title: Mural thrombus generation in type 2A and 2B von Willebrand disease under flow conditions.
abstract: To explore the mechanisms that underlie the bleeding tendency in type 2A and 2B von Willebrand disease (VWD), we analyzed the mural thrombus generation process on a collagen surface under physiologic blood flow in a perfusion chamber using whole blood from these VWD patients. At a low shear rate (50 s(-1)), thrombus generation in all type 2A and 2B VWD patients was comparable to that of healthy controls. At a high shear rate (1500 s(-1)), thrombus generation was impaired in all type 2A patients, whereas that in type 2B VWD patients varied from normal to significantly defective, as judged by epifluorescence microscopy of thrombus surface coverage. However, in type 2B patients who showed normal thrombus generation at 1500 s(-1), the height and volume of thrombi was significantly reduced, albeit with the normal surface coverage, compared with control thrombi, and von Willebrand factor (VWF) was poorly distributed within the type 2B thrombus mass when analyzed in detail by confocal laser scanning microscopy. Addition of purified VWF to patient blood completely reversed the defective spatial thrombus growth in type 2B VWD. Thus, our results confirm the impaired thrombus generation in type 2B VWD, which has never been demonstrable in previous in vitro soluble-phase platelet aggregation assays, and point to the critical function of larger VWF multimers in the proper spatial growth of mural thrombi under high shear rate conditions.
authors.affiliation: Department of Pediatrics, Nara Medical University, Kashihara, Japan. sugi-ped@naramed-u.ac.jp
authors.forename: Mitsuhiko
authors.initials: M
authors.lastname: Sugimoto
authors.forename: Hideto
authors.initials: H
authors.lastname: Matsui
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Mizuno
authors.forename: Shizuko
authors.initials: S
authors.lastname: Tsuji
authors.forename: Shigeki
authors.initials: S
authors.lastname: Miyata
authors.forename: Masanori
authors.initials: M
authors.lastname: Matsumoto
authors.forename: Michio
authors.initials: M
authors.lastname: Matsuda
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Fujimura
authors.forename: Akira
authors.initials: A
authors.lastname: Yoshioka
mesh_terms: D001777:Blood Coagulation / Q000187:drug effects; D016022:Case-Control Studies; D003094:Collagen; D019281:Dimerization; D005192:Family Health; D006331:Heart Diseases / Q000097:blood*; D006470:Hemorrhage / Q000209:etiology*; D006801:Humans; D008856:Microscopy, Fluorescence; D008955:Models, Cardiovascular; D010477:Perfusion; D013927:Thrombosis / Q000097:blood*; D014842:von Willebrand Diseases / Q000097:blood / Q000145:classification / Q000150:complications*; D014841:von Willebrand Factor / Q000378:metabolism / Q000494:pharmacology
chemical_list: D014841:von Willebrand Factor; D003094:Collagen