title: PAI-1 plays an important role in the expression of t-PA activity in the euglobulin clot lysis by controlling the concentration of free t-PA.
abstract: The antigen levels of tissue plasminogen activator (t-PA) and plasminogen activator inhibitor-1 (PAI-1) were assayed in the plasma and in the euglobulin fraction, and their contributions to the euglobulin clot lysis time (ECLT) and t-PA activity were analyzed. Total and free PAI-1 levels in both fractions showed significant positive correlation with ECLT (p less than 0.001), whereas t-PA antigen level did not have a high correlation coefficient with ECLT. t-PA activity showed significant negative correlation with ECLT (p less than 0.001) and positive correlation with free t-PA level (p less than 0.001), which was calculated by the ratio of the concentrations of t-PA-PAI-1 complex and the free PAI-1. Thus free t-PA seems to dissolve the euglobulin clot and its concentration seems to be controlled by the concentration of free PAI-1. These findings were confirmed by the analyses of the effects of C1-inactivator and antibody against t-PA to regular ECLT and kaolin activated ECLT, the latter of which was only inhibited by the addition of C1-inactivator whereas the former was inhibited by anti-t-PA antibody.
authors.affiliation: Department of Physiology, Hamamatsu University, School of Medicine, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Urano
authors.forename: K
authors.initials: K
authors.lastname: Sumiyoshi
authors.forename: M H
authors.initials: MH
authors.lastname: Pietraszek
authors.forename: Y
authors.initials: Y
authors.lastname: Takada
authors.forename: A
authors.initials: A
authors.lastname: Takada
mesh_terms: D000293:Adolescent; D000328:Adult; D003174:Complement C1 Inactivator Proteins / Q000302:isolation & purification; D005342:Fibrinolysis / Q000276:immunology*; D006801:Humans; D007140:Immunoglobulin Fab Fragments / Q000276:immunology; D007616:Kaolin; D008297:Male; D015849:Plasminogen Inactivators / Q000276:immunology*; D012712:Serum Globulins / Q000378:metabolism*; D010959:Tissue Plasminogen Activator / Q000097:blood* / Q000276:immunology; D014568:Urokinase-Type Plasminogen Activator / Q000276:immunology
chemical_list: D003174:Complement C1 Inactivator Proteins; D007140:Immunoglobulin Fab Fragments; D015849:Plasminogen Inactivators; D012712:Serum Globulins; D007616:Kaolin; D010959:Tissue Plasminogen Activator; D014568:Urokinase-Type Plasminogen Activator