Scientists Convert Human Skin Cells into Fertilizable Eggs

In a groundbreaking achievement, scientists have successfully transformed human skin cells into fertilizable eggs and fertilized them with sperm in a laboratory setting. This significant advancement, announced on October 25, 2023, holds promise for providing potential solutions for infertility, which affects approximately one in six individuals worldwide.

The team of researchers, led by Paula Amato from the Oregon Health & Science University, cautioned that while this technology, known as in-vitro gametogenesis (IVG), could offer new possibilities for aspiring parents, its practical application is still at least a decade away. The research offers a proof-of-concept that could redefine infertility treatment, potentially enabling older women or those lacking viable eggs to engage in genetic reproduction.

Scientific Breakthroughs and Techniques

Amato emphasized the technology’s potential to benefit same-sex couples as well, allowing them to have children genetically related to both partners. This study, published in the journal Nature Communications, marks a notable progression in reproductive science, differentiating itself from prior research that primarily involved animal subjects.

In recent years, there have been significant strides in this field, including a study from Japan in July 2023, where researchers successfully created mice with two biological fathers. However, the current study is distinct as it utilizes human DNA rather than animal DNA.

To achieve this transformation, the scientists employed a technique known as somatic cell nuclear transfer, which involves transferring the nucleus from skin cells into a donor egg that has had its nucleus removed. This method was famously used to clone Dolly the sheep in 1996. One of the challenges faced in this process is that human skin cells contain 46 chromosomes, while eggs have only 23 chromosomes.

To address this issue, the researchers developed a novel process called “mitomeiosis,” which simulates the natural cell division process to remove the extra chromosomes. They successfully created 82 developing eggs, or oocytes, which were subsequently fertilized using in vitro fertilization (IVF) techniques. After six days, less than nine percent of the embryos had developed to a stage suitable for potential transfer to a uterus, a standard procedure in IVF.

Future Prospects and Challenges

Despite the low success rate, the researchers noted that during natural reproduction, only about one-third of embryos progress to the blastocyst stage, which is necessary for IVF. Amato stated, “The biggest hurdle is trying to achieve genetically normal eggs with the correct number and complement of chromosomes,” highlighting the complexities that remain in this pioneering research.

Ying Cheong, a reproductive medicine researcher at the University of Southampton in the UK, praised the study as an “exciting” breakthrough. She remarked, “For the first time, scientists have shown that DNA from ordinary body cells can be placed into an egg, activated, and made to halve its chromosomes.” Cheong emphasized the potential for this research to transform understandings of infertility and miscarriage and open doors for creating egg- or sperm-like cells for individuals who currently have no other reproductive options.

While other researchers are exploring different techniques, such as reprogramming skin cells into induced pluripotent stem cells, the timeline for widespread application remains uncertain. Amato reiterated, “It’s too early to tell which method will be more successful. Either way, we are still many years away.”

The study adhered to existing U.S. ethical guidelines regulating embryo research, ensuring a responsible approach to this transformative field of science. As this research progresses, it may redefine the landscape of reproductive options available to individuals and couples facing infertility challenges.