Cholesterol absorption from the intestine is a major determinant of reverse cholesterol transport from peripheral tissue macrophages

Abstract

Objective: We examined the effect of ezetimibe, a cholesterol absorption (CA) inhibitor, and genetic determinants of CA on reverse cholesterol transport (RCT) from subcutaneously injected macrophages using a new dual isotope label technique.

Methods and results: Treatment of C57BL/6J mice with ezetimibe decreased dietary CA by 86% and increased RCT from peripheral tissue macrophages (PTM) by 6-fold (P<0.0001). Moreover, congenic 14DKK mice with a modest 41% decrease in dietary CA displayed a 67% increase in RCT from PTM (P<0.007).

Conclusions: These findings indicate that pharmacological and genetic modifiers of cholesterol absorption are major determinants of reverse cholesterol transport from peripheral tissue macrophages.

Figure 1. Time course of fecal [¹⁴C]-cholesterol and [³H]-β-sitostanol labels excretion from subcutaneously injected macrophages

[¹⁴C]-cholesterol and [³H]-β-sitostanol labeled RAW 264.7 macrophages were injected subcutaneously into C57BL/6J females, and the percent of injected [¹⁴C]-cholesterol and [³H]-β-sitostanol labels excreted into feces was determined (N=5 animals).

Figure 2. Ezetimibe treatment and congenic 14DKK interval increase the fecal excretion of cholesterol from peripheral tissue macrophages

(A) C57BL/6J females were chow fed with or without 0.005% ezetimibe, injected subcutaneously with duel-labeled macrophages, feces were collected for 48h and percent fecal excretion of injected macrophages cholesterol was calculated. Line corresponds to mean value. (B) Chow fed C57BL/6J controls and 14DKK congenics were injected with labeled macrophages and feces processed for analysis as described in the legend for Figure 2A.