A novel perfusion system for the endothelialisation of PTFE grafts under defined flow.

OBJECTIVES: to develop a perfusion system for culturing human endothelial cells on small-diameter PTFE grafts under defined pulsatile shear stress. METHODS: to benefit from a stronger adhesion of endothelial cells to the substrate, we developed a perfusion system which enables culture of endothelial cells on PTFE grafts to confluence under a wide range of shear stress. We also developed an in situ staining method for the determination of the endothelialisation stage by upper light microscopy. RESULTS: the application of pulsatile flow with high shear stress (6.6 dyn/cm2, 5 min) to a graft endothelialised under perfusion did not lead to a disruption of the confluent cell layer. In contrast, a shear stress of 3 dyn/cm2 applied for 5 min was sufficient to wash more than 50% of endothelial cells off the PTFE graft when cultured to confluence under static conditions. CONCLUSIONS: this technique induces a stronger cell adherence of endothelial cells to a PTFE graft in comparison with grafts endothelialised under static conditions. Endothelialised vascular grafts can be pre-conditioned to defined shear stress values.