Type I interferon signaling in systemic immune cells from patients with alcoholic cirrhosis and its association with outcome

BACKGROUND & AIMS

In immune cells, constitutively and acutely produced type I interferons (IFNs) engage autocrine/paracrine signaling pathways to induce IFN-stimulated genes (ISGs). Enhanced activity of IFN signaling pathways can cause excessive inflammation and tissue damage. We aimed to investigate ISG expression in systemic immune cells from patients with decompensated alcoholic cirrhosis, and its association with outcome.

METHODS

Peripheral blood mononuclear cells (PBMCs) from patients and heathy subjects were stimulated or not with lipopolysaccharide (LPS, an IFN inducer) or increasing concentrations of IFN-β. The expression of 48 ISGs and ten "non-ISG" inflammatory cytokines were analyzed using RT-qPCR.

RESULTS

We developed an 8-ISG signature (IFN score) assessing ISG expression. LPS-stimulated ISG induction was significantly lower in PBMCs from patients with cirrhosis compared to healthy controls. Non-ISGs, however, showed higher induction. Lower induction of ISGs by LPS was not due to decreased IFN production by cirrhotic PBMCs or neutralization of secreted IFN, but a defective PBMC response to IFN. This defect was at least in part due to decreased constitutive ISG expression. Patients with the higher baseline IFN scores and ISG levels had the higher risk of death. At baseline, "non-ISG" cytokines did not correlate with outcome.

CONCLUSIONS

PBMCs from patients with decompensated alcoholic cirrhosis exhibit downregulated ISG expression, both constitutively and after an acute stimulus. Our finding that higher baseline PBMC ISG expression was associated with higher risk of death, suggests that constitutive ISG expression in systemic immune cells contributes to the prognosis of alcoholic cirrhosis.

LAY SUMMARY

Enhanced activity of IFN signaling pathways can cause excessive inflammation and tissue damage. Here we show that peripheral blood mononuclear cells (PBMCs) from patients with alcoholic cirrhosis exhibit a defect in interferon-stimulated genes (ISGs). We found that higher baseline ISG expression in PBMCs was associated with higher risk of death, revealing a probable contribution of ISG expression in immune cells to the outcome of alcoholic cirrhosis.

Long Wave Infrared Type II Superlattice Focal Plane Array Detector

The XBn/XBp family of barrier detectors enables diffusion limited dark currents comparable with HgxCd1-xTe Rule-07 and high quantum efficiencies. SCD’s XBp type II superlattice (T2SL) detector contains InAs/GaSb and InAs/AlSb T2SLs, and was designed for the long wave infrared (LWIR) atmospheric window using k · p based modeling of the energy bands and photo-response. Wafers are grown by molecular beam epitaxy and are fabricated into focal plane array (FPA) detectors using standard FPA processes, including wet and dry etching, indium bump hybridisation, under-fill, and back-side polishing. The 640 × 512 pixel, 15 μm pitch, detector goes by the name of ‘Pelican-D LW’ and exhibits a quantum efficiency of ~ 50 per cent with background limited performance at an operating temperature of 77 K. It has a cut-off wave length of ~ 9.5 μm, with a pixel operability of above 99 per cent. The detector gives a very stable image with a residual non uniformity of below 0.04 per cent over its useful dynamic range. A new digital read-out integrated circuit has been designed so that the complete detector closely follows the configuration of SCD’s MWIR Pelican-D detector.

Acute kidney injury in liver transplant candidates: a position paper on behalf of the Liver Intensive Care Group of Europe

INTRODUCTION

Acute kidney injury is associated with high mortality in the perioperative period of liver transplantation. The aim of this position paper was to provide an up-to-date overview with special emphases on diagnosis, risk factors, and treatment.

EVIDENCE ACQUISITION

The Liver Intensive Care Group of Europe nominated a panel of recognized international experts who reviewed the available literature published from 1990 to January 2016 and produced clinical recommendations. The level of evidence and strength of recommendation were judged according to the Grading of Recommendations Assessment Development and Evaluation system.

EVIDENCE SYNTHESIS

Diagnosis of AKI should be based on the KDIGO criteria. The preoperative risk factors are more related to the patient's predisposing factors and post-operative risk factors tend to be difficult to control. Therefore, focusing on intra-operative risk factors it would be important to maintain an adequate hemodynamics and to keep inferior vena cava clamping as short as possible. Biomarkers to identify AKI at an early stage are available; however, there is a lack of robust data that indicates their true beneficial effect. Intraoperative renal replacement therapy may be beneficial in some selective cases whereas its postoperative timing is still under debate.

CONCLUSIONS

Perioperative liver transplant risk factors for acute kidney injury are difficult to control. Therefore, the focus should be on intra-operative hemodynamics and nephrotoxic drugs avoidance. Prospective randomized trials are needed to show the beneficial effect of early replacement therapy. In this context, the new biomarkers would be helpful in identifying kidney injury earlier.

Prognosis of cirrhotic patients admitted to the general ICU

BACKGROUND

The prognosis of cirrhotic patients admitted to the ICU is considered to be poor but has been mainly reported in liver ICU. We aimed to describe the prognosis of cirrhotic patients admitted to a general ICU, to assess the predictors of mortality in this population, and, finally, to identify a subgroup of patients in whom intensive care escalation might be discussed.

RESULTS

We performed a retrospective monocentric study of all cirrhotic patients consecutively admitted between 2002 and 2014 in a general ICU in a regional university hospital. Two hundred and eighteen cirrhotic patients were admitted to the ICU. The 28-day and 6-month mortality rates were 53 and 74 %, respectively. Among the 115 patients who were discharged from ICU, only eight patients underwent liver transplantation, whereas 48 had no clear contraindication. Multivariable analyses on 28-day mortality identified three independent variables, incorporated into a new three-variable prognostic model as follows: SOFA ≥ 12 (OR 4.2 [2.2-8.0]; 2 points), INR ≥ 2.6 (OR 2.5 [1.3-4.8]; 1 point), and renal replacement therapy (OR 2.3 [1.1-5.1]; 1 point). For a value of the score at 4 (16 % of patients), 28-day and 3-month mortality rates were 91 and 100 %, respectively. An external validation of the score among 149 critically ill cirrhotic patients showed a good accuracy for predicting in-ICU mortality.

CONCLUSIONS

Mortality of cirrhotic patients admitted to a general ICU was comparable to that of other studies. A pragmatic score integrating the SOFA score, INR, and the need for extrarenal epuration was strongly associated with mortality. Among the 16 % of patients presenting with score 4 at ICU admission, 100 % died in the 3-month follow-up period. The prognostic evaluation on day 3 remains essential for the majority of patients. However, this score calculable at ICU admission might identify patients in whom the benefit of intensive care escalation should be discussed, in particular when liver transplantation is contraindicated.

Neutrophil gelatinase-associated lipocalin is a biomarker of acute-on-chronic liver failure and prognosis in cirrhosis

BACKGROUND & AIMS

Acute-on-chronic liver failure (ACLF) is a syndrome that occurs in cirrhosis characterized by organ failure(s) and high mortality rate. There are no biomarkers of ACLF. The LCN2 gene and its product, neutrophil gelatinase-associated lipocalin (NGAL), are upregulated in experimental models of liver injury and cultured hepatocytes as a result of injury by toxins or proinflammatory cytokines, particularly Interleukin-6. The aim of this study was to investigate whether NGAL could be a biomarker of ACLF and whether LCN2 gene may be upregulated in the liver in ACLF.

METHODS

We analyzed urine and plasma NGAL levels in 716 patients hospitalized for complications of cirrhosis, 148 with ACLF. LCN2 expression was assessed in liver biopsies from 29 additional patients with decompensated cirrhosis with and without ACLF.

RESULTS

Urine NGAL was markedly increased in ACLF vs. no ACLF patients (108(35-400) vs. 29(12-73)μg/g creatinine; p<0.001) and was an independent predictive factor of ACLF; the independent association persisted after adjustment for kidney function or exclusion of variables present in ACLF definition. Urine NGAL was also an independent predictive factor of 28day transplant-free mortality together with MELD score and leukocyte count (AUROC 0.88(0.83-0.92)). Urine NGAL improved significantly the accuracy of MELD in predicting prognosis. The LCN2 gene was markedly upregulated in the liver of patients with ACLF. Gene expression correlated directly with serum bilirubin and INR (r=0.79; p<0.001 and r=0.67; p<0.001), MELD (r=0.68; p<0.001) and Interleukin-6 (r=0.65; p<0.001).

CONCLUSIONS

NGAL is a biomarker of ACLF and prognosis and correlates with liver failure and systemic inflammation. There is remarkable overexpression of LCN2 gene in the liver in ACLF syndrome.

LAY SUMMARY

Urine NGAL is a biomarker of acute-on-chronic liver failure (ACLF). NGAL is a protein that may be expressed in several tissues in response to injury. The protein is filtered by the kidneys due to its small size and can be measured in the urine. Ariza, Graupera and colleagues found in a series of 716 patients with cirrhosis that urine NGAL was markedly increased in patients with ACLF and correlated with prognosis. Moreover, gene coding NGAL was markedly overexpressed in the liver tissue in ACLF.