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Gokhan I, Blum TS, Campbell SG. Engineered heart tissue: Design considerations and the state of the art. BIOPHYSICS REVIEWS 2024; 5:021308. [PMID: 38912258 PMCID: PMC11192576 DOI: 10.1063/5.0202724] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2024] [Accepted: 05/29/2024] [Indexed: 06/25/2024]
Abstract
Originally developed more than 20 years ago, engineered heart tissue (EHT) has become an important tool in cardiovascular research for applications such as disease modeling and drug screening. Innovations in biomaterials, stem cell biology, and bioengineering, among other fields, have enabled EHT technologies to recapitulate many aspects of cardiac physiology and pathophysiology. While initial EHT designs were inspired by the isolated-trabecula culture system, current designs encompass a variety of formats, each of which have unique strengths and limitations. In this review, we describe the most common EHT formats, and then systematically evaluate each aspect of their design, emphasizing the rational selection of components for each application.
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Affiliation(s)
| | - Thomas S. Blum
- Department of Biomedical Engineering, Yale University, New Haven, Connecticut 06511, USA
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2
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Elendu C, Amaechi DC, Elendu TC, Fiemotonghan BE, Okoye OK, Agu-Ben CM, Onyekweli SO, Amapu DA, Ikpegbu R, Asekhauno M, Pius E, Bayo-Shodipo AT, Okezie-Okoye CA, Bello N, Oguine C, Edochie P, Dike N, Amos I, Asekhauno J, Wusu-Ejalonibu TM, Ozigi EE, Otobo GO, Olokodana AR, Ayabazu CP, Nwafor RT, Gonji NJ, Akpovona O, Awotoye TI, Ozigis MO, Afolabi O, Alabi OS, Adebayo M. A comprehensive review of heart failure: Unraveling the etiology, decoding pathophysiological mechanisms, navigating diagnostic modalities, exploring pharmacological interventions, advocating lifestyle modifications, and charting the horizon of emerging therapies in the complex landscape of chronic cardiac dysfunction. Medicine (Baltimore) 2024; 103:e36895. [PMID: 38241566 PMCID: PMC10798706 DOI: 10.1097/md.0000000000036895] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/10/2023] [Accepted: 12/18/2023] [Indexed: 01/21/2024] Open
Abstract
Heart failure (HF) poses a significant global health burden, necessitating a profound understanding of its multifaceted dimensions. This comprehensive review aims to unravel the etiology, decode pathophysiological mechanisms, navigate diagnostic modalities, explore pharmacological interventions, advocate lifestyle modifications, and chart the horizon of emerging therapies in the complex landscape of chronic cardiac dysfunction. The exploration of HF begins with an insightful journey into its diverse etiological factors, encompassing genetic predispositions, hypertension, and coronary artery disease. Delving into pathophysiological mechanisms, this review elucidates the intricate processes of cardiac remodeling, neurohormonal activation, and cellular dysfunction that underlie the progression of HF. Diagnostic modalities play a pivotal role in unraveling the mysteries of HF by examining advanced imaging techniques, biomarkers, and comprehensive clinical assessments. The pharmacological interventions section provides an in-depth analysis of traditional medications, such as diuretics and angiotensin-converting enzyme inhibitors, while highlighting the emergence of novel drug classes transforming HF management. Advocating lifestyle modifications emphasizes the crucial role of diet, exercise, smoking cessation, and alcohol moderation in enhancing patient outcomes. Lastly, the review delves into the promising horizon of emerging therapies, offering a glimpse into current research, innovative treatment approaches, and potential breakthroughs. As HF management faces challenges in patient compliance, healthcare access, and education, this comprehensive review aims to equip healthcare professionals and researchers with a holistic understanding of chronic cardiac dysfunction's intricacies. In conclusion, synthesizing key findings emphasizes the need for an integrated and multidimensional approach to effectively address the complex landscape of heart failure.
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Affiliation(s)
| | | | | | | | - Osinachi K. Okoye
- Chukwuemeka Odumegwu Ojukwu University Teaching Hospital, Awka, Nigeria
| | | | | | | | | | | | - Erica Pius
- Babcock University, Ilishan-Remo, Nigeria
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - Otite Akpovona
- King’s College Hospital NHS Foundation Trust, London, England
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3
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Buchanan C, Buchanan C, Riordan M, Byrd J, Schulte M, Kohrt WM, Ambardekar AV, Allen LA, Wolfel G, Lawley J, Levine BD, Cornwell WK. Cardiopulmonary Performance Among Heart Failure Patients Before and After Left Ventricular Assist Device Implantation. JACC. HEART FAILURE 2024; 12:117-129. [PMID: 37632493 DOI: 10.1016/j.jchf.2023.06.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Revised: 06/01/2023] [Accepted: 06/06/2023] [Indexed: 08/28/2023]
Abstract
BACKGROUND Patients with heart failure with reduced ejection fraction (HFrEF) have persistent impairments in functional capacity after continuous-flow left ventricular assist device (CF-LVAD) implantation. OBJECTIVES This study aims to characterize longitudinal changes in exercise hemodynamics and functional capacity among patients with HFrEF before and after CF-LVAD implantation. METHODS Ten patients underwent 3 invasive cardiopulmonary exercise tests on upright cycle ergometry with pulmonary artery catheterization: 1) Visit 1 before CF-LVAD implantation; 2) Visit 2 after device implantation with CF-LVAD pump speed held constant at baseline speed; and 3) Visit 3 with increases in pump speed during exercise (median: 1,050 rpm [IQR: 750-1,150 rpm] and 220 rpm [IQR: 120-220 rpm] for HeartMate 3 and HeartWare VAD, respectively). Hemodynamics and direct Fick cardiac output were monitored using pulmonary artery catheterization. Gas exchange metrics were determined using indirect calorimetry. RESULTS Maximal oxygen uptake (Visits 1, 2, and 3: 10.8 ± 2.5 mL/kg/min, 10.7 ± 2.2 mL/kg/min, and 11.5 ± 1.7 mL/kg/min; P = 0.92) did not improve after device implantation. Mean pulmonary arterial and pulmonary capillary wedge pressures increased significantly during submaximal and peak exercise on preimplantation testing (P < 0.01 for rest vs peak exercise) and remained elevated, with minimal change on Visits 2 and 3 regardless of whether pump speed was fixed or increased. CONCLUSIONS Among patients with HFrEF, cardiovascular hemodynamics and exercise capacity were similar after CF-LVAD implantation, regardless of whether patients exercised at fixed or adjusted pump speeds during exercise. Further research is needed to determine methods by which LVADs may alleviate the HFrEF syndrome after device implantation. (Effect of mechanIcal circulatoRy support ON exercise capacity aMong pAtieNts with heart failure [IRONMAN]; NCT03078972).
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Affiliation(s)
- Cole Buchanan
- Department of Internal Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Collen Buchanan
- Department of Internal Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Maeveen Riordan
- Department of Internal Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Jessica Byrd
- Department of Medicine-Cardiology, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Margaret Schulte
- Colorado Clinical and Translational Sciences Institute, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Wendy M Kohrt
- Colorado Clinical and Translational Sciences Institute, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA; Department of Medicine-Geriatric Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Amrut V Ambardekar
- Department of Medicine-Cardiology, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Larry A Allen
- Department of Medicine-Cardiology, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Gene Wolfel
- Department of Medicine-Cardiology, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Justin Lawley
- Department of Sport Science, Division of Physiology, University of Innsbruck, Innsbruck, Austria
| | - Benjamin D Levine
- Department of Medicine, Division of Cardiology, University of Texas Southwestern Medical Center, and the Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Dallas, Dallas, Texas, USA
| | - William K Cornwell
- Department of Medicine-Cardiology, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA; Colorado Clinical and Translational Sciences Institute, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA.
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4
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Janssens KLPM, Kraamer M, Barbarotta L, Bovendeerd PHM. Post-infarct evolution of ventricular and myocardial function. Biomech Model Mechanobiol 2023; 22:1815-1828. [PMID: 37405536 PMCID: PMC10613149 DOI: 10.1007/s10237-023-01734-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Accepted: 06/04/2023] [Indexed: 07/06/2023]
Abstract
Adverse ventricular remodeling following acute myocardial infarction (MI) may induce ventricular dilation, fibrosis, and loss of global contractile function, possibly resulting in heart failure (HF). Understanding the relation between the time-dependent changes in material properties of the myocardium and the contractile function of the heart may further our understanding of the development of HF post-MI and guide the development of novel therapies. A finite element model of cardiac mechanics was used to model MI in a thick-walled truncated ellipsoidal geometry. Infarct core and border zone comprised 9.6 and 8.1% of the LV wall volume, respectively. Acute MI was modeled by inhibiting active stress generation. Chronic MI was modeled by the additional effect of infarct material stiffening, wall thinning and fiber reorientation. In acute MI, stroke work decreased by 25%. In the infarct core, fiber stress was reduced but fiber strain was increased, depending on the degree of infarct stiffening. Fiber work density was equal to zero. Healthy tissue adjacent to the infarct showed decreased work density depending on the degree of infarct stiffness and the orientation of the myofibers with respect to the infarct region. Thinning of the wall partially restored this loss in work density while the effects of fiber reorientation were minimal. We found that the relative loss in pump function in the infarcted heart exceeds the relative loss in healthy myocardial tissue due to impaired mechanical function in healthy tissue adjacent to the infarct. Infarct stiffening, wall thinning and fiber reorientation did not affect pump function but did affect the distribution of work density in tissue adjacent to the infarct.
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Affiliation(s)
- K L P M Janssens
- Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, 5600MB, The Netherlands.
| | - M Kraamer
- Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, 5600MB, The Netherlands
| | - L Barbarotta
- Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, 5600MB, The Netherlands
| | - P H M Bovendeerd
- Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, 5600MB, The Netherlands
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Edward JA, Parker H, Stöhr EJ, McDonnell BJ, O'Gean K, Schulte M, Lawley JS, Cornwell WK. Exertional Cardiac and Pulmonary Vascular Hemodynamics in Patients With Heart Failure With Reduced Ejection Fraction. J Card Fail 2023; 29:1276-1284. [PMID: 36871613 PMCID: PMC10477310 DOI: 10.1016/j.cardfail.2023.01.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Revised: 01/27/2023] [Accepted: 01/30/2023] [Indexed: 03/07/2023]
Abstract
BACKGROUND Exertional dyspnea is a cardinal manifestation of heart failure with reduced ejection fraction (HFrEF), but quantitative data regarding exertional hemodynamics are lacking. OBJECTIVES We sought to characterize exertional cardiopulmonary hemodynamics in patients with HFrEF. METHODS We studied 35 patients with HFrEF (59 ± 12 years old, 30 males) who completed invasive cardiopulmonary exercise testing. Data were collected at rest, at submaximal exercise and at peak effort on upright cycle ergometry. Cardiovascular and pulmonary vascular hemodynamics were recorded. Fick cardiac output (Qc) was determined. Hemodynamic predictors of peak oxygen uptake (VO2) were identified. RESULTS Left ventricular ejection fraction and cardiac index were 23% ± 8% and 2.9 ± 1.1 L/min/m2, respectively. Peak VO2 was 11.8 ± 3.3 mL/kg/min, and the ventilatory efficiency slope was 53 ± 13. Right atrial pressure increased from rest to peak exercise (4 ± 5 vs 7 ± 6 mmHg,). Mean pulmonary arterial pressure increased from rest to peak exercise (27 ± 13 vs 38 ± 14 mmHg). Pulmonary artery pulsatility index increased from rest to peak exercise, while pulmonary arterial capacitance and pulmonary vascular resistance declined. CONCLUSIONS Patients with HFrEF suffer from marked increases in filling pressures during exercise. These findings provide new insight into cardiopulmonary abnormalities contributing to impairments in exercise capacity in this population. CLINICAL TRIAL REGISTRATION clinicaltrials.gov identifier: NCT03078972.
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Affiliation(s)
- Justin A Edward
- Department of Medicine, Division of Cardiology, University of Colorado Anschutz Medical Campus, Aurora, CO
| | - Hugh Parker
- Department of Medicine, Division of Cardiology, University of Colorado Anschutz Medical Campus, Aurora, CO
| | - Eric J Stöhr
- Leibniz University Hannover, COR-HELIX (Cardiovascular Regulation and Human Exercise Laboratory-Integration and Xploration), Hannover, Germany; Department of Medicine, Division of Cardiology, Columbia University Irving Medical Center, New York NY, USA
| | - Barry J McDonnell
- Cardiovascular Physiology Research Group, Cardiff School of Sport & Health Sciences, Cardiff Metropolitan University, Cardiff, United Kingdom
| | - Katie O'Gean
- Clinical Translational Research Center, University of Colorado Anschutz Medical Campus, Aurora, CO
| | - Margaret Schulte
- Clinical Translational Research Center, University of Colorado Anschutz Medical Campus, Aurora, CO
| | - Justin S Lawley
- University of Innsbruck, Department of Sport Science, Innsbruck, Austria
| | - William K Cornwell
- Department of Medicine, Division of Cardiology, University of Colorado Anschutz Medical Campus, Aurora, CO; Clinical Translational Research Center, University of Colorado Anschutz Medical Campus, Aurora, CO.
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Hanft LM, Robinett JC, Kalogeris TJ, Campbell KS, Biesiadecki BJ, McDonald KS. Thin filament regulation of cardiac muscle power output: Implications for targets to improve human failing hearts. J Gen Physiol 2023; 155:e202213290. [PMID: 37000170 PMCID: PMC10067705 DOI: 10.1085/jgp.202213290] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Revised: 02/14/2023] [Accepted: 03/13/2023] [Indexed: 04/01/2023] Open
Abstract
The heart's pumping capacity is determined by myofilament power generation. Power is work done per unit time and measured as the product of force and velocity. At a sarcomere level, these contractile properties are linked to the number of attached cross-bridges and their cycling rate, and many signaling pathways modulate one or both factors. We previously showed that power is increased in rodent permeabilized cardiac myocytes following PKA-mediated phosphorylation of myofibrillar proteins. The current study found that that PKA increased power by ∼30% in permeabilized cardiac myocyte preparations (n = 8) from human failing hearts. To address myofilament molecular specificity of PKA effects, mechanical properties were measured in rat permeabilized slow-twitch skeletal muscle fibers before and after exchange of endogenous slow skeletal troponin with recombinant human Tn complex that contains cardiac (c)TnT, cTnC and either wildtype (WT) cTnI or pseudo-phosphorylated cTnI at sites Ser23/24Asp, Tyr26Glu, or the combinatorial Ser23/24Asp and Tyr26Glu. We found that cTnI Ser23/24Asp, Tyr26Glu, and combinatorial Ser23/24Asp and Tyr26Glu were sufficient to increase power by ∼20%. Next, we determined whether pseudo-phosphorylated cTnI at Ser23/24 was sufficient to increase power in cardiac myocytes from human failing hearts. Following cTn exchange that included cTnI Ser23/24Asp, power output increased ∼20% in permeabilized cardiac myocyte preparations (n = 6) from the left ventricle of human failing hearts. These results implicate cTnI N-terminal phosphorylation as a molecular regulator of myocyte power and could serve as a regional target for small molecule therapy to unmask myocyte power reserve capacity in human failing hearts.
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Affiliation(s)
- Laurin M. Hanft
- Department of Medical Pharmacology and Physiology, School of Medicine, University of Missouri, Columbia, MO, USA
| | - Joel C. Robinett
- Department of Medical Pharmacology and Physiology, School of Medicine, University of Missouri, Columbia, MO, USA
| | - Theodore J. Kalogeris
- Department of Medical Pharmacology and Physiology, School of Medicine, University of Missouri, Columbia, MO, USA
| | - Kenneth S. Campbell
- Department of Physiology and Division of Cardiovascular Medicine, University of Kentucky, Lexington, KY, USA
| | | | - Kerry S. McDonald
- Department of Medical Pharmacology and Physiology, School of Medicine, University of Missouri, Columbia, MO, USA
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7
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Feng HZ, Huang X, Jin JP. N-terminal truncated cardiac troponin I enhances Frank-Starling response by increasing myofilament sensitivity to resting tension. J Gen Physiol 2023; 155:e202012821. [PMID: 36880803 PMCID: PMC10005897 DOI: 10.1085/jgp.202012821] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Revised: 12/09/2022] [Accepted: 12/29/2022] [Indexed: 03/08/2023] Open
Abstract
Cardiac troponin I (cTnI) of higher vertebrates has evolved with an N-terminal extension, of which deletion via restrictive proteolysis occurs as a compensatory adaptation in chronic heart failure to increase ventricular relaxation and stroke volume. Here, we demonstrate in a transgenic mouse model expressing solely N-terminal truncated cTnI (cTnI-ND) in the heart with deletion of the endogenous cTnI gene. Functional studies using ex vivo working hearts showed an extended Frank-Starling response to preload with reduced left ventricular end diastolic pressure. The enhanced Frank-Starling response effectively increases systolic ventricular pressure development and stroke volume. A novel finding is that cTnI-ND increases left ventricular relaxation velocity and stroke volume without increasing the end diastolic volume. Consistently, the optimal resting sarcomere length (SL) for maximum force development in cTnI-ND cardiac muscle was not different from wild-type (WT) control. Despite the removal of the protein kinase A (PKA) phosphorylation sites in cTnI, β-adrenergic stimulation remains effective on augmenting the enhanced Frank-Starling response of cTnI-ND hearts. Force-pCa relationship studies using skinned preparations found that while cTnI-ND cardiac muscle shows a resting SL-resting tension relationship similar to WT control, cTnI-ND significantly increases myofibril Ca2+ sensitivity to resting tension. The results demonstrate that restrictive N-terminal deletion of cTnI enhances Frank-Starling response by increasing myofilament sensitivity to resting tension rather than directly depending on SL. This novel function of cTnI regulation suggests a myofilament approach to utilizing Frank-Starling mechanism for the treatment of heart failure, especially diastolic failure where ventricular filling is limited.
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Affiliation(s)
- Han-Zhong Feng
- Department of Physiology and Biophysics, University of Illinois at Chicago School of Medicine, Chicago, IL, USA
| | - Xupei Huang
- Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL, USA
| | - Jian-Ping Jin
- Department of Physiology and Biophysics, University of Illinois at Chicago School of Medicine, Chicago, IL, USA
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Tanner BCW, Awinda PO, Agonias KB, Attili S, Blair CA, Thompson MS, Walker LA, Kampourakis T, Campbell KS. Sarcomere length affects Ca2+ sensitivity of contraction in ischemic but not non-ischemic myocardium. J Gen Physiol 2023; 155:213800. [PMID: 36633584 PMCID: PMC9859763 DOI: 10.1085/jgp.202213200] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Revised: 11/18/2022] [Accepted: 12/22/2022] [Indexed: 01/13/2023] Open
Abstract
In healthy hearts, myofilaments become more sensitive to Ca2+ as the myocardium is stretched. This effect is known as length-dependent activation and is an important cellular-level component of the Frank-Starling mechanism. Few studies have measured length-dependent activation in the myocardium from failing human hearts. We investigated whether ischemic and non-ischemic heart failure results in different length-dependent activation responses at physiological temperature (37°C). Myocardial strips from the left ventricular free wall were chemically permeabilized and Ca2+-activated at sarcomere lengths (SLs) of 1.9 and 2.3 µm. Data were acquired from 12 hearts that were explanted from patients receiving cardiac transplants; 6 had ischemic heart failure and 6 had non-ischemic heart failure. Another 6 hearts were obtained from organ donors. Maximal Ca2+-activated force increased at longer SL for all groups. Ca2+ sensitivity increased with SL in samples from donors (P < 0.001) and patients with ischemic heart failure (P = 0.003) but did not change with SL in samples from patients with non-ischemic heart failure. Compared with donors, troponin I phosphorylation decreased in ischemic samples and even more so in non-ischemic samples; cardiac myosin binding protein-C (cMyBP-C) phosphorylation also decreased with heart failure. These findings support the idea that troponin I and cMyBP-C phosphorylation promote length-dependent activation and show that length-dependent activation of contraction is blunted, yet extant, in the myocardium from patients with ischemic heart failure and further reduced in the myocardium from patients with non-ischemic heart failure. Patients who have a non-ischemic disease may exhibit a diminished contractile response to increased ventricular filling.
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Affiliation(s)
- Bertrand C W Tanner
- Department of Integrative Physiology and Neuroscience, Washington State University , Pullman, WA, USA
| | - Peter O Awinda
- Department of Integrative Physiology and Neuroscience, Washington State University , Pullman, WA, USA
| | - Keinan B Agonias
- Department of Integrative Physiology and Neuroscience, Washington State University , Pullman, WA, USA
| | - Seetharamaiah Attili
- Randall Centre for Cell and Molecular Biophysics, King's College London , London, UK
| | - Cheavar A Blair
- Department of Physiology, University of Kentucky , Lexington, KY, USA
| | - Mindy S Thompson
- Department of Physiology, University of Kentucky , Lexington, KY, USA
| | - Lori A Walker
- Division of Cardiology, Department of Medicine, University of Colorado Anschutz Medical Campus , Aurora, CO, USA
| | - Thomas Kampourakis
- Randall Centre for Cell and Molecular Biophysics, King's College London , London, UK
| | - Kenneth S Campbell
- Department of Physiology, University of Kentucky , Lexington, KY, USA.,Division of Cardiovascular Medicine, University of Kentucky , Lexington, KY, USA
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Koirala A, Pourafshar N, Daneshmand A, Wilcox CS, Mannemuddhu SS, Arora N. Etiology and Management of Edema: A Review. ADVANCES IN KIDNEY DISEASE AND HEALTH 2023; 30:110-123. [PMID: 36868727 DOI: 10.1053/j.akdh.2022.12.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Revised: 12/12/2022] [Accepted: 12/14/2022] [Indexed: 04/18/2023]
Abstract
The development of peripheral edema can often pose a significant diagnostic and therapeutic challenge for practitioners due to its association with a wide variety of underlying disorders ranging in severity. Updates to the original Starling's principle have provided new mechanistic insights into edema formation. Additionally, contemporary data highlighting the role of hypochloremia in the development of diuretic resistance provide a possible new therapeutic target. This article reviews the pathophysiology of edema formation and discusses implications for treatment.
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Affiliation(s)
- Abbal Koirala
- Division of Nephrology, University of Washington, Seattle, WA
| | - Negiin Pourafshar
- Division of Nephrology, MedStar Georgetown University Hospital, Washington DC
| | - Arvin Daneshmand
- Division of Nephrology, MedStar Georgetown University Hospital, Washington DC
| | | | | | - Nayan Arora
- Division of Nephrology, University of Washington, Seattle, WA.
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10
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In Vivo Evaluation of a Novel Control Algorithm for Left Ventricular Assist Devices Based Upon Ventricular Stroke Work. ASAIO J 2023; 69:86-95. [PMID: 35420555 DOI: 10.1097/mat.0000000000001722] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
The physical fitness of patients with terminal heart failure and an implanted left ventricular assist device (LVAD) might be improved by load-adaptive control of the LVAD. In this study, three control strategies for LVAD were compared in eight pigs: (1) a constant stroke work (CSW) control strategy that ensures a constant ventricular load using ventricular stroke work as the control variable; (2) a work ratio (WR) controller that maintains a constant ratio of ventricular work to hydraulic pump work; and (3) a controller that maintains the pump pace at a constant speed (CS). Biventricular heart insufficiency was induced by increased isoflurane application, and preload, afterload, and contractility alterations were performed. LVAD speed changes were significantly more pronounced in all load interventions with the CSW control strategy (preload: P < 0.001 vs. CS and P = 0.004 vs. WR; afterload: P < 0.001 vs. CS and P < 0.001 vs. WR; contractility: P < 0.001 vs. CS and P < 0.001 vs. WR). However, a significant difference in systemic flow only became evident in the experiments upon afterload increase ( P < 0.001 vs. CS and P = 0.004 vs. WR). An implementation of an evolved version of the CSW control strategy that dispenses with invasively measured parameters might be feasible for clinical use.
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11
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Hu Z, Gao S, Yang J, Xu B, Tang W, Bradley JL, Peberdy MA, Ornato JP. IVABRADINE-INDUCED HEART RATE REDUCTION INCREASES THE SEVERITY OF POSTRESUSCITATION MYOCARDIAL DYSFUNCTION IN A RAT MODEL OF CARDIOPULMONARY RESUSCITATION. Shock 2022; 58:573-581. [PMID: 36548647 PMCID: PMC9803391 DOI: 10.1097/shk.0000000000002020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Revised: 09/14/2022] [Accepted: 10/19/2022] [Indexed: 12/24/2022]
Abstract
ABSTRACT Aims: A rapid heart rate (HR) that occurs after cardiopulmonary resuscitation (CPR) is a short-term compensatory mechanism preserving cardiac output. However, if of long duration, it is unfavorable for myocardial function postresuscitation because of disrupted balance between myocardial oxygen supply and demand. This raises the assumption that such a sustained fast HR should be regulated. The present study aimed to investigate the follow-on effect of ivabradine (a specific inhibitor of the I f current of the sinoatrial node)-induced HR reduction (HRR) on postresuscitation myocardial function in a rat model of CPR. Methods and results: Six minutes of ventricular fibrillation and 8 min of CPR were performed on Sprague-Dawley rats. All 32 resuscitated animals were then randomized into saline and ivabradine groups, each group having nonsurvival and survival subgroups (n = 8 each). Saline or ivabradine (0.5 mL/kg) was administered at 1 h postresuscitation. Heart rate, myocardial function as expressed by cardiac output, ejection fraction, and myocardial performance index were assessed at baseline and hourly from 1 to 5 h postresuscitation. Heart rate variability was analyzed at baseline and at 1, 3, and 5 h postresuscitation. Serum epinephrine and cardiac troponin I at baseline and at 1, 3, and 5 h postresuscitation in nonsurvival subgroup were measured. Survival duration in the survival subgroup was observed. The baseline HR was approximately 390 beats/min (bpm). After resuscitation, an average increase of Δ ≈ +15 bpm (relative ratio ≈ +3.8%) with a resultant HR of 405 bpm lasting more than 5 h occurred. Ivabradine group achieved a steady HRR of Δ ≈ -30 bpm (relative ratio ≈ -7.4%) as compared with saline group ( P < 0.01). Postresuscitation myocardial function was significantly worse in the ivabradine group (all P < 0.01). Heart rate variability was significantly impaired in the ivabradine group (all P < 0.05). Serum cardiac troponin I and epinephrine concentration were significantly higher in the ivabradine group (all P < ?0.01). Survival duration was significantly shortened in the ivabradine group as compared with the saline group (388 vs. 526 min, P < ?0.01). Conclusions: Ivabradine-induced HRR increases the severity of postresuscitation myocardial dysfunction and shortens survival duration in a rat model of CPR.
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Affiliation(s)
- Zhangle Hu
- Department of Pharmacology, Basic Medical College, Anhui Medical University, Hefei, Anhui, China
- Department of Cardiology, The Second Hospital of Anhui Medical University, Hefei, Anhui, China
- Weil Institute of Emergency and Critical Care Research, Virginia Commonwealth University, Richmond, VA
| | - Shan Gao
- Department of Pharmacology, Basic Medical College, Anhui Medical University, Hefei, Anhui, China
| | - Jin Yang
- Department of Respiratory Medicine, The Second Hospital of Anhui Medical University, Hefei, China
| | - Banglong Xu
- Department of Cardiology, The Second Hospital of Anhui Medical University, Hefei, Anhui, China
| | - Wanchun Tang
- Weil Institute of Emergency and Critical Care Research, Virginia Commonwealth University, Richmond, VA
| | - Jennifer L. Bradley
- Weil Institute of Emergency and Critical Care Research, Virginia Commonwealth University, Richmond, VA
| | - Mary Ann Peberdy
- Weil Institute of Emergency and Critical Care Research, Virginia Commonwealth University, Richmond, VA
| | - Joseph P. Ornato
- Weil Institute of Emergency and Critical Care Research, Virginia Commonwealth University, Richmond, VA
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12
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Stachowski-Doll MJ, Papadaki M, Martin TG, Ma W, Gong HM, Shao S, Shen S, Muntu NA, Kumar M, Perez E, Martin JL, Moravec CS, Sadayappan S, Campbell SG, Irving T, Kirk JA. GSK-3β Localizes to the Cardiac Z-Disc to Maintain Length Dependent Activation. Circ Res 2022; 130:871-886. [PMID: 35168370 PMCID: PMC8930626 DOI: 10.1161/circresaha.121.319491] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Altered kinase localization is gaining appreciation as a mechanism of cardiovascular disease. Previous work suggests GSK-3β (glycogen synthase kinase 3β) localizes to and regulates contractile function of the myofilament. We aimed to discover GSK-3β's in vivo role in regulating myofilament function, the mechanisms involved, and the translational relevance. METHODS Inducible cardiomyocyte-specific GSK-3β knockout mice and left ventricular myocardium from nonfailing and failing human hearts were studied. RESULTS Skinned cardiomyocytes from knockout mice failed to exhibit calcium sensitization with stretch indicating a loss of length-dependent activation (LDA), the mechanism underlying the Frank-Starling Law. Titin acts as a length sensor for LDA, and knockout mice had decreased titin stiffness compared with control mice, explaining the lack of LDA. Knockout mice exhibited no changes in titin isoforms, titin phosphorylation, or other thin filament phosphorylation sites known to affect passive tension or LDA. Mass spectrometry identified several z-disc proteins as myofilament phospho-substrates of GSK-3β. Agreeing with the localization of its targets, GSK-3β that is phosphorylated at Y216 binds to the z-disc. We showed pY216 was necessary and sufficient for z-disc binding using adenoviruses for wild-type, Y216F, and Y216E GSK-3β in neonatal rat ventricular cardiomyocytes. One of GSK-3β's z-disc targets, abLIM-1 (actin-binding LIM protein 1), binds to the z-disc domains of titin that are important for maintaining passive tension. Genetic knockdown of abLIM-1 via siRNA in human engineered heart tissues resulted in enhancement of LDA, indicating abLIM-1 may act as a negative regulator that is modulated by GSK-3β. Last, GSK-3β myofilament localization was reduced in left ventricular myocardium from failing human hearts, which correlated with depressed LDA. CONCLUSIONS We identified a novel mechanism by which GSK-3β localizes to the myofilament to modulate LDA. Importantly, z-disc GSK-3β levels were reduced in patients with heart failure, indicating z-disc localized GSK-3β is a possible therapeutic target to restore the Frank-Starling mechanism in patients with heart failure.
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Affiliation(s)
- Marisa J Stachowski-Doll
- Department of Cell and Molecular Physiology, Loyola University Stritch School of Medicine, Maywood, IL (M.J.S.-D., M.P., T.G.M., N.A.M., E.P., J.A.K.)
| | - Maria Papadaki
- Department of Cell and Molecular Physiology, Loyola University Stritch School of Medicine, Maywood, IL (M.J.S.-D., M.P., T.G.M., N.A.M., E.P., J.A.K.)
| | - Thomas G Martin
- Department of Cell and Molecular Physiology, Loyola University Stritch School of Medicine, Maywood, IL (M.J.S.-D., M.P., T.G.M., N.A.M., E.P., J.A.K.)
| | - Weikang Ma
- Center for Synchrotron Radiation Research and Instrumentation and Department of Biological Sciences, Illinois Institute of Technology, Chicago (W.M., H.M.G., T.I.)
| | - Henry M Gong
- Center for Synchrotron Radiation Research and Instrumentation and Department of Biological Sciences, Illinois Institute of Technology, Chicago (W.M., H.M.G., T.I.)
| | - Stephanie Shao
- Department of Bioengineering, Yale University, New Haven, CT (S. Shao, S. Shen, S.G.C.)
| | - Shi Shen
- Department of Bioengineering, Yale University, New Haven, CT (S. Shao, S. Shen, S.G.C.)
| | - Nitha Aima Muntu
- Department of Cell and Molecular Physiology, Loyola University Stritch School of Medicine, Maywood, IL (M.J.S.-D., M.P., T.G.M., N.A.M., E.P., J.A.K.)
| | - Mohit Kumar
- Division of Cardiovascular Health and Disease, Department of Internal Medicine, Heart, Lung, and Vascular Institute, University of Cincinnati, OH (M.K., S. Sadayappan)
| | - Edith Perez
- Department of Cell and Molecular Physiology, Loyola University Stritch School of Medicine, Maywood, IL (M.J.S.-D., M.P., T.G.M., N.A.M., E.P., J.A.K.)
| | - Jody L Martin
- Department of Pharmacology, Cardiovascular Research Institute, UC Davis School of Medicine, CA (J.L.M.)
| | - Christine S Moravec
- Department of Cardiovascular and Metabolic Sciences, Cleveland Clinic, OH (C.S.M.)
| | - Sakthivel Sadayappan
- Division of Cardiovascular Health and Disease, Department of Internal Medicine, Heart, Lung, and Vascular Institute, University of Cincinnati, OH (M.K., S. Sadayappan)
| | - Stuart G Campbell
- Department of Bioengineering, Yale University, New Haven, CT (S. Shao, S. Shen, S.G.C.).,Department of Cellular and Molecular Physiology, Yale School of Medicine, New Haven, CT (S.G.C.)
| | - Thomas Irving
- Center for Synchrotron Radiation Research and Instrumentation and Department of Biological Sciences, Illinois Institute of Technology, Chicago (W.M., H.M.G., T.I.)
| | - Jonathan A Kirk
- Department of Cell and Molecular Physiology, Loyola University Stritch School of Medicine, Maywood, IL (M.J.S.-D., M.P., T.G.M., N.A.M., E.P., J.A.K.)
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13
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Ma W, Irving TC. Small Angle X-ray Diffraction as a Tool for Structural Characterization of Muscle Disease. Int J Mol Sci 2022; 23:3052. [PMID: 35328477 PMCID: PMC8949570 DOI: 10.3390/ijms23063052] [Citation(s) in RCA: 32] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Revised: 03/01/2022] [Accepted: 03/02/2022] [Indexed: 02/01/2023] Open
Abstract
Small angle X-ray fiber diffraction is the method of choice for obtaining molecular level structural information from striated muscle fibers under hydrated physiological conditions. For many decades this technique had been used primarily for investigating basic biophysical questions regarding muscle contraction and regulation and its use confined to a relatively small group of expert practitioners. Over the last 20 years, however, X-ray diffraction has emerged as an important tool for investigating the structural consequences of cardiac and skeletal myopathies. In this review we show how simple and straightforward measurements, accessible to non-experts, can be used to extract biophysical parameters that can help explain and characterize the physiology and pathology of a given experimental system. We provide a comprehensive guide to the range of the kinds of measurements that can be made and illustrate how they have been used to provide insights into the structural basis of pathology in a comprehensive review of the literature. We also show how these kinds of measurements can inform current controversies and indicate some future directions.
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Affiliation(s)
- Weikang Ma
- The Biophysics Collaborative Access Team (BioCAT), Center for Synchrotron Radiation Research and Instrumentation (CSSRI), Illinois Institute of Technology, Chicago, IL 60616, USA;
- Department of Biology, Illinois Institute of Technology, Chicago, IL 60616, USA
| | - Thomas C. Irving
- The Biophysics Collaborative Access Team (BioCAT), Center for Synchrotron Radiation Research and Instrumentation (CSSRI), Illinois Institute of Technology, Chicago, IL 60616, USA;
- Department of Biology, Illinois Institute of Technology, Chicago, IL 60616, USA
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14
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Pitoulis FG, Nunez-Toldra R, Xiao K, Kit-Anan W, Mitzka S, Jabbour RJ, Harding SE, Perbellini F, Thum T, de Tombe PP, Terracciano CM. Remodelling of adult cardiac tissue subjected to physiological and pathological mechanical load in vitro. Cardiovasc Res 2022; 118:814-827. [PMID: 33723566 PMCID: PMC8859636 DOI: 10.1093/cvr/cvab084] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Accepted: 03/11/2021] [Indexed: 01/14/2023] Open
Abstract
AIMS Cardiac remodelling is the process by which the heart adapts to its environment. Mechanical load is a major driver of remodelling. Cardiac tissue culture has been frequently employed for in vitro studies of load-induced remodelling; however, current in vitro protocols (e.g. cyclic stretch, isometric load, and auxotonic load) are oversimplified and do not accurately capture the dynamic sequence of mechanical conformational changes experienced by the heart in vivo. This limits translational scope and relevance of findings. METHODS AND RESULTS We developed a novel methodology to study chronic load in vitro. We first developed a bioreactor that can recreate the electromechanical events of in vivo pressure-volume loops as in vitro force-length loops. We then used the bioreactor to culture rat living myocardial slices (LMS) for 3 days. The bioreactor operated based on a 3-Element Windkessel circulatory model enabling tissue mechanical loading based on physiologically relevant parameters of afterload and preload. LMS were continuously stretched/relaxed during culture simulating conditions of physiological load (normal preload and afterload), pressure-overload (normal preload and high afterload), or volume-overload (high preload & normal afterload). At the end of culture, functional, structural, and molecular assays were performed to determine load-induced remodelling. Both pressure- and volume-overloaded LMS showed significantly decreased contractility that was more pronounced in the latter compared with physiological load (P < 0.0001). Overloaded groups also showed cardiomyocyte hypertrophy; RNAseq identified shared and unique genes expressed in each overload group. The PI3K-Akt pathway was dysregulated in volume-overload while inflammatory pathways were mostly associated with remodelling in pressure-overloaded LMS. CONCLUSION We have developed a proof-of-concept platform and methodology to recreate remodelling under pathophysiological load in vitro. We show that LMS cultured in our bioreactor remodel as a function of the type of mechanical load applied to them.
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Affiliation(s)
- Fotios G Pitoulis
- National Heart and Lung Institute, Imperial College London, 72 Du Cane Road, Hammersmith Hospital, ICTEM Building, W12 0NN London, UK
| | - Raquel Nunez-Toldra
- National Heart and Lung Institute, Imperial College London, 72 Du Cane Road, Hammersmith Hospital, ICTEM Building, W12 0NN London, UK
| | - Ke Xiao
- Institute for Molecular and Translational Therapeutic Strategies, Hannover Medical School, OE 8886, Carl-Neuberg-Str. 1, J3 Building, Level 1, Room 3030, 30625 Hannover, Germany
| | - Worrapong Kit-Anan
- National Heart and Lung Institute, Imperial College London, 72 Du Cane Road, Hammersmith Hospital, ICTEM Building, W12 0NN London, UK
| | - Saskia Mitzka
- Institute for Molecular and Translational Therapeutic Strategies, Hannover Medical School, OE 8886, Carl-Neuberg-Str. 1, J3 Building, Level 1, Room 3030, 30625 Hannover, Germany
| | - Richard J Jabbour
- National Heart and Lung Institute, Imperial College London, 72 Du Cane Road, Hammersmith Hospital, ICTEM Building, W12 0NN London, UK
| | - Sian E Harding
- National Heart and Lung Institute, Imperial College London, 72 Du Cane Road, Hammersmith Hospital, ICTEM Building, W12 0NN London, UK
| | - Filippo Perbellini
- Institute for Molecular and Translational Therapeutic Strategies, Hannover Medical School, OE 8886, Carl-Neuberg-Str. 1, J3 Building, Level 1, Room 3030, 30625 Hannover, Germany
| | - Thomas Thum
- National Heart and Lung Institute, Imperial College London, 72 Du Cane Road, Hammersmith Hospital, ICTEM Building, W12 0NN London, UK
- Institute for Molecular and Translational Therapeutic Strategies, Hannover Medical School, OE 8886, Carl-Neuberg-Str. 1, J3 Building, Level 1, Room 3030, 30625 Hannover, Germany
| | - Pieter P de Tombe
- Department of Physiology and Biophysics, University of Illinois at Chicago, 835 S. Wolcott Rm E202 (MC901), Chicago, IL 60612-7342, USA
| | - Cesare M Terracciano
- National Heart and Lung Institute, Imperial College London, 72 Du Cane Road, Hammersmith Hospital, ICTEM Building, W12 0NN London, UK
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15
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Methawasin M, Farman GP, Granzier-Nakajima S, Strom J, Kiss B, Smith JE, Granzier H. Shortening the thick filament by partial deletion of titin's C-zone alters cardiac function by reducing the operating sarcomere length range. J Mol Cell Cardiol 2022; 165:103-114. [PMID: 35031281 PMCID: PMC8940690 DOI: 10.1016/j.yjmcc.2022.01.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Revised: 01/06/2022] [Accepted: 01/07/2022] [Indexed: 10/19/2022]
Abstract
Titin's C-zone is an inextensible segment in titin, comprised of 11 super-repeats and located in the cMyBP-C-containing region of the thick filament. Previously we showed that deletion of titin's super-repeats C1 and C2 (TtnΔC1-2 model) results in shorter thick filaments and contractile dysfunction of the left ventricular (LV) chamber but that unexpectedly LV diastolic stiffness is normal. Here we studied the contraction-relaxation kinetics from the time-varying elastance of the LV and intact cardiomyocyte, cellular work loops of intact cardiomyocytes, Ca2+ transients, cross-bridge kinetics, and myofilament Ca2+ sensitivity. Intact cardiomyocytes of TtnΔC1-2 mice exhibit systolic dysfunction and impaired relaxation. The time-varying elastance at both LV and single-cell levels showed that activation kinetics are normal in TtnΔC1-2 mice, but that relaxation is slower. The slowed relaxation is, in part, attributable to an increased myofilament Ca2+ sensitivity and slower early Ca2+ reuptake. Cross-bridge dynamics showed that cross-bridge kinetics are normal but that the number of force-generating cross-bridges is reduced. In vivo sarcomere length (SL) measurements revealed that in TtnΔC1-2 mice the operating SL range of the LV is shifted towards shorter lengths. This normalizes the apparent cell and LV diastolic stiffness but further reduces systolic force as systole occurs further down on the ascending limb of the force-SL relation. We propose that the reduced working SLs reflect titin's role in regulating diastolic stiffness by altering the number of sarcomeres in series. Overall, our study reveals that thick filament length regulation by titin's C-zone is critical for normal cardiac function.
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Affiliation(s)
- Mei Methawasin
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, AZ 85721, United States of America.
| | - Gerrie P Farman
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, AZ 85721, United States of America
| | - Shawtaroh Granzier-Nakajima
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, AZ 85721, United States of America
| | - Joshua Strom
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, AZ 85721, United States of America
| | - Balazs Kiss
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, AZ 85721, United States of America
| | - John E Smith
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, AZ 85721, United States of America
| | - Henk Granzier
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, AZ 85721, United States of America.
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16
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Bhullar S, Shah A, Dhalla N. Mechanisms for the development of heart failure and improvement of cardiac function by angiotensin-converting enzyme inhibitors. SCRIPTA MEDICA 2022. [DOI: 10.5937/scriptamed53-36256] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022] Open
Abstract
Angiotensin-converting enzyme (ACE) inhibitors, which prevent the conversion of angiotensin I to angiotensin II, are well-known for the treatments of cardiovascular diseases, such as heart failure, hypertension and acute coronary syndrome. Several of these inhibitors including captopril, enalapril, ramipril, zofenopril and imidapril attenuate vasoconstriction, cardiac hypertrophy and adverse cardiac remodeling, improve clinical outcomes in patients with cardiac dysfunction and decrease mortality. Extensive experimental and clinical research over the past 35 years has revealed that the beneficial effects of ACE inhibitors in heart failure are associated with full or partial prevention of adverse cardiac remodeling. Since cardiac function is mainly determined by coordinated activities of different subcellular organelles, including sarcolemma, sarcoplasmic reticulum, mitochondria and myofibrils, for regulating the intracellular concentration of Ca2+ and myocardial metabolism, there is ample evidence to suggest that adverse cardiac remodelling and cardiac dysfunction in the failing heart are the consequence of subcellular defects. In fact, the improvement of cardiac function by different ACE inhibitors has been demonstrated to be related to the attenuation of abnormalities in subcellular organelles for Ca2+-handling, metabolic alterations, signal transduction defects and gene expression changes in failing cardiomyocytes. Various ACE inhibitors have also been shown to delay the progression of heart failure by reducing the formation of angiotensin II, the development of oxidative stress, the level of inflammatory cytokines and the occurrence of subcellular defects. These observations support the view that ACE inhibitors improve cardiac function in the failing heart by multiple mechanisms including the reduction of oxidative stress, myocardial inflammation and Ca2+-handling abnormalities in cardiomyocytes.
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17
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Ma W, Henze M, Anderson RL, Gong H, Wong FL, Del Rio CL, Irving T. The Super-Relaxed State and Length Dependent Activation in Porcine Myocardium. Circ Res 2021; 129:617-630. [PMID: 34365814 DOI: 10.1161/circresaha.120.318647] [Citation(s) in RCA: 43] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
[Figure: see text].
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Affiliation(s)
- Weikang Ma
- BioCAT, Department of Biological Sciences, Illinois Institute of Technology, Chicago (W.M., H.G., T.I.)
| | - Marcus Henze
- MyoKardia Inc, Brisbane, CA (M.H., R.L.A., F.L.W., C.L.d.R.)
| | | | - Henry Gong
- BioCAT, Department of Biological Sciences, Illinois Institute of Technology, Chicago (W.M., H.G., T.I.)
| | - Fiona L Wong
- MyoKardia Inc, Brisbane, CA (M.H., R.L.A., F.L.W., C.L.d.R.)
| | | | - Thomas Irving
- BioCAT, Department of Biological Sciences, Illinois Institute of Technology, Chicago (W.M., H.G., T.I.)
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18
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Hanft LM, Fitzsimons DP, Hacker TA, Moss RL, McDonald KS. Cardiac MyBP-C phosphorylation regulates the Frank-Starling relationship in murine hearts. J Gen Physiol 2021; 153:e202012770. [PMID: 33646280 PMCID: PMC7927661 DOI: 10.1085/jgp.202012770] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Revised: 01/04/2021] [Accepted: 01/26/2021] [Indexed: 01/08/2023] Open
Abstract
The Frank-Starling relationship establishes that elevated end-diastolic volume progressively increases ventricular pressure and stroke volume in healthy hearts. The relationship is modulated by a number of physiological inputs and is often depressed in human heart failure. Emerging evidence suggests that cardiac myosin-binding protein-C (cMyBP-C) contributes to the Frank-Starling relationship. We measured contractile properties at multiple levels of structural organization to determine the role of cMyBP-C and its phosphorylation in regulating (1) the sarcomere length dependence of power in cardiac myofilaments and (2) the Frank-Starling relationship in vivo. We compared transgenic mice expressing wild-type cMyBP-C on the null background, which have ∼50% phosphorylated cMyBP-C (Controls), to transgenic mice lacking cMyBP-C (KO) and to mice expressing cMyBP-C that have serine-273, -282, and -302 mutated to aspartate (cMyBP-C t3SD) or alanine (cMyBP-C t3SA) on the null background to mimic either constitutive PKA phosphorylation or nonphosphorylated cMyBP-C, respectively. We observed a continuum of length dependence of power output in myocyte preparations. Sarcomere length dependence of power progressively increased with a rank ordering of cMyBP-C KO = cMyBP-C t3SA < Control < cMyBP-C t3SD. Length dependence of myofilament power translated, at least in part, to hearts, whereby Frank-Starling relationships were steepest in cMyBP-C t3SD mice. The results support the hypothesis that cMyBP-C and its phosphorylation state tune sarcomere length dependence of myofibrillar power, and these regulatory processes translate across spatial levels of myocardial organization to control beat-to-beat ventricular performance.
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Affiliation(s)
- Laurin M. Hanft
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, MO
| | - Daniel P. Fitzsimons
- Department of Cell and Regenerative Biology, University of Wisconsin-Madison, Madison, WI
| | - Timothy A. Hacker
- Department of Medicine, University of Wisconsin-Madison, Madison, WI
| | - Richard L. Moss
- Department of Cell and Regenerative Biology, University of Wisconsin-Madison, Madison, WI
| | - Kerry S. McDonald
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, MO
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19
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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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Sekma A, Bel Haj Ali K, Jeddi C, Ben Brahim N, Bzeouich N, Gannoun I, Trabelssi I, Laouiti K, Grissa MH, Beltaief K, Zohra D, Asma Z, Lotfi B, Rym Y, Ben Soltane H, Zied M, Mariem K, Msolli MA, Riadh B, Bouida W, Boubaker H, Nouira S. Value of nitroglycerin test in the diagnosis of heart failure in emergency department patients with undifferentiated dyspnea. Clin Cardiol 2021; 44:932-937. [PMID: 34076282 PMCID: PMC8259157 DOI: 10.1002/clc.23615] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 04/07/2021] [Accepted: 04/19/2021] [Indexed: 01/06/2023] Open
Abstract
Background Rapid diagnosis of heart failure (HF) in acutely dyspneic patients can be challenging for emergency department (ED) physicians. Hypothesis Cardiac output (CO) change with sublingual nitroglycerin (NTG) could be helpful in the diagnosis of HF in patients with acute undifferentiated dyspnea. Materials and Methods A prospective study of patients >18 years admitted to the ED for acute dyspnea. Using thoracic bioimpedance, we measured CO change at baseline and after sublingual administration of 0.6 mg of NTG. HF was defined on the basis of clinical examination, pro‐brain natriuretic peptide levels, and echocardiographic findings. Diagnostic performance of delta CO was calculated by sensitivity, specificity, likelihood ratio and receiver operating characteristic (ROC) curve. Results This study included 184 patients with mean age of 64 years. Baseline CO was comparable between the HF group and the non‐HF group. At its best cutoff (29%), delta CO showed good accuracy in the diagnosis of HF with a sensitivity, specificity, positive and negative likelihood ratios of 80%, 44%, 57%, and 66% respectively. Area under ROC curve was 0.701 [95% CI 0.636–0.760]. The decrease of CO with sublingual NTG was significantly higher in patients with HFpEF compared with those with HFrEF. Multivariate analysis, showed that delta CO was an independent factor associated with HF diagnosis [OR 0.19 (95% CI 0.11–0.29); p < .001]. Conclusions Our study showed that CO change with sublingual nitroglycerin is a simple tool that may be helpful for the diagnosis of HF in ED patients with undifferentiated dyspnea.
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Affiliation(s)
- Adel Sekma
- Emergency Department, Fattouma Bourguiba University Hospital, Monastir, Tunisia.,Research Laboratory LR12SP18, University of Monastir, Monastir, Tunisia
| | - Khaoula Bel Haj Ali
- Emergency Department, Fattouma Bourguiba University Hospital, Monastir, Tunisia.,Research Laboratory LR12SP18, University of Monastir, Monastir, Tunisia
| | - Camilia Jeddi
- Emergency Department, Fattouma Bourguiba University Hospital, Monastir, Tunisia.,Research Laboratory LR12SP18, University of Monastir, Monastir, Tunisia
| | - Nadia Ben Brahim
- Emergency Department, Fattouma Bourguiba University Hospital, Monastir, Tunisia.,Research Laboratory LR12SP18, University of Monastir, Monastir, Tunisia
| | - Nasri Bzeouich
- Emergency Department, Fattouma Bourguiba University Hospital, Monastir, Tunisia.,Research Laboratory LR12SP18, University of Monastir, Monastir, Tunisia
| | - Imen Gannoun
- Research Laboratory LR12SP18, University of Monastir, Monastir, Tunisia
| | - Imen Trabelssi
- Research Laboratory LR12SP18, University of Monastir, Monastir, Tunisia
| | - Kamel Laouiti
- Emergency Department, Fattouma Bourguiba University Hospital, Monastir, Tunisia.,Research Laboratory LR12SP18, University of Monastir, Monastir, Tunisia
| | - Mohamed Habib Grissa
- Emergency Department, Fattouma Bourguiba University Hospital, Monastir, Tunisia.,Research Laboratory LR12SP18, University of Monastir, Monastir, Tunisia
| | - Kaouthar Beltaief
- Emergency Department, Fattouma Bourguiba University Hospital, Monastir, Tunisia.,Research Laboratory LR12SP18, University of Monastir, Monastir, Tunisia
| | - Dridi Zohra
- Cardiology Department, Fattouma Bourguiba University Hospital, Monastir, Tunisia
| | - Zorgati Asma
- Research Laboratory LR12SP18, University of Monastir, Monastir, Tunisia.,Emergency Department, Sahloul University Hospital, Sousse, Tunisia
| | - Boukadida Lotfi
- Research Laboratory LR12SP18, University of Monastir, Monastir, Tunisia.,Emergency Department, Sahloul University Hospital, Sousse, Tunisia
| | - Youssef Rym
- Research Laboratory LR12SP18, University of Monastir, Monastir, Tunisia.,Emergency Department, Sahloul University Hospital, Sousse, Tunisia
| | - Houda Ben Soltane
- Emergency Department, Farhat Hached University Hospital, Sousse, Tunisia
| | - Mezgar Zied
- Emergency Department, Farhat Hached University Hospital, Sousse, Tunisia
| | - Khrouf Mariem
- Emergency Department, Farhat Hached University Hospital, Sousse, Tunisia
| | - Mohamed Amine Msolli
- Emergency Department, Fattouma Bourguiba University Hospital, Monastir, Tunisia.,Research Laboratory LR12SP18, University of Monastir, Monastir, Tunisia
| | - Boukef Riadh
- Research Laboratory LR12SP18, University of Monastir, Monastir, Tunisia.,Emergency Department, Sahloul University Hospital, Sousse, Tunisia
| | - Wahid Bouida
- Emergency Department, Fattouma Bourguiba University Hospital, Monastir, Tunisia.,Research Laboratory LR12SP18, University of Monastir, Monastir, Tunisia
| | - Hamdi Boubaker
- Emergency Department, Fattouma Bourguiba University Hospital, Monastir, Tunisia.,Research Laboratory LR12SP18, University of Monastir, Monastir, Tunisia
| | - Semir Nouira
- Emergency Department, Fattouma Bourguiba University Hospital, Monastir, Tunisia.,Research Laboratory LR12SP18, University of Monastir, Monastir, Tunisia
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21
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Bel Haj Ali K, Sekma A, Msolli MA, Bezouich N, Gannoun I, Grissa MH, Boubaker H, Beltaief K, Dridi Z, Nouira S. Value of DYnamicVariation of impedance cardiac output in the diagnosis of heart failure in emergency department patients with undifferentiated dyspnea. Am J Emerg Med 2021; 49:29-34. [PMID: 34051399 DOI: 10.1016/j.ajem.2021.05.042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2020] [Revised: 05/08/2021] [Accepted: 05/14/2021] [Indexed: 10/21/2022] Open
Abstract
AIM OF STUDY Cardiac output (CO) responses to acute changes in body position and Valsalva maneuver (VM) were proposed to assess cardiac contractile reserve. We investigated the value of sitting position (SP), leg raising (LR), and VM for identifying heart failure (HF) in patients with undifferentiated dyspnea. MATERIALS AND METHODS It is a prospective study including patients over 18 years old admitted to the emergency department (ED) for dyspnea. Bioimpedance CO was measured at baseline, under SP, LR, and VM. HF diagnosis was based on clinical assessment, serum levels of brain natriuretic peptide (BNP) and echocardiography findings. Study population was divided into patients with heart failure (HF group) and patients without HF (non-HF group). Diagnostic performance of CO change under the three maneuvers was calculated by sensitivity, specificity, likelihood ratio and receiver operating characteristic (ROC) curve. RESULTS 290 patients were enrolled in the study. The final diagnosis was dyspnea due to congestive heart failure in 147 patients (50.7%). CO change with VM was the most accurate exam in identifying congestive heart failure as the cause of dyspnea with a sensitivity, specificity, positive and negative likelihood ratios of 79%, 60%, 1.97, and 0.36 respectively. Area under ROC curve was 0.62(95% CI, 0.55-0.69), 0.63(95% CI, 0.56-0.69), and 0.70(95% CI, 0.64-0.76) respectively for SP, LR, and VM. In a multivariate analysis, CO change with VM, but not with SP or LR, carried independent diagnostic value (p < 0.001). CONCLUSION the diagnosis of HF can be aided with use of analyzing the effect of VM on non-invasively measured CO among patients admitted to the ED with undifferentiated dyspnea. Diagnostic yield of SP and LR was poor.
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Affiliation(s)
- Khaoula Bel Haj Ali
- Emergency Department, Fattouma Bourguiba University Hospital, 5000 Monastir, Tunisia; Research Laboratory LR12SP18, University of Monastir, 5019, Tunisia.
| | - Adel Sekma
- Emergency Department, Fattouma Bourguiba University Hospital, 5000 Monastir, Tunisia; Research Laboratory LR12SP18, University of Monastir, 5019, Tunisia
| | - Mohamed Amine Msolli
- Emergency Department, Fattouma Bourguiba University Hospital, 5000 Monastir, Tunisia; Research Laboratory LR12SP18, University of Monastir, 5019, Tunisia
| | - Nasri Bezouich
- Emergency Department, Fattouma Bourguiba University Hospital, 5000 Monastir, Tunisia; Research Laboratory LR12SP18, University of Monastir, 5019, Tunisia
| | - Imen Gannoun
- Research Laboratory LR12SP18, University of Monastir, 5019, Tunisia
| | - Mohamed Habib Grissa
- Emergency Department, Fattouma Bourguiba University Hospital, 5000 Monastir, Tunisia; Research Laboratory LR12SP18, University of Monastir, 5019, Tunisia
| | - Hamdi Boubaker
- Emergency Department, Fattouma Bourguiba University Hospital, 5000 Monastir, Tunisia; Research Laboratory LR12SP18, University of Monastir, 5019, Tunisia
| | - Kaouthar Beltaief
- Emergency Department, Fattouma Bourguiba University Hospital, 5000 Monastir, Tunisia; Research Laboratory LR12SP18, University of Monastir, 5019, Tunisia
| | - Zohra Dridi
- Cardiology Department, Fattouma Bourguiba University Hospital, 5000 Monastir, Tunisia
| | - Semir Nouira
- Emergency Department, Fattouma Bourguiba University Hospital, 5000 Monastir, Tunisia; Research Laboratory LR12SP18, University of Monastir, 5019, Tunisia
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22
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Jayne RK, Karakan MÇ, Zhang K, Pierce N, Michas C, Bishop DJ, Chen CS, Ekinci KL, White AE. Direct laser writing for cardiac tissue engineering: a microfluidic heart on a chip with integrated transducers. LAB ON A CHIP 2021; 21:1724-1737. [PMID: 33949395 DOI: 10.1039/d0lc01078b] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
We have developed a microfluidic platform for engineering cardiac microtissues in highly-controlled microenvironments. The platform is fabricated using direct laser writing (DLW) lithography and soft lithography, and contains four separate devices. Each individual device houses a cardiac microtissue and is equipped with an integrated strain actuator and a force sensor. Application of external pressure waves to the platform results in controllable time-dependent forces on the microtissues. Conversely, oscillatory forces generated by the microtissues are transduced into measurable electrical outputs. We demonstrate the capabilities of this platform by studying the response of cardiac microtissues derived from human induced pluripotent stem cells (hiPSC) under prescribed mechanical loading and pacing. This platform will be used for fundamental studies and drug screening on cardiac microtissues.
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Affiliation(s)
- Rachael K Jayne
- Department of Mechanical Engineering, Boston University, Boston, MA 02215, USA. and Photonics Center, Boston University, Boston, MA 02215, USA
| | - M Çağatay Karakan
- Department of Mechanical Engineering, Boston University, Boston, MA 02215, USA. and Photonics Center, Boston University, Boston, MA 02215, USA
| | - Kehan Zhang
- Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA and Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA 02115, USA
| | - Noelle Pierce
- Photonics Center, Boston University, Boston, MA 02215, USA
| | - Christos Michas
- Photonics Center, Boston University, Boston, MA 02215, USA and Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA
| | - David J Bishop
- Department of Mechanical Engineering, Boston University, Boston, MA 02215, USA. and Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA and Division of Materials Science and Engineering, Boston University, Boston, Massachusetts 02215, USA and Department of Electrical and Computer Engineering, Boston University, Boston, MA 02215, USA and Department of Physics, Boston University, Boston, MA 02215, USA
| | - Christopher S Chen
- Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA and Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA 02115, USA
| | - Kamil L Ekinci
- Department of Mechanical Engineering, Boston University, Boston, MA 02215, USA. and Photonics Center, Boston University, Boston, MA 02215, USA and Division of Materials Science and Engineering, Boston University, Boston, Massachusetts 02215, USA
| | - Alice E White
- Department of Mechanical Engineering, Boston University, Boston, MA 02215, USA. and Photonics Center, Boston University, Boston, MA 02215, USA and Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA and Division of Materials Science and Engineering, Boston University, Boston, Massachusetts 02215, USA and Department of Physics, Boston University, Boston, MA 02215, USA
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23
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Stress-dependent activation of myosin in the heart requires thin filament activation and thick filament mechanosensing. Proc Natl Acad Sci U S A 2021; 118:2023706118. [PMID: 33850019 PMCID: PMC8072254 DOI: 10.1073/pnas.2023706118] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
The efficiency of the heart as a pump depends on an autoregulatory mechanism, the Frank–Starling law of the heart, that potentiates the strength of contraction in response to an increase in ventricular filling. Disruption of this mechanism compromises the ability of the heart to pump blood, potentially leading to heart failure. We used fluorescent probes on myosin in heart muscle cells to investigate the molecular basis of the Frank–Starling mechanism. Our results show that the stronger contraction of heart muscle at longer lengths is due to a calcium-dependent interfilament signaling pathway that links stress sensing in the myosin-containing filaments with calcium activation of the actin-containing filaments. This pathway can potentially be targeted for treating heart failure. Myosin-based regulation in the heart muscle modulates the number of myosin motors available for interaction with calcium-regulated thin filaments, but the signaling pathways mediating the stronger contraction triggered by stretch between heartbeats or by phosphorylation of the myosin regulatory light chain (RLC) remain unclear. Here, we used RLC probes in demembranated cardiac trabeculae to investigate the molecular structural basis of these regulatory pathways. We show that in relaxed trabeculae at near-physiological temperature and filament lattice spacing, the RLC-lobe orientations are consistent with a subset of myosin motors being folded onto the filament surface in the interacting-heads motif seen in isolated filaments. The folded conformation of myosin is disrupted by cooling relaxed trabeculae, similar to the effect induced by maximal calcium activation. Stretch or increased RLC phosphorylation in the physiological range have almost no effect on RLC conformation at a calcium concentration corresponding to that between beats. These results indicate that in near-physiological conditions, the folded myosin motors are not directly switched on by RLC phosphorylation or by the titin-based passive tension at longer sarcomere lengths in the absence of thin filament activation. However, at the higher calcium concentrations that activate the thin filaments, stretch produces a delayed activation of folded myosin motors and force increase that is potentiated by RLC phosphorylation. We conclude that the increased contractility of the heart induced by RLC phosphorylation and stretch can be explained by a calcium-dependent interfilament signaling pathway involving both thin filament sensitization and thick filament mechanosensing.
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24
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Abstract
Heart failure is an epidemic disease which affects about 1% to 2% of the population worldwide. Both, the etiology and phenotype of heart failure differ largely. Following a cardiac injury (e.g., myocardial infarction, increased preload or afterload) cellular, structural and neurohumoral modulations occur that affect the phenotype being present. These processes influence the cell function among intra- as well as intercellular behavior. In consequence, activation of the sympathoadrenergic and renin-angiotensin-aldosterone-system takes place leading to adaptive mechanisms, which are accompanied by volume overload, tachycardia, dyspnoea and further deterioration of the cellular function (vicious circle). There exists no heart failure specific clinical sign; the clinical symptomatic shows progressive deterioration acutely or chronically. As a measure of cellular dysfunction, the level of neurohormones (norepinephrine) and natriuretic peptides (e.g., NT-pro BNP) increase. For the diagnosis of heart failure, noninvasive (echocardiography, NMR, NT-proBNP) and invasive (heart catheterization, biopsy) diagnostic procedures are implemented. Modulation of the activated systems by ß-blocker, ACE-inhibitors and ARNI improve outcome and symptoms in heart failure patients with left ventricular dysfunction. Interventional and surgical therapy options may be performed as well. The understanding of the underlying pathophysiology of heart failure is essential to initiate the adequate therapeutic option individually for each patient. Furthermore, prevention of cardiovascular risk factors is essential to lower the risk of heart failure.
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Affiliation(s)
- Robert H G Schwinger
- Kardiologie, Nephrologie/Hypertonie, Pneumologie, Internistische Intensivmedizin, Medizinische Klinik II, Klinikum Weiden, Weiden, Germany
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25
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Habigt MA, Gesenhues J, Ketelhut M, Hein M, Duschner P, Rossaint R, Mechelinck M. In vivo evaluation of two adaptive Starling-like control algorithms for left ventricular assist devices. ACTA ACUST UNITED AC 2020; 66:257-266. [PMID: 34062635 DOI: 10.1515/bmt-2020-0248] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Accepted: 11/01/2020] [Indexed: 11/15/2022]
Abstract
The implantation of a left ventricular assist device (LVAD) is often the only therapy in terminal heart failure (HF). However, despite technical advancements, the physical fitness of the patients is still limited. One strategy to improve the benefits of ventricular assist device therapy might be the implementation of load adaptive control strategies. Two control strategies and a constant speed controller (CS) were implemented in an acute animal model where four healthy pigs received LVAD implantations. In the first strategy (preload recruitable stroke work [SW] controller, PRS), the desired pump work was computed in relation to the end-diastolic volume. In the second strategy, the controller was programmed to keep a fixed ratio of the mean hydraulic power of the assist device to the mean hydraulic power of the left ventricle (power relation controller, PR). Preload reduction, afterload increase experiments and short-term coronary artery occlusions were conducted to test the behavior of the control strategies under variable conditions. Within the experiments, the PR controller demonstrated the best preload sensitivity. The PRS controller had the best response to an increased afterload and to a reduced ventricular contractility in terms of effectively preventing ventricular overloading and increasing VAD support. No significant differences in systemic flow were observed.
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Affiliation(s)
- Moriz A Habigt
- Anaesthesiology Clinic, University Hospital RWTH Aachen, Aachen, Germany
| | - Jonas Gesenhues
- Institute of Automatic Control, RWTH Aachen University, Aachen, Germany
| | - Maike Ketelhut
- Institute of Automatic Control, RWTH Aachen University, Aachen, Germany
| | - Marc Hein
- Anaesthesiology Clinic, University Hospital RWTH Aachen, Aachen, Germany
| | - Patrick Duschner
- Anaesthesiology Clinic, University Hospital RWTH Aachen, Aachen, Germany
| | - Rolf Rossaint
- Anaesthesiology Clinic, University Hospital RWTH Aachen, Aachen, Germany
| | - Mare Mechelinck
- Anaesthesiology Clinic, University Hospital RWTH Aachen, Aachen, Germany
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26
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Abstract
The European Society of Cardiology recently addressed the use of SGLT2 inhibitor use in the treatment of heart failure (HF). Dapagliflozin is a SGLT2 inhibitor recently approved by the US FDA for treatment of patients with HF with a reduced ejection fraction with a New York Heart Association classification of II-IV. Dapagliflozin significantly decreases the risk of worsening HF or death from cardiovascular cause compared with placebo and this risk does not differ based on the presence or absence of Type 2 diabetes. This paper aims to summarize the chemistry, pharmacodynamics and pharmacokinetics of dapagliflozin; and evaluates the clinical efficacy of dapagliflozin in the treatment of HF.
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Affiliation(s)
- Sara Sotirakos
- Trinity College Dublin, School of Medicine, Dublin 2, Ireland
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27
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Groen M, López-Dávila AJ, Zittrich S, Pfitzer G, Stehle R. Hypertrophic and Dilated Cardiomyopathy-Associated Troponin T Mutations R130C and ΔK210 Oppositely Affect Length-Dependent Calcium Sensitivity of Force Generation. Front Physiol 2020; 11:516. [PMID: 32581830 PMCID: PMC7283609 DOI: 10.3389/fphys.2020.00516] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Accepted: 04/27/2020] [Indexed: 11/25/2022] Open
Abstract
Length-dependent activation of calcium-dependent myocardial force generation provides the basis for the Frank-Starling mechanism. To directly compare the effects of mutations associated with hypertrophic cardiomyopathy and dilated cardiomyopathy, the native troponin complex in skinned trabecular fibers of guinea pigs was exchanged with recombinant heterotrimeric, human, cardiac troponin complexes containing different human cardiac troponin T subunits (hcTnT): hypertrophic cardiomyopathy-associated hcTnTR130C, dilated cardiomyopathy-associated hcTnTΔK210 or the wild type hcTnT (hcTnTWT) serving as control. Force-calcium relations of exchanged fibers were explored at short fiber length defined as 110% of slack length (L0) and long fiber length defined as 125% of L0 (1.25 L0). At short fiber length (1.1 L0), calcium sensitivity of force generation expressed by −log [Ca2+] required for half-maximum force generation (pCa50) was highest for the hypertrophic cardiomyopathy-associated mutation R130C (5.657 ± 0.019), intermediate for the wild type control (5.580 ± 0.028) and lowest for the dilated cardiomyopathy-associated mutation ΔK210 (5.325 ± 0.038). Lengthening fibers from 1.1 L0 to 1.25 L0 increased calcium sensitivity in fibers containing hcTnTR130C (delta-pCa50 = +0.030 ± 0.010), did not alter calcium sensitivity in the wild type control (delta-pCa50 = −0.001 ± 0.010), and decreased calcium sensitivity in fibers containing hcTnTΔK210 (delta-pCa50 = −0.034 ± 0.013). Length-dependent activation indicated by the delta-pCa50 was highly significantly (P < 0.001) different between the two mutations. We hypothesize that primary effects of mutations on length-dependent activation contribute to the development of the diverging phenotypes in hypertrophic and dilated cardiomyopathy.
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Affiliation(s)
- Marcel Groen
- Department of Neurology and Neurogeriatry, Johannes Wesling Medical Center, Ruhr-University Bochum, Bochum, Germany
| | | | - Stefan Zittrich
- Institute of Vegetative Physiology, University of Cologne, Cologne, Germany
| | - Gabriele Pfitzer
- Institute of Neurophysiology, University of Cologne, Cologne, Germany
| | - Robert Stehle
- Institute of Vegetative Physiology, University of Cologne, Cologne, Germany
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28
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Saito S, Toda K, Miyagawa S, Yoshikawa Y, Hata H, Yoshioka D, Sera F, Nakamoto K, Daimon T, Sakata Y, Sawa Y. Recovery From Exhaustion of the Frank-Starling Mechanism by Mechanical Unloading With a Continuous-Flow Ventricular Assist Device. Circ J 2020; 84:1124-1131. [PMID: 32461540 DOI: 10.1253/circj.cj-20-0070] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
BACKGROUND We describe our original left ventricular assist device (LVAD) speed ramp and volume loading test designed to evaluate native heart function under continuous-flow LVAD support.Methods and Results:LVAD speed was decreased in 4 stages from the patient's optimal speed to the minimum setting for each device. Under minimal LVAD support, patients were subjected to saline loading (body weight [kg]×10 mL in 15 min). Echocardiographic and hemodynamic data were obtained at each stage of the LVAD speed ramp and every 3 min during saline loading. Patients were divided into Recovery (with successful LVAD removal; n=8) and Non-recovery (others; n=31) groups. During testing, increased pulmonary capillary wedge pressure caused by volume loading was milder in the Recovery than Non-recovery group (repeated measures analysis of variance; group effect, P=0.0069; time effect, P<0.0001; interaction effect, P=0.0173). Increased cardiac output from volume loading was significantly higher in the Recovery than Non-recovery group (group effect, P=0.0124; time effect, P<0.0001; interaction effect, P=0.0091). Therefore, the Frank-Starling curve of the Recovery group was located upward and to the left of that of the Non-recovery group. CONCLUSIONS The LVAD speed ramp and volume loading test facilitates the precise evaluation of native heart function during continuous-flow LVAD support.
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Affiliation(s)
- Shunsuke Saito
- Department of Cardiovascular Surgery, Fukui Cardiovascular Center
| | - Koichi Toda
- Department of Cardiovascular Surgery, Osaka University Graduate School of Medicine
| | - Shigeru Miyagawa
- Department of Cardiovascular Surgery, Osaka University Graduate School of Medicine
| | - Yasushi Yoshikawa
- Department of Cardiovascular Surgery, Osaka University Graduate School of Medicine
| | - Hiroki Hata
- Department of Cardiovascular Surgery, Osaka University Graduate School of Medicine
| | - Daisuke Yoshioka
- Department of Cardiovascular Surgery, Osaka University Graduate School of Medicine
| | - Fusako Sera
- Department of Cardiovascular Medicine, Osaka University Graduate School of Medicine
| | - Kei Nakamoto
- Department of Cardiovascular Medicine, Osaka University Graduate School of Medicine
| | | | - Yasushi Sakata
- Department of Cardiovascular Medicine, Osaka University Graduate School of Medicine
| | - Yoshiki Sawa
- Department of Cardiovascular Surgery, Osaka University Graduate School of Medicine
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29
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McDonald KS, Hanft LM, Robinett JC, Guglin M, Campbell KS. Regulation of Myofilament Contractile Function in Human Donor and Failing Hearts. Front Physiol 2020; 11:468. [PMID: 32523542 PMCID: PMC7261867 DOI: 10.3389/fphys.2020.00468] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Accepted: 04/16/2020] [Indexed: 01/14/2023] Open
Abstract
Heart failure (HF) often includes changes in myocardial contractile function. This study addressed the myofibrillar basis for contractile dysfunction in failing human myocardium. Regulation of contractile properties was measured in cardiac myocyte preparations isolated from frozen, left ventricular mid-wall biopsies of donor (n = 7) and failing human hearts (n = 8). Permeabilized cardiac myocyte preparations were attached between a force transducer and a position motor, and both the Ca2+ dependence and sarcomere length (SL) dependence of force, rate of force, loaded shortening, and power output were measured at 15 ± 1°C. The myocyte preparation size was similar between groups (donor: length 148 ± 10 μm, width 21 ± 2 μm, n = 13; HF: length 131 ± 9 μm, width 23 ± 1 μm, n = 16). The maximal Ca2+-activated isometric force was also similar between groups (donor: 47 ± 4 kN⋅m-2; HF: 44 ± 5 kN⋅m-2), which implicates that previously reported force declines in multi-cellular preparations reflect, at least in part, tissue remodeling. Maximal force development rates were also similar between groups (donor: k tr = 0.60 ± 0.05 s-1; HF: k tr = 0.55 ± 0.04 s-1), and both groups exhibited similar Ca2+ activation dependence of k tr values. Human cardiac myocyte preparations exhibited a Ca2+ activation dependence of loaded shortening and power output. The peak power output normalized to isometric force (PNPO) decreased by ∼12% from maximal Ca2+ to half-maximal Ca2+ activations in both groups. Interestingly, the SL dependence of PNPO was diminished in failing myocyte preparations. During sub-maximal Ca2+ activation, a reduction in SL from ∼2.25 to ∼1.95 μm caused a ∼26% decline in PNPO in donor myocytes but only an ∼11% change in failing myocytes. These results suggest that altered length-dependent regulation of myofilament function impairs ventricular performance in failing human hearts.
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Affiliation(s)
- Kerry S. McDonald
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, MO, United States
| | - Laurin M. Hanft
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, MO, United States
| | - Joel C. Robinett
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, MO, United States
| | - Maya Guglin
- Division of Cardiovascular Medicine, University of Kentucky, Lexington, KY, United States
| | - Kenneth S. Campbell
- Division of Cardiovascular Medicine, University of Kentucky, Lexington, KY, United States
- Department of Physiology, University of Kentucky, Lexington, KY, United States
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30
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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: 16] [Impact Index Per Article: 4.0] [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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31
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Balakina-Vikulova NA, Panfilov A, Solovyova O, Katsnelson LB. Mechano-calcium and mechano-electric feedbacks in the human cardiomyocyte analyzed in a mathematical model. J Physiol Sci 2020; 70:12. [PMID: 32070290 PMCID: PMC7028825 DOI: 10.1186/s12576-020-00741-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Accepted: 02/04/2020] [Indexed: 12/11/2022]
Abstract
Experiments on animal hearts (rat, rabbit, guinea pig, etc.) have demonstrated that mechano-calcium feedback (MCF) and mechano-electric feedback (MEF) are very important for myocardial self-regulation because they adjust the cardiomyocyte contractile function to various mechanical loads and to mechanical interactions between heterogeneous myocardial segments in the ventricle walls. In in vitro experiments on these animals, MCF and MEF manifested themselves in several basic classical phenomena (e.g., load dependence, length dependence of isometric twitches, etc.), and in the respective responses of calcium transients and action potentials. However, it is extremely difficult to study simultaneously the electrical, calcium, and mechanical activities of the human heart muscle in vitro. Mathematical modeling is a useful tool for exploring these phenomena. We have developed a novel model to describe electromechanical coupling and mechano-electric feedbacks in the human cardiomyocyte. It combines the ‘ten Tusscher–Panfilov’ electrophysiological model of the human cardiomyocyte with our module of myocardium mechanical activity taken from the ‘Ekaterinburg–Oxford’ model and adjusted to human data. Using it, we simulated isometric and afterloaded twitches and effects of MCF and MEF on excitation–contraction coupling. MCF and MEF were found to affect significantly the duration of the calcium transient and action potential in the human cardiomyocyte model in response to both smaller afterloads as compared to bigger ones and various mechanical interventions applied during isometric and afterloaded twitches.
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Affiliation(s)
- Nathalie A Balakina-Vikulova
- Institute of Immunology and Physiology of the Ural Branch of the Russian Academy of Sciences, Ekaterinburg, Russia. .,Ural Federal University, Ekaterinburg, Russia.
| | - Alexander Panfilov
- Ural Federal University, Ekaterinburg, Russia.,Ghent University, Ghent, Belgium
| | - Olga Solovyova
- Institute of Immunology and Physiology of the Ural Branch of the Russian Academy of Sciences, Ekaterinburg, Russia.,Ural Federal University, Ekaterinburg, Russia
| | - Leonid B Katsnelson
- Institute of Immunology and Physiology of the Ural Branch of the Russian Academy of Sciences, Ekaterinburg, Russia.,Ural Federal University, Ekaterinburg, Russia
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32
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Pitoulis FG, Terracciano CM. Heart Plasticity in Response to Pressure- and Volume-Overload: A Review of Findings in Compensated and Decompensated Phenotypes. Front Physiol 2020; 11:92. [PMID: 32116796 PMCID: PMC7031419 DOI: 10.3389/fphys.2020.00092] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Accepted: 01/27/2020] [Indexed: 12/20/2022] Open
Abstract
The adult human heart has an exceptional ability to alter its phenotype to adapt to changes in environmental demand. This response involves metabolic, mechanical, electrical, and structural alterations, and is known as cardiac plasticity. Understanding the drivers of cardiac plasticity is essential for development of therapeutic agents. This is particularly important in contemporary cardiology, which uses treatments with peripheral effects (e.g., on kidneys, adrenal glands). This review focuses on the effects of different hemodynamic loads on myocardial phenotype. We examine mechanical scenarios of pressure- and volume overload, from the initial insult, to compensated, and ultimately decompensated stage. We discuss how different hemodynamic conditions occur and are underlined by distinct phenotypic and molecular changes. We complete the review by exploring how current basic cardiac research should leverage available cardiac models to study mechanical load in its different presentations.
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33
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Reda SM, Chandra M. Dilated cardiomyopathy mutation (R174W) in troponin T attenuates the length-mediated increase in cross-bridge recruitment and myofilament Ca 2+ sensitivity. Am J Physiol Heart Circ Physiol 2019; 317:H648-H657. [PMID: 31373515 DOI: 10.1152/ajpheart.00171.2019] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Alterations in length-dependent activation (LDA) may constitute a mechanism by which cardiomyopathy mutations lead to deleterious phenotypes and compromised heart function, because LDA underlies the molecular basis by which the heart tunes myocardial force production on a beat-to-beat basis (Frank-Starling mechanism). In this study, we investigated the effect of DCM-linked mutation (R173W) in human cardiac troponin T (TnT) on myofilament LDA. R173W mutation is associated with left ventricular dilatation and systolic dysfunction and is found in multiple families. R173W mutation is in the central region (residues 80-180) of TnT, which is known to be important for myofilament cooperativity and cross-bridge (XB) recruitment. Steady-state and dynamic contractile parameters were measured in detergent-skinned guinea pig left ventricular muscle fibers reconstituted with recombinant guinea pig wild-type TnT (TnTWT) or mutant TnT (TnTR174W; guinea pig analog of human R173W mutation) at two different sarcomere lengths (SL): short (1.9 µm) and long (2.3 µm). TnTR174W decreased pCa50 (-log [Ca2+]free required for half-maximal activation) to a greater extent at long than at short SL; for example, pCa50 decreased by 0.12 pCa units at long SL and by 0.06 pCa units at short SL. Differential changes in pCa50 at short and long SL attenuated the SL-dependent increase in myofilament Ca2+ sensitivity (ΔpCa50) in TnTR174W fibers; ΔpCa50 was 0.10 units in TnTWT fibers but only 0.04 units in TnTR174W fibers. Furthermore, TnTR174W blunted the SL-dependent increase in the magnitude of XB recruitment. Our observations suggest that the R173W mutation in human cardiac TnT may impair Frank-Starling mechanism.NEW & NOTEWORTHY This work characterizes the effect of dilated cardiomyopathy mutation in cardiac troponin T (TnTR174W) on myofilament length-dependent activation. TnTR174W attenuates the length-dependent increase in cross-bridge recruitment and myofilament Ca2+ sensitivity.
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Affiliation(s)
- Sherif M Reda
- Department of Integrative Physiology and Neuroscience, Washington State University, Pullman, Washington
| | - Murali Chandra
- Department of Integrative Physiology and Neuroscience, Washington State University, Pullman, Washington
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Garg V, Verma S, Connelly K. Mechanistic insights regarding the role of SGLT2 inhibitors and GLP1 agonist drugs on cardiovascular disease in diabetes. Prog Cardiovasc Dis 2019; 62:349-357. [PMID: 31381891 DOI: 10.1016/j.pcad.2019.07.005] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Accepted: 07/19/2019] [Indexed: 12/22/2022]
Abstract
The treatment landscape for patients with established or at high risk for cardiovascular disease and type 2 diabetes mellitus has entirely changed over the past decade, with the introduction of several anti-hyperglycemic agents. Sodium-glucose cotransporter 2 (SGLT2) inhibitors and glucagon-like peptide-1 (GLP-1) agonists are two anti-hyperglycemic classes which have been of special interest after multiple large cardiovascular disease (CVD) outcomes studies have demonstrated superiority of these agents compared to placebo for major adverse CVD events and in some cases, hospitalization for heart failure. Despite the dramatic results of these trials, only recently have we began to understand the mechanisms underlying these CVD benefits. Here we review the underlying mechanisms which have the greatest plausibility for both of these agents including the impact of ventricular loading conditions, direct effects on cardiac structure and function, myocardial energetics and sodium/hydrogen exchange for SGLT2 inhibitors, and the anti-atherosclerotic, anti-inflammatory, and modulation of endothelial function for GLP-1 agonists.
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Affiliation(s)
- Vinay Garg
- Division of Cardiology, St. Michael's Hospital, Toronto, ON, Canada; Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON, Canada
| | - Subodh Verma
- Division of Cardiac Surgery, St. Michael's Hospital, Toronto, ON, Canada; Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON, Canada
| | - Kim Connelly
- Division of Cardiology, St. Michael's Hospital, Toronto, ON, Canada; Department of Physiology, University of Toronto, Toronto, ON, Canada; Keenan Research Centre at the Li Ka Shing Knowledge Institute of St Michael's Hospital, Toronto, ON, Canada.
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35
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Sato Y, Yoshihisa A, Oikawa M, Nagai T, Yoshikawa T, Saito Y, Yamamoto K, Takeishi Y, Anzai T. Relation of Systolic Blood Pressure on the Following Day with Post-Discharge Mortality in Hospitalized Heart Failure Patients with Preserved Ejection Fraction. Int Heart J 2019; 60:876-885. [PMID: 31257340 DOI: 10.1536/ihj.18-699] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The clinical scenario, which is based on systolic blood pressure (SBP) upon admission, is useful for classifying and determining initial treatment for acute heart failure (HF). However, the prognostic significance of SBP following the initial treatment is unclear.The Japanese Heart Failure Syndrome with Preserved Ejection Fraction (JASPER) registry is a nationwide, observational, and prospective registration of consecutive Japanese patients hospitalized with HF with preserved ejection fraction (HFpEF) and left ventricular ejection fraction ≥ 50%. We divided 525 patients into three groups based on their SBP on the day following hospitalization: high (SBP > 140 mmHg, n = 72, 13.7%); normal (100 ≤ SBP ≤ 140 mmHg, n = 379, 72.2%); and low (SBP < 100 mmHg, n = 74, 14.1%) groups. This analysis had two primary endpoints: (1) all-cause death and (2) all-cause death or rehospitalization for HF. In the Kaplan-Meier analysis, both of the endpoints were the highest in the low group (Log-Rank < 0.05, respectively). Compared to the normal and high groups, the low group demonstrated a higher prevalence of atrial fibrillation (67.1%, 63.9%, and 47.8%, P = 0.026) and the lowest left ventricular outflow tract velocity time integral determined by echocardiography (16.4 cm, 19.4 cm, and 23.3 cm, P = 0.001). In the multivariable Cox proportional hazard analysis, low SBP on the day following hospitalization was an independent predictor of all-cause death (hazard ratio 1.868, 95% confidence interval 1.024-3.407, P = 0.042) and the composite endpoint (hazard ratio 1.660, 95% confidence interval 1.103-2.500, P = 0.015).Classification based on SBP on the day following initial treatment predicts post-discharge prognosis in hospitalized patients with HFpEF.
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Affiliation(s)
- Yu Sato
- Department of Cardiovascular Medicine, Fukushima Medical University
| | - Akiomi Yoshihisa
- Department of Cardiovascular Medicine, Fukushima Medical University
| | - Masayoshi Oikawa
- Department of Cardiovascular Medicine, Fukushima Medical University
| | - Toshiyuki Nagai
- Department of Cardiovascular Medicine, Hokkaido University Graduate School of Medicine
| | | | - Yoshihiko Saito
- First Department of Internal Medicine, Nara Medical University
| | - Kazuhiro Yamamoto
- Department of Molecular Medicine and Therapeutics, Faculty of Medicine, Tottori University
| | | | - Toshihisa Anzai
- Department of Cardiovascular Medicine, Hokkaido University Graduate School of Medicine
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36
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Rodrigues PG, Miranda-Silva D, Costa SM, Barros C, Hamdani N, Moura C, Mendes MJ, Sousa-Mendes C, Trindade F, Fontoura D, Vitorino R, Linke WA, Leite-Moreira AF, Falcão-Pires I. Early myocardial changes induced by doxorubicin in the nonfailing dilated ventricle. Am J Physiol Heart Circ Physiol 2019; 316:H459-H475. [DOI: 10.1152/ajpheart.00401.2018] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Several studies have demonstrated that administration of doxorubicin (DOXO) results in cardiotoxicity, which eventually progresses to dilated cardiomyopathy. The present work aimed to evaluate the early myocardial changes of DOXO-induced cardiotoxicity. Male New Zealand White rabbits were injected intravenously with DOXO twice weekly for 8 wk [DOXO-induced heart failure (DOXO-HF)] or with an equivolumetric dose of saline (control). Echocardiographic evaluation was performed, and myocardial samples were collected to evaluate myocardial cellular and molecular modifications. The DOXO-HF group presented cardiac hypertrophy and higher left ventricular cavity diameters, showing a dilated phenotype but preserved ejection fraction. Concerning cardiomyocyte function, the DOXO-HF group presented a trend toward increased active tension without significant differences in passive tension. The myocardial GSSG-to-GSH ratio and interstitial fibrosis were increased and Bax-to- Bcl-2 ratio presented a trend toward an increase, suggesting the activation of apoptosis signaling pathways. The macromolecule titin shifted toward the more compliant isoform (N2BA), whereas the stiffer one (N2B) was shown to be hypophosphorylated. Differential protein analysis from the aggregate-enriched fraction through gel liquid chromatography-tandem mass spectrometry revealed an increase in the histidine-rich glycoprotein fragment in DOXO-HF animals. This work describes novel and early myocardial effects of DOXO-induced cardiotoxicity. Thus, tracking these changes appears to be of extreme relevance for the early detection of cardiac damage (as soon as ventricular dilation becomes evident) before irreversible cardiac function deterioration occurs (reduced ejection fraction). Moreover, it allows for the adjustment of the therapeutic approach and thus the prevention of cardiomyopathy progression. NEW & NOTEWORTHY Identification of early myocardial effects of doxorubicin in the heart is essential to hinder the development of cardiac complications and adjust the therapeutic approach. This study describes doxorubicin-induced cellular and molecular modifications before the onset of dilated cardiomyopathy. Myocardial samples from doxorubicin-treated rabbits showed a tendency for higher cardiomyocyte active tension, titin isoform shift from N2B to N2BA, hypophosphorylation of N2B, increased apoptotic genes, left ventricular interstitial fibrosis, and increased aggregation of histidine-rich glycoprotein.
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Affiliation(s)
- Patricia G. Rodrigues
- Department of Surgery and Physiology, Faculty of Medicine, Unidade de Investigação Cardiovascular, Universidade do Porto, Porto, Portugal
| | - Daniela Miranda-Silva
- Department of Surgery and Physiology, Faculty of Medicine, Unidade de Investigação Cardiovascular, Universidade do Porto, Porto, Portugal
| | - Sofia M. Costa
- Department of Surgery and Physiology, Faculty of Medicine, Unidade de Investigação Cardiovascular, Universidade do Porto, Porto, Portugal
| | - Carla Barros
- Department of Surgery and Physiology, Faculty of Medicine, Unidade de Investigação Cardiovascular, Universidade do Porto, Porto, Portugal
| | - Nazha Hamdani
- Department of Systems Physiology, Ruhr University, Bochum, Germany
| | - Cláudia Moura
- Department of Surgery and Physiology, Faculty of Medicine, Unidade de Investigação Cardiovascular, Universidade do Porto, Porto, Portugal
| | - Maria J. Mendes
- Department of Surgery and Physiology, Faculty of Medicine, Unidade de Investigação Cardiovascular, Universidade do Porto, Porto, Portugal
| | - Cláudia Sousa-Mendes
- Department of Surgery and Physiology, Faculty of Medicine, Unidade de Investigação Cardiovascular, Universidade do Porto, Porto, Portugal
| | - Fábio Trindade
- Department of Surgery and Physiology, Faculty of Medicine, Unidade de Investigação Cardiovascular, Universidade do Porto, Porto, Portugal
- Department of Medical Sciences, Institute of Biomedicine, University of Aveiro, Aveiro, Portugal
| | - Dulce Fontoura
- Department of Surgery and Physiology, Faculty of Medicine, Unidade de Investigação Cardiovascular, Universidade do Porto, Porto, Portugal
| | - Rui Vitorino
- Department of Surgery and Physiology, Faculty of Medicine, Unidade de Investigação Cardiovascular, Universidade do Porto, Porto, Portugal
- Department of Medical Sciences, Institute of Biomedicine, University of Aveiro, Aveiro, Portugal
| | - Wolfgang A. Linke
- Institute of Physiology II, University of Muenster, Muenster, Germany
| | - Adelino F. Leite-Moreira
- Department of Surgery and Physiology, Faculty of Medicine, Unidade de Investigação Cardiovascular, Universidade do Porto, Porto, Portugal
- Department of Cardiothoracic Surgery, São João Hospital Centre, Porto, Portugal
| | - Inês Falcão-Pires
- Department of Surgery and Physiology, Faculty of Medicine, Unidade de Investigação Cardiovascular, Universidade do Porto, Porto, Portugal
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37
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Proposed mechanism for the length dependence of the force developed in maximally activated muscles. Sci Rep 2019; 9:1317. [PMID: 30718530 PMCID: PMC6362285 DOI: 10.1038/s41598-018-36706-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2018] [Accepted: 11/20/2018] [Indexed: 11/08/2022] Open
Abstract
The molecular bases of the Frank-Starling law of the heart and of its cellular counterpart, the length dependent activation (LDA), are largely unknown. However, the recent discovery of the thick filament activation, a second pathway beside the well-known calcium mediated thin filament activation, is promising for elucidating these mechanisms. The thick filament activation is mediated by the tension acting on it through the mechano-sensing (MS) mechanism and can be related to the LDA via the titin passive tension. Here, we propose a mechanism to explain the higher maximum tension at longer sarcomere lengths generated by a maximally activated muscle and test it in-silico with a single fiber and a ventricle model. The active tension distribution along the thick filament generates a reservoir of inactive motors at its free-end that can be activated by passive tension on a beat-to-beat timescale. The proposed mechanism is able to quantitatively account for the observed increment in tension at the fiber level, however, the ventricle model suggests that this component of the LDA is not crucial in physiological conditions.
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38
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Ahmad Bakir A, Al Abed A, Stevens MC, Lovell NH, Dokos S. A Multiphysics Biventricular Cardiac Model: Simulations With a Left-Ventricular Assist Device. Front Physiol 2018; 9:1259. [PMID: 30271353 PMCID: PMC6142745 DOI: 10.3389/fphys.2018.01259] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Accepted: 08/21/2018] [Indexed: 11/16/2022] Open
Abstract
Computational models have become essential in predicting medical device efficacy prior to clinical studies. To investigate the performance of a left-ventricular assist device (LVAD), a fully-coupled cardiac fluid-electromechanics finite element model was developed, incorporating electrical activation, passive and active myocardial mechanics, as well as blood hemodynamics solved simultaneously in an idealized biventricular geometry. Electrical activation was initiated using a simplified Purkinje network with one-way coupling to the surrounding myocardium. Phenomenological action potential and excitation-contraction equations were adapted to trigger myocardial contraction. Action potential propagation was formulated within a material frame to emulate gap junction-controlled propagation, such that the activation sequence was independent of myocardial deformation. Passive cardiac mechanics were governed by a transverse isotropic hyperelastic constitutive formulation. Blood velocity and pressure were determined by the incompressible Navier-Stokes formulations with a closed-loop Windkessel circuit governing the circulatory load. To investigate heart-LVAD interaction, we reduced the left ventricular (LV) contraction stress to mimic a failing heart, and inserted a LVAD cannula at the LV apex with continuous flow governing the outflow rate. A proportional controller was implemented to determine the pump motor voltage whilst maintaining pump motor speed. Following LVAD insertion, the model revealed a change in the LV pressure-volume loop shape from rectangular to triangular. At higher pump speeds, aortic ejection ceased and the LV decompressed to smaller end diastolic volumes. After multiple cycles, the LV cavity gradually collapsed along with a drop in pump motor current. The model was therefore able to predict ventricular collapse, indicating its utility for future development of control algorithms and pre-clinical testing of LVADs to avoid LV collapse in recipients.
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Affiliation(s)
- Azam Ahmad Bakir
- Graduate School of Biomedical Engineering, University of New South Wales, Kensington, NSW, Australia
| | - Amr Al Abed
- Graduate School of Biomedical Engineering, University of New South Wales, Kensington, NSW, Australia
| | - Michael C Stevens
- Graduate School of Biomedical Engineering, University of New South Wales, Kensington, NSW, Australia.,Innovative Cardiovascular Engineering and Technology Laboratory, Critical Care Research Group, The Prince Charles Hospital, Brisbane, QLD, Australia
| | - Nigel H Lovell
- Graduate School of Biomedical Engineering, University of New South Wales, Kensington, NSW, Australia
| | - Socrates Dokos
- Graduate School of Biomedical Engineering, University of New South Wales, Kensington, NSW, Australia
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39
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Lookin ON, Protsenko YL. Deficiency of Length-Dependent Activation of Contraction in the Cardiac Muscle of Rats with Heart Failure: Assessment of the Muscle Strip and Single Cell Levels. Biophysics (Nagoya-shi) 2018. [DOI: 10.1134/s0006350918030132] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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40
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Regnier M. Mechanistic complexity of contractile dysfunction in hypertrophic cardiomyopathy. J Gen Physiol 2018; 150:1051-1053. [PMID: 30037852 PMCID: PMC6080894 DOI: 10.1085/jgp.201812091] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Reflections on recent work providing mechanistic insight into the pathological effects of a cardiac troponin T mutation.
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41
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Corazza I, Casadei L, Bonafè E, Cercenelli L, Marcelli E, Zannoli R. How to transform a fixed stroke alternating syringe ventricle into an adjustable elastance ventricle. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2018; 89:074301. [PMID: 30068143 DOI: 10.1063/1.5030100] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Most devices used for bench simulation of the cardiovascular system are based either on a syringe-like alternating pump or an elastic chamber inside a fluid-filled rigid box. In these devices, it is very difficult to control the ventricular elastance and simulate pathologies related to the mechanical mismatch between the ventricle and arterial load (i.e., heart failure). This work presents a possible solution to transforming a syringe-like pump with a fixed ventricle into a ventricle with variable elastance. Our proposal was tested in two steps: (1) fixing the ventricle and the aorta and changing the peripheral resistance (PHR); (2) fixing the aorta and changing the ventricular elastance and the PHR. The signals of interest were acquired to build the ventricular pressure-volume (P-V) loops describing the different physiological conditions, and the end-systolic pressure-volume relationships (ESPVRs) were calculated with linear interpolation. The results obtained show a good physiological behavior of our mock for both steps. (1) Since the ventricle is the same, the systolic pressures increase and the stroke volumes decrease with the PHR: the ESPVR, obtained by interpolating the pressure and volume values at end-systolic phases, is linear. (2) Each ventricle presents ESPVR with different slopes depending on the ventricle elastance with a very good linear behavior. In conclusion, this paper demonstrates that a fixed stroke alternating syringe ventricle can be transformed into an adjustable elastance ventricle.
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Affiliation(s)
- Ivan Corazza
- Experimental, Diagnostic and Specialty Medicine Department, University of Bologna, Bologna, Italy
| | - Lorenzo Casadei
- Experimental, Diagnostic and Specialty Medicine Department, University of Bologna, Bologna, Italy
| | - Elisa Bonafè
- Experimental, Diagnostic and Specialty Medicine Department, University of Bologna, Bologna, Italy
| | - Laura Cercenelli
- Experimental, Diagnostic and Specialty Medicine Department, University of Bologna, Bologna, Italy
| | - Emanuela Marcelli
- Experimental, Diagnostic and Specialty Medicine Department, University of Bologna, Bologna, Italy
| | - Romano Zannoli
- Experimental, Diagnostic and Specialty Medicine Department, University of Bologna, Bologna, Italy
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42
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Reda SM, Chandra M. Cardiomyopathy mutation (F88L) in troponin T abolishes length dependency of myofilament Ca 2+ sensitivity. J Gen Physiol 2018; 150:809-819. [PMID: 29776992 PMCID: PMC5987878 DOI: 10.1085/jgp.201711974] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Revised: 03/09/2018] [Accepted: 04/24/2018] [Indexed: 01/14/2023] Open
Abstract
The F88L mutation in cardiac troponin T (TnTF88L) is associated with hypertrophic cardiomyopathy. Reda and Chandra reveal that it abolishes length-mediated increase in myofilament Ca2+ sensitivity and attenuates cooperative mechanisms governing length-dependent activation. Recent clinical studies have revealed a new hypertrophic cardiomyopathy–associated mutation (F87L) in the central region of human cardiac troponin T (TnT). However, despite its implication in several incidences of sudden cardiac death in young and old adults, whether F87L is associated with cardiac contractile dysfunction is unknown. Because the central region of TnT is important for modulating the muscle length–mediated recruitment of new force-bearing cross-bridges (XBs), we hypothesize that the F87L mutation causes molecular changes that are linked to the length-dependent activation of cardiac myofilaments. Length-dependent activation is important because it contributes significantly to the Frank–Starling mechanism, which enables the heart to vary stroke volume as a function of changes in venous return. We measured steady-state and dynamic contractile parameters in detergent-skinned guinea pig cardiac muscle fibers reconstituted with recombinant guinea pig wild-type TnT (TnTWT) or the guinea pig analogue (TnTF88L) of the human mutation at two different sarcomere lengths (SLs): short (1.9 µm) and long (2.3 µm). TnTF88L increases pCa50 (−log [Ca2+]free required for half-maximal activation) to a greater extent at short SL than at long SL; for example, pCa50 increases by 0.25 pCa units at short SL and 0.17 pCa units at long SL. The greater increase in pCa50 at short SL leads to the abolishment of the SL-dependent increase in myofilament Ca2+ sensitivity (ΔpCa50) in TnTF88L fibers, ΔpCa50 being 0.10 units in TnTWT fibers but only 0.02 units in TnTF88L fibers. Furthermore, at short SL, TnTF88L attenuates the negative impact of strained XBs on force-bearing XBs and augments the magnitude of muscle length–mediated recruitment of new force-bearing XBs. Our findings suggest that the TnTF88L-mediated effects on cardiac thin filaments may lead to a negative impact on the Frank–Starling mechanism.
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Affiliation(s)
- Sherif M Reda
- Department of Integrative Physiology and Neuroscience, Washington State University, Pullman, WA
| | - Murali Chandra
- Department of Integrative Physiology and Neuroscience, Washington State University, Pullman, WA
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Wang Z, Patel JR, Schreier DA, Hacker TA, Moss RL, Chesler NC. Organ-level right ventricular dysfunction with preserved Frank-Starling mechanism in a mouse model of pulmonary arterial hypertension. J Appl Physiol (1985) 2018; 124:1244-1253. [PMID: 29369739 PMCID: PMC6008075 DOI: 10.1152/japplphysiol.00725.2017] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Revised: 01/08/2018] [Accepted: 01/22/2018] [Indexed: 01/08/2023] Open
Abstract
Pulmonary arterial hypertension (PAH) is a rapidly fatal disease in which mortality is due to right ventricular (RV) failure. It is unclear whether RV dysfunction initiates at the organ level or the subcellular level or both. We hypothesized that chronic pressure overload-induced RV dysfunction begins at the organ level with preserved Frank-Starling mechanism in myocytes. To test this hypothesis, we induced PAH with Sugen + hypoxia (HySu) in mice and measured RV whole organ and subcellular functional changes by in vivo pressure-volume measurements and in vitro trabeculae length-tension measurements, respectively, at multiple time points for up to 56 days. We observed progressive changes in RV function at the organ level: in contrast to early PAH (14-day HySu), in late PAH (56-day HySu) ejection fraction and ventricular-vascular coupling were decreased. At the subcellular level, direct measurements of myofilament contraction showed that RV contractile force was similarly increased at any stage of PAH development. Moreover, cross-bridge kinetics were not changed and length dependence of force development (Frank-Starling relation) were not different from baseline in any PAH group. Histological examinations confirmed increased cardiomyocyte cross-sectional area and decreased von Willebrand factor expression in RVs with PAH. In summary, RV dysfunction developed at the organ level with preserved Frank-Starling mechanism in myofilaments, and these results provide novel insight into the development of RV dysfunction, which is critical to understanding the mechanisms of RV failure. NEW & NOTEWORTHY A multiscale investigation of pulmonary artery pressure overload in mice showed time-dependent organ-level right ventricular (RV) dysfunction with preserved Frank-Starling relations in myofilaments. Our findings provide novel insight into the development of RV dysfunction, which is critical to understanding mechanisms of RV failure.
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Affiliation(s)
- Zhijie Wang
- Department of Biomedical Engineering, University of Wisconsin-Madison , Madison, Wisconsin
- Department of Mechanical Engineering, Colorado State University , Fort Collins, Colorado
| | - Jitandrakumar R Patel
- Department of Cell and Regenerative Biology, University of Wisconsin-Madison , Madison, Wisconsin
| | - David A Schreier
- Department of Biomedical Engineering, University of Wisconsin-Madison , Madison, Wisconsin
| | - Timothy A Hacker
- Department of Medicine, University of Wisconsin-Madison , Madison, Wisconsin
| | - Richard L Moss
- Department of Cell and Regenerative Biology, University of Wisconsin-Madison , Madison, Wisconsin
| | - Naomi C Chesler
- Department of Biomedical Engineering, University of Wisconsin-Madison , Madison, Wisconsin
- Department of Medicine, University of Wisconsin-Madison , Madison, Wisconsin
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Gollapudi SK, Reda SM, Chandra M. Omecamtiv Mecarbil Abolishes Length-Mediated Increase in Guinea Pig Cardiac Myofiber Ca 2+ Sensitivity. Biophys J 2017; 113:880-888. [PMID: 28834724 DOI: 10.1016/j.bpj.2017.07.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Revised: 06/19/2017] [Accepted: 07/05/2017] [Indexed: 01/14/2023] Open
Abstract
Omecamtiv mecarbil (OM) is a pharmacological agent that augments cardiac contractile function by enhancing myofilament Ca2+ sensitivity. Given that interventions that increase myofilament Ca2+ sensitivity have the potential to alter length-dependent activation (LDA) of cardiac myofilaments, we tested the influence of OM on this fundamental property of the heart. This is significant not only because LDA is prominent in cardiac muscle but also because it contributes to the Frank-Starling law, a mechanism by which the heart increases stroke volume in response to an increase in venous return. We measured steady-state and dynamic contractile indices in detergent-skinned guinea pig (Cavia porcellus) cardiac muscle fibers in the absence and presence of 0.3 and 3.0 μM OM at two different sarcomere lengths (SLs), short SL (1.9 μm) and long SL (2.3 μm). Myofilament Ca2+ sensitivity, as measured by pCa50 (-log of [Ca2+]free concentration required for half-maximal activation), increased significantly at both short and long SLs in OM-treated fibers when compared to untreated fibers; however, the magnitude of increase in pCa50 was twofold greater at short SL than at long SL. A consequence of this greater increase in pCa50 at short SL was that pCa50 did not increase any further at long SL, suggesting that OM abolished the SL dependency of pCa50. Furthermore, the SL dependency of rate constants of cross-bridge distortion dynamics (c) and force redevelopment (ktr) was abolished in 0.3-μM-OM-treated fibers. The negative impact of OM on the SL dependency of pCa50, c, and ktr was also observed in 3.0-μM-OM-treated fibers, indicating that cooperative mechanisms linked to LDA were altered by the OM-mediated effects on cardiac myofilaments.
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Affiliation(s)
- Sampath K Gollapudi
- Department of Integrative Physiology and Neuroscience (IPN), Washington State University, Pullman, Washington
| | - Sherif M Reda
- Department of Integrative Physiology and Neuroscience (IPN), Washington State University, Pullman, Washington
| | - Murali Chandra
- Department of Integrative Physiology and Neuroscience (IPN), Washington State University, Pullman, Washington.
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Crosby JR, DeCook KJ, Tran PL, Betterton E, Smith RG, Larson DF, Khalpey ZI, Burkhof D, Slepian MJ. A Physical Heart Failure Simulation System Utilizing the Total Artificial Heart and Modified Donovan Mock Circulation. Artif Organs 2017; 41:E52-E65. [PMID: 27935084 PMCID: PMC5466504 DOI: 10.1111/aor.12808] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2016] [Revised: 06/21/2016] [Accepted: 06/30/2016] [Indexed: 01/11/2023]
Abstract
With the growth and diversity of mechanical circulatory support (MCS) systems entering clinical use, a need exists for a robust mock circulation system capable of reliably emulating and reproducing physiologic as well as pathophysiologic states for use in MCS training and inter-device comparison. We report on the development of such a platform utilizing the SynCardia Total Artificial Heart and a modified Donovan Mock Circulation System, capable of being driven at normal and reduced output. With this platform, clinically relevant heart failure hemodynamics could be reliably reproduced as evidenced by elevated left atrial pressure (+112%), reduced aortic flow (-12.6%), blunted Starling-like behavior, and increased afterload sensitivity when compared with normal function. Similarly, pressure-volume relationships demonstrated enhanced sensitivity to afterload and decreased Starling-like behavior in the heart failure model. Lastly, the platform was configured to allow the easy addition of a left ventricular assist device (HeartMate II at 9600 RPM), which upon insertion resulted in improvement of hemodynamics. The present configuration has the potential to serve as a viable system for training and research, aimed at fostering safe and effective MCS device use.
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Affiliation(s)
- Jessica R. Crosby
- Biomedical Engineering GIDP, University of Arizona, Tucson, Arizona 85724
| | - Katrina J. DeCook
- Biomedical Engineering GIDP, University of Arizona, Tucson, Arizona 85724
| | - Phat L. Tran
- Biomedical Engineering GIDP, University of Arizona, Tucson, Arizona 85724
- Department of Medicine, Sarver Heart Center, University of Arizona, Tucson, Arizona 85724 43Artificial Heart Department, Banner University Medical Center, University of Arizona, Tucson, Arizona 85724
| | | | - Richard G. Smith
- Biomedical Engineering GIDP, University of Arizona, Tucson, Arizona 85724
- Department of Medicine, Sarver Heart Center, University of Arizona, Tucson, Arizona 85724 43Artificial Heart Department, Banner University Medical Center, University of Arizona, Tucson, Arizona 85724
- Department of Surgery, University of Arizona, Tucson, AZ 85724
| | | | - Zain I. Khalpey
- Department of Surgery, University of Arizona, Tucson, AZ 85724
| | | | - Marvin J. Slepian
- Biomedical Engineering GIDP, University of Arizona, Tucson, Arizona 85724
- Department of Biomedical Engineering, University of Arizona, Tucson, Arizona 85724
- Department of Medicine, Sarver Heart Center, University of Arizona, Tucson, Arizona 85724 43Artificial Heart Department, Banner University Medical Center, University of Arizona, Tucson, Arizona 85724
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Zhang X, Kampourakis T, Yan Z, Sevrieva I, Irving M, Sun YB. Distinct contributions of the thin and thick filaments to length-dependent activation in heart muscle. eLife 2017; 6. [PMID: 28229860 PMCID: PMC5365314 DOI: 10.7554/elife.24081] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Accepted: 02/20/2017] [Indexed: 12/02/2022] Open
Abstract
The Frank-Starling relation is a fundamental auto-regulatory property of the heart that ensures the volume of blood ejected in each heartbeat is matched to the extent of venous filling. At the cellular level, heart muscle cells generate higher force when stretched, but despite intense efforts the underlying molecular mechanism remains unknown. We applied a fluorescence-based method, which reports structural changes separately in the thick and thin filaments of rat cardiac muscle, to elucidate that mechanism. The distinct structural changes of troponin C in the thin filaments and myosin regulatory light chain in the thick filaments allowed us to identify two aspects of the Frank-Starling relation. Our results show that the enhanced force observed when heart muscle cells are maximally activated by calcium is due to a change in thick filament structure, but the increase in calcium sensitivity at lower calcium levels is due to a change in thin filament structure. DOI:http://dx.doi.org/10.7554/eLife.24081.001 The heart needs to pump out the same volume of blood that enters it. This is not as simple as it sounds, as changes in heart rate – for example, in response to exercise – alter how hard the heart must pump. When blood flows into the heart it stretches the heart muscle, which consists of units called sarcomeres. Sarcomeres contain two types of protein filament, known as thick filaments and thin filaments. When a heartbeat is triggered by calcium ions flowing into the heart muscle cells, the thick filaments slide over the thin filaments. This causes the heart muscle cell to contract. The Frank–Starling mechanism helps to regulate the contraction of the heart. This mechanism has two aspects. Firstly, as the sarcomere lengthens, its protein filaments are able to contract with more force for a given high level of calcium ions. Secondly, the lengthening of the sarcomere makes the filaments more sensitive to calcium ions, which again causes the heart to contract more forcefully. However, the molecular mechanisms that underlie these effects were not clear. Zhang et al. have now studied rat heart muscle cells using a new fluorescence-based method that can detect structural changes in the thick and thin filaments. The results show that the increased force that is generated when sarcomeres are stretched can be accounted for by changes in the structure of the thick filament. In contrast, the increase in calcium sensitivity that occurs as the sarcomere lengthens is largely due to structural alterations in the thin filament. These two processes can be controlled independently, but work together in the Frank–Starling mechanism. Now that we better understand the molecular basis of the Frank–Starling mechanism, further work could investigate new strategies for designing and testing treatments for heart disease. DOI:http://dx.doi.org/10.7554/eLife.24081.002
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Affiliation(s)
- Xuemeng Zhang
- Randall Division of Cell and Molecular Biophysics, King's College London, London, United Kingdom.,British Heart Foundation Centre of Research Excellence, King's College London, London, United Kingdom
| | - Thomas Kampourakis
- Randall Division of Cell and Molecular Biophysics, King's College London, London, United Kingdom.,British Heart Foundation Centre of Research Excellence, King's College London, London, United Kingdom
| | - Ziqian Yan
- Randall Division of Cell and Molecular Biophysics, King's College London, London, United Kingdom.,British Heart Foundation Centre of Research Excellence, King's College London, London, United Kingdom
| | - Ivanka Sevrieva
- Randall Division of Cell and Molecular Biophysics, King's College London, London, United Kingdom.,British Heart Foundation Centre of Research Excellence, King's College London, London, United Kingdom
| | - Malcolm Irving
- Randall Division of Cell and Molecular Biophysics, King's College London, London, United Kingdom.,British Heart Foundation Centre of Research Excellence, King's College London, London, United Kingdom
| | - Yin-Biao Sun
- Randall Division of Cell and Molecular Biophysics, King's College London, London, United Kingdom.,British Heart Foundation Centre of Research Excellence, King's College London, London, United Kingdom
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Ichige MHA, Pereira MG, Brum PC, Michelini LC. Experimental Evidences Supporting the Benefits of Exercise Training in Heart Failure. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 999:181-206. [PMID: 29022264 DOI: 10.1007/978-981-10-4307-9_11] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Heart Failure (HF), a common end point for many cardiovascular diseases, is a syndrome with a very poor prognosis. Although clinical trials in HF have achieved important outcomes in reducing mortality, little is known about functional mechanisms conditioning health improvement in HF patients. In parallel with clinical studies, basic science has been providing important discoveries to understand the mechanisms underlying the pathophysiology of HF, as well as to identify potential targets for the treatment of this syndrome. In spite of being the end-point of cardiovascular derangements caused by different etiologies, autonomic dysfunction, sympathetic hyperactivity, oxidative stress, inflammation and hormonal activation are common factors involved in the progression of this syndrome. Together these causal factors create a closed link between three important organs: brain, heart and the skeletal muscle. In the past few years, we and other groups have studied the beneficial effects of aerobic exercise training as a safe therapy to avoid the progression of HF. As summarized in this chapter, exercise training, a non-pharmacological tool without side effects, corrects most of the HF-induced neurohormonal and local dysfunctions within the brain, heart and skeletal muscles. These adaptive responses reverse oxidative stress, reduce inflammation, ameliorate neurohormonal control and improve both cardiovascular and skeletal muscle function, thus increasing the quality of life and reducing patients' morbimortality.
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Affiliation(s)
- Marcelo H A Ichige
- Department of Physiology & Biophysics, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, Brazil
| | - Marcelo G Pereira
- Department of Biodynamics of Human Body Movement, School of Physical Education and Sport, University of Sao Paulo, Sao Paulo, Brazil
| | - Patrícia C Brum
- Department of Biodynamics of Human Body Movement, School of Physical Education and Sport, University of Sao Paulo, Sao Paulo, Brazil. .,National Institute for Science & Technology - INCT (In)activity & Exercise, CNPq - Niterói (RJ), Rio de Janeiro, Brazil.
| | - Lisete C Michelini
- Department of Physiology & Biophysics, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, Brazil.,National Institute for Science & Technology - INCT (In)activity & Exercise, CNPq - Niterói (RJ), Rio de Janeiro, Brazil
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Shimozawa T, Hirokawa E, Kobirumaki-Shimozawa F, Oyama K, Shintani SA, Terui T, Kushida Y, Tsukamoto S, Fujii T, Ishiwata S, Fukuda N. In vivo cardiac nano-imaging: A new technology for high-precision analyses of sarcomere dynamics in the heart. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2016; 124:31-40. [PMID: 27664770 DOI: 10.1016/j.pbiomolbio.2016.09.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Revised: 09/15/2016] [Accepted: 09/20/2016] [Indexed: 12/01/2022]
Abstract
The cardiac pump function is a result of a rise in intracellular Ca2+ and the ensuing sarcomeric contractions [i.e., excitation-contraction (EC) coupling] in myocytes in various locations of the heart. In order to elucidate the heart's mechanical properties under various settings, cardiac imaging is widely performed in today's clinical as well as experimental cardiology by using echocardiogram, magnetic resonance imaging and computed tomography. However, because these common techniques detect local myocardial movements at a spatial resolution of ∼100 μm, our knowledge on the sub-cellular mechanisms of the physiology and pathophysiology of the heart in vivo is limited. This is because (1) EC coupling occurs in the μm partition in a myocyte and (2) cardiac sarcomeres generate active force upon a length change of ∼100 nm on a beat-to-beat basis. Recent advances in optical technologies have enabled measurements of intracellular Ca2+ dynamics and sarcomere length displacements at high spatial and temporal resolution in the beating heart of living rodents. Future studies with these technologies are warranted to open a new era in cardiac research.
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Affiliation(s)
- Togo Shimozawa
- Department of Life Science and Medical Bioscience, School of Advanced Science and Engineering, Waseda University, 2-2 Wakamatsu-cho, Sinjuku-ku, Tokyo 162-8480, Japan
| | - Erisa Hirokawa
- Department of Cell Physiology, The Jikei University School of Medicine, 3-25-8 Nishi-shinbashi, Minato-ku, Tokyo 105-8461, Japan
| | - Fuyu Kobirumaki-Shimozawa
- Department of Cell Physiology, The Jikei University School of Medicine, 3-25-8 Nishi-shinbashi, Minato-ku, Tokyo 105-8461, Japan
| | - Kotaro Oyama
- Department of Cell Physiology, The Jikei University School of Medicine, 3-25-8 Nishi-shinbashi, Minato-ku, Tokyo 105-8461, Japan
| | - Seine A Shintani
- Department of Physics, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo Bunkyo-ku, Tokyo 113-0033, Japan
| | - Takako Terui
- Department of Anesthesiology, The Jikei University School of Medicine, 3-25-8 Nishi-shinbashi, Minato-ku, Tokyo 105-8461, Japan
| | - Yasuharu Kushida
- Department of Cell Physiology, The Jikei University School of Medicine, 3-25-8 Nishi-shinbashi, Minato-ku, Tokyo 105-8461, Japan
| | - Seiichi Tsukamoto
- Department of Cell Physiology, The Jikei University School of Medicine, 3-25-8 Nishi-shinbashi, Minato-ku, Tokyo 105-8461, Japan
| | - Teruyuki Fujii
- Department of Cell Physiology, The Jikei University School of Medicine, 3-25-8 Nishi-shinbashi, Minato-ku, Tokyo 105-8461, Japan
| | - Shin'ichi Ishiwata
- Department of Physics, Faculty of Advanced Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku-ku, Tokyo 169-8555, Japan
| | - Norio Fukuda
- Department of Cell Physiology, The Jikei University School of Medicine, 3-25-8 Nishi-shinbashi, Minato-ku, Tokyo 105-8461, Japan.
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49
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Friedberg MK, Margossian R, Lu M, Mercer-Rosa L, Henderson HT, Nutting A, Friedman K, Molina KM, Altmann K, Canter C, Sleeper LA, Colan SD. Systolic-diastolic functional coupling in healthy children and in those with dilated cardiomyopathy. J Appl Physiol (1985) 2016; 120:1301-18. [PMID: 26940654 DOI: 10.1152/japplphysiol.00635.2015] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2015] [Accepted: 03/02/2016] [Indexed: 11/22/2022] Open
Abstract
Systolic and diastolic function affect dilated cardiomyopathy (DCM) outcomes. However, systolic-diastolic coupling, as a distinct characteristic, may itself affect function but is poorly characterized. We hypothesized that echocardiographic left ventricular (LV) longitudinal systolic tissue velocities (S') correlate with diastolic longitudinal velocities (E') and that their relationship is associated with ventricular function and that this relationship is impaired in pediatric DCM. We analyzed data from the Pediatric Heart Network Ventricular Volume Variability study, using linear regression and generalized additive modeling to assess relationships between S' and E' at the lateral and septal mitral annulus. We explored relationships between the systolic:diastolic (S:D) coupling ratio (S':E' relative to age) and ventricular function. Up to 4 echocardiograms from 130 DCM patients (mean age: 9.3 ± 6.1 yr) and 1 echocardiogram from each of 591 healthy controls were analyzed. S' and E' were linearly related in controls (r = 0.64, P < 0.001) and DCM (r = 0.83, P < 0.001). In DCM, the magnitude of association between S' and E' was reduced with progressive ventricular remodeling. The S:D ratio was more strongly associated with LV function in controls vs. DCM. The septal S:D ratio was higher (presumed worse) in DCM vs. controls (0.69 ± 0.13 vs. 0.62 ± 0.12, P = 0.001). A higher septal S:D ratio was associated with worse LV dimensions (parameter estimate: 0.0061, P = 0.004), mass (parameter estimate: 0.0074, P = 0.002), ejection fraction (parameter estimate: -0.0303, P = 0.024), and inflow propagation (parameter estimate: -0.3538, P < .001). S:D coupling becomes weaker in DCM with LV remodeling and dysfunction. The S:D coupling ratio may be useful to assess coupling, warranting study in relation to patient outcomes.
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Affiliation(s)
| | | | - Minmin Lu
- New England Research Institutes, Watertown, Massachusetts
| | | | | | - Arni Nutting
- Medical University of South Carolina, Charleston, South Carolina
| | | | | | - Karen Altmann
- Columbia University Medical Center, New York, New York; and
| | - Charles Canter
- Washington University, St. Louis Children's Hospital, St. Louis, Missouri
| | - Lynn A Sleeper
- New England Research Institutes, Watertown, Massachusetts
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50
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Lookin O, Balakin A, Kuznetsov D, Protsenko Y. The length-dependent activation of contraction is equally impaired in impuberal male and female rats in monocrotaline-induced right ventricular failure. Clin Exp Pharmacol Physiol 2015; 42:1198-206. [DOI: 10.1111/1440-1681.12471] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2015] [Revised: 07/23/2015] [Accepted: 07/27/2015] [Indexed: 11/29/2022]
Affiliation(s)
- Oleg Lookin
- Laboratory of Biological Motility; Institute of Immunology and Physiology; Ural Branch of Russian Academy of Sciences; Yekaterinburg Russian Federation
| | - Alexander Balakin
- Laboratory of Biological Motility; Institute of Immunology and Physiology; Ural Branch of Russian Academy of Sciences; Yekaterinburg Russian Federation
| | - Daniil Kuznetsov
- Laboratory of Biological Motility; Institute of Immunology and Physiology; Ural Branch of Russian Academy of Sciences; Yekaterinburg Russian Federation
| | - Yuri Protsenko
- Laboratory of Biological Motility; Institute of Immunology and Physiology; Ural Branch of Russian Academy of Sciences; Yekaterinburg Russian Federation
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