title: The origin of biliary ductular cells that appear in the spleen after transplantation of hepatocytes.
abstract: Transplantation of rat hepatocytes into the syngeneic rat spleen results in the appearance of cytokeration (CK)-19-positive biliary cells that form ductules. The exact origin of CK-19-positive cells is not known and the possibility that they are derived from biliary cells or precursors of oval cells in transplanted hepatocyte preparations has been raised. In the present study, we found that the number of CK-19-positive biliary cells increased rapidly after transplantation of hepatocytes, reached the maximum at 4 weeks, and then gradually decreased. However, a Ki-67 labeling index of CK-19-positive biliary cells was low and showed no significant changes throughout the experimental period. In addition, no or few CK-19-positive cells appeared in the spleen after transplantation of nonparenchymal liver cells enriched with biliary cells. These results showed that biliary cells were not the source of CK-19-positive cells in the spleen. Impairment of precursors of oval cells in the liver by administration of 4,4'-diaminodiphenylmethane 24 h before transplantation of hepatocytes did not prevent the appearance of CK-19-positive biliary cells in the spleen. Moreover, transplantation of nonparenchymal cells carrying an increased number of oval cells by means of treatment with 2-acetylaminofluorene and partial hepatectomy resulted in no appearance of CK-19-positive biliary cells in the spleen. These results ruled out oval cells as the origin of CK-19-positive biliary cells in the spleen. Because CK-19-positive biliary cells appeared in the spleen only when hepatocyte fractions were transplanted, we suggest transdifferentiation of heptocytes may be the mechanism by which CK-19-positive biliary cells are generated.
authors.affiliation: Department of Otolaryngology, Hyogo College of Medicine, 1-1 Mukogawa-cho, Nishinomiya, Hyogo 663-8501, Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Fukuda
authors.forename: Ayako
authors.initials: A
authors.lastname: Sugihara
authors.forename: Keiji
authors.initials: K
authors.lastname: Nakasho
authors.forename: Tohru
authors.initials: T
authors.lastname: Tsujimura
authors.forename: Naoko
authors.initials: N
authors.lastname: Yamada
authors.forename: Atsuhito
authors.initials: A
authors.lastname: Okaya
authors.forename: Masafumi
authors.initials: M
authors.lastname: Sakagami
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Terada
mesh_terms: D000818:Animals; D001652:Bile Ducts / Q000166:cytology* / Q000473:pathology; D002469:Cell Separation / Q000379:methods; D017690:Cell Transplantation / Q000379:methods*; D006498:Hepatectomy; D022781:Hepatocytes / Q000166:cytology* / Q000187:drug effects / Q000637:transplantation*; D006965:Hyperplasia; D019394:Ki-67 Antigen / Q000032:analysis; D008099:Liver / Q000166:cytology / Q000187:drug effects; D008297:Male; D010649:Phenylalanine / Q000031:analogs & derivatives* / Q000494:pharmacology; D051381:Rats; D011916:Rats, Inbred F344; D013154:Spleen / Q000166:cytology*
chemical_list: D019394:Ki-67 Antigen; C005628:DAPM; D010649:Phenylalanine