Potential etiologies of biliary atresia

Incidence of Isolated Biliary Atresia during the COVID Lockdown in Europe: Results from a Collaborative Project by RARE-Liver

BACKGROUND

Biliary atresia (BA) is a rare cholangiopathy where one of the proposed aetiological mechanisms is an infectious viral trigger. Coronavirus disease-19 (COVID) lockdown restrictions were implemented to reduce the transmission of infections. Strictness of lockdown varied across European countries. This study aimed to investigate if there was an association between strictness of lockdown and change in isolated BA (IBA) incidence in Europe.

METHODS

We approached European centres involved in the European Reference Network RARE-LIVER. We included IBA patients born between 2015 and June 2020. We calculated the number of IBA patients born per centre per month. The Stringency Index (SI) was used as lockdown strictness indicator. The association between percentage change of mean number of IBA patients born per month and the SI was assessed.

RESULTS

We included 412 IBA patients from thirteen different centres. The median number of patients per month did not change: 6 (1-15) pre-lockdown and 7 (6-9) during lockdown (p = 0.34). There was an inverse association between SI and percentage change in IBA (B = -0.73, p = 0.03). Median age at Kasai portoenterostomy (days) did not differ between time periods (51 (9-179) vs. 53 (19-126), p = 0.73).

CONCLUSION

In this European study, a stricter COVID-lockdown was seemingly accompanied by a simultaneous larger decrease in the number of IBA patients born per month in the lockdown. Results should be interpreted with caution due to the assumptions and limitations of the analysis.

Cellular Therapies in Pediatric Liver Diseases

Liver transplantation is the gold standard for the treatment of pediatric end-stage liver disease and liver based metabolic disorders. Although liver transplant is successful, its wider application is limited by shortage of donor organs, surgical complications, need for life long immunosuppressive medication and its associated complications. Cellular therapies such as hepatocytes and mesenchymal stromal cells (MSCs) are currently emerging as an attractive alternative to liver transplantation. The aim of this review is to present the existing world experience in hepatocyte and MSC transplantation and the potential for future effective applications of these modalities of treatment.

Detection of Cytomegalovirus Infection in Infants with Biliary Atresia: A Meta-analysis

Objectives  Biliary atresia (BA) is the most common indication of liver transplantation in children. Several reports attributed BA to both prenatal and perinatal etiologies, including a viral infection-induced autoimmune response that targets the bile ducts. Cytomegalovirus (CMV) remains the most common virus being linked to BA. This meta-analysis aimed to estimate to what extent CMV infection is detected in patients with BA.

Methods  This study was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The databases of MEDLINE, Embase, Scopus, WHO-Virtual Health Library (VHL), ScienceDirect, and Google Scholar were used for the systematic search. The risk of bias was assessed using the Newcastle–Ottawa scale. Random effects model was used to estimate the pooled prevalence estimate with the corresponding 95% confidence interval (CI) using Comprehensive Meta-Analysis Software version 3.3.

Results  A total of 19 studies that fulfilled the eligibility criteria were included in the meta-analysis. The total number of infants with BA was 630 patients, and the pooled overall prevalence of CMV infection among them was 25.4% (95% CI: 15.9%–38.0%). There was high heterogeneity among studies (I ²  = 85.1%, p  < .001), and subgroup analyses showed significant regional differences (X ²  = 48.9, p <.001). Data on the prognosis of CMV-associated BA were scarce and obtainable from few studies that suggested an association between detection of CMV infection and poor prognosis of BA.

Conclusions  The limited available data demonstrates that the rate of detection of CMV infection is high in infants with BA. There is still a need for large studies with appropriate controls for obtaining more reliable results about the various aspects of the association between CMV infection and BA.

Hyperbilirubinemia in pediatrics: Evaluation and care

Hyperbilirubinemia is a common laboratory finding for children, especially in infancy. It represents a broad range of diagnoses from benign physiologic changes to severe systemic illness. This paper addresses the evaluation and differential diagnosis of hyperbilirubinemia for infants and older children based on the most recent guidelines published by the American Academy of Pediatrics (AAP) (1), the North American Society for Pediatric Gastroenterology, Hepatology, and Nutrition (NASPGHAN) and the European Society for Pediatric Gastroenterology, Hepatology and Nutrition (ESPGHAN) (2).

Gut Microbiota Dysbiosis Associated with Bile Acid Metabolism in Neonatal Cholestasis Disease

Neonatal cholestasis disease (NCD) is a complex and easily mis-diagnosed condition. We analyzed microbiota community structure in feces and measured short-chain fatty acids, bile acids (BAs) and liver function of 12 healthy, 13 NCD, and 13 treated infants after diagnosis. Based on 16S rRNA gene amplicon sequencing and gas-chromatographic-mass-spectrometric analysis of secondary BAs, we identified microbial genera and metabolites that associate with abnormal bile secretion. Streptococcus gallolyticus and Parabacteroides distasonis, and Lactobacillus gasseri had higher relative abundance in healthy and NCD infants respectively. Compared to NCD patients, healthy infants had higher LCA, CDCA and GCDCA fecal concentrations. The three microbial species and three secondary bile acids were selected as potential non-invasive combined biomarkers to diagnose NCD. We propose that microbiota-metabolite combined biomarkers could be used for diagnosis of NCD, and this may contribute to improved early clinical diagnosis of NCD in the future.

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.

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.

Rotavirus Reassortant-Induced Murine Model of Liver Fibrosis Parallels Human Biliary Atresia

BACKGROUND AND AIMS

Biliary atresia (BA) is a devastating neonatal cholangiopathy that progresses to fibrosis and end-stage liver disease by 2 years of age. Portoenterostomy may reestablish biliary drainage, but, despite drainage, virtually all afflicted patients develop fibrosis and progress to end-stage liver disease requiring liver transplantation for survival.

APPROACH AND RESULTS

In the murine model of BA, rhesus rotavirus (RRV) infection of newborn pups results in a cholangiopathy paralleling human BA and has been used to study mechanistic aspects of the disease. Unfortunately, nearly all RRV-infected pups succumb by day of life 14. Thus, in this study we generated an RRV-TUCH rotavirus reassortant (designated as T^R(VP2,VP4) ) that when injected into newborn mice causes an obstructive jaundice phenotype with lower mortality rates. Of the mice that survived, 63% developed Ishak stage 3-5 fibrosis with histopathological signs of inflammation/fibrosis and bile duct obstruction.

CONCLUSIONS

This model of rotavirus-induced neonatal fibrosis will provide an opportunity to study disease pathogenesis and has potential to be used in preclinical studies with an objective to identify therapeutic targets that may alter the course of BA.

Nationwide population-based study showed that the rotavirus vaccination had no impact on the incidence of biliary atresia in Korea

AIM

Rotaviruses have been associated with biliary atresia. This study investigated whether the rotavirus vaccine, which was introduced to Korea in 2008, had an impact on the incidence of biliary atresia.

METHODS

We identified all rotavirus infections (n = 436 826) and biliary atresia cases (n = 528) diagnosed from 2006 to 2015 from insurance and health databases. The annual and seasonal incidence of biliary atresia and rotavirus infection rates in neonates and children were calculated. The difference in the risk of biliary atresia between rotavirus-infected and non-infected neonates was analysed.

RESULTS

The incidence of rotavirus infections was 20.6 versus 13.4 per 1000 cases before (2006-2008) and after (2009-2015) vaccine implementation. However, neonatal rotavirus infection rates did not decrease, with an incidence of 14.5 versus 14.8 per 1000 cases before and after vaccination. The biliary atresia incidence remained constant at 12.0 per 100 000 cases. Rotavirus infections in neonates were a risk factor for biliary atresia (odds ratio 3.14, 95% confidence interval 1.87-5.26).

CONCLUSION

Rotavirus vaccination had no impact on the incidence of biliary atresia, possibly because the vaccination did not change the neonatal rotavirus infection rate through herd immunity. However, rotavirus infections in neonates were significantly associated with biliary atresia.

Unexpected Infant Death Due to Undiagnosed Biliary Atresia: A Case of Fatal Neglect

Biliary atresia (BA) is a fatal condition resulting in the lack of effective biliary drainage leading invariably to liver failure and cirrhosis within a year, and it is often lethal within a few months in the absence of corrective surgery or liver transplantation. In fact, BA is the most common indication for pediatric liver transplantation.Herein, we present a rare case of unexpected infant death due to BA diagnosed only postmortem in a context of child neglect and carelessness on the part of the parents. It emerged from the clinical history that after a few months, the parents no longer took their daughter to any medical checkups despite the indications and express recommendations for follow-up. The autopsy revealed agenesis of the gallbladder with BA and complete disruption of the hepatic architecture and parenchyma from biliary cirrhosis. Histological examinations documented severe biliary cirrhosis from hypoplasia of the biliary ducts.The child neglect in this case proved fatal inasmuch as an early diagnosis by a pediatrician would have likely allowed appropriate surgical treatment, thus avoiding the untimely death of the child. We highlight the importance of educating and informing parents (especially the disadvantaged) in matters of health. At the same time, primary care physicians should closely monitor the conditions and development of infants so as to recognize the early warning signs and symptoms of BA, bearing in mind that a timely diagnosis and proper surgical treatment can save the lives of most of these children.

Paediatric liver ultrasound: a pictorial essay

Ultrasound scan is a painless and radiation-free imaging modality and, therefore, it is widely considered the first-choice diagnostic tool in the setting of hepatopathies in paediatric patients. This article focuses on the normal ultrasound anatomy of the liver in neonatal and paediatric age and reviews the ultrasound appearance of the most common diffuse and focal liver affections.

Ultrasound findings in paediatric cholestasis: how to image the patient and what to look for

Paediatric biliary tract and gallbladder diseases include a variety of entities with a wide range of clinical presentations. Cholestasis represents an impaired secretion of bilirubin by hepatocytes, manifesting with high blood levels of conjugated bilirubin and jaundice. Various causes may be involved, which can be recognised analysing blood tests and hepatobiliary imaging, while sometimes liver biopsy or surgery may be necessary. High-resolution real-time ultrasonography is an important tool for differentiation of obstructive and non-obstructive causes of jaundice in infants and children. In this paper, we briefly review the normal anatomy and the ultrasound aspects of main pathologies affecting gallbladder and biliary tree in neonatal and paediatric age.

Antifibrotic potential of bone marrow‑derived mesenchymal stem cells in biliary atresia mice

Biliary atresia (BA) is a rare and severe disease that affects infants where a fibroinflammatory process destroys the bile ducts, leading to fibrosis and biliary cirrhosis, and mortality if untreated. Bone marrow‑derived mesenchymal stem cells (BMMSCs) have been considered as a promising therapy in fibrotic diseases. The aim of the present was to investigate the anti‑fibrotic roles of BMMSC transplantation in a BA mouse model. Mouse BA models were established by Rhesus rotavirus administration to neonatal mice. The results revealed that the liver enzyme and bilirubin metabolism levels, and the levels of the oxidative stress marker malondialdehyde (MDA) and the fibrosis marker were all increased in the BA model, while the liver tissue levels of superoxide dismutase and glutathione peroxidase were reduced. The hematoxylin and eosin and Masson's trichrome staining revealed severe liver fibrosis and collagen accumulation in BA livers. However, these indicators were all reversed once the BA mice were administered the BMMSC inoculation. In conclusion, the present study demonstrated the anti‑fibrotic potential of BMMSCs in BA mice, which may provide a novel approach to ameliorate the fibrotic response in BA patients.

Analysis of risk factors for morbidity in children undergoing the Kasai procedure for biliary atresia

OBJECTIVE

To evaluate the perioperative risk factors for 30-day complications of the Kasai procedure in a large, cross-institutional, modern dataset.

STUDY DESIGN

The 2012-2015 National Surgical Quality Improvement Program Pediatric database was used to identify patients undergoing the Kasai procedure. Patients' characteristics were compared by perioperative blood transfusions and 30-day outcomes, including complications, reoperations, and readmissions. Multivariable logistic regression was used to identify risk factors predictive of outcomes. Propensity matching was performed for perioperative blood transfusions to evaluate its effect on outcomes.

RESULTS

190 children were included with average age of 62 days. Major cardiac risk factors were seen in 6.3%. Perioperative blood transfusions occurred in 32.1%. The 30-day post-operative complication rate was 15.8%, reoperation 6.8%, and readmission 15.3%. After multivariate analysis, perioperative blood transfusions (OR 3.94; p < 0.01) and major cardiac risk factors (OR 7.82; p < 0.01) were found to increase the risk of a complication. Perioperative blood transfusion (OR 4.71; p = 0.01) was associated with an increased risk of reoperation. Readmission risk was increased by prematurity (OR 3.88; p = 0.04) and 30-day complication event (OR 4.09; p = 0.01). After propensity matching, perioperative blood transfusion was associated with an increase in complications (p < 0.01) and length of stay (p < 0.01).

CONCLUSION

Major cardiac risk factors and perioperative blood transfusions increase the risk of post-operative complications in children undergoing the Kasai procedure. Further research is warranted in the perioperative use of blood transfusions in this population.

LEVEL OF EVIDENCE

IV.

Hepatic autotaxin overexpression in infants with biliary atresia

Background

Autotaxin (ATX) is a secreted glycoprotein that is involved in the development of hepatic fibrogenesis via the enzymatic production of lysophosphatidic acid. The aim of this study was to investigate hepatic expression of ATX in biliary atresia (BA) compared with non-BA liver controls and to examine the association between ATX expression and clinical outcome in BA.

Methods

Liver specimens from BA infants (n = 20) were compared with samples from infants who underwent liver biopsy for reasons other than BA (n = 14) and served as controls. Relative mRNA and protein expression of ATX were quantified using real-time polymerase chain reaction (PCR) and immunohistochemistry. Masson’s Trichrome staining was performed to determine the degree of liver fibrosis.

Results

Quantitative real-time PCR demonstrated overexpression of ATX mRNA in BA livers. In immunohistochemical evaluation, ATX was positively stained on the hepatic parenchyma and the biliary epithelium in BA patients, as compared to non-BA controls. The immunostaining score of ATX in BA livers was also significantly higher than that observed in non-BA livers (P < 0.001). Subgroup analysis revealed that ATX expression in the patients with poor outcomes was significantly greater than in those with good outcomes (P = 0.03). Additionally, there was a positive correlation between hepatic ATX expression and Metavir fibrosis stage in BA livers (r = 0.79, P < 0.001).

Discussion

This study found that mRNA and protein expression of ATX were increased in BA livers. High hepatic ATX expression at the time of Kasai operation was associated with liver fibrosis and outcome in BA, suggesting that ATX may serve a role as a promising biomarker of the prognosis in biliary atresia.

Intrahepatic bile duct primary cilia in biliary atresia

AIM

The etiopathogenesis of non-syndromic biliary atresia (BA) is obscure. The primary aim was to investigate intrahepatic bile duct cilia (IHBC) in BA at diagnosis and its correlation with clinical outcome. The secondary aim was to analyze IHBC in routine paraffin-embedded liver biopsies using conventional scanning electron microscopy (SEM).

METHODS

Surgical liver biopsies taken at diagnosis from 22 BA infants (age range, 39-116 days) and from eight children with non-BA chronic cholestasis (age range, 162 days -16.8 years) were evaluated for IHBC by immunofluorescence (IF) and SEM. A minimum 18-month follow-up after surgery was available for all patients.

RESULTS

By IF, cilia were present in 6/8 (75%) non-BA but only in 3/22 (14%) BA cases, and cilia were reduced or absent in 19/22 (86%) BA and 2/8 (25%) non-BA livers (P < 0.01). In BA, cilia presence was found to be associated with clearance of jaundice at 6-month follow-up (P < 0.05). However, high overall survival rates with native liver, >90% at 12 months, and >70% at 24 months post-surgery, were recorded regardless of cilia presence/absence at diagnosis. Electron microscopy was able to detect bile ducts and cilia in routine liver biopsies, revealing significant abnormalities in 100% BA livers.

CONCLUSIONS

The presence of IHBC in BA livers at the diagnosis was associated with resolution of cholestasis, although was not predictive of short-term survival with native liver. Scanning electron microscopy represents a powerful new tool to study routine liver biopsies in biliary disorders. Cilia dysfunction in BA pathogenesis and/or disease progression warrants further investigation.

Cxcr2 signaling and the microbiome suppress inflammation, bile duct injury, and the phenotype of experimental biliary atresia

Biliary atresia is progressive fibro-inflammatory cholangiopathy of young children. Central to pathogenic mechanisms of injury is the tissue targeting by the innate and adaptive immune cells. Among these cells, neutrophils and the IL-8/Cxcl-8 signaling via its Cxcr2 receptor have been linked to bile duct injury. Here, we aimed to investigate whether the intestinal microbiome modulates Cxcr2-dependent bile duct injury and obstruction. Adult wild-type (WT) and Cxcr2^-/- mice were fed a diet supplemented with sulfamethoxazole/trimethoprim (SMZ/TMP) during pregnancy and lactation, and their pups were injected intraperitoneally with rhesus rotavirus (RRV) within 24 hours of life to induce experimental biliary atresia. The maternal exposure to SMZ/TMP significantly lowered the incidence of jaundice and bile duct obstruction and resulted in improved survival, especially in Cxcr2^-/- mice. Analyses of the microbiome by deep sequencing of 16S rRNA of the neonatal colon showed a delay in bacterial colonization of WT mice induced by SMZ/TMP, with a notable switch from Proteobacteria to Firmicutes. Interestingly, the genetic inactivation of Cxcr2 alone produced a similar bacterial shift. When treated with SMZ/TMP, Cxcr2^-/- mice infected with RRV to induce experimental biliary atresia showed further enrichment of Corynebacterium, Anaerococcus and Streptococcus. Among these, Anaerococcus lactolyticus was significantly associated with a suppression of biliary injury, cholestasis, and survivability. These results suggest that the postnatal development of the intestinal microbiota is an important susceptibility factor for experimental biliary atresia.

A Point Mutation in the Rhesus Rotavirus VP4 Protein Generated through a Rotavirus Reverse Genetics System Attenuates Biliary Atresia in the Murine Model

Rotavirus infection is one of the most common causes of diarrheal illness in humans. In neonatal mice, rhesus rotavirus (RRV) can induce biliary atresia (BA), a disease resulting in inflammatory obstruction of the extrahepatic biliary tract and intrahepatic bile ducts. We previously showed that the amino acid arginine (R) within the sequence SRL (amino acids 445 to 447) in the RRV VP4 protein is required for viral binding and entry into biliary epithelial cells. To determine if this single amino acid (R) influences the pathogenicity of the virus, we generated a recombinant virus with a single amino acid mutation at this site through a reverse genetics system. We demonstrated that the RRV mutant (RRV^VP4-R446G) produced less symptomatology and replicated to lower titers both in vivo and in vitro than those seen with wild-type RRV, with reduced binding in cholangiocytes. Our results demonstrate that a single amino acid change in the RRV VP4 gene influences cholangiocyte tropism and reduces pathogenicity in mice.IMPORTANCE Rotavirus is the leading cause of diarrhea in humans. Rhesus rotavirus (RRV) can also lead to biliary atresia (a neonatal human disease) in mice. We developed a reverse genetics system to create a mutant of RRV (RRV^VP4-R446G) with a single amino acid change in the VP4 protein compared to that of wild-type RRV. In vitro, the mutant virus had reduced binding and infectivity in cholangiocytes. In vivo, it produced fewer symptoms and lower mortality in neonatal mice, resulting in an attenuated form of biliary atresia.

Neonatal Cholestasis

Neonatal jaundice is common and usually not concerning when it is secondary to unconjugated hyperbilirubinemia, below the neurotoxic level, and resolves early. Primary care providers should be vigilant, however, about evaluating infants in whom jaundice presents early, is prolonged beyond 2 weeks of life, or presents at high levels. Even in well-appearing infants, fractionated (direct and indirect) bilirubin levels should be obtained in these clinical scenarios to evaluate for potential cholestasis. This review presents an approach to the evaluation of a jaundiced infant and discusses diagnosis and management of several causes of neonatal cholestasis.

The SRL peptide of rhesus rotavirus VP4 protein governs cholangiocyte infection and the murine model of biliary atresia

Biliary atresia (BA) is a neonatal obstructive cholangiopathy that progresses to end-stage liver disease, often requiring transplantation. The murine model of BA, employing rhesus rotavirus (RRV), parallels human disease and has been used to elucidate mechanistic aspects of a virus induced biliary cholangiopathy. We previously reported that the RRV VP4 gene plays an integral role in activating the immune system and induction of BA. Using rotavirus binding and blocking assays, this study elucidated how RRV VP4 protein governs cholangiocyte susceptibility to infection both in vitro and in vivo in the murine model of BA. We identified the amino acid sequence on VP4 and its cholangiocyte binding protein, finding that the sequence is specific to those rotavirus strains that cause obstructive cholangiopathy. Pretreatment of murine and human cholangiocytes with this VP4-derived peptide (TRTRVSRLY) significantly reduced the ability of RRV to bind and infect cells. However, the peptide did not block cholangiocyte binding of TUCH and Ro1845, strains that do not induce murine BA. The SRL sequence within TRTRVSRLY is required for cholangiocyte binding and viral replication. The cholangiocyte membrane protein bound by SRL was found to be Hsc70. Inhibition of Hsc70 by small interfering RNAs reduced RRV's ability to infect cholangiocytes. This virus-cholangiocyte interaction is also seen in vivo in the murine model of BA, where inoculation of mice with TRTRVSRLY peptide significantly reduced symptoms and mortality in RRV-injected mice.

CONCLUSION

The tripeptide SRL on RRV VP4 binds to the cholangiocyte membrane protein Hsc70, defining a novel binding site governing VP4 attachment. Investigations are underway to determine the cellular response to this interaction to understand how it contributes to the pathogenesis of BA. (Hepatology 2017;65:1278-1292).

Guideline for the Evaluation of Cholestatic Jaundice in Infants: Joint Recommendations of the North American Society for Pediatric Gastroenterology, Hepatology, and Nutrition and the European Society for Pediatric Gastroenterology, Hepatology, and Nutrition

Cholestatic jaundice in infancy affects approximately 1 in every 2500 term infants and is infrequently recognized by primary providers in the setting of physiologic jaundice. Cholestatic jaundice is always pathologic and indicates hepatobiliary dysfunction. Early detection by the primary care physician and timely referrals to the pediatric gastroenterologist/hepatologist are important contributors to optimal treatment and prognosis. The most common causes of cholestatic jaundice in the first months of life are biliary atresia (25%-40%) followed by an expanding list of monogenic disorders (25%), along with many unknown or multifactorial (eg, parenteral nutrition-related) causes, each of which may have time-sensitive and distinct treatment plans. Thus, these guidelines can have an essential role for the evaluation of neonatal cholestasis to optimize care. The recommendations from this clinical practice guideline are based upon review and analysis of published literature and the combined experience of the authors. The committee recommends that any infant noted to be jaundiced after 2 weeks of age be evaluated for cholestasis with measurement of total and direct serum bilirubin, and that an elevated serum direct bilirubin level (direct bilirubin levels >1.0 mg/dL or >17 μmol/L) warrants timely consideration for evaluation and referral to a pediatric gastroenterologist or hepatologist. Of note, current differential diagnostic plans now incorporate consideration of modern broad-based next-generation DNA sequencing technologies in the proper clinical context. These recommendations are a general guideline and are not intended as a substitute for clinical judgment or as a protocol for the care of all infants with cholestasis. Broad implementation of these recommendations is expected to reduce the time to the diagnosis of pediatric liver diseases, including biliary atresia, leading to improved outcomes.

A 10-Year united network for organ sharing review of mortality and risk factors in young children awaiting liver transplantation

Young children < 2 years of age with chronic end-stage liver disease (YC2) are a uniquely vulnerable group listed for liver transplantation, characterized by a predominance of biliary atresia (BA). To investigate wait-list mortality, associated risk factors, and outcomes of YC2, we evaluated United Network for Organ Sharing registry data from April 2003 to March 2013 for YC2 listed for deceased donor transplant (BA = 994; other chronic liver disease [CLD] = 221). Overall, wait-list mortality among YC2 was 12.4% and posttransplant mortality was 8%, accounting for an overall postlisting mortality of 19.6%. YC2 demonstrated 12.2%, 18.7%, and 20.6% wait-list mortality by 90, 180, and 270 days, respectively. YC2 with CLD demonstrated significantly higher wait-list mortality compared with BA among YC2 (23.9% versus 9.8%; P < 0.05). Multivariate analyses revealed that listing Pediatric End-Stage Liver Disease [PELD] > 21 (hazard ratio [HR], 3.2; 95% confidence interval [CI], 1.6-6.5), lack of exception (HR, 5.8; 95% CI, 2.8-11.8), listing height < 60.6 cm (HR, 2.1; 95% CI, 1.4-3.1), listing weight  > 10 kg (HR, 3.8; 95% CI, 1.5-9.2), and initial creatinine > 0.5 (HR, 6.8; 95% CI, 3.4-13.5) were independent risk factors for YC2 wait-list mortality (P < 0.005 for all). Adjusting for all variables, the risk of death among CLD patients was 2 (95% CI, 1.3-3.1) times greater than patients with BA + surgery (presumed Kasai). Furthermore, the risk of death in BA without surgery was 1.9 (95% CI, 1‐3.4) times greater than BA with presumed Kasai. Our data highlight unacceptably high wait-list and early post-liver transplant mortality in YC2 not predicted by PELD and suggest key risk factors deserving of further study in this age group. Liver Transplantation 22 1584-1592 2016 AASLD.

Rhesus rotavirus VP6 regulates ERK-dependent calcium influx in cholangiocytes

The Rhesus rotavirus (RRV) induced murine model of biliary atresia (BA) is a useful tool in studying the pathogenesis of this neonatal biliary obstructive disease. In this model, the mitogen associated protein kinase pathway is involved in RRV infection of biliary epithelial cells (cholangiocytes). We hypothesized that extracellular signal-related kinase (ERK) phosphorylation is integral to calcium influx, allowing for viral replication within the cholangiocyte. Utilizing ERK and calcium inhibitors in immortalized cholangiocytes and BALB/c pups, we determined that ERK inhibition resulted in reduced viral yield and subsequent decreased symptomatology in mice. In vitro, the RRV VP6 protein induced ERK phosphorylation, leading to cellular calcium influx. Pre-treatment with an ERK inhibitor or Verapamil resulted in lower viral yields. We conclude that the pathogenesis of RRV-induced murine BA is dependent on the VP6 protein causing ERK phosphorylation and triggering calcium influx allowing replication in cholangiocytes.

The toxin biliatresone causes mouse extrahepatic cholangiocyte damage and fibrosis through decreased glutathione and SOX17

Biliary atresia, the most common indication for pediatric liver transplantation, is a fibrotic disease of unknown etiology affecting the extrahepatic bile ducts of newborns. The recently described toxin biliatresone causes lumen obstruction in mouse cholangiocyte spheroids and represents a new model of biliary atresia. The goal of this study was to determine the cellular changes caused by biliatresone in mammalian cells that ultimately lead to biliary atresia and extrahepatic fibrosis. We treated mouse cholangiocytes in three-dimensional (3D) spheroid culture and neonatal extrahepatic duct explants with biliatresone and compounds that regulate glutathione (GSH). We examined the effects of biliatresone on SOX17 levels and determined the effects of Sox17 knockdown on cholangiocytes in 3D culture. We found that biliatresone caused disruption of cholangiocyte apical polarity and loss of monolayer integrity. Spheroids treated with biliatresone had increased permeability as shown by rhodamine efflux within 5 hours compared with untreated spheroids, which retained rhodamine for longer than 12 hours. Neonatal bile duct explants treated with the toxin showed lumen obstruction with increased subepithelial staining for α-smooth muscle actin and collagen, consistent with fibrosis. Biliatresone caused a rapid and transient decrease in GSH, which was both necessary and sufficient to mediate its effects in cholangiocyte spheroid and bile duct explant systems. It also caused a significant decrease in cholangiocyte levels of SOX17, and Sox17 knockdown in cholangiocyte spheroids mimicked the effects of biliatresone.

CONCLUSION

Biliatresone decreases GSH and SOX17 in mouse cholangiocytes. In 3D cell systems, this leads to cholangiocyte monolayer damage and increased permeability; in extrahepatic bile duct explants, it leads to disruption of the extrahepatic biliary tree and subepithelial fibrosis. This mechanism may be important in understanding human biliary atresia. (Hepatology 2016;64:880-893).

Glutathione antioxidant pathway activity and reserve determine toxicity and specificity of the biliary toxin biliatresone in zebrafish

Biliatresone is an electrophilic isoflavone isolated from Dysphania species plants that has been causatively linked to naturally occurring outbreaks of a biliary atresia (BA)-like disease in livestock. Biliatresone has selective toxicity for extrahepatic cholangiocytes (EHCs) in zebrafish larvae. To better understand its mechanism of toxicity, we performed transcriptional profiling of liver cells isolated from zebrafish larvae at the earliest stage of biliatresone-mediated biliary injury, with subsequent comparison of biliary and hepatocyte gene expression profiles. Transcripts encoded by genes involved in redox stress response, particularly those involved in glutathione (GSH) metabolism, were among the most prominently up-regulated in both cholangiocytes and hepatocytes of biliatresone-treated larvae. Consistent with these findings, hepatic GSH was depleted at the onset of biliary injury, and in situ mapping of the hepatic GSH redox potential using a redox-sensitive green fluorescent protein biosensor showed that it was significantly more oxidized in EHCs both before and after treatment with biliatresone. Pharmacological and genetic manipulation of GSH redox homeostasis confirmed the importance of GSH in modulating biliatresone-induced injury given that GSH depletion sensitized both EHCs and the otherwise resistant intrahepatic cholangiocytes to the toxin, whereas replenishing GSH level by N-acetylcysteine administration or activation of nuclear factor erythroid 2-like 2 (Nrf2), a transcriptional regulator of GSH synthesis, inhibited EHC injury.

CONCLUSION

These findings strongly support redox stress as a critical contributing factor in biliatresone-induced cholangiocyte injury, and suggest that variations in intrinsic stress responses underlie the susceptibility profile. Insufficient antioxidant capacity of EHCs may be critical to early pathogenesis of human BA. (Hepatology 2016;64:894-907).

Identification of a plant isoflavonoid that causes biliary atresia

Biliary atresia (BA) is a rapidly progressive and destructive fibrotic disorder of unknown etiology affecting the extrahepatic biliary tree of neonates. Epidemiological studies suggest that an environmental factor, such as a virus or toxin, is the cause of the disease, although none have been definitively established. Several naturally occurring outbreaks of BA in Australian livestock have been associated with the ingestion of unusual plants by pregnant animals during drought conditions. We used a biliary secretion assay in zebrafish to isolate a previously undescribed isoflavonoid, biliatresone, from Dysphania species implicated in a recent BA outbreak. This compound caused selective destruction of the extrahepatic, but not intrahepatic, biliary system of larval zebrafish. A mutation that enhanced biliatresone toxicity mapped to a region of the zebrafish genome that has conserved synteny with an established human BA susceptibility locus. The toxin also caused loss of cilia in neonatal mouse extrahepatic cholangiocytes in culture and disrupted cell polarity and monolayer integrity in cholangiocyte spheroids. Together, these findings provide direct evidence that BA could be initiated by perinatal exposure to an environmental toxin.

Rhesus rotavirus VP4 sequence-specific activation of mononuclear cells is associated with cholangiopathy in murine biliary atresia

Biliary atresia (BA), a neonatal obstructive cholangiopathy, remains the most common indication for pediatric liver transplantation in the United States. In the murine model of BA, Rhesus rotavirus (RRV) VP4 surface protein determines biliary duct tropism. In this study, we investigated how VP4 governs induction of murine BA. Newborn mice were injected with 16 strains of rotavirus and observed for clinical symptoms of BA and mortality. Cholangiograms were performed to confirm bile duct obstruction. Livers and bile ducts were harvested 7 days postinfection for virus titers and histology. Flow cytometry assessed mononuclear cell activation in harvested cell populations from the liver. Cytotoxic NK cell activity was determined by the ability of NK cells to kill noninfected cholangiocytes. Of the 16 strains investigated, the 6 with the highest homology to the RRV VP4 (>87%) were capable of infecting bile ducts in vivo. Although the strain Ro1845 replicated to a titer similar to RRV in vivo, it caused no symptoms or mortality. A Ro1845 reassortant containing the RRV VP4 induced all BA symptoms, with a mortality rate of 89%. Flow cytometry revealed that NK cell activation was significantly increased in the disease-inducing strains and these NK cells demonstrated a significantly higher percentage of cytotoxicity against noninfected cholangiocytes. Rotavirus strains with >87% homology to RRV's VP4 were capable of infecting murine bile ducts in vivo. Development of murine BA was mediated by RRV VP4-specific activation of mononuclear cells, independent of viral titers.

What Causes Biliary Atresia? Unique Aspects of the Neonatal Immune System Provide Clues to Disease Pathogenesis

Biliary atresia (BA) is the most frequent identifiable cause of neonatal cholestasis and the majority of patients will need liver transplantation for survival. Despite surgical intervention with the Kasai portoenterostomy, significant fibrosis and cirrhosis develops early in life. An increased understanding of what causes this inflammatory fibrosing cholangiopathy will lead to therapies aimed at protecting the intrahepatic biliary system from immune-mediated damage. This review focuses on studies pertaining to the role of the adaptive immune response in bile duct injury in BA, including cellular and humoral immunity. The neonatal presentation of BA begs the question of what are potential modifications of unique aspects of the neonatal immune system that "sets the stage" for the progressive biliary disease? Throughout this article, characteristics of the neonatal immune response are outlined and theories as to how alterations of this response could contribute to the pathogenesis of BA are discussed. These include aberrant Th1 and Th17 responses, deficiencies in regulatory T cells, activation of humoral immunity and autoimmunity. In order to advance our understanding of the etiology of BA, future studies should focus on those unique aspects of the neonatal immune system that have gone awry, as detailed throughout this review.

MicroRNAs and benign biliary tract diseases

Cholangiocytes, the epithelial cells lining the biliary tree, represent only a small portion of the total liver cell population (3-5%), but they are responsible for the secretion of up to 40% of total daily bile volume. In addition, cholangiocytes are the target of a diverse group of liver diseases affecting the biliary tract, the cholangiopathies; for most of these conditions, the pathological mechanisms are unclear. MicroRNAs (miRNAs) are small, noncoding RNAs that posttranscriptionally regulate gene expression. Thus, it is not surprising that altered miRNA profiles underlie the dysregulation of several proteins involved in the pathobiology of the cholangiopathies, as well as showing promise as diagnostic and prognostic tools. Here the authors review recent work relevant to the role of miRNAs in the etiopathogenesis of several of the cholangiopathies (i.e., fibroinflammatory cholangiopathies and polycystic liver diseases), discuss their value as prognostic and diagnostic tools, and provide suggestions for further research.

Genetic contributors and modifiers of biliary atresia

To date, the etiology and pathogenic underpinning of the progression of the most prevalent serious neonatal liver disease, biliary atresia, remains elusive. This disease presents as an aggressive form of neonatal cholestasis characterized by the destruction and obliteration of the extrahepatic bile ducts within the first few weeks of life and a rapid progression of biliary fibrosis, likely due to unremitting cholestasis and retention of biliary constituents including bile acids. In ∼5% of patients, biliary atresia is associated with laterality features, suggesting a genetic underpinning to a disease that begins soon after birth. However, biliary atresia does not occur within families and twins are discordant, indicating an absence of strict mendelian inheritance. Despite this, genes related to bile duct dysmorphogenesis/ciliopathies overlapping with features of biliary atresia in both humans and nonhuman model systems have been proposed. Taken together, strict genetic etiologies leading to a common pathway of a neonatal cholangiopathy resulting in biliary atresia remain elusive. Contributions from fibrogenesis- and inflammation-based studies suggest that early engagement of these pathways contributes to disease progression, but a recent double-blind study did not suggest any benefit from early use of corticosteroids. However, there are genetic contributions to the adaptation and response to cholangiopathies and cholestasis that may be present in certain populations that likely impact upon the response to hepatoportoenterostomy and subsequent biliary tract function. Studies utilizing next generation sequencing technologies (e.g., exome analysis) are ongoing in several laboratories around the world; they are expected to provide insights into genetic contributions to biliary atresia outcomes. Altogether, combinations of exome sequencing and large population studies are expected to reveal causative and modifying genes relevant to patients with biliary atresia as a means to provide therapeutic targets and potential opportunities for genetic screening.

MicroRNAs in Cholangiopathies

Cholangiocytes, the cells lining bile ducts, comprise a small fraction of the total cellular component of the liver, yet perform the essential role of bile modification and transport of biliary and blood constituents. Cholangiopathies are a diverse group of biliary disorders with the cholangiocyte as the target cell; the etiopathogenesis of most cholangiopathies remains obscure. MicroRNAs are small non-coding RNAs that post-transcriptionally regulate gene expression. These small RNAs may not only be involved in the etiopathogenesis of disease, but are showing promise as diagnostic and prognostic tools. In this brief review, we summarize recent work regarding the role of microRNAs in the etiopathogenesis of several cholangiopathies, and discuss their utility as prognostic and diagnostic tools.

Overexpression of LDOC1 in human biliary epithelial cells inhibits apoptosis through NF-κB signaling

OBJECTIVES

Biliary atresia (BA) is a devastating pediatric cholestatic liver disease. Increasing evidence indicates that nuclear factor (NF)-κB signaling plays a key role in the pathogenesis of BA. Leucine zipper downregulated in cancer 1 (LDOC1) may control the expression of NF-κB. The aim of this study was to evaluate the relation between LDOC1 and inflammation/apoptosis mediated by NF-κB in the human intrahepatic biliary epithelial cells (HIBECs).

METHODS

HIBECs were divided into 3 treatment groups: control, mock transfection group, and LDOC1 transfection. Immunofluorescence, reverse transcription polymerase chain reaction, Western blot, and flow cytometry analysis were used to investigate the effectiveness of LDOC1-transfected HIBECs and the expression of NF-κB. Apoptosis was detected by Hochest/ propidium iodide staining. Interleukin (IL)-2 and tumor necrosis factor (TNF)-α levels were evaluated by enzyme-linked immunosorbent assay.

RESULTS

The expression of NF-κB was higher in the LDOC1-transfected group when compared with the control and mock-transfected groups as evaluated by immunofluorescence, reverese transcription polymerase chain reaction, and Western blot analysis. The rate of apoptosis was significantly lower in the LDOC1-transfected group when compared with the control and mock-transfected groups. The levels of IL-2 and TNF-α were significantly higher in the LDOC1-transfected group when compared with the control and mock-transfected groups.

CONCLUSIONS

Upregulation of LDOC1 in HIBEC increases the expression of NF-κB, which may promote the activation of IL-2 and TNF-α secretion and inhibit cell apoptosis.

Extrahepatic cholangiocyte cilia are abnormal in biliary atresia

OBJECTIVES

Biliary atresia (BA) is a rapidly progressive form of biliary fibrosis affecting neonates. We previously reported that primary cilia on the intrahepatic cholangiocytes of patients with both syndromic and nonsyndromic BA were structurally abnormal. Our objective was to determine whether extrahepatic cholangiocytes in human biliary atresia, intrahepatic and extrahepatic cholangiocytes of rhesus rotavirus (RRV)-infected neonatal mice, and RRV-infected primary neonatal extrahepatic cholangiocytes also demonstrate ciliary abnormalities.

METHODS

The livers of neonatal BALB/c mice injected with RRV that developed jaundice, human extrahepatic bile duct samples obtained at time of hepatoportoenterostomy, and RRV-infected primary neonatal cholangiocytes were stained with antibodies against acetylated α tubulin to identify primary cilia.

RESULTS

Extrahepatic cholangiocytes from RRV-treated mice demonstrated minimal loss of primary cilia at day 3 but almost complete loss at day 8 and partial loss at day 12. No changes were seen in mouse intrahepatic bile ducts at any of the time points. In the human BA samples, primary cilia were almost completely absent from extrahepatic duct cholangiocytes. There were, however, abundant cilia in the peribiliary glands adjacent to extrahepatic ducts in the BA sample. Cilia in RRV-infected primary neonatal cholangiocytes were significantly decreased compared with controls.

CONCLUSIONS

Primary cilia are selectively lost from neonatal extrahepatic but not intrahepatic cholangiocytes after RRV infection in BALB/c mice. The cilia are also decreased in RRV-infected primary cholangiocytes and the extrahepatic ducts from human patients with BA. This suggests that ciliary abnormalities are part of the pathophysiology of BA.

Role of myeloid differentiation factor 88 in Rhesus rotavirus-induced biliary atresia

BACKGROUND

Biliary atresia (BA) is a unique neonatal disease resulting from inflammatory and fibrosing obstruction of the extrahepatic biliary tree. Previous studies have demonstrated the critical role of innate immunity and the Th1 response to activated inflammatory cells and overexpressed cytokines in the pathogenesis of BA. Myeloid differentiation factor 88 (MyD88) is a critical adaptor molecule that has been shown to play a crucial role in immunity. We investigated the role of MyD88 in the inflammatory response and development of cholangiopathy in murine BA.

METHODS

MyD88 knockout (MyD88(-/-)) and wild-type (WT) BALB/c pups were injected with Rhesus rotavirus or saline on day 1 of life. The mice were monitored for clinical symptoms of BA, including jaundice, acholic stools, bilirubinuria, and death. The liver and extrahepatic bile ducts were harvested for histologic evaluation and the quantification of viral content, determination of cytokine expression, and detection of inflammatory cells.

RESULTS

Rhesus rotavirus infection produced symptoms in 100% of both MyD88(-/-) and WT pups, with survival of 18% of WT and 0% of MyD88(-/-) mice. Histologic analysis demonstrated bile duct obstruction in both MyD88(-/-) and WT mice. Viral titers obtained 7 d after infection and expression of interferon-γ and tumor necrosis factor-α at day 3, 5, 8, and 12 after infection revealed no significant differences between the WT and MyD88(-/-) mice. Flow cytometry demonstrated similar levels of activated CD8+ T cells and natural killer cells.

CONCLUSIONS

The pathogenesis of murine BA is independent of the MyD88 signaling inflammatory pathway, suggesting alternative mechanisms are crucial in the induction of the model.

Biliary atresia: cellular dynamics and immune dysregulation

The cause of biliary atresia is unknown; in the past few decades, the majority of investigations related to its pathogenesis have centered on viral infections and immunity. The acquired or perinatal form of biliary atresia entails a progressive inflammatory injury of bile ducts, leading to fibrosis and obliteration of both the extrahepatic and intrahepatic bile ducts. Theories of pathogenesis include viral infection, chronic inflammatory or autoimmune-mediated bile duct injury, and abnormalities in bile duct development. This review will focus solely on human studies pertaining to a potential viral trigger of bile duct injury at diagnosis and provide insight into the interplay of the innate and adaptive immune responses in the pathogenesis of disease.

MicroRNA profiling identifies miR-29 as a regulator of disease-associated pathways in experimental biliary atresia

Biliary atresia (BA) is a pediatric liver disease of unknown underlying etiology, in which fibroinflammatory destruction of the extrahepatic biliary system leads to obstructive cholestasis. MicroRNAs are a class of short (18-23 nucleotide), noncoding RNA molecules, which act as negative regulators of target mRNA stability and translation. The importance of these molecules in normal and diseased liver has been demonstrated, but their potential role in the pathogenesis of BA has not been addressed. We have profiled changes in liver microRNA levels in an established mouse model of the disease, identified significantly altered transcripts, and defined the spatial expression patterns of selected microRNAs. Two of these, miR-29a/29b1, are upregulated in experimental BA. Using antisense oligonucleotide-mediated inhibition in mice, we have delineated the full set of hepatic genes regulated by miR-29 and identified 2 mRNA targets of potential pathological relevance in experimental BA, Igf1 and Il1RAP. We have used reporter assays to confirm that Igf1 and Il1RAP are direct targets of miR-29.

Patients with biliary atresia have elevated direct/conjugated bilirubin levels shortly after birth

OBJECTIVES

Healthy infants are thought to acquire biliary atresia (BA) in the first weeks of life. Because those diagnosed earlier have better outcomes, we were interested in determining the earliest time BA could be detected. We started by examining the immediate postnatal period, hypothesizing that newborns would not yet have acquired disease and still have normal direct/conjugated bilirubin (DB/CB) levels.

PATIENTS AND METHODS

Newborn DB/CB levels were obtained retrospectively from birth hospitals. Subjects with BA were born between 2007 and 2010 and cared for at Texas Children's Hospital. Those with BA splenic malformation syndrome or born prematurely were excluded. Control subjects were term newborns who later never developed neonatal liver disease.

RESULTS

Of the 61 subjects with BA, 56% had newborn DB/CB levels measured. All DB/CB levels exceeded laboratory norms and rose over time. At 24 to 48 hours of life, subjects with BA had mean DB levels significantly higher than those of controls (1.4 ± 0.43 vs. 0.19 ± 0.075 mg/dL, P < .0001), even while their mean total bilirubin (TB) levels remained below phototherapy limits. Finally, despite the elevated DB/CB levels, the majority of patients (79%) had normal DB:TB ratios ≤ 0.2.

CONCLUSIONS

Patients with BA have elevated DB/CB levels shortly after birth. To detect affected infants earlier and improve outcomes, the results suggest two possibilities: (1) screen all newborns for elevated DB/CB levels, rather than just those who appear jaundiced; and then (2) follow all newborns with elevated DB/CB levels, rather than just those with DB:TB ratios >0.2.

The outcome of laparoscopic portoenterostomy for biliary atresia in children

AIM

There were only a few reports on laparoscopic portoenterostomy for biliary atresia in children. We report our experience on laparoscopic Kasai operation for biliary atresia.

MATERIAL AND METHODS

A retrospective review of all children who had biliary atresia underwent laparoscopic portoenterostomy from January 2002 to September 2006 were included and analyzed.

RESULTS

Sixteen children (five boys and eleven girls) with a mean age of 66 days (range 47-106 days) at operation were included in this study. All patients had type III biliary atresia. There was no conversion to open procedure. The operative time ranged from 193 to 435 min (mean 292 min). At a median follow-up of 72 months (range 33-89 months), eight patients were free of jaundice with bilirubin level <20 μmol/L and did not require liver transplantation. Seven patients underwent liver transplantation. One patient who had persistent elevated bilirubin defaulted follow-up. One patient complicated with volvulus of intestine post-operatively. All patients survived except one patient who had combined liver and intestine transplantation.

CONCLUSION

Laparoscopic portoenterostomy in children with biliary atresia is technically feasible. 50% of children who had type III biliary atresia were free of jaundice and did not require liver transplantation. A longer follow-up is required to assess the long-term outcome.

Ductal plate malformation-like arrays in early explants after a Kasai procedure are independent of splenic malformation complex (heterotaxy)

Biliary atresia has at least 2 proposed forms, the common perinatal and the less common embryonic subtype with earlier onset and/or extrahepatic developmental anomalies. Histologic evidence of ductal plate malformation (DPM)-like change in liver has been proposed both as a marker for the embryonic type and as a predictor of poor outcome after Kasai portoenterostomy. We investigated the prevalence of DPM-like change in liver explants in usual biliary atresia (BA) and in BA with splenic malformation syndrome (BASM). Liver sections from 8 patients with BA and 6 with BASM, all of whom had a Kasai procedure followed by explant before age 2 years, were analyzed using hematoxylin and eosin, trichrome, CK7, and AE1/AE3 stains. Each block was scored for inflammation and fibrosis. We estimated the number of portal areas per block and counted the number of definite and possible examples of DPM-like change, defined as a circumferential duct complex arranged around a fibrovascular core. We assessed whether the frequency per portal area was related to low and high scores for either inflammation or fibrosis. Definite and possible examples of DPM-like arrays were present in about 10% of portal areas in both patient groups, but these were unevenly distributed. There was no statistical difference between BA and BASM in terms of the number of examples per portal area. No correlation existed between degree of fibrosis and the intensity of portal inflammation and the number of DPM-like arrays. Ductal plate malformation-like arrays do not distinguish perinatal BA from BA associated with heterotaxy in liver explants after a failed Kasai procedure.

Integrin alphavbeta6 and mediators of extracellular matrix deposition are up-regulated in experimental biliary atresia

INTRODUCTION

Biliary atresia (BA) is a progressive obliteration of the extrahepatic bile ducts resulting in hepatic fibrosis. The underlying mechanisms have not been defined. We used an animal model of BA to evaluate mediators of extracellular matrix (ECM) processing to determine which factors may be involved.

METHODS

Newborn BALB/c mice received an intraperitoneal injection with rhesus rotavirus or saline within 24 h of birth. Livers were harvested on days 7 and 14 for histology and immunohistochemistry (IHC). RNA expression was determined using quantitative real-time PCR. Human liver from patients with BA and those having a resection for nonfibrosing diseases was also evaluated.

RESULTS

In experimental mice, mRNA expression for tissue inhibitor of metalloproteinase (TIMP)-1 and matrix metalloproteinase (MMP)-7 was increased 18-fold and 69-fold, respectively on day 7, with further increases on day 14. On day 14, mRNA expression for plasminogen activator inhibitor (PAI)-1 (38-fold), TIMP-4 (9.5-fold), and MMP-9 (5.5-fold) mRNA was also observed. Furthermore, integrin alpha(v) beta(6) mRNA expression was increased on days 7 (11-fold) and 14 (6-fold). Presence of integrin alpha(v) beta(6) protein was confirmed by IHC in both mouse and human specimens in the proliferating biliary epithelium.

CONCLUSIONS

Our data suggest experimental BA is associated with increased mRNA expression of ECM degradation inhibitors, TIMP-1, PAI-1, and TIMP-4. MMP-7 and MMP-9 expression is also elevated in this model. Furthermore, increased gene expression of integrin alpha(v)beta(6) was demonstrated and IHC confirmed protein expression. Integrin alpha(v)beta(6) or the inhibitors of ECM breakdown may be attractive targets for future treatment strategies.

Effect of interleukin-2 and tumor necrosis factor-alpha on osteopontin: molecular function and biological process

BACKGROUND

Biliary atresia (BA) is the most common cause of neonatal cholestasis. Recently it was reported that osteopontin (OPN) expression by human bile duct epithelial cells in culture was responsive to interleukin-2 (IL-2) and tumor necrosis factor-alpha (TNF-alpha). This might be an important part in the pathogenesis of BA, but the function of IL-2 and TNF-alpha in OPN expression is not well understood.

METHODS

A new gene ontology technology was used to predict the molecular function and biological process of the effect of IL-2 and TNF-alpha on OPN.

RESULTS

Using GoFigure server, the molecular function and biological process of the effect of IL-2 and TNF-alpha on OPN is predicted. Compared to IL-2, TNF-alpha and OPN, the IL-2-TNF-alpha-OPN combination has more functions.

CONCLUSION

The IL-2-TNF-alpha-OPN combination presents many more functions including positive regulation of osteoclast and response to virus. IL-2 and TNF have a synergistic effect on OPN expression.

Partial proximal 10q trisomy: a new case associated with biliary atresia

Herein we describe a unique case of partial proximal 10q trisomy presenting biliary atresia, anal anteposition and cardiac malformation. The 10q duplication was confirmed by G banding on prophase chromosomes. A review of the literature confirmed that the patient displayed characteristic dysmorphic features of the recently defined partial proximal trisomy 10q syndrome and emphasized the interindividual variability of visceral malformations.

Biliary atresia: interdisciplinary initiatives focus on a rare disease

During the last decade, biliary atresia (BA) has attained more interest and the frequency of BA-related publications has increased continuously. Pediatric hepatologists and pediatric surgeons are very active in improving diagnosis and treatment modalities of BA patients, in order to prolong the survival rate of their native liver. Together with transplant surgeons, the bridging of BA patients to liver transplantation (LTx) becomes optimized and as a consequence of this interdisciplinary approach, the overall survival of babies with BA has already reached 90%. Furthermore, basic research into the still unknown origin of BA has advanced, and numerous scientific programs have already linked together. The overriding interest is to discover at least BA's etiology and to turn the treatment of BA patients from a symptomatic to a causative approach. Interdisciplinary and international programs are mandatory and already existing initiatives in Europe, the United States and Japan are going to coordinate their registries, clinical trials and basic research studies for the benefit of the patients and solve the riddle of BA.

Biliary atresia with choledochal cyst: implications for classification

BACKGROUND & AIMS

To illustrate the limitations of the embryonic and perinatal classification system of biliary atresia (BA), we present a child with an antenatal diagnosis of choledochal cyst (CC) associated with BA and review the published literature.

METHODS

Medline and Pubmed were searched for "BA and CC," "cystic biliary atresia," "BA and cysts," and "biliary cystic malformations."

RESULTS

A 7-week-old with an antenatal diagnosis of CC was found to have BA associated with CC. The literature search identified 88 cases of BA with CC. Sixty-seven cases had type 1 BA (atresia of the common bile duct), 2 had type 2 BA (atresia of the common hepatic duct), and 19 had type 3 BA (atresia of the porta hepatis). Of the 27 cases of antenatal diagnosis of BA with CC only 1 had associated congenital anomalies. Outcome analysis showed poor outcomes were significantly more common (P = .009) and occurred earlier (P = .0249) in patients with type 3 BA. Children with type 3 BA were 5.4 times more likely to develop poor outcomes compared with type 1 (hazard ratio, 5.4; 95% confidence interval, 1.03-27.8).

CONCLUSIONS

BA associated with CC forms a distinct subtype of BA, characterized by a preponderance of type 1 BA, a relatively good clinical outcome after surgery, and an absence of associated congenital anomalies. Antenatal diagnosis of many affected infants supports their inclusion within the embryonic BA group and suggests that a broader interpretation of the embryonic phenotype and further classification of BA based on genetic susceptibility may be required.