Arterial Decellularized Scaffolds Produced Using an Innovative Automatic System

Abstract

There is still an unmet clinical need for small-caliber artery substitution. Decellularized scaffolds in tissue engineering represent a promising solution. We have developed an innovative system for the automatic decellularization of blood vessels, used to process pig arteries. The system is able to automatically drive a decellularization process in a safe and reliable environment, with complex time patterns, using up to three different decellularization solutions, and providing at the same time a physical stress to improve the decellularization. The decellularization of pig arteries was evaluated by means of histology, DNA quantification and mechanical testing. Outcomes showed scaffolds with no cellular or nuclear remnants and a well-preserved tissue structure, corroborated by mechanical properties similar to native tissue. Decellularized scaffolds were seeded on the inner layer with human endothelial cells and implanted as iliac artery replacement in 4 pharmacologically immune-compromised pigs. This chimeric model was performed as a very preliminary evaluation to investigate the performances of these scaffolds in vivo, and to investigate the fate of seeded cells. Recipients were sacrificed on day 14 and day 70 after surgery, and vessels were found to be patent and with no evidence of thrombi formation. The inner layer was covered by endothelial cells, and the migration of cells positive for α-smooth-muscle actin was observed from the outer layer towards the tunica media. Intriguingly, the endothelial cells on explanted vessels were entirely derived from the host while the seeded cells were lost. In conclusion, this work presents a novel tool for a safe and controlled production of arterial scaffolds, with good decellularization outcomes and a good performance in a short-term, large-animal implantation.

Shear-resistant hydrogels to control permeability of porous tubular scaffolds in vascular tissue engineering

“…Pure wadding (Ø = 5.000 mm, th = 1.650 mm, l = 6.500 mm) was considered as negative control, while DSA (carotid) (Ø = 3.000 mm, th = 0.674 mm, l = 6.500 mm), and tubular electrospun pure silk fibroin (Ø = 3.5 mm, th = 0.300 mm, l = 6.500 mm, produced by Leonardino s.r.l.) were selected as positive references, since they are commonly used for VTE applications [49,50].…”

Cell-free vascular grafts: Recent developments and clinical potential

“…Additionally, studies have shown that they are highly susceptible to intimal hyperplasia at the sites of anastomosis 67,68 . The current challenges facing synthetic grafts may be attributed to the mismatches in mechanical properties — specifically compliance — between the native and synthetic vessels and the surface chemistry that governs important cellular functions such as infiltration and proliferation 69,70 . Alternatively, decellularization of biological tissues yields scaffolds that closely resemble native ECM in composition and micro-anatomical structure, and are therefore more suitable for vascular grafting.…”

“…Subsequently, the decellularized scaffolds may be seeded with cells, or functionalized with biological factors and implanted in vivo. In an attempt to optimize decellularization and ensure consistency of the final product, various groups have opted to automate the process by developing relatively simple devices that integrate all the desired chemical and/or physical processes and may involve several cycles and the use of different solvents 70–72 . These steps are described in more detail below.…”

“…However, some residual DNA was still present in the tissues. A subsequent study optimized the device further to provide longitudinal and radial strain under sterile conditions using two pumps, a heat exchanger and a microcontroller-based unit 70 . Vascular grafts produced with this device were seeded with human iliac artery endothelial cells (hIAEC), and implanted in the iliac arteries of pigs where they remained patent for up to 70 days post-implantation.…”

Harnessing Human Decellularized Blood Vessel Matrices and Cellular Construct Implants to Promote Bone Healing in an Ex Vivo Organotypic Bone Defect Model

“…In the context of decellularized vessel grafts, few studies have tested the potential regenerative capacity of such grafts within in vivo or clinical scenarios . Furthermore, there is a paucity of clinical data regarding the efficacy of decellularized whole organ transplantation .…”