Synthetic blood vessel grafts are typically made of woven synthetic polymer yarn and used to replace diseased arteries. However, the body’s immune system sometimes recognizes the material as foreign and causes blood clots on the grafts and creates scarring that can clog the tube. The researchers suggest that the engineered human tissue blood vessels don’t require synthetic materials, making them easily accepted by the body’s immune response.
“Blood vessels are just one example of what can be done with our new textile approach to tissue engineering,” lead author on the study Nicolas L’Heureux said in a news release. “it can be used to make practically any shape by weaving, braiding or knitting the threads and allows very good control of the mechanical properties of the final product.”
The researchers designed the threads using a biomaterial called the cell-assembled matrix (CAM), which was developed by L’Heureux’s research team. CAM consists of mostly collagen, which is a natural protein in the body that strengthens tissues and organs. The CAM material is accepted by the body because it is made of human material and isn’t chemically modified.
In the study, L’Heureux and the researchers showed that they could make yarn by cutting CAM sheets into ribbons that can be directly used or twisted into threads. The threads can then be woven as blood vessels that display excellent mechanical properties without the need for synthetic scaffolding or chemical treatments.
“It is time-consuming and costly to get CAM layers to stick together,” L’Heureux said. “The new textile assembly approach is not only more versatile but also has the potential to be automated which would make it even faster, easier and cheaper to use.”
The researchers suggest that CAM could be used to jumpstart the regeneration of many tissues and organs as well. So far the team has made lab-grown skin for burn patients and guides that repair nerve injuries using CAM. They plan to build more blood vessel prototypes to learn the best ways to handle CAM threads and ribbons and will begin testing the vascular grafts in animals.
The research was published in the FASEB Journal.