Killing old cells could be the secret to curing jaw pain when chewing, or temporomandibular joint pain.
- Between 45 and 70% of people over the age of 65 show signs of deterioration of the temporomandibular jaw.
- By combining two senolytics, drugs designed to eliminate old cells, it eliminated these senescent cells in the jaw joints of old mice.
- The cartilage was thicker and the bone smoother, promoting better chewing.
Jaw pain when chewing, or temporomandibular joint pain, is both common and difficult to treat. American researchers from the University of Connecticut claim that killing old cells could relieve persistent jaw pain. They presented their results on June 8 in the journal Aging Cell.
Senescent cells accumulate
Temporomandibular jaw (TMJ) problems cause the jaw to click and lock, difficulty chewing, and generally make eating painful. It affects many people intermittently throughout life and tends to worsen with age. Between 45 and 70 percent of people over the age of 65 show signs of TMJ deterioration, according to previous research. Certain interventions, such as massage or functional therapies, may help, but no drugs are currently available to relieve or prevent joint deterioration.
Age worsens the deterioration of joints in many parts of the body, and in many cases this deterioration appears to be related to old, damaged cells that refuse to die. Usually, the cells in our body are constantly renewing themselves. Most of the cells that are damaged or start to turn cancerous are eliminated by our immune system to make way for fresh, young, healthy cells. But sometimes these cells remain. They are called senescent cells. “No one knows why they pile up, but they do”, assures Ming Xu, gerontologist and geneticist, and lead author of the study. Senescent cells don’t just accumulate as they appear to actively promote inflammation and damage to surrounding cells.
That 80 year olds look like 50 year olds
The researchers noticed that by combining two senolytics, drugs designed to eliminate old cells, it eliminated these senescent cells in the jaw joints of old mice. They combined Dasatinib, a senolytic that removes senescent cells from connective tissue like cartilage and bone, and Quercetin, which attacks senescent cells from blood vessels and skin. The combination is necessary because joints are complex structures made up of many different types of tissue.
They tested the combination of these two drugs on 24-month-old mice, which is equivalent to 70-80 year old humans. They gave them the treatments three times every two weeks for six weeks. After this period, the cells in the jaw joints of the aged mice looked more like the cells in the jaw joints of 4-month-old mice, comparable to 15-20 year old humans. The cartilage was thicker and the bone smoother, promoting better chewing.
Clinical trials must continue to be carried out in humans to test this potential treatment. “We’re trying to slow down the whole aging process, make 80 year olds look like 50 year olds.”, concluded Ming Xu.
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