Ultralarge multimers of von Willwbrand factor (VWF) and ADAMTS-13 activity in plasma from BALB/C and C57Bl/6J mice at physiological conditions

SANCHEZ LUCEROS , ANALÍA; KEMPFER, ANA C; FARÍAS, CRISTINA; AMARAL MARÍA M; PIAZZÓN, ISABEL; NEPOMNASCHY, IRENE; LAZZARI MARÍA A

Sydney

Congreso; XX CONGRESS. THE INTERNATIONAL SOCIETY ON THROMBOSIS AND HAEMOSTASIS AND 51st ANNUAL SSC METTING; 2005

THE INTERNATIONAL SOCIETY ON THROMBOSIS AND HAEMOSTASIS

Ultralarge Multimers of Von Willebrand Factor (VWF) And ADAMTS13 Activity In Plasma From BALB/C And C57Bl/6J Mice At Physiological Conditions Abstract number: P0388 Sánchez-Luceros A, Kempfer AC, Farías CE, Amaral MM, Piazzón I, Nepomnaschy I, Lazzari MA Introduction: Mouse model is interesting to study VWF and ADAMTS13 relationship and to evaluate different factors that could affect the balance between them. Animals, material and methods: We studied 51 BALB/c mice (41 female, 10 male) y 33 C57Bl/6J mice (21 female, 12 male); 44 females were virgins (17 multiparous). One mouse was studied during pregnancy. Methods: VWF:Ag (Taylor, 1988). ADAMTS13 (Furlan, 1998; Gerritsen, 1999), ULVWF (densitometrical scanning). Results: Table 1 includes means and standard deviations of VWF:Ag, ADAMTS13 y ULVWF (U/dL)) in BALB/c (A), C57Bl/6J (B) mice and normal human (C). There were no differences by sex neither for parity. The mean of ADAMTS13 was slightly lower in C57Bl/6J mice (P= 0.07). 87% of mice showed an increase in plasmatic ULVWF. The pregnant mouse showed no differences in laboratory values respect the entire group of mice (VWF:Ag: 15 U/dL, ADAMTS13: 46 U/dL). A: n Mean ± SD B: n Mean ± SD C: n Mean ± SD VWF:Ag 37 16 ± 9 18 13 ± 9 27 104 ± 41 ADAMTS13 36 36 ± 15 18 29 ± 10 18 95 ± 37 ULVWF 16 32 ± 12 8 35 ± 10 18 2 ± 7 Ratio VWF/ADAMTS13 0.5 ± 0.38 1.51 ± 0.63 Conclusions: Mice showed an increase of plasmatic ULVWF levels, with low ADAMTS13 activity. There were no differences by sex neither for parity. However, the ratio VWF/ADAMTS13 in mice was lower than in human (P < 0.001), at least in the system used to measure VWF and ADAMTS-13 parameters (over human VWF). This finding appears as a characteristic of this species, not from any particular strain. As it was suggested in dogs and pigs (Sanders, 1995), the low plasmatic VWF would compensate the lower proteolysis, without thrombotic microangiopathic consequences.