Expanded Primary Hepatocytes: Achieve More Predictive Toxicity StudiesJan 30, 2020 at 12:00 PM ET
Choosing the ideal model for toxicological research and screening poses a challenge to the researcher. On one hand, you want the high biological relevance of a primary cell so you can trust that your assay is predictive of the in vivo situation. On the other, you need the proliferative capacity of a cell line to provide a copious quantity of cells so you can test all of your variable conditions. ATCC upcyte Hepatocytes provide both qualities. This advanced hepatic model exploits a growth method that directs non-dividing primary cells to proliferate without altering their biological properties, allowing for the generation of large batches of homogeneous yet physiologically relevant hepatocytes. This webinar will provide an overview of upcyte Hepatocytes, highlighting the various uses for the cells, such as hepatoxicity prediction and drug-drug interaction studies.
- Toxicologists need the high biological relevance of primary cells and the proliferative capacity of cell lines for standard, predictive assays; neither model provides both characteristics.
- upcyte technology offers sufficient quantities of hepatocytes that exhibit primary cell physiologies such as CYP activity. Long-term culturing is possible to detect low level hepatotoxicity.
- upcyte Hepatocytes are fully characterized with validated performance data, and they are tested for CYP induction and inhibition.
Kevin Grady, BS
Senior Product Line Business Manager, ATCC
Kevin Grady is the Senior Product Line Business Manager for Cell Biology at ATCC. He has been with ATCC for 8 years; prior to ATCC, he held positions at Lonza as Worldwide Product Manager and Director of Scientific Support. Kevin has a long history in the life science industry additionally serving as Director of Scientific Support at Amaxa and Manager of Technical Support at Life Technologies. Mr. Grady has always found great satisfaction in helping researchers learn how to use available products and tools to be more productive and successful in reaching their research goals.
Are upcyte hepatocytes immortalized?
No, upcyte Hepatocytes have a finite lifespan. They will proliferate and retain a differentiated phenotype for up to 40 population doublings. After this time, they exhibit senescence genes. upcyte Hepatocytes do not exhibit anchorage-independent growth and will not form colonies in soft agar.
Can I passage the upcyte hepatocytes?
No, the cells are already at the last population doublings possible. You can plate the cells at a density as low as 25% confluence to achieve 100% confluence after 4 days (i.e., 2 population doublings) but that is all. Further expansion will lead to the cells expressing senescence genes and the phenotype is lost. To obtain cells which you can expand in your lab, you will need the Master cell bank cells, which are at a lower population doubling number.
Can I use upcyte hepatocytes for cytotoxicity assays?
Yes. The lab at upcyte has tested the toxicity of over 30 compounds in upcyte Hepatocytes from four donors using MTS metabolism, cellular ATP and LDH contents as measurements of toxicity. These data show that upcyte Hepatocytes are able to predict whether test compounds are hepatotoxic or non-hepatotoxic. These studies also showed that the intra- and inter-experimental reproducibility is very good.
How do you maintain the activities of drug metabolizing enzymes?
The differentiated state of the cells is inherent to upcyte Hepatocytes and they do not need special ingredients such as DMSO to increase activities. As with primary human hepatocytes, the scientists at upcyte have shown that the AhR, CAR and PXR expression is increased placing the cells into 3-D culture. As a result, the expression and activities of CYPs (such as CYP1A, CYP2B6 and CYP3A4) are also increased by culturing upcyte Hepatocytes in 3-D scaffolds.
What is the population doubling and how does it differ from the passage number?
A population doubling is when the number of cells increases by 2-fold. The population doubling time is the time that it takes to expand the cell number by two (which is 48 h for upcyte Hepatocytes). A passage is the act of removing cells at a high confluence from a culture plate (e.g., by trypsin) and seeding them out a lower confluence. The passage number is therefore the number of times the cells have been trypsinized for further expansion. The number of cells my multiply by more than two between passages.