NEW TECHNOLOGY MAY ALLOW WOMEN TO HAVE BABIES FROM THAWED OVARIAN TISSUE
A new technique could offer thousands of young women the chance to have babies after their ovaries have been damaged
due to treatment for diseases such as cancer.
Professor Johan Smitz told a meeting of the European Society of Human Reproduction and Embryology (ESHRE) in Tours that the technique was still in its early stages but within the next 10 years it may become possible for doctors to thaw frozen ovarian tissue previously taken from young women, remove immature eggs from it, and mature them in the lab. The eggs could then be fertilised and implanted in the woma's womb, using existing IVF techniques.
At present it is possible to create babies from frozen embryos, but it is impossible to freeze individual mature eggs (oocytes) because it destroys the eg's delicate internal structure. However, it is possible to freeze ovarian tissue which contains immature follicles (the cluster of cells containing young oocytes).
This means that for girls and young women without partners who are faced with ovarian-destroying treatment for a disease, the only hope for them at present is to have part of their ovarian tissue removed and frozen so that at a future stage scientists might be able to develop this new technique successfully.
Prof Smitz, from the Centre for Reproductive Medicine in Brussels, is investigating methods of successfully maturing follicles in the laboratory so that they grow from the very early "primordial" stage when they are only 30 to 40 micrometres in diameter through to a mature follicle of about 20 millimetres in which there would be eggs ready for fertilisation. But the follicles require a very specialised tissue culture in which to grow in the lab; indeed the culture may actually have to be changed as the follicle grows and requires different nutrients and growth promoters.
So far it has only worked in mice, and Prof Smitz said that the eggs will need to be carefully checked for any abnormalities which could lead to defects in the embryos and offspring.
"I believe that maturing eggs in the lab will open many new treatment options for infertile women," said Prof Smitz.
"Oocyte banking might enable a more flexible use of a woma's reproductive capacity and may well provide a new treatment option for women whose ovaries may be damaged by chemo or radiotherapy during cancer treatment.
"At the moment it is easy to take tissue and bank it in a freezer, but i's not so easy to know what to do with it after that. The procedure is very difficult and may take at least 10 years to develop. We would encourage cancer institutes to consider counselling for their patients so that women can fully understand the consequences of their treatment and can consider whether they would like to store their ovarian tissue
"It has been shown that for those women who have ovarian tissue in the freezer, it seems to be helpful psychologically for them to know there is some hope of being able to have babies in the future. It helps them to deal better with whatever treatment they are having for their disease."
At present doctors are able to re-implant ovarian tissue, but this process runs the risk of also re-implanting cells carrying the disease for which the woman was originally treated and which could cause the disease to recur. However diseased cells cannot enter the oocytes and therefore there is no risk of disease transmission.
ESHRE is holding its 15th annual conference in Tours, France, from Sunday, June 27 to Wednesday, June 30. It has more than 3,700 members worldwide and is one of the major international societies in the field of reproduction and embryology.
Emma Mason, Margaret Willson or Sebastien Desprez (media information officers) at the ESHRE conference press office:
Tel: +33 2 47 70 71 20/21/22
Fax: +33 2 47 70 71 45/35
Mobile:+44 (0) 411 296986 (Emma)
+44 (0) 973 853347 (Margaret)
+44 7979 850 291 (Sebastien)