Dysfunction of Circulating Polymorphonuclear Leukocytes and Monocytes in Ambulatory Cirrhotics Predicts Patient Outcome

Promising diagnostic biomarkers of nonalcoholic fatty liver disease and nonalcoholic steatohepatitis: From clinical proteomics to microbiome

Fatty liver has been present in the lives of patients and physicians for almost two centuries. Vast knowledge has been generated regarding its etiology and consequences, although a long path seeking novel and innovative diagnostic biomarkers for nonalcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH) is still envisioned. On the one hand, proteomics and lipidomics have emerged as potential noninvasive resources for NAFLD diagnosis. In contrast, metabolomics has been able to distinguish between NAFLD and NASH, even detecting degrees of fibrosis. On the other hand, genetic and epigenetic markers have been useful in monitoring disease progression, eventually functioning as target therapies. Other markers involved in immune dysregulation, oxidative stress, and inflammation are involved in the instauration and evolution of the disease. Finally, the fascinating gut microbiome is significantly involved in NAFLD and NASH. This review presents state-of-the-art biomarkers related to NAFLD and NASH and new promises that could eventually be positioned as diagnostic resources for this disease. As is evident, despite great advances in studying these biomarkers, there is still a long path before they translate into clinical benefits.

Risk of Severe Bacterial Infection in People Living Human Immunodeficiency Virus Infection in the Combined Antiretroviral Therapy Era

BACKGROUND

Severe bacterial infections are the first cause of morbidity in people with human immunodeficiency virus (PWH). We aimed to assess their incidence and to analyze their determinants.

METHODS

We studied human immunodeficiency virus (HIV)-1-infected individuals aged at least 15 years and prospectively followed between 2006 and 2015 in the French Hospital Database on HIV. The Andersen and Gill model was used to calculate the adjusted hazard ratios (HRs), focusing on heavy alcohol use and neutrophil function-altering comorbidities.

RESULTS

Of 25 795 participants, 1414 developed 1883 severe bacterial infections. Between 2006 and 2009 and 2013 and 2015, the incidence fell from 13.2 (95% confidence interval [CI], 12.3-14.1) to 7.1 (95% CI, 6.3-7.8) per 1000 person-years. Heavy alcohol use was associated with an increased risk of severe bacterial infection (HR = 1.3, 95% CI = 1.1-1.7 for 40-80 g/day and HR = 1.6, 95% CI = 1.2-2.1 for >80 g/day), as were diabetes, chronic kidney disease, and end-stage liver disease (HR = 1.2, 95% CI = 1.0-1.4 when 1 comorbidity; HR = 2.3, 95% CI = 1.6-3.4 when more than 1 comorbidity), and nonacquired immune deficiency syndrome-defining malignancy (HR = 2.0; 95% CI, 1.6-2.4).

CONCLUSIONS

Heavy alcohol use was associated with an increased risk of severe bacterial infection, as were neutrophil function-altering comorbidities. Controlled-drinking approaches should be promoted and comorbidity management should be strengthened in PWH.

Toll-like receptor 4 is a therapeutic target for prevention and treatment of liver failure

BACKGROUND & AIMS

Toll-like receptor 4 (TLR4) plays an essential role in mediating organ injury in acute liver failure (ALF) and acute-on-chronic liver failure (ACLF). Herein, we assess whether inhibiting TLR4 signaling can ameliorate liver failure and serve as a potential treatment.

METHODS

Circulating TLR4 ligands and hepatic TLR4 expression were measured in plasma samples and liver biopsies from patients with cirrhosis. TAK-242 (TLR4 inhibitor) was tested in vivo (10 mg/kg intraperitoneally) in rodent models of ACLF (bile duct ligation + lipopolysaccharide [LPS]; carbon tetrachloride + LPS) and ALF (galactosamine + LPS) and in vitro on immortalized human monocytes (THP-1) and hepatocytes (HHL5). The in vivo therapeutic effect was assessed by coma-free survival, organ injury and cytokine release and in vitro by measuring IL-6, IL-1β or cell injury (TUNEL), respectively.

RESULTS

In patients with cirrhosis, hepatic TLR4 expression was upregulated and circulating TLR4 ligands were increased (p <0.001). ACLF in rodents was associated with a switch from apoptotic cell death in ALF to non-apoptotic forms of cell death. TAK-242 reduced LPS-induced cytokine secretion and cell death (p = 0.002) in hepatocytes and monocytes in vitro. In rodent models of ACLF, TAK-242 administration improved coma-free survival, reduced the degree of hepatocyte cell death in the liver (p <0.001) and kidneys (p = 0.048) and reduced circulating cytokine levels (IL-1β, p <0.001). In a rodent model of ALF, TAK-242 prevented organ injury (p <0.001) and systemic inflammation (IL-1β, p <0.001).

CONCLUSION

This study shows that TLR4 signaling is a key factor in the development of both ACLF and ALF; its inhibition reduces the severity of organ injury and improves outcome. TAK-242 may be of therapeutic relevance in patients with liver failure.

LAY SUMMARY

Toll-like receptor 4 (or TLR4) mediates endotoxin-induced tissue injury in liver failure and cirrhosis. This receptor sensitizes cells to endotoxins, which are produced by gram-negative bacteria. Thus, inhibiting TLR4 signaling with an inhibitor (TAK-242) ameliorates organ injury and systemic inflammation in rodent models of acute and acute-on-chronic liver failure.

Systemic MCP-1 Levels Derive Mainly From Injured Liver and Are Associated With Complications in Cirrhosis

Background and Aims: Monocyte chemotactic protein-1 (MCP-1) is a potent chemoattractant for monocytes. It is involved in pathogenesis of several inflammatory diseases. Hepatic MCP-1 is a readout of macrophage activation. While inflammation is a major driver of liver disease progression, the origin and role of circulating MCP-1 as a biomarker remains unclear.

Methods: Hepatic CC-chemokine ligand 2 (CCL2) expression and F4/80 staining for Kupffer cells were measured and correlated in a mouse model of chronic liver disease (inhalative CCl₄ for 7 weeks). Next, hepatic RNA levels of CCL2 were measured in explanted livers of 39 patients after transplantation and correlated with severity of disease. Changes in MCP-1 were further evaluated in a rat model of experimental cirrhosis and acute-on-chronic liver failure (ACLF). Finally, we analyzed portal and hepatic vein levels of MCP-1 in patients receiving transjugular intrahepatic portosystemic shunt insertion for complications of portal hypertension.

Results: In this mouse model of fibrotic hepatitis, hepatic expression of CCL2 (P = 0.009) and the amount of F4/80 positive cells in the liver (P < 0.001) significantly increased after induction of hepatitis by CCl₄ compared to control animals. Moreover, strong correlation of hepatic CCL2 expression and F4/80 positive cells were seen (P = 0.023). Furthermore, in human liver explants, hepatic transcription levels of CCL2 correlated with the MELD score of the patients, and thus disease severity (P = 0.007). The experimental model of ACLF in rats revealed significantly higher levels of MCP-1 plasma (P = 0.028) and correlation of hepatic CCL2 expression (R = 0.69, P = 0.003). Particularly, plasma MCP-1 levels did not correlate with peripheral blood monocyte CCL2 expression. Finally, higher levels of MCP-1 were observed in the hepatic compared to the portal vein (P = 0.01) in patients receiving TIPS. Similarly, a positive correlation of MCP-1 with Child-Pugh score was observed (P = 0.018). Further, in the presence of ACLF, portal and hepatic vein levels of MCP-1 were significantly higher compared to patients without ACLF (both P = 0.039).

Conclusion: Circulating levels of MCP-1 mainly derive from the injured liver and are associated with severity of liver disease. Therefore, liver macrophages contribute significantly to disease progression. Circulating MCP-1 may reflect the extent of hepatic macrophage activation.

The immunological roles in acute-on-chronic liver failure: An update

BACKGROUND

Acute-on-chronic liver failure (ACLF) refers to the acute deterioration of liver function that occurs in patients with chronic liver disease. ACLF is characterized by acute decompensation, organ failure and high short-term mortality. Numerous studies have been conducted and remarkable progress has been made regarding the pathophysiology and pathogenesis of this disease in the last decade. The present review was to summarize the advances in this field.

DATA SOURCES

A comprehensive search in PubMed and EMBASE was conducted using the medical subject words "acute-on-chronic liver failure", "ACLF", "pathogenesis", "predictors", and "immunotherapy" combined with free text terms such as "systemic inflammation" and "immune paralysis". Relevant papers published before October 31, 2018, were included.

RESULTS

ACLF has two marked pathophysiological features, namely, excessive systemic inflammation and susceptibility to infection. The systemic inflammation is mainly manifested by a significant increase in the levels of plasma pro-inflammatory factors, leukocyte count and C-reactive protein. The underlying mechanisms are unclear and may be associated with decreased immune inhibitory cells, abnormal expression of cell surface molecules and intracellular regulatory pathways in immune cells and increased damage-associated molecular patterns in circulation. However, the main cause of susceptibility to infection is immune paralysis. Immunological paralysis is characterized by an attenuated activity of immune cells. The mechanisms are related to elevations of immune inhibitory cells and the concentration of plasma anti-inflammatory molecules. Some immune biological indicators, such as soluble CD163, are used to explore the pathogenesis and prognosis of the disease, and some immunotherapies, such as glucocorticoids and granulocyte colony-stimulating factor, are effective on ACLF.

CONCLUSIONS

Overwhelming systemic inflammation and susceptibility to infection are two key features of ACLF. A better understanding of the state of a patient's immune system will help to guide immunotherapy for ACLF.

NACSELD acute-on-chronic liver failure (NACSELD-ACLF) score predicts 30-day survival in hospitalized patients with cirrhosis

The North American Consortium for the Study of End-Stage Liver Disease's definition of acute-on-chronic liver failure (NACSELD-ACLF) as two or more extrahepatic organ failures has been proposed as a simple bedside tool to assess the risk of mortality in hospitalized patients with cirrhosis. We validated the NACSELD-ACLF's ability to predict 30-day survival (defined as in-hospital death or hospice discharge) in a separate multicenter prospectively enrolled cohort of both infected and uninfected hospitalized patients with cirrhosis. We used the NACSELD database of 14 tertiary care hepatology centers that prospectively enrolled nonelective hospitalized patients with cirrhosis (n = 2,675). The cohort was randomly split 60%/40% into training (n = 1,605) and testing (n = 1,070) groups. Organ failures assessed were (1) shock, (2) hepatic encephalopathy (grade III/IV), (3) renal (need for dialysis), and (4) respiratory (mechanical ventilation). Patients were most commonly Caucasian (79%) men (62%) with a mean age of 57 years and a diagnosis of alcohol-induced cirrhosis (45%), and 1,079 patients had an infection during hospitalization. The mean Model for End-Stage Liver Disease score was 19, and the median Child score was 10. No demographic differences were present between the two split groups. Multivariable modeling revealed that the NACSELD-ACLF score, as determined by number of organ failures, was the strongest predictor of decreased survival after controlling for admission age, white blood cell count, serum albumin, Model for End-Stage Liver Disease score, and presence of infection. The c-statistics were 0.8073 for the training set and 0.8532 for the validation set.

CONCLUSION

Although infection status remains an important predictor of death, NACSELD-ACLF was independently validated in a separate large multinational prospective cohort as a simple, reliable bedside tool to predict 30-day survival in both infected and uninfected patients hospitalized with a diagnosis of cirrhosis. (Hepatology 2018;67:2367-2374).