Abstract Number: PB0266
Meeting: ISTH 2020 Congress
Background: Corn Trypsin Inhibitor (CTI) is a known inhibitor of coagulation factor (F) XIIa. It is used – for example – to limit contact activation (CA) in thrombin generation tests when analyzing the tissue factor pathway. There is some discussion if CTI could inhibit FXIa and the thrombin feedback loop at particular concentrations.
Aims: With the rising interest in CA assays, one has to question the need for CTI to limit CA due to blood sample processing. We aimed to investigate the role of CTI in FXIa-Antithrombin (AT) complex ELISA in different conditions to optimize the preanalytical phase of CA assays.
Methods: We performed an in-house ELISA using anti-FXI and biotinylated anti-AT goat antibodies to analyze normal human plasma. Samples with or without CTI (50 µg mL-1) were activated in centrifuged glass tubes (N=10) or by adding different concentrations of commercially available synthetic phospholipids and silica (SynthASil) in recalcified citrated plasma (N=5). Blood sampling conditions were identical with attention for undesired CA; e.g. no extra tubing, regular needles, and immediate processing. The difference in absorbances was statistically analyzed at a 0.05 significance level using Wilcoxon Signed Ranks test as the sample size is currently still small and normal distribution could not be assumed.
Results: If one compares samples activated in centrifuged glass tubes with or without CTI, there is no significant difference in FXIa-AT complex formation (P-value 0.721). The presence of CTI in citrated plasma, activated with SynthASil and calcium chloride seems to have no significant impact on FXIa-AT complex formation compared to solely citrated sample collection (P-value 0.225).
Conclusions: These preliminary results suggest that with careful sample collection, the role for CTI in FXIa-AT complex ELISA is rather small. CTI, therefore, could potentially be omitted in favor of simplified sample collections within clinical trials, for example.
To cite this abstract in AMA style:Engelen MM, Vandenbriele C, Verhamme P, Vanassche T. Corn Trypsin Inhibitor in the Preanalytical Phase of Contact Activation Assays [abstract]. Res Pract Thromb Haemost. 2020; 4 (Suppl 1). https://abstracts.isth.org/abstract/corn-trypsin-inhibitor-in-the-preanalytical-phase-of-contact-activation-assays/. Accessed May 6, 2021.
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