Introduction: Hepatocyte transplantation is an attractive alternative to whole organ transplant for patients suffering chronic or acute liver failure and metabolic liver diseases. However, there is a severe shortage of suitable donor organs for hepatocyte isolation. Hepatocyte-like cells (HLC) derived from stem cells may serve as an alternative. Due to easy accessibility and abundant supply, placental derived human amniotic epithelial cells (hAEC) are preferred for HLC generation, especially since they possess features of hepatic progenitors. To prevent allograft rejection, cells can be encapsulated. Since HLC are immunogenic, the aim of this study was to determine effects of encapsulation on HLC functions.
Methods: hAEC (n=4-6) were differentiated into HLC for 4 weeks and evaluated for hepatocyte-specific gene expression and functions. HLC were encapsulated in barium alginate microcapsules using an air-driven droplet generator. The effect of encapsulation and the three dimensional environment on viability, function and hepatocyte related gene expression were compared with monolayer cultures.
Results: Compared with naïve hAECs, differentiated cells performed key functions of hepatocytes including urea synthesis, drug metabolising cytochrome P450 CYP3A4 activity, low-density lipoprotein (LDL) uptake, nuclear localisation of the transcription factor hepatocyte nuclear factor 4-alpha and hepatocyte related gene expression for cholesterol (ABCA2 and CYP7A1) and xenobiotic metabolism (EPHX and SLC27A2). Upon encapsulation, > 85% remained viable for at least 7 days in culture compared to monolayer HLC. Encapsulated HLC showed increased CYP3A4 activity, LDL uptake and urea synthesis. Anti-oxidative capacity of encapsulated HLC was maintained, as measured by high levels of total and oxidised glutathione. Further, there was increased mRNA expression of genes implicated in cholesterol (ABCA1, CYP7A1), fat (ACOX2) and xenobiotic (HAMP) metabolism.
Conclusion: HLC can be encapsulated without loss of viability or function. Further testing of encapsulated HLC derived from hAEC in animal models to assess their efficacy in rescuing liver failure is warranted.