Fibrinolysis during normal human pregnancy: complex inter-relationships between plasma levels of tissue plasminogen activator and inhibitors and the euglobulin clot lysis time

SummaryThe relationships between tissue plasminogen activator (tPA), its fast acting inhibitor (PAI-1) and euglobulin clot lysis time (ELT) were investigated with healthy volunteers’ plasma. Turbidimetric clot lysis assay by the microtiter plate reader was utilized for ELT with a slight modification. Both tPA and PAI-1 showed the significant correlation with ELT. tPA had a significantly positive, not negative, correlation with ELT (R = 0.387, p <0.001). Higher correlation coefficients (R = 0.580, p <0.001 and R = 0.599, p <0.001) were obtained between ELT and total PAI-1 or free PAI-1 than tPA or tPA-PAI-1 complex (R = 0.427, p <0.001). The positive correlation was also obtained between tPA and PAI-1. These data suggest that PAI-1 is a highly important factor for ELT, especially, the amounts of free PAI-1 being the key factor to determine the ELT, which can represent the potential activity of the fibrinolytic system.

Download Full-text

PHYSICAL ACTIVITY RELEASES TISSUE PLASMINOGEN ACTIVATOR FROM EXERCISING PARTS OF BODY

10.1055/s-0038-1643117 ◽

1987 ◽

Author(s):

I Keber ◽

K Potisk ◽

D Keber ◽

M Stegnar ◽

N Vene

Keyword(s):

Physical Activity ◽

Plasminogen Activator ◽

Tissue Plasminogen Activator ◽

Fibrinolytic Activity ◽

Venous Occlusion ◽

Clot Lysis ◽

Lysis Time ◽

Tissue Plasminogen ◽

Euglobulin Clot Lysis Time ◽

The Difference

To determine the origin of tissue plasminogen activator (t-PA) release during physical activity, we studied the separate and combined effects of venous occlusion and acute physical activity on t-PA release in arm and leg. In 15 healthy volunteers 20 min venous occlusions of arm and leg were performed simultaneously before physical activity ( maximal stress testing on treadmill)(occlusion I), immediately after physical activity and 45 min later (occlusion II). Blood samples were drawn from unoccluded arm before occlusion and after physical activity, and from occluded arm and leg after occlusion. Fibrinolytic activity was measured by euglobulin clot lysis time (ECLT) and t-PA activity assay. The amount of released t-PA during different stimuli (fibrinolytic potential) was calculated as the difference between post- and prestimulation fibrinolytic activity. Before physical activity there was a great increase in fibrinolytic activity due to t-PA in the occluded arm but no increase in the occluded leg. Physical activity itself caused a similar increase of systemic fibrinolytic activity as arm occlusion locally. After physical activity arm occlusion evoked equally good response than before it. Fibrinolytic activity during leg occlusion behaved differently: there was an increase in t-PA activity in the occluded leg which persisted one hour after physical activity, when systemic fibrinolytic activity already fell to initial level.These results demonstrated that walking and running triggered t-PA release from the leg vessels. Since leg occlusion was not a stimulus for t-PA release, it served only as a method to demonstrate the effect of physical activity.

Download Full-text

Successful application of the tissue plasminogen activator (tPA)-induced clot lysis time (tCLT) in the evaluation of children with bleeding diatheses

Journal of Pediatric Hematology/Oncology ◽

10.1097/00043426-200007000-00050 ◽

2000 ◽

Vol 22 (4) ◽

pp. 374

Author(s):

G. Massey ◽

N. Dunn ◽

S. Carr ◽

J. Kuhn ◽

E. Russell ◽

...

Keyword(s):

Plasminogen Activator ◽

Tissue Plasminogen Activator ◽

Clot Lysis ◽

Lysis Time ◽

Tissue Plasminogen ◽

Clot Lysis Time

Download Full-text

Severe SARS-CoV-2 infection inhibits fibrinolysis leading to changes in viscoelastic properties of blood clot: A descriptive study of fibrinolysis

Thrombosis and Haemostasis ◽

10.1055/a-1400-6034 ◽

2021 ◽

Author(s):

Stefanie Hammer ◽

Helene Haeberle ◽

Christian Schlensak ◽

Michael Bitzer ◽

Nisar Malek ◽

...

Keyword(s):

Plasminogen Activator ◽

Tissue Plasminogen Activator ◽

Point Of Care ◽

Blood Clot ◽

Clot Lysis ◽

Plasminogen Activator Inhibitor 1 ◽

Blood Samples ◽

Lysis Time ◽

Tissue Plasminogen ◽

Pai 1

Background: Accumulating evidence indicates towards an association between SARS-CoV-2 infection and procoagulatory state in blood. Thromboelastographic investigations are useful point-of-care devices to assess coagulation and fibrinolysis. Objectives: We investigated the hypothesis that the procoagulatory state in COVID-19 patients is caused by impaired fibrinolysis system. Methods: COVID-19 patients admitted to normal wards or to the intensive care unit (ICU) were included in the study. Whole blood samples were investigated by thromboelastography. Additionally, global parameters of coagulation and factors of fibrinolysis as plasminogen activator inhibitor-1 (PAI-1), tissue plasminogen activator (tPA), plasminogen activity and alpha 2-antiplasmin (A2AP) were determined. Results and conclusion: A significantly increased lysis-resistance and a significantly longer time of lysis after adding tissue plasminogen activator was observed in blood samples from ICU COVID-19 patients compared to controls (maximal lysis: 3.25% ± 0.56 vs. 6.20% ± 0.89, p=0.0127; lysis time: 365.7s ± 44.6 vs. 193.2s ± 16.3, p=0.0014). PAI-1 activity was significantly higher in plasma samples of ICU COVID-19 patients (PAI-1: 4.92U/ml ± 0.91 vs. 1.28U/ml ± 0.33, p=0.001). Interestingly, a positively correlation between the activity of PAI-1 and the lysis time of the formed clot (r=0.7015, p=0.0006) was observed. Our data suggest that severe SARS-CoV-2 infection is associated with impaired fibrinolytic activity in blood, where fibrinolytic inhibitors are elevated leading to an increased resistance to clot lysis. Future clinical studies should address the contribution of the fibrinolysis system to the procoagulatory state in blood of COVID-19 patients and investigate potential therapeutic targets in this system.

Download Full-text

The pathogenesis of accelerated fibrinolysis in liver cirrhosis: a critical role for tissue plasminogen activator inhibitor

Blood ◽

10.1182/blood.v69.5.1315.1315 ◽

1987 ◽

Vol 69 (5) ◽

pp. 1315-1319 ◽

Cited By ~ 86

Author(s):

SL Hersch ◽

T Kunelis ◽

RB Jr Francis

Keyword(s):

Liver Cirrhosis ◽

Plasminogen Activator ◽

Tissue Plasminogen Activator ◽

Fibrinolytic Activity ◽

Blood Clot ◽

Critical Role ◽

Plasminogen Activator Inhibitor ◽

Clot Lysis ◽

Lysis Time ◽

Tissue Plasminogen

Abstract The pathogenesis of accelerated fibrinolysis in liver cirrhosis was investigated by comparing the results of specific assays for tissue plasminogen activator (tpa) antigen, tpa activity, tpa inhibitor, and alpha-2 plasmin inhibitor (a2PI) in 12 patients with cirrhosis and markedly accelerated fibrinolysis (dilute whole blood clot lysis time (DWBCLT) less than two hours), in nine patients with cirrhosis and moderately accelerated fibrinolysis (DWBCLT two to four hours), and in nine patients with cirrhosis and normal fibrinolysis (DWBCLT greater than four hours). Mean tpa antigen was markedly increased in all three groups, but no correlation was observed between overall fibrinolytic activity as measured by the DWBCLT and the level of tpa antigen. In contrast, there was a significant correlation between overall fibrinolytic activity and tpa activity and an equally significant correlation between fibrinolytic activity and decreased tpa inhibition. Mean a2PI activity was significantly lower than normal in groups 1 and 2 but was normal in group 3. The pathogenesis of accelerated fibrinolysis in liver cirrhosis thus appears to depend critically on the capacity of plasma inhibitors to inhibit increased circulating tpa antigen. Reduced a2PI also appears to play a role.

Download Full-text

Fibrinolytic parameters, lipid status and lipoprotein(a) in ischemic stroke patients

Srpski arhiv za celokupno lekarstvo ◽

10.2298/sarh10s1012v ◽

2010 ◽

Vol 138 (suppl. 1) ◽

pp. 12-17 ◽

Cited By ~ 8

Author(s):

Biljana Vuckovic ◽

Mirjana Djeric ◽

Tatjana Ilic ◽

Visnja Canak ◽

Suncica Kojic-Damjanov ◽

...

Keyword(s):

Ischemic Stroke ◽

Plasminogen Activator ◽

Clot Lysis ◽

Stroke Patients ◽

Lipid Status ◽

Lysis Time ◽

Euglobulin Clot Lysis Time ◽

Fibrinolytic Parameters ◽

Pai 1 ◽

Clot Lysis Time

Introduction. Ischemic stroke is the third leading cause of mortality and morbidity in most countries in the world. Impaired fibrinolysis, as well as disordered lipid metabolism have been recognized as risk factors for this disease. Objective. To study some of fibrinolytic parameters, lipid status and lipoprotein(a) - Lp(a) in ischemic stroke patients in Serbia and to examine associations between Lp(a) and fibrinolytic parameters. Methods. Sixty ischemic stroke patients (case group, mean age 63.48?9.62 years) and 30 age and sex matched healthy controls (control group, mean age 60.2?7.96 years) were studied. Results. A significantly longer euglobulin clot lysis time (219.7?78,8 min. vs 183.5?58,22 min; p=0.005) and higher levels of plasminogen activator inhibitor-1 (PAI-1) (48.5?17.1 ng/ml vs 27.1?10.1 ng/ml; p=6.2?10-11), tissue-type plasminogen activator antigen (t-PA) (11.1?7.14 ng/ml vs 6,.0?3.66 ng/ml; p=5.2?10-5) and D-dimer (382.27?504.22ng/ml vs 116.12?88.81 ng/ml; p=0.0002) were found in cases compared to controls. There were no significant differences in fibrinogen levels (4.30?0.84 g/l vs 4.09?0.64 g/l; p=0.23) or plasminogen activity (92.67?11.37 % vs 96.87?9.48%; p=0.085). There was no significant difference in Lp(a) concentration between cases and controls (0.15?0.11 g/l vs 0.12?0.11 g/l; p=0.261). However, in the cases, but not in the controls, multivariate analysis of associations between fibrinolytic parameters and Lp(a) showed the highest correlation between t-PA and PAI-1, and the latent effect of Lp(a) on t-PA and PAI-1. Conclusions. Our results show that there are important differences in the characteristics of the fibrinolytic mechanism in ischemic stroke patients compared to healthy population. The major differences are prolonged euglobulin clot lysis time and elevated PAI-1 and t-PA antigen in ischemic stroke patients. In addition, Lp(a) appears to be involved in the inhibition of fibrinolysis in ischemic disease through a mechanism unrelated to its serum concentrations.

Download Full-text

The Increase of Leg Fibrinolytic Potential After Reduction of Hydrostatic Stimulus

Thrombosis and Haemostasis ◽

10.1055/s-0038-1665297 ◽

1983 ◽

Vol 50 (03) ◽

pp. 731-734 ◽

Cited By ~ 4

Author(s):

Dušan Keber

Keyword(s):

Plasminogen Activator ◽

Venous Occlusion ◽

Clot Lysis ◽

The Third ◽

Lysis Time ◽

Before And After ◽

Euglobulin Clot Lysis Time ◽

The Difference ◽

Fibrinolytic Potential ◽

Clot Lysis Time

SummaryEleven patients were studied sequentially from the beginning of recumbency due to trauma up to the complete mobilization. The first blood sampling was performed 12 hr to 4 days after injury, the second after 12 to 33 days of recumbency and the third after one or more months of mobilization. The blood was drawn each time before and after venous occlusion of the arm and the leg for 20 min. Fibrinolytic potential was calculated as the difference between post- and preocclusion values of plasminogen activator activity, measured with the euglobulin clot lysis time (ECLT) and on fibrin plates. The results showed that fibrinolytic potential of legs after the period of recumbency was approaching that of the arms, being ten times higher as measured with ECLT and five times higher as measured on fibrin plates in comparison with the period after mobilization. It was concluded that hydrostatic pressure was the main, if not the only factor responsible for the difference in the content of plasminogen activator in veins of arms and legs and their fibrinolytic potential.

Download Full-text

Substrate Composition and the Effect of ε-Aminocaproic Acid on Tissue Plasminogen Activator and Urokinase-induced Fibrinolysis

Thrombosis and Haemostasis ◽

10.1055/s-0038-1647701 ◽

1974 ◽

Vol 32 (02/03) ◽

pp. 306-324 ◽

Cited By ~ 5

Author(s):

Sixtus Thorsen ◽

Tage Astrup

Keyword(s):

Plasminogen Activator ◽

Tissue Plasminogen Activator ◽

Aminocaproic Acid ◽

Fibrin Clot ◽

Clot Lysis ◽

Substrate Composition ◽

Lysis Time ◽

Biphasic Effect ◽

Tissue Plasminogen ◽

Inhibition Curve

SummaryThe influence of variations in substrate composition on the biphasic pattern of inhibition by e-aminocaproic acid (EACA) of urokinase-induced fibrinolysis, first observed on bovine plasminogen-rich fibrin, was studied using a fibrin clot lysis time assay. Different species of fibrinogen and plasminogen or plasmin were used. Preparations of different degrees of purification were compared at varying concentrations. The behavior of urokinase was compared with that of a porcine tissue plasminogen activator. Variations in the conditions of the assay greatly influenced the results. The concentration of fibrinogen had a particularly marked influence. At increased fibrinogen concentrations the biphasic response of urokinase was enhanced and a weak biphasic effect was also produced by the tissue activator which usually yields a uniformly increasing inhibition curve. The phase of fibrinolysis enhancement produced by urokinase with genuine plasminogen substrates occurs at substrate concentrations and EACA levels present in patients treated with EACA. The observed variations may explain discordant findings reported by various investigators.

Download Full-text

Thrombomodulin in Human Plasma Contributes to Inhibit Fibrinolysis through Acceleration of Thrombin-dependent Activation of Plasma Procarboxypeptidase B

Thrombosis and Haemostasis ◽

10.1055/s-0037-1614994 ◽

1998 ◽

Vol 79 (02) ◽

pp. 371-377 ◽

Cited By ~ 43

Author(s):

Yoshitaka Hosaka ◽

Yasuo Takahashi ◽

Hidemi Ishii

Keyword(s):

Human Plasma ◽

Clot Lysis ◽

Direct Inhibition ◽

Carboxypeptidase B ◽

Lysis Time ◽

Tissue Plasminogen ◽

Dependent Inhibition ◽

Normal Human ◽

Clot Lysis Time

SummaryThrombomodulin (TM) expressed on endothelial cells binds thrombin and initiates anticoagulant pathways. Soluble functional proteolytic fragments of TM are also present in circulating plasma. Recently, it was reported that TM accelerated thrombin-dependent plasma procarboxypeptidase B (pro-pCPB) activation in a purified system and suggested that TM may inhibit fibrinolysis in crude plasma. The aim of present study was to evaluate any functional role of soluble TM fragments in plasma or purified TM added into plasma to the regulation of coagulation and fibrinolysis. Addition of rabbit TM (1-200 ng/ml) to plasma resulted in a concentration-dependent prolongation of urokinase (UK)- or tissue plasminogen activator (t-PA)-induced clot lysis time. The concentration of TM required for the inhibition of fibrinolysis was lower than that required for the inhibition of coagulation. Addition of anti-rabbit TM IgG or anti-human TM IgG into plasma reduced UK- or t-PA-induced clot lysis time without affecting clotting times, indicating that exogenous TM or soluble TM fragments in normal human plasma participated in regulation of fibrinolysis. Moreover, the TM-dependent inhibition of fibrinolysis was observed only in the presence of thrombin and blocked by addition of carboxypeptidase B inhibitors, but not mediated by protein C activation or direct inhibition of UK, t-PA or plasmin. Analysis of various substrates and inhibitors indicated that TM accelerated thrombin-dependent pro-pCPB activation in plasma. The present results indicate that TM, including soluble TM fragments in plasma, inhibit fibrinolysis via activation of pro-pCPB in plasma.

Download Full-text

SENSITIVE AND QUANTITATIVE ASSAYS OF FUNCTIONALLY ACTIVE PLASMINOGEN ACTIVATORS IN PLASMA

10.1055/s-0038-1644423 ◽

1987 ◽

Cited By ~ 1

Author(s):

M Mahmoud ◽

P J Gaffney

Keyword(s):

Venous Occlusion ◽

Clot Lysis ◽

Antibody Concentration ◽

Drug Induced ◽

Lysis Time ◽

Sensitivity Range ◽

Tissue Plasminogen ◽

Euglobulin Clot Lysis Time ◽

Fibrinolytic Potential ◽

Clot Lysis Time

A previously described (Mahmoud, M. and Gaffney, P.J., Thrombos.Haemostas. 53: 356-9, 1985) bioimmunoassay for tissue plasminogen activator (t-PA) has been modified in terms of catcher antibody concentration and conditions of incubation of various of the steps in this assay to achieve a sensitivity range of 5 - 500 x 10-3 iu/ml of t-PA. A similar assay has been developed for urokinase (UK) achieving a sensitivity range of 5500 x 10-4 lu/mi. The sensitive t-PA assay has been demonstrated to be a valuable replacement of the traditional euglobulin clot lysis time (ECLT) assay and has the added advantage of avoiding loss of t-PA during formation of a euglobulin fraction and of calibration in terms of an International Standard for t-PA. Using both these assays it has been demonstrated that the enhanced fibrinolytic activity observed following exercise is due to increased levels of t-PA while the level of UK in plasma remains unaltered. This was further confirmed by quenching experiments using specific antibodies to t-PA and UK. In contradiction to an earlier report from this laboratory, free t-PA (10 - 60 x 10-3 iu/ml) has been demonstrated in resting plasma, while the level or free UK activity was 50 - 100 x 10-3.These sensitive t-PA and UK assays suggest that physiological and drug induced (heparin fraction CY 222 from Laboratoire Choay, Paris, and SP54 from Benechemie, Munich) enhancement of fibrinolytic potential m the human circulation is mainly mediated by t-PA. Venous occlusion of matched groups of subjects with and without deep venous thrombosis (DVT) showed a wide variation in response m t-PA levels in each group and no change in u-PA levels. There was no difference between the DVT and non DVT groups and this suggests that the notion of the 'non-responder' being more prone to thrombosis needs re-examination. Further experimentation with these sensitive assays may help to elaborate whether the levels of UK in plasma play any role in the haemostatic balance m man.

Download Full-text