Date Published: 26 July 2005
Development of method for growing bone for grafts within patient's own body
An international team of biomedical engineers based at both Imperial College (London) and Vanderbilt University (Nashville, TN) has demonstrated for the first time that it is possible to grow healthy new bone reliably in one part of the body and use it to repair damaged bone at a different location.
The research is described in a paper titled 'In Vivo Engineering of Organs: The Bone Bioreactor' published online by the Proceedings of the National Academy of Sciences.
V. Prasad Shastri, assistant professor of biomedical engineering at Vanderbilt University led the research and stated that
" We have shown that we can grow predictable volumes of bone on demand ...
_And we did so by persuading the body to do what it already knows how to do."
Co-author Robert S. Langer, Institute Professor at the Massachusetts Institute of Technology and a pioneer in the field of tissue engineering added that:
" This research has important implications not only for engineering bone, but for engineering tissues of any kind."
How is serious bone damage treated now ?
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. Scientists suggest that if the new method is confirmed in clinical studies, it may become possible to grow new bone for all types of repairs instead of removing it from existing bones.
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.
Long bones in the body are covered by a thin outer layer called the periosteum. 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.
Researchers involved in this study 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, 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 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 indistinguishable from the original bone.
Source: Imperial College, London www.imperial.ac.uk
and Vanderbilt University, Nashville TN (USA) www.vanderbilt.edu