Thursday, March 8, 2007

Secretin To Treat Autism Controversy

One of the currently controversial treatments for autism is the use of the neurotransmitter secretin. It was used to test pencreatic function in which capacity, amongst other things, it stimulated the pancreas to produce peptidase enzymes. According to one of the theories for the causation of autism ( the "opioid excess theory") substances with morphine like activity (peptides) can be derived from incomplete digestion of certain food, in particular casein, from milk and dairy produce, and gluten from wheat and some other cereals. These peptides can reach the brain and result in the range of symptoms which constitute autism. The peptidase enzymes resulting from the use of secretin will increase the breakdown of these substances and this will result in improvements in the symptoms of autism

The secretin used in the earliest studies, (from Ferrings) and in some of the current studies (Secrepan and Gaspretin) are derived from pigs and it would, therefore, differ slightly from the human product. Fears were raised that the foreign nature of the secretin could result in the production of antibodies to the secretin from the subject or following infusion but there is little evidence, to date, that this is, in fact, of clinical significance. A synthetic (pig) product, (Secrelux), is now available and is probably considerably purer than the pig derived material. It will be some time, probably over a year, before the biotechnologically derived variety, very pure and fully tested, appears on the market (assuming it satisfies the regulatory authorities).

So how did a protein that's used by the body in the digestive process end up being touted as an effective treatment for autism?

First, you need to know that many children with disorders in the autism spectrum also have digestive and intestinal disorders, and research has shown that a lot of those have deficiencies of secretin and other proteins used in digestion. In 1998, doctors from Maryland published an article in the Journal of the Association for Academic Minority Physicians about three children with autistic spectrum disorders. Within five weeks of receiving intravenous infusions of secretin to help regulate their digestion, all three showed "a dramatic improvement in their behavior, manifested by improved eye contact, alertness, and expansion of expressive language."

The intestinal hormone secretin, considered by some to be a promising drug in the treatment of autism, does not improve the symptoms and should not be used to treat the disorder, according to a new review of studies.

By October of 1998, the National Institutes of Health had posted their position on the use of secretin to treat autism - which essentially said that it does not have an official position. Specifically, the letter states that any use other than for gastro-intestinal treatment is considered an 'off-label' use, for which there have been no safety or efficacy (effectiveness) studies.

It goes on to state, however, that there has been one small safety study that seems to suggest that a single dose treatment of secretin is safe, in that it has no unwanted side effects, and invites researchers to submit applications for funding research.

That wasn't the last word, however. All over the country, parents of children with autism spectrum disorders are still reporting significant improvements in speech, behavior and attention in children who are given secretin. Because so little is know about the causes of autism, there is a possibility that there is a specific sub-group of children with autism who may benefit from the use of secretin. Currently, it is not a recommended treatment for autism in general. Those who advocate its use suggest that it be used in the specific sub-group of children who might benefit from its approved use - to treat gastrointestinal disorder.

In recent months, some politicians and patients have also suggested that a mercury compound called thimerosal, formerly used as a preservative in vaccines, may be one of the culprits behind autism. Although the purported connection has been well publicized, the Institute of Medicine concluded earlier this year that there is no evidence of a link between vaccines and autism.

Autistic disorders are probably caused by a combination of genetic, environmental and brain development factors. Unfortunately, there is still much ignorance about the safety and usefulness of secretin and it is to be hoped that the mists will clear soon. The serious side-effects prophesied in some quarters have not materialised but, at the same time, the benefits have been less spectacular than the early reports in the press and on television had led us to expect. In the meantime, parents and physicians must make their own choices based upon limited knowledge and understanding. It is to be hoped and anticipated that this situation will improve over the coming months.

Even if it eventually transpires that there are only a few who will benefit from the use of secretin, it will have been worthwhile. The secretin story has also caused many researchers to focus on the body as a whole and to treat the person with autism holistically rather then to concentrate solely on the perceived behavioural and psychological abnormalities.

No comments: