Association between endothelial dysfunction and hyperuricaemia

Objective. We used high-resolution peripheral vascular ultrasound imaging to assess endothelial function in hyperuricaemic patients. Methods. Hyperuricaemia was defined as a serum uric acid concentration of > 7.7 mg/dl in men or > 6.6 mg/dl in women. Measurements of endothelium-dependent flow-mediated vasodilation (FMD) and endothelium-independent nitroglycerin-mediated vasodilation were performed in 46 hyperuricaemic patients and an equal number of healthy age- and gender-matched normal controls by high-resolution two-dimensional ultrasonographic imaging of the brachial artery. The serum levels of glucose, creatinine, alanine aminotransferase (ALT), lipid profiles and high-sensitivity CRP were measured for both the study groups. Results. The serum uric acid levels averaged 9.24 (1.16) and 6.18 (0.99) mg/dl in the hyperuricaemic and control groups, respectively. Body weight and BMI were significantly higher in the hyperuricaemic group than in the control group. The serum levels of creatinine, ALT, triglyceride and high-sensitivity CRP were significantly different between the two groups. The FMD values were significantly lower in the hyperuricaemic patients than in the controls [4.45% (3.13%) vs 7.10% (2.48%); P < 0.001]. The FMD values were negatively associated with serum uric acid levels (r = -0.273; P = 0.009). Multivariate regression analysis showed that the presence of hyperuricaemia (beta = -0.384; P < 0.001) and body weight (beta = 0.215; P = 0.017) were independent determinants of low FMD values. Conclusion. Hyperuricaemia is associated with endothelial dysfunction. Decreased nitric oxide bioavailability may be the main reason.