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Corporan D, Onohara D, Amedi A, Saadeh M, Guyton RA, Kumar S, Padala M. Hemodynamic and transcriptomic studies suggest early left ventricular dysfunction in a preclinical model of severe mitral regurgitation. J Thorac Cardiovasc Surg 2021; 161:961-976.e22. [PMID: 33277035 PMCID: PMC7889661 DOI: 10.1016/j.jtcvs.2020.08.119] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/26/2020] [Revised: 08/06/2020] [Accepted: 08/24/2020] [Indexed: 02/07/2023]
Abstract
OBJECTIVE Primary mitral regurgitation is a valvular lesion in which the left ventricular ejection fraction remains preserved for long periods, delaying a clinical trigger for mitral valve intervention. In this study, we sought to investigate whether adverse left ventricular remodeling occurs before a significant fall in ejection fraction and characterize these changes. METHODS Sixty-five rats were induced with severe mitral regurgitation by puncturing the mitral valve leaflet with a 23-G needle using ultrasound guidance. Rats underwent longitudinal cardiac echocardiography at biweekly intervals and hearts explanted at 2 weeks (n = 15), 10 weeks (n = 15), 20 weeks (n = 15), and 40 weeks (n = 15). Sixty age- and weight-matched healthy rats were used as controls. Unbiased RNA-sequencing was performed at each terminal point. RESULTS Regurgitant fraction was 40.99 ± 9.40%, with pulmonary flow reversal in the experimental group, and none in the control group. Significant fall in ejection fraction occurred at 14 weeks after mitral regurgitation induction. However, before 14 weeks, end-diastolic volume increased by 93.69 ± 52.38% (P < .0001 compared with baseline), end-systolic volume increased by 118.33 ± 47.54% (P < .0001 compared with baseline), and several load-independent pump function indices were reduced. Transcriptomic data at 2 and 10 weeks before fall in ejection fraction indicated up-regulation of myocyte remodeling and oxidative stress pathways, whereas those at 20 and 40 weeks indicated extracellular matrix remodeling. CONCLUSIONS In this rodent model of mitral regurgitation, left ventricular ejection fraction was preserved for a long duration, yet rapid and severe left ventricular dilatation, and biological remodeling occurred before a clinically significant fall in ejection fraction.
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Affiliation(s)
- Daniella Corporan
- Structural Heart Research and Innovation Laboratory, Carlyle Fraser Heart Center at Emory University Hospital Midtown, Atlanta, Ga
| | - Daisuke Onohara
- Structural Heart Research and Innovation Laboratory, Carlyle Fraser Heart Center at Emory University Hospital Midtown, Atlanta, Ga
| | - Alan Amedi
- Structural Heart Research and Innovation Laboratory, Carlyle Fraser Heart Center at Emory University Hospital Midtown, Atlanta, Ga
| | - Maher Saadeh
- Structural Heart Research and Innovation Laboratory, Carlyle Fraser Heart Center at Emory University Hospital Midtown, Atlanta, Ga
| | - Robert A Guyton
- Structural Heart Research and Innovation Laboratory, Carlyle Fraser Heart Center at Emory University Hospital Midtown, Atlanta, Ga; Division of Cardiothoracic Surgery, Department of Surgery, Emory University School of Medicine, Atlanta, Ga
| | - Sandeep Kumar
- Department of Biomedical Engineering, Emory University School of Medicine, Atlanta, Ga
| | - Muralidhar Padala
- Structural Heart Research and Innovation Laboratory, Carlyle Fraser Heart Center at Emory University Hospital Midtown, Atlanta, Ga; Division of Cardiothoracic Surgery, Department of Surgery, Emory University School of Medicine, Atlanta, Ga.
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Li S, Nguyen NUN, Xiao F, Menendez-Montes I, Nakada Y, Tan WLW, Anene-Nzelu CG, Foo RS, Thet S, Cardoso AC, Wang P, Elhelaly WM, Lam NT, Pereira AHM, Hill JA, Sadek HA. Mechanism of Eccentric Cardiomyocyte Hypertrophy Secondary to Severe Mitral Regurgitation. Circulation 2020; 141:1787-1799. [PMID: 32272846 DOI: 10.1161/circulationaha.119.043939] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Primary valvular heart disease is a prevalent cause of morbidity and mortality in both industrialized and developing countries. Although the primary consequence of valvular heart disease is myocardial dysfunction, treatment of valvular heart diseases centers around valve repair or replacement rather than prevention or reversal of myocardial dysfunction. This is particularly evident in primary mitral regurgitation (MR), which invariably results in eccentric hypertrophy and left ventricular (LV) failure in the absence of timely valve repair or replacement. The mechanism of LV dysfunction in primary severe MR is entirely unknown. METHODS Here, we developed the first mouse model of severe MR. Valvular damage was achieved by severing the mitral valve leaflets and chords with iridectomy scissors, and MR was confirmed by echocardiography. Serial echocardiography was performed to follow up LV morphology and systolic function. Analysis of cardiac tissues was subsequently performed to evaluate valve deformation, cardiomyocyte morphology, LV fibrosis, and cell death. Finally, dysregulated pathways were assessed by RNA-sequencing analysis and immunofluorescence. RESULTS In the ensuing 15 weeks after the induction of MR, gradual LV dilatation and dysfunction occurred, resulting in severe systolic dysfunction. Further analysis revealed that severe MR resulted in a marked increase in cardiac mass and increased cardiomyocyte length but not width, with electron microscopic evidence of sarcomere disarray and the development of sarcomere disruption. From a mechanistic standpoint, severe MR resulted in activation of multiple components of both the mammalian target of rapamycin and calcineurin pathways. Inhibition of mammalian target of rapamycin signaling preserved sarcomeric structure and prevented LV remodeling and systolic dysfunction. Immunohistochemical analysis uncovered a differential pattern of expression of the cell polarity regulator Crb2 (crumbs homolog 2) along the longitudinal axis of cardiomyocytes and close to the intercalated disks in the MR hearts. Electron microscopy images demonstrated a significant increase in polysome localization in close proximity to the intercalated disks and some areas along the longitudinal axis in the MR hearts. CONCLUSIONS These results indicate that LV dysfunction in response to severe MR is a form of maladaptive eccentric cardiomyocyte hypertrophy and outline the link between cell polarity regulation and spatial localization protein synthesis as a pathway for directional cardiomyocyte growth.
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Affiliation(s)
- Shujuan Li
- Department of Pediatric Cardiology, the First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China (S.L.).,NHC Key Laboratory of Assisted Circulation (Sun Yat-sen University), Guangzhou, China (S.L.).,Department of Internal Medicine, Division of Cardiology (S.L., N.U.N.N., F.X., I.M.-M., Y.N., S.T., A.C.C., P.W., W.M.E., N.T.L., A.H.M.P., J.A.H., H.A.S.), University of Texas Southwestern Medical Center, Dallas
| | - Ngoc Uyen Nhi Nguyen
- Department of Internal Medicine, Division of Cardiology (S.L., N.U.N.N., F.X., I.M.-M., Y.N., S.T., A.C.C., P.W., W.M.E., N.T.L., A.H.M.P., J.A.H., H.A.S.), University of Texas Southwestern Medical Center, Dallas
| | - Feng Xiao
- Department of Internal Medicine, Division of Cardiology (S.L., N.U.N.N., F.X., I.M.-M., Y.N., S.T., A.C.C., P.W., W.M.E., N.T.L., A.H.M.P., J.A.H., H.A.S.), University of Texas Southwestern Medical Center, Dallas
| | - Ivan Menendez-Montes
- Department of Internal Medicine, Division of Cardiology (S.L., N.U.N.N., F.X., I.M.-M., Y.N., S.T., A.C.C., P.W., W.M.E., N.T.L., A.H.M.P., J.A.H., H.A.S.), University of Texas Southwestern Medical Center, Dallas
| | - Yuji Nakada
- Department of Internal Medicine, Division of Cardiology (S.L., N.U.N.N., F.X., I.M.-M., Y.N., S.T., A.C.C., P.W., W.M.E., N.T.L., A.H.M.P., J.A.H., H.A.S.), University of Texas Southwestern Medical Center, Dallas
| | - Wilson Lek Wen Tan
- Cardiovascular Research Institute, National University of Singapore (W.L.W.T., C.G.A.-N., R.S.F.).,Genome Institute of Singapore (W.L.W.T., C.G.A.-N., R.S.F.)
| | - Chukwuemeka George Anene-Nzelu
- Cardiovascular Research Institute, National University of Singapore (W.L.W.T., C.G.A.-N., R.S.F.).,Genome Institute of Singapore (W.L.W.T., C.G.A.-N., R.S.F.)
| | - Roger S Foo
- Cardiovascular Research Institute, National University of Singapore (W.L.W.T., C.G.A.-N., R.S.F.).,Genome Institute of Singapore (W.L.W.T., C.G.A.-N., R.S.F.)
| | - Suwannee Thet
- Department of Internal Medicine, Division of Cardiology (S.L., N.U.N.N., F.X., I.M.-M., Y.N., S.T., A.C.C., P.W., W.M.E., N.T.L., A.H.M.P., J.A.H., H.A.S.), University of Texas Southwestern Medical Center, Dallas
| | - Alisson Campos Cardoso
- Department of Internal Medicine, Division of Cardiology (S.L., N.U.N.N., F.X., I.M.-M., Y.N., S.T., A.C.C., P.W., W.M.E., N.T.L., A.H.M.P., J.A.H., H.A.S.), University of Texas Southwestern Medical Center, Dallas.,Brazilian Biosciences National Laboratory, Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, São Paulo (A.C.C., A.H.M.P.)
| | - Ping Wang
- Department of Internal Medicine, Division of Cardiology (S.L., N.U.N.N., F.X., I.M.-M., Y.N., S.T., A.C.C., P.W., W.M.E., N.T.L., A.H.M.P., J.A.H., H.A.S.), University of Texas Southwestern Medical Center, Dallas
| | - Waleed M Elhelaly
- Department of Internal Medicine, Division of Cardiology (S.L., N.U.N.N., F.X., I.M.-M., Y.N., S.T., A.C.C., P.W., W.M.E., N.T.L., A.H.M.P., J.A.H., H.A.S.), University of Texas Southwestern Medical Center, Dallas
| | - Nicholas T Lam
- Department of Internal Medicine, Division of Cardiology (S.L., N.U.N.N., F.X., I.M.-M., Y.N., S.T., A.C.C., P.W., W.M.E., N.T.L., A.H.M.P., J.A.H., H.A.S.), University of Texas Southwestern Medical Center, Dallas
| | - Ana Helena Macedo Pereira
- Department of Internal Medicine, Division of Cardiology (S.L., N.U.N.N., F.X., I.M.-M., Y.N., S.T., A.C.C., P.W., W.M.E., N.T.L., A.H.M.P., J.A.H., H.A.S.), University of Texas Southwestern Medical Center, Dallas.,Brazilian Biosciences National Laboratory, Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, São Paulo (A.C.C., A.H.M.P.)
| | - Joseph A Hill
- Department of Internal Medicine, Division of Cardiology (S.L., N.U.N.N., F.X., I.M.-M., Y.N., S.T., A.C.C., P.W., W.M.E., N.T.L., A.H.M.P., J.A.H., H.A.S.), University of Texas Southwestern Medical Center, Dallas.,Department of Molecular Biology (J.A.H., H.A.S.), University of Texas Southwestern Medical Center, Dallas
| | - Hesham A Sadek
- Department of Internal Medicine, Division of Cardiology (S.L., N.U.N.N., F.X., I.M.-M., Y.N., S.T., A.C.C., P.W., W.M.E., N.T.L., A.H.M.P., J.A.H., H.A.S.), University of Texas Southwestern Medical Center, Dallas.,Center for Regenerative Science and Medicine (H.A.S.), University of Texas Southwestern Medical Center, Dallas.,Department of Molecular Biology (J.A.H., H.A.S.), University of Texas Southwestern Medical Center, Dallas
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Li B, Cui Y, Zhang D, Luo X, Luo F, Li B, Tang Y. The characteristics of a porcine mitral regurgitation model. Exp Anim 2018; 67:463-477. [PMID: 29794373 PMCID: PMC6219876 DOI: 10.1538/expanim.18-0045] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The porcine mitral regurgitation (MR) model is a common cardiovascular animal model.
Standardized manufacturing processes can improve the uniformity and success rate of the
model, and systematic research can evaluate its potential use. In this study, 17 pigs were
divided into an experimental group (n=11) and a control group (n=6). We used a homemade
retractor to cut the mitral chordae via the left atrial appendage to establish a model of
MR; the control group underwent a sham surgery. The model animals were followed for 30
months after the surgery. Enlargement and fibrosis of the left atrium were significant in
the experimental group compared with those in the control group, and left atrial systolic
function decreased significantly. In addition, model animals showed preserved left
ventricular systolic function. There were no differences in left atrial potential or left
ventricular myocardial fibrosis between the two groups. Atrial fibrillation susceptibility
in the experimental group was higher than that in the control group. Our method enables
the simple and effective production of a MR model with severe reflux that can be used for
pathophysiological studies of MR, as well as for the development of preclinical surgical
instruments and their evaluation. This model could also be used to study atrial
fibrillation and myocardial fibrosis but is not suitable for studies of heart failure.
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Affiliation(s)
- Bo 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, No.167 North lishi Road, Xicheng District, Beijing 100037, China
| | - Yongchun Cui
- 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, No.167 North lishi Road, Xicheng District, Beijing 100037, China
| | - Dong Zhang
- Department of Cardiovascular surgery, Beijing Jishuitan Hospital, No. 31 Xinjiekou East Street, Xicheng District, Beijing 100035, China
| | - Xiaokang Luo
- 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, No.167 North lishi Road, Xicheng District, Beijing 100037, China
| | - Fuliang Luo
- 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, No.167 North lishi Road, Xicheng District, Beijing 100037, 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, No.167 North lishi Road, Xicheng District, Beijing 100037, 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, No.167 North lishi Road, Xicheng District, Beijing 100037, China
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