Some experiments have implanted these empty scaffolds on their own and let new bone grow into them. Growing new bone in the scaffold for weeks before implanting it could have advantages, says Gordana Vunjak-Novakovic, a biomedical engineer at Columbia University and senior author on the new paper. In the new study, Vunjak-Novakovic and her colleagues tested that idea in 14 pigs with facial bone damage. These were carved with a tiny computer-guided pin that shaved away material to match 3D images of each pig’s jaw, created from a computed tomography scan. Next, the researchers sucked some fat from the pigs’ backs and isolated precursor cells that can become bone, known as mesenchymal stem cells. Over 6 months, pigs in all three groups regrew a portion of the missing jaw, but regrowth was more complete in the seeded grafts, the researchers report online today in Science Translational Medicine . In tests of mechanical strength, only these grafts could withstand the same stress as the original bone, and only they reached and maintained the height of the original bone. Clinical trials in humans, however, are at least three years away.
– For the first time, scientists have successfully implanted living bone grown in a laboratory, Live Science reports. And while those implants were in miniature pigs, not humans, it's pretty impressive nonetheless. Scientists removed part of the jaw bones of 14 pigs, carved cow thighbones into the right shape, removed all the cells from the cow bones, saturated the cow bones with stem cells from the pigs, and left the bones to grow in the lab. When the new, living bones were implanted in the pigs, they showed impressive regrowth and returned the jaw to full strength, according to Science Magazine. “The pigs woke up, and a half-hour later they were eating,” researcher Gordana Vunjak-Novakovic tells the New York Times. “We thought they would be in pain. But no, they’re doing great.” The researchers published their findings this month in Science Translational Medicine. They want to try the process in humans in the next few years. At the moment, no great options exist for people who need replacement bones due to injuries, birth defects, or diseases. There are titanium replacements or donated bones, but those come with the risk of rejection. Doctors replacing facial bones currently take the bone from elsewhere in the patient's body, but that causes a new injury, and it can be hard to find a large enough chunk of bone to borrow. Prior methods of bone regrowth have involved letting the new bone grow inside the body, but researchers say growing it first in a lab could have a number of benefits. (Scientists hope to grow human organs in farm animals.)