The circadian rhythm, also known as the circadian clock, is the body’s ability to predict changes in geophysical time and pair its own behaviors with the patterns it observes. Most of us know it as the system by which we determine when to sleep and wake, but it actually controls lots of our other bodily functions and hormone levels. Its function is also affected by more than just the cycle of light and darkness on our planet. In fact, scientists have recently discovered that health conditions such as diabetes may impair it, causing a disruption of hormones and other healthy functions of the body.
Researchers at the University of Geneva (UNIGE) and at the University Hospitals of Geneva (HUG), Switzerland, compared the pancreatic cells of donors with type 2 diabetes to the pancreatic cells of healthy people. They discovered that the circadian oscillators of the cells from people with type 2 diabetes were compromised, so their circadian rhythms were disturbed and their hormone secretions disrupted.
“The verdict is indisputable,” says Dr. Charna Dibner. “The biological rhythms of the islet cells in type-2 diabetes exhibit both reduced amplitudes of circadian oscillations and poor synchronization capacity. As a result, hormone secretion is no longer coordinated. Moreover, the defects in temporal coordination of insulin and glucagon secretion observed in patients with type-2 diabetes were comparable to those measured in healthy islet cells with artificially-disrupted circadian clock.”
A previous study has shown that disrupted circadian clocks in rodents led to impaired insulin and glucagon production, contributing to the development of diabetes. Researchers later learned that the same was true for humans.
“We had also previously observed that if the clocks of human pancreatic cells were artificially disrupted in the cellular culture in vitro, secretion of the key islet hormones — insulin and glucagon — was compromised,” says Volodymyr Petrenko, a researcher in Dr. Dibner’s lab and the first author of these publications. “Hence our next step, that we report here, was to unravel whether the circadian rhythms were perturbed in human pancreatic islets in type 2 diabetes, and, if so, how would this perturbation affect the islet function.”
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Happily, researchers also learned that there may be a cure for this condition. Using a “clock modulator molecule” called Nobiletin, which was extracted from the peel of a lemon, they were able to repair the affected cellular clocks and partially restore islet cell function. While this doesn’t mean we’ve discovered the cure for diabetes, we do better understand the mechanism which causes it to occur and how we might go about managing the issue in the future.
“As soon as we got the clocks back in sync, we also observed an improvement in insulin secretion,” says Petrenko. He and the rest of the team hope to be able to use this new information to come up with an innovative solution to diabetes and the disruption of circadian clocks in the future.
Luckily, the cells in our pancreases respond to more stimuli than just the information coming from our circadian clocks. There are other things people with diabetes can do to help their islet cell function improve so that they can manage their condition more easily.
“Pancreatic cells are also subject to the rhythm of fasting and food intake, and to a tight hormonal regulation,” says Dr. Dibner. “Coordinating all levels of regulation, therefore, allows the optimization of metabolic functions. Indeed, if you eat the same food but at night rather than during the day, you may gain weight much faster, due to a suboptimal response of your metabolism.”
Working to improve your circadian clock function through eating earlier in the day and not staying up well into the night could really do a lot to help you manage your diabetes and even reach the point of remission. We can’t wait to see the results of later studies on this topic!Whizzco