Apatite - Cholesterol Agglomerates in Human Atherosclerotic Lesions

The purpose of this study was to examine the ul trastructural relationships of cholesterol crystals and apatite deposits in human atherosclerotic lesions. Segments of human aortic atherosclerotic lesions were obtained at autopsy , fixed in gl utaraldehyde and dehydrated without using any organic solvents. The aortic segments were coated with carbon and subjected to various scan ning electron microscope analyses. These included secondary electron imaging , back scattering of primary electrons, energy dispersive X-ray analysis of selected spots followed by area mapping of calcium and phosphorus , and cathodoluminescence. The information gathered from scanning of selected areas in the lesions by all the techniques showed that cholesterol crystals and apatite deposits are close to each other, within 10 μm distance or less. Cholesterol crystals are often surrounded by or adjacent to apatite. The results indicate that cholesterol and apatite crystals form closely linked agglomerates in human ath erosclerotic lesions. Further studies are needed to determine whether precipitation of calcium and cholesterol are somehow linked during atherosclerotic lesion development.