A recent study on mice has revealed that circadian rhythms, which regulate daily physiological processes, are not solely governed by a central clock in the brain. Instead, they involve a more intricate system where molecular clocks in both the brain and muscle tissue work together to maintain muscle health and function. The research further indicates that adjusting these clocks through changes in meal timing could potentially preserve muscle function in the elderly.
In the study researchers employed a mouse model called Bmal1 knockout (KO), which inhibits the expression of the Bmal1 clock gene in the suprachiasmatic nucleus. This is the region in the brain responsible for regulating circadian rhythms. In this model, however, they were able to restore Bmal1 expression in various tissues, including skeletal muscle. The KO mice exhibited unusual patterns of activity and inactivity, oxygen consumption, energy expenditure, and glucose and lipid oxidation compared to wild-type mice, demonstrating disrupted circadian rhythms due to the absence of the Bmal1 gene.
By 26 weeks, the knockout (KO) mice had experienced a decrease in both weight and muscle mass compared to their condition at 10 weeks, along with evidence of mitochondrial damage in their muscles. However, when the expression of the gene was reinstated in both the muscle and brain of certain mice, their muscle mass and strength were maintained. This led researchers to conclude that interaction between the clocks in the brain and muscle is essential to stave off early muscle aging.
As individuals grow older, their sleep-wake cycles undergo changes, and they also experience a loss of muscle mass. This study proposes that these phenomena are closely linked. Typically, aging leads to an adjustment in sleep patterns, with older adults tending to wake up earlier in the morning and go to bed earlier in the evening. However, for some elderly individuals, especially those suffering from neurodegenerative diseases like Alzheimer’s, sleep patterns may become highly erratic and fragmented.
This research has discovered a potential method to restore the functioning of circadian clocks in both the brain and muscles. By adopting a time-restricted feeding regimen for older adult mice, the scientists were able to revive rhythmic gene expression in the muscle tissue, effectively preventing the decline in muscle function.
These results shed light on potential physiological shifts that occur with aging and how time-restricted eating could potentially counteract these changes. However, confirmation through human trials is necessary before drawing extensive conclusions about the effects of the circadian clock on human aging. It remains unclear whether such dietary strategies could help prevent muscle aging in people. The observation that limiting food intake to the active phase of mice partially reinstated the function of the central clock and bolstered the skeletal clock underscores the significant role that timing of eating plays in supporting circadian rhythms.
To view the original scientific study click below:
Brain-muscle communication prevents muscle aging by maintaining daily physiology
