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Pressure builds against foetal calf serum for in vitro tests

Funding organisations should make a stand against in vitro tests using foetal calf serum (FCS), according to the director of the 3Rs Centre, Utrecht Life Sciences in the Netherlands.

Also known as foetal bovine serum, FCS is the liquid fraction of clotted blood collected from the hearts of living foetuses. It contains embryonic growth promoting factors and is used to feed cells in vitro. FCS problems are well documented but the serum is still widely used.

"There are two main issues identified in using FCS: animal welfare and several scientific problems," said Jan van der Valk, director of the 3Rs Centre. On the science side, FCS composition varies between batches, affecting test reproducibility. "Not all scientists, or serum producers, wish to acknowledge welfare issues related to collecting blood from the unborn calf for serum production," he added.

The US Food and Drug Administration, European Medicines Agency, OECD and EU Reference Laboratory for Alternatives to Animal Testing (EURL Ecvam) all discourage FCS use.

However, "more official organisations, and in particular funding organisations, should apply the 'no FCS' rule," said Dr van der Valk. He also called for journals to ask authors to justify its use.

Serum-free alternatives

The "main obstacle" for scientists wishing to switch to serum-free media is that unlike FCS, most are cell specific, said Dr van der Valk. This is reiterated by the OECD's guidance document (GD) on good in vitro method practices (Givimp), which states that they need to be selected and optimised for a selected cell type. The document also says that recipes for commercially available serum-free media tend to be proprietary.

The Givimp GD highlights the 3Rs Centre's FCS-free database, which was launched in August 2017 and now attracts around 400 unique visitors per month from all over the world.

"It costs time and money to develop a serum-free, chemically defined medium for your cells. That’s why we have developed the database: to facilitate the search for serum-free media for your specific cell types," Dr van der Valk told Chemical Risk Manager.

The database holds information on FCS-free media for 260 different cell types. Media are either commercially available, sometimes with modifications, or are 'self-manufactured' by individual labs.

Scientists can add comments and formulations to the database, and Dr van der Valk encourages discussions on optimal serum formulations for a given cell type, "making it a database for the scientists, by the scientists".

The FCS-free database team has been shortlisted for a Lush prize for training. Furthermore, all prize nominees have been asked to declare any use of FCS. Prize winners will be announced on 16 November.

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