scholarly journals Tissue Factor in the Myocardium: Evidence of Roles in Haemostasis and Inflammation

2004 ◽  
Vol 20 (6) ◽  
pp. 353-358 ◽  
Author(s):  
Andrew D. Mumford ◽  
John H. McVey
Keyword(s):  
Tissue Factor ◽  
Coagulation Factor ◽  
Fibrin Clot ◽  
Factor Vii ◽  
Protease Activated Receptors ◽  
Coagulation Factor Vii ◽  
Ischaemia Reperfusion ◽  
Important Mediator ◽  
Low Levels ◽  
Coagulation Pathway

The interaction between cell-surface tissue factor (TF) and the plasma coagulation factor VII (FVII) initiates the coagulation network that leads to the generation of thrombin and the formation of a fibrin clot. Thrombin also activates cellular protease activated receptors (PARs) through which it activates components of the inflammatory pathway. TF is expressed constitutively by cardiomyocytes and evidence from mice transgenic for a human TF mini-gene that express very low levels of human TF suggests that the TF-FVII interaction is critical for haemostasis within the heart. Pathological contact between TF and FVII may occur in the heart during ischaemia-reperfusion (I-R) injury and this may lead to activation of coagulation and thrombin generation. Evidence from animal models now suggests that thrombin is an important mediator of inflammation in I-R injury. The coagulation pathway therefore represents a novel therapeutic target for intervention in the prevention of I-R injury.

A frequent human coagulation Factor VII mutation (A294V, c152) in loop 140s affects the interaction with activators, tissue factor and substrates

2002 ◽  
Vol 363 (2) ◽  
pp. 411-416 ◽  
Author(s):  
Raffaella TOSO ◽  
Mirko PINOTTI ◽  
Katherine A. HIGH ◽  
Eleanor S. POLLAK ◽  
Francesco BERNARDI
Keyword(s):  
Tissue Factor ◽  
Coagulation Factor ◽  
Catalytic Efficiency ◽  
Fibrin Clot ◽  
Enzymic Activity ◽  
Factor Ix ◽  
Site Directed Mutagenesis ◽  
Factor Vii ◽  
Factor X ◽  
Coagulation Factor Vii

Activated Factor VII (FVIIa) is a vitamin-K-dependent serine protease that initiates blood clotting after interacting with its cofactor tissue factor (TF). The complex FVIIa—TF is responsible for the activation of Factor IX (FIX) and Factor X (FX), leading ultimately to the formation of a stable fibrin clot. Activated FX (FXa), a product of FVIIa enzymic activity, is also the most efficient activator of zymogen FVII. Interactions of FVII/FVIIa with its activators, cofactor and substrates have been investigated extensively to define contact regions and residues involved in the formation of the complexes. Site-directed mutagenesis and inhibition assays led to the identification of sites removed from the FVIIa active site that influence binding specificity and affinity of the enzyme. In this study we report the characterization of a frequent naturally occurring human FVII mutant, A294V (residue 152 in the chymotrypsin numbering system), located in loop 140s. This region undergoes major rearrangements after FVII activation and is relevant to the development of substrate specificity. FVII A294V shows delayed activation by FXa as well as reduced activity towards peptidyl and macromolecular substrates without impairing the catalytic efficiency of the triad. Also, the interaction of this FVII variant with TF was altered, suggesting that this residue, and more likely loop 140s, plays a pivotal role not only in the recognition of FX by the FVIIa—TF complex, but also in the interaction of FVII with both its activators and cofactor TF.

scholarly journals Circulating Tissue Factor Procoagulant Activity and Thrombin Generation in Patients with Type 2 Diabetes: Effects of Insulin and Glucose

2007 ◽  
Vol 92 (11) ◽  
pp. 4352-4358 ◽  
Author(s):  
Guenther Boden ◽  
Vijender R. Vaidyula ◽  
Carol Homko ◽  
Peter Cheung ◽  
A. Koneti Rao
Keyword(s):  
Type 2 Diabetes ◽  
Tissue Factor ◽  
Blood Coagulation ◽  
Coagulation Factor ◽  
Procoagulant Activity ◽  
Factor Vii ◽  
Coagulation Factor Vii ◽  
Glucose Levels ◽  
Study Protocols

Abstract Context: Type 2 diabetes mellitus (T2DM) is a hypercoagulable state. Tissue factor (TF) is the principal initiator of blood coagulation. Objective: Our objective was to examine the effects of hyperglycemia and hyperinsulinemia on the TF pathway of blood coagulation in T2DM. Design: Three study protocols were used: 1) acute correction of hyperglycemia (with iv insulin) followed by 24 h of euglycemia, 2) 24 h of selective hyperinsulinemia, and 3) 24 h of combined hyperinsulinemia and hyperglycemia. Setting: The study took place at a clinical research center. Study Participants: Participants included 18 T2DM patients and 22 nondiabetic controls. Results: Basal TF-procoagulant activity (TF-PCA), monocyte TF mRNA, plasma coagulation factor VII (FVIIc), and thrombin-anti-thrombin complexes were higher in T2DM than in nondiabetic controls, indicating a chronic procoagulant state. Acutely normalizing hyperglycemia over 2–4 h resulted in a small (∼7%) but significant decline in TF-PCA with no further decline over 24 h. Raising insulin levels alone raised TF-PCA by 30%, whereas raising insulin and glucose levels together increased TF-PCA (by 80%), thrombin-anti-thrombin complexes, and prothrombin fragment 1.2. Plasma FVIIa and FVIIc declined with increases in TF-PCA. Conclusion: We conclude that the combination of hyperglycemia and hyperinsulinemia, common in poorly controlled patients with T2DM, contributes to a procoagulant state that may predispose these patients to acute cardiovascular events.

scholarly journals A frequent human coagulation Factor VII mutation (A294V, c152) in loop 140s affects the interaction with activators, tissue factor and substrates

2002 ◽  
Vol 363 (2) ◽  
pp. 411 ◽  
Author(s):  
Raffaella TOSO ◽  
Mirko PINOTTI ◽  
Katherine A. HIGH ◽  
Eleanor S. POLLAK ◽  
Francesco BERNARDI
Keyword(s):  
Tissue Factor ◽  
Coagulation Factor ◽  
Factor Vii ◽  
Coagulation Factor Vii ◽  
Human Coagulation Factor Vii

scholarly journals Demonstration of the extrinsic coagulation pathway in teleostei: Identification of zebrafish coagulation factor VII

2001 ◽  
Vol 98 (15) ◽  
pp. 8768-8773 ◽  
Author(s):  
J. Sheehan ◽  
M. Templer ◽  
M. Gregory ◽  
R. Hanumanthaiah ◽  
D. Troyer ◽  
...  
Keyword(s):  
Coagulation Factor ◽  
Factor Vii ◽  
Coagulation Factor Vii ◽  
Coagulation Pathway

Coronary no-reflow is caused by shedding of active tissue factor from dissected atherosclerotic plaque

Blood ◽  
2002 ◽  
Vol 99 (8) ◽  
pp. 2794-2800 ◽  
Author(s):  
Diana Bonderman ◽  
Alexander Teml ◽  
Johannes Jakowitsch ◽  
Christopher Adlbrecht ◽  
Mariann Gyöngyösi ◽  
...  
Keyword(s):  
Tissue Factor ◽  
Atherosclerotic Plaque ◽  
Coronary Vessels ◽  
Coagulation Factor ◽  
Particulate Material ◽  
Factor Vii ◽  
Coagulation Factor Vii ◽  
No Reflow ◽  
Coronary Atherosclerotic Plaque ◽  
Distal Protection

Abstract Defined angiographically, no-reflow (NR) manifests as an acute reduction in coronary flow in the absence of epicardial vessel obstruction. One candidate protein to cause coronary NR is tissue factor (TF), which is abundant in atherosclerotic plaque and a cofactor for activated plasma coagulation factor VII. Scrapings from atherosclerotic carotid arteries contained TF activity (corresponding to 33.03 ± 13.00 pg/cm2 luminal plaque surface). Active TF was sedimented, indicating that TF was associated with membranes. Coronary blood was drawn from 6 patients undergoing coronary interventions with the distal protection device PercuSurge GuardWire (Traatek, Miami, FL). Fine particulate material that was recovered from coronary blood showed TF activity (corresponding to 91.1 ± 62.16 pg/mL authentic TF). To examine the role of TF in acute coronary NR, blood was drawn via a catheter from coronary vessels in 13 patients during NR and after restoration of flow. Mean TF antigen levels were elevated during NR (194.3 ± 142.8 pg/mL) as compared with levels after flow restoration (73.27 ± 31.90 pg/mL; P = .02). To dissect the effects of particulate material and purified TF on flow, selective intracoronary injection of atherosclerotic material or purified relipidated TF was performed in a porcine model. TF induced NR in the model, thus strengthening the concept that TF is causal, not just a bystander to atherosclerotic plaque material. The data suggest that active TF is released from dissected coronary atherosclerotic plaque and is one of the factors causing the NR phenomenon. Thus, blood-borne TF in the coronary circulation is a major determinant of flow.

scholarly journals A candidate activation pathway for coagulation factor VII

2019 ◽  
Vol 476 (19) ◽  
pp. 2909-2926
Author(s):  
Tina M. Misenheimer ◽  
Kraig T. Kumfer ◽  
Barbara E. Bates ◽  
Emily R. Nettesheim ◽  
Bradford S. Schwartz
Keyword(s):  
Tissue Factor ◽  
Blood Coagulation ◽  
Factor Viia ◽  
Coagulation Factor ◽  
Factor Ix ◽  
Factor Vii ◽  
Factor X ◽  
Contact Activation ◽  
Coagulation Factor Vii ◽  
Factor Viiia

Abstract The mechanism of generation of factor VIIa, considered the initiating protease in the tissue factor-initiated extrinsic limb of blood coagulation, is obscure. Decreased levels of plasma VIIa in individuals with congenital factor IX deficiency suggest that generation of VIIa is dependent on an activation product of factor IX. Factor VIIa activates IX to IXa by a two-step removal of the activation peptide with cleavages occurring after R191 and R226. Factor IXaα, however, is IX cleaved only after R226, and not after R191. We tested the hypothesis that IXaα activates VII with mutant IX that could be cleaved only at R226 and thus generate only IXaα upon activation. Factor IXaα demonstrated 1.6% the coagulant activity of IXa in a contact activation-based assay of the intrinsic activation limb and was less efficient than IXa at activating factor X in the presence of factor VIIIa. However, IXaα and IXa had indistinguishable amidolytic activity, and, strikingly, both catalyzed the cleavage required to convert VII to VIIa with indistinguishable kinetic parameters that were augmented by phospholipids, but not by factor VIIIa or tissue factor. We propose that IXa and IXaα participate in a pathway of reciprocal activation of VII and IX that does not require a protein cofactor. Since both VIIa and activated IX are equally plausible as the initiating protease for the extrinsic limb of blood coagulation, it might be appropriate to illustrate this key step of hemostasis as currently being unknown.

Sign in / Sign up

Export Citation Format

Share Document