Beta carotene uptake into atherosclerotic plaque: enhanced staining and preferential ablation with the pulsed dye laser.

Overview

The yellow color of atherosclerotic plaque is due to the presence of carotenoids, which absorb light between 430-530 nm and account for the preferential ablation of plaque by the pulsed dye laser operating at 480 nm. This study was designed to examine tissue uptake of beta-carotene and the effect of uptake on arterial plaque ablation. Forty-two atherosclerotic NZW rabbits were given intravenous beta-carotene at a dose of 40 mg/kg, twice weekly and killed between 1 hour and 28 days after the initial injection. beta-carotene was not detected in control specimens but was significantly greater in plaque than in normal wall at all time points following beta-carotene injection (P < 0.04 Mann Whitney U test). The ablation threshold was significantly lower in beta-carotene treated plaque than in untreated plaque or normal arterial wall (P < 0.01, Fisher's exact test). In this model beta-carotene is preferentially taken up into arterial plaque, resulting in increased absorption of laser radiation at 480 nm and enhanced tissue ablation.