WEDNESDAY, July 28 (HealthDay News) -- For the first time, scientists have been able to grow an entire joint from stem cells, albeit in rabbits not humans. And the joints worked.
"The rabbits were able to hop and walk and bear weight, virtually like normal rabbits," said Dr. Jeremy Mao, senior author of a paper published online July 29 in The Lancet. "This was the first regeneration of the entire joint with restored functioning."
If replicated in humans, the researchers are hoping these regenerated joints would last longer than artificial joints, which have a life span of about 10 to 15 years right now.
This is especially important given the number of younger people (65 and younger) who are now requiring joint replacements, often because of osteoarthritis, the authors stated.
Currently, damaged joints are replaced with joints made of titanium or stainless steel. They have a number of drawbacks, including limited life span.
In the new stem cell-based strategy, the researchers took out the upper forelimb joint (proximal humeral joint) in 10 rabbits.
They then took a two-dimensional laser image of the joint and recreated the joint in three dimensions on a computer. Next, they constructed that 3-D image -- basically an anatomically shaped joint -- using a "bioprinter" that printed with biomaterial rather than ink. Biomaterial contains materials that are compatible with the body and can interact with biological systems.
The 3-D biomaterial "print-out" became the scaffold for the new joint, Mao explained.
The scaffold was placed within the animals. Next, researchers added transforming growth factor beta 3 (TGFB3). "This is a homing molecule which recruits stem cells," Mao explained.
The growth factor did, in fact, entice the rabbit's own stem cells to migrate to the scaffold area and then grow into new cartilage and bone to form a new
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