Harvard Heart Letter

Atherosclerosis growth process explained

The hallmark of atherosclerosis is the accumulation of fatty plaques inside the arteries. Have you ever wondered why this happens? Researchers at NYU Langone Medical Center have an explanation.

The immune system orders cells called macrophages to clean up fat and cholesterol. When macrophages fill up with unhealthy cholesterol, they secrete a protein called netrin-1. As the researchers explained in the January 8, 2012, issue of Nature Immunology, this protein signals the macrophages to stop scavenging and stay put. Instead of transporting cholesterol out of the blood vessel, the macrophages settle into the artery walls, where they become part of the fatty plaques. Such plaques are prone to rupture and cause a heart attack.

The researchers were also able to show that removing netrin-1 from the macrophages lowered the amount of plaque that accumulated in the arteries and minimized the growth of atherosclerosis. This finding opens the door for new medications that may prevent or reverse atherosclerosis.

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