title: Matrix-dependent adhesion of vascular and valvular endothelial cells in microfluidic channels.
abstract: The interactions between endothelial cells and the underlying extracellular matrix regulate adhesion and cellular responses to microenvironmental stimuli, including flow-induced shear stress. In this study, we investigated the adhesion properties of primary porcine aortic endothelial cells (PAECs) and valve endothelial cells (PAVECs) in a microfluidic network. Taking advantage of the parallel arrangement of the microchannels, we compared adhesion of PAECs and PAVECs to fibronectin and type I collagen, two prominent extracellular matrix proteins, over a broad range of concentrations. Cell spreading was measured morphologically, based on cytoplasmic staining with a vital dye, while adhesion strength was characterized by the number of cells attached after application of shear stresses of 11, 110, and 220 dyn cm(-2). Results showed that PAVECs were more well spread on fibronectin than on type I collagen (P < 0.0001), particularly for coating concentrations of 100, 200, and 500 microg mL(-1). PAVECs also withstood shear significantly better on fibronectin than on collagen for 500 microg mL(-1). PAECs were more well spread on collagen compared to PAVECs (P < 0.0001), but did not have significantly better adhesion strength. These results demonstrate that cell adhesion is both cell-type and matrix dependent. Furthermore, they reveal important phenotypic differences between vascular and valvular endothelium, with implications for endothelial mechanobiology and the design of microdevices and engineered tissues.
authors.affiliation: Department of Mechanical & Industrial Engineering, University of Toronto, 5 King's College Road, Toronto, Ontario, Canada, M5S 3G8.
authors.forename: Edmond W K
authors.initials: EW
authors.lastname: Young
authors.forename: Aaron R
authors.initials: AR
authors.lastname: Wheeler
authors.forename: Craig A
authors.initials: CA
authors.lastname: Simmons
mesh_terms: D000818:Animals; D001011:Aorta / Q000166:cytology*; D002448:Cell Adhesion; D002478:Cells, Cultured; D042783:Endothelial Cells / Q000166:cytology*; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation* / Q000379:methods*; D013314:Stress, Mechanical; D013552:Swine