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Lu RXZ, Rafatian N, Zhao Y, Wagner KT, Beroncal EL, Li B, Lee C, Chen J, Churcher E, Vosoughi D, Liu C, Wang Y, Baker A, Trahtemberg U, Li B, Pierro A, Andreazza AC, dos Santos CC, Radisic M. Cardiac tissue model of immune-induced dysfunction reveals the role of free mitochondrial DNA and the therapeutic effects of exosomes. Sci Adv 2024; 10:eadk0164. [PMID: 38536913 PMCID: PMC10971762 DOI: 10.1126/sciadv.adk0164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Accepted: 02/22/2024] [Indexed: 04/04/2024]
Abstract
Despite tremendous progress in the development of mature heart-on-a-chip models, human cell-based models of myocardial inflammation are lacking. Here, we bioengineered a vascularized heart-on-a-chip with circulating immune cells to model severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-induced acute myocarditis. We observed hallmarks of coronavirus disease (COVID-19)-induced myocardial inflammation, as the presence of immune cells augmented the secretion of proinflammatory cytokines, triggered progressive impairment of contractile function, and altered intracellular calcium transients. An elevation of circulating cell-free mitochondrial DNA (ccf-mtDNA) was measured first in the heart-on-a-chip and then validated in COVID-19 patients with low left ventricular ejection fraction, demonstrating that mitochondrial damage is an important pathophysiological hallmark of inflammation-induced cardiac dysfunction. Leveraging this platform in the context of SARS-CoV-2-induced myocardial inflammation, we established that administration of endothelial cell-derived exosomes effectively rescued the contractile deficit, normalized calcium handling, elevated the contraction force, and reduced the ccf-mtDNA and cytokine release via Toll-like receptor-nuclear factor κB signaling axis.
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Affiliation(s)
- Rick Xing Ze Lu
- Institute of Biomedical Engineering, University of Toronto, Toronto, ON M5S 3G9, Canada
- Mitochondrial Innovation Initiative, MITO2i, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Naimeh Rafatian
- Institute of Biomedical Engineering, University of Toronto, Toronto, ON M5S 3G9, Canada
| | - Yimu Zhao
- Institute of Biomedical Engineering, University of Toronto, Toronto, ON M5S 3G9, Canada
- Toronto General Hospital Research Institute, University Health Network, Toronto, ON M5G 2C4, Canada
| | - Karl T. Wagner
- Institute of Biomedical Engineering, University of Toronto, Toronto, ON M5S 3G9, Canada
| | - Erika L. Beroncal
- Mitochondrial Innovation Initiative, MITO2i, University of Toronto, Toronto, ON M5S 1A8, Canada
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Bo Li
- Hospital for Sick Children, Toronto, ON M5G 1X8, Canada
| | - Carol Lee
- Hospital for Sick Children, Toronto, ON M5G 1X8, Canada
| | - Jingan Chen
- Institute of Biomedical Engineering, University of Toronto, Toronto, ON M5S 3G9, Canada
| | - Eryn Churcher
- Interdepartmental Division of Critical Care, Keenan Research Centre for Biomedical Science, St. Michael’s Hospital, Unity Health Toronto, Toronto, ON M5B 1W8, Canada
| | - Daniel Vosoughi
- Latner Thoracic Laboratories, Toronto General Hospital Research Institute, University Health Network, Toronto, ON M5G 2C4, Canada
- Institute of Medical Science, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Chuan Liu
- Institute of Biomedical Engineering, University of Toronto, Toronto, ON M5S 3G9, Canada
| | - Ying Wang
- Institute of Biomedical Engineering, University of Toronto, Toronto, ON M5S 3G9, Canada
- Toronto General Hospital Research Institute, University Health Network, Toronto, ON M5G 2C4, Canada
| | - Andrew Baker
- Interdepartmental Division of Critical Care, Keenan Research Centre for Biomedical Science, St. Michael’s Hospital, Unity Health Toronto, Toronto, ON M5B 1W8, Canada
| | - Uriel Trahtemberg
- Interdepartmental Division of Critical Care, Keenan Research Centre for Biomedical Science, St. Michael’s Hospital, Unity Health Toronto, Toronto, ON M5B 1W8, Canada
- Galilee Medical Center, Nahariya, Israel
| | - Bowen Li
- Institute of Biomedical Engineering, University of Toronto, Toronto, ON M5S 3G9, Canada
- Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, ON M5S 3M2, Canada
| | - Agostino Pierro
- Hospital for Sick Children, Toronto, ON M5G 1X8, Canada
- Department of Surgery, University of Toronto, Toronto, ON M5T 1P5, Canada
| | - Ana C. Andreazza
- Mitochondrial Innovation Initiative, MITO2i, University of Toronto, Toronto, ON M5S 1A8, Canada
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON M5S 1A8, Canada
- Department of Psychiatry, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Claudia C. dos Santos
- Interdepartmental Division of Critical Care, Keenan Research Centre for Biomedical Science, St. Michael’s Hospital, Unity Health Toronto, Toronto, ON M5B 1W8, Canada
| | - Milica Radisic
- Institute of Biomedical Engineering, University of Toronto, Toronto, ON M5S 3G9, Canada
- Mitochondrial Innovation Initiative, MITO2i, University of Toronto, Toronto, ON M5S 1A8, Canada
- Toronto General Hospital Research Institute, University Health Network, Toronto, ON M5G 2C4, Canada
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, ON M5S 3D5, Canada
- Terrence Donnelly Centre for Cellular & Biomolecular Research, University of Toronto, Toronto, ON, M5S 3E1
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Bannerman D, Pascual-Gil S, Campbell S, Jiang R, Wu Q, Okhovatian S, Wagner KT, Montgomery M, Laflamme MA, Davenport Huyer L, Radisic M. Itaconate and citrate releasing polymer attenuates foreign body response in biofabricated cardiac patches. Mater Today Bio 2024; 24:100917. [PMID: 38234461 PMCID: PMC10792972 DOI: 10.1016/j.mtbio.2023.100917] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2023] [Revised: 12/08/2023] [Accepted: 12/13/2023] [Indexed: 01/19/2024] Open
Abstract
Application of cardiac patches to the heart surface can be undertaken to provide support and facilitate regeneration of the damaged cardiac tissue following ischemic injury. Biomaterial composition is an important consideration in the design of cardiac patch materials as it governs host response to ultimately prevent the undesirable fibrotic response. Here, we investigate a novel patch material, poly (itaconate-co-citrate-co-octanediol) (PICO), in the context of cardiac implantation. Citric acid (CA) and itaconic acid (ITA), the molecular components of PICO, provided a level of protection for cardiac cells during ischemic reperfusion injury in vitro. Biofabricated PICO patches were shown to degrade in accelerated and hydrolytic conditions, with CA and ITA being released upon degradation. Furthermore, the host response to PICO patches after implantation on rat epicardium in vivo was explored and compared to two biocompatible cardiac patch materials, poly (octamethylene (anhydride) citrate) (POMaC) and poly (ethylene glycol) diacrylate (PEGDA). PICO patches resulted in less macrophage infiltration and lower foreign body giant cell reaction compared to the other materials, with corresponding reduction in smooth muscle actin-positive vessel infiltration into the implant region. Overall, this work demonstrates that PICO patches release CA and ITA upon degradation, both of which demonstrate cardioprotective effects on cardiac cells after ischemic injury, and that PICO patches generate a reduced inflammatory response upon implantation to the heart compared to other materials, signifying promise for use in cardiac patch applications.
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Affiliation(s)
- Dawn Bannerman
- Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, ON, Canada
- Institute of Biomedical Engineering, University of Toronto, Toronto, ON, Canada
- Toronto General Health Research Institute, University Health Network, Toronto, ON, Canada
| | - Simon Pascual-Gil
- Institute of Biomedical Engineering, University of Toronto, Toronto, ON, Canada
- Toronto General Health Research Institute, University Health Network, Toronto, ON, Canada
| | - Scott Campbell
- Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, ON, Canada
- Toronto General Health Research Institute, University Health Network, Toronto, ON, Canada
| | - Richard Jiang
- Institute of Biomedical Engineering, University of Toronto, Toronto, ON, Canada
- Toronto General Health Research Institute, University Health Network, Toronto, ON, Canada
| | - Qinghua Wu
- Institute of Biomedical Engineering, University of Toronto, Toronto, ON, Canada
- Toronto General Health Research Institute, University Health Network, Toronto, ON, Canada
| | - Sargol Okhovatian
- Institute of Biomedical Engineering, University of Toronto, Toronto, ON, Canada
- Toronto General Health Research Institute, University Health Network, Toronto, ON, Canada
| | - Karl T. Wagner
- Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, ON, Canada
- Toronto General Health Research Institute, University Health Network, Toronto, ON, Canada
| | - Miles Montgomery
- Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, ON, Canada
- Institute of Biomedical Engineering, University of Toronto, Toronto, ON, Canada
- Toronto General Health Research Institute, University Health Network, Toronto, ON, Canada
| | - Michael A. Laflamme
- McEwen Stem Cell Institute, University Health Network, Toronto, ON, Canada
- Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada
| | - Locke Davenport Huyer
- Applied Oral Sciences, Dalhousie University, Halifax, NS, Canada
- School of Biomedical Engineering, Dalhousie University, Halifax, NS, Canada
- Department of Microbiology & Immunology, Dalhousie University, Halifax, NS, Canada
- Nova Scotia Health, Halifax, NS, Canada
| | - Milica Radisic
- Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, ON, Canada
- Institute of Biomedical Engineering, University of Toronto, Toronto, ON, Canada
- Toronto General Health Research Institute, University Health Network, Toronto, ON, Canada
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3
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Lu RXZ, Rafatian N, Zhao Y, Wagner KT, Beroncal EL, Li B, Lee C, Chen J, Churcher E, Vosoughi D, Wang Y, Baker A, Trahtemberg U, Li B, Pierro A, Andreazza AC, Dos Santos CC, Radisic M. Heart-on-a-chip model of immune-induced cardiac dysfunction reveals the role of free mitochondrial DNA and therapeutic effects of endothelial exosomes. bioRxiv 2023:2023.08.09.552495. [PMID: 37609237 PMCID: PMC10441383 DOI: 10.1101/2023.08.09.552495] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/24/2023]
Abstract
Cardiovascular disease continues to take more human lives than all cancer combined, prompting the need for improved research models and treatment options. Despite a significant progress in development of mature heart-on-a-chip models of fibrosis and cardiomyopathies starting from induced pluripotent stem cells (iPSCs), human cell-based models of myocardial inflammation are lacking. Here, we bioengineered a vascularized heart-on-a-chip system with circulating immune cells to model SARS-CoV-2-induced acute myocarditis. Briefly, we observed hallmarks of COVID-19-induced myocardial inflammation in the heart-on-a-chip model, as the presence of immune cells augmented the expression levels of proinflammatory cytokines, triggered progressive impairment of contractile function and altered intracellular calcium transient activities. An elevation of circulating cell-free mitochondrial DNA (ccf-mtDNA) was measured first in the in vitro heart-on-a-chip model and then validated in COVID-19 patients with low left ventricular ejection fraction (LVEF), demonstrating that mitochondrial damage is an important pathophysiological hallmark of inflammation induced cardiac dysfunction. Leveraging this platform in the context of SARS-CoV-2 induced myocardial inflammation, we established that administration of human umbilical vein-derived EVs effectively rescued the contractile deficit, normalized intracellular calcium handling, elevated the contraction force and reduced the ccf- mtDNA and chemokine release via TLR-NF-kB signaling axis.
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Vizely K, Wagner KT, Mandla S, Gustafson D, Fish JE, Radisic M. Angiopoietin-1 derived peptide hydrogel promotes molecular hallmarks of regeneration and wound healing in dermal fibroblasts. iScience 2023; 26:105984. [PMID: 36818306 PMCID: PMC9932487 DOI: 10.1016/j.isci.2023.105984] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Revised: 10/12/2022] [Accepted: 01/11/2023] [Indexed: 01/15/2023] Open
Abstract
By providing an ideal environment for healing, biomaterials can be designed to facilitate and encourage wound regeneration. As the wound healing process is complex, there needs to be consideration for the cell types playing major roles, such as fibroblasts. As a major cell type in the dermis, fibroblasts have a large impact on the processes and outcomes of wound healing. Prevopisly, conjugating the angiopoietin-1 derived Q-peptide (QHREDGS) to a collagen-chitosan hydrogel created a biomaterial with in vivo success in accelerating wound healing. This study utilized solvent cast Q-peptide conjugated collagen-chitosan seeded with fibroblast monolayers to investigate the direct impact of the material on this major cell type. After 24 h, fibroblasts had a significant change in release of anti-inflammatory, pro-healing, and ECM deposition cytokines, with demonstrated immunomodulatory effects on macrophages and upregulated expression of critical wound healing genes.
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Affiliation(s)
- Katrina Vizely
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, ON M5S 3E5, Canada
| | - Karl T. Wagner
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, ON M5S 3E5, Canada,Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, ON M5S 3G9, Canada
| | - Serena Mandla
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, ON M5S 3G9, Canada
| | - Dakota Gustafson
- Toronto General Hospital Research Institute, University Health Network, Toronto,ON M5G 2C4, Canada,Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Jason E. Fish
- Toronto General Hospital Research Institute, University Health Network, Toronto,ON M5G 2C4, Canada,Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Milica Radisic
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, ON M5S 3E5, Canada,Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, ON M5S 3G9, Canada,Toronto General Hospital Research Institute, University Health Network, Toronto,ON M5G 2C4, Canada,Corresponding author
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Abstract
Cardiovascular diseases are the leading cause of death worldwide. Discovering new therapies to treat heart disease requires improved understanding of cardiac physiology at a cellular level. Extracellular vesicles (EVs) are plasma membrane-bound nano- and microparticles secreted by cells and known to play key roles in intercellular communication, often through transfer of biomolecular cargo. Advances in EV research have established techniques for EV isolation from tissue culture media or biofluids, as well as standards for quantitation and biomolecular characterization. EVs released by cardiac cells are known to be involved in regulating cardiac physiology as well as in the progression of myocardial diseases. Due to difficulty accessing the heart in vivo, advanced in vitro cardiac 'tissues-on-a-chip' have become a recent focus for studying EVs in the heart. These physiologically relevant models are producing new insight into the role of EVs in cardiac physiology and disease while providing a useful platform for screening novel EV-based therapeutics for cardiac tissue regeneration post-injury. Numerous hurdles have stalled the clinical translation of EV therapeutics for heart patients, but tissue-on-a-chip models are playing an important role in bridging the translational gap, improving mechanistic understanding of EV signalling in cardiac physiology, disease, and repair.
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Affiliation(s)
- Karl T Wagner
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 27 King's College Circle, Toronto, Ontario, Canada M5S 1A1
| | - Milica Radisic
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 27 King's College Circle, Toronto, Ontario, Canada M5S 1A1
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6
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Wagner KT, Nash TR, Liu B, Vunjak-Novakovic G, Radisic M. Extracellular Vesicles in Cardiac Regeneration: Potential Applications for Tissues-on-a-Chip. Trends Biotechnol 2020; 39:755-773. [PMID: 32958383 DOI: 10.1016/j.tibtech.2020.08.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2020] [Revised: 08/10/2020] [Accepted: 08/11/2020] [Indexed: 12/26/2022]
Abstract
Strategies to regenerate cardiac tissue postinjury are limited and heart transplantation remains the only 'cure' for a failing heart. Extracellular vesicles (EVs), membrane-bound cell secretions important in intercellular signaling, have been shown to play a crucial role in regulating heart function. A mechanistic understanding of the role of EVs in the heart remains elusive due to the challenges in studying the native human heart. Tissue-on-a-chip platforms, comprising functional, physiologically relevant human tissue models, are an emerging technology that has yet to be fully applied to the study of EVs. In this review, we summarize recent advances in cardiac tissue-on-a-chip (CTC) platforms and discuss how they are uniquely situated to advance our understanding of EVs in cardiac disease and regeneration.
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Affiliation(s)
- Karl T Wagner
- 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
| | - Trevor R Nash
- Department of Medicine, Columbia University, New York, NY, USA; Vagelos College of Physicians and Surgeons, Columbia University, New York, NY, USA
| | - Bohao Liu
- Department of Medicine, Columbia University, New York, NY, USA; Vagelos College of Physicians and Surgeons, Columbia University, New York, NY, USA
| | - Gordana Vunjak-Novakovic
- Department of Medicine, Columbia University, New York, NY, USA; Department of Biomedical Engineering, Columbia University, New York, NY, USA.
| | - 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, Toronto, ON, Canada.
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7
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Svystonyuk DA, Mewhort HEM, Hassanabad AF, Heydari B, Mikami Y, Turnbull JD, Teng G, Belke DD, Wagner KT, Tarraf SA, DiMartino ES, White JA, Flewitt JA, Cheung M, Guzzardi DG, Kang S, Fedak PWM. Acellular bioscaffolds redirect cardiac fibroblasts and promote functional tissue repair in rodents and humans with myocardial injury. Sci Rep 2020; 10:9459. [PMID: 32528051 PMCID: PMC7289874 DOI: 10.1038/s41598-020-66327-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Accepted: 05/19/2020] [Indexed: 01/31/2023] Open
Abstract
Coronary heart disease is a leading cause of death. Tissue remodeling and fibrosis results in cardiac pump dysfunction and ischemic heart failure. Cardiac fibroblasts may rebuild damaged tissues when prompted by suitable environmental cues. Here, we use acellular biologic extracellular matrix scaffolds (bioscaffolds) to stimulate pathways of muscle repair and restore tissue function. We show that acellular bioscaffolds with bioinductive properties can redirect cardiac fibroblasts to rebuild microvascular networks and avoid tissue fibrosis. Specifically, when human cardiac fibroblasts are combined with bioactive scaffolds, gene expression is upregulated and paracrine mediators are released that promote vasculogenesis and prevent scarring. We assess these properties in rodents with myocardial infarction and observe bioscaffolds to redirect fibroblasts, reduce tissue fibrosis and prevent maladaptive structural remodeling. Our preclinical data confirms that acellular bioscaffold therapy provides an appropriate microenvironment to stimulate pathways of functional repair. We translate our observations to patients with coronary heart disease by conducting a first-in-human observational cohort study. We show that bioscaffold therapy is associated with improved perfusion of infarcted myocardium, reduced myocardial scar burden, and reverse structural remodeling. We establish that clinical use of acellular bioscaffolds is feasible and offers a new frontier to enhance surgical revascularization of ischemic heart muscle.
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Affiliation(s)
- Daniyil A Svystonyuk
- Section of Cardiac Surgery, Department of Cardiac Sciences, Cumming School of Medicine, Libin Cardiovascular Institute, University of Calgary, Calgary, Alberta, Canada
| | - Holly E M Mewhort
- Section of Cardiac Surgery, Department of Cardiac Sciences, Cumming School of Medicine, Libin Cardiovascular Institute, University of Calgary, Calgary, Alberta, Canada
| | - Ali Fatehi Hassanabad
- Section of Cardiac Surgery, Department of Cardiac Sciences, Cumming School of Medicine, Libin Cardiovascular Institute, University of Calgary, Calgary, Alberta, Canada
| | - Bobak Heydari
- Department of Radiology, Cumming School of Medicine, Stephenson Cardiac Imaging Centre, Libin Cardiovascular Institute, University of Calgary, Calgary, Alberta, Canada
| | - Yoko Mikami
- Department of Radiology, Cumming School of Medicine, Stephenson Cardiac Imaging Centre, Libin Cardiovascular Institute, University of Calgary, Calgary, Alberta, Canada
| | - Jeannine D Turnbull
- Section of Cardiac Surgery, Department of Cardiac Sciences, Cumming School of Medicine, Libin Cardiovascular Institute, University of Calgary, Calgary, Alberta, Canada
| | - Guoqi Teng
- Section of Cardiac Surgery, Department of Cardiac Sciences, Cumming School of Medicine, Libin Cardiovascular Institute, University of Calgary, Calgary, Alberta, Canada
| | - Darrell D Belke
- Section of Cardiac Surgery, Department of Cardiac Sciences, Cumming School of Medicine, Libin Cardiovascular Institute, University of Calgary, Calgary, Alberta, Canada
| | - Karl T Wagner
- Section of Cardiac Surgery, Department of Cardiac Sciences, Cumming School of Medicine, Libin Cardiovascular Institute, University of Calgary, Calgary, Alberta, Canada
| | - Samar A Tarraf
- Department of Civil Engineering, Libin Cardiovascular Institute and Centre for Bioengineering Research and Education, University of Calgary, Calgary, Alberta, Canada
| | - Elena S DiMartino
- Department of Civil Engineering, Libin Cardiovascular Institute and Centre for Bioengineering Research and Education, University of Calgary, Calgary, Alberta, Canada
| | - James A White
- Department of Radiology, Cumming School of Medicine, Stephenson Cardiac Imaging Centre, Libin Cardiovascular Institute, University of Calgary, Calgary, Alberta, Canada
| | - Jacqueline A Flewitt
- Department of Radiology, Cumming School of Medicine, Stephenson Cardiac Imaging Centre, Libin Cardiovascular Institute, University of Calgary, Calgary, Alberta, Canada
| | - Matthew Cheung
- Department of Radiology, Cumming School of Medicine, Stephenson Cardiac Imaging Centre, Libin Cardiovascular Institute, University of Calgary, Calgary, Alberta, Canada
| | - David G Guzzardi
- Section of Cardiac Surgery, Department of Cardiac Sciences, Cumming School of Medicine, Libin Cardiovascular Institute, University of Calgary, Calgary, Alberta, Canada
| | - Sean Kang
- Section of Cardiac Surgery, Department of Cardiac Sciences, Cumming School of Medicine, Libin Cardiovascular Institute, University of Calgary, Calgary, Alberta, Canada
| | - Paul W M Fedak
- Section of Cardiac Surgery, Department of Cardiac Sciences, Cumming School of Medicine, Libin Cardiovascular Institute, University of Calgary, Calgary, Alberta, Canada.
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8
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Abstract
Nine of 212 cases of traumatic anterior shoulder dislocations occurred in children with clearly open epiphyses (4.7% incidence). All cases associated with psychological or physical abnormalities were excluded. A high recurrence rate of 80% (8 of 10) was noted requiring operative intervention. Two of the three remaining unoperated cases had a history of "subluxation" after their initial dislocation.
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