ArticleArteriosclerosis, thrombosis, and vascular biology2018
Elevated Plasma Factor IXa Activity in Premenopausal Women on Hormonal Contraception.
Article in Arteriosclerosis, thrombosis, and vascular biology, 2018. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 5 papers.
What it found
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The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
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Who cites it
5 citing papers in PubMed, 10 citations in OpenAlex.
- The effect of combined oral contraceptives on thrombin generation assessed on ST Genesia- a paired clinical study.Thrombosis journal · 2025Article
- A novel factor IXa-specific enzyme-linked immunosorbent assay detects factor IXa in human plasma.Research and practice in thrombosis and haemostasis · 2024Article
- Recent Insights Into the Regulation of Coagulation and Thrombosis.Arteriosclerosis, thrombosis, and vascular biology · 2020Review
- A candidate activation pathway for coagulation factor VII.The Biochemical journal · 2019Article
- Thrombotic Regulation From the Endothelial Cell Perspectives.Arteriosclerosis, thrombosis, and vascular biology · 2018Review
Corrections and comments
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Authors and funding
5 authors at 2 institutions in 2 countries.
Funding
Abstract
objectiveCombined oral contraceptives induce a reversible hypercoagulable state with an enhanced risk of venous thromboembolism, but the underlying mechanism(s) remain unclear. Subjects on combined oral contraceptives also demonstrate a characteristic resistance to APC (activated protein C) in the thrombin generation assay. Here, we report the potential role of plasma factor IXa (FIXa) as a mechanism for hormone-induced systemic hypercoagulability. APPROACH AND
resultsA novel assay was used to determine FIXa activity in plasma samples from volunteer blood donors. Plasma from 36 premenopausal females on hormonal contraception and 35 not on hormonal contraception, 35 postmenopausal females, and 10 males were analyzed for FIXa activity, total PS (protein S), total tissue factor pathway inhibitor (TFPI), and TFPI-α antigen. Premenopausal females on hormonal contraception demonstrated significantly increased FIXa activity and decreased TFPI-α compared with the other groups. Remarkably, FIXa values were not normally distributed in the hormonal contraception group, but skewed toward the high end. Plasma FIXa activity inversely correlated with both TFPI-α and total PS antigen. Ex vivo determination of TF-dependent FIX activation in FV-deficient plasma demonstrated that inhibitory anti-TFPI antibodies enhanced FIXa generation by 2- to 3-fold, whereas addition of 75 nmol/L PS reduced FIXa generation by ≈2-fold. Further, increasing FIXa concentration enhanced APC resistance during TF-triggered plasma thrombin generation.
conclusionsElevation of plasma FIXa activity in association with reductions in TFPI-α and PS is a potential mechanism for systemic hypercoagulability and resistance to APC in premenopausal females on hormonal contraception.
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Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.