Distribution of apoptotic cells and expression of apoptosis-related proteins along the intrahepatic biliary tree in normal and non-biliary diseased liver.
OBJECTIVE
The cell kinetics and homeostasis of biliary epithelial cells may be maintained differently along the biliary tree. In this study, the role of apoptosis in the maintenance and homeostasis of the intrahepatic biliary tree was evaluated.


RESULTS
By counting apoptotic biliary cells and by immunostaining apoptosis-related proteins in normal liver, fatty liver, and those with acute viral hepatitis, chronic viral hepatitis, and hepatitis virus-related cirrhosis, it was found that the larger the intrahepatic bile ducts became, the more biliary epithelial cells underwent apoptosis. bcl-2, an inhibitor of apoptosis, was diffusely expressed in the interlobular bile ducts, but rarely detectable in the large and septal bile ducts. bcl-XL and mcl-1, inhibitors of apoptosis, and bax, a promoter of apoptosis, were diffusely expressed along the intrahepatic biliary tree. CD95, a direct inducer of apoptosis, was present in the large and septal bile ducts, but rarely in the interlobular bile ducts.


CONCLUSIONS
The ratio of bax to bcl-2, as well as the expression of CD95 which differed at the interlobular versus large and septal bile ducts, may be responsible for the unique distribution of apoptotic biliary cells and involved in the homeostasis of the intrahepatic biliary tree.
Harada
K
K
Second Department of Pathology, Kanazawa University School of Medicine, Kanazawa, Japan.
Iwata
M
M
Kono
N
N
Koda
W
W
Shimonishi
T
T
Nakanuma
Y
Y
D000368:Aged; D017209:Apoptosis; D001653:Bile Ducts, Intrahepatic / Q000737:chemistry / Q000473:pathology*; D015153:Blotting, Western; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008099:Liver / Q000737:chemistry* / Q000473:pathology; D008107:Liver Diseases / Q000378:metabolism / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D064549:Myeloid Cell Leukemia Sequence 1 Protein; D009363:Neoplasm Proteins / Q000032:analysis; D011518:Proto-Oncogene Proteins / Q000032:analysis; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000032:analysis; D051028:bcl-2-Associated X Protein; D051020:bcl-X Protein; D019014:fas Receptor / Q000032:analysis
C494826:BAX protein, human; C494811:BCL2L1 protein, human; D064549:Myeloid Cell Leukemia Sequence 1 Protein; D009363:Neoplasm Proteins; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D051028:bcl-2-Associated X Protein; D051020:bcl-X Protein; D019014:fas Receptor