Abstract
Activated thrombin-activatable fibrinolysis inhibitor (TAFIa or CPU) is a carboxypeptidase that is able to attenuate fibrinolysis. Although its role in fibrinolysis and inflammation has been studied extensively in vitro, its levels and subsequent effect in vivo has not been studied to the same extent. Using our recently developed assay that is specific for TAFIa, we were able to quantify its levels in plasma samples obtained from an Escherichia coli (E. coli) challenged baboon sepsis model. TAFIa levels accumulated appeared to be E. coli dose dependent, where the lethal dose of 1010 CFU/kg generated a peak TAFIa level of 24 nM by 2 h, which represents almost 32% of total plasma level of its precursor, thrombin-activatable fibrinolysis inhibitor (TAFI or proCPU). Furthermore, our data suggest that there is continual TAFI activation under lethal level of E. coli as the apparent half-life of TAFIa is increased from 8 min to 2.2 h. Two sublethal doses of 108 and 106 CFU/kg generated peak TAFIa levels of 1.1 and 0.4 nM, respectively, both by 6 h. Taken together, our data show that TAFIa is generated at systemic levels, in a dose-dependent manner, that can substantially affect both fibrinolysis and inflammatory response in the E. coli challenged baboon sepsis model.
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Abbreviations
- IIa:
-
Thrombin
- IIa–TM:
-
Thrombin/thrombomodulin complex
- TAFI(a):
-
Thrombin-activatable fibrinolysis inhibitor (activated)
- Pg:
-
Plasminogen
- FN′:
-
Plasmin-modified fibrin
- t-PA:
-
Tissue-type plasminogen activator
- APC/PCI:
-
Activated protein C-protein C inhibitor complex
- E. coli :
-
Escherichia coli
- SLEC:
-
Sublethal E. coli
- LDEC:
-
Lethal E. coli
- HBS:
-
0.02 M HEPES, 0.15 M NaCl, pH 7.4
- 5IAF-Pg:
-
Recombinant Pg with a single mutation of the active site serine to a cysteine (S741C) labelled with 5-iodoacetamidofluorescein (5IAF)
- QSY-FDPs:
-
QSY9 C5 maleimide-labelled fibrin degradation products
- TDP:
-
TAFI-deficient plasma
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Acknowledgments
This work was supported by the Heart and Stroke Foundation of Ontario (T5575) and the National Institutes of Health (P01 HL2046703) (to MEN), the Canadian Institutes of Health Research Fellowship (to PYK), and the Queen’s University Graduate Fellowship (to PYGK).
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Kim, P.Y., Kim, P.Y.G., Taylor, F.B. et al. Thrombin-activatable fibrinolysis inhibitor is activated in vivo in a baboon model of Escherichia coli induced sepsis. J Thromb Thrombolysis 33, 412–415 (2012). https://doi.org/10.1007/s11239-011-0676-4
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DOI: https://doi.org/10.1007/s11239-011-0676-4