The human intestine is composed of various cell types. Enteroendocrine cells are specialized cells located in the gastrointestinal tract, they produce and release hormones into the bloodstream. These hormones control many important processes, but their role in inflammatory bowel diseases is not yet fully understood.
The intestinal hormone GLP-1 influences digestion and inflammation
The enteroendocrine cells secrete many different hormones. These ensure that nutrients can be properly absorbed by the body. The best known of these hormones is GLP-1, where GLP stands for “glucagon-like peptide.” Many connections are already known: GLP-1 regulates satiety, insulin levels, and gastrointestinal transit.
Medications that mimic the effects of GLP-1 are used to treat diabetes and obesity, for example as so-called weight loss injections. What is less well known is that GLP-1 also appears to coordinate metabolic inflammatory responses and may influence inflammatory processes in the intestine.
In patients with chronic inflammatory bowel disease, it was unclear whether their intestinal hormones were also altered. Measurements in blood samples provided conflicting data on the various hormones.
Changes in the epithelial cells of the intestine
Dr. Eva Rath's team used biopsies to examine the intestine itself – specifically its epithelial cells, which form the intestinal barrier. This cellular layer also contains enteroendocrine cells. The results were clear: mice with intestinal inflammation and humans with Crohn's disease had fewer cells that produced GLP-1. In addition, transcription analyses showed that this decline begins even before the inflammation becomes noticeable.
Epithelial cells regenerate continuously, but they do not fully mature in the presence of inflammation, or to put it scientifically: they are not terminally differentiated. This in turn affects inflammatory conditions and the associated symptoms in many ways.
Not only GLP-1, but also other intestinal hormones are affected. This could be considered in future therapies.
More information about the research
Dr. Eva Rath, last author of the study, recently completed her postdoctoral qualification at TUM. She is researcher at Prof. Dirk Haller's Chair of Nutrition and Immunology.
The original publication: Reduced Intestinal GLP-1+ Cell Numbers Are Associated With an Inflammation-related Epithelial Metabolic Signature. Cellular and Molecular Gastroenterology and Hepatology, Volume 20, Issue 2, 2026 (open acess). doi.org/10.1016/j.jcmgh.2025.101656
TUM-News (2020): Early detection of Crohn’s disease flare-ups leads to improved therapy options –Preserving inflammation-free phases (study on the alteration of stem cells at the Chair of Nutrition and Immunology)