Current Progress in Vascular Engineering and Its Clinical Applications

Abstract

Coronary heart disease (CHD) is caused by narrowing or blockage of coronary arteries due to atherosclerosis. Coronary artery bypass grafting (CABG) is widely used for the treatment of severe CHD cases. Although autologous vessels are a preferred choice, healthy autologous vessels are not always available; hence there is a demand for tissue engineered vascular grafts (TEVGs) to be used as alternatives. However, producing clinical grade implantable TEVGs that could healthily survive in the host with long-term patency is still a great challenge. There are additional difficulties in producing small diameter (<6 mm) vascular conduits. As a result, there have not been TEVGs that are commercially available. Properties of vascular scaffolds such as tensile strength, thrombogenicity and immunogenicity are key factors that determine the biocompatibility of TEVGs. The source of vascular cells employed to produce TEVGs is a limiting factor for large-scale productions. Advanced technologies including the combined use of natural and biodegradable synthetic materials for scaffolds in conjunction with the use of mesenchyme stem cells or induced pluripotent stem cells (iPSCs) provide promising solutions for vascular tissue engineering. The aim of this review is to provide an update on various aspects in this field and the current status of TEVG clinical applications.

Three dimensional (bio)printing of blood vessels: from vascularized tissues to functional arteries

“…Blood vessels are composed of three concentric layers: the inner, middle, and outer layers [59,60]. As can be seen from figure 1, the innermost layer, tunica intima, is composed of non-thrombogenic monolayer endothelial cells [61,62]. These endothelial cells prevent and modulate platelet activity and thrombus formation by secreting particular chemicals such as nitric oxide [63,64].…”

Mitigating challenges and expanding the future of vascular tissue engineering—are we there yet?

“…Thrombosis is an important defense mechanism to combat bleeding, but it also imposes a meaningful obstruction to developing tissue-engineered grafts. Thrombogenicity is also a critical factor in determining the biocompatibility of vascular grafts and the viability of vascular trees within complex organs ( Jouda et al, 2022 ). For instance, the effects of thrombosis can be amplified when various synthetic grafts are used as vascular access devices for hemodialysis due to their low patency rates.…”

Spherical rotary cell seeding system for production of small-caliber tissue-engineered blood vessels with complex geometry

“…Through model refinement, it is now possible to produce patient-derived tissue-engineered blood vessels (TEBV) with defined genetic backgrounds to better understand the pathobiology behind vascular diseases 3 , 4 . Different techniques to generate TEBVs have been developed over the years, each showcasing pros and cons, and can be classified in three main categories: (1) vascular conduits made of cells seeded on manufactured scaffolds, (2) vascular conduits made by cell-sheet engineering and (3) bioprinting 5 , 6 . One of the challenges in vascular tissue engineering is still, however, to improve cellular seeding, distribution, and organization to homogeneously incorporate cells onto a tubular structure.…”