The fibrinolytic cascade functions to remove blood clots through the enzyme plasmin, which is generated as needed in a controlled fashion by a complex series of reactions. The proposed work is designed to provide a fuller, more quantitative understanding of the properties of the cascade and how its activity is regulated. The project is intimately related to the mission of the NIH because it is directed at obtaining a better understanding of the mechanisms which, when improperly regulated, underlie a good deal of the morbidity and mortality that afflict western society and manifest as heart attacks, stokes and other thrombotic pathologies.
SPECIFIC AIMS :
The specific aims of the project are:(1) To determine the dynamics of the interactions between fibrin, tPA and plasminogen .involved in plasminogen activation;(2) To investigate the enzymology of key reactions in the fibrinolytic cascade including: a) the fibrin dependent conversion of glu plasminogen to lys plasminogen by plasmin with and without TAFIa, b) the down regulation by fibrin of the inhibition of one and two chain tPA by PAI-1 with and without TAFIa, c) the activation of lys plasminogen by tPA on plasmin modified fibrin with and without TAFIa, and d) the plasmin catalyzed digestion of fibrin;(3) To determine the effects of TAFIa on components and reactions of the coagulation cascade;(4) To determine the effect of chronic TAFI activation on clot lysis;(5) To investigate the inhibition of fibrinolysis by platelets and study fibrinolysis in whole blood;(6) To determine the time courses and extents of TAFI activation in normal and factor VIII deficient whole blood and plasmas;and (7) To continue the development of the Lys Speed computer model of the fibrinolytic cascade. RESEARCH DESIGN AND METHODS:
The first aim will be accomplished by measuring the dynamics of the interactions by which the tPA-fibrin-plasminogen complex is assembled;the second will be accomplished by standard measurements of steady-state kinetics;the third, in collaboration with Dr. Mann, by exposing the clotting factors to TAFIa and assessing functional consequences;the forth by chronically generating TAFIa and monitoring clot lysis; the fifth, in collaboration with Drs. Tracy and Samis, by measuring lysis in the presence of platelets, whole blood, and other blood cells;the sixth, in collaboration with Dr. Brummel-Ziedins by measuring TAFIa activation and clot lysis in normal and factor VIIl-deficient whole blood or plasma;and the seventh by refining and validating the computer model of the fibrinolytic cascade.

Public Health Relevance

The relevance of this work to public health is that it will lead to a better understanding of the means by which blood clots are removed and therefore to a better understanding of pathologies associated with improperly balanced fibrin deposition and removal such as venous thrombosis, pulmonary embolism, heart attack and stroke. In so doing, this work may contribute to better means to diagnose, treat and prevent these maladies.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Program Projects (P01)
Project #
5P01HL046703-20
Application #
8309797
Study Section
Heart, Lung, and Blood Initial Review Group (HLBP)
Project Start
Project End
2013-07-31
Budget Start
2011-08-01
Budget End
2013-07-31
Support Year
20
Fiscal Year
2011
Total Cost
$189,985
Indirect Cost
Name
University of Vermont & St Agric College
Department
Type
DUNS #
066811191
City
Burlington
State
VT
Country
United States
Zip Code
05405
Kusak, Piotr; Czarnecka, Danuta; Gissel, Matthew et al. (2016) Activated factor IX, factor XI and tissue factor identify patients with permanent atrial fibrillation treated with warfarin who are at risk of ischemic stroke. Arch Med Sci 12:1000-1007
Bouchard, Beth A; Chapin, John; Brummel-Ziedins, Kathleen E et al. (2015) Platelets and platelet-derived factor Va confer hemostatic competence in complete factor V deficiency. Blood 125:3647-50
Bouchard, Beth A; Gissel, Matthew T; Whelihan, Matthew F et al. (2014) Platelets do not express the oxidized or reduced forms of tissue factor. Biochim Biophys Acta 1840:1188-93
de Haan, Hugoline G; Bezemer, Irene D; Vossen, Carla Y et al. (2014) Genetic variants in Cell Adhesion Molecule 1 (CADM1): a validation study of a novel endothelial cell venous thrombosis risk factor. Thromb Res 134:1186-92
Undas, A; Brummel-Ziedins, K E; Mann, K G (2014) Anticoagulant effects of statins and their clinical implications. Thromb Haemost 111:392-400
Whelihan, Matthew F; Kiankhooy, Armin; Brummel-Ziedins, Kathleen E (2014) Thrombin generation and fibrin clot formation under hypothermic conditions: an in vitro evaluation of tissue factor initiated whole blood coagulation. J Crit Care 29:24-30
Brummel-Ziedins, Kathleen E; Everse, Stephen J; Mann, Kenneth G et al. (2014) Modeling thrombin generation: plasma composition based approach. J Thromb Thrombolysis 37:32-44
Krudysz-Amblo, Jolanta; Jennings 2nd, Mark E; Knight, Tyler et al. (2013) Disulfide reduction abolishes tissue factor cofactor function. Biochim Biophys Acta 1830:3489-96
Ayombil, F; Abdalla, S; Tracy, P B et al. (2013) Proteolysis of plasma-derived factor V following its endocytosis by megakaryocytes forms the platelet-derived factor V/Va pool. J Thromb Haemost 11:1532-9
Baker, Jason V; Brummel-Ziedins, Kathleen; Neuhaus, Jacqueline et al. (2013) HIV replication alters the composition of extrinsic pathway coagulation factors and increases thrombin generation. J Am Heart Assoc 2:e000264

Showing the most recent 10 out of 247 publications