Intranasal Insulin for Some Autism vs IGF-1 and NNZ-2566

 

Very often the simplest solutions are the best and very often, when fault finding a problem, people overlook the obvious.  

I seem to be forever having to mend things and I find this all the time.

Back in 2013, when I knew much less about autism, I wrote about the experimental use of insulin like growth factor 1 (IGF-1) in autism.  

It’s a Small World – IGF-1 and NNZ-2566 in Autism

It turned out that in autism the many different growth factors can be disturbed (too much, or too little) and this variation does indeed define some specific types of autism.  For example in Rett Syndrome there are very low levels of Nerve Growth Factor (NGF); low levels of NGF in some older people is the cause of their dementia.  In more common types of autism NGF is actually elevated.

IGF-1 is very well studied.

 

IGF-1 is a primary mediator of the effects of growth hormone (GH). 

Growth hormone is made in the anterior pituitary gland, is released into the blood stream, and then stimulates the liver to produce IGF-1. IGF-1 then stimulates systemic body growth, and has growth-promoting effects on almost every cell in the body, especially skeletal muscle, cartilage, bone, liver,kidney, nerves, skin, hematopoietic cell, and lungs. This would explain why adults abusing GH may end up needing hip and knee replacements.

Before getting into the science, IGF-1 has long been available as a drug to treat children with growth delays.  In the US this drug is being used on children with a type of autism called Phelan-McDermid Syndrome.

Now, regular readers will recall from my last post on intranasal insulin that it was in this very syndrome that there was a successful intranasal insulin.

So most likely without delving into the science at all it looks like IGF-1 and intranasal insulin are both options to treat the same dysfunction.

Using IGF-1

Clinical Trial in 22q13 Deletion Syndrome (Phelan-McDermid Syndrome)

Using Intranasal Insulin

Intranasal insulin to improve developmental delay in children with 22q13 deletion syndrome: an exploratory clinical trial.

NNZ-2566

This is an Australian drug that is a modified version of IGF-1 (a so called analog).  They modified it so that it can be taken orally rather than by injection.  The developer has a very thorough presentation showing why they think it should be effective in autism.  

  

NNZ-2566 - Rationale for use in Autistic Spectrum Disorders

The Science

The first thing to note is that insulin and IGF-1 act as messengers.  Disruption in growth factor signaling can have serious consequences.

Insulin and IGF-1 both activate the same insulin receptor (IR).

Most people think that insulin is a just a hormone produced in their pancreas that regulates the amount of glucose (sugar) in their blood.  It does of course do that, but it actually does much more.

  

Insulin receptors are expressed all over the body including the brain.

Here is a relatively simple presentation explaining the role of insulin signaling in the brain:-

The role of insulin receptor signaling in the brain

Now for the diehard scientists among you that have been reading about all those signaling pathways that lie behind autism, cancer and many other hard to treat conditions, look at the graphic below.

We know the importance of RAS.  Impaired RAS signaling underlies the RASopathies, one feature of which is cognitive loss (MR/ID), another is autism.

We also know the importance of Akt (PKB/protein kinase B) in some types of autism.  PTEN appears again.

So irrespective of an undoubtedly important effect on glucose and insulin resistance, we should expect activation of insulin receptors in the brain, in some types of autism, to have a further positive effect.

It would seem to be a potential therapy for RASopathies.

As is often the case, there are extreme dysfunctions of RAS and I suggest there are more mild dysfunctions.

I suggest that some people with autism and some cognitive dysfunction have a partial RASopathy.

Since autism contains both extremes of many dysfunctions, there will undoubtedly be types of autism that respond negatively, or not at all, to activation of insulin receptors in the brain.

Practicalities

Nobody likes injections and that is necessary to give IGF-1.

NNZ-2566 is an experimental autism drug and on past performance that means it will take decades to reach the market, if ever.

That leaves insulin which was sitting all along in your local pharmacy.

Intranasal insulin was once investigated for use in diabetics, but it did not work.  It is not absorbed into the blood stream.

This is of course the huge advantage for people with autism, since we only want to activate the insulin receptors in the brain.  If you are not diabetic why would you want to have any effects in the rest of the body?

Indeed there are known major side effects of injecting IGF-1 or GH (growth hormone) into adults.  All kinds of things start growing and this can lead to terrible results.

The fact that all the studies show that intranasal insulin does not enter the blood stream and so lower blood glucose levels, makes it a much better drug for autism than IGF-1 or indeed NNZ-2566.

Insulin

There are various types of insulin and the main difference is that some are modified to be longer acting.

The basic insulin is soluble or clear insulin, and nowadays is synthetic rather than derived from pigs.  Examples include Humulin Regular/R/S by Lilly.

The standard concentration is 100 IU/ml.

The trials in Alzheimer’s and other conditions varied in dosage but generally used about 20 to 40 IU per day.

This is not a trivial dose.  If injected, rather than inhaled, that dose would have a significant effect on lowering blood sugar and would be dangerous.

My antihistamine nasal spray gives a metered dose of 0.14 ml.

So without any dilution, if filled with off the shelf insulin it would dispense 14 IU per spray.

So no special high tech drugs, dilutants/diluents or dispensers appear to be necessary. Some trials do use fancy inhalers, like the one in the video at the end of this post.

To be prudent it might be wise to dilute the insulin so as to gradually increase the dose.  Maybe in some people the nasal membrane is more permeable than in others.  Some of the trials did this, but most did not.

A fridge is required, because insulin needs to be kept chilled.

I do wonder why nobody seems to be researching this in autism.  Silly point, as one insulin researcher commented on the earlier post; there is no big money to be made, hence no interest.

Insulin & Alzheimer’s

The reasons that intranasal insulin improves Alzheimer’s, and likely will Down Syndrome, may differ to those help in (some) autism.

Beta amyloid is key to Alzheimer’s (and early onset Alzheimer’s in Down Syndrome) but is not a known issue in autism.  Central insulin resistance is an issue in Alzheimer’s and might well be in autism.  

Perhaps people with mitochondrial dysfunction (an energy conversion dysfunction) might particularly benefit from increased glucose uptake in the brain.  It appears that mitochondrial dysfunction plays a role in insulin resistance. 

Role of Mitochondrial Dysfunction in Insulin Resistance

The activation of the RAS pathway might be highly beneficial to some people with autism.  

Here is a good film, which refers to the studies from previous posts and shows the effect on one man with Alzheimer's. 

Insulin and Alzheimer's (approx. 22 min.)

 You also see their fancy inhaler device.