title: Human fetal ductal plate revisited. I. ductal plate expresses NCAM, KIT, MET, PDGFRA, and neuroendocrine antigens (NSE, chromogranin, synaptophysin, and CD56).
abstract: BACKGROUND
  The molecular mechanisms of ductal plate (DP) development and differentiation (DD) in human fetal livers (HFLs) are unclear.
  
  
  METHODS
  The author immunohistochemically investigated expressions of NCAM, KIT, KIT, PDGFRA, and neuroendocrine antigens in 32 HFLs.
  
  
  RESULTS
  The processes of human intrahepatic bile duct (IBD) DD could be categorized into four stages: DP, remodeling DP, remodeled DP, and mature IBD. NCAM was always expressed in DP and remodeling DP, but not in remodeled DP and mature IBD. The biliary elements were positive for cytokeratin (CK)7, 8, 18, and 19. The hepatoblasts were positive for CK8 and CD18, but negative for CK7 and CK19; however, periportal hepatoblasts showed biliary-type CKs (CK7 and CK19). NCAM was always expressed in DP and remodeling DP, but not in remodeled DP and mature IBD. KIT was occasionally (12/32 cases) expressed in DP and remodeling DP, but not in remodeled DP and mature IBD. NCAM expression was also seen in some hepatoblasts and hematopoietic cells and neurons. KIT was also expressed in some hepatoblasts, hematopoietic cells, and mast cells. MET and PDGFRA were strongly expressed in DP, remodeling DP, remodeled DP, and mature IBD. MET and PDGFRA were also strongly expressed in hepatoblasts and hematopoietic cells. MET and PDGFRA were not expressed in portal mesenchyme, portal veins, sinusoids, and hepatic veins. DP showed immunoreactive chromogranin, synaptophysin, neuron-specific enolase (NSE), and CD56. Expressions of chromogranin and CD56 were infrequently seen in remodeling DP. No expressions of these four neuroendocrine antigens were seen in remodeled DP and mature IBD. The nerve fibers were consistently positive for chromogranin, synaptophysin, NSE, and CD56 in the portal mesenchyme in the stages of remodeling DP, remodeled DP, and mature IBDs.
  
  
  CONCLUSIONS
  The data suggest that NCAM, KIT/stem cell factor-signaling, NSE, hepatocyte growth factor/MET signaling, PDGFα/PDGFRA signaling, chromogranin, synaptophysin, and CD56 play important roles in DD of biliary cells of HFL. They also suggest that the DP cells having neuroendocrine molecules give rise to hepatic stem/progenitor cells.
authors.affiliation: Department of Pathology, Shizuoka City Shimizu Hospital, Shizuoka 424-8636, Japan.
authors.forename: Tadashi
authors.initials: T
authors.lastname: Terada
mesh_terms: D001653:Bile Ducts, Intrahepatic / Q000196:embryology* / Q000378:metabolism; D019002:CD56 Antigen / Q000378:metabolism*; D002864:Chromogranins / Q000378:metabolism*; D005333:Fetus / Q000378:metabolism* / Q000648:ultrastructure; D006801:Humans; D019006:Neural Cell Adhesion Molecules / Q000378:metabolism*; D009490:Neurosecretory Systems / Q000196:embryology / Q000378:metabolism; D019859:Proto-Oncogene Proteins c-met / Q000378:metabolism*; D020796:Receptor, Platelet-Derived Growth Factor alpha / Q000378:metabolism*; D019089:Stem Cell Factor / Q000378:metabolism*; D016708:Synaptophysin / Q000378:metabolism*
chemical_list: D019002:CD56 Antigen; D002864:Chromogranins; C522918:NCAM1 protein, human; D019006:Neural Cell Adhesion Molecules; C569014:SYP protein, human; D019089:Stem Cell Factor; D016708:Synaptophysin; C491743:MET protein, human; D019859:Proto-Oncogene Proteins c-met; D020796:Receptor, Platelet-Derived Growth Factor alpha
keywords: development; differentiation; ductal plate; embryo; fetus; human