Susceptibility of plasma to ferrous iron/hydrogen peroxide-mediated oxidation: Demonstration of a possible Fenton reaction

A. Agil, C. J. Fuller, I. Jialal

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Abstract

The aim of our study was to evaluate a model system by using iron in the peroxidation of plasma. Lipid peroxidation was monitored by fluorometric measurement of lipid peroxides (LPO). Plasma coincubated with Fe2+ and H2O2 had a 268% increase in plasma LPO after 1 h. The optimum concentrations were 0.42 mmol/L Fe2+ and 0.73 mol/L H2O2. Coincubation of plasma with these concentrations of Fe2+ and H2O2 separately resulted in no increase in plasma LPO. The increase in plasma LPO after oxidation with Fe2+/H2O2 was paralleled by a decrease in plasma polyunsaturated fatty acids, an increase in the relative electrophoretic mobility of low-density lipoprotein (LDL), and decreases in apolipoprotein (apo) B-100 and apo A-I immunoreactivity. In vitro oxidation of LDL and high-density lipoprotein separately with this system produced increases of LPO of 246% and 128%, respectively. LPO formation in plasma was inhibited by catalase, desferrioxamine, and mannitol, but not by superoxide dismutase. Hydroxyl radical generation with Fe2+/H2O2 was evidenced by fragmentation of deoxyribose. We conclude that the Fe2+/H2O2 system, possibly by a Fenton reaction mechanism, resulted in significant plasma oxidation. This model system may be useful for examining lipid peroxidation in clinical investigations.

Original languageEnglish (US)
Pages (from-to)220-225
Number of pages6
JournalClinical Chemistry
Volume41
Issue number2
StatePublished - 1995
Externally publishedYes

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ASJC Scopus subject areas

  • Clinical Biochemistry

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