Elevated messenger RNA expression and plasma protein levels of osteopontin and matrix metalloproteinase types 2 and 9 in patients with ascending aortic aneurysms

Objective: Ascending aortic aneurysms result from a degenerative process in the aortic wall, characterized by the loss of smooth muscle cells and elastic fibers. We hypothesized that there would be changes in plasma protein and aortic tissue messenger RNA levels of osteopontin, matrix metalloproteinase type 2, matrix metalloproteinase type 9, and tissue inhibitor of matrix metalloproteinases type 1 in ascending aortic aneurysm samples.

Methods: Plasma, aortic tissue, and aortic mRNA samples were collected from patients with an ascending aortic aneurysm or an abdominal aortic aneurysm and from control individuals. Plasma protein levels of osteopontin, matrix metalloproteinase (MMP) types 2 and 9, and tissue inhibitor of matrix metalloproteinases type 1 were determined by quantitative sandwich enzyme-linked immunosorbent assay. Aortic mRNA levels of these same proteins were analyzed with the quantitative real-time polymerase chain reaction (RT-PCR) method and protein levels from the aortic tissues were assayed by immunostaining. Quantitative RT-PCR results were estimated by the normalized expression method (ΔΔCt).

Results: Plasma protein levels were significantly elevated for osteopontin, MMP-2, and MMP-9 in the samples of ascending and abdominal aortic aneurysm group compared with controls. Plasma protein levels of MMP-9 were higher in the nonoperated compared with the operated ascending aortic aneurysm group. Aortic osteopontin, MMP-2, and MMP-9 mRNA levels were increased for ascending aortic aneurysm samples.

Conclusions: This study reveals an important role of osteopontin, MMP-2 and MMP-9 in the development of ascending and abdominal aortic aneurysm.