Human oocytes produced for the first time from donors’ ovarian tissue. A positive step to preserve women’s fertility with cancer
An article has just been published in Molecular Human Reproduction (see HERE) describing the production of human oocytes from ovarian biopsies from ten healthy women. In the study, the authors were able to grow ovarian follicles from the biopsy tissue until their final phase of development; thus, they could theoretically be fertilized by a sperm.
Oocytes from donor ovarian experiments, conducted by scientists in Edinburgh (United Kingdom) and New York (United States), have warranted special attention in several media because, apart from the scientific interest itself, they could be used to preserve the fertility of women who have to undergo chemo or radiotherapy treatment.
Now is not the time to go into the technical aspects of these experiments, which are well detailed in the article in question, although it is interesting to note that the ovarian tissue biopsies were taken with informed consent from women undergoing elective caesarean section. The ovarian tissue pieces thus obtained were cultured in a suitable medium for 8 days, obtaining 87 follicles; after a further 8 days, 54 of the 87 follicles had reached the antral stage of development; and after a further step, 32 complexes containing oocytes >100 µm in diameter were selected. Nine mature oocytes were eventually obtained.
The immature oocytes extracted from the ovarian tissue can be stored in the laboratory for subsequent fertilization. These will be free from contamination by cancer cells, which allows them to be fertilized and to obtain healthy embryos from them for transfer.
There is no doubt that, from a scientific point of view, these experiments constitute an objective medical advance. Nevertheless, as Antonio Requejo, general medical director of the Valencian Institute of Infertility (IVI) adeptly points out (see HERE original article), even though these experiments have already been carried out successfully in mice, in his opinion, it could be several years until the safety of the method is proven and they can be used in humans. This was confirmed by one of the study authors, Richard Anderson, who said that “the culture of these cells is complicated because the structures change a great deal in size since the primordial follicles only measure a few micrometres in diameter while the mature follicles can reach up to 2 cm”.
Produce oocytes from donor ovarian could be a positive step towards preserving the fertility of women — generally young women — who are forced to undergo chemo- or radiotherapy treatments that can cause infertility. As Requejo says, in the same aforementioned report, ovarian tissue can normally be harvested from oncology patients to preserve their fertility, but this practice can involve a risk of reintroducing cancer cells in the woman’s body. With this new technique, the immature oocytes extracted from the ovarian tissue can be stored in the laboratory for subsequent fertilization. These will be free from contamination by cancer cells, which allows them to be fertilized and to obtain healthy embryos from them for transfer.
Read our article about autologous cryopreservation of ovarian tissue
Lights and shadows of this technique
As mentioned, these experiments are an unquestionable medical breakthrough that opens up new prospects in the field of human fertility. In principle, we believe they offer no objective ethical difficulties because the method always uses adult cells obtained from ovarian tissue of adult women, after obtaining their informed consent. Nevertheless, the experiments encourage and open up new possibilities for the use of in vitro fertilization IVF which, as we know, presents ethical difficulties, especially as regards the loss of human embryos.
Photo Embryologist Media
Catholic University of Valencia