September 4, 2013
Sleep Gives A Boost To Brain-Protecting Cells
Brett Smith for redOrbit.com - Your Universe Online
Scientists have long wondered about the precise biological needs that drive the body’s demand for sleep. While the need for a rest period may seem obvious, researchers are just beginning to uncover the underpinnings of our universal nightly ritual.
According to new research in The Journal of Neuroscience, scientists at the University of Wisconsin, Madison have discovered that sleep allows the body to reinforce the production of myelin, which provides insulation for the brain’s neuronal wiring. Study researchers said their findings could lead to new insights into brain repair and multiple sclerosis (MS), a disease marked by chronic myelin damage.
In the study, the researchers recorded genetic activity in myelin-producing oligodendrocyte cells from mice that either slept normally or were forced to stay awake. While the genes promoting myelin formation were observed to activate during sleep, the genes associated with cell death and cellular stress were switched on when the rodents stayed awake.
In fact, the production rate of immature oligodendrocytes doubled as mice slept, researchers said. The production increase was most significant during REM sleep, which is associated with dreaming.
"For a long time, sleep researchers focused on how the activity of nerve cells differs when animals are awake versus when they are asleep," said study author Dr. Chiara Cirelli, a psychiatrist at the University of Wisconsin, Madison. "Now it is clear that the way other supporting cells in the nervous system operate also changes significantly depending on whether the animal is asleep or awake."
The research team said their findings indicate that sleep loss might worsen some symptoms of MS as the disease causes the body's immune system to attack myelin in the brain and spinal cord. Future studies could examine the connection between sleep and the symptoms of MS, Cirelli suggested.
The Michigan doctor also said her team would like to explore whether a lack of sleep, particularly during adolescence, has long-term consequences for the development and health of the brain.
According to the National Institute of Neurological Disorders and Stroke (NINDS), sleep appears to be essential for our neural circuitry to function properly. Deep sleep has been linked to the release of growth hormones in developing children and young adults. Numerous body cells also demonstrate increased fabrication and fewer breakdowns of proteins during deep sleep. Since these proteins are necessary for cell growth and repairing stress-related or UV damage, deep sleep could easily be defined as "beauty sleep," according to NINDS.
In another MS-related development, the National Institutes of Health (NIH) announced this week that it would be awarding a $1.9 million grant to the Benaroya Research Institute at Virginia Mason (BRI) to locate markers in the human genome which could explain why the immune system is capable of causing damage to the spinal cord and brain.
The broad-based study is expected to look at specific cells within the immune system to see how they can be regulated within models of MS and in humans.
"We want to understand the factors that make these cells target the spinal cord and brain to cause disease," said Estelle Bettelli, co-principal investigator of the study.
“We can also see how these cells behave once the patient receives treatment and if various treatments make the cells act differently," said co-principal investigator Steven Ziegler, director of the BRI Immunology Research Program.