[Recent advances in the pathophysiology of hyperuricemia and gout]

Gout is due to the formation and tissue deposition of MSU crystals. Hyperuricemia promotes crystal formation and results from the disequilibrium between the synthetic and elimination rates of uric acid. Recent studies have elucidated the mechanisms of renal handling of uric acid by specific transporters (URATI and OAT) which play a role in uric acid excretion. MSU crystals provoke inflammation by activating leukocytes to produce inflammatory cytokines. One mechanism is through the TLR2 and TLR4 receptors, which form part of the innate immune system. MSU crystals can also activate a protein complex called the inflammasome, which in turn activates IL-1 processing to yield the secreted mature form of IL- 1beta. The inflammatory effects of MSU can be blocked by IL-1 inhibitors. These advances could provide new targetted therapeutic approaches to treat hyperuricemia and gout.