Plasma levels of matrix metalloproteinase-9 and tissue inhibitor of metalloproteinase-1 are increased in the coronary circulation in pa with acute coronary syndrome

Background Previous studies on atherectomy specimens from patients with acu te coronary syndrome (ACS) implicated the role of proteolytic enzymes. We e xamined whether the plasma levels of matrix metalloproteinase-9 (MMP-9) and tissue inhibitor of metalloproteinase-1 (TIMP-1) were increased in the cor onary circulation in ACS. Methods and Results The plasma levels (nanograms per milliliter) of MMP-9 a nd TIMP-1 in the aorta (Ao) and great cardiac vein (GCV) were measured in 2 9 patients with ACS (20 with acute myocardial infarction [group 1] and 9 wi th unstable angina [group 21), 17 with stable effort angina (group 3), and 20 control subjects (group 4). Group 1 patients had occlusion in the left a nterior descending artery (LAD), and groups 2 and 3 patients had culprit le sion in the LAD. In group 1 blood samples were obtained at the time of dire ct coronary angioplasty done within 12 hours after the onset. The Ao level of either MMP-9 or TIMP-1 did not differ among the 4 groups. The GCV-Ao dif ferences in MMP-9 and TIMP-1 were both significantly increased in groups an d 2 compared with those in group 4. Neither of them was different between g roups 3 and 4. Neither the GCV-Ao difference in MMP-9 or TIMP-1 level was c orrelated with the maximal creatine kinase level in group 1. Conclusions Increased plasma levels of MMP-9 and TIMP-1 were detected in th e coronary circulation in ACS patients, suggesting a process of active plaq ue rupture in ACS.