Researchers at the Johns Hopkins School of Medicine say that they have identified the cellular protein that drives both bone and fat formation in certain stem cells. Moreover, these cells can be manipulated in favor of bone building, at least in clinical trials in rats and human cells. If this power can be harnessed in humans, we may be able to make fractures heal faster, prevent bone loss due to aging and even speed up recovery time following surgery.
A report on the findings was published online in the journal Scientific Reports, where researchers spoke about the cellular insights.
“Our bones have a limited pool of stem cells to draw from to create new bone,” said Aaron James, associate professor of pathology at the School of Medicine and the study’s senior author. “If we could coax these cells toward a bone cell fate and away from fat, it would be a great advancement in our ability to promote bone health and healing.”
Regenerative Bone Cells
Previous studies on this type of stem cell has found that these cells can become either bone or fat, but this study focuses more on understanding what signaling proteins determine whether bone or fat is produced. For their study, researchers genetically engineered stem cells to block the production of the WISP-1 protein. In cells without WISP-1, they found that four genes that cause fat formation were turned on 50 to 200 percent higher than control cells that contained the WISP-1 protein.
Next, researchers engineered stem cells to produce more WISP-1 proteins than normal, and they found that three genes controlling bone formation became twice as active than the control cells, while fat-driving genes decreased in activity by 42 percent. With this information, the team then wanted to see if the protein could be harnessed to improve bone healing after spinal fusion procedures. Nearly 400,000 spinal fusions are performed in the US each year alone, and the procedure involves connecting two vertebrae with a metal rod so they grow into a single bone.
“Such a procedure requires a massive amount of new bone cells,” said James. “If we could direct bone cell creation at the site of the fusion, we could help patients recover more quickly and reduce the risk of complications.”
Researchers mimicked the spinal fusion procedure in rats and injected the human stem cells with added WISP-1, and after four weeks they observed more bone healing than the control group.
“We hope our findings will advance the development of cellular therapies to promote bone formation after surgeries like this one and for other skeletal injuries and diseases, such as broken bones and osteoporosis,” said James.
