Reduction in pO2 decreases the fibrinolytic potential of cultured bovine endothelial cells derived from pulmonary arteries and lung microvasculature

The effect of anoxia on the fibrinolytic potential of cultured endothelial cells derived from bovine pulmonary artery and bovine lung microvasculature was studied. Both cell types reacted with an increase in plasminogen activator inhibitor (PAI) activity and a decrease in the plasminogen activator (PA) activity in the media after incubation under anoxic conditions. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis followed by fibrin autography and reverse fibrin autography indicated that the change in fibrinolytic potential was due to an impaired release of PA and not an increase in the production of PAI. Although anoxia did not affect the viability of the cells as judged by 51Cr release, their metabolism was influenced, which is reflected by increases in the levels of lactate in cell lysates and media. Furthermore, the effect of short-term anoxia on PA and PAI could not be reversed by reoxygenation for 24 hours. The results are discussed in terms of helping to explain the tendency of reocclusion after successful thrombolytic therapy, the development of pulmonary hypertension, and the thrombotic tendency of areas with an impaired circulatory supply.