title: Optimisation of an Advanced Oxidation Protein Products Assay: Its Application to Studies of Oxidative Stress in Diabetes Mellitus.
abstract: Advanced oxidation protein products (AOPP) are reportedly elevated in the plasma of patients with a number of diseases, including diabetes mellitus, that involve oxidative stress. However, the accurate measurement of AOPP in human plasma is hampered by the formation of a precipitate following the addition of potassium iodide and glacial acetic acid according to the published assay procedure. Here we describe a modification of the AOPP assay which eliminates interference by precipitation and provides a robust, reliable, and reproducible protocol for the measurement of iodide oxidising capacity in plasma samples (intra-assay CV 1.7-5.3%, interassay CV 5.3-10.5%). The improved method revealed a significant association of AOPP levels with age (p < 0.05) and hypertension (p = 0.01) in EDTA-anticoagulated plasma samples from 52 patients with diabetes and 38 nondiabetic control subjects, suggesting a possible link between plasma oxidising capacity and endothelial and/or vascular dysfunction. There was no significant difference between AOPP concentrations in diabetic (74.8 ± 7.2 μM chloramine T equivalents) and nondiabetic (75.5 ± 7.0 μM chloramine T equivalents) individuals.
authors.affiliation: University of Exeter Medical School and NIHR Exeter Clinical Research Facility, University of Exeter, Exeter EX1 2LU, UK.
authors.forename: Emma L
authors.initials: EL
authors.lastname: Taylor
authors.affiliation: University of Exeter Medical School and NIHR Exeter Clinical Research Facility, University of Exeter, Exeter EX1 2LU, UK.
authors.forename: Kenneth R
authors.initials: KR
authors.lastname: Armstrong
authors.affiliation: Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London EC1M 6BQ, UK.
authors.forename: David
authors.initials: D
authors.lastname: Perrett
authors.affiliation: University of Exeter Medical School and NIHR Exeter Clinical Research Facility, University of Exeter, Exeter EX1 2LU, UK.
authors.forename: Andrew T
authors.initials: AT
authors.lastname: Hattersley
authors.affiliation: University of Exeter Medical School and NIHR Exeter Clinical Research Facility, University of Exeter, Exeter EX1 2LU, UK.
authors.forename: Paul G
authors.initials: PG
authors.lastname: Winyard
mesh_terms: D062107:Advanced Oxidation Protein Products / Q000097:blood*; D000368:Aged; D015415:Biomarkers / Q000097:blood; D016022:Case-Control Studies; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000150:complications / Q000473:pathology*; D005260:Female; D006801:Humans; D006973:Hypertension / Q000150:complications; D008297:Male; D008875:Middle Aged; D018384:Oxidative Stress; D012907:Smoking
chemical_list: D062107:Advanced Oxidation Protein Products; D015415:Biomarkers