TISSUE-PLASMINOGEN ACTIVATOR AND PLASMINOGEN-ACTIVATOR INHIBITOR-1 DETECTED IN BLOOD AFTER CATARACT-SURGERY

In order to study the changes of fibrinolytic enzymes in the blood after surgery, 139 cataract patients underwent pre- and postoperative blood assays to determine the activities of tissue plasminogen activator (t-PA), t-PA antigen, and plasminogen activator inhibitor-1 (PAI-1) antigen and to calculate the t-PA index [(t-PA activity/t-PA antigen) X 100] and T/P 100 [(t-PA antigen/PAI-1 antigen) X 100] values. The t-PA activity was determined by a modified bioimmunoassay using monoclonal antibody (SP-322), which binds with a characteristic epitope distinct from the active site of t-PA. The t-PA antigen was detected by ELISA using SP-322 as the primary antibody. Concentrations of PAI-1 antigen were determined by ELISA. Postoperative t-PA activity peaked on the first day, then gradually decreased. Baseline concentrations of t-PA activity were observed after the ninth day; recrudescence between the fifteenth and twenty-first days. The t-PA index, which is the ratio of functionally active t-PA to inactive t-PA, was maximally elevated on the first postoperative day, then returned slowly to preoperative concentrations after the ninth day. T/P 100, which is calculated as the ratio of inactive t-PA to a specific inhibitor, PAI-1, was lower on the second and third days and higher on the fourth and fifth days than preoperative levels. In conclusion, even after minor surgery such as cataract surgery, functionally active t-PA in the blood increased significantly and required more than two weeks to return to normal values. These results suggest that fibrinolytic fluctuations may be an important objective indicator of complete recovery after cataract surgery.