Expression and significance of cathepsin B in human abdominal aortic aneurysms

Objective:To study expression of cathepsin B in the vascular smooth muscle cells (VSMc) of patients with abdominal aortic aneurysms(AAA) and to investigate its underlying roles in pathogenesis of AAA.Method:Seventeen cases of AAA and 6 cases of normal abdominal aortas were collected in this study. HE staining,Van Gieson staining and immunohistochemical technique were used to evaluate the change of cathepsin B in the media of AAA.Result:Compared with the normal aortas patients, the content of collagen was increased in aneurysms to some extent. The average light density of α-smooth muscle actin of VSMC of AAA patients and control aortas respectively were 0.263 4±0.053 0 and 0.333 5±0.054 9, and the study showed that its expression were decreased significantly in AAA (P0.01). The average light density of cathepsin B of AAA and control aortas were 0.346 5±0.047 9 and 0.130 6±0.057 9, respectively . The expression of cathepsin B in the VSMC of AAA was higher than that of normal aortas patients, and the difference between them was statistically significant(P0.01).Conclusion:The high expression of cathepsin B in the VSMC may accelerate the development of AAA and participate in the disruption and remodeling of aneurysm wall.