Restoration of serum albumin levels in nagase analbuminemic rats by hepatocyte transplantation

Recently, we described a new strategy for hepatocyte transplantation, using retrorsine/partial hepatectomy (PH) in a DPPIV- mutant Fischer rat model. Treatment of rats with retrorsine, a pyrrolizidine alkaloid, blocks endogen ous hepatocytes from proliferating, so that after exposure to this agent co upled with PH and hepatocyte transplantation, transplanted hepatocytes sele ctively repopulate the liver. In the present study, we determined whether t his method of cell transplantation can restore biosynthetic and physiologic al function in the liver by transplanting normal hepatocytes into rats gene tically deficient in albumin synthesis, the Nagase analbuminic rat (NAR). A fter hepatocyte transplantation, albumin mRNA and protein were identified i n the liver by in situ hybridization and immunohistochemistry, respectively and serum albumin levels were determined using sodium dodecyl sulfate-poly acrylamide gel electrophoresis (SDS-PAGE), Western blot, and enzyme-linked immunosorbent assay (ELISA) methods. At 1 month posttransplantation, large clusters of cells expressing albumin mRNA and protein were identified in th e liver, representing approximate to 50% of hepatocytes for albumin mRNA an d approximate to 61% for protein. At 2 months' posttransplantation, cells e xpressing albumin mRNA represented approximate to 77% of hepatocyte mass, a nd cells expressing albumin protein represented approximate to 81% of total hepatocyte mass. Hepatocyte-transplanted NAR also exhibited normal or near -normal serum albumin levels (3.0 +/- 0.2 g/dL), High levels of serum album in were sustained for the 2-month duration of experiments. These results de monstrate the ability of this protocol for hepatocyte transplantation to re store a major biosynthetic and physiological function of the liver, and sug gest its potential use as a method to treat genetic-based or acquired liver diseases.