Fluoride is good for teeth—and for identifying unstable atherosclerotic plaque

A new study shows that sodium fluoride—the active ingredient in toothpaste—can also be used to identify unstable calcified atherosclerotic plaques, according to researchers in the United Kingdom.

“Sodium fluoride is a simple and inexpensive radiotracer that should revolutionize our ability to detect dangerous calcium in the arteries of the heart and brain,” said study co-author James Rudd, PhD, of Department of Cardiovascular Medicine at the University of Cambridge.

The technique, reported in the journal Nature Communications, could facilitate diagnosis of atherosclerosis in at-risk patients, and potentially help in the development of new medicines.

In this study, the researchers injected patients with sodium fluoride that was tagged with a radioactive tracer. Using a combination of scanning techniques—including positron emission tomography (PET) and computed tomography (CT)—the researchers were able to track the progress of the tracer.

“Sodium fluoride is commonly found in toothpaste as it binds to calcium compounds in our teeth’s enamel,” said Anthony Davenport, BSc, PhD, of the Department of Experimental Medicine and Immunotherapeutics at the University of Cambridge, who led the study. “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.”

Specifically, they found that the fluoride binds to unstable “microcalcifications,” which are a key feature of high-risk atheroma and are associated with increased morbidity and mortality. “Macrocalcifications,” on the other hand, confer plaque stability. Until this discovery, CT systems could not detect microcalcifications, but only identify large areas of macrocalcification.

“This new emerging technique is the only imaging platform that can non-invasively detect the early stages of calcification in unstable atherosclerosis,” Dr. Davenport said.

Following their sodium fluoride scans, the patients had surgery to remove calcified plaques. The extracted tissue was imaged using a laboratory PET/CT scanner and an electron microscope. This confirmed that the radiotracer accumulated on areas of active, unstable calcification while avoiding surrounding tissue.

If further studies confirm these findings, “it may be possible to use this technique to test how well new medicines perform at preventing the development of atherosclerosis,” Dr. Rudd said.

The researchers also predict this discovery could have wide-ranging applications to study active calcification across many disease areas and disciplines.