TEXTILES.ORG
The University of Edinburgh, U.K., reports that researchers there have developed a novel, two-stage tissue engineering process intended to create better vascular grafts for use in bypass surgeries. Many cardiovascular diseases ultimately require bypass surgery, whereby a vascular graft is installed to navigate blood flow around a damaged blood vessel.
Currently, autologous grafts are the mainstay of treatment, which generally involves the removal of vessels from the leg, arm or chest to replace faulty cardiac arteries. However, these often confer issues at the donor site and do not possess the mechanical properties required to adequately replace native vessels. Synthetic grafts have limited use in larger-diameter arteries, but for smaller vessels they frequently result in infection or intimal hyperplasia, where thickness is reduced by cell growth inside the lumen.
In recent years, tissue engineering research has turned to 3D bioprinting as a means of developing better graft options. In 2023, the Edinburgh-based research group published a new technique that printed gelatin-based bioinks onto a vertically spinning mandrel. This technique could create high-quality constructs with suitable length and wall thickness but the maximum burst pressure—the amount of pressure the construct could withstand before irreparably bursting—was far inferior to that of natural vessels.
So, in their latest paper, the team presented a novel two-stage tissue engineering method that sees the gelatin-based bioprinted construct reinforced with electrospun nanofibers to create an external wall made of biodegradable polymer. The resulting bi-layered graft construct proved comparable to natural vessels in mechanical strength and burst pressure, making it a viable alternative to autologous grafts.
The two-stage technique can create constructs varying in diameter from 1-40mm, which could, theoretically, be used to replicate a variety of vessels in the heart and elsewhere in the body. The team is seeking to progress their research into animal models in the hopes that the technology will eventually be used to treat human cardiac diseases.