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High-Resolution Endocardial and Epicardial Optical Mapping in a Sheep Model of Stretch-Induced Atrial Fibrillation
Published on: July 29, 2011
Novel insights into the cellular basis of atrial fibrillation
1Penn Cardiovascular Institute and Division of Cardiovascular Medicine, 905 BRB II/III, 421 Curie Boulevard, University of Pennsylvania, Philadelphia, PA 19104-6160, USA. patelv@mail.med.upenn.edu
Insights
New research identifies cardiac melanocyte-like cells as a potential source of atrial arrhythmias. These cells, expressing dopachrome tautomerase (Dct), may trigger atrial fibrillation, a common heart rhythm disorder.
Area of Science:
- Cardiology
- Electrophysiology
- Cell Biology
Background:
- Atrial fibrillation is a prevalent cardiac arrhythmia often triggered by ectopic beats from pulmonary veins and atria.
- While pulmonary vein myocytes are primary contributors, other cell types may also initiate atrial arrhythmias.
- A novel melanocyte-like cell population in the heart has been identified as a potential contributor.
Purpose of the Study:
- To investigate the role of cardiac melanocyte-like cells in atrial arrhythmias.
- To determine if these cells contribute to atrial arrhythmogenic triggers.
- To explore the expression of dopachrome tautomerase (Dct) in these cells and its relation to arrhythmias.
Main Methods:
- Characterization of melanocyte-like cells in murine and human hearts.
- Assessment of electrical excitability and receptor expression in murine cardiac melanocyte-like cells.
- Analysis of atrial arrhythmia susceptibility in adult mice lacking the dopachrome tautomerase (Dct) gene.
Main Results:
- Murine cardiac melanocyte-like cells are electrically excitable and express adrenergic and muscarinic receptors.
- Mice lacking Dct exhibit susceptibility to atrial arrhythmias.
- Dopachrome tautomerase (Dct) is expressed by both murine and human cardiac melanocytes, and these cells are found in regions associated with atrial arrhythmias.
Conclusions:
- Cardiac melanocyte-like cells represent a novel cell population potentially involved in atrial arrhythmias.
- Dopachrome tautomerase (Dct) expression in these cells suggests a role in cardiac electrophysiology.
- Further research is needed to determine the contribution of these cells to clinical atrial fibrillation.
Abstract:
Atrial fibrillation is the most common clinical cardiac arrhythmia. It is often initiated by ectopic beats arising from the pulmonary veins and atria. While pulmonary vein myocytes most likely contribute to atrial ectopic beats initiating atrial fibrillation, emerging evidence suggests the existence of other cell populations that may also contribute to atrial arrhythmias. In addition to sinus node-like and intestinal Cajal-like cells, we recently characterized a novel, melanocyte-like cell population in murine and human hearts that may contribute to atrial arrhythmogenic triggers in mice. Murine cardiac melanocyte-like cells are electrically excitable, and express adrenergic and muscarinic receptors. Adult mice lacking the gene encoding dopachrome tautomerase (Dct) are susceptible to atrial arrhythmias, and Dct is expressed by both murine and human cardiac melanocytes. While Dct-expressing cells are present in human hearts in regions from which atrial arrhythmias often arise, the contribution of these cells to clinical atrial arrhythmias remains to be determined.
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