In vivo guided regeneration of small diameter arteries

The aim of the present study was to develop a prosthetic graft that could perform as a small diameter vascular conduit. We compared hyaluronic acid based tubular scaffold (HYAFF-11™, 1.5x0.2 cm) with same dimension acellular artery grafts. Male Wistar rats weighing 250–350 g were used. A segment of abdominal aorta (1.5 cm) was incised and, in a group of 30 animals, a HYAFF 11™ tube was anastomized. Acellular artery grafts were implanted in a separate group of 30 control animals. Histological, immunohistochemical (antibodies to von Willebrand factor, CD34, vascular endothelial growth factor receptor-2 and to Myosin Light Chain Kinase) and ultrastructural analysis were used to evaluate the results at 5, 15, 30, 60, 120, and 180 days after surgery. Results demonstrated advantages using HYAFF 11™ tube as compared with the use of arterial graft. HYAFF-11™ tube permitted a prompt endothelialization, followed by a sequential regeneration of the other vascular components that leads to a complete vascular wall regeneration after 15 days from surgery, allowing a 95% patency rate. On the contrary acellular graft led to an high rate of aneurismatic dilatation and of occlusion, allowing only a 25% patency rate. Temporariness of the hyaluronic acid tube was another important novel finding: biomaterial was entirely degraded after 4 months from implantation, and after that, a new artery remained to connect artery stumps. In conclusion, hyaluronic acid based tubular scaffold was able to sequentially orchestrate vascular regeneration events needed for very small artery reconstruction.