OBJECTIVES: To investigate whether human veins responded to surgical handling with acute remodelling by measuring matrix metalloproteinase 9 (MMP9) expression and activity. DESIGN: Saphenous veins were collected from 24 patients (12 stable angina, 12 unstable angina) undergoing coronary artery bypass grafting. Expression of MMP9 and its regulators (plasminogen activators, plasminogen activator inhibitor-1, tissue inhibitor of metalloproteinase-1) was evaluated by semiquantitative RT-PCR in veins sampled at the start of and after surgical preparation, while protein was detected by western blotting. The proteolytic activity of MMP9 was analyzed by zymography. RESULTS: Gene (p=0.01) and protein (p=0.001) expression of MMP9 increased after surgical manipulation of vein grafts in all patients, accompanied by increased pro-MMP9 (p=0.04), but not active MMP9 (p=0.6). Grafts from stable patients had increased gene (p=0.05) and protein (p=0.006) expression, as well as increased pro- (p=0.04) and active (p=0.04) MMP9. Grafts from unstable patients increased only in MMP9 protein expression (p=0.05). The MMP9 regulators were unchanged. CONCLUSIONS: Surgical handling of vein grafts increased expression and activity of MMP9. However, the surgery-induced increase was attenuated in veins from unstable patients.
OBJECTIVES: To investigate whether human veins responded to surgical handling with acute remodelling by measuring matrix metalloproteinase 9 (MMP9) expression and activity. DESIGN: Saphenous veins were collected from 24 patients (12 stable angina, 12 unstable angina) undergoing coronary artery bypass grafting. Expression of MMP9 and its regulators (plasminogen activators, plasminogen activator inhibitor-1, tissue inhibitor of metalloproteinase-1) was evaluated by semiquantitative RT-PCR in veins sampled at the start of and after surgical preparation, while protein was detected by western blotting. The proteolytic activity of MMP9 was analyzed by zymography. RESULTS: Gene (p=0.01) and protein (p=0.001) expression of MMP9 increased after surgical manipulation of vein grafts in all patients, accompanied by increased pro-MMP9 (p=0.04), but not active MMP9 (p=0.6). Grafts from stable patients had increased gene (p=0.05) and protein (p=0.006) expression, as well as increased pro- (p=0.04) and active (p=0.04) MMP9. Grafts from unstable patients increased only in MMP9 protein expression (p=0.05). The MMP9 regulators were unchanged. CONCLUSIONS: Surgical handling of vein grafts increased expression and activity of MMP9. However, the surgery-induced increase was attenuated in veins from unstable patients.