UK Scientists: Metabolic Disease Key to OA?

Professor Alan Boyde and colleagues from Queen Mary University of London have identified a new mechanism of joint destruction that is caused by a material that grinds down healthy cartilage and makes painful osteoarthritis (OA) even worse.

Initially, the team looked at the hip of a man with alkaptonuria (AKU). According to the news release, this is a metabolic disease in which a substance called homogentisic acid accumulates in joint cartilage, causing changes to its physical properties. The researchers found high density mineralized protrusions (HDMP), which had previously only been seen in horses. “These protrusions are caused as the body acts to fill in cracks in joint cartilage and can snap off, leading to sharp, dense particles in the joint which grind against healthy tissue. To confirm the findings, the team studied eight hips donated for research by people with osteoarthritis and found the same results as in the alkaptonuria patient.”

Professor Jim Gallagher led the study in Liverpool. In the August 11, 2014 news release he said, “There is no cure for osteoarthritis, but it is one of the leading causes of disability, causing immense pain and difficulty of movement to sufferers. The discovery of HDMP in humans means that for the first time we are seeing an important mechanism in the process which causes the disease. In effect these small, sharp particles could act like an abrasive powder scouring the surfaces of the joint.”

The authors, whose work was published in the Journal of Anatomy, recommend that searching for these HDMPs should now be included in the study of patients with osteoarthritis.