Abstract Number: PB1521
Meeting: ISTH 2020 Congress
Background: Upon exposure to non-physiological flow, through disease or implanted medical devices, the excessive cleavage of von Willebrand Factor (VWF) can lead to impaired hemostasis and bleeding.
In this current study, we used a motorized benchtop vortexer as an inexpensive, easy to use tool that requires small sample volume, to study the time-dependent behavior of VWF under various flows conditions.
Aims: Investigate flow patterns within a vortex system and evaluate the effects on VWF structure and function over time.
Methods: VWF was vortexed at three mixer settings in the presence or absence of ADAMTS13 for 0-60 minutes in a 96-well plate. Rotational speeds and flow patterns were determined from captured images using a high-speed camera and evaluated using computational fluid dynamics (CFD). Western blots and multimer analysis were used to investigate VWF structure.
VWF function were assessed by VWF activity, collagen-binding and Ristocetin-induced-platelet-aggregations (RIPA).
Results: Three vortex mixer settings led to laminar (34-rad/s), transitional (112-rad/s), and turbulent flow (150-rad/s), as determined with a high-speed camera and CFD. Turbulent flow lead to cleavage of VWF at lower shear rates than previously reported in cone-and-plate and microfluidic devices under laminar flow (Table 1).
The cleavage and loss of HMWM was observed in samples exposed to turbulent flow with respect to time (Figure 1).
VWF function was impacted after exposure to turbulence for >10 minutes with a time-dependent decrease in antigen levels, VWF activity, collagen binding and RIPA. No significant functional changes were seen in VWF exposed to laminar or transitional flow.
Conclusions: Turbulent flow in the vortex system leads to cleavage of VWF and loss of HMWM over time, correlating with a decreased ability to bind platelets and collagen. Utilizing the vortex system, we can study turbulent flow’s impact on blood, while using small samples, enabling the study of flow features seen in disease and medical devices.
To cite this abstract in AMA style:Ashworth K, Bortot M, Sharifi A, Walker F, Neeves K, Bark D, DiPaola J. Inertial Forces Generated by a Vortex System Promote Cleavage of von Willebrand Factor [abstract]. Res Pract Thromb Haemost. 2020; 4 (Suppl 1). https://abstracts.isth.org/abstract/inertial-forces-generated-by-a-vortex-system-promote-cleavage-of-von-willebrand-factor/. Accessed January 21, 2022.
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