Detection of Serum Matrix Metalloproteinase-9
Matrix metalloproteinase-9 (MMP-9) is an important diagnostic biomarker in aortic pathophysiology in which MMP-9 can weaken the aortic media by degrading multiple extracellular components and DM patients have a 2-fold decreased level of MMP-9, which could restrict the degradation of the aortic wall [12] . Plasma MMP-9 was measured by using an enzyme-linked immunosorbent assay (ELISA), designed by R&D Systems (Minneapolis, MN, USA), according to the manufacturer’s instructions and protocols. Venous blood was drawn from all patients at admission (within 24 hours of symptom onset) and plasma samples were obtained after centrifugation at 3500 rpm at 4 °C for 15 min immediately after collection and then stored at −80 °C for further analysis. The MMP-9 level was measured on admission, at day 14 (after the acute phase) and day 90 (after the subacute phase), at 6 and 12 months and then annually during follow-up.