“We are not fully human,” announced Dr. Shaiya Robinson, a research fellow at SickKids, last Saturday at the Go With Your Gut conference. “In fact, recent estimates place the ratio of bacterial cells and mammalian cells at something like one-to-one, which literally means you are just as much bacteria as you are human.”
Go With Your Gut, a conference hosted by the Laboratory Medicine and Pathobiology Student Union on January 11, explored the impact of gut microbiota on health and disease.
The forum took place in the MacLeod Auditorium and featured talks by U of T researchers including Dr. Dana Philpott, Dr. Alberto Martin, and Dr. Susan Poutanen, who spoke on recent developments in understanding how intestinal microbes contribute to inflammatory bowel disease, colon cancer, obesity, and more.
The impact of gut microbiota on Crohn’s disease
The talk began with insights from Philpott, a professor at the Department of Immunology whose lab uses mouse models to study the interplay between genetics and bacteria in Crohn’s disease.
Philpott explained that the microbiota — the population of microorganisms living in the gut — of healthy individuals differs from that of patients with inflammatory bowel disease, and researchers can model the difference by treating newborn mice with antibiotics.
Her lab has explored whether a “short-term antibiotic regimen in the animal within the neonatal period” could have an impact on the animal’s gut microbiota. “There’s pretty good evidence now, in human studies, that repeated early-life exposure to antibiotics can increase the risk of Crohn’s disease development,” she noted.
Indeed, a recent study from her lab has shown that antibiotic treatment disturbs the intestinal bacteria of genetically susceptible mice, which makes them more vulnerable to inflammation.
The link between diet and gut microbiota
Martin, also a professor at the Department of Immunology, spoke about the interaction of genetic and environmental factors, particularly those of a person’s diet.
“There [are] two particular diets that have been linked to colon cancer, and one is the Western-style diet… and the other is a low-carb low-fibre diet,” he said.
He remarked on their work with a particular strain of E. coli that has been found to cause cancer in genetically susceptible mice, “So we want to ask whether that microbe interacts with these two different diets.”
He concluded that the “E. coli NC101 [strain] interacts specifically with a low-carb diet to enhance [tumour development].”
An audience member posed the question: “After all this research, what do you eat?” to which he answered, “I don’t want to really delve too far into this because [all this work is in] animal models, but I actually strongly think that it is probably applicable to the human condition.”
“A low-fibre diet is probably not very good… but really, this study is just beginning.”
Exploring fecal microbiota transplantation
Pivoting from causes of disease to treatment, Poutanen, a medical microbiologist, infectious diseases physician, and an associate professor at U of T, talked about fecal microbiota transplantation (FMT). FMT is the process of transporting gut bacteria from the stool of healthy donors into patients in order to recolonize their colons with healthy bacteria.
She discussed the positive results of this treatment — FMT is now recommended for treating recurrent C. difficile infection — but also the strange logistics of providing it.
“In terms of our donors, the big question at first is, ‘How do you collect the stool?’” she noted. She explained that they usually prefer to ask their donors to collect their sample in a provided container and place it in the fridge.
“And you may think that’s not very palatable — to put your stool in the fridge beside your food, but we have a very nice pack… [that looks like] an ice cream tub or a margarine tub.”
The promise of probiotics
Robinson closed the conference by discussing another emerging treatment: probiotics. She studies their utility in mouse models for preventing necrotizing enterocolitis, a serious gastrointestinal disorder which threatens the lives of preterm and low-birth-weight babies.
She also gave advice to young researchers, saying: “Always consider why you’re doing your research. Who does your research help, and how will it help them?” She further encouraged them to think “about [not only] how your study will drive the research field forward, but also how it drives society forward.”
Those not interested in performing research themselves can contribute by donating stool to the FMT trials, through projects such as the Microbiota Therapeutics Outcomes Program.
As Poutanen’s recruitment poster said: “Instead of flushing it down the drain, you could help someone in pain!”