scholarly journals Measurement of Different Forms of Tissue Plasminogen Activator in Plasma

2000 ◽  
Vol 46 (1) ◽  
pp. 38-46 ◽  
Author(s):  
Wayne L Chandler ◽  
Marcy L Jascur ◽  
Paul J Henderson
Keyword(s):  
Plasminogen Activator ◽  
Tissue Plasminogen Activator ◽  
Plasminogen Activator Inhibitor ◽  
C1 Inhibitor ◽  
Microtiter Plates ◽  
Tissue Plasminogen ◽  
Capture Antibody ◽  
The Individual ◽  
Activator Inhibitor Type ◽  
Pai 1

Abstract Background: We evaluated assays to measure both total tissue plasminogen activator (tPA) and the three principle forms of tPA in plasma: active tPA, tPA complexed with plasminogen activator inhibitor type 1 (PAI-1), and tPA complexed with C1-inhibitor. Methods: Active tPA was measured by use of an indirect amidolytic assay and immunofunctional assays. tPA/PAI-1, tPA/C1-inhibitor, and total tPA antigen were measured by use of microtiter plates coated with anti-tPA antibodies and, respectively, anti-PAI-1, anti-C1-inhibitor, and anti-tPA antibodies conjugated to peroxidase. Results: The immunofunctional tPA assay detected 1 U/L (0.001 U/mL) tPA and recovered 108% ± 12% of active tPA added to samples containing high (mean, 60 000 IU/L) PAI-1 activities vs a detection limit of 10 U/L (0.01 U/mL) and 13% ± 25% recovery for the indirect amidolytic tPA activity assay. For measurement of tPA/PAI-1 complex, polyclonal anti-PAI-1 conjugates recovered 112% ± 20% of the expected tPA/PAI-1 vs recovery of only 38% ± 16% when monoclonal anti-PAI-1 conjugates were used. Of three methods tested, two total tPA antigen assays correlated well (r2 = 0.85) and showed recoveries near 100%, whereas the third method showed lower correlations, higher intercepts, and falsely high recovery. A single anti-tPA capture antibody that performed the best in the individual assay evaluations was used to measure the different forms of tPA in 22 samples with a range of tPA and PAI-1 values. The sum of the molar concentrations of active tPA, tPA/PAI-1, and tPA/C1-inhibitor using the optimized methods was equal to 94% ± 7% of measured total tPA. Conclusion: Optimized assays based on a single anti-tPA capture antibody can be used to accurately measure the major forms of tPA in plasma.

Effect of PAI-1 levels on the molar concentrations of active tissue plasminogen activator (t-PA) and t-PA/PAI-1 complex in plasma

Blood ◽  
1990 ◽  
Vol 76 (5) ◽  
pp. 930-937 ◽  
Author(s):  
WL Chandler ◽  
SL Trimble ◽  
SC Loo ◽  
D Mornin
Keyword(s):  
Plasminogen Activator ◽  
Tissue Plasminogen Activator ◽  
Plasminogen Activator Inhibitor ◽  
Molar Ratio ◽  
Molar Activity ◽  
Activity Measurements ◽  
Tissue Plasminogen ◽  
Activator Inhibitor Type ◽  
Pai 1

We determined the in vivo molar concentrations of active tissue plasminogen activator (t-PA), active plasminogen activator inhibitor type 1 (PAI-1), and t-PA/PAI-1 complex. t-PA activity was measured in plasma stabilized by immediate acidification. PAI-1 activity and t- PA/PAI-1 complex antigen were measured in citrated plasma; these measurements were corrected for the loss in PAI-1 activity and increase in complex that occurs in unacidified plasma samples due to the continued reaction between t-PA and PAI-1 after the sample was drawn. To convert t-PA and PAI-1 activity measurements into molar concentrations we determined the specific molar activity of t-PA and PAI-1 in vivo: 4.48 x 10(13) IU/mol. Of 72 subjects studied, 13 had less than 150 pmol/L active PAI-1; in these individuals 33% +/- 21% of their t-PA was active and the molar ratio of active t-PA to active PAI- 1 was 0.20 +/- 0.13. In the 11 subjects with greater than 500 pmol/L active PAI-1, 1.5% = 1.1% of the t-PA was active and the molar ratio of active t-PA to active PAI-1 was 0.0043 +/- 0.0036. Overall, the fraction of active t-PA declined exponentially as a function of the active PAI-1 concentration. During the day, the percentage of total t- PA that was active increased from 12% at 8:00 AM to 31% at 8:00 PM, while the molar ratio of active t-PA to active PAI-1 increased from 0.05 to 0.22 from morning to evening (n = 12).

scholarly journals Effect of PAI-1 levels on the molar concentrations of active tissue plasminogen activator (t-PA) and t-PA/PAI-1 complex in plasma

Blood ◽  
1990 ◽  
Vol 76 (5) ◽  
pp. 930-937 ◽  
Author(s):  
WL Chandler ◽  
SL Trimble ◽  
SC Loo ◽  
D Mornin
Keyword(s):  
Plasminogen Activator ◽  
Tissue Plasminogen Activator ◽  
Plasminogen Activator Inhibitor ◽  
Molar Ratio ◽  
Molar Activity ◽  
Activity Measurements ◽  
Tissue Plasminogen ◽  
Activator Inhibitor Type ◽  
Pai 1

Abstract We determined the in vivo molar concentrations of active tissue plasminogen activator (t-PA), active plasminogen activator inhibitor type 1 (PAI-1), and t-PA/PAI-1 complex. t-PA activity was measured in plasma stabilized by immediate acidification. PAI-1 activity and t- PA/PAI-1 complex antigen were measured in citrated plasma; these measurements were corrected for the loss in PAI-1 activity and increase in complex that occurs in unacidified plasma samples due to the continued reaction between t-PA and PAI-1 after the sample was drawn. To convert t-PA and PAI-1 activity measurements into molar concentrations we determined the specific molar activity of t-PA and PAI-1 in vivo: 4.48 x 10(13) IU/mol. Of 72 subjects studied, 13 had less than 150 pmol/L active PAI-1; in these individuals 33% +/- 21% of their t-PA was active and the molar ratio of active t-PA to active PAI- 1 was 0.20 +/- 0.13. In the 11 subjects with greater than 500 pmol/L active PAI-1, 1.5% = 1.1% of the t-PA was active and the molar ratio of active t-PA to active PAI-1 was 0.0043 +/- 0.0036. Overall, the fraction of active t-PA declined exponentially as a function of the active PAI-1 concentration. During the day, the percentage of total t- PA that was active increased from 12% at 8:00 AM to 31% at 8:00 PM, while the molar ratio of active t-PA to active PAI-1 increased from 0.05 to 0.22 from morning to evening (n = 12).

A Kinetic Model of the Circulatory Regulation of Tissue Plasminogen Activator

1991 ◽  
Vol 66 (03) ◽  
pp. 321-328 ◽  
Author(s):  
Wayne L Chandler
Keyword(s):  
Plasminogen Activator ◽  
Tissue Plasminogen Activator ◽  
Active Form ◽  
Circadian Variation ◽  
Circulatory System ◽  
Hepatic Clearance ◽  
Plasminogen Activator Inhibitor ◽  
Tissue Plasminogen ◽  
Activator Inhibitor Type ◽  
Pai 1

SummaryA computer simulation was developed to study the regulation of active tissue plasminogen activator (t-PA) levels in plasma by kinetically modeling t-PA secretion, t-PA inhibition by plasminogen activator inhibitor type 1 (PAI-1), and hepatic clearance of t-PA, PAI-1 and t-PA/PAI-1 complex throughout a simplified human circulatory system. The model indicates that as the active PAI-1 concentration increases, the percent of t-PA in the active form decreases exponentially. Further, the reaction between t-PA and PAI-1 substantially reduces the half-lives of both active factors. By adjusting the t-PA and PAI-1 secretion rates to provide the best fit between simulated and measured circadian variations in t-PA, PAI-1 and complex, the model predicts that the diurnal rhythm in active t-PA levels is principally due to changes in the rate of PAI-1 secretion and not to variations in the t-PA secretion rate. In conclusion, the model predicts that PAI-1 is an important regulator of the concentration, half-life and circadian variation of active t-PA.

Herpes Simplex Virus Decreases Endothelial Cell Plasminogen Activator Inhibitor

1993 ◽  
Vol 69 (03) ◽  
pp. 253-258 ◽  
Author(s):  
Robert A Bok ◽  
Harry S Jacob ◽  
Jozsef Balla ◽  
Margaret Juckett ◽  
Theresa Stelle ◽  
...  
Keyword(s):  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Plasminogen Activator ◽  
Tissue Plasminogen Activator ◽  
Umbilical Vein ◽  
Plasminogen Activator Inhibitor ◽  
Tissue Plasminogen ◽  
Simplex Virus ◽  
Activator Inhibitor ◽  
Pai 1

SummaryHerpes simplex virus (HSV) infection is histopathologically associated with vascular injury, fibrinoid necrosis and inflammatory cell infiltrates. We have previously shown in vitro that HSV infection of human umbilical vein endothelial cells (HUVEC) promotes a procoagulant phenotype manifest by the induction of tissue factor, the loss of thrombomodulin, and an increase in platelet adhesion. In these studies we examined the effects of HSV infection on HUVEC plasminogen activator inhibitor type 1 (PAI-1) and tissue plasminogen activator (t-PA). HSV infection caused the loss of PAI-1 in the extracellular matrix (ECM) and that released into the supernatant of HUVEC. Both activity and antigen levels of the Serpin inhibitor are diminished as a result of HSV infection. The loss of inhibitor is not secondary to diminished vitronectin (Vn), the primary binding protein of PAI-1 in the ECM, but appears to be secondary to decreased synthesis at the RNA level. Tissue plasminogen activator (t-PA). synthesis is also decreased in endothelial HSV infection. PAI-1 loss may further promote a procoagulant phenotype in HSV infection in vivo.

scholarly journals The mechanism of the reaction between human plasminogen-activator inhibitor 1 and tissue plasminogen activator

1990 ◽  
Vol 265 (1) ◽  
pp. 109-113 ◽  
Author(s):  
T L Lindahl ◽  
P I Ohlsson ◽  
B Wiman
Keyword(s):  
Amino Acid ◽  
Plasminogen Activator ◽  
Tissue Plasminogen Activator ◽  
Plasminogen Activator Inhibitor ◽  
Peptide Bond ◽  
Plasminogen Activator Inhibitor 1 ◽  
Sds Page ◽  
Tissue Plasminogen ◽  
Activator Inhibitor ◽  
Pai 1

The structural events taking place during the reaction between PAI-1 (plasminogen-activator inhibitor 1) and the plasminogen activators sc-tPA (single-chain tissue plasminogen activator) and tc-tPA (two-chain tissue plasminogen activator) were studied. Complexes were formed by mixing sc-tPA or tc-tPA with PAI-1 in slight excess (on an activity basis). The complexes were purified from excess PAI-1 by affinity chromatography on fibrin-Sepharose. Examination of the purified complexes by SDS/polyacrylamide-gel electrophoresis (SDS/PAGE) and N-terminal amino acid sequence analysis demonstrated that a stoichiometric 1:1 complex is formed between PAI-1 and both forms of tPA. Data obtained from both complexes revealed the amino acid sequences of the parent molecules and, in addition, a new sequence: Met-Ala-Pro-Glu-Glu-. This sequence is found in the C-terminal portion of the intact PAI-1 molecule and thus locates the reactive centre of PAI-1 to Arg346-Met347. The proteolytic activity of sc-tPA is demonstrated by its capacity to cleave the ‘bait’ peptide bond in PAI-1. The complexes were inactive and dissociated slowly at physiological pH and ionic strength, but rapidly in aq. NH3 (0.1 mol/l). Amidolytic tPA activity was generated on dissociation of the complexes, corresponding to 0.4 mol of tPA/mol of complex. SDS/PAGE of the dissociated complexes indicated a small decrease in the molecular mass of PAI-1, in agreement with proteolytic cleavage of the ‘bait’ peptide bond during complex-formation.

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