UA-45667900-1
Showing posts with label metformin. Show all posts
Showing posts with label metformin. Show all posts

Monday 30 May 2016

Sense, Missense or Nonsense - Interpreting Genetic Research in Autism (TCF4, TSC2 , Shank3 and Wnt)




Some clever autism researchers pin their hopes on genetics, while some equally clever ones are not convinced.

One big problem is that genetic testing is still not very rigorous, it is fine if you know what you are looking for, like a specific single gene defect, but if it is a case of find any possible defect in any of the 700+ autism genes it can be hopeless.

Most of the single gene types of autism can be diagnosed based on known physical differences and then that specific gene can be analyzed to confirm the diagnosis.

Today’s post includes some recent examples from the research, and they highlight what is often lacking - some common sense.

There are numerous known single gene conditions that lead to a cascade of dysfunctions that can result in behaviors people associate with autism.  However in most of these single gene conditions, like Fragile X or Pitt-Hopkins, there is a wide spectrum, from mildly affected to severely affected.

There are various different ways in which a gene can be disturbed and so within a single gene condition there can be a variety of sub-dysfunctions.  A perfect example was recently forwarded to me, a study showing how a partial deletion of the Pitt Hopkins gene (TCF4) produced no physical features of the syndrome, but did unfortunately produce intellectual disability.

The study goes on to suggest that “screening for mutations in TCF4 could be considered in the investigation of NSID (non-syndromic intellectual disability)”

Partial deletion of TCF4 in three generation family with non-syndromic intellectual disability, without features of Pitt-Hopkins syndrome



This all matters because one day when therapies for Pitt Hopkins are available, they would very likely be effective on the cognitive impairment of those with undiagnosed partial-Pitt Hopkins.



Another reader sent me links to the studies showing:-


Rapamycin reverses impaired social interaction in mouse models of tuberous sclerosis complex.

Reversal of learning deficits in a Tsc2+/- mouse model of tuberous sclerosis.


But isn’t that Tuberous sclerosis (TSC) extremely rare? like Pitt Hopkins.  Is it really relevant?

Tuberous sclerosis (TSC)  is indeed a rare multisystem genetic disease that causes benign tumors to grow in the brain and on other vital organs such as the kidneys, heart, eyes, lungs, and skin. A combination of symptoms may include seizures, intellectual disability, developmental delay, behavioral problems, skin abnormalities, and lung and kidney disease. TSC is caused by a mutation of either of two genes, TSC1 and TSC2, 

About 60% of people with TSC have autism (biased to TSC2 mutations) and many have epilepsy.

How rare is TSC?  According to research between seven and 12 cases per 100,000, with more than half of these cases undetected.  

Call it 0.01%, rare indeed.

How rare is partial TSC?  What is partial TSC?  That is just my name for what happens when you have just a minor missense mutation, you have a mutation in TSC2 but have none of the characteristic traits of tuberous sclerosis, except autism.
In a recent study of children with autism 20% has a missense mutation of TSC2. 

Not so rare after all.


Mutations in tuberous sclerosis gene may be rife in autism


Mutations in TSC2, a gene typically associated with a syndrome called tuberous sclerosis, are found in many children with autism, suggests a genetic analysis presented yesterday at the 2016 International Meeting for Autism Research in Baltimore.
The findings support the theory that autism results from multiple ‘hits’ to the genome.
Tuberous sclerosis is characterized by benign tumors and skin growths called macules. Autism symptoms show up in about half of all people with tuberous sclerosis, perhaps due to abnormal wiring of neurons in the brain. Tuberous sclerosis is thought to result from mutations in either of two genes: TSC1 or TSC2.
The new analysis finds that mutations in TSC2 can also be silent, as far as symptoms of the syndrome go: Researchers found the missense mutations in 18 of 87 people with autism, none of whom have any of the characteristic traits of tuberous sclerosis.
“They had no macules, no seizure history,” says senior researcher Louisa Kalsner, assistant professor of pediatrics and neurology at the University of Connecticut School of Medicine in Farmington, who presented the results. “We were surprised.”
The researchers stumbled across the finding while searching for genetic variants that could account for signs of autism in children with no known cause of the condition. They performed genetic testing on blood samples from 87 children with autism.

Combined risk:

To see whether silent TSC2 mutations are equally prevalent in the general population, the researchers scanned data from 53,599 people in the Exome Aggregation Consortium database. They found the mutation in 10 percent of the individuals.
The researchers looked more closely at the children with autism, comparing the 18 children who have the mutation with the 69 who do not.
Children with TSC2 mutations were diagnosed about 10 months earlier than those without a mutation, suggesting the TSC2 mutations increase the severity of autism features. But in her small sample, Kalsner says, the groups show no differences in autism severity or cognitive skills. The researchers also found that 6 of the 18 children with TSC2 mutations are girls, compared with 12 of 69 children who don’t have the mutation.
TSC2 variants may combine with other genetic variants to increase the risk of autism. “We don’t think TSC is the sole cause of autism in these kids, but there’s a significant chance that it increases their risk,” Kalsner says.


"hyperactivation of the mechanistic target of rapamycin complex 1 (mTORC1) is a consequence of tuberous sclerosis complex (TSC) 1/2 inactivation."

"the combination of rapamycin and resveratrol may be an effective clinical strategy for treatment of diseases with mTORC1 hyperactivation."


So for the 20% of autism with partial TSC, so-called Rapalogs and other mTOR inhibitors could be helpful, but Rapalogs all have side effects.

One interesting option that arose in my earlier post on Type 3 diabetes and intranasal insulin is Metformin. The common drug used for type 2 diabetes.

 








Metformin regulates mTORC1 signaling (but so does insulin).

'Metformin activates AMPK by inhibiting oxidative phosphorylation, which in turn negatively regulates mTORC1 signaling via activation of TSC2 and inhibitory phosphorylation of raptor. In parallel, metformin inhibits mTORC1 signaling by suppressing the activity of the Rag GTPases and upregulating REDD1."

Source:  Rapalogs and mTOR inhibitors as anti-aging therapeutics



Clearly you could also just use intranasal insulin.  It might be less potent but should have less side effects because it acting only within the CNS (Metfornin would be given orally).



The Shank protein and the Wnt protein family

Mutations in a gene called Shank3 occur in about 0.5 percent of people with autism.  
But what about partial Shank3 dysfunction?

Shank proteins also play a role in synapse formation and dendritic spine maturation.

Mutations in this gene are associated with autism spectrum disorder. This gene is often missing in patients with 22q13.3 deletion syndrome

Researchers at MIT have just shown, for the first time, that loss of Shank3 affects a well-known set of proteins that comprise the Wnt signaling pathway.  Without Shank3, Wnt signaling is impaired and the synapses do not fully mature.


“The finding raises the possibility of treating autism with drugs that promote Wnt signaling, if the same connection is found in humans”

I have news for MIT, people already do use drugs that promote Wnt signaling, FRAX486 and Ivermectin for example.  All without any genetic testing, most likely.


Reactivating Shank3, or just promote Wnt signaling

The study below showed that in mice, aspects of autism were reversible by reactivating the Shank3 gene.  You might expect that in humans with a partial Shank3 dysfunction you might jump forward to the Wnt signaling pathway and intervene there.

Mouse study offers promise of reversing autism symptoms


One reader of this blog finds FRAX486 very helpful and to be without harmful side effects.  FRAX 486 was recently acquired by Roche and is sitting over there on a shelf gathering dust.



Where from here?

I think we should continue to look at the single gene syndromes but realize that very many more people may be partially affected by them.

Today’s genetic testing gives many false negatives, unless people know what they are looking for; so many dysfunctions go unnoticed.

This area of science is far from mature and there may be many things undetected in the 97% of the genome that is usually ignored that affect expression of the 3% that is the exome.

So best not to expect all the answers, just yet, from genetic testing; maybe in another 50 years.

Understanding and treating multiple-hit-autism, which is the majority of all autism, will require more detailed consideration of which signaling pathways have been disturbed by these hits.  There are 700 autism genes but there a far fewer signaling pathways, so it is not a gargantuan task.  For now a few people are figuring this out at home.   Good for them.

I hope someone does trials of metformin and intranasal insulin in autism.  Intranasal insulin looks very interesting and I was surprised to see in those earlier posts is apparently without side effects.

The odd thing is that metformin is indeed being trialed in autism, but not for its effect on autism, but its possible effect in countering the obesity caused by the usual psychiatric drugs widely prescribed in the US to people with autism.

My suggestion would be to ban the use of drugs like Risperdal, Abilify, Seroquel, Zyprexa etc.

Vanderbilt enrolling children with autism in medication-related weight gain study



Here are details of the trial.


Metformin will be dispensed in a liquid suspension of 100 mg/mL. For children 6-9 years of age, metformin will be started at 250 mg at their evening meal for 1 week, followed by the addition of a 250 mg dose at breakfast for 1 week. At the Week 2 visit, if metformin is well-tolerated, the dose will be increased to 500 mg twice daily. For children from 10-17 years of age, metformin will be started at 250 mg at their evening meal for 1 week, followed by the addition of a 250 mg dose at breakfast for 1 week. At the Week 2 visit, if metformin is well-tolerated, the dose will be increased to 500 mg twice daily. At the Week 4 visit, if metformin is well-tolerated, the dose will be increased to 850 mg twice daily.







Friday 25 March 2016

“Type 3” Diabetes in Alzheimer’s, but maybe also in some Autism



Intranasal insulin, for cognitive enhancement in Alzheimer’s and …



Today’s post was sparked by another little experiment of mine; no, not intranasal insulin.

Recently I have been using a reduced number of therapies on Monty, aged 12 with ASD.  Some people think there are just too many pills.

I wrote many posts last year about something called PPAR gamma (Peroxisome proliferator-activated receptor gamma, PPAR-γ or PPARG, also known as the glitazone receptor).

As you can read in Wikipedia:-

PPAR-gamma has been implicated in the pathology of numerous diseases including obesity, diabetes, atherosclerosis, and cancer. PPAR-gamma agonists have been used in the treatment of hyperlipidaemia andhyperglycemia. PPAR-gamma decreases the inflammatory response of many cardiovascular cells, particularly endothelial cells. PPAR-gamma activates the PON1 gene, increasing synthesis and release of paraoxonase 1 from the liver, reducing atherosclerosis.
Many insulin sensitizing drugs (namely, the thiazolidinediones) used in the treatment of diabetes target PPARG as a means to lower serum glucose without increasing pancreatic insulin secretion.

What we found out in earlier posts that PPAR-gamma can be used to reduce microglial activation, which should turn down the body’s “immunostat”.  A key feature of many people’s autism appears to be an over-activated immune system, reflected by activated microglia.


PPAR-gamma agonists as regulators of microglial activation and brain inflammation.


The present review summarizes the several lines of evidence supporting that PPAR-gamma natural and synthetic agonists may control brain inflammation by inhibiting several functions associated to microglial activation, such as the expression of surface antigens and the synthesis of nitric oxide, prostaglandins, inflammatory cytokines and chemokines. 
Although most of the evidence comes from in vitro observations, an increasing number of studies in animal models further supports the potential therapeutic use of PPAR-gamma agonists in human brain diseases including multiple sclerosis, Parkinson's disease and Alzheimer's disease.



Experiment

The potent PPAR-gamma agonist drugs like Rosiglitazone, have side effects which I think make them unsuitable for autism.  I use a flavanol called Tangeritin, in the form of a supplement called Sytrinol.

For two months we have not used Sytrinol, but yesterday Monty had one pill after lunch.

The piano lesson was great and then Monty had three hours with his Assistant, doing academic work and then some more piano practice.

Before she went home, Monty’s Assistant spent ten minutes telling me, and Monty’s big brother, just how great the afternoon had been.

“Monty was amazing today”

“When he was doing math, it was like he wasn’t autistic”

(we live in a country where autism means strict definition autism, what in the US is called severe autism)

“Did you hear how he played the piano?”

I told Monty’s brother to make a mental note of this and tell it to Mum/Mom later.

The next day the effect of Sytrinol was not as profound.

This actually is a recurring theme, the effect of various interventions is the greatest at the beginning  and then, as the body’s feedback loops get involved, the effect reduces.  

The same is true with cinnamon, another food-based intervention, that also helps people with diabetes.  The effect in (some) autism is greatest when you start.

It would be great if it was possible to keep the full initial effect of both Sytrinol and Cinnamon, and avoiding the dampening reaction caused by feedback loops.

I think if this is possible, it will be via targeting the therapy directly at the brain, rather than the entire body.  This can be achieved via the intranasal route, as used with oxytocin.

What to put in the spray?  This would be a very personalizable solution, since different people have different dysfunctions and to varying degrees.  Some possibilities might include:-

·        Insulin  (read on to learn why)
·        IGF-1
·        T3 thyroid hormone
·        TRH
·        Type 2 iodothyronine deiodinase (D2) 
·        Oxytocin
  
Fine tuning Cognition

It is difficult to be certain what therapy is responsible for what effect.

I recently told one researcher/parent that interventions in autism seem to take effect very quickly and so you can pretty rapidly run through a series of mini-trials to see what helps, what makes things worse and what does nothing.  Being a researcher, his view is that you need to try things for much longer.

One problem of trials lasting months is that external factors may then change, that cause behavior to change and distort the result. This is why I try to avoid trials from May to October, the allergy season.

Many people do find that some supplements help a lot for a week or two and then make things worse.  This includes things like some B vitamins and carnitine.  For other people continued use keeps giving a positive effect.


Previous Experience with Sytrinol

Monty’s assistant at school last year thought Sytrinol made him cleverer.

She also thought the PAK inhibiting propolis (BIO 30) had a similar effect.  This propolis is quite expensive and I concluded the effect was small and this might be because it just was not potent enough. 

One reader of this blog is using a much more potent PAK inhibitor, FRAX486, and some people in the US use Ivermectin.

Ivermectin is an anti-parasite drug which also happens to be a PAK inhibitor.  It is not suitable for long term use.



 Why would Sytrinol improve cognition?

I have written a lot about PPAR gamma in the past, so today has a new angle on the subject.

I did a quick check on PPAR gamma and cognition.

I was surprised what I found.

  


  

PPARγ Recruitment to Active ERK during Memory Consolidation Is Required for Alzheimer's Disease-Related Cognitive Enhancement



Cognitive impairment is a quintessential feature of Alzheimer's disease (AD) and AD mouse models. The peroxisome proliferator-activated receptor-γ (PPARγ) agonist rosiglitazone improves hippocampus-dependent cognitive deficits in some AD patients and ameliorates deficits in the Tg2576 mouse model for AD amyloidosis. Tg2576 cognitive enhancement occurs through the induction of a gene and protein expression profile reflecting convergence of the PPARγ signaling axis and the extracellular signal-regulated protein kinase (ERK) cascade, a critical mediator of memory consolidation. We therefore tested whether PPARγ and ERK associated in protein complexes that subserve cognitive enhancement through PPARγ agonism. Coimmunoprecipitation of hippocampal extracts revealed that PPARγ and activated, phosphorylated ERK (pERK) associated in Tg2576 in vivo, and that PPARγ agonism facilitated recruitment of PPARγ to pERK during memory consolidation. Furthermore, the amount of PPARγ recruited to pERK correlated with the cognitive reserve in humans with AD and in Tg2576. Our findings implicate a previously unidentified PPARγ–pERK complex that provides a molecular mechanism for the convergence of these pathways during cognitive enhancement, thereby offering new targets for therapeutic development in AD.


Cognitive Enhancementwith Rosiglitazone Links the Hippocampal PPAR gamma and ERK MAPK Signaling Pathways



Pathogenesis of Alzheimer’s and Diabetes

The pathogenesis of a disease is the biological mechanism (or mechanisms) that lead to the diseased state.

I am not suggesting that autism leads to Alzheimer’s.  (We do though know that most people with Down Syndrome will develop early Alzheimer’s in their 40s or 50s)

Many complex diseases like Alzheimer’s, cancer and indeed autism have multiple biological mechanisms behind them.

By studying the molecular pathways involved in one disease it may help understand another disease.  This is why some readers of this blog follow the cancer/oncology research.

For some time I have been intrigued at the overlap between diabetes and autism.  What is good for autism really does seem to be good for diabetes and vice versa.


Alzheimer’s Disease as Type 3 Diabetes

I was surprised to learn that some clinicians now consider Alzheimer’s Disease as Type 3 Diabetes.           

You will recall that Type 1 diabetes is when your pancreas packs up making insulin and then you have to inject yourself with supplementary insulin.

Type 2 diabetes occurs in late middle age, often linked to obesity, and is characterized by high blood sugar, insulin resistance (insulin sensitivity), and relative lack of insulin.

Insulin resistance (IR) is generally regarded as a pathological condition in which cells fail to respond to the normal actions of the hormone insulin. The body produces insulin. When the body produces insulin under conditions of insulin resistance, the cells in the body are resistant to the insulin and are unable to use it as effectively, leading to high blood sugar. Beta cells in the pancreas subsequently increase their production of insulin, further contributing to a high blood insulin level. This often remains undetected and can contribute to a diagnosis of Type 2 diabetes.  Despite the ill-effects of severe insulin resistance, recent investigations have revealed that insulin resistance is primarily a well-evolved mechanism to conserve the brain's glucose consumption by preventing muscles from taking up excessive glucose.[

Eventually Type 2 diabetes may progress to Type 1 diabetes mellitus, where the body's own immune system attacks the beta cells in the pancreas and destroys them. This means the body can no longer produce and secrete insulin into the blood and regulate the blood glucose concentration. We saw how the use of Verapamil can stop beta cells being destroyed.

Some clinicians/researchers propose that diabetes of the brain should be called Type 3 diabetes.

The research does support the view that Alzheimer’s does incorporate this brain-specific type of diabetes.  But I know wonder if this applies to some autism.




Alzheimer’s disease (AD) has characteristic histopathological, molecular, and biochemical abnormalities, including cell loss; abundant neurofibrillary tangles; dystrophic neurites; amyloid precursor protein, amyloid-β (APP-Aβ) deposits; increased activation of prodeath genes and signaling pathways; impaired energy metabolism; mitochondrial dysfunction; chronic oxidative stress; and DNA damage. Gaining a better understanding of AD pathogenesis will require a framework that mechanistically interlinks all these phenomena. Currently, there is a rapid growth in the literature pointing toward insulin deficiency and insulin resistance as mediators of AD-type neurodegeneration, but this surge of new information is riddled with conflicting and unresolved concepts regarding the potential contributions of type 2 diabetes mellitus (T2DM), metabolic syndrome, and obesity to AD pathogenesis. Herein, we review the evidence that (1) T2DM causes brain insulin resistance, oxidative stress, and cognitive impairment, but its aggregate effects fall far short of mimicking AD; (2) extensive disturbances in brain insulin and insulin-like growth factor (IGF) signaling mechanisms represent early and progressive abnormalities and could account for the majority of molecular, biochemical, and histopathological lesions in AD; (3) experimental brain diabetes produced by intracerebral administration of streptozotocin shares many features with AD, including cognitive impairment and disturbances in acetylcholine homeostasis; and (4) experimental brain diabetes is treatable with insulin sensitizer agents, i.e., drugs currently used to treat T2DM. We conclude that the term “type 3 diabetes” accurately reflects the fact that AD represents a form of diabetes that selectively involves the brain and has molecular and biochemical features that overlap with both type 1 diabetes mellitus and T2DM.

Altogether, the results from these studies provide strong evidence in support of the hypothesis that AD represents a form of diabetes mellitus that selectively afflicts the brain

The human and experimental animal model studies also showed that CNS impairments in insulin/IGF signaling mechanisms can occur in the absence of T1DM or T2DM

Altogether, the data provide strong evidence that AD is intrinsically a neuroendocrine disease caused by selective impairments in insulin and IGF signaling mechanisms, including deficiencies in local insulin and IGF production.

At the same time, it is essential to recognize that T2DM and T3DM are not solely the end results of insulin/IGF resistance and/or deficiency, because these syndromes are unequivocally accompanied by significant activation of inflammatory mediators, oxidative stress, DNA damage, and mitochondrial dysfunction, which contribute to the degenerative cascade by exacerbating insulin/ IGF resistance.

Some of the most relevant data supporting this concept have emerged from clinical studies demonstrating cognitive improvement and/or stabilization of cognitive impairment in subjects with early AD following treatment with intranasal insulin or  a PPAR agonist



Repurposing Diabetes Drugs for Brain Insulin Resistance in Alzheimer Disease


 Although many classes of drugs are now approved for management of diabetes, a primary focus of efforts to treat insulin-signaling dysfunction in AD has been the administration of exogenous insulin. There is abundant anecdotal evidence that insulin administration in people with diabetes may acutely affect mood, behavior, and cognitive performance.

Results of recent pilot studies of intranasal insulin in mild cognitive impairment (MCI) and AD have been encouraging. The most notable of these studies was a doubleblind, randomized trial of 104 older adults with MCI or AD who received placebo, low-dose (20 IU), or high-dose (40 IU) intranasal insulin for 4 months

In 2012, the U.S. National Institutes of Health allocated $7.9 million for a pivotal trial of intranasal insulin called the Study of Nasal Insulin in the Fight Against Forgetfulness (SNIFF; ClinicalTrials identifier: NCT01767909). This multicenter phase 2/3 study will be conducted by the ADCS. It is expected to recruit 250 participants with AD or MCI and to randomize them for 12 months to intranasal insulin or placebo, followed by an open-label extension of 6 months in which all participants will receive intranasal insulin. The study should be completed in late 2014.  The Study of Nasal Insulin in the Fight Against Forgetfulness (SNIFF)

In preclinical studies, TZDs improved biomarkers of AD as well as memory and cognition (31). The first pilot studies in humans were also generally encouraging, including a study by Watson et al. (32) that showed improved memory and modulation of amyloid-b levels in CSF compared with placebo after 6 months of treatment with rosiglitazone. On the basis of these preliminary studies, the maker of rosiglitazone sponsored two adequately powered phase 3 studies of rosiglitazone in AD as monotherapy or as adjunctive therapy to acetylcholinesterase inhibitors in mild to-moderate AD. These larger trials failed to replicate the positive findings of the smaller pilot studies (33).

Many explanations have been proposed for why rosiglitazone does not appear to be effective as a treatment for AD in cognitively impaired adults. Perhaps the most convincing explanation is that rosiglitazone has only modest blood-brain barrier penetration, and in fact, rosiglitazone is actively pumped out of the brain by an endogenous efflux system (34). Therefore, rosiglitazone should be expected to have only a mild insulin-sensitizing effect in the human brain.





   


Conclusion

The type 2 diabetes drugs like Rosiglitazone/Pioglitazone have been trialed in both autism and Alzheimer’s.  The results in autism with pioglitazone were positive, in Alzheimer’s they used Rosiglitazone, due to the adverse side effects of pioglitazone, and the results were very mixed.  Rosiglitazone has only modest blood-brain barrier penetration so it looks a poor choice.

In the autism trial they measured "autism" rather than cognitive function.

Effect of pioglitazone treatment on behavioral symptoms in autistic children 

In a small cohort of autistic children, daily treatment with 30 or 60 mg p.o. pioglitazone for 3–4 months induced apparent clinical improvement without adverse events. There were no adverse effects noted and behavioral measurements revealed a significant decrease in 4 out of 5 subcategories (irritability, lethargy, stereotypy, and hyperactivity). Improved behaviors were inversely correlated with patient age, indicating stronger effects on the younger patients.
Conclusion  Pioglitazone should be considered for further testing of therapeutic potential in autistic patients.

One to watch is the effect of the standard type 2 diabetes treatment Metformin on cognition in Alzheimer’s.  Nobody really knows the mode of action of Metformin.

Intranasal insulin is very interesting and not just in Alzheimer’s.


Intranasal insulin improves memory in humans


Intranasal Insulin as a Treatment for Alzheimer’s Disease: A Review of Basic Research and Clinical Evidence





I will add it to my growing list of therapies for mild cognitive impairment, in case I need it in the future.

·        Nerve growth factor (NGF) eye drops
·        Lions Mane Mushrooms (that increase NGF)
·        Cocoa Flavanols (increase cerebral blood flow)
·        Intranasal insulin or just Tangeritin/Sytrinol

I do not know if intranasal insulin would be a safe long-term therapy for children, but it would be a good diagnostic tool.  Once large numbers of older people start using intranasal insulin for cognition, we will find out how well it is tolerated.  Older people seem far more prone to side effects than younger people.


For now I think Tangeritin/Sytrinol is the best choice.