A 59-year-old man experiences acute chest pain and is rushed to the emergency room. Laboratory studies and ECG demonstrate an acute myocardial infarction; however, coronary artery angiography performed 2 hours later does not show evidence of thrombosis. Intravascular thrombolysis that occurred in this patient was mediated by plasminogen activators that were released by which of the following cells?

Endothelial cells. The vascular endothelium has the ability to promote or inhibit tissue perfusion and inflammatory cell influx through multiple mechanisms. For example, endothelial cells in the vicinity of the thrombus produce tissue-type plasminogen activators, which activate plasmin and initiate thrombolysis (fibrinolysis). None of the other cells produce significant quantities of plasminogen activators.Diagnosis: Myocardial infarction, hemostasis