Scientists find a way to beat the menopause

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Scientists find a way to beat the menopause

http://wrightworld.net/science.htm

 

3-18-04 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.