Serum-free media contribute to better reproducibility in in vitro research

Abstract: Reproducibility has become a major issue in the discussion of validity of scientific results. The recently drafted OECD ‘guidance document on Good In Vitro Method Practices (GIVIMP) for the development and implementation of in vitro methods for regulatory use in human safety assessment’1, identified and discusses several factors that contribute to this lack of reproducibility in in vitro methods. One of the factors identified is the use of foetal bovine serum (FBS), which is still being applied as the universal medium supplement to grow and maintain cells and tissues. But, the use of FBS has also been regarded critically for decades. The use of FBS presents four significant issues: (i) the degree of suffering experienced by the calf during blood collection2; (ii) inappropriate cellular growth profiles and physiological responses of cells; (iii) FBS contamination with viruses, prions, etc.; (iii) the large variability of FBS such that it is very difficult to even ensure consistent and well controlled in vitro cell culture between batches; (iv) the fraud-problem3. Nevertheless, to date, FBS is used at a large scale, despite several attempts to develop FBS-free media. Recent years showed that human platelet lysates (HPLs) can be a valuable alternative to FBS as cell culture supplement. In addition, for several applications, there is large interest in chemically-defined media4. As HPLs are undefined but work for most cell types, chemically-defined media, on the other hand, work only for a specific cell type. To facilitate the search for serum-free media, the database was recently established5. Not for every cell type is yet a serum-free medium available. It will be discussed how a serum-free medium for a specific cell type can be developed6.