RELATION OF PLASMINOGEN-ACTIVATOR INHIBITOR-1 ACTIVITY AND PLASMINOGEN-ACTIVATOR INHIBITOR-1 CONCENTRATION IN DIFFERENT PLASMA SAMPLES

The relationship between PAI activity, active PAI-1 concentration and whole PAI-1 concentration was determined in 180 plasma samples of unselected ambulant patients of the department of internal medicine. To exclude a release of platelet PAI-1 after blood sampling, different anticoagulants and temperatures of blood storage were tested. The comparison of PAI activity, measured by chromogenic substrate assay, and the active PAI-1 antigen showed a strong correlation between both methods in samples with normal and elevated PAI-1. The ratio whole PAI-1 antigen/active PAI-1 antigen was found in a very high range in plasma samples with normal PAI activity as well as in samples with elevated activity. It seems possible, that increased concentrations of whole PAI-1 antigen in comparison to lower values of active PAI-1 antigen are caused by elevated latent PAI-1. The results of the investigation of the influence of anticoagulants and conditions of blood storage indicates, that the release of PAI from platelets is prevented in Stabilyte anticoagulant in healthy donors. The obtained results point to the necessity to determine PAI activity and PAI-1 antigen. The measurement of PAI activity as active PAI-1 antigen allows a good comparison of the parts of PAI-1 in different states of diseases.