This Article Full Text Full Text (PDF) All Versions of this Article: 99/4/351    most recent 01.RES.0000238360.33284.a0v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Mommersteeg, M. T.M. Articles by Moorman, A. F.M. Search for Related Content PubMed PubMed Citation Articles by Mommersteeg, M. T.M. Articles by Moorman, A. F.M.

(Circulation Research. 2006;99:351.)
© 2006 American Heart Association, Inc.

Report

Two Distinct Pools of Mesenchyme Contribute to the Development of the Atrial Septum

Mathilda T.M. Mommersteeg, Alexandre T. Soufan, Frederik J. de Lange, Maurice J.B. van den Hoff, Robert H. Anderson, Vincent M. Christoffels, Antoon F.M. Moorman

From the Molecular and Experimental Cardiology Group (M.T.M.M., A.T.S., F.J.d.L., M.J.B.v.d.H., V.M.C., A.F.M.M.), Academic Medical Centre, University of Amsterdam, the Netherlands; and the Cardiac Unit, Institute of Child Health (R.H.A.), University College, London, United Kingdom.

Correspondence to Antoon F.M. Moorman, PhD, Department of Anatomy & Embryology, Academic Medical Centre, Meibergdreef 15, 1105 AZ, Amsterdam, the Netherlands. E-mail a.f.moorman{at}amc.uva.nl

Closure of the primary atrial foramen is achieved by fusion of the atrioventricular cushions with the mesenchymal cap on the leading edge of the muscular primary atrial septum. A fourth component involved is the vestibular spine, originally described by His in 1880 as an intra-cardiac continuation of the extra-cardiac mesenchyme of the dorsal mesocardium. The morphogenesis of this area is of great clinical interest, because of the high incidence of atrial and atrioventricular septal defects. Nonetheless, the origin of the participating components is largely unknown. Here we report that the primary atrial foramen is surrounded in its entirety by mesenchyme derived from endocardium. A second population of mesenchyme not derived from endocardium was observed at the caudal margin of the mesenchymal atrial cap, entirely embedded within the mesenchyme derived from endocardium and contiguous with the mesenchyme of the dorsal mesocardium. Our reconstructions show this second population does indeed take the form of a short spine, albeit that it is the right pulmonary ridge, rather than this spine, that protrudes into the atrial lumen. From the stance of morphological description, therefore, there is little thus far to substantiate the existence of an atrial spine.

Key Words: spina vestibuli • atrial septation • embryology • heart development • 3D visualization

This article has been cited by other articles:

				M. M. Goddeeris, S. Rho, A. Petiet, C. L. Davenport, G. A. Johnson, E. N. Meyers, and J. Klingensmith Intracardiac septation requires hedgehog-dependent cellular contributions from outside the heart Development, May 15, 2008; 135(10): 1887 - 1895. [Abstract] [Full Text] [PDF]

				B. S. Snarr, J. L. O'Neal, M. R. Chintalapudi, E. E. Wirrig, A. L. Phelps, S. W. Kubalak, and A. Wessels Isl1 Expression at the Venous Pole Identifies a Novel Role for the Second Heart Field in Cardiac Development Circ. Res., November 9, 2007; 101(10): 971 - 974. [Abstract] [Full Text] [PDF]