Significance and therapeutic potential of endothelial progenitor cell transplantation in a cirrhotic liver rat model.
OBJECTIVE
We investigated whether endothelial progenitor cell (EPC) transplantation could reduce established liver fibrosis and promote hepatic regeneration by isolating rat EPCs from bone marrow cells.


METHODS
Recipient rats were injected intraperitoneally with carbon tetrachloride (CCl(4)) twice weekly for 6 weeks before initial administration of EPCs. CCl(4) was then readministered twice weekly for 4 more weeks, and EPC transplantation was carried out for these same 4 weeks.


RESULTS
At 7 days in culture, the cells expressed Thy-1, CD31, CD133, Flt-1, Flk-1, and Tie-2, suggesting an immature endothelial lineage. Immunohistochemical analyses showed fluorescent-labeled, transplantation EPCs were incorporated into the portal tracts and fibrous septa. Single and multiple EPC transplantation rats had reduced liver fibrosis, with decreased alpha2-(I)-procollagen, fibronectin, transforming growth factor-beta, and alpha-smooth muscle actin-positive cells. Film in situ zymographic analysis revealed strong gelatinolytic activity in the periportal area, in accordance with EPC location. Real-time polymerase chain reaction analysis of multiple EPC-transplantation livers showed significantly increased messenger RNA levels of matrix metalloproteinase (MMP)-2, -9 and -13, whereas tissue inhibitor of metalloproteinase-1 expression was significantly reduced. Expression of hepatocyte growth factor, transforming growth factor-alpha, epidermal growth factor, and vascular endothelial growth factor was increased in multiple EPC-transplantation livers, while hepatocyte proliferation increased. Transaminase, total bilirubin, total protein, and albumin levels were maintained in EPC-transplantation rats, significantly improving survival rates.


CONCLUSIONS
We conclude that single or repeated EPC transplantation halts established liver fibrosis in rats by suppressing activated hepatic stellate cells, increasing matrix metalloproteinase activity, and regulating hepatocyte proliferation.
Nakamura
Toru
T
Division of Gastroenterology, Department of Medicine, Kurume University School of Medicine, Kurume, Fukuoka, Japan. ntoru@med.kurume-u.ac.jp <ntoru@med.kurume-u.ac.jp>
Torimura
Takuji
T
Sakamoto
Masaharu
M
Hashimoto
Osamu
O
Taniguchi
Eitaro
E
Inoue
Kinya
K
Sakata
Ryuichiro
R
Kumashiro
Ryukichi
R
Murohara
Toyoaki
T
Ueno
Takato
T
Sata
Michio
M
D000818:Animals; D001854:Bone Marrow Cells / Q000166:cytology; D002251:Carbon Tetrachloride; D002455:Cell Division; D002478:Cells, Cultured; D004195:Disease Models, Animal; D042783:Endothelial Cells / Q000166:cytology; D006085:Graft Survival; D022781:Hepatocytes / Q000166:cytology / Q000201:enzymology; D017404:In Situ Hybridization, Fluorescence; D008103:Liver Cirrhosis / Q000139:chemically induced / Q000473:pathology / Q000628:therapy*; D008115:Liver Regeneration; D008297:Male; D020782:Matrix Metalloproteinases / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D033581:Stem Cell Transplantation / Q000379:methods*; D013853:Thioacetamide; D019715:Tissue Inhibitor of Metalloproteinase-1 / Q000235:genetics / Q000378:metabolism; D015854:Up-Regulation
D012333:RNA, Messenger; D019715:Tissue Inhibitor of Metalloproteinase-1; D013853:Thioacetamide; D002251:Carbon Tetrachloride; D020782:Matrix Metalloproteinases