Bioartificial livers containing porcine hepatocytes, with a hollow fibre bioreactor are already used in the clinic as supportive devices, allowing the patients liver to regenerate properly upon acute liver failure, or to bridge the individual's liver functions until a transplant is possible. This application seeks to employ this technology for in vitro to in vivo extrapolation of systemic chemical toxicity.
The scientific/technical basis of the project led by Dr Steven Webb from Liverpool John Moores University is the combination of a unique mix of tissue engineering/bioreactor development with mechanism‐based toxicology. This will be underpinned by mathematical (mechanistic) modelling and systems biology (data led modelling), which can both help direct research and develop a model for extrapolation of the in vitro findings to in vivo systems. The application will define the physiological & pharmacological response of primary hepatocytes and human hepatic cell lines in a bioreactor. Should this approach prove successful, later models will incorporate co‐culture and multi‐tissue bioreactors in series. Incorporation of features such as 3D cell architecture, vectorial liquid flow & oxygen gradients are favourable for liver zonation enhancing xenobiotic metabolism & pharmacokinetics / biomarker assessment. The project will predominantly focus upon the development of the hepatocyte compartment as metabolic capability here is crucial for assessing effects of metabolites. The project will be underpinned and informed by a strong mathematical modelling/systems biology approach that will form a data framework consisting of circulating drug and metabolite levels, tissue/cellular burden of metabolites, glutathione and covalent binding levels, adaptive response (Nrf2/NFkB nuclear translocation), apoptosis and necrosis biomarkers, this would allow more accurate in vitro to in vivo extrapolation to both animals and man.
Full details about this CRACK IT Challenge can be found on the CRACK IT website.
Reddyhoff D et al. (2015). Timescale analysis of a mathematical model of acetaminophen metabolism and toxicity. JTB 386:132-146. doi:10.1016/j.jtbi.2015.08.021
A multi-disciplinary team led by Dr Steven Webb, Liverpool John Moores University, has developed a zonated hollow fibre bioreactor (HFB) that more closely replicates the architecture and physiology of the liver for toxicology testing (Storm et al., 2016). The system incorporates physiologically relevant 3D cell architecture, continuous fluid flow and oxygen gradients to promote liver zonation.
Mathematical modelling played a large role in the development of the HFB, for example, in predicting the optimal operating conditions of the HFB to best recapitulate the zonated liver physiology, and reduced development time by approximately six to twelve months. The exact design may not have been reached at all without the mathematical modelling.
The system is composed of a borosilicate glass module fitted with three plasma treated porous polystyrene fibres (Figure 1). Hepatocytes are seeded onto the outer fibre wall and the lumen of the fibre acts as the sinusoid (blood vessel) through which media is perfused. There is an oxygen gradient along the fibres to promote liver zonation. The junctions between the cells and the extracapillary space around the outside of the fibres then act as a bile canaliculi compartment.
The system has been optimised using the HepG2/C3A cell line and compared to 2D static monolayer cultures. Based on the analysis of multiple morphological and functional parameters, the HFB is an improved model system for HepG2/C3A cells (Storm et al., 2016).
The next steps are to further validate the system with primary heptocytes and a wider range of compounds, plus to manufacture an easy-to-use prototype device for user trial.
For further information about the HFB system please contact Dr Steven Webb.
Figure 1. Schematic of the hollow fibre bioreactor.
Contractor(s)Dr Dominic Williams
University of Liverpool