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Sanfilippo F, Messina A, Scolletta S, Bignami E, Morelli A, Cecconi M, Landoni G, Romagnoli S. The "CHEOPS" bundle for the management of Left Ventricular Diastolic Dysfunction in critically ill patients: an experts' opinion. Anaesth Crit Care Pain Med 2023; 42:101283. [PMID: 37516408 DOI: 10.1016/j.accpm.2023.101283] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2023] [Revised: 07/18/2023] [Accepted: 07/19/2023] [Indexed: 07/31/2023]
Abstract
The impact of left ventricular (LV) diastolic dysfunction (DD) on the outcome of patients with heart failure was established over three decades ago. Nevertheless, the relevance of LVDD for critically ill patients admitted to the intensive care unit has seen growing interest recently, and LVDD is associated with poor prognosis. Whilst an assessment of LV diastolic function is desirable in critically ill patients, treatment options for LVDD are very limited, and pharmacological possibilities to rapidly optimize diastolic function have not been found yet. Hence, a proactive approach might have a substantial role in improving the outcomes of these patients. Recalling historical Egyptian parallelism suggesting that Doppler echocardiography has been the "Rosetta stone" to decipher the study of LV diastolic function, we developed a potentially useful acronym for physicians at the bedside to optimize the management of critically ill patients with LVDD with the application of the bundle. We summarized the bundle under the acronym of the famous ancient Egyptian pharaoh CHEOPS: Chest Ultrasound, combining information from echocardiography and lung ultrasound; HEmodynamics assessment, with careful evaluation of heart rate and rhythm, as well as afterload and vasoactive drugs; OPtimization of mechanical ventilation and pulmonary circulation, considering the effects of positive end-expiratory pressure on both right and left heart function; Stabilization, with cautious fluid administration and prompt fluid removal whenever judged safe and valuable. Notably, the CHEOPS bundle represents experts' opinion and are not targeted at the initial resuscitation phase but rather for the optimization and subsequent period of critical illness.
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Affiliation(s)
- Filippo Sanfilippo
- Department of Anaesthesia and Intensive Care, A.O.U. Policlinico-San Marco, Catania, Italy; Department of General Surgery and Medico-Surgical Specialties, School of Anaesthesia and Intensive Care, University of Catania, Catania, Italy.
| | - Antonio Messina
- Department of Anesthesia and Intensive Care Medicine, Humanitas Clinical and Research Center IRCCS, 20089, Rozzano, Milan, Italy.
| | - Sabino Scolletta
- Anesthesia and Intensive Care Unit, University Hospital of Siena, University of Siena, Siena, Italy.
| | - Elena Bignami
- Anesthesiology, Critical Care and Pain Medicine Division, Department of Medicine and Surgery, University of Parma, Parma, Italy.
| | - Andrea Morelli
- Department Clinical Internal, Anesthesiological and Cardiovascular Sciences, University of Rome, "La Sapienza", Policlinico Umberto Primo, Roma, Italy.
| | - Maurizio Cecconi
- Department of Anesthesia and Intensive Care Medicine, Humanitas Clinical and Research Center IRCCS, 20089, Rozzano, Milan, Italy.
| | - Giovanni Landoni
- Department of Anesthesia and Intensive Care, IRCCS San Raffaele Scientific Institute, Faculty of Medicine, Vita-Salute San Raffaele University, Milan, Italy.
| | - Stefano Romagnoli
- Department of Health Science, Section of Anaesthesia and Intensive Care, University of Florence, Department of Anetshesia and Critical Care, Azienda Ospedaliero-Universitaria Careggi, Florence, Italy.
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Salameh S, Ogueri V, Posnack NG. Adapting to a new environment: postnatal maturation of the human cardiomyocyte. J Physiol 2023; 601:2593-2619. [PMID: 37031380 PMCID: PMC10775138 DOI: 10.1113/jp283792] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Accepted: 03/16/2023] [Indexed: 04/10/2023] Open
Abstract
The postnatal mammalian heart undergoes remarkable developmental changes, which are stimulated by the transition from the intrauterine to extrauterine environment. With birth, increased oxygen levels promote metabolic, structural and biophysical maturation of cardiomyocytes, resulting in mature muscle with increased efficiency, contractility and electrical conduction. In this Topical Review article, we highlight key studies that inform our current understanding of human cardiomyocyte maturation. Collectively, these studies suggest that human atrial and ventricular myocytes evolve quickly within the first year but might not reach a fully mature adult phenotype until nearly the first decade of life. However, it is important to note that fetal, neonatal and paediatric cardiac physiology studies are hindered by a number of limitations, including the scarcity of human tissue, small sample size and a heavy reliance on diseased tissue samples, often without age-matched healthy controls. Future developmental studies are warranted to expand our understanding of normal cardiac physiology/pathophysiology and inform age-appropriate treatment strategies for cardiac disease.
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Affiliation(s)
- Shatha Salameh
- Department of Pharmacology & Physiology, George Washington University, Washington, DC, USA
- Sheikh Zayed Institute for Pediatric Surgical Innovation, Children’s National Hospital, Washington, DC, USA
| | - Vanessa Ogueri
- Children’s National Heart Institute, Children’s National Hospital, Washington, DC, USA
| | - Nikki Gillum Posnack
- Department of Pharmacology & Physiology, George Washington University, Washington, DC, USA
- Sheikh Zayed Institute for Pediatric Surgical Innovation, Children’s National Hospital, Washington, DC, USA
- Children’s National Heart Institute, Children’s National Hospital, Washington, DC, USA
- Department of Pediatrics, George Washington University, Washington, DC, USA
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3
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Mora MT, Zaza A, Trenor B. Insights from an electro-mechanical heart failure cell model: Role of SERCA enhancement on arrhythmogenesis and myocyte contraction. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2023; 230:107350. [PMID: 36689807 DOI: 10.1016/j.cmpb.2023.107350] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Revised: 12/27/2022] [Accepted: 01/10/2023] [Indexed: 06/17/2023]
Abstract
BACKGROUND AND OBJECTIVE Structural and electrical remodeling in heart failure predisposes the heart to ventricular arrhythmias. Computer modeling approaches, used to complement experimental results, can provide a more mechanistic knowledge of the biophysical phenomena underlying cardiac pathologies. Indeed, previous in-silico studies have improved the understanding of the electrical correlates of heart failure involved in arrhythmogenesis; however, information on the crosstalk between electrical activity, intracellular Ca2+ and contraction is still incomplete. This study aims to investigate the electro-mechanical behavior of virtual failing human ventricular myocytes to help in the development of therapies, which should ideally target pump failure and arrhythmias at the same time. METHODS We implemented characteristic remodeling of heart failure with reduced ejection fraction by including reported changes in ionic conductances, sarcomere function and cell structure (e.g. T-tubules disarray). Model parametrization was based on published experimental data and the outcome of simulations was validated against experimentally observed patterns. We focused on two aspects of myocardial dysfunction central in heart failure: altered force-frequency relationship and susceptibility to arrhythmogenic early afterdepolarizations. Because biological variability is a major problem in the generalization of in-silico findings based on a unique set of model parameters, we generated and evaluated a population of models. RESULTS The population-based approach is crucial in robust identification of parameters at the core of abnormalities and in generalizing the outcome of their correction. As compared to non-failing ones, failing myocytes had prolonged repolarization, a higher incidence of early afterdepolarizations, reduced contraction and a shallower force-frequency relationship, all features peculiar of heart failure. Component analysis applied to the model population identified reduced SERCA function as a relevant contributor to most of these derangements, which were largely reverted or diminished by restoration of SERCA function alone. CONCLUSIONS These simulated results encourage the development of strategies comprising SERCA stimulation and highlight the need to evaluate both electrical and mechanical outcomes.
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Affiliation(s)
- Maria Teresa Mora
- Centro de Investigación e Innovación en Bioingeniería, Universitat Politècnica de València, Valencia, Spain
| | - Antonio Zaza
- Dipartimento di Biotecnologie e Bioscienze, Università degli Studi Milano-Bicocca, Italy; Unità di Fisiologia Cardiovascolare, IRCCs Istituto Auxologico Italiano, Italy
| | - Beatriz Trenor
- Centro de Investigación e Innovación en Bioingeniería, Universitat Politècnica de València, Valencia, Spain.
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Skeletal and cardiac muscle calcium transport regulation in health and disease. Biosci Rep 2022; 42:232141. [PMID: 36413081 DOI: 10.1042/bsr20211997] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Revised: 11/04/2022] [Accepted: 11/22/2022] [Indexed: 11/23/2022] Open
Abstract
In healthy muscle, the rapid release of calcium ions (Ca2+) with excitation-contraction (E-C) coupling, results in elevations in Ca2+ concentrations which can exceed 10-fold that of resting values. The sizable transient changes in Ca2+ concentrations are necessary for the activation of signaling pathways, which rely on Ca2+ as a second messenger, including those involved with force generation, fiber type distribution and hypertrophy. However, prolonged elevations in intracellular Ca2+ can result in the unwanted activation of Ca2+ signaling pathways that cause muscle damage, dysfunction, and disease. Muscle employs several calcium handling and calcium transport proteins that function to rapidly return Ca2+ concentrations back to resting levels following contraction. This review will detail our current understanding of calcium handling during the decay phase of intracellular calcium transients in healthy skeletal and cardiac muscle. We will also discuss how impairments in Ca2+ transport can occur and how mishandling of Ca2+ can lead to the pathogenesis and/or progression of skeletal muscle myopathies and cardiomyopathies.
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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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Ahmadian M, Williams AM, Mannozzi J, Konecny F, Hoiland RL, Wainman L, Erskine E, Duffy J, Manouchehri N, So K, Tauh K, Sala-Mercado JA, Shortt K, Fisk S, Kim KT, Streijger F, Foster GE, Kwon BK, O’Leary DS, West CR. A cross-species validation of single-beat metrics of cardiac contractility. J Physiol 2022; 600:4779-4806. [PMID: 36121759 PMCID: PMC9669232 DOI: 10.1113/jp283319] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Accepted: 09/02/2022] [Indexed: 12/24/2022] Open
Abstract
The assessment of left ventricular (LV) contractility in animal models is useful in various experimental paradigms, yet obtaining such measures is inherently challenging and surgically invasive. In a cross-species study using small and large animals, we comprehensively tested the agreement and validity of multiple single-beat surrogate metrics of LV contractility against the field-standard metrics derived from inferior vena cava occlusion (IVCO). Fifty-six rats, 27 minipigs and 11 conscious dogs underwent LV and arterial catheterization and were assessed for a range of single-beat metrics of LV contractility. All single-beat metrics were tested for the various underlying assumptions required to be considered a valid metric of cardiac contractility, including load-independency, sensitivity to inotropic stimulation, and ability to diagnose contractile dysfunction in cardiac disease. Of all examined single-beat metrics, only LV maximal pressure normalized to end-diastolic volume (EDV), end-systolic pressure normalized to EDV, and the maximal rate of rise of the LV pressure normalized to EDV showed a moderate-to-excellent agreement with their IVCO-derived reference measure and met all the underlying assumptions required to be considered as a valid cardiac contractile metric in both rodents and large-animal models. Our findings demonstrate that single-beat metrics can be used as a valid, reliable method to quantify cardiac contractile function in basic/preclinical experiments utilizing small- and large-animal models KEY POINTS: Validating and comparing indices of cardiac contractility that avoid caval occlusion would offer considerable advantages for the field of cardiovascular physiology. We comprehensively test the underlying assumptions of multiple single-beat indices of cardiac contractility in rodents and translate these findings to pigs and conscious dogs. We show that when performing caval occlusion is unfeasible, single-beat metrics can be utilized to accurately quantify cardiac inotropic function in basic and preclinical research employing various small and large animal species. We report that maximal left-ventricular (LV)-pressure normalized to end-diastolic volume (EDV), LV end-systolic pressure normalized to EDV and the maximal rate of rise of the LV pressure waveform normalized to EDV are the best three single-beat metrics to measure cardiac inotropic function in both small- and large-animal models.
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Affiliation(s)
- Mehdi Ahmadian
- School of Kinesiology, Faculty of Education, University of British Columbia, Vancouver, BC, Canada
- International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, BC, Canada
- Centre for Chronic Disease Prevention and Management, University of British Columbia, Kelowna, BC, Canada
| | - Alexandra M. Williams
- International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, BC, Canada
- Department of Cellular and Physiological Sciences, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Joseph Mannozzi
- Department of Physiology, School of Medicine, Wayne State University, Detroit, MI 48009
| | - Filip Konecny
- Transonic Scisense Inc., London, ON, Canada
- MaRS Centre Toronto Medical Discovery Tower, 3rd Floor, 101 College Street, M5G 1L7, Toronto, Ontario, Canada
| | - Ryan L. Hoiland
- International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, BC, Canada
- Department of Cellular and Physiological Sciences, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada
- Department of Anesthesiology, Pharmacology and Therapeutics, Faculty of Medicine, Vancouver General Hospital, 899 West 12th Avenue, University of British Columbia, Vancouver, BC, Canada, V5Z 1M9
| | - Liisa Wainman
- International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, BC, Canada
- Centre for Chronic Disease Prevention and Management, University of British Columbia, Kelowna, BC, Canada
- Department of Cellular and Physiological Sciences, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Erin Erskine
- International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, BC, Canada
- Centre for Chronic Disease Prevention and Management, University of British Columbia, Kelowna, BC, Canada
- Department of Cellular and Physiological Sciences, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Jennifer Duffy
- International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, BC, Canada
- Centre for Chronic Disease Prevention and Management, University of British Columbia, Kelowna, BC, Canada
- Department of Cellular and Physiological Sciences, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Neda Manouchehri
- International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, BC, Canada
| | - Kitty So
- International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, BC, Canada
| | - Keerit Tauh
- International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, BC, Canada
| | | | - Katelyn Shortt
- International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, BC, Canada
| | - Shera Fisk
- International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, BC, Canada
| | - Kyoung-Tae Kim
- International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, BC, Canada
- Department of Neurosurgery, School of Medicine, Kyungpook National University Hospital, Daegu, South Korea
| | - Femke Streijger
- International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, BC, Canada
| | - Glen E. Foster
- Centre for Heart, Lung, & Vascular Health, School of Health and Exercise Sciences, University of British Columbia Okanagan, 3333 University Way, Kelowna, BC, V1V1V7
| | - Brian K. Kwon
- International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, BC, Canada
| | - Donal S. O’Leary
- Department of Physiology, School of Medicine, Wayne State University, Detroit, MI 48009
| | - Christopher R. West
- International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, BC, Canada
- Centre for Chronic Disease Prevention and Management, University of British Columbia, Kelowna, BC, Canada
- Department of Cellular and Physiological Sciences, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada
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Paudel R, Jafri MS, Ullah A. The Role of Ca 2+ Sparks in Force Frequency Relationships in Guinea Pig Ventricular Myocytes. Biomolecules 2022; 12:1577. [PMID: 36358926 PMCID: PMC9687237 DOI: 10.3390/biom12111577] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2022] [Revised: 10/19/2022] [Accepted: 10/21/2022] [Indexed: 10/13/2023] Open
Abstract
Calcium sparks are the elementary Ca2+ release events in excitation-contraction coupling that underlie the Ca2+ transient. The frequency-dependent contractile force generated by cardiac myocytes depends upon the characteristics of the Ca2+ transients. A stochastic computational local control model of a guinea pig ventricular cardiomyocyte was developed, to gain insight into mechanisms of force-frequency relationship (FFR). This required the creation of a new three-state RyR2 model that reproduced the adaptive behavior of RyR2, in which the RyR2 channels transition into a different state when exposed to prolonged elevated subspace [Ca2+]. The model simulations agree with previous experimental and modeling studies on interval-force relations. Unlike previous common pool models, this local control model displayed stable action potential trains at 7 Hz. The duration and the amplitude of the [Ca2+]myo transients increase in pacing rates consistent with the experiments. The [Ca2+]myo transient reaches its peak value at 4 Hz and decreases afterward, consistent with experimental force-frequency curves. The model predicts, in agreement with previous modeling studies of Jafri and co-workers, diastolic sarcoplasmic reticulum, [Ca2+]sr, and RyR2 adaptation increase with the increased stimulation frequency, producing rising, rather than falling, amplitude of the myoplasmic [Ca2+] transients. However, the local control model also suggests that the reduction of the L-type Ca2+ current, with an increase in pacing frequency due to Ca2+-dependent inactivation, also plays a role in the negative slope of the FFR. In the simulations, the peak Ca2+ transient in the FFR correlated with the highest numbers of SR Ca2+ sparks: the larger average amplitudes of those sparks, and the longer duration of the Ca2+ sparks.
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Affiliation(s)
- Roshan Paudel
- School of Systems Biology, George Mason University, Fairfax, VA 22030, USA
- School of Computer, Mathematical, and Natural Sciences, Morgan State University, Baltimore, MD 21251, USA
| | - Mohsin Saleet Jafri
- School of Systems Biology, George Mason University, Fairfax, VA 22030, USA
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD 20201, USA
| | - Aman Ullah
- School of Systems Biology, George Mason University, Fairfax, VA 22030, USA
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Topal L, Polyák A, Tóth N, Ágoston G, Bencsik P, Kohajda Z, Prorok J, Déri S, Nagy N, Jost N, Virág L, Farkas AS, Varró A, Baczkó I. Endurance training-induced cardiac remodeling in a guinea pig athlete's heart model. Can J Physiol Pharmacol 2022; 100:993-1004. [PMID: 35834825 DOI: 10.1139/cjpp-2022-0073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Besides the health benefits of regular exercise, high-level training-above an optimal level-may have adverse effects. In this study, we investigated the effects of long-term vigorous training and its potentially detrimental structural-functional changes in a small animal athlete's heart model. Thirty-eight 4-month-old male guinea pigs were randomized into sedentary and exercised groups. The latter underwent a 15-week-long endurance-training program. To investigate the effects of the intense long-term exercise, in vivo (echocardiography, electrocardiography), ex vivo, and in vitro (histopathology, patch-clamp) measurements were performed. Following the training protocol, the exercised animals exhibited structural left ventricular enlargement and a significantly higher degree of myocardial fibrosis. Furthermore, resting bradycardia accompanied by elevated heart rate variability occurred, representing increased parasympathetic activity in the exercised hearts. The observed prolonged QTc intervals and increased repolarization variability parameters may raise the risk of electrical instability in exercised animals. Complex arrhythmias did not occur in either group, and there were no differences between the groups in ex vivo or cellular electrophysiological experiments. Accordingly, the high parasympathetic activity may promote impaired repolarization in conscious exercised animals. The detected structural-functional changes share similarities with the human athlete's heart; therefore, this model might be useful for investigations on cardiac remodeling.
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Affiliation(s)
- L Topal
- Department of Pharmacology and Pharmacotherapy, University of Szeged, Szeged, 6720, Hungary
| | - A Polyák
- Department of Pharmacology and Pharmacotherapy, University of Szeged, Szeged, 6720, Hungary
- Department of Pediatrics and Pediatric Health Center, University of Szeged, Szeged, 6725, Hungary
| | - N Tóth
- Department of Pharmacology and Pharmacotherapy, University of Szeged, Szeged, 6720, Hungary
| | - G Ágoston
- Institute of Family Medicine, University of Szeged, Szeged, 6720, Hungary
| | - P Bencsik
- Department of Pharmacology and Pharmacotherapy, University of Szeged, Szeged, 6720, Hungary
| | - Zs Kohajda
- ELKH-SZTE Research Group of Cardiovascular Pharmacology, Szeged, Hungary
| | - J Prorok
- Department of Pharmacology and Pharmacotherapy, University of Szeged, Szeged, 6720, Hungary
- ELKH-SZTE Research Group of Cardiovascular Pharmacology, Szeged, Hungary
| | - Sz Déri
- Department of Pharmacology and Pharmacotherapy, University of Szeged, Szeged, 6720, Hungary
| | - N Nagy
- Department of Pharmacology and Pharmacotherapy, University of Szeged, Szeged, 6720, Hungary
- ELKH-SZTE Research Group of Cardiovascular Pharmacology, Szeged, Hungary
| | - N Jost
- Department of Pharmacology and Pharmacotherapy, University of Szeged, Szeged, 6720, Hungary
- ELKH-SZTE Research Group of Cardiovascular Pharmacology, Szeged, Hungary
- Department of Pharmacology and Pharmacotherapy, Interdisciplinary Excellence Centre, University of Szeged, Szeged, 6720, Hungary
| | - L Virág
- Department of Pharmacology and Pharmacotherapy, University of Szeged, Szeged, 6720, Hungary
- Department of Pharmacology and Pharmacotherapy, Interdisciplinary Excellence Centre, University of Szeged, Szeged, 6720, Hungary
| | - A S Farkas
- Department of Internal Medicine, Cardiology, University of Szeged, Szeged, 6725, Hungary
| | - A Varró
- Department of Pharmacology and Pharmacotherapy, University of Szeged, Szeged, 6720, Hungary
- ELKH-SZTE Research Group of Cardiovascular Pharmacology, Szeged, Hungary
- Department of Pharmacology and Pharmacotherapy, Interdisciplinary Excellence Centre, University of Szeged, Szeged, 6720, Hungary
| | - I Baczkó
- Department of Pharmacology and Pharmacotherapy, University of Szeged, Szeged, 6720, Hungary
- Department of Pharmacology and Pharmacotherapy, Interdisciplinary Excellence Centre, University of Szeged, Szeged, 6720, Hungary
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9
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Bartolucci C, Forouzandehmehr M, Severi S, Paci M. A Novel In Silico Electromechanical Model of Human Ventricular Cardiomyocyte. Front Physiol 2022; 13:906146. [PMID: 35721558 PMCID: PMC9198403 DOI: 10.3389/fphys.2022.906146] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Accepted: 05/10/2022] [Indexed: 11/25/2022] Open
Abstract
Contractility has become one of the main readouts in computational and experimental studies on cardiomyocytes. Following this trend, we propose a novel mathematical model of human ventricular cardiomyocytes electromechanics, BPSLand, by coupling a recent human contractile element to the BPS2020 model of electrophysiology. BPSLand is the result of a hybrid optimization process and it reproduces all the electrophysiology experimental indices captured by its predecessor BPS2020, simultaneously enabling the simulation of realistic human active tension and its potential abnormalities. The transmural heterogeneity in both electrophysiology and contractility departments was simulated consistent with previous computational and in vitro studies. Furthermore, our model could capture delayed afterdepolarizations (DADs), early afterdepolarizations (EADs), and contraction abnormalities in terms of aftercontractions triggered by either drug action or special pacing modes. Finally, we further validated the mechanical results of the model against previous experimental and in silico studies, e.g., the contractility dependence on pacing rate. Adding a new level of applicability to the normative models of human cardiomyocytes, BPSLand represents a robust, fully-human in silico model with promising capabilities for translational cardiology.
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Affiliation(s)
- Chiara Bartolucci
- Computational Physiopathology Unit, Department of Electrical, Electronic and Information Engineering "Guglielmo Marconi", University of Bologna, Bologna, Italy
| | | | - Stefano Severi
- Computational Physiopathology Unit, Department of Electrical, Electronic and Information Engineering "Guglielmo Marconi", University of Bologna, Bologna, Italy
| | - Michelangelo Paci
- BioMediTech, Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland
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10
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Yuchi Y, Suzuki R, Kanno H, Saito T, Teshima T, Matsumoto H, Koyama H. Influence of heart rate on right ventricular function assessed by right heart catheterization and echocardiography in healthy anesthetized dogs. BMC Vet Res 2022; 18:166. [PMID: 35524303 PMCID: PMC9074250 DOI: 10.1186/s12917-022-03271-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Accepted: 04/28/2022] [Indexed: 12/04/2022] Open
Abstract
Background Right ventricular (RV) functional assessment has received considerable attention in veterinary medicine since various diseases, such as cardiovascular, respiratory, endocrine, and neoplastic disease, may affect RV function. Heart rate (HR) is an important factor that can influence RV function through changes in loading condition and contractility. However, no study has yet evaluated the association between HR and RV function in the same individuals. This study aimed to evaluate the influence of elevated HR on RV function using right heart catheterization and echocardiography, and investigate the association between right heart catheterization and echocardiographic indices. Results Right atrial pacing was performed in eight dogs at 120, 140, 160, and 180 bpm. With an increase in HR, the RV systolic volume, RV diastolic volume, and stroke volume significantly decreased; however, the cardiac output, end-systolic elastance (Ees), and effective arterial elastance (Ea) significantly increased. Significant changes were not observed in RV pressure and Ees/Ea. The RV area normalized by body weight, RV fractional area change normalized by body weight (RV FACn), and tricuspid annular plane systolic excursion normalized by body weight (TAPSEn) significantly decreased with increased HR. Peak systolic myocardial velocity of the lateral tricuspid annulus (RV s’), RV strain, and RV strain rate of only the RV free wall analysis (RV-SrL3seg) showed no significant changes with the increase in HR; however, there was an increase in the RV strain rate of the RV global analysis (RV-SrL6seg). Multiple regression analysis revealed that HR, RV FACn, and RV- SrL6seg had significant associations with the Ees, and the TAPSEn and RV-SrL3seg with Ees/Ea. Conclusions Decreased venous return and shortened relaxation time decreased the RV FAC, TAPSE, RV s’, and RV strain, and might underestimate the RV function. Ees increased with the increase in HR, reflecting the myocardial force-frequency relation; as a result, RV-SrL6seg could be a useful tool for Ees estimation. Additionally, the RV-SrL3seg could detect RV performance, reflecting the balance between RV contractility and RV afterload.
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Affiliation(s)
- Yunosuke Yuchi
- Laboratory of Veterinary Internal Medicine, School of Veterinary Medicine, Faculty of Veterinary Science, Nippon Veterinary and Life Science University, 1-7-1 Kyonan-cho, Musashino-shi, Tokyo, 180-8602, Japan
| | - Ryohei Suzuki
- Laboratory of Veterinary Internal Medicine, School of Veterinary Medicine, Faculty of Veterinary Science, Nippon Veterinary and Life Science University, 1-7-1 Kyonan-cho, Musashino-shi, Tokyo, 180-8602, Japan.
| | - Haruka Kanno
- Laboratory of Veterinary Internal Medicine, School of Veterinary Medicine, Faculty of Veterinary Science, Nippon Veterinary and Life Science University, 1-7-1 Kyonan-cho, Musashino-shi, Tokyo, 180-8602, Japan
| | - Takahiro Saito
- Laboratory of Veterinary Internal Medicine, School of Veterinary Medicine, Faculty of Veterinary Science, Nippon Veterinary and Life Science University, 1-7-1 Kyonan-cho, Musashino-shi, Tokyo, 180-8602, Japan
| | - Takahiro Teshima
- Laboratory of Veterinary Internal Medicine, School of Veterinary Medicine, Faculty of Veterinary Science, Nippon Veterinary and Life Science University, 1-7-1 Kyonan-cho, Musashino-shi, Tokyo, 180-8602, Japan
| | - Hirotaka Matsumoto
- Laboratory of Veterinary Internal Medicine, School of Veterinary Medicine, Faculty of Veterinary Science, Nippon Veterinary and Life Science University, 1-7-1 Kyonan-cho, Musashino-shi, Tokyo, 180-8602, Japan
| | - Hidekazu Koyama
- Laboratory of Veterinary Internal Medicine, School of Veterinary Medicine, Faculty of Veterinary Science, Nippon Veterinary and Life Science University, 1-7-1 Kyonan-cho, Musashino-shi, Tokyo, 180-8602, Japan
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11
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Yuchi Y, Suzuki R, Higuchi R, Saito T, Teshima T, Matsumoto H, Koyama H. Utility of Real-Time Three-Dimensional Echocardiography for the Assessment of Right Ventricular Morphology and Function in Large Animal Models. J Clin Med 2022; 11:jcm11072001. [PMID: 35407609 PMCID: PMC9000076 DOI: 10.3390/jcm11072001] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Revised: 03/29/2022] [Accepted: 04/01/2022] [Indexed: 02/04/2023] Open
Abstract
Real-time three-dimensional echocardiography (RT3DE) enables a noninvasive assessment of right ventricular (RV) morphology. However, no study has evaluated the relationship between RV function obtained by RT3DE and RV pressure-volume loops. This hypothesis-driven, experimental study aimed to assess the utility of RT3DE in the evaluation of RV morphology and function. Ten anesthetized beagle dogs sequentially underwent dobutamine infusion, acute infusion of lactated Ringer’s solution, and furosemide administration to alter RV contractility and loading conditions. RV pressure-volume loop-derived hemodynamic measurements and echocardiography, including two-dimensional speckle-tracking echocardiography and RT3DE, were performed in each study protocol. Bland−Altman analysis showed strong agreement in RV volume, ejection fraction, and stroke volume obtained by right heart catheterization and RT3DE. Multiple regression analyses revealed that the peak myocardial velocity of the lateral tricuspid annulus (RV s’) and global RV longitudinal strain rate were significantly associated with end-systolic elastance (adjusted r2 = 0.66, p < 0.001). RV s’, RV free wall longitudinal strain, and RT3DE-derived stroke volume/end-systolic RV volume ratio were associated with RV pressure-volume loops-derived end-systolic/arterial elastance ratio (adjusted r2 = 0.34, p < 0.001). RT3DE could detect the changes in catheterization-derived RV volume with a strong agreement and might be useful in estimating RV-pulmonary arterial coupling.
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12
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Jeon YK, Kwon JW, Jang J, Choi SW, Woo J, Cho SH, Yu BI, Chun YS, Youm JB, Zhang YH, Kim SJ. Lower troponin expression in the right ventricle of rats explains interventricular differences in E-C coupling. J Gen Physiol 2022; 154:212990. [PMID: 35099502 PMCID: PMC8823606 DOI: 10.1085/jgp.202112949] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Accepted: 01/06/2022] [Indexed: 12/12/2022] Open
Abstract
Despite distinctive functional and anatomic differences, a precise understanding of the cardiac interventricular differences in excitation–contraction (E–C) coupling mechanisms is still lacking. Here, we directly compared rat right and left cardiomyocytes (RVCM and LVCM). Whole-cell patch clamp, the IonOptix system, and fura-2 fluorimetry were used to measure electrical properties (action potential and ionic currents), single-cell contractility, and cytosolic Ca2+ ([Ca2+]i), respectively. Myofilament proteins were analyzed by immunoblotting. RVCM showed significantly shorter action potential duration (APD) and higher density of transient outward K+ current (Ito). However, the triggered [Ca2+]i change (Ca2+ transient) was not different, while the decay rate of the Ca2+ transient was slower in RVCM. Although the relaxation speed was also slower, the sarcomere shortening amplitude (ΔSL) was smaller in RVCM. SERCA activity was ∼60% lower in RVCM, which is partly responsible for the slower decay of the Ca2+ transient. Immunoblot analysis revealed lower expression of the cardiac troponin complex (cTn) in RVCM, implying a smaller Ca2+ buffering capacity (κS), which was proved by in situ analysis. The introduction of these new levels of cTn, Ito, and SERCA into a mathematical model of rat LVCM reproduced the similar Ca2+ transient, slower Ca2+ decay, shorter APD, and smaller ΔSL of RVCM. Taken together, these data show reduced expression of cTn proteins in the RVCM, which provides an explanation for the interventricular difference in the E–C coupling kinetics.
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Affiliation(s)
- Young Keul Jeon
- Department of Physiology, Ischemic/Hypoxic Disease Institute, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Jae Won Kwon
- Department of Physiology, Ischemic/Hypoxic Disease Institute, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Jihyun Jang
- Department of Physiology, Ischemic/Hypoxic Disease Institute, Seoul National University College of Medicine, Seoul, Republic of Korea.,Department of Surgery, Center for Vascular and Inflammatory Disease, University of Maryland School of Medicine, Baltimore, MD
| | - Seong Woo Choi
- Department of Physiology and Ion Channel Disease Research Center, Dongguk University College of Medicine, Seoul, Republic of Korea.,Ischemic/Hypoxic Disease Institute, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Joohan Woo
- Department of Physiology and Ion Channel Disease Research Center, Dongguk University College of Medicine, Seoul, Republic of Korea
| | - Su Han Cho
- Department of Physiology, Ischemic/Hypoxic Disease Institute, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Byeong Il Yu
- Department of Physiology, Ischemic/Hypoxic Disease Institute, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Yang Sook Chun
- Department of Physiology, Ischemic/Hypoxic Disease Institute, Seoul National University College of Medicine, Seoul, Republic of Korea.,Ischemic/Hypoxic Disease Institute, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Jae Boum Youm
- Cardiovascular and Metabolic Disease Center, Department of Physiology, College of Medicine, Inje University, Busan, Republic of Korea
| | - Yin Hua Zhang
- Department of Physiology, Ischemic/Hypoxic Disease Institute, Seoul National University College of Medicine, Seoul, Republic of Korea.,Yanbian University Hospital, Yanji, China.,Institute of Cardiovascular Sciences, Faculty of Biology, Medicine and Health Sciences, University of Manchester, Manchester, UK
| | - Sung Joon Kim
- Department of Physiology, Ischemic/Hypoxic Disease Institute, Seoul National University College of Medicine, Seoul, Republic of Korea.,Ischemic/Hypoxic Disease Institute, Seoul National University College of Medicine, Seoul, Republic of Korea.,Wide River Institute of Immunology, Seoul National University College of Medicine, Hongcheon, Republic of Korea
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13
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Monteiro DA, Lopes AG, Jejcic NU, da Silva Vasconcelos E, Kalinin AL, Rantin FT. Cardiac contractility of the African sharptooth catfish, Clarias gariepinus: role of extracellular Ca 2+, sarcoplasmic reticulum, and β-adrenergic stimulation. FISH PHYSIOLOGY AND BIOCHEMISTRY 2021; 47:1969-1982. [PMID: 34668117 DOI: 10.1007/s10695-021-01023-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Accepted: 10/07/2021] [Indexed: 06/13/2023]
Abstract
This study investigated the dependence of contraction from extracellular Ca2+, the presence of a functional sarcoplasmic reticulum (SR), and the effects of β-adrenergic stimulation using isometric cardiac muscle preparations. Moreover, the expression of Ca2+-handling proteins such as SR-Ca2+-ATPase (SERCA), phospholamban (PLN), and Na+/Ca2+ exchanger (NCX) were also evaluated in the ventricular tissue of adult African sharptooth catfish, Clarias gariepinus, a facultative air-breathing fish. In summary, we observed that (1) contractility was strongly regulated by extracellular Ca2+; (2) inhibition of SR Ca2+-release by application of ryanodine reduced steady-state force production; (3) ventricular myocardium exhibited clear post-rest decay, even in the presence of ryanodine, indicating a decrease in SR Ca2+ content and NCX as the main pathway for Ca2+ extrusion; (4) a positive force-frequency relationship was observed above 60 bpm (1.0 Hz); (5) ventricular tissue was responsive to β-adrenergic stimulation, which caused significant increases in twitch force, kept a linear force-frequency relationship from 12 to 96 bpm (0.2 to Hz), and improved the cardiac pumping capacity (CPC); and (6) African catfish myocardium exhibited similar expression patterns of NCX, SERCA, and PLN, corroborating our findings that both mechanisms for Ca2+ transport across the SR and sarcolemma contribute to Ca2+ activator. In conclusion, this fish species displays great physiological plasticity of E-C coupling, able to improve the ability to maintain cardiac performance under physiological conditions to ecological and/or adverse environmental conditions, such as hypoxic air-breathing activity.
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Affiliation(s)
- Diana Amaral Monteiro
- Department of Physiological Sciences, Federal University of São Carlos (UFSCar), Via Washington Luís km 235, 13565-905 São Carlos, São Paulo, Brazil.
| | - André Guelli Lopes
- Department of Physiological Sciences, Federal University of São Carlos (UFSCar), Via Washington Luís km 235, 13565-905 São Carlos, São Paulo, Brazil
- Joint Graduate Program in Physiological Sciences, Federal University of São Carlos - UFSCar/São Paulo State University, UNESP Campus Araraquara, São Paulo, Brazil
| | - Nathalia Usun Jejcic
- Department of Physiological Sciences, Federal University of São Carlos (UFSCar), Via Washington Luís km 235, 13565-905 São Carlos, São Paulo, Brazil
| | - Eliton da Silva Vasconcelos
- Department of Physiological Sciences, Federal University of São Carlos (UFSCar), Via Washington Luís km 235, 13565-905 São Carlos, São Paulo, Brazil
- Joint Graduate Program in Physiological Sciences, Federal University of São Carlos - UFSCar/São Paulo State University, UNESP Campus Araraquara, São Paulo, Brazil
| | - Ana Lúcia Kalinin
- Department of Physiological Sciences, Federal University of São Carlos (UFSCar), Via Washington Luís km 235, 13565-905 São Carlos, São Paulo, Brazil
| | - Francisco Tadeu Rantin
- Department of Physiological Sciences, Federal University of São Carlos (UFSCar), Via Washington Luís km 235, 13565-905 São Carlos, São Paulo, Brazil
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14
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Syomin F, Osepyan A, Tsaturyan A. Computationally efficient model of myocardial electromechanics for multiscale simulations. PLoS One 2021; 16:e0255027. [PMID: 34293046 PMCID: PMC8297763 DOI: 10.1371/journal.pone.0255027] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Accepted: 07/08/2021] [Indexed: 11/19/2022] Open
Abstract
A model of myocardial electromechanics is suggested. It combines modified and simplified versions of previously published models of cardiac electrophysiology, excitation-contraction coupling, and mechanics. The mechano-calcium and mechano-electrical feedbacks, including the strain-dependence of the propagation velocity of the action potential, are also accounted for. The model reproduces changes in the twitch amplitude and Ca2+-transients upon changes in muscle strain including the slow response. The model also reproduces the Bowditch effect and changes in the twitch amplitude and duration upon changes in the interstimulus interval, including accelerated relaxation at high stimulation frequency. Special efforts were taken to reduce the stiffness of the differential equations of the model. As a result, the equations can be integrated numerically with a relatively high time step making the model suitable for multiscale simulation of the human heart and allowing one to study the impact of myocardial mechanics on arrhythmias.
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Affiliation(s)
- Fyodor Syomin
- Institute of Mechanics, Lomonosov Moscow State University, Moscow, Russia
- * E-mail:
| | - Anna Osepyan
- Institute of Mechanics, Lomonosov Moscow State University, Moscow, Russia
| | - Andrey Tsaturyan
- Institute of Mechanics, Lomonosov Moscow State University, Moscow, Russia
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15
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Ince ME, Turgut K, Naseri A. Echocardiographic Assessment of Left Ventricular Systolic and Diastolic Functions in Dogs with Severe Sepsis and Septic Shock; Longitudinal Study. Animals (Basel) 2021; 11:ani11072011. [PMID: 34359139 PMCID: PMC8300373 DOI: 10.3390/ani11072011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Revised: 06/23/2021] [Accepted: 07/01/2021] [Indexed: 11/16/2022] Open
Abstract
Simple Summary Sepsis is associated with cardiovascular changes. The aim of the study was to determine sepsis-induced myocardial dysfunction in dogs with severe sepsis and septic shock using transthoracic echocardiography. Clinical, laboratory and cardiologic examinations for the septic dogs were performed at admission, 6 and 24 h, and on the day of discharge from the hospital. Left ventricular (LV) systolic dysfunction, LV diastolic dysfunction, and both types of the dysfunction were present in 13%, 70%, and 9% of dogs with sepsis, respectively. Dogs with LV diastolic dysfunction had a worse outcome and short-term mortality. Transthoracic echocardiography can be used for monitoring cardiovascular dysfunction in dogs with sepsis. Abstract The purpose of this study was to monitor left ventricular systolic dysfunction (LVSD) and diastolic dysfunction (LVDD) using transthoracic echocardiography (TTE) in dogs with severe sepsis and septic shock (SS/SS). A prospective longitudinal study using 23 dogs with SS/SS (experimental group) and 20 healthy dogs (control group) were carried out. All the clinical, laboratory and cardiologic examinations for the experimental dogs were performed at admission, 6 and 24 h after the start of treatment and on the day of discharge. LVSD was described as LV ejection fraction (LVEF) < 50%. LVDD was determined when the septal mitral annulus early diastolic velocity (LVEm) was <8 cm/s. LVSD and LVDD were present in 3 and 16 dogs with SS/SS, respectively, with both types of dysfunction present in 2 of the dogs. Although all the dogs with LVSD survived, 8 dogs with LVDD did not. The survival period was significantly shorter in dogs with an LVEm < 8 cm/s (1.3 ± 1.4 days). In conclusion, LVDD, rather than LVSD, was a common cardiovascular abnormality in the septic dogs, and this may be a negative prognostic factor. TTE is a useful tool for the identifying and monitoring of myocardial dysfunction in the dogs with SS/SS.
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Affiliation(s)
- Mehmet Ege Ince
- Department of Internal Medicine, Faculty of Veterinary Medicine, Near East University, 99100 Nicosia, North Cyprus, Turkey;
- Correspondence: or ; Tel.: +90-533-822-92-50
| | - Kursad Turgut
- Department of Internal Medicine, Faculty of Veterinary Medicine, Near East University, 99100 Nicosia, North Cyprus, Turkey;
| | - Amir Naseri
- Department of Internal Medicine, Faculty of Veterinary Medicine, Selcuk University, 42130 Konya, Turkey;
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16
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Mashali MA, Saad NS, Canan BD, Elnakish MT, Milani-Nejad N, Chung JH, Schultz EJ, Kiduko SA, Huang AW, Hare AN, Peczkowski KK, Fazlollahi F, Martin BL, Murray JD, Campbell CM, Kilic A, Whitson BA, Mokadam NA, Mohler PJ, Janssen PML. Impact of etiology on force and kinetics of left ventricular end-stage failing human myocardium. J Mol Cell Cardiol 2021; 156:7-19. [PMID: 33766524 PMCID: PMC8217133 DOI: 10.1016/j.yjmcc.2021.03.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Revised: 03/18/2021] [Accepted: 03/18/2021] [Indexed: 12/16/2022]
Abstract
BACKGROUND Heart failure (HF) is associated with highly significant morbidity, mortality, and health care costs. Despite the significant advances in therapies and prevention, HF remains associated with poor clinical outcomes. Understanding the contractile force and kinetic changes at the level of cardiac muscle during end-stage HF in consideration of underlying etiology would be beneficial in developing targeted therapies that can help improve cardiac performance. OBJECTIVE Investigate the impact of the primary etiology of HF (ischemic or non-ischemic) on left ventricular (LV) human myocardium force and kinetics of contraction and relaxation under near-physiological conditions. METHODS AND RESULTS Contractile and kinetic parameters were assessed in LV intact trabeculae isolated from control non-failing (NF; n = 58) and end-stage failing ischemic (FI; n = 16) and non-ischemic (FNI; n = 38) human myocardium under baseline conditions, length-dependent activation, frequency-dependent activation, and response to the β-adrenergic stimulation. At baseline, there were no significant differences in contractile force between the three groups; however, kinetics were impaired in failing myocardium with significant slowing down of relaxation kinetics in FNI compared to NF myocardium. Length-dependent activation was preserved and virtually identical in all groups. Frequency-dependent activation was clearly seen in NF myocardium (positive force frequency relationship [FFR]), while significantly impaired in both FI and FNI myocardium (negative FFR). Likewise, β-adrenergic regulation of contraction was significantly impaired in both HF groups. CONCLUSIONS End-stage failing myocardium exhibited impaired kinetics under baseline conditions as well as with the three contractile regulatory mechanisms. The pattern of these kinetic impairments in relation to NF myocardium was mainly impacted by etiology with a marked slowing down of kinetics in FNI myocardium. These findings suggest that not only force development, but also kinetics should be considered as a therapeutic target for improving cardiac performance and thus treatment of HF.
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Affiliation(s)
- Mohammed A Mashali
- Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, United States; Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, United States; Department of Surgery, Faculty of Veterinary Medicine, Damanhour University, Damanhour, Egypt
| | - Nancy S Saad
- Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, United States; Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, United States; Department of Pharmacology and Toxicology, Faculty of Pharmacy, Helwan University, Cairo, Egypt
| | - Benjamin D Canan
- Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, United States; Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, United States
| | - Mohammad T Elnakish
- Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, United States; Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, United States; Department of Pharmacology and Toxicology, Faculty of Pharmacy, Helwan University, Cairo, Egypt
| | - Nima Milani-Nejad
- Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, United States; Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, United States
| | - Jae-Hoon Chung
- Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, United States; Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, United States
| | - Eric J Schultz
- Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, United States; Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, United States
| | - Salome A Kiduko
- Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, United States; Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, United States
| | - Amanda W Huang
- Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, United States; Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, United States
| | - Austin N Hare
- Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, United States; Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, United States
| | - Kyra K Peczkowski
- Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, United States; Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, United States
| | - Farbod Fazlollahi
- Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, United States; Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, United States
| | - Brit L Martin
- Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, United States; Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, United States
| | - Jason D Murray
- Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, United States; Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, United States
| | - Courtney M Campbell
- Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, United States; Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, United States; Department of Internal Medicine, College of Medicine, The Ohio State University, Columbus, OH, United States
| | - Ahmet Kilic
- Division of Cardiac Surgery, College of Medicine, The Ohio State University, Columbus, OH, United States
| | - Bryan A Whitson
- Division of Cardiac Surgery, College of Medicine, The Ohio State University, Columbus, OH, United States
| | - Nahush A Mokadam
- Division of Cardiac Surgery, College of Medicine, The Ohio State University, Columbus, OH, United States
| | - Peter J Mohler
- Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, United States; Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, United States; Department of Internal Medicine, College of Medicine, The Ohio State University, Columbus, OH, United States
| | - Paul M L Janssen
- Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, United States; Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, United States; Department of Internal Medicine, College of Medicine, The Ohio State University, Columbus, OH, United States.
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17
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Fazlollahi F, Santini Gonzalez JJ, Repas SJ, Canan BD, Billman GE, Janssen PML. Contraction-relaxation coupling is unaltered by exercise training and infarction in isolated canine myocardium. J Gen Physiol 2021; 153:211978. [PMID: 33847735 PMCID: PMC8047736 DOI: 10.1085/jgp.202012829] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Revised: 02/20/2021] [Accepted: 03/18/2021] [Indexed: 12/28/2022] Open
Abstract
The two main phases of the mammalian cardiac cycle are contraction and relaxation; however, whether there is a connection between them in humans is not well understood. Routine exercise has been shown to improve cardiac function, morphology, and molecular signatures. Likewise, the acute and chronic changes that occur in the heart in response to injury, disease, and stress are well characterized, albeit not fully understood. In this study, we investigated how exercise and myocardial injury affect contraction–relaxation coupling. We retrospectively analyzed the correlation between the maximal speed of contraction and the maximal speed of relaxation of canine myocardium after receiving surgically induced myocardial infarction, followed by either sedentary recovery or exercise training for 10–12 wk. We used isolated right ventricular trabeculae, which were electrically paced at different lengths, frequencies, and with increasing β-adrenoceptor stimulation. In all conditions, contraction and relaxation were linearly correlated, irrespective of injury or training history. Based on these results and the available literature, we posit that contraction–relaxation coupling is a fundamental myocardial property that resides in the structural arrangement of proteins at the level of the sarcomere and that this may be regulated by the actions of cardiac myosin binding protein C (cMyBP-C) on actin and myosin.
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Affiliation(s)
- Farbod Fazlollahi
- Department of Physiology and Cell Biology, College of Medicine, Ohio State University, Columbus, OH
| | - Jorge J Santini Gonzalez
- Department of Physiology and Cell Biology, College of Medicine, Ohio State University, Columbus, OH
| | - Steven J Repas
- Department of Physiology and Cell Biology, College of Medicine, Ohio State University, Columbus, OH
| | - Benjamin D Canan
- Department of Physiology and Cell Biology, College of Medicine, Ohio State University, Columbus, OH
| | - George E Billman
- Department of Physiology and Cell Biology, College of Medicine, Ohio State University, Columbus, OH
| | - Paul M L Janssen
- Department of Physiology and Cell Biology, College of Medicine, Ohio State University, Columbus, OH
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18
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Jokerst S, Nizmutdinov D, Edgar C, Kaspick AM, Tong CW, Dostal DE. Preparation of Neonatal Rat Papillary Muscles for Contractile Studies. Methods Mol Biol 2021; 2319:31-44. [PMID: 34331240 DOI: 10.1007/978-1-0716-1480-8_4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Isolated cardiac tissue allows investigators to study mechanisms underlying normal and pathological conditions, which would otherwise be difficult or impossible to perform in vivo. In contrast to ventricular muscle strip preparations, papillary muscles can be prepared without severely damaging the muscle tissue. In this preparation, the isolated papillary muscle is fixed in an environmentally controlled organ bath chamber and electrically stimulated. The evoked twitch force is recorded using a pressure transducer, and parameters such as twitch force amplitude and twitch kinetics are analyzed. A variety of experimental protocols can be performed to investigate the calcium- and frequency-dependent contractility as well as dose-response curves of contractile agents, as well as simulation of pathologic conditions such as acute cardiac ischemia. Mouse papillary muscle preparations have long been the mainstay for studying interactions between intracellular calcium regulation and contractile responses under a number of simulated pathophysiological conditions. These studies are often used to complement in vitro studies performed using isolated neonatal rat cardiac myocytes. In this procedure, we describe how neonatal rat papillary muscles can also be prepared for use in contractile studies.
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Affiliation(s)
- Steven Jokerst
- Department of Medical Physiology, College of Medicine, Texas A&M University, Bryan, TX, USA
| | - Damir Nizmutdinov
- Department of Medical Physiology, College of Medicine, Texas A&M University, Bryan, TX, USA
| | - Charley Edgar
- Department of Medical Physiology, College of Medicine, Texas A&M University, Bryan, TX, USA
| | - April M Kaspick
- Department of Medical Physiology, College of Medicine, Texas A&M University, Bryan, TX, USA
| | - Carl W Tong
- Department of Medical Physiology, College of Medicine, Texas A&M University, Bryan, TX, USA
| | - David E Dostal
- Department of Medical Physiology, College of Medicine, Texas A&M University, Bryan, TX, USA.
- Central Texas Veterans Health Care System, Department of Internal Medicine, Dell Medical School, The University of Texas at Austin, Austin, TX, USA.
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19
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Species differences in cardiovascular physiology that affect pharmacology and toxicology. CURRENT OPINION IN TOXICOLOGY 2020. [DOI: 10.1016/j.cotox.2020.07.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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20
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Lyon A, Dupuis LJ, Arts T, Crijns HJGM, Prinzen FW, Delhaas T, Heijman J, Lumens J. Differentiating the effects of β-adrenergic stimulation and stretch on calcium and force dynamics using a novel electromechanical cardiomyocyte model. Am J Physiol Heart Circ Physiol 2020; 319:H519-H530. [PMID: 32734816 DOI: 10.1152/ajpheart.00275.2020] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Cardiac electrophysiology and mechanics are strongly interconnected. Calcium is crucial in this complex interplay through its role in cellular electrophysiology and sarcomere contraction. We aim to differentiate the effects of acute β-adrenergic stimulation (β-ARS) and cardiomyocyte stretch (increased sarcomere length) on calcium-transient dynamics and force generation, using a novel computational model of cardiac electromechanics. We implemented a bidirectional coupling between the O'Hara-Rudy model of human ventricular electrophysiology and the MechChem model of sarcomere mechanics through the buffering of calcium by troponin. The coupled model was validated using experimental data from large mammals or human samples. Calcium transient and force were simulated for various degrees of β-ARS and initial sarcomere lengths. The model reproduced force-frequency, quick-release, and isotonic contraction experiments, validating the bidirectional electromechanical interactions. An increase in β-ARS increased the amplitudes of force (augmented inotropy) and calcium transient, and shortened both force and calcium-transient duration (lusitropy). An increase in sarcomere length increased force amplitude even more, but decreased calcium-transient amplitude and increased both force and calcium-transient duration. Finally, a gradient in relaxation along the thin filament may explain the nonmonotonic decay in cytosolic calcium observed with high tension. Using a novel coupled human electromechanical model, we identified differential effects of β-ARS and stretch on calcium and force. Stretch mostly contributed to increased force amplitude and β-ARS to the reduction of calcium and force duration. We showed that their combination, rather than individual contributions, is key to ensure force generation, rapid relaxation, and low diastolic calcium levels.NEW & NOTEWORTHY This work identifies the contribution of electrical and mechanical alterations to regulation of calcium and force under exercise-like conditions using a novel human electromechanical model integrating ventricular electrophysiology and sarcomere mechanics. By better understanding their individual and combined effects, this can uncover arrhythmogenic mechanisms in exercise-like situations. This publicly available model is a crucial step toward understanding the complex interplay between cardiac electrophysiology and mechanics to improve arrhythmia risk prediction and treatment.
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Affiliation(s)
- Aurore Lyon
- Department of Biomedical Engineering, Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, The Netherlands
| | - Lauren J Dupuis
- Department of Biomedical Engineering, Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, The Netherlands.,Department of Bioinformatics-BiGCaT, School of Nutrition and Translational Research in Metabolism, Maastricht University, Maastricht, The Netherlands
| | - Theo Arts
- Department of Biomedical Engineering, Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, The Netherlands
| | - Harry J G M Crijns
- Department of Cardiology, Cardiovascular Research Institute Maastricht, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Frits W Prinzen
- Department of Physiology, Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, The Netherlands
| | - Tammo Delhaas
- Department of Biomedical Engineering, Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, The Netherlands
| | - Jordi Heijman
- Department of Cardiology, Cardiovascular Research Institute Maastricht, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Joost Lumens
- Department of Biomedical Engineering, Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, The Netherlands
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21
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Chen MP, Kiduko SA, Saad NS, Canan BD, Kilic A, Mohler PJ, Janssen PML. Stretching single titin molecules from failing human hearts reveals titin's role in blunting cardiac kinetic reserve. Cardiovasc Res 2020; 116:127-137. [PMID: 30778519 DOI: 10.1093/cvr/cvz043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2018] [Revised: 11/08/2018] [Accepted: 02/13/2019] [Indexed: 11/15/2022] Open
Abstract
AIMS Heart failure (HF) patients commonly experience symptoms primarily during elevated heart rates, as a result of physical activities or stress. A main determinant of diastolic passive tension, the elastic sarcomeric protein titin, has been shown to be associated with HF, with unresolved involvement regarding its role at different heart rates. To determine whether titin is playing a role in the heart rate (frequency-) dependent acceleration of relaxation (FDAR). W, we studied the FDAR responses in live human left ventricular cardiomyocytes and the corresponding titin-based passive tension (TPT) from failing and non-failing human hearts. METHODS AND RESULTS Using atomic force, we developed a novel single-molecule force spectroscopy approach to detect TPT based on the frequency-modulated cardiac cycle. Mean TPT reduced upon an increased heart rate in non-failing human hearts, while this reduction was significantly blunted in failing human hearts. These mechanical changes in the titin distal Ig domain significantly correlated with the frequency-dependent relaxation kinetics of human cardiomyocytes obtained from the corresponding hearts. Furthermore, the data suggested that the higher the TPT, the faster the cardiomyocytes relaxed, but the lower the potential of myocytes to speed up relaxation at a higher heart rate. Such poorer FDAR response was also associated with a lesser reduction or a bigger increase in TPT upon elevated heart rate. CONCLUSIONS Our study established a novel approach in detecting dynamic heart rate relevant tension changes physiologically on native titin domains. Using this approach, the data suggested that the regulation of kinetic reserve in cardiac relaxation and its pathological changes were associated with the intensity and dynamic changes of passive tension by titin.
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Affiliation(s)
- Mei-Pian Chen
- Department of Physiology and Cell Biology, The Ohio State University, Hamilton Hall 207a, 1645 Neil Avenue, Columbus, OH 43210, USA.,Dorothy M. Davis Heart and Lung Research Institute, 473 W 12th Ave, Columbus, OH 43210 USA
| | - Salome A Kiduko
- Department of Physiology and Cell Biology, The Ohio State University, Hamilton Hall 207a, 1645 Neil Avenue, Columbus, OH 43210, USA.,Dorothy M. Davis Heart and Lung Research Institute, 473 W 12th Ave, Columbus, OH 43210 USA
| | - Nancy S Saad
- Department of Physiology and Cell Biology, The Ohio State University, Hamilton Hall 207a, 1645 Neil Avenue, Columbus, OH 43210, USA.,Dorothy M. Davis Heart and Lung Research Institute, 473 W 12th Ave, Columbus, OH 43210 USA.,Department of Pharmacology and Toxicology, Faculty of Pharmacy, Helwan University, Cairo, Egypt
| | - Benjamin D Canan
- Department of Physiology and Cell Biology, The Ohio State University, Hamilton Hall 207a, 1645 Neil Avenue, Columbus, OH 43210, USA.,Dorothy M. Davis Heart and Lung Research Institute, 473 W 12th Ave, Columbus, OH 43210 USA
| | - Ahmet Kilic
- Division of Cardiothoracic Surgery, Department of Surgery, The Ohio State University Wexner Medical Center, 410 W 10th Ave, Columbus, OH 43210, USA
| | - Peter J Mohler
- Department of Physiology and Cell Biology, The Ohio State University, Hamilton Hall 207a, 1645 Neil Avenue, Columbus, OH 43210, USA.,Dorothy M. Davis Heart and Lung Research Institute, 473 W 12th Ave, Columbus, OH 43210 USA.,Department of Internal Medicine, The Ohio State University Wexner Medical Center, 395 W 12th Ave, Columbus, OH 43210, USA
| | - Paul M L Janssen
- Department of Physiology and Cell Biology, The Ohio State University, Hamilton Hall 207a, 1645 Neil Avenue, Columbus, OH 43210, USA.,Dorothy M. Davis Heart and Lung Research Institute, 473 W 12th Ave, Columbus, OH 43210 USA.,Department of Internal Medicine, The Ohio State University Wexner Medical Center, 395 W 12th Ave, Columbus, OH 43210, USA
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22
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Two-variable nullcline analysis of ionic general equilibrium predicts calcium homeostasis in ventricular myocytes. PLoS Comput Biol 2020; 16:e1007572. [PMID: 32502205 PMCID: PMC7316341 DOI: 10.1371/journal.pcbi.1007572] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Revised: 06/25/2020] [Accepted: 05/05/2020] [Indexed: 01/16/2023] Open
Abstract
Ventricular contraction is roughly proportional to the amount of calcium released from the Sarcoplasmic Reticulum (SR) during systole. While it is rather straightforward to measure calcium levels and contractibility under different physiological conditions, the complexity of calcium handling during systole and diastole has made the prediction of its release at steady state impossible. Here we approach the problem analyzing the evolution of intracellular and extracellular calcium fluxes during a single beat which is away from homeostatic balance. Using an in-silico subcellular model of rabbit ventricular myocyte, we show that the high dimensional nonlinear problem of finding the steady state can be reduced to a two-variable general equilibrium condition where pre-systolic calcium level in the cytosol and in the SR must fulfill simultaneously two different equalities. This renders calcium homeostasis as a problem that can be studied in terms of its equilibrium structure, leading to precise predictions of steady state from single-beat measurements. We show how changes in ion channels modify the general equilibrium, as shocks would do in general equilibrium macroeconomic models. This allows us to predict when an enhanced entrance of calcium in the cell reduces its contractibility and explain why SERCA gene therapy, a change in calcium handling to treat heart failure, might fail to improve contraction even when it successfully increases SERCA expression. Cardiomyocytes, upon voltage excitation, release calcium, which leads to cell contraction. However, under some pathological conditions, calcium handling is impaired. Recently, SERCA gene therapy, whose aim is to improve Ca2+ sequestration by the Sarcoplasmic Reticulum (SR), has failed to improve the prognosis of patients with Heart Failure. This, together with recent counterintuitive results in calcium handling, has highlighted the need for a framework to understand calcium homeostasis across species and pathologies. We show here that the proper framework is a general equilibrium approach of two independent variables. The development of this framework allows us to find a possible mechanism for the failure of SERCA gene therapy even when it manages to increase Ca SERCA expression.
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23
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Lookin O, Butova X, Protsenko Y. The role of pacing rate in the modulation of mechano-induced immediate and delayed changes in the force and Ca-transient of cardiac muscle. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2020; 159:34-45. [PMID: 32450183 DOI: 10.1016/j.pbiomolbio.2020.05.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Revised: 03/11/2020] [Accepted: 05/11/2020] [Indexed: 12/21/2022]
Abstract
Myocardial function is tuned by dynamic changes in length and load via mechano-calcium feedback. This regulation may be significantly affected by heart rhythm. We evaluated the mechano-induced modulation of contractility and Ca-transient (CaT) in the rat myocardium subjected to twitch-by-twitch shortening-re-lengthening (↓-↑) trains of different lengths (N = 1 … 720 cycles) at low (1 Hz) and near-physiological (3.5 Hz) pacing rates. Force/CaT characteristics were evaluated in the first post-train isometric twitch (immediate effect) and during slow changes (delayed maximal elevation/decrease) and compared with those of the pre-train twitch. The immediate inotropic effect was positive for N = 30 … 720 and negative for N = 1 … 20, while the delayed effect was always positive. The immediate and delayed inotropic effects were significantly higher at 3.5-Hz vs 1-Hz (P < 0.05). The prominent inotropism was accompanied by much smaller changes in the CaT diastolic level/amplitude. The shortening-re-lengthening train induced oscillations of the slow change in force at 3.5-Hz (always) and at 1-Hz (∼50% of muscles), which were dependent of the train length and independent of the pacing rate. We suggest that twitch-by-twitch shortening-re-lengthening of cardiac muscle decreases Ca2+ buffering by troponin C and elevates Ca2+ loading of the sarcoplasmic reticulum (SR); the latter cumulatively depends on the train length. A high pacing rate intensifies the cumulative transient shift in the SR Ca2+ loading, augmenting the post-train inotropic response and prolonging its recovery to the pre-train level. The pacing-dependent mechano-induced inotropic effects remain to be elucidated in the myocardium with impaired Ca handling.
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Affiliation(s)
- Oleg Lookin
- Institute of Immunology and Physiology, Ural Branch of Russian Academy of Sciences, 620049, 106 Pervomayskaya St., Yekaterinburg, Russia; Center for Fundamental Biotechnology and Bioengineering, Institute of Natural Sciences and Mathematics, Ural Federal University, 620002, 19 Mira St., Yekaterinburg, Russia.
| | - Xenia Butova
- Institute of Immunology and Physiology, Ural Branch of Russian Academy of Sciences, 620049, 106 Pervomayskaya St., Yekaterinburg, Russia; Center for Fundamental Biotechnology and Bioengineering, Institute of Natural Sciences and Mathematics, Ural Federal University, 620002, 19 Mira St., Yekaterinburg, Russia
| | - Yuri Protsenko
- Institute of Immunology and Physiology, Ural Branch of Russian Academy of Sciences, 620049, 106 Pervomayskaya St., Yekaterinburg, Russia
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24
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Functional culture and in vitro genetic and small-molecule manipulation of adult mouse cardiomyocytes. Commun Biol 2020; 3:229. [PMID: 32393743 PMCID: PMC7214405 DOI: 10.1038/s42003-020-0946-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Accepted: 04/17/2020] [Indexed: 11/28/2022] Open
Abstract
Primary adult cardiomyocyte (aCM) represent the mature form of myocytes found in the adult heart. However, culture of aCMs in particular is challenged by poor survival and loss of phenotype, rendering extended in vitro experiments unfeasible. Here, we establish murine aCM culture methods that enhance survival and maintain sarcomeric structure and Ca2+ cycling to enable physiologically relevant contractile force measurements. We also demonstrate genetic and small-molecule manipulations that probe mechanisms underlying myocyte functional performance. Together, these refinements to aCM culture present a toolbox with which to advance our understanding of myocardial physiology. Callaghan et al. present a combinatory approach to culturing harvested adult mouse cardiomyocytes (aCMs). Under traditional culture protocols, aCMs rapidly lose their phenotype and undergo cell death. With their protocol, the authors show aCMs remain viable and retain their phenotype for 7 days, enough time to do genetic manipulation and small molecule screening.
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25
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Muir WW, Hamlin RL. Myocardial Contractility: Historical and Contemporary Considerations. Front Physiol 2020; 11:222. [PMID: 32296340 PMCID: PMC7137917 DOI: 10.3389/fphys.2020.00222] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Accepted: 02/26/2020] [Indexed: 12/17/2022] Open
Abstract
The term myocardial contractility is thought to have originated more than 125 years ago and has remained and enigma ever since. Although the term is frequently used in textbooks, editorials and contemporary manuscripts its definition remains illusive often being conflated with cardiac performance or inotropy. The absence of a universally accepted definition has led to confusion, disagreement and misconceptions among physiologists, cardiologists and safety pharmacologists regarding its definition particularly in light of new discoveries regarding the load dependent kinetics of cardiac contraction and their translation to cardiac force-velocity and ventricular pressure-volume measurements. Importantly, the Starling interpretation of force development is length-dependent while contractility is length independent. Most historical definitions employ an operational approach and define cardiac contractility in terms of the hearts mechanical properties independent of loading conditions. Literally defined the term contract infers that something has become smaller, shrunk or shortened. The addition of the suffix “ility” implies the quality of this process. The discovery and clinical investigation of small molecules that bind to sarcomeric proteins independently altering force or velocity requires that a modern definition of the term myocardial contractility be developed if the term is to persist. This review reconsiders the historical and contemporary interpretations of the terms cardiac performance and inotropy and recommends a modern definition of myocardial contractility as the preload, afterload and length-independent intrinsic kinetically controlled, chemo-mechanical processes responsible for the development of force and velocity.
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Affiliation(s)
- William W Muir
- College of Veterinary Medicine, Lincoln Memorial University, Harrogate, TN, United States
| | - Robert L Hamlin
- College of Veterinary Medicine, The Ohio State University, Columbus, OH, United States
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26
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Abu-Khousa M, Fiegle DJ, Sommer ST, Minabari G, Milting H, Heim C, Weyand M, Tomasi R, Dendorfer A, Volk T, Seidel T. The Degree of t-System Remodeling Predicts Negative Force-Frequency Relationship and Prolonged Relaxation Time in Failing Human Myocardium. Front Physiol 2020; 11:182. [PMID: 32231589 PMCID: PMC7083140 DOI: 10.3389/fphys.2020.00182] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Accepted: 02/17/2020] [Indexed: 01/28/2023] Open
Abstract
The normally positive cardiac force-frequency relationship (FFR) becomes flat or negative in chronic heart failure (HF). Here we explored if remodeling of the cardiomyocyte transverse tubular system (t-system) is associated with alterations in FFR and contractile kinetics in failing human myocardium. Left-ventricular myocardial slices from 13 failing human hearts were mounted into a biomimetic culture setup. Maximum twitch force (F), 90% contraction duration (CD90), time to peak force (TTP) and time to relaxation (TTR) were determined at 37°C and 0.2–2 Hz pacing frequency. F1Hz/F0.5Hz and F2Hz/F0.5Hz served as measures of FFR, intracellular cardiomyocyte t-tubule distance (ΔTT) as measure of t-system remodeling. Protein levels of SERCA2, NCX1, and PLB were quantified by immunoblotting. F1Hz/F0.5Hz (R2 = 0.82) and F2Hz/F0.5Hz (R2 = 0.5) correlated negatively with ΔTT, i.e., samples with severe t-system loss exhibited a negative FFR and reduced myocardial wall tension at high pacing rates. PLB levels also predicted F1Hz/F0.5Hz, but to a lesser degree (R2 = 0.49), whereas NCX1 was not correlated (R2 = 0.02). CD90 correlated positively with ΔTT (R2 = 0.39) and negatively with SERCA2/PLB (R2 = 0.42), indicating that both the t-system and SERCA activity are important for contraction kinetics. Surprisingly, ΔTT was not associated with TTP (R2 = 0) but rather with TTR (R2 = 0.5). This became even more pronounced when interaction with NCX1 expression was added to the model (R2 = 0.79), suggesting that t-system loss impairs myocardial relaxation especially when NCX1 expression is low. The degree of t-system remodeling predicts FFR inversion and contraction slowing in failing human myocardium. Moreover, together with NCX, the t-system may be important for myocardial relaxation.
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Affiliation(s)
- Maha Abu-Khousa
- Institute of Cellular and Molecular Physiology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Dominik J Fiegle
- Institute of Cellular and Molecular Physiology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Sophie T Sommer
- Institute of Cellular and Molecular Physiology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Ghazali Minabari
- Department of Cardiac Surgery, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Hendrik Milting
- Erich and Hanna Klessmann Institute, Clinic for Thoracic and Cardiovascular Surgery, Heart and Diabetes Center NRW, Ruhr University Bochum, Bad Oeynhausen, Germany
| | - Christian Heim
- Department of Cardiac Surgery, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Michael Weyand
- Department of Cardiac Surgery, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany.,Muscle Research Center Erlangen (MURCE), Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Roland Tomasi
- Walter Brendel Centre of Experimental Medicine, University Hospital, LMU Munich, Munich, Germany.,Department of Anaesthesiology, University Hospital, LMU Munich, Munich, Germany
| | - Andreas Dendorfer
- Walter Brendel Centre of Experimental Medicine, University Hospital, LMU Munich, Munich, Germany.,German Center for Cardiovascular Research (DZHK), Partner Site Munich Heart Alliance, Munich, Germany
| | - Tilmann Volk
- Institute of Cellular and Molecular Physiology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany.,Muscle Research Center Erlangen (MURCE), Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Thomas Seidel
- Institute of Cellular and Molecular Physiology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany.,Muscle Research Center Erlangen (MURCE), Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
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27
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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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28
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Monge García MI, Del Rio Lechuga A, Fletcher N, Gil Cano A. Increased atrial contraction contribution to left ventricular filling during early septic shock. J Crit Care 2019; 54:220-227. [PMID: 31630070 DOI: 10.1016/j.jcrc.2019.09.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Revised: 08/07/2019] [Accepted: 09/10/2019] [Indexed: 01/05/2023]
Abstract
PURPOSE To assess the atrial systolic function and the contribution of atrial contraction to left ventricular (LV) filling in septic shock patients as compared with healthy volunteers. METHODS Twenty-seven septic patients evaluated during first 48 h of ICU admission and compared with 27 healthy volunteers. Left atrial (LA) contraction contribution to LV filling was calculated as the active emptying atrial volume/LV end-diastolic volume. Atrial systolic function was evaluated with the atrial kinetic force [LAKE = 0.5 × blood density × LVVactive × (peak A velocity)2] and atrial ejection force [LASF = 0.5 × blood density × mitral annulus area × (peak A velocity)2]. RESULTS LV ejection fraction was lower in septic patients than in control group: 51 ± 14%vs 60 ± 6% (p < 0.01). Contribution of LA contraction to LV preload was greater in septic patients than in normal subjects (26.7 ± 11.3% vs 15.9 ± 5.9%, p < 0.001), even if adjusted for age (0.49 ± 0.19 vs 0.35 ± 0.13, p = 0.004). LAKE and LASF were also significantly larger in septic patients than in normal subjects (21.8 ± 9.1 vs 7.3 ± 3 kdynes·cm, p < 0.001; 16.1 ± 11.7 vs 9.8 ± 4.3 kdynes, p = 0.048, respectively), and remained unchanged during the next 48 h. CONCLUSION In septic shock patients, LA systolic function increased and greatly contributed to support LV filling. These results highlight the role of preserving atrial contraction on the hemodynamic resuscitation in early septic shock.
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Affiliation(s)
- Manuel Ignacio Monge García
- Unidad de Cuidados Intensivos, Hospital Universitario SAS de Jerez, C/ Circunvalación s/n, 11408 Jerez de la Frontera, Spain.
| | - Ana Del Rio Lechuga
- Unidad de Gestión Clínica de Cardiología, Hospital Universitario SAS de Jerez, C/ Circunvalación s/n, 11408 Jerez de la Frontera, Spain.
| | - Nick Fletcher
- Department of Anesthesia and Critical Care, St Georges University Hospitals NHS Trust, Blackshaw Road, SW17 0QT London, UK.
| | - Anselmo Gil Cano
- Unidad de Cuidados Intensivos, Hospital Universitario SAS de Jerez, C/ Circunvalación s/n, 11408 Jerez de la Frontera, Spain.
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29
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Ding Y, Lyons SA, Scott GR, Gillis TE. Characterizing the influence of chronic hypobaric hypoxia on diaphragmatic myofilament contractile function and phosphorylation in high-altitude deer mice and low-altitude white-footed mice. J Comp Physiol B 2019; 189:489-499. [PMID: 31278612 DOI: 10.1007/s00360-019-01224-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2019] [Revised: 06/06/2019] [Accepted: 06/24/2019] [Indexed: 11/27/2022]
Abstract
Deer mice, Peromyscusmaniculatus, live at high altitudes where limited O2 represents a challenge to maintaining oxygen delivery to tissues. Previous work has demonstrated that hypoxia acclimation of deer mice and low altitude white-footed mice (P. leucopus) increases the force generating capacity of the diaphragm. The mechanism behind this improved contractile function is not known. Within myocytes, the myofilament plays a critical role in setting the rate and level of force production, and its ability to generate force can change in response to changes in physiological conditions. In the current study, we examined how chronic hypobaric hypoxia exposure of deer mice and white-footed mice influences the Ca2+ activation of force generation by skinned diaphragmatic myofilaments, and the phosphorylation of myofilament proteins. Results demonstrate that myofilament force production, and the Ca2+ sensitivity of force generation, were not impacted by acclimation to hypobaric hypoxia, and did not differ between preparations from the two species. The cooperativity of the force-pCa relationship, and the maximal rate of force generation were also the same in the preparations from both species, and not impacted by acclimation. Finally, the relative phosphorylation of TnT, and MLC was lower in deer mice than white-footed mice, but was not affected by acclimation. These results indicate that species differences in diaphragm function, and the increase in force production with hypoxia acclimation, are not due to differences, or changes, in myofilament function. However, it appears that diaphragmatic myofilament function in these species is not affected by chronic hypobaric hypoxia exposure.
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Affiliation(s)
- Y Ding
- Department of Integrative Biology, University of Guelph, Guelph, ON, N1G-2W1, Canada
| | - S A Lyons
- Department of Biology, McMaster University, Hamilton, ON, Canada
| | - G R Scott
- Department of Biology, McMaster University, Hamilton, ON, Canada
| | - Todd E Gillis
- Department of Integrative Biology, University of Guelph, Guelph, ON, N1G-2W1, Canada.
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30
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Fernández-Miranda G, Romero-Garcia T, Barrera-Lechuga TP, Mercado-Morales M, Rueda A. Impaired Activity of Ryanodine Receptors Contributes to Calcium Mishandling in Cardiomyocytes of Metabolic Syndrome Rats. Front Physiol 2019; 10:520. [PMID: 31114513 PMCID: PMC6503767 DOI: 10.3389/fphys.2019.00520] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Accepted: 04/11/2019] [Indexed: 01/11/2023] Open
Abstract
Metabolic syndrome (MetS) has become a global epidemic. MetS is a serious health problem because of its related cardiovascular complications, which include hypertension and delayed heart rate recovery after exercise. The molecular bases of cardiac dysfunction in MetS are still under scrutiny and may be related to anomalies in the activity and expression of key proteins involved in the cardiac excitation-contraction coupling (ECC). The cardiac Ca2+ channel/ryanodine receptor (RyR2) participates in releasing Ca2+ from internal stores and plays a key role in the modulation of ECC. We examined alterations in expression, phosphorylation status, Ca2+ sensitivity, and in situ function (by measuring Ca2+ sparks and Ca2+ transients) of RyR2; alterations in these characteristics could help to explain the Ca2+ handling disturbances in MetS cardiomyocytes. MetS was induced in rats by adding commercially refined sugar (30% sucrose) to their drinking water for 24 weeks. Cardiomyocytes of MetS rats displayed decreased Ca2+ transient amplitude and cell contractility at all stimulation frequencies. Quiescent MetS cardiomyocytes showed a decrease in Ca2+ spark frequency, amplitude, and spark-mediated Ca2+ leak. The [3H]-ryanodine binding data showed that functionally active RyRs are significantly diminished in MetS heart microsomes; and exhibited rapid Ca2+-induced inactivation. The phosphorylation of corresponding Ser2814 (a preferential target for CaMKII) of the hRyR2 was significantly diminished. RyR2 protein expression and Ser2808 phosphorylation level were both unchanged. Further, we demonstrated that cardiomyocyte Ca2+ mishandling was associated with reduced SERCA pump activity due to decreased Thr17-PLN phosphorylation, suggesting a downregulation of CaMKII in MetS hearts, though the SR Ca2+ load remained unchanged. The reduction in the phosphorylation level of RyR2 at Ser2814 decreases RyR2 availability for activation during ECC. In conclusion, the impaired in situ activity of RyR2 may also account for the poor overall cardiac outcome reported in MetS patients; hence, the SERCA pump and RyR2 are both attractive potential targets for future therapies.
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Affiliation(s)
- Gaudencio Fernández-Miranda
- Departamento de Bioquímica, Centro de Investigación y de Estudios Avanzados del IPN (CINVESTAV), Mexico City, Mexico
| | - Tatiana Romero-Garcia
- Departamento de Bioquímica, Centro de Investigación y de Estudios Avanzados del IPN (CINVESTAV), Mexico City, Mexico
| | - Tarín P Barrera-Lechuga
- Departamento de Bioquímica, Centro de Investigación y de Estudios Avanzados del IPN (CINVESTAV), Mexico City, Mexico
| | - Martha Mercado-Morales
- Departamento de Bioquímica, Centro de Investigación y de Estudios Avanzados del IPN (CINVESTAV), Mexico City, Mexico
| | - Angélica Rueda
- Departamento de Bioquímica, Centro de Investigación y de Estudios Avanzados del IPN (CINVESTAV), Mexico City, Mexico
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31
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Sanfilippo F, Scolletta S, Morelli A, Vieillard-Baron A. Practical approach to diastolic dysfunction in light of the new guidelines and clinical applications in the operating room and in the intensive care. Ann Intensive Care 2018; 8:100. [PMID: 30374644 PMCID: PMC6206316 DOI: 10.1186/s13613-018-0447-x] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Accepted: 10/20/2018] [Indexed: 12/26/2022] Open
Abstract
There is growing evidence both in the perioperative period and in the field of intensive care (ICU) on the association between left ventricular diastolic dysfunction (LVDD) and worse outcomes in patients. The recent American Society of Echocardiography and European Association of Cardiovascular Imaging joint recommendations have tried to simplify the diagnosis and the grading of LVDD. However, both an often unknown pre-morbid LV diastolic function and the presence of several confounders-i.e., use of vasopressors, positive pressure ventilation, volume loading-make the proposed parameters difficult to interpret, especially in the ICU. Among the proposed parameters for diagnosis and grading of LVDD, the two tissue Doppler imaging-derived variables e' and E/e' seem most reliable. However, these are not devoid of limitations. In the present review, we aim at rationalizing the applicability of the recent recommendations to the perioperative and ICU areas, discussing the clinical meaning and echocardiographic findings of different grades of LVDD, describing the impact of LVDD on patients' outcomes and providing some hints on the management of patients with LVDD.
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Affiliation(s)
- F. Sanfilippo
- Department of Anesthesia and Intensive Care, IRCCS-ISMETT (Istituto Mediterraneo per i Trapianti e Terapie ad alta specializzazione), Palermo, Italy
| | - S. Scolletta
- Unit of Intensive Care Medicine, Department of Medical Biotechnologies, University of Siena, Siena, Italy
| | - A. Morelli
- Department of Anaesthesiology and Intensive Care, University of Rome, “La Sapienza”, Rome, Italy
| | - A. Vieillard-Baron
- Hospital Ambroise Paré, Assistance Publique-Hôpitaux de Paris, Boulogne, France
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32
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Sanfilippo F, Corredor C, Arcadipane A, Landesberg G, Vieillard-Baron A, Cecconi M, Fletcher N. Tissue Doppler assessment of diastolic function and relationship with mortality in critically ill septic patients: a systematic review and meta-analysis. Br J Anaesth 2017; 119:583-594. [DOI: 10.1093/bja/aex254] [Citation(s) in RCA: 92] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/29/2023] Open
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33
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Peverill RE, Chou B, Donelan L. Left ventricular long axis tissue Doppler systolic velocity is independently related to heart rate and body size. PLoS One 2017; 12:e0173383. [PMID: 28288162 PMCID: PMC5348126 DOI: 10.1371/journal.pone.0173383] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2016] [Accepted: 02/20/2017] [Indexed: 02/02/2023] Open
Abstract
Background The physiological factors which affect left ventricular (LV) long-axis function are not fully defined. We investigated the relationships of resting heart rate and body size with the peak velocities and amplitudes of LV systolic and early diastolic long axis motion, and also with long-axis contraction duration. Methods Two groups of adults free of cardiac disease underwent pulsed-wave tissue Doppler imaging at the septal and lateral mitral annular borders. Group 1 (n = 77) were healthy subjects <50 years of age and Group 2 (n = 65) were subjects between 40–80 years of age referred for stress echocardiography. Systolic excursion (SExc), duration (SDur) and peak velocity (s') and early diastolic excursion (EDExc) and peak velocity (e') were measured. Results SExc was not correlated with heart rate, height or body surface area (BSA) for either LV wall in either group, but SDur was inversely correlated with heart rate for both walls and both groups, and after adjustment for heart rate, males in both groups had a shorter septal SDur. Septal and lateral s` were independently and positively correlated with SExc, heart rate and height in both groups, independent of sex and age. There were no correlations of heart rate, height or BSA with either e` or EDExc for either wall in either group. Conclusion Heart rate and height independently modify the relationship between s` and SExc, but neither are related to EDExc or e`. These findings suggest that s` and SExc cannot be used interchangeably for the assessment of LV long-axis contraction.
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Affiliation(s)
- Roger E. Peverill
- Monash Cardiovascular Research Centre, MonashHeart and Department of Medicine (School of Clinical Sciences at Monash Medical Centre), Monash University and Monash Health, Clayton, Victoria, Australia
- * E-mail:
| | - Bon Chou
- Monash Cardiovascular Research Centre, MonashHeart and Department of Medicine (School of Clinical Sciences at Monash Medical Centre), Monash University and Monash Health, Clayton, Victoria, Australia
| | - Lesley Donelan
- Monash Cardiovascular Research Centre, MonashHeart and Department of Medicine (School of Clinical Sciences at Monash Medical Centre), Monash University and Monash Health, Clayton, Victoria, Australia
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34
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Milani-Nejad N, Schultz EJ, Slabaugh JL, Janssen PML, Rafael-Fortney JA. Myocardial Contractile Dysfunction Is Present without Histopathology in a Mouse Model of Limb-Girdle Muscular Dystrophy-2F and Is Prevented after Claudin-5 Virotherapy. Front Physiol 2016; 7:539. [PMID: 27999547 PMCID: PMC5138189 DOI: 10.3389/fphys.2016.00539] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2016] [Accepted: 10/27/2016] [Indexed: 01/18/2023] Open
Abstract
Mutations in several members of the dystrophin glycoprotein complex lead to skeletal and cardiomyopathies. Cardiac care for these muscular dystrophies consists of management of symptoms with standard heart medications after detection of reduced whole heart function. Recent evidence from both Duchenne muscular dystrophy patients and animal models suggests that myocardial dysfunction is present before myocardial damage or deficiencies in whole heart function, and that treatment prior to heart failure symptoms may be beneficial. To determine whether this same early myocardial dysfunction is present in other muscular dystrophy cardiomyopathies, we conducted a physiological assessment of cardiac function at the tissue level in the δ-sarcoglycan null mouse model (Sgcd−/−) of Limb-girdle muscular dystrophy type 2F. Baseline cardiac contractile force measurements using ex vivo intact linear muscle preparations, were severely depressed in these mice without the presence of histopathology. Virotherapy withclaudin-5 prevents the onset of cardiomyopathy in another muscular dystrophy model. After virotherapy with claudin-5, the cardiac contractile force deficits in Sgcd−/− mice are no longer significant. These studies suggest that screening Limb-girdle muscular dystrophy patients using methods that detect earlier functional changes may provide a longer therapeutic window for cardiac care.
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Affiliation(s)
- Nima Milani-Nejad
- Department of Physiology and Cell Biology, The Ohio State University Wexner Medical CenterColumbus, OH, USA; Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical CenterColumbus, OH, USA; Medical Scientist Training Program and Biomedical Sciences Graduate Program, The Ohio State University Wexner Medical CenterColumbus, OH, USA
| | - Eric J Schultz
- Department of Physiology and Cell Biology, The Ohio State University Wexner Medical CenterColumbus, OH, USA; Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical CenterColumbus, OH, USA; Department of Molecular and Cellular Biochemistry, The Ohio State University Wexner Medical CenterColumbus, OH, USA
| | - Jessica L Slabaugh
- Department of Physiology and Cell Biology, The Ohio State University Wexner Medical CenterColumbus, OH, USA; Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical CenterColumbus, OH, USA
| | - Paul M L Janssen
- Department of Physiology and Cell Biology, The Ohio State University Wexner Medical CenterColumbus, OH, USA; Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical CenterColumbus, OH, USA
| | - Jill A Rafael-Fortney
- Department of Physiology and Cell Biology, The Ohio State University Wexner Medical CenterColumbus, OH, USA; Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical CenterColumbus, OH, USA; Department of Molecular and Cellular Biochemistry, The Ohio State University Wexner Medical CenterColumbus, OH, USA
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35
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Canan BD, Haizlip KM, Xu Y, Monasky MM, Hiranandani N, Milani-Nejad N, Varian KD, Slabaugh JL, Schultz EJ, Fedorov VV, Billman GE, Janssen PML. Effect of exercise training and myocardial infarction on force development and contractile kinetics in isolated canine myocardium. J Appl Physiol (1985) 2016; 120:817-24. [PMID: 26823341 DOI: 10.1152/japplphysiol.00775.2015] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Accepted: 01/27/2016] [Indexed: 12/20/2022] Open
Abstract
It is well known that moderate exercise training elicits a small increase in ventricular mass (i.e., a physiological hypertrophy) that has many beneficial effects on overall cardiac health. It is also well known that, when a myocardial infarction damages part of the heart, the remaining myocardium remodels to compensate for the loss of viable functioning myocardium. The effects of exercise training, myocardial infarction (MI), and their interaction on the contractile performance of the myocardium itself remain largely to be determined. The present study investigated the contractile properties and kinetics of right ventricular myocardium isolated from sedentary and exercise trained (10-12 wk progressively increasing treadmill running, begun 4 wk after MI induction) dogs with and without a left ventricular myocardial infarction. Exercise training increased force development, whereas MI decreased force development that was not improved by exercise training. Contractile kinetics were significantly slower in the trained dogs, whereas this impact of training was less or no longer present after MI. Length-dependent activation, both evaluated on contractile force and kinetics, was similar in all four groups. The control exercise-trained group exhibited a more positive force-frequency relationship compared with the sedentary control group while both sedentary and trained post-MI dogs had a more negative relationship. Last, the impact of the β-adrenergic receptor agonist isoproterenol resulted in a similar increase in force and acceleration of contractile kinetics in all groups. Thus, exercise training increased developed force but slowed contractile kinetics in control (noninfarcted animals), actions that were attenuated or completely absent in post-MI dogs.
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Affiliation(s)
- Benjamin D Canan
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, Ohio; and
| | - Kaylan M Haizlip
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, Ohio; and
| | - Ying Xu
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, Ohio; and
| | - Michelle M Monasky
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, Ohio; and
| | - Nitisha Hiranandani
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, Ohio; and
| | - Nima Milani-Nejad
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, Ohio; and
| | - Kenneth D Varian
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, Ohio; and
| | - Jessica L Slabaugh
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, Ohio; and
| | - Eric J Schultz
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, Ohio; and
| | - Vadim V Fedorov
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, Ohio; and Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio
| | - George E Billman
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, Ohio; and Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio
| | - Paul M L Janssen
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, Ohio; and Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio
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36
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Sorrentino A, Signore S, Qanud K, Borghetti G, Meo M, Cannata A, Zhou Y, Wybieralska E, Luciani M, Kannappan R, Zhang E, Matsuda A, Webster A, Cimini M, Kertowidjojo E, D'Alessandro DA, Wunimenghe O, Michler RE, Royer C, Goichberg P, Leri A, Barrett EG, Anversa P, Hintze TH, Rota M. Myocyte repolarization modulates myocardial function in aging dogs. Am J Physiol Heart Circ Physiol 2016; 310:H873-90. [PMID: 26801307 DOI: 10.1152/ajpheart.00682.2015] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Accepted: 12/24/2015] [Indexed: 12/19/2022]
Abstract
Studies of myocardial aging are complex and the mechanisms involved in the deterioration of ventricular performance and decreased functional reserve of the old heart remain to be properly defined. We have studied a colony of beagle dogs from 3 to 14 yr of age kept under a highly regulated environment to define the effects of aging on the myocardium. Ventricular, myocardial, and myocyte function, together with anatomical and structural properties of the organ and cardiomyocytes, were evaluated. Ventricular hypertrophy was not observed with aging and the structural composition of the myocardium was modestly affected. Alterations in the myocyte compartment were identified in aged dogs, and these factors negatively interfere with the contractile reserve typical of the young heart. The duration of the action potential is prolonged in old cardiomyocytes contributing to the slower electrical recovery of the myocardium. Also, the remodeled repolarization of cardiomyocytes with aging provides inotropic support to the senescent muscle but compromises its contractile reserve, rendering the old heart ineffective under conditions of high hemodynamic demand. The defects in the electrical and mechanical properties of cardiomyocytes with aging suggest that this cell population is an important determinant of the cardiac senescent phenotype. Collectively, the delayed electrical repolarization of aging cardiomyocytes may be viewed as a critical variable of the aging myopathy and its propensity to evolve into ventricular decompensation under stressful conditions.
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Affiliation(s)
- Andrea Sorrentino
- Departments of Anesthesia and Medicine, and Division of Cardiovascular Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Sergio Signore
- Departments of Anesthesia and Medicine, and Division of Cardiovascular Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Khaled Qanud
- Department of Physiology, New York Medical College, Valhalla, New York
| | - Giulia Borghetti
- Departments of Anesthesia and Medicine, and Division of Cardiovascular Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Marianna Meo
- Departments of Anesthesia and Medicine, and Division of Cardiovascular Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Antonio Cannata
- Departments of Anesthesia and Medicine, and Division of Cardiovascular Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Yu Zhou
- Departments of Anesthesia and Medicine, and Division of Cardiovascular Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Ewa Wybieralska
- Departments of Anesthesia and Medicine, and Division of Cardiovascular Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Marco Luciani
- Departments of Anesthesia and Medicine, and Division of Cardiovascular Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Ramaswamy Kannappan
- Departments of Anesthesia and Medicine, and Division of Cardiovascular Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Eric Zhang
- Departments of Anesthesia and Medicine, and Division of Cardiovascular Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Alex Matsuda
- Departments of Anesthesia and Medicine, and Division of Cardiovascular Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Andrew Webster
- Departments of Anesthesia and Medicine, and Division of Cardiovascular Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Maria Cimini
- Departments of Anesthesia and Medicine, and Division of Cardiovascular Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts
| | | | | | - Oriyanhan Wunimenghe
- Department of Cardiovascular and Thoracic Surgery, Montefiore Medical Center, Albert Einstein College of Medicine, New York, New York; and
| | - Robert E Michler
- Department of Cardiovascular and Thoracic Surgery, Montefiore Medical Center, Albert Einstein College of Medicine, New York, New York; and
| | | | - Polina Goichberg
- Departments of Anesthesia and Medicine, and Division of Cardiovascular Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Annarosa Leri
- Departments of Anesthesia and Medicine, and Division of Cardiovascular Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Edward G Barrett
- Lovelace Respiratory Research Institute, Albuquerque, New Mexico
| | - Piero Anversa
- Departments of Anesthesia and Medicine, and Division of Cardiovascular Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Thomas H Hintze
- Department of Physiology, New York Medical College, Valhalla, New York
| | - Marcello Rota
- Departments of Anesthesia and Medicine, and Division of Cardiovascular Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts; Department of Physiology, New York Medical College, Valhalla, New York;
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Abstract
Heat stress increases human morbidity and mortality compared to normothermic conditions. Many occupations, disease states, as well as stages of life are especially vulnerable to the stress imposed on the cardiovascular system during exposure to hot ambient conditions. This review focuses on the cardiovascular responses to heat stress that are necessary for heat dissipation. To accomplish this regulatory feat requires complex autonomic nervous system control of the heart and various vascular beds. For example, during heat stress cardiac output increases up to twofold, by increases in heart rate and an active maintenance of stroke volume via increases in inotropy in the presence of decreases in cardiac preload. Baroreflexes retain the ability to regulate blood pressure in many, but not all, heat stress conditions. Central hypovolemia is another cardiovascular challenge brought about by heat stress, which if added to a subsequent central volumetric stress, such as hemorrhage, can be problematic and potentially dangerous, as syncope and cardiovascular collapse may ensue. These combined stresses can compromise blood flow and oxygenation to important tissues such as the brain. It is notable that this compromised condition can occur at cardiac outputs that are adequate during normothermic conditions but are inadequate in heat because of the increased systemic vascular conductance associated with cutaneous vasodilation. Understanding the mechanisms within this complex regulatory system will allow for the development of treatment recommendations and countermeasures to reduce risks during the ever-increasing frequency of severe heat events that are predicted to occur.
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Affiliation(s)
- Craig G Crandall
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas and University of Texas Southwestern Medical Center, Dallas, Texas Marian University College of Osteopathic Medicine, Indianapolis, Indiana
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Posnack NG, Brooks D, Chandra A, Jaimes R, Sarvazyan N, Kay M. Physiological response of cardiac tissue to bisphenol A: alterations in ventricular pressure and contractility. Am J Physiol Heart Circ Physiol 2015; 309:H267-75. [PMID: 25980024 DOI: 10.1152/ajpheart.00272.2015] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Accepted: 05/14/2015] [Indexed: 11/22/2022]
Abstract
Biomonitoring studies have indicated that humans are routinely exposed to bisphenol A (BPA), a chemical that is commonly used in the production of polycarbonate plastics and epoxy resins. Epidemiological studies have shown that BPA exposure in humans is associated with cardiovascular disease; however, the direct effects of BPA on cardiac physiology are largely unknown. Previously, we have shown that BPA exposure slows atrioventricular electrical conduction, decreases epicardial conduction velocity, and prolongs action potential duration in excised rat hearts. In the present study, we tested if BPA exposure also adversely affects cardiac contractile performance. We examined the impact of BPA exposure level, sex, and pacing rate on cardiac contractile function in excised rat hearts. Hearts were retrogradely perfused at constant pressure and exposed to 10(-9)-10(-4) M BPA. Left ventricular developed pressure and contractility were measured during sinus rhythm and during pacing (5, 6.5, and 9 Hz). Ca(2+) transients were imaged from whole hearts and from neonatal rat cardiomyocyte layers. During sinus rhythm in female hearts, BPA exposure decreased left ventricular developed pressure and inotropy in a dose-dependent manner. The reduced contractile performance was exacerbated at higher pacing rates. BPA-induced effects on contractile performance were also observed in male hearts, albeit to a lesser extent. Exposure to BPA altered Ca(2+) handling within whole hearts (reduced diastolic and systolic Ca(2+) transient potentiation) and neonatal cardiomyocytes (reduced Ca(2+) transient amplitude and prolonged Ca(2+) transient release time). In conclusion, BPA exposure significantly impaired cardiac performance in a dose-dependent manner, having a major negative impact upon electrical conduction, intracellular Ca(2+) handing, and ventricular contractility.
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Affiliation(s)
- Nikki Gillum Posnack
- Department of Pharmacology and Physiology, School of Medicine and Health Sciences, The George Washington University, Washington, District of Columbia; and
| | - Daina Brooks
- Department of Biomedical Engineering, School of Engineering and Applied Sciences, The George Washington University, Washington, District of Columbia
| | - Akhil Chandra
- Department of Biomedical Engineering, School of Engineering and Applied Sciences, The George Washington University, Washington, District of Columbia
| | - Rafael Jaimes
- Department of Biomedical Engineering, School of Engineering and Applied Sciences, The George Washington University, Washington, District of Columbia
| | - Narine Sarvazyan
- Department of Pharmacology and Physiology, School of Medicine and Health Sciences, The George Washington University, Washington, District of Columbia; and
| | - Matthew Kay
- Department of Biomedical Engineering, School of Engineering and Applied Sciences, The George Washington University, Washington, District of Columbia
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39
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Sanfilippo F, Corredor C, Fletcher N, Landesberg G, Benedetto U, Foex P, Cecconi M. Diastolic dysfunction and mortality in septic patients: a systematic review and meta-analysis. Intensive Care Med 2015; 41:1004-13. [DOI: 10.1007/s00134-015-3748-7] [Citation(s) in RCA: 156] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Accepted: 03/09/2015] [Indexed: 12/23/2022]
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40
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Biesiadecki BJ, Davis JP, Ziolo MT, Janssen PML. Tri-modal regulation of cardiac muscle relaxation; intracellular calcium decline, thin filament deactivation, and cross-bridge cycling kinetics. Biophys Rev 2014; 6:273-289. [PMID: 28510030 PMCID: PMC4255972 DOI: 10.1007/s12551-014-0143-5] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Accepted: 06/27/2014] [Indexed: 01/09/2023] Open
Abstract
Cardiac muscle relaxation is an essential step in the cardiac cycle. Even when the contraction of the heart is normal and forceful, a relaxation phase that is too slow will limit proper filling of the ventricles. Relaxation is too often thought of as a mere passive process that follows contraction. However, many decades of advancements in our understanding of cardiac muscle relaxation have shown it is a highly complex and well-regulated process. In this review, we will discuss three distinct events that can limit the rate of cardiac muscle relaxation: the rate of intracellular calcium decline, the rate of thin-filament de-activation, and the rate of cross-bridge cycling. Each of these processes are directly impacted by a plethora of molecular events. In addition, these three processes interact with each other, further complicating our understanding of relaxation. Each of these processes is continuously modulated by the need to couple bodily oxygen demand to cardiac output by the major cardiac physiological regulators. Length-dependent activation, frequency-dependent activation, and beta-adrenergic regulation all directly and indirectly modulate calcium decline, thin-filament deactivation, and cross-bridge kinetics. We hope to convey our conclusion that cardiac muscle relaxation is a process of intricate checks and balances, and should not be thought of as a single rate-limiting step that is regulated at a single protein level. Cardiac muscle relaxation is a system level property that requires fundamental integration of three governing systems: intracellular calcium decline, thin filament deactivation, and cross-bridge cycling kinetics.
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Affiliation(s)
- Brandon J Biesiadecki
- Department of Physiology and Cell Biology and Dorothy M. Davis Heart Lung Institute, College of Medicine, The Ohio State University, 304 Hamilton Hall, 1645 Neil Avenue, Columbus, OH, 43210-1218, USA
| | - Jonathan P Davis
- Department of Physiology and Cell Biology and Dorothy M. Davis Heart Lung Institute, College of Medicine, The Ohio State University, 304 Hamilton Hall, 1645 Neil Avenue, Columbus, OH, 43210-1218, USA
| | - Mark T Ziolo
- Department of Physiology and Cell Biology and Dorothy M. Davis Heart Lung Institute, College of Medicine, The Ohio State University, 304 Hamilton Hall, 1645 Neil Avenue, Columbus, OH, 43210-1218, USA
| | - Paul M L Janssen
- Department of Physiology and Cell Biology and Dorothy M. Davis Heart Lung Institute, College of Medicine, The Ohio State University, 304 Hamilton Hall, 1645 Neil Avenue, Columbus, OH, 43210-1218, USA.
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41
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Ziolo MT, Houser SR. Abnormal Ca(2+) cycling in failing ventricular myocytes: role of NOS1-mediated nitroso-redox balance. Antioxid Redox Signal 2014; 21:2044-59. [PMID: 24801117 PMCID: PMC4208612 DOI: 10.1089/ars.2014.5873] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
SIGNIFICANCE Heart failure (HF) results from poor heart function and is the leading cause of death in Western society. Abnormalities of Ca(2+) handling at the level of the ventricular myocyte are largely responsible for much of the poor heart function. RECENT ADVANCES Although studies have unraveled numerous mechanisms for the abnormal Ca(2+) handling, investigations over the past decade have indicated that much of the contractile dysfunction and adverse remodeling that occurs in HF involves oxidative stress. CRITICAL ISSUES Regrettably, antioxidant therapy has been an immense disappointment in clinical trials. Thus, redox signaling is being reassessed to elucidate why antioxidants failed to treat HF. FUTURE DIRECTIONS A recently identified aspect of redox signaling (specifically the superoxide anion radical) is its interaction with nitric oxide, known as the nitroso-redox balance. There is a large nitroso-redox imbalance with HF, and we suggest that correcting this imbalance may be able to restore myocyte contraction and improve heart function.
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Affiliation(s)
- Mark T Ziolo
- 1 Department of Physiology and Cell Biology, Davis Heart and Lung Research Institute, The Ohio State University , Columbus, Ohio
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Milani-Nejad N, Brunello L, Gyorke S, Janssen PML. Decrease in sarcoplasmic reticulum calcium content, not myofilament function, contributes to muscle twitch force decline in isolated cardiac trabeculae. J Muscle Res Cell Motil 2014; 35:225-34. [PMID: 25056841 DOI: 10.1007/s10974-014-9386-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2014] [Accepted: 07/07/2014] [Indexed: 10/25/2022]
Abstract
We set out to determine the factors responsible for twitch force decline in isolated intact rat cardiac trabeculae. The contractile force of trabeculae declined over extended periods of isometric twitch contractions. The force-frequency relationship within the frequency range of 4-8 Hz, at 37 °C, became more positive and the frequency optimum shifted to higher rates with this decline in baseline twitch tensions. The post-rest potentiation (37 °C), a phenomenon highly dependent on calcium handling mechanisms, became more pronounced with decrease in twitch tensions. We show that the main abnormality during muscle run-down was not due to a deficit in the myofilaments; maximal tension achieved using a K(+) contracture protocol was either unaffected or only slightly decreased. Conversely, the sarcoplasmic reticulum (SR) calcium content, as assessed by rapid cooling contractures (from 27 to 0 °C), decreased, and had a close association with the declining twitch tensions (R(2) ~ 0.76). SR Ca(2+)-ATPase, relative to Na(+)/Ca(2+) exchanger activity, was not altered as there was no significant change in paired rapid cooling contracture ratios. Furthermore, confocal microscopy detected no abnormalities in the overall structure of the cardiomyocytes and t-tubules in the cardiac trabeculae (~23 °C). Overall, the data indicates that the primary mechanism responsible for force run-down in multi-cellular cardiac preparations is a decline in the SR calcium content and not the maximal tension generation capability of the myofilaments.
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Affiliation(s)
- Nima Milani-Nejad
- Department of Physiology and Cell Biology, College of Medicine, The Ohio State University Wexner Medical Center, 304 Hamilton Hall, 1645 Neil Avenue, Columbus, OH, 43210-1218, USA
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Milani-Nejad N, Janssen PML. Small and large animal models in cardiac contraction research: advantages and disadvantages. Pharmacol Ther 2014; 141:235-49. [PMID: 24140081 PMCID: PMC3947198 DOI: 10.1016/j.pharmthera.2013.10.007] [Citation(s) in RCA: 305] [Impact Index Per Article: 30.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2013] [Accepted: 08/15/2013] [Indexed: 12/22/2022]
Abstract
The mammalian heart is responsible for not only pumping blood throughout the body but also adjusting this pumping activity quickly depending upon sudden changes in the metabolic demands of the body. For the most part, the human heart is capable of performing its duties without complications; however, throughout many decades of use, at some point this system encounters problems. Research into the heart's activities during healthy states and during adverse impacts that occur in disease states is necessary in order to strategize novel treatment options to ultimately prolong and improve patients' lives. Animal models are an important aspect of cardiac research where a variety of cardiac processes and therapeutic targets can be studied. However, there are differences between the heart of a human being and an animal and depending on the specific animal, these differences can become more pronounced and in certain cases limiting. There is no ideal animal model available for cardiac research, the use of each animal model is accompanied with its own set of advantages and disadvantages. In this review, we will discuss these advantages and disadvantages of commonly used laboratory animals including mouse, rat, rabbit, canine, swine, and sheep. Since the goal of cardiac research is to enhance our understanding of human health and disease and help improve clinical outcomes, we will also discuss the role of human cardiac tissue in cardiac research. This review will focus on the cardiac ventricular contractile and relaxation kinetics of humans and animal models in order to illustrate these differences.
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Affiliation(s)
- Nima Milani-Nejad
- Department of Physiology and Cell Biology and D. Davis Heart Lung Institute, College of Medicine, The Ohio State University, OH, USA
| | - Paul M L Janssen
- Department of Physiology and Cell Biology and D. Davis Heart Lung Institute, College of Medicine, The Ohio State University, OH, USA.
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Myocardial Rac1 exhibits partial involvement in thyroxin-induced cardiomyocyte hypertrophy and its inhibition is not sufficient to improve cardiac dysfunction or contractile abnormalities in mouse papillary muscles. J Cardiovasc Pharmacol 2013; 61:536-44. [PMID: 23429587 DOI: 10.1097/fjc.0b013e31828d4b9d] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
: Development of cardiac hypertrophy after thyroxin (T4) treatment is well recognized. Recently, we observed that T4-induced cardiac hypertrophy is associated with increased cardiac Rac1 expression and activity. Whether this Rac1 increase has a role in inducing this cardiac phenotype is, however, still unknown. Here, we showed that T4 treatment (500 µg/kg/d) for 2 weeks resulted in increased myocardial Rac1 activity with subsequent hypertension, cardiac hypertrophy, and left ventricular systolic dysfunction in vivo. Isolated right ventricular papillary muscles of T4-treated mice maintained their peak isometric active developed tension but exhibited significant decreases in their corresponding time to peak and in relaxation times. Positive inotropic responses to increasing pacing rate and β-adrenergic stimulation were also depressed in these muscles. Pravastatin (10 mg/kg/d), a Rac1 inhibitor, significantly decreased myocardial Rac1 activity, hypertension, and cardiomyocyte size in T4-treated mice but could not attenuate gross heart weight or functional cardiac changes in these mice. Our data showed that T4 could activate different signaling pathways with distinct cardiovascular outcomes. We also provide the first mechanistic evidence for the partial involvement of Rac1 activation in T4-induced cardiomyocyte hypertrophy and reveal a putative role for Rac1 in the development of T4-induced hypertension.
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Klabunde RE, LePorte AD, Wilson TE. Effect of temperature on isoproterenol-induced increases in left ventricular developed pressure. J Therm Biol 2013. [DOI: 10.1016/j.jtherbio.2013.05.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Neuronal nitric oxide synthase is indispensable for the cardiac adaptive effects of exercise. Basic Res Cardiol 2013; 108:332. [PMID: 23377961 DOI: 10.1007/s00395-013-0332-6] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2012] [Revised: 01/22/2013] [Accepted: 01/23/2013] [Indexed: 10/27/2022]
Abstract
Exercise results in beneficial adaptations of the heart that can be directly observed at the ventricular myocyte level. However, the molecular mechanism(s) responsible for these adaptations are not well understood. Interestingly, signaling via neuronal nitric oxide synthase (NOS1) within myocytes results in similar effects as exercise. Thus, the objective was to define the role NOS1 plays in the exercise-induced beneficial contractile effects in myocytes. After an 8-week aerobic interval training program, exercise-trained (Ex) mice had higher VO(2max) and cardiac hypertrophy compared to sedentary (Sed) mice. Ventricular myocytes from Ex mice had increased NOS1 expression and nitric oxide production compared to myocytes from Sed mice. Remarkably, acute NOS1 inhibition normalized the enhanced contraction (shortening and Ca(2+) transients) in Ex myocytes to Sed levels. The NOS1 effect on contraction was mediated via greater Ca(2+) cycling that resulted from increased phospholamban phosphorylation. Intriguingly, a similar aerobic interval training program on NOS1 knockout mice failed to produce any beneficial cardiac adaptations (VO(2max), hypertrophy, and contraction). These data demonstrate that the beneficial cardiac adaptations observed after exercise training were mediated via enhanced NOS1 signaling. Therefore, it is likely that beneficial effects of exercise may be mimicked by the interventions that increase NOS1 signaling. This pathway may provide a potential novel therapeutic target in cardiac patients who are unable or unwilling to exercise.
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Vascular Remodeling–Associated Hypertension Leads to Left Ventricular Hypertrophy and Contractile Dysfunction in Profilin-1 Transgenic Mice. J Cardiovasc Pharmacol 2012; 60:544-52. [DOI: 10.1097/fjc.0b013e318271225d] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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Wu Y, Luczak ED, Lee EJ, Hidalgo C, Yang J, Gao Z, Li J, Wehrens X, Granzier H, Anderson ME. CaMKII effects on inotropic but not lusitropic force frequency responses require phospholamban. J Mol Cell Cardiol 2012; 53:429-36. [PMID: 22796260 PMCID: PMC3936404 DOI: 10.1016/j.yjmcc.2012.06.019] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/10/2012] [Revised: 06/04/2012] [Accepted: 06/29/2012] [Indexed: 11/27/2022]
Abstract
Increasing heart rate enhances cardiac contractility (force frequency relationship, FFR) and accelerates cardiac relaxation (frequency-dependent acceleration of relaxation, FDAR). The positive FFR together with FDAR promotes rapid filling and ejection of blood from the left ventricle (LV) at higher heart rates. Recent studies indicate that the multifunctional Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) is involved in regulating FFR and FDAR. We used isolated perfused mouse hearts to study the mechanisms of FFR and FDAR in different genetic models, including transgenic myocardial CaMKII inhibition (AC3-I) and phospholmban knockout (PLN(-/-)). When the rate was increased from 360 beats/min to 630 beats/min in wild type mouse hearts, the LV developed pressure (LVDP) and the maximum rate of increase in pressure (dP/dt max) increased by 37.6 ± 4.7% and 77.0 ± 8.1%, respectively. However, hearts from AC3-I littermates showed no increase of LVDP and a relatively modest (20.4 ± 3.9%) increase in dP/dt max. PLN(-/-) hearts had a negative FFR, and myocardial AC3-I expression did not change the FFR in PLN(-/-) mice. PLN(-/-) mouse hearts did not exhibit FDAR, while PLN(-/-) mice with myocardial AC3-I expression showed further frequency dependent reductions in cardiac relaxation, suggesting that CaMKII targets in addition to PLN were critical to myocardial relaxation. We incubated a constitutively active form of CaMKII with chemically-skinned myocardium and found that several myofilament proteins were phosphorylated by CaMKII. However, CaMKII did not affect myofilament calcium sensitivity. Our study shows that CaMKII plays an important role in modulating FFR and FDAR in murine hearts and suggest that PLN is a critical target for CaMKII effects on FFR, while CaMKII effects on FDAR partially require PLN-alternative targets.
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Affiliation(s)
- Yiming Wu
- Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, IA
| | - Elizabeth D Luczak
- Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, IA
| | - Eun-Jeong Lee
- Department of Physiology, University of Arizona, Tucson, AZ 85724
| | - Carlos Hidalgo
- Department of Physiology, University of Arizona, Tucson, AZ 85724
| | - Jinying Yang
- Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, IA
| | - Zhan Gao
- Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, IA
| | - Jingdong Li
- Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, IA
| | - Xander Wehrens
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX
| | - Henk Granzier
- Department of Physiology, University of Arizona, Tucson, AZ 85724
| | - Mark E Anderson
- Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, IA
- Molecular Physiology and Biophysics, Carver College of Medicine, University of Iowa, Iowa City, IA
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Roof SR, Biesiadecki BJ, Davis JP, Janssen PML, Ziolo MT. Effects of increased systolic Ca(2+) and β-adrenergic stimulation on Ca(2+) transient decline in NOS1 knockout cardiac myocytes. Nitric Oxide 2012; 27:242-7. [PMID: 22960389 DOI: 10.1016/j.niox.2012.08.077] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2012] [Revised: 08/02/2012] [Accepted: 08/24/2012] [Indexed: 12/31/2022]
Abstract
We have previously shown that the main factor responsible for the faster [Ca(2+)](i) decline rate with β-adrenergic (β-AR) stimulation is the phosphorylation of phospholamban (PLB) rather than the increase in systolic Ca(2+) levels. The purpose of this study was to correlate the extent of augmentation of PLB Serine(16) phosphorylation to the rate of [Ca(2+)](i) decline. Thus, ventricular myocytes were isolated from neuronal nitric oxide synthase knockout (NOS1(-/-)) mice, which we observed had lower basal PLB Serine(16) phosphorylation levels, but equal levels during β-AR stimulation. Ca(2+) transients (Fluo-4) were measured in myocytes superfused with 3mM extracellular Ca(2+) ([Ca(2+)](o)) and a non-specific β-AR agonist isoproterenol (ISO, 1μM) with 1mM [Ca(2+)](o). This allowed us to get matched Ca(2+) transient amplitudes in the same myocyte. Similar to our previous work, Ca(2+) transient decline was significantly faster with ISO compared to 3mM [Ca(2+)](o), even with matched Ca(2+) transient amplitudes. Interestingly, when we compared the effects of ISO on Ca(2+) transient decline between NOS1(-/-) and WT myocytes, ISO had a larger effect in NOS1(-/-) myocytes, which resulted in a greater percent decrease in the Ca(2+) transient RT(50). We believe this is due to a greater augmentation of PLB Serine16 phosphorylation in these myocytes. Thus, our results suggest that not only the amount but the extent of augmentation of PLB Serine(16) phosphorylation are the major determinants for the Ca(2+) decline rate. Furthermore, our data suggest that the molecular mechanisms of Ca(2+) transient decline is normal in NOS1(-/-) myocytes and that the slow basal Ca(2+) transient decline is predominantly due to decreased PLB phosphorylation.
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Affiliation(s)
- Steve R Roof
- Department of Physiology & Cell Biology, Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH 43210, USA
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Improvement of left ventricular relaxation as assessed by tissue Doppler imaging in fluid-responsive critically ill septic patients. Intensive Care Med 2012; 38:1461-70. [DOI: 10.1007/s00134-012-2618-9] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2011] [Accepted: 05/31/2012] [Indexed: 10/28/2022]
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