Composition and metabolism of symptomatic distal aortic plaque

This study examines the composition of advanced human atherosclerotic lesions removed by endarterectomy and compares the collagen synthesis in the lesion with that of the intima-media layer of uninvolved vessel wall. The most striking feature of the lesions is an enormous accumulation of calcium that was raised more than tenfold, from a level of about 3% of dry tissue weight in the normal tissue to values approaching 50% in the pathologic specimens. The composition of the organic matrix was also altered. Elastin and glycosaminoglycan content decreased, whereas collagen content more than doubled, thus becoming the major component of the organic matrix. The cholesterol content increased severalfold above normal but even then accounted for less than 10% of the organic matrix. The lesion specimens synthesized collagen in vitro at a greater rate than normal tissue. The endarterectomy specimens with the highest calcium content exhibited the highest rate of collagen synthesis.