Tissue-Engineered Vascular Graft of Small Diameter Based on Electrospun Polylactide Microfibers.

P V Popryadukhin,G Yu Yukina,V N Vavilov,G I Popov,E M Ivan'Kova,V E Yudin,I P Dobrovolskaya

doi:10.1155/2017/9034186

Abstract

Tubular vascular grafts 1.1 mm in diameter based on poly(L-lactide) microfibers were obtained by electrospinning. X-ray diffraction and scanning electron microscopy data demonstrated that the samples treated at T = 70°C for 1 h in the fixed state on a cylindrical mandrel possessed dense fibrous structure; their degree of crystallinity was approximately 44%. Strength and deformation stability of these samples were higher than those of the native blood vessels; thus, it was possible to use them in tissue engineering as bioresorbable vascular grafts. The experiments on including implantation into rat abdominal aorta demonstrated that the obtained vascular grafts did not cause pathological reactions in the rats; in four weeks, inner side of the grafts became completely covered with endothelial cells, and fibroblasts grew throughout the wall. After exposure for 12 weeks, resorption of PLLA fibers started, and this process was completed in 64 weeks. Resorbed synthetic fibers were replaced by collagen and fibroblasts. At that time, the blood vessel was formed; its neointima and neoadventitia were close to those of the native vessel in structure and composition.

Highlights

In the modern vascular surgery, the problem of the development of vascular grafts with small diameter still exists
The main methods are the following: obtaining tissue-engineered vascular grafts (TEVG) by layer-by-layer tissue engineering [9,10,11,12,13,14]; production of artificial vessels from granulation tissue [15,16,17,18]; use of decellularized transplants [19,20,21]; obtaining artificial vessels based on tubular bioresorbed polymer grafts [22,23,24,25,26,27]
According to the SEM data, the grafts obtained from PLLA solution by electrospinning consist of microfibers 1.5–4 μm in diameter

Summary

Introduction

In the modern vascular surgery, the problem of the development of vascular grafts with small diameter still exists. Low patency rates of the synthetic prostheses with diameter less than 5 mm are related, first of all, to development of neointimal hyperplasia at anastomosis sites and the absence of endothelial layer on the inner side of prostheses [1,2,3,4]. As for pediatric vascular surgery, it is necessary to repeat reconstructive vascular operations due to the fact that nonresorptive synthetic prostheses cannot grow up and develop with a child organism [7]. Any attempts to create vascular grafts of small diameter by traditional methods were unsuccessful, since thromboses arose inside the grafts over a short period of time [8] because of low blood stream rate in these grafts. The main methods are the following: obtaining tissue-engineered vascular grafts (TEVG) by layer-by-layer tissue engineering [9,10,11,12,13,14]; production of artificial vessels from granulation tissue [15,16,17,18]; use of decellularized transplants [19,20,21]; obtaining artificial vessels based on tubular bioresorbed polymer grafts [22,23,24,25,26,27]

Objectives

Methods

Results

Conclusion