Researchers recommend "a cautious, stepwise approach" to scientific exploration beyond the 14-day limit to study human embryos. In an article published in Science, Insoo Hyun, a bioethics professor at the Case Western Reserve University School of Medicine and the paper's lead author, and colleagues urge policymakers and the International Society for Stem Cell Research (ISSCR) to consider "a cautious, stepwise approach" to scientific exploration beyond the 14-day limit.
‘Researchers should adhere to the 14-day limit, unless a strong scientific justification can be offered to culture human embryos longer where it would be legally permissible to do so.’
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"But first," they write, "one must appreciate the scientific reasons for doing so. Any such proposed research must serve important goals that cannot be adequately met by other means."Read More..
ISSCR is expected to soon release updated guidelines for stem cell and embryo research.
Among the potential benefits of studying human embryos beyond the 14-day limit include understanding how early development disorders originate and developing therapies that address causes of infertility, developmental disorders and failed pregnancy.
Since the first successful birth from in vitro fertilization in the late 1970s, human embryo research has been subject to limits of time and developmental benchmarks.
The general rationale for imposing those limits was that, although considered acceptable to benefit human health and improve reproduction, in vitro research should conclude 14 days after fertilization--about when implantation in the womb is normally completed.
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When this limit was put in place, there were no methods to culture embryos in a dish for anywhere close to two weeks.
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The authors acknowledge that researchers should adhere to the 14-day limit, "unless a strong scientific justification can be offered to culture human embryos longer in locales where it would be legally permissible to do so. Any such proposed research must serve important goals that cannot be adequately met by other means."
Hyun and colleagues propose six principles that can be used to weigh whether research on human embryos can move beyond the 14-day limit, in incremental, measured steps. They note their principles apply for extending the 14-day limit, but also for other complex research.
Among their principles, they emphasize that extended embryo culture should begin in small steps, with frequent interim evaluations. For instance, it would first be necessary to assess feasibility of culture past 14 days, and, if so, to assess whether those newly permitted experiments were informative enough to justify the further use of human embryos.
Their other principles include advocating for research proposals to be peer-reviewed by qualified and independent science and ethics committees; for public dialogue at the local institutional level and, more broadly.
"Realistically," they conclude, "an incremental approach seems to be our only path forward, both from a scientific and a policy standpoint."
Source-Eurekalert