P410. Microbiota profiling in PSC and control patients: A pilot study
N. Rossen1, S. Fuentes2, K. Boonstra1, G. D'Haens1, H. Heilig2, E. Zoetendal2, W. de Vos2, C. Ponsioen1, 1Academic Medical Center, Gastroenterology & Hepatology, Amsterdam, Netherlands, 2Wageningen University, Laboratory of Microbiology, Wageningen, Netherlands
Primary sclerosing cholangitis (PSC) is a cholestatic liver disease, strongly associated with a particular phenotype of inflammatory bowel disease (IBD) with right-sided colonic involvement. The aim of our study was to characterize the intestinal mucosal microbiota at the ileocecal level in PSC patients.
We included PSC patients, UC patients and non-inflammatory controls. The microbiota composition based the on 16S rRNA diversity was determined on pooled ileal-cecal biopsies per patient using the Human Intestinal Tract Chip (HITChip) (Rajilic-Stojanovic et al, Environ. Microbiol. 2009).
We prospectively included 34 patients; 14 patients in the PSC group, 11 patients in the UC group and 9 non-inflammatory controls. In the PSC group, median age was 37.5 years (IQR 25–55), 86% of the patients were male, median PSC disease duration was 4.5 years (range 0–17) and 12 of these PSC patients (86%) had concomitant IBD; 4 Crohn's disease (CD) and 8 ulcerative colitis (UC). In the UC group, median age was 50 years (IQR 37–67) and 82% of the patients were male. In non-inflammatory controls, median age was 65 years (IQR 50–70) and 78% were male. Samples did not cluster by disease group. Similarity of the profiles within the PSC cohort was different compared to non-inflammatory controls (p = 0.03). At genus-like level, the relative abundance of Uncultered Clostridiales was lower in PSC (0.24±0.10%) compared to IBD (0.41±0.29%) and controls (0.49±0.25%) (False discovery rate: 0.038; p ≤ 0.001). No significant differences in diversity and evenness were found, but the richness differed across the groups and was lowest in the PSC patients: 685±181 in PSC, 746±210 in IBD and 821±175 in controls (p = 0.02).
The mucosal adherent microbiota at the ileocecal level in PSC patients shows significantly reduced richness. At genus-like level, the relative abundance of Uncultured Clostridiales is significantly lower as compared to IBD- and healthy controls. The reduced amounts of the Uncultured Clostridiales in PSC biopsies can be considered as an indication for a compromised gut as we have recently observed that this group of not yet cultured Firmicutes correlates significantly with health (Lahti et al, unpublished data).