NEW HOPE FOR INFERTILITY
For the First time scientists have Fully developed human eggs in laboratory
Scientists have succeeded for the first time in growing human eggs in a laboratory from the earliest stages in ovarian tissue all the way to full maturity - a scientific step that had previously been taken in mice.
Publishing their result in the journal Molecular Human Reproduction on Friday, scientists from Britain and the United States said it could one day help in developing regenerative medicine therapies and new infertility treatments.
In previous studies, scientists had developed mouse eggs in a laboratory to the stage where they produced live offspring, and had also matured human eggs from a relatively late stage of development.
This latest work, by scientists at two research hospitals in Edinburgh and the Center for Human Reproduction in New York, is the first time human eggs have been developed outside the human body from their earliest stage to full maturity.
Prof Evelyn Telfer, one of the researchers, told the BBC: “It’s very exciting to obtain proof of principle that it’s possible to reach this stage in human tissue.
“But that has to be tempered by the whole lot of work needed to improve the culture conditions and test the quality of the oocytes [eggs].
“But apart from any clinical applications, this is a big breakthrough in improving understanding of human egg development.”
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.
“Being able to fully develop human eggs in the lab could widen the scope of available fertility treatments. We are now working on optimising the conditions that support egg development in this way and studying how healthy they are,” said Evelyn Telfer, who co-led the work.
Independent experts not directly involved in this work praised it as important, but also cautioned that there is much more to do before lab-grown human eggs could be safely be made ready for fertilisation with sperm.
“This early data suggests this may well be feasible in the future,” said Ali Abbara, a senior clinical lecturer in Endocrinology at Imperial College London.
“(But) the technology remains at an early stage, and much more work is needed to make sure that the technique is safe and optimised before we ascertain whether these eggs remain normal during the process, and can be fertilised to form embryos that could lead to healthy babies.”
Darren Griffin, a genetics professor at Kent University in the UK, said the work was “an impressive technical achievement”.
If success and safety rates were improved, he said, it could in future help cancer patients wishing to preserve their fertility while undergoing chemotherapy treatment, improve fertility treatments, and deepen scientific understanding of the biology of the earliest stages of human life.
An egg needs to lose half its genetic material during development, otherwise there would be too much DNA when it was fertilised by a sperm, says a report in BBC online.
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,” said Prof Telfer. But it is one she thinks can be addressed by improving the technology.
Work on mouse eggs, which was nailed 20 years ago, showed the technology could be used to produce live animals.
Matching this achievement in human tissue could eventually be used to help children having cancer treatment. Chemotherapy and radiotherapy risks making you sterile.
Women can freeze matured eggs, or even embryos if they are fertilised with a partner’s sperm, before starting treatment.
This is not possible for girls with childhood cancers.
At the moment they can have ovarian tissue frozen before treatment, which is then put back in to mature years later if the patient wants children of their own.
But if there are any abnormalities in the frozen sample then doctors will think it is too risky. Being able to make eggs in the lab would be a safer option for those patients.
Mr Stuart Lavery, a consultant gynaecologist at Hammersmith Hospital, said: “This work represents a genuine step forward in our understanding.
“Although still in small numbers and requiring optimisation, this preliminary work offers hope for patients.”
It would be legal to fertilise one of the lab-made eggs to create an embryo for research purposes in the UK.
But the team in Edinburgh do not have a licence to carry out the experiment. They are discussing whether to apply to the embryo authority for one, or collaborate with a centre that already has one.
The technology remains at an early stage, and much more work is needed to make sure that the technique is safe …” Ali Abbara, Clinical lecturer
This is an elegant piece of work, demonstrating for the first time that human eggs can be grown to maturity in a laboratory Channa Jayasena, Imperial College London
This work represents a genuine step forward in our understanding. This preliminary work offers hope for patients Stuart Lavery, Consultant gynaecologist
Molecular characterisation and chromosomal analysis is needed to show how these cells compare with normal eggs Prof. Azim Surani, Director of germline research
Significant further research is now needed to confirm that these eggs are healthy and functioning as they should do Prof Helen Picton, Expert in reproduction
it’s very exciting ... that it’s possible to reach this stage in human tissue..., this is a big breakthrough in improving understanding of human egg development 20 years ago the work on mouse eggs showed the technology could be used to produce live animals