Emerging research indicates that an abnormal gut microbiome is a predisposing factor in the development of neurodevelopmental disorders, including autism spectrum disorder (ASD).[2,3] A growing number of studies have found that children with ASD have a gut microbiome that differs from that found in neurotypical children, indicating a link between gut and brain function.[4-8]
Faecal microbiota transplant (FMT) is rapidly gaining attention for its potential application in ASD. The treatment, which involves transferring faecal matter from a healthy donor, has shown promise in the management of autism-related gastrointestinal (GI) symptoms and behaviours, according to a recent open-label clinical trial.
The trial, which involved a two-week vancomycin treatment and a bowel cleanse followed by an FMT for 18 participants, aimed to determine if transplanting a large number and diversity of commensal microbes from a healthy donor would be beneficial in managing behaviours and GI symptoms associated with ASD in children. The combination treatment, called microbiota transfer therapy (MMT), showed positive results.
A common comorbidity in children with ASD is chronic GI symptoms. At the 18-week mark after the treatment, an 80% reduction in GI symptoms was observed. The participants were evaluated again two years after the conclusion of the study and most participants reported an ongoing improvement in GI symptoms, with an average 58% reduction in the gastrointestinal symptom rating scale (GSRS) and 26% reduction in the amount of days they experienced abnormal stools.
Families of the participants noted a steady reduction of their child’s ASD-related symptoms since the 18-week check-in. Improvements were seen across all behaviour scales, except for the parent global impressions-III scores, which remained similar to scores noted at the end of the trial. The most significant improvement was seen in the professionally evaluated childhood autism rating scale (CARS) scores, with the severity of ASD at the two-year mark 47% lower than the baseline scores.
A positive correlation was seen between the percent changes in the GSRS scores and behaviour scales, suggesting that improved GI function, brought about by MMT, may ameliorate behavioural severity in children with ASD, or vice versa. This is consistent with findings from previous studies, with more research being required in order to determine the direction of influence.
The faecal bacterial diversity of 16 of the 18 participants was measured at the two-year point using 16S ribosomal RNA gene amplicon sequencing analysis. It was found that most of the children had maintained a higher diversity of gut bacteria than what was observed at the 18-week check-in. In some cases, the microbiome diversity was even greater at two years than it had been at week 18 following the treatment.
While this trial suggests that FMT has a clinically important role to play in the management of neurodevelopmental disorders, such as ASD, further long-term studies are required in order to add weight to the findings of this trial.
- Kang DW, Adams JB, Coleman DM, et al. Long-term benefit of microbiota transfer therapy on autism symptoms and gut microbiota. Scientific Reports 2019;9(1):1-9. [Source]
- Rogers GB, Keating DJ, Young RL, et al. From gut dysbiosis to altered brain function and mental illness: mechanisms and pathways. Molecular Psychiatry 2016;21(6):738-748. [Full text]
- Sharon G, Sampson TR, Geschwind DH, et al. The central nervous system and the gut microbiome. Cell 2016;167(4):915-932. [Full text]
- Finegold, S. M. et al. Pyrosequencing study of fecal microflora of autistic and control children. Anaerobe 2010;16(4):444-453. [Full text]
- De Angelis M, et al. Fecal microbiota and metabolome of children with autism and pervasive developmental disorder not otherwise specified. Plos One 2 2013;8(10):1-18. [Full text]
- Williams BL, Hornig M, Parekh T, et al. Application of novel PCR-based methods for detection, quantification, and phylogenetic characterization of Sutterella species in intestinal biopsy samples from children with autism and gastrointestinal disturbances. MBio 2012;3(1):1-11. [Full text]
- Gondalia SV, et al. Molecular characterisation of gastrointestinal microbiota of children with autism (with and without gastrointestinal dysfunction) and their neurotypical siblings. Autism Research 2012;5(6):419-427. [Abstract]
- Son JS, et al. Comparison of fecal microbiota in children with autism spectrum disorders and neurotypical siblings in the Simons simplex collection. Plos One 2015;10(10):1-19. [Full text]