4 ms·

My understanding was the beta-amyloid hypothesis itself is under some amount of scrutiny and may not truly explain Alzheimer's. Wonder if this finding adds more

by rajup 3y ago

My understanding was the beta-amyloid hypothesis itself is under some amount of scrutiny and may not truly explain Alzheimer's. Wonder if this finding adds more evidence for the amyloid hypothesis.

Mistletoe 3y ago
I thought CJD was caused by a prion. Was it in the growth hormone prep from the cadavers?
- treyd 3y ago
  Yeah that's correct. The article mentions a few cases of people who died from transmitted CJD that may have also received some beta amyloid or tau proteins that could have catalyzed development into Alzheimer's if only they didn't die from CJD, which seems to develop more quickly through that route. If Alzheimer's is truly is some kind of prion-related disease, which the research is suggesting.
- kibibu 3y ago
  From the article: > In the interim, scientists had discovered that that type of hormone treatment they got could unwittingly transfer bits of protein into recipients’ brains. In some cases, it had induced a fatal brain disease called Creutzfeldt-Jakob disease, or CJD — a finding that led to the banning of the procedure 40 years ago.
- caycep 3y ago
  there's transmissible CJD, but most cases are a genetic version where you get the prions from your own cells and then it cascades, if I recall
m3kw9 3y ago
Not sure why scientists has to pin point a single cause where as you have different vectors that can cause the same disease is also plausible
- pedalpete 3y ago
  Or that we've been lumping multiple different types of cognitive decline as a single disease.
  - hmottestad 3y ago
    Can’t you make a definitive diagnosis from an autopsy. Could be that multiple diseases lead to the same findings in the autopsy. While someone is alive a diagnosis of Alzheimers is more of a diagnosis of elimination. There are several drugs that can be used to slow the progression and I assume that those have a role to play in solidifying the diagnosis.
    - hackernewds 3y ago
      That ventures wildly into whether the realm of physicalism explains malaises that happen in the "consciousness" realm. spooky
    - tsimionescu 3y ago
      You can check for amyloid plaques in an autopsy, but apparently plenty of old people that show no significant cognitive decline also have amyloid plaques. So, while we would definitively call it Alzheimer's if you have significant cognitive decline + amyloid plaques, it's not 100% clear that this is a single diagnostic.
- arcticfox 3y ago
  They don't, but my surface understanding is that the medicines that effectively nuke beta amyloid have no effect overall. Which would mean it's not even one of many causes, it seems to not be a cause at all.
  - tim333 3y ago
    I think the medicines likely reduce beta amyloid rather than get rid of all of it which if it has a prion like mechanism wouldn't really fix things.
scythe 3y ago
This finding definitely supports a brain protein hypothesis, but it could just as easily point to tau protein as amyloid. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3399531/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3399531/
xenadu02 3y ago
The short version as I understand it: amyloid plaques are a symptom but not a cause. There was a theory floating around that they're a neurological immune response to viral infection but I don't think there's enough evidence to prove that yet.

by rajup 3y ago

My understanding was the beta-amyloid hypothesis itself is under some amount of scrutiny and may not truly explain Alzheimer's. Wonder if this finding adds more evidence for the amyloid hypothesis.

Mistletoe 3y ago

I thought CJD was caused by a prion. Was it in the growth hormone prep from the cadavers?

treyd 3y ago
Yeah that's correct. The article mentions a few cases of people who died from transmitted CJD that may have also received some beta amyloid or tau proteins that could have catalyzed development into Alzheimer's if only they didn't die from CJD, which seems to develop more quickly through that route. If Alzheimer's is truly is some kind of prion-related disease, which the research is suggesting.
kibibu 3y ago
From the article: > In the interim, scientists had discovered that that type of hormone treatment they got could unwittingly transfer bits of protein into recipients’ brains. In some cases, it had induced a fatal brain disease called Creutzfeldt-Jakob disease, or CJD — a finding that led to the banning of the procedure 40 years ago.
caycep 3y ago
there's transmissible CJD, but most cases are a genetic version where you get the prions from your own cells and then it cascades, if I recall

m3kw9 3y ago

Not sure why scientists has to pin point a single cause where as you have different vectors that can cause the same disease is also plausible

pedalpete 3y ago
Or that we've been lumping multiple different types of cognitive decline as a single disease.
- hmottestad 3y ago
  Can’t you make a definitive diagnosis from an autopsy. Could be that multiple diseases lead to the same findings in the autopsy. While someone is alive a diagnosis of Alzheimers is more of a diagnosis of elimination. There are several drugs that can be used to slow the progression and I assume that those have a role to play in solidifying the diagnosis.
  - hackernewds 3y ago
    That ventures wildly into whether the realm of physicalism explains malaises that happen in the "consciousness" realm. spooky
  - tsimionescu 3y ago
    You can check for amyloid plaques in an autopsy, but apparently plenty of old people that show no significant cognitive decline also have amyloid plaques. So, while we would definitively call it Alzheimer's if you have significant cognitive decline + amyloid plaques, it's not 100% clear that this is a single diagnostic.
arcticfox 3y ago
They don't, but my surface understanding is that the medicines that effectively nuke beta amyloid have no effect overall. Which would mean it's not even one of many causes, it seems to not be a cause at all.
- tim333 3y ago
  I think the medicines likely reduce beta amyloid rather than get rid of all of it which if it has a prion like mechanism wouldn't really fix things.

scythe 3y ago

This finding definitely supports a brain protein hypothesis, but it could just as easily point to tau protein as amyloid. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3399531/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3399531/

xenadu02 3y ago

The short version as I understand it: amyloid plaques are a symptom but not a cause. There was a theory floating around that they're a neurological immune response to viral infection but I don't think there's enough evidence to prove that yet.