Developmental hemodynamic changes in the chick embryo from stage 18 to 27.

Abstract

SUMMARY. We report the hemodynamic parameters of stage 18, 21, 24, and 27 chick embryos (from 3 to 5 days of incubation). Dorsal aortic blood velocity and mean vitelline artery blood pressure are measured with a 20 MHz pulsed-Doppler meter and servo-null pressure system respectively. We also measure heart rate, dorsal aortic diameter and embryo weight of each developmental stage. From these data, we calculate mean dorsal aortic blood flow, mean dorsal aortic blood flow per cardiac cycle, mean dorsal aortic blood flow per milligram embryo weight, vascular resistance and cardiac work. Blood flow increases geometrically with each embryo stage but remains constant when normalized for embryo weight. Mean arterial pressure increases linearly and vascular resistance decreases geometrically. Cardiac work increases in proportion to embryo weight. These results define the parameters of normal hemodynamic function during early embryonic development. (Ore Res 51: 810-815, 1982) BLOOD FLOW in the embryo begins soon after the tubular heart starts to pulsate and continues during subsequent morphogenesis of the cardiovascular system. Since form and function are interrelated, it is important to understand the contribution of each in cardiac development. Structural changes during formation of the heart have been studied extensively (DeHaan 1965). Analysis of experimental studies in cardiac development leads many investigators to hypothesize that functional alteration is a mechanism for morphological abnormality (Rychter, 1962;Jaffee, 1970;Rosenquist and Bergsma, 1979;Pexieder, 1981). Little information is available on the hemodynamic changes during organogenesis. VanMierop and Bertuch (1971) and Girard (1973) measured heart rate and blood pressure in the chick embryo. Faber et al. (1974) reported cine-photographic estimated stroke volume and heart rate in the chick embryo. However, there is no integrated description of the hemodynamic characteristics during embryonic development in bird or mammal.The chick embryo is a useful model for the study of hemodynamic changes during early development because avian and mammalian hearts are similar at the early stages and access to the embryo is relatively easy. It is only with the completion of organ development that the morphological differences between the avian and the mammalian heart are apparent. Birds have a muscular tricuspid valve, right aortic arch, and bilateral ductus arteriosus. In this paper, we describe a method for measuring blood pressure and dorsal aortic velocity and report the normal hemodynamic parameters in the chick embryo from the third to the fifth day of incubation. This manuscript from the University of Iowa was sent to Brian M. Hoffman, Consulting Editor, for review by expert referees, for editorial decision, and final disposition. MethodsFertile White Leghorn chicken eggs were incubated blunt end up in a forced-draft constant humidity incubator to Hamburger-Hamilton (1951) stage 18 (3 days), 21 (3.5 days), 24 (4 days), and 27 (5 days). We chose those stages ...

Impact of Hypoxia on Early Chick Embryo Growth and Cardiovascular Function

“…We then excised the embryo by severing the vitelline veins and arteries where they exited the embryo and removed all extraembryonic membranes. Embryos were lightly blotted on filter paper and weighed (22). Ventricular pressure.…”

Dependence of Aortic Arch Morphogenesis on Intracardiac Blood Flow in the Left Atrial Ligated Chick Embryo

“…10 in each parameter) with a 20-MHz ultrasound pulsed-Doppler flow meter (Clark and Hu, 1982;Hu and Clark, 1989). Dorsal aortic blood velocity was measured with a 750-lm diameter piezoelectric crystal positioned over the dorsal aorta adjacent to the sinus venosus.…”

Elastic extracellular matrix of the embryonic chick heart: An immunohistological study using laser confocal microscopy

“…Gallagher et al, (1993) have previously suggested a mechanical function for fibrillin in the process of gastrulation. The heart, even during the earliest stages of development, undergoes significant mechanical stress (Clark and Hu, 1982) and therefore most probably requires a specialized elastic matrix. Our results indicate that some of the endocardial cells and the cushion tissue mesenchyme derived from these cells account for the production of the first elastic matrix components of the heart.…”

“…The intensity and the pattern of dergoes changes during the course of development. In the chick embryo hemodynamic changes are particularly evident between stages 17 and 27 (Clark and Hu, 1982;Cuneo et al, 1993). Moreover, the septation of the embryonic tubular heart into a four-chambered organ causes extensive redistribution of stress, and structures such as the valve leaflets and pericardium serve a key role in supporting mechanical tension during heart maturation (Tidball, 1992).…”