Biotin & Triglycerides - why perhaps Fish Oil and Niacin may actually help a little in Autism & Schizophrenia

Far back in this blog, I wrote a post about fish oil.  Omega 3 oils are definitely good for your general health, but do they help with autism?  They are also claimed to help with ADHD and improve your NT child’s cognitive performance.

On critical review of the evidence, it seemed that the benefit was far from conclusive.  There was one very positive study, that neither the authors nor anyone else could repeat.

The following review of the literature by the University of Maryland show that, as with autism, studies on fish oil in depression, ADHD, bipolar and schizophrenia show conflicting results.

Omega-3 fatty acids

Some of the “cognitive enhancing” fish oil products are extremely expensive and I showed that regular fish consumption was far cheaper and likely to be as effective.

There is an issue of just how big an effect you are looking for.  We can all imagine tiny effects, but you really want an effect that everyone else notices.

Monty, aged 11 with ASD, eats lots of fish, mainly because he loves it.  He is not at all put off by those little bones.

The effect of fish oil on Monty was not noticeable.

Biotin

A recent post contained a study from Greece, where they found a remarkably high proportion of kids with ASD with a biotin deficiency.  This had not shown up on the standard test, because the standard test is strangely not for biotin at all; it tests for biotinidase, a related enzyme.

Identifying a biotin deficiency is not easy, blood tests are not helpful and you have to look at certain compounds found in urine.  As a result your local laboratory may not offer a useful test for biotin.

Since supplementation with pharmacological doses of biotin is known to be harmless, the practical way forward is to try it.

In the midst of looking at the relative effect of different primary antioxidants, I was substituting one thiol antioxidant (ALA) for another (NAC) to see if there was any obvious difference.  I could give lots of reasons, with scientific papers to back them up, as to why 0.6g of ALA plus 1.8g of NAC might be “better” than 2.4g of NAC, but it is not.  If anything, it might be worse.

Then I tried Carnosine in combination with NAC and again I could see absolutely no effect.

Then I decided to go back to my original NAC regime and add the biotin that had been on the shelf since Christmas. Very surprisingly, the effect that I thought might show up with ALA, showed up with biotin.  

It was not a huge effect, but a small step forward, that Monty’s assistant at school also noticed.  He was more calm and altogether more "normal". 

Does this mean Monty has a biotin deficiency?  It is of course possible.  In the Greek study 4% of the kids were thought to have such a deficiency, far more than expected, and most did respond, in varying degrees, to biotin supplements.  Unfortunately they only gave the biotin to the 4%; I would like to know what would have happened to the remaining 96%.

Biotin lowers Triglycerides and Elevated Triglycerides are associated with Mood Disorders   

Biotin is a B vitamin, but very little is actually known about it.

Then I found the link I was looking for.

Biotin does not lower cholesterol, but it does reduce (in a big way) your Triglycerides.

Several studies have shown that elevated Triglycerides are associated with all kinds of disorders: bipolar, depression and schizophrenia.  These studies suggested a causal link between the mood disorder and the elevated triglyerides.

Other Effects on Mood

          Besides depression, high levels of triglycerides are also correlated with other affective disorders including bipolar disorder (manic depression), schizoaffective disorders, aggression and hostility. In fact, the poor nutritional status of many depressed persons, who often have diets high in fats, can be improved to lessen the depression, according to Charles Glueck, MD, medical director of the Cholesterol Center of Jewish Hospital in Cincinnati.

"We have shown that in patients with high triglycerides who were in a depressive state, the more you lower the triglycerides, the more you alleviate the depression," Glueck wrote in a 1993 article in Biological Psychiatry.

According to the U.S. Centers for Disease Control and Prevention (CDC), most Americans aren't aware of the role triglycerides play in physical and mental health. A five-year study of more than 5,000 Americans found that 33 percent of them had borderline high triglyceride levels.

Improvement in symptoms of depression and in an index of life stressors accompany treatment of severe hypertriglyceridemia.

In 14 men and nine women referred because of severe primary hypertriglyceridemia, our specific aim in a 54-week single-blind treatment (Rx) period was to determine whether triglyceride (TG) lowering with a Type V diet and Lopid would lead to improvement in symptoms of depression, improvement in an index of life stressors, change in locus of control index, and improved cognition, as serially tested by Beck (BDI), Hassles (HAS) and HAS intensity indices, Locus of Control index, and the Folstein Mini-Mental status exam. On Rx, median TG fell 47%, total cholesterol (TC) fell 15%, and HDLC rose 19% (all p < or = 0.001). BDI fell at all nine Rx visits (p < or = 0.001), a major reduction in a test of depressive symptoms. The HAS score also fell at all nine visits (p < or = 0.05 - < or = 0.001). Comparing pre-Rx baseline BDI vs BDI at 30 and 54 weeks on Rx, there was a major shift towards absence or amelioration of depressive symptoms (chi 2= 5.9, p = 0.016). On Rx, the greater the percent reduction in TG, the greater the percent fall in BDI (r = 0.47, p < or = 0.05); the greater the percent reduction in TC, the greater the percent fall in HAS (r = 0.41, p < or = 0.05). Improvement in the BDI and HAS accompanied treatment of severe hypertriglyceridemia, possibly by virtue of improved cerebral perfusion and oxygenation. There may be a reversible causal relationship between high TG and symptoms of depression.

Mood symptoms and serum lipids in acute phase of bipolar disorder inTaiwan.

 

Abstract

Serum lipids have been found to play important roles in the pathophysiology of mood disorders. The aim of the present study was therefore to investigate the relationship between symptom dimensions and serum cholesterol and triglyceride levels, and to explore correlates of lipid levels during acute mood episodes of bipolar I disorder in Taiwan. Measurements were taken of the serum cholesterol and triglyceride levels in patients with bipolar I disorder hospitalized for acute mood episodes (68 manic, eight depressive, and six mixed). The relationships between serum lipids levels and various clinical variables were examined. The mean serum levels of cholesterol (4.54 mmol/L) and triglycerides (1.16 mmol/L) of sampled patients were comparable to those of the general population in the same age segment. Severe depressive symptoms and comorbid atopic diseases were associated with higher serum cholesterol levels. A negative association was noted between serum triglyceride levels and overall psychiatric symptoms. Compared with previous studies on Western populations, racial differences may exist in lipids profiles of bipolar disorder patients during acute mood episodes. Increased serum cholesterol levels may have greater relevance to immunomodulatory system and depressive symptoms, in comparison with manic symptoms.

Biotin supplementation reduces plasma triacylglycerol and VLDL in type 2 diabetic patients and in non-diabetic subjects with hypertriglyceridemia.

Abstract

Biotin is a water-soluble vitamin that acts as a prosthetic group of carboxylases. Besides its role as carboxylase prosthetic group, biotin regulates gene expression and has a wide repertoire of effects on systemic processes. The vitamin regulates genes that are critical in the regulation of intermediary metabolism. Several studies have reported a relationship between biotin and blood lipids. In the present work we investigated the effect of biotin administration on the concentration of plasma lipids, as well as glucose and insulin in type 2 diabetic and nondiabetic subjects. Eighteen diabetic and 15 nondiabetic subjects aged 30-65 were randomized into two groups and received either 61.4 micromol/day of biotin or placebo for 28 days. Plasma samples obtained at baseline and after treatment were analyzed for total triglyceride, cholesterol, very low density lipoprotein (VLDL), glucose and insulin. We found that the vitamin significantly reduced (P=0.005) plasma triacylglycerol and VLDL concentrations. Biotin produced the following changes (mean of absolute differences between 0 and 28 day treatment+/-S.E.M.): a) triacylglycerol -0.55+/-0.2 in the diabetic group and -0.92+/-0.36 in the nondiabetic group; b) VLDL: -0.11+/-0.04 in the diabetic group and -0.18+/-0.07 in the nondiabetic group. Biotin treatment had no significant effects on cholesterol, glucose and insulin in either the diabetic or nondiabetic subjects. We conclude that pharmacological doses of biotin decrease hypertriglyceridemia. The triglyceride-lowering effect of biotin suggests that biotin could be used in the treatment of hypertriglyceridemia.

The hypotriglyceridemic effect of biotin supplementation involves increased levels of cGMP and AMPK activation

Abstract

In addition to its role as a carboxylase cofactor, biotin modifies gene expression and has manifold effects on systemic processes. Several studies have shown that biotin supplementation reduces hypertriglyceridemia. We have previously reported that this effect is related to decreased expression of lipogenic genes. In the present work, we analyzed signaling pathways and posttranscriptional mechanisms involved in the hypotriglyceridemic effects of biotin. Male BALB/cAnN Hsd mice were fed a control or a biotin-supplemented diet (1.76 or 97.7 mg of free biotin/kg diet, respectively for 8 weeks after weaning. The abundance of mature sterol regulatory element-binding protein (SREBP-1c), fatty-acid synthase (FAS), total acetyl-CoA carboxylase-1 (ACC-1) and its phosphorylated form, and AMP-activated protein kinase (AMPK) were evaluated in the liver. We also determined the serum triglyceride concentrations and the hepatic levels of triglycerides and cyclic GMP (cGMP). Compared to the control group, biotin-supplemented mice had lower serum and hepatic triglyceride concentrations. Biotin supplementation increased the levels of cGMP and the phosphorylated forms of AMPK and ACC-1 and decreased the abundance of the mature form of SREBP-1c and FAS. These data provide evidence that the mechanisms by which biotin supplementation reduces lipogenesis involve increased cGMP content and AMPK activation. In turn, these changes lead to augmented ACC-1 phosphorylation and decreased expression of both the mature form of SREBP-1c and FAS. Our results demonstrate for the first time that AMPK is involved in the effects of biotin supplementation and offer new insights into the mechanisms of biotin-mediated hypotriglyceridemic effects.

Triglycerides are also elevated in autism:-

Alterations in lipid profile of autistic boys: a case control study.

Abstract

We hypothesize that autism is associated with alterations in the plasma lipid profile and that some lipid fractions in autistic boys may be significantly different than those of healthy boys. A matched case control study was conducted with 29 autistic boys (mean age, 10.1 +/- 1.3 years) recruited from a school for disabled children and 29 comparable healthy boys from a neighboring elementary school in South Korea. Fasting plasma total cholesterol (T-Chol), triglyceride (TG), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), the LDL/HDL ratio, and 1-day food intakes were measured. Multiple regression analyses were performed to assess the association between autism and various lipid fractions. The mean TG level (102.4 +/- 52.4 vs 70.6 +/- 36.3; P = .01) was significantly higher, whereas the mean HDL-C level (48.8 +/- 11.9 vs 60.5 +/- 10.9 mg/dL; P = .003) was significantly lower in cases as compared to controls. There was no significant difference in T-Chol and LDL-C levels between cases and controls. The LDL/HDL ratio was significantly higher in cases as compared to controls. Multiple regression analyses indicated that autism was significantly associated with plasma TG (beta = 31.7 +/- 11.9; P = .01), HDL (beta = -11.6 +/- 2.1; P = .0003), and the LDL/HDL ratio (beta = 0.40 +/- 0.18; P = .04). There was a significant interaction between autism and TG level in relation to plasma HDL level (P = .02). Fifty-three percent of variation in the plasma HDL was explained by autism, plasma TG, LDL/HDL ratio, and the interaction between autism and plasma TG level. These results indicate the presence of dyslipidemia in boys with autism and suggest a possibility that dyslipidemia might be a marker of association between lipid metabolism and autism.

Omega-3 Oil and Niacin in Schizophrenia

Like Autism, Schizophrenia is another observational diagnosis, with many different underlying genetic and environmental causes.  I keep referring to it as adult-onset autism.  It is also characterized by oxidative stress.

I found it interesting that two very widely used therapies for schizophrenia are omega-3 fish oil and high doses of niacin.  2 g a day of NAC is another common therapy in schizophrenia.

The clinical trials of omega-3 oil in schizophrenia, are just like the ones in autism, far from conclusive.  Yet people with schizophrenia continue to buy the expensive EPA fish oils, just like many parents of children with autism.

Another very popular treatment is Niacin.

Niacin does many things but these include increasing your HDL (good) cholesterol, reduce LDL (bad) cholesterol and, importantly, can reduce triglycerides by up to 50%.

Management of Hypertriglyceridemia

Niacin in Anxiety

Supplemental Niacinamide Mitigates Anxiety Symptoms: Three Case Reports

Niacin in autism

People do use high dose niacin and niacinamide in autism, but in general niacin levels are totally normal in people with autism, according to this study:-

Nutritional and metabolic status of children with autism vs. neurotypical children, and the association with autism severity

For the vitamins, the only significant difference was a 20% lower biotin (p < 0.001) in the children with autism. There were possibly significant (p < 0.05) lower levels of vitamin B5, vitamin E, and total carotenoids. Vitamin C was possibly slightly higher in the children with autism. Vitamin B6 (measured as the active form, P5P, in the RBC) had an unusually broad distribution in children with autism compared to controls (see Figure ​Figure1),1), with the levels in the children with autism having 3 times the standard deviation of the neurotypical children.

Niacin was very similar in the autism group (7.00 μg/l and the control group (7.07 μg/l)

Other interesting findings highlighted the usual metabolic differences:-

·        ATP, NADH, and NAHPH were significantly different between the autism and neurotypical groups

·        Sulfation, methylation, glutathione, and oxidative stress biomarkers which were significantly different between the autism and neurotypical groups

·        Amino Acids which were significantly different between the autism and neurotypical groups, rescaled to the average neurotypical value

Peter Triglyceride Hypothesis in Autism & Schizophrenia

Elevated triglycerides in autism/schizophrenia may contribute to behavioral/mood problems.  The lipid contribution to the dysfunction may be correlated to elevation of triglycerides.  In other words triglycerides aggravate the existing disorder.

Some CAM treatments currently used in autism/schizophrenia, including high dose niacin, high dose biotin and high dose omega 3 oils may be effective due to their ability to lower triglycerides.

Biotin may be the safest, cheapest and most effective option to reduce triglycerides and improve mood/behavior.

The underlying cause of lipid dysfunction in autism/schizophrenia is the ongoing oxidative stress.

Fish oil is claimed to be good for your heart, but it has been shown not to affect cholesterol levels.  In some studies it did lower triglycerides.  In some countries doctors prescribe omega-3 oil to patients with stubbornly high triglycerides.  Perhaps they should read the research and try biotin?

  

Other functions of biotin

Biotin does have other more complex functions and the triglycerides may, so to speak, be a red herring.

Regulation of gene expression by biotin (review).

Abstract

In mammals, biotin serves as coenzyme for four carboxylases, which play essential roles in the metabolism of glucose, amino acids, and fatty acids. Biotin deficiency causes decreased rates of cell proliferation, impaired immune function, and abnormal fetal development. Evidence is accumulating that biotin also plays an important role in regulating gene expression, mediating some of the effects of biotin in cell biology and fetal development. DNA microarray studies and other gene expression studies have suggested that biotin affects transcription of genes encoding cytokines and their receptors, oncogenes, genes involved in glucose metabolism, and genes that play a role in cellular biotin homeostasis. In addition, evidence has been provided that biotin affects expression of the asialoglycoprotein receptor and propionyl-CoA carboxylase at the post-transcriptional level. Various pathways have been identified by which biotin might affect gene expression: activation of soluble guanylate cyclase by biotinyl-AMP, nuclear translocation of NF-kappaB (in response to biotin deficiency), and remodeling of chromatin by biotinylation of histones. Some biotin metabolites that cannot serve as coenzymes for carboxylases can mimic biotin with regard to its effects on gene expression. This observation suggests that biotin metabolites that have been considered "metabolic waste" in previous studies might have biotin-like activities. These new insights into biotin-dependent gene expression are likely to lead to a better understanding of roles for biotin in cell biology and fetal development.

It does appear that biotin is more important than generally appreciated. 

Conclusion

In earlier posts I highlighted that elevated cholesterol is a bio-marker for inflammation.  In a large sub-group in autism, cholesterol is elevated.

In today’s post we looked at  a different type of lipid, triglycerides, they have a different role to cholesterol.  Not surprisingly the lipid profile is dysfunction, since it is closely linked to oxidative stress, which appears to be at the root of many problems in autism.

It is extremely easy and inexpensive to check your lipid profile (LDL, HDL and triglycerides); if elevated, there are safe established ways to bring things back to “normal”.

Parents seeing a small positive effect with their fish oil supplements might consider saving a lot of money and seeing if an extremely inexpensive biotin (5mg) supplement has an equal or greater effect.  The cost of biotin would be $2 a month.  The cost of fish oil with anything like the concentration used in the more effective trials (0.84g EPA and 0.7g DHA) will cost around $50 a month and may not lower triglycerides by as much as the cheap biotin.

By measuring the lipid profile before and after, you will be able to determine for yourself the relative merits.

Niacin also has been shown to improve mood/anxiety.  It is used by people with autism and schizophrenia.  Niacin is also extremely effective at reducing triglycerides.  High doses of Niacin can be accompanied by side effects and so use is discouraged.

Biotin levels do seem to be slightly low in autism.  Effective methods of accurately diagnosing deficiency are disputed.  Biotin is very effective at reducing triglycerides.

Elevated triglycerides have been associated with mood disorders and depression.

It seems plausible that the benefits from Omega-3 , niacin and biotin stem from their effectiveness in reducing triglycerides.

Biotin would seem to be a very cost effective and safe way to achieve this, without the side effects of niacin.  

Biotin also appears to have other key functions, including transcription of cytokine genes. Over expression of pro-inflammatory cytokines is a common feature of autism.

Broccoli soup at school – washed down with a little grapefruit juice

A growing number of readers have discovered the remarkable effects of a specific preparation of broccoli sprout powder.  It was my suggested method to match the Sulforaphane, made in the lab at Johns Hopkins, and recently trialed with great results in young adults with autism.

I did mention to therapists working with Monty, aged 11 with ASD, what a surprise there would be at the local special school if they served up some extra-potent broccoli soup for lunch one day.  There would be some very bemused teachers and parents.  It would also be the world's cheapest randomized trial on 100 people and the fastest. (you would just have to note down who actually ate the soup, but I think it would be obvious later)

Since another reader stumbled upon the anti-oxidant capability of grapefruit juice the other day, I would add some of that to the school lunch.  Preferably pink grapefruit, since they also would have a dose of lycopene, another potent antioxidant.

As fate would have it, a trial is underway with a jar of the aforementioned broccoli powder.  It is not at the local special school, but at a private center for speech & behavioral therapy.  

A reader of this blog has told someone else, who then tried it on their child and now someone else has bought a jar to try on the children at the center.

Of course, in a litigious country, nobody would dream of doing this; but in some countries, common sense still prevails.

I do hope the center keeps a note of who tried it and what the effects were, so we can have some statistics.  The good thing is that because it is so fast-acting, the therapist will observe the effects unfolding within the very same session.

Since the main effects are on mood and speech, a speech therapist is probably the best person to observe and quantify the effect.

In the kind of children who attend such centers, where autism is a disability rather than a difference, I think the response rate with be really high.  I would guess 70+%.  If they want to write up a report, I will be delighted to post it on this blog.

Anyway, I give them 10 out of 10 for initiative.

Targeted pharmacological treatment of autism spectrum disorders: fragile X and Rett syndrome

Today’s post is to refer the scientists among you to a very thorough paper looking at possible drug therapies for two specific variants of autism, Fragile X and Rett Syndrome.

Targeted pharmacological treatment of autism spectrum disorders: fragile X and Rett syndromes

  

These are single gene autisms and, as such, it is very much easier to study them than classic autism(s) or regressive autism(s).

We have already seen that much can be learnt from Fragile X and Retts.  What helps treat these disorders may give useful pointers to treat other types of autism and some therapies may be directly transferable, in some cases.

Note the use of baclofen, memantine, lovastatin, rapamycin, a PAK inhibitor, two potassium channel drugs, oxytocin, and even lithium.

Ganaxalone is a positive allosteric modulator of the GABA_A receptor, probably affects the neurosteroid site.  It does not have the drawbacks of benzodiazepines.  I wonder whether it exhibits interesting effects at tiny doses? 

Tuning GABAa receptors

Treatment of Autism with low dose Phenytoin

Acamprosate appears to be neuro-protective, but the mechanism of action is unknown and controversial.  It is a drug a drug used for treating alcohol and benzodiazepine dependence.  A surprising number of off-label autism drugs are used for to treat substance abuse.

The paper is well worth a read for those who are heavily into the subject.

Tuning GABAa receptors, plus Oxytocin

Today’s post will hopefully not get too complicated.

As has been mentioned in this blog, and also at leading institutions like MIT, it does seem possible to fine-tune certain receptors in the brain that have become dysfunctional in autism.  In the case of MIT they were “tuning” a receptor called mGluR5, which they suggested was either hypo or hyper, in other words too much or too little, depending on what the underlying disease variant was.

This was done with something called an allosteric modulator, either a positive one called PAM, or a negative one called NAM.

They found that a particular glumate receptor, called mGluR5, was dysfunction in many autism-like conditions.  But the nature of the dysfunction varied, so different people would require different treatments to return the receptor performance back to normal (top dead center).   So it really becomes like tuning your car engine. 

As I have progressed in my review of the literature it becomes clear that numerous receptors are “out of tune”; so a better analogy is tuning something like a piano.

  

Ketamine, Memantine, D-Cycloserin, Magnesium, Fenobam and yet more as Glutamatergic Modulators in Autism (and Fragile X)

"Tuning" the shape (but not number) of dendritic spines also appears not to be as fanciful as it sounds.

Back to GABA_A

Regular readers will know that one of the key dysfunctional receptors in autism is called GABA_A.

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

This subject is very complicated.  In effect what appears to have happened in autism is that the neurons have not matured as they should, and so GABA_A receptors continue to function in their “normal” immature state.  The concentration of chloride remains high since the NKCC1 transporter continues to exist, whereas KCC2/3 should have developed.  The result is that when the receptor is stimulated, instead of causing an inhibitory/calming effect it causes an excitatory effect.

This is fortunately treatable by inhibiting the flow of chloride into the cells, through NKCC1, using a drug called Bumetanide.

However this is not the end of the story.

At least 11 binding sites on GABA_A receptors

As you can learn from Wikipedia:-

The active site of the GABA_A receptor is the binding site for GABA and several drugs such as muscimol, gaboxadol, and bicuculline. The protein also contains a number of different allosteric binding sites which modulate the activity of the receptor indirectly. These allosteric sites are the targets of various other drugs, including the benzodiazepines, nonbenzodiazepines, barbiturates, ethanol, neuroactive steroids, inhaled anaesthetics, and picrotoxin, among others.

We are particularly interested in the allosteric binding sites.

The only one that is usually referred to, in any depth, is the site for benzodiazepines, but there are at least 11 different binding sites.

GABAa receptor pharmacology.

Abstract

gamma-Aminobutyric acid (GABA)a receptors for the inhibitory neurotransmitter GABA are likely to be found on most, if not all, neurons in the brain and spinal cord. They appear to be the most complicated of the superfamily of ligand-gated ion channels in terms of the large number of receptor subtypes and also the variety of ligands that interact with specific sites on the receptors. There appear to be at least 11 distinct sites on GABAA receptors for these ligands.

Development of Subtype-Selective GABAA Receptor Compounds for the Treatment of Anxiety, Sleep Disorders and Epilepsy

These sites include:-

·        GABA Binding Site

·        Benzodiazepine Binding Site

·        Neurosteroid Binding Site

·        Convulsant Binding Site

·        Barbiturate Binding Site

·        b Subunit Binding Site(s)

In an earlier post I highlighted the discovery by Professor Catterall, that tiny doses of a particular Benzodiazepine drug called Clonazepam had a strange effect on the GABA_A receptor.

Clonazepam is a known Positive Allosteric Modulator (PAM) of the GABA_A site.  In mature neurons it amplifies the calming effect when the GABA binding site is stimulated.  In mouse models of autism (we assume therefore immature neurons)   where GABA is still excitatory, the tiny dose seemed to switch it to inhibitory.

This suggests a new function, rather than a PAM, the effect was to invert the function entirely.

Now it appears that similar things may indeed also be possible at some of the other 9+ binding sites (I exclude GABA Binding Site itself)

As complicated as this subject may sound, it actually gets even more complicated since the GABA receptors are made up of sub-units.  It appears that mutations in these subunits may be a cause of some epilepsies and, I propose, some “oddities” in autism.

Recent studies have again shown that many genetic dysfunctions found in autism relate to GABA, this short article is not so recent, but gives a nice summary:-

GABA is the major inhibitory neurotransmitter in the brain. It essentially acts as a brake for brain activation. Several aspects of GABA regulation have been linked to ASD, from early brain development to adult brain function.

Variations in GABA receptor subunits have been strongly associated with ASD. GABA receptors come in two major forms: fast, “ionotropic” GABAA receptors let negatively charged chloride ions flow into the neuron, and slow, “metabotropic” GABAB receptors produce chemical messages inside the neuron. GABAA receptors, the most common form in the brain, contain five subunits that shape their properties. Genome-wide association studies have linked the GABAA receptor subunit genes GABRA4 (α4 subunit), GABRB1 (β1 subunit), and GABRB3 (β3 subunit) to autism.[1][2] In addition, deletion of a chromosomal region that contains a cluster of a variety of GABA receptor genes (region 15q11-13) causes Angelman Syndrome.[3][4]

Genes controlling the development of GABA-releasing neurons have also been associated with ASD. Autism-linked variations in the ARX and DLX family of transcription factors interfere with proper expression of GABA.[5][6][7] Absence of such GABA-releasing neurons would negatively affect early brain development as well as adult brain stability.

Notably, variations in other ASD-linked genes affect GABA signaling. New evidence shows that the gene MECP2, the mutation of which causes Rett Syndrome, is critical for normal function of GABA-releasing neurons.[8] When MECP2 expression was blocked in GABAergic neurons of mice, GABA expression and release were reduced and the mice exhibited autistic behaviors.

ASD is a complex disorder that is likely to be caused by a combination of mutations in a variety of genes. GABA receptors are a promising therapeutic target because of their important role in monitoring brain excitation. Identification and exploration of autism-linked mutations in other GABA-related genes could shed light on the pathogenesis of autism.

Over to Switzerland

At the University of Bern a small research group is looking  at the world of  GABA_A receptors, here is what they say:-

“Many scientists and companies are put off by the complexity of the field of GABA_A receptors, but it is exactly this complexity that offers numerous possibilities of fine-tuned pharmacological interventions.” 

Prof.Dr. Erwin Sigel

Here is one of their recent papers, that shows both what is known and how very much remains unknown.

Structure, Function, and Modulation of GABAA Receptors

Ion Conductance

The GABA_A receptors are generally GABA-gated anion channels selective for Cl⁻ ions, with some permeability for bicarbonate anions (49). Exceptionally, in C. elegans, a cation-selective GABA-gated channel has been discovered (50). Excitatory neurotransmitters increase the cation conductance to depolarize the membrane, whereas inhibitory neurotransmitters increase the anion conductance to tendentially hyperpolarize the membrane. However, if the gradient for Cl⁻ ions decreases due to down-regulation of KCC2 chloride ion transporters, opening of GABA_A receptors may cause an outward flux of these anions, leading to depolarization of the membrane and thereby to excitation. This phenomenon has been implicated in neuropathic pain (51). During early development (52) and in neuronal subcompartments (53), GABA similarly confers excitation. 

Although it is relatively simple to address questions at the level of individual receptor subunit isoforms, we can only speculate how many GABA_A receptors are expressed in our brain and what their subunit composition is, not to mention subunit arrangement.

Conclusions

Many scientists and companies are put off by the complexity of the field of GABA_A receptors, but it is exactly this complexity that offers numerous possibilities of fine-tuned pharmacological interventions.

It may be anticipated that genetic alterations of subunits of the GABA_A receptor affect any of the above mentioned processes and thereby contribute to inherited human diseases. A start has been made with the analysis of point mutations that cause epilepsy

Mutations in GABAA receptor subunits associated with genetic epilepsies

Why is all this relevant ?

We have in recent posts discovered that at least two anti-convulsants (carbamazepine and phenytoin) appear to modulate GABAA receptors in unexpected ways when given in tiny doses.

We also found out that valproate also seems to possess such qualities.  The exact mode of action of valproate is not known and perhaps it also acts a modulator of one of the many binding sites on the GABAA receptors.

We do think that valproate is working somehow via GABA.

Modulation of the gamma-aminobutyric acid type A receptor by the antiepileptic drugs carbamazepine and phenytoin

It turns out that Carbamazepine has also been shown to potentiate GABA receptors made up of alpha1, beta2, and gamma2 subunits.

I have already established that the effect of tiny doses of Valproate is not the same as tiny doses of Clonazepam.

The next step would be to look at the effect of tiny doses of carbamazepine, phenytoin and potentially anything else that modulates those mysterious  GABA_Asites.  They are clearly all there for a reason.  It seems that their role goes beyond just the allosteric modulation (amplification/reduction) of GABA’s effect.  It is likely much more subtle and they affect emotional behaviour.

Given the difficulty/impossibility of research on human brains, in the end we may need to revert to the medical world’s often used “scientific” discovery methods known as trial and error, and stumbled upon.

For the moment that will be left to Professors Sigel and Catterall and their mice, and Dr Bird, in Australia, with his human subjects.

Oxytocin and Bumetanide share the same mode of action in autism

Whilst on the subject of GABA_A, I should come back to Oxytocin.

Oxytocin-Mediated GABA Inhibition During Delivery Attenuates Autism Pathogenesis in Rodent Offspring

The conclusion of this Ben-Ari paper from last year is that Oxytocin and Bumetanide share the same effect in autism; they lower the level of chloride within the neurons and help switch GABA back to inhibitory.

It seems that oxytocin from the mother may be the signal to the developing brain to lower Cl levels.  Oxytocin has many other functions in the body.

Small doses of oxytocin/Syntocinon, have been shown to be effective in some people with autism.  One reader from Portugal has written on this blog how effective it has been in his young son.

Oxytocin/Syntocinon is not available everywhere, but is being reintroduced to the US.

Retrophinto reintroduce Syntocinon™ Nasal Spray in the U.S. and Develop the Drug for Schizophrenia and Autism

I am wondering if in some people, who are not responders, bumetanide/oxytocin lowers the level of chloride, but not enough to show any benefit.  People using Bumetanide, which has a short half-life, comment that the effect fades through the day and that splitting the same daily dose 3 times a day is beneficial over 2 times a day.  This might suggest that combining Oxytocin with Bumetanide might give better results, by maintaining the downward pressure on chloride levels and keeping GABA more inhibitory and for longer.

In the longer term, an analog of Bumetanide is needed without the diuretic effect and with a delayed release, to maintain a constant effective level.  This is known to the researchers, but would require a big financial investment.

Larger doses of oxytocin are likely to produce effects elsewhere in the body.

If anyone tries the combination of Bumetanide + oxytocin, let me know.