Probiotic and nasal oxytocin combination therapy improves autonomic function in autistic children

The study's findings, published in the Journal of Psychiatric Research, revealed a significant correlation of autonomic parameter changes with oxytocin (OT) level, severity scores, and ASD core symptoms at baseline and with the combination therapy course.

Autism spectrum disorder is a developmental and neurological disorder characterized by communication difficulties, repetitive behaviours, and restricted interest. It is reported to affect 1 in 44 children in the US, according to CDC estimates. However, the cause of autism is still not well understood and there is no availability of curative treatment.

In patients with ASD, autonomic dysfunction has been widely studied; however, response to probiotic and oxytocin combination intervention has not been investigated.

Xue-Jun Kong, Massachusetts General Hospital, Charlestown, MA, USA, and colleagues, therefore, conducted the study including 35 individuals with autism spectral disorder aged 3–20 years to explore autonomic responses to daily Lactobacillus plantarum probiotic supplementation and OT nasal spray treatment both alone and in combination.

The study led to the following findings:

· Significant improvements were identified in autonomic indices from subjects receiving combination treatment relative to those receiving placebo.

· Parameters that were observed to improve following combination treatment are time domain metrics of heart rate variability (HRV), including standard deviation of normal-to-normal R–R intervals (SDNN), the root mean square of successive differences between normal heartbeats (RMSSD), and proportion of the number of pairs of adjacent NN intervals that differ by more than 50ms (pNN50).

· Those that received either probiotics or OT alone showed fewer changes in RMSSD, pNN50, and SDNN.

· Several parameters that demonstrated significant improvements in combination therapy were found to be correlated with baseline levels of OT (LF power: r = −0.86; mean HR: r = 0.89).

· Social Responsiveness Scale (SRS) raw total scores (mean HR, r = 0.86) and Aberrant Behavior Checklist (ABC) raw total scores (mean HR r = 0.94) were correlated with mean heart rate (HR) and HRV-derived parameters.

"Our findings provide evidence of synergy of probiotic and oxytocin combination and a better understanding of the role of the gut-brain axis in ASD phenotypes and pathogenesis," the researchers wrote.

"Despite such promising preliminary findings, the underlying mechanisms and causal relationships of such synergistic effects remain elusive and require further investigation in large-scale and well-designed trials," they concluded.

Reference:

Kong, X., Kang, J., & Liu, K. (2023). Probiotic and intra-nasal oxytocin combination therapy on autonomic function and gut-brain axis signaling in young children and teens with autism spectrum disorder. Journal of Psychiatric Research. https://doi.org/10.1016/j.jpsychires.2023.08.006