Evaluation of certain constituents of antioxidant defense in youth treated in the past for steroid-sensitive idiopathic nephrotic syndrome

Disorders of lipid metabolism and antioxidant defense capacity reported during idiopathic nephrotic syndrome (INS) exacerbations are known. The aim of this study was to evaluate constituents of antioxidant defense [ total antioxidant potential: ferric-reducing antioxidant power (FRAP), paraoxonase-1 (PON-1), tocopherols, ascorbic acid] in patients formerly treated for INS. The studied group consisted of 30 patients (20 males and 10 females) treated 415 years ago for INS. The control group consisted of 30 healthy teenagers. There were no statistically significant differences in PON-1 activity (156.4 +/- 97.1 vs 137.7 +/- 80.2 U/l), alpha-tocopherol levels (23.9 +/- 7.3 vs 22.4 +/- 3.2 mu mol/l) and sum of beta- and gamma-tocopherols (2.1 +/- 1.0 vs 2.3 +/- 0.6 mu mol/l), and in FRAP (484.9 +/- 87.2 vs 452.8 +/- 76.9 mu mol/l) between groups. In the study group, a significantly lower concentration of ascorbic acid (53.0 +/- 20.8 vs 69.4 +/- 16 mu mol/l; p<0.002), decreased values of alpha-tocopherol/cholesterol (4.9 +/- 0.7 vs 5.5 +/- 1.2; p=0.03), and total tocopherol/cholesterol (5.3 +/- 0.8 vs 6.1 +/- 1.4; p=0.016) ratios were observed. A positive correlation between tocopherol/total cholesterol (TCh) (r=0.41; p<0.05) and alpha-tocopherol/TCh (r=0.50; p<0.001) ratios and INS relapse frequency was reported. The relationship between the study parameters and group of variables (relapse frequency, duration of the last remission, age, gender) was tested using the multiple linear regression analysis. The results of this study suggest that the nonenzymatic antioxidant defense in young persons formerly treated for INS is weaker than in their healthy counterparts.