When it comes to arthritic bone spurs, stem cells hurt instead of heal – EurekAlert


IMAGE: Following ligament injury, a bone spur forms at the edge of the damaged mouse knee joint (middle right). This pathological bone spur (pink) is made by the same type of… view more 

Credit: Stephanie Kuwahara/USC Stem Cell

The same stem cells that heal broken bones can also generate arthritic bone spurs called osteophytes, according to a new study 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,” said Gage Crump, a professor of stem cell biology and regenerative medicine at USC. Crump is the paper’s co-corresponding author, along with Cosimo de Bari from the University of Aberdeen in the UK.

Led by Crump and de Bari, an international team of scientists made this discovery by studying mice that had sustained a type of knee injury that causes arthritis. 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