First dedicated guidance for embryo model research published by experts

A code of practice to govern the use of stem-cell based embryo models (SCBEMs) in research has been drafted by an interdisciplinary working group of experts, drawn from institutions across the UK.

The Code of Practice for the Generation and Use of Human Stem Cell-Based Embryo Models – published jointly by Cambridge Reproduction (an interdisciplinary research centre at the University of Cambridge) and PET (the Progress Educational Trust, publisher of BioNews) – is the first comprehensive governance document dedicated exclusively to SCBEMs (see BioNews 1246). These are biological structures grown from stem cells, that can mimic aspects of human embryo development.

'Research involving SCBEMs has enormous potential to improve human knowledge and health, but clearer governance is needed to help researchers work responsibly and maintain public trust,' said Sandy Starr, deputy director of PET and member of the project team that assembled and oversaw the working group. 'The Code sets out core principles for researchers working with SCBEMs, clarifies relevant scientific and ethical considerations, and provides the foundation for a broader system of governance that we will now be working to establish.'

The use of human embryos in scientific research is strictly regulated, including a 14-day limit on culturing embryos in the lab (see BioNews 885, 1152 and 1213). The use of SCBEMs in research is not restricted in this way, and offers additional practical advantages. For example, SCBEMs can be created in large numbers from stem cell lines, whereas human embryos must either be donated to research by patients undergoing IVF (see BioNews 1219) or created from gametes that have themselves been donated for use in research. However, a lack of dedicated oversight – together with the creation of increasingly sophisticated SCBEMs – has led to ethical concerns in recent years (see BioNews 1194).

Drafted by experts in science, law, regulation and ethics, the Code sets out key principles to guide the ethical and responsible use of SCBEMs in research. It emphasises the need to consider what consent is in place, from donors of material from which SCBEMs are created. It also prohibits the transfer of any SCBEM (whether human or nonhuman) to the womb of a human, while prohibiting the transfer of any SCBEM containing human cells to the womb of a nonhuman animal. And the Code proposes the establishment of a dedicated oversight committee to review research involving SCBEMs, assessing the ethical implications of research proposals and ensuring that such proposals are well-justified.

While the Code has been widely welcomed by the scientific and academic community, concerns have been raised regarding the absence of fixed time limits for the culture of SCBEMs. Experts including Professor Søren Holm, a bioethicist at the University of Manchester, argue that this could leave too much discretion to the oversight committee. Professor Holm told Nature News that some would worry the Code 'will not regulate the science, but merely legitimate it'.

The authors of the Code argue that fixed time limits would be impractical, given that different types of SCBEM grow at differing rates and can completely bypass certain developmental stages. Instead, the authors suggest that time limits should be set on a case-by-case basis. Professor Roger Sturmey, of Hull York Medical School and the University of Manchester – who chaired the working group that drafted the code – assured the Guardian that if a proposal involved culturing a SCBEM that closely resembled a post-14-day embryo, then this 'would have to be very well justified'.

Given the rapid pace of advancements in SCBEM research, the authors emphasised the need for the Code to be reviewed regularly, ensuring that it remains relevant and responsive to the latest scientific and ethical developments.