Tags

Type your tag names separated by a space and hit enter

Inhibitory effects of LDL-associated tissue factor pathway inhibitor.
Thromb Res 2014; 134(1):132-7TR

Abstract

INTRODUCTION

Tissue factor pathway inhibitor (TFPI) is present in plasma as full-length free TFPI (TFPIα) and as C-terminally degraded forms mainly associated with low-density lipoprotein particles (LDL-TFPI). Addition of TFPIα to plasma induces a prolongation of the clotting time when tested in a diluted prothrombin time (dPT) assay, whereas no prolongation is observed with LDL-TFPI or truncated recombinant TFPI (TFPI 1-161). The aim was to further characterize kinetic properties of purified LDL-TFPI in thrombin generation and chromogenic activity assays.

MATERIALS AND METHODS

LDL-TFPI was purified from human plasma by sequential flotation ultracentrifugation. Thrombin generation was measured in human plasma or in FVIII-immunodepleted plasma using either 1 pM tissue factor and 4 μM phospholipids or 0.5 nM factor Xa (FXa) and 4 μM phospholipids, respectively.

RESULTS

TFPIα prolonged the lag-phase and decreased the thrombin peak in tissue factor-induced thrombin generation, whereas LDL-TFPI exclusively decreased the peak height of thrombin without effecting the lag phase. Steady-state and transient kinetics showed that LDL-TFPI was a more potent inhibitor of FXa than TFPIα and TFPI 1-161, indicating that FXa inhibition was not rate determining for the lag phase, whereas it appeared to affect thrombin generation during the propagation phase. This was supported by FXa-induced thrombin generation showing that LDL-TFPI, compared with TFPIα, more actively decreased the peak height.

CONCLUSIONS

Our results suggest that LDL-TFPI affects thrombin generation during the propagation phase, and is kinetically different from TFPI 1-161. It may therefore play a more prominent physiological role in vivo than hereto anticipated from dPT measurements.

Authors+Show Affiliations

Haemophilia, in vitro Biology, Biopharmaceutical Research Unit, Novo Nordisk A/S, Måløv, Denmark.Haemophilia, in vitro Biology, Biopharmaceutical Research Unit, Novo Nordisk A/S, Måløv, Denmark.Haemophilia, in vitro Biology, Biopharmaceutical Research Unit, Novo Nordisk A/S, Måløv, Denmark. Electronic address: lcp@novonordisk.com.

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

24787991

Citation

Augustsson, Cecilia, et al. "Inhibitory Effects of LDL-associated Tissue Factor Pathway Inhibitor." Thrombosis Research, vol. 134, no. 1, 2014, pp. 132-7.
Augustsson C, Hilden I, Petersen LC. Inhibitory effects of LDL-associated tissue factor pathway inhibitor. Thromb Res. 2014;134(1):132-7.
Augustsson, C., Hilden, I., & Petersen, L. C. (2014). Inhibitory effects of LDL-associated tissue factor pathway inhibitor. Thrombosis Research, 134(1), pp. 132-7. doi:10.1016/j.thromres.2014.03.043.
Augustsson C, Hilden I, Petersen LC. Inhibitory Effects of LDL-associated Tissue Factor Pathway Inhibitor. Thromb Res. 2014;134(1):132-7. PubMed PMID: 24787991.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Inhibitory effects of LDL-associated tissue factor pathway inhibitor. AU - Augustsson,Cecilia, AU - Hilden,Ida, AU - Petersen,Lars C, Y1 - 2014/04/01/ PY - 2014/02/04/received PY - 2014/03/13/revised PY - 2014/03/26/accepted PY - 2014/5/3/entrez PY - 2014/5/3/pubmed PY - 2015/4/17/medline KW - Anticoagulant KW - Haemostasis KW - lipoprotein KW - tissue factor SP - 132 EP - 7 JF - Thrombosis research JO - Thromb. Res. VL - 134 IS - 1 N2 - INTRODUCTION: Tissue factor pathway inhibitor (TFPI) is present in plasma as full-length free TFPI (TFPIα) and as C-terminally degraded forms mainly associated with low-density lipoprotein particles (LDL-TFPI). Addition of TFPIα to plasma induces a prolongation of the clotting time when tested in a diluted prothrombin time (dPT) assay, whereas no prolongation is observed with LDL-TFPI or truncated recombinant TFPI (TFPI 1-161). The aim was to further characterize kinetic properties of purified LDL-TFPI in thrombin generation and chromogenic activity assays. MATERIALS AND METHODS: LDL-TFPI was purified from human plasma by sequential flotation ultracentrifugation. Thrombin generation was measured in human plasma or in FVIII-immunodepleted plasma using either 1 pM tissue factor and 4 μM phospholipids or 0.5 nM factor Xa (FXa) and 4 μM phospholipids, respectively. RESULTS: TFPIα prolonged the lag-phase and decreased the thrombin peak in tissue factor-induced thrombin generation, whereas LDL-TFPI exclusively decreased the peak height of thrombin without effecting the lag phase. Steady-state and transient kinetics showed that LDL-TFPI was a more potent inhibitor of FXa than TFPIα and TFPI 1-161, indicating that FXa inhibition was not rate determining for the lag phase, whereas it appeared to affect thrombin generation during the propagation phase. This was supported by FXa-induced thrombin generation showing that LDL-TFPI, compared with TFPIα, more actively decreased the peak height. CONCLUSIONS: Our results suggest that LDL-TFPI affects thrombin generation during the propagation phase, and is kinetically different from TFPI 1-161. It may therefore play a more prominent physiological role in vivo than hereto anticipated from dPT measurements. SN - 1879-2472 UR - https://www.unboundmedicine.com/medline/citation/24787991/Inhibitory_effects_of_LDL_associated_tissue_factor_pathway_inhibitor_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0049-3848(14)00173-X DB - PRIME DP - Unbound Medicine ER -