Changes in Body Clock May Contribute to Osteoarthritis, Researchers Say

Rebecca Lewis June 14, 2013

For the first time, researchers have established that the cartilage cells have a functional body clock that regulates the switching on and off of genes that control tissue function. This explains why people with osteoarthritis experience worse symptoms at certain times of the day. The new study also explains why older people are more prone to this illness.

Researchers at the University of Manchester examined the cartilage tissue in older mice and found that its body clock is 40% weaker than in younger mice. They also looked at the cartilage cells affected by the damage and discovered that the components of the body clock are altered during the early stages of the disease.

All these suggested that the deportation of the body clock contributes to the increased risk of developing osteoarthritis later in life.

The researchers also tested what would happen to the cartilage tissue in mice and cartilage cells in humans if they impose an artificial rhythm mimicking the daily changes to body temperature. They raised the temperature by 2 degrees after every 12 hours for three times and found that the body clock in the cells had been reset and were working in a much better state. The improvement lasted for 7 to 5 days, even after the temperature cycles were removed.

"By imposing a rhythm to boost the internal rhythm in cartilage, our data suggests the aged cartilage clock might be re-tuned.” said Dr Qing-Jun Men, the lead investigator and a Medical Research Council (MRC) Fellow at MU.

In humans, it could be done by using systemic approaches such as scheduled exercise, restricted meal times, or by scheduled warming and cooling of joints. Dr Men believed that imposing a rhythm could have a significant impact on the future management of joint diseases. With further studies, there is a possibility of this method relieving the debilitating symptoms experienced by the sufferers, particularly chronic pain.

Their study also suggests that taking medications based on the cartilage clock could increase the effectiveness of the drug.

Previous research suggests that disruption in body clocks could contribute to a number of health problems, such as obesity, cardiovascular disease, mood disorder and cancer. Dr Men and his colleagues are set to test their theory that body clock disruption may also contribute to osteoarthritis.

The study was published in the journal Arthritis and Rheumatism.

Source of this article:

The circadian clock in chondrocytes regulates genes controlling key aspects of cartilage homeostasis