Cognitive Loss/Impaired Sensory Gating from HCN Channels - Recovered by PDE4 Inhibition or an α2A Receptor Agonist

Today we have a complex dysfunction, but we have a plausible understanding of the detailed biological underpinnings and several therapeutic options. It is relevant to people with autism who have impaired sensory gating (they find noises like a clock ticking annoying), and perhaps those who struggle with complex thought. It is very likely to be disturbed in some people with ADHD and many with schizophrenia.

Trouble in the Pre-Frontal Cortex

For a recap on sensory gating, here is an earlier post:-

Sensory Gating in Autism, Particularly Asperger's

Today’s dysfunction relates to HCN channels located on those tiny dendritic spines in a part of the brain called the pre-frontal cortex. These are a type of voltage gated potassium channel found in your brain and heart, there are 4 types, it looks to me that HCN2 is the key one today.

The pre-frontal cortex (PFC) is seen as the part of the brain most affected by mental illness (schizophrenia, bipolar, ADHD etc.), although medicine’s current understanding looks rather medieval to me.

These HCN channels can open when they are exposed to cAMP (cyclic adenosine monophosphate). When open, the information can no longer flow into the cell, and thus the network (created by numerous interacting neurons) is effectively disconnected.

By keeping these channels closed, it is thought that you can improve working memory and reducing distractibility. Now you might think distractibility is an odd word, and it is not a word I expected to encounter, what it really means is impaired sensory gating. This is a core feature of Asperger’s, ADHD and schizophrenia.

One of the key risk genes for schizophrenia, DISC1, also affects HCN channels and this may account for some of the cognitive deficit found in schizophrenia. High level thinking is particularly affected.  It is thought that loss of DISC1 function in the PFC would likely prevent proper PDE4 function, leading to a dysregulated build-up of cAMP in dendritic spines resulting in excessive opening of HCN channels

Role of disrupted in schizophrenia 1 (DISC1) in stress-induced prefrontal cognitive dysfunction

I did wonder how nicotine fits in, since in earlier post we saw that α7 nAChR agonists, like nicotine, improve sensory gating and indeed that people with schizophrenia tend to be smokers. It turns out that nicotine is also an HCN channel blocker. For a change, everything seems to fit nicely together. There are different ways to block HCN channels, some of which are indirect. One common ADHD drug, Guanfacine, keeps these channels closed, but in a surprising way.

Alpha-2A adrenergic receptors near the HCN channels, on those dendritic spines, inhibit the production of cAMP and the HCN channels stay closed, allowing the information to pass through into the cell, connecting the network. These Alpha-2A adrenergic  receptors are stimulated by a natural brain chemical norepinephrine, or by drugs like Guanfacine.

Stress appears to flood PFC neurons with cAMP, which opens HCN channels, temporarily disconnects networks, and impairs higher cognitive abilities.

This would explain why stress makes people’s sensory gating problems get worse. So someone with Asperger’s would get more distracted/disturbed at exam time at school for example, or when he goes for a job interview. Reducing stress is another method to improve sensory gating and indeed cognition. In Monty, aged 14 with ASD, the only time he exhibits significantly impaired sensory gating, is when he has stopped all his Polypill therapies for several days. I think stress/anxiety is what has changed and this opens those HCN channels. Then even the sound of someone eating food next to him makes him angry.

Excessive opening of HCN channels might underlie many lapses in higher cognitive function.

While the researchers at Yale patented the idea of HCN blockers to improve cognition, we can see how other existing ideas to improve cognition may indeed have the same mechanism, most notably PDE4 inhibitors.

The University of Maastricht holds patents on the use of Roflumilast, a PDE4 inhibitor, to improve cognition; most interestingly, this takes effect at one fifth of the COPD dosage, for which it is an approved drug. At high doses PDE4 inhibitors have annoying side effects, but at low doses they tend to be trouble-free.

One effect of a PDE4 inhibitor is that it reduces cAMP. So a PDE4 inhibitor acts indirectly like an HCN blocker.

Not surprisingly recent research showed that low doses of Roflumilast improves sensory gating in those affected by this issue.

So rather than waiting for a brain selective HCN blocker, the potential exists to use a one fifth dose of Roflumilast today. This is something that should indeed be investigated across different types of cognitive dysfunction.

There are numerous dysfunctions that can impair cognition and they can occur in different diagnosis. For example impaired autophagy is a key feature of Huntington’s, impaired remyelination defines multiple sclerosis, low levels of nerve growth factor are a key feature of Rett syndrome. Less severe dysfunctions of these processes occur in entirely different conditions.

It is thought that people with Alzheimer’s might benefit from PDE4 inhibition. If it was me, I would try it in all types of dementia or cognitive loss of any kind.

PDE4 Inhibitors

There have been many mentions of PDE4 inhibitors elsewhere in this blog. They are broadly anti-inflammatory and anti-oxidant, but currently only widely used to treat asthma in Japan and COPD in Western countries. COPD is a kind of very severe asthma.

Traditionally a PDE4 inhibitor is thought of as drug used to block the degradative action of phosphodiesterase 4 (PDE4) on cyclic adenosine monophosphate (cAMP). That all sound complicated, just think of it as increasing cAMP.

Now cAMP is a messenger in many biological processes, one of which relates to PKA (Protein Kinase A). In autism we know that PKA, PKB and PKC are often disturbed. These PKs are very important because they have the ability to literally change the function of thousands of proteins in your body. This is similar to how epigenetic tags can switch on or switch off a particular gene. PKs, via a different mechanism we will look at in another post, change the function of proteins, so it is very important that you have the correct level of PKA, PKB and PKC.

We saw in a recent post that the Pitt Hopkins gene TCF4 is regulated by PKA and that under-expression of TCF4 is also a feature of some ID and schizophrenia. So more PKA, please.

The Intellectual Disability and Schizophrenia Associated Transcription Factor TCF4 Is Regulated by Neuronal Activity and Protein Kinase A 

You can use a PDE4 inhibitor to increase cAMP, which then increases PKA.

Other effects of PDE4 inhibitors

Today’s post is about sensory gating and the effect here of PDE4 inhibitors is via the effect of cAMP on those HCN channels in your tiny dendritic spines.

There are numerous other effects of PDE4 that may also be therapeutic. One interesting effect is that inhibition of PDE4 can mimic calorie restriction by activating AMPK/SIRT1 pathway.

Calorie restriction has just been shown in a large trial to be able to reverse type 2 diabetes, if initiated with a few years of the disease developing.

Humans have evolved based to periods of feast and famine. Periods of fasting may be therapeutic for many modern conditions.

Not surprisingly one side effect of PDE4 inhibitors is weight loss. Many psychiatric drugs cause troubling weight gain.

Acute administration of Roflumilast enhances sensory gating in healthy young humans in a randomized trial. 

Abstract

 

INTRODUCTION:

Sensory gating is a process involved in early information processing which prevents overstimulation of higher cortical areas by filtering sensory information. Research has shown that the process of sensory gating is disrupted in patients suffering from clinical disorders including attention deficit hyper activity disorder, schizophrenia, and Alzheimer's disease. Phosphodiesterase (PDE) inhibitors have received an increased interest as a tool to improve cognitive performance in both animals and man, including sensory gating.

METHODS:

The current study investigated the effects of the PDE4 inhibitor Roflumilast in a sensory gating paradigm in 20 healthy young human volunteers (age range 18-30 years). We applied a placebo-controlled randomized cross-over design and tested three doses (100, 300, 1000 μg).

RESULTS:

Results show that Roflumilast improves sensory gating in healthy young human volunteers only at the 100-μg dose. The effective dose of 100 μg is five times lower than the clinically approved dose for the treatment of acute exacerbations in chronic obstructive pulmonary disease (COPD). No side-effects, such as nausea and emesis, were observed at this dose. This means Roflumilast shows a beneficial effect on gating at a dose that had no adverse effects reported following single-dose administration in the present study.

CONCLUSION:

The PDE4 inhibitor Roflumilast has a favourable side-effect profile at a cognitively effective dose and could be considered as a treatment in disorders affected by disrupted sensory gating.

Treating Cognitive Impairment with Roflumilast, Maastricht University

Background Information

Selective phosphodiesterase (PDE) inhibition has been considered as a very promising target for cognition enhancement.

Roflumilast is a PDE4 inhibitor that has been developed by Takeda for Chronic Obstructive Pulmonary Disease (COPD). In recent year, Maastricht University has been collaborating with Takeda to develop Roflumilast for cognitive impairments

In 2015 Takeda sold COPD indication of Roflumilast to AstraZeneca, and ownership of IP for treatment of cognitive impairment returned to Maastricht University.

Compelling clinical results

A single administration of Roflumilast improves episodic memory in mice, and in young and elderly healthy subjects at a non-emetic dose

As shown in the figure, healthy (A) and memory impaired (B) elderly subjects showed better performances in the delayed recall of the Verbal Learning Task after roflumilast

Key Features and Advantages

Opportunities to reposition a clinically-proven safe compound with a well-established pharmacology.

Compelling preclinical and clinical evidences showing that Roflumilast effectively deliver to the brain to produce robust cognitive enhancement.

Pro-cognitive effects at low dose (5 times lower than COPD indication), which allows to circumvent the emetic effects commonly observed with other PDE4 inhibitors

Maastricht University has a strong IP protection extending to at least 2033.

Effect of Roflumilast on cognitive function in schizophrenia

PDE inhibitors in psychiatry--future options for dementia, depression and schizophrenia?

Author information

Abstract

Phosphodiesterases are key enzymes in cellular signalling pathways. They degrade cyclic nucleotides and their inhibition via specific inhibitors offers unique 'receptor-independent' opportunities to modify cellular function. An increasing number of in vitro and animal model studies point to innovative treatment options in neurology and psychiatry. This review critiques a selection of recent studies and developments with a focus on dementia/neuroprotection, depression and schizophrenia. Despite increased interest among the clinical neurosciences, there are still no approved PDE inhibitors for clinical use in neurology or psychiatry. Adverse effects are a major impediment for clinical approval. It is therefore necessary to search for more specific inhibitors at the level of different PDE sub-families and isoforms.

Brain Networks Strengthened By Closing Ion Channels, Research Could Lead To ADHD Treatment

The current study found that brain cells in PFC contain ion channels called hyperpolarization-activated cyclic nucleotide-gated channels (HCN) that reside on dendritic spines, the tiny protrusions on neurons that are specialized for receiving information. These channels can open when they are exposed to cAMP (cyclic adenosine monophosphate). When open, the information can no longer flow into the cell, and thus the network is effectively disconnected. Arnsten said inhibiting cAMP closes the channels and allows the network to reconnect.

Guanfacine can strengthen the connectivity of these networks by keeping these channels closed, thus improving working memory and reducing distractibility," she said. "This is the first time we have observed the mechanism of action of a psychotropic medication in such depth, at the level of ion channels."

Arnsten said the excessive opening of HCN channels might underlie many lapses in higher cognitive function. Stress, for example, appears to flood PFC neurons with cAMP, which opens HCN channels, temporarily disconnects networks, and impairs higher cognitive abilities.

The study also found alpha-2A adrenergic receptors near the channels that inhibit the production of cAMP and allow the information to pass through into the cell, connecting the network. These receptors are stimulated by a natural brain chemical  norepinephrine or by medications like guanfacine.

 “Guanfacine can strengthen the connectivity of these networks by keeping these channels closed, thus improving working memory and reducing distractibility,” she said. “This is the first time we have observed the mechanism of action of a psychotropic medication in such depth, at the level of ion channels.”

Yale has submitted a patent application on the use of HCN blockers for the treatment of PFC cognitive deficits based on the data reported in the Cell paper.

The full Yale paper:

α2A-Adrenoceptors Strengthen Working Memory Networks by Inhibiting cAMP-HCN Channel Signaling in Prefrontal Cortex

Guanfacine for the Treatment of Cognitive Disorders: A Century of Discoveries at Yale

The prefrontal cortex (PFC) is among the most evolved brain regions, contributing to our highest order cognitive abilities. It regulates behavior, thought, and emotion using working memory. Many cognitive disorders involve impairments of the PFC. A century of discoveries at Yale Medical School has revealed the neurobiology of PFC cognitive functions, as well as the molecular needs of these circuits. This work has led to the identification of therapeutic targets to treat cognitive disorders. Recent research has found that the noradrenergic α2A agonist guanfacine can improve PFC function by strengthening PFC network connections via inhibition of cAMP-potassium channel signaling in postsynaptic spines. Guanfacine is now being used to treat a variety of PFC cognitive disorders, including Tourette’s Syndrome and Attention Deficit Hyperactivity Disorder (ADHD). This article reviews the history of Yale discoveries on the neurobiology of PFC working memory function and the identification of guanfacine for treating cognitive disorders.

Nicotine blocks the hyperpolarization-activated current Ih and severely impairs the oscillatory behavior of oriens-lacunosum moleculare interneurons.

Molecular modeling suggests that, similarly to ZD 7288, nicotine and epibatidine directly bind to the inner pore of the HCN channels. It is therefore likely that nicotine severely influences rhythmogenesis and high cognitive functions in smokers.

Modulation of HCN channels in lateral septum by nicotine

Conclusion

I think many people stand to benefit from the drugs mentioned in today’s post, but for different biological reasons. A person with Pitt Hopkins may benefit from Roflumilast because it will upregulate PKA and then increase expression of their remaining TCF4 gene.

In a person with schizophrenia there are multiple reasons these drugs might help them and it will depend on which genes they have that are misexpressed (TCF4, DISC1 etc.).

In a person with idiopathic Asperger’s and impaired sensory gating it looks like the effect on HCN channels is what is important.

I think low dose Roflumilast has great potential for many. The Japanese drug Ibudilast very likely will provide similar benefits, but at what dosage?

PDE4 inhibitors do have side effects at higher doses in part because there are several different types of PDE4 (PDE4A, PDE4B, PDE4C etc) and different drugs effect different subtypes differently.

Ibudilast is used as a daily drug therapy for asthma in Japan and is being studied as a therapy for Multiple Sclerosis (MS) in the US.

Roflumilast is sold by Astra Zeneca as Daxas/Daliresp but at a high dose of 500mcg to treat flare ups of COPD (Chronic Obstructive Pulmonary Disease) it does cause troubling side effects, but it reduces your chance of dying from COPD.

The cognitive dose used in research is 100mcg. Higher doses had no cognitive/sensory gating benefit.

Further investigation of the ADHD drug Guanfacine should be made, because some of the people who benefit from a PDE4 inhibitor might get a similar effect from Guanfacine. People with Pitt Hopkins would not be in this category. A person with Asperger’s and impaired sensory dating should respond to Guanfacine, a cheap drug.

At the end of the day, choice of therapy will come down to side effects and cost. In the US, Roflumilast is expensive ($330), seven times more expensive than in some other countries; in the UK the price of the same 30 tablets is $50. One pack would be enough for 5 months at the suggested dose.

Trajectories of Intellectual Development in Autism

Tracking IQ over a 3-4 year period, in 4 sub-groups of 2-8 year olds

Today’s post is about trajectories of intellectual development in autism, which I have to come to believe is the most important aspect of autism and certainly helps you understand where your type of autism fits in.

As regular readers may recall average IQ = 100 and the IQ scale fits a bell-curve, so most (68%) people have an IQ within the range 85-115.  2.1% of the general population have an IQ less than 70, which is the cut off for a diagnosis of MR/ID (Intellectual Disability).

There are special tests to measure IQ in non-verbal people and IQ testing is matched to your age; so the older a child gets the more there is expected from them in the test.

I do wonder how you can fairly test the IQ of a 2 year old with severe autism. So I think some testing in very young children may substantially underestimate IQ. 

A study was recently published taking data from the Autism Phenome Project run by UC Davies.

What will my child's future hold? phenotypes of intellectual development in 2-8-year-olds with autism spectrum disorder.

Even though the sample size is only a hundred, what makes it interesting is that it is a longitudinal study, meaning they collect data from the same kids over a period of many years.

Welcome to the Autism Phenome Project

They fitted data from the hundred kids into four groups and then took the average IQs within each group. The kids had IQ measured twice, not at exactly the same ages, but about 4 years apart. (The youngest at T1 was two years old and the oldest at T2 was eight)

I used their data and apply my interpretation. I do not think they made the most of their own data.

So the first group (black) are the Asperger’s kids who were 22% of the sample group.  This group started out at 2-3 years old with IQ just under 100 but in the next 4 years they raised their cognition at an above average rate, so that average IQ rose to 110. Not bad going.   Average IQ in the general population is 100.

Classic autism is the red group at the bottom and as expected their IQ starts out low and gets worse, because they add skills at a lower rate then NT kids, so even though they learn, their measured IQ falls. This group was 26%.  Even though the sample is very small at 100, this is close to my estimate of classic autism (SDA) being about 30% of all autism. In some countries you have to measure IQ to access services. Our behavioral consultant was not a fan, because the parents get upset when IQ goes down over time, so we never measured IQ. The red line is even lower than I had expected.

The green line I called responsive autism, because even though IQ is low it does not fall during the 4 years period where it was measured. This group account for 18% of the total. These children are acquiring new skills at a fair rate.

The good news is the blue line; in that large sub-group of 35%, the kids had some kind of “dysmaturation” at time 1, allowing them to make rapid cognitive improvement in the 4 years after their diagnosis (Time 1). They have gone from a technical definition of MR/ID to getting close to average IQ.

It would be great to see what happens at Time 3. I suppose if we wait 4 years we may find out.

I think some of the 35% (blue line) likely did not perform to their full ability at the first test (at time 1), for which there are numerous reasons, not liking/being familiar with the tester being an obvious one.  Based on other sources from this blog, I think it is about 15% of autism cases that make such a dramatic improvement to the age of eight.

In the above study the type of intervention chosen by parents (how many hours of ABA, speech therapy etc) had no correlation with IQ improvement from Time 1 to Time 2. It is your biology that matters most and to tweak that you need a little help from chemistry, as some regular readers have discovered. 

Counter Argument 

There is a alternative view that IQ is not important in ensuring favorable outcomes in autism; this does sound rather odd. It is a view put forward not just by the small, but vocal, group with Asperger's promoting their "neurodiversity" ideas, but also some well paid researchers. In my chart above I used Asperger's for the black line representing the people with average IQ. In the actual paper they do not call it Asperger's.

Intelligence scores do not predict success for autistic adults 

This is a very recent, rather light weight, article and would be much better if titled "Intelligence scores do not predict success for Aspies."   

Aspies do indeed share some biological problems with people with severe autism, but their daily life problems are much closer to those faced by people with Schizophrenia or Bipolar. A good example is suicide, where it is extremely common in bipolar, said to be 10% (as cause of death) in schizophrenia and ten times the "normal" level in Asperger's.  In severe autism the suicide rate is zero, they may have accidents but do not try to kill themselves.

In someone with Asperger's and an IQ of 120, boosting their IQ to 140 will likely not help them; it would just make them feel more different. In a ten year old with severe autism and an IQ of 50, a child who cannot figure out which way round to put on his T shirt, cannot tie his shoelaces and does not understand why you need to cut your finger nails, a boost in IQ to 80 would be transformative. 

The education of people with severe autism focuses on adaptive behavior, or life skills. These are key skills for semi-independent living. These are skills that children of average IQ just pick up from observing the people around them. People with impaired cognitive function cannot just pick up these skills, they need to be taught (again and again and again).  I spent three years trying to teach prepositions to my son Monty to the age of eight, using a special computer program created for other people with exactly the same difficulty. Once I started addressing cognitive function, with Bumetanide, from the age of 9, Monty figured out prepositions all by himself, without any teaching. I never even bothered to use the remaining language teaching software that I had paid $1,500 for, as a bundle, when he was four years old.  It is still sitting unopened on the shelf. 

Macrolide Antibiotics for Some Autism? Or better still, Azithromycin analogue CSY0073, or just Nystatin?

Magical Poland

Today’s post is about yet another reason why some people with autism might have a positive behavioral response while on antibiotics. Today it is the turn of macrolide-type antibiotics, which have proven immunomodulatory effects.

To get the immunomodulatory benefits, without worsening antibiotic resistance, a neat solution called CSY0073 is coming. Nystatin is another possibility.

One of the best papers happens to come from a pair of researchers from Lodz (Łódź, pronounced “Wudge”) in Poland. This blog has many Polish readers. 

I was recently helping my son, Monty aged 14 with ASD, with his geography presentation on Poland.  I used to travel quite a lot to Poland and I am familiar with its turbulent history. So today’s picture above is actually from Monty’s PowerPoint presentation on Poland. As musical backing, we added one of Chopin’s Polonaises, since Monty is the piano man and Chopin was born in Poland. Polonaise (Polonez) is the name of a type of Polish dance and yes, Monty did dance to the music for his classmates.

The Germans and the Russians have changed the make-up of Poland profoundly and someone has produced the animated map above to illustrate this (it should play automatically). Lodz used to be a textile city with a population one third Jewish, who were later exterminated.  Lviv (Lwów), another large and once Polish city, also had a large Jewish population which the Germans exterminated. Then the Soviets gave the then Lwów (Lviv) to Ukraine and deported the Polish population.  The Soviets gave the German city of Breslau to Poland and it became Wrocław; most Germans were deported and many Poles from Lviv were relocated there.

Gdansk (Danzig) changed hands as well and, as Monty informed his class, they even had their own currency. Few outside Poland will recall Gdansk was home to Lech Wałęsa and his Solidarity Movement.  Monty’s elder brother knows about Solidarity and Katyn (see below) and we agreed Lech will for sure not be on Vladimir Putin’s Christmas list. 

A very charismatic older Pole in Warsaw once told me “the Russians were our brothers, your friends you can chose”. Having also been to Russia many times in the early 1990s, just after the collapse of the Soviet Union, I should point out there are plenty of nice Russians too. An old Russian former naval commander in St Petersburg  once told me how his father always kept a packed bag by the front door at home, in case the NKVD (Stalin’s secret police) came knocking at the door in the middle of the night. Half a million Russians were taken during Stalin’s purges 1936-8. In 1940 the same NKVD perpetrated the Katyn massacre, when 22,000 Polish army officers, policemen and “intellectuals” were killed.  In a sad twist of fate in 2010 a Tupolev plane carrying the Polish president, senior politicians, senior army officers and other leading Poles to a commemoration of the Katyn massacre crashed in very bad weather trying to land at Smolensk.  The cockpit voice recorder showed that the crew were too intimidated by the President to divert the plane and be late for the ceremony, so they all died.  History repeated itself.

The Poles and Russians do share traumatic histories and many like drinking too much vodka. As Monty’s classmates learned, “vodka" is one diminutive form of the Slavic word voda (water). They like diminutives and you can even make your own.  The Russians have a diminutive of vodka, водочка (vodochka).

Back to science …

Macrolide Antibiotics 

Macrolide antibiotics are widely used across the world, the most popular ones are:-

• Azithromycin
• Clarithromycin
• Erythromycin
• Fidaxomicin
• Telithromycin

As readers will know, you normally take an antibiotic short term to treat a bacterial infection.

It was discovered that this class of antibiotic also has immunomodulatory and anti-inflammatory properties.  They became used long-term to treat conditions like cystic fibrosis, COPD (Chronic Oppressive Pulmonary Disease) and sometimes even asthma.

The problem is so-called “population antimicrobial resistance” associated with chronic macrolide use, which means these antibiotics can stop working for everyone else.

The good news is that not all macrolides have antibiotic properties and analogues (slightly different version) of both azithromycin and erythromycin are being developed to give the immunomodulatory and anti-inflammatory properties, without risking antimicrobial resistance.

Of course what will happen is that the new drugs will be far more expensive than the old ones and so the old ones will continue to be used. Such is the world.

So first we will review the science showing these special properties of Azithromycin, which can apparently work wonders for some people with autism plus allergy, although the research below talks about other inflammatory diseases.

Here is the paper from Poland:-

Immunomodulatory and anti-inflammatory properties of macrolides

 Macrolides are a group of antibiotics whose activity is ascribable to the presence of the macrolide ring, to which one or more deoxy sugars may be attached. Two properties are inherent in this group of antibiotics, the immunomodulatory and the anti-inflammatory actions, ensuring great efficacy in a wide spectrum of infections. Macrolides demonstrate several immunomodulatory activities both in vitro and in vivo. They can down-regulate prolonged inflammation, increase mucus clearance, prevent the formation of bacterial biofilm and either enhance or reduce activation of the immune system. According to given properties and exceptional effects on bacterial phatogens, the macrolide antimicrobial agents have been found to serve a unique role in the management of chronic airway disorders, including diffuse pan bronchiolitis, cystic fibrosis and chronic obstructive pulmonary disease. Use of macrolides can result in clinical improvement in patients with severe, chronic inflammatory airway diseases, improving their spirometry indicators, gas exchange and overall quality of life. 

Anti-inflammatory and immunomodulatory effects Macrolides have a direct antimicrobial effect but more importantly, also modulate many components of the immune response. Because of this anti-inflammatory or immune modulating effect, macrolide antibiotics have been widely used as a maintenance treatment for various chronic inflammatory airway diseases [1]. Interest in the immunomodulatory effects of macrolides began with showing that in patients with bronchial asthma, requiring glucocorticoids administration, application of macrolide antibiotics allowed for reducing steroids dose [6]. This phenomenon is known as ‘sparing effect’.

After more than 30 years, macrolides still hold a vital place in our therapeutic armamentarium. They possess immunomodulatory and anti-inflammatory actions extending their antibacterial activity. Indeed, they are able to suppress the “cytokine storm” of inflammation and confer an additional clinical benefit through their immunomodulatory properties. The majority of cells, involved in both the innate and adaptive immune responses, are influenced when macrolide antibiotics are administered.

Suppressing a cytokine storm is not easy. Atorvastatin can also do this.

Low-dose, long-term macrolide therapy in asthma: An overview

Azithromycin as an immunomodulator

In addition to their antimicrobial properties, there are in vitro and animal data on the immunomodulatory or anti-inflammatory effects of macrolides.¹ Effects in humans were initially reported in the treatment of diffuse panbronchiolitis, in which macrolides are associated with improved lung function and prognosis based largely on non-controlled trial data and retrospective studies.¹ In cystic fibrosis, treatment for six months is associated with improved respiratory function and reduced respiratory exacerbations.¹¹ Azithromycin produced a small increase in lung function (mean 8.8%) at seven months in patients treated for bronchiolitis obliterans syndrome after lung transplant,¹² but was no different compared to placebo for bronchiolitis obliterans syndrome after haematopoetic stem cell transplant.¹³

Azithromycin and other macrolides have also been proposed for use in sepsis and epidemic respiratory viral infections to prevent cytokine storm.¹ It has been used for various respiratory and non-respiratory inflammatory conditions. However, this use has been controversial due to limited direct clinical evidence for many conditions, and concerns about increased antimicrobial resistance.^1,14 New non-antibiotic macrolides may provide immunomodulatory benefits without contributing to antimicrobial resistance.¹⁴

Risks of population antimicrobial resistance associated with chronic macrolide use for inflammatory airway diseases.

Macrolide antibiotics have established efficacy in the management of cystic fibrosis and diffuse panbronchiolitis-uncommon lung diseases with substantial morbidity and the potential for rapid progression to death. Emerging evidence suggests benefits of maintenance macrolide treatment in more indolent respiratory diseases including chronic obstructive pulmonary disease and non-cystic fibrosis bronchiectasis. In view of the greater patient population affected by these disorders (and potential for macrolide use to spread to disorders such as chronic cough), widespread use of macrolides, particularly azithromycin, has the potential to substantially influence antimicrobial resistance rates of a range of respiratory microbes. In this Personal View, I explore theories around population (rather than patient) macrolide resistance, appraise evidence linking macrolide use with development of resistance, and highlight the risks posed by injudicious broadening of their use, particularly of azithromycin. These risks are weighed against the potential benefits of macrolides in less aggressive inflammatory airway disorders. A far-sighted approach to maintenance macrolide use in non-cystic fibrosis inflammatory airway diseases is needed, which minimises risks of adversely affecting community macrolide resistance: combining preferential use of erythromycin and restriction of macrolide use to those patients at greatest risk represents an appropriately cautious management approach.  

Changes in macrolide resistance rates since the introduction of long-acting macrolides Although erythromycin has been used since the 1950s, rates of macrolide resistance among respiratory pathogens were consistently low worldwide until the late 1980s. Since then, macrolide resistance rates have risen sharply, coincident with the introduction of long acting macrolides, particularly azithromycin (see later) but also clarithromycin.

  Conclusions The development of novel, non-antibiotic macrolides with anti-inflammatory properties, including EM703107 and CSY0073, holds great promise for delivering the benefits of macrolide treatment without the associated risks of antimicrobial resistance in the future. Until then, use of long-term macrolide antibiotics to treat respiratory disorders must be prudent. The benefits shown with maintenance macrolides so far have been modest in COPD and non-cystic fibrosis bronchiectasis, and their use should be limited to patients with more difficult (and otherwise optimally managed) disease. For non-cystic fibrosis inflammatory airways diseases, combining the preferential use of erythromycin along with restriction of macrolide use to only those likely to derive the greatest benefit represents a clinically appropriate, and ecologically responsible, management approach.

Azithromycin analogue CSY0073 attenuates lung inflammation induced by LPS challenge.

CONCLUSIONS AND IMPLICATIONS:

Unlike azithromycin, CSY0073 had no antibacterial effects but it did have a similar anti-inflammatory profile to that of azithromycin. Hence, CSY0073 may have potential as a long-term treatment for patients with chronic lung diseases.

  

EMA grants orphan status to Synovo anti-inflammatory for Cystic Fibrosis

Tuebingen, Germany: – German-based pharmaceutical discovery company Synovo GmbH today announced that the European Medicines Agency (EMA) has granted its anti-inflammatory drug with orphan (rare disease) status as a treatment for Cystic Fibrosis. Synovo refers to its candidate as CSY0073.

CSY0073 has been adjudged to provide an alternative to anti-inflammatory therapies that are also anti-bacterial, thus potentially contributing to a reduction in selection for antibiotic resistance. The drug is a novel compound that reduces inflammation and prevents recruitment of excess immune cells to diseased tissues. It is a non-antibacterial analog of the well-known antibiotic azithromycin, that is extensively used in many diseases of the lungs including Cystic Fibrosis.

  

Conclusion

We saw in earlier posts why beta lactam antibiotics might benefit some people with autism.

We came across the GLT-1 (EAAT2) transporter, the principal transporter that clears the excitatory neurotransmitter glutamate from the extracellular space at synapses in the central nervous system. Glutamate clearance is necessary for proper synaptic activation and to prevent neuronal damage from excessive activation of glutamate receptors. EAAT2 is responsible for over 90% of glutamate reuptake within the brain. Beta lactam antibiotics, like penicillin, upregulate EAAT2/GLT-1 and so reduce glutamate.

I suggested that people with autism who improve on penicillin types antibiotics should get a similar effect from riluzole, which is now a generic drug.

People whose autism benefits while on macrolide antibiotics are benefitting from its immunomodulatory effects.

People with severe allergy and autism are likely to respond to long term moderate dose of macrolides. 

The problem of long term use of any antibiotic is that it contributes to the decline in its effectiveness for everyone else.

Some DAN-type doctors apparently do apparently give one year prescriptions for beta lactams.   I think these people likely should be on riluzole.

Some mainstream doctors prescribe moderate dose macrolide antibiotics long term to treat people with “over-active” immune responses. It appears many people with cystic fibrosis are treated long term with macrolide antibiotics.

I am informed that some people with autism and “over-active” immune responses respond very well behaviorally to long term use of macrolide antibiotics.

The best solution in the long run is for people to use non-antibiotic macrolides like CSY0073, from Synovo. If it turns to be very expensive, people will just use azithromycin.

In the meantime note there are other non-antibiotic macrolides sitting in the pharmacy. 

·        Nystatin is a non-antibiotic macrolide. As we know, DAN-type doctors widely prescribe Nystatin to treat “candida overgrowth” in autism. It is also a potassium channel (Kv1.3) blocker. 

·        The drugs  tacrolimus, pimecrolimus, and sirolimus, which are used as immunomodulators, are also non-antibiotic macrolides.

There look to be many interesting possibilities for those with autism and allergy/mast cell activation/ulcerative colitis/asthma etc. 

I wonder if the people with autism and allergy who respond to long-term Azithromycin use would see the same benefit from Nystatin?

Long term use of antibiotics will disrupt the gut microbiome, i.e. kill the good bacteria.  People should be aware of this and that in minimizing one problem, they may create another one. The non-antibiotic options are clearly best. If you have cystic fibrosis the advantages of an antibiotic clearly outweigh the disadvantages. 

Under-expression (Haploinsufficiency) of ARID1B in Autism and Corpus Callosum Abnormalities

People keep telling me that my blog is too complicated; compared to the literature it really is not. If your child has a disabling condition you really should be willing to invest all the time needed to learn about it, rather than be a passive bystander.

I think you can investigate even complex sounding genetic disorders without being an expert, which is what happens in today’s post.  

Are there 20,000 types of jeans?

As readers may recall, humans only have about 20,000 genes, far less than originally was thought. Each gene provides the instructions to make one thing, usually a protein.

For the great majority of genes we have two copies, one from Mum and one from Dad. Mitochondrial genes all come from Mum.

These genes are stored on chromosomes (like recipe books).

For 22 of these recipe books you have two copies, so if one page got damaged at least you have an undamaged version from the other book.

The 23rd pair of books is special because while females have two copies, males do not. This is the X chromosome and if a male has a problem on any page in this little book, he has a big problem, while his sister has less of a problem, because she has a spare copy. The male has a Y chromosome in place of a second copy of X. 

Examples of problems on the X chromosome:-

·        The MECP2 gene is on the X chromosome and when there is one working copy and one mutated version you have Rett syndrome and you must be female. If you were male with one mutated version you cannot survive.

·        In Fragile X syndrome a problem with the FMR1 gene means not enough not enough fragile X mental retardation protein (FMRP), which is required for normal development of the connection between neurons. Females would normally have a clean spare copy of the FMR1 gene and so show much less severe symptoms that a male with Fragile X.

Problems on chromosomes 1 to 22:-

If you have a problem in the first 22 chromosomes (recipe books), boys and girls are equal. If one page got damaged you can always look up the recipe in the other book.

In case one gene got mutated but the other copy is fine, things can work out just fine, in which case it is called haplosufficiency. You get to make enough of that protein.

In some cases you really need to use that recipe a lot; that particular protein is in big demand. One copy of that gene just is not enough. This is called  haploinsufficiency.

In most cases when the gene has a problem, it just fails to produce the intended protein. In some cases it actually produces a mutated protein, which can be worse than no protein. 

Pitt Hopkins

In Pitt Hopkins Syndrome there is a problem on chromosome 18, where you find the TCF4 gene. Not enough expression of TCF4 means not enough Transcription Factor 4;  this is an example of haploinsufficiency.

Now the reason why these rare conditions are important to many other people is that they not only affect people who happened to have a random mutation and hence a severe deficit of the protein; moderately reduced transcription of this gene, for any reason, can also result in troubling symptoms.

So in the case of the Pitt Hopkins and the gene TCF4, as was pointed out to me recently, reduced expression is a feature of some MR/ID and indeed schizophrenia. 

The Intellectual Disability and Schizophrenia Associated Transcription Factor TCF4 Is Regulated by Neuronal Activity and Protein Kinase A 

Instead of just a tiny number of people with Pitt Hopkins, you can see that upregulating TCF4 expression could help a lot of people.

It appears that people with Pitt Hopkins have a “clean copy” of TCF4, so it is just a case of making it work a little harder. There are ways being researched to achieve just that.

I suspect people with schizophrenia have two “clean copies” of TCF4, but for some reason have a deficiency of the protein encoded by it.

In the above paper it was shown that Protein Kinase A (PKA) plays a key role in regulating what your TCF4 gene is producing.

We have come across PKA before in this blog and we know that in regressive autism there can be a deficit of PKA. There is also PKB and PKC. All three are very important, but complicated. 

Brain Region–Specific Decrease in the Activity and Expression of Protein Kinase A in the Frontal Cortex of Regressive Autism

Without going into all the details you can see that if someone with Pitt Hopkins has a lack of PKA, like those with regressive autism, then he will struggle to make the most of his good copy of the gene TCF4.

It all gets very complicated, but PKA is controlled by something called cAMP. In turn cAMP is controlled by PDE. PDE4 is known to be disturbed in the brains of some people with autism.

It appears that you can activate PKA with a PDE4 inhibitor. The long established Japanese asthma drug Ibudilast is such a PDE4 inhibitor. At least one reader of this blog uses Ibudilast long term.

PDE4 inhibitor, roflumilast protects cardiomyocytes against NO-induced apoptosis via activation of PKA and Epac dual pathways

PDE4 inhibitors have been explored to treat various neurological conditions like schizophrenia.

PDE4 as a target for cognition enhancement

So logically if you feed a PDE4 inhibitor to a Pitt Hopkins mouse, you might expect something good to happen. There now is such a mouse model.

I think I could keep that mouse quite busy. 

The point being you do not have to figure things out 100%, before starting to see what you have in your drug library might be truly beneficial.  

Some of the things in the drug library are actually in the kitchen cupboard, as we have already seen. 

Protein Kinase A

Protein kinase A (PKA) is something that is both complicated and important.

The effects of PKA activation vary with cell type.

PKA has always been considered important in formation of a memory.  Formation of a normal memory is highly sensitive to PKA levels; too much is bad and too little is bad.

ARID1B in Autism and Corpus Callosum Abnormalities

I don’t think anyone has set up a research foundation for agenesis of the Corpus Callosum (ACC), perhaps they should. 

There was a post on this a while back, prompted by meeting someone whose son has this condition. 

Agenesis of the Corpus Callosum

The Corpus Callosum is just a fancy name for what joins the two sides of the brain together. Agenesis of the Corpus Callosum (ACC) is what they call it when there is a complete or partial absence of the corpus callosum.

ACC is we are told a very rare condition, but clearly smaller corpus callosum variations are a key part of some autism. 

For example, in Pitt Hopkins a small corpus callosum is typical.

An estimated 7 percent of children with autism and macrocephaly (big heads) carry a PTEN mutation. This is associated with an enlarged corpus callosum. 

PTEN is an autism gene, but it is more usually thought of as a tumor suppressor, making it a cancer gene. In older people, losing PTEN appears to be often a first step to developing cancer; up to 70% of men with prostate cancer are estimated to have lost a copy of the PTEN gene at the time of diagnosis  (https://www.ncbi.nlm.nih.gov/pubmed/16079851). 

PTEN is interesting because too little can allow cancer to develop, but too much may eventually result in type 2 diabetes. So, as always, it is a balance. 

PTEN upregulation may explain the development of insulin resistance and type 2 diabetes with high dose statins. 

Evidently from the comments in this blog, regarding tumors/cancers, people with autism are likely shifted towards the direction of lacking tumor suppressing proteins. The exception would be those born very small, or with small heads. 

ARID1B gene

ARID1B is another tumor suppressing gene, like PTEN, and like PTEN it is also an autism gene.

What I found interesting was the link between ARID1B and corpus callosum anomalies. 

ARID1B mutations are the major genetic cause of corpus callosum anomalies in patients with intellectual disability  

Corpus callosum abnormalities, intellectual disability, speech impairment, and autism inpatients with haploinsufficiency of ARID1B

Corpus callosum abnormalities are common brain malformations with a wide clinical spectrum ranging from severe intellectual disability to normal cognitive function. The etiology is expected to be genetic in as much as 30–50% of the cases, but the underlying genetic cause remains unknown in the majority of cases.

Additional functional studies including a systematic search for ARID1B target genes may show how haploinsufficiency of ARID1B predispose to CC defects and to an array of cognitive defects, including severe speech defects

Several readers of this blog have highlighted a recent study:-  

Breakthrough research suggests potential treatment for autism, intellectual disability 

We showed that cognitive and social deficits induced by an Arid1b mutation in mice are reversed by pharmacological treatment with a GABA receptor modulating drug. And, now we have a designer mouse that can be used for future studies." 

The full study:-

Arid1b haploinsufficiency disrupts cortical interneuron development and mouse behavior

Clonazepam also reversed the reduced time spent in the center and reduced moving distance displayed by Arid1b-mutant mice in the open field test (Fig. 7c,d and Supplementary Fig. 14c). However, depression measures, using the forced swim test and the tail suspension test, showed no reversible effect of clonazepam in Arid1b+/− mice compared with controls (Fig. 7e,f). Our results show that clonazepam rescues impaired recognition, social memory, and elevated anxiety in Arid1b+/− mice. 

Our mouse model effectively mirrors the behavioral characteristics of intellectual disability and ASD. Arid1b+/− and Arid1bconditional-knockout mice displayed impaired spatial learning, recognition memory, and reference memory. Open field and social behavior tests also revealed decreased social interaction in the mice. Mice with mutations in genes encoding Smarca2 and Actl6b, other subunits of the BAF complex, have severe defects in social interaction and long-term memory35. Thus, this chromatin remodeling complex may provide a cellular and molecular platform for normal intellectual and social behavior. In addition, Arid1b+/− mice showed heightened levels of anxiety- and depression-related behaviors, which are common symptoms of ASD36. 

For people with intellectual disability, the prevalence of anxiety disorders has likewise been shown to be much higher. This may be due to reduced cognitive function and increased vulnerability to environmental demands. Communication difficulties may also make it more difficult for people with cognitive disabilities to deal with anxiety or fear. ARID1B haploinsufficiency may be responsible for multiple facets of characteristic ASD behaviors. Other isoforms of Arid1b that are not affected by the Arid1b mutation could exist in the mouse line. Additionally, it is possible that the genetic background for the mouse line may impact the effect of Arid1b haploinsufficiency. Thus it is important to consider allele specificity, genetic backgrounds, and knockout strategies for comparing phenotypes of other Arid1bhaploinsufficiency models.  

GABA allosteric modulators, including clonazepam, a benzodiazepine, have been used to treat seizures and anxiety. We found that clonazepam injection rescued deficits in object and social recognition and anxiety in Arid1b+/− mice. These results suggest that treatment with a benzodiazepine could be a potential pharmacological intervention for symptoms of ASD. Furthermore, our results suggest that pharmacological manipulation of GABA signaling is a potential treatment strategy for cognitive and social dysfunctions in ASD- or intellectual disability-associated disorders due to mutations in chromatin remodeling genes.  

ACC Research Foundation

If there actually was an ACC Research Foundation, they could explore whether clonazepam was therapeutic in children who have Arid1b haploinsufficiency.

While they are at it, they might want to look into Hereditary Motor and Sensory Neuropathy with agenesis of the corpus callosum (HMSN/ACC), this is caused by mutations in the potassium-chloride co-transporter 3 (SLC12A6/KCC3) gene. This I stumbled upon a long time ago, when trying to upregulate KCC2, which causes elevated intracellular chloride in many people with autism and likely many with Down Syndrome.

KCC2 is usually associated with neuropathic pain and now we see that so is KCC3. Odd reaction to pain is a well known feature of autism. The rather ill-defined condition of fibromyalgia seems common in female relatives of those with autism and I do not think this is just a coincidence. 

The interesting thing is that the research shows you can potentially upregulate KCC3 with curcumin. 

Transit Defect of Potassium-Chloride Co-transporter 3 Is a Major Pathogenic Mechanism in Hereditary Motor and Sensory Neuropathy with Agenesis of the Corpus Callosum

HMSN/ACC is a severe and progressive neurodegenerative disease that exhibits an early onset of symptoms. Signs of HMSN/ACC, such as hypotonia and delays in motor development skills, are noticed before 1 year of age. However, the motor abilities of patients progress slowly to 4–6 years of age, and these children are able to stand and walk with some help. This is followed by a motor deterioration that generally renders affected subjects wheelchair-dependent by adolescence. 

Accordingly, we found that curcumin relieved the ER retention of dimerized R207C in mammalian cultured cells. A diet enriched in curcumin may therefore be beneficial for the relief or delay of some of the HMSN/ACC symptoms in patients bearing the R207C mutation, including the Turkish patient described in this study (as patient has not yet reached puberty).

KCC3 defects also cause the very similar Andermann syndrome also known as agenesis of corpus callosum with neuronopathy (ACCPN).

KCC3 defects are associated with epilepsy.

My question was can you have KCC3 under-expression with partial ACC, epilepsy but no peripheral neuropathy? If this was likely, then upregulating KCC3 with curcumin might help.

The gene for KCC3 is located at chromosome 15q14. Based on my “logic of associations”, if you have ACC and epilepsy you should consider KCC3 under-expression.

I did suggest to my former classmate whose son has partial ACC and epilepsy, but no neuropathy, that it might be worth trying some curcumin. Since his son is already on anti-epileptic drugs (AEDs) my suggested effect to look for was improved cognitive function.

6 months later it does indeed, apparently, improve cognitive function.  Of course this does not establish that upregulating KCC3 had anything to do with it. It is nonetheless a nice story and another parent has realized that you can change things for the better, in spite of what neurology currently says. 

The question now is can you have both ARID1B under-expression and KCC3 under-expression, in which case you would add some clonazepam, based on the latest research. At this point you should of course go and talk to your neurologist, rather than read my blog and that was my recommendation. 

Partial agenesis of the corpus callosum in a patient with juvenile myoclonic epilepsy

We describe a patient who presented at our epilepsy-monitoring unit with myoclonic jerks, and was diagnosed with juvenile myoclonic epilepsy (JME). Imaging of his brain revealed partial agenesis of the corpus callosum (ACC). We discuss the known genetic basis of both JME and ACC, as well as the role of the corpus callosum (CC) in primary generalized epilepsy. Both JME and ACC are associated with gene loci on chromosome 15q14. Structural brain abnormalities other than ACC, such as atrophy of the corpus callosum have been reported in patients with JME. ACC has been associated with seizures, suggesting an anti-epileptogenic role of the corpus callosum

Conclusion

If you have a biological diagnosis you are one big step closer to finding a therapy. Even if you have a diagnosis like partial Agenesis of the Corpus Callosum (ACC), you can go one step further and ask why. You have a 50% chance of being able to find out a specific gene that is the cause. If you know with certainty which gene is the originator of the problem, you know a lot.  I think you are then two big steps closer to a therapy.

In the case of Rett Syndrome, a really good website is run by their research foundation (Rett Syndrome Research Trust). They look like they mean business. 

https://reverserett.org/cure/

If you look at the above site you might be left wondering why the much larger and better financed autism organizations look so amateur by comparison.  The big difference is that Rett Syndrome is a biological diagnosis and autism is not. In many ways calling autism a spectrum is not helpful, as the originators of the ASD concept are beginning to realize.  The precise biological dysfunctions are what matter and lumping together hundreds of miscellaneous brain dysfunctions into a pile labelled ASD may not be so clever, in fact I would call it primitive.