Summary
The association of increased PA-inhibitor (PAI) activity and of PAI-1 and PAI-2 antigen
levels with different pathological conditions was studied in a collective of over
300 patients. PAI-1 and PAI-2 levels were measured by specific radioimmunoassays.
A good correlation was observed of PAI activity with PAI-1 antigen (r = 0.718; p <0.0001)
but not with PAI-2 (r = 0.070; n.s.). Both in the controls and in the patients, PAI
activity and PAI-1 antigen showed an extremely large range of values. PAI activity
ranged from 0.5 to 68 U/ml and PAI-1 antigen from 6 to 600 ng/ml. Increased PAI activity
and PAI-1 antigen was observed in patients with malignant tumors, cardiovascular or
thromboembolic disease, in the postoperative phase, with hepatic insufficiency, after
trauma and after extracorporeal circulation. The large spectrum of disease states
with increased PAI activity and PAI-1 antigen reinforces previous suggestions that
PAI-1 is an acute phase reactant. After extracorporeal circulation, PAI activity and
PAI-1 concentrations strongly increased within one hour, remained elevated for at
least one week and returned to preoperation values within 7 days.
PAI-2 values ranged from below detection limit (15 ng/ml), observed in half of the
plasmas, to 485 ng/ml in a pregnant woman. High values of PAI-2 were only observed
in pregnancy.
Key words
Tissue-type plasminogen activator - Urokinase - Plasminogen activator inhibition -
Plasminogen activator inhibitor type 1 and 2