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Thursday 23 November 2017

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. 


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. 


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

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. 

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. 


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 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:-  


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:-


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. 

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. 


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. 


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.









Friday 17 November 2017

Beetroot - Cold Hands, Leukoaraiosis, Psychosis and Anxiety in Schizophrenia





Karimnagar, India, where Schizophrenic Rats respond well to Beetroot Juice

If you are not old enough to be interested in dementia, skip through those parts of this post and read about schizophrenic mice and beetroot juice.
There have been earlier posts regarding using nitric oxide (NO) to improve circulation and derive a cognitive benefit.
Many sportsmen have followed up on the research studies that show exercise endurance is improved after taking beet root juice. Since it is not a banned substance they are free to benefit from it.
We know that beet root does not only reduces blood pressure but it actually can increases perfusion, or blood flow, to the brain. Reduced blood flow to the brain is a feature of some dementia. Studies have used MRI to show that circulation is increased. A follow up study has recently been published which shows that beet root juice combined with exercise produced MRI results that resemble those of much younger adults.
In a previous post we saw that cocoa flavanols improved memory in older people and in effect brought them back to where they used to be 20 years previously. With cocoa the mechanism is not fully understood by is believed to “activate the nitric oxide system” in the brain. Cocoa does not produce nitric oxide in the way beet root does. Foods like beetroot and spinach contain large amounts of nitrates and they cause a measurable increase in circulating nitrites in the blood. The nitrites can later on become nitric oxide.
There is a lot of research into cocoa flavanols, mainly in relation to its benefit for those heart disease and more recently dementia. It also has benefits for anyone with diabetes, because it increases insulin sensitivity, as some readers of this blog have confirmed.
Cocoa flavanols appear to indirectly increase eNOS which then leads to more Nitric Oxide (NO). In addition there are antioxidant effects. eNOS reacts with L-arginine to produce NO.
But there is another way to make Nitic Oxide (NO), via nitrite that is circulating in your blood.  To increase nitrite you just eat nitrates, green leafy vegetables and beetroot.
It appears that eNOS does affect nitrite levels, so perhaps more eNOS means more NO is produced and then nitrite stays as nitrite and so the level of nitrite increases. Everything is inter-related.




Interestingly, statin drugs increase circulating nitrite levels just like beetroot.
NO bioavailability is determined by the balance between NO biosynthesis and its degradation by reactions with hemoglobin and reactive oxygen species (ROS).



So in people with oxidative stress there will be less NO. 

Nitric oxide (NO) is a potent signaling molecule that influences an array of physiological responses. It was traditionally assumed that NO was derived exclusively via the nitric oxide synthase (NOS) family of enzymes. This complex reaction requires a five electron oxidation of L-arginine and is contingent on the presence of numerous essential substrates (including O2) and co-factors. Recently an additional, O2-independent, NO generating pathway has been identified, where nitrite (NO2 ) can undergo a simple one electron reduction to yield NO. NO2 is produced endogenously from the oxidation of NO and also from the reduction of dietary nitrate (NO3 ) by facultative bacteria residing on the tongue. Recent data show that dietary NO3 supplementation, which increases the circulating plasma [NO2 ], reduces the O2 cost of submaximal exercise in healthy humans. This finding is striking given that efficiency during moderate-intensity exercise has been considered to be immutable. Therefore, dietary NO3 supplementation may represent a practical and cost-effective method to improve exercise efficiency and exercise tolerance in humans. Given that a NO3 -rich diet may have numerous cardiovascular and other health benefits, dietary NO3 intake may have important implications for human lifelong health and performance.
   
Cold hands
People with poor circulation tend to have cold hands and feet. From the comments in this blog it appears that many people with autism have cold hands/feet.
Do the many Nitric Oxide producing therapies used by sportsmen “warm up” cold hands?
Well we do actually now have some data on this subject. 


At least in the case of beetroot the answer is no.


L-arginine, L-citrulline, eNOS and NO    
It does appear that more eNOS can be beneficial. More eNOS means more NO as long as there is enough L-arginine. If you want to make more L-arginine, the most effective way is to eat L-citrulline, which is abundant in water melon.
It looks like some people lack arginine while others lack eNOS.  The males in clinical trials of citrulline and water melon, as a Viagra alternative, must lack L-arginine.
I think in autism the problem is lack of eNOS.
I thought L-citrulline might increase the positive effect of Agmatine that is very evident in Monty, aged 14 with ASD, but it has no additional effect.
Maybe some people do lack eNOS and l-arginine.
You do not need eNOS to make nitric oxide from the nitrites produced by beetroot juice.

Agmatine
We previously saw that the OTC supplement Agmatine increases eNOS, but it also actually affects BDNF.

Taken together, the findings of this study show that long-term agmatine administration increases the BDNF levels in both the hippocampus and amygdala, and also peripherally the NO synthesis and/or bioavailability, and corrects the age-related endothelial dysfunction, and hence may help in recovering vascular aging and vascular dementia.


Leukoaraiosis
Leukoaraiosis is a new word to this blog, it is very relevant to dementia, but it would likely only be relevant to autism if there has been hypoxia (lack of oxygen). Two readers of this blog do report hypoxia.
There is a lot of information in this blog about treating dementia and so for the sake of completeness I will elaborate further.
It appears that most people with Mild Cognitive Impairment (MCI) or dementia have lsome eukoaraiosis.
Leukoaraiosis also referred as ischemic demyelination or age-related white matter disease, is a radiological term given to white spots that appear on your MRI scan.

It is commonly observed in elderly people, and it is often a finding related to vascular dementia.  Histology from these lesions show atrophy of axons and decreased myelin. It is thought that localized hypoxia is what caused the damage.

On both CT and MRI, leukoaraiosis is characterized by bilateral patchy or confluent white matter changes.
So if your “autism” resulted from hypoxia, you might expect to see white spots on your MRI scan.
What is interesting is that leukoaraiosis may contribute to ongoing mild hypoxia.
It always seemed odd that people might benefit from HBOT (hyperbaric oxygen) years after they suffered acute hypoxia; but if the acute hypoxia left leukoaraiosis, perhaps this then reduces ongoing blood flow and thus leaves mild localized hypoxia, which does respond to treatment.
When blood flow is interrupted to part of the brain your doctor would call that a stroke.  A mini-stroke occurs when that blood flow is only temporarily interrupted.  These so-called transient ischemic attacks (TIA) are a warning sign of what may come shortly afterwards.
It appears in many people mini-strokes occur but remain unreported.
As a result of mini-strokes and/or leukoaraiosis perfusion in older people is not as good as in younger people and so cognition and memory suffer.
This can be partially addressed by making your blood more “slippery” using low dose aspirin, but the risk is that over the years blood vessels have narrowed and become brittle.  You then risk micro bleeds where the blood vessel cracks and the “slippery” blood can leak out.  This does happen in the brain
Cerebral microbleeds are not rare and are seen as another cause of cognitive impairment.





The conclusion for adults is that prevention is much better than cure. A diet rich in nitrates (spinach beetroot etc) and flavanols (cocoa etc) plenty of exercise and avoiding half a century of high cholesterol looks a wise choice. 

Emerging evidence suggests that silent strokes or lacunar infarctions, leukoaraiosis, and vascular diseases may be associated with cognitive impairment including dementia. We assessed the occurrence of these risk factors among various spectrum of cognitive dysfunction. A retrospective review of patients evaluated in Guam with the diagnosis of Memory Loss, Mild Cognitive Impairment (MCI) and Dementia from August 2006 to December 2014 was conducted. The history of stroke and co-morbid vascular diseases was identified. The neuro-imaging studies were reviewed to determine the presence of silent strokes and leukoaraiosis in patients without history of a clinical stroke. There were 585 patients included in the analysis. One hundred forty two patients having a diagnosis of memory loss, 95 have MCI and 348 have dementia. A history of stroke was present in 29% of patients with Memory Loss, 20% of patients with MCI and 30% of patients with dementia. Silent strokes without a history of clinical stroke were present in 10% of patients with memory loss and MCI, and 15% of patients with dementia. The presence of Leukoaraiosis was present in 50% of patients with memory loss, 56% of patients with MCI, and 60% of patients with dementia. Occurrences of vascular diseases were higher in patients with dementia than patients with Memory Loss and MCI. In conclusion, silent strokes, leukoaraiosis and vascular diseases are found to be more prevalent in patients with Dementia than those with Memory Loss and MCI.  

Oxygen deprived areas of the brain can change the way the brain functions in older adults. These areas of the brain were thought to be just a normal part of aging and could lead to other diseases such as Alzheimer's or stroke.
Leukoaraiosis is described as a condition where brain scans (CT or MRI) show bright white dots. These areas of the brain are deprived of oxygen and were considered to be a normal part of aging process.
"There has been a lot of controversy over these commonly identified abnormalities on MRI scans and their clinical impact. In the past leukoaraiosis has been considered a benign part of the aging process, like gray hair and wrinkles," said Kirk M. Welker, M.D., assistant professor of radiology in the College of Medicine at Mayo Clinic in Rochester, Minn., in a press release.
The condition is common in people who are above the age of 60. Recently, leukoaraiosis has been linked to diseases like Alzheimer's, hypertension and stroke.
"We know that aging is a risk factor for leukoaraiosis, and we suspect that high blood pressure may also play a role," Dr. Welker said.
Researchers from the Mayo Clinic obtained brain scans from 18 participants over the age of 60. The brain scans of these participants were matched against those obtained from a control group. Researchers found that these participants had lesions in the brain that were 25 millimeters long while some lesions in the brains of control group participants were about five millimeters long.
The participants were given tests based on words and visual patterns. All the participants were connected to brain scanners during the tests.
The participants of control group and study group completed the task with similar speed. However, researchers found that the brains of people who had moderate leukoaraiosis worked differently than people who had mild lesions.
They found that areas of brains that performed word-association tasks weren't activated during the test but areas that process visual patterns were highly activated.
"Different systems of the brain respond differently to disease. White matter damage affects connections within the brain's language network, which leads to an overall reduction in network activity," Dr. Welker said.
Welker said that diagnosing leukoaraiosis is important in people who are above 60, especially those who have to undergo brain surgery and those who are part of scientific research study.
Previous research shows that the probability of stroke increases with increase in leukoaraiosis spread.
"Our results add to a growing body of evidence that this is a disease we need to pay attention to Leukoaraiosis is not a benign manifestation of aging but an important pathologic condition that alters brain function," Welker said.  

Finally, now you know all about leukoaraiosis, back to beet root juice.


Background:
Exercise has positive neuroplastic effects on the aging brain. It has also been shown that ingestion of beet root juice (BRJ) increases blood flow to the brain and enhances exercise performance. Here, we examined whether there are synergistic effects of BRJ and exercise on neuroplasticity in the aging brain.
Methods:
Peak metabolic equivalent (MET) capacity and resting-state magnetic resonance imaging functional brain network organization are reported on 26 older (mean age = 65.4 years) participants randomly assigned to 6 weeks of exercise + BRJ or exercise + placebo.
Results:
Somatomotor community structure consistency was significantly enhanced in the exercise + BRJ group following the intervention (MBRJ = -2.27, SE = 0.145, MPlacebo = -2.89, SE = 0.156, p = .007). Differences in second-order connections between the somatomotor cortex and insular cortex were also significant; the exercise + BRJ group (M = 3.28, SE = 0.167) had a significantly lower number of connections than exercise + placebo (M = 3.91, SE = 0.18, p = .017) following the intervention. Evaluation of peak MET capacity revealed a trend for the exercise + BRJ group to have higher MET capacity following the intervention.
Conclusions:
Older adults who exercised and consumed BRJ demonstrated greater consistency within the motor community and fewer secondary connections with the insular cortex compared with those who exercised without BRJ. The exercise + BRJ group had brain networks that more closely resembled those of younger adults, showing the potential enhanced neuroplasticity conferred by combining exercise and BRJ consumption.  
BRJ is clearly an encouraging nutritional supplement that may improve functional health in older adults, and the proposed primary mechanism of benefit of BRJ is the rise in plasma nitrite caused by the high levels of dietary nitrate in BRJ (32). Consumed nitrate, once absorbed from the intestine, is taken up from the plasma by salivary glands and concentrated in saliva; nitrate is subsequently reduced to nitrite by oral bacteria and ultimately absorbed into the circulatory system (32,33). Nitrite appears to be reduced to NO during hypoxia. NO is an antioxidant and a potent vasodilator (34,35), is a critical relaxation factor synthesized in endothelial cells (36,37), and is key to vascular compliance. For this study, we hypothesized that reductions in brain blood flow associated with hypertension and aging associated leukoaraiosis result in low-grade hypoxia (38) and that these reductions might be offset by the NO-mediated vasodilation in hypoxic regions due to the increased amount of circulating nitrite from the BRJ ingestion. Indeed, results from our lab have shown that 24 hours of a high nitrate diet supplemented with a single dose of BRJ leads to increased regional CBF in older adults (39). Coupled with exercise (a hypoxia-inducing activity), we propose that the biological mechanism underlying the neural plasticity shown in Figure 1 resulted from increased NO bioavailability after drinking BRJ





Supplementation with nitrate (NO3)-rich beetroot juice has been shown to improve exercise performance and cardiovascular (CV) responses, due to an increased nitric oxide (NO) availability. However, it is unclear whether these benefits are greater in older adults who have an age-related decrease in NO and higher risk of disease. This systematic review examines 12 randomised, crossover, control trials, investigating food-based NO3 supplementation in older adults and its potential benefits on physiological and cognitive performances, and CV, cerebrovascular and metabolic health. Four studies found improvements in physiological performance (time to exhaustion) following dietary NO3 supplementation in older adults. Benefits on cognitive performance were unclear. Six studies reported improvements in CV health (blood pressure and blood flow), while six found no improvement. One study showed improvements in cerebrovascular health and two found no improvement in metabolic health. The current literature indicates positive effects of dietary NO3 supplementation in older adults on physiological performance, with some evidence indicating benefits on cardiovascular and cerebrovascular health. Effects on cognitive performance were mixed and studies on metabolic health indicated no benefit. However, there has been limited research conducted on the effects of dietary NO3 supplementation in older adults, thus, further study, utilising a randomised, double-blind, control trial design, is warranted.
  
Beet Root and Schizophrenia
Having read about cocoa and beet root a long time ago, I did try both on myself. I think beet root has effects that go well beyond lowering blood pressure.
There are of course no trials of beet root in autism, but there is one in the next closest thing, schizophrenia. Unfortunately it was in rats, but nonetheless the findings are interesting.
   
In recent years, there has been much focus on the apparent heterogeneity of schizophrenic symptoms. By contrast, this article proposes a unifying account emphasizing basic abnormalities of consciousness that underlie and also antecede a disparate assortment of signs and symptoms. Schizophrenia, is fundamentally a self-disorder or ipseity disturbance is  characterized by complementary distortions of the act of awareness, hyper reflexivity and diminished self-affection. Anxiety impacts people in ways that they are unaware. In the presence of anxiety, attention is highly directed towards threatening information. Recently, anxiety was found to impact task switching performance when threatening stimuli were present. In the current study, we examined the Anxiolytic and antipsychotic activity of Beet Root Juice (BRJ) in rats. This study reveals that the BRJ has showed decreased effects of turning behaviour, weaving behaviour, head bobbing and falling behaviour. It also showed decreased effect of loco motor activity and increase in catalepsy scoring. Thus it shows anti psychotic and anti anxiety effects.

Ketamine-Induced Stereotypic Behaviour in Mice
Animals were divided into five groups and each group consisted of four animals. The control animals received normal diet and treated with Ketamine (50 mg/kg) for 15 consecutive days. The animals of standard groups received Olanzapine (5 mg/kg) after 30 min Ketamine was given, (50 mg/kg) for 15 consecutive days. The animals of test groups received different concentrations of BRJ (2 , 4, 8% w/w) through a specially prepared diet and after 30 min Ketamine was given (50 mg/kg) for 15 consecutive days. Each rat was individually placed into plastic cages (37 × 24 × 30 cm3) divided into quadrants by lines on the floor and allowed to acclimatize for at least 30 min before the testing began. Behavioural tests were performed between 10 a.m. and 4 p.m. The stereotypic behaviour was assessed by counting the number of turning, weaving, head-bobbing and ataxia. Turning was measured by counting turn around every 15 min over 60 min. Weaving and head-bobbing were measured by counting its neck wave right and left, and go up and down every 15 min over 60 min. Ataxia was assessed by counting the number of falls of each rat on the floor of the cage every 15 min over 60 min period

Beet root juice was as effective as Olanzapine, an antipsychotic medication used to treat schizophrenia and bipolar disorder. (Ketamine is what creates the stereotypy)



Beet root juice was more effective than Haloperidol, a typical antipsychotic medication used in the treatment of schizophrenia, tics in Tourette syndrome and  mania in bipolar disorder


Beet root was as effective as Diazepam (aka Valium), is a medication of the benzodiazepine family that typically produces a calming effect 



I found the above paper very surprising. It certainly supports my feeling about the effects of beet root juice being beyond just lowering blood pressure. It definitely has a calming effect on me, so it is not just in rats.

Beetroot Juice for Autism?
Why not try just try it?
It does taste better when it is 25% apple juice and 75% beetroot.
You can also use freeze dried beetroot powder, which can be put in capsules.
It is not clear the amount of powder you need.
>150 ml a day of juice gives the exercise endurance effect and the calming (Diazepam) effect.  I would guess 2 or 3 fresh beet root would be equivalent.
Freeze dried beet root powder appears to remove 90% of the weight. So 3g of powder equals about 30g of beetroot.
Some people use a teaspoon of beetroot powder to control blood pressure. 
I expect there are studies on beetroot powder and blood pressure.
I concluded in Monty, aged 14 with ASD, that while Agmatine has a significant effect from the first day citrulline has no noticeable effect whatsoever (so no lack of L-arginine).  Having just read about the rats from Karimnagar, India in the above study I started offering Monty some of my beetroot juice. I have filled some large gelatin capsules with freeze dried beetroot, but it is not clear how much you would need.  Better to stick with the juice and see if it does anything.
Beet root is rich in betaine, which is also good for you.
I think Agmatine increases eNOS and also NO, by increasing dietary nitrate we make more nitrite which is available to make more NO as it gets depleted by oxidative stress (Reactive Oxygen Species). It looks like some people with autism have no shortage of L-arginine and so there is no effect from arginine or citrulline supplementation.
I think there is a rationale to consider Agmatine and Beetroot juice. We do have the surprising results from the schizophrenic rats, which do suggest there can be a benefit. 
I have to say that after a year of drinking 150ml of beetroot juice a day, I am a convert. You do get used to the taste. 
Beetroot, cinnamon and cocoa flavanols are quite potent potential non-drug therapies for dementia and not forgetting where you left your car keys.