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Three-dimensional culture of human embryonic stem cell derived hepatic endoderm and its role in bioartificial liver construction.

Sharma R, Greenhough S, Medine CN, Hay DC - J. Biomed. Biotechnol. (2010)

Bottom Line: The impairment of liver functions has serious implications and is responsible for high rates of patient morbidity and mortality.The major hindrance in the development of bioartificial liver devices and cellular therapies is the limited availability of human hepatocytes.Therefore, the use of human embryonic stem cell-derived hepatic endoderm in combination with tissue engineering has the potential to pave the way for the development of novel bioartificial liver devices and predictive drug toxicity assays.

View Article: PubMed Central - PubMed

Affiliation: Medical Research Council Centre for Regenerative Medicine, University of Edinburgh, 49 Little France Crescent, Edinburgh,Scotland EH16 4SB, UK.

ABSTRACT
The liver carries out a range of functions essential for bodily homeostasis. The impairment of liver functions has serious implications and is responsible for high rates of patient morbidity and mortality. Presently, liver transplantation remains the only effective treatment, but donor availability is a major limitation. Therefore, artificial and bioartificial liver devices have been developed to bridge patients to liver transplantation. Existing support devices improve hepatic encephalopathy to a certain extent; however their usage is associated with side effects. The major hindrance in the development of bioartificial liver devices and cellular therapies is the limited availability of human hepatocytes. Moreover, primary hepatocytes are difficult to maintain and lose hepatic identity and function over time even with sophisticated tissue culture media. To overcome this limitation, renewable cell sources are being explored. Human embryonic stem cells are one such cellular resource and have been shown to generate a reliable and reproducible supply of human hepatic endoderm. Therefore, the use of human embryonic stem cell-derived hepatic endoderm in combination with tissue engineering has the potential to pave the way for the development of novel bioartificial liver devices and predictive drug toxicity assays.

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Schematic diagram of 3D culture of hepatocytes on a polymer scaffold, and the potential applications of this technology.
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fig2: Schematic diagram of 3D culture of hepatocytes on a polymer scaffold, and the potential applications of this technology.

Mentions: The major limitation of tissue engineering methodologies is poor simulation of the complex architecture and abundant vasculature of the liver. In vivo, cells at a distance of more than 0.1mm from vascularity cannot survive and cells within bioengineered tissue have similarly stringent requirements, as diffusion within scaffolds is limited to a few hundred micrometers [126]. Poyck et al. [127] have shown in an AMC bioartificial liver model that long-term culture of primary porcine hepatocytes is improved by increased anaerobic glycolysis, which leads to better liver specific function and metabolic stability. For this reason, in high density liver cultures adequate delivery of oxygen to cells is crucial. Synthetic oxygen carriers such as perflurocarbons and cross-linked hemoglobin have been added onto scaffolds to facilitate oxygenation [128]. The latest approach has been the use of oxygen generating biomaterials, and it was reported that PLGA scaffolds containing calcium peroxide-based particles maintained elevated levels of oxygen and extended cell viability under hypoxic conditions [129]. Microfabrication and computational fluid dynamics have also been used to generate scaffold designs suitable for microvasculature and organ specific constructs [130–132]. Carraro et al. [133] demonstrated a microfluidics-based bilayer device with discrete parenchymal chambers designed using computational modelling. This device was able to sustain human hepatoma cells, and primary rat hepatocytes. By solving the problem of supplying cells grown in 3D tissue culture with oxygen, it will be possible to sustain the culture of hepatocytes in vitro for extended periods, facilitating cell studies and eventually leading to the improved functionality of BALs (Figure 2).


Three-dimensional culture of human embryonic stem cell derived hepatic endoderm and its role in bioartificial liver construction.

Sharma R, Greenhough S, Medine CN, Hay DC - J. Biomed. Biotechnol. (2010)

Schematic diagram of 3D culture of hepatocytes on a polymer scaffold, and the potential applications of this technology.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2821762&req=5

fig2: Schematic diagram of 3D culture of hepatocytes on a polymer scaffold, and the potential applications of this technology.
Mentions: The major limitation of tissue engineering methodologies is poor simulation of the complex architecture and abundant vasculature of the liver. In vivo, cells at a distance of more than 0.1mm from vascularity cannot survive and cells within bioengineered tissue have similarly stringent requirements, as diffusion within scaffolds is limited to a few hundred micrometers [126]. Poyck et al. [127] have shown in an AMC bioartificial liver model that long-term culture of primary porcine hepatocytes is improved by increased anaerobic glycolysis, which leads to better liver specific function and metabolic stability. For this reason, in high density liver cultures adequate delivery of oxygen to cells is crucial. Synthetic oxygen carriers such as perflurocarbons and cross-linked hemoglobin have been added onto scaffolds to facilitate oxygenation [128]. The latest approach has been the use of oxygen generating biomaterials, and it was reported that PLGA scaffolds containing calcium peroxide-based particles maintained elevated levels of oxygen and extended cell viability under hypoxic conditions [129]. Microfabrication and computational fluid dynamics have also been used to generate scaffold designs suitable for microvasculature and organ specific constructs [130–132]. Carraro et al. [133] demonstrated a microfluidics-based bilayer device with discrete parenchymal chambers designed using computational modelling. This device was able to sustain human hepatoma cells, and primary rat hepatocytes. By solving the problem of supplying cells grown in 3D tissue culture with oxygen, it will be possible to sustain the culture of hepatocytes in vitro for extended periods, facilitating cell studies and eventually leading to the improved functionality of BALs (Figure 2).

Bottom Line: The impairment of liver functions has serious implications and is responsible for high rates of patient morbidity and mortality.The major hindrance in the development of bioartificial liver devices and cellular therapies is the limited availability of human hepatocytes.Therefore, the use of human embryonic stem cell-derived hepatic endoderm in combination with tissue engineering has the potential to pave the way for the development of novel bioartificial liver devices and predictive drug toxicity assays.

View Article: PubMed Central - PubMed

Affiliation: Medical Research Council Centre for Regenerative Medicine, University of Edinburgh, 49 Little France Crescent, Edinburgh,Scotland EH16 4SB, UK.

ABSTRACT
The liver carries out a range of functions essential for bodily homeostasis. The impairment of liver functions has serious implications and is responsible for high rates of patient morbidity and mortality. Presently, liver transplantation remains the only effective treatment, but donor availability is a major limitation. Therefore, artificial and bioartificial liver devices have been developed to bridge patients to liver transplantation. Existing support devices improve hepatic encephalopathy to a certain extent; however their usage is associated with side effects. The major hindrance in the development of bioartificial liver devices and cellular therapies is the limited availability of human hepatocytes. Moreover, primary hepatocytes are difficult to maintain and lose hepatic identity and function over time even with sophisticated tissue culture media. To overcome this limitation, renewable cell sources are being explored. Human embryonic stem cells are one such cellular resource and have been shown to generate a reliable and reproducible supply of human hepatic endoderm. Therefore, the use of human embryonic stem cell-derived hepatic endoderm in combination with tissue engineering has the potential to pave the way for the development of novel bioartificial liver devices and predictive drug toxicity assays.

Show MeSH
Related in: MedlinePlus