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Comment by DoreenMichele | Hacker News Reader

The brain "takes out the trash" when you sleep.* From what I have read, the accumulation of both amyloid beta and tau are linked to sleep deprivation. They may be markers of sleep deprivation and treating the sleep deprivation may be the best thing to do, though that probably won't get someone famous for some billion dollar drug discovery, so no one will likely pursue it.

(Yes, I am aware that some of the research is possibly fraud, other avenues of investigation have been suppressed, etc. I've read quite a few articles about Alzheimer's, my late father had Alzheimer's and ...etc.)

* https://news.ycombinator.com/item?id=25427090

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I read a few years back about a new discovery of lymphatic system connecting to the brain. Small lymphatic veins help clean out these substances, especially during the night. One doctor cured his wife from MS using vein balloons like they use in heart conditions on these veins. I can't verify if this was real of fraudulent information.

The following titles fit with your remarks:

How a newly discovered body part changes our understanding of the brain (and the immune system) (2016)

https://sitn.hms.harvard.edu/flash/2016/how-a-newly-discover...

Edit: Ah, yes. I thought it sounded familiar: Previously discussed on Hacker News: https://news.ycombinator.com/item?id=25426185

Brain’s lymphatic system, just recently discovered, now linked to aging and Alzheimer’s (2018)

https://www.fiercebiotech.com/research/brain-s-recently-disc...

Edit: Quote from the above linked piece:

“As you age, the fluid movement in your brain slows, sometimes to a pace that’s half of what it was when you were younger...We discovered that the proteins responsible for Alzheimer’s actually do get drained through these lymphatic vessels in the brain along with other cellular debris, so any decrease in flow is going to affect that protein build-up.”

Lymphatic Vessels Discovered in Central Nervous System (2015)

https://www.nih.gov/news-events/nih-research-matters/lymphat...

Brain cleaning system uses lymphatic vessels (2017)

https://www.nih.gov/news-events/nih-research-matters/brain-c...

Disturbed sleep should IMO also be looked at - eg UARS and sleep apnea. You can sleep 8h every night and still feel crappy waking up. Maybe disturbed sleep is even worse than lack of sleep? I can feel better after 6h of good sleep than after 9h of disrupted sleep (eg when I know I‘ve been snoring, eg due to throat infection).

To my mind, they are both a form of sleep deprivation. I would say that sleeping poorly, no matter how long you lay there, still constitutes sleep deprivation.

And as people get older, they tend to both sleep less and also sleep less deeply.

Maybe it’s worse than that. If eg a long term lack of REM sleep lead to Alzheimer‘s (it seems to create dementia patterns at least), and people with disturbed sleep get virtually none of that, then they might be worse off than someone with just 5h of sleep.

Having had some very serious sleep issues in the past due to health issues, I would not disagree that sleep quality matters more than how many hours you sleep per se.

The link isn't "disturbed sleep" necessarily. As we age, sleep naturally degrades, and that degradation is in the slow-wave sleep which drives the clearing of amyloid plaques, and tau (along with hormonal response, memory consolidation, nervous system, and more).

The technology we're developing at https://soundmind.co is supporting an Alzheimer's prevention trial beginning in January '23 which is looking at the impact of slow-wave enhancement in the clearing of Amyloid plaques.

By your argument, everybody would get Alzheimer‘s sooner or later. But most old people (still) don’t.

Not necessarily. Though Alzheimer's is an age related disease, and each 5 years increases the likelihood of developing Alzheimer's [1].

The older you get, the more likely you are to get Alzheimer's. Young people don't get Alzheimer's (with the exception of early onset, which is still in an older population).

So if we extend life long enough, will everyone get it?

Unlikely. Just like not everyone with high cholesterol develop heart disease. However the older we get, the worse sleep gets, the more build up of amyloids, the more likely a person is to develop Alzheimer's.

Part of the reason the amyloid theory is in question is because there are people with significant build up of amyloid who do not develop Alzheimer's and there are people with little amyloid build up who do generate Alzheimer's.

[1] https://www.nia.nih.gov/health/what-causes-alzheimers-diseas....

Ok, I still don’t understand why you think disturbed sleep is not a factor to be looked at.

I'm not saying "disturbed sleep", which I believe you are defining as apnea or other respiratory issue, should not be looked at. But even if it is, that does not answer the age related decline in SWS.

Even if there is no other health issue, SWS declines with age. The decline of SWS is linked to increased amyloids, which is linked to Alzheimer's.

Yes, apnea also has an impact on SWS, with the same relationship to amyloids and Alzheimer's, but solving the apnea does not solve the age related decline.

What if the underlying mechanism causing Alzheimer's is responsible for the deterioration in sleep quality in the first place? If you put it simply like "bad sleep causes Alzheimer's" you make almost exactly the same mistake as the researchers who came up with Beta-Amyloid thesis: there are plaques, they must be responsible for destroying the cells. But as time has shown, the real causality is much more complex.

I agree that all directions should be explored. I wonder if there's already a database of Alzheimer patients that includes sleep quality measurements?

I agree that fixing sleep quality is not simple and that getting to the root causes of lack of sleep quality for a specific individual is the optimal means to pursue this. (I am certainly not interested in, say, promoting sleeping pills as an answer.)

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