1
|
Adeniran I, Wadee H, Degens H. An In Silico Cardiomyocyte Reveals the Impact of Changes in CaMKII Signalling on Cardiomyocyte Contraction Kinetics in Hypertrophic Cardiomyopathy. BIOMED RESEARCH INTERNATIONAL 2024; 2024:6160554. [PMID: 38567164 PMCID: PMC10985279 DOI: 10.1155/2024/6160554] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Figures] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Revised: 02/27/2024] [Accepted: 03/09/2024] [Indexed: 04/04/2024]
Abstract
Hypertrophic cardiomyopathy (HCM) is characterised by asymmetric left ventricular hypertrophy, ventricular arrhythmias, and cardiomyocyte dysfunction that may cause sudden death. HCM is associated with mutations in sarcomeric proteins and is usually transmitted as an autosomal-dominant trait. The aim of this in silico study was to assess the mechanisms that underlie the altered electrophysiological activity, contractility, regulation of energy metabolism, and crossbridge cycling in HCM at the single-cell level. To investigate this, we developed a human ventricular cardiomyocyte model that incorporates electrophysiology, metabolism, and force generation. The model was validated by its ability to reproduce the experimentally observed kinetic properties of human HCM induced by (a) remodelling of several ion channels and Ca2+-handling proteins arising from altered Ca2+/calmodulin kinase II signalling pathways and (b) increased Ca2+ sensitivity of the myofilament proteins. Our simulation showed a decreased phosphocreatine-to-ATP ratio (-9%) suggesting a negative mismatch between energy expenditure and supply. Using a spatial myofilament half-sarcomere model, we also compared the fraction of detached, weakly bound, and strongly bound crossbridges in the control and HCM conditions. Our simulations showed that HCM has more crossbridges in force-producing states than in the control condition. In conclusion, our model reveals that impaired crossbridge kinetics is accompanied by a negative mismatch between the ATP supply and demand ratio. This suggests that improving this ratio may reduce the incidence of sudden death in HCM.
Collapse
Affiliation(s)
- Ismail Adeniran
- Centre for Advanced Computational Science, Manchester Metropolitan University, Manchester M15 6BH, UK
| | - Hafsa Wadee
- Centre for Advanced Computational Science, Manchester Metropolitan University, Manchester M15 6BH, UK
| | - Hans Degens
- Department of Life Sciences, Manchester Metropolitan University, Manchester M15 6BH, UK
- Lithuanian Sports University, Sporto 6, LT-44221 Kaunas, Lithuania
| |
Collapse
|
2
|
Xu P, Liu W, Qian W, Wang J, Wang Y, Zhou X, Zhu Y, Xu Y, Zhu X. Increase in skeletal muscle extracellular volume as an under-recognised change detected at cardiac MRI in hypertrophic cardiomyopathy. Clin Radiol 2023; 78:e401-e408. [PMID: 36890013 DOI: 10.1016/j.crad.2023.02.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Revised: 01/04/2023] [Accepted: 02/07/2023] [Indexed: 02/24/2023]
Abstract
AIM To explore skeletal muscle change and its correlation with the myocardium in hypertrophic cardiomyopathy (HCM) using cardiac magnetic resonance imaging (cMRI) with T1 mapping and late gadolinium enhancement (LGE). MATERIALS AND METHODS This retrospective study enrolled 50 HCM patients and 35 healthy controls. The extracellular volume (ECV) of the skeletal muscle and myocardium, the presence and absence of LGE of the myocardium, and cardiac troponin T (cTnT), were assessed. In the HCM group, the elevated ECVskeletal group was defined as ECVskeletal >2 standard deviations (SD) above the mean value of the controls. Statistical analyses included Student's t-test, the Mann-Whitney U-test, and linear regression. RESULTS ECVskeletal in the HCM group was higher than in the control group (mean 13.0 versus 10.9%; p<0.001), with 20 (40%) HCM patients having elevated ECVskeletal (ECVskeletal ≥13.7%). In the HCM group, ECVskeletal had a positive linear correlation with global myocardial ECV (r=0.37, p=0.009). In addition, the elevated ECVskeletal group had a higher cTnT than the non-elevated group (log cTnT, mean 1.55 versus 1.16, p=0.045). Furthermore, segmental myocardial ECV in the elevated ECVskeletal group was higher than in the non-elevated group, despite the presence or absence of myocardial LGE (median 30.1 versus 27.2%; 26.5 versus 24.6%, both p<0.001) or hypertrophy (median 29.0 versus 26.0%; 26.8 versus 24.8%, both p<0.001). CONCLUSION In the HCM patients, ECVskeletal was higher than in the healthy controls. Furthermore, some ECVskeletal changes had corresponding changes in the cTnT and myocardium.
Collapse
Affiliation(s)
- P Xu
- Department of Radiology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, 210029, China
| | - W Liu
- Department of Radiology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, 210029, China
| | - W Qian
- Department of Radiology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, 210029, China
| | - J Wang
- Department of Radiology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, 210029, China
| | - Y Wang
- Department of Radiology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, 210029, China
| | - X Zhou
- MR Collaboration, Siemens Healthineers, Shanghai, China
| | - Y Zhu
- Department of Radiology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, 210029, China
| | - Y Xu
- Department of Radiology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, 210029, China
| | - X Zhu
- Department of Radiology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, 210029, China.
| |
Collapse
|
3
|
The Primary Alteration of Ventricular Myocardium Conduction: The Significant Determinant of Left Bundle Branch Block Pattern. Cardiol Res Pract 2022; 2022:3438603. [PMID: 36589707 PMCID: PMC9800102 DOI: 10.1155/2022/3438603] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/12/2022] [Revised: 12/06/2022] [Accepted: 12/08/2022] [Indexed: 12/24/2022] Open
Abstract
Intraventricular conduction disturbances (IVCD) are currently generally accepted as ECG diagnostic categories. They are characterized by defined QRS complex patterns that reflect the abnormalities in the intraventricular sequence of activation that can be caused by pathology in the His-Purkinje conduction system (HP) or ventricular myocardium. However, the current understanding of the IVCD's underlying mechanism is mostly attributed to HP structural or functional alterations. The involvement of the working ventricular myocardium is only marginally mentioned or not considered. This opinion paper is focused on the alterations of the ventricular working myocardium leading to the most frequent IVCD pattern-the left bundle branch block pattern (LBBB). Recognizing the underlying mechanisms of the LBBB patterns and the involvement of the ventricular working myocardium is of utmost clinical importance, considering a patient's prognosis and indication for cardiac resynchronization therapy.
Collapse
|
4
|
Scherba JC, Halushka MK, Andersen ND, Maleszewski JJ, Landstrom AP, Bursac N, Glass C. BRG1 is a biomarker of hypertrophic cardiomyopathy in human heart specimens. Sci Rep 2022; 12:7996. [PMID: 35581268 PMCID: PMC9114001 DOI: 10.1038/s41598-022-11829-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Accepted: 04/18/2022] [Indexed: 11/27/2022] Open
Abstract
Hypertrophic cardiomyopathy (HCM) is a genetic disease of the sarcomere that causes otherwise unexplained cardiac hypertrophy and is associated with sudden death. While previous studies showed the role of the epigenetic modifier Brg1 in mouse models of HCM, additional work is needed to identify its role in humans. We tested the hypothesis that BRG1 expression is increased in periods of cardiac remodeling during fetal growth and in development of HCM. We employed immunohistochemical staining to evaluate protein expression of BRG1 in 796 human cardiac specimens (81 from patients with HCM) and describe elevated BRG1 expression in human fetal hearts in early development. In addition, we not only demonstrate increased expression of BRG1 in HCM, but we also show that other diseases that lead to heart failure have similar BRG1 expression to healthy controls. Inhibition of BRG1 in human induced pluripotent stem cell-derived cardiomyocytes significantly decreases MYH7 and increases MYH6, suggesting a regulatory role for BRG1 in the pathological imbalance of the two myosin heavy chain isoforms in human HCM. These data are the first demonstration of BRG1 as a specific biomarker for human HCM and provide foundation for future studies of epigenetics in human cardiac disease.
Collapse
Affiliation(s)
- Jacob C Scherba
- Department of Biomedical Engineering, Duke University, Durham, NC, 27710, USA
| | - Marc K Halushka
- Department of Pathology, Johns Hopkins Medical Institutions, Baltimore, MD, 21287, USA
| | - Nicholas D Andersen
- Division of Cardiovascular and Thoracic Surgery, Department of Surgery, Duke University Medical Center, Durham, NC, 27710, USA
| | - Joseph J Maleszewski
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, 55905, USA
| | - Andrew P Landstrom
- Division of Pediatric Cardiology, Department of Pediatrics, Duke University Medical Center, Durham, NC, 27710, USA
| | - Nenad Bursac
- Department of Biomedical Engineering, Duke University, Durham, NC, 27710, USA
| | - Carolyn Glass
- Department of Pathology, Duke University Medical Center, 217AM Davison Bldg, 40 Duke Medicine Circle, Box 3712 DUHS, Durham, NC, 27710, USA.
| |
Collapse
|