Proceedings of The Physiological Society

Europhysiology 2018 (London, UK) (2018) Proc Physiol Soc 41, PCB295

Poster Communications

Association of serotonin levels in urine with the autism severity.

A. Tomova1, H. Celusakova1, A. Kovac2, G. Repiska1, D. Ostatnikova1

1. Faculty of Medicine,Institute of Physiology, Comenius University in Bratislava, Bratislava, Slovakia. 2. Institute of Neuroimmunology, Slovak Academy of Sciences, Bratislava, Slovakia.

Autism-spectrum disorder (ASD) is a neurodevelopmental disorder characterized by deficits in social communication and repetitive patterns of behavior. However, most of the children with autism have gastrointestinal disorders (GI) and there is a correlation between the severity of autism manifestations and GI symptoms. Although the association between GI dysfunction and ASD behavior is not completely understood, research over the past years suggests that the gut-brain axis plays a critical role. Bidirectional communication between gut microbiome and the brain might be the responsible for at least some specific behavioral symptoms in people with ASD and serotonin is the possible signal molecule of this pathway. Serotonin pleiotropic effect across multiple brain systems is well known, it is a critical modulator of enteric and central nervous systems development and function. It has been shown on animal models that serotonin is associated with behavioral abnormalities. Recently a correlation between a quantitative measure of GI symptoms and whole blood serotonin levels was observed in children and adolescents with ASD. In order to assess the possible use of serotonin detection for diagnosis of autism or for establishing autism severity, we used the morning urine of 34 children with autism (age 6.39 ± 0.38 years) and 31 neurotypical children (age 6.88 ± 0.39 years). All children in autistic group were boys, 28 children in the control group were boys and three girls. Children with autism were recruited from the Autism Centre based at the Institute of Physiology, Comenius University in Bratislava, Faculty of Medicine. The protocol was approved by the Ethics Committee of the University. The study conformed to the code of ethics stated in the Declaration of Helsinki. Psychological evaluation of the children with autism was performed using ADIR and ADOS-2 scales. LC-MS/MS was used for serotonin detection. The results of the in our study revealed that children with autism had higher level of urine serotonin (0.1058 ± 0.0039 mmol serotonin/mmol creatinine) than children without (0.1014 ± 0.0058 mmol serotonin/mmol creatinine), although the difference was not significant (p = 0.26). Interestingly within the group of children with autism a significant association between the autism severity and serotonin levels was found. Children with more than 50% of the symptoms registered by ADOS-2 had significantly higher (0.1139 ± 0.0063 mmol serotonin/mmol creatinine) levels of serotonin, than children with less than 50% of the symptoms (0.09864 ± 0.0042 mmol serotonin/mmol creatinine) p = 0,024. Age difference in the groups was not significant 5.969 ± 0.61 vs 6.811 ± 0.49 years, p = 0.15. The results of our study support the hypothesis of association of serotonin levels with the autism manifestations, but only more complex study will reveal the mechanism of serotonin modulation of the gut-brain axis.

Where applicable, experiments conform with Society ethical requirements