Circulating Elastin Fragments Are Not Affected by Hepatic, Renal and Hemodynamic Changes, But Reflect Survival in Cirrhosis with TIPS

Extrahepatic Surgery in Cirrhosis Significantly Increases Portal Pressure in Preclinical Animal Models

Background: Liver cirrhosis is a relevant comorbidity with increasing prevalence. Postoperative decompensation and development of complications in patients with cirrhosis remains a frequent clinical problem. Surgery has been discussed as a precipitating event for decompensation and complications of cirrhosis, but the underlying pathomechanisms are still obscure. The aim of this study was to analyze the role of abdominal extrahepatic surgery in cirrhosis on portal pressure and fibrosis in a preclinical model.

Methods: Compensated liver cirrhosis was induced using tetrachlormethane (CCL4) inhalation and bile duct ligation (BDL) models in rats, non-cirrhotic portal hypertension by partial portal vein ligation (PPVL). Intestinal manipulation (IM) as a model of extrahepatic abdominal surgery was performed. 2 and 7 days after IM, portal pressure was measured in-vivo. Hydroxyproline measurements, Sirius Red staining and qPCR measurements of the liver were performed for evaluation of fibrosis development and hepatic inflammation. Laboratory parameters of liver function in serum were analyzed.

Results: Portal pressure was significantly elevated 2 and 7 days after IM in both models of cirrhosis. In the non-cirrhotic model the trend was the same, while not statistically significant. In both cirrhotic models, IM shows strong effects of decompensation, with significant weight loss, elevation of liver enzymes and hypoalbuminemia. 7 days after IM in the BDL group, Sirius red staining and hydroxyproline levels showed significant progression of fibrosis and significantly elevated mRNA levels of hepatic inflammation compared to the respective control group. A progression of fibrosis was not observed in the CCL4 model.

Conclusion: In animal models of cirrhosis with continuous liver injury (BDL), IM increases portal pressure, and development of fibrosis. Perioperative portal pressure and hence inflammation processes may be therapeutic targets to prevent post-operative decompensation in cirrhosis.

Elective Surgery but not Transjugular Intrahepatic Portosystemic Shunt Precipitates Acute-On-Chronic Liver Failure

Acute-on-chronic liver failure (ACLF) is a syndrome associated with organ failure and high short-term mortality. Presence of ACLF at interventions, such as surgery or transjugular intrahepatic portosystemic shunt (TIPS), has been shown to determine outcome, but those interventions have also been attributed to precipitate ACLF in different studies. However, dedicated investigation for the risk of ACLF development in these interventions, especially in elective settings, has not been conducted. Patients with cirrhosis undergoing elective surgery were propensity score matched and compared to patients receiving TIPS. The primary endpoint was ACLF development within 28 days after the respective procedure. The secondary endpoint was 3-month and 1-year mortality. In total, 190 patients were included. Within 28 days, ACLF developed in 24% of the surgery and 3% of the TIPS cohorts, with the highest ACLF incidence between 3 and 8 days. By day 28 after the procedure, ACLF improved in the TIPS cohort. In both cohorts, patients developing ACLF within 28 days after surgery or TIPS placement showed significantly worse survival than patients without ACLF development at follow-up. After 12 months, mortality was significantly higher in the surgery cohort compared to the TIPS cohort (40% vs. 23%, respectively; P = 0.031). Regression analysis showed a European Foundation Chronic Liver Failure Consortium acute decompensation (CLIF-C AD) score ≥50 and surgical procedure as independent predictors of ACLF development. CLIF-C AD score ≥50, C-reactive protein, and ACLF development within 28 days independently predicted 1-year mortality. Conclusion: Elective surgical interventions in patients with cirrhosis precipitate ACLF development and ultimately death, but TIPS plays a negligible role in the development of ACLF. Elective surgery in patients with CLIF-C AD ≥50 should be avoided, while the window of opportunity would be CLIF-C AD <50.

Balance between macrophage migration inhibitory factor and sCD74 predicts outcome in patients with acute decompensation of cirrhosis

Background & Aims

Macrophage migration inhibitory factor (MIF) is an inflammatory cytokine and an important regulator of innate immune responses. We hypothesised that serum concentrations of MIF are associated with disease severity and outcome in patients with decompensated cirrhosis and acute-on-chronic liver failure (ACLF).

Methods

Circulating concentrations of MIF and its soluble receptor CD74 (sCD74) were determined in sera from 292 patients with acute decompensation of cirrhosis defined as new onset or worsening of ascites requiring hospitalisation. Of those, 78 (27%) had ACLF. Short-term mortality was assessed 90 days after inclusion.

Results

Although serum concentrations of MIF and sCD74 did not correlate with liver function parameters or ACLF, higher MIF (optimum cut-off >2.3 ng/ml) and lower concentrations of sCD74 (optimum cut-off <66.5 ng/ml) both indicated poorer 90-day transplant-free survival in univariate analyses (unadjusted hazard ratio [HR] 2.01 [1.26-3.22]; p = 0.004 for MIF; HR 0.59 [0.38-0.92]; p = 0.02 for sCD74) and after adjustment in multivariable models. Higher MIF concentrations correlated with surrogates of systemic inflammation (white blood cells, p = 0.005; C-reactive protein, p = 0.05) and were independent of genetic MIF promoter polymorphisms. Assessment of MIF plasma concentrations in portal venous blood and matched blood samples from the right atrium in a second cohort of patients undergoing transjugular intrahepatic portosystemic shunt insertion revealed a transhepatic MIF gradient with higher concentrations in the right atrial blood.

Conclusions

Serum concentrations of MIF and its soluble receptor CD74 predict 90-day transplant-free survival in patients with acute decompensation of cirrhosis. This effect was independent of liver function and genetic predispositions, but rather reflected systemic inflammation. Therefore, MIF and sCD74 represent promising prognostic markers beyond classical scoring systems in patients at risk of ACLF.

Lay summary

Inflammatory processes contribute to the increased risk of death in patients with cirrhosis and ascites. We show that patients with high serum levels of the inflammatory cytokine macrophage migration inhibitory factor (MIF) alongside low levels of its binding receptor sCD74 in blood indicate an increased mortality risk in patients with ascites. The cirrhotic liver is a relevant source of elevated circulating MIF levels.

Comprehensive assessment of ECM turnover using serum biomarkers establishes PBC as a high-turnover autoimmune liver disease

Background & Aims

Primary sclerosing cholangitis (PSC), primary biliary cholangitis (PBC) and autoimmune hepatitis (AIH) are phenotypically distinct autoimmune liver diseases that progress to cirrhosis and liver failure; however, their histological fibrosis distribution differs. We investigated the extracellular matrix (ECM) profiles of patients with PSC, PBC, and AIH to establish whether the diseases display differential patterns of ECM turnover.

Methods

Serum samples were retrospectively collected from the UK (test cohort; PSC n = 78; PBC n = 74; AIH n = 58) and Norway (validation cohort; PSC n = 138; PBC n = 28; AIH n = 27). Patients with ulcerative colitis without liver disease (n = 194) served as controls. We assessed specific serological biomarkers of ECM turnover: type III and V collagen formation (PRO-C3, PRO-C5), degradation of type III and IV collagen (C3M, C4M), biglycan (BGM) and citrullinated vimentin (VICM).

Results

Most of the ECM markers showed elevated serum levels in PBC compared with PSC or AIH (p <0.01). PRO-C3 correlated well with liver stiffness and showed the most striking differences between advanced and non-advanced liver disease; several of the other ECM markers were also associated with stage. PRO-C3 and other ECM markers were inversely associated with ursodeoxycholic acid treatment response in PBC and remission in AIH. All ECM remodelling markers were significantly elevated (p <0.05) in patients with PSC, PBC, or AIH compared with ulcerative colitis.

Conclusions

In this first study comparing ECM turnover in autoimmune liver diseases, we found increased ECM turnover in PBC compared with either PSC or AIH. The study indicates that ECM remodelling is different in PSC, PBC, and AIH, suggesting differing opportunities for therapeutic intervention.

Lay summary

The level of scarring is linked to prognosis in autoimmune liver diseases such as primary sclerosing cholangitis, primary biliary cholangitis, and autoimmune hepatitis; hence, the scarring process is a possible target for novel therapy. Investigating the scarring process using highly specific technology, we show that the scarring process is different between the 3 autoimmune liver diseases, and this may have important implications for the development of medical treatment.

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Serological biomarkers specifically targeting extracellular matrix remodelling enable evaluation of the dynamics of fibrosis evolution.

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ECM turnover was increased in PBC compared with PSC and AIH.

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ECM markers, particularly PRO-C3, were associated with disease stage in the autoimmune liver diseases and with clinical outcome in PSC.

Serological markers of extracellular matrix remodeling predict transplant-free survival in primary sclerosing cholangitis

BACKGROUND

Primary sclerosing cholangitis is a progressive liver disease with a remarkably variable course. Biomarkers of disease activity or prognostic models predicting outcome at an individual level are currently not established.

AIM

To evaluate the prognostic utility of four biomarkers of basement membrane and interstitial extracellular matrix remodeling in patients with primary sclerosing cholangitis.

METHODS

Serum samples were available from 138 large-duct primary sclerosing cholangitis patients (of which 102 [74%] with IBD) recruited 2008-2012 and 52 ulcerative colitis patients (controls). The median follow-up time was 2.2 (range 0-4.3) years. Specific biomarkers of type III and V collagen formation (PRO-C3 and PRO-C5, respectively) and type III and IV collagen degradation (C3M and C4M, respectively) were assessed. The Enhanced Liver Fibrosis test, including procollagen type III N-terminal peptide, tissue inhibitor of metalloproteinase-1 and hyaluronic acid was assessed for comparison.

RESULTS

All markers were elevated in primary sclerosing cholangitis compared to ulcerative colitis patients (P < 0.001). PRO-C3 showed the largest difference between the two groups with a threefold increase in primary sclerosing cholangitis compared to ulcerative colitis patients. Patients with high baseline serum levels of all markers, except C3M, had shorter survival compared to patients with low baseline serum levels (P < 0.001). Combining PRO-C3 and PRO-C5 the odds ratio for predicting transplant-free survival was 47 compared to the Enhanced Liver Fibrosis test's odds ratio of 11.

CONCLUSIONS

Extracellular matrix remodeling is elevated in primary sclerosing cholangitis patients compared to ulcerative colitis patients. Furthermore, the interstitial matrix marker PRO-C3 was identified as a potent prognostic marker and an independent predictor of transplant-free survival in primary sclerosing cholangitis.

Increase in liver stiffness after transjugular intrahepatic portosystemic shunt is associated with inflammation and predicts mortality

Transjugular intrahepatic portosystemic shunt (TIPS) efficiently treats complications of portal hypertension. Liver and spleen stiffness might predict clinically significant portal hypertension. This prospective study investigated liver stiffness in patients receiving TIPS regardless of indication. Of 83 included patients, 16 underwent transient elastography immediately before and 30 minutes after TIPS (acute group), while 67 received shear wave elastography of liver and spleen 1 day before and 7 days after TIPS (chronic group) and were followed further. In blood samples obtained before TIPS from cubital, portal, and hepatic veins, levels of several interleukins (IL1b, IL6, IL8, IL10, IL18) and interferon-gamma were analyzed. In 27 patients (5 acute, 22 chronic), it resulted in an increase in liver stiffness of >10%. In 56 patients, liver stiffness decreased or remained unchanged (<10%). Importantly, spleen stiffness measured by shear wave elastography decreased in all patients (chronic group). None of the clinical or laboratory parameters differed between patients with increase in liver stiffness and those without. Of note, patients with increased liver stiffness showed higher overall and/or hepatic venous levels of proinflammatory cytokines at TIPS and higher incidence of organ failure and worse survival after TIPS. C-reactive protein values and increase of >10% in liver stiffness after TIPS were the only independent predictors of mortality in these patients.

CONCLUSION

This study demonstrates that the presence of systemic inflammation predisposes patients to develop increased liver stiffness after TIPS, a predictor of organ failure and death. (NCT03072615) (Hepatology 2018;67:1472-1484).

Emergency TIPS in a Child-Pugh B patient: When does the window of opportunity open and close?

Transjugular intrahepatic portosystemic shunt (TIPS) is used to treat complications of cirrhosis such as variceal bleeding and refractory ascites, but it also bears the risk of liver failure, overt hepatic encephalopathy (HE) and cardiac decompensation. Variceal bleeding may be controlled using endoscopic and medical treatment in patients with compensated cirrhosis; in decompensated patients, however, TIPS improves survival. Therefore, an early TIPS (within 72h or if later, still early after bleeding) might improve the survival of patients by preventing an inflammatory response and bacterial translocation. Both these processes mediate an impaired immunological and hemodynamic response, thereby facilitating the development of acute-on-chronic liver failure (ACLF) and/or death. Similarly, in patients with refractory ascites, TIPS should be used early in treatment to prevent acute kidney injury (AKI) and hepatorenal syndrome (HRS) after precipitating events induced by complications of portal hypertension. Whether TIPS and/or embolization should be used to treat portal vein thrombosis and spontaneous shunts is still a matter of debate and should be further investigated. In summary, the careful selection of patients for TIPS is crucial. New biomarkers, especially those evaluating systemic inflammation and bacterial translocation, might improve the predictive value of established clinical parameters such as bilirubin and overt HE. However, a significant amount of further research must be carried out.

Protein degradation fragments as diagnostic and prognostic biomarkers of connective tissue diseases: understanding the extracellular matrix message and implication for current and future serological biomarkers

The aim of this review is to discuss the potential usefulness of novel biochemical markers of connective tissues: neo-epitopes of extracellular matrix proteins generated by post-translational modifications by tissue proteinases. As each modification results from a specific local physiological or pathobiological process, the identification of specific proteinase-mediated cleavage products of tissue-specific proteins may produce a unique disease-specific biochemical marker. The authors present a novel interpretation of the process of tissue degradation described by neo-epitope fragments of the interstitial and basement membrane matrix in fibrotic disease, and the diagnostic and prognostic potential of such markers. Moreover, the authors highlight the importance of matrix protein fragments not only as markers of tissue remodeling, but also as players in tissue remodeling, due to their signaling properties.

Elastin in the Liver

A characteristic feature of liver cirrhosis is the accumulation of large amounts of connective tissue with the prevailing content of type I collagen. Elastin is a minor connective tissue component in normal liver but it is actively synthesized by hepatic stellate cells and portal fibroblasts in diseased liver. The accumulation of elastic fibers in later stages of liver fibrosis may contribute to the decreasing reversibility of the disease with advancing time. Elastin is formed by polymerization of tropoelastin monomers. It is an amorphous protein highly resistant to the action of proteases that forms the core of elastic fibers. Microfibrils surrounding the core are composed of fibrillins that bind a number of proteins involved in fiber formation. They include microfibril-associated glycoproteins (MAGPs), microfibrillar-associated proteins (MFAPs) and fibulins. Lysyl oxidase (LOX) and lysyl oxidase-like proteins (LOXLs) are responsible for tropoelastin cross-linking and polymerization. TGF-β complexes attached to microfibrils release this cytokine and influence the behavior of the cells in the neighborhood. The role of TGF-β as the main profibrotic cytokine in the liver is well-known and the release of the cytokines of TGF-β superfamily from their storage in elastic fibers may affect the course of fibrosis. Elastic fibers are often studied in the tissues where they provide elasticity and resilience but their role is no longer viewed as purely mechanical. Tropoelastin, elastin polymer and elastin peptides resulting from partial elastin degradation influence fibroblastic and inflammatory cells as well as angiogenesis. A similar role may be performed by elastin in the liver. This article reviews the results of the research of liver elastic fibers on the background of the present knowledge of elastin biochemistry and physiology. The regulation of liver elastin synthesis and degradation may be important for the outcome of liver fibrosis.