Abstract / Summary
Background: Ferroptosis is an iron-dependent form of regulated cell death characterized by excessive lipid peroxidation and impaired antioxidant defense. Increasing evidence implicates ferroptosis in diabetic kidney injury, but its relationship with early diabetic nephropathy (DN) and albuminuria remains incompletely defined. Aims: This study investigated ferroptosis-related biomarkers, the glutathione peroxidase-4 (GPX4) antioxidant axis, iron homeostasis, and oxidative–antioxidant balance in healthy controls (HCs), patients with type 2 diabetes mellitus (T2DM) without nephropathy, and patients with T2DM and early DN, while examining their relationships with age, sex, diabetes duration, and body mass index (BMI). Methods: Ninety participants were equally allocated to three groups (n = 30 each): HCs, patients with T2DM without nephropathy, and patients with T2DM and early DN. Renal status was evaluated using serum urea and creatinine, estimated glomerular filtration rate (eGFR), and urinary albumin-to-creatinine ratio (ACR). Malondialdehyde (MDA), reduced glutathione (GSH), total antioxidant capacity (TAC), superoxide dismutase (SOD), catalase, and nitric oxide (NO) were measured using colorimetric assays, whereas GPX4 was quantified by enzyme-linked immunosorbent assay (ELISA). Results: Patients with early DN exhibited significantly higher MDA, serum iron, ferritin, transferrin saturation, and NO, accompanied by lower GSH, GPX4, TAC, SOD, and catalase than HCs and patients with T2DM without nephropathy (all p < 0.001). Urea, creatinine, and ACR were increased, whereas eGFR was decreased (p < 0.001). Receiver operating characteristic (ROC) analysis showed strong discriminatory performance for MDA (area under the curve [AUC] = 0.936, 95% confidence interval [CI]: 0.884–0.988; cut-off >3.92 nmol/mL; sensitivity, 90.0%; specificity, 88.3%) and GPX4 (AUC = 0.921, 95% CI: 0.864–0.978; cut-off ≤5.18 ng/mL; sensitivity, 88.3%; specificity, 86.7%). Conclusion: Early DN was associated with a biochemical profile characterized by increased lipid peroxidation and iron availability alongside impaired GPX4-dependent and broader antioxidant defenses, consistent with enhanced ferroptosis-related oxidative stress. MDA and GPX4 showed promising discriminatory performance for early DN in this study population and warrant validation as candidate biomarkers in larger prospective cohorts.