Potential of von Willebrand Factor for early detection and differentiation of shear related blood damage by blood pumps

 

Background

The von Willebrand Factor (VWF) is our largest soluble protein and essential for the early phase of hemostasis. Under high shear stress that arise in injured vessels, the large VWF-multimers unfold and recruit still inactive platelets to the site of the vascular lesion. This unfolding of VWF also enables its degradation and hence regulates its functionality.

High shear forces are also side effects of ventricular assist devices (VADs). In contrast to an acute injury, VAD-related shear forces continuously lead to pronounced degradation and mechanical demolition and result in loss of functional VWF with an increased bleeding-risk for patients.

Project Aim

Notwithstanding that the shear-related negative effect on VWF is well known, the VWF analysis is not yet taken into account during the verification of blood pumps. Although the VWF reacts generally more sensitive to shear stress than red blood cells, the blood damage profile of VADs is normatively determined by the rate of hemolysis. In this project, we investigate the potential of VWF as early marker for shear-related blood damage and its differentiation.

Methods

For this purpose, we analyze the VWF profile of samples of in-vitro experiments as well as clinic samples of patients undergoing LVAD implantation.

The VWF analysis involves protein-chemical quantification and detection of functionality via enzyme-linked immuno-sorbent assays as well as determination of the VWF-multimers’ profile via electrophoresis.

The methods are optimized regarding effort and costs as well as specified for pig blood, which is used in the in-vitro experiments at LuF CVE.

Partly funded as part of the HOC Surf project	European Union and Land Nordrhein-Westfalen