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Comment by KittenInABox | Hacker News Reader

Why would Ozempic, a chemical affecting a specific receptor found in specific parts of the body, affect alzheimer's? I'm just asking questions here I don't understand what the mechanism of action is that this would be disappointing news.

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Semaglutide (Ozempic) has potential therapeutic effects in neurodegenerative disorders through "modulation of neuroinflammation, enhancement of mitochondrial function, and promotion of neurogenesis". It has shown benefits in animal models of Alzheimer's and Parkinson's. So they're not just testing a random drug, but something that could work.

For details, see: https://pubmed.ncbi.nlm.nih.gov/38921025

This diagram shows how Ozempic can produce these results, the various pathways from the GLP-1 receptor to reduce inflammation, protect neurons, and affect mitochondria: https://cdn.ncbi.nlm.nih.gov/pmc/blobs/87c0/11202139/72234dd...

Thank you, I really appreciate it, as I'm not educated in biochem at all.

"Type 3 diabetes" is one of the speculated causes of alzheimer's. The evidence there is not great.

Fixing type 1 or 2 diabetes does not fix the damage they already did either.

It was correlated to lower Dementia rates in a past study. https://journals.sagepub.com/doi/10.1177/13872877251351329

Thanks, I wasn't aware of this. Do we know how?

I don't think there's a confirmed mechanism (or even whether the fact that it does prevent dementia is a confirmed fact).

But you could speculate that obesity -> cardiovascular issues -> neurological damage, and that could explain things.

We unfortunate know very little about how dementia / Alzheimer's develop in the first place.

Generally this is the answer when there's an announcement like this. Some early paper or analysis showed some (often weak but potentially very interesting) correlation between $new_drug and $scary_disease/$scary_disorder. Doctors and scientists go off and study that in more depth with better controls or more data points and we learn a little more about the world, if you miss the initial paper(s) the follow up can seem a little random.

This new study that did not find a causal link was part of the attempt to find out how. The original study was more of an observation than a deep dive.

You could think of it similar to a study that shows something like "People who don't watch network TV have fewer strokes", which could be an interesting correlation, but the causal effect might be something more like "people who are more health conscious tend to avoid sitting down for extended waking periods" which ultimately has nothing to do with TV.

We don't know the "how" in a surprising number of medicines.

I know we can tell that a chemical does a particular thing in the body, but can we tell that it does not do anything other than that thing? The body is ridiculously complex, and as far as I know we don’t know how every part (or combination of parts) works.

Edit: I mean in the theoretical “this targets the x receptor” kind of way, not in “we tested this and found no causal link” way.

That's why I'm genuinely asking why this would be disappointing, like what was the evidence that this does affect Alzheimer's. You would expect by X does not affect Y by default, so clearly there had to be a theory why you'd spend 2 years on a study to rule it out.

Ozempic is a diabetes drug, and there's a hypothesis that Alzheimer's is really a form of diabetes.

Personally, living with two T1D ( type 1 insulin dependent diabetic, the autoimmune disease not to be confused with the i am old, fat and over eat disorder) when your blood sugar is too high or low , you act weird , you are in a fog . Long term effects of the swings and sustained levels cause brain damage, not necessarily traumatic brain injuries but damage nonetheless.

So i can see the correlation for T1D and undiagnosed T2D cases Alzheimers. Now having a parent with both T2D and Alzheimers when they were taking rebelsis there was a change in their overall mood and activity , but i saw the change was "hey your sugar is under control, and no i am not your buddy from the army" . To be clear the difference is the fog of being unclear about what's going on like you're drunk , vs the grand delusions of seeing a different person that's not there .

This should have been obvious for the researchers.

> This should have been obvious for the researchers.

That's why they do research, to find out instead of just guessing.

T2D is not limited to "old, fat overeaters".

This is anecdotal, I don't have proof but it's something I think is somewhat related. Is that obesity and nuerodegenerative diseases are somewhat related. So that's a guess as to why some people might have though a weight loss drug would potentially be related in some way with alzheimers.

This could just be false though, I can't recall where I heard this information. So do some searching before quoting me.

Obesity often goes hand in hand with poorly regulated blood sugar and high blood pressure, both known risk factors for Alzheimer's.

Significant, sustained weight loss can prevent or reduce the effects of conditions known to increase the likelihood or hasten the onset of Alzheimer's, like diabetes and high blood pressure.

As I understand it, one of the reasons GLP-1 agonists seem to affect so many different things is that evolutionarily, it does not seem at all surprising that a huge number of things are hooked on the hungry/full signal.

It appears that it might be even more generically the "need/satiated" signal.

Maybe because poor diet has been linked to alzheimers?

I kind of think if it fixes a fundamental issue - too much weight.

Another problem it seems to help with is addictive/impulsive behavior. This might lead to wrong choices in diet or activity.

I suspect that many many functions of the body are degraded or disabled by too much weight or wrong choices, and fixing those problems might let the body cure and maintain itself properly.

Obesity may increase the risk of Alzheimer's but it's far from a requirement for the disease. I can't find a link between Alzheimer's and being overweight except in case of obesity.

https://www.alzheimers.org.uk/about-dementia/managing-the-ri...

I read this[1] some time ago. Seems relevant now.

- [1] https://www.astralcodexten.com/p/why-does-ozempic-cure-all-d...

The article describes data showing a correlation between Ozempic use and slowed progression of certain brain conditions. The study aimed to determine whether that effect came from Ozempic itself or simply from weight loss. Once researchers controlled for weight loss, the effect disappeared. In other words, correlation, not causation.

Since Ozempic was the primary reason for the weight loss, it's still causation. Although indirect.

That's an important caveat. But effectively it sounds like Ozempic typically results in a better diet, and a better diet typically results in slowed progression.

A lot of medical research is "x is correlated with y and we have no idea why".

"Alleged magic cure does not solve all our problems" just isn't as catchy.

It's disappointing to the manufacturers and consumers because many boomers are taking it already to treat 40+ years of poor and/or indulgent consumption (and more will now that they've negotiated a price reduction).

Glp-1 drugs inhibit drinking and compulsive behaviors and I'm not sure the mechanism of action is known

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