Thread by @WesElyMD

1/🧵Wake-Up to how #SLEEP flushes waste from your brain 🧠 @JAMA_current
 
I may get more done when I 💤 less, but I lose the long-game! #Evolution dictated that we gain an advantage by spending 1/3rd of our lives asleep.

I’ll tell you WHY? bit.ly/3qPgzAA

#MedTwitter

2/ Why do we sleep? Brain rest? To process bad decisions or incomplete conversations? Maybe. But the coolest reason is removal of #amyloid & #tau proteins that cause #dementia. Our #glymphatic system does this most efficiently during deep sleep.
 

https://twitter.com/weselymd/status/1390124955996667907?s=21

3/ Have I mentioned that I’m fascinated by the glymphatic system? It’s the lymph system for our #brain & serves as the “garbage” removal program to keep our #neurons healthy. Wanna know more?
 

https://twitter.com/weselymd/status/1390124961583534081?s=21

4/ As an aside, one purpose of sleep is to help prune unused synapses, making the brain stronger & cultivating neurons used more often, like pruning a rose bush improves its health. Now let’s move back to waste management…

5/ Our neurons and glia are busy engines & make waste as a biproduct that is toxic! #AmyloidBeta and #Tau proteins are central to #Alzheimers Dz pathology. For centuries no one thought we had a lymph clearance system in the brain. But we do.

6/ In 2015, lymphatic vessels were shown present by Louveau et al in the meninges of rodents, nonhuman primates & humans.👇

These vessels carry both fluid & immune cells to deep cervical lymph nodes & ultimately to our systemic circulation.
 
go.nature.com/3jYqh2z

7/ Check out Louveau’s conclusion from their 2015 @Nature paper:

“Our discovery of a CNS lymphatic system calls for reassessment of basic assumptions in neuroimmunology & sheds new light on the etiology of neurodegenerative diseases.”

💥 Indeed. Game changing.💥

8/ There are no videos 🎥 of Glymphatics in action because we don’t have good ways to measure flow from vessels & neural tissue into glymphatics. It would take intrathecal gadolinium injections over 24 hrs post contrast. So it’s all still controversial as to how it all works.

9/ Fresh cerebrospinal fluid (CSF) travels into a system sitting next to blood vessels & mixes w waste-rich interstitial fluid (ISF) into regular lymph vessels & then out to the heart. The walls of glymphatic vessels are a super-specialized sieve leading to our “neuropil” 🧐

10/ The ISF itself increases by 60% during sleep (even daytime sleep). But tons of sleep fragmentation can interfere with this and hurt brain healing.

#LongCOVID patients c/o “brain fog” may be particularly hurt here:

https://twitter.com/weselymd/status/1369612807411535872?s=21

11/ In humans, total sleep deprivation for even 1 night causes an increase in the Aβ burden in the hippocampus, which can lead to memory impairment.

🤔 of great minds like #RonaldRegan & #MargaretThatcher who slept little & ended up w brutal #dementia
 
bit.ly/3dLbh3M

12/fin💥 Aβ & Tau deposits in #Alzheimers mirrors MRI glymphatic flow patterns. @CIBScenter we are including #Glymphatics in our BRAIN-2 @NIHRresearch study of 🧠s to understand #dementia following ICU illnesses like #COVID19. Stay tuned & sleep well…
 
bit.ly/3hA9lfV