Sleep Deprivation Induces Metabolic Conditions for Obesity

 It is nearly common knowledge that there is a connection between sleep deprivation and obesity, yet there is much to be explored regarding how exactly sleep deprivation affects bodily functions, metabolism, and body mass. Given the rise in obesity and sleep deprivation among the American population and the fact that both are risk factors for different physical and mental illnesses, it is an area of scientific inquiry in need of research.  It is generally thought that sleep deprivation causes loss of metabolic function, which means more food is stored as fat; thus, obesity occurs.

In Circadian Desynchrony and Health, Dr. Turek and Dr. Summa found numerous negative effects on metabolism due to the inability of healthy sleep function in mice. Using mice as the model organism, they tested mice with a mutation in the Clock core circadian gene, a pivotal gene for sleep function. Interestingly, after ten weeks of diet experimentation, the Clock-mutant mice developed significant increases in body weight compared to the control mice for both a regular and high-fat diet. These Clock-mutant mice became sick with glucose metabolic syndromes as well. The study of islet glucose-stimulated release of insulin demonstrates that the Clock mutant mice had physiological changes impacting weight. The Clock mutant mice had a dysfunctional metabolism as they decreased insulin secretion, which made them prone to issues with glucose homeostasis and an energy imbalance. Given the metabolic dysregulation somehow indirectly or directly caused by the Clock gene mutation, it is unsurprising that the Clock mutant mice were prone to obesity. Through the study of the cellular study of pancreatic tissue and comparison of body mass in mice, this research demonstrates the dangerous effects of somatic inhibition of sleep through the central nervous system’s regulatory function of circadian rhythm.

In Integrated metabolomics and proteomics analysis reveals energy metabolism disorders in the livers of sleep-deprived mice, Dr. Hu and his research team impressively examined the effects of sleep deprivation in mice on body mass, liver health, and other factors. In this lab, the researchers examined the effects of sleep deprivation on mice through behavioral intervention. They behaviorally induced sleep deprivation in mice through an interesting in vivo model of a random motion platform.  The investigation focused on changes to the metabolome, small-molecule chemicals, and the proteome, a full set of proteins, in the functioning of the liver. Like Turek’s lab, one of the focuses was on the change in body weight between the experimental and control mice. This lab recorded the final body weight at the ten-day mark of their sleep deprivation mouse model. Without a significant difference, the sleep deprivation group gained more weight than the control group. Given this experiment lasted a short time in duration, it is unsurprising that the difference in weight change may not yet have been significantly different. After ten days of this in-vivo part of the experiment, the livers were examined, and interesting findings were presented. Three significant pathways were found including the upregulation of the glutamate and downregulation of glutamine in the glutathione metabolic pathway. The role of glutathione metabolism ties in with energy metabolism. Thus, this presents more metabolic evidence of the negative effects of sleep deprivation on mammalian metabolism and energy balance.

          With different modes of research, both studies found that lack of sleep causes metabolic dysregulation which induces obesity in mice. Dr. Turek’s research team focused on somatic inhibition via the Clock mutation, and Dr. Hu’s team utilized behavioral intervention to sleep deprive the mice. In conjunction with each other, these findings suggest that sleep deprivation has a huge impact on the whole-body system at the cellular the outwardly physical level. It raises further questions about how sleep deprivation directly affects organ function, and how the functioning or dysfunction of organs may affect each other.

References:

Vitaterna, M., et al. “Mutagenesis and Mapping of a Mouse Gene, Clock, Essential for Circadian Behavior.” Science, vol. 264, no. 5159, 29 Apr. 1994, pp. 719–725, https://doi.org/10.1126/science.8171325.

Hu, Shuang, et al. “Integrated Metabolomics and Proteomics Analysis Reveals Energy Metabolism Disorders in the Livers of Sleep-Deprived Mice.” Journal of Proteomics, vol. 245, 1 Aug. 2021, pp. 104290–104290, https://doi.org/10.1016/j.jprot.2021.104290. Accessed 17 Feb. 2024.

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