Recent advances in the pathogenesis and management of biliary atresia

Biliary atresia: the development, pathological features, and classification of the bile duct

Biliary atresia is an occlusive biliary disease involving intrahepatic and extrahepatic bile ducts. Its etiology and pathogenesis are unclear. There are many manifestations of bile duct involvement in biliary atresia, but little is known about its occurrence and development. In addition, different classification methods have been proposed in different periods of biliary atresia, each with its advantages and disadvantages. The combined application of biliary atresia classification will help to improve the survival rate of patients with native liver. Therefore, this article reviews the development, pathological features, and classification of intrahepatic and extrahepatic bile ducts in biliary atresia, to provide a reference for the study of the pathogenesis and the choice of treatment methods.

Development of liver inflammatory injury in biliary atresia: from basic to clinical research

Biliary atresia (BA) is a severe cholangiopathy in infants. It is characterized by inflammatory fibro-obliteration of the intra- and extrahepatic bile ducts. Although the restoration of bile flow can be successful after Kasai operation, the rapid progression of liver fibrosis can continue, leading to cirrhosis. It is believed that the progression of liver fibrosis in BA is exacerbated by complicated mechanisms other than the consequence of bile duct obstruction. The fibrogenic cascade in BA liver can be divided into three stages, including liver inflammatory injury, myofibroblast activation, and fibrous scar formation. Recent studies have revealed that the activation of an immune response following bile duct injury plays an important role in promoting the inflammatory process, the releasing of inflammatory cytokines, and the development of fibrogenesis in BA liver. In this article, we summarized the evidence regarding liver inflammatory injury and the possible mechanisms that explain the rapid progression of liver fibrosis in BA.

Prominin-1 promotes restitution of the murine extrahepatic biliary luminal epithelium following cholestatic liver injury

BACKGROUND AND AIMS

Restitution of the extrahepatic biliary luminal epithelium in cholangiopathies is poorly understood. Prominin-1 (Prom1) is a key component of epithelial ciliary body of stem/progenitor cells. Given that intrahepatic Prom1-expressing progenitor cells undergo cholangiocyte differentiation, we hypothesized that Prom1 may promote restitution of the extrahepatic bile duct (EHBD) epithelium following injury.

APPROACH AND RESULTS

Utilizing various murine biliary injury models, we identified Prom1-expressing cells in the peribiliary glands of the EHBD. These Prom1-expressing cells are progenitor cells which give rise to cholangiocytes as part of the normal maintenance of the EHBD epithelium. Following injury, these cells proliferate significantly more rapidly to re-populate the biliary luminal epithelium. Null mutation of Prom1 leads to significantly >10-fold dilated peribiliary glands following rhesus rotavirus-mediated biliary injury. Cultured organoids derived from Prom1 knockout mice are comprised of biliary progenitor cells with altered apical-basal cellular polarity, significantly fewer and shorter cilia, and decreased organoid proliferation dynamics consistent with impaired cell motility.

CONCLUSIONS

We, therefore, conclude that Prom1 is involved in biliary epithelial restitution following biliary injury in part through its role in supporting cell polarity.

TWEAK/FN14 promotes profibrogenic pathway activation in Prominin-1-expressing hepatic progenitor cells in biliary atresia

BACKGROUND AND AIMS

Biliary atresia (BA), a congenital cholestatic liver disease, commonly culminates in end-stage liver disease. We previously demonstrated in BA that Prominin-1 ( Prom1 )-expressing hepatic progenitor cells (HPCs) expand within regions of developing fibrosis, giving rise to cholangiocytes within biliary ductular reactions. Null mutation of Prom1 or ablation of cells expressing Prom1 significantly diminishes fibrogenesis. FN14, the receptor for TNF-like weak inducer of apoptosis (TWEAK), is expressed by HPCs. TWEAK/FN14 signaling promotes fibrosis in multiple organ systems. Therefore, we hypothesized that TWEAK/FN14 signaling mediates Prom1 -expressing HPC proliferation leading to profibrogenic ductular reactions in BA.

APPROACH AND RESULTS

The experimental mouse model of BA mediated by perinatal rhesus rotavirus (RRV) infection resulted in increased co-expression of Fn14 in Prom1 -expressing HPCs within regions of ductular reactions. FN14 antagonist L524-0366 decreased ductular reactions, biliary fibrosis and periportal fibroblast activation in RRV injury. L524-0366 inhibition also demonstrated loss of downstream noncanonical NF-kB signaling expression in RRV injury. Murine HPC organoids demonstrated accelerated organoid growth and proliferation when treated with recombinant TWEAK. Increased organoid proliferation with recombinant TWEAK was lost when also treated with L524-0366. Analysis of a large publicly available RNA sequencing database of BA and normal control patients revealed significant increases in expression of PROM1 , FN14 , and genes downstream of TNF signaling and noncanonical NF-κB signaling pathways in BA infants. Infants who failed to achieve bile drainage after hepatoportoenterostomy had higher relative levels of FN14 expression.

CONCLUSION

TWEAK/FN14 signaling activation in Prom1 -expressing HPCs contributes to proliferation of profibrogenic ductular reactions in BA.

Systemic cytokine profiles in biliary atresia

Background

Inflammation and immune dysregulation persuade biliary duct injury in biliary atresia (BA), a leading cause of pediatric liver transplantation given lack of specific biomarkers. We aimed to determine associations between systemic cytokine profiles and clinical parameters in BA patients and to identify potential BA biomarkers.

Methods

Systemic levels of 27 cytokines were measured in 82 BA patients and 25 healthy controls using a multiplex immunoassay. Relative mRNA expressions of candidate cytokines in 20 BA livers and 5 non-BA livers were assessed using quantitative real-time PCR.

Results

Higher levels of 17 cytokines including IL-1β, IL-6, IL-7, IL-8, IL-9, IL-2, IL-15, eotaxin, IP-10, MCP-1, MIP-1α, MIP-1β, G-CSF, IL-1ra, IL-4, IL-5, and IL-10 and lower levels of IFN-α and PDGF were significantly associated with BA. In BA patients, increased levels of IL-7, eotaxin, IP-10, and IL-13 were significantly associated with unfavorable outcomes including jaundice, fibrosis, and portal hypertension. Indeed, systemic levels of those cytokines were significantly correlated with clinical parameters indicating jaundice, fibrosis, and hepatic dysfunction in BA patients. Out of 27 cytokines, 4 (IL-8, IP-10, MCP-1, and PDGF) had potential as sensitive and specific biomarkers of BA. Of these, higher IL-8 levels were significantly associated with reduced survival of BA. In BA livers, relative mRNA expressions of IL-8, IP-10, and MCP-1 were significantly up-regulated.

Conclusions

Higher levels of several cytokines including inflammatory cytokines, immunomodulatory cytokines, chemokines, and anti-inflammatory cytokines and lower levels of growth factors would reflect inflammatory and immune responses related to BA development. Among 27 cytokines, plasma IL-8 might have great potential as a diagnostic and prognostic biomarker for BA.

Association between mitochondrial and nuclear DNA damages and cellular senescence in the patients with biliary atresia undergoing Kasai portoenterostomy and liver transplantation

Biliary atresia (BA) is a cholestatic disease with extrahepatic bile duct obstruction that requires early surgical intervention and occasionally liver transplantation (LT). Accumulation of toxic bile acids induces oxidative stress that results in cell damage, such as cell senescence, mitochondrial dysfunction and others. However, details of their reciprocal association and clinical significance are unexplored. Therefore, we used immuno-localization of markers for cell senescence (p16 and p21), nuclear double-strand DNA damage (γH2AX), autophagy (p62), and mtDNA damage (mtDNA copy number) in patients with BA who underwent Kasai portoenterostomy (KP) and LT. We studied liver biopsy specimens from 54 patients with BA, 14 who underwent LT and 11 from the livers of neonates and infants obtained at autopsy. In hepatocytes, p21 expression was significantly increased in KP. In cholangiocytes, p16 expression was significantly increased in LT, and p21 expression was significantly increased in KP. p62 expression was significantly increased in the KP hepatocytes and LT cholangiocytes. Furthermore, mtDNA copy number significantly decreased in KP and LT compared with the control. Cell senescence and mitochondrial DNA damage progression were dependent on the BA clinical stages and could possibly serve as the markers of indication of LT.

The Need for Early Kasai Portoenterostomy: A Western Pediatric Surgery Research Consortium Study

PURPOSE

The purpose of this study was to investigate factors impacting transplant-free survival among infants with biliary atresia.

METHODS

A multi-institutional, retrospective cohort study was performed at nine tertiary-level children's hospitals in the United States. Infants who underwent Kasai portoenterostomy (KP) from January 2009 to May 2017 were identified. Clinical characteristics included age at time of KP, steroid use, surgical approach, liver pathology, and surgeon experience. Likelihood of transplant-free survival (TFS) was evaluated using logistic regression, adjusting for patient and surgeon-level factors. Secondary outcomes at 1 year included readmission, cholangitis, reoperation, mortality, and biliary clearance.

RESULTS

Overall, 223 infants underwent KP, and 91 (40.8%) survived with their native liver. Mean age at surgery was 63.9 days (± 24.7 days). At 1 year, 78.5% experienced readmission, 56.9% developed cholangitis, 3.8% had a surgical revision, and 5 died. Biliary clearance at 3 months was achieved in 76.6%. Controlling for patient and surgeon-level factors, each additional day of age toward operation was associated with a 2% decrease in likelihood of TFS (OR 0.98, 95% CI 0.97-0.99).

CONCLUSION

Earlier surgical intervention by Kasai portoenterostomy at tertiary-level centers significantly increases likelihood for TFS. Policy-level interventions to facilitate early screening and surgical referral for infants with biliary atresia are warranted to improve outcomes.

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.

Hemodynamic analysis of hepatic arteries for the early evaluation of hepatic fibrosis in biliary atresia

BACKGROUND AND OBJECTIVE

Hepatic fibrosis is the prominent characteristic of biliary atresia (BA), may even progress continually after Kasai procedure (KP). BA, as a devastating pediatric hepatic disease, mainly leads to newborn cholestasis, even liver cirrhosis, eventually hepatic failure. Earlier diagnosis of hepatic fibrosis, which used to be detected by liver biopsy commonly, is consistent with better outcomes of KP. Due to potential risks and uncertainty of liver biopsy, it is an urge to seek a safer and more precise evaluation method as alternative. The purpose of this study is to investigate the hemodynamics of hepatic artery (HA) in hepatic fibrosis of early BA based on computational fluid dynamics (CFD) for evaluating the value of CFD for hepatic fibrosis diagnosis.

METHODS

40 patients were divided into three groups, including the control group, the abnormal liver function group and the mild to moderate hepatic fibrosis group. CFD was applied to quantify primary hemodynamic parameters of HA and related arteries, including blood flow distribution ratio (FDR), pressure, wall shear stress (WSS) and energy loss (EL). Statistical analyses were also performed to compare the differences amongst these above groups.

RESULTS

With the progression of hepatic fibrosis, the increasing tendency of hemodynamic parameters values of HA and related arteries were observed. Values of FDR, pressure, WSS and EL of the mild to moderate group was higher than those of the control group and the abnormal liver function group. There were significant differences on FDR_AA, FDR_HA and EL between the control group and the mild to moderate hepatic fibrosis group (t = 0.037, 0.030 and <0.001, P < 0.05).

CONCLUSION

Significant variations of HA hemodynamics acquired by CFD between the control group and the mild to moderate hepatic fibrosis group demonstrated the relationship between the progression of hepatic fibrosis and the hemodynamic disorder, and suggested that CFD had the potential to assist the diagnosis of hepatic fibrosis in early BA.

Chronic Drug-Induced Liver Injury: Updates and Future Challenges

Chronic drug-induced liver injury (DILI), defined as DILI with persistent liver injury more than one year after the first onset by the latest European guidelines, is a notable challenge globally with big issues of defining causality and establishing effective treatment. About 20% of patients with DILI develop into chronic DILI. Chronic DILI manifests as persistent or repeated inflammatory or diminishing bile ducts, even progresses to cirrhosis and needs liver transplantation eventually. However, research on chronic DILI over the last decades is still lacking, and the incidence, phenotypes, mechanisms, risk factors, and treatment have not been fully understood. In this paper, we reviewed the definition of chronic DILI, updated clinical studies in terms of incidence, special manifestations, and promising risk factors of chronic DILI, along with the recent progress and challenges in glucocorticoid therapy.

A novel mobile phone application for infant stool color recognition: An easy and effective tool to identify acholic stools in newborns

OBJECTIVES

Early diagnosis of biliary atresia is essential to improve long-term outcomes. Newborn screening with an infant stool color card allows early recognition of biliary atresia patients. Our aim was to develop and validate a mobile phone application (PopòApp) able to identify acholic stools.

METHODS

An intuitive app was developed for iOS and Android smartphones. A learning machine process was used to generate an algorithm for stools color recognition based on the seven colors of the infant stool color card, which were considered as the gold standard. Consecutive images of stools were taken by the PopòApp, directly into the diapers of children aged ≤6 months. The PopòApp classified the photographs as "normal", "acholic" or "uncertain". To validate the PopòApp, four doctors independently classified all images, and only those for which all doctors agreed were included. The sensitivity, specificity, positive/negative predictive values, and accuracy of the PopòApp were evaluated.

RESULTS

Of 165 images collected, 160 were included in the study. All acholic stools were recognized by the PopòApp. The PopòApp sensitivity was 100% (95% CI:93.9%-100%) with no false negatives, regardless of the brand of phone. The specificity was 99.0% (95% CI:94.6%-99.9%). The accurancy of the PopòApp was 99.4% (95% CI:96.6%-99.9%), with a positive predictive value of 98.4% (95% CI:89.8%-99.8%).

CONCLUSION

The current study proved, in a large cohort, that the PopòApp is an accurate and easy tool for recognition of acholic stools. The mobile App may represent an effective strategy for the early referral of children with acholic stools, and potentially could improve the outcomes of biliary atresia.

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

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

A Morphology-based Analysis of Biliary Ductules After Kasai Procedure and a Review of the Literature

OBJECTIVE

To explore the distribution of biliary ductules in biliary remnants of patients with biliary atresia and to investigate the relationship between the ductules and the prognosis after Kasai portoenterostomy.

PATIENTS AND METHODS

From October 01, 2015 to September 30, 2017, 46 patients who were diagnosed as type 3 biliary atresia were enrolled in this study. Continuous sections of biliary remnants were stained with cytokerantin 19 antibody. The number, area, and distribution of micro-biliary ductules of each section were recorded. According to the number of ductules in the most proximal section (n ≥ 20 or n < 20), patients were divided into two groups (A or B) and followed up for 1-3 y, including cholangitis, jaundice clearance, and survival with native liver.

RESULTS

Four patients had no micro-biliary ductules. In 17 patients with ductules, the numbers at bilateral parts were similar (P > 0.05), while the ductules in the middle part were significantly less than bilateral parts (P < 0.05). Starting from 2 mm from the proximal end of remnants, the number of ductules significantly and gradually decreased (P < 0.05). The total area of ductules in Group A was significantly increased compared to that in Group B (P < 0.05). Patients in Group A had significantly higher jaundice clearance rate and better survival rate with native liver than patients in Group B (both, P < 0.05). Patients had significantly higher incidence of cholangitis in Group A compared to Group B (P < 0.05).

CONCLUSIONS

The number/area of ductules yielded by technical precision is closely related to effective bile drainage, jaundice clearance, and first onset of cholangitis in patients after Kasai procedure.

Gene Expression Signatures Associated With Survival Times of Pediatric Patients With Biliary Atresia Identify Potential Therapeutic Agents

BACKGROUND & AIMS

Little is known about the factors that affect outcomes of patients with biliary atresia and there are no medical therapies that increase biliary drainage.

METHODS

Liver biopsies and clinical data were obtained from infants with cholestasis and from children without liver disease (controls); messenger RNA (mRNA) was isolated, randomly assigned to discovery (n = 121) and validation sets (n = 50), and analyzed by RNA sequencing. Using the Superpc R package followed by Cox regression analysis, we sought to identify gene expression profiles that correlated with survival without liver transplantation at 24 months of age. We also searched for combinations of gene expression patterns, clinical factors, and laboratory results obtained at diagnosis and at 1 and 3 months after surgery that associated with transplant-free survival for 24 months of age. We induced biliary atresia in BALB/c mice by intraperitoneal administration of Rhesus rotavirus type A. Mice were given injections of the antioxidants N-acetyl-cysteine (NAC) or manganese (III) tetrakis-(4-benzoic acid)porphyrin. Blood and liver tissues were collected and analyzed by histology and immunohistochemistry.

RESULTS

We identified a gene expression pattern of 14 mRNAs associated with shorter vs longer survival times in the discovery and validation sets (P < .001). This gene expression signature, combined with level of bilirubin 3 months after hepatoportoenterostomy, identified children who survived for 24 months with an area under the curve value of 0.948 in the discovery set and 0.813 in the validation set (P < .001). Computer models correlated a cirrhosis-associated transcriptome with decreased times of transplant-free survival; this transcriptome included activation of genes that regulate the extracellular matrix and numbers of activated stellate cells and portal fibroblasts. Many mRNAs expressed at high levels in liver tissues from patients with 2-year transplant-free survival had enriched scores for glutathione metabolism. Among mice with biliary atresia given injections of antioxidants, only NAC reduced histologic features of liver damage and serum levels of aminotransferase, gamma-glutamyl transferase, and bilirubin. NAC also reduced bile duct obstruction and liver fibrosis and increased survival times.

CONCLUSIONS

In studies of liver tissues from infants with cholestasis, we identified a 14-gene expression pattern that associated with transplant-free survival for 2 years. mRNAs encoding proteins that regulate fibrosis genes were increased in liver tissues from infants who did not survive for 2 years, whereas mRNAs that encoded proteins that regulate glutathione metabolism were increased in infants who survived for 2 years. NAC reduced liver injury and fibrosis in mice with biliary atresia, and increased survival times. Agents such as NAC that promote glutathione metabolism might be developed for treatment of biliary atresia.

Comparison of laparoscopic portoenterostomy and open portoenterostomy for the treatment of biliary atresia

BACKGROUND

Although open portoenterostomy (OPE) is considered the standard treatment for biliary atresia (BA), laparoscopic portoenterostomy (LPE) is conducted and reported by many investigators. Data on the safety and efficacy of LPE remain controversial. The aim of this meta-analysis is to compare the safety and efficacy of LPE and OPE for the treatment of BA.

METHODS

Three electronic databases were searched: PubMed, Embase, and the Cochrane Library. The eligible studies were limited to those published in English. The following keywords were used: "biliary atresia," "laparoscopic portoenterostomy," "Kasai portoenterostomy," "open portoenterostomy," "surgery," and "treatment."

RESULTS

Nine studies, including 434 patients, were analyzed. The operative time of LPE was significantly longer than that of OPE (MD = 40.55 min, 95% CI 4.83-76.27 min, P = 0.03). There was no significant difference between the two groups in terms of the time of hospital stay, the volume of intraoperative blood loss, or the rates of cholangitis, early clearance of jaundice or two-year survival with the native liver. The subgroup analyses revealed that the rate of early clearance of jaundice in the LPE group was significantly higher than that in the OPE group in studies published after 2016 (95% CI 1.04-1.75; P = 0.02).

CONCLUSIONS

The present meta-analysis provides evidence that LPE is a feasible option for patients with BA. LPE should be revaluated by further studies and longer follow-up.

Prominin-1 Promotes Biliary Fibrosis Associated With Biliary Atresia

In patients with biliary atresia (BA), the extent of intrahepatic biliary fibrosis negatively correlates with successful surgical bypass of the congenital cholangiopathy as well as subsequent transplant-free survival. We recently linked the expansion of a population of prominin-1 (Prom1)-expressing hepatic progenitor cells to biliary fibrogenesis. Herein, we hypothesized that Prom1-expressing progenitor cells play a role in BA-associated fibrosis. Rhesus rotavirus (RRV)-mediated experimental BA was induced in newborn mice homozygous for the transgene Prom1^{cre-ert2-nlacz} , which was knocked in to the Prom1 gene locus, thus creating functional Prom1 knockout (KO) mice, and their wildtype (WT) littermates. Clinical data and tissue samples from BA infants from the Childhood Liver Disease Research Consortium were analyzed. Extrahepatic biliary obliteration was present in both WT and KO mice; there was no difference in serum total bilirubin (TBili) levels. The intrahepatic periportal expansion of the PROM1^pos cell population, typically observed in RRV-induced BA, was absent in KO mice. RRV-treated KO mice demonstrated significantly fewer cytokeratin-19 (CK19)-positive ductular reactions (P = 0.0004) and significantly less periportal collagen deposition (P = 0.0001) compared with WT. RRV-treated KO mice expressed significantly less integrin-β6, which encodes a key biliary-specific subunit of a transforming growth factor (TGF) β activator (P = 0.0004). Infants with successful biliary drainage (Tbili ≤1.5 mg/dL within 3 months postoperatively), which is highly predictive of increased transplant-free survival, expressed significantly less hepatic PROM1, CK19, and COLLAGEN-1α compared with those with TBili >1.5 (P < 0.05). Conclusion: Prom1 plays an important role in biliary fibrogenesis, in part through integrin-mediated TGF pathway activation.

Transitional care for patients with surgical pediatric hepatobiliary disease: Choledochal cysts and biliary atresia

Choledochal cysts (CDCs) and biliary atresia (BA) are rare pediatric hepatobiliary anomalies that require surgical intervention due to increased risk of malignancy and liver failure, respectively. The underlying disease and operative procedures place patients at risk for long-term complications, which may continue to affect them into adulthood. Lack of a transitional care model in the health-care system potentiates the challenges they will face following aging out of their pediatric providers' care. We sought to elucidate the long-term complications and challenges patients with CDCs and BA face, review the current literature regarding transitioning care, and propose guidelines aiding adult providers in continued care and surveillance of these patients. A literature review was performed to assess short-term and long-term complications after surgery and the current standards for transitioning care in patients with a history of CDCs and BA. While transitional programs exist for patients with other gastrointestinal diseases, there are few that focus on CDCs or BA. Generally, authors encourage medical record transmission from pediatric to adult providers, ensuring accuracy of information and compliance with treatment plans. Patients with CDCs are at risk for developing biliary malignancies, cholangitis, and anastomotic strictures after resection. Patients with BA develop progressive liver failure, necessitating transplantation. There are no consensus guidelines regarding timing of follow up for these patients. Based on the best available evidence, we propose a schema for long-term surveillance.

Gene expression profile of TLR7 signaling pathway in the liver of rhesus rotavirus-induced murine biliary atresia

PURPOSE

To identify genes potentially involved in the pathogenesis of bile duct obstruction in biliary atresia (BA).

METHODS

We used rhesus rotavirus (RRV) Balb/c mouse BA model to study BA. Liver and serum samples were harvested from BA and normal control (NC) groups at 1, 3, 5, 7, 10 and 14 days postinoculation. Serum total bilirubin (STB) and conjugated bilirubin (CB) were measured. Livers of each group at day 7 were used for a genome-wide expression analysis. Expression of TLR7 signaling pathway in liver was measured by immunohistochemical staining and western blotting, including expression of TLR7, activation of phosphorylated IRF7 and secretion of IFN-β, IL-1α and IL-6. Cell viability and survival rate after RRV infection were measured by using TLR7 knockdown human cholangiocarcinoma cell RBE.

RESULTS

STB was significantly elevated from day 5 postinoculation and CB was from day 7 postinoculation, while CK19 (the biomarker of biliary epithelial cells) expression by western blotting was decreased. By microarray analysis of liver tissues at day 7 postinoculation, TLR7 signaling pathway was up-regulated in BA mice. Based on the results of microarray analysis, the protein expression of TLR7 in the liver tissues of BA groups were found to be up-regulated from day 5 comparing to respective NC groups, although it was increased as pups aged in NC groups. And the level of p-IRF7 and secretion of cytokines were also statistically significant in BA groups. In vitro, TLR7 knockdown cell line showed less cellular proliferation and more susceptible to RRV infection.

CONCLUSION

By in vivo study, TLR7 signal pathway was up-regulated in BA group; by additional in vitro study, intact TLR7 signal pathway might have some protective abilities in BA pathogenesis.

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.

Development and Validation of Novel Diagnostic Models for Biliary Atresia in a Large Cohort of Chinese Patients

Background & aims

The overlapping features of biliary atresia (BA) and the other forms of neonatal cholestasis (NC) with different causes (non-BA) has posed challenges for the diagnosis of BA. This study aimed at developing new and better diagnostic models for BA.

Methods

We retrospectively analyzed data from 1728 newborn infants with neonatal obstructive jaundice (NOJ). New prediction models, including decision tree (DT), random forest (RF), and multivariate logistic regression-based nomogram for BA were created and externally validated in an independent set of 508 infant patients.

Results

Fiver predictors, including gender, weight, direct bilirubin (DB), alkaline phosphatase (ALP), and gamma-glutamyl transpeptidase (GGT) were significantly different between the BA and non-BA groups (P < .05), from which DT, RF, and nomogram models were developed. The area under the receiver operating characteristic (ROC) curve (AUC) value for the nomogram was 0.898, which was greater than that of a single biomarker in the prediction of BA. Performance comparison of the three diagnostic models showed that the nomogram displayed better discriminative ability (sensitivity, 85.7%; specificity, 80.3%; PPV, 0.969) at the optimal cut-off value compared with DT and RF, which had relatively similar high sensitivity and PPV (0.941 and 0.947, respectively), but low specificity in the modeling group. In sub-analysis of the discriminative capacity between the nomogram and GGT (<300 or ≥ 300), we found that the nomogram was superior to the GGT alone in the preoperative diagnosis of BA.

Conclusions

The nomogram has demonstrated better performance for the prediction of BA, holding promise for future clinical application.

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A novel nomogram has been established for prediction of biliary atresia (BA).

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Its discriminatory ability is significantly improved compared with GGT alone.

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It holds promise for clinical application for better diagnosis of BA.

Association of T-helper cell cytokine level with age in patients with biliary atresia: a preliminary study

BACKGROUND

The pathogenesis of biliary atresia (BA) is associated with an inflammatory process involving the biliary tree. This study aimed to investigate the association of T-helper cell cytokine levels with age in patients with BA.

METHODS

Twenty-eight patients with BA were divided into three groups according to their age (< 2 months, 2-3 months, and ≥ 3 months). All the patients underwent Kasai portoenterostomy. Blood samples were collected from the patients preoperatively, and the liver tissue specimens were obtained during surgery. We detected serum levels of interleukin (IL)-1β, IL-12p70, interferon (IFN)-γ, IL-6, IL-10, and transforming growth factor (TGF)-β1 and liver expression of IL-1β, IL-6, and TGF-β1.

RESULTS

The serum levels of IL-1β, IL-12p70, IL-6, and IL-10 in patients aged ≥ 3 months were significantly higher than those in patients aged < 2 months. There were no significant age-related differences in the IL-1β, IL-6 and TGF-β1 expression levels in the liver tissue of patients with BA.

CONCLUSIONS

The serum levels of IL-1β, IL-6, IL-10 and IL-12p70 showed significant age-related differences in patients with BA. Interpretation of the role of cytokines in BA needs to take patient's age into consideration.

Kasai procedure improves nutritional status and decreases transplantation-associated complications

BACKGROUND

The aim of this study was to retrospectively investigate whether Kasai Procedure (KP) improves nutritional status and whether KP decreases liver transplantation (LT)-associated complications in children with biliary atresia (BA).

METHODS

From March 1st 2014 to February 28th 2015, 103 patients underwent LT and the other 17 without prior KP died during the waiting period. In 103 patients undergoing LT, 58 patients received KP previously (Group A), and 45 only underwent primary LT (Group B). The nutritional status, liver function and LT-related short-term complications were analyzed.

RESULTS

Compared to Group B, patients in Group A had significantly increased time interval when undergoing LT (p < 0.05). Persistently, the bodyweight, albumin and hemoglobin in Group A were significantly increased compared to Group B (all, p < 0.0001). The bilirubin, ALT/AST and PELD score in Group A were all decreased compared to Group B (p < 0.05) prior to LT. The incidences of post-LT severe infection and hypoalbuminemia in Group A were significantly lower than those of Group B (p < 0.05).

CONCLUSIONS

KP improves the nutritional status, preserves liver function for patients who finally undergo LT, and decreases the incidence post-LT severe infection and hypoalbuminemia. Mental health can be improved in parents whose children underwent previous KP.

Liver transplantation for biliary atresia: a systematic review

Biliary atresia (BA) is an idiopathic neonatal cholangiopathy characterized by progressive inflammatory obliteration of the intrahepatic or extrahepatic bile ducts. Although the Kasai operation has dramatically improved the outcomes in children with BA, most patients with BA eventually require liver transplantation (LT) even after undergoing a successful Kasai procedure. The Japanese LT Society (JLTS) was established in 1980 to characterize and follow trends in patient characteristics and the graft survival among all liver transplant patients in Japan. The 1-, 5-, 10-, 15- and 20-year survival rates for the patients and grafts undergoing living donor LT were 91.6, 91.5, 87.1, 85.4 and 84.2 and 90.5, 90.4, 84.6, 82.0 and 79.9%, respectively. LDLT was able to be performed even in patients weighing less than 5 kg with early liver failure following a Kasai operation using a reduced left lateral segments. As LT has been revealed to increase the donor pool and decrease the waiting list mortality with an excellent long-term graft survival, early referral to a transplant center should be considered when at least one complication of cirrhosis occurs during its natural history, especially in adolescents.

Expression of programmed death-1 and its ligands in the liver of biliary atresia

BACKGROUND

An aberrant immune response is the predominant pathogenetic factor in biliary atresia (BA). Programmed death-1 (PD-1) and its two ligands, programmed death ligand-1 and programmed death ligand-2 (PD-L1 and PD-L2, respectively) play an important inhibitory role in immune reactions. We aimed to illustrate the expression of these molecules in BA.

METHODS

Liver specimens were obtained from infants with BA during the Kasai procedure (early BA) and liver transplantation (late BA). Intrahepatic expression of PD- 1, PD-L1, and PD-L2 were examined by immunostaining and compared with that in patients with neonatal hepatitis syndrome and normal controls. The correlation between the expression levels of these molecules in the liver and clinicopathological parameters was analyzed for each group.

RESULTS

Enhanced expression of PD-1 and its ligands occurred in the livers with early BA. In the BA-affected livers, PD-1 was correlated with the degree of peri-biliary inflammation, while PD-L2 was linked more directly with portal fibrosis. None of the three molecules was correlated with the prognosis of the Kasai procedure in patients with early BA.

CONCLUSIONS

Only PD-1 and PD-L1 are involved in the immune reactions of early BA. Elucidation of the detailed role of PD-L2 in BA requires further research.

Newborn screening for biliary atresia in the United States

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

Living donor liver transplantation for post-Kasai biliary atresia: Analysis of pretransplant predictors of outcomes in infants

After decades of dramatic surgical innovations in pediatric living donor liver transplantation (LDLT), LDLT for biliary atresia (BA) still poses various challenges. This study reviewed our experience with LDLT for children with post-Kasai BA and evaluated outcomes and prognostic factors. From 2005 to 2016, 168 post-Kasai BA LDLT patients were enrolled and divided into 3 groups by age. Patient characteristics and perioperative data were compared. Predictors of morbidity and mortality following LDLT were analyzed in 93 infants. Outcome was relatively worse in infants than older children, with overall survival at 1 and 5 years of 94.5% and 93.2%, respectively, and graft survival at 1 and 5 years of 91.1% each. Incidence of vascular complications was not significantly higher in infants. High Pediatric End-Stage Liver Disease (PELD) score (odds ratio [OR], 3.72; 95% confidence interval [CI], 1.30-10.67; P = 0.02) and portal vein (PV) hypoplasia (OR, 3.23; 95% CI, 1.10-9.52; P = 0.03) were independent risk factors for morbidity. Low weight-for-age z score (hazard ratio, 5.76; 95% CI, 1.05-31.47; P = 0.03) was identified as a significant risk factor for mortality after LDLT, but not age or absolute body weight (BW). Infants with BW deficit had a significantly smaller PV diameter (P = 0.005), greater blood loss (P = 0.001), and higher incidence of postoperative bacteremia (P = 0.01). In conclusion, high PELD score and PV hypoplasia were independent risk factors for morbidity, and BW deficit was associated with poor survival in infants with post-Kasai BA after LDLT. However, LDLT in these infants at the earliest possible time after referral is a feasible option with excellent patient survival in an experienced center. Liver Transplantation 23 1199-1209 2017 AASLD.

Contemporary Evaluation of the Pediatric Liver Biopsy

Liver disease in the neonate, infant, child, and adolescent may manifest differently depending on the type of disorder. These disorders show marked overlap clinically and on light microscopy. Histology and ultrastructural examination are used in tandem for the diagnosis of most disorders. A final diagnosis or interpretation of the pediatric liver biopsy depends on appropriate and adequate clinical history, laboratory test results, biochemical assays, and molecular analyses, as indicated by the light microscopic and ultrastructural examination.

Forkhead box A3 attenuated the progression of fibrosis in a rat model of biliary atresia

Biliary atresia is a rare, devastating disease of infants where a fibroinflammatory process destroys the bile ducts, leading to fibrosis and biliary cirrhosis, and death if untreated. The cause and pathogenesis remain largely unknown. We tried to investigate factors involved in biliary atresia, especially forkhead box A3 (Foxa3), which might exert a role in the treatment of liver disease. We used RNA sequencing to sequence the whole transcriptomes of livers from six biliary atresia and six choledochal cysts patients. Then, we employed a rat disease model by bile duct ligation (BDL) and adenovirus transduction to address the function of Foxa3 in biliary atresia. We found that tight junction, adherence junction, cell cycle, apoptosis, chemokine singling, VEGF and MAPK signaling pathways were enriched in biliary atresia livers. We showed that Foxa3 expression was notably decreased in liver samples from biliary atresia patients. More importantly, we found that its lower expression predicted a poorer overall survival of biliary atresia patients. Rats that received BDL surgery and Foxa3 expression adenovirus resulted in a significant decrease in the deposition of collagen, and expression of profibrotic cytokines (transforming growth factor-β and connective tissue growth factor) and fibrosis markers (α-smooth muscle actin, collagen I and collagen III), as compared with rats that received BDL surgery and control adenovirus. Our data suggested a protection role for Foxa3 during the progression of liver fibrosis in biliary atresia, and thereby supported increasing Foxa3 as a targeted treatment strategy.

Hepatic Prominin-1 expression is associated with biliary fibrosis

BACKGROUND

Intrahepatic biliary fibrosis, as seen with cholestatic liver injuries such as biliary atresia, is mechanistically distinct from fibrosis caused by hepatocyte toxicity. We previously demonstrated the expansion of cells expressing the stem/progenitor cell marker Prominin-1, within regions of developing fibrosis in biliary atresia. Thus, we hypothesized that Prominin-1 expression is biliary fibrosis-specific.

METHODS

Gene expression of Prominin-1 was analyzed in adult mice undergoing either cholestatic bile duct ligation or hepatotoxic carbon tetrachloride administration by quantitative polymerase chair reaction. Lineage tracing of Prominin-1-expressing cells and Collagen-1α-expressing cells was performed after bile duct ligation in Prominin-1^{cre-ert2-lacz};Gfp^lsl and Collagen-1α^Gfp transgenic mice, respectively.

RESULTS

Prominin-1 expression increased significantly after bile duct ligation compared with sham (6.6 ± 0.9-fold change at 2 weeks, P < .05) but not with carbon tetrachloride (-0.7 ± 0.5-fold change, not significant). Upregulation of Prominin-1 was observed histologically throughout the liver as early as 5 days after bile duct ligation in Prominin-1^{cre-ert2-lacz} mice by LacZ staining in nonhepatocyte cells. Lineage tracing of Prominin-1-expressing cells labeled prior to bile duct ligation in Prominin-1^{cre-ert2-lacz};Gfp^lsl mice, demonstrated increasing colocalization of GREEN FLUORESCENT PROTEIN with biliary marker CYTOKERATIN-19 within ductular reactions up to 5 weeks after bile duct ligation consistent with biliary transdifferentiation. In contrast, rare colocalization of GREEN FLUORESCENT PROTEIN with mesenchymal marker α-SMOOTH MUSCLE ACTIN in Prominin-1^{cre-ert2-lacz};Gfp^lsl mice and some colocalization of GREEN FLUORESCENT PROTEIN with PROMININ-1 in Collagen-1α^Gfp mice, indicate minimal contribution of Prominin-1 progenitor cells to the pool of collagen-producing myofibroblasts.

CONCLUSION

During biliary fibrosis Prominin-1-expressing progenitor cells transdifferentiate into cells within ductular reactions. This transdifferentiation may promote fibrosis.

Achondroplasia and Biliary Atresia: A Rare Association and Review of Literature

Achondroplasia (ACH) occurs in most cases as de novo mutations of the gene-encoding fibroblast growth factor receptor 3 (FGFR3). Biliary atresia (BA) is a progressive neonatal inflammatory and fibro-obliterative cholangiopathy affecting the extra- and intrahepatic biliary tree to varying degrees, and it results in obstruction to bile flow and cholestatic jaundice in neonates. BA is thought to be a multifactorial disease, genome association studies have shown abnormalities in susceptibility genes, and levels of fibroblast growth factor 21 (FGF21) and fibroblast growth factor 23 (FGF23) have been noted to be increased. These two conditions occurring in the same patient has never been reported before.

Association between rs17095355 polymorphism on 10q24 and susceptibility to biliary atresia: a meta-analysis

OBJECTIVE

Recent studies have identified 10q24-rs17095355 as a susceptibility locus for biliary atresia (BA). To more precisely estimate the association between the rs17095355 polymorphism and BA risk, a meta-analysis was performed.

METHODS

A comprehensive search was conducted to examine all the eligible studies by electronic databases including Elsevier Science Direct, Pubmed, Google Scholar, China National Knowledge Infrastructure (CNKI) and Chinese Biomedical Literature (CBM) up to December 2015. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated to assess the strength of the association.

RESULTS

A total of 6 comparisons from 5 relevant studies involving 1000 patients and 3257 controls were included to analyze the association between rs17095355 and BA risk. The pooled OR for T allele of rs17095355 was 1.72 (95%CI 1.53-1.92, p < 0.01) in BA. Stratification by ethnicity indicated the degree of risk of rs17095355 with BA susceptibility was similar in populations of Asian origin. The pooled OR was 1.81 (95%CI 1.60-2.06, p < 0.01).

CONCLUSIONS

This meta-analysis confirms the association of rs17095355 polymorphism and BA development, especially in Asians. More original studies with large sample are needed to replicate this genetic association in different ethnic groups.

Serum microRNA microarray analysis identifies miR-4429 and miR-4689 are potential diagnostic biomarkers for biliary atresia

This study aimed to investigate pathogenesis and novel diagnostic biomarkers of biliary atresia (BA). Serum samples from infants with BA and non-BA neonatal cholestasis (NC) were collected for miRNA microarray analysis, and then differentially expressed miRNAs were screened. Differentially expressed miRNAs were validated by qRT-PCR using an independent serum samples from infants with BA and NC. Diagnostic utility of validated miRNAs was further analyzed using serum samples by receiver-operating characteristic curve analysis. Totally, 13 differentially expressed miRNAs were identified including 11 down-regulated and 2 up-regulated ones. Target genes of hsa-miR-4429 and hsa-miR-4689 were significantly involved in FoxO signaling pathway. Eight differentially expressed miRNAs were chosen for validation by qRT-PCR analysis, and four miRNAs (hsa-miR-150-3p, hsa-miR-4429, hsa-miR-4689 and hsa-miR-92a-3p) were differentially expressed. The area under the curve of hsa-miR-4429 and hsa-miR-4689 was 0.789 (sensitivity = 83.33%, specificity = 80.00%) and 0.722 (sensitivity = 66.67%, specificity = 80.00%), respectively. Differentially expressed miRNAs including hsa-miR-4429 and hsa-miR-4689 might play critical roles in BA by regulating their target genes, and these two miRNAs may have the potential to become diagnostic biomarkers.