Fulminant viral hepatitis

Intracranial pressure monitoring in the perioperative period of patients with acute liver failure undergoing orthotopic liver transplantation

Acute liver failure (ALF) may result in severe neurological complications caused by cerebral edema and elevated intracranial pressure (ICP). Multiple pathogenic mechanisms explain the elevated ICP, and newer hypotheses have been described. While invasive ICP monitoring (ICPM) may have a role in ALF management, these patients are typically coagulopathic and at risk for intracranial hemorrhage. ICPM is the subject of much debate, and significant heterogeneity exists in clinical practice regarding its use. Contemporary ICPM techniques and coagulopathy reversal strategies may be associated with a lower risk of hemorrhage; however, most of the evidence is limited by its retrospective nature and relatively small sample size.

Fulminant Viral Hepatitis in Two Siblings with Inherited IL-10RB Deficiency

Fulminant viral hepatitis (FVH) caused by hepatitis A virus (HAV) is a life-threatening disease that typically strikes otherwise healthy individuals. The only known genetic etiology of FVH is inherited IL-18BP deficiency, which unleashes IL-18-dependent lymphocyte cytotoxicity and IFN-γ production. We studied two siblings who died from a combination of early-onset inflammatory bowel disease (EOIBD) and FVH due to HAV. The sibling tested was homozygous for the W100G variant of IL10RB previously described in an unrelated patient with EOIBD. We show here that the out-of-frame IL10RB variants seen in other EOIBD patients disrupt cellular responses to IL-10, IL-22, IL-26, and IFN-λs in overexpression conditions and in homozygous cells. By contrast, the impact of in-frame disease-causing variants varies between cases. When overexpressed, the W100G variant impairs cellular responses to IL-10, but not to IL-22, IL-26, or IFN-λ1, whereas cells homozygous for W100G do not respond to IL-10, IL-22, IL-26, or IFN-λ1. As IL-10 is a potent antagonist of IFN-γ in phagocytes, these findings suggest that the molecular basis of FVH in patients with IL-18BP or IL-10RB deficiency may involve excessive IFN-γ activity during HAV infections of the liver. Inherited IL-10RB deficiency, and possibly inherited IL-10 and IL-10RA deficiencies, confer a predisposition to FVH, and patients with these deficiencies should be vaccinated against HAV and other liver-tropic viruses.

FGL2-MCOLN3-Autophagy Axis-Triggered Neutrophil Extracellular Traps Exacerbate Liver Injury in Fulminant Viral Hepatitis

BACKGROUND & AIMS

Fulminant viral hepatitis (FVH) is a life-threatening disease, but its pathogenesis is not fully understood. Neutrophil extracellular traps (NETs) were an unrecognized link between inflammation and coagulation, which are 2 main features of FVH. Here, we investigated the role and mechanism of NETs in the pathogenesis of FVH.

METHODS

A mouse model of FVH was established by murine hepatitis virus strain-3 infection. Liver leukocytes of infected or uninfected mice were used for single-cell RNA sequencing and whole-transcriptome sequencing. NETs depletion was achieved using DNase 1. Acetaminophen was used to establish a mouse model of non-virus-caused acute liver failure. Clinically, NETs-related markers in liver, plasma, and peripheral neutrophils were assessed in patients with hepatitis B virus (HBV)-related acute liver injury.

RESULTS

Increased hepatic NETs formation was observed in murine hepatitis virus strain-3-infected mice, but not in acetaminophen-treated mice. NETs depletion improved the liver damage and survival rate in FVH by inhibiting hepatic fibrin deposition and inflammation. An adoptive transfer experiment showed that neutrophil-specific fibrinogen-like protein 2 (FGL2) promoted NETs formation. FGL2 was found to directly interact with mucolipin 3, which regulated calcium influx and initiated autophagy, leading to NETs formation. Clinically, increased plasma NETs level was associated with coagulation dysfunction in patients with HBV acute liver injury. Colocalization of FGL2, NETs, and fibrin in liver was observed in these patients.

CONCLUSIONS

NETs aggravated liver injury in FVH by promoting fibrin deposition and inflammation. NETs formation was regulated by the FGL2-mucolipin 3-autophagy axis. Targeting NETs may provide a new strategy for the treatment of FVH.

Prognostic, clinical, and therapeutic importance of RANTES-CCR5 axis in hepatitis A infection: A multiapproach study

Fulminant hepatic failure (FHF) is a lethal manifestation of hepatitis A virus (HAV) infection, whose underlying mechanisms are poorly understood. We aimed to evaluate the importance of the modulation of the RANTES-chemokine receptor type 5 (CCR5) signaling axis and its immunomodulatory effects in directing hepatitis A disease pathogenesis using an in silico, in vitro and patient cohort-based approach. In silico interaction studies were performed using computation approaches with suitable software. Differential expression of relevant cytokines and immune cell markers were studied using real-time quantitative reverse transcription PCR (qRT-PCR), enzyme-linked immunosorbent assay, and flow-cytometry-based methods. In the HepG2 cell line, we studied inflammatory responses and susceptibility to HAV infection following RANTES stimulation and antibody blockade of CCR5. The HAV-VP3 region exhibited high interaction in CCR5: HAV complexes. RANTES levels were significantly increased in FHF cases. Reduced monocyte and T-cell activation were observed in FHF cases. RANTES expression inversely correlated with viremia but positively correlated with proinflammatory responses. Hyper Th1-biased immune responses, marked by high interleukin (IL)-12/IL-10 ratio were observed in FHF cases, which were also characterized by upregulated tumor necrosis factor-alpha (TNF-α) expression and reduced interferon-gamma expression. In vitro, RANTES was protective against HAV infection but resulted in upregulated TNF-α expression. Although viral load increased upon the regulation of inflammatory responses by CCR5 blocking, it was still significantly lower compared to control HAV-infected cells. Our study suggests the importance of RANTES-CCR5 signaling and linked-immunomodulation in HAV disease pathogenesis, as well as highlights the utility of CCR5 antagonists as a risk-reduction strategy in FHF patients. Our findings, therefore, have important implications for the management of high-risk HAV infections.

Pathophysiology of Acute Liver Failure

Acute liver failure (ALF) is a rare syndrome resulting from an acute insult to the liver in patients without known underlying chronic liver disease. It is characterized by loss of synthetic function in the form of jaundice and coagulopathy and development of hepatic encephalopathy. Multiorgan failure (MOF) eventually develops, leading to death. Many different etiologies have been identified, with acetaminophen (APAP) overdose and viral hepatitis being the most common causes worldwide. The pathophysiology of ALF can be divided into cause-specific liver injury pathophysiologies and pathophysiology related to occurrence of secondary MOF. In terms of liver injury pathophysiology, APAP toxicity is the most well known. Secondary MOF is often a result of the initial massive proinflammatory response generating a systemic inflammatory response syndrome followed by a compensatory anti-inflammatory response leading to immune cell dysfunction and sepsis. As the liver is a tremendously important metabolic organ involved in energy metabolism, protein synthesis, fat metabolism, and glycemic control, multiple aspects of nutrition also need to be considered as part of the overall pathophysiology of ALF.

Acute Liver Failure: From Textbook to Emergency Room and Intensive Care Unit With Concomitant Established and Modern Novel Therapies

Acute liver failure is a rare hepatic emergent situation that affects primarily young people and has often a catastrophic or even fatal outcome. Definition of acute liver failure has not reached a universal consensus and the interval between the appearance of jaundice and hepatic encephalopathy for the establishment of the acute failure is a matter of debate. Among the wide variety of causes, acetaminophen intoxication in western societies and viral hepatitis in the developing countries rank at the top of the etiology list. Identification of the clinical appearance and initial management for the stabilization of the patient are of vital significance. Further advanced therapies, that require intensive care unit, should be offered. The hallmark of treatment for selected patients can be orthotopic liver transplantation. Apart from well-established treatments, novel therapies like hepatocyte or stem cell transplantation, additional new therapeutic strategies targeting acetaminophen intoxication and/or hepatic encephalopathy are mainly experimental, and some of them do not belong, yet, to clinical practice. For clinicians, it is substantial to have the alertness to timely identify the patient and transfer them to a specialized center, where more treatment opportunities are available.

Complement System as a Target for Therapies to Control Liver Regeneration/Damage in Acute Liver Failure Induced by Viral Hepatitis

The complement system plays an important role in innate immunity inducing liver diseases as well as signaling immune cell activation in local inflammation regulating immunomodulatory effects such as liver damage and/or liver regeneration. Our aim is to evaluate the role of complement components in acute liver failure (ALF) caused by viral hepatitis, involving virus-induced ALF in human subjects using peripheral blood, samples of liver tissues, and ex vivo assays. Our findings displayed low levels of C3a in plasma samples with high frequency of C3a, C5a, and C5b/9 deposition in liver parenchyma. Meanwhile, laboratory assays using HepG2 (hepatocyte cell line) showed susceptibility to plasma samples from ALF patients impairing in vitro cell proliferation and an increase in apoptotic events submitting plasma samples to heat inactivation. In summary, our data suggest that the complement system may be involved in liver dysfunction in viral-induced acute liver failure cases using ex vivo assays. In extension to our findings, we provide insights into future studies using animal models for viral-induced ALF, as well as other associated soluble components, which need further investigation.

Changes in cellular proliferation and plasma products are associated with liver failure

AIM

To study the differences in immune response and cytokine profile between acute liver failure and self-limited acute hepatitis.

METHODS

Forty-six patients with self-limited acute hepatitis (AH), sixteen patients with acute liver failure (ALF), and twenty-two healthy subjects were involved in this study. The inflammatory and anti-inflammatory products in plasma samples were quantified using commercial enzyme-linked immunoassays and quantitative real-time PCR. The cellular immune responses were measured by proliferation assay using flow cytometry. The groups were divided into viral- and non-viral-induced self-limited AH and ALF. Thus, we worked with five groups: Hepatitis A virus (HAV)-induced self-limited acute hepatitis (HAV-AH), HAV-induced ALF (HAV-ALF), non-viral-induced self-limited acute hepatitis (non-viral AH), non-viral-induced acute liver failure (non-viral ALF), and healthy subjects (HC). Comparisons among HAV and non-viral-induced AH and ALF were performed.

RESULTS

The levels of mitochondrial DNA (mtDNA) and the cytokines investigated [interleukin (IL)-6, IL-8, IL-10, interferon gamma, and tumor necrosis factor] were significantly increased in ALF patients, independently of etiology (P < 0.05). High plasma mtDNA and IL-10 were the best markers associated with ALF [mtDNA: OR = 320.5 (95%CI: 14.42-7123.33), P < 0.0001; and IL-10: OR = 18.8 (95%CI: 1.38-257.94), P = 0.028] and death [mtDNA: OR = 12.1 (95%CI: 2.57-57.07), P = 0.002; and IL-10: OR = 8.01 (95%CI: 1.26-50.97), P = 0.027]. In the cellular proliferation assay, NK^bright, NKT and regulatory T cells (TReg) predominated in virus-specific stimulation in HAV-induced ALF patients with an anergic behavior in the cellular response to mitotic stimulation. Therefore, in non-viral-induced ALF, anergic behavior of activated T cells was not observed after mitotic stimulation, as expected and as described by the literature.

CONCLUSION

mtDNA and IL-10 may be predictors of ALF and death. TReg cells are involved in immunological disturbance in HAV-induced ALF.

Cynomolgus monkeys (Macaca fascicularis) experimentally infected with B19V and hepatitis A virus: no evidence of the co-infection as a cause of acute liver failure

This study was conducted to analyse the course and the outcome of the liver disease in the co-infected animals in order to evaluate a possible synergic effect of human parvovirus B19 (B19V) and hepatitis A virus (HAV) co-infection. Nine adult cynomolgus monkeys were inoculated with serum obtained from a fatal case of B19V infection and/or a faecal suspension of acute HAV. The presence of specific antibodies to HAV and B19V, liver enzyme levels, viraemia, haematological changes, and necroinflammatory liver lesions were used for monitoring the infections. Seroconversion was confirmed in all infected groups. A similar pattern of B19V infection to human disease was observed, which was characterised by high and persistent viraemia in association with reticulocytopenia and mild to moderate anaemia during the period of investigation (59 days). Additionally, the intranuclear inclusion bodies were observed in pro-erythroblast cell from an infected cynomolgus and B19V Ag in hepatocytes. The erythroid hypoplasia and decrease in lymphocyte counts were more evident in the co-infected group. The present results demonstrated, for the first time, the susceptibility of cynomolgus to B19V infection, but it did not show a worsening of liver histopathology in the co-infected group.

Validation of the Model for End-Stage Liver Disease Score Criteria in Urgent Liver Transplantation for Acute Flare Up of Hepatitis B

Acute flare up of hepatitis B in noncirrhotic liver with rapid liver function deterioration is a critical condition. This flare up of hepatitis B may be subsided under medical treatments, otherwise urgent liver transplantation is needed. However, the necessity of urgent liver transplantation is hard to decide. In this institute, the indications of urgent liver transplantation for acute flare up of hepatitis B in noncirrhotic liver were settled according to the model for end-stage liver disease (MELD) scores: once upon MELD scores ≥35 (criterion 1) or MELD score < 35 at beginning and increased in the subsequent 1 to 2 weeks (criterion 2). This study was to examine whether MELD score criteria for liver transplantation were valid in such an urgent condition. Eighty-three patients having acute flare up of hepatitis B virus with total bilirubin ≥17.5 mg/dL were included in this study. Among 83 patients, 20 patients met criterion 1. Five patients were transplanted and 15 patients died of liver failure with a median survival of 17 days. Fifty-one patients met criterion 2. Nineteen were transplanted, 30 patients died of liver failure with a median survival of 23.5 days, and 2 patients recovered from this critical condition. The other 12 patients did not meet criteria 1 and 2, and urgent liver transplantation was spared although 5 patients needed liver transplantation in subsequent 2 to 3 months. Therefore, the sensitivity of MELD score criteria for urgent liver transplantation was 100% and specificity was 85.7%. In conclusion, determination of urgent liver transplantation for hepatitis B with acute liver failure is crucial. MELD score criteria are valid to make a decision of urgent liver transplantation for hepatitis B patients with acute flare up and liver failure.

Micro RNAs mir-106a, mir-122 and mir-197 are increased in severe acute viral hepatitis with coagulopathy

BACKGROUND & AIMS

The severity of acute viral hepatitis, which may be caused by several distinct viruses, varies among individual patients. In rare cases, severe hepatic injury with sudden loss of liver function may occur, which is clinically indicated by the occurrence of coagulopathy or encephalopathy. As the molecular mechanisms of this liver injury are largely unknown, we investigated extracellular micro RNA (miRNA) profiles in 54 patients acutely infected with one of four different hepatotropic viruses, in order to identify those miRNAs which indicate severe viral hepatitis associated with coagulopathy.

METHODS

First, the profile of miRNAs was extensively analysed using a microarray-based approach in highly characterized 24 patients, matched in terms of sex, age and level of liver enzymes, as well as in three healthy controls. The cohort included samples from 18 patients with moderate and six individuals with severe hepatitis, indicated by abnormal prothrombin time and higher alanine aminotransferase and bilirubin levels. miRNAs found to be upregulated in severe hepatitis were then quantified by real-time PCR in the expanded cohort of 54 patients.

RESULTS

Comprehensive microarray-based miRNA profiling identified upregulation of mir-106a, mir-122 and mir-197 in patients with severe acute viral hepatitis with coagulopathy, as compared to patients who did not develop coagulopathy. mir-106a, mir-122 and mir-197 were then proven to be significantly upregulated in patients with severe acute viral hepatitis by quantitative real-time PCR (P < 0.01, Mann-Whitney U-test).

CONCLUSIONS

mir-106a, mir-122 and mir-197 could be potential markers for severe acute viral hepatitis associated with coagulopathy.

Cross-Sectional Study of Hepatitis A Virus Infection in the Pantanal Population before Vaccine Implementation in Brazil: Usage of Non-Invasive Specimen Collection

Population-based prevalence studies are essential tools for screening of hepatitis A and provide important data on susceptible groups. However, surveillance in isolated communities is difficult because of the limited access to these areas and the need for blood sample collection. This study aimed to determine the anti-HAV prevalence using oral fluid samples to provide an alternative tool for epidemiological studies that might be useful for vaccination-related decisions. The study population was composed of 224 volunteers from South Pantanal, aged 3 to 86 years old. This study was performed using oral fluids, previously standardized for anti-HAV antibody detection, which were collected using a ChemBio device. Eluates were tested using modified commercial EIA to detect anti-HAV antibodies. The overall prevalence was 79.1%, corresponding to 178 reactive EIA tests out of 224 samples. The age stratified data revealed a prevalence of 47.8% between 0–10 years, 84% in 11–20 years and 91.9% in subjects older than 21 years. Results indicate that hepatitis A prevalence was higher in adolescents and adults, corroborating the literature reports. Thus, oral fluid samples could replace serum in HAV epidemiological studies in isolated communities as they are efficient at detecting anti-HAV antibodies.

Genomic Diversity of Hepatitis B Virus Infection Associated With Fulminant Hepatitis B Development

CONTEXT

After five decades of Hepatitis B Virus (HBV) vaccine discovery, HBV is still a major public health problem. Due to the high genetic diversity of HBV and selective pressure of the host immune system, intra-host evolution of this virus in different clinical manifestations is a hot topic of research. HBV infection causes a range of clinical manifestations from acute to chronic infection, cirrhosis and hepatocellular carcinoma. Among all forms of HBV infection manifestations, fulminant hepatitis B infection possesses the highest fatality rate. Almost 1% of the acutely infected patients develop fulminant hepatitis B, in which the mortality rate is around 70%.

EVIDENCE ACQUISITION

All published papers deposited in Genbank, on the topic of fulminant hepatitis were reviewed and their virological aspects were investigated. In this review, we highlight the genomic diversity of HBV reported from patients with fulminant HBV infection.

RESULTS

The most commonly detected diversities affect regulatory motifs of HBV in the core and S region, indicating that these alterations may convert the virus to an aggressive strain. Moreover, mutations at T-cell and B-cell epitopes located in pre-S1 and pre-S2 proteins may lead to an immune evasion of the virus, likely favoring a more severe clinical course of infection. Furthermore, point and frame shift mutations in the core region increase the viral replication of HBV and help virus to evade from immune system and guarantee its persistence.

CONCLUSIONS

Fulminant hepatitis B is associated with distinct mutational patterns of HBV, underlining that genomic diversity of the virus is an important factor determining its pathogenicity.