Features of remodeling of newly formed vascular tissue based on biodegradable vascular prostheses implanted in the carotid artery of sheep: morphogenetic analysis

Abstract

Tissue-engineered vascular prostheses developed for prosthesis of small-diameter arteries have high biocompatibility and coverage of their patency after implantation into the vascular bed, and should also show a high probability of forming on their basis a newly formed tissue that is largely susceptible to native vascular tissue.Aim: To evaluate the expected patency of biodegradable vascular prostheses with athrombogenic drug coating in large laboratory animal models.Material and Methods. Vascular prostheses Ø 4 mm were fabricated by electrospinning from a polymer composition of 5% polyhydrosibutyrate/valeriate (PHBV) and 10% polycaprolactone (PCL) and a complex of proangiogenic tissues (GFmix): vascular endothelial growth (VEGF), rare fibroblast growth (bFGF) and chemoattractant molecule (SDF-1α). To induce thromboresistant properties of grafts, an athrombogenic modification of the surface of parts of the fabricated prostheses with heparin and iloprost was carried out. Modified prostheses were implanted in the carotid artery for a period of 12 months. The group with autoarterial implantation acted as a control.Results. In 12 months after implantation, the patency of auto-arterial grafts was 87.5%. The patency of PHBV/PCL/GFmix with heparin and iloprost reached 50% at the time of implantation. The biodegradable frame made of reinforced prostheses was almost completely resorbed with the formation of aneurysms throughout. In the modified prostheses, the main elements of the newly formed vascular tissue are present. There is no formation in the walls of the prostheses.Conclusion. The results showed that biodegradable vascular prostheses PHBV/PCL/GFmixHep/Ilo  have a high final patency, which allows us to consider them suitable for the formation of newly formed vascular tissue on their basis. However, due to the aneurysm formation, a long-term execution of the bone tissue of the prosthesis and the thrombogenic properties of the inner surface are required.