Development of a reinforced porcine elastin composite vascular scaffold

Abstract

Elastin, a principal structural component of native arteries, has distinct biological and mechanical advantages when used as a biomaterial; however, its low ultimate tensile strength has limited its use as an arterial conduit. We have developed a scaffold, consisting of a purified elastin tubular conduit strengthened with fibrin bonded layers of acellular small intestinal submucosa (aSIS) for potential use as a small diameter vascular graft. The addition of aSIS increased the ultimate tensile strength of the elastin conduits nine-fold. Burst pressures for the elastin composite vascular scaffold (1,396 +/- 309 mmHg) were significantly higher than pure elastin conduits (162 +/- 36 mmHg) and comparable to native saphenous veins. The average suture pullout strength of the elastin composite vascular scaffolds was 14.612 +/- 3.677 N, significantly higher than the pure elastin conduit (0.402 +/- 0.098 N), but comparable to native porcine carotid arteries (13.994 +/- 4.344 N). Cyclic circumferential strain testing indicated that the composite scaffolds were capable of withstanding physiological loading conditions for at least 83 h. Implantation of the elastin composites as carotid interposition grafts in swine demonstrated its superiority to clinically acceptable ePTFE with significantly longer average patency times of 5.23 h compared to 4.15 h. We have developed a biologically based elastin scaffold with suitable mechanical properties and low thrombogenicity for in vivo implantation, and with the potential for cellular repopulation and host integration reestablishing an appropriate elastic artery.

Modelling the mechanical response of elastin for arterial tissue

“…it depicts an almost linear relation between the pressure and the radius. Interestingly, the pressure-radius response of the neo-Hookean model is compatible with a protective role of collagen and moreover consistent with experimental observations: Hinds et al (2006) tested purified elastin tubular conduits and observed a burst pressure of 162 AE 36 mmHg. Unfortunately, limited experimental data are available that depict the actual pressure-diameter response of purified arterial elastin tubes under inflation, this is due to the tendency of arterial elastinous tubes to form aneurysms and fail near physiological pressures (Lillie, 2009).…”

Extract of fetal membrane would inhibit thrombosis and hemolysis

“…Viscoelasticity is a mechanical feature which is necessary for inhibition of thrombosis and intimal hyperplasia in blood-contacting devices [62]. Viscoelasticity of biomaterials is largely depending on amount of elastin [63]. The AM has proper viscoelasticity to be employed in biomedical engineering [10].…”

New Developments in Tissue Engineering of Microvascular Prostheses

“…Other studies examine the use of SIS (Small Intestinal Submucosa), already amply employed in clinical management of wounds. These studies show the good mechanical properties of this biomaterial (Hinds MT et al 2006), but also the poor long-term patency of conduits (Pavcnik D et al 2009).…”