Scientists create the world’s first ‘synthetic embryos’
For a new life to enter this world, three things have been required since time immemorial: sperm, an egg, and a womb to carry the fertilised egg until birth. Breakthrough research at the Weizmann Institute of Science in Rehovot has shown that life can be created without the presence of these primordial three. There, scientists made a mouse embryo without an egg, sperm, or womb.
About The Discovery
Scientists at Israel’s Weizmann Institute discovered that stem cells from mice could be coaxed into self-assembling structures with an intestinal tract, the beginnings of a brain, and a beating heart. The living structures, known as synthetic embryos because they are created without fertilised eggs, are expected to drive a deeper understanding of how organs and tissues form during the development of natural embryos in the near future.
However, researchers believe the work could reduce animal testing and pave the way for new sources of cells and tissues for human transplantation. For example, skin cells from a leukaemia patient could potentially be transformed into bone marrow stem cells to treat their condition.
Prof Jacob Hanna, who led the effort said“Remarkably, we show that embryonic stem cells generate whole synthetic embryos, meaning this includes the placenta and yolk sac surrounding the embryo.”
About The Mouse Model
For eight days, mouse stem cells, which can develop into any organ or tissue, were grown in an artificial womb, where they developed a rudimentary brain, an intestinal tract, and a beating heart. The embryo stopped growing after eight days, which is equivalent to three months of pregnancy in a mouse.
The team used a mechanical womb to allow natural mouse embryos to grow outside the uterus for several days in order to nurture mouse stem cells for more than a week, nearly half the gestation time for a mouse. Some of the cells were pre-treated with chemicals, which activated genetic programmes that caused them to develop into placentas or yolk sacs, while others developed naturally into organs and other tissues.
While most of the stem cells failed to form embryo-like structures, about 0.5 per cent formed small balls that developed distinct tissues and organs. When compared to natural mouse embryos, the synthetic embryos were 95 per cent identical in terms of internal structure and cell genetic profiles. According to the scientists, the organs that formed were functional.
The researchers are now trying to figure out how stem cells know what to do and how they self-assemble into organs and find their way to their designated locations inside an embryo. Liked this post? Don’t forget to check out our other short stories in our Quick Read section.