Assessment of the role of pancreatic proteases in human abdominal aortic aneurysms and occlusive disease.

Previous studies on the pathogenesis of abdominal aortic aneurysms have shown both elastase-like activity in the aortic wall and a decreased elastin content. The present study, using specific radioimmunoassays for pancreatic elastase 2 (IRE2) and cationic trypsin(ogen) (IRCT), investigates the concentrations of these proteases which are known to circulate in blood, in abdominal aortic aneurysms. Aortic specimens were obtained from 32 patients with aneurysms and 21 patients with atherosclerotic occlusive disease. Aortic tissue, obtained at autopsy from young adults, served as controls. Elastase-like activity was 300% and 800% higher, respectively, in aortic homogenates from aneurysms in comparison to occlusive disease and control aortic tissue. This was associated with 1.4-fold higher level of IRE2 and 2.7-fold higher levels of IRCT as compared to occlusive disease. Although there was no significant difference in the aortic collagen concentration among all 3 groups, the elastin content of aneurysmal aorta was 85% and 74% lower, respectively, in comparison to control and occlusive aorta. The results of this investigation demonstrate the presence of pancreatic elastase 2 and cationic trypsin(ogen) in abdominal aortic aneurysmal tissue and suggest that circulating pancreatic proteases contribute to the pathophysiology of aneurysms of the infrarenal aorta.