In a new study performed in humans, researchers from Karolinska Institutet have determined the age of atherosclerotic plaques by taking advantage of Carbon-14 (14C) residues in the atmosphere, prevailing after the extensive atomic bomb tests in the 50ties and 60ties. The findings, published in the scientific online journal PLoS ONE, suggest that in most people plaque formation occurs during a relatively short and late time period in life of 3-5 years.
The investigators collected carotid plaques during carotid stenosis surgery at the Stockholm South General Hospital (Södersjukhuset). The patients were admitted for surgery since their carotid lesions partly obstructed the blood flow to the brain, causing symptoms of insufficient oxygen called Trans Ischemic Attacks (TIA) that in some cases also had lead to strokes.
The plaques were carbon dated at Uppsala University, by using Accelerator Mass Spectrometry (AMS). As a result of the extensive atomic bomb test in the 50-ties and 60-ties, the atmospheric concentration of 14C rapidly increased. Since then the concentration of 14C is declining, which now can be used to determine the time of synthesis of any biological sample.