One of the standard laboratory methods for studying the early stages of heart development is to use microsurgery to remove a chick heart from an embryo and place it in a cell-culture dish filled with collagen gel. However, the method was not suitable for studying mechanical forces so Sewell-Loftin had to modify it substantially. She found one key was to include a complex sugar called hyaluronic acid, which is found in cardiac jelly.
Next, she had to devise a method to measure the amount of deformation that the pulsation of the heart muscle cells causes in the gel. She did so by creating a computer program that analyzed sequences of microscope images of the gel surface to estimate the forces caused by the pulsing cells.
When Sewell-Loftin compared her maps with the locations where VICs were being formed, she found that cells were transforming preferentially in areas of high strain.
The team's next step is to collaborate with a researcher who works with induced pluripotent stem cells a type of stem cell that can be generated directly from adult cells to produce endothelial cells. Once they have these cells, they hope to produce human VICs. In addition to guiding the initial formation of the heart, VICs are known to play a role in maintaining valve health in adults. So they could provide a better way to repair calcified heart valves, the major cause of open-heart surgery in adults, the researchers speculate.
Once they can make human VICs, there is a good chance that they will create artificial human heart valves when they are placed in a properly designed bioreactor, the researchers anticipate. And once they have artificial human heart valves, they could be used to replace defective valves when needed in the 40,000 babies born with congenital heart defects each year. Hopefully, these artificial valves would grow with the child. Current replacement valves are made out of plastic so they do not grow with a chil
|Contact: David Salisbury|