Vascular implants – new aspects for in situ tissue engineering

Abstract

Conventional synthetic vascular grafts require ongoing anticoagulation, and autologous venous grafts are often not available in elderly patients. This review highlights the development of bioartificial vessels replacing brain-dead donoror animal-deriving vessels with ongoing immune reactivity. The vision for such bio-hybrids exists in a combination of biodegradable scaffolds and seeding with immune-neutral cells, and here different cells sources such as autologous progenitor cells or stem cells are relevant. This kind of in situ tissue engineering depends on a suitable bioreactor system with elaborate monitoring systems, three-dimensional (3D) visualization and a potential of cell conditioning into the direction of the targeted vascular cell phenotype. Necessary bioreactor tools for dynamic and pulsatile cultivation are described. In addition, a concept for design of vasa vasorum is outlined, that is needed for sustainable nutrition of the wall structure in large caliber vessels. For scaffold design and cell adhesion additives, different materials and technologies are discussed. 3D printing is introduced as a relatively new field with promising prospects, for example, to create complex geometries or micro-structured surfaces for optimal cell adhesion and ingrowth in a standardized and custom designed procedure. Summarizing, a bio-hybrid vascular prosthesis from a controlled biotechnological process is thus coming more and more into view. It has the potential to withstand strict approval requirements applied for advanced therapy medicinal products.

Shear Stress Induces a Time-Dependent Inflammatory Response in Human Monocyte-Derived Macrophages

“…Acellular vascular implants have been a promising approach for replacing small-diameter arteries. These biodegradable scaffolds promote new tissue formation, cellular infiltration, and ECM deposition [66]. However, the rate of scaffold degradation heavily influences patient outcomes.…”

Biological Materials for Tissue-Engineered Vascular Grafts: Overview of Recent Advancements

“…Different cell lines and sources have been evaluated over time, both from primary commercial human lines—mainly used for basic research purposes—or stem cells isolated from different tissues. However, problems can arise from the tissue used for stem cell source isolation and in the amount of cells isolated, which is often unsatisfactory [ 19 , 29 ].…”

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

“…This essential characteristic is required to support gas diffusion, nutrient supply, and removal of waste that can sustain tissues and organs. However, integrating individual grafts into existing vascular networks represents a significant challenge ( Traore and George, 2017 ; Meng et al, 2021 ; Blume et al, 2022 ). Specifically, scaffolds fail to fully reproduce the native organization of the microvascular tree in tissue-engineered grafts ( Vajda et al, 2021 ).…”