Circulating tissue factor, tissue factor pathway inhibitor and D-dimer in umbilical cord blood of normal term neonates and adult plasma

SummaryTissue factor pathway inhibitor (TFPI) inhibits tissue factor, a potent coagulation initiator. Limited evidence suggests that low TFPI levels are associated with increased risk of venous thromboembolism (VTE). We measured total TFPI in a nested case-control study in the Longitudinal Investigation of Thromboembolism Etiology. Control subjects were frequency matched 2:1 to cases on age, sex, race, and cohort. Odds ratios (ORs) for VTE by TFPI levels were computed using logistic regression models adjusting for age, race, sex, coagulation factors (factors VII, VIII, IX, XI, D-dimer), and body mass index (BMI). To evaluate for greater than additive interactions, we calculated the percent relative excess risk due to interaction between TFPI and other VTE risk factors. A total of 534 cases of VTE occurred and matched to 1,091 controls. Mean baseline TFPI in ng/ml (standard deviation) in those who developed VTE and controls was 36.4 (12.8) and 35.0 (11.1), respectively. Higher TFPI was associated with male sex, age, BMI, factors VII, VIII, IX, XI, and D-dimer. TFPI level did not differ by ethnicity, factor V Leiden, or pro-thrombin G20210A. Compared with those in the upper 95%, the bottom 5% of TFPI had an age-, sex-, race-, and study-adjusted OR (95% CI) of 1.35 (0.86, 2.12) for VTE. Adjusting for factors VII, VIII, IX, and XI the OR was 1.93 (1.05, 3.53). Further addition of D-dimer and BMI to this model decreased the OR to 1.70 (0.98, 2.93). Low TFPI did not demonstrate greater than additive interaction with other VTE risk factors.

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The anticoagulant action of recombinant human activated protein C (rhAPC, Drotrecogin α activated): comparison between cord and adult plasma

Thrombosis and Haemostasis ◽

10.1160/th03-12-0739 ◽

2004 ◽

Vol 91 (05) ◽

pp. 912-918 ◽

Cited By ~ 10

Author(s):

Siegfried Gallistl ◽

Martin Koestenberger ◽

Katrin Baier ◽

Peter Fritsch ◽

Joachim Greilberger ◽

...

Keyword(s):

Tissue Factor ◽

Protein C ◽

Tissue Factor Pathway Inhibitor ◽

Activated Protein C ◽

Clotting Time ◽

Promising Candidate ◽

Anticoagulant Action ◽

Adult Plasma ◽

Tissue Factor Pathway

SummaryThe present study was performed to compare the anticoagulant efficiency of recombinant human activated protein C (rhAPC) in cord with that in adult plasma. RhAPC is a promising candidate to improve the outcome of severe sepsis. However, different anticoagulant efficiency of rhAPC in cord compared with adult plasma has to be expected due to physiological low plasma levels of tissue factor pathway inhibitor (TFPI) and antithrombin (AT) present in neonates, two inhibitors known to markedly influence the anticoagulant action of APC. Clot formation was induced in our experiments by addition of high (30 µM) or low (20 pM) amounts of lipidated tissue factor (TF). High amounts of TF are conventionally applied in standard clotting assays, whereas plasma activation with low amounts of TF probably better matches the conditions in vivo. We demonstrate that under low coagulant challenge increasing amounts of rhAPC (0.1 – 0.5 µg/ml final plasma concentration) dose-dependently prolonged clotting time and suppressed thrombin potential and prothrombin fragment 1 + 2 generation in both cord and adult plasma. The same was true for experiments performed under high coagulant challenge when 4 – 16 µg/ml of rhAPC were added. Whereby, cord plasma was significantly more susceptible to addition of rhAPC in the presence of high amounts of TF and adult plasma was significantly more susceptible to addition of rhAPC in the presence of low amounts of TF. We demonstrate that increased anticoagulant efficiency of rhAPC in adult plasma under low coagulant challenge is attributable to the physiological high levels of TFPI and AT present in adults.

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