July 6, 2010

Model shows how aerobic exercise protects arteries

A new animal model of atherosclerosis, published in the journal Blood on June 15, shows that disturbed blood flow in an artery leads to inflammation followed by clogging of the artery.

The model provides insight into how aerobic exercise protects against atherosclerosis and has allowed the identification of hundreds of genes turned on in atherosclerosis’ initial stages, says biomedical engineer Hanjoong Jo.

Atherosclerosis describes a process where the arterial walls thicken and harden, because of a gradual build-up of white blood cells, lipids and cholesterol. This process can lead to plaque formation, and eventually, heart attacks and strokes. Scientists have previously observed that atherosclerosis tends to occur more in arteries where there are branches and curves, because of the “disturbed flow” branches and curves create.

The standard laboratory model of atherosclerosis has scientists feeding a high-fat diet to mice with mutations in a gene involved in removing fat and cholesterol from the blood. Even then, atherosclerosis usually takes a few months to develop.

“We have developed a model where we disturb blood flow in the carotid artery by partial ligation, and atherosclerosis appears within two weeks,” Jo says. “This rapid progression allows us to demonstrate cause and effect, and to examine the landmark events at the beginning of the process.”

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