JUNE 2003

Agent delivers drugs and boosts MR contrast

By: Charles Bankhead

CONTEXT: Researchers have shown that tissue factor-targeted nanoparticles can penetrate and bind stretch-activated vascular smooth muscles in vessel media after trauma from balloon angioplasty. Taking the next step, they examined whether nanoparticles targeting av§3 in vascular smooth muscle cells (VSMC) can be used as a drug delivery platform for antirestenosis therapy.

RESULTS: Assistant professor Dr. Gregory M. Lanza and colleagues at Washington University in St. Louis successfully targeted drug-bearing nanoparticles to VSMC (Circulation 2002;106:2842-2847). T1-weighted MRI demonstrated adherence of the nanoparticles to the target cells. Nanoparticle adherence to the cells significantly inhibited proliferation in culture for three days. In vitro dissolution studies demonstrated that nanoparticle drug release persisted for one week.

IMAGE: High-resolution MRI microscopy reveals the distribution of tissue factor-targeted nanoparticles in targeted vascular smooth muscle tissue. (Provided by G. Lanza)

IMPLICATIONS: The targeted drug delivery approach to atherosclerosis or restenosis has advantages over drug-eluting coronary stents that have shown considerable promise for the same application. The nanoparticle strategy may also enable MR to detect vascular hot spots that represent vulnerable atherosclerotic plaque.