Chronic Sleep Loss May Lead to Loss of Brain Cells

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In today’s hectic, fast-paced world, all too often we hear people say they haven’t gotten enough rest and plan to “catch up” on sleep over the weekend. However, new research suggests chronic sleep loss may be more serious than previously thought and may even lead to loss of brain cells [1].

Using a mouse model of chronic sleep deprivation, researchers at the Center for Sleep and Circadian Neurobiology at the Perelman School of Medicine and collaborators from Peking University, have determined that staying awake too long is linked to injury and loss of neurons called locus ceruleus (LC) neurons, which are essential for alertness and optimal cognition.

The mice were examined following periods of normal rest, short wakefulness, or extended wakefulness, modeling a shift worker’s typical sleep pattern. Scientists found that LC neurons upregulate a protein called sirtuin type 3 (SirT3) in response to short-term sleep loss. SirT3 is important for mitochondrial energy production and redox (reduction-oxidation) responses, and protects the neurons from metabolic injury. With extended wakefulness, the SirT3 response is absent. After several days of shift worker sleep patterns, LC neurons in the mice showed reduced levels of SirT3 and increased cell death.

Lead author Sigrid Veasey, MD, associate professor of Medicine at the University of Pennsylvania’s Perelman School of Medicine stresses that more work needs to be done to determine whether this phenomenon occurs in humans and, if so, how much wakefulness puts people at risk of neural injury [2]:

In light of the role for SirT3 in the adaptive response to sleep loss, the extent of neuronal injury may vary across individuals. Specifically, aging, diabetes, high-fat diet and sedentary lifestyle may all reduce SirT3. If cells in individuals, including neurons, have reduced SirT3 prior to sleep loss, these individuals may be set up for greater risk of injury to their nerve cells.

The study appears in the Journal of Neuroscience [1].

References

1. Zhang et al. Extended wakefulness: compromised metabolics in and degeneration of locus ceruleus neurons. J Neurosci. 2014 Mar 19;34(12):4418-31. doi: 10.1523/JNEUROSCI.5025-12.2014.
   View abstract
2. Penn Medicine Researchers Show How Lost Sleep Leads to Lost Neurons. Penn Medicine Press Release. 2014 Mar 18.