Oxidative stress and homocysteine metabolism in patients with lupus nephritis

The objective of this study was to compare oxidative status and homocysteinemia in patients with lupus nephritis (LN) and in controls. Total antioxidant capacity (TAC), reactive oxygen species (ROS), homocysteine and related vitamins were measured in 68 patients with LN and in 50 controls. LN patients had lower TAC (p = 0.05) and higher ROS and homocysteinemia (p = 0.01) than controls. TAC, significantly lower in active than in quiescent LN (p = 0.01), was correlated with albuminemia (p = 0.02), inversely with proteinuria (p = 0.01) and anti-DNA antibodies (p = 0.004). ROS values, higher both in active and in inactive LN, correlated with age (p = 0.02), C-reactive protein (CRP) (p = 0.0005) and inversely with prednisone dosage (p = 0.05). At multivariate analysis, CRP (p = 0.04) and age (p = 0.005) were independent ROS predictors. Homocysteine, higher in active than in quiescent LN (p = 0.016) and in patients with antiphospholipid antibodies (p=0.05), correlated with serum creatinine (p = 0.00001) and proteinuria (p = 0.015). At multivariate analysis serum creatinine (p = 0.006) and active nephritis (p = 0.003) were independent predictors of hyperhomocysteinemia. Patients with LN showed impaired oxidative status, even without clinical signs of renal activity. ROS production may be counterbalanced by adequate antioxidant capacity in some patients with quiescent LN. The association of hyperhomocysteinemia and antiphospholipid antibodies positivity may increase the risk of cardiovascular and/or thrombotic events in LN patients.