Fabrication of branched hybrid vascular prostheses.

We devised a branched, or bifurcated, hybrid vascular prosthesis that was mainly composed of bovine smooth muscle cells (SMCs) and type I collagen with minimal reinforcement by a knitted fabric mesh made of segmented polyester. The tubular hybrid medial tissue with small (3 mm) or large (6 mm) inner diameter was prepared by pouring a cold mixed solution of SMCs and collagen into a corresponding tubular mold and by subsequent thermal gelation, followed by 7-day culturing. A branched hybrid medial tissue was prepared by an end-to-side anastomosis between these tubes of different sizes. Two-week culture of the branched tissue resulted in continuous tissue formation at the anastomotic site. Upon seeding and culture of bovine endothelial cells (ECs), a fully endothelialized branched hybrid vessel was prepared. Under a continuous pulsatile flow condition, morphological alterations of ECs, responding to local flow dynamics generated by the branched configuration, were seen. Reinforcement with an elastomeric mesh improved mechanical strength of the hybrid tissue and created compliance matching with native arteries. A branched hybrid graft with mesh reinforcement is expected to be applicable to arterial replacement in a branching region.