Implantation of amniotic membrane as a vascular substitute in the external jugular vein of juvenile sheep

ObjectiveAmniotic membrane, as a natural biomaterial, has many advantages, such as low immunogenicity, anti-inflammation, antifibrosis, and rich extracellular matrix components, which make it a promising source for vascular tissue engineering. This study assessed the feasibility of constructing a vein conduit from the amniotic membrane and implanting it in the external jugular vein of juvenile sheep.MethodsHuman amniotic membrane was prepared using fresh human placenta. For construction of a tube such as a vein, the membrane was rolled around a tube and amniotic membrane-constructed conduits were interposed to the external jugular vein by end-to-end anastomosis. Grafts were assessed for patency at weeks 5 and 48 and explanted for evaluation with histologic and microscopic techniques.ResultsAt 5 weeks after implantation, the grafts were completely patent and displayed no signs of dilation. The internal surface was smooth and shiny, without any evidence of thrombus formation. After 48 weeks, grafts were still completely patent and displayed no signs of intimal thickening, dilation, or stenosis. No inflammation or fibrosis was evident. Histologic evaluation of the explanted grafts demonstrated a monolayer of endothelial cells. Scanning electron microscopy revealed a confluent layer of cells with normal endothelial cell morphology. A monolayer of cells positive for von Willebrand factor was detected in histology sections.ConclusionsThe findings of this study confirm that the amniotic membrane can be a proper substitute for vascular tissue engineering.

Clinical RelevanceAmniotic membrane is a natural biomaterial that has successfully been used in different fields of surgery. This research evaluated conduit constructed from amniotic membrane as a substitute conduit in the external jugular vein in an animal model. The promising results of this study showed that the amniotic membrane might evolve into a clinically useful alternative for patients lacking vein for vascular reconstructions.