Scientists announced on Wednesday that they have successfully transformed human skin cells into eggs and fertilized them with sperm in the lab for the first time. This breakthrough holds the potential to enable infertile individuals to have children in the future.
The technology is still several years away from being available to prospective parents, as cautioned by the US-led team of scientists.
However, external experts have noted that this proof-of-concept research could eventually redefine infertility, a condition affecting one in six people globally.
If successful, the technology known as in-vitro gametogenesis (IVG) could allow older women or women lacking eggs for other reasons to genetically reproduce, according to Paula Amato, co-author of a new study announcing this achievement.
“It could also enable same-sex couples to have a child genetically related to both partners,” said Amato, a researcher at the Oregon Health & Science University in the United States.
Significant progress has been made in this field in recent years, with Japanese researchers announcing in July that they had created mice with two biological fathers.
However, the new study, published in the journal Nature Communications, marks a significant advance by using human DNA instead of mouse DNA.
The scientists initially removed the nucleus from normal skin cells and transferred them into a donor egg that had its nucleus removed. This technique, known as somatic cell nuclear transfer, was previously used to clone Dolly the sheep in 1996.
Nonetheless, a challenge remained: skin cells have 46 chromosomes, whereas eggs have 23.
The scientists managed to remove these extra chromosomes using a process they termed “mitomeiosis,” which mimics the natural cell division process.
They created 82 developing eggs, called oocytes, which were then fertilized by sperm through in vitro fertilization (IVF).
After six days, less than nine percent of the embryos developed to the point where they could hypothetically be transferred to the uterus for a standard IVF process.
However, the embryos exhibited various abnormalities, leading to the termination of the experiment.
While the nine-percent rate was low, the researchers pointed out that during natural reproduction, only about a third of embryos reach the IVF-ready “blastocyst” stage.
Amato estimated that the technology is at least a decade away from becoming widely available.
“The biggest hurdle is achieving genetically normal eggs with the correct number and complement of chromosomes,” she said.
– Breakthrough –
Ying Cheong, a reproductive medicine researcher at the UK’s University of Southampton, praised the “exciting” breakthrough.
“For the first time, scientists have demonstrated that DNA from ordinary body cells can be placed into an egg, activated, and made to halve its chromosomes, mimicking the special steps that normally create eggs and sperm,” she said.
“While this is still very early laboratory work, in the future, it could transform how we understand infertility and miscarriage, and perhaps one day open the door to creating egg- or sperm-like cells for those who have no other options.”
Other researchers working to create lab-generated eggs are employing a different technique. This involves reprogramming skin cells into what are known as induced pluripotent stem cells, which have the potential to develop into any cell in the body, then transforming these into eggs.
“It’s too early to determine which method will be more successful,” Amato said. “Either way, we are still many years away.”
The researchers adhered to existing US ethical guidelines regulating the use of embryos, as stated in the study.
