(China Daily)
Updated: 2008-04-22 07:06

Scientists have found a way to store and grow a woman's immature eggs in the laboratory using a technique which could be used to protect the fertility of women undergoing chemotherapy.

Anti-cancer drugs can often destroy the ovary's follicles, where immature eggs remain dormant from birth until they are matured by the body.

This means a woman may survive cancer but become infertile as a result.

Several centers in the UK already offer to store pieces of ovary tissue from women about to undergo cancer treatment in the hope that, one day, techniques can be found to mature the eggs and use them for IVF.

The new research, led by Evelyn Telfer of the University of Edinburgh, has taken a major step towards that goal. She took pieces of ovary tissue and, by adding artificial growth hormones in the laboratory, successfully grew the eggs within the follicles to an advanced stage.

The ovary tissue she used was donated by six women who gave birth by elective caesarean section, and about a third of the follicles within them went on to reach the advanced stage of development. Eventually, said Tefler, fully matured eggs using this technique could be used in assisted reproduction procedures such as IVF.

The results are described today in the journal Human Reproduction.

Telfer said the new technique had several advantages over standard practices.

It took just 10 days for an egg to mature using the new method, while it might take several months for an egg to mature inside the ovary, and one piece of tissue can provide many dozen eggs, rather than the 10 or so harvested during IVF.

In addition, the technique would avoid the need for a woman to take hormone injections, which are needed in standard IVF to stimulate her ovaries to over-produce eggs.

Telfer said that there was still work to do before the laboratory-matured eggs were suitable for fertilization, but she had high hopes because animal studies had already shown that eggs matured in this way could be suitable. "We believe there's good evidence that we can get normal [eggs], but of course you would never apply this technique clinically until you are sure," said Telfer. "It might take five to 10 years from now before we get to the stage of a clinical trial."

Jane Stewart, a consultant in reproductive medicine at the Newcastle Fertility Centre, said the procedure to collect a biopsy from a woman's ovary was relatively simple and could be done at short notice. But she added: "The storage and use of such biopsies, which may contain abundant but immature eggs, remains experimental, however."

Simon Fishel, managing director of the Care Fertility Group in Nottingham, said: "Several years' work will need to be undertaken to establish if developing such immature follicles in vitro offers a risk-free option for preserving fertility."