RESUMEN
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 non-frequent 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.