Lipoprotein distribution of a novel endotoxin antagonist, E5531, in plasma from human subjects with various lipid levels.

The purpose of this study was to determine the distribution profile of a novel endotoxin antagonist, [(14)C]E5531, at 1 microg/ml in plasma samples obtained from fasted human subjects with various lipid and protein concentrations. Our findings suggest that the majority of E5531 binds with high-density lipoproteins (HDLs) independently of plasma lipid and protein levels tested. Furthermore, it appears that an increase in triglyceride-rich lipoprotein (TRL) lipid and protein levels and an increase in low-density lipoprotein (LDL) lipid levels significantly increase TRL plus LDL binding of E5531. However, only an increase in HDL protein levels significantly increases HDL binding of E5531.