Correction of Liver Disease Following Transplantation of Normal Rat Hepatocytes into Long–Evans Cinnamon Rats Modeling Wilson's Disease

Abstract

To establish the efficacy of cell therapy in Wilson's disease, we used the Long-Evans Cinnamon (LEC) rat model with atp7b gene mutation and copper toxicosis. Several groups of LEC rats were established, including animals pretreated with retrorsine to exacerbate copper toxicosis and inhibit proliferation in native hepatocytes followed by partial hepatectomy to promote liver repopulation. Hepatocytes from normal, syngeneic LEA rats were transplanted intrasplenically. Animal survival, biliary copper excretion, and hepatic copper were determined. The magnitude of liver repopulation was demonstrated by measuring serum ceruloplasmin and hepatic atp7b mRNA. Long-term survival in LEC rats treated with retrorsine, partial hepatectomy, and cell transplantation was up to 90%, whereas fewer than 10% of animals pretreated with retrorsine, without cell therapy, survived, P < 0.001. Liver repopulation occurred gradually after cell transplantation, ranging from <25% at 6 weeks, 26 to 40% at 4 months, and 74 to 100% at 6 months or beyond. Liver repopulation restored biliary copper excretion capacity and lowered liver copper levels. Remarkably, liver histology was completely normal in LEC rats with extensive liver repopulation, compared with widespread megalocytosis, apoptosis, oval cell proliferation, and cholangiofibrosis in untreated animals. These data indicate that liver repopulation with functionally intact cells can reverse pathophysiological perturbations and cure Wilson's disease.

Cell transplantation after oxidative hepatic preconditioning with radiation and ischemia–reperfusion leads to extensive liver repopulation

“…On the other hand, if transplanted cells would possess selective proliferation advantages, as shown here, far superior results could be achieved. In animals with chronic liver disease, loss of diseased native hepatocytes promotes survival and proliferation of healthy transplanted cells (8)(9)(10)(11)28). In some situations, as shown by studies in LEC rats and Pgy-2-knockout mice, proliferation of transplanted cells requires several months (12,28), whereas the use of preconditioning regimens enormously accelerates liver repopulation with obvious improvements in cell therapy results.…”

Cyclophosphamide disrupts hepatic sinusoidal endothelium and improves transplanted cell engraftment in rat liver

“…[5][6][7][8][9][10] The possibility of therapeutic liver repopulation has been tested in several animal models with liver failure, genetic diseases, and metabolic deficiency states. [11][12][13][14] The swiftness with which transplanted cells engraft could be critical for liver repopulation. After injection into the portal system, transplanted cells lodge in hepatic sinusoids because of differences in the dimensions of these cells and sinusoids.…”

“…19 Additional evidence indicates that toxins may interfere with transplanted cell engraftment, e.g., in mice expressing herpes simplex virus thymidine kinase transgene, which activates ganciclovir, with hepatotoxicity, 10 or after copper accumulation in rats with severe liver disease. 13 In these situations, lobule-to-lobule variability in transplanted cell proliferation or delayed transplanted cell proliferation with lower magnitudes of liver repopulation has been observed. Therefore, if delayed integration of transplanted cells in the liver accounts for impaired proliferation of transplanted hepatocytes, one could reason that accelerated cell engraftment should benefit liver repopulation.…”

Liver Injury Models for Induction of Hepatic Oval Cells in Rodents

“…Mutation of the Atp7b gene creates Long-Evans Cinnamon rats that have toxic accumulation of copper within the liver. Spontaneous hepatitis develops at 16 weeks of age with concomitant oval cell proliferation [170,171]. Homozygous obese (ob/ob) mice develop steatohepatitis and oval cell responses similar to alcohol-induced models [7,45].…”