Stress not only affects the mind but can also impact physical health, with a new study in mice suggesting that gut bacteria might be to blame. Published on August 8 in *Cell*, the research reveals that a stressed brain can shut down certain glands in the gut, disrupting gut bacteria and affecting the body’s immune system.
John Cryan, a neuroscientist at University College Cork in Ireland, praises the study for its innovative approach. While most research on the gut-brain connection has focused on how bacteria influence the brain, this study explores how psychological stress can exert a top-down influence on gut bacteria, adding a new layer to our understanding of the mind-body relationship.
The researchers, led by Ivan de Araujo from the Max Planck Institute for Biological Cybernetics in Germany, focused on small glands in the small intestine known as Brunner’s glands. They found that removing these glands in mice made the animals more susceptible to infections and increased signs of inflammation. Further analysis revealed that the removal of these glands also eliminated bacteria from the *Lactobacillus* genus, which are crucial for maintaining the gut barrier. Without these bacteria, the gut becomes “leaky,” allowing unwanted molecules to enter the bloodstream, triggering an immune response that leads to inflammation and illness.
The study also uncovered that neurons in Brunner’s glands are connected to the vagus nerve, a key communication pathway between the gut and the brain. When the mice were subjected to chronic stress, their *Lactobacillus* levels dropped, and inflammation increased, suggesting that stress can deactivate these glands and disrupt the microbial balance.
This discovery highlights a direct connection between the brain, Brunner’s glands, gut bacteria, and the immune system. While results in mice may not directly translate to humans, the study opens new avenues for exploring how stress affects the body and could have implications for treating stress-related disorders, such as inflammatory bowel disease. De Araujo’s team plans to investigate how chronic stress might affect this pathway in infants, proposing that these glands are vital for normal development and immune function from an early age.
Reference: Hao Chang, Matthew H. Perkins, Leonardo S. Novaes, Feng Qian, Tong Zhang, Peter H. Neckel, Simon Scherer, Ruth E. Ley, Wenfei Han, Ivan E. de Araujo (August 08, 2024). Stress-sensitive neural circuits change the gut microbiome via duodenal glands. https://www.cell.com/cell/fulltext/S0092-8674(24)00779-7?_returnURL=https%3A%2F%2Flinkinghub.elsevier.com%2Fretrieve%2Fpii%2FS0092867424007797%3Fshowall%3Dtrue#articleInformation
