Researchers have found that the risk for obesity and Type 2 diabetes is elevated in those who suffer from chronic sleep loss or who carry out shift work.
Epidemiological studies carried out by researchers at Uppsala University, Sweden, have discovered that one night of sleep loss has a tissue-specific impact on the regulation of gene expression and metabolism in humans.
Previous studies have highlighted how metabolic functions can be affected by disruptive sleep; however, until now it has remained unknown whether sleep loss per se can cause molecular changes at the tissue level.
Conducting multiple molecular analysis
The study focused upon biopsies (small tissue samples), whereby samples of subcutaneous fat and skeletal muscle was taken from participants. These two tissues often exhibit disrupted metabolism in conditions such as obesity and diabetes.
Findings revealed that the sleep loss condition resulted in a tissue-specific change in DNA methylation, one form of mechanism that regulates gene expression.
DNA methylation is a so-called ‘epigenetic modification’ that is involved in regulating how the genes of each cell in the body are turned on or off, and is impacted by both hereditary as well as environmental factors, such as physical exercise.
“Our new findings indicate that sleep loss causes tissue-specific changes to the degree of DNA methylation in genes spread throughout the human genome,” says Jonathan Cedernaes, lead researcher from Uppsala University.
“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.”
Metabolic ‘memory’ can be formed
Cedernaes continues to explain: “Epigenetic modifications are thought to be able to confer a sort of metabolic ‘memory’ that can regulate how metabolic programmes operate over longer time periods.
“We therefore think that the changes we have observed in our new study can constitute another piece of the puzzle of how chronic disruption of sleep and circadian rhythms may impact the risk of developing for example obesity.”
What does the future hold?
Due to the limitations of conducting the research over a short period of time, the researchers therefore do not know how other forms of sleep disruption of circadian misalignment would have affected the participants’ tissue metabolism.
Cedernaes concludes: “It will be interesting to investigate to what extent one or more nights of recovery sleep can normalise the metabolic changes that we observe at the tissue level as a result of sleep loss.”