In recent years, researchers have found they that by transferring the gut microbiome from animal to animal, they can also transfer particular “disease” states. Take obesity, for instance – just one example of many – researchers transferred the gut microbiota from lean mice fed a healthy diet to obese ones fed a high fat diet, and showed that the benefits of the healthy diet, in terms of metabolic rate and so forth, could be conferred on the unhealthy rodents: “Our findings demonstrate that the beneficial effects of diet and exercise are transmissible via FMT [fecal microbiota transplant], suggesting a potential therapeutic treatment for obesity.”[i]
Just a few weeks ago, in fact, I wrote about the semi-successful first attempt to use FMT to treat obese people. (It was semi-successful in that, the treated individuals did not lose weight. However, their gut microbiota did end up resembling that of thin people. The study was just a first step and certainly opened up the door to more research going forward.)
For several years now, research has also shown that it is possible to transfer depression via microbiota transplant. For example, in 2016 a paper was published wherein scientists took the microbiota from depressed humans, and transferred it into rats, inducing, “…behavioral and physiological features characteristic of depression in the recipient animals…”[ii]
Then came Jim Adams and colleagues, at Arizona State University, who used fecal transplant in an open-label study in autism, and found that they could confer an 80% reduction in GI symptoms and also radical improvement in the symptoms of autism in the children: “…clinical assessments showed that behavioral ASD symptoms improved significantly and remained improved 8 weeks after treatment ended.”[iii] It was huge news, a couple of months ago, when the follow up study was published by these same scientists, which showed that the gains these children had made were retained 2 years later: “…most improvements in GI symptoms were maintained, and autism-related symptoms improved even more after the end of treatment.”[iv] (This of course makes perfect sense. GI symptoms were mostly maintained but of course, would be diet dependent. And autism symptoms like speech issues require months of therapy to show improvement. If the microbiota transplant worked, you’d expect the children to be able to learn better and more efficiently, and improve continually over time.)
Having read these, and many other such studies over the years, the latest big biome news in the autism world came as absolutely no surprise to me. Last week, researchers at the California Institute of Technology reported that the symptoms of autism can be transferred to mice via FMT.[v] They took germ-free mice, infused them with the gut bacteria from children on the autism spectrum, and low and behold: “…these mice were less vocal than the mice in the control group. They also tended to engage in more repetitive behaviors and spent less time interacting with other mice.”[vi] They also found differences in the brains of the treated mice, including changes in certain molecules (metabolites) which were at lower levels in the “ASD” mice. These particular metabolites, taurine and 5AV (5-amonovaleric acid) affect the levels of GABA in the brain, a neurotransmitter responsible for calming neurons down after they’ve been stimulated. Many kinds of seizures, which involve abnormal neuronal excitement, for example, are associated with low levels of GABA. And abnormal levels of GABA have long been associated with autism spectrum disorders.
The researchers took the research a step further and gave 5AV and taurine to a particular kind of mouse (called BTBR) which has been bred to have autism-like behaviors: “The study found that treating the mice with either 5AV or taurine led to noticeable decreases in the characteristic ASD-like behaviors…And, when the researchers examined brain activity in these mice, they found a strong link between increases in the levels of 5AV and decreased excitability in the brain.” To summarize: giving the mice gut bacteria from children with autism not only caused behavioral changes consistent with autism, but also caused chemical changes in the brain that parallel known alterations found in those on the spectrum.
Yes, I suppose in a way it is big news and headlines around the world were screaming it is a triumph. Honestly though, the research didn’t really rock my world. Since before my son was diagnosed, 23+ years ago, we’ve known that alterations in the gut biome are associated with autism, and most likely, the root cause. On this blog alone, I’ve written now 81 posts on the subject…and my blog is only 2 ½ years old! And I guess, since I’m all about “things you can do now,” clinical studies, like that of Jim Adams and colleagues that I discuss above, is far more exciting to me. In that study, the researchers used an oral solution of purified bacteria from healthy donors’ stool, that was mixed into milk or juice. The day that product becomes available, well – then you will see overwhelming excitement from me!
[i] Lai, Z-L, et. al. Fecal microbiota transplantation confers beneficial metabolic effects of diet and exercise on diet-induced obese mice. Scientific Reports. 2018; 8(15635).
[ii] Kelly, JR, et. al. Transferring the blues: depression-associated gut microbiota induces neurobehavioral canges in the rat. Journal of Psychiatric Research. 2016;82:109-118.
[iii] Kang, DW, et. al. Microbiota transfer therapy alters gut ecosystem and improves gastrointestinal and autism symptoms: an open-label study. Microbiome. 2017;5(1):10.
[iv] Kang, DW, et. al. Long-term benefit of microbiota transfer therapy on autism symptoms and gut microbiota. Scientific Reports. 2019;9(1):5821.