Osteoarthritis – It’s all in the Genes?

What does the activity of 28 genes have to do with osteoarthritis, the most common disorder affecting the knee?

Perhaps a lot.

Robert H. Brophy M.D. and M. Farrooq Rai, Ph.D., researchers at Washington University, St. Louis, Missouri, found four aging-related genes and one obesity-related gene behaving abnormally in torn meniscus tissue.

As Jim Dryden reported in Newsroom, heavy patients had low activity levels in the obesity gene, and older patients had low activity in aging-related genes. The researchers speculated that low activity in the genes may contribute to disease by leaving the tissue without enough of the proteins necessary for the meniscus to function normally.

A co-investigator of the study that involved 68 people, who had surgery to repair or remove a torn meniscus, is Linda J. Sandell, PhD., president of the Osteoarthritis Research Society, Mildred B. Simon Research Professor of Orthopaedic Surgery and leader of the Center for Musculoskeletal Research. She said, “The meniscus is a stable, slowly changing tissue. But if it’s overstimulated, that usually means it’s being irritated in some way. What we don’t know at this point is whether the meniscus is irritated because it was torn by injury or whether it’s responding to something else. It’s even possible that the tissue tore because it already was in a pre-osteoarthritis condition.”

The researchers hope to find markers for osteoarthritis long before patients actually develop symptoms. While the current study looked primarily at the activity of genes already suspected of being involved in the development of osteoarthritis they plan to analyze every gene that is active in meniscus tissue. “We’re beginning to learn that the meniscus itself is manufacturing things that could degrade tissue in the knee, so it may be an active player in osteoarthritis, “said Sandell.