Cartilage Gives Early Warning of Arthritis, Study Finds

Damage to the tissue that cushions joints occurs even before people feel pain, research shows

By Robert Preidt

HealthDay Reporter

TUESDAY, April 2 (HealthDay News) -- Exercise-related damage in cartilage can help identify people with the earliest stages of osteoarthritis, a new study reveals.

The findings could improve early detection of the painful joint disease and could also be used to improve methods of repairing damaged cartilage, said study senior author Alan Grodzinsky, of the Massachusetts Institute of Technology, and colleagues.

For the study, the researchers developed a method that identifies osteoarthritis-related changes that occur in cartilage in response to high-load activities such as running and jumping.

Cartilage is firm, rubbery tissue that cushions bones and keeps them from rubbing together. When osteoarthritis begins to develop, the ability of cartilage to resist physical-activity-related impact is reduced. This is now known to be due to the loss of molecules called glycosaminoglycans (GAGs).

Using their new system, the researchers found that GAG-depleted cartilage loses its ability to stiffen under the forces of high-load activities. GAG loss also caused an increase in the depletion of fluids from the cartilage, which likely reduces protection against the impact of high-load activities.

The findings show how GAG loss at the earliest disease stages reduces the ability of this tissue to withstand high-load activities, according to the study, which was published in the April 2 issue of the Biophysical Journal.

"This finding suggests that people with early degradation of cartilage, even before such changes would be felt as pain, should be careful of dynamic activities such as running or jumping," Grodzinsky said in a journal news release.

Osteoarthritis affects about one-third of older adults and is the most common type of joint disorder.

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