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Human ontogeny of the bile duct to portal space ratio
1Department of Laboratories, North Shore University Hospital-Cornell University Medical College, Manhasset, New York 11030.
Insights
In premature infants, a low bile duct to portal space ratio may be normal before 38 weeks postconception. This finding is crucial for diagnosing cholestatic liver disease in neonates.
Area of Science:
- Pediatric Hepatology
- Neonatal Pathology
- Developmental Biology
Background:
- Paucity of interlobular bile ducts is characteristic of cholestatic liver disease in premature infants.
- Established normal bile duct to portal space ratios exist for children but not for preterm infants.
- Accurate diagnostic criteria for neonatal cholestasis are essential for timely intervention.
Purpose of the Study:
- To establish the normal range for the bile duct to portal space ratio in preterm infants.
- To determine the relationship between postconceptional age and bile duct to portal space ratio.
- To provide guidelines for the interpretation of liver biopsies in evaluating duct paucity in neonates.
Main Methods:
- Histological examination of liver tissue from autopsied fetuses and infants.
- Quantification of the bile duct to portal space ratio.
- Correlation of the ratio with postconceptional age.
Main Results:
- The bile duct to portal space ratio increases with postconceptional age.
- A ratio of 0.9 or greater was observed in 89% of subjects after 38 weeks postconception.
- A ratio below 0.9 may be physiologically normal before 38 weeks postconception.
Conclusions:
- Liver biopsies for evaluating bile duct paucity in premature infants should be performed after 38 weeks postconception.
- A bile duct to portal space ratio below 0.9 is likely physiologic in infants younger than 38 weeks.
- These findings aid in the accurate diagnosis of neonatal cholestatic liver disease.
Abstract:
Paucity of interlobular bile ducts is a common feature of cholestatic liver disease in premature infants. Whereas a bile duct to portal space ratio of 0.9 to 1.8 is cited by Alagille as the norm for children, there are no data regarding the normal bile duct to portal space ratio in preterm infants. In this study, by examining liver tissue obtained from autopsied fetuses and infants, we have determined that the bile duct to portal space ratio increases as a function of postconceptional age. After 38 weeks postconception, a ratio equal to or greater than 0.9 was seen in eight of nine subjects. Therefore, in evaluating premature infants for duct paucity, liver biopsies should be obtained only after 38 weeks. Prior to 38 weeks postconception, a bile duct to portal space ratio less than 0.9 may be physiologic.