Acute psychological stress decreases plasma tissue plasminogen activator (tPA) and tissue plasminogen activator/plasminogen activator inhibitor-1 (tPA/PAI-1) complexes in cardiac patients

Tissue plasminogen activator (tPA) promotes fibrinolysis and impaired fibrinolysis is associated with atherosclerosis and thrombosis. Plasminogen activator inhibitor-1 (PAI-1) inhibits t-PA expression. The effects of acute laboratory stressors on tPA and tPA/PAI-1 complexes were assessed in a sample of 11 cardiac patients. Participants were randomly assigned to either a stress or relaxation condition at time 1, and the alternative condition at time 2. Blood samples were taken before (pre) and after (post) each session and participants completed a battery of psychological questionnaires. Two-way repeated-measures analysis of variance revealed a statistically significant decrease in tPA (P = 0.01) and tPA-PAI-1 complexes (P = 0.04) during the mental stress condition. Anger-in had a strong relationship to decreases in tPA/PAI-1 levels in the stress condition (r = 0.68, P < 0.05). Relaxation had no significant effect on tPA and tPA/PAI-1 levels. These data suggest that decreased fibrinolysis mediates the relationship between mental stress and atherosclerosis.