Scientists produce 'synthetic' embryos and aim to grow human organs in the lab

A new study conducted by British, American and Israeli scientists has succeeded in producing mouse embryos from stem cells, without the need for fertilization or even a uterus. The fruit of a decade of attempts, the embryos present a heart with beating and brain rudiments, a result that can lead to the cultivation of human organs in the laboratory for transplantation. A preliminary version of the article with the finding was published in the journal Nature, last Thursday (25), bringing again to the debates the ethics in the use of embryonic stem cells.

Scientists believe that an advantage of the technique would be the cloning of the patient’s organs who will receive them, eliminating rejection by the immune system. Founder of Israeli biotechnology company Renewable Bio and one of the authors of the Nature study (as well as leader of another similar study published in the journal Cell ), Jacob Hanna told Sky News Australia that he wants to replicate the results using human cells — including those from his own organism.

Researcher in the Molecular Genetics Department at the Weizmann Institute in Israel, he believes that ethical problems can be resolved if human synthetic embryos lack lungs, hearts or brains. Renewable Bio’s chief executive, Omri Amirav-Drory, said the company does not intend to over-promise or scare.

In addition to the Weizmann Institute, the study was conducted by scientists from the University of Cambridge, UK, and other institutions such as the California Institute of Technology (Caltech). The novelty of developing the fundamentals of the brain is what most excites researchers. “This opens up new possibilities for studying neurodevelopmental mechanisms in an experimental model,” says Magdalena Zernicka-Goetz, professor of biology, biological engineering and mammalian development at Cambridge and Caltech, in whose laboratory the experiment was carried out. “It’s unbelievable that we’ve come this far. This has been our community’s dream for years, and the main focus of our work for a decade, and we finally achieved it”, he celebrates.

The ethical debate

In an interview with the British newspaper The Guardian, Jacob Hanna said that embryoids (which have similarities, but do not bring the full identity of an embryo) cannot develop into complete mice and therefore cannot are “real”. However, as in the case of the creation of a “synthetic” cell a decade ago by the famous American biochemist and entrepreneur Craig Venter, who competed with the American government at the beginning of the years 2000 to sequence the human genome, what is being called “synthetic” is actually still, for the most part, made by nature.

For those who consider that human life already exists in the zygote, the first cell of the organism resulting from fertilization between sperm and egg (an event also called “conception”), reservations like Hanna’s about preventing brain development make no sense. Also because in the watershed study published in Nature the development of the brain in the rodent embryo is one of the main applauded results.

At the beginning of the millennium the debate on the use of embryonic stem cells broke out in the United States. On the one hand, activists such as the now-deceased quadriplegic actor Christopher Reeve saw these polls as a hope for paralyzed people to walk again. The position is correlated with a defense of abortion in the early stages of pregnancy, since many in this group believe that the beginning of the human individual is in the formation of the brain, which would make it permissible to interrupt earlier stages — for research included.

In the journal Bioethics, in 2003, the moral philosopher from the University of Oxford Julian Savulescu makes the granting, for the sake of argument, that the embryo is a person. However, he believes that in some cases “killing him is justified”, and those cases would be the possibility of innocent people benefiting from stem cell research derived from the deaths and the possibility that their chances of survival are greater in a world in which this research is conducted. The philosopher calls this approach “killing to reduce risks”. He thinks that the philosopher John Rawls’s conception of justice, which invites us to think that society would be just under a “veil of ignorance” of what position we would have in it, “endors in some cases killing one person to save another when both would otherwise would die”, he explains.

On the other side of the question is, for example, the Vatican’s Pontifical Academy for Life, which published in the year 2000 a declaration. “The first ethical problem,” says the document, “can be formulated as follows: Is it morally lawful to produce and/or use live human embryos for the preparation of embryonic stem cells? The answer is no.”

Philosophy professor Jason T. Eberl, from the Center for Bioethics at Indiana University, USA, applies it in a book by

principles of philosophy from Thomas Aquinas to bioethics. Eberl shows that the same Thomistic principles are applied with different results by different thinkers. While some Thomists such as Norman Ford and Joseph Donceel argue that before uterine implantation or the formation of the cerebral cortex “a human being does not exist because the embryo has not received a rational soul”, others, such as the American theologian Benedict Ashley, think that the embryo “is a human being, as it only requires a receptive uterine environment to develop into a rational thinking being”. Eberl agrees with Ashley and argues that the rational soul is present from the zygote.

How was the discovery possible?

One reason Zernicka-Goetz and her colleagues are studying the early stages of embryonic development is to understand why some pregnancies end in miscarriage at this time. “The embryonic stem cell model is important because it gives us access to the structure of development at a stage that is normally hidden from us because of the implantation of the small embryo in the mother’s uterus”, explains the scientist. Having access to this structure, scientists can then turn off some genes to see their effect on development and link to known problems. The study already reports some results in this direction.

For the research, the scientists used three types of individual cells to reconstruct the embryos. One type gives rise to the tissues of the mouse organism, and the other types, called extraembryonic stem cells, make two important structures for the embryo’s development: the placenta and the yolk sac, within which it is housed.

The cells were placed in culture medium and spontaneously joined and replicated, forming embryos. The researchers help the process by turning on specific genes that coordinate development. Until then, the result was a rudimentary embryo dubbed a “gastrloid”, with a neural tube (precursor to the nervous system) and the rudiments of the digestive system. This time, the scientists managed to stimulate them beyond that stage, to the point of forming a heart with more complex beats and structures in the direction of brain formation. The product of the study is synthetic embryos similar to natural mouse embryos with eight and a half days of development. When they reach that stage, they stop developing. A goal of the researchers is to extend the development period.

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