Alan E. Mast

Brian C. Cooley

Catherine E. Bonesho

Cooley BC

Drake TA

Huang ZF

Josephine P. Ferrel

Novotny WF

Rauch U

Susan A. Maroney


            Objective—
            Tissue factor (TF)–factor VIIa initiates blood coagulation and is found on microparticles that accumulate within intravascular thrombi. Tissue factor pathway inhibitor (TFPI), a factor Xa (fXa)–dependent inhibitor of TF–factor VIIa, is produced by megakaryocytes and is present in platelets. We sought to determine the role of platelet TFPI in regulation of thrombus growth.
          
          
            Methods and Results—
            
              Western blot analyses demonstrated that murine platelets produce TFPIα, the most evolutionarily conserved alternatively spliced isoform of TFPI. A mouse model of hematopoietic cell TFPI deficiency was developed by transplanting irradiated TFPI
              +/−
              mice with TFPI
              −/−
              fetal liver cells. Platelets from transplanted mice totally lack TFPI inhibitory activity. An electrolytic vascular injury model was used to assess thrombus growth in the femoral vein and carotid artery. Mice lacking hematopoietic TFPI developed larger femoral vein and carotid artery thrombi than TFPI
              +/−
              mice transplanted with TFPI
              +/+
              hematopoietic cells, as evidenced by increased platelet accumulation.
            
          
          
            Conclusion—
            Hematopoietic TFPI limits thrombus growth following vascular injury. Because platelets are the primary hematopoietic cell accumulating within a growing thrombus, these findings suggest that TFPI present within platelets functions to limit intravascular thrombus growth, likely through inhibition of the procoagulant activity of blood borne TF.
          </jats:sec

Crossref

Arteriosclerosis Thrombosis and Vascular Biology

Murine Hematopoietic Cell Tissue Factor Pathway Inhibitor Limits Thrombus Growth

Murine Hematopoietic Cell Tissue Factor Pathway Inhibitor Limits Thrombus Growth

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