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‘A Rinsing of the Brain.’ New Research Shows How Sleep Could Ward Off Alzheimer's Disease

Thursday, August 6, 2020

Each of us carts around a 3-lb. universe that orchestrates everything we do: directing our conscious actions of moving, thinking and sensing, while also managing body functions we take for granted, like breathing, keeping our hearts beating and digesting our food. It makes sense that such a bustling world of activity would need rest. Which is what, for decades, doctors thought sleep was all about. Slumber was when all the intricate connections and signals involved in the business of shuttling critical brain chemicals around went off duty, taking time to recharge. We're all familiar with this restorative role of sleep for the brain--pulling an all-nighter or staying awake during a red-eye flight can not only change our mood, but also affect our ability to think clearly until, at some point, it practically shuts down on its own. When we don't get enough sleep, we're simply not ourselves.

Yet exactly what goes on in the sleeping brain has been a biological black box. Do neurons stop functioning altogether, putting up the cellular equivalent of a Do Not Disturb sign? And what if a sleeping brain is not just taking some well-deserved time off but also using the downtime to make sense of the world, by storing away memories and captured emotions? And how, precisely, is it doing that?

A year later, a biological explanation for why poor sleep might be linked to Alzheimer's emerged. Dr. Maiken Nedergaard, co-director of the Center for Translational Neuromedicine at the University of Rochester, identified a previously ignored army of cells that is called to duty during sleep in the brains of mice and acts as a massive pump for sloshing fluid into and out of the brain. This plumbing system, which she dubbed the "glymphatic system" (it works in parallel to the lymph system that drains fluid from other tissues in the body), seemed to perform a neural rinsing of the brain, swishing out the toxic proteins generated by active neurons (including those amyloid fragments) and clearing the way for another busy daily cycle of connecting and networking.

Taken together with Holtzman's discovery that levels of amyloid spiked during the day and dropped during sleep, Nedergaard's findings gave further credence to the theory that sleep might perform a housekeeping function critical for warding off diseases like Alzheimer's. "These results very much support the notion that one of the roles of sleep is to actually accelerate the clearance of beta amyloid from the brain," says Nora Volkow, director of the U.S. National Institute on Drug Abuse.

Animal Study Shows Human Brain Cells Repair Damage in Multiple Sclerosis

Tuesday, May 19, 2020

A new study shows that when specific human brain cells are transplanted into animal models of multiple sclerosis and other white matter diseases, the cells repair damage and restore function.  The study provides one of the final pieces of scientific evidence necessary to advance this treatment strategy to clinical trials.

“These findings demonstrate that through the transplantation of human glial cells, we can effectively achieve remyelination in the adult brain, ” Steve Goldman, M.D., Ph.D., professor of Neurology and Neuroscience at the University of Rochester Medical Center (URMC), co-director of the Center for Translational Neuromedicine, and lead author of the study.  “These findings have significant therapeutics implications and represent a proof-of-concept for future clinical trials for multiple sclerosis and potential other neurodegenerative diseases.”

The findings, which appear in the journal Cell Reports, are the culmination of more than 15 years of research at URMC understanding support cells found in the brain called glia, how the cells develop and function, and their role in neurological disorders. 

Goldman’s lab has developed techniques to manipulate the chemical signaling of embryonic and induced pluripotent stem cells to create glia.  A subtype of these, called glial progenitor cells, gives rise to the brain’s main support cells, astrocytes and oligodendrocytes, which play important roles in the health and signaling function of nerve cells. 

Maiken Nedergaard honored by American Stroke Association for dedication to stroke research

Monday, February 24, 2020

Maiken Nedergaard, M.D., D.M.Sc., co-director of the Center for Translational Neuromedicine, professor in the Departments of Neurology, Neuroscience and Neurosurgery, received the Thomas Willis Lecture Award from the American Stroke Association. The award honors Nedergaard’s career of significant contributions to the basic science of stroke research.

The Nedergaard lab is dedicated to deciphering the role of neuroglia, cell types that constitute half of the entire cell population of the brain and spinal cord.

Last month, the lab published research showing that during a stroke the glymphatic system goes awry, triggers edema and drowns brain cells. In 2012, Nedergaard and her colleagues first described the glymphatic system, a network that piggybacks on the brain’s blood circulation system and is comprised of layers of plumbing, with the inner blood vessel encased by a ‘tube’ that transports cerebrospinal fluid (CSF). The system pumps CSF through brain tissue, primarily while we sleep, washing away toxic proteins and other waste.

The Thomas Willis Award honors the prominent British physician credited with providing the first detailed description of the brain stem, the cerebellum and the ventricles, with extensive hypothesis about the functions of these brain parts. The award recognizes contributions to the investigation and management of stroke basic science.

Nedergaard was one of eleven leading scientists honored for their work by the American Stroke Association. The awards were given during the American Stroke Association’s International Stroke Conference in Los Angeles.