Expression and localization of vascular endothelial growth factor in normal abdominal aorta and abdominal aortic aneurysm.

AIM: The genesis of abdominal aortic aneurysms is associated with remodeling of the vascular wall by angiogenesis as well as proteolysis. Vascular endothelial growth factor (VEGF) is known to be a regulator of angiogenesis and to simultaneously stimulate elastolytic proteinases. We analyzed the expression and localization of VEGF in human abdominal aortic aneurysms compared to normal human aorta
METHODS: Eighteen infrarenal aortic aneurysm samples were collected at the time of abdominal aortic aneurysm surgery, while nine normal aortic samples were obtained from autopsy specimens. Immunohistochemical staining was performed to detect VEGF. Immunoenzyme or immunofluorescent double staining was also used to identify those cells presenting VEGF.
RESULTS: VEGF was expressed in 18 (100%) of the 18 abdominal aortic aneurysm samples, while 0 (0%) in the 9 normal abdominal aorta samples. Of the 18 samples of aneurysms, all 18 displayed positive VEGF immunostaining in macrophages, 12 in smooth muscle cells (SMCs), and 9 in endothelial cells (ECs).
CONCLUSION: Our study clearly demonstrated the expression of VEGF in ECs, and SMCs, and macrophages of abdominal aortic aneurysms as well as its absence in those cells of normal abdominal aorta, suggesting that VEGF may play an important role in aneurysm formation via its direct and/or indirect actions.