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Contrasting Effects of Inhibition of Phosphodiesterase 3 and 5 on Cardiac Function and Interstitial Fibrosis in Rats With Isoproterenol-Induced Cardiac Dysfunction. J Cardiovasc Pharmacol 2020; 73:195-205. [PMID: 30839513 DOI: 10.1097/fjc.0000000000000652] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Myocardial relaxation and stiffness are influenced by fibrillar collagen content. Cyclic nucleotide signaling regulators have been investigated targeting more effective modulation of collagen deposition during myocardial healing process. To assess the effects of phosphodiesterase type 3 and phosphodiesterase type 5 inhibitors on cardiac function and left ventricular myocardial fibrosis in catecholamine-induced myocardial injury, sildenafil and pimobendan were administered to male Wistar rats 24 hours after isoproterenol injection. Echocardiography and electrocardiogram were performed to assess kinetic and rhythm changes during 45 days of drug administration. At the end of study, type I and type III collagen were measured through immunohistochemistry analysis, and left ventricular pressure was assessed through invasive method. Echocardiography assessment showed increased relative wall thickness at 45 days in pimobendan group with significant diastolic dysfunction and increased collagen I deposition compared with nontreated positive group (3.03 ± 0.31 vs. 2.73 ± 0.28%, P < 0.05). Diastolic pressure correlated positively with type I collagen (r = 0.54, P < 0.05). Type III collagen analysis did not demonstrate difference among the groups. Sildenafil administration attenuated type I collagen deposition (2.15 ± 0.51 vs. positive group, P < 0.05) and suggested to be related to arrhythmic events. Arrhythmic events were not related to the quantity of fibrillar collagen deposition. Although negative modulation of collagen synthesis through cyclic nucleotides signaling have shown promising results, in this study, pimobendan postconditioning resulted in increased collagen type I formation and severe diastolic dysfunction while sildenafil postconditioning reduced collagen type I deposition and attenuated diastolic dysfunction.
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How myofilament strain and strain rate lead the dance of the cardiac cycle. Arch Biochem Biophys 2019; 664:62-67. [PMID: 30710504 PMCID: PMC6589344 DOI: 10.1016/j.abb.2019.01.034] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 01/21/2019] [Accepted: 01/28/2019] [Indexed: 12/20/2022]
Abstract
Movement of the myocardium can modify organ-level cardiac function and its molecular (crossbridge) mechanisms. This motion, which is defined by myocardial strain and strain rate (muscle shortening, lengthening, and the speed of these movements), occurs throughout the cardiac cycle, including during isovolumic periods. This review highlights how the left ventricular myocardium moves throughout the cardiac cycle, how muscle mechanics experiments provide insight into the regulation of forces used to move blood in and out of the left ventricle, and its impact on (and regulation by) crossbridge and sarcomere kinetics. We specifically highlight how muscle mechanics experiments explain how myocardial relaxation is accelerated by lengthening (strain rate) during late systole and isovolumic relaxation, a lengthening which has been measured in human hearts. Advancing and refining both in vivo measurement and ex vivo protocols with physiologic strain and strain rates could reveal important insights into molecular (crossbridge) kinetics. These advances could provide an improvement in both diagnosis and precise treatment of cardiac dysfunction.
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Pyridoxamine improves survival and limits cardiac dysfunction after MI. Sci Rep 2017; 7:16010. [PMID: 29167580 PMCID: PMC5700185 DOI: 10.1038/s41598-017-16255-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Accepted: 11/09/2017] [Indexed: 01/13/2023] Open
Abstract
Advanced glycation end products (AGEs) play a key role in the progression of heart failure. Whether treatments limiting AGEs formation would prevent adverse left ventricular remodeling after myocardial infarction (MI) remain unknown. We investigated whether pyridoxamine (PM) could limit adverse cardiac outcome in MI. Rats were divided into MI, MI + PM and Sham. Echocardiography and hemodynamic parameters were used to assess cardiac function 8 weeks post-surgery. Total interstitial collagen, collagen I and collagen III were quantified using Sirius Red and polarized light microscopy. PM improved survival following LAD occlusion. Pre-treatment with PM significantly decreased the plasma AGEs levels. MI rats treated with PM displayed reduced left ventricular end-diastolic pressure and tau compared to untreated MI rats. Deformation parameters were also improved with PM. The preserved diastolic function was related to the reduced collagen content, in particular in the highly cross-linked collagen type I, mainly in the peri-infarct region, although not via TGF-β1 pathway. Our data indicate that PM treatment prevents the increase in AGEs levels and reduces collagen levels in a rat model of MI, resulting in an improved cardiac phenotype. As such, therapies targeting formation of AGEs might be beneficial in the prevention and/or treatment of maladaptive remodeling following MI.
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Hong SJ, Shim CY, Kim D, Cho IJ, Hong GR, Moon SH, Lee HJ, Lee JK, Choi D, Jang Y, Ha JW. Dynamic change in left ventricular apical back rotation: a marker of diastolic suction with exercise. Eur Heart J Cardiovasc Imaging 2017; 19:12-19. [DOI: 10.1093/ehjci/jex241] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Accepted: 10/13/2017] [Indexed: 11/13/2022] Open
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Chung CS, Shmuylovich L, Kovács SJ. What global diastolic function is, what it is not, and how to measure it. Am J Physiol Heart Circ Physiol 2015; 309:H1392-406. [DOI: 10.1152/ajpheart.00436.2015] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Accepted: 08/17/2015] [Indexed: 12/17/2022]
Abstract
Despite Leonardo da Vinci's observation (circa 1511) that “the atria or filling chambers contract together while the pumping chambers or ventricles are relaxing and vice versa,” the dynamics of four-chamber heart function, and of diastolic function (DF) in particular, are not generally appreciated. We view DF from a global perspective, while characterizing it in terms of causality and clinical relevance. Our models derive from the insight that global DF is ultimately a result of forces generated by elastic recoil, modulated by cross-bridge relaxation, and load. The interaction between recoil and relaxation results in physical wall motion that generates pressure gradients that drive fluid flow, while epicardial wall motion is constrained by the pericardial sac. Traditional DF indexes (τ, E/E′, etc.) are not derived from causal mechanisms and are interpreted as approximating either stiffness or relaxation, but not both, thereby limiting the accuracy of DF quantification. Our derived kinematic models of isovolumic relaxation and suction-initiated filling are extensively validated, quantify the balance between stiffness and relaxation, and provide novel mechanistic physiological insight. For example, causality-based modeling provides load-independent indexes of DF and reveals that both stiffness and relaxation modify traditional DF indexes. The method has revealed that the in vivo left ventricular equilibrium volume occurs at diastasis, predicted novel relationships between filling and wall motion, and quantified causal relationships between ventricular and atrial function. In summary, by using governing physiological principles as a guide, we define what global DF is, what it is not, and how to measure it.
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Affiliation(s)
- Charles S. Chung
- Department of Physiology and Center for Muscle Biology, University of Kentucky, Lexington, Kentucky, and Department of Physiology, Wayne State University, Detroit, Michigan; and
| | - Leonid Shmuylovich
- Cardiovascular Biophysics Laboratory, Cardiovascular Division, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri
| | - Sándor J. Kovács
- Cardiovascular Biophysics Laboratory, Cardiovascular Division, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri
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Inoue K, Asanuma T, Masuda K, Sakurai D, Higaki J, Nakatani S. Compensatory increase of left atrial external work to left ventricular dysfunction caused by afterload increase. Am J Physiol Heart Circ Physiol 2015; 308:H904-12. [DOI: 10.1152/ajpheart.00530.2014] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/30/2014] [Accepted: 01/29/2015] [Indexed: 11/22/2022]
Abstract
Afterload mismatch can cause acute decompensation leading to an occurrence of acute heart failure. We investigated how the left atrium (LA) and left ventricle (LV) react to acute increases in afterload using speckle tracking echocardiography (STE). LA strain and volume were obtained by STE in 10 dogs during banding of descending aorta (AoB). Simultaneously, LA pressure was measured by a micromanometer-tipped catheter. LA peak negative strain during LA contraction, strain change during LA relaxation (early reservoir strain), and that during LA dilatation (late reservoir strain) were obtained from LA longitudinal strain-volume curves. From pressure-strain curves, the areas of A-loop and V-loops were computed as the work during active contraction and relaxation (A-work) and that during passive filling and emptying (V-work). AoB increased LV systolic pressure (105 ± 15 vs. 163 ± 12 mmHg, P < 0.01) and mean LA pressure (3.8 ± 1.2 vs. 7.1 ± 2.0 mmHg, P < 0.01). LV global circumferential strain decreased (−18.8 ± 3.5 vs. −13.2 ± 3.5%, P < 0.01), but LV stroke volume was maintained (8.4 ± 2.3 vs. 9.6 ± 3.6 ml). LA peak negative strain (−2.9 ± 2.3 vs. −9.8 ± 4.0%, P < 0.01) and early reservoir strain (4.5 ± 2.1 vs. 7.7 ± 2.4%, P < 0.05) increased by AoB, but late reservoir strain did not change (8.9 ± 3.4 vs. 6.1 ± 3.4%). A-work significantly increased (3.2 ± 2.0 vs. 19.2 ± 15.1 mmHg %, P < 0.01), whereas V-work did not change (13.3 ± 7.1 vs. 13.1 ± 7.7 mmHg %). In conclusion, LA external work during active contraction and relaxation increased as compensation for LV dysfunction during aortic banding. Atrial dysfunction may lead failure of this mechanism and hemodynamic decompensation.
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Affiliation(s)
- Katsuji Inoue
- Department of Cardiology, Pulmonology, Hypertension and Nephrology, Ehime University Graduate School of Medicine, Toon, Ehime, Japan; and
| | - Toshihiko Asanuma
- Division of Functional Diagnostics, Department of Health Sciences, Osaka University Graduate School of Medicine, Suita, Osaka, Japan
| | - Kasumi Masuda
- Division of Functional Diagnostics, Department of Health Sciences, Osaka University Graduate School of Medicine, Suita, Osaka, Japan
| | - Daisuke Sakurai
- Division of Functional Diagnostics, Department of Health Sciences, Osaka University Graduate School of Medicine, Suita, Osaka, Japan
| | - Jitsuo Higaki
- Department of Cardiology, Pulmonology, Hypertension and Nephrology, Ehime University Graduate School of Medicine, Toon, Ehime, Japan; and
| | - Satoshi Nakatani
- Division of Functional Diagnostics, Department of Health Sciences, Osaka University Graduate School of Medicine, Suita, Osaka, Japan
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Arutunyan AH. Atrioventricular plane displacement is the sole mechanism of atrial and ventricular refill. Am J Physiol Heart Circ Physiol 2015; 308:H1317-20. [PMID: 25795710 DOI: 10.1152/ajpheart.00058.2015] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/23/2015] [Accepted: 03/19/2015] [Indexed: 11/22/2022]
Affiliation(s)
- Ara H Arutunyan
- Department of Pharmacology and Physiology, George Washington University, Washington, District of Columbia
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Saito M, Kaye G, Negishi K, Linker N, Gammage M, Kosmala W, Marwick TH. Dyssynchrony, contraction efficiency and regional function with apical and non-apical RV pacing. Heart 2015; 101:600-8. [DOI: 10.1136/heartjnl-2014-306990] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
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