Discoveries about the biological treatment of autism symptoms are growing and are hot topics for parents seeking solutions to assist their children. One area scientists have been looking into for some years with limited success is secretin as a treatment for symptoms of autism spectrum disorders (ASD).
The first study into the use of secretin for autism symptoms was conducted in 1998 and, since then, many scientists have looked into it in hopes that the hormone could be beneficial for autistic children.
This article turns to research to find out whether secretin can indeed be used as a treatment for some of the challenging symptoms associated with autism.
A brief overview of autism spectrum disorder
To understand the possible use of secretin for autism symptoms, it’s first useful to gain a general understanding of autism spectrum disorder (ASD).
Autism is a condition with several characteristic features, including difficulties with social and language skills, difficulty with social interactions, repetitive and restrictive behaviors, difficulty understanding social cues, and, for many, sensory challenges. Autistic disorders include pervasive developmental disorder (PDD), asperger’s syndrome, and others.
Children with autism are each different with a unique set of symptoms and no single cause or reason behind autism has been established. Because of this, biological, physiological, neurological, and genetic experts are actively engaged in research to hopefully find answers that help with the day-to-day experiences of autistic individuals and their families.
What is secretin?
Secretin is a gastrointestinal hormone (GI hormone) that was first considered in 1998 as a potential treatment for autism symptoms.
In short, gastrointestinal hormones are chemical messengers that regulate the physiological function of organs such as the intestine and pancreas. In addition, GI hormones also regulate secretion, gut motility, absorption, and digestion.
Secretin essentially has three main functions: namely the regulation of gastric acid, regulation of pancreatic bicarbonate, and osmoregulation in the duodenum (the part of the small intestines that connects the stomach) (DiGregorio & Sharma, 2021). Let’s break this down further:
Regulation of gastric acid secretion and pancreatic bicarbonate
This function is the most critical role of secretin. The gastric acid stimulates secretin release which allows for motility in the duodenum lumen. In turn, secretin causes more secretion of bicarbonate-rich pancreatic fluid. This process then neutralizes gastric H+ (plays a role in fat digestion by creating a neutral pH environment). Fatty acids in the duodenum also regulate the secretion of secretin.
Osmoregulation
Maintaining a steady water equilibrium (homeostasis) helps to ensure that the balance between water intake and excretion from the body is regulated. This is known as osmoregulation and this process is critical to maintaining the electrolyte balance of an organism.
Skipping the complicated reason why secretin plays a role in osmoregulation, all we really need to remember is that when the receptors in the cell detect elevated osmolality (osmotic concentration), secretin is released. This causes the release of vasopressin (regulates the ability of fluid around the cell to cause the cell to gain or lose water (tonicity) in the hypothalamus.
Secretin research also shows it plays a role in the regulation of GI mucosal growth (Rao, et.al., 2010). The mucosa refers to the inner lining of the intestinal tract and maintains the microbes in the intestinal lumen. Secretin plays a role in maintaining the GI’s mucosal growth.
The role of secretion is exceptionally vast. Secretin can be found in the synthetic form or in the porcine form (porcine secretin is most commonly used for autistic children). Synthetic secretin is developed in the laboratory while secretin porcine is the naturally occurring version.
What is secretin treatment for autism?
Many believe there is a link between autism spectrum disorder and gastrointestinal disorders and difficulties with the gut. It’s been shown that many children on the spectrum have issues with eating and seem to respond better to an anti-inflammatory diet.
In 1998, the efficacy of secretin as a treatment for autism was first highlighted in studies (Arehart-Treichel, 2002 & Williams, et al. 2012). The studies at the time found that children who had gastrointestinal disorders, as well as symptoms as seen in autism, showed improvements in their ASD symptoms. After being administered secretin, a behavior change was observed such as improved eye contact, alertness, and language.
Following this, secretin treatment for autism became popular but many subsequent studies have failed to replicate the result of the study. The first scientific study to test whether secretin injections help children with autism or not was reported in 1999 (Arehart-Treichel, 2002). The findings did not conclude that intravenous secretin (administered through the veins) helped autistic children perform better.
This finding came after a few test batteries consisting of behavioral tests, including the Autism Behavior Checklist, were done. The results compared participants who received the dose of secretin and those who received the placebo saline injection. Three subsequent scientific studies were published on secretin and, like other studies, failed to find positive results.
Even the study conducted by Molloy, et al. (2002) failed to support the initial hypothesis stating the study “found no significant difference between secretin and placebo treatment.” At this time, research on this is still being conducted.
What hormone deficiency is associated with autism?
Autism spectrum disorder is a neurodevelopmental disorder or condition with many possible causes, including hormonal imbalances. According to Abozaid, et al., there’s evidence that autistic children have altered plasma levels of growth hormone (GH) and ghrelin.
Both these hormones play a role in mucosal integrity and this is important for immune tolerance. Additionally, ghrelin also regulates neuroinflammatory (inflammatory) response in the brain or spinal cord) and apoptotic (a form of controlled cell death) processes (Abozaid, et al. 2020). If any of these processes are abnormal, they could be linked to the pathogenesis of autism.
How is secretin administered?
Secretin is found naturally in the mammalian organism but when studied for research purposes, secretin is administered intravenously (through the veins).
In 2001, Dr. Thomas Owley, an Assistant Professor of Child and Adolescent Psychiatry at the University of Chicago, administered an intravenous dose of porcine secretin as well as a saline intravenous dose on 56 autistic children aged three to 12 years old. The study found inclusive results, similar to many other studies. This study as well as many others have always administered secretin intravenously to look at its efficacy for treating autism symptoms.
In conclusion
It’s unknown to this date whether secretin plays a role in treating the symptoms of autism. Perhaps in the near future, as more findings are conducted, secretin may very well be used as a treatment for autism and other neurological conditions.
All we know for now is that secretin was initially (in 1998) considered as a potential intravenous treatment for symptoms such as language and behavior difficulties observed in autism spectrum disorder (ASD).
Biological studies have made great progress in research that dates back centuries, so there’s hope that, one day, secretin will have its play. For the time being, early intervention therapy is what’s usually recommended as a support for young autistic individuals.
References
Arehart-Treichel, J. (2002). Secretin Studies Fail to Show Efficacy in Autism Treatment. Psychiatric News: American Psychiatric Association, https://doi.org/10.1176/pn.37.1.0018
Abozaid, H.M., Algohary, E.A.A., Zaky, E.A., Mahmoud, R.A.A. (2020). Growth hormone and ghrelin status in autistic children, QJM: An International Journal of Medicine, 113(1), hcaa063.031, https://doi.org/10.1093/qjmed/hcaa063.031
DiGregorio N, Sharma S. (2021) Physiology, Secretin. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2021 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK537116/
Molloy, C.A., Manning-Courtney, P., Swayne, S. et al. (2002). Lack of Benefit of Intravenous Synthetic Human Secretin in the Treatment of Autism. J Autism Dev Disord 32, 545–551 https://0-doi-org.innopac.wits.ac.za/10.1023/A:1021202930206
Thomas, R.P, Hellmich, M.R., Townsend, C.M. Jr., Evers, B.M. (2003) Role of Gastrointestinal Hormones in the Proliferation of Normal and Neoplastic Tissues, Endocrine Reviews, 24, 5(1), 571–599, https://doi.org/10.1210/er.2002-0028
Synthetic human secretin, https://www.cancer.gov/publications/dictionaries/cancer-terms/def/synthetic-human-secretin
Rao, J.N., Wang, J.Y. (2010). Regulation of Gastrointestinal Mucosal Growth. San Rafael (CA): Morgan & Claypool Life Sciences, Role of GI Hormones on Gut Mucosal Growth. Available from: https://www.ncbi.nlm.nih.gov/books/NBK54093/
Williams, K., Wray, J. A., & Wheeler, D. M. (2012). Intravenous secretin for autism spectrum disorders (ASD). The Cochrane database of systematic reviews, 2012(4), CD003495.
