Proof of Concept Achieved for Generating Eggs from Somatic Cells
- 20 oct
- 2 Min. de lectura
Researchers at Oregon Health & Science University (OHSU) have accomplished a unique scientific milestone, achieving proof of concept for generating eggs from somatic cells—specifically, skin cells—that were capable of producing early human embryos. This research, published in the journal Nature Communications, introduces a potential avenue for in vitro gametogenesis (IVG).
The technique promises hope for millions of people facing infertility due to the lack of viable eggs, such as women of advanced maternal age or those whose egg production capacity was harmed by prior cancer treatment. Furthermore, it presents the theoretical possibility for same-sex couples to have children genetically related to both partners.
The methodology, characterized by senior author Shoukhrat Mitalipov, Ph.D., as "mitomeiosis," represents what he calls a "third" method of cell division, distinct from mitosis and traditional meiosis. Instead of building eggs from scratch using stem cells, the OHSU team employed a strategy based on somatic cell nuclear transfer (SCNT), the same technique used in 1997 to clone Dolly the sheep.
In this process, the nucleus of a skin cell (which contains 46 chromosomes) is transplanted into a donor egg stripped of its own nucleus. The crucial step is the induction of "mitomeiosis," which prompts the implanted nucleus to discard half of its chromosomes, yielding a haploid egg with 23 chromosomes. When this new egg is subsequently fertilized with sperm through standard IVF procedures, it results in a diploid embryo carrying genetic material from both parents.
The researchers reported producing 82 functional oocytes that were fertilized. However, the technology is currently fraught with challenges. Most of the fertilized eggs failed to progress beyond the 4- to 8-cell stage, and only a small percentage—9%—developed to the blastocyst stage six days after fertilization.
A significant limitation identified by the team is the high prevalence of chromosomal abnormalities, known as aneuploidy, which prevents the resulting embryos from developing normally. Additionally, unlike in natural meiosis, the induced mitomeiosis resulted in random distributions of chromosomes and failed to achieve the necessary recombination (swapping parts) between chromosome pairs. Amander Clark, a developmental biologist, stated that because all resulting embryos had abnormal chromosome numbers, the technology "should not move into clinical practice for reproductive purposes" at this stage.
Researchers, including first author Nuria Marti Gutierrez, Ph.D., acknowledge that much work remains, specifically needing to understand how to ensure chromosomes pair and separate faithfully. Mitalipov’s team remains optimistic, but cautions that this development is strictly a proof of concept. They estimate that it will require at least a decade of further research before the approach could be deemed safe and effective enough to advance to a clinical trial.
🔖 Sources
