Eighteen donors.
Fiftyfold difference.
Every Cytochroma cell product is manufactured from a bank of human iPSC donor lines with recorded ancestry, sex, age band and disease status.
Across six lines characterised under a single protocol, baseline CYP3A4 activity varied more than fiftyfold.
The panel
Full donor list
Ancestry is reported as proportional composition against African, European and Native American reference components. Percentages are rounded. Gaps in HLA and CYP columns are shown as gaps.
Cytochroma iPSC donor lines, current as of 24 July 2026
LINE
SEX
AGE
AFR
EUR
NAM
Ancestry
STATUS
HLA
CYP
i2F
F
35–74
24
72
4
Healthy
TYPED
CHAR
i3M
M
35–74
19
78
3
Healthy
TYPED
CHAR
i4F
F
35–74
45
53
3
Healthy
—
—
i5M
M
35–74
2
95
3
Healthy
—
—
i7F
F
35–74
32.3
60
7.6
Healthy
TYPED
—
i8M
M
35–74
55.1
37.8
7.1
Healthy
TYPED
CHAR
i15F
F
70s
31.9
56.3
11.8
Healthy
—
—
i16M
M
50s
39.2
14.2
46.7
Healthy
—
—
i18F
F
50s
19.2
24.4
56.5
Healthy
TYPED
CHAR
i20M
M
50s
42.7
50.6
6.7
Healthy
—
—
i21M
M
40s
14.9
77.3
7.8
MARFAN
—
—
i22M
M
50s
25.2
55.5
19.4
MARFAN
—
—
i23F
F
60s
46.3
45.1
8.6
Healthy
—
—
i26F
F
50s
34.9
56.8
8.3
Healthy
TYPED
—
i28M
M
70s
8.2
77.7
14.1
Healthy
—
—
i29F
F
50s
10.4
45.2
44.4
Healthy
—
—
i30F
F
60s
26.9
45.4
27.7
Healthy
TYPED
CHAR
i31M
M
60s
1.6
72.7
25.7
Healthy
TYPED
CHAR
AFR · African ancestry EUR · European ancestry NAM · Native American ancestry
TYPED · HLA typed at four-digit resolution, nine loci CHAR · CYP450 expression and activity characterised
Most preclinical hepatotoxicity data is generated in a small number of near-identical cell lines. That is one reason compounds clear preclinical testing and then fail in real, diverse patient populations. This panel is built so a compound can be tested across genuine human variation before it reaches the clinic.
Two lines carry Marfan syndrome (i21M, i22M), available for cardiovascular disease modelling alongside our cardiomyocyte and cardiac fibroblast products.
FUNCTIONAL CHARACTERISATION
CYP450 activity, measured
Six lines have been characterised for cytochrome P450 expression and enzymatic activity under a single manufacturing protocol. Activity was measured with luciferin-based probe substrates and normalised to incubation time and total RNA content.
CYP1A2 activity, fold induction by omeprazole
50 μM, 48 h · n=3 per condition
i8M
9.4×
i31M
9.4×
i30F
7.5×
i2F
6.1×
i3M
5.0×
i18F
2.5×
CYP1A2 activity was inducible in every line tested, confirming that aryl hydrocarbon receptor signalling is intact and functional. Basal CYP1A2 activity was detected in all six lines and varied approximately ninefold between the highest and lowest donor.
Transcripts for CYP1A2, CYP2B6, CYP2C8, CYP2C9, CYP2C19 and CYP3A4 were all detected by TaqMan qPCR. Full study report available under CDA.
Frequently asked
Questions we get asked,
answered.
Straight answers on iPSC-derived cell models, CYP450 activity, donor diversity and the regulatory shift toward New Approach Methodologies. Where we do not yet have data, we say so.
Cell models
01.1
What are iPSC-derived hepatocytes used for?
iPSC-derived hepatocytes are human liver cells grown from reprogrammed donor cells. They are used to screen for drug-induced liver injury, study drug metabolism and CYP450 activity, model liver disease such as MASH, and replace animal testing in preclinical safety work.
01.2
How do iPSC-derived hepatocytes compare to primary human hepatocytes?
Primary human hepatocytes come from donated livers: physiologically authentic, but scarce, variable between batches and rapidly dedifferentiating in culture. iPSC-derived hepatocytes are renewable, reproducible and available in matched donor panels, though typically less metabolically mature.
01.3
How do iPSC-derived hepatocytes compare to HepG2 and HepaRG?
HepG2 and HepaRG are immortalised cell lines derived from single tumour donors. They are reproducible and convenient but capture no population variation and diverge from primary hepatocyte biology. iPSC-derived hepatocytes are renewable, donor-matched and available as multi-donor panels spanning real human genetic variation.
01.4
What cell types can be combined into a multicellular liver model?
A multicellular liver model typically combines hepatocytes with Kupffer cells for inflammation, hepatic stellate cells for fibrosis, and liver sinusoidal endothelial cells for barrier and transport function. Cholangiocytes can be added for bile duct biology.
01.5
How is a MASH or steatosis model built in vitro?
Steatosis is induced by dosing hepatocyte models with free fatty acids such as oleate and palmitate, often alongside high glucose or insulin. Adding Kupffer and stellate cells recreates the inflammation and fibrosis that define MASH.
Drug metabolism
02.1
Do CYP450 enzyme levels vary between iPSC donor lines?
Substantially. In a six-line characterisation study, baseline CYP3A4 activity varied more than fiftyfold between healthy human donors under identical culture and manufacturing conditions. A compound cleared rapidly by one donor’s hepatocytes may accumulate in another’s.
02.2
Do iPSC-derived hepatocytes have functional CYP450 activity?
Yes. Cytochroma iPSC-derived hepatocytes show measurable basal enzymatic activity for CYP1A2 and CYP3A4, quantified using luciferin-based probe-substrate assays and normalised to total RNA content. Transcripts for CYP1A2, CYP2B6, CYP2C8, CYP2C9, CYP2C19 and CYP3A4 are all detectable by qPCR.
02.3
Can CYP450 enzymes be induced in iPSC-derived hepatocytes?
Yes for CYP1A2. Omeprazole treatment increased CYP1A2 enzymatic activity between 2.5-fold and 9.4-fold across six donor lines, confirming that aryl hydrocarbon receptor signalling is intact and functional. Induction via the pregnane X receptor pathway is under further investigation.
02.4
What is the difference between CYP450 expression and CYP450 activity?
Expression measures how much enzyme messenger RNA a cell produces. Activity measures whether the resulting enzyme actually metabolises a substrate. The two do not always agree, and activity is the readout that predicts what a drug will do, so both should be reported.
02.5
Which Cytochroma donor lines are best for drug metabolism studies?
Lines i2F and i30F show the highest combined CYP450 expression and activity in internal characterisation, making them the usual first choice where a strong metabolic component is required. Where the objective is to capture inter-donor variability rather than maximise signal, a multi-line panel is recommended.
Donors and HLA
03.1
Why does donor diversity matter in preclinical toxicity testing?
Drug metabolism varies between individuals, driven by genetic variation in cytochrome P450 enzymes and transporters that differs across ancestral populations. Testing a single cell line gives an average that can miss toxicity affecting specific groups, contributing to late-stage clinical failure.
03.2
Are Cytochroma donor lines HLA-typed?
Eight of eighteen lines are typed at four-digit resolution across nine loci: HLA-A, HLA-B, HLA-C, DRB1, DRB3/4/5, DQA1, DQB1, DPA1 and DPB1. Full haplotype data is supplied to customers under a material transfer agreement rather than published openly.
03.3
What is HLA typing and why does it matter for cell models?
HLA typing identifies the immune-recognition genes a donor carries. For cell models it matters when studying immune response, inflammation or cell therapy compatibility, and it lets researchers deliberately match or vary immune background across a donor panel.
03.4
How is donor ancestry determined for Cytochroma iPSC lines?
Ancestry is reported as proportional composition against African, European and Native American reference components, derived from genotype data. Percentages describe genetic composition and are not a substitute for self-reported identity.
Regulatory and NAMs
04.1
What is a New Approach Methodology (NAM)?
A New Approach Methodology is any non-animal technique used to assess drug safety or efficacy, including human cell models, organoids, organ-on-chip systems and computational modelling. Regulators now accept NAM data in place of some animal studies.
04.2
How does the FDA Modernization Act affect preclinical drug testing?
The FDA Modernization Act 2.0 (2022) removed the legal requirement that new drugs be tested in animals, permitting cell-based and computational alternatives. The FDA’s 2025 roadmap and 2026 draft NAM guidance set out how to use them.
As of July 2026, the FDA Modernization Act 3.0 has passed the House and awaits Senate approval of the House-passed text. It would require the FDA to remove remaining animal-testing references from its own regulations. Status current as at [DATE].
Ordering
05.1
Where can I buy ancestrally diverse iPSC-derived cells?
Cytochroma supplies ancestrally diverse, HLA-typed human iPSC-derived cells from its Edinburgh facility, including hepatocytes, cardiomyocytes, Kupffer cells, hepatic stellate cells and endothelial cells. Order directly at cytochroma.org, or through Scientist.com and Science Exchange.
05.2
How long does it take to receive cells from Cytochroma?
Banked cell types ship within 96 hours of order confirmation for UK and EU destinations, and 7 days internationally. Custom or made-to-order cell types have a lead time of 6-8 weeks. Contact info@cytochroma.org to confirm current stock.
05.3
Can Cytochroma make a custom cell type or donor line?
Yes. Alongside banked stock, Cytochroma undertakes custom differentiation and can generate specific cell types or donor genotypes to order. Typical projects run 10-12 weeks from specification. Contact info@cytochroma.org with your requirements.
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