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New ethical guidelines needed for human stem cell and embryo research

22 March 2017

The current guidelines relating to embryo research are no longer sufficient. Advances in synthetic biology and stem cell research now enable researchers  to generate tissues with features similar to those of earliest stage human embryos. As these are not embryos, they are not covered by current guidelines. In an article published on 21 March 2017 in the journal eLife, ethicist Jeantine Lunshof from the UMCG and scientists from Harvard Medical School (USA) sketch the outlines for developing new guidelines.

There were several reasons for the team, to review the guidelines for embryo research. The first was an unexpected finding  in the laboratory of the Harvard geneticist George Church,  senior author of the eLife article. Lunshof has been involved with the Church lab in the Department of Genetics at Harvard Medical School since 2006. She also works in the department of Genetics at the UMCG. 

‘A colleague, at a work meeting, described a streak-like feature he saw in tissues he was making from stem cells derived from human skin’ explains Lunshof. ‘He was trying to make neurons (brain cells)  - a goal of many laboratories - but we knew of a published report from another group that indicated that he might be seeing a primitive streak, a feature seen in very early embryos.’

International regulations prohibit the culture of embryos after the primitive streak develops, which is usually after 14 days. The experiment was stopped immediately. In retrospect, the committee for stem cell research oversight (ESCRO) at Harvard University concluded that it could not possibly have been an embryo and was therefore not covered by the embryo guidelines. The experiment did not breach any rules, but further ethical consideration was recommended.

In their article in eLife, the researchers first analyse why the current guidelines (which date from the early 1980s) prohibit researchers from growing embryos for longer than 14 days. This is when the primitive streak usually appears and marks the beginnings of a nervous system. In addition, during the first two weeks, embryos can split to form two identical twins. So until this point, strictly speaking, an embryo cannot be deemed an individual.

‘The problem we have outlined is that current cell and tissue engineering techniques,  based on pluripotent (i.e. not embryo-derived) stem cells can lead to entities that have some features of early embryos, but that do not  follow the regular development process of an embryo..’ The researchers compare the existing regulations with a straight road that ends with a clear ‘STOP’ sign. Research may not proceed any further. ‘But new techniques allow researchers to go ‘off-road’ so that they don't even get to the STOP sign’, as first author John Aach explains.

Therefore, we need to re-set the boundaries, according to the article in eLife. Not general rules based on regular embryonic development, but new guidelines that use new criteria, for example the point when complex brain structures or reproductive cells start to develop. Lunshof: ‘Scientists must provide  input about the characteristics of an embryo – synthetic or not – or an embryo-like structure, that can serve as a basis for new criteria for protection.’ A broad-based community discussion must be established to reach agreement about  the criteria for permitted research. Professional associations, such as the International Society for Stem Cell Research, can then adopt them. ‘This worked well for quite a long time for the 14-day rule that we have now’. According to Lunshof, the new rules are needed because many kinds of embryo-like structures are currently being developed in labs around the world. ‘It’s happening. You can’t rationalize it away. We need to start a broad-based, well-informed dialogue about the ethics of this type of research.’​​​


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