Background: All major reactions of the coagulation cascade are membrane-dependent. There are different sources of negatively charged membranes such as activated platelets, fibroblasts, smooth muscle cells, endothelial cells and their microparticles. Was shown that RBC also can effect plasma coagulation by different ways but it’s not considered which way is more important.

Aims: In this work was investigated the ability of RBCs to support generation of fXa by the intrinsic fX-activating complex and to bind the components of this complex.

Methods: RBCs were isolated from whole blood by washing. Written informed consent was given by all participants, and the study was approved by the institutional ethical committee. Flow cytometry were used to investigate interaction of FITC-labeled factors with the membranes of RBCs. The quantity of generated FXa was determined by chromogenic assay with specific substrate S-2765. For flow cytometry and chromogenic assay were used native RBCs and RBCs after osmotic shock.

Results: FX activation via instrinct tenase was studied in presence of either RBCs, or platelets. In both cases, the rate of the reaction was proportional to the concentration of added cells. The effect of RBCs in concentration 2×106 1/ul near 40% of normal haematocrite was similar to physiological concentration of activated platelets. Was shown PS-positive RBCs predominantly interacted with coagulation factors and increasing activation fX via intrinsic tenase.

Conclusions: We have shown that reaction of activation fX via intrinsic tenase is efficiently accelerated by RBCs.
This study was supported by the Russian Foundation for Basic Research grant 19-04-00615.

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ISTH Congress Abstracts - https://abstracts.isth.org/abstract/red-blood-cells-support-factor-x-activation-via-intrinsic-tenase/