We have known for some time that there is a strong connection between the intestine and the brain, so much so that over the past twenty years, various researches have discovered links between autoimmune disorders and different psychiatric conditions. The strong suspicion is that the intestinal microbiome, that is the set of all bacteria that live in the various tracts of our intestine, strongly influences brain health but this relationship is fundamentally unknown.
Now a new study, conducted by scientists at Weill Cornell Medical College, provides new insights into the molecular cellular processes that underlie communication between the same microbes in the gut and brain cells. As David Artis, director of the Jill Roberts Institute for Research in Inflammatory Bowel Disease and professor of immunology, explains, this research represents a sort of initial path to understanding “the whole picture” about the chronic gastrointestinal conditions that affect mental health and even the behavior.
The researchers used experiments on mice to understand the changes that occur in brain cells when the gut microbiome begins to run out. In fact, the researchers reduced the microbial populations in the intestines of mice through antibiotics. These mice showed very limited learning abilities, for example in learning that a danger or threat was no longer present. By analyzing the microglia of the brain of mice, the researchers discovered an altered gene expression in these cells that influenced the connection between brain cells during the learning processes.
Furthermore, in mice with a smaller quantity of bacteria in the intestine, changes in the concentrations of different metabolites linked to various neuropsychiatric disorders that also occur in humans, such as schizophrenia or autism, could be noted.
“Brain chemistry essentially determines how we feel and respond to our environment, and evidence is showing that chemicals derived from gut microbes play an important role,” says Frank Schroeder, professor at the Boyce Thompson Institute and one of the authors of the study.
This study confirms the existence of a strong link between the intestine and the brain and how this same connection affects our day-to-day life and only now is it starting to understand how the intestine itself, or rather the bacteria inside it, can even affect diseases such as autism, Parkinson’s and depression.
Maybe in the future, we will be able to identify new objectives for the treatment of these diseases, as suggested by Conor Liston, associate professor of neuroscience in the Feil Family Brain & Mind Research Institute and the other author of the study.