The decision of the ISSCR (International Society for Research with Stem Cells) to eliminate the maximum period of 14 days recommended for research with human embryos in vitro already impacts studies in the area and worries specialists, who fear ethical implications.
The problem is that the institution — made up of experts from 67 countries — has not set a new deadline, raising fears that the manipulation of embryos will go unchecked in nations with looser legislation.
Defined in the 1980s, the term helped to reduce social opposition to the manipulation of embryos and allowed research to advance, says Insoo Hyun, a professor at the Center for Bioethics at the Faculty of Harvard and one of those responsible for the update.
The ISSCR task force says the limit was set when laboratory cultivation did not exceed five days. Now, when it has reached 13, the restriction impedes the advancement of research in a fundamental period of human development, the one in which embryonic cells differentiate into tissues and organs.
The researchers say that with more time to study the embryo, it will be possible to understand the causes of birth defects or frequent miscarriages in the early stages of pregnancy, in addition to boosting regenerative medicine.
For Irene Yan, professor at the Department of Cellular Biology and Development at USP (University of São Paulo), it will also be essential to validate non-embryo-based technologies, such as induced pluripotent cells used in the development of organoids (prototypes of created organs and tissues in the laboratory).
She believes that the scientific community will maintain control over research. “You cannot publish your results unless you demonstrate that the project has passed ethical verification.”
Also looking at the change with optimism is Lygia da Veiga Pereira, a professor of genetics and biology at USP whose group was responsible for the longest seven-day embryo cultivation in the country.
The decision, she says, opens the “black box” of the period between the third week, when in vitro research could no longer be carried out, and the fifth, when it is possible to start ultrasounds of the uterus.
Lygia considers that the ISSCR recommends the use of as few embryos as possible and that the approval of new studies takes into account their relevance.
Other restrictions, however, depend on the legislation of each country. “Spraying the control of the rule can be harmful”, says Eduardo Sequerra, a researcher at the Federal Institute of Brain of Rio Grande do Norte. “What will be the limit for cultivation when, technologically, it is possible to advance?”
The change rekindles the debate over genetic manipulation to, for example, choose sex. “It is a pertinent discussion and should be public. Not everything we have the capacity to do, we must do”, says Sérgio Rego, from Fiocruz’s research integrity committee.
In Brazil, this type of intervention is prohibited. Resolution published this year by the Federal Council of Medicine (CFM) determines: “The techniques of assisted reproduction cannot be applied with the intention of selecting the sex (presence or absence of Y chromosome) or any other biological characteristic of the future child, except for avoid diseases in the possible offspring.”
The advancement of research techniques can also bring ethical dilemmas worthy of science fiction films.
Led by stem cell specialist Jacob Hanna, researchers at the Weizmann Institute of Science in Israel cultivated mouse embryos outside the uterus for up to 11 days (a third of the gestation). Before, the deadline was restricted to 24 hours. Videos show the heart beating in the embryos.
The Israeli has already asked local authorities for permission to work with human embryos for up to 40 days, during which structures such as the heart are already being formed.
“There is a lot to see [a partir do 14º dia], but it is necessary to consider: what are you doing this for and how are you going to use it?”, says Viviane Rosa, a biologist graduated from Unicamp who is part of the group of scientist Marta Shahbazi, at the University of Cambridge. In 2016, Shahbazi reported on the cultivation of embryos until day 13. England still prohibits exceeding the 14-day limit.
In Brazil, the regulation of research with embryos is made by the Biosafety Law, of 2005. Although there is no law that defines maximum cultivation time, a CFM resolution announced after the ISSCR decision determined that embryos for assisted reproduction must not exceed the 14th day of in vitro development.
Brazilian legislation allows donating embryos for research if they are not viable for in vitro fertilization or if they have been frozen until 2005. In both cases, consent from the donor couple is required.
According to the National Embryo Production System, in 2019 the country registered 100,380 frozen embryos, and only 22 were donated for study.
Jorge Venâncio, coordinator of Conep (National Commission for Research Ethics), says that Brazil has little research on embryos.
In 2020 and 2021, Conep approved 68 projects with embryos in the country: 28 correspond to experimental research, when the researcher has control over certain variables, and 26 observational, a type of research in which there is no “intervention” by the researcher in order to to obtain the sample data.
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