Increase in plasma concentration of plasminogen activator inhibitor, fibrinogen, von Willebrand factor, factor VIII:C and in erythrocyte sedimentation rate with age.

Elderly patients have previously been shown to have an increased plasma concentration of tissue plasminogen activator (t-PA) antigen (t-PA Ag). Since the concentration of t-PA Ag depends on both free t-PA and t-PA complexed with inhibitors, mainly plasminogen activator inhibitor (PA inhibitor), we have investigated the relationship between the plasma concentration of PA inhibitor and age in 20 elderly and 20 young individuals. Elderly individuals showed a slight increase in PA inhibitor, in parallel with increase on others, acute-phase proteins, fibrinogen, von Willebrand factor, factor VIII:C, and the erythrocyte sedimentation rate. The increase in PA inhibitor as well as other acute-phase proteins in the elderly may be significant in relation to the increased incidence of thrombotic disease.