Hemodynamic factors in the development of the chick embryo heart

Abstract

Blood flow patterns have been outlined in the chick embryo heart. The initial flow pattern adapts to the heart form but soon vascular forces affect cardiogenesis. Spiralling of the blood streams in the sinus venosus appears to lead to an expansion of this chamber. The atrial septum forms between parallel streams and evidence is presented that blood flow contributes to septation. Interatrial flow develops with a fusion of the inflow streams bringing the entire systemic venous return into the right atrium when the left atrium receives a small pulmonary return; the difference in pressures is believed to lead to perforation of the septal wall.The ventricular septum also forms between parallel bloodstreams. Inhibition of the left ventricular outflow, brought about by the application of trypan blue to the embryos, was associated with the production of ventricular septal defects. Higher pressures in the left ventricles, brought about by increased vascular resistance to these chambers, led to the defects as evidenced by left to right flow through the defects. An interpretation of the origin of this common congenital anomaly is thus offered.Hemodynamic factors in cardiogenesis have long been under consideration (cf. Goerttler, '58; Jaffee, '62) and are becoming a more frequent subject of experimental analyses (Goerttler, '58; Jaffee, '62; Rychter, '62). Yet descriptions of blood flow through critical stages in cardiac development, based upon direct observations, are not available. Bremer ('32) described blood flow in the chick embryo heart to 48 hours of incubation in his pioneering study.The present report is based upon observations of blood flow in chick embryo hearts from 43 hours to the sixth day of incubation, a period in which most major cardiac structures are formed. Many of these observations were recorded with motion pictures (Jaffee, '63b). Experimental analysis of hemodynamic factors in cardiac development are in progress and a preliminary report is included. MATERIALS AND METHODSWhite Leghorn eggs were incubated in a forced draft incubator at 38.5"C; embryos were removed with vitelline circulations intact and placed in large flat bottomed depression slides, following Patten and Kramer ('33). Blood flow patterns were observed in over 150 embryos rang-ANAT. REC., 151: 69-76. ing from 43 hours to six days incubation. Motion pictures were taken as previously described (Jaffee, '63a).Small areas of the egg shells were cut out with hack saw blades for the experimental procedures and closed with pieces of cover slips and sealed with paraffin. Electrocautery was carried out successfully in 12 embryos in a region lateral to the embryo at 36 hours. Branches of the vitelline veins were tied off at 72 hours in 24 embryos, utilizing 7-0 silk suture.Trypan blue, dissolved to 0.1% in Locke's solution, was dropped over embryos through the windows in amounts from 0.1 to 0.35 ml. The dye was also applied to the branchial region by means of previously saturated (with trypan blue) blocks of agar. Both procedures follow...

Intracardiac flow patterns in early embryonic life. A reexamination.

“…Bremer and Jaffee based their conclusions from visual analysis of the forward movements of the blood cells (Bremer, 1932;Jaffee, 1962Jaffee, , 1963Jaffee, , 1965Jaffee, , 1966Jaffee, , 1967. In our experience, it is extremely difficult-in fact, virtually impossible-to delineate the entire course of the two streams by this method.…”

“…According to the flow-molding theory, there are two spiral streams in the primary heart rube which mold the primitive cardiac chambers and play a major role in the septation process (Spitzer, 1923;Bremer, 1932;Goerttler, 1955;Barthel, 1960;De Vries et al, 1962;Jaffee, 1962Jaffee, , 1963Jaffee, , 1965Jaffee, , 1966Jaffee, , 1967. One stream is the so-called right heart stream which flows selectively through the future right atrium, the right part of the atrioventricular canal, right part of the primitive ventricle, and then spirally through the ventral and left portion of the conotruncus to reach the more caudal branchial arches.…”

“…IT IS a traditional view that spiral streams of blood mold the primary heart tube during its development, and play a major role in the formation of the ventricular, bulbar, and aortico-pulmonary septa (Spitzer, 1923;Bremer, 1932;Goerttler, 1955;Barthel, 1960;De Vries et al, 1962;Jaffee, 1962Jaffee, , 1963Jaffee, , 1965Jaffee, , 1966Jaffee, , 1967. Experiments have been carried out to test this hypothesis.…”

“…Two spiral streams have been described, based on observations of the moving blood cells within the primitive heart (Bremer, 1932;Jaffee, 1962Jaffee, , 1963Jaffee, , 1965Jaffee, , 1966Jaffee, , 1967. This method of evaluation, however, is inadequate for tracing the entire course of the streams in the heart tube, and is subject to error.…”

Developmental Hemodynamic Changes in Rat Embryos at 11 to 15 Days of Gestation: Normal Data of Blood Pressure and the Effect of Caffeine Compared to Data from Chick Embryo

“…Herein we indicate that measurement of blood pressure in the rat embryo is feasible, but with some limitations, and that there may be qualitative hemodynamic differences between the rat and chick embryos. (Pediatr Res 23: 200-205,1988) While searching for the basic mechanism of normal and abnormal morphogenesis of the cardiovascular system, several investigators have been trying to correlate the change of hemodynamics or rheology of the cardiovascular system to morphogenesis (1)(2)(3)(4)(5). These studies have revealed that several teratogenic factors alter the hemodynamics (6-12).…”