Biliary atresia and other cholestatic childhood diseases: Advances and future challenges

Comparison of the outcomes of biliary atresia with cystic degeneration and isolated biliary atresia: A matched-pair analysis

BACKGROUND

Patients with biliary atresia (BA) with extrahepatic cystic degeneration (BACD) have a unique pathophysiology; however, clinical outcomes and progression of perinatal degeneration are not well-defined. We aimed to investigate the differences in clinical characteristics and outcomes between BACD and isolated BA (IBA).

METHODS

We performed a retrospective analysis of patients with BA who underwent Kasai portoenterostomy (KPE) from August 1997 to January 2018 and compared the clinical features and outcomes between BACD (n = 21) and IBA (n = 237). Matched-pair analysis for age and sex was performed between BACD and IBA groups to reduce confounding.

RESULTS

Before matched-pair analysis, we found that BACD patients were younger at KPE (45 vs. 64 days, p = 0.008), showed lower total bilirubin at the 3-month follow-up (0.5 vs. 1.4 mg/dL, p = 0.002), and higher 5-year native liver survival rate (95.2% vs. 61.4%, p = 0.006) than IBA patients. After matching, the BACD group showed significantly lower total bilirubin levels at the 3-month follow-up (0.5 vs. 1.5 mg/dL, p = 0.036) and higher 5-year native liver survival rate (95.2% vs. 57.5%, p = 0.006) than the IBA group.

CONCLUSION

BACD demonstrated higher bilirubin clearance and native liver survival rates than IBA.

LEVELS OF EVIDENCE

Treatment Study, Level III.

The relative abundance of monocyte subsets determines susceptibility to perinatal hepatic inflammation

The devastating consequences of perinatal liver inflammation contribute to a pressing need to develop therapeutics for the diseases that underly this condition. Biliary atresia (BA) is a perinatal inflammatory disease of the liver that results in obliterative cholangiopathy and rapidly progresses to liver failure, requiring transplantation. The ability to develop targeted therapies requires an understanding of the immune mechanisms that mitigate perinatal liver inflammation. This article reviews our recent findings demonstrating that in a murine model of perinatal hepatic inflammation, Ly6c^Lo non-classical monocytes express a pro-reparative transcriptomic profile and that the relative abundance of Ly6c^Lo monocytes promotes resolution of perinatal liver inflammation, rendering neonatal pups resistant to disease. We also examine the lineage relationship between monocyte subsets, reviewing data that suggests classical monocytes are a precursor for non-classical monocytes, and the alternative possibility that separate progenitors exist for each subset. Although a precursor-product relationship between classical and non-classical monocytes might exist in certain environments, we argue that they may also arise from separate progenitors, which is evident by sustained Ly6c^Lo non-classical monocyte expansion when Ly6c^Hi monocytes are absent. An improved understanding of monocyte subsets and their developmental trajectories during perinatal hepatic inflammation will provide insight into how therapies directed at controlling monocyte function may help alleviate the devastating consequences of diseases like BA.

Potential of ileal bile acid transporter inhibition as a therapeutic target in Alagille syndrome and progressive familial intrahepatic cholestasis

Alagille syndrome (ALGS) and progressive familial intrahepatic cholestasis (PFIC) are rare, inherited cholestatic liver disorders that manifest in infants and children and are associated with impaired bile flow (ie cholestasis), pruritus and potentially fatal liver disease. There are no effective or approved pharmacologic treatments for these diseases (standard medical treatments are supportive only), and new, noninvasive options would be valuable. Typically, bile acids undergo biliary secretion and intestinal reabsorption (ie enterohepatic circulation). However, in these diseases, disrupted secretion of bile acids leads to their accumulation in the liver, which is thought to underlie pruritus and liver-damaging inflammation. One approach to reducing pathologic bile acid accumulation in the body is surgical biliary diversion, which interrupts the enterohepatic circulation (eg by diverting bile acids to an external stoma). These procedures can normalize serum bile acids, reduce pruritus and liver injury and improve quality of life. A novel, nonsurgical approach to interrupting the enterohepatic circulation is inhibition of the ileal bile acid transporter (IBAT), a key molecule in the enterohepatic circulation that reabsorbs bile acids from the intestine. IBAT inhibition has been shown to reduce serum bile acids and pruritus in trials of paediatric cholestatic liver diseases. This review explores the rationale of inhibition of the IBAT as a therapeutic target, describes IBAT inhibitors in development and summarizes the current data on interrupting the enterohepatic circulation as treatment for cholestatic liver diseases including ALGS and PFIC.

Recent developments in diagnostics and treatment of neonatal cholestasis

Neonatal cholestasis is characterized by conjugated hyperbilirubinemia in the newborn and young infant and is a sign common to over 100 hepatobiliary and/or metabolic disorders. A timely evaluation for its etiology is critical in order to quickly identify treatable causes such as biliary atresia, many of which benefit from early therapy. An expanding group of molecularly defined disorders involving bile formation, canalicular transporters, tight junction proteins and inborn errors of metabolism are being continuously discovered because of advances in genetic testing and bioinformatics. The advent of next generation sequencing has transformed our ability to test for multiple genes and whole exome or whole genome sequencing within days to weeks, enabling rapid and affordable molecular diagnosis for disorders that cannot be directly diagnosed from standard blood tests or liver biopsy. Thus, our diagnostic algorithms for neonatal cholestasis are undergoing transformation, moving genetic sequencing to earlier in the evaluation pathway once biliary atresia, "red flag" disorders and treatable disorders are excluded. Current therapies focus on promoting bile flow, reducing pruritus, ensuring optimal nutrition, and monitoring for complications, without addressing the underlying cause of cholestasis in most instances. Our improved understanding of bile formation and the enterohepatic circulation of bile acids has led to emerging therapies for cholestasis which require appropriate pediatric clinical trials. Despite these advances, the cause and optimal therapy for biliary atresia remain elusive. The goals of this review are to outline the etiologies, diagnostic pathways and current and emerging management strategies for neonatal cholestasis.

Ileal bile acid transporter inhibition as an anticholestatic therapeutic target in biliary atresia and other cholestatic disorders

Biliary atresia is a rare cholestatic liver disease that presents in infants and rapidly advances to death in the absence of intervention. As a result of blockage or destruction of the biliary tract, bile acids accumulate and drive inflammation, fibrosis, and disease progression. The standard of care, Kasai portoenterostomy (KPE), is typically performed shortly after diagnosis (currently at ~ 2 months of age) and aims to restore bile flow and relieve cholestasis. Nevertheless, most patients continue to experience liver injury from accumulation of bile acids after KPE, since there are no known effective therapeutics that may enhance survival after KPE. Improving cholestasis via interruption of the enterohepatic circulation of bile acids may directly attenuate hepatic bile acid retention and reduce the risk of early organ failure. Directly addressing intrahepatic accretion of bile acids to avoid inherent bile acid toxicities provides an attractive and plausible therapeutic target for biliary atresia. This review explores the novel therapeutic concept of inhibiting the sole ileal bile acid transporter (IBAT), also known as ASBT (apical sodium-bile acid transporter, encoded by SLC10A2), as a means to reduce hepatic bile acid concentration after KPE. By reducing return of bile acids to the cholestatic liver, IBAT inhibitors may potentially lessen or delay liver damage associated with the hepatotoxicity and cholangiopathy of bile acid accumulation. The clinical programs of 2 IBAT inhibitors in development for the treatment of pediatric cholestatic liver diseases, maralixibat and odevixibat, are highlighted.

Ileal exclusion for pruritus treatment in children with progressive familial intrahepatic cholestasis and other cholestatic diseases

BACKGROUND

Pruritus is a major health-related quality-of-life burden in progressive familial intrahepatic cholestasis (PFIC) and other childhood cholestatic liver diseases. Several nontransplant surgical techniques were developed in an attempt to ameliorate symptoms and slow disease progression. Very few case-series have been published on a particular intervention, ileal exclusion (IE), which has been considered to be inferior to the other approaches.

METHODS

We conducted a single-center retrospective chart-review case-series of patients submitted to IE as the first-line surgical treatment at our institution from 1995 to 2018. The primary goal was pruritus relief, followed by survival with the native liver and improvement in biochemical parameters.

RESULTS

Eleven patients were submitted to IE, with a mean follow-up of 60 months. Complete resolution or significant reduction of pruritus was obtained in 72.7% (n = 8) of patients. One patient (9.1%) had a major postoperative complication that required surgery. No other morbidities were reported. Two cases progressed to end-stage liver disease (ESLD) within the short-term and one year after surgery.

CONCLUSIONS

This case series study shows that IE provided excellent results in pruritus control and permitted survival with the native liver. We believe IE is a safe procedure, with few associated morbidities, and should be considered more often as primary surgical treatment for PFIC and other cholestasis.

LEVEL OF EVIDENCE

IV.

Regulation of bile duct epithelial injury by hepatic CD71+ erythroid cells

Extramedullary hematopoietic cells are present in the liver of normal neonates in the first few days of life and persist in infants with biliary atresia. Based on a previous report that liver genes are enriched by erythroid pathways, we examined the liver gene expression pattern at diagnosis and found the top 5 enriched pathways are related to erythrocyte pathobiology in children who survived with the native liver beyond 2 years of age. Using immunostaining, anti-CD71 antibodies identified CD71+ erythroid cells among extramedullary hematopoietic cells in the livers at the time of diagnosis. In mechanistic experiments, the preemptive antibody depletion of hepatic CD71+ erythroid cells in neonatal mice rendered them resistant to rhesus rotavirus-induced (RRV-induced) biliary atresia. The depletion of CD71+ erythroid cells increased the number of effector lymphocytes and delayed the RRV infection of livers and extrahepatic bile ducts. In coculture experiments, CD71+ erythroid cells suppressed the activation of hepatic mononuclear cells. These data uncover an immunoregulatory role for CD71+ erythroid cells in the neonatal liver.

Extrahepatic cholangiocyte obstruction is mediated by decreased glutathione, Wnt and Notch signaling pathways in a toxic model of biliary atresia

Biliary atresia is a neonatal liver disease with extrahepatic bile duct obstruction and progressive liver fibrosis. The etiology and pathogenesis of the disease are unknown. We previously identified a plant toxin, biliatresone, responsible for biliary atresia in naturally-occurring animal models, that causes cholangiocyte destruction in in-vitro models. Decreases in reduced glutathione (GSH) mimic the effects of biliatresone, and agents that replenish cellular GSH ameliorate the effects of the toxin. The goals of this study were to define signaling pathways downstream of biliatresone that lead to cholangiocyte destruction and to determine their relationship to GSH. Using cholangiocyte culture and 3D cholangiocyte spheroid cultures, we found that biliatresone and decreases in GSH upregulated RhoU/Wrch1, a Wnt signaling family member, which then mediated an increase in Hey2 in the NOTCH signaling pathway, causing downregulation of the transcription factor Sox17. When these genes were up- or down-regulated, the biliatresone effect on spheroids was phenocopied, resulting in lumen obstruction. Biopsies of patients with biliary atresia demonstrated increased RhoU/Wrch1 and Hey2 expression in cholangiocytes. We present a novel pathway of cholangiocyte injury in a model of biliary atresia, which is relevant to human BA and may suggest potential future therapeutics.

The duodenal tube test is more specific than hepatobiliary scintigraphy for identifying bile excretion in the differential diagnosis of biliary atresia

PURPOSE

Confirmation of bile excretion into the gastrointestinal tract is important to exclude biliary atresia (BA). We compared the duodenal tube test (DTT) with hepatobiliary scintigraphy (HS) for their efficiency in detecting bile secretion.

METHODS

The subjects of this retrospective study were 47 infants who underwent both DTT and HS to diagnose or exclude BA between January 2000 and March 2018.

RESULTS

BA was diagnosed in 32 of the 47 patients, and 7 of the remaining 15 non-BA patients underwent intraoperative cholangiography. Among the various DTT parameters, the total bile acid in duodenal fluid (DF-TBA)/serum (S) gamma-glutamyl transferase (γGTP) ratio was found to be the most specific for BA, with sensitivity and specificity of 98.0-100%, respectively. One BA patient in whom cut off values were not met was a premature infant. The sensitivity and specificity of HS were 100-56.3%, respectively. The diagnostic accuracy of the DF-TBA/S-γGTP parameter was higher than that of HS (98.6% vs. 85.1%, respectively).

CONCLUSIONS

The DTT could be more a specific method than HS to detect bile excretion. Thus, the DTT should be incorporated into the multidisciplinary diagnostic approach for the differential diagnosis of BA to prevent unnecessary intraoperative cholangiography in patients who do not have BA.

Novel ABCB4 mutation in a Chinese female patient with progressive familial intrahepatic cholestasis type 3: a case report

Background

Progressive familial intrahepatic cholestasis (PFIC) is a rare group of autosomal recessive hereditary hepatic diseases. There are three types of PFIC, classified according to the mutated gene. For example, PFIC type 3 (PFIC3) is due to mutations in the ABCB4 gene (encoding multidrug-resistant protein 3 [MDR3]).

Case presentation

We present a 19-year-old Chinese female patient who had a 2-year history of recurrent liver dysfunction, with mainly elevated alkaline phosphatase and γ-glutamyl transpeptidase(γ-GT) levels. After excluding other causes of abnormal liver function and cholestasis, the final diagnosis of PFIC3 was confirmed by histopathological examination and gene detection. The immunohistochemical results showed no MDR3 protein expression in the bile duct membrane. Genetic sequencing analysis revealed a novel heterozygous 2137G > A; p. V713M mutation (Exon 17) and a synonymous 504C > T; p. N168N mutation (Exon 6) in ABCB4.

Conclusions

Our patient with long-term liver dysfunction demonstrated that elevated alkaline phosphatase and γ-GT levels should be associated with the diagnosis of PFIC3, and gene detection is the key to diagnosis. From our in silico analysis, the novel mutation p. V713M in Exon 17 was predicted to affect protein function, with a SIFT (Sorting Intolerant from Tolerant) score of 0.02, indicating a deleterious effect. Further studies are necessary to investigate the impact of the novel heterozygous 2137G > A; p. V713M mutation (Exon 17) on functional defects of MDR3 and PFIC3.

Association of common variation in ADD3 and GPC1 with biliary atresia susceptibility

Biliary atresia (BA) is an idiopathic neonatal cholestatic disease. Recent genome-wide association study (GWAS) revealed that common variation of ADD3, GPC1, ARF6, and EFEMP1 gene was associated with BA susceptibility. We aimed to evaluate the association of these genes with BA in Chinese population. Twenty single nucleotide polymorphisms (SNPs) in these four genes were genotyped in 340 BA patients and 1,665 controls. Three SNPs in ADD3 were significantly associated with BA, and rs17095355 was the top SNP (P_Allele = 3.23×10^-6). Meta-analysis of published data and current data indicated that rs17095355 was associated with BA susceptibility in Asians and Caucasians. Three associated SNPs were expression quantitative trait loci (eQTL) for ADD3. Two GPC1 SNPs in high linkage disequilibrium (LD) showed nominal association with BA susceptibility (P_Allele = 0.03 for rs6707262 and P_Allele = 0.04 for rs6750380), and were eQTL of GPC1. Haplotype harboring these two SNPs almost reached the study-wide significance (P = 0.0035). No association for ARF6 and EFEMP1 was found with BA risk in the current population. Our study validated associations of ADD3 and GPC1 SNPs with BA risk in Chinese population and provided evidence of epistatic contributions of genetic factors to BA susceptibility.

Gallbladder wall abnormality in biliary atresia of mouse Sox17+/- neonates and human infants

Biliary atresia (BA) is characterized by the inflammation and obstruction of the extrahepatic bile ducts (EHBDs) in newborn infants. SOX17 is a master regulator of fetal EHBD formation. In mouse Sox17+/- BA models, SOX17 reduction causes cell-autonomous epithelial shedding together with the ectopic appearance of SOX9-positive cystic duct-like epithelia in the gallbladder walls, resulting in BA-like symptoms during the perinatal period. However, the similarities with human BA gallbladders are still unclear. In the present study, we conducted phenotypic analysis of Sox17+/- BA neonate mice, in order to compare with the gallbladder wall phenotype of human BA infants. The most characteristic phenotype of the Sox17+/- BA gallbladders is the ectopic appearance of SOX9-positive peribiliary glands (PBGs), so-called pseudopyloric glands (PPGs). Next, we examined SOX17/SOX9 expression profiles of human gallbladders in 13 BA infants. Among them, five BA cases showed a loss or drastic reduction of SOX17-positive signals throughout the whole region of gallbladder epithelia (SOX17-low group). Even in the remaining eight gallbladders (SOX17-high group), the epithelial cells near the decidual sites were frequently reduced in the SOX17-positive signal intensity. Most interestingly, the most characteristic phenotype of human BA gallbladders is the increased density of PBG/PPG-like glands in the gallbladder body, especially near the epithelial decidual site, indicating that PBG/PPG formation is a common phenotype between human BA and mouse Sox17+/- BA gallbladders. These findings provide the first evidence of the potential contribution of SOX17 reduction and PBG/PPG formation to the early pathogenesis of human BA gallbladders.This article has an associated First Person interview with the joint first authors of the paper.

Phenotype-Genotype Correlation of North Indian Progressive Familial Intrahepatic Cholestasis type2 Children Shows p.Val444Ala and p.Asn591Ser Variants and Retained BSEP Expression

Backgrounds and Aims: Progressive familial intrahepatic cholestasis type 2 (PFIC2) is caused by a defect or deficiency of bile salt export protein (BSEP) due to mutation in the ABCB11 gene. We intend to evaluate the phenotype-genotype correlation in 10 diagnosed cases of PFIC2 in a single tertiary care center in North India. Methods: The clinical, biochemical, histopathological, immunohistochemical, ultrastructural and genetic data of the 10 diagnosed cases of PFIC2 were recorded. Results: Icterus, pruritus and bleeding manifestations were the commonest clinical symptoms. Giant cell transformation was seen in 50% of the patients. Two predominant genetic variants were ABCB11 missense p.Val444Ala (c. 1331 T > C) and ABCB11 missense p.Asn591Ser (c. 1772 A > G) in their homozygous or compound heterozygous states and were associated with retained BSEP immunopositivity and reduced but retained BSEP immunopositivity respectively. Conclusion: Retention of BSEP is common in North Indian children of PFIC2 with no phenotype-genotype correlation.

Three-color risk stratification for improving the diagnostic accuracy for biliary atresia

OBJECTIVES

It is challenging to early differentiate biliary atresia from other causes of cholestasis. We aimed to develop an algorithm with risk stratification to distinguish biliary atresia from infantile cholestasis.

METHODS

In this study, we enrolled infants with cholestasis into 2 subgroups from January 2010 to April 2019. A prospective cohort (subgroup 2) of 187 patients (107 with biliary atresia and 80 without biliary atresia) underwent acoustic radiation force impulse elastography. Stepwise regression was used to identify significant predictors of biliary atresia. A sequential algorithm with risk stratification was constructed.

RESULTS

Among 187 patients, shear wave speed > 1.35 m/s and presence of the triangular cord sign were considered high risk for biliary atresia (red), in which 73 of 78 patients (accuracy of 93.6%) with biliary atresia were identified. Afterwards, γ-GT, abnormal gallbladder, and clay stool were introduced into the algorithm and 55 intermediate-risk infants were identified (yellow) with a diagnostic accuracy of 60% for biliary atresia. Of the remaining 54 infants who were classified as low-risk patients (green), the accuracy for excluding biliary atresia was 98.1%. By applying a three-color risk stratification tool, 70.6% patients were identified as either high risk or low risk for biliary atresia (area under the curve, 0.983; sensitivity, 98.7%; specificity, 91.4%). We also estimated the risk of biliary atresia in different color groups, which was 94.7% (95%CI, 94.3-95.5%) in the red group and 7.2% (95%CI, 6.6-8.3%) in the green group.

CONCLUSIONS

Our simple noninvasive approach was able to identify biliary atresia with high accuracy.

KEY POINTS

• Five predictors, namely shear wave speed, triangle cord sign, γ-glutamyl transferase, abnormal gallbladder, and clay stool, were selected to identify biliary atresia in cholestasis. • Shear wave speed > 1.35 m/s and presence of the triangle cord sign were considered high-risk patients with a diagnostic accuracy of 93.6% for biliary atresia. • Risk for biliary atresia was high (red), intermediate (yellow), or low (green). In the red and green group, we achieved an extremely high diagnostic performance (area under the curve, 0.983; sensitivity, 98.7%; specificity, 91.4%).

Clinical Value of Serum Interleukin-33 Biomarker in Infants With Neonatal Cholestasis

OBJECTIVES

The present study aimed to estimate the value of serum interleukin-33 (IL-33) levels in infants with cholestasis, correlate serum IL-33 levels with the clinicopathological profile of infants with cholestasis, and compare its level with that of healthy infants who served as control.

METHODS

Sixty infants with cholestasis were enrolled in the present study and divided into biliary atresia (BA) group and non-BA group, in addition to 30 healthy infants as a control group. All infants were analyzed for their clinical and biochemical features, histopathological profile, and serum level of IL-33 by enzyme-linked immune sorbent assay.

RESULTS

Serum level of IL-33 in BA group (median 48.0, interquartile range: 28.9-106.2) was significantly higher than that of the non-BA group (median 17.3, interquartile range: 13.7-18.8 pg/mL) and both were higher than that of the control group. There was a positive correlation between serum IL-33 and aspartate aminotransferase, alanine aminotransferase, bilirubin (total and direct) levels, and fibrosis stage among the BA group. Serum IL-33 at a cut-off value of 20.8 pg/mL can detect BA with a specificity of 95% and a sensitivity of 96.7%.

CONCLUSION

The significantly higher production of IL-33 in patients with BA compared to non-BA suggests a potential role of IL-33 for initiation and progression of the disease process, also, IL-33 may have a diagnostic role in infants with BA.

Changes in plasma bile acid profiles after partial internal biliary diversion in PFIC2 patients

Background

We ask if plasma bile acid profiles can be used to monitor the effectiveness of partial internal biliary diversion (PIBD) for treating uncontrolled cholestasis in progressive familial intrahepatic cholestasis type 2 (PFIC2) patients.

Methods

Plasma bile acids were profiled in 3 cases of ATP-binding cassette, sub-family B member 11 (ABCB11)-mutated PFIC2 children before and after PIBD compared to healthy controls and 8 PFIC2 patients. The quantitation of bile acids was performed by reversed-phase ultrahigh-performance liquid chromatography/multiple-reaction monitoring-mass spectrometry (UPLC/MRM-MS) with negative ion detection.

Results

Before PIBD, all three patients presented with >50-fold higher levels of total plasma bile acids, 2-7 folds higher ratios of taurine: glycine conjugated primary bile acids, and unchanged secondary bile acids levels compared to healthy controls. After PIBD, only one of the three patients (P3) showed relief of cholestasis. The bile acid profiles of the two nonresponding patients showed little change while that of the responding patient showed a 5-fold reduction in total plasma primary bile acids, a reduced taurine: glycine conjugate ratio, and an unexpected 26- and 12-fold increase in secondary bile acids DCA and LCA respectively. One year later, the responder suffered a recurrence of cholestasis, and the bile acid profile shifted back to a more pre-PIBD-like profile.

Conclusions

Plasma bile acid profiles may potentially be useful as sensitive biomarkers for monitoring the clinical course of PIBD patients. Relief of cholestasis after PIBD appears to be associated with significantly increased circulating toxic secondary bile acids and this may limit the utility of PIBD in PFIC2 patients in the long run.

Irrelevance of USF2 rs916145 polymorphism with the risk of biliary atresia susceptibility in Southern Chinese children

Backgrounds: Biliary atresia (BA) is a very rare neonatal disease, however, it has been the most common cause of obstructive jaundice in infancy. The complex pathogenesis of BA is not entirely clear and a lot of possible pathogenic mechanisms have been proposed to explain the etiology of BA, including genetic, inflammatory, environmental and developmental abnormalities. As a transcription factor, USF2 gene rs916145 polymorphism has been shown to be related to the risk of BA.

Methods: We examined the USF2 rs916145 genotype in a large case–control study consisting of 506 BA patients and 1473 healthy controls, using the MassARRAY iPLEX Gold system (Sequenom). Odds ratios (ORs) and 95% confidence intervals (CIs) were used to evaluate the association between the USF2 gene rs916145 polymorphism and BA susceptibility.

Results: The frequency of different genotypes showed no statistical significance (GG/GC, OR: 1.09, P=0.470, 95% CI: 0.87–1.35; GG/CC, OR: 0.86, P=0.378, 95% CI: 0.62–1.20). No obvious association was revealed between the USF2 gene rs916145 polymorphism and BA susceptibility.

Conclusion:USF2 rs916145 polymorphism may not be the best predictor of BA.

Innate Immunity and Pathogenesis of Biliary Atresia

Biliary atresia (BA) is a devastating fibro-inflammatory disease characterized by the obstruction of extrahepatic and intrahepatic bile ducts in infants that can have fatal consequences, when not treated in a timely manner. It is the most common indication of pediatric liver transplantation worldwide and the development of new therapies, to alleviate the need of surgical intervention, has been hindered due to its complexity and lack of understanding of the disease pathogenesis. For that reason, significant efforts have been made toward the development of experimental models and strategies to understand the etiology and disease mechanisms and to identify novel therapeutic targets. The only characterized model of BA, using a Rhesus Rotavirus Type A infection of newborn BALB/c mice, has enabled the identification of key cellular and molecular targets involved in epithelial injury and duct obstruction. However, the establishment of an unleashed chronic inflammation followed by a progressive pathological wound healing process remains poorly understood. Like T cells, macrophages can adopt different functional programs [pro-inflammatory (M1) and resolutive (M2) macrophages] and influence the surrounding cytokine environment and the cell response to injury. In this review, we provide an overview of the immunopathogenesis of BA, discuss the implication of innate immunity in the disease pathogenesis and highlight their suitability as therapeutic targets.

Neonatal cholestasis: recent insights

Background

Neonatal physiological jaundice is a common benign condition that rarely extends behind the second week of life; however, it may interfere with the diagnosis of a pathological condition termed neonatal cholestasis (NC). The latter is a critical, uncommon problem characterized by conjugated hyperbilirubinaemia. This review aims to highlight the differences between physiological and pathological jaundice, identify different causes of NC, and provide a recent approach to diagnosis and management of this serious condition.

Main text

NC affects 1/2500 live births, resulting in life-threatening complications due to associated hepatobiliary or metabolic abnormalities. NC is rarely benign and indicates the presence of severe underlying disease. If jaundice extends more than 14 days in full-term infants or 21 days in preterm infants, the serum bilirubin level fractionated into conjugated (direct) and unconjugated (indirect) bilirubin should be measured. A stepwise diagnostic approach starts with obtaining a complete history, and a physical examination which are valuable for the rapid diagnosis of the underlying disease. The most frequently diagnosed causes of NC are biliary atresia (BA) and idiopathic neonatal hepatitis (INH). The early diagnosis of NC ensures more accurate management and better prognosis. Despite the unavailability of any specific treatments for some causes of NC, the patient can benefit from nutritional management and early medical intervention. Future research should attempt to shed light on methods of screening for NC, especially for causes that can be effectively treated either through proper nutritional support, appropriate chemotherapeutic management, or timely surgical intervention.

Conclusion

Further attention should be paid for diagnosis and treatment of NC as it may be misdiagnosed as physiological jaundice; this may delay the proper management of the underlying diseases and aggravates its complications.

Long Noncoding RNA H19 Contributes to Cholangiocyte Proliferation and Cholestatic Liver Fibrosis in Biliary Atresia

Biliary atresia (BA) is a neonatal liver disease featuring cholestasis and severe liver fibrosis (LF). Despite advances in the development of surgical treatment, lacking an early diagnostic marker and intervention of LF invariably leads to death from end-stage liver disease in the early years of life. We previously reported that knockout of sphingosine 1-phosphate receptor 2 (S1PR2) protected mice from bile duct ligation (BDL)-induced cholangiocyte proliferation and LF. Our recent studies further showed that both hepatic and serum exosomal long noncoding RNA H19 (lncRNAH19) levels are correlated with cholestatic injury in multidrug resistance 2 knockout (Mdr2^-/- ) mice. However, the role of lncRNAH19 in BA progression remains unclear. Here, we show that both hepatic and serum exosomal H19 levels are positively correlated with severity of fibrotic liver injuries in BA patients. H19 deficiency protects mice from BDL-induced cholangiocyte proliferation and LF by inhibiting bile-acid-induced expression and activation of S1PR2 and sphingosine kinase 2 (SphK2). Furthermore, H19 acts as a molecular sponge for members of the microRNA let-7 family, which results in up-regulation of high-mobility group AT-hook 2 (HMGA2), a known target of let-7 and enhancement of biliary proliferation. Conclusion: These results indicate that H19 plays a critical role in cholangiocyte proliferation and cholestatic liver injury in BA by regulating the S1PR2/SphK2 and let-7/HMGA2 axis. Serum exosomal H19 may represent a noninvasive diagnostic biomarker and potential therapeutic target for BA.

Quantitative Contrast-Enhanced Ultrasound by Sonazoid in the Early Diagnosis of Biliary Atresia: An Experimental Study of Rats With Bile Duct Ligation

We aimed to investigate the feasibility of quantitative Sonazoid contrast-enhanced ultrasound (CEUS) in the diagnosis of biliary atresia (BA) at an early disease stage. First, liver tissue from 10 patients with BA and 10 patients with infantile hepatitis syndrome (IHS) was immunostained with cluster of differentiation 68 (CD68) to compare Kupffer cell counts. Then, quantitative Sonazoid CEUS was performed to evaluate the hyperplasia of the artery branches during the artery phase and changes in Kupffer cell counts during the Kupffer phase in a rat model of BA (common bile duct ligation). Based on our results, liver enhancement from Kupffer cells in BA patients was significantly higher than that in IHS patients (p = 0.026 < 0.05). Furthermore, quantitative CEUS showed that the liver enhancement intensity of rats with bile duct ligation was substantially greater than that of rats without bile duct ligation during the artery phase 3 d post-operation and the Kupffer phase 5 d post-operation. The increased enhancement intensity in the Kupffer phase was in agreement with the increase in Kupffer cell counts in pathologic staining (18/20, 90%). In conclusion, quantitative Sonazoid CEUS can detect the hyperplasia of artery branches in artery phase and the increase of Kupffer cells in Kupffer phase in the liver of BA rats at an early disease stage. Therefore, Sonazoid CEUS could potentially be a valuable non-invasive alternative for the diagnosis of BA.

Identification of Polycystic Kidney Disease 1 Like 1 Gene Variants in Children With Biliary Atresia Splenic Malformation Syndrome

Biliary atresia (BA) is the most common cause of end-stage liver disease in children and the primary indication for pediatric liver transplantation, yet underlying etiologies remain unknown. Approximately 10% of infants affected by BA exhibit various laterality defects (heterotaxy) including splenic abnormalities and complex cardiac malformations-a distinctive subgroup commonly referred to as the biliary atresia splenic malformation (BASM) syndrome. We hypothesized that genetic factors linking laterality features with the etiopathogenesis of BA in BASM patients could be identified through whole-exome sequencing (WES) of an affected cohort. DNA specimens from 67 BASM subjects, including 58 patient-parent trios, from the National Institute of Diabetes and Digestive and Kidney Diseases-supported Childhood Liver Disease Research Network (ChiLDReN) underwent WES. Candidate gene variants derived from a prespecified set of 2,016 genes associated with ciliary dysgenesis and/or dysfunction or cholestasis were prioritized according to pathogenicity, population frequency, and mode of inheritance. Five BASM subjects harbored rare and potentially deleterious biallelic variants in polycystic kidney disease 1 like 1 (PKD1L1), a gene associated with ciliary calcium signaling and embryonic laterality determination in fish, mice, and humans. Heterozygous PKD1L1 variants were found in 3 additional subjects. Immunohistochemical analysis of liver from the one BASM subject available revealed decreased PKD1L1 expression in bile duct epithelium when compared to normal livers and livers affected by other noncholestatic diseases. Conclusion: WES identified biallelic and heterozygous PKD1L1 variants of interest in 8 BASM subjects from the ChiLDReN data set; the dual roles for PKD1L1 in laterality determination and ciliary function suggest that PKD1L1 is a biologically plausible, cholangiocyte-expressed candidate gene for the BASM syndrome.

[Staging of liver fibrosis in biliary atresia : Comparison of Chevallier and Ishak score as well as automated evaluation]

BACKGROUND

Biliary atresia (BA) is a rare disease of the newborn, resulting in liver cirrhosis due to obliterative cholangiopathy. Liver biopsies are commonly performed in order to confirm the diagnosis and in order to stage fibrosis.

OBJECTIVES

The present study intended to analyze two established scores for evaluating liver fibrosis focusing on the interobserver variability as well as the prognostic reliability towards the time of liver transplantation.

MATERIALS AND METHODS

Liver biopsies of BA patients between 2012 and 2015 were evaluated retrospectively by two pathologists at the Hannover Medical School (MHH) and the RWTH Aachen University Hospital. Fibrosis was measured using Ishak and Chevallier scores. Furthermore, a computerized automatically algorithm-based analyzation (ABAA) was performed. Results were evaluated towards the time point of liver transplantation and hepatoportoenterostomy (HPE).

RESULTS

Overall, 34 liver biopsies were analyzed. The Ishak score showed a remarkable interobserver variability (Κ_W = 0.68) while the Chevallier score was proven to have a poor interobserver variability (Fleiss' Κappa = -0.01). However, both scores were correlated positively, as was the ABAA (p < 0.001). Regarding prognostic reliability, ROC analyses of the Ishak score revealed the best validity towards an early liver transplantation within 12 months (AUC 0.813, p = 0.011). In addition, an increased Ishak score ≥4 reduced the survival time with the native liver (hazard ratio 6.6 [95% CI 1.9-23.3]).

CONCLUSIONS

The Ishak score was revealed to have the best interobserver variability as well as prognostic validity towards an early liver transplantation in BA patients. Due to its easy applicability, the Ishak score was proven superior in comparison to the Chevallier score and ABAA. Therefore, use of the Ishak score is recommended in daily clinical routine for analyzing liver biopsies in BA patients.

Regenerative Medicine of the Bile Duct: Beyond the Myth

Cholangiopathies are rare diseases of the bile duct with high mortality rates. The current treatment for cholangiopathies is liver transplantation, but there are significant obstacles including a shortage of donors and a high risk of complications. Currently, there is only one available medicine on the market targeting cholangiopathies, and the results have been inadequate in clinical therapy. To overcome these obstacles, many researchers have used human induced pluripotent stem cells (hPSC) as a source for cholangiocyte-like cell generation and have incorporated advances in bioprinting to create artificial bile ducts for implantation and transplantation. This has allowed the field to move dramatically forward in studies of biliary regenerative medicine. In this review, the authors provide an overview of cholangiocytes, the organogenesis of the bile duct, cholangiopathies, and the current treatment and advances that have been made that are opening new doors to the study of cholangiopathies.

Biliary atresia: 20-40-year follow-up with native liver in an Italian centre

INTRODUCTION

Biliary atresia (BA) represents the leading indication for liver transplantation in childhood. Only few studies reported the outcome of patients who survived more than 20 years on their native liver, and up to date there are no Italian data available. We reported our 40-year single centre experience with long-term follow-up of BA patients.

MATERIALS AND METHODS

All consecutive patients who underwent Kasai portoenterostomy (KPE) for BA managed at our Institution between 1975 and 1996 were retrospectively reviewed. Native liver (NLS) and overall survival (OS) were analyzed with Kaplan-Meyer curves and LogRank test. A p value of <.05 was regarded as significant. Quality of life of patients currently surviving with their native liver was assessed through a quality of life questionnaire.

RESULTS

During the 22-year period of the study 174 patients underwent surgery (median age 60 days). Clearance of jaundice at 6 months from surgery was achieved in 90 patients (51.7%). NLS was 41% at 5 years, 32% at 10 years, 17.8% at 20 years and 14.9% at 40 years. Cholangitis was recorded in 32%, hepatocellular carcinoma in 0.5%. Twenty-six patients (14.9%) survived with their liver more than 20 years; 84.6% had normal serum bilirubin level and 23% had esophageal varices. Quality of life was comparable with the healthy Italian population in all but one patient.

CONCLUSIONS

Our Italian experience confirms KPE represents the cornerstone of treatment for children with BA. Multidisciplinary and meticulous lifelong post-operative follow-up should be guaranteed for these patients because of the possibility of late-onset cholangitis, portal hypertension, hepatic deterioration and liver malignant tumors.

TYPE OF THE STUDY

retrospective case series.

LEVEL OF EVIDENCE

IV.

Neonatal cholestasis: emerging molecular diagnostics and potential novel therapeutics

Neonatal cholestasis is a group of rare disorders of impaired bile flow characterized by conjugated hyperbilirubinaemia in the newborn and young infant. Neonatal cholestasis is never physiological but rather is a sign of hepatobiliary and/or metabolic disorders, some of which might be fatal if not identified and treated rapidly. A step-wise timely evaluation is essential to quickly identify those causes amenable to treatment and to offer accurate prognosis. The aetiology of neonatal cholestasis now includes an expanding group of molecularly defined entities with overlapping clinical presentations. In the past two decades, our understanding of the molecular basis of many of these cholestatic diseases has improved markedly. Simultaneous next-generation sequencing for multiple genes and whole-exome or whole-genome sequencing now enable rapid and affordable molecular diagnosis for many of these disorders that cannot be directly diagnosed from standard blood tests or liver biopsy. Unfortunately, despite these advances, the aetiology and optimal therapeutic approach of the most common of these disorders, biliary atresia, remain unclear. The goals of this Review are to discuss the aetiologies, algorithms for evaluation and current and emerging therapeutic options for neonatal cholestasis.

The Pediatric Cell Atlas: Defining the Growth Phase of Human Development at Single-Cell Resolution

Single-cell gene expression analyses of mammalian tissues have uncovered profound stage-specific molecular regulatory phenomena that have changed the understanding of unique cell types and signaling pathways critical for lineage determination, morphogenesis, and growth. We discuss here the case for a Pediatric Cell Atlas as part of the Human Cell Atlas consortium to provide single-cell profiles and spatial characterization of gene expression across human tissues and organs. Such data will complement adult and developmentally focused HCA projects to provide a rich cytogenomic framework for understanding not only pediatric health and disease but also environmental and genetic impacts across the human lifespan.

Hepatocyte growth factor levels in livers and serum at Kasai-portoenterostomy are not predictive of clinical outcome in infants with biliary atresia

Biliary atresia (BA) is characterized by progressive destruction of the biliary system leading to liver fibrosis and deterioration of liver function. Serum hepatocyte growth factor (HGF) has been shown to be increased in cirrhotic diseases including BA. The aim of this study was to investigate the prognostic value of HGF levels in sera and liver tissue for the further disease course. A total of 49 serum and liver samples from infants with BA were acquired during Kasai-portoenterostomy (KPE) and analyzed by multiplex immunoassay including HGF, as marker of liver regeneration, and Interleukin 6 (IL-6) as a marker of inflammation. Both mediators showed no correlation with the outcome defined as favorable (survival with native liver (SNL)) or, in contrast, rapid deterioration of liver function requiring transplantation. Our data suggest that the degree of liver regeneration indicated by high levels of HGF within the liver is a dismissible factor in the post-KPE disease course.

Suppressing microRNA-29c promotes biliary atresia-related fibrosis by targeting DNMT3A and DNMT3B

This study was designed to investigate the potential role of microRNA-29c (miR-29c) in biliary atresia-related fibrosis. The expression of miR-29c was determined in 15 pairs of peripheral blood samples from infants with biliary atresia (BA) and infants with non-BA neonatal cholestasis using quantitative real-time PCR. EMT was established by induction with TGF-β1 in HIBEpiC cells. MiR-29c was inhibited by lipofectamine transfection. The expressions of proteins related to epithelial-mesenchymal transition (EMT), i.e., E-cadherin, N-cadherin and vimentin, were determined using quantitative real-time PCR and western blotting. Direct interaction between miR-29c and DNMT3A and DNMT3B was identified using a luciferase reporter assay. The expressions of DNMT3A and DNMT3B were suppressed by treatment with SGI-1027. Patients with BA showed significantly lower miR-29c levels in peripheral blood samples than the control subjects. In vitro, TGF-β1-induced EMT significantly decreased the expression of miR-29c. Downregulation of miR-29c had a promotional effect on BA-related fibrosis in HIBEpiC cells, as confirmed by the decrease in E-cadherin and increase in N-cadherin and vimentin levels. MiR-29c was found to target the 3'UTR of DNMT3A and DNMT3B and inhibit their expression. Suppression of DNMT3A and DNMT3B reversed the effects of miR-29c downregulation on BA-related fibrosis in HIBEpiC cells. These data suggest that BA-related fibrosis is closely associated with the occurrence of EMT in HIBEpiC cells. MiR-29c might be a candidate for alleviating BA-related fibrosis by targeting DNMT3A and DNMT3B.

Alloimmunity and Cholestasis After Liver Transplantation in Children With Progressive Familial Intrahepatic Cholestasis

OBJECTIVES

Bile salt export pump (BSEP) deficiency is an important reason for chronic cholestasis leading to liver transplantation (LT) in early childhood. The underlying pathology is a dysfunction of BSEP due to various mutations in the ABCB11 gene. Cases of clinical recurrence after LT due to alloantibodies directed against BSEP (antibody-induced BSEP deficiency [AIBD]) have been reported. Most of these patients could be controlled by intensified immunosuppression.

METHODS

We here report on 3 children with BSEP-deficiency and end-stage liver disease, which developed AIBD after LT refractory to extensive immunosuppressive and immunomodulatory treatments; retransplantation was necessary in all 3 patients. In 1 patient, a stem cell transplantation was performed successfully.

RESULTS

AIBD seems to be induced by triggering factors such as initial impaired graft function or infections after LT.

CONCLUSIONS

The underlying mutation may play a role in this process. Intensifying immunosuppression may be able to control AIBD, but some cases seem to be refractory to treatment and require retransplantation. Stem cell transplantation may provide a new therapeutic option for cases refractory to conservative treatment.

Th17-associated cytokines multiplex testing indicates the potential of macrophage inflammatory protein-3 alpha in the diagnosis of biliary atresia

BACKGROUND & AIMS

Biliary atresia (BA) is a neonatal obliterative cholangiopathy with high prevalence in south China. Accurate identification of BA among infants with obstructive jaundice is still difficult by noninvasive diagnostic tools. Th17 cells have been reported closely related with the development of BA, which suggest that Th17-associated cytokines were potential biomarkers for the diagnosis of BA patients.

METHODS

In the training study, 76 infants who were divided into 2 groups, including BA group (n = 31) and non-BA jaundice group (n = 45). Clinical and routine laboratory data were collected from all subjects. Totally 25 Th17-associated cytokines were tested and compared between groups. The diagnostic value of each differential cytokine was evaluated by the area under the receiver operating characteristic curve (AUC). The best potential diagnostic biomarker was further validated in a cohort including 68 jaundice infants from our partnering institution in a blinded fashion.

RESULTS

Data from the training study showed that gamma-glutamyl transferase (GGT) and clay stool would be helpful in the identification of BA patients in jaundice subjects. Th17-associated cytokines assay indicated that IL-17F, IL-10, macrophage inflammatory protein-3alpha (MIP3a), IL-22, IL-13, IL-33, IL-6, IL-17E, IL-27, IL-31, TNF-a and TNF-b were differentially expressed in BA patients, and the AUC of MIP3a was higher than other markers. MIP3a alone or combined with other laboratory data would significantly increase the diagnostic accuracy of BA. The diagnostic value of MIP3a was further confirmed in our validation study.

CONCLUSION

MIP3a alone or combined with other laboratory data would significantly increase the diagnostic accuracy of BA.

Cytokine-Producing B Cells Promote Immune-Mediated Bile Duct Injury in Murine Biliary Atresia

Biliary atresia (BA) is a neonatal T cell-mediated, inflammatory, sclerosing cholangiopathy. In the rhesus rotavirus (RRV)-induced neonatal mouse model of BA (murine BA), mice lacking B cells do not develop BA, and the lack of B cells is associated with loss of T-cell and macrophage activation. The aim of this study was to determine the mechanism of B cell-mediated immune activation (antigen presentation versus cytokine production) in murine BA. Normal neonatal B cells in the liver are predominantly at pro-B and pre-B cellular development. However, BA mice exhibit a significant increase in the number and activation status of mature liver B cells. Adoptively transferred B cells into RRV-infected, B cell-deficient mice were able to reinstate T-cell and macrophage infiltration and biliary injury. Nonetheless, neonatal liver B cells were incompetent at antigen presentation to T cells. Moreover, 3-83 immunoglobulin transgenic mice, in which B cells only present an irrelevant antigen, developed BA, indicating a B-cell antigen-independent mechanism. B cells from BA mice produced a variety of innate and adaptive immune cytokines associated with immune activation. In vitro trans-well studies revealed that BA B cells secreted cytokines that activated T cells based on increased expression of T-cell activation marker cluster of differentiation 69. Conclusion: Neonatal liver B cells are highly activated in murine BA and contribute to immune activation through production of numerous cytokines involved in innate and adaptive immunity; this work provides increased knowledge on the capacity of neonatal B cells to contribute to an inflammatory disease through cytokine-mediated mechanisms, and future studies should focus on targeting B cells as a therapeutic intervention in human BA.

Prevention of Cell Growth by Suppression of Villin Expression in Lithocholic Acid-Stimulated HepG2 Cells

Cholestasis is a condition wherein bile flow is interrupted and lithocholic acid is known to play a key role in causing severe liver injury. In this study, we performed in-depth analysis of the morphological changes in bile canaliculi and the biological role of villin in cholestasis using lithocholic acid-stimulated HepG2 human hepatocarcinoma cells. We confirmed disruption of the bile canaliculi in liver sections from a liver allograft patient with cholestasis. Lithocholic acid caused strong cytotoxicity in HepG2 cells, which was associated with abnormal morphology. Lithocholic acid reduced villin expression, which recovered in the presence of nuclear receptor agonists. Furthermore, villin mRNA expression increased following small interfering RNA (siRNA)-mediated knockdown of the nuclear farnesoid X receptor and pregnane X receptor. Villin knockdown using siRNA caused cell growth arrest in HepG2 cells. The effect of villin-knockdown on whole-genome expression in HepG2 cells was analyzed by DNA microarray. Our data suggest that lithocholic acid caused cell growth arrest by suppressing villin expression via farnesoid X receptor and pregnane X receptor in HepG2 cells.

Comprehensive Review of Molecular Mechanisms during Cholestatic Liver Injury and Cholangiocarcinoma

Cholestatic liver injury is characterized by damage induced on the biliary tree and cholangiocytes, the cells lining the biliary tree, thus they are termed "cholangiopathies". Cholangiopathies include diseases such as Primary Biliary Cholangitis, Primary Sclerosing Cholangitis, Biliary Atresia and Cholangiocarcinoma. These pathologies lack viable therapies and most patients are diagnosed during late stage disease progression (with the exception of Biliary Atresia, which is found shortly after birth). The lack of therapies for these diseases has put a significant burden on the need for liver transplantation as this is the only indicative "cure" for cholangiopathies. The molecular mechanisms for cholangiopathies have been extensively studied; however, and unfortunately, the lack of effective biomarkers and therapeutics remains. In this review article we highlight the latest studies to investigate the molecular mechanisms regulating cholangiopathies and the potential therapeutics that might be discovered.

Biliary Atresia: Clinical and Research Challenges for the Twenty-First Century

Biliary atresia (BA) is a fibroinflammatory disease of the intrahepatic and extrahepatic biliary tree. Surgical hepatic portoenterostomy (HPE) may restore bile drainage, but progression of the intrahepatic disease results in complications of portal hypertension and advanced cirrhosis in most children. Recognizing that further progress in the field is unlikely without a better understanding of the underlying cause(s) and pathogenesis of the disease, the National Institutes of Diabetes and Digestive and Kidney Diseases (NIDDK) sponsored a research workshop focused on innovative and promising approaches and on identifying future areas of research. Investigators discussed recent advances using gestational ultrasound and results of newborn BA screening with serum direct (conjugated) bilirubin that support a prenatal onset of biliary injury. Experimental and human studies implicate the toxic properties of environmental toxins (e.g., biliatresone) and of viruses (e.g., cytomegalovirus) to the biliary system. Among host factors, sequence variants in genes related to biliary development and ciliopathies, a notable lack of a cholangiocyte glycocalyx and of submucosal collagen bundles in the neonatal extrahepatic bile ducts, and an innate proinflammatory bias of the neonatal immune system contribute to an increased susceptibility to damage and obstruction following epithelial injury. These advances form the foundation for a future research agenda focused on identifying the environmental and host factor(s) that cause BA, the potential use of population screening, studies of the mechanisms of prominent fibrosis in young infants, determinations of clinical surrogates of disease progression, and the design of clinical trials that target subgroups of patients with initial drainage following HPE. (Hepatology 2018; 00:000-000).

Non-invasive urinary metabolomic profiles discriminate biliary atresia from infantile hepatitis syndrome

INTRODUCTION

Neonatal cholestatic disorders are a group of hepatobiliary diseases occurring in the first 3 months of life. The most common causes of neonatal cholestasis are infantile hepatitis syndrome (IHS) and biliary atresia (BA). The clinical manifestations of the two diseases are too similar to distinguish them. However, early detection is very important in improving the clinical outcome of BA. Currently, a liver biopsy is the only proven and effective method used to differentially diagnose these two similar diseases in the clinic. However, this method is invasive. Therefore, sensitive and non-invasive biomarkers are needed to effectively differentiate between BA and IHS. We hypothesized that urinary metabolomics can produce unique metabolite profiles for BA and IHS.

OBJECTIVES

The aim of this study was to characterize urinary metabolomic profiles in infants with BA and IHS, and to identify differences among infants with BA, IHS, and normal controls (NC).

METHODS

Urine samples along with patient characteristics were obtained from 25 BA, 38 IHS, and 38 NC infants. A non-targeted gas chromatography-mass spectrometry (GC-MS) metabolomics method was used in conjunction with orthogonal partial least squares discriminant analysis (OPLS-DA) to explore the metabolomic profiles of BA, IHS, and NC infants.

RESULTS

In total, 41 differentially expressed metabolites between BA vs. NC, IHS vs. NC, and BA vs. IHS were identified. N-acetyl-D-mannosamine and alpha-aminoadipic acid were found to be highly accurate at distinguishing between BA and IHS.

CONCLUSIONS

BA and IHS infants have specific urinary metabolomic profiles. The results of our study underscore the clinical potential of metabolomic profiling to uncover metabolic changes that could be used to discriminate BA from IHS.

Dual catenin loss in murine liver causes tight junctional deregulation and progressive intrahepatic cholestasis

β-Catenin, the downstream effector of the Wnt signaling, plays important roles in hepatic development, regeneration, and tumorigenesis. However, its role at hepatocyte adherens junctions (AJ) is relatively poorly understood, chiefly due to spontaneous compensation by γ-catenin. We simultaneously ablated β- and γ-catenin expression in mouse liver by interbreeding β-catenin-γ-catenin double-floxed mice and Alb-Cre transgenic mice. Double knockout mice show failure to thrive, impaired hepatocyte differentiation, cholemia, ductular reaction, progressive cholestasis, inflammation, fibrosis, and tumorigenesis, which was associated with deregulation of tight junctions (TJ) and bile acid transporters, leading to early morbidity and mortality, a phenotype reminiscent of progressive familial intrahepatic cholestasis (PFIC). To address the mechanism, we specifically and temporally eliminated both catenins from hepatocytes using adeno-associated virus 8 carrying Cre-recombinase under the thyroid-binding globulin promoter (AAV8-TBG-Cre). This led to a time-dependent breach of the blood-biliary barrier associated with sequential disruption of AJ and TJ verified by ultrastructural imaging and intravital microscopy, which revealed unique paracellular leaks around individual hepatocytes, allowing mixing of blood and bile and leakage of blood from one sinusoid to another. Molecular analysis identified sequential losses of E-cadherin, occludin, claudin-3, and claudin-5 due to enhanced proteasomal degradation, and of claudin-2, a β-catenin transcriptional target, which was also validated in vitro.

CONCLUSION

We report partially redundant function of catenins at AJ in regulating TJ and contributing to the blood-biliary barrier. Furthermore, concomitant hepatic loss of β- and γ-catenin disrupts structural and functional integrity of AJ and TJ via transcriptional and posttranslational mechanisms. Mice with dual catenin loss develop progressive intrahepatic cholestasis, providing a unique model to study diseases such as PFIC. (Hepatology 2018;67:2320-2337).

Wait-list mortality of young patients with Biliary atresia: Competing risk analysis of a eurotransplant registry-based cohort

Liver transplantation (LT) is the standard treatment for biliary atresia (BA) patients with end-stage liver disease. The prognosis after LT has steadily improved, but overall prognosis of BA patients is also determined by mortality before LT. We aimed to quantify mortality in young BA patients on the Eurotransplant waiting list and to determine the effect of disease severity and age at time of listing on pretransplant mortality. We used a cohort study design, which incorporated data from the Eurotransplant registry. Participants were 711 BA patients who were below 5 years of age from 5 countries and listed for LT between 2001 and 2014. We applied a competing risk analysis to evaluate simultaneously the outcomes death, LT, and still waiting for a suitable organ. We used Cox proportional hazards regression to assess 2-year mortality. In a subcohort of 416 children, we performed multivariate analyses between 2-year mortality and disease severity or age, each at listing. Disease severity at listing was quantified by the Model for End-Stage Liver Disease (MELD) score, which assesses bilirubin, creatinine, albumin, and international normalized ratio as continuous variables. Two-year wait-list mortality was 7.9%. Age below 6 months and MELD score above 20 points, each at listing, were strongly and independently associated with 2-year mortality (each P < 0.001). A total of 21% of infants who fulfilled both criteria did not survive the first 6 months on the waiting list. In conclusion, our findings quantify mortality among young BA patients on the waiting list and the relative importance of risk factors (age and severity of disease at listing). Our results provide both an evidence base to rationally address high mortality in subgroups and a methodology to assess effects of implemented changes, for example, in allocation rules. Liver Transplantation 24 810-819 2018 AASLD.

Role of viruses in biliary atresia: news from mice and men

Biliary atresia (BA) is still an enigmatic disease of unknown etiology and cryptic pathomechanism. Despite the fact that BA is rated among rare diseases, it represents the most frequent indication for pediatric liver transplantation. Although every effort is made to elucidate the origin of the ongoing deterioration of liver function, no breakthrough has so far been achieved, which switches the surgical but symptomatic therapy to a cause-oriented approach. The nowadays leading hypothesis focuses on hepatotropic virus as a triggering agent for an autoimmunological self-limiting inflammatory process along the entire biliary tree. The present review highlights the current state of research on the factor "viruses in biliary atresia" in both patients undergoing the Kasai procedure and the virus-induced BA mouse model.

Increased expression of senescence-associated cell cycle regulators in the progression of biliary atresia: an immunohistochemical study

AIMS

Cellular senescence plays a role in tumour suppression and in the pathogenesis of various non-neoplastic diseases, including primary biliary cholangitis and other adult cholangiopathies. Less is known about the role of cellular senescence in cholangiopathies in children. With that in mind, we examined the expression of senescence-associated cell cycle regulators in biliary atresia, the most common form of paediatric obliterative cholangiopathy.

METHODS AND RESULTS

The expression of senescence-associated cell cycle regulators (p16^Ink4a and p21^WAF1/Cip1 ) and a ductular reaction related marker (neural cell adhesion molecule: NCAM) was examined in bile ducts and bile ductules in liver samples taken from the patients with biliary atresia [n = 80; including 23 samples at the time of the Kasai procedure (KP) and 63 obtained from the explanted liver (LT) (six cases with samples at both surgical stages of disease)] and from appropriate controls (n = 17). The degree of ductular reaction and cholestasis was significantly more extensive in LT than KP (P < 0.01). The expression of p16^INK4a and NCAM was significantly more extensive in bile ducts and bile ductules in ductular reaction in both KP and LT compared to controls and in LT compared to KP (P < 0.05). The expression of p21^WAF1/Cip1 was significantly more extensive in bile ducts and bile ductules in KP compared to both LT and controls (P < 0.01).

CONCLUSIONS

Cellular senescence may play a role in the progression of bile duct loss in biliary atresia in a manner similar to that of adult cholangiopathies.

Clinical phenotype and molecular analysis of a homozygous ABCB11 mutation responsible for progressive infantile cholestasis

The bile salt export pump (BSEP) plays an important role in biliary secretion. Mutations in ABCB11, the gene encoding BSEP, induce progressive familial intrahepatic cholestasis type 2 (PFIC2), which presents with severe jaundice and liver dysfunction. A less severe phenotype, called benign recurrent intrahepatic cholestasis type 2, is also known. About 200 missense mutations in ABCB11 have been reported. However, the phenotype-genotype correlation has not been clarified. Furthermore, the frequencies of ABCB11 mutations differ between Asian and European populations. We report a patient with PFIC2 carrying a homozygous ABCB11 mutation c.386G>A (p.C129Y) that is most frequently reported in Japan. The pathogenicity of BSEP^C129Y has not been investigated. In this study, we performed the molecular analysis of this ABCB11 mutation using cells expressing BSEP^C129Y. We found that trafficking of BSEP^C129Y to the plasma membrane was impaired and that the expression of BSEP^C129Y on the cell surface was significantly lower than that in the control. The amount of bile acids transported via BSEP^C129Y was also significantly lower than that via BSEP^WT. The transport activity of BSEP^C129Y may be conserved because the amount of membrane BSEP^C129Y corresponded to the uptake of taurocholate into membrane vesicles. In conclusion, we demonstrated that c.386G>A (p.C129Y) in ABCB11 was a causative mutation correlating with the phenotype of patients with PFIC2, impairment of biliary excretion from hepatocytes, and the absence of canalicular BSEP expression in liver histological assessments. Mutational analysis in ABCB11 could facilitate the elucidation of the molecular mechanisms underlying the development of intrahepatic cholestasis.

Access to care in rare liver diseases: New challenges and new opportunities

Patients with rare diseases are often disadvantaged, particularly those with rare liver diseases. Reasons for disadvantage include delayed or overlooked diagnosis, lack of local expertise and high-quality care, poor scientific understanding of the disease process and limited therapeutic options. In adult liver disease this can be compounded by prejudices towards patients with liver disease in general, because of a perception (incorrect for all rare liver diseases) that liver disease is lifestyle related and thus "self-inflicted". In paediatric rare liver diseases, such as biliary atresia, optimising outcomes requires a particularly timely diagnosis. Irrespective of patient age, the scientific and medical community must rise to the challenge of advancing our understanding of rare liver disease, searching for more effective and specific therapies, and providing the infrastructure to provide the best care for all patients, infants, children, young and older adults. The European Reference Network for Rare Liver Diseases is an important step in this direction.

PHB2 interacts with LC3 and SQSTM1 is required for bile acids-induced mitophagy in cholestatic liver

Mitophagy is a major pathway for clearance of injured mitochondria. However, whether mitophagy is involved in the cholestasis-induced damages of hepatic mitochondria remains unknown. We here aimed to investigate the molecular links between cholestasis and hepatic mitophagy. We show that mitophagy is increased significantly in livers of biliary atresia (BA) that is cholestatic disease in infants. The mitochondrial-toxicity bile acids treatment increases the activities of mitophagy in hepatocytes. Mechanistically, we find that the prohibitin 2 (PHB2) is crucial for cholestasis-mediated mitophagy in vitro. On the one hand, PHB2 binds the autophagosomal membrane-associated protein LC3 upon injured mitochondria via an LC3-interaction region domain. On the other hand, PHB2 forms a ternary protein complex with sequestosome 1 (SQSTM1) and LC3, leading to loading of LC3 onto the damaged mitochondria. Altogether, our study suggests that PHB2 is required for cholestasis-induced mitophagy via LC3 onto the injured mitochondria.

Association of polymorphism in the VEGFA gene 3'-UTR +936T/C with susceptibility to biliary atresia in a Southern Chinese Han population

BACKGROUND

Biliary atresia (BA) is a neonatal disease characterized by chronic inflammation of the bile ducts and progressive aggravation of jaundice, but with a poor prognosis and high mortality. The etiology of BA is still uncertain which may be related to gene defect, virus infection, immune disorder, gene polymorphism. As a proinflammatory cytokine, VEGFA gene polymorphism (rs3025039) has been shown to be related to the pathogenesis of BA in Taiwanese population.

METHODS

We investigated the association between VEGFA gene polymorphism (rs3025039) and BA susceptibility using the largest case-control cohort, totaling with 506 BA patients and 1473 healthy controls in a Southern Chinese Han population. VEGFA gene polymorphism (rs3025039) was genotyped using the MassARRAY iPLEX Gold system (Sequenom). Odds ratios (OR) and 95% confidence intervals (CIs) were used to access the association between the VEGFA gene polymorphism (rs3025039) and BA risk.

RESULTS

No significant association was found between the VEGFA gene polymorphism (rs3025039) and BA risk in the overall analysis.

CONCLUSION

These results suggest that VEGFA gene polymorphism (rs3025039) may not be associated with the risk of BA in the Southern Chinese Han population.

Liver transplantation for decompensated liver cirrhosis caused by progressive familial intrahepatic cholestasis type 3: A case report

RATIONALE

Progressive familial intrahepatic cholestasis (PFIC) type 3, characterized by high gamma glutamyl transferase (GGT), is an autosomal recessive genetic disease. It often occurs in patients' first years of age. However, high GGT type PFIC is still rare.

PATIENT CONCERNS

The present study reports a case of liver transplantation for decompensated liver cirrhosis caused by PFIC type 3. An 18-year-old male presented with a history of abdominal distension and jaundice for 2 months. He had abdominal tenderness but no rebounding pain. Moreover, his dullness was felt over the liver and the spleen was palpable 8 cm below the ribs.

DIAGNOSES

Computed tomography and magnetic resonance cholangiopancreato graphy of the upper abdomen revealed cirrhosis, portal hypertension, collateral circulation formation, large spleen, and ascites. Blood biochemistry showed high alanine transaminase, aspartate transaminase, and GGT. The diagnosis of decompensated liver cirrhosis caused by PFIC-3 was finally confirmed by plasma gene detecting.

INTERVENTIONS

The patient received an open surgery named allogeneic liver transplantation after successful matching of immune types between the recipient and donor. Peritoneal puncture and catheter drainage under B-ultrasound was performed when an encapsulated effusion between the liver and stomach arose.

OUTCOMES

The patient was discharged without specific discomfort and was almost free of fluid accumulation 51 days after the surgery. At the 6-month follow-up, he had no discomfort and the blood routine, liver functions showed no abnormalities.

LESSONS

We found a new mutant fragment of ABCB4 gene in the process of diagnosis. Liver transplantation remains the most definitive treatment for PFIC. Current medical therapies and surgical interventions such as biliary diversion have potentially created a synergistic outcome.

Biliary atresia: unity in diversity

Biliary atresia (BA) is a rare disease of unknown origin and unsatisfying outcome. Single, multicenter and national evaluations of epidemiological and outcome data on BA have been periodically published over the course of decades. However, the diversity of the registered parameters and outcome measures impede comparability and cumulative analysis of these very worthwhile studies. Taking into account the fact that BA is a good example of translational research and transition of patients from pediatric surgery and hepatology to transplant surgery and hepatology in general, the interdisciplinary community should make every effort to develop a common platform upon which further activities are conducted. Extending this topic to BA-related diseases might increase the acceptance of research studies and enhance the effectiveness of any recommendations outlined therein. The use of the Internet-based communication platform and registry on http://www.bard-online.com represents the first step in this direction, and the database should be viewed as a helpful tool that guides further activities.

Minimally Invasive Hepatobiliary Surgery

Comparative studies and large-scale case series that confirm the advantages of laparoscopy in children with hepatobiliary diseases are scarce, and the use of laparoscopy remains a matter of debate. This article reviews the current literature on the role of laparoscopic and robotic surgery in pediatric patients with choledochal cyst, biliary atresia, gallbladder diseases, and hepatobiliary malignancies. Studies were identified through a search of the MEDLINE database. Laparoscopy may be beneficial for resection of choledochal cyst and cholecystectomy. However, more data are required before recommendations on the use of minimally invasive techniques for other hepatobiliary conditions can be published.

Newborn screening for biliary atresia in the United States

Despite advances in our understanding of the pathogenesis of biliary atresia (BA), BA remains the most common cause of end-stage liver disease in children and the leading indication for pediatric liver transplantation. Age at time of Kasai portoenterostomy (KPE), performed to provide bile drainage, strongly correlates with transplant-free survival, mostly due to progression of intrahepatic fibrosis to cirrhosis. Unfortunately, challenges remain in recognizing that a jaundiced infant may have BA. To better diagnose infants with BA at an earlier age, population-based screening programs in countries such as Taiwan, Japan, and China have utilized stool color cards. Early results have been promising demonstrating earlier diagnosis, earlier KPE, and, hence, improved outcomes. Cost-effectiveness studies focused on stool color card screening in North America where the incidence of BA is much lower also project improved transplant-free survival rate with a savings in terms of healthcare expenditure. There is also evidence that postnatal serum bilirubin levels may also be effective as a screening tool given that all infants with BA exhibit hyperbilirubinemia at birth. The American Academy of Pediatrics (AAP) recently advocated studying the implementation of newborn screening for BA in the United States. Further efforts and analyses within the United States are ongoing, but current evidence is supportive of screening for BA even in low incidence countries.

Chronic liver disease is universal in children with biliary atresia living with native liver

AIM

To examine the medical status of children with biliary atresia (BA) surviving with native livers.

METHODS

In this cross-sectional review, data collected included complications of chronic liver disease (CLD) (cholangitis in the preceding 12 mo, portal hypertension, variceal bleeding, fractures, hepatopulmonary syndrome, portopulmonary hypertension) and laboratory indices (white cell and platelet counts, total bilirubin, albumin, international normalized ratio, alanine aminotransferase, aspartate aminotransferase, γ-glutamyl transpeptidase). Ideal medical outcome was defined as absence of clinical evidence of CLD or abnormal laboratory indices.

RESULTS

Fifty-two children [females = 32, 62%; median age 7.4 years, n = 35 (67%) older than 5 years] with BA (median age at surgery 60 d, range of 30 to 148 d) survived with native liver. Common complications of CLD noted were portal hypertension (40%, n = 21; 2 younger than 5 years), cholangitis (36%) and bleeding varices (25%, n = 13; 1 younger than 5 years). Fifteen (29%) had no clinical complications of CLD and three (6%) had normal laboratory indices. Ideal medical outcome was only seen in 1 patient (2%).

CONCLUSION

Clinical or laboratory evidence of CLD are present in 98% of children with BA living with native livers after hepatoportoenterostomy. Portal hypertension and variceal bleeding may be seen in children younger than 5 years of age, underscoring the importance of medical surveillance for complications of BA starting at a young age.