Stem cell researcher:‘We don’t grow people’
A number of international research communities want the in vitro culture of human embryos to be extended beyond 14 days. Until now, this has been an absolute cut-off point.
First published in Norwegian on 13 December 2021.
For several decades, scientists around the world have agreed never to allow the in vitro culture of human embryos to extend beyond two weeks. In several countries, including Norway, the 14-day rule is statutory.
The International Society for Stem Cell Research (ISSCR) draws up ethical guidelines for the field. In May this year, they removed the 14-day rule. No new limit was set. ISSCR believes that those responsible for the ethical approval of such research should decide how long is considered acceptable for the culture of embryos.
The first report on the culture of embryos exceeding 14 days has already been published. In the Nature journal of 17 November, a group of researchers from the UK and Germany shows how they kept an embryo alive until a stage corresponding to 16–19 days post-fertilisation.
The change has sparked debate, and opinions are divided.
ISSCR is an organisation of strong standing. Legislation and regulations vary considerably from country to country, and ISSCR’s influence in ethical issues relating to embryonic research has grown.
‘ISSCR recommendations do not automatically become law in Norway, but the ISSCR gives advice that many people listen to. In countries where there is no statutory provision for the 14-day limit, such as in the United States, it’s likely that the recommendations will lead to changes in how long research can be carried out on embryos’, says Stine Hufthammer Indrelid, senior adviser of the Norwegian Biotechnology Advisory Board.
Almost no research is being conducted in Norway on in vitro human embryos (see the secondary issue). We need to look beyond Norway’s borders to understand what has actually happened.
Will solve ethical problems
Nicolas Rivron is the head of a research group in Austria. In 2018, the group was the first to create a blastoid. They used stem cells taken from mice.
The word ‘blastoid’ relates to ‘blastocyst’, a structure formed in the early embryonic development of mammals. The blastocyst in mice is formed three to four days after fertilisation, compared to four to five days in humans. The suffix ‘oid’ is from Greek and means ‘resembling’. In this case, resembling a blastocyst. We will return to this.
‘The discussions about the 14-day rule do not reflect how the change is part of the solution to the ethical problems in embryonic research’, says Rivron, who works at the Institute of Molecular Biotechnology in the Austrian Academy of Sciences.
In vitro fertilisation
Test-tube baby treatment, or in vitro fertilisation (IVF) as it is called nowadays, began in the 1970s. The treatment was initially controversial. Many found it difficult to accept that scientists and healthcare personnel could manipulate the very germ of human life in Petri dishes.
Despite the birth of Norway’s first test-tube baby in 1983, embryonic research was banned in the country right up until 2008.
The IVF treatment offered by the Norwegian health service had therefore been developed through research in other countries. Today, 4–5 per cent of children in Norway are conceived by IVF.
The 14-day limit was first introduced in the United States in 1979, in a report on IVF from the ethics panel of the US Department of Health. The panel took a positive approach to research on human embryos. One condition was that in vitro embryos should not be kept alive for too long. The panel felt that the limit should be the time an embryo takes to attach itself to the uterus, i.e. 14 days.
Various arguments have subsequently been made, for example that this is the moment of the formation of the so-called primitive streak. For the embryo, this marks the start of the formation of organs, tissues and the central nervous system.
Stem cell research started to grow in importance around the turn of the millennium. Stem cells from embryos became sought-after research objects, and once again a debate was sparked about research on human embryos.
The debate subsided after 2006 when the Japanese researcher Shinya Yamanaka showed how all kinds of cells can be reprogrammed to become embryonic stem cells. Consequently, the need for cells from embryos declined.
The reprogrammed cells, known as iPS cells, gave researchers a unique opportunity to produce different types of human tissue cultures. This has resulted in mini-versions of virtually all human organs, even small brains. The mini-organs, known as organoids, are used to understand how humans and disease develop, and to test medicines and other environmental factors.
Mimics human embryos
This leads us to Rivron’s blastoid. In recent years, several research groups have used iPS cells and embryonic stem cells to grow embryo-like structures named ‘embryoids’ or ‘synthetic embryos’. They are also known as ‘embryo models’, since the idea is to use them in vitro to model the processes that take place in a ‘real’ embryo.
Rivron created the first blastoid, derived from stem cells from mice. Several groups, including Rivron’s, are now working on making blastoids from human stem cells. Rivron’s group is one of six in the world that have reported on trials with such models this year.
Research on human embryos is not permitted in Austria, but embryoids are not regarded as embryos in a legal sense, and are not therefore covered by the ban.
Rivron emphasises that, for the time being, embryo models differ substantially from embryos made in the traditional way, with eggs and sperm. The differences relate to both gene expression and development potential.
‘Embryoids cannot form organisms. We don’t grow people.’
‘Could embryoids have the potential to form organisms in the future, as the models become more and more like embryos?’
‘Maybe. But it could take 50 years. In the meantime, we need to be realistic when we talk about what these structures are.’
Pre-ultrasound stage is key
Rivron believes that the quality of the stem cell-based human embryo models will be the subject of much discussion. Comparing embryos and embryo models could provide answers.
The hope is to fill some of the knowledge gaps about embryo development. The period between the end of the 14 days and the point when the embryo is detectable on ultrasound, i.e. around week 5 or 6, is key to this.
Rivron believes that research on a limited number of embryos for more than 14 days is justifiable because it will reduce the need to use ‘real’ embryos for research.
‘This is how we can solve the ethical challenges linked to embryonic research. Just like the iPS cells, blastoids are an ethical alternative to using human embryos’, he argues.
Anna Smajdor is an associate professor of philosophy at the University of Oslo (UiO) who works with the ethical aspects of embryonic research. She is critical of the fact that the argument for extending the 14-day limit largely relates to solving medical problems, such as preventing miscarriages, pregnancy complications, developmental defects or disease.
‘No one knows if these problems will be solved, as this is basic research’, she underlines.
Smajdor is unsure whether it is a good or a bad idea to remove the 14-day limit, but does not think the desire to remove it is founded on moral conviction.
‘This is a vicarious argument’, she says.
She thinks the argument actually revolves around what researchers have been able to do from a technical perspective. To wit, it is only recently that researchers have been able to keep in vitro embryos alive for more than 14 days.
Smajdor emphasises that the scientific process is not necessarily something that is morally benign.
‘We have a tendency to shape the moral arguments according to the possibilities that exist for further research. But it’s difficult to know beforehand how favourable certain advances in science will be.’
She believes that vigilance is called for in relation to developments.
‘Researchers can fill up their laboratories with an infinite number of embryo-like structures that have been created outside of the usual legal and regulatory processes. This could impact on our ability to treat all human embryos with respect.’
Not scary sci-fi
Rivron has been heavily involved in the discussions behind the changes in the ISSCR guidelines. He feels disheartened that the important research ethics work on the embryo models has been overshadowed by the change to the 14-day rule.
‘The latest version of the guidelines sets out new rules for research on human embryo models. For example, we have established that they should never be implanted in a uterus’, he says.
Rivron also says that the ISSCR has not actually removed the 14-day rule, as it is only an advisory body. The real power lies at the national level.
‘Attitudes to embryonic research are linked to culture. In some places, the embryo is accorded a moral status upon fertilisation, in other cultures this does not happen until a much later stage. By removing the 14-day rule from the guidelines, ISSCR wishes to embrace this variation’, he says.
Rivron is not worried that the development will lead to a loss of respect for the human embryo.
‘We shouldn’t focus on scary science fiction scenarios when we have so much important research to do’, he says.
He is also clear that researchers must take ethics seriously at all times, and be aware of risks.
‘I take this responsibility very seriously. My ultimate nightmare scenario is that legal and regulatory bodies ban this research because they don’t understand it’, says Rivron.
Planning embryoid research
As in other countries, research on embryoids in Norway has progressed at a faster pace than the updating of legislative regulation of embryonic research.
In 2018, the Norwegian Biotechnology Advisory Board called for clarification of the regulations on research into what they referred to as ‘synthetic human entities with embryo-like features’.
‘The law regulates the use of embryonic stem cells and embryos produced by cloning, but it is uncertain whether the law will take account of these new techniques’, says Indrelid of the Norwegian Biotechnology Advisory Board.
Projects of this type are already underway, but have not yet been through the necessary ethical approval process.
‘We are planning to work with blastoids’, says Gareth Sullivan, senior researcher at Oslo University Hospital and researcher at the Institute of Basic Medical Sciences, UiO.
It is uncertain whether Norway will follow the ISSCR and make it possible to extend the 14-day limit. The Norwegian Biotechnology Advisory Board believes that the time is once again ripe to discuss both the benefits and the ethical challenges of research into the creation of life.
Norway can benefit from the knowledge generated by research that keeps embryos alive beyond 14 days. Thus, there are also problematic aspects of maintaining the 14-day rule in this country’, explains Ole Frithjof Norheim from the Board’s magazine GENIalt:
‘It’s a bit of a dilemma for me: Should we take advantage of knowledge and new medical techniques that have been developed through this type of research in other countries, when we ourselves don’t allow such research?’, he asks.
Calls for new limit
Marie Indahl believes that researchers need clear rules. She is the only researcher who regularly handles in vitro human embryos in Norway.
‘It’s an honour to be allowed to conduct research on this precious material’, says Marie Indahl.
Indahl is a researcher and embryologist at Oslo University Hospital (OUS) and a doctoral student at the University of Oslo (UiO).
Every day she collects Petri dishes with fertilised eggs from the clinic at the Department of Reproductive Medicine, OUS. She carefully transports them across the corridor to her research laboratory.
‘On a typical day, I collect 2–3 surplus embryos or eggs’, she says.
Several OUS researchers are involved in the project, but Indahl is responsible for most of the practical aspects of the work.
Over the course of five years, she has collected around 1,000 eggs and 700 embryos at the clinic. She explains that very strict rules and procedures are in place for the donation and handover process.
Donating fertilised eggs
Couples who attend the clinic for in vitro fertilisation (IVF) tend to have some fertilised eggs left over, which they can choose to donate to research. In Norway, only the clinic at OUS offers this option.
Material that is not donated will eventually be destroyed. Indahl almost exclusively receives material that is not of sufficient quality to use in the clinic.
At the lab, she places the fertilised eggs in an incubator, a kind of heated cabinet.
‘I keep them alive up to day 2 or 3 of their development while I study them. Sometimes up to day 6’, she says.
Indahl believes that by enabling embryonic research beyond 14 days, the International Society for Stem Cell Research (ISSCR) may be making the right move.
Clear rules needed
‘If comprehensive ethical assessments are ensured throughout the process, then this change can be good for the research community. The international research work that takes place in the field is so important’, she says.
The change has no practical significance for Indahl herself, since she never reaches anywhere near this limit in her research. The Norwegian legislation also states that research on human embryos must be terminated after 14 days.
‘It might have been nice if the ISSCR had set a new limit. I think researchers need clear rules’, says Indahl.
Her own research entails examining switches that turn genes off and on in the fertilised egg. She has found a marker that seems to be crucial for the embryo doing this in the right way.
‘This could be relevant for infertility’, she says.
The hope is to help identify markers that can tell whether an embryo is viable or not.
‘That’s the dream, but it’s a long way off’, says Indahl.
Translated from Norwegian by Carole Hognestad, Akasie språktjenester AS.