Staged Research and Evaluation of Tissue-Engineered Vascular Implant Based on Bioresorbable Polymer Scaffold for Human Vascular Reconstruction

Abstract

Introduction . A tissue-engineered vascular implant based on a biodegradable polymer scaffold may become an alternative to modern vascular prostheses, because it is free from such shortcomings as low patency rates in small-diameter vascular reconstructions, infection risks, and the absence of aged-related adaptive changes in the recipient’s body. Objective . Staged research and evaluation of the tissue-engineered vascular implant based on a combined polymer scaffold in a long-term chronic in vivo experiment. Materials and Methods . A two-layer bioresorbable scaffold was obtained by electrospinning from poly(Llactide) and poly(ε-caprolactone) fibers. The microstructure (scanning electron microscopy, Supra 55VP-32-49, Carl Zeiss), mechanical properties (Instron 5943 testing machine) and biocompatibility (MTT test) of the samples were studied. At the first stage, the scaffold was implanted into the abdominal aorta of Wistar rats (n=25); the follow-up periods were 1 month (n=3), 2 months (n=4), 3 months (n=6), 6 months (n=6), 12 months (n=2), 18 months (n=2), 24 months (n=2). At the second stage, the posterior vena cava of a Papio hamadryas primate (n=1) was reconstructed; the follow-up period was 29 months. Histology was performed on transverse and longitudinal sections of the implant, stained with hematoxylin and eosin; connective tissue was identified using the Mallory method. Results . The obtained bilayer biodegradable polymer scaffold possesses robust physical and mechanical properties and biocompatibility. In all in vivo experiments, the vascular reconstruction remained patent, with no signs of myointimal hyperplasia in the anastomotic area. The scaffold’s ability to integrate into the vascular bed, forming a new vascular wall, as well as adaptive age-related changes in the reconstruction area in response to recipient growth, was demonstrated. Conclusion . Long-term chronic in vivo experiments demonstrated the safety, biocompatibility, and efficacy of the developed scaffold. The resulting tissue-engineered vascular implant exhibits high patency rates and the ability to undergo adaptive age-related changes.