What does the term “xeno-free” mean?
The utility of stem cells in therapeutic applications for regenerative medicine has caused a movement within the scientific community for a more a defined cell culture system. Pluripotent stem cells and other clinically relevant stem cell types all have unique needs in order to proliferate and perform as they would in vivo. Finding suitable cell culture conditions that not only promote proliferation, but also maintain stem cell properties is a difficult task when it seems that the most optimal conditions rely on undefined biological substances and factors derived from serum, feeder cells, growth factors, and other supplements. Today there are a lot of companies that have responded to the market need for ‘defined’ media and package their products as part of a ‘defined’ cell culture system.
With this shift, new labels, such as xeno-free, have become increasing popular as a marketing tool for new product lines. However, what does ‘xeno-free’ really mean? Researching the literature and technical reports provided by many life science research companies implies that the term xeno–free is defined differently depending on the source. It is my understanding that xeno-free is defined as all components (i.e. in the cell culture medium) are derived from the same organism whether it is animal (e.g. bovine) or human. However, if you look closely at several of the defined, xeno-free cell culture media, some do contain human blood derived components and even animal-derived components.
Researchers hoping to develop stem Cell Therapy treatments need to meet the regulatory guidelines and have a cost-effective system that is compatible with their end use. It seems clear that for therapeutic applications, the ideal cell culture medium should be devoid of any animal and/or human derived components, should provide equal or increased performance (e.g. cell proliferation, protein production, etc.) over serum, and would be cost-effective.
Based on the conflicting uses and views of the term ‘xeno-free’, it should be redefined or we should introduce a new label that confers it is a human- and animal-free product. The development and production of human recombinant proteins that are essentially ‘blood-free’ can help to create a defined cell culture media as well as provide consistency and perhaps higher productivity. These products could help us reach our goal of the ideal stem cell media – devoid of any animal or human derived components.
If you are interested in this topic, please see our more recent publications on the topic, “Xeno-free, What Is It?” and “What does Xeno-Free really mean, and why does it matter to cell culture scientists today?“