Serum Peroxiredoxins Reflect Oxidative Stress and Predict Renal Outcomes in Patients with Glomerulonephritis

Oxidative stress (OS), defined as an imbalance between pro-oxidant and antioxidant mechanisms, contributes to DNA and protein oxidation as well as cellular injury, and plays a pivotal role in the pathogenesis of chronic kidney disease (CKD). Peroxiredoxins (PRDXs) are key antioxidant enzymes that regulate intracellular peroxide levels and maintain redox homeostasis. Beyond its renal implications, OS is closely intertwined with hypertension and atherosclerosis, both common comorbidities that accelerate CKD progression. As previously reported, serum concentrations of PRDXs 1-5 may help to differentiate between IgA nephropathy (IgAN), membranous nephropathy (MN), and lupus nephritis (LN). This study aimed to assess the utility of baseline serum PRDX levels in predicting longitudinal changes in kidney function and proteinuria in patients with IgAN, MN, and LN. We analyzed data from 80 patients (IgAN, n = 36; MN, n = 23; LN, n = 21) drawn from an initial cohort of 108 in whom baseline serum concentrations of PRDX 1-5 were measured. Patients were stratified into low, medium, and high PRDX level groups at baseline, and associations between these strata and longitudinal changes in eGFR and proteinuria were assessed over a follow-up period of up to five years. Across all groups, the follow-up eGFR was significantly associated with low baseline serum PRDX 1, 2, 3, and 5 (p = 0.043; p = 0.001; p = 0.036; p = 0.007, respectively). Significant associations were also observed between 24 h follow-up proteinuria and low baseline serum PRDX 2, 3, and 5 (p = 0.025; p = 0.025; p = 0.005, respectively), medium PRDX 4 (p = 0.010), and high PRDX 2 (p = 0.019). No significant associations were found within the study groups; however, these associations were more pronounced in IgAN and MN patients. These findings suggest a potential role for PRDXs in predicting and monitoring CKD progression, especially eGFR decline.