retrorsine and Liver-Failure--Acute

Efficient repopulation by transplanted hepatocytes in the severely injured liver is essential for their clinical application in the treatment of acute hepatic failure. We studied here whether and how the transplanted hepatocytes are able to efficiently repopulate the toxin-induced acute injured liver. Male dipeptidyl peptidase IV-deficient F344 rats were randomized to receive retrorsine plus D-galactosamine (R+D-gal) treatment or D-galactosamine-alone (D-gal) to induce acute hepatic injury, and retrorsine-alone. In these models, retrorsine was used to inhibit the proliferation of endogenous hepatocytes while D-galactosamine induced acute hepatocyte damage. Wild-type hepatocytes (1 x 10(7)/ml) were transplanted intraportally 24 h after D-galactosamine or saline injection. The kinetics of proliferation and repopulation of transplanted cells and the kinetics of cytokine response, hepatic stellate cell (HSC) activation, and matrix metalloproteinase (MMP2) expression were analyzed. We observed that early entry of transplanted hepatocytes into the hepatic plates and massive repopulation of the liver by transplanted hepatocytes occurred in acute hepatic injury induced by R+D-gal treatment but not by D-gal-alone or retrorsine-alone. The expressions of transforming growth factor-alpha and hepatocyte growth factor genes in the R+D-gal injured liver were significantly upregulated and prolonged up to 4 weeks after hepatocyte transplantation. The expression kinetics were parallel with the efficient proliferation and repopulation of transplanted hepatocytes. HSC was activated rapidly, markedly, and prolongedly up to 4 weeks after hepatocyte transplantation, when the expression of HGF gene and repopulation of transplanted hepatocytes were reduced afterward. Furthermore, the expression kinetics of MMP2 and its specific distribution in the host areas surrounding the expanding clusters of transplanted hepatocytes are consistent with those of activated HSC. Impaired hepatocyte regeneration after acute severe hepatic injury may initiate serial compensatory repair mechanisms that facilitate the extensive repopulation by transplanted hepatocytes that enter early the hepatic plates.

Topics: Animals; Chemical and Drug Induced Liver Injury; Galactosamine; Hepatic Stellate Cells; Hepatocyte Growth Factor; Hepatocytes; Liver Failure, Acute; Liver Regeneration; Male; Matrix Metalloproteinase 2; Pyrrolizidine Alkaloids; Rats; Rats, Inbred F344; Transforming Growth Factor alpha; Up-Regulation

Hepatocyte transplantation is effective for treating liver failure, but healthy donors as a source of hepatocytes are quite limited. The livers of patients with hepatic fibrosis could be an alternative source; however, few reports have examined the nature of hepatocytes from fibrotic livers (f-hepatocytes). In this study, we compared the growth of f-hepatocytes and hepatocytes from normal livers (n-hepatocytes). Hepatocytes were isolated from normal and CCl(4)-treated wild-type Fischer rats that express dipeptidyl dipeptidase IV (DPPIV) gene (DPPIV(+)). The n- and f-hepatocytes proliferated in culture at similar rates. Both types of hepatocytes were transplanted into DPPIV(-) mutant Fischer rats that had been treated with retrorsine to injure the liver and were partially hepatectomized (PHx) before transplantation. Both n- and f-DPPIV(+)-hepatocytes proliferated and formed colonies. The colony sizes of f-hepatocytes 21 days posttransplantation were approximately three times those of n-hepatocytes. The hepatocytes were analyzed using a fluorescence activated cell sorter (FACS). The FACS profile differed between f- and n-hepatocytes: f-hepatocytes were less granular, less autofluorescent, and smaller than n-hepatocytes. These characteristics of f-hepatocytes resembled those reported for small-sized n-hepatocytes (SHs), which are highly proliferative and preferentially express a unique set of 10 SH genes. However, f-hepatocytes preferentially expressed only five of the SH genes. The expression profile of f-hepatocytes was rather similar to that of proliferating n-hepatocytes in the regenerating liver after PHx. The f-hepatocytes were morphologically normal and did not show any preneoplastic phenotype. These normal and proliferative natures of f-hepatocytes in vivo suggest the fibrotic liver as a source of hepatocytes for transplantation.

Topics: Animals; Antineoplastic Agents, Phytogenic; Cell Proliferation; Cell Transplantation; Dipeptidyl Peptidase 4; Flow Cytometry; Hepatectomy; Hepatocytes; Liver; Liver Cirrhosis; Liver Failure, Acute; Male; Pyrrolizidine Alkaloids; Rats

Adult bone marrow contains progenitors capable of generating hepatocytes. Here a new liver failure model is introduced to assess whether bone marrow-derived progeny contribute to liver regeneration after acute hepatotoxic liver failure.. Retrorsine was used to inhibit endogenous hepatocyte proliferation, before inducing acute liver failure by carbon tetrachloride. Bone marrow chimeras were generated before inducing liver failure to trace bone marrow-derived cells. Therefore, CD45 and major histocompatibility complex (MHC) class I dimorphic rat models were applied.. Early after acute liver failure a multilineage inflammatory infiltrate was observed, mainly consisting of granulocytes. In long-term experiments small numbers of CD90+/CD45- cells of donor origin occurred in clusters associated with portal triads. Bone marrow cell infusion was not able to enhance liver regeneration. Cellular hypertrophy was the predominant way of liver mass regeneration in models applying retrorsine.. Retrorsine pretreatment did not affect sensitivity for carbon tetrachloride. A multilineage inflammatory infiltrate was observed in rats whether pretreated with retrorsine or not. Few donor cells co-expressing CD90 (THY 1) were present in recipient livers, which may resemble donor-derived hematopoietic progenitors or oval cells. No other donor cells within liver parenchyma were detected. This is in contrast to other cell infusion models of acute cell death.

Topics: Animals; Bone Marrow Cells; Bone Marrow Transplantation; Carbon Tetrachloride; Cell Line; Chimera; Disease Models, Animal; Granulocytes; Hematopoietic Stem Cells; Leukocyte Common Antigens; Liver; Liver Failure, Acute; Liver Regeneration; Pyrrolizidine Alkaloids; Rats; Rats, Inbred Lew; Thy-1 Antigens