989-56 Serial Changes of Plasma Vitronectin Level in Patients with Acute Myocardial Infarction: Possible Role of VN as a Scavenger of Plasminogen Activator Inhibitor-1

Vitronectin (VN) is an adhesive glycoprotein that promotes cell adhesion and spreading and located in mainly extracellular matrix. VN is also known to regulate the fibrinolytic system by forming complexes with plasminogen activator inhibitor (PAI)-1. To elucidate the serial changes of plasma VN level in association with fibrinolytic capacity in patients with acute myocardial infarction (AMI), we measured plasma levels of VN as well as PAI activity. PAI-5 antigen and tissue plasminogen activator (t-PA)-PAI-1 complexes antigen in 20 consecutive AMI patients. All patients were administered alteplase 0.45 mg/kg intravenously for coronary thrombolysis. Blood sampling was done on admission, 4, 8, 12, 16, 20, 24 and 48 hours; 3, 4, 5, 6 and 7 days after admission. PAl activity. PAI-1 antigen and t-PA-PAI-1 complexes antigen levels were increased 4 hours after admission (p l 0.01 vs admission) and the levels maintained higher level during the first 24 hours. On the other hand, VN levels were increased at 48 hours (p l 0.01 vs admission) and showed a tendency to be high until 7 days. In contrast to the VN level, PAl activity, PAI-1 antigen and t-PA-PAI-1 complexes antigen levels were decreased after 48 hours (p l 0.05 vs 4 hours). We conclude that VN is increased 48 hours after admission with complementary decreasing of PAI-1 in AMI patients. It is possible that VN removes PAI-1 from the circulation to the extracellular matrix where VN exists by forming the complexes. These results suggest that VN may act as a scavenger of PAI-l and playa protective role for the fibrinolytic system in patients with AMI. Download : Download high-res image (114KB) Download : Download full-size image