Scientists Create 'Human Embryo Model' Without Sperm Or Egg

A team of scientists at the Weizmann Institute have successfully created an 'embryo model' that closely resembles a 14-day-old human embryo, without using sperm, eggs or womb.

The team of scientists said that they created the models of human embryos from stell cells cultured in the lab. That's not all, it even released hormones that turned a pregnancy test positive.

This research marks a significant milestone in the field of embryo modelling. This will offer an ethical way of understanding the earliest moments of our lives.

The team of scientists said that these synthetic embryo models had all the structures and compartments characteristic of this stage, including the placenta, yolk sac, chorionic sac and other external tissues that ensure the models' dynamic and adequate growth.

"The drama is in the first month, the remaining eight months of pregnancy are mainly lots of growth," Professor Jacob Hanna says. "But that first month is still largely a black box. Our stem cell-derived human embryo model offers an ethical and accessible way of peering into this box. It closely mimics the development of a real human embryo, particularly the emergence of its exquisitely fine architecture."

The research has been published in Nature.

"This is really a textbook image of a human day-14 embryo," Prof Hanna says, which "hasn't been done before".

The researchers said that instead of a sperm and egg, the starting material was naive stem cells which were programmed to gain the potential to become any type of tissue in the body, BBC reported. 

4 types of cells were found in the earliest stages of human embryos, including:

• epiblast cells, which become the embryo proper (or foetus)
• trophoblast cells, which become the placenta
• hypoblast cells, which become the supportive yolk sac
• extraembryonic mesoderm cells

The scientists mixed a total of 120 of these cells in a precise ratio and then waited for the results. Approximately 1 per cent of them self-assembled into a structure. But this does not resemble a human embryo.

"I give great credit to the cells - you have to bring the right mix and have the right environment and it just takes off," Prof Hanna says. "That's an amazing phenomenon."

Researchers believe that these embryos hold the potential to shed light on various aspects of early development. This can also contribute to improving in vitro fertilization (IVF) success rates and testing the safety of medicines during pregnancy.