Novel tissue-engineered artificial vascular graft model composed from cell, gel, and biodegradable scaffold

Although rapid formation of smooth inner surface is important to construct an artificial vascular graft, a conventional model by using a biodegradable polymer such as poly-glycolic acid, needs long-term culture to form it. In another model by using collagen gel, it is reported that prompt formation of the smooth inner surface could be realized. However, the mechanical property was not suitable, resulting in rupture under a high-pressure condition of arterial level. Therefore, we propose a new artificial vascular graft model constituted of biodegradable polymer, gel, and cells. At first, we manufactured an artificial vascular graft (i.d.5 mm, o.d.7 mm) constituted of poly L-lactic acid (PLLA) with open pore structures by using gas-forming methods. After mixing human normal aortic smooth muscle cells (SMCs) with type I collagen solution, pores of the PLLA scaffold were fulfilled with the mixture. The collagen mixtures were made into gel in the pores of PLLA scaffold incubating at 37°C. The WET-SEM analysis showed that the prompt formation of smooth inner surface was achieved in the new model. Incorporation ratio of SMCs to the artificial vascular graft became approximately 100% by using the cell-collagen mixture, while only 40% of SMCs were trapped in the conventional model where SMCs were inoculated as cell-medium suspension. Therefore, it was suggested that the new artificial vascular graft model, had superior in smooth inner surface formation and cell inoculation, compared with conventional models using either biodegradable polymer or gel.