Expansion of human hepatocyte populations by a retroviral gene transfer of simian virus 40 large T antigen

Bioartificial livers: a review of their design and manufacture

Acute liver failure (ALF) is a rapidly progressive disease with high morbidity and mortality rates. Liver transplantation and artificial liver support systems, such as artificial livers (ALs) and bioartificial livers (BALs), are the two major therapies for ALF. Compared to ALs, BALs are composed of functional hepatocytes that provide essential liver functions, including detoxification, metabolite synthesis, and biotransformation. Furthermore, BALs can potentially provide effective support as a form of bridging therapy to liver transplantation or spontaneous recovery for patients with ALF. In this review, we systematically discussed the currently available state-of-the-art designs and manufacturing processes for BAL support systems. Specifically, we classified the cell sources and bioreactors that are applied in BALs, highlighted the advanced technologies of hepatocyte culturing and bioreactor fabrication, and discussed the current challenges and future trends in developing next generation BALs for large scale clinical applications.

Transplantation of encapsulated hepatocytes during acute liver failure improves survival without stimulating native liver regeneration

The aim of this study was to evaluate the effects of intraperitoneal transplantation of encapsulated human hepatocytes on liver metabolism and regeneration of mice with acute liver failure. Primary human hepatocytes were immortalized using lentiviral vectors coding for antiapoptotic genes and microencapsulated using alginate-polylysine polymers. In vitro, immortalized human hepatocytes showed low, but stable, synthetic and catabolitic functions over time, when compared to primary hepatocytes. In vivo, mice with acute liver failure and transplanted with encapsulated immortalized human hepatocytes had a significantly improved survival and biochemical profile, compared to mice transplanted with empty capsules. Serum levels of cytokines implicated in liver regeneration were lower in mice transplanted with hepatocytes compared to mice receiving empty capsules. This decrease was significant for IL-6 and HGF at 3 h. Measurement of liver regeneration showed no significant difference between mice transplanted with hepatocytes compared to control groups. Intraperitoneal transplantation of encapsulated immortalized hepatocytes significantly improved survival of mice with acute liver failure by providing metabolic support and without modifying liver regeneration. The lower levels of cytokines implicated in liver regeneration suggest that the metabolic support provided by the encapsulated hepatocytes reduced the inflammatory stress on the liver and herein decreased the regenerative trigger on residual hepatocytes. These data emphasize that metabolic function and regeneration of hepatocytes are two distinct aspects that need to be studied and approached separately during acute liver failure.

Cellular Transplantation for Liver Diseases

Presently, the orthotropic liver transplantation (OLT) is still the most effective therapeutic for patients with acute or chronic hepatic failure. However, due to the shortage of donor livers, the number of patients benefited from this approach is limited. Therefore, some alternative modalities have been paid attention for restoring the liver function. The cell transplantation is one of the promising modalities to realize this purpose. The types of cells used in the cell transplantation include syngeneic hepatocytes, allogeneic hepatocytes, immortalized hepatocytes, and stem cells derived heptocytes. The stem cells, especially the adult stem cells from bone marrow, are shown as a promising cell source for liver repopulation. The mesenchymal bone marrow stem cells and embryonic stem cells can be induced to differentiate into the hepatic lineage and might be used in the cell transplantation for liver diseases. Compared to OLT, the advantages of cell-based therapy for liver disease are, but not limited to, less invasive, less expensive, easy manipulated, easy expansion of cells in vitro. Cells can be stored in a cell bank for future use. Though most of the current studies are experimental and animal based, the cellular therapy for liver disease is expected to be an effective alternative in clinical settings in near future.

Gene transfection for rat primary cultured hepatocytes

AIM: To study the efficient and stable gene transfection method of rat primary cultured hepatocytes by liposome.

METHODS: Rat hepatocytes were isolated by collegenase perfusion, and the pEGFP-N₃ plasmid containing GFP and Neo gene was transfected into rat primary hepatocyte with liposome. The expression of GFP and Neo was observed by fluorescence microscopy and in situ hybridization.

RESULTS: The rate of live hepatocytes obtained was 95%. Under fluorescence microscope, hepatocyte transfected with pEGFP-N₃ plasmid showed green fluorescence. By using in situ hybridization method, expression of Neo gene was observed in hetpatocyte transfected with pEGFP-N₃.

CONCLUSION: Rat hepatocyte can be transfected by pEGFP-N₃. pEGFP-N₃ expression vector and makes it easy to assess the expression of target gene in transfected hepatocyte, and it can be used for localization of transplantated hepatocyte.