Oxytocin - Not to be sniffed at?

Things seem to move slowly in the world of autism research.

Since the 1970s it has been discussed that oxytocin might be a wonder hormone that could make you feel better.  The problem was that it cannot cross the BBB (blood brain barrier).  Oxytocin secreted from the pituitary gland cannot re-enter the brain because of the BBB. Instead, the behavioral effects of oxytocin are thought to reflect release from centrally projecting oxytocin neurons, different from those that project to the pituitary gland.

Oxytocin is destroyed in the gastrointestinal tract, so must be administered by injection or as a nasal spray.  Because of the BBB any injected oxytocin should fail to enter the brain.  The nasal method of delivery uses the nasal membrane as a means of transferring the oxytocin.  But when it passes through that membrane it surely enters the blood and then will struggle to cross the BBB.  Note that most of oxytocin’s primary functions are outside of the brain; the ones relevant to autism however occur inside the brain.

For several years it was assumed that the nasal spray oxytocin could not possible affect behaviours, since it could not enter the brain.  This view now seems to be in question.  It seems fair to assume that either a small portion of the oxytocin manages to cross the BBB, or perhaps the BBB is indeed more permeable in some people.  There is a school of thought that believes that autism is caused by a BBB malfunction, and certain harmful substances that should have been kept out of the brain, were let in.  If this were indeed the case, perhaps that faulty BBB would also let the oxytocin in?

I had rather assumed that after 30-40 years, if there was some element of truth in the therapeutic value of oxytocin, it would have been proved by now.

The Good(ish) News

A five year study of the benefits of oxytocin nasal spray in autism will start this year in the US at some leading hospitals including Massachusetts General Hospital.  The study is managed by researcher Dr Linmarie Sikich, MD of the ASPIRE Research Program at the University of North Carolina-Chapel Hill.  The study will have 300 participants.

It is a follow-on study to one already completed by Dr Sikich and funded in part by Autism Speaks.  This initial study involved just 25 children, but seemed to have a positive outcome.

The Science Part

As I mentioned, there has been a great deal of research into Oxytocin.  Here is free paper called Social effects of oxytocinin humans: context and person matter.

A study was carried out in 2012 on adults with autism; the researchers did not seem to be that excited about the results, but suggested that the results warranted further studies.  The study is free to access:  Intranasal oxytocin versus placebo in the treatment of adults with autismspectrum disorders: a randomized controlled trial

A more typical study is this one:- Oxytocin, vasopressin and pair bonding: Implications for autism.  It sounds interesting, but in fact is more about the mating patterns of prairie voles vs. meadow voles.

In 2003 a study using an infusion of oxytocin vs. a placebo looked at the effects on repetitive behaviours:-  Oxytocin Infusion Reduces RepetitiveBehaviors in Adults with Autistic and Asperger’s Disorders

 
I wish these scientists would decide once and for all if oxytocin can cross the BBB.  If it cannot, then a huge amount of time and money is being wasted.

 

Conclusion

It seems that oxytocin spray does not appear to do harm.  It is already available over the counter (OTC) and indeed over the internet.  If you take too much oxytocin, some pretty strange things will start happening, since it is a hormone with many specific roles in the human body, other than making you feel good.

Some researchers and parents seem very impressed by its effects on autistic subjects.  Other scientists think it cannot possibly cross into the brain.

In five years’ time we should know conclusively whether it really does “work”.

 
I would put it in my plausible, but not proven, category. 

If you do try it at home, do let us all know the results.