Growth Factor May Determine Who Grows New Blood Vessels

	August 2, 1999 - The ability of some people to grow new coronary
arteries that re-route blood flow around blockages might be because they
produce a growth factor in their body (a protein that helps grow new
blood vessels). This is from a paper in Circulation: Journal of the
American Heart Association.
	Doctors have long been puzzled by the way some patients form
networks of new blood vessels, called collateral beds, while other
patients do not. A strong collateral blood supply may prevent heart
attacks.
	Israeli researchers found that the ability to grow new vessels
in the heart depends on how much VEGF (vascular endothelial growth
factor) a person produces when the heart muscle is oxygen-starved
(hypoxia).
	The Israeli team studied 51 patients, all having a blockage of
70% or more in at least one coronary artery. All patients had a heart
cath which showed researchers the extent of collateral blood supply in
each patient. The patients were then divided into 3 groups, depending on
the extent of their collateral beds. VEGF levels were also measured.
	There was little difference in the patients' ability to produce
VEGF when cells received normal oxygen levels. However, when the cells
were starved for oxygen, the patients differed in VEGF production.
Those patients who produced the most VEGF during hypoxia had the most
collateral blood supply.
	"We can now work on how to begin making a drug to increase VEGF
production," says the study's author Andrew Levy. The team has developed
a lab test to see if a person produces small or large amounts of VEGF
when heart cells get too little oxygen.
	If more research confirms these findings, doctors could
identify patients unlikely to grow collateral arteries on their own.
Such people would be most likely to benefit from therapy.