Brown and Goldstein's initial experiments showed macrophages would not form foam cells when incubated with LDL, and oxidized seed oils were later demonstrated to be necessary for foam cell formation.

“the gentlemen who discovered the LDL receptor and got a Nobel Prize for it back in the 1980s Brown and Goldstein and the first thing that they tried to do after establishing this pathway existed was take some macro ages and incubate them with LDL and wait for the foam cells to appear and it failed so Steinberg and whitstem to other doctor scientists you know were the guys who finally figured out oh it's the seed oils and they have to be oxidized and then we can make all the foam cells that you want”