By Nathan Seppa
A small molecule dubbed kartogenin encourages stem cells to take on the characteristics of cells that make cartilage, a new study shows. And treatment with kartogenin allowed many mice with arthritis-like cartilage damage in a knee to regain the ability to use the joint without pain.
The findings provide new clues in the long-running effort to find ways to regenerate cartilage, a central puzzle in the battle against osteoarthritis, scientists report online April 5 in Science.
The new approach taps into mesenchymal stem cells, which naturally reside in cartilage and give rise to cells that make connective tissue. These include chondrocytes, the only cells in the body that manufacture cartilage. Kartogenin steers the stem cells to wake up and take on cartilage-making duties. This is an essential step in the cartilage repair that falls behind in people with osteoarthritis, the most common kind of arthritis, which develops from injury or long-term joint use.
“In the blue-sky scenario, this would be a locally delivered therapy that would target stem cells already there,” says study coauthor Kristen Johnson, a molecular biologist at the Genomics Institute of the Novartis Research Foundation in San Diego.