title: Endotoxaemia-augmented murine venous thrombosis is dependent on TLR-4 and ICAM-1, and potentiated by neutropenia.
abstract: Venous thromboembolism is a major cause of death during and immediately post-sepsis. Venous thrombosis (VT) is mediated by cell adhesion molecules and leukocytes, including neutrophil extracellular traps (NETs). Sepsis, or experimentally, endotoxaemia, shares similar characteristics and is modulated via toll like receptor 4 (TLR4). This study was undertaken to determine if endotoxaemia potentiates early stasis thrombogenesis, and secondarily to determine the role of VT TLR4, ICAM-1 and neutrophils (PMNs). Wild-type (WT), ICAM-1-/-and TLR4-/-mice underwent treatment with saline or LPS (10 mg/kg i. p.) alone, or followed by inferior vena cava (IVC) ligation to generate stasis VT. In vivo microscopy of leukocyte trafficking was performed in non-thrombosed mice, and tissue and plasma were harvested during early VT formation. Pre-thrombosis, circulating ICAM-1 was elevated and increased leukocyte adhesion and rolling occurred on the IVC of LPS-treated mice. Post-thrombosis, endotoxaemic mice formed larger, platelet-poor thrombi. Endotoxaemic TLR4-/-mice did not have an augmented thrombotic response and exhibited significantly decreased circulating ICAM-1 compared to endotoxaemic WT controls. Endotoxaemic ICAM-1-/-mice had significantly smaller thrombi compared to controls. Hypothesising that PMNs localised to the inflamed endothelium were promoting thrombosis, PMN depletion using anti-Ly6G antibody was performed. Paradoxically, VT formed without PMNs was amplified, potentially related to endotoxaemia induced elevation of PAI-1 and circulating FXIII, and decreased uPA. Endotoxaemia enhanced early VT occurs in a TLR-4 and ICAM-1 dependent fashion, and is potentiated by neutropenia. ICAM-1 and/or TLR-4 inhibition may be a unique strategy to prevent sepsis-associated VT.
authors.forename: Andrea T
authors.initials: AT
authors.lastname: Obi
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Andraska
authors.forename: Yogendra
authors.initials: Y
authors.lastname: Kanthi
authors.forename: Chase W
authors.initials: CW
authors.lastname: Kessinger
authors.forename: Megan
authors.initials: M
authors.lastname: Elfline
authors.forename: Cathy
authors.initials: C
authors.lastname: Luke
authors.forename: Teruna J
authors.initials: TJ
authors.lastname: Siahaan
authors.forename: Farouc A
authors.initials: FA
authors.lastname: Jaffer
authors.forename: Thomas W
authors.initials: TW
authors.lastname: Wakefield
authors.affiliation: Peter K. Henke, MD, University of Michigan Health System, 1500 E. Medical Center Drive, Cardiovascular Center - 5463, Ann Arbor, MI 48109-5867, USA, Tel.: +1 734 763 0250, Fax: +1 734 647 9867, E-mail: henke@umich.edu.
authors.forename: Peter K
authors.initials: PK
authors.lastname: Henke
mesh_terms: D000818:Animals; D001777:Blood Coagulation; D001792:Blood Platelets / Q000378:metabolism; D002448:Cell Adhesion; D004195:Disease Models, Animal; D019446:Endotoxemia / Q000097:blood / Q000150:complications*; D005169:Factor VIII / Q000378:metabolism; D005340:Fibrinogen / Q000378:metabolism; D018799:Intercellular Adhesion Molecule-1 / Q000235:genetics / Q000378:metabolism*; D036904:Leukocyte Rolling; D008297:Male; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009503:Neutropenia / Q000097:blood / Q000150:complications*; D009504:Neutrophils / Q000378:metabolism*; D015398:Signal Transduction; D013997:Time Factors; D051197:Toll-Like Receptor 4 / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D020246:Venous Thrombosis / Q000097:blood / Q000209:etiology*
chemical_list: C090509:Icam1 protein, mouse; C493487:Tlr4 protein, mouse; D051197:Toll-Like Receptor 4; D018799:Intercellular Adhesion Molecule-1; D005169:Factor VIII; D005340:Fibrinogen
keywords: ICAM-1; LPS; TLR4; cellular adhesion molecules; sepsis; venous thromboembolism; venous thrombosis