Plaques can accumulate in the blood vessels and cause hardening of the arteries, which may ultimately result in a heart attack or stroke.
"We've developed a way to take non-invasive images of very early stage plaques, before they're detectable by any other means," said Samuel Wickline, professor of medicine and biomedical engineering at Washington University School of Medicine in St Louis. "This same technology, we think, will allow us to detect very early cancers and other inflammatory events as well."
To locate the capillaries, the scientists carried out magnetic resonance imaging (MRI) using 200 nm-long nanoparticles as labels. The particles were loaded with about 80 000 atoms of gadolinium as well as molecules that detect avb3 - a protein that is abundant in rapidly growing capillaries. The nanoparticles latch onto cells that contain avb3 and the gadolinium reveals their location by showing up as a bright spot on a magnetic resonance image. The scientists say that the nanoparticles contain many more gadolinium atoms than other carriers and so form brighter images.
"You can load these nanoparticles with whatever you want," added Wickline. "The targeting agent allows us to select where the particle goes, and then we can either add an imaging agent, such as gadolinium, or a drug, such as plaque-stabilizing medications or anticancer agents."
Wickline said that preliminary results suggest that the scientists can manipulate the nanoparticles to image plaques as they are just beginning to form. "Previous research of ours also suggests that this technique can distinguish between patients with stable plaques and those whose plaques are about to rupture and thereby cause a heart attack or stroke," he added.
The researchers reported their work at the American Heart Association's Scientific Sessions 2002 in Chicago, US. The technology used in the study has been licensed to Kereos, a company specializing in molecular imaging and targeted therapeutics that was founded by Wickline and his colleague Gregory Lanza.