Perioperative Evaluation of MMP-9-TIMP-1 System in Vascular Surgery Regarding Ischemic-reperfusion Injury

The MMP-9-TIMP-1 system has been implicated in many physiological and pathophysiological conditions including vascular surgery related ischemic-reperfusion injury. Our key aims were to establish the early perioperative time courses of the aforementioned system in aorto-bifemoral bypass and aorta stentgraft implantation procedures and to find correlation between the MMP-9-TIMP-1 system and the cross-clamp time. Patients were prospectively enrolled after Ethical Committee approval. Blood samples were taken at four different time points (T1-4): T1: right before surgery, T2: 60 min after the cross-clamp release, T3: first postoperative morning, T4: third postoperative morning. Plasma was isolated from heparin anticoagulated blood samples by low speed centrifugation at 4 °C, and stored at -80 °C until analyzed in a single batch at the end of the study. MMP- 9 and TIMP-1 were determined by the quantitative sandwich enzyme-linked immunosorbent assay (ELISA) techniques according to the manufacturer instructions (R\&D Systems Inc., Minneapolis, Minnesota, USA). In comparison with standard curves, the concentrations of MMP-9 and TIMP-1 in plasma were determined spectrophotometrically (Multiskan Ascent microplate photometer, Type: 354, Thermo Electron Corporation, Waltham, Massachusetts, USA) by reading the absorbance at 450 nm. Plasma concentrations of MMP-9 and TIMP-1 were expressed as ng/ml.