Atherosclerosis – where fatty calcium deposits clog up arteries and reduce blood flow
and oxygen supply – can lead to heart attacks and strokes. Now, a team says it is possible to
identify the early stages of this process on a noninvasive imaging system thanks to an
inexpensive, repurposed radioactive agent.
In some cases of atherosclerosis, pieces can break
off from the calcium deposits.
In Nature Communications, researchers from the universities of Cambridge and
Edinburgh in the UK, describe how they used a radioactive agent that was first developed in
the 1960s to detect bone cancer to highlight the build-up of unstable calcium deposits in
patients’ arteries.
Study leader Dr. Anthony Davenport, of the department of medicine at Cambridge,
says this “new emerging technique is the only imaging platform that can noninvasively detect
the early stages of calcification in unstable atherosclerosis.”
He and his colleagues expect the technique – which uses sodium fluoride tagged with a tiny
amount of radioactive tracer – will help diagnose atherosclerosis and develop new drugs to
treat it.
There are several ways atherosclerosis can be dangerous. One way is that the gradual
build-up of fatty deposits (known as “plaques”) gradually harden and narrow the artery wall,
eventually restricting blood flow and oxygen supply.
Not clear which patients will develop dangerous, unstable calcium deposits
Another way that atherosclerosis can be dangerous is that in some cases, pieces can break
off from the calcium deposits. If that happens in an artery that supplies the brain or the
heart, it can cause a blockage that results in stroke or heart attack.
While it is clear that atherosclerosis can lead to very serious disease, what is not so
clear is which people will develop the unstable plaques that allows pieces to break off – so
the earlier they can be identified, the better the chances that early treatment will save
lives.
For their study, the team injected patients with the radiotracer version of sodium
fluoride (18F-NaF).
Then, using a combination of imaging techniques (positron emission tomography
and computed tomography, or PET/CT), they tracked the tracer as it moved around
the body.
“Sodium fluoride is commonly found in toothpaste as it binds to calcium compounds in our
teeth’s enamel,” Dr. Davenport explains, “In a similar way, it also binds to unstable areas of calcification in
arteries and so we’re able to see, by measuring the levels of radioactivity, exactly where
the deposits are building up.”
Sodium fluoride tracer should ‘revolutionize’ detection of dangerous calcium
deposits
After undergoing the scans, the patients had surgery to remove the plaques in their
arteries. The researchers then examined them at a higher resolution using a laboratory
PET/CT scanner and an electron microscope.
This detailed examination confirmed that the 18F-NaF tracer builds up in areas of
active, unstable calcium deposits, and not in surrounding tissue.
Co-author, Dr. James Rudd, a cardiologist and researcher at Cambridge, says 18F-NaF is a
simple and inexpensive tracer that should “revolutionize” the ability of doctors to detect
dangerous calcium deposits in the arteries of the heart and brain. He concludes:
“This will allow us to use current treatments more effectively, by giving them
to those patients at highest risk. In addition, after further work, it may be possible to use
this technique to test how well new medicines perform at preventing the development of
atherosclerosis.”
Most of the funds for the study came from the Wellcome Trust, supplemented with
contributions from the British Heart Foundation, Cancer Research UK and the Cambridge NIHR
Biomedical Research Centre.
In February 2015, Medical News Today learned how researchers are working on a way
to get nanomedicines to treat atherosclerosis. Writing in
Science Translational Medicine, a Harvard-led team describes how they developed
nano-sized “drones” that deliver targeted drugs and repair arteries. The tiny particles were
small and sticky enough to push their way under the calcified deposits and effect repair.
Written by Catharine Paddock PhD
Copyright: Medical News Today