title: Clinical relevance of hypercoagulability and possible hypofibrinolysis associated with estrone and estriol.
abstract: Estrone (E1) and Estriol (E3) are endogenous female hormones, present in increased concentrations during female specific physiological processes (menopause and pregnancy respectively) that are associated with increased venous thrombotic risk. These hormones are also used as hormone therapies that are also associated with increased thromboembolism risk. Viscoelastic analysis revealed no significant difference to clot formation after hormone addition, however morphological analysis showed that the addition of both E1and E3result in fibrin clots composed of thinner fibrin fibers arranged in dense matted networks. These changes to the fibrin network ultrastructure are indicative of a prothrombotic state but may also indicate hypofibrinolysis. We therefore conclude that the increased risk of venous thrombosis during pregnancy and menopause may originate from a combination of hypercoagulation and a possible hypofibrinolytic mechanism of these hormones. Therefore females with a hypercoagulable tendency that fall pregnant or enter menopause need to be monitored to prevent venous thrombotic events. The decision to use hormone therapies during and after menopause should not be taken lightly and the risk-reward scale should be closely examined to ensure it does not tip towards thrombosis and subsequent thrombotic events that ultimately could have been prevented.
authors.affiliation: Department of Physiology, School of Medicine, Faculty of Health Sciences, University of Pretoria, South Africa.
authors.forename: Albe C
authors.identifier: http://orcid.org/0000-0001-5732-5007
authors.initials: AC
authors.lastname: Swanepoel
authors.affiliation: Department of Physiology, School of Medicine, Faculty of Health Sciences, University of Pretoria, South Africa.
authors.forename: Priyaa
authors.initials: P
authors.lastname: Naidoo
authors.affiliation: The Department of Anaesthesiology, The University of Arizona College of Medicine, Tucson, Arizona.
authors.forename: Vance G
authors.initials: VG
authors.lastname: Nielsen
authors.affiliation: Department of Physiology, School of Medicine, Faculty of Health Sciences, University of Pretoria, South Africa.
authors.forename: Etheresia
authors.initials: E
authors.lastname: Pretorius
mesh_terms: D000293:Adolescent; D000328:Adult; D004964:Estriol / Q000502:physiology*; D004970:Estrone / Q000502:physiology*; D005260:Female; D005337:Fibrin / Q000737:chemistry*; D005342:Fibrinolysis; D006801:Humans; D008297:Male; D008593:Menopause; D011247:Pregnancy; D013916:Thrombelastography; D019851:Thrombophilia / Q000503:physiopathology*; D013927:Thrombosis / Q000188:drug therapy / Q000517:prevention & control; D055815:Young Adult
chemical_list: D004970:Estrone; D005337:Fibrin; D004964:Estriol
keywords: estriol; estrone; hypercoagulability; menopausal hormone therapy; venous thrombosis