Oxidative stress:: potential of distinct peroxide determination systems

When reactive oxygen species attack biological structures, peroxides, which are shortlived oxidative intermediates, are generated. We evaluated the potential of two different, commercially available peroxide activity assays (PoxAct and dROMS) to see whether the results were associated with the clinical condition of subjects who were participating in a routine health care program. Furthermore, we determined the total antioxidant status (TAS) and the titer of autoantibodies against oxidized lowdensity lipoprotein (oLAb) to verify the hydroperoxide measurements. Subjects with medical conditions (hereafter referred to as patients) had significantly increased serum peroxide levels compared to healthy subjects. The dROMS kit indicated that 86% of subjects had an increased level of total peroxides. Although the assays had a significant correlation (p<0.001), 34% of the subjects had an increased total peroxide concentration in the PoxAct assay that was clearly associated with clinical symptoms. Furthermore, the sensitivity of the PoxAct assay was 35 times higher than that of the dROMS kit. In subjects with medical conditions, there was a trend toward a decreased TAS and a slightly increased oLAb titer in comparison to healthy subjects, but this was not statistically significant. The PoxAct assay seems to be a valuable tool for the determination of total peroxides, while the results from the dROMS kit should be considered with caution.