title: Antithrombotic activity of TNF-alpha.
abstract: Basic and clinical observations suggest that thrombosis and inflammation are closely related. Here we addressed the role played by TNF-alpha in thrombus formation and growth in an in vivo mouse model. Using intravital microscopy, we show that systemic administration of TNF-alpha at doses found in sepsis transiently inhibits thrombus formation and delays arterial occlusion upon vascular injury. These results were reflected in a prolonged bleeding time. Platelets isolated from the TNF-alpha-treated mice showed a marked decrease in fibrinogen binding and P-selectin expression as well as reduced platelet aggregation in response to various agonists. In contrast, in vitro treatment of platelets with TNF-alpha did not affect their function. TNF receptor 1- and 2-deficient mice exhibited normal thrombogenesis in the presence of TNF-alpha. Additionally, the inhibitory effect of TNF-alpha was lost either after treatment with NG-monomethyl-l-arginine, an inhibitor of NO production, or in mice deficient for iNOS. These results indicate that under inflammatory conditions, when leukocytes need free passage to transmigrate into tissues, TNF-alpha decreases platelet activation and inhibits thrombi formation. This effect is not exerted directly on platelets but mediated through the rapid generation of NO in the vessel wall.
authors: The CBR Institute for Biomedical Research Inc, Boston, Massachusetts 02115, USA.
authors: Beatrice
authors: B
authors: Cambien
authors: Wolfgang
authors: W
authors: Bergmeier
authors: Simin
authors: S
authors: Saffaripour
authors: Heather A
authors: HA
authors: Mitchell
authors: Denisa D
authors: DD
authors: Wagner
mesh_terms: D000818:Animals; D001158:Arteries / Q000033:anatomy & histology / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D001777:Blood Coagulation / Q000502:physiology; D001792:Blood Platelets / Q000378:metabolism; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005343:Fibrinolytic Agents / Q000378:metabolism / Q000494:pharmacology / Q000627:therapeutic use*; D006439:Hemodynamics / Q000502:physiology; D006801:Humans; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008853:Microscopy / Q000379:methods; D019001:Nitric Oxide Synthase / Q000235:genetics / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II; D019007:P-Selectin / Q000235:genetics / Q000378:metabolism; D018124:Receptors, Tumor Necrosis Factor / Q000235:genetics / Q000378:metabolism; D013927:Thrombosis / Q000097:blood / Q000188:drug therapy* / Q000378:metabolism; D013997:Time Factors; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism / Q000494:pharmacology / Q000627:therapeutic use*; D019323:omega-N-Methylarginine / Q000494:pharmacology
chemical_list: D004791:Enzyme Inhibitors; D005343:Fibrinolytic Agents; D019007:P-Selectin; D018124:Receptors, Tumor Necrosis Factor; D014409:Tumor Necrosis Factor-alpha; D019323:omega-N-Methylarginine; C496319:NOS2 protein, human; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; C496317:Nos2 protein, mouse