STATE-OF-THE-ARTERY: DEVELOPING A 3D-PRINTED, PATIENT-SPECIFIC IN VITRO MODEL OF ARTERIOVENOUS FISTULAS TO REPLACE ANIMALS IN ENDOTHELIAL CELL STUDIES
Nasir Shah1,2, Shannon Thomas1,3, Zoltan Endre1,2, Tracie Barber4, Blake Cochran5, Jonathan Erlich1,2 1School of Clinical Medicine, University Of New South Wales, Sydney, NSW, Australia2Department of Nephrology, Prince of Wales Hospital, Randwick, NSW, Australia3Department of Vascular Surgery, Prince of Wales Hospital, Randwick, NSW, Australia4School of Mechanical and Manufacturing Engineering, University of New South Wales, Sydney, NSW, Australia5School of Biomedical Sciences, University of New South Wales, Sydney, NSW, Australia
Abstract
Aim: To use 3D-printing to create patient-specific models of arteriovenous fistulas for vascular research.
Background: Endothelial cell dysfunction is a feature of several medical conditions including chronic kidney disease (CKD). In Australia, 10% of adults have CKD and about 15,000 receive treatment with dialysis. For those treated with dialysis, easy access to the bloodstream is necessary and is best achieved using a surgically-created connection between an artery and vein called an arteriovenous fistula (AVF). Why some AVFs fail to mature and others develop high blood flows is unclear. Standard cell culture provides valuable insight into endothelial cell function, but the flat surface neglects the complex physiology of disturbed blood flow through intricate vessel geometries. The use of animal models is limited by the ethical implications of the interventions, the required surgical skill, an inability to simulate comorbidities, differences in vessel size, breed genetic diversity, and a lack of commercially available reagents.
Methods: Patient AVFs were imaged using a modified ultrasound machine. Specialised segmentation software was used to generate AVF geometries which were 3D-printed using a water-soluble filament. Prints were cast in silicone and dissolved away leaving an AVF-shaped cavity. Human dermal microvascular endothelial cells (HMEC-1) were cultured on the internal surface of these models.
Results: Fabrication of patient-specific models was accurate and reproducible. Immunofluorescence with DAPI and Phalloidin confirmed the presence of a HMEC-1 monolayer on the luminal surface of the models.
Conclusions: This 3D in vitro mimic model overcomes limitations of current cell culture techniques whilst maintaining the 3D geometry that is only seen in animal models. This will allow rapid investigation of endothelial cell signalling in true AVF geometries.
Biography
Dr. Nasir A. Shah is an early career nephrologist and PhD Candidate at the University of New South Wales in Sydney, Australia. Working at the intersection of vascular biology, nephrology, and engineering, his work focuses on high flow arteriovenous fistulas, the endothelial cell signaling that underpins their development, and their relationship with cardiovascular disease. By merging novel additive manufacturing technologies with established biological science techniques, he looks evaluate endothelial cell signalling using an innovative 3D mimic model based off true patient blood vessel geometries. Beyond the molecular basis of high flow fistula formation, he is interested in the cardiovascular implications of vascular access creation.