title: Endothelial outgrowth and the subsequent cell transition in the culture of embryonic atrioventricular canal placed in an inverted polarity.
abstract: Endothelial cells in the atrioventricular (AV) segment of the developing chicken heart undergo a transition into mesenchymal cells. When the AV segment is explanted onto a hydrated collagen gel, endothelial cells grow out and reproduce in vivo cell transition regardless of the precise orientation of the explant on a gel. Our results showed that when the luminal side of an explant was placed towards a gel surface, the inverted polarity of endothelium was not adjusted by direct reorganization of polarity, but that the endothelium crawled down so as to settle on a gel surface in the correct original cell polarity. Subsequently, endothelial cells showed cytoplasmic hypertrophy, formed microvillous projections and then extended filopodial migratory appendages. These cellular changes were quite similar to those in vivo. However, the continuity of the endothelial layer was specifically disrupted in AV explant cultures. Such disruption was never observed in ventricle explant cultures in which endothelial-mesenchymal cell transition did not occur. The disintegration of AV endothelial outgrowth must be closely related to its capability to transform into mesenchymal cells and mitotic activity to keep a depository of endothelial cells.
authors.affiliation: Division of Electron Microscopy, Nihon University School of Dentistry, Tokyo, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Isokawa
authors.forename: J
authors.initials: J
authors.lastname: Yi
authors.forename: H
authors.initials: H
authors.lastname: Sejima
authors.forename: M
authors.initials: M
authors.lastname: Tanaka
authors.forename: K
authors.initials: K
authors.lastname: Murakami
authors.forename: H
authors.initials: H
authors.lastname: Yokoyama
authors.forename: S
authors.initials: S
authors.lastname: Endo
authors.forename: T
authors.initials: T
authors.lastname: Komiyama
authors.forename: Y
authors.initials: Y
authors.lastname: Toda
mesh_terms: D000818:Animals; D018929:Cell Culture Techniques; D002454:Cell Differentiation; D002465:Cell Movement; D016764:Cell Polarity; D002642:Chick Embryo; D003094:Collagen; D004727:Endothelium / Q000166:cytology*; D006346:Heart Septum / Q000196:embryology; D006351:Heart Valves / Q000196:embryology*; D006352:Heart Ventricles / Q000196:embryology*; D008648:Mesoderm / Q000166:cytology*; D009206:Myocardium / Q000166:cytology
chemical_list: D003094:Collagen