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.

The Value of Electroencephalogram (EEG) Findings in the Evaluation and Treatment Management of Pediatric Acute Liver Failure

Background Pediatric acute liver failure (PALF) is still life-threatening and requires urgent care. The presence of encephalopathy is a clinical diagnosis, but it is more difficult to diagnose in children than in adults, and an electroencephalogram (EEG) can be invaluable. The role of EEG in managing the treatment of patients with PALF, other than the identification of encephalopathy, is unknown. This study aimed to investigate patients' EEGs, which may guide in choosing the most appropriate treatment in encephalopathy children. A further aim was to investigate a new score method, based on the laboratory results, which might indicate the presence of encephalopathy in cases with PALF. Methods Medical data of 33 PALF patients followed in our clinic were reviewed retrospectively. This study included 33 patients, whose EEG recording was taken on the first day of supportive treatment due to liver failure in the pediatric intensive care unit (PICU). The EEG findings were categorized into three classes: normal, epileptic and non-epileptic paroxysmal, and background encephalopathic patterns including widespread slowing and voltage suppression. Result This retrospective study included 13 male and 20 female patients with a mean age at presentation of 4.82±4.81 months whose EEG was performed on the first day of supportive therapy for liver failure in the PICU. The EEG findings were categorized into three groups: normal, epileptic and non-epileptic paroxysms, and encephalopathic patterns including diffuse background slowing and voltage suppression. Comparing EEG findings and treatments, we found that the normal EEG group responded well to liver-supporting therapy and the rate of plasmapheresis treatment was significantly higher in the diffuse slowing group. Patients with diffuse slowing of the EEG were 9.6 times more likely to receive plasmapheresis. We found that above a cut-off of ≥7.5 for the TAI (total bilirubin, albumin, and international normalized ratio (INR)) score used in our study, the risk of developing encephalopathy increased 14.4-fold. Conclusions In PALF, EEG findings can provide findings that will help clinicians in determining treatment selection and prognosis, as well as detecting epileptic focus and encephalopathy. The TAI score can be used to assess the risk of encephalopathy in cases of PALF, when it is challenging to identify encephalopathy or when an EEG is not possible.

Disorders of vesicular trafficking presenting with recurrent acute liver failure: NBAS, RINT1, and SCYL1 deficiency

Among genetic disorders of vesicular trafficking, there are three causing recurrent acute liver failure (RALF): NBAS, RINT1, and SCYL1-associated disease. These three disorders are characterized by liver crises triggered by febrile infections and account for a relevant proportion of RALF causes. While the frequency and severity of liver crises in NBAS and RINT1-associated disease decrease with age, patients with SCYL1 variants present with a progressive, cholestatic course. In all three diseases, there is a multisystemic, partially overlapping phenotype with variable expression, including liver, skeletal, and nervous systems, all organ systems with high secretory activity. There are no specific biomarkers for these diseases, and whole exome sequencing should be performed in patients with RALF of unknown etiology. NBAS, SCYL1, and RINT1 are involved in antegrade and retrograde vesicular trafficking. Pathomechanisms remain unclarified, but there is evidence of a decrease in concentration and stability of the protein primarily affected by the respective gene defect and its interaction partners, potentially causing impairment of vesicular transport. The impairment of protein secretion by compromised antegrade transport provides a possible explanation for different organ manifestations such as bone alteration due to lack of collagens or diabetes mellitus when insulin secretion is affected. Dysfunction of retrograde transport impairs membrane recycling and autophagy. The impairment of vesicular trafficking results in increased endoplasmic reticulum stress, which, in hepatocytes, can progress to hepatocytolysis. While there is no curative therapy, an early and consequent implementation of an emergency protocol seems crucial for optimal therapeutic management.

Combined Therapeutic Plasma Exchange and Continuous Renal Replacement Therapy in Children With Dengue-Associated Acute Liver Failure and Shock Syndrome: Single-Center Cohort From Vietnam

OBJECTIVES

Pediatric acute liver failure (PALF) is a fatal complication in patients with severe dengue. To date, clinical data on the combination of therapeutic plasma exchange (TPE) and continuous renal replacement therapy (CRRT) for managing dengue-associated PALF concomitant with shock syndrome are limited.

DESIGN

Retrospective cohort study (January 2013 to June 2022).

PATIENTS

Thirty-four children.

SETTING

PICU of tertiary Children's Hospital No. 2 in Vietnam.

INTERVENTIONS

We assessed a before-versus-after practice change at our center of using combined TPE and CRRT (2018 to 2022) versus CRRT alone (2013 to 2017) in managing children with dengue-associated acute liver failure and shock syndrome. Clinical and laboratory data were reviewed from PICU admission, before and 24 h after CRRT and TPE treatments. The main study outcomes were 28-day in-hospital mortality, hemodynamics, clinical hepatoencephalopathy, and liver function normalization.

MEASUREMENTS AND MAIN RESULTS

A total of 34 children with a median age of 10 years (interquartile range: 7-11 yr) underwent standard-volume TPE and/or CRRT treatments. Combined TPE and CRRT ( n = 19), versus CRRT alone ( n = 15), was associated with lower proportion of mortality 7 of 19 (37%) versus 13 of 15 (87%), difference 50% (95% CI, 22-78; p < 0.01). Use of combined TPE and CRRT was associated with substantial advancements in clinical hepatoencephalopathy, liver transaminases, coagulation profiles, and blood lactate and ammonia levels (all p values < 0.001).

CONCLUSIONS

In our experience of children with dengue-associated PALF and shock syndrome, combined use of TPE and CRRT, versus CRRT alone, is associated with better outcomes. Such combination intervention was associated with normalization of liver function, neurological status, and biochemistry. In our center we continue to use combined TPE and CRRT rather than CRRT alone.

Rapid Genome Sequencing Diagnosis in Pediatric Patients with Liver Dysfunction

OBJECTIVE

To describe the usefulness of rapid whole genome sequencing (rWGS) in a cohort of children presenting with acute liver dysfunction.

STUDY DESIGN

This was a retrospective, population-based cohort study conducted at Primary Children's Hospital in Salt Lake City, Utah. Children meeting criteria for acute liver dysfunction who received rWGS between August 2019 and December 2021 were included. rWGS was performed on blood samples from the patient and parents (1 or both depending on availability). The clinical characteristics of patients with positive rWGS results were compared with those with negative results.

RESULTS

Eighteen patients with pediatric acute liver dysfunction who had rWGS were identified. The median turnaround time from the date rWGS testing was ordered to the date an initial report was received was 8 days with a shorter turnaround time in patients with a diagnostic rWGS (4 days vs 10 days; P = .03). A diagnostic result was identified in 7 of 18 patients (39%). Subsequently, 4 patients in this cohort, who had negative rWGS results, were found to have a toxic exposure accounting for their liver dysfunction. With removal of these patients, the diagnostic rate of rWGS was 7 of 14 (50%). The use of rWGS led to a change in management for 6 of 18 patients (33%).

CONCLUSIONS

We found that rWGS provided a diagnosis in up to 50% of pediatric acute liver dysfunction. rWGS allows for higher diagnostic rates in an expedited fashion that affects clinical management. These data support the routine use of rWGS for life-threatening disorders in children, specifically acute liver dysfunction.

Severe Acute Hepatitis of Unknown Etiology Presenting as Pediatric Acute Liver Failure: Analysis of Likely Etiology, Clinical Course and Outcome

Adenovirus, adeno-associated virus, and severe acute respiratory syndrome-coronavirus-2 (SARS-COV2) have been recently implicated as probable causative agents of severe acute hepatitis of unknown etiology reported from most of Europe. High mortality and liver transplantation (LT) rates have been observed in those presenting with acute liver failure (ALF). Such cases have not been reported from the Indian subcontinent. We analyzed the etiologies, clinical course, and in-hospital outcomes of cases of severe acute hepatitis with ALF presenting to us between May and October 2022. A total of 178 children presented with severe acute hepatitis of known/unknown etiology including 28 presenting as ALF. Eight of them fulfilled the definition of severe acute hepatitis of unknown etiology presenting as ALF. Adenovirus was not associated with cases of ALF in these children. SARS-COV2 antibodies were detected in 6 (75%) of them. Children with severe acute hepatitis of unknown etiology presenting as ALF were young (median age 4 years), had hyper-acute presentation with a predominance of gastrointestinal symptoms, and a fulminant course with worse outcomes (native liver survival 25%). Expedited evaluation of these children for LT would be the key to management.

RNA-Sequencing Analysis Identifies Etiology Specific Transcriptional Signatures in Neonatal Acute Liver Failure

OBJECTIVE

To assess hepatic transcriptional signatures in infants with gestational alloimmune liver disease (GALD) compared with other etiologies of neonatal acute liver failure (ALF) and older pediatric patients with ALF.

STUDY DESIGN

Neonates with ALF (international normalized ratio ≥2 within 30 days of life) and deceased neonates without liver disease (<30 days of age) with available liver tissue between 2010 and 2021 were identified at Ann & Robert H. Lurie Children's Hospital of Chicago. Clinical information, liver histology, and data from RNA-sequencing analysis was compared between neonates with GALD, non-GALD etiologies of neonatal ALF, and nondiseased neonatal liver.

RESULTS

Quantification of trichrome staining showed an increase in fibrosis in patients with GALD vs those with non-GALD neonatal ALF (P = .012); however, quantification of α-cytokeratin 19-positive ductules did not differ between groups (P = .244). Gene set enrichment analysis of RNA-sequencing data identified the pathways of complement activation, fibrosis, and organogenesis to be upregulated in patients with GALD with ALF. In contrast, patients with non-GALD causes of neonatal ALF had increased gene expression for interferon-driven immune pathways. Individual genes upregulated in GALD included matrix metallopeptidase 7, hepatocyte growth factor, and chemokine ligand 14.

CONCLUSIONS

We have identified distinct pathways that are significantly upregulated in patients with GALD and potential disease-specific diagnostic biomarkers. Future studies will aim to validate these findings and help identify GALD-specific diagnostic biomarkers to improve diagnostic accuracy and reduce GALD-associated patient mortality.

Severe Acute Hepatitis: An Emerging Grave Illness in Children

Acute hepatitis of unknown origin in children has been recently described in the literature, and a case definition has also been proposed for this condition. The exact etiology is unknown and exclusion of infectious, metabolic, autoimmune and toxin mediated injuries is essential. Management for this condition is supportive, but some may require liver transplantation. Infection prevention and control practices are important as the etiology remains unidentified.

High Prevalence of Hemophagocytic Lymphohistiocytosis in Acute Liver Failure of Infancy

OBJECTIVES

To investigate the prevalence of hemophagocytic lymphohistiocytosis (HLH) syndrome in pediatric acute liver failure (PALF) of infancy and assess the diagnostic role of rapid immunologic tests, genotype/phenotype correlations, and clinical outcomes.

STUDY DESIGN

We retrospectively analyzed 78 children with PALF aged <24 months referred over almost 2 decades. The studied patients with a phenotype of HLH syndrome had a comprehensive immunologic workup, including additional genetic analysis for primary immunologic causes.

RESULTS

Thirty of the 78 children had the HLH phenotype and underwent genetic assessment, which demonstrated positive findings in 19 (63.3%), including 9 (30%) with biallelic primary HLH mutations and 10 (33.3%) with heterozygous mutations and/or polymorphisms. The most common form of primary HLH was familial hemophagocytic lymphohistiocytosis (FHL)-2, diagnosed in 6 children, 4 of whom had a c.50delT (p.Leu17ArgfsTer34) mutation in the PRF1 gene. Three patients with primary HLH received genetic diagnoses of FHL-3, Griscelli syndrome, and LRBA (lipopolysaccharide-responsive vesicle trafficking, beach- and anchor-containing) protein deficiency. Overall mortality in the series was 52.6% (10 of 19), and mortality in children with a documented biallelic pathogenic HLH mutation (ie, primary HLH) was 66.6% (6 of 9). Two children underwent liver transplantation, and 4 children underwent emergency hematopoietic stem cell transplantation; all but 1 child survived medium term.

CONCLUSIONS

Primary HLH can be diagnosed retrospectively in approximately one-third of infants with indeterminate PALF (iPALF) who meet the clinical criteria for HLH, often leading to their death. The most common HLH type in iPALF is FHL-2, caused by biallelic mutations in PRF-1. The clinical relevance of observed heterozygous mutations and variants of uncertain significance requires further investigation. Prompt hematopoietic stem cell transplantation could be life-saving in infants who survive the liver injury.

Pediatric Acute Liver Failure: A Clinicopathological Perspective

Pediatric acute liver failure (PALF) is a life-threatening disorder characterized by acute hepatocellular injury occurring in children without recognized underlying liver disease. The clinicopathologic evaluation of PALF requires a different approach from that in adults. The diagnostic considerations differ depending on the age, personal and family history, geographical region, and clinical presentation. Distinct entities such as gestational alloimmune liver disease, herpes simplex virus infection, and metabolic disorders should be considered in neonates with acute liver failure, while acetaminophen toxicity and autoimmune hepatitis are more frequently seen in older children and adolescents. An identified cause for PALF despite a negative complete evaluation (indeterminate) is lacking in 30 to 50% of cases. Although not routinely performed in the setting of PALF, liver biopsy may be helpful in assessing the etiology, potential mechanisms of injury, determining the appropriateness of liver transplantation, and prognostication of the patients. In this article, we review the clinicopathologic characteristics of PALF with an emphasis on general approach of pathologic evaluation and histopathologic characteristic of selected entities.

Outcomes Analyses of Pediatric Acute Liver Failure Subjects Listed for Liver Transplantation

BACKGROUND

We characterized recent outcomes in US pediatric acute liver failure (PALF) subjects listed for liver transplantation (LT) using the Scientific Registry of Transplant Recipients (SRTR) database.

METHODS

Pediatric subjects listed for LT from 2002 to 2015 were assigned to the "PALF" group based on status 1/1A listing, INR >2, no hepatic artery thrombosis, and no primary graft nonfunction (N = 397). Subjects were assigned to the "non-PALF" group if listed with any status other than 1/1A (N = 4509).

RESULTS

The PALF group had more infants <3 months of age and males at listing for LT compared to the non-PALF group. Two-thirds of PALF subjects had an indeterminate etiology. LT waitlist survival was significantly worse in the PALF group compared to the non-PALF group. Likelihood of removal from the LT waitlist for being "too sick" was higher, while that of removal for "spontaneous recovery" was lower in PALF subjects. Post-LT short-term (30 days) and long-term (60 months) outcomes were also significantly worse in PALF versus non-PALF subjects. PALF subjects who underwent living-donor-liver-transplant (LDLT) had similar LT waitlist times and post-LT survival compared to those undergoing deceased-donor-liver-transplant (DDLT). Over the study period, we observed a decreased number of liver transplants, and increase in LT waitlist- and short-term post-LT-survival in PALF subjects.

CONCLUSION

LT waitlist and post-LT outcomes are worse in PALF subjects compared to non-PALF subjects. PALF subjects who undergo LDLT have similar waitlist times and post-LT outcomes compared to those undergoing DDLT.

Association of duration and etiology with the effect of the artificial liver support system in pediatric acute liver failure

BACKGROUND

We aimed to assess the efficacy of the artificial liver support system (ALSS) in pediatric acute liver failure (PALF) patients and to examine the risk factors associated with the effect of ALSS. Similar data are limited in PALF.

METHODS

All patients diagnosed with PALF who received ALSS from June 2011 to June 2021 in the pediatric intensive care unit of the First Hospital of Jilin University were included in this retrospective cohort analysis. The effect of ALSS was measured using difference tests before and after treatments. The risk factors associated with the effect of ALSS were evaluated according to whether the total bilirubin (TBIL) and serum ammonia decreased after ALSS (TBIL-unresponsive group vs. TBIL-responsive group, serum ammonia-unresponsive group vs. serum ammonia-responsive group).

RESULTS

Thirty-nine patients who received ALSS during the study period were eligible for inclusion. The most common cause of PALF was undetermined causes (n = 14, 35.9%) followed by infection (n = 11, 28.2%). Four patients received pediatric liver transplantation. The overall survival rate was 76.9% (30/39). Fifteen (38.4%) patients received only one modality, whereas 61.6% patients received hybrid treatments. The most commonly used modality of ALSS was plasma exchange combined with continuous renal replacement therapy (n = 14, 35.9%). Alanine aminotransferase, TBIL, the international normalized ratio, and serum ammonia were significantly decreased after ALSS (P < 0.001). Compared with other causes, more patients with infection and toxication were observed in the TBIL-unresponsive group. A longer ALSS duration was significantly related to blood ammonia reduction.

CONCLUSIONS

ALSS can effectively reduce serum alanine aminotransferase, TBIL, international normalized ratio, and serum ammonia and may reduce mortality. The reduction in TBIL levels after ALSS is dependent on etiology. A longer ALSS duration was associated with blood ammonia reduction. Prospective multicenter studies are needed for further validation.

Pediatric acute liver failure: An experience of a pediatric intensive care unit from resource limited settings

INTRODUCTION

Pediatric acute liver failure is a rare and serious disease. Though liver transplantation is considered as the established treatment option for patients who are unlikely to recover with medical management, however, with the advancement of medical care there has been an increase in spontaneous regeneration of liver, obviating the need for liver transplantation. We identified the etiologies, outcome and prognostic factors of acute liver failure and the validity of the existing liver transplantation criteria to predict the outcome of pediatric acute liver failure.

MATERIALS AND METHODS

This was a retrospective study done from January 2014 to December 2019 in a tertiary pediatric critical care unit in South India. All children aged between 1 month to 18 years admitted with acute liver failure were enrolled.

RESULTS

Of 125 children with acute liver failure, the main etiologies were infections (32%), indeterminate (23%), paracetamol toxicity (21%), metabolic (13%) and others (11%). Dengue was the most common infection (55%). The median pediatric logistic organ dysfunction score at admission was 12 (4-27). Of 125 patients, 63.2% (n = 79) had spontaneous regeneration which was higher in paracetamol induced (92.3%) compared to non-paracetamol induced acute liver failure (55.5%). Only two patients underwent liver transplantation and 35% died. Peak alanine transaminase and use of inotropes significantly predicted the outcome of disease. Of 38 children meeting King's College Hospital criteria for liver transplantation, 57.9% had spontaneous regeneration and 36.8% died. Of 74 children meeting INR > 4 criteria, 54% (n = 40) had spontaneous regeneration and 43.2% died. INR >4 criteria was more sensitive than King's College Hospital criteria for predicting the need for liver transplantation.

CONCLUSION

Pediatric acute liver failure is caused by varied etiologies and infections were the commonest cause. Despite having a seriously ill cohort of patients, medical management resulted in spontaneous regeneration in the majority of children with acute liver failure. The use of inotropes, advanced hepatic encephalopathy, and peak alanine transaminase were predictors of poor outcome in children with acute liver failure and these patients could be considered for liver transplantation as available. Therefore, we may need to develop better predictors of pediatric acute liver failure in resource limited settings.

Hepatic Encephalopathy in Children With Acute Liver Failure: Utility of Serum Neuromarkers

BACKGROUND

Pediatric acute liver failure (PALF) is a public heath burden, often requiring prolonged hospitalization and liver transplantation. Hepatic encephalopathy (HE) is a complication of PALF with limited diagnostic tools to predict outcomes. Serum neurological markers (neuron-specific enolase, S100β, and myelin basic protein) can be elevated in traumatic or ischemic brain injury. We hypothesized that these neuromarkers would be associated with the development of HE in PALF.

METHODS

PALF study participants enrolled between May 2012 and December 2014 by 12 participating centers were the subjects of this analysis. Daily HE assessments were determined by study investigators. Neurological and inflammatory markers were measured using enzyme-linked immunosorbent assay and MILLIPLEX techniques, respectively. To model encephalopathy, these markers were log2 transformed and individually examined for association with HE using a generalized linear mixed model with a logit link and random intercept.

RESULTS

Eighty-two children had neurological and inflammatory marker levels and HE assessments recorded, with the majority having assessments for 3 days during their illness. An indeterminate diagnosis (29%) was most common and the median age was 2.9 years. Significant associations were observed for HE with S100β (odds ratio 1.16, 95% confidence interval [1.03-1.29], P = 0.04) and IL-6 (odds ratio 1.24 [1.11-1.38], P = 0.006).

CONCLUSIONS

Serum S100β and IL-6 are associated with HE in children with PALF. Measuring these markers may assist in assessing neurological injury in PALF, impacting clinical decisions.

Pediatric liver failure: we came, we saw, but have we conquered?

Although there have been advances made in the diagnosis and management of pediatric acute liver failure, there is still no consensus regarding the definition or standardized evaluation, and an inability to predict outcomes, specifically irreversible brain injury, in many patients exists. Much of the research surrounding pediatric acute liver failure in the last several years has centered on the development of predictive scoring systems to enhance diagnosis and treatment decisions. In this article, we will discuss our current understanding of liver failure and updated management strategies in children with acute liver failure.