Abstract

Increased serum uric acid has been identified as an independent risk factor for cardiovascular disease. However, because of its antioxidant capacity, uric acid may play a beneficial role in endothelial function. This paradoxical relationship between uric acid and endothelial function in chronic heart failure patients remains poorly understood. Thirty-eight chronic heart failure patients (New York Heart Association functional class II-III, mean age 58 ± 10 years and mean left ventricular ejection fraction 25 ± 8%) and twelve age-and-sex-matched healthy controls were studied. Chronic heart failure patients showed higher uric acid levels (7.3 ± 2.3 mg/dL vs. 6.1 ± 0.2 mg/dL, p < 0.05) and lower extracellular superoxide dismutase activity (136 ± 36 U ml- 1 min- 1 vs. 203 ± 61 U ml- 1 min- 1, p < 0.01) and endothelium-dependent vasodilatation (4.0 ± 1.6% v. 9.1 ± 3.0%, p < 0.01) when compared with control subjects. In chronic heart failure patients, correlations between both uric acid levels and extracellular superoxide dismutase activity (r = 0.45; p < 0.01), and uric acid and endothelium-dependent vasodilatation (r = 0.35; p = 0.03) were detected. These correlations were not observed in healthy individuals, suggesting a positive effect of uric acid on endothelial function partially mediated by modulation of extracellular superoxide dismutase activity in chronic heart failure. © 2008 European Society of Cardiology.