[The role of tissue plasminogen activator in chronic subdural hematomas]

The role of tissue plasminogen activator (TPA) in chronic subdural hematomas was investigated. Fifteen cases of hematoma fluid and 26 cases of outer membrane and adjacent dura mater were used for the analysis, which were obtained at surgical treatment. Isolation of TPA was done by using a lysine-sepharose affinity chromatoculumn, then, TPA was measured by a fibrin plate method. The value of TPA in hematoma fluid was 0.035 +/- 0.018 IU/ml (mean +/- SD), that was extremely low. The value of TPA in the dura mater was 28.1 +/- 20.4 IU/g, which was significantly higher than that of normal dura mater. The values of TPA in the outer membrane were ranged widely from 12.1 to 123.6 IU/g (55.0 +/- 39.7 IU/g). In each case, however, TPA of the outer membrane was always higher than that of dura mater and they were highly related. TPA value of the outer membrane was tend to be high in the patients who had an obvious history of head injury and were treated surgically 40 to 60 days after the head injury. Some cases of posttraumatic subdural fluid collection were reported to be evoluted to chronic subdural hematomas at around 60 days after the head injury. From these facts, the changes of TPA activity may play a role in the evolution of chronic subdural hematomas. In relation to the pathological findings, TPA value was tend to be high in the cases that had a well developed sinusoidal layer. Since main location of TPA is in the endothelium, this result suggests that the sinusoidal layer may produce TPA.