Dynamic Perfusion Culture of Human Outgrowth Endothelial Progenitor Cells on Demineralized Bone Matrix In Vitro

BACKGROUND The aim of this study was to investigate the proliferation, differentiation, and tube formation of human outgrowth endothelial progenitor cells (OECs) cultured with porous demineralized bone matrix (DBM) under a dynamic perfusion system in vitro. MATERIAL AND METHODS OECs were isolated, expanded, characterized, eGFP-transfected and seeded on DBM scaffold and cultured under static or dynamic perfusion conditions, and continuously observed under fluorescence microscope. DBM scaffolds were harvested on day six for RT-PCR and western blot assay to analyze the mRNA and protein expression level of CD34, VE-cadherin, and VEGF. Scanning electron microscope (SEM) was used to observe the tube formation of OECs seeded on DBM scaffolds. RESULTS The results showed the cell density of OECs on DBM was higher when exposed to shear stress generated by a dynamic perfusion system. Shear stress also markedly increased the expression level of VE-cadherin and VEGF and decreased the expression of CD34, at both mRNA and protein levels. SEM showed that the shear-stressed OECs formed tube-like structures inside the pores of DBM scaffolds. CONCLUSIONS A dynamic perfusion system can be used as an innovative method for the rapid vascularization in tissue engineering, which can accelerate the proliferation and differentiation of OECs and the vascularization of implanted scaffolds.