Elemental changes in atherosclerotic lesions using nuclear microscopy.

The roles of iron and other trace metals in the aetiology of heart and brain diseases has been a subject of keen research because of the ability of metal ions to participate in reactions involving free radicals, which have been implicated in many of these diseases. Unstained freeze dried tissue sections from the aorta of New Zealand white rabbits fed with a 1% cholesterol diet for 12 weeks were scanned with a 2 MeV proton beam using the National University of Singapore nuclear microscope facility. Results from 6 test and 4 control rabbits show that there is an average of seven-fold increase in iron and an average of nearly two-fold increase in phosphorus in the atherosclerotic lesion compared with healthy tissue. The increase in iron adds weight to the hypothesis that iron-catalyzed free radical reactions may be associated with the development of atherosclerosis. A depletion of other elements analyzed was seen in the lesion. Elemental mapping also showed the occurrence of granules rich in sodium, chlorine and potassium at the interface between lesioned and non-lesioned tissue.