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P107 Monitoring inflammatory bowel disease in clinical practice using gut microbial markers in faecal samples. Prospective study in a clinical cohort.

Miquel Cusachs, J.O.(1);Bahí Saavedra, A.(2);Vila Currius, M.(3);Lliròs Dupre, M.(2);Leal Validivieso, C.(4);Aldeguer Manté, X.(1);

(1)University Hospital de Girona Doctor Josep Trueta, Department of Gastroenterology, Girona, Spain;(2)Institut d'Investigació Biomèdia de Girona IdIBGi, Reserach Group on digestive disease and microbiome, Girona- Salt, Spain;(3)University Hospital de Girona Doctor Josep Trueta, Department of Pharmacology, Girona, Spain;(4)Consorci Hospitalari de Vic, Gastroenterology Department, Vic, Spain IdIBGi

Background

The gut microbiota(GM) plays a pivotal role in the pathogenesis of inflammatory bowel disease (IBD) which includes Crohn's disease (CD) and ulcerative colitis(UC). The degree of IBD activity, and therefore of inflammation, modifies GM composition towards an altered pattern called dysbiosis This IBD-dysbiosis pattern is different from healthy individuals(HI). The degree of dysbiosis is a good indicator of IBD activity and could be useful in monitoring IBD. The AIM of this study is to quantify the degree of IBD dysbiosis of the GM, and determine the utility as a biomarker for monitoring IBD disease compared with HI.

Methods

80 IBD patients from 2 tertiary hospitals have been included. We included patients with clinical Remission (R), defined as Faecal Calprotectin (FC) levels <250 µg/gr., and Activity (A) (FC >250 µg/gr.) with mild to moderate disease. A blood sample (to determinate RCP, albumin and hemoglobin (Hb) levels) and stool sample (to determinate Faecal calprotectin (FC) and GM analysis) has been collected. DNA was extracted from fecal samples, using real-time qPCR techniques and 3 bacterial groups (Faecalibacterium prausnitzii (FP), Escherichia coli (EC), and total eubacteria (TE) that are highly representative of GM dysbiosis degree were analyzed. In regards to these bacteria, an index called FEI has been created to quantify GM dysbiosis. GM and FEI data has been collected in order to compare with standards analytical markers (Hb, Alb, RCP, FC). The duration of this study is 6 months with samples every three months (T0, T1 and T2).

Results

35 UC and 45 CD patients were included. Initial treatment in 76,25% of cases were biological drugs. 55 % of patients were in remission at first sample. The analysis of clinical data showed that only PCR and CP had significantly differences between R and A (p=0,0037) and type of disease (p=0,018) and temporal evolution (p=0,004). Higher levels of FP are been observed in UC (p=0,0013) and higher levels of EC in CD (p=0,003) in all 3 samples. FEI values are higher in UC (p=0,001) and different between CD and UC and HI (p=0,015) indicating FEI ability to differentiate between 2 disease subtypes and HI. FEI cut-off point has been set at 1,869 (S 0,44 and E0,82; AUC 0,658) in T0. The IBD-GM compared with HI-GM showed lower FP abundance (p=0,002) and higher TE abundance (p=0,0001) with increased non-significant EC abundance. The A and R abundances for FP,FEI and TE showed significant differences between CD, UC and HI, indicating capacity to differentiate between activity and remission in T0.

Conclusion

Microbiological markers and FEI allow to differentiate between IBD subtypes and HI, and between A and R. The combination if RCP, FC and FEI can become a potential biomarker of IBD activity.

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