Decreased tissue inhibitor of metalloproteinase-2/matrix metalloproteinase ratio in the acute phase of aortic dissection

Purpose. Aortic dissection is characterized by fragility of the tunica media, and matrix metalloproteinases (MMPs) are enzymes that degrade the extracellular matrix of the aorta. This study examines MMPs in patients with acute aortic dissection (AAD) in an attempt to elucidate the mechanisms of their actions. Methods. Enzyme-linked immunosorbent assays were used to measure the quantification of MMP-2, MMP-9, and the tissue inhibitor of metalloproteinase (TIMP)-2 in 30 patients with AAD, 12 patients with abdominal aortic aneurysm (AAA), and 16 control (CON) patients who underwent coronary artery bypass grafting. Results. MMP-2 and TIMP-2 were significantly lower in the AAD group than in the CON group, at 36 +/- 19 vs 58 +/- 30 (P < 0.01) and at 21 +/- 25 vs 216 +/- 130 (P < 0.001), respectively. The TIMP-2/MMP-2 ratio was 3.7 +/- 1.7 in the CON group and 0.9 +/- 0.8 in the AAD group (P < 0.001 vs CON), and the TIMP-2/MMP-9 ratio was 200 170 in the CON group and 37 80 in the AAD group (P < 0.001 vs CON). Conclusion. Low TIMP-2/MMP-2 and TIMP-2/MMP-9 ratios might play an important role in the onset of aortic dissection, when the tunica media becomes fragile with chronic breakage and degradation of the extracellular matrix.