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Showing posts with label Memantine. Show all posts
Showing posts with label Memantine. Show all posts

Monday, 3 April 2017

Different Types of Excitatory/Inhibitory Imbalance in Autism, Fragile-X & Schizophrenia


There is much written in the complex scientific literature about the Excitatory/Inhibitory (E/I) imbalance between neurotransmitters in autism. 

Many clinical trials have already been carried out, particularly in Fragile-X.  These trials were generally ruled as failures, in spite of a significant minority who responded quite well in some of these trials.

As we saw in the recent post on the stage II trial of bumetanide in severe autism, there is so much “background noise” in the results from these trials and it is easy to ignore a small group who are responders.  I think if you have less than 40%, or so, of positive responders they likely will get lost in the data. 

You inevitably get a significant minority who appear to respond to the placebo, because people with autism usually have good and bad days and testing is very subjective.

There are numerous positive anecdotes from people who participated in these “failed” trials.  If you have a child who only ever speaks single words, but while on the trial drug starts speaking full sentences and then reverts to single words after the trial, you do have to take note. I doubt this is a coincidence.

Here are some of the trialed drugs, just in Fragile-X, that were supposed to target the E/I imbalance:-

Metabotropic glutamate receptor 5 (mGluR5) antagonist

·        Mavoglurant

·        Lithium

mGluR5 negative allosteric modulator

·        Fenobam

N-methyl-D-aspartic acid (NMDA) antagonist

·        Memantine

Glutamate re-uptake promoter

·        Riluzole

Suggested to have effects on NMDA & mGluR5 & GABAA

·        Acamprosate

GABAB agonist

·        Arbaclofen

Positive allosteric modulator (PAM) of GABAA receptor

·        Ganaxolone


Best not to be too clever

Some things you might use to modify the E/I imbalance can appear to have the opposite effect, as was highlighted in the comments in the post below:-



So whilst it is always a good idea to try and figure things out, you may end up getting things the wrong way around, mixing up hypo and hyper.

The MIT people who work on Fragile-X are really clever and they have not figured it all out.


Fragile-X and Idiopathic Autism

Fragile-X gets a great deal of attention, because its biological basis is understood.  It results in a failure to express the fragile X mental retardation protein (FMRP), which is required for normal neural development.

We saw in the recent post about eIF4E, that this could lead to an E/I imbalance and then autism.




Our reader AJ started looking at elF4E and moved on to EIF4E- binding protein number 1.

In the green and orange boxes below you can find elF4E and elF4E-BP2.

This has likely sent some readers to sleep, but for those whose child has Fragile-X, I suggest they read on, because it is exactly here that the lack of fragile X mental retardation protein (FMRP) causes a big problem.  The interaction between FMRP on the binding proteins of elF4E, cause the problem with neuroligins (NLGNs), which causes the E/I imbalance.  Look at the red oval shape labeled FMRP and green egg-shaped NLGNs.

In which case, while AJ might naturally think Ribavirin is a bit risky for idiopathic autism, it might indeed be very effective in some Fragile-X.  You would hope some researcher would investigate this.




Can you have more than one type of E/I imbalance?

Readers whose child responds well to bumetanide probably wonder if they have solved their E/I imbalance.

I think they have most likely improved just one dysfunction that fits under the umbrella term E/I imbalance.  There are likely other dysfunctions that if treated could further improve cognition and behavior.

On the side of GABA, it looks like turning up the volume on α3 sub-unit and turning down the volume on α5 may help. We await the (expensive) Down syndrome drug Basmisanil for the latter, given that the cheap 80 year old drug Cardiazol is no longer widely available. Turning up the volume on α3 sub-unit can be achieved extremely cheaply, and safely, using a tiny dose of Clonazepam.

It does appear that targeting glutamate is going to be rewarding for at least some of those who respond to bumetanide.

One agonist of NMDA receptors is aspartic acid. Our reader Tyler is a fan of L-Aspartic Acid, that is sold as a supplement that may boost athletic performance.  

Others include D-Cycloserine, already used in autism trials; also D-Serine and L-Serine.

D-Serine is synthesized in the brain from L-serine, its enantiomer, it serves as a neuromodulator by co-activating NMDA receptors, making them able to open if they then also bind glutamate. D-serine is a potent agonist at the glycine site of NMDA receptors. For the receptor to open, glutamate and either glycine or D-serine must bind to it; in addition a pore blocker must not be bound (e.g. Mg2+ or Pb2+).

D-Serine is being studied as a potential treatment for schizophrenia and L-serine is in FDA-approved human clinical trials as a possible treatment for ALS/Motor neuron disease.  

You may be thinking, my kid has autism, what has this got to do with ALS/Motor neuron disease (from the ice bucket challenge)? Well one of the Fragile-X trial drugs at the beginning of this post is Riluzole, a drug developed for specially for ALS.  Although it does not help that much in ALS, it does something potentially very useful for some autism, ADHD and schizophrenia; it clears away excess glutamate.


Fragile-X is likely quite different to many other types of autism

I suspect that within Fragile-X there are many variations in the downstream biological dysfunctions and so that even within this definable group, there may be no universal therapies.  So for some people an mGluR5 antagonist may be appropriate, but not for others.

Even within this discrete group, we come back to the need for personalized medicine.

I do not think Fragile-X is a good model for broader autism.


Glutamate Therapies

There are not so many glutamate therapies, so while the guys at MIT might disapprove, it would not be hard to apply some thoughtful trial and error.

You have:

mGluR5

     ·        mGluR5 agonists (only research compounds)

·        mGluR5 positive allosteric modulators (only research compounds)

·        mGluR5 antagonists (Mavoglurant, Lithium)

·        mGluR5 negative allosteric modulators (Fenobam, Pu-erh tea decreases mGluR5 expression )

Today you can only really treat too much mGluR5 activity.  It there is too little activity, the required drugs are not yet available.  I wonder how many people with Fragile-X are drinking Pu-erh tea, it is widely available.


NMDA agonists

D-Cycloserine an antibiotic with similar structure to D-Alanine (D-Cycloserine was trialed in autism and schizophrenia)

ɑ-amino acids:

·         Aspartic acid (trialed and used  by Tyler, suggested for schizophrenia)

·         D-Serine (trialed in schizophrenia)




NMDA antagonists


·        Memantine (widely used off-label in autism, but failed in clinical trials)


·        Ketamine (trialed intra-nasal in autism)


Glutamate re-uptake promoters via GLT-1


·        Riluzole


·        Bromocriptine


·        Beta-lactam antibiotics









Thursday, 28 July 2016

Memantine – yet another failed Autism Trial


Memantine (Namenda/ Ebixa) is an Alzheimer’s drug that has been used off-label in autism for many years; but does it actually work?

More than a thousand people with autism have completed clinical trials and yet more trials are in progress. 

A few years ago, at the FDA’s request, the producer of the drug, Forest Laboratories, funded two clinical trials enrolling 903 children with autism.  The results were never fully published because the trials were deemed to have failed to find any positive effect and a note to reflect this is included in each pack of Namenda.

A quick look at ClinicalTrials.gov website shows yet more autism trials in the pipeline.


What is going on?

When Dr Chez made a trial in 2007 he found Memantine to be effective; he has since moved on to stem cell therapy which he also finds to be effective.

The latest study to be published includes Dr Hardan from Stanford, who published that study showing NAC to be effective in autism.  This time his study shows no positive effect.

If you look on the clinical trials site you can see some data for the primary endpoint used in the very big trial funded by Forest Laboratories.  It seems to show 517 responders.







By the time the results were reviewed in detail the conclusion drawn by Forest was “there was no statistically significant difference in the loss of therapeutic response rates between patients randomized to remain on full-dose memantine (n=153) and those randomized to switch to placebo”. 

In other words it does not work.

The drug itself now carries this note:-

8.4 Pediatric Use

The safety and effectiveness of memantine in pediatric patients have not been established.
Memantine failed to demonstrate efficacy in two 12-week controlled clinical studies of 578 pediatric patients aged 6-12 years with autism spectrum disorders (ASD), including autism, Asperger’s disorder, and Pervasive Development Disorder — Not Otherwise Specified (PDD-NOS). Memantine has not been studied in pediatric patients under 6 years of age or over 12 years of age. Memantine treatment was initiated at 3 mg/day and the dose was escalated to the target dose (weight-based) by week 6. Oral doses of memantine 3, 6, 9, or 15 mg extended-release capsules were administered once daily to patients with weights < 20 kg, 20-39 kg, 40-59 kg and ≥ 60 kg, respectively.
In a randomized, 12-week double-blind, placebo-controlled parallel study (Study A) in patients with autism, there was no statistically significant difference in the Social Responsiveness Scale (SRS) total raw score between patients randomized to memantine (n=54) and those randomized to placebo (n=53). In a 12-week responder-enriched randomized withdrawal study (Study B) in 471 patients with ASD, there was no statistically significant difference in the loss of therapeutic response rates between patients randomized to remain on full-dose memantine (n=153) and those randomized to switch to placebo (n=158).


So if it does not work, why do researchers continue to carry out further trials, like the recent one below, including Hardan?



OBJECTIVE:

Abnormal glutamatergic neurotransmission is implicated in the pathophysiology of autism spectrum disorder (ASD). In this study, the safety, tolerability, and efficacy of the glutamatergic N-methyl-d-aspartate (NMDA) receptor antagonist memantine (once-daily extended-release [ER]) were investigated in children with autism in a randomized, placebo-controlled, 12 week trial and a 48 week open-label extension.

METHODS:

A total of 121 children 6-12 years of age with Diagnostic and Statistical Manual of Mental Disorders, 4th ed., Text Revision (DSM-IV-TR)-defined autistic disorder were randomized (1:1) to placebo or memantine ER for 12 weeks; 104 children entered the subsequent extension trial. Maximum memantine doses were determined by body weight and ranged from 3 to 15 mg/day.

RESULTS:

There was one serious adverse event (SAE) (affective disorder, with memantine) in the 12 week study and one SAE (lobar pneumonia) in the 48 week extension; both were deemed unrelated to treatment. Other AEs were considered mild or moderate and most were deemed not related to treatment. No clinically significant changes occurred in clinical laboratory values, vital signs, or electrocardiogram (ECG). There was no significant between-group difference on the primary efficacy outcome of caregiver/parent ratings on the Social Responsiveness Scale (SRS), although an improvement over baseline at Week 12 was observed in both groups. A trend for improvement at the end of the 48 week extension was observed. No improvements in the active group were observed on any of the secondary end-points, with one communication measure showing significant worsening with memantine compared with placebo (p = 0.02) after 12 weeks.

CONCLUSIONS:

This trial did not demonstrate clinical efficacy of memantine ER in autism; however, the tolerability and safety data were reassuring. Our results could inform future trial design in this population and may facilitate the investigation of memantine ER for other clinical applications.
  
Dr Chez? 

So how reliable then are Dr Chez’s other findings?  He is a "big name" in autism research.

Back in 2007 Dr Chez published a very positive study on the use of Memantine in autism. 

Memantine as adjunctive therapy in children diagnosed with autistic spectrum disorders: an observationof initial clinical response and maintenance tolerability.

 

Abstract

Autism and Pervasive Developmental Disorder Not Otherwise Specified are common developmental problems often seen by child neurologists. There are currently no cures for these lifelong and socially impairing conditions that affect core domains of human behavior such as language, social interaction, and social awareness. The etiology may be multifactorial and may include autoimmune, genetic, neuroanatomic, and possibly excessive glutaminergic mechanisms. Because memantine is a moderate affinity antagonist of the N-methylD-aspartic acid (NMDA) glutamate receptor, this drug was hypothesized to potentially modulate learning, block excessive glutamate effects that can include neuroinflammatory activity, and influence neuroglial activity in autism and Pervasive Developmental Disorder Not Otherwise Specified. Open-label add-on therapy was offered to 151 patients with prior diagnoses of autism or Pervasive Developmental Disorder Not Otherwise Specified over a 21-month period. To generate a clinician-derived Clinical Global Impression Improvement score for language, behavior, and self-stimulatory behaviors, the primary author observed the subjects and questioned their caretakers within 4 to 8 weeks of the initiation of therapy. Chronic maintenance therapy with the drug was continued if there were no negative side effects. Results showed significant improvements in open-label use for language function, social behavior, and self-stimulatory behaviors, although self-stimulatory behaviors comparatively improved to a lesser degree. Chronic use so far appears to have no serious side effects.


Making sense of Memantine

Personally, I think it likely that Memantine may indeed have a positive effect in some people with autism.  For most people it probably does no good, but no harm, so it is a harmless placebo that may make the parents feel better and gives the doctor something to prescribe.

Memantine and the very similar Galantamine probably do deserve a place in the long list of drugs and supplements that may be effective in some people.  But how great is that “effect”?  I suspect this is the problem; it is big enough for Dr Chez but not big enough for the others.

I suspect this will be a recurring problem in almost all future autism drug trials.  What is a responder?  How big an effect is a worthwhile effect?

I think a better approach would be to focus on the so-called responders identified by Dr Chez and others.  Document the claimed positive effects and then see if these effects continue when the responders are given a dummy placebo.

This is the approach I use in my trials; when I stop a therapy, I look to see if there is a change.  When you suspend an effective therapy things should get worse.

The hundreds or thousands of kids currently on Memantine should do the same; take a break and see if there is any change, be it positive or negative. 

Many people believe no valid treatments for autism exist and that those thinking otherwise are all deluded.

I think that many people are giving their kids drugs and supplements of no therapeutic value and in some cases are making the situation worse.

However, effective therapies do exist for many people with autism and they stand up to scrutiny.  The effect is apparent to third parties, like teachers and therapists, and when you stop the therapy the positive effect is lost and people notice, only to return when it is restarted.  Then you know it is not wishful thinking and at that point what the FDA says does not really matter and you do not need bother with what subsequent trials say.

So when a reader asked me what I thought about the recent “failed” trial of NAC, to treat social impairment in autism, I took a very relaxed view.  If they had identified 50 kids with classic autism and stereotypy and looked at whether NAC reduced this, I would take note.  They choose the wrong primary endpoint, social impairment, and wasted a lot of money.


A randomized placebo-controlled pilot study of N-acetylcysteine in youth with autism spectrum disorder

Conclusions
The results of this trial indicate that NAC treatment was well tolerated, had the expected effect of boosting GSH production, but had no significant impact on social impairment in youth with ASD
.
      
I only wait to see what happens when Ben Ari publishes the results of his large trial on Bumetanide.  Whatever data they choose to collect, is it going to convince the European Medicines Agency that it is an effective therapy?  I hope so, but nothing would surprise me.

I would love to know how Dr Chez rationalizes the fact that so many others cannot replicate his positive research findings.  But he keeps on going.

Rather off-topic, a recent comment on my post on Clonidine, informed us that this drug, often prescribed off-label in autism and ADHD, really is acting as a sedative to calm the person down. So no effect on core autism.  Sedation does have a role to play in some people’s disorders.  Very low doses of Mirtazapine (Remeron) are also sedating via its effect of central H1 receptors; it occurred to me that this might be a safe long term therapy for some "out of control" people with severe autism; likely safer than the usual antipsychotics. 







Wednesday, 2 December 2015

“Autism treatments proposed by clinical studies and human genetics are complementary” & the NSAID Ponstan as a Novel Autism Therapy





Today’s post was not my idea at all, it was the author of one of the papers who has drawn my attention to the subject.

Genetic studies are complicated and are not the sort of thing I would have chosen to read, let alone write about, before starting this blog. 



The optimal time to initiate pharmacological 
intervention in Autism?


However, much of the complex subject matter has now already been covered, step by step, in earlier posts. Regular readers should not feel put off.

It is perhaps easier to think about ion channel dysfunctions, or channelopathies.  Some of the key genetic dysfunctions produce these channelopathies.  There are many posts in this blog about channelopathies, partly because many therapies already exist to treat them.

Then we have the complex signaling pathways which are often the subject of cancer research, but we have seen that certain ones like RAS and PTEN are key to conditions like some autism and some MR/ID.

So it is not a big leap therefore to consider the findings of a statistical reassessment of the existing genome-wide association studies (GWAS).  As is often the case in medical science, it is the acronyms/abbreviations, like GWAS, that make it look more complex than it really is.

If you only ever read one paper about the genetics of autism, I suggest you make it this one.

Fortunately, the conclusion from the genetic study really fits nicely with the clinical studies reviewed on this blog and even my own first-hand experience of investigating and treating my n=1 case of autism.


Knut, the Biometrician

It was Knut who left a brief comment on this blog and, after a little digging, I was very surprised how much a statistician/biometrician could figure out about autism, from re-analyzing the existing genome-wide association studies (GWAS).

I think the Simons Foundation could save themselves a decade or two by giving him a call.



The Research

For those wanting the science-lite version, there is a short article reviewing the research in lay terms:-


Biostatistics provides clues to understanding autism: an interview with Dr Knut M. Wittkowski



“Hence, modulation of ion channels in children at the age of about 12 months, when the first symptoms of autism can be detected, may prevent progression to the more severe end of the spectrum.” .



The actual research paper is here:-

You may find it heavy going and I have highlighted some key parts.


A novel computational biostatistics approach implies impaired dephosphorylationof growth factor receptors as associated with severity of autism

  
“Despite evidence for a likely involvement of de novo and environmental or epigenetic risk factors, including maternal antibodies or stress during pregnancy  and paternal age, we contend that coding variations contribute substantially to the heritability of ASD and can be successfully detected and assembled into connected pathways with GWAS—if the experimental design, the primary outcome, the statistical methods used, and the decision rules applied were better targeted toward the particulars of non-randomized studies of common diseases.”


The data comes from the Autism Genome Project (AGP), and there are two sets of data AGPI and AGPPII.

The third data set is for Childhood Absence Epilepsy (CAE)

What I would call Classic Autism, others call severe autism or autistic disorder; Knut calls it Strict Definition Autism (SDA).  HFA is high functioning autism, much of which is Asperger’s Syndrome.



“Study design We aimed at risk factors specific to strict definition autism (SDA) by comparing case subpopulations meeting the definition of SDA and milder cases with ASD (excluding SDA), for which we here use the term ‘highfunctioning autism’ (HFA). To reduce variance, we included only subjects of European ancestry genotyped on the more frequently used platform in either stage. In AGP II, we also excluded female cases because of confounding between chip platform and disease severity. The total number of subjects included (m: male/f: female) was 547/98 (SDA) and 358/68 (HFA) in AGP I and 375 (SDA) and 201 (HFA) in AGP II.

Overall, the results (see Supplementary Figure 1 for a Manhattan plot) are highly consistent with previously proposed aspects of the etiology of ASD. The clusters of genes implicated in both of the independent stages (Figure 2a/b) consistently overlap with our published CAE results (Figure 2c), confirming the involvement of ion channels (top right) and signaling downstream of RAS (bottom left), with two noticeable additional gene clusters in ASD. Both stages implicate several genes involved in deactivation of growth factor (GF) receptors (Figure 2a/b, top left) as ASD-specific risk factors and chloride (Cl − ) signaling, either through Ca2+ activated Cl− channels









Click to enlarge the figure 




A new term is PTPR (protein tyrosine phosphatases receptor), just to confuse us it is also called RPTP.

Receptor Protein Tyrosine Phosphatases in Nervous System Development

 

For example, the receptor protein tyrosine phosphatases gamma (PTPRG) and zeta (PTPRZ) are expressed primarily in the nervous system and mediate cell adhesion and signaling events during development.

In an earlier post I highlighted the numerous dysfunctions in growth factors (GF) in autism.  Knut is highlighting here the effect of PTPR on growth factors.  Later it is suggested that this cascade of GF dysfunctions could be halted, pharmacologically if it was identified very early.  But, as Courchesne from UC San Diego noted, by the time people have been identified as having autism, around three years old, the accelerated brain growth has already run its course.

You would need to intervene around one year old.



Broad evidence for involvement of PTPRs One of the most striking observations is the involvement of at least five PTPRs in ASD (Figure 2, 10 o’clock position). PTPRs (Table 1e) regulate GF signaling through reversible protein tyrosine dephosphorylation.72 PTPRT (90th/20th, 8.57) was implicated in ASD by a deletion73 (Table S2 AU018704) and a somatic mutation










It was my post pondering the reasons for the positive effect of potassium supplementation that drew Knut’s attention to this blog.  Now we move on to Knut’s ideas on potassium and chloride channels.



K+ and Cl− ion channels as drug targets

Aside from PTPRs (Figure 2, 10 o’clock) as a risk factor for protracted GF signaling, our results suggest a second functional cluster of genes, involved in Cl− transport and signaling, as specific to ASD (Table 1f). In AGP I, the CaCCs ANO4 and ANO7 scored 1st and 70th, respectively. In AGP II, the lysosome membrane H+ /Cl- exchange transporter CLCN7 scored 21st, followed by CAMK2A, which regulates ion channels, including anoctamins82 (55th), and LRRC7 (densin-180), which regulates CAMK2A83 (Figure 2a/b, 2 o’clock). The role of the anoctamins in pathophysiology is not well understood, except that CaCC activity in some neurons is predicted to be excitatory84 and to have a role in neuropathic pain or nerve regeneration. More recently, CaCCs have also been suggested as involved in ‘neurite (re)growth’. Finally, we compared the HFA and SDA cases as separate groups against all parental controls in the larger AGP I population. Overall, the level of significance is lower and the enrichment is less pronounced, especially for the SDA cases (Supplementary Figure 9), as expected when cases and some controls are related. For the HFA cases (Figure 4, and Supplementary Figure 8), however, a second anoctamin, ANO2, located on the other arm of chromosome 12, competes with ANO4 (Figure 1, left), for the most significant gene among the result. Hence, drugs targeting anoctamins might have broader benefits for the treatment of ASD than in preventing progression to more severe forms of autism. ANO2 and ANO6 are associated with panic disorder and major depressive disorder, respectively. ANO3, ANO4, ANO8 and ANO10, but not ANO1, are also expressed in neuronal tissue.86 As ‘druggable channels’, anoctamins ‘may be ideal pharmacological targets to control physiological function or to correct defects in diseases’.  Few drugs, however, target individual anoctamins or even exclusively CaCCs. Cl− channel blockers such as fenamates, for instance, may decrease neuronal excitability primarily by activating Ca2+-dependent outward rectifying K+ channels.



Here is a follow-up paper with consideration of the possible next steps.





Gene gene environment behavior development interaction at the core of autism:

Here, we combine a recent wide-locus approach with novel decision strategies fine-tuned to GWAS. With these methodological advances, mechanistically related clusters of genes and novel treatment options, including prevention of more severe forms of ASD, can now be suggested from studies of a few hundred narrowly defined cases only.
(Nonsyndromic) autism starts with largely unknown prenatal events (: age, : virus/stress ...)
• Mutations in growth factor regulators (PTPRs) lead to neuronal overgrowth (brain sizes).
• Mutations in K+/Cl− channels cause Ca2+ mediated over excitation of neurons (“intense world”).
• Stressful environments (urbanization) contribute to epistatic interaction (increasing prevalence).
• This GGE interaction causes “migraine-like” experiences during the “stranger anxiety” period where children learn verbal/social skills, leading to behavioral maladaptation (“tune-out”).
The lack of verbal/social stimuli causes “patches of disorganization” (Stoner 2014, NEJM) as a form of developmental maladaptation when underutilized brain areas are permanently “pruned”. The PTPRs point to a short window of opportunity (WoO) for pharmacological intervention:
• Treatment has to begin as early as possible, while neurons are still growing (12 months of age. Broad support for the proposed unifying etiology and the 2nd year of life as the WoO:
• Regression (“loss of language”) seen in some children >12 mos of age.
• “Patches of disorganization” in >2 yr old brains.
• Romanian orphans developed “quasi-autism” when placed into foster care at >24 mos of age. 
• Hearing impairment leading to intellectual disability when diagnosed >24 mos of age.

 A rational drug target: treating either of two epistatic risk factors suffices:
• Blocking growth factors (Gleevac, ...) is unacceptable in children merely at risk of ASD.
• Ion channel modulators have been used in small children for arthritis and seizures.








Here is a response to Knut’s first paper from a professor at the UCLA medical school who suggests the combination of the specific NSAID and bumetanide. 
The professor would better understand the mechanism of action of bumetanide in autism if he read Ben Ari’s research more thoroughly, or even this blog.
  
  
The article by Wittkowski et al.1 reports results of human genetic studies that suggest that a nonsteroidal anti-inflammatory drug (NSAID) given for a few months from the time of the first symptoms might help some children who are at risk of developing more severe forms of atrial septal defect.
While the authors mention the recent article by Lemonnier et al.,2 which reported that a clinical study of the diuretic Bumetanide was partially effective in children with milder forms of autism, they seem to have overlooked that these two treatments may well be complementary, leading to sequential interventions, each targeting specific risks related to well-defined stages in the development of brain and social interactions.
Since abnormal brain development in autistic disorder goes through different stages from infancy to childhood, targeting different developmental stages with different treatment interventions may well be necessary to foster continued normalization of brain growth.
Bumetanide is known to block inward chloride transporters, yet the relation of this mechanism to the etiology of autism is unknown. Wittkowski et al. identified mutations in calcium-activated (outward) chloride channels as associated with autistic disorder, suggesting loss-of-function mutations in anoctamins as one of the risk factors for autism. This provides a testable hypothesis for the mechanism by which Bumetanide alleviates symptoms of autism. For example, mouse models could test whether Bumetanide ameliorates a stress-induced phenotype caused by a knockout/down in ANO2 and/or ANO4.
A second cluster of genes identified receptor protein tyrosine phosphatases, which downregulate growth factors. These findings support the notion that successful treatment should start as early as possible,3 while neuronal development still takes place.
The rationale for combining these two treatments rests on the fact that Bumetanide is contraindicated in infancy because it is known to interfere with neuronal development when used long term. In contrast, the NSAID proposed in the second study has been given for decades to children with juvenile idiopathic arthritis from 6 months of age on, with no adverse effects on brain development. It is known to modulate chloride channels (see above) as well as potassium channels.4
In conclusion, I wish to extend their hypothesis based on the synergy of the two treatment approaches: (1) early treatment with NSAID can reduce early maladaptive behaviors that cause abnormal pruning of neurons in the cortical areas; (2) these children could subsequently benefit from Bumetanide, which would compensate for the primary ion channel defect, but could not reverse the secondary effect of abnormal pruning.
This hypothesis allows for a novel two-way interaction between behavior and molecular events. Traditionally, one assumes that molecular events determine behavior. The new hypothesis, based on human genetics, also allows for symptoms (such as the absence of social interactions, delayed speech onset and language development) during certain sensitive periods to change molecular events (pruning of neurons in areas required for normal development).



Therapeutic implications from the genetic analysis

Some of the therapies that Knut is proposing, based on the genetic analysis, have already been reviewed in this blog.  Some have not.  A few therapeutic ideas in this blog actually target genes Knut has identified, but not highlighted a therapy.

I will just review the drugs and genes that the above study highlights.


Benzodiazepines

Low dose clonazepam fits in this category.  We have the work of Professor Catterall to support its use.  At higher doses, benzodiazepines have different effects but use is associated with various troubling side effects.


Bumetanide

Bumetanide is at the core of my suggested therapy for classic autism or what Knut calls SDA (strict definition autism).  We have Ben-Ari to thank for this



Fenamates (ANO 2/4/7 & KCNMA1)

Here Knut is trying to target the ion channels expressed by the genes ANO 2/4/7 & KCNMA1. 

·        ANO 2/4/7 are calcium activated chloride channels. (CACCs)


·        KCNMA1 is a calcium activated potassium channel.  KCNMA1 encodes the ion channel KCa1.1, otherwise known as BK (big potassium).  This was the subject of post that I never got round to publishing.
  
Fenamates are an important group of clinically used non-steroidal anti-inflammatory drugs (NSAIDs), but they have other effects beyond being anti-inflammatory.  They act as CaCC inhibitors and also stimulate BKCa channel activity.
  

Fenamates stimulate BKCachannel osteoblast-like MG-63 cells activity in the human.


 The fenamates can stimulate BKCa channel activity in a manner that seems to be independent of the action of these drugs on the prostaglandin pathway”


Molecular and functional significance of Ca2+-activated Cl− channels in pulmonary arterial smooth muscle



Of this “first generation” of CaCC inhibitors, NFA (a fenamate called niflumic acid)  is the most potent blocker of these channels and the compound most frequently used to investigate the physiological role of CaCCs”



Choice of Fenamate
There are several fenamate-type NSAIDs, but one is a very well used generic drug, Mefenamic acid known as Ponstan, Ponalar, Ponstyl, Ponstel and other generic names.  It is even available as a syrup for children.
 It is not available in all countries.



Gabapentin


Gabapentin is used primarily to treat seizures and neuropathic pain. It is also commonly prescribed for many off-label uses, such as treatment of anxiety disorders, insomnia, and bipolar disorder.

Some people with autism are prescribed Gabapentin.  Some people suffer side effects and others do not.

If you have a dysfunction of voltage operated calcium channels, Gabapentin should help.



Memantine

This is all about modifying NMDA receptors.  Memantine is but one method.




Minocycline

Minocycline is an antibiotic with several little known extra properties.  In autism, we looked at its ability to reduce microglial activation and so improve autism.  A clinical trial showed that it did not help autism.

Minocycline also affects MMP-9.  MMP-9 is an enzyme found to be associated with numerous pathological processes, including cancer, immunologic and cardiovascular diseases.

High MMP-9 activity levels in fragile X syndrome are lowered by minocycline.


 “ The results of this study suggest that, in humans, activity levels of MMP-9 are lowered by minocycline and that, in some cases, changes in MMP-9 activity are positively associated with improvement based on clinical measures.


So if you are treating a case of Fragile-X, or partial "Fragile-X-like" autism, better take note.



Rapamycin

Rapamycin and mTOR was the subject of the following post:

mTOR – Indirect inhibition, the Holy Grail for Life Extension and Perhaps Some Autism



Both too much and too little mTOR can occur in autism.




Conclusion

My conclusion is probably different to yours.

For me, it seems that all the pieces really are fitting together and so this blog on the cause and treatment of classic autism will eventually cover the current scientific knowledge, in its entirety.  No complex areas are off limits, because in the end they are not as complex as they seem, when you lift the veil of jargon and acronyms.

From the all-important therapeutic perspective, new insights from today’s post are:-

·        Those with a dysfunction of voltage operated calcium channels might want to give Gabapentin (Neurontin) a try.

·        The fenamate-type NSAID mefenamic acid,  widely known as Ponstan, really should be tested, either at home, or in a clinical trial.

This statistical analysis is based on “all autism”, so any one person would be highly unlikely to have all the mentioned dysfunctions.  These are the most common genetic dysfunctions and many can both hypo and hyper, as in the case of NMDA dysfunctions and indeed mTOR. 

In Knut’s chart, I would add a green line pointing to RAS and PTEN with the word Atorvastatin.  Baclofen would point to the growth factors.  Verapamil would point in multiple places.

The motto of University of Tübingen, where Knut originally comes from, is Attempto !  The Latin for "I dare".

This might be a useful motto for readers of this blog, and also a good tittle for a book on treating autism.