Researchers discover cartilage contributes to rheumatoid arthritis

September 18, 2014

Topic: physical therapy

Researchers from Melbourne found that despite previous notions, cartilage actually actively helps destroy and reshape bones and joints in people with rheumatoid arthritis.

Researchers from Melbourne found that, despite previous beliefs, cartilage actually actively helps destroy and reshape bones and joints in people with rheumatoid arthritis. The findings were published in the journal Arthritis and Rheumatology.

The American College of Rheumatology stated that approximately 1.3 million U.S. adults have rheumatoid arthritis. The condition is considered an autoimmune disease, meaning the body attacks itself. Rheumatoid arthritis can destroy the cartilage that surrounds the joints and helps lubricate and cushion them during movement. This destruction can lead to bone disfigurement, poor range of function for joints, and cause joint stiffness and pain. It can affect any joint in the body, most commonly the hands and feet. Certain medications, such as anti-inflammatories, can help treat the condition. Regular physical therapy can also help reduce stiffness and increase mobility.

Though researchers believed that cartilage was an "innocent bystander" in the condition, their findings proved just the opposite.

"Autoimmune diseases such as rheumatoid arthritis are the result of the immune system wrongly attacking normal, healthy tissue," lead researcher Tommy Liu said in a statement. "Our study has shown for the first time that cartilage participates in the production of inflammation-signalling chemicals and contributes to its own destruction."

The study authors examined certain molecules that are responsible for controlling messages in cells that regulate the inflammation in joints. The researchers created a model without SOCS3, a type of protein in the joints, and discovered that tissue was destroyed at a faster rate.

"Without SOCS3, cartilage cells produced enzymes that drove tissue degradation and increased inflammation by releasing signaling molecules that triggered an increased autoimmune response," Liu said. "We also found that cartilage could produce a protein called RANKL that triggers bone remodelling."

Though there is no permanent treatment for rheumatoid arthritis, the researchers believe their findings will help contribute to more efficient temporary treatments. 

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