title: The effect of hemoglobin, hematin, and iron on neutrophil inactivation in superoxide generating systems.
abstract: When Escherichia coli was incubated with xanthine oxidase and acetaldehyde, the killing of E. coli was accelerated by iron-EDTA but inhibited by hematin or hemoglobin. On the other hand, when E. coli was incubated with human neutrophils in the presence of phorbol myristate acetate (PMA), all of these iron species at concentrations of a few micromolar accelerated the inactivation of neutrophils and in so doing protected the E. coli from being killed by the neutrophils. The inactivation of the neutrophils was accompanied by an increase in lipid peroxidation and by a decrease in viability measured with trypan blue. This inactivation was inhibited by scavengers such as deoxyribose, mannitol, or thiourea. Desferrioxamine B and 5,5-dimethyl-1-pyrroline-1-oxide (DMPO) both inhibited the inactivation mediated by iron-EDTA, but had no effect on the hematin- or hemoglobin-mediated inactivation. Vanadium (vanadyl ion), an effective Fenton reagent, behaved in the same way as iron-EDTA relative to the effects of DMPO on neutrophil inactivation. These results led us to conclude that neutrophils were inactivated during PMA stimulation by OH radicals in the presence of iron-EDTA and by some other oxidizing species when hematin or Hb is present. Ascorbate enhanced the inactivation of neutrophils mediated by these iron species. Catalase was very effective in inhibiting neutrophil inactivation. Superoxide dismutase was not as effective but the combination with catalase was most effective.
authors.affiliation: Department of Chemistry and Biochemistry, Utah State University, Logan 84322-0300.
authors.forename: Y M
authors.initials: YM
authors.lastname: Kim
authors.forename: I
authors.initials: I
authors.lastname: Yamazaki
authors.forename: L H
authors.initials: LH
authors.lastname: Piette
mesh_terms: D000328:Adult; D000818:Animals; D001205:Ascorbic Acid / Q000494:pharmacology; D001770:Blood Bactericidal Activity; D002374:Catalase / Q000494:pharmacology; D002417:Cattle; D003497:Cyclic N-Oxides / Q000494:pharmacology; D004492:Edetic Acid / Q000494:pharmacology*; D004926:Escherichia coli; D005290:Ferric Compounds / Q000494:pharmacology*; D016166:Free Radical Scavengers; D006427:Hemin / Q000494:pharmacology*; D006454:Hemoglobins / Q000494:pharmacology*; D006801:Humans; D006861:Hydrogen Peroxide / Q000378:metabolism; D017665:Hydroxyl Radical / Q000494:pharmacology; D015227:Lipid Peroxidation; D009504:Neutrophils / Q000187:drug effects / Q000502:physiology*; D013481:Superoxides / Q000378:metabolism*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D017392:Thiobarbituric Acid Reactive Substances / Q000378:metabolism
chemical_list: D003497:Cyclic N-Oxides; D005290:Ferric Compounds; D016166:Free Radical Scavengers; D006454:Hemoglobins; D017392:Thiobarbituric Acid Reactive Substances; D013481:Superoxides; D017665:Hydroxyl Radical; C017245:5,5-dimethyl-1-pyrroline-1-oxide; D006427:Hemin; D004492:Edetic Acid; D006861:Hydrogen Peroxide; D002374:Catalase; C019179:Fe(III)-EDTA; D013755:Tetradecanoylphorbol Acetate; D001205:Ascorbic Acid