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Antithrombotic activity of TNF-alpha
Beatrice Cambien1, Wolfgang Bergmeier, Simin Saffaripour
1The CBR Institute for Biomedical Research Inc, Boston, Massachusetts 02115, USA.
The Journal of Clinical Investigation
|November 18, 2003
Summary
Tumor necrosis factor-alpha (TNF-alpha) transiently inhibits thrombus formation and arterial occlusion during inflammation. This effect, mediated by nitric oxide (NO), reduces platelet activation and aggregation, crucial for leukocyte transmigration.
Area of Science:
- Immunology
- Hematology
- Vascular Biology
Background:
- Thrombosis and inflammation are closely interconnected.
- Tumor necrosis factor-alpha (TNF-alpha) is a key inflammatory cytokine.
- The precise role of TNF-alpha in thrombus formation requires further elucidation.
Purpose of the Study:
- To investigate the role of TNF-alpha in thrombus formation and growth in vivo.
- To understand the mechanisms underlying TNF-alpha's effect on platelet function and thrombosis.
Main Methods:
- Intravital microscopy in a mouse model to observe thrombus formation.
- Assessment of platelet function (fibrinogen binding, P-selectin expression, aggregation).
- Utilized TNF receptor-deficient mice and nitric oxide synthase inhibitors.
Main Results:
- Systemic TNF-alpha administration inhibited thrombus formation and delayed arterial occlusion.
- Platelets from TNF-alpha-treated mice showed reduced activation and aggregation.
- The inhibitory effect was dependent on nitric oxide (NO) generation via inducible nitric oxide synthase (iNOS), not direct platelet action.
Conclusions:
- TNF-alpha inhibits thrombus formation and platelet activation under inflammatory conditions.
- This effect is mediated indirectly through NO production in the vessel wall.
- This mechanism facilitates leukocyte transmigration during inflammation.