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) b y human monocyte-derived macrophage (HMDM) was studied. Binding of I-1 25-labeled LDLox to HMDM and further uptake and degradation were highe r than for native I-125-labeled LDL. LDLox seems to be taken up by HMD M through the scavenger receptor as indicated by competition studies w ith unlabeled native and autoxidized LDL. An increased concentration o f cellular cholesteryl esters was observed in HMDM exposed to LDLox. O xidative modification of LDL increased its electrophoretic migration o n agarose gel and also the fragmentation of apolipoprotein B. Data sug gest that LDLox is incorporated by human macrophages and can potential ly induce foam-cell formation.