Slicing and dicing: This illustration shows how a section of bone with a tumor (very top) can be removed (A), leaving a gap in the bone. The periosteum is then cut and peeled back (B), but remains intact. The bone underneath is then moved down (C) to fill the gap, and the periosteum is sutured around the area where the bone was removed.
The researchers have also created an artificial periosteum sleeve, which they tested in sheep, for bone injuries where there is not enough tissue available. The artificial membrane was seeded with collagen; a mixture of collagen and periosteal cells taken from a particular sheep; or pieces of periosteum from the patient’s surrounding bone. The researchers wrapped the sleeve around the injured area and sewed it on like a patch. They found that the sheep given the periosteum alone experienced the fastest repair, with new bone growth two to three weeks after surgery.
The work “combines tissue engineering approaches with surgical intervention and leverages the natural ability for repair,” says Elisseeff.
One problem is that stem cells can differentiate into different things like tendons, cartilage, or bone, says Marcus. The researchers showed that the stem cells in the periosteum were coaxed into becoming bone by mechanical stress. For instance, in the sheep experiments, the mechanical cues happen naturally when the sheep shift their weight.
“There are lots of experimental techniques but few clinical methods, and if this has been successful in patients, that is where the real breakthrough will be,” says Farshid Guilak, a professor of orthopedic surgery and director of the Orthopaedic Bioengineering Laboratory at Duke University Medical Center.
“This is very important progress,” adds Yunzhi Yang, an assistant professor at Houston Biomaterials Research Center at the University of Texas Health Science Center in Houston.
Knothe Tate says the plan is to license the technology to companies by the end of the year, and says there are a couple of “major players” interested. “We want to provide a cheap alternative that can be widely used in the field,” she says.