BRISBANE, Australia — Scientists have long believed that our “body clock,” or circadian rhythms, were solely under the control of our brains. However, researchers from the University of Queensland have discovered that the liver plays a significant role in this 24-hour cycle as well.
“Liver disease and metabolic diseases such as diabetes and obesity are associated with disrupted sleep, irregular eating and a disturbance of the circadian clock,” says Associate Professor Frédéric Gachon, in a media release. “This study suggests that the abnormal liver function is likely driving this disturbed rhythm.”
What does a body clock do?
Our circadian clock influences sleep, hormonal secretion, metabolism, and even body temperature. More research continues to surface regarding the consequences of poor circadian health, such as insomnia, depression and other mood disorders, memory and decreased alertness, as well as conditions like heart disease and diabetes.
To better understand these patterns in mammals, Gachon and his team transplanted human liver cells into mice to replace their liver cells. The results showed significant modifications to the circadian rhythm of mice.
“Mice are nocturnal but when their liver cells were replaced with human cells, their circadian clock advanced by two hours – they ate and slept at different times to mice without those transplanted cells,” explains Dr. Gachon.
“The mice in our study started to eat and be active before night-time began, which is very unusual for a nocturnal animal.”
Previously, scientists believed that the suprachiasmatic nucleus, the central hub for circadian timing, was exclusively responsible for controlling these rhythms. This study shows that this isn’t the case.
“This study suggests that the abnormal liver function is likely driving this disturbed rhythm. Our study deepens our understanding of the hormonal and neuronal mechanisms involved in the role of the liver in controlling circadian rhythms. It suggests that restoring liver physiology could benefit the health and wellbeing of patients,” explains Dr. Gachon.
“It also shows that the regulation of circadian rhythms is more complex than we suspected and presents avenues for investigating potential new treatments for metabolic diseases.”
The team hopes that this work can help produce more research that leads to a greater understanding of metabolic diseases as it relates to disrupted body clocks, especially now that it’s clear that the brain isn’t the only part of the body that controls the functions. Further, extensive research may help develop targeted treatments for jet lag, sleep disorders, obesity, mental health disorders, and other health problems associated with this as well.
The findings are published in the journal Science Advances.
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