Relationship Between Circulating Plasma Matrix Metalloproteinase-9 (gelatinase-B) Concentration and Aortic Root Dilatation

Background Expression of matrix metalloproteinase (MMP) has been shown in aortic dissection and aneurysms indicating increased proteolysis compared with the normal aorta. However, its role in the development of aortic root dilatation has not been studied. We therefore attempted to determine the relationship between aortic root diameter and MMP-9 concentration in a hypertensive population. Methods The 53 hypertensive patients with (n = 27) and without aortic dilatation (n = 26) were included in the study. All participants underwent a complete transthoracic echocardiographic examination including aortic root measurement. Plasma concentration of MMP-9 were determined by the one-step sandwich enzyme immunoassay method and compared in both groups. Results Baseline demographic properties were similar in both groups. No subject had significant valvular disorder and wall motion abnormality on echocardiographic evaluation. On echocardiographic examination only five patients had bicuspid aortic valve. In patients with aortic root dilatation, 21 patients were using an antihypertensive agent, whereas in patients without aortic root dilatation, 19 patients were using an antihypertensive agent. Plasma MMP-9 level was significantly higher in patients with aortic root dilatation than in those without dilatation (2.5 ± 1.0 v 1.6 ± 0.9 ng/mL; P = .003). On correlation analysis, we found a positive correlation between aortic diameter and plasma MMM-9 levels (r= 0.43, P = .001). Conclusions Aortic root dilatation is associated with higher MMP release, which may indicate the role of increased collagenolytic and elastolytic activities in hypertension-induced aortic root dilatation.