Carnegie Mellon develops new process for growing bone

Researchers use new synthetic hydro-gel

Carnegie Mellon University’s Jeffrey Hollinger and his research team will receive $1.12 million over the next four years from the National Institutes of Health (NIH) to develop a new therapy for regenerating bone.

Bone, often called the structural steel and reinforced concrete of the human body, supports the body the way a steel framework supports a skyscraper, and it protects its vital organs the way a cast-concrete roof protects’ its building occupants. “Unfortunately, bone loss is an unavoidable consequence of aging, osteoporosis and many traumatic accidents,’’ Hollinger said.

To address the challenges of safe and effective therapy to restore form and function to deficient bone architecture, Hollinger’s research team at Carnegie Mellon’s Bone Tissue Engineering Center has developed an innovative therapy for growing bone by inserting a non-viral gene into the body to induce cells to grow bone.

“We are injecting the NTF gene into a site where bone is deficient via a synthetic hydro-gel made from a hyaluronic acid-based polymer,’’ Hollinger said. “The hydro-gel/NTF is non-immunogenic and is designed to restore form and function to bone deficiencies.’’

Some of the first pre-clinical trials will involve growing bone in the jaw, said Hollinger. And according to transportation officials, about 10 percent of vehicle accident injuries involve the jaw and the flat bones in the face. “Restoring periodontal bone loss is a high priority for our team, and Bruce Doll, head of the Department of Periodontology at the University of Pittsburgh is leading this challenge,’’ Hollinger said.

Through ever-improving surgical techniques, the replacement of bone has been done via bone grafting either from the patient’s own body or from animal (usually cow) bone. But because the human body is inclined to reject most ’non-self’ grafts, Hollinger’s synthetic approach to growing bone will eliminate immune rejections. His research team includes Doll at the University of Pittsburgh’s Dental School and Carnegie Mellon Bone Tissue Engineering Center scientists Yunhua Hu and Huihua Fu, the two scientists who perfected the NTF-hydrogel therapy, and whose work was the foundation for the NIH grant. .

In addition to growing bone for injuries to the jaw, Hollinger’s research team plans to use the new bone regeneration process to treat osteoporotic fractures, and in other applications in other pasrts of the body including the spine, pelvis and all powerful thigh bone – about 20 inches long and more than an inch across at the midshaft. A mature body contains more than 600 muscles and 206 bones, not counting the tiny seasmoid bones – like sesame seeds – embedded in the tendons of the thumb, big toe and other pressure points.

“After blood, bone is the most frequently transplanted tissue. Current therapies for bone grafting fall short of the mark. The Bone Tissue Engineering Center is developing exciting new bone theraputics that will offer surgeons and their patients much better options. And the NTF/injectable hydrogel is one such example therapy from the Carnegie Mellon-Pitt team,’’ Hollinger said.