Effect of month-long treatment with oral N-acetylcysteine on the oxidative stress and proteinuria in patients with diabetic nephropathy: a pilot study.

Introduction: Oxidative stress plays an important role in the pathogenesis of diabetic nephropathy (DN). This study examined if use of N-acetylcysteine for a month in moderate doses would reduce the oxidative stress in patients with DN and reduce the proteinuria.

Methods: Fifteen volunteers with DN participated in the study. Participants took capsule form of N-acetylcysteine 1 gm twice a day for a month. Spot urines were collected and tested for protein/creatinine on days 1 and 30. Sera were collected on days 1, 15, 30, and 60 and tested for several oxidative stress biomarkers.

Results: There was no significant change in proteinuria or any of the oxidant stress markers at any point: protein-creatinine ratio (day 1, 1.6 +/- 1.8; day 30, 1.3 +/- 1.3), 8-isoprostane (day 1, 5.9 +/- 4.2 pg/mL; day 15, 4.67 +/- 2.4 pg/mL; day 30, 5.1 +/- 2.8 pg/mL; and day 60, 4.7 +/- 1.9 pg/mL), total antioxidant status (day 1, 1.5 +/- 0.1 mM; day 15, 1.6 +/- 0.2 mM; day 30, 1.5 +/- 0.1 mM; and day 60, 1.5 +/- 0.2 mM), aconitase (day 1, 7.9 +/- 5.9 mU/mL; day 15, 10.1 +/- 5.9 mU/mL; day 30, 8.9 +/- 6.2 mU/mL; and day 60, 7.8 +/- 5.5 mU/mL), glutathione peroxidase (day 1, 261.4 +/- 56.4 mU/mL; day 15, 263.9 +/- 57.2 mU/mL; day 30, 269.2 +/- 66.0 mU/mL; and day 60, 257.5 +/- 48.2 mU/mL), and superoxide dismutase (day 1, 242.6 +/- 79.3 mU/mL; day 15, 252.1 +/- 68.1 mU/mL; day 30, 262.0 +/- 73.3 mU/mL; and day 60, 255.7 +/- 61.5).However, 4 patients with initial high isoprostane levels showed nonsignificant decline at each subsequent time point.

Conclusions: N-acetylcysteine in moderate doses given over a month did not have significant effect on the overall oxidative stress in patients with DN and did not reduce proteinuria.