Fibrin-polylactide-based tissue-engineered vascular graft in the arterial circulation

There is a clear clinical requirement for the design and development of living, functional, small-calibre arterial grafts. Here, we investigate the potential use of a small diameter, tissue-engineered artery in a pre-clinical study in the carotid artery position of sheep. Small-calibre ( approximately 5 mm) vascular composite grafts were molded using a fibrin scaffold supported by a poly(L/D)lactide 96/4 (P(L/D)LA 96/4) mesh, and seeded with autologous arterial-derived cells prior to 28 days of dynamic conditioning. Conditioned grafts were subsequently implanted for up to 6 months as interposed carotid artery grafts in the same animals from which the cells were harvested. Explanted grafts (n = 6) were patent in each of the study groups (1 month, 3 months, 6 months), with a significant stenosis in one explant (3 months). There was a complete absence of thrombus formation on the luminal surface of grafts, with no evidence for aneurysm formation or calcification after 6 months in vivo. Histological analyses revealed remodeling of the fibrin scaffold with mature autologous proteins, and excellent cell distribution within the graft wall. Positive vWf and eNOS staining, in addition to scanning electron microscopy, revealed a confluent monolayer of endothelial cells lining the luminal surface of the grafts. The present study demonstrates the successful production and mid-term application of an autologous, fibrin-based small-calibre vascular graft in the arterial circulation, and highlights the potential for the creation of autologous implantable arterial grafts in a number of settings.