Monty, aged
12 with ASD, has been taking Atorvastatin for two years, with a clear cognitive
improvement from day one.
This
improvement is lost when this therapy is interrupted.
There are
several posts in this blog giving the scientific basis why statins might be
beneficial in some autism, these included the genes/proteins RAS, PTEN and
BCL2. In addition, statins possess
potent anti-inflammatory properties.
Following a
flood of visits to this blog to read about statins and autism, I did a quick
check and in recent weeks at least three papers have been published suggesting
the potential for statins to improve some autism.
I include the
word “some” because with 800 currently identified autism genes, and I expect
eventually it will be thousands, what works for one person’s “autism” may not
help the next person’s “autism” and might even make it worse.
The first
paper is the one getting the media coverage, it is from the University of
Edinburgh, plus Mark Bear et al from MIT.
Mark Bear’s lab has featured in this blog several times, particularly
relating to Fragile-X. Lovastatin is
being already trialed in humans with Fragile-X.
I use
Atorvastatin (Lipitor) because it has best side effect profile. Lovastatin and Simvastatin will have the same
effect. In some countries these drugs are
available cheaply OTC.
Their therapeutic effect in autism, based on my sample of one, is from the first
pill.
Over to the "experts":-
Intellectual disabilities and
autism spectrum disorders could share similar defects although their genetic
causes are different, according to Scottish scientists.
A study of
two models of intellectual disability in mice by Edinburgh University has found
that they share similar disease mechanisms.
Researchers
also found that treatment with a statin drug called Lovastatin, which is often
used to treat high cholesterol, can correct high levels of protein production
in the brain linked to the conditions.
The findings suggest that different types of intellectual disabilities may
benefit from common therapeutic approaches, the researchers say.
Professor
Peter Kind, Director of the University of Edinburgh’s Patrick Wild Centre for
Research into Autism, Fragile X Syndrome and Intellectual Disabilities, said:
“Statins, such as lovastatin, are already used widely for treating people,
including children, for high cholesterol with minimal side effects.
“Further
studies are needed to determine whether these existing medications could also
help people with intellectual disabilities.”
The study
has been published in the Journal of Neuroscience
The
full paper is here:-
Abstract
Previous studies
have hypothesized that diverse genetic causes of intellectual disability (ID)
and autism spectrum disorders (ASDs) converge on common cellular pathways.
Testing this hypothesis requires detailed phenotypic analyses of animal models
with genetic mutations that accurately reflect those seen in the human
condition (i.e., have structural validity) and which produce phenotypes that
mirror ID/ASDs (i.e., have face validity). We show that SynGAP
haploinsufficiency, which causes ID with co-occurring ASD in humans, mimics and
occludes the synaptic pathophysiology associated with deletion of the Fmr1
gene. Syngap+/− and Fmr1−/y mice
show increases in basal protein synthesis and metabotropic glutamate receptor
(mGluR)-dependent long-term depression that, unlike in their wild-type
controls, is independent of new protein synthesis. Basal levels of
phosphorylated ERK1/2 are also elevated in Syngap+/−
hippocampal slices. Super-resolution microscopy reveals that Syngap+/−
and Fmr1−/y mice show nanoscale alterations in
dendritic spine morphology that predict an increase in biochemical
compartmentalization. Finally, increased basal protein synthesis is rescued by
negative regulators of the mGlu subtype 5 receptor and the Ras–ERK1/2 pathway,
indicating that therapeutic interventions for fragile X syndrome may benefit
patients with SYNGAP1 haploinsufficiency.
SIGNIFICANCE
STATEMENT As the genetics of intellectual disability (ID) and autism spectrum
disorders (ASDs) are unraveled, a key issue is whether genetically divergent
forms of these disorders converge on common biochemical/cellular pathways and
hence may be amenable to common therapeutic interventions. This study compares
the pathophysiology associated with the loss of fragile X mental retardation
protein (FMRP) and haploinsufficiency of synaptic GTPase-activating protein
(SynGAP), two prevalent monogenic forms of ID. We show that Syngap+/−
mice phenocopy Fmr1−/y mice in the alterations in
mGluR-dependent long-term depression, basal protein synthesis, and dendritic
spine morphology. Deficits in basal protein synthesis can be rescued by
pharmacological interventions that reduce the mGlu5 receptor–ERK1/2
signaling pathway, which also rescues the same deficit in Fmr1−/y
mice. Our findings support the hypothesis that phenotypes associated with
genetically diverse forms of ID/ASDs result from alterations in common
cellular/biochemical pathways.
A drug that blocks a cancer-related pathway normalizes neuron number and
prevents behavior problems in mice that lack a copy of the autism-linked
chromosomal region 16p11.2.
Researchers presented the unpublished results yesterday at the 2015 Society for Neuroscience annual meeting in Chicago.
Loss of 16p11.2 results in intellectual disability, enlarged head,
obesity and, often, autism. This region spans 27 genes — including one called
ERK1, part of a signaling cascade that regulates cell growth. The cascade,
called the RAS pathway, is hyperactive in some types of cancer and in four rare autism-linked neurodevelopmental disorders,
collectively dubbed ‘RASopathies.’ The proteins encoded by ERK1 and the related
ERK2 gene carry out many of the molecular consequences of RAS pathway
activation.
Paradoxically, the ERK proteins are hyperactive in mice lacking a copy
of 16p11.21.
This hyperactivation coincides with a period of intense neuron development in
the mouse embryo. The animals also have too few neurons in some parts of the
cerebral cortex, the brain’s outer layer, and too many neurons in others.
“Because of this aberrant ERK hyperactivity, we were thinking that we
can potentially try to bring the levels down by using a specific ERK
inhibitor,” says Joanna Pucilowska, a postdoctoral fellow in Gary
Landreth’s lab at Case Western Reserve University in Cleveland,
Ohio.
Sniffing clues:
Pucilowska and her colleagues used an experimental drug that blocks
activation of the ERK proteins. They injected the drug into pregnant mice to
investigate its effects on neuron development in mouse embryos.
Treating mice with the drug prenatally for five days stabilizes ERK
activity, the researchers found. It also normalizes neuron numbers in the
cerebral cortex.
The treatment has lasting effects on behavior, too. Unlike untreated
mice that lack a copy of 16p11.2 — which are underweight, hyperactive and have
memory problems — the treated mice resemble those that do not have the
chromosomal deletion.
The researchers discovered for the first time that mice lacking 16p11.2
are quicker than those without the deletion to sniff out a hidden snack in
their cage, suggesting they have a highly acute sense of smell, like some
people missing 16p11.2. Female mice with the deletion are also faster to
retrieve pups that stray from the safety of their nest, an innate maternal
behavior. The drug treatment normalizes both behaviors.
Pucilowska says she and her colleagues would like to test the drug in
cells derived from people missing a copy of 16p11.2. If it works in human cells the same way it does
in mice, then it might be possible to treat people with the deletion using
cholesterol-lowering drugs called statins, which are also known to block
signaling in the RAS pathway. “This can potentially lead to the first
treatment for children with 16p11.2 deletion,” Pucilowska says.
Structural changes in the
connections between neurons may underlie the enhanced learning and motor skills
seen in mice with an extra copy of the autism-linked gene MeCP2. Blocking these changes with a drug blunts the animals’
performance.
The findings, presented yesterday
at the 2015 Society for Neuroscience annual meeting
in Chicago, point to neural mechanisms underlying the restricted interests and,
in some cases, exceptional learning abilities seen in people with autism.
“This could lead to enhanced
learning and enhanced performance in constrained behaviors, like in autistic
savants,” says Ryan Ash, a graduate student in Stelios Smirnakis’ lab at Baylor College
of Medicine in Houston. “Maybe they can’t iteratively refine those kinds of
behaviors over time, so they get stuck in a behavior, which can be exceptional
in certain cases but then impaired in others.”
People carrying an extra copy of MeCP2 often have autism. Mice with the
same duplication have autism-like symptoms, such as avoiding social
interactions with other mice.
“But they also have a
super-learner phenotype,” Ash says. They perform better than controls do on a
test of motor skill learning that involves balancing on a rotating rod. Typical
mice fall off the rod as its speed increases, but mice with the duplication
learn to coordinate their feet so that they can stay on about 30 seconds
longer.
When mice learn a motor task, new
synapses, connections between neurons, form in the brain1.
The researchers suspected that the superior learning abilities of the mice
carrying the extra MeCP2 might stem from alterations in the formation and
stability of these neuronal links.
To test this hypothesis, the
researchers used microscopy to image neurons in the brain that connect to the
spinal cord and control movement. They took pictures of the same neurons before
and after the mice practiced the rotating rod test for four days, and again
after the animals had four days of rest.
Spine support:
As expected, training spurred
neurons in typical mice to form new signal-receiving projections, called
dendritic spines. About half of these spines remained after four days of rest,
suggesting the formation of stable memories. Mutant mice form more spines than
controls do, and more of them stay put after the mice take a break.
The stable spines tend to
cluster. Enhanced performance on the rod tracks with a greater number of
clustered spines remaining after the rest period.
“We think this is important
because spines that are near each other can drive the cell more strongly when
they get activated at the same time,” Ash says.
Training stimulates greater
activation of a signaling cascade called the RAS pathway in the mutant mice
than it does in controls. Activation of this pathway is known to strengthen
clustered spines2.
Blocking the activation of this
pathway with an experimental drug called SL327 lowers the mutants’ performance
on the rotating rod back to the normal range. And the spines in these animals
also look more like those of typical mice.
The findings suggest that spine formation and stability underlie the
enhanced learning abilities of the mutant mice. Both processes appear to depend
on the activation of the RAS pathway.
The drug the researchers used lasts only for a few hours, so it is not
likely to help people with autism, Ash
says. But
cholesterol-lowering drugs called statins block activation of the same pathway
by a different mechanism. “Maybe you could do a more chronic treatment with a
statin, but we haven’t tried that yet,” he says.
Other mouse models of autism show
enhanced performance on the rotating rod test. These include mice with a
duplication in chromosomal region 15q11-13 and with mutations in the CNTNAP2, NLGN3 and NRXN1 genes, Ash says.
Interestingly, mice that lack a copy of MeCP2 — the gene mutated in the
autism-linked disorder Rett syndrome — have impaired performance on the same
test, and show reduced spine stability. “I
would hypothesize that all of these things are actually the opposite in the
Rett mice,” Ash says.