Editors' ChoiceDrug Delivery

Destination: Stent

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Science Translational Medicine  02 Jun 2010:
Vol. 2, Issue 34, pp. 34ec89
DOI: 10.1126/scitranslmed.3001316

Stent angioplasty—in which obstructed blood vessels are first widened with a balloon catheter and then kept open with a narrow tube, the stent—has become the treatment of choice for a variety of occlusive vascular diseases. Drug-eluting stents, which carry antiproliferative agents such as paclitaxel or sirolimus to block the growth of excess fibrous tissue, are often used; they reduce the risk of re-occlusion by 20 to 30% as compared with bare metal stents. However, drug-eluting stents deliver the pharmacologic agent at a fixed dose that cannot be modified or replenished and have not been uniformly effective in all clinical settings. Furthermore, recent evidence suggests that drug-eluting stents can increase the risk of late complications such as stent thrombosis (during which a clot forms in the stent), myocardial infarction, and sudden death. Now, Chorny et al. introduce a more versatile strategy of targeting drugs to stents with the use of magnetic nanoparticles.

Building upon their previous experience of delivering endothelial cells loaded with magnetic nanoparticles to stented arteries, the researchers fabricated nanoparticles impregnated with paclitaxel. In cell culture, paclitaxel-carrying magnetic nanoparticles released the drug over two days and effectively inhibited the proliferation of vascular smooth muscle cells. In rats, brief exposure to an electromagnetic field was sufficient to specifically target the carrier particles to stents placed in the carotid artery. With this strategy, paclitaxel significantly inhibited vessel wall thickening and the reoccurrence of vessel narrowing at doses considerably lower than those currently used in drug-eluting stents.

Chorny et al. have demonstrated the feasibility of a unique drug delivery strategy based on targeting nanoparticles to stented arteries with a magnetic field. Although the safety and efficacy of this approach will need to be examined in future studies, the delivery of therapeutic agents with magnetic nanoparticles holds tremendous potential for the prevention and treatment of the re-occlusion of stented blood vessels.

M. Chorny et al., Targeting stents with local delivery of paclitaxel-loaded magnetic nanoparticles using uniform fields. Proc. Natl. Acad. Sci. USA 107, 8346–8351 (2010). [Abstract]

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