More Research to support a Trial of Clemastine in Autism and particularly in Pitt Hopkins

                                                

Clemastine is an old antihistamine drug that we saw in earlier posts can stimulate oligodendrocytes to work harder and produce more myelin.

Myelin is needed to learn new skills and to control your body. It only starts to form in the third trimester, as the brain begins to grow rapidly. Myelination continues after birth but the rate appears to be controlled by social/emotional exposure.  The more isolated the baby is, the less myelin is produced.

                          

https://kids.frontiersin.org/article/10.3389/frym.2018.00020

Interruption of the myelination process is known to cause long term problems.

Loss of myelin and lack of remyelination underlies Multiple Sclerosis.

It appears that loss of myelin may underlie cognitive loss in regressive autism, childhood disintegrative disorder and adult hypoxia.  First the myelin layer is lost and, depending on the underlying dysfunction, the neuron may die.  If it is just a case of lost myelin this can potentially be repaired.

Girls with Rett syndrome regress and lose previously acquired skills at about 18 months.  Is the loss of skills also a manifestation of a loss of myelin?  If so, can this loss of skills be controlled to minimize its effect?

In a previous post we have looked at the repurposing of Clemastine to improve remyelination.  At high doses this is an emerging therapy for Multiple Sclerosis (MS).  MS is a progressive disease where myelin is repeatedly lost.  Myelin is not permanent and constantly needs to be “remyelinated”.

As Ling has noted, the Pitt Hopkins syndrome researchers have published their results looking at mouse models of both Pitt Hopkins and broader autism and they have found that the same oligodendrocyte genes are indeed dysregulated in all these cases.

We already knew that myelin in idiopathic autism is thinner than it should be, which was why I was originally looking at ways to enhance myelination.

The new research gives further support for remyelination as a target for improving learning, cognitive function and motor skills in autism.  The new data shows that this likely particularly applies to those with Pitt Hopkins syndrome.  This syndrome is caused by a lack of Transcription Factor 4 (TCF4) when one of the two copies of its gene is not functional.  A more modest lack of TC4 is likely to be much more common that Pitt Hopkins itself.

Defects of myelination are common pathophysiology in autism spectrum disorder

Autism Spectrum Disorder (ASD) is genetically heterogeneous in nature with convergent symptomatology, suggesting dysregulation of common molecular pathways. We analyzed transcriptional changes in the brains of five independent mouse models of Pitt-Hopkins Syndrome (PTHS), a syndromic ASD caused by autosomal dominant mutation in TCF4, and identified considerable overlap in differentially expressed genes (DEGs). Gene and cell-type enrichment analyses of these DEGs highlighted oligodendrocyte dysregulation and we confirmed the myelin-associated transcriptional signature in two additional mouse models of syndromic ASD (Pten^m3m4/m3m4, Mecp2^tm1.1Bird). We subsequently validated oligodendrocyte deficits in our Tcf4 mouse model which showed inefficient oligodendrocyte maturation in both an isolated oligodendrocyte in vitro cell culture system and ex vivo at day 24 (P24) and day 42 (P42). Furthermore, we used transmission electron microscopy (TEM) to visualize myelination in the corpus callosum (CC) of Tcf4^+/tr and Tcf4^+/+ littermates, observing a significant decrease in the proportion of myelinated axons in the CC of Tcf4^+/tr mice compared to Tcf4^+/+ littermates. Similar to our ex vivo IHC results, we observed a significant reduction in the number of CNP-positive oligodendrocytes in primary cultures derived from Tcf4^+/tr mice compared to Tcf4^+/+ littermates. When comparing compound action potentials (CAP) using electrophysiology, we show the ratio of N1/N2 is significantly reduced in the Tcf4^+/tr mice compared to Tcf4^+/+ littermates, indicative of a greater proportion of CAP traveling down unmyelinated axons. Moreover, we integrated syndromic PTHS mouse model DEGs with human ASD genes (SFARI) and human idiopathic ASD postmortem brain RNA-seq, and found significant enrichment of overlapping DEGs and common biological pathways associated with myelination. Remarkably, we show that DEGs from syndromic ASD mouse models can be used to identify human idiopathic ASD cases from controls. These results from seven independent mouse models of ASD are validated in human brain, implicating disruptions in oligodendrocyte biology as shared mechanisms in ASD pathology.

Here is more on the same paper:-

Loss of insulation on neurons may contribute to autism

Genes involved in the formation of myelin, a fatty substance that sheathes neurons, are altered in brain tissue from autistic people and in several mouse models. The mice also have unusually few myelinated nerve fibers.

Researchers presented the unpublished findings yesterday at the 2019 Society for Neuroscience annual meeting in Chicago, Illinois.

“In general, across the whole spectrum, there’s a defect in myelination,” says Brady Maher, lead investigator at the Lieber Institute for Brain Development in Baltimore, Maryland.

Myelination is the process by which neuronal fibers are coated in myelin. Myelin is made by brain cells called oligodendrocytes, and it enables fast neuronal signaling.

Maher and his colleagues saw hints that myelination is disrupted in Pitt-Hopkins syndrome, an autism-related condition caused by mutations in a gene called TCF4. Children with this rare syndrome are slow to learn to walk, and most are minimally verbal; some have autism.

The researchers analyzed gene expression patterns in five mouse models of this syndrome, each with a different mutation in TCF4. They found that in all of the mice, genes involved in myelination are among those with altered expression.

The researchers then compared gene expression patterns of the mutant mice with those of two other autism mouse models: mice with mutations in MECP2 or PTEN. All three mouse models show alterations in the expression of a shared set of 34 genes, most of which are involved in myelination.

The same genes show atypical expression in two independent gene-expression datasets from autistic people, the researchers found.

Maher says his team is investigating why the TCF4 mutant mice have too few oligodendrocytes. They are also testing whether drugs that enhance myelination reverse the mice’s problems.

Clemastine in Autism

Several readers of this blog have reported a positive effect from Clemastine, you can find their comments in earlier posts.

Monty, aged 16 with ASD, has been using it for many months and it will be added to my Polypill at the next update.

In the US Clemastine is no longer available in the OTC form.  It is available as a generic with a prescription

https://www.tevagenerics.com/product/clemastine-fumarate-tablets-usp

In the rest of the world it is called Tavegil, or Tavegyl and being a common hay fever drug is usually OTC (no prescription).

In the Baltic states 20 tablets cost Eur 5 (USD 5.50). In the United Kingdom 60 tablets costs GBP 10 (USD 13).  You may have to ask the pharmacy to order it for you, it is not widely stocked, or order it online.

A 1 mg tablet of Clemastine contains 1.34 mg of Clemastine hydrogen fumarate.  This can be confusing because one product is marked 1mg and the identical tablet is elsewhere marked 1.34mg.

The US product by Teva is Clemastine 2mg containing 2.7 mg of Clemastine hydrogen fumarate

The experimental dose in Multiple Sclerosis is so high it causes drowsiness.  Clemastine affects histamine H1 receptors in the brain and so makes you sleepy.

My “autism dose” is less than the hay fever dose and is 1mg Clemastine (containing 1.34 mg of Clemastine hydrogen fumarate) taken in the evening.

Some readers are giving a morning dose and an evening dose, as you would for hay fever.  I would expect this to have a greater effect on oligodendrocytes, but will come at the cost of a degree of drowsiness, which may or may not be important.

I think people should be given clemastine immediately after a regression into autism and also anyone suffering as result of hypoxia. We saw the MRI of a man treated with clemastine after hypoxia in an earlier post and we saw the myelin damage and its repair.

Given 18 months of age is the typical age for the first regression in autism, perhaps pediatricians should take note? Perhaps the Johns Hopkins doctors should try using it on their patients with mitochondrial disorders?

I would also think those with what was called CDD (childhood disintegrative disorder) would be likely beneficiaries.

Comments so far suggest that clemastine benefits some people more than others, but this is exactly what you would expect.  In the case of the man with hypoxia, clemastine really was a silver bullet, it was given very promptly and loss of myelin was his only problem.  Most people with severe autism have more problems than just patchy myelin.

Treatment Window

In some single gene autism there does appear to be a treatment window and this has been confirmed in animal models. One example is the very expensive use of the drug Rapamycin in TSC (tuberous sclerosis complex).

Multiple Critical Periods for Rapamycin Treatment to Correct Structural Defects in Tsc-1-Suppressed Brain


Many interventions however do seem to be beneficial regardless of age.

This can be summed up as “it's never too late, but the sooner you start the better the result will be”.

Will a toddler with Pitt Hopkins learn to walk much earlier if taking Clemastine?  The logic is there to support this.

Will a girl with Rett Syndrome regress less far if taking Clemastine, during the regression?

Conclusion

Most parents naturally hesitate to give drugs to treat children with autism. They do not hesitate to give numerous drugs to their elderly relatives, who are the ones who are most likely to get side effects and have much less time to benefit from them.

Some drugs are much safer than others and the irony is that the drugs commonly used to treat autism by psychiatrists are the ones with known problems.

It appears that many very safe existing drugs can be used to treat features of autism.

Do you wait a decade, or likely more, to see if a safe old hay fever drug might improve cognition and/or motor skills in your case of autism or Pitt Hopkins? Or just buy these hay fever pills and see for yourself?

7 Previous posts on/including Clemastine:- 

        https://epiphanyasd.blogspot.com/search/label/Clemastine