Researchers have identified a specific enzyme as a useful indicator of gut inflammation and developed an optical reporter that can show this enzyme’s activity. This quick, non-invasive and IBD-specific reporting tool could be used to enhance the diagnosis and monitoring of IBD patients over existing tests. Inflammatory Bowel Diseases (IBD), including ulcerative colitis and Crohn’s disease, are chronic conditions where the body’s immune system mistakenly attacks the digestive tract, leading to long-lasting inflammation. A key contributor in this immune response is the T cell - a type of white blood cell which usually helps protect the body by finding and fighting infections or abnormal cells. However, in IBD, T cells mistakenly see the gut as a threat and become overactive, which can lead to tissue damage. Diagnosis and monitoring of IBD often rely on expensive and invasive procedures like colonoscopies. This is where a small camera is used to examine the gut, and is when tissue samples, or biopsies may be taken. Imaging scans such as MRI or CTs can also be used but don’t provide clear images of the gut’s inner lining. Less invasive methods include the measuring of inflammation markers, such as the protein calprotectin (released by white blood cells) in stool samples, but these general inflammatory markers are not specific to IBD. Chemical reporters, such as those created by the IRR Chemistry Hub, are great tools for showing how small molecules in cells are working and measuring their levels. Recently, the Vendrell lab developed chemiluminescent reporters that light up when they detect certain enzymes and substances in preclinical models. This new study is a collaboration with Professor Marc Vendrell, co-Head of the IRR Chemistry Hub and Professor Gwo-tzer Ho, IRR Honorary Consultant Gastroenterologist who has recently moved to the University of Glasgow. The notable speed and sensitivity of our activity-based chemiluminescent tools hold potential to accelerate future studies of immune-mediated regulation in IBD. These optical tools could also be used to help develop personalised medicine. Professor Marc Vendrell IRR Group Leader and paper’s corresponding author Granzyme A activity is an indicator of gut inflammationIn this study, researchers analysed gut tissue biopsies from IBD patients. Researchers found high levels of a specific enzyme called granzyme A (GzmA) in inflamed tissues compared to non-inflamed tissues. These enzymes cause inflammation by activating further immune responses. They also found that GzmA is primarily released by a specific type of T cell (CD8+ or killer T cell). Microscopy images of colon tissue samples of IBD patients under remission (left) and with active disease (right). Granzyme A (green fluorescence) is elevated in the intestinal tract of IBD patients (right). Credit: Emily Thompson. Optical reporter measures Granzyme A activity in biosamples from IBD patientsResearchers then designed the first non-invasive fluorescent reporter tool to measure GzmA activity in stool samples from IBD and healthy patients. Combining the researchers’ new reporting tool to analyse GzmA activity with the current common testing of faecal calprotectin levels had a more successful identification of IBD in patients when compared to using faecal calprotectin scores alone. This new study highlights a fast, non-invasive and IBD-specific reporting tool could be used to enhance the diagnosis and monitoring of IBD patients over existing tests. These optical tools could also be used to help develop personalised medicine in the future.This work was supported by the European Research Council, the Medical Research Council, Marie Sklodowska-Curie Awards and Leona M. and Harry B. Helmsley Charitable Trust.Related linksRead the full paper in Nature Biomedical Engineering Marc Vendrell research groupIRR Chemistry HubHo research group Tags CIR Publication date 13 Jan, 2026
