In a new study, scientists have described a promising infertility treatment method that involves turning skin cells into eggs that can produce embryos that are viable.
Infertility
Infertility generally refers to being unable to get pregnant. While infertility can be due to either partner, for women, infertility could be due to hormonal conditions, age, medical conditions, lifestyle factors, and environmental factors.
The condition can also result from problems with the uterus, fallopian tube, ovulation, and egg quality and count. Most infertility cases among women involve issues with ovulation, or the production and release of eggs.
Infertility Treatment
As part of the "Induction of somatic cell haploidy by premature cell division" study, researchers from the Oregon Health & Science University documented IVG (in vitro gametogenesis) within a mouse model. They did so through the initial steps of a technique that depends on transferring a skin cell's nucleus into an egg donation with a removed nucleus.
In mouse models, the researchers coaxed the nucleus of the skin cells into decreasing its chromosomes by 50%. This was so that a sperm cell could fertilize it for the production of a viable embryo.
Shoukhrat Mitalipov, PhD, the study's senior author and the director of the Center for Embryonic Cell and Gene Therapy of the OHSU, shares that the aim is to make egg production possible for those who do not have eggs of their own.
The method could benefit women who have an advanced maternal age or who cannot create viable eggs due to previous cancer treatment or other kinds of causes.
The researchers focused on a method that is based on somatic cell nuclear transfer, wherein the nucleus of a skin cell gets transplanted into a donor egg without a nucleus. This technique was famously used by researchers in 1996 for cloning Dolly the Sheep.
For the OHSU study, the technique's result was described. The method led to embryos with chromosomes from two parents.
Overall, there were three steps involved in the process. First, the mouse skin cell's nucleus was transplanted into the nucleus-less mouse egg. Moving forward and prompted by the donor egg's cytoplasm, the implanted nucleus shreds half of its own chromosomes. Such a process can be likened to meiosis, wherein cells undergo division for the production of mature egg or sperm cells. Then, the new egg is fertilized with sperm through a process known as in vitro fertilization. This leads to the creation of a diploid embryo that has two chromosomal sets. This could ultimately lead to healthy offspring with the same genetic contributions from the two parents.
Previously, the researchers exhibited the proof of concept in a January 2022 study. However, the new study takes things further by performing chromosomal sequencing.
The researchers observed that the nucleus of the skin cell segregated its chromosomes when it was implanted into the egg donor. In certain cases, this took place perfectly, with one from respective pairs of sperm and egg chromosomes that match.
Mitalipov explains that their study shows how they were able to reach haploidy. In the study's next phase, they will be determining how the pairing could be boosted so that the separation of the chromosomal pair can be correctly done.
Paul Amato, MD, professor of gynecology and obstetrics at the School of Medicine at OHSU, notes that while the researchers are also examining the technique in early human embryos and eggs, it may take years before the method could see clinical applications.
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