Switching to FCS-free media: worth the effort

While the 3Rs Centre Utrecht is stimulating in vitro research to reduce the dependance of biomedical research on experimental animals, many in vitro methods rely on fetal calf serum (FCS) as a cell culture supplement. However, the use of FCS is accompanied by ethical and many scientific concerns . Bart Hameete, from Utrecht University's Department of Pharmacology, was motivated to find alternatives to FCS to culture human trophoblast cells (HTR8/SVneo) during his PhD journey. 

Investigating placental function

As an extravillous trophoblast cell line, HTR8/SVneo cells are used to answer questions related to placentation and placental vasculature, often in the context of pregnancy complications such as miscarriage or pre-eclampsia.

The invisible use of animal-derived components

Bart, initially drawn to in vitro methods for their perceived animal-free nature, was surprised to discover the widespread reliance on the animal-derived FCS in cell culture. This unexpected revelation motivated him to explore ways to truly eliminate animal-derived components from his research. "When I first incorporated an in vitro component in my then primarily in vivo project, I thought one of the big selling points of this addition would be that it was completely animal-free”, Bart says. “I was surprised to learn that a lot of in vitro research is in fact not animal-free. I felt a little cheated and wondered what it would take to make my research genuinely free from animal suffering. This opened a rabbit hole that eventually led to the research we're discussing.”

Making the switch: from FCS to human platelet lysate

Determined to make his research more animal-free, Bart explored human platelet lysate (HPL) as a potential alternative to FCS. His approach was straightforward: switching the cells from an FCS-containing medium to an HPL-based medium in one step. “The act of switching the cells itself isn’t particularly difficult,” Bart explained. “To increase your chances of success, you transition gradually over a few weeks, and it should work for most cell types. The real challenge is figuring out which medium composition actually supports cell growth, and proving that it works." To ensure the HPL-based medium was a viable alternative, Bart systematically evaluated key parameters such as cell viability, proliferation, and cytokine release.

While the cells adapted quickly, Bart emphasizes the importance of an adaptation period before running experiments. “Regardless of how you switch your cells, I’d advise against conducting experiments in the first few weeks after switching to 100% FCS-free medium. Allowing time for adaptation helps to prevent variability in results.”

Was it worth it?

Reflecting on the experience, Bart acknowledges that while he hasn’t had the opportunity to fully assess how the switch to HPL impacts overall research quality, he believes the change was worthwhile. “This research was conducted towards the end of my PhD, so we couldn’t extensively compare the long-term effects of HPL use. However, the medium is more humanized, standardized, and— also important—cheaper. The potential to improve research reliability for others is substantial, and for that reason alone, I’d say this was worth the effort.”

His research is now in the final stages of publication, and we are eagerly looking forward to seeing his completed work contribute to the growing body of knowledge on FCS-free cell culture.

The 3Rs Centre Utrecht: supporting transitions

At the 3Rs Centre Utrecht, we are happy to see young researchers like Bart take the initiative to move towards more animal-free research. His story demonstrates that making the switch to FCS-free culture is not only possible but can also bring benefits in terms of standardization and human relevance. We hope his experience will inspire others to explore similar alternatives.

To support researchers in this transition, we offer several resources, including the Gels & Sera working group and our FCS-free database where you can find animal-free alternatives to FCS and see if they fit your setup. Additionally, we provide practical tips on our website and are always happy to answer any specific inquiries via email.

If you're considering making the switch, don’t hesitate to reach out, we are here to help!