Inserm, Institut national de la santé et de la recherche médicale
Faculté de pharmacie, Aix Marseille Université

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Monocyte IL-10 produced in response to lipopolysaccharide modulates thrombin generation by inhibiting tissue factor expression and release of active tissue factor-bound microparticles

Poitevin S., Cochery-Nouvellon E., Dupont A., Nguyen P. 2007, 97/4 (Apr). Thrombosis and Haemostasis. Pages : 598-607. Impact factor : 3.501


Lipopolysaccharide (LPS)-stimulated monocytes are known to have a procoagulant effect.This property is currently explained by the fact that monocytes, in response to LPS, can express tissue factor (TF) and undergo a process of membrane microvesiculation. Interleukin-10 (IL-10) has been shown to downregulate TF expression and inhibit procoagulant activity (PCA). In order to further characterize the inhibitory effect of IL-10 on LPS-induced PCA, we used the integrated system of analysis of kinetics of thrombin generation in normal plasma (thrombinography). For this, we developed an original method of elutriation allowing to obtain a highly purified monocyte preparation, under endotoxin-free conditions. Thrombin generation was measured using a highly sensitive and specific fluorogenic method which we adapted to inhibit the contact factor pathway.

Results show that recombinant human IL-10 decreased the kinetics of thrombin generation in a dose-dependent manner. Furthermore, the inhibition of endogenous IL-10 released by monocytes in response to LPS is associated with an increase in the kinetics of thrombin generation.We demonstrated that this effect was a consequence of the up-regulation of TF expression and TF-bound microparticle release. In conclusion, we report that IL-10 can regulate thrombin generation in conditions close to physiology as allowed by thrombinography,and that endogenous IL-10 regulates TF expression and release of active TF-bound microparticles by a negative feed back loop through IL-10 receptor α.