Promotion of adhesion and proliferation of endothelial progenitor cells on decellularized valves by covalent incorporation of RGD peptide and VEGF.

Tissue engineered heart valve is a promising alternative to current heart valve surgery, for its capability of growth, repair, and remodeling. However, extensive development is needed to ensure tissue compatibility, durability and antithrombotic potential. This study aims to investigate the biological effects of multi-signal composite material of polyethyl glycol-cross-linked decellularized valve on adhesion and proliferation of endothelial progenitor cells. Group A to E was decellularized valve leaflets, composite material of polyethyl glycol-cross-linked decellularized valves leaflets, vascular endothelial growth factor-composite materials, Arg-Gly-Asp peptide-composite materials and multi-signal modified materials of polyethyl glycol-cross-linked decellularized valve leaflets, respectively. The endothelial progenitor cells were seeded for each group, cell adhesion and proliferation were detected and neo-endothelium antithrombotic function of the multi-signal composite materials was evaluated. At 2, 4, and 8 h after the seeding, the cell numbers and 3H-TdR incorporation in group D were the highest. At 2, 4, and 8 days after the seeding, the cell numbers and 3H-TdR incorporation were significantly higher in groups C, D, and E compared with groups A and B (P < 0.05) and cell numbers and the expression of t-PA and eons in the neo-endothelium were quite similar to those in the human umbilical vein endothelial cells at 2, 4, and 8 days after the seeding. The Arg-Gly-Asp- peptides (a sequential peptide composed of arginine (Arg), glycine (Gly) and aspartic acid (Asp)) and VEGF-conjugated onto the composite material of PEG-crosslinked decellularized valve leaflets synergistically promoted the adhesion and proliferation of endothelial progenitor cells on the composite material, which may help in tissue engineering of heart valves.