Preliminary Study into Visualization Modalities of von Willebrand Proteolysis in Response to Applied Shear

Open Access
- Author:
- Scanlon, Matthew P
- Area of Honors:
- Bioengineering
- Degree:
- Bachelor of Science
- Document Type:
- Thesis
- Thesis Supervisors:
- Dr. Keefe B Manning, Thesis Supervisor
Peter J Butler, Thesis Honors Advisor
Steven Deutsch, Faculty Reader - Keywords:
- von Willebrand Factor
vWF
proteolysis
ventricular assist device
cardiovascular disease
visualization
fluorescence - Abstract:
- Cardiovascular disease (CVD) is the leading cause of mortality around the world. Each year, thousands of patients requiring heart transplants die due to a lack of available organs. One alternative for these patients would be the use of ventricular assist devices (VADs), prosthetic instruments that augment arterial output and help reduce the physical ailments associated with CVD. One particular type of VAD, the axial flow pump, is widely used because of its simple design. Curiously, many patients using these axial pumps experience decentralized bleeding in their joints and gastrointestinal system, a condition known as Acquired von Willebrand Syndrome. It appears that the nonphysiological shear stresses placed on blood by the ventricular assist devices causes a breakdown in the physical structure of von Willebrand Factor (vWF), a multivalent, multimeric blood-borne protein that plays a critical role in coagulation and the repair of vascular damage. This study replicated and extended the experimental design of Dr. Han-Mou Tsai, and, in doing so, more fully elucidated the relationship between shear rate and vWF degradation. The study included the design of a unique, specifically designed flow loop, through which platelet-poor plasma (PPP) was perfused to generate shear rates of known intensity and duration. After perfusion, the PPP was collected and assayed via Western blot coupled with computer imaging software. A major portion of the study was dedicated to establishing the most useful visualization modality for use with Western blotting techniques and refining the staining protocol to improve the quality of the collected images. This study describes the novel Western blotting protocol developed, covers aspects of the protocol that still need to be formulated, as well as the preliminary data collected throughout the development process.