Fecal microbiota transplant (or FMT, in short), already approved in several countries to treat the infection caused by the Clostridium difficile bacterium, is also achieving significant results in a very different field: autism or, to be more precise, autism spectrum disorders (ASD). The journal Scientific Reports, part of the Nature group, published the results of a study in this area conducted by the University of Arizona (USA) on 18 autistic children treated in 2017: after a microbiota transplant (i.e. after the bacteria that populated the intestine of donors in a well-balanced manner was transferred to the children), the main symptoms of autistic disorders (namely those concerning language, social relationships and behavior) were reduced by 45%, whereas gastrointestinal disorders decreased by 58%.

The idea of trying FMT originates from an observation: the most severely-autistic patients always have major imbalances of microbiota, with chronic gastrointestinal problems like diarrhea, constipation and colitis, and this aggravates their condition, also causing irritability, behavioral disorders, and difficulty in concentrating and learning. These two aspects are linked, because it is well-known that when gastrointestinal disorders are treated, the other symptoms also improve.

Within the context of the study conducted by the University of Arizona, the children were treated first with the antibiotic vancomycin to reduce the presence of pathogenic bacteria, and then with a fecal microbiota transplant every day for seven to eight weeks. The initial results, published in 2017, already gave reason for hope, because the improvement in symptoms was obvious. However, the current results, i.e. the follow-up report after two years, have proven to be particularly significant, because the percentage of children classified as severe went from 83% to 17%.

“We are discovering a very strong connection between the microbes that live in our intestine and the signals that travel towards our brain”, says Rosa Krajmalnik-Brown, professor at the Biodesign Swette Center for Environmental Biotechnology of the University of Arizona, “In many cases, when the gastrointestinal problems of autistic children are treated, their behavior improves”. FMT is based on the treatment of the feces of a donor with specific characteristics (the feces contain a very high number of intestinal bacteria). A lyophilisate is obtained, which makes the transplant possible, normally carried out via a colonoscopy. Within a very short period of time, the microbiota of the recipient changes and becomes more and more similar to that of the donor, with benefits that are being measured also in the treatment of other illnesses: for example, fecal microbiota transplant appears to have positive effects, in several carefully-selected cases, in the treatment of tumors, because it helps patients to reap greater benefits from immunotherapy, for reasons that are yet to be explained. The results of two studies in this area were described at the recent congress of the American Association for Cancer Research, as reported in the journal Science.

Going back to autism, the researchers from the University of Arizona write that it will be necessary to confirm the results in wider groups of people, but the road to a new therapeutic approach (towards an illness in which pharmacological remedies are basically non-existent) seems to be marked out.

Barbara Mazzolai