Human embryos grown sans sperm or egg spark debate

AFP , Sunday 10 Sep 2023

A groundbreaking achievement has been accomplished by scientists in Israel, as they have successfully engineered a replica of a human embryo within a laboratory setting using stem cells, without relying on traditional components like sperm, eggs, or a womb.



This remarkable feat offers a unique opportunity to gain insights into the early phases of embryonic development, providing a glimpse into the intricate processes at play.

The team from Israel's esteemed Weizmann Institute of Science has managed to create a model that strikingly resembles an embryo at day 14, a crucial stage where internal structures begin to form, setting the groundwork for the subsequent development of body organs. By simulating this pivotal juncture in embryogenesis, the researchers are shedding new light on the complex mechanisms that underlie the earliest stages of human life.

This groundbreaking work has been published in the renowned journal Nature, following a pre-print release during the International Society for Stem Cell Research (ISSCR)'s annual meeting in Boston in June. The Israeli team, led by Jacob Hanna, emphasized that they are still far from being able to create an embryo from scratch.

The question of when an embryo model can be considered an actual embryo is pivotal, as it determines the regulatory framework that governs such research. Hanna states, "At the moment we are really, really far off from that point." However, this work holds the potential to revolutionize various aspects of medical research. It could pave the way for innovative methods to test the effects of drugs on pregnancies, enhance our understanding of miscarriages and genetic diseases, and even facilitate the growth of transplant tissues and organs.

Hanna acknowledges that while the model is not identical to a human embryo, it represents a significant milestone. He explains that his team utilized stem cells derived from adult human skin cells, as well as other cells cultured in the lab, and reverted them to an early state with the capacity to differentiate into various cell types. Through careful manipulation, they established a structural foundation that resembles an embryo. It is vital to note that this model is not an actual or synthetic embryo, a term criticized by the ISSCR and other scientists. Rather, it serves as a tool to demonstrate the workings of an embryo.

Hanna elaborates, stating that in approximately 1 percent of the aggregates created, the cells begin to differentiate correctly, migrate, and sort themselves into the appropriate structures. The team's progress has allowed them to reach the equivalent of day 14 of human embryo development. Moving forward, their objective is to advance to day 21 and achieve a success rate of 50 percent.

Magdalena Żernicka-Goetz, a professor of development and stem cells at the University of Cambridge, acknowledges the significance of this study. She highlights that several similar human embryo-like models have been published worldwide this year, including ones from her own laboratory. While none of these models fully replicate natural human development, each contributes to the experimental study of various aspects of human development.

The study raises ethical questions regarding the potential for future manipulation of human embryo development. Hanna and others acknowledge these concerns. However, he draws a comparison to nuclear physics, suggesting that research in that field should not be halted simply because of the possibility of someone creating a nuclear bomb. It is crucial to engage and fully inform the public, ensuring transparency and avoiding any secretive endeavors.

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