Migration of adult human vascular endothelial cells: effect of extracellular matrix proteins.

An ideal vascular prosthetic graft should support rapid endothelial coverage and allow maximal rates of endothelial cell migration on its surface. To study this we modified and developed a method to measure rates of migration of adult human vascular endothelial cells (AHVECs) on test surfaces using an O-ring fence technique. We measured the rates of AHVEC migration on a variety of extracellular matrix proteins of interest because of their ability to support cell attachment. AHVECs, initially constrained in rings with an area of 0.62 cm2 (day 0), were allowed to migrate radially, and area coverage was measured after 7 days. The greatest areas of migration were seen on fibronectin (1.20 cm2) and gelatin (1.29 cm2) when compared with control (polystyrene [0.97 cm2]), p less than 0.01, p less than 0.05. Migration on laminin and prepared extracellular matrix from AHVEC was not statistically different from that of controls. Of extracellular matrix proteins studied in our system, a gelatin substrate in the presence of serum resulted in maximal rates of AHVEC migration.

Use of tritiated thymidine as a marker to compare the effects of matrix proteins on adult human vascular endothelial cell attachment: implications for seeding of vascular prostheses.

We have developed a technique to measure attachment of adult human vascular endothelial cells to test surfaces with tritiated thymidine used as a marker. With this technique, we measured attachment of adult human vascular endothelial cells to a series of extracellular matrix proteins, including fibronectin-coated (10 micrograms/cm2), laminin-coated (10 micrograms/cm2), and collagen-coated (1% gelatin) surfaces because of the role of these proteins in promoting cell attachment and growth. For a typical experiment, in the presence of serum, initial attachment (at 1 hour) was greatest on fibronectin-coated (63%) and gelatin-coated (60%) tissue culture plastic (polystyrene) and was least on laminin-coated (28%) or untreated polystyrene (18%). The data suggest that fibronectin, either alone, or with a more complex combination of extracellular components may need to be present on prosthetic surfaces to produce maximal cell attachment and subsequent growth to confluence in vivo. The described method of measuring attachment is independent of surface properties, ensures complete recovery of cells, and will allow systematic exploration of those properties that best support human endothelial cell attachment to vascular prosthetic surfaces.

Adult human vascular endothelial cell attachment and migration on novel bioabsorbable polymers.

We studied the ability of polymers from which vascular prostheses (VPs) are or could be fabricated to support attachment and migration of adult human vascular endothelial cells (AHVECs) in an in vitro system. Polymers included Mylar, Teflon, two novel bioabsorbable polymers with different biologic half-lives (BR1 and BR2), and an elastic nonabsorbable biocompatible polymer (EBN). Both BR1, BR2, and EBN supported AHVEC attachment well (56%, 62%, and 71%, respectively, of plated cells at one hour, respectively) but differed in their ability to support AHVEC migration. The AHVECs attached less well to Mylar and Teflon (39% and 21%), and in no case were AHVECs observed to grow or migrate on either of these polymers. This finding correlates with the clinical observation that VPs fabricated from Mylar and Teflon uniformly fail to develop an endothelial cell lining after implantation in vivo. Future VPs, fabricated from materials chosen for their ability to support AHVEC attachment, growth, and migration in vitro, might better support a spontaneous endothelial cell lining after implantation in humans.