When I first
started this blog and my investigation into the biology of autism, I did shy
away from the more complex areas like genetics.
I assumed that this would be best left to the “experts” and be beyond
the powers of those without fancy laboratory tools.
My
literature review took me early on to oxidative stress and then
neuroinflammation. I deduced that in the
case of neuroinflammation, it might be possible to control inflammatory
cytokines using statins. I also noted the use of statins in TBI (Traumatic Brain Injury). I thought it
would be harmless to do a quick trial, not really expecting anything to happen;
but it did, and from the very first dose.
The
literature is full of references to lipid dysfunction in autism and one large
sub-group in autism is known to have high cholesterol. Cholesterol and inflammation are now known to
go hand in hand. When inflammation is
present, the body can react by laying down a protective layer of
cholesterol. The problem is that too
much cholesterol is not good for you either.
The real culprit is not the cholesterol, it is the inflammation.
If you are
in the high cholesterol autism group, a cholesterol lowering drug that is also
anti-inflammatory may be “just what the doctor ordered”.
Be warned
that another subgroup in autism has very low cholesterol. In a study at the Kennedy Krieger Institute,
19% of children had extremely low cholesterol, meaning lower than 99% of
typical children.
There is a
rare condition, leading to autism called Smith-Lemli Opitz syndrome (SLOS).
SLOS is caused by a mutation in an
enzyme involved in cholesterol synthesis; the resulting biochemical
characteristics may be predictable. Most patients have lowered plasma
cholesterol levels.
Since
cholesterol testing is cheap and widely available, you can easily determine
which group you are in.
This post is
for the high cholesterol cohort.
Note well how meaningless a figure for the "average cholesterol level" in autism would be. In the autism literature they frequently take the mean average for all data, thus missing the point.
Why Statins for Autism?
My initial
logic was that since inflammatory markers are often elevated in autism and that oxidative stress and inflammation are self-reinforcing, it would be logical to
find an effective anti-inflammatory agent.
Steroids might fit the bill, but they cause plenty of side effects in
long term use; their short term use in autism can be remarkably effective. So I looked further, and having screened the literature, ended up convincing
myself of the potential of statins. Read
all about cytokine storms in the old posts, if you are interested.
I choose Atorvastatin (also known as Lipitor or Sortis),
since it freely crosses the blood brain barrier (BBB) and is safely used my
tens of millions of people around the world.
It worked.
Explaining Statin Therapy to others.
The most
important thing is to have a therapy that works; but then you have to explain it to others.
I was recently
explaining it again to a doctor relative, who was asking how I could be sure it
works. I explained that every time I
stop using it, within a day behaviour changes in the same predictable way. It is as if people with autism have an inhibitory
barrier; there are things they can do, want to do, but something is blocking
them from doing them.
Examples are
numerous. Speech being one. Plenty of kids with autism are non-verbal,
everything is physically functional, yet they do not talk, even when they want
to communicate.
At the age
Monty, now aged 11 with ASD, tried the statin he was relatively verbal. The immediate change in him was that he
suddenly started to play the piano, by himself.
Odd it may sound.
In his
earlier years he would often get “stuck”.
He would be upstairs and unable to come downstairs, somebody had to go
up and get him.
When I now
stop the statin, he will again get “stuck”.
He will stand in the kitchen and want to leave and just say “go that
way”, but not move. You have to take his
hand, so that he can “go that way”.
A Better Explanation?
Now I have
another explanation of why statins may be effective in one large sub-group of
autism.
Statins up-regulate
a known key dysfunctional autism gene, and protein, called PTEN. I mentioned PTEN in a previous post, since
one chemical released by eating broccoli also up-regulates PTEN.
Science has
already shown that things that down-regulate PTEN (like seizures) make autism
worse.
The full
science behind PTEN will come in a later post.
Statins and Cancer
Regular
readers will recall that PTEN is also a tumor suppressor gene and is therefore
a target for cancer research.
Thinking the
way I do, I know that statins increase PTEN and that this should slow cancer
growth. Hundreds of millions of people
take statins and many millions get cancer, so what about people on statins
getting cancer?
A quick
check on google and there we have studies showing that people on statins get
less cancer and that in common cancers like that of the prostate, the outcome
is better when statins are taken.
Now this is
not a cancer blog, but you do not have to dig very deep to uncover a wealth of
supporting evidence.
Conclusion
In this retrospective cohort of men undergoing RP,
post-RP statin use was significantly associated with reduced risk of BCR.
Whether the association between post-RP statin use and BCR differs by race
requires further study. Given
these findings, coupled with other studies suggesting that statins may reduce
risk of advanced prostate cancer, randomized controlled trials are warranted
to formally test the hypothesis that statins slow prostate cancer progression.
Conclusions This meta-analysis suggests that statin is associated with a
significant risk reduction of liver cancer when taken daily for
cardiovascular event prevention. However, this preventive effect might be
overestimated due to the exposure period, the indication and contraindication
of statins and other confounders. Statins might be considered as an adjuvant in the treatment of liver
cancer.
Statins and PTEN
I am no
cancer expert, but I can read the literature and the evidence is pretty
compelling to me. It is not enough, however, for doctors to prescribe statins to avoid cancer. They are so busy prescribing statins to over 50s for other reasons, it does not really matter.
We came
across PPAR previously. PPAR gamma is a
pathway to treat type 2 diabetes and the old type 2 diabetes drug Pioglitazone
has shown promise in an autism study.
Effect of pioglitazone treatment on behavioral symptoms in autistic children
At that time
I was more interested in PPAR-alpha, due to its role in mast cell
stabilization.
It is via
PPAR-gamma, that statins up regulate PTEN.
You do not want
to overdo it, because at very high doses too much PPAR gamma protein will be
produced and you risk causing type 2 diabetes.
Low doses of
statins are trouble free for most people, but high doses are associated with
increased risk of diabetes and all kinds of aches and pains.
The statin
effect in autism does not increase with higher doses, only a small dose is
required.
Abstract
Germline
mutations in the tumor-suppressor gene PTEN predispose to heritable breast
cancer. The transcription factor peroxisome proliferator-activated
receptor-gamma (PPARgamma) has also been implicated as a tumor suppressor
pertinent to a range of neoplasias, including breast cancer. We previously demonstrated that
lovastatin may signal through PPARgamma and directly upregulate PTEN expression
at the transcriptional level. In our current study, we show that simvastatin,
pravastatin and fluvastatin can induce PTEN expression in a dose-dependent
manner. This resulted from an increase in PTEN mRNA indicating
transcriptional upregulation. In addition, we observed, for the first time,
that upregulation of sterol response element-binding protein (SREBP), known to
induce PPARgamma expression, can increase PTEN expression. Using reporter
assays, we observed that both the statins and SREBP could specifically induce
PPARgamma-mediated transcription. However, the statins do not appear to signal
through SREBP. Furthermore, our results indicate that SREBP utilizes
PPARgamma's transcriptional activity to induce PTEN transcription, whereas the statins signal
through PPARgamma's protein activity to upregulate PTEN expression.
Overall, our observations suggest that statins signal through another
transcription factor, in a PPARgamma-dependent manner, which in turn induces
PTEN transcription. We, therefore, studied the full-length PTEN promoter
through serial deletion reporter assays and electromobility shift assays and
identified a region between -854 and -791 that binds an as-yet-unidentified
transcription factor, through which the statins induce PTEN expression. Since PTEN is constitutively
active, our data indicate it may be worthwhile to examine statin and SREBP
stimulation as mechanisms to increase PTEN expression for therapeutic and
preventative strategies in cancer, diabetes mellitus and cardiovascular disease
PTEN dysfunction in Cancer and Autism
I will cover
this point in more detail in the post on PTEN, but note that the PTEN gene
dysfunctions found in 10% of people with autism are generally different to the
ones found in cancer. We also have the
difference between whether the PTEN gene is mutated or there is PTEN loss.
There should
be two identical copies of the PTEN gene. When one copy is mutated, the protein
it produces was found to inhibit the protein produced by the good copy. In other
cases, one copy of the PTEN gene is OK, but the other got deleted. This turned
out to be better than having one mutant version.
Different
mutations in PTEN are linked to different outcomes. The known autism mutations are called H118P,
H93R and H123Q. If you have a C124S
mutation you would be at risk of something called thyroid
follicular carcinoma and not autism.
It is all very complicated and I have to say some conclusions in the
research are contradictory.
But it is
reported that about 10% of people with autism have an identifiable PTEN
mutation. I am more interested in whether
PTEN is an interesting protein in the other 90%.
We saw in
the fragile X research that even though this affects only 1% of cases with
autism, some experimental therapies for fragile X worked on people with autism,
but without fragile X. At the time I
thought that very odd.
My
assumption is that PTEN is interesting for more than the 10%.
Conclusion
So there are
now 2 plausible reasons why statin therapy may be effective in people with
classic autism and elevated cholesterol:-
· Reduction in inflammatory cytokines
· Up-regulation of PTEN
Maybe it is
both.
It may be
that in people with autism and low cholesterol, and so not suited to statins,
they may also have low levels of PTEN.
We saw in a
recent post that when you eat fresh broccoli in addition to Sulforaphane, you
also produce Indole-3-carbinol (I3C). I3C also
up-regulates PTEN.
Using Peter logic, if statins
have an immediate effect then quite likely so would I3C.
Whatever Next?
Well, for those few of you who
have discovered the “magical” beneficial effects of mast cell stabilizers, like
Verapamil and Cromolyn Sodium, on both autistic behaviours and severe
allergies, here is a preview of what is coming next:-
Recent studies have indicated that PPAR-gamma plays an
important role in anti-inflammatory responses and that PPAR-gamma signaling is
associated with regulation of PTEN expression. It is known that up-regulation
of PTEN expression reduces asthmatic pathogenesis.
These findings suggest that PPAR-gamma uses PTEN to
modulate asthmatic responses The signaling mechanism by which stimulation of
PPAR-gamma
with
the agonists regulates PTEN expression as well as Akt phosphorylation remains
to be lucidated. However, our results agree with the observation that the
anti-inflammatory action of PPAR-gamma agonists is
mediated via up-regulation of PTEN.
In other words, increasing
PTEN minimizes allergies. Perhaps, via
feedback loops, increasing allergies reduces PTEN?
Seizures also reduce PTEN.
Reduced PTEN leads to
increased autistic behaviours.
Not surprisingly we will come
back, yet again, to mast cells.