Role of fibronectin and complement in immunopathogenesis of acute and subacute hepatic failure

Bioinformatic identification of key genes and pathways that may be involved in the pathogenesis of HBV-associated acute liver failure

In order to explore the molecular mechanisms behind the pathogenesis of acute liver failure (ALF) associated with hepatitis B virus (HBV) infection, the present study aimed to identify potential key genes and pathways involved using samples from patients with HBV-associated ALF. The GSE38941 array dataset was downloaded from the Gene Expression Omnibus database, and differentially expressed genes (DEGs) between 10 liver samples from 10 healthy donors and 17 liver specimens from 4 patients with HBV-associated ALF were analyzed using the Linear Models for Microarray Data package. Gene Ontology and KEGG pathway enrichment analyses of the DEGs were performed, followed by functional annotation of the genes and construction of a protein–protein interaction (PPI) network. Subnetwork modules were subsequently identified and analyzed. In total, 3142 DEGs were identified, of which 1755 were upregulated and 1387 were downregulated. The extracellular exosome, immune response, and inflammatory response pathways may potentially be used as biomarkers of ALF pathogenesis. In total, 17 genes (including CCR5, CXCR4, ALB, C3, VGEFA, and IGF1) were identified as hub genes in the PPI network and may therefore be potential marker genes for HBV-associated ALF.

Predictors of infection in viral-hepatitis related acute liver failure

OBJECTIVE

Infections are common and associated with complications and mortality in acute liver failure (ALF). The temporal relationship between ammonia and infection in ALF patients is unclear. We aimed to evaluate the predictors of infection and its relationship with arterial ammonia levels.

MATERIALS AND METHODS

Consecutive ALF patients hospitalized between January 2004 and December 2015, without signs of infection at/within 48 h of admission, were included. Occurrence of infection after 48 h was documented and ammonia levels were estimated for five consecutive days. Multivariate logistic regression analysis was used to assess factors associated with development of infection. Generalized estimating equations (GEE) were used to evaluate five-day time trend of ammonia in patients with and without infection.

RESULTS

Of 540 consecutive patients, 120 were infected at admission/within 48 h and were excluded. Of the rest 420 patients, 144 (34.3%) developed infection after 48 h and 276 (65.7%) remained non-infected. Infected patients had higher mortality than non-infected patients (61.8% vs 40.0%, p < .001). On multivariate analysis, presence of cerebral edema(HR 2.049; 95%CI, 1.30-3.23), ammonia level on day 3 of admission (HR 1.006; 95%CI, 1.003-1.008), and model for end stage liver disease (MELD) score (HR 1.051; 95%CI, 1.026-1.078) were associated with development of infection. GEE showed group difference in serial ammonia values between infected and non-infected patients indicating lack of ammonia decline in infected patients.

CONCLUSIONS

Cerebral edema, elevated ammonia on day 3, and higher MELD score predict the development of infection in ALF. Ammonia persists at high levels in infected patients, and elevated ammonia on day 3 is associated with complications and death.

Fibronectin predicts the outcome of acute-on-chronic hepatitis B liver failure

BACKGROUND

Acute-on-chronic hepatitis B liver failure (ACHBLF) is a serious condition with varied etiologies and manifestations, and is associated with a high mortality rate. Fibronectin is involved in a number of biological processes, including cellular adhesion, motility, differentiation, apoptosis, hemostasis, wound healing and ischemic injury. Serum fibronectin concentrations may provide prognostic information in ACHBLF; however, as a prognostic marker of mortality in patients with ACHBLF, it needs further validation.

METHODS

The aim of this study was to examine whether admission levels of fibronectin in ACHBLF patients are correlated with outcomes. In this prospective study, 78 ACHBLF patients were compared to 70 matched healthy controls. Fibronectin levels were determined using a commercial enzyme-linked immunosorbent assay kit to determine the prognostic value of fibronectin levels on admission.

RESULTS

The median (range) fibronectin level at admission for ACHBLF patients was significantly reduced compared with that of healthy controls (142 [62-275] mg/l vs 265 [190-346] mg/l, respectively; p<0.001). Fibronectin levels were significantly higher in surviving patients than in those who died (155 [70-275] mg/l vs 119 [62-235] mg/l; p=0.020). Receiver operating characteristic curve analysis showed that a cut-off level of 135 mg/l was the best prognostic indicator, yielding positive and negative predictive values of 60% (18/30) and 71% (30/42), respectively.

CONCLUSIONS

Our results suggested that decreased serum fibronectin levels in patients with ACHBLF were correlated to hepatic injury and inflammation. However, because of the lack of specificity, the use of fibronectin as an independent prognostic indicator is limited.

C3a and C3b Activation Products of the Third Component of Complement (C3) Are Critical for Normal Liver Recovery after Toxic Injury

Although the complement system has been implicated in liver regeneration after toxic injury and partial hepatectomy, the mechanism or mechanisms through which it participates in these processes remains ill-defined. In this study, we demonstrate that complement activation products (C3a, C3b/iC3b) are generated in the serum of experimental mice after CCl(4) injection and that complement activation is required for normal liver regeneration. Decomplementation by cobra venom factor resulted in impaired entry of hepatocytes into S phase of the cell cycle. In addition, livers from C3-deficient (C3(-/-)) mice showed similarly impaired proliferation of hepatocytes, along with delayed kinetics of both hepatocyte hyperplasia and removal of injured liver parenchyma. Restoration of hepatocyte proliferative capabilities of C3(-/-) mice through C3a reconstitution, as well as the impaired regeneration of C3a receptor-deficient mice, demonstrated that C3a promotes liver cell proliferation via the C3a receptor. These findings, together with data showing two waves of complement activation, indicate that C3 activation is a pivotal mechanism for liver regeneration after CCl(4) injury, which fulfills multiple roles; C3a generated early after toxin injection is relevant during the priming of hepatocytes, whereas C3 activation at later times after CCl(4) treatment contributes to the clearance of injured tissue.

Efficacy of interferon therapy on serum fibronectin levels in children with chronic hepatitis B infection

BACKGROUND

Fibronectin (FN) is a glycoprotein, the major sources of which are hepatocytes, Kupffer cells and endothelial cells. It has many biological functions including adhesion between cells, immunity, blood coagulation and platelet aggregation. Serum FN levels are generally decreased in pathological blood coagulation and inflammation. In the present study, we evaluated the serum levels of FN in patients with chronic hepatitis B virus (HBV) infection treated with interferon-alpha 2b.

METHODS

We studied serum levels of FN in a prospective trial between October 1995 and May 1997. The study included 16 patients with chronic HBV infection before and after interferon therapy, in a period of 6 months, and 17 healthy controls. In total, we had 40 patients with chronic HBV infection. We studied these 16 patients (40%) who recovered with interferon therapy. We could not study the other 24 patients because we did not have enough of the reagents for studying FN.

RESULTS

Chronic hepatitis B infection was diagnosed serologically and histopathologically. In mean age and sex, no statistically significant differences were found between patients and healthy subjects. The serum FN concentration before treatment with interferon therapy appeared significantly lower in HBV patients than in healthy control subjects (P = 0.026 using the Mann-Whitney confidence interval and test). After treatment with interferon, serum levels of FN were significantly higher than levels obtained before interferon therapy (P = 0.004 using the Wilcoxon Test).

CONCLUSIONS

These results suggest that a decreased level of serum FN in patients with chronic hepatitis before interferon treatment is related to hepatic injury and inflammation. Because of inflammation, the serum FN level is decreased due to the consumption of FN. Increased levels of serum FN in patients having interferon therapy is important and is related to the effects of interferon including antiviral, antiproliferative, anti-inflammatory and immunoregulatory properties in patients with chronic HBV infection. A Japanese study showed a correlation between development of hepatic fibrosis and decrease of plasma FN concentration in adult patients with chronic liver disease. Therefore, the serum level of FN may be a useful marker of hepatic fibrosis in chronic liver disease and interferon may be an important drug for prevention of liver fibrosis. Fibronectin may be also a useful marker in predicting IFN response.