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Cavallero S, Roustaei M, Satta S, Cho JM, Phan H, Baek KI, Blázquez-Medela AM, Gonzalez-Ramos S, Vu K, Park SK, Yokota T, Sumner J, Mack JJ, Sigmund CD, Reddy ST, Li R, Hsiai TK. Exercise mitigates flow recirculation and activates metabolic transducer SCD1 to catalyze vascular protective metabolites. SCIENCE ADVANCES 2024; 10:eadj7481. [PMID: 38354249 PMCID: PMC10866565 DOI: 10.1126/sciadv.adj7481] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Accepted: 01/11/2024] [Indexed: 02/16/2024]
Abstract
Exercise promotes pulsatile shear stress in the arterial circulation and ameliorates cardiometabolic diseases. However, exercise-mediated metabolic transducers for vascular protection remain under-investigated. Untargeted metabolomic analysis demonstrated that wild-type mice undergoing voluntary wheel running exercise expressed increased endothelial stearoyl-CoA desaturase 1 (SCD1) that catalyzes anti-inflammatory lipid metabolites, namely, oleic (OA) and palmitoleic acids (PA), to mitigate NF-κB-mediated inflammatory responses. In silico analysis revealed that exercise augmented time-averaged wall shear stress but mitigated flow recirculation and oscillatory shear index in the lesser curvature of the mouse aortic arch. Following exercise, endothelial Scd1-deleted mice (Ldlr-/- Scd1EC-/-) on high-fat diet developed persistent VCAM1-positive endothelium in the lesser curvature and the descending aorta, whereas SCD1 overexpression via adenovirus transfection mitigated endoplasmic reticulum stress and inflammatory biomarkers. Single-cell transcriptomics of the aorta identified Scd1-positive and Vcam1-negative endothelial subclusters interacting with other candidate genes. Thus, exercise mitigates flow recirculation and activates endothelial SCD1 to catalyze OA and PA for vascular endothelial protection.
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Affiliation(s)
- Susana Cavallero
- Division of Cardiology, Department of Medicine, David Geffen School of Medicine at University of California, Los Angeles, CA, USA
- Department of Medicine, VA Greater Los Angeles Health Care System, Los Angeles, CA, USA
| | - Mehrdad Roustaei
- Department of Bioengineering, School of Engineering and Applied Science, University of California, Los Angeles, CA, USA
| | - Sandro Satta
- Division of Cardiology, Department of Medicine, David Geffen School of Medicine at University of California, Los Angeles, CA, USA
- Department of Medicine, VA Greater Los Angeles Health Care System, Los Angeles, CA, USA
| | - Jae Min Cho
- Division of Cardiology, Department of Medicine, David Geffen School of Medicine at University of California, Los Angeles, CA, USA
- Department of Medicine, VA Greater Los Angeles Health Care System, Los Angeles, CA, USA
| | - Henry Phan
- Division of Cardiology, Department of Medicine, David Geffen School of Medicine at University of California, Los Angeles, CA, USA
| | - Kyung In Baek
- Department of Bioengineering, School of Engineering and Applied Science, University of California, Los Angeles, CA, USA
| | - Ana M. Blázquez-Medela
- Division of Cardiology, Department of Medicine, David Geffen School of Medicine at University of California, Los Angeles, CA, USA
- Department of Medicine, VA Greater Los Angeles Health Care System, Los Angeles, CA, USA
| | - Sheila Gonzalez-Ramos
- Department of Bioengineering, School of Engineering and Applied Science, University of California, Los Angeles, CA, USA
| | - Khoa Vu
- Department of Bioengineering, School of Engineering and Applied Science, University of California, Los Angeles, CA, USA
| | - Seul-Ki Park
- Division of Cardiology, Department of Medicine, David Geffen School of Medicine at University of California, Los Angeles, CA, USA
| | - Tomohiro Yokota
- Division of Cardiology, Department of Medicine, David Geffen School of Medicine at University of California, Los Angeles, CA, USA
- Department of Medicine, VA Greater Los Angeles Health Care System, Los Angeles, CA, USA
| | - Jennifer Sumner
- Department of Psychology, College of Life Sciences, University of California, Los Angeles, CA, USA
| | - Julia J. Mack
- Division of Cardiology, Department of Medicine, David Geffen School of Medicine at University of California, Los Angeles, CA, USA
| | - Curt D. Sigmund
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Srinivasa T. Reddy
- Division of Cardiology, Department of Medicine, David Geffen School of Medicine at University of California, Los Angeles, CA, USA
- Department of Molecular and Medical Pharmacology, University of California, Los Angeles, CA, USA
| | - Rongsong Li
- Division of Cardiology, Department of Medicine, David Geffen School of Medicine at University of California, Los Angeles, CA, USA
- Department of Medicine, VA Greater Los Angeles Health Care System, Los Angeles, CA, USA
| | - Tzung K. Hsiai
- Division of Cardiology, Department of Medicine, David Geffen School of Medicine at University of California, Los Angeles, CA, USA
- Department of Medicine, VA Greater Los Angeles Health Care System, Los Angeles, CA, USA
- Department of Bioengineering, School of Engineering and Applied Science, University of California, Los Angeles, CA, USA
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Cavallero S, Roustaei M, Satta S, Cho JM, Phan H, Baek KI, Blázquez-Medela AM, Gonzalez-Ramos S, Vu K, Park SK, Yokota T, Sumner JA, Mack JJ, Sigmund CD, Reddy ST, Li R, Hsiai TK. Exercise Mitigates Flow Recirculation and Activates Mechanosensitive Transcriptome to Uncover Endothelial SCD1-Catalyzed Anti-Inflammatory Metabolites. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.02.539172. [PMID: 37205360 PMCID: PMC10187200 DOI: 10.1101/2023.05.02.539172] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Exercise modulates vascular plasticity in multiple organ systems; however, the metabolomic transducers underlying exercise and vascular protection in the disturbed flow-prone vasculature remain under-investigated. We simulated exercise-augmented pulsatile shear stress (PSS) to mitigate flow recirculation in the lesser curvature of the aortic arch. When human aortic endothelial cells (HAECs) were subjected to PSS ( τ ave = 50 dyne·cm -2 , ∂τ/∂t = 71 dyne·cm -2 ·s -1 , 1 Hz), untargeted metabolomic analysis revealed that Stearoyl-CoA Desaturase (SCD1) in the endoplasmic reticulum (ER) catalyzed the fatty acid metabolite, oleic acid (OA), to mitigate inflammatory mediators. Following 24 hours of exercise, wild-type C57BL/6J mice developed elevated SCD1-catalyzed lipid metabolites in the plasma, including OA and palmitoleic acid (PA). Exercise over a 2-week period increased endothelial SCD1 in the ER. Exercise further modulated the time-averaged wall shear stress (TAWSS or τ ave) and oscillatory shear index (OSI ave ), upregulated Scd1 and attenuated VCAM1 expression in the disturbed flow-prone aortic arch in Ldlr -/- mice on high-fat diet but not in Ldlr -/- Scd1 EC-/- mice. Scd1 overexpression via recombinant adenovirus also mitigated ER stress. Single cell transcriptomic analysis of the mouse aorta revealed interconnection of Scd1 with mechanosensitive genes, namely Irs2 , Acox1 and Adipor2 that modulate lipid metabolism pathways. Taken together, exercise modulates PSS ( τ ave and OSI ave ) to activate SCD1 as a metabolomic transducer to ameliorate inflammation in the disturbed flow-prone vasculature.
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Integrated cardio-behavioral responses to threat define defensive states. Nat Neurosci 2023; 26:447-457. [PMID: 36759559 PMCID: PMC9991919 DOI: 10.1038/s41593-022-01252-w] [Citation(s) in RCA: 18] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Accepted: 12/21/2022] [Indexed: 02/11/2023]
Abstract
Fear and anxiety are brain states that evolved to mediate defensive responses to threats. The defense reaction includes multiple interacting behavioral, autonomic and endocrine adjustments, but their integrative nature is poorly understood. In particular, although threat has been associated with various cardiac changes, there is no clear consensus regarding the relevance of these changes for the integrated defense reaction. Here we identify rapid microstates that are associated with specific behaviors and heart rate dynamics, which are affected by long-lasting macrostates and reflect context-dependent threat levels. In addition, we demonstrate that one of the most commonly used defensive behavioral responses-freezing as measured by immobility-is part of an integrated cardio-behavioral microstate mediated by Chx10+ neurons in the periaqueductal gray. Our framework for systematic integration of cardiac and behavioral readouts presents the basis for a better understanding of complex neural defensive states and their associated systemic functions.
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Fan L, Sun Y, Choy JS, Kassab GS, Lee LC. Mechanism of exercise intolerance in heart diseases predicted by a computer model of myocardial demand-supply feedback system. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2022; 227:107188. [PMID: 36334525 DOI: 10.1016/j.cmpb.2022.107188] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Revised: 09/28/2022] [Accepted: 10/16/2022] [Indexed: 06/16/2023]
Abstract
BACKGROUND AND OBJECTIVE The myocardial demand-supply feedback system plays an important role in augmenting blood supply in response to exercise-induced increased myocardial demand. During this feedback process, the myocardium and coronary blood flow interact bidirectionally at many different levels. METHODS To investigate these interactions, a novel computational framework that considers the closed myocardial demand-supply feedback system was developed. In the framework coupling the systemic circulation of the left ventricle and coronary perfusion with regulation, myocardial work affects coronary perfusion via flow regulation mechanisms (e.g., metabolic regulation) and myocardial-vessel interactions, whereas coronary perfusion affects myocardial contractility in a closed feedback system. The framework was calibrated based on the measurements from healthy subjects under graded exercise conditions, and then was applied to simulate the effects of graded exercise on myocardial demand-supply under different physiological and pathological conditions. RESULTS We found that the framework can recapitulate key features found during exercise in clinical and animal studies. We showed that myocardial blood flow is increased but maximum hyperemia is reduced during exercise, which led to a reduction in coronary flow reserve. For coronary stenosis and myocardial inefficiency, the model predicts that an increase in heart rate is necessary to maintain the baseline cardiac output. Correspondingly, the resting coronary flow reserve is exhausted and the range of heart rate before exhaustion of coronary flow reserve is reduced. In the presence of metabolic regulation dysfunction, the model predicts that the metabolic vasodilator signal is higher at rest, saturates faster during exercise, and as a result, causes quicker exhaustion of coronary flow reserve. CONCLUSIONS Model predictions showed that the coronary flow reserve deteriorates faster during graded exercise, which in turn, suggests a decrease in exercise tolerance for patients with stenosis, myocardial inefficiency and metabolic flow regulation dysfunction. The findings in this study may have clinical implications in diagnosing cardiovascular diseases.
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Affiliation(s)
- Lei Fan
- Department of Mechanical Engineering, Michigan State University, East Lansing, MI, USA.
| | - Yuexing Sun
- Department of Mechanical Engineering, Michigan State University, East Lansing, MI, USA
| | - Jenny S Choy
- California Medical Innovations Institute, San Diego, CA, USA
| | | | - Lik Chuan Lee
- Department of Mechanical Engineering, Michigan State University, East Lansing, MI, USA
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Hastings MH, Herrera JJ, Guseh JS, Atlason B, Houstis NE, Abdul Kadir A, Li H, Sheffield C, Singh AP, Roh JD, Day SM, Rosenzweig A. Animal Models of Exercise From Rodents to Pythons. Circ Res 2022; 130:1994-2014. [PMID: 35679366 PMCID: PMC9202075 DOI: 10.1161/circresaha.122.320247] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Acute and chronic animal models of exercise are commonly used in research. Acute exercise testing is used, often in combination with genetic, pharmacological, or other manipulations, to study the impact of these manipulations on the cardiovascular response to exercise and to detect impairments or improvements in cardiovascular function that may not be evident at rest. Chronic exercise conditioning models are used to study the cardiac phenotypic response to regular exercise training and as a platform for discovery of novel pathways mediating cardiovascular benefits conferred by exercise conditioning that could be exploited therapeutically. The cardiovascular benefits of exercise are well established, and, frequently, molecular manipulations that mimic the pathway changes induced by exercise recapitulate at least some of its benefits. This review discusses approaches for assessing cardiovascular function during an acute exercise challenge in rodents, as well as practical and conceptual considerations in the use of common rodent exercise conditioning models. The case for studying feeding in the Burmese python as a model for exercise-like physiological adaptation is also explored.
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Affiliation(s)
- Margaret H Hastings
- Department of Medicine, Division of Cardiology, Cardiovascular Research Center, Corrigan Minehan Heart Center, Massachusetts General Hospital, Harvard Medical School, Boston (M.H.H., J.S.G., B.A., N.E.H., A.A.K., H.L., C.S., A.P.S., J.D.R., A.R.)
| | - Jonathan J Herrera
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor (J.J.H.)
| | - J Sawalla Guseh
- Department of Medicine, Division of Cardiology, Cardiovascular Research Center, Corrigan Minehan Heart Center, Massachusetts General Hospital, Harvard Medical School, Boston (M.H.H., J.S.G., B.A., N.E.H., A.A.K., H.L., C.S., A.P.S., J.D.R., A.R.)
| | - Bjarni Atlason
- Department of Medicine, Division of Cardiology, Cardiovascular Research Center, Corrigan Minehan Heart Center, Massachusetts General Hospital, Harvard Medical School, Boston (M.H.H., J.S.G., B.A., N.E.H., A.A.K., H.L., C.S., A.P.S., J.D.R., A.R.)
| | - Nicholas E Houstis
- Department of Medicine, Division of Cardiology, Cardiovascular Research Center, Corrigan Minehan Heart Center, Massachusetts General Hospital, Harvard Medical School, Boston (M.H.H., J.S.G., B.A., N.E.H., A.A.K., H.L., C.S., A.P.S., J.D.R., A.R.)
| | - Azrul Abdul Kadir
- Department of Medicine, Division of Cardiology, Cardiovascular Research Center, Corrigan Minehan Heart Center, Massachusetts General Hospital, Harvard Medical School, Boston (M.H.H., J.S.G., B.A., N.E.H., A.A.K., H.L., C.S., A.P.S., J.D.R., A.R.)
| | - Haobo Li
- Department of Medicine, Division of Cardiology, Cardiovascular Research Center, Corrigan Minehan Heart Center, Massachusetts General Hospital, Harvard Medical School, Boston (M.H.H., J.S.G., B.A., N.E.H., A.A.K., H.L., C.S., A.P.S., J.D.R., A.R.)
| | - Cedric Sheffield
- Department of Medicine, Division of Cardiology, Cardiovascular Research Center, Corrigan Minehan Heart Center, Massachusetts General Hospital, Harvard Medical School, Boston (M.H.H., J.S.G., B.A., N.E.H., A.A.K., H.L., C.S., A.P.S., J.D.R., A.R.)
| | - Anand P Singh
- Department of Medicine, Division of Cardiology, Cardiovascular Research Center, Corrigan Minehan Heart Center, Massachusetts General Hospital, Harvard Medical School, Boston (M.H.H., J.S.G., B.A., N.E.H., A.A.K., H.L., C.S., A.P.S., J.D.R., A.R.)
| | - Jason D Roh
- Department of Medicine, Division of Cardiology, Cardiovascular Research Center, Corrigan Minehan Heart Center, Massachusetts General Hospital, Harvard Medical School, Boston (M.H.H., J.S.G., B.A., N.E.H., A.A.K., H.L., C.S., A.P.S., J.D.R., A.R.)
| | - Sharlene M Day
- Cardiovascular Medicine, Perelman School of Medicine' University of Pennsylvania, Philadelphia (S.M.D.)
| | - Anthony Rosenzweig
- Department of Medicine, Division of Cardiology, Cardiovascular Research Center, Corrigan Minehan Heart Center, Massachusetts General Hospital, Harvard Medical School, Boston (M.H.H., J.S.G., B.A., N.E.H., A.A.K., H.L., C.S., A.P.S., J.D.R., A.R.)
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6
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Roh J, Hill JA, Singh A, Valero-Muñoz M, Sam F. Heart Failure With Preserved Ejection Fraction: Heterogeneous Syndrome, Diverse Preclinical Models. Circ Res 2022; 130:1906-1925. [PMID: 35679364 PMCID: PMC10035274 DOI: 10.1161/circresaha.122.320257] [Citation(s) in RCA: 45] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Heart failure with preserved ejection fraction (HFpEF) represents one of the greatest challenges facing cardiovascular medicine today. Despite being the most common form of heart failure worldwide, there has been limited success in developing therapeutics for this syndrome. This is largely due to our incomplete understanding of the biology driving its systemic pathophysiology and the heterogeneity of clinical phenotypes, which are increasingly being recognized as distinct HFpEF phenogroups. Development of efficacious therapeutics fundamentally relies on robust preclinical models that not only faithfully recapitulate key features of the clinical syndrome but also enable rigorous investigation of putative mechanisms of disease in the context of clinically relevant phenotypes. In this review, we propose a preclinical research strategy that is conceptually grounded in model diversification and aims to better align with our evolving understanding of the heterogeneity of clinical HFpEF. Although heterogeneity is often viewed as a major obstacle in preclinical HFpEF research, we challenge this notion and argue that embracing it may be the key to demystifying its pathobiology. Here, we first provide an overarching guideline for developing HFpEF models through a stepwise approach of comprehensive cardiac and extra-cardiac phenotyping. We then present an overview of currently available models, focused on the 3 leading phenogroups, which are primarily based on aging, cardiometabolic stress, and chronic hypertension. We discuss how well these models reflect their clinically relevant phenogroup and highlight some of the more recent mechanistic insights they are providing into the complex pathophysiology underlying HFpEF.
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Affiliation(s)
- Jason Roh
- Cardiovascular Research Center, Massachusetts General Hospital, Boston (J.R., A.S.)
| | - Joseph A Hill
- Department of Internal Medicine (Cardiology) (J.A.H.), University of Texas Southwestern Medical Center, Dallas
- Department of Molecular Biology (J.A.H.), University of Texas Southwestern Medical Center, Dallas
| | - Abhilasha Singh
- Cardiovascular Research Center, Massachusetts General Hospital, Boston (J.R., A.S.)
| | - María Valero-Muñoz
- Whitaker Cardiovascular Institute, Boston University School of Medicine, MA (M.V.-M., F.S.)
| | - Flora Sam
- Whitaker Cardiovascular Institute, Boston University School of Medicine, MA (M.V.-M., F.S.)
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7
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Cardiac myocyte intrinsic contractility and calcium handling deficits underlie heart organ dysfunction in murine cancer cachexia. Sci Rep 2021; 11:23627. [PMID: 34880268 PMCID: PMC8655071 DOI: 10.1038/s41598-021-02688-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Accepted: 11/02/2021] [Indexed: 12/11/2022] Open
Abstract
Cachexia is a muscle wasting syndrome occurring in many advanced cancer patients. Cachexia significantly increases cancer morbidity and mortality. Cardiac atrophy and contractility deficits have been observed in patients and in animal models with cancer cachexia, which may contribute to cachexia pathophysiology. However, underlying contributors to decreased in vivo cardiac contractility are not well understood. In this study, we sought to distinguish heart-intrinsic changes from systemic factors contributing to cachexia-associated cardiac dysfunction. We hypothesized that isolated heart and cardiac myocyte functional deficits underlie in vivo contractile dysfunction. To test this hypothesis, isolated heart and cardiac myocyte function was measured in the colon-26 adenocarcinoma murine model of cachexia. Ex vivo perfused hearts from cachectic animals exhibited marked contraction and relaxation deficits during basal and pacing conditions. Isolated myocytes displayed significantly decreased peak contraction and relaxation rates, which was accompanied by decreased peak calcium and decay rates. This study uncovers significant organ and cellular-level functional deficits in cachectic hearts outside of the catabolic in vivo environment, which is explained in part by impaired calcium cycling. These data provide insight into physiological mechanisms of cardiomyopathy in cachexia, which is critical for the ultimate development of effective treatments for patients.
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8
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Barazi N, Polidovitch N, Debi R, Yakobov S, Lakin R, Backx PH. Dissecting the Roles of the Autonomic Nervous System and Physical Activity on Circadian Heart Rate Fluctuations in Mice. Front Physiol 2021; 12:692247. [PMID: 34733171 PMCID: PMC8558381 DOI: 10.3389/fphys.2021.692247] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Accepted: 09/22/2021] [Indexed: 01/02/2023] Open
Abstract
Heart rate (HR) and blood pressure as well as adverse cardiovascular events show clear circadian patterns, which are linked to interdependent daily variations in physical activity and cardiac autonomic nerve system (ANS) activity. We set out to assess the relative contributions of the ANS (alone) and physical activity to circadian HR fluctuations. To do so, we measured HR (beats per minute, bpm) in mice that were either immobilized using isoflurane anesthesia or free-moving. Nonlinear fits of HR data to sine functions revealed that anesthetized mice display brisk circadian HR fluctuations with amplitudes of 47.1±7.4bpm with the highest HRs in middle of the dark (active) period (ZT 18: 589±46bpm) and lowest HRs in the middle of the light (rest) period (ZT 6: 497±54bpm). The circadian HR fluctuations were reduced by ~70% following blockade of cardiac parasympathetic nervous activity (PNA) with atropine while declining by <15% following cardiac sympathetic nerve activity (SNA) blockade with propranolol. Small HR fluctuation amplitudes (11.6±5.9bpm) remained after complete cardiac ANS blockade. Remarkably, circadian HR fluctuation amplitudes in freely moving, telemetrized mice were only ~32% larger than in anesthetized mice. However, after gaining access to running wheels for 1week, circadian HR fluctuations increase to 102.9±12.1bpm and this is linked directly to increased O2 consumption during running. We conclude that, independent of physical activity, the ANS is a major determinant of circadian HR variations with PNA playing a dominant role compared to SNA. The effects of physical activity to the daily HR variations are remarkably small unless mice get access to running wheels.
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Affiliation(s)
- Nour Barazi
- Department of Biology, York University, Toronto, ON, Canada
| | | | - Ryan Debi
- Department of Biology, York University, Toronto, ON, Canada
| | - Simona Yakobov
- Department of Biology, York University, Toronto, ON, Canada
| | - Robert Lakin
- Department of Biology, York University, Toronto, ON, Canada
| | - Peter H Backx
- Department of Biology, York University, Toronto, ON, Canada
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9
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Salem T, Frankman Z, Churko J. Tissue engineering techniques for iPSC derived three-dimensional cardiac constructs. TISSUE ENGINEERING PART B-REVIEWS 2021; 28:891-911. [PMID: 34476988 PMCID: PMC9419978 DOI: 10.1089/ten.teb.2021.0088] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Recent developments in applied developmental physiology have provided well-defined methodologies for producing human stem cell derived cardiomyocytes. Cardiomyocytes produced in this way have become commonplace as cardiac physiology research models. This accessibility has also allowed for the development of tissue engineered human heart constructs for drug screening, surgical intervention, and investigating cardiac pathogenesis. However, cardiac tissue engineering is an interdisciplinary field that involves complex engineering and physiological concepts, which limits its accessibility. This review provides a readable, broad reaching, and thorough discussion of major factors to consider for the development of cardiovascular tissues from stem cell derived cardiomyocytes. This review will examine important considerations in undertaking a cardiovascular tissue engineering project, and will present, interpret, and summarize some of the recent advancements in this field. This includes reviewing different forms of tissue engineered constructs, a discussion on cardiomyocyte sources, and an in-depth discussion of the fabrication and maturation procedures for tissue engineered heart constructs.
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Affiliation(s)
- Tori Salem
- University of Arizona Medical Center - University Campus, 22165, Cellular and Molecular Medicine, Tucson, Arizona, United States;
| | - Zachary Frankman
- University of Arizona Medical Center - University Campus, 22165, Biomedical Engineering, Tucson, Arizona, United States;
| | - Jared Churko
- University of Arizona Medical Center - University Campus, 22165, 1501 N Campbell RD, SHC 6143, Tucson, Arizona, United States, 85724-5128;
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10
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Fitzgerald BT, Logan JK, Weldon A, Kwon A, Scalia IG, Scalia GM. The prognostic value of estimating stroke volume before and after exercise during treadmill stress echocardiography. Echocardiography 2020; 37:1809-1819. [PMID: 32949039 DOI: 10.1111/echo.14863] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Revised: 08/21/2020] [Accepted: 08/29/2020] [Indexed: 11/27/2022] Open
Abstract
BACKGROUND Stress echocardiography (SE) is an established technique for assessment of coronary artery disease (CAD) which is difficult to perform and interpret. Left ventricular stroke volume (SV) is readily estimated with Doppler echocardiography. It can be affected by myocardial ischemia, with possible adjunctive value during SE. METHODS Patients underwent Bruce protocol SE with SV estimated before and after maximal treadmill exertion post routine regional wall analysis. Incremental change in SV (ΔSV) with exercise was measured. RESULTS A derivation cohort (n = 273) was established to test the hypothesis. An optimal cutoff for detection on inducible ischemia was ΔSV ≤ +10 mL. The validation cohort of consecutive patients (n = 1093, 376 [34%] female; age 59 ± 12 years) were followed clinically after SE for 20 460 patient-months. There were 1000 patients with nonischemic SE, and 93 patients with studies suggestive of myocardial ischemia. Secondary analysis yielded 831 patients with a normal exercise response (ΔSV > +10 mL) and 192 with an abnormal ΔSV ≤ +10 mL. Time to first combined adverse cardiac event (composite of angina, acute coronary syndrome, cardiac revascularization, worsening New York Heart Association (NYHA) class, a reduction in EF, and cardiovascular death) was analyzed and adjusted using Cox proportional hazards regression. The hazard ratio for an adverse event with an abnormal ΔSV response (≤10 mL) was 10.3 (95% confidence intervals 5.6-19.1, P < .0001). CONCLUSIONS Stroke volume assessment during SE is feasible and readily performed. It is simple, practical, and has incremental diagnostic and prognostic value when added to exercise regional wall-motion analysis.
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Affiliation(s)
- Benjamin T Fitzgerald
- GenesisCare Cardiology, Auchenflower, QLD, Australia.,The Wesley Hospital, Auchenflower, QLD, Australia.,The Prince Charles Hospital, Brisbane, QLD, Australia
| | - Jelena K Logan
- GenesisCare Cardiology, Auchenflower, QLD, Australia.,The Wesley Hospital, Auchenflower, QLD, Australia
| | - Ashleigh Weldon
- GenesisCare Cardiology, Auchenflower, QLD, Australia.,The Wesley Hospital, Auchenflower, QLD, Australia
| | - Agatha Kwon
- GenesisCare Cardiology, Auchenflower, QLD, Australia.,The Wesley Hospital, Auchenflower, QLD, Australia
| | | | - Gregory M Scalia
- GenesisCare Cardiology, Auchenflower, QLD, Australia.,The Wesley Hospital, Auchenflower, QLD, Australia.,The Prince Charles Hospital, Brisbane, QLD, Australia.,University of Queensland, Brisbane, QLD, Australia
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11
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Turco S, El Kaffas A, Zhou J, Lutz AM, Wijkstra H, Willmann JK, Mischi M. Pharmacokinetic Modeling of Targeted Ultrasound Contrast Agents for Quantitative Assessment of Anti-Angiogenic Therapy: a Longitudinal Case-Control Study in Colon Cancer. Mol Imaging Biol 2020; 21:633-643. [PMID: 30225758 PMCID: PMC6616210 DOI: 10.1007/s11307-018-1274-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
PURPOSE To evaluate quantitative and semi-quantitative ultrasound molecular imaging (USMI) for antiangiogenic therapy monitoring in human colon cancer xenografts in mice. PROCEDURES Colon cancer was established in 17 mice by injection of LS174T (Nr = 9) or CT26 (Nn = 8) cancer cells to simulate clinical responders and non-responders, respectively. Antiangiogenic treatment (bevacizumab; Nrt = Nnt = 5) or control treatment (saline; Nrc = 4, Nnc = 3) was administered at days 0, 3, and 7. Three-dimensional USMI was performed by injection at days 0, 1, 3, 7, and 10 of microbubbles targeted to the vascular endothelial growth factor receptor 2 (VEGFR2). Microbubble binding rate (kb), estimated by first-pass binding model fitting, and semi-quantitative parameters late enhancement (LE) and differential targeted enhancement (dTE) were compared at each day to evaluate their ability to assess and predict the response to therapy. Correlation analysis with the ex-vivo immunohistological quantification of VEGFR2 expression and the percentage blood vessel area was also performed. RESULTS Significant changes in the USMI parameters during treatment were observed only in the responders treated with bevacizumab (p-value < 0.05). Prediction of the response to therapy as early as 1 day after treatment was achieved by the quantitative parameter kb (p-value < 0.01), earlier than possible by tumor volume quantification. USMI parameters could significantly distinguish between clinical responders and non-responders (p-value << 0.01) and correlated well with the ex-vivo quantification of VEGFR2 expression and the percentage blood vessels area (p-value << 0.01). CONCLUSION USMI (semi)quantitative parameters provide earlier assessment of the response to therapy compared to tumor volume, permit early prediction of non-responders, and correlate well with ex-vivo angiogenesis biomarkers.
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Affiliation(s)
- Simona Turco
- Department of Electrical Engineering, Eindhoven University of Technology, Groene Loper 19, 5612 AZ, Eindhoven, The Netherlands.
| | - Ahmed El Kaffas
- Department of Radiology, Stanford Medicine, Stanford, CA, 94305, USA
| | - Jianhua Zhou
- Department of Ultrasound, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-Sen University Cancer Center, Guangzhou, China
| | - Amelie M Lutz
- Department of Radiology, Stanford Medicine, Stanford, CA, 94305, USA
| | - Hessel Wijkstra
- Department of Electrical Engineering, Eindhoven University of Technology, Groene Loper 19, 5612 AZ, Eindhoven, The Netherlands
- Department of Urology, Academic Medical Center, 1105 AZ, Amsterdam, The Netherlands
| | - Jürgen K Willmann
- Department of Radiology, Stanford Medicine, Stanford, CA, 94305, USA
| | - Massimo Mischi
- Department of Electrical Engineering, Eindhoven University of Technology, Groene Loper 19, 5612 AZ, Eindhoven, The Netherlands
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12
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Kupfer ME, Lin WH, Ravikumar V, Qiu K, Wang L, Gao L, Bhuiyan DB, Lenz M, Ai J, Mahutga RR, Townsend D, Zhang J, McAlpine MC, Tolkacheva EG, Ogle BM. In Situ Expansion, Differentiation, and Electromechanical Coupling of Human Cardiac Muscle in a 3D Bioprinted, Chambered Organoid. Circ Res 2020; 127:207-224. [PMID: 32228120 DOI: 10.1161/circresaha.119.316155] [Citation(s) in RCA: 152] [Impact Index Per Article: 38.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
RATIONALE One goal of cardiac tissue engineering is the generation of a living, human pump in vitro that could replace animal models and eventually serve as an in vivo therapeutic. Models that replicate the geometrically complex structure of the heart, harboring chambers and large vessels with soft biomaterials, can be achieved using 3-dimensional bioprinting. Yet, inclusion of contiguous, living muscle to support pump function has not been achieved. This is largely due to the challenge of attaining high densities of cardiomyocytes-a notoriously nonproliferative cell type. An alternative strategy is to print with human induced pluripotent stem cells, which can proliferate to high densities and fill tissue spaces, and subsequently differentiate them into cardiomyocytes in situ. OBJECTIVE To develop a bioink capable of promoting human induced pluripotent stem cell proliferation and cardiomyocyte differentiation to 3-dimensionally print electromechanically functional, chambered organoids composed of contiguous cardiac muscle. METHODS AND RESULTS We optimized a photo-crosslinkable formulation of native ECM (extracellular matrix) proteins and used this bioink to 3-dimensionally print human induced pluripotent stem cell-laden structures with 2 chambers and a vessel inlet and outlet. After human induced pluripotent stem cells proliferated to a sufficient density, we differentiated the cells within the structure and demonstrated function of the resultant human chambered muscle pump. Human chambered muscle pumps demonstrated macroscale beating and continuous action potential propagation with responsiveness to drugs and pacing. The connected chambers allowed for perfusion and enabled replication of pressure/volume relationships fundamental to the study of heart function and remodeling with health and disease. CONCLUSIONS This advance represents a critical step toward generating macroscale tissues, akin to aggregate-based organoids, but with the critical advantage of harboring geometric structures essential to the pump function of cardiac muscle. Looking forward, human chambered organoids of this type might also serve as a test bed for cardiac medical devices and eventually lead to therapeutic tissue grafting.
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Affiliation(s)
- Molly E Kupfer
- From the Department of Biomedical Engineering (M.E.K., W.-H.L., D.B.B., M.L., J.A., R.R.M., E.G.T., B.M.O.), University of Minnesota-Twin Cities, Minneapolis.,Stem Cell Institute (M.E.K., W.-H.L., B.M.O.), University of Minnesota-Twin Cities, Minneapolis
| | - Wei-Han Lin
- From the Department of Biomedical Engineering (M.E.K., W.-H.L., D.B.B., M.L., J.A., R.R.M., E.G.T., B.M.O.), University of Minnesota-Twin Cities, Minneapolis.,Stem Cell Institute (M.E.K., W.-H.L., B.M.O.), University of Minnesota-Twin Cities, Minneapolis
| | - Vasanth Ravikumar
- Department of Electrical Engineering (V.R.), University of Minnesota-Twin Cities, Minneapolis
| | - Kaiyan Qiu
- Department of Mechanical Engineering (K.Q., M.C.M.), University of Minnesota-Twin Cities, Minneapolis
| | - Lu Wang
- Department of Biomedical Engineering, School of Medicine, School of Engineering, University of Alabama at Birmingham (L.W., L.G., J.Z.)
| | - Ling Gao
- Department of Biomedical Engineering, School of Medicine, School of Engineering, University of Alabama at Birmingham (L.W., L.G., J.Z.)
| | - Didarul B Bhuiyan
- From the Department of Biomedical Engineering (M.E.K., W.-H.L., D.B.B., M.L., J.A., R.R.M., E.G.T., B.M.O.), University of Minnesota-Twin Cities, Minneapolis
| | - Megan Lenz
- From the Department of Biomedical Engineering (M.E.K., W.-H.L., D.B.B., M.L., J.A., R.R.M., E.G.T., B.M.O.), University of Minnesota-Twin Cities, Minneapolis
| | - Jeffrey Ai
- From the Department of Biomedical Engineering (M.E.K., W.-H.L., D.B.B., M.L., J.A., R.R.M., E.G.T., B.M.O.), University of Minnesota-Twin Cities, Minneapolis
| | - Ryan R Mahutga
- From the Department of Biomedical Engineering (M.E.K., W.-H.L., D.B.B., M.L., J.A., R.R.M., E.G.T., B.M.O.), University of Minnesota-Twin Cities, Minneapolis
| | - DeWayne Townsend
- Lillehei Heart Institute (D.T., E.G.T., B.M.O.), University of Minnesota-Twin Cities, Minneapolis.,Department of Integrative Biology and Physiology (D.T.), University of Minnesota-Twin Cities, Minneapolis
| | - Jianyi Zhang
- Department of Biomedical Engineering, School of Medicine, School of Engineering, University of Alabama at Birmingham (L.W., L.G., J.Z.)
| | - Michael C McAlpine
- Department of Mechanical Engineering (K.Q., M.C.M.), University of Minnesota-Twin Cities, Minneapolis
| | - Elena G Tolkacheva
- From the Department of Biomedical Engineering (M.E.K., W.-H.L., D.B.B., M.L., J.A., R.R.M., E.G.T., B.M.O.), University of Minnesota-Twin Cities, Minneapolis.,Lillehei Heart Institute (D.T., E.G.T., B.M.O.), University of Minnesota-Twin Cities, Minneapolis.,Institute for Engineering in Medicine (E.G.T., B.M.O.), University of Minnesota-Twin Cities, Minneapolis
| | - Brenda M Ogle
- From the Department of Biomedical Engineering (M.E.K., W.-H.L., D.B.B., M.L., J.A., R.R.M., E.G.T., B.M.O.), University of Minnesota-Twin Cities, Minneapolis.,Stem Cell Institute (M.E.K., W.-H.L., B.M.O.), University of Minnesota-Twin Cities, Minneapolis.,Lillehei Heart Institute (D.T., E.G.T., B.M.O.), University of Minnesota-Twin Cities, Minneapolis.,Institute for Engineering in Medicine (E.G.T., B.M.O.), University of Minnesota-Twin Cities, Minneapolis.,Masonic Cancer Center (B.M.O.), University of Minnesota-Twin Cities, Minneapolis
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13
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Abstract
In the 1950s, Arthur C. Guyton removed the heart from its pedestal in cardiovascular physiology by arguing that cardiac output is primarily regulated by the peripheral vasculature. This is counterintuitive, as modulating heart rate would appear to be the most obvious means of regulating cardiac output. In this Review, we visit recent and classic advances in comparative physiology in light of this concept. Although most vertebrates increase heart rate when oxygen demands rise (e.g. during activity or warming), experimental evidence suggests that this tachycardia is neither necessary nor sufficient to drive a change in cardiac output (i.e. systemic blood flow, Q̇ sys) under most circumstances. Instead, Q̇ sys is determined by the interplay between vascular conductance (resistance) and capacitance (which is mainly determined by the venous circulation), with a limited and variable contribution from heart function (myocardial inotropy). This pattern prevails across vertebrates; however, we also highlight the unique adaptations that have evolved in certain vertebrate groups to regulate venous return during diving bradycardia (i.e. inferior caval sphincters in diving mammals and atrial smooth muscle in turtles). Going forward, future investigation of cardiovascular responses to altered metabolic rate should pay equal consideration to the factors influencing venous return and cardiac filling as to the factors dictating cardiac function and heart rate.
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Affiliation(s)
- William Joyce
- Zoophysiology, Department of Bioscience, Aarhus University, 8000 Aarhus C, Denmark .,Department of Biology, University of Ottawa, 30 Marie Curie, Ottawa, ON K1N 6N5, Canada
| | - Tobias Wang
- Zoophysiology, Department of Bioscience, Aarhus University, 8000 Aarhus C, Denmark
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14
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Affiliation(s)
- Paul M L Janssen
- From the Department of Physiology and Cell Biology and D. Davis Heart Lung Research Institute, College of Medicine, The Ohio State University, Columbus.
| | - Brandon J Biesiadecki
- From the Department of Physiology and Cell Biology and D. Davis Heart Lung Research Institute, College of Medicine, The Ohio State University, Columbus
| | - Mark T Ziolo
- From the Department of Physiology and Cell Biology and D. Davis Heart Lung Research Institute, College of Medicine, The Ohio State University, Columbus
| | - Jonathan P Davis
- From the Department of Physiology and Cell Biology and D. Davis Heart Lung Research Institute, College of Medicine, The Ohio State University, Columbus
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15
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Lujan HL, Rivers JP, DiCarlo SE. A single electrical pulse within the protective zone of each cardiac cycle prevented reperfusion-induced ventricular tachycardia in conscious mice. Physiol Rep 2018; 6. [PMID: 29380958 PMCID: PMC5789730 DOI: 10.14814/phy2.13578] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Revised: 12/16/2017] [Accepted: 12/18/2017] [Indexed: 11/24/2022] Open
Abstract
Early pioneering investigators discovered, in anesthetized dogs, a protective period within the cardiac cycle. The protective period was a time within the cardiac cycle when a precisely timed stimulus prevented the initiation of ventricular fibrillation caused by an earlier stimulus. Thus, in addition to the susceptible period of repolarization discussed by Wiggers and Wegria (Am. J. Physiol. 131:296, 1940; Am. J. Physiol. 128:500, 1940), there is also a nearby protective period. This report describes a protective period within the cardiac cycle of conscious mice when a precisely timed stimulus prevented the initiation of ventricular tachycardia caused by an earlier stimulus. In addition, we tested the hypothesis that this precisely timed pulse within the protective period prevents reperfusion‐induced ventricular tachyarrhythmias in conscious mice. Mice (n = 6) were prepared to record arterial blood pressure and the electrocardiogram. In addition, a vascular occluder was placed around the left main coronary artery, and stimulating electrodes were secured onto the left ventricle. A single precisely timed electrical pulse (5 msec pulse width and 2.5 V) to the left ventricle arriving 13.9 ± 1.1 msec after the R‐wave, caused ventricular tachycardia occurring 24.9 ± 0.9 msec after the R‐wave. Importantly, a second precisely timed electrical pulse arriving 18.8 ± 0.5 msec after the first stimulus blocked the induction of ventricular tachycardia caused by the earlier stimulus. On an alternate day, the susceptibility to sustained ventricular tachycardia produced by 3.5 min of occlusion and reperfusion of the coronary artery was determined in conscious mice by use of the vascular occluder. Reperfusion resulted in ventricular tachycardia in all six mice. A precisely timed pulse within the protective period prevented ventricular tachycardia in all mice.
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Affiliation(s)
- Heidi L Lujan
- Department of Physiology, College of Osteopathic Medicine, Michigan State University, East Lansing, Michigan
| | - Joshua P Rivers
- Wayne State University School of Medicine, Detroit, Michigan
| | - Stephen E DiCarlo
- Department of Physiology, College of Osteopathic Medicine, Michigan State University, East Lansing, Michigan
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16
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Lujan HL, DiCarlo SE. Fundamental hemodynamic mechanisms mediating the response to myocardial ischemia in conscious paraplegic mice: cardiac output versus peripheral resistance. Physiol Rep 2017; 5:5/6/e13214. [PMID: 28336819 PMCID: PMC5371571 DOI: 10.14814/phy2.13214] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Revised: 02/21/2017] [Accepted: 02/22/2017] [Indexed: 11/25/2022] Open
Abstract
Autonomic dysfunction, a relative sedentary lifestyle, a reduced muscle mass and increased adiposity leads to metabolic abnormalities that accelerate the development of coronary artery disease (CAD) in individuals living with spinal cord injury (SCI). An untoward cardiac incident is related to the degree of CAD, suggesting that the occurrence of a significant cardiac event is significantly higher for individuals with SCI. Thus, understanding the fundamental hemodynamic mechanisms mediating the response to myocardial ischemia has the potential to positively impact individuals and families living with SCI. Accordingly, we systematically investigated if thoracic level 5 spinal cord transection (T5X; paraplegia) alters the arterial blood pressure response to coronary artery occlusion and if the different arterial blood pressure responses to coronary artery occlusion between intact and paraplegic mice are mediated by changes in cardiac output and or systemic peripheral resistance and whether differences in cardiac output are caused by changes in heart rate and or stroke volume. To achieve this goal, the tolerance to 3 min of coronary artery occlusion was determined in conscious intact and paraplegic mice. Paraplegic mice had an impaired ability to maintain arterial blood pressure during coronary artery occlusion as arterial pressure fell to near lethal levels by 1.38 ± 0.64 min. The lower arterial pressure was mediated by a lower cardiac output as systemic peripheral resistance was elevated in paraplegic mice. The lower cardiac output was mediated by a reduced heart rate and stroke volume. These results indicate that in paraplegic mice, the arterial pressure response to coronary artery occlusion is hemodynamically mediated primarily by cardiac output which is determined by heart rate and stroke volume.
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Affiliation(s)
- Heidi L Lujan
- Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan
| | - Stephen E DiCarlo
- Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan
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17
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Abstract
Numerous animal cardiac exercise models using animal subjects have been established to uncover the cardiovascular physiological mechanism of exercise or to determine the effects of exercise on cardiovascular health and disease. In most cases, animal-based cardiovascular exercise modalities include treadmill running, swimming, and voluntary wheel running with a series of intensities, times, and durations. Those used animals include small rodents (e.g., mice and rats) and large animals (e.g., rabbits, dogs, goats, sheep, pigs, and horses). Depending on the research goal, each experimental protocol should also describe whether its respective exercise treatment can produce the anticipated acute or chronic cardiovascular adaptive response. In this chapter, we will briefly describe the most common kinds of animal models of acute and chronic cardiovascular exercises that are currently being conducted and are likely to be chosen in the near future. Strengths and weakness of animal-based cardiac exercise modalities are also discussed.
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18
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Lujan HL, Rivers JP, DiCarlo SE. Complex and interacting influences of the autonomic nervous system on cardiac electrophysiology in conscious mice. Auton Neurosci 2016; 201:24-31. [PMID: 27594686 PMCID: PMC5108678 DOI: 10.1016/j.autneu.2016.08.017] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Revised: 08/15/2016] [Accepted: 08/28/2016] [Indexed: 01/09/2023]
Abstract
Mice may now be the preferred animal model for biomedical research due to its anatomical, physiological, and genetic similarity to humans. However, little is known about accentuated antagonism of chronotropic and dromotropic properties in conscious mice. Accordingly, we describe the complex and interacting influence of the autonomic nervous system on cardiac electrophysiology in conscious mice. Specifically, we report the effects of single and combined cardiac autonomic blockade on measurements of pulse interval (heart rate), atrio-ventricular interval, sinus node recovery time (SNRT), SNRT corrected for spontaneous sinus cycle, and Wenckebach cycle length in conscious mice free of the confounding influences of anesthetics and surgical trauma. Autonomic influences were quantified as the change in parameter induced by its selective blocker (Sympathetic or Parasympathetic Effect) or as the difference between the intrinsic value and the value after a selective blocker (Sympathetic or Parasympathetic Tonus). Sympatho-Vagal Balance (SVB) was assessed as the ratio of control interval to intrinsic interval. SVB suggests slight parasympathetic dominance in the control of cardiac electrophysiology intervals. Furthermore, results documents a complex interaction between the sympathetic and parasympathetic divisions of the autonomic nervous system in the control of cardiac electrophysiology parameters. Specifically, the parasympathetic effect was greater than the parasympathetic tonus in the control of cardiac electrophysiology parameters. In contrast, the sympathetic effect was smaller than the sympathetic tonus in the control of cardiac electrophysiology parameters. Results have important implications because actions of pharmacological agents that alter the autonomic control of cardiac electrophysiology are transformed by these interacting mechanisms.
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Affiliation(s)
- Heidi L Lujan
- Wayne State University School of Medicine, Department of Physiology, 540 E. Canfield Ave, Detroit, MI 48201, USA.
| | - Joshua P Rivers
- Wayne State University School of Medicine, Department of Physiology, 540 E. Canfield Ave, Detroit, MI 48201, USA.
| | - Stephen E DiCarlo
- Wayne State University School of Medicine, Department of Physiology, 540 E. Canfield Ave, Detroit, MI 48201, USA.
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19
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Roh J, Rhee J, Chaudhari V, Rosenzweig A. The Role of Exercise in Cardiac Aging: From Physiology to Molecular Mechanisms. Circ Res 2016; 118:279-95. [PMID: 26838314 DOI: 10.1161/circresaha.115.305250] [Citation(s) in RCA: 90] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Aging induces structural and functional changes in the heart that are associated with increased risk of cardiovascular disease and impaired functional capacity in the elderly. Exercise is a diagnostic and therapeutic tool, with the potential to provide insights into clinical diagnosis and prognosis, as well as the molecular mechanisms by which aging influences cardiac physiology and function. In this review, we first provide an overview of how aging impacts the cardiac response to exercise, and the implications this has for functional capacity in older adults. We then review the underlying molecular mechanisms by which cardiac aging contributes to exercise intolerance, and conversely how exercise training can potentially modulate aging phenotypes in the heart. Finally, we highlight the potential use of these exercise models to complement models of disease in efforts to uncover new therapeutic targets to prevent or treat heart disease in the aging population.
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Affiliation(s)
- Jason Roh
- From the Cardiovascular Division (J. Roh, J. Rhee, V.C., A.R.) and Department of Anesthesiology, Critical Care, and Pain Medicine (J. Rhee), Massachusetts General Hospital and Harvard Medical School, Boston
| | - James Rhee
- From the Cardiovascular Division (J. Roh, J. Rhee, V.C., A.R.) and Department of Anesthesiology, Critical Care, and Pain Medicine (J. Rhee), Massachusetts General Hospital and Harvard Medical School, Boston
| | - Vinita Chaudhari
- From the Cardiovascular Division (J. Roh, J. Rhee, V.C., A.R.) and Department of Anesthesiology, Critical Care, and Pain Medicine (J. Rhee), Massachusetts General Hospital and Harvard Medical School, Boston
| | - Anthony Rosenzweig
- From the Cardiovascular Division (J. Roh, J. Rhee, V.C., A.R.) and Department of Anesthesiology, Critical Care, and Pain Medicine (J. Rhee), Massachusetts General Hospital and Harvard Medical School, Boston.
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20
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Vogel B, Wagner H, Gmoser J, Wörner A, Löschberger A, Peters L, Frey A, Hofmann U, Frantz S. Touch-free measurement of body temperature using close-up thermography of the ocular surface. MethodsX 2016; 3:407-16. [PMID: 27284532 PMCID: PMC4887592 DOI: 10.1016/j.mex.2016.05.002] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2016] [Accepted: 05/04/2016] [Indexed: 11/28/2022] Open
Abstract
In experimental animal research body temperature (BT) is measured for the objective determination of an animals’ physiological condition. Invasive, probe-based measurements are stressful and can influence experimental outcome. Alternatively BT can be determined touch-free from the emitted heat of the organism at a single spot using infrared thermometers [1]. To get visual confirmation and find more appropriate surfaces for measurement a hand-held thermal imager was equipped with a self-made, cheap, 3D-printable close-up lens system that reproducibly creates eight-time magnified thermal images and improves sensitivity. This setup was used to establish ocular surface temperature (OST), representing the temperature of the brain-heart axis, as a touch-free alternative for measurement of BT in mice, rats, rabbits and humans.OST measurement after isoflurane exposure and myocardial infarction (MI) experiments in mice revealed high physiological relevance and sensitivity, the possibility to discriminate between MI and sham operations in one hour and even long-term outcome-predictive capabilities of OST after MI. Summarized here we present: Self-made close-up lens for thermal imaging cameras for eight-time magnification Establishment of OST for touch-free determination of BT in rodents and humans Short- and long-term predictive capabilities of OST in experimental MI in mice.
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Affiliation(s)
- Benjamin Vogel
- Comprehensive Heart Failure Center (CHCF), University Clinics of Würzburg, Germany; Center for Experimental Molecular Medicine, University of Würzburg, Germany
| | - Heike Wagner
- Center for Experimental Molecular Medicine, University of Würzburg, Germany
| | - Johanna Gmoser
- Department of Internal Medicine I, University Clinics of Würzburg, Germany
| | - Anja Wörner
- Department of Internal Medicine I, University Clinics of Würzburg, Germany
| | - Anna Löschberger
- Department of Experimental Biomedicine, University Clinics of Würzburg, Germany
| | - Laura Peters
- Department of Internal Medicine I, University Clinics of Würzburg, Germany
| | - Anna Frey
- Comprehensive Heart Failure Center (CHCF), University Clinics of Würzburg, Germany; Department of Internal Medicine I, University Clinics of Würzburg, Germany
| | - Ulrich Hofmann
- Comprehensive Heart Failure Center (CHCF), University Clinics of Würzburg, Germany; Department of Internal Medicine I, University Clinics of Würzburg, Germany; Universitätsklinik und Poliklinik für Innere Medizin III, University Clinics of Halle (Saale), Halle (Saale), Germany
| | - Stefan Frantz
- Universitätsklinik und Poliklinik für Innere Medizin III, University Clinics of Halle (Saale), Halle (Saale), Germany
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21
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Petrosino JM, Heiss VJ, Maurya SK, Kalyanasundaram A, Periasamy M, LaFountain RA, Wilson JM, Simonetti OP, Ziouzenkova O. Graded Maximal Exercise Testing to Assess Mouse Cardio-Metabolic Phenotypes. PLoS One 2016; 11:e0148010. [PMID: 26859763 PMCID: PMC4747552 DOI: 10.1371/journal.pone.0148010] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2015] [Accepted: 01/12/2016] [Indexed: 12/22/2022] Open
Abstract
Functional assessments of cardiovascular fitness (CVF) are needed to establish animal models of dysfunction, test the effects of novel therapeutics, and establish the cardio-metabolic phenotype of mice. In humans, the graded maximal exercise test (GXT) is a standardized diagnostic for assessing CVF and mortality risk. These tests, which consist of concurrent staged increases in running speed and inclination, provide diagnostic cardio-metabolic parameters, such as, VO2max, anaerobic threshold, and metabolic crossover. Unlike the human-GXT, published mouse treadmill tests have set, not staged, increases in inclination as speed progress until exhaustion (PXT). Additionally, they often lack multiple cardio-metabolic parameters. Here, we developed a mouse-GXT with the intent of improving mouse-exercise testing sensitivity and developing translatable parameters to assess CVF in healthy and dysfunctional mice. The mouse-GXT, like the human-GXT, incorporated staged increases in inclination, speed, and intensity; and, was designed by considering imitations of the PXT and differences between human and mouse physiology. The mouse-GXT and PXTs were both tested in healthy mice (C57BL/6J, FVBN/J) to determine their ability to identify cardio-metabolic parameters (anaerobic threshold, VO2max, metabolic crossover) observed in human-GXTs. Next, theses assays were tested on established diet-induced (obese-C57BL/6J) and genetic (cardiac isoform Casq2-/-) models of cardiovascular dysfunction. Results showed that both tests reported VO2max and provided reproducible data about performance. Only the mouse-GXT reproducibly identified anaerobic threshold, metabolic crossover, and detected impaired CVF in dysfunctional models. Our findings demonstrated that the mouse-GXT is a sensitive, non-invasive, and cost-effective method for assessing CVF in mice. This new test can be used as a functional assessment to determine the cardio-metabolic phenotype of various animal models or the effects of novel therapeutics.
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Affiliation(s)
- Jennifer M. Petrosino
- Department of Human Sciences, The Ohio State University, College of Education & Human Ecology, Columbus, Ohio, United States of America
- Biomedical Sciences Program, The Ohio State University, College of Medicine, Columbus, Ohio, United States of America
| | - Valerie J. Heiss
- Department of Human Sciences, The Ohio State University, College of Education & Human Ecology, Columbus, Ohio, United States of America
| | - Santosh K. Maurya
- Cardiovascular Pathobiology Program, Sanford Burnham Medical Research Institute at Lake Nona, Orland, Florida, United States of America
| | - Anuradha Kalyanasundaram
- Department of Physiology and Cell Biology, The Ohio State University College of Medicine, Columbus, Ohio, United States of America
| | - Muthu Periasamy
- Cardiovascular Pathobiology Program, Sanford Burnham Medical Research Institute at Lake Nona, Orland, Florida, United States of America
| | - Richard A. LaFountain
- Department of Human Sciences, The Ohio State University, College of Education & Human Ecology, Columbus, Ohio, United States of America
| | - Jacob M. Wilson
- Department of Human Performance, The University of Tampa, Tampa, Florida, United States of America
| | - Orlando P. Simonetti
- Department of Radiology, The Ohio State University, College of Medicine, Columbus, Ohio, United States of America
- Department of Cardiovascular Medicine, The Ohio State University, College of Medicine, Columbus, Ohio, United States of America
| | - Ouliana Ziouzenkova
- Department of Human Sciences, The Ohio State University, College of Education & Human Ecology, Columbus, Ohio, United States of America
- * E-mail:
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22
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Pulmonary Vascular and Airway Responses to Systemic Vasoconstrictors in Anesthetized BALB/c Mice. J Cardiovasc Pharmacol 2015; 65:325-34. [DOI: 10.1097/fjc.0000000000000199] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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23
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Cuomo F, Ferruzzi J, Humphrey JD, Figueroa CA. An Experimental-Computational Study of Catheter Induced Alterations in Pulse Wave Velocity in Anesthetized Mice. Ann Biomed Eng 2015; 43:1555-70. [PMID: 25698526 DOI: 10.1007/s10439-015-1272-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2014] [Accepted: 02/01/2015] [Indexed: 10/24/2022]
Abstract
Computational methods for solving problems of fluid dynamics and fluid-solid-interactions have advanced to the point that they enable reliable estimates of many hemodynamic quantities, including those important for studying vascular mechanobiology or designing medical devices. In this paper, we use a customized version of the open source code SimVascular to develop a computational model of central artery hemodynamics in anesthetized mice that is informed with experimental data on regional geometries, blood flows and pressures, and biaxial wall properties. After validating a baseline model against available data, we then use the model to investigate the effects of commercially available catheters on the very parameters that they are designed to measure, namely, murine blood pressure and (pressure) pulse wave velocity (PWV). We found that a combination of two small profile catheters designed to measure pressure simultaneously in the ascending aorta and femoral artery increased the PWV due to an overall increase in pressure within the arterial system. Conversely, a larger profile dual-sensor pressure catheter inserted through a carotid artery into the descending thoracic aorta decreased the PWV due to an overall decrease in pressure. In both cases, similar reductions in cardiac output were observed due to increased peripheral vascular resistance. As might be expected, therefore, invasive transducers can alter the very quantities that are designed to measure, yet advanced computational models offer a unique method to evaluate or augment such measurements.
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Affiliation(s)
- Federica Cuomo
- Department of Biomedical Engineering, King's College London, London, UK
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24
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Abstract
Exercise is the archetype of physiologic demands placed on the cardiovascular system. Acute responses provide an informative assessment of cardiovascular function and fitness, while repeated exercise promotes cardiovascular health and evokes important molecular, structural, and functional changes contributing to its effects in primary and secondary prevention. Here we examine the use of exercise in murine models, both as a phenotypic assay and as a provocative intervention. We first review the advantages and limitations of exercise testing for assessing cardiac function, then highlight the cardiac structural and cellular changes elicited by chronic exercise and key molecular pathways that mediate these effects.
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Affiliation(s)
- Colin Platt
- Cardiovascular Division of the Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA 02215
| | - Nicholas Houstis
- Cardiovascular Division, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02115
| | - Anthony Rosenzweig
- Cardiovascular Division of the Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA 02215.,Cardiovascular Division, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02115
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Wengrowski AM, Wang X, Tapa S, Posnack NG, Mendelowitz D, Kay MW. Optogenetic release of norepinephrine from cardiac sympathetic neurons alters mechanical and electrical function. Cardiovasc Res 2014; 105:143-50. [PMID: 25514932 DOI: 10.1093/cvr/cvu258] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
AIMS Release of norepinephrine (NE) from sympathetic neurons enhances heart rate (HR) and developed force through activation of β-adrenergic receptors, and this sympathoexcitation is a key risk for the generation of cardiac arrhythmias. Studies of β-adrenergic modulation of cardiac function typically involve the administration of exogenous β-adrenergic receptor agonists to directly elicit global β-adrenergic receptor activation by bypassing the involvement of sympathetic nerve terminals. In this work, we use a novel method to activate sympathetic fibres within the myocardium of Langendorff-perfused hearts while measuring changes in electrical and mechanical function. METHODS AND RESULTS The light-activated optogenetic protein channelrhodopsin-2 (ChR2) was expressed in murine catecholaminergic sympathetic neurons. Sympathetic fibres were then photoactivated to examine changes in contractile force, HR, and cardiac electrical activity. Incidence of arrhythmia was measured with and without exposure to photoactivation of sympathetic fibres, and hearts were optically mapped to detect changes in action potential durations and conduction velocities. Results demonstrate facilitation of both developed force and HR after photostimulated release of NE, with increases in contractile force and HR of 34.5 ± 5.5 and 25.0 ± 9.3%, respectively. Photostimulation of sympathetic fibres also made hearts more susceptible to arrhythmia, with greater incidence and severity. In addition, optically mapped action potentials displayed a small but significant shortening of the plateau phase (-5.5 ± 1.0 ms) after photostimulation. CONCLUSION This study characterizes a powerful and clinically relevant new model for studies of cardiac arrhythmias generated by increasing the activity of sympathetic nerve terminals and the resulting activation of myocyte β-adrenergic receptors.
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Affiliation(s)
- Anastasia M Wengrowski
- Department of Biomedical Engineering, The George Washington University, Phillips Hall, Room 607, 801 22nd Street NW, Washington, DC 20052, USA
| | - Xin Wang
- Department of Pharmacology and Physiology, The George Washington University, Washington, DC, USA
| | - Srinivas Tapa
- Department of Biomedical Engineering, The George Washington University, Phillips Hall, Room 607, 801 22nd Street NW, Washington, DC 20052, USA
| | - Nikki Gillum Posnack
- Department of Pharmacology and Physiology, The George Washington University, Washington, DC, USA
| | - David Mendelowitz
- Department of Pharmacology and Physiology, The George Washington University, Washington, DC, USA
| | - Matthew W Kay
- Department of Biomedical Engineering, The George Washington University, Phillips Hall, Room 607, 801 22nd Street NW, Washington, DC 20052, USA Department of Pharmacology and Physiology, The George Washington University, Washington, DC, USA
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Kurtz TW, Lujan HL, DiCarlo SE. The 24 h pattern of arterial pressure in mice is determined mainly by heart rate-driven variation in cardiac output. Physiol Rep 2014; 2:2/11/e12223. [PMID: 25428952 PMCID: PMC4255824 DOI: 10.14814/phy2.12223] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Few studies have systematically investigated whether daily patterns of arterial blood pressure over 24 h are mediated by changes in cardiac output, peripheral resistance, or both. Understanding the hemodynamic mechanisms that determine the 24 h patterns of blood pressure may lead to a better understanding of how such patterns become disturbed in hypertension and influence risk for cardiovascular events. In conscious, unrestrained C57BL/6J mice, we investigated whether the 24 h pattern of arterial blood pressure is determined by variation in cardiac output, systemic vascular resistance, or both and also whether variations in cardiac output are mediated by variations in heart rate and or stroke volume. As expected, arterial pressure and locomotor activity were significantly (P < 0.05) higher during the nighttime period compared with the daytime period when mice are typically sleeping (+12.5 ± 1.0 mmHg, [13%] and +7.7 ± 1.3 activity counts, [254%], respectively). The higher arterial pressure during the nighttime period was mediated by higher cardiac output (+2.6 ± 0.3 mL/min, [26%], P < 0.05) in association with lower peripheral resistance (-1.5 ± 0.3 mmHg/mL/min, [-13%] P < 0.05). The increased cardiac output during the nighttime was mainly mediated by increased heart rate (+80.0 ± 16.5 beats/min, [18%] P < 0.05), as stroke volume increased minimally at night (+1.6 ± 0.5 μL per beat, [6%] P < 0.05). These results indicate that in C57BL/6J mice, the 24 h pattern of blood pressure is hemodynamically mediated primarily by the 24 h pattern of cardiac output which is almost entirely determined by the 24 h pattern of heart rate. These findings suggest that the differences in blood pressure between nighttime and daytime are mainly driven by differences in heart rate which are strongly correlated with differences in locomotor activity.
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Affiliation(s)
- Theodore W Kurtz
- Department of Laboratory Medicine, University of California, San Francisco, San Francisco, California
| | - Heidi L Lujan
- Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan
| | - Stephen E DiCarlo
- Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan
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Lujan HL, DiCarlo SE. Reperfusion-induced sustained ventricular tachycardia, leading to ventricular fibrillation, in chronically instrumented, intact, conscious mice. Physiol Rep 2014; 2:2/6/e12057. [PMID: 24973331 PMCID: PMC4208649 DOI: 10.14814/phy2.12057] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Reperfusion‐induced lethal ventricular arrhythmias are observed during relief of coronary artery spasm, with unstable angina, exercise‐induced ischemia, and silent ischemia. Accordingly, significant efforts are underway to understand the mechanisms responsible for reperfusion‐induced lethal arrhythmias and mice have become increasingly important in these efforts. However, although reperfusion‐induced sustained ventricular tachycardia leading to ventricular fibrillation (VF) has been recorded in many models, reports in mice are sparse and of limited success. Importantly, none of these studies were conducted in intact, conscious mice. Accordingly, a chronically instrumented, intact, conscious murine model of reperfusion‐induced lethal arrhythmias has the potential to be of major importance for advancing the concepts and methods that drive cardiovascular therapies. Therefore, we describe, for the first time, the use of an intact, conscious, murine model of reperfusion‐induced lethal arrhythmias. Male mice (n = 9) were instrumented to record cardiac output and the electrocardiogram. In addition, a snare was placed around the left main coronary artery. Following recovery, the susceptibility to sustained ventricular tachycardia produced by 3 min of occlusion and reperfusion of the left main coronary artery was determined in conscious mice by pulling on the snare. Reperfusion culminated in sustained ventricular tachycardia, leading to VF, in all nine conscious mice. The procedures conducted in conscious C57BL/6J mice, a strain commonly used in transgenic studies, can be utilized in genetically modified models to enhance our understanding of single gene defects on reperfusion‐induced lethal ventricular arrhythmias in intact, conscious, and complex animals. We describe, for the first time, the use of an intact, conscious, murine model of reperfusion‐induced lethal arrhythmias. This model has the potential to be of major importance for advancing the concepts and methods that drive antiarrhythmic therapies.
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Affiliation(s)
- Heidi L Lujan
- Department of Physiology, Wayne State University School of Medicine, Detroit, 48201, Michigan
| | - Stephen E DiCarlo
- Department of Physiology, Wayne State University School of Medicine, Detroit, 48201, Michigan
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Lujan HL, Janbaih H, DiCarlo SE. Structural remodeling of the heart and its premotor cardioinhibitory vagal neurons following T(5) spinal cord transection. J Appl Physiol (1985) 2014; 116:1148-55. [PMID: 24610530 PMCID: PMC4097824 DOI: 10.1152/japplphysiol.01285.2013] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2013] [Accepted: 02/28/2014] [Indexed: 12/24/2022] Open
Abstract
Midthoracic spinal cord injury (SCI) is associated with enhanced cardiac sympathetic activity and reduced cardiac parasympathetic activity. The enhanced cardiac sympathetic activity is associated with sympathetic structural plasticity within the stellate ganglia, spinal cord segments T1-T4, and heart. However, changes to cardiac parasympathetic centers rostral to an experimental SCI are relatively unknown. Importantly, reduced vagal activity is a predictor of high mortality. Furthermore, this autonomic dysregulation promotes progressive left ventricular (LV) structural remodeling. Accordingly, we hypothesized that midthoracic spinal cord injury is associated with structural plasticity in premotor (preganglionic parasympathetic neurons) cardioinhibitory vagal neurons located within the nucleus ambiguus as well as LV structural remodeling. To test this hypothesis, dendritic arborization and morphology (cholera toxin B immunohistochemistry and Sholl analysis) of cardiac projecting premotor cardioinhibitory vagal neurons located within the nucleus ambiguus were determined in intact (sham transected) and thoracic level 5 transected (T5X) rats. In addition, LV chamber size, wall thickness, and collagen content (Masson trichrome stain and structural analysis) were determined. Midthoracic SCI was associated with structural changes within the nucleus ambiguus and heart. Specifically, following T5 spinal cord transection, there was a significant increase in cardiac parasympathetic preganglionic neuron dendritic arborization, soma area, maximum dendritic length, and number of intersections/animal. This parasympathetic structural remodeling was associated with a profound LV structural remodeling. Specifically, T5 spinal cord transection increased LV chamber area, reduced LV wall thickness, and increased collagen content. Accordingly, results document a dynamic interaction between the heart and its parasympathetic innervation.
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Affiliation(s)
- Heidi L Lujan
- Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan
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Lujan HL, DiCarlo SE. Cardiac electrophysiology and the susceptibility to sustained ventricular tachycardia in intact, conscious mice. Am J Physiol Heart Circ Physiol 2014; 306:H1213-21. [PMID: 24561859 DOI: 10.1152/ajpheart.00780.2013] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Cardiac electrophysiological dysfunction is a major cause of death in humans. Accordingly, electrophysiological testing is routinely performed in intact, conscious, humans to evaluate arrhythmias and disorders of cardiac conduction. However, to date, in vivo electrophysiological studies in mice are limited to anesthetized open-chest or closed-chest preparations. However, cardiac electrophysiology in anesthetized mice or mice with surgical trauma may not adequately represent what occurs in conscious mice. Accordingly, an intact, conscious murine model of cardiac electrophysiology has the potential to be of major importance for advancing the concepts and methods that drive cardiovascular therapies. Therefore, we describe, for the first time, the use of an intact, conscious, murine model of cardiac electrophysiology. The conscious mouse model permits measurements of atrioventricular interval, sinus cycle length, sinus node recovery time (SNRT), SNRT corrected for spontaneous sinus cycle, Wenckebach cycle length, the ventricular effective refractory period (VERP) and the electrical stimulation threshold to induce sustained ventricular tachyarrhythmias in an intact, complex model free of the confounding influences of anesthetics and surgical trauma. This is an important consideration because anesthesia and surgical trauma markedly reduced cardiac output and heart rate as well as altered cardiac electrophysiology parameters. Most importantly, anesthesia and surgical trauma significantly increased the VERP and virtually eliminated the ability to induce sustained ventricular tachyarrhythmias. Accordingly, the methodology allows for the accurate documentation of cardiac electrophysiology in complex, conscious mice and may be adopted for advancing the concepts and ideas that drive cardiovascular research.
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Affiliation(s)
- Heidi L Lujan
- Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan
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