Scientists have achieved a significant breakthrough by creating a model human embryo that exhibits a heartbeat and traces of blood. This synthetic structure, developed from human stem cells, provides valuable insights into the initial weeks of life without the need for eggs, sperm, or fertilization. While replicating some cells and structures that typically appear during the third and fourth weeks of pregnancy, the model embryo is incapable of developing into a fetus and lacks the tissues necessary for the placenta and yolk sac formation.
Dr. Jitesh Neupane from the University of Cambridge’s Gurdon Institute clarified that these structures are not actual embryos, but rather models that enable the study of specific aspects of human development. Beating heart cells, which usually emerge on day 23 in a natural embryo, and red blood cells, which appear during the fourth week, were successfully replicated in the model. Dr. Neupane admitted feeling initial apprehension upon witnessing the heartbeat but cautioned against direct comparisons to natural embryos, as the models lack certain features.
The breakthrough involved the use of embryonic stem cells, which are versatile cells derived from human embryos capable of differentiating into any cell type in the body. These cells were guided to grow into an embryo-like structure in the laboratory and then placed in a rotating bottle acting as an artificial uterus. Although the findings are yet to be published, researchers hope they will contribute to a better understanding of recurrent miscarriage causes and the impact of genetic disorders.
Professor Robin Lovell-Badge, head of stem cell biology and developmental genetics at the Francis Crick Institute in London, who was not involved in the study, clarified that these synthetic embryos cannot develop into viable children. This research follows a separate breakthrough reported last week, where scientists created embryos lacking a developing brain or a beating heart but containing cells that would form the placenta and yolk sac.
Sarah Norcross, director of the Progress Educational Trust, a charity assisting individuals facing infertility challenges, emphasized the distinction between these models and actual human embryos. While the model embryos offer valuable insights, it is crucial to recognise their limitations in replicating the complexity of natural human development.
