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Noninvasive Assessment of Cardiac Abnormalities in Experimental Autoimmune Myocarditis by Magnetic Resonance Microscopy Imaging in the Mouse
Published on: June 20, 2014
Cardiac dysfunction in murine autoimmune myocarditis
H Less1, M Shilkrut, I Rubinstein
1Rappaport Family Institute for Research in the Medical Sciences, Bruce Rappaport Faculty of Medicine, The Bernard Katz Minerva Center for Cell Biophysics, Technion-Israel Institute of Technology, Haifa, 31096, Israel.
Autoimmune myocarditis in mice impairs cardiac function by altering ventricular myocyte electrophysiology. Reduced transient outward current (Ito) and faster calcium handling contribute to dysfunction in this cardiac disease model.
Area of Science:
- Cardiology
- Immunology
- Physiology
Background:
- Autoimmune myocarditis can lead to dilated cardiomyopathy, a significant cause of cardiac dysfunction.
- Understanding the cellular mechanisms underlying this dysfunction is crucial for developing targeted therapies.
Purpose of the Study:
- To investigate the pathophysiological basis of cardiac dysfunction in autoimmune myocarditis.
- To identify specific electrophysiological and mechanical alterations in ventricular myocytes.
Main Methods:
- Utilized a myosin-induced autoimmune myocarditis model in BALB/c mice.
- Employed whole-cell voltage clamp techniques to analyze ion currents in isolated ventricular myocytes.
- Measured intracellular calcium ([Ca2+]i) transients and myocyte contraction simultaneously.
Main Results:
- Diseased myocytes exhibited significantly prolonged action potential duration (APD80) and attenuated transient outward current (Ito).
- L-type calcium current (ICa,L) remained unchanged, while [Ca2+]i transient and myocyte contraction relaxation kinetics were faster in diseased myocytes.
- Significant lymphocyte infiltration and reduced tail artery blood flow were observed in myocarditis.
Conclusions:
- Electrophysiological and mechanical perturbations in ventricular myocytes contribute to cardiac dysfunction in autoimmune myocarditis.
- These cellular changes, particularly Ito current reduction and altered calcium handling, are potentially reversible.
- The findings provide insights into the mechanisms of heart failure in autoimmune cardiac conditions.
