Luminal surface of pulsatile VAD covered with endothelial cells successfully tested in vivo
A protocol to isolate a pure population of primary endothelial cells from sheep long saphenous veins was developed. The derived endothelial cells were characterized by checking the expression of endothelial specific markers (i.e. VE-cadherin).
In the ensuing phase in-vitro tests were performed to evaluate the functionality of endothelial monolayers of ovine origin using a combined bioreactor mimicking the loading conditions (in terms of wall shear stress and deformation) expected in functioning pulsatile ventricular assist devices (pVADs). Endothelial monolayers were placed on the surface of an elastomeric membrane in contact with a selected geometrical pattern that improves endothelial cell adhesion and functionality.
Based on these protocols and validations, in-vivo experiments in large animals (sheep) were performed (acute conditions, 3-5 hours). Endothelial monolayers were introduced in static conditions to cover the hyperelastic hybrid membrane in the new pVAD that was actuated at increased frequency (multiples of the heart rate) allowing for a decreased stroke volume.
The reconstituted tissue was fully retained upon pump actuation in vivo and no signs of luminal thrombosis were detected in the end-point analysis.