P421 The faecal biomarker LDN-051 is a novel tool for monitoring disease activity and therapeutic response in Inflammatory Bowel Diseases

Abstract

Abstract Background Crohn’s disease and ulcerative colitis, two forms of inflammatory bowel disease (IBD) require lifelong treatment and patient monitoring. Current predictors of relapse and therapeutic success have limitations, therefore there is high unmet need to identify novel biomarkers in IBD. Monitoring approaches for IBD are mostly invasive, time-consuming, and expensive. Therefore, a simple, rapid, and non-invasive test, with ability to differentiate IBD from other gastrointestinal conditions and to monitor disease activity, will have important clinical implications. Our previous mucosal cytokine profiling identified that Plasminogen activator inhibitor type 1 (PAI-1) is expressed in IBD patients with active disease, but not in control. Therefore, our aim was to assess the utility of PAI-1 in monitoring disease activity and therapeutic response of IBD patients in different biological samples. Methods Serum, biopsy and faecal samples were collected from 132 IBD patients and 30 controls without IBD. ELISA method was used to define the level of PAI-1 in the mucosa, serum, and faecal samples and the serum CRP levels were also determined. For the mucosal gene expression analysis qRT-PCR was used. The correlation and ROC analyses were applied to observe the relationship between the disease activity and PAI-1 level. Results The applied screening approach detected significant higher expression of PAI-1 in active IBD. We demonstrated that the serum, mucosal and faecal PAI-1 concentration was significantly elevated in IBD patients showing clinical and endoscopic activity. Additionally, in responder patients the initial PAI-1 level decreased significantly upon successful therapy, whereas it remained unchanged in non-responders. We also showed that faecal PAI-1 selectively increases in active IBD patients, but not in other organic gastrointestinal diseases. In addition, the stability analysis of faecal PAI-1 showed that the protein was detectable up to one week at room temperature and 4ºC. The serum, mucosal and faecal PAI-1 level showed positive correlation to the endoscopic activity. ROC curves demonstrated that faecal PAI-1 showed a relatively high power to distinguish between active and control patients. However, the serum CRP level no reflected to the therapeutic response. Conclusion Our results suggest that serum, mucosal and faecal PAI-1 expression reflects to the disease activity in IBD, which could be used to disease monitoring and possibly therapeutic response. The correlation between the faecal PAI-1 level and the endoscopic activity promotes that it could be used as a novel non-invasive disease specific faecal biomarker in the IBD diagnosis.