Human eggs at maturity in lab

BRITAIN: Human eggs have been grown to maturity outside the body for the first time in a breakthrough for fertility science.

Scientists at the University of Edinburgh announced they had removed egg cells from women’s ovarian tissue and developed them in a laboratory to the point where they were ready to be fertilised.

The advance may one day be used as an alternative to IVF to help older women to conceive. It could also help to preserve the fertility of girls undergoing cancer treatment.

Evelyn Telfer, the senior scientist involved, said the work was the culmination of 30 years of research to better understand the early stages of reproduction. Scientists can now study egg development in the laboratory.

‘‘This is critical as a research tool . . . a window into the developmental aspects of the human ovary,’’ she said. Her work, published in the journal Molecular

Human Reproduction, involved a multistage process of culturing the eggs.

The immature eggs were first taken from women undergoing caesarean sections at Edinburgh Royal Infirmary.

By mimicking the environment inside the human reproductive system, they were then grown from minute ovarian cells to fullsized eggs almost visible to the naked eye.

Although the intention was to understand the processes involved better, one of the obvious applications of the technology would be in girls with cancer.

‘‘At the moment, prepubertal girls come to the clinic with bloodborne cancers that require damaging chemotherapy,’’ Telfer said.

This can kill or seriously damage existing eggs. The only option at present is to remove healthy ovarian tissue and then reimplant it after they have been cured, but this risks reintroducing cancer.

Instead, if this new process is perfected, eggs could be taken, matured and stored to be used later. There is also a possibility that it could one day be incorporated into fertility treatment.

‘‘There’s no reason why we couldn’t use it in older women as an alternative to IVF, avoiding the use of hormones and multiple cycles,’’ Telfer said.

Unlike with IVF, couples could take many more eggs and develop them at the same time before choosing the ones that look most promising.

Marco Gaudoin, medical director of the Scottish fertility clinic GCRM, was excited by this prospect.

‘‘The potential of this is enormous. You are still going to have these cells in the ovary even when you are approaching the menopause. If these cells grow reliably [in the laboratory] then you have got a better chance of having a child which is genetically your own.’’

The technology remains in its early stages and there are some abnormalities in the eggs. Because they cannot be fertilised without a licence, it is not possible to tell how significant these defects are. The process is also highly inefficient. Nine mature eggs were grown from 48 that were cultured.

Telfer said scientists needed to investigate the eggs more closely. ‘‘The importance for us is to emphasise that while this is a significant advance, there is lots of work to do. Our priority is to show if these are normal or not.’’

Robin Lovell-Badge, from the Francis Crick Institute in London, said that if it were to be developed clinically as an option for girls having cancer treatment it would also have to be tested on prepubertal ovaries.

‘‘While this work may contain an important step, many more will have to be taken to reach the destination. But you can’t make an omelette without breaking eggs.’’

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