As summarized in this Figure, there are different functional ways to efflux cholesterol out of the macrophage cells in arterial plaques: passive diffusion, ABCA1 mediated efflux, ABCG1 mediated efflux, and SRB1 bidirectional cholesterol efflux. Work done by Dan Rader’s group, presented elsewhere in this publication, has shown the correlation between the ability of the HDL particles of different subjects with CVD/CHD to efflux cholesterol via these mechanisms, and the presence or absence of disease. As shown in this Figure, however, this means looking at 4 different processes, with the large alpha1 HDL particles interacting with the SRB1 transport receptor and the very small alpha3,4 particles interacting with ABC1A transporter.
J Clin Lipidol. 2011; 5(6).