Researchers at the University of Edinburgh, Scotland have grown human eggs from their earliest stages to maturity in a laboratory for the very first time.
This had previously been achieved with mouse egg cells, while human eggs had been successfully cultivated starting from a much later stage of development.
This is the first time the process of egg cell (oocyte) maturation, which normally takes place in an ovary, has been done in a lab.
Immature eggs, contained in “follicle” cells which line the ovary, were removed from healthy volunteers and developed in the lab to a point where they could be fertilized with a sperm.
Professor Evelyn Telfer, of the School of Biological Sciences, who led the research, said: “Being able to fully develop human eggs in the lab could widen the scope of available fertility treatments.”
We are now working on optimizing the conditions that support egg development in this way and studying how healthy they are. We also hope to find out, subject to regulatory approval, whether they can be fertilized, said Telfer.
The study has also given insight into how human eggs develop at various stages, which could aid research into other infertility treatments and regenerative medicine.
The process is very tightly controlled and timed in the human body, some eggs will mature during the teenage years, others more than two decades later.
An egg needs to lose half its genetic material during development, otherwise there would be too much DNA when it was fertilized by a sperm.
This excess is cast off into a miniature cell called a polar body, but in the study the polar bodies were abnormally large.
“This is a concern,” Prof Telfer said. But it is one she thinks can be addressed by improving the technology.
Women who can’t ovulate naturally, young cancer patients and potentially even post-menopausal women could benefit if fertility ‘breakthrough’ proves safe.
The next step is to fertilize one of the lab-made eggs to create an embryo for further research. The study was published in the journal Molecular Human Reproduction.