Unraveling the pathogenesis and etiology of biliary atresia

Galectin-3 in biliary atresia and other pediatric cholestatic liver diseases

AIMS

Biliary atresia (BA) is characterized by intrahepatic inflammation and rapid progression of liver fibrosis. Galectin-3, a beta-galactoside binding protein, is a key regulator of inflammation and fibrosis. The aim of this study was to characterize circulating and hepatic Galectin-3 levels in children with BA.

METHODS

Plasma and liver samples were obtained from children with early BA at time of Kasai hepatoportoenterostomy, late BA at time of transplant, early and late other cholestatic liver diseases (CLD), and controls. Plasma Galectin-3 was measured using standard enzyme-linked immunoassay. Liver tissue was analyzed with multiplex immunohistochemistry and quantified using whole slide analysis. Statistical comparisons were made using nonparametric testing.

RESULTS

Plasma Galectin-3 in late BA was significantly higher than in early BA (20.82 [12.45-30.46] vs. 11.30 [8.74-16.83] ng/mL, p = 0.0096). Galectin-3 levels correlated with markers of disease severity and interleukin-6. There were significantly more Galectin-3+ M2 macrophages in late BA in comparison to late other CLD (162 [157-233] vs. 49 [33-59] cells/mm2, p = 0.03). The number of Galectin-3+ M2 macrophages correlated with the number of activated hepatic stellate cells and bile duct proliferation.

CONCLUSIONS

Plasma Galectin-3 is higher in late BA at time of transplant in comparison to early BA at time of Kasai. The number of Galectin-3 expressing M2 macrophages in late BA is elevated relative to late other CLD and was associated with other prognostic histological findings. Galectin-3 targeted therapy may be beneficial in slowing disease progression to cirrhosis in children with BA.

Ductular Reactions in Liver Injury, Regeneration, and Disease Progression-An Overview

Ductular reaction (DR) is a complex cellular response that occurs in the liver during chronic injuries. DR mainly consists of hyper-proliferative or reactive cholangiocytes and, to a lesser extent, de-differentiated hepatocytes and liver progenitors presenting a close spatial interaction with periportal mesenchyme and immune cells. The underlying pathology of DRs leads to extensive tissue remodeling in chronic liver diseases. DR initiates as a tissue-regeneration mechanism in the liver; however, its close association with progressive fibrosis and inflammation in many chronic liver diseases makes it a more complicated pathological response than a simple regenerative process. An in-depth understanding of the cellular physiology of DRs and their contribution to tissue repair, inflammation, and progressive fibrosis can help scientists develop cell-type specific targeted therapies to manage liver fibrosis and chronic liver diseases effectively.

Molecular Pathways and Animal Models of Defects in Situs

Left-right patterning is among the least well understood of the three axes defining the body plan, and yet it is no less important, with left-right patterning defects causing structural birth defects with high morbidity and mortality, such as complex congenital heart disease, biliary atresia, or intestinal malrotation. The cell signaling pathways governing left-right asymmetry are highly conserved and involve multiple components of the TGF-β superfamily of cell signaling molecules. Central to left-right patterning is the differential activation of Nodal on the left, and BMP signaling on the right. In addition, a plethora of other cell signaling pathways including Shh, FGF, and Notch also contribute to the regulation of left-right patterning. In vertebrate embryos such as the mouse, frog, or zebrafish, the specification of left-right identity requires the left-right organizer (LRO) containing cells with motile and primary cilia that mediate the left-sided propagation of Nodal signaling, followed by left-sided activation of Lefty and then Pitx2, a transcription factor that specifies visceral organ asymmetry. While this overall scheme is well conserved, there are striking species differences, including the finding that motile cilia do not play a role in left-right patterning in some vertebrates. Surprisingly, the direction of heart looping, one of the first signs of organ left-right asymmetry, was recently shown to be specified by intrinsic cell chirality, not Nodal signaling, possibly a reflection of the early origin of Nodal signaling in radially symmetric organisms. How this intrinsic chirality interacts with downstream molecular pathways regulating visceral organ asymmetry will need to be further investigated to elucidate how disturbance in left-right patterning may contribute to complex CHD.

Long-term clinical and socioeconomic outcomes of children with biliary atresia

Background

Biliary atresia (BA) is rare liver disease of unknown etiology, and is a major indication for liver transplant (LT). Previous data indicate improved outcomes with early referral for Kasai portoenterostomy (KPE).

Objective

Evaluate the long-term outcomes in BA, with particular focus on those transitioned to adult care with native livers.

Subjects and Methods

Patients with BA treated between1980 and 2012 were identified. Data were collected from the time of referral, transition to adult care, and the most recent clinic notes, from which patient and native liver survival were calculated.

Results

Four hundred and fifty-four patients with BA were identified, who were followed up for median of 16.4 years from birth; 74 died (41 of whom had a LT), giving a 20-year survival rate of 83.6%. Two hundred and seventy-two patients received an LT, with the median native liver survival being 35 months. Of patients who transitioned to adult care, 54 of 180 (30.0%) retained their native liver. Of these, 72% (39 of 54) had evidence of chronic liver disease at transition, of whom 8 were subsequently lost to follow-up, 9 were transplanted, and 22 remained stable with compensated liver disease. Of the 15 of 54 patients (28%) with no evidence of chronic disease in their native liver disease at transition, 3 were subsequently lost to follow-up; none received transplants, although 3 patients developed new-onset liver disease. All patients transitioned to adult care completed secondary school education (N = 180), with 49% having attended college/university and 87% being in employment or education at the last follow-up. Of female patients, 34% had at least one pregnancy (27 children in 21 women), while 22% of males had fathered a child.

Conclusion

Long-term outcomes in BA are good, with patients surviving into adult life. Progression of chronic liver disease and associated morbidity is common in those who retained their native livers, suggesting that these patients require monitoring of liver disease throughout adult life, and early recognition of the need for LT.

Genetic Contributions to Biliary Atresia: A Developmental Cholangiopathy

Biliary atresia (BA) is the most prevalent serious liver disease of infancy and childhood, and the principal indication for liver transplantation in pediatrics. BA is best considered as an idiopathic panbiliary cholangiopathy characterized by obstruction of bile flow and consequent cholestasis presenting during fetal and perinatal periods. While several etiologies have been proposed, each has significant drawbacks that have limited understanding of disease progression and the development of effective treatments. Recently, modern genetic analyses have uncovered gene variants contributing to BA, thereby shifting the paradigm for explaining the BA phenotype from an acquired etiology (e.g., virus, toxin) to one that results from genetically altered cholangiocyte development and function. Herein we review recently reported genetic contributions to BA, highlighting the enhanced representation of variants in biological pathways involving ciliary function, cytoskeletal structure, and inflammation. Finally, we blend these findings as a new framework for understanding the resultant BA phenotype as a developmental cholangiopathy.

Genetic alterations and molecular mechanisms underlying hereditary intrahepatic cholestasis

Hereditary cholestatic liver disease caused by a class of autosomal gene mutations results in jaundice, which involves the abnormality of the synthesis, secretion, and other disorders of bile acids metabolism. Due to the existence of a variety of gene mutations, the clinical manifestations of children are also diverse. There is no unified standard for diagnosis and single detection method, which seriously hinders the development of clinical treatment. Therefore, the mutated genes of hereditary intrahepatic cholestasis were systematically described in this review.

Plasma amyloid-beta levels correlated with impaired hepatic functions: An adjuvant biomarker for the diagnosis of biliary atresia

BACKGROUND

Biliary atresia (BA) is an infantile fibro-obstructive cholestatic disease with poor prognosis. An early diagnosis and timely Kasai portoenterostomy (KPE) improve clinical outcomes. Aggregation of amyloid-beta (Aβ) around hepatic bile ducts has been discovered as a factor for BA pathogenesis, yet whether plasma Aβ levels correlate with hepatic dysfunctions and could be a biomarker for BA remains unknown.

METHOD

Plasma samples of 11 BA and 24 controls were collected for liver function test, Aβ40 and Aβ42 measurement by enzyme-linked immunosorbent assay (ELISA). Pearson's chi-squared test or Mann-Whitney U test was performed to assess differences between groups. Correlation between Aβ42/Aβ40 and liver function parameters was performed using Pearson analysis. The area under the receiver-operative characteristic (ROC) curve (area under curve; AUC) was measured to evaluate the diagnostic power of Aβ42/Aβ40 for BA. Diagnostic enhancement was further evaluated by binary regression ROC analysis of Aβ42/Aβ40 combined with other hepatic function parameters.

RESULTS

Plasma Aβ42/Aβ40 was elevated in BA patients. Aβ42 displayed a weak positive correlation with γ-glutamyl transpeptidase (GGT) (Pearson's correlation = 0.349), while there was no correlation for Aβ40 with hepatic functions. Aβ42/Aβ40 was moderately correlated with GGT, total bile acid (TBA), direct bilirubin (DBIL) (Pearson's correlation = 0.533, 0.475, 0.480), and weakly correlated with total bilirubin (TBIL) (Pearson's correlation = 0.337). Aβ42/Aβ40 showed an acceptable predictive power for cholestasis [AUC = 0.746 (95% CI: 0.552-0.941), p < 0.05]. Diagnostic powers of Aβ42/Aβ40 together with hepatic function parameters for cholestasis were markedly improved compared to any indicator alone. Neither Aβ42/Aβ40 nor hepatic function parameters displayed sufficient power in discriminating BA from choledochal cysts (CC); however, combinations of Aβ42/Aβ40 + GGT along with any other hepatic function parameters could differentiate BA from CC-cholestasis (AUC = 1.000, p < 0.05) with a cut-off value as 0.02371, -0.28387, -0.34583, 0.06224, 0.01040, 0.06808, and 0.05898, respectively.

CONCLUSION

Aβ42/Aβ40 is a good indicator for cholestasis, but alone is insufficient for a distinction of BA from non-BA. However, Aβ42/Aβ40 combined with GGT and one other hepatic function parameter displayed a high predictive power as a screening test for jaundiced neonates who are more likely to be BA, enabling them to early intraoperative cholangiography for BA confirmation and KPE to improve surgical outcomes. However, a multi-centers validation is needed before introduction into daily clinical practice.

The Role of B Cells in Adult and Paediatric Liver Injury

B lymphocytes are multitasking cells that direct the immune response by producing pro- or anti-inflammatory cytokines, by presenting processed antigen for T cell activation and co-stimulation, and by turning into antibody-secreting cells. These functions are important to control infection in the liver but can also exacerbate tissue damage and fibrosis as part of persistent inflammation that can lead to end stage disease requiring a transplant. In transplantation, immunosuppression increases the incidence of lymphoma and often this is of B cell origin. In this review we bring together information on liver B cell biology from different liver diseases, including alcohol-related and metabolic fatty liver disease, autoimmune hepatitis, primary biliary and primary sclerosing cholangitis, viral hepatitis and, in infants, biliary atresia. We also discuss the impact of B cell depletion therapy in the liver setting. Taken together, our analysis shows that B cells are important in the pathogenesis of liver diseases and that further research is necessary to fully characterise the human liver B cell compartment.

Management of biliary atresia: To transplant or not to transplant

Kasai procedure (KP) and liver transplantation (LT) represent the only therapeutic options for patients with biliary atresia (BA), the most common indication for LT in the pediatric population. However, KP represents by no means a radical option but rather a bridging one, as nearly all patients will finally require a liver graft. More and more experts in the field of transplant surgery propose that maybe it is time for a paradigm change in BA treatment and abandon KP as transplantation seems inevitable. Inadequacy of organs yet makes this option currently not feasible, so it seems useful to find ways to maximize the efficacy of KP. In previous decades, multiple studies tried to identify these factors which opt for better results, but in general, outcomes of KP have not improved to the level that was anticipated. This review provides the framework of conditions which favor native liver survival after KP and the ones which optimize a positive LT outcome. Strategies of transition of care at the right time are also presented, as transplantation plays a key role in the surgical treatment of BA. Future studies and further organization in the transplant field will allow for greater organ availability and better outcomes to be achieved for BA patients.

Identification of a wide spectrum of ciliary gene mutations in nonsyndromic biliary atresia patients implicates ciliary dysfunction as a novel disease mechanism

Background

Biliary atresia (BA) is the most common obstructive cholangiopathy in neonates, often progressing to end-stage cirrhosis. BA pathogenesis is believed to be multifactorial, but the genetic contribution, especially for nonsyndromic BA (common form: > 85%) remains poorly defined.

Methods

We conducted whole exome sequencing on 89 nonsyndromic BA trios to identify rare variants contributing to BA etiology. Functional evaluation using patients’ liver biopsies, human cell and zebrafish models were performed. Clinical impact on respiratory system was assessed with clinical evaluation, nasal nitric oxide (nNO), high speed video analysis and transmission electron microscopy.

Findings

We detected rare, deleterious de novo or biallelic variants in liver-expressed ciliary genes in 31.5% (28/89) of the BA patients. Burden test revealed 2.6-fold (odds ratio (OR) [95% confidence intervals (CI)]= 2.58 [1.15–6.07], adjusted p = 0.034) over-representation of rare, deleterious mutations in liver-expressed ciliary gene set in patients compared to controls. Functional analyses further demonstrated absence of cilia in the BA livers with KIF3B and TTC17 mutations, and knockdown of PCNT, KIF3B and TTC17 in human control fibroblasts and cholangiocytes resulted in reduced number of cilia. Additionally, CRISPR/Cas9-engineered zebrafish knockouts of KIF3B, PCNT and TTC17 displayed reduced biliary flow. Abnormally low level of nNO was detected in 80% (8/10) of BA patients carrying deleterious ciliary mutations, implicating the intrinsic ciliary defects.

Interpretation

Our findings support strong genetic susceptibility for nonsyndromic BA. Ciliary gene mutations leading to cholangiocyte cilia malformation and dysfunction could be a key biological mechanism in BA pathogenesis.

Funding

The study is supported by General Research Fund, HMRF Commissioned Paediatric Research at HKCH and Li Ka Shing Faculty of Medicine Enhanced New Staff Start-up Fund.

Biomarkers for the diagnosis and post-Kasai portoenterostomy prognosis of biliary atresia: a systematic review and meta-analysis

To evaluate the accuracy of biomarkers for the early diagnosis of biliary atresia (BA) and prognostic stratification after Kasai portoenterostomy (KPE). We conducted a systematic review of PubMed, Web of Science, Embase, Scopus and OVID for English literature reporting BA biomarkers published before August 2020. Screening, data extraction, and quality assessment were performed in duplicate. A total of 51 eligible studies were included in the systematic review, and data from 12 (4182 subjects) were extracted for meta-analysis regarding the following 2 domains: (1) serum matrix metallopeptidase-7 (MMP-7), interleukin33 (IL-33) and γ-glutamyl transferase (GGT) to differentiate BA from non-BA; (2) the aspartate aminotransferase to platelet ratio index (APRi) to predict post-KPE liver fibrosis/cirrhosis. The summary sensitivity, specificity and area under the curve (AUC) of MMP-7 for diagnosing BA were 96%, 91% and 0.9847, respectively, and those of GGT were 80%, 79% and 0.9645, respectively. The summary sensitivity and specificity of IL-33 for diagnosing BA were 77% and 85%, respectively. The summary sensitivity and specificity of APRi for predicting post-KPE liver fibrosis were 61% and 80%, respectively, and the summary sensitivity, specificity and AUC of APRi for predicting post-KPE cirrhosis were 78%, 83% and 0.8729, respectively. Moreover, good evidence was shown in investigations of serum IL-18 and IL-33 in distinguishing BA from healthy controls, serum IL-18 for prognosis of post-KPE persistent jaundice, and serum hyaluronic acid and MMP-7 for prognosis of post-KPE significant liver fibrosis. MMP-7, IL-33 and GGT are useful biomarkers to assist in the diagnosis of BA. APRi might be used to predict post-KPE significant liver fibrosis and cirrhosis. These noninvasive biomarkers can be integrated into the management protocol of BA.

NCK-associated protein 1 like (nckap1l) minor splice variant regulates intrahepatic biliary network morphogenesis

Impaired formation of the intrahepatic biliary network leads to cholestatic liver diseases, which are frequently associated with autoimmune disorders. Using a chemical mutagenesis strategy in zebrafish combined with computational network analysis, we screened for novel genes involved in intrahepatic biliary network formation. We positionally cloned a mutation in the nckap1l gene, which encodes a cytoplasmic adaptor protein for the WAVE regulatory complex. The mutation is located in the last exon after the stop codon of the primary splice isoform, only disrupting a previously unannotated minor splice isoform, which indicates that the minor splice isoform is responsible for the intrahepatic biliary network phenotype. CRISPR/Cas9-mediated nckap1l deletion, which disrupts both the primary and minor isoforms, showed the same defects. In the liver of nckap1l mutant larvae, WAVE regulatory complex component proteins are degraded specifically in biliary epithelial cells, which line the intrahepatic biliary network, thus disrupting the actin organization of these cells. We further show that nckap1l genetically interacts with the Cdk5 pathway in biliary epithelial cells. These data together indicate that although nckap1l was previously considered to be a hematopoietic cell lineage-specific protein, its minor splice isoform acts in biliary epithelial cells to regulate intrahepatic biliary network formation.

Glial Cell Line-Derived Neurotrophic Factor, S-100 Protein and Synaptophysin Expression in Biliary Atresia Gallbladder Tissue

PURPOSE

Biliary atresia (BA) is a disease that manifests as jaundice after birth and leads to progressive destruction of the ductal system in the liver. The aim of this study was to investigate histopathological changes and immunohistochemically examine the expression of glial cell line-derived neurotrophic factor (GDNF), synaptophysin, and S-100 protein in the gallbladder of BA patients.

METHODS

The study included a BA group of 29 patients and a control group of 41 children with cholecystectomy. Gallbladder tissue removed during surgery was obtained and examined immunohistochemically and histopathologically. Tissue samples of both groups were immunohistochemically assessed in terms of GDNF, S-100 protein, and synaptophysin expression. Expression was classified as present or absent. Inflammatory activity assessment with hematoxylin and eosin staining and fibrosis assessment with Masson's trichrome staining were performed for tissue sample sections of both groups.

RESULTS

Ganglion cells were not present in gallbladder tissue samples of the BA group. Immunohistochemically, GDNF, synaptophysin, and S-100 expression was not detected in the BA group. Histopathological examination revealed more frequent fibrosis and slightly higher inflammatory activity in the BA than in the control group.

CONCLUSION

We speculate that GDNF expression will no longer continue in this region, when the damage caused by inflammation of the extrahepatic bile ducts reaches a critical threshold. The study's findings may represent a missing link in the chain of events forming the etiology of BA and may be helpful in its diagnosis.

Whole exome sequencing analysis for mutations in isolated type III biliary atresia patients

Aim of the study

Biliary atresia is an idiopathic, destructive disease that affects both extrahepatic and intrahepatic bile ducts with severe inflammation and manifests as progressive jaundice within the first few months of life. In this study, we aimed to investigate the significance of genetic mutations in the onset of biliary atresia disease.

Material and methods

With the approval of the ethics committee and parental consent, blood was taken from patients to obtain their DNA, and the study commenced. In this prospective study, we examined the DNA of 10 patients with no disease other than biliary atresia, and an exome sequence analysis was performed with the new-generation DNA sequencing method. The genetic structure of biliary atresia disease was examined by statistical analysis of the mutations, which were determined according to the reference DNA sequencing.

Results

In the exome sequence analysis, the number of mutations detected among the patients changed significantly; the lowest number was 12,591, and the maximum was 19,863. By examining these mutations, we identified the mutated genes that were common to all patients.

Conclusions

In this study, the highest mutation rates were detected in the PRIM2 and MAP2K3 genes. These genes have not previously been associated with biliary atresia.

Reduced Immunohistochemical Expression of Hnf1β and FoxA2 in Liver Tissue Can Discriminate Between Biliary Atresia and Other Causes of Neonatal Cholestasis

Biliary atresia (BA) is a necroinflammatory occlusive cholangiopathy that affects infants. Genetic and environmental factors has been proposed for its occurrence. The objectives of this study was to investigate the protein expression of 2 important genes regulating ductal plate remodeling, hepatocyte nuclear factor 1-beta (Hnf1β) and the fork head box protein A2 (FoxA2) in liver tissue from patients with BA and to compare their expression with other causes of neonatal cholestasis (NC). This retrospective study included 60 pediatric patients, 30 with BA and 30 with NC. Immunohistochemistry of Hnf1β and FoxA2 was performed on liver tissues from studied patients as well as 20 healthy subjects. Statistical analysis between immunohistochemistry results and other parameters was performed. Liver tissue from patients with BA revealed reduced Hnf1β and FoxA2 immunoexpression. A strong significant statistical difference between BA and NC group (P<0.0001) with regard to Hnf1β and FoxA2 immunoexpression was evident. Moreover, Hnf1β was significantly correlated with FoxA2 immunoexpression, stage of fibrosis, bile ductular proliferation, and bile plugs in bile ductules. Hnf1β immunoreaction in BA cases showed 76.7% sensitivity, 90% specificity, 88.5% positive predictive value, 79.4% negative predictive value, and 83.4% accuracy. FoxA2 expression in BA cases revealed 70.0% sensitivity, 80.0% specificity, 77.8% positive predictive value, 72.7% negative predictive value, 75.0% accuracy. Hnf1β and FoxA2 immunoexpression could differentiate between BA from other cause of NC.

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.

Preoperative alkaline phosphatase is a potential predictor of short-term outcome of surgery in infants with biliary atresia

Aim of the study

Biliary atresia (BA) is a fibro-inflammatory cholangiopathy of intra- and extrahepatic biliary radicles. The standard-of-care treatment is surgical restoration of bile flow by Kasai hepatoportoenterostomy (HPE). We aimed to identify the predictors of short-term outcome of the Kasai operation three months postoperatively.

Material and methods

This retrospective study included 107 infants diagnosed with BA by intraoperative cholangiography. All underwent a Kasai operation. The surgical outcome was classified after 3 months post-operatively as successful (bilirubin ≤ 2 mg/dl) or failed (bilirubin > 2 mg/dl). The two groups were compared according to basic clinical, ultrasonographic and histopathological characteristics.

Results

Of the studied patients 29 (27.1%) had a successful outcome while 78 (72.9%) had failed Kasai HPE. Of the preoperative characteristics, lower age and lower serum alkaline phosphatase (ALP) were significantly associated with successful surgical outcome (p = 0.009 and < 0.0001, respectively). In addition, surgical type of BA affected the short-term outcome (p = 0.017), while there was no statistically significant difference regarding the other studied parameters between groups. Age of 69.5 days or less was predictive of successful outcome with 74.4% specificity but with low sensitivity (58.6%), and ALP at a cutoff level of 532.5 U/l or less was predictive of successful outcome with 75.9% sensitivity and 74.4% specificity.

Conclusions

Younger age at the time of surgery and lower ALP are good predictors for the short-term outcome of Kasai HPE with better performance of ALP. This may help to anticipate those who can benefit from surgical correction and those who should be given high priority for transplant referral.

RNA-seq reveals outcome-specific gene expression of MMP7 and PCK1 in biliary atresia

The disease phenotype in biliary atresia (BA) is caused by a fibro-inflammatory process leading to destruction of cholangiocytes, obstruction of ductular pathways and eventual progression to liver cirrhosis. The first line of management is a Kasai portoenterostomy (KPE) followed by liver transplantation (LT) in some children. Several factors have been postulated to affect the outcome of KPE and/or the subsequent progression of liver disease. However, no biomarkers have been identified in the liver for BA. We aimed to address this deficit. Whole transcriptome mRNA sequencing was performed for 29 samples (25 BA and 4 Controls) to identify the candidate genes predicting the prognosis of KPE. These results were further confirmed with quantitative Realtime PCR (qPCR). Analysis from RNA-sequencing data identified matrix metalloproteinase7 (MMP7) and phosphoenolpyruvate carboxykinase (PCK1) as potential determinants of the outcome of KPE. MMP7 expression was significantly elevated in patients who failed to clear jaundice after KPE as well as in patients with End Stage Liver Disease (ESLD). In contrast, PCK1 level was upregulated in patients who had successful KPE, while there was a significant down regulation in patients who failed KPE. MMP7 and PCK1 expression patterns had an inverse relation to the outcome of KPE and hence could potentially be used as biomarkers to predict KPE outcome and disease progression, enabling clinicians to design new treatment strategies for BA.

Preoperative alkaline phosphatase is a potential predictor of short-term outcome of surgery in infants with biliary atresia

AIM OF THE STUDY

Biliary atresia (BA) is a fibro-inflammatory cholangiopathy of intra- and extrahepatic biliary radicles. The standard-of-care treatment is surgical restoration of bile flow by Kasai hepatoportoenterostomy (HPE). We aimed to identify the predictors of short-term outcome of the Kasai operation three months postoperatively.

MATERIAL AND METHODS

This retrospective study included 107 infants diagnosed with BA by intraoperative cholangiography. All underwent a Kasai operation. The surgical outcome was classified after 3 months post-operatively as successful (bilirubin ≤ 2 mg/dl) or failed (bilirubin > 2 mg/dl). The two groups were compared according to basic clinical, ultrasonographic and histopathological characteristics.

RESULTS

Of the studied patients 29 (27.1%) had a successful outcome while 78 (72.9%) had failed Kasai HPE. Of the preoperative characteristics, lower age and lower serum alkaline phosphatase (ALP) were significantly associated with successful surgical outcome (p = 0.009 and < 0.0001, respectively). In addition, surgical type of BA affected the short-term outcome (p = 0.017), while there was no statistically significant difference regarding the other studied parameters between groups. Age of 69.5 days or less was predictive of successful outcome with 74.4% specificity but with low sensitivity (58.6%), and ALP at a cutoff level of 532.5 U/l or less was predictive of successful outcome with 75.9% sensitivity and 74.4% specificity.

CONCLUSIONS

Younger age at the time of surgery and lower ALP are good predictors for the short-term outcome of Kasai HPE with better performance of ALP. This may help to anticipate those who can benefit from surgical correction and those who should be given high priority for transplant referral.

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.

No association between month of birth and biliary atresia in a country with tropical climate

AIM

Children with biliary atresia (BA) born in countries with temperate climate showed month-of-birth (MoB) predilection during cooler months. To date, no study on the MoB-BA association has been performed in a tropical country. Our aim was to define MoB variation in children with BA in a tropical country.

METHODS

We studied 150 children diagnosed with BA between January 1996 and April 2015 at a teaching hospital. MoB was defined by two categories based on the precipitation: rain and dry, and three categories based on the air temperature: high, average and low. We applied the country's population data on the number of births in each period as the expected proportions of birth.

RESULTS

A slightly higher proportion of BA children was born in the rainy months (52.7%); however, the difference was not significant compared to the general population's birth (P = 0.87). For the MoB based on the air temperature, no statistically significant difference was noted. Males with BA seemed to have a greater MoB variation compared to females, but this did not reach statistical significance.

CONCLUSION

We could not find an association between MoB and BA in a tropical country. Multinational studies may aid in understanding the MoB-BA association in the tropical countries.

The Prognostic Value of CD8+ and CD45RO+ T Cells Infiltration and Beclin1 Expression Levels for Early Postoperative Cholangitis of Biliary Atresia Patients after Kasai Operation

BACKGROUND

Postoperative cholangitis is a common but severe complication after Kasai portoenterostomy for biliary atresia (BA). This study aimed to identify its prognostic factors.

METHODS

Two sets of liver paraffin-embedded tissue samples were collected from BA patients who received Kasai portoenterostomy (n = 25 and n = 31, respectively). Patients were divided into non-cholangitis and cholangitis groups. The infiltration of CD4⁺, CD8⁺, CD45RO⁺, CD68⁺ cells and expression of Beclin1 were quantitatively evaluated in immunohistochemical analysis.

RESULTS

Cholangitis group had a significantly lower CD8⁺ T cell infiltration but a higher CD45RO⁺ cell infiltration, and a lower Beclin1 level than non-cholangitis group (all P < 0.01). Multivariate logistic regression analysis indicated that infiltration of CD8⁺ cells (odds ratio [OR], 0.112; 95% confidence interval [CI], 0.022-0.577) and CD45RO⁺ cells (OR, 3.88; 95% CI, 1.37-11.03), and Beclin1 level (OR, 0.088; 95% CI, 0.018-0.452) were independent influence factors for early postoperative cholangitis. Receiver operating characteristic (ROC) analysis showed that area under ROC curve (AUROC) values for CD8⁺ cells, CD45RO⁺ cells and Beclin1 were 0.857, 0.738 and 0.900, respectively.

CONCLUSION

Our findings demonstrated the CD8⁺ cells, CD45RO⁺ cells and Beclin1 level possessed the prognostic value for early postoperative cholangitis following Kasai operation, which may be helpful to develop new prevention and treatment strategies for postoperative cholangitis.

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.

MicroRNA-155 modulates bile duct inflammation by targeting the suppressor of cytokine signaling 1 in biliary atresia

BackgroundBiliary atresia (BA) is an etiologically perplexing disease, manifested by neonatal cholestasis, repeated cholangitis, and progressive biliary fibrosis. MiR-155 has been implicated to modulate the immune response, which contributes to biliary injury. However, its potential role in the pathogenesis of BA has not been addressed so far.MethodsThe microRNA changes from BA patients and controls were identified via microarray. The immunomodulatory function of miR-155 was investigated via cell transfection and reporter assay. The lentiviral vector pL-miR-155 inhibitor was transfected into a mouse model to investigate its role in BA.ResultsThe expression of miR-155 in livers of BA patients was significantly increased, and an inverse correlation between miR-155 and suppressor of cytokine signaling 1 (SOCS1) was detected. MiR-155 overexpression promoted expressions of major histocompatibility complex (MHC) I, MHC II, Chemokine (C-X-C motif) ligand (CXCL) 9, CXCL10, monocyte chemotactic protein 1, and CXCL1 after IFN-γ stimulation, which could be suppressed by SOCS1 overexpression. Moreover, miR-155 overexpression activated JAK2/STAT3, thus enhancing the pro-inflammatory effect. Downregulating miR-155 reduced the incidence of BA in a rhesus monkey rotavirus-induced BA model.ConclusionOur results reveal a vital contribution of miR-155 upregulation and consequent SOCS1 downregulation to an immune response triggered via IFN-γ in BA.

Three-dimensional structural analysis reveals a Cdk5-mediated kinase cascade regulating hepatic biliary network branching in zebrafish

The intrahepatic biliary network is a highly branched three-dimensional network lined by biliary epithelial cells, but how its branching patterns are precisely established is not clear. We designed a new computer-based algorithm that quantitatively computes the structural differences of the three-dimensional networks. Utilizing the algorithm, we showed that inhibition of Cyclin-dependent kinase 5 (Cdk5) led to reduced branching in the intrahepatic biliary network in zebrafish. Further, we identified a previously unappreciated downstream kinase cascade regulated by Cdk5. Pharmacological manipulations of this downstream kinase cascade produced a crowded branching defect in the intrahepatic biliary network and influenced actin dynamics in biliary epithelial cells. We generated larvae carrying a mutation in cdk5 regulatory subunit 1a (cdk5r1a), an essential activator of Cdk5. cdk5r1a mutant larvae show similar branching defects as those observed in Cdk5 inhibitor-treated larvae. A small-molecule compound that interferes with the downstream kinase cascade rescued the mutant phenotype. These results provide new insights into branching morphogenesis of the intrahepatic biliary network.

Prenatal diagnosis of biliary atresia: A case series

BACKGROUND

Biliary atresia is a progressive disease presenting with jaundice, and is the most common indication for liver transplantation in the pediatric population. Prenatal series have yielded conflicting results concerning a possible association between BA and prenatal nonvisualization of the gallbladder.

AIMS

This retrospective case series was performed to assess the association between biliary atresia, prenatal nonvisualization of the gallbladder and other sonographic signs.

STUDY DESIGN/SUBJECTS

We identified biliary atresia patients who underwent a Kasai procedure by a single pediatric surgeon and/or follow up by a single pediatric gastroenterologist. Axial plane images and/or video recordings were scrutinized for sonographic signs of biliary atresia on the second trimester anomaly scan.

OUTCOME MEASURES

Proportion of biliary atresia cases with prenatal sonographic signs.

RESULTS

Twenty five charts of children with biliary and high quality prenatal images were retrieved. 6/25 (24%) of cases analyzed had prenatal nonvisualization of the gallbladder or a small gallbladder on the prenatal scan. Two cases had biliary atresia splenic malformation syndrome. None of the cases had additional sonographic markers of biliary atresia.

CONCLUSIONS

Our study suggests that in addition to the well-established embryonic and cystic forms, an additional type can be suspected prenatally, which is characterized by prenatal nonvisualization of the gallbladder in the second trimester. This provides additional evidence that some cases of BA are of fetal rather than perinatal onset and may have important implications for prenatal diagnosis, for counseling and for research of the disease's etiology and pathophysiology.

Embryonic cholecystitis and defective gallbladder contraction in the Sox17-haploinsufficient mouse model of biliary atresia

The gallbladder excretes cytotoxic bile acids into the duodenum through the cystic duct and common bile duct system. Sox17 haploinsufficiency causes biliary atresia-like phenotypes and hepatitis in late organogenesis mouse embryos, but the molecular and cellular mechanisms underlying this remain unclear. In this study, transcriptomic analyses revealed the early onset of cholecystitis in Sox17^+/- embryos, together with the appearance of ectopic cystic duct-like epithelia in their gallbladders. The embryonic hepatitis showed positive correlations with the severity of cholecystitis in individual Sox17^+/- embryos. Embryonic hepatitis could be induced by conditional deletion of Sox17 in the primordial gallbladder epithelia but not in fetal liver hepatoblasts. The Sox17^+/- gallbladder also showed a drastic reduction in sonic hedgehog expression, leading to aberrant smooth muscle formation and defective contraction of the fetal gallbladder. The defective gallbladder contraction positively correlated with the severity of embryonic hepatitis in Sox17^+/- embryos, suggesting a potential contribution of embryonic cholecystitis and fetal gallbladder contraction in the early pathogenesis of congenital biliary atresia.

Preoperative Serum IL-12p40 Is a Potential Predictor of Kasai Portoenterostomy Outcome in Infants with Biliary Atresia

The standard-of-care treatment for biliary atresia (BA) is surgical restoration of bile flow by Kasai portoenterostomy. We aimed to study serum interleukin- (IL-) 12p40, a natural antagonist for the proinflammatory IL-12p70, and its relation to surgical outcomes of BA. The study included 75 infants with neonatal cholestasis: BA group (n = 25), non-BA cholestasis group (n = 30), and neglected BA group (n = 20), in addition to thirty healthy neonates serving as controls. IL-12p40 was measured by ELISA in all individuals and a second assessment was performed 3 months postoperatively in the BA group. The surgical outcomes were classified as successful (bilirubin ≤ 2 mg/dl) or failed (bilirubin > 2 mg/dl). IL-12p40 was higher in BA compared to that in the non-BA and control groups (P values were 0.036 and <0.0001, resp.) but comparable to that in the neglected BA group. Preoperative IL-12p40 levels in BA patients were significantly higher in successful Kasai compared with failed Kasai and a cutoff level of 547.47 pg/ml could predict the successful outcome with 87.5% sensitivity and 82.4% specificity. Three-month postoperative IL-12p40 tended to decrease in both the successful and failed groups. In conclusion, preoperative serum IL-12p40 is a potential predictor of Kasai outcome. Serial postoperative measurements may anticipate the failure of an initially successful operation, hence the need for liver transplantation.

Biliary atresia: Where do we stand now?

The pathway from clinical suspicion to establishing the diagnosis of biliary atresia in a child with jaundice is a daunting task. However, investigations available help to point towards the correct diagnosis in reasonable time frame. Imaging by Sonography has identified several parameters which can be of utility in the diagnostic work up. Comparison of Sonography with imaging by Nuclear medicine can bring out the significant differences and also help in appropriate imaging. The battery of Biochemical tests, available currently, enable better understanding of the line-up of investigations in a given child with neonatal cholestasis. Management protocols enable standardized care with optimal outcome. The place of surgical management in biliary atresia is undisputed, although Kasai procedure and primary liver transplantation have been pitted against each other. This article functions as a platform to bring forth the various dimensions of biliary atresia.

Biliary atresia in Vietnam: Management and the burden of disease

BACKGROUND

Biliary atresia is an idiopathic, neonatal liver disease of the bile ducts. The natural evolution of biliary atresia is known in developed countries. This study describes the clinical course of biliary atresia in Vietnam, a developing country.

METHODS

Chart reviews were undertaken of patients treated with or without the Kasai procedure between January 2010 and July 2013 at a children's hospital in Vietnam.

RESULTS

Of 287 children with biliary atresia, 149 (52%) were treated without the Kasai procedure and 138 (48%) were treated with the Kasai procedure. Median age at diagnosis was 2.4 months for children treated without the Kasai procedure vs 2.3 months for those treated with the procedure. The percentages of patients in the group treated without the Kasai procedure presenting at <2 months, 2 to <3 months, 3 to <4 months, 4-6 months, and >6 months of age were 31%, 35%, 15%, 10%, and 9%, respectively, compared to those treated with the Kasai procedure at 36% (P = .38), 44% (P = .12), 16% (P = 1.0), 4% (P = .037), and 0% (P < .001), respectively. The group treated without the Kasai procedure had 1- and 2-year survivals of 52% and 28%, respectively (median survival 6.6 months); in contrast, the group treated with the Kasai procedure had 1- and 2-year transplant-free survivals of 84% and 71%. No patients were treated by liver transplantation because of lack of a liver transplantation program in Vietnam.

CONCLUSION

The majority of biliary atresia in Vietnam remains untreated despite early presentation and reasonable outcomes after a Kasai procedure relative to Western countries. These data illustrate the high health care burden for biliary atresia in Vietnam and the need to improve education about biliary atresia and its treatment.

Brain-Derived Neurotrophic Factor in Children and Adolescents with Cirrhosis Due to Biliary Atresia

BACKGROUND

The nutritional status in patients with cirrhosis is not so easy to assess properly. Considering the relationship between brain-derived neurotrophic factor (BDNF) and energy homeostasis, the main aim of this study was to evaluate the concentration of BDNF in children and adolescents with cirrhosis due to biliary atresia (BA) and correlate it with their nutritional status.

METHODS

Fifty-three children and adolescents with cirrhosis due to BA and 33 healthy controls were enrolled in this study. Nutritional status was evaluated using anthropometric parameters, and serum BDNF was measured by ELISA. Spearman coefficient was used to evaluate the correlation between variables.

RESULTS

In the cirrhosis group, 28.8% were undernourished and in the control group, 100% were well-nourished. BDNF median values for the control and cirrhosis group were 28.5 and 9.0 pg/ml respectively. BDNF and platelets were positively associated with both Standard Deviation Score (SDS) for height-for-age ratio and SDS for triceps skinfold thickness-for-age ratio.

CONCLUSIONS

Considering these associations, BDNF may be an indirect biomarker of nutritional status in children and adolescents with chronic liver disease. Further studies must be conducted to clarify the role of BDNF in this population.

26-Year-Old Survivor of Kasai Procedure With Native Liver

A 26-year old woman with history of congenital biliary atresia and Kasai procedure as a newborn presented with recurrent nausea and abdominal pain. Physical examination showed anicteric sclera and tender right upper quadrant. Elevated liver function tests suggested obstruction and hepatitis. Percutaneous transhepatic cholangiogram showed generalized ductal dilation, innumerable intrahepatic bile duct stones, and multiple filling defects. No anastomotic stenosis was noted. The patient was treated for acute symptoms and referred to a liver transplant center. Long-term survivors of the Kasai procedure with a native liver are rare, and this represents the third known U.S. case in the literature.

Rotavirus Infects Human Biliary Epithelial Cells and Stimulates Secretion of Cytokines IL-6 and IL-8 via MAPK Pathway

Biliary atresia (BA) is an infantile inflammatory cholangiopathy of unknown etiology although epidemiologic studies and animal models utilizing rotavirus (RV) have suggested a role for viral infection. Proinflammatory and profibrotic cytokines have been detected in infants with BA. The purpose of our study was to investigate the susceptibility of human cholangiocytes (H69 cells) to infection with RRV and to determine if this infection resulted in cytokine secretion. Infection of H69 cells by RRV was noncytolytic and resulted in a time-dependent increase in the release of both infectious virions and cytokines IL-6 and IL-8 into the supernate. The greatest difference in cytokine supernatant levels between infected and mock-infected cells was noted at 24 hours postinfection (h p.i.) for IL-8, 556 ± 111 versus 77 ± 68 pg/mL (p < 0.0001), and at 48 h p.i. for IL-6, 459 ± 64 versus 67 ± 2 pg/mL (p < 0.0001). Production of both cytokines following RRV infection was significantly reduced by pretreating the H69 cells with inhibitors of mitogen-activated protein kinase (MAPK). Conclusion. RRV can infect human cholangiocytes resulting in the production of proinflammatory and profibrotic cytokines via the MAPK pathway. RRV-infected H69 cells could be a useful model system for investigating the viral hypothesis of BA.

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.

The Sea Lamprey as an Etiological Model for Biliary Atresia

Biliary atresia (BA) is a progressive, inflammatory, and fibrosclerosing cholangiopathy in infants that results in obstruction of both extrahepatic and intrahepatic bile ducts. It is the most common cause for pediatric liver transplantation. In contrast, the sea lamprey undergoes developmental BA with transient cholestasis and fibrosis during metamorphosis, but emerges as a fecund adult with steatohepatitis and fibrosis in the liver. In this paper, we present new histological evidence and compare the sea lamprey to existing animal models to highlight the advantages and possible limitations of using the sea lamprey to study the etiology and compensatory mechanisms of BA and other liver diseases. Understanding the signaling factors and genetic networks underlying lamprey BA can provide insights into BA etiology and possible targets to prevent biliary degeneration and to clear fibrosis. In addition, information from lamprey BA can be used to develop adjunct treatments for patients awaiting or receiving surgical treatments. Furthermore, the cholestatic adult lamprey has unique adaptive mechanisms that can be used to explore potential treatments for cholestasis and nonalcoholic steatohepatitis (NASH).

Genome-wide association studies in biliary atresia

Biliary atresia (BA) is a model complex disease resulting from interactions between multiple susceptibility loci and environmental factors. This perception is based on a heterogeneous phenotype extending beyond an absent extrahepatic bile duct to include gut and cardiovascular anomalies, and the association of BA with viral infections. Refractory jaundice and progression to cirrhosis shortly after birth can be fatal without surgical correction, and further suggests a pathogenesis during liver and bile duct development. Conclusive proof for a developmental origin would require documentation of disease progression in the perinatal or fetal liver, an impossible task for obvious reasons. We review three different sets of genome-wide association studies (GWAS) from three different cohorts of BA patients by three different groups of investigators, which address this knowledge gap. Knockdown of each susceptibility gene identified by GWAS in zebrafish embryos impairs excretion of bile from the liver, duplicating the characteristic diagnostic finding seen in affected children. This finding is associated with impaired intrahepatic biliary network formation in zebrafish morphants. Although distinct, these susceptibility genes share several functions including roles in mechanisms for organogenesis (glypican 1 or GPC1, and adenosine diphosphate ribosylation factor 6, or ARF6) or a greater expression in fetal liver than in adult liver (adducin 3 or ADD3). Together, these studies emphasize the importance of the human evidence, and present opportunities to map novel pathways which explain the phenotypic heterogeneity of BA.

Neonatal Cholestasis - Differential Diagnoses, Current Diagnostic Procedures, and Treatment

Cholestatic jaundice in early infancy is a complex diagnostic problem. Misdiagnosis of cholestasis as physiologic jaundice delays the identification of severe liver diseases. In the majority of infants, prolonged physiologic jaundice represent benign cases of breast milk jaundice, but few among them are masked and caused by neonatal cholestasis (NC) that requires a prompt diagnosis and treatment. Therefore, a prolonged neonatal jaundice, longer than 2 weeks after birth, must always be investigated because an early diagnosis is essential for appropriate management. To rapidly identify the cases with cholestatic jaundice, the conjugated bilirubin needs to be determined in any infant presenting with prolonged jaundice at 14 days of age with or without depigmented stool. Once NC is confirmed, a systematic approach is the key to reliably achieve the diagnosis in order to promptly initiate the specific, and in many cases, life-saving therapy. This strategy is most important to promptly identify and treat infants with biliary atresia, the most common cause of NC, as this requires a hepatoportoenterostomy as soon as possible. Here, we provide a detailed work-up approach including initial treatment recommendations and a clinically oriented overview of possible differential diagnoses in order to facilitate the early recognition and a timely diagnosis of cholestasis. This approach warrants a broad spectrum of diagnostic procedures and investigations including new methods that are described in this review.

Replication of a GWAS signal in a Caucasian population implicates ADD3 in susceptibility to biliary atresia

In the United States, biliary atresia (BA) is the most frequent indication for liver transplantation in pediatric patients. BA is a complex disease, with suspected environmental and genetic risk factors. A genome-wide association study in Chinese patients identified association to the 10q24.2 (hg18) genomic region. This signal was upstream of two genes, XPNPEP1 and ADD3, both expressed in intrahepatic bile ducts. We tested association to this region in 171 BA patients and 1,630 controls of European descent and found the strongest signal to be at rs7099604 (p = 2.5 × 10(-3)) in intron 1 of the ADD3 gene. Moreover, expression data suggest that ADD3, but not XPNPEP1, is differentially expressed in BA patients. The role of ADD3 in biliary development is unclear, but our findings suggest that this gene may be functionally relevant for the development of BA.

Aetiology of biliary atresia: what is actually known?

Biliary atresia (BA) is a rare disease of unknown etiology and unpredictable outcome, even when there has been timely diagnosis and exemplary surgery. It has been the commonest indication for liver transplantation during childhood for the past 20 years. Hence much clinical and basic research has been directed at elucidating the origin and pathology of BA. This review summarizes the current clinical variations of BA in humans, its occasional appearance in animals and its various manifestations in the laboratory as an experimental model.

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.

Clues to the etiology of bile duct injury in biliary atresia

Biliary atresia (BA) is an infantile obstructive cholangiopathy of unknown etiology with suboptimal therapy, which is responsible for 40 to 50% of all pediatric liver transplants. Although the etiology of bile duct injury in BA in unknown, it is postulated that a pre- or perinatal viral infection initiates cholangiocyte apoptosis and release of antigens that trigger a Th1 immune response that leads to further bile duct injury, inflammation, and obstructive fibrosis. Humoral immunity and activation of the innate immune system may also play key roles in this process. Moreover, recent investigations from the murine BA model and human data suggest that regulatory T cells and genetic susceptibility factors may orchestrate autoimmune mechanisms. What controls the coordination of these events, why the disease only occurs in the first few months of life, and why a minority of infants with perinatal viral infections develop BA are remaining questions to be answered.

Reappraise the effect of redo-Kasai for recurrent jaundice following Kasai operation for biliary atresia in the era of liver transplantation

PURPOSE

This study was conducted to reappraise the efficacy of redo-Kasai (or revision) in the era of liver transplantation as a treatment option in those patients with recurrent jaundice after initially successful Kasai procedure.

METHODS

We studied ten patients that received redo-Kasai, among a total of 102 patients diagnosed with biliary atresia after receiving Kasai operation from 1986 to 2011.

RESULTS

Kasai operation was done at a median age of 55 days and redo-Kasai at 150 days. The bilirubin levels returned to normal in six patients after the procedure. Four of six enjoyed jaundice-free survival with native liver till the time of last follow-up. Three patients died and three received liver transplantation (LT). Only one out of seven patients with three or more episodes of cholangitis survived with native liver, while all the three patients with 1 or 0 episode survived with native liver. The difference was significant (P = 0.033). Re-do Kasai did not result in more blood loss or operative time during LT.

CONCLUSION

Redo-Kasai is still valuable in the era of LT and the episodes of cholangitis are the decisive factors affecting the outcome of the procedure.