Back
A MURINE MODEL TO ASSESS VON WILLEBRAND FACTOR FUNCTION IN VIVO
Abstract number: O-W-015
Marx1 I., Lenting2 P.J., Pendu2 R., Christophe1 O.D., Denis1 C.V.
11Unite 770, INSERM, Le Kremlin Bicetre, France 22Dept. of Clinical Chemistry & Haematology, University Medical Center, Utrecht, Netherlands
How-to-cite Marx I, Lenting PJ, Pendu R, Christophe OD, Denis CV. A MURINE MODEL TO ASSESS VON WILLEBRAND FACTOR FUNCTION IN VIVO. J Thromb Haemost 2007; 5 Supplement 2: O-W-015
Abstract
Introduction: Von Willebrand Factor (VWF) structure-function relationship has been studied only through in vitro approaches. The VWF-deficient (VWF-/-) mouse model is useful to examine the in vivo function of VWF but does not allow a subtler analysis of the relative importance of its different domains.
Methods: To study the physiological importance of particular VWF domains in an experimental in vivo model, we have introduced point mutations into murine VWF (mVWF) cDNA that inhibit VWF binding to glycoprotein (Gp) Ib (K1362A), to GpIIbIIIa (D2509G) and to fibrillar collagen (D1742A, S1783A, H1786A). We delivered wild type (wt) or mutated mVWF plasmid DNA driven by a CMV promoter into VWF-/- mice using hydrodynamic tail vein injection and assessed whether hemorrhagic symptoms could be corrected.
Results: Hydrodynamic gene transfer resulted in maximum expression of mVWF 24H after injection with levels reaching saturation for 50mg of mVWF cDNA (43863% of VWF expression). Factor VIII activity was normalized in VWF-/- mice injected with mVWF cDNA. Multimer analysis from VWF-/- mice injected with mVWF plasmid revealed multimerisation with a decrease in high multimers compared to wt mice. Bleeding time (BT) was corrected after injection of wt mVWF cDNA in VWF-/- mice (16568 sec), whereas non-injected mice did not stop bleeding. However BT stayed slightly prolonged compared to wt mice (7512 sec). Injection of the GpIIbIIIa and the collagen binding mutants in VWF-/- mice also resulted in a correction of BT, with values of 18960 sec and 13956 sec respectively. In contrast, mice injected with the GpIb binding mutant were bleeding for as long they were observed (>600s) although the volume of blood lost was decreased compared to non-injected mice (6523 ml vs 19440 ml).
Conclusions: These results show that mutations affecting VWF binding to GpIIbIIIa or to collagen are not resulting in bleeding symptoms in vivo. Our model allows the rapid in vivo evaluation of specific mutations on VWF hemostatic function.
To cite this abstract use the following format:
Journal of Thrombosis and Haemostasis 2007; Volume 5, Supplement 2: abstract number
Session Details
| Date: |
01/08/2007
|
| Time: |
00:00-00:00
|
| Session name: |
XXIst ISTH Congress |
| Subject: |
|
| Location: |
Oxford, UK |
| Presentation type: |
|
| Back to top |
|
