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Knight WE, Ali HR, Nakano SJ, Wilson CE, Walker LA, Woulfe KC. Ex vivo Methods for Measuring Cardiac Muscle Mechanical Properties. Front Physiol 2021; 11:616996. [PMID: 33488406 PMCID: PMC7820907 DOI: 10.3389/fphys.2020.616996] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Accepted: 12/10/2020] [Indexed: 11/13/2022] Open
Abstract
Cardiovascular disease continues to be the leading cause of morbidity and mortality in the United States and thousands of manuscripts each year are aimed at elucidating mechanisms underlying cardiac disease. The methods for quantifying cardiac performance are quite varied, with each technique assessing unique features of cardiac muscle mechanical properties. Accordingly, in this review, we discuss current ex vivo methods for quantifying cardiac muscle performance, highlighting what can be learned from each method, and how each technique can be used in conjunction to complement others for a more comprehensive understanding of cardiac function. Importantly, cardiac function can be assessed at several different levels, from the whole organ down to individual protein-protein interactions. Here, we take a reductionist view of methods that are commonly used to measure the distinct aspects of cardiac mechanical function, beginning with whole heart preparations and finishing with the in vitro motility assay. While each of the techniques are individually well-documented in the literature, there is a significant need for a comparison of the techniques, delineating the mechanical parameters that can are best measured with each technique, as well as the strengths and weaknesses inherent to each method. Additionally, we will consider complementary techniques and how these methods can be used in combination to improve our understanding of cardiac mechanical function. By presenting each of these methods, with their strengths and limitations, in a single manuscript, this review will assist cardiovascular biologists in understanding the existing literature on cardiac mechanical function, as well as designing future experiments.
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Affiliation(s)
- Walter E Knight
- Department of Medicine, Division of Cardiology, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | - Hadi R Ali
- Department of Medicine, Division of Cardiology, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | - Stephanie J Nakano
- Department of Pediatrics, Division of Cardiology, Children's Hospital, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | - Cortney E Wilson
- Department of Medicine, Division of Cardiology, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | - Lori A Walker
- Department of Medicine, Division of Cardiology, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | - Kathleen C Woulfe
- Department of Medicine, Division of Cardiology, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
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2
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A Multi-Mode System for Myocardial Functional and Physiological Assessment during Ex Situ Heart Perfusion. THE JOURNAL OF EXTRA-CORPOREAL TECHNOLOGY 2020; 52:303-313. [PMID: 33343033 DOI: 10.1182/ject-2000034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 01/12/2020] [Accepted: 10/20/2020] [Indexed: 11/20/2022]
Abstract
Ex situ heart perfusion (ESHP) has proven to be an important and valuable step toward better preservation of donor hearts for heart transplantation. Currently, few ESHP systems allow for a convenient functional and physiological evaluation of the heart. We sought to establish a simple system that provides functional and physiological assessment of the heart during ESHP. The ESHP circuit consists of an oxygenator, a heart-lung machine, a heater-cooler unit, an anesthesia gas blender, and a collection funnel. Female Yorkshire pig hearts (n = 10) had del Nido cardioplegia (4°C) administered, excised, and attached to the perfusion system. Hearts were perfused retrogradely into the aortic root for 2 hours before converting the system to an isovolumic mode or a working mode for further 2 hours. Blood samples were analyzed to measure metabolic parameters. During the isovolumic mode (n = 5), a balloon inserted in the left ventricular (LV) cavity was inflated so that an end-diastolic pressure of 6-8 mmHg was reached. During the working mode (n = 5), perfusion in the aortic root was redirected into left atrium (LA) using a compliance chamber which maintained an LA pressure of 6-8 mmHg. Another compliance chamber was used to provide an afterload of 40-50 mmHg. Hemodynamic and metabolic conditions remained stable and consistent for a period of 4 hours of ESHP in both isovolumic mode (LV developed pressure: 101.0 ± 3.5 vs. 99.7 ± 6.8 mmHg, p = .979, at 2 and 4 hours, respectively) and working mode (LV developed pressure: 91.0 ± 2.6 vs. 90.7 ± 2.5 mmHg, p = .942, at 2 and 4 hours, respectively). The present study proposed a novel ESHP system that enables comprehensive functional and metabolic assessment of large mammalian hearts. This system allowed for stable myocardial function for up to 4 hours of perfusion, which would offer great potential for the development of translational therapeutic protocols to improve dysfunctional donated hearts.
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3
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Pitoulis FG, Watson SA, Perbellini F, Terracciano CM. Myocardial slices come to age: an intermediate complexity in vitro cardiac model for translational research. Cardiovasc Res 2020; 116:1275-1287. [PMID: 31868875 PMCID: PMC7243278 DOI: 10.1093/cvr/cvz341] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Revised: 10/31/2019] [Accepted: 12/19/2019] [Indexed: 12/17/2022] Open
Abstract
Although past decades have witnessed significant reductions in mortality of heart failure together with advances in our understanding of its cellular, molecular, and whole-heart features, a lot of basic cardiac research still fails to translate into clinical practice. In this review we examine myocardial slices, a novel model in the translational arena. Myocardial slices are living ultra-thin sections of heart tissue. Slices maintain the myocardium's native function (contractility, electrophysiology) and structure (multicellularity, extracellular matrix) and can be prepared from animal and human tissue. The discussion begins with the history and current advances in the model, the different interlaboratory methods of preparation and their potential impact on results. We then contextualize slices' advantages and limitations by comparing it with other cardiac models. Recently, sophisticated methods have enabled slices to be cultured chronically in vitro while preserving the functional and structural phenotype. This is more timely now than ever where chronic physiologically relevant in vitro platforms for assessment of therapeutic strategies are urgently needed. We interrogate the technological developments that have permitted this, their limitations, and future directions. Finally, we look into the general obstacles faced by the translational field, and how implementation of research systems utilizing slices could help in resolving these.
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Affiliation(s)
- Fotios G Pitoulis
- Laboratory of Cell Electrophysiology, Department of Myocardial Function, Imperial College London, National Heart and Lung Institute, 4th Floor ICTEM Building Hammersmith Hospital, Du Cane Road, London W12 0NN, UK
| | - Samuel A Watson
- Laboratory of Cell Electrophysiology, Department of Myocardial Function, Imperial College London, National Heart and Lung Institute, 4th Floor ICTEM Building Hammersmith Hospital, Du Cane Road, London W12 0NN, UK
| | - Filippo Perbellini
- Laboratory of Cell Electrophysiology, Department of Myocardial Function, Imperial College London, National Heart and Lung Institute, 4th Floor ICTEM Building Hammersmith Hospital, Du Cane Road, London W12 0NN, UK
- Hannover Medical School, Institute of Molecular and Translational Therapeutic Strategies, Hannover, Germany
| | - Cesare M Terracciano
- Laboratory of Cell Electrophysiology, Department of Myocardial Function, Imperial College London, National Heart and Lung Institute, 4th Floor ICTEM Building Hammersmith Hospital, Du Cane Road, London W12 0NN, UK
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4
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Pitoulis FG, Terracciano CM. Heart Plasticity in Response to Pressure- and Volume-Overload: A Review of Findings in Compensated and Decompensated Phenotypes. Front Physiol 2020; 11:92. [PMID: 32116796 PMCID: PMC7031419 DOI: 10.3389/fphys.2020.00092] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Accepted: 01/27/2020] [Indexed: 12/20/2022] Open
Abstract
The adult human heart has an exceptional ability to alter its phenotype to adapt to changes in environmental demand. This response involves metabolic, mechanical, electrical, and structural alterations, and is known as cardiac plasticity. Understanding the drivers of cardiac plasticity is essential for development of therapeutic agents. This is particularly important in contemporary cardiology, which uses treatments with peripheral effects (e.g., on kidneys, adrenal glands). This review focuses on the effects of different hemodynamic loads on myocardial phenotype. We examine mechanical scenarios of pressure- and volume overload, from the initial insult, to compensated, and ultimately decompensated stage. We discuss how different hemodynamic conditions occur and are underlined by distinct phenotypic and molecular changes. We complete the review by exploring how current basic cardiac research should leverage available cardiac models to study mechanical load in its different presentations.
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Pharmacological Overview of the BGP-15 Chemical Agent as a New Drug Candidate for the Treatment of Symptoms of Metabolic Syndrome. Molecules 2020; 25:molecules25020429. [PMID: 31968693 PMCID: PMC7024383 DOI: 10.3390/molecules25020429] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 01/08/2020] [Accepted: 01/15/2020] [Indexed: 02/06/2023] Open
Abstract
BGP-15 is a new insulin sensitizer drug candidate, which was developed by Hungarian researchers. In recent years, numerous research groups have studied its beneficial effects. It is effective in the treatment of insulin resistance and it has protective effects in Duchenne muscular dystrophy, diastolic dysfunction, tachycardia, heart failure, and atrial fibrillation, and it can alleviate cardiotoxicity. BGP-15 exhibits chemoprotective properties in different cytostatic therapies, and has also proven to be photoprotective. It can additionally have advantageous effects in mitochondrial-stress-related diseases. Although the precise mechanism of the effect is still unknown to us, we know that the molecule is a PARP inhibitor, chaperone co-inducer, reduces ROS production, and is able to remodel the organization of cholesterol-rich membrane domains. In the following review, our aim was to summarize the investigated molecular mechanisms and pharmacological effects of this potential API. The main objective was to present the wide pharmacological potentials of this chemical agent.
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6
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Jett SV, Hudson LT, Baumwart R, Bohnstedt BN, Mir A, Burkhart HM, Holzapfel GA, Wu Y, Lee CH. Integration of polarized spatial frequency domain imaging (pSFDI) with a biaxial mechanical testing system for quantification of load-dependent collagen architecture in soft collagenous tissues. Acta Biomater 2020; 102:149-168. [PMID: 31734412 PMCID: PMC8101699 DOI: 10.1016/j.actbio.2019.11.028] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2019] [Revised: 11/11/2019] [Accepted: 11/12/2019] [Indexed: 12/30/2022]
Abstract
Collagen fiber networks provide the structural strength of tissues, such as tendons, skin and arteries. Quantifying the fiber architecture in response to mechanical loads is essential towards a better understanding of the tissue-level mechanical behaviors, especially in assessing disease-driven functional changes. To enable novel investigations into these load-dependent fiber structures, a polarized spatial frequency domain imaging (pSFDI) device was developed and, for the first time, integrated with a biaxial mechanical testing system. The integrated instrument is capable of a wide-field quantification of the fiber orientation and the degree of optical anisotropy (DOA), representing the local degree of fiber alignment. The opto-mechanical instrument''s performance was assessed through uniaxial loading on tendon tissues with known collagen fiber microstructures. Our results revealed that the bulk fiber orientation angle of the tendon tissue changed minimally with loading (median ± 0.5*IQR of 52.7° ± 3.3° and 51.9° ± 3.3° under 0 and 3% longitudinal strains, respectively), whereas on a micro-scale, the fibers became better aligned with the direction of loading: the DOA (mean ± SD) increased from 0.149 ± 0.032 to 0.198 ± 0.056 under 0 and 3% longitudinal strains, respectively, p < 0.001. The integrated instrument was further applied to study two representative mitral valve anterior leaflet (MVAL) tissues subjected to various biaxial loads. The fiber orientations within these representative MVAL tissue specimens demonstrated noticeable heterogeneity, with the local fiber orientations dependent upon the sample, the spatial and transmural locations, and the applied loading. Our results also showed that fibers were generally better aligned under equibiaxial (DOA = 0.089 ± 0.036) and circumferentially-dominant loading (DOA = 0.086 ± 0.037) than under the radially-dominant loading (DOA = 0.077 ± 0.034), indicating circumferential predisposition. These novel findings exemplify a deeper understanding of the load-dependent collagen fiber microstructures obtained through the use of the integrated opto-mechanical instrument. STATEMENT OF SIGNIFICANCE: In this study, a novel quantitative opto-mechanical system was developed by combining a polarized Spatial Frequency Domain Imaging (pSFDI) device with a biaxial mechanical tester. The integrated system was used to quantify the load-dependent collagen fiber microstructures in representative tendon and mitral valve anterior leaflet (MVAL) tissues. Our results revealed that MVAL's fiber architectures exhibited load-dependent spatial and transmural heterogeneities, suggesting further microstructural complexity than previously reported in heart valve tissues. These novel findings were possible through the system's ability to, for the first time, capture the load-dependent collagen architecture in the mitral valve anterior leaflet tissue over a wide field of view (e.g., 10 × 10 mm for the MVAL tissue specimens). Such capabilities afford unique future opportunities to improve patient outcomes through concurrent mechanical and microstructural assessments of healthy and diseased tissues in conditions such as heart valve regurgitation and calcification.
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Affiliation(s)
- Samuel V Jett
- Biomechanics and Biomaterials Design Laboratory, School of Aerospace and Mechanical Engineering, Affiliated Faculty Member, Institute for Biomedical Engineering, Science, and Technology, The University of Oklahoma, 865 Asp Ave., Felgar Hall Rm. 219C, Norman, OK 73019-3609, United States
| | - Luke T Hudson
- Biomechanics and Biomaterials Design Laboratory, School of Aerospace and Mechanical Engineering, Affiliated Faculty Member, Institute for Biomedical Engineering, Science, and Technology, The University of Oklahoma, 865 Asp Ave., Felgar Hall Rm. 219C, Norman, OK 73019-3609, United States
| | - Ryan Baumwart
- Center for Veterinary Health Sciences, Oklahoma State University, 2065 W. Farm Rd., Stillwater, OK 74078, United States
| | - Bradley N Bohnstedt
- Department of Neurosurgery, The University of Oklahoma Health Sciences Center, 1000 N Lincoln Blvd #400, Oklahoma City, OK 73104, United States
| | - Arshid Mir
- Division of Pediatric Cardiology, Department of Pediatrics, The University of Oklahoma Health Sciences Center, 1200 Children's Ave., Suite 2F, Oklahoma City, OK 73104, United States
| | - Harold M Burkhart
- Division of Cardiothoracic Surgery, Department of Surgery, The University of Oklahoma Health Sciences Center, 800 Stanton L. Young Blvd. Suite 9000, Oklahoma City, OK 73104, United States
| | - Gerhard A Holzapfel
- Institute of Biomechanics, Graz University of Technology, Stremayrgasse 16/2 8010 Graz, Austria; Department of Structural Engineering, Norwegian University of Science and Technology (NTNU), 7491 Trondheim, Norway
| | - Yi Wu
- Biomechanics and Biomaterials Design Laboratory, School of Aerospace and Mechanical Engineering, Affiliated Faculty Member, Institute for Biomedical Engineering, Science, and Technology, The University of Oklahoma, 865 Asp Ave., Felgar Hall Rm. 219C, Norman, OK 73019-3609, United States
| | - Chung-Hao Lee
- Biomechanics and Biomaterials Design Laboratory, School of Aerospace and Mechanical Engineering, Affiliated Faculty Member, Institute for Biomedical Engineering, Science, and Technology, The University of Oklahoma, 865 Asp Ave., Felgar Hall Rm. 219C, Norman, OK 73019-3609, United States; Institute for Biomedical Engineering, Science and Technology, The University of Oklahoma, 202 West Boyd St., Norman, OK 73019, United States.
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7
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Gellner B, Xin L, Ribeiro RVP, Bissoondath V, Lu P, Adamson MB, Yu F, Paradiso E, Zu J, Simmons CA, Badiwala MV. The Implementation of an Adjustable Afterload Module for Ex Situ Heart Perfusion. Cardiovasc Eng Technol 2019; 11:96-110. [PMID: 31797263 DOI: 10.1007/s13239-019-00447-w] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Accepted: 11/24/2019] [Indexed: 12/23/2022]
Abstract
PURPOSE Windkessel impedance analysis has proven to be an effective technique for instituting artificial afterload on ex situ hearts. Traditional fixed parameter afterload modules, however, are unable to handle the changing contractile conditions associated with prolonged ex situ heart perfusion. In this paper, an adjustable afterload module is described comprising of three fully adjustable sub-components: a systemic resistor, a proximal resistor and a compliance chamber. METHODS Using a centrifugal pump, the systemic resistor and compliance chamber were subjected to testing across their operating ranges, whereby the predictability of resistance and compliance values was evaluated. The components were then assembled, and the full module tested on three separate porcine hearts perfused for 6 h with success defined by the ability to maintain physiological systolic and diastolic aortic pressures across flow rate variability. RESULTS For both the systemic resistor and compliance chamber, experimental measurements agreed with their theoretical equivalents, with coefficients of determination of 0.99 and 0.97 for the systemic resistor and compliance chamber, respectively. During ex situ perfusion, overall 95% confidence intervals demonstrate that physiological systolic (95-96.21 mmHg) and diastolic (26.8-28.8 mmHg) pressures were successfully maintained, despite large variability in aortic flow. Left ventricular contractile parameters, were found to be in line with those in previous studies, suggesting the afterload module has no detrimental impact on functional preservation. CONCLUSIONS We conclude that due to the demonstrable control of our afterload module, we can maintain physiological aortic pressures in a passive afterload working mode across prolonged perfusion periods, enabling effective perfusion regardless of contractile performance.
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Affiliation(s)
- Bryan Gellner
- Department of Mechanical & Industrial Engineering, University of Toronto, Toronto, ON, Canada
- Translational Biology & Engineering Program, Ted Rogers Centre for Heart Research, Toronto, ON, Canada
| | - Liming Xin
- Department of Mechanical & Industrial Engineering, University of Toronto, Toronto, ON, Canada
- Division of Cardiovascular Surgery, Toronto General Hospital, University Health Network, Toronto, ON, Canada
- State Key Laboratory of Mechanical Transmissions, Chongqing University, Chongqing, China
| | - Roberto Vanin Pinto Ribeiro
- Division of Cardiovascular Surgery, Toronto General Hospital, University Health Network, Toronto, ON, Canada
- Institute of Medical Science, University of Toronto, Toronto, ON, Canada
| | - Ved Bissoondath
- Division of Cardiovascular Surgery, Toronto General Hospital, University Health Network, Toronto, ON, Canada
| | - Pengzhou Lu
- Department of Mechanical & Industrial Engineering, University of Toronto, Toronto, ON, Canada
- Division of Cardiovascular Surgery, Toronto General Hospital, University Health Network, Toronto, ON, Canada
| | - Mitchell B Adamson
- Division of Cardiovascular Surgery, Toronto General Hospital, University Health Network, Toronto, ON, Canada
- Institute of Medical Science, University of Toronto, Toronto, ON, Canada
| | - Frank Yu
- Division of Cardiovascular Surgery, Toronto General Hospital, University Health Network, Toronto, ON, Canada
| | - Emanuela Paradiso
- Department of Anesthesia and Pain Management, Toronto General Hospital, University Health Network, Toronto, ON, Canada
| | - Jean Zu
- Department of Mechanical & Industrial Engineering, University of Toronto, Toronto, ON, Canada
| | - Craig A Simmons
- Department of Mechanical & Industrial Engineering, University of Toronto, Toronto, ON, Canada.
- Translational Biology & Engineering Program, Ted Rogers Centre for Heart Research, Toronto, ON, Canada.
- Institute of Biomaterials & Biomedical Engineering, University of Toronto, Toronto, ON, Canada.
| | - Mitesh V Badiwala
- Division of Cardiovascular Surgery, Toronto General Hospital, University Health Network, Toronto, ON, Canada
- Department of Surgery, University of Toronto, Toronto, ON, Canada
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8
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Gellner B, Xin L, Pinto Ribeiro RV, Bissoondath V, Adamson MB, Yu F, Lu P, Paradiso E, Mbadjeu Hondjeu AR, Simmons CA, Badiwala MV. The implementation of physiological afterload during ex situ heart perfusion augments prediction of posttransplant function. Am J Physiol Heart Circ Physiol 2019; 318:H25-H33. [PMID: 31774696 DOI: 10.1152/ajpheart.00427.2019] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Ex situ heart perfusion (ex situ heart perfusion) is an emerging technique that aims to increase the number of organs available for transplantation by augmenting both donor heart preservation and evaluation. Traditionally, ex situ heart perfusion has been performed in an unloaded Langendorff mode, though more recently groups have begun to use pump-supported working mode (PSWM) and passive afterload working mode (PAWM) to enable contractile evaluation during ex situ heart perfusion. To this point, however, neither the predictive effectiveness of the two working modes nor the predictive power of individual contractile parameters has been analyzed. In this article, we use our previously described system to analyze the predictive relevance of a multitude of contractile parameters measured in each working mode. Ten porcine hearts were excised and perfused ex situ in Langendorff mode for 4 h, evaluated using pressure-volume catheterization in both PSWM and PAWM, and transplanted into size-matched recipient pigs. After 3 h, hearts were weaned from cardiopulmonary bypass and evaluated. When correlating posttransplant measurements to their ex situ counterparts, we report that parameters measured in both modes show sufficient power (Spearman rank coefficient > 0.7) in predicting global posttransplant function, characterized by cardiac index and preload recruitable stroke work. For the prediction of specific posttransplant systolic and diastolic function, however, a large discrepancy between the two working modes was observed. With 9 of 10 measured posttransplant parameters showing stronger correlation with counterparts measured in PAWM, it is concluded that PAWM allows for a more detailed and nuanced prediction of posttransplant function than can be made in PSWM.NEW & NOTEWORTHY Ex situ heart perfusion has been proposed as a means to augment the organ donor pool by improving organ preservation and evaluation between donation and transplantation. Using our multimodal perfusion system, we analyzed the impact of using a "passive afterload working mode" for functional evaluation as compared with the more traditional "pump-supported working mode." Our data suggests that passive afterload working mode allows for a more nuanced prediction of posttransplant function in porcine hearts.
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Affiliation(s)
- Bryan Gellner
- Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, Ontario, Canada.,Translational Biology and Engineering Program, Ted Rogers Centre for Heart Research, Toronto, Ontario, Canada
| | - Liming Xin
- Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, Ontario, Canada.,Division of Cardiovascular Surgery, Toronto General Hospital, University Health Network, Toronto, Ontario, Canada
| | - Roberto Vanin Pinto Ribeiro
- Division of Cardiovascular Surgery, Toronto General Hospital, University Health Network, Toronto, Ontario, Canada.,Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada
| | - Ved Bissoondath
- Division of Cardiovascular Surgery, Toronto General Hospital, University Health Network, Toronto, Ontario, Canada
| | - Mitchell B Adamson
- Division of Cardiovascular Surgery, Toronto General Hospital, University Health Network, Toronto, Ontario, Canada.,Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada
| | - Frank Yu
- Division of Cardiovascular Surgery, Toronto General Hospital, University Health Network, Toronto, Ontario, Canada
| | - Pengzhou Lu
- Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, Ontario, Canada.,Division of Cardiovascular Surgery, Toronto General Hospital, University Health Network, Toronto, Ontario, Canada
| | - Emanuela Paradiso
- Department of Anesthesia and Pain Management, Toronto General Hospital, University Health Network, Toronto, Ontario, Canada
| | - Arnaud Romeo Mbadjeu Hondjeu
- Department of Anesthesia and Pain Management, Toronto General Hospital, University Health Network, Toronto, Ontario, Canada
| | - Craig A Simmons
- Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, Ontario, Canada.,Translational Biology and Engineering Program, Ted Rogers Centre for Heart Research, Toronto, Ontario, Canada.,Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada
| | - Mitesh V Badiwala
- Division of Cardiovascular Surgery, Toronto General Hospital, University Health Network, Toronto, Ontario, Canada.,Department of Surgery, University of Toronto, Toronto, Ontario, Canada
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9
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Swift LM, Jaimes R, McCullough D, Burke M, Reilly M, Maeda T, Zhang H, Ishibashi N, Rogers JM, Posnack NG. Optocardiography and Electrophysiology Studies of Ex Vivo Langendorff-perfused Hearts. J Vis Exp 2019. [PMID: 31762469 DOI: 10.3791/60472] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Small animal models are most commonly used in cardiovascular research due to the availability of genetically modified species and lower cost compared to larger animals. Yet, larger mammals are better suited for translational research questions related to normal cardiac physiology, pathophysiology, and preclinical testing of therapeutic agents. To overcome the technical barriers associated with employing a larger animal model in cardiac research, we describe an approach to measure physiological parameters in an isolated, Langendorff-perfused piglet heart. This approach combines two powerful experimental tools to evaluate the state of the heart: electrophysiology (EP) study and simultaneous optical mapping of transmembrane voltage and intracellular calcium using parameter sensitive dyes (RH237, Rhod2-AM). The described methodologies are well suited for translational studies investigating the cardiac conduction system, alterations in action potential morphology, calcium handling, excitation-contraction coupling and the incidence of cardiac alternans or arrhythmias.
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Affiliation(s)
- Luther M Swift
- Sheikh Zayed Institute for Pediatric Surgical Innovation, Children's National Hospital; Children's National Heart Institute, Children's National Hospital
| | - Rafael Jaimes
- Sheikh Zayed Institute for Pediatric Surgical Innovation, Children's National Hospital; Children's National Heart Institute, Children's National Hospital
| | - Damon McCullough
- Sheikh Zayed Institute for Pediatric Surgical Innovation, Children's National Hospital; Children's National Heart Institute, Children's National Hospital
| | - Morgan Burke
- Sheikh Zayed Institute for Pediatric Surgical Innovation, Children's National Hospital; Children's National Heart Institute, Children's National Hospital
| | - Marissa Reilly
- Sheikh Zayed Institute for Pediatric Surgical Innovation, Children's National Hospital; Children's National Heart Institute, Children's National Hospital
| | - Takuya Maeda
- Sheikh Zayed Institute for Pediatric Surgical Innovation, Children's National Hospital; Children's National Heart Institute, Children's National Hospital; Center for Neuroscience Research, Children's National Hospital
| | - Hanyu Zhang
- Department of Biomedical Engineering, School of Engineering, University of Alabama at Birmingham
| | - Nobuyuki Ishibashi
- Sheikh Zayed Institute for Pediatric Surgical Innovation, Children's National Hospital; Children's National Heart Institute, Children's National Hospital; Center for Neuroscience Research, Children's National Hospital
| | - Jack M Rogers
- Department of Biomedical Engineering, School of Engineering, University of Alabama at Birmingham
| | - Nikki Gillum Posnack
- Sheikh Zayed Institute for Pediatric Surgical Innovation, Children's National Hospital; Children's National Heart Institute, Children's National Hospital; Department of Pediatrics, Department of Pharmacology & Physiology, School of Medicine and Health Sciences, George Washington University;
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10
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Bishawi M, Roan JN, Milano CA, Daneshmand MA, Schroder JN, Chiang Y, Lee FH, Brown ZD, Nevo A, Watson MJ, Rowell T, Paul S, Lezberg P, Walczak R, Bowles DE. A normothermic ex vivo organ perfusion delivery method for cardiac transplantation gene therapy. Sci Rep 2019; 9:8029. [PMID: 31142753 PMCID: PMC6541710 DOI: 10.1038/s41598-019-43737-y] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Accepted: 04/27/2019] [Indexed: 01/21/2023] Open
Abstract
Clinically, both percutaneous and surgical approaches to deliver viral vectors to the heart either have resulted in therapeutically inadequate levels of transgene expression or have raised safety concerns associated with extra-cardiac delivery. Recent developments in the field of normothermic ex vivo cardiac perfusion storage have now created opportunities to overcome these limitations and safety concerns of cardiac gene therapy. This study examined the feasibility of ex vivo perfusion as an approach to deliver a viral vector to a donor heart during storage and the resulting bio distribution and expression levels of the transgene in the recipient post-transplant. The influence of components (proprietary solution, donor blood, and ex vivo circuitry tubing and oxygenators) of the Organ Care System (OC) (TransMedics, Inc., Andover MA) on viral vector transduction was examined using a cell-based luciferase assay. Our ex vivo perfusion strategy, optimized for efficient Adenoviral vector transduction, was utilized to deliver 5 × 1013 total viral particles of an Adenoviral firefly luciferase vector with a cytomegalovirus (CMV) promotor to porcine donor hearts prior to heterotopic implantation. We have evaluated the overall levels of expression, protein activity, as well as the bio distribution of the firefly luciferase protein in a series of three heart transplants at a five-day post-transplant endpoint. The perfusion solution and the ex vivo circuitry did not influence viral vector transduction, but the serum or plasma fractions of the donor blood significantly inhibited viral vector transduction. Thus, subsequent gene delivery experiments to the explanted porcine heart utilized an autologous blood recovery approach to remove undesired plasma or serum components of the donor blood prior to its placement into the circuit. Enzymatic assessment of luciferase activity in tissues (native heart, allograft, liver etc.) obtained post-transplant day five revealed wide-spread and robust luciferase activity in all regions of the allograft (right and left atria, right and left ventricles, coronary arteries) compared to the native recipient heart. Importantly, luciferase activity in recipient heart, liver, lung, spleen, or psoas muscle was within background levels. Similar to luciferase activity, the luciferase protein expression in the allograft appeared uniform and robust across all areas of the myocardium as well as in the coronary arteries. Importantly, despite high copy number of vector genomic DNA in transplanted heart tissue, there was no evidence of vector DNA in either the recipient’s native heart or liver. Overall we demonstrate a simple protocol to achieve substantial, global gene delivery and expression isolated to the cardiac allograft. This introduces a novel method of viral vector delivery that opens the opportunity for biological modification of the allograft prior to implantation that may improve post-transplant outcomes.
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Affiliation(s)
- Muath Bishawi
- Division of Cardiothoracic Surgery, Department of Surgery, Duke University, Durham, NC, USA.,Department of Biomedical Engineering, Pratt School of Engineering, Duke University, Durham, NC, USA
| | - Jun-Neng Roan
- Division of Cardiothoracic Surgery, Department of Surgery, Duke University, Durham, NC, USA.,Division of Cardiovascular Surgery, Department of Surgery, College of Medicine, National Cheng Kung University Hospital, Tainan City, Taiwan
| | - Carmelo A Milano
- Division of Cardiothoracic Surgery, Department of Surgery, Duke University, Durham, NC, USA
| | - Mani A Daneshmand
- Division of Cardiothoracic Surgery, Department of Surgery, Duke University, Durham, NC, USA
| | - Jacob N Schroder
- Division of Cardiothoracic Surgery, Department of Surgery, Duke University, Durham, NC, USA
| | - Yuting Chiang
- Division of Cardiothoracic Surgery, Department of Surgery, Duke University, Durham, NC, USA
| | - Franklin H Lee
- Division of Cardiothoracic Surgery, Department of Surgery, Duke University, Durham, NC, USA
| | - Zachary D Brown
- Division of Cardiothoracic Surgery, Department of Surgery, Duke University, Durham, NC, USA
| | - Adam Nevo
- Division of Cardiothoracic Surgery, Department of Surgery, Duke University, Durham, NC, USA
| | - Michael J Watson
- Division of Cardiothoracic Surgery, Department of Surgery, Duke University, Durham, NC, USA
| | | | - Sally Paul
- Perfusion Services, Duke University, Durham, NC, USA
| | | | | | - Dawn E Bowles
- Division of Surgical Sciences, Department of Surgery, Duke University, Durham, NC, USA.
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11
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Lee CH, Laurence DW, Ross CJ, Kramer KE, Babu AR, Johnson EL, Hsu MC, Aggarwal A, Mir A, Burkhart HM, Towner RA, Baumwart R, Wu Y. Mechanics of the Tricuspid Valve-From Clinical Diagnosis/Treatment, In-Vivo and In-Vitro Investigations, to Patient-Specific Biomechanical Modeling. Bioengineering (Basel) 2019; 6:E47. [PMID: 31121881 PMCID: PMC6630695 DOI: 10.3390/bioengineering6020047] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2019] [Revised: 05/16/2019] [Accepted: 05/17/2019] [Indexed: 12/29/2022] Open
Abstract
Proper tricuspid valve (TV) function is essential to unidirectional blood flow through the right side of the heart. Alterations to the tricuspid valvular components, such as the TV annulus, may lead to functional tricuspid regurgitation (FTR), where the valve is unable to prevent undesired backflow of blood from the right ventricle into the right atrium during systole. Various treatment options are currently available for FTR; however, research for the tricuspid heart valve, functional tricuspid regurgitation, and the relevant treatment methodologies are limited due to the pervasive expectation among cardiac surgeons and cardiologists that FTR will naturally regress after repair of left-sided heart valve lesions. Recent studies have focused on (i) understanding the function of the TV and the initiation or progression of FTR using both in-vivo and in-vitro methods, (ii) quantifying the biomechanical properties of the tricuspid valve apparatus as well as its surrounding heart tissue, and (iii) performing computational modeling of the TV to provide new insight into its biomechanical and physiological function. This review paper focuses on these advances and summarizes recent research relevant to the TV within the scope of FTR. Moreover, this review also provides future perspectives and extensions critical to enhancing the current understanding of the functioning and remodeling tricuspid valve in both the healthy and pathophysiological states.
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Affiliation(s)
- Chung-Hao Lee
- Biomechanics and Biomaterials Design Laboratory, School of Aerospace and Mechanical Engineering, The University of Oklahoma, Norman, OK 73019, USA.
- Institute for Biomedical Engineering, Science and Technology (IBEST), The University of Oklahoma, Norman, OK 73019, USA.
| | - Devin W Laurence
- Biomechanics and Biomaterials Design Laboratory, School of Aerospace and Mechanical Engineering, The University of Oklahoma, Norman, OK 73019, USA.
| | - Colton J Ross
- Biomechanics and Biomaterials Design Laboratory, School of Aerospace and Mechanical Engineering, The University of Oklahoma, Norman, OK 73019, USA.
| | - Katherine E Kramer
- Biomechanics and Biomaterials Design Laboratory, School of Aerospace and Mechanical Engineering, The University of Oklahoma, Norman, OK 73019, USA.
| | - Anju R Babu
- Biomechanics and Biomaterials Design Laboratory, School of Aerospace and Mechanical Engineering, The University of Oklahoma, Norman, OK 73019, USA.
- Department of Biotechnology and Medical Engineering, National Institute of Technology Rourkela, Rourkela, Odisha 769008, India.
| | - Emily L Johnson
- Department of Mechanical Engineering, Iowa State University, Ames, IA 50011, USA.
| | - Ming-Chen Hsu
- Department of Mechanical Engineering, Iowa State University, Ames, IA 50011, USA.
| | - Ankush Aggarwal
- Glasgow Computational Engineering Centre, School of Engineering, University of Glasgow, Scotland G12 8LT, UK.
| | - Arshid Mir
- Division of Pediatric Cardiology, Department of Pediatrics, The University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA.
| | - Harold M Burkhart
- Division of Cardiothoracic Surgery, Department of Surgery, The University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA.
| | - Rheal A Towner
- Advance Magnetic Resonance Center, MS 60, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, USA.
| | - Ryan Baumwart
- Center for Veterinary Health Sciences, Oklahoma State University, Stillwater, OK 74078, USA.
| | - Yi Wu
- Biomechanics and Biomaterials Design Laboratory, School of Aerospace and Mechanical Engineering, The University of Oklahoma, Norman, OK 73019, USA.
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12
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Lin HCA, Déan-Ben XL, Reiss M, Schöttle V, Wahl-Schott CA, Efimov IR, Razansky D. Ultrafast Volumetric Optoacoustic Imaging of Whole Isolated Beating Mouse Heart. Sci Rep 2018; 8:14132. [PMID: 30237560 PMCID: PMC6148063 DOI: 10.1038/s41598-018-32317-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Accepted: 09/03/2018] [Indexed: 01/22/2023] Open
Abstract
The Langendorff-perfused heart technique has become the model of choice for multiparametric optical mapping of cardiac function and electrophysiology. However, photon scattering in tissues represents a significant drawback of the optical imaging approach, fundamentally limiting its mapping capacity to the heart surface. This work presents the first implementation of the optoacoustic approach for 4D imaging of the entire beating isolated mouse heart. The method combines optical excitation and acoustic detection to simultaneously render rich optical contrast and high spatio-temporal resolution at centimeter-scale depths. We demonstrate volumetric imaging of deeply located cardiac features, including the interventricular septum, chordae tendineae, and papillary muscles while further tracking the heart beat cycle and the motion of the pulmonary, mitral, and tricuspid valves in real time. The technique possesses a powerful combination between high imaging depth, fast volumetric imaging speed, functional and molecular imaging capacities not available with other imaging modalities currently used in cardiac research.
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Affiliation(s)
- Hsiao-Chun Amy Lin
- Institute for Biological and Medical Imaging (IBMI), Helmholtz Center Munich, Neuherberg, Germany.,Faculty of Medicine, Technical University of Munich, Munich, Germany
| | - Xosé Luís Déan-Ben
- Institute for Biological and Medical Imaging (IBMI), Helmholtz Center Munich, Neuherberg, Germany
| | - Michael Reiss
- Institute for Biological and Medical Imaging (IBMI), Helmholtz Center Munich, Neuherberg, Germany.,Faculty of Medicine, Technical University of Munich, Munich, Germany
| | - Verena Schöttle
- Center for Integrated Protein Science and Center for Drug Research, Department of Pharmacy, Ludwig Maximilians University of Munich, Munich, Germany
| | - Christian A Wahl-Schott
- Center for Integrated Protein Science and Center for Drug Research, Department of Pharmacy, Ludwig Maximilians University of Munich, Munich, Germany
| | - Igor R Efimov
- Department of Biomedical Engineering, George Washington University, Washington, DC 20052, USA
| | - Daniel Razansky
- Institute for Biological and Medical Imaging (IBMI), Helmholtz Center Munich, Neuherberg, Germany. .,Faculty of Medicine, Technical University of Munich, Munich, Germany.
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13
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Bao J, Ye C, Zheng Z, Zhou Z. Fmr1 protects cardiomyocytes against lipopolysaccharide-induced myocardial injury. Exp Ther Med 2018; 16:1825-1833. [PMID: 30186407 PMCID: PMC6122302 DOI: 10.3892/etm.2018.6386] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Accepted: 02/16/2018] [Indexed: 12/22/2022] Open
Abstract
The present study explored the mechanisms by which fragile X mental retardation 1 (fmr1) overexpression inhibits lipopolysaccharide (LPS)-induced cardiomyocyte injury. Factors including oxidative stress reaction, mitochondrial membrane potential variation and cell apoptosis were evaluated. The viability of H9c2 cells was evaluated with a Cell Counting Kit-8 assay after cells were treated with LPS at different concentrations (0, 1, 3, 6 and 9 µg/ml) for various durations (4, 12 and 24 h). Flow cytometry was used to determine variations in reactive oxygen species (ROS), mitochondrial membrane potential and cell apoptosis. Reverse transcription-quantitative polymerase chain reaction and western blot analysis were performed to detect the levels of apoptosis-associated factors, and western blot analysis was used to determine the phosphorylation levels of phosphoinositide-3 kinase (PI3K), Akt and forkhead box (Fox)O3a. The results indicated that LPS decreased the viability of H9c2 cells in a dose- and time-dependent manner. Overexpression of fmr1 inhibited the LPS-induced decrease in the mitochondrial membrane potential and the production of ROS as well as apoptosis in H9c2 cells. Fmr1 also inhibited LPS-induced reductions in antioxidant enzyme activities, including those of superoxide dismutase and reduced/oxidized glutathione ratio, and decreased LPS-associated increases in the lipid peroxidation product malondialdehyde. Apoptosis-associated factors were identified to be involved in the effects of Fmr1. Overexpression of Fmr1 attenuated LPS-associated increases in the apoptosis-activating factors B-cell lymphoma 2 (Bcl-2)-associated X protein and caspase-3 and decreases in apoptosis inhibitors, including Bcl-2 and X-linked inhibitor of apoptosis protein. Fmr1 overexpression also reduced LPS-induced increases in the phosphorylation levels of PI3K, Akt and FoxO3a. In conclusion, fmr1 overexpression alleviated oxidative stress and apoptosis in H9c2 cardiomyocytes injured by LPS via regulating oxidative stress and apoptosis-associated factors, as well as the PI3K/Akt pathway. This information may provide a novel and effective therapeutic strategy for heart diseases.
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Affiliation(s)
- Jiasheng Bao
- Department of Electrocardiogram Diagnosis, Zhejiang Hospital, Hangzhou, Zhejiang 310013, P.R. China
| | - Chen Ye
- Department of Cardiovascular Medicine, Zhejiang Hospital, Hangzhou, Zhejiang 310013, P.R. China
| | - Zhelan Zheng
- Department of Cardiovascular Ultrasonic Center, The First Affiliated Hospital of Zhejiang University, The First Hospital of Zhejiang Province, Hangzhou, Zhejiang 310003, P.R. China
| | - Zhengwen Zhou
- Department of Electrocardiogram Diagnosis, Zhejiang Hospital, Hangzhou, Zhejiang 310013, P.R. China
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14
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Jungen C, Scherschel K, Bork NI, Kuklik P, Eickholt C, Kniep H, Klatt N, Willems S, Nikolaev VO, Meyer C. Impact of Intracardiac Neurons on Cardiac Electrophysiology and Arrhythmogenesis in an Ex Vivo Langendorff System. J Vis Exp 2018. [PMID: 29889210 DOI: 10.3791/57617] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Since its invention in the late 19th century, the Langendorff ex vivo heart perfusion system continues to be a relevant tool for studying a broad spectrum of physiological, biochemical, morphological, and pharmacological parameters in centrally denervated hearts. Here, we describe a setup for the modulation of the intracardiac autonomic nervous system and the assessment of its influence on basic electrophysiology, arrhythmogenesis, and cyclic adenosine monophosphate (cAMP) dynamics. The intracardiac autonomic nervous system is modulated by the mechanical dissection of atrial fat pads-in which murine ganglia are located mainly-or by the usage of global as well as targeted pharmacological interventions. An octapolar electrophysiological catheter is introduced into the right atrium and the right ventricle, and epicardial-placed multi-electrode arrays (MEA) for high-resolution mapping are used to determine cardiac electrophysiology and arrhythmogenesis. Förster resonance energy transfer (FRET) imaging is performed for the real-time monitoring of cAMP levels in different cardiac regions. Neuromorphology is studied by means of antibody-based staining of whole hearts using neuronal markers to guide the identification and modulation of specific targets of the intracardiac autonomic nervous system in the performed studies. The ex vivo Langendorff setup allows for a high number of reproducible experiments in a short time. Nevertheless, the partly open nature of the setup (e.g., during MEA measurements) makes constant temperature control difficult and should be kept to a minimum. This described method makes it possible to analyze and modulate the intracardiac autonomic nervous system in decentralized hearts.
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Affiliation(s)
- Christiane Jungen
- Department of Cardiology-Electrophysiology, cNEP (cardiac Neuro- and Electrophysiology research group), University Heart Center, University Hospital Hamburg-Eppendorf; DZHK (German Center for Cardiovascular Research)
| | - Katharina Scherschel
- Department of Cardiology-Electrophysiology, cNEP (cardiac Neuro- and Electrophysiology research group), University Heart Center, University Hospital Hamburg-Eppendorf; DZHK (German Center for Cardiovascular Research)
| | - Nadja I Bork
- DZHK (German Center for Cardiovascular Research); Institute of Experimental Cardiovascular Research, University Medical Center Hamburg-Eppendorf
| | - Pawel Kuklik
- Department of Cardiology-Electrophysiology, cNEP (cardiac Neuro- and Electrophysiology research group), University Heart Center, University Hospital Hamburg-Eppendorf
| | - Christian Eickholt
- Department of Cardiology-Electrophysiology, cNEP (cardiac Neuro- and Electrophysiology research group), University Heart Center, University Hospital Hamburg-Eppendorf
| | - Helge Kniep
- Department of Cardiology-Electrophysiology, cNEP (cardiac Neuro- and Electrophysiology research group), University Heart Center, University Hospital Hamburg-Eppendorf
| | - Niklas Klatt
- Department of Cardiology-Electrophysiology, cNEP (cardiac Neuro- and Electrophysiology research group), University Heart Center, University Hospital Hamburg-Eppendorf; DZHK (German Center for Cardiovascular Research)
| | - Stephan Willems
- Department of Cardiology-Electrophysiology, cNEP (cardiac Neuro- and Electrophysiology research group), University Heart Center, University Hospital Hamburg-Eppendorf; DZHK (German Center for Cardiovascular Research)
| | - Viacheslav O Nikolaev
- DZHK (German Center for Cardiovascular Research); Institute of Experimental Cardiovascular Research, University Medical Center Hamburg-Eppendorf
| | - Christian Meyer
- Department of Cardiology-Electrophysiology, cNEP (cardiac Neuro- and Electrophysiology research group), University Heart Center, University Hospital Hamburg-Eppendorf; DZHK (German Center for Cardiovascular Research);
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