Progressive Alterations in Oxidative Stress Biomarkers across Chronic Kidney Disease Stages

Abstract

Chronic kidney disease (CKD) is characterised by progressive redox imbalance, yet it remains unclear which oxidative-stress markers track disease severity rather than merely distinguishing disease from health. In this cross-sectional study, five oxidative-stress and antioxidant biomarkers — coenzyme Q10 (CoQ10), F2-isoprostane, advanced glycation end-products (AGEs), 8-hydroxy-2’-deoxyguanosine (8-OHdG) and glutathione peroxidase (GPx) — were measured in 60 male controls and 120 male patients with CKD stratified into five stages (n = 24 per stage; total N = 180). Groups were compared by Kruskal–Wallis and Bonferroni-corrected Mann–Whitney U tests, diagnostic performance by receiver operating characteristic (ROC) analysis, and associations by Spearman correlation. All five biomarkers differed significantly across groups (p < 0.001). CoQ10 declined progressively from control to Stage 5 (7.26 ± 2.16 to 2.29 ± 0.19 ng/mL), while F2-isoprostane, AGEs and 8-OHdG rose progressively (all ε² ≥ 0.90). These four markers correlated strongly with estimated glomerular filtration rate (eGFR) and creatinine (|ρ| ≥ 0.90) and discriminated CKD from control well (AUC 0.82–1.00). GPx was markedly higher in every CKD stage than in control (p < 0.001) but did not differentiate the stages (Stage 1 vs Stage 5, p = 0.847) and was uncorrelated with eGFR within the CKD group (ρ = −0.13, p = 0.150), indicating an early, saturating rather than severity-tracking response. CoQ10, F2-isoprostane, AGEs and 8-OHdG therefore track CKD severity in a graded, diagnostically useful manner, whereas GPx elevation appears to be an early threshold response to renal impairment rather than a marker of progression.