Hyaluronic acid nanoparticles for active targeting atherosclerosis.

For the effective diagnosis and therapy of atherosclerosis, there is a pressing need to develop the carrier which can specifically deliver the agents to the pathological site. Since the representative hallmark of atherosclerosis in its pathogenic process is the over-expression of the receptors for hyaluronic acid (HA) such as stabilin-2 and CD44, we herein investigated the potential of HA nanoparticles (HA-NPs) as the carrier for active targeting atherosclerosis. From in vitro cellular uptake tests, it was revealed that HA-NPs were selectively taken up by the cells over-expressing stabilin-2 or CD44. On the other hand, the cellular uptake of HA-NPs was drastically reduced when the cells were pre-treated with excess amount of free HA, implying that HA-NPs were taken up by the receptor-mediated endocytosis. Following systemic administration of Cy5.5-labeled NPs into the ApoE-deficient mice as the animal model, the atherosclerotic legion was assessed at 24 post-injection by using the optical imaging system. Interestingly, the fluorescent signal of the atherosclerotic lesion by HA-NPs was much stronger than that of the normal aorta. Three dimensional z-stack images of an atherosclerotic plaque indicated the even distribution of HA-NPs in the atherosclerotic legion. It was demonstrated by immunohistochemistry that HA-NPs were co-localized with the HA receptors including stabilin-2 and CD44. In addition, the amount of HA-NPs, accumulated in the atherosclerotic lesion, was much higher than that of HGC-NPs, known to reach the atherosclerotic lesion by the passive targeting mechanism. Overall, it was evident that HA-NPs could effectively reach the atherosclerotic lesion via the active targeting mechanism after systemic administration, implying their high potential as the carrier for diagnosis and therapy of atherosclerosis.