Biodegradable, Self‐Reinforcing Vascular Grafts for In Situ Tissue Engineering Approaches

Abstract

Clinically available small‐diameter synthetic vascular grafts (SDVGs) have unsatisfactory patency rates due to impaired graft healing. Therefore, autologous implants are still the gold standard for small vessel replacement. Bioresorbable SDVGs may be an alternative, but many polymers have inadequate biomechanical properties that lead to graft failure. To overcome these limitations, a new biodegradable SDVG is developed to ensure safe use until adequate new tissue is formed. SDVGs are electrospun using a polymer blend composed of thermoplastic polyurethane (TPU) and a new self‐reinforcing TP(U‐urea) (TPUU). Biocompatibility is tested in vitro by cell seeding and hemocompatibility tests. In vivo performance is evaluated in rats over a period for up to six months. Autologous rat aortic implants serve as a control group. Scanning electron microscopy, micro‐computed tomography (µCT), histology, and gene expression analyses are applied. TPU/TPUU grafts show significant improvement of biomechanical properties after water incubation and exhibit excellent cyto‐ and hemocompatibility. All grafts remain patent, and biomechanical properties are sufficient despite wall thinning. No inflammation, aneurysms, intimal hyperplasia, or thrombus formation are observed. Evaluation of graft healing shows similar gene expression profiles of TPU/TPUU and autologous conduits. These new biodegradable, self‐reinforcing SDVGs may be promising candidates for clinical use in the future.

Development of 3D printed electrospun vascular graft loaded with tetramethylpyrazine for reducing thrombosis and restraining aneurysmal dilatation

“…In addition to blood clotting, aneurysmal dilation is another disappointing failure after vascular graft transplantation [ 13 , 14 ]. Although polyester artificial vascular grafts offer a route for blood vessel transplantation, they still encounter difficulty in maintaining a stable tubular structure and resistance to arterial pressure during long-term implantation due to their limited mechanical strength, resulting in adverse events such as aneurysmal dilatation [ 15–17 ]. Currently, the development of mechanically reinforced vascular grafts is receiving increasing attention.…”