Introduction

The gut-liver axis is substantially involved in the pathogenesis of chronic inflammation of the liver. Disruption of both the mucosal immunity and the structural integrity of the gut barrier results in sustained leakage of bacterial antigens from the gut lumen (i.e., bacterial translocation, BT) to the portal circulation. Enhanced BT triggers the activation of the proinflammatory signaling cascade and consequently increases tissue damage of the liver. This latter hence accelerates the progression of the liver disease. Markers of gut barrier integrity and function were hypothesized to be associated with severity an outcome of acute decompensation (AD) episodes in patients with cirrhosis.

Aims & Methods

In various chronic gastrointestinal diseases a bundle of serologic markers were identified as a hallmark of the intestinal barrier disruption and tissue damage in general. These serologic markers were tested in a prospective cirrhotic patient cohort suffering in AD to determine their prognostic potential for worse outcome. Serum samples of 131 patients with cirrhosis and AD have been assayed for gelsolin, intestinal fatty acid binding protein (I-FABP), zonulin, secretory immunoglobulin A (sIgA), free Ig kappa and lambda light chains, immunoglobulin (Ig) A and/or IgG antibodies against to EndoCab gliadin, F-actin, Saccharomyces cerevisiae (ASCA), glycoprotein 2 (GP2), as well as total IgA, IgG and IgM levels. Disease severity was assessed by different liver related scores (CLIF-C AD, MELD and Child-Pugh). Presence of acute-on-chronic liver failure (ACLF) was defined by CLIF-OF score. Hospital readmission, ACLF development and liver-related death were assessed in a 3-month follow-up observational study.

Results

Presence of anti-microbial and other target specific IgA type antibodies was associated with diseases severity. The more types of IgA antibodies present the higher the total IgA level was. High CLIF-C AD score (≥ 50) was associated with increased gelsolin and decreased total IgG levels at baseline, while presence of ACLF at hospitalisation with increased free Ig kappa light chain (p=0.043) and decreased total IgG levels (p=0.046). Hospital readmission due to a further AD episode within 3-month was associated with increased gelsolin level at baseline episode (p=0.042), while ACLF development was associated with increased free Ig kappa light chain level (p=0.018). Short-term mortality was associated with increased gelsolin level (AUROC: 0.814 and 0.664, p<0.001 and =0.012 for 1 and 3-month mortality, respectively). The addition of high (> 68 µg/ml) serum gelsolin level significantly increased 3-month mortality prediction in all 3 severity category (CLIF-C AD <50: 0% vs. 24.3%; CLIF-C AD ≥50: 15.9% vs. 36%; ACLF: 22.2% vs. 54.5%, respectively, cumulative LogRank p<0.001).

Conclusion

Presence of specific IgA type antibodies signifying enhanced BT contributes to the increased total IgA level in advanced liver cirrhosis. Serologic hallmark of overwhelming damage-associated molecular patterns (DAMPs) in AD episode is able to predict more presicely the accelerated progression of liver disease adding to CLIF-AD score that comprises extent of certain organ dysfunctions and systemic inflammatory response.

Introduction

Chronic pancreatitis is one of the well-known risk factors of pancreatic adenocarcinoma, the 4th leading cause of cancer mortality. Excessive chronic alcohol consumption is the first cause leading to chronic pancreatic and hepatic inflammation. The intestinal microbiota plays a role in the pathogenesis of these two diseases and patients with chronic alcoholic pancreatitis (CAP) or alcoholic hepatitis (AH) display altered and specific gut dysbiosis, with a higher relative abundance of Enterococcus in patients with CAP compared to AH(1). A recent study identified strains of E. faecalis able to produce a toxin, called cytolysin, responsible for liver lesions in chronic liver diseases. Its presence was associated with the worst clinical outcomes(2). It is yet unknown whether patients with CAP also exhibit an elevated relative abundance of cytolysin-producing E. faecalis strains.

Aims & Methods

The objectives of this study were 1/ to assess the presence of E. faecalis strains expressing or not cytolysin, in the intestinal microbiota of patients with CAP (n = 24) compared to patients with AH (n = 27) and to healthy controls (HC, n = 28), 2/ to evaluate the role of E. faecalis strains (isolated from the patients), in the genesis and potentiation of pancreatitis lesions and early precancerous lesions (acinar-to-ductal metaplasia), in a murine model of pancreatitis induced by cerulein, and 3/ to assess the presence of Enterococcus in surgical specimens of patients who went under pancreatic resection for CAP, (n = 6) compared to controls (normal pancreatic parenchyma apart of benign tumors n = 4).

Results

Our data showed that the relative abundance of cytolysin-positive E. faecalis in the intestinal microbiota is elevated in patients with AH and even more in patients with CAP. Genomic DNA of E. faecalis was detected in 96% of CAP patients, and 85% of AH patients. CAP patients were more frequently cytolysin-positive (96%) than HC (39%, p < 0.001) or AH patients (48%, p < 0.001). The relative abundance of cytolysin-positive E. faecalis was elevated in CAP and AH patients (p = 0.0006 and p= 0.0067) but not HC. In our murine model of cerulein-induced chronic pancreatitis, E. faecalis tend to increase the rate of pancreatitis lesions, as well as the number of acinar-to-ductal metaplasia lesions, specifically when pancreatitis is triggered. We used two different anti-Enterococcus antibodies with concordant results, showing that Enterococcus is present in the pancreatic parenchyma of patients with CAP, but not in the healthy pancreas of controls.

Conclusion

These results support a potentially detrimental role of Enterococcus, and especially E. faecalis, in the evolution of pancreatic inflammation. This study opens new research perspectives to investigate the pathophysiological mechanisms of intestinal microbiota species in the pancreatic exocrine tissue. Microbiota and metabolites produced by these microorganisms (like cytolysin) are probably key actors in the pancreatic inflammation process, involved in the cross-talk between the ​gut and pancreas. It could lead to consider potential new therapeutic targets in patients with chronic pancreatitis at risk of developing aggressive pancreatic cancers.

References

1. Ciocan D, Rebours V, Voican CS, Wrzosek L, Puchois V, Cassard AM, et al. Characterization of intestinal microbiota in alcoholic patients with and without alcoholic hepatitis or chronic alcoholic pancreatitis. Sci Rep. 19 mars 2018;8(1):4822.
2. Duan Y, Llorente C, Lang S, Brandl K, Chu H, Jiang L, et al. Bacteriophage targeting of gut bacterium attenuates alcoholic liver disease. Nature. nov 2019;575(7783):505‑11.