[Mechanisms of gout inflammation]

Abstract

Gout inflammation is an acute and self-resolving reaction. MSU crystals can stimulate cells through either crystal-cell membrane interaction or after their phagocytosis. The onset of gout inflammation relies on non-hematopoietic resident cells whereas the amplification of the reaction is driven by phagocytic cells of immune innate system. Interleukin-1β (IL-1β) and polynuclear neutrophils play central role in gout inflammation. In vitro, MSU crystal-induced IL-1β secretion is secondary mainly to NLRP3 inflammasome activation although numerous proteases are also involved. Mechanisms of NLRP3 inflammasome activation remain unclear involving mostly reactive oxygen species production. Gout resolution involves several mechanisms including monocyte differentiation into macrophage, clearance of apoptotic neutrophils by macrophages, production of Transforming Growth Factor (TGF-β) and modification of protein coating on MSU crystal surface.