochastic-mechanical half-sarcomere model that separates the energetic roles of ATP and ADP/Pi in the cross-bridge cycle's free energy landscape. Our results clearly demonstrate that there is a nontrivial dependence of the cross-bridge cycle's kinetics on the independent concentrations of ATP, ADP, and Pi. The simplicity of the proposed model allows for analytical solutions of the more basic systems, which provide novel insight into the dominant mechanisms driving some of the experimentally observed contractile phenomena.
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Affiliation(s)
- Andrew A Schmidt
- Department of Biomedical Engineering, University of California, Irvine, Irvine, California, United States of America
- UCI Edwards Lifesciences Foundation Cardiovascular Innovation and Research Center (CIRC), University of California, Irvine, Irvine, California, United States of America
| | - Alexander Y Grosberg
- Department of Physics and Center for Soft Matter Research, New York University, New York, New York, United States of America
| | - Anna Grosberg
- Department of Biomedical Engineering, University of California, Irvine, Irvine, California, United States of America
- UCI Edwards Lifesciences Foundation Cardiovascular Innovation and Research Center (CIRC), University of California, Irvine, Irvine, California, United States of America
- Department of Chemical & Biomolecular Engineering, University of California, Irvine, Irvine, California, United States of America
- The NSF-Simons Center for Multiscale Cell Fate Research and Sue and Bill Gross Stem Cell Research Center and Center for Complex Biological Systems, University of California, Irvine, Irvine, California, United States of America
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3
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Colebank MJ, Oomen PA, Witzenburg CM, Grosberg A, Beard DA, Husmeier D, Olufsen MS, Chesler NC. Guidelines for mechanistic modeling and analysis in cardiovascular research. Am J Physiol Heart Circ Physiol 2024; 327:H473-H503. [PMID: 38904851 DOI: 10.1152/ajpheart.00766.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/11/2023] [Revised: 06/07/2024] [Accepted: 06/16/2024] [Indexed: 06/22/2024]
Abstract
Computational, or in silico, models are an effective, noninvasive tool for investigating cardiovascular function. These models can be used in the analysis of experimental and clinical data to identify possible mechanisms of (ab)normal cardiovascular physiology. Recent advances in computing power and data management have led to innovative and complex modeling frameworks that simulate cardiovascular function across multiple scales. While commonly used in multiple disciplines, there is a lack of concise guidelines for the implementation of computer models in cardiovascular research. In line with recent calls for more reproducible research, it is imperative that scientists adhere to credible practices when developing and applying computational models to their research. The goal of this manuscript is to provide a consensus document that identifies best practices for in silico computational modeling in cardiovascular research. These guidelines provide the necessary methods for mechanistic model development, model analysis, and formal model calibration using fundamentals from statistics. We outline rigorous practices for computational, mechanistic modeling in cardiovascular research and discuss its synergistic value to experimental and clinical data.
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Affiliation(s)
- Mitchel J Colebank
- Edwards Lifesciences Foundation Cardiovascular Innovation and Research Center, Department of Biomedical Engineering, University of California, Irvine, Irvine, California, United States
| | - Pim A Oomen
- Edwards Lifesciences Foundation Cardiovascular Innovation and Research Center, Department of Biomedical Engineering, University of California, Irvine, Irvine, California, United States
| | - Colleen M Witzenburg
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, Wisconsin, United States
| | - Anna Grosberg
- Edwards Lifesciences Foundation Cardiovascular Innovation and Research Center, Department of Biomedical Engineering, University of California, Irvine, Irvine, California, United States
| | - Daniel A Beard
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan, United States
| | - Dirk Husmeier
- School of Mathematics and Statistics, University of Glasgow, Glasgow, United Kingdom
| | - Mette S Olufsen
- Department of Mathematics, North Carolina State University, Raleigh, North Carolina, United States
| | - Naomi C Chesler
- Edwards Lifesciences Foundation Cardiovascular Innovation and Research Center, Department of Biomedical Engineering, University of California, Irvine, Irvine, California, United States
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4
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Lewalle A, Milburn G, Campbell KS, Niederer SA. Cardiac length-dependent activation driven by force-dependent thick-filament dynamics. Biophys J 2024:S0006-3495(24)00352-7. [PMID: 38807364 DOI: 10.1016/j.bpj.2024.05.025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2024] [Revised: 04/17/2024] [Accepted: 05/23/2024] [Indexed: 05/30/2024] Open
Abstract
The length-dependent activation (LDA) of maximum force and calcium sensitivity are established features of cardiac muscle contraction but the dominant underlying mechanisms remain to be fully clarified. Alongside the well-documented regulation of contraction via the thin filaments, experiments have identified an additional force-dependent thick-filament activation, whereby myosin heads parked in a so-called off state become available to generate force. This process produces a feedback effect that may potentially drive LDA. Using biomechanical modeling of a human left-ventricular myocyte, this study investigates the extent to which the off-state dynamics could, by itself, plausibly account for LDA, depending on the specific mathematical formulation of the feedback. We hypothesized four different models of the off-state regulatory feedback based on (A) total force, (B) active force, (C) sarcomere strain, and (D) passive force. We tested if these models could reproduce the isometric steady-state and dynamic LDA features predicted by an earlier published model of a human left-ventricle myocyte featuring purely phenomenological length dependences. The results suggest that only total-force feedback (A) is capable of reproducing the expected behaviors, but that passive tension could provide a length-dependent signal on which to initiate the feedback. Furthermore, by attributing LDA to off-state dynamics, our proposed model also qualitatively reproduces experimentally observed effects of the off-state-stabilizing drug mavacamten. Taken together, these results support off-state dynamics as a plausible primary mechanism underlying LDA.
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Affiliation(s)
- Alexandre Lewalle
- National Heart and Lung Institute, Faculty of Medicine, Imperial College London, London, United Kingdom.
| | - Gregory Milburn
- Department of Physiology, University of Kentucky, Lexington, Kentucky
| | - Kenneth S Campbell
- Division of Cardiovascular Medicine, University of Kentucky, Lexington, Kentucky
| | - Steven A Niederer
- National Heart and Lung Institute, Faculty of Medicine, Imperial College London, London, United Kingdom
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5
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Musgrave JH, Han JC, Ward ML, Taberner AJ, Tran K. Analysis of metabolite and strain effects on cardiac cross-bridge dynamics using model linearisation techniques. Front Physiol 2024; 14:1323605. [PMID: 38292450 PMCID: PMC10825018 DOI: 10.3389/fphys.2023.1323605] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Accepted: 12/06/2023] [Indexed: 02/01/2024] Open
Abstract
Multi-scale models of cardiac energetics are becoming crucial in better understanding the prevalent chronic diseases operating at the intersection of metabolic and cardiovascular dysfunction. Computationally efficient models of cardiac cross-bridge kinetics that are sensitive to changes in metabolite concentrations are necessary to simulate the effects of disease-induced changes in cellular metabolic state on cardiac mechanics across disparate spatial scales. While these models do currently exist, deeper analysis of how the modelling of metabolite effects and the assignment of strain dependence within the cross-bridge cycle affect the properties of the model is required. In this study, model linearisation techniques were used to simulate and interrogate the complex modulus of an ODE-based model of cross-bridge kinetics. Active complex moduli were measured from permeabilised rat cardiac trabeculae under five different metabolite conditions with varying ATP and Pi concentrations. Sensitivity to metabolites was incorporated into an existing three-state cross-bridge model using either a direct dependence or a rapid equilibrium approach. Combining the two metabolite binding methods with all possible locations of strain dependence within the cross-bridge cycle produced 64 permutations of the cross-bridge model. Using linear model analysis, these models were systematically explored to determine the effects of metabolite binding and their interaction with strain dependence on the frequency response of cardiac muscle. The results showed that the experimentally observed effects of ATP and Pi concentrations on the cardiac complex modulus could be attributed to their regulation of cross-bridge detachment rates. Analysis of the cross-bridge models revealed a mechanistic basis for the biochemical schemes which place Pi release following cross-bridge formation and ATP binding prior to cross-bridge detachment. In addition, placing strain dependence on the reverse rate of the cross-bridge power stroke produced the model which most closely matched the experimental data. From these analyses, a well-justified metabolite-sensitive model of rat cardiac cross-bridge kinetics is presented which is suitable for parameterisation with other data sets and integration with multi-scale cardiac models.
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Affiliation(s)
- Julia H. Musgrave
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - June-Chiew Han
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - Marie-Louise Ward
- Department of Physiology, University of Auckland, Auckland, New Zealand
| | - Andrew J. Taberner
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
- Department of Engineering Science and Biomedical Engineering, University of Auckland, Auckland, New Zealand
| | - Kenneth Tran
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
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6
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Lopez-Schenk R, Collins NL, Schenk NA, Beard DA. Integrated Functions of Cardiac Energetics, Mechanics, and Purine Nucleotide Metabolism. Compr Physiol 2023; 14:5345-5369. [PMID: 38158366 PMCID: PMC10956446 DOI: 10.1002/cphy.c230011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2024]
Abstract
Purine nucleotides play central roles in energy metabolism in the heart. Most fundamentally, the free energy of hydrolysis of the adenine nucleotide adenosine triphosphate (ATP) provides the thermodynamic driving force for numerous cellular processes including the actin-myosin crossbridge cycle. Perturbations to ATP supply and/or demand in the myocardium lead to changes in the homeostatic balance between purine nucleotide synthesis, degradation, and salvage, potentially affecting myocardial energetics and, consequently, myocardial mechanics. Indeed, both acute myocardial ischemia and decompensatory remodeling of the myocardium in heart failure are associated with depletion of myocardial adenine nucleotides and with impaired myocardial mechanical function. Yet there remain gaps in the understanding of mechanistic links between adenine nucleotide degradation and contractile dysfunction in heart disease. The scope of this article is to: (i) review current knowledge of the pathways of purine nucleotide depletion and salvage in acute ischemia and in chronic heart disease; (ii) review hypothesized mechanisms linking myocardial mechanics and energetics with myocardial adenine nucleotide regulation; and (iii) highlight potential targets for treating myocardial metabolic and mechanical dysfunction associated with these pathways. It is hypothesized that an imbalance in the degradation, salvage, and synthesis of adenine nucleotides leads to a net loss of adenine nucleotides in both acute ischemia and under chronic high-demand conditions associated with the development of heart failure. This reduction in adenine nucleotide levels results in reduced myocardial ATP and increased myocardial inorganic phosphate. Both of these changes have the potential to directly impact tension development and mechanical work at the cellular level. © 2024 American Physiological Society. Compr Physiol 14:5345-5369, 2024.
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Affiliation(s)
- Rachel Lopez-Schenk
- Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan, USA
| | - Nicole L Collins
- Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan, USA
| | - Noah A Schenk
- Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan, USA
| | - Daniel A Beard
- Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan, USA
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7
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Ghosh S, Guglielmi G, Orfanidis I, Spill F, Hickey A, Hanssen E, Rajagopal V. Effects of altered cellular ultrastructure on energy metabolism in diabetic cardiomyopathy: an in silico study. Philos Trans R Soc Lond B Biol Sci 2022; 377:20210323. [PMID: 36189807 PMCID: PMC9527921 DOI: 10.1098/rstb.2021.0323] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Diabetic cardiomyopathy is a leading cause of heart failure in diabetes. At the cellular level, diabetic cardiomyopathy leads to altered mitochondrial energy metabolism and cardiomyocyte ultrastructure. We combined electron microscopy (EM) and computational modelling to understand the impact of diabetes-induced ultrastructural changes on cardiac bioenergetics. We collected transverse micrographs of multiple control and type I diabetic rat cardiomyocytes using EM. Micrographs were converted to finite-element meshes, and bioenergetics was simulated over them using a biophysical model. The simulations also incorporated depressed mitochondrial capacity for oxidative phosphorylation (OXPHOS) and creatine kinase (CK) reactions to simulate diabetes-induced mitochondrial dysfunction. Analysis of micrographs revealed a 14% decline in mitochondrial area fraction in diabetic cardiomyocytes, and an irregular arrangement of mitochondria and myofibrils. Simulations predicted that this irregular arrangement, coupled with the depressed activity of mitochondrial CK enzymes, leads to large spatial variation in adenosine diphosphate (ADP)/adenosine triphosphate (ATP) ratio profile of diabetic cardiomyocytes. However, when spatially averaged, myofibrillar ADP/ATP ratios of a cardiomyocyte do not change with diabetes. Instead, average concentration of inorganic phosphate rises by 40% owing to lower mitochondrial area fraction and dysfunction in OXPHOS. These simulations indicate that a disorganized cellular ultrastructure negatively impacts metabolite transport in diabetic cardiomyopathy. This article is part of the theme issue ‘The cardiomyocyte: new revelations on the interplay between architecture and function in growth, health, and disease’.
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Affiliation(s)
- Shouryadipta Ghosh
- CSIRO Data61, Commonwealth Scientific and Industrial Research Organisation, Research Way, Clayton, VIC 3168, Australia.,Department of Biomedical Engineering, University of Melbourne, Parkville, VIC 3010, Australia
| | - Giovanni Guglielmi
- Department of Biomedical Engineering, University of Melbourne, Parkville, VIC 3010, Australia.,School of Mathematics, University of Birmingham, Edgbaston B15 2TS, UK
| | - Ioannis Orfanidis
- Health Data Specialists, Grand Canal Docklands, Dublin D02 VK08, Republic of Ireland
| | - Fabian Spill
- School of Mathematics, University of Birmingham, Edgbaston B15 2TS, UK
| | - Anthony Hickey
- School of Biological Sciences, University of Auckland, Auckland, NZ 1042, New Zealand
| | - Eric Hanssen
- Ian Holmes Imaging Center and Department of Biochemistry and Pharmacology, Bio21 Institute, University of Melbourne, Parkville, VIC 3010, Australia
| | - Vijay Rajagopal
- Department of Biomedical Engineering, University of Melbourne, Parkville, VIC 3010, Australia
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8
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Musgrave JH, Han JC, Ward ML, Taberner AJ, Loiselle DS, Tran K. Uncovering cross-bridge properties that underlie the cardiac active complex modulus using model linearisation techniques. Math Biosci 2022; 353:108922. [DOI: 10.1016/j.mbs.2022.108922] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Revised: 09/12/2022] [Accepted: 10/12/2022] [Indexed: 11/05/2022]
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9
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Beard DA, Marzban B, Li OY, Campbell KS, Janssen PML, Chesler NC, Baker AJ. Reduced cardiac muscle power with low ATP simulating heart failure. Biophys J 2022; 121:3213-3223. [PMID: 35918899 PMCID: PMC9463691 DOI: 10.1016/j.bpj.2022.07.029] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Revised: 06/20/2022] [Accepted: 07/22/2022] [Indexed: 11/23/2022] Open
Abstract
For patients with heart failure, myocardial ATP level can be reduced to one-half of that observed in healthy controls. This marked reduction (from ≈8 mM in healthy controls to as low as 3-4 mM in heart failure) has been suggested to contribute to impaired myocardial contraction and to the decreased pump function characteristic of heart failure. However, in vitro measures of maximum myofilament force generation, maximum shortening velocity, and the actomyosin ATPase activity show effective KM values for MgATP ranging from ≈10 μM to 150 μM, well below the intracellular ATP level in heart failure. Thus, it is not clear that the fall of myocardial ATP observed in heart failure is sufficient to impair the function of the contractile proteins. Therefore, we tested the effect of low MgATP levels on myocardial contraction using demembranated cardiac muscle preparations that were exposed to MgATP levels typical of the range found in non-failing and failing hearts. Consistent with previous studies, we found that a 50% reduction in MgATP level (from 8 mM to 4 mM) did not reduce maximum force generation or maximum velocity of shortening. However, we found that a 50% reduction in MgATP level caused a 20%-25% reduction in maximal power generation (measured during muscle shortening against a load) and a 20% slowing of cross-bridge cycling kinetics. These results suggest that the decreased cellular ATP level occurring in heart failure contributes to the impaired pump function of the failing heart. Since the ATP-myosin ATPase dissociation constant is estimated to be submillimolar, these findings also suggest that MgATP concentration affects cross-bridge dynamics through a mechanism that is more complex than through the direct dependence of MgATP concentration on myosin ATPase activity. Finally, these studies suggest that therapies targeted to increase adenine nucleotide pool levels in cardiomyocytes might be beneficial for treating heart failure.
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Affiliation(s)
- Daniel A Beard
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan
| | - Bahador Marzban
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan
| | - On Yeung Li
- Veterans Affairs Medical Center, San Francisco, California; Department of Medicine, University of California, San Francisco, California
| | - Kenneth S Campbell
- Department of Physiology and Division of Cardiovascular Medicine, University of Kentucky, Lexington, Kentucky
| | - Paul M L Janssen
- Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, Ohio
| | - Naomi C Chesler
- Edwards Lifesciences Foundation Cardiovascular Innovation and Research Center and Department of Biomedical Engineering, University of California, Irvine, Irvine, California
| | - Anthony J Baker
- Veterans Affairs Medical Center, San Francisco, California; Department of Medicine, University of California, San Francisco, California.
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10
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Odeigah OO, Valdez-Jasso D, Wall ST, Sundnes J. Computational models of ventricular mechanics and adaptation in response to right-ventricular pressure overload. Front Physiol 2022; 13:948936. [PMID: 36091369 PMCID: PMC9449365 DOI: 10.3389/fphys.2022.948936] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Accepted: 08/03/2022] [Indexed: 12/13/2022] Open
Abstract
Pulmonary arterial hypertension (PAH) is associated with substantial remodeling of the right ventricle (RV), which may at first be compensatory but at a later stage becomes detrimental to RV function and patient survival. Unlike the left ventricle (LV), the RV remains understudied, and with its thin-walled crescent shape, it is often modeled simply as an appendage of the LV. Furthermore, PAH diagnosis is challenging because it often leaves the LV and systemic circulation largely unaffected. Several treatment strategies such as atrial septostomy, right ventricular assist devices (RVADs) or RV resynchronization therapy have been shown to improve RV function and the quality of life in patients with PAH. However, evidence of their long-term efficacy is limited and lung transplantation is still the most effective and curative treatment option. As such, the clinical need for improved diagnosis and treatment of PAH drives a strong need for increased understanding of drivers and mechanisms of RV growth and remodeling (G&R), and more generally for targeted research into RV mechanics pathology. Computational models stand out as a valuable supplement to experimental research, offering detailed analysis of the drivers and consequences of G&R, as well as a virtual test bench for exploring and refining hypotheses of growth mechanisms. In this review we summarize the current efforts towards understanding RV G&R processes using computational approaches such as reduced-order models, three dimensional (3D) finite element (FE) models, and G&R models. In addition to an overview of the relevant literature of RV computational models, we discuss how the models have contributed to increased scientific understanding and to potential clinical treatment of PAH patients.
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Affiliation(s)
| | - Daniela Valdez-Jasso
- Department of Bioengineering, University of California, San Diego, San Diego, CA, United States
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11
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Park J, Wu Z, Steiner PR, Zhu B, Zhang JXJ. Heart-on-Chip for Combined Cellular Dynamics Measurements and Computational Modeling Towards Clinical Applications. Ann Biomed Eng 2022; 50:111-137. [PMID: 35039976 DOI: 10.1007/s10439-022-02902-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Accepted: 01/01/2022] [Indexed: 12/24/2022]
Abstract
Organ-on-chip or micro-engineered three-dimensional cellular or tissue models are increasingly implemented in the study of cardiovascular pathophysiology as alternatives to traditional in vitro cell culture. Drug induced cardiotoxicity is a key issue in drug development pipelines, but the current in vitro and in vivo studies suffer from inter-species differences, high costs, and lack of reliability and accuracy in predicting cardiotoxicity. Microfluidic heart-on-chip devices can impose a paradigm shift to the current tools. They can not only recapitulate cardiac tissue level functionality and the communication between cells and extracellular matrices but also allow higher throughput studies conducive to drug screening especially with their added functionalities or sensors that extract disease-specific phenotypic, genotypic, and electrophysiological information in real-time. Such electrical and mechanical components can tailor the electrophysiology and mechanobiology of the experiment to better mimic the in vivo condition as well. Recent advancements and challenges are reviewed in the fabrication, functionalization and sensor assisted mechanical and electrophysiological measurements, numerical and computational modeling of cardiomyocytes' behavior, and the clinical applications in drug screening and disease modeling. This review concludes with the current challenges and perspectives on the future of such organ-on-chip platforms.
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Affiliation(s)
- Jiyoon Park
- Thayer School of Engineering, Dartmouth College, Hanover, NH, 03755, USA
| | - Ziqian Wu
- Thayer School of Engineering, Dartmouth College, Hanover, NH, 03755, USA
| | - Paul R Steiner
- Dartmouth-Hitchcock Medical Center, 1 Medical Center Dr, Lebanon, NH, 03766, USA
| | - Bo Zhu
- Computer Science Department, Dartmouth College, Hanover, NH, 03755, USA
| | - John X J Zhang
- Thayer School of Engineering, Dartmouth College, Hanover, NH, 03755, USA. .,Dartmouth-Hitchcock Medical Center, 1 Medical Center Dr, Lebanon, NH, 03766, USA.
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12
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Sun L, Wang H, Xu D, Yu S, Zhang L, Li X. Lapatinib induces mitochondrial dysfunction to enhance oxidative stress and ferroptosis in doxorubicin-induced cardiomyocytes via inhibition of PI3K/AKT signaling pathway. Bioengineered 2021; 13:48-60. [PMID: 34898356 PMCID: PMC8805895 DOI: 10.1080/21655979.2021.2004980] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Lapatinib (LAP) is an important anti-cancer drug and is frequently alongside doxorubicin (DOX) as a combination therapy for better anti-cancer efficacy. However, many studies have reported that LAP in combination with DOX may induce highly cardiotoxicity. Accordingly, we aimed to explore the potential mechanism involved in the synergistic effect of LAP in DOX-induced cardiotoxicity. Here, cell counting kit-8 was used to detect cell viability and lactate dehydrogenase measurement was performed to assess cell injury. Cell apoptosis was evaluated by TUNEL assay and western blot assay. Mitochondrial dysfunction was identified by JC-1 assay, adenosine triphosphate (ATP) and Cytochrome C. Moreover, the activity of ROS, SOD, CAT and GSH were measured to elucidate oxidative stress level. Ferroptosis was examined by levels of Fe2+, GPX4 and ASCL4. Expressions of PI3K/AKT signaling were identified by western blot assay. The results revealed that LAP inhibited the cell viability and exacerbated cell injury induced by Dox, as well as increased cell apoptosis. LAP aggravated DOX-induced mitochondria damage by changed mitochondrial membrane potential, decreased ATP and increased level of Cytochrome C. In addition, the combination of LAP and DOX induced oxidative stress and ferroptosis in H9c2 cells. The activation of PI3K/AKT signaling reversed the detrimental effects of LAP on DOX-induced H9c2 cells. The data in this study showed for the first time that LAP aggravated Dox-induced cardiotoxicity by promoting oxidative stress and ferroptosis in cardiomyocytes via PI3K/AKT-mediated mitochondrial dysfunction, suggesting that PI3K/AKT activation is a promising cardioprotective strategy for DOX /LAX combination therapies.
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Affiliation(s)
- Lei Sun
- Ultrasonic Department, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China
| | - Hua Wang
- Ultrasonic Department, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China
| | - Dan Xu
- Ultrasonic Department, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China
| | - Shanshan Yu
- Ultrasonic Department, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China
| | - Lin Zhang
- Ultrasonic Department, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China
| | - Xiaopeng Li
- Ultrasonic Department, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China
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13
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Cowley AW, Dash RK. Computational/Experimental Interrogation of the Failing Heart-A Perspective on "Impaired Myocardial Energetics Causes Mechanical Dysfunction in Decompensated Failing Hearts". FUNCTION (OXFORD, ENGLAND) 2020; 1:zqaa022. [PMID: 35330639 PMCID: PMC8788834 DOI: 10.1093/function/zqaa022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Revised: 09/24/2020] [Accepted: 10/07/2020] [Indexed: 01/06/2023]
Affiliation(s)
- Allen W Cowley
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI 53226, USA,Address correspondence to A.W.C. (e-mail: )
| | - Ranjan K Dash
- Department of Biomedical Engineering, Medical College of Wisconsin, Milwaukee, WI 53226, USA
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14
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Lopez R, Marzban B, Gao X, Lauinger E, Van den Bergh F, Whitesall SE, Converso-Baran K, Burant CF, Michele DE, Beard DA. Impaired Myocardial Energetics Causes Mechanical Dysfunction in Decompensated Failing Hearts. FUNCTION 2020; 1:zqaa018. [PMID: 33074265 PMCID: PMC7552914 DOI: 10.1093/function/zqaa018] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Revised: 09/11/2020] [Accepted: 09/21/2020] [Indexed: 01/06/2023] Open
Abstract
Cardiac mechanical function is supported by ATP hydrolysis, which provides the chemical-free energy to drive the molecular processes underlying cardiac pumping. Physiological rates of myocardial ATP consumption require the heart to resynthesize its entire ATP pool several times per minute. In the failing heart, cardiomyocyte metabolic dysfunction leads to a reduction in the capacity for ATP synthesis and associated free energy to drive cellular processes. Yet it remains unclear if and how metabolic/energetic dysfunction that occurs during heart failure affects mechanical function of the heart. We hypothesize that changes in phosphate metabolite concentrations (ATP, ADP, inorganic phosphate) that are associated with decompensation and failure have direct roles in impeding contractile function of the myocardium in heart failure, contributing to the whole-body phenotype. To test this hypothesis, a transverse aortic constriction (TAC) rat model of pressure overload, hypertrophy, and decompensation was used to assess relationships between metrics of whole-organ pump function and myocardial energetic state. A multiscale computational model of cardiac mechanoenergetic coupling was used to identify and quantify the contribution of metabolic dysfunction to observed mechanical dysfunction. Results show an overall reduction in capacity for oxidative ATP synthesis fueled by either fatty acid or carbohydrate substrates as well as a reduction in total levels of adenine nucleotides and creatine in myocardium from TAC animals compared to sham-operated controls. Changes in phosphate metabolite levels in the TAC rats are correlated with impaired mechanical function, consistent with the overall hypothesis. Furthermore, computational analysis of myocardial metabolism and contractile dynamics predicts that increased levels of inorganic phosphate in TAC compared to control animals kinetically impair the myosin ATPase crossbridge cycle in decompensated hypertrophy/heart failure.
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Affiliation(s)
- Rachel Lopez
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, USA
| | - Bahador Marzban
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, USA
| | - Xin Gao
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, USA
| | - Ellen Lauinger
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, USA
| | - Françoise Van den Bergh
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, USA
| | - Steven E Whitesall
- Frankel Cardiovascular Center Physiology and Phenotyping Core, University of Michigan, Ann Arbor, MI, USA
| | - Kimber Converso-Baran
- Frankel Cardiovascular Center Physiology and Phenotyping Core, University of Michigan, Ann Arbor, MI, USA
| | - Charles F Burant
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, USA,Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA
| | - Daniel E Michele
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, USA,Frankel Cardiovascular Center Physiology and Phenotyping Core, University of Michigan, Ann Arbor, MI, USA
| | - Daniel A Beard
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, USA,Address correspondence to D.A.B. (e-mail: )
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15
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Liu L, Zhang D, Li Y. LncRNAs in cardiac hypertrophy: From basic science to clinical application. J Cell Mol Med 2020; 24:11638-11645. [PMID: 32896990 PMCID: PMC7579708 DOI: 10.1111/jcmm.15819] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Revised: 07/29/2020] [Accepted: 08/11/2020] [Indexed: 12/12/2022] Open
Abstract
Cardiac hypertrophy is a typical pathological phenotype of cardiomyopathy and a result from pathological remodelling of cardiomyocytes in humans. At present, emerging evidence demonstrated the roles of long non‐coding RNAs (lncRNAs) in regulating the pathophysiological process of cardiac hypertrophy. Herein, we would like to review the recent researches on this issue and try to analysis the potential therapeutic targets on lncRNA sites. Studies have revealed both genetic mutations related hypertrophic cardiomyopathy and the compensative cardiac hypertrophy due to pressure overload, inflammation, endocrine issues and other external stimulations, share a common molecular mechanism of ventricular hypertrophy. The emerging evidence identified the abnormal expression of lncRNAs would leading to the impairment the function of sarcomere, intracellular calcium handling and mitochondrial metabolisms. Several researches proved the therapeutic role of lncRNAs in preventing or reversing cardiac hypertrophy. With the development of delivery system for small pieces of oligonucleotide, clinicians could design gene therapy approaches to terminate the process of cardiac hypertrophy to provide better prognosis.
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Affiliation(s)
- Lei Liu
- Key Laboratory of Birth Defects and Related Diseases of Women and Children of MOE, Department of Pediatrics, West China Second University Hospital, Sichuan University, Chengdu, China
| | - Donghui Zhang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Science, Hubei University, Wuhan, China
| | - Yifei Li
- Key Laboratory of Birth Defects and Related Diseases of Women and Children of MOE, Department of Pediatrics, West China Second University Hospital, Sichuan University, Chengdu, China
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16
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Pewowaruk RJ, Philip JL, Tewari SG, Chen CS, Nyaeme MS, Wang Z, Tabima DM, Baker AJ, Beard DA, Chesler NC. Multiscale Computational Analysis of Right Ventricular Mechanoenergetics. J Biomech Eng 2019; 140:2679646. [PMID: 30003251 DOI: 10.1115/1.4040044] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Indexed: 11/08/2022]
Abstract
Right ventricular (RV) failure, which occurs in the setting of pressure overload, is characterized by abnormalities in mechanical and energetic function. The effects of these cell- and tissue-level changes on organ-level RV function are unknown. The primary aim of this study was to investigate the effects of myofiber mechanics and mitochondrial energetics on organ-level RV function in the context of pressure overload using a multiscale model of the cardiovascular system. The model integrates the mitochondria-generated metabolite concentrations that drive intracellular actin-myosin cross-bridging and extracellular myocardial tissue mechanics in a biventricular heart model coupled with simple lumped parameter circulations. Three types of pressure overload were simulated and compared to experimental results. The computational model was able to capture a wide range of cardiovascular physiology and pathophysiology from mild RV dysfunction to RV failure. Our results confirm that, in response to pressure overload alone, the RV is able to maintain cardiac output (CO) and predict that alterations in either RV active myofiber mechanics or RV metabolite concentrations are necessary to decrease CO.
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Affiliation(s)
- Ryan J Pewowaruk
- Mem. ASME Biomedical Engineering, University of Wisconsin-Madison, 2145 Engineering Centers Building, 1550 Engineering Drive, Madison, WI 53706 e-mail:
| | - Jennifer L Philip
- Surgery, University of Wisconsin-Madison, , 1550 Engineering Drive, Madison, WI 53706 e-mail:
| | - Shivendra G Tewari
- Molecular & Integrative Physiology, University of Michigan-Ann Arbor, , North Campus Research Center, Ann Arbor, MI 48109-5622 e-mail:
| | - Claire S Chen
- Mechanical Engineering, University of Wisconsin-Madison, , 1550 Engineering Drive, Madison, WI 53706 e-mail:
| | - Mark S Nyaeme
- Biomedical Engineering, University of Wisconsin-Madison, , 1550 Engineering Drive, Madison, WI 53706 e-mail:
| | - Zhijie Wang
- Mechanical Engineering, Colorado State University, , Fort Collins, CO 80521 e-mail:
| | - Diana M Tabima
- Biomedical Engineering, University of Wisconsin-Madison, , 1550 Engineering Drive, Madison, WI 53706 e-mail:
| | - Anthony J Baker
- Medicine, University of California-San Francisco, , San Francisco, CA 94121; VA Medical Center, 4150 Clement St., San Francisco, CA 94121 e-mail:
| | - Daniel A Beard
- Molecular & Integrative Physiology, University of Michigan-Ann Arbor, , North Campus Research Center, Ann Arbor, MI 48109-5622 e-mail:
| | - Naomi C Chesler
- Fellow ASME Biomedical Engineering, University of Wisconsin-Madison Medicine, , 1550 Engineering Drive, Madison, WI 53706 e-mail:
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17
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Cardiac Metabolic Limitations Contribute to Diminished Performance of the Heart in Aging. Biophys J 2019; 117:2295-2302. [PMID: 31395314 DOI: 10.1016/j.bpj.2019.06.026] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Revised: 05/24/2019] [Accepted: 06/05/2019] [Indexed: 01/15/2023] Open
Abstract
Changes in the myocardial energetics associated with aging-reductions in creatine phosphate/ATP ratio, total creatine, and ATP-mirror changes observed in failing hearts compared to healthy controls. Similarly, both aging and heart failure are associated with significant reductions in cardiac performance and maximal left ventricular cardiac power output compared with young healthy individuals. Based on these observations, we hypothesize that reductions in the concentrations of cytoplasmic adenine nucleotide, creatine, and phosphate pools that occur with aging impair the myocardial capacity to synthesize ATP at physiological free energy levels and that the resulting changes to myocardial energetic status impair the mechanical pumping ability of the heart. The purpose of this study is to test these hypotheses using an age-structured population model for myocardial metabolism in the adult female population and to determine the potential impact of reductions in key myocardial metabolite pools in causing metabolic/energetic and cardiac mechanical dysfunction associated with aging. To test these hypotheses, we developed a population model for myocardial energetics to predict myocardial ATP, ADP, creatine phosphate, creatine, and inorganic phosphate concentrations as functions of cardiac work and age in the adult female population. Model predictions support our hypotheses and are consistent with previous experimental observations. The major findings provide a novel, to our knowledge, theoretical and computational framework for further probing complex relationships between the energetics and performance of the heart with aging.
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18
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Niederer SA, Campbell KS, Campbell SG. A short history of the development of mathematical models of cardiac mechanics. J Mol Cell Cardiol 2019; 127:11-19. [PMID: 30503754 PMCID: PMC6525149 DOI: 10.1016/j.yjmcc.2018.11.015] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/30/2018] [Revised: 11/02/2018] [Accepted: 11/21/2018] [Indexed: 11/15/2022]
Abstract
Cardiac mechanics plays a crucial role in atrial and ventricular function, in the regulation of growth and remodelling, in the progression of disease, and the response to treatment. The spatial scale of the critical mechanisms ranges from nm (molecules) to cm (hearts) with the fastest events occurring in milliseconds (molecular events) and the slowest requiring months (growth and remodelling). Due to its complexity and importance, cardiac mechanics has been studied extensively both experimentally and through mathematical models and simulation. Models of cardiac mechanics evolved from seminal studies in skeletal muscle, and developed into cardiac specific, species specific, human specific and finally patient specific calculations. These models provide a formal framework to link multiple experimental assays recorded over nearly 100 years into a single unified representation of cardiac function. This review first provides a summary of the proteins, physiology and anatomy involved in the generation of cardiac pump function. We then describe the evolution of models of cardiac mechanics starting with the early theoretical frameworks describing the link between sarcomeres and muscle contraction, transitioning through myosin-level models to calcium-driven systems, and ending with whole heart patient-specific models.
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Affiliation(s)
| | - Kenneth S Campbell
- Department of Physiology and Division of Cardiovascular Medicine, University of Kentucky, Lexington, USA
| | - Stuart G Campbell
- Departments of Biomedical Engineering and Cellular and Molecular Physiology, Yale University, New Haven, USA
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19
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Ghosh S, Tran K, Delbridge LMD, Hickey AJR, Hanssen E, Crampin EJ, Rajagopal V. Insights on the impact of mitochondrial organisation on bioenergetics in high-resolution computational models of cardiac cell architecture. PLoS Comput Biol 2018; 14:e1006640. [PMID: 30517098 PMCID: PMC6296675 DOI: 10.1371/journal.pcbi.1006640] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Revised: 12/17/2018] [Accepted: 11/13/2018] [Indexed: 01/05/2023] Open
Abstract
Recent electron microscopy data have revealed that cardiac mitochondria are not arranged in crystalline columns but are organised with several mitochondria aggregated into columns of varying sizes spanning the cell cross-section. This raises the question—how does the mitochondrial arrangement affect the metabolite distributions within cardiomyocytes and what is its impact on force dynamics? Here, we address this question by employing finite element modeling of cardiac bioenergetics on computational meshes derived from electron microscope images. Our results indicate that heterogeneous mitochondrial distributions can lead to significant spatial variation across the cell in concentrations of inorganic phosphate, creatine (Cr) and creatine phosphate (PCr). However, our model predicts that sufficient activity of the creatine kinase (CK) system, coupled with rapid diffusion of Cr and PCr, maintains near uniform ATP and ADP ratios across the cell cross sections. This homogenous distribution of ATP and ADP should also evenly distribute force production and twitch duration with contraction. These results suggest that the PCr shuttle and associated enzymatic reactions act to maintain uniform force dynamics in the cell despite the heterogeneous mitochondrial organization. However, our model also predicts that under hypoxia activity of mitochondrial CK enzymes and diffusion of high-energy phosphate compounds may be insufficient to sustain uniform ATP/ADP distribution and hence force generation. Mammalian cardiomyocytes contain a high volume of mitochondria, which maintains the continuous and bulk supply of ATP to sustain normal heart function. Previously, cardiac mitochondria were understood to be distributed in a regular, crystalline pattern, which facilitated a steady supply of ATP at different workloads. Using electron microscopy images of cell cross sections, we recently found that they are not regularly distributed inside cardiomyocytes. We created new spatially accurate computational models of cardiac cell bioenergetics and tested whether this heterogeneous distribution of mitochondria causes non-uniform energy supply and contractile force production in the cardiomyocyte. We found that ATP and ADP concentrations remain uniform throughout the cell because of the activity of creatine kinase (CK) enzymes that convert ATP produced in the mitochondria into creatine phosphate. Creatine phosphate rapidly diffuses to the myofibril region where it can be converted back to ATP for the contraction cycle in a timely manner. This mechanism is called the phosphocreatine shuttle (PCr shuttle). The PCr shuttle ensures that different areas of the cell produce the same amount of force regardless of the mitochondrial distribution. However, our model also shows that when the cellular oxygen supply is limited—as can be the case in conditions such as heart failure—the PCr shuttle cannot maintain uniform ATP and ADP concentrations across the cell. This causes a non-uniform acto-myosin force distribution and non-uniform twitch duration across the cell cross section. Our study suggests that mechanisms other than the PCr shuttle may be necessary to maintain uniform supply of ATP in a hypoxic environment.
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Affiliation(s)
- Shouryadipta Ghosh
- Cell Structure and Mechanobiology Group, Dept. of Biomedical Engineering, Melbourne School of Engineering, University of Melbourne, Melbourne, Australia
- Systems Biology Laboratory, School of Mathematics and Statistics, and Melbourne School of Engineering, University of Melbourne, Melbourne, Australia
| | - Kenneth Tran
- Auckland Bioengineering Institute, University of Auckland, Auckland New Zealand
| | | | | | - Eric Hanssen
- Advanced Microscopy Facility, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Australia
| | - Edmund J. Crampin
- Systems Biology Laboratory, School of Mathematics and Statistics, and Melbourne School of Engineering, University of Melbourne, Melbourne, Australia
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, University of Melbourne, Melbourne, Australia
| | - Vijay Rajagopal
- Cell Structure and Mechanobiology Group, Dept. of Biomedical Engineering, Melbourne School of Engineering, University of Melbourne, Melbourne, Australia
- * E-mail:
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20
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Philip JL, Pewowaruk RJ, Chen CS, Tabima DM, Beard DA, Baker AJ, Chesler NC. Impaired Myofilament Contraction Drives Right Ventricular Failure Secondary to Pressure Overload: Model Simulations, Experimental Validation, and Treatment Predictions. Front Physiol 2018; 9:731. [PMID: 29997518 PMCID: PMC6030352 DOI: 10.3389/fphys.2018.00731] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Accepted: 05/25/2018] [Indexed: 12/31/2022] Open
Abstract
Introduction: Pulmonary hypertension (PH) causes pressure overload leading to right ventricular failure (RVF). Myocardial structure and myocyte mechanics are altered in RVF but the direct impact of these cellular level factors on organ level function remain unclear. A computational model of the cardiovascular system that integrates cellular function into whole organ function has recently been developed. This model is a useful tool for investigating how changes in myocyte structure and mechanics contribute to organ function. We use this model to determine how measured changes in myocyte and myocardial mechanics contribute to RVF at the organ level and predict the impact of myocyte-targeted therapy. Methods: A multiscale computational framework was tuned to model PH due to bleomycin exposure in mice. Pressure overload was modeled by increasing the pulmonary vascular resistance (PVR) and decreasing pulmonary artery compliance (CPA). Myocardial fibrosis and the impairment of myocyte maximum force generation (Fmax) were simulated by increasing the collagen content (↑PVR + ↓CPA + fibrosis) and decreasing Fmax (↑PVR + ↓CPA + fibrosis + ↓Fmax). A61603 (A6), a selective α1A-subtype adrenergic receptor agonist, shown to improve Fmax was simulated to explore targeting myocyte generated Fmax in PH. Results: Increased afterload (RV systolic pressure and arterial elastance) in simulations matched experimental results for bleomycin exposure. Pressure overload alone (↑PVR + ↓CPA) caused decreased RV ejection fraction (EF) similar to experimental findings but preservation of cardiac output (CO). Myocardial fibrosis in the setting of pressure overload (↑PVR + ↓PAC + fibrosis) had minimal impact compared to pressure overload alone. Including impaired myocyte function (↑PVR + ↓PAC + fibrosis + ↓Fmax) reduced CO, similar to experiment, and impaired EF. Simulations predicted that A6 treatment preserves EF and CO despite maintained RV pressure overload. Conclusion: Multiscale computational modeling enabled prediction of the contribution of cellular level changes to whole organ function. Impaired Fmax is a key feature that directly contributes to RVF. Simulations further demonstrate the therapeutic benefit of targeting Fmax, which warrants additional study. Future work should incorporate growth and remodeling into the computational model to enable prediction of the multiscale drivers of the transition from dysfunction to failure.
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Affiliation(s)
- Jennifer L. Philip
- Department of Biomedical Engineering, University of Wisconsin–Madison, Madison, WI, United States
- Department of Surgery, University of Wisconsin–Madison, Madison, WI, United States
| | - Ryan J. Pewowaruk
- Department of Biomedical Engineering, University of Wisconsin–Madison, Madison, WI, United States
| | - Claire S. Chen
- Department of Mechanical Engineering, University of Wisconsin–Madison, Madison, WI, United States
| | - Diana M. Tabima
- Department of Biomedical Engineering, University of Wisconsin–Madison, Madison, WI, United States
| | - Daniel A. Beard
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, United States
| | - Anthony J. Baker
- San Francisco Veterans Affairs Medical Center, San Francisco, CA, United States
- Department of Medicine, University of California, San Francisco, San Francisco, CA, United States
| | - Naomi C. Chesler
- Department of Biomedical Engineering, University of Wisconsin–Madison, Madison, WI, United States
- Department of Mechanical Engineering, University of Wisconsin–Madison, Madison, WI, United States
- Department of Medicine, University of Wisconsin–Madison, Madison, WI, United States
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21
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Bakermans AJ, Bazil JN, Nederveen AJ, Strijkers GJ, Boekholdt SM, Beard DA, Jeneson JAL. Human Cardiac 31P-MR Spectroscopy at 3 Tesla Cannot Detect Failing Myocardial Energy Homeostasis during Exercise. Front Physiol 2017; 8:939. [PMID: 29230178 PMCID: PMC5712006 DOI: 10.3389/fphys.2017.00939] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2017] [Accepted: 11/06/2017] [Indexed: 12/17/2022] Open
Abstract
Phosphorus-31 magnetic resonance spectroscopy (31P-MRS) is a unique non-invasive imaging modality for probing in vivo high-energy phosphate metabolism in the human heart. We investigated whether current 31P-MRS methodology would allow for clinical applications to detect exercise-induced changes in (patho-)physiological myocardial energy metabolism. Hereto, measurement variability and repeatability of three commonly used localized 31P-MRS methods [3D image-selected in vivo spectroscopy (ISIS) and 1D ISIS with 1D chemical shift imaging (CSI) oriented either perpendicular or parallel to the surface coil] to quantify the myocardial phosphocreatine (PCr) to adenosine triphosphate (ATP) ratio in healthy humans (n = 8) at rest were determined on a clinical 3 Tesla MR system. Numerical simulations of myocardial energy homeostasis in response to increased cardiac work rates were performed using a biophysical model of myocardial oxidative metabolism. Hypertrophic cardiomyopathy was modeled by either inefficient sarcomere ATP utilization or decreased mitochondrial ATP synthesis. The effect of creatine depletion on myocardial energy homeostasis was explored for both conditions. The mean in vivo myocardial PCr/ATP ratio measured with 3D ISIS was 1.57 ± 0.17 with a large repeatability coefficient of 40.4%. For 1D CSI in a 1D ISIS-selected slice perpendicular to the surface coil, the PCr/ATP ratio was 2.78 ± 0.50 (repeatability 42.5%). With 1D CSI in a 1D ISIS-selected slice parallel to the surface coil, the PCr/ATP ratio was 1.70 ± 0.56 (repeatability 43.7%). The model predicted a PCr/ATP ratio reduction of only 10% at the maximal cardiac work rate in normal myocardium. Hypertrophic cardiomyopathy led to lower PCr/ATP ratios for high cardiac work rates, which was exacerbated by creatine depletion. Simulations illustrated that when conducting cardiac 31P-MRS exercise stress testing with large measurement error margins, results obtained under pathophysiologic conditions may still lie well within the 95% confidence interval of normal myocardial PCr/ATP dynamics. Current measurement precision of localized 31P-MRS for quantification of the myocardial PCr/ATP ratio precludes the detection of the changes predicted by computational modeling. This hampers clinical employment of 31P-MRS for diagnostic testing and risk stratification, and warrants developments in cardiac 31P-MRS exercise stress testing methodology.
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Affiliation(s)
- Adrianus J Bakermans
- Department of Radiology, Academic Medical Center, University of Amsterdam, Amsterdam, Netherlands
| | - Jason N Bazil
- Department of Physiology, Michigan State University, East Lansing, MI, United States
| | - Aart J Nederveen
- Department of Radiology, Academic Medical Center, University of Amsterdam, Amsterdam, Netherlands
| | - Gustav J Strijkers
- Biomedical Engineering and Physics, Academic Medical Center, University of Amsterdam, Amsterdam, Netherlands
| | - S Matthijs Boekholdt
- Department of Cardiology, Academic Medical Center, University of Amsterdam, Amsterdam, Netherlands
| | - Daniel A Beard
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, United States
| | - Jeroen A L Jeneson
- Department of Radiology, Academic Medical Center, University of Amsterdam, Amsterdam, Netherlands.,Neuroimaging Center, Department of Neuroscience, University Medical Center Groningen, University of Groningen, Groningen, Netherlands
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22
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Shim JV, Chun B, van Hasselt JGC, Birtwistle MR, Saucerman JJ, Sobie EA. Mechanistic Systems Modeling to Improve Understanding and Prediction of Cardiotoxicity Caused by Targeted Cancer Therapeutics. Front Physiol 2017; 8:651. [PMID: 28951721 PMCID: PMC5599787 DOI: 10.3389/fphys.2017.00651] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Accepted: 08/16/2017] [Indexed: 12/13/2022] Open
Abstract
Tyrosine kinase inhibitors (TKIs) are highly potent cancer therapeutics that have been linked with serious cardiotoxicity, including left ventricular dysfunction, heart failure, and QT prolongation. TKI-induced cardiotoxicity is thought to result from interference with tyrosine kinase activity in cardiomyocytes, where these signaling pathways help to control critical processes such as survival signaling, energy homeostasis, and excitation–contraction coupling. However, mechanistic understanding is limited at present due to the complexities of tyrosine kinase signaling, and the wide range of targets inhibited by TKIs. Here, we review the use of TKIs in cancer and the cardiotoxicities that have been reported, discuss potential mechanisms underlying cardiotoxicity, and describe recent progress in achieving a more systematic understanding of cardiotoxicity via the use of mechanistic models. In particular, we argue that future advances are likely to be enabled by studies that combine large-scale experimental measurements with Quantitative Systems Pharmacology (QSP) models describing biological mechanisms and dynamics. As such approaches have proven extremely valuable for understanding and predicting other drug toxicities, it is likely that QSP modeling can be successfully applied to cardiotoxicity induced by TKIs. We conclude by discussing a potential strategy for integrating genome-wide expression measurements with models, illustrate initial advances in applying this approach to cardiotoxicity, and describe challenges that must be overcome to truly develop a mechanistic and systematic understanding of cardiotoxicity caused by TKIs.
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Affiliation(s)
- Jaehee V Shim
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount SinaiNew York, NY, United States
| | - Bryan Chun
- Department of Biomedical Engineering, University of VirginiaCharlottesville, VA, United States
| | - Johan G C van Hasselt
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount SinaiNew York, NY, United States
| | - Marc R Birtwistle
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount SinaiNew York, NY, United States
| | - Jeffrey J Saucerman
- Department of Biomedical Engineering, University of VirginiaCharlottesville, VA, United States
| | - Eric A Sobie
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount SinaiNew York, NY, United States
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23
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Marshall-Colon A, Long SP, Allen DK, Allen G, Beard DA, Benes B, von Caemmerer S, Christensen AJ, Cox DJ, Hart JC, Hirst PM, Kannan K, Katz DS, Lynch JP, Millar AJ, Panneerselvam B, Price ND, Prusinkiewicz P, Raila D, Shekar RG, Shrivastava S, Shukla D, Srinivasan V, Stitt M, Turk MJ, Voit EO, Wang Y, Yin X, Zhu XG. Crops In Silico: Generating Virtual Crops Using an Integrative and Multi-scale Modeling Platform. FRONTIERS IN PLANT SCIENCE 2017; 8:786. [PMID: 28555150 PMCID: PMC5430029 DOI: 10.3389/fpls.2017.00786] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Accepted: 04/26/2017] [Indexed: 05/18/2023]
Abstract
Multi-scale models can facilitate whole plant simulations by linking gene networks, protein synthesis, metabolic pathways, physiology, and growth. Whole plant models can be further integrated with ecosystem, weather, and climate models to predict how various interactions respond to environmental perturbations. These models have the potential to fill in missing mechanistic details and generate new hypotheses to prioritize directed engineering efforts. Outcomes will potentially accelerate improvement of crop yield, sustainability, and increase future food security. It is time for a paradigm shift in plant modeling, from largely isolated efforts to a connected community that takes advantage of advances in high performance computing and mechanistic understanding of plant processes. Tools for guiding future crop breeding and engineering, understanding the implications of discoveries at the molecular level for whole plant behavior, and improved prediction of plant and ecosystem responses to the environment are urgently needed. The purpose of this perspective is to introduce Crops in silico (cropsinsilico.org), an integrative and multi-scale modeling platform, as one solution that combines isolated modeling efforts toward the generation of virtual crops, which is open and accessible to the entire plant biology community. The major challenges involved both in the development and deployment of a shared, multi-scale modeling platform, which are summarized in this prospectus, were recently identified during the first Crops in silico Symposium and Workshop.
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Affiliation(s)
- Amy Marshall-Colon
- Department of Plant Biology, University of Illinois at Urbana–Champaign, UrbanaIL, USA
| | - Stephen P. Long
- Department of Plant Biology, University of Illinois at Urbana–Champaign, UrbanaIL, USA
- Carl R. Woese Institute for Genomic Biology, University of Illinois, Urbana–Champaign, UrbanaIL, USA
- Department of Crop Sciences, University of Illinois, UrbanaIL, USA
| | - Douglas K. Allen
- United States Department of Agriculture – Agricultural Research Service–Donald Danforth Plant Science Center, St. LouisMO, USA
| | - Gabrielle Allen
- Department of Astronomy–College of Education, University of Illinois at Urbana–Champaign, UrbanaIL, USA
| | - Daniel A. Beard
- Department of Molecular & Integrative Physiology, University of Michigan, Ann ArborMI, USA
| | - Bedrich Benes
- Department of Computer Graphics Technology, Purdue University, West LafayetteIN, USA
| | - Susanne von Caemmerer
- ARC Centre of Excellence for Translational Photosynthesis, Research School of Biological Sciences, Australian National University, ActonACT, Australia
| | - A. J. Christensen
- National Center for Supercomputing Applications, University of Illinois at Urbana–Champaign, UrbanaIL, USA
| | - Donna J. Cox
- National Center for Supercomputing Applications, University of Illinois at Urbana–Champaign, UrbanaIL, USA
| | - John C. Hart
- Department of Computer Science, University of Illinois at Urbana–Champaign, UrbanaIL, USA
| | - Peter M. Hirst
- Department of Horticulture and Landscape Architecture, Purdue University, West LafayetteIN, USA
| | - Kavya Kannan
- Department of Plant Biology, University of Illinois at Urbana–Champaign, UrbanaIL, USA
| | - Daniel S. Katz
- National Center for Supercomputing Applications, University of Illinois at Urbana–Champaign, UrbanaIL, USA
| | - Jonathan P. Lynch
- Department of Plant Science, Pennsylvania State University, University ParkPA, USA
- Centre for Plant Integrative Biology, University of NottinghamNottingham, UK
| | - Andrew J. Millar
- SynthSys and School of Biological Sciences, Edinburgh UniversityEdinburgh, UK
| | - Balaji Panneerselvam
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana–Champaign, UrbanaIL, USA
| | | | | | - David Raila
- National Center for Supercomputing Applications, University of Illinois at Urbana–Champaign, UrbanaIL, USA
| | - Rachel G. Shekar
- Carl R. Woese Institute for Genomic Biology, University of Illinois, Urbana–Champaign, UrbanaIL, USA
| | - Stuti Shrivastava
- Department of Plant Biology, University of Illinois at Urbana–Champaign, UrbanaIL, USA
| | - Diwakar Shukla
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana–Champaign, UrbanaIL, USA
| | - Venkatraman Srinivasan
- Carl R. Woese Institute for Genomic Biology, University of Illinois, Urbana–Champaign, UrbanaIL, USA
| | - Mark Stitt
- Max Planck Institute of Molecular Plant PhysiologyGolm, Germany
| | - Matthew J. Turk
- School of Information Science, University of Illinois, Urbana–Champaign, UrbanaIL, USA
| | - Eberhard O. Voit
- The Wallace H. Coulter Department of Biomedical Engineering, Georgia Tech and Emory University, AtlantaGA, USA
| | - Yu Wang
- Carl R. Woese Institute for Genomic Biology, University of Illinois, Urbana–Champaign, UrbanaIL, USA
| | - Xinyou Yin
- Centre for Crop Systems Analysis, Department of Plant Sciences, Wageningen University & ResearchWageningen, Netherlands
| | - Xin-Guang Zhu
- CAS Key Laboratory for Computational Biology–State Key Laboratory for Hybrid Rice, Partner Institute for Computational Biology, Chinese Academy of SciencesShanghai, China
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24
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Land S, Park-Holohan SJ, Smith NP, Dos Remedios CG, Kentish JC, Niederer SA. A model of cardiac contraction based on novel measurements of tension development in human cardiomyocytes. J Mol Cell Cardiol 2017; 106:68-83. [PMID: 28392437 DOI: 10.1016/j.yjmcc.2017.03.008] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Revised: 01/12/2017] [Accepted: 03/31/2017] [Indexed: 11/18/2022]
Abstract
Experimental data from human cardiac myocytes at body temperature is crucial for a quantitative understanding of clinically relevant cardiac function and development of whole-organ computational models. However, such experimental data is currently very limited. Specifically, important measurements to characterize changes in tension development in human cardiomyocytes that occur with perturbations in cell length are not available. To address this deficiency, in this study we present an experimental data set collected from skinned human cardiac myocytes, including the passive and viscoelastic properties of isolated myocytes, the steady-state force calcium relationship at different sarcomere lengths, and changes in tension following a rapid increase or decrease in length, and after constant velocity shortening. This data set is, to our knowledge, the first characterization of length and velocity-dependence of tension generation in human skinned cardiac myocytes at body temperature. We use this data to develop a computational model of contraction and passive viscoelasticity in human myocytes. Our model includes troponin C kinetics, tropomyosin kinetics, a three-state crossbridge model that accounts for the distortion of crossbridges, and the cellular viscoelastic response. Each component is parametrized using our experimental data collected in human cardiomyocytes at body temperature. Furthermore we are able to confirm that properties of length-dependent activation at 37°C are similar to other species, with a shift in calcium sensitivity and increase in maximum tension. We revise our model of tension generation in the skinned isolated myocyte to replicate reported tension traces generated in intact muscle during isometric tension, to provide a model of human tension generation for multi-scale simulations. This process requires changes to calcium sensitivity, cooperativity, and crossbridge transition rates. We apply this model within multi-scale simulations of biventricular cardiac function and further refine the parametrization within the whole organ context, based on obtaining a healthy ejection fraction. This process reveals that crossbridge cycling rates differ between skinned myocytes and intact myocytes.
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Affiliation(s)
- Sander Land
- Department of Biomedical Engineering, King's College London, UK.
| | - So-Jin Park-Holohan
- Cardiovascular Division, King's College London British Heart Foundation Centre of Research Excellence, UK
| | - Nicolas P Smith
- Department of Engineering Science, University of Auckland, New Zealand
| | | | - Jonathan C Kentish
- Cardiovascular Division, King's College London British Heart Foundation Centre of Research Excellence, UK
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26
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Tewari SG, Bugenhagen SM, Vinnakota KC, Rice JJ, Janssen PML, Beard DA. Influence of metabolic dysfunction on cardiac mechanics in decompensated hypertrophy and heart failure. J Mol Cell Cardiol 2016; 94:162-175. [PMID: 27085901 DOI: 10.1016/j.yjmcc.2016.04.003] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/21/2015] [Revised: 03/28/2016] [Accepted: 04/07/2016] [Indexed: 01/10/2023]
Abstract
Alterations in energetic state of the myocardium are associated with decompensated heart failure in humans and in animal models. However, the functional consequences of the observed changes in energetic state on mechanical function are not known. The primary aim of the study was to quantify mechanical/energetic coupling in the heart and to determine if energetic dysfunction can contribute to mechanical failure. A secondary aim was to apply a quantitative systems pharmacology analysis to investigate the effects of drugs that target cross-bridge cycling kinetics in heart failure-associated energetic dysfunction. Herein, a model of metabolite- and calcium-dependent myocardial mechanics was developed from calcium concentration and tension time courses in rat cardiac muscle obtained at different lengths and stimulation frequencies. The muscle dynamics model accounting for the effect of metabolites was integrated into a model of the cardiac ventricles to simulate pressure-volume dynamics in the heart. This cardiac model was integrated into a simple model of the circulation to investigate the effects of metabolic state on whole-body function. Simulations predict that reductions in metabolite pools observed in canine models of heart failure can cause systolic dysfunction, blood volume expansion, venous congestion, and ventricular dilation. Simulations also predict that myosin-activating drugs may partially counteract the effects of energetic state on cross-bridge mechanics in heart failure while increasing myocardial oxygen consumption. Our model analysis demonstrates how metabolic changes observed in heart failure are alone sufficient to cause systolic dysfunction and whole-body heart failure symptoms.
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Affiliation(s)
- Shivendra G Tewari
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, United States
| | - Scott M Bugenhagen
- Department of Physiology, Medical College of Wisconsin, 8701 Watertown Plank Rd, Milwaukee, WI 53226, United States
| | - Kalyan C Vinnakota
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, United States
| | - J Jeremy Rice
- Functional Genomics and Systems Biology Group, IBM T.J. Watson Research Center, New York, United States
| | - Paul M L Janssen
- Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH 43210, United States
| | - Daniel A Beard
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, United States.
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