A drug that has life-extending effects on mice also reverses age-related dental problems in the animals, according to research from the University of Washington School of Dentistry and the Jackson Laboratory in Bar Harbor, Maine.
Periodontal disease is common in older adults, though there are no treatments beyond tooth removal and good oral hygiene, the researchers said. However, they added, treatments targeting the aging process in the mouth might help.
Rapamycin is an immune-suppressing drug currently used to prevent organ rejection in transplant recipients. Previous studies in mice have also suggested that it may have life-extending effects, leading to interest in the drug’s effects in many age-related diseases.
“We hypothesized that biological aging contributes to periodontal disease and that interventions that delay aging should also delay the progress of this disease,” said lead author Jonathan An, DDS, PhD, acting assistant professor at the Department of Oral Health Sciences at the University of Washington.
The researchers added rapamycin to the food of middle-aged mice for eight weeks and compared their oral health with untreated mice of the same age. Like humans, mice also experience bone loss, inflammation, and shifts in oral bacteria as they age.
Using a 3-D imaging technique called microcomputed tomography, the researchers measured the periodontal bone of the rapamycin-treated and untreated mice. The treated mice had more bone than the untreated mice and had actually grown new bone during the period they were receiving rapamycin.
The rapamycin-treated mice also had less gum inflammation. Genetic sequencing of the bacteria in their mouths revealed that these mice had fewer bacteria associated with gum disease and a mix of oral bacteria more similar to that found in healthy young mice as well.
“By targeting this aging process through rapamycin treatment, our work suggests that we can delay the progress of gum disease and actually reverse its clinical features,” said senior author Matt Kaeberlein, PhD, professor of pathology and adjunct professor of oral health sciences at the University of Washington.
But while rapamycin is already used to treat certain conditions, it can make people more susceptible to infections and may increase their risk of developing diabetes, Kaeberlein said, at least at the higher doses typically taken by organ transplant patients.
“Clinical trials in humans are needed to test whether rapamycin’s potential oral health and other benefits outweigh its risks,” he said.
The study, “Rapamycin Rejuvenates Oral Health in Aging Mice,” was published by eLife.
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