LOW-DENSITY-LIPOPROTEIN OXIDATION BY STIMULATED NEUTROPHILS AND FERRITIN

Low density lipoprotein (LDL) oxidation mediated by phorbol myristate acetate (PMA)- and formylmethionylleucylphenylalanine (FMLP) -stimulated human neutrophils was enhanced by 70% in the presence of ferritin. Iron released from ferritin by the superoxide anion generated in the respiratory burst of stimulated neutrophils is shown to be involved in lipoprotein oxidation. Ascorbate (100 mum), superoxide dismutase (10 mug/ml) and uric acid (430 muM) showed inhibitory effects of 10%, 70% and 50% on LDL oxidation, respectively. Ceruloplasmin (2.7 muM) potentiated LDL oxidation by stimulated neutrophils and ferritin, both alone and in the presence of methionine. Methionine (1 mM) and catalase (30 mug/ml) increased LDL oxidation by stimulated neutrophils and ferritin. These data suggest that LDL oxidation by stimulated neutrophils and ferritin may be relevant in inflammation when both neutrophils and ferritin are increased.