A new study finds that human fat cells follow its own biological clock and operate without the influence of external stimuli like light and food.
Fat cells also serve as energy stores and regulator of appetite through hormone secretion. Even without the effects of light or meal time, these cells can function independently on its own circadian rhythm.
A study published in Scientific Reports reported that fat tissues perform distinct metabolic processes at three specific shifts in a day.
This is the first study of circadian rhythm that involved human fat cells. Seven individuals participated in regulated meal times and sleep-wake cycles.
They were subjected to this routine for 37 consecutive hours without experiencing changes in light, food, and sleep-wake.
“This is the first time that we have been able to identify such rhythms in human fat,” said lead author Dr. Jonathan Johnston from the University of Surrey. “This provides us with more information about how human metabolism changes across the day and possibly why the body processes foods differently during day and night.”
Dr. Johnston and his team found that 727 genes expressed their own circadian rhythm. One-third of these genes peaked in the morning, while two-thirds function in the evening.
Morning-peaking transcripts were vital for gene expression and cell functioning. Those that work during the night are crucial for organic acid metabolism and redox reactions.
Disruption to the circadian rhythm is linked to a variety of negative health effects. Researchers at Uppsala University demonstrated that even one night of sleep loss could have detrimental impact on metabolism. Shift work is linked to chronic sleep loss, obesity, and type 2 diabetes.
Tissue samples from 15 normal-weight individuals were analyzed for changes epigenetic modification. Lab tests showed that one night of sleep loss resulted to significant muscle mass loss and fat accumulation.
“Our parallel analysis of both muscle and adipose tissue further enabled us to reveal that DNA methylation is not regulated similarly in these tissues in response to acute sleep loss,” said lead author Jonathan Cedernaes.
The study was published in the journal Science Advances.