Novel decellularized tissue engineered blood vessel with endothelial progenitor cells for arterial revasculariization

Arterial bypass graft implantation remains the primary therapy for patients with advanced cardiovascular disease. The demand for alternative arterial conduits is due to the poor clinical efficacy of existing synthetic grafts for small-diameter artery applications (<6 mm) and many patients with arterial disease lack adequate saphenous vein. Tissue engineering approaches can be used to generate novel biologically-based conduits for small diameter vascular applications.;The goal of this research was to develop a tissue engineered vessel that could be used as an allograft that can be seeded with autologous endothelial progenitor cells. A tissue engineered vessel was grown from porcine smooth muscle cells that were seeded on a biodegradable scaffold using a biomimetic perfusion system. The tissue engineered vessel was decellularized with detergent solutions to create an allogenic vessel. After decellularization, the vessel had a similar burst pressure to human saphenous vein, significant loss of DNA and cellular proteins, preservation of collagen content (69 +/- 2% of dry weight), and provided a biocompatible matrix that supported cell growth in vitro. Endothelial progenitor cells (EPCs) were isolated from peripheral blood, and the identity of the EPCs was confirmed by morphology, phenotype, and function as compared to endothelial cells (ECs). The decellularized tissue engineered vessels were seeded with EPCs and compared to vessels seeded with ECs for patency in a porcine carotid model with vein grafts as control vascular conduits. The endothelial progenitor EPC seeded vessels and EC seeded vessels remained patent by histology for 30 days in 5 out of 5 implants, whereas the non-seeded vessels occluded in 3 out of 3 implants. The vein grafts were patent in 3 out of 8 implants. Histological analysis demonstrated an endothelium on the explanted tissue engineered vessels, and the residual tissue engineered matrix had cellular infiltration suggesting remodeling of the matrix. The EPC and EC seeded tissue engineered vessels had less neointima (1.3 +/- 0.8 mm²) in comparison to the vein grafts (3.6 +/- 0.6 mm²). These results indicate that a readily available decellularized tissue engineered vessel can be seeded with autologous endothelial progenitor cells to provide a biological vascular graft for therapeutic applications.