How cholesterol clogs the arteries

A high-cholesterol diet can be the fast track to a heart attack. But scientists are only now discovering that one of cholesterol's most damaging effects might stem from its ability to make blood cells self-destruct. The findings appear in a pair of recent studies directed by Ira Tabas (Columbia University, New York, NY).

Cholesterol is abundant in atherosclerotic lesions, which become most dangerous when they break apart and plug an arterial passage. Unstable lesions are associated with lots of cellular debris, mostly from dead macrophages. Tabas, along with Bo Feng and colleagues, shows in one article that macrophages die in lesions because cholesterol elicits the unfolded protein response (UPR) in the ER.

Macrophages that were unable to deal with the excess cholesterol they ingested had depleted ER calcium stores and...