1960s radioactive agent could pinpoint blockages in arteries

SCOTTISH scientists have discovered how a radioactive agent developed in the 1960s to detect bone cancer could prevent heart attacks and strokes by pinpointing calcium deposits in the arteries.

Hardening of arteries – known as atherosclerosis – is a serious condition where fatty deposits build up and clog the arteries.

Calcium is a key ingredient in these deposits, which can lead to a heart attack or stroke if pieces break away in arteries which supply blood to the brain or the heart.

The research, which is reported in the journal Nature Communications, could help in the diagnosis of these conditions in at-risk patients and in the development of new medicines.

Professor David Newby, British Heart Foundation (BHF) John Wheatley Professor of Cardiology at the Centre for Cardiovascular Science at Edinburgh University, said: “Hardening, or ‘furring’, of the arteries can lead to very serious disease, but it’s not clear why the plaques are stable in some people but unstable in others. We need to find new methods of identifying those patients at greatest risk from unstable plaques.”

The researchers from Edinburgh University and Cambridge University injected patients with sodium fluoride that had been tagged with a tiny amount of a radioactive tracer.

Using a combination of scanning techniques, the team tracked the tracer’s progress as it moved around the body.

Dr Anthony Davenport, from the department of experimental medicine and Immunotherapeutics at Cambridge, said: “Sodium fluoride is commonly found in toothpaste as it binds to calcium compounds in our teeth’s enamel.

“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.

“In fact, this new emerging technique is the only imaging platform that can non-invasively detect the early stages of calcification in unstable atherosclerosis.”

After the sodium fluoride scans, the patients had surgery to remove calcified plaques and the extracted tissue was imaged, using a laboratory scanner and an electron microscope.

This confirmed that the radiotracer accumulates in areas of active, unstable calcification, whilst avoiding surrounding tissue.

Dr James Rudd, a cardiologist and researcher from the department of cardiovascular medicine at Cambridge, said: “Sodium fluoride is a simple and inexpensive radiotracer that should revolutionise our ability to detect dangerous calcium in the arteries of the heart and brain.

“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.”

The study was funded by the Wellcome Trust, with contributions from the BHF, Cancer Research UK and the Cambridge NIHR Biomedical Research Centre.