If bone growth is encouraged at some other part of the body, it is possible to use the new growth for grafting the damaged bone.
Researchers for the study, who will publish their report online next week in the Proceedings of the National Academy of Sciences, had made a departure from the usual practice of tissue processing to develop a new way for bone repairing.
The current approach currently used by orthopedic surgeons to repair serious bone breaks is to remove small pieces of bone from a patient?s rib or hip and fuse them to the broken bone. They use the same method to fuse spinal vertebrae to treat serious spinal injuries and back pain. Although this works well at the repair site, the removal operation is extremely painful and can produce serious complications. If the new method is confirmed in clinical studies, it will become possible to grow new bone for all types of repairs instead of removing it from existing bones. For people with serious bone disease, it may even be possible to grown replacement bone at an early stage and freeze it so it can be used when it is needed, said V. Prasad Shastri, the lead author of the study.
Despite the fact that living bone is continually growing and reshaping, the numerous attempts to coax bone to grow outside of the body ? in vitro ? have all failed. Recent attempts to stimulate bone growth within the body ? in vivo ? have had limited success but have proven to be extremely complex, expensive and unreliable.
Shastri and his colleagues took a new approach that has proven to be surprisingly simple. They decided to take advantage of the body?s natural wound-healing response and create a special zone on the surface of a healthy bone in hopes that the body would respond by filling the space with new bone. The approach lived up to their highest expectations.
A thin outer layer called the periosteum covers long bones in the body. The layer is a little like scotch tape: The outside is tough and fibrous but the inside is covered with a layer of special pluripotent cells which, like marrow cells, are capable of transforming into the different types of skeletal tissue. So Shastri and his collaborators decided to create the bioreactor space just under this outer layer.
They created the space by making a tiny hole in the periosteum and injecting saline water underneath. This loosened the layer from the underlying bone and inflated it slightly. When they had created a cavity the size and shape that they wanted, next the researchers removed the water and replaced it with a gel that is commercially available and approved by the FDA for delivery of cells within the human body. They chose the material because it contained calcium, a known trigger for bone growth. Their major concern was that the bioreactor would fill with scar tissue instead of bone, but that didn?t happen. Instead, it filled with bone that is indistinguishable from the original bone.
The scientists intend to proceed with the large animal studies and clinical trials necessary to determine if the procedure will work in humans and, if it does, to get it approved for human treatment. At the same time, they hope to test the approach with the liver and pancreas, which have outer layers similar to the periosteum.
Medindia on bone disease: Further information
Bone disease: Bone disease may be of various types, inherited or acquired. Some common bone diseases are osteoporosis, Paget?s bone disease, and myeloma bone disease.
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