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Showing posts with label Complex I. Show all posts
Showing posts with label Complex I. Show all posts

Wednesday, 16 October 2019

DMF for Mitochondrial Dysfunction in Autism and Friedreich's Ataxia?


Yet more money was just donated to autism research. In 2017 the CEO of Broadcom gave $20 million to MIT and now he has given $20 million to Harvard, where he did his MBA.




Time to boost Homer's mitochondria?


I think philanthropists from the fast-moving IT sector should demand rather more from the slow-moving world of autism research.  I also think common sense is often more lacking than money.

The US Government has also just announced $1.8 billion for autism research.

Donald Trump authorized a five-year extension of the Autism Collaboration, Accountability, Research, Education and Support (CARES) Act. The 2014 act dedicated funds to children with autism spectrum disorder, but the new version includes adults.  Children with autism do indeed grow up to become adults with autism. 
Today we look at further applications of DMF, which is a cheap chemical also sold as a very expensive drug.

We learnt from Dr Kelley, from Johns Hopkins, that most regressive autism features mitochondrial dysfunction. Mitochondria within cells produce ATP (fuel) via a complex multi-step process called OXPHOS. If you lack any of the required enzyme complexes for OXPHOS, that part of your body will suffer a power shortage/outage.  Another potential problem is just too few mitochondria.

The treatment for mitochondrial disease is mainly to avoid further damage, using antioxidants.  If you know which enzyme complex is lacking, you might try and target that.

We saw a long time ago in this blog that PGC-1α is the master regulator of mitochondrial biogenesis and as such this would be a target for people with mitochondrial dysfunction.

Among other interactions, PGC-1α is affected by something called PPAR-γ (Peroxisome proliferator-activated receptor gamma), also known as the glitazone receptor.

There are many cheap drugs that target PPAR-γ, because this is also one way to treat type 2 diabetes.  We saw that Glitazone drugs have been successfully trialed in autism.

Today we look at another way to activate PGC-1α and stimulate the production of more mitochondria and increase the necessary enzyme complexes for OXPHOS.

Many people with autism in the US are diagnosed by their MAPS/DAN doctor as lacking Complex 1.

DMF has two principal effects. It affects NRF2 and HCAR2.

Many supplements sold online are supposed to activate NRF2, but may well lack potency.

Activating NRF2 turns on your antioxidant defences and so is good for people with autism, diabetes, COPD and many other conditions, but is bad for someone with cancer.

We will see later how, somewhat bizarrely, at high doses DMF reverses function and causes cell death via oxidative stress, making it a potent potential cancer therapy.  Cancer cells are highly vulnerable to oxidative stress.

In this blog we are focusing on low doses of DMF, that are NRF2 activating.

In the chart below the NFE2L2 gene encodes the transcription factor NRF2. We want the antioxidant genes turned on.

We then get another benefit because NRF2 expression also regulates NRF1 expression.

The transcription factor NRF1 is another regulator of mitochondrial biogenesis with involvements in mitochondrial replication  and transcription of mitochondrial DNA.

We then get a third benefit from DMF via activating HCAR2, this time we increase Complex I expression.  In the OXPOS multistep process to make fuel/ATP the bottleneck is usually Complex I, so Complex I is often referred to as being “rate limiting”. Complex I is the most important deficiency to fix.









Dimethyl fumarate mediates Nrf2-dependent mitochondrial biogenesis in mice and humans



The induction of mitochondrial biogenesis could potentially alleviate mitochondrial and muscle disease. We show here that dimethyl fumarate (DMF) dose-dependently induces mitochondrial biogenesis and function dosed to cells in vitro, and also dosed in vivo to mice and humans. The induction of mitochondrial gene expression is more dependent on DMF's target Nrf2 than hydroxycarboxylic acid receptor 2 (HCAR2). Thus, DMF induces mitochondrial biogenesis primarily through its action on Nrf2, and is the first drug demonstrated to increase mitochondrial biogenesis with in vivo human dosing. This is the first demonstration that mitochondrial biogenesis is deficient in Multiple Sclerosis patients, which could have implications for MS pathophysiology and therapy. The observation that DMF stimulates mitochondrial biogenesis, gene expression and function suggests that it could be considered for mitochondrial disease therapy and/or therapy in muscle disease in which mitochondrial function is important.

                                                                                                                    
DMF for Friedreich's ataxia

Friedreich's ataxia (FA) is a genetic disease caused by mutations in the FXN gene on the chromosome 9, which produces a protein called frataxin. It causes difficulty walking, a loss of sensation in the arms and legs and impaired speech that worsens over time. Symptoms typically start between 5 and 15 years of age. Most young people diagnosed with FA require a mobility aid such as a wheelchair by their teens. As the disease progresses, people lose their sight and hearing. Other complications include scoliosis and diabetes.

Frataxin is required for the normal functioning of mitochondria, the energy-producing factories of cells. Mutations in the FXN gene lead to a decrease in the production of frataxin and the consequent disruption in mitochondrial function.
No effective treatment exists. FA shortens life expectancy due to heart disease, but some people can live into their sixties.


Friedreich’s Ataxia (FA) is an inherited neurodegenerative disorder resulting from decreased expression of the mitochondrial protein frataxin, for which there is no approved therapy. High throughput screening of clinically used drugs identified Dimethyl fumarate (DMF) as protective in FA patient cells. Here we demonstrate that DMF significantly increases frataxin gene (FXN) expression in FA cell model, FA mouse model and in DMF treated humans. DMF also rescues mitochondrial biogenesis deficiency in FA-patient derived cell model. We further examined the mechanism of DMF's frataxin induction in FA patient cells. It has been shown that transcription-inhibitory R-loops form at GAA expansion mutations, thus decreasing FXN expression. In FA patient cells, we demonstrate that DMF significantly increases transcription initiation. As a potential consequence, we observe significant reduction in both R-loop formation and transcriptional pausing thereby significantly increasing FXN expression. Lastly, DMF dosed Multiple Sclerosis (MS) patients showed significant increase in FXN expression by ~85%. Since inherited deficiency in FXN is the primary cause of FA, and DMF is demonstrated to increase FXN expression in humans, DMF could be considered for Friedreich's therapy.


High Dose DMF to treat some cancer

Some readers may recall that the protein DJ-1 is encoded by the Parkinson’s gene PARK7 and that DMF has already been proposed as a therapy for Parkinson’s disease. 

At high doses of DMF the protein DJ-1 loses its stabilization function and ends up effectively blocking NRF2. Put simply, high dose DMF turns off NRF2, making it a cancer cell killer.

Dimethyl Fumarate Controls the NRF2/DJ-1Axis in Cancer Cells: Therapeutic Applications

The transcription factor NRF2 (NFE2L2), regulates important antioxidant and cytoprotective genes. It enhances cancer cell proliferation and promotes chemoresistance in several cancers. Dimethyl fumarate (DMF) is known to promote NRF2 activity in noncancer models. We combined in vitro and in vivo methods to examine the effect of DMF on cancer cell death and the activation of the NRF2 antioxidant pathway. We demonstrated that at lower concentrations (<25 a="" activation="" antioxidant="" cytoprotective="" dmf="" has="" mol="" nrf2="" of="" pathway.="" role="" span="" the="" through=""> At higher concentrations, however (>25 μmol/L), DMF caused oxidative stress and subsequently cytotoxicity in several cancer cell lines. High DMF concentration decreases nuclear translocation of NRF2 and production of its downstream targets. The pro-oxidative and cytotoxic effects of high concentration of DMF were abrogated by overexpression of NRF2 in OVCAR3 cells, suggesting that DMF cytotoxicity is dependent of NRF2 depletion. High concentrations of DMF decreased the expression of DJ-1, a NRF2 protein stabilizer. Using DJ-1 siRNA and expression vector, we observed that the expression level of DJ-1 controls NRF2 activation, antioxidant defenses, and cell death in OVCAR3 cells. Finally, antitumoral effect of daily DMF (20 mg/kg) was also observed in vivo in two mice models of colon cancer. Taken together, these findings implicate the effect of DJ-1 on NRF2 in cancer development and identify DMF as a dose-dependent modulator of both NRF2 and DJ-1, which may be useful in exploiting the therapeutic potential of these endogenous antioxidants.







Proposed mechanism of DMF-induced cancer cell death. Low concentrations of DMF can induce the NRF2 antioxidant pathway, allowing NRF2 nuclear translocation and binding to the antioxidant response elements leading to the transcription of antioxidant and detoxifying enzymes, thereby promoting cell survival. High concentrations of DMF, however, induce disruption of the NRF2 stabilizer DJ-1, which in turn impairs NRF2 induction and transcriptional activities in response to DMF, induces ROS generation, GSH depletion, and hence, facilitates cancer cell death. Cys, cysteine; 2SC, succination of cysteine residues.


Conclusion

This post did not cost $20 million, it is yours for free.

It looks pretty obvious that people with autism caused by, or associated with, mitochondrial dysfunction might potentially benefit from DMF.

People with Friedreich’s Ataxia do not currently have any treatment options. Low dose DMF is free of side effects, the high doses used to treat Psoriasis and Multiple Sclerosis often cause troubling GI side effects.

DMF seems to have very many potential therapeutic applications, limited only by the cost of the pharmaceutical version of this cheap chemical. Fortunately the "autism dose" is tiny.


Related Earlier Posts







Wednesday, 3 October 2018

Ketones and Autism Part 6 - Capric Acid (C10) for Mitochondrial Disease, in Particular Complex 1, plus more on Metformin



Capric Acid (C10) is so named because it smells like a goat (Goat in Latin = Caper)
Photographer: Armin Kübelbeck, CC-BY-SA, Wikimedia Commons

Rather than Goaty acid, C10 is called Capric acid, or indeed Decanoic acid (after its 10 carbon atoms). Today’s post is indirectly again about ketones, because if you eat a Ketogenic Diet (KD) you are likely to consume a fair amount of Capric acid (C10).
I have written a lot in this blog about mitochondria, even though I do not think my son has mitochondrial dysfunction. Clearly many people with autism do have a lack of one or more of the critical mitochondrial enzyme complexes that allow glucose to be converted to ATP (usable energy), by the clever process OXPHOS (Oxidative phosphorylation).

The “rate limiting” enzyme is usually Complex 1, meaning that is the one it is most important not to be short of.
Another favourite, but obscure, subject of this blog is PPAR gamma.

Peroxisome proliferator-activated receptors (PPARs) are a group of proteins that function as transcription factors regulating the expression of certain genes. Transcription factors are particularly important because they trigger numerous effects.
PPAR gamma plays a key role in fat storage and glucose metabolism, but has other functions. 

Activation of PPAR-gamma by Capric acid (C10) has been shown to increase the number of mitochondria, increase the mitochondrial enzyme citrate synthase, increase complex I activity in mitochondria, and increase activity of the antioxidant enzyme catalase. 
So, if you have autism and impaired mitochondrial function, C10 may well give a benefit because it can increase the peak power available to your brain.


The Ketogenic diet (KD) is an effective treatment with regards to treating pharmaco-resistant epilepsy. However, there are difficulties around compliance and tolerability. Consequently, there is a need for refined/simpler formulations that could replicate the efficacy of the KD. One of the proposed hypotheses is that the KD increases cellular mitochondrial content which results in elevation of the seizure threshold. Here, we have focussed on the medium-chain triglyceride form of the diet and the observation that plasma octanoic acid (C8) and decanoic acid (C10) levels are elevated in patients on the medium-chain triglyceride KD. Using a neuronal cell line (SH-SY5Y), we demonstrated that 250-μM C10, but not C8, caused, over a 6-day period, a marked increase in the mitochondrial enzyme, citrate synthase along with complex I activity and catalase activity. Increased mitochondrial number was also indicated by electron microscopy. C10 is a reported peroxisome proliferator activator receptor γ agonist, and the use of a peroxisome proliferator activator receptor γ antagonist was shown to prevent the C10-mediated increase in mitochondrial content and catalase. C10 may mimic the mitochondrial proliferation associated with the KD and raises the possibility that formulations based on this fatty acid could replace a more complex diet. We propose that decanoic acid (C10) results in increased mitochondrial number. Our data suggest that this may occur via the activation of the PPARγ receptor and its target genes involved in mitochondrial biogenesis. This finding could be of significant benefit to epilepsy patients who are currently on a strict ketogenic diet. Evidence that C10 on its own can modulate mitochondrial number raises the possibility that a simplified and less stringent C10-based diet could be developed.

Capric Acid (C10) as a PPARγ agonist

As shown in the above study the mechanism by which C10 benefits the mitochondria is via PPARγ agonism.

Here is another study confirming that C10 is indeed a PPARγ agonist.


Background: Mechanism of action of medium chain fatty acid remains unknown.

Results: Our results show that decanoic acid (C10) binds and activates PPARγ.

Conclusion: Decanoic acid acts as a modulator of PPARγ and reduces blood glucose levels with no weight gain.

Significance: This study could lead to design of better type 2 diabetes drugs.


Other PPARγ agonists
PPARγ agonists have been covered previously in this blog and we know that glitazones, a class of drugs for diabetes, do improve some types of autism. Glitazones are PPARγ agonists.

Metformin, a very widely used drug for type 2 diabetes, works differently to Glitazones, but I did suggest a while back it should help some types of autism. Last year it was indeed found to be beneficial in Fragile X.


 "Basically, it's something like a wonder drug," Sonenberg said.
The study suggests that metformin might also be used to treat other autism spectrum disorders, said Ilse Gantois, a research associate in Sonenberg's lab at McGill.
"We mostly looked at the autistic form of behaviour in the Fragile X mouse model," explained Gantois, who is co-lead author with McGill researchers Arkady Khoutorsky and Jelena Popic. "We want to start testing other mouse models to see if the drug could also have benefits for other types of autism."

Metformin is very cheap and has been used in humans for 60 years. It is another example of re-purposing a drug from Grandpa’s medicine cabinet to treat Grandson’s autism. 

Metformin has been trialled to combat obesity in idiopathic autism caused by antipsychotics. It did help with weight gain, but no comments were made about behavioural improvements, but then those studied were on antipsychotic drugs, which might mask such effects. 
Glitazone-type drugs appear more problematic than Metformin.

There are natural PPAR gamma agonists and they are often used to lower cholesterol, lower blood sugar and improve insulin sensitivity.
Sytrinol, a product containing flavanols tangeretin and nobiletin does indeed have a positive effect on some people’s autism, but for most people (but not all) the effect is lost after a few days.

Our doctor reader Maja, did suggest combining it with a PPARα agonist to see if the effect might be maintained.
This combination has indeed been researched for type 2 diabetes.               

The effect of dual PPAR alpha/gamma stimulation with combination of rosiglitazone and fenofibrate on metabolic parameters in type 2 diabetic patients.


There actually is another natural substance that is an agonist of both PPARγ and PPARα, Berberine, the alkaloid long used in Chinese medicine.
In the research it is suggested that BRB localizes in mitochondria, inhibits respiratory electron chain and activates AMPK”, which is not what you would want. But this may not be correct.

People who like supplements might want to follow up on Berberine.
Berberine is used by many people with diabetes and a few with autism, for all kinds of reasons, from mercury to GI problems.

Berberine is a potent agonist of peroxisome proliferator activated receptor alpha.


Although berberine has hypolipidemic effects with a high affinity to nuclear proteins, the underlying molecular mechanism for this effect remains unclear. Here, we determine whether berberine is an agonist of peroxisome proliferator-activated receptor alpha (PPARalpha), with a lipid-lowering effect. The cell-based reporter gene analysis showed that berberine selectively activates PPARalpha (EC50 =0.58 mM, Emax =102.4). The radioligand binding assay shows that berberine binds directly to the ligand-binding domain of PPARalpha (Ki=0.73 mM) with similar affinity to fenofibrate. The mRNA and protein levels of CPT-Ialpha gene from HepG2 cells and hyperlipidemic rat liver are remarkably up-regulated by berberine, and this effect can be blocked by MK886, a non-competitive antagonist of PPARalpha. A comparison assay in which berberine and fenofibrate were used to treat hyperlipidaemic rats for three months shows that these drugs produce similar lipid-lowering effects, except that berberine increases high-density lipoprotein cholesterol more effectively than fenofibrate. These findings provide the first evidence that berberine is a potent agonist of PPARalpha and seems to be superior to fenofibrate for treating hyperlipidemia.


                                                                                                                                     

Sources of Capric Acid (C10)
Goat milk is a good source of capric acid.
Capric acid is 8-10% of coconut oil and 4% of palm kernel oil

Capric acid is a large component (about 40%) of the less expensive MCT oil supplements.


1.2. Fatty acid composition in goat milk fat Average goat milk fat differs in contents of its fatty acids significantly from average cow milk fat, being much higher in butyric (C4:0), caproic (C6:0), caprylic (C8:0), capric (C10:0), lauric (C12:0), myristic (C14:0), palmitic (C16:0), linoleic (C18:2), but lower in stearic (C18:0), and oleic acid (C18:1) (Table 1). Three of the medium chain fatty acids (caproic, caprylic, and capric) have actually been named after goats, due to their predominance in goat milk. They contribute to 15% of the total fatty acid content in goat milk in comparison to 5% in cow milk (Haenlein, 1993). The presence of relatively high levels of medium chain fatty acids (C6:0 to C10:0) in goat milk fat could be responsible for its inferior flavour (Skjevdal, 1979). 

             
Conclusion
If someone responds well to coconut oil or cheaper MCT oil the reason may have more to do with PPAR gamma and improved mitochondrial function than anything to do with ketones and what they do.
Cheaper MCT oils are mainly a mixture of C8 and C10. To maximize the production of the ketone BHB you really want just C8, but if what you really need is a PPAR gamma agonist, to perk up your mitochondria, it is the C10 you need.
You may indeed benefit from both ketones and agonizing PPAR gamma, in which case you either follow the Ketogenic Diet, or supplement BHB, C8 and C10.
I think this explains why some people with autism reportedly respond well to teaspoon-sized doses of cheaper MCT oil or small amounts of coconut oil.
If you have Complex 1 mitochondrial dysfunction then a dose of Capric acid (C10) is likely to help.
Berberine may, or may not be, as effective as C10. I doubt we will ever know. I think C10 is the better option. 
I wonder when the Canadian researchers will publish their results showing whether Metformin is beneficial beyond Fragile X syndrome. They do not really know why it helps, but that is a repeating theme in medicine.  It is a cheap safe drug, so it would be a pity to waste time finding out if it could be repurposed for some autism.



Friday, 1 June 2018

Autism, Power Outages and the Starving Brain?



There are certain Critical Periods in the development of the human brain and these are the most vulnerable times to any genetic or environmental insult.  Critical Periods (CPs) will be the subject of post appearing shortly.


Another power outage waiting to happen

 Have you wondered why autism secondary to mitochondrial disease (regressive autism) almost always seem to occur before five years of age, and usually much earlier?  Why does it not happen later? Why is it's onset often preceded by a viral infection?
I think you can consider much of this in terms of the brain running out of energy. Humans have evolved to require a huge amount of energy to power their developing brains, a massive 40% of the body’s energy is required by the brain in early childhood.  If your overload a power grid it will end in a blackout.
We know many people with autism have a tendency towards mitochondrial dysfunction, they lack some key enzyme complexes. This means that the process of OXPHOS (Oxidative phosphorylation), by which the body converts glucose to usable energy (ATP), is partially disabled. 

We saw in earlier posts how the supply of glucose and oxygen to the brain can be impaired in autism because there is unstable blood flow.


It is just like in your house, all your electrical appliances might mean you need a 25KW supply, because you do not use them all at the same time. Just to be on the safe side you might have a 40KW limit. What if the power company will only give you a 20 KW connection? If you turn on the clothes drier, the oven, the air conditioning and some other things all of a sudden you blow the main fuse and perhaps damage the hard drive of your old computer.
So, in the power-hungry brain of a three-year-old, you add a viral infection and all of a sudden you exceed the available power supply from the mitochondria, that have soldered on for 3years with impaired supply of complex 1 and imperfect cerebral blood flow. By the sixth year of life, the peak power requirement from the brain would have fallen to within the safe limit of the mitochondria and its impaired supply of complex 1.  Instead of blowing the fuse, which is easy to reset, you have blown some neuronal circuitry, which is not so easy to repair.    

Too Many Synapses?
We know that it is the synapses in the brain that are the big energy users and we also know that in most autism there are too many synapses. So, in that group of autism there is an even bigger potential energy demand.



Note that in Alzheimer’s type dementia (AD in the above chart) you see a severe loss of synapses/spines as atrophy takes place. This occurs at the same time as a loss of insulin sensitivity occurs (type 3 diabetes). Perhaps the AD brain is also starved of energy, it does seem to respond to ketosis (ketones replacing glucose as the fuel) and it responds to Agmatine (increasing blood flow via eNOS).
We also know that adolescent synaptic pruning is dysfunctional in autism and we even know why. Interestingly by modifying GABAA function with bumetanide we may indeed allow the brain to eliminate more synapses (a good thing), so possibly an unexpected benefit from Ben Ari’s original idea.

"Working with a mouse model we have shown that, at puberty, there is an increase in inhibitory GABA receptors, which are targets for brain chemicals that quiet down nerve cells. We now report that these GABA receptors trigger synaptic pruning at puberty in the mouse hippocampus, a brain area involved in learning and memory." The report, published by eLife, "Synaptic pruning in the female hippocampus is triggered at puberty by extrasynaptic GABAA receptors on dendritic spines."            
These findings may suggest new treatments targeting GABA receptors for "normalizing" synaptic pruning in diseases such as autism and schizophrenia, where synaptic pruning is abnormal. Research has suggested that children with autism may have an over-abundance of synapses in some parts of the brain.

Synaptic pruning in the female hippocampus is triggered at puberty by extrasynaptic GABAA receptors on dendritic spines

Adolescent synaptic pruning is thought to enable optimal cognition because it is disrupted in certain neuropathologies, yet the initiator of this process is unknown. One factor not yet considered is the α4βδ GABAA receptor (GABAR), an extrasynaptic inhibitory receptor which first emerges on dendritic spines at puberty in female mice. Here we show that α4βδ GABARs trigger adolescent pruning. Spine density of CA1 hippocampal pyramidal cells decreased by half post-pubertally in female wild-type but not α4 KO mice. This effect was associated with decreased expression of kalirin-7 (Kal7), a spine protein which controls actin cytoskeleton remodeling. Kal7 decreased at puberty as a result of reduced NMDAR activation due to α4βδ-mediated inhibition. In the absence of this inhibition, Kal7 expression was unchanged at puberty. In the unpruned condition, spatial re-learning was impaired. These data suggest that pubertal pruning requires α4βδ GABARs. In their absence, pruning is prevented and cognition is not optimal.


Strange Patterns of Growth
Longitudinal studies are when researchers collect the same data over long period of years. Most autism research is just based on a single snapshot in time.
One observation of mine is that some people with strictly defined autism (SDA) are born at the 90+ percentile for height, but then fall back to something like the 20 percentile. Body growth has dramatically slowed. Was this because energy has been diverted to the overgrowing brain? 
A five-year old’s brain is an energy monster. It uses twice as much glucose (the energy that fuels the brain) as that of a full-grown adult, a new study led by Northwestern University anthropologists has found.
It was previously believed that the brain’s resource burden on the body was largest at birth, when the size of the brain relative to the body is greatest. The researchers found instead that the brain maxes out its glucose use at age 5. At age 4 the brain consumes glucose at a rate comparable to 66 percent of the body’s resting metabolic rate (or more than 40 percent of the body’s total energy expenditure). 

“The mid-childhood peak in brain costs has to do with the fact that synapses, connections in the brain, max out at this age, when we learn so many of the things we need to know to be successful humans,” Kuzawa said.

“At its peak in childhood, the brain burns through two-thirds of the calories the entire body uses at rest, much more than other primate species,” said William Leonard, co-author of the study. “To compensate for these heavy energy demands of our big brains, children grow more slowly and are less physically active during this age range. Our findings strongly suggest that humans evolved to grow slowly during this time in order to free up fuel for our expensive, busy childhood brains.” 

Full paper: -


The high energetic costs of human brain development have been hypothesized to explain distinctive human traits, including exceptionally slow and protracted preadult growth. Although widely assumed to constrain life-history evolution, the metabolic requirements of the growing human brain are unknown. We combined previously collected PET and MRI data to calculate the human brain’s glucose use from birth to adulthood, which we compare with body growth rate. We evaluate the strength of brain–body metabolic trade-offs using the ratios of brain glucose uptake to the body’s resting metabolic rate (RMR) and daily energy requirements (DER) expressed in glucose-gram equivalents (glucosermr% and glucoseder%). We find that glucosermr% and glucoseder% do not peak at birth (52.5% and 59.8% of RMR, or 35.4% and 38.7% of DER, for males and females, respectively), when relative brain size is largest, but rather in childhood (66.3% and 65.0% of RMR and 43.3% and 43.8% of DER). Body-weight growth (dw/dt) and both glucosermr% and glucoseder% are strongly, inversely related: soon after birth, increases in brain glucose demand are accompanied by proportionate decreases in dw/dt. Ages of peak brain glucose demand and lowest dw/dt co-occur and subsequent developmental declines in brain metabolism are matched by proportionate increases in dw/dt until puberty. The finding that human brain glucose demands peak during childhood, and evidence that brain metabolism and body growth rate covary inversely across development, support the hypothesis that the high costs of human brain development require compensatory slowing of body growth rate. 

To quantify the metabolic costs of the human brain, in this study we used a unique, previously collected age series of PET measures of brain glucose uptake spanning birth to adulthood (32), along with existing MRI volumetric data (36), to calculate the brain’s total glucose use from birth to adulthood, which we compare with body growth rate. We estimate total brain glucose uptake by age (inclusive of all oxidative and nonoxidative functions), which we compare with two measures of whole-body energy expenditure: RMR, reflecting maintenance functions only, and daily energy requirements (DER), reflecting the combination of maintenance, activity, and growth. We hypothesized that ages of peak substrate competition (i.e., competition for glucose) between brain and body would be aligned developmentally with the age of slowest childhood body growth, and more generally that growth rate and brain glucose use would covary inversely during development, as is predicted by the concept of a trade-off between brain metabolism and body growth in human life-history evolution. 

Daily glucose use by the brain peaks at 5.2 y of age at 167.0 g/d and 146.1 g/d in males and females, respectively. These values represent 1.88- and 1.82-times the daily glucose use of the brain in adulthood (Fig. 1 A and B and SI Appendix, Fig. S2), despite the fact that body size is more than three-times as large in the adult.




Glucose use of the human brain by age. (A) Grams per day in males. (B) Grams per day in females; dashed horizontal line is adult value (A and B). (C) Glucosermr% (solid line) and glucoseder% (dashed line) in males. (D) Glucosermr% (solid line) and glucoseder% (dashed line) in females.

The most relevant data is the line highlighted in yellow below, showing brain consumption of glucose peaks at 40% (of total body consumption) around 5 years old and drops to 20% in adulthood.

Our findings agree with past estimates indicating that the brain dominates the body’s metabolism during early life (31). However, our PET-based calculations reveal that the magnitude of brain glucose uptake, both in absolute terms and relative to the body’s metabolic budget, does not peak at birth but rather in childhood, when the glucose used by the brain comprises the equivalent of 66% of the body’s RMR, and roughly 43% of total expenditure. These findings are in broad agreement with past clinical work showing that the body’s mass-specific glucose production rates are highest in childhood, and tightly linked with the brain’s metabolic needs (40). Whereas past attempts to quantify the contribution of the brain to the body’s metabolic expenditure suggested that the brain accounted for a continuously decreasing fraction of RMR as the brain-to-body weight ratio declined with age (25, 31), we find a more complex pattern of substrate trade-off. Both glucosermr% and glucoseder% decline in the first half-year as a fast but decelerating pace of body growth established in utero initially outpaces postnatal increases in brain metabolism. Beginning around 6 mo, increases in relative glucose use are matched by proportionate decreases in weight growth, whereas ages of declining brain glucose uptake in late childhood and early adolescence are accompanied by proportionate increases in weight growth. The relationships that we document between age changes in brain glucose demands and body-weight growth rate are particularly striking in males, who maintain these inverse linear trends despite experiencing threefold changes in brain glucose demand and body growth rate between 6 mo and 13 y of age. In females, an earlier onset of pubertal weight gain leads to earlier deviations from similar linear inverse relationships.
                                     

What the researchers then did was to see how the growth rate of the brain is correlated to the growth rate of the body. In effect that what they found was that the growth of the body has to slow down to allow the energy hungry brain to develop.  One the brain has passed its peak energy requirement at about 5 years old, body growth can then gradually accelerate. 
The brain is the red line, the body is blue. The chart on the left is males and the one on the right is females. 
So, we might suspect that in 2 to 4-year olds who seem not to be growing as fast as we might expect, the reason is that their brain is over-growing, a key feature of classic autism.

Glucoseder% and body-weight growth rate. Glucoseder% and weight velocities plotted as SD scores to allow unitless comparison. (A) Glucoseder% (red dots) and dw/dt (blue dots) by age in males. (B) Glucoseder% (red dots) and dw/dt (blue dots) by age in females


Brain Overgrowth in Autism
As has been previous commented on in this blog, Eric Courchesne has pretty much figured out what goes wrong in the growth trajectory of the autistic brain; that was almost 15 years ago.

Brain development in autism: early overgrowth followed by premature arrest of growth.


Author information


Abstract


Due to the relatively late age of clinical diagnosis of autism, the early brain pathology of children with autism has remained largely unstudied. The increased use of retrospective measures such as head circumference, along with a surge of MRI studies of toddlers with autism, have opened a whole new area of research and discovery. Recent studies have now shown that abnormal brain overgrowth occurs during the first 2 years of life in children with autism. By 2-4 years of age, the most deviant overgrowth is in cerebral, cerebellar, and limbic structures that underlie higher-order cognitive, social, emotional, and language functions. Excessive growth is followed by abnormally slow or arrested growth. Deviant brain growth in autism occurs at the very time when the formation of cerebral circuitry is at its most exuberant and vulnerable stage, and it may signal disruption of this process of circuit formation. The resulting aberrant connectivity and dysfunction may lead to the development of autistic behaviors. To discover the causes, neural substrates, early-warning signs and effective treatments of autism, future research should focus on elucidating the neurobiological defects that underlie brain growth abnormalities in autism that appear during these critical first years of life.


Research from 2017: -





Conclusion
A record of children’s height and weight and even head circumference is usually collected by their doctor. In an earlier post I did ask why they bother if nobody is checking this data. If a child falls from the 90th percentile in height to the 20th, something clearly is going on.
When I discussed this with a pediatric endocrinologist a few years ago, we then measured bone-age and IGF-1. If you have low IGF-1 and retarded bone age you might opt for some kind of growth hormone therapy.
In what is broadly defined as autism, I think we have some distinctly different things possibly happening: -

Group AMD
Energy conversion in the brain is less efficient than it should be due to a combination of impaired vascular function and impaired mitochondrial enzyme complex production. No symptoms are apparent and developmental milestones are achieved.  As the brain creates more synapses it energy requirement grows until the day when the body has some external insult like a viral infection, and the required power is not available, triggering a “power outage” which appears as the regression into autism. In biological terms there has been death of neurons and demyelination.

Group Sliding Down the Percentiles 
This group looks like a sub-set of classic autism. The brain grows too rapidly in the first two years after birth and this causes the expected slowing of body growth to occur much earlier than in typical children. This manifests itself in the child tumbling down the percentiles for height and weight.
The brain then stops growing prematurely, reducing energy consumption and allowing body growth to accelerate and the child slowly rises back up the height/weight percentiles.

Perhaps all those excessive synapses that were not pruned correctly are wasting glucose and so delay the growth of the rest of the body?   
In the sliding down the growth percentiles group, does this overgrowing brain ever exceed maximum available power? Maybe it just grows too fast and so mal-develops, as suggested by Courchesne, or maybe it grows too fast and cannot fuel correct development?  What happens if you increase maximum available power in this group, in the way some athletes use to enhance their performance/cheat?
All I know for sure is that in Monty, aged 14 with autism, increasing eNOS (endothelial nitric oxide synthase) using agmatine seems to make him achieve much more, with the same daily glucose consumption. I wonder what would happen if Agmatine was given to very young children as soon as it was noted that they were tumbling down the height percentiles?  This is perhaps what the pediatric endocrinologists should be thinking about, rather than just whether or not to administer growth hormones/IGF-1.
If you could identify Group AMD before the “power outage” you might be able to boost maximum power production or reduce body growth slightly and hence avoid the brain ever being starved of energy. That way you would not have most regressive autism.