BACKGROUND: Matrix metalloproteinases (MMPs) constitute a family of zinc-dependent proteases (endopeptidases) whose catalytic action is the degradation of the extracellular matrix components. In addition, they play the major role in the degradation of collagen and in the process of tissue remodeling. The present clinical study investigated blood serum levels of metalloproteinases- 1, -2, -3 and -9 in patients with acute and chronic aortic dissection, thoracic aortic aneurysm and acute myocardial ischemia compared to healthy individuals.METHODS: The blood serum levels of MMP-1, -2, -3 and -9 were calculated in 31 patients with acute aortic dissection, 18 patients with chronic aortic dissection, 18 patients with aortic aneurysm and in 13 patients with acute myocardial ischemia, as well as in 15 healthy individuals who served as the control group. Serum MMP levels were measured by using an ELISA technique.RESULTS: There were significantly higher levels of MMP-3 in patients with acute myocardial ischemia as compared to acute aortic dissection (17.33 +/- 2.03 ng/ml versus 12.92 +/- 1.01 ng/ml, p < 0.05). Significantly lower levels of MMP-1 were found in healthy controls compared to all groups of patients (1.1 +/- 0.38 ng/ml versus 2.97 +/- 0.68 in acute aortic dissection, 3.09 +/- 0.98 in chronic dissection, 3.16 +/- 0.51 in thoracic aortic aneurysm and 4.58 +/- 1.04 in acute myocardial ischemia, p < 0.05). Higher levels of MMP-1 and MMP-3 were detected on males. There was a positive correlation with increasing age (r = 0.38, p < 0.05). In patients operated for acute type A aortic dissection, the levels of MMP-1, MMP-3 and MMP-9 increased immediately after surgery, while the levels of MMP-2 decrease. At 24 hours postoperatively, levels of MMP -1, -2 and -9 are almost equal to the preoperative ones.CONCLUSION: Measurement of serum MMP levels in thoracic aortic disease and acute myocardial ischemia is a simple and relatively rapid laboratory test that could be used as a biochemical indicator of aortic disease or acute myocardial ischemia, when evaluated in combination with imaging techniques.