Lack of correlation between in vitro and in vivo effects of low density lipoprotein on the inflammatory activity of monosodium urate crystals.

The effect of coating monosodium urate crystals (MSU) with low density lipoprotein (LDL), postulated previously as a major regulator of gouty inflammation, was studied in a neutrophil chemiluminescence (CL) assay and an air pouch model of inflammation induced by MSU. LDL crystalline coating abrogated the neutrophil CL response but, in contrast, had no inhibitory effect on leucocyte accumulation, levels of the prostaglandin (PG) metabolite 6-keto-PGF1 alpha, and exudation of plasma proteins in the in vivo model. This latter observation raises doubts about the postulated physiological role of LDL in terminating the acute gouty attack.