Liver histology as predictor of outcome in patients with acute liver failure

Liver histology and hepatic progenitor cell activity in pediatric acute liver failure: Implications for clinical outcome

BACKGROUND

Hepatic progenitor cell (HPC) activity and regenerative process that follows pediatric acute liver failure (PALF) is still not well understood. This clinicopathological study was thus conducted with an aim to study the correlation of liver histology and HPC activity with outcomes in PALF.

METHODS

All PALF patients with available hepatic histological specimens were included and specimens were analyzed for hepatocyte loss, HPC activity [using cytokeratin (CK) 7, CK19, sex-determining region Y-related high mobility group box(SOX)9 and epithelial cell adhesion molecule (EpCAM)], hepatocyte proliferation (using Ki67), and hepatocyte senescence (using p53 and p21).

RESULTS

Ninety-four children were included: 22 (23.4%) survived with native liver (SNL) (i.e., the good outcome group) while rest (i.e., the poor outcome group) either died [33%, 35.1%] or received liver transplant (LT) [39%, 41.5%]. When compared to subjects with poor outcomes, those in the SNL group exhibited significantly less severe hepatocyte loss, fewer HPC/hpf, more proliferating hepatocytes, and less senescent hepatocytes (p < .05). Increasing severity of hepatocyte loss (adjusted OR: 9.95, 95% CI: 4.22-23.45, p < .001) was identified as an independent predictor of poor outcome. Eighty percent children with >50% native hepatocyte loss had poor outcome within 10 days of hospitalization.

CONCLUSION

In PALF, more severe hepatocyte loss, higher number of HPC activation, lesser number of proliferating hepatocytes, and greater number of senescent hepatocytes are associated with a poor outcome. Loss of >50% hepatocytes is an independent predictor of poor outcome in PALF.

Management of Acute Liver Failure: Update 2022

Abbreviated pathogenesis and clinical course of the acute liver failure syndrome. The pathogenesis and clinical course of the syndrome of acute liver failure (ALF) differs depending upon the etiology of the primary liver injury. In turn, the severity of the liver injury and resulting synthetic failure is often the primary determinant of whether a patient is referred for emergency liver transplantation. Injuries by viral etiologies trigger the innate immune system via pathogen-associated molecular patterns (PAMPs), while toxin-induced (and presumably ischemia-induced) injuries do so via damage-associated molecular patterns (DAMPs). The course of the clinical syndrome further depends upon the relative intensity and composition of cytokine release, resulting in an early proinflammatory phenotype (SIRS) and later compensatory anti-inflammatory response phenotype (CARS). The outcomes of overwhelming immune activation are the systemic (extrahepatic) features of ALF (cardiovascular collapse, cerebral edema, acute kidney injury, respiratory failure, sepsis) which ultimately determine the likelihood of death.Acute liver failure (ALF) continues to carry a high risk of mortality or the need for transplantation despite recent improvements in overall outcomes over the past two decades. Optimal management begins with identifying that liver failure is indeed present and its etiology, since outcomes and the need for transplantation vary widely across the different etiologies. Most causes of ALF can be divided into hyperacute (ischemia and acetaminophen) and subacute types (other etiologies), based on time of evolution of signs and symptoms of liver failure; the former evolve in 3 to 4 days and the latter typically in 2 to 4 weeks. Both involve intense release of cytokines and hepatocellular contents into the circulation with multiorgan effects/consequences.Management involves optimizing fluid balance and cardiovascular support, including the use of continuous renal replacement therapy, vasopressors, and pulmonary ventilation. Early evaluation for liver transplantation is advised particularly for acetaminophen toxicity, which evolves so rapidly that delay is likely to lead to death.Vasopressor support, high-grade hepatic encephalopathy, and unfavorable (subacute) etiologies heighten the need for urgent listing for liver transplantation. Prognostic scores such as Kings Criteria, Model for End-Stage Liver Disease, and the Acute Liver Failure Group prognostic index take these features into account and provide reasonable but imperfect predictive accuracy. Future treatments may include liver support devices and/or agents that improve hepatocyte regeneration.

Safety, Feasibility, Yield, Diagnostic and Prognostic Implications of Transjugular Liver Biopsy in Children and Adolescents

OBJECTIVES

The objectives of the study were to evaluate the indications, feasibility, complications and clinical implications of transjugular liver biopsy (TJLB) in children.

METHODS

Data of all TJLB performed in children <18 years old was retrieved from the computerized hospital information system. TJLB was done using a 19 G quick-core needle biopsy system with 20 mm throw length. Hepatic venous pressure gradient was additionally measured in children with portal hypertension. A single pathologist reviewed all the biopsies again and provided structured information.

RESULTS

A total of 102 children, including 5 with acute liver failure underwent TJLB with technical success in 101 (99%). A mean of 2.3 ± 0.9 passes (range: 1-5) was taken for the biopsy. The most common indications for TJLB in our cohort were elevated international normalized ratio >1.5 (66, 64.7%), ascites (46, 45.1%) and thrombocytopenia (platelet count < 60,000/mm3) (42, 41.2%). Mean size of the tissue received was 14.5 ± 5.6 mm with an average of 10.2 ± 4.7 portal tracts. Only one child developed major (category D) complication (hemobilia) and 12 (11.8%) developed minor complications post-procedure. Etiological diagnosis could be made in a total of 64 (63.9%) children undergoing TJLB, the most common diagnosis being autoimmune hepatitis (n = 31), non-cirrhotic portal fibrosis (n = 16) and drug-induced liver injury (n = 4).

CONCLUSION

TJLB is well tolerated, feasible and helps make a diagnosis in close to 64% children allowing timely medical and/or surgical intervention. It is especially useful for diagnosis of autoimmune liver diseases, drug-induced liver injury and non-cirrhotic portal fibrosis.

Allograft Necrosis in Liver Biopsy Is Predictive for Organ Outcome and Patient Survival

AIM

To evaluate if any association existed between the extent of allograft necrosis in liver biopsy and patient survival.

METHODS

Sixty-nine patients who had 70 liver transplantations with allograft necrosis were included in the study. Correlations of necrosis, the Model for End-Stage Liver Disease (MELD) score, and allograft survival were analyzed.

RESULTS

Allograft failure rate within 1 month after index biopsy was worse in patients with a higher extent of necrosis (2.5%, 12.5%, 25%, and 40% in groups with allograft necrosis of 1-25%, 26-50%, 51-75%, and >75%, respectively). Adequate biopsy with more than 50% necrosis is associated with significant allograft failure (P <.001). The MELD scores did not always accurately predict fatality that was caused by massive necrosis. In the absence of substantial clinical changes, repetition of allograft biopsy within a short period of time did not provide additional value. Among patients with more than 75% allograft necrosis, one who received an immediate second transplantation survived and 3 out of 9 patients who had not received those deceased within 1 month.

CONCLUSIONS

Allograft necrosis demonstrates strong predictive power in organ and patient survival. Additionally, biopsy-proven allograft necrosis unequivocally pinpoints ischemia as the direct cause of allograft failure, which facilitates clinical management. Immediate retransplantation is crucial for patients with substantial allograft necrosis.

Indian National Association for the Study of the Liver Consensus Statement on Acute Liver Failure (Part 1): Epidemiology, Pathogenesis, Presentation and Prognosis

Acute liver failure (ALF) is an infrequent, unpredictable, potentially fatal complication of acute liver injury (ALI) consequent to varied etiologies. Etiologies of ALF as reported in the literature have regional differences, which affects the clinical presentation and natural course. In this part of the consensus article designed to reflect the clinical practices in India, disease burden, epidemiology, clinical presentation, monitoring, and prognostication have been discussed. In India, viral hepatitis is the most frequent cause of ALF, with drug-induced hepatitis due to antituberculosis drugs being the second most frequent cause. The clinical presentation of ALF is characterized by jaundice, coagulopathy, and encephalopathy. It is important to differentiate ALF from other causes of liver failure, including acute on chronic liver failure, subacute liver failure, as well as certain tropical infections which can mimic this presentation. The disease often has a fulminant clinical course with high short-term mortality. Death is usually attributable to cerebral complications, infections, and resultant multiorgan failure. Timely liver transplantation (LT) can change the outcome, and hence, it is vital to provide intensive care to patients until LT can be arranged. It is equally important to assess prognosis to select patients who are suitable for LT. Several prognostic scores have been proposed, and their comparisons show that indigenously developed dynamic scores have an edge over scores described from the Western world. Management of ALF will be described in part 2 of this document.

Ledipasvir and Sofosbuvir for Acute Hepatitis C Virus Monoinfection Associated with a High Risk of Acute Liver Failure

A 72-year-old Japanese man was referred to our hospital with yellow discoloration of the sclera and liver dysfunction. He was diagnosed with acute hepatitis C virus (HCV) infection on the basis of HCV-RNA positivity and anti-HCV seroconversion. A transjugular liver biopsy confirmed submassive hepatic necrosis. Five days after admission, no flapping tremor was observed, and the prothrombin time-international normalized ratio (PT-INR) and total bilirubin level showed increases of 1.70 and 17.8 mg/dL, respectively. The Model for End-Stage Liver Disease score was determined to be 25, and the risk of acute liver failure (ALF) was estimated to be 48% according to the Japan Hepatic Encephalopathy Prediction Model. Considering that rapid HCV clearance and temporary suppression of the immune response would prevent ALF, we prescribed oral ledipasvir (LDV) 90 mg and sofosbuvir (SOF) 400 mg for 12 weeks and intravenously injected methylprednisolone 1 g for 3 days. His PT-INR promptly improved, although the total bilirubin level increased to 30.3 mg/dL. Plasma bilirubin absorption was performed three times, and the total bilirubin level gradually decreased. HCV-RNA was still detectable at six weeks after the start of LDV/SOF therapy and finally undetectable at eight weeks. There were no adverse events associated with LDV/SOF. The patient was discharged 73 days after admission. A sustained virological response was achieved at 12 and 24 weeks after treatment. The findings from this case suggest that LDV/SOF therapy can be a promising option for acute HCV monoinfection associated with a high risk of ALF.

Acute liver failure

Acute liver failure is a rare and severe consequence of abrupt hepatocyte injury, and can evolve over days or weeks to a lethal outcome. A variety of insults to liver cells result in a consistent pattern of rapid-onset elevation of aminotransferases, altered mentation, and disturbed coagulation. The absence of existing liver disease distinguishes acute liver failure from decompensated cirrhosis or acute-on-chronic liver failure. Causes of acute liver failure include paracetamol toxicity, hepatic ischaemia, viral and autoimmune hepatitis, and drug-induced liver injury from prescription drugs, and herbal and dietary supplements. Diagnosis requires careful review of medications taken, and serological testing for possible viral exposure. Because of its rarity, acute liver failure has not been studied in large, randomised trials, and most treatment recommendations represent expert opinion. Improvements in management have resulted in lower mortality, although liver transplantation, used in nearly 30% of patients with acute liver failure, still provides a life-saving alternative to medical management.

[Multiple organ manifestations of liver failure in acute small bowel obstruction]

Modern surgical and intensive care achievements did not result decrease of mortality in patients with acute small bowel obstruction (ASBO). Direct cause of mortality in ASBO patients is peritonitis followed by multiple organ failure syndrome including acute failure of liver, kidneys, lungs and other organs. Publications devoted to the problem of acute liver failure and its complicationsare reviewed in the article. Mechanisms of pathogenesis and clinical manifestations of multiple organ failure syndrome in patients with acute small bowel obstruction are analyzed.

Transjugular diagnostics in acute liver failure including measurements of hepatocentral venous biomarker gradients

AIM

Acute liver failure (ALF) is a syndrome of severe liver injury that may need urgent liver transplantation and is associated with significant risk of death. Early outcome prediction and further possibilities to increase accuracy of prognosis scores are important.

METHODS

We examined 30 patients with ALF, according to the novel criteria of the Intractable Hepato-Biliary Diseases Study Group, who underwent transjugular liver biopsy (TJLB) and investigated the relevance of histology for correct diagnosis and etiology. We assessed the suitability of necrosis (%), hepatic venous pressure gradients (HVPG), and hepatocentral venous gradients of serum biomarkers for outcome prediction. For this purpose, we calculated the difference of biomarker levels between hepatic vein (HV) and superior vena cava (SVC) blood samples.

RESULTS

Histology of TJLB specimens contributed to finding the etiology in 83%. Necrosis (%) and HVPGs were not significantly different between outcome groups. In gradient measurements, caspase 3/7 activity and total cytokeratin 18 (CK-18) (M65) had significant and relevant levels different from zero. Although they were not accurate for outcome prediction, differences between outcome groups were detected in caspase activation: levels of caspase 3/7 activity in the HV and caspase-cleaved CK-18 (M30) in the SVC were significantly higher in spontaneously recovered patients.

CONCLUSIONS

Our results underline the role of caspase activation in spontaneous recovery from ALF. Furthermore, the calculation of hepatocentral venous biomarker gradients could represent a new diagnostic tool whose clinical potential needs to be further investigated.

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.

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.

Noninvasive Imaging of Drug-Induced Liver Injury with 18F-DFA PET

Drug-induced liver failure is a significant indication for a liver transplant, and unexpected liver toxicity is a major reason that otherwise effective therapies are removed from the market. Various methods exist for monitoring liver injury but are often inadequate to predict liver failure. New diagnostic tools are needed. Methods: We evaluate in a preclinical model whether ¹⁸F-2-deoxy-2-fluoroarabinose (¹⁸F-DFA), a PET radiotracer that measures the ribose salvage pathway, can be used to monitor acetaminophen-induced liver injury and failure. Mice treated with vehicle, 100, 300, or 500 mg/kg acetaminophen for 7 or 21 h were imaged with ¹⁸F-FDG and ¹⁸F-DFA PET. Hepatic radiotracer accumulation was correlated to survival and percentage of nonnecrotic tissue in the liver. Mice treated with acetaminophen and vehicle or N-acetylcysteine were imaged with ¹⁸F-DFA PET. ¹⁸F-DFA accumulation was evaluated in human hepatocytes engrafted into the mouse liver. Results: We show that hepatic ¹⁸F-DFA accumulation is 49%-52% lower in mice treated with high-dose acetaminophen than in mice treated with low-dose acetaminophen or vehicle. Under these same conditions, hepatic ¹⁸F-FDG accumulation was unaffected. At 21 h after acetaminophen treatment, hepatic ¹⁸F-DFA accumulation can distinguish mice that will succumb to the liver injury from those that will survive it (6.2 vs. 9.7 signal to background, respectively). Hepatic ¹⁸F-DFA accumulation in this model provides a tomographic representation of hepatocyte density in the liver, with a R² between hepatic ¹⁸F-DFA accumulation and percentage of nonnecrotic tissue of 0.70. PET imaging with ¹⁸F-DFA can be used to distinguish effective from ineffective resolution of acetaminophen-induced liver injury with N-acetylcysteine (15.6 vs. 6.2 signal to background, respectively). Human hepatocytes, in culture or engrafted into a mouse liver, have levels of ribose salvage activity similar to those of mouse hepatocytes. Conclusion: Our findings suggest that PET imaging with ¹⁸F-DFA can be used to visualize and quantify drug-induced acute liver injury and may provide information on the progression from liver injury to hepatic failure.

Substantial hepatic necrosis is prognostic in fulminant liver failure

AIM

To evaluate if any association existed between the extent of hepatic necrosis in initial liver biopsies and patient survival.

METHODS

Thirty-seven patients with fulminant liver failure, whose liver biopsy exhibited substantial necrosis, were identified and included in the study. The histological and clinical data was then analyzed in order to assess the relationship between the extent of necrosis and patient survival, with and without liver transplantation. The patients were grouped based on the etiology of hepatic necrosis. Each of the etiology groups were then further stratified according to whether or not they had received a liver transplant post-index biopsy, and whether or not the patient survived.

RESULTS

The core tissue length ranged from 5 to 44 mm with an average of 23 mm. Causes of necrosis included 14 autoimmune hepatitis, 10 drug induced liver injury (DILI), 9 hepatitis virus infection, and 4 unknown origin. Among them, 11 showed submassive (26%-75% of the parenchymal volume) and 26 massive (76%-100%) necrosis. Transplant-free survival was worse in patients with a higher extent of necrosis (40%, 71.4% and 100% in groups with necrosis of 76%-100%, 51%-75% and 26%-50%, respectively). Additionally, transplant-free survival rates were 66.7%, 57.1%, and 25.0% in groups of autoimmune hepatitis, DILI, and viral hepatitis, respectively. Even after liver transplantation, the survival rate in patients as a result of viral hepatitis remained the lowest (80%, 100%, and 40% in groups of autoimmune hepatitis, DILI, and viral hepatitis, respectively).

CONCLUSION

Adequate liver biopsy with more than 75% necrosis is associated with significant transplant-free mortality that is critical in predicting survival.

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.

Pediatric acute liver failure of undetermined cause: A research workshop

Pediatric acute liver failure (PALF) is a potentially devastating condition that occurs in previously healthy children of all ages and frequently leads to a rapid clinical deterioration. An identified cause for liver injury is lacking in approximately 30% of cases. Children with undetermined diagnosis have lower spontaneous survival and higher rates of transplantation and death than other diagnostic groups. A single-day workshop sponsored by the National Institute of Diabetes and Digestive and Kidney Diseases brought together clinicians and basic scientists to integrate aligned research findings and develop a foundation for new mechanistic studies and future treatment trials. The clinical phenotype of indeterminate PALF shares important similarities to the hyperinflammatory state characteristic of hemophagocytic lymphohistiocytosis (HLH) and macrophage activation syndrome (MAS). A failure of cytotoxic T cells to limit or contract inflammatory responses may propagate injury and lead to a local and systemic milieu that does not support normal hepatic regeneration. Evidence was presented that bone marrow (BM)-derived Sinusoidal endothelial cell PROgenitor Cells (sprocs) play a vital role in hepatic regeneration. Overwhelming systemic inflammatory responses may suppress mobilization of BM sprocs and dampen hepatic recovery.

CONCLUSION

Experience gained through treatment trials of HLH and MAS in childhood may inform study design for therapy of PALF. Successful approaches to limiting neuroinflammation through reduction of systemic inflammation and standardized neuroprotection protocols that limit glial injury could significantly improve intact survival. Finally, given that PALF is a rare disease, investigative efforts must include broad multicenter collaboration and careful stewardship of biorepository specimens. (Hepatology 2017;65:1026-1037).

Acute liver failure in Chinese children: a multicenter investigation

BACKGROUND

Currently, no documentation is available regarding Chinese children with acute liver failure (ALF). This study was undertaken to investigate etiologies and outcomes of Chinese children with ALF.

METHODS

We retrospectively enrolled 32 pediatric patients with ALF admitted in five hospitals in different areas of China from January 2007 to December 2012. The coagulation indices, serum creatinine, serum lactate dehydrogenase, blood ammonia and prothrombin activity were analyzed; the relationship between these indices and mortality was evaluated by multivariate analysis.

RESULTS

The most common causes of Chinese children with ALF were indeterminate etiology (15/32), drug toxicity (8/32), and acute cytomegalovirus hepatitis (6/32). Only 1 patient (3.13%) received liver transplantation and the spontaneous mortality of Chinese children with ALF was 58.06% (18/31). Patients who eventually died had higher baseline levels of international normalized ratio (P=0.01), serum creatinine (P=0.04), serum lactate dehydrogenase (P=0.01), blood ammonia (P<0.01) and lower prothrombin activity (P=0.01) than those who survived. Multivariate analysis showed that the entry blood ammonia was the only independent factor significantly associated with mortality (odds ratio=1.069, 95% confidence interval 1.023-1.117, P<0.01) and it had a sensitivity of 94.74%, a specificity of 84.62% and an accuracy of 90.63% for predicting the death. Based on the established model, with an increase of blood ammonia level, the risk of mortality would increase by 6.9%.

CONCLUSIONS

The indeterminate causes predominated in the etiologies of ALF in Chinese children. The spontaneous mortality of pediatric patients with ALF was high, whereas the proportion of patients undergoing liver transplantation was significantly low. Entry blood ammonia was a reliable predictor for the death of pediatric patients with ALF.

Causes and outcomes of acute liver failure in China

Objectives

No extensive investigation has been performed and thus no representative data are available regarding acute liver failure (ALF) in China. This study aims to investigate the causes and outcomes of ALF in China and establish a prognostic model.

Methods

Patients diagnosed as ALF in seven hospitals in different areas of China from January 2007 to December 2012 were retrospectively selected.

Results

Of the 177 patients included in this study, 112 (63.28%) eventually died. The common causes of ALF were drug toxicity (43.50%), indeterminate etiology (29.38%) and acute viral hepatitis (11.30%). Additionally, traditional Chinese herbs predominated in the causes of drug-induced ALF (30/77). No patients in this study received liver transplantation. In the established model for predicting death in ALF, four variables were finally selected out, including age (P=0.01), the entry hepatic encephalopathy grade (P=0.04), international normalized ratio (P<0.01) and arterial blood ammonia (P=0.02). Using a threshold value of 0.5683, this model had a sensitivity of 95.24% and a specificity of 91.30%.

Conclusions

Traditional Chinese medicine was a major cause of ALF in China. The spontaneous mortality of ALF was high, whereas the rate of liver transplantation was significantly low. The established prognostic model of ALF had superior sensitivity and specificity.