Scientists are using human stem cells to create a structure that mimics a pre-embryo and could serve as a research alternative to a real embryo.
They say these “explosives” provide an effective and ethical way to study human development and pursue biomedical discoveries in fertility and contraception.
The latest efforts were detailed Thursday in the journal Nature. The skeletons are not embryos, but scientists nevertheless have not allowed them to develop for the past two weeks out of respect for longstanding ethical guidelines.
A blastocyst is typical of a blastocyst, a ball of cells that forms within a week of fertilization and is about the width of a hair. The models are a “great alternative” to human embryos for research, said Nicholas Revron, a researcher at the Austrian Academy of Sciences and one of the authors of the Nature paper.
“It is very difficult to use human embryos like this to discover any molecules, genes or principles that might allow us to better understand evolution as well as make biomedical discoveries,” said Revron.
But he said additional lab-created positions could be made, altered, and studied in large numbers, and would complement embryonic research.
“This unleashes the potential of scientific and biomedical discovery,” he said. For example, what researchers learn while studying the blastomeres can be used to develop contraceptives that do not contain hormones.
Magdalena Zernicka-Goetz, an expert in stem cell biology at the University of Cambridge, who was not involved in the latest study, noted that this isn’t the first time scientists have made a human blastula. But, she said, “every single step counts,” improving efficiency as researchers try to perfect the model.
Rivron and colleagues used two different types of stem cells to create the blast cells: either embryonic stem cells from pre-established cell lines or stem cells reprogrammed from adult cells, such as skin cells. No new embryonic cell lines were conducted for research.
In the future, stem cells reprogrammed from adult cells are likely to become the new standard in research, he said, but well-established embryonic cell lines are necessary now because they “remain the ultimate reference.” He said the blastocysts were bred separately to be compared alongside the lab-created structures.
The study showed that blastomas reliably replicate key stages of early fetal development. When they were placed in contact with cells from the endometrium that had been stimulated by hormones, about half of them were attached and began to grow in the same way that the blastocysts had.
Riverron said the researchers stopped their growth after 13 days and analyzed the cells. At that point, he said, the set of cells did not reflect a 13-day-old fetus; They weren’t growing enough or regulating either.
Ethical concerns also played a role, he said: For decades, researchers have guided the “14-day rule” about growing embryos in the lab. Earlier this year, the International Society for Stem Cell Research recommended relaxing the rule under limited circumstances.
Riverron, who is part of the working group that has updated the community guidelines, said explosives are not subject to the same rule, but noted that the guidelines state they should never be transferred to an animal or human.
“It is very clear that EOs are not embryos… and if they are not, why apply the fourteen-day rule to these structures?” He said. However, they decided to stop “for the sake of transparency and making sure things are well understood by the public.”
Dr. Barbara Golder, editor-in-chief of The Linacre Quarterly, the journal of the Catholic Medical Association, said the development of explosives shows “how the science is progressing.” But, she said, it is problematic for embryonic cell lines to remain the standard in science.
“Ethical issues will remain as long as there is an association with stem cells derived from aborted fetuses and as long as we have to associate one group of stem cell lines with those derived from fetal stem cells,” she said. .
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