CATHEPSIN-D AND CATHEPSIN-L ACTIVITIES IN AORTIC-ANEURYSM WALL AND PARIETAL THROMBUS

Deterioration of the aortic wall resulting in formation of aneurysms m ay be caused by increased activity of metalloproteases and lysosomal p roteases. The aim of this work was the evaluation of cathepsin D and c athepsin L activities, and activities of inhibitors of cysteine cathep sins in the wall of aortic aneurysms and in parietal thrombus. Aortic aneurysms were obtained during operation. Aortas taken from organ dono rs and blood clots were used as control material. Activities of cathep sin D and cathepsin L in the aortic aneurysm wall and parietal thrombu s were higher than in the control groups. The aneurysm wall showed low er activity of inhibitors of cysteine proteases than the normal aorta. Parietal thrombus had a higher level of cysteine protease inhibitor a ctivity than blood clot. Cathepsin D and cathepsin L present in the an euerysm wall and in the parietal thrombus filling the aneurysm may act on proteins determining elasticity and mechanical resistance of arter ies.