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Klein V, Coll-Font J, Vendramini L, Straney D, Davids M, Ferris NG, Schad LR, Sosnovik DE, Nguyen CT, Wald LL, Guérin B. Measurement of magnetostimulation thresholds in the porcine heart. Magn Reson Med 2022; 88:2242-2258. [PMID: 35906903 PMCID: PMC9420805 DOI: 10.1002/mrm.29382] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2022] [Revised: 05/26/2022] [Accepted: 06/18/2022] [Indexed: 11/09/2022]
Abstract
PURPOSE Powerful MRI gradient systems can surpass the International Electrotechnical Commission (IEC) 60601-2-33 limit for cardiac stimulation (CS), which was determined by simple electromagnetic simulations and electrode stimulation experiments. Only a few canine studies measured magnetically induced CS thresholds in vivo and extrapolating them to human safety limits can be challenging. METHODS We measured cardiac magnetostimulation thresholds in 10 healthy, anesthetized pigs using capacitors discharged into a flat spiral coil to produce damped sinusoidal waveforms with effective stimulus duration ts,eff = 0.45 ms. Electrocardiography (ECG), blood pressure, and peripheral oximetry signals were recorded to determine threshold coil currents yielding cardiac capture. Dixon and CINE MR volumes from each animal were segmented to generate porcine-specific electromagnetic models to calculate dB/dt and E-field values in the porcine heart at threshold. For comparison, we also simulated maximum dB/dt and E-field values created by three MRI gradient systems in the heart of a human body model. RESULTS The average dB/dt threshold estimated in the porcine heart was 1.66 ± 0.23 kT/s, which is 11-fold greater than the IEC dB/dt limit at ts,eff = 0.45 ms, and 31-fold greater than the maximum value created by the investigated MRI gradients in the human heart. The average E-field threshold estimated in the porcine heart was 92.9 ± 13.5 V/m, which is 6-fold greater than the IEC E-field limit at ts,eff = 0.45 ms and 37-fold greater than the maximum gradient-induced E-field in the human heart. CONCLUSION This first measurement of cardiac magnetostimulation thresholds in pigs indicates that the IEC cardiac safety limit is conservative for the investigated stimulus duration (ts,eff = 0.45 ms).
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Affiliation(s)
- Valerie Klein
- Computer Assisted Clinical Medicine, Medical Faculty Mannheim, Heidelberg University, Heidelberg, Germany
- A. A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA, United States
| | - Jaume Coll-Font
- A. A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA, United States
- Harvard Medical School, Boston, MA, United States
- Cardiovascular Research Center, Cardiology Division, Massachusetts General Hospital, Charlestown, MA
| | - Livia Vendramini
- A. A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA, United States
| | - Donald Straney
- A. A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA, United States
| | - Mathias Davids
- Computer Assisted Clinical Medicine, Medical Faculty Mannheim, Heidelberg University, Heidelberg, Germany
- A. A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA, United States
- Harvard Medical School, Boston, MA, United States
| | - Natalie G. Ferris
- A. A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA, United States
- Harvard-MIT Division of Health Sciences and Technology, Cambridge, MA, United States
- Harvard Biophysics Graduate Program, Cambridge, MA, United States
| | - Lothar R. Schad
- Computer Assisted Clinical Medicine, Medical Faculty Mannheim, Heidelberg University, Heidelberg, Germany
| | - David E. Sosnovik
- A. A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA, United States
- Harvard Medical School, Boston, MA, United States
- Cardiovascular Research Center, Cardiology Division, Massachusetts General Hospital, Charlestown, MA
- Harvard-MIT Division of Health Sciences and Technology, Cambridge, MA, United States
| | - Christopher T. Nguyen
- A. A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA, United States
- Harvard Medical School, Boston, MA, United States
- Cardiovascular Research Center, Cardiology Division, Massachusetts General Hospital, Charlestown, MA
- Harvard-MIT Division of Health Sciences and Technology, Cambridge, MA, United States
| | - Lawrence L. Wald
- A. A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA, United States
- Harvard Medical School, Boston, MA, United States
- Harvard-MIT Division of Health Sciences and Technology, Cambridge, MA, United States
- Harvard Biophysics Graduate Program, Cambridge, MA, United States
| | - Bastien Guérin
- A. A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA, United States
- Harvard Medical School, Boston, MA, United States
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Shati AA, Zaki MSA, Alqahtani YA, Al-Qahtani SM, Haidara MA, Dawood AF, AlMohanna AM, El-Bidawy MH, Alaa Eldeen M, Eid RA. Antioxidant Activity of Vitamin C against LPS-Induced Septic Cardiomyopathy by Down-Regulation of Oxidative Stress and Inflammation. Curr Issues Mol Biol 2022; 44:2387-2400. [PMID: 35678692 PMCID: PMC9164034 DOI: 10.3390/cimb44050163] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Revised: 05/19/2022] [Accepted: 05/20/2022] [Indexed: 12/02/2022] Open
Abstract
In severe cases of sepsis, endotoxin-induced cardiomyopathy can cause major damage to the heart. This study was designed to see if Vitamin C (Vit C) could prevent lipopolysaccharide-induced heart damage. Eighteen Sprague Dawley male rats (n = 6) were divided into three groups. Rats received 0.5 mL saline by oral gavage in addition to a standard diet (Control group), rats received one dose of endotoxin on day 15 (lipopolysaccharide) (LPS) (6 mg/kg), which produced endotoxemia (Endotoxin group), and rats that received 500 mg/Kg BW of Vit C by oral gavage for 15 days before LPS administration (Endotoxin plus Vit C group). In all groups, blood and tissue samples were collected on day 15, six hours after LPS administration, for histopathological and biochemical analysis. The LPS injection lowered superoxide dismutase (SOD) levels and increased malondialdehyde in tissues compared with a control group. Furthermore, the endotoxin group showed elevated inflammatory biomarkers, tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6). Both light and electron microscopy showed that the endotoxic-treated group’s cardiomyocytes, intercalated disks, mitochondria, and endothelial cells were damaged. In endotoxemic rats, Vit C pretreatment significantly reduced MDA levels and restored SOD activity, minimized biomarkers of inflammation, and mitigated cardiomyocyte damage. In conclusion: Vit C protects against endotoxin-induced cardiomyopathy by inhibiting oxidative stress cytokines.
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Affiliation(s)
- Ayed A. Shati
- Department of Child Health, College of Medicine, King Khalid University, Abha P.O. Box 62529, Saudi Arabia; (A.A.S.); (Y.A.A.); (S.M.A.-Q.)
| | - Mohamed Samir A. Zaki
- Anatomy Department, College of Medicine, King Khalid University, Abha P.O. Box 62529, Saudi Arabia;
- Department of Histology and Cell Biology, College of Medicine, Zagazig University, Zagazig 31527, Egypt
| | - Youssef A. Alqahtani
- Department of Child Health, College of Medicine, King Khalid University, Abha P.O. Box 62529, Saudi Arabia; (A.A.S.); (Y.A.A.); (S.M.A.-Q.)
| | - Saleh M. Al-Qahtani
- Department of Child Health, College of Medicine, King Khalid University, Abha P.O. Box 62529, Saudi Arabia; (A.A.S.); (Y.A.A.); (S.M.A.-Q.)
| | - Mohamed A. Haidara
- Department of Physiology, Kasr Al-Aini College of Medicine, Cairo University, Cairo 11519, Egypt; (M.A.H.); (M.H.E.-B.)
| | - Amal F. Dawood
- Department of Basic Medical Sciences, College of Medicine, Princess Nourah Bint Abdulrahman University, Riyadh P.O. Box 84428, Saudi Arabia; (A.F.D.); (A.M.A.)
| | - Asmaa M. AlMohanna
- Department of Basic Medical Sciences, College of Medicine, Princess Nourah Bint Abdulrahman University, Riyadh P.O. Box 84428, Saudi Arabia; (A.F.D.); (A.M.A.)
| | - Mahmoud H. El-Bidawy
- Department of Physiology, Kasr Al-Aini College of Medicine, Cairo University, Cairo 11519, Egypt; (M.A.H.); (M.H.E.-B.)
- Department of BMS, Division of Physiology, College of Medicine, Prince Sattam Bin Abdulaziz University, Al-Kharj P.O. Box 11942, Saudi Arabia
| | - Muhammad Alaa Eldeen
- Cell Biology, Histology & Genetics Division, Zoology Department, College of Science, Zagazig University, Zagazig 44519, Egypt;
| | - Refaat A. Eid
- Pathology Department, College of Medicine, King Khalid University, Abha P.O. Box 62529, Saudi Arabia
- Correspondence: or
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Sutanto H, Heijman J. Integrative Computational Modeling of Cardiomyocyte Calcium Handling and Cardiac Arrhythmias: Current Status and Future Challenges. Cells 2022; 11:1090. [PMID: 35406654 PMCID: PMC8997666 DOI: 10.3390/cells11071090] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Revised: 03/22/2022] [Accepted: 03/22/2022] [Indexed: 12/26/2022] Open
Abstract
Cardiomyocyte calcium-handling is the key mediator of cardiac excitation-contraction coupling. In the healthy heart, calcium controls both electrical impulse propagation and myofilament cross-bridge cycling, providing synchronous and adequate contraction of cardiac muscles. However, calcium-handling abnormalities are increasingly implicated as a cause of cardiac arrhythmias. Due to the complex, dynamic and localized interactions between calcium and other molecules within a cardiomyocyte, it remains experimentally challenging to study the exact contributions of calcium-handling abnormalities to arrhythmogenesis. Therefore, multiscale computational modeling is increasingly being used together with laboratory experiments to unravel the exact mechanisms of calcium-mediated arrhythmogenesis. This article describes various examples of how integrative computational modeling makes it possible to unravel the arrhythmogenic consequences of alterations to cardiac calcium handling at subcellular, cellular and tissue levels, and discusses the future challenges on the integration and interpretation of such computational data.
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