In a recent article published in Gastroenterology, Carpentier et al.1 suggested that embryonic ductal plate cells give rise to cholangiocytes, periportal hepatocytes, and adult liver progenitor cells. Herein, the authors demonstrated that the ductal plate also gives rise to pancreatic acinar cells and intrahepatic peribiliary glands.2 The authors previously reported that clusters of pancreatic acinar cells are present in normal adult livers.3 The ductal plate is a double-layered cylindrical structure located in the periportal regions of the fetal liver (Fig. 1A).4-8 The ductal plate undergoes remodeling (Fig. 1B,C), leading to the normal cholangiocytes and intrahepatic peribiliary glands.4-8 The remodeling involves apoptosis and cell proliferation of the ductal plate. Several molecules, such as glycoconjugates, Levis y, Bcl-2, C-myc, tenascin, matrix metalloproteinases, tissue inhibitors of matrix metalloproteinases, trypsin, pancreatic digestive enzymes, E-cadherin, and catenin, are involved in the process of ductal plate remodeling.2-10 Pancreatic acinar cell clusters develop from the remodeling ductal plate.4, 8 The authors again reviewed 42 fetal livers of various gestational ages and 32 postnatal livers, and observed that intrahepatic peribiliary glands developed from the remodeling ductal plate at 35 to 40 gestational weeks for fetal livers as well as in the infant livers. The authors also found that pancreatic acinar cells developed from remodeling and remodeled ductal plate at 38 to 40 gestational weeks for fetal livers (Fig. 1D) as well as infant livers of 1 to 3 months (Fig. 1E). Immunohistochemically, the pancreatic acinar cells contained pancreatic amylase, trypsinogen, and lipase.
To the Editor:
Tadashi Terada M.D., Ph.D.*, * Department of Pathology, Shizuoka City Shimizu Hospital, Shizuoka, Japan.