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Zhang D, Li B, Li B, Tang Y. Regulation of left atrial fibrosis induced by mitral regurgitation by SIRT1. Sci Rep 2020; 10:7278. [PMID: 32350389 PMCID: PMC7190846 DOI: 10.1038/s41598-020-64308-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Accepted: 04/10/2020] [Indexed: 11/09/2022] Open
Abstract
SIRT1 (silent information regulator 1) is a histone deacetylase. It can sense the energy level in cells and delay cell senescence, leading to resistance to external stress and improving metabolism. Mitral regurgitation (MR) is a common disease in cardiac surgery. However, there are no previous studies on SIRT1 and left atrial fibrosis caused by MR. In this study, we aimed to explore the regulatory effect of SIRT1 on left atrial fibrosis induced by MR. We used Guizhou miniature pigs to establish an MR model and a sham operation model after anaesthesia induction and respiratory intubation, and these model animals were followed for 30 months after the surgery. The differential distribution and expression of SIRT1 and collagen I in the left atrium was determined by immunofluorescence and Western blotting. Furthermore, we treated NIH3T3 fibroblasts (CFs) with resveratrol and Angiotensin II (Ang II) to analyse the specific mechanism involved in the development of myocardial fibrosis. The results showed that the MR model was successfully constructed. There were 8 pigs in the MR group and 6 pigs in the control group. In both the animal experiments and the cell experiments, the expression of collagen I in the MR group was increased significantly compared to that in the control group, while the expression of SIRT1 was decreased.
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Affiliation(s)
- Dong Zhang
- Beijing Jishuitan Hospital, Department of Thoracic Surgery, Beijing, China
| | - Bo Li
- The Seventh Affiliated Hospital, Sun Yat-sen University, Department of Cardiac Surgery, Shenzhen, China
| | - Bin Li
- Animal Experimental Centre, Beijing Key Laboratory of Preclinical Research and Evaluation for Cardiovascular Implant Materials, State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Centre for Cardiovascular Disease, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Yue Tang
- Animal Experimental Centre, Beijing Key Laboratory of Preclinical Research and Evaluation for Cardiovascular Implant Materials, State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Centre for Cardiovascular Disease, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.
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2
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Abstract
Hypertension is the most common cardiovascular risk factor and underlies heart failure, coronary artery disease, stroke, and chronic kidney disease. Hypertensive heart disease can manifest as cardiac arrhythmias. Supraventricular and ventricular arrhythmias may occur in the hypertensive patients. Atrial fibrillation and hypertension contribute to an increased risk of stroke. Some antihypertensive drugs predispose to electrolyte abnormalities, which may result in atrial and ventricular arrhythmias. A multipronged strategy involving appropriate screening, aggressive lifestyle modifications, and optimal pharmacotherapy can result in improved blood pressure control and prevent the onset or delay progression of heart failure, coronary artery disease, and cardiac arrhythmias.
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Affiliation(s)
- Muhammad R Afzal
- Division of Cardiovascular Medicine, The Ohio State University Wexner Medical Center, 473 West 12th Avenue, Suite 200, Columbus, OH 43210, USA
| | - Salvatore Savona
- Division of Cardiovascular Medicine, The Ohio State University Wexner Medical Center, 473 West 12th Avenue, Suite 200, Columbus, OH 43210, USA
| | - Omar Mohamed
- Division of Cardiovascular Medicine, The Ohio State University Wexner Medical Center, 473 West 12th Avenue, Suite 200, Columbus, OH 43210, USA
| | - Aayah Mohamed-Osman
- Division of Cardiovascular Medicine, The Ohio State University Wexner Medical Center, 473 West 12th Avenue, Suite 200, Columbus, OH 43210, USA
| | - Steven J Kalbfleisch
- Division of Cardiovascular Medicine, The Ohio State University Wexner Medical Center, 473 West 12th Avenue, Suite 200, Columbus, OH 43210, USA.
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Li S, Jiang Z, Wen L, Feng G, Zhong G. MicroRNA-208a-3p contributes to connexin40 remolding in human chronic atrial fibrillation. Exp Ther Med 2017; 14:5355-5362. [PMID: 29285063 PMCID: PMC5740716 DOI: 10.3892/etm.2017.5225] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Accepted: 07/27/2017] [Indexed: 12/13/2022] Open
Abstract
Previous studies have demonstrated that connexin40 (Cx40) remolding is involved in atrial fibrillation (AF). GJA5 encoding Cx40 is a potential target mRNA of microRNA-208a-3p (miR-208a-3p), as indicated by preliminary bioinformatics analyses. However, the exact effect of miR-208a-3p on Cx40 in human chronic AF has remained elusive. The present study demonstrated the role of miR-208a-3p in human chronic AF and further investigated the effect of miR-208a-3p on Cx40 expression. A total of 19 patients with AF and 18 patients with sinus rhythm (SR) were enrolled. The AC16 cell line was treated with miR-208a-3p inhibitor or mimics. The miR-208a-3p in right atrial appendage (RAA) tissues of patients was measured by in situ hybridization and reverse-transcription quantitative polymerase chain reaction (RT-qPCR). Furthermore, the expression of Cx40 in the RAA of patients and in AC16 cells treated with miR-208a-3p inhibitor or mimics were detected by RT-qPCR and western blot analysis. A luciferase assay was performed to confirm whether Cx40 was directly targeted by miR-208a-3p. The miR-208a-3p levels in patients with AF were significantly increased compared with those in patients with SR. Conversely, the Cx40 protein levels were significantly decreased and lateralization of Cx40 was observed in patients with AF. miR-208a-3p inhibitor led to a significant upregulation of the protein expression of Cx40 in AC16 cells, while miR-208a-3p mimics led to a significant downregulation. However, the luciferase assay demonstrated that GJA5 was not a direct target gene of miR-208a-3p. The findings still suggested that miR-208a-3p may be involved in human chronic AF by mediating atrial Cx40 remolding, and may represent a potential therapeutic target for AF.
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Affiliation(s)
- Shanshan Li
- Department of Cardiology, The First Affiliated Hospital, Guangxi Medical University, Nanning, Guangxi 530021, P.R. China
| | - Zhiyuan Jiang
- Department of Cardiology, The First Affiliated Hospital, Guangxi Medical University, Nanning, Guangxi 530021, P.R. China.,Hypertension Division, The First Affiliated Hospital, Guangxi Medical University, Nanning, Guangxi 530021, P.R. China
| | - Lina Wen
- Department of Cardiology, The First Affiliated Hospital, Guangxi Medical University, Nanning, Guangxi 530021, P.R. China
| | - Guirong Feng
- Department of Cardiology, The First Affiliated Hospital, Guangxi Medical University, Nanning, Guangxi 530021, P.R. China
| | - Guoqiang Zhong
- Department of Cardiology, The First Affiliated Hospital, Guangxi Medical University, Nanning, Guangxi 530021, P.R. China
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Abstract
Myocardial injury, mechanical stress, neurohormonal activation, inflammation, and/or aging all lead to cardiac remodeling, which is responsible for cardiac dysfunction and arrhythmogenesis. Of the key histological components of cardiac remodeling, fibrosis either in the form of interstitial, patchy, or dense scars, constitutes a key histological substrate of arrhythmias. Here we discuss current research findings focusing on the role of fibrosis, in arrhythmogenesis. Numerous studies have convincingly shown that patchy or interstitial fibrosis interferes with myocardial electrophysiology by slowing down action potential propagation, initiating reentry, promoting after-depolarizations, and increasing ectopic automaticity. Meanwhile, there has been increasing appreciation of direct involvement of myofibroblasts, the activated form of fibroblasts, in arrhythmogenesis. Myofibroblasts undergo phenotypic changes with expression of gap-junctions and ion channels thereby forming direct electrical coupling with cardiomyocytes, which potentially results in profound disturbances of electrophysiology. There is strong evidence that systemic and regional inflammatory processes contribute to fibrogenesis (i.e., structural remodeling) and dysfunction of ion channels and Ca2+ homeostasis (i.e., electrical remodeling). Recognizing the pivotal role of fibrosis in the arrhythmogenesis has promoted clinical research on characterizing fibrosis by means of cardiac imaging or fibrosis biomarkers for clinical stratification of patients at higher risk of lethal arrhythmia, as well as preclinical research on the development of antifibrotic therapies. At the end of this review, we discuss remaining key questions in this area and propose new research approaches. © 2017 American Physiological Society. Compr Physiol 7:1009-1049, 2017.
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Affiliation(s)
- My-Nhan Nguyen
- Baker Heart and Diabetes Institute, Melbourne, Australia.,Central Clinical School, Monash University, Melbourne, Australia
| | - Helen Kiriazis
- Baker Heart and Diabetes Institute, Melbourne, Australia
| | - Xiao-Ming Gao
- Baker Heart and Diabetes Institute, Melbourne, Australia.,Central Clinical School, Monash University, Melbourne, Australia
| | - Xiao-Jun Du
- Baker Heart and Diabetes Institute, Melbourne, Australia.,Central Clinical School, Monash University, Melbourne, Australia
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Arrhythmia and thyroid dysfunction. Herz 2014; 40 Suppl 2:101-9. [DOI: 10.1007/s00059-014-4123-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2014] [Revised: 05/20/2014] [Accepted: 05/27/2014] [Indexed: 10/25/2022]
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Andrade J, Khairy P, Dobrev D, Nattel S. The clinical profile and pathophysiology of atrial fibrillation: relationships among clinical features, epidemiology, and mechanisms. Circ Res 2014; 114:1453-68. [PMID: 24763464 DOI: 10.1161/circresaha.114.303211] [Citation(s) in RCA: 804] [Impact Index Per Article: 80.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Atrial fibrillation (AF) is the most common arrhythmia (estimated lifetime risk, 22%-26%). The aim of this article is to review the clinical epidemiological features of AF and to relate them to underlying mechanisms. Long-established risk factors for AF include aging, male sex, hypertension, valve disease, left ventricular dysfunction, obesity, and alcohol consumption. Emerging risk factors include prehypertension, increased pulse pressure, obstructive sleep apnea, high-level physical training, diastolic dysfunction, predisposing gene variants, hypertrophic cardiomyopathy, and congenital heart disease. Potential risk factors are coronary artery disease, kidney disease, systemic inflammation, pericardial fat, and tobacco use. AF has substantial population health consequences, including impaired quality of life, increased hospitalization rates, stroke occurrence, and increased medical costs. The pathophysiology of AF centers around 4 general types of disturbances that promote ectopic firing and reentrant mechanisms, and include the following: (1) ion channel dysfunction, (2) Ca(2+)-handling abnormalities, (3) structural remodeling, and (4) autonomic neural dysregulation. Aging, hypertension, valve disease, heart failure, myocardial infarction, obesity, smoking, diabetes mellitus, thyroid dysfunction, and endurance exercise training all cause structural remodeling. Heart failure and prior atrial infarction also cause Ca(2+)-handling abnormalities that lead to focal ectopic firing via delayed afterdepolarizations/triggered activity. Neural dysregulation is central to atrial arrhythmogenesis associated with endurance exercise training and occlusive coronary artery disease. Monogenic causes of AF typically promote the arrhythmia via ion channel dysfunction, but the mechanisms of the more common polygenic risk factors are still poorly understood and under intense investigation. Better recognition of the clinical epidemiology of AF, as well as an improved appreciation of the underlying mechanisms, is needed to develop improved methods for AF prevention and management.
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Affiliation(s)
- Jason Andrade
- From Department of Medicine and Research Center, Montreal Heart Institute and Université de Montréal, Montreal, Quebec, Canada (J.A., P.K., S.N.); Department of Medicine, University of British Columbia, Vancouver, British Columbia, Canada (J.A.); and Faculty of Medicine, Institute of Pharmacology, University Duisburg-Essen, Essen, Germany (D.D.)
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Freitas F, Estato V, Carvalho VF, Torres RC, Lessa MA, Tibiriçá E. Cardiac microvascular rarefaction in hyperthyroidism-induced left ventricle dysfunction. Microcirculation 2014; 20:590-8. [PMID: 23510303 DOI: 10.1111/micc.12057] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2012] [Accepted: 03/15/2013] [Indexed: 11/27/2022]
Abstract
OBJECTIVE The pathophysiology underlying hyperthyroidism-induced left ventricle (LV) dysfunction and hypertrophy directly involves the heart and indirectly involves the neuroendocrine systems. The effects of hyperthyroidism on the microcirculation are still controversial in experimental models. We investigated the effects of hyperthyroidism on the cardiac function and microcirculation of an experimental rat model. METHODS Male Wistar rats (170-250 g) were divided into two groups: the euthyroid group (n = 10), which was treated with 0.9% saline solution, and the hyperthyroid group (n = 10), which was treated with l-thyroxine (600 μg/kg/day, i.p.) during 14 days. An echocardiographic study was performed to evaluate the alterations in cardiac function, structure and geometry. The structural capillary density and the expression of angiotensin II AT1 receptor in the LV were analyzed using histochemistry and immunohistochemistry, respectively. RESULTS Hyperthyroidism was found to induce profound cardiovascular alterations, such as systolic hypertension, tachycardia, LV dysfunction, cardiac hypertrophy, and myocardial fibrosis. This study demonstrates the existence of structural capillary rarefaction and the down-regulation of the cardiac angiotensin II AT1 receptor in the myocardium of hyperthyroid rats in comparison with euthyroid rats. CONCLUSIONS Microvascular rarefaction may be involved in the pathophysiology of hyperthyroidism-induced cardiovascular alterations.
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Affiliation(s)
- Felipe Freitas
- Laboratory of Cardiovascular Investigation, Oswaldo Cruz Institute, FIOCRUZ, Rio de Janeiro, Brazil
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Silveira ALBD, de Souza Miranda MF, Mecawi AS, Melo RL, Marassi MP, Matos da Silva AC, Antunes-Rodrigues J, Olivares EL. Sexual dimorphism in autonomic changes and in the renin-angiotensin system in the hearts of mice subjected to thyroid hormone-induced cardiac hypertrophy. Exp Physiol 2014; 99:868-80. [PMID: 24659612 DOI: 10.1113/expphysiol.2013.076976] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Based on the relevance of the renin-angiotensin system and the ongoing controversy regarding the role of the sympathetic nervous system in thyroid hormone-induced cardiac hypertrophy, the aim of the present study was to establish whether the putative difference in the degree of cardiac hypertrophy exhibited by males and females might be related to differences in the sympathetic-vagal balance and/or in the cardiac renin-angiotensin system in mice of different genders. Male and female mice (n = 117) were given 0.1 mg kg(-1) of triiodothyronine or normal saline each day for 10 days consecutively. At the end of that period, study of the heart rate variability, spectral analysis and histopathological examination were performed to assess the sympathetic-vagal balance and the diameter of cardiomyocytes. The cardiac levels of angiotensin I and II were also measured. Treatment with triiodothyronine induced a greater degree of cardiac hypertrophy in male (~73%) than in female mice (~42%). This difference was attributed to greater modulation of the sympathetic nervous system and higher levels of angiotensin I and II in male than in female mice. Our data indicate that thyroid hormone-induced cardiac hypertrophy was more intense in male mice due to the synergic effect of the sympathetic nervous system and the cardiac renin-angiotensin system.
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Affiliation(s)
- Anderson Luiz Bezerra da Silveira
- Multicenter Graduate Program in Physiological Sciences, Department of Physiological Sciences, Institute of Biology, Federal Rural University of Rio de Janeiro, Seropedica, Brazil
| | - Manuela França de Souza Miranda
- Graduate Program in Veterinary Medicine, Department of Physiological Sciences, Institute of Biology, Federal Rural University of Rio de Janeiro, Seropedica, Brazil
| | - André Souza Mecawi
- Department of Physiology, School of Medicine, Ribeirao Preto USP - São Paulo, Brazil
| | - Roberto Laureano Melo
- Multicenter Graduate Program in Physiological Sciences, Department of Physiological Sciences, Institute of Biology, Federal Rural University of Rio de Janeiro, Seropedica, Brazil
| | - Michelle Porto Marassi
- Multicenter Graduate Program in Physiological Sciences, Department of Physiological Sciences, Institute of Biology, Federal Rural University of Rio de Janeiro, Seropedica, Brazil
| | - Alba Cenélia Matos da Silva
- Multicenter Graduate Program in Physiological Sciences, Department of Physiological Sciences, Institute of Biology, Federal Rural University of Rio de Janeiro, Seropedica, Brazil
| | | | - Emerson Lopes Olivares
- Multicenter Graduate Program in Physiological Sciences, Department of Physiological Sciences, Institute of Biology, Federal Rural University of Rio de Janeiro, Seropedica, Brazil Graduate Program in Veterinary Medicine, Department of Physiological Sciences, Institute of Biology, Federal Rural University of Rio de Janeiro, Seropedica, Brazil
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