Researchers based in South Korea and Hong Kong have developed a method to create biomimetic blood vessels by directly 3D printing vascular cells and bioinks containing collagen and vascular tissue extracellular matrix components. The resulting constructs closely mimic natural blood vessels, suggesting that such techniques could pave the way for custom vascular grafts to treat various cardiovascular diseases.
Vascular grafts typically involve removing a healthy blood vessel and implanting it elsewhere to restore blood flow or replace a diseased vessel. However, suitable vessels are not always available, and even if they are, this approach requires their invasive removal.
To address this, researchers have been attempting to develop artificial blood vessels that could be directly implanted into patients who need them. However, to date, developing lab-grown vessels that closely mimic their natural counterparts has proven to be tricky.
“The artificial blood vessel is an essential tool to save patients suffering from cardiovascular disease,” said Ge Gao, a researcher involved in the study. “There are products in clinical use made from polymers, but they don’t have living cells and vascular functions. We wanted to tissue-engineer a living, functional blood vessel graft.”
This research group set out to more closely mimic natural blood vessels by 3D printing vascular cells, including human aortic cells and umbilical vein endothelial cells, in bioinks containing extracellular matrix components that are specific to vascular tissues. The printed bioinks demonstrated increased strength and anti-thrombotic properties, compared with previous materials used to fabricate artificial blood vessels.
The researchers printed artificial vessels, and then cultured them in the laboratory to fine tune their properties, such as their strength, wall thickness, and cellular alignment. So far, the engineered vessels have been tested as abdominal aortic implants in rats, and interestingly, the rats’ own fibroblasts naturally formed a connective tissue layer over the vessels, which looked like an attempt by the body to integrate the implants into the surrounding tissues.
The researchers hope that this technique could pave the way for a successful bioengineered vascular graft in human patients.
Study in Applied Physics Reviews: Tissue-engineering of vascular grafts containing endothelium and smooth-muscle using triple-coaxial cell printing