Interleukin 1 induces endothelial cell procoagulant while suppressing cell-surface anticoagulant activity

Area of Science:

• Biomedical Science
• Vascular Biology
• Inflammation Research

Background:

• Endothelial cells play a dual role in hemostasis, balancing anticoagulant and procoagulant activities.
• Quiescent endothelium favors anticoagulation, while activated endothelium can promote coagulation.

Purpose of the Study:

• To investigate the effect of interleukin 1 (IL-1) on the procoagulant and anticoagulant properties of rabbit aortic endothelium.
• To determine if IL-1 can induce a prethrombotic state on the endothelial surface.

Main Methods:

• Intravenous infusion of purified recombinant interleukin 1 into rabbits.
• Study of native aortic endothelium coagulant properties post-infusion.
• Measurement of tissue factor activity and protein C pathway function.
• Scanning electron microscopy of major arteries.

Main Results:

• IL-1 infusion dose- and time-dependently increased tissue factor activity by over 10-fold within 3-5 hours.
• Endothelial protein C activation decreased by 72%, and activated protein C-protein S complex assembly reduced by over 90%.
• Scanning electron microscopy revealed fibrin strands on the endothelial surface, particularly at bifurcations.

Conclusions:

• Interleukin 1 significantly shifts the endothelial balance towards a procoagulant state, favoring clot formation.
• Perturbed endothelium induced by IL-1 serves as a model for the early stages of thrombosis.
• This study highlights the role of inflammatory mediators in initiating thrombotic events.