Oxidant/antioxidant status and hyperfiltration in young patients with type 1 diabetes mellitus

Diabetic nephropathy (DN), a major cause of morbidity and mortality in diabetes, will develop within a subset of type 1 diabetes mellitus (T1DM) patients, and oxidative stress has been implicated in its pathogenesis. To investigate the relationship between indicators of early DN stages (hyperfiltration estimated by creatinine clearance > or =150 ml/min per 1.73 m(2), microalbuminuria) and oxidative stress, a prospective study was conducted in 29 T1DM patients (age 13.89 +/- 4.61 years) and 18 control subjects (age 13.23 +/- 3.99 years). Blood samples were collected to assay for biomarkers of oxidative stress (malondialdehyde and carbonyl groups) and antioxidants (glutathione peroxidase, reduced glutathione, alpha-tocopherol, and beta-carotene). With respect to control subjects, in T1DM patients, an increase was found in biomarkers of oxidative stress (p < 0.05), mainly due to the group of subjects with hyperfiltration, and a decrease in the ratio alpha-tocopherol/lipids (p < 0.05). In multiple regression analyses, age at disease onset, glycated hemoglobin, microalbuminuria, and oxidative stress biomarkers remained as explicative variables of hyperfiltration (R (2) adjusted = 0.731, p = 0.000). These findings support the importance of the oxidative damage to lipids and proteins, which is linked to hyperfiltration and which could contribute to the development of DN in patients with T1DM.