Prospective study of bacterial infection in acute liver failure: an analysis of fifty patients

Soybean polyenylphosphatidylcholine (PPC) is beneficial in liver and extrahepatic tissue injury: An update in experimental research

Polyenylphosphatidylcholine (PPC) is a purified polyunsaturated phosphatidylcholine extract of soybeans. This article updates PPC's beneficial effects on various forms of liver cell injury and other tissues in experimental research. PPC downregulates hepatocyte CYP2E1 expression and associated hepatotoxicity, as well as attenuates oxidative stress, apoptosis, lipoprotein oxidation and steatosis in alcoholic and nonalcoholic liver injury. PPC inhibits pro-inflammatory cytokine production, while stimulating anti-inflammatory cytokine secretion in ethanol or lipopolysaccharide-stimulated Kupffer cells/macrophages. It promotes M2-type macrophage polarization and metabolic reprogramming of glucose and lipid metabolism. PPC mitigates steatosis in NAFLD through inhibiting polarization of pro-inflammatory M1-type Kupffer cells, alleviating metabolic inflammation, remodeling hepatic lipid metabolism, correcting imbalances between lipogenesis and lipolysis and enhancing lipoprotein secretion from hepatocytes. PPC is antifibrotic by preventing progression of alcoholic hepatic fibrosis in baboons and also prevents CCl4-induced fibrosis in rats. PPC supplementation replenishes the phosphatidylcholine content of damaged cell membranes, resulting in increased membrane fluidity and functioning. Phosphatidylcholine repletion prevents increased membrane curvature of the endoplasmic reticulum and Golgi and decreases sterol regulatory element binding protein-1-mediated lipogenesis, reducing steatosis. PPC remodels gut microbiota and affects hepatic lipid metabolism via the gut-hepatic-axis and also alleviates brain inflammatory responses and cognitive impairment via the gut-brain-axis. Additionally, PPC protects extrahepatic tissues from injury caused by various toxic compounds by reducing oxidative stress, inflammation, and membrane damage. It also stimulates liver regeneration, enhances sensitivity of cancer cells to radiotherapy/chemotherapy, and inhibits experimental hepatocarcinogenesis. PPC's beneficial effects justify it as a supportive treatment of liver disease.

Acute kidney injury in acute liver failure: A narrative review

Acute kidney injury (AKI) is a frequent complication of acute liver failure (ALF) and it worsens the already worse prognoses of ALF. ALF is an uncommon disease, with varying etiologies and varying definitions in different parts of the world. There is limited literature on the impact of AKI on the outcome of ALF with or without transplantation. The multifaceted etiology of AKI in ALF encompasses factors such as hemodynamic instability, systemic inflammation, sepsis and direct nephrotoxicity. Indications of renal replacement therapy (RRT) for AKI in ALF patients extend beyond the conventional criteria for dialysis and continuous renal replacement therapy (CRRT) may have a role in transplant-free survival or bridge to liver transplantation (LT). LT is a life-saving option for ALF, so despite somewhat lower survival rates of LT in ALF patients with AKI, LT is not usually deferred. In this review, we will discuss the guidelines' recommended definition and classification of AKI in ALF, the impact of AKI in ALF, the pathophysiology of AKI and the role of CRRT and LT in ALF patients with AKI.

Outcomes of critically ill patients with liver failure who require mechanical ventilation: A retrospective, single-center study

Background and Aims

Critically ill patients with liver failure have high mortality. Besides the management of organ-specific complications, liver transplantation constitutes a definitive treatment. However, clinicians may hesitate to introduce mechanical ventilation for patients on liver transplantation waitlists because of poor prognosis. This study investigated the outcomes of intensive care and ventilation support therapy effects in patients with liver failure.

Methods

This single-center study retrospectively enrolled 32 consecutive patients with liver failure who were admitted to the intensive care unit from January 2014 to December 2020. The medical records were reviewed and analyzed retrospectively for Acute Physiologic and Chronic Health Evaluation (APACHE)-II. The model for end-stage liver disease scores, 90-day mortality, and survival was assessed using the Kaplan-Meier method.

Results

The average patient age was 45.5 ± 20.1 years, and 53% of patients were women. On intensive care unit admission, APACHE-II and model for end-stage liver disease scores were 20 and 28, respectively. Among 13 patients considered for liver transplantation, 4 received transplants. Thirteen patients (40.6%) were intubated and mechanically ventilated in the intensive care unit. The 90-day mortality rate of patients with and without mechanical ventilation in the intensive care unit (13, 61.5% vs. 19, 47.4%, p = 0.4905) was similar. APACHE-II score >21 was an independent predictor of mechanical ventilation requirement in patients with liver failure during intensive care unit stay.

Conclusion

Although critically ill patients with liver failure are at risk of multiorgan failure with poor outcomes, mechanical ventilation did not negatively affect the 90-day mortality or performance rates of liver transplantation. Clinicians should consider mechanical ventilation-based life support in critically ill patients with liver failure who are awaiting liver transplantation.

Prevalence, Risk Factors, and Impact of Bacterial or Fungal Infections in Acute Liver Failure Patients from India

BACKGROUND

We evaluated the prevalence, risk factors, and impact of bacterial/fungal infections in acute liver failure (ALF) patients.

METHODS

We analyzed clinical, biochemical, and microbiological data of ALF patients with and without bacterial/fungal infections admitted at an institute over the last 5 years.

RESULTS

We enrolled 143 patients, 50% males, median age 25 years, with acute viral hepatitis (32.2%), drug-induced injury (18.2%), and tropical illness (14%) as aetiologies of ALF. 110 patients (76.9%) developed bacterial/fungal infections [Bacterial infection: MDR: 70%, PDR: 7%, ESBL: 40%, CRE: 30%, CRAB: 26.6%, MDR-EF: 13.3% and fungal infection: 19 (17.3%)]. On univariable analysis, SIRS (33.6% vs.3%), ICU admission (78.2% vs. 45.5%), mechanical ventilation (88.2% vs. 51.5%), inotropes (39.1% vs. 6.1%), invasive catheters (91.8% vs. 39.4%), and prolonged catheterization (6 days vs. 0 days) were significant risk factors for infections (p < 0.05, each). In contrast, SIRS and catheterization independently predicted infection on multivariable regression. Organ failures [3 (2-4) vs. 1 (0-2)], grade-III-IV HE (67.3% vs. 33.3%), circulatory failure (39.1% vs. 6.1%), coagulopathy (INR > 2.5: 58.2% vs. 33.3%), renal injury (28.2% vs. 6.1%) (p < 0.05), MELD (32.9 ± 8.2 vs. 26.7 ± 8.3) and CPIS [3(2-4) vs. 2(0-2)] were higher in infected vs. non-infected patients (p < 0.001). 30-day survival was significantly lower in infected vs. non-infected patients (17.3% vs. 75.8%, p < 0.001), while no patient survived with fungal infections. Refractory septic shock was the commonest cause of mortality in patients.

CONCLUSIONS

Infections due to MDR organisms are high, fungal infections are fatal, and refractory septic shock is the dominant reason for mortality, implying bacterial and fungal infections as the major killer in ALF patients.

Acute Liver Failure Guidelines

Acute liver failure (ALF) is a rare, acute, potentially reversible condition resulting in severe liver impairment and rapid clinical deterioration in patients without preexisting liver disease. Due to the rarity of this condition, published studies are limited by the use of retrospective or prospective cohorts and lack of randomized controlled trials. Current guidelines represent the suggested approach to the identification, treatment, and management of ALF and represent the official practice recommendations of the American College of Gastroenterology. The scientific evidence was reviewed using the Grading of Recommendations, Assessment, Development and Evaluation process to develop recommendations. When no robust evidence was available, expert opinions were summarized using Key Concepts. Considering the variety of clinical presentations of ALF, individualization of care should be applied in specific clinical scenarios.

Bacterial and fungal infections: a frequent and deadly complication among critically ill acute liver failure patients

BACKGROUND

Acute liver failure (ALF) is a rare but life-threatening condition mostly requiring intensive care unit (ICU) admission. ALF induces immune disorders and may promote infection acquisition. However, the clinical spectrum and impact on patients' prognosis remain poorly explored.

METHODS

We conducted a retrospective single-centre study on patients admitted for ALF to the ICU of a referral University Hospital from 2000 to 2021. Baseline characteristics and outcomes according to the presence of infection until day 28 were analysed. Risk factors for infection were determined using logistic regression. The impact of infection on 28-day survival was assessed using the proportional hazard Cox model.

RESULTS

Of the 194 patients enrolled, 79 (40.7%) underwent infection: community-acquired, hospital-acquired before ICU and ICU-acquired before/without and after transplant in 26, 23, 23 and 14 patients, respectively. Most infections were pneumonia (41.4%) and bloodstream infection (38.8%). Of a total of 130 microorganisms identified, 55 were Gram-negative bacilli (42.3%), 48 Gram-positive cocci (36.9%) and 21 were fungi (16.2%). Obesity (OR 3.77 [95% CI 1.18-14.40]; p = .03) and initial mechanical ventilation (OR 2.26 [95% CI 1.25-4.12]; p = .007) were independent factors associated with overall infection. SAPSII > 37 (OR 3.67 [95% CI 1.82-7.76], p < .001) and paracetamol aetiology (OR 2.10 [95% CI 1.06-4.22], p = .03) were independently associated with infection at admission to ICU. On the opposite, paracetamol aetiology was associated with lower risk of ICU-acquired infection (OR 0.37 [95% CI 0.16-0.81], p = .02). Patients with any type of infection had lower day 28 survival rates (57% versus 73%; HR 1.65 [1.01-2.68], p = .04). The presence of infection at ICU admission (p = .04), but not ICU-acquired infection, was associated with decreased survival.

CONCLUSIONS

The prevalence of infection is high in ALF patients which is associated with a higher risk of death. Further studies assessing the use of early antimicrobial therapy are needed.

Microalgae-Sustainable Source for Alternative Proteins and Functional Ingredients Promoting Gut and Liver Health

Dietary proteins derived from animal sources, although containing well-balanced profiles of essential amino acids, have considerable environmental and adverse health effects associated with the intake of some animal protein-based products. Consuming foods based on animal proteins carries a higher risk of developing non-communicable diseases such as cancer, heart disease, non-alcoholic fatty liver disease (NAFLD), and inflammatory bowel disease (IBD). Moreover, dietary protein consumption is increasing due to population growth, posing a supply challenge. There is, therefore, growing interest in discovering novel alternative protein sources. In this context, microalgae have been recognized as strategic crops that can provide a sustainable source of protein. Compared to conventional high-protein crops, using microalgal biomass for protein production presents several advantages in food and feed in terms of productivity, sustainability, and nutritional value. Moreover, microalgae positively impact the environment by not exploiting land or causing water pollution. Many studies have revealed the potential of microalgae as an alternative protein source with the added value of positive effects on human health due to their anti-inflammatory, antioxidant, and anti-cancer properties. The main emphasis of this review is on the potential health-promoting applications of microalgae-based proteins, peptides, and bioactive substances for IBD and NAFLD.

[Acute Liver Failure: Current Updates and Management]

Acute liver failure (ALF) is a rare disease condition with a dynamic clinical course and catastrophic outcomes. Several etiologies are involved in ALF. Hepatitis A and B infections and indiscriminate use of untested herbs or supplemental agents are the most common causes of ALF in Korea. Noninvasive neurological monitoring tools have been used in patients with ALF in recent times. Ongoing improvements in intensive care, including continuous renal replacement therapy, therapeutic plasma exchange, vasopressor, and extracorporeal membrane oxygenation, have reduced the mortality rate of patients with ALF. However, liver transplantation is still the most effective treatment for patients with intractable ALF. There is a need for further research in the areas of better prognostication and precise selection of patients for emergency transplantation.

Susceptibility to Infections During Acute Liver Injury Depends on Transient Disruption of Liver Macrophage Niche

Kupffer cells are the primary liver resident immune cell responsible for the liver firewall function, including clearance of bacterial infection from the circulation, as they are strategically positioned inside the liver sinusoid with intimate contact with the blood. Disruption in the tissue-resident macrophage niche, such as in Kupffer cells, can lead to a window of susceptibility to systemic infections, which represents a significant cause of mortality in patients with acetaminophen (APAP) overdose-induced acute liver injury (ALI). However, how Kupffer cell niche disruption increases susceptibility to systemic infections in ALI is not fully understood. Using a mouse model of ALI induced by APAP overdose, we found that Kupffer cells upregulated the apoptotic cell death program and were markedly reduced in the necrotic areas during the early stages of ALI, opening the niche for the infiltration of neutrophils and monocyte subsets. In addition, during the resolution phase of ALI, the remaining tissue macrophages with a Kupffer cell morphology were observed forming replicating cell clusters closer to necrotic areas devoid of Kupffer cells. Interestingly, mice with APAP-induced liver injury were still susceptible to infections despite the dual cellular input of circulating monocytes and proliferation of remaining Kupffer cells in the damaged liver. Therapy with bone marrow-derived macrophages (BMDM) was shown to be effective in occupying the niche devoid of Kupffer cells following APAP-induced ALI. The rapid BMDM migration to the liver and their positioning within necrotic areas enhanced the healing of the tissue and restored the liver firewall function after BMDM therapy. Therefore, we showed that disruption in the Kupffer cell niche and its impaired function during acute liver injury are key factors for the susceptibility to systemic bacterial infections. In addition, modulation of the liver macrophage niche was shown to be a promising therapeutic strategy for liver injuries that reduce the Kupffer cell number and compromise the organ function.

Emergencies in paediatric hepatology

The aetiology of several liver diseases in children is age specific and many of these conditions have significant and potentially long-term clinical repercussions if not diagnosed early and managed in a timely fashion. We address 5 clinical scenarios that cover most of the diagnostic and therapeutic emergencies in children: infants with liver disease; acute liver failure; management of bleeding varices; liver-based metabolic disorders; and liver tumours and trauma. A wide spectrum of conditions that cause liver disease in infants may present as conjugated jaundice, which could be the only symptom of time-sensitive disorders - such as biliary atresia, metabolic disorders, infections, and haematological/alloimmune disorders - wherein algorithmic multistage testing is required for accurate diagnosis. In infantile cholestasis, algorithmic multistage tests are necessary for an accurate early diagnosis, while vitamin K, specific milk formulae and disease-specific medications are essential to avoid mortality and long-term morbidity. Management of paediatric acute liver failure requires co-ordination with a liver transplant centre, safe transport and detailed age-specific aetiological work-up - clinical stabilisation with appropriate supportive care is central to survival if transplantation is indicated. Gastrointestinal bleeding may present as the initial manifestation or during follow-up in patients with portal vein thrombosis or chronic liver disease and can be managed pharmacologically, or with endoscopic/radiological interventions. Liver-based inborn errors of metabolism may present as encephalopathy that needs to be recognised and treated early to avoid further neurological sequelae and death. Liver tumours and liver trauma are both rare occurrences in children and are best managed by a multidisciplinary team in a specialist centre.

Oyster-Derived Tyr-Ala (YA) Peptide Prevents Lipopolysaccharide/D-Galactosamine-Induced Acute Liver Failure by Suppressing Inflammatory, Apoptotic, Ferroptotic, and Pyroptotic Signals

Models created by the intraperitoneal injection of lipopolysaccharide (LPS) and D-galactosamine (D-GalN) have been widely used to study the pathogenesis of human acute liver failure (ALF) and drug development. Our previous study reported that oyster (Crassostrea gigas) hydrolysate (OH) had a hepatoprotective effect in LPS/D-GalN-injected mice. This study was performed to identify the hepatoprotective effect of the tyrosine-alanine (YA) peptide, the main component of OH, in a LPS/D-GalN-injected ALF mice model. We analyzed the effect of YA on previously known mechanisms of hepatocellular injury in the model. LPS/D-GalN-injected mice showed inflammatory, apoptotic, ferroptotic, and pyroptotic liver injury. The pre-administration of YA (10 mg/kg or 50 mg/kg) significantly reduced the liver damage factors. The hepatoprotective effect of YA was higher in the 50 mg/kg YA pre-administered group than in the 10 mg/kg YA pre-administered group. These results showed that YA had a hepatoprotective effect by reducing inflammation, apoptosis, ferroptosis, and pyroptosis in the LPS/D-GalN-injected ALF mouse model. We suggest that YA can be used as a functional peptide for the prevention of acute liver injury.

Drug-induced liver injury at a tertiary care centre in Germany: Model for end-stage liver disease is the best predictor of outcome

BACKGROUND & AIMS

Agents most frequently inducing idiosyncratic drug-induced liver injury (DILI) differ between countries worldwide. Besides, there is no consistent data on the best model predicting mortality or the need for liver transplantation in DILI. We here analysed the DILI cohort of our centre with regard to causative drugs and clinical outcome.

METHODS

A retrospective analysis of 157 consecutive severe DILI patients presenting to our tertiary care centre in Hamburg, Germany, from 2008 to 2018, was performed.

RESULTS

The most frequent putatively causative drugs were phenprocoumon (n = 21), metamizole (n = 17) and flupirtine (n = 6). The mean values of ALT, bilirubin and Model for End-stage Liver Disease (MELD) score at the time of hospitalisation were 1201 U/L (SD: 1169 U/L), 6.8 mg/dL (SD: 7 mg/dL) and 17 (SD: 8). About 71% of all cases were treated with steroids or steroids combined with n-acetylcysteine. About 12.1% of all DILI cases had a poor outcome (liver transplantation and/or death). At the time of admission, MELD score performed better than Hy's law, the ratio (R) or the new ratio (nR) on their own or combined with bilirubin, regarding sensitivity or specificity for poor outcome. MELD score had a c-statistic of 0.847 (95% CI: 0.731-0.964). Furthermore, the cut-off of 18 MELD points had a sensitivity of 88% and a specificity of 72% for poor outcome.

CONCLUSION

Phenprocoumon and metamizole are frequent causative drugs for DILI in Germany. In comparison to other prognostic scores, MELD score ≥18 at the time of admission performed best in our cohort for the prediction of poor outcome in DILI.

Deletion or inhibition of SphK1 mitigates fulminant hepatic failure by suppressing TNFα-dependent inflammation and apoptosis

Acute liver failure (ALF) causes severe liver dysfunction that can lead to multi-organ failure and death. Previous studies suggest that sphingosine kinase 1 (SphK1) protects against hepatocyte injury, yet not much is still known about its involvement in ALF. This study examines the role of SphK1 in D-galactosamine (GalN)/lipopolysaccharide (LPS)-induced ALF, which is a well-established experimental mouse model that mimics the fulminant hepatitis. Here we report that deletion of SphK1, but not SphK2, dramatically decreased GalN/LPS-induced liver damage, hepatic apoptosis, serum alanine aminotransferase levels, and mortality rate compared to wild-type mice. Whereas GalN/LPS treatment-induced hepatic activation of NF-κB and JNK in wild-type and SphK2-/- mice, these signaling pathways were reduced in SphK1-/- mice. Moreover, repression of ALF in SphK1-/- mice correlated with decreased expression of the pro-inflammatory cytokine TNFα. Adoptive transfer experiments indicated that SphK1 in bone marrow-derived infiltrating immune cells but not in host liver-resident cells, contribute to the development of ALF. Interestingly, LPS-induced TNFα production was drastically suppressed in SphK1-deleted macrophages, whereas IL-10 expression was markedly enhanced, suggesting a switch to the anti-inflammatory phenotype. Finally, treatment with a specific SphK1 inhibitor ameliorated inflammation and protected mice from ALF. Our findings suggest that SphK1 regulates TNFα secretion from macrophages and inhibition or deletion of SphK1 mitigated ALF. Thus, a potent inhibitor of SphK1 could potentially be a therapeutic agent for fulminant hepatitis.

Sinapic acid ameliorates D-galactosamine/lipopolysaccharide-induced fulminant hepatitis in rats: Role of nuclear factor erythroid-related factor 2/heme oxygenase-1 pathways

BACKGROUND

Sinapic acid (SA) has been shown to have various pharmacological properties such as antioxidant, antifibrotic, anti-inflammatory, and anticancer activities. Its mechanism of action is dependent upon its ability to curb free radical production and protect against oxidative stress-induced tissue injuries.

AIM

To study the hepatoprotective effects of SA against lipopolysaccharide (LPS)/D-galactosamine (D-GalN)-induced acute liver failure (ALF) in rats.

METHODS

Experimental ALF was induced with an intraperitoneal (i.p.) administration of 8 μg LPS and 800 mg/kg D-GalN in normal saline. SA was administered orally once daily starting 7 d before LPS/D-GalN treatment.

RESULTS

Data showed that SA ameliorates acute liver dysfunction, decreases serum levels of alanine transaminase (ALT), and aspartate aminotransferase (AST), as well as malondialdehyde (MDA) and NO levels in ALF model rats. However, pretreatment with SA (20 mg/kg and 40 mg/kg) reduced nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) activation and levels of inflammatory cytokines (tumor necrosis factor-α and interleukin 6). Also, SA increased the activity of the nuclear factor erythroid-related factor 2/heme oxygenase-1 (Nrf2/HO-1) signaling pathway.

CONCLUSION

In conclusion, SA offers significant protection against LPS/D-GalN-induced ALF in rats by upregulating Nrf2/HO-1 and downregulating NF-κB.

Cell therapy for advanced liver diseases: Repair or rebuild

Advanced liver disease presents a significant worldwide health and economic burden and accounts for 3.5% of global mortality. When liver disease progresses to organ failure the only effective treatment is liver transplantation, which necessitates lifelong immunosuppression and carries associated risks. Furthermore, the shortage of suitable donor organs means patients may die waiting for a suitable transplant organ. Cell therapies have made their way from animal studies to a small number of early clinical trials. Herein, we review the current state of cell therapies for liver disease and the mechanisms underpinning their actions (to repair liver tissue or rebuild functional parenchyma). We also discuss cellular therapies that are on the clinical horizon and challenges that must be overcome before routine clinical use is a possibility.

Baicalein attenuates acute liver injury by blocking NLRP3 inflammasome

Infection and/or drug-mediated acute liver injury, the leading cause of lethal liver failure, is a critical health problem worldwide and lacks effective treatment. Here, we used Lipopolysaccharides (LPS)/D-galactosamine (D-gal)-treated primary hepatocytes to screen a natural library that contains 1130 chemicals. Baicalein in the library showed highest inhibitory effects against LPS/D-Gal-induced liver injury. In-vivo study similarly validated the protection of baicalein against dampened liver function and increased lethality after a challenge of LPS/D-Gal. Using a cytometric bead array, we found that IL-1α and IL-1β, the downstream of NLRP3, had highest reduction among the plasma inflammatory cytokines in LPS/D-Gal-challenged mice after a treatment of baicalein. To determine the target of baicalein and the underlying mechanism, Nlrp3^-/-, Gsdmd^-/- or WT mice were treated with or without baicalein, IL-1R antibody or recombinant mouse IL-1β (rmIL-1β) prior to a challenge of LPS/D-Gal. Deficiency of Nlrp3 or Gsdmd significantly restored LPS/D-Gal-induced acute liver injury and lethality, and further administration of baicalein did not have additive effects. In addition, the inhibition of the downstream by IL-1R antibody phenocopied the knockout of Nlrp3 or Gsdmd. Moreover, a challenge of rmIL-1β reversed the improvement in Nlrp3^-/- mice or the mice treated with baicalein. Taken together, NLRP3 functions as a pivotal promoter in acute liver injury and baicalein attenuates acute liver injury by inhibiting NLRP3 inflammasome.

Infectious complications and timing for liver transplantation in autoimmune acute liver failure in Japan: a subanalysis based on nationwide surveys between 2010 and 2015

BACKGROUND

The prognosis of autoimmune acute liver failure (ALF) without liver transplantation (LT) is poor worldwide. We subanalyzed infectious complications of autoimmune ALF using data of nationwide surveys between 2010 and 2015 retrospectively and tried to determine when to evaluate the efficacy of corticosteroid (CS) treatment or abandon it for LT based on objective data.

METHODS

One hundred and forty-four patients with autoimmune ALF, comprising 79 ALF with coma ≤ I, 52 ALF with coma ≥ II and 13 late onset hepatic failure (LOHF), were analyzed.

RESULTS

CS was administered to 140 (97%) patients. Thirty-seven (26%) patients had infectious complications. Patients with infection revealed more advanced disease type (p < 0.001) and poorer spontaneous survival (p < 0.001) than those without infection. Median (interquartile range) duration between diagnosis of ALF and onset of infection was 18.5 (11-36) days, and that between introduction of CS and onset of infection was 17 (10.5-36) days. Seventy-nine (55%) recovered without LT, 14 (10%) received LT and 51 (35%) died without LT. Dead or transplanted patients were older (p = 0.0057), and revealed more advanced liver failure (p < 0.001) and more occurrence of infection (p < 0.001).

CONCLUSIONS

A critical point for evaluating the efficacy of CS treatment and switching to LT is at most 2-week after diagnosis of ALF and introduction of CS. More important, we should accelerate the point and prepare for LT in cases of ALF with coma ≥ II and LOHF, and we should have performed LT by then at the latest in case of failure to improve.

Current concepts in acute liver failure

Acute liver failure (ALF) is a severe condition secondary to a myriad of causes associated with poor outcomes. The prompt diagnosis and identification of the aetiology allow the administration of specific treatments plus supportive strategies and to define the overall prognosis, the probability of developing complications and the need for liver transplantation. Pivotal issues are adequate monitoring and the institution of prophylactic strategies to reduce the risk of complications, such as progressive liver failure, cerebral oedema, renal failure, coagulopathies or infections. In this article, we review the main aspects of ALF, including the definition, diagnosis and complications. Also, we describe the standard-of-care strategies and recent advances in the treatment of ALF. Finally, we include our experience of care patients with ALF.

Alternatively activated macrophages promote resolution of necrosis following acute liver injury

BACKGROUND & AIM

Following acetaminophen (APAP) overdose, acute liver injury (ALI) can occur in patients that present too late for N-acetylcysteine treatment, potentially leading to acute liver failure, systemic inflammation, and death. Macrophages influence the progression and resolution of ALI due to their innate immunological function and paracrine activity. Syngeneic primary bone marrow-derived macrophages (BMDMs) were tested as a cell-based therapy in a mouse model of APAP-induced ALI (APAP-ALI).

METHODS

Several phenotypically distinct BMDM populations were delivered intravenously to APAP-ALI mice when hepatic necrosis was established, and then evaluated based on their effects on injury, inflammation, immunity, and regeneration. In vivo phagocytosis assays were used to interrogate the phenotype and function of alternatively activated BMDMs (AAMs) post-injection. Finally, primary human AAMs sourced from healthy volunteers were evaluated in immunocompetent APAP-ALI mice.

RESULTS

BMDMs rapidly localised to the liver and spleen within 4 h of administration. Injection of AAMs specifically reduced hepatocellular necrosis, HMGB1 translocation, and infiltrating neutrophils following APAP-ALI. AAM delivery also stimulated proliferation in hepatocytes and endothelium, and reduced levels of several circulating proinflammatory cytokines within 24 h. AAMs displayed a high phagocytic activity both in vitro and in injured liver tissue post-injection. Crosstalk with the host innate immune system was demonstrated by reduced infiltrating host Ly6C^hi macrophages in AAM-treated mice. Importantly, therapeutic efficacy was partially recapitulated using clinical-grade primary human AAMs in immunocompetent APAP-ALI mice, underscoring the translational potential of these findings.

CONCLUSION

We identify that AAMs have value as a cell-based therapy in an experimental model of APAP-ALI. Human AAMs warrant further evaluation as a potential cell-based therapy for APAP overdose patients with established liver injury.

LAY SUMMARY

After an overdose of acetaminophen (paracetamol), some patients present to hospital too late for the current antidote (N-acetylcysteine) to be effective. We tested whether macrophages, an injury-responsive leukocyte that can scavenge dead/dying cells, could serve as a cell-based therapy in an experimental model of acetaminophen overdose. Injection of alternatively activated macrophages rapidly reduced liver injury and reduced several mediators of inflammation. Macrophages show promise to serve as a potential cell-based therapy for acute liver injury.

Update on the management of acute liver failure

PURPOSE OF REVIEW

This review describes the current intensive care management of acute liver failure (ALF) and the latest evidence for emerging therapies.

RECENT FINDINGS

Mortality from ALF continues to improve and in some cases, medical therapy can negate the need for liver transplantation because of protocolized management in specialist centres. Liver transplantation remains the cornerstone of management for poor prognosis ALF. The reduced use of blood products in ALF reflects growing evidence of balanced haemostasis in severe liver disease. Prophylactic therapeutic hypothermia is no longer recommended for neuroprotection. In cases not suitable for liver transplantation, high-volume plasma exchange (HVP) has potential benefit, although further research on the optimal timing and dosing is needed. Although sepsis remains an important complication in ALF, the use of prophylactic antimicrobials is being questioned in the era of emerging bacterial resistance.

SUMMARY

ICU management of ALF has improved such that liver transplantation is not required in some cases. HVP has emerged as a potential therapy for patients who may not be good liver transplantation candidates. Nevertheless in suitable patients with poor prognosis liver transplantation remains the optimal therapy.

Tpl2 Protects Against Fulminant Hepatitis Through Mobilization of Myeloid-Derived Suppressor Cells

Myeloid derived suppressor cells (MDSC) in the liver microenvironment protects against the inflammation-induced liver injury in fulminant hepatitis (FH). However, the molecular mechanism through which MDSC is recruited into the inflamed liver remain elusive. Here we identified a protein kinase Tpl2 as a critical mediator of MDSC recruitment into liver during the pathogenesis of Propionibacterium acnes/LPS-induced FH. Loss of Tpl2 dramatically suppressed MDSC mobilization into liver, leading to exaggerated local inflammation and increased FH-induced mortality. Mechanistically, although the protective effect of Tpl2 for FH-induced mortality was dependent on the presence of MDSC, Tpl2 neither directly targeted myeloid cells nor T cells to regulate FH pathogenesis, but functioned in hepatocytes to mediate the induction of MDSC-attracting chemokine CXCL1 and CXCL2 through modulating IL-25 (also known as IL-17E) signaling. As a consequence, increased MDSC in the inflamed liver specifically restrained the local proliferation of infiltrated pathogenic CD4⁺ T cells, and thus protected against the inflammation-induced acute liver failure. Together, our findings established Tpl2 as a critical mediator of MDSC recruitment and highlighted the therapeutic potential of Tpl2 for the treatment of FH.

Amygdalin attenuates acute liver injury induced by D-galactosamine and lipopolysaccharide by regulating the NLRP3, NF-κB and Nrf2/NQO1 signalling pathways

Acute liver injury (ALI) is a life-threatening syndrome accompanied by overwhelming inflammation. Amygdalin (AGD) has been reported to possess various biological activities, particularly anti-inflammatory activity. The current study was designed to assess the protective effects and underlying mechanisms of AGD against ALI induced by d-galactosamine (GalN) and lipopolysaccharide (LPS) in mice. The results indicated that AGD treatment effectively reduced the lethality, ameliorated the histopathological liver changes, reduced the malondialdehyde (MDA) and myeloperoxidase (MPO) levels, and decreased the alanine transaminase (ALT) and aspartate aminotransferase (AST) levels resulting from LPS/GalN challenge. Moreover, AGD significantly inhibited LPS/GalN-induced inflammatory responses in mice with ALI by reducing not only the secretion of tumour necrosis factor (TNF)-α, interleukin (IL)-1β, and IL-6 but also the protein expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2). Additionally, our results demonstrated that the inhibitory effect of AGD was due to the suppressed activation of nuclear factor-kappa B (NF-κB) and nucleotide-binding domain (NOD-)like receptor protein 3 (NLRP3) inflammasome activity. Furthermore, AGD treatment substantially increased nuclear factor erythroid 2-related factor 2 (Nrf2) nuclear translocation and enhanced NAD (P) H: quinoneoxidoreductase 1 protein expression, which was reversed by a Nrf2 inhibitor, in HepG2 cells. In summary, our investigations suggested that the ability of AGD to ameliorate LPS/GalN-induced ALI may involve the inhibition of the NLRP3 inflammasome and NF-κB signalling pathways and the upregulation of the Nrf2/NQO1 signalling pathway.

Coagulation Failure in Patients With Acute-on-Chronic Liver Failure and Decompensated Cirrhosis: Beyond the International Normalized Ratio

Balanced hemostasis with hypocoagulable and hypercoagulable features may occur in acute-on-chronic liver failure (ACLF). The characteristics and prognostic impact of the coagulation profile in ACLF are unknown. Consecutive patients with ACLF (n = 36) and acute decompensation (AD; n = 24) were included. Blood samples for thromboelastometry (TE) were obtained at admission and 72 hours thereafter. The coagulation profile was evaluated in patients with and without ACLF and in those with and without systemic inflammatory response syndrome. The impact of the coagulation profile on transfusion requirements, bleeding events, and short-term survival was assessed. At admission, patients with ACLF showed more hypocoagulable characteristics compared to AD subjects, with prolonged time to initial fibrin formation and clot formation time and decreased maximum clot firmness and alpha-angle values. TE parameters worsened at 72 hours in ACLF but improved in patients with AD. Prevalence of a hypocoagulable profile (three or more TE parameters outside range) was significantly higher in patients with ACLF either at admission (61% versus 29% in AD; P = 0.03) or during follow-up. Hypocoagulability correlated with systemic inflammation and was associated with higher 28-day (45% versus 16%; P = 0.02) and 90-day (52% versus 19%; P = 0.01) mortality rates but not with transfusion requirements or bleeding. Prolonged time to initial fibrin formation (extrinsic TE assay >80 seconds) and Model for End-Stage Liver Disease score at baseline were independent predictors of 28-day mortality. Conclusion: Patients with ACLF frequently show hypocoagulable features with prolonged time to initial fibrin formation and clot formation time and reduced clot firmness; these alterations worsen after admission, correlate with systemic inflammation, and translate into higher short-term mortality; hypofibrinolysis could contribute to organ failure in ACLF.

Medical Management of Acute Liver Failure

Pediatric acute liver failure is a rapidly progressive, life-threatening, and devastating illness in children without preexisting liver disease. Due to the rarity and heterogeneity of this syndrome, there is a significant lack of data to guide evaluation and management of this disease. Most of our practice is extrapolated from adult literature and guidelines. This leads to significant controversies in medical management of acute liver failure in children. With advances in critical care, there has been a tremendous improvement in outcomes with decreased morbidity and mortality; however, there is a dire need for more research in this field. This chapter discusses challenges as well as controversies in diagnostic evaluation and management of this rare but potentially fatal disease. Latest developments in supportive care of liver failure, including advances in the area of liver support systems, are also discussed.

Respiratory Complications Before and After Liver Transplant

Respiratory complications before and after liver transplant are common, diverse, and potentially have a negative impact on patient outcomes. In this review, we discuss the most frequent respiratory conditions that patients may develop in the perioperative period. Their prevention and/or treatment may help to maximize the benefit these patients may derive from liver transplant. This review examines diagnostic and therapeutic approaches to these complications for hepatologists, surgeons, and critical care physicians.

Management of Acute Liver Failure: A Pediatric Perspective

Purpose of Review

Pediatric acute liver failure is a rare, complex, rapidly progressing, and life-threatening illness. Majority of pediatric acute liver failures have unknown etiology. This review intends to discuss the current literature on the challenging aspects of management of acute liver failure.

Recent Findings

Collaborative multidisciplinary approach for management of patients with pediatric acute liver failure with upfront involvement of transplant hepatologist and critical care specialists can improve outcomes of this fatal disease. Extensive but systematic diagnostic evaluation can help to identify etiology and guide management. Early referral to a transplant center with prompt liver transplant, if indicated, can lead to improved survival in these patients.

Summary

Prompt identification and aggressive management of pediatric acute liver failure and related comorbidities can lead to increased transplant-free survival and improved post-transplant outcomes, thus decreasing mortality and morbidity associated with this potential fatal condition.

The Clinical Spectrum and Manifestations of Acute Liver Failure

Acute liver failure (ALF) is a rare life-threatening condition characterized by rapid progression and death. Causes vary according to geographic region, with acetaminophen and drug-induced ALF being the most common causes in the United States. Determining the cause aids in predicting the prognosis and the presentation of manifestations and guides providers to perform cause-specific management. At initial presentation, nonspecific symptoms are present but may progress to complications, including cerebral edema, infection, coagulopathy, renal failure, cardiopulmonary failure, and acid-base and/or metabolic disturbances. Although some cases of ALF resolve with conservative measures, liver transplantation is the ultimate treatment in many cases.

Acute Liver Failure: Mechanisms of Disease and Multisystemic Involvement

Acute liver failure is accompanied by a pathologic syndrome common to numerous different etiologies of liver injury. This acute liver failure syndrome leads to potentially widespread devastating end-organ consequences. Systemic dysregulation and dysfunction is likely propagated via inflammation as well as underlying hepatic failure itself. Decoding the mechanisms of the disease process and multisystemic involvement of acute liver failure offers potential for targeted treatment opportunities and improved clinical outcomes in this sick population.

Prevalence and Impact of Bacterial Infections in Children With Liver Disease-A Prospective Study

BACKGROUND AND AIMS

Risk of infections is increased in patients with Acute Liver Failure (ALF) and Decompensated Chronic Liver Disease (DCLD). We evaluated the frequency, site, type and risk-factors for bacterial infections in children with ALF and DCLD and its effect on outcome.

METHODS

ALF or DCLD children were enrolled prospectively. Clinical and laboratory details were recorded. Cultures (blood, urine and ascites) and chest X-ray were done at admission followed by weekly surveillance cultures.

RESULTS

173 patients, 68 ALF and 105 DCLD were enrolled. Infections were more common in DCLD than ALF (60/105 [57.1%] vs. 27/68 [39.7%]; P = 0.02). Ascitic fluid infection, pneumonia, urinary tract infection and bacteremia were seen in 19%, 17.9%, 13.2% and 12.1% patients respectively. Healthcare-Associated (HCA) infections were most frequent (39/87, 44.8%), followed by Nosocomial (NC, 32%) and Community-Acquired (CA, 23%). Nearly 3/4th of bacterial isolates were resistant to cephalosporins and quinolones, 23% being Multiresistant Bacteria (MRB). DCLD patients with infection had higher Child-Pugh Score (10 [6-14] vs. 7 [6-14]; OR 3.2 [1.77-5.10]: P = 0.007), need for ICU care (26/60 vs. 3/45; OR 10.70 [2.98-38.42]: P = 0.01), in-hospital mortality (24/60 vs. 8/45;OR 3.08 [1.22-7.75]: P = 0.04) and mortality at 3 month follow-up (32/60 vs. 9/45; OR 4.57 [1.87-11.12]: P = 0.00). Infection did not affect the outcome in ALF.

CONCLUSION

Infections develop in 40% ALF and 57% DCLD children. HCA and NC infections account for 77% of infections. Most culture isolates are resistant to cephalosporins and fluoroquinolones and 23% have MRB. Risk of infections is higher in DCLD patients with advanced liver disease.

Bacterial Infection and Predictors of Mortality in Patients with Autoimmune Liver Disease-Associated Acute-On-Chronic Liver Failure

OBJECTIVE

To date, few studies are available on autoimmune liver disease-associated acute-on-chronic liver failure (ACLF). The aim of this study is to investigate bacterial infection and predictors of mortality in these patients.

METHODS

We retrospectively studied patients with autoimmune liver disease from August 2012 to August 2017. Clinical data of the patients were retrieved for analysis.

RESULTS

There were 53 ACLF patients and 53 patients without ACLF in this study. The ACLF group had a higher prevalence of complications (P < 0.05). The 28-day and 90-day mortality rates were also obviously high in patients with ACLF (38.3% and 74.5%, resp.) (P < 0.05). No predictor was significantly associated with 28-day and 90-day transplant-free mortality. In 53ACLF patients, 40 (75.5%) patients showed bacterial infection. ACLF patients with bacterial infection showed high Child-Pugh score, MELD score, CLIF-SOFA score, 28-day mortality, and 90-day mortality (P > 0.05). Moreover, C-reactive protein (CRP) using 12.15 mg/L cut-off value proved to be more accurate than procalcitonin in identifying patients with infection.

CONCLUSIONS

Autoimmune liver disease-associated ACLF showed more complications and high mortality. Bacterial infection patients displayed a more severe condition than those without infection. Elevated CRP is an accurate marker for diagnosing bacterial infection in autoimmune liver disease-associated ACLF patients.

Spred2 Deficiency Exacerbates D-Galactosamine/Lipopolysaccharide -induced Acute Liver Injury in Mice via Increased Production of TNFα

Acute liver injury (ALI) is characterized by hepatocyte damage and inflammation. In the present study, we examined whether the absence of Sprouty-related EVH1-domain-containing protein 2 (Spred2), a negative regulator of the Ras/Raf/ERK/MAPK pathway, influences ALI induced by D-galactosamine (D-GalN) and lipopolysaccharide (LPS). Compared to wild-type mice, Spred2^−/− mice developed exacerbated liver injury represented by enhanced hepatocyte damage and inflammation. Enhanced ERK activation was observed in Spred2^−/−-livers, and the MEK/ERK inhibitor U0126 ameliorated ALI. Hepatic tumour necrosis factor α (TNFα) and interleukin (IL)-1β levels were increased in Spred-2^−/−-livers, and the neutralization of TNFα dramatically ameliorated ALI, which was associated with decreased levels of endogenous TNFα and IL-1β. When mice were challenged with D-GalN and TNFα, much severer ALI was observed in Spred2^−/− mice with significant increases in endogenous TNFα and IL-1β in the livers. Immunohistochemically, Kupffer cells were found to produce TNFα, and isolated Kupffer cells from Spred2^−/− mice produced significantly higher levels of TNFα than those from wild-type mice after LPS stimulation, which was significantly decreased by U0126. These results suggest that Spred2 negatively regulates D-GalN/LPS-induced ALI under the control of TNFα in Kupffer cells. Spred2 may present a therapeutic target for the treatment of ALI.

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.

Autoimmune acute liver failure and seronegative autoimmune liver disease in children: Are they different from classical disease?

OBJECTIVES

Presentation as autoimmune acute liver failure (AI-ALF) and seronegative autoimmune liver disease (SN-AILD) represents two uncommon variants of AILD. We compared the clinical profile and outcome of AI-ALF with autoimmune-non-acute liver failure (AI-non-ALF) and also SN-AILD with seropositive autoimmune liver disease (SP-AILD).

MATERIALS AND METHODS

Children managed as AI-ALF and AI-non-ALF including SN-AILD and SP-AILD were enrolled and compared. AI-non-ALF was diagnosed by simplified diagnostic criteria and AI-ALF by Pediatric Acute Liver Failure Study Group criteria with positive autoantibody, exclusion of other etiologies, elevated immunoglobulin G and histology when available.

RESULTS

Seventy children [AI-ALF=15 and AI-non-ALF=55 (SN-AILD=11, SP-AILD=44)] were evaluated. Age at presentation [7 (1.2-16) vs. 9 (2-17) years] percentage of female patients (67 vs. 62%), and AILD type (type II, 53 vs. 31%) were similar in AI-ALF and AI-non-ALF patients], respectively. 8/15 AI-ALF cases were treated with steroids (improved-4, liver transplant-1, and death-3) and 7/15 died before initiation of therapy. Hepatic encephalopathy (100 vs. 16.3%; P<0.001), massive hepatic necrosis (60 vs. 0%; P<0.001), and higher pediatric end-stage liver disease [n=53, 29.9 (13.1-56.9) vs. 9.8 (-10-28.7) P<0.001], model for end-stage liver disease [n=17, 38.5 (24-46) vs. 18 (6-24); P=0.005], and Child-Turcotte-Pugh [n=70, 13 (8-13) vs. 9 (5-13); P<0.001] scores were features of AI-ALF. Poorer response to immunosuppression (4/8 vs. 48/55; P=0.02) and higher mortality (11/15 vs. 4/55; P=0.0001) were seen in AI-ALF than in AI-non-ALF patients. Clinicolaboratory profile, therapeutic response, and outcome were similar in SN-AILD and SP-AILD.

CONCLUSION

AI-ALF is characterized by poorer liver function, lower response to immunosuppression, and higher mortality compared with SP or SN AI-non-ALF, which are similar.

Acute Liver Failure

Acute liver failure (ALF) is a life-threatening condition of heterogeneous etiology. Outcomes are better with early recognition and prompt initiation of etiology-specific therapy, intensive care protocols, and liver transplantation (LT). Prognostic scoring systems include the King's College Criteria and Model for End-stage Liver Disease score. Cerebral edema and intracranial hypertension are reasons for high morbidity and mortality; hypertonic saline is suggested for patients with a high risk for developing intracranial hypertension, and when it does, mannitol is recommended as first-line therapy. Extracorporeal liver support system may serve as a bridge to LT and may increase LT-free survival in select cases.

Intensive Care Management of Pediatric Acute Liver Failure

Pediatric acute liver failure is rare but life-threatening illness that occurs in children without preexisting liver disease. The rarity of the disease, along with its severity and heterogeneity, presents unique clinical challenges to the physicians providing care for pediatric patients with acute liver failure. In this review, practical clinical approaches to the care of critically ill children with acute liver failure are discussed with an organ system-specific approach. The underlying pathophysiological processes, major areas of uncertainty, and approaches to the critical care management of pediatric acute liver failure are also reviewed.

Role of N-acetylcysteine treatment in non-acetaminophen-induced acute liver failure: A prospective study

BACKGROUND/AIMS

Acute liver failure (ALF) is a rare but severe medical emergency. To date, there is no established treatment for non-acetaminophen-induced acute liver failure (NAI-ALF) other than liver transplantation, and little is known about the use of N-acetylcysteine (NAC) in NAI-ALF. A randomized case control study was conducted with the aim to determine the effect of NAC on the mortality of NAI-ALF patients, as well as to evaluate the safety and efficacy of NAC use.

PATIENTS AND METHODS

A total of 80 patients diagnosed with NAI-ALF were included in the study. Forty patients received NAC infusion for 72 h whereas the control group received placebo. The variables evaluated were demographic characteristics, signs and symptoms, biochemical parameters, and clinical course during hospitalization.

RESULTS

The two groups (NAC and control) were comparable for various baseline characteristics (such as etiology of ALF, INR, alanine aminotransferase, creatinine, albumin, and grade of encephalopathy), except for age. Although majority of patients had undetermined etiology (32.5% in NAC group and 42.5% in control group), the second main cause was acute hepatitis E and drug or toxin-induced ALF. The mortality decreased to 28% with the use of NAC versus 53% in the control group (P = 0.023). The use of NAC was associated with shorter length of hospital stay in survived patients (P = 0.002). Moreover, the survival of patients was improved by NAC (P = 0.025). Also, drug-induced ALF showed improved outcome compared to other etiologies.

CONCLUSION

The findings of the study recommend the use of NAC along with conventional treatments in patients with NAI-ALF in non-transplant centers while awaiting referrals and conclude the use of NAC as safe.

Drug-Induced Acute Liver Failure

Drug-induced acute liver failure (ALF) disproportionately affects women and nonwhites. It is most frequently caused by antimicrobials and to a lesser extent by complementary and alternative medications, antiepileptics, antimetabolites, nonsteroidals, and statins. Most drug-induced liver injury ALF patients have hepatocellular injury pattern. Cerebral edema and intracranial hypertension are the most serious complications of ALF. Other complications include coagulopathy, sepsis, metabolic derangements, and renal, circulatory, and respiratory dysfunction. Although advances in intensive care have improved outcome, ALF has significant mortality without liver transplantation. Liver-assist devices may provide a bridge to transplant or to spontaneous recovery.

Acute Liver Injury and Failure

Acute liver injury and acute liver failure are syndromes characterized by a rapid loss of functional hepatocytes in a patient with no evidence of pre-existing liver disease. A variety of inciting causes have been identified, including toxic, infectious, neoplastic, and drug-induced causes. This article reviews the pathophysiology and clinical approach to the acute liver injury/acute liver failure patient, with a particular emphasis on the diagnostic evaluation and care in the acute setting.

Toxicant-Induced Hepatic Injury

The sudden failure of a previously healthy and functioning liver is a dramatic and devastating event. Acute liver failure is the common final pathway of a multitude of conditions and insults, all of which result in massive hepatic necrosis or loss of normal hepatic function. The ensuing multiorgan system failure frequently has a fatal outcome, with mortality rates in most series ranging from approximately 55% to 95% [1]. Acute liver failure (ALF, previously often referred to as fulminant hepatic failure (FHF)) knows no age boundaries, with many cases occurring in those younger than 30 years. Short of excellent intensive care unit (ICU) support and liver transplantation in selected cases, few viable treatment options are available. Over the past few decades, however, survival has been improved by anticipation, recognition, and early treatment of associated complications, as well as the application of prognostic criteria for early identification of patients requiring liver transplantation (along with improvement in the techniques and science of transplantation itself). The etiology of ALF varies from country to country and the incidence change over time. Paracetamol (acetaminophen) has now replaced viral hepatitis as the leading cause of ALF [2]. In a study from London including 310 patients with ALF in the period 1994–2004, 42% of the cases were caused by paracetamol [3], whereas this was only the cause in 2% of 267 patients in Spain from 1992 to 2000 [4]. However, less than 10% of all liver transplants are performed in patients with ALF [5, 6].

Data-Driven Modeling for Precision Medicine in Pediatric Acute Liver Failure

Absence of early outcome biomarkers for Pediatric Acute Liver Failure (PALF) hinders medical and liver transplant decisions. We sought to define dynamic interactions among circulating inflammatory mediators to gain insights into PALF outcome sub-groups. Serum samples from 101 participants in the PALF study, collected over the first 7 days following enrollment, were assayed for 27 inflammatory mediators. Outcomes (Spontaneous survivors [S, n=61], Non-survivors [NS, n=12], and liver transplant patients [LTx, n=28]) were assessed at 21 days post-enrollment. Dynamic interrelations among mediators were defined using data-driven algorithms. Dynamic Bayesian Network inference identified a common network motif with HMGB1 as a central node in all patient sub-groups. The networks in S and LTx were similar, and differed from NS. Dynamic Network Analysis suggested similar dynamic connectivity in S and LTx, but a more highly-interconnected network in NS that increased with time. A Dynamic Robustness Index calculated to quantify how inflammatory network connectivity changes as a function of correlation stringency differentiated all three patient sub-groups. Our results suggest that increasing inflammatory network connectivity is associated with non-survival in PALF, and may ultimately lead to better patient outcome stratification.

Infectious complications, steroid use and timing for emergency liver transplantation in acute liver failure: analysis in a Japanese center

BACKGROUND

Corticosteroid (CS) has been introduced in most acute liver failure (ALF) patients for the purpose of suppressing pro-inflammatory cytokines in Japan where a shortage of donor livers exists, whereas CS use is evaluated to be no benefit in Western countries. In the present study, we aimed to clarify the association between infectious complications and CS use in ALF, and determine when to evaluate treatment response and consider the timing for switching to liver transplantation (LT).

METHODS

Corticosteroid was administered to patients in the early stage prospectively. Clinical and biochemical features of 110 adult patients were analyzed.

RESULTS

Corticosteroids were administered to 78 (71%) patients. The duration between start of CS and onset of infection was 17 ± 10 days. Multivariate analysis revealed that infection was associated with age >50 years (P = 0.034) and T-BIL >15 mg/dl (P < 0.001), and not with CS use (P = 0.10). Accumulative incidence of infection was not different between patients with and without CS (P = 0.18).

CONCLUSIONS

Corticosteroid use did not significantly increase the incidence of infection. Two weeks after introduction of CS is a critical point for evaluating treatment response, avoiding infectious complications and switching to LT.

Role of Procalcitonin and C-Reactive Protein As Biomarkers of Infection in Children With Liver Disease

OBJECTIVES

Early and accurate identification of infection in patients with liver disease is challenging. The present study evaluated the role of procalcitonin (PCT) and C-reactive protein (CRP) as biomarkers of bacterial infection in children with liver disease.

METHODS

Demographic and clinical data of consecutive children admitted with acute liver failure (ALF) or decompensated chronic liver disease (DCLD) were collected. PCT and CRP were measured within 24 hours of admission. Blood and urine culture, chest x-ray, and ascitic fluid analysis were done.

RESULTS

One hundred sixty-four children (113 boys, age 76 [0.5-204] months, ALF 69, DCLD 95) were enrolled. Seventy-seven (47%) had infection. Most common site was ascitic fluid (n = 35), followed by urinary tract (n = 26), pneumonia (n = 22), and blood stream infection (n = 16). Twenty-one children had multiple-site infections, 18 had severe sepsis, and 36 had systemic inflammatory response syndrome. PCT and CRP correlated with infection severity, higher in severe sepsis (8.3 [3.5-38] ng/mL and 4.1 [0.3-13.8] mg/dL) than only infection (0.89 [0.1-8] ng/mL and 1.7 [0.32-24] mg/dL) and no infection (0.3 [0.1-6.75] ng/mL and 0.3 [0.1-4.16 mg/dL]). Systemic inflammatory response syndrome was more common in patients with infection (31/77 vs 5/87, P = 0.00). PCT (>0.5 ng/mL) and CRP (>0.6 mg/dL) performed better in DCLD (AUC of 0.90 and 0.83) compared with patients with ALF (AUC of 0.73 and 0.69).

CONCLUSIONS

PCT and CRP are reliable markers of infection and correlate with infection severity in children with liver disease. Their diagnostic accuracy is better in DCLD than ALF cases.

Prognostic significance of infections in critically ill adult patients with acute liver injury: a retrospective cohort study

BACKGROUND AND AIMS

Patients with acute liver failure have high rates of infections, likely from defects in immune function. Whether infections are independently associated with poor outcomes is unclear. We hypothesized that patients with acute liver injury who developed infections were at increased risk of adverse outcomes.

METHODS

We conducted a retrospective analysis of 150 critically ill adult patients admitted with acute liver dysfunction at a single academic institution between 2005 and 2011. We excluded patients with immunocompromised states, patients with chronic liver disease and patients who died or were discharged within 48 h of admission. Our primary endpoint was a 30-day event-free survival, with events defined as either death or liver transplantation. Our secondary endpoint was length of stay. Univariate and multivariate analyses were performed to determine associations between presence of infection and our primary and secondary endpoints.

RESULTS

Of our cohort of 150 patients, 62 (41%) were infected and 88 (59%) were not infected. Of the infected patients, 45% died or underwent transplantation, compared to 22% for the non-infected patients (P = 0.003). Univariate and multivariate analyses demonstrated that infections in patients with acute liver dysfunction were an independent predictor of poor outcome (i.e. death or transplantation). In addition, specific types of infection, including pneumonia, independently led to a 48% increase in length of stay (P = 0.002).

CONCLUSIONS

Infections in patients with acute liver dysfunction are associated with increased risk of death or transplant and increased hospital length of stay.

Role of inflammation and infection in the pathogenesis of human acute liver failure: Clinical implications for monitoring and therapy

Acute liver failure is a rare and devastating clinical condition. At present, emergency liver transplantation is the only life-saving therapy in advanced cases, yet the feasibility of transplantation is affected by the presence of systemic inflammation, infection and resultant multi-organ failure. The importance of immune dysregulation and acquisition of infection in the pathogenesis of acute liver failure and its associated complications is now recognised. In this review we discuss current thinking regarding the role of infection and inflammation in the pathogenesis of and outcome in human acute liver failure, the implications for the management of such patients and suggest directions for future research.

Acute Liver Failure: Diagnosis and Management

Acute liver failure is life threatening liver injury with coagulopathy and hepatic encephalopathy within 26 weeks and generally, in the absence of preexisting liver disease. Fulminant liver failure occurs when hepatic encephalopathy occurs within 8 weeks of jaundice. The majority of patients with ALF are women with the median age of 38 years. In the United States, drug induced liver injury including acetaminophen causes the majority of ALF cases. The etiology of ALF should be determined, if possible, because many causes have a specific treatment. The mainstay for ALF is supportive care and liver transplantation, if necessary. There are multiple prognostic criteria available. Prognosis can be poor and patients should be referred to a liver transplantation center as soon as possible.

Neutrophil Toll-Like Receptor 9 Expression and the Systemic Inflammatory Response in Acetaminophen-Induced Acute Liver Failure

OBJECTIVES

There is a marked propensity for patients with acetaminophen-induced acute liver failure to develop sepsis, which may culminate in multiple organ failure and death. Toll-like receptors sense pathogens and induce inflammatory responses, but whether this is protective or detrimental in acetaminophen-induced acute liver failure remains unknown.

DESIGN, SETTING, AND PATIENTS

We assessed Toll-like receptor expression on circulating neutrophils and their function in 24 patients with acetaminophen-induced acute liver failure and compared with 10 healthy controls.

INTERVENTIONS

Neutrophil Toll-like receptor 2, -4, and -9 expression and cytokine production and function were studied ex vivo at baseline and following stimulation with lipopolysaccharide, oligodeoxynucleotides, ammonium chloride, and interleukin-8. To examine the influence of acetaminophen-induced acute liver failure plasma and endogenous DNA on Toll-like receptors-9 expression, healthy neutrophils were incubated with acetaminophen-induced acute liver failure plasma with and without deoxyribonuclease-I.

MEASUREMENTS AND MAIN RESULTS

Circulating neutrophil Toll-like receptor 9 expression was increased in acetaminophen-induced acute liver failure on day 1 compared with healthy controls (p = 0.0002), whereas Toll-like receptor 4 expression was decreased compared with healthy controls (p < 0.0001). Toll-like receptor 2 expression was unchanged. Neutrophil phagocytic activity was decreased, and spontaneous oxidative burst increased in all patients with acetaminophen-induced acute liver failure compared with healthy controls (p < 0.0001). Neutrophil Toll-like receptor 9 expression correlated with plasma interleukin-8 and peak ammonia concentration (r = 0.6; p < 0.05) and increased with severity of hepatic encephalopathy (grade 0-2 vs 3/4) and systemic inflammatory response syndrome score (0-1 vs 2-4) (p < 0.05). Those patients with advanced hepatic encephalopathy (grade 3/4) or high systemic inflammatory response syndrome score (2-4) on day 1 had higher neutrophil Toll-like receptor 9 expression, arterial ammonia concentration, and plasma interleukin-8 associated with neutrophil exhaustion. Healthy neutrophil Toll-like receptor 9 expression increased upon stimulation with acetaminophen-induced acute liver failure plasma, which was abrogated by preincubation with deoxyribonuclease-I. Intracellular Toll-like receptor 9 was induced by costimulation with interleukin-8 and ammonia.

CONCLUSION

These data point to neutrophil Toll-like receptor 9 expression in acetaminophen-induced acute liver failure being mediated both by circulating endogenous DNA as well as ammonia and interleukin-8 in a synergistic manner inducing systemic inflammation, neutrophil exhaustion, and exacerbating hepatic encephalopathy.

Overview on acute-on-chronic liver failure

Liver failure (LF) is defined as severe dysfunction in hepatic synthesis, detoxification, and metabolism induced by various etiologies. Clinical presentation of LF typically includes severe jaundice, coagulation disorder, hepatic encephalopathy, and ascites. LF can be classified into acute LF, acute-on-chronic LF (ACLF), and chronic LF. ACLF has been demonstrated as a distinct syndrome with unique clinical presentation and outcomes. The severity, curability, and reversibility of ACLF have attracted considerable attention. Remarkable developments in ACLF-related conception, diagnostic criteria, pathogenesis, and therapy have been achieved. However, this disease, especially its diagnostic criteria, remains controversial. In this paper, we systemically reviewed the current understanding of ACLF from its definition, etiology, pathophysiology, pathology, and clinical presentation to management by thoroughly comparing important findings between east and west countries, as well as those from other regions. We also discussed the controversies, challenges, and needs for future studies to promote the standardization and optimization of the diagnosis and treatment for ACLF.

Analysis of infectious complications and timing for emergency liver transplantation in autoimmune acute liver failure

BACKGROUND

Autoimmune hepatitis (AIH) is one of major etiologies of acute liver failure (ALF), and the survival rate without liver transplantation (LT) of patients with fulminant AIH is especially poor worldwide. We investigated the clinicopathological features of infectious complications in autoimmune ALF retrospectively and tried to determine when to continue corticosteroid (CS) treatment or abandon it for LT.

METHODS

Twenty patients with autoimmune ALF, comprising five severe hepatitis, 13 fulminant hepatitis and two late onset hepatic failure, were analyzed.

RESULTS

Corticosteroids were administered to 19 patients. Seventeen infectious complications were observed in 12 patients. The median (range) duration between the introduction of CS and onset of infection was 15 (10–41) days. There were no significant differences in clinicobiochemical features between patients with and without infection. Of 20 patients, eight (40%) recovered without LT, four (20%) received LT and eight (40%) died without LT. Dead or transplanted patients had more advanced liver failure on admission than recovered ones (P < 0.01).

CONCLUSIONS

Two-week after the introduction of CS is a critical point for avoiding infectious complications. Therefore, we should have evaluated efficacy of CS and performed LT by then at the latest in case of failure to improve.