HDL particles are thought to extract excess cholesterol from tissues, including artery cells, to prevent toxicity and plaque formation.

“Well, certainly, one of the reasons that's true is thought to be the process you've just described, which is the ability of HDL, and particular forms of HDL which are still being studied, to extract cholesterol from tissues. All tissues, as I say, make cholesterol, and when there's excess cholesterol in the cell, it can be toxic to the cell. So it's an important role for HDL to scavenge cholesterol or to extract it from these tissues that are making cholesterol. And one of those tissues is the artery, and there are cells in the artery, macrophages, that are filling up with cholesterol that could ultimately cause heart attacks, you know, through plaque formation.”