Fibrinolytic activity in human atherosclerotic coronary arteries.

The localization of fibrinolytic areas in normal and atheromatous human coronary arteries was studied by the histochemical fibrin slide technique. Fibrinolytic activity was caused by a plasminogen activator. The activator, occasionally observed at sites in the normal endothelial lining, was abundantly present in relation to vessels in the normal adventitia. The pathological adventitia contained an increased number of active sites and endothelium covering an atherosclerotic plaque was richer in fibrinolytic sites than the normal endothelium. Within the vascularized plaque, fibrinolytically active capillaries could be traced from their origin in the vasa vasorum or, occasionally, in the endothelium. The results confirm and extend previous observations obtained in assays after extraction. They present patterns similar to those observed in normal tissue repair. ADDITIONAL