The intake of olive oil phenolic compounds promotes macrophage-specific reverse cholesterol transport in vivo

Abstract

Background and Aims: In the present study, we determined the effects of the olive oil phenolic compounds on reverse cholesterol transport (RCT) from macrophages to feces in vivo. Methods: [3H]cholesterol-labeled J774 mouse macrophages were injected intraperitoneally into C57BL/6 mice given intragastric doses of refined olive oil (ROO), virgin olive oil enriched with their own phenolic compounds (FVOO, 500ppm), the phenolic compounds (PCs, 500 ppm) resuspended in saline or the saline solution for 14 days and radioactivity was determined in plasma, liver, and feces collected for 48 hours. The amount of preß-HDL was quantified with two-dimensional crossed immunoelectrophoresis. The cholesterol efflux capacity of 3% apoBdepleted plasma samples was determined by using J774 mouse macrophages labeled with TopFluor-cholesterol. RT-PCR assays were performed on a CFX96TM Real-Time System. Results: FVOO caused a significant increase in HDL cholesterol, apoA-I, HDL size and the formation of nascent preb-HDL particles. These changes were concomitant with enhanced macrophage-derived [3H] cholesterol eflux to feces of mice in vivo. PCs intake also promoted macrophage-to-feces RCT compared with that of ROO and vehicle groups. Unlike ROO or vehicle intake, FVOO and PCs intake increased ex vivo macrophage cholesterol efflux, which was closely associated with HDL cholesterol levels. However, the expression of the main liver genes involved in RCT was not affected by FVOO and PCs intake. Conclusions: Consumption of a functional olive oil, enriched with its own PCs, enhances macrophage-specific RCT in vivo. Our data provide direct in vivo evidence of the crucial role of PCs in the induction of macrophagespecific RCT.