Effects of recombinant human activated protein C on the coagulation system: a study with rotational thromboelastometry

Abstract Background Major trauma is a leading cause of morbidity and mortality worldwide with hemorrhage accounting for 40% of deaths. Acute traumatic coagulopathy exacerbates bleeding, but controversy remains over the degree to which inhibition of procoagulant pathways (anticoagulation), fibrinogen loss, and fibrinolysis drive the pathologic process. Through a combination of experimental study in a murine model of trauma hemorrhage and human observation, the authors’ objective was to determine the predominant pathophysiology of acute traumatic coagulopathy. Methods First, a prospective cohort study of 300 trauma patients admitted to a single level 1 trauma center with blood samples collected on arrival was performed. Second, a murine model of acute traumatic coagulopathy with suppressed protein C activation via genetic mutation of thrombomodulin was used. In both studies, analysis for coagulation screen, activated protein C levels, and rotational thromboelastometry (ROTEM) was performed. Results In patients with acute traumatic coagulopathy, the authors have demonstrated elevated activated protein C levels with profound fibrinolytic activity and early depletion of fibrinogen. Procoagulant pathways were only minimally inhibited with preservation of capacity to generate thrombin. Compared to factors V and VIII, proteases that do not undergo activated protein C–mediated cleavage were reduced but maintained within normal levels. In transgenic mice with reduced capacity to activate protein C, both fibrinolysis and fibrinogen depletion were significantly attenuated. Other recognized drivers of coagulopathy were associated with less significant perturbations of coagulation. Conclusions Activated protein C–associated fibrinolysis and fibrinogenolysis, rather than inhibition of procoagulant pathways, predominate in acute traumatic coagulopathy. In combination, these findings suggest a central role for the protein C pathway in acute traumatic coagulopathy and provide new translational opportunities for management of major trauma hemorrhage.

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Activated protein C protects against ventilator-induced pulmonary capillary leak

AJP Lung Cellular and Molecular Physiology ◽

10.1152/ajplung.90555.2008 ◽

2009 ◽

Vol 296 (6) ◽

pp. L1002-L1011 ◽

Cited By ~ 29

Author(s):

James H. Finigan ◽

Adel Boueiz ◽

Emily Wilkinson ◽

Rachel Damico ◽

Jarrett Skirball ◽

...

Keyword(s):

Lung Injury ◽

Protein C ◽

Activated Protein C ◽

Coagulation System ◽

Blue Dye ◽

Specific Gene ◽

Capillary Leakage ◽

Endothelial Protein C Receptor ◽

Pulmonary Endothelium ◽

Pulmonary Capillary

The coagulation system is central to the pathophysiology of acute lung injury. We have previously demonstrated that the anticoagulant activated protein C (APC) prevents increased endothelial permeability in response to edemagenic agonists in endothelial cells and that this protection is dependent on the endothelial protein C receptor (EPCR). We currently investigate the effect of APC in a mouse model of ventilator-induced lung injury (VILI). C57BL/6J mice received spontaneous ventilation (control) or mechanical ventilation (MV) with high (HVT; 20 ml/kg) or low (LVT; 7 ml/kg) tidal volumes for 2 h and were pretreated with APC or vehicle via jugular vein 1 h before MV. In separate experiments, mice were ventilated for 4 h and received APC 30 and 150 min after starting MV. Indices of capillary leakage included bronchoalveolar lavage (BAL) total protein and Evans blue dye (EBD) assay. Changes in pulmonary EPCR protein and Rho-associated kinase (ROCK) were assessed using SDS-PAGE. Thrombin generation was measured via plasma thrombin-antithrombin complexes. HVT induced pulmonary capillary leakage, as evidenced by significant increases in BAL protein and EBD extravasation, without significantly increasing thrombin production. HVT also caused significant decreases in pulmonary, membrane-bound EPCR protein levels and increases in pulmonary ROCK-1. APC treatment significantly decreased pulmonary leakage induced by MV when given either before or after initiation of MV. Protection from capillary leakage was associated with restoration of EPCR protein expression and attenuation of ROCK-1 expression. In addition, mice overexpressing EPCR on the pulmonary endothelium were protected from HVT-mediated injury. Finally, gene microarray analysis demonstrated that APC significantly altered the expression of genes relevant to vascular permeability at the ontology (e.g., blood vessel development) and specific gene (e.g., MAPK-associated kinase 2 and integrin-β6) levels. These findings indicate that APC is barrier-protective in VILI and that EPCR is a critical participant in APC-mediated protection.

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Protein C, an antithrombotic protein, is reduced in hospitalized patients with intravascular coagulation

Blood ◽

10.1182/blood.v60.1.261.261 ◽

1982 ◽

Vol 60 (1) ◽

pp. 261-264 ◽

Cited By ~ 121

Author(s):

JH Griffin ◽

DF Mosher ◽

TS Zimmerman ◽

AJ Kleiss

Keyword(s):

Liver Disease ◽

Serine Protease ◽

Vitamin K ◽

Protein C ◽

Activated Protein C ◽

Coagulation System ◽

Antigen Concentration ◽

Intravascular Coagulation ◽

The Mean

Abstract Activated protein C is a potent anticoagulant and profibrinolytic enzyme that can be derived from the vitamin-K-dependent serine protease zymogen, protein C, by the action of thrombin. Protein C antigen concentration was determined in plasmas from normals (n = 40) and from 38 patients with intravascular coagulation as evidenced by positive FDP (greater than micrograms/ml). Plasma protein C was 4 micrograms/ml in normals and was significantly depressed (less than 2 SD below the mean of normals) in 19 of the 38 patients. Of 15 patients with suspected intravascular coagulation but normal FDP, protein C was decreased in 5 individuals; 3 of these 5 patients had liver disease. Based on these results, we suggest that extensive activation of the coagulation system in vivo causes a significant consumption of protein C, presumably due to its activation by thrombin and subsequent clearance.

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Activation of the Coagulation System Should Be Considered in the Initial Phase of Chemotherapy in Acute Myeloid Leukemia.

Blood ◽

10.1182/blood.v104.11.1039.1039 ◽

2004 ◽

Vol 104 (11) ◽

pp. 1039-1039

Author(s):

Jan Astermark ◽

Karin Strandberg ◽

Bengt Sallerfors ◽

Johan Stenflo ◽

Erik Berntorp

Keyword(s):

Acute Myeloid Leukemia ◽

Factor Viii ◽

Initial Phase ◽

Myeloid Leukemia ◽

Protein C ◽

Thrombin Generation ◽

Activated Protein C ◽

Coagulation System ◽

Viii Level ◽

Acute Myeloid

Abstract Malignant hematologic disorders may be associated with coagulopathy causing bleeding or thromboembolic complications. Severe infections as well as chemotherapy may augment this risk by the action of inflammatory mediators and the release of proteases. We evaluated the hemostatic process in 10 patients with acute myeloid leukemia (no acute promyelocytic leukemia) before the start of induction therapy with IDA-C and daily during the following two weeks of treatment. Various hemostatic parameters were studied, including the complex between activated protein C and the protein C inhibitor (APC-PCI) with a newly developed method, thrombin generation, protein C, prothrombin fragment 1+2 (F1+2), antithrombin and factor VIII. The APC-PCI concentration was relatively high in all patients at start of treatment (mean 0.81 ± SEM 0.27 μg/L; normal range 0.07–0.26 μg/L) reflecting an activation of the coagulation system, and further increased during the initial phase of chemotherapy reaching the highest level on Day 3 to 5 of 1.67±0.53 μg/L (p=0.0047). The concentration of the complex then declined during the following 10 days to 0.10±0.03 μg/L on Day 14, i.e. to a concentration significantly lower than that at start of treatment (p=0.005). The concentration of F1+2 varied in a similar way with a concentration of 2.17±0.51 nM at start of treatment and an increase on Day 3–5 to 4.17±0.93 nM (p=0.005) followed by a decline to 1.09±0.22 nM on Day 14. Thrombin generation was relatively high in the initial phase of chemotherapy (319.0±44.5 nM) and then declined to 154.6±17.2 nM on Day 14 (p=0.008). The protein C activity was relatively low at start (0.70±0.05 IU/mL) indicating a state of consumption, but showed a trend towards normalization during treatment reaching an average level of 0.78±0.05 IU/mL for all patients on Day 14 (p=0.103). The factor VIII level was high and relatively stable during the two weeks of treatment with a range of 1.73±0.16 to 1.89±0.17 IU/mL, indicating a reactive state. The level of antithrombin was normal at start of treatment (1.00±0.05 IU/mL) and throughout the study period. Our data show that acute myeloid leukemia may be associated with a significant coagulopathy and that the activity in the coagulation process is increased during the initial phase of chemotherapy. This should be considered in patients at start of treatment, in particular, in patients with septicemia and/or signs of disseminated intravascular coagulation.

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Neuroprotection by Recombinant Thrombomodulin

Thrombosis and Haemostasis ◽

10.1055/s-0037-1613837 ◽

2000 ◽

Vol 83 (03) ◽

pp. 462-468 ◽

Cited By ~ 17

Author(s):

Yuji Taoka ◽

Mitsuhiro Uchiba ◽

Masayoshi Johno ◽

Kenji Okajima

Keyword(s):

Spinal Cord ◽

Spinal Cord Injury ◽

Protein C ◽

Activated Protein C ◽

Coagulation System ◽

Therapeutic Effects ◽

Soluble Thrombomodulin ◽

Tnf Α ◽

Cord Injury ◽

Motor Disturbances

SummaryWe examined whether recombinant human soluble thrombomodulin (rhs-TM) reduces compression trauma-induced spinal cord injury through protein C activation in rats. Administration of rhs-TM, either before or after the induction of spinal cord injury (SCI), markedly reduced the resulting motor disturbances. However, neither rhs-TM pretreated with an anti-rhs-TM monoclonal antibody (MAb) F2H5, which inhibits thrombin binding to rhs-TM, nor those pretreated with MAb R5G12, which selectively inhibits protein C activation by rhsTM, prevented the motor disturbances. Intramedullary hemorrhages, observed 24 h after trauma, were significantly reduced in animals given rhs-TM. The increase in the tissue levels of tumor necrosis factor-α (TNF-α), TNF-α mRNA expression, and the accumulation of leukocytes in the damaged segment of the spinal cord were significantly inhibited in animals receiving rhs-TM, but these effects were not observed following administration of rhs-TM pretreated with MAb R5G12 or MAb F2H5. Leukocytopenia and activated protein C all produced effects similar to those of rhs-TM.These findings suggest that rhs-TM prevents compression traumainduced SCI by inhibiting leukocyte accumulation by reducing the expression of TNF-α mRNA and such therapeutic effects of rhs-TM could be dependent on its protein C activation capacity. Findings further suggest that thrombomodulin can be implicated not only in the coagulation system but in regulation of the inflammatory response.

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A Novel Thrombomodulin Gene Mutation in a Patient Suffering from Sagittal Sinus Thrombosis

Thrombosis and Haemostasis ◽

10.1055/s-0038-1657708 ◽

1997 ◽

Vol 78 (04) ◽

pp. 1164-1166 ◽

Cited By ~ 31

Author(s):

Lena Norlund ◽

Bengt Zöller ◽

Ann-Kristin Öhlin

Keyword(s):

Protein C ◽

Sinus Thrombosis ◽

Activated Protein C ◽

Protein S ◽

Thromboembolic Disease ◽

Coagulation System ◽

Sagittal Sinus ◽

Apc Resistance ◽

American Patient ◽

Sagittal Sinus Thrombosis

SummaryThrombomodulin is an endothelial cell membrane glycoprotein that promotes protein C activation. It has been clearly demonstrated that the anticoagulant functions of the protein C system are important in the prevention of thromboembolic disease. Patients with protein C or protein S deficiency and/or resistance to activated protein C (APC resistance) are at higher risk for developing thromboembolic disease. The first mutation in the thrombomodulin gene was discovered in an American patient suffering from pulmonary embolism at the age of 45 (Öhlin and Marlar 1995). Here we report a case of sagittal sinus thrombosis in a 42-year-old Swedish woman. She was found to carry a heterozygous point mutation changing G127 to A, predicting an Ala25 to a Thr change in the mature thrombomodulin protein. This mutation was also found in her 16-year-old daughter, who so far has not suffered from any thrombotic events. The patient had no other detectable prothrombotic genetic defects associated with the coagulation system. This case supports the hypothesis of an association between mutations in the thrombomodulin gene and venous thrombosis.

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Protein C, an antithrombotic protein, is reduced in hospitalized patients with intravascular coagulation

Blood ◽

10.1182/blood.v60.1.261.bloodjournal601261 ◽

1982 ◽

Vol 60 (1) ◽

pp. 261-264 ◽

Cited By ~ 4

Author(s):

JH Griffin ◽

DF Mosher ◽

TS Zimmerman ◽

AJ Kleiss

Keyword(s):

Liver Disease ◽

Serine Protease ◽

Vitamin K ◽

Protein C ◽

Activated Protein C ◽

Coagulation System ◽

Antigen Concentration ◽

Intravascular Coagulation ◽

The Mean

Activated protein C is a potent anticoagulant and profibrinolytic enzyme that can be derived from the vitamin-K-dependent serine protease zymogen, protein C, by the action of thrombin. Protein C antigen concentration was determined in plasmas from normals (n = 40) and from 38 patients with intravascular coagulation as evidenced by positive FDP (greater than micrograms/ml). Plasma protein C was 4 micrograms/ml in normals and was significantly depressed (less than 2 SD below the mean of normals) in 19 of the 38 patients. Of 15 patients with suspected intravascular coagulation but normal FDP, protein C was decreased in 5 individuals; 3 of these 5 patients had liver disease. Based on these results, we suggest that extensive activation of the coagulation system in vivo causes a significant consumption of protein C, presumably due to its activation by thrombin and subsequent clearance.

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