title: Onset of cardiac function during early mouse embryogenesis coincides with entry of primitive erythroblasts into the embryo proper.
abstract: When cardiac function and blood flow are first established are fundamental questions in mammalian embryogenesis. The earliest erythroblasts arise in yolk sac blood islands and subsequently enter the embryo proper to initiate circulation. Embryos staged 0 to 30 somites (S) were examined in utero with 40- to 50-MHz ultrasound biomicroscopy (UBM)-Doppler, to determine onset of embryonic heartbeat and blood flow and to characterize basic physiology of the very early mouse embryonic circulation. A heartbeat was first detected at 5 S, and blood vascular flow at 7 S. Heart rate, peak arterial velocity, and velocity-time integral showed progressive increases that indicated a dramatically increasing cardiac output from even the earliest stages. In situ hybridization revealed an onset of the heartbeat coincident with the appearance of yolk sac-derived erythroblasts in the embryo proper at 5 S. Early maturation of the circulation follows a tightly coordinated program.
authors.affiliation: Skirball Institute of Biomolecular Medicine, New York University School of Medicine, New York, NY, USA.
authors.forename: Rui Ping
authors.initials: RP
authors.lastname: Ji
authors.forename: Colin K L
authors.initials: CK
authors.lastname: Phoon
authors.forename: Orlando
authors.initials: O
authors.lastname: Aristizábal
authors.forename: Kathleen E
authors.initials: KE
authors.lastname: McGrath
authors.forename: James
authors.initials: J
authors.lastname: Palis
authors.forename: Daniel H
authors.initials: DH
authors.lastname: Turnbull
mesh_terms: D000818:Animals; D001011:Aorta / Q000196:embryology / Q000502:physiology; D001775:Blood Circulation / Q000502:physiology; D001783:Blood Flow Velocity / Q000502:physiology; D002465:Cell Movement / Q000502:physiology; D004622:Embryo, Mammalian / Q000098:blood supply; D004900:Erythroblasts / Q000166:cytology*; D006321:Heart / Q000196:embryology* / Q000502:physiology*; D006340:Heart Rate, Fetal; D017403:In Situ Hybridization; D051379:Mice; D033401:Microscopy, Acoustic / Q000379:methods; D009206:Myocardium / Q000166:cytology*; D038081:Organogenesis / Q000502:physiology*; D013997:Time Factors; D018608:Ultrasonography, Doppler; D016216:Ultrasonography, Prenatal