Epsom salts, Autism and Hypokalemic Sensory Overload

Early on in this blog I wrote about a supposedly rare condition, where somebody suffers from sensory overload, usually from sound, but it could be light or even smell.  That condition has fancy sounding name, Hypokalemic Sensory Overload.  The cure is very simple, just to give oral potassium and within 20 minutes there is a full recovery.  Here is one research study.

 

I felt it odd that nobody had compared this to sensory overload in autism.  I did my own experiment at home and found to my surprise that sensory overload in autism could also be treated with oral potassium.

In the last few weeks I received two very thoughtful comments on this blog, from adult sufferers who have found the same remedy as I have.  So at least I am no longer in a minority of one.

The interesting thing about potassium in the human body is that it relies on another electrolyte, magnesium.  Without sufficient magnesium, the body cannot maintain an adequate level of potassium.  This is why supplements normally contain both potassium and magnesium.  A problem with both potassium and magnesium is that they very easily upset the stomach, indeed some laxatives are based on magnesium.

Epsom salts

I have noted that the long list of autism interventions used in the US, frequently includes having a bath in Epsom salts.  Epsom salts are named after a town near London, England, from which they were originally mined.  Epsom salts are just magnesium sulphate (MgSO4).

In the “biomedical” community it is proposed that magnesium does great things for autism and/or sulphur does.

The sulphur part at least has a scientific explanation.  It was long ago shown that there is an apparent abnormality in the sulphur metabolism in autism. 

In effect there is greater loss than normal of sulphur in the urine, resulting in lower plasma levels than in typical people.

So people are dipping their kids in Epsom salts on that basis that either the magnesium or the sulphur will do some good, not sure of which.

Interestingly, on the web, I found one mother writing about the Epsom salts baths she gives her child; she says she know when it is time for another one, where her child starts to cover her ears (sound sensory overload).

Trans-dermal Magnesium

Since magnesium supplements are in-effect laxatives, other ways have been sought to administer this electrolyte.  There are several transdermal creams and sprays that do indeed seem to work, but they can irritate the skin.  Interestingly, also on the web, some autistic adults talk about using such supplements and benefiting. 
 

Making the Connection

Well I hope this is all obvious to you, at least one of the things that is going on is an ion channel disease, the result of which is sensory overload in autism.  By chance, some people have stumbled upon magnesium supplementation as a therapy.  The extra magnesium is making whatever potassium there is in that person’s diet more effective, and hence reducing their symptoms.  Since the condition is actually Hypokalemic Sensory Overload, they would do even better to add some extra potassium as well.

The sulphur part may, or may not be, a red herring.  Sadly there are many of them in autism.

Conclusion

I have completed this part of my autism investigation.  If you want to treat autistic sensory overload, that seems to affect almost all people with ASD and most with ADHD, the options are:-

1.     Reduce the body’s daily loss of potassium and magnesium, with a potassium sparing diuretic, like Spironolactone

2.     Increase consumption of potassium and magnesium in diet.  Bananas, oranges and kiwis are rich in potassium, for example.

3.     Use small doses of oral potassium and magnesium supplements throughout the day

4.     Use expensive transdermal magnesium treatments.  Nobody seems to make a potassium version.

5.     Take a soak in the bath with an added cup of Epsom salts.

There should be a second reason to try option (1).  For entirely unrelated reasons, this drug is proposed to help in autism due to its secondary anti-inflammatory and hormonal effects.
Spironolactone might be a desirable immunologic and hormonal intervention in autism spectrum disorders

 I have to say that, having done my field research, I will be sticking with (2), (3) and the occasional (5)

 

The therapeutic effects of apigenin are pleiotropic. Is its effect on sound sensitivity mediated via potassium channels?

Chamomile, a good source of Apigenin

 

Today we return to flavonoids, those healthy chemicals found in fruits, vegetables, flowers etc.

In particular, the focus is on apigenin, found in things like chamomile, parsley, oregano and in medicinal herbs like Bacopa monnieri.

 

Why the interest in Apigenin?

I did discover a while back that sound sensitivity in some autism responds almost immediately to low dose Ponstan (Mefenamic acid), which is a widely used as a pain reliever.

I was recently informed by a reader who responds well to Ponstan (250mg once a day) that he gets exactly the same relief from sound sensitivity from taking the flavonoid Apigenin (500mg a day). 

Both Ponstan and Apigenin are OTC in many countries. In countries like Greece Ponstan is extremely cheap.  In the US Ponstan is very expensive and supplements tend to be cheap. 

For adults with sound sensitivity drinking chamomile tea might be a good source of 50 mg of Apigenin (you would need about 20g of chamomile flowers). Using the dried flowers likely gives better results than ready-made tea bags.

 

Pleiotropic effects

Both Ponstan and apigenin have numerous beneficial effects.  I noted in my earlier posts on Ponstan that it seems to offer protection from Alzheimer’s. Perhaps surprisingly, people who take Ponstan are much less likely to develop Alzheimer’s. Nobody has studied apigenin in human Alzheimer’s, but in animal studies, apigenin has been shown to improve cognitive function, reduce amyloid plaques, and protect neurons from damage.

 

Other Flavonoids used in Autism

Dr Theoharides wrote a lot about flavonoids to treat autism and mast cell disorders.  His product Neuroprotek is a combination of three flavonoids: luteolin, quercetin, and rutin, which are found in plants such as celery, onions, and citrus fruits.

Epigallocatechin gallate (EGCG) is a flavonoid found in green tea. The Spanish like doing research on EGCG and they believe it has promise as an autism therapy. One of the effects is to modify the gut microbiome. EGCG has also been shown to accumulates in mitochondria making it an interesting therapeutic candidate for neurodegenerative diseases involving neuronal apoptosis triggered by mitochondrial oxidative stress. It has been studied in Down syndrome, Rett syndrome and some other models of autism.

 

A very detailed overview is available in the paper below:-

The Emerging Role of Flavonoids in Autism Spectrum Disorder: A Systematic Review

Although autism spectrum disorder (ASD) is a multifaceted neurodevelopmental syndrome, accumulating evidence indicates that oxidative stress and inflammation are common features of ASD. Flavonoids, one of the largest and best-investigated classes of plant-derived compounds, are known to exert antioxidant, anti-inflammatory, and neuroprotective effects. This review used a systematic search process to assess the available evidence on the effect of flavonoids on ASD. A comprehensive literature search was carried out in PubMed, Scopus, and Web of Science databases following the PRISMA guidelines. A total of 17 preclinical studies and 4 clinical investigations met our inclusion criteria and were included in the final review. Most findings from animal studies suggest that treatment with flavonoids improves oxidative stress parameters, reduces inflammatory mediators, and promotes pro-neurogenic effects. These studies also showed that flavonoids ameliorate the core symptoms of ASD, such as social deficits, repetitive behavior, learning and memory impairments, and motor coordination. However, there are no randomized placebo-controlled trials that support the clinical efficacy of flavonoids in ASD. We only found open-label studies and case reports/series, using only two flavonoids such as luteolin and quercetin. These preliminary clinical studies indicate that flavonoid administration may improve specific behavioral symptoms of ASD. Overall, this review is the first one to systematically report evidence for the putative beneficial effects of flavonoids on features of ASD. These promising preliminary results may provide the rationale for future randomized controlled trials aimed at confirming these outcomes.

 

It seems that the many flavonoids have numerous beneficial effects - this is why it is important to include them in your diet.

 

Sytrinol

Years ago, I wrote about Sytrinol, a dietary supplement that is made from citrus peel extract. It contains polymethoxylated flavones (PMFs), which are a type of flavonoid. It mainly contains nobiletin and tangeritin, flavones that are found in citrus fruits, such as lemons, oranges, and grapefruits. They have been shown to have a number of health benefits, including lowering cholesterol, reducing inflammation, and protecting cells from damage.

The idea was of interest because these flavones are known to activate PPAR-gamma, which seemed potentially beneficial in autism.  Readers did confirm Sytrinol provided a cognitive benefit, but it only lasts a few days and is then lost.

 

Sources of Apigenin

Apigenin is sold as a supplement.

Chamomile is one of the oldest, most widely used and well documented medicinal plants in the world and has been recommended for a variety of healing applications for centuries. Apigenin is thought to be one of the most potent substances found within it.

Bacopa monnieri is another rich source of flavonoids being a good source of luteolin and apigenin. An extract of Bacopa monnieri, a nootropic herb, has been used to evaluate its neuroprotective effect in a valproic acid (VPA) model of ASD. The results showed that B. monnieri extract may attenuate VPA-induced damage by restoring antioxidant enzymes and reducing inflammatory cytokines in the hippocampus and prefrontal cortex.

 

The biological effects of Apigenin

 What does the Google AI (artificial intelligence) program Bard have to say:-

 

Apigenin is a flavonoid that is found in a variety of plants, including chamomile, parsley, celery, and citrus fruits. It has several potential health benefits, including:

Antioxidant. Apigenin is an antioxidant, which means it can help protect cells from damage caused by free radicals. Free radicals are unstable molecules that can damage DNA, proteins, and other cellular structures.

Anti-inflammatory. Apigenin has anti-inflammatory properties, which can help reduce inflammation in the body. Inflammation is a contributing factor to many diseases, including heart disease, cancer, and arthritis.

Cancer prevention. Apigenin has been shown to have cancer-fighting properties in both animal and human studies. It may help prevent cancer by blocking the growth and spread of cancer cells.

Brain health. Apigenin may be beneficial for brain health. It has been shown to improve cognitive function in animal studies, and it may also help protect against Alzheimer's disease and other neurodegenerative diseases.

Heart health. Apigenin may help improve heart health. It has been shown to lower blood pressure and cholesterol levels, and it may also help protect against heart arrhythmias.

Hormone modulation. Apigenin may modulate the production of hormones, such as estrogen and testosterone. This could have benefits for women's health, such as reducing the risk of breast cancer and improving menopausal symptoms.

Immune health. Apigenin may boost the immune system. It has been shown to increase the production of white blood cells, which help fight infection.

Other benefits. Apigenin may also have other health benefits, such as relieving anxiety, promoting sleep, and strengthening bones.

When you push Bard a little bit you get more:

Apigenin and ion channels, Bard?

Apigenin is a flavonoid that has been shown to interact with a variety of ion channels in the body. These include:

Voltage-gated calcium channels. Apigenin has been shown to inhibit the activity of voltage-gated calcium channels, which are involved in the regulation of many cellular processes, including muscle contraction, cell growth, and cell death.

Transient receptor potential vanilloid 4 (TRPV4) channels. TRPV4 channels are activated by heat and inflammation, and they play a role in pain perception, thermoregulation, and inflammation. Apigenin has been shown to activate TRPV4 channels, which could have potential implications for the treatment of pain and inflammation.

Nicotinic acetylcholine receptors (nAChRs). nAChRs are ligand-gated ion channels that are activated by acetylcholine. They are involved in a variety of functions, including learning, memory, and muscle contraction. Apigenin has been shown to potentiate the activity of nAChRs, which could have potential implications for the treatment of Alzheimer's disease and other neurodegenerative diseases.

Potassium channels: Potassium channels are responsible for the efflux of potassium ions from cells. Apigenin has been shown to activate some types of potassium channels, which can have cardioprotective effects.

Gamma-aminobutyric acid (GABA)A receptors. GABAA receptors are ligand-gated ion channels that are activated by GABA. They are involved in the regulation of anxiety, sleep, and epilepsy. Apigenin has been shown to modulate the activity of GABAA receptors, which could have potential implications for the treatment of anxiety and epilepsy.

 

Which potassium channels, Bard? 

Apigenin has been shown to activate some types of potassium channels, including:

Small conductance calcium-activated potassium channels (SK channels): SK channels are activated by calcium ions and play a role in regulating cell excitability. Apigenin has been shown to activate SK channels in a number of cell types, including neurons, smooth muscle cells, and cardiac cells.

Large conductance calcium-activated potassium channels (BK channels): BK channels are also activated by calcium ions and play a role in regulating cell excitability and blood pressure. Apigenin has been shown to activate BK channels in some cell types, but the effects are less well-studied than the effects on SK channels.

Transient receptor potential vanilloid 4 (TRPV4) channels: TRPV4 channels are activated by a variety of stimuli, including heat, inflammation, and mechanical stress. Apigenin has been shown to activate TRPV4 channels in some cell types, but the effects are less well-studied than the effects on SK and BK channels.

 

The effect of mefenamic acid on potassium channels, Bard? 

Mefenamic acid has been shown to have effects on a variety of ion channels, including potassium channels.

In vitro studies have shown that mefenamic acid can activate certain types of potassium channels, such as small conductance calcium-activated potassium channels (SK channels) and large conductance calcium-activated potassium channels (BK channels). This activation of potassium channels can lead to a decrease in the excitability of cells, which can be beneficial in conditions where excessive cell excitability is a problem, such as epilepsy and arrhythmias.

 However, mefenamic acid can also inhibit certain types of potassium channels, such as ATP-sensitive potassium channels (KATP channels). This inhibition of KATP channels can lead to an increase in the excitability of cells, which can be harmful in conditions where excessive cell excitability is a problem, such as heart arrhythmias.

The effects of mefenamic acid on potassium channels are complex and depend on the type of channel, the concentration of mefenamic acid, and the cell type. More research is needed to fully understand the mechanisms by which mefenamic acid interacts with potassium channels and the implications for its potential therapeutic applications.

 

Apigenin in Down syndrome

 

Plant Compound Apigenin Reduces Cognitive Deficits in Mouse Model of Down Syndrome

Mice treated with apigenin had better memory and developmental milestone scores.

The plant compound apigenin improved the cognitive and memory deficits usually seen in a mouse model of Down syndrome, according to a study by researchers at the National Institutes of Health and other institutions.

Apigenin is found in chamomile flowers, parsley, celery, peppermint, and citrus fruits. The researchers fed the compound to pregnant mice carrying fetuses with Down syndrome characteristics and then to the animals after they were born and as they matured.

The findings raise the possibility that a treatment to lessen the cognitive deficits seen in Down syndrome could one day be offered to pregnant women whose fetuses have been diagnosed with Down syndrome through prenatal testing. The study appears in the American Journal of Human Genetics.

Down syndrome is a set of symptoms resulting from an extra copy or piece of chromosome 21. The intellectual and developmental disabilities accompanying the condition are believed to result from decreased brain growth caused by increased inflammation in the fetal brain.

Apigenin is not known to have any toxic effects, and previous studies have indicated that it is an antioxidant that reduces inflammation. Unlike many compounds, it is absorbed through the placenta and the blood brain barrier, the cellular layer that prevents potentially harmful substances from entering the brain.

Compared to mice with Down symptoms whose mothers were not fed apigenin, those exposed to the compound showed improvements in tests of developmental milestones and had improvements in spatial and olfactory memory. Tests of gene activity and protein levels showed the apigenin-treated mice had less inflammation and increased blood vessel and nervous system growth.

 

Apigenin as a Candidate Prenatal Treatment for Trisomy 21: Effects in Human Amniocytes and the Ts1Cje Mouse Model

Human fetuses with trisomy 21 (T21) have atypical brain development that is apparent sonographically in the second trimester. We hypothesize that by analyzing and integrating dysregulated gene expression and pathways common to humans with Down syndrome (DS) and mouse models we can discover novel targets for prenatal therapy. Here, we tested the safety and efficacy of apigenin, identified with this approach, in both human amniocytes from fetuses with T21 and in the Ts1Cje mouse model. In vitro, T21 cells cultured with apigenin had significantly reduced oxidative stress and improved antioxidant defense response. In vivo, apigenin treatment mixed with chow was administered prenatally to the dams and fed to the pups over their lifetimes. There was no significant increase in birth defects or pup deaths resulting from prenatal apigenin treatment. Apigenin significantly improved several developmental milestones and spatial olfactory memory in Ts1Cje neonates. In addition, we noted sex-specific effects on exploratory behavior and long-term hippocampal memory in adult mice, and males showed significantly more improvement than females. We demonstrated that the therapeutic effects of apigenin are pleiotropic, resulting in decreased oxidative stress, activation of pro-proliferative and pro-neurogenic genes (KI67, Nestin, Sox2, and PAX6), reduction of the pro-inflammatory cytokines INFG, IL1A, and IL12P70 through the inhibition of NFκB signaling, increase of the anti-inflammatory cytokines IL10 and IL12P40, and increased expression of the angiogenic and neurotrophic factors VEGFA and IL7. These studies provide proof of principle that apigenin has multiple therapeutic targets in preclinical models of DS.

 

Conclusion 

I am still delighted to have found a treatment for my son’s sound sensitivity, which got much more extreme almost overnight a couple of years ago.

I had already established long ago that he got short term sound sensitivity relief from taking a potassium supplement.  Some readers found a potassium supplement provided long term relief.

I thought that Ponstan might provide a good longer term solution and indeed it worked from the first pill.  This low dose therapy also works for other people with sound sensitivity, even one adult who has no autism.  The effective adult dose is 250 mg once a day.

Unlike other fenamate class drugs, like Diclofenac, Ponstan seems to be free from GI side effects at this low dose in most people.

Apigenin is an interesting alternative for those who do not tolerate Ponstan well, or who cannot access it.

A common link between what seems to improve sound sensitivity:

•                    Oral potassium

•                    Ponstan (Mefenamic acid)

•                    Apigenin

is potassium ion channels. 

If you ask Google’s AI program Bard, he will tell you:

“It is possible that all 3 substances could affect the same potassium ion channel in some cell types, but this has not been definitively shown. More research is needed to fully understand the effects of these substances on potassium ion channels.”

Technically Bard is genderless, but he is a reflection of the programmers behind the software. In our house he is called Bart anyway.

Bart does make mistakes, contradicts himself in the same answer and he gives you different answers if you ask the same question more than once. He is also prone to mixing things up, just like humans do.

Hypokalemic Autistic Sensory Overload

Hypokalemic Autistic Sensory Overload (HypoASO) is a condition causing distress to autistic people.  Moderately loud sounds, like those around an indoor swimming pool, or shopping mall, can cause an autistic person great irritation, leading to covering their ears, a tantrum, or even self-injurious behaviour (SIB).  The same sensory overload can be caused by light, smell or touch.  

HypoASO is a condition that can be measured and treated.

HypoASO is related to two other conditions Hypokalemic Periodic Paralysis and Hypokalemic Sensory Overstimulation.

HypoASO is an ion-channel disorder triggered by intra/extra cellular concentrations of sodium and potassium.  Calcium may also play a role.  In simple terms, sodium is bad and potassium is good.

Therapy for HypoASO

The therapy for HypoASO is a diet rich in potassium but low in sodium; magnesium will also be beneficial, since it helps maintain the level of potassium.  People with HypoASO need to maintain a high level of potassium in their blood (> 5.0 mmol/L) in order to avoid triggering this ion channel disorder;  this is at the high upper level of the reference range for potassium.   Oral supplements of potassium with magnesium will also prove useful, but need to be spread out throughout the day, for best effect.  Time release tablets should be the most effective.  Very high levels of potassium are dangerous, so care is required.

Testing for HypoASO

Diet should not be changed on a whim.  A simple test can be carried out to check whether the individual is indeed affected by the disorder. 

1.       Find a sound which the person finds disturbing, like a baby crying.

2.       Download a recording of this sound.

3.       Set up a chair in a fixed location in a room with a strong sound system / Hi Fi

4.       Sit the subject in the chair and play the annoying sound at ever greater volume and see at what point the subject reacts strongly (e.g. covers ears)

5.       Repeat the experiment over  a few days to establish a steady base-line volume, at which the subject reacts, (for example volume setting 3, when the amplifier to goes 0-10)

6.       Give the subject an oral potassium supplement (say 250 mg) and wait 20 minutes

7.       Play the annoying sound and measure the volume at which ears are covered.

8.       If the volume is markedly higher than the base-line, you established earlier, then you have established HypoASO

9.       If the subject has an NT sibling, try it on them.  They will most likely show no difference with the potassium and do not have HypoASO



 

Diamox & Bumetanide, Ion Channels Nav1.4 and Cav1.1, HypoPP, Autism and Seizures

So you’re going to spend some time at high altitude, climbing mountains or trekking, don’t forgetto pack your Diamox before you leave home, it can save your life.  She is right.

Today’s post links together subjects that have been covered previously.

It does suggest that there are multiple therapies that may be effective in the large sub-group of autism that is characterized by the neurotransmitter GABA being excitatory (E) rather than inhibitory (I).  The science was covered in the earlier very complicated post:-

GABA A Receptors in Autism – How and Why to Modulate Them

The growing list of potential therapies is:-

·        Bumetanide (awaiting funding for Stage 3 clinical trials in humans)

·        Micro-dose Clonazepam (trials in mouse models of autism)

·        Diamox (off-label use in autism)

·        Potassium Bromide  - to be covered in a later post (in use for 150 years)

Not surprisingly, all of these drugs also have an effect on certain types of seizure.

The optimal therapy in people with this E/I imbalance will likely be a combination of some of the above.

Periodic paralysis

Periodic paralysis (Hypokalemic periodic paralysis or HypoPP) is a rare condition that causes temporary paralysis that can be reversed by taking potassium.  A similar condition is hypokalemic sensory overload, when someone becomes overwhelmed by lights or sounds, but after taking potassium all goes back to normal. Autistic sensory overload, experienced by most people with autism, can also be reduced by potassium.

Though rare, we know that HypoPP is caused by dysfunction in the ion channels Na_v1.4 and/or Ca_v1.1.

For decades one of the treatments for HypoPP has been a diuretic called Diamox/Acetazolamide.

Other treatments include raising potassium levels using supplements or potassium sparing diuretics.

Bumetanide is a diuretic, but rather than raising potassium levels, it does the opposite.  So I always thought it was odd that bumetanide would have a positive effect on HypoPP.  But the research showed a benefit.

Autism and Channelopathies

We know that autism and epilepsy are associated with various ion channel and transporter dysfunctions (channelopathies).  In a recent post I was talking about Cav1.1 to Cav1.4.

Today we are talking about Cav1.1 and Nav1.4.

We know that Nav1.1 is associated with epilepsy and some autism (Dravet syndrome).

Nav1.4 is expressed at high levels in adult skeletal muscle, at low levels in neonatal skeletal muscle, and not at all in brain

Nav1.1 expression increases during the third postnatal week and peaks at the end of the first postnatal month, after which levels decrease by about 50% in the adult.

We saw with calcium channels that a dysfunction in one of Cav1.1 to Cav1.4 can cause a dysfunction in another dysfunction in another one of Cav1.1 to Cav1.4.

We also so that in autism the change in expression of NKCC1 and KCC2 as the brain matures failed to occur and so in effect they remain immature and therefore malfunction.

So it is plausible that sodium channels may also malfunction in a similar way. 

  

Acetazolamide efficacy in hypokalemic periodic paralysis and the predictive role of genotype

Hypokalemic periodic paralysis (hypoPP) is an autosomal dominant neuromuscular disorder characterized by episodes of flaccid skeletal muscle paralysis accompanied by reduced serum potassium levels. It is caused by mutations in one of two sarcolemmal ion channel genes, CACNA1S and SCN4A1-3 that lead to dysfunction of the dihydropyridine receptor or the alpha sub-unit of the skeletal muscle voltage gated sodium channel Nav1.4. Seventy to eighty percent of cases are caused by mutations of CACNA1S and ten percent by mutations of SCN4A4. 

There are no consensus guidelines for the treatment of hypoPP. Current pharmacological agents commonly used include potassium supplements, potassium sparing diuretics and carbonic anhydrase inhibitors (acetazolamide and dichlorphenamide). Dichlorphenamide is the only therapy for hypoPP to have undergone a randomized double blind placebo controlled cross over trial. This trial showed a significant efficacy of dichlorphenamide in reducing attack frequency but the inclusion criteria were based on clinical diagnosis of hypoPP and not genetic confirmation.

  

Ca_v1.1

Ca_v1.1 also known as the calcium channel, voltage-dependent, L type, alpha 1S subunit, (CACNA1S), is a protein which in humans is encoded by the CACNA1S gene

Na_v1.4

Sodium channel protein type 4 subunit alpha is a protein that in humans is encoded by the SCN4A gene.

The Na_v1.4 voltage-gated sodium channel is encoded by the SCN4A gene. Mutations in the gene are associated with hypokalemic periodic paralysis, hyperkalemic periodic paralysis, paramyotonia congenita, and potassium-aggravated myotonia.

Ranolazine

Ranolazine is an antianginal and anti-ischemic drug that is used in patients with chronic angina. Ranzoline blocks Na+ currents of Nav1.4. Both muscle and neuronal Na+ channels are as sensitive to ranolazine block as their cardiac counterparts. At its therapeutic plasma concentrations, ranolazine interacts predominantly with the open but not resting or inactivated Na+ channels. Ranolazine block of open Na+ channels is via the conserved local anesthetic receptor albeit with a relatively slow on-rate.

Muscle channelopathies:does the predicted channel gating pore offer new treatment insights for hypokalaemic periodic paralysis?

Beneficial effects of bumetanide in a CaV1.1-R528H mouse model of hypokalaemic periodic paralysis

Transient attacks of weakness in hypokalaemic periodic paralysis are caused by reduced fibre excitability from paradoxical depolarization of the resting potential in low potassium. Mutations of calcium channel and sodium channel genes have been identified as the underlying molecular defects that cause instability of the resting potential. Despite these scientific advances, therapeutic options remain limited. In a mouse model of hypokalaemic periodic paralysis from a sodium channel mutation (NaV1.4-R669H), we recently showed that inhibition of chloride influx with bumetanide reduced the susceptibility to attacks of weakness, in vitro. The R528H mutation in the calcium channel gene (CACNA1S encoding CaV1.1) is the most common cause of hypokalaemic periodic paralysis. We developed a CaV1.1-R528H knock-in mouse model of hypokalaemic periodic paralysis and show herein that bumetanide protects against both muscle weakness from low K⁺ challenge in vitro and loss of muscle excitability in vivo from a glucose plus insulin infusion. This work demonstrates the critical role of the chloride gradient in modulating the susceptibility to ictal weakness and establishes bumetanide as a potential therapy for hypokalaemic periodic paralysis arising from either NaV1.4 or CaV1.1 mutations.

Mode of action

The research does state that nobody knows why Diamox is effective in many cases of hypoPP.

My reading of the research has already taken me in a different direction.  While researching the GABA_A receptor that is dysfunctional in some autism, it occurred to me that in addition to targeting the NKCC1 receptor with bumetanide, another way of lowering chloride levels within the cells might well exist.

I suggested in an earlier post that Diamox could be used to target the AE3 exchanger.

What Diamox (acetazolamide) does is lower the pH of the blood in the following way.

Acetazolamide is a carbonic anhydrase inhibitor, hence causing the accumulation of carbonic acid Carbonic anhydrase is an enzyme found in red blood cells that catalyses the following reaction:

hence lowering blood pH, by means of the following reaction that carbonic acid undergoes

In doing so there will be an effect on both AE3 and NDAE, below.  This will change the intracellular concentration of Cl-, and hence give a similar result to bumetanide.

This would also explain the phenomenon cited below that pH affects the excitability of the brain.

Over excitability of the brain is the cause of some of the effects seen as autism and clearly Over excitability of the brain will be the cause of some people’s seizures/epilepsy.

Not surprisingly, then one of the uses of Diamox is to avoid seizures.

Acetazolamide in the treatment of seizures.

  

Anion exchanger 3 (AE3) in autism

Anion exchange protein 3 is a membrane transport protein that in humans is encoded by the SLC4A3 gene. It exchanges chloride for bicarbonate ions.  It increases chloride concentration within the cell.  AE3 is an anion exchanger that is primarily expressed in the brain and heart

Its activity is sensitive to pH. AE3 mutations have been linked to seizures

Characterization of an Epilepsy-associated variant of the AE3 Cl-/HCO3-exchanger

Bicarbonate (HCO₃^-) transport mechanisms are the principal regulators of pH in animal cells. Such transport also plays a vital role in acid-base movements in the stomach, pancreas, intestine, kidney, reproductive organs and the central nervous system.

Two types of chloride transporters are required for GABA_A receptor-mediated inhibition in C. elegans

Abstract

Chloride influx through GABA-gated Cl⁻ channels, the principal mechanism for inhibiting neural activity in the brain, requires a Cl⁻ gradient established in part by K⁺–Cl⁻ cotransporters (KCCs). We screened for Caenorhabditis elegans mutants defective for inhibitory neurotransmission and identified mutations in ABTS-1, a Na⁺-driven Cl⁻–HCO₃⁻ exchanger that extrudes chloride from cells, like KCC-2, but also alkalinizes them. While animals lacking ABTS-1 or the K⁺–Cl⁻ cotransporter KCC-2 display only mild behavioural defects, animals lacking both Cl⁻ extruders are paralyzed. This is apparently due to severe disruption of the cellular Cl⁻ gradient such that Cl⁻ flow through GABA-gated channels is reversed and excites rather than inhibits cells. Neuronal expression of both transporters is upregulated during synapse development, and ABTS-1 expression further increases in KCC-2 mutants, suggesting regulation of these transporters is coordinated to control the cellular Cl⁻ gradient. Our results show that Na⁺-driven Cl⁻–HCO₃⁻ exchangers function with KCCs in generating the cellular chloride gradient and suggest a mechanism for the close tie between pH and excitability in the brain.

NKCC1 and AE3 Appear to Accumulate Chloride in Embryonic Motoneurons

Abstract

During early development, γ-aminobutyric acid (GABA) depolarizes and excites neurons, contrary to its typical function in the mature nervous system. As a result, developing networks are hyperexcitable and experience a spontaneous network activity that is important for several aspects of development. GABA is depolarizing because chloride is accumulated beyond its passive distribution in these developing cells. Identifying all of the transporters that accumulate chloride in immature neurons has been elusive and it is unknown whether chloride levels are different at synaptic and extrasynaptic locations. We have therefore assessed intracellular chloride levels specifically at synaptic locations in embryonic motoneurons by measuring the GABAergic reversal potential (E_GABA) for GABA_A miniature postsynaptic currents. When whole cell patch solutions contained 17–52 mM chloride, we found that synaptic E_GABA was around −30 mV. Because of the low HCO₃⁻ permeability of the GABA_A receptor, this value of E_GABA corresponds to approximately 50 mM intracellular chloride. It is likely that synaptic chloride is maintained at levels higher than the patch solution by chloride accumulators. We show that the Na⁺-K⁺-2Cl⁻ cotransporter, NKCC1, is clearly involved in the accumulation of chloride in motoneurons because blocking this transporter hyperpolarized E_GABA and reduced nerve potentials evoked by local application of a GABA_A agonist. However, chloride accumulation following NKCC1 block was still clearly present. We find physiological evidence of chloride accumulation that is dependent on HCO₃⁻ and sensitive to an anion exchanger blocker. These results suggest that the anion exchanger, AE3, is also likely to contribute to chloride accumulation in embryonic motoneurons.

 

Conclusion

So the science does confirm that “chloride accumulation following NKCC1 block was still clearly present”.  This means that bumetanide is likely only a partial solution.

We also see that “anion exchanger, AE3, is also likely to contribute to chloride accumulation in embryonic motoneurons” and “that chloride accumulation that is dependent on HCO₃⁻”.

This is a subject of some research, but it is still early days.

Bicarbonate homeostasis in excitable tissues: role of AE3 Cl−/HCO3−exchanger and carbonic anhydrase XIV interaction

  

I suggest that Diamox, via its effect on HCO₃⁻, may affect anion exchanger AE3 and further reduce chloride accumulation within cells.  This may have a further cumulative effect on GABA.

As we saw earlier, bumetanide does indeed shift GABA from excitatory to inhibitory in people who neurons remain in an immature state (like those of a typical two week old baby).  To my surprise, the use of micro-dose Clonazepam, as proposed by Professor Catterall, but in addition to Bumetanide, has a further effect on GABA’s excitatory/inhibitory imbalance.

Taken together this would highlight the possible further benefit of Diamox.

Normal blood pH is tightly regulated between 7.35 and 7.45.  I do wonder if perhaps in some people with autism, the pH of their blood is slightly elevated (alkaline), this would contribute to excitability of the brain.

Since Diamox increases the oxygen carrying capacity of the blood, I further wonder if this additional oxygen may also be beneficial in some cases.  Since some people are adamant that hypobaric oxygen therapy has beneficial (although not sustained) effects in autism, surely a better treatment would be Diamox?

Since the body is controlled via so-called feedback loops, perhaps in a small subset of people with autism who respond to extra O₂, they actually have blood pH that is higher than 7.45.  In which case measuring blood pH would be a biomarker of who would respond to hypobaric oxygen therapy.  Not surprisingly then, trials of hypobaric oxygen therapy in autism fail, because most of the trial subjects do not have elevated blood pH.

  

So there are many reasons that Diamox should be trialed in autism.  I did find one (DAN) doctor currently using it, but they do not really explain why.

Biomedical Treatment of the Young Adult with ASD