Activity and localization of cathepsin B, D and G in aortic aneurysm.

The activities of cathepsin B, D and G, and their distribution in the walls of normal aorta and those of aneurysms of abdominal aorta were studied. The immunohistochemical reaction for these cathepsins was positive in the aneurysm wall both in the cells and in the extracellular matrix. It was more apparent than in normal aortas. The activities of cathepsin B, D and G in aneurysm were 1.5 times higher than in normal aortas. It may be suspected that besides the action of collagenases and elastases the cathepsins participate in an enhanced degradation of collagen and elastin fibers of aneurysm wall.