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Murtha LA, Hardy SA, Mabotuwana NS, Bigland MJ, Bailey T, Raguram K, Liu S, Ngo DT, Sverdlov AL, Tomin T, Birner-Gruenberger R, Hume RD, Iismaa SE, Humphreys DT, Patrick R, Chong JJH, Lee RJ, Harvey RP, Graham RM, Rainer PP, Boyle AJ. Fibulin-3 is necessary to prevent cardiac rupture following myocardial infarction. Sci Rep 2023; 13:14995. [PMID: 37696945 PMCID: PMC10495317 DOI: 10.1038/s41598-023-41894-9] [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: 06/13/2023] [Accepted: 09/01/2023] [Indexed: 09/13/2023] Open
Abstract
Despite the high prevalence of heart failure in the western world, there are few effective treatments. Fibulin-3 is a protein involved in extracellular matrix (ECM) structural integrity, however its role in the heart is unknown. We have demonstrated, using single cell RNA-seq, that fibulin-3 was highly expressed in quiescent murine cardiac fibroblasts, with expression highest prior to injury and late post-infarct (from ~ day-28 to week-8). In humans, fibulin-3 was upregulated in left ventricular tissue and plasma of heart failure patients. Fibulin-3 knockout (Efemp1-/-) and wildtype mice were subjected to experimental myocardial infarction. Fibulin-3 deletion resulted in significantly higher rate of cardiac rupture days 3-6 post-infarct, indicating a weak and poorly formed scar, with severe ventricular remodelling in surviving mice at day-28 post-infarct. Fibulin-3 knockout mice demonstrated less collagen deposition at day-3 post-infarct, with abnormal collagen fibre-alignment. RNA-seq on day-3 infarct tissue revealed upregulation of ECM degradation and inflammatory genes, but downregulation of ECM assembly/structure/organisation genes in fibulin-3 knockout mice. GSEA pathway analysis showed enrichment of inflammatory pathways and a depletion of ECM organisation pathways. Fibulin-3 originates from cardiac fibroblasts, is upregulated in human heart failure, and is necessary for correct ECM organisation/structural integrity of fibrotic tissue to prevent cardiac rupture post-infarct.
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Affiliation(s)
- Lucy A Murtha
- Faculty of Health and Medicine, The University of Newcastle, Newcastle, NSW, Australia
- Hunter Medical Research Institute, Newcastle, NSW, 2305, Australia
| | - Sean A Hardy
- Faculty of Health and Medicine, The University of Newcastle, Newcastle, NSW, Australia
- Hunter Medical Research Institute, Newcastle, NSW, 2305, Australia
| | - Nishani S Mabotuwana
- Faculty of Health and Medicine, The University of Newcastle, Newcastle, NSW, Australia
- Hunter Medical Research Institute, Newcastle, NSW, 2305, Australia
| | - Mark J Bigland
- Faculty of Health and Medicine, The University of Newcastle, Newcastle, NSW, Australia
- Hunter Medical Research Institute, Newcastle, NSW, 2305, Australia
| | - Taleah Bailey
- Faculty of Health and Medicine, The University of Newcastle, Newcastle, NSW, Australia
- Hunter Medical Research Institute, Newcastle, NSW, 2305, Australia
| | - Kalyan Raguram
- Faculty of Health and Medicine, The University of Newcastle, Newcastle, NSW, Australia
- Hunter Medical Research Institute, Newcastle, NSW, 2305, Australia
| | - Saifei Liu
- Department of Cardiology and Clinical Pharmacology, Basil Hetzel Institute, The University of Adelaide, The Queen Elizabeth Hospital, Adelaide, SA, Australia
| | - Doan T Ngo
- Faculty of Health and Medicine, The University of Newcastle, Newcastle, NSW, Australia
- Hunter Medical Research Institute, Newcastle, NSW, 2305, Australia
- Department of Cardiology and Clinical Pharmacology, Basil Hetzel Institute, The University of Adelaide, The Queen Elizabeth Hospital, Adelaide, SA, Australia
| | - Aaron L Sverdlov
- Faculty of Health and Medicine, The University of Newcastle, Newcastle, NSW, Australia
- Hunter Medical Research Institute, Newcastle, NSW, 2305, Australia
- Department of Cardiology and Clinical Pharmacology, Basil Hetzel Institute, The University of Adelaide, The Queen Elizabeth Hospital, Adelaide, SA, Australia
- Department of Cardiovascular Medicine, John Hunter Hospital, Newcastle, NSW, Australia
| | - Tamara Tomin
- Institute of Chemical Technologies and Analytics, Faculty of Technical Chemistry, Technische Universität Wien, Vienna, Austria
- Diagnostic and Research Institute of Pathology, Medical University of Graz, Graz, Austria
| | - Ruth Birner-Gruenberger
- Institute of Chemical Technologies and Analytics, Faculty of Technical Chemistry, Technische Universität Wien, Vienna, Austria
- Diagnostic and Research Institute of Pathology, Medical University of Graz, Graz, Austria
| | - Robert D Hume
- Centre for Heart Research, Westmead Institute for Medical Research, The University of Sydney, Sydney, NSW, Australia
| | - Siiri E Iismaa
- Victor Chang Cardiac Research Institute, Sydney, NSW, Australia
- St Vincent's Clinical School, UNSW, Sydney, Kensington, NSW, Australia
| | - David T Humphreys
- Victor Chang Cardiac Research Institute, Sydney, NSW, Australia
- St Vincent's Clinical School, UNSW, Sydney, Kensington, NSW, Australia
| | - Ralph Patrick
- Victor Chang Cardiac Research Institute, Sydney, NSW, Australia
- St Vincent's Clinical School, UNSW, Sydney, Kensington, NSW, Australia
| | - James J H Chong
- Centre for Heart Research, Westmead Institute for Medical Research, The University of Sydney, Sydney, NSW, Australia
- Department of Cardiology, Westmead Hospital, Sydney, NSW, Australia
- Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia
| | - Randall J Lee
- Department of Medicine, Division of Cardiology, University of California San Francisco, San Francisco, CA, USA
- Edyth and Eli Broad Center for Regenerative Medicine and Stem Cell Research, University of California San Francisco, San Francisco, CA, USA
- Cardiovascular Research Institute, University of California San Francisco, San Francisco, CA, USA
| | - Richard P Harvey
- Victor Chang Cardiac Research Institute, Sydney, NSW, Australia
- St Vincent's Clinical School, UNSW, Sydney, Kensington, NSW, Australia
- School of Biotechnology and Molecular Bioscience, UNSW, Sydney, Kensington, NSW, Australia
| | - Robert M Graham
- Victor Chang Cardiac Research Institute, Sydney, NSW, Australia
- St Vincent's Clinical School, UNSW, Sydney, Kensington, NSW, Australia
| | - Peter P Rainer
- Division of Cardiology, Medical University of Graz, Graz, Austria
- BioTechMed Graz, Graz, Austria
| | - Andrew J Boyle
- Faculty of Health and Medicine, The University of Newcastle, Newcastle, NSW, Australia.
- Hunter Medical Research Institute, Newcastle, NSW, 2305, Australia.
- Department of Cardiovascular Medicine, John Hunter Hospital, Newcastle, NSW, Australia.
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Baghersad S, Sathish Kumar A, Kipper MJ, Popat K, Wang Z. Recent Advances in Tissue-Engineered Cardiac Scaffolds-The Progress and Gap in Mimicking Native Myocardium Mechanical Behaviors. J Funct Biomater 2023; 14:jfb14050269. [PMID: 37233379 DOI: 10.3390/jfb14050269] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Revised: 05/04/2023] [Accepted: 05/06/2023] [Indexed: 05/27/2023] Open
Abstract
Heart failure is the leading cause of death in the US and worldwide. Despite modern therapy, challenges remain to rescue the damaged organ that contains cells with a very low proliferation rate after birth. Developments in tissue engineering and regeneration offer new tools to investigate the pathology of cardiac diseases and develop therapeutic strategies for heart failure patients. Tissue -engineered cardiac scaffolds should be designed to provide structural, biochemical, mechanical, and/or electrical properties similar to native myocardium tissues. This review primarily focuses on the mechanical behaviors of cardiac scaffolds and their significance in cardiac research. Specifically, we summarize the recent development of synthetic (including hydrogel) scaffolds that have achieved various types of mechanical behavior-nonlinear elasticity, anisotropy, and viscoelasticity-all of which are characteristic of the myocardium and heart valves. For each type of mechanical behavior, we review the current fabrication methods to enable the biomimetic mechanical behavior, the advantages and limitations of the existing scaffolds, and how the mechanical environment affects biological responses and/or treatment outcomes for cardiac diseases. Lastly, we discuss the remaining challenges in this field and suggestions for future directions to improve our understanding of mechanical control over cardiac function and inspire better regenerative therapies for myocardial restoration.
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Affiliation(s)
- Somayeh Baghersad
- School of Biomedical Engineering, Colorado State University, Fort Collins, CO 80523, USA
| | - Abinaya Sathish Kumar
- School of Biomedical Engineering, Colorado State University, Fort Collins, CO 80523, USA
| | - Matt J Kipper
- School of Biomedical Engineering, Colorado State University, Fort Collins, CO 80523, USA
- Department of Chemical and Biological Engineering, Colorado State University, Fort Collins, CO 80523, USA
- School of Materials Science and Engineering, Colorado State University, Fort Collins, CO 80523, USA
| | - Ketul Popat
- School of Biomedical Engineering, Colorado State University, Fort Collins, CO 80523, USA
- School of Materials Science and Engineering, Colorado State University, Fort Collins, CO 80523, USA
- Department of Mechanical Engineering, Colorado State University, Fort Collins, CO 80523, USA
| | - Zhijie Wang
- School of Biomedical Engineering, Colorado State University, Fort Collins, CO 80523, USA
- Department of Mechanical Engineering, Colorado State University, Fort Collins, CO 80523, USA
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3
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Ghanta RK, Pugazenthi A, Zhao Y, Sylvester C, Wall MJ, Mazur RA, Russell LN, Lampe KJ. Influence of Supraphysiologic Biomaterial Stiffness on Ventricular Mechanics and Myocardial Infarct Reinforcement. Acta Biomater 2022; 149:30-39. [PMID: 35820592 DOI: 10.1016/j.actbio.2022.07.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Revised: 07/02/2022] [Accepted: 07/05/2022] [Indexed: 11/15/2022]
Abstract
Injectable intramyocardial biomaterials have promise to limit adverse ventricular remodeling through mechanical and biologic mechanisms. While some success has been observed by injecting materials to regenerate new tissue, optimal biomaterial stiffness to thicken and stiffen infarcted myocardium to limit adverse remodeling has not been determined. In this work, we present an in-vivo study of the impact of biomaterial stiffness over a wide range of stiffness moduli on ventricular mechanics. We utilized injectable methacrylated polyethylene glycol (PEG) hydrogels fabricated at 3 different mechanical moduli: 5 kPa (low), 25 kPa (medium/myocardium), and 250 kPa (high/supraphysiologic). We demonstrate that the supraphysiological high stiffness favorably alters post-infarct ventricular mechanics and prevents negative tissue remodeling. Lower stiffness materials do not alter mechanics and thus to be effective, must instead target biological reparative mechanisms. These results may influence rationale design criteria for biomaterials developed for infarct reinforcement therapy. STATEMENT OF SIGNIFICANCE: Acellular biomaterials for cardiac application can provide benefit via mechanical and biological mechanisms post myocardial infarction. We study the role of biomaterial mechanical characteristics on ventricular mechanics in myocardial infarcts. Previous studies have not measured the influence of injected biomaterials on ventricular mechanics, and consequently rational design criteria is unknown. By utilizing an in-vivo assessment of ventricular mechanics, we demonstrate that low stiffness biomaterial do not alter pathologic ventricular mechanics. Thus, to be effective, low stiffness biomaterials must target biological reparative mechanisms. Physiologic and supra-physiologic biomaterials favorably alter post-infarct mechanics and prevents adverse ventricular remodeling.
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Affiliation(s)
- Ravi K Ghanta
- Michael E. DeBakey Department of Surgery, Baylor College of Medicine, Houston, TX United States; Department of Cardiovascular Surgery, Texas Heart Institute, Houston, TX United States.
| | - Aarthi Pugazenthi
- Michael E. DeBakey Department of Surgery, Baylor College of Medicine, Houston, TX United States
| | - Yunge Zhao
- Department of Surgery, University of Maryland, Baltimore, MD United States
| | - Christopher Sylvester
- Michael E. DeBakey Department of Surgery, Baylor College of Medicine, Houston, TX United States; Medical Scientist Training Program, Baylor College of Medicine, Houston, TX United States
| | - Mathew J Wall
- Michael E. DeBakey Department of Surgery, Baylor College of Medicine, Houston, TX United States
| | - Rachel A Mazur
- Department of Chemical Engineering, University of Virginia, Charlottesville, VA United States
| | - Lauren N Russell
- Department of Chemical Engineering, University of Virginia, Charlottesville, VA United States
| | - Kyle J Lampe
- Department of Chemical Engineering, University of Virginia, Charlottesville, VA United States
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Wang H, Wisneski A, Imbrie-Moore AM, Paulsen MJ, Wang Z, Xuan Y, Lopez Hernandez H, Hironaka CE, Lucian HJ, Shin HS, Anilkumar S, Thakore AD, Farry JM, Eskandari A, Williams KM, Grady F, Wu MA, Jung J, Stapleton LM, Steele AN, Zhu Y, Woo YJ. Natural cardiac regeneration conserves native biaxial left ventricular biomechanics after myocardial infarction in neonatal rats. J Mech Behav Biomed Mater 2022; 126:105074. [PMID: 35030471 PMCID: PMC8899021 DOI: 10.1016/j.jmbbm.2022.105074] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 12/23/2021] [Accepted: 01/02/2022] [Indexed: 02/03/2023]
Abstract
After myocardial infarction (MI), adult mammals exhibit scar formation, adverse left ventricular (LV) remodeling, LV stiffening, and impaired contractility, ultimately resulting in heart failure. Neonatal mammals, however, are capable of natural heart regeneration after MI. We hypothesized that neonatal cardiac regeneration conserves native biaxial LV mechanics after MI. Wistar rat neonates (1 day old, n = 46) and adults (8-10 weeks old, n = 20) underwent sham surgery or permanent left anterior descending coronary artery ligation. At 6 weeks after neonatal MI, Masson's trichrome staining revealed negligible fibrosis. Echocardiography for the neonatal MI (n = 15) and sham rats (n = 14) revealed no differences in LV wall thickness or chamber diameter, and both groups had normal ejection fraction (72.7% vs 77.5%, respectively, p = 0.1946). Biaxial tensile testing revealed similar stress-strain curves along both the circumferential and longitudinal axes across a full range of physiologic stresses and strains. The circumferential modulus (267.9 kPa vs 274.2 kPa, p = 0.7847), longitudinal modulus (269.3 kPa vs 277.1 kPa, p = 0.7435), and maximum shear stress (3.30 kPa vs 3.95 kPa, p = 0.5418) did not differ significantly between the neonatal MI and sham groups, respectively. In contrast, transmural scars were observed at 4 weeks after adult MI. Adult MI hearts (n = 7) exhibited profound LV wall thinning (p < 0.0001), chamber dilation (p = 0.0246), and LV dysfunction (ejection fraction 45.4% vs 79.7%, p < 0.0001) compared to adult sham hearts (n = 7). Adult MI hearts were significantly stiffer than adult sham hearts in both the circumferential (321.5 kPa vs 180.0 kPa, p = 0.0111) and longitudinal axes (315.4 kPa vs 172.3 kPa, p = 0.0173), and also exhibited greater maximum shear stress (14.87 kPa vs 3.23 kPa, p = 0.0162). Our study is the first to show that native biaxial LV mechanics are conserved after neonatal heart regeneration following MI, thus adding biomechanical support for the therapeutic potential of cardiac regeneration in the treatment of ischemic heart disease.
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Affiliation(s)
- Hanjay Wang
- Department of Cardiothoracic Surgery, Stanford University, Stanford, CA, USA; Stanford Cardiovascular Institute, Stanford University, Stanford, CA, USA
| | - Andrew Wisneski
- Department of Surgery, University of California San Francisco, San Francisco, CA, USA
| | - Annabel M Imbrie-Moore
- Department of Cardiothoracic Surgery, Stanford University, Stanford, CA, USA; Department of Mechanical Engineering, Stanford University, Stanford, CA, USA
| | - Michael J Paulsen
- Department of Cardiothoracic Surgery, Stanford University, Stanford, CA, USA
| | - Zhongjie Wang
- Department of Surgery, University of California San Francisco, San Francisco, CA, USA
| | - Yue Xuan
- Department of Surgery, University of California San Francisco, San Francisco, CA, USA
| | | | - Camille E Hironaka
- Department of Cardiothoracic Surgery, Stanford University, Stanford, CA, USA
| | - Haley J Lucian
- Department of Cardiothoracic Surgery, Stanford University, Stanford, CA, USA
| | - Hye Sook Shin
- Department of Cardiothoracic Surgery, Stanford University, Stanford, CA, USA
| | - Shreya Anilkumar
- Department of Cardiothoracic Surgery, Stanford University, Stanford, CA, USA
| | - Akshara D Thakore
- Department of Cardiothoracic Surgery, Stanford University, Stanford, CA, USA
| | - Justin M Farry
- Department of Cardiothoracic Surgery, Stanford University, Stanford, CA, USA
| | - Anahita Eskandari
- Department of Cardiothoracic Surgery, Stanford University, Stanford, CA, USA
| | - Kiah M Williams
- Department of Cardiothoracic Surgery, Stanford University, Stanford, CA, USA
| | - Frederick Grady
- Department of Cardiothoracic Surgery, Stanford University, Stanford, CA, USA
| | - Matthew A Wu
- Department of Cardiothoracic Surgery, Stanford University, Stanford, CA, USA
| | - Jinsuh Jung
- Department of Cardiothoracic Surgery, Stanford University, Stanford, CA, USA
| | - Lyndsay M Stapleton
- Department of Cardiothoracic Surgery, Stanford University, Stanford, CA, USA; Department of Bioengineering, Stanford University, Stanford, CA, USA
| | - Amanda N Steele
- Department of Cardiothoracic Surgery, Stanford University, Stanford, CA, USA; Department of Bioengineering, Stanford University, Stanford, CA, USA
| | - Yuanjia Zhu
- Department of Cardiothoracic Surgery, Stanford University, Stanford, CA, USA; Department of Bioengineering, Stanford University, Stanford, CA, USA
| | - Y Joseph Woo
- Department of Cardiothoracic Surgery, Stanford University, Stanford, CA, USA; Stanford Cardiovascular Institute, Stanford University, Stanford, CA, USA; Department of Bioengineering, Stanford University, Stanford, CA, USA.
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5
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Pluripotent stem cell-derived mesenchymal stromal cells improve cardiac function and vascularity after myocardial infarction. Cytotherapy 2021; 23:1074-1084. [PMID: 34588150 DOI: 10.1016/j.jcyt.2021.07.016] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Revised: 07/27/2021] [Accepted: 07/28/2021] [Indexed: 01/10/2023]
Abstract
BACKGROUND AIMS Mesenchymal stromal cells (MSCs) have been shown to improve cardiac function after injury and are the subject of ongoing clinical trials. In this study, the authors tested the cardiac regenerative potential of an induced pluripotent stem cell-derived MSC (iPSC-MSC) population (Cymerus MSCs) in a rat model of myocardial ischemia-reperfusion (I/R). Furthermore, the authors compared this efficacy with bone marrow-derived MSCs (BM-MSCs), which are the predominant cell type in clinical trials. METHODS Four days after myocardial I/R injury, rats were randomly assigned to (i) a Cymerus MSC group (n = 15), (ii) a BM-MSC group (n = 15) or (iii) a vehicle control group (n = 14). For cell-treated animals, a total of 5 × 106 cells were injected at three sites within the infarcted left ventricular (LV) wall. RESULTS One month after cell transplantation, Cymerus MSCs improved LV function (assessed by echocardiography) compared with vehicle and BM-MSCs. Interestingly, Cymerus MSCs enhanced angiogenesis without sustained engraftment or significant impact on infarct scar size. Suggesting safety, Cymerus MSCs had no effect on inducible tachycardia or the ventricular scar heterogeneity that provides a substrate for cardiac re-entrant circuits. CONCLUSIONS The authors here demonstrate that intra-myocardial administration of iPSC-MSCs (Cymerus MSCs) provide better therapeutic effects compared with conventional BM-MSCs in a rodent model of myocardial I/R. Because of its manufacturing scalability, iPSC-MSC therapy offers an exciting opportunity for an "off-the-shelf" stem cell therapy for cardiac repair.
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6
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Caggiano LR, Holmes JW. A Comparison of Fiber Based Material Laws for Myocardial Scar. JOURNAL OF ELASTICITY 2021; 145:321-337. [PMID: 35095176 PMCID: PMC8797542 DOI: 10.1007/s10659-021-09845-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Accepted: 06/10/2021] [Indexed: 06/14/2023]
Abstract
The mechanics of most soft tissues in the human body are determined by the organization of their collagen fibers. Predicting how mechanics will change during growth and remodeling of those tissues requires constitutive laws that account for the density and dispersion of collagen fibers. Post-infarction scar in the heart, a mechanically and structurally complex material, does not yet have a validated fiber-based constitutive model. In this study, we tested four different constitutive laws employing exponential or polynomial strain-energy functions and accounting for either mean fiber orientation alone or the details of the fiber distribution about that mean. We quantified the goodness of fit of each law to mechanical testing data from 6-week-old myocardial scar in the rat using both sum of squared error (SSE) and the Akaike Information Criterion (AIC) to account for differences in the number of material parameters within the constitutive laws. We then compared their ability to prospectively predict the mechanics of independent myocardial scar samples from other time points during healing. Our analysis suggests that a constitutive law with a polynomial form that incorporates detailed information about collagen fiber distribution using a structure tensor provides excellent fits with just two parameters and reasonable predictions of myocardial scar mechanics from measured structure alone in scars containing sufficiently high collagen content.
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Affiliation(s)
- Laura R. Caggiano
- Department of Biomedical Engineering, University of Virginia, Charlottesville, VA, USA
| | - Jeffrey W. Holmes
- Department of Biomedical Engineering, University of Virginia, Charlottesville, VA, USA
- School of Engineering, University of Alabama at Birmingham, Birmingham, AL, USA
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7
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Dwyer KD, Coulombe KL. Cardiac mechanostructure: Using mechanics and anisotropy as inspiration for developing epicardial therapies in treating myocardial infarction. Bioact Mater 2021; 6:2198-2220. [PMID: 33553810 PMCID: PMC7822956 DOI: 10.1016/j.bioactmat.2020.12.015] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 12/18/2020] [Accepted: 12/18/2020] [Indexed: 12/14/2022] Open
Abstract
The mechanical environment and anisotropic structure of the heart modulate cardiac function at the cellular, tissue and organ levels. During myocardial infarction (MI) and subsequent healing, however, this landscape changes significantly. In order to engineer cardiac biomaterials with the appropriate properties to enhance function after MI, the changes in the myocardium induced by MI must be clearly identified. In this review, we focus on the mechanical and structural properties of the healthy and infarcted myocardium in order to gain insight about the environment in which biomaterial-based cardiac therapies are expected to perform and the functional deficiencies caused by MI that the therapy must address. From this understanding, we discuss epicardial therapies for MI inspired by the mechanics and anisotropy of the heart focusing on passive devices, which feature a biomaterials approach, and active devices, which feature robotic and cellular components. Through this review, a detailed analysis is provided in order to inspire further development and translation of epicardial therapies for MI.
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Affiliation(s)
- Kiera D. Dwyer
- Center for Biomedical Engineering, School of Engineering, Brown University, Providence, RI, USA
| | - Kareen L.K. Coulombe
- Center for Biomedical Engineering, School of Engineering, Brown University, Providence, RI, USA
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8
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Thavapalachandran S, Grieve SM, Hume RD, Le TYL, Raguram K, Hudson JE, Pouliopoulos J, Figtree GA, Dye RP, Barry AM, Brown P, Lu J, Coffey S, Kesteven SH, Mills RJ, Rashid FN, Taran E, Kovoor P, Thomas L, Denniss AR, Kizana E, Asli NS, Xaymardan M, Feneley MP, Graham RM, Harvey RP, Chong JJH. Platelet-derived growth factor-AB improves scar mechanics and vascularity after myocardial infarction. Sci Transl Med 2021; 12:12/524/eaay2140. [PMID: 31894101 DOI: 10.1126/scitranslmed.aay2140] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Accepted: 11/06/2019] [Indexed: 12/13/2022]
Abstract
Therapies that target scar formation after myocardial infarction (MI) could prevent ensuing heart failure or death from ventricular arrhythmias. We have previously shown that recombinant human platelet-derived growth factor-AB (rhPDGF-AB) improves cardiac function in a rodent model of MI. To progress clinical translation, we evaluated rhPDGF-AB treatment in a clinically relevant porcine model of myocardial ischemia-reperfusion. Thirty-six pigs were randomized to sham procedure or balloon occlusion of the proximal left anterior descending coronary artery with 7-day intravenous infusion of rhPDGF-AB or vehicle. One month after MI, rhPDGF-AB improved survival by 40% compared with vehicle, and cardiac magnetic resonance imaging showed left ventricular (LV) ejection fraction improved by 11.5%, driven by reduced LV end-systolic volumes. Pressure volume loop analyses revealed improved myocardial contractility and energetics after rhPDGF-AB treatment with minimal effect on ventricular compliance. rhPDGF-AB enhanced angiogenesis and increased scar anisotropy (high fiber alignment) without affecting overall scar size or stiffness. rhPDGF-AB reduced inducible ventricular tachycardia by decreasing heterogeneity of the ventricular scar that provides a substrate for reentrant circuits. In summary, we demonstrated that rhPDGF-AB promotes post-MI cardiac wound repair by altering the mechanics of the infarct scar, resulting in robust cardiac functional improvement, decreased ventricular arrhythmias, and improved survival. Our findings suggest a strong translational potential for rhPDGF-AB as an adjunct to current MI treatment and possibly to modulate scar in other organs.
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Affiliation(s)
- Sujitha Thavapalachandran
- Centre for Heart Research, Westmead Institute for Medical Research, The University of Sydney, Westmead, NSW 2145, Australia.,Department of Cardiology, Westmead Hospital, Westmead, NSW 2145, Australia
| | - Stuart M Grieve
- Sydney Translational Imaging Laboratory, Heart Research Institute, Charles Perkins Centre, The University of Sydney, Sydney, NSW 2006, Australia
| | - Robert D Hume
- Centre for Heart Research, Westmead Institute for Medical Research, The University of Sydney, Westmead, NSW 2145, Australia
| | - Thi Yen Loan Le
- Centre for Heart Research, Westmead Institute for Medical Research, The University of Sydney, Westmead, NSW 2145, Australia
| | - Kalyan Raguram
- Centre for Heart Research, Westmead Institute for Medical Research, The University of Sydney, Westmead, NSW 2145, Australia
| | - James E Hudson
- QIMR Berghofer Medical Research Institute, Brisbane, QLD 4006, Australia
| | - Jim Pouliopoulos
- Department of Cardiology, Westmead Hospital, Westmead, NSW 2145, Australia
| | - Gemma A Figtree
- Kolling Institute of Medical Research, The University of Sydney, Royal North Shore Hospital, St Leonards, NSW 2065, Australia
| | - Rafael P Dye
- Kolling Institute of Medical Research, The University of Sydney, Royal North Shore Hospital, St Leonards, NSW 2065, Australia
| | - Anthony M Barry
- Department of Cardiology, Westmead Hospital, Westmead, NSW 2145, Australia
| | - Paula Brown
- Department of Cardiology, Westmead Hospital, Westmead, NSW 2145, Australia
| | - Juntang Lu
- Department of Cardiology, Westmead Hospital, Westmead, NSW 2145, Australia
| | - Sean Coffey
- Kolling Institute of Medical Research, The University of Sydney, Royal North Shore Hospital, St Leonards, NSW 2065, Australia.,Department of Medicine, Dunedin School of Medicine, Dunedin Hospital, Dunedin 9016, New Zealand
| | - Scott H Kesteven
- Victor Chang Cardiac Research Institute, Darlinghurst, NSW 2010, Australia
| | - Richard J Mills
- QIMR Berghofer Medical Research Institute, Brisbane, QLD 4006, Australia
| | - Fairooj N Rashid
- Centre for Heart Research, Westmead Institute for Medical Research, The University of Sydney, Westmead, NSW 2145, Australia
| | - Elena Taran
- Australian National Fabrication Facility-Queensland Node, The University of Queensland, St. Lucia, QLD 4072, Australia.,School of Chemical Engineering, University of Melbourne, VIC 3010, Australia
| | - Pramesh Kovoor
- Department of Cardiology, Westmead Hospital, Westmead, NSW 2145, Australia
| | - Liza Thomas
- Department of Cardiology, Westmead Hospital, Westmead, NSW 2145, Australia
| | | | - Eddy Kizana
- Centre for Heart Research, Westmead Institute for Medical Research, The University of Sydney, Westmead, NSW 2145, Australia.,Department of Cardiology, Westmead Hospital, Westmead, NSW 2145, Australia
| | - Naisana S Asli
- Victor Chang Cardiac Research Institute, Darlinghurst, NSW 2010, Australia.,Faculty of Medicine and Health, University of Sydney, Westmead Hospital, Westmead, NSW 2145, Australia.,Centre for Cancer Research, The Westmead Institute for Medical Research, Sydney, NSW 2145, Australia
| | - Munira Xaymardan
- Victor Chang Cardiac Research Institute, Darlinghurst, NSW 2010, Australia
| | - Michael P Feneley
- Victor Chang Cardiac Research Institute, Darlinghurst, NSW 2010, Australia.,St. Vincent's Clinical School, UNSW Sydney, Kensington, NSW 2052, Australia
| | - Robert M Graham
- Victor Chang Cardiac Research Institute, Darlinghurst, NSW 2010, Australia.,St. Vincent's Clinical School, UNSW Sydney, Kensington, NSW 2052, Australia
| | - Richard P Harvey
- Victor Chang Cardiac Research Institute, Darlinghurst, NSW 2010, Australia.,St. Vincent's Clinical School, UNSW Sydney, Kensington, NSW 2052, Australia.,School of Biotechnology and Biomolecular Science, UNSW Sydney, Kensington, NSW 2052, Australia
| | - James J H Chong
- Centre for Heart Research, Westmead Institute for Medical Research, The University of Sydney, Westmead, NSW 2145, Australia. .,Department of Cardiology, Westmead Hospital, Westmead, NSW 2145, Australia
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9
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Wang H, Bennett-Kennett R, Paulsen MJ, Hironaka CE, Thakore AD, Farry JM, Eskandari A, Lucian HJ, Shin HS, Wu MA, Imbrie-Moore AM, Steele AN, Stapleton LM, Zhu Y, Dauskardt RH, Woo YJ. Multiaxial Lenticular Stress-Strain Relationship of Native Myocardium is Preserved by Infarct-Induced Natural Heart Regeneration in Neonatal Mice. Sci Rep 2020; 10:7319. [PMID: 32355240 PMCID: PMC7193551 DOI: 10.1038/s41598-020-63324-w] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Accepted: 03/13/2020] [Indexed: 12/16/2022] Open
Abstract
Neonatal mice exhibit natural heart regeneration after myocardial infarction (MI) on postnatal day 1 (P1), but this ability is lost by postnatal day 7 (P7). Cardiac biomechanics intricately affect long-term heart function, but whether regenerated cardiac muscle is biomechanically similar to native myocardium remains unknown. We hypothesized that neonatal heart regeneration preserves native left ventricular (LV) biomechanical properties after MI. C57BL/6J mice underwent sham surgery or left anterior descending coronary artery ligation at age P1 or P7. Echocardiography performed 4 weeks post-MI showed that P1 MI and sham mice (n = 22, each) had similar LV wall thickness, diameter, and ejection fraction (59.6% vs 60.7%, p = 0.6514). Compared to P7 shams (n = 20), P7 MI mice (n = 20) had significant LV wall thinning, chamber enlargement, and depressed ejection fraction (32.6% vs 61.8%, p < 0.0001). Afterward, the LV was explanted and pressurized ex vivo, and the multiaxial lenticular stress-strain relationship was tracked. While LV tissue modulus for P1 MI and sham mice were similar (341.9 kPa vs 363.4 kPa, p = 0.6140), the modulus for P7 MI mice was significantly greater than that for P7 shams (691.6 kPa vs 429.2 kPa, p = 0.0194). We conclude that, in neonatal mice, regenerated LV muscle has similar biomechanical properties as native LV myocardium.
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Affiliation(s)
- Hanjay Wang
- Department of Cardiothoracic Surgery, Stanford University, Stanford, CA, USA
- Stanford Cardiovascular Institute, Stanford University, Stanford, CA, USA
| | - Ross Bennett-Kennett
- Department of Materials Science and Engineering, Stanford University, Stanford, CA, USA
| | - Michael J Paulsen
- Department of Cardiothoracic Surgery, Stanford University, Stanford, CA, USA
| | - Camille E Hironaka
- Department of Cardiothoracic Surgery, Stanford University, Stanford, CA, USA
| | - Akshara D Thakore
- Department of Cardiothoracic Surgery, Stanford University, Stanford, CA, USA
| | - Justin M Farry
- Department of Cardiothoracic Surgery, Stanford University, Stanford, CA, USA
| | - Anahita Eskandari
- Department of Cardiothoracic Surgery, Stanford University, Stanford, CA, USA
| | - Haley J Lucian
- Department of Cardiothoracic Surgery, Stanford University, Stanford, CA, USA
| | - Hye Sook Shin
- Department of Cardiothoracic Surgery, Stanford University, Stanford, CA, USA
| | - Matthew A Wu
- Department of Cardiothoracic Surgery, Stanford University, Stanford, CA, USA
| | - Annabel M Imbrie-Moore
- Department of Cardiothoracic Surgery, Stanford University, Stanford, CA, USA
- Department of Mechanical Engineering, Stanford University, Stanford, CA, USA
| | - Amanda N Steele
- Department of Cardiothoracic Surgery, Stanford University, Stanford, CA, USA
- Department of Bioengineering, Stanford University, Stanford, CA, USA
| | - Lyndsay M Stapleton
- Department of Cardiothoracic Surgery, Stanford University, Stanford, CA, USA
- Department of Bioengineering, Stanford University, Stanford, CA, USA
| | - Yuanjia Zhu
- Department of Cardiothoracic Surgery, Stanford University, Stanford, CA, USA
- Department of Bioengineering, Stanford University, Stanford, CA, USA
| | - Reinhold H Dauskardt
- Department of Materials Science and Engineering, Stanford University, Stanford, CA, USA
| | - Y Joseph Woo
- Department of Cardiothoracic Surgery, Stanford University, Stanford, CA, USA.
- Stanford Cardiovascular Institute, Stanford University, Stanford, CA, USA.
- Department of Bioengineering, Stanford University, Stanford, CA, USA.
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10
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Korenczuk CE, Barocas VH, Richardson WJ. Effects of Collagen Heterogeneity on Myocardial Infarct Mechanics in a Multiscale Fiber Network Model. J Biomech Eng 2019; 141:091015. [PMID: 31141605 PMCID: PMC6807994 DOI: 10.1115/1.4043865] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2019] [Revised: 05/23/2019] [Indexed: 01/14/2023]
Abstract
The scar that forms after a myocardial infarction is often characterized by a highly disordered architecture but generally exhibits some degree of collagen fiber orientation, with a resulting mechanical anisotropy. When viewed in finer detail, however, the heterogeneity of the sample is clear, with different subregions exhibiting different fiber orientations. In this work, we used a multiscale finite element model to explore the consequences of the heterogeneity in terms of mechanical behavior. To do so, we used previously obtained fiber alignment maps of rat myocardial scar slices (n = 15) to generate scar-specific finite element meshes that were populated with fiber models based on the local alignment state. These models were then compared to isotropic models with the same sample shape and fiber density, and to homogeneous models with the same sample shape, fiber density, and average fiber alignment as the scar-specific models. All simulations involved equibiaxial extension of the sample with free motion in the third dimension. We found that heterogeneity led to a lower degree of mechanical anisotropy and a higher level of local stress concentration than the corresponding homogeneous model, and also that fibers failed in the heterogeneous model at much lower macroscopic strains than in the isotropic and homogeneous models. Taken together, these results suggest that scar heterogeneity may impair myocardial mechanical function both in terms of anisotropy and strength, and that individual variations in scar heterogeneity could be an important consideration for understanding scar remodeling and designing therapeutic interventions for patients after myocardial infarction.
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Affiliation(s)
- Christopher E Korenczuk
- Department of Biomedical Engineering,University of Minnesota,7-105 Nils Hasselmo Hall,312 Church Street SE,Minneapolis, MN 55455e-mail:
| | - Victor H Barocas
- Department of Biomedical Engineering,University of Minnesota,7-105 Nils Hasselmo Hall,312 Church Street SE,Minneapolis, MN 55455e-mail:
| | - William J Richardson
- Department of Bioengineering,Clemson University,401-3 Rhodes Engineering Research Center,118 Engineering Service Drive,Clemson, SC 29631e-mail:
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11
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Witzenburg C, Holmes JW. The Impact of Hemodynamic Reflex Compensation Following Myocardial Infarction on Subsequent Ventricular Remodeling. J Biomech Eng 2019; 141:2735313. [PMID: 31141599 DOI: 10.1115/1.4043867] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Indexed: 01/05/2023]
Abstract
Patients who survive a myocardial infarction (MI) are at risk for ventricular dilation and heart failure. While infarct size is an important determinant of post-MI remodeling, different patients with the same size infarct often display different levels of left ventricular (LV) dilation. The acute physiologic response to MI involves reflex compensation, whereby increases in heart rate, arterial resistance, venoconstriction, and contractility of the surviving myocardium act to maintain mean arterial pressure. We hypothesized that variability in compensation might underlie some of the reported variability in post-MI remodeling, a hypothesis that is difficult to test using experimental data alone because some responses are difficult or impossible to measure directly. We therefore employed a computational model to estimate the balance of compensatory mechanisms from experimentally reported hemodynamic data. We found a strikingly wide range of compensatory reflex profiles in response to MI in dogs and verified that pharmacologic blockade of sympathetic and parasympathetic reflexes nearly abolished this variability. Then, using a previously published model of post-infarction remodeling, we showed that observed variability in compensation translated to variability in predicted LV dilation consistent with published data. Treatment with a vasodilator shifted the compensatory response away from arterial and venous vasoconstriction and towards increased heart rate and myocardial contractility. Importantly, this shift reduced predicted dilation, a prediction that matched prior experimental studies. Thus, post-infarction reflex compensation could represent both a source of individual variability in the extent of LV remodeling and a target for therapies aimed at reducing that remodeling.
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Affiliation(s)
| | - Jeffrey W Holmes
- Biomedical Engineering, Medicine, Robert M. Berne Cardiovascular Research Center, and Center for Engineering in Medicine, University of Virginia, Charlottesville, VA, USA
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12
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Wang H, Wisneski A, Paulsen MJ, Imbrie-Moore A, Wang Z, Xuan Y, Hernandez HL, Lucian HJ, Eskandari A, Thakore AD, Farry JM, Hironaka CE, von Bornstaedt D, Steele AN, Stapleton LM, Williams KM, Wu MA, MacArthur JW, Woo YJ. Bioengineered analog of stromal cell-derived factor 1α preserves the biaxial mechanical properties of native myocardium after infarction. J Mech Behav Biomed Mater 2019; 96:165-171. [PMID: 31035067 DOI: 10.1016/j.jmbbm.2019.04.014] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Revised: 02/04/2019] [Accepted: 04/11/2019] [Indexed: 01/08/2023]
Abstract
Adverse remodeling of the left ventricle (LV) after myocardial infarction (MI) results in abnormal tissue biomechanics and impaired cardiac function, often leading to heart failure. We hypothesized that intramyocardial delivery of engineered stromal cell-derived factor 1α analog (ESA), our previously-developed supra-efficient pro-angiogenic chemokine, preserves biaxial LV mechanical properties after MI. Male Wistar rats (n = 45) underwent sham surgery (n = 15) or permanent left anterior descending coronary artery ligation. Rats sustaining MI were randomized for intramyocardial injections of either saline (100 μL, n = 15) or ESA (6 μg/kg, n = 15), delivered at four standardized borderzone sites. After 4 weeks, echocardiography was performed, and the hearts were explanted. Tensile testing of the anterolateral LV wall was performed using a displacement-controlled biaxial load frame, and modulus was determined after constitutive modeling. At 4 weeks post-MI, compared to saline controls, ESA-treated hearts had greater wall thickness (1.68 ± 0.05 mm vs 1.42 ± 0.08 mm, p = 0.008), smaller end-diastolic LV internal dimension (6.88 ± 0.29 mm vs 7.69 ± 0.22 mm, p = 0.044), and improved ejection fraction (62.8 ± 3.0% vs 49.4 ± 4.5%, p = 0.014). Histologic analysis revealed significantly reduced infarct size for ESA-treated hearts compared to saline controls (29.4 ± 2.9% vs 41.6 ± 3.1%, p = 0.021). Infarcted hearts treated with ESA exhibited decreased modulus compared to those treated with saline in both the circumferential (211.5 ± 6.9 kPa vs 264.3 ± 12.5 kPa, p = 0.001) and longitudinal axes (194.5 ± 6.5 kPa vs 258.1 ± 14.4 kPa, p < 0.001). In both principal directions, ESA-treated infarcted hearts possessed similar tissue compliance as sham non-infarcted hearts. Overall, intramyocardial ESA therapy improves post-MI ventricular remodeling and function, reduces infarct size, and preserves native LV biaxial mechanical properties.
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Affiliation(s)
- Hanjay Wang
- Department of Cardiothoracic Surgery, Stanford University, Stanford, CA, USA
| | - Andrew Wisneski
- Department of Surgery, University of California San Francisco, San Francisco, CA, USA
| | - Michael J Paulsen
- Department of Cardiothoracic Surgery, Stanford University, Stanford, CA, USA
| | - Annabel Imbrie-Moore
- Department of Cardiothoracic Surgery, Stanford University, Stanford, CA, USA; Department of Mechanical Engineering, Stanford University, Stanford, CA, USA
| | - Zhongjie Wang
- Department of Surgery, University of California San Francisco, San Francisco, CA, USA
| | - Yue Xuan
- Department of Surgery, University of California San Francisco, San Francisco, CA, USA
| | | | - Haley J Lucian
- Department of Cardiothoracic Surgery, Stanford University, Stanford, CA, USA
| | - Anahita Eskandari
- Department of Cardiothoracic Surgery, Stanford University, Stanford, CA, USA
| | - Akshara D Thakore
- Department of Cardiothoracic Surgery, Stanford University, Stanford, CA, USA
| | - Justin M Farry
- Department of Cardiothoracic Surgery, Stanford University, Stanford, CA, USA
| | - Camille E Hironaka
- Department of Cardiothoracic Surgery, Stanford University, Stanford, CA, USA
| | | | - Amanda N Steele
- Department of Cardiothoracic Surgery, Stanford University, Stanford, CA, USA; Department of Bioengineering, Stanford University, Stanford, CA, USA
| | - Lyndsay M Stapleton
- Department of Cardiothoracic Surgery, Stanford University, Stanford, CA, USA; Department of Bioengineering, Stanford University, Stanford, CA, USA
| | - Kiah M Williams
- Department of Cardiothoracic Surgery, Stanford University, Stanford, CA, USA
| | - Matthew A Wu
- Department of Cardiothoracic Surgery, Stanford University, Stanford, CA, USA
| | - John W MacArthur
- Department of Cardiothoracic Surgery, Stanford University, Stanford, CA, USA
| | - Y Joseph Woo
- Department of Cardiothoracic Surgery, Stanford University, Stanford, CA, USA; Department of Bioengineering, Stanford University, Stanford, CA, USA.
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13
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A viscoelastic adhesive epicardial patch for treating myocardial infarction. Nat Biomed Eng 2019; 3:632-643. [PMID: 30988471 DOI: 10.1038/s41551-019-0380-9] [Citation(s) in RCA: 107] [Impact Index Per Article: 21.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Accepted: 03/05/2019] [Indexed: 01/10/2023]
Abstract
Acellular epicardial patches that treat myocardial infarction by increasing the mechanical integrity of damaged left ventricular tissues exhibit widely scattered therapeutic efficacy. Here, we introduce a viscoelastic adhesive patch, made of an ionically crosslinked transparent hydrogel, that accommodates the cyclic deformation of the myocardium and outperforms most existing acellular epicardial patches in reversing left ventricular remodelling and restoring heart function after both acute and subacute myocardial infarction in rats. The superior performance of the patch results from its relatively low dynamic modulus, designed at the so-called 'gel point' via finite-element simulations of left ventricular remodelling so as to balance the fluid and solid properties of the material.
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14
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Holmes JW. Model First and Ask Questions Later: Confessions of a Reformed Experimentalist. J Biomech Eng 2019; 141:2730665. [PMID: 30958518 PMCID: PMC6611345 DOI: 10.1115/1.4043432] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Revised: 03/28/2019] [Indexed: 12/26/2022]
Abstract
This paper is an invited perspective written in association with the awarding of the 2018 American Society of Mechanical Engineers Van C. Mow Medal. Inspired by Professor Mow's collaboration with Professor Michael Lai and the role mathematical modeling played in their work on cartilage biomechanics, this article uses our group's work on myocardial infarct healing as an example of the potential value of models in modern experimental biomechanics. Focusing more on the thought process and lessons learned from our studies on infarct mechanics than on the details of the science, this article argues that the complexity of current research questions and the wealth of information already available about almost any cell, tissue, or organ should change how we approach problems and design experiments. In particular, this paper proposes that constructing a mathematical or computational model is now in many cases a critical prerequisite to designing scientifically useful, informative experiments.
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Affiliation(s)
- Jeffrey W. Holmes
- Departments of Biomedical
Engineering and Medicine,
Robert M. Berne Cardiovascular
Research Center, and Center for
Engineering in Medicine,
University of Virginia,
P.O. Box 800759,
Charlottesville, VA 22908
e-mail:
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15
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Varela CE, Fan Y, Roche ET. Optimizing Epicardial Restraint and Reinforcement Following Myocardial Infarction: Moving Towards Localized, Biomimetic, and Multitherapeutic Options. Biomimetics (Basel) 2019; 4:E7. [PMID: 31105193 PMCID: PMC6477619 DOI: 10.3390/biomimetics4010007] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Revised: 12/31/2018] [Accepted: 01/09/2019] [Indexed: 02/06/2023] Open
Abstract
The mechanical reinforcement of the ventricular wall after a myocardial infarction has been shown to modulate and attenuate negative remodeling that can lead to heart failure. Strategies include wraps, meshes, cardiac patches, or fluid-filled bladders. Here, we review the literature describing these strategies in the two broad categories of global restraint and local reinforcement. We further subdivide the global restraint category into biventricular and univentricular support. We discuss efforts to optimize devices in each of these categories, particularly in the last five years. These include adding functionality, biomimicry, and adjustability. We also discuss computational models of these strategies, and how they can be used to predict the reduction of stresses in the heart muscle wall. We discuss the range of timing of intervention that has been reported. Finally, we give a perspective on how novel fabrication technologies, imaging techniques, and computational models could potentially enhance these therapeutic strategies.
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Affiliation(s)
- Claudia E Varela
- Harvard-MIT Program in Health Sciences and Technology, Cambridge, MA 02139, USA.
- Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
| | - Yiling Fan
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
| | - Ellen T Roche
- Harvard-MIT Program in Health Sciences and Technology, Cambridge, MA 02139, USA.
- Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
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16
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Witzenburg CM, Holmes JW. A Comparison of Phenomenologic Growth Laws for Myocardial Hypertrophy. JOURNAL OF ELASTICITY 2017; 129:257-281. [PMID: 29632418 PMCID: PMC5889094 DOI: 10.1007/s10659-017-9631-8] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
The heart grows in response to changes in hemodynamic loading during normal development and in response to valve disease, hypertension, and other pathologies. In general, a left ventricle subjected to increased afterload (pressure overloading) exhibits concentric growth characterized by thickening of individual myocytes and the heart wall, while one experiencing increased preload (volume overloading) exhibits eccentric growth characterized by lengthening of myocytes and dilation of the cavity. Predictive models of cardiac growth could be important tools in evaluating treatments, guiding clinical decision making, and designing novel therapies for a range of diseases. Thus, in the past 20 years there has been considerable effort to simulate growth within the left ventricle. While a number of published equations or systems of equations (often termed "growth laws") can capture some aspects of experimentally observed growth patterns, no direct comparisons of the various published models have been performed. Here we examine eight of these laws and compare them in a simple test-bed in which we imposed stretches measured during in vivo pressure and volume overload. Laws were compared based on their ability to predict experimentally measured patterns of growth in the myocardial fiber and radial directions as well as the ratio of fiber-to-radial growth. Three of the eight laws were able to reproduce most key aspects of growth following both pressure and volume overload. Although these three growth laws utilized different approaches to predict hypertrophy, they all employed multiple inputs that were weakly correlated during in vivo overload and therefore provided independent information about mechanics.
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Affiliation(s)
- Colleen M. Witzenburg
- Department of Biomedical Engineering, University of Virginia,
Charlottesville, VA, USA
| | - Jeffrey W. Holmes
- Department of Biomedical Engineering, University of Virginia,
Charlottesville, VA, USA
- Department of Medicine, University of Virginia, Charlottesville, VA,
USA
- Robert M. Berne Cardiovascular Research Center, University of
Virginia, Charlottesville, VA, USA
- Phone: 434-924-8797
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17
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Richardson WJ, Holmes JW. Emergence of Collagen Orientation Heterogeneity in Healing Infarcts and an Agent-Based Model. Biophys J 2017; 110:2266-77. [PMID: 27224491 DOI: 10.1016/j.bpj.2016.04.014] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Revised: 12/30/2015] [Accepted: 04/07/2016] [Indexed: 01/01/2023] Open
Abstract
Spatial heterogeneity of matrix structure can be an important determinant of tissue function. Although bulk properties of collagen structure in healing myocardial infarcts have been characterized previously, regional heterogeneity in infarct structure has received minimal attention. Herein, we quantified regional variations of collagen and nuclear orientations over the initial weeks of healing after infarction in rats, and employed a computational model of infarct remodeling to test potential explanations for the heterogeneity we observed in vivo. Fiber and cell orientation maps were generated from infarct samples acquired previously at 1, 2, 3, and 6 weeks postinfarction in a rat ligation model. We analyzed heterogeneity by calculating the dot product of each fiber or cell orientation vector with every other fiber or cell orientation vector, and plotting that dot product versus distance between the fibers or cells. This analysis revealed prominent regional heterogeneity, with alignment of both fibers and cell nuclei in local pockets far exceeding the global average. Using an agent-based model of fibroblast-mediated collagen remodeling, we found that similar levels of heterogeneity can spontaneously emerge from initially isotropic matrix via locally reinforcing cell-matrix interactions. Specifically, cells that sensed fiber orientation at a distance or remodeled fibers at a distance by traction-mediated reorientation or aligned deposition gave rise to regionally heterogeneous structures. However, only the simulations in which cells deposited collagen fibers aligned with their own orientation reproduced experimentally measured patterns of heterogeneity across all time points. These predictions warrant experimental follow-up to test the role of such mechanisms in vivo and identify opportunities to control heterogeneity for therapeutic benefit.
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Affiliation(s)
- William J Richardson
- Department of Biomedical Engineering, University of Virginia, Charlottesville, Virginia; Robert M. Berne Cardiovascular Research Center, University of Virginia, Charlottesville, Virginia
| | - Jeffrey W Holmes
- Department of Biomedical Engineering, University of Virginia, Charlottesville, Virginia; Department of Medicine, University of Virginia, Charlottesville, Virginia; Robert M. Berne Cardiovascular Research Center, University of Virginia, Charlottesville, Virginia.
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18
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D'Amore A, Yoshizumi T, Luketich SK, Wolf MT, Gu X, Cammarata M, Hoff R, Badylak SF, Wagner WR. Bi-layered polyurethane - Extracellular matrix cardiac patch improves ischemic ventricular wall remodeling in a rat model. Biomaterials 2016; 107:1-14. [PMID: 27579776 DOI: 10.1016/j.biomaterials.2016.07.039] [Citation(s) in RCA: 93] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Revised: 07/28/2016] [Accepted: 07/31/2016] [Indexed: 01/28/2023]
Abstract
As an intervention to abrogate ischemic cardiomyopathy, the concept of applying a temporary, local patch to the surface of the recently infarcted ventricle has been explored from a number of design perspectives. Two important features considered for such a cardiac patch include the provision of appropriate mechanical support and the capacity to influence the remodeling pathway by providing cellular or biomolecule delivery. The objective of this report was to focus on these two features by first evaluating the incorporation of a cardiac extracellular matrix (ECM) component, and second by evaluating the impact of patch anisotropy on the pathological remodeling process initiated by myocardial infarction. The functional outcomes of microfibrous, elastomeric, biodegradable cardiac patches have been evaluated in a rat chronic infarction model. Ten weeks after infarction and 8 wk after patch epicardial placement, echocardiographic function, tissue-level structural remodeling (e.g., biaxial mechanical response and microstructural analysis), and cellular level remodeling were assessed. The results showed that the incorporation of a cardiac ECM altered the progression of several keys aspects of maladaptive remodeling following myocardial infarction. This included decreasing LV global mechanical compliance, inhibiting echocardiographically-measured functional deterioration, mitigating scar formation and LV wall thinning, and promoting angiogenesis. In evaluating the impact of patch anisotropy, no effects from the altered patch mechanics were detected after 8 wk, possibly due to patch fibrous encapsulation. Overall, this study demonstrates the benefit of a cardiac patch design that combines both ventricle mechanical support, through a biodegradable, fibrillary elastomeric component, and the incorporation of ECM-based hydrogel components.
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Affiliation(s)
- Antonio D'Amore
- Department of Bioengineering, McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA; Department of Chemical Engineering, McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA; Fondazione RiMED, Italy; DICGIM, Università di Palermo, Italy
| | - Tomo Yoshizumi
- Department of Bioengineering, McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA; Department of Chemical Engineering, McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Samuel K Luketich
- Department of Bioengineering, McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA; Department of Chemical Engineering, McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Matthew T Wolf
- Department of Bioengineering, McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA; Department of Chemical Engineering, McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Xinzhu Gu
- Department of Bioengineering, McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA; Department of Chemical Engineering, McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | | | - Richard Hoff
- Department of Bioengineering, McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA; Department of Chemical Engineering, McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Stephen F Badylak
- Department of Bioengineering, McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA; Department of Chemical Engineering, McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - William R Wagner
- Department of Bioengineering, McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA; Department of Chemical Engineering, McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA; Department of Surgery, McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA.
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19
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Novel therapeutic strategies targeting fibroblasts and fibrosis in heart disease. Nat Rev Drug Discov 2016; 15:620-638. [PMID: 27339799 DOI: 10.1038/nrd.2016.89] [Citation(s) in RCA: 220] [Impact Index Per Article: 27.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Our understanding of the functions of cardiac fibroblasts has moved beyond their roles in heart structure and extracellular matrix generation and now includes their contributions to paracrine, mechanical and electrical signalling during ontogenesis and normal cardiac activity. Fibroblasts also have central roles in pathogenic remodelling during myocardial ischaemia, hypertension and heart failure. As key contributors to scar formation, they are crucial for tissue repair after interventions including surgery and ablation. Novel experimental approaches targeting cardiac fibroblasts are promising potential therapies for heart disease. Indeed, several existing drugs act, at least partially, through effects on cardiac connective tissue. This Review outlines the origins and roles of fibroblasts in cardiac development, homeostasis and disease; illustrates the involvement of fibroblasts in current and emerging clinical interventions; and identifies future targets for research and development.
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20
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Ongstad EL, Gourdie RG. Can heart function lost to disease be regenerated by therapeutic targeting of cardiac scar tissue? Semin Cell Dev Biol 2016; 58:41-54. [PMID: 27234380 DOI: 10.1016/j.semcdb.2016.05.020] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2016] [Revised: 05/18/2016] [Accepted: 05/23/2016] [Indexed: 01/14/2023]
Abstract
Myocardial infarction results in scar tissue that cannot actively contribute to heart mechanical function and frequently causes lethal arrhythmias. The healing response after infarction involves inflammation, biochemical signaling, changes in cellular phenotype, activity, and organization, and alterations in electrical conduction due to variations in cell and tissue geometry and alterations in protein expression, organization, and function - particularly in membrane channels. The intensive research focus on regeneration of myocardial tissues has, as of yet, only met with modest success, with no near-term prospect of improving standard-of-care for patients with heart disease. An alternative concept for novel therapeutic approach is the rejuvenation of cardiac electrical and mechanical properties through the modification of scar tissue. Several peptide therapeutics, locally applied genetic therapies, or delivery of genetically modified cells have shown promise in improving the characteristics of the fibrous scar and post-myocardial infarction prognosis in experimental models. This review highlights several factors that contribute to arrhythmogenesis in scar formation and how these might be targeted to regenerate some of the electrical and mechanical function of the post-MI scar.
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Affiliation(s)
- Emily L Ongstad
- Center for Heart and Regenerative Medicine Research, Virginia Tech Carilion Research Institute, 2 Riverside Circle, Roanoke, VA 24016, USA.
| | - Robert G Gourdie
- Center for Heart and Regenerative Medicine Research, Virginia Tech Carilion Research Institute, 2 Riverside Circle, Roanoke, VA 24016, USA; Virginia Tech-Wake Forest University School of Biomedical Engineering and Sciences, 317 Kelly Hall, Stanger Street, Blacksburg, VA 24061, USA; Department of Emergency Medicine, Carilion Clinic, 1906 Belleview Avenue, Roanoke VA 24014, USA.
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21
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Clarke SA, Richardson WJ, Holmes JW. Modifying the mechanics of healing infarcts: Is better the enemy of good? J Mol Cell Cardiol 2015; 93:115-24. [PMID: 26631496 DOI: 10.1016/j.yjmcc.2015.11.028] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/16/2015] [Revised: 11/09/2015] [Accepted: 11/26/2015] [Indexed: 02/06/2023]
Abstract
Myocardial infarction (MI) is a major source of morbidity and mortality worldwide, with over 7 million people suffering infarctions each year. Heart muscle damaged during MI is replaced by a collagenous scar over a period of several weeks, and the mechanical properties of that scar tissue are a key determinant of serious post-MI complications such as infarct rupture, depression of heart function, and progression to heart failure. Thus, there is increasing interest in developing therapies that modify the structure and mechanics of healing infarct scar. Yet most prior attempts at therapeutic scar modification have failed, some catastrophically. This article reviews available information about the mechanics of healing infarct scar and the functional impact of scar mechanical properties, and attempts to infer principles that can better guide future attempts to modify scar. One important conclusion is that collagen structure, mechanics, and remodeling of healing infarct scar vary so widely among experimental models that any novel therapy should be tested across a range of species, infarct locations, and reperfusion protocols. Another lesson from past work is that the biology and mechanics of healing infarcts are sufficiently complex that the effects of interventions are often counterintuitive; for example, increasing infarct stiffness has little effect on heart function, and inhibition of matrix metalloproteases (MMPs) has little effect on scar collagen content. Computational models can help explain such counterintuitive results, and are becoming an increasingly important tool for integrating known information to better identify promising therapies and design experiments to test them. Moving forward, potentially exciting new opportunities for therapeutic modification of infarct mechanics include modulating anisotropy and promoting scar compaction.
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Affiliation(s)
- Samantha A Clarke
- Department of Biomedical Engineering, University of Virginia, United States
| | - William J Richardson
- Department of Biomedical Engineering, University of Virginia, United States; Robert M. Berne Cardiovascular Research Center, University of Virginia, United States
| | - Jeffrey W Holmes
- Department of Biomedical Engineering, University of Virginia, United States; Department of Medicine, University of Virginia, United States; Robert M. Berne Cardiovascular Research Center, University of Virginia, United States.
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Holmes JW, Laksman Z, Gepstein L. Making better scar: Emerging approaches for modifying mechanical and electrical properties following infarction and ablation. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2015; 120:134-48. [PMID: 26615948 DOI: 10.1016/j.pbiomolbio.2015.11.002] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2015] [Revised: 11/13/2015] [Accepted: 11/20/2015] [Indexed: 12/31/2022]
Abstract
Following myocardial infarction (MI), damaged myocytes are replaced by collagenous scar tissue, which serves an important mechanical function - maintaining integrity of the heart wall against enormous mechanical forces - but also disrupts electrical function as structural and electrical remodeling in the infarct and borderzone predispose to re-entry and ventricular tachycardia. Novel emerging regenerative approaches aim to replace this scar tissue with viable myocytes. Yet an alternative strategy of therapeutically modifying selected scar properties may also prove important, and in some cases may offer similar benefits with lower risk or regulatory complexity. Here, we review potential goals for such modifications as well as recent proof-of-concept studies employing specific modifications, including gene therapy to locally increase conduction velocity or prolong the refractory period in and around the infarct scar, and modification of scar anisotropy to improve regional mechanics and pump function. Another advantage of scar modification techniques is that they have applications well beyond MI. In particular, ablation treats electrical abnormalities of the heart by intentionally generating scar to block aberrant conduction pathways. Yet in diseases such as atrial fibrillation (AF) where ablation can be extensive, treating the electrical disorder can significantly impair mechanical function. Creating smaller, denser scars that more effectively block conduction, and choosing the location of those lesions by balancing their electrical and mechanical impacts, could significantly improve outcomes for AF patients. We review some recent advances in this area, including the use of computational models to predict the mechanical effects of specific lesion sets and gene therapy for functional ablation. Overall, emerging techniques for modifying scar properties represents a potentially important set of tools for improving patient outcomes across a range of heart diseases, whether used in place of or as an adjunct to regenerative approaches.
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Affiliation(s)
- Jeffrey W Holmes
- Departments of Biomedical Engineering and Medicine, Robert M. Berne Cardiovascular Research Center, University of Virginia, Charlottesville, VA, United States.
| | - Zachary Laksman
- Cardiac Electrophysiology, University of British Columbia, Vancouver, BC, Canada
| | - Lior Gepstein
- Departments of Cardiology (Ramban Health Care Campus) and Physiology, The Rappaport Faculty of Medicine and Research Institute, Technion - Israel Institute of Technology, Haifa, Israel
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Richardson WJ, Holmes JW. Why Is Infarct Expansion Such an Elusive Therapeutic Target? J Cardiovasc Transl Res 2015; 8:421-30. [PMID: 26390882 PMCID: PMC4846979 DOI: 10.1007/s12265-015-9652-2] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/12/2015] [Accepted: 08/28/2015] [Indexed: 11/25/2022]
Abstract
Myocardial infarct expansion has been associated with an increased risk of infarct rupture and progression to heart failure, motivating therapies such as infarct restraint and polymer injection that aim to limit infarct expansion. However, an exhaustive review of quantitative studies of infarct remodeling reveals that only half found chronic in-plane expansion, and many reported in-plane compaction. Using a finite element model, we demonstrate that the balance between scar stiffening due to collagen accumulation and increased wall stresses due to infarct thinning can produce either expansion or compaction in the pressurized heart-potentially explaining variability in the literature-and that loaded dimensions are much more sensitive to changes in thickness than in stiffness. Our analysis challenges the concept that in-plane expansion is a central feature of post-infarction remodeling; rather, available data suggest that radial thinning is the dominant process during infarct healing and may be an attractive therapeutic target.
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Affiliation(s)
- William J Richardson
- Department of Biomedical Engineering, University of Virginia, Box 800759, Charlottesville, VA, 22908, USA.
- Robert M. Berne Cardiovascular Research Center, University of Virginia, Charlottesville, VA, USA.
| | - Jeffrey W Holmes
- Department of Biomedical Engineering, University of Virginia, Box 800759, Charlottesville, VA, 22908, USA
- Department of Medicine, University of Virginia, Charlottesville, VA, USA
- Robert M. Berne Cardiovascular Research Center, University of Virginia, Charlottesville, VA, USA
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Abstract
The heart pumps blood to maintain circulation and ensure the delivery of oxygenated blood to all the organs of the body. Mechanics play a critical role in governing and regulating heart function under both normal and pathological conditions. Biological processes and mechanical stress are coupled together in regulating myocyte function and extracellular matrix structure thus controlling heart function. Here, we offer a brief introduction to the biomechanics of left ventricular function and then summarize recent progress in the study of the effects of mechanical stress on ventricular wall remodeling and cardiac function as well as the effects of wall mechanical properties on cardiac function in normal and dysfunctional hearts. Various mechanical models to determine wall stress and cardiac function in normal and diseased hearts with both systolic and diastolic dysfunction are discussed. The results of these studies have enhanced our understanding of the biomechanical mechanism in the development and remodeling of normal and dysfunctional hearts. Biomechanics provide a tool to understand the mechanism of left ventricular remodeling in diastolic and systolic dysfunction and guidance in designing and developing new treatments.
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Affiliation(s)
- Andrew P. Voorhees
- Department of Mechanical Engineering, The University of Texas at San Antonio, Biomedical Engineering Program, UTSA-UTHSCSA
| | - Hai-Chao Han
- Department of Mechanical Engineering, The University of Texas at San Antonio, Biomedical Engineering Program, UTSA-UTHSCSA
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25
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Richardson WJ, Clarke SA, Quinn TA, Holmes JW. Physiological Implications of Myocardial Scar Structure. Compr Physiol 2015; 5:1877-909. [PMID: 26426470 DOI: 10.1002/cphy.c140067] [Citation(s) in RCA: 165] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Once myocardium dies during a heart attack, it is replaced by scar tissue over the course of several weeks. The size, location, composition, structure, and mechanical properties of the healing scar are all critical determinants of the fate of patients who survive the initial infarction. While the central importance of scar structure in determining pump function and remodeling has long been recognized, it has proven remarkably difficult to design therapies that improve heart function or limit remodeling by modifying scar structure. Many exciting new therapies are under development, but predicting their long-term effects requires a detailed understanding of how infarct scar forms, how its properties impact left ventricular function and remodeling, and how changes in scar structure and properties feed back to affect not only heart mechanics but also electrical conduction, reflex hemodynamic compensations, and the ongoing process of scar formation itself. In this article, we outline the scar formation process following a myocardial infarction, discuss interpretation of standard measures of heart function in the setting of a healing infarct, then present implications of infarct scar geometry and structure for both mechanical and electrical function of the heart and summarize experiences to date with therapeutic interventions that aim to modify scar geometry and structure. One important conclusion that emerges from the studies reviewed here is that computational modeling is an essential tool for integrating the wealth of information required to understand this complex system and predict the impact of novel therapies on scar healing, heart function, and remodeling following myocardial infarction.
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Affiliation(s)
- William J Richardson
- Department of Biomedical Engineering, University of Virginia, Charlottesville, Virginia, USA.,Robert M. Berne Cardiovascular Research Center, University of Virginia, Charlottesville, Virginia, USA
| | - Samantha A Clarke
- Department of Biomedical Engineering, University of Virginia, Charlottesville, Virginia, USA
| | - T Alexander Quinn
- Department of Physiology and Biophysics, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Jeffrey W Holmes
- Department of Biomedical Engineering, University of Virginia, Charlottesville, Virginia, USA.,Department of Medicine, University of Virginia, Charlottesville, Virginia, USA.,Robert M. Berne Cardiovascular Research Center, University of Virginia, Charlottesville, Virginia, USA
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26
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Lee LC, Sundnes J, Genet M, Wenk JF, Wall ST. An integrated electromechanical-growth heart model for simulating cardiac therapies. Biomech Model Mechanobiol 2015; 15:791-803. [PMID: 26376641 DOI: 10.1007/s10237-015-0723-8] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2015] [Accepted: 08/25/2015] [Indexed: 01/27/2023]
Abstract
An emerging class of models has been developed in recent years to predict cardiac growth and remodeling (G&R). We recently developed a cardiac G&R constitutive model that predicts remodeling in response to elevated hemodynamics loading, and a subsequent reversal of the remodeling process when the loading is reduced. Here, we describe the integration of this G&R model to an existing strongly coupled electromechanical model of the heart. A separation of timescale between growth deformation and elastic deformation was invoked in this integrated electromechanical-growth heart model. To test our model, we applied the G&R scheme to simulate the effects of myocardial infarction in a realistic left ventricular (LV) geometry using the finite element method. We also simulate the effects of a novel therapy that is based on alteration of the infarct mechanical properties. We show that our proposed model is able to predict key features that are consistent with experiments. Specifically, we show that the presence of a non-contractile infarct leads to a dilation of the left ventricle that results in a rightward shift of the pressure volume loop. Our model also predicts that G&R is attenuated by a reduction in LV dilation when the infarct stiffness is increased.
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Affiliation(s)
- Lik Chuan Lee
- Department of Mechanical Engineering, Michigan State University, East Lansing, MI, USA.
| | | | - Martin Genet
- Institute of Biomedical Engineering, ETH Zurich, Zurich, Switzerland
| | - Jonathan F Wenk
- Department of Mechanical Engineering, University of Kentucky, Lexington, KY, USA
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Voorhees AP, DeLeon-Pennell KY, Ma Y, Halade GV, Yabluchanskiy A, Iyer RP, Flynn E, Cates CA, Lindsey ML, Han HC. Building a better infarct: Modulation of collagen cross-linking to increase infarct stiffness and reduce left ventricular dilation post-myocardial infarction. J Mol Cell Cardiol 2015; 85:229-39. [PMID: 26080361 PMCID: PMC4530076 DOI: 10.1016/j.yjmcc.2015.06.006] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/07/2015] [Revised: 06/08/2015] [Accepted: 06/09/2015] [Indexed: 11/29/2022]
Abstract
Matrix metalloproteinase-9 (MMP-9) deletion attenuates collagen accumulation and dilation of the left ventricle (LV) post-myocardial infarction (MI); however the biomechanical mechanisms underlying the improved outcome are poorly understood. The aim of this study was to determine the mechanisms whereby MMP-9 deletion alters collagen network composition and assembly in the LV post-MI to modulate the mechanical properties of myocardial scar tissue. Adult C57BL/6J wild-type (WT; n=88) and MMP-9 null (MMP-9(-/-); n=92) mice of both sexes underwent permanent coronary artery ligation and were compared to day 0 controls (n=42). At day 7 post-MI, WT LVs displayed a 3-fold increase in end-diastolic volume, while MMP-9(-/-) showed only a 2-fold increase (p<0.05). Biaxial mechanical testing revealed that MMP-9(-/-) infarcts were stiffer than WT infarcts, as indicated by a 1.3-fold reduction in predicted in vivo circumferential stretch (p<0.05). Paradoxically, MMP-9(-/-) infarcts had a 1.8-fold reduction in collagen deposition (p<0.05). This apparent contradiction was explained by a 3.1-fold increase in lysyl oxidase (p<0.05) in MMP-9(-/-) infarcts, indicating that MMP-9 deletion increased collagen cross-linking activity. Furthermore, MMP-9 deletion led to a 3.0-fold increase in bone morphogenetic protein-1, the metalloproteinase that cleaves pro-collagen and pro-lysyl oxidase (p<0.05) and reduced fibronectin fragmentation by 49% (p<0.05) to enhance lysyl oxidase activity. We conclude that MMP-9 deletion increases infarct stiffness and prevents LV dilation by reducing collagen degradation and facilitating collagen assembly and cross-linking through preservation of the fibronectin network and activation of lysyl oxidase.
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Affiliation(s)
- Andrew P Voorhees
- Department of Mechanical Engineering, The University of Texas at San Antonio, USA; Joint Biomedical Engineering Program, UTSA-UTHSCSA, USA; San Antonio Cardiovascular Proteomics Center, USA
| | - Kristine Y DeLeon-Pennell
- San Antonio Cardiovascular Proteomics Center, USA; Mississippi Center for Heart Research, Department of Physiology and Biophysics, University of Mississippi Medical Center, USA
| | - Yonggang Ma
- San Antonio Cardiovascular Proteomics Center, USA; Mississippi Center for Heart Research, Department of Physiology and Biophysics, University of Mississippi Medical Center, USA
| | - Ganesh V Halade
- San Antonio Cardiovascular Proteomics Center, USA; Division of Cardiovascular Disease, Department of Medicine, The University of Alabama at Birmingham, USA
| | - Andriy Yabluchanskiy
- San Antonio Cardiovascular Proteomics Center, USA; Mississippi Center for Heart Research, Department of Physiology and Biophysics, University of Mississippi Medical Center, USA; Research Service, G.V. (Sonny) Montgomery Veterans Affairs Medical Center, USA
| | - Rugmani Padmanabhan Iyer
- San Antonio Cardiovascular Proteomics Center, USA; Mississippi Center for Heart Research, Department of Physiology and Biophysics, University of Mississippi Medical Center, USA
| | - Elizabeth Flynn
- Mississippi Center for Heart Research, Department of Physiology and Biophysics, University of Mississippi Medical Center, USA
| | - Courtney A Cates
- Mississippi Center for Heart Research, Department of Physiology and Biophysics, University of Mississippi Medical Center, USA
| | - Merry L Lindsey
- Joint Biomedical Engineering Program, UTSA-UTHSCSA, USA; San Antonio Cardiovascular Proteomics Center, USA; Mississippi Center for Heart Research, Department of Physiology and Biophysics, University of Mississippi Medical Center, USA; Research Service, G.V. (Sonny) Montgomery Veterans Affairs Medical Center, USA
| | - Hai-Chao Han
- Department of Mechanical Engineering, The University of Texas at San Antonio, USA; Joint Biomedical Engineering Program, UTSA-UTHSCSA, USA; San Antonio Cardiovascular Proteomics Center, USA.
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28
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Zhang B, Montgomery M, Davenport-Huyer L, Korolj A, Radisic M. Platform technology for scalable assembly of instantaneously functional mosaic tissues. SCIENCE ADVANCES 2015; 1:e1500423. [PMID: 26601234 PMCID: PMC4643798 DOI: 10.1126/sciadv.1500423] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2015] [Accepted: 07/13/2015] [Indexed: 05/05/2023]
Abstract
Engineering mature tissues requires a guided assembly of cells into organized three-dimensional (3D) structures with multiple cell types. Guidance is usually achieved by microtopographical scaffold cues or by cell-gel compaction. The assembly of individual units into functional 3D tissues is often time-consuming, relying on cell ingrowth and matrix remodeling, whereas disassembly requires an invasive method that includes either matrix dissolution or mechanical cutting. We invented Tissue-Velcro, a bio-scaffold with a microfabricated hook and loop system. The assembly of Tissue-Velcro preserved the guided cell alignment realized by the topographical features in the 2D scaffold mesh and allowed for the instant establishment of coculture conditions by spatially defined stacking of cardiac cell layers or through endothelial cell coating. The assembled cardiac 3D tissue constructs were immediately functional as measured by their ability to contract in response to electrical field stimulation. Facile, on-demand tissue disassembly was demonstrated while preserving the structure, physical integrity, and beating function of individual layers.
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Affiliation(s)
- Boyang Zhang
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario M5S 3E5, Canada
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario M5S 3G9, Canada
| | - Miles Montgomery
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario M5S 3E5, Canada
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario M5S 3G9, Canada
| | - Locke Davenport-Huyer
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario M5S 3E5, Canada
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario M5S 3G9, Canada
| | - Anastasia Korolj
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario M5S 3E5, Canada
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario M5S 3G9, Canada
| | - Milica Radisic
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario M5S 3E5, Canada
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario M5S 3G9, Canada
- Corresponding author. E-mail:
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29
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Clarke SA, Goodman NC, Ailawadi G, Holmes JW. Effect of Scar Compaction on the Therapeutic Efficacy of Anisotropic Reinforcement Following Myocardial Infarction in the Dog. J Cardiovasc Transl Res 2015; 8:353-61. [PMID: 26077797 DOI: 10.1007/s12265-015-9637-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/22/2015] [Accepted: 05/27/2015] [Indexed: 04/21/2023]
Abstract
Cardiac restraint devices have been used following myocardial infarction (MI) to limit left ventricular (LV) dilation, although isotropic restraints have not been shown to improve post-MI LV function. We have previously shown that anisotropic reinforcement of acute infarcts dramatically improves LV function. This study examined the effects of chronic, anisotropic infarct restraint on LV function and remodeling. Hemodynamics, infarct scar structure, and LV volumes were measured in 28 infarcted dogs (14 reinforced, 14 control). Longitudinal restraint reduced 48-h LV volumes, but no differences in LV volume, function, or infarct scar structure were observed after 8 weeks of healing. All scars underwent substantial compaction during healing; we hypothesize that compaction negated the effects of restraint therapy by mechanically unloading the restraint device. Our results lend support to the concept of adjustable restraint devices and suggest that scar compaction may explain some of the variability in published studies of local infarct restraint.
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Affiliation(s)
- Samantha A Clarke
- Department of Biomedical Engineering, University of Virginia, Charlottesville, VA, USA
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30
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Huyer LD, Montgomery M, Zhao Y, Xiao Y, Conant G, Korolj A, Radisic M. Biomaterial based cardiac tissue engineering and its applications. Biomed Mater 2015; 10:034004. [PMID: 25989939 PMCID: PMC4464787 DOI: 10.1088/1748-6041/10/3/034004] [Citation(s) in RCA: 69] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Cardiovascular disease is a leading cause of death worldwide, necessitating the development of effective treatment strategies. A myocardial infarction involves the blockage of a coronary artery leading to depletion of nutrient and oxygen supply to cardiomyocytes and massive cell death in a region of the myocardium. Cardiac tissue engineering is the growth of functional cardiac tissue in vitro on biomaterial scaffolds for regenerative medicine application. This strategy relies on the optimization of the complex relationship between cell networks and biomaterial properties. In this review, we discuss important biomaterial properties for cardiac tissue engineering applications, such as elasticity, degradation, and induced host response, and their relationship to engineered cardiac cell environments. With these properties in mind, we also emphasize in vitro use of cardiac tissues for high-throughput drug screening and disease modelling.
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Affiliation(s)
- Locke Davenport Huyer
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, ON, Canada
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, ON, Canada
| | - Miles Montgomery
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, ON, Canada
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, ON, Canada
| | - Yimu Zhao
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, ON, Canada
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, ON, Canada
| | - Yun Xiao
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, ON, Canada
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, ON, Canada
| | - Genevieve Conant
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, ON, Canada
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, ON, Canada
| | - Anastasia Korolj
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, ON, Canada
| | - Milica Radisic
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, ON, Canada
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, ON, Canada
- Toronto General Research Institute, University Health Network and IBBME, University of Toronto, Toronto, ON, Canada
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31
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Ye X, Lu L, Kolewe ME, Hearon K, Fischer KM, Coppeta J, Freed LE. Scalable units for building cardiac tissue. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2014; 26:7202-8. [PMID: 25238047 PMCID: PMC4245075 DOI: 10.1002/adma.201403074] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2014] [Revised: 08/14/2014] [Indexed: 05/20/2023]
Abstract
Scalable units for building cardiac tissue are fabricated from biodegradable elastomeric polymers by pairwise stacking of heart-cell scaffolds with sinusoidal internal pore architectures and dedicated perfusable microvessels with rapidly degrading porous interfaces in a parallel flow configuration. This platform supports viable heart cells in vitro and, if validated in vivo, may aid in the regenerative repair of vascularized tissues.
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Affiliation(s)
- Xiaofeng Ye
- Harvard-MIT Division of Health Sciences and Technology, David H. Koch Institute for Integrative Cancer Research, Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Liang Lu
- Harvard-MIT Division of Health Sciences and Technology, David H. Koch Institute for Integrative Cancer Research, Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Martin E. Kolewe
- Harvard-MIT Division of Health Sciences and Technology, David H. Koch Institute for Integrative Cancer Research, Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Keith Hearon
- Harvard-MIT Division of Health Sciences and Technology, David H. Koch Institute for Integrative Cancer Research, Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Kristin M. Fischer
- Harvard-MIT Division of Health Sciences and Technology, David H. Koch Institute for Integrative Cancer Research, Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Jonathan Coppeta
- Biomedical Microsystems Development and Microfabrication Design Groups, Charles Stark Draper Laboratory, Cambridge, MA 02139, USA
| | - Lisa E. Freed
- Harvard-MIT Division of Health Sciences and Technology, David H. Koch Institute for Integrative Cancer Research, Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA 02139, USA. Biomedical Microsystems Development and Microfabrication Design Groups, Charles Stark Draper Laboratory, Cambridge, MA 02139, USA
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32
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Rouillard AD, Holmes JW. Coupled agent-based and finite-element models for predicting scar structure following myocardial infarction. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2014; 115:235-43. [PMID: 25009995 DOI: 10.1016/j.pbiomolbio.2014.06.010] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2014] [Accepted: 06/28/2014] [Indexed: 01/19/2023]
Abstract
Following myocardial infarction, damaged muscle is gradually replaced by collagenous scar tissue. The structural and mechanical properties of the scar are critical determinants of heart function, as well as the risk of serious post-infarction complications such as infarct rupture, infarct expansion, and progression to dilated heart failure. A number of therapeutic approaches currently under development aim to alter infarct mechanics in order to reduce complications, such as implantation of mechanical restraint devices, polymer injection, and peri-infarct pacing. Because mechanical stimuli regulate scar remodeling, the long-term consequences of therapies that alter infarct mechanics must be carefully considered. Computational models have the potential to greatly improve our ability to understand and predict how such therapies alter heart structure, mechanics, and function over time. Toward this end, we developed a straightforward method for coupling an agent-based model of scar formation to a finite-element model of tissue mechanics, creating a multi-scale model that captures the dynamic interplay between mechanical loading, scar deformation, and scar material properties. The agent-based component of the coupled model predicts how fibroblasts integrate local chemical, structural, and mechanical cues as they deposit and remodel collagen, while the finite-element component predicts local mechanics at any time point given the current collagen fiber structure and applied loads. We used the coupled model to explore the balance between increasing stiffness due to collagen deposition and increasing wall stress due to infarct thinning and left ventricular dilation during the normal time course of healing in myocardial infarcts, as well as the negative feedback between strain anisotropy and the structural anisotropy it promotes in healing scar. The coupled model reproduced the observed evolution of both collagen fiber structure and regional deformation following coronary ligation in the rat, and suggests that fibroblast alignment in the direction of greatest stretch provides negative feedback on the level of anisotropy in a scar forming under load. In the future, this coupled model may prove useful in computational design and screening of novel therapies to influence scar formation in mechanically loaded tissues.
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Affiliation(s)
- Andrew D Rouillard
- Department of Biomedical Engineering, University of Virginia, Charlottesville, VA 22908, USA
| | - Jeffrey W Holmes
- Department of Biomedical Engineering, Department of Medicine, Robert M. Berne Cardiovascular Research Center, University of Virginia, Charlottesville, VA 22908, USA.
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33
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Parker KM, Clark AP, Goodman NC, Glover DK, Holmes JW. Comparison of quantitative wall-motion analysis and strain for detection of coronary stenosis with three-dimensional dobutamine stress echocardiography. Echocardiography 2014; 32:349-60. [PMID: 24815588 DOI: 10.1111/echo.12636] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
BACKGROUND Quantitative analysis of wall motion from three-dimensional (3D) dobutamine stress echocardiography (DSE) could provide additional diagnostic information not available from qualitative analysis. In this study, we compare the effectiveness of 3D fractional shortening (3DFS), a measure of wall motion computed from 3D echocardiography (3DE), to strain and strain rate measured with sonomicrometry for detecting critical stenoses during DSE. METHODS Eleven open-chest dogs underwent DSE both with and without a critical stenosis. 3DFS was measured from 3DE images acquired at peak stress. 3DFS was normalized by subtracting average 3DFS during control peak stress (∆3DFS). Strains in the perfusion defect (PD) were measured from sonomicrometry, and PD size and location were measured with microspheres. RESULTS A ∆3DFS abnormality indicated the presence of a critical stenosis with high sensitivity and specificity (88% and 100%, respectively), and ∆3DFS abnormality size correlated with PD size (R(2) = 0.54). The sensitivity and specificity for ∆3DFS were similar to that for area strain (88%, 100%) and circumferential strain and strain rate (88%, 92% and 88%, 86%, respectively), while longitudinal strain and strain rate were less specific. ∆3DFS correlated significantly with both coronary flow reserve (R(2) = 0.71) and PD size (R(2) = 0.97), while area strain correlated with PD size only (R(2) = 0.67), and other measures were not significantly correlated with flow reserve or PD size. CONCLUSION Quantitative wall-motion analysis using ∆3DFS is effective for detecting critical stenoses during DSE, performing similar to 3D strain, and provides potentially useful information on the size and location of a perfusion defect.
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Affiliation(s)
- Katherine M Parker
- Department of Biomedical Engineering, University of Virginia, Charlottesville, Virginia
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34
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Voorhees AP, Han HC. A model to determine the effect of collagen fiber alignment on heart function post myocardial infarction. Theor Biol Med Model 2014; 11:6. [PMID: 24456675 PMCID: PMC3914851 DOI: 10.1186/1742-4682-11-6] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2013] [Accepted: 01/08/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Adverse remodeling of the left ventricle (LV) following myocardial infarction (MI) leads to heart failure. Recent studies have shown that scar anisotropy is a determinant of cardiac function post-MI, however it remains unclear how changes in extracellular matrix (ECM) organization and structure contribute to changes in LV function. The objective of this study is to develop a model to identify potential mechanisms by which collagen structure and organization affect LV function post-MI. METHODS A four-region, multi-scale, cylindrical model of the post-MI LV was developed. The mechanical properties of the infarct region are governed by a constitutive equation based on the uncrimping of collagen fibers. The parameters of this constitutive equation include collagen orientation, angular dispersion, fiber stiffness, crimp angle, and density. Parametric variation of these parameters was used to elucidate the relationship between collagen properties and LV function. RESULTS The mathematical model of the LV revealed several factors that influenced cardiac function post-MI. LV function was maximized when collagen fibers were aligned longitudinally. Increased collagen density was also found to improve stroke volume for longitudinal alignments while increased fiber stiffness decreased stroke volume for circumferential alignments. CONCLUSIONS The results suggest that cardiac function post-MI is best preserved through increased circumferential compliance. Further, this study identifies several collagen fiber-level mechanisms that could potentially regulate both infarct level and organ level mechanics. Improved understanding of the multi-scale relationships between the ECM and LV function will be beneficial in the design of new diagnostic and therapeutic technologies.
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Affiliation(s)
- Andrew P Voorhees
- Biomedical Engineering Program, UTSA-UTHSCSA 1 UTSA Circle, San Antonio, TX 78249, USA
| | - Hai-Chao Han
- Biomedical Engineering Program, UTSA-UTHSCSA 1 UTSA Circle, San Antonio, TX 78249, USA
- Department of Mechanical Engineering, The University of Texas at San Antonio Biomedical Engineering Program, UTSA-UTHSCSA, 1 UTSA Circle, San Antonio, TX 78249, USA
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Kolewe ME, Park H, Gray C, Ye X, Langer R, Freed LE. 3D structural patterns in scalable, elastomeric scaffolds guide engineered tissue architecture. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2013; 25:4459-65. [PMID: 23765688 PMCID: PMC3954574 DOI: 10.1002/adma.201301016] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2013] [Revised: 04/24/2013] [Indexed: 05/22/2023]
Abstract
Microfabricated elastomeric scaffolds with 3D structural patterns are created by semiautomated layer-by-layer assembly of planar polymer sheets with through-pores. The mesoscale interconnected pore architectures governed by the relative alignment of layers are shown to direct cell and muscle-like fiber orientation in both skeletal and cardiac muscle, enabling scale up of tissue constructs towards clinically relevant dimensions.
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Affiliation(s)
- Martin E. Kolewe
- Harvard-MIT Division of Health Sciences and Technology, David H. Koch Institute for Integrative Cancer Research, Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Hyoungshin Park
- Microsystems Development and Microfabrication Process Engineering Groups, Charles Stark Draper Laboratory, Cambridge, MA 02139, USA
| | - Caprice Gray
- Microsystems Development and Microfabrication Process Engineering Groups, Charles Stark Draper Laboratory, Cambridge, MA 02139, USA
| | - Xiaofeng Ye
- Harvard-MIT Division of Health Sciences and Technology, David H. Koch Institute for Integrative Cancer Research, Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Robert Langer
- Harvard-MIT Division of Health Sciences and Technology, David H. Koch Institute for Integrative Cancer Research, Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Lisa E. Freed
- Harvard-MIT Division of Health Sciences and Technology, David H. Koch Institute for Integrative Cancer Research, Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Microsystems Development and Microfabrication Process Engineering Groups, Charles Stark Draper Laboratory, Cambridge, MA 02139, USA
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36
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Cardiac Restraint and Support Following Myocardial Infarction. CARDIOVASCULAR AND CARDIAC THERAPEUTIC DEVICES 2013. [DOI: 10.1007/8415_2013_163] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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37
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Neal RA, Jean A, Park H, Wu PB, Hsiao J, Engelmayr GC, Langer R, Freed LE. Three-dimensional elastomeric scaffolds designed with cardiac-mimetic structural and mechanical features. Tissue Eng Part A 2012. [PMID: 23190320 DOI: 10.1089/ten.tea.2012.0330] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Tissue-engineered constructs, at the interface of material science, biology, engineering, and medicine, have the capacity to improve outcomes for cardiac patients by providing living cells and degradable biomaterials that can regenerate the native myocardium. With an ultimate goal of both delivering cells and providing mechanical support to the healing heart, we designed three-dimensional (3D) elastomeric scaffolds with (1) stiffnesses and anisotropy mimicking explanted myocardial specimens as predicted by finite-element (FE) modeling, (2) systematically varied combinations of rectangular pore pattern, pore aspect ratio, and strut width, and (3) structural features approaching tissue scale. Based on predicted mechanical properties, three scaffold designs were selected from eight candidates for fabrication from poly(glycerol sebacate) by micromolding from silicon wafers. Large 20×20 mm scaffolds with high aspect ratio features (5:1 strut height:strut width) were reproducibly cast, cured, and demolded at a relatively high throughput. Empirically measured mechanical properties demonstrated that scaffolds were cardiac mimetic and validated FE model predictions. Two-layered scaffolds providing fully interconnected pore networks were fabricated by layer-by-layer assembly. C2C12 myoblasts cultured on one-layered scaffolds exhibited specific patterns of cell elongation and interconnectivity that appeared to be guided by the scaffold pore pattern. Neonatal rat heart cells cultured on two-layered scaffolds for 1 week were contractile, both spontaneously and in response to electrical stimulation, and expressed sarcomeric α-actinin, a cardiac biomarker. This work not only demonstrated several scaffold designs that promoted functional assembly of rat heart cells, but also provided the foundation for further computational and empirical investigations of 3D elastomeric scaffolds for cardiac tissue engineering.
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Affiliation(s)
- Rebekah A Neal
- Harvard-MIT Division of Health Sciences and Technology, David H. Koch Institute for Integrative Cancer Research, and Institute for Medical Engineering and Science, Massachusetts Institute of Technology , Cambridge, Massachusetts, USA
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