Coronary Artery disease: Scientists make breakthrough discovery

Last Updated: Mar 25, 2010, 00:00 AM IST

Washington: American scientists have claimed
to have identified the source of cells that develop into
coronary arteries, a discovery that can help millions of
people struggling with heart diseases.

A team of scientists from the Stanford University School
of Medicine, during a study of chick embryos observed that
after more than 11 days of conception, cells from an embryonic
cardiac structure -- sinus venosus that directs blood into
developing heart -- began to migrate across the surface of the

By 14.5 days, the cells had developed into recognisable
coronary arteries.

"This was really surprising," said lead author Kristy
Red-Horse in the report that appeared in journal Nature.

"I thought, as many others did, that these cells
(coronary arteries) would arise from the proepicardium. The
second surprise came when we realised the cells were
de-differentiating from venous cells and becoming arteries."

To confirm the finding, the team cultured developing
hearts from mouse embryos in a dish. They observed that, in
contrast to controls, the chambers of hearts from which the
sinus venosus was removed kept beating but never developed
coronary vessels.

The scientists then used a cell-marking technology to
label individual cells in the developing hearts of mouse
embryos with different colours.

The found that a single cell from the sinus venosus
migrated across the heart and became not only the lining of
the coronary arteries, but also of the veins and capillaries
on the heart.

"This is a beautiful example of natural reprogramming,"
said Mark Krasnow, senior author of the study.

"The heart is somehow telling these venous cells to leave
the sinus venosus and convert into coronary arteries. If we
can identify these molecular signals, we might be able to use
them to construct coronary arteries for bypass surgery, which
could be very important therapeutically," Krasnow said.

The team is now trying to identify these signals and
study how they can change the cells` gene expression patterns
as they undergo this conversion.

The next step will be to see whether they can induce
human cells to undergo a similar transformation.

Krasnow said: "During the past several years, some
scientists have made great progress in understanding how
organs develop. Others have made significant advances in
tissue engineering and regenerative medicine. But the two
groups don`t talk to each other much.

"Now we`re trying to apply what we`ve learned about how a
body builds a vessel or an entire organ to building vessels
and organs in the laboratory," he said.

"If we can learn about how coronary arteries develop
normally, we may be able to take that information and engineer
better coronary bypass grafts, or even learn how to increase
blood flow to the heart muscle without surgery," Krasnow said.

Coronary arteries are the vessels that deliver blood to
nourish the continuously pumping heart muscle.