ARLINGTON, Va., Oct. 16, 2002—A faint pulse of liquid may provide enough mechanical stimulation to grow solid bone outside the body, researchers report.

A major challenge to growing bone for transplant is mimicking conditions inside the body, such as the natural stresses and strains that challenge bone to grow strong.

In the Oct. 1 issue of Proceedings of the National Academy of Sciences a group led by Whitaker investigator Antonios Mikos, Ph.D., of Rice University reported that even a modest flow rate has far-reaching effects on the development of a solid, three-dimensional bone structure.

"Researchers have used fluid flow to stimulate bone growth before, but no one has looked at its effects on three-dimensional cultures that have been subjected to continuous stimulation for several days," Mikos said.

His group put immature bone cells (osteoblasts) from rats into small Plexiglas chambers filled with a scaffold of titanium mesh. After the cells attached to the mesh, a liquid rich in growth factors and other nutrients was pumped through the chambers for 16 days. For comparison, the researchers left a second group of cells in a stagnant pool of nutrients.

"We found that even the lowest flow rate produced a significant increase in the formation of mineralized bone," Mikos said. "Moreover, the mineralized bone that formed in samples subjected to flow was thick and well-developed, similar to what we find in natural bone. The bone matrix formed by the static samples was thin and brittle."

More studies are needed to determine the exact flow rate needed to produce the strongest, healthiest bone possible.

The research was supported by the National Institutes of Health and the National Aeronautics and Space Administration. Mikos's earlier work in cell and tissue engineering was supported by a research grant from The Whitaker Foundation.

Contact:
Antonios Mikos, Rice University
Frank Blanchard, Whitaker Foundation