scholarly journals Alteration of fibrin network by activated protein C

Blood ◽  
1994 ◽  
Vol 83 (9) ◽  
pp. 2541-2548
Author(s):  
A Gruber ◽  
E Mori ◽  
GJ del Zoppo ◽  
L Waxman ◽  
JH Griffin
Keyword(s):  
Protein C ◽  
Degradation Products ◽  
Activated Protein C ◽  
Relative Number ◽  
Relative Mass ◽  
Clot Lysis ◽  
Fibrin Degradation Products ◽  
Rate Of Increase ◽  
Fibrin Network

The antithrombotic plasma enzyme, activated protein C (APC), may play a role in thrombolysis. In vitro, acceleration of clot lysis by APC depends on its ability to inhibit the activation of prothrombin. The effect of APC on the assembly and dispersion of fibrin network was studied using turbidimetry, plasmin digestion of fibrin, and electron microscopy of plasma clots. The addition of APC before clotting but not after clotting accelerated clot lysis. The rate of increase in the turbidity of clotting plasma was reduced by APC. The turbidity of plasma clots containing APC was directly related to the clot lysis time. Fibrin from plasma clots that were formed in the presence of APC yielded less fibrin degradation products than fibrin from clots without added APC. Furthermore, APC reduced the diameter and relative number of fibrin fibers in plasma clots during gel assembly. We propose that APC may enhance the efficacy of thrombolysis by reducing the relative mass of fibrin within maturing thrombi.

scholarly journals Alteration of fibrin network by activated protein C

Blood ◽  
1994 ◽  
Vol 83 (9) ◽  
pp. 2541-2548 ◽  
Author(s):  
A Gruber ◽  
E Mori ◽  
GJ del Zoppo ◽  
L Waxman ◽  
JH Griffin
Keyword(s):  
Protein C ◽  
Degradation Products ◽  
Activated Protein C ◽  
Relative Number ◽  
Relative Mass ◽  
Clot Lysis ◽  
Fibrin Degradation Products ◽  
Rate Of Increase ◽  
Fibrin Network

Abstract The antithrombotic plasma enzyme, activated protein C (APC), may play a role in thrombolysis. In vitro, acceleration of clot lysis by APC depends on its ability to inhibit the activation of prothrombin. The effect of APC on the assembly and dispersion of fibrin network was studied using turbidimetry, plasmin digestion of fibrin, and electron microscopy of plasma clots. The addition of APC before clotting but not after clotting accelerated clot lysis. The rate of increase in the turbidity of clotting plasma was reduced by APC. The turbidity of plasma clots containing APC was directly related to the clot lysis time. Fibrin from plasma clots that were formed in the presence of APC yielded less fibrin degradation products than fibrin from clots without added APC. Furthermore, APC reduced the diameter and relative number of fibrin fibers in plasma clots during gel assembly. We propose that APC may enhance the efficacy of thrombolysis by reducing the relative mass of fibrin within maturing thrombi.

scholarly journals The cofactor role of protein S in the acceleration of whole blood clot lysis by activated protein C in vitro

Blood ◽  
1986 ◽  
Vol 67 (4) ◽  
pp. 1189-1192 ◽  
Author(s):  
NJ de Fouw ◽  
F Haverkate ◽  
RM Bertina ◽  
J Koopman ◽  
A van Wijngaarden ◽  
...  
Keyword(s):  
Whole Blood ◽  
Protein C ◽  
Degradation Products ◽  
Blood Clot ◽  
Activated Protein C ◽  
Protein S ◽  
Tissue Type ◽  
Clot Lysis ◽  
Fibrin Degradation Products

Abstract The effect of purified human activated protein C (APC) and protein S on fibrinolysis was studied by using an in vitro blood clot lysis technique. Blood clots were formed from citrated blood (supplemented with 125I-fibrinogen) by adding thrombin and Ca2+-ions; lysis of the clots was achieved by adding tissue-type plasminogen activator. The release of labeled fibrin degradation products from the clots into the supernatant was followed in time. We clearly demonstrated that APC accelerates whole blood clot lysis in vitro. The effect of APC was completely quenched by antiprotein C IgG, pretreatment of APC with diisopropylfluorophosphate, and preincubation of the blood with antiprotein S IgG. This demonstrates that both the active site of APC and the presence of the cofactor, protein S, are essential for the expression of the profibrinolytic properties. At present, the substrate of APC involved in the regulation of fibrinolysis is not yet known. Analysis of the radiolabeled fibrin degradation products demonstrated that APC had no effect on the fibrin cross-linking capacity of factor XIII.

scholarly journals The cofactor role of protein S in the acceleration of whole blood clot lysis by activated protein C in vitro

Blood ◽  
1986 ◽  
Vol 67 (4) ◽  
pp. 1189-1192
Author(s):  
NJ de Fouw ◽  
F Haverkate ◽  
RM Bertina ◽  
J Koopman ◽  
A van Wijngaarden ◽  
...  
Keyword(s):  
Whole Blood ◽  
Protein C ◽  
Degradation Products ◽  
Blood Clot ◽  
Activated Protein C ◽  
Protein S ◽  
Tissue Type ◽  
Clot Lysis ◽  
Fibrin Degradation Products

The effect of purified human activated protein C (APC) and protein S on fibrinolysis was studied by using an in vitro blood clot lysis technique. Blood clots were formed from citrated blood (supplemented with 125I-fibrinogen) by adding thrombin and Ca2+-ions; lysis of the clots was achieved by adding tissue-type plasminogen activator. The release of labeled fibrin degradation products from the clots into the supernatant was followed in time. We clearly demonstrated that APC accelerates whole blood clot lysis in vitro. The effect of APC was completely quenched by antiprotein C IgG, pretreatment of APC with diisopropylfluorophosphate, and preincubation of the blood with antiprotein S IgG. This demonstrates that both the active site of APC and the presence of the cofactor, protein S, are essential for the expression of the profibrinolytic properties. At present, the substrate of APC involved in the regulation of fibrinolysis is not yet known. Analysis of the radiolabeled fibrin degradation products demonstrated that APC had no effect on the fibrin cross-linking capacity of factor XIII.

scholarly journals Evidence of activation of the protein C pathway during acute vascular damage induced by Mediterranean spotted fever

Blood ◽  
1991 ◽  
Vol 78 (2) ◽  
pp. 416-422
Author(s):  
V Vicente ◽  
F Espana ◽  
D Tabernero ◽  
A Estelles ◽  
J Aznar ◽  
...  
Keyword(s):  
Protein C ◽  
Degradation Products ◽  
Spotted Fever ◽  
Activated Protein C ◽  
Quantitative Information ◽  
Endothelial Damage ◽  
Mediterranean Spotted Fever ◽  
Fibrin Degradation Products ◽  
Alpha 1 Antitrypsin

Mediterranean spotted fever (MSF) is a rickettsiosis that induces widespread microvascular injury. To obtain quantitative information on the in vivo activation and inactivation of the protein C system during the acute phase of endothelial damage, several components of the protein C pathway were studied in 28 MSF patients. Upon admission (day 1), patients showed clear evidence of endothelial damage as reflected by the significant decrease in the ratio VIII:C/vWF:Ag (0.36 +/- 0.14, mean +/- SD) compared with normals (0.98 +/- 0.14), and clinical and laboratory signs of hemostatic alterations such as decreased platelet count, positive fibrinogen/fibrin degradation products, and increased thrombin:antithrombin-III complex levels. Antigenic protein C (72% +/- 18%) and protein C inhibitor (PCI) (41% +/- 20%) were significantly decreased (P less than .001). Complexes of activated protein C (APC) with PCI or with alpha 1-antitrypsin (alpha 1AT) and of plasma kallikrein with PCI (KK:PCI) were measured using sandwich enzyme-linked immunosorbent assays. APC:alpha 1AT complex levels were increased in patients at day 1 (27 +/- 13 ng/mL) compared with controls (7 +/- 2 ng/mL), and APC:PCI and KK:PCI complexes, which were not detectable in any of the controls, were present in 57% and 75% of the 28 MSF patients, with mean levels of 11 +/- 5 and 46 +/- 16 ng/mL, respectively. After remission of the disease (day 30), a trend toward normal values in the majority of the parameters studied was found. This study shows that, in the course of endothelial injury, MSF patients experience a generalized activation of the protein C pathway, resulting in consumption of protein C and PCI, and in the appearance of APC:inhibitor complexes. Moreover, these data provide the evidence that KK:PCI circulating complexes occur in vivo.

scholarly journals Evidence of activation of the protein C pathway during acute vascular damage induced by Mediterranean spotted fever

Blood ◽  
1991 ◽  
Vol 78 (2) ◽  
pp. 416-422 ◽  
Author(s):  
V Vicente ◽  
F Espana ◽  
D Tabernero ◽  
A Estelles ◽  
J Aznar ◽  
...  
Keyword(s):  
Protein C ◽  
Degradation Products ◽  
Spotted Fever ◽  
Activated Protein C ◽  
Quantitative Information ◽  
Endothelial Damage ◽  
Mediterranean Spotted Fever ◽  
Fibrin Degradation Products ◽  
Alpha 1 Antitrypsin

Abstract Mediterranean spotted fever (MSF) is a rickettsiosis that induces widespread microvascular injury. To obtain quantitative information on the in vivo activation and inactivation of the protein C system during the acute phase of endothelial damage, several components of the protein C pathway were studied in 28 MSF patients. Upon admission (day 1), patients showed clear evidence of endothelial damage as reflected by the significant decrease in the ratio VIII:C/vWF:Ag (0.36 +/- 0.14, mean +/- SD) compared with normals (0.98 +/- 0.14), and clinical and laboratory signs of hemostatic alterations such as decreased platelet count, positive fibrinogen/fibrin degradation products, and increased thrombin:antithrombin-III complex levels. Antigenic protein C (72% +/- 18%) and protein C inhibitor (PCI) (41% +/- 20%) were significantly decreased (P less than .001). Complexes of activated protein C (APC) with PCI or with alpha 1-antitrypsin (alpha 1AT) and of plasma kallikrein with PCI (KK:PCI) were measured using sandwich enzyme-linked immunosorbent assays. APC:alpha 1AT complex levels were increased in patients at day 1 (27 +/- 13 ng/mL) compared with controls (7 +/- 2 ng/mL), and APC:PCI and KK:PCI complexes, which were not detectable in any of the controls, were present in 57% and 75% of the 28 MSF patients, with mean levels of 11 +/- 5 and 46 +/- 16 ng/mL, respectively. After remission of the disease (day 30), a trend toward normal values in the majority of the parameters studied was found. This study shows that, in the course of endothelial injury, MSF patients experience a generalized activation of the protein C pathway, resulting in consumption of protein C and PCI, and in the appearance of APC:inhibitor complexes. Moreover, these data provide the evidence that KK:PCI circulating complexes occur in vivo.

Whole blood clot lysis: In vitro modulation by activated protein C

1985 ◽  
Vol 37 (6) ◽  
pp. 639-649 ◽  
Author(s):  
Fletcher B. Taylor ◽  
Marion S. Lockhart
Keyword(s):  
Whole Blood ◽  
Protein C ◽  
Blood Clot ◽  
Activated Protein C ◽  
Clot Lysis

Endothelial cell protein C receptor plays an important role in protein C activation in vivo

Blood ◽  
2001 ◽  
Vol 97 (6) ◽  
pp. 1685-1688 ◽  
Author(s):  
Fletcher B. Taylor ◽  
Glenn T. Peer ◽  
Marion S. Lockhart ◽  
Gary Ferrell ◽  
Charles T. Esmon
Keyword(s):  
Monoclonal Antibody ◽  
Endothelial Cell ◽  
Protein C ◽  
Degradation Products ◽  
Activated Protein C ◽  
Vital Signs ◽  
Cell Protein ◽  
Increased Risk

Endothelial cell protein C receptor (EPCR) augments protein C activation by the thrombin-thrombomodulin complex about 5-fold in vitro. Augmentation is EPCR concentration dependent even when the EPCR concentration is in excess of the thrombomodulin. EPCR is expressed preferentially on large blood vessel endothelium, raising questions about the importance of protein C-EPCR interaction for augmenting systemic protein C activation. In these studies, this question was addressed directly by infusing thrombin into baboons in the presence or absence of a monoclonal antibody to EPCR that blocks protein C binding. Activated protein C levels were then measured directly by capturing the enzyme on a monoclonal antibody and assaying with chromogenic substrate. Blocking protein C-EPCR interaction resulted in about an 88% decrease in circulating activated protein C levels generated in response to thrombin infusion. Leukocyte changes, fibrinogen consumption, fibrin degradation products, and vital signs were similar between the animals infused with thrombin alone and those infused with thrombin and the anti-EPCR antibody. The results indicate that EPCR plays a major role in protein C activation and suggest that defects in the EPCR gene might contribute to increased risk of thrombosis.

scholarly journals 3K3A-Activated Protein C Variant Does Not Interfere With the Plasma Clot Lysis Activity of Tenecteplase

Stroke ◽  
2020 ◽  
Vol 51 (7) ◽  
pp. 2236-2239
Author(s):  
Purba Mukherjee ◽  
Patrick Lyden ◽  
José A. Fernández ◽  
Thomas P. Davis ◽  
Kent E. Pryor ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Protein C ◽  
Activated Protein C ◽  
In Vitro Study ◽  
Tissue Type ◽  
Clot Lysis ◽  
Bolus Administration ◽  
Plasma Clot ◽  
Lysis Activity

Background and Purpose: A recombinant engineered variant of APC (activated protein C), 3K3A-APC, lacks anticoagulant properties (<10%) while preserving APCs anti-inflammatory, anti-apoptotic, and neuroprotective functions and is very promising in clinical trials for ischemic stroke. Therapeutic intervention with single bolus administration of the third-generation tPA (tissue-type plasminogen activator), tenecteplase, is anticipated to be widely adopted for treatment of acute ischemic stroke. 3K3A-APC is well-tolerated in stroke patients dosed with alteplase, and in vitro studies show 3K3A-APC does not interfere with alteplase-induced clot lysis. The purpose of this in vitro study was to assess the influence of 3K3A-APC on tenecteplase-induced clot lysis. Methods: Tenecteplase-mediated lysis of thrombin generated plasma clots of human normal pooled plasma was monitored in the presence of varying doses of 3K3A-APC. The effects on fibrinolysis by tenecteplase and alteplase were compared. Results: The presence of 3K3A-APC shortened the time for clot lysis induced by tenecteplase at very low levels but not at higher therapeutic concentrations of tenecteplase. Comparisons of alteplase-mediated clot lysis to tenecteplase clot lysis showed that both thrombolytic agents behaved similarly in the presence of 3K3A-APC. Conclusions: These results indicate that 3K3A-APC does not interfere with tenecteplase’s clot lysis function.

Fibrinogen/Fibrin Degradation Products in Defibrination Syndrome Analysed on the Basis of Molecular Weight on Gel Exclusion Chromatography

1975 ◽  
Author(s):  
M. Kazama ◽  
T. Abe
Keyword(s):  
Molecular Weight ◽  
Degradation Products ◽  
Fibrin Clot ◽  
Clot Lysis ◽  
Elution Profile ◽  
Fibrin Degradation Products ◽  
Exclusion Chromatography ◽  
D Antigen ◽  
Stabilized Fibrin

1) Fresh citrated plasmas of cases of defibrination syndrome were chromatographed on Biogel A-5 m column, which revealed a two-peaked elution profile of fibrinogen-related antigen with reproducibility. The first peak was eluted at the Vo of the column and the second one at Ve of the early FDP. It was found in the preliminary experiments in vitro, that the big molecular FDP was formed exclusively in the process of fibrin clot lysis, irrespective if it was non-stabilized or stabilized.2) FDP in thesen patients’ serums, after thorough digestion with plasmin, were chromatographed on Sephadex G200 column. A reproducible elution profile of FDP-D antigen revealed single peak, of which Ve was corresponded with that of FDP-D monomer derived from fibrinogen or non-stabilized fibrin.It was postulated that the FDP in plasmas of defibrination syndrome were mainly originated from the fibrinogen or non-stabilized fibrin formed in the process of the diseases.

scholarly journals Pharmacological Differentiation of Thrombomodulin Alfa and Activated Protein C on Coagulation and Fibrinolysis In Vitro

2018 ◽  
Vol 24 (6) ◽  
pp. 859-866 ◽  
Author(s):  
Kosuke Tanaka ◽  
Shunsuke Tawara ◽  
Kazuhisa Tsuruta ◽  
Debra Hoppensteadt ◽  
Jawed Fareed
Keyword(s):  
Protein C ◽  
Activated Protein C ◽  
Bleeding Risk ◽  
Clot Lysis ◽  
Clotting Time ◽  
Soluble Thrombomodulin ◽  
Activated Clotting Time ◽  
Lysis Time ◽  
Clot Lysis Time

Although thrombomodulin alfa (TM alfa), recombinant human soluble thrombomodulin, exerts antithrombogenic effects through activated protein C (APC), clinical trials suggested that TM alfa has a lower bleeding risk than does recombinant human APC. To address the mechanism explaining this difference, effects of TM alfa and APC on thrombogenic, coagulation, and fibrinolytic processes were compared in vitro. TM alfa and APC inhibited generation of thrombogenic markers, thrombin, and prothrombin fragment F1+2 and prolonged coagulation parameters, activated clotting time (ACT), and activated partial thromboplastin time (APTT). Concentrations of TM alfa effective for thrombin and F1+2 generation inhibition were comparable to those of APC. However, effects of TM alfa on ACT and APTT were clearly weaker than those of APC. TM alfa significantly prolonged clot lysis time (CLT) and decreased LY30, a parameter of degree of fibrinolysis in thromboelastography, whereas APC significantly shortened CLT and increased LY30. These results suggested that while the antithrombogenic effects of TM alfa were similar to those of APC, its anticoagulant effects were lower. In addition, effects of TM alfa were antifibrinolytic, while those of APC were profibrinolytic.

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