There are thousands of babies born with congenital heart defects each year. And while these defects are responsible for more deaths in the first year of life than any other congenital problem, what leads to the formation of abnormal hearts is poorly understood.
Now, researchers at UC and Duke University have found a way to measure blood flow and structure imaging of the heart within a chicken embryo, which develops similarly to a human embryo’s heart. By studying embryonic heart development in chickens, researchers can better understand and develop treatments for congenital heart disease in humans.
“There are essentially no good ways of directly observing a young embryo’s heart,” says Florence Rothenberg, MD, assistant professor in the cardiovascular diseases division at UC.
“In the earliest stages of the heart’s development, the organ is so small that there is no way to accurately image it in high resolution without harming the embryo.”
Rothenberg, co-author of this study, and colleagues at Duke combined optical coherence tomography with spectral Doppler velocimetry to provide some of the first insights into the mechanism of blood flow at the earliest stages of heart development—when the heart first begins to beat.
“Optical coherence tomography, or OCT, was actually first used in imaging the human retina,” Rothenberg says, adding that it can also be used in imaging the esophagus and the coronary arteries to look for disease.
OCT allows extremely highquality, three-dimensional images in biological tissue to be obtained. “This allows us to view a highresolution image without artifacts due to motion from the constantly beating heart, and we don’t have to destroy the chicken embryo, allowing us to image it multiple times as it develops,” she says.
“We are able to image the heart in its entirety—non-invasively—before it even starts beating.”
Doppler velocimetry images blood flow in living human hearts, measuring change in movement of the red blood cells over time.
“The advantage to optical coherence tomography, a technique that relies on properties of light waves, over standard echocardiography, which involves sound waves, is that it can image particles as close as 10 microns apart—significantly higher resolution than standard ultrasound techniques,” Rothenberg says.
Understanding how congenital heart defects develop would be a huge step in creating cardiovascular disease treatments, she adds.
“Earlier interventions for people born with heart defects save lives and improve quality of life,” she says. “Our next step is to see how we can image embryos that hide inside a uterus, like the human and the mouse.
“These techniques are being developed by collaborators at Case Western Reserve University.
“We hope this research will one day help us create early therapies to eliminate or minimize these problems,” says Rothenberg.