Pericyte-Based Human Tissue Engineered Vascular Grafts: In Vivo Feasibility Assessment

Although autologous vessel grafts are the gold standard for bypass procedures, they are limited by availability in many cases. Current synthetic grafts are not suitable for small-diameter (ID<6mm) vascular applications due to acute thrombosis. While a tissue-engineered vascular graft (TEVG), constructed by incorporating cells within a biodegradable scaffold, seems to be a possible solution to the challenge, its success greatly relies on an appropriate cell source and an efficient cellular delivery and carrier system. Terminally-differentiated vascular cells have poor self-renewal and expansion capabilities, exhibit phenotype switching in culture, and are difficult to harvest in necessary numbers, all of which represent limitations of their use in tissue engineering. Human adult mesenchymal stem cells (MSCs) exhibit multipotentiality and self-renewal capabilities, are more readily available, and therefore could overcome these limitations [1]. Pericytes closely encircle endothelial cells in capillaries. It has been shown that pericytes purified from multiple tissue types displayed multipotentiality, suggesting that they are developmental precursors of MSC [2].