P: 71 Faecal Cytokine Profiling Provides Novel Insights Into Intestinal Barrier Disruption and Bacterial Translocation in Acute Decompensation of Cirrhosis

Abstract

BACKGROUND: Intestinal dysbiosis with gut barrier impairment (GBI) and bacterial translocation (BT) are recognised as central features of acutely decompensated cirrhosis (AD) and propagating hepatic encephalopathy (HE). Gut mucosal function is technically challenging to investigate, with a difficulty in obtaining representative tissue in cirrhotics and a paucity of non-invasive techniques. A novel assay we developed was to quantify faecal cytokines (FC) as surrogate makers of intestinal inflammation, compared to GBI markers and systemic cytokines. METHODS: Protein was extracted from faeces of patients with stable cirrhosis (SC; n = 16), AD (n = 48), and healthy participants (HC; n = 31). A multiplex panel of 13 cytokines were quantified by electrochemiluminescence or ELISA in paired faecal lysates and plasma. Intestinal epithelium-associated fatty acid binding protein 2 (FABP2) and intestinal-microbiota metabolite D-lactate, as markers of intestinal barrier disruption, were quantified by ELISA and colorimetric enzymatic assay, respectively. RESULTS: Median ages and MELD scores of AD vs SC patients were 61 (53–68) vs 55 (44–59) years and 18 (13–26) vs 8 (7.0–8.5), respectively. Male gender predominated (AD: 65%; SC: 75%) The causes of cirrhosis were alcohol, NAFLD and treated hepatitis C. Median venous ammonia levels were significantly higher in AD vs SC (51 [38–74] vs 36 [26–59], P = 0.027). Faecal IL-1β, IFN-γ, TNF-α, IL-21, IL-17A/F and IL-22 were significantly different in AD vs SC on univariate comparison (q < 0.01 all comparisons). Along with IL-1β, faecal IL-23 was significantly elevated in AD vs HC (P = 0.0007), important in promoting deleterious Th17 cell effector function. Faecal FABP2 and D-lactate (P < 0.0001 for both) and plasma FABP2 and D-lactate (P = 0.0004; P = 0.011) were significantly elevated in AD vs SC and AD vs HC, respectively, consistent with GBI. FABP2 was the faecal marker that correlated most strongly with disease scores (Spearman's rho: Child-Pugh 0.466, P < 0.0001; MELD 0.488, P < 0.0001). With the exception of IL-8, IL-12 & IL-23, faecal cytokines and D-lactate were more discriminant than circulating equivalent molecules in discriminating AD from SC by Principal Component Analysis (Figure 1). CONCLUSIONS: FC profiling represents a novel targeted approach to localised measurement of the intestinal cytokine milieu in cirrhosis, and in conjunction with D-lactate, demonstrates that progression to AD from SC may be a intestinally initiated and mediated process. The AD gut micro-environment may skew T cell priming away from restorative Tregs and towards inflammatory Th1/Th17 profiles, promoting epithelial barrier damage and preventing repair. These data provide insights into intestinal mucosal injury and GBI, as a novel pathobiology in AD and HE.