The paper by Dae-Wook Kang and colleagues [1] (open-access) has already been picked up by some media (see here) and it seems, also has a following from likely proponents and detractors particularly on social media. Including one James Adams on the authorship list, someone who is quite well-known in autism research circles (see here and see here for examples) alongside some other notable inclusions (Alessio Fasano, Thomas Borody, etc), the authors describe the results of small open-label study - I repeat, a small open-label trial - of 18 participants diagnosed with an autism spectrum disorder (ASD) who underwent a 10-week program characterised by the use of antibiotics, a bowel cleanse and then regular poo transplants for approximately 8 weeks. Additional information about the study and its results can be found here or if you wish, you can see the ClinicalTrials.gov entry here.
Tapping into a growing interest in how the gut (and its contents) might be important for at least some autism (see here for example) the aims of the trial were to "follow gut microbiota in healthy and treated children with ASD longitudinally as well as to evaluate an investigational new treatment, MTT [Microbiota Transfer Therapy], for its effectiveness in children with ASD in treating both GI [gastrointestinal] symptoms (primary outcome) and ASD-related symptoms (secondary outcomes), and to determine the effect of MTT on the gut microbiome."
The study included children diagnosed on the autism spectrum - ADI-R diagnosed - aged between 7-16 years old. All presented with moderate to severe functional bowel issues alongside their autism (something not unusual it seems). The authors also report using a control group of "20 age- and gender-matched neurotypical children without GI disorders" who were monitored but not treated as part of their study design.
The study first involved the administration of the antibiotic vancomycin for 2 weeks (something that has, on its own, some peer-reviewed research history with autism in mind [2]) used to 'profoundly suppress' pathogenic bacteria. Prilosec, the brand name for omeprazole was also administered towards the end of the bacterial washout phase initiated by the use of vancomycin. Prilosec is a medicine traditionally used to suppress stomach acid secretions and was used to "remove most remaining gut bacteria and vancomycin" and aid the passage and survival of the donor stool to the wider gastrointestinal (GI) tract. I say all that knowing that such medicines can affect the composition of the gut microbiota. Then came the bowel cleanse (Moviprep) complete with a fasting from food day, followed by the main [research] event: oral or rectal administration of donor stool and an initial high dose followed by maintenance doses. I know some people might be slightly uncomfortable with the idea of the rectal administration of medicines but there are some common-sense reasons behind this form of medicines delivery particularly where oral dosage forms (tablets, capsules) might not be well tolerated. As for the initial oral dosage form: "the participants began either oral administration of SHGM [Standardized Human Gut Microbiota] (2.5 × 1012 cells/day) mixed in a chocolate milk, milk substitute, or juice for 2 days (divided into three daily doses)." I have to say that whilst I initially envisaged Austin Powers and his 'tastes a bit nutty' scene, this was very much NOT how things actually were.
Alongside the donor stool formulation being trialled predominantly with regards to safety and initial efficacy, researchers also surveyed participants in relation to (i) effects on their gut microbiota (diversity and species present), (ii) the presentation of bowel symptoms/habits and (iii) behavioural outcomes covering autism-specific issues (via the CARS) and more general adaptive behaviours (via the Vineland scales for example). I was also happy to see a section included in their paper labelled 'virome bioinformatics' hat-tipping the idea that gut bacteria are not the only passengers we carry in our deepest, darkest recesses.
Results: well something certainly seemed to happen when looking at before, during and after results of this case series trial. First and foremost adverse effects were small and limited (hyperactivity, irritability) meaning that in the short term at least, the poo transplants and pre-poo transplant protocols were tolerated quite well. This is also evident in the 0% study attrition rate (i.e. everyone who started the study stayed in the study).
So: "Substantial changes in GI and ASD symptoms were observed. GI symptoms, as assessed by the GSRS [Gastrointestinal Symptom Rating Scale], significantly improved for abdominal pain, indigestion, diarrhea, and constipation." The authors report some significant differences in scores over the course of the intervention period such that: "The average GSRS score dropped 82% from the beginning to end of the treatment and remained improved (77% decrease from baseline) even 8 weeks after treatment stopped." That is a helluva placebo effect! Indeed, only 2 participants from the cohort were classified as 'non-responders' on the basis of their GSRS scores over the course of the study.
Also: "Beyond these GI improvements, ASD-related behavior also improved following MTT." The sorts of changes to CARS scores being reported were in the region of a 20% reduction in 'core ASD' symptoms at 8 weeks compared to baseline reports. Further, 8 weeks after the intervention had been completed the behavioural gains ("relative to baseline") were still evident based on CARS scoring. These ratings also did not depend on whether the poo transplant was administered orally or rectally.
The authors also discuss some not unexpected changes to gut bacterial profiles in their cohort over the intervention period. At baseline: "gut bacteria were significantly less diverse in children with ASD than neurotypical controls." This finding is in line with other study results from the authors (see here). Bacterial diversity did (slowly) change over the intervention period to a point where at 18 weeks after baseline median richness "was statistically indistinguishable between the ASD and control groups." This was noted in 16 of the 18 participants with ASD.
Finally: "Specific genera that significantly changed in their relative abundances with treatment included Bifidobacterium, Prevotella, and Desulfovibrio." The authors have chosen to zoom in on Prevotella as a consequence of their results - "the increase in the relative abundance of Prevotella after MTT is consistent with their potentially beneficial role in the gut of children with ASD" - but I'd like to see a little more work done on this before any grand claims are made. As to the virome/phage side of things: "phage richness and evenness did not significantly change following MTT given the timeframe of this study" so again, there is more science needed in this area too as to hows and why (nots).
OK, I think it is worth stressing again that this was an open-label study not a gold-standard, double-blind, randomised-controlled trial or anything like that. What this means is that these results are preliminary - very preliminary - and although quite promising, need scientific follow-up for a longer period. Whilst such results are seemingly pretty good evidence for the whole 'gut-brain axis' thing with regards to autism (see here) there are still questions that need answering, not least with regards to possible mechanisms linking gut bacteria changes to behaviour changes. Do these results, for example, point to some role for intestinal permeability changes given what is already being said about 'leaky gut' in the context of [some] autism (see here) and the growing interest in a relationship between gut bacteria and gut barrier integrity? How do gut bacteria 'communicate' with the grey-pink matter floating in the skull? Questions aplenty there be. There is also a certain degree of 'yuck factor; to contend with as a result of the use of a poo transplant in this context and what this might mean for future trials and possible 'rolling out' of such an intervention assuming effectiveness is confirmed. I can just see the headlines now...
But I don't want to take anything away from these novel findings and [with caveats] the significance of the results. When one considers how many people on the autism spectrum are suffering (yes, suffering) with bowel complaints, whether functional or something rather more pathological (see here), efforts to reduce pain and any additional burden they bring should be welcomed from wherever they emerge...
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[1] Kang D-W. et al. Microbiota Transfer Therapy alters gut ecosystem and improves gastrointestinal and autism symptoms: an open-label study. Microbiome. 2017; 5: 10.
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Kang, D., Adams, J., Gregory, A., Borody, T., Chittick, L., Fasano, A., Khoruts, A., Geis, E., Maldonado, J., McDonough-Means, S., Pollard, E., Roux, S., Sadowsky, M., Lipson, K., Sullivan, M., Caporaso, J., & Krajmalnik-Brown, R. (2017). Microbiota Transfer Therapy alters gut ecosystem and improves gastrointestinal and autism symptoms: an open-label study Microbiome, 5 (1) DOI: 10.1186/s40168-016-0225-7
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