Reconstruction of Vascular and Urologic Tubular Grafts by Tissue Engineering

Abstract

Tissue engineering is one of the most promising scientific breakthroughs of the late 20th century. Its objective is to produce in vitro tissues or organs to repair and replace damaged ones using various techniques, biomaterials, and cells. Tissue engineering emerged to substitute the use of native autologous tissues, whose quantities are sometimes insufficient to correct the most severe pathologies. Indeed, the patient’s health status, regulations, or fibrotic scars at the site of the initial biopsy limit their availability, especially to treat recurrence. This new technology relies on the use of biomaterials to create scaffolds on which the patient’s cells can be seeded. This review focuses on the reconstruction, by tissue engineering, of two types of tissue with tubular structures: vascular and urological grafts. The emphasis is on self-assembly methods which allow the production of tissue/organ substitute without the use of exogenous material, with the patient’s cells producing their own scaffold. These continuously improved techniques, which allow rapid graft integration without immune rejection in the treatment of severely burned patients, give hope that similar results will be observed in the vascular and urological fields.

A Review: Textile Technologies for Single and Multi‐Layer Tubular Soft Tissue Engineering

“…Capillaries irrigate these organs’ cells, and the veins return the hypoxic blood to the heart for a new cycle of circulation. [ 71 ] The structure of arteries and veins is essentially the same, composed of a three‐layer wall: tunica intima, tunica media, and tunica externa (Figure 9). [ 64,71 ] The inner layer (tunica intima) consists of a smooth layer of endothelial cells.…”

“…[ 71 ] The structure of arteries and veins is essentially the same, composed of a three‐layer wall: tunica intima, tunica media, and tunica externa (Figure 9). [ 64,71 ] The inner layer (tunica intima) consists of a smooth layer of endothelial cells. They form a barrier and prevent permeability between the wall of the blood vessel and the blood.…”

“…The outer layer (tunica adventitia or externa) mainly consists of ECM rich in collagen fibers to secure it in the surrounding tissue and ensure the vessel's mechanical resistance. [ 71 ]…”

“…Depending on the blood vessel type, the specific composition of these vascular layers varies. [ 71 ] Arteries, for example, have a thicker muscular media and a small inner lumen to withstand high arterial blood pressure. [ 64 ] Veins, however, have to withstand low venous blood pressure, which is why their walls are overall thinner and they are less elastic.…”

“…[ 64 ] Veins, however, have to withstand low venous blood pressure, which is why their walls are overall thinner and they are less elastic. [ 71 ] In particular, their media layer contains fewer muscle cells, and the lumen is larger compared to arteries for passive blood flow. In addition to the cellular organization within the wall structure, the ECM, which mainly contains elastic fibers, provides elasticity to the blood vessel for it to expand with increased blood pressure and contract and narrow the lumen, again.…”