Serum uric acid levels correlate with plasma hydrogen peroxide and protein carbonyl levels in preeclampsia

Background: Increased serum uric acid has been postulated to directly promote oxidative stress. The aim of this study was to investigate whether serum uric acid level correlated with superoxide generation and oxidative stress in preeclampsia. Methods: We assessed serum uric acid levels, plasma hydrogen peroxide levels, and plasma protein carbonyl levels in normal pregnant (n = 14) and preeclamptic women (n = 17). Serum uric acid and plasma hydrogen peroxide levels were determined by the uricase-peroxidase method, a combined enzymatic-colorimetric method. Plasma carbonyl levels were measured by ELISA. Results: The mean serum uric acid values were significantly elevated in preeclampsia (6.6 ± 1.5 mg/dl) compared with normal pregnancy (4.0 ± 0.7 mg/dl) (P < 0.001). Plasma protein carbonyl levels were also significantly elevated in preeclampsia (7.72 ± 4.10 nmol/mg) compared with normal pregnancy (2.85 ± 3.06 nmol/mg) (P = 0.0011). In addition, the plasma hydrogen peroxide levels were significantly higher in preeclampsia (66.9 ± 10.9 μmol/l) compared with normal pregnancy (50.1 ± 5.6 μmol/l) (P < 0.001). Serum uric acid levels correlated significantly and positively with plasma hydrogen peroxide levels (r² = 0.2965, P = 0.0027) and plasma protein carbonyl levels (r² = 0.2011, P = 0.0129). Conclusion: The increased serum uric acid levels correlated closely with plasma hydrogen peroxide levels and plasma protein carbonyl levels in preeclampsia. Therefore, the serum uric acid level serves as an indicator of the underlying oxidative stress in preeclampsia.