Inflammatory bowel disease (IBD) is an umbrella term for a family of closely related diseases (e.g. Crohn’s disease and Ulcerative colitis) that involve chronic inflammation, driven partly by the body’s own immune system, in the guts and/or digestive tract. Over the past 20 years, IBD has become a public health challenge with more than 6 million people diagnosed with the disease as of 2017 and increasing incidence every year.
The current gold standard techniques for diagnosing and monitoring gut inflammation for IBD patients are colonoscopies and biopsy analysis. These are very precise ways to monitor disease; however, the techniques are invasive and uncomfortable for patients, and puts a strain on health services with large numbers of patients on waiting lists for the procedures. Meanwhile, clinical samples such as stool or blood from patients can provide relevant information, quickly and cheaply with minimal patient discomfort, regarding the presence of proteins produced by the body in response to IBD (e.g. faecal calprotectin or blood C-reactive protein). However, these biomarkers are only generic indicators of inflammation and lack detailed information on the state of the immune system inside your gut.
Our project IBDIMAGE aimed to address the need of developing a better readout of the activity of the immune system in the gut by utilising a chemical imaging agent that can release a fluorescent signal upon the detection of a protein known as granzyme B. Prior to the beginning of the project, we optimized the development of a fluorescent chemical, known as Granzyme B Green (GzmB Green), which features fast reactivity, specificity and release of fluorescent light upon interaction with granzyme B protein. This protein is released by immune cells when they begin attacking the body and has been shown to be important in IBD, therefore we hypothesized that the detection of granzyme B protein activity in a clinical sample would be able to provide better diagnosis and monitoring than existing techniques. Alongside the development of the scientific technology, we also aimed to involve patients in discussions to turn the idea into a product that can be used to benefit patients and healthcare systems.
Our first objective of the project was the scale up and quality assessment of our chemical imaging agent GzmB Green. We were able to successfully synthesize large quantities of this chemical and we demonstrated that it selectively reacted with granzyme B over other closely related proteins. We also performed a shelf life and formulation analysis, which revealed the imaging agent is stable in the fridge and freezer as a liquid for at least 1 month.
Next, we released a patient survey in collaboration with Crohn’s & Colitis UK which received over 100 responses. The questionnaire revealed that IBD patients agreed new tests for disease diagnosis and monitoring are required and the majority favoured giving clinical specimens, in the forms of blood or stool samples. Our survey also informed us that approximately 65% of patients would like to provide their samples at home and also many were keen to use at home tests. This survey was extremely useful in shaping our research as it encouraged us to consider a plan for a future at-home test for granzyme B activity.
Through our clinical collaborations we were able to access approximately 100 stool samples from patients classified as IBD or non-IBD based on their faecal calprotectin scores. After stool sample processing and optimization, we were able to develop an assay that can differentiate stool supernatants from IBD patients vs non-IBD patients. The team is now validating these results in larger cohorts and analysing how this information could be useful in a clinical context for patient diagnosis and monitoring. The team has also recently received funding from Scottish Enterprise to build a business case with the results stemming from this project that could potentially lead to spin-out formation.
