The research team injected MOTS-c into mice of different ages: young (2 months), middle-aged (12 months) and old (22 months). Then they put the mice through their paces. When the mice were presented with physical challenges — including maintaining balance on a rotating rod and running on an accelerating treadmill — mice that received the MOTS-c treatment fared significantly better than untreated mice of the same age. This happened in every age group.
Even mice that had been fed a high-fat diet showed marked physical improvement after the treatment and less weight gain than untreated mice.
The scientists also found that the oldest mice, those nearing the end of their lives, showed improvement after being treated with MOTS-c. “This late-life treatment improved grip strength, gait (measured by stride length) and physical performance, which was assessed with a walking test (running was not possible at this age),” they wrote.
“The older mice were the human equivalent of 65 and above and once treated, they doubled their running capacity on the treadmill,” Lee said. “They were even able to outrun their middle-aged, untreated cohorts.”
The results from the study are extremely promising for future translation into humans, Lee said, especially considering the results were obtained even with treatment starting at older ages.
“Indicators of physical decline in humans, such as reduced stride length or walking capacity, are strongly linked to mortality and morbidity,” he said. “Interventions targeting age-related decline and frailty that are applied later in life would be more translationally feasible compared to lifelong treatments.”