Epicardial-like cells on the distal arterial end of the cardiac outflow tract do not derive from the proepicardium but are derivatives of the cephalic pericardium

Authors

  • José M. Pérez-Pomares,

    1. Department of Cell Biology and Anatomy, Cardiovascular Developmental Biology Center, Medical University of South Carolina, Charleston, South Carolina
    2. Department of Animal Biology, Faculty of Science, University of Málaga, Málaga, Spain
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  • Aimée Phelps,

    1. Department of Cell Biology and Anatomy, Cardiovascular Developmental Biology Center, Medical University of South Carolina, Charleston, South Carolina
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  • Martina Sedmerova,

    1. Department of Cell Biology and Anatomy, Cardiovascular Developmental Biology Center, Medical University of South Carolina, Charleston, South Carolina
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  • Andy Wessels

    Corresponding author
    1. Department of Cell Biology and Anatomy, Cardiovascular Developmental Biology Center, Medical University of South Carolina, Charleston, South Carolina
    • Department of Cell Biology and Anatomy and Cardiovascular Developmental Biology Center, Medical University of South Carolina, 173 Ashley Avenue, Basic Science Building, Room 648, P.O. Box 250508, Charleston, SC 29425
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Abstract

A series of recent studies strongly suggests that the myocardium of the cardiac distal outflow tract (d-OFT) does not derive from the original precardiac mesoderm but, instead, differentiates from a so-called anterior heart field. Similar findings were also reported for the endocardium of the d-OFT. However, very little information is available on the origin of the epicardium of the OFT. To address this issue, we have performed a study in which we have combined experimental in vivo and in vitro techniques (construction of proepicardial chimeras, proepicardial ablation, OFT insertion of eggshell membrane pieces, and culture on collagen gels) with molecular characterization techniques to determine this origin and define the properties of d-OFT epicardium compared with proepicardially derived epicardium. Our results demonstrate that the coelomic/pericardial epithelium in the vicinity of the aortic sac (and not the proepicardium) is the origin of d-OFT epicardium. This “pericardially” derived epicardium and the proepicardially derived epicardial tissues differ in their morphologic appearance, gene-expression profile, and in their ability to undergo epithelial-to-mesenchymal transformation. We conclude that the heterogeneity in the epicardial cell population of the OFT could be a factor in the complex developmental remodeling events at the arterial pole of the heart. Developmental Dynamics 227:56–68, 2003. © 2003 Wiley-Liss, Inc.

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