Expression of a disintegrin and metalloprotease in human abdominal aortic aneurysms.

OBJECTIVES The a disintegrin and metalloprotease (ADAM) family of metalloproteases possesses a proteolytic function and activates various inflammatory factors. Their expression pattern in an abdominal aortic aneurysm (AAA) is as yet unknown. The aim of this study was to make a detailed analysis of the expression of ADAMs 8, 9, 10, 12, 15 and 17, and their tissue inhibitors of metalloprotease (TIMP)-1 and TIMP-3 in patients with AAA. DESIGN The aortic vessel walls of AAA patients (n=20) and non-aneurysmal aortic specimens (n=10) were obtained by conventional surgical repair and autopsy. SYBR green-based real-time PCR, histology and immunohistochemistry were performed on all samples. MAIN OUTCOME MEASURES Quantitative expression analysis and the localisation of various ADAMs in AAA. RESULTS ADAMs tested in our study were expressed in both AAA and control aorta without any significant differences between the groups. In contrast, expression of TIMP-1 was significantly reduced in AAA compared to control vessels. Smooth muscle cells (SMCs), neovessels and macrophages were positive for all ADAMs and TIMPs tested. Infiltrates were negative for TIMP-3, and luminal endothelial cells were positive for ADAMs 15 and 17. A significant positive correlation was observed between ADAMs 10, 12, 15, 17, TIMP-3 and SMCs. CONCLUSION ADAMs are constitutively expressed in normal aortic vessel walls and AAA, particularly in SMCs.