Release of vascular plasminogen activator (v-PA) after venous stasis: electrophoretic-zymographic analysis of free and complexed v-PA.

To better characterize the plasminogen activators present in the euglobulin fraction (EF) of plasma before and after venous occlusion, euglobulins of 30 healthy volunteers and of 32 patients with idiopathic thromboembolic disease were submitted to SDS-PAGE and zymographic detection. The patterns thus obtained were compared to the fibrinolytic activity (FA) of the EFs measured on fibrin plates. There were significantly more patients with a low fibrinolytic response (FR) to stasis (difference between FA after and before stasis less than or equal to 0.3 TAU/ml) than controls (P less than 0.01). The electrophoretic-zymographic analysis revealed that: (i) in the resting state vascular plasminogen activator (v-PA) is always present in a form exhibiting a mol wt of 110 000 (complex of v-PA with its fast-acting antiactivator); (ii) a high FR to stasis (greater than 1.3 TAU/ml) is always associated with the presence of free v-PA (68 kdalton band); (iii) free v-PA is never detected when the FR is low; and (iv) a poor FR is generally (15 of 17 patients with low FR) associated with apparently complete inhibition of the released v-PA by the fast-acting antiactivator; in the two remaining patients in whom no broadening of the 110 kdalton band is observed, the release mechanism for v-PA is probably impaired.