Oxidized low density lipoprotein induces ceroid accumulation by murine peritoneal macrophages in vitro.

The presence of ceroid pigment inclusions within macrophage foam cells is a well-recognized phenomenon in human atherosclerosis but its significance is unclear. Murine peritoneal macrophages, maintained in a medium containing 10% lipoprotein-deficient fetal calf serum to which oxidized low density lipoprotein (LDL) has been added, rapidly accumulate similar ceroid inclusions. However, cells exposed to LDL, acetyl--LDL or dextran sulphate--LDL complexes fail to develop ceroid under the same culture conditions. Oxidation of LDL results in considerable physico-chemical changes to both protein and lipid moieties, and these may be important in the uptake of the particles by macrophages and, subsequently, the accumulation of intracellular ceroid.