title: Microparticles in vascular disorders: how tissue factor-exposing vesicles contribute to pathology and physiology.
abstract: Coagulation is initiated by tissue factor (TF). Coagulant TF is constitutively expressed by extravascular cells, but there is increasing evidence that TF can also be present within the blood, in particular during pathological conditions. Such TF is exposed on circulating cell-derived vesicles, and its presence has been associated with development of disseminated intravascular coagulation and venous thrombosis. For example, the presence of TF-exposing vesicles in the blood of cancer patients may be associated with their high risk of developing venous thromboembolism. Remarkably, high levels of coagulant TF-exposing vesicles are present in other body fluids such as saliva and urine of healthy persons, suggesting that these vesicles play a physiological role. We postulate that the presence of TF-exposing vesicles in body fluids as saliva and urine provides an additional source of coagulant TF that promotes coagulation, thereby reducing blood loss and contributing to host defence by reducing the risk of microorganisms entering the "milieu intérieur".
authors.affiliation: Department of Vascular Medicine of the Academic Medical Centre of the University of Amsterdam, Amsterdam, The Netherlands.
authors.forename: Ankie
authors.initials: A
authors.lastname: Kleinjan
authors.forename: Anita N
authors.initials: AN
authors.lastname: Böing
authors.forename: Auguste
authors.initials: A
authors.lastname: Sturk
authors.forename: Rienk
authors.initials: R
authors.lastname: Nieuwland
mesh_terms: D001777:Blood Coagulation; D055252:Cell-Derived Microparticles / Q000378:metabolism* / Q000473:pathology; D006801:Humans; D009369:Neoplasms / Q000097:blood / Q000150:complications; D012307:Risk Factors; D012463:Saliva / Q000378:metabolism; D013925:Thromboplastin / Q000378:metabolism*; D014556:Urine / Q000737:chemistry; D054556:Venous Thromboembolism / Q000097:blood* / Q000209:etiology / Q000473:pathology / Q000503:physiopathology
chemical_list: D013925:Thromboplastin