Imaging of native high-density lipoprotein in human coronary plaques by color fluorescent angioscopy.

High-density lipoprotein (HDL) plays a key role in reverse cholesterol transport, and halts the progression of atherosclerosis. The aim of the present study was to visualize native HDL in the human coronary arterial wall. The fluorescence characteristics of HDL were investigated by color fluorescent microscopy (CFM) using excitation at 470 nm and emission at 515 nm with Fast green dye (FG) as the biomarker. HDL in 30 normal coronary segments, and in 25 white and 25 yellow plaques in excised human coronary arteries, was visualized by color fluorescent angioscopy (CFA) and CFM. Localization of HDL visualized by CFM was compared with that stained by immunostaining using an anti-HDL antibody. FG elicited a characteristic brown fluorescence of HDL. By CFA, the percent incidence of HDL in normal segments, white (early stage of plaque growth) and yellow (advanced stage of plaque growth) plaques was, respectively, 33%, 76% (P<0.05 vs. normal segments and yellow plaques) and 21%. Localization of HDL visualized by CFM did not differ from that stained by immunostaining. In the human coronary arterial wall, HDL deposits infrequently in normal segments, but increasingly deposits with plaque formation, and decreases in the advanced stage of plaque growth.