Spatiotemporally restricted developmental alterations in the anterior and secondary heart fields cause distinct conotruncal heart defects

Abstract

During the early heart development, heart outflow tract elongates by the addition of cardiomyocytes from the anterior heart field (AHF)/secondary heart field (SHF). Dye-marking experiments in early chick embryos clarified that each AHF/SHF migrates to distinct conotruncal regions. Local administration of retinoic acid to the AHF/SHF causes distinct conotruncal heart defects in a region and stage dependent manner. For example, impaired development of AHF at HH stage 12 (corresponding to Carnegie stages 10-11 in human embryos) causes dextroposed aorta including transposition of the great arteries (TGA), while SHF at HH stage 12 persistent truncus arteriosus (PTA). Our results indicated that the abnormal development of certain AHF/SHF at certain stages causes specific spectrum of conotruncal heart defects.