Developing Human Umbilical Vein as Living Scaffolds for Vascular Tissue Engineering

Abstract

We have previously shown that endothelium-denuded human umbilical veins (HUV) are suitable scaffolds for vascular tissue engineering with contractile properties and endogenous prostacyclin release. This study established efficient methods to denude and seed HUV with allogeneic endothelial cells in a perfusion bioreactor in order to create small caliber vessel grafts. Stress-strain relationships and ultimate failure stresses were determined. The effects of a gas-based denudation method on contractile function, reductive capacity, and histology were evaluated. Finally, denuded HUV were seeded in a perfusion bioreactor to create small diameter vessel grafts. HUV displayed biphasic stress-strain relationships, but higher compliances compared to autologous vessels. Burst pressures extrapolated from the ring failure stresses was approx. 1000 mm Hg. Denudation by dehydration proved to be an effective method at gas flow rates of 60-120 ml/min. Endothelial cells were removed completely, whereas neither basal membranes nor functional properties were affected. Seeding of denuded HUV with endothelial cells in a perfusion bioreactor using suitable rotation patterns resulted in an even cell distribution and a confluent endothelium which was shear-resistant at flow rates up to 40 ml/min. These results indicate that the outlined procedures are suitable components of a protocol to turn HUV into small caliber vessel grafts.