BACKGROUND: We systematically analyzed the synergistic effect of: (i) cytokine-mediated inflammatory activation of endothelial cells (ECs) with and (ii) shear-mediated platelet activation (SMPA) as a potential contributory mechanism to intraventricular thrombus formation in the setting of left ventricular assist device (LVAD) support. METHODS: Intact and shear-activated human platelets were exposed to non-activated and cytokine-activated ECs. To modulate the level of LVAD-related shear activation, platelets were exposed to shear stress patterns of varying magnitude (30, 50, and 70 dynes/cm2, 10 minutes) via a hemodynamic shearing device. ECs were activated via exposure to inflammatory tumor necrosis factor-α (TNF-α 10 and 100 ng/ml, 24 hours), consistent with inflammatory activation recorded in patients on LVAD circulatory support. RESULTS: Adhesivity of shear-activated platelets to ECs was significantly higher than that of intact/unactivated platelets, regardless of the initial activation level (70 dynes/cm2 shear-activated platelets vs intact platelets: +80%, p < 0.001). Importantly, inflammatory activation of ECs amplified platelet prothrombinase activity progressively with increasing shear stress magnitude and TNF-α concentration: thrombin generation of 70 dynes/cm2 shear-activated platelets was 2.6-fold higher after exposure and adhesion to 100 ng/ml TNF-α‒activated ECs (p < 0.0001). CONCLUSIONS: We demonstrated synergistic effect of SMPA and cytokine-mediated EC inflammatory activation to enhance EC‒platelet adhesion and platelet prothrombotic function. These mechanisms may contribute to intraventricular thrombosis in the setting of mechanical circulatory support.

Prothrombotic activity of cytokine-activated endothelial cells and shear-activated platelets in the setting of ventricular assist device support

Bono N.;Fiore G. B.;PAPPALARDO, FABIO;Candiani G.;Redaelli A.;
2019

Abstract

BACKGROUND: We systematically analyzed the synergistic effect of: (i) cytokine-mediated inflammatory activation of endothelial cells (ECs) with and (ii) shear-mediated platelet activation (SMPA) as a potential contributory mechanism to intraventricular thrombus formation in the setting of left ventricular assist device (LVAD) support. METHODS: Intact and shear-activated human platelets were exposed to non-activated and cytokine-activated ECs. To modulate the level of LVAD-related shear activation, platelets were exposed to shear stress patterns of varying magnitude (30, 50, and 70 dynes/cm2, 10 minutes) via a hemodynamic shearing device. ECs were activated via exposure to inflammatory tumor necrosis factor-α (TNF-α 10 and 100 ng/ml, 24 hours), consistent with inflammatory activation recorded in patients on LVAD circulatory support. RESULTS: Adhesivity of shear-activated platelets to ECs was significantly higher than that of intact/unactivated platelets, regardless of the initial activation level (70 dynes/cm2 shear-activated platelets vs intact platelets: +80%, p < 0.001). Importantly, inflammatory activation of ECs amplified platelet prothrombinase activity progressively with increasing shear stress magnitude and TNF-α concentration: thrombin generation of 70 dynes/cm2 shear-activated platelets was 2.6-fold higher after exposure and adhesion to 100 ng/ml TNF-α‒activated ECs (p < 0.0001). CONCLUSIONS: We demonstrated synergistic effect of SMPA and cytokine-mediated EC inflammatory activation to enhance EC‒platelet adhesion and platelet prothrombotic function. These mechanisms may contribute to intraventricular thrombosis in the setting of mechanical circulatory support.
Endothelial cells; inflammation; platelets; shear stress; thrombosis; ventricular assist device
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11311/1097788
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