Human Liver Organoids to Predict the Outcome of Kasai Portoenterostomy.

BACKGROUND: Kasai portoenterostomy (KPE) remains the primary intervention for biliary atresia (BA), but its outcomes are highly variable. Reliable prognostic biomarkers remain elusive, complicating the management and prediction of postoperative progression. METHOD: Liver biopsies from BA patients taken at and after KPE (post-KPE) were used to generate organoids for RNA-sequencing analysis. Control organoids were derived from non-BA livers. Differential gene expression and enrichment analyses were performed to assess post-KPE transcriptomic changes between native liver survivors (NLS) and patients who eventually became liver transplant recipients (LTR). RESULTS: Organoid datasets: 70 from liver biopsies at KPE (10 patients), 112 from post-KPE livers (13 livers; 12 patients), and 47 from control livers (9 patients). At KPE, BA organoids displayed mainly hepatocyte expression, a trait notably reduced in control organoids. Similarly, post-KPE organoids from NLS revealed a significant decrease in hepatocyte expression features and an overall increase in cholangiocyte expression features. A similar hepatocyte-to-cholangiocyte expression transition was evidenced in paired liver organoids (at- and post-KPE) generated from an NLS. In contrast, post-KPE organoids from LTR maintained a high level of hepatocyte expression features. CONCLUSION: Our study demonstrated that an elevated expression of hepatocyte features in KPE organoids may indicate aberrant cholangiocyte development in BA livers. In contrast, a post-KPE hepatocyte-to-cholangiocyte expression transition in NLS may imply effective biliary recovery. The lack of this transition in LTR organoids indicates ongoing disease progression, highlighting the potential for organoid-based transcriptomic profiling to inform KPE success and guide BA management. LEVEL OF EVIDENCE: Level III.

Animal and organoid models to elucidate the anti-fibrotic effect of steroid on biliary atresia.

PURPOSE: We performed animal and organoid study to evaluate the anti-fibrotic effect of steroid on biliary atresia (BA) and the underlying patho-mechanism. METHODS: BA animal models were created by inoculation of mice on post-natal day 1 with rhesus rotavirus (RRV). They received either 20 µl phosphate-buffered saline (PBS) or steroid from day 21 to day 34. On day 34, their serum samples were collected for hormonal markers. Necrosis, fibrosis and CK 19 expression in the liver were evaluated. Liver organoids were developed and their morphology as well as bulk RNA sequencing data were analyzed. RESULTS: Twenty-four mice developed BA features after RRV injection and were equally divided into steroid and PBS groups. On day 34, the weight gain of steroid group increased significantly than PBS group (p < 0.0001). All mice in the PBS group developed liver fibrosis but only one mouse in the steroid group did. Serum bilirubin and liver parenchymal enzymes were significantly lower in steroid group. The morphology of liver organoids were different between the two groups. A total of 6359 differentially expressed genes were found between steroid group and PBS group. CONCLUSION: Based on our findings obtained from RRV-induced BA animal and organoid models, steroid has the potential to mitigate liver fibrosis in BA.

Biliary atresia.

Biliary atresia (BA) is a progressive inflammatory fibrosclerosing disease of the biliary system and a major cause of neonatal cholestasis. It affects 1:5,000-20,000 live births, with the highest incidence in Asia. The pathogenesis is still unknown, but emerging research suggests a role for ciliary dysfunction, redox stress and hypoxia. The study of the underlying mechanisms can be conceptualized along the likely prenatal timing of an initial insult and the distinction between the injury and prenatal and postnatal responses to injury. Although still speculative, these emerging concepts, new diagnostic tools and early diagnosis might enable neoadjuvant therapy (possibly aimed at oxidative stress) before a Kasai portoenterostomy (KPE). This is particularly important, as timely KPE restores bile flow in only 50-75% of patients of whom many subsequently develop cholangitis, portal hypertension and progressive fibrosis; 60-75% of patients require liver transplantation by the age of 18 years. Early diagnosis, multidisciplinary management, centralization of surgery and optimized interventions for complications after KPE lead to better survival. Postoperative corticosteroid use has shown benefits, whereas the role of other adjuvant therapies remains to be evaluated. Continued research to better understand disease mechanisms is necessary to develop innovative treatments, including adjuvant therapies targeting the immune response, regenerative medicine approaches and new clinical tests to improve patient outcomes.

Environmental Toxin Biliatresone-Induced Biliary Atresia-like Abnormal Cilia and Bile Duct Cell Development of Human Liver Organoids.

Biliary atresia (BA) is a poorly understood and devastating obstructive bile duct disease of newborns. Biliatresone, a plant toxin, causes BA-like syndrome in some animals, but its relevance in humans is unknown. To validate the hypothesis that biliatresone exposure is a plausible BA disease mechanism in humans, we treated normal human liver organoids with biliatresone and addressed its adverse effects on organoid development, functions and cellular organization. The control organoids (without biliatresone) were well expanded and much bigger than biliatresone-treated organoids. Expression of the cholangiocyte marker CK19 was reduced, while the hepatocyte marker HFN4A was significantly elevated in biliatresone-treated organoids. ZO-1 (a tight junction marker) immunoreactivity was localized at the apical intercellular junctions in control organoids, while it was markedly reduced in biliatresone-treated organoids. Cytoskeleton F-actin was localized at the apical surface of the control organoids, but it was ectopically expressed at the apical and basal sides in biliatresone-treated organoids. Cholangiocytes of control organoids possess primary cilia and elicit cilia mechanosensory function. The number of ciliated cholangiocytes was reduced, and cilia mechanosensory function was hampered in biliatresone-treated organoids. In conclusion, biliatresone induces morphological and developmental changes in human liver organoids resembling those of our previously reported BA organoids, suggesting that environmental toxins could contribute to BA pathogenesis.

Does the Choice of Suture Materials Affect the Vas Deferens after Hernia Ring Closure in Inguinal Hernia Surgery: An Experimental Study in Rats.

INTRODUCTION: Laparoscopic inguinal hernia repair is a commonly performed procedure in children. Currently, monofilament polypropylene and braided silk are the two most frequently used materials. Studies have suggested more tissue inflammatory reactions with the use of multifilament non-absorbable sutures. However, little is known about the effects of suture materials on adjacent vas deferens. The aim of this experiment was to compare the effect of non-absorbable monofilament and multifilament sutures on vas deferens in laparoscopic hernia repair. METHODS: All animal operations were performed by a single surgeon under aseptic conditions and anaesthesia. Ten male Sprague Dawley rats were divided into two groups. In Group I, "hernia repair" was performed using 5.0 Silk. In Group II, polypropylene sutures (Prolene®; Ethicon, Somerville, N.J., USA) were used. All animals also received sham operations in the left groin as a control. After 14 days, the animals were euthanised and a segment of vas deferens just adjacent to the suture was excised for histological review by an experienced pathologist who was blind to the treatment groups of the respective specimens. RESULTS: The body sizes of the rats in each group were comparable. Group I had significantly smaller vas deferens than Group II (diameter: 0.2 vs. 0.6 ± 0.2, p = 0.005). Silk sutures appeared to cause more tissue adhesion than Prolene® sutures, as graded by blind assessors (adhesion grade: 2.8 ± 1.3 vs. 1.8 ± 0.8, p = 0.1), although this did not reach statistical significance. There was no significant difference in the histological fibrosis score and inflammation score. CONCLUSION: The only effect of non-absorbable sutures on vas deferens in this rat model was the reduced cross-sectional area of vas deferens and increased tissue adhesion when using silk sutures. However, there was no significant histological difference in inflammation or fibrosis caused by either material.

Identification of cancer-related genes FGFR2 and CEBPB in choledochal cyst via RNA sequencing of patient-derived liver organoids.

BACKGROUND: Choledochal cysts (CC) are congenital bile duct anomalies with 6-30% risk for developing bile duct cancer. However, the molecular mechanisms underlying cancer risk of CC are unknown. We sought to identify the gene expression changes underlying the cancer risk of CC patients. METHODS: Liver organoids (n = 51) were generated from liver/bile duct biopsies of CC (n = 7; type I) and hepatoblastoma (n = 5; HB: non-tumor & tumor) for RNA sequencing. Bioinformatics analysis was conducted to identify differentially expressed cancer-related genes in CC and controls. We compared CC with non-cancerous and cancerous controls, normal adjacent non-tumor region of hepatoblastoma (HB) liver as non-cancerous control and tumor region as non-CC cancer control (HB-tumor). Reverse transcription real-time quantitative PCR (RT-qPCR) verification and immunohistochemistry of selected genes was conducted in additional CC and HB liver biopsies. FINDINGS: HB non-tumor and HB tumor organoids displayed distinct gene expression profiles. Expression profiling separated CC organoids into two clusters, one overlapping with HB non-tumor and the other one with HB tumor organoids. Genes selected based on their log2FoldChange values for RT-qPCR verification in 31 CC and 11 HB non-tumor liver tissues revealed significantly elevated expression of FGFR2 in 7 and CEBPB in 2 CC liver tissues (CC vs HB: 4.082 vs. 0.7671, p<0.01; 2.506 vs. 1.210, p<0.01). Distinctive positive staining in bile ducts were seen in CC, HB tumor and non-tumor liver tissues for FGFR2 and CEBPB. Percentages of CEBPB-immuno-positive or FGFR2-immuno-positive bile duct cells in CC and HB-tumor liver were higher than that in HB non-tumor liver. INTERPRETATION: The study identified dysregulated genes related to cancer pathways in CC patients suggesting cancer risk. The findings suggest that the elevated expression of FGFR2 and CEBPB in liver may contribute to cancer development in CC patients.

Temporal and spatial development of intestinal smooth muscle layers of human embryos and fetuses.

The sequential occurrence of three layers of smooth muscle layers (SML) in human embryos and fetus is not known. Here, we investigated the process of gut SML development in human embryos and fetuses and compared the morphology of SML in fetuses and neonates. The H&E, Masson trichrome staining, and Immunohistochemistry were conducted on 6-12 gestation week human embryos and fetuses and on normal neonatal intestine. We showed that no lumen was seen in 6-7th gestation week embryonic gut, neither gut wall nor SML was developed in this period. In 8-9th gestation week embryonic and fetal gut, primitive inner circular SML (IC-SML) was identified in a narrow and discontinuous gut lumen with some vacuoles. In 10th gestation week fetal gut, the outer longitudinal SML (OL-SML) in gut wall was clearly identifiable, both the inner and outer SML expressed α-SMA. In 11-12th gestation week fetal gut, in addition to the IC-SML and OL-SML, the muscularis mucosae started to develop as revealed by α-SMA immune-reactivity beneath the developing mucosal epithelial layer. Comparing with the gut of fetuses of 11-12th week of gestation, the muscularis mucosae, IC-SML, and OL-SML of neonatal intestine displayed different morphology, including branching into glands of lamina propria in mucosa and increased thickness. In conclusions, in the human developing gut between week-8 to week-12 of gestation, the IC-SML develops and forms at week-8, followed by the formation of OL-SML at week-10, and the muscularis mucosae develops and forms last at week-12.

Bioengineering Liver Organoids for Diseases Modelling and Transplantation.

Organoids as three-dimension (3D) cellular organizations partially mimic the physiological functions and micro-architecture of native tissues and organs, holding great potential for clinical applications. Advances in the identification of essential factors including physical cues and biochemical signals for controlling organoid development have contributed to the success of growing liver organoids from liver tissue and stem/progenitor cells. However, to recapitulate the physiological properties and the architecture of a native liver, one has to generate liver organoids that contain all the major liver cell types in correct proportions and relative 3D locations as found in a native liver. Recent advances in stem-cell-, biomaterial- and engineering-based approaches have been incorporated into conventional organoid culture methods to facilitate the development of a more sophisticated liver organoid culture resembling a near to native mini-liver in a dish. However, a comprehensive review on the recent advancement in the bioengineering liver organoid is still lacking. Here, we review the current liver organoid systems, focusing on the construction of the liver organoid system with various cell sources, the roles of growth factors for engineering liver organoids, as well as the recent advances in the bioengineering liver organoid disease models and their biomedical applications.

Embryology and anatomy of Hirschsprung disease.

Bowel has its own elegant nervous system - the enteric nervous system (ENS) which is a complex network of neurons and glial clones. Derived from neural crest cells (NCCs), this little brain controls muscle contraction, motility, and bowel activities in response to stimuli. Failure of developing enteric ganglia at the distal bowel results in intestinal obstruction and Hirschsprung disease (HSCR). This Review summarises the important embryological development of the ENS including proliferation, migration, and differentiation of NCCs. We address the signalling pathways which determine NCC cell fate and discuss how they are altered in the context of HSCR. Finally, we outline the anatomical defects and the mechanisms underlying gut motility in HSCR.

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 (Aß) around hepatic bile ducts has been discovered as a factor for BA pathogenesis, yet whether plasma Aß 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, Aß40 and Aß42 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 Aß42/Aß40 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 Aß42/Aß40 for BA. Diagnostic enhancement was further evaluated by binary regression ROC analysis of Aß42/Aß40 combined with other hepatic function parameters. Results: Plasma Aß42/Aß40 was elevated in BA patients. Aß42 displayed a weak positive correlation with γ-glutamyl transpeptidase (GGT) (Pearson's correlation = 0.349), while there was no correlation for Aß40 with hepatic functions. Aß42/Aß40 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). Aß42/Aß40 showed an acceptable predictive power for cholestasis [AUC = 0.746 (95% CI: 0.552-0.941), p < 0.05]. Diagnostic powers of Aß42/Aß40 together with hepatic function parameters for cholestasis were markedly improved compared to any indicator alone. Neither Aß42/Aß40 nor hepatic function parameters displayed sufficient power in discriminating BA from choledochal cysts (CC); however, combinations of Aß42/Aß40 + 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: Aß42/Aß40 is a good indicator for cholestasis, but alone is insufficient for a distinction of BA from non-BA. However, Aß42/Aß40 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.

CD177+ cells produce neutrophil extracellular traps that promote biliary atresia.

BACKGROUND & AIMS: We have previously reported on the potential pathogenic role of neutrophils in biliary atresia (BA). Herein, we aimed to delineate the role of CD177+ neutrophils in the pathogenesis of BA. METHODS: Immune cells from the livers of mice with rhesus rotavirus-induced BA were analysed. Single-cell RNA-sequencing was performed to specifically analyse Gr-1+ (Ly6C/Ly6G+) cells in the liver. Gene expression profiles of CD177+ cells were analysed using the Smart-Seq RNA-sequencing method, and the pathogenesis of BA was examined in Cd177-/- mice. Neutrophil extracellular trap (NET) inhibitors were used to determine the role of CD177+ cell-derived NETs in BA-associated bile duct damage, and a pilot clinical study evaluated the potential effects of N-acetylcysteine on NET release in BA. RESULTS: Increased levels of Gr-1+ cells were observed in the livers of mice with rhesus rotavirus-induced BA. RNA-sequencing analysis revealed that CD177+ cells were the main population of Gr-1+ cells and expressed elevated levels of both interferon-stimulated and neutrophil degranulation genes. Cd177-/- BALB/c mice exhibited delayed disease onset and reduced morbidity and mortality. High numbers of mitochondria were detected in CD177+ cells derived from mice with BA; these cells were associated with increased levels of reactive oxygen species and increased NET formation, which induced the apoptosis of biliary epithelial cells in cocultures. In a pilot clinical study, the administration of N-acetylcysteine to patients with BA reduced CD177+ cell numbers and reactive oxygen species levels, indicating a potential beneficial effect. CONCLUSIONS: Our data indicate that CD177+ cells play an important role in the initiation of BA pathogenesis via NET formation. CLINICAL TRIAL REGISTRATION: The pilot study of N-acetylcysteine treatment in patients with BA was registered on the Chinese Clinical Trial Registry (ChiCTR2000040505). LAY SUMMARY: Neutrophils (a type of innate immune cell, i.e. an immune cell that doesn't target a specific antigen) are thought to play a role in the development of biliary atresia (a rare but potentially lethal condition of the bile ducts that occurs in infants). Herein, we found that neutrophils expressing a particular protein (CD177) played an important role in bile duct damage by releasing a special structure (NET) that can trap and kill pathogens but that can also cause severe tissue damage. A pilot study in patients with biliary atresia showed that inhibiting NETs could have a beneficial effect.

Pathogenesis of Choledochal Cyst: Insights from Genomics and Transcriptomics.

Choledochal cysts (CC) is characterized by extra- and/or intra-hepatic b\ile duct dilations. There are two main theories, "pancreaticobiliary maljunction" and "congenital stenosis of bile ducts" proposed for the pathogenesis of CC. Although family cases or CC associated with other anomalies have been reported, the molecular pathogenesis of CC is still poorly understood. Recent advances in transcriptomics and genomics analysis platforms have unveiled key expression signatures/genes/signaling pathways in the pathogenesis of human diseases including CC. This review summarizes insights from genomics and transcriptomics studies into the pathogenesis of CC, with the aim to improve (i) our understanding of its underlying complex pathomechanisms, and (ii) clinical management of different subtypes of CC, in particular their associated hepatic fibrotic change and their risk of malignancy transformation.

Developing Biliary Atresia-like Model by Treating Human Liver Organoids with Polyinosinic:Polycytidylic Acid (Poly (I:C)).

Background: We explored the feasibility of creating BA-like organoids by treating human liver organoids with Polyinosinic:Polycytidylic acid (Poly I:C). Methods: Organoids were developed from the liver parenchyma collected during Kasai portoenterostomy (BA) and surgery for other liver disorders (non-BA). The non-BA organoids were co-cultured with poly I:C (40 µg/mL). The organoid morphology from both samples was compared on day 17. RNA-sequencing was performed to examine the transcriptomic differences. Results: Non-BA liver organoids developed into well-expanded spherical organoids with a single-cell layer of epithelial cells and a single vacuole inside. After poly I:C treatment, the majority of these organoids developed into an aberrant morphology with a high index of similarity to BA organoids which are multi-vacuoled and/or unexpanded. RNA-sequencing analysis revealed that 19 inflammatory genes were commonly expressed in both groups. Conditional cluster analysis revealed several genes (SOCS6, SOCS6.1, ARAF, CAMK2G, GNA1C, ITGA2, PRKACA, PTEN) that are involved in immune-mediated signaling pathway had a distinct pattern of expression in the poly I:C treated organoids. This resembled the expression pattern in BA organoids (p < 0.05). Conclusions: Poly I:C treated human liver organoids exhibit morphology and genetic signature highly compatible to organoids developed from BA liver samples. They are potential research materials to study immune-mediated inflammation in BA.

Current Understanding in the Clinical Characteristics and Molecular Mechanisms in Different Subtypes of Biliary Atresia.

Biliary atresia is a severe obliterative cholangiopathy in early infancy that is by far the most common cause of surgical jaundice and the most common indicator for liver transplantation in children. With the advanced knowledge gained from different clinical trials and the development of research models, a more precise clinical classification of BA (i.e., isolated BA (IBA), cystic BA (CBA), syndromic BA (SBA), and cytomegalovirus-associated BA (CMVBA)) is proposed. Different BA subtypes have similar yet distinguishable clinical manifestations. The clinical and etiological heterogeneity leads to dramatically different prognoses; hence, treatment needs to be specific. In this study, we reviewed the clinical characteristics of different BA subtypes and revealed the molecular mechanisms of their developmental contributors. We aimed to highlight the differences among these various subtypes of BA which ultimately contribute to the development of a specific management protocol for each subtype.

Human liver organoid derived intra-hepatic bile duct cells support SARS-CoV-2 infection and replication.

Although the main route of infection for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the respiratory tract, liver injury is also commonly seen in many patients, as evidenced by deranged parenchymal liver enzymes. Furthermore, the severity of liver damage has been shown to correlate with higher mortality. Overall, the mechanism behind the liver injury remains unclear. We showed in this study that intra-hepatic bile duct cells could be grown using a human liver organoid platform. The cholangiocytes were not only susceptible to SARS-CoV-2 infection, they also supported efficient viral replication. We also showed that SARS-CoV-2 replication was much higher than SARS-CoV. Our findings suggested direct cytopathic viral damage being a mechanism for SARS-CoV-2 liver injury.

Gut lumen formation defect can cause intestinal atresia: evidence from histological studies of human embryos and intestinal atresia septum.

Intestinal atresia (IA), a common cause of neonatal intestinal obstruction, is a developmental defect, which disrupts the luminal continuity of the intestine. Here, we investigated (i) the process of lumen formation in human embryos; and (ii) how a defective lumen formation led to IA. We performed histological and histochemical study on 6-10 gestation week human embryos and on IA septal regions. To investigate the topology of embryonic intestine development, we conducted 3D reconstruction. We showed that a 6-7th gestation week embryonic gut has no lumen, but filled with mesenchyme cells and vacuoles of a monolayer of epithelial cells. A narrow gut lumen was formed by gestation week-9, the gut was filled with numerous vacuoles of different sizes, some vacuoles were merging with the developing embryonic gut wall. At gestation week-10, a prominent lumen was developed, only few vacuoles were present and were merging with the intestine wall. At IA septal regions, vacuoles were located in the submucous layer, covered by a single layer of epithelium without glandular structure, and surrounded with fibrous tissue. The mucosal epithelium was developed with lamina propria and basement membrane, but the submucosa and the longitudinal smooth muscle layers were not properly developed. Hence, the vacuoles in IA septum could represent a remnant of vacuoles of embryonic gut. In conclusion, the fusion of vacuoles with the developing intestine wall associates with the disappearance of vacuoles and gut lumen formation in human embryos, and perturbation of these developmental events could lead to IA.

Biliary Atresia - emerging diagnostic and therapy opportunities.

Biliary Atresia is a devastating pediatric cholangiopathy affecting the bile ducts of the liver. In this review, we describe recent progress in the understanding of liver development with a focus on cholangiocyte differentiation and how use of technical platforms, including rodent, zebrafish and organoid models, advances our understanding of Biliary Atresia. This is followed by a description of potential pathomechanisms, such as autoimmune responses, inflammation, disturbed apical-basal cell polarity, primary cilia dysfunction as well as beta-amyloid accumulation. Finally, we describe current and emerging diagnostic opportunities and recent translation breakthroughs for Biliary Atresia in the area of emerging therapy development, including immunomodulation and organoid-based systems for liver and bile duct repair.

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.

Down-regulation of STAT3 enhanced chemokine expression and neutrophil recruitment in biliary atresia.

Biliary atresia (BA) is an immune-related disorder and signal transducer and activator of transcription 3 (STAT3) is a key signalling molecule in inflammation. The present study was designed to clarify the function of STAT3 in BA. STAT3 expression was examined in patients and a mouse BA model in which STAT3 levels were further altered with a specific inhibitor or activator. Neutrophil accumulation and the levels of the neutrophil chemoattractants (C-X-C motif) ligand 1 (CXCL1) and IL-8 were determined. The effects of STAT3 inhibition on IL-8 expression were examined in human biliary epithelial cell (BEC) cultures. Functional changes in liver STAT3+ neutrophils in the mouse model were analysed with 10× single cell RNA-seq methods. Results showed STAT3 and p-STAT3 expression was reduced in BA liver tissue compared with control samples. Administration of a STAT3 inhibitor increased jaundice and mortality and reduced body weight in BA mice. In contrast, the STAT3 activator ameliorated BA symptoms. Extensive neutrophil accumulation together with CXCL1 up-regulation, both of which were suppressed by an anti-CXCL1 antibody, were observed in the STAT3 inhibitor-treated group. Recombinant IL-8 administration increased disease severity in BA mice, and the STAT3 activator had the reverse effect. Inhibiting STAT3 increased apoptosis of human BECs together with up-regulated IL-8 expression. RNA-seq analysis revealed reduced the numbers of STAT3 expressing neutrophil in BA which was accompanied by marked enhanced interferon-related antiviral activities. In conclusion, STAT3 reduction, enhanced IL-8 and CXCL1 expression and promoted the accumulation of interferon-responsive neutrophils resulting in BEC damage in BA.