A recent study suggests that the cycle of fragmentation and repair of mitochondria could be a key factor in maintaining muscle functions during aging.
This cycle of repairing dysfunctional mitochondria and restoring connectivity among energy-producing organelles has been linked to the development and progression of chronic, age-related diseases.
The microscopic worm species C. elegans, which is widely employed in research on metabolism and aging, was the object of a study by researchers at the Joslin Diabetes Center into the impact of mitochondrial dynamics during exercise.
Age-Related Decline in Physical Fitness
Over the course of the animals' 15 days of adulthood, the study saw the usual drop in physical fitness that comes with aging. The aging animals' mitochondria were found to be increasingly fragmented and/or disordered, according to the researchers.
In older worms, the animals’ performance did not return to baseline within 24 hours, and the older animals’ mitochondria underwent a cycle of fragmentation and repair, but the network reorganization was reduced compared to that of the younger animals.
AMPK to Improve Muscle Functions During Aging
The ability of well-known techniques to extend lifespan to enhance exercise capacity as people age was put to the test by the researchers. Worms with higher levels of AMP-activated protein kinase (AMPK), which controls energy during exercise and encourages remodeling of mitochondrial architecture and metabolism, had better physical fitness.
They also showed that exercise performance may be maintained during aging but not improved. Worms that had been genetically modified to lack AMPK showed decreased physical fitness as they aged as well as impairments to the recovery cycle.
These findings provide insight into the mechanisms underlying exercise responsiveness and potential entry points for interventions to maintain muscle functions during aging.
The study demonstrates the importance of mitochondrial dynamics in maintaining physical fitness and shows that this cycle of fragmentation and repair could be crucial to forestalling the decline in muscle functions during aging.
Determining how mitochondrial network flexibility affects physical fitness, longevity, and aging-related disorders in humans will be very interesting.
Reference: “Exercise preserves physical fitness during aging through AMPK and mitochondrial dynamics” by Juliane Cruz Campos, et al, 3 January 2023, Proceedings of the National Academy of Sciences.
https://doi.org/10.1073/pnas.2204750120