A team of scientist has created fertilized egg -like cells using ordinary skin cells. The discovery may represent a major advance in the investigation of infertility.
Using a technique recently developed to remove excess chromosomes, a team led by the clinical biologist Nuria Marti-Gutierrezfrom the University of Health and Science of Oregon (OHSU), created Human ovules that can be successfully fertilized and start developing as zygotes.
The results of the were presented in an article published this Thursday in Nature Communications.
According to the authors of the study, the discovery is a proof of concept which may offer hope for future infertility cases, but we will still be at least 10 to 15 years away from a clinical application of this technique
“We can take advantage of the mature oocyte’s cellular machinery to essentially reprogram a somatic cellinstead of relying on months of cellular culture to produce induced pluripotent stem cells, ”he told Gynecologist-Obstrette and reproductive endocrinologist Paula Amatoohsu researcher and corresponding author of the study.
“Theoretically saves time and potentially results in fewer genetic and epigenetic aberrations,” adds the researcher.
A Infertility affects millions of people around the world. It is officially defined as a inability to achieve a successful pregnancy After 12 months of attempts, and there may be numerous contributory causes.
Among these causes are Gametes that do not work adequatelyand whether sperm, eggs, or a combination of both.
There may be many reasons why eggs do not workfrom diseases such as cancer to decline related to age in the quantity and quality of oocytes – cells that become eggs.
A possible treatment involves a technique called gametogénese in vitro (GIV), which consists of produce gametes using their own genetic material of the patient. This was achieved in mice, but not in humans.
A Nuclear transfer of somatic cells (TNCs) is a GIV form in which the nucleus of an egg cell is replaced by the nucleus of a somatic, or body cell. However, it has significant challenges.
One of these challenges is the extra chromosomes. A normal gamet contains a set of 23 chromosomes, half the number found in most body cells. A GAMETA created with TNCs has 46.
To solve this problem, the researchers developed a technique they call Mitomeiosean artificial method that mimics the natural process of cell division.
In this technique, “the core containing the DNA of a skin cell of the intended progenitor is tRansfound to an oocyte donor (egg) to which the core was removed, ”explains Amato.
“This rebuilt egg is then extruding half of its chromosomal complement to achieve haploidia (23 chromosomes). This is the process we are calling mitomeiosis, ”says the researcher.
“The now haploid egg is then fertilized with sperm from the other intended parent, resulting in a diploid zygote (embryo)hopefully with a normal number of chromosomes (46 – half of each parent), ”adds Amato.
Using this technique, the researchers created 82 functional oocytes Using eggs and damn skin, and then used the sperm of donor to fertilize the oocytes.
The results were mixed. Most oocytes have stopped developing in the 4 to 10 cell division phase. About 9% continued to develop in a blastocyst- a relatively low rate, but a successful first demonstration that The technique can work.
The experience was finished on the sixth day Development, because it is at this point that a developing blastocyst is usually implanted in a patient.
The blastocysts showed signs of chromosomal anomaliesbecause the ejection of additional chromosomal material during mitomeiosis was random. This presents the next challenge to be addressed.
“Unless the embryo contains a normal number of chromosomes, that is, one of each of the 23 pairs, the embryo will not normally develop And it will not result in a healthy baby, ”explains Amato.“ We are now working on ways to improve pairing and chromosomal segregation to result in a normal complement of chromosomes in the resulting embryos. ”
Refining the technique will probably take at least a decadewarns Amato. But it is a success that demonstrates the viability of mitomeiosiswhile tracing a clear path to future investigation.
