Uric acid and hypertension.

Increased levels of uric acid are associated with cardiovascular disease and the metabolic syndrome. They may predict clinical outcomes and also the onset of hypertension, though it is less clear that hyperuricaemia can be regarded as an independent risk factor given its clustering with other well-recognised factors. Uric acid may increase as a result of pathophysiological processes such as impaired renal sodium handling but may also contribute to renal and vascular damage, particularly endothelial dysfunction. It is notable that the synthesis of uric acid may be associated with the generation of reactive oxygen species if the enzyme xanthine oxidorectase is converted to the oxidase, as may occur in ischaemia. It has been suggested that uric acid may play a role in the pathogenesis of early-onset hypertension but evidence for this is limited. There is also very limited data to suggest that in some circumstances lowering uric acid can lower blood pressure. In the metabolic syndrome, the presence of elevated uric acid concentrations is closely associated with raised triglyceride levels, for reasons that have not been clearly defined. It remains to be seen whether uric acid could or should be considered a specific therapeutic target in cardiovascular disease and especially in hypertension and if so what should be the optimal pharmacological approach to lowering serum urate levels.