Generation of three-dimensional vascular graft from umbilical cord pericytes using cell sheet engineering

In the case of limited accessibility of the autologous vessels and the disadvantages of synthetic scaffolds, small-diameter vascular grafts (SDVG) made from cellularized natural scaffolds are needed for the treatment of coronary artery diseases. The aim of this thesis is to generate three dimensional SDVG model. For this purpose, CD146+ pericytes were isolated from human umbilical cord vein (HUCV) and differentiated into smooth muscle cells (SMCs) and fibroblasts. They were combined with collagen type I/elastin/dermatan sulfate and collagen type I/fibrin to form tunica media and adventitia respectively. To generate tunica intima-like layer, HUCV endothelial cells (ECs) were seeded on the construct by cell sheet engineering method after fibronectin and heparin coating. Anti-thrombogenic property of intima layer was shown by adhesion test with thrombocyte differentiated from human cord blood CD34+ cells. Characterization of the vascular construct was performed by immunolabeling, histochemical staining and scanning and transmission electron microscopy (SEM and TEM). SEM and TEM analysis of vascular construct revealed the presence of three histologic tunicae. The VEGFR-1 expressing ECs in tunica intima; α-SMA expressing SMCs in tunica media and the tenascin expressing fibroblasts in tunica adventitia were detected by immunolabeling. This thesis will provide a preliminary blood vessel model by combining natural scaffolds and vascular cells differentiated from pericytes for generation of fully natural SDVG.