April 15, 2021

A Spanish center collaborates in Greece in a gestation of three 'parents' | Society

A Spanish center collaborates in Greece in a gestation of three 'parents' | Society

A 32-year-old woman from Greece is in the 28th week of gestation after undergoing a process to generate what is informally called a son of three genetic parents (which has genes of three people) with the participation of the Embryotools clinic, from Barcelona. This technique consists in that the genetic material of the nucleus of a woman's ovum (it can be done by extracting the whole nucleus or, as in this case, the chromosomes when they are placed in a row during the process of division of the gamete) is transferred to another ovule devoid of its nucleus, and then fertilized. In this way, the resulting embryo will have genetic material from three sources (hence that of three parents): that of the nucleus of a woman's egg -the donor-, that of the sperm and a small faction that is in the mitochondria of the ovule of the recipient woman, an organelle of the cellular cytoplasm that has a key role in the energy cycle of the cells and whose DNA is assumed to be the heir of an ancient bacterium that fused with another to create the eukaryotic cell from which most of the cells are made current living beings. The system was developed to have children who do not inherit the alterations in the genome of the mother's mitochondria. It has already been used for this purpose in Mexico and UK, for example.

But in this case is not to avoid an illness linked to mitochondrial DNA, but to facilitate the fertilization of an ovule virtually identical genetically to the pregnant woman, who has a low ovarian response, had already gone through two interventions derived from an endometriosis ( an inflammation of tissues of the female genital area that hinders processes such as implantation of the fertilized ovum) and that had undergone four cycles of fertilization in vitro without achieving any pregnancy. The clinic states that there are 24 other women waiting to undergo the same technique, and that in eight cases the embryos are already created.

"However, we must be cautious, it can not be incorporated into the routine of any assisted reproduction clinic overnight, it requires special technology and extensive training of researchers with a long learning curve," says Gloria. Calderón, co-founder and director of Embryotools.

Nuno Costa-Borges, of the company, highlights that the process has come after extensive experimentation in mice, made in Spain, presented at the congresses of the American specialty society in recent years, and that has been done in Greece for their collaboration with the Institute of Life in Athens, which they helped to found.

In its note, the company informs that in Spain the law does not allow, in theory, this technique, although it leaves open the possibility that the National Commission of Assisted Human Reproduction authorizes it, but it has not done it. Almost at the same time that it has been known about the trial of Greece, the Margen de Granada clinic received the negative to try the same in Spain. It was tried in 5 or 10 cases a year of couples with "three or more unexplained failures of fertilization in vitro in young women, with a normal sperm and no obvious endocrine or immunological problem, "the company explains in a note." The unusable ovules would be used to find the cause of the ooplasm problem. [lo que queda del óvulo cuando se le quita el núcleo celular] and understand "why you could not get pregnant," he adds.

The Ministry of Health explains in a note addressed to the Granada center that "this procedure can be considered an experimental technique that is not contemplated in Spanish legislation, and as such its application requires authorization from the corresponding health authority [autonómica], after a favorable report from the National Commission of Assisted Human Reproduction. "But this does not come, for two reasons: First, that Spanish law prohibits the use of" gametes used in research or experimentation can not be used for transfer to women or to originate pre-embryos for the purpose of procreation ". And, the second, that the law expressly sanctions the implantation of embryos "originated with oocytes from different women" and the "practice of nuclear transfer techniques for reproductive purposes".

These qualifications were introduced in the law, whose last modification was in 2006. The list of permitted practices (minus cloning) was then deleted from the draft in the expectation that scientific advances could render it obsolete, but an annex was established with them, which can be modified at the direction of the National Commission on Assisted Human Reproduction, which is which has rejected the request of the Granada clinic founded by Jan Tesarik and Carmen Mendoza.

Irene Cuevas, of the board of directors of the Spanish Fertility Society, supports the use of this technique to avoid diseases due to mitochondria, but affirms that its use to improve fertility "has alternatives" and is "an experimental technique". "We do not know if the child that is born will have epigenetic alterations [en los marcadores que determinan la expresión de los genes] because the manipulation, which in the media seems simple, is not and requires a lot of expertise ".


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