The same stem cells that heal broken bones can also generate arthritic bone spurs called osteophytes, according to USC researchers. Their study is published in the Annals of the Rheumatic Diseases.

“Although these stem and progenitor cells promote healthy bone repair in other contexts, they are inappropriately activated to cause a pathological bony protuberance in the context of arthritis.”

— Gage Crump, a professor of stem cell biology and regenerative medicine at USC, and the paper’s co-corresponding author

Led by Crump and Cosimo de Bari from the University of Aberdeen in the UK, an international team of scientists made this discovery by studying mice that had sustained a type of knee injury that causes arthritis, a media release from Keck School of Medicine of USC explains.

In these mice, a different-colored fluorescent protein labeled each of eight distinct cell populations. This allowed the scientists to view the fluorescent labels under a microscope and trace how the various cell populations contribute to the formation of arthritic bone spurs.

The major culprit turned out to be a type of stem cell with activity in a gene called Sox9, which is also involved in bone repair. At the edge of the arthritic joint, these cells contributed to cartilage outgrowths that later turned into pathological bone spurs. These cartilage outgrowths had many of the distinctive hallmarks of the cartilage seen during bone regeneration, suggesting further parallels between pathological bone spur formation and normal bone repair, per the release.

“By resolving the cellular origins of osteophytes, our work provides clues for how to target these painful bone spurs that develop at the edge of joints in many arthritis patients.”

— Gage Crump

[Source(s): Keck School of Medicine of USC, EurekAlert]

Related Content:
Harness Newly Discovered Tendon Stem Cells to Treat Injuries
Neural Stem Cells ID’d as Potential Post-Stroke Motor Recovery Aid
Bone Marrow Stem Cells Demonstrate Promise as Knee OA Therapy