Evolution of Oxidative Stress in Renal Failure Patients Undergoing Hemodialysis: Progressive Impairment of Antioxidant Defenses

Abstract

Background : Hemodialysis, an essential renal replacement therapy for patients with end-stage renal disease, is known to induce a marked redox imbalance that contributes to the cardiovascular and metabolic burden in this population. Methods : This study assessed the evolution of major oxidative stress biomarkers, malondialdehyde (MDA), reduced glutathione (GSH), total antioxidant capacity (FRAP), and catalase (CAT), in hemodialysis patients in Togo stratified by dialysis vintage (< 1 year, [1 – 2 years[, [2 – 3 years, [3 – 4 years[, [4 – 5 years[, and ≥ 5 years). Findings: A progressive and statistically significant increase in MDA concentrations (from 2.10 ± 0.18 to 3.68 ± 0.33 µmol/L) was observed, concomitant with a continuous decline in GSH (8.7 ± 0.6 to 5.4 ± 0.3 µmol/g Hb), FRAP (690 ± 35 to 470 ± 25 µmol/L), and CAT activity (55.2 ± 2.8 to 38.2 ± 1.9 U/mg protein) as treatment duration increased. Conclusion : These trends reflect an intensification of oxidative stress and a gradual depletion of antioxidant defenses, indicating a cumulative oxidative load associated with repeated dialysis sessions and the loss of water-soluble antioxidants. From a pathophysiological perspective, these alterations may be explained by increased production of reactive oxygen species (ROS), oxidative carbamylation of proteins, chronic inflammation, and the limited biocompatibility of certain dialysis membranes. The resulting chronic oxidative stress plays a pivotal role in endothelial dysfunction and cardiovascular complications among long-term dialysis patients. These findings highlight the need for regular monitoring of redox biomarkers and the implementation of tailored nutritional or pharmacological antioxidant strategies to improve prognosis and quality of life in patients undergoing prolonged hemodialysis.