In vivo transfer of lipoprotein(a) into human atherosclerotic carotid arterial intima.

The aim of this study was to compare the atherogenic potential of lipoprotein(a) [Lp(a)] and LDL by measuring the intimal clearance of these two plasma lipoproteins in the atherosclerotic intima of the human carotid artery in vivo. Autologous 131I-Lp(a) and 125I-LDL were mixed and reinjected intravenously 3 hours before elective surgical removal of the arterial intima in four patients. The intimal clearance of Lp(a) and LDL was 229+/-48 and 405+/-127 nL/cm2 per hour, respectively (paired t test; P=.12). The mass accumulation of Lp(a) (114+/-32 ng/cm2 per hour) was on average one 15th that of LDL (paired t test; P=.06), mainly reflecting a low plasma concentration of Lp(a) compared with LDL in the human subjects studied. In accordance with our previous observation in rabbits, there was a positive association between the intimal clearance of LDL and that of Lp(a) (r=.97, P=.03). Accordingly, high plasma levels of Lp(a) may share with LDL the potential for causing lipid accumulation in the arterial intima in humans.