Calcium-acidic phospholipid-phosphate complexes in human atherosclerotic aortas

Since aortic calcification chemically resembles bone mineralization, we tested the hypothesis that a bone mineral nucleator, the Ca-acidic phospholipid-phosphate complexes, is found in atherosclerotic plaques. Calcium-acidic phospholipid-phosphate complexes were isolated from hydroxyapatite-containing calcified plaques and from adjacent nonmineralized areas of adult human aortas. Neonatal aortas, which served as nonmineralized lesion-free controls, contained negligible amounts of the Ca-acidic phospholipid-phosphate complexes. The concentration of complexed acidic phospholipids in the aortic plaques (5 micrograms/mg demineralized dry wt) was comparable to that found in newly mineralized bone and calcified cartilage. The presence of Ca-acidic phospholipid-phosphate complexes in the nonmineralized regions of the adult aorta, as well as in the mineralized plaques, suggests that this tissue may calcify through mechanisms similar to those involved in bone mineralization.