Research
Research themes in the department of Hepatology
Cell lines
HepaRG
The human HepaRG hepatic cell line has emerged as a potential surrogate to PHHs for pre‐clinical hepatotoxicity assays. HepaRGs are an intrinsic, terminally differentiated co‐culture of hepatocyte‐ and cholangiocyte‐like cells containing many functional and phenotypic similarities with PHH. These cells were procured from a young adult female with hepatocarcinoma and concurrent hepatitis C. Though an immortalized cell line, it retains a stable phenotype for up to 21 passages. HepaRGs are a highly reproducible cell line, without the donor variability seen in PHHs, and as such ensure a consistent and relevant model. HepaRG cells retain some of the major CYP450 pathways and Phase II enzymes as well as the production of glucose/glycogen and urea . These cells also show functional polarity, a hallmark of maturity and in vivo hepatocyte organization, with intact Phase III drug transporters. These properties are generally not evident in ‘standard’ human hepatic cell lines monocultures.
HepG2/C3A
C3A cells are a clonal derivative of HepG2. They are a single cell culture of hepatocytes procured from a caucasian male and exhibit high albumin production, AFP and ability to grow in a glucose deficient medium. C3A cells retain some CYP activity and are transfectable.
Caco2
Caco2 cells are a human epithelial colorectal adenocarcinoma cell line. Morphologically and phenotypically these cells simulate enterocytes from the lining of the small intestine. These cells are often used as a barrier model for determining drug permeability and absorption.
Techniques
ECIS
There are various different platforms available to measure cellular impedance (TEER, CNBIO, xCelligence™, CellKey™ and Bionas Discovery). However, none of these systems are capable of the mathematical modelling and sensitivity of the AB Biosciences ECIS Z theta™. This system is capable of measuring total impedance over time and then deconvolving this data into biologically relevant components measuring specifically: tight junctions (Rb), basolateral adhesion (a) and overall membrane integrity (Cm). This is achieved by measuring impedance on a multiple frequency setting which can identify the different pathways the current can take. By alternating the frequency of the current between low (<10kHz) and high (>40kHz) it allows for a measurement of changes of impedance or resistance which indicates how well cells have adhered to the substrate as well as a measurement of cell-cell interaction or tight junctions [1,2].
1. Wegener, J, Keese, CR, Giaever, I., 2000. Electric cell-substrate impedance sensing (ECIS) as a noninvasive means to monitor the kinetics of cell spreading to artificial surfaces. Experimental Cell Research 259:158-166
2. Giaever, I. and Keese CR., 1991. Micromotion of mammalian cells measured electrically. Natl. acad Sci 88:7896-7900