CHAPEL HILL When the arteries delivering oxygen to our vital organs are obstructed by atherosclerosis or clots, the result is almost always a stroke, heart attack or damage to a peripheral tissue such as the legs (peripheral artery disease). But the severity of tissue injury or destruction from a choked-off blood supply varies from person to person, and may depend in large part on whose circulatory system has the best back-up plan to provide alternate routes of circulation.
This "back-up system" called the collateral circulation involves a small number of tiny specialized blood vessels, called collaterals, that can enlarge their diameters enough to carry significant flow and thus bypass a blockage.
Researchers at the University of North Carolina at Chapel Hill School of Medicine have now discovered that the abundance of these vessels in a healthy individual and their growth or remodeling into "natural bypass vessels" depends on how much of a key signaling molecule -- called nitric oxide -- is present.
The study, conducted in animal models, suggests that nitric oxide not only is critical in maintaining the number of collateral vessels while individuals are healthy. It also is key in the amount of collateral vessel remodeling that occurs when obstructive disease strikes.
The research findings recently appeared online in the journal Circulation Research and will be published in the print edition on June 25th. They could one day enable researchers to predict people's risk for catastrophic stroke, myocardial infarction, or peripheral artery disease. Such knowledge could inform individuals with poor collateral capacity to adopt a lifestyle that can help reduce their chances of getting diseases that could further lower their number of collateral vessels.
"If you've got a good number of these natural bypass vessels, you have something of an 'insurance policy' that favors you suffering less severe consequences if you get atheroscle
|Contact: Les Lang|
University of North Carolina School of Medicine