Endogenous oxytocin levels in children with autism: Associations with cortisol levels and oxytocin receptor gene methylation.

Researchers measured oxytocin (a hormone linked to social bonding) in the saliva of children with and without autism. Children with autism had lower oxytocin levels in the morning and showed different stress responses throughout the day. While oxytocin normally helps manage stress in typical children, it appeared to work differently in children with autism, potentially making them more reactive to stress rather than protecting against it.

This study examined salivary oxytocin levels and oxytocin receptor gene methylation in 80 children with autism and 40 controls. Children with autism showed reduced morning oxytocin levels and altered stress responses compared to controls. In typically developing children, higher morning oxytocin was associated with lower afternoon cortisol, suggesting protective stress regulation. However, in autistic children, oxytocin increases from morning to afternoon were linked to higher stress-induced cortisol release, indicating a more reactive stress response.

No overall differences in oxytocin receptor gene methylation were found between groups, though controls showed associations between methylation patterns and cortisol levels.

Findings suggest oxytocin levels could serve as potential biomarkers for autism diagnosis and treatment monitoring. The altered oxytocin-stress relationships may inform development of interventions targeting the oxytocinergic system, though more research is needed to understand clinical applications.

Sample was predominantly male (4:1 ratio), limiting generalizability to females with autism. The study design and methodology are not clearly described in the abstract, making it difficult to assess potential confounding factors or methodological quality.

Alterations in the brain's oxytocinergic system have been suggested to play an important role in the pathophysiology of autism spectrum disorder (ASD), but insights from pediatric populations are sparse. Here, salivary oxytocin was examined in the morning (AM) and afternoon (PM) in school-aged children with (n = 80) and without (n = 40) ASD (boys/girls 4/1), and also characterizations of DNA methylation (DNAm) of the oxytocin receptor gene (OXTR) were obtained. Further, cortisol levels were assessed to examine links between the oxytocinergic system and hypothalamic-pituitary-adrenal (HPA) axis signaling. Children with ASD displayed altered (diminished) oxytocin levels in the morning, but not in the afternoon, after a mildly stress-inducing social interaction session.

Notably, in the control group, higher oxytocin levels at AM were associated with lower stress-induced cortisol at PM, likely reflective of a protective stress-regulatory mechanism for buffering HPA stress activity. In children with ASD, on the other hand, a significant rise in oxytocin levels from the morning to the afternoon was associated with a higher stress-induced cortisol release in the afternoon, likely reflective of a more reactive stress regulatory release of oxytocin for reactively coping with heightened HPA activity. Regarding epigenetic modifications, no overall pattern of OXTR hypo- or hypermethylation was evident in ASD. In control children, a notable association between OXTR methylation and levels of cortisol at PM was evident, likely indicative of a compensatory downregulation of OXTR methylation (higher oxytocin receptor expression) in children with heightened HPA axis activity.

Together, these observations bear important insights into altered oxytocinergic signaling in ASD, which may aid in establishing relevant biomarkers for diagnostic and/or treatment evaluation purposes targeting the oxytocinergic system in ASD.