title: Secondary heart field contributes myocardium and smooth muscle to the arterial pole of the developing heart.
abstract: The arterial pole of the heart is the region where the ventricular myocardium continues as the vascular smooth muscle tunics of the aorta and pulmonary trunk. It has been shown that the arterial pole myocardium derives from the secondary heart field and the smooth muscle tunic of the aorta and pulmonary trunk derives from neural crest. However, this neural crest-derived smooth muscle does not extend to the arterial pole myocardium leaving a region at the base of the aorta and pulmonary trunk that is invested by vascular smooth muscle of unknown origin. Using tissue marking and vascular smooth muscle markers, we show that the secondary heart field, in addition to providing myocardium to the cardiac outflow tract, also generates prospective smooth muscle that forms the proximal walls of the aorta and pulmonary trunk. As a result, there are two seams in the arterial pole: first, the myocardial junction with secondary heart field-derived smooth muscle; second, the secondary heart field-derived smooth muscle with the neural crest-derived smooth muscle. Both of these seams are points where aortic dissection frequently occurs in Marfan's and other syndromes.
authors.affiliation: Neonatal-Perinatal Research Institute, Department of Pediatrics (Neonatology), Duke University Medical Center, Bell Building, Room 157, Box 3179, Durham, NC 27710, USA.
authors.forename: Karen L
authors.initials: KL
authors.lastname: Waldo
authors.forename: Mary R
authors.initials: MR
authors.lastname: Hutson
authors.forename: Cary C
authors.initials: CC
authors.lastname: Ward
authors.forename: Marzena
authors.initials: M
authors.lastname: Zdanowicz
authors.forename: Harriett A
authors.initials: HA
authors.lastname: Stadt
authors.forename: Donna
authors.initials: D
authors.lastname: Kumiski
authors.forename: Radwan
authors.initials: R
authors.lastname: Abu-Issa
authors.forename: Margaret L
authors.initials: ML
authors.lastname: Kirby
mesh_terms: D000818:Animals; D001011:Aorta / Q000033:anatomy & histology / Q000196:embryology; D015415:Biomarkers; D002642:Chick Embryo; D002678:Chimera; D006321:Heart / Q000033:anatomy & histology* / Q000196:embryology*; D006801:Humans; D017403:In Situ Hybridization; D009024:Morphogenesis; D009131:Muscle, Smooth, Vascular / Q000166:cytology* / Q000378:metabolism; D009206:Myocardium / Q000166:cytology* / Q000378:metabolism; D009219:Myosin-Light-Chain Kinase / Q000378:metabolism; D009432:Neural Crest / Q000166:cytology / Q000378:metabolism; D011784:Quail
chemical_list: D015415:Biomarkers; D009219:Myosin-Light-Chain Kinase