Nitric Oxide in Autism - nNOS as a precise target for treatment?

Today’s subject is not new to this blog, it is Nitric Oxide (NO) and how by reducing expression of the enzyme nNOS, which produces NO in neurons, you may reduce the severity of autism symptoms.  Monty has actually been reducing nNOS for several years using Agmatine.

The research is from Israel, which is better known for autism research into cannabis.

Several posts in this blog refer to NO:

https://www.epiphanyasd.com/search/label/Nitric%20Oxide

One introduces nitrosative stress, which is also covered in my book.

Nitrosative Stress, Nitric Oxide and Peroxynitrite

Nitric oxide performs many functions within the body.

I did make the graphic below a few years ago to show what happens to Arginine in the body and the role of my supplement Agmatine.

Arginine is converted to Nitric Oxide in the body by one of 3 enzymes (iNOS, eNOS and nNOS).

eNOS (endothelial nitric oxide synthase) will help expand blood vessels, lowering blood pressure and potentially boosting exercise endurance.

nNOS (neuronal nitric oxide synthase) is involved in the development of nervous system. It functions as a neurotransmitter important in long term potentiation and hence is likely to be important in memory and learning. nNOS has many other physiological functions, including regulation of cardiac function and peristalsis and sexual arousal in males and females.

iNOS (inductible nitric oxide synthase), involved in immune response, and produces NO as an immune defence mechanism, as NO is a free radical with an unpaired electron. It is the proximate cause of septic shock and may function in autoimmune disease.

 

I have used Agmatine as a supplement in my PolyPill for many years. It reduces iNOS and nNOS while increasing eNOS.

Note that you can use polyamines to induce autophagy and this idea is now used to improve cognition in people with dementia. Wheat seedlings and wheat germ are a rich source of polyamines and can simply be added to bread to make it counter some dementia.

 

Nitrosative stress

Nitrosative stress is the lesser known twin of oxidative stress. Both are generally bad for you (unless you have cancer, because cancer cells are vulnerable to it).

Nitrosative stress and oxidative stress both feature in most autism. The more severe the autism the higher the level of nitrosative stress.  Where there is nitrosative stress, expect to also see unusual amounts of NO.

Peroxynitrite from nitrosative stress can be quenched by Leucovorin, AKA calcium folinate. This is Dr Frye’s therapy for folate deficiency, but as I have mentioned previously it also has totally unrelated potential benefits. 

Now to see what the Israelis have been up to.

 

Israeli study reveals potential method for reducing symptoms of autism

Researchers find a direct link between levels of nitric oxide in the brain and condition in mice; reducing the amounts lowers indicators and behaviors. 

Researchers from the Hebrew University of Jerusalem have published a first-of-its-kind study revealing a potential future method for reducing the symptoms of autism among those diagnosed with the common developmental disorder.

Dr Haitham Amal and his team from the School of Pharmacy in the Faculty of Medicine discovered a direct connection between levels of nitric oxide (NO) in the brain and autism, the university said in a statement.

The study, conducted on mice and published Monday in the peer-reviewed Advanced Science journal, demonstrates that autism indicators increases as NO increases in the brain, and that autism indicators and behavior decrease as the levels of NO in the brains of murine models of autism are lowered “in a proactive and controlled manner.” 

 

“Our research showed – in an extraordinary way – that inhibiting the production of NO, specifically in brain neuron cells in mouse models of autism, causes a decrease in autism-like symptoms,” he said. “By inhibiting the production of NO on laboratory animals, they became more ‘social’ and less repetitiveness was observed in their behavior. Additionally, the animals showed interest in new objects and were less anxious. Finally, the decrease in NO levels led to a significant improvement in neuronal indices.”

 

Scientists identify a new molecular mechanism for autism - Advanced Science News

 

After having tested their hypothesis in living mice, the researchers turned their focus to cell cultures. To begin with, they cultured neuronal cells from normal and mutant mouse models. Increasing and decreasing levels of nitric oxide in these cultures led to similar biochemical changes as those seen in experiments with mice.

Having investigated the impact of nitric oxide in mice, Amal’s team sought to confirm their findings in humans. First, they tested neurons that were derived from the stem cells of people with mutations in the SHANK3 gene, living with ASD. These neurons had high levels of proteins that help diagnose stress caused by nitric oxide. When researchers treated these neurons with a nitric oxide inhibitor, the levels of these proteins subsided.

Thereafter, Amal’s lab measured the levels of the same proteins in samples of blood plasma taken from children with ASD. They wanted to validate their results in this demographic. Compared with unaffected children, those with ASD had higher levels of biomarkers that indicate nitric oxide stress.

Deeper analyses revealed that the production of numerous proteins responsible for neuronal development was increased or decreased, differing from their normal levels. Further, using computational analyses, the researchers found that genes involved in several mechanisms connected to ASD development were overrepresented. These genes are key to severing connections between neurons as well as driving inflammation and oxidative stress.

“This research is a significant breakthrough in autism research with the first direct connection made between an increase in the concentration of [nitric oxide] in the brain and autistic behavior,” said Amal. “I am hopeful that with our new understanding of the [nitric oxide] mechanism, we can begin to develop therapeutic drugs for ASD and help millions of children and adults living with autism around the world.”

Amal’s team is exploring the impact of nitric oxide in many more models of autism. “The good news is that we are exploring very similar data,” added Amal.

 

 

The NO Answer for Autism Spectrum Disorder

Autism spectrum disorders (ASDs) include a wide range of neurodevelopmental disorders. Several reports showed that mutations in different high-risk ASD genes lead to ASD. However, the underlying molecular mechanisms have not been deciphered. Recently, they reported a dramatic increase in nitric oxide (NO) levels in ASD mouse models. Here, they conducted a multidisciplinary study to investigate the role of NO in ASD. High levels of nitrosative stress biomarkers are found in both the Shank3 and Cntnap2 ASD mouse models. Pharmacological intervention with a neuronal NO synthase (nNOS) inhibitor in both models led to a reversal of the molecular, synaptic, and behavioral ASD-associated phenotypes. Importantly, treating iPSC-derived cortical neurons from patients with SHANK3 mutation with the nNOS inhibitor showed similar therapeutic effects. Clinically, they found a significant increase in nitrosative stress biomarkers in the plasma of low-functioning ASD patients. Bioinformatics of the SNO-proteome revealed that the complement system is enriched in ASD. This novel work reveals, for the first time, that NO plays a significant role in ASD. Their important findings will open novel directions to examine NO in diverse mutations on the spectrum as well as in other neurodevelopmental disorders. Finally, it suggests a novel strategy for effectively treating ASD.

 

 

NO Donor Administration Induced ASD-Like Behavior in WT Mice and Enhanced the ASD Phenotype in Mutant Mice 

NO Inhibition Reversed Synaptophysin Expression and Reduced Nitrosative Stress in Primary Cortical Neurons Derived from the Mutant Mouse Model 

nNOS Inhibition Restores the Expression of Key Synaptic Proteins Using iPSC-Derived Cortical Neurons from Patients with SHANK3 Mutations

Elevation of Nitrosative Stress Biomarker and Reprogramming of the SNO-Proteome in the Blood Samples of ASD Children

 

Our study is designed to examine the effect of high levels of NO on the development of ASD. This work shows that NO plays a key role in ASD. Importantly, this was confirmed in cellular, animal models, human iPSC-derived cortical neurons, as well as in clinical samples. Since the molecular mechanisms underlying ASD pathogenesis remain largely unknown, we provided a new mechanism that shows that NO plays a key role in ASD pathology at the molecular, cellular, and behavioral levels. An increase of Ca²⁺ influx in ASD pathology, including in human and mouse models of Shank3 and Cntnap2^(-/-), has already been reported. Ca²⁺ activates nNOS, which then leads to massive production of NO. Aberrant NO production induces oxidative and nitrosative stress, leading to increased 3-Ntyr production and aberrant protein SNO. Our data showed an increase in NO metabolites and 3-Ntyr production in both mouse models of ASD (Shank3^Δ4-22, Cntnap2^(-/-)). Increased 3-Ntyr was found in iPSC-derived cortical neurons from patients with SHANK3 mutations, SHANK3 knocked down in SHSY5Y cells, and in human ASD plasma samples. The elevated levels of 3-Ntyr in our study are consistent with previous postmortem examinations of ASD patients showing the accumulation of this molecule in the brain. 

Collectively, our results show for the first time that NO plays a key role in ASD development. We found that NO affects synaptogenesis as well as the glutamatergic and GABAergic systems in the cortex and the striatum, which converge into ASD-like behavioral deficits. This work suggests that NO is an important pathological factor in ASD. Examining NO in diverse mutations on the spectrum as well as other neurodevelopmental disorders and psychiatric diseases will open novel future research directions. Finally, this is a novel experimental study that establishes a direct link between NO and ASD, leading to the discovery of novel NO-related drug targets for the disorder and suggesting nNOS as a precise target for treatment.

 

The trigger for the excess NO production is put down to the increase of Ca²⁺ influx, which really is at the core of autism.  This was explained in the post about IP3R long ago. 

Is dysregulated IP3R calcium signaling a nexus where genes altered in ASD converge to exert their deleterious effect?

 

The simple answer appears to be YES.

 and in later posts:

https://www.epiphanyasd.com/search/label/IP3R

  

Conclusion

For autism a little less nNOS, please.

The researchers used the selective neuronal nitric oxide synthase inhibitor 7-nitroindazole.

Nitroindazole acts as a selective inhibitor for neuronal nitric oxide synthase, an enzyme in neuronal tissue, that converts arginine to citrulline and nitric oxide (NO).

7-Nitroindazole is under investigation as a possible protective agent against nerve damage caused by excitotoxicity or neurodegenerative diseases. It may act by reducing oxidative stress or by decreasing the amount of peroxynitrite formed in these tissues. These effects are related to the inhibition of type 1 nitric oxide synthase. However, anti-convulsive effect is derived from some other mechanisms. 

For older folks with higher blood pressure, a little more eNOS please; indeed, the explosive nitroglycerin is also used as a life-saving drug that induces eNOS production in someone about have a heart attack. The resulting NO widens blood vessels and so increases blood flow.

Methylene blue was mentioned in a recent comment in regard to nitric oxide (NO)

Methylene blue (MB) inhibits endothelial nitric oxide synthase (eNOS), inducible nitric oxide synthase (iNOS), guanylate cyclase, and cytokines such as tumor necrosis factor-α (TNF-α). MB restores vascular tone due to the selective blockade of both guanylate and iNOS.

MB should increase blood pressure.

Some people with autism respond well to MB. This likely is unrelated to its effect on NO and might well be due to its numerous anti-inflammatory effects (inhibiting NLRP3 inflammasome etc).

 

Methylene Blue - used for over a century in Psychiatry, also handy for your fish tank

According to the packaging:-

Effective against a range of fungal and bacterial infections

•          Increases the oxygen-carrying capacity of fish

•          Can be used as an antiseptic directly onto wounds

•          For use in tropical and cold water aquariums

 

Our reader Dragos recently let us all know about his success with very low doses of Methylene Blue (MB).  I think this came as a surprise to many, but actually there is nothing new about using this old pigment as a therapy in psychiatry.  Much is known about its modes of action.

 

What is Methylene Blue?

In 1876, German chemist Heinrich Caro synthesized methylene blue (MB) for the first time in history.  It was used as a dye for textiles. Around the same time, it was found that MB is capable of staining cells by binding to their structures, in addition, sometimes inactivating bacteria. This discovery prepared the way for biological or medical studies related to MB. Numerous scientists applied it to a variety of animal and bacterial studies, importantly Paul Ehrlich introduced it to humans in 1891 as an anti-malarial agent.

I was interested to see why it is used in aquariums, in particular the reference to increases the oxygen-carrying capacity of fish.

Methemoglobinemia (MetHb) is a rare blood disorder that affects how red blood cells deliver oxygen throughout your body.

A common way to treat  MetHb  in humans is to reduce methemoglobin levels using  Methylene blue (MB). Another common treatment, not surprisingly, is to give oxygen.

If you want to increase oxygen levels in the fish in your aquarium you put MB in the water.

More oxygen in your blood would improve exercise endurance meaning you would delay the point at which your mitochondria become unable to keep producing ATP efficiently.

I did some investigation and there is indeed a trend towards people using methyl blue to improve their sporting performance. It is mocked in some newspapers because it makes your tongue turn blue. It makes for good pictures on Instagram.     

The effect will be similar to those long distance cyclists who take beetroot juice, but the mechanism is different.

Be aware that just like beetroot may dye what comes out of your body bright red, MB may give you a hint of blue.

  

Improved Mitochondrial Function

One of the known effects of Methylene Blue (MB) is on the mitochondria.

In numerous papers it has been discussed how MB improves brain mitochondrial respiration.

In neurological disorders such as Alzheimer’s disease, traumatic brain injury, depression, stroke, Parkinson’s disease and some autism, mitochondria contribute to the disorder through decreased energy production and excessive production of reactive oxygen species (ROS).

This subject does get rather complex but in short methylene blue is able to perform alternative electron transport, bypassing parts of the electron transport chain.

In autism terms this means that some people diagnosed with a lack of Complex 1, 2, 3 or 4 in their mitochondria, might want to pay particular attention to how Methylene Blue might be helpful.

Improved mitochondrial function is another reason why sportsmen might want to use MB to enhance their performance.

As we have seen with other enhancing drugs like the Russian Meldonium, the US Diamox and the new US super ketone products, the military do end up using these products.  If you see a picture of a navy seal with a blue tongue you will know where it came from!

 

Methylene Blue inhibits Monoamine Oxidase (MAO)

MAOIs act by inhibiting the activity of monoamine oxidase, thus preventing the breakdown of monoamine neurotransmitters and thereby increasing their availability. There are two types of monoamine oxidase, MAO-A and MAO-B. MAO-A preferentially deaminates serotonin, melatonin, epinephrine, and norepinephrine. MAO-B preferentially deaminates phenethylamine and certain other trace amines; in contrast, MAO-A preferentially deaminates other trace amines, like tyramine, whereas dopamine is equally deaminated by both types.

Methyl blue is a reversible selective MAO-A inhibitor and so has antidepressant properties (it gives you more feel good serotonin). This interesting drug has several other pharmacological actions, including inhibition of nitric oxidase synthase (NOS), and guanylate cyclase and so its antidepressant properties should not be solely ascribed to inhibition of MAO-A. 

Inhibition of neuronal nitric oxide synthase and soluble guanylate cyclase prevents depression-like behaviour in rats exposed to chronic unpredictable mild stress

Beyond treating depression MAOIs (Monoamine oxidase inhibitors) have been found to be effective in the treatment of panic disorder, social phobia, mixed anxiety disorder and depression, bulimia, and post-traumatic stress disorder, as well as borderline personality disorder, and Obsessive Compulsive Disorder (OCD).

MAOIs appear to be particularly effective in the management of bipolar depression.

Methylene blue treatment for residual symptoms of bipolar disorder: randomised crossover study

Background: Residual symptoms and cognitive impairment are among important sources of disability in patients with bipolar disorder. Methylene blue could improve such symptoms because of its potential neuroprotective effects.

Aims: We conducted a double-blind crossover study of a low dose (15 mg, 'placebo') and an active dose (195 mg) of methylene blue in patients with bipolar disorder treated with lamotrigine.

Method: Thirty-seven participants were enrolled in a 6-month trial (trial registration: NCT00214877). The outcome measures included severity of depression, mania and anxiety, and cognitive functioning.

Results: The active dose of methylene blue significantly improved symptoms of depression both on the Montgomery-Åsberg Depression Rating Scale and Hamilton Rating Scale for Depression (P = 0.02 and 0.05 in last-observation-carried-forward analysis). It also reduced the symptoms of anxiety measured by the Hamilton Rating Scale for Anxiety (P = 0.02). The symptoms of mania remained low and stable throughout the study. The effects of methylene blue on cognitive symptoms were not significant. The medication was well tolerated with transient and mild side-effects.

Conclusions: Methylene blue used as an adjunctive medication improved residual symptoms of depression and anxiety in patients with bipolar disorder.

 

Methylene Blue activates oxidative stress response genes via Nrf2

One of the antioxidant effects of MB is activation of the redox switch Nrf2.  In the paper below it is also mentioned that MB has a beneficial against tau proteins. Amyloid and tau proteins clog up the brain in Alzheimer’s and as a result MB has been proposed as a therapy for dementia. 

Methylene blue upregulates Nrf2/ARE genes and prevents tau-related neurotoxicity

Methylene blue (MB, methylthioninium chloride) is a phenothiazine that crosses the blood brain barrier and acts as a redox cycler. Among its beneficial properties are its abilities to act as an antioxidant, to reduce tau protein aggregation and to improve energy metabolism. These actions are of particular interest for the treatment of neurodegenerative diseases with tau protein aggregates known as tauopathies. The present study examined the effects of MB in the P301S mouse model of tauopathy. Both 4 mg/kg MB (low dose) and 40 mg/kg MB (high dose) were administered in the diet ad libitum from 1 to 10 months of age. We assessed behavior, tau pathology, oxidative damage, inflammation and numbers of mitochondria. MB improved the behavioral abnormalities and reduced tau pathology, inflammation and oxidative damage in the P301S mice. These beneficial effects were associated with increased expression of genes regulated by NF-E2-related factor 2 (Nrf2)/antioxidant response element (ARE), which play an important role in antioxidant defenses, preventing protein aggregation, and reducing inflammation. The activation of Nrf2/ARE genes is neuroprotective in other transgenic mouse models of neurodegenerative diseases and it appears to be an important mediator of the neuroprotective effects of MB in P301S mice. Moreover, we used Nrf2 knock out fibroblasts to show that the upregulation of Nrf2/ARE genes by MB is Nrf2 dependent and not due to secondary effects of the compound. These findings provide further evidence that MB has important neuroprotective effects that may be beneficial in the treatment of human neurodegenerative diseases with tau pathology.

 

MB to treat inflammation and pain via sodium ion channels and iNOS

MB abates inflammation by suppressing nitric oxide production, and ultimately relieves pain in arthritis and colitis.  

MB suppresses the iNOS/NO-mediated inflammatory signaling by directly downregulating inducible NO synthase (iNOS).

Nitric oxide (NO) is a free radical which, in reactions with various molecules causes multiple biological effects, some good and some harmful.

It is produced by a reaction involving one of three enzymes iNOS, eNOS and nNOS.  i = inducible, n = neuronal and e = endothelial

iNOS is a major downstream mediator of inflammation.

eNOS is very helpful because it can widen blood vessels and so reduce blood pressure and increase blood flow.

nNOS is found in the brain and the peripheral nerve system where it has several important functions.  

MB may impede pain transmission by dampening neuronal excitability elicited by voltage-gated sodium channels (VGSCs).  You would then think that in people with seizures due to malfunctioning sodium channels, MB might be beneficial; for example Nav1.1 in Dravet syndrome. 

Methylene Blue Application to Lessen Pain: Its Analgesic Effect and Mechanism

Methylene blue (MB) is a cationic thiazine dye, widely used as a biological stain and chemical indicator. Growing evidence have revealed that MB functions to restore abnormal vasodilation and notably it is implicated even in pain relief. Physicians began to inject MB into degenerated disks to relieve pain in patients with chronic discogenic low back pain (CDLBP), and some of them achieved remarkable outcomes. For osteoarthritis and colitis, MB abates inflammation by suppressing nitric oxide production, and ultimately relieves pain. However, despite this clinical efficacy, MB has not attracted much public attention in terms of pain relief. Accordingly, this review focuses on how MB lessens pain, noting three major actions of this dye: anti-inflammation, sodium current reduction, and denervation. Moreover, we showed controversies over the efficacy of MB on CDLBP and raised also toxicity issues to look into the limitation of MB application. This analysis is the first attempt to illustrate its analgesic effects, which may offer a novel insight into MB as a pain-relief dye. 

Nicotinic acetylcholine receptors

The modulation of nicotinic acetylcholine receptors (nAChRs) has been suggested to play a role in the pathogenesis of various neurodegenerative diseases. 

MB acts as a non-competitive antagonist on α7 nAChRs.

Well known drugs that act in a similar way include the Alzheimer’s drug Memantine and Ketamine. Recall that intranasal Ketamine has been used in autism. 

Substances  with the opposite effect include nicotine, choline and of course

Amyloid beta, the marker of Alzheimer's disease.

Note that some people need to block α7 nAChRs and some people need to activate them. 

Methylene blue inhibits the function of α7-nicotinic acetylcholine receptors

FDA Drug Safety Communication: Serious CNS reactions possible when methylene blue is given to patients taking certain psychiatric medications

A list of the serotonergic psychiatric medications that can interact with methylene blue can be found here. 

• Methylene blue can interact with serotonergic psychiatric medications and cause serious CNS toxicity.
• In emergency situations requiring life-threatening or urgent treatment with methylene blue (as described above), the availability of alternative interventions should be considered and the benefit of methylene blue treatment should be weighed against the risk of serotonin toxicity. If methylene blue must be administered to a patient receiving a serotonergic drug, the serotonergic drug must be immediately stopped, and the patient should be closely monitored for emergent symptoms of CNS toxicity for two weeks (five weeks if fluoxetine [Prozac] was taken), or until 24 hours after the last dose of methylene blue, whichever comes first.
• In non-emergency situations when non-urgent treatment with methylene blue is contemplated and planned, the serotonergic psychiatric medication should be stopped to allow its activity in the brain to dissipate. Most serotonergic psychiatric drugs should be stopped at least 2 weeks in advance of methylene blue treatment. Fluoxetine (Prozac), which has a longer half-life compared to similar drugs, should be stopped at least 5 weeks in advance.
• Treatment with the serotonergic psychiatric medication may be resumed 24 hours after the last dose of methylene blue.
• Serotonergic psychiatric medications should not be started in a patient receiving methylene blue. Wait until 24 hours after the last dose of methylene blue before starting the antidepressant.
• Educate your patients to recognize the symptoms of serotonin toxicity or CNS toxicity and advise them to contact a healthcare professional immediately if they experience any symptoms while taking serotonergic psychiatric medications or methylene blue.

Conclusion 

Rather surprisingly, this therapy from the fish tank may have wide ranging effects on the autistic brain and in those with dementia, bipolar etc.

Possible benefits might include:

·        Improved production of ATP (energy) in the brain

·        Reduced oxidative stress in the brain

·        Reduced nitrosative stress

·        Reduced inflammation

·        Improved mood (due to increased serotonin)

·        Improved memory and cognitive function

·        Reduction in obsessive behaviors

In one of the papers, they comment that “methylene blue modulates functional connectivity in the human brain”.

It seems to work for Dragos.  You can also see that people on Reddit use it for issues like ADHD. 

 

Note the FDA warning:

Do not combine Methylene Blue with serotonergic psychiatric medications, because of the risk of serotonin syndrome (i.e., serotonin toxicity).

Hypoperfusion in Autism Revisited

One old post from this blog has been going viral recently (3,000 views in one day, via Facebook) and it is quite relevant to a debate that has been going on in the comments about the potential merits and mechanisms of Hyperbaric Oxygen Therapy (HBOT). Two commenters are big fans of HBOT.

Hypoperfusion is reduced blood flow, which is found in some people with autism and also in people with some types of dementia  

Having reread my old post I would recommend it to those who are looking into the treatment of brain damage caused by ischemia. 

Brain Hypoperfusion in Autism & Cocoa

While much in neuroscience is extremely complicated, there are some pretty basic things to consider that are not. Adequate blood supply is one of the basic issues and is something that can be improved.

You can increase blood flow by reducing vascular resistance, which means reducing the work the heart has to do to circulate blood around the body. As you reduce this resistance, blood pressure will fall, but that does not mean the flow rate of blood has reduced, it just means it is circulating more freely.

You can measure cerebral blood flow and this is how researchers know that it can be abnormal in autism.

As I noted in the old post above, HBOT is one therapy proposed by some. Using an MRI you could establish with certainty if HBOT was effective in any particular individual, in regard to increasing cerebral blood flow.

I think there will be many ways to improve perfusion in an affected individual. Without a particular type of MRI you cannot really know for sure if your case of autism is one of these.

The dementia research pointed me towards cocoa flavanols, which seem to affect nitric oxide (NO), but do not directly produce it.

Nitric oxide (NO) is very important in the body and one of its roles is vasodilation (widening of blood vessels).

Some people believe that nootropic drugs work by vasodilation, i.e. more blood flow increases cognitive function.  I think that this is one of many possible ways to improve cognition, which will work in some people, but not others. 

To understand Nitric oxide (NO) you have to go a little deeper and look at eNOS (endothelial nitric oxide synthase), iNOS (inducible NO synthase) and nNOS (neuronal NO synthase). Nitric oxide can be very good for you, but it can also be very bad for you.  The short version is that Nitric oxide (NO) production by endothelial nitric oxide synthase (eNOS) plays a protective role in maintaining vascular permeability, whereas NO derived from neuronal and inducible NOS is neurotoxic and can participate in neuronal damage occurring in ischemia.,

For a thorough explanation here is a highly cited paper:-

Nitric oxide synthases: regulation and function

Endothelial NOS (eNOS, NOS III) is mostly expressed in endothelial cells. It keeps blood vessels dilated, controls blood pressure, and has numerous other vasoprotective and anti-atherosclerotic effects. Many cardiovascular risk factors lead to oxidative stress, eNOS uncoupling, and endothelial dysfunction in the vasculature. Pharmacologically, vascular oxidative stress can be reduced and eNOS functionality restored with renin- and angiotensin-converting enzyme-inhibitors, with angiotensin receptor blockers, and with statins. 

Statins are already in my Polypill. Telmisartan seemed to be the most likely ACE inhibitor or ARB (angiotensin receptor blocker) to help some autism, when I reviewed them in a previous post. Telmisartan produced more singing, as does Agmatine (see below).

Now look at how NO is produced by eNOS:-

           https://en.wikipedia.org/wiki/Endothelial_NOS 

“In the vascular endothelium, NO is synthesized by eNOS from L-arginine and molecular oxygen, which binds to the heme group of eNOS, is reduced and finally incorporated into L- arginine to form NO and L-citrulline. The binding of the cofactor BH4 is essential for eNOS to efficiently generate NO. In the absence of this cofactor, eNOS shifts from a dimeric to a monomeric form, thus becoming uncoupled. In this conformation, instead of synthesizing NO, eNOS produces superoxide anion, a highly reactive free radical with deleterious consequences to the cardiovascular system.^”

BH4 (Tetrahydrobiopterin/Kuvan) is one of substances that comes up in autism research from time to time.  You would not want to be deficient in BH4 and if you have autism and BH4 deficiency you have a very obvious therapy.   

Biomarin’s Kuvan autism treatment faces reservations on the part of experts 

A good article, surprisingly from the UK Financial Times, which they ask not to be cut and paste, so I have not. Take a look.

If Kuvan lights up the brain, as Dr Frye suggested in the above FT article, I wonder what else can, in those people.  L-arginine might help, or perhaps its metabolite Agmatine, as used by our reader Tyler.

If you read the quite complicated paper below you will see that, in rats at least, Agmatine increases eNOS, while reducing  iNOS. 

You compare EC6 (experimental control after 6 hours) with Agm6 (Agmatine after 6 hours) and then EC24 with Agm24. 

Regulation of endothelial nitric oxide synthase by agmatine after transient global cerebral ischemia in rat brain

Effects of eNOS and iNOS expression by agmatine treatment following transient global ischemia in rat hippocampus. Representative expressional levels of eNOS (A) and iNOS (C) at 6 h after agmatine treatment (100 mg/kg, i.p), and densitometric data (B, D). Data represent means±SD for n=5/NC, n=3/EC and Agm group per each time point. ^*

Cost

BH4/Kuvan/Sapropterin is rather expensive, but people do use it off-label in autism.  It is the only FDA-approved medication for Phenylketonuria (PKU) to reduce blood Phe levels in patients with hyperphenylalaninemia (HPA) due to tetrahydrobiopterin (BH4-) responsive PKU.

http://www.biomarin.com/products/kuvan

PKU is one of those rare inborn errors of metabolism that lead to intellectual disability/MR and, not surprisingly, also autism. It is included in my Treatable ID tab at the top of every page.  The link will take you here  http://www.treatable-id.org/page36/Phenylketonuria.html

Agmatine is cheap and does have an almost immediate positive effect in some people with autism.

Do people who respond to BH4 respond to Agmatine and vice versa?

Agmatine does have many other modes of action, other than increasing eNOS and reducing iNOS.

I have been experimenting with Agmatine, and while Dr Frye suggests Kuvan can “light up the brain”, my impression of Agmatine brings the Energizer(US)/Duracell (Europe) Bunny to mind.

A daily dose of Agmatine is like having better battery in your toy bunny, at least in my house.  It is also associated with more singing.

Judging from Tyler’s comments perhaps he is seeing the same magnitude of effects that Dr Frye attributes to Kuvan.