Study finds cells linking chronic psychological stress to inflammatory bowel disease

Pennsylvania [US], June 11 : According to a study from the University of Pennsylvania's Perelman School of Medicine, cells that are connected to the relationship between stress reactions in the brain and inflammation in the gastrointestinal (GI) tract have been found for the first time in animal models.

The results of the study were reported in Cell. The enteric nervous system (ENS), a semi-autonomous neuronal system within the GI tract, receives stress signals from the central nervous system (CNS) via glial cells, which support neurons. These psychological stress signals may encourage inflammation and exacerbate the signs and symptoms of inflammatory bowel disease (IBD).

IBD, also known as Crohn's disease and ulcerative colitis, affects an estimated 1.6 million people in the United States today. Both conditions are distinguished by inflammation of the GI tract and can cause symptoms such as recurring diarrhoea, stomach pain, and bloody stools. The gastrointestinal system may suffer irreparable harm from protracted inflammation. As treatments, anti-inflammatory drugs, immune suppressants, dietary changes, and steroids are now employed.

"Clinicians have long observed that chronic stress can worsen IBD symptoms, but until now, no biological connection has been identified to explain how the digestive system knows when someone is stressed," said senior author Christoph Thaiss, PhD, an assistant professor of Microbiology.

Researchers discovered that mice with IBD exhibited severe symptoms when stressed, just as humans. They followed the first stress response signals to the adrenal cortex, which releases glucocorticoidssteroid chemicals that trigger the body's physiological reactions to stress. The researchers discovered that neurons and glia in the ENS responded to chronically high glucocorticoid levels, indicating that they constitute the connection between brain stress perception and intestine inflammation.

While glucocorticoids typically have an anti-inflammatory effect in the body, the researchers found that when glia in the ENS were exposed to the steroid hormones for a prolonged period, such as during chronic stress, they attract white blood cells to the GI tract that increase inflammation. The researchers also found that when exposed to chronic stress, the neurons in the ENS in the GI tract stop functioning as they normally do, which can lead to impaired bowel movements and exacerbated IBD symptoms.

Thaiss and collaborators verified the connection between psychological stress and IBD symptoms in humans using the UK Biobank and a patient cohort from the IBD Immunology Initiative at Penn Medicine. They found that in patients with an IBD diagnosis, the level of reported stress correlated with an increased severity of IBD symptoms.

"This finding highlights the importance of psychological evaluations in patients being treated for IBD, as well as to inform treatment protocols," said Maayan Levy, PhD, an assistant professor of Microbiology and co-senior author of the study, adding, "One of the most common treatments for IBD flare-ups is steroids, and our research indicates that in patients with IBD who experience chronic stress, the efficiency of this treatment could be impaired."