Effectiveness of Using Endothelial Colony-Forming Cells for Creating Tissue-Engineered Vascular Grafts under in vitro Conditions

The aim of the investigation was to assess the effectiveness of using endothelial colony-forming cells (ECFCs) for populating polymer vascular grafts under the conditions of a pulsatile bioreactor.

Materials and Methods. Grafts were fabricated by electrospinning from mixture of poly(3-hydroxybutyrate-co-3-hydroxyvalerate), poly(ε-caprolactone), and type I collagen. To carry out the experiments, a commercial culture of the primary human coronary artery endothelial cells (HCAEC), a culture of the human umbilical vein endothelial cells (HUVEC), and ECFCs obtained from the peripheral blood of patients with IHD have been used. A suspension of the cells at a concentration of 700,000 per ml was introduced into the grafts, cultivated for 2 days under static conditions, then in the pulsatile reactor at shear stress of 1.27 dyn/cm² for 1 day, and at 2.85 dyn/cm² for another 5 days. The graft luminal surface underwent immunofluorescent staining for detecting CD31, VEGFR-2, CD144, vWF, F-actin markers and type IV collagen, after that, cell density was also calculated on 1 mm² of the graft surface.

Results. Changes signifying their adaptation to shear stress have been registered in all cell cultures during culturing under dynamic conditions. They manifested themselves in intensified expression of the specific markers (VEGFR-2), increased secretory activity with regard to vWF and type IV collagen, ordered F-actin filaments and orientation of the cells along the flow, stimulation of intercellular junction formation. However, inevitably, the cells were partially washed off from the graft surface. The analysis of cellular layer density after dynamic cultivation allowed us to conclude that ECFCs had the strongest adhesion to the polymer and resistance to washing away with a flow.

Conclusion. ECFCs may be recognized to be the most promising culture for populating tissue-engineered vascular grafts owing to the possibility of being isolated from a readily available source (peripheral blood) and demonstrated good adaptation to the conditions of dynamic cultivation. However, significant reduction of cellular layer density caused by shear stress speaks of insufficient adhesion of the cells to the surface and requires further investigations to optimize a feeder layer covering the surface of a polymer scaffold.

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Velikanova E.A., Matveeva V.G., Krivkina E.O., Sevostianova V.V., Khanova M.Yu., Kudryavtseva Yu.A., Antonova L.V. Effectiveness of Using Endothelial Colony-Forming Cells for Creating Tissue-Engineered Vascular Grafts under in vitro Conditions. Sovremennye tehnologii v medicine 2019; 11(4): 44, https://doi.org/10.17691/stm2019.11.4.05