Shocking: Scientists grow whole model of human embryo, without sperm or egg

 

Scientists have successfully grown a structure that closely resembles an early human embryo, all without using sperm, eggs, or a womb. The innovative "embryo model" created by the Weizmann Institute team is generated from stem cells and remarkably mimics the appearance of a 14-day-old human embryo.

Notably, this embryo model also demonstrated functionality by releasing hormones that triggered a positive result on a pregnancy test in the laboratory. The primary goal of creating embryo models is to offer an ethical means of studying the earliest stages of human life.

The first few weeks following fertilization are a period of rapid transformation, yet it remains poorly understood and is a significant source of miscarriages and birth defects. Professor Jacob Hanna from the Weizmann Institute of Science emphasizes the limited knowledge in this area, describing it as a "black box."

This research, published in the journal Nature, marks a breakthrough as the Israeli team claims to have created the first "complete" embryo model that replicates all key structures found in early embryos. Instead of using sperm and eggs, the researchers began with naive stem cells, which were reprogrammed to possess the potential to develop into any type of tissue.

Chemicals were then employed to guide these stem cells into becoming four types of cells present in early human embryos. These cells include epiblast cells (which form the embryo), trophoblast cells (which develop into the placenta), hypoblast cells (supportive yolk sac), and extraembryonic mesoderm cells.

Mixing 120 of these cells in precise ratios allowed the scientists to observe a fascinating phenomenon. About 1% of the cell mixture spontaneously assembled itself into a structure resembling a human embryo, albeit not identical. The researchers marveled at the cells' ability to self-organize and emphasized that this process was remarkable.

The embryo models were permitted to develop until they resembled embryos at the 14-day post-fertilization stage, which is often considered the legal limit for standard embryo research in many countries.

The potential applications of these embryo models are promising. They can provide insights into how different cell types emerge, observe the initial stages of organ development, and gain a better understanding of inherited or genetic diseases. Additionally, there is potential to improve in vitro fertilization (IVF) success rates by identifying why some embryos fail to develop or by testing the safety of medications during pregnancy using these models.

Despite the promising progress, there is room for improvement, as the current 99% failure rate of the model assembly presents challenges for understanding miscarriages or infertility. Furthermore, the closer these models come to resembling actual embryos, the more ethical questions they raise regarding their regulation and usage.

In conclusion, this research represents a significant advancement in the field of embryology and offers a potential avenue for deeper insights into early human development. However, it also raises important ethical and regulatory considerations as science continues to push boundaries in understanding the mysteries of life's beginnings.