ABSTRACT
The type-1 plasminogen activator inhibitor (PAI-1) is probably the most regulated component of the entire fibrinolytic system, and is present in increased concentrations in many different disease states. PAI-1 activity and antigen are the two parameters of the fibrinolytic system that vary most widely. Restriction fragment length polymorphism studies of the PAI-1 gene revealed two alleles at the 3' untranslated end of the gene. Elevated levels of PAI-1 have been found to be associated with deep vein thrombosis (DVT) and arterial thrombotic events in patients with atherosclerosis, particularly in coronary heart disease, myocardial infarction, and stroke. For patients with an established episode of DVT the evidence for an association between elevated PAI-1 levels and the risk to experience a further episode of a thromboembolic event is weak. In apparently healthy volunteers, two of the components of the fibrinolytic system, namely t-PA and PAI-1, fluctuate quite remarkably during a 24-h period.
