Plasma levels of oxidative stress in children with steroid-sensitive nephrotic syndrome and their predictive value for relapse frequency

Background Oxidative stress has been reported to play an important role in children with primary nephrotic syndrome (PNS). However, the results of previous studies are controversial. Methods Forty children with steroid-sensitive nephrotic syndrome (SSNS) and 20 age- and sex-matched healthy controls were enrolled. Patients were followed-up for 12-18 months and divided into three subgroups: frequent relapse (n=10), non-frequent relapse (n=12), and non-relapse (n=18). The plasma levels of advanced oxidation protein products (AOPP), malondialdehyde (MDA), and superoxide dismutase (SOD) were tested in controls and patient group at first presentation and after 4 weeks of steroid treatment. Results Patients had higher AOPP and MDA levels but lower SOD compared with controls. AOPP levels were significantly higher in the frequent relapse subgroup compared with the nonfrequent relapse and non-relapse subgroups, respectively. No significant differences were found in the plasma levels of MDA and SOD among the three subgroups. AOPP >87.55 μmol/l before steroid treatment and AOPP >78.5 μmol/l after 4-week steroid treatment were positively correlated with the relapse frequency in patients with SSNS. Conclusions Children with SSNS have oxidative stress. The plasma levels of AOPP before and after 4-week steroid treatment may predict whether patients with SSNS will relapse frequently.