The ratio of plasminogen activator inhibitor type-1 activity to the concentration of plasminogen activator inhibitor type-1 protein in diabetes: adding insult to injury.

Abstract

This study was performed to delineate the relationship between plasminogen activator inhibitor type-1 (PAI-1) activity and PAI-1 protein to characterize the functional importance of elevated PAI-1 in diabetes. PAI-1 activity (chromogenic substrate kinetic assay) and protein (enzyme-linked immunosorbent assay) were assayed in baseline central venous catheter-acquired samples from 170 patients with type 2 diabetes studied in the Troglitazone Atherosclerosis Regression Trial (TART). The data demonstrated that the ratio of PAI-1 activity to the concentration of PAI-1 protein is increased as a function of increasing concentrations of PAI-1 protein in blood. The results demonstrate that the ratio of PAI-1 activity to the concentration of PAI-1 protein is higher when the concentration of PAI-1 is elevated. The nonlinearity appears to depend on the fact that the rate of disappearance of PAI-1 activity in blood is a function of the concentration of PAI-1 protein.