New Optical Assay Could Improve IBD Diagnosis and Monitoring

A new optical test that detects signs of inflammatory bowel disease (IBD) through stool samples may improve how the condition is diagnosed and monitored, according to a recent study in which University of Edinburgh scientists describe the chemiluminescence assay they created to measure the activity of a molecule linked to gut inflammation. 

IBD is a chronic disorder in which the immune system mistakenly attacks the digestive tract, leading to persistent inflammation. Diagnosis often depends on colonoscopy, an invasive procedure that uses a camera to examine the gut. Current stool-based tests, such as those measuring the protein calprotectin, can signal inflammation but cannot determine its precise source, prompting further testing.

The Edinburgh team analyzed gut tissue from IBD patients and found high levels of an enzyme called granzyme A (GzmA) in inflamed regions of the gut. GzmA, typically produced by T cells to fight infections, becomes overactive in IBD, contributing to tissue damage and inflammation. To track this activity, the team developed a luminescent tool capable of detecting GzmA directly in stool samples.

The new reporter was tested on samples from 150 individuals with and without IBD. Results showed that combining the GzmA reporter with standard calprotectin testing improved the ability to identify IBD compared with calprotectin alone. Researchers believe this could make IBD testing more accurate while minimizing the need for colonoscopies.

While the findings represent an advance in pinpointing gut-specific inflammation, the authors emphasize that more research is required before the test becomes clinically available.

According to Professor Marc Vendrell, lead author of the study published in Nature Biomedical Engineering, “The speed and sensitivity of our optical tool has the potential to accelerate future studies into the roles of the immune system in IBD, as well as improving the pathway to diagnosis. In the future, these optical tools could also be used to help tailor treatments for IBD patients.”