[Lysosomal proteinases of the human aortal intima and atherogenesis]

Activity of lysosomal proteinases cathepsins A, B, C, D and L was studied in cultivated cells of human aorta intima, isolated from intact zone of aorta, from lipid stria and atherosclerotic patch. The highest enzymatic activity was detected in the lipid stria cells and the lowest activity - in atherosclerotic patch. Atherogenous blood serum, added simultaneously with pepstatin or leupeptine into the cell culture of intact aorta, caused a distinct increase in the proliferating activity of these cells and in the level of cholesterol accumulation, while activities of cathepsin D or B and L were inhibited by 80-100%, respectively. The data obtained suggest that lysosomal proteolytic system plays an important role in development of atheromatous impairment of vascular wall.