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Comment by bjourne | Hacker News Reader

Afaict, this is not an entirely new finding. For example, this page (https://www.nature.com/articles/d41586-018-07771-6) references a 2018 article about the issue of Alzheimer's being transmitted (or rather "seeded") through growth hormone extracted from cadavers. Perhaps the new article provides additional evidence or perhaps the other article only suspected a casual link and this one proves that there is one. I haven't read it thoroughly.

What I find interesting and scary is the "seeding" part. The small amount of growth hormone injected to the children cannot itself have caused Alzheimer's. But it must have caused some rewiring of the brain to make it accumulate more plaque which over a period of many decades slowly decreased their brain performance. If this effect is synthesizeable then one can easily imagine many countries using it to develop terrifying biological weapons.

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It mentions brain proteins contaminating it, makes me think of prions.

Yeah, these paragraphs from the paper sounds like the amyloid proteins can sometimes look/act like a prion if you squint:

> The far wider relevance of prion mechanisms was first exemplified with the discovery of yeast prions but has also widened considerably with the recognition that the more common human neurodegenerative diseases, including Alzheimer’s and Parkinson’s diseases, involve accumulation and spread of assemblies of misfolded host proteins in what is often described as a ‘prion-like’ fashion with experimental transmission of relevant pathology in primates or mouse models. However, the importance for human disease was unclear until the recognition of human transmission of amyloid-beta (Aβ) pathology via iatrogenic routes after prolonged incubation periods, causing iatrogenic cerebral amyloid angiopathy (CAA) and raising the possibility that iatrogenic Alzheimer’s disease may occur at even longer latency.

The thing is (despite popular misconception that prions are common and many proteins that can turn into prions), there is only a specific protein that can be a prion- the PrP protein.

https://en.wikipedia.org/wiki/Major_prion_protein

Demonstrating "some other other protein behaving like a prion" is close to nobel prize territory.

Perhaps a first pass research question is:

Do people who undergo spinal, brain, retinal surgery have a higher incidence of Alzheimer when compared with the rest of the population?

Otherwise there is no point in chasing this "some other other protein behaving like a prion" avenue.

>Do people who undergo spinal, brain, retinal surgery have a higher incidence of Alzheimer when compared with the rest of the population?

In that case scarring/inflammation might trigger the Alzheimer's though. The interesting part in this article is that the growth hormone was not injected into brain tissue I assume.

There are quite a lot of diseases where a prion like mechanism is suspected https://en.wikipedia.org/wiki/Prion#In_other_diseases

ie. some protein other than PrP gets misfolded and then acts as a template to cause more misfolding. I've read up a bit on ALS as my sister has it and while it's not fully understood the most likely cause seems misfolding of a proteins called or TDP-43 or SOD1. Eg from a paper:

>recent cultured cell line and animal model studies suggest that the misfolded forms of SOD1 and TDP-43 do self-propagate within neuronal cells and transmit to neighboring cells https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4363329/

Wikipedia seems to say there's another one:

>All known mammalian prion diseases were caused by PrP until 2015, when a prion form of alpha-synuclein was hypothesized to cause multiple system atrophy (MSA).[10]

https://en.wikipedia.org/wiki/Prion

The article mentions that the procedure was banned due to incidence of Creutzfeldt-Jakob disease. That is a prion disease.

They still use pieces of cadaver for other surgeries. E.g. gum and bone transplants done by periodontists. Seems risky to me.

as long as it’s not spine or brain matter it’s probably okay. During the mad cow outbreak (BSE, the bovine equivalent of CJD) in the UK, they banned “beef on the bone” but not all beef.

And CJD came about from farmers using ground and processed cow brains to feed cows. What could possibly go wrong feeding a cow some cow brains!

It is worse than that - it first made the jump to cows when condemned sheep, infected with the similar prion disease 'scrapie', were ground up and fed to cows.

There's a human prion disease, kuru, which was caused by the practice of funerary cannibalism - where family would ritually consume parts of their deceased relatives' bodies.

The moral of the story seems to be, don't eat brains.

Which is rather unfortunate.

I no longer eat meat, but when I was younger I considered the brains as the tastiest part of an animal, when properly prepared and cooked.

It is said that in USA eating organs is not very popular, so it is likely that many have never experienced well cooked brains, to know what they are missing.

There exists a hypothesis that is rather plausible, that breaking bones and eating their content of brains and marrow has played an important role in the evolution of humans, by providing an abundant source of long-chain fatty acids, enabling the unusual mass ratio between the central nervous system and the whole body that characterizes humans.

Brains, cooked contains 210 calories per 140 g serving. This serving contains 15 g of fat, 16 g of protein and 2.1 g of carbohydrate. The latter is 0 g sugar and 0 g of dietary fiber, the rest is complex carbohydrate. Brains, cooked contains 3.3 g of saturated fat and 4304 mg of cholesterol per serving.

If you do not have risk factors for heart disease, you should limit your cholesterol intake to no more than 300 milligrams a day.

1000% your rda of cholesterol in a single serving!

Might depend on the age of the patient.

Periodontists have been also linked with a higher number of Alzheimer cases. Is a group of risk in this disease.

The doctor or their patients have the higher risk?

if I remember correctly Dentists had more cases of alzheimer than other groups of doctors. I heard it some time ago.

If is a prion, it should resist most sterilization of dental instruments by heat on autoclave. So is obvious IMAO that this could be a way to spread the disease from one patient to other, but I'm not an expert on clinic procedures and the protocols may have been updated. This is known, or at least suspected, since maybe a decade or so.

>Dentists had more cases of alzheimer than other groups of doctors

Herpes?

1. Travels along nerve cells

2. Causes lifelong infection

3. Can enter the brain (HSV encephalitis)

4. Herpetic whitlow used to be an occupational disease of dental workers (still is to some extent)

"Overwhelming Evidence for a Major Role for Herpes Simplex Virus Type 1 (HSV1) in Alzheimer’s Disease (AD); Underwhelming Evidence against"

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8234998/

do you recall percentages? like 10% higher or 5x higher?

Don't remember, sorry. It was a lot of time ago. The articles should be listed in scientific indexes.

Dentists are a special group that worked a lot with mercury in the past, dunno if is related but it could be a combination of risk factors. We should ask a chemist.

In any case today the facts can be very different.

What I found odd, is in the article it talked of the importance of sterilising medical tools used, that may have had prions on them. Prions can't even be destroyed by extreme temperatures, they are extremely scary.

Over 900c for several hours vs 250 in autoclave... if Alzhaimers can spread this way, i am done, because I spent days in dentist chair...

Prions are exactly the tiny, hard to detect things that could make Alzheimers transmissible. There are likely to remain many questions to resolve, but this sure suggests a line of inquiry: Is Alzheimer's one distinct disease? Can a prion be isolated as the cause? Can a diagnostic test be designed that detects this prion? Etc.

There is no reason to assume this is a matter of proteins.

It could just as easily be viral or bacterial infection. Classically, people always just assumed that brains had no such infections. Until somebody checked, and they turn out to be very common.

But they still don't look for infections in Alzheimer's patients' brains, probably because it would make them seem negligent. (Which they are.)

> There is no reason to assume this is a matter of proteins.

Except that there's increasing evidence that specific proteins do in fact play a part in various forms of dementia.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4072215/

It is possible that Alzheimer's is purely a matter of aberrant proteins. That would be valid conclusion if the evidence turned out to support it. But it is not a valid assumption under any circumstance.

Have they found prions in Alzheimers patients universally? That would seem to have come up looooong ago given how much it has been studied.

Both new and old articles are from the same lab. So they hypothesized it in previous article and now found signs of dementia in some of patients who survived. Still no evidence of actual transmission of A-Beta.

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