Purpose: The placement of endothelial cells on the surfaces of arteries immediately after vascular interventions has the potential to limit restenosis by inhibiting intimal thickening and by stimulating arterial enlargement. Because such re-endothelialization is dependent on rapid formation of strong endothelial cell-matrix interactions, experiments were performed to identify the extracellular matrix that provided endothelial cells with the greatest resistance to detachment by a shear stress in the least amount of time.
Materials and methods: Rabbit microvascular endothelial cells were plated onto glass slides coated with collagen, laminin, vitronectin, or fibronectin. After allowing 5-45 minutes for cell adhesion, each slide was placed in a parallel plate chamber, and the number of cells present before and after exposure of the cells to shear stresses (1-25 dynes/cm2) were counted.
Results: Endothelial cell retention to the matrix-coated slides was time and matrix dependent. The percentages of endothelial cells retained after adhesion times of 5, 15, 30, and 45 minutes followed by exposure to 15 dynes/cm2 were 9%, 20%, 32%*, and 38%* for collagen; 7%, 20%, 36%*, and 49%* for laminin; 35%, 47%, 62%, and 76%* for vitronectin; and 64%, 58%, 71%, and 78% for fibronectin, respectively (*P < .05 versus 5 minutes adhesion). Similar results were obtained for lower and higher shear stresses, indicating that cell retention was independent of shear stress above 1 dyne/cm2.
Conclusions: The resistance of freshly adherent endothelial cells to detachment by shear stress is matrix- (fibronectin approximately equal to vitronectin > laminin approximately equal to COL) and time-dependent. Fibronectin provided the greatest cell retention in the least amount of time.