Figure 6. Quantifying the ability of apolipoprotein A (LPA) and lipoprotein(s) to promote cholesterol efflux and to inhibit plasminogen-mediated cholesterol efflux from ABCA1-expressing BHK cells.

Cholesterol efflux was quantified using [³H]cholesterol-labeled BHK cells incubated for 4 hours with the indicated concentrations of lipoprotein(a) [Lp(a)], LPA, or APOA1. Lp(a) was isolated by ultracentrifugation, size-exclusion chromatography, and L-proline affinity chromatography from plasma of a subject with high plasma levels of Lp(a). LPA was isolated from the medium of HEK293 cells expressing human recombinant LPA with 17 kringle domains and purified by L-lysine Sepharose affinity chromatography. CEC, cholesterol efflux capacity; PLG, plasminogen.