Asymptomatic hyperuricaemia: a silent activator of the innate immune system

Asymptomatic hyperuricaemia precedes and potentially contributes to the development of gout and other chronic diseases. This review summarizes what is known about the effects of uric acid on pro-inflammatory responses. Asymptomatic hyperuricaemia affects ~20% of the general population in the USA, with variable rates in other countries. Historically, asymptomatic hyperuricaemia was considered a benign laboratory finding with little clinical importance in the absence of gout or kidney stones. Yet, increasing evidence suggests that asymptomatic hyperuricaemia can predict the development of hypertension, obesity, diabetes mellitus and chronic kidney disease and might contribute to disease by stimulating inflammation. Although urate has been classically viewed as an antioxidant with beneficial effects, new data suggest that both crystalline and soluble urate activate various pro-inflammatory pathways. This Review summarizes what is known about the role of urate in the inflammatory response. Further research is needed to define the role of asymptomatic hyperuricaemia in these pro-inflammatory pathways.