Fecal transplants reduce ADHD and anxiety symptoms in dogs with epilepsy, researchers find

Researchers from the Texas A&M College of Veterinary Medicine and Biomedical Sciences (VMBS) and Center for Systems Neuroscience in Hannover, Germany have discovered that fecal microbiota transplants (FMT) can reduce negative mental health symptoms in dogs with epilepsy—especially in dogs with a version of epilepsy that is resistant to drugs.

The work is published in the journal Frontiers in Veterinary Science.

FMT is a non-invasive treatment delivered via enema that has become popular in human medicine over the last two decades thanks to increased scientific understanding of the gut microbiome—the community of bacteria living in the gut that helps regulate healthy digestion.

Scientists have also discovered evidence that the gut microbiome may play an even bigger role, influencing other parts of the body—including the brain in what is called the gut-brain axis. Veterinary science experts have also begun studying this relationship with regards to animal health.

In their recent study, the researchers treated nine dogs with drug-resistant epilepsy—a type of epilepsy that does not respond to the usual drug therapies and affects approximately two-thirds of dogs with epilepsy. According to the study, dogs with this version of the disease tend to experience more ADHD- and anxiety-type symptoms than other dogs with epilepsy.

“Each patient in the study received FMT three times over a period of several weeks, and was monitored during follow-up appointments,” said Dr. Jan Suchodolski, the associate director of research and head of microbiome sciences at the Texas A&M Gastrointestinal Laboratory. “After treatment, each of the nine dogs showed significant improvements to their mental health, including a reduction of anxiety-like behavior and improved quality of life.

“While we don’t yet understand the mechanism causing these behavioral improvements, we hope to continue developing new ways to help patients with drug-resistant diseases using microbiome science,” he said. “Research in this field is highly translational, meaning it is helpful to both human and veterinary medicine.”

The gut and the brain

It may seem counterintuitive to try treating mental health symptoms using gut health, but all the evidence points toward a mysterious connection between these two bodily symptoms.

“The gut has a far more central role in overall health than most people realize,” Suchodolski said. “We talk about the gut-brain axis, but there is also the gut-kidney axis, the gut-liver axis, and others.”

The relationship between the gut and other body systems isn’t well understood yet, but scientists are steadily gathering more information.

“We know that situations with high levels of mental stress can affect gut motility,” Suchodolski said. “There are also several neurological diseases—including Alzheimer’s disease and strokes—that also seem to cause gut symptoms in patients, and vice versa. There have also been studies showing that changing the gut’s microbiome with probiotics or diet alterations can also affect disease symptoms, so there’s a lot of evidence of this relationship.”

FMT is just one kind of treatment that makes use of the gut-brain relationship, and it’s proving to be highly effective.

“If you think of the microbiome like a garden, FMT is like putting in a whole new ecosystem,” Suchodolski said. “You’re adding in all kinds of bacteria and other organisms to see if something changes.

“What’s most interesting is that our research team measured the seizure frequency in the patients after the treatment, and that improvement was not very strong. The behavior change was much more pronounced,” he said.