DURABILITY OF CONFLUENT ENDOTHELIAL-CELL MONOLAYERS ON SMALL-CALIBER VASCULAR PROSTHESES INVITRO

  • 1 April 1988
    • journal article
    • research article
    • Vol. 103  (4) , 456-462
Abstract
Since implantation of small-caliber vascular grafts with preformed confluent endothelial cell monolayers (ECMs) may prevent acute platelet deposition and thrombus formation, we have evaluated the conditions necessary to produce durable ECMs. Cultured human umbilical-vein ECs in buffer were attached to vascular grafts - either expanded polytetrafluoroethylene (ePTFE) or knitted Dacron, both with inside diameters of 4 mm - precoated with collagen type I and perfused in vitro with serum-containing culture medium to achieve cell spreading into confluent monolayers. The number of cells attached was quantified by DNA measurements and indium-111 labeling. Morphology was evaluated by scanning electron microscopy. The maximum number of cells that attached acutely was 3.6 .times. 105 cells/cm2 graft and the minimum number needed for confluence was 1.4 .times. 105 cell/cm2 cells/cm2 graft. Confluence was morphologically complete after 2 hours of in vitro perfusion at 15 ml/min. When ECMs were exposed to varying flow rates, cell retention after 1 hour was 96.1% .+-. 5.6% at 50 ml/min, 94.6% .+-. 6.1% at 100 ml/min, 77.6% .+-. 10.8% at 200 ml/min (p < 0.001), and 40.1% .+-. 10.4% at 400 ml/min (p < 0.0001). Confluence was maintained for all grafts exposed to flows of 100 ml/min or less. Fewer cells were retained when acutely attached, unspread cells (71.5% .+-. 11.5%) were compared with established ECMs (89.9% .+-. 6.7%) at a flow rate of 100 ml/min (p < 0.0001). ECMs on knitted Dacron were more durable than on ePTFE (82.7% .+-. 5.3% versus 75.5% .+-. 4.8% remained attached at 200 ml/min, P < 0.05). 111Indium-labeled and unlabelled cells were equivalent with respect to saturation level attachment, spreading time to confluence, and durability under flow at 100 ml/min. We conclude that confluent and durable endothelial cell monolayers can be established on small-caliber vascular grafts within 2 hrs.