Circulating markers of gut barrier function associated with disease severity in primary sclerosing cholangitis

Background & Aims One important hypothesis in primary sclerosing cholangitis pathophysiology suggests that bacterial products from an inflamed leaky gut lead to biliary inflammation. We aimed to investigate whether circulating markers of bacterial translocation were associated with survival in a Norwegian primary sclerosing cholangitis cohort. Methods Serum levels of zonulin, intestinal fatty acid binding protein, soluble CD14, lipopolysaccharide and lipopolysaccharide-binding protein were measured in 166 primary sclerosing cholangitis patients and 100 healthy controls. Results Lipopolysaccharide-binding protein and soluble CD14 were elevated in primary sclerosing cholangitis compared with healthy controls (median 13 662 vs 12 339 ng/mL, P = 0.010 and 1657 vs 1196 ng/mL, P < 0.001, respectively). High soluble CD14 and lipopolysaccharide-binding protein (values >optimal cut-off using receiver operating characteristics) were associated with reduced liver transplantation-free survival (P P = 0.005, respectively). The concentration of soluble CD14 was higher in patients with hepatobiliary cancer compared to other primary sclerosing cholangitis patients and healthy controls. Zonulin was lower in primary sclerosing cholangitis than controls, but when excluding primary sclerosing cholangitis patients with increased prothrombin time zonulin concentrations were similar in primary sclerosing cholangitis and healthy controls. Concomitant inflammatory bowel disease did not influence the results, while inflammatory bowel disease patients without primary sclerosing cholangitis (n = 40) had lower concentration of soluble CD14. In multivariable Cox regression, high soluble CD14 and high lipopolysaccharide-binding protein were associated with transplantation-free survival, independent from Mayo risk score (HR: 2.26 [95% CI: 1.15-4.43], P = 0.018 and HR: 2.00 [95% CI: 1.17-3.43], P = 0.011, respectively). Conclusions Primary sclerosing cholangitis patients show increased levels of circulating markers of bacterial translocation. High levels are associated with poor prognosis measured by transplantation-free survival, indicating that ongoing gut leakage could have clinical impact in primary sclerosing cholangitis.