Reconstruction of the patterns of gene expression in the developing mouse heart reveals an architectural arrangement that facilitates the understanding of atrial malformations and arrhythmias.
Firm knowledge about the formation of the atrial components and of the variations seen in congenital cardiac malformations and abnormal atrial rhythms is fundamental to our understanding of the normal structure of the definitive atrial chambers. The atrial region is relatively inaccessible and has continued to be the source of disagreement. Seeking to resolve these controversies, we made three-dimensional reconstructions of the myocardial components of the developing atrium, identifying domains on the basis of differential expression of myocardial markers, connexin40, and natriuretic precursor peptide A. These reconstructions, made from serial sections of mouse embryos, show that from the outset of atrial development, the systemic and pulmonary veins are directly connected to the atrium. Relative to the systemic junctions, however, the pulmonary venous junction appears later. Our experience shows that three-dimensional reconstructions have three advantages. First, they provide clear access to the combined morphological and molecular data, allowing clarification and verification of morphogenetic concepts for nonmorphological experts and setting the scene for further discussion. Second, they demonstrate that, from the outset, the myocardium surrounding the pulmonary veins is distinct from that clothing the systemic venoatrial junctions. Third, they reveal an anatomical and molecular continuity between the entrance of the systemic venous tributaries, the internodal atrial myocardium, and the atrioventricular region. All these regions are derived from primary myocardium, providing a molecular basis for the observed nonrandom distribution of focal right atrial tachycardias.
Soufan
Alexandre T
AT
Experimental and Molecular Cardiology Group, Academic Medical Centre, University of Amsterdam, The Netherlands.
van den Hoff
Maurice J B
MJ
Ruijter
Jan M
JM
de Boer
Piet A J
PA
Hagoort
Jaco
J
Webb
Sandra
S
Anderson
Robert H
RH
Moorman
Antoon F M
AF
D000818:Animals; D020517:Atrial Appendage / Q000196:embryology / Q000378:metabolism; D009320:Atrial Natriuretic Factor; D017630:Connexins / Q000032:analysis / Q000096:biosynthesis / Q000235:genetics*; D005318:Fetal Heart / Q000033:anatomy & histology / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental; D005865:Gestational Age; D006325:Heart Atria / Q000196:embryology* / Q000378:metabolism; D006329:Heart Conduction System / Q000196:embryology*; D008648:Mesoderm / Q000648:ultrastructure; D051379:Mice; D008953:Models, Anatomic; D009206:Myocardium / Q000737:chemistry / Q000166:cytology / Q000378:metabolism; D020098:Natriuretic Peptide, C-Type / Q000032:analysis / Q000096:biosynthesis / Q000235:genetics*; D011498:Protein Precursors / Q000032:analysis / Q000096:biosynthesis / Q000235:genetics*; D011667:Pulmonary Veins / Q000196:embryology* / Q000378:metabolism; D013194:Staining and Labeling; D013612:Tachycardia, Ectopic Atrial / Q000196:embryology / Q000209:etiology* / Q000473:pathology; D000097003:Gap Junction alpha-5 Protein
D009320:Atrial Natriuretic Factor; D017630:Connexins; D020098:Natriuretic Peptide, C-Type; D011498:Protein Precursors; D000097003:Gap Junction alpha-5 Protein; C431578:Nppa protein, mouse