Figure 2: Cholesterol efflux capacity of MPO-HDL in fibroblasts and TP1 cells. HDL and MPO-HDL are used as cholesterol acceptors. Cholesterol efflux potential is measured in fibroblasts (white bars) and THP1 cells (black bars) under cholesterol-loaded conditions as described. The cells are labelled for 24 h, with 3H-cholesterol in the absence (a) or presence (b) of LXR agonist. Efflux to HDL (10 μg /mL apoA-I) is measured during a 4 h time span. Efflux medium without HDL is used as a negative control. Fractional cholesterol efflux is determined by measuring the release of radio-labeled cholesterol into the medium. The percentage efflux equals the counts in medium divided by total counts in medium and cells combined, subtracted by efflux to the control. Data are presented as mean ± SD; . Experiments were performed in triplicate.