Liver repopulation and carcinogenesis: two sides of the same coin?

Liver repopulation by transplanted normal hepatocytes has been described in a number of experimental settings. Extensive repopulation can also occur from the selective proliferation of endogenous normal hepatocytes, both in experimental animals and in the human liver. This review highlights the intriguing association between clinical and experimental conditions related to liver repopulation and an increased risk for development of hepatocellular carcinoma.

Repopulation by endogenous hepatocytes does not reconstitute liver mass in rats treated with retrorsine.

The retrorsine (RS)-based model for massive liver repopulation was laid on the hypothesis that transplanted cells can proliferate in the recipient liver if the growth capacity of endogenous hepatocytes is persistently impaired. In order to directly test this hypothesis, we examined the long-term response to 2/3 partial hepatectomy (PH) in rats pretreated with RS, according to the protocol for liver repopulation. Rats were given RS or saline and 4 weeks later they underwent PH; they were killed up to 16 weeks thereafter.

Liver repopulation by transplanted hepatocytes and risk of hepatocellular carcinoma.

Background: Transplantation of isolated hepatocytes in rats treated with retrorsine (RS) results in massive repopulation of the host liver. In this study, the long-term fate of hepatocytes transplanted into RS-treated recipients was followed for up to two years.

Methods: Dipeptidyl-peptidase type IV-deficient (DPPIV) Fischer 344 rats were given two injections of RS (30 mg/kg), followed by transplantation of 2 million hepatocytes, isolated from a syngenic, DPPIV donor.

Aging is associated with increased clonogenic potential in rat liver in vivo.

Cancer increases with age and often arises from the selective clonal growth of altered cells. Thus, any environment favoring clonal growth per se poses a higher risk for cancer development. Using a genetically tagged animal model, we investigated whether aging is associated with increased clonogenic potential.

Cyclin D1 is up-regulated in hepatocytes in vivo following cell-cycle block induced by retrorsine.

Background/aims: We reported massive liver repopulation by transplanted hepatocytes in rats given retrorsine (RS), a pyrrolizidine alkaloid which blocks proliferation of resident cells. In these studies, molecular alterations induced by RS on hepatocyte cell cycle were investigated.

Methods: Animals were treated according to the protocol for liver repopulation, i.