
Link Between Alzheimer’s and Herpes - pingou
https://www.theatlantic.com/science/archive/2018/07/herpes-viruses-alzheimers/564887/?single_page=true
======
nonbel
These headlines are horrible. The actual story is about "Amyloid Beta, the
substance currently thought to cause Alzheimer's, may actually protect against
Alzheimer's and herpes".

> _" Robert Moir, a neurologist at the MassGeneral Institute for
> Neurodegenerative Disease, says that many researchers have cast it as a
> villainous molecule with no beneficial function. “It’s just bad, bad, bad,”
> he says. “But it has become increasingly obvious that this isn’t true.” Moir
> thinks that amyloid beta has a more heroic role, as a foot soldier of our
> immune system. It protects neurons from infectious microbes—and from herpes
> viruses, in particular."_

~~~
LordDragonfang
Further down in the article:

> _" In the past three decades, more than 100 papers have described
> correlations between the presence of HSV–1 and the risk of Alzheimer’s...
> Most recently, Ben Readhead and his colleagues at the Icahn School of
> Medicine at Mount Sinai showed that two herpes viruses, HHV–6A and HHV–7,
> were more common in the brains of Alzheimer’s patients than in those of
> healthy people."_

And the article continues to point out the links, though hedges as to whether
it is a causal link or not in either direction.

~~~
nonbel
The presence of a correlation isnt the interesting part of the story (as noted
by others, what isnt correlated with Alzheimer's?), so should not be
highlighted in the headline. The interesting part is the proposal that amyloid
beta is protective.

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asciimo
There are so many links to Alzheimer's lately that I'm not sure there's a
reasonable prevention strategy.

~~~
baxtr
67% of all humans carry HSV-1. I don’t think there is much prevention you
could do

[http://www.who.int/news-room/fact-sheets/detail/herpes-
simpl...](http://www.who.int/news-room/fact-sheets/detail/herpes-simplex-
virus)

~~~
sametmax
What we can do is realize that HSV-1 is not the problem.

The fact that some individuals' immune system let it through hint that there
is a more important causal issue somewhere.

Herpes may be a simple symptom, not a disease.

And maybe it's a symptom of a condition that is similar to the one that let
Alzheimer’s set in.

Who knows, maybe Alzheimer's is a symptom too of a more deep, complex and
subtitle disorder.

~~~
StavrosK
This made me realize that future humans will view our understanding of
Alzheimer's the way we view people's understanding of AIDS in the 60s. "You
mean they were getting Alzheimer's left and right, and they hadn't noticed it
was caused/transmitted by X?!"

Assuming there's some preventable cause or vector, anyway.

~~~
jacobolus
Nitpick: AIDS wasn’t really noticed at all in the US until the beginning of
the 1980s,
[https://en.wikipedia.org/wiki/History_of_HIV/AIDS](https://en.wikipedia.org/wiki/History_of_HIV/AIDS)

~~~
ams6110
Prior to the late 1970s / early 1980s, the stigma associated with
homosexuality was much stronger. Being gay, and having multiple sex partners,
was something that most gay men would probably not admit to. In many areas it
would be admitting to a crime. So in the case histories of early AIDS
sufferers, that commonality may not have been clear.

------
vfc1
Apparently the brains of Alzheimers patients are full of plaque similar to
arterosclorosis - [https://nutritionfacts.org/topics/alzheimers-
disease/](https://nutritionfacts.org/topics/alzheimers-disease/)

Probably for most of us its more important to undertand that genes are not a
death sentence, they are triggered by environmental factors.

Obesity is also genetic, some persons body cant cope with the standard western
diet.

But if they adapt their diet they will most likely never get obese, and get
heart disease and diabetes as a result.

Your thoughts?

~~~
TangoTrotFox
Obesity is almost never genetic. There are a tiny handful of genetic
conditions for which obesity can emerge as a side effect, but in the vast
majority of cases obesity is simply the result of consuming too many calories.
[1]

I don't think a source should be necessary for this, though I did bother to
include one. Obesity hardly existed in e.g. the fifties, and that was
certainly not for a shortage of food. And the individuals of healthy weight
did reproduce, in great numbers. The sudden emergence of a massive genetic
disorder makes no sense.

On the other hand people started becoming fat once quick, cheap, food that
sacrifices healthfulness for flavor and price became ubiquitous. And in
contemporary times we've subsidized the pants off corn resulting in things
like high fructose corn syrup being in practically everything. And of course
it would be remiss to not consider the great changes in the engineering of
foodstuffs and the corresponding change in the status quo of herbicides with
us also consuming trace amounts in massive quantities, as a generational
experiment.

[1] -
[https://www.cdc.gov/genomics/resources/diseases/obesity/inde...](https://www.cdc.gov/genomics/resources/diseases/obesity/index.htm)

------
titzer
It seems possible that Alzheimer's is not a single disease, but a cluster (or
a class) of diseases that have very similar symptoms and effects on neurology.
Many causes, one manifestation, like cancer.

~~~
nonbel
This is where biomedical theories go before they die. "Its so complex there
cant even be a cure by definition, thats why we failed. It has nothing to do
with incorrect usage of statistics, lack of coming up with and testing
quantitative theories, and questionable research practices being standard in
our field."

~~~
pcrh
I agree with you, too bad you've been down-voted...

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dumb2223
All theses studies present many correlations between herpes and Alzheimers.
Perhaps Judea Pearl methods and books could be used to develep medical
studies. What kind of experiments is expected to have the better result for
the minimum cost? I should like to know if this kind of approach is being used
nowadays. Recall that Judea Perl idea is not only to analyze current data but
to design experiments to estimate conditional probability with experiment
designed to test ideas.

------
chiefalchemist
It wasn't clear to me, is amyloid beta role __only__ to protect the brain from
herpes?

Or is there a particular reason the study used that particular herpes virus?
Is that reason scientific or for press release purposes?

If it is amyloid beta's only job, is that typical?

Without amyloid beta what danger, if any, does this herpes virus pose to an
unprotected brain?

Finally, wouldn't this be easy to test / verify in humans? Wouldn't a simple
blood test show herpes or herpes antibodies? And then Alzheimer's?

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alkonaut
If antiviral drugs were cheap enough and free (or nearly free) of side
effects, should we simply start using them daily as we grow older, in parts of
the world where we live long enough?

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hamilyon2
Isn't herpes treatment aciclovir? Cheap and with little side-effects.

~~~
chasil
It likely doesn't cross the blood-brain barrier.

It also wouldn't touch latent virus, only a minority that were actively
replicating.

~~~
trendia
"Acyclovir crosses the blood-brain barrier, a desirable quality for the
treatment of herpes encephalitis, neonatal herpes simplex virus infections,
and, possibly, multiple sclerosis" [0]

"The bioavailability of orally administered acyclovir is limited to 15 to 30%
(23), and the level of passage across the blood-brain barrier has been assumed
to be low, probably due to the relatively low lipophilicity of acyclovir (8).
It was previously found (14) that upon oral administration the acyclovir
concentration in cerebrospinal fluid (CSF) is only 13 to 52% of that found in
plasma. When sustained and high concentrations of acyclovir in plasma are
desirable, improved bioavailability can be achieved with valacyclovir, the
hydrochloride salt of the l-valyl ester of acyclovir." [1]

[0]
[http://aac.asm.org/content/54/3/1146.full](http://aac.asm.org/content/54/3/1146.full)

[1]
[https://www.ncbi.nlm.nih.gov/pmc/articles/PMC166099/](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC166099/)

------
olfactory
Is it not obvious that this article is meant to make us imagine beloved elders
as participants in high risk sex?

~~~
dang
Please don't do this here.

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sova
So curing one disease can also cure another...

~~~
freddie_mercury
No. You didn't read the article.

“We can’t make any causal inferences” from these studies, cautions Maria
Carrillo, the chief scientific officer of the Alzheimer’s Association. “Their
findings don’t prove the viruses lead to Alzheimer’s progression, but there is
a relationship, and we need to understand what herpes viruses are doing in the
brain.”

~~~
ItsMe000001
Also, even if there was a deeper cause contributing to both ("causing it" is
much more rare than a common contributing factor) you could cure one bot not
the other if you don't address (or don't even know) that common factor but use
some other path to address one problem even without knowing the full picture.
When (as is common) there are many contributing factors solving one problem
may be done by addressing only one or some of them, and that may not be the
one that also contributes to some other (visible) problem. So "curing one also
cures the other" would only work in an incredibly specific scenario, while
there are many others possible that allow some sort of common factor
somewhere, among many others.

