Long-Term, Near-Total Liver Replacement by Transplantation of Isolated Hepatocytes in Rats Treated with Retrorsine

Abstract

Genetically marked hepatocytes from dipeptidyl peptidase (DPP) IV؉ Fischer 344 rats were transplanted into the liver of DPPIV ؊ mutant Fischer 344 rats after a combined treatment with retrorsine , a pyrrolizidine alkaloid that blocks the hepatocyte cell cycle, and two-thirds partial hepatectomy. In female rats , clusters of proliferated DPPIV ؉ hepatocytes containing 20 to 50 cells/cluster , mostly derived from single transplanted cells , were evident at 2 weeks , increasing in size to hundreds of cells per cluster at 1 month and 1000 to several thousand cells per cluster at 2 months, representing 40 to 60% of total hepatocyte mass. This level of hepatocyte replacement remained constant for up to 1 year , the duration of experiments conducted. In male rats , liver replacement occurred more rapidly and was more extensive , with transplanted hepatocytes representing 10 to 15% of hepatocyte mass at 2 weeks , 40 to 50% at 1 month , 90 to 95% at 2 months , 98% at 4 months , and 99% at 9 months.

Stem cells in liver regeneration, fibrosis and cancer: the good, the bad and the ugly

“…Important from a human standpoint, such cells can be cryopreserved for up to 20 months with no loss of repopulating activity [50]. Many studies have also examined the transplantation potential of adult hepatocytes in the DPPIV − mutant rat, combining retrorsine treatment with a mitogenic stimulus, such as partial hepatectomy or triidothyronine (T3), leading to the rapid replacement of DPPIV − cells by DPPIV + donor cells [51,52]; even in the absence of a mitogenic stimulus, near-total replacement by donor cells occurs within 12 months [53].…”

Comparison of hepatic properties and transplantation of Thy-1+and Thy-1−cells isolated from embryonic day 14 rat fetal liver

“…In contrast to Thy-1 Ϫ fetal liver cells, Thy-1 ϩ fetal liver cells are unable to repopulate the normal host liver, but they can repopulate retrorsine-treated rat liver, an animal model in which host hepatocyte proliferation is markedly impaired. 5 These findings suggest that Thy-1 ϩ fetal liver cells at ED14 represent a population of progenitor cells that can repopulate only a massively injured liver, whereas Thy-1 Ϫ fetal liver cells are stem/progenitor cells that exhibit greater proliferation potential and can repopulate the normal adult liver.…”

“…2 Several animal models have been established in which transplanted hepatocytes effectively replace the recipient liver, but this requires both extensive and continuous liver injury and significant selection pressure favoring the proliferation/ survival of transplanted cells. [3][4][5][6][7][8][9] However, opportunities to transplant hepatocytes under these circumstances will be encountered infrequently in clinical medicine. Therefore, there is substantial interest in identifying candidate stem or progenitor cells for liver cell transplantation.…”

Liver gene therapy: advances and hurdles

“…8 Accordingly, when host hepatocytes were prevented from proliferating, small clusters of proliferating donor hepatocytes could be detected by day 4 posthepatectomy. 85 In addition, overexpression of urokinase or the cell cycle regulator Mad1 by host hepatocytes using adenovirus-mediated gene transfer before cell transplantation triggered hepatocyte death and slow liver regeneration, allowing expansion of transplanted hepatocyte mass. Hepatocyte engraftment could also be significantly increased: (i) by increasing the number of donor cells depositing in hepatic sinusoids using vasodilators; (ii) by disrupting the sinusoidal endothelial endothelium using drugs such as cyclosphamide; and (iii) by depleting macrophage/Kuppfer cells prior to hepatocyte transplantation using gadolinium chloride.…”

“…[1][2][3]67,88 To apply this principle to most liver disorders, in which host diseased hepatocytes could compete with donor hepatocytes for liver repopulation, animals were pretreated with retrorsine or subjected to whole liver irradiation to inhibit proliferation ability of host hepatocytes before cell transplantation. 85,89,90 In combination with a strong regenerative pressure (eg twothirds partial hepatectomy, thyroid hormone administration, ischemia-reperfusion injury or FasL gene transfer), a nearly complete repopulation of host liver by donor hepatocytes was obtained after transplantation of 0.5% of the recipient liver mass. 89,[91][92][93] Similarly, lentivirally transduced hepatocytes were massively expanded in retrorsine/partial hepatectomy-treated rats.…”