Low dose Clonazepam for MIA Autism, Ponstan and TRPM3 in Intellectual Disability, Clemastine to restore myelination in Pitt Hopkins, Improving Oxytocin therapy with Maca, Lamotrigine for some autism

 

Monty in Ginza, Tokyo

Today’s post comes from Tokyo and looks at 5 therapies already discussed in previous posts and follows up on recent coverage in the research. They all came up in recent conversations I have been having.

·      Low dose Clonazepam  – Maternal Immune Activation model of autism

·      Ponstan – TRPM3 causing intellectual disability  (ID/MR)

·      Clemastine – improving myelination in Pitt Hopkins syndrome model

·      Oxytocin – Maca supplement to boost effect

·      Lamotrigine (an anti-epilepsy drug) to moderate autism

The good news is that many of same therapies keep coming up.

Ponstan and TRPM3 caused ID/MR

There is a lot in this blog about improving cognition, which is how I called treating ID/MR.  There are very many causes of ID and some of them are treatable.

ID/MR was always a part of classic autism and in the new jargon is part of what they want to call profound autism.

I was recently sent a paper showing how the cheap pain reliever Ponstan blocks the TRMP3 channel and that this channel when mutated can lead to intellectual disability and epilepsy.

Mefenamic acid selectively inhibits TRPM3-mediated calcium entry.

My own research has established that mefenamic acid seems to improve speech and cognition, as well as sound sensitivity.  The latter effect I am putting down to its effect on potassium channels. 

De novo substitutions of TRPM3 cause intellectual disability and epilepsy

The developmental and epileptic encephalopathies (DEE) are a heterogeneous group of chronic encephalopathies frequently associated with rare de novo nonsynonymous coding variants in neuronally expressed genes. Here, we describe eight probands with a DEE phenotype comprising intellectual disability, epilepsy, and hypotonia. Exome trio analysis showed de novo variants in TRPM3, encoding a brain-expressed transient receptor potential channel, in each. Seven probands were identically heterozygous for a recurrent substitution, p.(Val837Met), in TRPM3’s S4–S5 linker region, a conserved domain proposed to undergo conformational change during gated channel opening. The eighth individual was heterozygous for a proline substitution, p.(Pro937Gln), at the boundary between TRPM3’s flexible pore-forming loop and an adjacent alpha-helix. General-population truncating variants and microdeletions occur throughout TRPM3, suggesting a pathomechanism other than simple haploinsufficiency. We conclude that de novo variants in TRPM3 are a cause of intellectual disability and epilepsy.

 

Fenamates as TRP channel blockers: mefenamic acid selectively blocks TRPM3

This study reveals that mefenamic acid selectively inhibits TRPM3-mediated calcium entry. This selectivity was further confirmed using insulin-secreting cells. K_ATP channel-dependent increases in cytosolic Ca²⁺ and insulin secretion were not blocked by mefenamic acid, but the selective stimulation of TRPM3-dependent Ca²⁺ entry and insulin secretion induced by pregnenolone sulphate were inhibited. However, the physiological regulator of TRPM3 in insulin-secreting cells remains to be elucidated, as well as the conditions under which the inhibition of TRPM3 can impair pancreatic β-cell function. Our results strongly suggest mefenamic acid is the most selective fenamate to interfere with TRPM3 function. 

Here, we examined the inhibitory effect of several available fenamates (DCDPC, flufenamic acid, mefenamic acid, meclofenamic acid, niflumic acid, S645648, tolfenamic acid) on the TRPM3 and TRPV4 channels using fluorescence-based FLIPR Ca²⁺ measurements. To further substantiate the selectivity, we tested the potencies of these fenamates on two other TRP channels from different subfamilies, TRPC6 and TRPM2. In addition, single-cell Ca²⁺ imaging, whole-cell voltage clamp and insulin secretion experiments revealed mefenamic acid as a selective blocker of TRPM3.

  

Oxytocin

 Oxytocin does increase how emotional you feel; the difficulty is how to administer it in a way that provides a long lasting effect.  The half-life of oxytocin is a just minutes. The traditional method uses a nose spray.

I favour the use of a gut bacteria that stimulates the release of oxytocin in the brain.  The effect should be much longer lasting. Even then the effect is more cute than dramatic.

The supplement Maca does not itself produce oxytocin, but “it restores social recognition impairments by augmenting the oxytocinergic neuronal pathways”.

So Maca looks like an interesting potential add-on therapy to boost the effect of oxytocin.

One reader wrote to me with a positive report on using Maca by itself, without any oxytocin.

 

Oral Supplementation with Maca Improves Social Recognition Deficits in the Valproic Acid Animal Model of Autism Spectrum Disorder

Autism spectrum disorder (ASD) is a congenital, lifelong neurodevelopmental disorder whose main symptom is impaired social communication and interaction. However, no drug can treat social deficits in patients with ASD, and treatments to alleviate social behavioral deficits are sorely needed. Here, we examined the effect of oral supplementation of maca (Lepidium meyenii) on social deficits of in utero-exposed valproic acid (VPA) mice, widely used as an ASD model. Although maca is widely consumed as a fertility enhancer and aphrodisiac, it possesses multiple beneficial activities. Additionally, it benefits learning and memory in experimental animal models. Therefore, the effect of maca supplementation on the social behavioral deficit of VPA mice was assessed using a social interaction test, a three-stage open field test, and a five-trial social memory test. The oral supplementation of maca attenuated social interaction behavior deficit and social memory impairment. The number of c-Fos-positive cells and the percentage of c-Fos-positive oxytocin neurons increased in supraoptic and paraventricular neurons of maca-treated VPA mice. These results reveal for the first time that maca is beneficial to social memory and that it restores social recognition impairments by augmenting the oxytocinergic neuronal pathways, which play an essential role in diverse social behaviors.

Maca (Lepidium meyenii) belongs to the cruciferous family and grows at high altitudes in Peru. In 2002, it was transplanted from Peru to the Yunnan Province of China. It is rich in dietary fiber; has many essential amino acids and nutrients including vitamin C, copper, and iron; and its root contains bioactive compounds. It is globally consumed and is popularly used as a fertility enhancer and aphrodisiac. On the other hand, with its potential to possess multi-nutritious components, it is reported to have diverse functions, including immunomodulation, antioxidant, antidepressant, antirheumatic, UV radiation protection, hepatoprotective, anti-fatigue, and neuroprotective effects. Interestingly, although the mechanism of the neuronal effect of maca is unclear, the uptake of maca extract improves learning and memory in memory-impaired model mice induced by either ethanol, ovariectomy, or scopolamine. However, the effects of maca on social memory impairment in neurodevelopmental disorders, including ASD, have not yet been tested.

In this study, the effects of maca on ASD animal models, in utero VPA-exposed mice, were investigated. The effect on social recognition by maca uptake with gavage was assessed using the social interaction test, a three-stage open field test, and the five-trail social recognition test. We also explored whether maca intake affects oxytocinergic signaling pathways, which play an important role in various social behaviors.

In this study, we showed that maca uptake rescues the deficits of social behavior and social recognition memory in VPA mice, a mouse model of autism. The c-Fos immunoreactivity of oxytocinergic neurons in SON and PVN increased significantly after maca treatment in VPA mice. Following previous studies indicating that OT administration ameliorates the impairment of social behavior in VPA mice, maca may also have improving effects on the deficit of social behavior and social recognition memory of VPA mice, probably by activating the OT neuronal pathway. Previous studies showed that maca could improve cognitive function in the mice model of impaired cognitive memory induced by either ovariectomy, ethanol, or scopolamine. Further studies are necessary to elucidate the potential link between maca and OT and to determine which components are involved in improving social recognition memory.

We have shown that maca improves the impairment of social memory and social behavioral deficits through oxytocinergic system modulation in this study. Although maca may not have an immediate effect on social behavioral deficits and takes days or weeks to demonstrate the effects, behavioral improvements, were visible regardless of the time of oral intake. The time between the very last oral intake of maca and the start of the social behavioral experiments in this study was more than 16 h. The duration of the maca’s effect on social behavioral deficits after the supplementation period is being investigated in our follow-up experiments. The possibility of the persistent effect of maca is very appealing, given that OT does not have a sustained effect due to its rapid metabolism, despite its immediate effects. Therefore, taking maca as a supplement while also receiving repeated OT treatment may have a synergistic, sustainable effect on improving social impairment in patients with ASD. Maca is already being used as a dietary supplement worldwide and has a high potential for practical applications.

 

This study showed for the first time that maca supplementation improves the impairment of social recognition memory in ASD model mice. We added the mechanism that social memory improvement may occur through the upregulation of oxytocinergic pathways. Maca highlights the possibility of treating social deficits sustainably in individuals with ASDs.

 

Low dose clonazepam

Professor Catterall was the brains behind low dose clonazepam for mice, I just translated it across to humans. It is one way to modify the E/I (excitatory/inhibitory) imbalance in autism.

I found that it gave a boost to cognition. Not as big as bumetanide, but worth having nonetheless.

I do not believe you have to be a bumetanide responder to respond well to low dose clonazepam.

Several people have written to me recently to say it works for their child.

Our reader Tanya is interested in the Maternal Immune Activation (MIA) trigger to autism. She highlighted a recent study showing how and why clonazepam can reverse autism in the MIA mouse model of autism. 

Clonazepam attenuates neurobehavioral abnormalities in offspring exposed to maternal immune activation by enhancing GABAergic neurotransmission

Ample evidence indicates that maternal immune activation (MIA) during gestation is linked to an increased risk for neurodevelopmental and psychiatric disorders, such as autism spectrum disorder (ASD), anxiety and depression, in offspring. However, the underlying mechanism for such a link remains largely elusive. Here, we performed RNA sequencing (RNA-seq) to examine the transcriptional profiles changes in mice in response to MIA and identified that the expression of Scn1a gene, encoding the pore-forming α-subunit of the brain voltage-gated sodium channel type-1 (Na_V1.1) primarily in fast-spiking inhibitory interneurons, was significantly decreased in the medial prefrontal cortex (mPFC) of juvenile offspring after MIA. Moreover, diminished excitatory drive onto interneurons causes reduction of spontaneous gamma-aminobutyric acid (GABA)ergic neurotransmission in the mPFC of MIA offspring, leading to hyperactivity in this brain region. Remarkably, treatment with low-dose benzodiazepines clonazepam, an agonist of GABA_A receptors, completely prevented the behavioral abnormalities, including stereotypies, social deficits, anxiety- and depression-like behavior, via increasing inhibitory neurotransmission as well as decreasing neural activity in the mPFC of MIA offspring. Our results demonstrate that decreased expression of Na_V1.1 in the mPFC leads to abnormalities in maternal inflammation-related behaviors and provides a potential therapeutic strategy for the abnormal behavioral phenotypes observed in the offspring exposed to MIA.

 

Pitt Hopkins – Clemastine and Sobetirome

Poor myelination is a feature of much autism and is a known problem in Pitt Hopkins syndrome.

I did cover a paper a while back where the Pitt Hopkins researchers showed that genes involved in myelination are down-regulated not only in Pitt Hopkins, but in several other popular models of autism.

From the multiple sclerosis (MS) research we have assembled a long list of therapies to improve different processes involved in myelination. Today we can add to that list sobetirome (and the related Sob-AM2). Sobetirome shares some of its effects with thyroid hormone (TH), it is a thyroid hormone receptor isoform beta-1 (THRβ-1) liver-selective analog.

Some people do use thyroid hormones to treat autism, and indeed US psychiatrists have long used T3 to treat depression.

The problem with giving T3 or T4 hormones is that it has body-wide effects and if you give too much the thyroid gland will just produce less.

One proposed mechanism I wrote about long ago is central hypothyroidism, that is a lack of the active T3 hormone just within the brain. One possible cause proposed was that oxidative stress reduces the enzyme D2 that is used to convert circulating prohormone T4 to T3. The result is that your blood test says your thyoid function is great, but in your brain you lack T3.

It looks like using sobetirome you can spice up myelination in the brain, without causing any negative effects to your thyroid gland.

Rather surprisingly, sobetirome is already sold as a supplement, but it is not cheap like Clemastine, the other drug used in the successful study below.

 

Promyelinating drugs promote functional recovery in an autism spectrum disorder mouse model of Pitt–Hopkins syndrome

Pitt–Hopkins syndrome is an autism spectrum disorder caused by autosomal dominant mutations in the human transcription factor 4 gene (TCF4). One pathobiological process caused by murine Tcf4 mutation is a cell autonomous reduction in oligodendrocytes and myelination. In this study, we show that the promyelinating compounds, clemastine, sobetirome and Sob-AM2 are effective at restoring myelination defects in a Pitt–Hopkins syndrome mouse model. In vitro, clemastine treatment reduced excess oligodendrocyte precursor cells and normalized oligodendrocyte density. In vivo, 2-week intraperitoneal administration of clemastine also normalized oligodendrocyte precursor cell and oligodendrocyte density in the cortex of Tcf4 mutant mice and appeared to increase the number of axons undergoing myelination, as EM imaging of the corpus callosum showed a significant increase in the proportion of uncompacted myelin and an overall reduction in the g-ratio. Importantly, this treatment paradigm resulted in functional rescue by improving electrophysiology and behaviour. To confirm behavioural rescue was achieved via enhancing myelination, we show that treatment with the thyroid hormone receptor agonist sobetirome or its brain penetrating prodrug Sob-AM2, was also effective at normalizing oligodendrocyte precursor cell and oligodendrocyte densities and behaviour in the Pitt–Hopkins syndrome mouse model. Together, these results provide preclinical evidence that promyelinating therapies may be beneficial in Pitt–Hopkins syndrome and potentially other neurodevelopmental disorders characterized by dysmyelination.

 

Sobetirome  (also called GC-1)

Sobetirome is a thyroid hormone receptor isoform beta-1 (THRβ-1) liver-selective analog.

In humans, sobetirome lowers plasma LDL cholesterol and reduced plasma triglycerides, while its liver-selective activity helped avoid the side effects seen with many other thyromimetic agents.

 

Myelin repair stimulated by CNS-selective thyroid hormone action

Oligodendrocyte processes wrap axons to form neuroprotective myelin sheaths, and damage to myelin in disorders, such as multiple sclerosis (MS), leads to neurodegeneration and disability. There are currently no approved treatments for MS that stimulate myelin repair. During development, thyroid hormone (TH) promotes myelination through enhancing oligodendrocyte differentiation; however, TH itself is unsuitable as a remyelination therapy due to adverse systemic effects. This problem is overcome with selective TH agonists, sobetirome and a CNS-selective prodrug of sobetirome called Sob-AM2. We show here that TH and sobetirome stimulated remyelination in standard gliotoxin models of demyelination. We then utilized a genetic mouse model of demyelination and remyelination, in which we employed motor function tests, histology, and MRI to demonstrate that chronic treatment with sobetirome or Sob-AM2 leads to significant improvement in both clinical signs and remyelination. In contrast, chronic treatment with TH in this model inhibited the endogenous myelin repair and exacerbated disease. These results support the clinical investigation of selective CNS-penetrating TH agonists, but not TH, for myelin repair.

 

Compound protects myelin, nerve fibers

 

Research could be important in treating, preventing progression of multiple sclerosis, other neurodegenerative diseases

A compound appears to protect nerve fibers and the fatty sheath, called myelin, that covers nerve cells in the brain and spinal cord. The new research in a mouse model advances earlier work to develop the compound - known as sobetirome - that has already showed promise in stimulating the repair of myelin.

Lead author Priya Chaudhary, M.D., assistant professor of neurology in the OHSU School of Medicine who is focused on developing therapies for neurodegenerative diseases, said that the technique is a common step in drug discovery.

"It is important to show the effectiveness of potential drugs in a model that is most commonly used for developing new therapies," Chaudhary said.

The researchers discovered that they were able to prevent damage to myelin and nerve fibers from occurring, by stimulating a protective response in the cells that make and maintain myelin. They also reduced the activity of migroglia, a type of inflammatory cell in the brain and spinal cord that's involved in causing damage in multiple sclerosis and other diseases.

"The effects are impressive and are at least in part consistent with a neuroprotective effect with particular inhibition of myelin and axon degeneration, and oligodendrocyte loss," the authors write.

The discovery, if proven in clinical trials involving people, could be especially useful for people who are diagnosed with multiple sclerosis early in the disease's progression.

"The drug could protect the nervous system from damage and reduce the severity of the disease," Bourdette said.

 

Does Lamotrigine have the potential to 'cure' Autism?

Recently headlines appeared like this one:-

Scientists 'CURE autism' in mice using $3 epilepsy drug

It referred to the use of the epilepsy drug Lamotrigine to treat a mouse model of autism, caused by reduced expression of the gene MYT1L.

What the tabloid journalists failed to notice was that there has already been a human trial of Lamotrigine in autism.  That trial was viewed as unsuccessful by the clinicians, although the parents did not agree.

There were many comments in the media from parents whose child already takes this drug for their epilepsy and they saw no reduction in autism. There were some who found it made autism worse.

 

MYT1L haploinsufficiency in human neurons and mice causes autism-associated phenotypes that can be reversed by genetic and pharmacologic intervention

 

Lamotrigine therapy for autistic disorder: a randomized, double-blind, placebo-controlled trial

In autism, glutamate may be increased or its receptors up-regulated as part of an excitotoxic process that damages neural networks and subsequently contributes to behavioral and cognitive deficits seen in the disorder. This was a double-blind, placebo-controlled, parallel group study of lamotrigine, an agent that modulates glutamate release. Twenty-eight children (27 boys) ages 3 to 11 years (M = 5.8) with a primary diagnosis of autistic disorder received either placebo or lamotrigine twice daily. In children on lamotrigine, the drug was titrated upward over 8 weeks to reach a mean maintenance dose of 5.0 mg/kg per day. This dose was then maintained for 4 weeks. Following maintenance evaluations, the drug was tapered down over 2 weeks. The trial ended with a 4-week drug-free period. Outcome measures included improvements in severity and behavioral features of autistic disorder (stereotypies, lethargy, irritability, hyperactivity, emotional reciprocity, sharing pleasures) and improvements in language and communication, socialization, and daily living skills noted after 12 weeks (the end of a 4-week maintenance phase). We did not find any significant differences in improvements between lamotrigine or placebo groups on the Autism Behavior Checklist, the Aberrant Behavior Checklist, the Vineland Adaptive Behavior scales, the PL-ADOS, or the CARS. Parent rating scales showed marked improvements, presumably due to expectations of benefits.

One reader of this blog who heard all about the news and was sceptical, since after all it is a mouse model. Her 8 year old non-verbal child was not happy taking the drug Keppra and was already scheduled to try Lamotrigine. 

“Within a week his teacher called to say he was saying his ABCs, the next week he was counting out loud, the following month he’s attempting to repeat words of interest and this week he’s spelling animals by memory, dolphin, duck, wolf, chicken, pig, etc.

We are 2 months in and at 50mg, our target dose is 100mg bid. Obviously with our success, I’ve been working with his doctor and will continue to.”

 

Conclusion

Even though every day new autism research is published, there is so much already in this blog that not much appearing is totally new to regular readers.

We saw several years ago that low dose clonazepam should be beneficial to some people with autism, in particular Dravet syndrome. Today we learnt a little more about why Nav1.1 might be disturbed beyond those with Dravet syndrome. In the maternal immune activation model it seems to be a winner. It seems to benefit many of those who have trialed it.

Treating myelination deficits has been well covered in this blog. In previous posts we saw how Pitt Hopkins syndrome researchers showed how myelination gene expression was disturbed in a wide range of autisms. Today we saw evidence to support such therapy and we discovered a new drug.

Oxytocin does help some people with autism, but not as much as you might expect. Today we learnt of a potential add on therapy, a supplement called Maca.

The idea that anti-epilepsy drugs might help some autism has been well covered. From low dose valproate to low dose phenytoin from Dr Philip Bird in Australia.

Treatment of Autism with low-dose Phenytoin, yet another AED

Recent research suggested that Lamotrigine should help some with autism and today you learned that it really does help in one case. The fact that a tiny study a few years ago suggested no responders just tells us that only a small subgroup are likely to benefit.

We already know that some people's autism is made worse by their epilepsy therapy. This is just what you would expect. Time to find a different epilepsy therapy.

My favorite new therapy, low dose mefenemic acid / ponstan has numerous effects. One reader without autism, but with an unusual visual dysfunction (visual snow syndrome) and a sound sensitivity problem contacted me a while to see if NKCC1 might be the root of his problem. I suggested he try Ponstan, which did actually work for him and is easy to buy where he lives. Now he sends me research into all its possible modes of action. One mode of action relates to a cause of intellectual disability (ID/MR). Is this a factor in why Ponstan seems to improve speech and cognition in some autism? I really don't mind why it works - I just got lucky again, that is how I look at it. The more I read the luckier I seem to get.

Suramin - Why do Clinical Trials in Autism Struggle to be Convincing? And Oxytocin fails in a large trial.

 

Results from the PaxMedica trial of Suramin

For me, Bumetanide for Autism is now ten-year-old news, for us it has been working since 2012; the next interesting drugs in the pipeline include Suramin and Leucovorin.

It is extremely difficult to trial Suramin at home, or indeed anywhere, and this makes it ever more desirable to many parents.

Leucovorin (calcium folinate) is easy to obtain; you can even buy liquid calcium folinate from iHerb.  You can find out pretty quickly if it produces a profound benefit on your child’s type of autism.

I wish Dr Frye and Professor Ramaekers good luck with the phase 3 trial of Leucovorin.  It certainly works for our adult reader Roger, but not for my 18 year old son, Monty.  Our reader SB’s child recently joined the group of confirmed responders.

After I started writing this post, the results came in of a large (250 children) trial of intranasal oxytocin.  This trial failed to show any benefit, over the placebo, in increasing social behaviors in autistic children. As I have mentioned previously, there is an inherent problem with intranasal oxytocin, the hormone has a very short action, its half-life is 2-6 minutes. It would be much more effective to provide a sustained release of oxytocin, which can indeed be achieved via adding a specific bacterium to the gut. The other problem with intranasal delivery is that you are not supposed to inhale the drug into your lungs, it has to stay in upper part of your nose. How likely is it that parents/children use the spray correctly?  There is even a special dispenser developed for drug delivery to the brain, but did they use it?

In my trials of L. reuteri DSM 17938 it was obvious that the oxytocin improved social behaviors, but I concluded that this was not such a big deal and certainly was not a treatment priority. How would you assess the effect? Very simple, you just count how many times your child is shaking boys’ hands and kissing the girls. I don’t suppose that was the measurement that Duke University used.

Many parents do use Syntocinon nasal spray and this failed trial does not mean they are imagining the effects.  If I was them, I would try L. reuteri DSM 17938 and compare the effect and use whichever is the most beneficial.

  

Suramin 

Suramin is moving towards its Phase 3 clinical trials and, very unusually, two different companies are trying to commercialize the same drug.  One company is PaxMedica and the other is Kuzani, who are ones that cooperate with Dr Naviaux.

In the background is Bayer, the German giant, who have been making Suramin for a hundred years as a therapy for African sleeping sickness and river blindness.  We are told that making Suramin is quite difficult, it is a large molecule; but if they could make it a century ago, how difficult can it really be?  The reality appears to be that Bayer do not want to supply PaxMedica or Kuzani and so they will have to figure out how to make it.  Suramin is sold as a research chemical, but there seem to be questions about its purity. The very cheap Suramin sold on the internet is very likely to be fake.

Today we will look at the data from the South African trial carried out by PaxMedica and take a look at their patent for their intranasal formulation.

We have heard very positive anecdotal reports from the very small initial trials carried out by Professor Naviaux.  Naviaux himself is very interesting, because even though he is not an autism researcher, he is far more knowledgeable than almost all of them on the subject of autism. If you read his papers, they show a rare global understanding of the subject.  This “big picture” is what you need to understand such a heterogenous condition as autism.

In the PaxMedica trial, 44 children completed the trial, so that should be enough to tell us something insightful about whether this drug is effective.

A recurring problem in all autism trials is how well the placebo performs.  Here again in the Paxmedica data we have a very impressive blue line – the placebo.  It is just salt and water and yet it is nearly as good as the trial drug (the orange line).

 

A big part of clinical trials is the statistics used to validate them.

Although I do have a mathematical background, I believe in “seeing is believing”.  The data should be crying out to you what it means.  If it is so nuanced that it needs a statistician to prove the effect, there likely is no effect.

In the above chart we want to see a decreasing slope that would possibly level off as the drug achieved its maximum effect.

What we see are two apparently effective therapies, blue and orange. 

The problem is that blue line is just water, with a bit of salt.

 

Show me the data

What we really want to see are results of each of the 44 participants, not the average.

There are likely groups:

·        Super responders

·        Responders

·        Partial responders

·        Non-responders

 

No statistician is needed.

 

The data from the Suramin trial needs to be presented in the kind of form used in the stem cell trial below:-

Since many hundreds of different biological conditions can lead to an autism diagnosis, we really should not expect there to be any unifying therapy that works for everyone.  Indeed, we should perhaps be suspicious of any therapy claimed to work for everyone.

We always get to hear about the super-responders in anecdotal reports.

We heard great things about Memantine/Namenda, but the phase 3 trial was a failure.  We heard great things about Arbaclofen (R-Baclofen), but the phase 3 trial failed. In Romania our reader Dragos is currently seeing great benefits from the standard version of Baclofen (a mixture of R-Baclofen and S-Baclofen).

My son is a super-responder to Bumetanide, but I know that most people are not. However, when I came across the “bumetanide has stopped” working phenomena, it became clear that the situation is more complex than a single one-time evaluation. We know why bumetanide can “stop working” and how to make it “start working again”.  An increase in inflammatory cytokines from the periphery (i.e. outside the brain) further increases the expression of NKCC1 in the brain and negates the effect of bumetanide; reduce the inflammation and bumetanide will start to work again.

  

Why does the placebo always do well in autism trials?

The assessments used to measure outcome are all observational, they are not blood tests or MRI scans.  They are highly subjective.

It has been suggested that just being in an autism trial improves symptoms of autism.  The parents give more attention to the child and this then skews the results.

My way round this problem in my n=1 trials was always to tell nobody about the new trial I was making and wait for unprompted feedback.  This works really well.

 

 

Who chooses the trial goal (the primary endpoint)?

I like the fact that in the Leucovorin trial the goal is speech.  It is a very simple target and relatively easy to measure.

For Bumetanide, I did suggest to the researchers that they used change in IQ as an endpoint.  Nice and simple, start with kids with IQ<70 and then recruit those who have a negative reaction (paradoxical response) to Valium/diazepam.  Then expect an increase in measured IQ of 10 to 40 points.  Then you would have a successful phase 3 trial.    

In many previous trials that ultimately failed, some people did see a benefit, but they were different benefits.  I did get a reader telling me how great Memantine (Namenda) had been for her child, when I asked why she told me that it was the only therapy that had ever solved her child GI problems.  That certainly was never considered as a trial goal/endpoint.

In my trial of Pioglitazone, I read the research about both the mechanism of action and the observed effects listed in the phase 2 trial:

"improvement was observed in social withdrawal, repetitive behaviors, and externalizing behaviors as measured by the Aberrant Behavior Checklist (ABC), Child Yale-Brown Obsessive Compulsive Scale (CY-BOCS), and Repetitive Behavior Scale–Revised (RBS-R)."

I was targeting something entirely different.  Based on the mechanism of action, specifically the reduction of the inflammatory cytokine IL-6, I expected a reduction in summertime raging.  It worked exactly as hoped for. This is the second summer we have used it.

Our reader Sara’s initial assessment of the effect of Pioglitazone is focused on the improvement in sleeping patterns.  This is great, assuming the benefit is maintained, but it is an entirely different benefit.

 

Was the trial drug actually taken?

I suspect in the bumetanide trial, many parents did not give the trial drug every day, as per their instructions, because the diuresis was too much bother.  I know from reader comments and emails that many parents stop giving bumetanide, even though their child is a responder.  Some schools refuse to allow bumetanide because of the disruption caused by frequent toilet breaks.

Because Suramin is given once a month by infusion, there is 100% certainty that the drug or placebo was actually taken.  This is a big plus.

Was the intranasal oxytocin correctly administered in the recent trial? I doubt it.

The problem with Leucovorin is that in a minority of children is causes aggression, even if you follow Prof Ramaeker’s advice and very slowly increase the dosage.  In the phase 3 trial parents should be informed of this possibility and told to report it and be invited to withdraw from the trial.  If they just stop the therapy to halt the aggression, but their data remains included in the study, the results are invalidated.

 

Intranasal Suramin

Patents are often a good source of information and they do also tell you something about the people who wrote them.

Here below is PaxMedica's patent for intranasal suramin:-

Compositions and methods for treating central nervous system disorders

These results demonstrate that an antipurinergic agent such as suramin can be delivered intranasally to achieve plasma and brain tissue levels and that variations in the brain tissue to plasma partitioning ratio can be observed. These results demonstrate that an antipurinergic agent such as suramin can be delivered to the brain of a mammal by intranasal (IN) administration. 

The following Table 1 provides the averaged accumulated amount, in mg, of suramin that has penetrated as a function of time

But how can the accumulated level after 6 hours be less than after 5 hours?

The results of the study are also shown graphically in FIG. 1 where the cumulative amount (mg) of drug permeated was plotted versus time in hours. These data demonstrate that Formulation B containing methyl β-cyclodextrin (methyl betadex) provides significantly better penetration, versus Formulations, A , C, and D in the tissue permeation assay. Also, as is seen from a comparison of Formulations A and D, having a higher drug concentration can be advantageous to increasing permeation.

 

Formulation A - suramin hexa-sodium salt at 100 mg/mL in water (no excipients) Formulation B - suramin hexa-sodium salt at 100 mg/mL in water, with 40% methyl β-cyclodextrin (methyl betadex) Formulation C - suramin hexa-sodium salt at 100 mg/mL in water, with 40% HP (hydroxyl propyl) -cyclodextrin Formulation D - suramin hexa-sodium salt at 160 mg/mL in water (no excipients)

 

FIG. 7 shows a plot comparing the total percentage of suramin in plasma in mice when administered by intraperitoneal (IP) injection once weekly for 4 weeks (28 days), intranasally (IN) daily for 28 days, intranasally (IN) every other day for 28 days, and intranasally (IN) once per week for 4 weeks (28 days).

 

FIG. 8 shows a plot comparing the total percentage of suramin in brain tissue in mice when administered by intraperitoneal (IP) injection once weekly for 4 weeks (28 days), intranasally (IN) daily for 28 days, intranasally (IN) every other day for 28 days, and intranasally (IN) once per week for 4 weeks (28 days).

 

Does anyone think the above chart makes any sense? 

 

The mice were maintained in group cages (6 mice per cage based on treatment group) in a controlled environment (temperature: 2 1.5 ± 4.5 °C and relative humidity: 35-55%) under a standard 12-hour light/1 2-hour dark lighting cycle (lights on at 06:00). Mice were accommodated to the research facility for approximately a week. Body weights of all mice were recorded for health monitoring purposes.

The mice were divided into the following 5 test groups, with 6 mice per group.

Group 1: Intraperitoneal (IP) injection of suramin, 20 mg/kg, administered weekly to animals beginning at 9 weeks of age and continuing for four weeks (i.e. given at Age Weeks 9 , 10 , 11 and 12). The suramin was formulated in Normal saline solution.

Group 2 : Intraperitoneal (IP) injection of saline, 5 mL/g, administered weekly to animals beginning at 9 weeks of age and continuing for four weeks (i.e. given at Age Weeks 9 , 10 , 11 and 12). This was a control group.

Group 3 : Intranasal (IN) administration of a formulation, described below, of suramin, at a concentration of 100 mg/mL x 6 mL per spray, administered as one spray per nostril, one time per day, (interval of each application is around 2 minutes to ensure absorption) for 28 days (total of 56 sprays over 28 day period) beginning at 9 weeks of age (i.e. given daily during Age Weeks 9 , 10 , 11 and 12).

Group 4 : Intranasal (IN) administration of a formulation, described below, of suramin, at a concentration of 100 mg/mL x 6 mL per spray, administered as one spray per nostril, one time every other day, for 28 days (total of 28 sprays over 28 day period) beginning at 9 weeks of age (i.e. given once every other day during Age Weeks 9 , 10, 11 and 12).

Group 5 : Intranasal (IN) administration of a formulation, described below, of suramin, at a concentration of 100 mg/mL x 6 ml_ per spray, administered as one spray per nostril, one time every week, for 4 weeks (28 days) (total of 8 sprays over 28 day period) beginning at 9 weeks of age (i.e. given once weekly during Age Weeks 9 , 10 , 11 and 12).

 

This question was posed to me:-

A nasal spray in a human is about 0.1 ml, how do you give a tiny mouse 6 ml per nostril?  Even 0.6 ml looks implausible.

 

Conclusion

Will Suramin pass a phase 3 trial?  I think if it is trialed on a random group of 400 young people with moderate or severe autism, it will very likely fail.

Professor Naviaux believes Suramin may be a unifying therapy, one that works in all autism.  The results from the PaxMedica study do not support this.

PaxMedica has the data showing the individual results.  Are there super-responders? Are there non-responders? Does Suramin perhaps make some people's autism worse?  All we can see is the average response, which is marginally better than the placebo; not what we expected after seeing the initial study.

Expecting Suramin to work well for everyone is raising the bar too high.  Try and identify markers for the responders and super-responders and then limit the phase 3 trial to these people.

Is intranasal delivery of Suramin going to achieve a therapeutic level inside the human brain?  Hopefully yes, but it may not work.

Is long term use of Suramin going to be safe? Will it require ever-increasing doses? Nobody knows, and note that safety was the original concern when Suramin’s use was proposed by Naviaux.

Intranasal administration has the best chance of being totally safe.  Spend a little extra money on the clever dispenser covered in this old post, that keeps 100% of the drug in the right place.

 

https://epiphanyasd.blogspot.com/2015/09/opn-300-oxytocin-and-autism.html

 

Maybe get someone other than a lawyer, to proof read your patent.

 

 

Vasopressin, Oxytocin, the Lateral Septum, Aggression and Social Bonding, Autism gene NLGN3 and MNK inhibitors for reversing Fragile-X and likely more Autism

 

The Lateral Septum, in green, turns the volume

 up or down in aggression

Today’s post started by me checking for anything new in the research about the hormone Vasopressin and autism. I was surprised by just how much research continues to be published on the subject – no smoke without fire, perhaps.

We also get another insight into how aggressive raging develops in the brain; we even have a photo.

A novel therapy for Fragile-X is also thrown into the mix, due to a link to oxytocin.

So, what is cooking in the research?

The first thing to note is that you really do have to look at both Oxytocin and Vasopressin, because these two hormones are very closely related.

We have previously looked at the autism gene NLGN3, this gene encodes the cute sounding neuroligin-3.

 

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

 

The reason people with Fragile-X have autism is because they lack the protein FMRP (Fragile X mental retardation protein).

In healthy neurons, FMRP modulates the local translation of numerous synaptic proteins. Synthesis of these proteins is required for the maintenance and regulation of long-lasting changes in synaptic strength. In this role as a translational inhibitor, FMRP exerts profound effects on synaptic plasticity.

When you look at the interactions of the FMRP protein you can find ways to compensate for this deficiency.  This is nicely illustrated in the graphic below. You just need to find another way to influence elF4E and elF4G.

Some people have told me they find these charts a bit overwhelming, but they precisely show what is going on.  You just have to look up all the terms, you do not know.  In the chart below there is NF1 autism, there is PTEN autism, problems with Ras are called RASopathies and cause MR/ID plus autism. We have at least one reader with TSC (Tuberous sclerosis) type autism. We have readers whose kids lack FMRP, because they have Fragile-X syndrome. 

Today we see that an inhibitor of MnK (in yellow in the chart below) is another via option to treat Fragile-X.

Beyond Fragile-X, we can see that numerous other upstream dysfunctions in the chart can result in miss-expression of neuroligins (NLGNs) in the chart below and then result in autism.

 

 One of the papers below goes further and suggests

“This work uncovers an unexpected convergence between the genetic autism risk factor Nlgn3, translational regulation, oxytocinergic signalling, and social novelty responses”

“We propose that pharmacological inhibition of MNKs may provide a new therapeutic strategy for neurodevelopmental conditions with altered translation homeostasis”

“Our work not only highlights a new class of highly-specific, brain-penetrant MNK inhibitors but also expands their application from fragile X syndrome to a non-syndromic model of ASD”

 

Regarding Fragile X 

“Collectively, this work establishes eFT508 (an MNK inhibitor) as a potential means to reverse deficits associated with FXS.”

 

What is the connection to Oxytocin?

A problem with your neuroligins causes an impairment in oxytocin signalling.

 

The role of the Lateral Septum (LS) in both aggression and desirable social behavior 

If you scan through the research on vasopressin and oxytocin you will eventually come across references to the LS.  The LS is a part of your brain called the Lateral Septum.

In the picture below you see a mouse brain and the green part is the Lateral Septum (LS).

 

Source: https://neurosciencenews.com/rage-lateral-septum-3637/ 

“Our research provides what we believe is the first evidence that the lateral septum directly ‘turns the volume up or down’ in aggression in male mice, and it establishes the first ties between this region and the other key brain regions involved in violent behavior”

Both social bonding and offensive aggression involve vasopressin receptors in a part of the brain called the Lateral Septum (LS).  Activity in the Lateral Septum (LS) is regulated by inhibitory GABA, and excitatory glutamate.

There is a notable difference between males and females, at least in rats.  No sex differences were found in extracellular GABA concentrations during social playing; however, glutamate plays a major role in female social playing. When glutamate receptors are blocked in the LS pharmacologically, there is a significant decrease in female social playing, while males had no decrease in playing. This suggests that in the lateral septum, GABA neurotransmission is involved in social play behavior regulation in both sexes, while glutamate neurotransmission is sex-specific, involved in regulation of social play only in females.

 

Aggressive behavior in females 

Neural mechanisms of female aggression: Implications on the oxytocin and vasopressin systems

These models allowed me to investigate the role of the brain oxytocin (OXT) and vasopressin (AVP) systems on aggressive behavior. Both neuropeptides are known to regulate social including aggressive behaviors in males and lactating females.

Taken together this part of my thesis shows that the balance between OXT and AVP release within the LS regulates female aggression in a receptor and region-specific manner via modulating GABAergic neurotransmission.

Overall, this thesis shows that females are able to develop escalated as well as abnormal aggression just like males. In addition, the OXT and the AVP system seem to be main players in regulating aggressive behavior in female Wistar rats, especially, regarding their role in controlling aggression by acting on the LS.

 

The effect of Vasopressin as a therapy

 

Correction of vasopressin deficit in the lateral septum ameliorates social deficits of mouse autism model 

Intellectual and social disabilities are common comorbidities in adolescents and adults with MAGE family member L2 (MAGEL2) gene deficiency characterizing the Prader-Willi and Schaaf-Yang neurodevelopmental syndromes. The cellular and molecular mechanisms underlying the risk for autism in these syndromes are not understood. We asked whether vasopressin functions are altered by MAGEL2 deficiency and whether a treatment with vasopressin could alleviate the disabilities of social behavior. We used Magel2-knockout mice (adult males) combined with optogenetic or pharmacological tools to characterize disease modifications in the vasopressinergic brain system and monitor its impact on neurophysiological and behavioral functions. We found that the activation of vasopressin neurons and projections in the lateral septum were inappropriate for performing a social habituation/discrimination task. Mechanistically, the lack of vasopressin impeded the deactivation of somatostatin neurons in the lateral septum, which predicted social discrimination deficits. Correction of vasopressin septal content by administration or optogenetic stimulation of projecting axons suppressed the activity of somatostatin neurons and ameliorated social behavior. This preclinical study identified vasopressin in the lateral septum as a key factor in the pathophysiology of Magel2-related neurodevelopmental syndromes.

 

In humans, intranasal administration of AVP increased activity in the LS and reciprocated social collaboration (47). Intranasal OXT administration enhances the suppression of oscillatory activity (8–25 Hz) during execution and observation of social actions (48). Altogether, OXT- and AVP-dependent modulation of neural activity in response to social stimuli directly affect EEG activity, which may have a predictive value for the impact of such treatment in ASD-associated disorders. Furthermore, an imbalance between inhibition and excitation is associated with ASD, and AVP treatment could reset the balance by altering the functions of SST neurons (49).

  

Predicting Autism measuring Neonatal CSF vasopressin concentration 

We have yet another predictor of future autism.

Neonatal CSF vasopressin concentration predicts later medical record diagnoses of autism spectrum disorder

The Russian paper below is very thorough. At least in the case of autism, I do not agree with the therapeutic implications.  The paper suggests Oxytocin agonists (like oxytocin itself) and Vasopressin antagonists.

I propose Oxytocin agonists and Vasopressin agonists, as a practical solution today.  It is not a perfect solution, but totally doable today.

  

The role of oxytocin and vasopressin dysfunction in cognitive impairment and mental disorders 

Oxytocin (OXT) and arginine-vasopressin (AVP) are structurally homologous peptide hormones synthesized in the hypothalamus. Nowadays, the role of OXT and AVP in the regulation of social behaviour and emotions is generally known. However, recent researches indicate that peptides also participate in cognitive functioning. This review presents the evidence that the OXT/AVP systems are involved in the formation of social, working, spatial and episodic memory, mediated by such brain structures as the hippocampal CA2 and CA3 regions, amygdala and prefrontal cortex. Some data have demonstrated that the OXT receptor's polymorphisms are associated with impaired memory in humans, and OXT knockout in mice is connected with memory deficit. Additionally, OXT and AVP are involved in mental disorders' progression. Stress-induced imbalance of the OXT/AVP systems leads to an increased risk of various mental disorders, including depression, schizophrenia, and autism. At the same time, cognitive deficits are observed in stress and mental disorders, and perhaps peptide hormones play a part in this. The final part of the review describes possible therapeutic strategies for the use of OXT and AVP for treatment of various mental disorders.

 

4.4. Autism

Autism spectrum disorder (ASD) is a group of disorders that are characterized by early disturbances of social communication and limited, repetitive behaviour. Individuals with autism have impaired social cognition and social perception, executive dysfunction, and atypical perceptual and information processing. Additionally, they exhibit atypical neural development at the systems level . Autism is characterized by a disturbance of social interaction first of all, but it is also characterized by cognitive dysfunctions, including working memory impairment. The OXT/AVP system plays a role in such deficits. In male mice with a mutation in the Magel2 gene, social behaviour and cognitive functions are disrupted in adulthood, which makes this model similar to ASD. The lack of Magel2 causes a change in the OXT system. Subcutaneous administration of OXT to mice with this mutation during the first week of life suffices to restore normal social behaviour and learning abilities in adult mice. Exogenous OXT stimulates the release of endogenous OXT and inhibits the accumulation of intermediate forms of OXT (this is observed in OXT neurons in mice with the Magel2 mutation). This was revealed by neuroimaging methods. Human ASD is associated with altered face processing and decreased activity in brain areas involved in this process. OXT enhances the importance of social stimulus in ASD, and probably can stimulate face processing and eye contact in people with ASD. Genetic polymorphisms of the OXT and AVP receptor genes are associated with ASD. Additionally, this review revealed a link between social cognition disorders in autism and some SNPs in the OXTR and V1a receptor genes. The most significant associations between SNPs in OXTR and social cognition were found for rs2254298, rs53576 and rs7632287. SNP rs2254298 has been associated with a diagnosis of ASD. SNP in the V1a receptor gene, rs7294536, is closely associated with a deficit in social interactions. In addition, OXTR rs237887 polymorphism affects facial recognition memory in families with autistic children.

 

 

 

 

Fig 1. The role of oxytocin and vasopressin systems in the pathogenesis of mental disorders. Stress activates the HPA axis and rises in plasma glucocorticoid levels, which leads to social through the cortisol release. HPA axis activation increases the risk of development of psychopathologies. OXT and AVP regulate emotional behaviours, multiple aspects of social behaviour and cognitive functions. Negative environment, including stress factor, causes an imbalance of the OXT/AVP system, which also leads to psychopathological behaviour: aggression, social impairment, anxiety, emotional and cognitive disorders. At the same time, the OXT/AVP system forms a reaction to stress oppositely. OXT inhibits the HPA axis stress induced activity (anxiolytic effect). AVP activates the HPA axis (anxiogenic effect). OXT and AVP can be used as the treatment of mental diseases associated with social and cognitive dysfunctions. OXT – oxytocin; AVP – arginine-vasopressin; iOXT – intranasal oxytocin; iAVP – intranasal arginine-vasopressin; ACTH - adrenocorticotropic hormone; CRH – corticotropin releasing hormone; HPA axis - hypothalamic-pituitary-adrenal axis.

 

 

5. OXT and AVP systems in mental disorder treatments in recent years, interest in the usage of OXT as the treatment of various psychiatric diseases is growing. OXT and AVP systems that exist in balance produce the contrary effect on emotional behaviour. Positive social stimuli and/or psychopharmacotherapy can shift this balance towards OXT and can help to stimulate emotional behaviour and restore mental health through this shifting. OXT produces an effect on several neurobiological systems, including the HPA axis, limbic system, neurotransmitters, and immune processes related to stress disorders. The exact effects of iOXT still remain unclear; nevertheless, it is known that iOXT action depends on individual sensitivity. Data from functional magnetic resonance imaging demonstrated that iOXT induces temporary activation of some cortex areas and prolonged activation of hippocampus and forebrain areas. These structures are characterized by a high density of OXT receptors. At the same time, iAVP causes stable deactivation in the parietal cortex, thalamus, and mesolimbic pathway. Importantly, the intravenous administration of OXT and AVP does not repeat activation patterns caused by intranasal administration of OXT and AVP. Nevertheless, it is possible that a small amount of OXT which crosses the blood-brain barrier may lead to an additional central OXT release since OXT is able to bind to brain OXT ergic neurons and cause its own release. Generally, OXT doses administered in studies vary from 15 IU to more than 7000 IU. As the table indicates, the results of these studies are very different. The most frequently used dose is 24 IU. Many studies are focused on the capability of OXT in the treatment of depressive disorders. It was demonstrated that iOXT reduces the time of concentration on aggressive facial expressions and increases the time of concentration on happy faces in men and women with chronic depression. Therefore, iOXT regulates emotion recognition in depression. iOXT can be used in combination with antidepressants, enhancing antidepressant efficiency. iOXT administration positively affects mother-child relationship in mothers with postpartum depression (PPD). iOXT activates the protective behaviour of mothers with PPD towards their children. Similar results were found in animal experiments. In rats, iOXT reduced the depressive-like behaviour in adult animals subjected to early maternal separation. Moreover, the research of specific neurogenesis markers Ki67 and BrdU demonstrated that iOXT promotes hippocampal neurogenesis, which is impaired in depressed rats. Many studies investigate the therapeutic properties of iOXT and iAVP for the treatment of schizophrenia and autism. It is known that schizophrenia disturbs social behaviour; and cognitive function. iOXT has the potential for usage as a therapeutic tool to restore impaired functions during schizophrenia. Some data suggest that iOXT reduces the negative symptoms of schizophrenia, improves working memory, verbal memory and cognitive function, and also improves social function in patients with schizophrenia and schizoaffective disorder. Although many studies indicate a positive effect of iOXT on cognitive function in people with schizophrenia, the neuropeptide has a very selective action on behaviour. The exact mechanism of iOXT action is also indefinite; therefore, its therapeutic potential requires further research. Eventually, iOXT can be used as an additional therapeutic agent in traditional schizophrenia treatment. iOXT can also be applied to ASD treatment. It was found that iOXT improves social abilities in children and emotionality in adult men with ASD. Moreover, the improvement of emotional state was observed in adults after an 8 IU dose, but not after 24 IU. The study of iOXT's therapeutic properties was also carried out using a mouse valproate autism model. iOXT improved social behaviour in that model, and reduced anxiety, depressive-like behaviour, and repetitive behaviour. iOXT has some positive effects in the ASD treatment. Despite this, studies of the potential therapeutic usage of iOXT are still at an early stage, and doctors have insufficient data to prescribe iOXT to patients. A few data indicate the therapeutic possibilities of AVP compared to OXT. It is known that iAVP was used in the treatment of the first episode of schizophrenia, in addition to the traditional benzodiazepine treatment. Cognitive functions (namely the memorization process, long-term and short-term memory) improved in patients. iAVP treatment ameliorated social ability in children with ASD. Additionally, iAVP treatment reduced anxiety and repetitive behaviors in these children. These data indicate the necessity of further investigation of AVP's treatment potential.

 

 

Rescue of oxytocin response and social behaviour in a mouse model of autism

A fundamental challenge in developing treatments for autism spectrum disorders is the heterogeneity of the condition. More than one hundred genetic mutations confer high risk for autism, with each individual mutation accounting for only a small fraction of cases^1-3. Subsets of risk genes can be grouped into functionally related pathways, most prominently those involving synaptic proteins, translational regulation, and chromatin modifications. To attempt to minimize this genetic complexity, recent therapeutic strategies have focused on the neuropeptides oxytocin and vasopressin^4-6, which regulate aspects of social behaviour in mammals⁷. However, it is unclear whether genetic risk factors predispose individuals to autism as a result of modifications to oxytocinergic signalling. Here we report that an autism-associated mutation in the synaptic adhesion molecule Nlgn3 results in impaired oxytocin signalling in dopaminergic neurons and in altered behavioural responses to social novelty tests in mice. Notably, loss of Nlgn3 is accompanied by a disruption of translation homeostasis in the ventral tegmental area. Treatment of Nlgn3-knockout mice with a new, highly specific, brain-penetrant inhibitor of MAP kinase-interacting kinases resets the translation of mRNA and restores oxytocin signalling and social novelty responses. Thus, this work identifies a convergence between the genetic autism risk factor Nlgn3, regulation of translation, and oxytocinergic signalling. Focusing on such common core plasticity elements might provide a pragmatic approach to overcoming the heterogeneity of autism. Ultimately, this would enable mechanism-based stratification of patient populations to increase the success of therapeutic interventions. 

Social recognition and communication are crucial elements in the establishment and maintenance of social relationships. Oxytocin and vasopressin are two evolutionarily conserved neuropeptides with important functions in the control of social behaviours, in particular pair-bonding and social recognition7,8 . In humans, genetic variation of the oxytocin receptor (OXTR) gene is linked to individual differences in social behaviour9 . Consequently, signalling modulators and biomarkers for the oxytocin or vasopressin system are being explored for conditions with altered social interactions such as autism spectrum disorders (ASDs)5,6 . In mice, mutation of the genes encoding oxytocin or its receptor results in a loss of social recognition and social reward signalling10–14. Mutation of Cntnap2, a gene linked to ASD in humans, resulted in reduced levels of oxytocin in mice, and the addition of oxytocin improved social behaviour in this model15. However, the vast majority of genetic risk factors for autism have no known links to oxytocinergic signalling. 

Thus, modification of translation homeostasis in Nlgn3KO mice by MNK inhibition restores oxytocin responses and social novelty responses. This work uncovers an unexpected convergence between the genetic autism risk factor Nlgn3, translational regulation, oxytocinergic signalling, and social novelty responses. Although loss of Nlgn3 impairs oxytocin responses in VTA DA neurons, the behavioural phenotype does not fully phenocopy genetic loss of oxytocin. Oxytocin knockout mice exhibit impaired habituation in the social recognition task10, whereas Nlgn3KO mice habituate normally but exhibit a selective deficit in the response to a novel conspecific. This is probably due to differential roles of Nlgn3 and oxytocin across several neural circuits and over development. Moreover, Nlgn3 loss-of-function also affects signalling through additional GPCRs23. We propose that pharmacological inhibition of MNKs may provide a new therapeutic strategy for neurodevelopmental conditions with altered translation homeostasis. Notably, MNK loss-of-function appears to be overall well tolerated. MNK1/2 double-knockout mice are viable46 and several MNK inhibitors are entering clinical trials for cancer therapy47. Previously available MNK inhibitors were greatly limited by specificity and brain penetrance. Our work not only highlights a new class of highly-specific, brain-penetrant MNK inhibitors but also expands their application from fragile X syndrome41 to a non-syndromic model of ASD. The common disruption in translational machinery and phenotypic rescue in two very different genetic models indicate that genetic heterogeneity of ASD might be reduced to a smaller number of cellular core processes. This raises the possibility that pharmacological interventions targeting such core processes may benefit broader subsets of patient populations.

 

A Highly Selective MNK Inhibitor Rescues Deficits Associated with Fragile X Syndrome in Mice 

Fragile X syndrome (FXS) is the most common inherited source of intellectual disability in humans. FXS is caused by mutations that trigger epigenetic silencing of the Fmr1 gene. Loss of Fmr1 results in increased activity of the mitogen-activated protein kinase (MAPK) pathway. An important downstream consequence is activation of the mitogen-activated protein kinase interacting protein kinase (MNK). MNK phosphorylates the mRNA cap-binding protein, eukaryotic initiation factor 4E (eIF4E). Excessive phosphorylation of eIF4E has been directly implicated in the cognitive and behavioral deficits associated with FXS. Pharmacological reduction of eIF4E phosphorylation is one potential strategy for FXS treatment. We demonstrate that systemic dosing of a highly specific, orally available MNK inhibitor, eFT508, attenuates numerous deficits associated with loss of Fmr1 in mice. eFT508 resolves a range of phenotypic abnormalities associated with FXS including macroorchidism, aberrant spinogenesis, and alterations in synaptic plasticity. Key behavioral deficits related to anxiety, social interaction, obsessive and repetitive activities, and object recognition are ameliorated by eFT508. Collectively, this work establishes eFT508 as a potential means to reverse deficits associated with FXS.

  

Conclusion

I think I have written enough about Oxytocin and Vasopressin.

The research is not entirely consistent regarding Vasopressin, but my assumption is that for my kind of autism I want an Oxytocin Agonist and a Vasopressin Agonist, some people might think it would be a Vasopressin Antagonist.

The good news is that there is significant research in humans, reported in previous posts, to support the use of both Oxytocin Agonist and a Vasopressin Agonist

I also think there will be both short-term, or immediate effects, from both treatments but also potentially different long-term effects from continued therapy, that is indeed suggested by the animal research models.  For example, neurite outgrowth is stimulated by oxytocin.  It is suggested that oxytocin may contribute to the regulation of scaffolding proteins expression.

Is it worth using oxytocin as a therapy to generate some extra hugs? You can argue both ways, but the longer-term benefits of correcting low oxytocin levels may be more profound.

The effects of vasopressin and oxytocin are somewhat overlapping. We know that low levels of vasopressin in spinal fluid are a good marker for autism, so putting a little extra vasopressin in the brain does not seem unreasonable.

As usual with the human body, the effects of oxytocin and vasopressin are different within the brain and in the rest of your body.  Also, the levels of these hormones in your blood are not a good predictor of their levels within the brain.  This is a reoccurring problem.  Because taking a spinal fluid sample is an invasive procedure, it is rarely taking place and then endless time and money is wasted on blood tests that may well send the doctor in the wrong direction, or just no direction.

It is highly likely that increasing Oxytocin and Vasopressin in the brain is going to affect aggressive behaviors, via actions in the Lateral Septum (LS).  Due to the role of GABA potentiating activity in the Lateral Septum (LS) you might expect a possible difference in bumetanide-responders and bumetanide non-responders (because GABA is acting as excitatory).

I would consider Oxytocin and Vasopressin as fine-tuning autistic behavior and you would have to personalize the dosage. In some people it might be a case of either or, rather than both.

Using MNK inhibitors to treat human Fragile-X looks a great idea and hopefully a commercialized therapy could then be trialed in broader autism.