The transport of excess cholesterol by high density lipoproteins (HDL) from macrophages in the periphery back to the liver, called reverse cholesterol transport, plays an important protective role in the development of atherosclerosis. Macrophage ATP binding cassette transporter G1 (ABCG1) mediates cholesterol effluence to HDL thus preventing foam cells formation. However, after a number of experiments with transgenic animals it's role in human atherosclerosis development is still undiscovered.
The aim of this study was to investigate the influence of ABCG1 gene expression in macrophages on atherosclerosis development. Human peripheral blood monocytes were obtained from 29 volunteers (60% men and 40% women, mean age 45.9): 15 patients with angiographically proved atherosclerosis of different localization and 14 healthy blood donors. ABCG1 mRNA levels were measured in monocytes derived macrophages using real time PCR and normalized to beta-actin. The reduction of ABCG1 mRNA level in patient group when compared to control group was discovered (p < 0.05). Reduction of macrophage ABCG1 mRNA level was also associated with reduction in HDL cholesterol (R > 0.65, p < 0.001). These results suggest that ABCG1 transporter regulates HDL metabolism and cholesterol content and thereby protects against atherosclerosis.