Antioxidant status of children with steroid-sensitive nephrotic syndrome

Eighteen children with steroid-sensitive nephrotic syndrome (SSNS) were stu died. The control group comprised 20 healthy children. The following indire ct parameters of reactive oxygen species activity were determined in nephro tic patients during four stages of the disease (full relapse before prednis one administration, disappearance of proteinuria, prednisone cessation, unm aintained remission): plasma malondialdehyde (MDA) levels, copper/zinc supe roxide dismutase (CuZn SOD) activity and glutathione peroxidase (GPX) activ ity in erythrocytes, reduced glutathione (GSH) and vitamin C levels in whol e blood, and vitamin E level in serum. Increased MDA levels, reduced vitami n C levels, and enhanced CuZn SOD activity were found in relapse. GSH conce ntration was high during all four stages. Vitamin E level was also increase d, parallel to the pattern of serum lipids. GPX activity remained low durin g the proteinuria stage and in remission. We conclude that the majority of abnormal findings can be attributed to the hyperlipidemia of NS. Low GPX ac tivity may be a factor limiting the antioxidant capacity in NS. The present study is inconclusive regarding the role of free radicals in the proteinur ia of NS.