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http://tinyurl.com/33jh8 Scientists have discovered a new way to defy the menopause which could change women's lives, they announce today. Their research raises the prospect of extending childbearing years and offers a more natural alternative to HRT to offset ageing and maintain youthful vigour. The discovery that women may make eggs after birth, rather than be born with all the eggs they would ever have, could provide profound insights into the timing of the menopause. It is also likely to help to improve the success of grafts of ovary tissue to restore fertility in women after chemotherapy for cancer. The study overturns a theory of female fertility that has persisted for more than half a century and discloses that ovaries may have hidden reserves, a find with "significant clinical implications". The work, published in the journal Nature, was carried out at Massachusetts general hospital, Boston. Dr Marian Damewood, the president of the American Society for Reproductive Medicine, said it "could be the most significant advance in reproductive medicine since the advent of IVF more than 25 years ago". That depends on whether the research is confirmed and a way is found to tap this new-found reserve of female fertility. Every textbook on reproductive science indicates that women are born with their lifetime's complement of eggs which are steadily lost until the supply is exhausted, leading to menopause. But the textbooks may have to be rewritten. The study suggests that women continue to produce eggs after birth from special stem cells, which have been overlooked until now. The eggs derived from these cells also form new follicles, where eggs ripen, which drive the production of hormones. The project's leading author, Prof Jonathan Tilly, said yesterday: "These are basic biological findings that may change everything in our field. Although there is no way to say how long it may take for these findings to actually affect the care of patients, we are very excited." However, the study was done on mice and a leading figure in the field, Prof Roger Gosden, was cautious. He welcomed the research, but said: "Reproductive biology is very variable between species and, as yet, there is no evidence in humans contrary to the old dogma that egg production ceases before birth. "If we have been wrong, I will be astounded." If today's findings hold in humans, "all theories about the ageing of the female reproductive system will have to be revisited," said Prof Tilly. The study raises the issue of whether such things as smoking, chemotherapy and radiation could harm these stem cells and prematurely age the ovary, he said. Now the cells have been identified, ways to delay ovarian ageing - and extend fertility - can be studied. Removing, storing and reimplanting these stem cells could offer an alternative to storing mature eggs, which is difficult, for fertility preservation in cancer patients. The same approach could be used to delay the menopause. "That is something we are very excited about," said Prof Tilley. The work also suggests that therapeutic cloning - where stem cells are derived from an early cloned embryo - could make eggs for infertile women, though Prof Tilly said this was difficult to achieve. The team made the find by uncovering a "dramatic inconsistency" in the numbers of dying eggs and the reserve of eggs in juvenile and adult life. Treating prepubertal female mice with a chemical known to kill stem cells caused ovarian failure by a mechanism that did not involve destruction of eggs present at the start of the treatment. Examination of ovaries of young and mature mice identified cells on the organs' outer surface that resembled cells which are the source of eggs in foetal animals - now recognised as stem cells. The team showed that new egg cells develop and form follicles in ovarian tissue in genetically altered mice. If the work applies to women, it may explain why fertility declines after 30: that this might be due to depletion of stem cells, rather than exhaustion of an egg reserve laid down before birth. The team is trying to isolate and store the stem cells in mice so they can investigate how to prevent ovarian failure and infertility caused by ageing or cancer treatments, with a view to applying this research to women. Charlotte Woodhouse went through the menopause at the age of 14 and pins her hopes of raising a family on a breakthrough in research. For the past few years the thought of a scientific advance that could help delay or even reverse the menopause has brought comfort to the 23-year-old, who lives in Biggin Hill, Kent. In her case, the new understanding of stem cells would have to be combined with therapeutic cloning, a contentious method under development that is more hope than real substance. No matter how experimental, she hopes the work can help all women in her predicament. "It would not bother me being a guinea pig," she said. xponent More Menses Maru rob _______________________________________________ http://www.mccmedia.com/mailman/listinfo/brin-l
