Effects of reagent and cell-generated hydrogen peroxide on the properties of low density lipoprotein Academic Article uri icon

Overview

MeSH Major

  • Hydrogen Peroxide
  • Lipoproteins, LDL

abstract

  • Low density lipoprotein (LDL) isolated from human plasma anticoagulated with EDTA (EDTA/LDL) was 4-fold more resistant to oxidation by reagent H2O2, as assayed by the thiobarbituric acid (TBA) assay, than LDL prepared from plasma anticoagulated with citrate (CDP/LDL). The LDLs required 1-3 mM H2O2 for maximal oxidation by this assay, and ED50S were 1.7 X 10(-3) M for EDTA/LDL and 4.5 X 10(-4) M for CDP/LDL. Oxidation was enhanced 2.3-fold by Cu2+ ions. Rabbit endothelial cell line monolayers released two orders of magnitude less H2O2 than was required to oxidize LDL and failed to induce TBA reactivity in either EDTA/LDL or CDP/LDL after a 24-hr coincubation. However, this LDL was subsequently degraded by mouse macrophages more rapidly than untreated LDL. Freshly isolated human monocytes (2 X 10(6) cells per ml), with or without phorbol myristate acetate (100 ng/ml) to trigger the respiratory burst, did not oxidize LDL in the TBA assay, despite producing large amounts of reactive oxygen intermediates. EDTA/LDL, CDP/LDL, and acetoacetylated LDL failed to trigger H2O2 release from human monocytes or macrophages. These results separate oxidation of LDL as measured by TBA assay from the modification of LDL by rabbit aortic endothelial cell line that leads to its subsequent enhanced degradation by macrophages.

publication date

  • December 1986

Research

keywords

  • Academic Article

Identity

Language

  • eng

PubMed Central ID

  • PMC386558

PubMed ID

  • 3018740

Additional Document Info

start page

  • 6631

end page

  • 5

volume

  • 83

number

  • 17