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Updated: Jul 18, 2025
Extrahepatic Bile Duct and Gall Bladder Dissection in Nine-Day-Old Mouse Neonates
Published on: August 23, 2022
A fetal wound healing program after intrauterine bile duct injury may contribute to biliary atresia
Iris E M de Jong1, Mallory L Hunt2, Dongning Chen3
1Section of Hepatobiliary Surgery and Liver Transplantation, Department of Surgery, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands; Department of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
Insights
Biliary atresia (BA) involves fetal extrahepatic bile duct (EHBD) injury, characterized by prolonged fetal wound healing responses. Increased hyaluronic acid (HA) in EHBDs may cause obstruction and elevated bilirubin levels in neonates with BA.
Area of Science:
- Neonatal pathology
- Developmental biology
- Gastroenterology
Background:
- Biliary atresia (BA) is a neonatal obstructive cholangiopathy with uncertain etiology, often linked to prenatal factors.
- Fetal tissues exhibit elevated hyaluronic acid (HA), crucial for fetal wound healing.
- The role of fetal wound healing mechanisms in response to extrahepatic bile duct (EHBD) injury in BA is largely unknown.
Purpose of the Study:
- To investigate whether a fetal wound healing program contributes to the response to fetal EHBD injury.
- To explore the role of hyaluronic acid (HA) in the pathogenesis of biliary atresia.
Main Methods:
- Analysis of EHBD samples from mice, rats, sheep, and humans across different developmental stages.
- Utilized a fetal sheep model of prenatal hypoxia and studied human BA EHBD remnants.
- Employed in vitro models including cholangiocyte spheroids and a bile duct-on-a-chip device.
Main Results:
- Normal perinatal EHBDs exhibit a high molecular weight HA layer, absent in adults.
- Injured ducts showed expanded HA layers, peribiliary gland hyperplasia, increased mucus, and elevated bilirubin.
- BA EHBD remnants displayed increased HA around ductular structures.
- High molecular weight HA promoted cholangiocyte growth, while low molecular weight HA caused abnormal morphology and matrix swelling.
Conclusions:
- The fetal/neonatal EHBD displays a prolonged HA-rich, fetal wound healing response to injury, evident even in human BA remnants.
- Expanded peri-luminal HA may contribute to EHBD obstruction and elevated bilirubin levels in biliary atresia.
- This study offers new insights into BA pathogenesis and potential therapeutic targets.
Background & Aims:
Biliary atresia (BA) is an obstructive cholangiopathy that initially affects the extrahepatic bile ducts (EHBDs) of neonates. The etiology is uncertain, but evidence points to a prenatal cause. Fetal tissues have increased levels of hyaluronic acid (HA), which plays an integral role in fetal wound healing. The objective of this study was to determine whether a program of fetal wound healing is part of the response to fetal EHBD injury.
Methods:
Mouse, rat, sheep, and human EHBD samples were studied at different developmental time points. Models included a fetal sheep model of prenatal hypoxia, human BA EHBD remnants and liver samples taken at the time of the Kasai procedure, EHBDs isolated from neonatal rats and mice, and spheroids and other models generated from primary neonatal mouse cholangiocytes.
Results:
A wide layer of high molecular weight HA encircling the lumen was characteristic of the normal perinatal but not adult EHBD. This layer, which was surrounded by collagen, expanded in injured ducts in parallel with extensive peribiliary gland hyperplasia, increased mucus production and elevated serum bilirubin levels. BA EHBD remnants similarly showed increased HA centered around ductular structures compared with age-appropriate controls. High molecular weight HA typical of the fetal/neonatal ducts caused increased cholangiocyte spheroid growth, whereas low molecular weight HA induced abnormal epithelial morphology; low molecular weight HA caused matrix swelling in a bile duct-on-a-chip device.
Conclusion:
The fetal/neonatal EHBD, including in human EHBD remnants from Kasai surgeries, demonstrated an injury response with prolonged high levels of HA typical of fetal wound healing. The expanded peri-luminal HA layer may swell and lead to elevated bilirubin levels and obstruction of the EHBD.
Impact And Implications:
Biliary atresia is a pediatric cholangiopathy associated with high morbidity and mortality rates; although multiple etiologies have been proposed, the fetal response to bile duct damage is largely unknown. This study explores the fetal pathogenesis after extrahepatic bile duct damage, thereby opening a completely new avenue to study therapeutic targets in the context of biliary atresia.
