Preparation of a complex of dexamethasone palmitate-low density lipoprotein and its effect on foam cell formation of murine peritoneal macrophages

In the early progression of atherosclerosis, LDL migrates in the subendothelial space of the artery and plays an important role in foam cell formations of macrophages. LDL may serve as a carrier of site-specific delivery of drugs to atherosclerotic lesions. In this exploratory study, dexamethasone palmitate (DP) was incorporated in LDL, and an inhibitory effect of this complex on foam cell formations was examined. LDL was isolated from human plasma, and the DP-LDL complex was prepared by incubation in the presence of Celite 545. No degradation nor modification of LDL was observed. The DP/LDL molar ratio of the complex was 35-50:1. Foam cell formations of murine macrophages were induced by incubation with oxidized LDL. When macrophages were pretreated with the DP-LDL complex, accumulation of cholesterol ester in the macrophages induced by oxidized LDL, i.e., an index of foam cell formation, was decreased. These findings indicated that the DP-LDL complex showed similar characteristics to LDL, and the DP-LDL complex inhibited foam cell formations of macrophages in vitro. This study provides the basis for further study of the DP-LDL complex as a drug-carrier complex for treatment of atherosclerosis.