EXPRESSION OF PANCREATIC-ENZYMES (ALPHA-AMYLASE, TRYPSINOGEN, AND LIPASE) DURING HUMAN LIVER DEVELOPMENT AND MATURATION

Background/Aims: Although pancreatic enzymes have been found in hilar intrahepatic bile ducts in adult humans, their expression during human liver development is unclear. The aim of this study was to clarify the temporal expression of pancreatic enzymes at various stages of human liver development. Methods: We immunohistochemically investigated pancreatic alpha-amylase, trypsinogen, and lipase expression in fetal, neonatal, juvenile, and adult human livers. Results: In hilar duct development, alpha-amylase but not trypsinogen or lipase was expressed in the ductal plate. These three enzymes were expressed in, biliary cells migrating into the mesenchyma, in immature ducts in fetal livers, and in maturing and mature ducts in postnatal livers. Their expression was weak and diffusely cytoplasmic in fetal livers, whereas in postnatal livers their expression was strong, granular, and located in the supranuclear cytoplasm. Expression was not found in developing peripheral ducts. These enzymes were expressed in immature hepatocytes (9-25 weeks' gestation) but disappeared thereafter. Enzyme expression was mild in fetal pancreata and strong in adult pancreata. Conclusions: Pancreatic enzymes may be present in primitive hilar bile ducts and hepatocytes in fetal livers; hilar ducts, hepatocytes, and pancreas may have similar fetal enzymatic profiles. Intrahepatic hilar bile ducts, hepatocytes, and exocrine pancreas may have a common cell lineage.