Detection of impaired fibrinolytic activity in coronary artery disease--electrophoretic and immuno-blotting analysis of tissue plasminogen activator

In present study, we investigated the fibrinolytic activities and plasma antigen levels of tissue plasminogen activator (tPA) before or after a submaximal exercise in patients with coronary artery disease (CAD). We also investigated tPA phenotypes in plasma by electrophoretic and immuno-blotting analysis. Euglobulin fractions obtained from plasma were submitted to sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) followed by immunoblotting analysis. There were no differences in plasma antigen levels of tPA between the study group and controls before or after the exercise, however CAD patients showed lower fibrinolytic activities after the exercise than controls. SDS-PAGE followed by immuno-blotting with an antisera against human tPA revealed two bands at molecular weights (m.w.) of 70,000 and 120,000. The band at m.w. of 70,000 corresponded to free tPA and that of 120,000 was considered to be identical to a complex of tPA with its inhibitor. Furthermore, we found a decrease in free tPA in the patients with low fibrinolytic activities. From these results it was concluded that impaired fibrinolytic activities, probably due to decreased free tPA, observed in CAD patients, might be an important factor in the pathogenesis of CAD.