Coronary artery bypass grafting is currently one of the most effective procedures for the treatment of advanced ischemic heart disease. However, the availability of suitable vascular conduits remains a significant clinical challenge. Autologous grafts, such as the saphenous vein or the internal mammary artery, are not always usable, while synthetic substitutes show important limitations, especially in small-diameter vessels. In this context, vascular tissue engineering is exploring increasingly sophisticated biomimetic solutions, including tubular scaffolds based on silk fibroin.
This type of scaffold is designed to reproduce the three-dimensional structure of native blood vessels. Their diameter, wall thickness, and degree of porosity can be precisely modulated, allowing the diffusion of nutrients and oxygen and promoting cellular colonization. The goal is to create a temporary framework that guides the organization of vascular cells—endothelial and smooth muscle cells—until the formation of a functional tissue.
Increasingly advanced fabrication techniques
The construction of tubular fibroin scaffolds exploits different technologies, such as electrospinning, casting on cylindrical molds, and combinations with physical or chemical cross-linking processes. Electrospinning, in particular, makes it possible to obtain oriented nanometric fibers capable of mimicking the extracellular matrix of natural vessels. This approach improves cell adhesion and promotes cellular alignment, a crucial aspect for the mechanical functionality of the vessel.
One of the main advantages of fibroin scaffolds compared to traditional synthetic grafts is their ability to support rapid endothelialization. The formation of a continuous endothelial layer on the inner surface of the conduit is essential to prevent thrombosis and restenosis. Fibroin, when appropriately modified or functionalized with bioactive peptides, promotes endothelial cell adhesion and proliferation, significantly reducing the risk of clot formation.
Unlike non-degradable materials, fibroin scaffolds are designed to gradually degrade over time, leaving space for newly formed tissue. This in vivo remodeling process allows better integration with the host tissue and the progressive acquisition of biomechanical properties typical of natural blood vessels. Preclinical studies have shown a limited inflammatory response and good long-term structural continuity.
Applications in coronary bypass surgery
In the context of coronary bypass surgery, fibroin-based bioartificial vessels represent a promising alternative to synthetic grafts, especially for small-diameter vessels, where conventional materials fail more frequently. The possibility of creating “custom-made” conduits, potentially pre-seeded with the patient’s own autologous cells, opens the way to safer and longer-lasting interventions, reducing postoperative complications.
Despite encouraging results, the path toward large-scale clinical application is not yet complete. Further optimization is needed in the standardization of production processes, sterilization methods, and long-term validation through controlled clinical studies. What is currently happening is that the integration of fibroin with other biomolecules, the use of dynamic bioreactors, and the personalized medicine approach are accelerating progress in this field.
Tubular fibroin scaffolds embody a new philosophy in the design of vascular substitutes: no longer simple passive conduits, but bioactive structures capable of interacting with the body. If the promises of research are confirmed in clinical practice, these bioartificial blood vessels could radically transform the future of coronary bypass surgery, offering more natural, safer, and longer-lasting solutions for millions of patients.
