HUMAN MACROPHAGE METABOLISM OF LOW-DENSITY-LIPOPROTEIN OXIDIZED BY STIMULATED NEUTROPHILS AND FERRITIN

The metabolism of low density lipoprotein (LDL) oxidized with phorbol myristate acetate (PMA) stimulated neutrophils plus ferritin (LDLox) by human monocyte-derived macrophage (HMDM) was studied. Binding of I-125-labeled LDLox to HMDM and further uptake and degradation were higher than for native I-125-labeled LDL. LDLox seems to be taken up by HMDM through the scavenger receptor as indicated by competition studies with unlabeled native and autoxidized LDL. An increased concentration of cellular cholesteryl esters was observed in HMDM exposed to LDLox. Oxidative modification of LDL increased its electrophoretic migration on agarose gel and also the fragmentation of apolipoprotein B. Data suggest that LDLox is incorporated by human macrophages and can potentially induce foam-cell formation.