Endothelial Progenitor Cell Rolling and Capture On Biomaterial Surfaces

Monday, November 8, 2010: 9:30 AM
255 C Room (Salt Palace Convention Center)
Wen Jun Seeto, Jordan T. Hamilton and Elizabeth A. Lipke, Department of Chemical Engineering, Auburn University, Auburn University, AL

Endothelial progenitor cells (EPCs) have the potential to become a reliable source of autologous cells for endothelialization of intravascular devices and vascularization of tissue engineered constructs. In this project, we have characterized the rolling and capture of EPCs on different protein-coated surfaces using a parallel plate flow chamber. These results will be applied in the design of future biomaterial surfaces to enhance endothelialization and improve EPC strength of adhesion under shear stress. EPCs are blood-derived cells and little is currently known about their response to shear stress.  For these studies, umbilical cord blood outgrowth endothelial colony forming cells (ECFCs) were used.  ECFCs were first expanded in culture.  To assess ECFC ability to interact with our material coatings under shear stress, ECFCs were dissociated and suspended in flow media. Using a Glycotech parallel plate flow chamber, the ECFC cell suspension was sheared over collagen-coated tissue culture polystyrene (TCPS), gelatin-coated TCPS and CellBIND surfaces with shear rates of 40s-1, 80s-1, and 120s-1. Tethering of ECFCs was shown to relate to shear rates and adhesion material surface. Transient adhesion of ECFCs occurs more frequently on collagen-coated TCPS than the other two adhesion material surfaces. Migration of ECFCs on these surfaces under both static and shear conditions was also studied. We have also studied the adhesion and spreading of EPCs and polyethylene glycol diacrylate (PEG-DA) hydrogels with covalently coupled Arg-Gly-Asp-Ser (RGDS). Future studies will investigate the role of specific integrin binding sites in ECFC rolling and capture under shear stress.  Capture of rolling ECFCs could be maximized by engineering biomaterials to incorporate the appropriate binding ligands. Our results provide a better understanding of ECFCs-material interactions under physiological shear stress and will aid in the design of materials for stent coating and vascular grafts as well as for other intravascular applications.

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