Receiver Operator Characteristic (ROC) Analysis of Lipids, Proteins, DNA Oxidative Damage, and Antioxidant Defense in Plasma and Erythrocytes of Young Reproductive-Age Men with Early Stages of Type 1 Diabetes Mellitus (T1DM) Nephropathy in the Irkutsk Region, Russia

Oxidative stress plays a leading role in the pathogenesis of diabetic nephropathy. However, many aspects of oxidative stress reactions in the initial stages of this disease are not fully understood. The men cohort is of particular interest because of the severe effects of diabetes on their urogenital system. The aim of this study is to assess the intensity of lipids, proteins, DNA oxidative damage, blood antioxidant defense enzymatic, and activity of non-enzymatic components in men with type 1 diabetes mellitus (T1DM) in the early stages of diabetic nephropathy using receiver operator characteristic (ROC) analysis. This study included eighty-nine reproductive-age men in the initial stages of diabetic nephropathy (DN) and thirty-nine age- and sex-matched individuals not suffering from glycemic disorders. The DN patients were divided into two subgroups: stage 1 patients (urinary albumin < 30 mg/day and albumin/creatinine ratio < 3 mg/mmol (n = 45)) and stage 2 patients (urinary albumin 30−300 mg/day and albumin/creatinine ratio 3−30 mg/mmol (n = 44)). Levels of oxidative damage products (conjugated dienes (CDs), thiobarbituric acid reactants (TBARs), methylglyoxal (MGO), and 8-hydroxy-2’-deoxyguanosine (8-OHdG)) and antioxidants (glutathione peroxidase (GPx), glutathione S-transferases π (GSTp), glutathione reductase (GR), copper and zinc-containing superoxide dismutase 1 (SOD-1), total antioxidant status (TAS), α-tocopherol, retinol, reduced glutathione (GSH), and oxidative glutathione (GSSG)) were estimated in plasma and erythrocytes. Oxidative damage to cellular structures (higher values of median CDs (1.68 µmol/L; p = 0.003), MGO (3.38 mg/L; p < 0.001) in the stage 1 group and CDs (2.28 µmol/L; p < 0.0001), MGO (3.52 mg/L; p < 0.001), 8-OHdG (19.44 ng/mL; p = 0.010) in the stage 2 group) and changes in the antioxidant defense system (lower values of TAS (1.14 units; p = 0.011), α-tocopherol (12.17 µmol/L; p = 0.009), GPx (1099 units; p = 0.0003) and elevated levels of retinol (1.35 µmol/L; p < 0.001) in the group with stage 1; lower values of α-tocopherol (12.65 µmol/L; p = 0.033), GPx (1029.7 units; p = 0.0001) and increased levels of GR (292.75 units; p < 0.001), GSH (2.54 mmol/L; p = 0.010), GSSG (2.31 mmol/L; p < 0.0001), and retinol (0.81 µmol/L; p = 0.005) in the stage 2 group) were identified. The ROC analysis established that the following indicators have the highest diagnostic significance for stage 1 diabetic nephropathy: CDs (AUC 0.755; p < 0.